CBB 4023 PLANT DESIGN II DESIGN OF MALEIC ANHYDRIDE

CBB 4023

PLANT DESIGN II

DESIGN OF

MALEIC ANHYDRIDE PRODUCTION PLANT

GROUP 6

AMIRAH RAIHANA BINTI HARIS FADZILAH 11885

MARYAM FARZANAH BINTI MOHD FAUZI 11971

MOHAMMAD ILHAM BIN MAT HUSSIN 12004

MOHAMMAD KHAIRULANAM BIN AZEMAN 12005

NUR SYAFIQAH BINTI ABDUL MANAN 12148

CHEMICAL ENGINEERING DEPARTMENT

UNIVERSITI TEKNOLOGI PETRONAS

SEPTEMBER 2012

1

CERTIFICATION OF APPROVAL

CBB 4023

PLANT DESIGN II

DESIGN OF

MALEIC ANHYDRIDE PRODUCTION PLANT

GROUP 6

AMIRAH RAIHANA BINTI HARIS FADZILAH 11885

MARYAM FARZANAH BINTI MOHD FAUZI 11971

MOHAMMAD ILHAM BIN MAT HUSSIN 12004

MOHAMMAD KHAIRULANAM BIN AZEMAN 12005

NUR SYAFIQAH BINTI ABDUL MANAN 12148

APPROVED BY:

________________________________________

DR. RISZA BINTI RUSLI (Group Supervisor)

DATE: 20TH

SEPTEMBER 2012

CHEMICAL ENGINEERING DEPARTMENT

UNIVERSITI TEKNOLOGI PETRONAS

SEPTEMBER 2012

2

EXECUTIVE SUMMARY

Maleic anhydride is a versatile chemical intermediate used to make unsaturated polyester

resins, lube oil additives, alkyd resins, and variety of other products. Maleic anhydride is

frequently shortened to MAN. In order to produce MAN, the process involved is by the

oxidation of benzene or other aromatic compounds. In this case, we would use the normal

butane (n-butane) as the main feed. Regarding to this process, it will be further explain in the

next chapter as well as the process route that has been chosen in this project.

The main objective of this project is to develop a Maleic Anhydride production plant. The

development of plant should consider all the relevant criteria required in order to make the

most optimize production plant.

Throughout this project, overall document emphasized on the details of the project

background, market survey, site feasibility study, conceptual process design, process control,

safety and loss prevention, waste treatment facility as well as economic evaluation. Location

chosen for MAN production plant is at Kidurong, Sarawak. This is due to the availability of

raw materials, utilities and transportation.

In United States, MAN production rate is estimated to be about 250,000tonnes/annum.

According to the demand, the quantity of MAN is about 223,000tonnes/annum.Thus, the

proposed plant design will be justified based on the economic potential of the process, by

comparing the price of MAN and price of raw materials needed. Hence, overall process

description of this project will be further explained in the next chapters.

3

ACKNOWLEDGEMENT

Alhamdulillah, praised to God for giving us an opportunity to complete this Plant Design

Project I and II courses after struggling with all the problems and challenges in completing

design project for the past several months.

There were about fourteen (14) weeks have been given to us in completing the design project

in Plant Design Project II (CBB4023) course under the supervision of our keen supervisor,

Dr. RiszaRusli. We as the member of this group would like to pass our highest gratitude to

Dr. RiszaRusli for all his guidance and continuous supports throughout the semester. He has

been a very supportive supervisor and willing to share his knowledge, in order to ensure that

we could learn and understand every single thing in this project. Our gratitude is also

extended to PDP 2 coordinator, Dr. Rajashekar and DrMurniMelati for their effort in

arranging and planning the course structures so that all will be run smoothly.

Last but not least, our appreciation is given to our beloved group mates, course mates and

also friends, thanks for all supports and motivations, which helps us a lot to make sure that

this project ended successfully. Not to forget to those who directly or indirectly involved in

giving us the opportunity to learn and work as a team while designing our first plant project.

4

TABLE OF CONTENTS

CERTIFICATION OF APPROVAL .................................................................................................................. 1

EXECUTIVE SUMMARY .................................................................................................................................. 2

ACKNOWLEDGEMENT ................................................................................................................................... 3

TABLE OF CONTENTS ..................................................................................................................................... 4

LIST OF FIGURES .............................................................................................................................................. 8

LIST OF TABLES ................................................................................................................................................ 9

CHAPTER 1: INTRODUCTION...................................................................................................................... 10

1.1 PROJECT BACKGROUND ...................................................................................................................... 10

1.2 PROBLEM STATEMENT ......................................................................................................................... 10

1.3 OBJECTIVES ............................................................................................................................................ 10

1.4 SCOPE OF PROJECT ................................................................................................................................ 11

CHAPTER 2: LITERATURE REVIEW ......................................................................................................... 12

2.1 BACKGROUND OF PRODUCT ............................................................................................................... 12

2.1.1 Product Overview: Maleic anhydride (MAN) ................................................................................. 12

2.1.2 History of MAN Production(Timothy R. Felthouse, 2001) ............................................................. 12

2.2 AVAILABLE & FEASIBLE PROCESS ROUTES TO MAN PRODUCTION ......................................... 14

2.2.1 Benzene partial oxidation to MAN (AP-42, CH 6.14: Maleic Anhydride) ...................................... 14

2.2.2 N-butane partial oxidation to MAN ................................................................................................ 15

2.2.3 MAN fromphthalic anhydride recovery process ............................................................................. 15

2.3 SCREENING AND SELECTION OF PROCESS ROUTES ...................................................................... 16

2.4 PHYSICAL AND CHEMICAL PROPERTIES ......................................................................................... 17

2.5 COST DATA .............................................................................................................................................. 17

2.6 SITE FEASIBILITY STUDY ..................................................................................................................... 19

2.6.1 Introduction .................................................................................................................................... 19

2.6.2 Selection Criteria ............................................................................................................................ 19

2.6.3 Summary of site Characteristic in Each Location .......................................................................... 20

2.6.4 Site Evaluation ................................................................................................................................ 21

2.7 POTENTIAL HAZARDS .......................................................................................................................... 23

2.7.1 Previous Accident On Similar Plant ............................................................................................... 23

2.7.2 Potential Hazards and Control Measures ...................................................................................... 24

2.7.3 Material Safety Data Sheet (MSDS) & Hazard .............................................................................. 26

CHAPTER 3: CONCEPTUAL PROCESS DESIGN AND SYNTHESIS ..................................................... 30

3.1 LEVEL I: PROCESS OPERATING MODE .............................................................................................. 30

5

3.2 LEVEL II: INPUT-OUTPUT STRUCTURE ............................................................................................. 31

3.3 LEVEL III: REACTOR DESIGN AND REACTOR NETWORK SYNTHESIS ....................................... 32

3.3.1 Reactor Conversion Selections ....................................................................................................... 33

3.3.2 Preliminary Reactor Mass Balance ................................................................................................ 34

3.3.3 Reactor Type Selection ................................................................................................................... 36

3.4 LEVEL IV: SEPARATION SYSTEM SYNTHESIS ................................................................................. 38

3.4.1 First Process Route ......................................................................................................................... 39

3.4.2 Second Process Route ..................................................................................................................... 40

3.4.3 Process Route Selection .................................................................................................................. 41

3.5 LEVEL V: HEAT INTEGRATION ........................................................................................................... 41

3.5.1 Introduction to Pinch Analysis........................................................................................................ 41

3.5.2 SPRINT Software ............................................................................................................................ 42

3.5.3 Stream Data Extraction .................................................................................................................. 42

3.5.4 Minimum Temperature Difference .................................................................................................. 43

3.5.5 Maximum Process Heat Recovery .................................................................................................. 43

3.5.6 Heat Exchanger Network ................................................................................................................ 46

3.5.7 Energy-Saving Evaluation .............................................................................................................. 47

CHAPTER 4: INSTRUMENTATION AND CONTROL ............................................................................... 48

4.1 INTRODUCTION ...................................................................................................................................... 48

4.2 DESIGN OF PLANT WIDE CONTROL SYSTEM ................................................................................... 48

4.2.1 Procedures ...................................................................................................................................... 48

4.2.2 Drier Control System ...................................................................................................................... 49

4.2.3 Deisobutanizer Control System....................................................................................................... 49

4.2.4 Reactor Control System .................................................................................................................. 50

4.2.5 Heat Exchanger Control System ..................................................................................................... 52

4.2.6 Absorber Control System ................................................................................................................ 53

4.2.7 Stripper Distillation Column Control System ................................................................................. 54

CHAPTER 5: SAFETY AND LOSS PREVENTION ..................................................................................... 56

5.1 HAZARD AND OPERABILITY STUDIES (HAZOP) ............................................................................. 56

5.1.1 Introduction to HAZOP .................................................................................................................. 56

5.1.2 Study Nodes Selection ..................................................................................................................... 56

5.1.3 HAZOP Analysis ............................................................................................................................. 57

5.2 PLANT LAYOUT ...................................................................................................................................... 65

5.2.1 Site Layout ...................................................................................................................................... 65

5.2.2 Non-Process Area ........................................................................................................................... 65

5.2.3 Process Area ................................................................................................................................... 66

5.2.4 Assembly point ................................................................................................................................ 68

5.2.5 Emergency Exit ............................................................................................................................... 69

5.3 PLANT LAYOUT CONSIDERATION FACTORS .................................................................................. 69

6

CHAPTER 6: WASTE TREATMENT ............................................................................................................ 72

6.1 INTRODUCTION ...................................................................................................................................... 72

6.2 WASTE MINIMIZATION ......................................................................................................................... 73

6.3 WASTE AUDIT ......................................................................................................................................... 73

6.4 EFFLUENT DISCHARGE STANDARD AND REQUIREMENTS ......................................................... 74

6.4.1 Purpose of Effluent Standards ........................................................................................................ 74

6.4.2 Liquid waste .................................................................................................................................... 75

6.4.3 Gaseous Waste ................................................................................................................................ 76

6.4.4 Solid waste ...................................................................................................................................... 76

6.5 TREATMENT STRATEGY ...................................................................................................................... 76

6.6 SCREENING PROCESS ............................................................................................................................ 80

6.6.1 Aerated Grit Removal ..................................................................................................................... 80

6.6.2 pH Stabilizer ................................................................................................................................... 80

6.6.3 Equalization Tank ........................................................................................................................... 80

6.6.4 Coagulation Tank ........................................................................................................................... 81

6.6.5 Clarifier .......................................................................................................................................... 81

6.6.6 Sludge Dewatering .......................................................................................................................... 81

6.6.7 Mechanical Sludge Thickener ......................................................................................................... 81

6.6.8 Sludge Storage ................................................................................................................................ 81

6.6.9 Disinfection ..................................................................................................................................... 82

6.6.10 Biopond ...................................................................................................................................... 82

6.7 GAS TREATMENT ................................................................................................................................... 82

6.8 SOLID HANDLING TREATMENT .......................................................................................................... 85

6.9 SCHEDULED WASTE .............................................................................................................................. 86

CHAPTER 7: PROJECT ECONOMICS AND COST ESTIMATION ......................................................... 87

7.1 INTRODUCTION ...................................................................................................................................... 87

7.1.1 Capital Investment .......................................................................................................................... 87

7.1.2 Total Equipment Cost (TEC) .......................................................................................................... 88

7.1.3 Fixed Capital Investment ................................................................................................................ 88

7.1.4 Estimation of Total Operating Cost ................................................................................................ 89

7.1.5 Gross Profit .................................................................................................................................... 89

7.2 PROFITABILITY ANALYSIS .................................................................................................................. 90

7.2.1 Start-up Period ............................................................................................................................... 90

7.2.2 Depreciation ................................................................................................................................... 90

7.2.3 Cash Flow Estimation ..................................................................................................................... 91

7.2.4 Net Present Worth ........................................................................................................................... 92

7.2.5 Internal Rate of return .................................................................................................................... 92

7.2.6 Rate of Return (ROR) Estimation ................................................................................................... 92

7.2.7 Net Present Value or Worth (NPV) Estimation............................................................................... 92

7

7.2.8 Pay Back Time ................................................................................................................................ 93

7.3 DISCUSSIONS .......................................................................................................................................... 93

CHAPTER 8: CONCLUSION & RECOMMENDATION ............................................................................. 94

8.1 CONCLUSION .......................................................................................................................................... 94

8.2 RECOMMENDATION .............................................................................................................................. 95

REFERENCES ................................................................................................................................................... 96

APPENDICES ..................................................................................................................................................... 98

8

LIST OF FIGURES

FIGURE 1: THE MAIN PROCESS TECHNOLOGY FROM SCIENTIFIC DESIGN ...................... 14

FIGURE 2: REACTIONS FOR PARTIAL OXIDATION OF N-BUTANE TO MAN ...................... 15

FIGURE 3: GLOBAL DEMAND OF MAN ACCORDING TO REGION(MALEIC ANHYDRIDE . 18

FIGURE 4: PRODUCTION CAPACITY OF MAN ACCORDING TO REGION, 2000 .................. 18

FIGURE 5: KIDURONG INDUSTRIAL AREA ........................................................................... 23

FIGURE 6: SCHEMATIC PROCESS OF AMMONIA .................................................................. 31

FIGURE 7: HEURISTIC METHOD: ONION MODEL ................................................................. 38

FIGURE 8: FIRST PROCESS ROUTE ........................................................................................ 40

FIGURE 9: SECOND PROCESS ROUTE .................................................................................... 41

FIGURE 10: COMPOSITE CURVE FOR MAXIMUM HEAT RECOVERY: ................................. 44

FIGURE 11: PROBLEM TABLE ALGORITHM BY SPRINT SOFTWARE .................................. 45

FIGURE 12: HEAT EXCHANGER NETWORK .......................................................................... 46

FIGURE 13: SELECTED STUDY NODES CONNECTED TO REACTOR .................................... 57

FIGURE 14: ISOBUTANE STORAGE TANK ............................................................................. 77

FIGURE 15: BLOCK DIAGRAM OF WASTEWATER TREATMENT PLANT ............................. 78

FIGURE 16: FLOW SHEET OF WASTEWATER TREATMENT PLANT..................................... 79

FIGURE 17: NITROGEN SEPARATOR ..................................................................................... 84

FIGURE 18: WASTE OF STREAM 18 (S18) .............................................................................. 85

FIGURE 19: CASH FLOW DIAGRAM ....................................................................................... 91

FIGURE 20: PAYBACK TIME ................................................................................................... 93

9

LIST OF TABLES

TABLE 1: WORLD MAN CAPACITY BY REACTOR TYPE (MAN WORLD SURVEY, 1992) ... 13

TABLE 2: CONTRIBUTING FACTORS TO OPERABILITY AND ECONOMY ASPECTS .......... 20

TABLE 3: WEIGHTAGE CRITERIA IN DECIDING SITE LOCATION ...................................... 21

TABLE 4: WEIGHTAGE TABLE ON SITES .............................................................................. 22

TABLE 5: ANALYSIS OF POTENTIAL HAZARDS ................................................................... 25

TABLE 6: HAZARD ANALYSIS ............................................................................................... 26

TABLE 7: GUIDELINES FOR BATCH AND CONTINUOUS PROCESS ..................................... 30

TABLE 8: PRODUCTION OF MALEIC ANHYDRIDE FROM N-BUTANE ................................. 33

TABLE 9: PRELIMINARY REACTOR MASS BALANCE .......................................................... 34

TABLE 10: MASS BALANCE WITH RECYCLE ........................................................................ 35

TABLE 11: ADVANTAGES AND DISADVANTAGES OF PACKED BED REACTOR (SMITH) . 36

TABLE 12: ADVANTAGES AND DISADVANTAGES OF FLUIDIZED BED REACTOR ........... 36

TABLE 13: STREAM DATA EXTRACTED ............................................................................... 42

TABLE 14: OPTIMUM TMIN IN DIFFERENT INDUSTRIES (PINCH ANALYSIS).................... 43

TABLE 15: UTILITIES REQUIRED BEFORE HEAT INTEGRATION ........................................ 44

TABLE 16: UTILITIES REQUIRED AFTER HEAT INTEGRATION .......................................... 45

TABLE 17: COMPARISON OF UTILITY REQUIREMENT BEFORE AND AFTER HI ............... 47

TABLE 18: DRIER CONTROL SYSTEM DETAILS ................................................................... 49

TABLE 19 : DEISOBUTANIZER CONTROL SYSTEM DETAILS .............................................. 50

TABLE 20: REACTOR CONTROL SYSTEM DETAILS ............................................................. 52

TABLE 21: COOLER CONTROL SYSTEM DETAILS ................................................................ 53

TABLE 22: HEAT EXCHANGER CONTROL SYSTEM DETAILS ............................................. 53

TABLE 23: GAS ABSORBER, C-301 CONTROL SYSTEM DETAILS ........................................ 54

TABLE 24: DISTILLATION COLUMN CONTROL SYSTEM ..................................................... 55

TABLE 25: STUDY NODES IN HAZOP ANALYSIS .................................................................. 56

TABLE 26: STUDY NODE #1 .................................................................................................... 58

TABLE 27: STUDY NODE #2 .................................................................................................... 60

TABLE 28: STUDY NODE #3 .................................................................................................... 62

TABLE 29: RECOMMENDED MINIMUM CLEARANCE ........................................................... 70

TABLE 30: WASTE STREAMS PROPERTIES ........................................................................... 74

TABLE 31: ENVIRONMENTAL QUALITY (EXTRACT) ........................................................... 75

TABLE 32: PLANT WASTEWATER AND STANDARD B VALUES OF EQA ............................ 76

TABLE 33: METHOD OF REMOVAL ACCORDING TO WASTE COMPONENT ....................... 76

TABLE 34: SUMMARY OF LIMITATIONS FOR THE GASEOUS TREATMENT STRATEGY ... 82

TABLE 35: DISPOSAL METHODS OF SOLID WASTE ............................................................. 85

TABLE 36: TOTAL EQUIPMENT COST ................................................................................... 88

TABLE 37: CAPITAL INVESTMENT FOR START-UP PERIOD ................................................ 90

TABLE 38: CUMULATIVE CASH FLOW .................................................................................. 92

10

CHAPTER 1: INTRODUCTION

1.1 PROJECT BACKGROUND

The final year design project team has been assigned to design a Maleic Anhydride

production plant using mixed butane as the raw material. For this semester, the team needs to

incorporate safety aspects, site selection, conceptual design, material and energy balance,

heat integration and preliminary economic evaluation in the early design of the plant. Each

team is also assigned a lecturer from the Chemical Department as a supervisor to guide the

students in designing the plant.

1.2 PROBLEM STATEMENT

Maleic anhydride (MAN) is used in the production of unsaturated polyester resins. These

laminating resins have a high structural strength and good dielectric properties. These

characteristics makes maleic anhydride eligible for a variety of applications in automobile

bodies, molded boats, building panels, , chemical storage tanks, lightweight pipe, machinery

housings, furniture, luggage, and bathtubs. Maleic anhydride is also used to produce other

chemicals including fumaric acid, agricultural chemicals, alkyd resins, lubricants,

copolymers, plastics, and succinic acid.

The main feed stocks for MAN industry are benzene and normal butane. However, due to its

increasing cost of benzene and chemical hazard of benzene, the industry turned to butane as

the main feed stock because of its fewer hazards compared to benzene, low cost and abundant

source availability.

The team is assigned the task of designing a Maleic Anhydride production plant using a pre-

specified composition of mixed butane as the raw material. The capacity of the plant must be

determined based on the demand and worldwide market for Maleic Anhydride.

1.3 OBJECTIVES

The objective of this project is to develop a Maleic Anhydride production plant. The plant

must be cost-effective, considers all of the desired criteria in addition to dealing with relevant

issues. The team needs to recommend the best possible design, which will ultimately

convince panel of juries to verify the new plant. The objectives of this design project include

the following:

11

To integrate chemical engineering skills and knowledge in a detailed design of a

chemical plant.

To apply appropriate design codes in a detailed design work

To present a piping and instrumentation diagram (P&ID) and control strategy

packages

To perform detailed economic evaluation of the proposed chemical plant

To generate cost effective process options while maintaining operability, safety

and environment friendliness of the design.

1.4 SCOPE OF PROJECT

The scopes of work for FYDP II are as follows:

Making the necessary decisions, judgements and assumptions in design problems.

Performing the instrumentation and control study

Performing the process design of the major process units.

Performing the mechanical design of the major process units.

Performing the economic evaluation including capital cost estimation and

manufacturing cost estimation.

Considering the environmental and safety issues related to the plant. Material

safety data sheet (MSDS) for all the chemicals involved must be part of the safety

and environmental discussion.

Utilising the blend of hand calculations, spreadsheets, mathematical computer

packages, and process simulators to design a process

Preparing the group and individual reports as per standard format and conducting

the oral presentations.

12

CHAPTER 2: LITERATURE REVIEW

2.1 BACKGROUND OF PRODUCT

2.1.1 Product Overview: Maleic anhydride (MAN)

Maleic anhydride is a versatile molecule that is used in many applications which requires a

number of functionalities and properties (Timothy R. Felthouse, 2001). It is considered an

excellent joining and cross linking agent due to its three active sites (one double bond and

two carboxyl groups). Besides that, due to its cross linking abilities, it is widely used in the

manufacturing of unsaturated polyester resins. Maleic Anhydride is also one of the important

intermediate in the fine chemical industry, mainly in the manufacturing of agricultural

chemicals and additives for lubricating oil. In addition, it also serves as a component for

several copolymers in the polymer sectors (Lohbeck, Haferkorn, Fuhrmann, & Fedtke, 2005).

In 1928, Diels and Alder worked on a reaction between Maleic Anhydride and 1,4-butadiene

and the work was later awarded the Nobel prize in 1950. The starting of the usage of Maleic

Anhydride in the pesticide and pharmaceutical industries was because of the studied reaction.

Several examples of the specialty chemicals that can be prepared from Maleic Anhydride

includes tartaric acid, diethyl and dimethyl succinate, malic acid, glyoxylic acid,

diisobutylhexahydrophthalate (DIBE), methyl tetrahydrophthalic anhydride esters and

dodecene succinic anhydride. (Lohbeck, Haferkorn, Fuhrmann, & Fedtke, 2005)

2.1.2 History of MAN Production(Timothy R. Felthouse, 2001)

Maleic anhydride was initially commercialized in the early 1930s through the selective

oxidation of benzene. The usage of benzene as the feed for the production of maleic

anhydride was dominant until 1980s. Several processes were introduced with the common

ones that were from Scientific Design. By then, there were also small amount of maleic acid

being produced as by-product in the production of phtalic anhydride that can be oxidised into

maleic anhydride.

However, the usage of benzene started to change and was replaced by n-butane in 1974

because of its toxic effects and economic aspects. The recognition of benzene as hazardous

material and deemed carcinogen substance with the rapid increase in the benzene price

opened up the search for alternative process technology specifically in the

13

United States. Later, the first commercial production of maleic anhydride from butane was

established at Monsato’s J. F. Queeny plant in the year 1974.

After 1980s, the United States maleic anhydride industries underwent a conversion of

feedstock from benzene to butane. But, during the early years, the conversion to butane as

feedstock had its limitation whereby the early butane-based catalyst were not active and

selective enough for a better conversion of benzene-based plant without a significant loss of

capacity production.

However, further enhanced catalyst was developed by Monsanto, Denka, and Halcon which

led to the world’s first butane-to-maleic anhydride plant which was started up by Monsanto in

1983. The plant incorporated an energy efficient solvent-based product collection and

refining system. It was then the largest maleic anhydride production facility and later it

undergone debottlenecking project from a capacity of 59,000 tons per year to 105,000 tons

per year in 1999.

By mid-1980s, United States 100% of maleic anhydride production were using butane as

feedstock due to advances in catalyst technology, increased regulatory pressures, and

continuing cost advantages of butane over benzene.

Meanwhile, Europe has also converted from benzene-based to butane-based maleic anhydride

technology starting from the construction of new butane based facilities by CONDEA-

Hunstman, Pantochim and Lonza. The growth in the industry turned to the butane-to-maleic

anhydride route, usually at the expense of benzene-based production.

Table below shows the worldwide maleic production capacity broken down into fixed-bed

benzene, fixed-bed butane, fluidized-bed butane, andphthalic anhydride (PA) co-product.

TABLE 1: WORLD MAN CAPACITY BY REACTOR TYPE (MAN WORLD SURVEY, 1992)

1993 Actual 2000 Actual

Reactor (Feed) Kiloton / year, % Kiloton / year, %

Fixed Bed (butane) 369 43.0 704 51.8

Fixed Bed (benzene) 325 37.9 388 28.5

Fluid Bed (butane) 127 14.8 217 16.0

Fixed Bed (PAcoproduct) 37 4.3 50 3.7

Total 858 100.0 1359 100.0

14

It can be seen from the table that both fixed-bed and fluidized-bed butane routeshave

increased dramatically with the fixed-bed route adding 336 kiloton/year capacity compared to

90 kiloton/year for the fluid-bed process. Only a few newer benzene-based fixed-bed

processes have been built with a difference of 63 kiloton/year since the early1980s and the

reason it was built was due to limited resource of butane.

2.2 AVAILABLE & FEASIBLE PROCESS ROUTES TO MAN PRODUCTION

Generally, there are 3 routes that can be considered for the commercial production of MAN.

The 3 routes are given below together with their chemical reactions:

2.2.1 Benzene partial oxidation to MAN (AP-42, CH 6.14: Maleic Anhydride)

FIGURE 1: THE MAIN PROCESS TECHNOLOGY FROM SCIENTIFIC DESIGN

Vaporized benzene and air are mixed and heated before entering the tubular reactor. Inside

the reactor, the benzene/air mixture is reacted in the presence of a catalyst that contains

approximately 70 percent vanadium pentoxide (V2O5), with usually 25-30% molybdenum

trioxide (MoO3), forming a vapor of MA, water, and carbon dioxide. The vapor, which may

also contain oxygen, nitrogen, carbon monoxide, benzene, maleic acid, formaldehyde, formic

acid, and other compounds from side reactions, leaves the reactor and is cooled and partially

condensed so that about 40 percent of the MA is recovered in a crude liquid state.

The effluent is then passed through a separator that directs the liquid to storage and the

remaining vapor to the product recovery absorber. The absorber contacts the vapor with

water, producing a liquid of about 40% maleic acid. The 40% mixture is converted to MA,

usually by azeotropic distillation with xylene. Some processes may use a double-effect

vacuum evaporator at this point. The effluent then flows to the xylene stripping column

where the xylene is extracted. This MA is then combined in storage with that from the

separator. Themolten product is aged to allow color-forming impurities to polymerize. These

are then removed in a fractionation column, leaving the finished product.

15

2.2.2 N-butane partial oxidation to MAN

FIGURE 2: REACTIONS FOR PARTIAL OXIDATION OF N-BUTANE TO MAN

Several process technologies for butane-to-maleic anhydride was designed including

Huntsman process, Scientific Design process, Technobell Limited process, Alusuisse maleic

anhydride (ALMA) process, and Du Pont moving bed recycle based process.

Butane and compressed air are mixed and fed adiabatic reactor, where butane reacts with

oxygen to form maleic anhydride. The reaction is exothermic, therefore either a fluidized bed

reactor or a packed bed reactor with heat removal to stay close to isothermal. The reactor

effluent is cooled and sent to packed bed absorber, where it is contacted with water to remove

the light gases and all of the maleic anhydride reacts to form maleic acid. The vapor effluent,

which consists of non-condensable must be sent to an after-burner to remove any carbon

monoxide prior to venting to the atmosphere. The liquid effluent is then cooled and flashed at

101 kPa and 120°C. The vapour effluent after flashed is sent to waste treatment where else

the liquid effluent, is sent to another reactor where maleic acid is broken down to maleic

anhydride and water. The reactor effluent is then sent to distillation column where maleic

anhydride and water are separated. The distillate from the distillation column is sent to waste

treatment (Production of Maleic Anhydride).

2.2.3 MAN fromphthalic anhydride recovery process (MAN as a byproduct of the

production of phthalic anhydride)

C8H10 + 7.5O2 C4H2O3 + 4H20 +4CO2∆H = -2518.5 kJ/mole

16

The process technology involved in this process route includes LURGI - BASF Phthalic

Anhydride Process and Technobell Limited Process.

Hot air and vaporized o-xylene are mixed and sent to a packed bed reactor. Most of the o-

xylene reacts to form phthalic anhydride, but some complete combustion of o-xylene occurs

and some maleic anhydride is formed. The reactor temperature is controlled by a molten salt

loop. The reactor effluent enters a complex series of devices known as switch condensers.

The feed to the switch condensers may be no higher than 180°C; hence, the reactor effluent

must be cooled. The net result of the switch condensers is that all light gases and water leave

through the top while small amounts of both anhydrides, and the phthalic anhydride and

maleic anhydride leave in the bottom. The bottom stream is then purified to obtain maleic

anhydride. (Production of Phthalate Anhydride from O-xylene).

2.3 SCREENING AND SELECTION OF PROCESS ROUTES

Only two routes are compared which are the benzene route and the n-butane route since the

0-xylene route is only the recovery of maleic anhydride as byproduct.

N-butane route is chosen over the benzene route mainly due to benzene’s higher hazard

properties compared to n-butane and the rapid increase in benzene’s price over n-butane. In

addition, if viewed from the compound’s molecular properties, n-butane route still is a better

route. The reason is because there are four carbon atoms in product maleic anhydride per6

carbon atoms in benzene. Therefore, the atom efficiency for the carbon atom is 4/6 x 100% =

66.7%. In the n-butane route, there are four carbon atoms in n-butane per four carbon atoms

in maleic anhydride thus giving 100% atom efficiency. If mass efficiency is considered, then

the mass of the product is compared to the mass of the raw materials. The molecular weight

of maleic anhydride is 98. For the n-butane route, we need 1 mole of n-butane (molecular

weight 58) and 3.5 moles of oxygen (total mass of 3.5 x 32 = 112.) Thus the total mass of raw

materials needed is 170. The mass efficiency of the n-butane route is therefore 98/170 or

57.6%. By a similar calculation, we can show that the mass efficiency of the benzene route is

only 44.4%.

As can be seen, n-butane is favourable to benzene in comparison of both atom and mass

economy.

17

2.4 PHYSICAL AND CHEMICAL PROPERTIES

Properties

Maleic

Anhydride

(MAN)

Propane

Iso-butane N-butane Isopentane

Formula C2H2(CO)2O C3H8 C4H10 C4H10 C5H12

Chemical

structure

Molecular

weight

(g/mol)

98.06

44.1 58.12 58.12 72.15

Density

(g/ml) 1.48

0.584-42

0.6011 0.61972

Melting

point(◦C) 52.8

-188 -138 -138 -159.9

Boiling

Point(◦C) 202

-42.1 -11.7 -0.5 27.8

Flash

point(◦C) 103

-104 -87 -60 -56

Appearance

White

crystal Colourless

gas

Colourless

gas

Colourless

gas

Colourless

liquid

2.5 COST DATA

In building a production plant, initial capital investment as well as cost for operation and

maintenance needs to be considered. According to Silla (2003), there are three components

that contribute to the total production cost, which are direct costs, indirect costs and general

costs. Direct costs include feedstock supply, utilities supply and labour cost (Silla, 2003).

Indirect costs cover expenses like taxes, insurance and plant overhead costs (Silla, 2003). On

the other hand, general costs include administrative costs, marketing costs, etc. (Silla, 2003).

For the early stage of the market research, studies on the current market of the main product

(MAN) and the different feeds are performed. Research on the capital investment for existing

production plant is also presented in this paper.

MAN is mainly used as a raw material in the production of polyester resins, which are largely

used in boating, automobile and construction industries. Recently, a growing market of MAN

is observed in the production of butanediol, which is used in the synthesis of plastics and as a

18

textile additive. Apart from that, it is also been greatly used in the manufacture of alkyd

resins, a significant material in paints and coatings. Other applications that make use of MAN

include manufacturing of agricultural chemicals, lubricant additives and copolymers.

FIGURE 3: GLOBAL DEMAND OF MAN ACCORDING TO REGION(MALEIC ANHYDRIDE, 2011)

FIGURE 4: PRODUCTION CAPACITY OF MAN ACCORDING TO REGION, 2000 (TIMOTHY R.

FELTHOUSE, 2001)

In relation of the market demand and production capacity according to region, demand in

most regions is proportional to the production capacity (Maleic Anhydride, 2011). For an

instance, the highest demand of MAN comes from Asia (specifically China), and Asia also

has been the topmost producer of MAN (Maleic Anhydride, 2011). In United States, the price

of MAN is reported to be between USD 1,922 – 2,055 per tonne in 2011 (Timothy R.

Felthouse, 2001). The production capacity in US is reported to be up to 250,000tonnes/year

while their demand is 223,000 tonnes/year (Timothy R. Felthouse, 2001).

North America 23%

South & Central America

3%

West Europe 34%

East & Central Europe

4%

Asia 35%

Africa 1%

North America

South & Central America

West Europe

East & Central Europe

Asia

Africa

19

Globally, among companies that supply MAN are Bartek Ingredients Inc., BASF AG,

LANXESS Corporation and Huntsman Corporation (Jose, 2008). While in Asia, Changzhou

Yabang Chemical Co Ltd, Danyang Chemical Plant, and Thirumalai Chemicals Ltd are the

companies with MAN production (Jose, 2008). One company that produces MAN in

Malaysia is TCL Industries (Malaysia) SdnBhd (Jose, 2008). TCL Industries Malaysia is a

company under Thirumalai Chemicals Ltd that produces worldwide supply of up to 60,000

tonnes per year MAN (Maleic Anhydride, 2011).

Considering the world market outlook, China is found to be the main region for future

growth. This is due to the rise in demand of unsaturated polyester resin which requires MAN

for the production. Besides than Middle East, other countries such as Saudi Arabia and UAE

also are showing growth market and an increase in import requirements (ICIS,2002).

In a plant design study by Woril Turner Dudley (2012), to build a plant that produce about

USD 500,000 for a kmol product/hour MAN requires a capital investment of USD

18,161,381. This value can provide cost estimation in the future plant design for this project.

2.6 SITE FEASIBILITY STUDY

2.6.1 Introduction

Choosing strategic plant location is one of the most crucial decisions needs to be done. The

construction of a chemical plant requires a preliminary feasibility study to be done in order to

make certain that the proposed Kidurong Industrial Estate is feasible, economically and

environmentally. The location of the plant site takes relatively high precedence and it mainly

depends on the availability of feedstock, cost of production, marketing of the products, land

availability and also the infrastructure. The right location allows maximum profit with a

minimum operating cost and allowance for future expansion.

2.6.2 Selection Criteria

Based on the study done in the selecting strategic plant location, there are several factors that

should be taken into consideration when undertaking the process of selecting a suitable site.

There are two major factors that contribute to the operability and economic aspects of a site

location for a plant, which are the primary factor and specific factor.

20

TABLE 2: CONTRIBUTING FACTORS TO OPERABILITY AND ECONOMY ASPECTS

2.6.3 Summary of site Characteristic in Each Location

Five major locations are identified to be considered in the site selection for the construction

of Maleic Anhydride production plant. The locations are:

i) Kidurong Industrial Area

ii) Kota Kinabalu Industrial Park

iii) PasirGudang Industrial Estate

iv) PengerangIntergrated Petroleum Complex

v) Kerteh Petrochemical Complex

The characteristics of each location are listed based on the primary and specific factors which

had been justified before. Appendix 3 shows the summary of the site characteristics for each

location.

Primary Factors Specific Factors

Raw material supply for industry Availability of low cost labor

and services

Reasonable land price Safety and environmental

impacts

Source of utilities, such as electricity, water

and etc.

Incentives given by

government :

Pioneer Status

Investment Tax Allowance

(ITA)

Effluent and waste disposal

facilities

Climate status

Wind

Rainfall

Temperature

Relative Humidity

Transportation facilities

Local community

consideration

21

2.6.4 Site Evaluation

The evaluation of each location is done based on weightage system. Table 3 below shows the

range of weighted marks for each identified criteria. The site location is evaluated based on

the guidelines.

TABLE 3: WEIGHTAGE CRITERIA IN DECIDING SITE LOCATION

Factors 7-10 Marks 4-6 Marks 0-3 Marks

Supply of raw material Able to obtain large

supply locally thus

saving on import cost

Having long pipeline

networks for

transportation of raw

material

Source of raw

materials from

neighbouring states or

countries with the

distance not exceeding

80km.

Uses a pipeline system

as well.

Unable to obtain raw

material from close

sources with the

distance exceeding

80 km

Forced to import

from foreign

countries

Uses a pipeline

system as well.

Price and Area of Land Land area exceeding

60 hectares

Price of land below

RM 20 psm

Land area below 60

hectares

Price of land more

than RM 20 psm

Land area below 40

hectares

Price of land more

than RM 30 psm

Local Government

Incentives

Incentives from the

local organization of

country development

Incentives from

special company

Incentives from the

local organization of

country development

No incentives from

the local organization

of country

development

Transportation Complete network

and well maintained

highways,

expressways and

roads

International Airport

facilities access to the

main location around

the world

Location near to

international port

which import and

export activities

Reliable railway lines

to remote areas not

accessible by roads

Good federal road and

highway system

Limited railway

system access

More distant from the

ports

Airport facilities

which may not have

international flight

facilities- only

providing domestic

flight

Average road system

No highways or

expressway system in

close proximity

No railway system

Very distant from the

ports or harbours

Distant form the

nearest airport more

than 100km away

22

TABLE 4: WEIGHTAGE TABLE ON SITES

Criteria

Kidurong

Industrial

Site

Kota

Kinabalu

Industrial

Park

PasirGudang

Industrial

Estate

PengerangIntergrated

Petroleum Complex

Kerteh

Integrated

Petrochemical

Complex

Supply of Raw

Material 10 8 9 9 10

Price 8 1 9 10 4

Area of Land 10 7 4 9 4

Local

Government

Incentives

9 8 8 8 8

Transportation 9 8 6 6 10

Workers Supply 10 7 10 9 98

Utilities, water

and electricity 8 8 9 7 9

Type of industrial

and its location 10 3 5 10 10

Waste water

disposal 10 8 10 9 9

Total 84 58 70 86 73

Percent (%) 84 58 70 86 73

Based on the weight matrix, the selected location for MAN plant construction is Kidurong

Industrial site. The location is justified to be the most suitable and strategic compared to the

others based on all the criteria.

Some of the attractive information of the location is as followed:

Kidurong Industrial site is located only 20 km with approximately 15 minutes from

Bintulu Town. It is identified as the main industrial core of the whole Bintulu area

which is one of the attractions of multinationals oil and gas companies.

It consist of a few established multinational oil and gas company such as MLNG

complex, which is deemed as the world largest single gas manufacturing complex

apart from Shell and Murphy.

23

FIGURE 5: KIDURONG INDUSTRIAL AREA

Include related infrastructure such as Bintuludeepwater Port, Bintulu Airport and a

few options of power supply.

The available MLNG Complex is targeted as the main supply of raw material for

Malefic Anhydride production plant.

The land price is cheap and reasonable compared to the other established locations which are

around RM77.42. The available land is also huge and sufficient enough for the construction

of MAN plant.

2.7 POTENTIAL HAZARDS

2.7.1 Previous Accident On Similar Plant

The plant was located in Indonesia. The fire incident was started on 20th

January 2004. This

chemical factory was doing processing which involved ammonia and maleic anhydride. The

plant employs some 450 people and makes chemicals used in plastics.

The blasts were sparked by a fire in several tanks. The fire caused a leak of maleic anhydride

from the top of a tank, which ignited, increasing the intensity of the fire. The fire was also

threatening some ammonia tanks. Flames were 50 meter high and smoke could be seen

several kilometers away. The blaze destroyed at least 5 nearby homes and more than 50 fire

trucks were deployed at the height of the fire but only masked firefighters could approach the

blaze. The state electricity company cut power to the area. The company shut down pipeline

that supplied gas to the industrial complex. The fire was caused by an overheated machine.

Fifty-six were injured. Most of them suffered serious burns. The death toll in the devastating

fire at a chemical plant increased to three after another victim died from severe burns in

24

hospital. A 36-year-old man sustained burns to more than 90% of his body and at last died

after several days. The man was one of the 13 victims being treated in a hospital, who

suffered more severe burns in the fire. Three other victims died hours after the fire engulfed

the chemical plant. Among them were the plant and production director. Police has evacuated

hundreds residents within 1 kilometer of the plant. More than 100 firemen and police battled

to put out the blaze. There was the sound of at least five explosions before a column of black

smoke rose into the sky. The resulting fire lasted until 2330 hours while thick black smoke

covered the sky until 1800 hours. The people have complained of eye irritations from a huge

pall of smoke. Hundreds of workers are taking indefinite vacations. It has been discovered

that the communities living in the surrounding area, have complained about water

contamination in their wells. The water has a foul smell and when used for bathing the

community reports it causes itchiness.

2.7.2 Potential Hazards and Control Measures

Production of MAN from normal butane requires a process with high pressure and

temperature. In addition to that, the reactant used in this petrochemical industry is highly

flammable and reactive with oxidizing agent. These conditions made the process plant

become relatively hazardous compared to other industries like food and manufacturing

industries. Potential hazards are grouped according to its common source, and the hazards

effects and control measures are summarized in the table below.

TABLE 5: ANALYSIS OF POTENTIAL HAZARDS

Source Potential Hazards Effects Control Measures

Chemical Tank, Storage &

Transportation

Dangerous chemical reaction,

overpressure, temperature above flash

point, corrosion of storage tank, release of

toxic fume, chemical spillage

Fire

Explosion

Air pollution

Land pollution

Replace hazardous chemical with a less hazardous

alternative

Isolation of incompatible chemicals

Installation of pressure safety valve

Filtration of toxic fume

Warning signage/ label for chemicals

Store chemical in well-ventilated area

Reactor Overpressure, overheat, sudden

temperature rise Explosion

Utilize overpressure relief protection

Implement control system to prevent overheat and

overpressure condition

Installation of pressure safety valve

Distillation Column High pressure Flooding

Sequence the distillation process for a minimum flow of

non-key components


Heat Transfer Overpressure, fouling, overflow of

cooling or heating medium

Tube rupture

Leaking

Contamination of

liquid

Thermal shock


Substitution to a less hazardous cooling or heating

medium

Use control valve to prevent thermal shock

Utilities (Electricity, gas, water,

etc.) Short circuit, ignition Fire

Explosion

Ensure proper connections and maintenance for

electrical components

Keep flammable material away from ignition source

Layout Unsafe layout (poor arrangement, limited

space to perform safe work) Create less

conducive, accident-

prone workplace

Ensure safe and practical design of process plant,

considering safe operational sequence and future

expansion

Separate process and non-process area.

Ensure proper ventilation

Location Natural disaster, approval from local

community

High risk of disaster

Pollution affecting

community (noise,

air, etc.)

Selection of site with minimal risk of natural disaster

Keep safe distance between the plant site and the local

community

Environment Untreated waste water Water pollution Develop a treatment system for waste water

2.7.3 Material Safety Data Sheet (MSDS) & Hazard

TABLE 6: HAZARD ANALYSIS

Chemicals Flash

point

Auto-Ignition

Temperature Fire & Explosion Reactivity Symptoms / Effects

Maleic

Anhydride 102

oC 477

oC

Combustible when exposed to heat

or flame. Material in powder form,

capable of creating a dust explosion.

When heated to decomposition it

emits acrid smoke and irritating

fumes.

Reactive with oxidizing

agents, reducing agents,

acids, moisture. Slightly

reactive to reactive with

metals, alkalis.

Exposure will cause asthma,

dermatitis and pulmonary

oedema; effects may be delayed.

Tumorigen.

n-butane -

60.15oC

286.85oC

Extremely flammable in the

presence of following materials or

conditions: open flames, sparks and

static discharge and oxidizing

materials.

The product is stable.

Contact with rapidly expanding

gas may cause burns and or

frostbite. Acts as a simple

asphyxiant.

Propane -104oC 450

oC

Explosive air-vapor mixtures may

form if allowed to leak to

atmosphere.


Higher concentrations may cause

dizziness and unconsciousness

due to asphyxiant. Liquid can

cause burns and frostbite if in

direct contact with skin.

27

Chemicals Flash

point

Auto-Ignition


iso-butane -82.8oC 460

oC

Flammable liquid and gas

under pressure. Form

explosive mixtures with air

and oxidizing agents.

Stable. Avoid from high

temperature and incompatible

materials such as oxidizing

agents.

May be mildly irritating to

mucous membranes. At high

concentrations, may

cause drowsiness. At very high

concentrations, may act as an

asphyxiant and cause headache,

drowsiness, dizziness, excitation,

excess salivation, vomiting, and

unconsciousness. Lack of oxygen

can kill.

isobutene -76oC 465

oC Extremely flammable.

Can form explosive mixture

with air. May react violently

with oxidants.

In high concentrations may cause

asphyxiation. Symptoms may

include loss of mobility /

consciousness. Victim may not be

aware of asphyxiation. In low

concentrations may cause narcotic

effects. Symptoms may

includedizziness, headache,

nausea and loss ofco-ordination.

1-butene -80oC 384

oC

Forms explosive mixtures

with air and oxidizing agents.

Avoid exposure to

incompatible materials such

as oxidizing agents, halogens,

and acids. Avoid to elevated

temperatures, and pressures or

the presence of a catalyst.

Asphyxiant. Moderate

concentrations may cause

headache, drowsiness, dizziness,

excitation, excess salivation,

vomiting, and unconsciousness.

Lack of oxygen can kill.

28

Chemicals Flash

point

Auto-Ignition


Neopentane < -7oC 450

oC

Severe fire hazard. Severe

explosion hazard. The vapor is

heavier than air. Vapors or

gases may ignite at distant

ignition sources and flash

back. Gas/air mixtures are

explosive.

Stable at normal temperatures

and pressure. Avoid heat,

flames, sparks and other

sources of ignition. Minimize

contact with material.

Containers may rupture or

explode if exposed to heat.

High concentrations can cause

eye and respiratory mucous

membrane irritation and mild

narcotic symptoms, or loss of

consciousness. Long-term

exposure can induce mild

dermatitis.

Isopentane -51oC 420

oC

Flammable in presence of

open flames and sparks.

Slightly flammable to

flammable in presence of

oxidizing materials.


Hazardous in case of eye contact

(irritant), of ingestion, of

inhalation. Slightly hazardous in

case of skin contact (irritant,

permeator).

n-pentane -49oC 260

oC

Extremely flammable in

presence of open flames and

sparks, of heat. Flammable in

presence of oxidizing

materials. Nonflammable in

presence of shocks. Slightly

explosive in presence of heat,

of oxidizing materials. Non-

explosive in presence of

shocks.

Stable at room temperature in

closed containers under

normal storage and handling

conditions.

Can causes eye and skin irritation.

Ingestion may cause central

nervous system depression,

characterized by excitement,

followed by headache, dizziness,

drowsiness, and nausea.

Inhalation may cause respiratory

tract irritation.

Oxygen -52.2oC N/A

Oxidizing agent can

vigorously accelerate

combustion. Contact with

flammable materials may

cause fire or explosion.

Extremely reactive or

incompatible with the

oxidizing materials, reducing

materials and combustible

materials.

Breathing 80% or more oxygen at

atmospheric pressure for more

than a few hours may cause nasal

stuffiness, cough, sore throat,

chest pain, and breathing

difficulty.

29

Chemicals Flash

point

Auto-Ignition


Water N/A N/A N/A N/A No acute and chronic health

effects.

Carbon

Dioxide None None Non-flammable.

Stable. Certain reactive

metals, hydrides, moist

cesium monoxide, or lithium

acetylene carbide diammino

may ignite. Passing carbon

dioxide over a mixture of

sodium peroxide and

aluminum or magnesium may

explode.

Moderately irritating to the eyes,

skin, and respiratory system.

Carbon

Monoxide

Not

available. 700

oC

Severe fire hazard. Vapor/air

mixtures are explosive.

Containers

Stable at normal temperatures

and pressure.

Incompatibilities

withoxidizing materials,

halogens, metal oxides,

metals, combustible materials,

lithium

Harmful if inhaled, blood

damage, and difficulty breathing.

Causing blisters, frostbite, and

blurred vision. may rupture or explode if

exposed to heat.

30

CHAPTER 3: CONCEPTUAL PROCESS DESIGN AND SYNTHESIS

3.1 LEVEL I: PROCESS OPERATING MODE

For any chemical process, there are two mode of operation that a plant can choose to operate;

batch process and continuous process. The choice of best mode of operation follows these

guidelines as in the table shown below:

TABLE 7: GUIDELINES FOR BATCH AND CONTINUOUS PROCESS

Guidelines Batch Continuous

Production rate Production less than 10 x 106 lb

per annum

Production more than 10 x 106 lb

per annum

Availability Product is a seasonal product

Raw material are limited

Product is a commodity product

Raw material are always available

Purpose Suitable for research purposes Suitable for mass production

(profit purposes)

Lifetime of

Product Short Long

Our selection for the mode of operation of our plant is discussed in detail for each

guideline point:

i. Production rate

Our targeted capacity is 50 000 metric ton per annum, which is bigger than 10

million pound per annum (4 535.9237 metric ton per year).

ii. Availability

Maleic anhydride is a commodity product, which need to be available all year

due to its extensive usage in the industry.

iii. Purpose

Our maleic anhydride plant obtains profit by its mass production of its product in

most economical process route as possible.

iv. Lifetime of the product

31

The demand for maleic anhydride is projected to increase and for that, the

lifetime for the product is long.

v. Operational problem

Maleic anhydride is usually produced in a gas state before being cooled and

stored as liquid product. With that, it has low operational problem.

From all the points discussed above, the best choice of mode of operation for our plant is

continuous process as the product is produced in large quantity, the product is a

commodity product, it has long lifetime and the process has low operational problem.

3.2 LEVEL II: INPUT-OUTPUT STRUCTURE

The process of ammonia is shown below. According to Douglas, to fix the input and

output structure, a box is drawn around the process. Then the focus is on what are the

feed for the process and what are the product and by-product that comes out from the

process:

FIGURE 6: SCHEMATIC PROCESS OF AMMONIA

To complete the input and output structure of the plant, some check question should be

answered in order to fix the structure above. The check questions are as shown below:

1. Should we purify the feed stream before they enter the process?

2. Should we remove or recycle a reversible by-product?

3. Should we use a gas recycle and purge stream?

4. Should we not bother to recover and recycle some reactants?

32

We will address each check question in detail in order to synthesize our plant’s input and

output structure.

Q1. Should we purify the feed stream before they enter the process?

By composition, our mixed butane feed consists of approximately 32% unwanted

components (such as iso-butane, propane and pentane). These chemicals, without

removing it first will affect the reactivity and selectivity of reaction in the reactor.

For that reason, the feed should be treated first before being fed into the system.

Q2. Should we remove or recycle a reversible by-product?

The by-products of MAN production are water, carbon dioxide, and carbon

monoxide. These are non-reversible product so there is no need for recycle

stream for the by-product.

Q3. Should we use a gas recycle and purge system?

The process is a high pressure process; the pressure in the MAN synthesis loop is

250kPa. Gas stream that remains after the product being recovered contain some

amount of nitrogen. Nitrogen is inert and did not take part in the MAN

conversion. They tend to accumulate in the process loop as the reaction take

place continuously. This could increase the pressure inside the loop. Therefore,

these inert should be taken out and be purged.

Q4. Should we not bother to recover and recycle some reactant?

Process air, a reactant is being used in excess in this process. Since process air is

relatively inexpensive compared to mixed butane, we are not bothered to recover

the reactant. However, water collected from the moisture separator vessel can be

reheated back to steam using the high energy transferred into the furnace, which

can be used in the system. This could save some amount of cost since steam is a

type of utility in the plant.

3.3 LEVEL III: REACTOR DESIGN AND REACTOR NETWORK

SYNTHESIS

Reactors play an important role in all plant especially chemical plant, where the chemical

reaction is taking part. As shown by onion model, reactor is said to be the heart of the

33

whole plant. In other words, reactor is the most important equipment among all in the

chemical plant. As a result, no reactor means no reaction will occur. Without any

reaction, there will be no product produced. From the reactions, mass transfer as well as

chemical kinetics and others are calculated.

3.3.1 Reactor Conversion Selections

The chemical reactions involved in the production of Maleic anhydride consist of one

main reaction and one side reaction.

C4H10 + 3.5O2 C4H2O3+ 4H2O [1]

Butane oxygen maleic anhydride water

C4H10 + 5.5O2 2CO + 2CO2 + 5H2O [2]

Butane oxygen carbon monoxide carbon dioxide water

TABLE 8: PRODUCTION OF MALEIC ANHYDRIDE FROM N-BUTANE

(BLUM & NICHOLAS, 1982)

An ideal reactor will have a high selectivity on the desired product. In evaluating reactor

performance, selectivity is more meaningful to consider than reactor yield. (Smith)

Thus, the % conversion with the highest selectivity is selected which is a % conversion

of 82.2 with a % yield of 57.6 and a % selectivity of 70. The selectivity for carbon

dioxide is 20%.(Slinkard & Baylis, 1975)

34

3.3.2 Preliminary Reactor Mass Balance

Preliminary mass balance calculation for reactor is as below.

TABLE 9: PRELIMINARY REACTOR MASS BALANCE

Component

Mass flow rate kg/hr

In Out

Isobutane 1287.80 1287.80

n-butane 6560.33 1167.74

Oxygen 39730.87 27884.01

Maleic anhydride 0.00 7158.16

Carbon monoxide 0.00 1168.42

Carbon dioxide 0.00 1835.85

Water 3195.32 10021.49

Nitrogen 130843.36 130843.36

EP1 = Product-Reactant

= (RM 6 566.43/ton x 51958tonne/yr) –

[(RM 2858.34/ton x 56693tonne/yr)

= RM 179 130 700.3/year

Assuming that the n-butane can be recycled back as feed, the opportunity to optimize the

reactor is as below.

in

Reactor

out

35

TABLE 10: MASS BALANCE WITH RECYCLE

Component

Mass flow rate kg/hr

In recycle Out

Isobutane 1287.80 0 1287.80

n-butane 5392.59 1167.74 1167.74

Oxygen 39730.87 0 27884.01

Maleic anhydride 0.00 0 7158.16

Carbon monoxide 0.00 0 1168.42

Carbon dioxide 0.00 0 1835.85

Water 3195.32 0 10021.49

Nitrogen 130843.36 0 130843.36

EP1 = Product-Reactant

= (RM 6 566.43/ton x 51958tonne/yr) –

[(RM 2858.34/ton x 42709tonne/yr)

= RM 219 101 726.9/year

The % increase in profit is = (219101726.9-179130700.3)/179130700.3 X 100

= 22,31%

The increase in profit is mainly due to the less usage of n-butane as feed. However, the

removal of low boiling point components (nitrogen, oxygen, carbon monoxide, isobutene

and carbon dioxide) besides n-butane from the recycle stream will cause the loss of most

of the n-butane unless the stream is cooled below the boiling point temperature of n-

36

butane which is typically below cooling water temperature and is not preferred as

refrigeration is required which will be costly.

3.3.3 Reactor Type Selection

The choice selection of type reactor is between two types which is the fixed bed reactor

(FBR) and the fluidized bed reactor (FBR).

The advantages and disadvantages of PBR are summarized below:

TABLE 11: ADVANTAGES AND DISADVANTAGES OF PACKED BED REACTOR (SMITH)

Advantage Disadvantage

High ratio of heat transfer area to

volume

Can be used for multiphase reaction

Use during careful control of residence

time

Have mechanical advantage at high

pressure

Difficult to control temperature due to

varying heat load in bed

Catalyst temperature can be locally

excessive giving hot spots

Off line catalyst regeneration

The advantages and disadvantages of FBR are summarized below:

TABLE 12: ADVANTAGES AND DISADVANTAGES OF FLUIDIZED BED REACTOR

Advantage Disadvantage

Good heat transfer and

temperature uniformity

Useful for frequent catalyst

regeneration (online

regeneration)

Attrition of catalyst can cause carryover

Back mixing on the kinetics in the reactor,

product destruction and by-product reactions

in the space above the fluidized bed

Vulnerability to large-scale catalyst releases

from explosion venting

Require a significant amount of space above

the catalyst level to allow the solids to

separate from the gases. This exposure of the

product to high temperatures at relatively

long residence times can lead to side

reactions and product destruction

37

The temperature of the reactor is around 400-500 0C due to the highly exothermic

reaction involved. At this temperature the components are in gas phase. The removal of

heat from the reactor is important and is the key to the reactor type selection.

The packed bed reactor (PBR) is chosen over the fluidized bed reactor (FBR) due to

several reasons.

As shown in the Tables 11 and 12 above, both reactors have a relatively good heat

transfer rate. Although the FBR have a slight advantage of good control of the

temperature uniformity, control of the hot spots and online catalyst regeneration but the

usage of the FBR is quite new in the industry and the understanding of the FBR model is

new and not complete as a whole. In addition, the disadvantages of the FBR such as back

mixing and catalyst venting also has an impact on the destruction of the product and

impact on the environment and safety point of view. Nevertheless, there are suggested

strategies to overcome the disadvantages like several proposed patents that claim can

control back mixing and also cooling the reactor effluent to prevent the catalyst

carryover to foul the heat exchangers. However, these strategies are relatively new and

not fully established.

Meanwhile, the existence of the PBR is since the production of MAN from benzene

before the usage of n-butane. Several strategies have been successfully implemented to

overcome the problem with the temperature control and hot spots. Among them are using

a small diameter and by using a profile of catalyst through the reactor to even out the

rate of reaction and achieve better control. Several reactors can be installed to overcome

the off line catalyst regeneration. In addition, the exothermic heat of reaction is removed

from the salt mixture by the production of steam in an external salt cooler. Efficient

utilization of waste heat from a maleic anhydride plant is critical to the economic

viability of the plant. The steam can be used to drive an air compressor, generate

electricity, or both. There is also the opportunity to have other equipment to operate at a

higher operating temperature giving a better performance of the equipment knowing that

there is excess waste. This can cut cost by reducing extra equipment for the separation

train.

38

3.4 LEVEL IV: SEPARATION SYSTEM SYNTHESIS

Having made initial specification for the reactor, attention is turned to separation of the

reactor effluent in the process route screening. This is in line with the heuristic approach

for the separation train sequence.

FIGURE 7: HEURISTIC METHOD: ONION MODEL

However, considering that the feed is not of pure n-butane, there is a need to carry out

separation before the reactor to purify the feed. A distillation column which is the

benchmark for the separating equipment is chosen to separate out the n-butane to

increase the purity of the feed.

The procedure followed in deciding the process route using the heuristic method is as

follows:

Decide on type of separator that will be likely used for the required separation

Decide on the sequencing of the separator to achieve the process requirement

39

The golden rule for separation is to separate heterogeneous mixtures as soon as it forms.

However the reactor effluent is of homogeneous mixture.

The first choice for separating homogeneous mixture is using the distillation column.

Nevertheless, separations using distillation column have circumstances not favoring

distillation as below:

1. Separation of low molecular weight materials

2. Separation of high molecular weight heat sensitive material.

3. Separation of components with low concentration.

4. Separation of classes of components

3.4.1 First Process Route

The reactor effluent mainly consists of gases like nitrogen, oxygen, carbon monoxide

and carbon dioxide. Thus, separation of the gases which is a class of component cannot

be done using distillation column. Alternatives of separation include the creation of

another phase within the system by changing the temperature or pressure or by addition

of a mass separation agent. This can be done by using an absorber. Since changing the

operating parameters require the usage of heating or cooling and the component

interested to be separated is the gases, the mass separation agent is used to absorb MAN

from the effluent.

Water is usually used as the standard mass separation agent (MSA). Alternatively, there

are also other organic mass separation agents that can be used but for the first process

route, the standard water is used. The usage of other mass separation agent will be

discussed in the second process route.

The water exiting the absorber contains dissolved MAN and also maleic acid which is

the reaction of MAN and water. Water is the major component fraction in the stream

exiting the absorber. Another phase separation can be done easily by increasing the

temperature to remove a large amount of water. The flash drum is used to separate the

different phases after the temperature is increased.

After the flash drum, the maleic acid needs to be converted back to MAN before the

proceeding to further separate the water. For this purpose, a reactor is used to convert

back the acid into MAN at a specified temperature.

40

After the maleic acid reactor, a distillation column can be used to separate water and

MAN. However, according to UNIFAC thermodynamic package, MAN and water forms

azeotrope which makes the mixture hard to separate. To overcome the hard separation,

two distillation columns operating at different pressures are needed to separate the water.

FIGURE 8: FIRST PROCESS ROUTE

3.4.2 Second Process Route

The second process route considers the usage of other MSA in the absorber. Among the

commonly used mass separation agent for the process are dibutyl phthalate, dibutyl

terephthalate, dimethyl phthalate and diisopropyl phthalate. According to Chen (2002),

dibutyl phthalate (DBP) is best used for n-butane processes. Thus, it is chosen as the

MSA for the second route.

The DBP absorbs most of the MAN and small amounts of water. The MSA then needs to

be regenerated through the separation of DBP from MAN and water. Usually, a stripper

is used for the regenaration of the MSA. However, DBP can be separated from MAN

without using a gas stripper. Hence, a stripper distillation column which is a typical

distillation column is used to separate the DBP. Since the amount of water together with

MAN is relatively small, the purity of the MAN separated is at 99 weight %. So, further

41

purification will need two more distillation column to further separate the azeotrope

mixture which will be uneconomical.

FIGURE 9: SECOND PROCESS ROUTE

3.4.3 Process Route Selection

The second process route is selected over the first process route. This is because more

equipment is used in the first route due to the production of maleic acid when water

reacts with MAN. In addition, the usage of water as the MSA requires two distillation

columns to separate the azeotrope mixtures. On the other hand, the usage of dibutyl

phthalate as the MSA simplifies the separation train sequence. Although DBP is more

expensive than water, but according US Patent 5069687 and US Patent 4071540, the

usage of DBP is more energy efficient due to the avoidance of the evaporation of water

and effective in absorbing 99.4% of the MAN. Moreover, due the small amount of water,

the MAN exiting the stripper distillation column is already at more than 99 weight % so

further purification is not needed.

3.5 LEVEL V: HEAT INTEGRATION

3.5.1 Introduction to Pinch Analysis

Pinch analysis is a well-established tool that determines the minimum energy

requirement and the optimumdesign of heat exchanger network. This analysis enables a

plant design to reach the following goals:

Maximizing heat recovery of the system.

Minimizing heating and cooling utility consumption.

Optimizing the selection of utility sources.

42

Optimizing the trade-off between energy costs and capital cost.

3.5.2 SPRINT Software

In integrating heat network into the design, SPRINT software is used. This software may

be used to develop composite curve, problem table algorithm, and grand composite curve

based on the stream data inserted by a user. This software is also capable of detecting

infeasibility of a heat exchanger network design if there is any temperature violation. In

short, SPRINT software facilitates the necessary calculations for heat integration.

3.5.3 Stream Data Extraction

The first step in performing heat integration is to extract information of streams that

require heat duty. These are streams that require change in temperature. The streams that

are selected for heat integration will exclude streams for equipment (such as reboiler and

condenser). Stream data extracted for this project can be tabulated as follows:

TABLE 13: STREAM DATA EXTRACTED

Type Stream Ts

(°C)

Tt

(°C)

H

(kW)

CP

(kW/°C)

H1 Hot Reactor exit 500.0000 125.0000 20,619.0904 54.9842

H2 Hot Solvent feed 250.0000 35.0000 7,027.2561 32.6849

C1 Cold Feed vaporizer 25.0000 85.0000 854.8509 14.2475

C2 Cold Deisobutanizer bottom 75.8398 120.0000 320.0433 7.2473

C3 Cold Mixer output 116.7270 310.0000 10,187.2383 52.7091

Information on supply temperature (Ts), target temperature (Tt) and heat duty (H) are

generally extracted from process flow diagram (PFD) made by iCon simulation. CP is

assumed constant at any temperature and is calculated using the following equation:

The streams extracted are categorized into hot and cold streams. A stream is defined as

hot when it is surplus in heat (requires cooling) and cold stream when it is deficit in heat

(requires heating).

43

3.5.4 Minimum Temperature Difference

Temperature difference between hot stream and cold stream is the driving force for heat

transfer between the two profiles. Minimum temperature difference, Tmin, is the lowest

potential driving force, below which heat transfer is unlikely. Tmin determines the

amount of heat recovery in a system. When Tmin is lower, the potential heat recovery

from process will be higher. However, according to application experience by KBC

Energy Service, the typical Tmin value varies according to industry (Pinch Analysis).

TABLE 14: OPTIMUM TMIN IN DIFFERENT INDUSTRIES (PINCH ANALYSIS)

Industrial sector Typical

ΔTmin (°C) Remarks

Oil refining 20 – 40

Relatively low heat transfer coefficients, parallel

composite curves in many applications, fouling of

heat exchangers

Petrochemical 10 – 20 Reboiling and condensing duties provide better heat

transfer coefficients, low fouling

Chemical 10 – 20 As for petrochemicals

Low temperature

process 3 - 5

Power requirement for refrigeration system is very

expensive. ΔTmin decreases with low refrigeration T

Maleic Anhydride production plant is a petrochemical industry. Hence, the optimum

Tmin according to the table above is in range of 10°C – 20°C. For this project, Tmin of

10°C is selected so as to maximise heat recovery from the system.

3.5.5 Maximum Process Heat Recovery

Initially, the plant is designed so as all the heating and cooling requirements are satisfied

by using utilities. The table below indicates the total hot and cold utility requirement

before heat integration:

44

TABLE 15: UTILITIES REQUIRED BEFORE HEAT INTEGRATION

Type Stream H

(kW)

H1 Hot Reactor exit 20,619.0904

H2 Hot Solvent feed 7,027.2561

Total cold utility required 27,646.3465

C1 Cold Feed vaporizer 854.8509

C2 Cold Deisobutanizer bottom 320.0433

C3 Cold Mixer output 10,187.2383

Total hot utility required 11,362.1325

By applying pinch analysis, we target on maximizing energy recovery from the process

so that the utility requirement can be minimized. The maximization of process heat

recovery can be visualized using a composite curve as shown below:

FIGURE 10: COMPOSITE CURVE FOR MAXIMUM HEAT RECOVERY:

With the input of extracted stream data, SPRINT software calculates the maximum heat

recovery from process streams and the minimum utility requirement. In composite curve,

the maximum process heat recovery is represented by the range of heat load where hot

45

profile and cold profile overlap. The maximum process heat recovery, minimum cold

utility (Qcmin), and minimum hot utility (Qhmin) requirements are as follows:

TABLE 16: UTILITIES REQUIRED AFTER HEAT INTEGRATION

Utility H

(kW)

Minimum cold utility (Qcmin) 16,284.2140

Minimum hot utility (Qhmin) 0.0000

The values of pinch temperature, Qcmin, and Qhmin can also be obtained from problem

table algorithm (PTA). Figure below shows the PTA acquired using SPRINT software.

FIGURE 11: PROBLEM TABLE ALGORITHM BY SPRINT SOFTWARE

From the PTA, the pinch temperature, .

Therefore,

46

3.5.6 Heat Exchanger Network

Based on information extracted on PTA, pinch point is located at the highest shifted

temperature (495C). This means that the overall system existed below the pinch.

Therefore, only analysis of heat integration below the pinch is relevant. Prior to decision

on the best heat exchanger network, estimation of the minimum number of heat

exchanger units, Nunit, can be made using the following equation:

Where

From the equation,

During pairing of the streams, two rules must be obeyed to ensure the network is

feasible. The rules are:

The T between a pair of hot stream and cold stream must always be ≥ 10C.

CP rule (i.e. CPhot≤ CPcold for above pinch and CPhot≥ CPcold for below pinch)

must not be violated unless the pair is away from pinch.

Figure below illustrate the heat exchanger network designed for this plant.

FIGURE 12: HEAT EXCHANGER NETWORK

After creating heat exchanger network, it can be summarized that the total number of

heat exchangers for the plant is 5 units. Process heat recovery can be sum up to

Tpinch hot, 500°C

H1 500 125

H2 250 35

C1 85 25

C2 120 75.8

C3 310 116.7

Tpinch cold, 490°C

10,187 kW

320 kW

10,432 kW

5,852 kW

314.72C

855 kW

240.21 C 214.05C

47

11,362.1325kW. The amount of cold utility requirement is 16,284.2140 kW, while no

hot utility is required.

3.5.7 Energy-Saving Evaluation

Comparison of heat utility requirements before and after heat integration (HI) can be

summarized into the following table:

TABLE 17: COMPARISON OF UTILITY REQUIREMENT BEFORE AND AFTER HI

Utility

Requirement

Heat Duty (kW)

% Saving

Before HI After HI

Hot utility, Qh 11,362.1325 0.0000 100.0%

Cold utility, Qc 27,646.3465 16,284.2140 41.1%

Total 39,008.4791 16,284.2140 58.3%

Percentage saving can be calculated using the following formula:

Referring to the table above, it is observed that there is a huge reduction in utility

requirement after pinch analysis is applied. The plant can eliminate 100% of the

requirement for hot utility, while the amount of cold utility can be reduced up to 41.1%.

As an overall, heat integration implemented can minimize the plant’s operating cost by

minimizing utility requirement, as well as reducing capital cost by minimizing the

number of heat exchangers during heat exchanger network design.

48

CHAPTER 4: INSTRUMENTATION AND CONTROL

4.1 INTRODUCTION

A safe mode operating chemical plant requires a good control system around the

equipment by installation of relevant instrumentations in achieving its target production.

This is to ensure that the operation of the plant could be conducted in the most

economical way and avoid accidents that may lead to the upset value of the production.

The objectives of designing the control system strategy are:

To have a safer operation plants and avoid accidents such as explosion

To maintain the operational condition of the unit operation at their own

respective condition

To control the process that is in line with the production rate

To maintain the product purity as high as possible

To avoid excess usage of heating and cooling utilities

4.2 DESIGN OF PLANT WIDE CONTROL SYSTEM

4.2.1 Procedures

The four major steps in designing the plant wide control system are;

i. The overall specification for the plant and its control system are stated.

ii. The control system structure, which includes selecting controlled, measured and

manipulated variables, product quality, handling operating constraints, is

developed.

iii. Detailed specification of all instrumentation, cost estimation, evaluation of

alternatives and the ordering and installation of unit operation are available.

iv. Design and construction of the plant and plant tests (startup, operation at design

conditions and shutdowns) are known.

However, for this plant, the steps taken are only;

i. Identification of controlled, manipulated and disturbance variables are

developed.

49

ii. Appropriate control strategies are implemented.

The Process &Instrumentation Diagram (P&ID) for the whole plant is attached in the

Appendix 2.

4.2.2 Drier Control System

The purpose of the control system is to maintain the desired water content in the air

which is fed into the reactor. The control system consists of pressure and level

controller. The drier is a flash vessel whereby flashing of the air occur at a specified

temperature and pressure to remove water.

TABLE18: DRIER CONTROL SYSTEM DETAILS

Controlled variable Manipulated variable Type of controller Set Point

Pressure of the flash

vessel

Vapour flow rate Feedback Control

Pressure :

1480kpa

Level of the flash

drum

Air inlet flow rate Feedback Controller Level: 70%

4.2.3 Deisobutanizer Control System

The control system in the deisobutanizer column is important in order to have an

accurate separation between the components and to ensure good ratio of purity. Basically

the process is applying the distillation concept; the only different is the different take off

point at the trays. The control system must be able to cause the average sum of the

product streams to be exactly equal to the average desired stream. It must also be able to

maintain the desired concentration of products at the bottom and the top streams. Control

requirements for deisobutanizer, K-1 are:

Pressure in the column

Feedback control is used to control the operating pressure at the top of the column

to avoid overpressure.

Level of the liquid at the bottom of the column

50

The liquid level is controlled by manipulating the outlet of the bottom product flow

rate using feedback control system.

Temperature of the column

The reflux temperature is controlled by manipulating the inlet flow rate of low

pressure steam (LPS) entering the reboiler by using the feedback control.

Reflux temperature

The temperature difference must not exceed the critical temperature difference. The

temperature indicator and controller installed at the condenser outlet controls the

temperature by manipulating the cool water supply (CWS) line.

Reflux ratio

A flow indicator and controller is installed at the reflux line cascaded with flow

indicator and controller of the distillate line to control the flow of the reflux back

into the column. Ratio control will maintain the ratio of the reflux line and distillate

line at the set point.

TABLE19 : DEISOBUTANIZER CONTROL SYSTEM DETAILS

Controlled variable Manipulated variable Type of controller Set Point

Pressure in the column Top outlet vapor flow

rate

Feedback control

Pressure:

1100 kPa

Bottom liquid level Bottom liquid outlet

flow rate

Feedback control

Level: 80 %

Bottom temperature Steam inlet flow rate Feedback control

Temperature:

75.8 oC

Reflux temperature Cooling water supply

flowrate

Feedback control

Temperature:

55.4 0C

Reflux ratio Outlet gas flow rate Ratio control Reflux ratio: 1.8

4.2.4 Reactor Control System

For the control system design at the reactor, C-1, several requirements have to be made;

Feed flow rate of the two inlet streams into the reactor

The flow rate into the reactor has a certain ratio value for the ideal reaction to

occur or otherwise, accidents such as explosion may occur at any time during the

51

operation. The ratio is set at least 1.7% oxygen. Therefore, these two inlet

streams have to be adjusted at this desired value so that accident will not occur by

controlling it with a ratio controller. Both are feedforward controller and are

interconnected with a ratio controller to ensure that the desired ratio of the feed

stream can be obtained.

Temperature of the reactor

On top of that, the temperature inside the reactor is controlled by manipulating

the bypass supply stream of the refrigerant and the bypass feed flow rate to the

reactor using feedback controller. The flow rate of molten salt (MS) will

determine and change the temperature inside the reactor until it reaches the

desired set point. In addition, for further safety reason, the feed flow rate will be

decreased if the temperature goes too high.

Additional safety features includes the installation of an interlock system and

emergency shutdown system if the temperature gets extremely high. The system

is activated at the temperature of 6500C and when it is activated, the block valve

will close the flow of feed; the feed is bypassed and the blow down valve will be

opened to purge the content in the reactor to prevent contain the high

temperature.

Pressure of the reactor

The pressure of the reactor also has to be controlled just as the same priority as

the temperature in the reactor. The feed are of gaseous phase and are easily

influenced by the adjustment of the temperature as well as the pressure with

assumption that the gas is an ideal gas. Furthermore, these two parameters are

essential in the production of the maleic anhydride as the rate of the reaction is

directly dependent on the temperature and pressure of the reactor. The pressure is

controlled by regulating the outlet gas at the top of the reactor. For safety reasons,

pressure relief valve, PSV is installed should the pressure increased tremendously

in the reactor. Accidents may occur if the pressure exceeds the desired value. The

catalyst used is also being control in sense of temperature by measuring and

manipulating the pressure so that the ideal condition could be achieved.

52

TABLE20: REACTOR CONTROL SYSTEM DETAILS

Controlled Variables Manipulated Variables Type of Controller Set Point

Ratio of inlet flow rate Air flow rate Ratio Control

Flow rate ratio =

S8/S6 = 0.017

Temperature of the

reactor

Bypass MS and bypass

feed

High selector with

split range and

cascade control

Temperature: 500 0C

Total bypass feed and

open blow down valve

None (use interlock

and tripping system)

Temperature: 6500C

Temperature of the

reactor (for start-up

reactor)

Start-up heater flow

bypass

Feedback control Temperature: 4000C

Pressure of the reactor Reactor outlet flow rate Feedback Control Pressure: 250 kPa

4.2.5 Heat Exchanger Control System

The purpose of performing a control system for heat exchanger is to maintain the desired

temperature of its outlet stream either by providing heating or cooling utility. There are

two types of heat exchanger control system, depending on whether the heat exchanger

has been integrated or not.

Cooler (Single stream heat exchanger)

There is only one process stream which is experiencing heating or cooling and

the temperature of the stream is controlled by manipulating the flow rate of

utilities stream.

Double stream heat exchanger

The heat exchanger has been integrated. Therefore, there were two process

streams connected to the heat exchanger. Both process streams will experience

either heating or cooling process. Bypass stream is connected from inlet stream to

the outlet stream of the cold stream. Temperature indicator and controller are

53

installed at the outlet of the hot stream and are cascaded with the flow indicator

and controller which is installed at the bypass stream. The temperature of the cold

stream is controlled by manipulating the flow rate of bypass stream.

TABLE 21: COOLER CONTROL SYSTEM DETAILS

Cooler Controlled

Variable

Manipulated

Variable

Type of

Controller Set point

W-6 Reactor effluent

temperature

Cooling water

supply flow rate

Feedback Control Temperature:

125 0C

W-9 Solvent recycle

temperature

Cooling water

supply flow rate


35 0C

TABLE 22: HEAT EXCHANGER CONTROL SYSTEM DETAILS

Heat

Exchanger

Controlled

Variable

Manipulated

Variable

Type of

Controller Set point

W-4 Outlet temperature

of pump

Bypass flow rate Cascade Control

Temperature:

204.2 0C

W-1 Outlet temperature

of W-4

Bypass flow rate Cascade Control

Temperature:

35 0C

4.2.6 Absorber Control System

Absorber is used to absorb the maleic anhydride from other gases. The requirements for

absorber control system are as below:

Level of liquid in the column

The level of liquid at the bottom of the absorber is maintain at desired level by

controlling the outlet flow of rich solvent using feedback controller.

Pressure at top of the column

Feedback control is used to control the operating pressure at the top of the

column to avoid overpressure. The pressure at the top of the absorber is

maintained at desired condition by controlling the outlet flow of off-gases. For

54

safety reasons, pressure relief valve, PSV is installed should the pressure

increased tremendously in the column.

Feed flow rate of the two inlet streams into the absorber

The purpose the control system is to ensure the feed streams is at desired flow

rate. The feed to absorber are outlet of reactor cooler, W-3 and the recycled

solvent dibutyl phthalate from the outlet of heat exchanger, W-4. The ratio for

both streams must be controlled to ensure the absorption for maleic anhydride is

effective. Ratio control is implemented to ensure that sufficient amount of dibutyl

phthalate is fed into the absorber depending on the flow rate ratio set for both

inlet streams.

TABLE 23: GAS ABSORBER, C-301 CONTROL SYSTEM DETAILS

Control

Variable

Manipulated

Variable

Type of

Controller Set Point

Liquid level at

bottom of absorber

Bottom outlet flow rate Feedback Control Level: 80 %

Pressure in the

Absorber

Off-gas outlet flow rate Feedback Control

Pressure:

200kPa

Ratio of inlet flow

Rate

Flow of dibutyl

phthalate

Ratio Control

Flow rate ratio:

S29/S16 =

5.71

4.2.7 Stripper Distillation Column Control System

The control system in the distillation column is important in order to have a sharp

separation between the components in the incoming feed. The control system of

distillation column is controlled based on three purposes:

Material balance control

- The column control system causing the average sum of the product streams

(bottom and top product) to be exactly equal to the average feed rate, keeping

the column in material balance.

- Although the plant is usually designed for a nominal production rate, a design

tolerance is always incorporated because the market condition and demand may

require an increase or decrease from the current state. The control system is then

needed to ensure a smooth and safer transition from the old production level to

the newly desired production level. Its purpose is to direct the control action in

55

such a way as to make the inflows equal to the outflows and achieve a new

steady-state material balance for the plant.

Product quality control

- To maintain the desired concentration of the products at the bottom and the top

of the column.

Satisfaction of constraints.

For safety purposes, satisfactory operation of the column, certain constraints must

be understood and followed, for example:

- The column shall not flood.

- Column pressure drop should be low enough to maintain the efficiency of the

column operation in order to prevent serious weeping or dumping.

- The temperature difference in the reboiler should not exceed the critical

temperature difference.

- Avoid shock loading to the column so that overload of reboiler or condenser

heat-transfer capacity can be avoided.

- Column pressure should not exceed a maximum permissible limit.

-

TABLE 24: DISTILLATION COLUMN CONTROL SYSTEM

Controlled Variable Manipulated Variable Type of Controller Set point

Pressure in the column Top outlet vapor flow

rate

Feedback Control Pressure:

120 kPa

Bottom liquid level Bottom liquid flow

rate

Feedback Control Level: 80 %

Bottom temperature Steam inlet flow

rate


250 0C

Reflux drum level Reflux solution flow

rate

Feedback Control Level: 50 %

Reflux temperature Cooling water

supply flow rate


85 0C

Reflux ratio Reflux flow rate &

MA product flow

rate

Ratio Control

Ratio: 1.8

56

CHAPTER 5: SAFETY AND LOSS PREVENTION

5.1 HAZARD AND OPERABILITY STUDIES (HAZOP)

5.1.1 Introduction to HAZOP

HAZOP, according to Dunn (2009), is a structured procedure intended to proactively

identify equipment modifications and/or safety devices required in order to avoid any

significant danger as a result of equipment failure.HAZOP study focuses on each

pipeline and vessel shown on the respective flow sheet or line diagram. Any possible

deviations from normal operating conditions are studied.As a result, HAZOP study

enables investigation on potential mal-operation, as well as identifies their root causes,

consequences and corrective actions.

5.1.2 Study Nodes Selection

For this HAZOP studies, the selection of study nodes is based on nodes that contain

highly hazardous materials and critical process conditions. With reference to preliminary

hazard analysis conducted in the earlier stage of plant design, it is found that reactor is

one of the high-risk equipment. Due to its high temperature application and variation in

reaction activity, reactor is classified as equipment with critical condition. Furthermore,

the stream contains mixture of gaseous n-butane and air at high temperature, which may

lead to explosion if overpressure.

Therefore, three study nodes connected to reactor (C-1) is selected to be studied in this

HAZOP analysis. The study nodes are shown in the table and figure below.

TABLE 25: STUDY NODES IN HAZOP ANALYSIS

No. Study node

1 Inlet to reactor (C-1) – Stream 11

2 Outlet to reactor (C-1) – Stream 12

3 Inlet of molten salt loop to reactor

57

Reactor

C-1

Stream 11

(Reactant: n-

butane & air)

Stream 12

(Product: MAN,

water, CO, CO2)

Boiler

(For steam

generation)

Molten

salt

inlet

Molten

salt outlet

1 2

3

Further understanding of the process flow can be done by referring to Process Flow

Diagram (PFD) or Process Instrumentation and Control Diagram (P&ID) as attached in

Appendices.

5.1.3 HAZOP Analysis

The following tables (Table 26 - Table 28) illustrate findings from HAZOP analysis.

FIGURE 13: SELECTED STUDY NODES CONNECTED TO REACTOR

58

TABLE 26: STUDY NODE #1

HAZOP STUDY RECORD SHEET PROJECT : MALEIC ANHYDRIDE PLANT

MAJOR UNIT : REACTOR

Date : 20 October 2012

System : MAN Production Study node: Inlet to reactor (C-1) – Stream 11

Item Guide word Deviation Possible consequences Possible causes Safeguard/

Action required

1A1

Flow

More Upsetting process

Uncontrolled reaction

Excessive heat

Excess air

Excess n-butane

Valve fully open

Install high flow alarm

Install dry air control valve after

compressor

Operator to continuously monitor

pipe/valve condition and manually

change valve position

1A2

No No reaction

No product

Pipe rupture

Valve fully closed

Blockage

Install feed flow meter

To be included in biweekly routine

checkup procedure by Inspection Team

1A3

Less Less pressure

Less favorable product.

Pipe leakage

Valve partially closed

Install low flow alarm




59

TABLE 26 (CONTINUED)


Action required

1B1

Pressure More High velocity of

reactant

Overpressure

High temperature

Valve failure

Overheat

Dryer failure

High pressure alarm

Installpressure safety valve (PSV)

Install high temperature alarm

1B2 Less Less reaction

Less favorable product

Leakage

Compressor failure

Insert safety valve

Install low pressure alarm

1C1 Temperature

More Uncontrolled reaction

Mechanical failure

May cause explosion

Pressure increase Install temperature sensor

1C2 Less Less pressure, less

favorable product.

Low pressure Install temperature sensor

1D1 Ignition - Fire, sparks Presence of oxidizing

substance

Temperature rise

Insulation of pipe and equipment

Temperature sensor

60





System : MAN Production Study node: Outlet to reactor (C-1) – Stream 12


Action required

2A1 Flow More Upsetting process

Increase demand for

solvent

Increase in temperature

Uncontrolled reaction

Install high flow alarm

Regular monitoring by Control Team

2A2

No No product Pipe rupture, valve

fully closed, blockage

No reaction







2A3

Less Less product form

Decrease in

temperature

Low reaction rate

Pipe leakage






61



Action required

2B1 Pressure More Low absorption rate Uncontrolled reaction Install pressure safety valve (PSV)

Install high pressure alarm

2B2 Less Less flow rate to the

absorber

Agitate absorption

process

Take longer time

Low reaction rate

Pipe leakage


Operator to monitorpipe/valve

condition


2C1 Temperature More Increase in utility Uncontrolled reaction Install temperature sensor

Install auto-control valve for utility

2C2 Less Less pressure

Take longer time for

absorption process

Low reaction rate Install temperature sensor

62





System : MAN Production Study node: Inlet of molten salt loop to reactor


Action required

3A1

Flow

More More heat absorbed

Temperature in reactor

decrease

Favor undesired

reaction

Valve fully open Install high flow alarm

Operator to manually change valve

position

3A2 No Rise in reactor

temperature

Explosion

May lead to auto-

ignition

Pipe rupture

Valve fully closed

Install safety valve

Pipe/valve operation to be included in

biweekly routine checkup procedure by

Inspection Team




63



Action required

3A3

Less Rise in reactor

temperature

Explosion

May lead to auto-

ignition

Pipe leakage



Install safety valve






3B1 Pressure More System unit rupture

Backflow into solvent

supply

Utility (boiler) failure

Blockage due to crystal

formation

Install pressure safety valve (PSV)

Install high pressure alarm

Boiler operation to be included in


Inspection Team

3B2 Less Reduction in flow rate

of salt

Longer cooling time for

reactor

Large heat loss in

utility (boiler) system

Pipe leakage


Boiler/pipe operation to be included in


Inspection Team

64



Action required

3C1 Temperature More Less effective in

cooling down reactor’s

temperature

Utility (boiler) failure Install temperature sensor



Inspection Team

3C2 Less Heat capacity is higher

More heat is absorbed

Temperature in reactor

decrease

Favor undesired

reaction

Large heat loss in

utility (boiler) system

Install temperature sensor



Inspection Team

65

5.2 PLANT LAYOUT

5.2.1 Site Layout

This Maleic Anhydride production plant will be located in Kidurong Industrial Area, Sabah.

It is planned to occupy area of 350 meter x 300 meter (105,000 m2). The overall site layout

is shown in Appendix. Several factors have been considered in laying out the site. The

process units and ancillary building should be laid out to give the most economical flow of

materials and personnel around the site. In term of safety, process area is located at enough

distance from the place where there are a lot of personnel. Basically, the site layout can be

divided into two parts:

Non-Process area

Process Area

5.2.2 Non-Process Area

As suggested by Kirk-Othmer (1997), non-process area should be located at a distance of at

least, 60 meters from processing area. This is important to avoid any undesired incident due

to explosion or fire from the process zone. Among the buildings or units in the non-process

area are: -

Guard post

Guard posts are located at the entrance of the site. The security checkpoints are important to

ensure unauthorized access into the plant. There are 3 guard posts in this site:

o Main entrance guard post – to control the flow in and out of personnel or cars

between the site and public area.

o Process area guard post – security check to ensure that there is no hazardous or

undesired materials being brought into the process area. It is a common practice in

some places where personnel should have a ‘safety-briefing’ card to be allowed to

enter the process site.

o Contractor’s entrance guard post – contractors will enter the process area at

different entrance with their heavy transport such as crane and lorry.

Administration building

66

Administration office building is sited far away from the process area to avoid any explosion

and fire hazard since this is the place where a lot of personnel involve. It is also near to the

cafeteria and ‘surau’.

Cafeteria

Cafeteria provides meals for the employees and visitors.

Clinic

The location of clinic has been chosen so that it can be reached easily either from the

process area or non-process area. It offers emergency and fast treatment to the injured

employees before being sent to the nearest hospital for further treatment.

5.2.3 Process Area

Process area is the heart of this plant. It is a hazardous area since it deals with a lot of

chemicals. Arrangement of main process site as well as other ancillary buildings was done

carefully. Below are the units and buildings in the Process Area:

Unit 1

This is where the n-butane is being separated from the feed mixture in obtaining a stream of

high content n-butane. It consists of a deisobutanizer column, compressor and mixer.

Unit 2

Oxidation process occur in vapor phase. The feed is contacted with the Vanadium

Phosphorus Oxide catalyst in a packed bed system. MAN is formed as the main product in

the process with the production of carbon monoxide and carbon dioxide as the by product.

Unit 3

MAN purification is a unit to further purify the MAN from other by-products. The main

process goes through the absober Column where MAN is absorbed from the incoming

stream followed by a stripper unit for DBP regeneration to be recycled.

Utilities

This unit will supply cooling water, low pressure steam, plant and instrument air and some

other utilities to the main process unit. Its location is perfectly suitable to give the most

economical run of pipe to and from the process unit.

67

Pump house

The pump house contains pumps used to control the material stream flow between the

process units with the storage farm.

Wastewater Treatment Unit

The wastewater effluent from the process unit will be sent to Wastewater Treatment Unit to

be treated before being released to the environment. It is located adjacent to the main

process unit so that the wastewater effluents from the process units can be channeled to it

without needing long piping to be transferred.

Storage farm

Storage farm consists of some big tanks. These tanks will store the raw material from

supplier before being processed and also stores the product before being exported. Storage

farm is located away from the major processing unit to avoid explosion hazard.

Central control building

All the control valves for the whole process area will be controlled and monitored from this

central control building. Even it is near to the main process area, it still can be considered as

a safe place since it is provided with explosion proof doors and very thick concrete walls. In

case of emergency occurs in the plant, control room will be the assembly point in the

process area.

Fire station

There are two fire stations provided in the process area. One is located near the main process

unit and the other one is placed near the storage farm. These arrangements are made so that

faster action could be taken in case of fire-emergency in these two most hazardous areas.

Operator station

Operator station is adjacent to the central control building.

Laboratory

Quality of feed and product should be taken into considerations. Laboratory is the place

where the sample (both feed and product) is tested and analyzed to determine whether it

meets the specifications or not. All the result will be sent to the control room and some

68

adjustments in controlling will be made, if needed. Thus, the distance between laboratory

and control room is not too far. Laboratory staffs will also perform an analysis regarding

waste of the process before being channeled to nearby environment.

Chemical storage

This unit stores vessels containing chemical substance, lubricants, and catalyst pellet used

for the process. Thus, it is located to the process unit.

Flare Area

Flare is used to burn all excess gas that is emitted from the process units as well as to burn

some of the waste gas from waste treatment area. In our plant, the flare stack is located at

the middle of 100m x 100m area, to give a radius of 50 meters from other sites and

buildings, and meet the statement from Kirk-Othmer (1997), which stated that the minimum

safety range from flare to unit operation and storage farm is in radius of 60 meters.

Warehouse

Warehouse stores all the equipment’s spare parts. It is placed near to the workshop to ease

the maintenance job.

Expansion Site

There are some free areas allocated for the future plant expansion. They occupy enough

space for further expansion, whether for process reaction or producing the plant’s own

utility such as cooling water and steam.

5.2.4 Assembly point

For the whole site in this vinyl chloride plant, there are a few zones that have been identified

to be as assembly area. In the site layout shown in the appendix, all the assembly areas are

represented by small triangles. These are the focal points for every personnel to gather in

case of emergency occur, and the assembly areas are located in both process area and non-

process area. For the non process area, the assembly points are determined to be in front of

the car park, administration building and warehouse. For the process area, the assembly

points are in the control room, near the process area main entrance as well as beside the fire

69

station. However, control room is the best assembly point since it is built with special safety

features with thick concrete wall and explosion-proof door.

5.2.5 Emergency Exit

It is a common practice to have some alternatives way to exit from the chemical plant. In

this site, there are three emergency exits available, two of them are provided in the process

area while the other one is near to the workshop building.

5.3 PLANT LAYOUT CONSIDERATION FACTORS

The economic construction and efficient operation of a process unit will depend on how well

the plant and equipment specified on the process flow-sheet is laid out.

Some of the factors considered are:

Cost

Minimization of construction cost is done by adopting shortest run of connecting pipe

between equipment. The cost is also reduced by having the least amount of structural steel

work. The most important thing is to have an arrangement for best operation and

maintenance.

Operation

Equipment such as valves, sample points and instruments are considered as frequently

attended equipments. They are located not far away from control room, with convenient

positions and heights, to ease the operator’s job. Also, sufficient working and headroom

space are provided to allow easy access to equipments.

Maintenance

When laying out the plant, some considerations were made regarding maintenance work.

For examples:

o Both reactors which use catalysts are located in open space for easiness of

removing or replacing the catalysts.

o Enough space is allocated for heat exchangers for withdrawing the bundles

purposes.

70

o All equipments are accessible to crane/lift truck

o Compressors and pumps are located under cover since they require dismantling

for maintenance

Safety

Among the safety consideration that we have when laying out this plant are:

o Operators have 4 escape routes if anything occurs in the main process unit.

o To minimize fire from spread, flammables handling process units are separated

from each other

o Process vessels with substantial inventories of flammable liquids are located at

grade.

o Elevated areas will have at least one stairway.

o Storage farm which stores the flammable materials are located at safe distance

from the main process area.

o Equipment subject to explosion hazard is set away from occupied buildings and

areas.

Plant expansion

Equipments are arranged by considering future plant expansion, which means it can be

conveniently connected with the new equipment.

TABLE 29: RECOMMENDED MINIMUM CLEARANCE (SOURCE: PABLO AND MARCELL, 1995)

General

1 Primary roads Width 30 ft; Headroom 22 ft; distance from

buildings and process area 10 ft

2 Secondary Roads Width 20 ft; headroom 20 ft; distance from

buildings and process area 5 ft

3 Pump Access Aisle Ways Width 12 ft; headroom 12ft

4 Process Area Main Walkways Width 10 ft; headroom 8 ft

5 Process Areas Service Walkways Width 4 ft; headroom 7 ft

6 Main Pipe Racks Headroom 22 ft

71

7 Secondary Pipe Racks Headroom 15 ft

8 Floor Elevations

The vertical distance between operating

levels must be no less than height of the

tallest process vessel plus 8 ft

Around Hazardous Areas

9 Flare 100 ft

Around Process Equipment

Tank Farms:

10 Between tanks 0.5 diameter

11 From tank to dike wall 5 ft

12 Access around diked area 10 ft

13 Dike capacity largest tank plus 10%

14 Around compressor 10 ft

Between Adjacent Vertical Vessels

15 3 ft diameter 4 ft

16 3-6 ft diameter 6 ft

17 over 6 ft diameter 10 ft

Between Adjacent horizontal Vessels

18 Up to 10 ft diameter up to 10 ft diameter

19 more than 10 ft diameter more than 10 ft diameter

20 Between Horizontal Heat Exchangers 4 ft

21 Between Vertical Heat Exchangers 2 ft

72

CHAPTER 6: WASTE TREATMENT

6.1 INTRODUCTION

Waste is a general problem in chemical plant operation especially in the developing country

where the rules and regulations are very strict regarding the waste disposal. A plant takes

few raw materials to produce products through several stages of processes for the sole

purpose of generating income. But it is not possible to convert all the raw materials into

saleable products thus generating unwanted waste or residual.

The wastewater is essentially the water supply of the community after it has been fouled by

a variety of usage. Wastewater source of generation may be define as a combination of the

liquid or water that carries wastes removed from the residences, institutions and industrial

establishments, together with such groundwater, surface water, and storm water. The

decomposition of untreated accumulation of wastewater will produce large quantities of

malodorous gases. It also contains numerous pathogenic microorganisms that inhabit the

intestinal tract or that may be present in certain industrial waste. Toxic contaminant in

wastewater may lead to fatality of all organisms including aquatic or land inhibited animals

and even human beings. Non-biodegradable waste that accumulated in the food chain is

absorbed into our body system hence leads to serious sickness such as cancer, food

poisoning and others. For these reasons, the treatment of wastewater is necessary in an

industrialized society.

The wastewater treatment involves the primary treatment for the solid removing, such as

screening and sedimentation, the secondary treatment involves biological or chemical

treatment and tertiary treatment for the nutrient removal. The increase in environmental

awareness has pushed the authority to implement strict regulations to limit the release of

proven and potentially hazardous materials by chemical plants.

73

6.2 WASTE MINIMIZATION

A waste is best solved from the source. Minimizing the waste is the most effective way to

counter the waste problem. This includes reducing or recycling the materials that contribute

to waste and resulting in a reduction of total quantity of the waste altogether.

The most preferable way of waste minimization is the prevention of the waste. But

this would also be the least economical and logical way of handling the waste

because in a process plant, to produce a product, there also will be byproducts

created. Byproduct is the main contributor to the unwanted waste.

The other major step in waste minimization is by increasing the efficiency of the

process equipment. Increasing the efficiency means less byproduct or waste will be

produce by the equipment. But for each percentage of efficiency increment, the

tradeoff is the increasing of the overall cost. The cost estimation must be done

thoroughly in order to get the optimum operating conditions for all major equipment

that contributes to producing waste such as reactor, separator and absorber.

The third option which is highly adapted in all process plant is reuse or recycle of

materials. This is the most favorable method in term of cost and the waste

minimization.

The least favorable option of waste handling is disposal of the waste. Disposal of the

waste to the environment must be under the minimum quantity as possible.

6.3 WASTE AUDIT

The discharge from the plant has been identified and there are 3 major wastes. These wastes

are divided into three categories; gaseous waste, liquid waste and solid waste.

The gaseous waste is the off gas released from Absorber (C-2). It contains nitrogen,

carbon dioxide, carbon monoxide and traces of other materials.

The liquid wastes from Deisobutanizer (C-1) contain isobutane. Besides, other

consideration likes dibutyl phthalate discharge or leakage into waste water treatment

from Absorber (C-2) and Stripper (C-3). Also from surface runoff during the raining

74

seasons in the plant area contains traces of other materials. Non-acidic waste is from

the drainage system in the plant area.

Table 30 below shows the streams and type of waste discharged.

TABLE 30: WASTE STREAMS PROPERTIES

Parameter Stream 3 Stream 15 Stream 18

Waste Isobutane Off-gas Water

Type of waste Liquid Gaseous Gaseous

Type of treatment Recycle and

storage

Recycle,

storage, and

incinerate

Recycle to stream 10

Molar flowrate( kmol/hr) 27.50 5798.74 15.27

Temperature (oC) 55.4393 85.7274 85.0

6.4 EFFLUENT DISCHARGE STANDARD AND REQUIREMENTS

In Malaysia, Environmental Quality Act 1974 is the act relating to the prevention,

abatement, control of pollution and enhancement of the environment, and purposes

connected therewith. This parent act, consist of several acts that are enacted from time to

time. This plant is subjected to the Environmental Quality (Scheduled Waste) Regulation

2005 which caters for solid waste storage and disposal and Environmental Quality (Sewage

and Industrial Effluents)Regulation 1979 which caters for the wastewater released.

6.4.1 Purpose of Effluent Standards

The sole purpose of these Effluent Standards for the discharge from wastewater treatment

plants is to control and disposal of effluent to the waters. This will protect the receiving

waters and the living aquatic ecosystems. The public health also must be taken into

75

consideration. These standards are crucial because wastewater discharges have been known

to contribute considerable amount of the biodegradable organic matter and suspended solids

into the receiving waters.

These standards stated the maximum values of waste parameters which must not be

exceeded in order to release the wastewater into the environment. After taking this into

consideration, the design parameters of all the effluent should be less than the standards

mentioned in order to ensure that the waste generated by the plant will fall within the

required degree.

6.4.2 Liquid waste

There are two standards for effluent discharge specified in the Environmental Quality Act

(EQA) 1974:

1. Standard A for discharge upstream of any raw water intake.

2. Standard B for discharge downstream of any raw water intake.

The standards are listed in the Third Schedule of the Environmental Quality Act 1974,

under the Environmental Quality (Sewage and Industrial Effluents) Regulations, 1979,

regulations 8 (1), 8 (2) and 8 (3). An extract of the standards is given below:

TABLE 31: ENVIRONMENTAL QUALITY (SEWAGE AND INDUSTRIAL EFFLUENTS)

REGULATIONS, 1979 (EXTRACT)

Parameters Standard A Standard B

Temperature 40°C 40°C

pH value 6.0-9.00 5.5-9

BOD5 20mg/l 50mg/l

COD 50mg/l 100mg/l

Phenol 0.001mg/l 1.0mg/l

Sulphide 0.50mg/l 0.50mg/l

Oil and Grease Not Detectable 10mg/l

76

TABLE 32: PLANT WASTEWATER AND STANDARD B VALUES OF EQA

Parameter Unit Standard B Plant wastewater

Temperature ˚C 40 40

PH value 5.5-9.0 5.0-9.0

BOD5 at 20˚C ppm 20 10000

COD ppm 50 5000

Phenol mg/l 1.0 >1.0

Oil mg/l 10 >10

6.4.3 Gaseous Waste

The purge gases from the plant process line include n-butane, nitrogen, oxygen, carbon

monoxide, carbon dioxide, water vapor and a little amount of maleic anhydride. The

emission of these gaseous is monitored and controlled to meet the requirements of the

Environmental Quality (Clean Air) Regulations, 1978 under the Malaysian Clean Air

Standards for Dark Smoke and Solid Particle

6.4.4 Solid waste

Under the Environmental Quality (Scheduled Wastes) Regulations 2005, solid waste is

categorized under scheduled wastes and must be treated with outmost care. The appropriate

safety procedure is required in collecting, packaging, storing and transporting the solid

waste. The solid waste is sent to Kualiti Alam Sdn. Bhd. for disposal.

6.5 TREATMENT STRATEGY

TABLE 33: METHOD OF REMOVAL ACCORDING TO WASTE COMPONENT

Wastewater Component Removal Process Level of

Treatment

Oil and Grease (components of

wastewater from other

sources)

Aerated Grit removal

Primary

Suspended Solid Screening, Aerated grit removal

77

Volatile Organic

Compounds:

Maleic anhydride, dibutyl

phthalate

Equalization tank, Clarifier

Secondary

Acid (H2SO4)and

Caustic (NaoH)(used for

pH adjustment)

Clarifier, sludge dewatering

Alum Al2(SO4)3 (used as

chemical coagulant)

Clarifier, sludge dewatering

Sludge Sludge dewatering Unit (centrifuge),

Mechanical Sludge Dewatering (filter

press). Treated sludge shall be sent to

Kualiti Alam Sdn. Bhd. for disposal.

Tertiary

Besides that, wastes of isobutane from stream 3 (S3) will be recycled and stored in the

storage tank for selling.

FIGURE 14: ISOBUTANE STORAGE TANK

78

SECONDARY TREATMENT PRIMARY TREATMENT

TERTIARY TREATMENT

1

SCREENING AND

GRIT REMOVAL

3

BIOLOGICAL

TREATMENT

2

SETTLING AND CHEMICAL

TREATMENT

TREATMENT STAGES

4

PHYSICAL

SEPARATION

6

DISINFECTION

7

NUTRIENT

REMOVAL

5

SCHEDULED

WASTE HANDLING

FIGURE 15: BLOCK DIAGRAM OF WASTEWATER TREATMENT PLANT

79

FIGURE 16: FLOW SHEET OF WASTEWATER TREATMENT PLANT

SECONDARY TREATMENT PRIMARY TREATMENT

TERTIARY TREATMENT

TERTIARY TREATMENT

Untreated

wastewater

Screening

Aerated Grit

Removal

Acid

pH

Stabilizer

Equalization Tank

Alum

Coagulation Tank

Clarifier

Disinfection

biopond

Mechanical

Sludge

Thickener

Sludge

Storage Area

For Disposal

Flowsheet of Wastewater

Treatment Plant

Sludge

dewatering

Caustic

Spent water

Two-Stage

Centrifugal

Separator

SludgeSludge Cake

sea

80

6.6 SCREENING PROCESS

This is the first stage of waste treatment which is the primary treatment stage. The screening

facility purposes are:

To protect downstream equipments and processes by removing debris and other big

particles.

To reduce interference with in plant flow

To minimize blockages in sludge handling facility

6.6.1 Aerated Grit Removal

The grit removal process is also included under the primary treatment stage. The flow

velocity is reduced to allow retention time for larger and heavier particles to settle out. The

grit removal facility purposes are:

To remove grit that will cause problem to pumps and sludge treatment and

dewatering

To remove grease that will cause problem to clarifier

Both grit and grease contain big particles that cannot be broken down by chemical

and biological treatment later.

6.6.2 pH Stabilizer

The pH stabilizer facility falls under the secondary treatment which is the chemical treatment

stage. It consists of multiple mixers to facilitate the mixing of acid and base in order to

stabilize the pH inside the equipment. The purpose of adjusting the pH:

To protect downstream process and equipment from high acidity water that is

corrosive in nature.

Non-neutral pH of wastewater is unacceptable at the biological treatment facility

because it is toxic to the microorganism

6.6.3 Equalization Tank

Secondary treatment stage also includes the equalization tank. The purposes of equalizing the

flow are:

Prevent flow variation for the downstream process

Reduce potential overflow

Reduce hydraulic loading into the downstream process

81

6.6.4 Coagulation Tank

The wastewater must undergo coagulation process before entering the tertiary treatment

which is the biological treatment. The purpose of coagulation process:

Removal of suspended and colloidal solid which cannot be removed by sedimentation.

Reduce soluble organic content in the wastewater consequently reducing the COD

and BOD values.

Removal of metals, phosphorous and colored substances

6.6.5 Clarifier

The first phase of tertiary treatment stage is the clarifier facility. It provided the

sedimentation time which reduces the velocity of wastewater that will allow organic matter in

suspended solid to settle out. The purpose of this facility:

Remove maximum amount of solids

Separate wastewater into sludge and spent water which will be treated separately for

optimum efficiency.

6.6.6 Sludge Dewatering

All treatment processes will generate significant amount of sludge containing inert and non-

biodegradable organic matter. This particular type of sludge must be dispose because it

cannot be treated anymore. Purpose of sludge dewatering facility:

Remove the water contain in the sludge.

Separate the water from sludge

Turned the sludge into sludge cake with low percentage of water.

6.6.7 Mechanical Sludge Thickener

The main purpose of this equipment is to thicken the sludge cake from 1% dry solid to about

6% dry solid content. The thickening equipment used is the gravity belt thickener. To

increase the thickening process, a chemical dosing conditioning also injected into the sludge.

6.6.8 Sludge Storage

The dried sludge cake will be stored for 30 days before disposal to allow sufficient

accumulation of the required quantity of sludge to be disposed. The storage building or

82

structure must have a roof with partly open walls to allow good ventilation. For good conduct

and safety, the storage area should be situated downwind.

6.6.9 Disinfection

The main reason for the disinfection facility is to destruct selective disease causing organism

in the wastewater. Disinfection is important for the wastewater that will be released out into

the open water system. Usage of calcium hypoclorite is the most preferable option because

the typical chlorination type of disinfection is very harmful to operator. Good mixing during

the disinfection stage is important.

6.6.10 Biopond

The biopond facility will provide the last biological treatment before releasing the wastewater

to sea. The wastewater from the disinfection phase will be exposed to microorganism that

will dissolve the remaining organic substances. But the ratio of wastewater from the

disinfection phase must be kept very low to the ratio of wastewater contained in the biopond.

This is to facilitate the dilution process where all the traces of calcium hypoclorite would not

have any affect anymore. This is crucial to prevent toxicity to microorganism in the biopond.

The holding period of treated wastewater in the biopond will range from one to two week

before releasing to receiving water. So the volume of the biopond will have to be bigger.

6.7 GAS TREATMENT

When making contact with the gaseous waste, there are few methods available for the

treatment. The methods are incineration, condensation, adsorption and flaring. All the

treatment method has been studied and the limitation of each method is taken into account

when choosing the best method to be used to treat the gaseous waste. The limitation as shown

in the table:

TABLE 34: SUMMARY OF THE LIMITATIONS FOR THE GASEOUS TREATMENT STRATEGY

Treatment

Method Limitation

Control by

flaring

More economical since the gaseous wastes is not going to be recover

or as the result of intermittent, uncertain or emergency process

operations

The combustion of VOCs will produce harmless or much less

83

harmful substances since the flare temperature will be operating

below 1000 K to avoid the formation of NOx

Flare will be injected with steam to enhance mixing so that the

combustion process will be as complete as practical

Control by

adsorption

Normally used for large VOCs content stream for recovery

Not economical for small stream

Activated carbon is a very effective adsorbent in removing VOCs,

but quite expensive

Control by

incineration

Not practical for low gas flow

The N2 presents in the gas stream may enter the atmosphere partly as

N2, NO or NO2

Incomplete combustion of gas stream can produce an exhaust gas

that is more harmful than the input gas

Additional fuel is require to burn the VOCs if the total mass fraction

of VOCs too small

If a heat exchanger is installed to lower the cost of fuel, the cost of

the heat exchanger itself is high and may lead to corrosion problem

If catalytic incinerator is applied, the fuel cost is greatly reduced and

the operating temperature is low. However, the catalyst will

significantly increase the operating cost

Control by

condensation

Normally used for large VOCs content stream for recovery purpose

This method is not economical for small stream

The temperature is low enough that ordinary one-stage refrigerators

cannot be used

Often the temperatures required for high removal efficiency are

below the freezing temperature of the material being removed so that

the material freezes on the cooling coils, requiring frequent

defrosting

If the gas being treated contains significant amounts of water vapor,

it will condense and freeze on the cooling coil, this requiring

frequent defrosting

84

After considering all the options, the flaring method has been chosen because it fulfills the

entire requirement and suitable to treat the gaseous waste discharge at the off gas line. Its

systems are the satisfactory provision in the design and operation of the basic requirements

for combustion.

These gases must be release to maintain the operating pressure of the equipment in the

process plant from daily operation and also during the emergency shutdown. The main

control that needs to be maintained along the flaring process is the control of proper steam

flow. This is because with proper steam flow, smokeless operation can be maintained at all

conditions of gas flow, which provide an almost complete combustion of gaseous. To

conform to the Environmental Quality (Clean Air) Regulations 1978, a filter should be

installed at the stack gas tip before releasing the gas. Gas quality monitoring system should

also be installed in order to ensure that the gas release is within the acceptable range.

Besides that, the nitrogen gaseous that was produced at stream 15 (S15) will be separated by

using nitrogen separator and will be used as process blanket. The other component such as

isobutane will be recycled and kept in the storage tank for selling.

FIGURE 17: NITROGEN SEPARATOR

For the gas waste from the stream 18 (S18) will also be channeled to the flare for combustion.

85

FIGURE 18: WASTE OF STREAM 18 (S18)

6.8 SOLID HANDLING TREATMENT

Solid wastes of the plant are generated from different processes, chemical handling

operations as well as from wastewater treatment, which consists of hazardous and non-

hazardous wastes. Hazardous waste is defined as any solid waste listed as hazardous or

possesses one or more hazardous characteristics as defined in federal waste regulations. Its

effect can last for very long periods of time. Major solid wastes are typically in the form of

sludge, scrap and spent process catalyst and it’s divided into three; scheduled waste, recycled

waste and domestic waste.

There are a few treatment methods in handling the solid waste and it have been summarized

in Table 35 below:

TABLE 35: DISPOSAL METHODS OF SOLID WASTE

Solid Waste Disposal/Treatment Method

Tank bottom sludge (from Wastewater

Plant)

Sent to KualitiAlam

Empty Drums Returned to supplier

Wood, metal scrap/various valuables like

empty drums

Miscellaneous (paper, plastic, domestic

waste)

Sold to contractors

Disposed off through a Contractor

86

6.9 SCHEDULED WASTE

Scheduled wastes, one of the solid wastes produced in the plant is a small percentage of

hazardous waste, which has been regarded for a long time as intractable, or difficult to safely

dispose of, without special technologies and facilities. It is also can be defined as a material

or article containing a chemical, or mixture of chemicals, exceeding the threshold

concentration and threshold quantity which are:

organic in nature

resistant to degradation by chemical, physical or biological means

toxic to humans, animals, vegetation or aquatic life

bio-accumulative in humans, flora and fauna

According to Environmental Quality (Scheduled Wastes) Regulations, 1989, solid waste is

categorized under scheduled wastes, and must be treated appropriately. It is the duty of the

plant management to adopt safety procedure in collecting, packaging, inventorying and

transporting the solid waste to suitable parties before further treatment. Sludge is turned into

sludge cake to reduce the weight and for ease of loading into plastic lined drums before being

transported.

87

CHAPTER 7: PROJECT ECONOMICS AND COST ESTIMATION

7.1 INTRODUCTION

The economic evaluation of a plant is important in determining the profitability of a

plant in generating profit. Therefore, before building any plant, the design engineer needs to

decide between alternative designs to be implemented as well as the overall plant economics.

In evaluating the project economics, estimates of investment and equipment costs are

required. Before the final process design starts, company management normally becomes

involved to decide if significant capital funds will be committed to the project or not.

7.1.1 Capital Investment

The estimation of Total Capital Investment and Total Product Cost of the project are

determined by using the methods suggested by Peters and Timmerhaus .Equipment

purchasing amount are determined by using method by Warren D.Seider, J.D Seader and

Daniel R.Lewin.

The capital needed to supply the required manufacturing and plant facilities is called fixed

capital investment (FCI) while that necessary for the operation of plant is termed the working

capital (WC). Start-up Cost (SC) is the cost required at first once the process of the plant is

started. Thus the sum of the fixed capital investment, working capital start-up cost is known

as the total capital investment (TCI). Furthermore, cash flow and discounted cash flow are

also constructed in determining the Pay-Back Period as well as Net Present Value for the

project.

Fixed capital investment can be divided into two that are manufacturing fixed capital

investment (direct cost) and non-manufacturing fixed capital investment (indirect cost).

Basically, FCI depends on the total equipments cost available in the plant multiply with a

factor that varies according to what type of cost it represents. Meanwhile, working capital is

the additional investment needed, over and above the fixed capital, to start the plant up and

operate it to the point when income is earned.

The calculation made follows the Douglas’s approach method

The interest rate for plant operation is 10% per annum

Project life-cycle will be 15 years

Plant operates at normal annual operation period which is 330 days

88

7.1.2 Total Equipment Cost (TEC)

Capital cost estimate for chemical process plants can be based on purchase cost estimation of

the major equipment items. The equipment cost will be used along with factors for estimating

other relevant costs(Sinnott.2005).

TABLE 36: TOTAL EQUIPMENT COST

Equipments Cost Quantity Total Cost (USD) Total Cost

(RM)

Expander 1000000 1 1000000 3059039.462

Centrifugal Separator 1340000 1 1340000 4099112.879

Butane Tank 160000 1 160000 489446.3139

Cooler 1 59500 1 59500 182012.848

Cooler 2 67000 1 67000 204955.6439

Heat Exchanger 1 245000 1 245000 749464.6681

Heat Exchanger 2 116000 1 116000 354848.5775

Heat Exchanger 3 134500 1 134500 411440.8076

Absorber 1580000 1 1580000 4833282.349

Recycle Pump 13000 3 39000 119302.539

Deisobutanizer 570000 1 570000 1743652.493

Stripper 343000 1 343000 1049250.535

MAN Tank 238000 1 238000 728051.3919

Reaction Reactor (incl catalyst) 620000 1 620000 1896604.466

Mixer 160000 1 160000 489446.3139

TOTAL EQUIPMENT COST 20409911.29

In order to estimate the capital cost for chemical process plant, the factorial method of cost

estimation is used. To make a more accurate estimate, the cost factors that are compounded

into the ‘Lang factor’ are considered individually.

7.1.3 Fixed Capital Investment

The direct cost and indirect cost items incurred in the construction that are used to

calculate Fixed Capital Investment of a plant are as such :

FCI = Total Equipment Cost * Lang’s Factor

= RM 71965347.20 (in 2004)

89

Fixed Capital Investment (FCI) = FCI (2004) * (CEPCI 2012/CEPCI2004)

= 94889923.13

Total Capital Investment = Working Capital (15% FCI) + S/Up Cost (10% FCI) + FCI

= RM 118 612 403.90

7.1.4 Estimation of Total Operating Cost

All expenses directly connected with the manufacturing operation or the physical equipment

of a process plant is included in the operating costs.

Raw Material

98838109.36

Utilities Cold Utilities

25192299

Maintenance Cost 2% of FCI

1897798.463

Operating Supplies 10% of Maintenance Cost

189779.8463

Operating Labour

720000

Management Personnel 10% of Operating Labour

72000

Laboratory Charges 5% of Operating Labour

36000

Patent and Royalties 1% of Total Expenses

1269459.867

TOTAL VARIABLE COST 128215446.5

Local tax 1% of FCI

948899.2313

Insurance 0.4% of FCI

379559.6925

FIXED CHARGES 1328458.924

PLANT OVERHEAD 50% (Maintenance + Labour + Supervision) 1344899.231

TOTAL MANUFACTURING COST 130888804.7

Administrative Cost 15% (Maintenance + Labour + Supervision) 403469.7694

Distribution and Selling 10% of TMC

13088880.47

R&D 5% of TMC

6544440.235

TOTAL GENERAL EXPENSES 20036790.47

TOTAL OPERATING COST = Total Manufacturing Cost + General Expenses

= RM 150,925,595.20

7.1.5 Gross Profit

For the case of this plant, the revenue comes from solely selling of MAN as shown below:

Profit = Total Sale – Total Operating Cost

= (RM 7 944.33/ton x 50000tonne/yr) – 150,925,595.20

= RM 177,395,904.80/year

90

7.2 PROFITABILITY ANALYSIS

In determining the economic attractiveness of a project, it is important to based decision three

important economic parameters which are Investment Rate of Return (IRR), Net Present

Value (NPV) and Pay Back Period (PBP). Several assumptions are made in the economic

analysis of this maleic anhydride acid plant. The assumptions are as follows:

The plant has a project plant life of 15 years.

The plant construction period is 3 years before commencing production. Hence,

the total investment cost is distributed evenly between the 3 years.

Interest rate is 15%

Local Taxes is assumed to be at 10% annually.

7.2.1 Start-up Period

The plant will start up in year 4. The plant construction assumed to be last for 3 years.

TABLE 37: CAPITAL INVESTMENT FOR START-UP PERIOD

Start up period of 3 years

Year 0 Equipment & Design - 29602641.93

Year 1 (Direct Cost – Year 1 Cost)/2 -19895528

Year 2 As year 1 -19895528

Year 3 Indirect Cost + S/up cost -26294129.60

Total -95687827.53

7.2.2 Depreciation

When government taxing comes into place, depreciation becomes important to aid the

plant from balancing tax payment to equipment wear. In this project, depreciation per annum

can be computed as.

millionRM

RMRM

n

SVBDt

7.7

15

)394889923.103.0(9118612403.

15

)Investment Capital Fixed0.03-(B

91

life edepreciabl expected n

Investment Capital Fixed0.03x value,salvage estimated SV

investment total B

chargeon depreciati annualD

n)1,2......,(tyear t

where

t

7.2.3 Cash Flow Estimation

Here, the net cash flow in each year of the project is brought to its “present worth” at the start

of the project by discounting it at some chosen compound interest.

years projects, of life t

cent/100per rate)est rate(interdiscount r

nyear in flowcash net estimated NFW where,

11

tn

nnr)(

NFWt of projecTotal NPW

A discount rate of 15% is used

From the investment as Table 37 and also annual gross earning, cash flow diagram is as

follow, to obtain the payback period.

FIGURE 19: CASH FLOW DIAGRAM

92

7.2.4 Net Present Worth

TABLE 38: CUMULATIVE CASH FLOW

r (%) NPW (Cumulative Cash Flow at years 15) (RM)

10 630341893

20 255582162

30 102887451

40 33344914

50 -1062648

From the net present worth calculated by varying the discount rate, it will reach negative

when the rate is in between 40-50%, this is higher than MARR, thus project is feasible.

7.2.5 Internal Rate of return

7.2.6 Rate of Return (ROR) Estimation

The simplest method is to base the ROR on the average income over the life of the project

and the original investment.

%43.22%10091118612403.15

399036617

100

per centnvestmentoriginal iojectLife of pr

ctd of projeflow at en net cash CumulativeROR

Expected ROR (Rate of Return) must at least meet or exceed the MARR (Minimum

Attractive Rate of Return) of 15%. Since, the rate of return of the project is 22.43%, which is

more than 15%, the project is worth investing.

7.2.7 Net Present Value or Worth (NPV) Estimation

years projects, of life t

cent/100per return of rate flowcash discountedr

nyear in flowcash net estimated NFW

where,

11'

tn

nn)r(

NFWNPW

NPV calculated is RM 399 million

93

7.2.8 Pay Back Time

Pay Back Period the time that must elapse after startup until cumulative undiscounted cash

flow repays fixed capital investment. For this project, it is 5 years.

FIGURE 20: PAYBACK TIME

7.3 DISCUSSIONS

From the economic analysis done, the plant will need a capital investment of RM RM118.612

million. An internal rate of return (IRR) of 49 % and a net present value (NPW) of RM 399

million is attainable for a project plant life of 15 years with a payback time of 5 years after

plant startup. In addition, annual sales will generate an income of RM 177.395million

annually. In fact the return on investment is 22.43%, which is higher than MARR, hence, this

indicates that the plant is economically viable and economically attractive. The economic

evaluation conducted on the maleic anhydride plant at this stage serves only as a very crude

estimation.

Furthermore, the correlations taken from different references may give different value and

methods in estimating the plants cost. In addition, the assumptions made may also be invalid,

considering the fact that economic environment is very sensitive to the global environment

and may subject to changes from time to time. Apart from that, it is very difficult to predict

the actual annual cash flow since the reliability of the plant equipments is not known. Hence,

the actual investment cost may be larger than the predicted figure. For improvement, a

concise economic evaluation should be carry out by considering all the factors mentioned

above to obtain the best economic potential for the MAN plant.

-5E+08

0

500000000

1E+09

1.5E+09

2E+09

0 5 10 15

Cu

mu

lati

ve C

ash

Flo

w (

RM

)

Year

Payback Period

94

CHAPTER 8: CONCLUSION & RECOMMENDATION

8.1 CONCLUSION

The overall design project for the production of Maleic Anhydride meets the desired

requirements and objectives. The production of 50,000 metric tonne per year of Maleic

Anhydride has a bright future especially in the South East Asia region. From the feasibility

study carried out, the future growth of Maleic Anhydride demand in the South East Asia

market is optimistic, 4.5 % per year growth on Maleic Anhydride consumption is forecasted

until year 2009.

The proposed plant is situated at Kidurong Industrial Estate which is feasible, economically

and environmentally. Moreover, the utilities supply such as cooling water supply, deionized

water, electricity and steam supply required for the process can be easily obtained.

The process chosen for the production of Maleic Anhydride is the catalytic oxidization of n-

butane. Heuristics approach has been applied in identifying the appropriate design. For the

process synthesis and flow sheeting, base case material and energy balance together with

process simulation has been performed both by manual calculation and iCON simulator.

Detailed equipment process design and mechanical engineering design of all major

equipment has been performed. A highly integrated heat exchanger network and process

control system is also included to the proposed plant to ensure the profitability of the plant.

In responding to the environmental responsibility, the plant has been designed to achieve the

target of waste minimization and cost minimization. The unwanted side product is being

combusted and well treated to ensure the emission coming out from the plant has met the

Malaysian government Environment Quality Act, 1974. On the safety aspect, HAZOP study

has been conducted to identify the occurrence of operational problems and providing

necessary resolution. A general safety study includes personal safety, emergency

management, Standard Operation Procedures (SOP) and plant start up and shut down

procedures were documented in this report as well.

95

As for the economic evaluation of the process plant, the cost of the plant is calculated by

using detailed factorial method. The total capital investment of the plant is approximately RM

118 million. The Rate of Return (ROR) is 22.43 % which is higher than Minimum Attractive

Rate of Return (MARR) 15 %, therefore the project is worth investing. The payback period is

5 years after plant start-up which is within feasible period of time.

Finally, it can be concluded that the construction of a 50,000 metric tonne per year of Maleic

Anhydride production plant in Kidurong, Bintulu is technically feasible and economically

attractive.

8.2 RECOMMENDATION

The final year design project has been useful in cultivating and enhancing the skills and

knowledge at hand. As final year students, the experience gained throughout the process of

this project has given the opportunity to actually design a real processing plant has increase

our understanding in the chemical engineering field. Besides that, other skills were also

developed in the process such as communication skills, management skill, and team work.

However, we find that there few areas that needs improvements and perhaps a new approach

in solving some of the problems faced.

Firstly, we recommend that the PDP committee provide standardized values of key elements

such as the feeds prices. We have different values of feed because taking it from different

sources. So, a standardized value is appropriate to accommodate the student with a good

reference. Secondly, further research must be done on isomeric conversion technology in

order to convert isomers back to its normal state. This is important to reduce the amount of

byproduct produced from the process. Thirdly, we propose that students should be provided

easier access to the labs to use engineering software such as HYSYS and AutoCAD and the

department should provide a proper manual as guidance. Finally, a complete and clear

guidance should be provided to the student and without further amendment. Students are

facing difficulty to cope with sudden changes and added requirements made by the

coordinator due to the short time frame to finish it.

We hope that these recommendations will be considered and useful by the PDP committee to

improve the PDP project handled by the student in the future.

96

REFERENCES

(1992). Maleic Anhydride World Survey. London: Tecnon(U.K.) Ltd.

Maleic Anhydride. (2011, November). Retrieved June 2, 2012, from IHS Chemical:

http://www.ihs.com/products/chemical/planning/ceh/maleic-anyhydride.aspx

Maleic Anhydride. (2011). Retrieved June 4, 2012, from Thirumalai Chemicals Ltd.:

http://www.thirumalaichemicals.com/maleic.html

AP-42, CH 6.14: Maleic Anhydride. (n.d.). Retrieved June 1, 2012, from

www.epa.gov/ttnchie1/ap42/ch06/final/c06s14.pdf

BDA. (2010, April 10). Official Website of Bintulu Development Authority. Retrieved June

11, 2012, from Bintulu Development Authority Official Website:

http://www.bda.gov.my/modules/web/index.php?menu_id=0&sub_id=1

Fogler, H. S. (2006). Elements of Chemical Reaction Engineering (4th ed.). New Jersey:

Pearson Education Inc.

Ishak, M. (2011, September 1). Bintulu Analysis. The Report, SARAWAK 2011, 34-43.

Jose, S. (2008, November 3). World Maleic Anhydride Market to Reach 2.0 Million Metric

Tons by 2012, According to New Report by Global Industry Analysts. Retrieved June

4, 2012, from PRWeb:

http://www.prweb.com/releases/maleic_anhydride/butanediol/prweb1553754.htm

KKIP. (1995, November 2). Investing in KKIP. Retrieved June 12, 2012, from Kota Kinabalu

Industrial Park: http://www.sabah.com.my/kkip/inv.html

Lohbeck, K., Haferkorn, H., Fuhrmann, W., & Fedtke, N. (2005). Maleic and Fumaric Acids.

In Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH.

Pinch Analysis. (n.d.). Retrieved August 25, 2012, from KBC Nextgen Performance:

http://www.kbcat.com/?id=51&fm=search&searchText=pinch%20analysis

Production of Maleic Anhydride. (n.d.). Retrieved June 6, 2012, from

www.che.cemr.wvu.edu/publications/projects/large.../maleic.PDF

Production of Phthalate Anhydride from O-xylene. (n.d.). Retrieved June 7, 2012, from

www.che.cemr.wvu.edu/publications/.../phthalic2/phthalic2-b.pdf

97

Sarawak Government. (2010, April 20). Sarawak Government Portal | Investment Incentives.

Retrieved June 11, 2012, from The Official Portal of Sarawak Government:

http://www.sarawak.gov.my/en/investors/investment-incentives

Silla, H. (2003). Chemical Process Engineering Design and Economics. USA: Marcel

Dekker.

Timbang, M. (2007, March 2). Bintulu - Wikipedia, the free encyclopedia. Retrieved June 11,

2012, from Wikipedia: http://en.wikipedia.org/wiki/Bintulu

Timothy R. Felthouse, J. C.-J. (2001, April 26). Department of Chemistry. Retrieved June 2,

2012, from University of South Alabama:

http://www.southalabama.edu/chemistry/barletta/felthouse.pdf

Tissue, B. M. (2000). The Chemistry Hypermedia Project. Retrieved August 1, 2012, from

CHP website: http://www.files.chem.vt.edu/chem-ed/sep/gc/gc.html

Town and Regional Planning Department Sabah. (2011, January 1). Land Zoned for Industry

Sabah. Retrieved June 12, 2012, from Jabatan Perancang Wilayah dan Negeri Sabah:

http://www.townplanning.sabah.gov.my/

US EPA. (2011, July 8). Oil and Gas Production Waste | Radiation Protection | US EPA.

Retrieved July 25, 2012, from US Environmental Protection Agency:

http://www.epa.gov/rpdweb00/tenorm/oilandgas.html#scale

Woril Turner Dudley, V. K. (2012, January 3). Maleic Anhydride - Process Design.

Retrieved June 2, 2012, from Scribd.: http://www.scribd.com/doc/76994917/Maleic-

Anhydride-Process-Design#

98

APPENDICES

APPENDIX 1: PROCESS FLOW DIAGRAM OF MAN PLANT .................................................I

APPENDIX 2: P&ID OF MAN PRODUCTION PLANT ............................................................ II

APPENDIX 3: CRITERIAS FOR EACH SITE PLANNED ...................................................... III

APPENDIX 4: MASS BALANCE CALCULATION (DEISOBUTANIZER) ............................... V

APPENDIX 5: MASS ENERGY BALANCE (MIXER) ............................................................. IX

APPENDIX 6: MASS ENERGY BALANCE (REACTOR) ......................................................... X

APPENDIX 7: MASS ENERGY BALANCE (ABSORBER) ..................................................... XII

APPENDIX 8: MASS ENERGY BALANCE (STRIPPER) ..................................................... XIII

APPENDIX 9: CP VALUE FOR ENERGY BALANCE CALCULATION ............................ XVII

APPENDIX 10: DRAFT OF PLANT LAYOUT ..................................................................... XIX

i

APPENDIX 1: PROCESS FLOW DIAGRAM OF MAN PLANT

ii

APPENDIX 2: P&ID OF MAN PRODUCTION PLANT

iii

APPENDIX 3: CRITERIAS FOR EACH SITE PLANNED

Selection Criteria Kidurong Industrial Area

Kota Kinabalu Industrial

Park

PasirGudang Industrial

Estate

Kertih Integrated

Petrochemical Complex

PengerangIntergrated

Petroleum Complex

Location 20 km from Bintulu Town 25 km from KK 36km from Johor Bharu 5 km from Paka and 9.6 km

from Kemaman 42km from Johor Bharu

Type of industry Light & Medium Any compatible Light, Medium & Heavy Petrochemical, Chemical and

General Petrochemical and refinery

Preferred

Petrochemical and gas Food

Petrochemical

Timber-based Timber-based

Plantation and Agro Plantation-based

Energy Intensive

Area available 97.3 hectare 7.05 acres 430 acres 100 acres 22, 500 acres

Land price(per m2) RM77.42 RM129.17 RM 86.08 – 236.72 RM20 RM64.58-RM86.11

Raw material

Optimal, Kerteh PETRONAS Gas Berhad

PETRONAS Rapid (LNG

Regasification Plant) Supplier Amoco Chemicals, Gebeng

Power Supply SESCO’S Combined Cycle

Power Plant (132MW)

KKIP Power SdnBhd Sultan Iskandar Power

Station (644 MW)

TasikKenyir Hydroelectric

Dam Sultan Iskandar Power

Station (TNB)

(300MW) (400MW)

Bakun Hydroelectricity

Power Project (2400MW)

Powertron Resources S/B IPP YTL Power Generation

Sdn. Bhd. IPP YTL (600 MW)

PasirGudang Power Station

(YTL Power International

Bhd) (120MW)

Sarawak Power Generation

Plant (220MW)

Sabah Electricity SdbBhd

Paka Power plant PETRONAS Power Plant

(future planning) (293MW)

CUF Kerteh

Water Supply

Bintulu Water Supply

Treatment Plant

Diversified Water Resources

S/B Loji Air Sungai Layang Bukit Sah SAJ Holding SdnBhd

Syarikat Air Johor Sungai Cherol

Future investment on water

supply project

Loji Air Sungai Buluh Sungai Kemasik

Port Facilities Bintulu Deepwater Port Sepanggar Bay Port PasirGudang Port Kerteh Port, TanjungBerhala

Port, Kuala Terengganu port

Pengerang Petroleum

Terminal

TanjungLangsat Petroleum

Terminal

Airport Bintulu Airport Kota Kinabalu International

Airport

Senai International Airport,

Johor and Changi

International Airport,

Singapore

Sultan Mahmud Airport,

Kuala Terengganu and Sultan

Ahmad Shah Airport,

Kuantan

Senai International Airport,

Johor and Changi

International Airport,

Singapore

Railway facilities - - Singapore and North Kuantan-Kerteh Railway KTM Singapore-North

iv

Peninsular Malaysia peninsular route

Roadways

Pan-Borneo Highway KK-Sulaman Road Main road to Singapore Kuala Terengganu-Kuantan- Second Link Expressway

KK West Coast Parkway PLUS Highway Karak Highway Senai-Desaru Expressway

Federal Route 500

North-South Highway

Incentives

Pioneer Status Pioneer Status

Infrastructure Allowance. a flat corporate tax rate of 3%

of chargeable income; 5-years 70% tax exemption

on statutory income

5-years corporate tax on 15%

of statutory income Incentive for exports

Investment Tax Allowance Investment Tax Allowance

Incentives for research

development

Five-year exemption on

import duty.

100% exemption on director

fees paid to non-Malaysian

director;

Allowance of 100% in respect

of qualifying capital

expenditure incurred




Reinvestment Allowance Infrastructure Allowance Exemption from import duty

on direct raw

materials/components

5 % discount on monthly

electrical bills for first 2

years.

50% exemption on gross

employment income for non-

Malaysian professional

traders;




100% infrastructure

allowance on qualifying

expenditures

Incentives for High Tech

Industries

Land Incentives by State

Government

Pioneer Status and


and Reinvestment Allowance.

25-38 % exemption on daily

water cost for 4545 m3 of

water for

tax exemption of stamp

duties on documentation

Rebate on industrial land Free Infrastructures Incentives for high tech

industries and for training

tariff protection

Pioneer Status and


and Reinvestment Allowance.

tax exemption on dividends

received by or from the LITC

companies.

Incentives for high tech

industries

Local people 200 000 peoples 200 000 peoples 1500 000 peoples 200 000 peoples 40,000 people

(Below 40 years old)

Waste water management

KualitiAlamSdnBhd, Bukit

Nenas, Negeri Sembilan

Effluent Treatment Plant of

CUF

KualitiAlamSdnBhd, Bukit

Nenas, Negeri Sembilan KualitiAlamSdnBhd

Indah Water Konsortium

v

APPENDIX 4: MASS BALANCE CALCULATION (DEISOBUTANIZER)

Example Mass Balance Calculation for Deisobutanizer distillation column

Calculation of component distribution using Hengstebeck Method

Calculation of saturation pressure of each component using the equation below:

The operating condition of the column is 850C and 11atm.

The light key (LK) is isobutene distilled in the top at 55% and the heavy key (HK) is n-

butane distilled at the bottom at 99.9%

The feed flow rate is 9700 kg/h with the pre-specified feed composition.

Example calculation using propane:

Partial pressure, Pi = Psat(x) = 3487.14(0.02) = 69.74 kPa

Volatility, Ki = Pi/PT = 69.74/1114.575 = 0.063

Relative volatility, α = Ki/Khk = 0.063/0.7 = 0.09

Cmb

dij

i

i

loglog

vi

The calculation of other component is done below:

MW Component Mass

fraction

Mass flow rate Mole flow rate Mole Fraction Psat Pi Ki

44.096 Propane 0.0154 149.38 3.3876089 0.02023 3487.1483 70.54017 0.06328885

58.122 Isobutene 0.295 2861.5 49.232649 0.29399 1535.3106 451.35917 0.404960784

58.122 n-butane 0.677 6566.9 112.98476 0.67467 1162.3554 784.20863 0.703594309

56.106 Isobutene 0.0013 12.61 0.2247531 0.00134 1404.7017 1.8852229 0.001691428

56.106 1-butene 0.002 19.4 0.3457741 0.00206 1367.9095 2.8243767 0.002534039

72.149 Neopentane 0.0011 10.67 0.1478884 0.00088 881.58433 0.7785218 0.000698492

72.149 iso-pentane 0.0077 74.69 1.0352188 0.00618 524.91238 3.2448288 0.00291127

72.149 n-pentane 0.0008 7.76 0.1075552 0.00064 426.31218 0.2737991 0.000245653

Component Α log α

Propane 0.08995077 -1.0459951

Isobutene 0.57556006 -0.2399093

n-butane 1 0

Isobutene 0.00240398 -2.6190689

1-butene 0.00360156 -2.443509

Neopentane 0.00099275 -3.0031608

iso-pentane 0.00413771 -2.3832398

n-pentane 0.00034914 -3.4569996

vii

A graph of log d/b and log α is plotted for the LK and HK as reference for finding the

composition of the other components.

Example calculation for isobutene (LK):

d = 0.55(49.23) = 27.08

b = 0.45(49.23) = 22.15

d/b = 27.08/22.15 = 1.22

log d/b = 0.087

log α = -0.24

Component LK HK

F 49.23265 112.9847562

D 27.07796 0.112984756

B 22.15469 112.8717714

d/b 1.222222 0.001001001

lg d/b 0.08715 -2.99956549

lg α -0.23991 0

From the graph above, m = -12.866 and c = -2.9996.

The d/b for other components are calculated.

Example calculation for propane:

y = -12.866x - 2.9996

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

-0.3 -0.25 -0.2 -0.15 -0.1 -0.05 0

log

d/b

log α

log d/b vs log α

viii

Mol fraction going to bottom from feed, xbi = 1/(d/b+1) = 0

Mol fraction going to distillate from feed, xdi = 1- xbi = 1

Mol flow rate component in bottom, L = xbi(mol flow rate component) = 0

Mol flow rate component in distillate, V = xdi(mol flow rate component) = 1(3.388) = 3.388

mol/hr

Component log α log di/bi di/bi Xbi xdi V L

propane -1.0459951 10.4581731 2.8719E+10 3.482E-11 1 3.38760885 1.1796E-10

isobutane -0.2399093 0.08707368 1.22200697 0.45004359 0.54995641 27.0758105 22.156838

n-butane 0 -2.9996 0.00100092 0.99900008 0.00099992 0.11297579 112.87178

isobutene -2.6190689 30.6973407 4.9813E+30 2.0075E-31 1 0.22475315 4.512E-32

1-butene -2.443509 28.4385868 2.7453E+28 3.6426E-29 1 0.34577407 1.2595E-29

neopentane -3.0031608 35.6390672 4.3558E+35 2.2958E-36 1 0.1478884 3.3952E-37

iso-pentane -2.3832398 27.6631637 4.6043E+27 2.1719E-28 1 1.03521878 2.2484E-28

n-pentane -3.4569996 41.4781574 3.0072E+41 3.3254E-42 1 0.1075552 3.5766E-43

ix

APPENDIX 5: MASS ENERGY BALANCE (MIXER)

Example Mass Balance Calculation for mixer

Input = output

Stream 4 + stream 6 = stream 7

Component Steam 4

(kg/h)

Steam 6

(kg/h)

Steam 7

(kg/h)

Isobutane 1287.80 0 1287.80

n-butane 6560.33 0 6560.33

Oxygen 0.00 39730.8667 39730.87

Water 0.00 3195.31948 3195.32

Nitrogen 0.00 130843.358 130843.36

Stream 6 is the air feed with a 65% humidity. Thus, from the Psychometer chart from

appendix figure 5.1

H=0.018kg water/kg dry air

=0.03 kgmol water/kgmol dry air

The oxygen feed must be below 0.0181 mol % which is below the flammability limit of n-

butane mixture.

By using excel, the required amount of oxygen is 39730 kg/h

Total Nitrogen = 39730(0.79/0.21) = 130843.358 kg/h

Total air = 42926.187 kg/h = 5912.33 kgmole/h

Total water with the air = 5912.33(0.03) = 177.37 kgmole/h = 130843.358 kg/hr

4

6

7

x

APPENDIX 6: MASS ENERGY BALANCE (REACTOR)

Example Mass Balance Calculation for Reactor

C4H10 + 3.5O2 C4H2O3 + 4H2O

C4H10 + 5.5O2 2CO + 2CO2 + 5H2O

Using extent of reaction method, with the assumption of pure n-butane feed and oxygen feed

is used for the sake of simplicity.

The actual process uses a mixture of n-butane feed with air at 65% humidity used as the

source of oxygen. The water entering together with air is calculated and the ratio of air to

feed is kept at a ratio of 0.017% which is below the flammability limit.

The following initial are used for reference:

b = n-butane, f = final, i = initial, MAN = maleic anhydride, CO = carbon monoxide, CO2 =

carbon dioxide, O2 = oxygen

Production:

No. of moles for n-butane:

No. of moles for MAN:

No. of moles for carbon monoxide:

No. of moles for carbon dioxide:

No. of moles for water:

No. of moles of oxygen:

Conversion = 0.822

Selectivity of MAN;

Selectivity of CO;

xi

Selectivity ratio of MAN/CO;

Assuming,

Conversion of n-butane:

Consumption of oxygen:

Production:

Reactor

n-butane = 8081.283 kg/h

Oxygen = 13715.04 kg/h


Maleic Anhydride = 9805.7

kg/h

Carbon Monoxide = 800.526

kg/h

Carbon Dioxide = 1257.806

kg/h

Water = 8750.606 kg/h

8

9

xii

APPENDIX 7: MASS ENERGY BALANCE (ABSORBER)

Example Mass Balance Calculation for Absorber column

According to the US patent 4118403, the dibutyl phthalate (DBP) absorbs 99.4% of the MAN

and 0.1% of the water in the stream.

The gas class components are assumed to exit as gases at the top of the absorber.

Volume feed entering absorber = 100217.558 m3/h

Amount of dibutyl phthalate needed according to US patent 4118403 is 0.2 kg DBP/ m3 feed

entering.

Amount DBP needed = 0.02(100217.558) = 20043.51 ≈ 20000kg/h

At the bottom of absorber:

Amount MAN = 0.96(7518.16) = 7086.58 kg/h

Amount water = 0.001(10021.49) = 100.21

Absorber 10

12

17

11

Isobutane = 1287.80 kg/h

n-butane =1167.74 kg/h

Oxygen =27884.01 kg/h

Maleic anhydride =7158.16 kg/h

Carbon monoxide =1168.42 kg/h

Carbon dioxide = 1835.85 kg/h

Water = 10021.49 kg/h

Nitrogen =130843.36 kg/h

Isobutane = 1287.80 kg/h


Oxygen = 27884.01 kg/h

Maleic anhydride = 71.58 kg/h

Carbon monoxide = 1168.42 kg/h

Carbon dioxide = 1835.85 kg/h

Water = 9921.27 kg/h

Nitrogen = 130843.36 kg/h

Dibutyl phthalate = 20000kg/h


Water = 100.21 kg/h

Dibutyl phthalate = 20000 kg/h

xiii

APPENDIX 8: MASS ENERGY BALANCE (STRIPPER)

Example Mass Balance Calculation for Deisobutanizer distillation column

Calculation of component distribution using Hengstebeck Method

Calculation of saturation pressure of each component using the equation below:

The operating condition of the column is 128.30C and 0.066atm. Since, the pressure of the

column is vacuum, a partial condenser is used to separate the vapor and liquid in the

distillate.

The light key (LK) is water distilled in the top at 99.9% and the heavy key (HK) is dibutyl

phthalate distilled at the bottom at 99.9%

The feed flow rate is 149.69 kgmole/h with the pre-specified feed composition at stream 12.

Example calculation using maleic anhydride:

Partial pressure, Pi = Psat(x) = 9.88(0.48) = 4.715 kPa

Volatility, Ki = Pi/PT = 4.715/6.666 = 0.71

Relative volatility, α = Ki/Khk = 0.71/0.016 = 290.02

The calculation of other component is done below:

Component Mole

flow rate

Mole

fraction

Psat Pi Ki α Log α

Maleic

anhydride

72.27 0.482809 9.765642 4.71494 0.707299 290.0234 2.462

Water 5.562857 0.037163 255.2772 9.486962 1.423161 583.5581 2.766

DBP 71.85366 0.480028 0.033867 0.016257 0.002439 1 0

A graph of log d/b and log α is plotted for the LK and HK as reference for finding the

composition of the other components.

Cmb

dij

i

i

loglog

xiv

Example calculation for water (LK):

d = 0.9999(5.56) = 5.56280

b = 0.001(5.56) = 0.00006

d/b = 5.56280/0.00006 = 99999

log d/b = 5

log α = 2.76608

Component LK HK

F 5.56286 71.85366

D 5.56280 0.00072

B 0.00006 71.85294

d/b 99999 0.00001

lg d/b 5 -5

lg α 2.76608 0

From the graph above, m = -3.6512 and c = -5.

The d/b for other components are calculated.

Example calculation for maleic anhydride:

Mol fraction going to bottom from feed, xbi = 1/(10672.46+1) = 0.0001

y = 3.6152x - 5

-6

-4

-2

0

2

4

6

0.00000 0.50000 1.00000 1.50000 2.00000 2.50000 3.00000 log

d/b

log α

log d/b vs log α

xv

Mol fraction going to distillate from feed, xdi = 1- xbi = 0.9999

Mol flow rate component in bottom, L = xbi(mol flow rate component) = 0.0001(72.27) =

0.013 kgmole/h

Mol flow rate component in distillate, V = xdi(mol flow rate component) = 0.9999(72.27) =

72.2572 kgmole/h

Component log α log di/bi di/bi xbi xdi V L

Maleic

anhydride

2.462 4.028 10672.464 0.000 1.000 72.263 0.007

Water 2.766 5.142 138538.604 0.000 1.000 5.563 0.000

DBP 0.000 -5.000 0.000 1.000 0.000 0.001 71.853

Calculation for partial condenser at the distillate:

Total moles entering flash drum at condenser = 74.69 kgmol/day

Zj=mol fraction in feed, Xj=mol fraction in liquid in outlet, Yj=mol fraction in vapour in

outlet,F

V=vapour to feed ratio, Pj=vapour pressure of component supposed, P=Total pressure

By hit and trail method

At 85 oC and V/F=0.18

Components Zj Pj

KPa P

Pj

11P

P

F

V

ZX

i

j

j j

jX

P

PYi

Maleic anhydride 0.928 1.588 0.224 1.078 0.241

Water 0.072 57.767 8.136 0.032 0.257

Dibutyl phthalate 0.000 0.001 0.000 0.000 0.000

V=0.18*F

=0.18(74.69)

=13.444kgmol/day

L=0.82*F

= 0.82(74.69)

=61.25 kgmol/day

xvi

components Liquid stream

kgmol

L*Xj

vapour stream

kgmol

V*Yj

Maleic anhydride 3.242 66.049

Water 3.462 1.938

Dibutyl phthalate 0.000 0.001

13 Maleic anhydride = 317.89 kg/h

Water = 62.36 kg/h

Deisobutanizer

column


Water = 100.21 kg/h


12

15

14


Water = 34.92 kg/h

Water = 0.000723366 kg/h


xvii

APPENDIX 9: CP VALUE FOR ENERGY BALANCE CALCULATION

Compound Phase Tbp (0C) Tc (K) Pc (bar) Hv

[J/mol] HF [J/mol]

Cp [joule/(mol K)]

A B C D

Propane

gas

-42.1 369.8 42.5 18786 -103920

28.277 1.16E-01 1.96E-04 -2.33E-07

liquid 59.642 3.28E-01 -1.54E-03 3.65E-06

solid -11.23 1.06E+00 -3.60E-03 -

Isobutane

gas

-11.7 408.05 36.48 21399 -135600

6.772 3.41E-01 -1.03E-04 -3.68E-08

liquid 71.791 4.85E-01 -2.05E-03 4.06E-06

solid 110.211 -1.87E+00 1.44E-02 -

n-butane

gas

-0.5 425.2 38 22408 -126230

20.056 2.82E-01 -1.31E-05 -9.46E-08

liquid 62.873 5.89E-01 -2.36E-03 4.23E-06

solid

Isobutene

gas

-6.9 417.85 40.01 22100 -17900

32.918 1.85E-01 7.79E-05 -1.46E-07

liquid 57.611 5.63E-01 -2.30E-03 4.18E-06

solid 34.263 6.85E-02 2.07E-03 -

1-butene

gas

-6.9 417.9 40 22131 -16910

24.915 2.06E-01 5.98E-05 -1.42E-07

liquid 74.597 3.34E-01 -1.39E-03 3.02E-06

solid -11.985 1.15E+00 -3.58E-03

Neopentane

gas

9.5 433.78 31.99 22400 -167000

-17.917 5.72E-01 -4.17E-04 2.12E-07

liquid -186.315 3.24E+00 -1.09E-02 1.34E-05

solid 105.567 -2.66E-01 1.65E-03 -

Iso-pentane

gas

28 460.43 33.81 25220 -153700

-0.881 4.75E-01 -2.48E-04 6.75E-08

liquid 91.474 4.49E-01 -1.69E-03 3.13E-06

solid -10.547 1.25E+00 -3.35E-03 -

n-pentane gas 36 469.6 33.7 25791 -146540 26.671 3.23E-01 4.28E-05 -1.66E-07

xviii

liquid 80.641 6.22E-01 -2.27E-03 3.74E-06

solid -11.568 1.21E+00 -3.24E-03

Oxygen

gas

-183 154.58 50.43 6820 0

29.526 -8.90E-03 3.81E-05 -3.26E-08

liquid 46.432 3.95E-01 -7.05E-03 3.99E-05

solid -16.683 1.59E+00 -2.99E-03 -

Maleic anhydride

gas

200.2 721 72.8 54800 -470410

-72.015 1.04E+00 -1.87E-03 1.65E-06

liquid -12.662 1.06E+00 -2.32E-03 2.05E-06

solid 32.5 2.10E-01 2.73E-04 -

Carbon

monoxide

gas

-191.37 132.92 34.99 6015.8 -110530

29.556 -6.58E-03 2.01E-05 -1.22E-08

liquid 125.595 -1.70E+00 1.07E-02 4.19E-06

solid 21.83 -4.71E-02 6.41E-03 -

Carbon dioxide

gas

-56.57 304.19 73.82 25128 -394000

27.437 4.23E-02 -1.96E-05 4.00E-09

liquid -3981.02 5.25E+01 -2.27E-01 3.29E-04

solid 41.195 3.15E-02 6.41E-05 -

Water

gas

100 647.3 220.5 40683 -242000

33.933 -8.42E-03 2.99E-05 -1.78E-08

liquid 92.053 -4.00E-02 -2.11E-04 5.35E-07

solid 9.695 7.50E-02 -1.56E-05 -

Nitrogen

gas

-156 126.1 33.94 5570 0

29.342 -3.54E-03 1.01E-05 -4.31E-05

liquid 76.452 -3.52E-01 -2.67E-03 5.01E-05

solid 24.334 2.89E-01 1.16E-03

xix

APPENDIX 10: DRAFT OF PLANT LAYOUT

Admin Building

Contro

l

Room

Main Process Area

Waste water

treatment plant

Main

tenan

ce Build

ing

Main Gate

Plan

t Gate

Main Road

Wareh

ouse

Cen

tral Lab

orato

ry

Main

sub

statio

n

Off site Utilities

Storage

tank

farm

Expansion site

Flare system

area

xx

Admin Building

Storage Tank Farm

Maintenance Building

Control

Room

Waste water treatment plant

Offsite Utilities

Main Process Plant

Main Road

Plant Gate Main Gate

Main

sub

station

Central Laboratory

Warehouse

Expansion

site

Documents

CBB 4023 PLANT DESIGN II DESIGN OF MALEIC ANHYDRIDE