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STUDIES ON PREPARATION AND
CHARACTERIZATION OF REGENERATED
PAKISTANI WASTE OIL-BIODIESEL BLENDS
A thesis presented for the degree of
Doctor of Philosophy in
Chemistry
at Bahaudin Zakariya University, Multan
Muhammad Qasim M.Sc. (SALU), M.Phil (SALU)
Institute of Chemical Sciences
Bahaudin Zakariya University
Multan, Pakistan
2018
i
“My Lord ! Grant me the power and ability that I may be grateful for Your
favour which You have bestowed upon me and upon my parents, and that I
may do righteous good deeds, such as please You, and make my offspring
good. Truly, I have turned to You in repentance, and truly, I am one of the
Muslims (submitting myself to Your will)” (15) Surah Al-Ahqaf, part26, Al-
Quran.
ii
Dedication
I would like to dedicate this thesis to my loving mother, sweet father, beloved son
Muhammad Usman, beloved brothers Mr. Muhammad Asim Khan and Mr.
Muhammad Zahid Khan for their untiring patience and enjoyable companionship.
iii
Declaration
I, hereby, declare that this thesis has been composed by myself and is based on work done by
myself. It has not been accepted in any previous application for a higher degree. All verbatim
extracts have been distinguished by quotation marks and the sources of the information have
been specifically acknowledged.
Muhammad Qasim
iv
Certificate
It is certified that Mr. Muhammad Qasim has completed his doctoral research work as per Rules
and Regulations for higher degree. It is also certified that the research work embodied in this
thesis entitled “STUDIES ON PREPARATION AND CHARACTERIZATION OF
REGENERATED PAKISTANI WASTE OIL-BIODIESEL BLENDS” has been carried out by
Mr. Muhammad Qasim under our supervision and is worth presenting to Bahauddin Zakariya
University, Multan for the award of Ph.D degree.
Supervisor(s):
1. Prof. Dr. Tariq Mahmood Ansari
Ph.D (UK), FCSP, FPFS, MRSC (UK),
Professor of Analytical Chemistry,
Institute of Chemical Sciences,
Bahaudin Zakariya University, Multan, Pakistan.
2. Dr. Mazhar Hussain
Ph.D (Germany),
Associate Professor of Organic Chemistry,
Institute of Chemical Sciences,
Bahaudin Zakariya University, Multan, Pakistan.
.
v
Acknowledgements
I wish to express my profound gratitude to my sincere and esteemed Supervisors Prof. Dr.Tariq
Mahmood Ansari FRSC, Professor of Analytical Chemistry & Dean Faculty of Science,
Institute of Chemical Sciences, Bahaudin Zakariya University, Multan, Pakistan and Dr.
Mazhar Hussain, Associate Professor of Organic Chemistry, Institute of Chemical Sciences,
Bahaudin Zakariya University, Multan, Pakistan for their thought provoking guidance,
inestimable counsel, invaluable help and fabulous supervision during my doctoral research.
I feel highly privileged in taking the opportunity to express my heartfelt gratitude to Mr.
Muhammad Shafeeq, Director General & Malik Sagheer Hussain, Chief Chemist,
Hydrocarbon Development Institute of Pakistan (HDIP) Islamabad, for their nice cooperation
during my research work.
I am grateful to Dr. Farzana Mahmood, Director, Intstitute of Chemical Sciences, Bahaudin
Zakariya University, Multan, for her kind attitude and help to complete this work.
I wish to record my sincere thanks to Prof. Dr. Mushtaq Ali Jakhrani, Institute of Chemistry,
Shah Abdul Latif University, Khairpur, Pakistan, for his generous support cooperation and
prayers.
Last, but not least, no acknowledgement could ever be adequate to express my indebtedness and gratitude
to my caring father, loving mother, adorable children, dear brothers and affectionate sisters for their
understanding, support and encouragement during this study. I salute my great spiritual father (Hazoor
Saein) for his countless blessings and kind prayers that are precious assets of my life.
Muhammad Qasim
vi
Summary
Global warming due to fossil fuel emissions, depletion of petroleum product reserves, population
growth and crude oil price hikes have stimulated researchers to search for economical and
environment friendly alternative energy resources. This study firstly reports the development of a
novel, cheap, easy and environmental friendly regeneration method of waste automotive oil.
Secondly, efforts were made to convert Pakistani waste oils such as waste engine oil, waste
transformer oil, waste tyre pyrolysis oil and waste cooking oil into biodiesel and biodiesel-diesel
fuel blends to be used in diesel engines without any engine modification.
A new method was developed to regenerate waste automotive engine oils into valuable base oil
using cheaply available Rice Husk Ash (RHA) as raw material. Optimum results were observed
only with 6% activated RHA. The advantage of using an activated rice husk ash is that it does
not react with base oils and involves use of only 1% acetic acid as compared to conventional acid
clay method involving the use of 6-8% Conc. H2SO4 which is harmful to the environment.
Another advantage of using acetic acid is that it does not emit poisonous gases like sulfur dioxide
to the atmosphere.
Efforts were made to prepare biodiesel like fuel blends derived from pretreated waste engine oil,
waste transformer oil, waste tyre pyrolysis oil and waste cooking oil. Experimental investigations
on these Pakistani waste oils were carried out in a 5.5kW four-stroke single-cylinder water-
cooled direct-injection diesel engine for combustion, performance and emission characteristics.
Results obtained were compared with those of petroleum diesel. All the fuel blends run in the
diesel engine have shown slightly higher fuel consumptions and shorter ignition delays in
comparison to petroleum diesel. The engine was successfully operated with waste oil derived
biodiesel fuel blends without engine failure but the best performance was observed with CFB10,
vii
BLF15, BLF20, FMWO10, WCOB10 and WCOB15 biodiesel fuel blends. Biodiesel blends
derived from regenerated waste engine oils have shown significantly lower HC, CO and smoke
emissions as compared to petroleum based diesel. Biodiesel fuel blends derived from waste
transformer oil have indicated lower HC, CO and smoke emissions as 10.92-31.17%, 3.80-6.32%
and 1.39-5.21% respectively in comparison to those of petroleum diesel. Fuel blends derived
from waste tyre pyrolysis oil have shown 3.12-15.62%, 16.5-33.2% and 1.83 - 4.5% lesser CO,
HC and smoke emissions compared to petroleum diesel fuel. Similarly, biodiesel fuel blends
derived from waste cooking oil have shown significantly reduced pollutant emissions.
All the biodiesel-diesel fuel blends derived from waste oils mentioned above were characterized
by FTIR and the results were compared with those of petroleum diesel. Like petroleum diesel,
the obtained FTIR analysis results also confirmed the presence of saturated alkanes in the
investigated biodiesel fuel blends.
Biodiesels derived from regenerated waste oils and their blends were characterized for physico-
chemical properties using ASTM (American Society for Testing and Material) standard methods
and the results were compared with petroleum diesel. Analysis results were found within the
permissible limits of biodiesel fuel as specified by European (EN14214) and American (ASTM
6751) standards.
Current research demonstrates the beneficial and environment friendly conversion of waste oils
into useful commodity i.e. biodiesel to be used as alternative fuels for diesel engines. On the
whole, this will reduce hazardous waste oil disposal problems, minimize environmental issues
and boost the economy of Pakistan by minimizing its dependence on foreign origin crude oil
reserves for mineral diesel fuel.
viii
TABLE OF CONTENTS
DEDICATION II
DECLARATION III
CERTIFICATE IV
ACKNOWLEDGEMENTS V
SUMMARY VI
TABLE OF CONTENTS VIII
LIST OF TABLES XIII
LIST OF FIGURES XV
ABBREVIATIONS XIX
CHAPTER 1 1
GENERAL INTRODUCTION AND LITERATURE REVIEW ......................................................... 1 1.1 Introduction 1
1.1.1 Worldwide Energy Consumption 4 1.1.2 Energy Scenario in Pakistan 5
1.2 Literature Review 7 1.2.1 Renewable Energy 7 1.2.2 Search for Alternative Fuels 8 1.2.3 Engine Tribology 9 1.2.4 Metal Surfaces 9
1.2.4.1 Layers of Metal Surface 10 1.2.4.2 Physisorbed Layer 10 1.2.4.3 Chemisorbed Layer 10 1.2.4.4 Oxide Layer 10 1.2.4.5 Beilby Layer 11 1.2.4.6 Deformed Layer 11
1.2.5 Friction and Wear 11 1.2.6 Science of Lubricating Oil 12
1.2.6.1 Composition of Lubricating Oil 13 1.2.6.2 Lubricant Base Oils 13 1.2.6.3 Lubricant Additives 13
1.2.6.3.1 Antioxidants 14 1.2.6.3.2 Antiwear Additives 14 1.2.6.3.3 Viscosity Index (VI) Stabilizers 14 1.2.6.3.4 Detergents and Dispersing Agents 15 1.2.6.3.5 Antifoaming Additives 15 1.2.6.3.6 Pour Point Improving Additives 15 1.2.6.3.7 Anticorrosion Additives 16
1.2.7 Waste Lubricants 16 1.2.7.1 Composition of Waste Lubricants 16 1.2.7.2 Compounds of Carbon and Hydrogen 16 1.2.7.3 Additives for Lubricants and Fuels 17 1.2.7.4 Polycyclic Aromatic Hydrocarbons (PAHs) 19 1.2.7.5 Water Contents 20 1.2.7.6 Trace Metals and Metallic Fragments 20 1.2.7.7 Sand and Dirt 20
1.2.8 Toxic Effects of Waste Lubricating Oil 20 1.2.8.1 Toxic Effects on Human Health 20 1.2.8.2 Toxic Effects on Animals 21
1.2.9 Adsorption 21 1.2.9.1 Introduction 21
ix
1.2.9.2 Physisorption and Chemisorption 22 1.2.9.3 Adsorbents 23
1.2.9 Alternative Fuels 23 1.2.9.1 Vegetable Oils 23 1.2.9.2 Esters of Vegetable Oils 24 1.2.9.3 Alcohols 25 1.2.9.4 Pyrolysis Oils 25 1.2.9.5 Waste Oils 26
1.2.9.5.1 Waste Engine Oil 26 1.2.9.5.2 Waste Plastic Oil 26 1.2.9.5.3 Waste Transformer Oil 27 1.2.9.5.4 Waste Tyre Pyrolysis Oil 28 1.2.9.5.5 Waste Cooking Oil 29
1.2.10 Used Oil Regeneration Technologies 29 1.2.10.1 Vacuum Distillation 29 1.2.10.2 Atmospheric Distillation 30 1.2.10.3 Adsorption Process 30 1.2.10.4 Sulfuric Acid Process 30 1.2.10.5 Hydro Processing 31 1.2.10.6 Centrifugation 32 1.2.10.7 Propane Extraction 32 1.2.10.8 Thin Film Evaporation 33
1.2.11 Refining Processes of Mineral Base Oils 33 1.2.11.1 Separation Technology 33 1.2.11.2 Conversion Technology 34
1.2.12 Biodiesel and Its Blends 36 1.2.12.1 Biodiesel 36 1.2.12.2 History of Biodiesel 36 1.2.12.3 Beneficial Aspects of Biodiesel 38 1.2.12.4 Harmful Aspects of Biodiesel 39 1.2.12.5 Transestrerification Process 40
1.2.12.5.1 Mixing of Alcohol and Catalyst 42 1.2.12.5.2 Reaction 42 1.2.12.5.3 Separation of Glycerin and Biodiesel 42 1.2.12.5.4 Removal of Alcohol 42 1.2.12.5.5 Glycerin Neutralization 43 1.2.12.5.6 Methyl Ester Washing 43
1.2.12.6 Sources of Biodiesel in Different Countries 43 1.2.12.7 Waste Frying Oil as a Biodiesel Feedstock 45 1.2.12.8 Frying Process of Vegetable Oils 46
1.2.12.8.1 Oxidative Effects 46 1.2.12.8.2 Hydrolytic Effects 46 1.2.12.8.3 Thermal Effects 46
1.2.12.9 Vegetable Oils Used in Present Research 47 1.2.12.9.1 Sunflower (Helianthus Annuus) Oil 47 1.2.12.9.2 Soybean Oil 48 1.2.12.9.3 Corn Oil (Maize Oil) 49 1.2.12.9.4 Canola Oil 50
1.2.12.10 Biodiesel Blends 52 1.2.12.10.1 B100 Blend 52 1.2.12.10.2 B20 Blend 52 1.2.12.10.3 B5 Blend 53 1.2.12.10.4 B2 Blend 53
1.2.12.11 Emission Characteristics of Biodiesel 53 1.2.12.12 Emission Characteristics of Biodiesel Blends 54
1.2.12.12.1 Particulate Matter (PM) 54 1.2.12.12.2 Hydrocarbons (HC) 54 1.2.12.12.3 Nitrogen Oxides (NOx) 54 1.2.12.12.4 Smog Formation 55 1.2.12.12.5 Carbon Monoxides 55
1.3 Aims and Objectives 55
x
CHAPTER 2 57
MATERIALS AND METHODS ........................................................................................................... 57 2.1 Equipment and Chemicals 57
2.1.1 Equipment 57 2.1.2 Chemicals and Glassware 58
2.2 Samples Collection 59 2.2.1 Pretreatment 60 2.2.2 Waste Rice Husk 60
2.3 Regeneration of Waste Automotive Oil 61 2.3.1 Rice Husk Ash Method (Present Research) 61
2.3.1.1 Incineration of Rice Husk 61 2.3.1.2 Activation of Incinerated Rice Husk 61 2.3.1.3 Pretreatment of Waste Engine Oil 62 2.3.1.4 Atmospheric Distillation 62 2.3.1.5 Activated Rice Husk Ash Treatment 62 2.3.1.6 Centrifugation 62
2.3.2 Acid/Clay Treatment (Existing Method) 63 2.3.3 Distillation/Clay Treatment (Existing Method) 64
2.4 Fuel Blends Raw Material 64 2.4.1 Production of Biodiesel from Waste Canola Oil 64
2.4.1.1 Synthesis of Sodium Methoxide 64 2.4.1.2 Transesterification Process 64 2.4.1.3 Separation of Biodiesel 65 2.4.1.4 Purification of Biodiesel 65
2.4.2 Production of Biodiesel from Waste Corn, Soybean and Sunflower Oil 66 2.4.3 Transesterification of Waste Transformer Oil 67 2.4.4 Catalytic Cracking of Waste Engine Oil 67 2.4.5 Waste Tyre Pyrolysis Oil. 68
2.5 Investigations on a Diesel Engine with Various Fuel Blends 69 2.5.1 Engine Setup 69
2.5.1.1 Exhaust Gas Measurements 72 2.5.2 Fuel Blends Derived from Waste Oils 74
2.5.2.1 Waste Engine Oil Biodiesel Blends 75 2.5.2.2 Waste Transformer Oil-Biodiesel Blends 76 2.5.2.3 Waste Tyre Pyrolysis Oil-Biodiesel Blends 76 2.5.2.4 Waste Cooking Oil Biodiesel-Diesel Blends 77
2.6 Fuel Properties 78 2.6.1 Kinematic Viscosity 78 2.6.2 Density or Specific Gravity 79 2.6.3 Calorific Value 80 2.6.4 Flash Point 82 2.6.5 Acid Value 83 2.6.6 Pour Point 84 2.6.7 Water Contents 85 2.6.8 Ash Contents 86 2.6.9 Conradson Carbon Residue 86 2.6.10 Distillation 87 2.6.11 Sulphur Contents 88 2.6.12 Cetane Index 88
2.7 Infrared Spectroscopy 89 2.7.1 Background 89 2.7.2 FTIR Spectrometer 90 2.7.3 FTIR Analysis 91
CHAPTER-3 92
RESULTS AND DISCUSSION ............................................................................................................. 92 3.1 General 92 3.2 Waste Automotive Oil 92 3.3 Recycling of Waste Automotive Oil Using Rice Husk Ash 93
xi
3.4 Comparison with Acid/Clay and Distillation Clay Methods. 95 3.5 Preparation of Biodiesel from Waste Cooking Oil 99 3.5 FT-IR Analysis 102 3.6. Waste Engine Oil and its Blends 112
3.6.1 FTIR Analysis 112 3.6.2 Fuel properties 114 3.6.3 Combustion Analysis 118
3.6.3.1 Ignition Delay 118 3.6.3.2 Heat Release Rate (HRR) 119 3.6.3.3 Maximum Cylinder Pressure 120
3.6.4 Engine Performance 121 3.6.4.1 Brake Specific Fuel Consumption 121 3.6.4.2 Brake Thermal Efficiency 122 3.6.4.3 Exhaust Gas Temperature 123
3.6.5 Engine Emissions 125 3.6.5.1 Hydrocarbon Emission 125 3.6.5.2 Carbon Monoxide Emission 126 3.6.5.3 Nitrogen Oxide Emission 127 3.6.5.4 Smoke Opacity 127
3.7 Waste Transformer Oil and its Blends 128 3.7.1 FT-IR Analysis 128 3.7.2 Fuel Properties 130 3.7.3 Combustion Characteristics 134
3.7.3.1 Ignition Delay 134 3.7.3.2 Heat Release Rate 135 3.7.3.3 Maximum Cylinder Pressure 135
3.7.4 Engine Performance 136 3.7.4.1 Brake Specific Fuel Consumption (BSFC) 136 3.7.4.2 Brake Thermal Efficiency (BTE) 137 3.7.4.3 Exhaust Gas Temperature (EGT) 138
3.7.5 Engine Emissions 139 3.7.5.1 Hydrocarbons (HC) 139 3.7.5.2 Carbon Monoxide (CO) 140 3.7.5.3 Nitrogen Oxide (NOx) 141 3.7.5.4 Smoke Opacity 142
3.8 Waste Tyre Pyrolysis Oil and its Blends 144 3.8.1 FTIR Analysis 144 3.8.2 Fuel Properties 146 3.8.3 Combustion Characteristics 149
3.8.3.1 Ignition Delay 149 3.8.3.2 Heat Release Rate (HRR) 150 3.8.3.3 Maximum Cylinder Pressure 151
3.8.4 Engine Performance 152 3.8.4.1 Brake Specific Fuel Consumption 152 3.8.4.2 Brake Thermal Efficiency 153 3.8.4.3 Exhaust Gas Temperature 154
3.8.5 Emissions 155 3.8.5.1 Hydrocarbons 155 3.8.5.2 Carbon Monoxide 156 3.8.5.3 Nitrogen Oxide 157 3.8.5.4 Smoke Opacity 158
3.9 Waste Cooking Oil Biodiesel and its Blends 160 3.9.1 FTIR Analysis 160 3.9.2 Fuel Properties 162 3.9.3 Combustion Characteristics 165
3.9.3.1 Ignition Delay 165 3.9.3.2 Heat Release Rate 166 3.9.3.3 Maximum Cylinder Pressure 167
3.9.4 Engine Performance 168 3.9.4.1 Brake Specific Fuel Consumption 168 3.9.4.2 Brake Thermal Efficiency 169
xii
3.9.4.3 Exhaust Gas Temperature 170 3.9.5 Engine Emissions 171
3.9.5.1 Hydrocarbons 171 3.9.5.2 Carbon Monoxide Emission 172 3.9.5.3 Nitrogen Oxide Emission 173 3.9.5.4 Smoke Opacity 174
CONCLUSIONS 176
FUTURE RECOMMENDATIONS 180
REFERENCES 181
APPENDIX-I ........................................................................................................................................ 191 AUTHOR’S ACADEMIC AND RESEARCH PROFILE ................................................................................ 191 APPENDIX-II ...................................................................................................................................... 193 PRESENT WORK RESEARCH PUBLICATIONS ......................................................................................... 193
xiii
LIST OF TABLES
Table 1.1 Energy consumption per capita 2007 5
Table 1.2 Renewable energy potentials for Pakistan 8
Table 1.3 Commonly Found wear types at the Surface of Metals and Alloys 12
Table 1.4 General Characteristics of Diesel and Gasoline 17
Table 1.5 Additives Used for Gasoline Fuel 18
Table 1.6 Additives Used for Diesel Fuel 18
Table 1.7 Polyaromatic hydrocarbons in waste lubricating oils 19
Table 1.8 Important Definitions related to adsorption 21
Table 1.11 Most commonly found re-refineable and not re-refineable oils by the Canadian 31
Table 1.12 Sources of biodiesel in different countries. 44
Table 1.13 Characteristics of Sunflower Oil (SF Oil) 48
Table 1.14 Physical properties of soybean oil. 49
Table 1.15 Physical Properties of Corn Oil 50
Table 1.16 Physical properties of canola oil 51
Table 1.17 Commonly found biodiesel blends emissions for a heavy duty engine 54
Table 2.1 List of chemicals used during the research work. 59
Table 2.2 Technical specifications of the engine used during the research work. 71
Table 2.3 CFB and its blends composition 76
Table 2.4 BLF and its blends Composition 76
Table 2.5 Composition of FMWO and its blends 77
Table 2.6 Petroleum Diesel and biodiesel blends Composition 77
Table 3.1 Waste Automotive Oil Characteristics 92
Table 3.2 Regenerated Oil Characteristics (RHA + 1% H2SO4). 94
Table 3.3 Regenerated Oil Characteristics (RHA + 1% CH3COOH). 94
Table 3.4 Characteristics of the oil re-refined with different techniques. 96
Table 3.5 Characteristics of the oil re-refined with different techniques. 97
Table 3.6 Physico-chemical properties of waste cooking oil methyl esters (biodiesel). 100
Table 3.7 Comparison of calorific value, cetane number and distillation of waste cooking oil methyl esters with that
of diesel. 100
Table 3.8 FT-IR data of WSFO 104
Table 3.9 FT-IR data of ME-WSFO. 105
Table 3.10 FT-IR data of WCRO. 106
Table 3.11 FT-IR data of ME-WCRO. 107
Table 3.12 FT-IR data of WSBO. 108
Table 3.13 FT-IR data of ME-WSBO. 109
xiv
Table 3.14 FT-IR data of WCAO. 110
Table 3.15 FT-IR data of ME-WCAO. 111
Table 3.16 FTIR results for diesel and CFB fuel. 113
Table 3.17 Comparison of fuel properties of CFB fuels with biodiesel fuel standards specs. 114
Table 3.18 Combustion, performance and emission values at various engine loads. 124
Table 3.19 FTIR results of diesel and BLF fuel. 129
Table 3.20 Comparison of fuel properties of BLF fuels with biodiesel fuel standards specs. 130
Table 3.21 Results of combustion, performance, and emission characteristics of the engine fuelled with biodiesel
like fuel (BLF) blends. 143
Table 3.22 FTIR results for diesel and FMWO 145
Table 3.23 Comparison of fuel properties of FMWO blends with biodiesel fuel standards. 146
Table 3.24 Results of combustion, performance, and emission characteristics of the engine fuelled with the fuel
blends derived from waste tyre pyrolysis oil. 159
Table 3.25 FTIR Data for diesel and WCOB. 161
Table 3.26 Comparison of fuel properties of WCOB blends with biodiesel fuel standards. 162
Table 3.27 Results of combustion, performance, and emission characteristics of the engine fuelled with waste
cooking oil biodiesel blends. 171
xv
LIST OF FIGURES
Figure 1.1 Supply demand gap in Pakistan 2002-2030 6
Figure 1.2 Photographic view of cross section of a hypothetical porous grain showing various types of pores: closed
(C), blind (B), through (T), interconnected (I), together with some roughness (R). 22
Figure 1.3 Simplified Flow Diagram of Separation System 34
Figure 1.4 Simplified Flow Diagram of Conversion System. 35
Figure 1.3 Procedure of manufacturing biodiesel through transestrerification reaction 41
Figure 1.4 Transestrerification reaction of triglycerides and methanol in manufacturing of Biodiesel 43
Figure 2.1 Photographic view of Pakistani waste rice husk and an activated rice husk ash 61
Figure 2.2 Schematic diagrams showing new method of waste automotive oil regeneration. 63
Figure 2.3 Transesterification reaction 65
Figure 2.4 Flow Chart of biodiesel production process. 66
Figure 2.5 Schematic diagram of a batch reactor used for cracking of waste engine oil. 68
Figure 2.6 Waste tyre oil pyrolysis process flow sheet. 69
Figure 2.7 Schematic diagram of experimental setup. 70
Figure 2.8 Photographic view of the diesel engine 72
Figure 2.9 Photographic view of the exhaust gas analyzer. 73
Figure 2.10 Photographic view of the smoke meter. 74
Figure 2.11 Photographic view of the blends agitator. 75
Figure 2.12 Photographic view of diesel, waste canola oil biodiesel, waste soybean oil biodiesel, waste transformer
oil methyl ester, waste engine oil and waste tyre pyrolysis oil from left to right (1-6) correspondingly. 78
Figure 2.13 Photographic view of viscosity baths 79
Figure 2.14 Photographic view of Hydrometer. 80
Figure 2.15 Photographic view of bomb calorimeter 82
Figure 2.16 Photographic view of flash point apparatus. 83
Figure 2.17 Photographic view of potentiometer for total acid number. 84
Figure 2.18 Photographic views of pour point apparatus. 85
Figure 2.19 Photographic view of high temperature furnace for ash contents test. 86
Figure 2.20 Photographic view of distillation unit. 88
Figure 2.21 Photographic view of FT-IR Spectrometer and data acquisition system. 91
Figure 3.1 Comparison of Kinematic Viscosity at 100 & 40 oC, Viscosity Index and Flash 96
Figure 3.2 Comparison of specific gravity, total acid number mgKOH/g and water contents Vol.% of the engine oil
re-refined with different techniques. 97
Figure 3.3 Graphical presentation of calorific value, cetane index and sulfur contents of different waste oil biodiesel
and petroleum diesel. 101
Figure 3.4 Graphical presentation of distillation of different waste oil biodiesel and petroleum diesel samples. 101
xvi
Figure 3.5 FT-IR Spectrum of waste sunflower oil (WSFO). 104
Figure 3.6 FT-IR of biodiesel (methyl esters) derived from waste sun flower oil (ME-WSFO). 105
Figure 3.7 FT-IR Spectrum of waste corn oil (WCRO). 106
Figure 3.8 FT-IR Spectrum of Methyl esters (biodiesel) prepared from waste corn oil (ME-WCRO). 107
Figure 3.9 FT-IR Spectrum of waste soybean oil (WSBO). 108
Figure 3.10 FT-IR Spectrum of Methyl esters (biodiesel) prepared from waste soybean oil (ME-WSBO). 109
Figure 3.11 FT-IR Spectrum of waste canola oil (WCAO). 110
Figure 3.12 FT-IR Spectrum of Methyl esters (biodiesel) prepared from waste canola oil (ME-WCAO). 111
Figure 3.13 FTIR spectrum of diesel 113
Figure 3.14 FTIR spectrum CFB fuel 113
Figure 3.15 Comparison of density of various composite fuel blends derived from a mixture of waste engine oil and
waste canola oil biodiesel to the ASTM and European Standards. 115
Figure 3.16 Comparison of kinematic viscosity of various composite fuel blends derived from a mixture of waste
engine oil and waste canola oil biodiesel to the ASTM and European Standards. 115
Figure 3.17 Comparison of flash point of various composite fuel blends derived from a mixture of waste engine oil
and waste canola oil biodiesel to the ASTM and European Standards. 116
Figure 3.18 Comparison of acid value of various composite fuel blends derived from a mixture of waste engine oil
and waste canola oil biodiesel to the ASTM and European Standards. 116
Figure 3.19 Comparison of calorific value of various composite fuel blends derived from a mixture of waste engine
oil and waste canola oil biodiesel to the ASTM and European Standards. 117
Figure 3.20 Comparison of water contents of various composite fuel blends derived from a mixture of waste engine
oil and waste canola oil biodiesel to the ASTM and European Standards. 117
Figure 3.21 Variations of Ignition Delay vs Engine Load Percent. 118
Figure 3.22 Variations of Heat Release Rate vs Cranke Angle Degree 120
Figure 3.23 Variations of Cylinder Pressure vs Engine Load Percent. 121
Figure 3.24 Variations of fuel consumption vs Engine Load Percent. 122
Figure 3.25 Variations of brake thermal efficiency vs engine load percent. 123
Figure 3.26 Variations of exhaust gas temperature vs engine load percent. 123
Figure 3.27 Variation of hydrocarbon emissions vs engine load percent. 125
Figure 3.28 Variations of Carbon monoxide emissions vs engine load percent. 126
Figure 3.29 Variation of oxides of nitrogen emissions vs engine load percent. 127
Figure 3.30 Variation of smoke opacity vs engine load percent. 128
Figure 3.31 FTIR spectrum of diesel. 129
Figure 3.32 FTIR spectrum of BLF 129
Figure 3.33 Comparison of density of various biodiesel like fuel (BLF) blends derived from a mixture of waste
transformer oil and waste canola oil biodiesel to the ASTM and European Standards. 131
Figure 3.34 Comparison of kinematic viscosity of various biodiesel like fuel (BLF) blends derived from a mixture of
waste transformer and waste canola oil biodiesel to the ASTM and European Standards. 131
Figure 3.35 Comparison of flash point of various biodiesel like fuel (BLF) blends derived from a mixture of
waste transformer and waste canola oil biodiesel to the ASTM and European Standards. 132
xvii
Figure 3.36 Comparison of acid value of various biodiesel like fuel (BLF) blends derived from a mixture of
waste transformer and waste canola oil biodiesel to the ASTM and European Standards 132
Figure 3.37 Comparison of calorific value of various biodiesel like fuel (BLF) blends derived from a mixture
of waste transformer and waste canola oil biodiesel to the ASTM and European Standards. 133
Figure 3.38 Comparison of water contents of various biodiesel like fuel (BLF) blends derived from a mixture
of waste transformer and waste canola oil biodiesel to the ASTM and European Standards. 133
Figure 3.39 Variation of ignition delay vs engine load percent. 134
Figure 3.40 Variations of heat release rate vs crank angle, degree at maximum engine load 135
Figure 3.41 Variation of cylinder pressure vs engine load percent. 136
Figure 3.42 Variations of BSFC vs engine load percent 137
Figure 3.43 Variations of BTE vs load percent 138
Figure 3.44 Variations of EGT vs load percent 139
Figure 3.45 Variations of HC vs load percent 140
Figure 3.46 Variations of CO vs load percent 141
Figure 3.47 Variations of NOx vs load percent 142
Figure 3.48 Variation of smoke opacity with engine load % for engine fueled with 143
Figure 3.49 FTIR spectrum of diesel 145
Figure 3.50 FTIR spectrum of FMWO 145
Figure 3.51 Comparison of density of various fuel blends derived from a mixture of waste tyre pyrolysis oil
and waste cooking oil biodiesel to the ASTM and European Standards. 146
Figure 3.52 Comparison of kinematic viscosity of various fuel blends derived from a mixture of waste tyre pyrolysis
oil and waste cooking oil biodiesel to the ASTM and European Standards. 147
Figure 3.53 Comparison of flash point of various fuel blends derived from a mixture of waste tyre pyrolysis oil
and waste cooking oil biodiesel to the ASTM and European Standards. 147
Figure 3.54 Comparison of acid value of various fuel blends derived from a mixture of waste tyre pyrolysis oil
and waste cooking oil biodiesel to the ASTM and European Standards. 148
Figure 3.55 Comparison of calorific value of various fuel blends derived from a mixture of waste tyre
pyrolysis oil and waste cooking oil biodiesel to the ASTM and European Standards 148
Figure 3.56 Comparison of water contents of various fuel blends derived from a mixture of waste tyre
pyrolysis oil and waste cooking oil biodiesel to the ASTM and European Standards. 149
Figure 3.57 Variation of ignition delay with engine load % for engine fueled with 150
Figure 3.58 Variation heat release rate with engine load % for engine fueled with Different FMWO fuel blends. 151
Figure 3.59 Variation of maximum cylinder pressure with engine load % for engine fueled with Different
FMWO fuel blends. 152
Figure 3.60 Variations of BSFC vs engine load%. 153
Figure 3.61 Variations of BTE with engine load%. 154
Figure 3.62 Variations of EGT with engine load%. 155
Figure 3.63 Variation of HC emissions with engine load % 156
Figure 3.64 Variation of CO emissions with engine load %. 157
Figure 3.65 Variation of NOx emissions with engine load %. 158
xviii
Figure 3.66 Variation of smoke opacity with engine load %. 158
Figure 3.67 FTIR spectrum of diesel. 161
Figure 3.68 FTIR Spectrum of WCOB. 161
Figure 3.69 Comparison of density of various fuel blends derived from a mixture of waste cooking oil
biodiesel and diesel to the ASTM and European Standards. 162
Figure 3.70 Comparison of kinematic viscosity of various fuel blends derived from a mixture of waste cooking
oil biodiesel and diesel to the ASTM and European Standards. 163
Figure 3.71 Comparison of flash point of various fuel blends derived from a mixture of waste cooking oil biodiesel
and diesel to the ASTM and European Standards. 163
Figure 3.72 Comparison of acid value of various fuel blends derived from a mixture of waste cooking oil
biodiesel and diesel to the ASTM and European Standards. 164
Figure 3.73 Comparison of calorific value of various fuel blends derived from a mixture of waste cooking
oil biodiesel and diesel to the ASTM and European Standards. 164
Figure 3.74 Comparison of water contents of various fuel blends derived from a mixture of waste cooking
oil biodiesel and diesel to the ASTM and European Standards. 165
Figure 3.75 Variation of the ignition delay with engine load % for an engine fueled with different waste
cooking oil derived biodiesel blends and petroleum diesel. 166
Figure 3.76 Variation of heat release rate with crank angle at maximum engine load% for engine fueled
with diesel and different waste cooking oil derived biodiesel blends. 167
Figure 3.77 Variation of maximum cylinder pressure with engine load % for engine fueled with Different
biodiesel blends derived from waste cooking oil. 168
Figure 3.78 Variation of brake specific fuel consumption with various loads for an engine 169
Figure 3.79 Variations of BTE with engine load 169
Figure 3.80 Variations of EGT with engine load% 170
Figure 3.81 Variation of HC emission with various load conditions for an engine fueled with diesel and different
waste cooking oil derived biodiesel blends. 172
Figure 3.82 Variation of CO emission with various load conditions for an engine fueled with diesel and different
waste cooking oil derived biodiesel blends. 173
Figure 3.83 Variation of NO emission with various load conditions for an engine fueled with diesel and different
waste cooking oil derived biodiesel blends. 173
Figure 3.84 Variation of smoke emission with various load conditions for an engine fueled with diesel and different
waste cooking oil derived biodiesel blends. 174
xix
Abbreviations
ASTM American society for testing and materials
BP Brake power
BSFC Brake specific fuel consumption
BTE Brake thermal efficiency
bTDC Before top dead center
CA Crank angle
CFB Composite fuel blends
CI Compression ignition
CO Carbon monoxide
DI Direct injection
EGT Exhaust gas temperature
FBP Final boiling point
FMWO Fuel mixture of waste oils (30% WTPO plus 70% WSOME)
FTIR Fourier transform infrared
GDP Gross domestic product
GHG Greenhouse gas
HC Hydrocarbon
HRR Heat release rate
IBP Initial boiling point
LHV Lower heating value
NA Naturally Aspirated
NDIR Non dispersive infrared
NO Nitrogen oxide
PC Personal computer
SD Smoke density
SI Spark ignition
TPO Tyre pyrolysis oil
TWTO Transesterified waste transformer oil
WCO Waste cooking oil
xx
WCOB Waste cooking oil biodiesel
WEO Waste engine oil
WPO Waste plastic oil
WSOME Waste soybeen oil methyl esters
WTO Waste transformer oil
WTPO Waste tyre pyrolysis oil
1
CHAPTER 1
GENERAL INTRODUCTION AND LITERATURE REVIEW
1.1 Introduction
Generally, automotive lubricating oil is used as a lubricant in motor car, bus, truck and other
automotive vehicle engines. After a certain time period of use in these engines the lubricating
base oil becomes waste and is disposed of. The disposal of these waste oils causes environmental
pollution. On the other hand, the increasing awareness of the depletion of fossil fuel resources
and the environmental benefits has made alternative diesel and biodiesel like fuels more
attractive in recent times. It can also be used directly in most diesel engines without requiring
extensive engine modifications. However, in comparison to petroleum-based diesel fuel, the cost
of biodiesel is the major hurdle to its commercialization. The high cost is primarily due to the
raw material mostly neat vegetable oils. Waste oil is one of the economic sources of alternative
fuel production for compression ignition diesel engines.
The waste or used oil is regarded as highly pollutant mass which needs proper attention to be
well managed. It is estimated that about 24 million tons of waste engine oil are produced every
year throughout the world. Waste oil may be responsible for the damage to the environment if
dumped into water streams and soil. Most countries use to dispose the waste oil in combustion
and incineration for the purpose of energy recovery. Such disposal routes are not proper
solutions for the environmental problems as the waste oil contains so many undesirable
contaminants (Audibert, 2006). The waste engine oil contains salt, water, decomposed
components of additives, gums, varnishes and other toxic materials which on exposure to the
surrounding environment, cause harmful effects to aquatic life as well as to human beings
(Durrani et al., 2011: Kamal et al., 2009). The fresh lubricating oil when subjected to
2
degradation and is contaminated with metals, ash, carbon residue, water, varnish, gums, and
other contaminating materials is also reffered as waste oil. Today, it has been a serious problem
for industries, environmentalists, research scientists and governments to handle the waste
lubricating oils. It is very much costly and hard task to dispose of these wastes in an
environmentally acceptable way. Burning the waste oils for generation of energy is a common
disposal technique, but unfortunately, this route of disposal is uneconomical and results in
wastage of resources. As reported by Bhaskar et al., (2004), in the past, the waste oil disposal
methods were land filling, indiscriminate dumping, road oiling, burning for energy generation
etc. All these methods have created serious environmental hazards (Bhaskar et al., 2004). In
advanced countries, like USA, UK, Ausralia, Germany, Japan and China, such types of waste
oils disposal techniques have been restricted and new environmental friendly regulations have
been issued. Therefore, the best solution of such dirty disposal techniques is the recycling of
waste oils to get energy and might serve as a part of an economical substitute to fossil fuel
energy. In our country Pakistan, especially in Southern Punjab region, the conventional methods
of recycling of waste oils either involve the use of toxic materials such as sulfuric acid or require
a high cost technology like vacuum distillation. Such methods also generate hazardous by-
products which are very harmful for the environment and human health. Francois et al., (2006)
reported that the primary function of lubricating oil was to reduce friction among the various
moving parts of the engines or machineries, to decrease the wear of engine parts, to minimize the
fuel consumption, to improve the working efficiency and to increase the life of the the engines or
machineries. Apart from lubrication properties of the lubricating oil, it keeps the equipment
clean, prevents corrosion and removes unwanted heat (Francois et al., 2006).
3
Many studies have concluded that the lubricants play a vital role for minmizing the operating
costs of industrial machinery as a result of the loss of energy and materials. The estimated world
wide consumption of engine lubricants has been reported to be 1.6 to 10.7 billion gallons per
annum (William Fan, 2010). However, recycling of only 2 billion gallons of waste lubricants
takes place in the world (Federico Garcia, 2009). Because of the worldwide shortage of
petroleum energy, recycling of the waste lubricants to generate energy is the need of the time.
Most conveniently, waste oil recycling for energy generation has a lot of benefits, such as
protection of environment, minimization of hazards and reducing wastes thereby conserving
natural resources.
Diesel fuel is derived from crude oil after its refining in the refineries. Due to increase of
population of the world at faster rates, it is assumed that the crude oil resources are expected to
be finished in the near future and the world would severely face the shortage of petroleum
products. Unfortunately, in Pakistan, there are no sufficient resources of crude oil. So, the
country completes its 85% needs of crude mineral oils importing from Middle-East countries and
spends more than 10% of its foreign exchange for crude oil imports and refined petroleum
products. Every year, for the purchase of crude oil, the country is facing a big import bill due to
the high costs of the oil. Therefore, to carry out such huge expenditure, the economic structure of
the country almost remains in scattered condition. So, all possible measures or attempts should
be adopted to find out the alternative ways for fuel production so that the people of this country,
even of the whole world can survive the situation. Production of diesel and biodiesel fuel from
waste oils is possible by using chemical treatment, filtration and blending process. Very few
studies have been carried out using waste oils regeneration (Federico, 2009; Cunha et al., 2009).
As reported by Cunha et al., (2009), biodiesel might be the alternative fuel for diesel engines.
4
According to him, animal fats, vegetable oils and renewable lipids can be raw materials for the
synthesis of biodiesel. EPA (environmental protection agency) has approved biodiesel as
additive for fossil fuel as well as a renewable fuel (Cunha et al., 2009).
1.1.1 Worldwide Energy Consumption
According to research studies reported by Sahir et al., (2007), the economic growth of any
country depends on the availability and its affordability of sustained energy supplies. Energy
demand is increasing globally due to population growth, improved living standards, access and
availability of energy resources to the poor especially in developing countries (Gertler, 2012).
Several future outlooks show that by 2040, the world population is likely to increase from 7
billion to around 9 billion, with 35% more energy demand than that of current level (Department
of Economic and Social Affairs, 2012). The world energy consumption has also been growing at
a rate of 5.4% per annum in residential buildings since 1992 (Bacon et al., 2010; Hussain, 2010).
The backbone of socioeconomic development is the sustainable energy. But unfortunately,
millions of years ago, the energy formed by nature in the form of fossil fuel has now been
declared as finite. Among the countries of the world, big reserves of fossil fuel have been
uneventually distributed. These reserves are concentrated in a small number of countries. The
low-income and middle-income countries having no or very few oil and gas reserves available
today.
5
Table 1.1 Energy consumption per capita 2007
Sr. No. Country Energy Consumption per capita
(2007) Kgoe
1 Pakistan 490
2 China 1320
3 India 490
4 Malaysia 2420
5 Thailand 1560
6 UK 3895
7 USA 7885
8 High income Countries 5520
9 Middle income countries 1510
10 Low income countries 490
Kgoe = Kilograms of oil equivalent
According to research reported by Department of Economic and Social Affairs (2012), energy
consumption for selected countries per year per capita is given in Table 1.1. Pakistan consumes
very little energy per capita. Today, in Pakistan we are facing major challenges in the field of
energy.
1.1.2 Energy Scenario in Pakistan
Energy is one of the prime and most important drivers which influence the future prospects of a
society (Gould, 2008). Without energy, it is impossible for the nations to run on the path of
progress. As reported by Amjid (2011), the country Pakistan is having many renewable resources
of energy, but very small portion is going to be utilized at present. Every year, for the imports of
fossil fuels, Pakistan spends around 7 billion US dollar to complete the energy demands of the
country.
6
Figure 1.1 Supply demand gap in Pakistan 2002-2030
As the fossil fuels are diminishing rapidly, we cannot rely only on them to fulfill the energy
needs of our country. Figure 1.1 shows supply and demand gap of energy (Siddiqui, 2011). By
the year 2050, it is estimated that the energy demands in Pakistan would increase upto three-fold
(Asif, 2009; Kalim, 2011). It is necessary that using renewable energy options, Government of
Pakistan and the private sectors must enhance the power generation in Pakistan. The energy
problem started in 2005 in our country Pakistan. Since that time, the gap between supply and
demand of electricity has increased and is projected to go up to 23,700 MW by 2030.
In Pakistan, the population growth is increasing at a faster rate. As result of increase in
population, the demand of energy also increases. Pakistan stands at number 6 among the most
populous countries in the world with a population more than 180 million in 2013. According to
future estimates of 2035, the population growth would go upto 350 million citizens in 2035
(Economic Survey of Pakistan, 2008-09). At present, Pakistan is facing the severe energy crisis
7
and energy shortage has declined the economic growth (Institute of Public Policy, 2010). This
energy crisis has also ruined the social welfare and created unrest in the form of unemployment
and mental anxiety. Based on the data of Economic Servey of Pakistan (2013-14), all major
sectors such as residential, industrial, commercial, agriculture, and transport have consumed
nearly 60 MTOE (millions tonnes of oil equivalent) of final energy. The electricity balance has
been severely disturbed due to 7000-9000 MW shortage in energy supplies in 2013 (Economic
Survey of Pakistan 2013-14).
1.2 Literature Review
Alternate energy search by using cheap, environment friendly and non-edible resources is a
burning issue throughout the world due to increasing awareness of rapid depletion of fossil fuel
resources and high cost of petroleum based fuels in recent times. Some of the relevant literature
is given below:
1.2.1 Renewable Energy
In Pakistan, there was no concept of using renewable energy untill the year 2003 (Khalil et al.,
2007). Thereafter, to synchronize, expedite and encourage the renewable or alternative energy
technologies an Alternative Energy Development Board (AEDB) came into force and it was
emphasized that by the year 2030, five percent increase of power generation is expected through
renewable energy resources. In the year 2012, the board formulated Alternative and Renewable
Energy (ARE) Policy that included all alternative energy technologies together with wind, hydro,
solar, geothermal, cogeneration, waste-to-energy and biogas offering very attractive monetary
and economic benefits to both native and overseas stackholders. In the rural areas of Pakistan,
the people encounter over and above 95% of their household energy requirements through
biofuels (Renewable Information, 2006; World Energy Council, 2006).
8
Table 1.2 Renewable energy potentials for Pakistan
Sr. No. Energy Type Estimate (MW)
1 Wind 340,000
2 Geothermal 550 3 Biogases Cogeneration 1800
4 Hydro (mini) 2000
5 Hydro (small) 3000
6 Hydro (large) 50,000
7 Waste-to-Energy 500
8 Solar 2.9
Renewable energy potentials for Pakistan is given in Table 1.2 as reported by (ESMAP, 2006).
But unfortunately, this huge energy potential of energy is still unused in Pakistan.
1.2.2 Search for Alternative Fuels
One of the most important issues that affects the world economy and politics is the sustainability
of energy. The conventional energy sources are mainly considered for heat and power
applications. However, due to the depletion of fossil fuels and increased awareness of
environmental problems, the world is looking to use alternative fuels in the form of renewable or
non-conventional fuels. Renewable energy sources are derived from natural sources like sun,
water, wind and biomass, while non-conventional fuels may be derived from some other
methods such as thermo chemical conversion, thermoelectric or thermionic conversions etc.
Energy can be derived from waste organic substances which are considered non-conventional
fuels.
Research works carried out on the diesel fuel properties, spray characteristics, mixture formation
and combustion processes which have become key factors (Hiroyasu et al., 1974; Arai et al.,
1985; Tabata et al., 1991). In later development, with the introduction of alternative fuels, the
diesel engines were investigated with different fuels; biodiesel and alcohols. Investigations were
carried out on gaseous fuels such as hydrogen, acetylene, liquefied petroleum gas (LPG),
compressed natural gas (CNG), biogas and producer gas with diesel fuel on dual fuel mode (Geo
9
et al., 2008; Saravanan et al., 2010; Lakshmanan et al., 2010; Sharma et al., 2012; Tira et al.,
2012; Chandra et al., 2011).
1.2.3 Engine Tribology
Lowering emission rates and improved fuel efficiency of compression ratio ignition engines has
always been a challenge for the automotive industry due to stringent government regulation. This
leads to the demand for higher energy-conserving engine oils to reduce friction and conserve
natural resources. There are many tribological contacts in engines that need effective lubrication
to avoid energy losses; these include piston assembly, bearings, transmissions, gears and drive
train components (Tung et al., 2004).
Literature reported that in the field of Chemistry, Physics, Applied Mathematics, Materials
Science, Thermodynamic, Rheology, Heat Transfer, Surface Engineering, Fluid Mechanics and
Solid Mechanics, the combination of Science and Technology is referred as engine tribology
(Bhushan, 2002). Due to poor lubrication on the interacting surfaces, more friction and wear was
found experimentally and a noticeable loss in energy or even an accidential damage was
observed at the time of relative motion (Khonsari et al., 2008). According to the Institute of
Engineering and Technology (2009), the green tribology protects environment, saves the energy
and engine material. Khonsari et al., (2008) reported that the green tribology for modern
industries has become very much necessary programs so as to take hundred percent benefits from
the energy efficiency and to reduce the losses in the materials and environmental impacts.
1.2.4 Metal Surfaces
The metal surfaces cannot be 100% smooth. There is a variety of irregularities and deviations of
geometrical structure of metal surfaces. As per studies of Whitehouse, (1994), Bhushan, (2002)
10
and Thomas, (1999), these deviations appear on the surface of metal and alloys due to the natural
formation process.
1.2.4.1 Layers of Metal Surface
There are different layers associated with the metal surface. According to the studies of (Gatos,
1968; Haltner, 1969; Buckely, 1981; Bhushan, 2002), the thickness of the layers varies
depending on the temperature applied, the production process and the degree of oxidation.
1.2.4.2 Physisorbed Layer
The metal surfaces can adsorb a variety of molecules like water vapor, oxygen and grease
contents to form a layer (monomolecular or polymolecular) due to physical interaction or in
other words due to weak van der Waals forces of attraction between metal surface and adsorbed
molecules (Haltner, 1969; Bhushan, 2002). In comparison to the chemical bonds of adsorbed
molecules, the van der Waals force is considered to be a very weak force. So the physisorbed
layer can be easily removed (Bhushan, 2002).
1.2.4.3 Chemisorbed Layer
Mostly, this layer is formed at an elevated temperature and it is covalently bonded
monomolecular layer having adsorbed smaller molecules of water, oxygen or grease molecules
on metal surface (Bhushan, 2002). The chemisorbed layer contains high bonding energy (10 to
100 kcal/mole) in comparison to physical bond energy (1 to 2 kcal/mole) in physisorbed layer
(Bhushan, 2002). So, the studies confirmed that the removal of physisorbed layer from its metal
surface is easier as compared to that of chemisorbed layer.
1.2.4.4 Oxide Layer
As a result of oxidative reactions between metal and other reactive molecules as well as friction
process, the formation of oxide layers usually occurs at metal surfaces (Bhushan, 2002). The
11
ingredients of oxide layer consist of mixed-oxides or monooxides. Kubaschewski et al., (1953)
declared that the iron oxides (like FeO and Fe2O3), mixed oxides of chromium and iron are the
typical examples of oxide layers. In a favorable environment, many oxide layers like chromium
oxide and ferrous oxides are able to grow continuously. On the other hand, some metal oxides
like titanium oxide might act as a layer on the metal surface as reported by Bhushan, (2002).
1.2.4.5 Beilby Layer
During the process of melting, lapping or polishing, the Beilby layer is produced due to
quenching of molecular layers of alloys and metals. It has either microcrystalline or amorphous
structure (Bhushan, 2002; Goswami, 1996).
1.2.4.6 Deformed Layer
A strained layer is known as deformed layer. This strained zone in alloys and metals is generally
created beacause of a temperature gradient at the time of grinding, lapping, machining, friction
and polishing process (Bhushan, 2002). The characteristics of original material completely differ
from the stretched part of material. The deformation degree is always dependent on the type and
nature of the work carried out (Samuels, 1960; Bhushan, 2002; Shaw, 1997).
1.2.5 Friction and Wear
Between two adjacent surfaces, the resistance force against the interface motion is known as
friction. In engines or machines, the existence of friction might reduce the energy efficiency and
may generate high amounts of heat thereby creating more wear on the engine parts. As a result of
this type of wear, the operating costs would be increased manifold.
In tribology, the following kinds of friction might occur;
i) Sliding friction which occurs as a result of interactions of two sliding surfaces, the
examples are adhesion, sloughing and deformation.
12
ii) Rolling friction which occurs because of sliding over of two rolling surfaces to
each other.
As discussed earlier the surfaces of metals are not smooth completely. In a relative motion, a
kind of damage due to high friction on two rough surfaces of metals is referred to a metallic
wear. Khonsari et al., (2008) stated that the wear might increase the noise, surface stresses,
vibrations and metallic parts damage. The cause and types of wear are summarized in Table 1.3
(Eyre, 1976; Engel, 1976; Suh and Saka, 1980; Peterson and Winer, 1980; Scott, 1979; Suh,
1986; Zum Gahe, 1987; Loomis, 1985; Batchelor, 2000; Bhushan, 2002; Hutchings, 1992;
Buckley, 1981).
Table 1.3 Commonly Found wear types at the Surface of Metals and Alloys
Sr.
No. Type of Wear Causing Agent
1 Erosive Wear Repetitive impingement of solid particles
2 Corrosive Wear Oxidative reaction with corroding agents e.g. water
3 Electrical Induced Wear High electrical potential or plasma
4 Abrasive Wear Repetitive scraping of hard particles
5 Fretting Wear Low-amplitude oscillatory motion
6 Percussion Wear Repetitive high speed solid impact
7 Fatigue Wear Repetitive stresses under sliding and rolling
8 Adhesive Wear Adhesion between contacting surfaces
1.2.6 Science of Lubricating Oil
For all modern industries, lubricant plays a vital role in controlling wear and friction. The
importance of the lubricating oil in respect of composition, lubricant properties, lubricant
additives (such as antioxidants, antiwears, viscosity index improvers, detergents, flash point
depressants, antifoaming additives, pour point improvers, anticorrosion additives) are discussed
in the next upcoming sections.
13
1.2.6.1 Composition of Lubricating Oil
To protect the machines from the wear, the modern industries need high performance lubricants.
Generally, for the sake of better performance inside the engine, modern lubricants contain base
materials as well as a various additives. Commonly, the lubricants used today consist of 80 to
95% of base oils and 5 to 20% of different additives (Singh, 2002).
1.2.6.2 Lubricant Base Oils
The lubricant base oils can be produced by using the following materials:
i) Petroleum (crude oil) derived mineral oils;
ii) Long-chain artificial molecules, like organic esters, polyglycols, synthesized
hydrocarbon fluids, phosphate esters, silicate esters and silicones.
iii) Animal fat and plants derived oils (Singh, 2002).
For the sake of animal protection and some undesirable properties, the use of animal fat for the
lubricant base stocks is no longer practical as reported by Schneider, (2006).
1.2.6.3 Lubricant Additives
To enhance the performance, certain essential additives are mixed in the modern lubricants in all
over the world. Since 1920s, for the performance enhancing purpose, a variety of additives were
used in lubricants. The worldwide consumption of lubricant additives was reported to be 5.7
billion pounds around the world during 1997. However, it is expected that the need of additives
would increase by many fold untill the year 2025 due to fast economic growth in Latin America
and Asia (ASTM, 2009). Mostly, additives are the combined form of chemical compounds
(Lepera, 2000). For the enhancement of lubricant performance, the following typical additives
are being used today.
14
1.2.6.3.1 Antioxidants
The antioxidants are also called oxidation inhibitors. The viscosity of the lubricants increases
when they are oxidized, this leads to the the formation of the corrosive products just like organic
acids (Audibert, 2006). Normally, the rate of oxidation processes is temperature dependant. The
rate of oxidation is slow, when the temperature is below 200˚F (93˚C), however, the oxidation
process is initiated by the chain reaction of free radicals like peroxy radicals (HO`2), this is
possible as a result of the oxidation of unstable hydrocarbon molecules. According to the studies
of Mortier et al., (1997), aromatic amines (like N-phenyl-α-naphthylamine) and alkylated
phenols (like 2,6-ditertiary-butyl-4-methylphenol) are generally used as additives for lubricants
so as to hinder the chain reaction by neutralizing the free radicals.
1.2.6.3.2 Antiwear Additives
A protective film is formed by the antiwear additives over the metal part surfaces. As per studies
of Audibert, (2006) and Mortier et al., (1997), antiwear additives protect the engine machinery
being worn out, the examples of such additives are polar hydrocarbon derivatives such as fatty
amines, alcohols and fatty esters (Mortier et al., 1997).
1.2.6.3.3 Viscosity Index (VI) Stabilizers
Change in viscosity with temperature is referred to as viscosity index. In general, viscosity of
oils is inversely related to the temperature. The lubricant might lose its characterististics and
function thereby creating negative effects to the engines or machines, if the lubricant’s viscosity
is too high. To maintain the stability of lubricant’s viscosity, viscosity index stablizers are
commonly used. Therefore, at an elevated temperature, the viscosity index stabilizers having
long-chain polymers have a powerful capability to keep intact the viscosity of lubricants.
Examples of such polymers are methacrylate polymers (Audibert, 2006).
15
1.2.6.3.4 Detergents and Dispersing Agents
In order to control the formation of lacquer or varnish, the dispersing agents are mixed well with
lubricating oils. There is the danger of deposition of such varnishes on the surface parts and
combustion chamber of the vehicle engines. In this way, the efficiency of the engine might be
reduced, even parts might be damaged due to more friction as reported by Audibert, (2006). To
keep engines clean and ready to operate properly, the alkaline earth metal salts like magnesium
and calcium sulfonates and phenates are commonly used. Lacquer and varnish adsorption is
highly destabilized by polymeric succinimides like alkenylsuccinimides and benzylamides (Pirro
et al., 2001; Audibert, 2006).
1.2.6.3.5 Antifoaming Additives
Detergents and dispersing additives may cause the formation of air bubbles, so called foaming, in
lubricants depending on the characteristics of lubricants. Foaming might reduce the efficiency of
lubricants and engine. Alkyl polymethacrylate and silicon polymers having lower weight
(molecular) are mostly used as antifoaming additives. These additives reduce the surface tension
and collapse the air bubbles produced in the lubricants (Audibert, 2006; Mortier et al., 1997).
1.2.6.3.6 Pour Point Improving Additives
The temperature (lowest) at which the flow of the lubricant ceases to exist is referred as pour
point. During the cold weather, smooth working of the vehicle engines is required. But it is not
possible without the use of pour point improver in the lubricants. Actually, the mobility of
lubricant at a low temperature is reduced with the formation of paraffin wax crystals. Mostly,
alkylaromatic polymers and polymethacrylate are used as pour point improving additives to
hinder the formation of paraffin wax crystals in the lubricants (Audibert, 2006).
16
1.2.6.3.7 Anticorrosion Additives
Research has confirmed that the engine parts are comprised of lead-bronze or copper-lead metals
and alloys. These metals and metal alloys might be easily corroded by acids. According to
Mortier et al (1997) and Audibert (2006), the strong acids are produced during combustion inside
the engine due to the presence of sulfur compounds and antiknock materials in the fuel. The most
common anticorrosion additives to protect metal surfaces are amine succinates alkaline earth
sulfonates (Pirro et al., 2001).
1.2.7 Waste Lubricants
Many researchers have confirmed that waste engine oils are hazardous substances and their
degradation is very slow. In this regard, raising public awareness to handle waste lubricants
properly with care is the need of the time. As per studies of Audibert (2006), the regeneration of
waste engine oil is very important so as to get benefits of reduced hazards, conserved energy and
environmental protection.
1.2.7.1 Composition of Waste Lubricants
Depending upon the source of collection, the composition of waste lubricants is different at
different places. The composition of waste lubricants deviates from their parent virgin base oils
(C4 to C50) as the waste oils contain pollutants such as soot aggregates, metal fragments, dirts,
soot gel networks and some organic compounds such as xylene, benzene and toluene.
Determination of the exact composition of waste lubricant is not easy as its composition varies
depending upon the age and type of the machineries in which it has been used.
1.2.7.2 Compounds of Carbon and Hydrogen
According to CEPA (1994), 50% of the lubricants are being burnt off in the combustion engine
due to incomplete combustion of fuels like gasoline and diesel. The major components in the
17
lubricants are carbon and hydrogen in the form of long chains. Guibet (1999), declared through
his research work that in waste lubricants majority of hydrocarbons are present due to the
remaining unburnt fuels and lubricants. Unburnt fuels are mostly diesel and petrol. Diesel fuel is
different from gasoline in many aspects. Common physico-chemical properties of diesel and
petrol are given in Table 1.4 as reported by Guibet (1999).
Table 1.4 General Characteristics of Diesel and Gasoline
Sr.
no. Description Diesel Gasoline
1 Specific Gravity at 60oF 0.82-0.86 0.72-0.77
2 Aromatics (Vol.%) 10.0-30.0 15.0-45.0
3 Olefins (Vol.%) 0 0-20
4 Naphthenes (Vol.%) 20-30 0-5
5 Paraffins (Vol.%) 50-65 40-45
6 Hydrogen/Carbon (atomic ratio) 1.9-2.1 1.7-1.9
1.2.7.3 Additives for Lubricants and Fuels
According to Erdal, (2004) and Guibet, (1999), the additives present in waste lubricants
generally, come from unburned fuels or lubricants. The common additives used in petrol
(gasoline) are given in Table 1.5. Maximum care might be taken to store diesel fuel in storage
tanks because if the tank is contaminated with moist air, then many kinds of microorganisms
such as fungi, bacteria, and yeasts would be able to grow in diesel storage tanks and contaminate
the diesel fuel (Guibet, 1999).
18
Table 1.5 Additives Used for Gasoline Fuel
Sr. No. Additives Aggregate Compounds
1 Antioxidants Alkyl-p-aminophenols
Alkylphenols
Alkyl-p-phenylenediamines
2 Octane rating improver Tricarbonyl (MMT)
Methyl cyclopentadienyl manganese
Ethylene dibromide
N-methylaniline
Iron pentacarbonyl
Aniline
Iodine
Nickel carbonyl
Tetraethyl tin
Lead alkyls
Dicyclopentadienyliron
3 Metal deactivators N,N'-disalicylidene-1,2-propanediamine
4 Detergents Polyisobutenylsuccinic anhydride derivatives
Polypropylphenol derivatives
Propylenediamine amides
To kill such type of bacteria and to stop the growth of microbes, different additives are used in
diesel fuels (Erdal, 2004). Diesel fuel additives are given in Table 1.6, hereunder (Erdal, 2004).
Table 1.6 Additives Used for Diesel Fuel
Sr. No. Additives Aggregate Compounds
1 Antioxidants N,N-dimethylcyclo-hexylamine
2 Biocides Quinoline
Cyclic amines
N-alkylpropanediamine
Imidazolines
3 Anti-forming Polysiloxanes
4 Demulsifiers Alrylsulfonates
Alkyloxypolyglycol
5 Cetane improvers Triethyleneglycol dinitrates
2-ethylhexyl nitrate
19
1.2.7.4 Polycyclic Aromatic Hydrocarbons (PAHs)
Because of the cyclization of low molecular weight unburned aromatic compounds in gasoline
engines formation of PAHs (polycyclic aromatic hydrocarbons) was experimentally observed
(Pruell et al., 1998; Audibert, 2006). PAHs are unlikely to form diesel engines as diesel is rich in
paraffins. In waste engine oils, the concentration of PAHs varies from 0 to 4210 μg/g depending
on the service life of lubricant, type of vehicle, age of vehicle and driving conditions (Wong et
al., 2001; Pruell et al., 1998).
Table 1.7 Polyaromatic hydrocarbons in waste lubricating oils
Sr. No. PAH No. of Aromatic
Rings
1 Anthracene 3
2 Fluorene 3
3 Phenanthrene 3
4 Acenaphthylene 3
5 Naphthalene 2
6 Acenaphthene 3
7 Fluoranthene 4
8 Benzo (a) anthracene 4
9 Pyrene 4
10 Chrysene 4
11 Benzo(f)fluoranthene 5
12 Benzo(b)fluoranthene 5
13 Dibenzo(a,h)anthracene 5
14 Benzo(a)pyrene 5
15 Benzo(g,h,i)perylene 6
16 Indeno(1,2,3-cd)pyrene 6
It was observed experimentally that in the used lubricants, the higher concentrations of PAHs
were found with longer use of the oil in the vehicle engines and machineries (Pruell et al., 1998;
Donahues et al., 1977; Hellou et al., 1997). The toxicity of PAHs to living organisms has been
confirmed by many studies (Bott et al., 1978). According to Wong et al., (2001), the toxicity of
PAHs is dependant to their structure. If the structure of PAHs contains four or more rings then
20
they are said to have carcinogenic effects to humans. The most typical PAHs present in waste
lubricating oils are given in Table 1.7 (Hedtke et al., 1980; Wong et al., 2001).
1.2.7.5 Water Contents
Moisture and water contents may be introduced into waste lubricants by the leakage of the
cooling system of vehicles, by blowby vapors in the air and the combustion of fuels (CEPA,
1994; Awaja et al., 2006; Yang, 2001). According to the research studies of Audibert, 2006, the
moisture content in waste lubricants was found to be 5-30%.
1.2.7.6 Trace Metals and Metallic Fragments
According to the research work and experimental observations of Awaja et al., (2006), the major
sources of trace metals present in waste lubricants are usually metallic fragments coming from
the wear of moving parts of the engines or machines.
1.2.7.7 Sand and Dirt
In the waste lubricants, sand or dirt is coming from collecting sites. It is very necessary to
remove dirt and sand before processing for recycling as reported by (Awaja et al., 2006).
1.2.8 Toxic Effects of Waste Lubricating Oil
As already discussed in previous sections, the waste lubricants belong to the hazardous family,
the U.S. EPA, has also confirmed the toxic effects of waste lubricants. Waste oils when dumped
through improper routes like water sheds, this type of improper disposal creates ground and
drinking water pollution posing a serious threat to the environment and human health.
1.2.8.1 Toxic Effects on Human Health
It has been proved from experiments that the waste oils contain (PAHs) polycyclic aromatic
hydrocarbons (PAHs). The main symbol of carcinogenic PAH is its strucrure, if the structure
contains four or more rings then it is said to be carcinogenic as reported by Wong et al., (2001)
21
and Harvey, (1985). Apart from carcinogenic effects to the humans, some other harmful effects
reported in the literature are reduced growth, birth defects such as brain or eye defects and an
increased rate of mortalities (CEPA, 1994; Albers, 1980).
1.2.8.2 Toxic Effects on Animals
The toxic effects of waste oils have been reported in animals, most prominently in newborn
animals. According to the studies of CEPA, (1994) and Hoffman, (1990), the eggshell surfaces
of mallard ducks and bobwhite quail were highly affected by the toxicity of waste lubricants. In
mallard duck embryos, 84% mortality was reported even with minute concentrations (0.003 ml)
of toxic waste oils exposure. In bobwhite quail embryos, 88% mortality was reported with
0.015ml exposure of toxic waste oils. Dumping of waste oils into waters is very harmful to
aquatic organisms (Byrne et al., 1977; MacLean et al., 1989; U.S. EPA, 1994).
1.2.9 Adsorption
1.2.9.1 Introduction
For quite a long time, the knowledge of adsorption phenomena to the mankind was due to the
purpose of purification and desired bulk separation processes. Usually, the porous solid medium
is the heart of an adsorption process.
Table 1.8 Important Definitions related to adsorption
Sr.
No. Term Definition
1 Adsorption Enrichment of one or more components in an interfacial layer
2 Adsorbent Solid material on which adsorption occurs
3 Adsorptive Adsorbable substance in the fluid phase
4 Adsorbate Substance in the adsorbed state
5 Physisorption Adsorption without chemical bonding
6 Chemisorption Adsorption involving chemical bonding
7 Surface coverage Ratio of amount of adsorbed substance to monolayer capacity
8 Monolayer capacity either Chemisorbed amount required to occupy all surface sites
or Physisorbed amount required to cover surface
22
The porous solid medium provides a very high micropore volume or high surface area. For the
sake of simplicity, some of the principal properties and terms associated with adsorption are
given in Table1.8 as reported by Rouquerol (1999).
1.2.9.2 Physisorption and Chemisorption
Two kinds of forces are involved, namely, physisorption and chemisorption, when adsorption is
about the interactions between the molecules in the fluid phase and the solid. Physisorption
forces are the same as those responsible for the deviations from ideal gas behavior and the
condensation of vapors. However, chemisorption interactions are particularly responsible for the
chemical compounds formation. The photographic view of a hypothetical porous grain having
different kinds of pores is given in Figure 1.2 as reported by Rouquerol (1990).
Figure 1.2 Photographic view of cross section of a hypothetical porous grain showing various types of pores:
closed (C), blind (B), through (T), interconnected (I), together with some roughness (R).
The features distinguishing between Physisorption and Chemisorption have been summarized as
follows:
(1) Chemisorption is dependent on the reactivity of the adsorbent and adsorbate, however,
Physisorption is a general phenomenon with a relatively low degree of specificity.
23
(2) Chemisorbed molecules are linked to reactive parts of the surface and the adsorption is
necessarily confined to a monolayer. Physisorption generally occurs as a multilayer at
relatively high pressures.
(3) If a physisorbed molecule undergoes reaction or dissociation and on desorption it returns
to the fluid phase in its original form. However, if a chemisorbed molecule is dissociated
then it does not retain its identity after being desorbed.
(4) Physisorption is always exothermic process. The energy of chemisorption is the same
order of magnitude as the energy change in a comparable chemical reaction.
(5) At low temperature the system may not have sufficient thermal energy to attain
thermodynamic equilibrium. Energy of activation is often involved in chemisorption.
1.2.9.3 Adsorbents
Koper (1997) observed that the porous solid is a critical variable for a given adsorption process.
A solid having good adsorptive capacity or good kinetics is referred to as a good solid. A high
quality solid must have following two aspects:
(1) It should contain surface area or micropore volume;
(2) For the transport of molecules to the interior, the solid should contain large pore network.
That is to say that the small pore size with a reasonable porosity is recommended for good
quality porous solids (Koper, 1997).
1.2.9 Alternative Fuels
1.2.9.1 Vegetable Oils
Detailed investigations on utilization of vegetable oils of edible and non-edible oil as alternative
fuels in compression ignition engines were investigated by several researchers (Labeckas et al.,
2006; Agarwal et al., 2008; Hanbey and Huseyin, 2010; Devana & Mahalakshmi, 2009; Nwafor,
24
2004; Acharya et al., 2009; Hossian, 2010; Hiroyasu and Kadota, 1974; Chandra et al., 2011;
Deshmukh et al., 2008; Yoona et al., 2001; Lakshmanan and Nagarajan, 2009; Sharma et al.,
2012; Lakshmanan and Nagarajan, 2010; Tira et al., 2012; Lakshmanan and Nagarajan, 2011).
It was reported that the raw plant oils showed a drop in power output, while some of them
showed a marginal increase compared to diesel fuel. In comparison with diesel fuel, the BSFC
with vegetable oils were found to be higher by about 2% to 15%. The oxides of nitrogen (NOx)
emissions were found to be lower while the carbon dioxide emission (CO2) was found
unchanged or increased in plant oils. The use of raw vegetable oils in diesel engines was found to
be successful for short term use (Hossian, 2010; Singh and Singh Dipti, 2010; Demirbas, 2009;
Arai et al., 1985; Demirbas, 2007; Tabata et al., 1991; Geo et al., 2008; Saravanan and
Nagarajan, 2009; Geo et al., 2009; Saravanan and Nagarajan, 2010).
1.2.9.2 Esters of Vegetable Oils
Transesterification is found to be a technically feasible for utilising the vegetable oil as a
compression ignition engine fuel to a greater extent. Numerous documents are available on
utilisation of biodiesel from edible and non-edible vegetable oils that were investigated by many
researchers (Ismet et al., 2010; Ramadhas et al., 2005; Baiju et al., 2009; Cheung et al., 2009;
Yu et al., 2008; Agarwala et al., 2008; Deepak et al., 2008; Raheman and Ghadge, 2007; Math,
2007; Nabi et al., 2009; Karabektas et al., 2008; Banapurmatha et al., 2008; Devan and
Mahalakshmi, 2009; Devan and Mahalakshmi, 2009; Sahoo et al., 2007; Sahoo and Das, 2009;
Srivastava and Verma, 2008; Jindal et al., 2010; Saravanan et al., 2010; Deshmukh and Bhuyar,
2009).
Due to inherent lubricity in comparison with diesel and lower soot formation the use of biodiesel
favours to improve the durability of engines. It was reported that the particulate emissions of
25
biodiesel were found to be reduced significantly in comparison to petroleum diesel because of a
lower aromatic content, higher cetane number, lower amount of sulphur compounds and higher
oxygen contents in biodiesel. Various research studies were performed to study the effect of
biodiesel on the NOx emissions including blended fuels (Sahoo et al., 2007; Singh and Singh
Dipti, 2010; Raheman and Ghadge, 2007; Dedobert, 1995; Ganesan, 2003).
1.2.9.3 Alcohols
Alcohols are renewable, easily producible and oxygenated resources in nature. Although
alcohols have lower cetane numbers, their merits mentioned above dominate. On the basis of
these merits numerous scientists and researchers have studied the use of alcohols such as ethanol,
methanol, and butanol in diesel engines. They have investigated the use of alcohol with diesel
and different biodiesels in the form of solutions, dual fuel mode, emulsions, surface ignition etc.
(Edgar et al., 2007; Wang et al., 2008; Kowalewicz and Pajaczek, 2003).
1.2.9.4 Pyrolysis Oils
It is a method of thermal degradation of the organic substances into value added products such as
pyro gas, pyrolysis oil, and carbon black or char. In other words pyrolysis is a method of
deriving alternative fuels from various feedstocks available in the form of liquids or solids. Many
studies have shown the use of pyrolysis oil in CI engines. Different feedstocks such as tyre,
wood, plastic and mixture of vegetable oil etc. were tried to obtain pyrolysis oil.
Some of the common problems reported by several researchers (Zhang et al., 2007; David et al.,
2003; Shihadeh and Hochgreb, 2000; Czernik and Bridgwater, 2004; Evans and Milne, 1987)
with the use of the pyrolysis oil or bio oil in CI engines are: (i) difficulty in starting the engine
due to the poor ignition quality of pyrolysis oil (ii) engine parts are affected due to corrosion and
erosion (iii) HC, CO and smoke emissions were found to be higher due to the complex
26
hydrocarbon chain or higher aromatic content present in the pyrolysis oil, and (iv) inferior
combustion compared to diesel or coking operation (Murugan et al., 2008).
1.2.9.5 Waste Oils
1.2.9.5.1 Waste Engine Oil
Literature review reveals that oils such as waste lubricating oil (WLO), waste plastic oil (WPO)
have also been investigated for their use as alternative fuels in CI engines. Arpa et al., (2010)
have examined WLO as an alternative fuel in a 10kW diesel engine a marginal increase was
found in BTE (brake thermal efficiency) and exhaust gas temperature at maximum load. The
brake specific fuel consumption was found to be marginally lower as compared to that of diesel
fuel. In terms of emissions, the carbon monoxide, nitrogen oxides and sulphur dioxide were
found to increase by 14.7, 12.7 and 22.5% respectively whereas oxygen was found to decrease
by 11.4%. Tajima et al., (2001) carried out an experimental investigation on a diesel generator
plant fuelled with used lubricating oil (ULO) as an alternative fuel. The results were compared
with heavy fuel oil. As compared to heavy fuel oil, the ULO showed better ignition quality,
however, lower smoke emission was found in comparison to heavy fuel oil operation.
1.2.9.5.2 Waste Plastic Oil
In another study, small powered diesel engine with waste plastic oil (WPO) as an alternative
fuel was investigated (Mani et al., 2009). The influence of four different injection timings (14,
17, 20 and 23 obTDC) on the combustion, performance and emission characteristics of a single
cylinder, four stroke, direct injection diesel engine was studied using WPO as a fuel. In
comparison with standard injection timing of 23obTDC (before top dead center) the retarded
injection timing of 14 obTDC, the WPO fueled engine showed a reduction in HC, CO and NOx
emissions by about 30%, 25% and4.4% respectively at maximum load. In comparison to diesel,
27
4% higher brake thermal efficiency and 35% higher smoke emissions were obsereved for WPO
at maximum load conditions. It was also noticed that the smoke emission was found to be higher
by 35% for WPO than that of diesel at full load.
Mani et al., (2009) have analysed the properties of WPO and declared that after refining, the
WPO might be used as an alternative fuel in diesel engines.
1.2.9.5.3 Waste Transformer Oil
Commonly, transformer oil is used in electrical transformers for insulation purpose. Some
changes occur in the physicochemical properties of the oil after a long-term usage, the oil is then
considered as waste oil which needs to be replaced. The transformer oil has been reported to
contain polychlorinated biphenyls (PCBs) which are cancer-causing. Therefore, improper
disposal of the oil and poor handling might cause serious environmental pollution (Gustavsson
and Hogstedt, 1997). As per the literature review, the studies on the patients exposed to PCBs
indicated the potential impact on gastrointestinal tract, liver and urinary tract cancers (Kalantar
and Levin, 2008). Elevated levels of some metals are very harmful to human health. The metals
like silver, iron, copper, lead, aluminum and zinc, have been reported to be present in waste
transformer oils. Copper can be found in transformer windings, iron can be found in the
transformer tank and core, aluminum is present in ceramic insulators and coils, silver, and zinc
are found in some peripheral components and lead is present in soldered connectors and joints of
the electric transformers (Hara, 1985). Disposal of waste transformer oil into land or water
causes environmental problems. The previous studies indicated that WTO could be used as a
diesel substitute so as to avoid the disposal related issues (Pullagura et al., 2012).
28
1.2.9.5.4 Waste Tyre Pyrolysis Oil
United Nations Environmental Protection Agency (2014) has reported that every year about 1.5
billion tyres are being produced world wide which would consequently become waste tyres.
Environmentalists and scientists are struggling continuously to get healthy and clean
environmental management of the wastes (Islam et al., 2008). After setting the tyres on fire, it is
very difficult to extinguish the fire resulting in sufficient release of air pollutant emissions which
contaminates the surrounding atmosphere (Alsaleh and Sattler, 2014). Pyrolysis oil, char and gas
have been reported to be decomposition products of waste tyres (Martínez et al., 2013). The
main components, hydrogen and hydrocarbons (C1–C4) having high heating value were reported
to be present in produced gases, so it shows strong potentioal to be used as a fuel for diesel
engines (Williams, 2013).
According to Rodriguez et al., (2001), there is a disposal problem of solid tyre waste because of
its nondegradability and complex structure containing steel cord, carbon black, and other
complicated chemical compounds. Disposing of waste tyres in land fill is not a proper root of
dumping of wastes. A major part of the wastes may be converted into useful energy or fuel using
standard methods. Various researchers have been trying to develop appropriate methods of
pyrolysis like steam pyrolysis and fluidised bed pyrolysis (Kaminsky and Mennerich, 2001) and
flash pyrolysis (Edwin Raj et al., 2013). As reported by Murugan et al., (2008) and Dogan et al.
(2012), many researchers around the world have studied the behavior of diesel engines with
pretreated waste tyre oils to use the oil as an alternative, sustainable and renewable energy.
29
1.2.9.5.5 Waste Cooking Oil
Vegetable oil obtained after frying or cooking food items is referred to as waste cooking oil
(WCO). After repeated frying of vegetable oil for preparation of food becomes unsuitable for
further edible consumption (Nantha et al., 2014). Various disposal problems such as soil and
water pollution, disturbance to the aquatic ecosystem and human health concerns. Instead of its
harmful environmental disposal options, WCO can be effectively used for biodiesel production.
For the preparation of soap and additives for engine oils, the collected WCO can also be used
(Maurizio et al., 2014). Many researchers throughout the world have documented the successful
conversion of WCO into biodiesel (Nabanita et al., 2014). In comparison to conventional diesel,
the biodiesel derived from waste cooking oil contributes to lower greenhouse-gas emissions
(Chang et al., 1996). According to Lapuerta et al. (2005) and Ramadhas et al, (2005), various
scientists have recommended the suitability WCO and its derivatives to be converted into
biodiesel fuel.
1.2.10 Used Oil Regeneration Technologies
1.2.10.1 Vacuum Distillation
The hydrocarbon compounds with medium to high molecular weight cannot be separated by
atmospheric distillation; such compounds are subjected to vacuum distillation to be fractionated.
These types of hydrocarbons commonly requires a high temperature for distillation. Typically,
the pressure ranging from 10 to 50 mm Hg is used in vacuum distillation (Byrant, 1989).
According to U.S. Department of Energy (1983) and Audibert (2006), the organic fuel distilled
using this process might be used as heating oils at the refineries or sold as fuels.
30
1.2.10.2 Atmospheric Distillation
This type of distillation is suitable for the compounds having low molecular weight like petrol,
diesel, solvents and water. Such compounds are subjected to atmospheric distillation at
temperature of 160 to180oC. The water separated from used lubricants can be further treated and
used for cooling the plant or discharged into surface water (CEPA, 1994).
1.2.10.3 Adsorption Process
Generally, bauxite, silica gel and activated clay are being used as adsorbents to separate out
impurities from waste lubricanting oils. To remove color and odor of waste lubricants,
commonly, activated clay is used after the pretreatment process. The clay used in the process can
be recycled again under the controlled temperature of 150 to 330oC (Audibert, 2006). When the
adsorbent is saturated with impurities, then the adsorption efficiency might decline. (Mytol,
2009).
1.2.10.4 Sulfuric Acid Process
For refining and regeneration of oils (crude petroleum and animal oils), the conventional sulfuric
acid method has been used since the 1950s. According to U.S Department of Energy (1983), six
to eight percent of concentrated H2SO4 is used to oxidize the impurities in waste lubricating oil.
It has been observed from the study reports of the California Integrated Waste Management
Board (2009) and Audibert (2006), the operating parameters of acid treatment, such as
temperature and residence time, should be controlled carefully, so that oxidation of hydrocarbon
compounds in the waste lubricants might be prevented. The acid treatment is usually carried out
at a temperature of 30 to 40oC for 20 to 30 minutes. The acid treatment plant has a moderate
yield of production. Extremely hazardous and pollutant emissions are produced during the
process of acid treatment (Mytol, 2009; Peotrof Refining Technologies, 2009; NHDC, 2009).
31
Most commonly, produced acid sludge is nuetrilized with CaO or lime. The acid sludge can be
considered as a hazardous waste even after neutralization because its complete neutralization is
not possible (Hamad, et al., 2002). According to Mytol (2009), the following two problems are
also encountered during acid treatment process:
i) There is high disposal cost of acid sludge; and
ii) It is difficult to find a safe location of sludge dumping.
Therefore, for the industries, this technology is less favourable (U.S. DOE, 1983).
1.2.10.5 Hydroprocessing
Waste lubricants might undergo hydroprocessing or hydrotreatment. This process involves two
steps. In first step, removal of impurities such as metals and metalloids takes place, whereas in
second step removal of sulfur and nitrogen compounds occurs. For the removal of impurities,
waste lubricants are mixed with catalysts (like cobalt-molybdenum with alumina) and hydrogen
is passed through the mixture.
Table 1.11 Most commonly found re-refineable and not re-refineable oils by the Canadian
Sr.
No. Oils to be re-refined Oils not to be re-refined
1 Transmission oils LVI and MVI oils
2 All diesel and gasoline crankcase oils Biphenyls and Polynuclear
3 Hydraulic oils (non-synthetic) Halides
4 High Viscosity Index Oils Oils Containing Polychlorinated
5 Transformer oils Brake fluids
6 Gear oils (non-fatty) Synthetic oils
7 Compressor oils Asphaltic oils
8 Dryer Bearing oils Fatty oils
9 Machine oils (non-fatty) Bunker oils
10 Quenching oils (non-fatty) Form Oils
11 Grinding oils (non-fatty) Any kind of solvent
32
Pretreatment of the waste lubricants is carried out to avoid the saturation of the catalysts.
According to Audibert (2007), by improving the catalyst structure (chestnut-bur structure) higher
metal removal rate up to 60% was observed in comparison to 20% removal with former design.
In the second stage, nickel-molybdenum catalyst along with alumina is used to remove nitrogen
and sulfur compounds from waste lubricants as reported by Audibert (2007). Most commonly
found re-refineable and not re-refineable oils by the Canadian Association of Re-Refiners (CAR,
2011) are given in Table 1.11.
1.2.10.6 Centrifugation
Due to the dispersive action of additives, it is very difficult to settle the water and suspended
impurities in waste lubricants by means of gravity. Use of centrifugal force is the solution to
settle suspended particles and water impurities present in waste lubricating oil. The gravitational
force is a thousand times less than the centrifugal force as reported by Audibert (2006). Even
though, from used lubricants, all impurities cannot be removed by centrifugation, the process is
sufficient to remove large and heavy impurities like metal fragments very easily. Moreover, the
process of centrifugation is very helpful to isolate the acid sludges formed during acid treatment
phase. A considerable amount of treated lubricant becomes soaked up in clay waste used in acid
treatment with help of centrifugation process.
1.2.10.7 Propane Extraction
Under high pressure of 10 atm waste lubricants are purified by removing impurities through
precipitation using propane as a solvent (Mytol, 2009). Propane extraction is economical as
compared to other technologies, because propane can be recycled and reused again. Usually, a
pretreatment is required for this process for the removal of large impurities to avoid plant
clogging (Audibert, 2007).
33
1.2.10.8 Thin Film Evaporation
According to Audibert (2007), over the hot surface in thin film evaporator, waste lubricants are
spread in the form of a layer. From the waste lubricants, depending upon the design of the
system, the oil phase is evaporated from the hot surface and collected at the condenser next to
evaporator or inside the evaporator.
1.2.11 Refining Processes of Mineral Base Oils
1.2.11.1 Separation Technology
Lubricant feedstocks generated through atmospheric distillation units and vacuum distillation
units still contain impurities such as resins, wax and asphaltenes, which need to be separated out.
In this technology, the beginning step is deasphalting. According to Speight (2007), for
separating out asphaltene and resin type impurities, propane deasphalting is commonly
employed. Such type of deasphalted mineral base oil is referred to as waxy raffinate. The refinate
is hydrocarbon mixture having longer chains of carbon atom (C-38 and higher). The raffinate is
further processed into various chemical treatments and is converted into mineral base oils as
shown in Figure 1.3 (Lynch, 2008). The second phase is the removal of aromatic compounds
using furfural extract ion. Third phase is the removal of wax by using MEK (methyl ethyl
ketone). The last phase is the hydrofinishing or clay treatment. The flow diagram of the
separation process is given in Figure 1.3.
34
Lubricant feedstock from Vacuum Distillation Unit
Asphalt residue
De asphalted Oil
Aromatic Extract
Waxy raffinate
Wax
De waxed oil
Mineral Base Oil
1.2.11.2 Conversion Technology
This technology includes hydrocracking, hydrofinishing and hydrodewaxing. This method is
entirely different from the separation process. In this technology, aromatic hydrocarbons are
Propane
Deasphalting
Furfural
Extraction
MEK
Dewaxing
Hydrogen
Finishing
Figure 1.3 Simplified Flow Diagram of Separation System
35
cracked catalytically in the cracker unit (hydrocracker) and after the cracking process, the
aromatic compounds are converted into saturated paraffinic hydrocarbons using high pressure
(3000psi) and hydrogen gas. Hydrodewaxing is carried out soon after cracking process.
Hydrodewaxing, in the presence of hydrogen converts waxy straight chain paraffins (n-paraffins)
into branched chain paraffins (iso-paraffins). The last phase is the hydrofinishing. In
hydrofinishing, the recovery of hydrogen takes place and saturation of remaining unsaturated
hydrocarbon compounds occurs. Flow diagram of conversion technology is given in Figure-1.4.
Lubricant feedstock from Vacuum Distillation Unit
Mineral Base Oil
Propane
Deasphalting
Hydro
cracking
Hydro
dewaxing
Hydrogen
Finishing
Figure 1.4 Simplified Flow Diagram of Conversion System.
36
1.2.12 Biodiesel and Its Blends
1.2.12.1 Biodiesel
A mixture of different fatty acid methyl esters is commonly referred as biodiesel. The biodiesel
fuel is an environment friendly renewable energy resource. The energy demands are going to be
increased day by day because of abrupt increase in population over the globe. As the natural
reserves of petroleum, natural gas and coal are going to be depleted day by day, the search for
alternative fuels is necessary to fulfill the energy needs. Regarding alternative fuels, biodiesel
has a great potential to be used in diesel engines in place of petroleum diesel. The term
“biodiesel” is referred to as mono-alkyl esters of long chain fatty acids having renewable and
biodegradable capabilities. Most commonly biodiesel is derived from animal fats, vegetable oils,
animal fats, domestic and restaurant frying oils (Fernando et al., 2006; ASTM, 2008). The main
feedstocks of biodiesel such as animal fats and vegetable oil are referred as triglycerides. These
triglycerides are converted into monoesters (biodiesel) through an enzyme or acid or base
catalyzed reaction being known as transesterification. In this type reaction, triglyceride is treated
with an alcohol using a catalyst. Kalnes et al. (2007) reported that the catalyst might be an acid,
base or an enzyme. As a result of this process, glycerine and fatty acids alkyl esters (biodiesel)
are produced in the form of two separate layers. Glycerine, the byproduct produced is also
known as glycerol. Biodiesel is also known as fatty acid methyl esters (FAME), as methanol is
most commonly used as reactant during transesterification reaction to produce biodiesel
(Mikkonen, 2008).
1.2.12.2 History of Biodiesel
According to the reported studies, the transesterification reaction is not the latest reaction to be
used for biodiesel production (Shay, 1993). In 1853, a German Scientist, Rudolph Diesel,
37
presented his hypothesis as “The theory and construction of a rational heat engine”. High
pressure was created in the engine with help of compressed air and piston. The engine was
capable to run with various vegetable oils. According to Seddon (1942), Dr. Diesel first designed
and presented his diesel engine in Paris, at the occasion of World’s Fair in 1911, initially using
100% pure peanut oil to run his engine. Dr. Diesel in the year 1911 stated, “The diesel engine
can be fed with vegetable oils and would help considerably in the development of the agriculture
of the countries which use it.” In 1912, Dr. Diesel said, “the use of vegetable oils for the engine
fuels may seem insignificant today.” The engine was modified to run on petroleum diesel after
the death of Dr. Diesel in 1913 (Biofuels Coop., 2016). First of all the biodiesel fuel derived
from base catalyzed transesterification reaction was used in heavy-duty vehicles before World
War-II in South Africa (Shay, 1993; Seddon, 1942).
In the University of Brussels, Belgium, the first reported research work on biodiesel was
performed on August 31, 1937. During the summer of 1938, a bus fueled with biodiesel derived
from palm oil was run in Brussels. The performance of the vehicle (bus) was found satisfactory.
Much difference of viscosity and biodiesel derived from palm oil was observed. The cetane
number was reported as 50-57.5 for petro-diesel and as 83 for biodiesel.
In the mid 1970s, people of the world encountered a fuel shortage. Since that time, production of
biodiesel was promoted as an alternative fuel in competition to petroleum derived diesel.
Transesterification of sunflower oil was carried out to minimize the viscosity of the virgin oil.
The commercialization period of biodiesel was reported as 1980 and 1981 (Shay, 1993). At
present, more than 120 plants are converting various vegetable oils into biodiesel in European
countries (Australia, Sweden, France, Italy and Germany). They are producing around 6.1
million tons of biodiesel every year.
38
1.2.12.3 Beneficial Aspects of Biodiesel
In the start of the 1980s, biodiesel was proposed to be used in place of petroleum diesel in
compression ignition engines. Compared to petroleum diesel, the beneficial aspects of biodiesel
are given below as reported by Huang et al., (2010), Antolin et al., (2002), Vicente et al., (2004)
and Tomasevic et al., (2003).
• Biodiesel is much cleaner burning fuel, produced from domestic renewable
resources.
• Biodiesel can be used in compression ignition engine without any modification.
• Biodiesel can be used as pure B100 or can be used by blending it with petro-
diesel in any proportion without adding additives.
• Biodiesel is non-toxic, biodegradable fuel and reduces the emission of many
harmful pollutants from diesel engine.
• Biodiesel reduces the unburned hydrocarbons (93% less) and CO (50% less).
• Biodiesel is low in sulphur contents, so sulphur dioxide emissions are reduced.
• As biodiesel is based upon plant sources so it reduces up to 80-90% emissions of
carbon dioxide greenhouse gas to the atmosphere.
• Biodiesel may increase or decrease the nitrogen oxide level but is less than petro-
diesel fuel level.
• Biodiesel has non-offensive smell and does not cause eye irritation.
• Biodiesel is highly biodegradable, renewable and environmentally friendly fuel as
it causes less pollution.
• Biodiesel has very high values of certain numbers like cetane number, flash point,
octane number (more than 100) etc. because of its high oxygen contents. These
39
high values make biodiesel a more effective and efficient fuel; contribute to easily
cold starting of engine; causing low noise and knocking.
• Biodiesel has high lubricating nature than petro-diesel engine fuel. As it is much
better lubricant it can increase the life of engines.
• Biodiesel promotes the field of agriculture as it is much more attractive for the
farmers of developing countries as a new source of income and for industrial
revitalization.
• Biodiesel decreases the dependency on imported crude oil and others refined
fractions of petroleum.
• Biodiesel provides high energy security and helps the economy of those countries
which are deficient in energy resources.
1.2.12.4 Harmful Aspects of Biodiesel
Some of the harmful effects are listed here under as described by Ramadhas et al., 2005; Al-
Zuhair, 2007; Gryglewicz et al., 2003; Ivanoiu et al., 2010 and Lotero et al., 2005.
• Biodiesel is much more expensive than petro-diesel fuel if raw material is not
obtained from waste resources.
• Biodiesel production needs more vegetable oil crops, field for agriculture, and
energy of sowing, fertilizing and harvesting.
• As biodiesel cleans the dirt from the engine, so in the presence of biodiesel fuel,
all the dirt in engine becomes collected in the fuel filter, increasing clogging.
Therefore, it is necessary to change the filter after several hours of running the
engine with biodiesel.
• As biodiesel is not readily available in all the countries of the world, its
distribution needs more improvements.
40
• Biodiesel has high viscosity and low volatility as compared to petro-diesel fuels.
• Biodiesel has higher values of cloud point and pour point which lower the engine
speed and power.
Overall, biodiesel comparison with other petro-diesel fuels clearly supports its specific features
and qualities.
1.2.12.5 Transesterification Process
Biodiesel is a very versatile transport fuel. In rural regions of developing countries, biodiesel is
produced from local raw material or collection of used vegetable or frying oil. Most commonly,
there are three basic routes of biodiesel production from oils and fats (Zanzi et al., 2006).
• Base catalyzed transesterification of the oil
• Acid catalyzed transesterification of the oil
• Conversion of oil to its fatty acids and then to biodiesel.
Transesterification reaction is a stage of converting oil or fat into methyl or ethyl esters of fatty
acid, which constitutes to biodiesel. Biodiesel is obtained through the reaction of triglycerides of
vegetable oils with an active intermediate formed by the reaction of an alcohol with a catalyst.
The general reaction for obtaining biodiesel through transesterification is (Duarte et al., 2007).
Oil or Fat + Methanol ⎯⎯→ Methyl Esters +Glycerol (Equation 1.1)
or
Oil or Fat + Methanol ⎯⎯→ Ethyl Esters +Glycerol (Equation 1.2)
Various types of alcohols, preferably, those with low molecular weight might be employed in
transesterification reactions. Technically, transesterification with methanol is more viable in
comparison to ethanol. However, ethanol might be used only in its anhydrous (with a water
content of less than 2%) condition because the water acts as an inhibitor during the reaction.
41
Another advantage in using methanol is the separation of glycerine from the reactive medium
because in the case of synthesis of the methylated ester, this separation may be easily obtained
through simple decantation (Duarte et al., 2007). The simplest procedure of manufacturing
biodiesel through transesterification with vegetable oil is shown in Figure 1.3.
This reaction can be catalyzed by acids, enzymes or alkalis. Alkalis include potassium
hydroxide, sodium hydroxide, carbonates and corresponding potassium and sodium alkoxides,
for example potassium or sodium methoxide, sodium ethoxide, sodium butoxide and sodium
propoxide. Sulphuric acid, hydrochloric acid and sulfonic acids, are generally used as acidic
catalysts. In the industry, transesterification is generally done with alkali media, because they
CH3OH+
NaOH
Solution
Vegetable
Oil
Transesterification
60 to 70 oC, 1 hour
Methyl Ester/Glycerol
Crude Biodiesel
Refining
Glycerol Separation
Biodiesel
Figure 1.3 Procedure of manufacturing biodiesel through transesterification reaction.
42
present better yield and lower reaction time (Duarte et al., 2007). The production of biodiesel by
transesterification of vegetable oil uses the following steps (Zanzi et al., 2006).
1.2.12.5.1 Mixing of Alcohol and Catalyst
Potassium hydroxide (KOH) and sodium hydroxide (NaOH) are generally used as alkaline
catalysts with methanol (CH3OH) for production of biodiesel (May et al., 2005).
1.2.12.5.2 Reaction
The alcohol/catalyst mixture is charged into a closed reaction vessel and the vegetable oil is
added (May et al., 2005). The reaction mixture is heated to the boiling temperature of the alcohol
(normally 50 to 60 °C) and is refluxed for a certain time period under agitation. In relatively
short times, around 60 minutes, the reaction mixture has a very good conversion efficiency of
96% to 99%. When agitation is stopped the reaction mixture separates into two layers, upper
layer (methyl esters or biodiesel) and a lower layer of glycerol diluted with un-reacted methanol
(Duarte et al., 2007).
1.2.12.5.3 Separation of Glycerine and Biodiesel
Once the reaction is complete, two major products are produced: glycerine and biodiesel, methyl
ester (Zanzi et al., 2006). Quantity of produced glycerine varies according to the process used,
the vegetable oil used and the amount of alcohol used. Both glycerine and biodiesel products
have a substantial amount of the excess alcohol that is used in the reaction (Duarte et al., 2007).
1.2.12.5.4 Removal of Alcohol
The fatty ester produced in the upper layer is neutralized and vacuum distilled for removal of
excess methanol (May et al., 2005).
43
1.2.12.5.5 Glycerine Neutralization
The by-product glycerine contains unused catalyst and soaps in the upper layer that are
neutralized with phosphoric acid resulting in potassium phosphate, if potassium hydroxide is
used as a catalyst. The crude glycerine is sent for storage (Zanzi et al., 2006).
1.2.12.5.6 Methyl Ester Washing
The methyl ester produced from the reaction is then washed with hot water and separated out by
centrifugation (May, et al., 2005). The transesterification process, involving transformation of
the large branched triglyceride molecule into smaller straight chain molecules is shown in Figure
1.4 (Rodjanakid et al., 2004).
Figure 1.4 Transesterification reaction of triglycerides and methanol in manufacturing of biodiesel
1.2.12.6 Sources of Biodiesel in Different Countries
Using transesterification, biodiesel is commonly produced from animal fats and vegetable oils. In
different countries, the major sources to produce biodiesel are different. Mostly sunflower,
soybean, rapeseed, olive, jatropha, palm, peanut, safflower, cottonseed, canola and corn oil are
considered as potential sources for the production of biodiesel. On a commercial scale, in various
countries of the world, a variety of waste vegetable oils, virgin vegetable oils, animal fats like
44
lard, tallow and yellow greases and some non-edible oils like jatropha, tall, neem and castor oil,
etc. are extensively employed to prepare the biodiesel.
Table 1.12 Sources of biodiesel in different countries.
Sr. No. Country Sources of biodiesel
1 Brazil Soybean
2 Spain Linseed oil/Olive oil
3 USA Soybean
4 Germany Rapeseed oil
5 Italy Sunflower oil
6 Australia Animal fat/Beef tallow
Rapeseed oil
7 Malaysia Palm oil
8 Canada vegetable oil/animal fat
9 China Guang pi
10 France Sunflower oil
11 India Jatropha
12 Ireland Animal fat/Beef tallow
13 Europe Rapeseed oil/Sunflower oil
14 Ghana Palm oil/Coconut oil
15 Indonesia Palm oil
16 Turkey Waste frying oil
45
Table 1.12 shows the major sources of biodiesel in different countries of the world (Lakshmanan,
et al., 2010 and Lakshmanan, et al., 2011).
The major problem for the production of biodiesel is the limited availability and high cost of
vegetable oils. The estimated production cost of biodiesel is 1.5 times greater than that of petro-
diesel if waste resources as raw material are not employed. As the population growth rate of all
the countries in the world is increasing day by day, food consumption is also increasing
respectively in each country. Some of the developed countries like Turkey are recycling their
waste frying oils (WFOs) to produce biodiesel. WFOs provide high potential as low cost material
for the production of biodiesel (Rashid et al., 2008). It has been noted that the price of waste
frying oil is 2-3 times less than virgin vegetable oil (Phan et al., 2008; Encinar et al., 2007;
Bhatti et al., 2009).
1.2.12.7 Waste Frying Oil as a Biodiesel Feedstock
In European contries, it is estimated that 17 million tons vegetable oil is being utilized per
annum. This amount of vegetable oil is increasing about 2% after every year (Agriculture and
Food Development, 2000). This value shows that there are large amount of waste frying oil
(WFO) resources. But the major drawback is that the European countries do not pay attention
towards these waste frying oil potential, so, very less amount of this WFOs can be collected
every year. When these waste oils are poured into water, they block the sewerage system and
contaminate the waste water. It is reported, in USA, 40% of the blockage of sewerage system is
due to waste frying oil poured into kitchen sinks (Agriculture and Food Development, 2000).
These WFOs and animal fats are not suitable for the soap formation as they cause health
problems in human beings. Therefore, these waste frying oils may properly be utilized as
feedstocks for the biodiesel production. The conversion of these WFOs into biodiesel also
46
reduces the cost of commercial biodiesel and eliminates the soil and water pollution problems.
However, the fuel quality parameters and physico-chemical properties of biodiesel do not remain
as such the conventional petro-diesel fuels. So in order to get biodiesel of good fuel quality
parameters, it is essential to perform the process of transesterification under the given standard
conditions.
1.2.12.8 Frying Process of Vegetable Oils
In the presence of air and moisture, when the vegetable oils are continuously subjected to high
temperature during frying, they undergo three major degradation effects as mentiond in below
sections.
1.2.12.8.1 Oxidative Effects
Oxidative effects are due to the oxidation reactions of oil contents because of the presence of
oxygen in the atmosphere. The products formed due to these reactions are oxidized to
monomeric, dimeric and oligomeric triglycerides and volatile organic compounds such as
ketones and aldehydes.
1.2.12.8.2 Hydrolytic Effects
These effects are due to the presence of water released by the food or moisture of fried food. The
major products due to these hydrolytic reactions are free fatty acids (FFA), monoglycerides and
diglycerides.
1.2.12.8.3 Thermal Effects
Thermal effects are due to high temperature range which causes the production of dimeric and
polymeric triglycerides with ring structures during the frying process of vegetable oils (Gertz
2000; Stevenson et al., 1984; Choe et al., 2007; Tyagi et al., 1996). All these degradation
reactions during frying process alter the physico-chemical properties of frying oil. All these
47
reactions increase the viscosity, density, FFA content, polymerized triglycerides, total polar
material (TPM) and reduces the smoke point, degree of unsaturation, etc. Total content of TPM
of frying oil indicates its degradation levels. Degradation level increase with increase in
temperature and frying time. Some physico-chemical properties are also used to monitor the
quality of WFOs (Aladedunye et al., 2009; Knothe et al., 2005).
1.2.12.9 Vegetable Oils Used in Present Research
The present research work is based upon four different vegetable oils which are subjected to
frying process to get waste frying oils (WFOs). These waste frying oils of different sources and
their virgin oils are further undergoing transesterification process to produce biodiesel:
Sunflower oil
Soybean oil
Corn oil
Canola oil
1.2.12.9.1 Sunflower (Helianthus Annuus) Oil
Sunflower oil is mainly non-volatile oil extracted from sunflower (Helianthus annuus) seeds. It
is commonly used in food as frying oil. Sunflower oil was first commercially produced in the
Russian Empire in 1835. At present time it is extensively being produced in Russia and
Argentina (The United Nations, 1988). It is mainly a triglyceride and consists of following
constituents according to British pharmacopoeia (British Pharmacopoeia, 2005):
Linolenic acid (polyunsaturated omega-6) (48-74%)
Oleic acid (monounsaturated omega-9) (14-40%)
Palmitic acid (saturated) (4-9%)
Stearic acid (saturated) (1-7%)
48
The characteristics of sunflower oil (Chu, 2004; Abramovic et al., 1998) are presented in Table
1.13.
Table 1.13 Characteristics of Sunflower Oil (SF Oil)
Sr. No. Physical Property Value /Unit
1 Smoke Point (refined SF oil) 232 oC
2 Smoke Point (unrefined SF oil) 107 oC
3 Pour Point -12 to -17oC
4 Flash Point ≈ 315 oC
5 Cloud Point ≈ -9 oC
6 Density (25oC) 0.9188 g/cm3
7 Saponification Value 188-194
8 Iodine Value 120-145
9 Viscosity (20oC) 4.914 cSt.
10 Refractive Index (20oC) ≈ 1.4646
11 Unsaponifiable Matter ≈ 1.5- 2.0 wt.%
The waste frying oil derived from sunflower oil is now subjected to transesterification to produce
biodiesel in different countries of Europe.
1.2.12.9.2 Soybean Oil
Globally, the soybean (USA) or soyabean (UK) is cheap and readily available oil resource.
Soybean oil is extracted from the soyabean seed. The main producers of the soybean oil are the
US (35%), Argentina (19%), Brazil (27%), India (4%) and China (6%). This oil is mainly used in
industrial applications (Circle et al., 1972; Growing Crush Limits, 2016). It is a clear pale yellow
liquid. It consists of followings constituents (British Pharmacopoeia, 2005):
Saturated fatty acids of chain length less than C-14 up to 0.1%
Palmitic acid (9-13%)
Linolenic acid (5-11%)
Stearic acid (2.5-5%)
Oleic acid (17-30%)
49
According to British Pharmacopoeia, 2005, Detwiler et al., 1940, Ali, 1995, and Wesolowski,
1993, the physical properties of soyabean oil are given in Table 1.14.
Table 1.14 Physical properties of soybean oil.
Sr. No. Physical Property Value /Unit
1 Smoke Point ≈ 245 oC
2 Pour Point -12 to -16oC
3 Flash Point ≈ 224 oC
4 Cloud Point ≈ -9 oC
5 Density (20oC) 0.9165 to 0.9261
6 Saponification Value ≈ 190.6
7 Iodine Value ≈ 130
8 Viscosity (20oC) ≈ 5.58 to 6.22 cSt.
9 Refractive Index (20oC) ≈ 1.4733 to 1.4760
10 Unsaponifiable Matter ≈ 1.50%
It is very popular edible oil having high smoke point and health benefits. It is widely used for
baking, cooking and frying. In advanced countries, the waste frying oil of soybean is now
commercially being used to produce biodiesel.
1.2.12.9.3 Corn Oil (Maize Oil)
Due to its high smoke point, corn oil is a highly valuable frying oil used in cooking. Source of
the extraction of corn oil is the germs of maize (corn). Corn oil is used as major source for
biodiesel production. It is generally less expensive than other vegetable oils. Waste frying corn
oil is very less expensive source of biodiesel production. Some industries also consume corn oil
to produce soap, paints, inks, rust proofing for metal surfaces, textiles, insecticides and
pharmaceutical products. Maximum amount of corn oil is refined for human consumption and
for use by food industries. Refined form of corn oil has neutral flavor, high smoke point and can
withstand heat. Modern research has shown that its human consumption as a food has very
healthy benefits (Erickson, 2006).
50
It consists of following constituents (Hauman, 1985; Hegested et al., 1993; Iacono et al., 1993):
Linoleic 18:2 (polyunsaturated having 54-60 g/100g of oil)
Linolenic 18:3 (polyunsaturated having 1 g/100g of oil)
Palmitic 16:0 (saturated having 11-13 g/100g of oil)
Stearic 18:0 (saturated having 2-3 g/100g of oil)
Oleic 18:1 (monounsaturated having 25-31 g/100g of oil)
Similarly some of the physico-chemical properties of corn oil are given in Table 1.15 (Chu,
Michael, 2004; Abramovic et al., 1998; Detwiler et al., 1940; Ali et al., 1995).
Table 1.15 Physical Properties of Corn Oil
Sr. No. Physical Property Value /Unit
1 Smoke Point ≈ 232 oC
2 Pour Point ≈ -20oC
3 Flash Point ≈ -330 oC
4 Cloud Point -12 oC
5 Density (20oC) 0.925 g/cm3
6 Saponification Value 189-195
7 Iodine Value 122- 131
8 Viscosity (20oC) 5.55 to 6.20 cSt.
9 Refractive Index (20oC) ≈ 1.4722 to 1.4755
10 Unsaponifiable Matter ≈ 1.20% per100g
1.2.12.9.4 Canola Oil
Major sources of extraction of canola oil are Brassica rapa and Brassica napus. In bulk quantity,
it is produced in Canada. It is completely safe and is the healthiest of all commonly used cooking
oils and fats. It is highly recognized by many health professional organizations such as American
Dietetic Association (ADA) and American Heart Association (AHA) due to its heart health
benefits. Composition of fatty acids in canola oil can be modified to minimize the content of
51
erucic acid and to enhance the level of oleic acid (Lorgerill et al., 2006; Halfhill et al., 2002). Its
fatty acid composition is as follows (USDA, 2008; Canola Council of Canada, 2016):
Saturated fatty acids 7.0 %
Linolineic acid 9 % - 11%
Oleic acid (monounsaturated fatty acids) 61 %
Stearic acid 2%
Palimitic acid 4%
It also contains some level of vitamin E and phenolic resins.
Some of its physical properties are in the given Table: 1.16.
Table 1.16 Physical properties of canola oil
Sr.
No.
Physical property Values/units
1 Smoke point 220-230°C
2 Pour point - 18°C
3 Flash point 275-290°C
4 Density (20°C) 0.914-0.917 g/cm3
5 Cloud point -8 to -12 °C
6 Refractive index (40°C) 1.465-1.467
7 Viscosity (25°C) 5.6 cSt
8 Saponification value 189-195
9 Iodine value 110-120
10 Unsaponifiable matter 0.5-1.2 % per 100g
In comparison to other cooking oils, the canola oil is rich in oleic acid, which makes it more
competitive. Anyhow, its waste frying oil is also a valuable and cheap source to produce
biodiesel through transestrerification process.
52
1.2.12.10 Biodiesel Blends
Blends of biodiesel and conventional hydrocarbon-based diesel are produced by mixing biodiesel
and petroleum diesel in suitable proportions under appropriate conditions. Much of the world
uses a system known as the "B" factor (Fernando et al., 2006) to state the amount of biodiesel in
any fuel mixture. Say for example:
2% biodiesel and 98% petro diesel is famous as B2
5% biodiesel and 95% petro diesel is known as B5
20% biodiesel and 80% petro diesel is called B20
100% biodiesel is referred to as B100.
The most common biodiesel blends reported in the literature are discussed below.
1.2.12.10.1 B100 Blend
The 100% biodiesel is known as B100. It may release deposits accumulated in fuel chamber and
it can clean a vehicle's fuel system because it has a solvent effect. The release of these deposits
may initially clog filters and require filter replacement (Fernando et al., 2006). It may require
special handling and equipment modifications. To avoid engine operational problems, B100
must meet the requirements of (ASTM, 2008), standard specification for Biodiesel Fuel. Use of
B100 as a fuel for diesel engines can greatly reduces other toxic emissions. B100 is less common
than B5 or B20 due to a lack of regulatory incentives (Fernando et al., 2006).
1.2.12.10.2 B20 Blend
B20 (20% biodiesel, 80% petroleum diesel) is the most common biodiesel blend (Kalnes et al.,
2007). B20 is a well known biodiesel blend because it represents a good balance of cost, toxic
emissions, materials compatibility, cold-weather performance, and ability to act as a solvent
(Mikkonen et al., 2008). Biodiesel blend B20 must meet prescribed quality standards (ASTM,
53
2008). In comparison to petroleum diesel, the biodiesel contains about 8% less energy per gallon
However, most of B20 users report no noticeable difference in fuel economy and performance.
Greenhouse gas and air-quality benefits of biodiesel are roughly commensurate with the blend.
In comparison to B100, the use of B20 blend provides about 20% more benefits (Kalnes et al.,
2007).
1.2.12.10.3 B5 Blend
A B5 blend is a mixture of 5% biodiesel and 95% petroleum derived diesel. Associated with
biodiesel, it is one of the most common blends due to its utilization in state or municipal
mandates. The use of B5 blend in diesel engines has been approved by many engine
manufactures (ASTM, 2008). ASTM has revised its statements so that B5 blend may be treated
just like petroleum diesel (ASTM, 2008).
1.2.12.10.4 B2 Blend
B2 is a blend of 2% biodiesel, 98% petroleum derived. It is one of the most common blends
associated with biodiesel. It is used in fleets, tractor trailers, off road heavy equipment, on road
light duty fleets (Rashid et al., 2008).
1.2.12.11 Emission Characteristics of Biodiesel
Biodiesel blends in different proportions to petroleum diesel have shown significant
improvement in terms of greenhouse gas (GHG) emissions. It was experimentally observed that
on combustion of biodiesel blends, the level of smoke emissions, carbon monoxide (CO),
particulate matter (PM) and carbon dioxide (CO2) were reduced significantly; whereas the
amount of oxides of nitrogen (NOx) was increased (Rashid et al., 2008). Since biodiesel is
oxygenated, engines have more complete combustion in comparison to ordinary diesel.
54
1.2.12.12 Emission Characteristics of Biodiesel Blends
1.2.12.12.1 Particulate Matter (PM)
Particulate matter (PM) is a complex mixture of extremely small particles and liquid droplets.
Particulate matter is also called particulate pollution is made up of a number of components,
including acids (such as sulphates and nitrates), metals, organic chemicals and dust particles
(Bhatti et al., 2009). Overall, 30-47% lower PM emissions were observed in biodiesel in
comparison to petroleum diesel. Breathing particulate matter has been found to be a human
health hazard (Bhatti et al., 2009).
1.2.12.12.2 Hydrocarbons (HC)
The exhaust emissions of total hydrocarbons (a contributing factor in the localized formation of
smog and ozone) are on average 20-67 percent lower for biodiesel than diesel fuel. In
comparison to petroleum diesel, reduced HC emissions were observed in biodiesel fuel blends
(Bhatti et al., 2009).
1.2.12.12.3 Nitrogen Oxides (NOx)
Mono-nitrogen oxides, nitric oxide (NO) and nitrogen dioxide (NO2) are termed as NOx. They
are produced from the reaction of nitrogen and oxygen gases in the air during combustion at high
temperatures (Kumar, 2012).
Table 1.17 Commonly found biodiesel blends emissions for a heavy duty engine
Sr.
No. Type of Emission B20 B100
1 Total Unburnt Hydrocarbons (HCx) -20 to -2.2% -67 to -20%
2 Particulate Matter (PMx) -12 to -6.4% -47 to -32.41%
3 Carbon Monoxide (CO) -12 to -6.9% -34.50 to 48%
4 Oxides of Nitrogen (NOx) -2.0 to +2.0% 10 to 13.35%
55
The oxides of nitrogen (NOx) are precarious pollutant emissions, which are produced when the
fuel is burnt at high temperature causing dissociation of N2, which ultimately leads to the
formation of nitric acid (Encinar et al., 2007). NOx increases directly with the degree of blending
as NOx emission increases with increased temperature (Huang et al., 2010).
1.2.12.12.4 Smog Formation
The overall ozone (smog) forming potential of biodiesel is less than diesel fuel. The ozone
forming potential of hydrocarbon emission is nearly 50% less than that measured for diesel fuel
(www.epa.gov/otaq/models/analysis/biodsl/p02001.pdf. Biodiesel Emissions).
1.2.12.12.5 Carbon Monoxide
Carbon monoxide (CO) is an intermediate product of combustion, formed in the earlier stages of
the oxidation process before full conversion in to CO2. It is emitted in the exhaust stream when
its progression to CO2 is not complete due to cooling of fuel flame temperature, or when the
engine operation is too fuel rich. The exhaust emissions of carbon monoxide from biodiesel are
48 - 50% lower than from the petroleum diesel (Encinar et al., 2007; Huang et al., 2010).
1.3 Aims and Objectives
Regeneration and reuse of waste oils is a better way to generate energy which would help to
decrease waste oil disposal problems and reduce burden of fuel import in Pakistan. This would
conserve the valuable crude oil reserves of the country and reduce the environmental pollution
threats. The objectives of this Ph.D research are as follows:
i. To evaluate environmental impacts associated with waste lubricating oils.
ii. To assess and compare the physico-chemical properties of waste and regenerated
petroleum based lubricants.
56
iii. To develop novel, cheap and environmentally friendly technology for regeneration of
waste lubricating oils.
iv. To evaluate existing conventional technologies which are being used for regeneration of
waste lubricating oils.
v. To characterize and compare the properties of the regenerated waste lubricants with that
of fresh lubricants using international ASTM procedures.
vi. To prepare and characterize biodiesel oil obtained from waste cooking oils using Fourier
Transform Infrared (FTIR) spectroscopy.
vii. To carry out catalytic and thermal cracking of regenerated waste lubricants to produce
an alternative fuel for diesel engines.
viii. To investigate combustion, performance and emission characteristics of a diesel engine
operated with a fuel derived from mixture of waste engine oil and waste canola oil
methyl esters.
ix. To investigate combustion, performance and emission characteristics of a diesel engine
with a fuel obtained from mixture of waste transformer oil and waste canola oil methyl
esters.
x. To investigate combustion, performance and emission characteristics of a diesel engine
operated with a fuel derived from waste cooking oil methyl esters.
xi. To investigate combustion, performance and emission characteristics of a diesel engine
operated with a fuel derived from mixture of waste tyre pyrolysis oil and waste rapeseed
oil methyl esters.
xii. To compare the results of prepared fuel blends with pure diesel and biodiesel fuel
standards specified by American Society for Testing and Materials (ASTM).
57
CHAPTER 2
MATERIALS AND METHODS
2.1 Equipment and Chemicals
2.1.1 Equipment
Following equipment were used during the research work:
A Diesel Engine Kirolaskar TAF-1
Exhaust Gas Analyzer (AVL Di Gas 444)
Diesel Smoke Meter (AVL 437)
FTIR Spectrometer, Spectrum Two, Perkin Elmer, USA.
Electrical Balance (AW220, Shimadzu, Japan)
Viscometer (PSL, C-4063, England/UK)
Conradson Carbon Testing Unit (SETA/England)
Acid Base Titration Assembly
Heating Oven (Gallenkamp, England)
Hot Plate with Magnetic Stirrer
Specific Gravity Bottle
Autochemistry (940/960, Orion/USA)
Hydrometer (PSL-883823/A, BS 718 England, UK)
Thermometers Calibrated (Zeal/England)
Muffle Furnace (FSE-621, Gallenkamp/England)
58
Centrifuge (TS67310, Precision/USA)
Pour Point Apparatus (SETA/England)
Viscosity Baths for 100 and 40 °C (VHC-220, Gallenkamp/England)
Flash Point Apparatus, PMCC (3211-000-00, Lauda/Herzo-USA )
Water Bath
Copper Strips Corriosion Test Unit (9011-000-00, Lauda/Herzo-USA)
Calomel Reference Electrode
Aluminium Foil
Personal Computer
Filter Cloth
Calibrated Pyrex Glassware (beakers, cylinders, separating funnels, glass funnels,
conical flasks, measuring flasks, pipettes, burettes etc).
2.1.2 Chemicals and Glassware
Analytical grade MERCK and FLUKA brands of chemicals were used. Distilled and deionized
water was used throughout the experimental work. A detailed list of the chemicals is given in
Table 2.1. In experimental process, all glasswares used were of Pyrex and E.mil brands. The
glassware was washed with nitric acid and chromate mixtures followed by distilled and
deionized water prior to use.
59
Table 2.1 List of chemicals used during the research work.
Sr. No. Chemicals Formula Manufacturer
1 Methanol CH3OH Merck
2 Potasium Hydroxide KOH Merck
3 Sodium Hydroxide NaOH Merck
4 Toluene C6H5CH3 Merck
5 Isopropyl Alcohol C3H7OH Merck
6 Acetic Acid CH3COOH Fluka
7 Sodium Sulphate Na2SO4 Merck
8 Oxalic Acid C2O4H2 .2H2O Fluka
9 Sulphuric Acid H2SO4 Merk
10 Hydrochloric Acid HCl Merck
11 n-Hexane C6H14 Merck
12 Sulfuric Acid H2SO4 Merck
13 Zinc Oxide ZnO Merck
14 Sodium Chromate Na2CrO4 Merck
15 Nitric Acid HNO3 Merck
16 Pottassium Dichromate K2Cr2O7 Merck
2.2 Samples Collection
The waste oil samples were collected from different sources as explained below:
i). The waste engine oil composite sample was collected from M/S Ashiq Motor
Workshop, Multan, Pakistan as well as the engine oil was collected from the
sump of a personal vehicle engine (Cultus Car/model 2006, Registration No.
MLJ-2083) after covering specified distances.
ii). The waste transformer oil was collected from Hydro-electric Power Station
located at Multan, Pakistan, as per standard sampling procedures.
60
iii). The light fraction of waste tyre oil was collected from a commercial tyre pyrolysis
plant M/S Gravity Mills, Muzzafar Garh, an adjacent city of Multan, Pakistan.
iv). The waste cooking oil was collected from two different restaurants on the basis of
virgin vegetable oils (canola oil and soybean oils). One waste cooking oil sample
was collected from M/S Eat ON Restaurant located at Multan, Pakistan. The
sample was known to be waste canola oil. The other waste cooking oil sample
was collected from M/S Lasani Food Restaurant, Multan, Pakistan. The waste
cooking oil description was acquired from the restaurant managers and was
known to be waste soybean oil.
v). The waste rice husk was collected from a local rice grinding mill at Multan,
Pakistan.
2.2.1 Pre-treatment
The waste oil samples mentioned in section 2.2 were dehydrated by atmospheric distillation,
filtered to remove suspended particles, dust, gum-type materials, metal particles and other
impurities.
Along with above mentioned pre-treatment, the waste transformer oil was subjected to base
catalyzed transesterification process as per procedures mentioned in the upcoming sections
so as to reduce its viscosity. The pre-treatment of waste rice husk is explained in the next
section.
2.2.2 Waste Rice Husk
Waste Rice Husk (RH) was obtained from the local Rice Mill at Multan Pakistan. The rice husk
was converted into ash by incineration and activated by further heating at 550 oC. The rice husk
ash (RHA) is an important renewable source of silica and might replace it in the process of
61
purifying biodiesel. The RHA contains approximately 95% of silica and the remainder consisting
by other inorganic components as K2O, CaO and P2O5. These inorganic impurities of RHA do
not influence the adsorption process, indicating that the adsorption of oil has a slight correlation
with inorganic components present in the RHA (Kumagai et al., 2007).
2.3 Regeneration of Waste Automotive Oil
2.3.1 Rice Husk Ash Method (Present Research)
In this method, a cheap, feasible and an environmentally friendly method has been developed for
recycling of waste automotive oils as explained hereunder.
2.3.1.1 Incineration of Rice Husk
50g of rice husk was weighed using using an electric weight balance, AW220, Shimadzu, Japan.
The rice husk ash was combusted in the crucibles using burner flame and a tripod stand at the
laboratory. The crucibles were removed from flame tripods when complete incineration of rice
husk had occurred and were allowed to cool.
Figure 2.1 Photographic view of Pakistani waste rice husk and an activated rice husk ash
.
2.3.1.2 Activation of Incinerated Rice Husk
The incinerated rice husk is also called rice husk ash (RHA). The RHA was further heated in a
high temperature muffle furnace at a temperature of 550 oC for half an hour so as to activate its
62
adsorbent sites. It is reported that activated rice husk ash at temperature of 500oC or above has
much greater adsorption power in comparison to that of un-activated one (Kumagai et al., 2007).
Pictorial view of Pakistani waste rice husk and its incinerated ash is given in Figure 2.1.
2.3.1.3 Pretreatment of Waste Engine Oil
The collected waste engine oil was left untouched for 48 hours to settle down suspended
particles and other impurities by gravity. The oil was then filtered to remove suspended particles.
2.3.1.4 Atmospheric Distillation
The filtered waste engine oil was subjected to atmospheric distillation at 110oC for 1hr to
completely dehydrate it and allowed to cool down to attain a temperature of 45-50oC.
2.3.1.5 Activated Rice Husk Ash Treatment
The temperature of the dehydrated sample was maintained at 45-50 oC. At this temperature 6g of
RHA per 100ml of the waste oil was introduced with constant stirring for 10 minutes along with
addition of 1ml each of sulfuric acid and acetic acid per 100ml of the sample (compared to
addition of 8-10% of H2SO4 in conventional acid/clay method). The solution mixture was
allowed to cool to room temperature.
2.3.1.6 Centrifugation
The mixture was then subjected to centrifugation at 1000rpm for 3hours. After centrifugation,
the sample was neutralized, clay treated and filtered. The schematic diagram showing the new
waste engine oil regeneration method as an outcome of the present study is given in Figure 2.2.
Pakistan is a rice producing country, the method of used oil regeneration would resolve its
triplicate problems, waste automotive oil disposal, waste rice husk disposal and environmental
problems arising from inappropriate disposal of these wastes.
63
Figure 2.2 Schematic diagrams showing new method of waste automotive oil regeneration.
2.3.2 Acid-Clay Treatment (Existing Method)
In this technique, waste lubricating oil was allowed to settle for 24 hours. After that the sample
was filtered then centrifuged for 30 minutes at 600 revolutions per minute. In this way, the solid
suspended phase settled at the bottom of beaker was removed and the upper liquid portion was
pretreated thermally at an atmospheric distillation at about 170 to 180 oC for 1 hour to remove
water and lighter end hydrocarbons and then cooled. 100g of pretreated oil was added with 30ml
of sulfuric acid (98% concentrated) in a 250ml beaker and heated at 45 to 50 oC for about half an
hour. The temperature greater than 50 oC would destroy some hydrocarbons by introducing
sulphonation reactions (Kumagai et al., 2007). The mixture was then allowed to cool. After 5
hours, the top layer of the oil was decanted leaving the sludge behind. The oil was then clay
treated adding 30 g of clay per 1000 ml of oil in funnel with filter cloth and neutralized. The
recycled oil was characterized for different parameters.
64
2.3.3 Distillation-Clay Treatment (Existing Method)
In this technique, atmospheric distillation was carried out at a temperature of 200 oC to remove
moisture. 200 ml of dehydrated oil was distilled in the vacuum distillation flask at a temperature
310 oC under 15 bar pressure. Distillate obtained was weighed leaving behind the residue. The
distillate was then treated with 30g of clay to improve the quality oil. The lube oil is then filtered
and clay residue is disposed of.
2.4 Fuel Blends Raw Material
2.4.1 Production of Biodiesel from Waste Canola Oil
2.4.1.1 Synthesis of Sodium Methoxide
200ml methanol was poured into a 500 ml conical flask. NaOH was weighed accurately (3.70g)
and added to the methanol. The mixture was stirred for about one hour on a hot plate untill the
sodium hydroxide had dissolved and sodium methoxide was obtained.
2.4.1.2 Transesterification Process
Pure hydrogenated vegetable oil was heated at elevated temperature (120°C). This was done to
remove the water contents. Then this hydrogenated oil was cooled to 50 °C. 1 kg of waste canola
oil was weighed and transferred to the sodium methoxide solution. The mixture was placed on a
hot magnetic stirrer and stirred at 250 rpm. During this time period, the temperature was
maintained at 55°C for about 80 minutes. The transesterification reaction is given in Figure 2.3.
65
Figure 2.3 Transesterification reaction
2.4.1.3 Separation of Biodiesel
Upon the completion of transesterification reaction, the covering of the flask was removed to
evaporate the excess methyl alcohol for about half an hour. Then the mixture was transferred to a
separating funnel and was left overnight. Two distinct liquid phases appeared inside the
separating funnel. The upper layer was of crude biodiesel and the lower layer was of crude
glycerine. The crude biodiesel layer was removed from the glycerine layer by transferring it into
a conical flask.
2.4.1.4 Purification of Biodiesel
The unreacted reagents were eliminated by washing the crude biodiesel with deionized water
(30% by volume of biodiesel) in the separating funnel. The washing procedure was repeated
three times. After that, the biodiesel was dried with Na2SO4 and followed by filtration to obtain
pure biodiesel. The flow chart of biodiesel production is given in Figure 2.4.
66
Figure 2.4 Flow Chart of biodiesel production process.
2.4.2 Production of Biodiesel from Waste Corn, Soybean and Sunflower Oil
The waste corn, soybean and sunflower oils were subjected to base catalyzed transesterification
reaction using sodium hydroxide (NaOH) as catalyst. The same procedure of biodiesel
production was followed as discussed in section 2.4.1.
CH3OH CH3OH
CH3OH removal
CH3OH removal
67
2.4.3 Transesterification of Waste Transformer Oil
The waste transformer oil was first filtered to remove suspended particles, dust, gum-type
materials, metal particles and other impurities, then subjected to a transesterification process
as per procedures mentioned in section 2.4.1 so as to reduce its viscosity. Various
transesterified waste transformer oil biodiesel blends were prepared for further treatment.
2.4.4 Catalytic Cracking of Waste Engine Oil
The waste engine oil was decanted, centrifuged and subjected to atmospheric distillation at 110
oC for 1 hour to remove moisture. The oil was then pretreated to remove heavy metal particles
gum type materials and carbon soot and filtered to remove suspended particles. The pretreated
waste oil was then subjected to catalytic cracking using cheap readily available alumina (Al2O3)
as a catalyst in a batch reactor as shown in Figure 2.5. The reaction was carried out at lower
temperature and pressure under vacuum. The batch reactor comprised an oil inlet, pressure
gauge, safety valve and a drain hole to remove residues. The reactor was coupled to a condenser.
The batch reactor was filled with pretreated waste engine oil with 50g/L of alumina catalyst.
When heat was supplied from the bottom of the reactor using a natural gas burner, rapid
chemical reaction occurred inside the reactor, hence the complex structure of the waste oil was
broken down in the form of vapours which condensed to low density and low viscosity liquid.
Condensation started at a temperature of 320 oC and continued up to 480 °C yielding 78 wt.%
liquid fuel with 6-8% uncondensed gases and 10-15% percent sludge type residue was remaining
in the reactor. Non condensed gases were flared into atmosphere. The liquid fuel produced was
named as cracked waste engine oil (CWEO) and was heated to 180 oC for one hour before
further treatment to improve its flash point. This oil was called pre-treated cracked waste engine
68
oil (PCWEO) which is blended with 60% vegetable oil methyl esters (produced from waste
cooking oil) and different proportions of petroleum diesel.
Figure 2.5 Schematic diagram of a batch reactor used for cracking of waste engine oil.
2.4.5 Waste Tyre Pyrolysis Oil.
Thermal degradation of a substance into smaller and less complex molecules in the absence of
oxygen is known as pyrolysis. The light fraction of waste tyre oil was collected from a
commercial tyre pyrolysis plant M/S Gravity Mills located at Muzzaffar Garh near Multan,
Pakistan.
In the pyrolysis process, three major products are produced, such as gas, char and pyrolytic oil.
The tyre pyrolysis oil is used to fire the boilers and high temperature furnaces to produce
69
electricity for the sustainable operation of the plant. The schematic flow diagram of the plant
setup is given in Figure-2.6.
Figure 2.6 Waste tyre oil pyrolysis process flow sheet.
After removal of steel wires and beads, the waste tyre chips are fed into the reactor unit to
decompose hydrocarbon compounds at high temperature (460–660oC) under oxygen free
atmosphere. The process makes the restructuring of rubber and converts it into vapours and
gases which pass through the separator where heavy oil is separated out from gases and the
vapours of the light oil fractions are condensed into liquid after passing through the condenser
yielding 42-46% tyre pyrolysis oil with 9-10% non condensable gases which are recycled again
and used for heating the reactor.
2.5 Investigations on a Diesel Engine with Various Fuel Blends
2.5.1 Engine Setup
A 5.5kW single-cylinder water-cooled direct-injection diesel engine has been used in this study.
The details of the engine specifications are given in Table 2.2. The engine was coupled to a
hydraulic dynamometer for the measurement of the torque. A laser sensor was used to measure
70
the engine speed. A calibrated load cell was attached with the dynamometer. An electronic
weighing scale was used to measure fuel flow rate. The emission and performance parameters
were measured as per ISO-3046 standard (ISO 1996). Exhaust gas temperature was directly
measured by using thermocouples installed at inlet and outlet pipes. The schematic diagram of
the experimental setup is shown in Figure-2.7.
Figure 2.7 Schematic diagram of experimental setup.
AVL-437 smoke meter was used to measure smoke opacity. For the measurement of carbon
monoxide (CO), hydrocarbon (HC) and nitrous oxide (NOx), an AVL 444 DI gas analyzer was
used. Before every measurement, the engine was started and warmed up to attain the steady
speed. The temperature was maintained by circulating water. The combustion, performance and
emission variables were measured at different engine loads. The output signal was collected by a
data acquisition board and sent to a PC.
The tests were repeated and mean value of three measurements was used for calculations. The
photographic view of the engine is given in Figure-2.8.
71
Table 2.2 Technical specifications of the engine used during the research work.
Particulars Details
Engine Model Kirolaskar TAF-1 Maximum power (kW) 5.5 Type Water-cooled, four stroke Rated speed (rpm) 1600 Number of cylinders 1 Bore 87.5mm Stroke 110mm Compression ratio 17.5:1 Combustion Direct injection (DI) and
naturally aspirated Injection timing 23° before TDC
Exhaust gas
analyzer
Model AVL Di Gas 444 HC (ppm)
Range 0 to 30,000 Accuracy ±4% Data resolution 1 CO (%)
Range 0 to 15 Accuracy ±0.06 Data resolution 0.001 NOx (ppm)
Range 0 to 5,000 Accuracy ±2% Data resolution 1 Smoke meter AVL 437
Range 0-100% Accuracy ±1% Alarming signal tempertaure 70oC Light Source Halgen Lamp, 12V
All the tests were conducted by starting the engine with diesel only. After the engine was
warmed up, it was switched to the diesel operation. At the end of the test, the fuel was switched
back to diesel, and the engine was kept running for a while, before shut-down, to flush the diesel
from the fuel line and the injection system. All the tests were conducted at the rated speed of
1500 rpm. All readings were taken only after the engine attained stable operation. The gas
analyzers were switched on before starting the experiments to stabilize them before starting the
measurements. All the instruments were periodically calibrated.
72
Figure 2.8 Photographic view of the diesel engine
The injector opening pressure and injection timing were kept constant at the rated value during
this phase of the study. The engine output was varied from no load to full load in steps of 25%,
50%, 75% and 100% in the normal operation of the engine. At each load the fuel flow rate, air
flow rate, exhaust gas temperature, emissions of carbon monoxide, hydrocarbon and oxides of
nitrogen, and smoke readings were recorded.
2.5.1.1 Exhaust Gas Measurements
An AVL DiGas444 exhaust gas analyzer was used to measure the pollutant emissions like HC,
CO and NO emissions from the engine exhaust. NO was measured with a photochemical sensor.
The HC and CO emissions were measured with the help of sensors working on non-dispersive
infrared (NDIR) principle. A photographic view of the exhaust gas analyzer is shown in Fig. 2.9.
73
The detailed specifications of the AVL DiGas444 analyzer are presented in Table 2.2 present in
section 2.5.1 above. In order to ensure the accuracy of measurement, the recommended periodic
calibration of the gas analyzer was carried out. The calibration procedure involved injection of
calibration gases of known concentration and validating the response. To correct for variations in
electronic response due to interferences, drifts and temperature effects, instrument outputs were
adjusted to the known inputs. Thus the accuracy of the analyzer was assured and an accurate
response to the sampled gas was achieved after calibration.
Figure 2.9 Photographic view of the exhaust gas analyzer.
The smoke density of the exhaust emission was measured with the help of an AVL 437 diesel
smoke meter. This measuring instrument consists of a sampling probe that sucks a specific
quantity of exhaust sample through a white filter paper fitted in the smoke meter. The reflectivity
of the filter paper was measured by the smoke meter. This consisted of a light source which and
an annular photo detector illuminate the fitter paper to measure the reflected light. Before every
sample, it was ensured that the exhaust from the previous measurement was completely driven
off from the tube and pump. A photographic view of the diesel smoke meter is shown in Fig.
74
2.10. The detailed specifications of the diesel smoke meter are presented in Table 2.2 section
2.5.1 above. Periodical calibration of the smoke meter was carried out. The method of calibrating
the smoke meter involves warming the heating elements up to 70oC. In order to avoid
measurement error, the heating was designed to prevent the temperature falling below dew point.
Fresh air was allowed to enter the measurement chamber which is drawn through the fitter paper.
The zero point for calibration was set and measurement was carried out. The probe of the
exhaust gas analyzer was inserted at end of the exhaust pipe during measurement of emissions.
Once the engine reached stable operation, the probe was inserted into the exhaust pipe and the
measurements were taken.
Figure 2.10 Photographic view of the smoke meter.
2.5.2 Fuel Blends Derived from Waste Oils
Blending is the simplest method of using a high viscous fuel as an alternative fuel in a CI engine
by mixing it with a diesel fuel or low viscous fuel (Chauhan et al. 2010). Various blends of
pretreated waste engine oil, waste transformer oil, waste tyre pyrolysis oil and waste cooking oil
were prepared with diesel in different proportions and experimental investigations were carried
75
out. The blends were mechanically agitated to get the homogeneous stable mixtures. The
photographic view of the mechanical agitator is given in Figure 2.11.
Figure 2.11 Photographic view of the blends agitator.
2.5.2.1 Waste Engine Oil Biodiesel Blends
The waste engine oil-biodiesel blend was prepared from a 40:60 mixture of pretreated cracked
waste engine oil (PCWEO) as discussed in section 2.4.4 and waste canola oil methyl esters
(WCOME) and was named as composite fuel blend (CFB). The CFB was further mixed with
petroleum diesel in different proportions and various blends like CFB15, CFB25, CFB35,
CFB45 and CFB55 were prepared as shown in Table-2.3.
76
Table 2.3 CFB and its blends composition
2.5.2.2 Waste Transformer Oil-Biodiesel Blends
The waste transformer oil-biodiesel blend was prepared from a 50:50 mixture of transesterified
waste transformer oil (TWTO) discussed in section 2.4.3 and waste canola oil methyl esters
(WCOME) discussed in section 2.4.1. The fuel mixture was named as biodiesel like fuel (BLF).
The BLF was further mixed with petroleum diesel in different concentrations and various blends
like BLF15, BLF20 and BLF25 were prepared as shown in Table 2.4.
Table 2.4 BLF and its blends Composition
2.5.2.3 Waste Tyre Pyrolysis Oil-Biodiesel Blends
The waste engine oil-biodiesel blend was prepared from a 30:70 mixture of waste tyre pyrolysis
liquid discussed in 2.4.5 and waste soybean oil methyl esters discussed in 2.4.2.
Sr.
No. Fuel Type
CFB Description CFB-Diesel blends
Description
PCWEO
Volume
WCOME
Volume CFB Volume
Diesel
Volume
1 Diesel (CFB0) - - 0ml 1000ml
2 CFB15 400ml 600ml 150ml 850ml
3 CFB25 400ml 600ml 250ml 750ml
4 CFB35 400ml 600ml 350ml 650ml
5 CFB45 400ml 600ml 450ml 550ml
6 CFB55 400ml 600ml 550ml 450ml
7 CFB100 400ml 600ml 1000ml 0ml
Sr.
No. Fuel Type
BLF Composition BLF-Diesel blends
Description
TWTO
Volume
WCOME
Volume BLF Volume
Diesel
Volume
1 Diesel (BLF0) - - 0ml 1000ml
2 BLF15 500ml 500ml 150ml 850ml
3 BLF20 500ml 500ml 200ml 800ml
4 BLF25 500ml 500ml 250ml 750ml
5 BLF100 500ml 500ml 1000ml 0ml
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The blend was named as waste oil fuel mixture (FMWO). The FMWO was further mixed with
petroleum diesel in different concentrations and various blends were prepared like FMWO10,
FMWO20, FMWO30, FMWO40 and FMWO50 as shown in Table 2.5.
Table 2.5 Composition of FMWO and its blends
2.5.2.4 Waste Cooking Oil Biodiesel-Diesel Blends
The waste cooking oil biodiesel-diesel blends was prepared from a mixture of waste canola oil
methyl ester and petroleum diesel in different proportions like B20 (biodiesel 20% and
petroleum diesel 80%), B15 (biodiesel 15% and petroleum diesel 85%) and B10 (Biodiesel 10%
and petroleum diesel 90%) as shown in Table 2.6.
Table 2.6 Petroleum Diesel and biodiesel blends Composition
Sr. No Description Petroleum Diesel
(Volume)
Biodiesel
(Volume)
1 B0 1000ml 0ml
2 B10 900ml 100ml
3 B15 850ml 150ml
4 B20 800ml 200ml
5 B100 0ml 1000ml
Sr.
No. Fuel Type
FMWO Description FMWO-Diesel blends
Description
FMWO
Volume
WSOME
Volume
FMWO
Volume
Diesel
Volume
1 Diesel (FMWO0) - - 0ml 1000ml
2 FMWO10 300ml 700ml 100ml 900ml
3 FMWO20 300ml 700ml 200ml 800ml
4 FMWO30 300ml 700ml 300ml 700ml
5 FMWO40 300ml 700ml 400ml 600ml
6 FMWO50 300ml 700ml 500ml 500ml
7 FMWO100 300ml 700ml 1000ml 0ml
78
All the waste oil fuel-biodiesel blends discussed in section 2.5.2.1 to section 2.5.2.4 were
subjected to fuel properties analysis, FTIR analysis, diesel engine performance (BSFC, BTE,
EGT analysis) and emission characteristics like CO, HC, NOx and smoke density as discussed in
chapter 3. The pictorial view of the oil samples is given in Figure 2.12.
Figure 2.12 Photographic view of diesel, waste canola oil biodiesel, waste soybean oil biodiesel, waste
transformer oil methyl ester, waste engine oil and waste tyre pyrolysis oil from left to right (1-6)
correspondingly.
2.6 Fuel Properties
The Pakistani waste oils mentioned above and their biodiesel-diesel blends were characterized
for fuel properties using following standard methods.
2.6.1 Kinematic Viscosity
The kinematic viscosity of waste oils and their fuel blends was determined by using standard test
method ASTM D-445. During the test method, constant volume of the oil was allowed to run
under gravity through the capillary tube of the calibrated viscometer at given temperature and the
time of flow was measured accurately by calculation. The kinematic viscosity was calculated by
multiplying the calibration constant of the viscometer by the time of flow of oil sample through
79
the viscometer. All of the oil samples were passed through this standard test method and their
accurate values were measured in centistokes (cSt) at a temperature of 40°C.
Figure 2.13 Photographic view of viscosity baths
2.6.2 Density or Specific Gravity
The standard test method used for determination of density or specific gravity of waste oils and
their biodiesel fuel blends was ASTM D 1298. This test method covered the laboratory
measurement of density, relative density and specific gravity by using specific glass hydrometer.
For the determination of density of fuel blends, the samples from the deep freeze were heated up
to the temperature of 15°C and then poured to a cylinder around the equivalent temperature. The
hydrometer cylinder and all its contents were also put in a water bath to obtain a steady
temperature. The hydrometer was then immersed into the oil samples and permitted to settle.
When the temperature reached equilibrium, the scale on the hydrometer was checked and the
final temperature of the oil samples was noted. Photographic view of hydrometer is given in
Figure 2.14.
80
Figure 2.14 Photographic view of Hydrometer.
2.6.3 Calorific Value
Standard test method (ASTM D 240-17) was used to determine the calorific value of waste oils
and their fuel blends. The calorific value (CV) as determined in an oxygen bomb calorimeter was
measured by a substitution procedure in which the heat obtained from the sample was compared
with the heat obtained from combustion of a similar amount of benzoic acid whose calorific
value is known. These measurements are obtained by burning a representative sample in a high
pressure oxygen atmosphere within a metal pressure vessel – called a bomb. The energy released
by this combustion is absorbed within the calorimeter and the resulting temperature change
within the absorbing medium is noted. The calorific value of the samples was then calculated by
multiplying the temperature rise in the calorimeter by a previously determined energy equivalent
determined from previous tests with a standardizing material. Following apparatus were
necessary for CV analysis:
81
Oil sample (weighed)
Oxygen bomb calorimeter
Fuse wire
Thermometer
1.2 litres of water
Supply of oxygen
Power source
Stop watch
The calorific value was calculated by using following equation:
H = (tW - e1 - e2 - e3)/m (1)
H = heat of combustion of the sample in calories per gram
t = net corrected temperature rise in degrees C or F
W = energy equivalent of the calorimeter in calories per degree C or F.
e1 = correction in calories for heat of formation of nitric acid (HNO3) = cl if 0.0725N alkali was
used for the titration.
e2 = correction in calories for heat of formation of sulfuric acid (H2SO4) = (14) (c2) (m)
e3 = correction in calories for heat of combustion of fuse wire = (2.3) (c3) when using Parr
45C10 nickel-chromium fuse wire, or = (2.7) (c3) when using No. 34 B. & S. gage iron
fuse wire.
m = mass of the sample in grams.
The photographic view of bomb calorimeter is given in Figure 2.15.
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Figure 2.15 Photographic view of bomb calorimeter
.
2.6.4 Flash Point
The flash point (FP in oC) of waste oil and their biodiesel blends was determined by using an
international standard test method ASTM D 93. In this method, a Pensky-Martens closed-cup
tester was used. To determine the FP of waste oils and their derivative blends, the samples were
first heated at a moderately slow and steady rate with frequent stirring. A very small flame was
allowed to move into the cup at regular time intervals. FP was noted by observing the minimum
possible temperature at which test flame caused the vapor over the surface of biodiesel to ignite.
Photographic view of flash point apparatus is given in Figure 2.16.
83
Figure 2.16 Photographic view of flash point apparatus.
2.6.5 Acid Value
The acid value of waste oil and their biodiesel blends was determined by using an international
standard test method ASTM D-664. This method covered the procedure to determine the acidic
constituents in petroleum, biodiesel and other lubricants. To determine acid number, firstly, a
mixture of toluene and isopropyl alcohol was prepared containing little volume of solvent. Then
the fuel blend samples were dissolved in this mixture for a definite time. This mixture was then
titrated potentiometrically with alcoholic KOH using a calomel reference electrode and internally
shielded glass indicating electrode. The readings of potentiometer were plotted against the
relevant volumes of titrating solution. The definite inflections appeared on the resultant curve
84
which indicate the end points of this titration. A stage was reached where no well-defined
inflections appeared on the curve. At that stage the end points were measured at meter readings
parallel to those originating from newly prepared acidic and basic buffer solutions of non-
aqueous nature. Photographic view of potentiometer for total acid number is given in Figure
2.17.
Figure 2.17 Photographic view of potentiometer for total acid number.
2.6.6 Pour Point
The pour point (PP) oC of waste oil and their biodiesel blends was determined by using an
international standard test method ASTM D-97. This test was intended for use on any petroleum
oil and vegetable oil based fuel. To find the pour point, waste oil and their biodiesel blends were
85
firstly preheated for a very short time. After this preliminary heating the samples were
refrigerated at a moderate rate and checked at regular time intervals of 3°C for pour character.
The degree upon which the flow of the oil samples ceased to exist is known as the pour point.
Figure 2.18 Photographic views of pour point apparatus.
2.6.7 Water Contents
The water or moisture content of waste oil and their biodiesel blends was determined by using an
international standard test method ASTM 95. This standard method covered the exact estimation
of water contents in petroleum fractions and biodiesel by the distillation process. The biodiesel
was moderately heated along with reflux condensation by using water immiscible solvent, which
was co-distilled with water in the sample of biodiesel. The water and solvent started to separate
from each other in a specific trap after condensation. The condensed solvent returned to the glass
still while the water settled in the graduated part of the trap.
86
2.6.8 Ash Contents
This standard was issued under the designation of ASTM D 482. This method covered the
determination of the ash contents in waste oils and their biodiesel blends. During the process, the
waste oils and their biodiesel blends were ignited and burned at high temperature in muffle
furnace at a temperature of 650 to 700 oC. After some time the burnt sample containing ash
residue was removed from the furnace, cooled and weighed. Photographic view of muffle
furnace is given in Figure 2.19.
Figure 2.19 Photographic view of high temperature furnace for ash contents test.
2.6.9 Conradson Carbon Residue
The conradson carbon residue of waste oil and their biodiesel blends was determined by using an
international standard test method ASTM 189. This standard method covered the complete
determination of the quantity of carbonaceous deposit remaining after the evaporation and
87
pyrolysis of waste oil-biodiesel fuel blends. To determine the carbon residue, the pre-weighed
amount of biodiesel was poured in a porcelein crucible. After the destructive distillation of
biodiesel, residue obtained was allowed to undergo cracking for the duration of a fixed period of
severe heating. A desiccator was used to cool the residue obtained in the crucible after the
cracking. The residue remaining was weighed and measured as a percentage (%) of the waste oil-
biodiesel fuel blend samples.
2.6.10 Distillation
ASTM D-86 standard was used for distillation analysis. This test method covered the
atmospheric distillation of petroleum products using a laboratory batch distillation unit to
determine the boiling range characteristics of the fuel blends as discussed in above sections.
A 100mL specimen of the sample was distilled under prescribed conditions for the group in
which the sample falls. The distillation was performed in a laboratory batch distillation unit at
ambient pressure under conditions that are designed to provide approximately one theoretical
plate fractionation as shown in Figure 2.20. Systematic observations of temperature readings and
volumes of condensate were made, depending on the needs of the user of the data. The volume
of the residue and the losses were also recorded.
88
Figure 2.20 Photographic view of distillation unit.
2.6.11 Sulphur Contents
Sulphur contents were analyzed using standard method (ASTM D-1552). This test method
covers the determination of sulfur in petroleum products, including lubricating oils using quartz
tube. The test method is applicable to any petroleum product sufficiently low in volatility that it
can be weighed accurately in an open sample boat and containing at least 0.06 % sulfur.
2.6.12 Cetane Index
The cetane index of waste oil and their biodiesel blends was determined by using international
standard test methods ASTM ASTM D-613 and ASTM D-976. The specific formula was used to
measure the cetane index of waste oil fuel blends as well as well as petroleum diesel. As per
ASTM methods mentioned above, the cetane index was calculated by using following equation.
Calculated cetane index = -420.34 + 0.016G2 + 0.192 G log M + 65.01(log M)2– 0.0001809M2
where G is gravity, M is mid-boiling temperature in °F , D is density at 15°C (g/ml), B is mid-
boiling temperature in °C.
89
2.7 Infrared Spectroscopy
2.7.1 Background
Infrared radiation is electromagnetic radiation with a wavelength between 0.7 and 100 μm.
This range is further divided in the near-IR (NIR) range (wavelength 0.7 μm to roughly 4 μm),
mid-IR (wavelength 4 μm to roughly 20 μm), and far-IR (wavelength 20 μm to 100 μm). For
analytical applications, mostly NIR and mid-IR spectroscopy are used. In IR spectroscopy, IR
radiation is directed through the sample to be analyzed and the intensity of the transmitted
radiation is measured as a function of wavelength. When the wavelength of the light matches the
energy difference between the ground and excited vibrational state of a molecule in the sample
the radiation will be absorbed. The absorption of radiation is given by the Beer-Lambert law,
stating that the absorbance A is given by the equation
A(ν)=-log[I(v)/I0(ν)]=c×l×α(ν) (2)
where c is the concentration, I(v) is the sample intensity, I0(ν) is the intensity of standard source,
l is the sample path length, α(v) is a molecule specific constant.
From this equation we can conclude that A increases linearly with both sample concentration and
the sample path length. Generally, a molecule has multiple vibrational modes resulting in
absorption of IR light. This implies that α(v) depends on wavelength. By measuring the
absorption at a constant path length over a broad spectral range in the IR region the
concentrations of many different substances can be determined simultaneously.
In mid-IR spectroscopy the fundamental molecular vibrations, which are typically narrow and
substance specific signals, are excited. Moreover, a substance exhibits different vibrational
modes at different frequencies helping to identify individual compounds even if partial overlap
of bands occurs.
90
2.7.2 FTIR Spectrometer
Nowadays the instrument of choice to measure complete IR spectra is the Fourier Transform
Infra Red (FTIR) spectrometer. FTIR instruments mostly use an interferometer for the
measurement of the sample spectrum. It splits the light emitted from a source into two equal
parts by a beam splitter typically made of ZnSe. This allows the measurement of spectra having a
resolution of 1.0 cm-1 and range of 4000-500 cm-1 covering all relevant signals for fuel and
lubricant analysis. The two light beams are directed onto a mirror reflecting the IR light back
towards the beam splitter where they recombine and are directed towards the detector. If both
mirrors are positioned at the same distance from the beam splitter no phase shift between the two
parts is introduced. During a measurement one of the two mirrors moves away from the beam
splitter at a constant speed. When the displacement of the mirror equals one quarter of the
wavelength of the light, the combined beams are out of phase resulting in destructive
interference. In this case no light hits the detector. As the mirror is scanned, the light intensity
measured by the detector will show a modulation. The intensity measured by the detector as a
function of the mirror displacement is called an interferogram. For a monochromatic source, the
interferogram will be a sine wave. For polychromatic light, which is emitted by typical IR light
sources exhibiting a broad wavelength distribution, the interferogram will be the sum of sine
waves of all frequencies present in the source. A Fourier transform of the interferogram gives the
spectrum. By referencing the spectrum of the sample I(v) to that of the source I0(v), the (sample)
absorption spectrum is obtained according to equation 2. The absorption spectrum will show a
set of bands corresponding to frequencies where the sample absorbed light.
91
2.7.3 FTIR Analysis
All the waste oils (waste engine oil, waste transformer oil, waste tyre pyrolysis oil and waste
cooking oil) and their biodiesel-diesel blends were analyzed using FTIR spectrometer,
(SpectrumTwo, Perkin Elmer, USA, having a resolution of 1.0 cm-1). The IR spectra of the
samples were recorded within the range 4000-500 cm-1. ASTM standard E-2412 was used for
FTIR analysis. The FTIR spectra were used for the comparison of different absorption frequency
peaks of chemical groups to distinguish the nature of the chemical compounds present the waste
oils. Pictorial view of the FTIR spectrometer is given in Figure 2.21.
Figure 2.21 Photographic view of FT-IR Spectrometer and data acquisition system.
FT-IR
Spectrometer
ASTM E 2412
Data Acquisition
System
92
Chapter 3
RESULTS AND DISCUSSION
3.1 General
This chapter presents i) a detailed discussion on the results obtained from a developed method of
Pakistani waste automotive oil regeneration and its comparison with existing conventional waste
engine oil recycling methods; ii) physicochemical characterization and FT-IR analysis of
biodiesel produced from various types of waste cooking oils; iii) investigations on various
Pakistani waste oils like waste engine oil, waste transformer oil, waste tyre pyrolysis oil, waste
cooking oil and their biodiesel blends; and then iv) application of above noted waste oil-
biodiesel-diesel blends in a 5.5kW, single-cylinder four-stroke diesel engine in respect of
combustion, performance and emission characteristics.
3.2 Waste Automotive Oil
The properties of waste oil samples were determined before blending and recycling process. All
the waste oil samples were characterized and the results have been tabulated in Table 3.1. The
composite blend of waste oil samples was recycled and the regenerated oil was characterized for
physicochemical properties as shown in Tables 3.2, 3.3, 3.4 and 3.5.
Table 3.1 Waste Automotive Oil Characteristics
Description Units WAO-1 WAO-2 WAO-3 WAO-B
Water Content Vol.% 1.5 2.4 1.8 2.2
Specific gravity at 60 oF - 0.9128 0.927 0.9108 0.9196
Flash Point (Open Cup) oC 175 168 179 174
Viscosity at 40oC cSt 45.24 39.71 48.17 44.69
Ash Content Wt.% 2.74 1.95 2.16 2.38
Colour (visual) - Black Black Black Black
.
Table 3.1 shows the characteristics of three different waste oil samples (coded as WAO-1,
WAO-2, WAO-3 and their blend (coded as WAO-B). WAO-1, WAO-2, WAO-3 and WAO-B
stand for waste automotive oil one, two, three and waste automotive oil composite blend,
93
respectively. Water contents of the waste oil samples varied from 1.5 to 2.4 volume percent.
Specific gravity varied from 0.9128 to 0.9270. Flash point and viscosity varied from 168 to 179
degree centigrade and 39.71 to 48.17 centistokes. Above variations can be due to the different
collection sources of the samples. Ash contents varied from 1.95 to 2.74 percent. This difference
might be due to the variations in additive percentage which was initially added in their respective
base stocks. Visual colour of all the waste automotive oil samples was black.
3.3 Recycling of Waste Automotive Oil Using Rice Husk Ash
The results of different parameters of base oil regenerated from waste automotive oils using rice
husk ash are tabulated in Tables 3.2 and 3.3.
For regenerated oil samples specific gravity varies from 0.8927 to 0.9082 in Table 3.4 and
0.8875 to 0.9031 in Table 3.5. As reflected in Table 3.5 sample RA6 has a specific gravity of
0.8875, closer to the virgin oil. That is to say that acetic acid improves the specific gravity
compared to sulfuric acid. Table 3.4 shows slight improvement in the specific gravity because
sulfuric acid itself is very dense (Sp. gr. of 98% H2SO4 is 1.83).
Viscosity decreases with increase in the temperature of the automotive oil while it increases with
decrease in temperature as shown in (Tables 3.4 and 3.5). Kinematic viscosities were in the
ranges 64.17 to 65.10 and 63.01 to 64.00 respectively. The regenerated automotive oil RS6 in
Table 3.4 with viscosity 65.10 shows better improvement and is closer to the virgin oil viscosity.
Flash point (FP) demonstrates the contamination of the engine oil. Low flash point of engine oil
is a threat that the oil has become contaminated with the volatile products like gasoline or diesel.
FP is directly related with the molecular mass of the oil. Tables 3.2 and 3.3 show that flash point
of different regenerated samples varies from 173 to 188 oC and 168 to 174 oC, respectively.
Sulfuric acid better improves flash point due to good removal of lower fractions.
94
Table 3.2 Regenerated Oil Characteristics (RHA + 1% H2SO4).
Description Unit A* RS1 RS2 RS3 RS4 RS5 RS6 RS7 RS8
Sp. Gravity - 0.876 0.908 0.902 0.898 0.896 0.894 0.892 0.893 0.893
Flash Point oC 201 175 173 178 174 180 188 184 182
Pour Point oC -9 -3 -3 -3 -3 -3 -3 -3 -3
Kin. Viscosity
at 40 oC
cSt 68.22 64.17 64.23 64.29 64.31 64.85 65.17 64.24 64.68
Ash Contents Wt.% 0.005 0.28 0.17 0.10 0.08 0.05 0.04 0.05 0.05
Yield Vol. % - 48.2 51 53.4 54 56.2 58.6 58.4 58.3
The regenerated oil samples using slight amounts of sulfuric acid given in Table 3.2 have pour
point -3 oC and oil samples re-refined using a small amount of acetic acid as given in Table 3.3
have pour point -6 oC which is closer to the virgin oil. This means that acetic acid improves the
pour point.
Table 3.3 Regenerated Oil Characteristics (RHA + 1% CH3COOH).
Ash contents indicate dirt and metallic residues at the bottom of the oil samples after combustion
followed by burning at 650 oC. For re-refined oils, improvement in the ash contents in Table 3.3
and Table 3.2 has been noted as 2.38 to 0.04 percent and 2.38 to 0.07, respectively. This
improvement in the ash contents is the significant indication for better processing.
Description Unit A* RA1 RA2 RA3 RA4 RA5 RA6 RA7 RA8
Sp. Gravity - 0.876 0.908 0.902 0.898 0.896 0.894 0.892 0.893 0.892
Flash Point oC 201 172 170 168 170 173 174 171 169
Pour Point oC -9 -6 -6 -6 -6 -6 -6 -6 -6
Kin. Viscosity
at 40 oC
cSt 68.22 64.17 64.23 64.29 64.31 64.85 65.17 64.24 64.68
Ash Contents Wt.% 0.005 0.28 0.17 0.10 0.08 0.05 0.04 0.05 0.05
Yield
Vol.
% - 51.2 53.4 54.3 55.2 56.8 57.5 57.8 57.6
95
3.4 Comparison with Acid/Clay and Distillation Clay Methods.
Re-refining of Pakistani local crankcase waste oil was investigated. Double Falcon SAE 20W/50
grade oil was being used in a personal Cultus Car (Suzuki/2010 model) for 3000 kilometers. The
sample was collected during the oil change of the vehicle. The fresh oil was tested before
inserting it into the sump of the vehicle engine. The parameters of used oil and fresh oil samples
were evaluated according to ASTM standard test methods and tabulated in Table 3.4.
The characteristics of the oil re-refined by acid/clay, distillation clay and rice husk ash clay are
given in Table 3.5. The regenerated oil was analyzed for density at 15 oC (or specific gravity at
60/60 oF), flash point oC, copper strip corrosion, pour point oC, water contents, total acid number,
API gravity, viscosity index, kinematic viscosity at 100 and 40 oC.
After dehydration (removal of water from waste engine oil at atmospheric distillation) the values
of the used oil were changed from 71 to 102, 0.9241 to 0.8933, 180 to 187 oC, 1.8 to 0.05 Vol.%,
-33 to -30 oC, 3.4 to 1.32mgKOH/g for viscosity index (VI), specific gravity, flash point, water
contents, pour point and total acid number, respectively, as given in Tables 3.4 and 3.5. For
simplicity the results have been presented graphically in Figures 3.1 and 3.2 respectively.
As per descriptions of Tables 3.4 & 3.5, the specific gravity of re-refined oil decreased from
0.9241 to 0.8621 for acid/clay, 0.9241 to 0.8648 for distillation/clay and 0.9241 to 0.8636 for
newly developed rice husk ash/clay technique.
96
Table 3.4 Characteristics of the oil re-refined with different techniques.
Sr.
No. Characteristics Units
Samples
Used Oil Fresh Oil
(SAE 20W/50)
1 KV @ 100oC Cst 11.4 18.30
2 KV @ 40oC Cst 125.13 167.11
3 Viscosity Index - 71 122
4 Specific Gravity @60/60 oF - 0.9241 0.8786
5 Flash Point oC oC 180 244
6 Water Content Vol% 1.8 0.2
7 Pour Point oC oC -33 -21
8 Total Acid No. mgKOH/g 3.4 0.12
Figure 3.1 Comparison of Kinematic Viscosity at 100 & 40 oC, Viscosity Index and Flash Point
Kin. Viscosity @ 40 oC Kin. Viscosity @ 100 oC
97
Table 3.5 Characteristics of the oil re-refined with different techniques.
Sr.
No. Characteristics Unit
Techniques
Dehydration Acid/Clay Distillation
/Clay
Rice Husk
Ash/Clay
1 KV @ 100oC Cst 13.93 14.56 13.50 13.58
2 KV @ 40oC Cst 132.4 135.60 118.02 116.17
3 Viscosity Index - 102 107 111 114
4 Specific Gravity
@60/60 oF - 0.8933 0.8621 0.8648 0.8636
5 Flash Point oC oC 187 192 214 216
6 Water Contents Vol% 0.05 0.4 0.1 0.2
7 Pour Point oC oC -30 -9 -12 -15
8 Total Acid No. mgKOH/g 1.32 0.38 0.46 0.57
9 Yield Vol% - 78 80 82
Figure 3.2 Comparison of specific gravity, total acid number mgKOH/g and water contents (Vol.%) of the
engine oil re-refined with different techniques.
98
Specific gravity of re-refined oil was closer to the specific gravity, 0.8786, of the fresh
lubricating oil. The decrease of specific gravity of lube oil confirms the removal of heavier
contaminants (Udonne, 2011). A special function of specific gravity is the API gravity which
improved from 21.62 to 32.34.
Kinematic Viscosity at 100 oC was increased from 11.40 to 14.56 cSt, 11.40 to 13.50 cSt and
11.40 to 13.58 cSt for acid/clay, distillation/clay and rice husk clay, respectively. Viscosity Index
(VI) can be calculated with help of kinematic viscosity at 100 oC and kinematic viscosity at 40
oC from the Viscosity Index standard table. Viscosity Index increased from 71 to 107 for
acid/clay, 71 to 111 for distillation/clay and 71 to 114 for the newly developed rice husk ash/clay
technique. Results show that the viscosity of used oil was lost due to contamination and the same
was restored by re-refining the oil. The highest viscosity is given by the rice husk ash/clay
technique as shown in Table 3.5. Actual viscosity index of fresh oil was recorded as 122 before
use which was decreased to 71 after use. Any decrease in the original viscosity of the lube oil is
due to the contamination (Scapin, 2007). Results indicate that the re-refining of the waste
lubricating oil has restored most of the viscosity after removing the contaminants.
The observed flash points of the oil are 180, 244, 192, 214, and 216 oC for waste oil, fresh oil,
for acid/clay, for distillation/clay and for rice husk ash/clay techniques respectively. Decreased
value of flash point in waste lube oil is due to the presence of light ends of oil. The lube oil
undergoes thermal degradation during use inside the engine and longer chain hydrocarbons are
converted into shorter chain hydrocarbons giving rise to the lighter fractions (Rincon, 2005).
Water contents present in the lube oil in service depends upon the usage of the automobiles.
Traces of water in the lubricating oil are unavoidable that are coming from the sources like
engine cooling system leaks, oil cooler leakage and an atmospheric condensation in all types of
99
machinery (Eman et al., 2013). Water contents were observed 1.8 Vol. % in used oil. In re-
refined oil water contents decreased from 1.8 to 0.4 Vol. %, 1.8 to 0.1 Vol. % and 1.8 to 0.2
Vol.% in acid/clay, distillation/clay and rice husk ash/clay methods, respectively.
Pour Point changed from -33 to -9 oC in acid/clay, -33 to -12 oC in distillation/clay, -33 to -15 oC
in rice husk ash/clay technique. Pour Point widely varies depending upon the base oil, the source
of lube oil and the method of re-refining (Udonne, 2011). Total Acid Number is also reduced
significantly, from 3.4 to 0.38 mg KOH/g, 3.4 to 0.46 mg KOH/g and 3.4 to 0.57mgKOH/g for
acid/clay, distillation/clay and rice husk ash/clay techniques, respectively; this indicates the
reduction of inorganic and organic acids, phenolic compounds, esters, resins and lactones (Eman
et al., 2013).
3.5 Preparation of Biodiesel from Waste Cooking Oil
Biodiesel was prepared from various waste cooking oil resources like waste sunflower oil, waste
corn oil, waste soybean oil and waste canola oil through a base catalyzed trans-esterification
reaction. Physicochemical characteristics of various waste cooking oil methyl esters (biodiesel)
were carried out and compared with ASTM D-6751 and EN 14214 standard methods as shown
in Tables 3.6 and 3.7. It was observed that soyabean and canola oil methyl esters (biodiesels)
have shown optimum results as compared to waste sunflower oil methyl ester and waste corn oil
methyl esters.
Fourier transform infrared spectroscopy has become one of the major analytical tools due to its
quality, screening, quickness, and cost of the analysis. The biodiesels prepared from waste
cooking oils nearly identified and characterized in spectral range of 4000-500 cm-1.
100
Table 3.6 Physico-chemical properties of waste cooking oil methyl esters (biodiesel).
Fuel Type Specific
Gravity
Kinematic
Viscosity
@ 40 oC,
(cSt)
Flash
Point
(PMCC)
(oC)
Pour
Point
(oC)
Carbon
Residue
wt.%
Acid
Value
mgKOH/g
Water
Content
mgL-1
Ash
Content
mgL-1
ME-WSFO 881 4.42 132 -12 0..23 0.18 445 0.02
ME-WCAO 883 4.23 128 -9 0.21 0.19 450 0.02
ME-WSBO 882 4.17 152 -6 0.19 0.16 418 0.01
ME-WCRO 883 4.14 146 -6 0.20 0.10 410 0.01
Specifications
ASTM D6751 - 1.9-6.0 > 130 - - < 0.80 < 500 < 0.02
EN 14214 860-900 3.5-5.0 > 120 - < 0.30 < 0.50 < 500 < 0.02
Table 3.7 Comparison of calorific value, cetane number and distillation of waste cooking oil methyl esters
with that of diesel.
Sr.
No. Description Units
ASTM
Method ME-WSFO ME-WCRO ME-WSBO ME-WCAO
Diesel
1 Calorific value MJ/Kg D-240-
17 36.88 36.95 37.06 37.09 42.82
2 Cetane Index - D-976 46.5 46 47.0 47.5 54.5
3 Sulfur Contents mgL-1 D-1552 245 236 180 150 430
4 Distillation
IBP
oC D-86
306 294 283 278 175
10% 328 312 294 290 210
50% 342 321 316 308 278
90% 361 359 358 356 344
FBP 406 405 405 403 388
Graphical presentations of calorific value, cetane index and sulfur contents are given in Figure
3.3. However, Figure 3.4 shows the distillation oC, of various methyl esters. It was observed that
101
ME-WSBO and ME-CAO have shown closer values of calorific values, cetane index, sulfur
contents and distillation to those of petroleum diesel.
Figure 3.3 Graphical presentation of calorific value, cetane index and sulfur contents of different waste oil
biodiesel and petroleum diesel.
Figure 3.4 Graphical presentation of distillation of different waste oil biodiesel and petroleum diesel samples.
102
3.5 FTIR Analysis
The IR spectra were taken for waste cooking oils and their biodiesels. The spectral values of
waste frying oils and their biodiesels were similar since all the samples contained almost the
same chemical groups. However, some differences were observed which are discussed
hereunder.
The position of the –CO group band in FTIR is very sensitive to substitution effects and to the
structure of the molecule (Pasto et al., 1992). The methoxy-carbonyl group in biodiesel indicates
a different band position of the –COOR vibration when compared to the carbonyl group, -CO in
waste cooking oils. All the esters have two strong absorption bands arising from methoxy
carbonyl and C-O stretching (Silverstein and Webster, 1998). All the obtained results as
discussed below were according to the literature data.
The most important band appeared at 1195 cm-1 which indicates the initial formation of methoxy
(O-CH3) group and other is methyl ester (COO-CH3) peak at 1435 cm-1 in FTIR spectra of
methyl esters of waste cooking oil (biodiesel) as shown in Tables 3.5-3.12 which confirm the
formation of biodiesel. Also the strong band of the methoxy carbonyl group in biodiesel was
observed at different positions as compared to those of waste cooking oils.
Figures 3.5 and 3.6 indicate that in the waste sunflower oil, the absorption frequency of methoxy
carbonyl group changed from 1743 cm-1 to a strong band at 1741 cm-1 in biodiesel. The C-O
stretching vibration in WSFO showed two asymmetric coupled vibrations1160 cm-1 due to C-
C(=O)-O and 1095 cm-1 due to O-C-C while in their biodiesels these values changed to 1169 and
1014 cm-1 respectively. FTIR results of WSFO and its biodiesel are given in Tables 3.8 and 3.9
respectively.
103
Figures 3.7 and 3.8 indicate that in waste corn oil, absorption frequency of methoxy carbonyl
group changed from 1743 cm-1 to a strong band at 1741 cm-1 in biodiesel. The C-O stretching
vibration in waste corn oil showed two asymmetric coupled vibrations, 1159cm-1 due to C-
C(=O)-O and 1097 cm-1 due to O-C-C while in its biodiesel these values were changed to1169
and 1027 cm-1 respectively. FTIR results of waste corn oil and its biodiesel are given in Tables
3.10 and 3.11 correspondingly.
Comparison of waste soybean oil and its biodiesel that the absorption frequency of methoxy
carbonyl group was changed from 1743 cm-1 in WSBO to a strong band at 1741 cm-1 in biodiesel
as shown in Figures 3.9 and 3.10. The C-O stretching vibration WSBO showed two asymmetric
coupled vibrations 1159 cm-1 due to C-C(=O)-O and 1097 cm-1 due to O-C-C while in its
biodiesel these values changed to 1169 cm-1 and 1026 cm-1 respectively, as shown in FTIR data
Tables 3.12 and 3.13 respectively.
Figures 3.11 and 3.12 indicate that in the case of waste canola oil (WCAO), the absorption
frequency of methoxy carbonyl group varied at 1743 cm-1 in WCAO to 1741 cm-1 in its
biodiesel. The C-O stretching vibration in waste canola oil showed two asymmetric coupled
vibrations 1159 cm-1 due to C-C(=O)-O and 1097 cm-1 due to O-C-C while in its biodiesel these
values were changed to 1169 and 1017 cm-1 respectively. FTIR results of WCAO are given in
Table 3.14 and 3.15, respectively.
The methyl group stretching band, methylene stretching band and methylene bending vibrations
were relatively same in waste cooking oils and their biodiesels but the band of methyl groups
bending vibrations (CH3-) in waste cooking oils were highly different from their biodiesels as
these values were changed approximately from 1376 cm-1 in oil to 1360 cm-1 in their biodiesels.
104
Figure 3.5 FTIR spectrum of waste sunflower oil (WSFO).
Table 3.8 FTIR data of WSFO
S. No. Peak Position (cm-1) Assigned to
1 1743 Methoxy –carbonyl group
2 1160 C-O stretching vibrations due to C-C(=O)-O
3 1095 C-O stretching vibrations due to O-C-C
4 2921 Methyl (CH3) group stretching band
5 2852 Methylene (CH2) stretching band
6 1458 & 1376 Methyl (CH3) group bending vibrations
7 721 Methylene (CH2) bending vibrations
105
Figure 3.6 FTIR Spectrum of biodiesel (methyl esters) derived from waste sun flower oil (ME-WSFO).
Table 3.9 FTIR data of ME-WSFO.
S. No. Peak Position (cm-1) Assigned to
1 1741 Methoxy –carbonyl group
2 1195 Initial formation of (O-CH3) group
3 1435 Methyl ester (O-CH3) peak
4 1169 C-O stretching vibrations due to C-C(=O)-O
5 1014 C-O stretching vibrations due to O-C-C
6 2922 Methyl (CH3) group stretching band
7 2853 Methylene (CH2) stretching band
8 1460 & 1359 Methyl (CH3) group bending vibrations
9 722 Methylene (CH2) bending vibrations
106
Figure 3.7 FTIR spectrum of waste corn oil (WCRO).
Table 3.10 FTIR data of WCRO.
S. No. Peak Position (cm-1) Assigned to
1 1743 Methoxy –carbonyl group
2 1159 C-O stretching vibrations due to C-C(=O)-O
3 1097 C-O stretching vibrations due to O-C-C
4 2922 Methyl (CH3) group stretching band
5 2852 Methylene (CH2) stretching band
6 1459 & 1377 Methyl (CH3) group bending vibrations
7 722 Methylene (CH2) bending vibrations
107
Figure 3.8 FTIR spectrum of Methyl esters (biodiesel) prepared from waste corn oil (ME-WCRO).
Table 3.11 FTIR data of ME-WCRO.
S. No. Peak Position (cm-1) Assigned to
1 1741 Methoxy –carbonyl group
2 1195 Initial formation of (O-CH3) group
3 1435 Methyl ester (O-CH3) peak
4 1169 C-O stretching vibrations due to C-C(=O)-O
5 1017 C-O stretching vibrations due to O-C-C
6 2922 Methyl (CH3) group stretching band
7 2853 Methylene (CH2) stretching band
8 1458 & 1360 Methyl (CH3) group bending vibrations
9 722 Methylene (CH2) bending vibrations
108
Figure 3.9 FTIR spectrum of waste soybean oil (WSBO).
Table 3.12 FTIR data of WSBO.
S. No. Peak Position (cm-1) Assigned to
1 1743 Methoxy –carbonyl group
2 1159 C-O stretching vibrations due to C-C(=O)-O
3 1097 C-O stretching vibrations due to O-C-C
4 2921 Methyl (CH3) group stretching band
5 2852 Methylene (CH2) stretching band
6 1459 & 1376 Methyl (CH3) group bending vibrations
7 721 Methylene (CH2) bending vibrations
109
Figure 3.10 FTIR spectrum of methyl esters (biodiesel) prepared from waste soybean oil (ME-WSBO).
Table 3.13 FTIR data of ME-WSBO.
S. No. Peak Position (cm-1) Assigned to
1 1741 Methoxy –carbonyl group
2 1195 Initial formation of (O-CH3) group
3 1435 Methyl ester (O-CH3) peak
4 1169 C-O stretching vibrations due to C-C(=O)-O
5 1026 C-O stretching vibrations due to O-C-C
6 2922 Methyl (CH3) group stretching band
7 2852 Methylene (CH2) stretching band
8 1458 & 1362 Methyl (CH3) group bending vibrations
9 722 Methylene (CH2) bending vibrations
110
Figure 3.11 FTIR spectrum of waste canola oil (WCAO).
Table 3.14 FTIR data of WCAO.
S. No. Peak Position (cm-1) Assigned to
1 1743 Methoxy –carbonyl group
2 1159 C-O stretching vibrations due to C-C(=O)-O
3 1097 C-O stretching vibrations due to O-C-C
4 2922 Methyl (CH3) group stretching band
5 2852 Methylene (CH2) stretching band
6 1458 & 1376 Methyl (CH3) group bending vibrations
7 721 Methylene (CH2) bending vibrations
111
Figure 3.12 FTIR spectrum of methyl esters (biodiesel) prepared from waste canola oil (ME-WCAO).
Table 3.15 FTIR data of ME-WCAO.
S. No. Peak Position (cm-1) Assigned to
1 1741 Methoxy –carbonyl group
2 1195 Initial formation of (O-CH3) group
3 1435 Methyl ester (O-CH3) peak
4 1169 C-O stretching vibrations due to C-C(=O)-O
5 1017 C-O stretching vibrations due to O-C-C
6 2922 Methyl (CH3) group stretching band
7 2852 Methylene (CH2) stretching band
8 1458 & 1360 Methyl (CH3) group bending vibrations
9 722 Methylene (CH2) bending vibrations
112
3.6. Waste Engine Oil and its Blends
Pakistani waste engine oil and waste vegetable oils were converted into an energy efficient and
environmental friendly fuel which may be utilized as an alternative fuel in diesel engines. In this
study, the waste engine oil was catalytically cracked using Al2O3 in a batch reactor. The
composite fuel blends (CFB15, CFB25, CFB35, CFB45 and CFB55) were prepared from a 40:60
mixture of pretreated cracked waste engine oil and canola oil methyl esters with different
proportions of petroleum diesel. Characterization of the fuel blends is discussed below.
3.6.1 FTIR Analysis
Figures 3.13 and 3.14 represent the scanned FTIR spectra of conventional diesel and CFB
(composite fuel blend of waste engine oil and waste soybean oil), respectively. The
frequency ranges, bond types and family for petroleum diesel and composite fuel blend
(CFB) are given in Table 3.16. In case of petroleum diesel fuel, the strong absorbance peaks
at 2922 and 2852 cm-1 represent C-H stretching. The peak at 1459 cm-1 represents C-H
bending. This is the evidencs which confirms the presence of alkanes. For CFB, the strong
absorbance peaks at 2923 and 2853 cm-1 represent C-H stretching. The peaks at 1459 and
722.99 cm-1 represent C-H bending and C-H out of plane bend, respectively, these absorbance
peaks indicating the presence of alkanes. The presence of alkanes (hydrocarbons) indicates
that the liquids have a potential to be used as fuel.
113
Figure 3.13 FTIR spectrum of diesel
Figure 3.14 FTIR spectrum CFB fuel
Table 3.16 FTIR results for diesel and CFB fuel.
Diesel CFB
Wave number
(cm-1) Bonds Compounds
Wave number
(cm-1) Bonds Compounds
2922 C-H, stretch Alkanes
2923 C-H, stretch Alkanes
2852 C-H, stretch Alkanes
2853 C-H, stretch Alkanes
1459 C-H, bending Alkanes
1459 C-H, bending Alkanes
1377 C-X Fluoride
1359 C-X Fluoride
722 C-H, bending Alkanes 722 C-H, bending Alkanes
114
3.6.2 Fuel properties
The composite fuel blends CFB-15, CFB-25, CFB-35, CFB-45, CFB-55 and petroleum CFB-0
were subjected to different fuel properties as per ASTM standard methods. All the measured
values of the fuel blends were comparable to the specifications of diesel and biodiesel fuels in
accordance with European (EN 4214) and American (ASTM D6751) international standard
limits of biodiesel fuel as shown in Table 3.17 and Figures 3.15-3.20.
Table 3.17 Comparison of fuel properties of CFB fuels with biodiesel fuel standards specification.
Sr. No. Description Density
Viscosity
at 40 oC
Flash
point
Acid
Value
Calorific
Value
Water
Contents
kg/m3 cSt oC mgKOH/g MJ/kg ppm
1 CFB-15 845 3.12 71 0.06 42.51 65
2 CFB-25 848 3.5 82 0.06 42.20 71
3 CFB-35 854 3.82 86 0.08 41.87 85
4 CFB-45 863 4.11 95 0.08 41.72 110
5 CFB-55 870 4.37 103 0.09 41.36 145
6 CFB-0 (Diesel) 840 2.8 66 0.18 42.55 225
7 Method
(ASTM) D-1298 D-445 D-93 D-93 D-240-17 D-976
Specifications
ASTM D-6751 860-900 2.5-6.0 >120 < 0.50 - < 500
EN-14214 860-900 3.5-5.0 >120 < 0.80 - < 500
115
Figure 3.15 Comparison of density of various composite fuel blends derived from a mixture of waste engine
oil and waste canola oil biodiesel to the ASTM and European Standards.
Figure 3.16 Comparison of kinematic viscosity of various composite fuel blends derived from a mixture of
waste engine oil and waste canola oil biodiesel to the ASTM and European Standards.
116
Figure 3.17 Comparison of flash point of various composite fuel blends derived from a mixture of waste
engine oil and waste canola oil biodiesel to the ASTM and European Standards.
Figure 3.18 Comparison of acid value of various composite fuel blends derived from a mixture of waste
engine oil and waste canola oil biodiesel to the ASTM and European Standards.
117
Figure 3.19 Comparison of calorific value of various composite fuel blends derived from a mixture of waste
engine oil and waste canola oil biodiesel to the ASTM and European Standards.
Figure 3.20 Comparison of water contents of various composite fuel blends derived from a mixture of waste
engine oil and waste canola oil biodiesel to the ASTM and European Standards.
118
3.6.3 Combustion Analysis
3.6.3.1 Ignition Delay
Ignition delay is the time difference measured in the degree of the crank angle between the start
of injection and the start of ignition of a fuel in a diesel engine. The value of ignition delay helps
to determine the rate of pressure rise, heat release and maximum pressure (Heywood, 1988). The
variation of the ignition delay for the CFB fuel blends and diesel with respect to engine load
percent is presented in Figure 3.21. The tested fuel blends indicate the decreasing trend of
ignition delay with increase in engine load due to the fact that the engine load increases brake
power. As the brake power increases the heat prevailing inside the cylinder increases, and helps
the fuel air mixture to ignite sooner. As shown in Figure 3.21 the ignition delay is found to
decrease with an increase in the CFB portion in the blends. The observed ignition delay for
diesel was about 10.37 oCA at maximum engine load whereas for CFB-15, CFB-25, CFB-35,
CFB-45 and CFB-55 it was 10.24, 9.54, 9.04, 8.85 and 8.71, respectively, at maximum engine
load.
Figure 3.21 Variations of Ignition Delay vs Engine Load Percent.
119
In the case of diesel and CFB-15 there was no significant difference in the ignition delay and the
value is noticed as fraction of 10 oCA at maximum engine load. The shorter ignition delay is
attributed to the chemical reaction during the injection of the CFB fuel blends at high
temperature. As a result of this phenomenon, the higher molecular weight compounds were
broken down into the product of lower molecular weight. These complex chemical reactions led
to the atomization of lower molecular weight gaseous products on the peripheral region with a
very dense inner core of liquids of higher molecular weight. The rapid vaporization of this lighter
oil at the fringe of the spray spread out the jet, and thus the volatile combustible compounds
ignited earlier and reduced the ignition delay.
3.6.3.2 Heat Release Rate (HRR)
The heat release rate corresponding to every crank angle for the CFB fuel blends and diesel at
maximum engine load conditions is given in Figure 3.22. It is reported that the heat release rate
in the premixed combustion phase is dependent on the mixture formation, ignition delay and the
combustion rate in the initial stages of combustion (Heywood, 1988). Literature also reported
that HRR may or may not reach the second peak in the diffusion combustion phase. In our study,
the second peak did not appear significantly in the diffusion combustion phase.
The maximum heat release for diesel occurred at 366 oCA at maximum engine load. The
occurrence of the maximum heat release rate for the CFB-15, CFB-25, CFB-35, CFB-45 and
CFB-55 were observed at 367.2, 368.5, 369.1, 370.0 and 370.5 oCA, respectively, at maximum
engine load conditions. As the percentage of CFB in the blend increases, the maximum HRR was
found to decrease and the respective crank angle was observed to be advanced.
120
Figure 3.22 Variations of Heat Release Rate vs Crank Angle Degree
3.6.3.3 Maximum Cylinder Pressure
The variation of the maximum cylinder pressure with the engine load percent for the CFB blends
and diesel are given in Figure 3.23. Generally, the maximum cylinder pressure of a diesel engine
depends on the combustion rate in the initial stages of premixed combustion and the proportion
of the fuel accumulated in the delay period (Kumar et al., 2001). The maximum cylinder
pressure for diesel, CFB-15, CFB-25, CFB-35, CFB-45 and CFB-55 at maximum engine load
were 68.74, 71.42, 74.54, 75.84, 76.69 and 78.14 bar, respectively. CFB fuel blends have shown
to have higher values of the maximum cylinder pressure as compared to that of diesel at
maximum engine load conditions. The maximum cylinder pressure for CFB fuel blends was due
to the higher heat released in the premixed combustion phase.
121
Figure 3.23 Variations of Cylinder Pressure vs Engine Load Percent.
3.6.4 Engine Performance
3.6.4.1 Brake Specific Fuel Consumption (BSFC)
Figure 3.24 illustrates the variations of the BSFC of the engine with composite fuel blends and
diesel. For all the fuel blends, the BSFC was found to decrease with increase in the engine brake
power. However, the BSFC of tested blends was increased in comparison to diesel fuel. The
sample CFB15 showed the lowest value of BSFC (318.0 g/kWh) at maximum brake power.
CFB55 exhibited highest fuel consumption (342.8 g/kWh) due to its high viscosity. The BSFC
values for diesel, CFB15, CFB25, CFB35, CFB45 and CFB55 were 310.0 318.2, 326.5, 332.4,
338.6 and 342.8 g/kWh, respectively, at maximum engine load.
122
Figure 3.24 Variations of fuel consumption vs Engine Load Percent.
3.6.4.2 Brake Thermal Efficiency
Figure 3.25 shows the variations between brake thermal efficiency (BTE) with engine brake
power for the various tested fuel blends. At maximum brake power, the engine BTE value for
diesel was observed to be 26.50% and the engine BTE values for CFB15, CFB25, CFB35,
CFB45 and CFB55 were 26.1%, 25.8%, 25.5%, 24.8% and 24.5%, respectively, with a marginal
reduction of 1.51%, 2.64%, 3.77%, 6.41% and 7.55% correspondingly. It was noted that the fuel
blends CFB15 (1.51%) and CFB25 (2.64%) have closer values of BTE in comparison to diesel
fuel. BTE was observed to increase both with increase in the brake power of the engine and with
increase in the CFB proportions in the fuel blends. This is due to decreased calorific values CFB
fuels in comparison to diesel fuel (Qasim et al., 2017). Among all fuel blends tested CFB15 has
shown greater thermal efficiency.
123
Figure 3.25 Variations of brake thermal efficiency vs engine load percent.
3.6.4.3 Exhaust Gas Temperature
The engine exhaust gas temperature (EGT) is shown in Figure 3.26.
Figure 3.26 Variations of exhaust gas temperature vs engine load percent.
At the maximum brake power, the engine EGT values for petroleum diesel was noted 245.2 oC
and values for fuel blends CFB15, CFB25, CFB35, CFB45 and CFB55 were found to be 255.7
oC, 267.1 oC, 280.5 oC, 293.6 oC and 305.9 oC, respectively, with an increase of 4.28%, 8.93%,
124
14.39%, 19.74% and 24.75% correspondingly. It is obvious that the engine needs higher fuel
amounts to generate extra power to overcome the additional load, therefore, engine EGT
increases with fuel blends (Raheman et al., 2013).
Table 3.18 Combustion, performance and emission values at various engine loads.
Engine Combustion Engine Performance Emission Characteristics
No. of
Exp. Load% Samples
Ignition
Delay
Cylinder
Pressure BSFC BTE EGT
CO HC NO Smoke
oCA Bar g/kWh % oC g/kWh g/kWh g/kWh %
1 20.00 CFB0
13.98 52.34
600.0 14.42 180.0
0.58 0.71 6.80 7.99
2 20.00 CFB-15
13.65 55.22
605.9 13.99 190.4
0.58 0.67 7.50 6.52
3 20.00 CFB-25
12.75 59.14
610.2 13.52 200.6
0.59 0.65 7.80 5.51
4 20.00 CFB-35
12.01 60.47
616.4 13.21 210.0
0.57 0.63 7.80 5.12
5 20.00 CFB-45
11.44 61.92
622.3 12.84 220.8
0.56 0.61 7.90 4.92
6 20.00 CFB-55
11.03 63.12
629.6 12.41 228.4
0.57 0.59 8.00 3.58
7 40.00 CFB0
12.75 55.62
410.5 19.20 192.3
0.36 0.56 5.20 11.42
8 40.00 CFB-15
12.65 55.9
415.0 18.78 200.9
0.35 0.53 4.80 10.52
9 40.00 CFB-25
11.76 64.52
421.3 18.28 208.4
0.34 0.50 5.50 9.12
10 40.00 CFB-35
11.04 65.61
427.0 17.75 218.0
0.33 0.49 5.60 8.91
11 40.00 CFB-45
10.43 66.74
433.5 17.48 230.0
0.31 0.47 6.00 8.01
12 40.00 CFB-55
9.98 67.71
440.7 17.01 238.2
0.29 0.46 6.70 7.45
13 60.00 CFB0
11.54 59.84
350.9 21.10 210.9
0.33 0.50 5.40 16.32
14 60.00 CFB-15
11.32 60.57
356.7 20.61 215.5
0.30 0.49 5.90 15.71
15 60.00 CFB-25
10.68 68.51
362.8 20.08 222.3
0.28 0.48 5.80 14.13
16 60.00 CFB-35
9.94 69.75
370.6 19.61 230.1
0.26 0.46 5.90 13.02
17 60.00 CFB-45
9.01 70.81
376.5 19.26 242.2
0.24 0.44 6.40 12.01
18 60.00 CFB-55
9.27 71.92
382.1 18.78 252.6
0.23 0.42 7.00 11.42
19 80.00 CFB0
10.37 63.87
320.4 23.45 225.0
0.34 0.48 6.60 23.51
20 80.00 CFB-15
10.24 67.38
328.3 23.12 230.7
0.36 0.47 6.90 22.17
20 80.00 CFB-25
9.54 70.51
336.0 22.58 242.5
0.33 0.46 7.20 21.45
21 80.00 CFB-35
9.04 71.62
342.0 22.10 250.3
0.30 0.45 7.50 20.41
22 80.00 CFB-45
8.85 72.82
348.6 21.61 260.2
0.27 0.42 7.90 19.51
23 80.00 CFB-55 8.71 73.81 353.2 21.22 270.0 0.25 0.39 8.10 18.55
24 100.0 CFB0 - 77.51 310.0 26.50 245.5 0.34 0.48 6.63 27.92
25 100.0 CFB-15 - 78.19 318.2 26.10 255.7 0.34 0.47 6.94 27.60
26 100.0 CFB-25 - 79.54 326.5 25.80 267.1 0.33 0.46 7.22 26.34
27 100.0 CFB-35 - 81.74 332.4 25.50 280.5 0.30 0.45 7.54 25.54
28 100.0 CFB-45 - 83.49 338.6 24.80 293.6 0.27 0.42 7.92 24.20
29 100.0 CFB-55 - 84.99 342.8 24.50 305.9 0.25 0.39 8.11 22.11
125
Based on experimental data, all the results in connection to combustion, performance and
emission characterististics at various engine load condtions have been summarized in Table 3.18.
3.6.5 Engine Emissions
3.6.5.1 Hydrocarbon Emission
The hydrocarbon (HC) emissions from the diesel engine with diesel and CFB fuel blends are
shown in Figure 3.27. The HC emissions with CFB15, CFB25, CFB35, CFB45, CFB55 and
petroleum diesel were found 0.47, 0.46, 0.45, 0.42, 0.39 and 0.48 g/kW h, respectively, at
maximum engine load. The decrease of 2.08%, 4.16%, 6.25%, 12.5% and 18.75% HC emissions
were observed for CFB15, CFB25, CFB35, CFB45 and CFB55 in comparison to petroleum
diesel. The decrease in HC emissions of the CFB fuels is due to good combustion as a result of
better atomization (Dolanimi et al., 2015).
Figure 3.27 Variation of hydrocarbon emissions vs engine load percent.
126
3.6.5.2 Carbon Monoxide Emission s
Figure 3.28 shows carbon monoxide (CO) emissions from diesel engine with fuel blends CFB15,
CFB25, CFB35, CFB45, CFB55 and petroleum diesel. It is found that CO emissions with
CFB15 was found similar to that of petroleum diesel. The CO emission was found to decrease
with increase in CFB fuel concentrations as well as with increasing brake power. At maximum
brake power CO emission with CFB25, CFB35, CFB45 and CFB55 were observed to decrease
2.94%, 11.76%, 20.58% and 26.47%, respectively, in comparison to CFB15 and petroleum
diesel. The decrease in the carbon monoxide emissions indicates more complete combustion of
the fuel inside the engine (Dolanimi et al., 2015).
Figure 3.28 Variations of Carbon monoxide emissions vs engine load percent.
CO emission of the engine with diesel, CFB15, CFB25, CFB35, CFB45 and CFB55 were found
0.34, 0.34, 0.33, 0.30, 0.27 and 0.25 g/kW h respectively.
127
3.6.5.3 Nitrogen Oxide Emissions
The emission of oxides of nitrogen (NOx) of the engine with diesel was 6.6g/kWh. The NOx
emission values of the engine with diesel, CFB15, CFB25, CFB35, CFB45 and CFB55 were 6.6,
6.9, 7.2, 7.5, 7.9 and 8.1 g/kWh, correspondingly, as shown in Figure 3.29, with a marginal
increases of 4.5%, 9.09%, 13.63%, 19.69% and 22.72%, respectively. NOx emissions were
found to increase with increase in CFB proportion in the fuel blends in comparison to petroleum
diesel. This marginal increase of NOx is due to the higher exhaust gas temperature and higher
oxygen contents in the biodiesel proportion of the CFB fuels (Raheman et al., 2013).
Figure 3.29 Variation of oxides of nitrogen emissions vs engine load percent.
3.6.5.4 Smoke Opacity
Figure 3.30 compares the smoke opacity of the fuel blends CFB15, CFB25, CFB35, CFB45,
CFB55 and petroleum diesel at different engine loads. The smoke density of CFB fuels decreases
as the concentration of composite blends increases. However, the smoke density of CFB blends
is lower than that of petroleum diesel. Among all the fuel blends tested CFB15 shows the highest
128
smoke density and CFB55 was found to have lowest smoke density. At the maximum engine
load, the observed value of smoke density for fuel blends CFB15, CFB25, CFB35, CFB45,
CFB55 and petroleum diesel was observed to be 27.6%, 26.3%, 25.5%, 24.2%, 22.1% and
27.9%, respectively.
Figure 3.30 Variation of smoke opacity vs engine load percent.
3.7 Waste Transformer Oil and its Blends
3.7.1 FTIR Analysis
Figures 3.31 and 3.32 represent the scanned FTIR spectra of conventional diesel and BLF
(mixture of transesterified waste canola and waste transformer oils), respectively. The
frequency ranges, bond types and family for petroleum diesel and transesterified waste oils
(BLF) are given in Table 3.19. In case of petroleum diesel fuel the strong absorbance peaks
at 2922 and 2852 cm-1 represent C-H stretching. The peak at 1459 cm-1 represents C-H
bending. These are the evidence which confirm the presence of alkanes.
129
Figure 3.31 FTIR spectrum of diesel.
Figure 3.32 FTIR spectrum of BLF
Table 3.19 FTIR results of diesel and BLF fuel.
Diesel BLF
Wave number
(cm-1) Bonds Compounds
Wave number
(cm-1) Bonds Compounds
2922 C-H, stretch Alkanes
2922 C-H, stretch Alkanes
2852 C-H, stretch Alkanes
2853 C-H, stretch Alkanes
1459 C-H,
bending Alkanes
1458 C-H,
bending Alkanes
1377 C-X Fluoride
1360 C-X Fluoride
722 C-H,
bending Alkanes
722
C-H,
bending Alkanes
130
For biodiesel like fuel (BLF), the strong absorbance peaks at 2922 and 2853 cm-1 represent
C-H stretch. The peaks at 1458 cm-1 and 722 cm-1 represent C-H bending and C-H out of plane
bend, respectively, these absorbance peaks indicate the presence of alkanes. The presence of C–
H group (hydrocarbons) indicates that the liquids have a potential to be used as fuels
3.7.2 Fuel Properties
Table 3.20 and Figures 3.33-3.38 describe various fuel properties of biodiesel like fuel blends
(BLF15, BLF20, BLF25 and BLF100) and petroleum diesel. The fuel properties were analyzed
by following international standards (ASTM methods). It can be noted from Table 3.20 that all
the measured fuel properties of BLF blends are comparable to those of diesel fuel and all the
measured results were found within European (EN 4214) and American (ASTM D6751)
international standard limits of biodiesel fuel.
Table 3.20 Comparison of fuel properties of BLF fuels with biodiesel fuel standards specs.
Sr. No. Description Density
Viscosity
at 40 oC
Flash
point
Acid
Value
Calorific
Value
Water
Content
kg/m3 cSt oC mgKOH/g MJ/kg ppm
1 BLF-15 836 3.18 72 0.16 42.80 78
2 BLF-20 841 3.24 84 0.18 42.00 85
3 BLF-25 845 3.31 88 0.21 41.40 102
4 BLF-100 886 5.56 166 0.39 39.50 127
5 BLF-0 (Diesel) 834 2.96 60 0.05 43.40 238
6 Method
(ASTM) D-1298 D-445 D-93 D-93 D-240-17 D-976
Specifications
ASTM D-6751 860-900 2.5-6.0 >130 < 0.50 - < 500
EN-14214 860-900 3.5-5.0 >120 < 0.80 - < 500
131
Figure 3.33 Comparison of density of various biodiesel like fuel (BLF) blends derived from a mixture of waste
transformer oil and waste canola oil biodiesel to the ASTM and European Standards.
Figure 3.34 Comparison of kinematic viscosity of various biodiesel like fuel (BLF) blends derived from a
mixture of waste transformer oil and waste canola oil biodiesel to the ASTM and European Standards.
132
Figure 3.35 Comparison of flash point of various biodiesel like fuel (BLF) blends derived from a mixture
of waste transformer oil and waste canola oil biodiesel to the ASTM and European Standards.
Figure 3.36 Comparison of acid value of various biodiesel like fuel (BLF) blends derived from a mixture
of waste transformer oil and waste canola oil biodiesel to the ASTM and European Standards.
.
133
Figure 3.37 Comparison of calorific value of various biodiesel like fuel (BLF) blends derived from a
mixture of waste transformer oil and waste canola oil biodiesel to the ASTM and European Standards.
Figure 3.38 Comparison of water contents of various biodiesel like fuel (BLF) blends derived from a
mixture of waste transformer oil and waste canola oil biodiesel to the ASTM and European Standards.
134
3.7.3 Combustion Characteristics
3.7.3.1 Ignition Delay
Figure 3.39 shows the ignition delay of BLF fuel blends and that of diesel. Ignition delay is
measured in the degree of the crank angle helps to determine the heat release and maximum
pressure rate (Heywood, 1988). The ignition delay of BLF fuel blends was decreased with
increase in the engine load. This trend is authentic, because as the engine load increases the heat
inside the cylinder increases which supports the fuel mixture to ignite earlier. In comparison to
diesel, shorter ignition delay was observed BLF fuel blends. The ignition delay for diesel was
10.6 oCA and for BLF15, BLF-20 & BLF25, it was 10.40, 10.11 & 9.51 oCA, respectively. The
reason for shorter ignition delay was due to the higher cetane number of BLF blends and higher
oxygen contents in biodiesel blends of BLF fuel mixture. This is agreed by Chuahan et al. (2015)
who reported that higher cetane number and higher oxygen contents of biodiesel than diesel
exhibit shorter ignition delay time and allow the fuel for better combustion.
Figure 3.39 Variation of ignition delay vs engine load percent.
135
3.7.3.2 Heat Release Rate
Figure 3.40 shows HRR (heat release rate) corresponding to every crank angle for BLF fuel
blends and diesel at maximum engine load conditions. The maximum HRR was observed for
diesel, BLF15, BLF20 and BLF25 at 364.34, 365.23, 365.67 and 365.84 oCA, respectively.
Higher HRR values were found in BLF blends as compared to diesel due to sufficient oxygen
contents in the biodiesel portion of BLF which catalyzes combustion activation (Heywood,
1988).
Figure 3.40 Variations of heat release rate vs crank angle, degree at maximum engine load
3.7.3.3 Maximum Cylinder Pressure
Variations of maximum cylinder pressure with engine load percent for the BLF blends and diesel
are shown in Figure 3.41. The maximum cylinder pressure for diesel was 76.5 bar and for
BLF15, BLF20 and BLF25 was 77.2, 78.6 and 79.8 bar, respectively, at maximum engine load
136
conditions. Increased cylinder pressure of BLF blends in comparison to that of diesel is due to
higher heat release in the premixed combustion phase because of oxygen catalyzed combustion
activation. The cylinder pressure diesel engine depends mostly on combustion rate in the initial
stages of premixed combustion and the amount of fuel accumulated in the delay period
(Heywood, 1988).
Figure 3.41 Variation of cylinder pressure vs engine load percent.
3.7.4 Engine Performance
3.7.4.1 Brake Specific Fuel Consumption (BSFC)
Figure 3.42 demonstrates the variations of the brake specific fuel consumption with engine load
for petroleum diesel and the blends BLF15, BLF20 and BLF25. It was observed that BSFC was
found to increase with an increase of BLF concentrations in the fuel blends. BSFC value of
diesel, BLF15, BLF20 and BLF25 were measured as 613.21, 632.02, 645.14 and 655.23 g/kW h,
respectively, at 20% load condition which was decreased to 277.32, 284.21, 290.48 and 295.23
g/kW h, respectively, at 100% engine load. BLF15 has shown the minimum fuel consumption
137
value as compared to BLF20 and BLF25 fuel blends. BSFC of BLF15, BLF20 and BLF25 was
found to increase 2.48%, 4.74% and 6.54% as compared to that of diesel fuel. BSFC was found
to decrease with an increase of engine load conditions. This is attributed to the fact that the
engine faces lower heat losses at higher loads (Behera et al., 2014).
Figure 3.42 Variations of BSFC vs engine load percent
3.7.4.2 Brake Thermal Efficiency (BTE)
BTE of diesel engine with diesel, BLF15, BLF20 and BBLF25 at various engine loads is shown
in Figure 3.43. The observed values were 30.52%, 29.91%, 29.45% and 29.02% with diesel,
BLF15, BLF20 and BLF25 at maximum load. The BTE value of BLF15 was found to be very
close to that of diesel fuel. BTE was found to increase with increase in engine load and BTE
values of all BLF fuel blends were found to be 1.99% to 4.91% less than diesel. The decrease in
BTE is because of increased brake power and reduced heat losses of the engine at higher loads
(Prasanna et al., 2015).
138
Figure 3.43 Variations of BTE vs load percent
3.7.4.3 Exhaust Gas Temperature (EGT)
Figure 3.44 shows EGT of a diesel engine when fuelled with diesel, BLF15, BLF20 and BLF25
at various engine loads. EGT values for diesel, BLF15, BLF20, BLF25 were found to be 217 ,
224, 228 , and 232 o C respectively at 20% load of the engine which was increased to 416, 423,
429 and 434 o C, respectively, at maximum engine load. The EGT value of BLF15, BLF20 and
BLF25 was seen 1.68%, 3.12% and 4.33% higher than that of diesel at 100% load. EGT value of
BLF15 was seen close to that of diesel at full load conditions. The increase in EGT with heavier
loads is due to the fact that the engine takes up the additional loads by applying more power
(Behera et al., 2014).
All the measured performance parameters, like BSFC, BTE and EGT, are given in Table 3.21.
The results are technically consistent with the literature (ISO, 1996; Behera et al., 2014;
Raheman et al., 2013)
139
Figure 3.44 Variations of EGT vs load percent
3.7.5 Engine Emissions
3.7.5.1 Hydrocarbons (HC)
In Figure 3.45, the engine shows HC emissions with the fuels BLF15, BLF20, BLF25 and diesel.
With all the fuels tested, the values of HC emissions were continuously lowered from zero to
sixty percent engine load and then increased along with the increase of engine load upto 100%.
Similar trends were seen as observed for CO emissions.
The values of HC emissions with BLF15, BLF20 and BLF25 were observed to be 10.92%,
22.06% and 31.17% respectively, less than petroleum diesel. Among all the blends analyzed, the
blend BLF15 shows minimum reductions of HC emissions as compared with petroleum diesel.
140
Figure 3.45 Variations of HC vs load percent
3.7.5.2 Carbon Monoxide (CO)
The behavior of the engine with respect to CO emissions when operated with diesel, BLF15,
BLF20 and BLF25 at different engine loads is given in Figure 3.46. CO emissions were observed
to decrease with increase in BLF proportions in fuel mixture. The observed values for CO
emissions with HSD, BLF15, BLF20 and BLF25 were 0.033%, 0.029%, 0.028% and 0.027%,
respectively, at 20% load which decreased to 0.022%, 0.015%, 0.016 and 0.018%, respectively,
at 60% load. At maximum load, the CO emissions of BLF15, BLF20 and BLF25 were 3.80%,
5.06% and 6.32% lower compared to diesel fuel. The CO emissions of BLF15 were found closer
to that of diesel but higher than those of BLF20 and BLF25 fuel blends. The average value of
CO emissions of BLF15 was 0.043% at no load condition which was decreased to 0.022% at
60% load which then elevated to 0.086% at maximum load of the engine. The similar trend was
found for BLF20, BLF25 and diesel fuel. The cylinder temperature may be too low at no load
141
conditions, than with increase in loading, it increased due to more fuel injection inside the
cylinder (Heywood, 1988).
Figure 3.46: Variations of CO vs load percent
3.7.5.3 Nitrogen Oxide (NOx)
Nitrogen oxide concentrations in the exhaust gas emissions of the engine operated with BLF15,
BLF20, BLF25 and diesel were 305 ppm, 341 ppm, 372 ppm and 275 ppm, respectively, at 20%
load of the engine which then increased to 1273 ppm, 1297 ppm, 1330 ppm and 1234 ppm,
respectively, at full load conditions as shown in Figure 3.47. The NOx values observed for
BLF15, BLF20 and BLF25 were 3.16%, 5.1% and 7.78% higher than petroleum diesel
correspondingly. The higher values of NOx are due to the higher oxygen contents in biodiesel
fuel blends (Heywood, 1988).
142
Figure 3.47 Variations of NOx vs load percent
3.7.5.4 Smoke Opacity
Figure 3.48 shows the changes in smoke opacity that indicate the soot content present in the
exhaust gases. The smoke opacity for fuel blends BLF15, BLF20, BLF25 and diesel was found
as 6.52%, 5.50%, 5.12% and 5.99%, respectively, at no load conditions.
However, the values were 10.52%, 9.12%, 8.90% and 11.42%, respectively, at 20% load which
were increased to 32.90%, 32.51%, 31.62% and 33.36%, respectively, at maximum load
conditions. It was noted that the smoke opacity decreased with increase in the BLF
concentrations in the fuel mixtures while it was increased with increasing engine load
percentage. All BLF fuel blends have shown lower smoke values as compared to diesel fuel.
Decrease in smoke values with increase in the BLF blend concentrations is attributed to the
higher oxygen contents in the biodiesel fuels (Dhar and Agriwal, 2014).
143
Figure 3.48 Variation of smoke opacity with engine load % for engine fueled with BLF blends.
Table 3.21 Results of combustion, performance, and emission characteristics of the engine fuelled with
biodiesel like fuel (BLF) blends.
Combustion Performance Emissions
No. of
experiments Load% Samples
Ignition
Delay
Cylinder
Pressure BSFC BTE EGT CO HC NO Smoke
oCA Bar g/kWh % oC % ppm ppm %
1 20.00 BLF0
14.23 58.23
613.21 18.62 217.00
0.033 7.02 275.00 11.42
2 20.00 BLF15
13.87 60.12
632.02 18.46 224.00
0.027 6.20 305.00 10.52
3 20.00 BLF20
12.98 62.53
645.14 17.92 228.00
0.028 5.50 341.00 9.12
4 20.00 BLF25
11.99 64.21
655.23 17.08 232.00
0.030 4.23 372.00 8.90
5 40.00 BLF0
13.42 64.52
378.71 25.12 240.00
0.023 6.21 422.00 16.32
6 40.00 BLF15
12.81 65.68
386.08 24.85 245.00
0.020 5.82 452.00 15.70
7 40.00 BLF20
12.45 66.71
392.46 24.45 251.00
0.021 4.91 485.00 14.13
8 40.00 BLF25
11.32 67.57
399.88 23.87 258.00
0.022 3.72 518.00 13.02
9 60.00 BLF0
12.15 68.31
312.40 30.02 280.00
0.022 5.53 670.00 23.50
10 60.00 BLF15
11.65 69.41
318.35 29.50 285.00
0.015 4.01 698.00 22.17
11 60.00 BLF20
11.32 70.52
325.08 28.91 292.00
0.016 3.58 742.00 21.45
12 60.00 BLF25
10.23 71.61
332.15 29.88 299.00
0.018 2.54 771.00 20.41
13 80.00 BLF0
11.23 72.12
296.12 31.70 340.00
0.025 7.49 965.00 28.50
14 80.00 BLF15
10.98 73.19
302.84 30.98 347.00
0.018 6.82 998.00 27.61
15 80.00 BLF20
10.64 74.28
308.99 30.36 352.00
0.020 5.48 1045.00 26.30
16 80.00 BLF25
9.88 75.36
314.22 29.88 359.00
0.022 4.36 1065.00 25.52
17 100.00 BLF0
10.60 76.5
277.32 30.52 416.00
0.086 18.22 1234.00 33.36
18 100.00 BLF15
10.40 77.2
284.20 29.91 423.00
0.076 16.23 1271.00 32.90
19 100.00 BLF20
10.11 78.6
290.48 29.45 429.00
0.079 14.22 1297.00 32.51
20 100.00 BLF25 9.51 79.8 295.23 29.02 434.00 0.083 12.54 1330.00 31.62
144
All the measured engine combustion, performance and emission values are tabulated in Table
3.21. It is experimentally observed that high smoke opacity of petroleum diesel is due to the
higher concentrations of sulfur contents as compared to biodiesel fuel blends (Hirkude and
Padalkar, 2012).
3.8 Waste Tyre Pyrolysis Oil and its Blends
The waste tyre pyrolysis liquid (light fraction) was collected from a commercial tyre pyrolysis
plant and biodiesel was prepared from waste soybean oil. The fuel blends (FMWO10, FMWO20,
FMWO30, FMWO40 and FMWO50) were prepared from a 30:70 mixture of waste tyre
pyrolysis liquid and waste soybean oil methyl esters with different proportions of mineral diesel.
The mixture was called the fuel mixture of waste oils (FMWO).
3.8.1 FTIR Analysis
The FTIR analysis was carried out for FMWO and diesel samples as explained in Chapter 2.
FTIR analysis confirms that the functional groups present in FMWO are almost entirely alkanes
(hydrocarbons) and halides. Comparable infrared absorption spectra for FMWO and diesel are
shown in Figures 3.49 and 3.50. The frequencies of the absorption are given in Table 3.22.
Similar work has been reported by Kapura et al. (2014) and Bhatt & Patel. (2012).
145
Figure 3.49 FTIR spectrum of diesel
Figure 3.50 FTIR spectrum of FMWO
Table 3.22 FTIR results for diesel and FMWO
Diesel FMWO
Wave number
(cm-1) Bonds Compounds
Wave number
(cm-1) Bonds Compounds
2922 C-H, stretch Alkanes
2922 C-H, stretch Alkanes
2852 C-H, stretch Alkanes
2853 C-H, stretch Alkanes
1459 C-H,
bending Alkanes
1457 C-H,
bending Alkanes
1377 C-X Fluoride
1361 C-X Fluoride
722 C-H,
bending Alkanes
721
C-H,
bending Alkanes
146
3.8.2 Fuel Properties
The fuel blends FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50 were analyzed for
physicochemical properties as shown in Table 3.23 and Figures 3.51-3.56. The obtained results
of the fuel blends were compared with international fuel European (EN 14214) and American
(ASTM 6751) standards. It was observed that all the measured values of the fuel blends were
found within the specified limits of above mentioned standard fuel specifications.
Table 3.23 Comparison of fuel properties of FMWO blends with biodiesel fuel standards.
Sr. No. Description Density
Viscosity
at 40 oC
Flash
point
Acid
Value
Calorific
Value
Water
Contents
kg/m3 cSt oC mgKOH/g MJ/kg mgl-1
1 Method (ASTM) D-1298 D-445 D-93 D-974 D-240-17 D-95
2 FMWO10 842 3.34 78 0.10 42.62 65
3 FMWO20 847 3.46 84 0.14 42.41 72
4 FMWO30 862 3.80 87 0.12 41.83 87
5 FMWO40 869 4.12 96 0.16 41.62 110
6 FMWO50 874 4.30 102 0.22 41.28 135
7 FMWO0(Diesel) 839 3.18 72 D-93 42.85 50
Specifications
ASTM D-6751 860-900 2.5-6.0 >120 < 0.50 - < 500
EN 14214 860-900 3.5-5.0 >120 < 0.80 - < 500
Figure 3.51 Comparison of density of various fuel blends derived from a mixture of waste tyre pyrolysis
oil and waste cooking oil biodiesel to the ASTM and European Standards.
147
Figure 3.52 Comparison of kinematic viscosity of various fuel blends derived from a mixture of waste tyre
pyrolysis oil and waste cooking oil biodiesel to the ASTM and European Standards.
Figure 3.53 Comparison of flash point of various fuel blends derived from a mixture of waste tyre
pyrolysis oil and waste cooking oil biodiesel to the ASTM and European Standards.
148
Figure 3.54 Comparison of acid value of various fuel blends derived from a mixture of waste tyre
pyrolysis oil and waste cooking oil biodiesel to the ASTM and European Standards.
Figure 3.55 Comparison of calorific value of various fuel blends derived from a mixture of waste tyre
pyrolysis oil and waste cooking oil biodiesel to the ASTM and European Standards
149
Figure 3.56 Comparison of water contents of various fuel blends derived from a mixture of waste tyre
pyrolysis oil and waste cooking oil biodiesel to the ASTM and European Standards.
3.8.3 Combustion Characteristics
3.8.3.1 Ignition Delay
The variation of the ignition delay for diesel and FMWO fuel blends at different engine load
conditions is illustrated in Figure 3.57. The ignition delay was found to be the shorter for FMWO
fuels as compared to diesel at maximum engine load conditions. The more viscous FMWO has a
complex molecular structure that might produce larger spray angles and shorter penetrations
compared with those of diesel. Similar results have been reported by Ryan and Bagby (1993).
The compounds with higher cetane index might have ignited earlier, resulting in shorter ignition
delay. At maximum engine load conditions, the ignition delay values for the diesel, FMWO-10,
FMWO-20, FMWO-30, FMWO-40 and FMWO-50 were 11.34, 10.81, 9.92, 9.24, 8.82 and 8.71
oCA, respectively, at maximum engine load conditions.
150
Figure 3.57 Variation of ignition delay with engine load % for engine fueled with FMWO blends.
3.8.3.2 Heat Release Rate (HRR)
The major factors affecting the heat release rate in a diesel engine are predominantly density,
ignition delay, bulk modulus characteristics and adiabatic flame temperature (Caresana, 2011;
Seppo et al., 2004; Gumus, 2010; Gumus et al., 2010; Kannan et al., 2011; Bari et al., 2004).
The heat release rate of diesel at the original injection timing was found to be 363 oCA, while the
HRR values for FMWO-10, FMWO-20, FMWO-30, FMWO-40 and FMWO-50 was observed
363.4, 365.0, 365.6, 366.0 and 366.7 oCA at maximum engine load conditions as presented in
Figure 3.58. The higher heat release of FMWO-50 at the particular injection timing was due to
bulk modulus characteristics of the fuel or different adiabatic flame temperatures.
151
Figure 3.58 Variation in heat release rate with engine load % for engine fueled with Different FMWO fuel
blends.
3.8.3.3 Maximum Cylinder Pressure
The variations of the maximum cylinder pressure with engine load percent for diesel and FMWO
fuel blends is illustrated in Figure 3.59. The maximum cylinder pressures for diesel and FMWO-
10, FMWO-20, FMWO-30, FMWO-40 and FMWO-50 are 77.51, 78.19, 79.54, 81.74, 83.49 and
84.99 bar at maximum engine load conditions. As compared to diesel, FMWO fuel blends have
shown higher values of maximum cylinder pressure due to is due to higher heat release in the
premixed combustion phase.
152
Figure 3.59 Variation of maximum cylinder pressure with engine load % for engine fueled with different
FMWO fuel blends.
3.8.4 Engine Performance
3.8.4.1 Brake Specific Fuel Consumption
BSFC is a very important factor to compare the fuels having different densities and heating
values (Agrawal 2007). Figure 3.60 shows the variations of the BSFC for diesel and FMWO
blends. The BSFC for diesel was 343.25 g/kWh at 100% load and it was 344.63, 350.12, 362.30,
367.64 and 370.25 g/kWh for the FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50,
respectively, at full load conditions. BSFC was found to decrease as the engine load was
increased. FMWO10 has shown lowest BSFC among all the blends measured. FMWO10 has a
comparable BSFC value to that of diesel due to better combustion and higher heating values in
comparison to other fuel blends. The FMWO40 and FMWO50 have higher fuel consumption
values due to lower heating values.
153
Figure 3.60 Variations of BSFC vs engine load%.
3.8.4.2 Brake Thermal Efficiency (BTE)
BTE of FMWO blends was compared with diesel fuel as shown in Figure 3.61. BTE of the
engine at full load was found 29.61% for diesel and 29.24%, 29.12%, 28.67.16%, 28.90% and
28.92% for FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50, respectively, at full
load. The BTE of the fuel blends was found to be lower than diesel. This may be due to the lower
calorific value of the fuel blends. The FMWO10 has shown better performance in comparison to
all other fuels analyzed. The increase in BTE value for FMWO10 in comparison to other fuel
blends might be attributed to its lower viscosity and better fuel atomization.
154
Figure 3.61 Variations of BTE with engine load%.
3.8.4.3 Exhaust Gas Temperature
The exhaust gas temperature (EGT) is a good indicator for amount of heat lost with exhaust
gases (Murugan et al., 2008). Variations of EGT with respect to engine load percent are shown
in Figure 3.62. The EGT was found 352, 377, 385, 376, 368 and 379 oC for diesel, and
FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50, respectively, at full load. The figure
shows that the EGT for all fuel blends was increased as the engine load was increased, however
the EGT of diesel was found lower than FMWO blends. This indicates that the combustion of
FMWO blends might be delayed due to higher densities and viscosities.
155
Figure 3.62 Variations of EGT with engine load%.
3.8.5 Emissions
3.8.5.1 Hydrocarbons
The hydrocarbon (HC) emissions are created as a result of incomplete combustion inside the
combustion chamber, variations in the equivalence ratio and deposits on the internal combustion
chamber walls (Murugan et al., 2008). The variations of HC emissions with engine load percent
for diesel and FMWO blends are plotted in Figure 3.63. It was found that the HC emissions were
decreased with increase in engine load. The HC emissions for diesel, FMWO10, FMWO20,
FMWO30, FMWO40 and FMWO50 were observed 0.032, 0.030, 0.028, 0.029, 0.031, 0.027
g/kWh, respectively, at full load. The FMWO10, FMWO20, FMWO30, FMWO40 and
FMWO50 blends have shown 6.25%, 12.5%, 9.37%, 3.12% and 15.62% lower emissions than
diesel. This indicates more complete combustions of the studied fuel blends.
156
Figure 3.63 Variation of HC emissions with engine load %
3.8.5.2 Carbon Monoxide
Figure 3.64 shows carbon monoxide (CO) emissions for diesel and FMWO blends. The CO
emissions for diesel, FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50 were 0.012,
0.010, 0.0080, 0.0092, 0.0086 and 0.0084 g/kWh respectively at full load conditions. The CO
emissions were found to decrease from no load to 100% load. All the FMWO blends show 16.5-
33.2% lower CO emissions in comparison to diesel. This indicates complete mixing and
complete combustion of the fuel blends.
157
Figure 3.64 Variation of CO emissions with engine load %.
3.8.5.3 Nitrogen Oxide (NOx)
The availability of oxygen, combustion duration, temperature, pressure and higher compression
ratio are the factors which affect nitric oxide emissions (Murugan et al., 2008). The variations of
NOx emissions with engine load for diesel and FMWO are plotted in Figure 3.65. The CO
emissions for diesel, FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50 were observed
5.41, 5.62, 5.72, 5.70, 5.71 and 5.72 g/kWh, respectively, at maximum load conditions. NOx
emissions were found to increase as the engine load was increased. All the FMWO fuel blends
have shown marginally higher NOx emissions as compared to diesel might be due to higher
oxygen contents in the biodiesel portion of the blends.
158
Figure 3.65 Variation of NOx emissions with engine load %.
3.8.5.4 Smoke Opacity
Figure 3.66 depicts the smoke emissions of FMWO fuel blends and diesel. Generally, smoke
opacity occurs due to the incomplete combustion inside the combustion chamber of the engine
(Murugan et al., 2008).
Figure 3.66 Variation of smoke opacity with engine load %.
159
The smoke emissions for diesel, FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50
were 58.21%, 55.56%, 57.14%, 55.23%, 56.02% and 55.33%, respectively, at full load.
Table 3.24 Results of combustion, performance, and emission characteristics of the engine fuelled with the
fuel blends derived from waste tyre pyrolysis oil.
Engine Combustion Engine Performance Emission Characteristics
No. of
Exp. Load% Samples
Ignition
Delay
Cylinder
Presure BSFC BTE EGT
CO HC NO Smoke
oCA Bar g/kWh % oC g/kWh g/kWh g/kWh %
1 20.00 FMWO-0
14.66 59.58
625.00 17.85 203.00
0.051 0.098 3.29 18.52
2 20.00 FMWO-10
14.13 61.23
632.00 17.68 206.00
0.049 0.097 3.42 18.10
3 20.00 FMWO-20
13.17 63.52
640.00 17.22 204.00
0.048 0.096 3.62 17.57
4 20.00 FMWO-30
12.31 65.32
652.00 16.81 208.00
0.046 0.097 3.58 18.20
5 20.00 FMWO-40
11.38 67.81
648.00 17.35 205.00
0.050 0.097 3.66 17.78
6 20.00 FMWO-50
11.03 69.23
642.00 17.55 212.00
0.047 0.096 3.67 17.92
7 40.00 FMWO-0
13.25 65.47
450.00 22.92 221.00
0.046 0.088 3.88 26.30
8 40.00 FMWO-10
12.63 66.58
460.00 22.56 226.00
0.039 0.087 3.89 25.66
9 40.00 FMWO-20
11.74 68.71
470.00 21.23 225.00
0.041 0.085 4.25 24.62
10 40.00 FMWO-30
11.12 69.74
481.00 21.25 228.00
0.044 0.086 4.12 25.48
11 40.00 FMWO-40
10.51 72.54
475.00 22.01 231.00
0.043 0.087 4.67 25.98
12 40.00 FMWO-50
10.13 74.58
470.00 21.50 233.00
0.042 0.086 4.68 26.52
13 60.00 FMWO-0
12.07 69.41
374.00 27.92 240.00
0.033 0.071 4.46 38.21
14 60.00 FMWO-10
11.58 70.42
380.00 27.70 252.00
0.030 0.068 4.71 37.50
15 60.00 FMWO-20
10.71 72.52
384.00 27.01 256.00
0.028 0.069 4.62 37.60
16 60.00 FMWO-30
10.09 73.82
389.00 26.50 253.00
0.031 0.065 4.78 37.77
17 60.00 FMWO-40
9.71 75.62
386.00 26.75 251.00
0.032 0.069 4.79 36.86
18 60.00 FMWO-50
9.43 77.41
380.00 27.02 258.00
0.029 0.070 4.82 37.80
19 80.00 FMWO-0
11.34 74.12
355.00 28.25 290.00
0.025 0.048 4.97 42.32
20 80.00 FMWO-10
10.81 74.21
358.00 28.02 296.00
0.019 0.046 5.21 41.15
20 80.00 FMWO-20
9.92 75.64
367.00 27.85 305.00
0.022 0.047 5.46 40.23
21 80.00 FMWO-30
9.24 77.38
375.00 27.08 320.00
0.023 0.040 4.98 41.55
22 80.00 FMWO-40
8.82 79.48
369.00 27.83 317.00
0.020 0.046 4.95 40.70
23 80.00 FMWO-50
8.71 81.24
361.00 28.24 322.00
0.024 0.047 5.36 40.33
24 100.00 FMWO-0
- 77.51
343.25 29.61 352.00
0.012 0.032 5.41 58.21
25 100.00 FMWO-10
- 78.19
344.63 29.24 377.00
0.010 0.030 5.62 55.56
26 100.00 FMWO-20
- 79.54
350.12 29.12 385.00
0.008 0.028 5.72 57.14
27 100.00 FMWO-30
- 81.74
362.30 28.67 376.00
0.009 0.029 5.70 55.23
28 100.00 FMWO-40
- 83.49
367.00 28.90 368.00
0.011 0.030 5.71 56.02
29 100.00 FMWO-50 - 84.99 370.25 29.11 379.00 0.009 0.027 5.68 55.33
160
Smoke emissions were found to increase as the engine load was increased. Lower smoke
emissions were noticed for FMWO blends as compared to diesel. This indicates the better
combustion of the fuel blends in the combustion chamber of the engine.
Based on experimental data, all the measured values of combustion, performance and emission
characteristics at various engine load conditions have been summarized in Table 3.24.
3.9 Waste Cooking Oil Biodiesel and its Blends
Objective of these investigations was to prepare biodiesel from waste cooking oil and to study
the performance characteristics in a diesel engine without any modification. In this work,
biodiesel was prepared from waste cooking oil collected from a local restaurant in Multan,
Pakistan. The prepared biodiesel was blended with petroleum diesel at different proportions and
characterized for FTIR analysis, fuel properties using ASTM standard methods as well as
performance and emission characteristics of a diesel engine fuelled with pure diesel B0, biodiesel
blends B10, B15 and B20 fuels.
3.9.1 FTIR Analysis
Figures 3.67 & 3.68 represent the scanned FTIR spectra of conventional diesel and WCOB
(waste cooking oil biodiesel). FTIR analysis confirms that the functional groups present in
WCOB sample were almost alkanes (hydrocarbons) and halides. Comparable infrared absorption
spectrums were observed for WCOB and diesel. The data of the peaks are given in Table 3.25.
161
Figure 3.67 FTIR spectrum of diesel.
Figure 3.68 FTIR Spectrum of WCOB.
Table 3.25 FTIR Data for diesel and WCOB.
Diesel WCO
Wave number
(cm-1) Bonds Compounds
Wave number
(cm-1) Bonds Compounds
2922 C-H, stretch Alkanes
2922 C-H, stretch Alkanes
2852 C-H, stretch Alkanes
2853 C-H, stretch Alkanes
1459 C-H,
bending Alkanes
1458 C-H,
bending Alkanes
1377 C-X Fluoride
1360 C-X Fluoride
722 C-H,
bending Alkanes
722
C-H,
bending Alkanes
162
3.9.2 Fuel Properties
The fuel properties of waste cooking oil biodiesel (WCOB) blends of B-10, B-15, B-20 and
petroleum diesel are presented in Table 3.26 and Figures 3.69-3.74, respectively. The results of
the fuel blends were compared with international fuel European (EN 14214) and American
(ASTM 6751) standards. It was found that all the values of the fuel blends were found within the
allowable specified limits of international standards.
Table 3.26 Comparison of fuel properties of WCOB blends with biodiesel fuel standards.
Sr. No. Description Density
Viscosity
at 40 oC
Flash
point
Acid
Value
Calorific
Value
Water
Contents
kg/m3 cSt oC mgKOH/g KJ/kg mgl-1
1 Method
(ASTM) D-1298 D-445 D-93 D-974 D-240-17 D-95
2 WCOB0 (HSD) 834 2.66 62 0.09 43200 75
3 WCOB10 838 2.99 66 0.19 42370 150
4 WCOB15 842 3.08 71 0.22 41800 170
5 WCOB20 848 3.14 82 0.25 41325 188
6 WCOB100 861 4.5 165 0.44 37840 410
Specifications
ASTM D-6751 860-900 2.5-6.0 >120 < 0.50 - < 500
EN 14214 860-900 3.5-5.0 >120 < 0.80 - < 500
Figure 3.69 Comparison of density of various fuel blends derived from a mixture of waste cooking oil
biodiesel and diesel to the ASTM and European Standards.
163
Figure 3.70 Comparison of kinematic viscosity of various fuel blends derived from a mixture of waste
cooking oil biodiesel and diesel to the ASTM and European Standards.
Figure 3.71 Comparison of flash point of various fuel blends derived from a mixture of waste cooking oil
biodiesel and diesel to the ASTM and European Standards.
164
Figure 3.72 Comparison of acid value of various fuel blends derived from a mixture of waste cooking oil
biodiesel and diesel to the ASTM and European Standards.
Figure 3.73 Comparison of calorific value of various fuel blends derived from a mixture of waste cooking
oil biodiesel and diesel to the ASTM and European Standards.
165
Figure 3.74 Comparison of water contents of various fuel blends derived from a mixture of waste
cooking oil biodiesel and diesel to the ASTM and European Standards.
3.9.3 Combustion Characteristics
3.9.3.1 Ignition Delay
The variation of the ignition delay for diesel and waste cooking oil biodiesel blends (WCOB),
commonly coded as B-10, B-15 and B-20 at maximum engine load percent is given in Figure
3.75. The ignition delays for diesel, B-10, B-15 and B-20 were found 10.22, 10.01, 9.88 and 9.55
oCA, respectively, at full load conditions. The reason for shorter ignition delay of waste cooking
oil derived biodiesel blends might be attributed to higher cetane number of the fuel blends and
higher oxygen contents in biodiesel proportion of the fuel mixtures. This was agreed by Chuahan
et al., (2015) who reported that higher cetane number and higher oxygen contents of biodiesel
than diesel exhibit shorter ignition delay time and the fuel rendered better combustion.
166
Figure 3.75 Variation of the ignition delay with engine load % for an engine fueled with different waste
cooking oil derived biodiesel blends and petroleum diesel.
3.9.3.2 Heat Release Rate
The variation of heat release rate with crank angle at full load conditions with diesel and
biodiesel blends is presented in Figure 3.76. The maximum HRR for diesel, B-10, B-15 and B-20
were found 370.2, 370.8, 371.6 and 372.5 oCA respectively, at maximum load conditions. Higher
HRR values were observed in B-10, B-15 and B-20 as compared to diesel due to higher oxygen
contents in biodiesel which catalyzed the combustion activation (Heywood, 1988).
It can be observed from the figure that the occurrence of maximum heat release rate was found to
be little earlier for the biodiesel blends derived from waste cooking oil than that of diesel due to
the bulk modulus characteristics of biodiesel blends (Kannan and Anand, 2011).
167
Figure 3.76 Variation of heat release rate with crank angle at maximum engine load% for engine fueled
with diesel and different waste cooking oil derived biodiesel blends.
3.9.3.3 Maximum Cylinder Pressure
Figure 3.77 illustrates the variation of maximum cylinder pressure with various engine load
percent for diesel and biodiesel blends derived from waste cooking oil. The maximum cylinder
pressure was observed to increase with increase in engine load percent due to the fact that the
engine gained more heat with more load. The maximum cylinder pressure of diesel, B-10, B-15
and B-20 were 75.61, 76.81, 77.91 and 78.77 bar, respectively, at maximum load conditions. It
was noted that biodiesel blends have exhibited higher cylinder pressure than diesel fuel due to
higher cetane index and extra oxygen contents of biodiesel.
168
Figure 3.77 Variation of maximum cylinder pressure with engine load % for engine fueled with
Different biodiesel blends derived from waste cooking oil.
3.9.4 Engine Performance
3.9.4.1 Brake Specific Fuel Consumption
Figure 3.78 shows the variations of the brake specific fuel consumption with engine load for
petroleum diesel and biodiesel blends B10, B15 and B20. It was observed that with an increase
of biodiesel proportion in the fuel blends, BSFC was found to increase. BSFC values of diesel,
B10, B15 and B20 were 271.36, 279.40, 284.22 and 292.66 g/kW h, respectively, at maximum
load. The BSFC values of B10, B15 and B20 were 2.96%, 4.73% and 7.85% higher than those
with petroleum diesel. The 10% blend shown the minimum BSFC value among the tested fuel
blends. With increase in the loading for all the fuels tested BSFC was found to decrease sharply.
This may be due to heat losses at higher loads.
169
Figure 3.78 Variation of brake specific fuel consumption with various loads for an engine
3.9.4.2 Brake Thermal Efficiency
BTE behavior of diesel engine when operated with diesel, B10, B15 and B20 at various engine
loads is plotted in Figure 3.79.
Figure 3.79 Variations of BTE with engine load
170
With diesel, B10, B15 and B20, the BTE value were found to be 32.68%, 32.18%, 31.88% and
31.51%, respectively, at full load. As compared to diesel, the BTE values of fuel blends were
decreased with increasing levels of biodiesel proportions in the blends. This is due to the less
heating (calorific values) of the blends. There was improvement in BTE with increase in engine
load because the engine had lost its less power along with the engine load increase.
3.9.4.3 Exhaust Gas Temperature
Variations of EGT of a diesel engine when operated with diesel, B10, B15, B20 at various
engine loads are shown in Figure 3.80.
Figure 3.80 Variations of EGT with engine load%
EGT was observed to rise with increased concentrations of biodiesel in the blends as well as with
increase in engine loads. The EGT values of B10, B15 and B20 were found 306 o C, 308 o C and
312 o C, respectively, at maximum load, which were 4.43%, 5.11% and 6.4% higher than that
with diesel (293 o C). The increase in EGT with heavier loads is due to the fact that the engine
requires high amount of fuel to create extra power to take up the additional loads.
171
Based on experimental data, all the measured values of combustion, performance and emission
characteristics at various engine load conditions have been summarized in Table 3.27.
Table 3.27 Results of combustion, performance, and emission characteristics of the engine fuelled with waste
cooking oil biodiesel blends.
Combustion Performance Emissions
No. of
Experiments Load% Samples
Ignition.
Delay
Cylinder
Pressure BSFC BTE EGT
CO HC NO Smoke
oCA Bar g/kWh %
oC % ppm ppm %
1 20.00 B0
13.35 57.41
560.23 18.56 220.00
0.029 5.12 269.00 17.51
2 20.00 B-10
13.10 59.12
580.34 17.42 222.00
0.028 5.73 313.00 17.09
3 20.00 B-15
12.67 62.42
595.00 16.91 224.00
0.028 5.28 338.00 16.57
4 20.00 B-20
11.99 64.32
610.11 16.08 226.00
0.027 4.83 373.00 17.19
5 40.00 B0
12.23 63.21
380.52 24.11 265.00
0.019 4.54 424.00 25.29
6 40.00 B-10
12.04 64.92
390.00 23.84 267.00
0.018 4.10 458.00 24.65
7 40.00 B-15
11.71 65.99
400.24 23.45 269.00
0.017 3.71 481.00 23.61
8 40.00 B-20
11.04 67.61
408.33 23.37 271.00
0.016 3.18 516.00 24.47
9 60.00 B0
11.32 67.45
301.36 29.02 278.00
0.021 3.52 681.00 37.19
10 60.00 B-10
11.09 68.91
308.47 28.48 280.00
0.018 3.20 688.00 36.48
11 60.00 B-15
10.64 70.51
318.76 27.89 282.00
0.017 2.97 747.00 36.58
12 60.00 B-20
10.21 71.63
326.21 27.88 284.00
0.016 2.54 769.00 36.75
13 80.00 B0
10.55 71.22
288.49 30.70 286.00
0.021 2.98 972.00 41.29
14 80.00 B-10
10.33 72.88
292.32 29.98 288.00
0.019 2.97 993.00 40.14
15 80.00 B-15
9.97 73.92
290.44 29.38 289.00
0.020 2.51 1042.00 39.22
16 80.00 B-20
9.72 75.41
298.65 29.08 291.00
0.021 2.01 1058.00 40.54
17 100.00 B0
10.22 75.61
271.36 32.68 293.00
0.073 10.65 1065.00 57.18
18 100.00 B-10
10.01 76.81
279.40 32.18 306.00
0.072 9.91 1098.00 54.55
19 100.00 B-15
9.88 77.91
284.22 31.88 308.00
0.071 9.45 1119.00 56.13
20 100.00 B-20 9.55 78.77 292.66 31.51 312.00
0.070 8.76 1142.00 54.22
3.9.5 Engine Emissions
3.9.5.1 Hydrocarbons
The unburnt HC emission of the diesel engine fuelled with petroleum diesel and biodiesel blends
with various engine loads is presented in Figure 3.81. The HC emission for diesel, B-10, B-15
and B-20 were found 10.65, 9.91, 9.45 and 8.76 ppm, respectively, at full load conditions. B-20
fuel blend has shown the lowest hydrocarbon emissions among all fuel blends tested. This may
172
be due to better mixing of fuel air mixture leading to more complete combustion. Because of the
presence of higher concentrations of oxygen in the fuel blends containing higher proportions of
oxygen, some of the higher molecular weight compounds may not breakup and might undergo
complete combustion.
Figure 3.81 Variation of HC emission with various load conditions for an engine fueled with diesel and
different waste cooking oil derived biodiesel blends.
3.9.5.2 Carbon Monoxide Emissions
CO emissions with various engine loads are given in Figure 3.82. As mentioned earlier, CO
emissions are reduced in the exhaust when using biodiesel fuel due to the reason that biodiesel
fuels contain more oxygen than diesel fuel and this results in more complete combustion in
comparison to that of diesel. CO emissions in diesel, B-10, B-15 and B-20 were 0.073%,
0.072%, 0.071% and 0.070%, respectively, at maximum load conditions. Here, it is well evident
that biodiesel blends have shown slightly lower emissions as compared to diesel fuels.
173
Figure 3.82 Variation of CO emission with various load conditions for an engine fueled with diesel and
different waste cooking oil derived biodiesel blends.
3.9.5.3 Nitrogen Oxide Emissions
Nitrogen oxide concentrations in the exhaust gas emissions of diesel engine operated with diesel
and biodiesel blends are given in Figure 3.83.
Figure 3.83 Variation of NOx emission with various load conditions for an engine fueled with diesel and
different waste cooking oil derived biodiesel blends.
174
NO emission for diesel, B-10, B-15 and B-20 was found 1065 ppm, 1098 ppm, 1119 ppm and
1142 ppm, respectively, at full load conditions. The NOx values were 3.09%, 5.07% and 7.23%
higher than petroleum diesel. The higher values of NOx might be due to the higher oxygen
contents in biodiesel fuel blends (Kannan and Anand, 2011).
3.9.5.4 Smoke Opacity
Smoke opacity indicates soot contents in the exhaust gas emissions. The smoke opacity at
various engine load conditions are given in Figure 3.84.
Figure 3.84 Variation of smoke emission with various load conditions for an engine fueled with diesel and
different waste cooking oil derived biodiesel blends.
The smoke opacity in the exhaust gas emissions for fuel blends B-10, B-15 B-20 and diesel were
56.55%, 56.13%, 54.22% and 57.18%, respectively, at maximum load conditions. It was noted
that the smoke opacity decreased with increase in the concentrations of biodiesel proportions in
the fuel mixtures while it increased with increasing engine load percentage. Biodiesel blends
have shown lesser smoke emissions as compared to that of diesel. This decrease in smoke values
with increase in the biodiesel concentrations was associated with the higher contents of oxygen
175
in the biodiesel fuel blends (Chauhan et al., 2012) and higher smoke emissions of petroleum
diesel was due to the higher concentrations of sulfur contents as compared to biodiesel fuel
blends (Raheman et al., 2013).
176
Conclusions
Based upon the work reported in this thesis, the following conclusions may be made:
Method Development for Recycling of Waste Engine Oils
i. A new method has been developed to recycle waste automotive engine oils into valuable
base oil by using cheaply available Rice Husk Ash (RHA) as raw material.
ii. Optimum results were observed only with 6% activated RHA.
iii. The oil regenerated with this concentration has almost the similar results to that of the
virgin base oil.
iv. The conventional existing methods of re-refining of waste lubricating oils namely acid
clay and distillation clay were compared with the novel rice husk ash clay method of
waste oil re-refining. The advantage of using an activated rice husk ash is that it does not
react with base oils.
v. This new recycling method is very much cost effective, simple, environmental friendly
and can be operated at atmospheric temperature.
vi. The regenerated oil with 1% acetic acid is more beneficial than that of 1% sulfuric acid,
because acetic acid has shown almost no reaction with base oils. However, sulphuric acid
reacts vigorously with the used oil hence decreases the yield of base oil.
vii. Another advantage of using acetic acid is that it does not emit poisonous gases like sulfur
dioxide to the atmosphere. After adding the required additives, the rice husk ash method
gives recycled oil having the potential to be reused in motorcycles, cars and other
engines.
177
Composite Fuel Blends (CFB) Derived from Waste Engine Oil
i. The BSFC of tested fuel blends was noticeably increased in comparison to diesel and
BTE was decreased with increase in the CFB proportion. Among the fuel blends tested
CFB15 has shown negligible difference of BSFC (2.58%) and BTE (1.51%) in
comparison to petroleum diesel.
ii. CO and HC emissions of CFB15, CFB25, CFB35, CFB45 and CFB55 were found
significantly lower than those of petroleum diesel. The smoke density of tested fuel
blends was decreased in comparison to diesel fuel.
iii. Overall NOx emissions were increased with increase in the CFB concentrations. CBF15
has shown less NOx emissions in comparison to all the fuel blends tested. It was observed
that NOx emission value of CFB15 was closer to that of petroleum diesel.
iv. Based on the engine performance and lower emission characteristics, the fuel blend
CFB15 can be effectively used as an alternative fuel in compression ignition diesel
engines.
v. This work was the first demonstration of combine blending and converting of waste
engine and waste cooking oils as an alternative fuel for diesel engines. This will reduce
hazardous waste oil disposal problems, minimize environmental issues and boost the
economy of the country Pakistan by minimizing its dependence on foreign origin crude
oil reserves for mineral diesel fuel.
Biodiesel Like Fuel (BLF) Blends Derived from Waste Transformer Oil
i. The results of FTIR analysis have confirmed that BLF fuel has the similar characteristics
to that of petroleum diesel showing saturated alkane structures.
178
ii. It is observed that fuel obtained from the mixture of transesterified waste transformer oil
(TWTO) and waste canola oil methyl esters (WCOME) have the fuel properties
comparable to petroleum diesel and were found within the international specified
standard (EN 14214 and ASTM 6751-03) limits of biodiesel fuel.
iii. EGT and BSFC of BLF fuel blends as compared to petroleum diesel was found to
increase by 1.68% to 4.33% and 2.48% to 6.45%, respectively, at maximum load
conditions, however, BTE decreased 1.99% to 4.91% with increase in BLF
concentrations in the fuel blend. BLF15 has lower fuel consumption value (632.02 g/kW
h), higher BTE (29.91%) and lower EGT (224 oC at minimum engine load) as compared
to BLF20 and BLF25 fuel blends.
iv. The HC and CO emissions of diesel engine with BLF fuel blends were observed to
reduce by 10.92% to 31.17% and 3.80 to 6.32%, respectively, as compared to those of
diesel fuel. The smoke density was reduced by 1.39% to 5.21% whereas NOx emissions
were found to increase by 3.16% to 7.78% in relation to diesel fuel.
v. Minimum decrease of CO, HC, smoke value and minimum increase of NOx emissions
was found with BLF15. BSFC, EGT and BTE values of BLF15 fuel blend are closer to
those of petroleum diesel. It is therefore, suggested that this fuel blend may be used in
diesel engines without any engine modifications.
vi. Pakistani waste transformer and waste canola oils have been successfully converted into
fuel which might boost the country’s economy by saving its crude oil import bills and
also the outcome of this research work was to minimize the environmental problems
arising from the waste oil disposals.
179
Fuel Mixtures Derived from Waste Tyre Pyrolysis Oil
i. All the physicochemical properties of the FMWO fuel blends were found to be within the
international fuel standards of diesel (ASTM 975) and biodiesel (ASTM 6751 &
EN14214).
ii. The BSFC of FMWO fuel blends was decreased with increase in the engine load. In
comparison to diesel fuel, the BSFC of all the fuel blends was marginally increased.
FMWO10 has shown lowest BSFC (344.63g/kWh) and FMWO50 has shown highest
BSFC (367.64 g/kWh) among all the fuel blends analyzed.
iii. All the tested fuel blends exhibited lower BTE value than diesel, however, FMWO10 has
shown higher BTE (29.24%) than other FMWO fuel blends.
iv. Overall, 3.12-15.62% and 16.5-33.2% lower CO and HC emissions were observed for
FMWO fuel blends in comparison to diesel fuel. Decrease in smoke emissions was
noticed to be 1.83 - 4.5% for FMWO blends in comparison to that of diesel.
v. The overall NOx emissions were increased as the engine load was increased; however,
FMWO10 has shown less NOx emissions among all the FMWO fuel blends.
vi. The engine was successfully operated with all FMWO blends without engine failure but
the performance of FMWO10 was found outclass among all the fuel blends.
Fuel Blends Derived from Waste Cooking Oil Biodiesel (WCOB)
i. All the fuel properties of the biodiesel blends (B10, B15 and B20) obtained from waste
cooking oil were found within the specified international standard (ASTM 6751 &
EN14214) limits.
ii. The fuel properties of blends B10 and B15 having fewer concentration of biodiesel were
comparable to those with petroleum diesel.
180
iii. BSFC of the diesel engine when operated with B10, B15 and B20 blended fuels as
compared to diesel fuel was observed to increase 2.96%, 4.73% and 7.85%, respectively,
and EGT was found to increase 4.43%, 5.11% and 6.4%, respectively. However, BTE
was found to decrease by 1.52-3.58% with increase in the concentration of biodiesel in
the fuel blends.
iv. B10 has shown lower BSFC (279.40 g/kW h) and EGT (302 o C) as well as BTE value
closer to that of petroleum diesel among all the blends of biodiesel examined.
v. On the basis of lower fuel consumption, closer fuel properties and BTE value of B10 to
those of petroleum diesel, it is very much obvious that B10 biodiesel fuel blend can be
used as an alternative fuel in diesel engines without any engine modification.
Future Work Recommendations
Following are the suggestions for future studies in relation to the work reported in this thesis:
i). Computer modeling may be carried out to get better results while setting the engine
parameters for waste oils derived biodiesel-diesel blends.
ii). Engine fueled with waste oils derived biodiesel blends may be operated with different
nozzle oppening pressures and injection timings.
iii). Waste oils derived biodiesels may be tested in automotive engines.
iv). For the better understandings of the results, detailed analysis for reactive conditions could
be carried out.
v). Further studies on unexplored feed stocks may be carried out to prepare biodiesels.
181
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191
APPENDIX-I
Author’s Academic and Research Profile
Personal Information
Name: Muhammad Qasim
Father’s Name: Mehar Gul
CNIC No.: 43104-1650224-3
Religion: Islam
Native Town: Kashmore
Domicile: Kashmore
Research Scholar: Institute of Chemical Sciences, Bahauddin Zakariya
University, Multan, Pakistan
Mailing address: H. No. 06, Hans Street, New Shalimar Colony, Bosan
Road, Near Dera Hans Chaowk, Multan.
E-mail: [email protected]
Research Publications
1. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2016). Physico-
Chemical Characteristics of Pakistani used engine oils. J. Petr. Technol. Altrn. Fuels, 07,
(2016) 13 –17.
2. Muhammad Qasim and Mushtaque Ali Jakhrani (2017). Physicochemical and elemental
contamination assessment in groundwater samples of Khairpur Mir's, Pakistan. Human
and Ecological Risk Assessment: An International Journal, 1(10), 7415.
DOI: 10.1080/10807039.2016.1277415 (Impact Factor. 1.306).
3. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2017). Combustion,
Performance, and Emission Evaluation of a Diesel Engine with Biodiesel Like Fuel
Blends Derived from a Mixture of PakistaniWaste Canola and Waste Transformer Oils
Energies, 10, 1023; doi:10.3390/en10071023. (Impact Factor 2.262)
4. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2017). Preparation,
Characterization and Engine Performance of Biodiesel Fuel Derived from Waste Cooking
Oil and its Blends. Int. J. Sciences 6(03), 113-118.
192
5. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2017). Comparative
Assessment of Thermo Chemical Properties of Different Consumable Automobile Oils in
Respect of their Environmental Friendly Use Int. J. Sciences 6(04), 70-79.
6. Surraya Manzoor, Mazhar Abbas, Tariq Mahmood Ansari, Muhammad Qasim and
Zaibullah Khan (2016). Preparation and Characterization of Biodiesels Produced from
Waste and Pure Hydrogenated Cooking Oils of Various Brands Manufactured in
Pakistan. Int.J. Advnc. Research & Management, 1(7), 192 – 199.
7. Mushtaque Ali, Farkhanda Zaman Dayo, Muhammad Qasim, Shahid Ali and Ashfaque
Ahmed (2017). Elemental assessment in economically important Cirrhinus Mrigala and
Labeo Rohita fish species captured from indus river at Guddu Barrage, Sindh, Pakistan.
Int. J. Sciences 6(08), 117-125. DOI: 10.18483/ijSci.1400
8. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2017). Experimental
investigations on a diesel engine operated with fuel blends derived from a mixture of
Pakistani waste tyre oil and waste soybean oil biodiesel" Environmental Science and
Pollution Research https://doi.org/10.1007/s11356-017-0380-9 (Impact Factor 2.76).
Conferences/Seminars/Workshops Attended
1. 6th International and 16th National Chemistry Conference, ICS, BZU, Multan. April
06-08, 2006.
2. 1st International Conference on Energy & Environment, Quaid-e Awam, University of
Engineering Science &Technology Nawab Shah, Sindh.
February 26– 28, 2009.
3. 2nd International Conference on Environmental and Computer Science, Dubai, UAE.
December 28– 30, 2009.
4. 12th International and 24th National Chemistry Conference, BZU, Multan.
October 28 – 30, 2013.
193
APPENDIX-II
Ph.D work research publications
Following papers were published based upon the work done in this thesis:
1. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2016). Physico-
Chemical Characteristics of Pakistani used engine oils. J. Petr. Technol. Altrn. Fuels, 07,
(2016) 13 –17.
2. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2017). Combustion,
Performance, and Emission Evaluation of a Diesel Engine with Biodiesel Like Fuel
Blends Derived from a Mixture of PakistaniWaste Canola and Waste Transformer Oils
Energies, 10, 1023; doi:10.3390/en10071023 (Impact Factor 2.262).
3. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2017). Preparation,
Characterization and Engine Performance of Biodiesel Fuel Derived from Waste Cooking
Oil and its Blends. Int. J. Sciences 6(03), 113-118.
4. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2017). Comparative
Assessment of Thermo Chemical Properties of Different Consumable Automobile Oils in
Respect of their Environmental Friendly Use Int. J. Sciences 6(04), 70-79.
5. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2017). Experimental
investigations on a diesel engine operated with fuel blends derived from a mixture of
Pakistani waste tyre oil and waste soybean oil biodiesel" Environmental Science and
Pollution Research https://doi.org/10.1007/s11356-017-0380-9 (Impact Factor 2.76).
6. Muhammad Qasim, Tariq Mahmood Ansari and Mazhar Hussain (2017). Emissions
and Performance Characteristics of a Diesel Engine Operated with Fuel Blends Obtained
from a Mixture of Pretreated Waste Engine Oil and Waste Vegetable Oil Methyl Esters"
Environmental Progress and sustainable energy (accepted, manuscript ID EP-17-263).
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