i

Investigation on Mechanisms of Dynamic Formation of Criteria Gaseous Pollutants in CNG

Fired Automobile Engine

A

DISSERTATION

SUBMITTED TO DEPARTMENT OF CHEMICAL ENGINEERING

AS PARTIAL FULFILLMENT TO THE REQUIREMENTS OF THE

DEGREE OF DOCTOR OF PHILOSOPHY

IN

CHEMICAL ENGINEERING

BY

MUHAMMAD MANSHA

(2006-PhD-Chem-02)

SUPERVISOR

PROF. DR. A. R. SALEEMI

DEPARTMENT OF CHEMICAL ENGINEERING,

UNIVERSITY OF ENGINEERING AND TECHNOLOGY

LAHORE, PAKISTAN

June, 2010

iii

THIS THESIS IS EVALUATED BY:

A. External Examiners:

From Abroad

1. Dr. Qamar Zafar, Department of Chemical and Biological Engineering,

Institute of Kongsberg Oil and Gas Tech. AS,

Hamangskogen,60 1338 SANDVIKA, NORWAY.

2. Dr. Iqbal Muhammad Mujtaba, School of Engineering, Design &

Technology, University of Bradford UK

From Pakistan

Dr. Shahid Raza Malik, Chairman, Department of Chemical

Engineering, NFC Institute of Engineering and Fertilizers Research,

Faisalabad

B. Internal Examiner:

Prof. Dr. A.R. Saleemi, Dean, Faculty of Chemical, Mineral &

Metallurgical Engineering, University f Engineering and Technology,

Lahore-Pakistan.

iv

DEDICATION

LOVINGLY DEDICATED TO BELOVED

PARENTS, SWEET WIFE, CUTE SON,

HOURABLE TEACHERS AND SINCERE

FRIENDS

v

ACHNOLOWDGEMENTS

To with I have no words to pay my self effacing gratitude to the ALMIGHTY ALLAH who

gave me the audacity, resolve and serenity to complete this work. After this I pay

reverences and Darud-o-Salam to my beloved prophet HAZARAT MUHAMMAD

(SAAW) who undoubtedly is the sole reason behind the creation of the universe and course

best creature of the GOD.

Every work in general and research wok in particular is very difficult to complete within

time without the help of associated setup. A numbers of personalities have cooperated

directly or indirectly towards completion of this work, so it will be unfair if they are not

mentioned.

I would like to express my sincere gratitude to my supervisor Professor Dr. A.R. Saleemi

for all his support, continuous guidance, encouragements and the great enthusiasm he has

always shown for my work. Furthermore, his careful reading of this thesis has improved its

quality, considerably.

I highly appreciate the suggestions and guidance of Prof. Dr. Shahid Naveed, Prof. Dr

Nadeem Fero, Prof. Dr. Javed H. Naqvi and Dr. Naveed Ramzan. I am thankful to Maj

General ® Raza Hussain, Chairman SUPARCO, whose vision encouraged the young

employees of SUPARCO for higher studies,. I would like to express my appreciation to my

friend and office colleague Mr Jamal Gul, whose company has always been a great

support for me. His valuable suggestions have guided me a lot. I am really acknowledge

the guidance and encouragement of Dr. Said Rahman of SUPARCO for At the same time,

I would like to thank my senior PhD Fellows who completed their PhD degrees; Dr.

Muhammad Umar of Pakistan of Atomic Energy Commission and Dr Sulamn Quaisar, of

KRL for providing the creative and friendly atmosphere which makes work a pleasure.

vi

I would also want to appreciate the efforts and cooperation of laboratory staff in the

Department of Chemical Engineering, especially Mr. Fiaz Kirmani. Mr. Jamil, M.

Zaman, Mr. Hafeez, Mr. Zubair, Mr. Kaleem and Mr. Azam. I am also thankful to Mr.

Asghar Ali of Research Directorate and staff (Mr. Shahbaz Ahmad) of HEC Focal Person

Office for their cooperation and support in administrative work thought the stay at the

university. Finally, I thank all my family members for the love, support and trust that they

have always shown towards me.

This work has been supported financially by the Higher Education Commission of

Pakistan.

Muhammad Mansha

vii

List of Publications 1. Mansha M., Saleemi A.R and Badar Ghauri M., (2010) “Kinetic Models of Natural

Gas Combustion in an Internal Combustion Engine", Journal of Natural Gas

Chemistry, 19 (1):6-14.

2. Mansha M., Saleemi A.R, Ghauri Badar M and Ramzan Naveed, (2010)

“Development and Testing of a Detailed Kinetics Mechanism of Natural Gas

Combustion in IC Engine” Journal of Natural Gas Chemistry, 19 (2):97-106.

3. Mansha M., Saleemi A.R and Jamal Gul, (2009) “Comparative Study of Kinetic

Mechanisms for Natural gas Combustion in An Internal Combustion Engine”,

Mehran University Research Journal of Engineering & Technology, Jamshoro.

(Accepted for Publication).

4. Mansha M., Saleemi A.R, Javed S.H, and Badar M. Ghauri, (2010) “Prediction and

Measurements of Emissions of Pollutants in CNG Fired Internal Combustion

Engine”, Journal of Natural Gas Chemistry, (Accepted for Publication).

5. Mansha M., Saleemi A.R , Ramzan Naveed and Ghauri Badar M. (2010), “Study of

Construction, Investigation and Reduction of Kinetic Reaction Mechanisms of

Methane Oxidation; An Overview”, Journal of Natural Gas Chemistry, (Accepted

for Publication).

6. Mansha M., Saleemi A.R,, Javed S.H and Badar M. Ghauri, “Detailed Kinetic

Mechanisms for Prediction of Emissions of Pollutants in CNG Fired IC Engine”

Revision of is submitted “The Arabian Journal for Science and Engineering B-

Engineering (AJSE B-Engineering)”.

7. Mansha M., Saleemi A.R, Ghauri Badar M and Ramzan Naveed

(2010)“Investigation of Automatically Generated Kinetic Reaction Mechanism for

Oxidation of Simple Hydrocarbons in IC Engine”. Under Review in

Songklanakarin J. Sci. Technol.

viii

ABSTRACT

The need of alternate clean transport fuels is exponentially increasing due to stringent

environmental regulations of vehicular emissions and alarmingly depleting the current

resources of traditional transport fuels such as gasoline, diesel fuels. The world statistical

data depicts that public transport vehicles are increasingly converted to Compressed

Natural Gas (CNG) due to its environment friendly nature. The literature survey depicts

that research mainly focused on fluid dynamics aspects (such as turbulence) and flame

features (flame development, flame propagation, flame geometry etc) of combustion in

various combustions systems. In this regard, a number of studies are reported in the

literature in which the combustion of fuels (mostly single component such as methane,

ethane, propane, octane, ethanol, pentane, hydrogen etc) was simulated using the kinetic

reactions mechanisms. The limited work is reported in the literature related to the

formation of pollutants due to the combustion of CNG (a multi component gas mixture) in

automobile engines (powered by IC engines).

In present research, the combustion of CNG is simulated using the kinetic reaction

mechanisms in Internal Combustion (IC) engines. These mechanisms are primarily

investigated to predict the formation of gaseous pollutant such as Carbon monoxide (CO),

Oxides nitrogen (NO & NO2) and ammonia (NH3) due to combustion of CNG in IC engine.

A number of reaction mechanisms were developed and analyzed under the selected

simulation conditions describing the practical operating conditions of the automobile

engine. The reaction mechanisms were developed by the coupling of two reaction

mechanisms (i) a hydrocarbon reaction mechanism generated by EXGAS (an automatic

mechanism generation tool) and (ii) Leeds NOx mechanisms. Each of the mechanisms was

consisting of the hundreds of the elementary reactions of types including Unimolecular

ix

initiations, Bimolecular initiations, Additions, Isomerization, Beta-scissions,

Decompositions to o-rings, Branching, Metatheses, Combination, Dismutation. These

mechanism also contain a number of the species/radicals/intermediates such as

Monohydroperoxides (OOH), Dihydroperoxydes (OOH)2, Allylic molecules YH, , Ethers

(O), Ketones (CO), aldehydes (CHO). Each of the reaction was containing the kinetic data

(Arrhenius rate parameters; A, b or β and Ea) required to determine the rate constant (k)

using the Arrhenius Rate Law and the species thermo-chemical data (NASA Coefficients).

Each of the proposed mechanisms was implemented in IC engine module of Chemkin 4.1.1

(a kinetic simulation package) for further analysis and the four detailed reaction

mechanisms successfully predicted the combustion profiles of pressure, temperature and

selected pollutant species. These are represented by Mechanism-I, Mechanism-II and

Mechanism-III Mechanism-IV in this report. Mechanism-I is a comprehensive reaction

mechanism containing reactions feasible at range of temperature conditions (below 800 K

and above 1000 K). This mechanism is composed of 935 elementary reactions and 185

species. Mechanism-II is a high temperature (above 1000 K) reaction mechanism and

consists of 124 species and 792 elementary reactions. This mechanism composed of that

type of reaction feasibly at high temperature during the combustion of natural gas.

Mechanism-III is a low temperature (below 800 K) reaction mechanism and consists of

152 species and 864 elementary reaction. Mechanism-IV is developed by the

simplification of Mechanism-I by the chemical lumping technique and is consisting of only

72 species and 208 elementary reactions.

In the simulation study, the common inputs were; (i) fuel composition (CH4, 89.03;

C2H6, 1.5; C3H8, 0.27%; C4H10, 0.17 %, N2, 7.20% & CO2; 2.60% by vol.); (ii) engine

geometrical parameters (cylinder displacement volume, 63.0 cm3, connecting rod to crank

radius ratio, 1.632 etc). Each of the proposed mechanisms of were investigated by (a)

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Parametric Analysis (b) Rate of Production Analysis (ROP) (c) Sensitivity Analysis and (d)

Uncertainty Analysis.

In Parametric Analysis of proposed mechanism, the effect of engine operating

parameters such as engine speed, fuel to air equivalence ratio, compression ratio, initial

inlet temperature and pressure of feed mixture on the in-cylinder pressure, temperature and

pollutant species profiles were analyzed. This analysis determined that output simulation

profiles (of in-cylinder pressure, temperature, pollutant species) is greatly affected by the

engine speed and fuel to equivalence ratio under the selected simulation condition. The

rate of production analysis of each the mechanisms was carried out to identify the reactions

involved in the formation of selected pollutant species in addition to the major combustion

products (i.e. CO2 & H2O). In this analysis, the total rate of production and normalized rate

of production coefficient were calculated for each of the elementary reaction of each

mechanism at two temperature condictions of 1500 K and 4000 K. The Sensitivity Analysis

showed the dependency (sensitivity) of the output concentrations of pollutant species to the

rate constants of the reactions involved. This effect was quantified by determined the

“Logarithmic Normalized Sensitivity Coefficients” for each of the reaction involved and

showed by the sensitivity bar plot. The Uncertainty Analysis was carried out to determine

the uncertainties in the output concentrations of pollutant species due to (i) operating

parameters (such as engine speed, fuel to air equivalence ratio and compression ratio) and

(ii) due to kinetic parameters (Arrhenius parameters, A, β, Ea) for each reaction was

studied.

In simulation studies, the adiabatic flame temperature of natural gas combustion

predicted are order of ~6300 K, 4400 K, 6200 K and 8200 K for Mechanism-I, Mechanism-

II, Mechanism-III and Mechanism-IV respectively. It was also observed that adiabatic

flame temperatures increase with increasing initial gas temperature. The in-cylinder

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temperature and pressure were predicted as 4554.738 K and 39.776 atm when compression

ratio was 10.51 for Mechanism-I at equivalence ratio of 1.3 (under fuel rich operation),

compression ratio of 10.5 (design value for the tested engine), about 3000 rpm engine

speed. When combustion in IC engine was simulated with kinetic Mechanism-II (High

temperature mechanism), the maximum peak temperature and pressure was achieved at

equivalence ratio of 1.3, compression ratio of 10.51, and low engine speed of about 2000

rpm, and initial inlet temperature of 1500 K. The simulation with Mechanism-III illustrates

that the maximum peak temperature (3526.161 K) and pressure (31.27 atm) in the

combustion chamber were achieved at equivalence ratio of 1.4, compression ratio of 10.51,

engine speed of 1500 rpm (low speed) and at initial inlet temperature of 2300 K. and

pressure. The Mechanism-IV shows that the maximum peak temperature (4277.804 K) and

pressure (41.84569 atm) was achieved when equivalence ratio (Fuel/air) was ≈1.3,

compression ratio of ≈10.51, engine speed of ≈ 3000 rpm and initial inlet temperature of

≈1000 K.

For experimental measurements, an experimental setup was developed to study the

effect of various operating parameters on the CNG combustion in an automobile engine (a

type an IC engine) and to validate the simulation result obtained by the proposed kinetic

mechanisms. In this experimental study, the in-cylinder profiles of temperature, pressure

and pollutant species (CO, NO, NO2 & NH3) were recorded under various operating

conditions of an automobile engine. The simulation data for each of the proposed

mechanism is compared with experimental data for and an appropriate mechanism of CNG

combustion is selected which showed the closer agreement with the experimental results.

The average measured cylinder pressure varied from 0.61 atm to 32.62 atm for six

consecutive engine cycles. The highest concentrations of NOx were near the stoichiometric

conditions and then become lower while CO level shows increasing trend. The modeled

xii

data was compared with the experimental data (measured when engine was operated at

3000 rpm, φ=1.0, Pinlet=0.67 atm) for each proposed mechanisms.

The simulated pressure & temperature profiles of Mechanism-I exhibited the closer

agreement with those of the experimental measured profiles while the pollutant species

profiles significantly deviated. The deviation in the species profile caused because of the

reactions involved in the formation/destruction under given conditions. Similarly, the

profiles of Mechanism-II (high temperature above 1000K) and Mechanism-III (low

temperature below 800 K) exhibited the early start of the combustion which was not

supported by the experimental measurements. On the basis of these discrepancies, it is

conclude that Mechanism-I, Mechanism-II & Mechanism-III were failed in the viable

prediction of the formation pollutants and the experimental measurements did not validated

simulation result. In spite of the existence of some discrepancies among the simulation

profiles, Mechanism-IV (consisting of 208 elementary reactions & 72 species) exhibits the

closer agreement with the experimental data under the given engine operating conditions.

This mechanism is containing the reactions feasible at range of temperature conditions of

low (below 800 K) to high (1000 K). In this mechanism, major primary types of reactions

include; Unimolecular initiations, Bimolecular initiations, Beta-scissions, Oxidation,

Branching, Metatheses, Combination and Dismutation. On the basis of this, it is concluded

that Mechanism-IV is consisting of those kinds elementary reactions (both primary &

secondary type) involved in the combustion of CNG in the automobile engine and is

capable of predicting the formation of the selected criteria gaseous pollutants.

xiii

TABLE OF CONTENTS 1 Introduction 1

1.1 Introduction 2

1.2 Natural Gas as Alternative Fuel 4

1.3 Application of Chemical Reaction Mechanisms to Study

Hydrocarbon Oxidation:

6

1.4 Needs of Research 7

1.5 Objectives and Need of Current Study 8

1.6 Organization of Thesis 9

2 Literature review 11

2.1 Introduction 12

2.2 Chemical Reaction Kinetic Mechanisms; A Perspective

12

2.3 Summary of Literature Review 20

3 Generation of Kinetic Mechanisms of Natural Gas Combustion in IC Engine

22

3.1 Introduction: 22

3.2 Construction of Kinetic Reaction Mechanism 23

3.2.1. The C0-C1-C2 Reaction Base 23

3.2.2 Representation of Reaction Species 24

3.2.3 Construction of Primary Mechanisms 24

3.2.4 Construction of Secondary Mechanism 26

3.2.5. Choice of reactions to be generated and final Mechanism

30

3.3 Thermo-chemical Data Calculation 32

3.4 Kinetic Data Calculations 32

xiv

3.5 Estimation of Kinetic Data by Thermochemical Kinetics

33

3.6 Coupling of Hydrocarbon Oxidation and NOx Chemistry

39

3.7 Proposed Kinetic Reaction Mechanisms 41

3.8 Summary 42

4 Parametric Analysis of Proposed Kinetic Mechanisms of CNG combustion

44

4.1 Introduction 45

4.2 Simulation of Combustion in IC Engine by Chemkin 4.1.1 47

4.3 Operating Variables Combustion in Automobiles Engines 48

4.4 Objectives 48

4.5 Simulation of Effect of Operating Variables in CNG fired IC Engine

48

4.5.1 General Simulation Inputs

4.6 Effect of Fuel to Air Equivalence Ratio 49

4.7 Results and Discussion 53

4.8 Pollutants Formation in Automobile Engine (IC) 76

4.9 Formation of Nitrogen Containing Pollutants (NO, NO2 and NH3)

76

4.10 Kinetics of Carbon Monoxide 96

4.11 Parametric Uncertainty Analysis Using Chemkin 4.1.1 of Pollutants Formation in IC Engine

102

4.12 Summary 110

5 Sensitivity and Rate of Production Analysis of Detailed Kinetic Mechanisms

114

5.1 Introduction 115

xv

5.2 Rate of Production Analysis 115

5.3 Sensitivity Analysis of Detailed Kinetic Mechanisms 117

5.3.1 Local Sensitivity Analysis of Pollutants Formation in IC Engine

118

5.4 Rate of Production Analysis of Kinetic Mechanisms using Chemkin 4.1.1

120

5.4.1 Mechanism-I (Complete Detailed Mechanism) 122

5.4.2 Mechanism-II (High Temperature) 133

5.4.3 Mechanism-III (Low Temperature) 143

5.4.4 Mechanism-IV 155

5.5 Summary 166

6 Uncertainty Analysis of Proposed Kinetic Mechanisms

167

6.1 Introduction 168

6.2 Uncertainty Analysis of Detailed Mechanisms by Chemkin 4.1.1

169

6.3 Results and Discussion 171

6.4 Summary 186

7 Investigation of Kinetic Mechanisms of Methane Oxidation

187

7.1 Introduction 188

7.2 Implantation of Detailed and Reduced Kinetic Mechanism of Methane Oxidation in IC engine

188

7.3 Results & Discussion 194

7.4 Summary 199

8 Experimental Investigation of CNG Combustion in IC Engine and Pollutants Emissions

219

8.1 Introductions 202

xvi

8.2 Objectives 203

8.3 Description of Experimental Setup; 203

8.4 Results and Discussion 209

8.4.1 Investigation of Pressure and Temperature in Engine Cylinder

210

8.4.1.1 Cylinder Pressure and Exhaust Port Temperature

224

8.4.2 Investigation of Pollutants Formation due to

Combustion of CNG

226

8.5 Summary 246

Conclusion and Proposed Future Work 247

References 255

Annexure-I 266

Annexure-II 309

xvii

LIST OF FIGURES

Figure 1.1 Pakistan’s Energy Consumption in 2004. (Source: Pakistan Ministry of Petroleum and Natural Resources)

9

Figure 3.1 An Algorithm of Automatic Construction of Primary Mechanisms of Oxidation of Simple fuels (like Natural gas)

25

Figure 3.2 Secondary Mechanisms Generation Rules 27

Figure 3.3. Algorithm for Coupling of Hydrocarbon Oxidation Mechanism and Nitrogen Oxidation Chemistry.

40

Figure 3.4. Schematic Diagram of building Chemkin Format Kinetic Mechanisms through Coupling with OpenChem Workbench

41

Figure 4.1 Conceptual 0-D homogeneous reactor system of Engine Combustion Chamber (adopted from Heywood, 1988)

45

Figure 4.2a Parameter Input Windows for (A) Reactor Physical Properties (B) Reactant Species

52

Figure 4.2 Equilibrium Product Temperatures (Adiabatic Flame Temperature) of CNG-Air Mixture in IC Engine at Constant Pressure and Enthalpy

54

Figure 4.3a Variation in Peak Cylinder Pressure and Temperature at Various Equivalence Ratios

64

Figure 4.3b Variation in Peak Cylinder Pressure and Temperature at Various

Compression Ratios

65

Figure 4.3c Variation in Peak Cylinder Pressure and Temperature at Various Engine Operating Speeds

66

Figure 4.3d Variation in Peak Cylinder Pressure and Temperature at Various

Initial Inlet Temperatures

67

Figure 4.4. Pressure Profiles of IC Engine Cylinder operating at 3000 rpm, φ=1.0 for Combustion Simulation with Four Kinetic Relation Mechanism

69

Figure 4.5. Temperature Profiles of IC Engine Cylinder operating at 3000 rpm, φ=1.0 for Combustion Simulation with Four Kinetic Relation Mechanism

70

Figure 4.6 Predicted CO2 profiles in IC Engine Cylinder at 3000 rpm, 0.67 atm, 1500 C and φ ≈1.0.

72

xviii

Figure 4.7. Predicted H2O profiles in IC Engine Cylinder at 3000 rpm, 0.67 atm, 1500 C and φ ≈1.0.

73

Figure 4.8. Variation in Peak CO2 Mole Fractions in IC Engine simulated for four proposed Kinetic Mechanisms at various (A) equivalence ratios, (B) Speeds, (C) Initial Inlet Temperatures and (D) Compression Ratios

74

Figure 4.9. Variation in Peak H2O Mole Fractions in IC Engine simulated for four proposed Kinetic Mechanisms at various (A) equivalence ratios, (B) Speeds, (C) Initial Inlet Temperatures and (D) Compression Ratios

75

Figure 4.10 Nitric Oxide (NO) profiles at Equivalence ratio ≈ 1.0, engine speed ≈3000 rev/min, Tini =1500 °C and Pini=0.67 atm

78

Figure 4.11 Variation in Peak Molar fractions of NO formation in IC engine for Four Kinetic Mechanisms at Various (A) Equivalence Ratios, (B) Engine Speed, (C) Initial Inlet Temperature and (D) Compression Ratio

80

Figure 4.12 Reactions Involved in NO Formation in IC engine 84

Figure 4.13 Nitrogen dioxide (NO2) profiles at Equivalence ratio ≈ 1.0, engine speed ≈ 3000 rpm, Tini =1500 °C and Pini=0.67 atm

85

Figure 4.14 Variation in Peak Molar fractions of NO formation in IC engine for Four Kinetic Mechanisms at Various (A) Equivalence Ratios (B) Engine Speed and (C) Initial Inlet Temperature.

88

Figure 4.15 Ammonia (NH3) profiles at Equivalence Ratio ≈ 1.0, Engine Speed ≈ 3000 rpm, Tini =1500 °C and Pini=0.67 atm 89

Figure 4.16 Variation in Peak Molar fractions of NH3 formation in IC engine for Four Kinetic Mechanisms at Various (A) Equivalence Ratios, (B) Engine Speed and (C) Initial Inlet Temperature.

91

Figure 4.17 Carbon monoxide (CO) profiles at Equivalence Ratio ≈ 1.0, Engine Speed ≈ 3000 rev/min, Tini =1500 °C and Pini=0.67 atm

98

Figure 4.18 Variation in Peak Molar fractions of NO formation in IC engine for Four Kinetic Mechanisms at Various (A) Equivalence Ratios, (B) Engine Speed and (C) Initial Inlet Temperature

100

Figure 4.19 Percentage Contribution of Four Input Operating Variables of the Uncertain out of Concentrations of H2O(a), CO2(b), CO (c), NO (d), NO2 and NH3 in IC engine when combustion simulated for Mechanism-I

104

Figure 4.20 Percentage Contribution of Four Input Operating Variables of the Uncertain out of Concentrations of H2O(a), CO2(b), CO (c),

106

xix

NO (d), NO2 and NH3 in IC engine when combustion simulated for Mechanism-II

Figure 4.21 Percentage Contribution of Four Input Operating Variables of the Uncertain out of Concentrations of H2O(a), CO2(b), CO (c), NO (d), NO2 and NH3 in IC engine when combustion simulated for Mechanism-III

108

Figure 4.22 Percentage Contribution of Four Input Operating Variables of the Uncertain out of Concentrations of H2O(a), CO2(b), CO (c), NO (d), NO2 and NH3 in IC engine when combustion simulated for Mechanism-IV

110

Figure 5.1 Variation of Rate of Production of CO at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

123

Figure 5.2 Variation of Rate of Production of NO at Extreme Temperatures of T=1500 °C and T=4000 K in IC engine for Equivalence Ratio ≈1.0

123

Figure 5.3. Variation of Rate of Production of NO2 at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

124

Figure 5.4. Variation of Rate of Production of NH3 at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

124

Figure 5.5. CO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-I in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

128

Figure 5.6 CO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-I in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

129

Figure 5.7. NO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-I in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

130

Figure 5.8. NO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-I in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

131

Figure 5.9 NH3 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-I in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

132

Figure 5.10. Variation of Rate of Production of CO at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio

134

xx

≈1.0

Figure 5.11 Variation of Rate of Production of NO at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

134

Figure 5.12 Variation of Rate of Production of NO2 at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

135

Figure 5.13 Variation of Rate of Production of NH3 at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

135

Figure 5.14. CO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-II in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 °C

139

Figure 5.15. CO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-II in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

140

Figure 5.16 NO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-II in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 °K and (B) T=4000 K

141

Figure 5.17 NO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-II in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

142

Figure 5.18 NH3 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-II in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 °C and (B) T=4000 °C169

143

Figure 5.19 Variation of Rate of Production of CO at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

145

Figure 5.20 Variation of Rate of Production of NO at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

145

Figure5.21 Variation of Rate of Production of NO2 at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

146

Figure 5.22 Variation of Rate of Production of NH3 at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

146

xxi

Figure 5.23 CO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-III in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

150

Figure 5.24. CO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-III in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

151

Figure 5.25 NO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-III in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

152

Figure 5.26 NO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-III in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

153

Figure 5.27 NH3 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-III in IC engine at equivalence ratio =1.0 and engine speed at 3000 when (A) T=1500 K and (B) T=4000 K

154

Figure 5.28 Variation of Rate of Production of CO at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

155

Figure 5.29 Variation of Rate of Production of NO at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

156

Figure 5.30 Variation of Rate of Production of NO2 at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

156

Figure 5.31 Variation of Rate of Production of NH3 at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

157

Figure 5.32 CO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-IV in IC engine at equivalence ratio =1.0 when (A) T=1500 K and (B) T=4000 K

161

Figure 5.33 CO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-IV in IC engine at equivalence ratio =1.0 when (A) T=1500 K and (B) T=4000 K

162

Figure 5.34 NO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-IV in IC engine at equivalence ratio =1.0 when (A) T=1500 K and (B) T=4000 K

163

Figure 5.35 NO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-IV in IC engine at equivalence ratio =1.0 when (A)

164

xxii

T=1500 K and (B) T=4000 K

Figure 5.36 NH3 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-IV in IC engine at equivalence ratio =1.0 when (A) T=1500 K and (B) T=4000 K

165

Figure 6.1 Major reactions contributing to the uncertainty of Pollutant Species CO, NO, NO2 and NH3 concentrations at Equivalence ratio =1.0, 3000 rpm, T=1500 K and P=1.0 atm for kinetic Mechanism-I

174

Figure 6.2 Major reactions contributing to the uncertainty of Pollutant Species CO, NO, NO2 and NH3 concentrations at Equivalence ratio =1.0, 3000 rpm, T=1500 K and P=1.0 atm for kinetic Mechanism-II

178

Figure 6.3 Major reactions contributing to the uncertainty of Pollutant Species CO, NO, NO2 and NH3 concentrations at Equivalence ratio =1.0, 3000 rpm, T=1500 K and P=1.0 atm for kinetic Mechanism-III

181

Figure 6.4 Major reactions contributing to the uncertainty of Pollutant Species CO, NO, NO2 and NH3 concentrations at Equivalence ratio =1.0, 3000 rpm, T=1500 K and P=1.0 atm for kinetic Mechanism-IV

185

Figure 7.1 Predicted Pressure Profiles for Equivalence Ratio of φ =1.0 (Tini=447 K, Pini=1.07 bar)

195

Figure 7.2 Predicted Temperature Profiles for Equivalence Ratio of φ =1.0 (Tini=447 K, Pini=1.07 bar)

196

Figure 7.3 Major Species Profiles for Equivalence Ratio of φ =1.0 (Tini=447 K, Pini=1.07 bar).

198

Figure 7.4 NOx and CO Emissions for Equivalence Ratio of φ =1.0 (Tini=447 K, Pini=1.07 bar). [Note; NOx is used as collective term for NO2 & N2O]

199

Figure 8.1 Schematic Diagram of Experimental Setup. 206

Figure 8.2 View of Experimental Setup showing Gas Analyzers 207

Figure 8.3 Side View of Experimental Setup showing different Components of Experimental Setup

207

Figure 8.4 Diode-laser-based Spark Plug used in this study 208

Figure 8.5 Installation of Spark-plug Ignition System in Combustion Chamber of Tested IC Engine showing [1] inflamed spherical volume, [2] piston ring, [3] piston cavity, and [4] fused silica

208

xxiii

optical window.

Figure 8.6 Cylinder Pressure Measurements for Six Successive Cycles in CNG fired IC Engine operating at 3000 rpm, φ=1.0, Pinilet=0.67 atm.

213

Figure 8.7 Variation in Cylinder Pressure ((Average)) Measured for Six Successive Cycles in CNG fired IC Engine operating at 3000 rpm, φ=1.0, Pinlet =0.67 atm.

214

Figure 8.8 Measured Cylinder Pressure at Various Equivalence Ratios of CNG Fired IC Engine operating at 3000 rpm, Pinilet=0.67 atm

216

Figure 8.9 Measured Cylinder Pressure for Various Fuels of IC engine Operating at 3000 rpm and φ=1.0

218

Figure 8.10 Pressure Profiles for Four Proposed Kinetic Models (simulation with IC modules of Chemkin 4.1.1 and Experimental Cylinder Pressure data

220

Figure 8.11 Average Cylinder Temperature of Six (06) Successive Operating Cycles of Engine operating at 300 rpm, φ=1.0, Pinilet=0.67 atm

221

Figure 8.12. Measured Cylinder Temperatures at Various Equivalence Ratios of CNG Fired IC Engine operating at 3000 rpm, Pinilet=0.67 atm

222

Figure 8.13 Measured Cylinder Temperature for Various Fuels of IC engine Operating at 3000 rpm and φ=1.0

224

Figure 8.14 Exhaust Gas Measured Temperature at Exhaust Port Exit and Measured Cylinder Pressure, atm of CNG Fired IC Engine Operating at 3000 rpm, 0.67 atm, φ=1. 3

225

Figure 8.15. Measured NOx Concentrations (In-Cylinder) for Three Fuel (3000 rev/min, φ=1.0 and Pinlet =0.67 atm)

238

Figure 8.16 Variation of CO and NOx concentration in Exhaust of CNG fired IC Engine (200 CC) at Various Equivalence Ratio (Fuel/Ratio)

229

Figure 8.17 Variation in Concentrations of NO and NO2 in Engine Exhaust as function of Equivalence Ratio

230

Figure 8.18 Comparison of NOx Profiles (with Modeled data and Experimental data).

231

Figure 8.19 Variation of NOx Concentrations (Exhaust) for Different Fuels when Engine was operating at 3000 rpm

233

Figure 8.20 Variation of NOx Concentrations (In-Cylinder) for Different Fuels

234

xxiv

Figure 8.21 Variation of Ratio of In-Cylinder and Exhaust Concentrations of Oxides of Nitrogen (NOx) for Three Fuels.

234

Figure 8.22 Measured NOx in Engine Exhaust at various Engine Speeds for Fuel-A

236

Figure 8.23 NOx Levels at Various Distances from the Exhaust Port engine Operating at 3000 rpm.

237

Figure 8.24 Measured CO Concentrations (In-Cylinder) for Three Fuel (3000 rev/min, φ=1.0 and Pinlet =0.67 atm)

239

Figure 8.25 Variation in CO Emissions from CNG fired IC Engine (Speed; 3000 rpm, Texit=300 °C)

240

Figure 8.26 Variation in CO Concentrations (In-Cylinder) from CNG fired IC Engine (Speed; 3000 rpm)

241

Figure 8.27 Variation of Ratio of In-Cylinder and Exhaust Concentrations of Oxides of Nitrogen (NOx) for Three Fuels.

242

Figure 8.28 CO Levels at Various Distances from the Exhaust Port engine Operating at 3000 rpm for Fuel-A (Commercial CNG)

242

Figure 8.29 Measured CO in Engine Exhaust at various Engine Speeds for Fuel-A

243

Figure 8.30 Comparison of CO Profiles (with Modeled data and Experimental data).

244

xxv

List of Tables

Table 1.1 Emission Data from Gasoline and CNG Fuels 5

Table 3.1 The menu proposed for generating a primary mechanism 30

Table 3.2 Calculation of Rate Constants of Free Radicals of Internal

Isomerizations during Automatic Mechanism Generation 34

Table 3.3a Arrhenius (Kinetic) parameters for the oxidation of alkanes of Generated Primary Mechanisms

35

Table 3.3b Kinetic Parameters for other Reactions 36

Table 3.4a Primary Reactions in Different Reaction Mechanisms for Natural Gas Oxidation generated by EXGAS

37

Table 3.4b Number of Primary Reactions Considered in Different Reaction Mechanisms for Natural Gas Oxidation generated by EXGAS

37

Table 3.4c Different Primary Molecules Classes in Four Reaction Mechanisms of Natural Gas Oxidation generated by EXGAS

38

Table 3.5 Intermediate and Product Species and Radicals in Each Kinetic Mechanism

42

Table 4.1 Typical Engine Geometrical Input Parameters and Initial Gas (Feed) Mixture Composition

49

Table 4.2a Input Operating Parameters to Study the Effect of Equivalence Ratio for Four Kinetic Mechanisms

50

Table4.2b Input Operating Parameters to Study the Effect of Compression Ratio for Four Kinetic Mechanisms

50

Table 4.2c Input Operating Parameters to Study the Effect of Engine Speed for Four Kinetic Mechanisms

51

Table 4.2d Typical Input Operating Parameters to Study the Effect of Initial Inlet Temperature for Four Kinetic Mechanisms

51

Table 4.3a Predicted Peak Combustion Temperatures and Pressure (Mechanism-I)

55

Table 4.3b Predicted Peak Combustion Temperatures and Pressure at Various Compression Ratios (Mechanism-I)

55

Table 4.3c Predicted Peak Combustion Temperature and Pressure at Various 55

xxvi

Inlet Temperatures (Mechanism-I)

Table 4.3d Predicted Peak Combustion Temperature and Pressure at Various Inlet Temperatures (Mechanism-I)

56

Table 4.4a Predicted Peak Combustion Temperatures and Pressure (Mechanism-II)

56

Table 4.4b Predicted Peak Combustion Temperature and Pressure at Various

Compression Ratios (Mechanism-II) 56

Table 4.4c Predicted Peak Combustion Temperature and Pressure at Various Engine Operating Speeds (Mechanism-II)

56

Table 4.4d Predicted Peak Combustion Temperature and Pressure at Various Inlet Temperatures (Mechanism-II)

57

Table 4.5a Predicted Peak Combustion Temperatures and Pressure (Mechanism-III)

57

Table 4.5b Predicted Peak Combustion Temperature and Pressure at Various Compression Ratios (Mechanism-III)

57

Table 4.5c Predicted Peak Combustion Temperature and Pressure at Various Engine Operating Speeds (Mechanism-III)

57

Table 4.5d. Predicted Peak Combustion Temperature and Pressure at Various Inlet Temperatures (Mechanism-III)

57

Table 4.6a. Predicted Peak Combustion Temperature and Pressure (Mechanism-IV)

58

Table 4.6b Predicted Peak Combustion Temperature and Pressure at Various Compression Ratios (Mechanism-IV)

58

Table 4.6c Predicted Peak Combustion Temperature and Pressure at Various Engine Operating Speeds (Mechanism-IV)

58

Table 4.6d Predicted Peak Combustion Temperature and Pressure at Various Inlet Temperatures (Mechanism-IV)

58

Table 4.7a. Peak Concentrations (Mole Fraction) of NO at Various Equivalence ratios for Four Kinetic Mechanisms

78

Table 4.7b Peak Concentrations (Mole Fraction) of NO at Various Engine Speeds for Four Kinetic Mechanisms

79

Table 4.7c Peak Concentrations (Mole Fraction) of NO at Various Initial Inlet Temperatures for Four Kinetic Mechanisms

79

Table 4.7d Peak Concentrations (Mole Fraction) of NO at Various Compression 79

xxvii

Ratios for Four Kinetic Mechanisms

Table 4.8a Peak Concentrations (Mole Fraction) of NO2 at Various Equivalence

ratios for Four Kinetic Mechanisms 86

Table 4.8b Peak Concentrations (Mole Fraction) of NO2 at Various Engine Speeds for Four Kinetic Mechanisms

87

Table 4.8c Peak Concentrations (Mole Fraction) of NO2 at Various Initial Inlet Temperatures for Four Kinetic Mechanisms

87

Table 4.8d. Peak Concentrations (Mole Fraction) of NO2 at Various Compression Ratios for Four Kinetic Mechanisms

87

Table 4.9a Peak Concentrations (Mole Fraction) of NH3 at Various Equivalence ratios for Four Kinetic Mechanisms

89

Table 4.9b Peak Concentrations (Mole Fraction) of NH3 at Various Engine Speeds for Four Kinetic Mechanisms

90

Table 4.9c Peak Concentrations (Mole Fraction) of NH3 at Various Initial Inlet Temperatures for Four Kinetic Mechanisms

90

Table 4.10 Some Important Reactions and Parameters of rate coefficient k of Reversible Reaction for mechanism of Nitrogen compounds in proposed Reaction Mechanisms (A units mole-cm-sec-K, E units cal/mole)

92

Table 4.11a Peak Concentrations (Mole Fraction) of CO at Various Equivalence ratios for Four Kinetic Mechanisms

98

Table 4.11b Peak Concentrations (Mole Fraction) of CO at Various Initial Inlet Temperatures for Four Kinetic Mechanisms

99

Table 4.11c Peak Concentrations (Mole Fraction) of CO at Various Engine Speeds for Four Kinetic Mechanisms

99

Table 4.11d Peak Concentrations (Mole Fraction) of CO at Various Compression Ratios for Four Kinetic Mechanisms

99

Table 4.12 Reactions in Four Kinetic Mechanisms (Proposed) in CO Formation and Consumption

101

Table 4.13 Reactions Involved in Formation and Consumption of Pollutants in IC Engine

111

Table 5.1 Typical Engine Geometrical Input Parameters and Gas Mixture Composition

121

Table 5.2 Common Input Variables for Rate of Production Analysis and 121

xxviii

Sensitivity Analysis (Local) of Kinetic Mechanisms

Table 5.2a Key words Input for Rate of Production and Sensitivity Analysis of Kinetic Mechanisms

121

Table 5.3 Rate of Production Coefficients of Reactions Contributing in Formation of Pollutants in Mechanism-I

125

Table 5.4 Rate of Production Coefficients of Reactions Contributing in Formation of Pollutants in Mechanism-II

136

Table 5.5 Rate of Production Coefficients of Reactions Contributing in Formation of Pollutants in Mechanism-III

147

Table 5.6 Rate of Production Coefficients of Reactions Contributing in Formation of Pollutants in Mechanism-IV

157

Table 6.1 Error Analysis of Mechanism-I for Output Pollutants Species Concentrations

172

Table 6.2 Error Analysis of Mechanism-II for Output Pollutants Species Concentrations

176

Table 6.3 Error Analysis of Mechanism-III for Output Pollutants Species Concentrations

179

Table 6.4 Error Analysis of Mechanism-IV for Output Pollutants Species Concentrations

183

Table 7.1 Tested Models of Methane Combustion 189

Table 7.2 Important Species Considered in UBC MECH 2.0 and GRI MECH 3.0 Kinetic Models

189

Table 7.3. Some Important Reactions of GRI MECH 3.0 Mechanism (Pressure & Temperature dependent Reactions are listed)

190

Table 7.4 Some Important Reactions of UBC MECH2.0 Mechanism (only Pressure & Temperature dependent Reactions are listed)

192

Table 7.5 Example of Test Engines Specifications used in Simulation of Methane Combustion

193

Table 7.6 General Input Parameters 194

Table 7.7 Composition (Mole Fraction) of Initial Gas Mixture 194

Table 8.1 Experimental Setup Components 208

Table 8.1a. Specification Tested Engine used in 4-Stoke Automobile Rickshaws.

209

xxix

Table. 8.1b Fuel Composition (Mole Fraction) 210

Table 8.2. Input Variables for Simulating CNG Combustion in IC Engine 219

Table 8.2a Peak Cylinder Temperature and Pressure at Various Equivalence Ratios

223

Table 8.3 Reactions Involved in Formation and Consumption of NOx (NO & NO2) in Proposed Four Kinetic Mechanisms with Calculated Normalized Rate of Production Coefficients

232

Table 8.4 Reactions in Four Kinetic Mechanisms (Proposed) in CO Formation and Consumption

245

.

xxx

NOMENCLATURE

Δni.rot change in the number of internal notations as reactant to move the transition

state

e base of natural logarithm,

h plank constant,

kB Boltzman constant,

R gas constant,

rpd reaction path degeneracy equal to the number of abstractable H-atom,

T temperature (K

Eabst. Activation energy for a H-atom abstraction

Ecycle Strain energy of cyclic compounds

lR-R' Length of the R-R' bond

μ reduced molar mass

P Steric factor, empirically estimated

A Arrhenius Temperature Coefficient

E Activation Energy

Wk molecular weight of the kth species, and

V volume of the system, which

Xk is the molar concentration of the kth species and

kfi forward rate constants of the ith reaction

kri reverse rate constants of the ith reaction.

Tini Initial Inlet Temperature

Pini Initial Inlet Pressure

k+ rate constants in the forward directions

xxxi

k- rate constants in reverse directions

Xpi net rate of production of the product species

XRi net rate of removal of reactant species

Pk The molar production of a species per unit volume

qi Rate of progress of the gas-phase reactions.

S sensitivity matrix,

Sij sensitivity coefficient

GREEK LETTERS

γ compression ratio

ν Stoichiometric coefficients

υki Stoichiometric coefficients for the gas reactions,

φ Fuel/Air Equivalence ratio

β Temperature Coefficient

ώk molar production rate of the kth species by elementary reaction,

LIST OF ABBREVIATION

NG Natural Gas

ICE Internal Combustion Engine

CO Carbon monoxide

NOx Oxides of nitrogen

NO2 Nitrogen dioxide

NGVs Natural Gas Vehicle

CNG Compressed Natural Gas

LPG Liquefied Petroleum Gas

OGJ Oil and Gas Journal

xxxii

HC Hydrocarbon

NH3 Ammonia

GRI3.0 Gas Research Institute Mechanism version 3.0

UBC 2.0 University of Berkeley, California Mechanism version 2.0

CFD Computational Fluid Dynamics

ROP Rate of Production Analysis

ARM Argument Reduced Mechanism

DRG Direct Relation Graph

CSP Computational Singular Perturbation

DRGEP Directed Relation Graph with Error Propagation

SI Spark Ignition

SA Sensitivity Analysis

UA Uncertainty Analysis

HCCI Homogeneous Charge Compression Ignition

SOC Start of Combustion

ODEs Ordinary Differential Equations

ICEN Internal Combustion Engine

TRAN Transient Solver

EQUI Equivalence Ratio

PRES Pressure

TEMP Temperature

CMPR Engine Compression Ratio

DEG Starting Crank Angle (degrees)

LOLR Engine Connecting Rod to Crank Radius Ratio

RPM Engine Speed (rpm)

xxxiii

VOLD Engine Cylinder

CPROD Complete-Combustion Products

SDIR Staggered Direct Method

LSEN Local Sensitivity Method

DELT Time Interval for Printing

ASEN A-factor Sensitivity

ATC After Top Center

TC Top Center

TDC Top Dead Center

IVC Intake Valve Close

TDC Top Dead Center

BTDC Bottom Dead Center

r.p.m revolution per minute

1

CHAPTER- 1

INTRODUCTION

1.1 Introduction:

In this chapter, the major focus is towards discussion

of (i) the natural gas as alternative transport fuel and (ii)

application of kinetic mechanisms for studying the

oxidation of various fuels. This discussion leads towards the

background, research needs, major motives and objectives

of the current study. The literate survey indicates that the

kinetic mechanisms can be widely used to simulate the

combustion of the various fuels. In the current study, these

kinetic mechanisms are employed to simulate the

combustion of CNG in automobile engines to understand

the formation of the pollutant species such as CO, NO, NO2

& NH3 in addition to the major combustion products.

At end of this chapter, the organization of the thesis

reported is presented

2

Air pollution is becoming a serious urban as well as global problem with the

increasing population and its subsequent demands. The vehicular transport is the major

source of pollution emitting to the atmosphere. Pollution due to traffic constitute up to 90 –

95% of the ambient CO levels, 80 – 90% of NOx, hydrocarbon and particulate matter in the

world, posing a serious threat to human health (Savile, 1993). The automobile exhaust

gases conation oxides of nitrogen (NO and NO2 collectively known as NOx), carbon

monoxide (CO), and organic compounds which are unburned or partially burned

hydrocarbons (HC) in addition to combustion products (CO2 and H2O). The relative

amounts depend on engine design and operating conditions but mostly are of order: NOx ,

500 to 1000 ppm or 20 g/kg fuel; CO, 1 to 2 percent or 200 g/kg fuel; and HC, 3000 ppm

(as C1 ) or 25 g/kg fuel (Heywood, 1988).

Research conducted during last decade has shown that transportation sources in the

USA were responsible for 77% of CO levels, 80 – 90% of NOx, 36% of volatile organic

compounds and 22% of particulate matter (USEPA,1993). Similarly, in UK the average

concentration of NO2 was found to increase by 35% from 1986 to 1991 due to increase in

vehicular emissions (CEC, 1992). This has resulted in an increase in using Natural Gas

(NG) as fuel for internal combustion engines. The other reasons due to which the natural

gas is gaining attraction as alternative transport fuel are because it has resources are vast,

widespread geographically and are not limited to politically sensitive locations as is crude

oil.

In most developing countries of the world vehicular growth has not been checked

properly by environmental regulating authorities leading to increase levels of pollution.

Traffic emissions contribute about 50-80% of NO2 and CO concentration in developing

countries (Fu, 2001; Goyal, 2006). This situation is alarming and is predicated on the poor

economic disposition of developing countries. Poor vehicle maintenance culture and

3

importation of old vehicles which culminate to an automobile fleet dominated by a class of

vehicles known as ‘’super emitters’’ with high emission of harmful pollutants, has raised

high this figure of emission concentration. Furthermore, in developing countries the super

emitters contribute about 50% of harmful emissions to the entire average emission

(Brunekeef, 2005). In Mexico City for example these supper emitters are reported to be

responsible for 90% of hydrocarbon and CO emissions and 80% of NOx emissions

accounting for 60% of the kilometres traveled in the country (OECD, 1999). The increase

of this traffic-related pollution is not based on the aforementioned factors only, but also on

low quality fuel, poor traffic regulation and lack of air quality implementation force. These

are clear indices to high levels of traffic-related pollution in developing countries. Ghuari et

al., (2007) stated that the highest concentrations of CO were observed at Quetta (14 ppm)

while other pollutants like SO2 (52.5 ppb), NOx (60.75 ppb) and O3 (50 ppb) were higher at

Lahore compared to other urban centers like Karachi, Peshawar etc. The maximum

particulate (TSP) and PM10 levels were observed at Lahore (996 µg/m3 and 368 µg/m3

respectively), Quetta (778 µg/m3, 298 µg/m3) and in Karachi (410 µg/m3, 302 µg/m3). In all

major cities the highest levels were recorded at major intersections and variations were

directly correlated with traffic density.

The review these studies highlighted that vehicular exhaust is containing harmful

substances (CO, NO, NO2, NH3, HCs etc) emitting to the atmosphere. These pollutants

species are formed due to combustion of fuel in an automobile engine. It is very interesting

to understand the formation mechanisms of these pollutants in order to reduce their

growing concentration in the atmosphere.

1.2 Natural Gas as Alternative Fuel:

4

It is well known that fossil fuel reserves all over the world are diminishing at an

alarming rate and a shortage of crude oil is expected at the early decades of this century.

Probably in this century, it is believed that crude oil and petroleum products will become

very scare and costly to find and produce. Gasoline and diesel will become scarce and most

costly (Hollnagel, 1999).

The natural gas is an emerging alternative fuel due to its environmental friendly

characteristics of lower emission. Andrea et al, (1993) concluded that because of lesser cost

than other types of fuels, and accessible in countries where there are existing distribution

infrastructures, CNG appears to be capable of performing a prominent role among

alternative fuels. In this study, it is also highlighted that the usage of CNG, as a fuel for IC

engine, resulted in the reduction of pollutant emissions due to its high octane number. It

can be used in engines with high compression ratio in spark ignition engines which

consequently improves their efficiency. Many research groups did the research to substitute

fossil fuel oil to another alternative fuel (Shashikantha, 1999; Kato et al, 1999; Hollnagel,

1999; Sera et al, 2003; Czerwinski, 1999; Cho et al, 2007; Shasby et al, 2004 and Bakar et

al, 2007). Natural gas is found in various locations in oil and gas bearing sand strata located

at various depths below the earth surface (Hollnagel, 1999 and Shasby et al, 2004). Kirti et

al, (2005) presented the an elaborative review of various performance parameters and

concerns for better understanding of engine operating conditions for both spark ignition

and compression ignition engines.

Bakhshan et al, (2008) developed a multi-dimensional model to predict the

performance of CNG used as fuel. Shahrir et al, (2008) studied combustion process in a

compressed natural gas direct injection engine through numerical analysis. Numerical

calculations are now necessary to provide an insight into the complex in-cylinder process.

The combustion process and its emission characteristics in a compressed natural gas direct

5

injection engine were analyzed and investigated in this study. The Computational Fluid

Dynamics (CFD) simulations at two baseline conditions are carried out to examine the fluid

flow, air-fuel mixing formation, combustion process, carbon monoxide emission

distribution as well as NO emission formation occurred inside engine cylinder. The

examined engine performance is in-cylinder pressure, while the considered emissions to be

minimized are CO and NO levels. Bandela and Tar (2008) in his research article examined

decrease in ambient air pollution loads after vehicles in Mumbai, India, were required to

begin using cleaner fuels such as CNG rather than diesel or petrol (gasoline) and conclude

that using compressed natural gas can significantly improve air quality

Rahmat et al (2008) conducted a study using bi-fuels (Petrol and CNG) and

compared the emissions from the tested automobile engine. In their study, they concluded

that the emission with usage of CNG in automobile engine shows significant decrease in

hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO2) and nitrogen oxide (NOx)

over the use of petrol (Table 1.1). In terms of cost, the use of CNG provides savings

exceeding 50% through all engine rpm compared to petrol non-loaded operations. All this

factors proves the benefits of natural gas over petrol operations. Based on current

consumption rate, the estimated total, recoverable gas, including proven reserves, it

adequate for almost 200 years

Table 1.1 Emission Data from Gasoline and CNG Fuels (Rahmat et al, 2008)

Fuels RPM CO (%) CO2 (%) O2 (%) NOx (ppm) HC (ppm)

Gasoline

1239 0.7 11.33 3.19 129 142 2037 1.33 11.86 1.73 159 82 2928 0.41 13.33 0.48 364 47 4219 2.3 11.98 0.4 701 1745264 0.55 12.37 1.67 1158 388

CNG

863 0.04 4.91 11.48 26 776 2082 0.11 8.74 4.33 84 62 3430 0.12 10.03 1.9 194 29 4257 0.29 10.48 0.59 373 50 5073 0.44 10 1.1 805 133

6

Semin et al, (2009) reviewed the literature as pointed out five reasons to Compressed

Natural Gas (CNG) as an attractive alternative fuel. (i), because it is the only fuel cheaper

than gasoline or diesel, (ii) inherently lower air pollution emissions, (iii) lower greenhouse

gas emissions, (iv) extended petroleum supplies and (v) larger quantities of the fuel

available in the world. This study also pointed the major problems needed to be solved

when using natural gas engines. Haeng et al, (2009) carried out the Benefit Analysis of

CNG as an automobile fuel. This research highlighted the characteristics of CNG vehicles,

CNG arrangement in the vehicles, CNG fueling procedures and most importantly the

environmental and economic factors that are highly considered as cost effective solution

for the flexibility of using CNG in the automobiles. Semin et al, (2009) discussed the

engine cylinder fluid characteristics of diesel fired engine which were converted to CNG

engines. The simulation results showed the characteristics of in cylinder volumetric

efficiency profile, percent burned mass, fuel/air ratio, fuel flow profile, total fuel

consumption and total fuel energy entering to cylinder in variations engine speeds.

The reaction kinetics of CNG is important subject for understanding the combustion

chemistry and pollutants formation. It is therefore necessary to develop combustion

mechanism of CNG that are capable to predict the pollutants formation. This understanding

will help to control their emissions.

1.3 Application of Chemical Reaction Mechanisms to Study

Hydrocarbon Oxidation:

Chemical mechanisms have been employed for many years in hydrocarbon

combustion (Lewis, 1961). Initially they were used as a means of understanding the

underlying phenomenology of the combustion process in terms of the elementary reactions

7

of individual species. The various research groups developed kinetic mechanism (manually

& automatically) to study the combustion of various kinds of fuels in various systems. For

example; Halsteadt et al. (1975), Westbrook and Dryer (1981), Duterque et al, (1981),

Hutmann et al, (1981), Cox et al, (1985), Westbrook (1985), Peters (1985), Glarborg et al,

(1986), Chinnick et al. (1988), Jones and Lindstedt (1988), Miller and Bowman (1989),

Smooke et al, (1991), Warnatz (1992), Peters (1993), Walker, R. W, and Morley, C,

(1997), Anders et al, (1998, 2001), Amano et al, (1998), Lester et al, (2000), Fournet et al,

(2000), Glaude et al, (2000), Huges et al, (2001), Ellinger et al, (2001), Smith et al, (2001),

Tianfeng et al, (2001), Binita et al, (2003), Tianfeng et al, (2005, 2006), Sauro Pierucci and

Eliseo Ranzi, (2007), Ridha et al, (2008), J-Y.Chen et al, (2008) and Manshsa, et al,

(2010). In these studies, the researchers discussed the mechanism of single component

fuels such as hydrogen, hydrogen peroxide, methane, propane, octane, heptane etc. to study

fluid dynamics aspect such as flame development, propagation, flame geometry and

turbulence for various systems of combustion.

The limited data is reported of application of kinetic mechanisms of fuels used in

automobile engines (IC engines) especially for CNG fuel which is a multi-component fuel.

There is an urgent need to conduct research work to understand combustion mechanisms

kinetic related with the multi-component fuel such as CNG which is widely used. The

understanding of combustion mechanism will form the basis and foundation for emission

control.

1.4 Needs of Research:

Until today, the major concerns in the usage of internal combustion engines are

focused on economical operation and environment protection. The environmental issues are

addressed through technological design modifications and introduction of alternative

(environmental friendly) fuels in transport sector. Compressed Natural Gas is replacing the

8

conventional vehicular transport fuels (Gasoline & Diesel) in most of the parts of the

worlds because natural gas is the most favorite for fossil fuel substitution and has been

recognized as one of the promising alternative fuel due to its substantial benefits compared

to gasoline and diesel. These include lower fuel cost, higher octane and most certainly,

cleaner exhaust gas emissions. It is important to understand the formation of pollutant (CO,

NO, NO2 & NH3) in addition to major combustion products and kinetic mechanisms are the

important tool to describe the reaction may involve in the formation & destruction of

pollutant species. After the establishing the reactions contributing the formation of the

pollutants, effective control options can be adopted or developed at the source (in

combustion chamber).

1.5 Objectives and Need of Current Study:

In present work, the major objective is to explore the kinetic mechanisms lead to the

formation of emissions in CNG fired automobile (IC) engine. The specific objectives were

to investigate the reaction mechanisms under range of operating conditions of the

automobile engine. The detail objectives of this study include;

• Development of hypothetical reactions mechanisms (models) to simulate the

combustion of CNG in automobile engines.

• Coupling of reaction mechanisms schemes with nitrogen oxidation reaction

to build comprehensive detailed reaction mechanisms of CNG.

• Parametric analysis of proposed reactions mechanisms under various

operating conditions of the IC engine with Chemkin 4.1.1 (simulation

software).

• Identification of reactions in the proposed schemes involved in the

formation of pollutants in IC engine through the Rate of Production

9

Analysis (ROP), Local Sensitivity Analysis (SA) and Uncertainty Analysis

(UA) of the proposed detailed kinetic reaction mechanisms.

• Designing and fabrication of an experimental setup for validation of

simulation results.

• Selection of appropriate reaction mechanism capable to predict emissions

(gaseous pollutants) in order to establish control strategies for emissions.

1.6 Organization of Thesis:

This thesis describes the kinetic reaction mechanisms developed to simulate the

emissions of CNG fired automobile engine (IC engine). It is divided into eight chapters

describing the literature review, simulation and experimental results and findings.

In Chapter-1 of this thesis, how vehicular emissions are posing threat to the

environments, introduction of CNG as greener alternate fuels to combat the vehicular

emissions, the status of vehicular emissions in Pakistan & CNG in Pakistan and emissions

from IC engine. In the end of this chapter, objectives and need of this study are presented.

Chapter-2 presents the review of literature describing various application and analysis

techniques of detailed kinetic reaction mechanisms. In Chapter-3, the methodology of

generation of kinetic reaction mechanisms of natural gas along with required thermo-

chemical data. Four developed reactions models (mechanisms) are also discussed in his

chapter. Chapter-4 of the thesis presents the parametric analysis of four detailed kinetic

reactions models simulating the natural gas combustion in IC engine using Chemkin 4.1.1.

The effects of various operating parameters such as fuel/air equivalence ratio, engine

speed, and initial temperature of gas mixture charged into engine chamber and compression

ratio are discussed. The discrepancies and limitations of each reaction mechanisms are also

discussed. At the end of this chapter, effect of uncertainty (Parametric Uncertainty

Analysis) in input variables on the predicted profiles of formation of pollutants is

10

discussed. Chapter-5 presents the feasibility of application of various developed reaction

schemes (GRI 3.0, UBC 2.0, etc) of methane oxidation in IC engine to predict the

emissions are discussed. Chapter-6 presents the results of two important techniques i.e. rate

of production analysis and local sensitivity analysis to analyze the four proposed reaction

mechanisms and identified the reactions in proposed reaction mechanisms contributing the

concentrations of gaseous pollutants. Chapter-7 described the uncertainty analysis of four

proposed reaction models and presents the effects of kinetic parameters (Arrhenius rate

coefficients of rate constant) of reactions of mechanisms is discussed in this chapter.

Chapter-8 presents the experimental results conducted on the experimental setup

developed for this study. The experimental data of engine cylinder temperature, pressure,

emission profiles is discussed and comparison of experimental data and simulation result

compared with those of the results obtained with Chemkin 4.1.1 simulation software and

identified the appropriate mechanism closely describing the combustion of CNG in IC

engine. The conclusion and further research areas are discussed in the end of this chapter.

References, Annexure-I and Annexure-II showing the four reaction mechanism and

relevant thermo-chemical data respectively, are given at the end.

11

CHAPTER-2

Literature Review

This chapter presents the chronically review of the research

studies in which the reaction mechanisms (models) were

utilized to simulate the combustion of hydrocarbon fuels in

various combustion systems. The review of literature showed

that in the reported studies, major objective was to investigate

the fluid dynamics aspects of combustion such as turbulence

etc. The reviewed literature lead to identify the area of present

research work as the limited studies are available in which

combustion of natural gas in internal combustion (IC) engine

were studied with the primary objective mechanisms of the

pollutants formation. The reported literature indicated that

reaction mechanisms can be used to simulate the combustion

of compressed natural gas in automobile engines.

12

2.1 Introduction:

The vehicular exhaust of is consisting of sulfur oxides, nitrogen oxides, unburned

hydrocarbons, and oxygenated species in addition to the major combustion products such

as CO2, H2O (Heywood, 1988). The quantitative description of the formation of these

species from the combustion of the hydrocarbons (alkanes, alkenes, naphtenes, aromatics,

ethers, etc.) contained in fuels requires to write detailed reaction mechanisms involving a

large number of chemical species and elementary reactions (Fournet et. al, 2000).

2.2 Chemical Reaction Kinetic Mechanisms-A perspective:

Chemical mechanisms have been employed for many years in hydrocarbon

combustion. Initially they were used as a means of understanding the underlying

phenomenology of the combustion process in terms of the elementary reactions of

individual species (Lewis et al, 1961).

One of the first numerical studies was performed by Halsteadt et al. (1975) with the

so-called “Shell model,” involving symbolic equations corresponding to initiation,

propagation, branching and termination reactions controlling the amount of a reactive

species.

Westbrook and Dryer (1981) examined the simplified reaction mechanisms for the

oxidation of hydrocarbon fuels using a numerical laminar flame model. The types of

mechanisms studied include one and two global reaction steps as well as quasi-global

mechanisms. The influences of the various reaction rate parameters on the laminar flame

properties have been identified, and a simple procedure to determine the best values for the

reaction rate parameters is demonstrated. Fuels studied include n-paraffins from methane to

n-decane, some methyl-substituted n-paraffins, acetylene, and representative olefin, alcohol

and aromatic hydrocarbons.

13

Duterque et al, (1981) presented the experimental results of the study, in a “well

stirred reactor”, of the combustion of hydrocarbons with air. The special care had been

given in the realization of a good “stirring”, or homogenization, of the combustor and in the

minimization of heat losses. The experimental results were exploited with a view to leading

to a “quasi global” schematization of the complex chemical processes of combustion, for

which the numerical values of the corresponding constants were obtained. A computer

programme yielded a rather satisfactory agreement with experimental results.

Hutmann et al, (1981) have studied the oxidation of many aliphatic hydrocarbons

(single component) in turbulent flow reactor (developed for kinetic studies) at high

temperature and extensive experimental results were obtained. The results indicated the

viability of presenting this complex kinetic situation in the format of a simplified, overall

kinetic scheme which could accurately predict the major species formed and the

temperature-time history (rate of heat release) of the system.

Cox et. al. (1985) focused on the investigation of the chemistry of knock in internal

combustion engines within the context of a model of auto-ignition of hydrocarbon---air

mixtures at high pressure. The fuel structure dependent parameters were identified and

stability ranking of alkane fuels with respect to auto-ignition was established in this work.

Westbrook (1985) applied the kinetic modeling techniques to two GRI-supported

programs in his work. The computational analysis of laminar flame experiments were

carried out for methane-oxygen-argon flames seeded with NO. Peters (1985) derived short

detailed mechanisms and systematically reduced four-step kinetic mechanisms for

premixed ethylene-air and ethane-air flames, respectively. These mechanisms were

validated by comparison of results obtained with them to results obtained with the full

mechanism and for a wide range of stoichiometries and pressures. The data was analyzed

for flame structures and burning velocities on the basis of short and detailed mechanism.

14

For the range of conditions it was found that the reduced mechanisms predict results that

are in excellent to good agreement with results obtained with the full and the respective

short mechanism.

Glarborg et al, (1986) modeled the experimental data on methane combustion in

stirred reactors. A method to calculate the first-order sensitivities of the mole fractions and

temperature with respect to the rate constants is discussed and applied to nitric oxide

production. In this work, it was pointed that the “Extended Zeldovich” mechanism to be the

major source of NO under lean conditions, while the prompt-NO formation was dominant

under fuel-rich conditions.

The mechanism for methane pyrolysis was generated by Chinnick et al. (1988) and

developed a set of rules associated with each reaction type, for example, decomposition

corresponds to the rupture of every unique single bond in a molecule. In this work it was

concluded that some limitations could be placed on the reactions essentially through a

generalization of the associated rate constants. In his mechanism, all possible reactions

were then constructed, allowing all possible pairs of species to react by all the appropriate

reaction types, including unimolecular processes. The reaction generates two radical

species, and the secondary mechanism includes all possible reactions of these species and

methane, a total of four reactions generating C2H6 and H2. The tertiary mechanism contains

seven reactions and generates two new species; the fourth-order mechanism contains 17

reactions and five new species.

Jones and Lindstedt (1988) developed a global reaction schemes to study the

combustion of hydrocarbons up to butane in premixed and diffusion flames. A generalized

four step reaction mechanism was deuced. The kinetic parameters for the resulting rate

equations were discussed by comparisons with experimental data for premixed methane

and propane flames, along with diffusion flame data for a methane-air flame.

15

Miller and Bowman (1989) discussed the mechanisms and rate parameters for the

gas-phase reactions of nitrogen compounds that are applicable to combustion-generated air

pollution. The results from detailed kinetics calculations were compared with the

experimental data. In this study, the sensitivity & rate-of-production analyses were applied

in the calculations to determine which elementary reactions were of greatest importance in

the nitrogen conversion process. The core areas of uncertainty were outlined in nitrogen

reaction mechanisms and rate parameters.

Smooke et al, (1991) discussed the results of modeling the skeletal methane air

chemistry to sequence of premixed and non premixed flames. In this study, the discussion

focused on the results on adiabatic flame speeds, extinction strain rate, temperature and

species profiles along with the reaction rate data. The results were reported in the

independent spatial coordinates, a normalized spatial coordinate and the mixture fraction.

Warnatz (1992) in his review study described how detailed reaction mechanisms

can be developed for simple hydrocarbons and be verified using literature data on flame

structure, flame propagation, and ignition from the literature. The importance of sensitivity

analysis in the understanding of detailed reaction mechanisms and the identification of rate-

limiting steps is also discussed and suggested for research efforts on this topic.

Peters (1993) outlined the flame calculation using the reduced mechanisms and

presented the reduced mechanism for propane flame and discussed the governing equation

for counter flow diffusion flame

Walker, R. W, and Morley, C, (1997) discussed the basics of combustion chemistry

and discussed the experimental methods to determine the rate of reaction at low and high

temperatures.

16

Anders et al, (1998, 2001) studied a widely used detailed reaction mechanism for

methane oxidation Gas Research Institute (GRI). mechanism 2.11. The mechanism was

transformed to 558 irreversible reactions, and the rate constants were analysed at a fixed

temperature, to reduce the complexity of the analysis. This study described that sensitivity

analysis, principal component analysis of the sensitivity matrix, and rate-of-production

analysis are useful tools in interpreting detailed chemical kinetics calculations

Amano et al, (1998) studied the practical use and communication of the sensitivity

analysis and the related methods. The study also highlighted some limitations of sensitivity

analysis, originating from the mathematical concept (e.g. first-order or brute force

methods) or from the software-specific implementation of the method.

Lester et al, (2000) examined the economic and environmental implications of the

fuels and propulsion technologies that will be available over the next two decades for

powering a large proportion of the light duty fleet (cars and light trucks). The study

described the life cycles of fossil fuels including CNG and highlighted that vehicles should

be redesigned to use the CNG as fuel.

Fournet et al, (2000) presented an automatic method for reducing a detailed primary

mechanism of combustion of any single alkane. Free radicals having the same molecular

formula and the same functional groups are lumped into one single species. The study

concluded that the simulations of lumped and detailed mechanisms of combustion of

isooctane and n-heptane showed a good agreement in a wide temperature range (600–1200

K).

Glaude et al, (2000) analyzed some of the chemical and kinetic principles that rule

the automatic generation of reaction mechanisms by the system EXGAS for the oxidation

of alkanes. The systematic inclusion in the mechanism of all possible reaction pathways, in

comparison with other models published, permits one to discuss the role of the different

17

classes of reactions and to deduce some methods for simplifying a priori these mechanisms

from a kinetic basis. The study validated the simplified mechanisms derived from the

modeling of the oxidation of n-heptane and n-decane.

Huges et al, (2001) developed and tested a comprehensive chemical mechanism to

describe the oxidation of methane consisting of 351 irreversible reactions of 37 species.

The mechanism accounts for the oxidation kinetics of hydrogen, carbon monoxide, ethane,

and ethene in flames and homogeneous ignition systems in a wide concentration range. The

mechanism was tested against a variety of experimental measurements of laminar flame

velocities, laminar flame species profiles, and ignition delay times and compared with the

same reactions in the GRI, Chevalier, and Konnov mechanisms. Similarities and

differences of the four mechanisms are also discussed in this study.

Ellinger et al, (2001) discussed the CO2 Emissions for Internal Combustion Engine

and Fuel Cell Automotive Propulsion Systems. This research work concluded that the

lowest CO2 emissions are produced by CNG vehicles. Smith et al, (2001) developed an

optimized detailed chemical reaction mechanism (GRI-Mech) capable of the best

representation of methane flames and ignition. Tianfeng et al, (2001) studied the method

of computational singular perturbation for the analysis and reduction of complicated

chemical mechanisms was extended to the complex eigen system. In this study, the

comparisons between the reduced and detailed chemistries over a wide range of pressures

and equivalence ratios showed good agreement on the flame speed, flame temperature, and

flame structure. Sung et al, (2001) studied the augmented reduced mechanisms for NO

emission in methane oxidation and previously derived 12-step, 16-species Augmented

Reduced Mechanism (ARM), based on GRI-Mech 1.2, was shown to be comprehensive for

methane oxidation at the levels of global response as well as detailed flame structure.

Subsequently, a 14-step and a 15-step ARMs were derived to account for NO formation.

18

The 14-step ARM was basically the 12-step ARM plus two more steps that respectively

describe the thermal, prompt, and nitrous oxide mechanisms, and the prompt mechanism.

Binita et al, (2003) studied a new optimization-based approach to kinetic model

reduction. The reaction-elimination problem was formulated as a linear integer program. The

method was applied to generate optimally-reduced models for isobaric, adiabatic

homogeneous combustion. The computational cost and accuracy of the reduced models were

compared to those of the full mechanism. Preliminary results are presented comparing the

computational cost of the full GRI Mech. 3.0 chemistry to that of the reduced model library

Mauss F., (2004) reviewed the kinetic mechanism development for combustion

application, automatic mechanism generation and mechanism reduction techniques for their

application to study turbulence in combustion system and other CFD tools.

Tianfeng et al, (2005) also studied a systematic approach for mechanism reduction

was developed and demonstrated. The approach consisted of the generation of skeletal

mechanisms from detailed mechanism using directed relation graph with specified

accuracy requirement, and the subsequent generation of reduced mechanisms from the

skeletal mechanisms using computational singular perturbation based on the assumption of

quasi-steady-state species.

Tianfeng et al, (2006) studied that the conditions for application of the Directed

Relation Graph (DRG) method in skeletal reduction of mechanisms with vastly different

time scales were systematically analyzed. It was found that the existence of quasi-steady

state species induces no additional restriction on the application of DRG. The method of

DRG was then compared with two methods recently developed for skeletal reduction: one

is based on Computational Singular Perturbation (CSP) and another is the Directed

Relation Graph with Error Propagation (DRGEP).

19

Sauro Pierucci and Eliseo Ranzi, (2007) review the features that characterize the

software for the automatic generation of kinetic schemes for hydrocarbons oxidation:

attention was focused on components representation, the list of the elementary reaction

steps as well as the rules to apply them, the algorithm for the homomorphism of molecules,

components and reactions lumping and, finally, a list of kinetic data.

Ridha et al, (2008) tested and compared three chemical kinetic mechanisms of

methane combustion: one-step global reaction mechanism, four-step mechanism, and the

standard detailed scheme GRIMECH 3.0. This study shows good concordances, especially

between the four-step and the detailed mechanisms in the prediction of temperature and

main species profiles. But reduced schemes were incapables to predict pollutant emissions

in an internal combustion engine. The four-step mechanism can only predict CO emissions

but with -out good agreement

J-Y.Chen et al, (2008) described the development of isooctane skeletal mechanisms

for Homogeneous Charge Compression Ignition (HCCI) engines. Two skeletal mechanisms

were constructed: one with 259 species and the other with 291 species. First mechanism

was utilized for accurate predictions of Start of Combustion (SOC) and the 2nd scheme was

aiming at accurate predictions of both SOC and emissions. Both skeletal mechanisms are

found satisfactory in predicting SOC with a speeding up factor of 15/20.

Manshsa, et al, (2010) presented the critical review of literature of development and

application of kinetic reaction mechanisms (model) for various combustion systems. The

authors also presented the chronicle history of computer modules developed for the

automatic generation of reaction schemes.

20

2.4 Summary of Literature Review:

The literature of application of kinetic mechanisms is chronically reviewed in this

chapter. The literature survey indicate that kinetics mechanism were utilized to simulate the

combustion of a number fuels such as methane, ethane, heptane, octane, hydrogen,

hydrogen peroxide etc. The oxidation mechanisms of the these fuels were employed to

study the fluid dynamic aspects such as turbulence, flame development, flame geometry

etc. however, the limited studies exists in which the mechanisms of compressed natural gas

were discussed for the formation of pollutant species in IC engines.

21

CHAPTER-3

Generation of Kinetic Mechanisms of

Natural Gas Combustion

This chapter presents the approach adopted to develop the

reactions mechanisms of natural gas (used as CNG fuel)

using EXGAS (an automatic mechanism generation tool).

An algorithm of coupling two reaction mechanisms is also

discussed. This algorithm is specifically developed for the

present study. The major objective was to develop reaction

mechanisms as well as necessary thermo-chemical data in

a format which is compatible to Chemkin 4.1.1 (a

simulation tool used for further analysis of the mechanisms

in this study). The four different reaction schemes

consisting of various types of reactions feasible under

various combustion conditions in IC engine are also

presented. The detail of kinetic calculations involved is also

discussed in this chapter.

22

3.1 Introduction:

Chemical mechanisms have been used in understanding the hydrocarbon

combustion in terms of the elementary reactions of individual species. The competitive

mechanisms are those which play a more quantitative role and exhibit the closer agreement

with experimental data (both at the macroscopic level and in the simulation of combustion

products, intermediate radical species). The ever more detailed mechanisms are becoming

increasingly feasible and complex because of coincidence with the existence of expanding

databases of rate parameters for elementary reactions. The knowledge gained in

investigating the homogeneous chemical kinetics can be utilized in the reactive flow

conditions found in real combustion in IC engine.

The detailed mechanisms are constructed both manually and automatically (by

computer tools). In manual way of mechanism construction, chemical experts examine the

species likely to be present in the proposed mechanisms, and assess which reactions they

are likely to occur under the appropriate conditions. The computer-based expert systems

present an alternative to the manual mechanism building. In this approach, the rules or

steps, involved in kinetic mechanism generation, are converted into algorithms for

construction of comprehensive kinetic mechanisms. The advantage of the computer- based

approach is that total mechanisms are easily constructed within the confines of the rules.

The procedures can then be readily modified if changes in our understanding lead to a

modification of these rules. Expert systems perform at their best for complex molecules,

such as alkanes, that are degraded via a relatively small set of generic reactions. In current

study, we have been utilized EXGAS computer tool for automatic generation of schemes of

an appropriate detailed mechanism for investigation of natural gas combustion in an

internal combustion engine. The kinetic reaction schemes (generated by EXGAS module

23

contains essential elementary reaction steps initiation, branching, propagation, and

termination etc.) are coupled with nitrogen chemistry.

3.2 Construction of Kinetic Reaction Mechanism:

The reaction mechanism generated by the computer code is composed of following

three components;

(a) C0-C1-C2 reaction base

(b) System generated primary reaction mechanism in which the species in the

initial gas mixture are taken as the reactants.

(c) Secondary mechanism which contains reactions whose reactants are the

molecular products of the primary mechanism.

3.2.1. The C0-C1-C2 Reaction Base:

The reaction base consists of 433 reactions (in which most of the reactions are

reversible) involving 23 free radicals and 18 molecules as reactants. The associated thermo-

chemical and kinetic data were adopted from the literature and were mainly those proposed

by Baulch et al. (1994) and Tsang et al. (1991). This reaction base has uni-molecular, bi-

molecular and tri-molecular elementary type reactions. The reaction base is built using a

reaction grid (as proposed by Tsang et al. (1991) to ensure that it is as comprehensive as

possible.

3.2.2 Representation of Reaction Species:

One dimensional notation (which is non-ambiguous and non-canonical) is utilized

to input the system (computer) compatible chemical formulae of the primary reacting

species. These 1-D notations required to be linked by the system to an internal

representation which permits the reactants & products to be saved in a exclusive format by

using a canonicity algorithm. The symbol “/” represents the single bond and “//” denotes

the double bond. The normal valence number are assumed for the elements such as 4 for

24

Carbon (C), 2 for Oxygen (O), etc., which make the use of implicit chemical bonds. For

example, for normal butane it is denoted by /(CH2/CH3)2, an ethyl radical is denoted by

•CH2/CH3 and oxygen is represented by //(O)2.

3.2.3 Construction of Primary Mechanisms:

a) General Guidelines for Developing Reactions

Walker and Morley (1997) described the rules for constructing reactions and these

rules are currently used to write the kinetic mechanisms for modeling the oxidation of

alkanes. The alkanes having at least three carbon atoms such as propane, the possible

elementary reactions, of the reacting molecules & derived radicals, can be grouped into the

following main seven categories:

a) Uni-molecular and Bimolecular Initiation Reactions

(e.g. C3H8 ↔ •CH3 + •C2H5; C3H8 + O2 ↔ •C3H7 + •OOH),

b) Reactions leading to alkenes from alkyl and hydroperoxyalkyl radicals

• Decompositions by beta-scission

(e.g. •C3H7 ↔ •CH3 + C2H4),

• Oxidations to form the conjugated alkene and •OOH

(e.g. •C3H7 + O2 ↔ C3H6 + •OOH),

c) Additions of alkyl and hydroperoxyalkyl radicals to a molecule of oxygen

(e.g. •C3H7 + O2 ↔ C3H7OO•, •C3H6OOH + O2 ↔ •OOC3H6OOH),

d) Isomerizations of alkyl and peroxy radicals involving cyclic transition state

(e.g. CH3CH2CH2OO• � •CH2CH2CH2OOH),

e) Decompositions of hydroperoxyalkyl and di-hydroperoxyal alkylradicals to form

cyclic ethers, alkenes, aldehydes or ketones (oxohydroperoxyalkanes),

(e.g. •CH2CH2CH2OOH ↔ cyclic-C3H6O + •OH),

(e.g. CH2OOHC•OOHCH3 ↔CH2OOHC(=O)CH3 + •OH),

25

f) Metathesis reactions to abstract an H atom from the initial reactant

(e.g. •OH + C3H8 ↔ H2O + •C3H7),

g) Termination steps:

• Combinations of two free radicals

(e.g. CH3• + CH3• ↔ C2H6),

• Disproportionations of peroxy radicals with •OOH

(e.g. C3H7OO• + •OOH ↔ C3H7OOH + O2).

Figure 3.1 shows the algorithm which is employed to generate primary mechanism ensure

the comprehensiveness of the generated primary mechanism. According to this algorithm, a

free radical •R is created each time in an initiation reaction step; this is systematically

submitted to all the generic propagation reactions as quoted in Figure 3.1. If a new radical

•R* is created, it is also submitted to all the generic propagation reactions. Finally,

termination reactions between all pairs of radicals are taken into account. The systematic

utilization of all generic propagation reactions to each free radical, created either by an

initiation or by a propagation reaction, ensures that the resulting primary mechanism is

comprehensive, at least in the frame of the generic reactions considered in Figure 3.1. This

particular system of automatic mechanism generates a comprehensive reaction schemes for

the reactions subsequent to the second addition of oxygen, leading to hydroperoxy

alkylperoxy radicals •OOQOOH.

Initiation Propagation Termination

Unimolecular reactions Addition to oxygen Combination Bimolecular Reaction Decomposition to cyclo-ether Disproportionation

Oxidations Isomerization

Decomposition by β-scission Metathesis (Alkylic H-atom) Figure 3.1 An Algorithm of Automatic Construction of Primary Mechanisms of

Oxidation of Simple fuels (like Natural gas)

RH •R •R* Primary Products

26

3.2.4. Construction of Secondary Mechanism:

In order to understand the chemistry of the product species produced during the

oxidation of hydrocarbon molecule, it is essential to include a secondary mechanism to the

comprehensive primary mechanism which is discussed in above section. A different

approach is being adopted to avoid an exponential increase of the size of the mechanism

generated and some reduction rules are taken into account without loosing essential

chemical information (For example, kinetic data related to the formation of resonance-

stabilized species from primary products requires to be preserved). The global reactions

which generate the smallest number of steps molecules or radicals are taken into accounts

whose reactions are included in the C0-C1-C2 reaction base. The secondary mechanism is

linked with the C0-C1-C2 reaction base. In addition, the fact that lumped molecules or

radicals are considered makes the notion of a detailed representation of each species

meaningless; thus no reactions of the primary mechanism can be used for these species.

This secondary mechanism is also comprehensive because it is written for each lumped

family of molecules obtained in the primary mechanism. Its general structure is presented

in Figure 3.2.

The general rules being followed in the construction of secondary mechanism by expert

system for automatic generation of reaction mechanism are given below:

a) The degenerate branching reactions occur first by breaking the peroxidic bond in

hydroperoxides, dihydroperoxides, keto-hydroperoxides, aldohydroperoxides and

hydroperoxy-cyclo-ethers produced in the primary mechanism. This unimolecular

decomposition reaction gives an •OH radical and another free radical, which decomposes

into •CH3 or •C2H5 radicals and one or several molecules, whose reactions are included in

the C0-C1-C2 reaction base.

27

b) Cyclic ethers react first by metathesis to give lumped radicals, which can either

decompose or react with oxygen (apart from the case of epoxides). Special care has been

taken to write the secondary mechanism of large ethers deriving directly from reactants,

such oxirans or furans, which are important primary products at low temperatures. The

reactions with oxygen involve the classical sequence of oxygen additions and

isomerizations forming

PRIMARY PRODUCTS 1ST REACTION PRODUCTS SPECIES

Breaking an O-OH bond

H-abstraction

H-abstraction

H addition H-addition

H-abstraction

OOH addition H-abstraction

Figure 3.2 Secondary Mechanisms Generation Rules

ketohydroperoxides which decompose to give •OH and several molecules or radicals

whose reactions are included in the C0-C1-C2 reaction base. These reactions are an

important source of CO2 at low temperatures

Hydro-peroxide Species

Cyclic ethers

Aldehydes

Allylic Radicals reacting by termination

1,3-butadiene

C0-C1 Reaction Base

Alkenes

Epoxides

28

c) For alkanes and alcohols, secondary reactions occur first by metathesis, followed by

subsequent decompositions.

d) Alkenes can react by addition of •H, •OH, •CH3 or •OOH. The addition of •OH is

assumed to produce alcohols or, after beta-scission and isomerization of the enols thus

obtained, aldehydes. Alkenes can also react by metatheses, leading to 1,3-butadiene and

C0-C2 species, when it is possible, or to resonance-stabilized radicals, which are so

unreactive that they can only undergo termination or addition to alkene molecules. These

metathesis reactions are very important, as resonancestabilized radicals (allyl,

methylallyl,..) act by scavenging the reactive free radicals; this could explain some

inhibiting effects observed in oxidation. The terminations involving allylic free radicals

lead to the formation of allylic alkenes, allylic hydroperoxy alkenes and two new types of

molecules, the alcoholic alkenes and the dienes. No specific consumption reactions are

taken into account for these molecules, apart from allylic hydroperoxy alkenes, whose

decomposition has an important kinetic effect. The Diels-Adler reaction of 1,3-butadiene

with ethylene to give cyclohexene can also be considered.

e) The aldehydes can react by metathesis and produce keto free radicals, which will either

decompose to produce CO or add oxygen molecules to form ketoperoxy free radicals.

These latter radicals can isomerize to form ketohydroperoxide alkyl free radicals which

decompose to form CO2. In most cases, the global reactions are written in such a way that

there is no need to consider intermediate free radicals, apart from those included in the C0-

C1-C2 base. The only free radicals containing more than three carbon atoms which are

formed in this secondary mechanism are allylic radicals, keto radicals, ketoperoxy radicals

and those derived from the reactions (i.e. metathesis and subsequent reactions with oxygen)

of oxirans or furans. As these free radicals arise from lumped molecules, their developed

formulae cannot be known; thus, they can only be written in a lumped way.

29

It is worth mentioning that this generation of "secondary" mechanisms is just a first

approach, which certainly needs to be improved to reproduce more satisfactorily the

consumption of the molecules primarily formed.

3.2.5. Choice of reactions to be generated and final mechanism:

Table 3.1 The menu proposed for generating a primary mechanism.

Types of Primary Reactions Possible selection of Options

Unimolecular initiation yes or no

Fate of the radicals obtained by

Uni-molecular initiation

All types of reactions or only reactions

of high temperatures

Bimolecular initiation Yes or no

Addition with oxygen Yes or no

Only one addition or two Yes or no

2nd addition globalized Yes or no

Beta-scission Yes or no

C-H bond breaking Yes or no

C-C bond breaking Yes or no

Isomerizations Yes

Minimum and maximum size of cycle 4, 5, 6 and 6, 7, 8

In the transition state Yes or no

Decomposition to o-ring 3, 4, 5, 6

Cycle size lesser than Yes or no

Oxidation Yes

For all radicals, for beta radicals or for All, beta, beta-mu

Beta-mu radicals Yes or no

with radicals derived from reactants yes or no

Metatheses all, beta, beta-mu

for all radicals, for beta radicals or for

beta-mu radicals

yes or no

30

with .OOR radicals issued from

reactants

yes or no

Combinations all, beta, beta-mu

for all radicals, for beta radicals or for

beta-mu radicals

yes or no

Disproportionations Yes for low temperature

No for high temperature

Table 3.1 shows that it is possible to select those radicals obtained by unimolecular

initiation could react either by all the selected generic reactions (including in some cases by

addition to a molecule of oxygen) or only by reactions of high temperature (i.e.

betascissions and metatheses). It is also possible to define the number of possible additions

to a molecule of oxygen of an alkyl radical (with the second addition globalized or not), the

maximum and minimum sizes of the rings which will be formed in the cyclic transition

states involved in isomerizations, the size of the cyclic ethers which will be formed and the

types of radicals reacting by oxidation, metatheses and combinations according to the rules

defined in section 3.2.3 of this chapter. Oxygen atoms can only react by metatheses.

As the oxidation of the alkyl radicals deriving from the reactant, which are usually

μ free radicals (they can easily decompose in a unimolecular process involving the scission

of a (C-C) bond) are important reactions, it is possible to select that type of radicals to be

considered for oxidations, even when only β and βμ free radicals are taken into account. As

the metatheses of the peroxyalkyl radicals deriving from the reactant, which are usually μ

free radicals (they can easily decompose in a unimolecular process involving the scission of

a (C-C) or (C-O) bond) are important reactions, it is possible to select that type of radicals

to be considered for metatheses, even when only βμ free radicals are taken into account.

To obtain the final mechanism, the reaction base with the associated thermo-chemical and

kinetic data is just added to the file resulting from the generator. In fact, for the consistency

31

of the final mechanism, the following requirements are taken into account during the

automatic generation:

• All the reactions already included in the C0-C1-C2 reaction base are not written again in

the comprehensive primary mechanism generated,

• The metathesis reactions involving free radicals of the reaction base, the termination steps

between the free radicals of the reaction base and those produced by the generator and the

reactions involving two reactants of the reaction base and leading to free radicals or

molecules (containing more than two carbon atoms) produced by the generator are included

if they obey the rules of generation. For instance, the reactions of •OH, •OOH, •CH3 and

•C2H5 are treated according to these rules.

3.3. Thermo-chemical Data Calculation:

The thermo-chemical data for every species involved in the reaction of the

generated mechanism are obtained automatically. This data is the integral part of the

mechanism file, which is stored as fourteen (14) polynomial coefficients. The data

generated in a format compatible with CHEMKIN 4.1.1 used to simulate the combustion in

IC engine. It is important to note that for the lumped molecules (molecules having similar

formulae), thermo-chemical data are those of the first molecules of the category, which

appear during the construction.

3.4 Kinetic Data Calculations:

The rate constant for each reaction is generated automatically and written in the

generated mechanism file. These are either determined for the elementary steps by means

of thermo-chemical kinetic data or estimated by means of correlations.

It is important to note that for the estimation of kinetic data, it is essential to

distinguish the different types of hydrogen atoms which can be abstracted. For example, for

32

alkanes, a single type of H atoms can be abstracted, alkylic H-atoms, which can be primary

(if it is joined to an atom of carbon linked to two other H-atoms), secondary, (when

connected to carbon atom linked to one other H-atom), or tertiary (when connected with

carbon atom linked to no other H-atom).

3.5 Estimation of Kinetic Data by Thermo-chemical Kinetics:

The rate coefficients for the isomerization, the recombinations of free radicals and

the unimolecular decompositions of molecules are calculated using the software (KINGAS)

(Bloch-Michel, 1995) based on the thermo-chemical kinetics methods proposed by Benson

(1976). The activation energies of the bimolecular initiations with oxygen molecules are

also calculated by KINGAS as being equal to the enthalpy of reaction.

a) Isomerization of free radicals

The pre-exponential factors (A) are estimated by using a mean value of 3.5 cal.mol-

1.K-1 for each lost rotor by the following relationship;

(1)

Where

Δni.rot = change in the number of internal notations as reactant to move the transition

state

e =base of natural logarithm, h = plank constant, kB = Boltzman constant, R= gas

constant, rpd = reaction path degeneracy equal to the number of abstractable H-

atom, T = temperature (K).

The activation energies for isomerization reactions are set equal to the sum of the activation

energy for H-abstraction from the substrate by analogous radicals and the strain energy of

the cyclic transition state:

E = Eabst. + Ecycle

33

The values used for these energies are given in Table 3.2. The strain energy of the cyclic

compounds containing zero or one oxygen atom are those proposed by Benson (1976)

while the values for the cyclic compounds containing two oxygen atoms are taken from the

work of the teams of Walker and Pilling (Walker and Morley (1997).

Table 3.2: Calculation of Rate Constants of Free Radicals of Internal

Isomerizations during Automatic Mechanism Generation

A-Activation energy for a H-atom abstraction (Eabst)

Abstracted H atom Primary Secondary Tertiary

Abstraction by ROO* (kcal.mol-1) 21 13 12

Abstraction by *R (kcal.mol-1) 12.5 11.3 8.9 B-Strain energy of cyclic compounds (Ecycle).

Size of the ring 4 5 6 7 8

Rings containing two O atom (kcal.mol-1) 23.2 14.78 8.2 4.9 4.1

Rings containing zero or one O atom (kcal.mol-1) 25.9 6.2 1.1 6.3 9.8

(b) Recombination of free radicals and unimolecular decomposition of molecules

The rate constants for unimolecular decompositions are determined for the reverse

reactions, i.e. recombinations, including thermo-chemical data are obtained with the

THERGAS software. In this software, the activation energies for every recombination

reaction are assumed taken to be zero. For the recombination of two free radicals •R and

•R' to form the molecule RR', the pre-exponential factor A is estimated from the Collision

theory (modified) to be:

With:

R-R' is the Length of the R-R' bond

μ is the reduced molar mass

34

P is the Steric factor, empirically estimated

The value of P is between 0.03 and 1 and varies according to the temperature and the type

of bond created. R is gas consttant, T is temepraure in K.

Table 3.3a Arrhenius (Kinetic) parameters for the oxidation of alkanes of Generated Primary Mechanisms.

Primary H Secondary H Tertiary H Ref. logA b E logA b E LogA b E

Binomolecular initiation 12.84 0 ∆Hr

KINGAS 12.84 0 ∆Hr

KINGAS

12.84 0 ∆Hr

KINGAS

Estimate (Ingham et al. (1994)

Oxidation of an alkyl free radical n>4 11.43 0 5000 11.99 0 5000 11.80 0 5000 Estimate n≤4 11.60 0 5000 12.16 0 5000 11.99 0 5000 Estimate

H-atom abstraction of alkanes by •O• 13.23 0 7850 13.11 0 5200 13.00 0 3280 Chevalier

et al. (1990)

•H 6.98 2 7700 6.65 2 5000 6.62 2 2400 Chevalier et al.

(1990) •OH 5.95 2 450 6.11 2 -770 6.06 2 -1870 Atkinson

(1994) •CH3 -1 4 8200 11.0 0 9600 11.00 0 7900 Chevalier

et al. (1990)

HO2• 11.30 0 17000 11.30 0 15500 12.00 0 14000 Chevalier et al.

(1990) •CHO 4.53 2.5 18500 6.73 1.9 17000 4.53 2.5 13500 Tsang

(1987-90) •CH2OH 1.52 2.95 14000 1.48 2.95 12000 2.08 2.76 10800 Tsang

(1987-90) •OCH3 10.73 0 7300 10.86 0 45000 10.36 0 2900 Tsang

(1987-90) •OOR 12.30 0 20000 12.18 0 17500 12.18 0 15000 Chevalier

et al. (1990)

•C2H5 11.00 0 13500 11.00 0 11000 11.00 0 9200 Estimate i-C3H7• -2.85 4.2 8700 -2.85 4.2 8000 -2.85 4.2 6000 Estimate

•Rp 11.00 0 13500 11.00 0 11200 11.00 0 9000 Ranzi et al. (1994)

•Rs 11.00 0 14500 11.00 0 12200 11.00 0 10000 Ranzi et al. (1994)

•Rt 11.00 0 15000 11.00 0 12700 11.00 0 10500 Ranzi et al. (1994)

Beta-scission 13.00 0 39000 13.18 0 38000 13.18 0 37500 Allara et al. (1980)

Note; Rate constants are expressed in the form k=ATβ exp(-E/RT)

35

Table 3.3b: Kinetic Parameters for other Reactions.

logA b E Ref. Addition of a free radical to O2 Beta-scission of a free radical to

•CH3 + molecule 13.30 0 31000 Estimate •Rp +molecule 13.30 0 28700 Estimate •Rs + molecule 13.30 0 27700 Tsuang (1998)

•Rt + molecule 13.30 0 26700 Chevalier et al. (1990)

Cyclic ether formation cycle with 3 atoms 11.78 0 17950 Estimate (Curran et al.

1998) cycle with 4 atoms 10.96 0 16600 Estimate (Curran et al.

1998)

cycle with 5 atoms 9.56 0 7000 Estimate (Curran et al. 1998)

cycle with 6 atoms 8.23 0 1950 Estimate (Curran et al. 1998)

•OOR and HO2• disproportionation 11.30 0 -1300 Lightfoot et al. (1992)

It is not possible to summarize in a short table the correlations used to estimate the rate

constants of the global reactions of the secondary mechanism. They are estimated as the

rate constants of the first of the elementary steps of these global reactions as follows:

• Rate constants for the decomposition of the hydroperoxides come from Sahetchian et al.

(1992).

For the reactions of alkenes rate coefficients were estimated mostly from the values

proposed by Tsang (1991) for the oxidation of propene; for the addition of •OOH to form

epoxides, they are deduced from Baldwin et al. (1986).

• The rate constants of metathesis reactions for alkanes and alcohols are estimated on the

basis of the same correlations as for metatheses in the primary mechanism. The kinetic

constants for metathesis reactions of aldehydes are from Warnatz (1984) for the reactions

involving •H, from Cavanagh et al. (1990) for the reactions with •O•, •OH, •CH3 and

36

•OOH and from Hohlein (1970) for reactions with •C2H5. Rate constants for metathesis

reactions of •OH and cyclic ethers are those proposed by Atkinson (1994).

By following algorithm rules stated in Figure 3.1 and Figure 3.2 for primary and secondary

reactions and option mentioned in Table 3.1, a number of schemes for C0-C3 hydrocarbons

oxidation were generated and simulated to study combustion of Compressed Natural Gas in

IC engine and investigated the prediction capabilities of each schemes generated. However,

following four schemes with different type of primary and secondary types of reactions at

various temperatures were simulated in this study.

Table 3.4a. Primary Reactions in Different Reaction Mechansims for Natural Gas Oxidation generated by EXGAS

Sr. No Types of Reactions Mechanism-I

Mechanism –II

Mechanism -III

Mechanism -IV

1 Unimolecular initiations √ √ √ √

2 Bimolecular initiations √ √ √ √

3 Additions √ X X X 4 Additions with

oxygen √ X √ X

5 Isomerizations √ √ √ X 6 Decomposition of

OOQOOH into branching agents

√ X √ X

7 Beta-scissions √ √ √ √ 8 Decompositions to

o-rings √ X √ X

9 Oxidations √ √ √ √ 10 Branching √ √ √ √ 11 Metatheses √ √ √ √ 12 Combinations √ √ √ √ 13 Dismutations √ X √ X Table 3.4b. Number of Primary Reactions Considered in Different Reaction

Mechanisms for Natural Gas Oxidation generated by EXGAS Sr. No Types of Reactions Mechanism -

I Mechanism–II

Mechanism -III

Mechanism -IV

1 Unimolecular initiations 1 1 1 1

2 Bimolecular initiations 2 2 2 2

3 Additions 3 X X X

37

4 Additions with oxygen 14 X 10 X

5 Isomerizations 42 1 7 X 6 Decomposition of

OOQOOH into branching agents

18 X 18 X

7 Beta-scissions 30 8 10 5 8 Decompositions to

o-rings 36 X 6 X

9 Oxidations 1 2 2 2 10 Branching 2 2 2 2 11 Metatheses 19 19 23 10 12 Combinations 10 10 10 19 13 Dismutations 4 X 3 X Table 3.4c. Different Primary Molecules Classes in Four Reaction Mechanisms of

Natural Gas Oxidation generated by EXGAS. Sr.No Primary molecules

classes Mechanisms -I Mechanisms -II Mechanisms -III Mechanisms -IV

1 Monohydroperoxides

(ooh)

26 4 6 4

2 Dihydroperoxydes (ooh)2

X X X X

3 O-rings X X X X 4 Allylic molecules

YH 6 3 2 2

5 Alkohols (oh)

5 5 5 5

6 Ethers (o)

1 1 1 1

7 Ketones (co)

10 5 5 5

8 Aldehydes (cho)

11 5 5 5

Each of four kinetic reaction schemes contain Unimolecular initiations, Bimolecular

initiations, Additions, Isomerization, Beta-scissions, Decompositions to o-rings,

Branching, Metatheses, Combination, Dismutation types of primary reactions (Table 3.4a

and Table 3.4b).

38

Also the considered schemes, generated by EXGAS software, contain

Monohydroperoxides (OOH), Dihydroperoxydes (OOH)2, Allylic molecules YH, , Ethers

(O), Ketones (CO), aldehydes (CHO) primary molecules usually present in the combustion

of low hydrocarbons at high temperature (Table 3.4c). The other detail of the developed

reactions is given below;

Mechanism I: A complete mechanism containing all type of reactions Table 3.4a

Mechanism II: A high-temperature mechanism (above 1000 K) neglecting any addition of oxygen;

Mechanism III: A low-temperature mechanism (below 800 K) neglecting beta-

scissions;

Mechanism IV: An intermediate-temperature mechanism neglecting the addition of

oxygen to hydroperoxyalkyl radicals A mechanism obtained by

lumping reactions deriving from the second addition of oxygen.

3.6 Coupling of Hydrocarbon Oxidation and NOx Chemistry:

Four detailed comprehensive kinetic mechanisms for oxidation of CNG combustion

in IC engine were developed by coupling two types of mechanisms; 1) generated by

EXGAS module of NANCY, France and 2) Leed’s NOx Mechanism (Version 2.0).

Mechanism building module of, OpenChem Workbench, an enterprises software suit, was

utilized for coupling these mechanisms. In this module, species/molecule containing file

(NASA formatted) assumed to be present in the chain of reactions in the suggested

mechanism were loaded. Theses molecules were screened by their IUPAC names and

formulas which already exist or connected through online in the database of OpenChem

Workbench. This stage is very critical, if the file is loaded successfully, then save this in

project specified database, otherwise, a conflict/error message will be reported. Then,

revise or modify the original file by removing errors as diagnosed, and loaded it again.

39

Stage-II. When molecule/species file loaded successfully, then import the

mechanism files (generated by EXGAS and Leed’s NOx mechanism file in Chemkin

format). Now activate the Mechanism Building module and uses the information of both

mechanisms loaded and molecular data from saved project database in stage-I. Finally,

export the coupled mechanism file to the system at specified location. Figure 3.3 and 3.4

describe the coupling and development of comprehensive mechanisms for investigation of

natural gas combustion in IC engine. The whole procedure adopted to build four different

kinetic reaction mechanisms.

Import of EXGAS Mechanism File in

Chemkin Format (F3)

NASA Format Molecule File from THERGAS

(F1)

Import of data files

Leeds NOx Molecular data file

(F2)

Build a Coupled Molecule data

Stage-I

If no conflict

Revise F1 & F2

Revised Files

If no any conflict

Import of Leeds NOx Mechansim (Version

2.0) in Chemkin Format (F4)

Building of Coupled Kinetic

Mechanism

Detailed Kinetic Mechanism

CHEMKIN Format

40

Figure 3.3. Algorithm for Coupling of Hydrocarbon Oxidation Mechanism and Nitrogen Oxidation Chemistry.

Figure 3.4. Schematic Diagram of building Chemkin Format Kinetic Mechanisms Through Coupling with OpenChem Workbench. 3.7 Proposed Kinetic Reaction Mechanisms:

Mechanism-I is a comprehensive reaction mechanism containing reactions

feasible at range of temperature conditions (below 800 K and above 1000 K). This

mechanism is composed of 935 elementary reactions and 185 species. Mechanism-II is a

high temperature (above 1000 K) reaction mechanism and consists of 124 species and 792

elementary reactions. This mechanism composed of that type of reaction feasibly at high

Reactants (C0-C4)

Reactions and Arhenius

Kinetic data file

EXGAS

KINGASTHRGAS

NASA Thermo formatted file

Hydrocarbon Oxidation Mechanism Generation

Leed’s NOx Mechanism (Version 2.0) Thermodynamic

data file

Chemkin-IV Format Kinetic Mechanism File OpenChem Workbench

Mechanism Building Module

NOx Chemistry Coupling of EXGAS andNOx Mechanisms Files Output Files

41

temperature during the combustion of natural gas. Mechanism-III is a low temperature

(below 800 K) reaction mechanism and consists of 152 species and 864 elementary

reaction. Mechanism-IV is developed by the simplification of Mechanism-I by the

chemical lumping technique. By this technique, reaction steps with similar reactants and

products have been eliminated. This reaction model is consisting of only 72 species and

208 elementary reactions. The proposed reaction mechanisms were used to simulate the

combustion of natural gas under various temperature conditions and to predict the

emissions.

Detail of these reaction models (mechanisms) is given in Annexure-I showing the

Arrhenius parameters. The related thermodynamic data required to simulate the combustion

in IC engine is given in Annexure-II.

Some important reacting species and radicals presents in these above mentioned reaction

mechanisms (models) are given in Table 3.5.

Table 3.5. Intermediate and Product Species and Radicals in Each Kinetic Mechanism

Sr. No

Mechanism Name

Number of Species

Product and Intermediate (Species/Radicals)

1 Mechanism-I (Complete Mechanism )

185

B1O,B2CO,B3C, B4CH, B5CH2,B6CH2,H2, H2O,O2, H2O2, CH4, HCHO, CH3OH, CO2, CH3OOH, C2H2T, C2H4Z, C2H6, CH2COZ, CH3CHO, C2H5OH, C2H5OOH, CH3COOOH, C3H6Y, C3H8, C4H8Y , C4H10 C2H5CHO C3H7OH C2H6CO C3H8CO C4H6Z2 C2H3CHOZ C3H7CHO C3H5OOHZ C2H4CHOOOH C4H7OOHZ C3H6CHOOOH C3H5OOHY C2H5COOOH C4H7OOHY C3H7COOOH C3H7OOH C4H9OH C4H10O C4H10OO C5H12 C6H14 C4H9OOH C3H5OHY C3H5CHOY C4H7OHY C4H8OOY C5H10Y C6H10Y2 C7H12Y2 C4H7CHOY C5H9OHY C5H10OOY C6H12Y C8H14Y2 C2H4O#3 C3H6O#3 C3H6O#4 C4H8O#3 C4H8O#4 C4H8O#5 C3H5O#3OOH C3H5O#4OOH C4H7O#3OOH C4H7O#4OOH C4H7O#5OOH C6H10Z#6 R1H R2OH R3OOH R4CH3 R5CHO R6CH2OH R7CH3O R8CH3OO R9C2HT R10C2H3V R11C2H5 R12CHCOV R13CH2CHO R14CH3CO R15C2H5O R16C2H4OOH R17C2H5OO R18CH3COOO R19C3H7 R20C4H9 R21C3H7 R22C3H7OO R23C4H9OO R24C3H7OO R25C3H6OOH R26C3H6OOH R27C4H8OOH R28C4H8OOH R29C4H8OOH R30C3H6OOH R31C3H6OOOOH R32C3H6OOOOH R33C4H8OOOOH R34C4H8OOOOH R35C4H8OOOOH R36C4H8OOH R37C3H6OOOOH R38C3H5O4H2 R39C3H5O4H2 R40C3H5O4H2 R41C3H5O4H2 R42C4H7O4H2 R43C4H8OOOOH R44C4H7O4H2 R45C4H7O4H2 R46C4H7O4H2 R47C4H7O4H2 R48C4H7O4H2 R49C4H8OOOOH R50C4H7O4H2 R51C4H7O4H2 R52C4H8OOOOH R53C3H5O4H2 R54C4H7O4H2 R55C4H8OOH R56C4H7O4H2 R57C4H8OOH R58C4H7O4H2 R59C4H7O4H2 R60C4H7O4H2 R61C4H9OO R62C4H7O4H2 R63C4H8OOH R64C4H9 R65C4H8OOOOH R66C4H7O4H2 R67C4H7O4H2 .C3H5Y .C4H7Y .COC2H5 .COC2H3Z .COC3H7 .COOOC2H5 .COOOC3H7 C2H2 CO CH2O C H CH CH2 CH2(S) CH3 C2H3 H2CCCH O OH HO2 HCO HCCO N2 AR CN HCN N NH NO HNO NH2 H2NO NCO N2O NO2 N2H2 HOCN H2CN NNH NH3 N2H3 C2N2 HNCO HE

2 Mechanism-II (High Temperature, above 1000 K) 124

B1O B2CO B3C B4CH B5CH2 B6CH2 H2O O2 H2O2 CH4 HCHO CH3OH CO2CH3OOH C2H2T C2H4Z C2H6CH2COZ CH3CHOC2H5OH C2H5OOH CH3COOOH C3H6Y C3H8 C4H8Y C4H10 C2H5, CHO C3H7OH, C2H6CO C3H8CO C4H6Z2, C2H3CHOZ C3H7OOH C3H7CHO C4H9OH C4H10O C4H10OO C5H12 C6H14 C3H5OHY C3H5OOHY C3H5CHOY C4H7OHY C4H8OOY C5H10Y C6H10Y2 C7H12Y2 C4H7OOHY C4H7CHOY C5H9OHY C5H10OOY. C6H12Y C8H14Y2 C2H4O#3. C3H6O#3 C4H8O#3. C6H10Z#6. R1H R2OH R3OOH R4CH3 R5CHO R6CH2OH. R7CH3O R8CH3OO R9C2HT R10C2H3V R11C2H5 R12CHCO. R13CH2CHO. R14CH3CO R15C2H5O R16C2H4OOH R17C2H5OO R18CH3COOO R19C3H7 R20C4H9 R21C3H7 R22C4H9 .C3H5Y .C4H7Y .COC2H5 .COC2H3Z .COC3H7 .COOOC2H5 .COOOC3H7 CH2O C H CH CH2 CH2(S) CH3 C2H3 H2CCCH O OH HO2 HCO HCCO N2 AR CN HCN N NH. NO HNO NH2 H2NO NCO N2O NO2 N2H2 HOCN H2CN NNH. NH3. N2H3. C2N2 HNCO HE

42

3 Mechanism-IIII (Low Temperature, Below, 800 K)

152

B1O B2CO B3C B4CH B5CH2 B6CH2 H2 H2O O2 H2O2. CH4 HCHO CH3OH CO2. CH3OOH. C2H2T C2H4Z CH2COZ CH3CHO C2H5OH C2H5OOH CH3COOOH C3H6Y C3H8. C4H8Y C4H10 C2H5CHO C3H7OH C2H6CO C3H8CO C4H6Z2C2H3CHOZ C2H5COOOH C3H7COOOH C3H7OOH C3H7CHO C4H9OH C4H10O C4H10OO C5H12 C6H14 C4H9OOH C3H5OHY C3H5OOHY C3H5CHOY C4H7OHY C4H8OOY C5H10Y C6H10Y2 C7H12Y2 C4H7OOHY C4H7CHOY C5H9OHY C5H10OOY C6H12Y C8H14Y2 C2H4O#3 C3H6O#3 C3H6O#4 C4H8O#3 C4H8O#4 C4H8O#5 C6H10Z#6 C2H3O#4COOOH R1H R2OH R3OOH R4CH3 R5CHO R6CH2OH R7CH3O R8CH3OO R9C2HT R10C2H3V R11C2H5 R12CHCOV R13CH2CHO R14CH3CO R15C2H5O R16C2H4OOH R17C2H5OO R18CH3COOO R19C3H7 R20C4H9 R21C3H7 R22C3H7OO R23C4H9OO R24C3H7OO R25C3H6OOH R26C3H6OOH R27C4H8OOH R28C4H8OOH R29C4H8OOH R30C3H6OOH R31C3H6OOOOH R32C3H6OOOOH R33C4H8OOOOH R34C4H8OOOOH R35C4H8OOOOH R36C4H8OOH R37C3H6OOOOH R38C4H8OOOOH .C3H5Y .C4H7Y .COC2H5 .COC2H3Z .COC3H7 .COOOC2H5 .COOOC3H7 .C3H5O#4 .OOC3H5O#4 .C3H4O#4OOH .OOC3H4O#4OOH C2H2 CO CH2O C H CH CH2 CH2(S) CH3 C2H3 H2CCCH O OH HO2 HCO HCCO N2 AR CN HCN N NH. NO HNO NH2 H2NO NCO N2O NO2. N2H2. HOCN H2CN NNH NH3 N2H3 C2N2 HNCO HE

4 Mechanism-IV 72

B1O H2 H2O O2 H2O2 CH4 HCHO CH3OH CO2 CH3OOH C2H4Z C2H6 C3H6Y C3H8 C4H8Y C4H10 C3H7OH C3H7OOH C3H7CHO C4H9OH C4H10O C4H10OO C5H12. C6H14 R1H R2OH R3OOH R4CH3 R5CHO R6CH2OH R7CH3O R8CH3OO R11C2H5 R19C3H7 R20C4H9 R21C3H7 C2H2 CO CH2O C H CH CH2 CH2(S) CH3 C2H3 H2CCCH O OH HO2 HCO HCCO N2 CN HCN N NH NO HNO NH2 H2NO NCO N2O NO2 N2H2 HOCN H2CN NNH NH3 N2H3 C2N2 HNCO

3.8 Summary:

Four kinetic reaction mechanisms were developed to simulate the combustion of

natural gas in an automobile engine. These reaction mechanisms were generated by

coupling of two reaction mechanisms (i) EXGAS reaction mechanisms and (ii) Leeds NOx

mechanism. The essential associated thermo-chemical data (in NASA format) of each

species in each of the mechanism was also generated. Mechanism-I is consisting of 935

reactions steps and 185 species while mechanism-II; It is a high temperature (above 1000

K) reaction mechanism consisting of 124 species and 792 elementary reactions this

mechanism composed of those type of reaction feasibly at high temperature during the

combustion. Mechanism-III is a low temperature (below 800 K) reaction mechanism

consisting of 152 species and 864 elementary reaction and Mechanism-IV is consisting of

only 72 species and 208 elementary reactions. The proposed reaction mechanisms are

implemented in IC engine module of Chemkin 4.1.1 to simulate the combustion natural gas

for the prediction of formation of pollutants.

43

CHAPTER-4 Parametric Analysis of Proposed

Kinetic Mechanisms of CNG

Combustion

In this chapter, the simulation of natural gas combustion in

IC engine using four detailed kinetic mechanisms

(discussed in Chapter 3). These mechanisms are

implemented in Chamkin 4.1.1 to investigate the effect of

various operating parameters such as engine speed, fuel to

air equivalence ratio etc on the in-cylinder temperature,

pressure and pollutants formation profiles. At the end of

this chapter, parametric uncertainty analysis of each

mechanism was carried out to estimate the contribution of

uncertainty of each operating parametric in the prediction

of concentration of pollutant species. Based upon the

simulation results and discrepancies among the each

simulated profile, an appropriate mechanism among the

proposed reaction models is predicted.

44

4.1 Introduction: An Internal Combustion (IC) engine cylinder is a type of 0-D homogeneous reactor

system under auto-ignition conditions. The reacting mixture in the combustion chamber is

treated as a closed system (Figure 4.1) with no mass crossing the boundary, so the total

mass of the mixture m =Σk=1 mk is constant, and dm/dt = 0: Here mk is the mass of the kth

species and K is the total number of species in the mixture. The individual species are

produced or destroyed according to;

kkdtdm WVk

•

= ω (1)

Where k=1, 2, 3, ……K

Where t is time, ώk is the molar production rate of the kth species by elementary reaction,

Wk is the molecular weight of the kth species, and V is the volume of the system, which

varies through combustion cycle.

Figure 4.1 Conceptual 0-D homogeneous reactor system of Engine Combustion Chamber (adopted from Heywood, 1988).

The reactants species (Fuel and oxidizer) undergoes thousands of reversible or irreversible

chemical reactions (elementary or non elementary) during combustion in the engine

cylinder. Generally, the elementary reversible (or irreversible) reactions involving K

chemical species in combustion chamber of IC engine can be represented in the general

form as;

45

(5) The stoichiometric coefficients are integer numbers and are the chemical symbol for the kth

species. The superscript indicates forward stoichiometric coefficients, which indicates

reverse stoichiometric coefficients. Normally, an elementary reaction involves only three or

four species; hence the matrix is quite sparse for a large set of reactions.

The production rate of the kth species can be written as a summation of the rate of-progress

variables for all reactions involving the kth species

(6)

Where

(7) The rate of progress variable for the ith reaction is given by the difference of the forward

and reverse rates as

(8) Where Xk is the molar concentration of the kth species and kfi and kri are the forward and

reverse rate constants of the ith reaction. As indicated in Equation 6, the rate-of-progress of

a reaction is determined using the concentration of each reactant or product species raised

to the power of its stoichiometric coefficient. Equation 6 is also applicable for mass-action

kinetics and when mechanism is written in terms of elementary reactions.

The forward rate constants for the reactions are generally assumed to have the following

Arrhenius temperature dependence:

(9)

46

Where the pre-exponential factor, the temperature exponent, and the activation energy are

specified. These three parameters are required input to the GAS-PHASE KINETICS

package for each reaction. In thermal systems, the reverse rate constants are related to the

forward rate constants through the equilibrium constants by

(10)

Although is given in concentration units, the equilibrium constants are more easily

determined from the thermodynamic properties in pressure units; they are related

(11)

The conservation of mass and species (Fuel and Oxidizer) homogeneous system include

net generation of chemical species within the reactor volume, and net loss of species

and mass to surfaces in the reactor.

4.2 Simulation of Combustion in IC Engine by Chemkin 4.1.1:

CHEMKIN is a powerful set of software tools for solving complex chemical

kinetics problems. It is used to study reacting flows, such as those found in combustion,

catalysis, chemical vapour deposition, and plasma etching. CHEMKIN consists of rigorous

gas-phase and gas-surface chemical kinetics in a variety of reactor models that can be used

to represent the specific set of systems of interest.

The IC model is for 0-D closed system, the simulation is only valid within the time

period when both intake and exhaust valves are closed. Conventionally, engine cylinder

events are expressed in crank rotation angle relative to the Top Dead Center (TDC). The

Intake Valve Close (IVC) time of our test engine is -142 degrees (crank angle) before TDC.

47

4.3 Operating Variables Combustion in Automobiles Engines:

The major operating variables that affect combustion kinetics in an automobiles

combustion chamber and emission efficiency are engine speed, fuel/air ratio relative to the

stoichiometric ratio, engine load and spark timing. In present study, we have investigated

the effect of fuel/air equivalence ratio, engine speed, initial inlet temperature of

combustible mixture (CNG-Air) and engine compression ratio.

4.4 Objectives:

The objective of the parametric investigation of each of the proposed mechanism is to;

• Simulate of the effect of various input operating variables (equivalence ratio, speed,

Inlet gas composition, Initial Pressure, Temperature, etc) to study combustion of

Compressed Natural Gas (CNG) using developed kinetic mechanisms.

• Predict the profiles of emission CO, NO, NO2 and NH3

• Selection of an appropriate and representative kinetic mechanism.

4.5 Simulation of Effect of Operating Variables in CNG fired IC Engine:

4.5.1 General Simulation Inputs;

General inputs of the simulation are:

Chemical reaction mechanisms with Arrhenius Coefficients,

Thermodynamic data,

Molar fractions of reactive species (Natural Gas: CH4, C2H6,C3H8, and air –

O2, N2) for various equivalence ratios and

Geometrical parameters of the IC Engine (cylinder displaced volume,

clearance volume, crank to connecting rod ratio etc.).

48

Table 4.1 Typical Engine Geometrical Input Parameters and Initial Gas (Feed) Mixture Composition

Sr. No

Engine Geometrical Input Parameters Initial Gas Mixture (CNG composition), Mole Fraction

Parameter (unit) Value Component Mole Fraction

1 Cylinder volume (cm3) 63 Methane (CH4) 0.8903 2 Displaced Volume (cm3) 56.52 Ethane (C2H6) 0.0105

3 Clearance Volume (cm3) 6.48 Propane (C3H8) 0.027

4 Cylinder Diameters (cm) 14.67 Butane (C4H10) 0.0017

5 Crank to Connecting rod ratio 1.632 Nitrogen (N2) 0.072

6. Combustion Starting Crank Angle

-142° Carbon Dioxide (CO2)

0.026

The following outputs were from the simulation studies;

Temperatures profiles

Pressures profiles

Main species profiles

Total rate-of-production and

Peak of temperature for various excess air ratios.

The combustion characteristics of fuel-air mixture and properties of combustion product

correlate best for wide range of fuel composition to the stoichiometric mixture proportions.

Therefore equivalence ratio is considered as performance defining parameter of an

automobile engine. For best engine performance, fuel/air ratio is adjusted for maximum

output power and in current strict environmental restriction on the vehicular emissions, this

parameter is again very important which greatly affect the emission levels in the engine

exhaust. The simulation conditions for investigation of the effect of various variables are

given in Table 4.2a to Table 4.2d.

49

Table 4.2a Input Operating Parameters to Study the Effect of Equivalence Ratio for Four Kinetic Mechanisms

TYPICAL INPUT PARAMETERS Run # Equivalence

Ratio (φ) Compression

Ratio (γ) Engine Speed

(rpm) Initial

Temperature (K) Initial Pressure

(atm) Run-I 0.6 10.5 3000 300 0.67 Run-II 0.86 10.5 3000 300 0.67 Run-III 1.0 10.5 3000 300 0.67 Run-IV 1. 3 10.5 3000 300 0.67 Run-V 1.4 10.5 3000 300 0.67

Table 4.2b Input Operating Parameters to Study the Effect of Compression

Ratio for Four Kinetic Mechanisms TYPICAL INPUT PARAMETERS Run # Equivalence

Ratio (φ) Compression

Ratio (γ) Engine Speed

(rpm) Initial

Temperature (K), Initial Pressure

(atm) Run-I 1.0 10.51 3000 300 0.67

Run-II 1.0 8.0 3000 300 0.67 Run-III 1.0 9.5 3000 300 0.67 Run-IV 1.0 11.0 3000 300 0.67

Table 4.2c Input Operating Parameters to Study the Effect of Engine Speed for

Four Kinetic Mechanisms TYPICAL INPUT PARAMETERS Run # Equivalence

Ratio (φ) Compression

Ratio (γ) Engine Speed

(rpm) Initial

Temperature (K), Initial Pressure

(atm) Run-I 0.6 10.5 2000 300 0.67 Run-II 0.86 10.5 1500 300 0.67 Run-III 1.0 10.5 3000 300 0.67 Run-IV 1. 3 10.5 5000 300 0.67 Run-V 1.4 10.5 7000 300 0.67

Table 4.2d.Typical Input Operating Parameters to Study the Effect of Initial Inlet Temperature for Four Kinetic Mechanisms

TYPICAL INPUT PARAMETERS Run # Equivalence

Ratio (φ) Compression

Ratio (γ) Engine Speed

(rpm) Initial

Temperature (K), Initial Pressure

(atm) Run-I 0.6 10.5 3000 1200 0.67

Run-II 0.86 10.5 3000 1500 0.67 Run-III 1.0 10.5 3000 2300 0.67 Run-IV 1. 3 10.5 3000 3100 0.67 Run-V 1.4 10.5 3000 4000 0.67

50

These variables directly affect the output of the engine measurable parameters like engine

cylinder pressure, temperature and other combustion products including emissions of

various pollutants. The affect of the variation of these input variables are simulated for

natural gas with composition given in Table 4.1 using IC engine modules of Chamkin

4.1.1. The variable input windows of IC engine reactor module of Chemkin are shown in

Figure 2a.

51

Figure 4.2a Parameter Input Windows for (A) Reactor Physical Properties (B) Reactant Species

A

B

52

4.6 Results and Discussion:

4.6.1 Adiabatic Flame Temperature:

The adiabatic flame temperature is a measure of the maximum temperature that

could be reached by combusting a particular gas mixture under a specific set of conditions.

The maximum temperature reached in combustion chamber of an IC engine is estimated by

determining the adiabatic flame temperature of input fuel-air mixture in as;

Net heat of reactions =Q= (ΣNihi)prod-( ΣNihi)react (11)

For adiabatic process conditions, put Q=0 in above equation;

Q= (ΣNihi)prod-( ΣNihi)react=0 (12)

where:

Ni = number of moles of component i

hi = (h'j)i + ∂hi

h'f = enthalpy of formation, the enthalpy needed to form one mole of that

component at standard conditions of 25°C and 1 atm

∂hi = change of enthalpy from standard temperature for component i

The THERGAS module in the format compatible to the Chemkin 4.1.1 software

determined the enthalpy data of the species in the reaction mechanism.

The solution of the above equation gives equilibrium temperature of the product gas

mixture, which is the maximum temperature of the hot gases produced as result of

combustion under adiabatic process conditions. So this equilibrium temperature represents

the adiabatic flame temperature of CNG-Air combustion mixture using four proposed

mechanisms in the IC (automobile engine). The species produced by simulating the

combustion of CNG in IC engine using four reaction mechanisms are given in Table 3.5 of

Chapter 3. The equilibrium calculations of temperature of these product mixture were

53

calculated by solving above equations (11) to equation (12) at constant pressure and

enthalpy with initial temperature (200 K) and pressure (1.0 atm) under stoichiomteric

conditions (φ=1.0). In these calculations, an estimated solution temperature of 9,000 K is

used to ensure that the solution obtained is for an ignited gas.

Figure 4.2 illustrates that the calculated equilibrium temperatures of product mixtures

formed during the combustion using four proposed reaction mechanisms.

Figure 4.2 Equilibrium Product Temperatures (Adiabatic Flame Temperature) of CNG-Air Mixture in IC Engine at constant pressure and enthalpy.

Initial Temperature_(K)

Adi

abat

ic F

lam

e Te

mpe

ratu

re_(

K)

320 330 340 350 360 370 380 390 400 410 420 4308230

8235

8240

8245

8250

8255

8260

8265

8270

8275

8280

8285

Mechansim-IV

Initial Temperature_(K),

Adi

abat

ic F

lam

e Te

mpe

ratu

re_(

K)

320 330 340 350 360 370 380 390 400 410 420 4306230

6235

6240

6245

6250

6255

6260

6265

6270

6275

6280

6285

Mechansim-III

Initial Temperature_(K),

Adi

abat

ic F

lam

e Te

mpe

ratu

re_(

K)

320 330 340 350 360 370 380 390 400 410 420 4306335

6340

6345

6350

6355

6360

6365

6370

6375

6380

6385

6390

Mechansim-I

Initial Temperature_(K),

Adi

abat

ic F

lam

e Te

mpe

ratu

re_(

K)

320 330 340 350 360 370 380 390 400 410 420 4304410

4415

4420

4425

4430

4435

4440

4445

4450

4455

4460

4465

Mechansim-II

54

The temperatures are on the order of ~6300 K, 4400 K, 6200 K and 8200 K for

Mechanism-I, Mechanism-II, Mechanism-III and Mechanism-IV respectively corresponds

to the burned gas mixture. It is also from the plots for each mechanism that clear adiabatic

flame temperatures increase with increasing initial gas temperature.

The actual peak temperature in an engine cycle will be several hundred degrees less than

this. There is some heat loss even in the very short time of one cycle, combustion

efficiency is less than 100% so a small amount of fuel does not get burned, and some

components dissociate at the high engine temperatures. All these factors contribute to

making the actual peak engine temperature somewhat less than adiabatic flame

temperature.

4.6.2. In-Cylinder Temperature and Pressure Profiles:

Table 4.3a to 4.6d shows the peak temperature obtained by simulating combustion

on IC engine for proposed combustion mechanisms for the simulation condition given

Table

Table 4.3a Predicted Peak Combustion Temperatures and Pressure (Mechanism-I)

Run # Equivalence Ratio (φ)

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 0.6 3533.07 2787.14 31.06 8.27 Run #2 0.8 3384.09 2650.25 28.37 7.55 Run #3 1.0 3497.30 2753.77 39.80 8.06 Run #4 1.3 3656.63 2808.46 40.76 8.45 Run #5 1.4 3572.40 2783.11 32.87 8.68

Table 4.3b Predicted Peak Combustion Temperatures and Pressure at Various

Compression Ratios (Mechanism-I)

Run # Compression Ratio

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 10.5 4554.738 3861.653 39.776 9.860 Run #2 8.0 4317.696 3828.634 27.014 8.393 Run #3 9.5 4403.759 3849.79 32.830 9.287 Run #4 11.0 4478.655 3867.056 38.749 10.134

55

Table 4.3c Predicted Peak Combustion Temperature and Pressure at Various Inlet

Temperatures (Mechanism-I) Run # Engine

Operating Speed (rpm)

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 2000 4149.564 3410.652 37.262 12.701 Run #2 1500 4152.437 3522.028 37.566 12.631 Run #3 3000 4242.703 3329.309 39.476 13.426 Run #4 5000 4141.208 3315.369 36.370 10.551 Run #5 7000 4150.400 3349.637 37.245 11.334

Table 4.3d Predicted Peak Combustion Temperature and Pressure at Various Inlet

Temperatures (Mechanism-I) Run # Initial Inlet

Temperature, K

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 1200 4256.909 3411.758 39.499 12.768 Run #2 1500 3924.661 3115.511 36.270 11.920 Run #3 2300 4074.898 3572.558 33.252 11.700 Run #4 3100 4106.12 3866.434 35.814 9.782Run # 5 4000 4194.356 4090.233 31.088 8.536

Table 4.4a Predicted Peak Combustion Temperatures and Pressure (Mechanism-II)

Run # Equivalence Ratio (φ)

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 0.6 3533.077 2787.147 31.057 8.271 Run #2 0.8 3384.09 2650.257 28.368 7.548 Run #3 1.0 3497.303 2753.777 30.304 8.061 Run #4 1. 3 3686.634 2808.468 32.963 8.450 Run #5 1.4 3572.402 2783.114 32.872 8.684

Table 4.4b Predicted Peak Combustion Temperature and Pressure at Various

Compression Ratios (Mechanism-II)

Run # Compression Ratio

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 10.5 4394.422 3611.282 38.371 10.634 Run #2 8.0 4044.691 3580.096 26.548 8.182 Run #3 9.5 4137.722 3599.887 32.389 9.073 Run #4 11.0 4221.446 3616.544 36.384 9.917

56

Table 4.4c Predicted Peak Combustion Temperature and Pressure at Various Engine Operating Speeds (Mechanism-II) Run # Engine

Operating Speed (rpm)

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 2000 3558.158 2833.125 31.030 9.709 Run #2 1500 3520.781 2898.45 30.233 10.715 Run #3 3000 3507.646 2811.808 29.541 7.199 Run #4 5000 3495.64 2812.203 29.293 7.188 Run #5 7000 3495.904 2851.535 29.618 7.724

Table 4.4d Predicted Peak Combustion Temperature and Pressure at Various Inlet

Temperatures (Mechanism-II) Run # Initial Inlet

Temperature, K

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 1000 3535.111 2790.405 31.099 6.285 Run #2 1500 4660.129 3138.658 23.934 8.532 Run #3 2300 3834.282 3317.204 17.989 4.893 Run #4 3100 4030.068 3484.754 15.092 4.091 Run #5 4000 4283.087 3660.009 13.597 3.638

Table 4.5a Predicted Peak Combustion Temperatures and Pressure (Mechanism-III) Run # Equivalence

Ratio (φ) Temperature, K Pressure, atm

Peak Mean Peak Mean Run #1 0.6 3496.176 2721.555 29.669 8.204 Run #2 0.8 3350.21 2626.129 27.151 7.583 Run #3 1.0 3462.595 2691.484 28.900 8.015 Run #4 1. 3 3516.907 2736.116 30.309 8.387 Run #5 1.4 3526.161 2722.499 31.276 8.613

Table 4.5b Predicted Peak Combustion Temperature and Pressure at Various Compression Ratios (Mechanism-III)

Run # Compression Ratio

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 10.5 4294.331 3611.255 38.365 10.828 Run #2 8.0 4044.619 3580.073 26.538 8.326 Run #3 9.5 4137.638 3599.862 32.356 9.237 Run #4 11.0 4221.35 3616.517 39.394 9.108

57

Table 4.5c Predicted Peak Combustion Temperature and Pressure at Various Engine Operating Speeds (Mechanism-III)

Run # Engine Operating

Speed (rpm)

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 2000 2929.211 2161.77 4.231 2.338 Run #2 1500 3507.841 2605.803 29.543 8.493 Run #3 3000 3495.869 2740.922 29.185 10.216 Run #4 5000 3496.144 2721.521 29.677 8.214 Run #5 7000 3036.960 2279.958 6.460 2.998

Table 4.5d Predicted Peak Combustion Temperature and Pressure at Various Inlet Temperatures (Mechanism-III)

Run # Initial Inlet Temperature,

K

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 1200 3740.574 3056.131 44.490 10.442 Run #2 1500 3813.799 3137.954 45.631 11.600 Run #3 2300 4718.691 3340.577 48.012 18.750 Run #4 3100 4242.419 3522.667 35.408 7.324 Run #5 4000 4520.406 3703.807 41.911 16.524

Table 4.6a Predicted Peak Combustion Temperature and Pressure (Mechanism-IV) Run # Equivalence

Ratio (φ) Temperature, K Pressure, atm

Peak Mean Peak Mean Run #1 0.6 3938.445 2887.321 35.104 12.687 Run #2 0.8 3237.007 2397.719 35.495 9.291 Run #3 1.0 3743.27 2741.147 39.722 11.877 Run #4 1. 3 4277.804 3033.155 41.845 14.413 Run #5 1.4 4158.05 3108.919 40.655 13.989

Table 4.6b Predicted Peak Combustion Temperature and Pressure at Various Compression Ratios (Mechanism-IV)

Table 4.6c Predicted Peak Combustion Temperature and Pressure at Various Engine Operating Speeds (Mechanism-IV)

Run # Engine Operating

Speed (rpm)

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 2000 3969.016 3079.702 35.636 16.093

Run # Compression Ratio

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 10.5 4321.005 3405.452 40.224 13.649 Run #2 8.0 4063.117 3369.407 34.540 10.699 Run #3 9.5 4162.341 3392.536 36.086 11.889 Run #4 11.0 4248.506 3411.321 39.828 13.019

58

Run #2 1500 3010.293 2718.889 39.733 10.180 Run #3 3000 4058.016 3043.345 40.777 14.830 Run #4 5000 3939.693 2890.19 44.219 10.940 Run #5 7000 3939.045 2904.444 45.168 14.148

Table 4.6d Predicted Peak Combustion Temperature and Pressure at Various Inlet

Temperatures (Mechanism-IV) Run # Initial Inlet

Temperature, K

Temperature, K Pressure, atm Peak Mean Peak Mean

Run #1 1000 3938.445 2927.054 39.104 13.789 Run #2 1500 3544.514 2453.489 38.622 14.061 Run #3 2300 3286.971 3551.213 35.567 11.921 Run #4 3100 3559.296 3984.856 36.405 9.694 Run #5 4000 3765.221 4305.729 37.873 8.309

The peak cylinder temperature and pressure data (given in Table 4.3a to 4.6d) was

determined during the investigation of effect of various variable like Fuel/Air equivalence

ratio (φ), compression ratio (γ), engine speed (rpm) and initial inlet temperature (K).

Mechanism-I :( Complete Mechanism containing elementary reactions at low and high

temperature as given in Table 3.4a -3.4c of Chapter-3). The peak temperature varied from

3384.09 K (when φ=0.8) to 3656.63 K (when φ=1.3) if we varied the Fuel/Air equivalence

ratio from 0.6 (Lean fuel conditions) to 1.4 (Fuel rich conditions). While peak cylinder

pressure varied from 28.37 atm (when φ=0.8) to 33.76 atm (when φ=1.3). The highest

peak cylinder temperature and pressure was 4554.738 K and 39.776 atm was observed

when compression ratio was 10.51. The compression ratio was varied from 8.0 to 11.0. So,

the maximum temperature and pressure would if achieved if combustion chamber would be

designed for compression ratio of 10.5. In this study other input parameters were kept

constants as given in Table 4.2b. The cylinder pressure and temperature varied from

4317.696 K (γ=8.0) to 4554.738 K (γ=10.5) and 27.01462 (γ=8.0) atm to 39.776 atm

(γ=10.5) respectively. The effect of engine speed on the peak combustion pressure and

temperature in the engine cylinder was simulated using the input parameters given in the

59

Table 4.2c where engine speed was varied from 1500 rpm (low speed) to 7000 rpm

(highest speed). These are the speed limits selected as the tested engine can achieved these

speeds when it was operating without load. The maximum peak cylinder temperature

(4242.703 K) and pressure (38.47675 atm) was achieved when engine speed was 3000 rpm

while other input parameters were kept fixed as given in Table 4.2c. The cylinder pressure

and temperature were varied from 4141.4 K- 424.703 K and 10.552-13.42615 atm

respectively over the selected range of engine operating speed. There was little variation in

the peak temperature with the variation in the engine speed while pressure varies

significantly. The initial inlet temperature effect the initiation of the combustion (oxidation)

of the reactant mixture. In the simulation software, (i.e, Chemkin 4.1.1), this temperature

indicate the minimum temperature showing the success of the simulations run. The

minimum initial inlet temperature of the mixture is the 1200 K for Mechanism-I. This

variable was varied from 1200 K to 4000 K. The data given in the Table 4.3d indicates that

the maximum peak temperature was achieved at 1200 K. The increase in the initial inlet

temperature, there is little variation in the peak temperature and peak cylinder pressure

sowing the decreasing trend.

If we simulate the combustion pressure and temperature in the natural gas (with the

composition give in the Table 4.2) fired IC engine by Mechanism-I, the maximum peak

temperature and pressure can be achieved at equivalence ratio of 1.3 (under fuel rich

operation), compression ratio of 10.5 (design value for the tested engine), about 3000 rpm

engine speed and when initial inlet temperature was kept at 1200 K.

Mechanism-II; (High Temperature, above 1000 K). The simulation study of natural gas

combustion with high temperature kinetic reaction scheme (Mechanism-II) was carried

with the input variables Fuel/Air Ratio, Compression Ratio, Engine Operating Speed and

Initial Inlet temperature given in Table 4.2a to 4.2d respectively. Each variable was varied

60

while other are kept constant with values determined by experimental investigation of CNG

fired automobile engine. The peak cylinder temperature and pressure of 3686.634 K and

32.963 atm was achieved for Fuel/air equivalence ratio of 1.3 when engine performance

was simulated for various equivalence ratio varied from fuel lean conditions (φ=0.6,

φ=0.86) to fuel rich conditions (φ=1.3, φ=1.4) and stoichiomteric operating conditions.

The maximum peak temperature and pressure was obtained for fuel rich conditions.

When test were conducted to simulate the effect of compression ratio (γ) on the

chamber pressure and temperature with Mechanism-II, the maximum peak temperature and

pressure were 4394.422 K and 38.371 atm respectively for compression ratio of 10.51. For

these tests, other simulation conditions were kept as given in Table 4.2b. The study of

effect of engine operating speed was on combustion of natural gas with Mechanism-II

indicating that the 3558.158 K and 31.0307 atm were maximum peak cylinder temperature

and pressure respectively were achieved when engine speed was 2000 rpm. The engine

speed was varied from 1500 rpm to 7000 rpm while other input parameters were kept

constant. The simulation of initial inlet temperature (varied from 1000 K to 4000 K)

indicate that maximum peak temperature (4660.129 K) and pressure (23.93402 atm) was

reached at 1500 K.

When combustion in IC engine was simulated with kinetic Mechanism-II (High

temperature mechanism), the maximum peak temperature and pressure was achieved at

equivalence ratio of 1.3, compression ratio of 10.51, and low engine speed of about 2000

rpm and initial inlet temperature of 1500 K.

Mechanism-III; (Low temperature kinetic mechanism, below 800 K); when this

mechanism was loaded in Chemkin 4.1.1 to simulate the effect of various engine operating

variables as discussed above, the results of peak cylinder temperature and pressure are

given in Table 4.5a to 4.5d. Table 4.5a shows that the peak temperature (3526.161 K) and

61

pressure (31.27 atm) at equivalence ratio of 1.4 (under fuel rich conditions) was achieved

when equivalence ratio (Fuel/air) varied from 0.6 to 1.4. These simulation tests were

conducted using input variables as given in Table 4.2a. When input variables used as given

in Table 4.2b, the compression ratio was varied from 8.0 to 11.0. These studies produced

the maximum peak temperature of 4294.331 K and maximum peak pressure of 38.364 atm

at compression ratio of 10.51. Now to simulate effect of engine speed on the engine

performance when combustion was simulated with kinetic Mechanism-III, the engine speed

was varied from 1500 rpm to 7000 rpm as given in Table 4.2c. The maximum peak

temperature and pressure were at 1500 rpm as given in Table 4.5c. The data given in Table

4.5d shows that with mechanism, the maximum peak temperature (4718.691 K) and

pressure (48.01 atm) in engine cylinder was achieved when initial inlet temperature was

about 2300 K

These studies illustrated that the maximum peak temperature and pressure in IC

engine combustion chamber was achieved at equivalence ratio of 1.4, compression ratio of

10.51, engine speed of 1500 rpm (low speed) and at initial inlet temperature of 2300 K

Mechanism-IV; This mechanism contains of unimolecular initiations, bimolecular

initiations, beta-scissions, oxidations, branching, metatheses, and combinations types of

reactions both low and high temperature reactions. The simulation results are given in

Table 4.6a to 4.6d. The variation in the cylinder temperature and pressure with change in

fuel/air equivalence ratio (0.6 to 1.4) is given in Table 4.6a. The maximum peak

temperature (4277.804 K) and pressure (41.84569 atm) was obtained with the equivalence

ratio of ≈1.3. During the compression ratio tests, the peak temperature and pressure of

4321.005 K and 40.224 atm respectively was achieved at 10.51. The compression ratio was

varied from γ=8.0 to γ=11.0 while other input parameters are kept fixed as given in Table

4.2c. Table 6c shows the simulation results of effect of engine operating speed (varied

62

from 1500 rpm to 7000 rpm). The peak cylinder pressure and temperature of 40.77 atm and

4058.016 K respectively at engine speed of about ≈3000 rpm. The other input variables

used are given in Table 4.2c. The data given in Table 6d shows the maximum peak

temperature and pressure were 3938.445 K and 39.104 atm respectively at initial inlet

temperature of about ≈1000 K.

This simulation study of natural gas (major contents are given in Table 4.1)

combustion with kinetic Mechanism (models)-IV shows that the maximum peak

temperature and pressure was achieved when equivalence ratio (Fuel/air) was ≈1.3,

compression ratio of ≈10.51, engine speed of ≈ 3000 rpm and initial inlet temperature of

≈1000 K.

Figures 4.3a to 4.3d show the variation in peak pressure and temperature in the

combustion chamber of the IC engine with given specification in Table 4.1. This variation

is shown by the Whisker-Box-plots which presented a good comparison of effect of fuel/air

equivalence ratio, compression ratio, engine speed and initial inlet temperature. According

to these plots, maximum variation exits in the peak temperature and pressure for

Mechanism-IV with change of equivalence ratio and initial inlet temperature as shown in

Figure 3a and Figure 3d respectively. The effect of compression ratio and engine speed on

cylinder temperature and pressure was significantly observed with Mechanism-III.

63

Figure 4.3a Variation in Peak Cylinder Pressure and Temperature at Various

Equivalence Ratios

Proposed Kinetic Reaction Schemes

Peak

Cyl

inde

r Tem

pera

ture

,K

Mechansim-I Mechanism-II Mechansim-III Mechanis-IV3200

3300

3400

3500

3600

3700

3800

3900

4000

4100

4200

MaximumMinimum75%25%MedianOutliersExtremes

Propsed Kinetic Reaction Schemes

Peak

Cyl

inde

r Pre

ssur

e, a

tm

Mechansim-I Mechanism-II Mechansim-III Mechanis-IV27

28.5

30

31.5

33

34.5

36

37.5

39

40.5

42

MaximumMinimum75%25%MedianOutliersExtremes

64

Figure 4.3b Variation in Peak Cylinder Pressure and Temperature at Various

Compression Ratios

Proposed Kinetic Reaction Schemes

Peak

Cyl

inde

r Tem

pera

ture

, K

Mechansim-I Mechanism-II Mechansim-III Mechanis-IV4020

4080

4140

4200

4260

4320

4380

4440

4500

4560

MaximumMinimum75%25%MedianOutliersExtremes

Proposed Kinetic Reaction Schemes

Peak

Cyl

inde

r Pre

ssur

e, a

tm

Mechansim-I Mechanism-II Mechansim-III Mechanis-IV25.5

27

28.5

30

31.5

33

34.5

36

37.5

39

40.5

MaximumMinimum75%25%MedianOutliersExtremes

65

Figure 4.3c Variation in Peak Cylinder Pressure and Temperature at Various

Engine Operating Speeds

Propsed Kinetic Reaction Schemes

Peak

Cyl

inde

r Tem

pera

ture

, K

Mechansim-I Mechanism-II Mechansim-III Mechanis-IV2850

3000

3150

3300

3450

3600

3750

3900

4050

4200

4350

MaximumMinimum75%25%MedianOutliersExtremes

Propsed Kinetic Reaction Schemes

Peak

Cyl

inde

r Pre

ssur

e, a

tm

Mechansim-I Mechanism-II Mechansim-III Mechanis-IV0

5

10

15

20

25

30

35

40

45

50MaximumMinimum75%25%MedianOutliersExtremes

66

Figure 4.3d Variation in Peak Cylinder Pressure and Temperature at Various

Initial Inlet Temperatures. Although the four proposed mechanisms show the successful simulation of natural gas

combustion with little variation the input variables as discussed above for equivalence

Proposed Kinetic Reaction Schemes

Peak

Cyl

inde

r Pre

ssur

e, a

tm

Mechansim-I Mechanism-II Mechansim-III Mechanis-IV10

15

20

25

30

35

40

45

50

55

60

MaximumMinimum75%25%MedianOutliersExtremes

Proposed Kinetic Reaction Schemes

Peak

Cyl

inde

r Tem

pera

ture

, K

Mechansim-I Mechanism-II Mechansim-III Mechanis-IV3450

3600

3750

3900

4050

4200

4350

4500

4650

4800

MaximumMinimum75%25%MedianOutliersExtremes

67

ratio, compression ratio, engine speed and initial inlet temperature. There were some major

discrepancies observed during these simulation studies. Figure 4.4 and Figure 4.5 shows

the combustion chamber (cylinder) pressure and temperature profiles respectively when

simulation was carried at 3000 rpm, stoichiometric equivalence ratio ≈1.0, and

compression ratio of 10.51 for four proposed kinetic mechanisms. The pressure profiles for

Mechanism-II (High temperature mechanism) and Mechanism-III (Low temperature

mechanism) multiple spikes in the curves which indicate multiple charge of fuel and

combustion process occur during very short duration of complete engine cycle (4-strokes).

Each spike in the profiles indicates the occurrence of reactions under the selected

simulation conditions. The combustion reactions occur three times when combustion is

simulated with Mechanism-II and Mechanism-III and each of the profiles shows the early

start of combustion during the complete engine cycle (-150° to 150°). The first combustion

cycle occur near -120° of the crank position angle.

The experimental data do not support this kind of the occurring of the reactions in

the combustion chamber of the IC engine. This argument let down the mechanisms

containing the only high temperature or only low temperature with unpredictable

simulation results simulation data.

The pressure and temperature profile obtained with Mechanism-I show the uneven

behavior of variation under the selected simulation conditions. The trend of the curves

shows the abnormal combustion reaction occurrence which indicates the knocking

phenomena. Both profiles of temperature and pressure depicts that the mechanism contains

some elementary reactions making this mechanism as the representative of natural gas

combustion mechanism in IC engine and is unable to predict the true picture of the process.

68

Figure 4.4 Pressure Profiles of IC Engine Cylinder operating at 3000 rpm, φ=1.0 for

Combustion Simulation with Four Kinetic Relation Mechanism

Crank rotation angle

Pred

icte

d C

ylin

der P

ress

ure,

atm

-150 -120 -90 -60 -30 0 30 60 90 120 1500

5

10

15

20

25

30

35

40

Mechansim-IV

Crank rotation angle

Pred

icte

d C

ylin

der P

ress

ure,

atm

-150 -120 -90 -60 -30 0 30 60 90 120 1500

3

6

9

12

15

18

21

24

27

30

Mechanism-II

Crank rotation angle

Pred

icte

d C

ylin

der P

ress

ure,

atm

-150 -120 -90 -60 -30 0 30 60 90 120 1500

5

10

15

20

25

30

35

40

45

Mechansim-III

Crank rotation angle

Pred

icte

d C

ylin

der P

ress

ure,

atm

-150 -120 -90 -60 -30 0 30 60 90 120 1500

5

10

15

20

25

30

35

40

45

Mechanism-I

69

Figure 4.5 Temperature Profiles of IC Engine Cylinder operating at 3000 rpm, φ=1.0 for Combustion Simulation with Four Kinetic Relation Mechanism

If we examine the pressure and temperature profiles obtained by simulating the combustion

of natural gas in IC engine module of the Chemkin 4.1.1 with Mechanism-IV, it is clear

that the pressure profile is almost is a smooth curves which indicate the normal combustion

occurrence in the combustion chamber of IC engine with given specification in Table 4.1.

The maximum peak cylinder pressure and temperature reached at -2.68° crank angle

Crank rotation angle

Pred

icte

d C

ylin

der T

empe

ratu

re,K

-150 -120 -90 -60 -30 0 30 60 90 120 1501200

1400

1600

1800

2000

2200

2400

2600

2800

3000

3200

3400

3600

Mechansim-II

Crank rotation angle

Pred

icte

d C

ylin

der T

empe

ratu

re,K

-150 -120 -90 -60 -30 0 30 60 90 120 1501600

1800

2000

2200

2400

2600

2800

3000

3200

3400

3600

3800

Mechansim-III

Crank rotation angle

Pred

icte

d C

ylin

der T

empe

ratu

re,K

-150 -120 -90 -60 -30 0 30 60 90 120 1501250

1500

1750

2000

2250

2500

2750

3000

3250

3500

3750

4000

Mechanism-IV

Crank rotation angle

Pred

icte

d C

ylin

der T

empe

ratu

re, K

-150 -120 -90 -60 -30 0 30 60 90 120 1501200

1500

1800

2100

2400

2700

3000

3300

3600

3900

4200

Mechanism-I

70

position. The trend of both profiles of Mechanism-IV indicates that this mechanism consist

of the reactions which would be representative of the combustion of natural gas. Further,

the experimental data of measured cylinder pressure and temperature also shows the similar

trend.

Figure 4.6 to 4.7 shows the predicted profiles for formation of major combustion products

i.e.CO2 and H2O for four proposed kinetic mechanisms. These profiles indicate the results

of in-cylinder formation of CO2 and H2O when engine with given engine specification

along with fuel gas composition as given in Table 4.1 operated at about 3000 rpm with

initial inlet pressure of 067 atm, initial inlet temperature of 1500 K and Fuel/Air

equivalence ratio of about ≈ 1.0 (under stoichiometric conditions). According to CO2

profiles (Figure 4.6), both low and high temperature mechanisms (Mechanism-II and

Mechanism-III) predicted the early start of combustion and curves show the unpredictable

pattern throughput the engine cycle. High temperature mechanism (Mechanism-II) profile

cyclic pattern of formation and consumption of CO2 while low temperature mechanism

profiles show the formation of CO2 initially during the compression stroke and later on

during combustion stroke. Both mechanisms (low and high temperature) predictions do not

agree with the experimental observations.

The CO2 profiles for Mechanism-I and Mechanism-IV predict the start of combustion at

2.68° of crank angle position. Initial profiles shows closer behavior but later during the end

of combustion and blow down to exhaust processes, curves shows deviations. In spite of

the other reasons, this indicate that at the start and during the combustion process, both

mechanisms contains the similar types of reaction contribute the formation of CO2 and late

on during the exhaust and power stroke, different type of reaction occurring.

71

Figure 4.6 Predicted CO2 profiles in IC Engine Cylinder at 3000 rpm, 0.67 atm, 1500 C and φ ≈1.0.

Crank rotation angle

Mol

e Fr

actio

n, C

O2

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

0.055

0.06

0.065

0.07

0.075

0.08

0.085Mechansim-IMechansim-IIMechansim-IIIMechansim-IV

72

Figure 4.7 Predicted H2O profiles in IC Engine Cylinder at 3000 rpm, 0.67 atm, 1500 °C and φ ≈1.0.

The types of reactions present in both of mechanisms which contribute the formation and

consumption of CO2 are disused in Chapter-6 of the Rate of Production Analysis (ROP).

Similar pattern of formation and consumption of H2O during this simulation is

shown in Figure 4.7. Mechanism-II and Mechanism-III shows the early start of the

combustion while mechanism-I and Mechanism-IV shows the start of combustion at the

acceptable crank angle position during the engine cycle.

Crank rotation angle

Mol

e Fr

actio

n, H

2O

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16Mechansim-IMechansim-IIMechansim-IIIMechansim-IV

73

Figure 4.8 Variation in Peak CO2 Mole Fractions in IC Engine simulated for four proposed Kinetic Mechanisms at various (A) equivalence ratios, (B) Speeds, (C) Initial Inlet Temperatures and (D) Compression Ratios

AB

CD

Mechansim

Mol

e Fr

actio

n, C

O2

Mechanism-I Mechanism-II Mechanism-III Mechanism-IV0.035

0.04

0.045

0.05

0.055

0.06

0.065

0.07

0.075

0.08

0.085

0.09

MaximumMinimum75%25%MedianOutliersExtremes

Mechansim

Mol

e Fr

actio

n, C

O2

Mechanism-I Mechanism-II Mechanism-III Mechanism-IV0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

0.055

0.06

MaximumMinimum75%25%MedianOutliersExtremes

Mechanism

Mol

e Fr

actio

n, C

O2

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0.008

0.016

0.024

0.032

0.04

0.048

0.056

0.064

0.072

0.08

0.088

MaximumMinimum75%25%MedianOutliersExtremes

Mechanism

Mol

e Fr

actio

n, C

O2

Mechasism-I Mechasism-II Mechasism-III Mechasism-IV0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

0.02

0.022

MaximumMinimum75%25%MedianOutliersExtremes

74

Figure 4.9 Variation in Peak H2O Mole Fractions in IC Engine simulated for four proposed Kinetic Mechanisms at various (A) Equivalence Ratios, (B) Speeds, (C) Initial Inlet Temperatures and (D) Compression Ratios

The variation in peak CO2 and H2O molar fractions with various operating parameters like

Fuel/Air equivalence ratio, engine speed and initial inlet temperature, etc is plotted in Box-

and-Whisker plots as shown in Figure 4.8 to 4.9, respectively. These plots show the

variation in 25-75 % data sets, medians, range (Mini-Max values). Both figures show that

Mechansim

Mol

e Fr

actio

n, H

2O

Mechanism-I Mechanism-II Mechanism-III Mechanism-IV0.075

0.09

0.105

0.12

0.135

0.15

0.165

0.18

0.195

MaximumMinimum75%25%MedianOutliersExtremes

Mol

e Fr

actio

n, H

2O

Mechanism-I Mechanism-II Mechanism-III Mechanism-IV0.112

0.116

0.12

0.124

0.128

0.132

0.136

0.14

0.144

0.148

0.152

0.156

MaximumMinimum75%25%MedianOutliersExtremes

Mechansim

Mol

e Fr

actio

n, H

2O

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0.03

0.045

0.06

0.075

0.09

0.105

0.12

0.135

0.15

0.165

0.18

MaximumMinimum75%25%MedianOutliersExtremes

Mechanism

Mol

e Fr

actio

n, H

2O

Mechasism-I Mechasism-II Mechasism-III Mechasism-IV0.064

0.068

0.072

0.076

0.08

0.084

0.088

0.092

0.096

0.1

0.104

MaximumMinimum75%25%MedianOutliersExtremes

A B

CD

75

equivalence ratio and initial inlet temperature significantly affect the peaks concentrations

of major combustion products, i.e. CO2 and H2O. The compression ratio has least effect of

the CO2 and H2O peak molar fractions. The engine speed shows the effect for the

Mechanism-IV which support the argument that Mechanism-IV is closer to real

combustion mechanism.

4.7 Formation of Pollutant Species:

Ideally, it is desired that very few harmful emissions are to be generated from the

fuel and engines and should be exhausted to the surroundings without a major impact on

the environment. The undesirable emissions, generated in the combustion process of

automobile and other IC engines, pollute the environment and contribute to global

warming, acid rain, smog, odors, and respiratory and other health problems. The emissions

of concern are carbon monoxide (CO), oxides of nitrogen (NOx), hydrocarbons (HCs), and

particulates. The major causes of these emissions are non-stoichiometric combustion,

dissociation of nitrogen, and impurities in the fuel and air.

In this study I investigated the formation mechanisms of nitrogen containing pollutants

such as nitric oxide (NO), nitrogen dioxide (NO2) & ammonia (NH3) and carbon monoxide

(CO) in CNG fired automobile engine.

4.7.1 Formation of Nitrogen Containing Pollutants (NO, NO2 and NH3):

The chemical reactions of nitrogen compounds that occur in combustion chamber of

IC engine of intensive interest for understanding the formation of nitrogen containing

compounds. The term NOx, (nitrogen oxides) refers to the summation of all oxides of

nitrogen but when it is described as pollutants then nitric oxide (NO) and nitrogen dioxide

(NO2) are the most important.

76

The four kinetic mechanisms of natural gas combustion in an IC engine were studied using

input conditions as given in Table 4.1 and Table 4.2. During this combustion simulation

studies, a number of nitrogen containing compounds such as, CN, HCN, N, NH, NO,

HNO, NH2, NCO, N2O, NO, NO2, NH3, N2H2, HOCN, NNH, etc were formed. In this

study, formation of NO, NO2 and NH3 compounds in IC engine are of prime concern.

Figure 10 shows the profiles of nitric oxide (NO) formed due to natural gas combustion in

an automobiles engine with specification as given in Table 4.1. Each profile illustrate the

results of formation of NO with four kinetic mechanisms simulation at equivalence ratio

≈1.0, engine speed ≈ 3000 rpm, initial inlet temperature ≈1500 K and initial inlet pressure

≈0.67 atm.

The NO molar fraction data was plotted against crank position angle for each mechanism.

Each profile showed the discrepancies in the formation reactions. NO profiles of high and

low temperature mechanisms (Mechanism-II & Mechanism-III) shows the incomparable

and unpredictable pattern while complete and simplified mechanism with medium

temperature ranges (1000-2000 K) mechanisms (Mechanism-I & Mechanism-IV). Also, the

Mechanism-II & Mechanism-III indicate the early start of formation reactions NO with the

selected simulation conditions.

77

Figure 4.10 Nitric Oxide (NO) profiles at Equivalence ratio ≈ 1.0, engine speed ≈ 3000 rpm, Tini =1500 °C and Pini=0.67 atm

The Mechanism-I and Mechanism-IV showed the start of NO formation nearly at -7.18° of

crank position angle and peak molar fractions reached at nearly 2.68° of crank position

angle at the end of the combustion process.

The peak molar fractions of NO concentrations in the combustion products obtained with

study of effect of Fuel/air equivalence ratio, engine speed, initial inlet temperature and

Table 4.7a Peak Concentrations (Mole Fraction) of NO at Various Equivalence ratios for Four Kinetic Mechanisms

Equivalence Ratio Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

0.6 0.063 0.019 0.010 0.049 0.8 0.184 0.051 0.018 0.197 1 0.101 0.043 0.014 0.089

1.3 0.026 0.015 0.007 0.016 1.4 0.047 0.059 0.021 0.023

Crank rotation angle

Mol

e Fr

actio

n, N

O

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

0.055

0.06

0.065

0.07

0.075

0.08

0.085

Mechansim-IMechansim-IIMechanism-IIIMechanism-IV

78

Table 4.7b Peak Concentrations (Mole Fraction) of NO at Various Engine Speeds for Four Kinetic Mechanisms

Engine Speed Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

2000 0.0492 0.019 0.0092 0.0456 1500 0.0501 0.019 0.0183 0.0502 3000 0.0513 0.0187 0.0135 0.0843 5000 0.0523 0.0182 0.0184 0.0753 7000 0.0522 0.0131 0.0114 0.0491

Table 4.7c Peak Concentrations (Mole Fraction) of NO at Various Initial Inlet

Temperatures for Four Kinetic Mechanisms Initial Temp (K) Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

1200 0.0498 0.0194 0.0185 0.0462 1500 0.0335 0.0208 0.0108 0.0613 2300 0.0242 0.0215 0.0165 0.0297 3100 0.0318 0.0208 0.0198 0.0371 4000 0.0379 0.0188 0.0206 0.0437

Table 4.7d Peak Concentrations (Mole Fraction) of NO at Various Compression

Ratios for Four Kinetic Mechanisms Compression

Ratio Mechanism-I Mechanism-II Mechanism-III Mechanism-IV 10.51 0.0412 0.0246 0.0276 0.0503

8 0.0276 0.0227 0.0227 0.0321 9.5 0.0286 0.0233 0.0233 0.0384 11 0.0495 0.0238 0.0238 0.0462

compression ratio is given in Table 4.7a to Table 4.7d respectively. The peak molar

fractions were achieved by each mechanism as 0.1846, 0.0512, 0.0189 and 0.1973

respectively at equivalence ratio of 0.86. The maximum peak molar fractions of 0.0523,

0.0188, 0.0187, 0.0843 at 5000 rpm, 2000 rpm, 1500 rpm and 3000 rpm respectively.

79

Figure 4.11 Variation in Peak Molar fractions of NO formation in IC engine for Four

Kinetic Mechanisms at Various (A) Equivalence Ratios (B) Engine Speed, (C) Initial Inlet Temperature and (D) Compression Ratios

The maximum peak NO molar of 0.0613 was achieved by the Mechanism-IV at initial inlet

temperature of 1500 K. At compression ratio of 10.51, the maximum peak NO molar

Mechanisms

Mol

e Fr

actio

n, N

O

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

MaximumMinimum75%25%MedianOutliersExtremes

Mechansims

Mol

e Fr

actio

n, N

O

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

0.11

MaximumMinimum75%25%MedianOutliersExtremes

Mechansims

Mol

e Fr

actio

n, N

O

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0.006

0.012

0.018

0.024

0.03

0.036

0.042

0.048

0.054

0.06

0.066

MaximumMinimum75%25%MedianOutliersExtremes

Mechanism

Mol

e Fr

actio

n, N

O

Mechasism-I Mechasism-II Mechasism-III Mechasism-IV0

0.003

0.006

0.009

0.012

0.015

0.018

0.021

0.024

0.027

0.03

MaximumMinimum75%25%MedianOutliersExtremes

A B

C D

80

fraction of was achieved for each mechanism but the maximum peak value of 0.0503 was

obtained with Mechanism-IV. The effect of equivalence ratio, engine speed, initial inlet

temperature and compression ratio on NO formation profiles with each reaction scheme

was studied with inputs as give in Table 4.2a to Table 4.2d. The significant effect of

equivalence ratio, engine speed and initial inlet temperature was observed especially in the

peak NO molar fractions in combustion process between -10° to 8° crank position angle for

Mechanism-I and Mechanism-IV. The variation in peak NO molar fractions due to various

input IC engine operating variables is shown in Figure 11.

Nitric oxide forms throughout the high-temperature burned gases through chemical

reactions involving nitrogen and oxygen. Various types of common reactions identified by

the rate of production analysis. The most important reactions formed NO in combustion

processes;

• Thermal-NO Formation Reactions

• Prompt-NO Formation Reactions

• Fuel-NO Formation Reactions and

• Nitrous oxide N2O Formation Reactions.

These mechanisms are given in Figure 4.12 and rate parameters of these reaction is given

in Table 4.10. For fuel-NO mechanism, natural gas contains nitrogen, and some of this

nitrogen forms the fuel-NO. In case of prompt-NO mechanism, the principal source of

thermal nitric oxide, NO is the oxidation of atmospheric molecular nitrogen, N2. The

formation of NO exceeds that attributable to thermal-NO. Such prompt-NO comes from

chemical pathways of NO2 and N2O reactions (Table 4.10), or in rich fuel flames, where

NO is formed by the hydrogen radical-molecular nitrogen reaction. Generally the

combustion of near stoichiometric fuel-air mixtures, the principal reactions governing the

formation of NO from molecular nitrogen are:

81

O+N2 = NO+N

N+O2 = NO+O

N + OH = NO + H

This mechanism is particularly simple because N atoms are the only N-containing

intermediate in this mechanism.

The kinetic reactions involved in the developed four kinetic mechanisms for

formation and oxidation of NO, NO2 and N2O are as follows;

(i) Nitric oxide, NO reactions (Thermal and prompt NO). The important thermal-NO

(equilibrium) formation reactions are R4, R20 and R32 in Table 4.10. These reactions are

also important in super-equilibrium conditions. NO is produced mainly by the thermal

mechanism and the higher pressures. A certain amount of nitric oxide is produced by the

"prompt-NO route”. Here carbon containing free radicals reacts with molecular nitrogen to

form nitric oxide by reactions, which probably involve reactions such as (Table 4.10);

R-9 O2+CN=NCO+O

R-13 HO+CH=CHO+H

R-25 NO+CH2(S) = HCN+OH

R-39 NO+NCO=N2O+CO

R-80 HCN+O=CN+OH

R-81 HCN+OH=CN+H2O

R-133 OH+CN=NCO+H

R-135 OH+NCO=NO+CO+H

R-164 N2+CH=HCN+N

(ii) Nitrogen dioxide, NO2 reactions. The important reactions for formation and oxidation

of NO2 are (Table 10);

R-28 NO+HO2=NO2+OH

82

R-54 N2O+O=NO+NO

R-165 N2O+O=NO2+N2

Reactions R28 and R-53 are the principal reactions for formation of NO2. The principal

removal step for NO2 and prompt formation of NO is reaction;

R-54 N2O+O=N2+O2

(iii) Nitrous oxide, N2O reactions. The important reactions for formation and oxidation of

N20 are reactions;

R-52 N2O+H=N2+OH

R-53 N2O+O=N2+O2

R-165 N2O+O=NO2+N2

The principal reaction for N2O formation is the third body reaction, R-165. The principal

removal steps of N2O and prompt formation of NO from N2O are reactions, R-54 and R-52.

The NO formation reactions with mechanisms is shown more elaborately by the tree

diagram as shown in Figure 4.12.

83

Figure 4.12. Reactions Involved in NO Formation in IC engine NO2 Formation;

The simulation studies indicate that nitrogen dioxide (NO2) is formed. The nitrogen

dioxide formed during the combustion of natural gas in IC engine. The simulation results of

molar fraction of NO2 plotted versus crank rotation angle for the four kinetic reaction

mechanism schemes discussed in Chapter-3.

84

Figure 4.13. Nitrogen Dioxide (NO2) profiles at Equivalence ratio ≈ 1.0, engine speed ≈ 3000 rpm, Tini =1500 K and Pini=0.67 atm

Simulation with Mechanism-II and Mechanism-III produced the un-predictable behavior

during the complete engine cycle and the mechanism-IV predicted the closer practical

behavior as shown in Figure 4.13. The major reason of the discrepancies among the NO2

profiles is dictated by the types of reaction and reaction conditions. Following are the

involved reaction in the formation and consumption of NO2 during the combustion of

natural gas with the proposed mechanisms.

R-28 NO+HO2<=>NO2+OH

R-43 NO2+O<=>NO+O2

R-47 NO2+NH<=>N2O+OH

R-48 NO2+NH2<=>N2O+H2O

R-50 NO2+M NO+O+M

Crank rotation angle

Mol

e fr

actio

n, N

O2

(Sca

le fo

r Mec

hans

im-I

& M

echa

nsim

-III)

Mol

e fr

actio

n, N

O2

(Sca

le fo

r Mec

hans

im-i&

Mec

hans

im-IV

)

-150 -120 -90 -60 -30 0 30 60 90 120 1500 0

2E-7 3E-6

4E-7 6E-6

6E-7 9E-6

8E-7 1.2E-5

1E-6 1.5E-5

1.2E-6 1.8E-5

1.4E-6 2.1E-5

Mechansim-IMechansim-IIMechanism-IIIMechanism-IV

85

In these reactions, R-50 is most promising to contribute in the formation of NO2 and

R-48 is the reaction which significantly contributes in the consumption of the NO2. The

peak concentration observed during the simulation to study the effect of various input

parameters is given in Table 4.8a to Table 4.8d. These simulation results indicate the peak

molar fractions obtained at the equivalence ratio of 0.8, engine speed of about 3000 rpm

and initial inlet temperature of about 1500 K. The peaks molar fractions were observed at

various crank ration angles during the engine cycle but the peak molar fractions with

Mechanism-IV were between swept of 20° of duration of crank rotation angle as clear from

Figure 4.10 of NO2 profiles with four mechanisms.

Figure 4.14 shows the effect of input parameters (Fuel/Air equivalence ratio, engine

speed, initial inlet temperature and compression ratio). The effect of these parameters is

plotted by the Box-and-Whisker plots. According to these plots, equivalence ratio, engine

speed and initial inlet temperature significantly effect the peak molar fraction of formation

of nitrogen dioxide (NO2) when natural gas was simulated with Mechanism-II and

Mechanism-III. There was no significantly effect was observed with Mechanism-I and

Mechanism-IV.

Ammonia (NH3) predicted profiles with simulation of natural gas combustion with four

mechanisms are shown in Figure 4.15 showing the similar discrepancies as that of NO and

NO2 profiles with each of kinetic mechanisms.

Table 4.8a Peak Concentrations (Mole Fraction) of NO2 at Various Equivalence ratios for Four Kinetic Mechanisms Equivalence Ratio Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

0.6 1.30E-07 1.40E-05 9.20E-06 2.25E-070.8 2.72E-06 4.00E-05 4.03E-05 3.40E-06

1 5.30E-07 2.07E-05 1.75E-05 6.73E-071.3 2.66E-08 9.12E-06 3.97E-06 6.92E-081.4 - 3.61E-06 4.10E-07 2.85E-06

86

Table 4.8b Peak Concentrations (Mole Fraction) of NO2 at Various Engine Speeds for Four Kinetic Mechanisms

Engine Speed Mechanism-I Mechanism-II Mechanism-III Mechanism-IV 2000 7.67E-08 1.38E-05 3.29E-06 2.28E-071500 7.73E-08 1.40E-05 1.31E-05 4.47E-073000 7.92E-07 1.33E-05 1.30E-05 2.25E-065000 8.28E-08 1.36E-05 1.28E-05 2.96E-077000 8.61E-08 1.36E-05 4.80E-06 2.25E-07

Table 4.8c Peak Concentrations (Mole Fraction) of NO2 at Various Initial Inlet

Temperatures for Four Kinetic Mechanisms Initial Temp (K) Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

1200 7.70E-08 1.40E-05 1.31E-05 2.25E-071500 6.54E-08 1.23E-05 9.20E-06 2.76E-072300 1.17E-07 9.38E-06 1.25E-05 2.62E-073100 1.81E-07 6.70E-06 1.29E-05 3.51E-074000 2.45E-07 4.17E-06 1.18E-05 4.51E-07

Table 4.8d Peak Concentrations (Mole Fraction) of NO2 at Various Compression

Ratios for Four Kinetic Mechanisms Compression Ratio Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

10.51 2.36E-07 1.13E-05 1.13E-05 2.62E-078 1.81E-07 1.03E-05 1.03E-05 1.98E-07

9.5 1.41E-04 1.09E-05 9.09E-07 2.36E-0711 2.47E-07 1.14E-05 1.14E-05 2.75E-07

The peak molar fraction of NH3 data showing effect of equivalence ratio, engine speed, and

initial inlet temperature on the NH3 formation with each kinetic mechanism is given in

Table 4.9a to Table 4.9c. The variation in peak molar fractions is shown by Box-and-

Whisker plots in Figure 4.16.

87

Figure 4.14 Variation in Peak Molar fractions of NO2 formation in IC engine for Four Kinetic Mechanisms at Various (A) Equivalence Ratios (B) Engine Speed, (C) Initial Inlet Temperature and (D) Compression Ratios

Following reactions involved in the formation and consumption of ammonia during the

simulation of natural gas combustion in IC engine (Table 4.10);

R-65 NH3(+M)<=>NH2+H(+M)

A

D C

B

Mechansims

Mol

e Fr

actio

n, N

O2

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0

5E-6

1E-5

1.5E-5

2E-5

2.5E-5

3E-5

3.5E-5

4E-5

4.5E-5

MaximumMinimum75%25%MedianOutliersExtremes

Mechansims

Mol

e Fr

actio

n, N

O2

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0

1.5E-6

3E-6

4.5E-6

6E-6

7.5E-6

9E-6

1.05E-5

1.2E-5

1.35E-5

1.5E-5

MaximumMinimum75%25%MedianOutliersExtremes

Mechansims

Mol

e Fr

actio

n, N

O2

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0

1.5E-6

3E-6

4.5E-6

6E-6

7.5E-6

9E-6

1.05E-5

1.2E-5

1.35E-5

1.5E-5

MaximumMinimum75%25%MedianOutliersExtremes

Mechasism

Mol

e Fr

actio

n, N

O2

Mechasism-I Mechasism-II Mechasism-III Mechasism-IV0

1.5E-5

3E-5

4.5E-5

6E-5

7.5E-5

9E-5

0.000105

0.00012

0.000135

0.00015

MaximumMinimum75%25%MedianOutliersExtremes

88

R-66 NH3+M<=>NH+H2+M

Figure 4.15 Ammonia (NH3) profiles at Equivalence Ratio ≈ 1.0, Engine Speed ≈ 3000 rpm, Tini =1500 K and Pini=0.67 atm

Both reactions are the third body ‘M’ reactions and rate of production analysis indicate that

R-66 contribute in the formation of ammonia while R-65 shows the consumption of

ammonia formed.

Table 4.9a Peak Concentrations (Mole Fraction) of NH3 at Various Equivalence ratios

for Four Kinetic Mechanisms Equivalence Ratio Mechanism-II Mechanism-III Mechanism-IV

0.6 1.38E-06 3.11E-07 2.29E-08 0.8 1.92E-07 1.83E-07 2.29E-08 1 8.61E-07 1.30E-07 7.02E-07

1.3 2.26E-06 7.02E-07 7.58E-06 1.4 3.34E-06 2.92E-06 1.94E-05

Crank rotation angle

Mol

e Fr

actio

n N

H3

Mol

e Fr

acrio

n N

H3,

(Mec

hans

im-II

I)

-150 -120 -90 -60 -30 0 30 60 90 120 1500 0

2E-7 2E-8

4E-7 4E-8

6E-7 6E-8

8E-7 8E-8

1E-6 1E-7

1.2E-6 1.2E-7

1.4E-6 1.4E-7

1.6E-6 1.6E-7Mechansim-IMechansim-IIMechanism-IIIMechanism-IV

89

Table 4.9b Peak Concentrations (Mole Fraction) of NH3 at Various Engine Speeds for Four Kinetic Mechanisms

Engine Speed (rpm) Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

2000 4.30E-06 1.62E-06 1.58E-06 3.05E-061500 2.41E-06 1.58E-06 1.66E-06 3.19E-063000 2.27E-06 1.66E-06 1.53E-06 2.98E-065000 2.23E-06 1.54E-06 1.65E-06 2.86E-067000 2.14E-06 1.66E-06 1.61E-06 2.86E-06

Table 4.9c Peak Concentrations (Mole Fraction) of NH3 at Various Initial Inlet

Temperatures for Four Kinetic Mechanisms Initial Temp (K) Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

1200 4.28E-06 1.60E-06 1.54E-06 2.85E-061500 3.82E-06 1.73E-06 3.11E-07 8.91E-072300 3.24E-06 2.13E-06 4.30E-07 4.35E-063100 1.85E-06 2.13E-06 1.57E-06 3.33E-064000 9.75E-07 1.70E-06 1.79E-06 1.96E-06

90

Figure 4.16 Variation in Peak Molar fractions of NH3 formation in IC engine for Four Kinetic Mechanisms at Various (A) Equivalence Ratios, (B) Engine Speed and (C) Initial Inlet Temperature.

Mechanisms

Mol

e Fr

actio

n,N

H3

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0

2E-6

4E-6

6E-6

8E-6

1E-5

1.2E-5

1.4E-5

1.6E-5

1.8E-5

2E-5

MaximumMinimum75%25%MedianOutliersExtremes

Mechanisms

Mol

e Fr

actio

ns, N

H3

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV1.5E-6

1.8E-6

2.1E-6

2.4E-6

2.7E-6

3E-6

3.3E-6

3.6E-6

3.9E-6

4.2E-6

4.5E-6

MaximumMinimum75%25%MedianOutliersExtremes

Mechansims

Mol

e Fr

actio

n, N

H3

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0

5E-7

1E-6

1.5E-6

2E-6

2.5E-6

3E-6

3.5E-6

4E-6

4.5E-6

MaximumMinimum75%25%MedianOutliersExtremes

A B

C

91

Table 4.10 Some Important Reactions and Parameters of rate coefficient k of Reversible Reaction for mechanism of Nitrogen compounds in proposed Reaction Mechanisms (A units mole-cm-sec-K, E units cal/mole)

SR. NO Reaction A b E 1 H2+CN=HCN+H 1.93E+04 2.9 6.8 2 CH4+N=NH+CH3 1.00E+13 0 100.4 3 CH4+CN=HCN+CH3 9.03E+04 2.6 -1.2 4 O2+N=NO+O 9.03E+09 1 27.2 5 O2+NH=HNO+O 3.91E+13 0 74.8 6 O2+NH=NO+OH 7.59E+10 0 6.4 7 O2+NH2=HNO+OH 1.51E+12 -0.4 151 8 O2+NH2=H2NO+O 1.10E+18 -1.3 140.6 9 O2+CN=NCO+O 7.23E+12 0 -1.7

10 O2+NCO=NO+CO2 1.72E+07 0 -3.1 11 CO+N2O=CO2+N2 9.77E+10 0 73 12 CO2+N=NO+CO 1.90E+11 0 14.2 13 N2+CH=HCN+N 1.57E+12 0 75.1 14 N2+CH2=HCN+NH 1.00E+13 0 309.6 15 NO+N2O=N2+NO2 1.00E+14 0 207.8 16 NO+N2H2=N2O+NH2 3.00E+12 0 0 17 NO+C=CN+O 1.93E+13 0 0 18 NO+C=CO+N 2.89E+13 0 0 19 NO+H=>N+OH 2.17E+14 0 207.1 20 N+OH=>NO+H 2.83E+13 0 0 21 NO+CH=CO+NH 1.20E+13 0 0 22 NO+CH=CN+OH 1.20E+13 0 0 23 NO+CH=HCN+O 9.60E+13 0 0 24 NO+CH2=HOCN+H 1.39E+12 0 -4.6 25 NO+CH2(S)=HCN+OH 9.64E+13 0 0 26 NO+CH3=HCN+H2O 9.28E+11 0 69.9 27 NO+CH3=H2CN+OH 9.28E+11 0 69.9 28 NO+HO2=NO2+OH 2.09E+12 0 -2 29 NO+HO2=HNO+O2 2.00E+11 0 8.3 30 NO+HCCO=HOCN+CO 2.00E+13 0 0 31 NO+N=>N2+O 4.28E+13 0 6.6 32 N2+O=>NO+N 1.81E+14 0 318.4 33 NO+NH=N2+OH 3.20E+13 0 53.2 34 NO+NH=N2O+H 4.16E+14 -0.5 0 35 NO+NH2=NNH+OH 2.41E+15 -1.2 0 36 NO+NH2=N2+H2O 5.48E+15 -1.2 0 37 NO+NNH=N2+HNO 5.00E+13 0 0 38 NO+HNO=N2O+OH 2.95E+05 0 0 39 NO+NCO=N2O+CO 1.39E+18 -1.7 3.240 NO+M=N+O+M 3.62E+15 0 620.6

92

Table 4.10 Some Important Reactions and Parameters of rate coefficient k of Reversible Reaction for mechanism of Nitrogen compounds in proposed Reaction Mechanisms (A units mole-cm-sec-K, E units cal/mole)- Continue

SR. NO Reaction A b E

41 NO2+NO2=NO+NO+O2 2.00E+12 0 112.2 42 NO2+H=NO+OH 3.47E+14 0 6.2 43 NO2+O=NO+O2 1.00E+13 0 2.5 44 NO2+N=NO+NO 8.07E+11 0 0 45 NO2+N=N2O+O 1.00E+12 0 0 46 NO2+NH=HNO+NO 1.00E+11 0.5 16.6 47 NO2+NH=N2O+OH 9.71E+12 0 0 48 NO2+NH2=N2O+H2O 2.03E+17 -1.7 0 49 NO2+CN=NCO+NO 3.00E+13 0 0 50 NO2+M=NO+O+M 3.13E+16 0 274.4 51 N2O+C=CN+NO 5.12E+12 0 0 52 N2O+H=N2+OH 4.37E+14 0 79 53 N2O+O=N2+O2 1.00E+14 0 117.2 54 N2O+O=NO+NO 6.92E+13 0 111.4 55 N2O+OH=N2+HO2 6.31E+11 0 41.6 56 N2O+N=N2+NO 1.00E+13 0 83.1 57 N2O+NH=HNO+N2 2.00E+12 0 24.9 58 N2O+CN=NCO+N2 1.00E+13 0 0 59 N2O+M=N2+O+M 2.86E+15 0 251 60 NH3+H=NH2+H2 5.42E+05 2.4 41.5 61 NH3+O=>NH2+OH 9.64E+12 0 30.5 62 NH3+OH=NH2+H2O 3.16E+12 0 8.4 63 NH3+HO2=NH2+H2O2 2.51E+12 0 99.8 64 NH3+NH2=N2H3+H2 7.94E+11 0.5 90.2 65 NH3(+M)=NH2+H(+M) 8.30E+15 0 458.7 66 NH3+M=NH+H2+M 1.80E+15 0 390.8 67 N2H2+H=NNH+H2 1.00E+13 0 4.2 68 N2H2+O=NH2+NO 1.00E+13 0 0 69 N2H2+O=NNH+OH 1.00E+11 0.5 0 70 N2H2+OH=NNH+H2O 1.00E+13 0 8.3 71 N2H2+NH=NNH+NH2 1.00E+13 0 4.2 72 N2H2+NH2=NH+N2H3 1.00E+11 0.5 141.3 73 N2H2+NH2=NH3+NNH 1.00E+13 0 16.6 74 N2H2+M=NNH+H+M 2.50E+16 0 207.8 75 N2H2+M=NH+NH+M 7.91E+16 0 415.7 76 C2N2+O=NCO+CN 1.29E+14 0 59.3 77 C2N2+OH=HOCN+CN 1.87E+11 0 12 78 HCN+O=NCO+H 8.45E+05 2.1 25.6

93

Table 4.10. Some Important Reactions and Parameters of rate coefficient k of Reversible Reaction for mechanism of Nitrogen compounds in proposed Reaction Mechanisms (A units mole-cm-sec-K, E units cal/mole)- Continue

SR. NO Reaction A B E 79 HCN+O=NH+CO 3.19E+05 2.1 25.6 80 HCN+O=CN+OH 2.22E+05 2.1 25.6 81 HCN+OH=CN+H2O 9.03E+12 0 44.9 82 HCN+OH=HOCN+H 5.85E+04 2.4 52.3 83 HCN+OH=HNCO+H 1.98E-03 4 4.2 84 HCN+CN=C2N2+H 3.80E+07 1.6 0.4 85 HOCN+H=H2O+CN 1.00E+12 0 0 86 HOCN+H=H2+NCO 1.00E+12 0 0 87 HOCN+H=HNCO+H 1.00E+13 0 0 88 HNCO+H=NCO+H2 2.05E+14 -0.3 84.7 89 HNCO+H=NH2+CO 1.10E+14 0 53.2 90 HNCO+O=NH+CO2 2.00E+13 0 54.5 91 HNCO+O=HNO+CO 1.90E+12 0 43.1 92 HNCO+O=OH+NCO 2.00E+14 0 96.4 93 HNCO+OH=NCO+H2O 1.99E+12 0 23.2 94 HNCO+OH=NH2+CO2 6.62E+11 0 23.2 95 HNCO+HO2=NCO+H2O2 3.00E+13 0 121.3 96 HNCO+N=NH+NCO 3.98E+13 0 149.7 97 HNCO+NH=NH2+NCO 3.00E+13 0 99.2 98 HNCO+NH2=NH3+NCO 1.00E+12 0 29.1 99 HNCO+M=NH+CO+M 2.40E+16 0 354.5

100 HNCO+M=H+NCO+M 2.86E+17 0 468.9 101 H+NH=N+H2 1.02E+13 0 0 102 H+NH2=NH+H2 6.02E+12 0 0 103 H+NNH=N2+H2 3.98E+13 0 12.5 104 H+N2H3=NH2+NH2 1.58E+12 0 0 105 H+N2H3=NH+NH3 1.00E+11 0 0 106 H+N2H3=N2H2+H2 1.00E+12 0 8.3 107 H+HNO=H2+NO 1.26E+13 0 16.6 108 H+NCO=NH+CO 5.24E+13 0 0 109 CH+N=CN+H 1.26E+13 0 0 110 CH+NH=HCN+H 5.00E+13 0 0 111 CH+NH2=HCN+H+H 3.00E+13 0 0 112 CH2+N=HCN+H 5.00E+13 0 0 113 CH2+NH=HCN+H+H 3.00E+13 0 0 114 CH3+N=H2CN+H 2.59E+14 0 3.5 115 C2H3+N=HCN+CH2 2.00E+13 0 0 116 H2CCCH+N=HCN+C2H2 1.00E+13 0 0

94

Table 4.10 Some Important Reactions and Parameters of rate coefficient k of Reversible Reaction for mechanism of Nitrogen compounds in proposed Reaction Mechanisms (A units mole-cm-sec-K, E units cal/mole)-Continue

SR. NO Reaction A b E

117 O+NH=N+OH 3.72E+13 0 0 118 O+NH=NO+H 5.50E+13 0 0 119 O+NH2=NH+OH 6.90E+11 0.3 -0.8 120 O+NH2=HNO+H 8.93E+14 -0.5 1.4 121 O+NNH=N2+OH 1.00E+13 0 20.8 122 O+NNH=N2O+H 1.00E+13 0 12.5 123 O+NNH=NH+NO 1.65E+14 -0.2 -4.2 124 O+HNO=OH+NO 5.01E+11 0.5 8.3 125 O+CN=CO+N 1.02E+13 0 0 126 O+NCO=NO+CO 3.16E+13 0 0 127 OH+NH=HNO+H 1.00E+12 0.5 8.3 128 OH+NH=N+H2O 5.01E+11 0.5 8.3 129 OH+NH2=>O+NH3 1.99E+10 0.4 2.1 130 OH+NH2=NH+H2O 5.01E+11 0.5 8.3 131 OH+NNH=N2+H2O 3.16E+13 0 0 132 OH+HNO=NO+H2O 1.08E+13 0 0 133 OH+CN=NCO+H 6.02E+13 0 0 134 OH+NCO=NO+HCO 5.00E+12 0 62.8 135 OH+NCO=NO+CO+H 1.00E+13 0 0 136 HO2+NH2=HNO+H2O 1.57E+13 0 0 137 HCCO+N=HCN+CO 5.00E+13 0 0 138 N+N+M=N2+M 6.52E+15 0 0 139 N+NH=N2+H 6.31E+11 0.5 0 140 N+NH2=N2+H+H 6.93E+13 0 0 141 N+NNH=NH+N2 3.16E+13 0 8.3 142 N+CN=>C+N2 1.81E+14 0 0 143 C+N2=>N+CN 5.24E+13 0 187.9 144 N+H2CN=N2+CH2 2.00E+13 0 0 145 N+NCO=NO+CN 2.77E+18 -1 72.2 146 N+NCO=N2+CO 1.99E+13 0 0 147 NH+NH=N2+H+H 5.13E+13 0 0 148 NH+NH2=N2H2+H 1.51E+15 -0.5 0 149 NH+NNH=N2+NH2 2.00E+11 0.5 8.3 150 NH+M=N+H+M 7.57E+14 0 315.9 151 NH2+NH2=N2H2+H2 3.98E+13 0 49.9 152 NH2+NH2=NH3+NH 5.00E+13 0 41.8 153 NH2+M=NH+H+M 7.91E+23 -2 382.4

95

Table 4.10 Some Important Reactions and Parameters of rate coefficient k of Reversible Reaction for mechanism of Nitrogen compounds in proposed Reaction Mechanisms (A units mole-cm-sec-K, E units cal/mole)-Continue

SR. NO Reaction A b E 151 NH2+NH2=N2H2+H2 3.98E+13 0 49.9 152 NH2+NH2=NH3+NH 5.00E+13 0 41.8 153 NH2+M=NH+H+M 7.91E+23 -2 382.4 154 NH2+NNH=N2+NH3 1.00E+13 0 0 155 NH2+HNO=NH3+NO 5.01E+11 0.5 4.2 156 NNH=N2+H 3.00E+08 0 0 157 NNH+M=N2+H+M 2.50E+13 0.5 12.8 158 NNH+O2=N2+HO2 5.00E+12 0 0 159 N2H3+M=N2H2+H+M 2.50E+16 0 207.8 160 N2H3+M=NH2+NH+M 2.50E+16 0 174.6 161 HNO+M=H+NO+M 5.09E+16 0 203.7 162 H2CN+M=HCN+H+M 7.50E+14 0 92 163 NCO+M=N+CO+M 2.91E+15 0 195.4 164 HO+CH=CHO+H 5.72E+12 0 -3.2 165 N2O+O=NO2+N2 1.0E+17 0 0.0

4.7.2 Formation of Carbon Monoxide (CO):

Carbon monoxide is found in the combustion products of all carbonaceous fuels. In

equilibrium the carbon monoxide is given by: CO2 → CO + 0.5O2, and in this case the CO

concentration is dependent on the temperature and excess air. In fuel-rich regions of a

flame, the CO levels are necessarily high since there is insufficient oxygen for complete

combustion. Only if sufficient air is mixed with such gases at sufficiently high temperature

the CO can be oxidized. Thus, imperfect mixing can allow carbon monoxide to escape

from combustion chamber that is operated at fuel-lean mixtures. In premixed combustion

systems, the carbon monoxide levels can be relatively high due to the high equilibrium

concentrations at the flame temperature, particularly in internal combustion engines where

the gases are hot prior to ignition due to compression. As the combustion products are

cooled, the equilibrium CO levels decreases. In flames, the concentration of CO is formed

rapid in the reaction zone and is subsequently oxidized to CO2 by: CO + OH → CO2 + H.

96

If the time available for reaction of CO to CO2 is short, particularly in small combustion

chambers, the CO in the burned gases is higher than that for large units.

The proposed kinetic mechanisms were simulated to predict the combustion

chamber pressure, temperature, major combustion products (CO2 & H2O) and formation of

nitrogen containing pollutants like NOx (as sum of NO & NO2), NH3 and carbon monoxide

(CO). In this section, the prediction of formation of CO in IC engine is discussed. The input

simulation parameters are given in Table 4.1 and Table 4.2a to Table 4.2c.

Figure 4.17 shows the predicted profiles of formation of carbon monoxide (CO) in IC

engine when natural gas was used as fuel.

The CO prediction profiles illustrate that high temperature (Mechanism-II) and low

temperature (Mechanism-III) shows the early CO formation which indicate that these

mechanisms contains the reactions which have low activation energy and results do not

agree with the experimental measurements ( discussed in Chapter-5). Mechanism-I and

Mechanism-IV indicate the start of combustion at -7.6° and -13.2° respectively which

occur during the combustion phase of engine cycle and agree with the experimentally

measured results of start of ignition flame in IC engine combustion chamber. The peak CO

molar fractions achieved near -2.68° of crank rotation angle at the end combustion

reactions with Mechanism-I and Mechanism-IV. The CO profiles (Mechanism-I &

Mechanism-IV) indicate that both mechanisms contain such types of reactions which

govern the reactions in the formation of CO in combustion chamber of IC engine

practically given Table 4.12. Further investigation of each mechanism, rate of production

analysis (done by the Chemkin 4.1.1) shows that R-783, R-934 of Mechanism-I contribute

in the formation of carbon monoxide (CO) and R-141, R-205 are significant producer of

CO during the combustion chamber of IC engine.

97

The peak molar fraction data are given in Table 4.11a to 4.11d obtained during the

investigation of effect of equivalence ratio, engine speed, and initial inlet temperature and

compression ratio. The peak molar fraction of CO was observed at equivalence ratio of

≈1.4, engine speed of ≈3000 rpm and initial inlet temperature of 1200 K for Mechanism-IV

as give in Table 4.11.

Figure 4.17 Carbon monoxide (CO) profiles at Equivalence Ratio ≈ 1.0, Engine Speed ≈ 3000 rpm, Tini =1500 K and Pini=0.67 atm

Table 4.11a Peak Concentrations (Mole Fraction) of CO at Various Equivalence

ratios for Four Kinetic Mechanisms Equivalence Ratio Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

0.6 0.0900 0.0367 0.0034 0.0824 0.8 0.0527 0.0172 0.0004 0.0518 1 0.0786 0.0310 0.0025 0.0723

1.3 0.1015 0.0410 0.0034 0.0927 1.4 0.1134 0.0438 0.0065 0.1096

Crank rotation angle

Mol

e Fr

actio

n, C

O

-150 -120 -90 -60 -30 0 30 60 90 120 150 1800

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

0.055

0.06

0.065

0.07

0.075

0.08

Mechansim-IMechansim-IIMechanism-IIIMechanism-IV

98

Table 4.11b Peak Concentrations (Mole Fraction) of CO at Various Initial Inlet Temperatures for Four Kinetic Mechanisms

Initial Temp (K) Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

1200 0.0870 0.0372 0.0163 0.0824 1500 0.0882 0.0401 0.0034 0.0811 2300 0.0872 0.0416 0.0121 0.0823 3100 0.0846 0.0418 0.0193 0.0805 4000 0.0820 0.0410 0.0206 0.0778

Table 4.11c Peak Concentrations (Mole Fraction) of CO at Various Engine Speeds for

Four Kinetic Mechanisms Engine Speed (rpm) Mechanism-I Mechanism-II Mechanism-III Mechanism-IV

2000 0.0869 0.0374 0.0006 0.0822 1500 0.0869 0.0403 0.0151 0.0819 3000 0.0870 0.0301 0.0212 0.0824 5000 0.0880 0.0329 0.0169 0.0844 7000 0.0871 0.0340 0.0014 0.0824

Table 4.11d Peak Concentrations (Mole Fraction) of CO at Various Compression

Ratios for Four Kinetic Mechanisms Compression

Ratio Mechanism-I Mechanism-IIMechanism-III Mechanism-IV

10.51 0.08516656 0.0473 0.0473 0.08496 8 0.08516455 0.0455 0.0455 0.08495

9.5 0.08516585 0.0468 0.0468 0.08494 11 0.08516685 0.0474 0.0474 0.08499

Figure 4.18 shows variation of peak CO molar fraction caused by the variation in

equivalence ratio, engine speed, initial inlet temperature and compression ratio. The results

show that carbon monoxide (CO) peak molar fractions are significantly dependent of the

fuel-to-air equivalence ratio than other input variables.

99

Figure 4.18 Variation in Peak Molar fractions of NO formation in IC engine for Four Kinetic Mechanisms at Various (A) Equivalence Ratios (B) Engine Speed and (C) Initial Inlet Temperature.

Mechansims

Mol

e Fr

actio

n, C

O

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0

0.015

0.03

0.045

0.06

0.075

0.09

0.105

0.12

MaximumMinimum75%25%MedianOutliersExtremes

Mechansims

Mol

e Fr

actio

n, C

O

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

MaximumMinimum75%25%MedianOutliersExtremes

Mechansims

Mol

e Fr

actio

n, C

O

Mechansim-I Mechansim-II Mechansim-III Mechansim-IV0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

MaximumMinimum75%25%MedianOutliersExtremes

Mechanism

Mol

e Fr

actio

n, C

O

Mechasism-I Mechasism-II Mechasism-III Mechasism-IV0.044

0.048

0.052

0.056

0.06

0.064

0.068

0.072

0.076

0.08

0.084

0.088

MaximumMinimum75%25%MedianOutliersExtremes

A B

C D

100

able 4.12 Reactions in Four Kinetic Mechanisms (Proposed) in CO Formation and Consumption

Mechanism Reactions

Mechanism-I

R-782. CO+N2O<=>CO2+N2

R-783. CO2+N<=>NO+CO

R-870. HNCO+M<=>NH+CO+M

R-934. NCO+M<=>N+CO+M

Mechanism-II

R-640. CO+N2O<=>CO2+N2

R-641. CO2+N<=>NO+CO

R-708. HCN+O<=>NH+CO

R-718. NCO+H<=>NH2+CO

R-728. HNCO+M<=>NH+CO+M

R-737. H+NCO<=>NH+CO

R-753. O+CN<=>CO+N

R-754. O+NCO<=>NO+CO

R-763. OH+NCO<=>NO+CO+H

R-791. NCO+M<=>N+CO+M

Mechanism-III

R-711. CO+N2O<=>CO2+N2

R-712. CO2+N<=>NO+CO

R-779. HCN+O<=>NH+CO

R-789. HNCO+H<=>NH2+CO

R-808. H+NCO<=>NH+CO

R-826. O+NCO<=>NO+CO

R-835. OH+NCO<=>NO+CO+H

R-863. NCO+M<=>N+CO+M

Mechanism-IV

R-141. HNCO+M<=>NH+CO+M

R-177. OH+NCO<=>NO+CO+H

R-205. NCO+M<=>N+CO+M

101

4.8 Parametric Uncertainty Analysis of Kinetic Mechanisms: The simulation input parameters have not the accurate values and therefore the exact

prediction of emission and other combustion profiles is not possible and errors always exist

in the results. In the combustion studies, the main sources of errors are kinetic and

thermodynamic parameters because their values are calculated by the estimation methods

and approximations.

In IC engines, the predicted profiles is not the accurate ones and have always uncertainties.

In addition to kinetic and thermodynamic related uncertainties (detail is discussed in

Chapter-8), in an IC engine, these errors may also been contributed by some operating

parameters such as equivalence ratio, engine speed, initial temperature of gas mixture

charged into combustion chamber. Mathematically, the contribution of individual

parameter is defined by;

( )( ) 100% 2

2

×=i

ij

Y

YijS

σ

σ (12)

Where ( )ij Y2

σ and ( )iY2

σ are given by;

( )iPiTiSieqi YYYYY 22222 )()()()( σσσσσ +++= (13)

and

( )ij

jij YY ∑= 22 )( σσ

σeq, σs, σT, and σp are the variance coefficients due to fuel to air equivalence ratio, engine

operating speed, initial inlet temperature and initial inlet pressure respectively.

Equation 4.13 shows the sum of variance of shows the percentage air equivalence ratio,

engine operating speed, initial inlet temperature and initial inlet pressure origin,

respectively used to calculate the percentage contribution each individual parameters. The

102

Chemkin 4.1.1 has built in routine to calculate the S%ij due to above mentioned operating

parameters of IC engine when combustion of natural gas is simulated by the four kinetic

models (mechanisms). The estimated model of formation each pollutants due to input of

these operating parameters were developed.

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

15.7%

81.4%

0.0%2.9%

(a)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

0.0% 0.0%3.8%

(b)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

0.6% 0.0% 0.1%

(c)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

0.2% 0.0% 0.0%

(d)

103

Figure 4.19 Percentage Contribution of Four Input Operating Variables of the Uncertain output of Concentrations of H2O(a), CO2(b), CO (c), NO (d), NO2 and NH3 in IC engine when combustion simulated for Mechanism-I

Estimated models were carried out and calculated the percentage contribution of each

selected operating parameters. Figure 19 to Figure 22 shows the percentage contribution of

uncertainty of above operating parameters for four kinetic mechanisms. Each figure

indicate that all the parameters contribution to the uncertainty to out of approximate models

but fuel to air equivalence ratio is major source of uncertainty in the predicted

concentrations of pollutants in IC engine with proposed kinetic models. For mechanism-IV,

engine speed is the second major contributor to the uncertain out put of concentrations of

each pollutant.

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

1.8%0.0% 0.0%

(e)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

3.6%0.0% 0.0%

(f)

104

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

1.0%

88.1%

10.8%

0.1%

(a)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

4.6%

89.1%

6.1%

0.3%

(b)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

0.8%

91.7%

7.4%

0.0%

(c)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

1.8%

94.2%

3.7%0.3%

(d)

105

Figure 4.20 Percentage Contribution of Four Input Operating Variables of the Uncertain output of Concentrations of H2O(a), CO2(b), CO (c), NO (d), NO2 and NH3 in IC engine when combustion simulated for Mechanism-II

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

3.3%

87.6%

2.8%6.2%

(f)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

Speed Equivalance Ratio Pressure Temperature

0.0%

74.6%

22.8%

2.5%

(e)

106

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

1.0%

88.1%

10.8%

0.1%

(a)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

4.6%

89.1%

6.1%

0.3%

(b)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

0.8%

91.7%

7.4%

0.0%

(c)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

1.8%

94.2%

3.7%0.3%

(d)

107

Figure 4.21 Percentage Contribution of Four Input Operating Variables of the Uncertain output of Concentrations of H2O(a), CO2(b), CO (c), NO (d), NO2 and NH3 in IC engine when combustion simulated for Mechanism-III

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

3.3%

87.6%

2.8%6.2%

(f)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

Speed Equivalance Ratio Pressure Temperature

0.0%

74.6%

22.8%

2.5%

(e)

108

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

88.7%

10.4%

0.0% 0.9%

(a)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

Speed Equivalance Ratio Pressure Temperature

17.3%

68.7%

0.5%

13.5%

(b)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

Speed Equivalance Ratio Pressure Temperature

27.9%

72.0%

0.0% 0.2%

(c)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

Speed Equivalance Ratio Pressure Temperature

21.9%

0.0% 0.0%

(d)

109

Figure 4.22 Percentage Contribution of Four Input Operating Variables of the Uncertain output of Concentrations of H2O(a), CO2(b), CO (c), NO (d), NO2 and NH3 in IC engine when combustion simulated for Mechanism-IV

4.12 Summary:

In this chapter, combustion of natural gas in IC engine was simulated using four

different kinetic reaction mechanisms (models) to predict the formation of pollutants.

Parametric analysis of these kinetic mechanisms was carried using Chemkin 4.1.1

simulation software. In this analysis the affect of important IC engine operating variables

such as fuel to air equivalence ratio, engine speed, initial inlet temperature of feed mixture

etc were analyzed in the formation pollutants including CO, NO, NO2 and NH3. The

formation profiles of cylinder temperature, pressure, major combustion species (CO2, H2O)

and major gaseous pollutants were obtained at the stoichiometric combustion. The

simulation data showing the effect of these operating parameters is also discussed for each

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

83.9%

16.0%

0.0% 0.0%

(e)

Uncertain Parameter

Perc

enta

ge C

ontr

ibut

ion

0

20

40

60

80

100

Speed Equivalance Ratio Pressure Temperature

80.7%

19.3%

0.0% 0.0%

(f)

110

mechanism. The discrepancies in the predicted profiles of each mechanism for each specie

is also discussed.

The uncertainty analysis of each kinetic mechanism predicts that equivalence ratio

is major source of uncertainty in the predicted concentrations of pollutants in IC engine

with proposed kinetic models. For mechanism-IV, engine speed is the second major

contributor to the uncertainty output of concentrations of each pollutant.

Based upon the simulation results and discrepancies, it is recommend that

Mechanism-I and Mechanism-IV are appropriate mechanisms to represent the combustion

of natural gas in IC engines but due to computational limitations, Mechanism-IV is best

choice among the proposed reaction scheme to predict the combustion temperature,

pressure and pollutants profiles in combustion chamber of IC engine.

The common types of reactions involved in the formation of pollutants is given in

Table 41.3

Table 4.13 Reactions Involved in Formation and Consumption of Pollutants in IC Engine

Pollutants Reaction A (mol-cm-sec-k) b E (cal/mol)

Ammonia (NH3)

NH3+H=NH2+H2 5.42E+05 2.4 41.5 NH3+O=>NH2+OH 9.64E+12 0 30.5 NH3+OH=NH2+H2O 3.16E+12 0 8.4 NH3+HO2=NH2+H2O2 2.51E+12 0 99.8 NH3+NH2=N2H3+H2 7.94E+11 0.5 90.2 NH3=NH2+H 8.30E+15 0 458.7 NH3+M=NH+H2+M 1.80E+15 0 390.8 NH3+HO2=NH2+H2O2 2.51E+12 0 99.8 NH3+NH2=N2H3+H2 7.94E+11 0.5 90.2 NH3=NH2+H 8.30E+15 0 458.7 NH3+M=NH+H2+M 1.80E+15 0 390.8 HNCO+NH2=NH3+NCO 1.00E+12 0 29.1 H+N2H3=NH+NH3 1.00E+11 0 0 OH+NH2=>O+NH3 1.99E+10 0.4 2.1 NH2+NH2=NH3+NH 5.00E+13 0 41.8 NH2+NNH=N2+NH3 1.00E+13 0 0 NH2+HNO=NH3+NO 5.01E+11 0.5 4.2

Nitric Oxide (NO)

O2+N=NO+O 9.03E+09 1 27.2 O2+NH=NO+OH 7.59E+10 0 6.4 O2+NCO=NO+CO2 1.72E+07 0 -3.1

111

CO2+N=NO+CO 1.90E+11 0 14.2 NO+N2O=N2+NO2 1.00E+14 0 207.8 NO+N2H2=N2O+NH2 3.00E+12 0 0 NO+C=CN+O 1.93E+13 0 0 NO+C=CO+N 2.89E+13 0 0 NO+H=>N+OH 2.17E+14 0 207.1 N+OH=>NO+H 2.83E+13 0 0 NO+CH=CO+NH 1.20E+13 0 0 NO+CH=CN+OH 1.20E+13 0 0 NO+CH=HCN+O 9.60E+13 0 0 NO+CH2=HOCN+H 1.39E+12 0 -4.6 NO+CH2(S)=HCN+OH 9.64E+13 0 0 NO+CH3=HCN+H2O 9.28E+11 0 69.9 NO+CH3=H2CN+OH 9.28E+11 0 69.9 NO+HO2=NO2+OH 2.09E+12 0 -2 NO+HO2=HNO+O2 2.00E+11 0 8.3 NO+HCCO=HOCN+CO 2.00E+13 0 0 NO+N=>N2+O 4.28E+13 0 6.6 N2+O=>NO+N 1.81E+14 0 318.4 NO+NH=N2+OH 3.20E+13 0 53.2 NO+NH=N2O+H 4.16E+14 -0.5 0 NO+NH2=NNH+OH 2.41E+15 -1.2 0 NO+NH2=N2+H2O 5.48E+15 -1.2 0 NO+NNH=N2+HNO 5.00E+13 0 0 NO+HNO=N2O+OH 2.95E+05 0 0 NO+NCO=N2O+CO 1.39E+18 -1.7 3.2 NO+M=N+O+M 3.62E+15 0 620.6 NO2+NO2=NO+NO+O2 2.00E+12 0 112.2 NO2+H=NO+OH 3.47E+14 0 6.2 NO2+O=NO+O2 1.00E+13 0 2.5 NO2+N=NO+NO 8.07E+11 0 0 NO2+NH=HNO+NO 1.00E+11 0.5 16.6 NO2+CN=NCO+NO 3.00E+13 0 0 NO2+M=NO+O+M 3.13E+16 0 274.4 N2O+C=CN+NO 5.12E+12 0 0 N2O+O=NO+NO 6.92E+13 0 111.4 N2O+N=N2+NO 1.00E+13 0 83.1 N2H2+O=NH2+NO 1.00E+13 0 0 H+HNO=H2+NO 1.26E+13 0 16.6 O+NH=NO+H 5.50E+13 0 0 O+NNH=NH+NO 1.65E+14 -0.2 -4.2 O+HNO=OH+NO 5.01E+11 0.5 8.3 O+NCO=NO+CO 3.16E+13 0 0 OH+HNO=NO+H2O 1.08E+13 0 0 OH+NCO=NO+HCO 5.00E+12 0 62.8 OH+NCO=NO+CO+H 1.00E+13 0 0 N+NCO=NO+CN 2.77E+18 -1 72.2 NH2+HNO=NH3+NO 5.01E+11 0.5 4.2 HNO+M=H+NO+M 5.09E+16 0 203.7

Carbon CO+N2O=CO2+N2 9.77E+10 0 73

112

monoxide (CO)

CO2+N=NO+CO 1.90E+11 0 14.2 NO+C=CO+N 2.89E+13 0 0 NO+CH=CO+NH 1.20E+13 0 0 NO+HCCO=HOCN+CO 2.00E+13 0 0 NO+NCO=N2O+CO 1.39E+18 -1.7 3.2 HCN+O=NH+CO 3.19E+05 2.1 25.6 HNCO+H=NH2+CO 1.10E+14 0 53.2 HNCO+O=HNO+CO 1.90E+12 0 43.1 HNCO+M=NH+CO+M 2.40E+16 0 354.5 H+NCO=NH+CO 5.24E+13 0 0 O+CN=CO+N 1.02E+13 0 0 O+NCO=NO+CO 3.16E+13 0 0 OH+NCO=NO+CO+H 1.00E+13 0 0 HCCO+N=HCN+CO 5.00E+13 0 0 N+NCO=N2+CO 1.99E+13 0 0 NCO+M=N+CO+M 2.91E+15 0 195.4 NCO+M=N+CO+M 2.91E+15 0 195.4

Nitrogen dioxide (NO2)

NO+N2O=N2+NO2 1.00E+14 0 207.8 NO+N2H2=N2O+NH2 3.00E+12 0 0 NO2+NO2=NO+NO+O2 2.00E+12 0 112.2 NO2+H=NO+OH 3.47E+14 0 6.2 NO2+O=NO+O2 1.00E+13 0 2.5 NO2+N=NO+NO 8.07E+11 0 0 NO2+N=N2O+O 1.00E+12 0 0 NO2+NH=HNO+NO 1.00E+11 0.5 16.6 NO2+NH=N2O+OH 9.71E+12 0 0 NO2+NH2=N2O+H2O 2.03E+17 -1.7 0 NO2+CN=NCO+NO 3.00E+13 0 0 NO2+M=NO+O+M 3.13E+16 0 274.4

Carbon Dioxide (CO2)

O2+NCO=NO+CO2 1.72E+07 0 -3.1 CO+N2O=CO2+N2 9.77E+10 0 73 CO2+N=NO+CO 1.90E+11 0 14.2 HNCO+O=NH+CO2 2.00E+13 0 54.5 HNCO+OH=NH2+CO2 6.62E+11 0 23.2

113

CHAPTER-5

Sensitivity and Rate of Production Analysis

of Detailed Kinetic Mechanisms

In this chapter, the Rate of Production (ROP) and

Sensitivity Analysis (SA) is applied to the proposed reaction

mechanisms. ROP analysis identified the reactions involved

in the formation of pollutant species (CO, NO, NO2, & NH3).

The absolute & normalized rate of production coefficients

was determined for each of reactions in each mechanism.

The sensitivity analysis was carried to determine the

effect of rates of each reaction of the mechanism on the

predicted concentrations of pollutant species. In this

analysis, normalized logarithmic sensitivity coefficient was

determined for each reaction contributing the output

concentrations of the selected pollutant species. These two

analysis were carried out for two extreme temperatures i.e.

1500 K and 4000 K under stoichiometric conditions (when

φ=1.0).

114

5.1 Introduction:

Sensitivity analysis, principal component analysis of the sensitivity matrix, and

rate-of-production analysis are useful tools in interpreting detailed chemical kinetics

calculations. Detailed chemical reaction mechanisms are often used in the analysis of

gaseous chemical reactions such as combustion processes, processes in the upper

atmosphere and chemical vapour deposition processes. During the development and use of

a detailed chemical kinetic model, it is important to understand the role of specific

reactions.

5.2 Rate of Production Analysis:

Rate-of-production analysis is important tool to understand the reaction system in IC

engine. Rate-of-production analysis helps to determine the contribution of each elementary

reaction in the kinetic mechanism to the net production or destruction rates of a species.

Rate-of-production analysis is particularly useful for IC engine combustion (a type of 0-D

reactor system) where it is possible to consider data from a large reaction and therefore the

computational expense is small.

Most of the chemical reactions in combustion are the binary reactions where two reacting

molecules, say A& B, with the capability of reacting together collide and form two product

molecules, C & D given as;

A+B ↔ C+D

According to law of mass action, the rate at which product species produced and rate at

which reactant species are removed is proportional to the product of the concentration of

reacting species, with the concentration of each species raised to the power of its

stoichiometric coefficient,

115

Thus for above reaction, the reaction rate R+ in forward (+) direction, reactants to product is

given as;

[ ] [ ] [ ][ ]BAkR dtCd

dtAd ++ ==−=

++

(1)

If the reaction can proceed in the reverse (-) direction, then the backward reaction rate R- is

given by;

[ ] [ ] [ ][ ]DCkR dtAd

dtCd −==−=

−−_ (2)

Where k+ and k- are the rate constants in the forward and reverse directions for the above

general type of reaction.

The net rate of production of products or removal of reactants is;

[ ] [ ] [ ] [ ]dtAd

dtAd

dtCd

dtCdRR

−+−+

−−=+=− −+

[ ][ ] [ ][ ]DCkBAk −+ −= (3)

More generally,

[ ]Cn

i

RiRXkR

1=

++ = ν (4)

[ ]Cn

i

piPiXkR

1=

−− = ν (5)

The net rate of removal of reactant species XRi is;

[ ] ( )−+ −=− RRRidtXd Ri ν (6)

And the net rate of production of the product species Xpi is;

[ ] ( )−+ −=− RRPidtXd pi ν (7)

The molar production of a species per unit volume of IC engine combustion chamber,

Pk, is given by;

i

I

ikik qP ∑

=

•

+=1υω (8)

116

Where

υki Stoichiometric coefficients for the gas reactions,

qi Rate of progress of the gas-phase reactions.

The contribution to the rate of production of species from gas-phase reaction is;

ikiki qC υ= (9)

The reactor model computes normalized values of the reaction contributions to the species

production and destruction rates. The normalized production-contributions for gas-phase

reactions are given by:

(10)

And the normalized destruction values for the gas-phase reactions are given by:

(11)

Thus, the normalized contributions to production and destruction sum to one, as follows:

(12) In transient simulations, when rate-of-production analysis is requested, the above

calculations are performed at every time step.

5.3 Sensitivity Analysis of Detailed Kinetic Mechanisms:

One method for this is sensitivity analysis, a field which has been studied

extensively. Several publications on sensitivity analysis are available, including the reviews

by Rabitz et al. (1983), Tura´nyi (1990a), Radhakrishnan (1991) and Tomlin et al. (1997);

however, apart from an article by Yetter et al. (1985), most reported work focus on the

mathematical foundations of sensitivity analysis.

117

In analysis of a detailed kinetic model (mechanism), it is interesting to identify

which reaction is more vulnerable to concentration of pollutants formed during the

combustion in IC engine. According to the reaction rate law, the rate of reaction is directly

linked with the reaction rate constant, “k” (as defined by Arrhenius Law) and this rate

constant is dependent on the temperature. Thus the variation in “k” affects the rate constant

for a reaction step. In current study, this variation in reaction rate is used to identify how

the formation of a specie (or pollutants) is varied , the normalized sensitivity coefficients

(by perturbation of Arrhenius Coefficient “A”) were calculated for each reaction in the

detailed kinetic mechanisms to identify which reaction effect the concentration of each

pollutants studied.

5.3.1 Local Sensitivity Analysis of Pollutants Formation in IC Engine:

The change in concentration of species (like CO2, CO, NO, NO2, NH3) formed in

flame during the combustion of pre-mixed fuel in IC engine is correlated to reaction rate

and other reactor parameters is defined by the equation (13).

( ) ( )ii

m

ijijdx

dcdt

dc kRkcfjj ∑=

===1

, νυ (13)

Where; { }∏=

⟩=n

jji

njii ockR

1

νν

This differential equation defines the link of detailed chemical kinetic model of the

processes occurring in a 0-D homogeneous plug-flow reactor. In above equation, “c” is

specie concentration and k denotes the reaction rate constants defined by Arhenous Law;

TRiE

eTAk iii

.,0−= β

(14)

The solution (i.e. the dependent parameters) of this model is a vector of outlet

concentrations. The independent parameters are the problem conditions, i.e. the inlet

118

concentrations, pressure, temperature and residence time as well as the parameters

describing the rates of the reactions, as defined by the Arrhenius expression Equation (14).

Dependent on the physical system studied, Equation (13) may be expanded, but the general

concepts will remain the same. For simplicity, the present discussion will be based on

Equation (13). In the formulation of a kinetic model, it is useful to know the impact of

modifications of parameters. This knowledge is often obtained through sensitivity analysis,

i.e., by perturbation of the parameter vector by Δk and by observing the change in the

vector of predicted concentrations. A low order Taylor expansion Equation. (15) of the

perturbation of the parameter vector is often used.

( ) ∑∑∑===

∂∂ −−−−−+ΔΔ+Δ+=Δ+

m

jjikk

cm

ij

m

jkc

ii kkkktckktcji

i

j

i

1121

1

2

,),( δδδ

(15)

Usually, only the first term of the Taylor expansion is included. This first term is often

called the (local first order) sensitivity coefficient. The integrated local first order

sensitivity coefficients may be obtained from the differential Equation (16) and solved

efficiently together with Equation (13) (Dunker, 1981).

( ) ( )jjj ktf

kc

kc

dtd tj δ

δδδ

δδ += (16)

The sensitivity coefficients obtained by solution of Equation (16) are not suited for analysis

since Equation (16) provides an un-scaled value which depends on the choice of units.

Therefore it has become common practice to consider the normalized sensitivity values, the

sensitivity matrix, S, as defined by Equation (17).

( ) ( )j

i

j

i

i

jkc

kc

ck

ijS lnln

δδ

δδ == (17)

The sensitivity coefficient Sij corresponds to the effect of changing kj upon ci. A

positive value of Sij indicates that an increase in the parameter kj results in a higher

predicted value of ci. The type of analysis based on Equations (16) and (17) is called local

119

sensitivity analysis because the parameter perturbation studied is quite small. The most

common software for analysis of and simulation with a detailed chemical kinetic

mechanism is the CHEMKIN-4 package. The package includes application codes for a

number of reactor types including perfectly-stirred reactors, plug flow reactors, IC engine

and laminar premixed flames. In the present work we focus on sensitivity analysis of 0-D

homogenous plug-flow reactor type IC engine combustion chamber using SENKIN module

developed by Lutz (Lutz et al., 1988).

In present work, the sensitivity analysis of four kinetic reaction models (mechanisms) was

carried out to identify which reaction is sensitive to formation of nitrogen containing

pollutants (as NO, NO2 & NH3).

5.4 Rate of Production Analysis and Sensitivity of Proposed Kinetic Mechanisms: The rate of production analysis of the each kinetic mechanism identified the

reactions involved in the formation and consumption of major pollutants. In this analysis,

absolute rate of production (ROP) coefficient and normalized rate of production

coefficients were determined by solving the equation (10) to equation (11) by the Direct

Staggered Methods for IC engine model for each of reaction in the mechanism. With

selected simulation conditions of combustion (as given in Table 5.1, Table 5.2 and Input

Key words) in natural gas fired IC engine, the total rate of production (mole/cm3-sec) of a

particular formed or destroyed was calculated by summation of production or consumption

rate in a particular reaction.

120

Table 5.1 Typical Engine Geometrical Input Parameters and Gas Mixture Composition

Table 5.2 Common Input Variables for Rate of Production Analysis and Sensitivity

Analysis (Local) of Kinetic Mechanisms

The rate-of-production tables are printed to the diagnostic output file to allow quick

identification of dominant reaction paths. For IC engine model in CHEMKIN, rate of

production data can be obtained through the Graphical Post-Processor.

Table 5.2a Key words Input for Rate of Production and Sensitivity Analysis of Kinetic Mechanisms

For Rate of Production Analysis For Local Sensitivity Analysis

ICEN ! Internal Combustion Engine ICEN ! Internal Combustion Engine

TRAN ! Transient Solver TRAN ! Transient Solver

EQUI 1.0 ! Equivalence Ratio EQUI 1.0 ! Equivalence Ratio

PRES 2.24551668 ! Pressure (atm) PRES 2.24551668 ! Pressure (atm)

TEMP 1573.15 ! Temperature (K) TEMP 1573.15 ! Temperature (K)

CMPR 10.51 ! Engine Compression Ratio CMPR 10.51 ! Engine Compression Ratio

Sr. No

Engine Geometrical Input Parameters Initial Gas Mixture (CNG composition), Mole Fraction

Parameter (unit) Value Component Mole Fraction

1 Cylinder volume (cm3) 63 Methane (CH4) 0.8903 2 Displaced Volume (cm3) 56.52 Ethane (C2H6) 0.0105

3 Clearance Volume (cm3) 6.48 Propane (C3H8) 0.027

4 Cylinder Diameters (cm) 14.67 Butane (C4H10) 0.0017

5 Crank to Connecting rod ratio 1.632 Nitrogen (N2) 0.072

6. Combustion Starting Crank Angle

-142° Carbon Dioxide (CO2)

0.026

Sr. No Operating Parameter Value

1 Equivalence Ratio (F/A) 1.0

2 Initial Inlet Temperature 1500 °C & 4000 °C

3 Initial Inlet Pressure 1.0 atm

4 Engine Speed 3000 rpm

5 Starting Crank Angle -142°

121

DEG0 -142.0 ! Starting Crank Angle

(degrees)

DEG0 -142.0 ! Starting Crank Angle

(degrees)

LOLR 1.632 ! Engine Connecting Rod to

Crank Radius Ratio

LOLR 1.632 ! Engine Connecting Rod to

Crank Radius Ratio

RPM 2000.0 ! Engine Speed (rpm) RPM 2000.0 ! Engine Speed (rpm)

VOLD 63.0 ! Engine Cylinder VOLD 63.0 ! Engine Cylinder

Displacement Volume (cm3) Displacement Volume (cm3)

CPROD CO2 ! Complete-Combustion

Products

CPROD CO2 ! Complete-Combustion

Products

CPROD H2O ! Complete-Combustion

Products

CPROD H2O ! Complete-Combustion

Products

CPROD N2 ! Complete-Combustion Products CPROD N2 ! Complete-Combustion Products

SDIR ! Staggered Direct Method TIME 0.043 ! End Time (sec)

DELT 0.01 ! Time Interval for Printing (sec)

LSEN ! Local Sensitivity Method

ASEN CO ! A-factor Sensitivity

ASEN CO2 ! A-factor Sensitivity

ASEN H2O ! A-factor Sensitivity

ASEN NO ! A-factor Sensitivity

ASEN NO2 ! A-factor

END

5.4.1 Mechanism-I (Complete Detailed Mechanism):

This mechanism consists of 935 reactions and contains 185 species. Mostly the

reactions include Unimolecular initiations, Bimolecular initiations, Additions, Additions

with oxygen, Isomerizations, Beta-scissions, Decompositions to o-rings, Oxidations,

Branching, Metatheses, Combinations etc. More detail about the mechanism is given in

Chapter-3 and Annexure-I.

Mechanism-I was analyzed for the formation of nitrogen containing pollutants (NO, NO2

and NH3) and carbon monoxide (CO). The total rate of production of each pollutants was

122

plotted versus the crank rotation angle and is shown in Figure 5.1 to Figure 5.3 for CO,

NO, NO2 and NH3 respectively.

Figure 5.1. Variation of Rate of Production of CO at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

Figure 5.2 Variation of Rate of Production of NO at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

123

Figure 5.3 Variation of Rate of Production of NO2 at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

Figure 5.4 Variation of Rate of Production of NH3 at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

124

Table 5.3 Rate of Production Coefficients of Reactions Contributing in Formation of Pollutants in Mechanism-I

Pollutants Combustion Temperature

Reaction Normalized Rate of

Production Coefficient

Absolute Rate of Production Coefficient

(MOLES/CC-SEC)

Ref. No in Mechanism-I

as per Annexure-I

CO

1500 K

CO+N2O<=>CO2+N2 0.139 4.8561E-15 R-782.

CO2+N<=>NO+CO 0.740 2.5881E-14 R- 783.

HNCO+M<=>NH+CO+M 0.122 4.2585E-15 R- 870

NCO+M<=>N+CO+M -1.000 -1.8197E-17 R- 934

4000 K NCO+M<=>NH+CO+M 0.943 1.1707E-02 R-870

OH+NCO<=>NO+CO+H 0.043 5.3769E-04 R- 906

NCO+M<=>N+CO+M -0.985 -1.3061E-02 R- 934

NO

1500 K NO+H=>N+OH -0.078 -1.5128E-08 R- 790

NO+M<=>N+O+M 1.000 4.4104E-04 R- 811

HNO+M<=>H+NO+M 0.916 1.7836E-07 R- 932

4000 K

NO+H=>N+OH -0.862 -8.4253E+00 R-790

N+OH=>NO+H 0.660 7.1727E+00 R-791

NO+N=>N2+O -0.130 -1.2745E+00 R-802

N2+O=>NO+N 0.159 1.7317E+00 R- 803

NO+M<=>N+O+M 0.136 1.4788E+00 R-811

HNO+M<=>H+NO+M 0.041 4.4114E-01 R-932.

NO2

1500 K

NO+HO2<=>NO2+OH 0.082 ( 9.9119E-11) R-799

NO2+O<=>NO+O2 0.014 ( 1.6444E-11) R-814

NO2+NH<=>N2O+OH -0.038 (-3.8444E-22) R-818

NO2+NH2<=>N2O+H2O -0.617 (-6.1703E-21) R-819

NO2+M<=>NO+O+M 0.904 ( 1.0982E-09) R-821

4000 K NO2+H<=>NO+OH 0.999 ( 3.2671E-02) R-813

NO2+M<=>NO+O+M -1.000 (-3.2683E-02) R-821

NH3

1500 K NH3+OH<=>NH2+H2O -1.000 (-6.4979E-11) R-833

NH3(+M)<=>NH2+H(+M) 0.864 ( 2.6102E-04) R-836

NH3+M<=>NH+H2+M 0.136 ( 4.0930E-05) R-837

4000 K NH3(+M)<=>NH2+H(+M) -1.000 (-2.6791E-02) R-836

NH3+M<=>NH+H2+M 0.994 ( 2.6797E-02) R-837

Each of plots shows the trend of formation or destruction of each pollutant during the

engine cycle. The reactions which contribute the production of each pollutant dominate

during the combustion phase and destruction reactions proceed after the end of the

125

combustion and star of expansion or power stroke during which a fall in the temperature

was happened. We can also observe the variation in behavior of formation and destruction

of each specie with change in the temperature as shown in the plots of 1500 K and 4000 K.

These are extreme temperature observed experimentally during the start and end of

combustion process. These deviation due temperature is controlled by the kinetics and this

can be seen from the reactions given Table 5.3. According to the data given in Table 5.3, in

CO formation reactions, the reaction; CO2+N<=>NO+CO produce maximum CO

concentration as dictated by the normalized rate of production coefficient at 1500 K while

at temperature of 4000 K, NCO+M<=>NH+CO+M, contribute the maximum to CO

formation in combustion chamber. In case of NO formation, two reactions (i)

NO+M<=>N+O+M & (ii) HNO+M<=>H+NO+M are predicted to dominate the

formation of nitric oxide in combustion chamber at 1500 K and at temperature 4000 K, the

reaction, N+OH=>NO+H contribute the maximum in the formation of NO. Nitrogen

dioxide (NO2) is produced by the reactions NO2+M<=>NO+O+M & NO2+H<=>NO+OH

at temperature of 1500 K and 4000 K respectively.

The local sensitivity analysis of complete kinetic model (Mechanism-I) resulted in

identification of reactions rates of the proposed reaction model towards the pollutants

species formed due the combustion in IC engine. In this analysis, the normalized sensitivity

coefficients were calculated for pollutants species (CO, NO, NO2 & CO2) and determined

the important reactions of reaction rates show the sensitivity. As mentioned earlier that this

mechanism consists of 185 species, the calculations of sensitivity coefficients are possible

by the SENKIN but the computation time increased exponentially and required CPU

memory. The sensitivity coefficients are visualized by the sensitivity-bar plot as shown in

Figure 6.5 to 6.9 for CO, CO2, NO, NO2, and NH3 respectively for 1500 K and 4000 K. In

126

these plots, the positive value of normalized sensitivity coefficients of specie indicates that

concentrations of that specie show strong dependency towards that reaction rate.

According to Figure 5.5, CO concentrations show sensitivity towards the following

important reactions given with decreasing order (according to lowering value of sensitivity

coefficient); CO2+N<=>NO+CO, N2+O=>NO+N, NO+H=>N+OH at both temperatures.

Similarly, in Figure 5.6, sensitivity of CO2 concentrations towards important

reactions at 1500 K and 4000 K. According to this plot, the CO2 concentrations shows

sensitivity towards N+OH=>NO+H at 1500 K and CO2+N<=>NO+CO at 4000 K.

For nitrogen containing pollutants i.e. NO, NO2 & NH3, sensitivity bar-plots are shown in

Figure 5.7 to 5.9 for 1500 K and 4000 K. According to these plots, the concentrations of

NO, NO2, and NH3 show the positive sensitivity towards rates of following reactions;

For Nitric Oxide (NO); N2+O=>NO+N at 1500 K and reactions NO+N=>N2+O,

N2+O=>NO+N at 4000 K.

For Nitrogen dioxide (NO2); N2+O=>NO+N at 1500 K and reaction with lowering

sensitivity are NO2+M<=>NO+O+M NO+N=>N2+O at 4000 K. The first reaction

is 3rd body reaction showed greater sensitivity at 4000 K.

For Ammonia (NH3); N2+O=>NO+N at 1500 K and two reactions

N2+O=>NO+N, N+OH=>NO+H at 4000 K

127

Figure 5.5 CO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-I in

IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitivity Coefficient-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

H2O2(+M)=>2R2OH(+M)

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

NO2+M<=>NO+O+M

O+NH<=>N+OH

O+NH<=>NO+H

OH+NH<=>HNO+H

B

Normalized Logrithmic Sensitivity Coefficient-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

R1H+R2OH+M<=>H2O+M

H2O2(+M)=>2R2OH(+M)

H2O2+R1H<=>H2O+R2OH

C2H3CHOZ+R1H<=>C2H4Z+R5CHO

O2+N<=>NO+O

CO+N2O<=>CO2+N2

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

O+NH<=>N+OH

O+NH<=>NO+H

OH+NH<=>HNO+H

A

128

Figure 5.6 CO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-I in

IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitvity Coefficient-0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15

O2+N<=>NO+O

CO2+N<=>NO+CO

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N A

Normalized Logrithmic Sensitvity Coefficient-0.12 -0.09 -0.06 -0.03 0 0.03 0.06 0.09 0.12 0.15 0.18 0.21

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

H+NH<=>N+H2

O+NH<=>NO+H

O+HNO<=>OH+NO

OH+NH<=>HNO+H

OH+HNO<=>NO+H2O

B

129

Figure 5.7 NO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-I in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitvity Coefficient-0.6 -0.4 -0.2 0 0.2 0.4 0.6

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

NO2+O<=>NO+O2

H+NH<=>N+H2A

Normalized Logrithmic Sensitvity Coefficient-0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

NO2+O<=>NO+O2

H+NH<=>N+H2

O+NH<=>NO+H

OH+NH<=>HNO+H B

130

Figure 5.8 NO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-I in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitvity Coefficient-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5

C2H3CHOZ+R4CH3=>CH4+.COC2H3Z

C2H4Z+M<=>C2H2T+H2+M

R5CHO+M<=>R1H+B2CO+M

O2+N<=>NO+O

CO2+N<=>NO+CO

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

HNO+M<=>H+NO+M A

Normalized Logrithmic Sensitvity Coefficient-0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

C2H3CHOZ+R1H<=>C2H4Z+R5CHO

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

NO2+O<=>NO+O2

NO2+M<=>NO+O+M

H+HNO<=>H2+NO

O+NH<=>N+OH

O+NH<=>NO+H

O+HNO<=>OH+NO

OH+NH<=>HNO+H

B

131

Figure 5.9 NH3 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-I in

IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitvity Coefficient-0.5-0.45-0.4-0.35-0.3-0.25-0.2-0.15-0.1-0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

O2+NH<=>HNO+OCO2+N<=>NO+CO

NO+H=>N+OHN+OH=>NO+HNO+N=>N2+ON2+O=>NO+N

NO+NH<=>N2+OHNO+NH<=>N2O+HNO2+O<=>NO+O2

NO2+M<=>NO+O+MNH3+O=>NH2+OH

NH3+OH<=>NH2+H2OH+NH<=>N+H2

H+NH2<=>NH+H2H+NNH<=>N2+H2H+HNO<=>H2+NO

O+NH<=>NO+HO+NH2<=>NH+OHO+NH2<=>HNO+HO+NNH<=>NH+NOOH+NH<=>HNO+HOH+NH2=>O+NH3

OH+NH2<=>NH+H2OOH+NNH<=>N2+H2O

OH+HNO<=>NO+H2ONH2+M<=>NH+H+M

HNO+M<=>H+NO+M

B

Normalized Logrithmic Sensitvity Coefficient-0.45 -0.4 -0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

O2+N<=>NO+OO2+NH<=>HNO+OCO2+N<=>NO+CO

NO+H=>N+OHN+OH=>NO+HNO+N=>N2+ON2+O=>NO+N

NO+NH<=>N2+OHNO+NH<=>N2O+HNO2+O<=>NO+O2

NO2+M<=>NO+O+MNH3+H<=>NH2+H2NH3+O=>NH2+OH

NH3+OH<=>NH2+H2OH+HNO<=>H2+NO

O+NH<=>N+OHO+NH<=>NO+H

O+NH2<=>NH+OHO+NH2<=>HNO+HO+NNH<=>NH+NOOH+NH<=>HNO+HOH+NH2=>O+NH3

OH+NH2<=>NH+H2OOH+NNH<=>N2+H2O

OH+HNO<=>NO+H2ONH2+M<=>NH+H+M

HNO+M<=>H+NO+M

A

132

5.4.2 Mechanism-II

This kinetic reaction scheme consists of 792 elementary reactions and 153 species.

The reactions scheme contains the reactions feasible under high temperature environment.

More detail about the mechanism is given in Chapter-3 and Annexure-I.

The rate of production analysis of this kinetic model was studied using the

simulation conditions as given in Table 5.1 and Table 5.2 for modeling the combustion in

natural gas fired IC engine using Chemkin 4.1.1 module. The model analyses each

species/radical present in the mechanism schemes but we presently focused on the

identification of reaction contributing the formation of various pollutants such as, Oxide of

nitrogen (NOx as NO & NO2), ammonia (NH3) and carbon monoxide (CO). As mentioned

earlier that Chemkin 4.1.1 solve equation (10) to equation (12) to determine the absolute

rate of production and normalized rate of production coefficients for each elementary

reaction involved in the production and destruction of each specie present in the

Mechanism-II. The ROP analysis results are shown in Figure 5.10 to 5.13 and rate o

production coefficients (both absolute & normalized) for the reactions involved in the

formation pollutants is given in Table 5.4.

The ROP analysis shows that three reactions (i) H+NCO<=>NH+CO (ii)

O+NCO<=>NO+CO (iii) OH+NCO<=>NO+CO+H contribute the formation of CO during

the combustion process at 1500 K. When combustion was simulated at 4000 K, ROP

analysis predicts that only the reaction, CO2+N<=>NO+CO major producer of the carbon

monoxide As indicated in Chapter-4, the simulation results show the early start of

combustion. Over all the production rate of CO is plotted versus the crank rotation angle

during the engine cycle. We can observe the variation in pattern of production rate profiles

at 1500 K and 4000 K which is dictated by the reactions involved in CO production at both

selected temperatures ranges.

133

Figure 5.10 Variation of Rate of Production of CO at Extreme Temperatures of

T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

Figure 5.11 Variation of Rate of Production of NO at Extreme Temperatures of

T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

134

Figure 5.12 Variation of Rate of Production of NO2 at Extreme Temperatures of

T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

Figure 5.13 Variation of Rate of Production of NH3 at Extreme Temperatures of

T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

135

Table 5.4 Rate of Production Coefficients of Reactions Contributing in Formation of

Pollutants in Mechanism-II Pollutants Combustion

Temperature Reaction Normalized

Rate of Production Coefficient

Absolute Rate of Production Coefficient

(MOLES/CC-SEC)

Ref. No in Mechanism-I

as per Annexure-I

CO

1500 K

CO+N2O<=>CO2+N2 -0.013 -2.2866E-05 R-640.

CO2+N<=>NO+CO 0.094 1.8043E-04 R-641

HCN+O<=>NH+CO 0.044 8.4562E-05 R-708.

HNCO+H<=>NH2+CO 0.119 2.2865E-04 R-718.

HNCO+M<=>NH+CO+M -0.025 (-4.5230E-05) R-728.

H+NCO<=>NH+CO 0.304 ( 5.8178E-04) R-737.

O+CN<=>CO+N -0.017 (-3.0551E-05) R-753.

O+NCO<=>NO+CO 0.290 ( 5.5662E-04) R-754

OH+NCO<=>NO+CO+H 0.138 ( 2.6440E-04) R-763

NCO+M<=>N+CO+M -0.945 (-1.7148E-03) R-791

4000 K

CO+N2O<=>CO2+N2 -0.024 (-1.1525E-09) R-640.

CO2+N<=>NO+CO 0.792 ( 1.7272E-07) R-641

HNCO+H<=>NH2+CO 0.011 ( 2.2953E-09) R-718

HNCO+M<=>NH+CO+M -0.013 (-6.0831E-10) R-728

H+NCO<=>NH+CO 0.061 ( 1.3270E-08) R-737

O+CN<=>CO+N -0.065 (-3.1224E-09) -753.

O+NCO<=>NO+CO 0.110 ( 2.4050E-08) R-754.

OH+NCO<=>NO+CO+H 0.022 ( 4.7874E-09) R-763.

NCO+M<=>N+CO+M -0.896 (-4.3075E09- R-791

NO

1500 K

NO+H=>N+OH -0.642 (-3.6909E+00) R-648

N+OH=>NO+H 0.670 ( 3.3234E+00) R-649

NO+N=>N2+O -0.349 (-2.0050E+00) R-660

N2+O=>NO+N 0.334 ( 1.9444E+00) R-661

O+NH<=>NO+H 0.024 ( 1.4098E-01) R-746

HNO+M<=>H+NO+M 0.033 ( 1.9272E-01) R-789

4000 K

NO+H=>N+OH -0.707 (-1.4219E-03) R-648

N+OH=>NO+H 0.877 ( 1.3612E-03) R-649

NO+N=>N2+O -0.289 (-5.8004E-04) R-660.

N2+O=>NO+N 0.386 ( 5.7451E-04) R-661

O+NH<=>NO+H 0.418 ( 3.6036E-05) R-746

NO2 1500 K NO+HO2<=>NO2+OH -0.064 (-3.5570E-03) R-657

NO2+H<=>NO+OH -0.460 (-2.5433E-02) R-671

NO2+O<=>NO+O2 -0.475 (-2.6270E-02) R-672

136

NO2+M<=>NO+O+M 1.000 ( 4.8893E-02) R-679

4000 K

NO+HO2<=>NO2+OH -0.035 (-2.7593E-07) R-657

NO2+H<=>NO+OH 0.491 ( 1.5245E-06) R-671

NO2+O<=>NO+O2 -0.965 (-7.7183E-06) R-672.

NO2+M<=>NO+O+M 0.809 ( 6.4378E-06) R-679

NH3

1500 K

NH3+H<=>NH2+H2 0.085 ( 8.9859E-05) R-689.

NH3+O=>NH2+OH -0.792 (-8.3998E-04) R-690

NH3+OH<=>NH2+H2O -0.208 (-2.2044E-04) R-691

NH3(+M)<=>NH2+H(+M) 0.120 ( 1.2675E-04) R-694

NH3+M<=>NH+H2+M 0.016 ( 1.7370E-05) R-695

OH+NH2=>O+NH3 0.776 ( 8.1789E-04) R-757

4000 K

NH3+O=>NH2+OH -0.863 (-3.6189E-08) R-690.

NH3+OH<=>NH2+H2O -0.137 (-5.7240E-09) R-691.

NH3(+M)<=>NH2+H(+M) 0.049 ( 2.0543E-09) R-694

OH+NH2=>O+NH3 0.948 ( 3.9727E-08) R-757

Following two reactions (i) N+OH=>NO+H, (ii) N2+O=>NO+N are involved in formation

on nitric oxide (NO) in IC engine combustion chamber at 1500 K while three reactions (i)

N+OH=>NO+H, (ii) N2+O=>NO+N and (iii) O+NH<=>NO+H are major contributor in

the formation of NO while in reaction; NO+H=>N+OH, NO is consumed. Other

component of NOx is nitrogen dioxide (NO2) which is formed by the reversible reaction

NO2+M<=>NO+O+M both at 1500 K and 4000 K.

The simulation studies shows that ammonia (NH3) is also formed during the combustion of

CNG fired IC engine. The ROP analysis of the mechanism at two ranges of temperature

1500 K and 4000 K shows that about five reaction involved in the formation and

consumption of NH3 at 1500 K and the reaction “OH+NH2=>O+NH3” is major producer of

ammonia. Each plot of Figure 5.10 to 5.13 shows that the formation reactions occurred

during the combustion process and consumption reactions dominate in the start or during

the expansion phase which indicate that each pollutant formation sustain at high

temperature while its production is lowered as the temperature in the chamber is decreased.

137

In the sensitivity analysis high temperature kinetic model, the reactions were identified

which due to which the concentrations of major pollutants species including NO, NO2,

NH3, CO and CO2 were affected. In other words, we identified the reactions which

significantly affect the output concentrations of pollutants species during the combustion

process of the IC engine cycle. In this section, we have plotted sensitivity bar plots for CO,

CO2, NO, NO2 and NH3 as shown in Figure 5.14 to 5.18 for two cases (Case-A for T=1500

K and Case-B for T=4000 K) respectively. Figure 5.14 shows sensitivity of CO

concentrations towards the most important reaction rates when combustion of natural gas in

IC engine is modeled with Mechanism-II. This bar-plot illustrate that the dominant

reaction is CO2+N<=>NO+CO for two case studies at temperature of 1500 K and 4000 K.

The sensitivity versus time plots shows that the reaction CO+N2O<=>CO2+N2 (R-640) is

important during the initiation of the combustion at temperature of 1500 K and

CO+N2O<=>CO2+N2 shows sensitivity towards CO concentrations at 4000 K.

Similarly, the nitric oxide concentrations shows more sensitivity towards the reaction

N+OH=>NO+H and the reaction N2+O=>NO+N significantly affect the NO concentrations

during the initiation steps as concluded by the sensitivity versus time plots at the 1500 K.

While the reaction N2+O=>NO+N affect the nitric oxide concentrations significantly at

4000 K as shown in Figure 5.16 of NO sensitivity bar-plots. The N2+O=>NO+N The

nitrogen dioxide (NO2) concentration is strongly influenced by the reaction

NO+H=>N+OH and N2+O=>NO+N at temperature of 1500 K and 4000 K, respectively.

The ammonia (NH3) concentrations are strongly influenced by the rates of NO+N=>N2+O

during the combustion of natural gas IC engine with kinetic model at T=1500 K and when

combustion is simulated at 4000 K the NH3 concentrations were shows strong dependence

on the rates of reactions with order of NO+N=>N2+O and N+OH=>NO+H. The sensitivity

(as normalized sensitivity coefficients) bar-plot is shown in Figure 5.18.

138

Figure 5.14 CO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-II in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized LOgrithmic Sensitivity Coefficient-0.4 -0.2 0 0.2 0.4 0.6 0.8 1

2R2OH(+M)=>H2O2(+M)

H2O2+R1H<=>H2O+R2OH

H2O2+R2OH<=>H2O+R3OOH

H2O2(+M)=>2R2OH(+M)

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

OH+NH<=>N+H2O

A

Normalized Logrithmic Sensitivity Coefficient-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

C2H4Z+M<=>C2H2T+H2+M

R1H+R2OH+M<=>H2O+M

2R2OH(+M)=>H2O2(+M)

H2O2(+M)=>2R2OH(+M)

H2O2+R1H<=>H2O+R2OH

O2+N<=>NO+O

CO+N2O<=>CO2+N2

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

O+NH<=>N+OH

O+NH<=>NO+H

B

139

Figure 5.15 CO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-II in IC engine at equivalence ratio =1.0 and engine speed at 3000 K when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitivity Coefficient-0.06 -0.04 -0.02 0 0.02 0.04

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N A

Normalized Logrithmic Sensitivity Coefficient-0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15

O2+N<=>NO+O

CO2+N<=>NO+CO

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N B

140

Figure 5.16 NO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-II in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitivty Coefficient-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

NO2+O<=>NO+O2 A

Normalized Logrithmic Sensitivity Coefficient-0.6 -0.4 -0.2 0 0.2 0.4 0.6

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

NO2+O<=>NO+O2 B

141

Figure 5.17 NO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-II

in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitivity Coefficient-0.45 -0.4 -0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

+OH=>NO+H

NO+N=>N2+O

NO2+O<=>NO+O2

OH+NH<=>HNO+H A

Normalized Logrithmic Sensitivty Coefficient-0.45-0.4-0.35-0.3-0.25-0.2-0.15-0.1-0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

R5CHO+M<=>R1H+B2CO+M

R5CHO+M<=>R1H+B2CO+M

C2H3CHOZ+R1H<=>C2H4Z+R5CHO

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

NO+N=>N2+O

N2+O=>NO+N

NO2+O<=>NO+O2

H+NH<=>N+H2

O+NH<=>NO+H

B

142

Figure 5.18 NH3 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-II in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

5.4.3 Mechanism-III It is low temperature mechanism and consists of 864 elementary reactions. This low

temperature reaction model was used to simulate combustion in IC engine using Chemkin

Normalized Logrithmic Sensitvity Coefficient-0.06 -0.04 -0.02 0 0.02 0.04

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N A

Normalized Logrithmic Sensitivity Coefficient-0.125 -0.1 -0.075 -0.05 -0.025 0 0.025 0.05 0.075

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

O+NH<=>NO+H

OH+HNO<=>NO+H2O B

143

4.1.1. Although the reaction model exhibit the discrepancies as discussed in Chpater-4 but

the model succeeded in predicting the pressure, temperature and emission profiles for CO,

NOx (as NO & NO2) and ammonia (NH3). In current study, model was analyzed to

determine the reactions contribute the formation of pollutants particularly CO, NO, NO2 (as

NOx) and NH3 with ROP analysis.

Total rate of production, absolute rate of production coefficient and normalized rate of

production was determined for each of the reaction step of the Mechanism-III. Total rate of

production denote the net rate of production of a species from each of reaction, the results

of ROP analysis of Mechanism-III are shown in Figure 5.19 to 5.22 for formation of CO,

NO, NO2 and NH3 respectively. The total ROP of each pollutant was plotted versus crank

rotation angle which presented the picture of formation of specie during the whole engine

cycle. Figure 5.19 shows that the formation profile of CO at low and high temperature

(1500 K & 4000 K) is similar but varied in the net rate of production at each temperature.

Significant variation in ROP profiles for NO, NO2 and NH3 at each temperature as shown

in Figure 5.19, Figure 5.20 and Figure 5.21 respectively. Table 5.5 shows that reactions

involved in the formation and consumption of each pollutant varied in the types of

reactions and their contribution to the net rate of production.

The following reactions (i) CO2+N<=>NO+CO (0.713), (ii) O+NCO<=>NO+CO (0.583)

and (iii) OH+NCO<=>NO+CO+H (0.285) contribute significantly in the formation of

CO at 1500 °C during the combustion of natural gas in IC engine simulated with

Mechanism-III while reaction NCO+M<=>N+CO+M (0.931), CO2+N<=>NO+CO (0.494)

and O+NCO<=>NO+CO (0.296) at 4000 K. The normalized rate of production coefficients

given with each of reaction explain the reason of deviation in the profiles shown above.

Similarly, the predicted formation of NO at 1500 K is controlled by the reaction of

N+OH=>NO+H (0,826) and at 4000 K, the reactions N+OH=>NO+H (0.588) &

144

Figure 5.19 Variation of Rate of Production of CO at Extreme Temperatures of T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

Figure 5.20 Variation of Rate of Production of NO at Extreme Temperatures of

T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

145

Figure 5.21. Variation of Rate of Production of NO2 at Extreme Temperatures of

T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

Figure 5.22. Variation of Rate of Production of NH3 at Extreme Temperatures of

T=1500 K and T=4000 KC in IC engine for Equivalence Ratio ≈1.0

146

Table 5.5 Rate of Production Coefficients of Reactions Contributing in Formation of Pollutants in Mechanism-III

Pollutants Combustion Temperature

Reaction Normalized Rate of

Production Coefficient

Absolute Rate of Production

Coefficient (Mole/cm3-sec)

Ref. No in Mechanism-I

as per Annexure-I

CO

1500 K

CO+N2O<=>CO2+N2 -0.032 (-4.9372E-08) R-711

CO2+N<=>NO+CO 0.713 (1.1177E-06) R-712

HCN+O<=>NH+CO 0.020 ( 6.5218E-09) R-779

HNCO+H<=>NH2+CO 0.056 ( 1.8666E-08) R-789

H+NCO<=>NH+CO 0.250 ( 8.2966E-08) R-808

O+NCO<=>NO+CO 0.583 ( 1.2714E-07) R-826

OH+NCO<=>NO+CO+H 0.285 ( 9.4798E-08) R-835

NCO+M<=>N+CO+M -0.246 (-3.8567E-07) R-863

4000 K

CO2+N<=>NO+CO 0.494 ( 1.4184E-04) R-712

NO+C<=>CO+N 0.011 ( 3.1947E-06) R-718

HCN+O<=>NH+CO 0.024 ( 6.7588E-06) R-779

HNCO+H<=>NH2+CO 0.043 ( 1.2323E-05) R-789

HNCO+M<=>NH+CO+M -0.017 (-2.5264E-06) R-799

H+NCO<=>NH+CO 0.187 ( 5.3744E-05 R-808

O+CN<=>CO+N -0.049 (-7.1874E-06) R-825.

O+NCO<=>NO+CO 0.296 ( 5.6425E-05) R-826

OH+NCO<=>NO+CO+H 0.043 ( 1.2272E-05) R-835

NCO+M<=>N+CO+M 0.931 (1.3538E-04) R-863

NO

1500 K

O2+N<=>NO+O 0.022 ( 8.3032E-05) R-704

NO+H=>N+OH -0.667 (-2.5746E-03) R-719

N+OH=>NO+H 0.826 ( 2.3769E-03) R-720

NO+N=>N2+O -0.310 (-1.1951E-03) R-731

N2+O=>NO+N 0.310 ( 1.1781E-03) R-732

NO2+O<=>NO+O2 0.014 ( 5.4731E-05) R-743

O+NH<=>NO+H 0.012 ( 4.4382E-05) R-818

4000 K

NO+H=>N+OH -0.638 (-8.3624E-01) R-719

N+OH=>NO+H 0.588 ( 7.7194E-01) R-720

NO+N=>N2+O -0.358 (-4.6863E-01) R-731

N2+O=>NO+N 0.351 ( 4.6100E-01) R-732

O+NH<=>NO+H 0.029 ( 3.7581E-02) R-818

HNO+M<=>H+NO+M 0.012 ( 1.5735E-02) R-861

NO2 1500 K NO+HO2<=>NO2+OH -0.086 (-5.1795E-06) R-728

NO2+H<=>NO+OH 0.548 ( 3.6825E-05) R-742

147

NO2+O<=>NO+O2 -0.913 (-5.4731E-05) R-743

NO2+M<=>NO+O+M 0.452 ( 3.0349E-05) R-750

4000 K

NO+HO2<=>NO2+OH -0.033 (-1.9877E-04) R-728

NO2+H<=>NO+OH -0.496 (-2.9455E-03) R-742

NO2+O<=>NO+O2 -0.470 (-2.7917E-03) R-743

NO2+M<=>NO+O+M 1.000 ( 5.7020E-03) R-750

NH3

1500 K

NH3+H<=>NH2+H2 0.296 ( 1.6587E-07) R-760

NH3+O=>NH2+OH -0.734 (-4.0985E-07 R-761

NH3+OH<=>NH2+H2O -0.266 (-1.4860E-07) R-762

OH+NH2=>O+NH3 0.695 ( 3.8921E-07) R-829

4000 K

NH3+H<=>NH2+H2 -0.100 (-6.1830E-06) R-760

NH3+O=>NH2+OH -0.791 (-4.8987E-05) R-761

NH3+OH<=>NH2+H2O -0.109 (-6.7396E-06) R-762

NH3(+M)<=>NH2+H(+M) 0.161 ( 9.9204E-06) R-765

NH3+M<=>NH+H2+M 0.011 ( 6.8855E-07) R-766

OH+NH2=>O+NH3 0.826 ( 5.1000E-05) R-829

N2+O=>NO+N (0.351) are identified which significantly effect the formation of nitric

oxide in IC engine combustion chamber. The nitrogen dioxide (NO2) formation is

controlled by the similar type of reactions at both of the temperature rages i.e., 1500 K and

4000 K but with different level of contribution as demonstrated by the determined values of

normalized rate of production coefficients for each of reaction involve given in Table 5.5.

The predicted formation of ammonia is controlled by similar type of reactions and

following reaction OH+NH2=>O+NH3 contribute significantly at both of the temperature

ranges. At 4000 K, additional reaction NH3+M<=>NH+H2+M (0.011) is predicted by the

ROP analysis contribute in the formation of NH3 during the combustion process in the

engine cycle.

The sensitivity-bar plots for CO, CO2, NO, NO2, and NH3 are shown in Figure 5.23

to 6.27 respectively. The sensitivity analysis of this low temperature oxidation mechanism

of natural gas in IC engine was carried out for two temperatures i.e. Case-A when T=1500

K and Case-B when T=4000 K. Each plot illustrates the reactions influencing the

148

concentration of each above specie during the combustion in the IC engine under the

simulation conditions given in Table 5.1-Table 5.2a.

In Figure 5.23, the sensitivity of CO concentrations towards the most important reaction

rates is illustrated. This bar-plot predicts that the most dominant reaction is

CO2+N<=>NO+CO at T=1500 K and at 4000 K but as clear from the plot, the same

reaction shows higher sensitivity at 1500 K for CO concentrations. The CO2 sensitivity bar

plot predicts that the formation of CO2 is greatly influenced by the reaction NO+N=>N2+O

at 1500 K and N+OH=>NO+H NO+N=>N2+O at T=4000 K. The sensitivity versus time

plot indicate that the reaction H+NNH<=>N2+H2 plays important role during the initiation

steps.

The NO sensitivity bar-plots shows the important reactions at T=1500 K and T=4000 K as

shown in Figure 5.25. According to this plot, the nitric oxide (NO) concentrations are

dependent of the rate of the following reactions at;

T=1500 K N+OH=>NO+H (R-720)

N2+O=>NO+N (R-732)

and at =4000 K,

N2+O=>NO+N (R-732)

N+OH=>NO+H (R-20)

O2+N<=>NO+O (R-704)

CO2+N<=>NO+CO (R-712)

But in the both cases, the reaction R-732 of Mechanism-III shows dominant effect on the

NO concentrations and this reaction also greatly affect the NO2 & NH3 concentrations as

illustrated in sensitivity bar-plot is shown in Figure 5.26 and Figure 5.27 respectively. The

149

degree of effect of the reaction R-732 is different for each of the nitrogen containing

pollutant as discussed above.

Figure 5.23 CO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-III

in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 k and (B) T=4000 k

Nomalized Logrithmic Sensitvity Coefficient-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

R1H+R2OH+M<=>H2O+M

H2O2+R2OH<=>H2O+R3OOH

O2+N<=>NO+O

CO+N2O<=>CO2+N2

CO2+N<=>NO+CO

NO+H=>N+OH

NO+N=>N2+O

N2+O=>NO+N

NO2+O<=>NO+O2

N2O+O<=>N2+O2

O+NH<=>N+OH

O+NH<=>NO+H

OH+NH<=>N+H2O

A

Normalized Logrithmic Sensitivity Coefficient-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

2R2OH(+M)=>H2O2(+M)

H2O2(+M)=>2R2OH(+M)

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

NO2+O<=>NO+O2

NO2+M<=>NO+O+M

O+NH<=>N+OH

O+NH<=>NO+H

OH+NH<=>HNO+H

OH+NH<=>N+H2O

B

150

Figure 5.24 CO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-III in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitivity Coefficient-0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08 0.1

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+NA

Normalized Logrithmic Sensitivity Coefficient-0.125 -0.1 -0.075 -0.05 -0.025 0 0.025 0.05 0.075

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

OH+HNO<=>NO+H2O B

151

Figure 5.25 NO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-III in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitivity Coefficient-0.6 -0.4 -0.2 0 0.2 0.4 0.6

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+NA

Normalized Logrithmic Sensitivity Coefficient-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

NO2+O<=>NO+O2

H+NH<=>N+H2 B

152

Figure 5.26 NO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-III in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitivity Coefficient-0.45-0.4-0.35-0.3-0.25-0.2-0.15-0.1-0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

C2H3CHOZ+R1H<=>C2H4Z+R5CHO

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

NO2+O<=>NO+O2

H+NH<=>N+H2

O+NH<=>N+OH

A

Normalized Logrithmic Sensitvity Coefficient-0.45-0.4-0.35-0.3-0.25-0.2-0.15-0.1-0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

O2+N<=>NO+O

CO2+N<=>NO+CO

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

NO2+O<=>NO+O2

NO2+M<=>NO+O+M

H+NH<=>N+H2

O+NH<=>N+OH

O+NH<=>NO+H

OH+NH<=>HNO+H

B

153

Figure 5.27 NH3 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-III

in IC engine at equivalence ratio =1.0 and engine speed at 3000 rpm when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitvity Coefficient-0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

O2+N<=>NO+O

O2+NH<=>HNO+O

N2+O=>NO+N

NO+NH<=>N2+OH

NO+NH<=>N2O+H

NO2+O<=>NO+O2

NH3+H<=>NH2+H2

NH3+OH<=>NH2+H2O

H+NH2<=>NH+H2

O+NH<=>N+OH

O+NH<=>NO+H

O+NH2<=>NH+OH

O+NH2<=>HNO+H

OH+NH<=>HNO+H

OH+NH2=>O+NH3

OH+NH2<=>NH+H2O

OH+NNH<=>N2+H2O

OH+HNO<=>NO+H2O

A

Normalized Logrithmic Sensitivity Coefficient-0.45 -0.4 -0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

O2+N<=>NO+OO2+NH<=>HNO+OCO2+N<=>NO+CO

NO+H=>N+OHN+OH=>NO+HNO+N=>N2+ON2+O=>NO+N

NO+NH<=>N2+OHNO+NH<=>N2O+HNO2+O<=>NO+O2

NO2+M<=>NO+O+MNH3+H<=>NH2+H2NH3+O=>NH2+OH

NH3+OH<=>NH2+H2OH+HNO<=>H2+NO

O+NH<=>N+OHO+NH<=>NO+H

O+NH2<=>NH+OHO+NH2<=>HNO+HO+NNH<=>NH+NOOH+NH<=>HNO+HOH+NH2=>O+NH3

OH+NH2<=>NH+H2OOH+NNH<=>N2+H2O

OH+HNO<=>NO+H2ONH2+M<=>NH+H+M

HNO+M<=>H+NO+M

B

154

5.4.4 Mechanism-IV

This is automatically simplified mechanism consists of 208 elementary reactions

and 72 species. Mostly the reaction are of primary type including unimolecular initiations,

bimolecular initiations, beta-scissions, oxidations, branching, metatheses and

combinations.

The rate of production analysis of Mechanism-IV was carried out using the input variables

as given in Table 5.1 and Table 5.2 to identify the reactions of mechanism contributing the

formation of gaseous pollutants (NO, NO2, MH3 and CO). Normalized rate of production

coefficients of each reaction contribute in the formation of the pollutants.

The total rate of production (net value of absolute rate of production or consumption) of

each selected pollutants during the engine cycle and plotted versus crank rotation angle as

shown in Figure 5.28 to Figure 5.31 for CO, NO, NO2 and NH3 respectively.

Figure 5.28 Variation of Rate of Production of CO at Extreme Temperatures of

T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

155

Figure 5.29 Variation of Rate of Production of NO at Extreme Temperatures of

T=1500 °C and T=4000 °C in IC engine for Equivalence Ratio ≈1.0 Figure 5.30 Variation of Rate of Production of NO2 at Extreme Temperatures of

T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0

Crank rotation angle

Tota

l Rat

e of

Pro

duct

ion,

(mol

e/cm

3-se

c)

-150 -120 -90 -60 -30 0 30 60 90 120 150-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

T=1500 °C

Crank rotation angle

Tota

l Rat

e of

Pro

duct

ion,

(mol

e/cm

3-se

c)

-150 -120 -90 -60 -30 0 30 60 90 120 150-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

T=4000 °CK K

156

Figure 5.31 Variation of Rate of Production of NH3 at Extreme Temperatures of

T=1500 K and T=4000 K in IC engine for Equivalence Ratio ≈1.0 Table 5.6 Rate of Production Coefficients of Reactions Contributing in Formation of

Pollutants in Mechanism-IV Pollutants Combustion

Temperature Reaction Normalized

Rate of Production Coefficient

Absolute Rate of Production

Coefficient (Mole/cm3-sec)

Ref. No in Mechanism-I

as per Annexure-I

CO

1500 K HNCO+M<=>NH+CO+M 0.980 ( 3.9649E+00) R-141

OH+NCO<=>NO+CO+H 0.015 ( 6.0902E-02) R-177

NCO+M<=>N+CO+M -0.694 (-3.4886E+00) R-205

4000 K

NO+C<=>CO+N 0.056 ( 9.1808E-05) R-60

HCN+O<=>NH+CO -0.016 (-2.5078E-05) R-121

HNCO+M<=>NH+CO+M -0.893 (-1.3941E-03) R-141

O+CN<=>CO+N -0.088 (-1.3745E-04) R-167

OH+NCO<=>NO+CO+H 0.014 ( 2.3043E-05) R-177

N+NCO<=>N2+CO 0.019 ( 3.1427E-05) R-188

NCO+M<=>N+CO+M 0.907 ( 1.4943E-03) R-205

NO 1500 K

NO+H=>N+OH -0.742 (-2.3091E+00) R-61

N+OH=>NO+H 0.063 ( 2.0445E+00) R-62

NO+N=>N2+O -0.239 (-7.4298E-01) R-73

N2+O=>NO+N 0.028 ( 9.1988E-01) R-74

NO+M<=>N+O+M 0.905 ( 2.9235E+01) R-82

Crank rotation angle

Tota

l Rat

e of

Pro

duct

ion,

(mol

e/cm

3-se

c)

-150 -120 -90 -60 -30 0 30 60 90 120 150-6000

-4000

-2000

0

2000

4000

6000

8000

10000

12000

14000

16000

T=4000 °C

Crank rotation angle

Tota

l Rat

e of

Pro

duct

ion,

(mol

e/cm

3-se

c)

-150 -120 -90 -60 -30 0 30 60 90 120 150-20000

-15000

-10000

-5000

0

5000

10000

15000

20000

T=1500 °CK K

157

NO2+H<=>NO+OH -0.015 (-4.5446E-02) R-84

4000 K

NO+H=>N+OH -0.512 (-3.5391E-01) R-61

N+OH=>NO+H 0.712 ( 3.1293E-01) R-62

NO+N=>N2+O -0.186 (-8.1044E-02) R-73

N2+O=>NO+N 0.236 ( 8.3061E-02) R-74

NO+M<=>N+O+M 0.343 ( 2.0973E-01) R-82

NO2

1500 K NO2+H<=>NO+OH 1.000 ( 4.5446E-02) R-84

NO2+M<=>NO+O+M -1.000 (-4.5057E-02) R-92

4000 K NO2+H<=>NO+OH 0.999 ( 5.2207E-04) R-84

NO2+M<=>NO+O+M -1.000 (-5.2170E-04) R-92

NH3

1500 K NH3+O=>NH2+OH -0.088 (-6.4899E-09) R-103

NH3+OH<=>NH2+H2O -0.910 (-6.6873E-08) R-104

NH3<=>NH2+H 1.000 ( 1.1930E+01) R-107

4000 K NH3+O=>NH2+OH -1.000 (-2.5955E-10) R-103

NH3<=>NH2+H 1.000 ( 4.5557E-01) R-107

The total rate of production (mole/cm3-sec) was calculated at two rages of temperature of

1500 K and 4000 K. The effect of temperature variation on the contribution of each

reaction in emissions is clear (from the values of Normalized ROP coefficients) from the

formation and consumption profiles (Figure 5.28 to 5.31) for each pollutant. The variation

in pattern of each profile of both of the temperature ranges is correlated with the reactions

and their contribution to total rate of production. It is clear from each profile that the

formation of each pollutant occurs during combustion process after the compression stroke.

Table 5.6 shows the reactions involve din the formation or consumption of each pollutant at

1500 K and 4000 K and their normalized rate of production coefficients and absolute rate

of production coefficients. In the last column of the Table 5.6 shows the reference number

of the reaction designated in the Mechanism-IV as given in Annexure-I. According to data,

it is predicted that the reaction HNCO+M<=>NH+CO+M (0.98) significantly contribute

the formation of CO at 1500 K and the reaction NCO+M<=>N+CO+M (0.907) produce the

more CO at 4000 K. Similarly nitric oxide (NO) is formed from reactions

158

NO+M<=>N+O+M (0.905) and N+OH=>NO+H (0.712)of the mechanism-IV at 1500 K

and 4000 K respectively in the IC engine simulated under the given conditions. The only

reaction NO2+H<=>NO+OH take in the formation of other important component of NOx at

1500 K and 4000 K.

Now when the local sensitivity analysis of this automatically simplified kinetic model

(Mechanism-IV) carried out, we were able to identify the reactions of rates have influence

on the formation of gaseous pollutants including nitrogen containing compounds (NO, NO2

and NH3) and CO & CO2. The sensitivity bar-plot for each of the said pollutants is shown

in Figure 6.32 to 6.36 respectively for CO, CO2, NO, NO2 and NH3. In these plots,

normalized logarithmic sensitivity coefficients were calculated at the condition mentioned

for the each of the reaction step. The results were printed a notepad file by the SENKIN

using Direct Staggered Method modeled to solve equation (5) using the KEYWORDS

given in Table 5.2a.

In Figure 5.32, sensitivity of CO concentrations towards some important reaction rates is

shown. This plot illustrate that the dominant reactions are O2+N<=>NO+O

O2+CN<=>NCO+O for the formation of carbon monoxide in the combustion chamber of

IC engine at 1500 K and 4000 K with given specification in Table 5.2. These reactions

show positive sensitivity in the forwards direction. Similarly the CO2 sensitivity bar-plot

predicts that sensitivity of CO2 concentrations are greatly affected by the reactions at the;

AT T=1500 K;

NO+N=>N2+O (R-73)

HNCO+OH<=>NH2+CO2 (R-136)

And at T=4000 K

N+OH=>NO+H (R-62)

HNCO+OH<=>NH2+CO2 (R-136)

159

From the NO and NO2 sensitivity bar-plots, it is predicted that NO & NO2 concentrations

are dominantly affected by the rates of the following reactions at 1500 K and 4000 K;

• For Nitric Oxide (NO); the important reactions are; N+OH=>NO+H (R-62)

and N2+O=>NO+N (R-74) which greatly affects the NO concentrations.

• For Nitric Oxide (NO2); the NO2 concentrations shows sensitivity towards

the following reaction; N+OH=>NO+H (R-62) CH4+CN<=>HCN+CH3 (R-

45) and NO2+H<=>NO+OH (R-84) at 1500 °C and N+OH=>NO+H (R-62),

NO2+H<=>NO+OH (R-84) and NO+NH<=>N2O+H (R-75) at 4000 K

during the combustion of natural gas in IC engine.

Similarly, in Figure 5.36 sensitivity of NH3 concentrations towards the most important

reactions are shown at temperature of 1500 K and 4000 K. This sensitivity bar-plot shows

that N2+O=>NO+N, N+OH=>NO+H and O2+N<=>NO+O

160

Figure 5.32 CO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-IV in IC engine at equivalence ratio =1.0 when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitivity Coefficient-0.03 -0.02 -0.01 0 0.01 0.02 0.03

CH4+CN<=>HCN+CH3

O2+N<=>NO+O

O2+CN<=>NCO+O

N2+CH<=>HCN+N

OH+CN<=>NCO+H

B

Normalized Logrithmic Sensitivity Coefficient-0.035-0.03-0.025-0.02-0.015-0.01-0.005 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035

CH4+N<=>NH+CH3

CH4+CN<=>HCN+CH3

O2+N<=>NO+O

O2+CN<=>NCO+O

N2+CH<=>HCN+N

HCN+OH<=>CN+H2O

OH+CN<=>NCO+H

H2O+CH<=>CH2O+HA

161

Figure 5.33 CO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-IV in IC engine at equivalence ratio =1.0 when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitivity Coefficient-0.3 -0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

CH4+N<=>NH+CH3

CH4+CN<=>HCN+CH3

O2+N<=>NO+O

O2+CN<=>NCO+O

N2+CH<=>HCN+N

NO+H=>N+OH

N+OH=>NO+H

NO+CH<=>HCN+O

N2+O=>NO+N

N2H2+M<=>NNH+H+M

HCN+OH<=>CN+H2O

HNCO+OH<=>NH2+CO2

CH3+N<=>H2CN+H

OH+CN<=>NCO+H

H2O+CH<=>CH2O+H

A

Normalized Logrithmic Sensitvity Coefficient-0.6 -0.4 -0.2 0 0.2 0.4 0.6

NO+H=>N+OH

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

O+NH<=>N+OH

OH+NH<=>HNO+H B

162

Figure 5.34 NO Sensitivity bar Plot for Natural Gas Combustion with Mechanism-IV in IC engine at equivalence ratio =1.0 when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitivity Coefficient-0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3

CH4+N<=>NH+CH3

CH4+CN<=>HCN+CH3

O2+N<=>NO+O

O2+CN<=>NCO+O

N2+CH<=>HCN+N

NO+H=>N+OH

N+OH=>NO+H

NO+CH<=>HCN+O

NO+N=>N2+O

N2+O=>NO+N

NO2+H<=>NO+OH

HCN+OH<=>CN+H2O

HNCO+OH<=>NH2+CO2

O+NH<=>N+OH

OH+NH<=>N+H2O

OH+CN<=>NCO+H

H2O+CH<=>CH2O+H A

Normalized Logrithmic Sensitivity Coefficient-0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

N2H2+M<=>NNH+H+M

N2H2+M<=>2NH+M

O+NH<=>N+OH

OH+NH<=>HNO+H B

163

Figure 5.35 NO2 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-IV in IC engine at equivalence ratio =1.0 when (A) T=1500 K and (B) T=4000 K

Normalized Logrithmic Sensitvity Coefficient-0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6

CH4+N<=>NH+CH3CH4+CN<=>HCN+CH3

O2+N<=>NO+OO2+CN<=>NCO+OCO2+N<=>NO+CON2+CH<=>HCN+N

NO+H=>N+OHN+OH=>NO+H

NO+CH<=>HCN+ONO+N=>N2+ON2+O=>NO+N

NO2+H<=>NO+OHNO2+M<=>NO+O+M

HCN+O<=>CN+OHHCN+OH<=>CN+H2O

HNCO+OH<=>NH2+CO2CH3+N<=>H2CN+H

O+NH<=>N+OHOH+NH<=>HNO+HOH+NH<=>N+H2OOH+CN<=>NCO+H

NH+M<=>N+H+MH2O+CH<=>CH2O+H

A

Normalized Logrithmic Sensitivity Coefficient-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

NO+NH<=>N2O+H

NO2+H<=>NO+OH

NO2+M<=>NO+O+M

N2H2+M<=>NNH+H+M

O+NH<=>N+OH

OH+NH<=>HNO+H

OH+CN<=>NCO+H

N+NCO<=>NO+CN

B

164

Figure 5.36 NH3 Sensitivity bar Plot for Natural Gas Combustion with Mechanism-IV in IC engine at equivalence ratio =1.0 when (A) T=1500 K and (B) T=4000 K

Normalized Logrithimic Sensitivity Coefficients-1.6 -1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4

CH4+N<=>NH+CH3

CH4+CN<=>HCN+CH3

O2+N<=>NO+O

O2+CN<=>NCO+O

N2+CH<=>HCN+N

NO+H=>N+OH

N+OH=>NO+H

NO+CH<=>HCN+O

NO+N=>N2+O

N2+O=>NO+N

HCN+OH<=>CN+H2O

O+NH<=>N+OH

OH+NH<=>HNO+H

OH+NH<=>N+H2O

OH+CN<=>NCO+H

H2O+CH<=>CH2O+H

A

Normalized Logrithmic Sensitivity Coefficient-0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8

NO+H=>N+OH

N+OH=>NO+H

NO+N=>N2+O

N2+O=>NO+N

N2H2+M<=>NNH+H+M

O+NH<=>N+OH

OH+NH<=>HNO+H

OH+NH<=>N+H2O

N+NCO<=>NO+CN

B

165

5.5 Summary:

The rate of production analysis (ROP) and sensitivity analysis (SA) of four

kinetic mechanisms was carried out for the formation of important pollutants

species. The major ROP analysis identified the reactions contributing the formation

of pollutant species of NO, NO2, NH3, CO and CO2 at two temperature extremes of

1500 K and 4000 K. This analysis also revealed that different types of reactions are

involved at both temperatures.

The total ROP versus crank rotational angle plots indicate that Mechanism-II

(high temperature) and Mechanism-III (low temperature) predict the occurrence of

earlier combustion process in combustion chamber while Mechanism-I &

Mechanism-IV predict the closer actual engine processes especially combustion

pattern. The sensitivity analysis of the detailed kinetic mechanism identified the

reactions of reaction rates influenced the output concentrations of pollutants

species.

Base upon the parametric analysis discussed in Chapter-4 and ROP and

sensitivity versus time plots of each species predict that Mechanism-IV (simplified

version of Mechanism-I) is representative reaction schemes of natural gas

combustion in IC engines predict the pollutants species.

166

CHAPTER-6

Uncertainty Analysis of Proposed Kinetic Mechanisms

In this chapter, uncertainty analysis of proposed

kinetic mechanisms is discussed. The purpose of

this analysis is to determine the uncertainties

originating due to kinetic parameters of rate of

reaction from each of the reaction of the

mechanism. This uncertainty analysis includes

the variance analysis and error analysis. In

uncertainty analysis, the accuracy of

approximate models, generated by the Chemkin

4.1.1 for pollutant species, is determined. The

percentage contribution to the uncertainty in the

output concentrations of pollutants also

determined.

167

6.1 Introduction:

There wide application of detailed kinetic reaction mechanisms in multiple fields of

application such as atmospheric chemistry, combustions systems, pyrolysis etc. These

proposed reaction models have been verified or tested against experimental measurements.

Usually, both experimental result and simulation based results do not coincides perfectly.

The level of agreements between the results can be estimated by measurements errors and

uncertainty existing in the simulation results.

A discussed in the Chapter-4 the errors among the simulation data and experimental data of

pollutants species exists in combustion chamber of IC engine. In Chapter-4, the uncertainty

originating from the input operating parameters has been discussed and in current study,

local uncertainty of kinetic parameters four proposed kinetic reaction mechanism has been

discussed.

The contribution of errors individual elementary reaction of a reaction mechanism

calculated by the variance analysis of estimated models for each species. In this analysis,

for each reaction, the percentage contribution of error in the predicted profile of each

pollutants species is calculated under the various simulation conditions.

The uncertainty factor due to Factor “A” of Arrhenius Rate Law is defined as;

⎟⎠⎞⎜

⎝⎛=⎟

⎠⎞⎜

⎝⎛= o

j

j

j

oj

k

k

k

kjf

max

min 1010 loglog (1)

where 0jk is the recommended values of the rate coefficient of reaction j.

minkj , maxkj are the lower and upper limits of rate coefficients. These minimum and

maximum values of rate parameters corresponding to 2σ deviation from the recommended

value on log scale, the uncertainty factor defined above can be converted to the variance of

logarithm of rate coefficient using the relation ( ) ( )( )22 2/10lnln jj fk =σ . In the lack of

168

detailed information and based on central limits thermo, normal distribution was assumed

for the parameter lnk. Also assuming that, the reaction rate coefficients are not correlated,

the variance of model output Yi is calculated by;

( ) ( ) ( )jkY

ik kYj

i

jln22

ln2 σσ ∂

∂= (2)

( ) ( )ij

kjik YY ∑= 22 σσ (3)

where, the subscript K means to an uncertainty originating form the kinetic parameters.

σ2(lnkj)

The percentage contribution of error due to each reaction involved in the formation and

consumption of pollutants is defined by the equation;

( )( ) 100% 2

2

×=i

ij

Y

YijS

σ

σ (4)

In this equation, ( )ij Y2

σ and ( )iY2

σ are defined further as;

)()( 22ikii YY σσ = (5)

and

( )ij

jij YY ∑= 22 )( σσ (6)

σk, is the variance coefficients due to Factor “A” which is the temperature coefficient of

respectively.

6.2 Uncertainty Analysis of Detailed Mechanisms by Chemkin 4.1.1:

Chemkin 4.1.1 has built in simulation routine for local uncertainty analysis of input

operating parameters (engine speed, equivalence ratio, initial inlet pressure, temperature of

gas mixture, etc), engine geometrical parameters (compression ratio, crank to connecting

rod ratio, starting crank rotation angle, etc) and kinetic parameters (temperature exponent,

169

temperature coefficient, activation energy, etc). The local uncertainty analysis has the great

advantage that the origin of the uncertainty can be traced to the various input parameters.

IC engine code of Chemkin 4.1.1 was used for simulation. The sequential

calculations with kinetic parameters (Factor A of Arrhenius Rate Law) for local sensitivity

coefficients were made by modifying this code. These local sensitivities were converted to

uncertainty using KINALC.

In present study, the contribution of reactions involved in the formation and

consumption of pollutant species (NO, NO2, NH3 and CO) to the concentrations in the

combustion chamber of IC engine with the specifications given in Table 4.1.the uncertainty

analysis of proposed reactions mechanisms was carried out for fuel lean conditions and fuel

rich conditions but the results shown in plots were obtained at stoichiometric condition

(when fuel-to-air ratio, φ=1.0) and when engine was operating at 3000 RPM, Tini=1500 K

and Pini=1.0 atm. The common reactions involved in the formation and consumption of the

pollutants species are given in Table 4.13. According to this Table, there are about 17, 52,

12 and 14 reactions involved the CO, NO, NO2, and NH3 respectively.

The uncertainty analysis by Chemkin solver involved the;

• Approximation of output models in which the algebraic equations are

developed for each out variables (Mole Fractions of pollutant species) to

approximate for given values of the input variables.

• Error Analysis, it gives the results of error analysis on the approximate

models. It includes a list of comparisons between the output values from the

actual model and those from the approximations. The most important

information is the relative sum-square-root error and the index of agreement.

A small relative sum-square-root error (i.e. << 1.0) and a high index of

agreement (i.e. close to 1.0) indicate high accuracy of the approximation. On

170

the other hand, either a large relative sum-square-root error or a low index of

agreement indicates poor accuracy of the approximation. The results are not

given for this study.

• Variance analysis indicates the effect of variation (or uncertainty) in input

variables on the variation (or uncertainty) in the model response of output

variables. A high percentage contribution from an input means that there is a

strong dependency of the output on the input. A low percentage contribution

means that the input has little effect on the output.

The results of variance analysis are important in uncertainty analysis of kinetic

mechanisms. The results of variance analysis of four proposed kinetic mechanism

(discussed in Chapter-3 and Chapter-4) with normal distribution (assumed for the

parameter lnk as discussed above) discussed in next section each reactions mechanisms

developed to simulate combustion of natural gas in IC engine.

6.3 Results and Discussion: In this section, the results of variance analysis of kinetic mechanisms is presented

and percentage contribution of each reactions involved in the output concentrations of

pollutant species is discussed.

The partial variances ( ( )ikj Y2σ ) of each individual reaction and their percentage to

overall variances illustrate the share of uncertainty of parameter “j” to the uncertainty of

output “i”. In this analysis, the reactions are identified which contribute the uncertainty in

output concentrations of pollutant species in each proposed reaction mechanisms.

Mechanism-I

The uncertainty analysis of comprehensive reaction Mechanism-I are given in Table

6.1 and shown in Figure 6.1 for error analysis and variance analysis. The output value of

171

Relative Sum-Square-Root Error (RSSRE) and Index of Agreement (IOA) indicate that

approximate concentration (given by algebraic equation) model acceptable level of

accuracy for CO, NO and NH3.

According to Figure 6.1, the main sources of uncertainty (above 10%) are the rate

parameters of reaction H+NCO=NH+CO (60.81%) and NO+C=CO+N (14.38%) for CO

concentrations in IC engine at equivalence ratio of =1.0. For specie NO, NO2, and NH3

Table 6.1 Error Analysis of Mechanism-I for Output Pollutants Species Concentrations

Pollutant Species Relative Sum-Square-Root Error Index of Agreement CO 7.5738E-05 0.50762 NO 2.10341E-05 0.62421 NO2 1.23743E-05 0.35233 NH3 4.65783E-04 0.57029

172

Percentage Contribution0 10 20 30 40 50 60 70

NO+C=CO+N

N+NCO=N2+CO

NCO+M=N+CO+M

H+NCO=NH+CO

O+NCO=NO+CO

NO+NCO=N2O+CO

14.4%

9.7%

60.8%

9.1% CO

Percentage Contribution0 2.5 5 7.5 10 12.5 15 17.5 20 22.5

O2+NCO=NO+CO2

O+HNO=OH+NO

NH2+HNO=NH3+NO

O2+NH=NO+OH

N+OH=>NO+H

N2+O=>NO+N

NO2+H=NO+OH

NO2+O=NO+O2

NO2+N=NO+NO

NO2+NH=HNO+NO

NO2+CN=NCO+NO

NO2+M=NO+O+M

OH+HNO=NO+H2O

OH+NCO=NO+HCO

OH+NCO=NO+CO+H

N+NCO=NO+CN

HNO+M=H+NO+M

2.6%

2.2%

10.4%

4.6%

3.7%

14.3%

12.3%

3.6%

2.3%

1.8%

13.4%

2.0%NO

173

Figure 6.1 Major reactions contributing to the uncertainty of Pollutant Species

CO, NO, NO2 and NH3 concentrations at Equivalence ratio =1.0, 3000 rpm, T=1500 K and P=1.0 atm for kinetic Mechanism-I

Following reaction is major contributor to uncertainty in output concentrations (above 10%) For Nitric Oxide (NO); only five reactions shows uncertainty contribution;

Percentage Contribution0 20 40 60 80

NH3+M=NH+H2+M

NH2+NH2=NH3+NH

NH2+NNH=N2+NH3

NH2+HNO=NH3+NO

65.3%

11.3%

20.1%

NH3

Percentage Contribution0 5 10 15 20 25 30 35 40

NO+N2O=N2+NO2

NO+N2H2=N2O+NH2

NO2+NO2=NO+NO+O2

NO2+NH=N2O+OH

NO2+NH2=N2O+H2O

NO2+CN=NCO+NO

NO2+M=NO+O+M

33.4%

2.8%

35.8%

12.3%

10.6%

NO2

174

1. O2+NH=NO+OH (10.45%),

2. N+OH=>NO+H (21.32%),

3. NO2+NH=HNO+NO (14.28%),

4. NO2+M=NO+O+M (12.31%)

5. N+NCO=NO+CN (13.4%)

For Nitrogen dioxide (NO2); four reactions are main sources (10%) of uncertainty

for NO2 formation given below

1. NO+N2O=N2+NO2 (23.35%)

2. NO2+NH=N2O+OH (12.34%)

3. NO2+NH2=N2O+H2O (35.76%)

4. NO2+CN=NCO+NO (17.56%)

For Ammonia (NH3); three reactions (above 10 %) are main contributor to

uncertainty to NH3 concentrations given below

1. NH2+NH2=NH3+NH (65.29%)

2. NH2+NNH=N2+NH3 (11.31%)

3. NH2+HNO=NH3+NO (20.06%)

Mechanism-II

The uncertainty analysis of kinetic Mechanism-II (a low temperature mechanism) is

shown in Figure 6.2 and error analysis of this detailed mechanism is given in Table 6.2.

The results plotted in Figure 6.2 for pollutants species CO, NO, NO2 and NH3 shows that

the major sources of uncertainty to the concentration of these species are the following

reactions (The reaction showing the uncertainty above 10% are given below.);

For Carbon monoxide (CO);

175

1. NCO+M=N+CO+M (28.61%)

2. CO2+N=NO+CO (14.38%)

3. HNCO+M=NH+CO+M (28.37)

For Nitric Oxide (NO); 1. O2+NCO=NO+CO2 (11.56 %)

2. NH2+HNO=NH3+NO (17.25%)

3. NO2+M=NO+O+M (21.32%)

4. HNO+M=H+NO+M (30.18%)

For Nitrogen Dioxide (NO2)

1. NO2+NH2=N2O+H2O (34.34%)

2. NO2+CN=NCO+NO (10.91%)

3. NO2+M=NO+O+M (30.26%)

For Ammonia (NH3) 1. NH3+M=NH+H2+M (43.34%)

2. NH2+NH2=NH3+NH (15.32%)

3. HNCO+NH2=NH3+NCO (31.29%)

4. NH2+HNO=NH3+NO (10.05%)

Table 6.2 Error Analysis of Mechanism-II for Output Pollutants Species Concentrations

Pollutant Species Relative Sum-Square-Root Error Index of Agreement CO 2.17038E-02 0.207862 NO 6.01205E-02 0.092322 NO2 8.31421E-03 0.357530 NH3 5.18142E-01 0.021892

176

Percentage Contribution0 3 6 9 12 15 18 21 24 27 30

NO+C=CO+N

N+NCO=N2+CO

NCO+M=N+CO+M

H+NCO=NH+CO

O+NCO=NO+CO

NO+NCO=N2O+CO

CO2+N=NO+CO

NO+HCCO=HOCN+CO

HNCO+M=NH+CO+M

9.3%

3.0%

4.5%

9.1%

14.4%

CO

Percentage Contribution0 5 10 15 20 25 30 35

O2+NCO=NO+CO2

O+HNO=OH+NO

NH2+HNO=NH3+NO

NO2+CN=NCO+NO

NO2+M=NO+O+M

OH+HNO=NO+H2O

OH+NCO=NO+HCO

OH+NCO=NO+CO+H

HNO+M=H+NO+M

11.6%

6.3%

17.2%

6.4%

21.3%

4.5%

30.2%

NO

177

Figure 6.2 Major reactions contributing to the uncertainty of Pollutant Species

CO, NO, NO2 and NH3 concentrations at Equivalence ratio =1.0, 3000 rpm, T=1500 K and P=1.0 atm for kinetic Mechanism-II

Percentage Contribution0 5 10 15 20 25 30 35

NO+N2O=N2+NO2

NO+N2H2=N2O+NH2

NO2+NO2=NO+NO+O2

NO2+NH=N2O+OH

NO2+NH2=N2O+H2O

NO2+CN=NCO+NO

NO2+M=NO+O+M

NO2+NH2=N2O+H2O

NO2+H=NO+OH

3.2%

2.8%

4.6%

3.4%

10.9%

30.3%

2.8%

7.6% NO2

Percentage Contribution0 10 20 30 40 50

NH3+M=NH+H2+M

NH2+NH2=NH3+NH

HNCO+NH2=NH3+NCO

NH2+HNO=NH3+NO

43.3%

15.3%

31.3%

10.0%NH3

178

The error analysis data given in Table 6.2 predict that the approximate models for the

concentrations estimated using mechanism-II in IC engine are accurate one and did not

coincide with the actual models as indicate the IOA data for each pollutant specie. This

shows that Mechanism-II is unable to predict actual pollutants concentrations.

Mechanism-III

Similarly, the uncertainty analysis mechanism-III are shown in Figure 6.3 and error

analysis results are given in Table 6.3. The calculated Index of Agreement (IOA) for each

of pollutant specie is very low which indicate that the estimated models for pollutant

species do not exhibit the closer agreement between the estimated response and the actual

model response of IC engine.

The percentage contribute each individual reactions involved in the pollutant

species is calculated using IC engine code of Chemkin 4.1.1 under given simulation

conditions. The reaction given below are those showing more that 10% share of

contribution to the uncertainty output concentrations formed in combustion chamber of IC

engine. According to this, only five reactions have more than 10% share of contribution to

uncertainty of predicted concentrations and similarly O2+NCO=NO+CO2,

N2O+C=CN+NO; NO2+NO2=NO+NO+O2, NO2+O=NO+O2, NO2+NH=N2O+OH;

OH+NH2=>O+NH3 and NH2+HNO=NH3+NO reactions share more than 10% of over all

uncertainty of output concentrations of NO, NO2 and NH3 respectively.

The error analysis results and other discrepancies discussed in Chapter-4 indicate low

temperature mechanism (Mechanism-III) do not predict the accurate results in IC engine.

Table 6.3 Error Analysis of Mechanism-III for Output Pollutants Species Concentrations

Pollutant Species Relative Sum-Square-Root Error Index of Agreement CO 6.7132E-04 0.2071867 NO 1.70642E-03 0.1267202 NO2 2.0813E-04 0.137053 NH3 7.1405E-04 0.072180

179

Percentage Contribution0 2 4 6 8 10 12 14 16

CO2+N=NO+CO

NO+C=CO+N

NO+CH=CO+NH

NO+HCCO=HOCN+CO

NO+NCO=N2O+CO

HCN+O=NH+CO

HNCO+H=NH2+CO

HNCO+O=HNO+CO

HNCO+M=NH+CO+M

H+NCO=NH+CO

O+CN=CO+N

O+NCO=NO+CO

OH+NCO=NO+CO+H

HCCO+N=HCN+CO

N+NCO=N2+CO

NCO+M=N+CO+M

NCO+M=N+CO+M

11.3%

3.8%

3.7%

2.5%

7.6%

1.6%

12.7%

2.7%

2.2%

2.3%

1.3%

13.4%

13.2%

4.5%CO

Percentage Contribution0 2 4 6 8 10 12 14 16 18

O2+NCO=NO+CO2

O+HNO=OH+NO

NH2+HNO=NH3+NO

N+OH=>NO+H

NO2+N=NO+NO

NO2+NH=HNO+NO

NO2+CN=NCO+NO

NO2+M=NO+O+M

N2O+C=CN+NO

N2O+O=NO+NO

N2O+N=N2+NO

N2H2+O=NH2+NO

H+HNO=H2+NO

O+NH=NO+H

O+NNH=NH+NO

O+HNO=OH+NO

O+NCO=NO+CO

OH+HNO=NO+H2O

OH+NCO=NO+HCO

OH+NCO=NO+CO+H

N+NCO=NO+CN

NH2+HNO=NH3+NO

16.4%

2.7%

6.3%

2.8%

5.5%

2.6%

2.9%

9.2%

11.3%

5.4%

6.5%

2.4%

3.6%

6.2%

3.1%

1.3%

5.6%

1.7%

NO

180

Figure 6.3 Major reactions contributing to the uncertainty of Pollutant Species

CO, NO, NO2 and NH3 concentrations at Equivalence ratio =1.0, 3000 rpm, T=1500 k and P=1.0 atm for kinetic Mechanism-III

Percentage Contribution0 3 6 9 12 15 18 21 24 27 30 33 36

NH3+H=NH2+H2

NH3+O=>NH2+OH

NH3+OH=NH2+H2O

NH3+HO2=NH2+H2O2

HNCO+NH2=NH3+NCO

NH3+M=NH+H2+M

NH2+NNH=N2+NH3

NH2+NH2=NH3+NH

NH3+NH2=N2H3+H2

NH3=NH2+H

H+N2H3=NH+NH3

OH+NH2=>O+NH3

NH2+HNO=NH3+NO

6.5%

2.8%

8.3%

2.5%

2.8%

6.7%

26.3%NH3

Percentage Contribution0 5 10 15 20 25 30 35 40 45 50 55

NO2+NO2=NO+NO+O2

NO2+H=NO+OH

NO2+O=NO+O2

NO2+N=NO+NO

NO2+NH=HNO+NO

NO2+NH=N2O+OH

NO2+NH2=N2O+H2O

NO2+M=NO+O+M

23.7%

12.7%

NO2

181

Main sources of uncertainty of CO predictions are;

1. CO2+N=NO+CO (11.34%)

2. NO+NCO=N2O+CO (15.06%)

3. HNCO+O=HNO+CO (12.67%)

4. HCCO+N=HCN+CO (13.44%)

5. NCO+M=N+CO+M (13.22%)

Main sources of uncertainty predicted NO concentrations are;

1. O2+NCO=NO+CO2 (16.4%)

2. N2O+C=CN+NO (11.32%)

Main sources of uncertainty predicted NO2 concentrations are;

1. NO2+NO2=NO+NO+O2 (23.7%)

2. NO2+O=NO+O2 (51.76%)

3. NO2+NH=N2O+OH (12.7%)

Main sources of uncertainty predicted NH3 concentrations are;

1. OH+NH2=>O+NH3 (26.3%)

2. NH2+HNO=NH3+NO (35.25%)

Mechanism-IV The results of uncertainty analysis of this mechanism are shown in Figure 6.4 and in

Table 6.5. According to the data of approximate models for pollutant species shows high

accuracy as very low values of Relative Sum-Square-Root Error (RSSRE) and higher

values (close to unity) of Index of Agreement (IOA) for each of pollutants under given

simulation conditions. Theses error analysis results indicate that the predicted profiles of

pollutant specie (for CO, NO, NO2 and NH3) give the accurate results as discussed in

Chapter-4.

182

The variance analysis of formation of pollutants species are shown in Figure 6.4. The

reaction NO+C=CO+N (81.8%) is the main source of uncertainty in predated concentration

of carbon monoxide (CO) under given simulation condition for IC engine. Similarly, the

main source of uncertainty in NO concentrations are reactions O2+NCO=NO+CO2 (44.4%)

and O+HNO=OH+NO (44.4%) and following reactions are major contributor to

uncertainty of nitrogen dioxide (NO2); (only reaction with above 10%)

1. NO+N2O=N2+NO2 (13.45%)

2. NO2+H=NO+OH (22.34%)

3. NO2+O=NO+O2 (15.76%)

4. NO2+N=N2O+O (12.56%)

5. NO2+NH=HNO+NO (12.67%)

Four reactions given below are the main source of uncertainty (above 10%)

1. H+N2H3=NH+NH3 (45.29%)

2. OH+NH2=>O+NH3 (12.76%)

3. NH2+NH2=NH3+NH (15.27%)

4. NH2+HNO=NH3+NO (17.72%)

Table 6.4 Error Analysis of Mechanism-IV for Output Pollutants Species

Concentrations Pollutant Species Relative Sum-Square-Root Error Index of Agreement

CO 5.17038E-08 0.8071862 NO 7.70665E-07 0.923724 NO2 1.80863E-07 0.95751 NH3 1.7466E-06 0.7997189

183

Percentage Contribution0 20 40 60 80 100

NO+C=CO+N

N+NCO=N2+CO

NCO+M=N+CO+M

81.8%

9.1%

9.1%

CO

Percentage Contribution0 5 10 15 20 25

O2+NCO=NO+CO2

O+HNO=OH+NO

NH2+HNO=NH3+NO

44.4%

44.4%

11.1%

NO

184

Figure 6.4 Major reactions contributing to the uncertainty of Pollutant Species

CO, NO, NO2 and NH3 concentrations at Equivalence ratio =1.0, 3000 rpm, T=1500 kand P=1.0 atm for kinetic Mechanism-IV

Percentage Contribution0 2 4 6 8 10 12 14 16 18 20 22 24

NO+N2O=N2+NO2

NO+N2H2=N2O+NH2

NO2+NO2=NO+NO+O2

NO2+H=NO+OH

NO2+O=NO+O2

NO2+N=NO+NO

NO2+N=N2O+O

NO2+NH=HNO+NO

NO2+NH=N2O+OH

NO2+NH2=N2O+H2O

NO2+CN=NCO+NO

NO2+M=NO+O+M

13.4%

3.7%

3.7%

15.7%

7.5%

12.5%

12.6%

2.7%

2.2%

2.6%

NO2

Percentage Contribution0 5 10 15 20 25 30 35 40 45 50

NH3+M=NH+H2+M

H+N2H3=NH+NH3

OH+NH2=>O+NH3

NH2+NH2=NH3+NH

NH2+NNH=N2+NH3

NH2+HNO=NH3+NO

6.5%

45.3%

12.8%

15.3%

17.7% NH3

185

6.4 Summary: The variance analysis and error analysis of four kinetic reaction mechanisms

were carried out. The approximate models showing the contribution of the variation

input variables were determined for pollutants (CO, NO, NO2 & NH3) species

formed in IC engine. The variance analysis identified the reactions which

contribute the uncertainty in the output of the approximate models from the

individual reactions involving the formation or consumption of pollutants. The

error analysis produced very useful results. The error analysis of approximate

models from Mechanism-IV predicts that this mechanism produces accurate results.

186

CHAPTER-7

Investigation of Kinetic Mechanisms of Methane Oxidation

In this chapter, the combustion of methane was simulated using

four kinetic models of methane in CHEMKIN 4.1.1 for 0-D closed

internal combustion (IC) engine reactor. Two detailed

(GRIMECH3.0 & UBC MECH2.0) and two reduced (One step &

Four steps) models were examined for various IC engine designs.

The detailed models (GRIMECH3.0, & UBC MECH2.0) and 4-

step models successfully predicted the combustion while global

model unable to predict any combustion reaction. This study

illustrated that the detailed model showed good concordances in

the prediction of chamber pressure, temperature and major

combustion species profiles. The detailed models were also

exhibited the capabilities to predict the pollutants formation in an

IC engine while reduced schemes showed failure in the prediction

of pollutants emissions. Although, there are discrepancies among

the profiles of four considered model, the detailed models

(GRIMECH3.0 & UBC MECH2.0) produced the acceptable

agreement in the species prediction and formation of pollutants.

187

7.1 Introduction:

Oxidation models of methane combustion, reported in the literature [Kaufman,

1982; Bowman et al, 2001; Frenklach et al, 1992; Peters, 1993 & 1985; Magel et al, 1996;

West brook, 1985; Glarborg et al, 1986; Miller, 1989; Konnov, 2000; Hughes et al, 2001;

Gregory et al; West Brook, 1981; Duterque et al, 1981; Hautmann et al, 1985; ] Jones et al,

1988; Tianfeng et al, 2005; Lavoie et al, 1970], were used to study methane

combustion/burning in furnaces, burners, bunsen flame burner, etc. Simulation of the CH4

combustion in an internal combustion engine is very important to the design of engine and

the control of air pollutants derived form the exhaust. One of the key objectives is to

establish a kinetic model, in which the pressure and temperature profile in the engine, and

the important reactants and products can be simulated.

In current study, consequences of the selected (detailed & reduced) models for the profiles

of temperature, pressure and major species produced are discussed. An appropriate model

which predicts combustion species like NOx, CO, CO2, and H2O, etc in engine combustion

chamber is identified. The simple criteria of comparing simulation results (profiles) of

detailed and reduced models as followed in study was described by Hemant, et al, 1996.

7.2 Implantation of Detailed and Reduced Kinetic Mechanism of Methane Oxidation in IC engine: In this study, we set our simulation starting crank angle to -142 degrees in the

software input. Other simulation parameters we used in the software simulation were cycles

end time as 0.043 sec or for 257 degrees crank angle to 115 degrees after TDC. The gas

mixture pressure and temperature at IVC are 107911 Pa (or 1.065 atm) and 550 K,

respectively. Following four mechanisms were investigated for methane combustion in

internal combustion engines as given in Table 7.1.

188

Table 7.1 Tested Mechanism of Methane Combustion

Where, A, β, Ta (Ta= Ea/T) are the parameters for Arrhenius Law defined below;

RTEa

eATk −= β Two of these models are the detailed such as GRIMECH 3.0 & UBC MECH2.0 and other

two are reduced such as Duterque (Global One Step) & Jones and Lindstedt (Four Steps).

Two types of data files are required to input for execution of CHEMKIN module; (i)

Mechanism data files and (ii) thermodynamics data files.

Table 7.2 Important Species Considered in UBC MECH 2.0 and GRI MECH 3.0 Kinetic Models

Detailed Kinetic Model

No of Species

No of Reactions

Important Reacting Species/Intermediates (Radicals)

UBC

MECH2.0 54 277

H2 H O O2 OH H2O HO2 H2O2 C CH CH2 CH2(S) CH3 CH4 CO2 CO CH2O CH2OH CH3O CH3OH C2H C2H2 C2H3 C2H4 C2H5 C2H6 HCCO CH2CO HCCOH N2 AR CH3O2 CH3O2H C2H5O C2H5O2 C2H5O2H CH3CO CH3CHO C2H4O C2H3O C3H8 nC3H7 iC3H7 nC3H7O2 iC3H7O2 nC3H7O2H iC3H7O2H nC3H7O iC3H7O C3H6 C3H5 C3H4 C2H4O2H

GRI3.0 53 325

O O2 OH H2O HO2 H2O2 C CH CH2 CH2(S) CH3 CH4 CO CO2 HCO CH2O CH2OH CH3O CH3OH C2H C2H2 C2H3 C2H4 C2H5 C2H6 HCCO CH2CO HCCOH N NH NH2 NH3 NNH NO NO2 N2O HNO CN HCN H2CN HCNN HCNO HOCN HNCO NCO N2 AR C3H7 C3H8 CH2CHO

Some important species and reaction (pressure dependent) of both detailed models are

given in Table 7.2 to 7.4.

Sr. No

Kinetic Model Type

Reactions Arrhenius Parameters A β Ta(K)

1 Global One-Step Reaction

CH4+2O = CO2+2H2O 1.50E+13 0.0

20000.0

2 Four Step Reaction Models of Jones and Lindstedt

(i) CH4+1/2O2 = CO+2H2 4.40E+14 0.0 24000.0

(ii) CH4+H2O = CO+3H2 3.00E+1 0.0 24000.0 (iii) H2+1/2O2 = H2O 2.50E+1 -1.0 32000.0 (iv) CO+H2O = CO2+H2 2.75E+12

0.0 16000.0

3 GRIMECH 3.0 (53 species & 325 reactions)(available on Internet).

4 UBC MECH2.0 Kinetic mechanism available on Internet at http://kbspc.mech.ubc.ca/kinetics.html.

189

Table 7.3 Some Important Reactions of GRI MECH 3.0 Mechanism (Pressure & Temperature dependent Reactions are listed)

Sr. No Reactions

(k = A Tβ exp(-E/RT)) A (mole-cm-sec-K) Β E

(cal/mole) 1 O+H2<=>H+OH 3.87E+04 2.7 6260 2 O+H2O2<=>OH+HO2 9.63E+06 2 4000 3 O+CH4<=>OH+CH3 1.02E+09 1.5 8600 4 O+CH3OH<=>OH+CH2OH 3.88E+05 2.5 3100 5 O+CH3OH<=>OH+CH3O 1.30E+05 2.5 5000 6 O+C2H2<=>H+HCCO 1.35E+07 2 1900 7 O+C2H2<=>OH+C2H 4.60E+19 -1.4 28950 8 O+C2H2<=>CO+CH2 6.94E+06 2 1900 9 O+C2H4<=>CH3+HCO 1.25E+07 1.8 220

10 O+C2H6<=>OH+C2H5 8.98E+07 1.9 5690 11 H+O2<=>O+OH 2.65E+16 -0.7 17041 12 H+H2O2<=>HO2+H2 1.21E+07 2 5200 13 H+CH3(+M)<=>CH4(+M) 1.39E+16 -0.5 536 14 H+CH4<=>CH3+H2 6.60E+08 1.6 10840 15 H+HCO(+M)<=>CH2O(+M) 1.09E+12 0.5 -260 16 H+CH2O(+M)<=>CH2OH(+M) 5.40E+11 0.5 3600 17 H+CH2O(+M)<=>CH3O(+M) 5.40E+11 0.5 2600 18 H+CH2O<=>HCO+H2 5.74E+07 1.9 2742 19 H+CH2OH(+M)<=>CH3OH(+M) 1.06E+12 0.5 86 20 H+CH2OH<=>OH+CH3 1.65E+11 0.7 -284 21 H+CH2OH<=>CH2(S)+H2O 3.28E+13 -0.1 610 22 H+CH3O(+M)<=>CH3OH(+M) 2.43E+12 0.5 50 23 H+CH3O<=>H+CH2OH 4.15E+07 1.6 1924 24 H+CH3O<=>OH+CH3 1.50E+12 0.5 -110 25 H+CH3O<=>CH2(S)+H2O 2.62E+14 -0.2 1070 26 H+CH3OH<=>CH2OH+H2 1.70E+07 2.1 4870 27 H+CH3OH<=>CH3O+H2 4.20E+06 2.1 4870 28 H+C2H3(+M)<=>C2H4(+M) 6.08E+12 0.3 280 29 H+C2H4(+M)<=>C2H5(+M) 5.40E+11 0.5 1820 30 H+C2H4<=>C2H3+H2 1.32E+06 2.5 12240 31 H+C2H5(+M)<=>C2H6(+M) 5.21E+17 -1 1580 32 H+C2H6<=>C2H5+H2 1.15E+08 1.9 7530 33 H2+CO(+M)<=>CH2O(+M) 4.30E+07 1.5 79600 34 OH+H2<=>H+H2O 2.16E+08 1.5 3430 35 2OH<=>O+H2O 3.57E+04 2.4 -2110 36 OH+CH3(+M)<=>CH3OH(+M) 2.79E+18 -1.4 1330 37 OH+CH3<=>CH2+H2O 5.60E+07 1.6 5420 38 OH+CH3<=>CH2(S)+H2O 6.44E+17 -1.3 1417 39 OH+CH4<=>CH3+H2O 1.00E+08 1.6 3120 40 OH+CO<=>H+CO2 4.76E+07 1.2 70 41 CH3+CH2O<=>HCO+CH4 3.32E+03 2.8 5860

190

42 CH3+CH3OH<=>CH2OH+CH4 3.00E+07 1.5 9940 43 CH3+CH3OH<=>CH3O+CH4 1.00E+07 1.5 9940 44 CH3+C2H4<=>C2H3+CH4 2.27E+05 2 9200 45 CH3+C2H6<=>C2H5+CH4 6.14E+06 1.7 10450 46 HCO+H2O<=>H+CO+H2O 1.50E+18 -1 17000 47 HCO+M<=>H+CO+M 1.87E+17 -1 17000 48 CH3O+O2<=>HO2+CH2O 4.28E-13 7.6 -3530 49 C2H+H2<=>H+C2H2 5.68E+10 0.9 1993 50 C2H3+O2<=>HCO+CH2O 4.58E+16 -1.4 1015 51 C2H4(+M)<=>H2+C2H2(+M) 8.00E+12 0.4 86770 52 N+O2<=>NO+O 9.00E+09 1 6500 53 NH+O2<=>NO+OH 1.28E+06 1.5 100 54 NH2+OH<=>NH+H2O 9.00E+07 1.5 -460 55 NNH+M<=>N2+H+M 1.30E+14 -0.1 4980 56 H+NO+M<=>HNO+M 4.48E+19 -1.3 740 57 HNO+H<=>H2+NO 9.00E+11 0.7 660 58 HNO+OH<=>NO+H2O 1.30E+07 1.9 -950 59 CN+H2<=>HCN+H 2.95E+05 2.5 2240 60 NCO+NO<=>N2O+CO 1.90E+17 -1.5 740 61 NCO+NO<=>N2+CO2 3.80E+18 -2 800 62 HCN+M<=>H+CN+M 1.04E+29 -3.3 126600 63 HCN+O<=>NCO+H 2.03E+04 2.6 4980 64 HCN+O<=>NH+CO 5.07E+03 2.6 4980 65 HCN+O<=>CN+OH 3.91E+09 1.6 26600 66 HCN+OH<=>HOCN+H 1.10E+06 2 13370 67 HCN+OH<=>HNCO+H 4.40E+03 2.3 6400 68 HCN+OH<=>NH2+CO 1.60E+02 2.6 9000 69 CH+N2<=>HCN+N 3.12E+09 0.9 20130 70 CH2+NO<=>H+HNCO 3.10E+17 -1.4 1270 71 CH2+NO<=>OH+HCN 2.90E+14 -0.7 760 72 CH2+NO<=>H+HCNO 3.80E+13 -0.4 580 73 CH2(S)+NO<=>H+HNCO 3.10E+17 -1.4 1270 74 CH2(S)+NO<=>OH+HCN 2.90E+14 -0.7 760 75 CH2(S)+NO<=>H+HCNO 3.80E+13 -0.4 580 76 HNCO+O<=>NH+CO2 9.80E+07 1.4 8500 77 HNCO+O<=>HNO+CO 1.50E+08 1.6 44000 78 HNCO+O<=>NCO+OH 2.20E+06 2.1 11400 79 HNCO+H<=>NH2+CO 2.25E+07 1.7 3800 80 HNCO+H<=>H2+NCO 1.05E+05 2.5 13300 81 HNCO+OH<=>NCO+H2O 3.30E+07 1.5 3600 82 HNCO+OH<=>NH2+CO2 3.30E+06 1.5 3600 83 HCNO+H<=>H+HNCO 2.10E+15 -0.7 2850 84 HCNO+H<=>OH+HCN 2.70E+11 0.2 2120 85 HCNO+H<=>NH2+CO 1.70E+14 -0.8 2890 86 HOCN+H<=>H+HNCO 2.00E+07 2 2000

191

Table 7.4. Some Important Reactions of UBC MECH2.0 Mechanism (only Pressure & Temperature dependent Reactions are listed)

Sr. No Reactions (k = A Tβ exp(-E/RT))

A (mole-cm-sec-K) Β E (cal/mole) 1 O+H2<=>H+OH 5.00E+04 2.7 62902 O+H2O2<=>OH+HO2 9.63E+06 2 40003 O+CH4<=>OH+CH3 1.02E+09 1.5 86004 O+CH3OH<=>OH+CH2OH 3.88E+05 2.5 31005 O+CH3OH<=>OH+CH3O 1.30E+05 2.5 50006 O+C2H2<=>H+HCCO 1.02E+07 2 19007 O+C2H2<=>OH+C2H 4.60E+19 -1.4 289508 O+C2H2<=>CO+CH2 1.02E+07 2 19009 O+C2H4<=>CH3+HCO 1.92E+07 1.8 220

10 O+C2H6<=>OH+C2H5 8.98E+07 1.9 569011 H+CH3(+M)<=>CH4(+M) 1.27E+16 -0.6 38312 H+CH4<=>CH3+H2 6.60E+08 1.6 1084013 H+HCO(+M)<=>CH2O(+M) 1.09E+12 0.5 -26014 H+CH2O(+M)<=>CH2OH(+M) 5.40E+11 0.5 360015 H+CH2O(+M)<=>CH3O(+M) 5.40E+11 0.5 260016 H+CH2O<=>HCO+H2 2.30E+10 1.1 327517 H+CH3OH<=>CH2OH+H2 1.70E+07 2.1 487018 H+CH3OH<=>CH3O+H2 4.20E+06 2.1 487019 H+C2H3(+M)<=>C2H4(+M) 6.08E+12 0.3 28020 H+C2H4(+M)<=>C2H5(+M) 1.08E+12 0.5 182021 H+C2H4<=>C2H3+H2 1.32E+06 2.5 1224022 H+C2H5(+M)<=>C2H6(+M) 5.21E+17 -1 158023 H+C2H6<=>C2H5+H2 1.15E+08 1.9 753024 OH+H2<=>H+H2O 2.16E+08 1.5 343025 OH+CH2<=>CH+H2O 1.13E+07 2 300026 OH+CH3<=>CH2+H2O 5.60E+07 1.6 542027 OH+CH4<=>CH3+H2O 1.00E+08 1.6 312028 OH+CO<=>H+CO2 4.76E+07 1.2 7029 OH+CH2O<=>HCO+H2O 3.43E+09 1.2 -44730 OH+CH3OH<=>CH2OH+H2O 1.44E+06 2 -84031 OH+CH3OH<=>CH3O+H2O 6.30E+06 2 150032 OH+C2H2<=>H+CH2CO 2.18E-04 4.5 -100033 OH+C2H2<=>H+HCCOH 5.04E+05 2.3 1350034 OH+C2H2<=>C2H+H2O 3.37E+07 2 1400035 OH+C2H2<=>CH3+CO 4.83E-04 4 -200036 OH+C2H4<=>C2H3+H2O 3.60E+06 2 250037 OH+C2H6<=>C2H5+H2O 3.54E+06 2.1 87038 CH+H2<=>H+CH2 1.11E+08 1.8 167039 CH2+H2<=>H+CH3 5.00E+05 2 723040 CH2+CH4<=>2CH3 2.46E+06 2 827041 CH2+CO(+M)<=>CH2CO(+M) 8.10E+11 0.5 451042 2CH3(+M)<=>C2H6(+M) 2.12E+16 -1 62043 2CH3<=>H+C2H5 4.99E+12 0.1 10600

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44 CH3+CH2O<=>HCO+CH4 3.32E+03 2.8 586045 CH3+CH3OH<=>CH2OH+CH4 3.00E+07 1.5 994046 CH3+CH3OH<=>CH3O+CH4 1.00E+07 1.5 994047 CH3+C2H4<=>C2H3+CH4 2.27E+05 2 920048 CH3+C2H6<=>C2H5+CH4 6.14E+06 1.7 1045049 HCO+H2O<=>H+CO+H2O 2.24E+18 -1 1700050 HCO+M<=>H+CO+M 1.87E+17 -1 1700051 CH3O+O2<=>HO2+CH2O 4.28E-13 7.6 -353052 C2H+H2<=>H+C2H2 4.07E+05 2.4 20053 C2H4(+M)<=>H2+C2H2(+M) 8.00E+12 0.4 8877054 CH3+O2<=>CH3O2 8.52E+58 -15 1701855 C2H5+O2<=>C2H5O2 1.10E+47 -10.6 1483056 C2H5+O2<=>C2H5O+O 1.10E+13 -0.2 2792657 C2H5+O2<=>CH3CHO+OH 1.60E+14 -1.2 1039258 C2H3+O2<=>C2H3O+O 6.61E+06 1.9 97959 C2H3+O2<=>C2H2+HO2 8.40E+05 1.9 224660 OH+C3H8<=>C3H7+H2O 7.08E+06 1.9 158.9

Table 7.2 shows some common species and intermediates (or radicals) present in the

reacting mixture for both detailed kinetic models and these models have about 44 common

reactions. In Table 7.3 & 7.4, only the pressure dependent reactions are listed as apparent

from value of Arrhenius parameter “β”.

We have simulated the combustion of methane with four models (Table 7.1) with different

engine specifications (An example of engine specifications is given in Table 7.5).

Table 7.5 Example of Test Engines Specifications used in Simulation of Methane Combustion

Parameters Values Compression Ratio 10.0

Cylinder clearance volume (cm3) 1530

Engine Speed (rpm) 1000 Connecting rod to crank radius ratio 2.97729 Cylinder bore diameter (mm) 102

Displacement (cm) - More details about the engine specifications, used in this simulation, exist in the literature.

The other simulation inputs to the CHEMKIN software are given in Table7.6 and adopted

from Heywood.

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Table 7.6 General Input Parameters; Parameters Values

Heat transfer correlation coefficients Coefficient a 0.035 Coefficient b 0.71 Coefficient c 0.0

Woschni Correlation coefficients C11 2.28 C12 0.308 C2 3.24

Wall Temperature (K) 400 The composition of the initial gas mixture is a combination of natural gas, air, and Exhaust

Gas Recirculation (EGR) gas and is given in Table 7.7.

Table 7.7 Composition (Mole Fraction) of Initial Gas Mixture

Species Mole Fraction CH4 0.8709 C2H6 0.105 C3H8 0.0027 CO2 0.0205 N2 0.072

7.3 Results & Discussion:

The combustion of methane in engine cylinder was simulated with four kinetic

model schemes and we used various input parameters.

In this section, we focus more on the consequences of the used four kinetic reaction

schemes (models) methane oxidation for the predicted pressure, temperature, profiles and

major combustion species including gaseous pollutants. The predicting capabilities of

theses models under similar simulation conditions were also discussed and an appropriate

reaction scheme (detailed & reduced) was identified simply based on the simulation results.

Figure 7.1 &7.2 shows the pressure and temperature profiles respectively of four

models for the adiabatic and stoichiometric conditions (Initial Inlet Temperature, Tini=447

K, Initial Inlet Pressure, Pini=1.07 bar and Φ=1.0). As shown in the figures, reduced model

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(Duterque, Jones and Lindstedt) predict the earlier combustion that with the detailed

models. The reason of this deviation in delay is that the species and temperature reaches

their end values very sharply. Each pressure profile clearly show that the peak cylinder

pressure occur close to TC (Top-Center). At TC, this pressure built up is closely related to

the rate of burning of the premixed fuel mixture. There is early built up of pressure with

reduced model (Duterque, Jones and Lindstedt) than detailed reaction schemes (UBC

MECH2.0 & GRIMECH 3.0). The detailed models predict the maximum cylinder pressure

and temperature of approximately of 40 atm and 2000 K respectively. In case of reduced

models, the predicted pressure and temperature significantly deviate.

Figure 7.1 Predicted Pressure Profiles for Equivalence Ratio of φ =1.0 (Tini=447 K, Pini=1.07 bar)

These deviations prediction of pressure and temperature occur due to reaction paths for of

detailed and reduced models.

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Figure 7.2 Predicted Temperature Profiles for Equivalence Ratio of φ =1.0 (Tini=447 K, Pini=1.07 bar)

Figure 7.3 demonstrate the main combustion species profiles of fuel (CH4, CO2), and water

vapours (H2O) at stoichiometric conditions. Obviously, 4-step model predicts the early

consumption of fuel than the both detailed models. If we look at the profiles of the

produced species (CO2 and H2O), 4-step model dictate that these species are formed at the

earlier stage very rapidly and later on, these consumed at the intermediates steps (which

indicate the pyrolysis of fuel) and then produced. These intermediates then further oxidized

to CO which then oxidized to CO2.

196

197

Figure 7.3 Major Species Profiles for Equivalence Ratio of φ =1.0 (Tini=447 K, Pini=1.07 bar).

It is clear from Figure 7.3 that, both detailed models (GRIMECH 3.0 & UBC MECH2.0)

and 4-steps model predict CO emissions and one step global model fails in this regard

because there is no CO pathway in the model. In each graph of CO and NOx (as NO2),

reduced model show the early formation than detailed models.

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Figure 7.4 NOx and CO Emissions for Equivalence Ratio of φ =1.0 (Tini=447 K, Pini=1.07 bar). [Note; NOx is used as collective term for NO2 & N2O]

Each profile of N2O graph illustrate that N2O is formed immediately during the combustion

and then its fraction decreased as shown in Figure 7.4. The reason for this production of

N2O production is oxidation N2 with O2 and the further conversion into NO2 and NO. There

is rapid formation of NO than NO2. On the whole, reduced models (only the 4-steps

mechanism) predict the higher fractions than the detailed reaction schemes.

In the light of above simulation results, detailed models are more appropriate in prediction

of combustion species and pollutants formation in IC engine chamber. The results (Figure

5.1-5.4) of present study predict that GRIMECH3.0 model could be utilized in practical

design on an IC engine for low emissions.

7.4 Summary:

In this chapter, combustion of methane (major constituent of natural gas or CNG,

about 90% by wt) was simulated using four kinetic models of methane in CHEMKIN 4.1.1

for 0-D closed internal combustion (IC) engine reactor. Two detailed (GRIMECH3.0 &

UBC MECH2.0) and two reduced (One step & 4-step) models were examined for various

IC engine designs. The detailed models (GRIMECH3.0, & UBC MECH2.0) and 4-step

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models successfully predicted the combustion while global model unable to predict any

combustion reaction. This study illustrated that the detailed model showed good

concordances in the prediction of chamber pressure, temperature and major combustion

species profiles. The detailed models also exhibited the capabilities to predict the pollutants

formation in an IC engine while reduced schemes showed failure in the prediction of

pollutants emissions. Although, there are discrepancies among the profiles of four

considered model, the detailed models (GRIMECH3.0 & UBC MECH2.0) produced the

acceptable agreement in the species prediction and formation of pollutants.

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CHAPTER-8

Experimental Investigation of CNG

Combustion in IC Engine and

Pollutants Emissions

This chapter describes the design of the experimental

setup developed to study the effect of various operating

parameters on the CNG combustion in an automobile

engine (a type an IC engine). The basic purpose of the

development of this setup is to acquire the experimental

data for the validation of the simulation data obtained

using Chemkin 4.1.1 for four proposed kinetic

mechanisms. In this experimental study, the in-cylinder

profiles of temperature, pressure and pollutant species

(CO, NO, NO2 & NH3) were recorded under various

operating conditions of an automobile engine. The

simulation data for each of the proposed mechanism is

compared with experimental data for and an appropriate

mechanism of CNG combustion is selected which showed

the closer agreement with the experimental results.

Mechanism-IV consisting of 208 elementary reactions

exhibits the closer agreement with the experimental data

under the given engine operating conditions

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8.1 Introduction:

Combustion is key process of converting chemical energy to heat which is

ultimately converted to mechanical (Motion) energy to derive in IC engine. Due to this

combustion, pressure and temperature suddenly rise within the engine chamber which

provides the driving force to push the piston back to produce the motion in the automobile.

In a conventional spark-ignition engine the fuel and air are mixed together in the

intake system, inducted through the intake valve into the cylinder, where mixing with

residual gas takes place, and then compressed. Under normal operating conditions,

combustion is initiated towards the end of the compression stroke at the spark plug by an

electric discharge. Following inflammation, a turbulent flame develops, propagates through

this essentially premixed fuel, air, burned gas mixture until it reaches the combustion

chamber walls, and then extinguishes. The spark discharge is at - 30°. The flame first

becomes visible in the photos at about -24°. The flame, approximately circular in outline in

this view through the piston, then propagates outward from the spark plug location. The

blue light from the flame is emitted most strongly from the front. The irregular shape of the

turbulent flame front is apparent. At TC the flame diameter is about two-thirds of the

cylinder bore. The flame reaches the cylinder wall farthest from the spark plug about 15°

ATC, but combustion continues around parts of the chamber periphery for another 10°. At

about 10° ATC, additional radiation-initially white, turning to pinky-orange-centered at the

spark plug location is evident. This afterglow comes from the gases behind the flame which

burned earlier in the combustion process, as these are compressed to the highest

temperatures attained within the cylinder (at about 15° ATC) while the rest of the charge

burns.

Nitric oxide (NO) forms throughout the high-temperature burned gases behind the flame

through chemical reactions involving nitrogen and oxygen atoms and molecules, which do

202

not attain chemical equilibrium. The higher the burned gas temperature, the higher the rate

of formation of NO. As the burned gases cool during the expansion stroke the reactions

involving NO freeze, and leave NO concentrations far in excess of levels corresponding to

equilibrium at exhaust conditions. Carbon monoxide also forms during the combustion

process. With rich fuel-air mixtures, there is insufficient oxygen to burn fully all the carbon

in the fuel to CO2; also, in the high-temperature products, even with lean mixtures,

dissociation ensures there are significant CO levels. Later, in the expansion stroke, the CO

oxidation process also freezes as the burned gas temperature falls.

8.2 Objectives:

The major objectives of this experimental study were;

• To characterize the CNG combustion in tested engine cylinder by the

pressure and temperature profiles and emission profiles of CO and oxides of

nitrogen (NOx).

• Comparison of engine performance by the experimental data profiles of

pressure, temperature and emissions with those of the simulation based data

profiles for proposed four mechanisms constructed in the Chapter-3.

• Selection of appropriate kinetic mechanisms showing closer results with the

experimental data.

8.3 Description of Experimental Setup:

Commercially available fuel system serves as a basis for the new fuel system

design. A schematic diagram of the bi-fuel engine rig set up is shown in Figure 8.1. The

Figure 8.2 to 8.3 shows the actual experimental setup which provides the frame work for

the entire study. The engine tested in this study is a spark plug IC engine and widely used

in 3-wheelers automobile rickshaw in Pakistan (also called as CNG rickshaw). The engine

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is bi-fuel operated and a CNG conversion kit is used to form this bi-fuel engine. The

combustion chamber body of the tested engine is made of steel, inside of which there is a

cylinder sleeve. The piston completed a stroke in average time of averages 0.067 s. This is

equivalent to a crankshaft type engine running at 90 revolutions per minute (RPM). The

detail tested specifications of tested engine is given in Table 8.1.

To measure the in-cylinder pressure, a special spark plug with a built-in pressure

sensor was used. It is a diode laser based electric spark plug (Figure 8.4). A general

purpose and fast transient pressure transducer (Kistler, Model 603B1) was used to measure

cylinder pressure. This sensor was combined with a charge amplifier (Kistler, Model 5010)

is used for dynamic cylinder pressure measurements, that is, the pressure relative to the

atmosphere or gauge pressure. A high precision angle displacement sensor with a one

degree resolution was added to the crankshaft. The data acquisition for the pressure sensor

was triggered by the crank angle sensor such that a pressure measurement was taken every

crank angle degree.

The fast time response of the transducer (1 p~s) made it possible to record the

pressure change during the air intake stroke and to determine the final inducted air quantity.

The combustion chamber wall temperature is maintained at 40°C by means of cooling

water circulated around the combustion chamber of the engine and monitored by using a

thermocouple installed on the cylinder wall.

The exhaust system was also outfitted with several thermocouples. On the exhaust

side, a Horiba was used to analyze the emissions and determine the composition of the

gases. Excluding the in-cylinder pressure sensors, the data was acquired at 100 Hz through

a 12 bit data acquisition system.

During the experiment, data collection is performed with a Personal Computer

equipped with an AJD board (Data Translation, Model DT2837). Eight channels of data

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collected are the time histories of the trigger signal (used as time reference) and cylinder

pressure. Data for all individual tests are normalized based on the initial time reference

signal.

The electric spark is generated by an inductive ignition system and is triggered by an

electronic ignition module (GM, Model 466 9H02). The spark plug used has an electrode

gap of 0.85 mm and spark plug (Champion Spark Plug Co.) is used, as shown in Figure 5.

During the firing cycle a square wave pulse is generated when a moving metal pin passes

by a fixed optical switch. This square pulse, serving as the system trigger signal (time equal

to zero), is sent directly to a pulse generator (Hewlett Packard, Model 8081A) and then to a

delay generator (Berkeley Nucleonics Corp., Model 7050) to initiate firing of the laser or

electric spark discharge and to trigger the streak camera. A photodiode detector

(Hamamatsu, Model C1083) is used to detect the spark emission light from the laser as

well as the spark plug electrodes.

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Figure 8.1 Schematic Diagram of Experimental Setup.

M

1 2 3

Air Intake

200 CC Engine

5

4

9

6 7 8

RPM Sensor/Tachometer

Cylinder Pressure Transducer

Temperature Measurements

Engine RPM data

Gas Flow rate

Air Flow Rate

Online Gas Analyzer

A/D Board

Data Logger

11

10

P

Petrol Line CNG Line Data Line Gas Wiring

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Figure 8.2 View of Experimental Setup showing Gas Analyzers

Figure 8.3 Side View of Experimental Setup showing different Components of Experimental Setup

Gas Cylinder

Horiba CO & NOx Online Analyzers

Petrol Tank

Gas Conversion Kit

200 CC IC Engine

Exhaust Cooling System Air Flow rate

meter

Display and Control Panel

Gas Fuel Flow Rate Adjustment Point

RPM Sensor

Gas Flow Rate sensor

Fuel Selector Switch

Exhaust Sampling point-I

Exhaust Sampling point-II

Moisture Free Air Line

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Figure 8.4 Diode-laser-based Spark Plug used in this study.

Figure 8.5 Installation of Spark-plug Ignition System in Combustion Chamber of Tested IC Engine showing [1] inflamed spherical volume, [2] piston ring, [3] piston cavity, and [4] fused silica optical window.

Table 8.1 Experimental Setup Components

No Component No Component

1 Petrol Tank 7 CNG Solenoid Valve

2 Petrol Solenoid 8 GAS (CNG, Methane, Fuel B) Storage Tank

3 Petrol Flow Meter 9 Spark Timing Advancer

4 CNG Mixer 10 Spark Plug

5 Carburetor 11 Fuel Selector switch

6 CNG Pressure Regulator

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Table 8.1a Specification Tested Engine used in 4-Stoke Automobile Rickshaws.

Parameter Typical Value

Engine Capacity 200 CC

Compression Ratio 10.51

Bore, mm 33.5

Stroke, mm 35.5

Cylinder volume (cm3) 63

Displaced Volume (cm3) 56.52

Clearance Volume (cm3) 6.48

Cylinder Diameters (cm) 14.67

Crank to Connecting rod ratio 1.632

Carburetor 2-barreldown-draft

Specification of CNG Carburetion System

Regulator LANDI RENZO TN1-B-SIC

Mixer Remote extractor

Spark advancer STAP 51

8.4 Results and Discussion: All the testing was conducted on the setup discussed above to study to characterize

the combustion in the tested engine. Although this engine is bi-fuel fired (Petrol & CNG)

but in current study, we conducted the experiments for three gaseous fuels where Fuel-A is

commercially available compressed natural gas (CNG), Fuel-B is gaseous fuel containing

only C1-C3 hydrocarbons and Fuel-C is the pure methane. Later two type of fuels were

prepared particularly for this study. The basic objective was to explore the variation

occurring due the methane contents in the fuel. The detail composition of each type of fuel

is given in Table 8.1b. The measured data exploited significant variation in in-cylinder

pressure, temperature, species profile formed within the combustion chamber and in the

exhaust. The combustion in the tested engine was characterized by the cylinder

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temperature, pressure and emission profiles for each selected fuel. At the end, the measured

cylinder temperature, pressure and pollutants emission profiles (for CO, NO, NO2) were

compared with the modeled (kinetic mechanisms) results obtained by the combustion

simulations using Chemkin 4.1.1 simulation software. In this study, the combustion for

each fuel. Based upon the comparative results, an appropriate kinetic reaction model

(discussed in Chapter-3 & Chapter 4) was predicted.

Table. 8.1b Fuel Composition (Mole Fraction) Contents Fuel-A Fuel-B* Fuel-C*

Hydrocarbons Methane (CH4) 0.8871 0.7901 1.000 Ethane (C2H6) 0.0103 0.1285 - Propane (C3H8) 0.0028 0.077 - Butane (C4H10) 0.0018 0.0027 -

Non-Hydrocarbons

Carbon dioxide (CO2)

0.026 0.0017 -

Nitrogen (N2) 0.072 - - * BOC Pakistan Fuel-A: It is commercially distributed CNG fuel used as automobile fuel. The data

was collected from Sui Northern Gas Pipe Line Limited (SNGPL). This

contains C1-C4 hydrocarbons and CO2 & N2.

Fuel-B: This contains compressed lower hydrocarbons (C1-C4) and this mixture was

especially prepared for this particular research study.

Fuel-C This contains only compressed methane (100 %)

8.4.1 Investigation of Pressure and Temperature in Engine Cylinder:

Chamber pressure and temperature profiles are two important parameters to

understand the complete engine cycle of tested CNG fired IC engine.

Combustion starts before the end of the compression stroke, continues through the early

part of expansion stroke. When spark discharge (nearly at -30°), the flame become visible,

then stabilize and subsequent propagate through the fuel mixture. Following the spark

discharge, there is period during which very small amount of heat releases as the flame is in

developing phase. As the flame continues to grow and propagate across the combustion

210

chamber, the pressure steadily rises (above the value there was no combustion initiated).

The pressure rises to maximum after Top Center (TC) of the chamber but before the

cylinder charge is fully burned and then decreases as the piton move back (increasing the

cylinder volume) during expansion stroke. A quartz sensor used to measure chamber

pressure. This sensor detects the pressure with a quartz crystal, of one end is exposed

through diaphragm to the chamber pressure. When the chamber pressure is increased, it

generates electric charge output (proportional to pressure). The signal is then transmitted

through a low noise coaxial cable to charge amplifier (Kistler Type, Model-5010) which

amplify the signal in proportion to voltage. The recorded pressure data was plotted versus

crank angle (the time of complete cycle duration which 4-stroke was converted to crank

angle position with simulation model Chemkin 4.1.1).

During the pressure measurements, substantial variation was observed in consecutive

operating cycles (One engine cycle consist of 4-strokes and completed in 0.0077 sec and

swap 720 ° crank angle). This variation in measurements is plotted versus crank angle

position (or time measurements) and is illustrated in Figure 8.6 for six successive cycles at

3000 rpm under stoichiometric (φ=1.0) conditions. Each plot shows similar pattern of

variations of chamber pressure for each cycle and major variations occur in peak pressures

developing during the combustion process occurring from -20° to 0° crank angle. It is clear

from each plot that the curves are not smooth throughout the cycle. This indicates some

abnormalities in the combustion which make the process more complex. Some

unpredictable reactions (having fast rate of reactions and release high energies) may

responsible for these abnormalities. The pressure profile in Figure 8.7 is the average of

pressure variation which is looking smooth which shows that the stable engine operation.

The maximum peak pressure, 38.85 atm, was observed for fourth cycle (Cycle-A) which

indicate the faster burning of fuel mixture. It is very hard to predict the actual factors

211

causing these variation which indicate the complexities of the combustion but from each

figure it is clear that this variation develop during combustion process which is mainly

affected by;

• Variations in mixture motion within chamber at the time of spark cycle-by-cycle

• Variation in amounts of air and CNG fired the chamber

• Variation in mixing of fresh mixture and residual gases within the cylinder of last

cycle.

The average measured cylinder pressure from 0.61 atm to 32.62 atm for six (06)

consecutive engine cycles as shown in Figure 8.7.

Experiments were carried out to study the effect of fuel to air equivalence ratio on the

engine performance (in terms of temperature, pressure and emission profiles). Pressure and

temperature data of the engine cylinder were plotted versus crank angle positions. Cylinder

pressure profiles for various equivalence ratios (set by controlling fuel and air

212

Figure 8.6 Cylinder Pressure Measurements for Six Successive Cycles in CNG fired IC Engine operating at 3000 rpm, φ=1.0, Pinilet=0.67 atm.

Crank Rotation Angle-150 -100 -50 0 50 100 150 200

B

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e, a

tm

-150 -100 -50 0 50 100 150 2000

5

10

15

20

25

30

35

A

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e,at

m

-150 -100 -50 0 50 100 150 2000

5

10

15

20

25

30

35

40

C

Crank Rotation Angle-150 -100 -50 0 50 100 150 200

D

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e, a

tm

-150 -100 -50 0 50 100 150 2000

5

10

15

20

25

30

35

40

E

Crank Rotation Angle-150 -100 -50 0 50 100 150 200

F

213

Figure 8.7 Variation in Cylinder Pressure ((Average)) Measured for Six Successive Cycles in CNG fired IC Engine operating at 3000 rpm, φ=1.0, Pinlet =0.67 atm.

flow rates) ranging from fuel leaner (φ<1.0) to fuel rich ((φ<1.0) and stoichiometric

conditions (φ=1.0) of engine operating at 3000 rpm (with 10-20 rpm deviation), Pinilet=0.67

atm are shown in Figure 8.8.

Theses cycle measurements characterized the engine operation by determining the;

• Operating cylinder pressure limits (0.51-39.85 atm).

• Fastest and slowest burning cycle. Studies reveal that the fastest burning cycle is

most likely to knock. Thus the fastest cycle determine the fuel octane number for

smooth engine operation while the slowest cycle retard relative to optimum timing

and shows the most incomplete fuel burning. Now we can conclude that for the

optimum smooth engine operation, we have compromise the spark timing and

average fuel/air equivalence ratios.

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e, a

tm

-150 -100 -50 0 50 100 150 2000

5

10

15

20

25

30

35

214

• Determine the Engine Crank Position Angle (2.48° ATC) at which peak pressure is

reached during combustion.

For the fuel leaner condition (φ ≈0.6), maximum cylinder reached to about 18 atm and

there was significant rise could be seen in the plots of fuel rich condition (pressure rises up

to 40 atm maximum) for equivalence ration of φ=1.13 and 1.3. Unexpectedly, there was

lower maximum cylinder pressure (≈38 atm) was observed as shown in the plot for (φ

≈1.4).

The high cylinder pressure indicates the degree of completion of the combustion. In other

words, high pressure indicates that maximum release of the energy from the fuel contents

during combustion which predict that reactions go in favorable directions and lower

pressure depict the in-complete combustion which means that chemical reactions did not

released the maximum their energy which is available for useful purpose. The variation of

energy contents (in tem of sensible enthalpy & mixture enthalpy) of the reaction mixture in

the combustion chamber is simulated under various engine operating conditions for engine

cycle using Chemkin 4.1.1 (which solves the energy equation) can be observed

Figure 8.9 illustrates the behavior of combustion pressure in the engine cylinder for various

fuels containing methane as the major contents. The major objective of this experimental

study was observing the pattern of variation of different engine combustion processes.

215

Figure 8.8 Measured Cylinder Pressure at Various Equivalence Ratios of CNG Fired IC Engine operating at 3000 rpm, Pinilet=0.67 atm

Crank Rotation AngleC

ylin

der P

ress

ure,

atm

-80 -60 -40 -20 0 20 40 600

5

10

15

20

25

30

φ=1.0

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e, a

tm

-80 -60 -40 -20 0 20 40 600

2.5

5

7.5

10

12.5

15

17.5

20

ϕ=0.6

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e, a

tm

-80 -60 -40 -20 0 20 40 605

10

15

20

25

30

35

40

ϕ=1.1

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e, a

tm

-80 -60 -40 -20 0 20 40 605

10

15

20

25

30

35

40

ϕ=1.3

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e, a

tm

-80 -60 -40 -20 0 20 40 605

10

15

20

25

30

35

40

ϕ=1.4

216

Significant variations were observed in the collected data sets for pressure, temperature,

emission profiles

In this figure, Plot-A shows the cylinder pressure profiles when commercially

available CNG fuel (Table 1) was used as burning fuel. The maximum peak pressure was

about 39 atm at the end of the combustion process. Major deviation was observed for Fuel-

C (with pure methane contents).The profile indicate that there is little early start of

combustion process with pure methane fuel and maximum peak pressure of 26 atm in the

combustion chamber was recorded which is lower than peak combustion pressure we

recorded with Fuel-A and Fuel-B. This indicates that fuels with composition for Fuel-B

and Fuel-C cannot be used in the engines tested in this study.

217

Figure 8.9 Measured Cylinder Pressure for Various Fuels of IC engine Operating at 3000 rpm and φ=1.0

The pressure profiles of simulation data are compared with the experimental data obtained

for CNG fires tested engine operating at 3000 rpm under stoichiometric conditions. The

simulation conditions (set for ICE module of Chemkin 4.1.1) were kept similar to the

average experimental condition as given in Table 8.2.

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e, a

tm

-150 -100 -50 0 50 100 150 2000

5

10

15

20

25

30

35

40

Fuel-A

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e,at

m

-150 -100 -50 0 50 100 150 2000

5

10

15

20

25

30

35

Fuel-B

Crank Rotation Angle

Cyl

inde

r Pre

ssur

e, a

tm

-150 -100 -50 0 50 100 150 2000

5

10

15

20

25

30

Fuel-C

218

It is clear from Figure 8.10 that the curves for proposed kinetic Mechanism-I &

Mechanism-IV shows similar behavior throughout the cycle but the profile of Mechanism-

IV are in much closer agreement with the experimental data . On the basis of pressure

profiles (both simulation data & experimental data) for Mechanism-IV, we can conclude

that Mechanism-IV might be the representative of CNG combustion in IC engine under test

shown in Figure 8.1.

Figure 8.11 shows the variation of average cylinder temperature measured (using sensor in

the compact spark plug shown in Figure 8.4) for six successive engine cycles (each cycle

consist of 4-strokes). The average peaks cylinder reaches up to 3900 K when engine was

operating at 3000 rpm, φ=1.0, Pinilet=0.67 atm. Initial temperature rises (up to 1600 K) due

to the compress=ion stroke from -100° to -20° of crank angle position and after this there is

substantial increase in the temperature which is due to start of combustion process

(occurring between -20° & 2°). When expansion stroke starts, then fall of temperature was

observed and it continues with higher gradient for exhaust stroke.

Table 8.2. Input Variables for Simulating CNG Combustion in IC Engine

Variable Set Value

Compression ratio 10.51

Engine Speed (rpm) 3000

Initial Inlet pressure (atm) 0.67

Initial Inlet Temperature (C) 1000

Equivalence Ratio (φ) 1.0

219

Figure 8.10 Pressure Profiles for Four Proposed Kinetic Models (simulation with IC modules of Chemkin 4.1.1 and Experimental Cylinder Pressure data.

 

220

Figure 8.11 Average Cylinder Temperature of Six (06) Successive Operating Cycles of Engine operating at 300 rpm, φ=1.0, Pinilet=0.67 atm

The effect of fuel/air equivalence ratio on the cylinder temperature has been investigated in

the tested engine operating at 3000 rpm, Pinilet=0.67 atm for variable inlet equivalence ratio.

The graphs in Figure 8.12 shows that we have smooth pattern of variation in cylinder

temperature for fuel rich conditions for equivalence ratios of φ =1.1, 1.3 and 1.4. The

maximum peak temperature (about 4100 K) was observed when engine was gain

equivalence ratio of 1.3.

Crank rotation angle

Cyl

inde

r Tem

pera

ture

_(K

)

-150 -100 -50 0 50 100 150 200 2501200

1500

1800

2100

2400

2700

3000

3300

3600

3900

4200

221

.

Figure 8.12 Measured Cylinder Temperatures at Various Equivalence Ratios of CNG Fired IC Engine operating at 3000 rpm, Pinilet=0.67 atm

Crank Rotation AngleC

ylin

der T

empe

ratu

re, K

-80 -60 -40 -20 0 20 40 601000

1500

2000

2500

3000

3500

4000

4500

ϕ=1.0

Crank Rotation Angle

Cyl

inde

r Tem

pera

ture

,K

-80 -60 -40 -20 0 20 40 60500

1000

1500

2000

2500

3000

3500

4000

ϕ=0.6

Crank Rotation Angle

Cyl

inde

r Tem

pera

ture

,K

-80 -60 -40 -20 0 20 40 601000

1500

2000

2500

3000

3500

4000

4500

ϕ=1.1

Crank Rotation Angle

Cyl

inde

r Tem

pera

ture

,K

-80 -60 -40 -20 0 20 40 601000

1500

2000

2500

3000

3500

4000

4500

ϕ=1.3

Crank Rotation Angle

Cyl

inde

r Tem

pera

ture

,K

-80 -60 -40 -20 0 20 40 601500

2000

2500

3000

3500

4000

4500

ϕ=1.4

222

The peak temperatures and pressure observed in the combustion cylinder are given in Table

8.2a along with Mean values in the data for various equivalence ratios.

Table 8.2a Peak Cylinder Temperature and Pressure at Various Equivalence Ratios

Figure 8.12 shows the results of measured cylinder temperature for various fuels with

different compositions (as given in Table 8.1) in the tested engine operating at 3000 rpm

and fuel/air equivalence ratio of 1.0. There was significant variation in the each plot of

Figure 8.13. Plot-A shows the chamber temperature profiles when commercially available

CNG fuel with composition in Table 8.1 was used as fuel. The maximum peak temperature

was about 3900 K at the end of the combustion process. Major deviation was observed for

Fuel-C (with pure methane contents).The profile indicate that there is little early start of

combustion process with pure methane fuel and maximum peak temperature 3100 K in the

combustion chamber was recorded which is lower than peak combustion temperatures we

recorded with Fuel-A and Fuel-B. This indicates that fuels with composition for Fuel-B

and Fuel-C cannot be used in the engines tested in this study.

Equivalence Ratio (φ)

Temperature, (K) Pressure, (atm) Peak Mean St.Dev Peak Mean St.Dev

0.6 3976.07 3587.14 676.14 31.06 8.27 8.75 1.0 3994.09 3613.25 597.88 28.37 7.55 7.97

1.13 4053.30 3753.77 656.50 30.30 8.06 8.52 1.3 4168.4 3808.46 686.05 33.76 8.45 8.94 1.4 4100.56 3783.11 711.84 32.87 8.68 9.27

223

Figure 8.13 Measured Cylinder Temperature for Various Fuels of IC engine

Operating at 3000 rpm and φ=1.0

8.4.1.1 Cylinder Pressure and Exhaust Port Temperature:

Figure 8.14 shows the comparison of variation of average in-cylinder pressure and

exhaust port temperature measured simultaneously during exhaust stroke. These

Crank rotation angle

Cyl

inde

r Tem

pera

ture

,K

-150 -100 -50 0 50 100 150 200 2501200

1500

1800

2100

2400

2700

3000

3300

3600

3900

4200

Fuel-A

Crank rotation angle

Cyl

inde

r Tem

pera

ture

,K

-150 -100 -50 0 50 100 150 200 250900

1200

1500

1800

2100

2400

2700

3000

3300

3600

Fuel-B

Crank rotation angle

Cyl

inde

r Tem

pera

ture

,K

-150 -100 -50 0 50 100 150 200 250750

1000

1250

1500

1750

2000

2250

2500

2750

3000

3250

Fuel-C

224

experiments were conducted when engine was operating with out load at low speed (1000

rpm) at equivalence ratio of 1.3. According to this figure, the gas temperature is remained

nearly constant (nearly 430 K) before the exhaust valve is open and cylinder pressure falls

substantially to near 1.1 atm as the exhaust valve opened. The cylinder pressure remained

to its minimum during the exhaust valve remained opened and a lowest value was observed

nearly 0.6 atm as exhaust valve is closed. The gas temperature shows the temperature of

cooler gas mixture which stationed at the exit port from the previous exhaust stroke. As the

exit valve is opened, the hotter gas mixture left the combustion chamber and mixes with

cooler gas already present there and due these hotter gases, temperature at the exit port

suddenly rises up to 1050 K and then this temperature falls rapidly and continues to fall

during the exhaust stroke.

Figure 8.14 Exhaust Gas Measured Temperature at Exhaust Port Exit and Measured Cylinder Pressure, atm of CNG Fired IC Engine Operating at 3000 rpm, 0.67 atm, φ=1. 3

Crank Rotation Angle

Exha

ust P

ort T

emep

ratu

re,K

Cyl

inde

r Pre

ssur

e,at

m

120 150 180 210 240 270 300 330 360 390 420400 0

450 3

500 6

550 9

600 12

650 15

700 18

750 21

800 24

850 27

900 30

950 33

1000 36

1050 39

1100 42

TemperaturePressure

225

This fall in the temperature is due the heat transfer to the cylinder walls and exhaust valve

is closed. The port exit temperature was remained minimum where the transition from blow

down flow to the displacement occurs and the gas becomes momentarily to rest and loses

major portion of its heat contents to the exhaust port walls.

The temperature in the exit port affects the CO and NOx levels. The variation of NOx and

CO concentrations are shown in the Figure 8.22 and Figure 8.29 respectively.

8.4.2 Investigation of Pollutants Formation due to Combustion of CNG:

With the steady increase in combustion of hydrocarbon fuels, the products of

combustion are distinctly identified as a severe source of environmental damage. The major

combustion products are carbon dioxide and water. These products were, until recently,

considered harmless. Now, even the carbon dioxide is becoming a significant source in the

atmospheric balance, and concerns of a global greenhouse effect are being raised.

We investigated the two important members of criteria gaseous pollutants (CO &

NOx) emitted from the combustion of CNG fired IC engine used as test Engine (of 200

CC) shown in Figure 8.1.

The concentrations of oxides of nitrogen (NOx as sum of NO & NO2) and carbon monoxide

(CO) in engine exhaust were measured using online emission analyzer (Testo Model 350

XL) at various equivalence ratios. In cylinder measurements were (A new fast response NO

detector, based on the chemiluminescence (CLD) method has been used to measure

continuous, real-time levels of NO in the cylinder, and simultaneously in the exhaust port

of a virtually unmodified production SI engine. It is to remember that most of the

chemiluminescence based analyzers measure total oxide of the nitrogen emissions i.e.

NO+NO2.

The NOx concentrations data (as calculated as mole fraction of sum of NO & NO2

data) is plotted versus crank angle position as shown in Figure 8.15 for three fuels. The

226

data was collected when engine was operated at 3000 rev/min under stoichiometric

conditions (when φ=1.0). According to this figure, fluctuations in the NOx levels in the

combustion chamber were observed for Fuel-A after combustion process during expansion

and exhaust phases. While Fuel-B and Fuel-C shows smooth pattern of variation curves.

Early combustion was supported by the engine when fired by the Fuel-B and Fuel-C which

are containing only hydrocarbon contents. The Fuel-A profile shows that maximum NOx

concentrations were produced when engine was fired by the Fuel-A. These higher

concentrations might be due the fact that Fuel-A contains the nitrogen contents which

contribute the NOx chemistry in addition to the nitrogen from the air. The increase or

decrease of the concentrations of NOx after combustion indicates occurring of the reactions

during the expansion of the burned gas mixture but reactions consuming NOx molecules are

seems to dominant the producer reactions. During the exhaust phase, the constant levels

indicate the freezing of the NOx chemistry at the low temperature. We can conclude that

higher NOx levels were observed at higher temperatures in the combustion chamber.

227

Figure 8.15 Measured NOx Concentrations (In-Cylinder) for Three Fuel (3000

rev/min, φ=1.0 and Pinlet =0.67 atm) Most of the variation in the concentrations of these pollutants is shown in Figure 16 and

concentrations of NO and NO2 are shown Figure 8.17. The curves (in Figure 8.15 & Figure

8.16) illustrate that lower emissions were observed under lean mixture conditions (φ <1.0).

The shapes of these curves show the complexities emission controls. When engine

operation becomes stable (usually when fuel flow increased and combustible mixture

become fuel-rich), high concentrations of CO were observed while NOx levels were

lowered. During the measurements, it was also observed that when engine was operated

Crank rotation angle

Mea

sure

d N

Ox

Con

cent

ratio

ns, M

ole

Frac

tions

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

0.055

0.06

0.065

0.07

0.075

0.08

0.085

0.09

Fuel-A

Crank rotation angle

Mea

sure

d N

Ox

Con

cent

ratio

ns, M

ole

Frac

tions

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

Fuel-B

Crank roation angle

Mea

sure

d N

Ox

Con

cent

ratio

ns, M

ole

Frac

tions

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.003

0.006

0.009

0.012

0.015

0.018

0.021

0.024

0.027

0.03

Fuel-C

228

under load condition, leaner mixture produced lower CO emissions and moderate levels of

NOx emissions.

Figure 8.16 Variation of CO and NOx concentration in Exhaust of CNG fired IC

Engine (200 CC) at Various Equivalence Ratio (Fuel/Ratio)

Figure 8.16 and Figure 8.17 also indicate that highest concentration of NOx were near the

stoichiometric conditions and then become lower while CO level shows increasing trend.

There are two major sources of nitrogen to in fuel mixture (fuel nitrogen and air nitrogen)

in pre-mixed combustion of CNG in IC engine. Studies revealed that the fuel nitrogen is

source of NO via different mechanisms. During combustion, lower molecular weight

nitrogen-containing compounds such as ammonia (NH3), hydrogen cyanide (HCN) and

cyanide (CN). Simulation of CNG combustion in IC engine (Chemkin 4.1.1) predicts the

existence and formation of these precursor compounds on NO formation. Rate of

Production (ROP) analysis of each of mechanism was carried out to know which type of

reaction contribute the NOx formation at typical 3000 K under stoichiomteric conditions

11/2/2009

Equ Plot.grf

Fuel/Air Equivalence Ratio

CO

and

NO

x M

easu

red

Con

cent

ratio

ns (n

ot to

sca

le)

0 0.2 0.4 0.6 0.8 1 1.2 1.4

CONOx

229

(φ=1.0) at moderate speed of 3000 rpm. The ROP analysis shows that how much a

particular reaction contributes in production or consumption of a specie/product.

Figure 8.17 Variation in Concentrations of NO and NO2 in Engine Exhaust as

function of Equivalence Ratio

NO+NO2 PLot.grf

Fuel/Air Equivalence Ratio

NO

2 Em

issi

on C

once

ntra

tions

(ppm

)

NO

Em

issi

on C

once

ntra

tions

(ppm

)

0 0.2 0.4 0.6 0.8 1 1.2 1.40 0

2 40

4 80

6 120

8 160

10 200

12 240

NO2NO

230

Figure 8.18 shows the comparison of results of experimental data of in-cylinder NOx data

of IC engine fired with Fuel-A operating at 3000 rev/min and equivalence ratio of ≈ 1.0 and

simulation data of NOx (as mole fraction) obtained for four kinetic mechanisms using IC

engine module of Chemkin 4.1.1. The simulation conditions were set as given in Table 8.2.

Figure 8.18 Comparison of NOx Profiles (with Modeled data and Experimental data).

Table 8.3 shows the important plausible reactions involved in NOx formation due to CNG

combustion in IC engine and normalized rate of production coefficients. The positive (+ve)

value of Normalized ROP coefficient indicate the production or forward rate is dominate

while negative (-ve) value means the consumption or backward rate of reaction is

dominate.

Crank rotation angle

Mea

sure

d In

-Cyl

inde

r NO

x Le

vels

, Mol

e Fr

actio

ns

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

Mechanim-IMechanim-IIMechanim-IIIMechanim-IVExperimental Data

231

Table 8.3 Reactions Involved in Formation and Consumption of NOx (NO & NO2) in Proposed Four Kinetic Mechanisms with Calculated Normalized Rate of Production Coefficients

Mechanism Reaction Normalized Rate

of Production Coefficient

Mechanism-I

NO Reaction R-790. NO+H=>N+OH R-811. NO+M<=>N+O+M R-932. HNO+M<=>H+NO+M NO2 Reaction R-799. NO+HO2<=>NO2+OH R-814. NO2+O<=>NO+O2 R-818. NO2+NH<=>N2O+OH R-819. NO2+NH2<=>N2O+H2O R-821. NO2+M<=>NO+O+M

(-0.078) (1.000) (0.916)

(0.082) (0.014) (-0.038) (-0.617) (0.904)

Mechanism-II

NO-Reaction R-648. NO+H=>N+OH R-649. N+OH=>NO+H R-660. NO+N=>N2+O R-661. N2+O=>NO+N R-746. O+NH<=>NO+H R-789. HNO+M<=>H+NO+M NO2 Reactions R-657. NO+HO2<=>NO2+OH R-671. NO2+H<=>NO+OH R-672. NO2+O<=>NO+O2 R-679. NO2+M<=>NO+O+M

(-0.642) (0.870) (-0.349) (0.334) (0.024) (0.033)

(-0.064) (-0.460) (-0.475) (1.000)

Mechanism-III

NO Reactions R-704. O2+N<=>NO+O R-719. NO+H=>N+OH R-720. N+OH=>NO+H R-731. NO+N=>N2+O R-732. N2+O=>NO+N R-743. NO2+O<=>NO+O2 R-818. O+NH<=>NO+H

NO2 Reactions R-728. NO+HO2<=>NO2+OH R-742. NO2+H<=>NO+OH R-743. NO2+O<=>NO+O2 R-750. NO2+M<=>NO+O+M

(0.022) (-0.267) (0.626) (-0.210) (0.410) (0.014) (0.012)

(-0.086) (0.548) (-0.913) (0.452)

Mechanism-IV

Reaction NO R-61. NO+H=>N+OH R-62. N+OH=>NO+H R-73. NO+N=>N2+O R-74. N2+O=>NO+N R-82. NO+M<=>N+O+M R-84. NO2+H<=>NO+OH Reaction NO2 R-84. NO2+H<=>NO+OH R-92. NO2+M<=>NO+O+M

(-0.742) (0.063) (-0.239) (0.028) (0.905) (-0.015)

(0.789) (1.000)

The performance engine was tested with three different composition of CNG fuel. These

fuels varies in constituents but all the fuels have methane (CH4) as major component

232

Figure 8.19 shows the variation of NOx (NO2+NO) concentrations in the exhaust port

versus fuel/air equivalence ratios. The initial concentrations were lower and there was rapid

increase in NOx concentrations was measured. This increase in concentrations was because

the fresh mixture of hot gases just left the combustion chamber mixes with already

stationed cooler gas mixture from the previous exhaust stroke. The maximum NOx levels

were observed when Fuel-A was burned in the engine.

Figure 8.19 Variation of NOx Concentrations (Exhaust) for Different Fuels when Engine was operating at 3000 rpm

In Figure 8.20, the measured concentrations (by rapid gas sampling valve near the spark

plug) of in-cylinder gas mixture were plotted versus crank angle positions. There was the

deviation in the profiles of the NOx in-cylinder concentrations when engine was operated

with selected different fuels with given composition in Table 8.1. The maximum

concentrations were observed for commercial available CNG.

Fuel/Air Equivalence Ratio

NO

x C

once

ntra

tions

in E

xhau

st, p

pm

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.410

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

Fuel-AFuel-BFuel-C

233

Figure 8.20 Variation of NOx Concentrations (In-Cylinder) for Different Fuels

Figure 8.21 Variation of Ratio of In-Cylinder and Exhaust Concentrations of Oxides of Nitrogen (NOx) for Three Fuels.

Figure 8.21 shows the variation of NOx concentrations measured in exhaust and in-cylinder

measurements. A Box-Whisker plot of ratio of In-cylinder NOx concentrations and exhaust

Fuel/Air Equivalence Ratio

In-C

ylin

der N

Ox

Con

cent

ratio

ns, p

pm

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.40

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000

3200

3400

Fuel-AFuel-BFuel-C

Rat

io o

f In-

Cyl

inde

r and

Exh

aust

Con

cent

ratio

ns o

f NO

x

Fuel-A Fuel-B Fuel-C6

8

10

12

14

16

18

20

22

24

MaximumMinimum75%25%MedianOutliersExtremes

234

concentrations shows this variation for fuels used in the engine. According to this plot,

Fuel-B and Fuel-C show the maximum variation in the calculated ratios.

In Table 8.3, it is clear that while NO2 is converted to NO via reaction;

NO2+M<=>NO+O+M where M is the third body molecular specie or radical (which may

be OH).

Figure 8.17 shows the emission data NO and NO2 from the tested engine data measured at

various equivalence ratios. These figures indicate that the NOx formation is greatly affected

by Fuel/Air Equivalence Ratios. During the experiments, it was observed that as

equivalence ratio is increased, the oxygen concentrations were lowered and in parallel

burned gas temperature decreased. When mixture was leaned, increasing oxygen

concentrations offset the lowered gas temperature and NO emissions get peak

concentrations nearly at φ ≈0.97 while highest concentrations reached at φ ≈0.85.

When we analyze cylinder temperature, pressure, and NOx profiles for each of measuring

cycle (engine cycle) then the detailed predictions of NOx concentrations in the exhaust can

be well understood. The NOx concentrations show different character both under fuel lean

and fuel rich conditions. Based upon both simulations results (discussed in Chapter-3) and

experimental data, it can be concludes that;

• NO concentration become stable little early in the expansion process and a

little conversion of NO may occur in lean fuel mixture conditions.

• In fuel rich mixture, the sharp decrease in NO concentrations occurs from

peak values when cylinder pressure is maximum.

The NOx concentrations in the engine exhaust varied at different engine speeds. For this

study engine was operated at different speeds without load from 2000 rpm to maximum of

7000 rpm. At constant engine speed (say 2000 rpm), the NOx concentration in the exhaust

were monitored at various equivalence ratios (φ=0.2 to 1.4).

235

Figure 8.22 Measured NOx in Engine Exhaust at various Engine Speeds for Fuel-A

At low equivalence ratios (φ< 0.38), it was very difficult to keep the stable engine

operation especially at low speed. We observed the unpredictable behavior during each

experiment. The maximum NOx levels at the exit port were recorded at speed of 3500 rpm

for selected range of equivalence ratios while when engine was operated at very high

speed, the NOx concentrations were lower than at 3500 rpm. The peak concentrations when

engine was near stoichiometric ratio or slight when fuel mixture was rich. The variation of

NOx levels measured in the exhaust port is plotted for various equivalence ratios as shown

in the Figure 8.22.

11/3/2009

NOx plot.grf

Fuel/Air Equivalence Ratio

NO

x C

once

ntra

tion

(ppm

) in

IC E

ngin

e Ex

haus

t

0 0.2 0.4 0.6 0.8 1 1.2 1.425

50

75

100

125

150

175

200

225

250

NOx (2000 r.p.m)NOx (2500 r.p.m)NOx (3500 r.p.m)NOx (7000 r.p.m)

236

Figure 8.23 shows the levels of NOx measured at the various distances from the exit port.

Theses measurement were done using multiple set of Flue Gas Analyzer (Testo 350-XL)

along with the Temperature recorded near the exit port.

Figure 8.23 NOx Levels at Various Distances from the Exhaust Port engine Operating at 3000 rpm.

Higher concentrations of NOx were recorded when the exit port temperature was higher.

The NOx concentration shows stable and constant behavior after 20 cm from the exit port

which shows that NOx chemistry freezes as the temperature falls.

Carbon monoxide (CO) is very critical criteria gaseous pollutant which has serious

health concerns when exist at elevated concentrations in atmosphere. The incomplete

combustion of hydrocarbon fuels in internal combustion engine is major source of CO

emissions.

In present study, both in-cylinder and exhaust measurements of CO were carried

out. The exhaust levels of CO were measured by online Emission Analyzer (Model Testo-

350) while In-cylinder measurements were done through Rapid Sampling Valve. The

11/5/2009

NOx Plot Varius Temp.grf

Distance from Engine Exhaust Valve,cm

Exha

ust N

Ox

(NO

+NO

2) C

once

ntra

tions

, ppm

0 20 40 60 80 100 1200

25

50

75

100

125

150

175

Te(200°C)Te(250°C)Te(350°C)Te(400°C)Te(600°C)

237

levels of CO were monitored at two points 1) within the cylinder by rapid sampling valve

mounted near the spark plug and secondly at the exit port.

Figure 8.24 shows the measurements of CO levels (measured in term of % age while it is

then converted to mole fraction and ppm units). The data is plotted against crank angle

position. For Fuel-A and Fuel-B, first CO data was recorded at nearly -8° (7.8° actual)

while for Fuel-C, data was recorded at -13°. This indicates the early start of combustion

when Fuel-C was used and lower molar fraction shows the maximum conversion of fuel to

combustion product (CO2 and water). The varying levels of CO for Fuel-A and Fuel-B after

combustion process shows the occurring of some reactions CO consumption formed during

the combustion phase and freezing of CO chemistry when used Fuel-C

238

Figure 8.24 Measured CO Concentrations (In-Cylinder) for Three Fuel (3000

rev/min, φ=1.0 and Pinlet =0.67 atm) The variation in CO concentrations at the exit port and in-cylinder concentration are shown

in Figure 8.25 and Figure 8.26 respectively. These plots provided the comparison of CO

levels for experimental data recorded for three types of experimental condition in which

three fuels were fired.

Crank rotation angle

Mea

sure

d In

-Cyl

inde

r CO

Con

cent

ratio

ns (M

ole

Frac

tion)

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

Fuel-A

Crank rotation angle

Mea

sure

d In

-Cyl

inde

r CO

Con

cent

ratio

ns (M

ole

Frac

tion)

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.003

0.006

0.009

0.012

0.015

0.018

0.021

0.024

0.027

0.03

0.033

Fuel-B

Crank rotation angle

Mea

sure

d In

-Cyl

iner

Con

cent

ratio

ns (M

ole

Frac

tion)

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

0.004

0.0045

0.005

0.0055

Fuel-C

239

.

Figure 8.25 Variation in CO Emissions from CNG fired IC Engine (Speed; 3000 rpm,

Texit=300 °C) The experiments were conducted with each fuel for various equivalence ratios and data was

recorded when engine was operated at 3000 rpm and exit temperature was nearly 300 °C.

Figure 8.26 depict those CO concentrations rapidly increased during when engine was

operated at equivalence ratio of 0.9 and when equivalence ratio was further increased up to

1.4 under fuel rich conditions, the CO levels rise more sharply which directly indicate the

in-complete combustion each of the fuel. The degree of completion of the combustion if

less with the Fuel-A. If we examine the Figure 8.25 and Figure 8.26, higher levels of CO

were recorded for the commercial CNG fuel (Fuel-A) than other methane containing

gaseous fuels (Fuel-B and Fuel-C). If we look at both figures (Figure 8.25 and Figure 8.26)

collectively, the levels of CO measured at the exit port are lower than the maximum values

measured within the combustion chamber.

Fuel/Air Equivalence Ratio

CO

Con

cent

ratio

ns in

Exh

aust

, ppm

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.40

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000

Fuel-AFuel-BFuel-C

240

Figure 8.26 Variation in CO Concentrations (In-Cylinder) from CNG fired IC Engine

(Speed; 3000 rpm) The change in concentrations of CO of burned gas mixture within the combustion chamber

and when this mixture flows out through the exhaust valve is shown in Box-Whicker Plot

for three fuels. Figure 8.27 gives the variation of CO concentrations for within cylinder and

in the exit port near the exhaust valve. In this Fuel-A has maximum change in the

concentrations when burned gas mixture within the cylinder and when flows out through

the exhaust valve. The temperature of this mixture falls rapidly and we have observed

lower levels of CO at the exit port. This indicates the freeze of CO chemistry as the

temperature fall and burned mixture become cool. This prediction is also supported by the

data shown in Figure 8.28 which shows how the lowering of temperature in the exhaust

affects the CO levels. As the temperature decreased, the CO levels become nearly constant.

Fuel/Air Equivalence Ratio

CO

Con

cent

artio

ns (I

n-C

ylin

der)

, ppm

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.40

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

55000

Fuel-AFuel-BFuel-C

241

Figure 8.27 Variation of Ratio of In-Cylinder and Exhaust Concentrations of Oxides

of Nitrogen (NOx) for Three Fuels. Figure 8.28 CO Levels at Various Distances from the Exhaust Port engine Operating

at 3000 rpm for Fuel-A (Commercial CNG)

Rat

io o

f In-

Cyl

inde

r to

Exha

ust C

once

ntra

tions

of C

O

Fuel-A Fuel-B Fuel-C0

8

16

24

32

40

48

56

64

72

80

MaximumMinimum75%25%MedianOutliersExtremes

11/5/2009

Distance from Engine Exhaust Valve,cm

Exha

ust C

O C

once

ntra

tions

, ppm

0 20 40 60 80 100 1200

250

500

750

1000

1250

1500

1750

Te(200°C)Te(250°C)Te(350°C)Te(400°C)Te(600°C)

242

Figure 8.29 Measured CO in Engine Exhaust at various Engine Speeds for Fuel-A

The engine speed showed little effect on the CO concentrations measured near the exit port

close to the exhaust valve. Figure 8.29 showed the results of exhaust concentrations

measured for various equivalence ratios when engine was fired with Fuel-A and showed

the similar pattern of CO profiles.

The molded data of CO was also determined for the four proposed kinetic mechanisms

using IC engine module of Chemkin 4.1.1 software. The simulation conditions were set as

given in Table 8.2 and fuels fractions were used as given for Fuel-A in Table 8.1. The

modeled data was compared with the experimental data (collected when engine was

operated at 3000 rpm, φ=1.0, Pinlet=0.67 atm fired with Fuel-A) and Figure 8.30

11/5/2009

CO Plot.grf

Fuel/Air Equivalence Ratio

Mea

sure

d C

O C

once

ntra

tions

(ppm

) Clo

sed

to E

xhau

st V

alve

of I

C E

ngin

e

0 0.2 0.4 0.6 0.8 1 1.2 1.40

2000

4000

6000

8000

10000

CO (2000 r.p.m)CO (2500 r.p.m)CO (3500 r.p.m)CO (7000 r.p.m)

243

Figure 8.30 Comparison of CO Profiles (with Modeled data and Experimental data).

shows the comparison of modeled data for CO levels obtained for four proposed kinetic

mechanisms. The profile for mechanism-I and mechanism-II shows very early start of the

combustion, which does not agree with the experimental data. Mechanism-III also shows

far away behavior from the actual monitored data of the actual engine operation data.

According to Figure 8.30, the molded data for Mechanism-IV exhibits closer agreement

with experimental measurements. Although there are some discrepancies exist in the CO

profiles for Mechanism-IV and experimental data but on whole, we can conclude the

Mechanism-IV is representative scheme of reactions predicting the combustion in CNG

fired IC engine.

The major reactions involved in formation and consumption of CO in the combustion

chamber of the tested automobile (IC) engine for proposed kinetic mechanism. The

Crank rotation angle

In-C

ylin

der C

O L

evel

s, M

ole

Frac

tion

-150 -120 -90 -60 -30 0 30 60 90 120 1500

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

0.055

0.06

0.065

0.07

0.075

0.08

Mechanism-IMechansim-IIMechansim-IIIMechansim-IVExperimental data

244

reactions are listed according to the normalized rate of production coefficient determined

by the Rate of Production Analysis (ROP) in Chemkin 4.1.1.

According to Table 8.4 the following reaction were proposed to take part in the

formation of CO and shows more contribution) during the combustion of CNG in tested IC

engine;

R-141 HNCO+M<=>NH+CO+M,

R-205 NCO+M<=>N+CO+M).

Table 8.4 Reactions in Four Kinetic Mechanisms (Proposed) in CO Formation and

Consumption Mechanism Reactions Normalized Rate of

Production Coefficient

Mechanism-I

R-782. CO+N2O<=>CO2+N2

R-783. CO2+N<=>NO+CO

R-870. HNCO+M<=>NH+CO+M

R-934. NCO+M<=>N+CO+M

-0.139

0.740

0.322

1.000

Mechanism-II

R-640. CO+N2O<=>CO2+N2

R-641. CO2+N<=>NO+CO

R-708. HCN+O<=>NH+CO

R-718. NCO+H<=>NH2+CO

R-728. HNCO+M<=>NH+CO+M

R-737. H+NCO<=>NH+CO

R-753. O+CN<=>CO+N

R-754. O+NCO<=>NO+CO

R-763. OH+NCO<=>NO+CO+H

R-791. NCO+M<=>N+CO+M

-0.013

0.094

0.044

0.119

-0.025

0.304

-0.017

0.290

0.138

-0.945

245

Mechanism-III

R-711. CO+N2O<=>CO2+N2

R-712. CO2+N<=>NO+CO

R-779. HCN+O<=>NH+CO

R-789. HNCO+H<=>NH2+CO

R-808. H+NCO<=>NH+CO

R-826. O+NCO<=>NO+CO

R-835. OH+NCO<=>NO+CO+H

R-863. NCO+M<=>N+CO+M

-0.032

-0.713

0.020

0.056

0.250

0.383

0.285

-0.246

Mechanism-IV

R-141. HNCO+M<=>NH+CO+M

R-177. OH+NCO<=>NO+CO+H

R-205. NCO+M<=>N+CO+M

0.975

0.022

1.000

8.5 Summary:

The simulation predicted that for the fuel leaner condition (φ ≈0.6), maximum

cylinder reached to about 18.0 atm and significant rised to about 40.0 atm for fuel rich

condition when equivalence ratio varied form φ=1.13 to 1.3. For fuel rich conditions, high

concentrations of CO were observed while NOx levels were lowered while leaner mixture

produced lower CO emissions and moderate levels of NOx emissions. The modeled data

was compared with the experimental data (collected when engine was operated at 3000

rpm, φ=1.0, Pinlet=0.67 atm. The NOx and CO profile for Mechanism-I, Mechanism-II and

Mechanism III respectively depicted that these mechanisms seem to be inappropriate for

predicting the emissions IC engine. The molded data for Mechanism-IV exhibits closer

agreement with experimental measurements. Through the rate of production analysis,

important reactions in each mechanism were identified as contributing towards the

predicted profiles pollutant species. Although each proposed mechanism illustrated some

discrepancies among the each profile, Mechanism-IV (consisting of 208 reactions and 78

species) showed good agreement with experimental data for pressure, temperature and

pollutant species profiles.

246

Conclusion and Proposed Future Work:

1. The present work establishes that the kinetic reaction mechanisms can be used

to predict the formation of pollutants such as CO, NO, NO2 and NH3 in CNG

fired automobile engine (which is type of IC engines).

2. The reaction mechanisms of CNG combustion, used in present study, were

developed by coupling of two mechanisms (i) a hydrocarbon reaction

mechanism generated by EXGAS (an automatic mechanism generation tool)

and (ii) Leeds NOx mechanisms. Four reaction mechanisms successfully

showed the capability of predicting combustion of CNG in automobile engine.

These mechanisms were classified as “Mechanism-I, Mechanism-II

Mechanism-III and Mechanism-IV in the present study.

3. The mechanisms used in present study, were containing the following types of

primary reactions Unimolecular initiation, Bimolecular initiation (Addition

with oxygen, Only one addition or two 2nd addition globalized), Beta-scission

(C-H bond breaking, C-C bond breaking), Isomerizations, Decomposition to o-

ring, Oxidation, Metatheses, Combinations and Disproportionations. The

number of individual types of reactions is varied in each of the proposed

mechanisms.

4. The Mechanism-I is a comprehensive reaction mechanism containing reactions

feasible at range of temperature conditions (below 800 K and above 1000 K).

This mechanism is composed of 935 elementary reactions and 185 species.

Mechanism-II is a high temperature (above 1000 K) reaction mechanism and

consists of 124 species and 792 elementary reactions. This mechanism is

composed of that type of reaction feasibly at high temperature during the

247

combustion of natural gas. Mechanism-III is a low temperature (below 800 K)

reaction mechanism and consists of 152 species and 864 elementary reaction.

Mechanism-IV is reduced form of Mechanism-I and this reduction was done by

the chemical lumping technique. This mechanism is consisting of chemical

reactions feasible both low to high temperature ranges i.e. below 800 K and

above 1000 K and is consisting of 72 species and 208 elementary reactions.

5. The simulation of natural gas combustion by four proposed mechanisms

predicted the adiabatic flame temperatures of mostly of order ~6300 K, 4400 K,

6200 K and 8200 K for Mechanism-I, Mechanism-II, Mechanism-III and

Mechanism-IV respectively. It was also observed that adiabatic flame

temperatures increase with increasing initial gas temperature

6. The pressure and temperature profiles obtained with Mechanism-I showed the

uneven behavior of variation under the selected simulation conditions. The trend

of the curves shows the abnormal combustion reaction occurrence which

indicates the knocking phenomena. The combustion reactions occur three times

when combustion is simulated with Mechanism-II and Mechanism-III and each

of the profiles shows the early start of combustion during the complete engine

cycle (-150° to 150°).

7. Mechanism-IV predicted the almost smooth pressure profile which indicates the

normal combustion occurrence in the combustion chamber of IC engine. This

concludes that this mechanism consists of the reactions which would be the

representative of the combustion of natural gas. The experimental data of

cylinder pressure also exhibited the similar trend as that of observed in

simulation studies on Mechanism-IV.

248

8. The predicted CO profiles illustrate that high temperature (Mechanism-II) and

low temperature (Mechanism-III) mechanism showed the early CO formation

which indicate that these mechanisms contains the reactions which have low

activation energy and results do not agree with the experimental measurements.

Mechanism-I and Mechanism-IV indicate the start of combustion at -7.6° and -

13.2° respectively which occur during the combustion phase of engine cycle and

agreed with the experimentally measured results of start of ignition flame in IC

engine combustion chamber. The peak CO molar fractions achieved near -2.68°

of crank rotation angle at the end combustion reactions with Mechanism-I and

Mechanism-IV. The CO profiles (Mechanism-I & Mechanism-IV) indicate that

both mechanisms contain such types of reactions which govern the reactions in

the formation of CO in combustion chamber of IC engine.

9. The simulation data of NO molar fraction profiles showed the discrepancies in

the formation reactions. NO profiles of high and low temperature mechanisms

i.e. Mechanism-II & Mechanism-III. They exhibited the incomparable and

unpredictable pattern while complete and simplified mechanism with medium

temperature ranges (1000-2000 K) mechanisms (Mechanism-I & Mechanism-

IV). Also, the Mechanism-II & Mechanism-III indicate the early start of

formation reactions NO with the selected simulation conditions. The

Mechanism-I and Mechanism-IV showed the start of NO formation nearly at -

7.18° of crank position angle and peak molar fractions reached at nearly 2.68°

of crank position angle at the end of the combustion process.

10. The Rate of Production Analysis (ROP) and Sensitivity Analysis (SA) of four

kinetic mechanisms were carried out at two temperature conditions of 1500 K

and 4000 K. The major The ROP analysis identified the reactions contributing

249

the formation of pollutant species of NO, NO2, NH3, CO and CO2. This analysis

also revealed that different types of reactions are involved at both temperatures.

The total ROP versus crank rotational angle plots indicate that Mechanism-II

(high temperature) and Mechanism-III (low temperature) predict the occurrence

of earlier combustion process in combustion chamber while for Mechanism-I &

Mechanism-IV predict the closer actual engine processes especially combustion

pattern. The sensitivity analysis of the detailed kinetic mechanism identified the

reactions in the mechanisms of which reaction rates influenced the output

concentrations of pollutants species.

11. An experimental studies showed that for the fuel leaner condition (φ ≈0.6),

maximum cylinder pressure reached to about 18.0 atm and maximum pressure

is achieved at about 40.0 atm for equivalence ration of φ=1.13 and 1.3

respectively.

12. The simulated pressure & temperature profiles of Mechanism-I exhibited the

closer agreement with those of the experimental profiles while the pollutant

species profiles significantly deviated. The deviation in the species profile

caused because of the reactions involved in the formation/destruction under

given conditions. Similarly, the profiles of Mechanism-II (high temperature

above 1000K) and Mechanism-III (low temperature below 800 K) exhibited the

early start of the combustion which was not supported by the experimental

measurements. On the basis of these discrepancies, it is conclude that

Mechanism-I, Mechanism-II & Mechanism-III were failed in the prediction of

the formation pollutants and the experimental measurements did not validate the

simulation results.

250

13. In spite of the existence of some discrepancies among the simulation profiles,

Mechanism-IV (consisting of 208 elementary reactions & 72 species) exhibits

the closer agreement with the experimental data under the given engine

operating conditions. This mechanism is containing the reactions feasible at

range of temperature conditions of low (below 800 K) to high (1000 K). In this

mechanism, major primary types of reactions include; Unimolecular initiations,

Bimolecular initiations, Beta-scissions, Oxidation, Branching, Metatheses,

Combination and Dismutation. On the basis of this, it is concluded that

Mechanism-IV is consisting of those kinds elementary reactions (both primary

& secondary type) involved in the combustion of CNG in the automobile engine

and is capable of predicting the formation of the selected criteria gaseous

pollutants.

Original Contributions:

• Simulation based study of natural gas combustion (a multi-component gas phase

mixture) in IC engine using the kinetic mechanisms.

• The development and the analysis of kinetic mechanisms for prediction of

pollutants (such as CO, NO, NO2, and NH3) formation in combustion chamber of

IC engine.

• Study of methane oxidation in IC engine using the kinetic mechanisms of GRI3.0,

UBC 2.0, Jones and Lindstedt four-step & Global mechanism.

• An experimental setup was developed for the validation of simulation based results

and to select the appropriate kinetic mechanism through experimental data.

• Investigation of proposed reaction mechanism using the (i) Rate of Production

Analysis (ii) Sensitivity Analysis and (iii) Uncertainty Analysis of proposed

251

reaction mechanisms of natural gas combustion in IC engine were carried out to

identify the reactions involved in the formation of pollutant species of CO, NO,

NO2, and NH3.

Proposed Future Work:

• Study of the kinetic reaction mechanisms to design & develop of the clean engine

technology by controlling the emission at source (i.e. during the formation).

• The development of a computer code (software) that couple the reaction

mechanisms of different scenarios automatically compatible to the kinetic

simulation software (such as Chemkin, Kinetus etc ) and CFD modules such as

ANSYS, Fluent etc.

• Development of computer algorithm (computer software) that harmonizes the

approaches of available software for the development detailed kinetic mechanisms

and software available for automatic simplification of these mechanisms to reduced

form (with few reaction steps).

252

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Annexure-I

(Proposed Kinetic Mechanisms) [“A” has units of (mole-cm-sec-K) and “Ea” has units of (cal/mole)]

264

Mechanism-I (Complete) Rex No Reaction A b Ea

Rex No Reaction A b Ea

1 C3H8=>R4CH3+R11C2H5 9.40E+16 0 86154.2 35 R34C4H8OOOOH=R47C4H7O4H2 3.30E+09 1 32500 2 C3H8+O2=>R3OOH+R21C3H7 1.40E+13 0 50323.7 36 R34C4H8OOOOH=R48C4H7O4H2 5.70E+08 1 23000 3 C3H8+O2=>R3OOH+R19C3H7 4.20E+13 0 53033 37 R34C4H8OOOOH=R49C4H8OOOOH 8.50E+06 1 24000 4 R19C3H7+O2=R22C3H7OO 9.00E+18 -2.5 0 38 R35C4H8OOOOH=R50C4H7O4H2 5.70E+08 1 32500 5 R20C4H9+O2=R23C4H9OO 9.00E+18 -2.5 0 39 R35C4H8OOOOH=R51C4H7O4H2 9.90E+07 1 20000 6 R21C3H7+O2=R24C3H7OO 1.60E+19 -2.5 0 40 R37C3H6OOOOH=R53C3H5O4H2 1.70E+09 1 27500 7 R25C3H6OOH+O2=R31C3H6OOOOH 1.70E+19 -2.5 0 41 R37C3H6OOOOH=R38C3H5O4H2 8.60E+08 1 28000 8 R26C3H6OOH+O2=R32C3H6OOOOH 9.00E+18 -2.5 0 42 R42C4H7O4H2=R45C4H7O4H2 8.60E+08 1 25800 9 R27C4H8OOH+O2=R33C4H8OOOOH 1.80E+19 -2.5 0 43 R43C4H8OOOOH=R54C4H7O4H2 1.70E+09 1 27500

10 R28C4H8OOH+O2=R34C4H8OOOOH 1.70E+19 -2.5 0 44 R43C4H8OOOOH=R44C4H7O4H2 5.70E+08 1 25000 11 R29C4H8OOH+O2=R35C4H8OOOOH 9.00E+18 -2.5 0 45 R43C4H8OOOOH=R45C4H7O4H2 1.50E+08 1 25000 12 R30C3H6OOH+O2=R37C3H6OOOOH 1.50E+18 -2.5 0 46 R46C4H7O4H2=R48C4H7O4H2 5.70E+08 1 15300 13 R36C4H8OOH+O2=R52C4H8OOOOH 1.00E+19 -2.5 0 47 R49C4H8OOOOH=R46C4H7O4H2 1.50E+08 1 25000 14 R55C4H8OOH+O2=R43C4H8OOOOH 1.50E+18 -2.5 0 48 R49C4H8OOOOH=R47C4H7O4H2 3.30E+09 1 35500 15 R57C4H8OOH+O2=R49C4H8OOOOH 9.00E+18 -2.5 0 49 R49C4H8OOOOH=R56C4H7O4H2 2.90E+08 1 20000 16 R63C4H8OOH+O2=R65C4H8OOOOH 9.50E+18 -2.5 0 50 R52C4H8OOOOH=R58C4H7O4H2 3.30E+09 1 32500 17 R64C4H9+O2=R61C4H9OO 1.70E+19 -2.5 0 51 R52C4H8OOOOH=R59C4H7O4H2 5.70E+08 1 25000 18 R22C3H7OO=R25C3H6OOH 3.30E+09 1 32500 52 R52C4H8OOOOH=R60C4H7O4H2 1.50E+08 1 25000 19 R22C3H7OO=R26C3H6OOH 8.60E+08 1 28000 53 R61C4H9OO=R55C4H8OOH 5.00E+09 1 35500 20 R23C4H9OO=R27C4H8OOH 3.30E+09 1 32500 54 R55C4H8OOH=R57C4H8OOH 8.60E+08 1 19800 21 R23C4H9OO=R28C4H8OOH 5.70E+08 1 25000 55 R61C4H9OO=R57C4H8OOH 8.60E+08 1 28000 22 R23C4H9OO=R29C4H8OOH 1.50E+08 1 25000 56 R60C4H7O4H2=R62C4H7O4H2 2.90E+08 1 12300 23 R24C3H7OO=R30C3H6OOH 1.00E+10 1 35500 57 R61C4H9OO=R63C4H8OOH 3.30E+09 1 32500 24 R29C4H8OOH=R36C4H8OOH 5.70E+08 1 15300 58 R65C4H8OOOOH=R66C4H7O4H2 8.60E+08 1 35500 25 R31C3H6OOOOH=R38C3H5O4H2 5.00E+09 1 35500 59 R65C4H8OOOOH=R67C4H7O4H2 1.70E+09 1 27500 26 R31C3H6OOOOH=R39C3H5O4H2 3.30E+09 1 30500 60 R25C3H6OOH=>R3OOH+C3H6Y 8.50E+12 0 26000 27 R31C3H6OOOOH=R37C3H6OOOOH 4.90E+07 1 25000 61 R27C4H8OOH=>R3OOH+C4H8Y 8.50E+12 0 26000 28 R32C3H6OOOOH=R40C3H5O4H2 3.30E+09 1 32500 62 R30C3H6OOH=>R3OOH+C3H6Y 8.50E+12 0 26000 29 R32C3H6OOOOH=R41C3H5O4H2 5.70E+08 1 23000 63 R36C4H8OOH=>R2OH+C3H7CHO 1.00E+09 0 7500 30 R33C4H8OOOOH=R42C4H7O4H2 3.30E+09 1 30500 64 R39C3H5O4H2=>R3OOH+C3H5OOHZ 8.50E+12 0 26000 31 R33C4H8OOOOH=R43C4H8OOOOH 4.90E+07 1 25000 65 R39C3H5O4H2=>R2OH+C2H4CHOOOH 1.00E+09 0 7500 32 R33C4H8OOOOH=R44C4H7O4H2 3.30E+09 1 32500 66 R40C3H5O4H2=>R3OOH+C3H5OOHZ 1.70E+13 0 26000 33 R33C4H8OOOOH=R45C4H7O4H2 8.60E+08 1 28000 67 R42C4H7O4H2=>R3OOH+C4H7OOHZ 8.50E+12 0 2600034 R34C4H8OOOOH=R46C4H7O4H2 5.00E+09 1 35500 68 R42C4H7O4H2=>R2OH+C3H6CHOOOH 1.00E+09 0 7500

265

Rex No Reaction A b Ea

Rex No Reaction A b Ea

69 R46C4H7O4H2=>R3OOH+C4H7OOHZ 8.50E+12 0 26000 103 R48C4H7O4H2=>R2OH+C4H7O#4OOH 9.20E+10 0 16600 70 R47C4H7O4H2=>R3OOH+C4H7OOHZ 8.50E+12 0 26000 104 R50C4H7O4H2=>R2OH+C4H7O#3OOH 6.10E+11 0 17950 71 R47C4H7O4H2=>R3OOH+C4H7OOHZ 8.50E+12 0 26000 105 R50C4H7O4H2=>R2OH+C4H7O#4OOH 9.20E+10 0 16600 72 R51C4H7O4H2=>R2OH+C3H6CHOOOH 1.00E+09 0 7500 106 R51C4H7O4H2=>R2OH+C4H7O#5OOH 3.60E+09 0 7000 73 R53C3H5O4H2=>R3OOH+C3H5OOHY 8.50E+12 0 26000 107 R53C3H5O4H2=>R2OH+C3H5O#3OOH 6.10E+11 0 17950 74 R53C3H5O4H2=>R2OH+C2H5COOOH 1.00E+09 0 7500 108 R54C4H7O4H2=>R2OH+C4H7O#3OOH 6.10E+11 0 17950 75 R54C4H7O4H2=>R3OOH+C4H7OOHY 8.50E+12 0 26000 109 R55C4H8OOH=>R2OH+C4H8O#3 6.10E+11 0 17950 76 R54C4H7O4H2=>R2OH+C3H7COOOH 1.00E+09 0 7500 110 R56C4H7O4H2=>R2OH+C4H7O#4OOH 9.20E+10 0 16600 77 R55C4H8OOH=>R3OOH+C4H8Y 8.50E+12 0 26000 111 R57C4H8OOH=>R2OH+C4H8O#4 9.20E+10 0 16600 78 R58C4H7O4H2=>R3OOH+C4H7OOHZ 1.70E+13 0 26000 112 R58C4H7O4H2=>R2OH+C4H7O#3OOH 6.10E+11 0 17950 79 R62C4H7O4H2=>R2OH+C3H7COOOH 2.00E+09 0 7500 113 R59C4H7O4H2=>R2OH+C4H7O#4OOH 9.20E+10 0 16600 80 R63C4H8OOH=>R3OOH+C4H8Y 8.50E+12 0 26000 114 R60C4H7O4H2=>R2OH+C4H7O#5OOH 3.60E+09 0 7000 81 R67C4H7O4H2=>R3OOH+C4H7OOHY 8.50E+12 0 26000 115 R63C4H8OOH=>R2OH+C4H8O#3 6.10E+11 0 17950 82 R67C4H7O4H2=>R2OH+C3H7COOOH 1.00E+09 0 7500 116 R66C4H7O4H2=>R2OH+C4H7O#3OOH 6.10E+11 0 17950 83 R25C3H6OOH=>R2OH+C3H6O#3 6.10E+11 0 17950 117 R66C4H7O4H2=>R2OH+C4H7O#4OOH 9.20E+10 0 16600 84 R26C3H6OOH=>R2OH+C3H6O#4 9.20E+10 0 16600 118 R67C4H7O4H2=>R2OH+C4H7O#3OOH 6.10E+11 0 17950 85 R27C4H8OOH=>R2OH+C4H8O#3 6.10E+11 0 17950 119 R21C3H7+O2=>C3H6Y+R3OOH 2.30E+12 0 5000 86 R28C4H8OOH=>R2OH+C4H8O#4 9.20E+10 0 16600 120 B1O+C3H8=>R2OH+R21C3H7 2.60E+13 0 5200 87 R29C4H8OOH=>R2OH+C4H8O#5 3.60E+09 0 7000 121 B1O+C3H8=>R2OH+R19C3H7 1.00E+14 0 7850 88 R30C3H6OOH=>R2OH+C3H6O#3 6.10E+11 0 17950 122 C3H8+R1H=>H2+R21C3H7 9.00E+06 2 5000 89 R38C3H5O4H2=>R2OH+C3H5O#3OOH 6.10E+11 0 17950 123 C3H8+R1H=>H2+R19C3H7 5.70E+07 2 7700 90 R38C3H5O4H2=>R2OH+C3H5O#4OOH 9.20E+10 0 16600 124 C3H8+R2OH=>H2O+R21C3H7 2.60E+06 2 -765 91 R39C3H5O4H2=>R2OH+C3H5O#3OOH 6.10E+11 0 17950 125 C3H8+R2OH=>H2O+R19C3H7 5.40E+06 2 450 92 R40C3H5O4H2=>R2OH+C3H5O#3OOH 6.10E+11 0 17950 126 C3H8+R3OOH=>H2O2+R21C3H7 4.00E+11 0 15500 93 R41C3H5O4H2=>R2OH+C3H5O#4OOH 9.20E+10 0 16600 127 C3H8+R3OOH=>H2O2+R19C3H7 1.20E+12 0 17000 94 R42C4H7O4H2=>R2OH+C4H7O#3OOH 6.10E+11 0 17950 128 C3H8+R4CH3=>CH4+R21C3H7 2.00E+11 0 9600 95 R44C4H7O4H2=>R2OH+C4H7O#3OOH 6.10E+11 0 17950 129 C3H8+R4CH3=>CH4+R19C3H7 6.00E-01 4 8200 96 R44C4H7O4H2=>R2OH+C4H7O#4OOH 9.20E+10 0 16600 130 C3H8+R5CHO=>HCHO+R21C3H7 1.00E+07 2 17000 97 R45C4H7O4H2=>R2OH+C4H7O#4OOH 9.20E+10 0 16600 131 C3H8+R5CHO=>HCHO+R19C3H7 2.00E+05 3 18500 98 R45C4H7O4H2=>R2OH+C4H7O#5OOH 3.60E+09 0 7000 132 C3H8+R6CH2OH=>CH3OH+R21C3H7 6.00E+01 3 12000 99 R46C4H7O4H2=>R2OH+C4H7O#3OOH 6.10E+11 0 17950 133 C3H8+R6CH2OH=>CH3OH+R19C3H7 2.00E+02 3 14000

100 R46C4H7O4H2=>R2OH+C4H7O#5OOH 3.60E+09 0 7000 134 C3H8+R7CH3O=>CH3OH+R21C3H7 1.50E+11 0 4500 101 R47C4H7O4H2=>R2OH+C4H7O#3OOH 6.10E+11 0 17950 135 C3H8+R7CH3O=>CH3OH+R19C3H7 3.20E+11 0 7300 102 R47C4H7O4H2=>R2OH+C4H7O#3OOH 6.10E+11 0 17950 136 C3H8+R8CH3OO=>CH3OOH+R21C3H7 3.00E+12 0 17500

266

Rex No Reaction A b Ea

Rex No Reaction A b Ea

137 C3H8+R8CH3OO=>CH3OOH+R19C3H7 1.20E+13 0 20000 171 C4H10+R2OH=>H2O+R11C2H5+C2H4Z 7.80E+06 2 -765

138 C3H8+R11C2H5=>C2H6+R21C3H7 2.00E+11 0 11000 172 C4H10+R3OOH=>H2O2+R11C2H5+C2H4Z 1.20E+12 0 15500

139 C3H8+R11C2H5=>C2H6+R19C3H7 6.00E+11 0 13500 173 C4H10+R4CH3=>CH4+R11C2H5+C2H4Z 6.00E+11 0 9600

140 C3H8+R21C3H7=>C3H8+R19C3H7 8.40E-03 4.2 8700 174 C4H10+R8CH3OO=>CH3OOH+R11C2H5+C2H4Z 4.50E+12 0 17500

141 R1H+R21C3H7=>C3H8 8.30E+12 0 0 175 C4H10+R11C2H5=>C2H6+R11C2H5+C2H4Z 6.00E+11 0 11000

142 R2OH+R21C3H7=>C3H7OH 5.90E+12 0 0 176 C5H12+R1H=>H2+R4CH3+2C2H4Z 2.70E+07 2 5000

143 R3OOH+R21C3H7=>C3H7OOH 4.80E+12 0 0 177 C5H12+R2OH=>H2O+R4CH3+2C2H4Z 7.80E+06 2 -765

144 R4CH3+R21C3H7=>C4H10 1.50E+13 0 0 178 C5H12+R3OOH=>H2O2+R4CH3+2C2H4Z 1.20E+12 0 15500

145 R5CHO+R21C3H7=>C3H7CHO 5.20E+12 0 0 179 C5H12+R4CH3=>CH4+R4CH3+2C2H4Z 6.00E+11 0 9600

146 R6CH2OH+R21C3H7=>C4H9OH 5.10E+12 0 0 180 C5H12+R8CH3OO=>CH3OOH+R4CH3+2C2H4Z 4.50E+12 0 17500

147 R7CH3O+R21C3H7=>C4H10O 4.90E+12 0 0 181 C5H12+R11C2H5=>C2H6+R4CH3+2C2H4Z 6.00E+11 0 11000

148 R8CH3OO+R21C3H7=>C4H10OO 4.40E+12 0 0 182 C6H14+R1H=>H2+R11C2H5+2C2H4Z 2.70E+07 2 5000

149 R11C2H5+R21C3H7=>C5H12 5.20E+12 0 0 183 C6H14+R2OH=>H2O+R11C2H5+2C2H4Z 7.80E+06 2 -765

150 R21C3H7+R21C3H7=>C6H14 2.30E+12 0 0 184 C6H14+R3OOH=>H2O2+R11C2H5+2C2H4Z 1.20E+12 0 15500

151 R22C3H7OO+R3OOH=>C3H7OOH+O2 2.00E+11 0 -1300 185 C6H14+R4CH3=>CH4+R11C2H5+2C2H4Z 6.00E+11 0 9600

152 R23C4H9OO+R3OOH=>C4H9OOH+O2 2.00E+11 0 -1300 186 C6H14+R8CH3OO=>CH3OOH+R11C2H5+2C2H4Z 4.50E+12 0 17500

153 R24C3H7OO+R3OOH=>C3H7OOH+O2 2.00E+11 0 -1300 187 C6H14+R11C2H5=>C2H6+R11C2H5+2C2H4Z 6.00E+11 0 11000

154 R61C4H9OO+R3OOH=>C4H9OOH+O2 2.00E+11 0 -1300 188 C3H6O#3+R1H=>H2+CH2COZ+R4CH3 2.70E+07 2 5000

155 C3H5OOHZ=>R2OH+HCHO+R10C2H3V 1.50E+16 0 42000 189 C3H6O#3+R2OH=>H2O+CH2COZ+R4CH3 7.80E+06 2 -765

156 C4H7OOHZ=>R2OH+CH3CHO+R10C2H3V 1.50E+16 0 42000 190 C3H6O#3+R3OOH=>H2O2+CH2COZ+R4CH3 1.20E+12 0 15500

157 C3H5OOHY=>R2OH+HCHO+R10C2H3V 1.50E+16 0 42000 191 C3H6O#3+R4CH3=>CH4+CH2COZ+R4CH3 6.00E+11 0 9600

158 C4H7OOHY=>R2OH+CH3CHO+R10C2H3V 1.50E+16 0 42000 192 C3H6O#3+R8CH3OO=>CH3OOH+CH2COZ+R4CH3 6.00E+11 0 9600

159 C3H7OOH=>R2OH+HCHO+R11C2H5 1.50E+16 0 42000 193 C3H6O#3+R11C2H5=>C2H6+CH2COZ+R4CH3 6.00E+11 0 11000

160 C4H9OOH=>R2OH+CH3CHO+R11C2H5 1.50E+16 0 42000 194 C4H8O#3+R1H=>H2+CH2COZ+R11C2H5 2.70E+07 2 5000

161 C2H5COOOH=>R2OH+HCHO+B2CO+R4CH3 1.50E+16 0 42000 195 C4H8O#3+R2OH=>H2O+CH2COZ+R11C2H5 7.80E+06 2 -765

162 C3H7COOOH=>R2OH+HCHO+B2CO+R11C2H5 1.50E+16 0 42000 196 C4H8O#3+R3OOH=>H2O2+CH2COZ+R11C2H5 1.20E+12 0 15500

163 C2H4CHOOOH=>R2OH+CH3CHO+R5CHO 1.50E+16 0 42000 197 C4H8O#3+R4CH3=>CH4+CH2COZ+R11C2H5 6.00E+11 0 9600

164 C3H6CHOOOH=>R2OH+CH3CHO+R13CH2CHO 1.50E+16 0 42000 198 C4H8O#3+R8CH3OO=>CH3OOH+CH2COZ+R11C2H5 6.00E+11 0 9600

165 C3H5O#3OOH=>R2OH+HCHO+R13CH2CHO 1.50E+16 0 42000 199 C4H8O#3+R11C2H5=>C2H6+CH2COZ+R11C2H5 6.00E+11 0 11000

166 C3H5O#4OOH=>R2OH+HCHO+R13CH2CHO 1.50E+16 0 42000 200 C3H6O#4+R1H=>H2+R5CHO+C2H4Z 2.70E+07 2 5000

167 C4H7O#3OOH=>R2OH+HCHO+R5CHO+C2H4Z 1.50E+16 0 42000 201 C3H6O#4+R2OH=>H2O+R5CHO+C2H4Z 7.80E+06 2 -765

168 C4H7O#4OOH=>R2OH+HCHO+R5CHO+C2H4Z 1.50E+16 0 42000 202 C3H6O#4+R3OOH=>H2O2+R5CHO+C2H4Z 1.20E+12 0 15500

169 C4H7O#5OOH=>R2OH+HCHO+R5CHO+C2H4Z 1.50E+16 0 42000 203 C3H6O#4+R4CH3=>CH4+R5CHO+C2H4Z 6.00E+11 0 9600

170 C4H10+R1H=>H2+R11C2H5+C2H4Z 2.70E+07 2 5000 204 C3H6O#4+R8CH3OO=>CH3OOH+R5CHO+C2H4Z 4.50E+12 0 17500

267

Rex No Reaction A b Ea

Rex No Reaction A b Ea

205 C3H6O#4+R11C2H5=>C2H6+R5CHO+C2H4Z 6.00E+11 0 11000 239 C4H8Y+R1H=>.C4H7Y+H2 5.70E+04 3 290

206 C4H8O#4+R1H=>H2+R13CH2CHO+C2H4Z 2.70E+07 2 5000 240 C4H8Y+R2OH=>.C4H7Y+H2O 3.00E+06 2 -1515

207 C4H8O#4+R2OH=>H2O+R13CH2CHO+C2H4Z 7.80E+06 2 -765 241 C4H8Y+R3OOH=>.C4H7Y+H2O2 6.30E+03 3 12400

208 C4H8O#4+R3OOH=>H2O2+R13CH2CHO+C2H4Z 1.20E+12 0 15500 242 C4H8Y+R4CH3=>.C4H7Y+CH4 1.30E+00 4 3575

209 C4H8O#4+R4CH3=>CH4+R13CH2CHO+C2H4Z 6.00E+11 0 9600 243 C4H8Y+R8CH3OO=>.C4H7Y+CH3OOH 2.00E+12 0 17050

210 C4H8O#4+R8CH3OO=>CH3OOH+R13CH2CHO+C2H4Z 4.50E+12 0 17500 244 C4H8Y+R11C2H5=>.C4H7Y+C2H6 1.40E+00 4 4335

211 C4H8O#4+R11C2H5=>C2H6+R13CH2CHO+C2H4Z 6.00E+11 0 11000 245 C3H6Y+B1O=>.C3H5Y+R2OH 9.10E+10 1 3830

212 C4H8O#5+R1H=>H2+R13CH2CHO+C2H4Z 2.70E+07 2 5000 246 C4H8Y+B1O=>.C4H7Y+R2OH 9.10E+10 1 3830

213 C4H8O#5+R2OH=>H2O+R13CH2CHO+C2H4Z 7.80E+06 2 -765 247 .C3H5Y+C4H8Y=>R4CH3+C2H2T+2C2H4Z 6.00E+09 0 11400

214 C4H8O#5+R3OOH=>H2O2+R13CH2CHO+C2H4Z 1.20E+12 0 15500 248 .C3H5Y+C3H6Y=>R10C2H3V+2C2H4Z 6.00E+09 0 11400

215 C4H8O#5+R4CH3=>CH4+R13CH2CHO+C2H4Z 6.00E+11 0 9600 249 .C4H7Y+C4H8Y=>R10C2H3V+3C2H4Z 6.00E+09 0 11400

216 C4H8O#5+R8CH3OO=>CH3OOH+R13CH2CHO+C2H4Z 4.50E+12 0 17500 250 .C4H7Y+C3H6Y=>R4CH3+C2H2T+2C2H4Z 6.00E+09 0 11400

217 C4H8O#5+R11C2H5=>C2H6+R13CH2CHO+C2H4Z 6.00E+11 0 11000 251 C3H7OH+R1H=>H2+R2OH+C3H6Y 9.00E+06 2 5000

218 C3H6O#3+B1O=>R2OH+R5CHO+C2H4Z 7.80E+13 0 5200 252 C3H7OH+R2OH=>H2O+R2OH+C3H6Y 1.30E+06 2 -765

219 C3H6O#4+B1O=>R2OH+R5CHO+C2H4Z 7.80E+13 0 5200 253 C3H7OH+R3OOH=>H2O2+R2OH+C3H6Y 4.00E+11 0 15500

220 C4H8O#3+B1O=>R2OH+R13CH2CHO+C2H4Z 7.80E+13 0 5200 254 C3H7OH+R4CH3=>CH4+R2OH+C3H6Y 2.00E+11 0 9600

221 C4H8O#4+B1O=>R2OH+R13CH2CHO+C2H4Z 7.80E+13 0 5200 255 C3H7OH+R8CH3OO=>CH3OOH+R2OH+C3H6Y 3.00E+12 0 17500

222 C4H8O#5+B1O=>R2OH+R13CH2CHO+C2H4Z 7.80E+13 0 5200 256 C3H7OH+R11C2H5=>C2H6+R2OH+C3H6Y 2.00E+11 0 11000

223 C3H6Y+R1H=>C2H4Z+R4CH3 7.20E+12 0 2900 257 C4H9OH+R1H=>H2+R2OH+C4H8Y 9.00E+06 2 5000

224 C4H8Y+R1H=>C2H4Z+R11C2H5 7.20E+12 0 2900 258 C4H9OH+R1H=>H2+R4CH3+C2H6CO 4.20E+06 2 2400

225 C3H6Y+R2OH=>R4CH3+CH3CHO 1.40E+12 0 -900 259 C4H9OH+R2OH=>H2O+R2OH+C4H8Y 1.30E+06 2 -765

226 C4H8Y+R2OH=>R4CH3+C2H5CHO 1.40E+12 0 -900 260 C4H9OH+R2OH=>H2O+R4CH3+C2H6CO 4.00E+12 0 443

227 C3H6Y+R2OH=>HCHO+R11C2H5 1.40E+12 0 -900 261 C4H9OH+R3OOH=>H2O2+R2OH+C4H8Y 4.00E+11 0 15500

228 C4H8Y+R2OH=>HCHO+R4CH3+C2H4Z 1.40E+12 0 -900 262 C4H9OH+R3OOH=>H2O2+R4CH3+C2H6CO 1.00E+12 0 14000

229 C3H6Y+B1O=>CH2COZ+R4CH3+R1H 3.40E+07 1.8 550 263 C4H9OH+R4CH3=>CH4+R2OH+C4H8Y 2.00E+11 0 9600

230 C4H8Y+B1O=>CH2COZ+R11C2H5+R1H 3.40E+07 1.8 550 264 C4H9OH+R4CH3=>CH4+R4CH3+C2H6CO 1.00E+11 0 7600

231 C3H6Y+R3OOH=>R2OH+C3H6O#3 1.00E+12 0 14400 265 C4H9OH+R8CH3OO=>CH3OOH+R2OH+C4H8Y 3.00E+12 0 17500

232 C4H8Y+R3OOH=>R2OH+C4H8O#3 1.00E+12 0 14400 266 C4H9OH+R11C2H5=>C2H6+R2OH+C4H8Y 2.00E+11 0 11000

233 C3H6Y+R1H=>.C3H5Y+H2 5.70E+04 2.5 290 267 C4H9OH+R11C2H5=>C2H6+R4CH3+C2H6CO 1.00E+11 0 9200

234 C3H6Y+R2OH=>.C3H5Y+H2O 3.00E+06 2 -1515 268 C3H7OH+B1O=>R2OH+R2OH+C3H6Y 9.00E+06 2 5000

235 C3H6Y+R3OOH=>.C3H5Y+H2O2 6.30E+03 2.6 12400 269 C4H9OH+B1O=>R2OH+R2OH+C4H8Y 9.00E+06 2 5000

236 C3H6Y+R4CH3=>.C3H5Y+CH4 1.30E+00 3.5 3575 270 C4H9OH+B1O=>R2OH+R4CH3+C2H6CO 4.20E+06 2 2400

237 C3H6Y+R8CH3OO=>.C3H5Y+CH3OOH 2.00E+12 0 17050 271 C2H5CHO+R1H=>H2+.COC2H5 4.00E+13 0 4200

238 C3H6Y+R11C2H5=>.C3H5Y+C2H6 1.40E+00 3.5 4335 272 C2H5CHO+R2OH=>H2O+.COC2H5 4.20E+12 0 500

268

Rex No Reaction A b Ea

Rex No Reaction A b Ea

273 C2H5CHO+R3OOH=>H2O2+.COC2H5 1.00E+12 0 10000 307 .C3H5Y+R3OOH=>C3H5OOHY 5.00E+12 0 0 274 C2H5CHO+R4CH3=>CH4+.COC2H5 2.00E-06 5.6 2500 308 .C3H5Y+R4CH3=>C4H8Y 1.00E+13 0 0 275 C2H5CHO+R11C2H5=>C2H6+.COC2H5 1.30E+12 0 8500 309 .C3H5Y+R5CHO=>C3H5CHOY 1.00E+13 0 0 276 C2H3CHOZ+R1H=>H2+.COC2H3Z 4.00E+13 0 4200 310 .C3H5Y+R6CH2OH=>C4H7OHY 1.00E+13 0 0 277 C2H3CHOZ+R2OH=>H2O+.COC2H3Z 4.20E+12 0 500 311 .C3H5Y+R8CH3OO=>C4H8OOY 1.00E+13 0 0 278 C2H3CHOZ+R3OOH=>H2O2+.COC2H3Z 1.00E+12 0 10000 312 .C3H5Y+R11C2H5=>C5H10Y 1.00E+13 0 0 279 C2H3CHOZ+R4CH3=>CH4+.COC2H3Z 2.00E-06 5.6 2500 313 .C4H7Y+R1H=>C4H8Y 1.00E+13 0 0 280 C2H3CHOZ+R11C2H5=>C2H6+.COC2H3Z 1.30E+12 0 8500 314 .C4H7Y+R2OH=>C4H7OHY 1.00E+13 0 0 281 C3H7CHO+R1H=>H2+.COC3H7 4.00E+13 0 4200 315 .C4H7Y+R3OOH=>C4H7OOHY 5.00E+12 0 0 282 C3H7CHO+R2OH=>H2O+.COC3H7 4.20E+12 0 500 316 .C4H7Y+R4CH3=>C5H10Y 1.00E+13 0 0 283 C3H7CHO+R3OOH=>H2O2+.COC3H7 1.00E+12 0 10000 317 .C4H7Y+R5CHO=>C4H7CHOY 1.00E+13 0 0 284 C3H7CHO+R4CH3=>CH4+.COC3H7 2.00E-06 5.6 2500 318 .C4H7Y+R6CH2OH=>C5H9OHY 1.00E+13 0 0 285 C3H7CHO+R11C2H5=>C2H6+.COC3H7 1.30E+12 0 8500 319 .C4H7Y+R8CH3OO=>C5H10OOY 1.00E+13 0 0 286 .COC2H5=>B2CO+R11C2H5 2.00E+13 0 28700 320 .C4H7Y+R11C2H5=>C6H12Y 1.00E+13 0 0 287 .COC3H7=>B2CO+R4CH3+C2H4Z 2.00E+13 0 28700 321 .C3H5Y+.C3H5Y=>C6H10Y2 1.00E+13 0 0 288 .COC2H5+O2=>.COOOC2H5 3.00E+19 -2.5 0 322 .C3H5Y+.C4H7Y=>C7H12Y2 1.00E+13 0 0 289 .COC3H7+O2=>.COOOC3H7 3.00E+19 -2.5 0 323 .C4H7Y+.C4H7Y=>C8H14Y2 1.00E+13 0 0 290 .COOOC2H5=>C2H4Z+R2OH+CO2 4.50E+11 0 25000 324 R1H+R1H+M=H2+M 1.87E+18 # 0 291 .COOOC3H7=>C3H6Y+R2OH+CO2 4.50E+11 0 25000 325 B4CH+R1H=B3C+H2 7.80E+13 0 0 292 C2H6CO+R1H=>H2+CH2COZ+R4CH3 2.70E+07 2 5000 326 B6CH2+M=B5CH2+M 1.51E+13 0 0 293 C2H6CO+R2OH=>H2O+CH2COZ+R4CH3 7.80E+06 2 -765 327 B6CH2+R1H=B4CH+H2 3.00E+13 0 0 294 C2H6CO+R3OOH=>H2O2+CH2COZ+R4CH3 1.20E+12 0 15500 328 B5CH2+R1H=B4CH+H2 6.00E+12 0 -1800 295 C2H6CO+R4CH3=>CH4+CH2COZ+R4CH3 6.00E+11 0 9600 329 B5CH2+B3C=R9C2HT+R1H 5.00E+13 0 0296 C2H6CO+R8CH3OO=>CH3OOH+CH2COZ+R4CH3 6.00E+11 0 9600 330 B5CH2+B5CH2=>C2H2T+R1H+R1H 1.20E+14 0 800 297 C2H6CO+R11C2H5=>C2H6+CH2COZ+R4CH3 6.00E+11 0 11000 331 R4CH3+M=B5CH2+R1H+M 2.91E+16 0 90700 298 C3H8CO+R1H=>H2+CH2COZ+R11C2H5 2.70E+07 2 5000 332 R4CH3+R1H=B6CH2+H2 6.00E+13 0 15000 299 C3H8CO+R2OH=>H2O+CH2COZ+R11C2H5 7.80E+06 2 -765 333 R4CH3+B4CH=R10C2H3V+R1H 3.00E+13 0 0 300 C3H8CO+R3OOH=>H2O2+CH2COZ+R11C2H5 1.20E+12 0 15500 334 R4CH3+B6CH2=C2H4Z+R1H 1.80E+13 0 0 301 C3H8CO+R4CH3=>CH4+CH2COZ+R11C2H5 6.00E+11 0 9600 335 R4CH3+B5CH2=C2H4Z+R1H 4.20E+13 0 0 302 C3H8CO+R8CH3OO=>CH3OOH+CH2COZ+R11C2H5 6.00E+11 0 9600 336 R4CH3+B3C=C2H2T+R1H 5.00E+13 0 0 303 C3H8CO+R11C2H5=>C2H6+CH2COZ+R11C2H5 6.00E+11 0 11000 337 R4CH3+R4CH3(+M)=>C2H6(+M) 3.61E+13 0 0 304 C4H6Z2+C2H4Z=>C6H10Z#6 3.00E+10 0 27500 338 C2H6(+M)=>R4CH3+R4CH3(+M) 1.80E+21 # 90900 305 .C3H5Y+R1H=>C3H6Y 1.00E+13 0 0 339 R4CH3+R4CH3=R11C2H5+R1H 3.00E+13 0 13500 306 .C3H5Y+R2OH=>C3H5OHY 1.00E+13 0 0 340 R4CH3+R4CH3=C2H4Z+H2 2.10E+14 0 19300

269

Rex No Reaction A b Ea

Rex No Reaction A b Ea

341 R1H+R4CH3(+M)=>CH4(+M) 1.67E+14 0 0 375 C2H6+B6CH2=R4CH3+R11C2H5 1.10E+14 0 0 342 CH4(+M)=>R4CH3+R1H(+M) 2.40E+16 0 105000 376 C2H6+R4CH3=R11C2H5+CH4 1.50E-07 6 5800 343 CH4(+CH4)=>R4CH3+R1H(+CH4) 2.40E+16 0 105000 377 C2H6+R9C2HT=C2H2T+R11C2H5 3.60E+12 0 0 344 CH4+R1H=R4CH3+H2 1.30E+04 3 8000 378 C2H6+R10C2H3V=R11C2H5+C2H4Z 6.00E+02 3 10500 345 CH4+B4CH=C2H4Z+R1H 3.00E+13 0 -400 379 B1O+H2=R2OH+R1H 5.10E+04 3 6200 346 CH4+B6CH2=R4CH3+R4CH3 4.20E+13 0 0 380 B1O+B4CH=B2CO+R1H 3.90E+13 0 0 347 R9C2HT+B6CH2=C2H2T+B4CH 1.80E+13 0 0 381 B1O+B4CH=B3C+R2OH 1.50E+13 0 4700 348 R9C2HT+B5CH2=C2H2T+B4CH 1.80E+13 0 0 382 B1O+B6CH2=>B2CO+2R1H 1.50E+13 0 0 349 R9C2HT+CH4=C2H2T+R4CH3 1.20E+12 0 0 383 B1O+B6CH2=B2CO+H2 1.50E+13 0 0 350 C2H2T+M=R9C2HT+R1H+M 1.14E+17 0 107000 384 B1O+B5CH2=>B2CO+2R1H 7.20E+13 0 0 351 C2H2T+R1H=R9C2HT+H2 6.60E+13 0 27700 385 B1O+B5CH2=B2CO+H2 4.80E+13 0 0 352 R10C2H3V(+M)=C2H2T+R1H(+M) 2.00E+14 0 39800 386 B1O+R4CH3=HCHO+R1H 8.40E+13 0 0 353 R10C2H3V+R1H=C2H2T+H2 1.20E+13 0 0 387 B1O+R4CH3=R7CH3O 8.00E+15 # 600 354 R10C2H3V+B6CH2=C2H2T+R4CH3 1.80E+13 0 0 388 B1O+CH4=R4CH3+R2OH 7.20E+08 2 8400 355 R10C2H3V+B5CH2=C2H2T+R4CH3 1.80E+13 0 0 389 B1O+R9C2HT=B4CH+B2CO 1.00E+13 0 0 356 R10C2H3V+R4CH3=CH4+C2H2T 3.90E+11 0 0 390 B1O+C2H2T=B5CH2+B2CO 2.17E+06 2 1600 357 R10C2H3V+R9C2HT=2C2H2T 9.60E+11 0 0 391 B1O+C2H2T=R12CHCOV+R1H 5.06E+06 2 1600 358 R10C2H3V+R10C2H3V=C2H4Z+C2H2T 9.60E+11 0 0 392 B1O+R10C2H3V=R4CH3+B2CO 3.00E+13 0 0 359 C2H4Z+M=C2H2T+H2+M 9.97E+16 0 71600 393 B1O+R10C2H3V=CH2COZ+R1H 9.60E+13 0 0 360 C2H4Z+M=R10C2H3V+R1H+M 7.40E+17 0 96700 394 B1O+C2H4Z=R4CH3+R5CHO 8.10E+06 2 200 361 C2H4Z+R1H=R10C2H3V+H2 5.00E+07 1.9 13000 395 B1O+C2H4Z=HCHO+B5CH2 4.00E+05 2 200 362 C2H4Z+R4CH3=CH4+R10C2H3V 6.30E+11 0 16000 396 B1O+C2H4Z=CH2COZ+H2 6.60E+05 2 200 363 R11C2H5(+M)=C2H4Z+R1H(+M) 8.20E+13 0 40000 397 B1O+C2H4Z=R13CH2CHO+R1H 4.70E+06 2 200364 R11C2H5+R1H=C2H4Z+H2 1.80E+12 0 0 398 B1O+C2H4Z=R2OH+R10C2H3V 1.50E+07 2 3700 365 R11C2H5+R1H=C2H6 3.60E+13 0 0 399 B1O+R11C2H5=HCHO+R4CH3 1.10E+13 0 0 366 R11C2H5+B6CH2=C2H4Z+R4CH3 9.00E+12 0 0 400 B1O+R11C2H5=CH3CHO+R1H 5.50E+13 0 0 367 R11C2H5+B5CH2=C2H4Z+R4CH3 1.80E+13 0 0 401 B1O+R11C2H5=C2H4Z+R2OH 3.00E+13 0 0 368 R11C2H5+R4CH3=C2H4Z+CH4 1.10E+12 0 0 402 B1O+C2H6=R11C2H5+R2OH 1.00E+09 2 5800 369 R11C2H5+R9C2HT=C2H2T+C2H4Z 1.80E+12 0 0 403 R1H+B1O+M=R2OH+M 1.18E+19 # 0 370 R11C2H5+R10C2H3V=2C2H4Z 4.80E+11 0 0 404 R1H+R2OH+M=H2O+M 5.53E+22 # 0 371 R11C2H5+R10C2H3V=C2H2T+C2H6 4.80E+11 0 0 405 R2OH+H2=R1H+H2O 1.00E+08 2 3300 372 R11C2H5+R11C2H5=C2H4Z+C2H6 1.40E+12 0 0 406 R2OH+B3C=B2CO+R1H 5.00E+13 0 0 373 C2H6+M=C2H4Z+H2+M 2.30E+17 0 67400 407 R2OH+B4CH=R5CHO+R1H 3.00E+13 0 0 374 C2H6+R1H=R11C2H5+H2 1.40E+09 1.5 7400 408 R2OH+B6CH2=HCHO+R1H 3.00E+13 0 0

270

Rex No Reaction A b Ea

Rex No Reaction A b Ea

409 R2OH+B5CH2=HCHO+R1H 1.80E+13 0 0 443 R5CHO+R10C2H3V=C2H4Z+B2CO 9.00E+13 0 0 410 R2OH+R4CH3=B6CH2+H2O 7.20E+13 0 2700 444 R10C2H3V+HCHO=R5CHO+C2H4Z 5.40E+03 3 5900 411 R2OH+R4CH3(+M)=CH3OH(+M) 6.00E+13 0 0 445 R5CHO+R11C2H5=C2H6+B2CO 1.20E+14 0 0 412 R2OH+R4CH3=HCHO+H2 3.20E+12 -0.5 10800 446 R11C2H5+HCHO=R5CHO+C2H6 5.57E+03 3 5860 413 R2OH+R4CH3=R7CH3O+R1H 5.70E+12 -0.2 13900 447 R5CHO+B1O=R1H+CO2 3.00E+13 0 0 414 R2OH+CH4=R4CH3+H2O 1.60E+07 1.8 2700 448 R5CHO+B1O=R2OH+B2CO 3.00E+13 0 0 415 R2OH+R9C2HT=C2H2T+B1O 1.80E+13 0 0 449 R5CHO+R2OH=H2O+B2CO 1.10E+14 0 0 416 R2OH+R9C2HT=B5CH2+B2CO 1.80E+13 0 0 450 R5CHO+R5CHO=HCHO+B2CO 3.00E+13 0 0 417 R2OH+R9C2HT=R12CHCOV+R1H 2.00E+13 0 0 451 HCHO+M=R5CHO+R1H+M 1.40E+36 # 96800 418 R2OH+C2H2T=R9C2HT+H2O 1.40E+04 2.7 12000 452 HCHO+M=H2+B2CO+M 3.26E+36 # 96800 419 R2OH+C2H2T=CH2COZ+R1H 2.20E-04 4.5 -1000 453 HCHO+R1H=R5CHO+H2 1.30E+08 2 2100 420 R2OH+C2H2T=R4CH3+B2CO 4.80E-04 4 -2000 454 HCHO+B4CH=R13CH2CHO 9.60E+13 0 -500 421 R2OH+R10C2H3V=C2H2T+H2O 3.00E+13 0 0 455 HCHO+B6CH2=R4CH3+R5CHO 1.20E+12 0 0 422 R2OH+R10C2H3V=CH3CHO 3.00E+13 0 0 456 HCHO+B1O=R5CHO+R2OH 4.10E+11 1 2700 423 R2OH+C2H4Z=R10C2H3V+H2O 2.00E+13 0 5900 457 HCHO+R2OH=R5CHO+H2O 3.40E+09 1 -400 424 R2OH+C2H4Z=R4CH3+HCHO 2.00E+12 0 900 458 R7CH3O+M=HCHO+R1H+M 1.55E+14 0 13500 425 R2OH+R11C2H5=C2H4Z+H2O 2.40E+13 0 0 459 R7CH3O+R1H=HCHO+H2 1.80E+13 0 0 426 R2OH+R11C2H5=>R4CH3+R1H+HCHO 2.40E+13 0 0 460 R7CH3O+B6CH2=R4CH3+HCHO 1.80E+13 0 0 427 R2OH+C2H6=R11C2H5+H2O 7.20E+06 2 900 461 R7CH3O+B5CH2=R4CH3+HCHO 1.80E+13 0 0 428 R2OH+R2OH=H2O+B1O 1.50E+09 1.1 100 462 R7CH3O+R4CH3=HCHO+CH4 2.40E+13 0 0 429 H2O+B4CH=R6CH2OH 5.70E+12 0 -800 463 R7CH3O+CH4=R4CH3+CH3OH 1.60E+11 0 8800 430 H2O+B6CH2=CH3OH 1.80E+13 0 0 464 R7CH3O+R9C2HT=HCHO+C2H2T 2.40E+13 0 0 431 B2CO+R4CH3(+M)=R14CH3CO(+M) 5.00E+11 0 6900 465 R7CH3O+R10C2H3V=HCHO+C2H4Z 2.40E+13 0 0432 B2CO+B1O+M=CO2+M 1.54E+15 0 3000 466 R7CH3O+C2H4Z=HCHO+R11C2H5 1.20E+11 0 6700 433 B2CO+R2OH=CO2+R1H 6.30E+06 1.5 -500 467 R7CH3O+R11C2H5=HCHO+C2H6 2.40E+13 0 0 434 R5CHO+M=R1H+B2CO+M 1.90E+17 -1 17000 468 R7CH3O+C2H6=R11C2H5+CH3OH 2.40E+11 0 7000 435 R5CHO+R1H=H2+B2CO 9.00E+13 0 0 469 R7CH3O+B1O=HCHO+R2OH 1.80E+12 0 0 436 R5CHO+R1H=B1O+B5CH2 4.00E+13 0 102500 470 R7CH3O+R2OH=HCHO+H2O 1.80E+13 0 0 437 R5CHO+B6CH2=R4CH3+B2CO 1.80E+13 0 0 471 R7CH3O+B2CO=R4CH3+CO2 1.60E+13 0 11700 438 R5CHO+B5CH2=R4CH3+B2CO 1.80E+13 0 0 472 R7CH3O+R5CHO=CH3OH+B2CO 9.10E+13 0 0 439 R5CHO+R4CH3=CH4+B2CO 1.20E+14 0 0 473 R7CH3O+HCHO=CH3OH+R5CHO 1.00E+11 0 3000 440 R5CHO+R4CH3=CH3CHO 1.80E+13 0 0 474 R7CH3O+R7CH3O=CH3OH+HCHO 6.00E+13 0 0 441 R4CH3+HCHO=R5CHO+CH4 7.70E-08 6.1 1970 475 R6CH2OH+M=HCHO+R1H+M 1.26E+16 0 30000 442 R5CHO+R9C2HT=C2H2T+B2CO 6.00E+13 0 0 476 R6CH2OH+R1H=R4CH3+R2OH 9.60E+13 0 0

271

Rex No Reaction A b Ea

Rex No Reaction A b Ea

477 R6CH2OH+R1H=HCHO+H2 6.00E+12 0 0 511 CH3OH+R7CH3O=CH3OH+R6CH2OH 3.00E+11 0 4100 478 R6CH2OH+H2=CH3OH+R1H 6.70E+05 2 13400 512 R12CHCOV+M=B4CH+B2CO+M 6.00E+15 0 58800 479 R6CH2OH+B6CH2=CH3CHO+R1H 1.80E+13 0 0 513 R12CHCOV+R1H=B5CH2+B2CO 1.50E+14 0 0 480 R6CH2OH+B5CH2=C2H4Z+R2OH 2.40E+13 0 0 514 R12CHCOV+R1H=B6CH2+B2CO 1.30E+14 0 0 481 R6CH2OH+B5CH2=R4CH3+HCHO 1.20E+12 0 0 515 R12CHCOV+B5CH2=R9C2HT+HCHO 1.00E+13 0 2000 482 R6CH2OH+R4CH3=C2H5OH 1.20E+13 0 0 516 R12CHCOV+B5CH2=R10C2H3V+B2CO 3.00E+13 0 0 483 R6CH2OH+R4CH3=CH4+HCHO 2.40E+12 0 0 517 R12CHCOV+B1O=>B2CO+B2CO+R1H 9.60E+13 0 0 484 R6CH2OH+CH4=CH3OH+R4CH3 2.17E+01 3.1 16200 518 R12CHCOV+R2OH=>R5CHO+B2CO+R1H 1.00E+13 0 0 485 R6CH2OH+R9C2HT=C2H2T+HCHO 4.80E+13 0 0 519 CH2COZ+M=B6CH2+B2CO+M 6.57E+15 0 57600 486 R6CH2OH+C2H2T=R10C2H3V+HCHO 7.20E+11 0 9000 520 CH2COZ+M=R12CHCOV+R1H+M 2.70E+17 0 87000 487 R6CH2OH+R10C2H3V=C2H4Z+HCHO 4.20E+13 0 0 521 CH2COZ+R1H=R4CH3+B2CO 1.80E+13 0 3400 488 R6CH2OH+R11C2H5=C2H4Z+CH3OH 2.40E+12 0 0 522 CH2COZ+R1H=R12CHCOV+H2 5.00E+13 0 8000 489 R6CH2OH+R11C2H5=C2H6+HCHO 2.40E+12 0 0 523 CH2COZ+B5CH2=C2H4Z+B2CO 1.30E+14 0 0 490 R6CH2OH+C2H6=CH3OH+R11C2H5 1.99E+02 3 14000 524 CH2COZ+B1O=B5CH2+CO2 1.80E+12 0 1300 491 R6CH2OH+B1O=HCHO+R2OH 4.20E+13 0 0 525 CH2COZ+B1O=R12CHCOV+R2OH 1.00E+13 0 8000 492 R6CH2OH+R2OH=H2O+HCHO 2.40E+13 0 0 526 CH2COZ+R2OH=R12CHCOV+H2O 7.50E+12 0 2000 493 R6CH2OH+R5CHO=CH3OH+B2CO 1.20E+14 0 0 527 CH2COZ+R2OH=R4CH3+CO2 2.52E+12 0 0 494 R6CH2OH+R5CHO=HCHO+HCHO 1.80E+14 0 0 528 CH2COZ+R2OH=R6CH2OH+B2CO 4.68E+12 0 0 495 R6CH2OH+HCHO=CH3OH+R5CHO 5.50E+03 2.8 5900 529 R14CH3CO+R1H=R4CH3+R5CHO 9.60E+13 0 0 496 R6CH2OH+R7CH3O=CH3OH+HCHO 2.40E+13 0 0 530 R14CH3CO+B6CH2=R4CH3+CH2COZ 1.80E+13 0 0 497 R6CH2OH+R6CH2OH=CH3OH+HCHO 1.40E+13 0 0 531 R14CH3CO+B5CH2=R4CH3+CH2COZ 1.80E+13 0 0 498 CH3OH+R1H=R4CH3+H2O 2.00E+14 0 5300 532 R14CH3CO+B1O=R4CH3+CO2 9.60E+12 0 0 499 CH3OH+R1H=R7CH3O+H2 4.20E+06 2.1 4900 533 R14CH3CO+R2OH=CH2COZ+H2O 1.20E+13 0 0 500 CH3OH+B6CH2=R6CH2OH+R4CH3 1.50E+12 0 0 534 R14CH3CO+R2OH=>R4CH3+B2CO+R2OH 3.00E+13 0 0 501 CH3OH+B5CH2=R4CH3+R6CH2OH 3.19E+01 3.2 7200 535 R14CH3CO+R5CHO=CH3CHO+B2CO 9.00E+12 0 0 502 CH3OH+B5CH2=R4CH3+R7CH3O 1.44E+01 3.1 6900 536 R14CH3CO+HCHO=CH3CHO+R5CHO 1.80E+11 0 12900 503 CH3OH+R9C2HT=C2H2T+R6CH2OH 6.00E+12 0 0 537 R14CH3CO+R7CH3O=CH3OH+CH2COZ 6.00E+12 0 0 504 CH3OH+R9C2HT=C2H2T+R7CH3O 1.20E+12 0 0 538 R14CH3CO+R7CH3O=HCHO+CH3CHO 6.00E+12 0 0 505 CH3OH+R10C2H3V=C2H4Z+R6CH2OH 3.19E+01 3.2 7200 539 R14CH3CO+CH3OH=CH3CHO+R6CH2OH 4.85E+03 3 12300 506 CH3OH+R10C2H3V=C2H4Z+R7CH3O 1.44E+01 3.1 6900 540 R14CH3CO+R14CH3CO=CH2COZ+CH3CHO 1.20E+13 0 0 507 CH3OH+B1O=R6CH2OH+R2OH 3.40E+13 0 5500 541 R13CH2CHO=R14CH3CO 1.00E+13 0 47000 508 CH3OH+B1O=R7CH3O+R2OH 1.00E+13 0 4700 542 R13CH2CHO=R1H+CH2COZ 1.60E+13 0 35000 509 CH3OH+R2OH=R6CH2OH+H2O 3.10E+06 2 -340 543 CH3CHO+R1H=H2+R14CH3CO 4.00E+13 0 4200 510 CH3OH+R2OH=R7CH3O+H2O 5.40E+05 2 -340 544 CH3CHO+R4CH3=R14CH3CO+CH4 2.00E-06 6 2500

272

Rex No Reaction A b Ea

Rex No Reaction A b Ea

545 CH3CHO+R10C2H3V=C2H4Z+R14CH3CO 8.10E+10 0 3700 579 C2H5OH+R4CH3=CH4+R15C2H5O 1.40E+02 3 7650 546 CH3CHO+R11C2H5=C2H6+R14CH3CO 1.30E+12 0 8500 580 C2H5OH+R1H=H2+R2OH+C2H4Z 1.20E+07 2 5100 547 CH3CHO+B1O=R14CH3CO+R2OH 1.40E+13 0 2300 581 C2H5OH+B1O=R2OH+R2OH+C2H4Z 9.40E+07 2 5460 548 CH3CHO+R2OH=R14CH3CO+H2O 4.20E+12 0 500 582 C2H5OH+R2OH=H2O+R2OH+C2H4Z 1.70E+11 0 600 549 CH3CHO+R7CH3O=R14CH3CO+CH3OH 2.40E+11 0 1800 583 C2H5OH+R3OOH=H2O2+R2OH+C2H4Z 1.20E+04 3 15700 550 CH3CHO+R13CH2CHO=CH3CHO+R14CH3CO 2.50E+07 0 0 584 C2H5OH+R4CH3=CH4+R2OH+C2H4Z 2.20E+02 3 9600 551 C2H4O#3=CH4+B2CO 1.20E+13 0 57200 585 C2H5OH+R1H=H2+CH3CHO+R1H 2.60E+07 2 2800 552 C2H4O#3=CH3CHO 7.30E+13 0 57200 586 C2H5OH+B1O=R2OH+CH3CHO+R1H 1.90E+07 2 1820 553 C2H4O#3=R4CH3+R5CHO 3.60E+13 0 57200 587 C2H5OH+R2OH=H2O+CH3CHO+R1H 4.60E+11 0 0 554 C2H4O#3+R1H=H2+R13CH2CHO 2.00E+13 0 8300 588 C2H5OH+R3OOH=H2O2+CH3CHO+R1H 8.20E+03 3 10700 555 C2H4O#3+R1H=H2O+R10C2H3V 5.00E+09 0 5000 589 C2H5OH+R4CH3=CH4+CH3CHO+R1H 7.30E+02 3 7900 556 C2H4O#3+R1H=C2H4Z+R2OH 9.50E+10 0 5000 590 B1O+B1O+M=O2+M 5.40E+13 0 -1790 557 C2H4O#3+R4CH3=CH4+R13CH2CHO 1.10E+12 0 11800 591 O2+R1H=R2OH+B1O 9.80E+13 0 14800 558 C2H4O#3+R4CH3=R11C2H5+HCHO 1.40E+11 0 7600 592 O2+R1H(+M)=R3OOH(+M) 4.52E+13 0 0 559 C2H4O#3+R4CH3=C2H4Z+R7CH3O 1.50E+10 0 7600 593 O2+R1H(+H2O)=R3OOH(+H2O) 4.52E+13 0 0 560 C2H4O#3+R9C2HT=C2H2T+R13CH2CHO 1.20E+12 0 9800 594 O2+B3C=B2CO+B1O 1.20E+14 0 0 561 C2H4O#3+R10C2H3V=C2H4Z+R13CH2CHO 2.00E+12 0 9300 595 O2+B4CH=R5CHO+B1O 3.30E+13 0 0 562 C2H4O#3+R11C2H5=C2H6+R13CH2CHO 6.80E+11 0 11400 596 O2+B4CH=B2CO+R2OH 3.20E+13 0 0 563 C2H4O#3+B1O=R2OH+R13CH2CHO 1.90E+12 0 5200 597 O2+B6CH2=>B2CO+R2OH+R1H 3.10E+12 0 0 564 C2H4O#3+R2OH=H2O+R13CH2CHO 1.80E+13 0 3600 598 O2+B5CH2=R5CHO+R2OH 4.30E+10 0 -500 565 C2H4O#3+R5CHO=HCHO+R13CH2CHO 3.70E+12 0 15800 599 O2+B5CH2=CO2+H2 6.90E+11 0 500 566 C2H4O#3+R7CH3O=CH3OH+R13CH2CHO 1.30E+12 0 5800 600 O2+B5CH2=>CO2+R1H+R1H 1.60E+12 0 1000 567 C2H4O#3+R6CH2OH=CH3OH+R13CH2CHO 8.40E+11 0 13400 601 O2+B5CH2=B2CO+H2O 1.90E+10 0 -1000568 C2H4O#3+R14CH3CO=CH3CHO+R13CH2CHO 4.00E+12 0 17500 602 O2+B5CH2=>B2CO+R2OH+R1H 8.60E+10 0 -500 569 C2H4O#3+R13CH2CHO=CH3CHO+R13CH2CHO 6.80E+11 0 15400 603 O2+B5CH2=HCHO+B1O 1.00E+14 0 4500 570 R15C2H5O=HCHO+R4CH3 8.00E+13 0 21500 604 O2+R4CH3(+M)=R8CH3OO(+M) 7.80E+08 1 0 571 R15C2H5O=CH3CHO+R1H 2.00E+14 0 23300 605 O2+R4CH3=R7CH3O+B1O 1.30E+14 0 31300 572 C2H5OH(+M)=R11C2H5+R2OH(+M) 1.20E+23 -1.5 96000 606 O2+R4CH3=HCHO+R2OH 3.00E+30 # 36600 573 C2H5OH(+M)=C2H4Z+H2O(+M) 2.80E+13 0.1 66100 607 O2+CH4=R4CH3+R3OOH 4.00E+13 0 56700 574 C2H5OH(+M)=CH3CHO+H2(+M) 7.20E+11 0.1 91000 608 O2+R9C2HT=B2CO+R5CHO 3.80E+13 # 0 575 C2H5OH+R1H=H2+R15C2H5O 1.50E+07 1.6 3040 609 O2+R9C2HT=R12CHCOV+B1O 9.00E+12 # 0 576 C2H5OH+B1O=R2OH+R15C2H5O 1.60E+07 2 4450 610 O2+C2H2T=R9C2HT+R3OOH 1.20E+13 0 74500 577 C2H5OH+R2OH=H2O+R15C2H5O 7.50E+11 0.3 1600 611 O2+C2H2T=R5CHO+R5CHO 7.00E+07 2 30600 578 C2H5OH+R3OOH=H2O2+R15C2H5O 2.50E+12 0 24000 612 O2+R10C2H3V=C2H2T+R3OOH 1.34E+06 2 -400

273

Rex No Reaction A b Ea

Rex No Reaction A b Ea

613 O2+R10C2H3V=HCHO+R5CHO 4.50E+16 -1.4 1000 647 R3OOH+C2H4Z=C2H4O#3+R2OH 2.20E+12 0 17200 614 O2+R10C2H3V=B1O+R13CH2CHO 3.30E+11 -0.3 10 648 R3OOH+R11C2H5=>R4CH3+HCHO+R2OH 2.40E+13 0 0 615 O2+C2H4Z=R10C2H3V+R3OOH 4.20E+13 0 57400 649 R3OOH+R11C2H5=C2H4Z+H2O2 3.00E+11 0 0 616 O2+R11C2H5=R17C2H5OO 2.20E+10 0.8 -600 650 R3OOH+C2H6=R11C2H5+H2O2 1.30E+13 0 20400 617 O2+R11C2H5=C2H4Z+R3OOH 8.40E+11 0 3900 651 R3OOH+R2OH=H2O+O2 2.90E+13 0 -500 618 O2+R11C2H5=R15C2H5O+B1O 1.20E+13 -0.2 27900 652 R3OOH+B2CO=CO2+R2OH 1.50E+14 0 23600 619 O2+R11C2H5=CH3CHO+R2OH 6.00E+10 0 6900 653 R3OOH+R5CHO=>R2OH+R1H+CO2 3.00E+13 0 0 620 O2+C2H6=R11C2H5+R3OOH 6.00E+13 0 51700 654 R3OOH+HCHO=R5CHO+H2O2 3.00E+12 0 13000 621 O2+R2OH=R3OOH+B1O 2.20E+13 0 52500 655 R3OOH+R7CH3O=HCHO+H2O2 3.00E+11 0 0 622 O2+B2CO=CO2+B1O 2.50E+12 0 47700 656 R3OOH+R6CH2OH=HCHO+H2O2 1.20E+13 0 0 623 O2+R5CHO=B2CO+R3OOH 7.60E+12 0 410 657 R3OOH+CH3OH=R6CH2OH+H2O2 9.60E+10 0 12600 624 O2+HCHO=R5CHO+R3OOH 2.00E+13 0 38800 658 R3OOH+R14CH3CO=>R4CH3+CO2+R2OH 3.00E+13 0 0 625 O2+R7CH3O=HCHO+R3OOH 2.20E+10 0 1700 659 R3OOH+CH3CHO=R14CH3CO+H2O2 1.00E+12 0 10000 626 O2+R6CH2OH=HCHO+R3OOH 1.20E+12 0 0 660 R3OOH+C2H4O#3=H2O2+R13CH2CHO 1.60E+12 0 15000 627 O2+CH3OH=R6CH2OH+R3OOH 2.00E+13 0 44900 661 R3OOH+R3OOH=H2O2+O2 1.30E+11 0 -1630 628 O2+R12CHCOV=>B2CO+B2CO+R2OH 1.50E+12 0 2500 662 R3OOH+R3OOH=H2O2+O2 4.20E+14 0 11980 629 O2+R14CH3CO=R18CH3COOO 2.40E+12 0 0 663 R2OH+R2OH(+M)=>H2O2(+M) 7.23E+13 # 0 630 O2+R13CH2CHO=>HCHO+R2OH+B2CO 5.90E+09 0 -1400 664 H2O2(+M)=>R2OH+R2OH(+M) 3.00E+14 0 48500 631 O2+R13CH2CHO=CH2COZ+R3OOH 1.00E+10 0 -1400 665 H2O2+R1H=H2+R3OOH 1.70E+12 0 3700 632 O2+CH3CHO=R14CH3CO+R3OOH 5.00E+13 0 36400 666 H2O2+R1H=H2O+R2OH 1.00E+13 0 3600 633 O2+CH3CHO=R13CH2CHO+R3OOH 1.00E+13 0.5 46000 667 H2O2+B6CH2=R7CH3O+R2OH 3.00E+13 0 0 634 O2+C2H4O#3=R3OOH+R13CH2CHO 5.00E+13 0 48000 668 H2O2+R10C2H3V=C2H4Z+R3OOH 1.20E+10 0 -600 635 O2+R15C2H5O=CH3CHO+R3OOH 6.00E+10 0 1700 669 H2O2+B1O=R2OH+R3OOH 6.60E+11 0 4000636 R3OOH+R1H=H2+O2 4.30E+13 0 1400 670 H2O2+R2OH=H2O+R3OOH 7.80E+12 0 1300 637 R3OOH+R1H=2R2OH 1.70E+14 0 900 671 CO2+B5CH2=HCHO+B2CO 2.30E+10 0 0 638 R3OOH+R1H=H2O+B1O 3.00E+13 0 1700 672 R8CH3OO=HCHO+R2OH 1.50E+13 0 47000 639 R3OOH+B6CH2=HCHO+R2OH 3.00E+13 0 0 673 R8CH3OO+R1H=R7CH3O+R2OH 9.60E+13 0 0 640 R3OOH+B5CH2=HCHO+R2OH 1.80E+13 0 0 674 R8CH3OO+H2=CH3OOH+R1H 3.00E+13 0 26000 641 R3OOH+R4CH3=R7CH3O+R2OH 1.80E+13 0 0 675 R8CH3OO+B6CH2=HCHO+R7CH3O 1.80E+13 0 0 642 R3OOH+CH4=R4CH3+H2O2 9.00E+12 0 24600 676 R8CH3OO+B5CH2=HCHO+R7CH3O 1.80E+13 0 0 643 R3OOH+R9C2HT=R12CHCOV+R2OH 1.80E+13 0 0 677 R8CH3OO+R4CH3=R7CH3O+R7CH3O 5.00E+12 0 -1400 644 R3OOH+C2H2T=CH2COZ+R2OH 6.00E+09 0 8000 678 R8CH3OO+CH4=CH3OOH+R4CH3 1.80E+11 0 18500 645 R3OOH+R10C2H3V=>R2OH+R4CH3+B2CO 3.00E+13 0 0 679 R8CH3OO+R9C2HT=R7CH3O+R12CHCOV 2.40E+13 0 0 646 R3OOH+C2H4Z=CH3CHO+R2OH 6.00E+09 0 7900 680 R8CH3OO+C2H2T=CH3OOH+R9C2HT 5.60E+11 0 24500

274

Rex No Reaction A b Ea

Rex No Reaction A b Ea

681 R8CH3OO+R10C2H3V=R7CH3O+R13CH2CHO 2.40E+13 0 0 715 R17C2H5OO+C2H4Z=C2H5OOH+R10C2H3V 3.90E+12 0 24400 682 R8CH3OO+C2H4Z=R7CH3O+C2H4O#3 1.10E+15 0 20000 716 R17C2H5OO+C2H4Z=R15C2H5O+C2H4O#3 2.30E+16 0 21900 683 R8CH3OO+C2H4Z=CH3OOH+R10C2H3V 3.90E+12 0 24500 717 R17C2H5OO+C2H6=C2H5OOH+R11C2H5 5.10E+12 0 19500 684 R8CH3OO+R11C2H5=R7CH3O+R15C2H5O 2.40E+13 0 0 718 R17C2H5OO+H2O=C2H5OOH+R2OH 5.60E+12 0 30600 685 R8CH3OO+C2H6=CH3OOH+R11C2H5 2.90E+11 0 14900 719 R17C2H5OO+B2CO=CO2+R15C2H5O 1.00E+14 0 24000 686 R8CH3OO+B1O=R7CH3O+O2 3.60E+13 0 0 720 R17C2H5OO+HCHO=C2H5OOH+R5CHO 4.50E+12 0 14400 687 R8CH3OO+R2OH=CH3OH+O2 6.00E+13 0 0 721 R17C2H5OO+CH3OH=C2H5OOH+R7CH3O 2.80E+11 0 18400 688 R8CH3OO+R2OH=R7CH3O+R3OOH 3.00E+12 0 0 722 R17C2H5OO+CH3OH=C2H5OOH+R6CH2OH 2.80E+12 0 19500 689 R8CH3OO+B2CO=R7CH3O+CO2 1.00E+14 0 24000 723 R17C2H5OO+CH2COZ=C2H5OOH+R12CHCOV 1.70E+12 0 24400 690 R8CH3OO+R5CHO=>R7CH3O+R1H+CO2 3.00E+13 0 0 724 R17C2H5OO+CH3CHO=C2H5OOH+R14CH3CO 3.90E+12 0 14400 691 R8CH3OO+HCHO=CH3OOH+R5CHO 1.00E+12 0 12100 725 R17C2H5OO+CH3CHO=C2H5OOH+R13CH2CHO 1.70E+12 0 19500 692 R8CH3OO+R7CH3O=HCHO+CH3OOH 3.00E+11 0 0 726 R17C2H5OO+C2H4O#3=C2H5OOH+R13CH2CHO 2.20E+12 0 16300 693 R8CH3OO+R6CH2OH=>R7CH3O+R2OH+HCHO 1.20E+13 0 0 727 R17C2H5OO+R3OOH=O2+C2H5OOH 3.90E+11 0 -1300 694 R8CH3OO+CH3OH=CH3OOH+R6CH2OH 1.80E+12 0 13700 728 R17C2H5OO+H2O2=C2H5OOH+R3OOH 4.50E+11 0 10800 695 R8CH3OO+CH3OH=CH3OOH+R7CH3O 2.80E+11 0 18800 729 R17C2H5OO+R8CH3OO=>R15C2H5O+R7CH3O+O2 2.00E+11 0 0 696 R8CH3OO+CH2COZ=CH3OOH+R12CHCOV 1.70E+12 0 27000 730 R17C2H5OO+CH3OOH=C2H5OOH+R8CH3OO 1.10E+12 0 16300 697 R8CH3OO+R14CH3CO=R4CH3+CO2+R7CH3O 2.40E+13 0 0 731 R17C2H5OO+R17C2H5OO=2R15C2H5O+O2 4.10E+10 0 200 698 R8CH3OO+CH3CHO=CH3OOH+R14CH3CO 1.00E+12 0 12100 732 R17C2H5OO+R17C2H5OO=C2H5OH+CH3CHO+O2 1.80E+10 0 200 699 R8CH3OO+CH3CHO=CH3OOH+R13CH2CHO 1.70E+12 0 19200 733 R16C2H4OOH=C2H4O#3+R2OH 1.50E+11 0 20000 700 R8CH3OO+C2H4O#3=CH3OOH+R13CH2CHO 2.20E+12 0 16000 734 R16C2H4OOH=R6CH2OH+HCHO 2.50E+13 0 27500 701 R8CH3OO+R3OOH=CH3OOH+O2 2.50E+11 0 -1600 735 R16C2H4OOH=C2H4Z+R3OOH 2.00E+13 0 23500 702 R8CH3OO+R3OOH=>O2+HCHO+H2O 5.00E+10 0 0 736 C2H5OOH=R15C2H5O+R2OH 4.00E+15 0 42900 703 R8CH3OO+H2O2=CH3OOH+R3OOH 2.40E+12 0 9900 737 C2H5OOH+R1H=>CH3CHO+R2OH+H2 3.20E+13 0 7700 704 R8CH3OO+R8CH3OO=CH3OH+HCHO+O2 2.50E+10 0 -800 738 C2H5OOH+R4CH3=>CH3CHO+R2OH+CH4 5.70E+11 0 8700 705 R8CH3OO+R8CH3OO=R7CH3O+R7CH3O+O2 2.50E+10 0 -800 739 C2H5OOH+R9C2HT=>CH3CHO+R2OH+C2H2T 6.00E+11 0 9200 706 CH3OOH=R7CH3O+R2OH 6.00E+14 0 42300 740 C2H5OOH+R10C2H3V=>CH3CHO+R2OH+C2H4Z 1.00E+12 0 8700 707 CH3OOH+B1O=R8CH3OO+R2OH 2.00E+13 0 4800 741 C2H5OOH+R11C2H5=>CH3CHO+R2OH+C2H6 3.40E+11 0 11400 708 CH3OOH+R2OH=H2O+R8CH3OO 1.80E+12 0 -370 742 C2H5OOH+R2OH=>CH3CHO+R2OH+H2O 5.90E+12 0 900 709 CH3OOH+R7CH3O=>CH3OH+R2OH+HCHO 1.50E+11 0 6500 743 C2H5OOH+R5CHO=>CH3CHO+R2OH+HCHO 1.80E+12 0 16700 710 R17C2H5OO=R16C2H4OOH 4.20E+12 0 36900 744 C2H5OOH+R7CH3O=>CH3CHO+R2OH+CH3OH 6.30E+11 0 5500 711 R17C2H5OO+H2=C2H5OOH+R1H 7.90E+12 0 21000 745 C2H5OOH+R6CH2OH=>CH3CHO+R2OH+CH3OH 4.20E+11 0 13600 712 R17C2H5OO+R4CH3=R15C2H5O+R7CH3O 2.00E+12 0 -1200 746 C2H5OOH+R14CH3CO=>2CH3CHO+R2OH 2.00E+12 0 18500 713 R17C2H5OO+CH4=C2H5OOH+R4CH3 3.90E+12 0 24000 747 C2H5OOH+R13CH2CHO=>2CH3CHO+R2OH 3.40E+11 0 15700 714 R17C2H5OO+C2H2T=C2H5OOH+R9C2HT 5.60E+11 0 24400 748 C2H5OOH+R3OOH=>CH3CHO+R2OH+H2O2 8.00E+11 0 16200

275

Rex No Reaction A b Ea

Rex No Reaction A b Ea

749 C2H5OOH+R8CH3OO=>CH3CHO+R2OH+CH3OOH 1.10E+12 0 16700 783 CO2+N=NO+CO 1.90E+11 0 14.2 750 C2H5OOH+R17C2H5OO=>CH3CHO+R2OH+C2H5OOH 1.10E+12 0 16700 784 N2+CH=HCN+N 1.57E+12 0 75.1 751 R18CH3COOO+C2H4O#3=CH3COOOH+R13CH2CHO 1.00E+12 0 9300 785 N2+CH2=HCN+NH 1.00E+13 0 309.6 752 R18CH3COOO+R3OOH=CH3COOOH+O2 5.50E+10 0 -2600 786 NO+N2O=N2+NO2 1.00E+14 0 207.8 753 R18CH3COOO+C2H5OOH=CH3COOOH+R17C2H5OO 5.00E+11 0 9200 787 NO+N2H2=N2O+NH2 3.00E+12 0 0 754 R18CH3COOO+C2H5OOH=>CH3CHO+R2OH+CH3COOOH 5.00E+11 0 9200 788 NO+C=CN+O 1.93E+13 0 0 755 R18CH3COOO+R18CH3COOO=>2R4CH3+O2+2CO2 1.70E+12 0 -1000 789 NO+C=CO+N 2.89E+13 0 0 756 CH3COOOH=>R4CH3+CO2+R2OH 1.00E+16 0 40000 790 NO+H=>N+OH 2.17E+14 0 207.1 757 C2H4Z+R4CH3=>R19C3H7 2.10E+11 0 7350 791 N+OH=>NO+H 2.83E+13 0 0 758 R11C2H5+C2H4Z=>R20C4H9 1.10E+11 0 7300 792 NO+CH=CO+NH 1.20E+13 0 0 759 R11C2H5+R10C2H3V=>C4H8Y 1.50E+13 0 0 793 NO+CH=CN+OH 1.20E+13 0 0 760 R11C2H5+R11C2H5=>C4H10 1.10E+13 0 0 794 NO+CH=HCN+O 9.60E+13 0 0 761 R5CHO+R10C2H3V=>C2H3CHOZ 1.80E+13 0 0 795 NO+CH2=HOCN+H 1.39E+12 0 -4.6 762 R5CHO+R11C2H5=>C2H5CHO 1.80E+13 0 0 796 NO+CH2(S)=HCN+OH 9.64E+13 0 0 763 R6CH2OH+R11C2H5=C3H7OH 1.20E+13 0 0 797 NO+CH3=HCN+H2O 9.28E+11 0 69.9 764 R14CH3CO+R4CH3=>C2H6CO 4.00E+15 -0.8 0 798 NO+CH3=H2CN+OH 9.28E+11 0 69.9 765 R14CH3CO+R11C2H5=>C3H8CO 3.10E+14 -0.5 0 799 NO+HO2=NO2+OH 2.09E+12 0 -2 766 C2H3CHOZ+R2OH=B2CO+R10C2H3V+H2O 1.00E+13 0 0 800 NO+HO2=HNO+O2 2.00E+11 0 8.3 767 C2H3CHOZ+B1O=B2CO+R10C2H3V+R2OH 7.20E+12 0 2000 801 NO+HCCO=HOCN+CO 2.00E+13 0 0 768 C2H3CHOZ+B1O=CH2COZ+R5CHO+R1H 5.00E+07 1.8 80 802 NO+N=>N2+O 4.28E+13 0 6.6 769 C2H3CHOZ+R1H=B2CO+R10C2H3V+H2 4.00E+13 0 4200 803 N2+O=>NO+N 1.81E+14 0 318.4 770 C2H3CHOZ+R1H=C2H4Z+R5CHO 2.00E+13 0 3500 804 NO+NH=N2+OH 3.20E+13 0 53.2 771 C2H3CHOZ+O2=B2CO+R10C2H3V+R3OOH 3.00E+13 0 36000 805 NO+NH=N2O+H 4.16E+14 # 0 772 H2+CN=HCN+H 1.93E+04 2.9 6.8 806 NO+NH2=NNH+OH 2.41E+15 # 0 773 CH4+N=NH+CH3 1.00E+13 0 100.4 807 NO+NH2=N2+H2O 5.48E+15 # 0 774 CH4+CN=HCN+CH3 9.03E+04 2.6 -1.2 808 NO+NNH=N2+HNO 5.00E+13 0 0 775 O2+N=NO+O 9.03E+09 1 27.2 809 NO+HNO=N2O+OH 2.95E+05 0 0 776 O2+NH=HNO+O 3.91E+13 0 74.8 810 NO+NCO=N2O+CO 1.39E+18 # 3.2 777 O2+NH=NO+OH 7.59E+10 0 6.4 811 NO+M=N+O+M 3.62E+15 0 620.6 778 O2+NH2=HNO+OH 1.51E+12 -0.4 151 812 NO2+NO2=NO+NO+O2 2.00E+12 0 112.2 779 O2+NH2=H2NO+O 1.10E+18 -1.3 140.6 813 NO2+H=NO+OH 3.47E+14 0 6.2 780 O2+CN=NCO+O 7.23E+12 0 -1.7 814 NO2+O=NO+O2 1.00E+13 0 2.5 781 O2+NCO=NO+CO2 1.72E+07 0 -3.1 815 NO2+N=NO+NO 8.07E+11 0 0 782 CO+N2O=CO2+N2 9.77E+10 0 73 816 NO2+N=N2O+O 1.00E+12 0 0

276

Rex No Reaction A b Ea

Rex No Reaction A b Ea

817 NO2+NH=HNO+NO 1.00E+11 0.5 16.6 851 HCN+O=CN+OH 2.22E+05 2 25.6 818 NO2+NH=N2O+OH 9.71E+12 0 0 852 HCN+OH=CN+H2O 9.03E+12 0 44.9 819 NO2+NH2=N2O+H2O 2.03E+17 -1.7 0 853 HCN+OH=HOCN+H 5.85E+04 2 52.3 820 NO2+CN=NCO+NO 3.00E+13 0 0 854 HCN+OH=HNCO+H 1.98E-03 4 4.2 821 NO2+M=NO+O+M 3.13E+16 0 274.4 855 HCN+CN=C2N2+H 3.80E+07 2 0.4 822 N2O+C=CN+NO 5.12E+12 0 0 856 HOCN+H=H2O+CN 1.00E+12 0 0 823 N2O+H=N2+OH 4.37E+14 0 79 857 HOCN+H=H2+NCO 1.00E+12 0 0 824 N2O+O=N2+O2 1.00E+14 0 117.2 858 HOCN+H=HNCO+H 1.00E+13 0 0 825 N2O+O=NO+NO 6.92E+13 0 111.4 859 HNCO+H=NCO+H2 2.05E+14 # 84.7 826 N2O+OH=N2+HO2 6.31E+11 0 41.6 860 HNCO+H=NH2+CO 1.10E+14 0 53.2 827 N2O+N=N2+NO 1.00E+13 0 83.1 861 HNCO+O=NH+CO2 2.00E+13 0 54.5 828 N2O+NH=HNO+N2 2.00E+12 0 24.9 862 HNCO+O=HNO+CO 1.90E+12 0 43.1 829 N2O+CN=NCO+N2 1.00E+13 0 0 863 HNCO+O=OH+NCO 2.00E+14 0 96.4 830 N2O+M=N2+O+M 2.86E+15 0 251 864 HNCO+OH=NCO+H2O 1.99E+12 0 23.2 831 NH3+H=NH2+H2 5.42E+05 2.4 41.5 865 HNCO+OH=NH2+CO2 6.62E+11 0 23.2 832 NH3+O=>NH2+OH 9.64E+12 0 30.5 866 HNCO+HO2=NCO+H2O2 3.00E+13 0 121.3 833 NH3+OH=NH2+H2O 3.16E+12 0 8.4 867 HNCO+N=NH+NCO 3.98E+13 0 149.7 834 NH3+HO2=NH2+H2O2 2.51E+12 0 99.8 868 HNCO+NH=NH2+NCO 3.00E+13 0 99.2 835 NH3+NH2=N2H3+H2 7.94E+11 0.5 90.2 869 HNCO+NH2=NH3+NCO 1.00E+12 0 29.1 836 NH3(+M)=NH2+H(+M) 8.30E+15 0 458.7 870 HNCO+M=NH+CO+M 2.40E+16 0 354.5 837 NH3+M=NH+H2+M 1.80E+15 0 390.8 871 HNCO+M=H+NCO+M 2.86E+17 0 468.9 838 N2H2+H=NNH+H2 1.00E+13 0 4.2 872 H+NH=N+H2 1.02E+13 0 0 839 N2H2+O=NH2+NO 1.00E+13 0 0 873 H+NH2=NH+H2 6.02E+12 0 0840 N2H2+O=NNH+OH 1.00E+11 0.5 0 874 H+NNH=N2+H2 3.98E+13 0 12.5 841 N2H2+OH=NNH+H2O 1.00E+13 0 8.3 875 H+N2H3=NH2+NH2 1.58E+12 0 0 842 N2H2+NH=NNH+NH2 1.00E+13 0 4.2 876 H+N2H3=NH+NH3 1.00E+11 0 0 843 N2H2+NH2=NH+N2H3 1.00E+11 0.5 141.3 877 H+N2H3=N2H2+H2 1.00E+12 0 8.3 844 N2H2+NH2=NH3+NNH 1.00E+13 0 16.6 878 H+HNO=H2+NO 1.26E+13 0 16.6 845 N2H2+M=NNH+H+M 2.50E+16 0 207.8 879 H+NCO=NH+CO 5.24E+13 0 0 846 N2H2+M=NH+NH+M 7.91E+16 0 415.7 880 CH+N=CN+H 1.26E+13 0 0 847 C2N2+O=NCO+CN 1.29E+14 0 59.3 881 CH+NH=HCN+H 5.00E+13 0 0 848 C2N2+OH=HOCN+CN 1.87E+11 0 12 882 CH+NH2=HCN+H+H 3.00E+13 0 0 849 HCN+O=NCO+H 8.45E+05 2.1 25.6 883 CH2+N=HCN+H 5.00E+13 0 0 850 HCN+O=NH+CO 3.19E+05 2.1 25.6 884 CH2+NH=HCN+H+H 3.00E+13 0 0

277

Rex No Reaction A b Ea

Rex No Reaction A b Ea

885 CH3+N=H2CN+H 2.59E+14 0 3.5 910 N+NH=N2+H 6.31E+11 1 0886 C2H3+N=HCN+CH2 2.00E+13 0 0 911 N+NH2=N2+H+H 6.93E+13 0 0887 H2CCCH+N=HCN+C2H2 1.00E+13 0 0 912 N+NNH=NH+N2 3.16E+13 0 8.3888 O+NH=N+OH 3.72E+13 0 0 913 N+CN=>C+N2 1.81E+14 0 0889 O+NH=NO+H 5.50E+13 0 0 914 C+N2=>N+CN 5.24E+13 0 187.9890 O+NH2=NH+OH 6.90E+11 0.3 -0.8 915 N+H2CN=N2+CH2 2.00E+13 0 0891 O+NH2=HNO+H 8.93E+14 -0.5 1.4 916 N+NCO=NO+CN 2.77E+18 # 72.2892 O+NNH=N2+OH 1.00E+13 0 20.8 917 N+NCO=N2+CO 1.99E+13 0 0893 O+NNH=N2O+H 1.00E+13 0 12.5 918 NH+NH=N2+H+H 5.13E+13 0 0894 O+NNH=NH+NO 1.65E+14 -0.2 -4.2 919 NH+NH2=N2H2+H 1.51E+15 # 0895 O+HNO=OH+NO 5.01E+11 0.5 8.3 920 NH+NNH=N2+NH2 2.00E+11 1 8.3896 O+CN=CO+N 1.02E+13 0 0 921 NH+M=N+H+M 7.57E+14 0 315.9897 O+NCO=NO+CO 3.16E+13 0 0 922 NH2+NH2=N2H2+H2 3.98E+13 0 49.9898 OH+NH=HNO+H 1.00E+12 0.5 8.3 923 NH2+NH2=NH3+NH 5.00E+13 0 41.8899 OH+NH=N+H2O 5.01E+11 0.5 8.3 924 NH2+M=NH+H+M 7.91E+23 # 382.4900 OH+NH2=>O+NH3 1.99E+10 0.4 2.1 925 NH2+NNH=N2+NH3 1.00E+13 0 0901 OH+NH2=NH+H2O 5.01E+11 0.5 8.3 926 NH2+HNO=NH3+NO 5.01E+11 1 4.2902 OH+NNH=N2+H2O 3.16E+13 0 0 927 NNH=N2+H 3.00E+08 0 0903 OH+HNO=NO+H2O 1.08E+13 0 0 928 NNH+M=N2+H+M 2.50E+13 1 12.8904 OH+CN=NCO+H 6.02E+13 0 0 929 NNH+O2=N2+HO2 5.00E+12 0 0905 OH+NCO=NO+HCO 5.00E+12 0 62.8 930 N2H3+M=N2H2+H+M 2.50E+16 0 207.8906 OH+NCO=NO+CO+H 1.00E+13 0 0 931 N2H3+M=NH2+NH+M 2.50E+16 0 174.6907 HO2+NH2=HNO+H2O 1.57E+13 0 0 932 HNO+M=H+NO+M 5.09E+16 0 203.7908 HCCO+N=HCN+CO 5.00E+13 0 0 933 H2CN+M=HCN+H+M 7.50E+14 0 92909 N+N+M=N2+M 6.52E+15 0 0 934 NCO+M=N+CO+M 2.91E+15 0 195.4910 N+NH=N2+H 6.31E+11 0.5 0 935 H2O+CH=CH2O+H 5.72E+12 0 -3.2

278

Mechanism-II (High Temperature, above 1000 K) Rex No Reaction A b Ea

Rex No Reaction A b Ea

1 C3H8=>R4CH3+R11C2H5 9.40E+16 0 86903.5 36 R1H+R21C3H7=>C3H8 8.30E+12 0 0

2 C3H8+O2=>R3OOH+R21C3H7 1.40E+13 0 51776.7 37 R2OH+R21C3H7=>C3H7OH 5.90E+12 0 0

3 C3H8+O2=>R3OOH+R19C3H7 4.20E+13 0 54334.2 38 R3OOH+R21C3H7=>C3H7OOH 4.80E+12 0 0

4 R20C4H9=R22C4H9 3.30E+09 1 37000 39 R4CH3+R21C3H7=>C4H10 1.50E+13 0 0

5 R19C3H7=>R4CH3+C2H4Z 2.00E+13 0 31000 40 R5CHO+R21C3H7=>C3H7CHO 5.20E+12 0 0

6 R19C3H7=>R1H+C3H6Y 3.00E+13 0 38000 41 R6CH2OH+R21C3H7=>C4H9OH 5.10E+12 0 0

7 R20C4H9=>R11C2H5+C2H4Z 2.00E+13 0 28700 42 R7CH3O+R21C3H7=>C4H10O 4.90E+12 0 0

8 R20C4H9=>R1H+C4H8Y 3.00E+13 0 38000 43 R8CH3OO+R21C3H7=>C4H10OO 4.40E+12 0 0

9 R21C3H7=>R1H+C3H6Y 6.00E+13 0 39000 44 R11C2H5+R21C3H7=>C5H12 5.20E+12 0 0

10 R22C4H9=>R4CH3+C3H6Y 2.00E+13 0 31000 45 R21C3H7+R21C3H7=>C6H14 2.30E+12 0 0

11 R22C4H9=>R1H+C4H8Y 3.00E+13 0 38000 46 C3H7OOH=>R2OH+HCHO+R11C2H5 1.50E+16 0 42000

12 R22C4H9=>R1H+C4H8Y 3.00E+13 0 39000 47 C3H5OOHY=>R2OH+HCHO+R10C2H3V 1.50E+16 0 42000

13 R19C3H7+O2=>C3H6Y+R3OOH 2.80E+12 0 5000 48 C4H7OOHY=>R2OH+CH3CHO+R10C2H3V 1.50E+16 0 42000

14 R21C3H7+O2=>C3H6Y+R3OOH 2.30E+12 0 5000 49 C4H10+R1H=>H2+R11C2H5+C2H4Z 2.70E+07 2 5000

15 B1O+C3H8=>R2OH+R21C3H7 2.60E+13 0 5200 50 C4H10+R2OH=>H2O+R11C2H5+C2H4Z 7.80E+06 2 -765

16 B1O+C3H8=>R2OH+R19C3H7 1.00E+14 0 7850 51 C4H10+R3OOH=>H2O2+R11C2H5+C2H4Z 1.20E+12 0 15500

17 C3H8+R1H=>H2+R21C3H7 9.00E+06 2 5000 52 C4H10+R4CH3=>CH4+R11C2H5+C2H4Z 6.00E+11 0 9600

18 C3H8+R1H=>H2+R19C3H7 5.70E+07 2 7700 53 C4H10+R8CH3OO=>CH3OOH+R11C2H5+C2H4Z 4.50E+12 0 17500

19 C3H8+R2OH=>H2O+R21C3H7 2.60E+06 2 -765 54 C4H10+R11C2H5=>C2H6+R11C2H5+C2H4Z 6.00E+11 0 11000

20 C3H8+R2OH=>H2O+R19C3H7 5.40E+06 2 450 55 C5H12+R1H=>H2+R4CH3+2C2H4Z 2.70E+07 2 5000

21 C3H8+R3OOH=>H2O2+R21C3H7 4.00E+11 0 15500 56 C5H12+R2OH=>H2O+R4CH3+2C2H4Z 7.80E+06 2 -765

22 C3H8+R3OOH=>H2O2+R19C3H7 1.20E+12 0 17000 57 C5H12+R3OOH=>H2O2+R4CH3+2C2H4Z 1.20E+12 0 15500

23 C3H8+R4CH3=>CH4+R21C3H7 2.00E+11 0 9600 58 C5H12+R4CH3=>CH4+R4CH3+2C2H4Z 6.00E+11 0 9600

24 C3H8+R4CH3=>CH4+R19C3H7 6.00E-01 4 8200 59 C5H12+R8CH3OO=>CH3OOH+R4CH3+2C2H4Z 4.50E+12 0 17500

25 C3H8+R5CHO=>HCHO+R21C3H7 1.00E+07 1.9 17000 60 C5H12+R11C2H5=>C2H6+R4CH3+2C2H4Z 6.00E+11 0 11000

26 C3H8+R5CHO=>HCHO+R19C3H7 2.00E+05 2.5 18500 61 C6H14+R1H=>H2+R11C2H5+2C2H4Z 2.70E+07 2 5000

27 C3H8+R6CH2OH=>CH3OH+R21C3H7 6.00E+01 3 12000 62 C6H14+R2OH=>H2O+R11C2H5+2C2H4Z 7.80E+06 2 -765

28 C3H8+R6CH2OH=>CH3OH+R19C3H7 2.00E+02 3 14000 63 C6H14+R3OOH=>H2O2+R11C2H5+2C2H4Z 1.20E+12 0 15500

29 C3H8+R7CH3O=>CH3OH+R21C3H7 1.50E+11 0 4500 64 C6H14+R4CH3=>CH4+R11C2H5+2C2H4Z 6.00E+11 0 9600

30 C3H8+R7CH3O=>CH3OH+R19C3H7 3.20E+11 0 7300 65 C6H14+R8CH3OO=>CH3OOH+R11C2H5+2C2H4Z 4.50E+12 0 17500

31 C3H8+R8CH3OO=>CH3OOH+R21C3H7 3.00E+12 0 17500 66 C6H14+R11C2H5=>C2H6+R11C2H5+2C2H4Z 6.00E+11 0 11000

32 C3H8+R8CH3OO=>CH3OOH+R19C3H7 1.20E+13 0 20000 67 C3H6O#3+R1H=>H2+CH2COZ+R4CH3 2.70E+07 2 5000

33 C3H8+R11C2H5=>C2H6+R21C3H7 2.00E+11 0 11000 68 C3H6O#3+R2OH=>H2O+CH2COZ+R4CH3 7.80E+06 2 -765

34 C3H8+R11C2H5=>C2H6+R19C3H7 6.00E+11 0 13500 69 C3H6O#3+R3OOH=>H2O2+CH2COZ+R4CH3 1.20E+12 0 15500

35 C3H8+R21C3H7=>C3H8+R19C3H7 8.40E-03 4.2 8700 70 C3H6O#3+R4CH3=>CH4+CH2COZ+R4CH3 6.00E+11 0 9600

279

Rex No Reaction A b Ea

Rex No Reaction A b Ea

71 C3H6O#3+R8CH3OO=>CH3OOH+CH2COZ+R4CH3 6.00E+11 0 9600 107 .C4H7Y+C4H8Y=>R10C2H3V+3C2H4Z 6.00E+09 0 11400

72 C3H6O#3+R11C2H5=>C2H6+CH2COZ+R4CH3 6.00E+11 0 11000 108 .C4H7Y+C3H6Y=>R4CH3+C2H2T+2C2H4Z 6.00E+09 0 11400

73 C4H8O#3+R1H=>H2+CH2COZ+R11C2H5 2.70E+07 2 5000 109 C3H7OH+R1H=>H2+R2OH+C3H6Y 9.00E+06 2 5000

74 C4H8O#3+R2OH=>H2O+CH2COZ+R11C2H5 7.80E+06 2 -765 110 C3H7OH+R2OH=>H2O+R2OH+C3H6Y 1.30E+06 2 -765

75 C4H8O#3+R3OOH=>H2O2+CH2COZ+R11C2H5 1.20E+12 0 15500 111 C3H7OH+R3OOH=>H2O2+R2OH+C3H6Y 4.00E+11 0 15500

76 C4H8O#3+R4CH3=>CH4+CH2COZ+R11C2H5 6.00E+11 0 9600 112 C3H7OH+R4CH3=>CH4+R2OH+C3H6Y 2.00E+11 0 9600

77 C4H8O#3+R8CH3OO=>CH3OOH+CH2COZ+R11C2H5 6.00E+11 0 9600 113 C3H7OH+R8CH3OO=>CH3OOH+R2OH+C3H6Y 3.00E+12 0 17500

78 C4H8O#3+R11C2H5=>C2H6+CH2COZ+R11C2H5 6.00E+11 0 11000 114 C3H7OH+R11C2H5=>C2H6+R2OH+C3H6Y 2.00E+11 0 11000

79 C3H6O#3+B1O=>R2OH+R5CHO+C2H4Z 7.80E+13 0 5200 115 C4H9OH+R1H=>H2+R2OH+C4H8Y 9.00E+06 2 5000

80 C4H8O#3+B1O=>R2OH+R13CH2CHO+C2H4Z 7.80E+13 0 5200 116 C4H9OH+R1H=>H2+R4CH3+C2H6CO 4.20E+06 2 2400

81 C3H6Y+R1H=>C2H4Z+R4CH3 7.20E+12 0 2900 117 C4H9OH+R2OH=>H2O+R2OH+C4H8Y 1.30E+06 2 -765

82 C4H8Y+R1H=>C2H4Z+R11C2H5 7.20E+12 0 2900 118 C4H9OH+R2OH=>H2O+R4CH3+C2H6CO 4.00E+12 0 443

83 C3H6Y+R2OH=>R4CH3+CH3CHO 1.40E+12 0 -900 119 C4H9OH+R3OOH=>H2O2+R2OH+C4H8Y 4.00E+11 0 15500

84 C4H8Y+R2OH=>R4CH3+C2H5CHO 1.40E+12 0 -900 120 C4H9OH+R3OOH=>H2O2+R4CH3+C2H6CO 1.00E+12 0 14000

85 C3H6Y+R2OH=>HCHO+R11C2H5 1.40E+12 0 -900 121 C4H9OH+R4CH3=>CH4+R2OH+C4H8Y 2.00E+11 0 9600

86 C4H8Y+R2OH=>HCHO+R4CH3+C2H4Z 1.40E+12 0 -900 122 C4H9OH+R4CH3=>CH4+R4CH3+C2H6CO 1.00E+11 0 7600

87 C4H8Y+B1O=>CH2COZ+R11C2H5+R1H 3.40E+07 1.8 550 123 C4H9OH+R8CH3OO=>CH3OOH+R2OH+C4H8Y 3.00E+12 0 17500

88 C3H6Y+B1O=>CH2COZ+R4CH3+R1H 3.40E+07 1.8 550 124 C4H9OH+R11C2H5=>C2H6+R2OH+C4H8Y 2.00E+11 0 11000

89 C3H6Y+R3OOH=>R2OH+C3H6O#3 1.00E+12 0 14400 125 C4H9OH+R11C2H5=>C2H6+R4CH3+C2H6CO 1.00E+11 0 9200

90 C4H8Y+R3OOH=>R2OH+C4H8O#3 1.00E+12 0 14400 126 C3H7OH+B1O=>R2OH+R2OH+C3H6Y 9.00E+06 2 5000

91 C3H6Y+R1H=>.C3H5Y+H2 5.70E+04 2.5 290 127 C4H9OH+B1O=>R2OH+R2OH+C4H8Y 9.00E+06 2 5000

92 C3H6Y+R2OH=>.C3H5Y+H2O 3.00E+06 2 -1515 128 C4H9OH+B1O=>R2OH+R4CH3+C2H6CO 4.20E+06 2 2400

93 C3H6Y+R3OOH=>.C3H5Y+H2O2 6.30E+03 2.6 12400 129 C2H5CHO+R1H=>H2+.COC2H5 4.00E+13 0 4200

94 C3H6Y+R4CH3=>.C3H5Y+CH4 1.30E+00 3.5 3575 130 C2H5CHO+R2OH=>H2O+.COC2H5 4.20E+12 0 500

95 C3H6Y+R8CH3OO=>.C3H5Y+CH3OOH 2.00E+12 0 17050 131 C2H5CHO+R3OOH=>H2O2+.COC2H5 1.00E+12 0 10000

96 C3H6Y+R11C2H5=>.C3H5Y+C2H6 1.40E+00 3.5 4335 132 C2H5CHO+R4CH3=>CH4+.COC2H5 2.00E-06 5.6 2500

97 C4H8Y+R1H=>.C4H7Y+H2 5.70E+04 2.5 290 133 C2H5CHO+R11C2H5=>C2H6+.COC2H5 1.30E+12 0 8500

98 C4H8Y+R2OH=>.C4H7Y+H2O 3.00E+06 2 -1515 134 C2H3CHOZ+R1H=>H2+.COC2H3Z 4.00E+13 0 4200

99 C4H8Y+R3OOH=>.C4H7Y+H2O2 6.30E+03 2.6 12400 135 C2H3CHOZ+R2OH=>H2O+.COC2H3Z 4.20E+12 0 500

100 C4H8Y+R4CH3=>.C4H7Y+CH4 1.30E+00 3.5 3575 136 C2H3CHOZ+R3OOH=>H2O2+.COC2H3Z 1.00E+12 0 10000

101 C4H8Y+R8CH3OO=>.C4H7Y+CH3OOH 2.00E+12 0 17050 137 C2H3CHOZ+R4CH3=>CH4+.COC2H3Z 2.00E-06 5.6 2500

102 C4H8Y+R11C2H5=>.C4H7Y+C2H6 1.40E+00 3.5 4335 138 C2H3CHOZ+R11C2H5=>C2H6+.COC2H3Z 1.30E+12 0 8500

103 C3H6Y+B1O=>.C3H5Y+R2OH 9.10E+10 0.7 3830 139 C3H7CHO+R1H=>H2+.COC3H7 4.00E+13 0 4200

104 C4H8Y+B1O=>.C4H7Y+R2OH 9.10E+10 0.7 3830 140 C3H7CHO+R2OH=>H2O+.COC3H7 4.20E+12 0 500

105 .C3H5Y+C4H8Y=>R4CH3+C2H2T+2C2H4Z 6.00E+09 0 11400 141 C3H7CHO+R3OOH=>H2O2+.COC3H7 1.00E+12 0 10000

106 .C3H5Y+C3H6Y=>R10C2H3V+2C2H4Z 6.00E+09 0 11400 142 C3H7CHO+R4CH3=>CH4+.COC3H7 2.00E-06 5.6 2500

280

Rex No Reaction A b Ea

Rex No Reaction A b Ea

143 C3H7CHO+R11C2H5=>C2H6+.COC3H7 1.30E+12 0 8500 179 .C3H5Y+.C3H5Y=>C6H10Y2 1.00E+13 0 0

144 .COC2H5=>B2CO+R11C2H5 2.00E+13 0 28700 180 .C3H5Y+.C4H7Y=>C7H12Y2 1.00E+13 0 0

145 .COC3H7=>B2CO+R4CH3+C2H4Z 2.00E+13 0 28700 181 .C4H7Y+.C4H7Y=>C8H14Y2 1.00E+13 0 0

146 .COC2H5+O2=>.COOOC2H5 3.00E+19 -2.5 0 182 R1H+R1H+M=H2+M 1.87E+18 -1 0

147 .COC3H7+O2=>.COOOC3H7 3.00E+19 -2.5 0 183 B4CH+R1H=B3C+H2 7.80E+13 0 0

148 .COOOC2H5=>C2H4Z+R2OH+CO2 4.50E+11 0 25000 184 B6CH2+M=B5CH2+M 1.51E+13 0 0

149 .COOOC3H7=>C3H6Y+R2OH+CO2 4.50E+11 0 25000 185 B6CH2+R1H=B4CH+H2 3.00E+13 0 0

150 C2H6CO+R1H=>H2+CH2COZ+R4CH3 2.70E+07 2 5000 186 B5CH2+R1H=B4CH+H2 6.00E+12 0 -1800

151 C2H6CO+R2OH=>H2O+CH2COZ+R4CH3 7.80E+06 2 -765 187 B5CH2+B3C=R9C2HT+R1H 5.00E+13 0 0

152 C2H6CO+R3OOH=>H2O2+CH2COZ+R4CH3 1.20E+12 0 15500 188 B5CH2+B5CH2=>C2H2T+R1H+R1H 1.20E+14 0 800

153 C2H6CO+R4CH3=>CH4+CH2COZ+R4CH3 6.00E+11 0 9600 189 R4CH3+M=B5CH2+R1H+M 2.91E+16 0 90700

154 C2H6CO+R8CH3OO=>CH3OOH+CH2COZ+R4CH3 6.00E+11 0 9600 190 R4CH3+R1H=B6CH2+H2 6.00E+13 0 15000

155 C2H6CO+R11C2H5=>C2H6+CH2COZ+R4CH3 6.00E+11 0 11000 191 R4CH3+B4CH=R10C2H3V+R1H 3.00E+13 0 0

156 C3H8CO+R1H=>H2+CH2COZ+R11C2H5 2.70E+07 2 5000 192 R4CH3+B6CH2=C2H4Z+R1H 1.80E+13 0 0

157 C3H8CO+R2OH=>H2O+CH2COZ+R11C2H5 7.80E+06 2 -765 193 R4CH3+B5CH2=C2H4Z+R1H 4.20E+13 0 0

158 C3H8CO+R3OOH=>H2O2+CH2COZ+R11C2H5 1.20E+12 0 15500 194 R4CH3+B3C=C2H2T+R1H 5.00E+13 0 0

159 C3H8CO+R4CH3=>CH4+CH2COZ+R11C2H5 6.00E+11 0 9600 195 R4CH3+R4CH3(+M)=>C2H6(+M) 3.61E+13 0 0

160 C3H8CO+R8CH3OO=>CH3OOH+CH2COZ+R11C2H5 6.00E+11 0 9600 196 C2H6(+M)=>R4CH3+R4CH3(+M) 1.80E+21 -1.2 90900

161 C3H8CO+R11C2H5=>C2H6+CH2COZ+R11C2H5 6.00E+11 0 11000 197 R4CH3+R4CH3=R11C2H5+R1H 3.00E+13 0 13500

162 C4H6Z2+C2H4Z=>C6H10Z#6 3.00E+10 0 27500 198 R4CH3+R4CH3=C2H4Z+H2 2.10E+14 0 19300

163 .C3H5Y+R1H=>C3H6Y 1.00E+13 0 0 199 R1H+R4CH3(+M)=>CH4(+M) 1.67E+14 0 0

164 .C3H5Y+R2OH=>C3H5OHY 1.00E+13 0 0 200 CH4(+M)=>R4CH3+R1H(+M) 2.40E+16 0 105000

165 .C3H5Y+R3OOH=>C3H5OOHY 5.00E+12 0 0 201 CH4(+CH4)=>R4CH3+R1H(+CH4) 2.40E+16 0 105000

166 .C3H5Y+R4CH3=>C4H8Y 1.00E+13 0 0 202 CH4+R1H=R4CH3+H2 1.30E+04 3 8000

167 .C3H5Y+R5CHO=>C3H5CHOY 1.00E+13 0 0 203 CH4+B4CH=C2H4Z+R1H 3.00E+13 0 -400

168 .C3H5Y+R6CH2OH=>C4H7OHY 1.00E+13 0 0 204 CH4+B6CH2=R4CH3+R4CH3 4.20E+13 0 0

169 .C3H5Y+R8CH3OO=>C4H8OOY 1.00E+13 0 0 205 R9C2HT+B6CH2=C2H2T+B4CH 1.80E+13 0 0

170 .C3H5Y+R11C2H5=>C5H10Y 1.00E+13 0 0 206 R9C2HT+B5CH2=C2H2T+B4CH 1.80E+13 0 0

171 .C4H7Y+R1H=>C4H8Y 1.00E+13 0 0 207 R9C2HT+CH4=C2H2T+R4CH3 1.20E+12 0 0

172 .C4H7Y+R2OH=>C4H7OHY 1.00E+13 0 0 208 C2H2T+M=R9C2HT+R1H+M 1.14E+17 0 107000

173 .C4H7Y+R3OOH=>C4H7OOHY 5.00E+12 0 0 209 C2H2T+R1H=R9C2HT+H2 6.60E+13 0 27700

174 .C4H7Y+R4CH3=>C5H10Y 1.00E+13 0 0 210 R10C2H3V(+M)=C2H2T+R1H(+M) 2.00E+14 0 39800

175 .C4H7Y+R5CHO=>C4H7CHOY 1.00E+13 0 0 211 R10C2H3V+R1H=C2H2T+H2 1.20E+13 0 0

176 .C4H7Y+R6CH2OH=>C5H9OHY 1.00E+13 0 0 212 R10C2H3V+B6CH2=C2H2T+R4CH3 1.80E+13 0 0

177 .C4H7Y+R8CH3OO=>C5H10OOY 1.00E+13 0 0 213 R10C2H3V+B5CH2=C2H2T+R4CH3 1.80E+13 0 0

178 .C4H7Y+R11C2H5=>C6H12Y 1.00E+13 0 0 214 R10C2H3V+R4CH3=CH4+C2H2T 3.90E+11 0 0

281

Rex No Reaction A b Ea

Rex No Reaction A b Ea

215 R10C2H3V+R9C2HT=2C2H2T 9.60E+11 0 0 251 B1O+R10C2H3V=CH2COZ+R1H 9.60E+13 0 0

216 R10C2H3V+R10C2H3V=C2H4Z+C2H2T 9.60E+11 0 0 252 B1O+C2H4Z=R4CH3+R5CHO 8.10E+06 1.9 200

217 C2H4Z+M=C2H2T+H2+M 9.97E+16 0 71600 253 B1O+C2H4Z=HCHO+B5CH2 4.00E+05 1.9 200

218 C2H4Z+M=R10C2H3V+R1H+M 7.40E+17 0 96700 254 B1O+C2H4Z=CH2COZ+H2 6.60E+05 1.9 200

219 C2H4Z+R1H=R10C2H3V+H2 5.00E+07 1.9 13000 255 B1O+C2H4Z=R13CH2CHO+R1H 4.70E+06 1.9 200

220 C2H4Z+R4CH3=CH4+R10C2H3V 6.30E+11 0 16000 256 B1O+C2H4Z=R2OH+R10C2H3V 1.50E+07 1.9 3700

221 R11C2H5(+M)=C2H4Z+R1H(+M) 8.20E+13 0 40000 257 B1O+R11C2H5=HCHO+R4CH3 1.10E+13 0 0

222 R11C2H5+R1H=C2H4Z+H2 1.80E+12 0 0 258 B1O+R11C2H5=CH3CHO+R1H 5.50E+13 0 0

223 R11C2H5+R1H=C2H6 3.60E+13 0 0 259 B1O+R11C2H5=C2H4Z+R2OH 3.00E+13 0 0

224 R11C2H5+B6CH2=C2H4Z+R4CH3 9.00E+12 0 0 260 B1O+C2H6=R11C2H5+R2OH 1.00E+09 1.5 5800

225 R11C2H5+B5CH2=C2H4Z+R4CH3 1.80E+13 0 0 261 R1H+B1O+M=R2OH+M 1.18E+19 -1 0

226 R11C2H5+R4CH3=C2H4Z+CH4 1.10E+12 0 0 262 R1H+R2OH+M=H2O+M 5.53E+22 -2 0

227 R11C2H5+R9C2HT=C2H2T+C2H4Z 1.80E+12 0 0 263 R2OH+H2=R1H+H2O 1.00E+08 1.6 3300

228 R11C2H5+R10C2H3V=2C2H4Z 4.80E+11 0 0 264 R2OH+B3C=B2CO+R1H 5.00E+13 0 0

229 R11C2H5+R10C2H3V=C2H2T+C2H6 4.80E+11 0 0 265 R2OH+B4CH=R5CHO+R1H 3.00E+13 0 0

230 R11C2H5+R11C2H5=C2H4Z+C2H6 1.40E+12 0 0 266 R2OH+B6CH2=HCHO+R1H 3.00E+13 0 0

231 C2H6+M=C2H4Z+H2+M 2.30E+17 0 67400 267 R2OH+B5CH2=HCHO+R1H 1.80E+13 0 0

232 C2H6+R1H=R11C2H5+H2 1.40E+09 1.5 7400 268 R2OH+R4CH3=B6CH2+H2O 7.20E+13 0 2700

233 C2H6+B6CH2=R4CH3+R11C2H5 1.10E+14 0 0 269 R2OH+R4CH3(+M)=CH3OH(+M) 6.00E+13 0 0

234 C2H6+R4CH3=R11C2H5+CH4 1.50E-07 6 5800 270 R2OH+R4CH3=HCHO+H2 3.20E+12 -0.5 10800

235 C2H6+R9C2HT=C2H2T+R11C2H5 3.60E+12 0 0 271 R2OH+R4CH3=R7CH3O+R1H 5.70E+12 -0.2 13900

236 C2H6+R10C2H3V=R11C2H5+C2H4Z 6.00E+02 3.3 10500 272 R2OH+CH4=R4CH3+H2O 1.60E+07 1.8 2700

237 B1O+H2=R2OH+R1H 5.10E+04 2.7 6200 273 R2OH+R9C2HT=C2H2T+B1O 1.80E+13 0 0

238 B1O+B4CH=B2CO+R1H 3.90E+13 0 0 274 R2OH+R9C2HT=B5CH2+B2CO 1.80E+13 0 0

239 B1O+B4CH=B3C+R2OH 1.50E+13 0 4700 275 R2OH+R9C2HT=R12CHCOV+R1H 2.00E+13 0 0

240 B1O+B6CH2=>B2CO+2R1H 1.50E+13 0 0 276 R2OH+C2H2T=R9C2HT+H2O 1.40E+04 2.7 12000

241 B1O+B6CH2=B2CO+H2 1.50E+13 0 0 277 R2OH+C2H2T=CH2COZ+R1H 2.20E-04 4.5 -1000

242 B1O+B5CH2=>B2CO+2R1H 7.20E+13 0 0 278 R2OH+C2H2T=R4CH3+B2CO 4.80E-04 4 -2000

243 B1O+B5CH2=B2CO+H2 4.80E+13 0 0 279 R2OH+R10C2H3V=C2H2T+H2O 3.00E+13 0 0

244 B1O+R4CH3=HCHO+R1H 8.40E+13 0 0 280 R2OH+R10C2H3V=CH3CHO 3.00E+13 0 0

245 B1O+R4CH3=R7CH3O 8.00E+15 -2.1 600 281 R2OH+C2H4Z=R10C2H3V+H2O 2.00E+13 0 5900

246 B1O+CH4=R4CH3+R2OH 7.20E+08 1.6 8400 282 R2OH+C2H4Z=R4CH3+HCHO 2.00E+12 0 900

247 B1O+R9C2HT=B4CH+B2CO 1.00E+13 0 0 283 R2OH+R11C2H5=C2H4Z+H2O 2.40E+13 0 0

248 B1O+C2H2T=B5CH2+B2CO 2.17E+06 2.1 1600 284 R2OH+R11C2H5=>R4CH3+R1H+HCHO 2.40E+13 0 0

249 B1O+C2H2T=R12CHCOV+R1H 5.06E+06 2.1 1600 285 R2OH+C2H6=R11C2H5+H2O 7.20E+06 2 900

250 B1O+R10C2H3V=R4CH3+B2CO 3.00E+13 0 0 286 R2OH+R2OH=H2O+B1O 1.50E+09 1.1 100

282

Rex No Reaction A b Ea

Rex No Reaction A b Ea

287 H2O+B4CH=R6CH2OH 5.70E+12 0 -800 323 R7CH3O+R10C2H3V=HCHO+C2H4Z 2.40E+13 0 0

288 H2O+B6CH2=CH3OH 1.80E+13 0 0 324 R7CH3O+C2H4Z=HCHO+R11C2H5 1.20E+11 0 6700

289 B2CO+R4CH3(+M)=R14CH3CO(+M) 5.00E+11 0 6900 325 R7CH3O+R11C2H5=HCHO+C2H6 2.40E+13 0 0

290 B2CO+B1O+M=CO2+M 1.54E+15 0 3000 326 R7CH3O+C2H6=R11C2H5+CH3OH 2.40E+11 0 7000

291 B2CO+R2OH=CO2+R1H 6.30E+06 1.5 -500 327 R7CH3O+B1O=HCHO+R2OH 1.80E+12 0 0

292 R5CHO+M=R1H+B2CO+M 1.90E+17 -1 17000 328 R7CH3O+R2OH=HCHO+H2O 1.80E+13 0 0

293 R5CHO+R1H=H2+B2CO 9.00E+13 0 0 329 R7CH3O+B2CO=R4CH3+CO2 1.60E+13 0 11700

294 R5CHO+R1H=B1O+B5CH2 4.00E+13 0 102500 330 R7CH3O+R5CHO=CH3OH+B2CO 9.10E+13 0 0

295 R5CHO+B6CH2=R4CH3+B2CO 1.80E+13 0 0 331 R7CH3O+HCHO=CH3OH+R5CHO 1.00E+11 0 3000

296 R5CHO+B5CH2=R4CH3+B2CO 1.80E+13 0 0 332 R7CH3O+R7CH3O=CH3OH+HCHO 6.00E+13 0 0

297 R5CHO+R4CH3=CH4+B2CO 1.20E+14 0 0 333 R6CH2OH+M=HCHO+R1H+M 1.26E+16 0 30000

298 R5CHO+R4CH3=CH3CHO 1.80E+13 0 0 334 R6CH2OH+R1H=R4CH3+R2OH 9.60E+13 0 0

299 R4CH3+HCHO=R5CHO+CH4 7.70E-08 6.1 1970 335 R6CH2OH+R1H=HCHO+H2 6.00E+12 0 0

300 R5CHO+R9C2HT=C2H2T+B2CO 6.00E+13 0 0 336 R6CH2OH+H2=CH3OH+R1H 6.70E+05 2 13400

301 R5CHO+R10C2H3V=C2H4Z+B2CO 9.00E+13 0 0 337 R6CH2OH+B6CH2=CH3CHO+R1H 1.80E+13 0 0

302 R10C2H3V+HCHO=R5CHO+C2H4Z 5.40E+03 2.8 5900 338 R6CH2OH+B5CH2=C2H4Z+R2OH 2.40E+13 0 0

303 R5CHO+R11C2H5=C2H6+B2CO 1.20E+14 0 0 339 R6CH2OH+B5CH2=R4CH3+HCHO 1.20E+12 0 0

304 R11C2H5+HCHO=R5CHO+C2H6 5.57E+03 2.8 5860 340 R6CH2OH+R4CH3=C2H5OH 1.20E+13 0 0

305 R5CHO+B1O=R1H+CO2 3.00E+13 0 0 341 R6CH2OH+R4CH3=CH4+HCHO 2.40E+12 0 0

306 R5CHO+B1O=R2OH+B2CO 3.00E+13 0 0 342 R6CH2OH+CH4=CH3OH+R4CH3 2.17E+01 3.1 16200

307 R5CHO+R2OH=H2O+B2CO 1.10E+14 0 0 343 R6CH2OH+R9C2HT=C2H2T+HCHO 4.80E+13 0 0

308 R5CHO+R5CHO=HCHO+B2CO 3.00E+13 0 0 344 R6CH2OH+C2H2T=R10C2H3V+HCHO 7.20E+11 0 9000

309 HCHO+M=R5CHO+R1H+M 1.40E+36 -5.5 96800 345 R6CH2OH+R10C2H3V=C2H4Z+HCHO 4.20E+13 0 0

310 HCHO+M=H2+B2CO+M 3.26E+36 -5.5 96800 346 R6CH2OH+R11C2H5=C2H4Z+CH3OH 2.40E+12 0 0

311 HCHO+R1H=R5CHO+H2 1.30E+08 1.6 2100 347 R6CH2OH+R11C2H5=C2H6+HCHO 2.40E+12 0 0

312 HCHO+B4CH=R13CH2CHO 9.60E+13 0 -500 348 R6CH2OH+C2H6=CH3OH+R11C2H5 1.99E+02 3 14000

313 HCHO+B6CH2=R4CH3+R5CHO 1.20E+12 0 0 349 R6CH2OH+B1O=HCHO+R2OH 4.20E+13 0 0

314 HCHO+B1O=R5CHO+R2OH 4.10E+11 0.6 2700 350 R6CH2OH+R2OH=H2O+HCHO 2.40E+13 0 0

315 HCHO+R2OH=R5CHO+H2O 3.40E+09 1.2 -400 351 R6CH2OH+R5CHO=CH3OH+B2CO 1.20E+14 0 0

316 R7CH3O+M=HCHO+R1H+M 1.55E+14 0 13500 352 R6CH2OH+R5CHO=HCHO+HCHO 1.80E+14 0 0

317 R7CH3O+R1H=HCHO+H2 1.80E+13 0 0 353 R6CH2OH+HCHO=CH3OH+R5CHO 5.50E+03 2.8 5900

318 R7CH3O+B6CH2=R4CH3+HCHO 1.80E+13 0 0 354 R6CH2OH+R7CH3O=CH3OH+HCHO 2.40E+13 0 0

319 R7CH3O+B5CH2=R4CH3+HCHO 1.80E+13 0 0 355 R6CH2OH+R6CH2OH=CH3OH+HCHO 1.40E+13 0 0

320 R7CH3O+R4CH3=HCHO+CH4 2.40E+13 0 0 356 CH3OH+R1H=R4CH3+H2O 2.00E+14 0 5300

321 R7CH3O+CH4=R4CH3+CH3OH 1.60E+11 0 8800 357 CH3OH+R1H=R7CH3O+H2 4.20E+06 2.1 4900

322 R7CH3O+R9C2HT=HCHO+C2H2T 2.40E+13 0 0 358 CH3OH+B6CH2=R6CH2OH+R4CH3 1.50E+12 0 0

283

Rex No Reaction A b Ea

Rex No Reaction A b Ea

359 CH3OH+B5CH2=R4CH3+R6CH2OH 3.19E+01 3.2 7200 395 R14CH3CO+R7CH3O=CH3OH+CH2COZ 6.00E+12 0 0

360 CH3OH+B5CH2=R4CH3+R7CH3O 1.44E+01 3.1 6900 396 R14CH3CO+R7CH3O=HCHO+CH3CHO 6.00E+12 0 0

361 CH3OH+R9C2HT=C2H2T+R6CH2OH 6.00E+12 0 0 397 R14CH3CO+CH3OH=CH3CHO+R6CH2OH 4.85E+03 3 12300

362 CH3OH+R9C2HT=C2H2T+R7CH3O 1.20E+12 0 0 398 R14CH3CO+R14CH3CO=CH2COZ+CH3CHO 1.20E+13 0 0

363 CH3OH+R10C2H3V=C2H4Z+R6CH2OH 3.19E+01 3.2 7200 399 R13CH2CHO=R14CH3CO 1.00E+13 0 47000

364 CH3OH+R10C2H3V=C2H4Z+R7CH3O 1.44E+01 3.1 6900 400 R13CH2CHO=R1H+CH2COZ 1.60E+13 0 35000

365 CH3OH+B1O=R6CH2OH+R2OH 3.40E+13 0 5500 401 CH3CHO+R1H=H2+R14CH3CO 4.00E+13 0 4200

366 CH3OH+B1O=R7CH3O+R2OH 1.00E+13 0 4700 402 CH3CHO+R4CH3=R14CH3CO+CH4 2.00E-06 5.6 2500

367 CH3OH+R2OH=R6CH2OH+H2O 3.10E+06 2 -340 403 CH3CHO+R10C2H3V=C2H4Z+R14CH3CO 8.10E+10 0 3700

368 CH3OH+R2OH=R7CH3O+H2O 5.40E+05 2 -340 404 CH3CHO+R11C2H5=C2H6+R14CH3CO 1.30E+12 0 8500

369 CH3OH+R7CH3O=CH3OH+R6CH2OH 3.00E+11 0 4100 405 CH3CHO+B1O=R14CH3CO+R2OH 1.40E+13 0 2300

370 R12CHCOV+M=B4CH+B2CO+M 6.00E+15 0 58800 406 CH3CHO+R2OH=R14CH3CO+H2O 4.20E+12 0 500

371 R12CHCOV+R1H=B5CH2+B2CO 1.50E+14 0 0 407 CH3CHO+R7CH3O=R14CH3CO+CH3OH 2.40E+11 0 1800

372 R12CHCOV+R1H=B6CH2+B2CO 1.30E+14 0 0 408 CH3CHO+R13CH2CHO=CH3CHO+R14CH3CO 2.50E+07 0 0

373 R12CHCOV+B5CH2=R9C2HT+HCHO 1.00E+13 0 2000 409 C2H4O#3=CH4+B2CO 1.20E+13 0 57200

374 R12CHCOV+B5CH2=R10C2H3V+B2CO 3.00E+13 0 0 410 C2H4O#3=CH3CHO 7.30E+13 0 57200

375 R12CHCOV+B1O=>B2CO+B2CO+R1H 9.60E+13 0 0 411 C2H4O#3=R4CH3+R5CHO 3.60E+13 0 57200

376 R12CHCOV+R2OH=>R5CHO+B2CO+R1H 1.00E+13 0 0 412 C2H4O#3+R1H=H2+R13CH2CHO 2.00E+13 0 8300

377 CH2COZ+M=B6CH2+B2CO+M 6.57E+15 0 57600 413 C2H4O#3+R1H=H2O+R10C2H3V 5.00E+09 0 5000

378 CH2COZ+M=R12CHCOV+R1H+M 2.70E+17 0 87000 414 C2H4O#3+R1H=C2H4Z+R2OH 9.50E+10 0 5000

379 CH2COZ+R1H=R4CH3+B2CO 1.80E+13 0 3400 415 C2H4O#3+R4CH3=CH4+R13CH2CHO 1.10E+12 0 11800

380 CH2COZ+R1H=R12CHCOV+H2 5.00E+13 0 8000 416 C2H4O#3+R4CH3=R11C2H5+HCHO 1.40E+11 0 7600

381 CH2COZ+B5CH2=C2H4Z+B2CO 1.30E+14 0 0 417 C2H4O#3+R4CH3=C2H4Z+R7CH3O 1.50E+10 0 7600

382 CH2COZ+B1O=B5CH2+CO2 1.80E+12 0 1300 418 C2H4O#3+R9C2HT=C2H2T+R13CH2CHO 1.20E+12 0 9800

383 CH2COZ+B1O=R12CHCOV+R2OH 1.00E+13 0 8000 419 C2H4O#3+R10C2H3V=C2H4Z+R13CH2CHO 2.00E+12 0 9300

384 CH2COZ+R2OH=R12CHCOV+H2O 7.50E+12 0 2000 420 C2H4O#3+R11C2H5=C2H6+R13CH2CHO 6.80E+11 0 11400

385 CH2COZ+R2OH=R4CH3+CO2 2.52E+12 0 0 421 C2H4O#3+B1O=R2OH+R13CH2CHO 1.90E+12 0 5200

386 CH2COZ+R2OH=R6CH2OH+B2CO 4.68E+12 0 0 422 C2H4O#3+R2OH=H2O+R13CH2CHO 1.80E+13 0 3600

387 R14CH3CO+R1H=R4CH3+R5CHO 9.60E+13 0 0 423 C2H4O#3+R5CHO=HCHO+R13CH2CHO 3.70E+12 0 15800

388 R14CH3CO+B6CH2=R4CH3+CH2COZ 1.80E+13 0 0 424 C2H4O#3+R7CH3O=CH3OH+R13CH2CHO 1.30E+12 0 5800

389 R14CH3CO+B5CH2=R4CH3+CH2COZ 1.80E+13 0 0 425 C2H4O#3+R6CH2OH=CH3OH+R13CH2CHO 8.40E+11 0 13400

390 R14CH3CO+B1O=R4CH3+CO2 9.60E+12 0 0 426 C2H4O#3+R14CH3CO=CH3CHO+R13CH2CHO 4.00E+12 0 17500

391 R14CH3CO+R2OH=CH2COZ+H2O 1.20E+13 0 0 427 C2H4O#3+R13CH2CHO=CH3CHO+R13CH2CHO 6.80E+11 0 15400

392 R14CH3CO+R2OH=>R4CH3+B2CO+R2OH 3.00E+13 0 0 428 R15C2H5O=HCHO+R4CH3 8.00E+13 0 21500

393 R14CH3CO+R5CHO=CH3CHO+B2CO 9.00E+12 0 0 429 R15C2H5O=CH3CHO+R1H 2.00E+14 0 23300

394 R14CH3CO+HCHO=CH3CHO+R5CHO 1.80E+11 0 12900 430 C2H5OH(+M)=R11C2H5+R2OH(+M) 1.20E+23 -1.5 96000

284

Rex No Reaction A b Ea

Rex No Reaction A b Ea

431 C2H5OH(+M)=C2H4Z+H2O(+M) 2.80E+13 0.1 66100 467 O2+R9C2HT=R12CHCOV+B1O 9.00E+12 -0.2 0

432 C2H5OH(+M)=CH3CHO+H2(+M) 7.20E+11 0.1 91000 468 O2+C2H2T=R9C2HT+R3OOH 1.20E+13 0 74500

433 C2H5OH+R1H=H2+R15C2H5O 1.50E+07 1.6 3040 469 O2+C2H2T=R5CHO+R5CHO 7.00E+07 1.8 30600

434 C2H5OH+B1O=R2OH+R15C2H5O 1.60E+07 2 4450 470 O2+R10C2H3V=C2H2T+R3OOH 1.34E+06 1.6 -400

435 C2H5OH+R2OH=H2O+R15C2H5O 7.50E+11 0.3 1600 471 O2+R10C2H3V=HCHO+R5CHO 4.50E+16 -1.4 1000

436 C2H5OH+R3OOH=H2O2+R15C2H5O 2.50E+12 0 24000 472 O2+R10C2H3V=B1O+R13CH2CHO 3.30E+11 -0.3 10

437 C2H5OH+R4CH3=CH4+R15C2H5O 1.40E+02 3 7650 473 O2+C2H4Z=R10C2H3V+R3OOH 4.20E+13 0 57400

438 C2H5OH+R1H=H2+R2OH+C2H4Z 1.20E+07 1.8 5100 474 O2+R11C2H5=R17C2H5OO 2.20E+10 0.8 -600

439 C2H5OH+B1O=R2OH+R2OH+C2H4Z 9.40E+07 1.7 5460 475 O2+R11C2H5=C2H4Z+R3OOH 8.40E+11 0 3900

440 C2H5OH+R2OH=H2O+R2OH+C2H4Z 1.70E+11 0.3 600 476 O2+R11C2H5=R15C2H5O+B1O 1.20E+13 -0.2 27900

441 C2H5OH+R3OOH=H2O2+R2OH+C2H4Z 1.20E+04 2.5 15700 477 O2+R11C2H5=CH3CHO+R2OH 6.00E+10 0 6900

442 C2H5OH+R4CH3=CH4+R2OH+C2H4Z 2.20E+02 3.2 9600 478 O2+C2H6=R11C2H5+R3OOH 6.00E+13 0 51700

443 C2H5OH+R1H=H2+CH3CHO+R1H 2.60E+07 1.6 2800 479 O2+R2OH=R3OOH+B1O 2.20E+13 0 52500

444 C2H5OH+B1O=R2OH+CH3CHO+R1H 1.90E+07 1.9 1820 480 O2+B2CO=CO2+B1O 2.50E+12 0 47700

445 C2H5OH+R2OH=H2O+CH3CHO+R1H 4.60E+11 0.1 0 481 O2+R5CHO=B2CO+R3OOH 7.60E+12 0 410

446 C2H5OH+R3OOH=H2O2+CH3CHO+R1H 8.20E+03 2.5 10700 482 O2+HCHO=R5CHO+R3OOH 2.00E+13 0 38800

447 C2H5OH+R4CH3=CH4+CH3CHO+R1H 7.30E+02 3 7900 483 O2+R7CH3O=HCHO+R3OOH 2.20E+10 0 1700

448 B1O+B1O+M=O2+M 5.40E+13 0 -1790 484 O2+R6CH2OH=HCHO+R3OOH 1.20E+12 0 0

449 O2+R1H=R2OH+B1O 9.80E+13 0 14800 485 O2+CH3OH=R6CH2OH+R3OOH 2.00E+13 0 44900

450 O2+R1H(+M)=R3OOH(+M) 4.52E+13 0 0 486 O2+R12CHCOV=>B2CO+B2CO+R2OH 1.50E+12 0 2500

451 O2+R1H(+H2O)=R3OOH(+H2O) 4.52E+13 0 0 487 O2+R14CH3CO=R18CH3COOO 2.40E+12 0 0

452 O2+B3C=B2CO+B1O 1.20E+14 0 0 488 O2+R13CH2CHO=>HCHO+R2OH+B2CO 5.90E+09 0 -1400

453 O2+B4CH=R5CHO+B1O 3.30E+13 0 0 489 O2+R13CH2CHO=CH2COZ+R3OOH 1.00E+10 0 -1400

454 O2+B4CH=B2CO+R2OH 3.20E+13 0 0 490 O2+CH3CHO=R14CH3CO+R3OOH 5.00E+13 0 36400

455 O2+B6CH2=>B2CO+R2OH+R1H 3.10E+12 0 0 491 O2+CH3CHO=R13CH2CHO+R3OOH 1.00E+13 0.5 46000

456 O2+B5CH2=R5CHO+R2OH 4.30E+10 0 -500 492 O2+C2H4O#3=R3OOH+R13CH2CHO 5.00E+13 0 48000

457 O2+B5CH2=CO2+H2 6.90E+11 0 500 493 O2+R15C2H5O=CH3CHO+R3OOH 6.00E+10 0 1700

458 O2+B5CH2=>CO2+R1H+R1H 1.60E+12 0 1000 494 R3OOH+R1H=H2+O2 4.30E+13 0 1400

459 O2+B5CH2=B2CO+H2O 1.90E+10 0 -1000 495 R3OOH+R1H=2R2OH 1.70E+14 0 900

460 O2+B5CH2=>B2CO+R2OH+R1H 8.60E+10 0 -500 496 R3OOH+R1H=H2O+B1O 3.00E+13 0 1700

461 O2+B5CH2=HCHO+B1O 1.00E+14 0 4500 497 R3OOH+B6CH2=HCHO+R2OH 3.00E+13 0 0

462 O2+R4CH3(+M)=R8CH3OO(+M) 7.80E+08 1.2 0 498 R3OOH+B5CH2=HCHO+R2OH 1.80E+13 0 0

463 O2+R4CH3=R7CH3O+B1O 1.30E+14 0 31300 499 R3OOH+R4CH3=R7CH3O+R2OH 1.80E+13 0 0

464 O2+R4CH3=HCHO+R2OH 3.00E+30 -4.7 36600 500 R3OOH+CH4=R4CH3+H2O2 9.00E+12 0 24600

465 O2+CH4=R4CH3+R3OOH 4.00E+13 0 56700 501 R3OOH+R9C2HT=R12CHCOV+R2OH 1.80E+13 0 0

466 O2+R9C2HT=B2CO+R5CHO 3.80E+13 -0.2 0 502 R3OOH+C2H2T=CH2COZ+R2OH 6.00E+09 0 8000

285

Rex No Reaction A b Ea

Rex No Reaction A b Ea

503 R3OOH+R10C2H3V=>R2OH+R4CH3+B2CO 3.00E+13 0 0 539 R8CH3OO+R10C2H3V=R7CH3O+R13CH2CHO 2.40E+13 0 0

504 R3OOH+C2H4Z=CH3CHO+R2OH 6.00E+09 0 7900 540 R8CH3OO+C2H4Z=R7CH3O+C2H4O#3 1.10E+15 0 20000

505 R3OOH+C2H4Z=C2H4O#3+R2OH 2.20E+12 0 17200 541 R8CH3OO+C2H4Z=CH3OOH+R10C2H3V 3.90E+12 0 24500

506 R3OOH+R11C2H5=>R4CH3+HCHO+R2OH 2.40E+13 0 0 542 R8CH3OO+R11C2H5=R7CH3O+R15C2H5O 2.40E+13 0 0

507 R3OOH+R11C2H5=C2H4Z+H2O2 3.00E+11 0 0 543 R8CH3OO+C2H6=CH3OOH+R11C2H5 2.90E+11 0 14900

508 R3OOH+C2H6=R11C2H5+H2O2 1.30E+13 0 20400 544 R8CH3OO+B1O=R7CH3O+O2 3.60E+13 0 0

509 R3OOH+R2OH=H2O+O2 2.90E+13 0 -500 545 R8CH3OO+R2OH=CH3OH+O2 6.00E+13 0 0

510 R3OOH+B2CO=CO2+R2OH 1.50E+14 0 23600 546 R8CH3OO+R2OH=R7CH3O+R3OOH 3.00E+12 0 0

511 R3OOH+R5CHO=>R2OH+R1H+CO2 3.00E+13 0 0 547 R8CH3OO+B2CO=R7CH3O+CO2 1.00E+14 0 24000

512 R3OOH+HCHO=R5CHO+H2O2 3.00E+12 0 13000 548 R8CH3OO+R5CHO=>R7CH3O+R1H+CO2 3.00E+13 0 0

513 R3OOH+R7CH3O=HCHO+H2O2 3.00E+11 0 0 549 R8CH3OO+HCHO=CH3OOH+R5CHO 1.00E+12 0 12100

514 R3OOH+R6CH2OH=HCHO+H2O2 1.20E+13 0 0 550 R8CH3OO+R7CH3O=HCHO+CH3OOH 3.00E+11 0 0

515 R3OOH+CH3OH=R6CH2OH+H2O2 9.60E+10 0 12600 551 R8CH3OO+R6CH2OH=>R7CH3O+R2OH+HCHO 1.20E+13 0 0

516 R3OOH+R14CH3CO=>R4CH3+CO2+R2OH 3.00E+13 0 0 552 R8CH3OO+CH3OH=CH3OOH+R6CH2OH 1.80E+12 0 13700

517 R3OOH+CH3CHO=R14CH3CO+H2O2 1.00E+12 0 10000 553 R8CH3OO+CH3OH=CH3OOH+R7CH3O 2.80E+11 0 18800

518 R3OOH+C2H4O#3=H2O2+R13CH2CHO 1.60E+12 0 15000 554 R8CH3OO+CH2COZ=CH3OOH+R12CHCOV 1.70E+12 0 27000

519 R3OOH+R3OOH=H2O2+O2 1.30E+11 0 -1630 555 R8CH3OO+R14CH3CO=R4CH3+CO2+R7CH3O 2.40E+13 0 0

520 R3OOH+R3OOH=H2O2+O2 4.20E+14 0 11980 556 R8CH3OO+CH3CHO=CH3OOH+R14CH3CO 1.00E+12 0 12100

521 R2OH+R2OH(+M)=>H2O2(+M) 7.23E+13 -0.4 0 557 R8CH3OO+CH3CHO=CH3OOH+R13CH2CHO 1.70E+12 0 19200

522 H2O2(+M)=>R2OH+R2OH(+M) 3.00E+14 0 48500 558 R8CH3OO+C2H4O#3=CH3OOH+R13CH2CHO 2.20E+12 0 16000

523 H2O2+R1H=H2+R3OOH 1.70E+12 0 3700 559 R8CH3OO+R3OOH=CH3OOH+O2 2.50E+11 0 -1600

524 H2O2+R1H=H2O+R2OH 1.00E+13 0 3600 560 R8CH3OO+R3OOH=>O2+HCHO+H2O 5.00E+10 0 0

525 H2O2+B6CH2=R7CH3O+R2OH 3.00E+13 0 0 561 R8CH3OO+H2O2=CH3OOH+R3OOH 2.40E+12 0 9900

526 H2O2+R10C2H3V=C2H4Z+R3OOH 1.20E+10 0 -600 562 R8CH3OO+R8CH3OO=CH3OH+HCHO+O2 2.50E+10 0 -800

527 H2O2+B1O=R2OH+R3OOH 6.60E+11 0 4000 563 R8CH3OO+R8CH3OO=R7CH3O+R7CH3O+O2 2.50E+10 0 -800

528 H2O2+R2OH=H2O+R3OOH 7.80E+12 0 1300 564 CH3OOH=R7CH3O+R2OH 6.00E+14 0 42300

529 CO2+B5CH2=HCHO+B2CO 2.30E+10 0 0 565 CH3OOH+B1O=R8CH3OO+R2OH 2.00E+13 0 4800

530 R8CH3OO=HCHO+R2OH 1.50E+13 0 47000 566 CH3OOH+R2OH=H2O+R8CH3OO 1.80E+12 0 -370

531 R8CH3OO+R1H=R7CH3O+R2OH 9.60E+13 0 0 567 CH3OOH+R7CH3O=>CH3OH+R2OH+HCHO 1.50E+11 0 6500

532 R8CH3OO+H2=CH3OOH+R1H 3.00E+13 0 26000 568 R17C2H5OO=R16C2H4OOH 4.20E+12 0 36900

533 R8CH3OO+B6CH2=HCHO+R7CH3O 1.80E+13 0 0 569 R17C2H5OO+H2=C2H5OOH+R1H 7.90E+12 0 21000

534 R8CH3OO+B5CH2=HCHO+R7CH3O 1.80E+13 0 0 570 R17C2H5OO+R4CH3=R15C2H5O+R7CH3O 2.00E+12 0 -1200

535 R8CH3OO+R4CH3=R7CH3O+R7CH3O 5.00E+12 0 -1400 571 R17C2H5OO+CH4=C2H5OOH+R4CH3 3.90E+12 0 24000

536 R8CH3OO+CH4=CH3OOH+R4CH3 1.80E+11 0 18500 572 R17C2H5OO+C2H2T=C2H5OOH+R9C2HT 5.60E+11 0 24400

537 R8CH3OO+R9C2HT=R7CH3O+ R12CHCOV 2.40E+13 0 0 573 R17C2H5OO+C2H4Z=C2H5OOH+R10C2H3V 3.90E+12 0 24400

538 R8CH3OO+C2H2T=CH3OOH+R9C2HT 5.60E+11 0 24500 574 R17C2H5OO+C2H4Z=R15C2H5O+C2H4O#3 2.30E+16 0 21900

286

Rex No Reaction A b Ea

Rex No Reaction A b Ea

575 R17C2H5OO+C2H6=C2H5OOH+R11C2H5 5.10E+12 0 19500 611 R18CH3COOO+C2H5OOH=CH3COOOH+ R17C2H5OO 5.00E+11 0 9200

576 R17C2H5OO+H2O=C2H5OOH+R2OH 5.60E+12 0 30600 612 R18CH3COOO+C2H5OOH=>CH3CHO+ R2OH+CH3COOOH 5.00E+11 0 9200

577 R17C2H5OO+B2CO=CO2+R15C2H5O 1.00E+14 0 24000 613 R18CH3COOO+R18CH3COOO=>2R4CH3 +O2+2CO2 1.70E+12 0 -1000

578 R17C2H5OO+HCHO=C2H5OOH+R5CHO 4.50E+12 0 14400 614 CH3COOOH=>R4CH3+CO2+R2OH 1.00E+16 0 40000

579 R17C2H5OO+CH3OH=C2H5OOH+R7CH3O 2.80E+11 0 18400 615 C2H4Z+R4CH3=>R19C3H7 2.10E+11 0 7350

580 R17C2H5OO+CH3OH=C2H5OOH+R6CH2OH 2.80E+12 0 19500 616 R11C2H5+C2H4Z=>R20C4H9 1.10E+11 0 7300

581 R17C2H5OO+CH2COZ=C2H5OOH+R12CHCOV 1.70E+12 0 24400 617 R11C2H5+R10C2H3V=>C4H8Y 1.50E+13 0 0

582 R17C2H5OO+CH3CHO=C2H5OOH+R14CH3CO 3.90E+12 0 14400 618 R11C2H5+R11C2H5=>C4H10 1.10E+13 0 0

583 R17C2H5OO+CH3CHO=C2H5OOH+R13CH2CHO 1.70E+12 0 19500 619 R5CHO+R10C2H3V=>C2H3CHOZ 1.80E+13 0 0

584 R17C2H5OO+C2H4O#3=C2H5OOH+R13CH2CHO 2.20E+12 0 16300 620 R5CHO+R11C2H5=>C2H5CHO 1.80E+13 0 0

585 R17C2H5OO+R3OOH=O2+C2H5OOH 3.90E+11 0 -1300 621 R6CH2OH+R11C2H5=C3H7OH 1.20E+13 0 0

586 R17C2H5OO+H2O2=C2H5OOH+R3OOH 4.50E+11 0 10800 622 R14CH3CO+R4CH3=>C2H6CO 4.00E+15 -0.8 0

587 R17C2H5OO+R8CH3OO=>R15C2H5O+R7CH3O+O2 2.00E+11 0 0 623 R14CH3CO+R11C2H5=>C3H8CO 3.10E+14 -0.5 0

588 R17C2H5OO+CH3OOH=C2H5OOH+R8CH3OO 1.10E+12 0 16300 624 C2H3CHOZ+R2OH=B2CO+R10C2H3V+H2O 1.00E+13 0 0

589 R17C2H5OO+R17C2H5OO=2R15C2H5O+O2 4.10E+10 0 200 625 C2H3CHOZ+B1O=B2CO+R10C2H3V+R2OH 7.20E+12 0 2000

590 R17C2H5OO+R17C2H5OO=C2H5OH+CH3CHO+O2 1.80E+10 0 200 626 C2H3CHOZ+B1O=CH2COZ+R5CHO+R1H 5.00E+07 1.8 80

591 R16C2H4OOH=C2H4O#3+R2OH 1.50E+11 0 20000 627 C2H3CHOZ+R1H=B2CO+R10C2H3V+H2 4.00E+13 0 4200

592 R16C2H4OOH=R6CH2OH+HCHO 2.50E+13 0 27500 628 C2H3CHOZ+R1H=C2H4Z+R5CHO 2.00E+13 0 3500

593 R16C2H4OOH=C2H4Z+R3OOH 2.00E+13 0 23500 629 C2H3CHOZ+O2=B2CO+R10C2H3V+R3OOH 3.00E+13 0 36000

594 C2H5OOH=R15C2H5O+R2OH 4.00E+15 0 42900 630 H2+CN=HCN+H 1.93E+04 2.9 6.8

595 C2H5OOH+R1H=>CH3CHO+R2OH+H2 3.20E+13 0 7700 631 CH4+N=NH+CH3 1.00E+13 0 100.4

596 C2H5OOH+R4CH3=>CH3CHO+R2OH+CH4 5.70E+11 0 8700 632 CH4+CN=HCN+CH3 9.03E+04 2.6 -1.2

597 C2H5OOH+R9C2HT=>CH3CHO+R2OH+C2H2T 6.00E+11 0 9200 633 O2+N=NO+O 9.03E+09 1 27.2

598 C2H5OOH+R10C2H3V=>CH3CHO+R2OH+C2H4Z 1.00E+12 0 8700 634 O2+NH=HNO+O 3.91E+13 0 74.8

599 C2H5OOH+R11C2H5=>CH3CHO+R2OH+C2H6 3.40E+11 0 11400 635 O2+NH=NO+OH 7.59E+10 0 6.4

600 C2H5OOH+R2OH=>CH3CHO+R2OH+H2O 5.90E+12 0 900 636 O2+NH2=HNO+OH 1.51E+12 -0.4 151

601 C2H5OOH+R5CHO=>CH3CHO+R2OH+HCHO 1.80E+12 0 16700 637 O2+NH2=H2NO+O 1.10E+18 -1.3 140.6

602 C2H5OOH+R7CH3O=>CH3CHO+R2OH+CH3OH 6.30E+11 0 5500 638 O2+CN=NCO+O 7.23E+12 0 -1.7

603 C2H5OOH+R6CH2OH=>CH3CHO+R2OH+CH3OH 4.20E+11 0 13600 639 O2+NCO=NO+CO2 1.72E+07 0 -3.1

604 C2H5OOH+R14CH3CO=>2CH3CHO+R2OH 2.00E+12 0 18500 640 CO+N2O=CO2+N2 9.77E+10 0 73

605 C2H5OOH+R13CH2CHO=>2CH3CHO+R2OH 3.40E+11 0 15700 641 CO2+N=NO+CO 1.90E+11 0 14.2

606 C2H5OOH+R3OOH=>CH3CHO+R2OH+H2O2 8.00E+11 0 16200 642 N2+CH=HCN+N 1.57E+12 0 75.1

607 C2H5OOH+R8CH3OO=>CH3CHO+R2OH+CH3OOH 1.10E+12 0 16700 643 N2+CH2=HCN+NH 1.00E+13 0 309.6

608 C2H5OOH+R17C2H5OO=>CH3CHO+R2OH+C2H5OOH 1.10E+12 0 16700 644 NO+N2O=N2+NO2 1.00E+14 0 207.8

609 R18CH3COOO+C2H4O#3=CH3COOOH+R13CH2CHO 1.00E+12 0 9300 645 NO+N2H2=N2O+NH2 3.00E+12 0 0

610 R18CH3COOO+R3OOH=CH3COOOH+O2 5.50E+10 0 -2600 646 NO+C=CN+O 1.93E+13 0 0

287

Rex No Reaction A b Ea

Rex No Reaction A b Ea

647 NO+C=CO+N 2.89E+13 0 0 683 N2O+O=NO+NO 6.92E+13 0 111.4

648 NO+H=>N+OH 2.17E+14 0 207.1 684 N2O+OH=N2+HO2 6.31E+11 0 41.6

649 N+OH=>NO+H 2.83E+13 0 0 685 N2O+N=N2+NO 1.00E+13 0 83.1

650 NO+CH=CO+NH 1.20E+13 0 0 686 N2O+NH=HNO+N2 2.00E+12 0 24.9

651 NO+CH=CN+OH 1.20E+13 0 0 687 N2O+CN=NCO+N2 1.00E+13 0 0

652 NO+CH=HCN+O 9.60E+13 0 0 688 N2O+M=N2+O+M 2.86E+15 0 251

653 NO+CH2=HOCN+H 1.39E+12 0 -4.6 689 NH3+H=NH2+H2 5.42E+05 2.4 41.5

654 NO+CH2(S)=HCN+OH 9.64E+13 0 0 690 NH3+O=>NH2+OH 9.64E+12 0 30.5

655 NO+CH3=HCN+H2O 9.28E+11 0 69.9 691 NH3+OH=NH2+H2O 3.16E+12 0 8.4

656 NO+CH3=H2CN+OH 9.28E+11 0 69.9 692 NH3+HO2=NH2+H2O2 2.51E+12 0 99.8

657 NO+HO2=NO2+OH 2.09E+12 0 -2 693 NH3+NH2=N2H3+H2 7.94E+11 0.5 90.2

658 NO+HO2=HNO+O2 2.00E+11 0 8.3 694 NH3(+M)=NH2+H(+M) 8.30E+15 0 458.7

659 NO+HCCO=HOCN+CO 2.00E+13 0 0 695 NH3+M=NH+H2+M 1.80E+15 0 390.8

660 NO+N=>N2+O 4.28E+13 0 6.6 696 N2H2+H=NNH+H2 1.00E+13 0 4.2

661 N2+O=>NO+N 1.81E+14 0 318.4 697 N2H2+O=NH2+NO 1.00E+13 0 0

662 NO+NH=N2+OH 3.20E+13 0 53.2 698 N2H2+O=NNH+OH 1.00E+11 0.5 0

663 NO+NH=N2O+H 4.16E+14 -0.5 0 699 N2H2+OH=NNH+H2O 1.00E+13 0 8.3

664 NO+NH2=NNH+OH 2.41E+15 -1.2 0 700 N2H2+NH=NNH+NH2 1.00E+13 0 4.2

665 NO+NH2=N2+H2O 5.48E+15 -1.2 0 701 N2H2+NH2=NH+N2H3 1.00E+11 0.5 141.3

666 NO+NNH=N2+HNO 5.00E+13 0 0 702 N2H2+NH2=NH3+NNH 1.00E+13 0 16.6

667 NO+HNO=N2O+OH 2.95E+05 0 0 703 N2H2+M=NNH+H+M 2.50E+16 0 207.8

668 NO+NCO=N2O+CO 1.39E+18 -1.7 3.2 704 N2H2+M=NH+NH+M 7.91E+16 0 415.7

669 NO+M=N+O+M 3.62E+15 0 620.6 705 C2N2+O=NCO+CN 1.29E+14 0 59.3

670 NO2+NO2=NO+NO+O2 2.00E+12 0 112.2 706 C2N2+OH=HOCN+CN 1.87E+11 0 12

671 NO2+H=NO+OH 3.47E+14 0 6.2 707 HCN+O=NCO+H 8.45E+05 2.1 25.6

672 NO2+O=NO+O2 1.00E+13 0 2.5 708 HCN+O=NH+CO 3.19E+05 2.1 25.6

673 NO2+N=NO+NO 8.07E+11 0 0 709 HCN+O=CN+OH 2.22E+05 2.1 25.6

674 NO2+N=N2O+O 1.00E+12 0 0 710 HCN+OH=CN+H2O 9.03E+12 0 44.9

675 NO2+NH=HNO+NO 1.00E+11 0.5 16.6 711 HCN+OH=HOCN+H 5.85E+04 2.4 52.3

676 NO2+NH=N2O+OH 9.71E+12 0 0 712 HCN+OH=HNCO+H 1.98E-03 4 4.2

677 NO2+NH2=N2O+H2O 2.03E+17 -1.7 0 713 HCN+CN=C2N2+H 3.80E+07 1.6 0.4

678 NO2+CN=NCO+NO 3.00E+13 0 0 714 HOCN+H=H2O+CN 1.00E+12 0 0

679 NO2+M=NO+O+M 3.13E+16 0 274.4 715 HOCN+H=H2+NCO 1.00E+12 0 0

680 N2O+C=CN+NO 5.12E+12 0 0 716 HOCN+H=HNCO+H 1.00E+13 0 0

681 N2O+H=N2+OH 4.37E+14 0 79 717 HNCO+H=NCO+H2 2.05E+14 -0.3 84.7 682 N2O+O=N2+O2 1.00E+14 0 117.2 718 HNCO+H=NH2+CO 1.10E+14 0 53.2

288

Rex No Reaction A b Ea Rex No Reaction A b Ea

721 HNCO+O=OH+NCO 2.00E+14 0 96.4 757 OH+NH2=>O+NH3 1.99E+10 0.4 2.1

722 HNCO+OH=NCO+H2O 1.99E+12 0 23.2 758 OH+NH2=NH+H2O 5.01E+11 0.5 8.3

723 HNCO+OH=NH2+CO2 6.62E+11 0 23.2 759 OH+NNH=N2+H2O 3.16E+13 0 0

724 HNCO+HO2=NCO+H2O2 3.00E+13 0 121.3 760 OH+HNO=NO+H2O 1.08E+13 0 0

725 HNCO+N=NH+NCO 3.98E+13 0 149.7 761 OH+CN=NCO+H 6.02E+13 0 0

726 HNCO+NH=NH2+NCO 3.00E+13 0 99.2 762 OH+NCO=NO+HCO 5.00E+12 0 62.8

727 HNCO+NH2=NH3+NCO 1.00E+12 0 29.1 763 OH+NCO=NO+CO+H 1.00E+13 0 0

728 HNCO+M=NH+CO+M 2.40E+16 0 354.5 764 HO2+NH2=HNO+H2O 1.57E+13 0 0

729 HNCO+M=H+NCO+M 2.86E+17 0 468.9 765 HCCO+N=HCN+CO 5.00E+13 0 0

730 H+NH=N+H2 1.02E+13 0 0 766 N+N+M=N2+M 6.52E+15 0 0

731 H+NH2=NH+H2 6.02E+12 0 0 767 N+NH=N2+H 6.31E+11 0.5 0

732 H+NNH=N2+H2 3.98E+13 0 12.5 768 N+NH2=N2+H+H 6.93E+13 0 0

733 H+N2H3=NH2+NH2 1.58E+12 0 0 769 N+NNH=NH+N2 3.16E+13 0 8.3

734 H+N2H3=NH+NH3 1.00E+11 0 0 770 N+CN=>C+N2 1.81E+14 0 0

735 H+N2H3=N2H2+H2 1.00E+12 0 8.3 771 C+N2=>N+CN 5.24E+13 0 187.9

736 H+HNO=H2+NO 1.26E+13 0 16.6 772 N+H2CN=N2+CH2 2.00E+13 0 0

737 H+NCO=NH+CO 5.24E+13 0 0 773 N+NCO=NO+CN 2.77E+18 -1 72.2

738 CH+N=CN+H 1.26E+13 0 0 774 N+NCO=N2+CO 1.99E+13 0 0

739 CH+NH=HCN+H 5.00E+13 0 0 775 NH+NH=N2+H+H 5.13E+13 0 0

740 CH+NH2=HCN+H+H 3.00E+13 0 0 776 NH+NH2=N2H2+H 1.51E+15 -0.5 0

741 CH2+N=HCN+H 5.00E+13 0 0 777 NH+NNH=N2+NH2 2.00E+11 0.5 8.3

742 CH2+NH=HCN+H+H 3.00E+13 0 0 778 NH+M=N+H+M 7.57E+14 0 315.9

743 CH3+N=H2CN+H 2.59E+14 0 3.5 779 NH2+NH2=N2H2+H2 3.98E+13 0 49.9

744 C2H3+N=HCN+CH2 2.00E+13 0 0 780 NH2+NH2=NH3+NH 5.00E+13 0 41.8

745 O+NH=N+OH 3.72E+13 0 0 781 NH2+M=NH+H+M 7.91E+23 -2 382.4

746 O+NH=NO+H 5.50E+13 0 0 782 NH2+NNH=N2+NH3 1.00E+13 0 0

747 O+NH2=NH+OH 6.90E+11 0.3 -0.8 783 NH2+HNO=NH3+NO 5.01E+11 0.5 4.2

748 O+NH2=HNO+H 8.93E+14 -0.5 1.4 784 NNH=N2+H 3.00E+08 0 0

749 O+NNH=N2+OH 1.00E+13 0 20.8 785 NNH+M=N2+H+M 2.50E+13 0.5 12.8

750 O+NNH=N2O+H 1.00E+13 0 12.5 786 NNH+O2=N2+HO2 5.00E+12 0 0

751 O+NNH=NH+NO 1.65E+14 -0.2 -4.2 787 N2H3+M=N2H2+H+M 2.50E+16 0 207.8

752 O+HNO=OH+NO 5.01E+11 0.5 8.3 788 N2H3+M=NH2+NH+M 2.50E+16 0 174.6

753 O+CN=CO+N 1.02E+13 0 0 789 HNO+M=H+NO+M 5.09E+16 0 203.7

289

754 O+NCO=NO+CO 3.16E+13 0 0 790 H2CN+M=HCN+H+M 7.50E+14 0 92

791 NCO+M=N+CO+M 2.91E+15 0 195.4 792 H2O+CH=CH2O+H 5.72E+12 0 -3.2

290

Mechanism-III(Low Temperature, below 1000 K) Rex No Reaction A b Ea

Rex No Reaction A b Ea

1 C3H8=>R4CH3+R11C2H5 9.40E+16 0 86903.5 36 R38C4H8OOOOH=>R2OH+C3H7COOOH 3.30E+09 1 32500 2 C3H8+O2=>R3OOH+R21C3H7 1.40E+13 0 51776.7 37 R38C4H8OOOOH=>R2OH+C3H7COOOH 5.70E+08 1 25000 3 C3H8+O2=>R3OOH+R19C3H7 4.20E+13 0 54334.2 38 R38C4H8OOOOH=>R2OH+C3H7COOOH 1.50E+08 1 25000 4 R19C3H7+O2=R22C3H7OO 9.00E+18 -2.5 0 39 R25C3H6OOH=>R2OH+C3H6O#3 6.10E+11 0 17950 5 R20C4H9+O2=R23C4H9OO 9.00E+18 -2.5 0 40 R26C3H6OOH=>R2OH+C3H6O#4 9.20E+10 0 16600 6 R21C3H7+O2=R24C3H7OO 1.60E+19 -2.5 0 41 R27C4H8OOH=>R2OH+C4H8O#3 6.10E+11 0 17950 7 R25C3H6OOH+O2=R31C3H6OOOOH 1.70E+19 -2.5 0 42 R28C4H8OOH=>R2OH+C4H8O#4 9.20E+10 0 16600 8 R26C3H6OOH+O2=R32C3H6OOOOH 9.00E+18 -2.5 0 43 R29C4H8OOH=>R2OH+C4H8O#5 3.60E+09 0 7000 9 R27C4H8OOH+O2=R33C4H8OOOOH 1.80E+19 -2.5 0 44 R30C3H6OOH=>R2OH+C3H6O#3 6.10E+11 0 17950

10 R28C4H8OOH+O2=R34C4H8OOOOH 1.70E+19 -2.5 0 45 R19C3H7+O2=>C3H6Y+R3OOH 2.80E+12 0 5000 11 R29C4H8OOH+O2=R35C4H8OOOOH 9.00E+18 -2.5 0 46 R21C3H7+O2=>C3H6Y+R3OOH 2.30E+12 0 5000 12 R30C3H6OOH+O2=R37C3H6OOOOH 1.50E+18 -2.5 0 47 B1O+C3H8=>R2OH+R21C3H7 2.60E+13 0 5200 13 R36C4H8OOH+O2=R38C4H8OOOOH 1.00E+19 -2.5 0 48 B1O+C3H8=>R2OH+R19C3H7 1.00E+14 0 7850 14 R22C3H7OO=R25C3H6OOH 3.30E+09 1 32500 49 C3H8+R1H=>H2+R21C3H7 9.00E+06 2 5000 15 R22C3H7OO=R26C3H6OOH 8.60E+08 1 28000 50 C3H8+R1H=>H2+R19C3H7 5.70E+07 2 7700 16 R23C4H9OO=R27C4H8OOH 3.30E+09 1 32500 51 C3H8+R2OH=>H2O+R21C3H7 2.60E+06 2 -765 17 R23C4H9OO=R28C4H8OOH 5.70E+08 1 25000 52 C3H8+R2OH=>H2O+R19C3H7 5.40E+06 2 450 18 R23C4H9OO=R29C4H8OOH 1.50E+08 1 25000 53 C3H8+R3OOH=>H2O2+R21C3H7 4.00E+11 0 15500 19 R24C3H7OO=R30C3H6OOH 1.00E+10 1 35500 54 C3H8+R3OOH=>H2O2+R19C3H7 1.20E+12 0 17000 20 R29C4H8OOH=R36C4H8OOH 5.70E+08 1 15300 55 C3H8+R4CH3=>CH4+R21C3H7 2.00E+11 0 9600 21 R31C3H6OOOOH=>R2OH+C2H5COOOH 5.00E+09 1 35500 56 C3H8+R4CH3=>CH4+R19C3H7 6.00E-01 4 8200 22 R31C3H6OOOOH=>R2OH+C2H5COOOH 3.30E+09 1 30500 57 C3H8+R5CHO=>HCHO+R21C3H7 1.00E+07 1.9 17000 23 R32C3H6OOOOH=>R2OH+C2H5COOOH 3.30E+09 1 32500 58 C3H8+R5CHO=>HCHO+R19C3H7 2.00E+05 2.5 18500 24 R32C3H6OOOOH=>R2OH+C2H5COOOH 5.70E+08 1 23000 59 C3H8+R6CH2OH=>CH3OH+R21C3H7 6.00E+01 3 12000 25 R33C4H8OOOOH=>R2OH+C3H7COOOH 3.30E+09 1 30500 60 C3H8+R6CH2OH=>CH3OH+R19C3H7 2.00E+02 3 14000 26 R33C4H8OOOOH=>R2OH+C3H7COOOH 3.30E+09 1 32500 61 C3H8+R7CH3O=>CH3OH+R21C3H7 1.50E+11 0 4500 27 R33C4H8OOOOH=>R2OH+C3H7COOOH 8.60E+08 1 28000 62 C3H8+R7CH3O=>CH3OH+R19C3H7 3.20E+11 0 7300 28 R34C4H8OOOOH=>R2OH+C3H7COOOH 5.00E+09 1 35500 63 C3H8+R8CH3OO=>CH3OOH+R21C3H7 3.00E+12 0 17500 29 R34C4H8OOOOH=>R2OH+C3H7COOOH 3.30E+09 1 32500 64 C3H8+R8CH3OO=>CH3OOH+R19C3H7 1.20E+13 0 20000 30 R34C4H8OOOOH=>R2OH+C3H7COOOH 5.70E+08 1 23000 65 C3H8+R11C2H5=>C2H6+R21C3H7 2.00E+11 0 11000 31 R35C4H8OOOOH=>R2OH+C3H7COOOH 5.70E+08 1 32500 66 C3H8+R11C2H5=>C2H6+R19C3H7 6.00E+11 0 13500 32 R35C4H8OOOOH=>R2OH+C3H7COOOH 5.70E+08 1 25000 67 C3H8+R21C3H7=>C3H8+R19C3H7 8.40E-03 4.2 8700 33 R35C4H8OOOOH=>R2OH+C3H7COOOH 9.90E+07 1 20000 68 C3H8+R22C3H7OO=>C3H7OOH+R21C3H7 3.00E+12 0 17500 34 R37C3H6OOOOH=>R2OH+C2H5COOOH 1.70E+09 1 27500 69 C3H8+R22C3H7OO=>C3H7OOH+R19C3H7 1.20E+13 0 20000 35 R37C3H6OOOOH=>R2OH+C2H5COOOH 8.60E+08 1 28000 70 C3H8+R24C3H7OO=>C3H7OOH+R21C3H7 3.00E+12 0 17500

291

Rex No Reaction A b Ea

Rex No Reaction A b Ea

71 C3H8+R24C3H7OO=>C3H7OOH+R19C3H7 1.20E+13 0 20000 106 C6H14+R4CH3=>CH4+R11C2H5+2C2H4Z 6.00E+11 0 9600

72 R1H+R21C3H7=>C3H8 8.30E+12 0 0 107 C6H14+R8CH3OO=>CH3OOH+R11C2H5+2C2H4Z 4.50E+12 0 17500

73 R2OH+R21C3H7=>C3H7OH 5.90E+12 0 0 108 C6H14+R11C2H5=>C2H6+R11C2H5+2C2H4Z 6.00E+11 0 11000

74 R3OOH+R21C3H7=>C3H7OOH 4.80E+12 0 0 109 C3H6O#3+R1H=>H2+CH2COZ+R4CH3 2.70E+07 2 5000

75 R4CH3+R21C3H7=>C4H10 1.50E+13 0 0 110 C3H6O#3+R2OH=>H2O+CH2COZ+R4CH3 7.80E+06 2 -765

76 R5CHO+R21C3H7=>C3H7CHO 5.20E+12 0 0 111 C3H6O#3+R3OOH=>H2O2+CH2COZ+R4CH3 1.20E+12 0 15500

77 R6CH2OH+R21C3H7=>C4H9OH 5.10E+12 0 0 112 C3H6O#3+R4CH3=>CH4+CH2COZ+R4CH3 6.00E+11 0 9600

78 R7CH3O+R21C3H7=>C4H10O 4.90E+12 0 0 113 C3H6O#3+R8CH3OO=>CH3OOH+CH2COZ+R4CH3 6.00E+11 0 9600

79 R8CH3OO+R21C3H7=>C4H10OO 4.40E+12 0 0 114 C3H6O#3+R11C2H5=>C2H6+CH2COZ+R4CH3 6.00E+11 0 11000

80 R11C2H5+R21C3H7=>C5H12 5.20E+12 0 0 115 C4H8O#3+R1H=>H2+CH2COZ+R11C2H5 2.70E+07 2 5000

81 R21C3H7+R21C3H7=>C6H14 2.30E+12 0 0 116 C4H8O#3+R2OH=>H2O+CH2COZ+R11C2H5 7.80E+06 2 -765

82 R22C3H7OO+R3OOH=>C3H7OOH+O2 2.00E+11 0 -1300 117 C4H8O#3+R3OOH=>H2O2+CH2COZ+R11C2H5 1.20E+12 0 15500

83 R23C4H9OO+R3OOH=>C4H9OOH+O2 2.00E+11 0 -1300 118 C4H8O#3+R4CH3=>CH4+CH2COZ+R11C2H5 6.00E+11 0 9600

84 R24C3H7OO+R3OOH=>C3H7OOH+O2 2.00E+11 0 -1300 119 C4H8O#3+R8CH3OO=>CH3OOH+CH2COZ+R11C2H5 6.00E+11 0 9600

85 C3H7OOH=>R2OH+HCHO+R11C2H5 1.50E+16 0 42000 120 C4H8O#3+R11C2H5=>C2H6+CH2COZ+R11C2H5 6.00E+11 0 11000

86 C4H9OOH=>R2OH+CH3CHO+R11C2H5 1.50E+16 0 42000 121 C4H8O#4+R1H=>H2+R13CH2CHO+C2H4Z 2.70E+07 2 5000

87 C3H5OOHY=>R2OH+HCHO+R10C2H3V 1.50E+16 0 42000 122 C4H8O#4+R2OH=>H2O+R13CH2CHO+C2H4Z 7.80E+06 2 -765

88 C4H7OOHY=>R2OH+CH3CHO+R10C2H3V 1.50E+16 0 42000 123 C4H8O#4+R3OOH=>H2O2+R13CH2CHO+C2H4Z 1.20E+12 0 15500

89 C2H5COOOH=>R2OH+HCHO+B2CO+R4CH3 1.50E+16 0 42000 124 C4H8O#4+R4CH3=>CH4+R13CH2CHO+C2H4Z 6.00E+11 0 9600

90 C3H7COOOH=>R2OH+HCHO+B2CO+R11C2H5 1.50E+16 0 42000 125 C4H8O#4+R8CH3OO=>CH3OOH+R13CH2CHO+C2H4Z 4.50E+12 0 17500

91 C4H10+R1H=>H2+R11C2H5+C2H4Z 2.70E+07 2 5000 126 C4H8O#4+R11C2H5=>C2H6+R13CH2CHO+C2H4Z 6.00E+11 0 11000

92 C4H10+R2OH=>H2O+R11C2H5+C2H4Z 7.80E+06 2 -765 127 C4H8O#5+R1H=>H2+R13CH2CHO+C2H4Z 2.70E+07 2 5000

93 C4H10+R3OOH=>H2O2+R11C2H5+C2H4Z 1.20E+12 0 15500 128 C4H8O#5+R2OH=>H2O+R13CH2CHO+C2H4Z 7.80E+06 2 -765

94 C4H10+R4CH3=>CH4+R11C2H5+C2H4Z 6.00E+11 0 9600 129 C4H8O#5+R3OOH=>H2O2+R13CH2CHO+C2H4Z 1.20E+12 0 15500

95 C4H10+R8CH3OO=>CH3OOH+R11C2H5+C2H4Z 4.50E+12 0 17500 130 C4H8O#5+R4CH3=>CH4+R13CH2CHO+C2H4Z 6.00E+11 0 9600

96 C4H10+R11C2H5=>C2H6+R11C2H5+C2H4Z 6.00E+11 0 11000 131 C4H8O#5+R8CH3OO=>CH3OOH+R13CH2CHO+C2H4Z 4.50E+12 0 17500

97 C5H12+R1H=>H2+R4CH3+2C2H4Z 2.70E+07 2 5000 132 C4H8O#5+R11C2H5=>C2H6+R13CH2CHO+C2H4Z 6.00E+11 0 11000

98 C5H12+R2OH=>H2O+R4CH3+2C2H4Z 7.80E+06 2 -765 133 C3H6O#3+B1O=>R2OH+R5CHO+C2H4Z 7.80E+13 0 5200

99 C5H12+R3OOH=>H2O2+R4CH3+2C2H4Z 1.20E+12 0 15500 134 C4H8O#3+B1O=>R2OH+R13CH2CHO+C2H4Z 7.80E+13 0 5200

100 C5H12+R4CH3=>CH4+R4CH3+2C2H4Z 6.00E+11 0 9600 135 C4H8O#4+B1O=>R2OH+R13CH2CHO+C2H4Z 7.80E+13 0 5200

101 C5H12+R8CH3OO=>CH3OOH+R4CH3+2C2H4Z 4.50E+12 0 17500 136 C4H8O#5+B1O=>R2OH+R13CH2CHO+C2H4Z 7.80E+13 0 5200

102 C5H12+R11C2H5=>C2H6+R4CH3+2C2H4Z 6.00E+11 0 11000 137 C3H6O#4+R1H=>H2+.C3H5O#4 2.70E+07 2 5000

103 C6H14+R1H=>H2+R11C2H5+2C2H4Z 2.70E+07 2 5000 138 C3H6O#4+R2OH=>H2O+.C3H5O#4 7.80E+06 2 -765

104 C6H14+R2OH=>H2O+R11C2H5+2C2H4Z 7.80E+06 2 -765 139 C3H6O#4+R3OOH=>H2O2+.C3H5O#4 1.20E+12 0 15500

105 C6H14+R3OOH=>H2O2+R11C2H5+2C2H4Z 1.20E+12 0 15500 140 C3H6O#4+R4CH3=>CH4+.C3H5O#4 6.00E+11 0 9600

292

Rex No Reaction A b Ea

Rex No Reaction A b Ea

141 C3H6O#4+R8CH3OO=>CH3OOH+.C3H5O#4 6.00E+11 0 9600 177 .C3H5Y+C3H6Y=>R10C2H3V+2C2H4Z 6.00E+09 0 11400

142 C3H6O#4+R11C2H5=>C2H6+.C3H5O#4 6.00E+11 0 11000 178 .C4H7Y+C4H8Y=>R10C2H3V+3C2H4Z 6.00E+09 0 11400

143 .C3H5O#4=>R5CHO+C2H4Z 5.00E+13 0 28800 179 .C4H7Y+C3H6Y=>R4CH3+C2H2T+2C2H4Z 6.00E+09 0 11400

144 .C3H5O#4+O2=>.OOC3H5O#4 3.00E+19 -2.5 0 180 C3H7OH+R1H=>H2+R2OH+C3H6Y 9.00E+06 2 5000

145 .OOC3H5O#4=>.C3H5O#4+O2 5.00E+22 -2.5 40000 181 C3H7OH+R2OH=>H2O+R2OH+C3H6Y 1.30E+06 2 -765

146 .OOC3H5O#4=>.C3H4O#4OOH 8.00E+13 0 25500 182 C3H7OH+R3OOH=>H2O2+R2OH+C3H6Y 4.00E+11 0 15500

147 .C3H4O#4OOH=>.OOC3H5O#4 4.80E+12 0 19000 183 C3H7OH+R4CH3=>CH4+R2OH+C3H6Y 2.00E+11 0 9600

148 .C3H4O#4OOH+O2=>.OOC3H4O#4OOH 3.00E+19 -2.5 0 184 C3H7OH+R8CH3OO=>CH3OOH+R2OH+C3H6Y 3.00E+12 0 17500

149 .OOC3H4O#4OOH=>.C3H4O#4OOH+O2 5.00E+22 -2.5 40000 185 C3H7OH+R11C2H5=>C2H6+R2OH+C3H6Y 2.00E+11 0 11000

150 .OOC3H4O#4OOH=>R2OH+C2H3O#4COOOH 1.00E+09 0 7500 186 C4H9OH+R1H=>H2+R2OH+C4H8Y 9.00E+06 2 5000

151 C2H3O#4COOOH=>R2OH+CO2+R13CH2CHO 1.50E+16 0 42000 187 C4H9OH+R1H=>H2+R4CH3+C2H6CO 4.20E+06 2 2400

152 C3H6Y+R1H=>C2H4Z+R4CH3 7.20E+12 0 2900 188 C4H9OH+R2OH=>H2O+R2OH+C4H8Y 1.30E+06 2 -765

153 C4H8Y+R1H=>C2H4Z+R11C2H5 7.20E+12 0 2900 189 C4H9OH+R2OH=>H2O+R4CH3+C2H6CO 4.00E+12 0 443

154 C3H6Y+R2OH=>R4CH3+CH3CHO 1.40E+12 0 -900 190 C4H9OH+R3OOH=>H2O2+R2OH+C4H8Y 4.00E+11 0 15500

155 C4H8Y+R2OH=>R4CH3+C2H5CHO 1.40E+12 0 -900 191 C4H9OH+R3OOH=>H2O2+R4CH3+C2H6CO 1.00E+12 0 14000

156 C3H6Y+R2OH=>HCHO+R11C2H5 1.40E+12 0 -900 192 C4H9OH+R4CH3=>CH4+R2OH+C4H8Y 2.00E+11 0 9600

157 C4H8Y+R2OH=>HCHO+R4CH3+C2H4Z 1.40E+12 0 -900 193 C4H9OH+R4CH3=>CH4+R4CH3+C2H6CO 1.00E+11 0 7600

158 C3H6Y+B1O=>CH2COZ+R4CH3+R1H 3.40E+07 1.8 550 194 C4H9OH+R8CH3OO=>CH3OOH+R2OH+C4H8Y 3.00E+12 0 17500

159 C4H8Y+B1O=>CH2COZ+R11C2H5+R1H 3.40E+07 1.8 550 195 C4H9OH+R11C2H5=>C2H6+R2OH+C4H8Y 2.00E+11 0 11000

160 C3H6Y+R3OOH=>R2OH+C3H6O#3 1.00E+12 0 14400 196 C4H9OH+R11C2H5=>C2H6+R4CH3+C2H6CO 1.00E+11 0 9200

161 C4H8Y+R3OOH=>R2OH+C4H8O#3 1.00E+12 0 14400 197 C3H7OH+B1O=>R2OH+R2OH+C3H6Y 9.00E+06 2 5000

162 C3H6Y+R1H=>.C3H5Y+H2 5.70E+04 2.5 290 198 C4H9OH+B1O=>R2OH+R2OH+C4H8Y 9.00E+06 2 5000

163 C3H6Y+R2OH=>.C3H5Y+H2O 3.00E+06 2 -1515 199 C4H9OH+B1O=>R2OH+R4CH3+C2H6CO 4.20E+06 2 2400

164 C3H6Y+R3OOH=>.C3H5Y+H2O2 6.30E+03 2.6 12400 200 C2H5CHO+R1H=>H2+.COC2H5 4.00E+13 0 4200

165 C3H6Y+R4CH3=>.C3H5Y+CH4 1.30E+00 3.5 3575 201 C2H5CHO+R2OH=>H2O+.COC2H5 4.20E+12 0 500

166 C3H6Y+R8CH3OO=>.C3H5Y+CH3OOH 2.00E+12 0 17050 202 C2H5CHO+R3OOH=>H2O2+.COC2H5 1.00E+12 0 10000

167 C3H6Y+R11C2H5=>.C3H5Y+C2H6 1.40E+00 3.5 4335 203 C2H5CHO+R4CH3=>CH4+.COC2H5 2.00E-06 5.6 2500

168 C4H8Y+R1H=>.C4H7Y+H2 5.70E+04 2.5 290 204 C2H5CHO+R11C2H5=>C2H6+.COC2H5 1.30E+12 0 8500

169 C4H8Y+R2OH=>.C4H7Y+H2O 3.00E+06 2 -1515 205 C2H3CHOZ+R1H=>H2+.COC2H3Z 4.00E+13 0 4200

170 C4H8Y+R3OOH=>.C4H7Y+H2O2 6.30E+03 2.6 12400 206 C2H3CHOZ+R2OH=>H2O+.COC2H3Z 4.20E+12 0 500

171 C4H8Y+R4CH3=>.C4H7Y+CH4 1.30E+00 3.5 3575 207 C2H3CHOZ+R3OOH=>H2O2+.COC2H3Z 1.00E+12 0 10000

172 C4H8Y+R8CH3OO=>.C4H7Y+CH3OOH 2.00E+12 0 17050 208 C2H3CHOZ+R4CH3=>CH4+.COC2H3Z 2.00E-06 5.6 2500

173 C4H8Y+R11C2H5=>.C4H7Y+C2H6 1.40E+00 3.5 4335 209 C2H3CHOZ+R11C2H5=>C2H6+.COC2H3Z 1.30E+12 0 8500

174 C3H6Y+B1O=>.C3H5Y+R2OH 9.10E+10 0.7 3830 210 C3H7CHO+R1H=>H2+.COC3H7 4.00E+13 0 4200

175 C4H8Y+B1O=>.C4H7Y+R2OH 9.10E+10 0.7 3830 211 C3H7CHO+R2OH=>H2O+.COC3H7 4.20E+12 0 500

176 .C3H5Y+C4H8Y=>R4CH3+C2H2T+2C2H4Z 6.00E+09 0 11400 212 C3H7CHO+R3OOH=>H2O2+.COC3H7 1.00E+12 0 10000

293

Rex No Reaction A b Ea

Rex No Reaction A b Ea

213 C3H7CHO+R4CH3=>CH4+.COC3H7 2.00E-06 5.6 2500 249 .C4H7Y+R11C2H5=>C6H12Y 1.00E+13 0 0

214 C3H7CHO+R11C2H5=>C2H6+.COC3H7 1.30E+12 0 8500 250 .C3H5Y+.C3H5Y=>C6H10Y2 1.00E+13 0 0

215 .COC2H5=>B2CO+R11C2H5 2.00E+13 0 28700 251 .C3H5Y+.C4H7Y=>C7H12Y2 1.00E+13 0 0

216 .COC3H7=>B2CO+R4CH3+C2H4Z 2.00E+13 0 28700 252 .C4H7Y+.C4H7Y=>C8H14Y2 1.00E+13 0 0

217 .COC2H5+O2=>.COOOC2H5 3.00E+19 -2.5 0 253 R1H+R1H+M=H2+M 1.87E+18 -1 0

218 .COC3H7+O2=>.COOOC3H7 3.00E+19 -2.5 0 254 B4CH+R1H=B3C+H2 7.80E+13 0 0

219 .COOOC2H5=>C2H4Z+R2OH+CO2 4.50E+11 0 25000 255 B6CH2+M=B5CH2+M 1.51E+13 0 0

220 .COOOC3H7=>C3H6Y+R2OH+CO2 4.50E+11 0 25000 256 B6CH2+R1H=B4CH+H2 3.00E+13 0 0

221 C2H6CO+R1H=>H2+CH2COZ+R4CH3 2.70E+07 2 5000 257 B5CH2+R1H=B4CH+H2 6.00E+12 0 -1800

222 C2H6CO+R2OH=>H2O+CH2COZ+R4CH3 7.80E+06 2 -765 258 B5CH2+B3C=R9C2HT+R1H 5.00E+13 0 0

223 C2H6CO+R3OOH=>H2O2+CH2COZ+R4CH3 1.20E+12 0 15500 259 B5CH2+B5CH2=>C2H2T+R1H+R1H 1.20E+14 0 800

224 C2H6CO+R4CH3=>CH4+CH2COZ+R4CH3 6.00E+11 0 9600 260 R4CH3+M=B5CH2+R1H+M 2.91E+16 0 90700

225 C2H6CO+R8CH3OO=>CH3OOH+CH2COZ+R4CH3 6.00E+11 0 9600 261 R4CH3+R1H=B6CH2+H2 6.00E+13 0 15000

226 C2H6CO+R11C2H5=>C2H6+CH2COZ+R4CH3 6.00E+11 0 11000 262 R4CH3+B4CH=R10C2H3V+R1H 3.00E+13 0 0

227 C3H8CO+R1H=>H2+CH2COZ+R11C2H5 2.70E+07 2 5000 263 R4CH3+B6CH2=C2H4Z+R1H 1.80E+13 0 0

228 C3H8CO+R2OH=>H2O+CH2COZ+R11C2H5 7.80E+06 2 -765 264 R4CH3+B5CH2=C2H4Z+R1H 4.20E+13 0 0

229 C3H8CO+R3OOH=>H2O2+CH2COZ+R11C2H5 1.20E+12 0 15500 265 R4CH3+B3C=C2H2T+R1H 5.00E+13 0 0

230 C3H8CO+R4CH3=>CH4+CH2COZ+R11C2H5 6.00E+11 0 9600 266 R4CH3+R4CH3(+M)=>C2H6(+M) 3.61E+13 0 0

231 C3H8CO+R8CH3OO=>CH3OOH+CH2COZ+R11C2H5 6.00E+11 0 9600 267 C2H6(+M)=>R4CH3+R4CH3(+M) 1.80E+21 -1 90900

232 C3H8CO+R11C2H5=>C2H6+CH2COZ+R11C2H5 6.00E+11 0 11000 268 R4CH3+R4CH3=R11C2H5+R1H 3.00E+13 0 13500

233 C4H6Z2+C2H4Z=>C6H10Z#6 3.00E+10 0 27500 269 R4CH3+R4CH3=C2H4Z+H2 2.10E+14 0 19300

234 .C3H5Y+R1H=>C3H6Y 1.00E+13 0 0 270 R1H+R4CH3(+M)=>CH4(+M) 1.67E+14 0 0

235 .C3H5Y+R2OH=>C3H5OHY 1.00E+13 0 0 271 CH4(+M)=>R4CH3+R1H(+M) 2.40E+16 0 105000

236 .C3H5Y+R3OOH=>C3H5OOHY 5.00E+12 0 0 272 CH4(+CH4)=>R4CH3+R1H(+CH4) 2.40E+16 0 105000

237 .C3H5Y+R4CH3=>C4H8Y 1.00E+13 0 0 273 CH4+R1H=R4CH3+H2 1.30E+04 3 8000

238 .C3H5Y+R5CHO=>C3H5CHOY 1.00E+13 0 0 274 CH4+B4CH=C2H4Z+R1H 3.00E+13 0 -400

239 .C3H5Y+R6CH2OH=>C4H7OHY 1.00E+13 0 0 275 CH4+B6CH2=R4CH3+R4CH3 4.20E+13 0 0

240 .C3H5Y+R8CH3OO=>C4H8OOY 1.00E+13 0 0 276 R9C2HT+B6CH2=C2H2T+B4CH 1.80E+13 0 0

241 .C3H5Y+R11C2H5=>C5H10Y 1.00E+13 0 0 277 R9C2HT+B5CH2=C2H2T+B4CH 1.80E+13 0 0

242 .C4H7Y+R1H=>C4H8Y 1.00E+13 0 0 278 R9C2HT+CH4=C2H2T+R4CH3 1.20E+12 0 0

243 .C4H7Y+R2OH=>C4H7OHY 1.00E+13 0 0 279 C2H2T+M=R9C2HT+R1H+M 1.14E+17 0 107000

244 .C4H7Y+R3OOH=>C4H7OOHY 5.00E+12 0 0 280 C2H2T+R1H=R9C2HT+H2 6.60E+13 0 27700

245 .C4H7Y+R4CH3=>C5H10Y 1.00E+13 0 0 281 R10C2H3V(+M)=C2H2T+R1H(+M) 2.00E+14 0 39800

246 .C4H7Y+R5CHO=>C4H7CHOY 1.00E+13 0 0 282 R10C2H3V+R1H=C2H2T+H2 1.20E+13 0 0

247 .C4H7Y+R6CH2OH=>C5H9OHY 1.00E+13 0 0 283 R10C2H3V+B6CH2=C2H2T+R4CH3 1.80E+13 0 0

248 .C4H7Y+R8CH3OO=>C5H10OOY 1.00E+13 0 0 284 R10C2H3V+B5CH2=C2H2T+R4CH3 1.80E+13 0 0

294

Rex No Reaction A b Ea

Rex No Reaction A b Ea

285 R10C2H3V+R4CH3=CH4+C2H2T 3.90E+11 0 0 321 B1O+R10C2H3V=R4CH3+B2CO 3.00E+13 0 0

286 R10C2H3V+R9C2HT=2C2H2T 9.60E+11 0 0 322 B1O+R10C2H3V=CH2COZ+R1H 9.60E+13 0 0

287 R10C2H3V+R10C2H3V=C2H4Z+C2H2T 9.60E+11 0 0 323 B1O+C2H4Z=R4CH3+R5CHO 8.10E+06 1.9 200

288 C2H4Z+M=C2H2T+H2+M 9.97E+16 0 71600 324 B1O+C2H4Z=HCHO+B5CH2 4.00E+05 1.9 200

289 C2H4Z+M=R10C2H3V+R1H+M 7.40E+17 0 96700 325 B1O+C2H4Z=CH2COZ+H2 6.60E+05 1.9 200

290 C2H4Z+R1H=R10C2H3V+H2 5.00E+07 1.9 13000 326 B1O+C2H4Z=R13CH2CHO+R1H 4.70E+06 1.9 200

291 C2H4Z+R4CH3=CH4+R10C2H3V 6.30E+11 0 16000 327 B1O+C2H4Z=R2OH+R10C2H3V 1.50E+07 1.9 3700

292 R11C2H5(+M)=C2H4Z+R1H(+M) 8.20E+13 0 40000 328 B1O+R11C2H5=HCHO+R4CH3 1.10E+13 0 0

293 R11C2H5+R1H=C2H4Z+H2 1.80E+12 0 0 329 B1O+R11C2H5=CH3CHO+R1H 5.50E+13 0 0

294 R11C2H5+R1H=C2H6 3.60E+13 0 0 330 B1O+R11C2H5=C2H4Z+R2OH 3.00E+13 0 0

295 R11C2H5+B6CH2=C2H4Z+R4CH3 9.00E+12 0 0 331 B1O+C2H6=R11C2H5+R2OH 1.00E+09 1.5 5800

296 R11C2H5+B5CH2=C2H4Z+R4CH3 1.80E+13 0 0 332 R1H+B1O+M=R2OH+M 1.18E+19 -1 0

297 R11C2H5+R4CH3=C2H4Z+CH4 1.10E+12 0 0 333 R1H+R2OH+M=H2O+M 5.53E+22 -2 0

298 R11C2H5+R9C2HT=C2H2T+C2H4Z 1.80E+12 0 0 334 R2OH+H2=R1H+H2O 1.00E+08 1.6 3300

299 R11C2H5+R10C2H3V=2C2H4Z 4.80E+11 0 0 335 R2OH+B3C=B2CO+R1H 5.00E+13 0 0

300 R11C2H5+R10C2H3V=C2H2T+C2H6 4.80E+11 0 0 336 R2OH+B4CH=R5CHO+R1H 3.00E+13 0 0

301 R11C2H5+R11C2H5=C2H4Z+C2H6 1.40E+12 0 0 337 R2OH+B6CH2=HCHO+R1H 3.00E+13 0 0

302 C2H6+M=C2H4Z+H2+M 2.30E+17 0 67400 338 R2OH+B5CH2=HCHO+R1H 1.80E+13 0 0

303 C2H6+R1H=R11C2H5+H2 1.40E+09 1.5 7400 339 R2OH+R4CH3=B6CH2+H2O 7.20E+13 0 2700

304 C2H6+B6CH2=R4CH3+R11C2H5 1.10E+14 0 0 340 R2OH+R4CH3(+M)=CH3OH(+M) 6.00E+13 0 0

305 C2H6+R4CH3=R11C2H5+CH4 1.50E-07 6 5800 341 R2OH+R4CH3=HCHO+H2 3.20E+12 -1 10800

306 C2H6+R9C2HT=C2H2T+R11C2H5 3.60E+12 0 0 342 R2OH+R4CH3=R7CH3O+R1H 5.70E+12 -0 13900

307 C2H6+R10C2H3V=R11C2H5+C2H4Z 6.00E+02 3.3 10500 343 R2OH+CH4=R4CH3+H2O 1.60E+07 1.8 2700

308 B1O+H2=R2OH+R1H 5.10E+04 2.7 6200 344 R2OH+R9C2HT=C2H2T+B1O 1.80E+13 0 0

309 B1O+B4CH=B2CO+R1H 3.90E+13 0 0 345 R2OH+R9C2HT=B5CH2+B2CO 1.80E+13 0 0

310 B1O+B4CH=B3C+R2OH 1.50E+13 0 4700 346 R2OH+R9C2HT=R12CHCOV+R1H 2.00E+13 0 0

311 B1O+B6CH2=>B2CO+2R1H 1.50E+13 0 0 347 R2OH+C2H2T=R9C2HT+H2O 1.40E+04 2.7 12000

312 B1O+B6CH2=B2CO+H2 1.50E+13 0 0 348 R2OH+C2H2T=CH2COZ+R1H 2.20E-04 4.5 -1000

313 B1O+B5CH2=>B2CO+2R1H 7.20E+13 0 0 349 R2OH+C2H2T=R4CH3+B2CO 4.80E-04 4 -2000

314 B1O+B5CH2=B2CO+H2 4.80E+13 0 0 350 R2OH+R10C2H3V=C2H2T+H2O 3.00E+13 0 0

315 B1O+R4CH3=HCHO+R1H 8.40E+13 0 0 351 R2OH+R10C2H3V=CH3CHO 3.00E+13 0 0

316 B1O+R4CH3=R7CH3O 8.00E+15 -2.1 600 352 R2OH+C2H4Z=R10C2H3V+H2O 2.00E+13 0 5900

317 B1O+CH4=R4CH3+R2OH 7.20E+08 1.6 8400 353 R2OH+C2H4Z=R4CH3+HCHO 2.00E+12 0 900

318 B1O+R9C2HT=B4CH+B2CO 1.00E+13 0 0 354 R2OH+R11C2H5=C2H4Z+H2O 2.40E+13 0 0

319 B1O+C2H2T=B5CH2+B2CO 2.17E+06 2.1 1600 355 R2OH+R11C2H5=>R4CH3+R1H+HCHO 2.40E+13 0 0

320 B1O+C2H2T=R12CHCOV+R1H 5.06E+06 2.1 1600 356 R2OH+C2H6=R11C2H5+H2O 7.20E+06 2 900

295

Rex No Reaction A b Ea

Rex No Reaction A b Ea

357 R2OH+R2OH=H2O+B1O 1.50E+09 1.1 100 393 R7CH3O+R9C2HT=HCHO+C2H2T 2.40E+13 0 0

358 H2O+B4CH=R6CH2OH 5.70E+12 0 -800 394 R7CH3O+R10C2H3V=HCHO+C2H4Z 2.40E+13 0 0

359 H2O+B6CH2=CH3OH 1.80E+13 0 0 395 R7CH3O+C2H4Z=HCHO+R11C2H5 1.20E+11 0 6700

360 B2CO+R4CH3(+M)=R14CH3CO(+M) 5.00E+11 0 6900 396 R7CH3O+R11C2H5=HCHO+C2H6 2.40E+13 0 0

361 B2CO+B1O+M=CO2+M 1.54E+15 0 3000 397 R7CH3O+C2H6=R11C2H5+CH3OH 2.40E+11 0 7000

362 B2CO+R2OH=CO2+R1H 6.30E+06 1.5 -500 398 R7CH3O+B1O=HCHO+R2OH 1.80E+12 0 0

363 R5CHO+M=R1H+B2CO+M 1.90E+17 -1 17000 399 R7CH3O+R2OH=HCHO+H2O 1.80E+13 0 0

364 R5CHO+R1H=H2+B2CO 9.00E+13 0 0 400 R7CH3O+B2CO=R4CH3+CO2 1.60E+13 0 11700

365 R5CHO+R1H=B1O+B5CH2 4.00E+13 0 102500 401 R7CH3O+R5CHO=CH3OH+B2CO 9.10E+13 0 0

366 R5CHO+B6CH2=R4CH3+B2CO 1.80E+13 0 0 402 R7CH3O+HCHO=CH3OH+R5CHO 1.00E+11 0 3000

367 R5CHO+B5CH2=R4CH3+B2CO 1.80E+13 0 0 403 R7CH3O+R7CH3O=CH3OH+HCHO 6.00E+13 0 0

368 R5CHO+R4CH3=CH4+B2CO 1.20E+14 0 0 404 R6CH2OH+M=HCHO+R1H+M 1.26E+16 0 30000

369 R5CHO+R4CH3=CH3CHO 1.80E+13 0 0 405 R6CH2OH+R1H=R4CH3+R2OH 9.60E+13 0 0

370 R4CH3+HCHO=R5CHO+CH4 7.70E-08 6.1 1970 406 R6CH2OH+R1H=HCHO+H2 6.00E+12 0 0

371 R5CHO+R9C2HT=C2H2T+B2CO 6.00E+13 0 0 407 R6CH2OH+H2=CH3OH+R1H 6.70E+05 2 13400

372 R5CHO+R10C2H3V=C2H4Z+B2CO 9.00E+13 0 0 408 R6CH2OH+B6CH2=CH3CHO+R1H 1.80E+13 0 0

373 R10C2H3V+HCHO=R5CHO+C2H4Z 5.40E+03 2.8 5900 409 R6CH2OH+B5CH2=C2H4Z+R2OH 2.40E+13 0 0

374 R5CHO+R11C2H5=C2H6+B2CO 1.20E+14 0 0 410 R6CH2OH+B5CH2=R4CH3+HCHO 1.20E+12 0 0

375 R11C2H5+HCHO=R5CHO+C2H6 5.57E+03 2.8 5860 411 R6CH2OH+R4CH3=C2H5OH 1.20E+13 0 0

376 R5CHO+B1O=R1H+CO2 3.00E+13 0 0 412 R6CH2OH+R4CH3=CH4+HCHO 2.40E+12 0 0

377 R5CHO+B1O=R2OH+B2CO 3.00E+13 0 0 413 R6CH2OH+CH4=CH3OH+R4CH3 2.17E+01 3.1 16200

378 R5CHO+R2OH=H2O+B2CO 1.10E+14 0 0 414 R6CH2OH+R9C2HT=C2H2T+HCHO 4.80E+13 0 0

379 R5CHO+R5CHO=HCHO+B2CO 3.00E+13 0 0 415 R6CH2OH+C2H2T=R10C2H3V+HCHO 7.20E+11 0 9000

380 HCHO+M=R5CHO+R1H+M 1.40E+36 -5.5 96800 416 R6CH2OH+R10C2H3V=C2H4Z+HCHO 4.20E+13 0 0

381 HCHO+M=H2+B2CO+M 3.26E+36 -5.5 96800 417 R6CH2OH+R11C2H5=C2H4Z+CH3OH 2.40E+12 0 0

382 HCHO+R1H=R5CHO+H2 1.30E+08 1.6 2100 418 R6CH2OH+R11C2H5=C2H6+HCHO 2.40E+12 0 0

383 HCHO+B4CH=R13CH2CHO 9.60E+13 0 -500 419 R6CH2OH+C2H6=CH3OH+R11C2H5 1.99E+02 3 14000

384 HCHO+B6CH2=R4CH3+R5CHO 1.20E+12 0 0 420 R6CH2OH+B1O=HCHO+R2OH 4.20E+13 0 0

385 HCHO+B1O=R5CHO+R2OH 4.10E+11 0.6 2700 421 R6CH2OH+R2OH=H2O+HCHO 2.40E+13 0 0

386 HCHO+R2OH=R5CHO+H2O 3.40E+09 1.2 -400 422 R6CH2OH+R5CHO=CH3OH+B2CO 1.20E+14 0 0

387 R7CH3O+M=HCHO+R1H+M 1.55E+14 0 13500 423 R6CH2OH+R5CHO=HCHO+HCHO 1.80E+14 0 0

388 R7CH3O+R1H=HCHO+H2 1.80E+13 0 0 424 R6CH2OH+HCHO=CH3OH+R5CHO 5.50E+03 2.8 5900

389 R7CH3O+B6CH2=R4CH3+HCHO 1.80E+13 0 0 425 R6CH2OH+R7CH3O=CH3OH+HCHO 2.40E+13 0 0

390 R7CH3O+B5CH2=R4CH3+HCHO 1.80E+13 0 0 426 R6CH2OH+R6CH2OH=CH3OH+HCHO 1.40E+13 0 0

391 R7CH3O+R4CH3=HCHO+CH4 2.40E+13 0 0 427 CH3OH+R1H=R4CH3+H2O 2.00E+14 0 5300

392 R7CH3O+CH4=R4CH3+CH3OH 1.60E+11 0 8800 428 CH3OH+R1H=R7CH3O+H2 4.20E+06 2.1 4900

296

Rex No Reaction A b Ea

Rex No Reaction A b Ea

429 CH3OH+B6CH2=R6CH2OH+R4CH3 1.50E+12 0 0 465 R14CH3CO+HCHO=CH3CHO+R5CHO 1.80E+11 0 12900

430 CH3OH+B5CH2=R4CH3+R6CH2OH 3.19E+01 3.2 7200 466 R14CH3CO+R7CH3O=CH3OH+CH2COZ 6.00E+12 0 0

431 CH3OH+B5CH2=R4CH3+R7CH3O 1.44E+01 3.1 6900 467 R14CH3CO+R7CH3O=HCHO+CH3CHO 6.00E+12 0 0

432 CH3OH+R9C2HT=C2H2T+R6CH2OH 6.00E+12 0 0 468 R14CH3CO+CH3OH=CH3CHO+R6CH2OH 4.85E+03 3 12300

433 CH3OH+R9C2HT=C2H2T+R7CH3O 1.20E+12 0 0 469 R14CH3CO+R14CH3CO=CH2COZ+CH3CHO 1.20E+13 0 0

434 CH3OH+R10C2H3V=C2H4Z+R6CH2OH 3.19E+01 3.2 7200 470 R13CH2CHO=R14CH3CO 1.00E+13 0 47000

435 CH3OH+R10C2H3V=C2H4Z+R7CH3O 1.44E+01 3.1 6900 471 R13CH2CHO=R1H+CH2COZ 1.60E+13 0 35000

436 CH3OH+B1O=R6CH2OH+R2OH 3.40E+13 0 5500 472 CH3CHO+R1H=H2+R14CH3CO 4.00E+13 0 4200

437 CH3OH+B1O=R7CH3O+R2OH 1.00E+13 0 4700 473 CH3CHO+R4CH3=R14CH3CO+CH4 2.00E-06 5.6 2500

438 CH3OH+R2OH=R6CH2OH+H2O 3.10E+06 2 -340 474 CH3CHO+R10C2H3V=C2H4Z+R14CH3CO 8.10E+10 0 3700

439 CH3OH+R2OH=R7CH3O+H2O 5.40E+05 2 -340 475 CH3CHO+R11C2H5=C2H6+R14CH3CO 1.30E+12 0 8500

440 CH3OH+R7CH3O=CH3OH+R6CH2OH 3.00E+11 0 4100 476 CH3CHO+B1O=R14CH3CO+R2OH 1.40E+13 0 2300

441 R12CHCOV+M=B4CH+B2CO+M 6.00E+15 0 58800 477 CH3CHO+R2OH=R14CH3CO+H2O 4.20E+12 0 500

442 R12CHCOV+R1H=B5CH2+B2CO 1.50E+14 0 0 478 CH3CHO+R7CH3O=R14CH3CO+CH3OH 2.40E+11 0 1800

443 R12CHCOV+R1H=B6CH2+B2CO 1.30E+14 0 0 479 CH3CHO+R13CH2CHO=CH3CHO+R14CH3CO 2.50E+07 0 0

444 R12CHCOV+B5CH2=R9C2HT+HCHO 1.00E+13 0 2000 480 C2H4O#3=CH4+B2CO 1.20E+13 0 57200

445 R12CHCOV+B5CH2=R10C2H3V+B2CO 3.00E+13 0 0 481 C2H4O#3=CH3CHO 7.30E+13 0 57200

446 R12CHCOV+B1O=>B2CO+B2CO+R1H 9.60E+13 0 0 482 C2H4O#3=R4CH3+R5CHO 3.60E+13 0 57200

447 R12CHCOV+R2OH=>R5CHO+B2CO+R1H 1.00E+13 0 0 483 C2H4O#3+R1H=H2+R13CH2CHO 2.00E+13 0 8300

448 CH2COZ+M=B6CH2+B2CO+M 6.57E+15 0 57600 484 C2H4O#3+R1H=H2O+R10C2H3V 5.00E+09 0 5000

449 CH2COZ+M=R12CHCOV+R1H+M 2.70E+17 0 87000 485 C2H4O#3+R1H=C2H4Z+R2OH 9.50E+10 0 5000

450 CH2COZ+R1H=R4CH3+B2CO 1.80E+13 0 3400 486 C2H4O#3+R4CH3=CH4+R13CH2CHO 1.10E+12 0 11800

451 CH2COZ+R1H=R12CHCOV+H2 5.00E+13 0 8000 487 C2H4O#3+R4CH3=R11C2H5+HCHO 1.40E+11 0 7600

452 CH2COZ+B5CH2=C2H4Z+B2CO 1.30E+14 0 0 488 C2H4O#3+R4CH3=C2H4Z+R7CH3O 1.50E+10 0 7600

453 CH2COZ+B1O=B5CH2+CO2 1.80E+12 0 1300 489 C2H4O#3+R9C2HT=C2H2T+R13CH2CHO 1.20E+12 0 9800

454 CH2COZ+B1O=R12CHCOV+R2OH 1.00E+13 0 8000 490 C2H4O#3+R10C2H3V=C2H4Z+R13CH2CHO 2.00E+12 0 9300

455 CH2COZ+R2OH=R12CHCOV+H2O 7.50E+12 0 2000 491 C2H4O#3+R11C2H5=C2H6+R13CH2CHO 6.80E+11 0 11400

456 CH2COZ+R2OH=R4CH3+CO2 2.52E+12 0 0 492 C2H4O#3+B1O=R2OH+R13CH2CHO 1.90E+12 0 5200

457 CH2COZ+R2OH=R6CH2OH+B2CO 4.68E+12 0 0 493 C2H4O#3+R2OH=H2O+R13CH2CHO 1.80E+13 0 3600

458 R14CH3CO+R1H=R4CH3+R5CHO 9.60E+13 0 0 494 C2H4O#3+R5CHO=HCHO+R13CH2CHO 3.70E+12 0 15800

459 R14CH3CO+B6CH2=R4CH3+CH2COZ 1.80E+13 0 0 495 C2H4O#3+R7CH3O=CH3OH+R13CH2CHO 1.30E+12 0 5800

460 R14CH3CO+B5CH2=R4CH3+CH2COZ 1.80E+13 0 0 496 C2H4O#3+R6CH2OH=CH3OH+R13CH2CHO 8.40E+11 0 13400

461 R14CH3CO+B1O=R4CH3+CO2 9.60E+12 0 0 497 C2H4O#3+R14CH3CO=CH3CHO+R13CH2CHO 4.00E+12 0 17500

462 R14CH3CO+R2OH=CH2COZ+H2O 1.20E+13 0 0 498 C2H4O#3+R13CH2CHO=CH3CHO+R13CH2CHO 6.80E+11 0 15400

463 R14CH3CO+R2OH=>R4CH3+B2CO+R2OH 3.00E+13 0 0 499 R15C2H5O=HCHO+R4CH3 8.00E+13 0 21500

464 R14CH3CO+R5CHO=CH3CHO+B2CO 9.00E+12 0 0 500 R15C2H5O=CH3CHO+R1H 2.00E+14 0 23300

297

Rex No Reaction A b Ea

Rex No Reaction A b Ea

501 C2H5OH(+M)=R11C2H5+R2OH(+M) 1.20E+23 -1.5 96000 537 O2+R9C2HT=B2CO+R5CHO 3.80E+13 -0 0

502 C2H5OH(+M)=C2H4Z+H2O(+M) 2.80E+13 0.1 66100 538 O2+R9C2HT=R12CHCOV+B1O 9.00E+12 -0 0

503 C2H5OH(+M)=CH3CHO+H2(+M) 7.20E+11 0.1 91000 539 O2+C2H2T=R9C2HT+R3OOH 1.20E+13 0 74500

504 C2H5OH+R1H=H2+R15C2H5O 1.50E+07 1.6 3040 540 O2+C2H2T=R5CHO+R5CHO 7.00E+07 1.8 30600

505 C2H5OH+B1O=R2OH+R15C2H5O 1.60E+07 2 4450 541 O2+R10C2H3V=C2H2T+R3OOH 1.34E+06 1.6 -400

506 C2H5OH+R2OH=H2O+R15C2H5O 7.50E+11 0.3 1600 542 O2+R10C2H3V=HCHO+R5CHO 4.50E+16 -1 1000

507 C2H5OH+R3OOH=H2O2+R15C2H5O 2.50E+12 0 24000 543 O2+R10C2H3V=B1O+R13CH2CHO 3.30E+11 -0 10

508 C2H5OH+R4CH3=CH4+R15C2H5O 1.40E+02 3 7650 544 O2+C2H4Z=R10C2H3V+R3OOH 4.20E+13 0 57400

509 C2H5OH+R1H=H2+R2OH+C2H4Z 1.20E+07 1.8 5100 545 O2+R11C2H5=R17C2H5OO 2.20E+10 0.8 -600

510 C2H5OH+B1O=R2OH+R2OH+C2H4Z 9.40E+07 1.7 5460 546 O2+R11C2H5=C2H4Z+R3OOH 8.40E+11 0 3900

511 C2H5OH+R2OH=H2O+R2OH+C2H4Z 1.70E+11 0.3 600 547 O2+R11C2H5=R15C2H5O+B1O 1.20E+13 -0 27900

512 C2H5OH+R3OOH=H2O2+R2OH+C2H4Z 1.20E+04 2.5 15700 548 O2+R11C2H5=CH3CHO+R2OH 6.00E+10 0 6900

513 C2H5OH+R4CH3=CH4+R2OH+C2H4Z 2.20E+02 3.2 9600 549 O2+C2H6=R11C2H5+R3OOH 6.00E+13 0 51700

514 C2H5OH+R1H=H2+CH3CHO+R1H 2.60E+07 1.6 2800 550 O2+R2OH=R3OOH+B1O 2.20E+13 0 52500

515 C2H5OH+B1O=R2OH+CH3CHO+R1H 1.90E+07 1.9 1820 551 O2+B2CO=CO2+B1O 2.50E+12 0 47700

516 C2H5OH+R2OH=H2O+CH3CHO+R1H 4.60E+11 0.1 0 552 O2+R5CHO=B2CO+R3OOH 7.60E+12 0 410

517 C2H5OH+R3OOH=H2O2+CH3CHO+R1H 8.20E+03 2.5 10700 553 O2+HCHO=R5CHO+R3OOH 2.00E+13 0 38800

518 C2H5OH+R4CH3=CH4+CH3CHO+R1H 7.30E+02 3 7900 554 O2+R7CH3O=HCHO+R3OOH 2.20E+10 0 1700

519 B1O+B1O+M=O2+M 5.40E+13 0 -1790 555 O2+R6CH2OH=HCHO+R3OOH 1.20E+12 0 0

520 O2+R1H=R2OH+B1O 9.80E+13 0 14800 556 O2+CH3OH=R6CH2OH+R3OOH 2.00E+13 0 44900

521 O2+R1H(+M)=R3OOH(+M) 4.52E+13 0 0 557 O2+R12CHCOV=>B2CO+B2CO+R2OH 1.50E+12 0 2500

522 O2+R1H(+H2O)=R3OOH(+H2O) 4.52E+13 0 0 558 O2+R14CH3CO=R18CH3COOO 2.40E+12 0 0

523 O2+B3C=B2CO+B1O 1.20E+14 0 0 559 O2+R13CH2CHO=>HCHO+R2OH+B2CO 5.90E+09 0 -1400

524 O2+B4CH=R5CHO+B1O 3.30E+13 0 0 560 O2+R13CH2CHO=CH2COZ+R3OOH 1.00E+10 0 -1400

525 O2+B4CH=B2CO+R2OH 3.20E+13 0 0 561 O2+CH3CHO=R14CH3CO+R3OOH 5.00E+13 0 36400

526 O2+B6CH2=>B2CO+R2OH+R1H 3.10E+12 0 0 562 O2+CH3CHO=R13CH2CHO+R3OOH 1.00E+13 0.5 46000

527 O2+B5CH2=R5CHO+R2OH 4.30E+10 0 -500 563 O2+C2H4O#3=R3OOH+R13CH2CHO 5.00E+13 0 48000

528 O2+B5CH2=CO2+H2 6.90E+11 0 500 564 O2+R15C2H5O=CH3CHO+R3OOH 6.00E+10 0 1700

529 O2+B5CH2=>CO2+R1H+R1H 1.60E+12 0 1000 565 R3OOH+R1H=H2+O2 4.30E+13 0 1400

530 O2+B5CH2=B2CO+H2O 1.90E+10 0 -1000 566 R3OOH+R1H=2R2OH 1.70E+14 0 900

531 O2+B5CH2=>B2CO+R2OH+R1H 8.60E+10 0 -500 567 R3OOH+R1H=H2O+B1O 3.00E+13 0 1700

532 O2+B5CH2=HCHO+B1O 1.00E+14 0 4500 568 R3OOH+B6CH2=HCHO+R2OH 3.00E+13 0 0

533 O2+R4CH3(+M)=R8CH3OO(+M) 7.80E+08 1.2 0 569 R3OOH+B5CH2=HCHO+R2OH 1.80E+13 0 0

534 O2+R4CH3=R7CH3O+B1O 1.30E+14 0 31300 570 R3OOH+R4CH3=R7CH3O+R2OH 1.80E+13 0 0

535 O2+R4CH3=HCHO+R2OH 3.00E+30 -4.7 36600 571 R3OOH+CH4=R4CH3+H2O2 9.00E+12 0 24600

536 O2+CH4=R4CH3+R3OOH 4.00E+13 0 56700 572 R3OOH+R9C2HT=R12CHCOV+R2OH 1.80E+13 0 0

298

Rex No Reaction A b Ea

Rex No Reaction A b Ea

573 R3OOH+C2H2T=CH2COZ+R2OH 6.00E+09 0 8000 609 R8CH3OO+C2H2T=CH3OOH+R9C2HT 5.60E+11 0 24500

574 R3OOH+R10C2H3V=>R2OH+R4CH3+B2CO 3.00E+13 0 0 610 R8CH3OO+R10C2H3V=R7CH3O+R13CH2CHO 2.40E+13 0 0

575 R3OOH+C2H4Z=CH3CHO+R2OH 6.00E+09 0 7900 611 R8CH3OO+C2H4Z=R7CH3O+C2H4O#3 1.10E+15 0 20000

576 R3OOH+C2H4Z=C2H4O#3+R2OH 2.20E+12 0 17200 612 R8CH3OO+C2H4Z=CH3OOH+R10C2H3V 3.90E+12 0 24500

577 R3OOH+R11C2H5=>R4CH3+HCHO+R2OH 2.40E+13 0 0 613 R8CH3OO+R11C2H5=R7CH3O+R15C2H5O 2.40E+13 0 0

578 R3OOH+R11C2H5=C2H4Z+H2O2 3.00E+11 0 0 614 R8CH3OO+C2H6=CH3OOH+R11C2H5 2.90E+11 0 14900

579 R3OOH+C2H6=R11C2H5+H2O2 1.30E+13 0 20400 615 R8CH3OO+B1O=R7CH3O+O2 3.60E+13 0 0

580 R3OOH+R2OH=H2O+O2 2.90E+13 0 -500 616 R8CH3OO+R2OH=CH3OH+O2 6.00E+13 0 0

581 R3OOH+B2CO=CO2+R2OH 1.50E+14 0 23600 617 R8CH3OO+R2OH=R7CH3O+R3OOH 3.00E+12 0 0

582 R3OOH+R5CHO=>R2OH+R1H+CO2 3.00E+13 0 0 618 R8CH3OO+B2CO=R7CH3O+CO2 1.00E+14 0 24000

583 R3OOH+HCHO=R5CHO+H2O2 3.00E+12 0 13000 619 R8CH3OO+R5CHO=>R7CH3O+R1H+CO2 3.00E+13 0 0

584 R3OOH+R7CH3O=HCHO+H2O2 3.00E+11 0 0 620 R8CH3OO+HCHO=CH3OOH+R5CHO 1.00E+12 0 12100

585 R3OOH+R6CH2OH=HCHO+H2O2 1.20E+13 0 0 621 R8CH3OO+R7CH3O=HCHO+CH3OOH 3.00E+11 0 0

586 R3OOH+CH3OH=R6CH2OH+H2O2 9.60E+10 0 12600 622 R8CH3OO+R6CH2OH=>R7CH3O+R2OH+HCHO 1.20E+13 0 0

587 R3OOH+R14CH3CO=>R4CH3+CO2+R2OH 3.00E+13 0 0 623 R8CH3OO+CH3OH=CH3OOH+R6CH2OH 1.80E+12 0 13700

588 R3OOH+CH3CHO=R14CH3CO+H2O2 1.00E+12 0 10000 624 R8CH3OO+CH3OH=CH3OOH+R7CH3O 2.80E+11 0 18800

589 R3OOH+C2H4O#3=H2O2+R13CH2CHO 1.60E+12 0 15000 625 R8CH3OO+CH2COZ=CH3OOH+R12CHCOV 1.70E+12 0 27000

590 R3OOH+R3OOH=H2O2+O2 1.30E+11 0 -1630 626 R8CH3OO+R14CH3CO=R4CH3+CO2+R7CH3O 2.40E+13 0 0

591 R3OOH+R3OOH=H2O2+O2 4.20E+14 0 11980 627 R8CH3OO+CH3CHO=CH3OOH+R14CH3CO 1.00E+12 0 12100

592 R2OH+R2OH(+M)=>H2O2(+M) 7.23E+13 -0.4 0 628 R8CH3OO+CH3CHO=CH3OOH+R13CH2CHO 1.70E+12 0 19200

593 H2O2(+M)=>R2OH+R2OH(+M) 3.00E+14 0 48500 629 R8CH3OO+C2H4O#3=CH3OOH+R13CH2CHO 2.20E+12 0 16000

594 H2O2+R1H=H2+R3OOH 1.70E+12 0 3700 630 R8CH3OO+R3OOH=CH3OOH+O2 2.50E+11 0 -1600

595 H2O2+R1H=H2O+R2OH 1.00E+13 0 3600 631 R8CH3OO+R3OOH=>O2+HCHO+H2O 5.00E+10 0 0

596 H2O2+B6CH2=R7CH3O+R2OH 3.00E+13 0 0 632 R8CH3OO+H2O2=CH3OOH+R3OOH 2.40E+12 0 9900

597 H2O2+R10C2H3V=C2H4Z+R3OOH 1.20E+10 0 -600 633 R8CH3OO+R8CH3OO=CH3OH+HCHO+O2 2.50E+10 0 -800

598 H2O2+B1O=R2OH+R3OOH 6.60E+11 0 4000 634 R8CH3OO+R8CH3OO=R7CH3O+R7CH3O+O2 2.50E+10 0 -800

599 H2O2+R2OH=H2O+R3OOH 7.80E+12 0 1300 635 CH3OOH=R7CH3O+R2OH 6.00E+14 0 42300

600 CO2+B5CH2=HCHO+B2CO 2.30E+10 0 0 636 CH3OOH+B1O=R8CH3OO+R2OH 2.00E+13 0 4800

601 R8CH3OO=HCHO+R2OH 1.50E+13 0 47000 637 CH3OOH+R2OH=H2O+R8CH3OO 1.80E+12 0 -370

602 R8CH3OO+R1H=R7CH3O+R2OH 9.60E+13 0 0 638 CH3OOH+R7CH3O=>CH3OH+R2OH+HCHO 1.50E+11 0 6500

603 R8CH3OO+H2=CH3OOH+R1H 3.00E+13 0 26000 639 R17C2H5OO=R16C2H4OOH 4.20E+12 0 36900

604 R8CH3OO+B6CH2=HCHO+R7CH3O 1.80E+13 0 0 640 R17C2H5OO+H2=C2H5OOH+R1H 7.90E+12 0 21000

605 R8CH3OO+B5CH2=HCHO+R7CH3O 1.80E+13 0 0 641 R17C2H5OO+R4CH3=R15C2H5O+R7CH3O 2.00E+12 0 -1200

606 R8CH3OO+R4CH3=R7CH3O+R7CH3O 5.00E+12 0 -1400 642 R17C2H5OO+CH4=C2H5OOH+R4CH3 3.90E+12 0 24000

607 R8CH3OO+CH4=CH3OOH+R4CH3 1.80E+11 0 18500 643 R17C2H5OO+C2H2T=C2H5OOH+R9C2HT 5.60E+11 0 24400

608 R8CH3OO+R9C2HT=R7CH3O+R12CHCOV 2.40E+13 0 0 644 R17C2H5OO+C2H4Z=C2H5OOH+R10C2H3V 3.90E+12 0 24400

299

Rex No Reaction A b Ea

Rex No Reaction A b Ea

645 R17C2H5OO+C2H4Z=R15C2H5O+C2H4O#3 2.30E+16 0 21900 681 R18CH3COOO+R3OOH=CH3COOOH+O2 5.50E+10 0 -2600

646 R17C2H5OO+C2H6=C2H5OOH+R11C2H5 5.10E+12 0 19500 682 R18CH3COOO+C2H5OOH=CH3COOOH+R17C2H5OO 5.00E+11 0 9200

647 R17C2H5OO+H2O=C2H5OOH+R2OH 5.60E+12 0 30600 683 R18CH3COOO+C2H5OOH=>CH3CHO+R2OH+CH3COOOH 5.00E+11 0 9200

648 R17C2H5OO+B2CO=CO2+R15C2H5O 1.00E+14 0 24000 684 R18CH3COOO+R18CH3COOO=>2R4CH3+O2+2CO2 1.70E+12 0 -1000

649 R17C2H5OO+HCHO=C2H5OOH+R5CHO 4.50E+12 0 14400 685 CH3COOOH=>R4CH3+CO2+R2OH 1.00E+16 0 40000

650 R17C2H5OO+CH3OH=C2H5OOH+R7CH3O 2.80E+11 0 18400 686 C2H4Z+R4CH3=>R19C3H7 2.10E+11 0 7350

651 R17C2H5OO+CH3OH=C2H5OOH+R6CH2OH 2.80E+12 0 19500 687 R11C2H5+C2H4Z=>R20C4H9 1.10E+11 0 7300

652 R17C2H5OO+CH2COZ=C2H5OOH+R12CHCOV 1.70E+12 0 24400 688 R11C2H5+R10C2H3V=>C4H8Y 1.50E+13 0 0

653 R17C2H5OO+CH3CHO=C2H5OOH+R14CH3CO 3.90E+12 0 14400 689 R11C2H5+R11C2H5=>C4H10 1.10E+13 0 0

654 R17C2H5OO+CH3CHO=C2H5OOH+R13CH2CHO 1.70E+12 0 19500 690 R5CHO+R10C2H3V=>C2H3CHOZ 1.80E+13 0 0

655 R17C2H5OO+C2H4O#3=C2H5OOH+R13CH2CHO 2.20E+12 0 16300 691 R5CHO+R11C2H5=>C2H5CHO 1.80E+13 0 0

656 R17C2H5OO+R3OOH=O2+C2H5OOH 3.90E+11 0 -1300 692 R6CH2OH+R11C2H5=C3H7OH 1.20E+13 0 0

657 R17C2H5OO+H2O2=C2H5OOH+R3OOH 4.50E+11 0 10800 693 R14CH3CO+R4CH3=>C2H6CO 4.00E+15 -1 0

658 R17C2H5OO+R8CH3OO=>R15C2H5O+R7CH3O+O2 2.00E+11 0 0 694 R14CH3CO+R11C2H5=>C3H8CO 3.10E+14 -1 0

659 R17C2H5OO+CH3OOH=C2H5OOH+R8CH3OO 1.10E+12 0 16300 695 C2H3CHOZ+R2OH=B2CO+R10C2H3V+H2O 1.00E+13 0 0

660 R17C2H5OO+R17C2H5OO=2R15C2H5O+O2 4.10E+10 0 200 696 C2H3CHOZ+B1O=B2CO+R10C2H3V+R2OH 7.20E+12 0 2000

661 R17C2H5OO+R17C2H5OO=C2H5OH+CH3CHO+O2 1.80E+10 0 200 697 C2H3CHOZ+B1O=CH2COZ+R5CHO+R1H 5.00E+07 1.8 80

662 R16C2H4OOH=C2H4O#3+R2OH 1.50E+11 0 20000 698 C2H3CHOZ+R1H=B2CO+R10C2H3V+H2 4.00E+13 0 4200

663 R16C2H4OOH=R6CH2OH+HCHO 2.50E+13 0 27500 699 C2H3CHOZ+R1H=C2H4Z+R5CHO 2.00E+13 0 3500

664 R16C2H4OOH=C2H4Z+R3OOH 2.00E+13 0 23500 700 C2H3CHOZ+O2=B2CO+R10C2H3V+R3OOH 3.00E+13 0 36000

665 C2H5OOH=R15C2H5O+R2OH 4.00E+15 0 42900 701 H2+CN=HCN+H 1.93E+04 2.9 6.8

666 C2H5OOH+R1H=>CH3CHO+R2OH+H2 3.20E+13 0 7700 702 CH4+N=NH+CH3 1.00E+13 0 100.4

667 C2H5OOH+R4CH3=>CH3CHO+R2OH+CH4 5.70E+11 0 8700 703 CH4+CN=HCN+CH3 9.03E+04 2.6 -1.2

668 C2H5OOH+R9C2HT=>CH3CHO+R2OH+C2H2T 6.00E+11 0 9200 704 O2+N=NO+O 9.03E+09 1 27.2

669 C2H5OOH+R10C2H3V=>CH3CHO+R2OH+C2H4Z 1.00E+12 0 8700 705 O2+NH=HNO+O 3.91E+13 0 74.8

670 C2H5OOH+R11C2H5=>CH3CHO+R2OH+C2H6 3.40E+11 0 11400 706 O2+NH=NO+OH 7.59E+10 0 6.4

671 C2H5OOH+R2OH=>CH3CHO+R2OH+H2O 5.90E+12 0 900 707 O2+NH2=HNO+OH 1.51E+12 -0 151

672 C2H5OOH+R5CHO=>CH3CHO+R2OH+HCHO 1.80E+12 0 16700 708 O2+NH2=H2NO+O 1.10E+18 -1 140.6

673 C2H5OOH+R7CH3O=>CH3CHO+R2OH+CH3OH 6.30E+11 0 5500 709 O2+CN=NCO+O 7.23E+12 0 -1.7

674 C2H5OOH+R6CH2OH=>CH3CHO+R2OH+CH3OH 4.20E+11 0 13600 710 O2+NCO=NO+CO2 1.72E+07 0 -3.1

675 C2H5OOH+R14CH3CO=>2CH3CHO+R2OH 2.00E+12 0 18500 711 CO+N2O=CO2+N2 9.77E+10 0 73

676 C2H5OOH+R13CH2CHO=>2CH3CHO+R2OH 3.40E+11 0 15700 712 CO2+N=NO+CO 1.90E+11 0 14.2

677 C2H5OOH+R3OOH=>CH3CHO+R2OH+H2O2 8.00E+11 0 16200 713 N2+CH=HCN+N 1.57E+12 0 75.1

678 C2H5OOH+R8CH3OO=>CH3CHO+R2OH+CH3OOH 1.10E+12 0 16700 714 N2+CH2=HCN+NH 1.00E+13 0 309.6

679 C2H5OOH+R17C2H5OO=>CH3CHO+R2OH+C2H5OOH 1.10E+12 0 16700 715 NO+N2O=N2+NO2 1.00E+14 0 207.8

680 R18CH3COOO+C2H4O#3=CH3COOOH+R13CH2CHO 1.00E+12 0 9300 716 NO+N2H2=N2O+NH2 3.00E+12 0 0

300

Rex No Reaction A b Ea

Rex No Reaction A b Ea

717 NO+C=CN+O 1.93E+13 0 0 753 N2O+O=N2+O2 1.00E+14 0 117.2

718 NO+C=CO+N 2.89E+13 0 0 754 N2O+O=NO+NO 6.92E+13 0 111.4

719 NO+H=>N+OH 2.17E+14 0 207.1 755 N2O+OH=N2+HO2 6.31E+11 0 41.6

720 N+OH=>NO+H 2.83E+13 0 0 756 N2O+N=N2+NO 1.00E+13 0 83.1

721 NO+CH=CO+NH 1.20E+13 0 0 757 N2O+NH=HNO+N2 2.00E+12 0 24.9

722 NO+CH=CN+OH 1.20E+13 0 0 758 N2O+CN=NCO+N2 1.00E+13 0 0

723 NO+CH=HCN+O 9.60E+13 0 0 759 N2O+M=N2+O+M 2.86E+15 0 251

724 NO+CH2=HOCN+H 1.39E+12 0 -4.6 760 NH3+H=NH2+H2 5.42E+05 2.4 41.5

725 NO+CH2(S)=HCN+OH 9.64E+13 0 0 761 NH3+O=>NH2+OH 9.64E+12 0 30.5

726 NO+CH3=HCN+H2O 9.28E+11 0 69.9 762 NH3+OH=NH2+H2O 3.16E+12 0 8.4

727 NO+CH3=H2CN+OH 9.28E+11 0 69.9 763 NH3+HO2=NH2+H2O2 2.51E+12 0 99.8

728 NO+HO2=NO2+OH 2.09E+12 0 -2 764 NH3+NH2=N2H3+H2 7.94E+11 0.5 90.2

729 NO+HO2=HNO+O2 2.00E+11 0 8.3 765 NH3(+M)=NH2+H(+M) 8.30E+15 0 458.7

730 NO+HCCO=HOCN+CO 2.00E+13 0 0 766 NH3+M=NH+H2+M 1.80E+15 0 390.8

731 NO+N=>N2+O 4.28E+13 0 6.6 767 N2H2+H=NNH+H2 1.00E+13 0 4.2

732 N2+O=>NO+N 1.81E+14 0 318.4 768 N2H2+O=NH2+NO 1.00E+13 0 0

733 NO+NH=N2+OH 3.20E+13 0 53.2 769 N2H2+O=NNH+OH 1.00E+11 0.5 0

734 NO+NH=N2O+H 4.16E+14 -0.5 0 770 N2H2+OH=NNH+H2O 1.00E+13 0 8.3

735 NO+NH2=NNH+OH 2.41E+15 -1.2 0 771 N2H2+NH=NNH+NH2 1.00E+13 0 4.2

736 NO+NH2=N2+H2O 5.48E+15 -1.2 0 772 N2H2+NH2=NH+N2H3 1.00E+11 0.5 141.3

737 NO+NNH=N2+HNO 5.00E+13 0 0 773 N2H2+NH2=NH3+NNH 1.00E+13 0 16.6

738 NO+HNO=N2O+OH 2.95E+05 0 0 774 N2H2+M=NNH+H+M 2.50E+16 0 207.8

739 NO+NCO=N2O+CO 1.39E+18 -1.7 3.2 775 N2H2+M=NH+NH+M 7.91E+16 0 415.7

740 NO+M=N+O+M 3.62E+15 0 620.6 776 C2N2+O=NCO+CN 1.29E+14 0 59.3

741 NO2+NO2=NO+NO+O2 2.00E+12 0 112.2 777 C2N2+OH=HOCN+CN 1.87E+11 0 12

742 NO2+H=NO+OH 3.47E+14 0 6.2 778 HCN+O=NCO+H 8.45E+05 2.1 25.6

743 NO2+O=NO+O2 1.00E+13 0 2.5 779 HCN+O=NH+CO 3.19E+05 2.1 25.6

744 NO2+N=NO+NO 8.07E+11 0 0 780 HCN+O=CN+OH 2.22E+05 2.1 25.6

745 NO2+N=N2O+O 1.00E+12 0 0 781 HCN+OH=CN+H2O 9.03E+12 0 44.9

746 NO2+NH=HNO+NO 1.00E+11 0.5 16.6 782 HCN+OH=HOCN+H 5.85E+04 2.4 52.3

747 NO2+NH=N2O+OH 9.71E+12 0 0 783 HCN+OH=HNCO+H 1.98E-03 4 4.2

748 NO2+NH2=N2O+H2O 2.03E+17 -1.7 0 784 HCN+CN=C2N2+H 3.80E+07 1.6 0.4

749 NO2+CN=NCO+NO 3.00E+13 0 0 785 HOCN+H=H2O+CN 1.00E+12 0 0

750 NO2+M=NO+O+M 3.13E+16 0 274.4 786 HOCN+H=H2+NCO 1.00E+12 0 0

751 N2O+C=CN+NO 5.12E+12 0 0 787 HOCN+H=HNCO+H 1.00E+13 0 0

752 N2O+H=N2+OH 4.37E+14 0 79 788 HNCO+H=NCO+H2 2.05E+14 -0 84.7

301

Rex No Reaction A b Ea

Rex No Reaction A b Ea

789 HNCO+H=NH2+CO 1.10E+14 0 53.2 825 O+CN=CO+N 1.02E+13 0 0 790 HNCO+O=NH+CO2 2.00E+13 0 54.5 826 O+NCO=NO+CO 3.16E+13 0 0 791 HNCO+O=HNO+CO 1.90E+12 0 43.1 827 OH+NH=HNO+H 1.00E+12 0.5 8.3 792 HNCO+O=OH+NCO 2.00E+14 0 96.4 828 OH+NH=N+H2O 5.01E+11 0.5 8.3 793 HNCO+OH=NCO+H2O 1.99E+12 0 23.2 829 OH+NH2=>O+NH3 1.99E+10 0.4 2.1 794 HNCO+OH=NH2+CO2 6.62E+11 0 23.2 830 OH+NH2=NH+H2O 5.01E+11 0.5 8.3 795 HNCO+HO2=NCO+H2O2 3.00E+13 0 121.3 831 OH+NNH=N2+H2O 3.16E+13 0 0 796 HNCO+N=NH+NCO 3.98E+13 0 149.7 832 OH+HNO=NO+H2O 1.08E+13 0 0 797 HNCO+NH=NH2+NCO 3.00E+13 0 99.2 833 OH+CN=NCO+H 6.02E+13 0 0 798 HNCO+NH2=NH3+NCO 1.00E+12 0 29.1 834 OH+NCO=NO+HCO 5.00E+12 0 62.8 799 HNCO+M=NH+CO+M 2.40E+16 0 354.5 835 OH+NCO=NO+CO+H 1.00E+13 0 0 800 HNCO+M=H+NCO+M 2.86E+17 0 468.9 836 HO2+NH2=HNO+H2O 1.57E+13 0 0 801 H+NH=N+H2 1.02E+13 0 0 837 HCCO+N=HCN+CO 5.00E+13 0 0 802 H+NH2=NH+H2 6.02E+12 0 0 838 N+N+M=N2+M 6.52E+15 0 0 803 H+NNH=N2+H2 3.98E+13 0 12.5 839 N+NH=N2+H 6.31E+11 0.5 0 804 H+N2H3=NH2+NH2 1.58E+12 0 0 840 N+NH2=N2+H+H 6.93E+13 0 0 805 H+N2H3=NH+NH3 1.00E+11 0 0 841 N+NNH=NH+N2 3.16E+13 0 8.3 806 H+N2H3=N2H2+H2 1.00E+12 0 8.3 842 N+CN=>C+N2 1.81E+14 0 0 807 H+HNO=H2+NO 1.26E+13 0 16.6 843 C+N2=>N+CN 5.24E+13 0 187.9 808 H+NCO=NH+CO 5.24E+13 0 0 844 N+H2CN=N2+CH2 2.00E+13 0 0 809 CH+N=CN+H 1.26E+13 0 0 845 N+NCO=NO+CN 2.77E+18 -1 72.2 810 CH+NH=HCN+H 5.00E+13 0 0 846 N+NCO=N2+CO 1.99E+13 0 0 811 CH+NH2=HCN+H+H 3.00E+13 0 0 847 NH+NH=N2+H+H 5.13E+13 0 0812 CH2+N=HCN+H 5.00E+13 0 0 848 NH+NH2=N2H2+H 1.51E+15 -1 0 813 CH2+NH=HCN+H+H 3.00E+13 0 0 849 NH+NNH=N2+NH2 2.00E+11 0.5 8.3 814 CH3+N=H2CN+H 2.59E+14 0 3.5 850 NH+M=N+H+M 7.57E+14 0 315.9 815 C2H3+N=HCN+CH2 2.00E+13 0 0 851 NH2+NH2=N2H2+H2 3.98E+13 0 49.9 816 H2CCCH+N=HCN+C2H2 1.00E+13 0 0 852 NH2+NH2=NH3+NH 5.00E+13 0 41.8 817 O+NH=N+OH 3.72E+13 0 0 853 NH2+M=NH+H+M 7.91E+23 -2 382.4 818 O+NH=NO+H 5.50E+13 0 0 854 NH2+NNH=N2+NH3 1.00E+13 0 0 819 O+NH2=NH+OH 6.90E+11 0.3 -0.8 855 NH2+HNO=NH3+NO 5.01E+11 0.5 4.2 820 O+NH2=HNO+H 8.93E+14 -0.5 1.4 856 NNH=N2+H 3.00E+08 0 0 821 O+NNH=N2+OH 1.00E+13 0 20.8 857 NNH+M=N2+H+M 2.50E+13 0.5 12.8 822 O+NNH=N2O+H 1.00E+13 0 12.5 858 NNH+O2=N2+HO2 5.00E+12 0 0 823 O+NNH=NH+NO 1.65E+14 -0.2 -4.2 859 N2H3+M=N2H2+H+M 2.50E+16 0 207.8 824 O+HNO=OH+NO 5.01E+11 0.5 8.3 860 N2H3+M=NH2+NH+M 2.50E+16 0 174.6

302

861 HNO+M=H+NO+M 5.09E+16 0 203.7 863 NCO+M=N+CO+M 2.91E+15 0 195.4 862 H2CN+M=HCN+H+M 7.50E+14 0 92 864 H2O+CH=CH2O+H 5.72E+12 0 -3.2

303

Mechanism-IV (Simplified Version of Mechanism-I)

Rex No Reaction A b Ea

Rex No Reaction A b Ea

1 C3H8=>R4CH3+R11C2H5 9.40E+16 0 86903.5 35 R1H+R21C3H7=>C3H8 8.30E+12 0 0

2 C4H10=>R11C2H5+R11C2H5 2.20E+16 0 86135.6 36 R2OH+R21C3H7=>C3H7OH 5.90E+12 0 0

3 C4H10=>R4CH3+R19C3H7 9.70E+16 0 88015.9 37 R3OOH+R21C3H7=>C3H7OOH 4.80E+12 0 0

4 C3H8+O2=>R3OOH+R19C3H7 4.20E+13 0 54334.2 38 R4CH3+R21C3H7=>C4H10 1.50E+13 0 0

5 C4H10+O2=>R3OOH+R20C4H9 4.20E+13 0 54334.3 39 R5CHO+R21C3H7=>C3H7CHO 5.20E+12 0 0

6 R19C3H7=>R4CH3+C2H4Z 2.00E+13 0 31000 40 R6CH2OH+R21C3H7=>C4H9OH 5.10E+12 0 0

7 R19C3H7=>R1H+C3H6Y 3.00E+13 0 38000 41 R7CH3O+R21C3H7=>C4H10O 4.90E+12 0 0

8 R20C4H9=>R11C2H5+C2H4Z 2.00E+13 0 28700 42 R8CH3OO+R21C3H7=>C4H10OO 4.40E+12 0 0

9 R20C4H9=>R1H+C4H8Y 3.00E+13 0 38000 43 R11C2H5+R21C3H7=>C5H12 5.20E+12 0 0

10 R22C4H9=>R4CH3+C3H6Y 2.00E+13 0 31000 44 R21C3H7+R21C3H7=>C6H14 2.30E+12 0 0

11 R19C3H7+O2=>C3H6Y+R3OOH 2.80E+12 0 5000 45 H2+CN=HCN+H 1.93E+04 2.9 6.8

12 R20C4H9+O2=>C4H8Y+R3OOH 1.30E+12 0 5000 46 CH4+N=NH+CH3 1.00E+13 0 100.4

13 B1O+C3H8=>R2OH+R19C3H7 1.00E+14 0 7850 47 CH4+CN=HCN+CH3 9.03E+04 2.6 -1.2

14 B1O+C4H10=>R2OH+R20C4H9 1.00E+14 0 7850 48 O2+N=NO+O 9.03E+09 1 27.2

15 C3H8+R1H=>H2+R21C3H7 9.00E+06 2 5000 49 O2+NH=HNO+O 3.91E+13 0 74.8

16 C4H10+R1H=>H2+R20C4H9 5.70E+07 2 7700 50 O2+NH=NO+OH 7.59E+10 0 6.4

17 C3H8+R2OH=>H2O+R21C3H7 2.60E+06 2 -765 51 O2+NH2=HNO+OH 1.51E+12 -0.4 151

18 C4H10+R2OH=>H2O+R20C4H9 5.40E+06 2 450 52 O2+NH2=H2NO+O 1.10E+18 -1.3 140.6

19 C3H8+R3OOH=>H2O2+R21C3H7 4.00E+11 0 15500 53 O2+CN=NCO+O 7.23E+12 0 -1.7

20 C4H10+R3OOH=>H2O2+R20C4H9 1.20E+12 0 17000 54 O2+NCO=NO+CO2 1.72E+07 0 -3.1

21 C3H8+R4CH3=>CH4+R21C3H7 2.00E+11 0 9600 55 CO+N2O=CO2+N2 9.77E+10 0 73

22 C4H10+R4CH3=>CH4+R20C4H9 6.00E-01 4 8200 56 CO2+N=NO+CO 1.90E+11 0 14.2

23 C3H8+R5CHO=>HCHO+R21C3H7 1.00E+07 1.9 17000 57 N2+CH=HCN+N 1.57E+12 0 75.1

24 C4H10+R5CHO=>HCHO+R20C4H9 2.00E+05 2.5 18500 58 N2+CH2=HCN+NH 1.00E+13 0 309.6

25 C3H8+R6CH2OH=>CH3OH+R21C3H7 6.00E+01 3 12000 59 NO+N2O=N2+NO2 1.00E+14 0 207.8

26 C4H10+R6CH2OH=>CH3OH+R20C4H9 2.00E+02 3 14000 60 NO+N2H2=N2O+NH2 3.00E+12 0 0

27 C3H8+R7CH3O=>CH3OH+R21C3H7 1.50E+11 0 4500 61 NO+C=CN+O 1.93E+13 0 0

28 C4H10+R7CH3O=>CH3OH+R20C4H9 3.20E+11 0 7300 62 NO+C=CO+N 2.89E+13 0 0

29 C3H8+R8CH3OO=>CH3OOH+R21C3H7 3.00E+12 0 17500 63 NO+H=>N+OH 2.17E+14 0 207.1

30 C4H10+R8CH3OO=>CH3OOH+R20C4H9 1.20E+13 0 20000 64 N+OH=>NO+H 2.83E+13 0 0

31 C3H8+R11C2H5=>C2H6+R21C3H7 2.00E+11 0 11000 65 NO+CH=CO+NH 1.20E+13 0 0

32 C4H10+R11C2H5=>C2H6+R20C4H9 6.00E+11 0 13500 66 NO+CH=CN+OH 1.20E+13 0 0

33 C3H8+R21C3H7=>C3H8+R19C3H7 8.40E-03 4.2 8700 67 NO+CH=HCN+O 9.60E+13 0 0

34 C4H10+R21C3H7=>C3H8+R22C4H9 5.60E-03 4.2 8000 68 NO+CH2=HOCN+H 1.39E+12 0 -4.6

304

Rex No Reaction A b Ea

Rex No Reaction A b Ea

69 NO+CH2(S)=HCN+OH 9.64E+13 0 0 103 N2O+M=N2+O+M 2.86E+15 0 251

70 NO+CH3=HCN+H2O 9.28E+11 0 69.9 104 NH3+H=NH2+H2 5.42E+05 2.4 41.5

71 NO+CH3=H2CN+OH 9.28E+11 0 69.9 105 NH3+O=>NH2+OH 9.64E+12 0 30.5

72 NO+HO2=NO2+OH 2.09E+12 0 -2 106 NH3+OH=NH2+H2O 3.16E+12 0 8.4

73 NO+HO2=HNO+O2 2.00E+11 0 8.3 107 NH3+HO2=NH2+H2O2 2.51E+12 0 99.8

74 NO+HCCO=HOCN+CO 2.00E+13 0 0 108 NH3+NH2=N2H3+H2 7.94E+11 0.5 90.2

75 NO+N=>N2+O 4.28E+13 0 6.6 109 NH3(+M)=NH2+H(+M) 8.30E+15 0 458.7

76 N2+O=>NO+N 1.81E+14 0 318.4 110 NH3+M=NH+H2+M 1.80E+15 0 390.8

77 NO+NH=N2+OH 3.20E+13 0 53.2 111 N2H2+H=NNH+H2 1.00E+13 0 4.2

78 NO+NH=N2O+H 4.16E+14 -0.5 0 112 N2H2+O=NH2+NO 1.00E+13 0 0

79 NO+NH2=NNH+OH 2.41E+15 -1.2 0 113 N2H2+O=NNH+OH 1.00E+11 0.5 0

80 NO+NH2=N2+H2O 5.48E+15 -1.2 0 114 N2H2+OH=NNH+H2O 1.00E+13 0 8.3

81 NO+NNH=N2+HNO 5.00E+13 0 0 115 N2H2+NH=NNH+NH2 1.00E+13 0 4.2

82 NO+HNO=N2O+OH 2.95E+05 0 0 116 N2H2+NH2=NH+N2H3 1.00E+11 0.5 141.3

83 NO+NCO=N2O+CO 1.39E+18 -1.7 3.2 117 N2H2+NH2=NH3+NNH 1.00E+13 0 16.6

84 NO+M=N+O+M 3.62E+15 0 620.6 118 N2H2+M=NNH+H+M 2.50E+16 0 207.8

85 NO2+NO2=NO+NO+O2 2.00E+12 0 112.2 119 N2H2+M=NH+NH+M 7.91E+16 0 415.7

86 NO2+H=NO+OH 3.47E+14 0 6.2 120 C2N2+O=NCO+CN 1.29E+14 0 59.3

87 NO2+O=NO+O2 1.00E+13 0 2.5 121 C2N2+OH=HOCN+CN 1.87E+11 0 12

88 NO2+N=NO+NO 8.07E+11 0 0 122 HCN+O=NCO+H 8.45E+05 2.1 25.6

89 NO2+N=N2O+O 1.00E+12 0 0 123 HCN+O=NH+CO 3.19E+05 2.1 25.6

90 NO2+NH=HNO+NO 1.00E+11 0.5 16.6 124 HCN+O=CN+OH 2.22E+05 2.1 25.6

91 NO2+NH=N2O+OH 9.71E+12 0 0 125 HCN+OH=CN+H2O 9.03E+12 0 44.9

92 NO2+NH2=N2O+H2O 2.03E+17 -1.7 0 126 HCN+OH=HOCN+H 5.85E+04 2.4 52.3

93 NO2+CN=NCO+NO 3.00E+13 0 0 127 HCN+OH=HNCO+H 1.98E-03 4 4.2

94 NO2+M=NO+O+M 3.13E+16 0 274.4 128 HCN+CN=C2N2+H 3.80E+07 1.6 0.4

95 N2O+C=CN+NO 5.12E+12 0 0 129 HOCN+H=H2O+CN 1.00E+12 0 0

96 N2O+H=N2+OH 4.37E+14 0 79 130 HOCN+H=H2+NCO 1.00E+12 0 0

97 N2O+O=N2+O2 1.00E+14 0 117.2 131 HOCN+H=HNCO+H 1.00E+13 0 0

98 N2O+O=NO+NO 6.92E+13 0 111.4 132 HNCO+H=NCO+H2 2.05E+14 -0.3 84.7

99 N2O+OH=N2+HO2 6.31E+11 0 41.6 133 HNCO+H=NH2+CO 1.10E+14 0 53.2

100 N2O+N=N2+NO 1.00E+13 0 83.1 134 HNCO+O=NH+CO2 2.00E+13 0 54.5

101 N2O+NH=HNO+N2 2.00E+12 0 24.9 135 HNCO+O=HNO+CO 1.90E+12 0 43.1

102 N2O+CN=NCO+N2 1.00E+13 0 0 136 HNCO+O=OH+NCO 2.00E+14 0 96.4

305

Rex No Reaction A b Ea

Rex No Reaction A b Ea

137 HNCO+OH=NCO+H2O 1.99E+12 0 23.2 173 OH+NH2=>O+NH3 1.99E+10 0.4 2.1

138 HNCO+OH=NH2+CO2 6.62E+11 0 23.2 174 OH+NH2=NH+H2O 5.01E+11 0.5 8.3

139 HNCO+HO2=NCO+H2O2 3.00E+13 0 121.3 175 OH+NNH=N2+H2O 3.16E+13 0 0

140 HNCO+N=NH+NCO 3.98E+13 0 149.7 176 OH+HNO=NO+H2O 1.08E+13 0 0

141 HNCO+NH=NH2+NCO 3.00E+13 0 99.2 177 OH+CN=NCO+H 6.02E+13 0 0

142 HNCO+NH2=NH3+NCO 1.00E+12 0 29.1 178 OH+NCO=NO+HCO 5.00E+12 0 62.8

143 HNCO+M=NH+CO+M 2.40E+16 0 354.5 179 OH+NCO=NO+CO+H 1.00E+13 0 0

144 HNCO+M=H+NCO+M 2.86E+17 0 468.9 180 HO2+NH2=HNO+H2O 1.57E+13 0 0

145 H+NH=N+H2 1.02E+13 0 0 181 HCCO+N=HCN+CO 5.00E+13 0 0

146 H+NH2=NH+H2 6.02E+12 0 0 182 N+N+M=N2+M 6.52E+15 0 0

147 H+NNH=N2+H2 3.98E+13 0 12.5 183 N+NH=N2+H 6.31E+11 0.5 0

148 H+N2H3=NH2+NH2 1.58E+12 0 0 184 N+NH2=N2+H+H 6.93E+13 0 0

149 H+N2H3=NH+NH3 1.00E+11 0 0 185 N+NNH=NH+N2 3.16E+13 0 8.3

150 H+N2H3=N2H2+H2 1.00E+12 0 8.3 186 N+CN=>C+N2 1.81E+14 0 0

151 H+HNO=H2+NO 1.26E+13 0 16.6 187 C+N2=>N+CN 5.24E+13 0 187.9

152 H+NCO=NH+CO 5.24E+13 0 0 188 N+H2CN=N2+CH2 2.00E+13 0 0

153 CH+N=CN+H 1.26E+13 0 0 189 N+NCO=NO+CN 2.77E+18 -1 72.2

154 CH+NH=HCN+H 5.00E+13 0 0 190 N+NCO=N2+CO 1.99E+13 0 0

155 CH+NH2=HCN+H+H 3.00E+13 0 0 191 NH+NH=N2+H+H 5.13E+13 0 0

156 CH2+N=HCN+H 5.00E+13 0 0 192 NH+NH2=N2H2+H 1.51E+15 -0.5 0

157 CH2+NH=HCN+H+H 3.00E+13 0 0 193 NH+NNH=N2+NH2 2.00E+11 0.5 8.3

158 CH3+N=H2CN+H 2.59E+14 0 3.5 194 NH+M=N+H+M 7.57E+14 0 315.9

159 C2H3+N=HCN+CH2 2.00E+13 0 0 195 NH2+NH2=N2H2+H2 3.98E+13 0 49.9

160 H2CCCH+N=HCN+C2H2 1.00E+13 0 0 196 NH2+NH2=NH3+NH 5.00E+13 0 41.8

161 O+NH=N+OH 3.72E+13 0 0 197 NH2+M=NH+H+M 7.91E+23 -2 382.4

162 O+NH=NO+H 5.50E+13 0 0 198 NH2+NNH=N2+NH3 1.00E+13 0 0

163 O+NH2=NH+OH 6.90E+11 0.3 -0.8 199 NH2+HNO=NH3+NO 5.01E+11 0.5 4.2

164 O+NH2=HNO+H 8.93E+14 -0.5 1.4 200 NNH=N2+H 3.00E+08 0 0

165 O+NNH=N2+OH 1.00E+13 0 20.8 201 NNH+M=N2+H+M 2.50E+13 0.5 12.8

166 O+NNH=N2O+H 1.00E+13 0 12.5 202 NNH+O2=N2+HO2 5.00E+12 0 0

167 O+NNH=NH+NO 1.65E+14 -0.2 -4.2 203 N2H3+M=N2H2+H+M 2.50E+16 0 207.8

168 O+HNO=OH+NO 5.01E+11 0.5 8.3 204 N2H3+M=NH2+NH+M 2.50E+16 0 174.6

169 O+CN=CO+N 1.02E+13 0 0 205 HNO+M=H+NO+M 5.09E+16 0 203.7

170 O+NCO=NO+CO 3.16E+13 0 0 206 H2CN+M=HCN+H+M 7.50E+14 0 92

171 OH+NH=HNO+H 1.00E+12 0.5 8.3 207 NCO+M=N+CO+M 2.91E+15 0 195.4

172 OH+NH=N+H2O 5.01E+11 0.5 8.3 208 H2O+CH=CH2O+H 5.72E+12 0 -3.2

306

Annexure-II

(Species Thermo-chemical data)

307

Species Theromochemical Data

THERMO ALL 300.000 1000.000 5000.000 N2 Ranzi 0N 2C 0H 0O 0G 0300.00 5000.00 1000.00 1 2.9266400E+00 1.4879770E-03 -5.6847603E-07 1.0097040E-10 -6.7533509E-15 2 -922.76760E+00 5.9805290E+00 3.2986770E+00 1.4082399E-03 -3.9632218E-06 3 5.6415148E-09 -2.4448540E-12 -1020.9000E00 3.9503720E+00 4 HE Ranzi 0HE 2C 0H 0O 0G 0300.00 5000.00 1000.00 1 3.1250000E+00 -1.4062505E-03 9.3750049E-07 -1.5625008E-10 0.0000000E+00 2 -940.68700E+00 -2.4124130E+00 2.5000000E+00 0.0000000E+00 0.0000000E+00 3 0.0000000E+00 0.0000000E+00 -745.37510E+00 0.9153489E+00 4 AR 120186AR 1 G 0300.00 5000.00 1000.00 1 0.02500000E+02 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 2 -0.07453750E+04 0.04366001E+02 0.02500000E+02 0.00000000E+00 0.00000000E+00 3 0.00000000E+00 0.00000000E+00-0.07453750E+04 0.04366001E+02 4 B1O O 1 G 0300.00 5000.00 1000.00 1 0.02542060E+02-0.02755062E-03-0.03102803E-07 0.04551067E-10-0.04368052E-14 2 0.02923080E+06 0.04920308E+02 0.02946429E+02-0.01638166E-01 0.02421032E-04 3 -0.01602843E-07 0.03890696E-11 0.02914764E+06 0.02963995E+02 4 B2CO C 1O 1 G 0300.00 5000.00 1000.00 1 0.03025078E+02 0.01442689E-01-0.05630828E-05 0.01018581E-08-0.06910952E-13 2 -0.01426835E+06 0.06108218E+02 0.03262452E+02 0.01511941E-01-0.03881755E-04 3 0.05581944E-07-0.02474951E-10-0.01431054E+06 0.04848897E+02 4 B3C C 1 G 0300.00 5000.00 1000.00 1 0.02602087E+02-0.01787081E-02 0.09087041E-06-0.01149933E-09 0.03310844E-14 2 0.08542154E+06 0.04195177E+02 0.02498585E+02 0.08085777E-03-0.02697697E-05 3 0.03040729E-08-0.01106652E-11 0.08545878E+06 0.04753459E+02 4 B4CH C 1H 1 G 0300.00 5000.00 1000.00 1 0.02196223E+02 0.02340381E-01-0.07058201E-05 0.09007582E-09-0.03855040E-13 2 0.07086723E+06 0.09178373E+02 0.03200202E+02 0.02072876E-01-0.05134431E-04 3 0.05733890E-07-0.01955533E-10 0.07045259E+06 0.03331588E+02 4 B5CH2 CH2t C 1H 2 G 0300.00 5000.00 1000.00 1 0.03636408E+02 0.01933057E-01-0.01687016E-05-0.01009899E-08 0.01808256E-12 2 0.04534134E+06 0.02156561E+02 0.03762237E+02 0.01159819E-01 0.02489585E-05 3 0.08800836E-08-0.07332435E-11 0.04536791E+06 0.01712578E+02 4 B6CH2 CH2s C 1H 2 G 0300.00 5000.00 1000.00 1 0.03552889E+02 0.02066788E-01-0.01914116E-05-0.01104673E-08 0.02021350E-12 2 0.04984975E+06 0.01686570E+02 0.03971265E+02-0.01699089E-02 0.01025369E-04 3 0.02492551E-07-0.01981266E-10 0.04989368E+06 0.05753207E+00 4 H2 C 0H 2O 0 G 0300.00 5000.00 1000.00 1 2.50170E+00 1.78083E-03 -7.80013E-07 1.48437E-10 -1.03401E-14 2 -6.86891E+02 1.25553E+00 3.43853E+00 1.44314E-04 -1.08191E-07 3 2.16839E-10 -5.54307E-14 -1.03749E+03 -3.92682E+00 4 H2O C 0H 2O 1 G 0300.00 5000.00 1000.00 1 2.68039E+00 3.09623E-03 -9.31393E-07 1.34865E-10 -7.70007E-15 2 -2.99236E+04 6.77857E+00 3.97559E+00 -4.41834E-04 2.45596E-06 3 -1.24431E-09 2.26702E-13 -3.02810E+04 7.71523E-02 4 O2 C 0H 0O 2 G 0300.00 5000.00 1000.00 1 3.19345E+00 1.56657E-03 -6.90657E-07 1.32082E-10 -9.23577E-15 2 -1.05228E+03 5.96618E+00 3.08809E+00 1.60342E-03 -5.34550E-07 3 2.80793E-11 2.98899E-15 -9.93828E+02 6.61069E+00 4 H2O2 C 0H 2O 2 G 0300.00 5000.00 1000.00 1 5.20269E+00 3.07820E-03 -8.47786E-07 1.14867E-10 -6.24436E-15 2 -1.81737E+04 -2.81106E+00 2.79724E+00 9.30806E-03 -3.27081E-06 3 -3.91853E-09 2.63341E-12 -1.75951E+04 9.47142E+00 4 CH4 C 1H 4O 0 G 0300.00 5000.00 1000.00 1 1.61991E+00 1.03080E-02 -3.71228E-06 6.14185E-10 -3.86748E-14 2 -1.00748E+04 9.98982E+00 2.31954E+00 6.54738E-03 -7.48051E-07 3 2.60912E-09 -1.95537E-12 -9.99764E+03 7.24965E+00 4 HCHO C 1H 2O 1 G 0300.00 5000.00 1000.00 1 2.91430E+00 6.64407E-03 -2.45282E-06 4.12836E-10 -2.63040E-14 2 -1.52827E+04 7.43680E+00 2.41049E+00 7.02041E-03 -4.22947E-06 3 4.40116E-09 -2.12647E-12 -1.49519E+04 1.06246E+01 4 CH3OH C 1H 4O 1 G 0300.00 5000.00 1000.00 1 3.27626E+00 1.05432E-02 -3.54918E-06 5.58743E-10 -3.39236E-14 2 -2.58917E+04 6.60656E+00 1.85957E+00 1.25312E-02 -4.47107E-06 3 1.73293E-09 -8.71066E-13 -2.52879E+04 1.46835E+01 4 CO2 C 1H 0O 2 G 0300.00 5000.00 1000.00 1 2.73827E+00 6.09914E-03 -2.81755E-06 5.57282E-10 -3.99470E-14 2 -4.82637E+04 8.67355E+00 2.67844E+00 6.31159E-03 1.20975E-06 3 -7.46647E-09 3.79399E-12 -4.84134E+04 8.57691E+00 4 CH3OOH C 1H 4O 2 G 0300.00 5000.00 1000.00 1

308

6.37596E+00 1.07372E-02 -3.68666E-06 5.88827E-10 -3.61266E-14 2 -1.84341E+04 -6.12840E+00 3.09218E+00 1.80223E-02 -7.11862E-06 3 -1.47978E-09 1.45517E-12 -1.74300E+04 1.13028E+01 4 C2H2T C 2H 2O 0 G 0300.00 5000.00 1000.00 1 3.00338E+00 7.58476E-03 -3.11008E-06 5.64312E-10 -3.79570E-14 2 2.62468E+04 5.29247E+00 2.54593E+00 1.14007E-02 -7.07123E-06 3 -6.00363E-10 1.71894E-12 2.60564E+04 6.56609E+00 4 C2H4Z C 2H 4O 0 G 0300.00 5000.00 1000.00 1 3.99720E-01 1.67299E-02 -6.80909E-06 1.22922E-09 -8.23928E-14 2 5.63749E+03 1.97729E+01 1.31810E+00 1.44460E-02 -2.74335E-06 3 -3.10835E-09 1.52772E-12 5.26817E+03 1.47233E+01 4 C2H6 C 2H 6O 0 G 0300.00 5000.00 1000.00 1 3.94109E-01 2.11928E-02 -8.08560E-06 1.39339E-09 -9.03005E-14 2 -1.10714E+04 1.96366E+01 9.75454E-01 1.88110E-02 -1.46453E-06 3 -6.38247E-09 2.84067E-12 -1.13111E+04 1.65514E+01 4 CH2COZ C 2H 2O 1 G 0300.00 5000.00 1000.00 1 5.35267E+00 6.94209E-03 -2.50061E-06 4.13231E-10 -2.59692E-14 2 -7.81007E+03 -3.80283E+00 2.99539E+00 1.23540E-02 -4.06499E-06 3 -3.34608E-09 2.24152E-12 -7.15097E+03 8.53716E+00 4 CH3CHO 0C 2H 4O 1 G 0300.00 5000.00 1000.00 1 0.05869E+02 0.10794E-01 -0.03646E-04 0.05413E-08 -0.02897E-12 2 -0.02265E+06 -0.06013E+02 -5.97842E+01 4.89059E-01 -1.27143E-03 3 1.42135E-06 -5.67547E-10 -1.52478E+04 2.71669E+02 4 !coefficients de CHEMKIN a haute temperature et THERGAS a basse temperature! C2H5OH C 2H 6O 1 G 0300.00 5000.00 1000.00 1 5.62516E+00 1.59916E-02 -5.36799E-06 8.43422E-10 -5.11406E-14 2 -3.10498E+04 -3.61961E+00 9.39858E-01 2.61811E-02 -9.25134E-06 3 -3.45825E-09 2.62098E-12 -2.96238E+04 2.12634E+01 4 C2H5OOH C 2H 6O 2 G 0300.00 5000.00 1000.00 1 8.86549E+00 1.46991E-02 -4.66630E-06 7.03129E-10 -4.13262E-14 2 -2.34663E+04 -1.74646E+01 2.03266E+00 3.20310E-02 -1.79773E-05 3 2.38766E-09 1.07206E-12 -2.15063E+04 1.82187E+01 4 CH3COOOH C 2H 4O 3 G 0300.00 5000.00 1000.00 1 7.87651E+00 1.42400E-02 -4.81648E-06 7.62396E-10 -4.65514E-14 2 -4.39851E+04 -9.71105E+00 2.19569E-01 3.53131E-02 -2.24276E-05 3 3.22888E-09 1.67243E-12 -4.19548E+04 2.96617E+01 4 ! Ajout produits en C2+ !C3H4 0C 3H 4 G 0300.00 5000.00 1000.00 1 ! .54693928E+01 .12151568E-01 -.43443515E-05 .71433565E-09 -.44747395E-13 2 ! .19852377E+05 -.54474335E+01 .22271647E+01 .19307628E-01 -.70081351E-05 3 !-.27282026E-08 .21393857E-11 .20828311E+05 .11726395E+02 4 C3H6Y 0C 3H 6 G 0300.00 5000.00 1000.00 1 .50026493E+01 .17638993E-01 -.62266308E-05 .10151433E-08 -.63235977E-13 2 -.27056152E+03 -.24723434E+01 .55598283E+00 .27091531E-01 -.10752104E-04 3 -.97539210E-09 .14314721E-11 .11570190E+04 .21344173E+02 4 C3H8 0C 3H 8 G 0300.00 5000.00 1000.00 1 .54638848E+01 .22160569E-01 -.77296281E-05 .12495476E-08 -.77377605E-13 2 -.15629374E+05 -.62309151E+01 -.31831896E+00 .34746405E-01 -.12885018E-04 3 -.35057037E-08 .30165358E-11 -.13851594E+05 .24514595E+02 4 !C4H2 0C 4H 2 G 0300.00 5000.00 1000.00 1 ! .82167263E+01 .75165699E-02 -.28333620E-05 .48376197E-09 -.31125981E-13 2 ! .53914359E+05 -.19323837E+02 .45411844E+01 .16946664E-01 -.58588685E-05 3 !-.70578716E-08 .47811238E-11 .54806316E+05-.54062080E+00 4 !C4H4 0C 4H 4 G 0300.00 5000.00 1000.00 1 ! .74600129E+01 .13268776E-01 -.48047741E-05 .79804358E-09 -.50392033E-13 2 ! .33450691E+05 -.13594856E+02 .18884374E+01 .27130427E-01 -.11816426E-04 3 !-.46318047E-08 .40962659E-11 .34956789E+05 .15309685E+02 4 C4H6Z2 0C 4H 6 G 0300.00 5000.00 1000.00 1 .80518456E+01 .17540889E-01 -.61760657E-05 .10047656E-08 -.62479542E-13 2 .95697949E+04 -.18611710E+02 -.29224473E+00 .38725201E-01 -.16706719E-04 3 -.81080902E-08 .67421541E-11 .11749236E+05 .24444702E+02 4 C4H8Y 0C 4H 8 G 0300.00 5000.00 1000.00 1 0.93001947E+01 0.19871462E-01-0.65713975E-05 0.10258888E-08-0.62160394E-13 2 -0.46649707E+04-0.24260300E+02-0.25869742E+00 0.41475497E-01-0.21317686E-04 3 0.27918821E-08 0.85749311E-12-0.16180958E+04 0.26720718E+02 4 C4H10 0C 4H 10 G 0300.00 5000.00 1000.00 1 .77133317E+01 .27767614E-01 -.96156327E-05 .15456056E-08 -.95281279E-13 2 -.19425240E+05 -.16262451E+02 .59979584E-01 .44005580E-01 -.15532127E-04 3 -.52806315E-08 .40442116E-11 -.17040045E+05 .24565849E+02 4 C2H3CHOZ 0C 3H 4O 1 G 0300.00 5000.00 1000.00 1 .12311886E+02 .12961588E-01 -.61774654E-05 .12501405E-08 -.91169971E-13 2 -.15218951E+05 -.42303177E+02 .93137437E+00 .35574418E-01 -.33347264E-04 3 .28398034E-07 -.11395644E-10 -.10614329E+05 .21059492E+02 4 C2H5CHO 0C 3H 6O 1 G 0300.00 5000.00 1000.00 1 .70107722E+01 .18013448E-01 -.62295217E-05 .10005839E-08 -.61661722E-13 2 -.25691457E+05 -.95488281E+01 .28277023E+01 .25430365E-01 -.61913220E-05 3

309

-.50245177E-08 .26785609E-11 -.24271348E+05 .13234089E+02 4 !CH3OCH3 0C 2H 6O 1 G 0300.00 5000.00 1000.00 1 ! .48582563E+01 .17240373E-01 -.59518788E-05 .95503494E-09 -.58825550E-13 2 ! -.24755031E+05 -.13852615E+01 .20368140E+01 .21299208E-01 -.51627690E-05 3 ! -.20305686E-08 .88250571E-12 -.23667908E+05 .14411049E+02 4 !CH3OOCH3 0C 2H 6O 2 G 0300.00 5000.00 1000.00 1 ! .83690472E+01 .14833436E-01 -.46565133E-05 .69703088E-09 -.40832690E-13 2 ! -.18533230E+05 -.15578167E+02 .30638237E+01 .28614834E-01 -.24377980E-04 3 ! .19129631E-07 -.72663607E-11 -.16707926E+05 .12810528E+02 4 C3H7OH 0C 3H 8O 1 G 0300.00 5000.00 1000.00 1 .71674681E+01 .22466624E-01 -.76292372E-05 .12097231E-08 -.73884075E-13 2 -.34686773E+05 -.95393562E+01 .12350693E+01 .34453284E-01 -.10589133E-04 3 -.54856804E-08 .35146994E-11 -.32804938E+05 .22268148E+02 4 C2H6CO 0C 3H 6O 1 G 0300.00 5000.00 1000.00 1 .59975996E+01 .19679097E-01 -.70154574E-05 .11513579E-08 -.72035416E-13 2 -.29362656E+05 -.55254784E+01 .14577827E+01 .28063715E-01 -.90218518E-05 3 -.24536706E-08 .16730232E-11 -.27794104E+05 .19218454E+02 4 C3H8CO 0C 4H 8O 1 G 0300.00 5000.00 1000.00 1 .87888947E+01 .24174010E-01 -.83446403E-05 .13376648E-08 -.82271822E-13 2 -.33018367E+05 -.17819489E+02 .27316518E+01 .35815358E-01 -.11085016E-04 3 -.44516226E-08 .28435873E-11 -.31006189E+05 .14949604E+02 4 !CH3COCHO 0C 3H 4O 2 G 0300.00 5000.00 1000.00 1 ! .89256687E+01 .13401341E-01 -.45334914E-05 .71644690E-09 -.43629983E-13 2 ! -.36391773E+05 -.23305817E+02 .36583393E+01 .17818777E-01 .12335082E-04 3 ! -.25004601E-07 .96781515E-11 -.34470117E+05 .63711262E+01 4 !CH3COCH2OH 0C 3H 6O 2 G 0300.00 5000.00 1000.00 1 ! .18422323E+02 .15847507E-02 .22200786E-05 -.75747592E-09 .68857395E-13 2 ! -.52232094E+05 -.69094208E+02 .29494412E+01 .29086677E-01 -.10206494E-04 3 ! -.26419480E-09 .92838457E-13 -.46496102E+05 .16329613E+02 4 !CH3COCOCH3 0C 4H 6O 2 G 0300.00 5000.00 1000.00 1 ! .10088178E+02 .20814884E-01 -.72801195E-05 .11796960E-08 -.73203515E-13 2 ! -.44156449E+05 -.21426254E+02 .20524170E+01 .39215170E-01 -.16422011E-04 3 ! -.39475361E-08 .38206075E-11 -.41770484E+05 .20989098E+02 4 R1H C 0H 1O 0 G 0300.00 5000.00 1000.00 1 2.51382E+00 4.09189E-06 -2.41082E-09 5.71874E-13 -4.70917E-17 2 2.54654E+04 -5.34746E-01 2.51984E+00 -2.59920E-05 6.27898E-08 3 -6.29951E-11 2.23973E-14 2.54641E+04 -5.63259E-01 4 R2OH C 0H 1O 1 G 0300.00 5000.00 1000.00 1 3.04144E+00 6.51385E-04 -1.91218E-08 -1.04196E-13 4.00330E-17 2 3.90412E+03 4.81762E+00 3.67780E+00 -2.14153E-04 5.70231E-08 3 1.71404E-10 -1.84629E-14 3.63597E+03 1.19670E+00 4 R3OOH C 0H 1O 2 G 0300.00 5000.00 1000.00 1 4.72022E+00 1.38622E-03 -1.68457E-07 1.05843E-11 -2.40717E-16 2 -2.41430E+02 -6.85165E-01 1.84854E+00 1.07988E-02 -8.54635E-06 3 4.18415E-10 1.44074E-12 3.26446E+02 1.34319E+01 4 !R3OOH C 0H 1O 2 G 0300.00 5000.00 1000.00 1 ! 0.52347851E+01 0.77814487E-03-0.70662331E-07 0.54676693E-11-0.28544852E-15 2 !-0.29590332E+02-0.36773567E+01 0.14897960E+01 0.13534530E-01-0.15868774E-04 3 ! 0.86208445E-08-0.18269988E-11 0.81474207E+03 0.14919666E+02 4 R4CH3 C 1H 3O 0 G 0300.00 5000.00 1000.00 1 1.02702E+00 9.49641E-03 -3.82860E-06 6.86498E-10 -4.57900E-14 2 1.67624E+04 1.53006E+01 2.94974E+00 5.11940E-03 -8.75334E-07 3 6.64224E-10 -5.42393E-13 1.61486E+04 5.05087E+00 4 R5CHO C 1H 1O 1 G 0300.00 5000.00 1000.00 1 0.36094091E+01 0.28745262E-02-0.98788814E-06 0.15840323E-09-0.97735176E-14 2 0.32321035E+04 0.54304714E+01 0.35340273E+01 0.20234731E-02 0.51834081E-06 3 -0.37246076E-09-0.60802857E-13 0.33738574E+04 0.62388401E+01 4 R6CH2OH C 1H 3O 1 G 0300.00 5000.00 1000.00 1 0.59332314E+01 0.36190501E-02-0.61752752E-06 0.59083634E-10-0.25698620E-14 2 -0.36182065E+04-0.61733055E+01 0.21966424E+01 0.12963202E-01-0.12844380E-04 3 0.99145598E-08-0.32231225E-11-0.22978342E+04 0.13927387E+02 4 R7CH3O C 1H 3O 1 G 0300.00 5000.00 1000.00 1 6.45804E+00 3.22182E-03 -5.09801E-07 4.41966E-11 -1.69366E-15 2 -8.23233E+02 -1.22475E+01 2.40571E-01 1.87747E-02 -2.13180E-05 3 1.81151E-08 -6.61230E-12 1.35827E+03 2.11815E+01 4 R8CH3OO C 1H 3O 2 G 0300.00 5000.00 1000.00 1 9.76413E+00 3.04276E-03 -4.67054E-07 3.87833E-11 -1.39425E-15 2 -1.91174E+03 -2.69241E+01 1.48937E+00 2.40776E-02 -2.38748E-05 3 1.51535E-08 -4.47557E-12 7.64340E+02 1.69852E+01 4 !R8CH3OO C 1H 3O 2 G 0300.00 5000.00 1000.00 1 ! 0.80223064E+01 0.54452606E-02-0.12291885E-05 0.14579345E-09-0.73380904E-14 2 !-0.64005859E+03-0.16948795E+02 0.17759221E+01 0.21917336E-01-0.18158402E-04 3 ! 0.88169347E-08-0.19743768E-11 0.12389817E+04 0.15793612E+02 4 R9C2HT C 2H 1O 0 G 0300.00 5000.00 1000.00 1 0.40437493E+01 0.36123355E-02-0.95946029E-06 0.12793372E-09-0.69526612E-14 2 0.65947961E+05 0.19703522E+01 0.17718196E+01 0.17070146E-01-0.20073590E-04 3

310

0.88779526E-08-0.83304159E-12 0.65840078E+05 0.11053392E+02 4 R10C2H3V C 2H 3O 0 G 0300.00 5000.00 1000.00 1 0.50588360E+01 0.54012556E-02-0.12119358E-05 0.14271406E-09-0.71272656E-14 2 0.33721695E+05-0.30021477E+01 0.12316554E+01 0.14659354E-01-0.95136020E-05 3 0.36466949E-08-0.62640339E-12 0.34934910E+05 0.17314640E+02 4 R11C2H5 C 2H 5O 0 G 0300.00 5000.00 1000.00 1 3.50261E+00 1.26143E-02 -3.65730E-06 5.16642E-10 -2.90469E-14 2 1.24032E+04 5.44236E+00 5.46580E-01 2.04368E-02 -1.16694E-05 3 4.82541E-09 -1.19281E-12 1.32743E+04 2.09001E+01 4 R12CHCOV C 2H 1O 1 G 0300.00 5000.00 1000.00 1 0.06758073E+02 0.02000400E-01-0.02027607E-05-0.01041132E-08 0.01965165E-12 2 0.01901513E+06-0.09071262E+02 0.05047965E+02 0.04453478E-01 0.02268283E-05 3 -0.01482095E-07 0.02250742E-11 0.01965892E+06 0.04818439E+01 4 R13CH2CHO C 2H 3O 1 G 0300.00 5000.00 1000.00 1 0.05976E+02 0.08131E-01 -0.02744E-04 0.04070E-08 -0.02176E-12 2 0.04903E+04 -0.05045E+02 -5.49040E+01 4.51253E-01 -1.17037E-03 3 1.30375E-06 -5.19201E-10 7.54530E+03 2.51103E+02 4 !coefficients de CHEMKIN a haute temperature et THERGAS a basse temperature! R14CH3CO C 2H 3O 1 G 0300.00 5000.00 1000.00 1 0.10937184E+02 0.54414349E-03-0.15865876E-07-0.23107392E-12 0.46252823E-16 2 -0.60733809E+04-0.33342125E+02 0.38579266E+01 0.54023149E-02 0.94996667E-05 3 -0.93490025E-08 0.20667194E-11-0.26711941E+04 0.85433064E+01 4 R15C2H5O C 2H 5O 1 G 0300.00 5000.00 1000.00 1 8.79327E+00 8.37917E-03 -1.93446E-06 2.29371E-10 -1.13191E-14 2 -6.03107E+03 -2.23324E+01 -6.00093E-01 3.17670E-02 -2.42586E-05 3 1.08137E-08 -2.26856E-12 -3.08491E+03 2.73650E+01 4 R16C2H4OOH C 2H 5O 2 G 0300.00 5000.00 1000.00 1 0.98452673E+01 0.10040573E-01-0.24779133E-05 0.31358741E-09-0.16472921E-13 2 0.80278027E+03-0.20483879E+02 0.11050612E+01 0.41490670E-01-0.47184953E-04 3 0.30393178E-07-0.80918614E-11 0.28154634E+04 0.22787066E+02 4 R17C2H5OO C 2H 5O 2 G 0300.00 5000.00 1000.00 1 1.13253E+01 8.28625E-03 -1.86203E-06 2.18209E-10 -1.07868E-14 2 -6.98659E+03 -3.29488E+01 6.72056E-01 3.62757E-02 -3.00008E-05 3 1.38479E-08 -2.84583E-12 -3.78886E+03 2.28869E+01 4 !R17C2H5OO C 2H 5O 2 G 0300.00 5000.00 1000.00 1 ! 0.91485682E+01 0.11469599E-01-0.30378105E-05 0.40154724E-09-0.21543680E-13 2 !-0.53995205E+04-0.20566391E+02 0.75042182E+00 0.35625994E-01-0.28113511E-04 3 ! 0.11570777E-07-0.18778768E-11-0.31420464E+04 0.22568413E+02 4 R18CH3COOO C 2H 3O 3 G 0300.00 5000.00 1000.00 1 0.58370619E+01 0.14517937E-01-0.45853781E-05 0.69238965E-09-0.40972888E-13 2 -0.24636797E+05 0.35686111E+00-0.10923432E+01 0.39162144E-01-0.33321889E-04 3 0.13345456E-07-0.16804813E-11-0.23286021E+05 0.34139729E+02 4 R19C3H7 C 3H 7O 0 G 0300.00 5000.00 1000.00 1 4.90850E+00 1.95492E-02 -6.09862E-06 9.08986E-10 -5.30994E-14 2 9.72711E+03 2.41566E-01 -9.97049E-01 4.22637E-02 -3.67683E-05 3 1.83985E-08 -3.66617E-12 1.08489E+04 2.87294E+01 4 R20C4H9 C 4H 9O 0 G 0300.00 5000.00 1000.00 1 7.04485E+00 2.53221E-02 -8.04531E-06 1.21383E-09 -7.14512E-14 2 5.52642E+03 -9.13080E+00 -5.06119E-01 5.07221E-02 -3.74398E-05 3 1.45966E-08 -1.90079E-12 7.19571E+03 2.83231E+01 4 C4H8Y C 4H 8O 0 G 0300.00 5000.00 1000.00 1 0.66259856E+01 0.24037426E-01-0.85048041E-05 0.13961984E-08-0.87795283E-13 2 -0.49348359E+04-0.10225971E+02 0.13099357E+01 0.34782715E-01-0.12483845E-04 3 -0.20726512E-08 0.19231736E-11-0.32000645E+04 0.18393772E+02 4 C4H10 C 4H 10O 0 G 0300.00 5000.00 1000.00 1 0.74767122E+01 0.28351745E-01-0.99808667E-05 0.16332101E-08-0.10249437E-12 2 -0.20383525E+05-0.17243061E+02-0.47249255E+00 0.46364300E-01-0.19162337E-04 3 -0.26612175E-08 0.33023280E-11-0.17987465E+05 0.24826550E+02 4 C3H7OH C 3H 8O 1 G 0300.00 5000.00 1000.00 1 0.78695178E+01 0.22170236E-01-0.76477927E-05 0.12332934E-08-0.76598667E-13 2 -0.36669754E+05-0.15247448E+02 0.13337798E+00 0.40273454E-01-0.14728696E-04 3 -0.80114964E-08 0.58863921E-11-0.34506324E+05 0.25219995E+02 4 C2H3CHOZ C 3H 4O 1 G 0300.00 5000.00 1000.00 1 0.54758081E+01 0.20323459E-01-0.91444454E-05 0.17777224E-08-0.12597597E-12 2 -0.11801455E+05-0.32571678E+01 0.32142591E-01 0.27851876E-01-0.13119045E-04 3 0.61531744E-08-0.26709342E-11-0.93820029E+04 0.27982979E+02 4 C3H7CHO C 4H 8O 1 G 0300.00 5000.00 1000.00 1 0.78544631E+01 0.25887879E-01-0.92356704E-05 0.15248637E-08-0.96257942E-13 2 -0.29878918E+05-0.13730366E+02-0.19119226E+01 0.52698199E-01-0.32785865E-04 3 0.67593700E-08 0.11583668E-11-0.27227180E+05 0.36639725E+02 4 C3H5OOHZ C 3H 6O 2 G 0300.00 5000.00 1000.00 1 0.10439779E+02 0.17573746E-01-0.60961356E-05 0.98704911E-09-0.61481954E-13 2 -0.11944713E+05-0.24793179E+02 0.36786113E+01 0.32269310E-01-0.10301906E-04 3 -0.76882758E-08 0.48891334E-11-0.99506963E+04 0.10972757E+02 4 C2H4CHOOOH C 3H 6O 3 G 0300.00 5000.00 1000.00 1 0.12270981E+02 0.16724713E-01-0.53672911E-05 0.82302476E-09-0.49402902E-13 2

311

-0.37788770E+05-0.29148544E+02 0.26266456E+01 0.46026099E-01-0.38194237E-04 3 0.16775585E-07-0.28487234E-11-0.35281090E+05 0.19966557E+02 4 C4H7OOHZ C 4H 8O 2 G 0300.00 5000.00 1000.00 1 0.13162507E+02 0.21643989E-01-0.71929812E-05 0.11303418E-08-0.68989261E-13 2 -0.17694191E+05-0.36459305E+02 0.22901256E+01 0.47590896E-01-0.18961156E-04 3 -0.95546548E-08 0.73198019E-11-0.14679048E+05 0.20296099E+02 4 C3H6CHOOOH C 4H 8O 3 G 0300.00 5000.00 1000.00 1 0.14267727E+02 0.22680208E-01-0.74149721E-05 0.11515231E-08-0.69696541E-13 2 -0.41289266E+05-0.37901749E+02 0.24854505E+01 0.57312340E-01-0.43632172E-04 3 0.16375095E-07-0.19451177E-11-0.38181461E+05 0.22358135E+02 4 C3H5OOHY C 3H 6O 2 G 0300.00 5000.00 1000.00 1 0.10909508E+02 0.16794676E-01-0.57275392E-05 0.91581626E-09-0.56526222E-13 2 -0.12332066E+05-0.27471462E+02 0.51672029E+00 0.51106941E-01-0.47172194E-04 3 0.22034492E-07-0.36731447E-11-0.98368721E+04 0.24594032E+02 4 C2H5COOOH C 3H 6O 3 G 0300.00 5000.00 1000.00 1 0.11428596E+02 0.17910093E-01-0.58774899E-05 0.91505270E-09-0.55473435E-13 2 -0.40523773E+05-0.25254608E+02 0.41114621E+01 0.36034696E-01-0.18766083E-04 3 0.13592378E-08 0.15761134E-11-0.38410105E+05 0.13054103E+02 4 C4H7OOHY C 4H 8O 2 G 0300.00 5000.00 1000.00 1 0.12377043E+02 0.23240978E-01-0.79734837E-05 0.12817828E-08-0.79485734E-13 2 -0.17037293E+05-0.33649040E+02 0.25435202E+01 0.50029602E-01-0.30610132E-04 3 0.52741331E-08 0.16029609E-11-0.14387111E+05 0.17056837E+02 4 C3H7COOOH C 4H 8O 3 G 0300.00 5000.00 1000.00 1 0.14123954E+02 0.23721818E-01-0.79808287E-05 0.12631959E-08-0.77381576E-13 2 -0.46483902E+05-0.38689766E+02 0.10033007E+01 0.60780235E-01-0.42148509E-04 3 0.10570322E-07 0.82954872E-12-0.43011398E+05 0.28640820E+02 4 C3H7OOH C 3H 8O 2 G 0300.00 5000.00 1000.00 1 0.10595881E+02 0.21092908E-01-0.69577177E-05 0.10872773E-08-0.66088445E-13 2 -0.27474047E+05-0.24426392E+02 0.18213568E+01 0.42758811E-01-0.20479554E-04 3 -0.19162016E-08 0.35641871E-11-0.25000381E+05 0.21374474E+02 4 C4H9OH C 4H 10O 1 G 0300.00 5000.00 1000.00 1 0.94385109E+01 0.28290663E-01-0.97171314E-05 0.15629870E-08-0.96942494E-13 2 -0.38791688E+05-0.21847961E+02 0.70391624E-03 0.51434118E-01-0.25048006E-04 3 0.21933105E-09 0.28653735E-11-0.36071867E+05 0.27575392E+02 4 C4H10O C 4H 10O 1 G 0300.00 5000.00 1000.00 1 0.10338789E+02 0.28600262E-01-0.10104396E-04 0.16579825E-08-0.10426815E-12 2 -0.36745551E+05-0.28325302E+02-0.66720688E+00 0.60105029E-01-0.41867042E-04 3 0.14012151E-07-0.12178521E-11-0.33770215E+05 0.28238325E+02 4 C4H10OO C 4H 10O 2 G 0300.00 5000.00 1000.00 1 0.12603670E+02 0.26696790E-01-0.88122661E-05 0.13779865E-08-0.83808537E-13 2 -0.30240355E+05-0.34318184E+02 0.33559802E+01 0.44081770E-01-0.87931503E-05 3 -0.13929200E-07 0.70754257E-11-0.27296576E+05 0.15480649E+02 4 C5H12 C 5H 12O 0 G 0300.00 5000.00 1000.00 1 0.52549806E+01 0.41691124E-01-0.15651747E-04 0.26778380E-08-0.17325166E-12 2 -0.22155322E+05-0.10580750E+01-0.30218682E+00 0.54101773E-01-0.13815486E-04 3 -0.14959753E-07 0.87671545E-11-0.20794248E+05 0.27644793E+02 4 C6H14 C 6H 14O 0 G 0300.00 5000.00 1000.00 1 0.80856771E+01 0.46024326E-01-0.16877226E-04 0.28413987E-08-0.18184004E-12 2 -0.26571869E+05-0.17101089E+02-0.38255847E+00 0.65773375E-01-0.21263440E-04 3 -0.12818359E-07 0.85709165E-11-0.24351697E+05 0.26871195E+02 4 C4H9OOH C 4H 10O 2 G 0300.00 5000.00 1000.00 1 0.13364201E+02 0.26301583E-01-0.87335775E-05 0.13712343E-08-0.83620455E-13 2 -0.33745547E+05-0.38009354E+02 0.83388466E+00 0.60939860E-01-0.39002498E-04 3 0.78341813E-08 0.16028346E-11-0.30397754E+05 0.26467260E+02 4 C3H5OHY C 3H 6O 1 G 0300.00 5000.00 1000.00 1 0.13364201E+02 0.26301583E-01-0.87335775E-05 0.13712343E-08-0.83620455E-13 2 -0.33745547E+05-0.38009354E+02 0.83388466E+00 0.60939860E-01-0.39002498E-04 3 0.78341813E-08 0.16028346E-11-0.30397754E+05 0.26467260E+02 4 C3H5CHOY C 4H 6O 1 G 0300.00 5000.00 1000.00 1 0.13364201E+02 0.26301583E-01-0.87335775E-05 0.13712343E-08-0.83620455E-13 2 -0.33745547E+05-0.38009354E+02 0.83388466E+00 0.60939860E-01-0.39002498E-04 3 0.78341813E-08 0.16028346E-11-0.30397754E+05 0.26467260E+02 4 C4H7OHY C 4H 8O 1 G 0300.00 5000.00 1000.00 1 0.13364201E+02 0.26301583E-01-0.87335775E-05 0.13712343E-08-0.83620455E-13 2 -0.33745547E+05-0.38009354E+02 0.83388466E+00 0.60939860E-01-0.39002498E-04 3 0.78341813E-08 0.16028346E-11-0.30397754E+05 0.26467260E+02 4 C4H8OOY C 4H 8O 2 G 0300.00 5000.00 1000.00 1 0.13364201E+02 0.26301583E-01-0.87335775E-05 0.13712343E-08-0.83620455E-13 2 -0.33745547E+05-0.38009354E+02 0.83388466E+00 0.60939860E-01-0.39002498E-04 3 0.78341813E-08 0.16028346E-11-0.30397754E+05 0.26467260E+02 4 C5H10Y C 5H 10O 0 G 0300.00 5000.00 1000.00 1 0.13364201E+02 0.26301583E-01-0.87335775E-05 0.13712343E-08-0.83620455E-13 2 -0.33745547E+05-0.38009354E+02 0.83388466E+00 0.60939860E-01-0.39002498E-04 3 0.78341813E-08 0.16028346E-11-0.30397754E+05 0.26467260E+02 4 C6H10Y2 C 6H 10O 0 G 0300.00 5000.00 1000.00 1 0.13364201E+02 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3.69757800E+00 6.13519700E-04-1.25884200E-07 1.77528100E-11-1.13643500E-15 2

316

-1.23393000E+03 3.18916600E+00 3.21293600E+00 1.12748600E-03-5.75615000E-07 3 1.31387700E-09-8.76855400E-13-1.00524900E+03 6.03473800E+00 4 H2O H 2O 1 0 0G 300.00 5000.00 1000.00 0 1 2.67214600E+00 3.05629300E-03-8.73026000E-07 1.20099600E-10-6.39161800E-15 2 -2.98992100E+04 6.86281700E+00 3.38684200E+00 3.47498200E-03-6.35469600E-06 3 6.96858100E-09-2.50658800E-12-3.02081100E+04 2.59023300E+00 4 H2O2 H 2O 2 0 0G 300.00 5000.00 1000.00 0 1 4.57316700E+00 4.33613600E-03-1.47468900E-06 2.34890400E-10-1.43165400E-14 2 -1.80069600E+04 5.01137000E-01 3.38875400E+00 6.56922600E-03-1.48501300E-07 3 -4.62580600E-09 2.47151500E-12-1.76631500E+04 6.78536300E+00 4 CO O 1C 1 0 0G 300.00 5000.00 1000.00 0 1 3.02507800E+00 1.44268900E-03-5.63082800E-07 1.01858100E-10-6.91095200E-15 2 -1.42683500E+04 6.10821800E+00 3.26245200E+00 1.51194100E-03-3.88175500E-06 3 5.58194400E-09-2.47495100E-12-1.43105400E+04 4.84889700E+00 4 CO2 O 2C 1 0 0G 300.00 5000.00 1000.00 0 1 4.45362300E+00 3.14016900E-03-1.27841100E-06 2.39399700E-10-1.66903300E-14 2 -4.89669600E+04-9.55395900E-01 2.27572500E+00 9.92207200E-03-1.04091100E-05 3 6.86668700E-09-2.11728000E-12-4.83731400E+04 1.01884900E+01 4 CH2O H 2O 1C 1 0G 300.00 5000.00 1000.00 0 1 2.99560600E+00 6.68132100E-03-2.62895500E-06 4.73715300E-10-3.21251700E-14 2 -1.53203700E+04 6.91257200E+00 1.65273100E+00 1.26314400E-02-1.88816800E-05 3 2.05003100E-08-8.41323700E-12-1.48654000E+04 1.37848200E+01 4 C C 1 0 0 0G 300.00 5000.00 1000.00 0 1 2.60208700E+00-1.78708100E-04 9.08704100E-08-1.14993300E-11 3.31084400E-16 2 8.54215400E+04 4.19517700E+00 2.49858500E+00 8.08577700E-05-2.69769700E-07 3 3.04072900E-10-1.10665200E-13 8.54587800E+04 4.75345900E+00 4 H H 1 0 0 0G 300.00 5000.00 1000.00 0 1 2.50000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 2 2.54716300E+04-4.60117600E-01 2.50000000E+00 0.00000000E+00 0.00000000E+00 3 0.00000000E+00 0.00000000E+00 2.54716300E+04-4.60117600E-01 4 CH H 1C 1 0 0G 300.00 5000.00 1000.00 0 1 2.19622300E+00 2.34038100E-03-7.05820100E-07 9.00758200E-11-3.85504000E-15 2 7.08672300E+04 9.17837300E+00 3.20020200E+00 2.07287600E-03-5.13443100E-06 3 5.73389000E-09-1.95553300E-12 7.04525900E+04 3.33158800E+00 4 CH2 H 2C 1 0 0G 250.00 4000.00 1000.00 0 1 3.63640800E+00 1.93305700E-03-1.68701600E-07-1.00989900E-10 1.80825600E-14 2 4.53413400E+04 2.15656100E+00 3.76223700E+00 1.15981900E-03 2.48958500E-07 3 8.80083600E-10-7.33243500E-13 4.53679100E+04 1.71257800E+00 4 CH2(S) H 2C 1 0 0G 300.00 5000.00 1360.00 0 1 3.09732461E+00 2.80331155E-03-7.10881104E-07 8.36924323E-11-3.81270428E-15 2 4.95090024E+04 4.31246006E+00 3.32929383E+00 2.26625413E-03-2.38920714E-07 3 -1.04565889E-10 2.51400070E-14 4.94285310E+04 3.06576550E+00 4 CH3 H 3C 1 0 0G 300.00 5000.00 1000.00 0 1 2.84405200E+00 6.13797400E-03-2.23034500E-06 3.78516100E-10-2.45215900E-14 2 1.64378100E+04 5.45269700E+00 2.43044300E+00 1.11241000E-02-1.68022000E-05 3 1.62182900E-08-5.86495300E-12 1.64237800E+04 6.78979400E+00 4 C2H3 H 3C 2 0 0G 300.00 5000.00 1000.00 0 1 5.93346800E+00 4.01774600E-03-3.96674000E-07-1.44126700E-10 2.37864400E-14 2 3.18543500E+04-8.53031300E+00 2.45927600E+00 7.37147600E-03 2.10987300E-06 3 -1.32164200E-09-1.18478400E-12 3.33522500E+04 1.15562000E+01 4 H2CCCH H 3C 3 0 0G 300.00 4000.00 1000.00 0 1 8.83104700E+00 4.35719500E-03-4.10906700E-07-2.36872300E-10 4.37652000E-14 2 3.84742000E+04-2.17791900E+01 4.75420000E+00 1.10802800E-02 2.79332300E-07 3 -5.47921200E-09 1.94962900E-12 3.98888300E+04 5.85454900E-01 4 O O 1 0 0 0G 300.00 5000.00 1000.00 0 1 2.54206000E+00-2.75506200E-05-3.10280300E-09 4.55106700E-12-4.36805200E-16 2 2.92308000E+04 4.92030800E+00 2.94642900E+00-1.63816600E-03 2.42103200E-06 3 -1.60284300E-09 3.89069600E-13 2.91476400E+04 2.96399500E+00 4 OH H 1O 1 0 0G 300.00 5000.00 1000.00 0 1 2.88273000E+00 1.01397400E-03-2.27687700E-07 2.17468400E-11-5.12630500E-16 2 3.88688800E+03 5.59571200E+00 3.63726600E+00 1.85091000E-04-1.67616500E-06 3 2.38720300E-09-8.43144200E-13 3.60678200E+03 1.35886000E+00 4 HO2 H 1O 2 0 0G 300.00 5000.00 1000.00 0 1 4.07219100E+00 2.13129600E-03-5.30814500E-07 6.11226900E-11-2.84116500E-15 2 -1.57972700E+02 3.47602900E+00 2.97996300E+00 4.99669700E-03-3.79099700E-06 3 2.35419200E-09-8.08902400E-13 1.76227400E+02 9.22272400E+00 4 HCO H 1O 1C 1 0G 300.00 5000.00 1000.00 0 1 3.55727100E+00 3.34557300E-03-1.33500600E-06 2.47057300E-10-1.71385100E-14 2 3.91632400E+03 5.55229900E+00 2.89833000E+00 6.19914700E-03-9.62308400E-06 3 1.08982500E-08-4.57488500E-12 4.15992200E+03 8.98361400E+00 4 HCCO H 1O 1C 2 0G 300.00 4000.00 1000.00 0 1 6.75807300E+00 2.00040000E-03-2.02760700E-07-1.04113200E-10 1.96516500E-14 2 1.90151300E+04-9.07126200E+00 5.04796500E+00 4.45347800E-03 2.26828300E-07 3 -1.48209500E-09 2.25074200E-13 1.96589200E+04 4.81843900E-01 4 N2 N 2 0 0 0G 300.00 5000.00 1000.00 0 1 2.92664000E+00 1.48797700E-03-5.68476100E-07 1.00970400E-10-6.75335100E-15 2

317

-9.22797700E+02 5.98052800E+00 3.29867700E+00 1.40824000E-03-3.96322200E-06 3 5.64151500E-09-2.44485500E-12-1.02090000E+03 3.95037200E+00 4 AR AR 1 0 0 0G 300.00 5000.00 1000.00 0 1 2.50000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 2 -7.45375000E+02 4.36600100E+00 2.50000000E+00 0.00000000E+00 0.00000000E+00 3 0.00000000E+00 0.00000000E+00-7.45375000E+02 4.36600100E+00 4 CN C 1N 1 0 0G 300.00 5000.00 1000.00 0 1 3.72012000E+00 1.51835100E-04 1.98738100E-07-3.79837100E-11 1.32823000E-15 2 5.11162600E+04 2.88859700E+00 3.66320400E+00-1.15652900E-03 2.16340900E-06 3 1.85420800E-10-8.21469500E-13 5.12811800E+04 3.73901600E+00 4 HCN H 1C 1N 1 0G 300.00 4000.00 1000.00 0 1 3.42645700E+00 3.92419000E-03-1.60113800E-06 3.16196600E-10-2.43285000E-14 2 1.48555200E+04 3.60779500E+00 2.41778700E+00 9.03185600E-03-1.10772700E-05 3 7.98014100E-09-2.31114100E-12 1.50104400E+04 8.22289100E+00 4 N N 1 0 0 0G 300.00 5000.00 1000.00 0 1 2.45026800E+00 1.06614600E-04-7.46533700E-08 1.87965200E-11-1.02598400E-15 2 5.61160400E+04 4.44875800E+00 2.50307100E+00-2.18001800E-05 5.42052900E-08 3 -5.64756000E-11 2.09990400E-14 5.60989000E+04 4.16756600E+00 4 NH H 1N 1 0 0G 300.00 5000.00 1000.00 0 1 2.76024900E+00 1.37534600E-03-4.45191400E-07 7.69279200E-11-5.01759200E-15 2 4.20782800E+04 5.85719900E+00 3.33975800E+00 1.25300900E-03-3.49164600E-06 3 4.21881200E-09-1.55761800E-12 4.18504700E+04 2.50718100E+00 4 NO O 1N 1 0 0G 300.00 5000.00 1000.00 0 1 3.24543500E+00 1.26913800E-03-5.01589000E-07 9.16928300E-11-6.27541900E-15 2 9.80084000E+03 6.41729400E+00 3.37654200E+00 1.25306300E-03-3.30275100E-06 3 5.21781000E-09-2.44626300E-12 9.81796100E+03 5.82959000E+00 4 HNO H 1O 1N 1 0G 300.00 5000.00 1000.00 0 1 3.61514400E+00 3.21248600E-03-1.26033700E-06 2.26729800E-10-1.53623600E-14 2 1.06619100E+04 4.81026400E+00 2.78440300E+00 6.60964600E-03-9.30022300E-06 3 9.43798000E-09-3.75314600E-12 1.09187800E+04 9.03562900E+00 4 NH2 H 2N 1 0 0G 300.00 5000.00 1000.00 0 1 2.96131100E+00 2.93269900E-03-9.06360000E-07 1.61725700E-10-1.20420000E-14 2 2.19197700E+04 5.77787800E+00 3.43249300E+00 3.29954000E-03-6.61360000E-06 3 8.59094700E-09-3.57204700E-12 2.17722800E+04 3.09011100E+00 4 H2NO H 2O 1N 1 0G 300.00 4000.00 1500.00 0 1 5.67334600E+00 2.29883700E-03-1.77444600E-07-1.10348200E-10 1.85976200E-14 2 5.56932500E+03-6.15354000E+00 2.53059000E+00 8.59603500E-03-5.47103000E-06 3 2.27624900E-09-4.64807300E-13 6.86803000E+03 1.12665100E+01 4 NCO O 1C 1N 1 0G 300.00 4000.00 1400.00 0 1 6.07234600E+00 9.22782900E-04-9.84557400E-08-4.76412300E-11 9.09044500E-15 2 1.35982000E+04-8.50729300E+00 3.35959300E+00 5.39323900E-03-8.14458500E-07 3 -1.91286800E-09 7.83679400E-13 1.46280900E+04 6.54969400E+00 4 N2O O 1N 2 0 0G 300.00 5000.00 1000.00 0 1 4.71897700E+00 2.87371400E-03-1.19749600E-06 2.25055200E-10-1.57533700E-14 2 8.16581100E+03-1.65725000E+00 2.54305800E+00 9.49219300E-03-9.79277500E-06 3 6.26384500E-09-1.90182600E-12 8.76510000E+03 9.51122200E+00 4 NO2 O 2N 1 0 0G 300.00 5000.00 1000.00 0 1 4.68285900E+00 2.46242900E-03-1.04225900E-06 1.97690200E-10-1.39171700E-14 2 2.26129200E+03 9.88598500E-01 2.67060000E+00 7.83850100E-03-8.06386500E-06 3 6.16171500E-09-2.32015000E-12 2.89629100E+03 1.16120700E+01 4 N2H2 H 2N 2 0 0G 300.00 5000.00 1000.00 0 1 3.37118500E+00 6.03996800E-03-2.30385400E-06 4.06278900E-10-2.71314400E-14 2 2.41817200E+04 4.98058500E+00 1.61799900E+00 1.30631200E-02-1.71571200E-05 3 1.60560800E-08-6.09363900E-12 2.46752600E+04 1.37946700E+01 4 HOCN H 1O 1C 1N 1G 300.00 4000.00 1400.00 0 1 6.02211200E+00 1.92953000E-03-1.45502900E-07-1.04581100E-10 1.79481400E-14 2 -4.04032100E+03-5.86643300E+00 3.78942400E+00 5.38798100E-03-6.51827000E-07 3 -1.42016400E-09 5.36796900E-13-3.13533500E+03 6.66705200E+00 4 H2CN H 2C 1N 1 0G 300.00 4000.00 1000.00 0 1 5.20970300E+00 2.96929100E-03-2.85558900E-07-1.63555000E-10 3.04325900E-14 2 2.76771100E+04-4.44447800E+00 2.85166100E+00 5.69523300E-03 1.07114000E-06 3 -1.62261200E-09-2.35110800E-13 2.86378200E+04 8.99275100E+00 4 NNH H 1N 2 0 0G 250.00 4000.00 1000.00 0 1 4.41534200E+00 1.61438800E-03-1.63289400E-07-8.55984600E-11 1.61479100E-14 2 2.78802900E+04 9.04288800E-01 3.50134400E+00 2.05358700E-03 7.17041000E-07 3 4.92134800E-10-9.67117000E-13 2.83334700E+04 6.39183700E+00 4 NH3 H 3N 1 0 0G 300.00 5000.00 1000.00 0 1 2.46190400E+00 6.05916600E-03-2.00497700E-06 3.13600300E-10-1.93831700E-14 2 -6.49327000E+03 7.47209700E+00 2.20435200E+00 1.01147600E-02-1.46526500E-05 3 1.44723500E-08-5.32850900E-12-6.52548800E+03 8.12713800E+00 4 N2H3 H 3N 2 0 0G 300.00 5000.00 1000.00 0 1 4.44184600E+00 7.21427100E-03-2.49568400E-06 3.92056500E-10-2.29895000E-14 2 1.66422100E+04-4.27520500E-01 3.17420400E+00 4.71590700E-03 1.33486700E-05 3 -1.91968500E-08 7.48756400E-12 1.72727000E+04 7.55722400E+00 4 C2N2 C 2N 2 0 0G 300.00 5000.00 1000.00 0 1 6.54800300E+00 3.98470700E-03-1.63421600E-06 3.03859700E-10-2.11106900E-14 2

318

3.49071600E+04-9.73579000E+00 4.26545900E+00 1.19225700E-02-1.34201400E-05 3 9.19229700E-09-2.77894200E-12 3.54788800E+04 1.71321200E+00 4 HNCO H 1O 1C 1N 1G 300.00 4000.00 1400.00 0 1 6.54530700E+00 1.96576000E-03-1.56266400E-07-1.07431800E-10 1.87468000E-14 2 -1.66477300E+04-1.00388000E+01 3.85846700E+00 6.39034200E-03-9.01662800E-07 3 -1.89822400E-09 7.65138000E-13-1.56234300E+04 4.88249300E+00 4 NO3 121286N 1O 3 G 0300.00 5000.00 1000.00 1 0.07120307E+02 0.03246228E-01-0.01431613E-04 0.02797053E-08-0.02013008E-12 2 0.05864479E+05-0.01213730E+03 0.01221076E+02 0.01878797E+00-0.01344321E-03 3 0.01274601E-07 0.01354060E-10 0.07473144E+05 0.01840203E+03 4 END