UNIVERSITI KEBANGSAAN

MALAYSIA

DEPARTMENT OF CHEMICAL AND PROCESS ENGINEERING

FACULTY OF ENGINEERING & BUILT ENVIRONMENT

2013/2014

PRODUCTION OF TOLUENE

KKKR 3554: PROF. IR. DR. ZAHIRA BINTI YAAKOB

KKKR3634: PROF. MADYA DR. SITI MASRINDA BINTI TASIRIN

KKKR3544: PROF. MADYA IR. DR. MASTURAH BINTI MARKOM

KKKR3544: DR. MUHAMMAD SHUKRI BIN ABD. RAHAMAN

KKKR3524: PROF. MADYA. DR. MEOR ZAINAL BIN MEOR TALIB

KKKR3524: DR. MASLI IRWAN BIN ROSLI

GROUP KK4

NOR ZURAINI BINTI CHE HASHIM A136485

NURUN NADIYATU IZZATI BINTI AHMAD AFIFI A136730

NOOR SHAZLEEN BINTI SHARFADEEN A136900

NASIBAH BINTI MAT HUSSAIN A136386

MUHAMAD FADZLI BIN MAJID A136736

ii

DECLARATION

We hereby declare that the work in this report is our own except for quotations and

summaries which have been duly acknowledged.

6th

DECEMBER 2013

MUHAMAD FADZLI BIN MAJID

(A136736)

NOR ZURAINI BINTI CHE HASHIM

(A136485)

NASIBAH BINTI MAT HUSSAIN

(A136386)

NOOR SHAZLEEN BINTI SHARFADEEN

(A136900)

NURUN NADIYATU IZZATI BINTI AHMAD AFIFI (A136730)

iii

ACKNOWLEDGEMENT

We would like to express our sincere gratitude to all those who lent us a

helping hand in completing and making this Integrated Project a success. Firstly, we

appreciate the advice and time spent by Prof Ir. Dr. Zahira Yaakob, Assoc. Prof. Dr

Siti Masrinda Bt Tasirin, Assoc. Prof. Ir Dr. Masturah Markom, Dr Muhammad

Syukri Bin Abd Rahaman, Assoc. Prof. Dr. Meor Zainal Meor Talib, and Dr. Masli

Irwan Bin Rosli as their assistance and feedback has helped us to compile this project.

Secondly, we truly appreciate the cooperative nature of each person in this

group. We are grateful with the information, suggestions and encouragements shared

between us members. We also appreciate the members precious time and energy

contributed throughout this project.

Furthermore, we would like to thank our course mates for providing

information and data regarding this project, as their help enabled us to complete this

report successfully at the stipulated time.

Hence, we would like to acknowledge everyone once again for their kind help

and contribution towards this project.

Thank you.

iv

ABSTRACT

This report is about the production of Toluene. Toluene is a clear colorless liquid,

sweet, pungent and benzene like odor. Toluene are mainly used in fuel industry,

solvent industry and coolant industry. This plant aims to produce 10% from the Asia

market shortage of toluene which is 84240 tons per year with a mass flowrate of

11700kg/hr. For the production of toluene in our project, there are three raw materials

that involved which are benzene, bromine gas and methane. The chosen reactors for

the reactions process in R-101, R-102 and R-103 is packed-bed reactor (PBR). The

process in reactors R-101 and R-102 are exothermic meanwhile R-103 is endothermic

and the catalyst used is isotope sodium-22. According to the reactor mass balance

calculated manually, the total input mass flow rate for reactor R-103 is similar to

the total output mass flow rate which is also similar to the iCON

result where the

error is only 0.0016%. While at distillation column the condenser heat duty is

10183.33kW. As for separator mass balance, the total input mass flow rate also

similar to the total output mass flow rate 13433.33 kghr-1

and the result by iCON

is

13433.10 kghr-1

, gives the error of 0.0017%. Sieve plate-trays column with 11.35

theoretical stages, and total height of 7.49 m, diameter of 2.5 m is being used.

MATLAB software was used to perform part of the tasks in the project.

v

CONTENT PAGE

Page

DECLARATION ii

ACKNOWLEDGEMENT iii

ABSTRACT iv

CONTENT PAGE v

LIST OF TABLES ix

LIST OF FIGURES x

CHAPTER I INTRODUCTION TO TOLUENE

1.1 INTRODUCTION 1

1.2 PHYSICAL STRUCTURE OF TOLUENE 2

1.3 CHEMICAL PROPERTIES 3

1.4 USAGES OF TOLUENE 4

1.5 RAW MATERIALS

1.5.1 Benzene

1.5.2 Bromine Gas

1.5.3 Methane

5

6

6

CHAPTER II ECONOMIC ASPECT

2.1 INTRODUCTION 8

2.2 DEMAND OF TOLUENE 8

2.3 SUPPLY OF TOLUENE 10

2.4 GLOBAL TOLUENE PRODUCER 10

2.5 FUTURE MARKET POTENTIAL 11

2.6 PROPOSED CAPACITY 11

CHAPTER III ENVIRONMENTAL AND SAFETY ISSUES

PRODUCTION OF TOLUENE

3.1 INTRODUCTION 12

3.2 WASTE GENERATION AND SAFETY

PRECAUTIONS

12

vi

3.2.1 Toluene

3.2.2 Hydrogen Gas

3.2.3 Bromobenzene

3.2.4 Benzene

3.2.5 Bromine Gas

3.2.6 Methane

3.2.7 Hydrogen Bromide

3.2.8 Bromomethane

12

14

15

16

17

18

19

20

3.3 ENVIRONMENTAL ACT 21

CHAPTER IV PROCESS FLOW DIAGRAM

4.1 BLOCK DIAGRAM 23

4.2 PFD DESCRIPTIONS 24

CHAPTER V MASS BALANCE AND ENERGY

BALANCE

5.1 MASS BALANCE 26

5.2 ENERGY BALANCE 32

5.3 iCON COMPARISON FOR MASS AND

ENERGY BALANCE

5.3.1 Mass Balance Comparison

5.3.2 Energy Balance Comparison

37

37

CHAPTER VI REACTOR

6.1 REACTOR DETERMINATION 38

6.2 TYPE OF PROCESS 39

6.3 TYPE OF REACTION 39

6.4 CATALYST 40

6.5 STEPS IN A HETEROGENOUS CATALYTIC

REACTION

40

6.6 GENERAL MASS BALANCE EQUATIONS

AND KINETIC RATE EXPRESSION

41

6.7 KINETIC RATE EXPRESSION 44

vii

CHAPTER VII PARTICLE TECHNOLOGY

7.1 INTRODUCTION 46

7.2 CATALYST SPECIFICATION

7.2.1 Type Of Catalyst

7.2.2 Catalyst Half-Life

7.2.3 Properties Of Catalyst

7.2.4 Catalyst Pore Property

7.2.5 Catalyst Classification

7.2.6 Fluid Flow Through Packed Bed With

Catalyst

7.2.7 Catalyst Contact With Reactants

47

48

49

50

50

52

56

CHAPTER VIII SEPARATION PROCESS

8.1 INTRODUCTION OF SEPARATION

PROCESS

58

8.2 GAS PERMEATION MEMBRANE (G101)

8.2.1 Membrane Selection

8.2.2 Mechanism Of Gas Transport

Mechanism

8.2.3 Type Of Equipment For Gas

Permeation Membrane Process

8.2.4 Type Of Flow In Gas Permeation

Membrane

8.2.5 Membrane Design

8.2.6 Advantages Of Gas Permeation

Membrane

59

60

61

62

63

64

66

8.3 DISTILLATION COLUMN

8.3.1 Mass Balance

8.3.2 Process Design

8.3.3 Heat Duty

8.3.4 Comparison With iCON

8.3.5 Structural Design

66

68

69

70

72

72

viii

8.3.6 Calculation for the Minimum Number

of Stages

8.3.7 Diameter of Distillation Column

8.3.8 Height of Distillation Column

74

75

77

CHAPTER IX CHEMICAL ENGINEERING

COMPUTATION (MATLAB)

9.1 MATLAB SOFTWARE 78

9.2 MASS BALANCE IN R-103

9.2.1 Algorithm And Flowchart

9.2.2 5 Steps Of Problem Solving

78

79

9.3 ENERGY BALANCE IN REACTOR R-103

9.3.1 Algorithm And Flowchart

9.3.2 5 Steps Of Problem Solving

82

83

9.4 SUPPLY AND DEMAND

9.4.1 Algorithm And Flowchart

9.4.2 5 Steps Of Problem Solving

86

87

CONCLUSION 90

REFERENCES 92

APPENDIX 96

ix

LIST OF TABLES

No Table Page

1.1 Material Safety and Data Sheet of Toluene 2

3.1 Hazard ratings production of toluene 13

3.2 Methane Exposure Levels and Effects 18

3.3 Parameters and standard value of waste water discharge limits 22

5.1 Stoichiometric Coefficient 27

5.2 Molar Flow Rate R-103 (kmol/h) 32

5.3 Mass Flow Rate R-103 (kg/h) 32

5.4 Enthalpy of formation of the components 33

5.5 Coefficients of molar heat capacities of the components 33

5.6 Error of mass flowrate (kg/h) at stream 15 and iCON 37

6.1 Stoichiometric table for a flow system 45

7.1 Characteristic of sodium-22 48

7.2 Characteristics of Group C powder 52

8.1 Separation units in process flow diagram 58

8.2 Characteristics of non-porous dense polymeric membrane 60

8.3 Specifications of hollow-fiber membrane 63

8.4 Degree of Freedom Analysis 67

8.5 Molar Flow Rate and Composition 70

8.6 Streams Temperature and Pressure 70

8.7 Molar flow rate, and vapour heat capacity, 71

8.8 Comparison with iCON 72

8.9 K-Values of Components at Distillate and Bottom 74

x

LIST OF FIGURES

No Figure Page

1.1 Molecular diagram of toluene 2

1.2 World consumptions of benzene 6

2.1 Global demand and supply in year 2002 to 2012 9

2.2 Asian demand and supply in year 2002 to 2012 9

2.3 World Consumption of Toluene-2012 10

5.1 Mass Balance for R103 27

5.2 Schematic diagram of Packed bed reactor (R103) 34

6.1 Packed bed reactor 39

6.2 The basis and application of heterogeneous catalysis 41

6.3 Schematic diagram of fixed bed reactor 42

7.1 Hydrodynamic volume of the catalyst 47

7.2 Graph of half-life of isotope sodium-22 49

7.3 Geldarts Classification 51

7.4 Expanded view of a catalyst in a packed bed reactor 53

7.5 Cross sectional area of the packed bed reactor 56

7.6 Pressure drop versus fluid velocity for packed bed and fluidized bed 57

8.1 Membrane Classification 59

8.2 Schematic representation of major gas-transport mechanism 61

8.3 Structure of a hollow-fiber membrane 63

8.4 Ideal flow patterns in a membrane separator for gases 64

8.5 Distillation Column, D102 67

8.6 The Structural of Sieve Tray 73

8.7 Sieve Tray Fractional Distillation Column 73

9.1 Flow chart of the MATLAB code for mass balance 79

9.2 Script MATLAB code for mass balance 81

9.3 Result in Command Window MATLAB 82

9.4 Flow chart of the MATLAB code for energy balance 83

9.5 Script MATLAB code for energy balance 85

9.6 Output MATLAB command window for energy balance 85

xi

9.7 Flow chart of the MATLAB code for supply and demand 87

9.8 Demand and Supply Script MATLAB 88

9.9 Graph of Demand Worldwide 88

9.10 Graph of Supply Worldwide 89

1

CHAPTER I

INTRODUCTION TO TOLUENE

1.1 INTRODUCTION

Toluene is a chemical that was derived from a natural resin namely Tolu balsam, from

Columbia, South America. It was discovered when the resin was burnt and toluene

was obtained as one of the degradation product. The chemical formula of toluene

C7H8 whereby it is a mono-substitued benzene derivative. A methyl atom, CH3

replaces a single hydrogen atom from a group of six hydrogen atoms from a benzene

molecule. The International Union of Pure and Applied Chemistry (IUPAC) name for

toluene is methylbenzene. Among the other names for toluene are phenylmethane,

toluol and anisen. Toluene undergoes electrophilic aromatic substitution when reacted

with aromatic hydrocarbon compounds. It usually undergoes oxidation when reacting

with other reagents such as potassium permanganate, sulphuric acid, halogens and

many more due to the existence of the methyl side chain. There are several methods to

produce toluene such as the Friedel-Crafts reaction, Wurtz-Fittig reaction and

decarboxylation reaction. Toluene is majorly used as a solvent for cleaning and

thinning. It is also used for the production of organic compounds. Below shows the

structure of toluene whereby the methyl group is the substituent for the benzene

group.

2

Figure 1.1 Molecular diagram of toluene

Source : Nguyen K. D., 2011

1.2 PHYSICAL STRUCTURE OF TOLUENE

Toluene is a clear colourless liquid. It exhibits a sweet, pungent and benzene like

odor. It is insoluble in water, however soluble in diethyl ether, acetone, ethanol,

benzene, chloroform, and glacial acetic. Generally, toluene is a stable chemical but

can become unstable if exposed to heat, ignition sources incompatible materials such

as oxidising agents. Below shows a table on the physical properties of toluene.

Table 1.1 Material Safety and Data Sheet of Toluene

Properties Data

Apperance Clear, colourless liquid

Physical state

Chemical Formula

Liquid

C7H8

Odor Sweet, pungent

Molecular Weight 92.14 g/mol

Boiling Point 110.6 oC

Melting Point -95.0 oC

Critical Temperature 318.6 oC

Specific Gravity 0.8636

Vapour Pressure 3.8 kPa @ 25 oC

Flash Point 4 oC

Solubility in water (weight %) 0.074% @ 20 oC

Vapour Density 3.1

Odor Threshold 1.62 ppm

Source : Sciencelab, 2013.

3

1.3 CHEMICAL PROPERTIES

Due to the high electron density in the aromatic ring, toluene acts as a base both in the

formation of charge transfer complexes and in the formation complexes with super

acids. Chemical derivatives of toluene can be obtained through substitution of the

hydrogen atoms of the methyl group, by substitution of the hydrogen atoms of the

ring, and by addition to the double bonds of the ring. Besides that, toluene can also

undergo a disproportionation reaction whereby two molecules react to produce one

molecule of benzene and one molecule of xylene. Below shows some reactions of

toluene (Helmenstein. A.M., 2003).

Substitution of methyl group

Due to the presence of methyl, toluene is approximately 25 times more reactive than

benzene in a substitution reaction. Usually a free-radical and high temperature

reaction gives substitution on the methyl group. Therefore, in the presence of

ultraviolet light or other free-radical initiator at 100oC can yield benzyl chloride,

benzal chloride. Ortho and para isomers are formed in a substitution reaction.

(1.1)

(1.2)

The methyl side chain in toluene may react with other reagent through

oxidation process. If oxygen in the liquid phase and a catalyst is present such as

potassium permanganate with concentrated sulphuric acid, very good yields of

benzoic acid can be obtained.

4

(1.3)

Addition to the ring

Addition reaction can occur to the double bond in the aromatic ring of toluene through

free-radical reaction and catalytic reaction. Chlorination using free-radical initiators at

temperatures

5

Below shown are some of the uses of toluene in various types of industries.

Fuel Industry

Toluene can be utilised as an octane booster in gasoline fuels used in internal

combustion engines. In the 1980, toluene was used as the fuel for all the turbo

Formula 1 teams by 86% in volume. Besides used in land vehicles, toluene can also be

used as a component for jet fuel surrogate blends due to its content of aromatic

compounds.

Solvent Industry

Toluene is also commonly used as a solvent. It has the ability to dissolve paint,

lacquer, silicone sealants, and disinfectant. Toluene is used as a solvent for carbon

nanotubes. Besides that, it is used as a cement for fine polystyrene kits. In addition,

toluene is used as a solvent to break open red blood cell in order to extract

haemoglobin. Toluene can be used as a fullerene indicator. It also is a raw material for

toluene diisocyanate and trinitrotoluene (TNT) which is an explosive substance.

Coolant Industry

Since toluene has good heat transfer capabilities in sodium cold traps, it is used as a

coolant in a nuclear reactor system. Moreover, toluene is used in the process of

removing cocaine from coca leaves in the production in Coca Cola syrup (Hudson. R.,

2012).

1.5 RAW MATERIALS

1.5.1 Benzene

Benzene is an organic chemical compound with the molecular formula C6H6 and it is

classed as a hydrocarbon. Benzene is one of the alkene hydrocarbon. It is a colourless

liquid and one of the aromatic liquid. The molecular weight for benzene is

78.11kg/kmol. Benzene is soluble in alcohol, chloroform, CCl4, diethyl either and

acetone. Its density and boiling point is between 0.8765 g/cm3 and 80.1 C

respectively.

6

Figure 1.2 below is the pie chart world consumptions of benzene in 2008.

Figure 1.2: World consumptions of benzene.

Source: HIS Chemical

1.5.2 Bromine Gas

Bromine is a dense, mobile, slightly transparent reddish-brown liquid. It will

evaporate easily at standard temperature and pressures to become an orange vapor that

is bromine gas. Bromine is the only liquid nonmetallic element. The orange vapor has

a strong unpleasant odor. Bromine is soluble in organic solvents and in water.

Bromine gas can get commercially in various industries. The industrial production of

bromine involves the direct reaction of chlorine with brine rich in bromine ions and

steam into the reaction tower.

1.5.3 Methane

Methane is a tetrahedral molecule with four equivalent C-H bonds. It is a colorless

and odorless gas at room temperature and standard pressure. The boiling point of

methane is -161C at a pressure of one atmosphere. Because of methane is in gas

phase, it wills flammable only over a narrow range concentration of 5-15% in air. But

when methane in liquid phase, it wills not burn unless under high pressure that

7

normally in between 4-5 atmospheres. In industrial routes, methane is produced by

hydrogenating carbon dioxide through the Sabatier process. Other than that, it is also

produced from a side product of the hydrogenation of carbon monoxide in the Fischer-

Tropsch process.

8

CHAPTER II

ECONOMIC ASPECT

2.1 INTRODUCTION

Toluene is an aromatic compound used in the manufacture of benzene, p-xylene for

polyethylene terephthalate (PET) solid-state resins, and toluene diisocyanates (TDI)

for polyurethane applications, and it is widely used as a solvent.

Toluene into the solvents market was basically flat in 2012 with little

economic stimulus in many regions. There is an inherent value in toluene's use in the

gasoline pool both to build octane and to reduce the vapor pressure. This is especially

true when ethanol, which although high in octane has a high vapor pressure, is being

blended into gasoline. Nonetheless, demand for toluene blending into the gasoline

pool is a function of supply, as the reformers need to operate at reasonable rates.

2.2 DEMAND OF TOLUENE

From the source, global demand toluene in 2002 came 18.9 million tons (2.1%

increase on year). In term of average annual growth rates for demand during 2002-

2008 period, demand for toluene is expected to increase 5.6% (Forecast of Global

Supply and Demand Trends for Petrochemical Products, 2004).

9

Estimates suggest that global toluene demand grew by 5.3% in 2012, with

Northeast Asia being the largest market at just over 46% of world demand. The world

toluene petrochemical market slightly exceeded the previously highest level, attained

in 2007 (IHS Chemical Report 2013).

Figure 2.1 Global demand and supply in year 2002 to 2012

Source: Forecast of Global Supply and Demand Trends for Petrochemical Products,

2004

Figure 2.2 Asian demand and supply in year 2002 to 2012

0

5

10

15

20

25

30

2000 2002 2004 2006 2008 2010 2012 2014

Mill

ion

to

ns

Year

Demand

Supply

0

1

2

3

4

5

6

7

8

9

2000 2002 2004 2006 2008 2010 2012 2014

Mill

ion

to

ns

Year

Supply

Demand

10

Source: Forecast of Global Supply and Demand Trends for Petrochemical Products ,

2004

2.3 SUPPLY OF TOLUENE

Throughout the world, consumption in virtually every region was negatively impacted

by the economic recession in 2008 and/or 2009. The developed regions (North

America and Western Europe) declined 8% and 17%, respectively. However, three

regions increased their production of toluene over the same time framethe Middle

East, Northeast Asia and Southeast Asia. Since 2010, most regions have experienced

growth. The fastest growing regions are Africa, the Indian Subcontinent and Northeast

Asia.

However, demand in developing regions such as China, Thailand and the

Middle East saw continued growth during this period. As global economies begin to

slowly recover, toluene markets are anticipated to improve.

The following pie chart shows world consumption of toluene:

Figure 2.3 World Consumption of Toluene-2012

Source: http://www.ihs.com/products/chemical/planning/ceh/toluene.aspx, 2013

2.4 GLOBAL TOLUENE PRODUCER

There are 20 toluene-producing companies in the United States with the capacity to

isolate at least 15 million gallons per year: Amerada Hess, American Petrofina,

11

Amoco Oil, Ashland Oil, BP Chemicals, Champlin, Chevron Chemical, Coastal

Corp., Dow Chemical, Exxon Chemical, Koch Industries, Lyondell Petrochemical,

Marathon Oil, Mobil Oil, Oxy Petrochemicals, Phillips Petroleum, Shell Chemical,

Sun Company, Texaco, and Triangle Refining. These companies represent over 90

percent of US capacity. Annual production capacity for toluene is estimated at 1.5 to

1.7 billion gallons. In 1991, just over 800 million gallons of toluene were isolated in

the US. In the same year, 62 million gallons were imported and 52 million gallons

were exported (Mannsville 1992).

2.5 FUTURE MARKET POTENTIAL

From the Figure 2.2, the ASEAN demand on toluene in year 2002 is 0.4 million tons

and in year 2008 is 0.7 million tons. This show the increase trend in demand on

toluene. Although, the supply on toluene always higher than demand, the toluene still

widely used in industry. Hence, it can be seen that toluene is marketable for current

and future market and has a very good marketing potential as its demand will continue

to increase.

2.6 PROPOSED CAPACITY

From the market research statements above, it has been concluded that the marketing

potential for toluene is good in Asia.

From Figure 2.2, it can be seen that the Asian demand of toluene in 2012 is

7.6869 million tons per year. Thus, the proposed capacity of our plant is 84240 tons

per year with a mass flowrate of 11700 kg/hr. This proposed capacity is calculated

based on Figure 2.2. From Figure 2.2, the Asian demand of toluene in the year 2012

was 7.6869 million tons per year while its production is 6.8445 million tons per year.

The gap between the demand and supply of toluene is 842400 tons per year. Then, our

plant is planned to provide 10% of the shortage of toluene in Asian market, which is

84240 tons per year.

12

CHAPTER III

ENVIRONMENTAL AND SAFETY ISSUES

PRODUCTION OF TOLUENE

3.1 INTRODUCTION

Environmental issues are one of the important considering during the production of

toluene. Any single inappropriate way of handling the chemical will cause huge

impact to the environment especially pollutions. Exposure of chemical to environment

will disturb the balance of the nature. Therefore, it is necessary to pay more attention

to the environmental issues to ensure that the production of toluene does not cause any

pollution.

3.2 WASTE GENERATION AND SAFETY PRECAUTIONS

During a production of a chemical substance, many products will be produced, either

it is a desired product or the undesired products. Any chemical products generated

which are not handle properly, it will become waste and can cause pollution. Different

chemical products are produced and used during the production such as toluene,

hydrogen gas, bromobenzene, benzene, bromine gas, methane, hydrogen bromide and

bromomethane.

3.2.1 Toluene

The appearance of toluene is colourless and the physical state is liquid. It has an

aromatic odor, flammable liquid and vapor. It causes eye, skin, and respiratory tract

irritation. Vapors may cause drowsiness and dizziness. Aspiration hazard if

swallowed, can enter lungs and cause damage. Possible risk of harm to the unborn

13

child. May cause adverse kidney effects and adverse liver effects. Danger of serious

damage to health by prolonged exposure.

Table 3.1: Hazard ratings production of toluene

Hazard Rating NFPA (National Fire Protection Association)

Health 2

Flammability 3

Reactivity 0

Hazard Rating Key: 0=no hazard; 1=slight hazard; 2=moderate hazard; 3=serious

hazard; 4=severe hazard

Source: Toluene MSDS Reliance Industries Ltd, 2011

Precautions: Use personal protective equipment. Remove all sources of ignition.

Take precautionary measures against static discharges. Environmental precautions

should not be released into the environment. Methods for containment and clean up

soak up with inert absorbent material. Keep in suitable and closed containers for

disposal. Remove all sources of ignition. Use spark-proof tools and explosion-proof

equipment.

First Aid Measures and Responses: For inhalation, take precautions to prevent a

fire, for an example remove sources of ignition. Move victim to fresh air. Call a

Poison Centre or doctor if the victim feels unwell. While, for skin contact, avoid direct

contact. Wear chemical protective clothing if necessary. Quickly take off

contaminated clothing, shoes and leather goods such as watchbands and belts. Quickly

and gently blot or brush away excess chemical. Immediately wash gently and

thoroughly with lukewarm, gently flowing water and non-abrasive soap for 15-20

minutes. If irritation or pain persists, see a doctor. Thoroughly clean clothing, shoes

and leather goods before reuse or dispose of safely. Avoid direct eye contact. Wear

chemical protective gloves if necessary. Quickly and gently blot or brush chemical off

the face. Immediately flush the contaminated eye(s) with lukewarm, gently flowing

water for 5 minutes, while holding the eyelid(s) open. If irritation or pain persists, see

a doctor.

14

Handling and Storage: In the event of a spill or leak, exit the area immediately.

Eliminate heat and ignition sources such as sparks, open flames, hot surfaces and

static discharge. Post "No Smoking" signs. Avoid generating vapours or mists.

Electrically bond and ground equipment. Ground clips must contact bare metal. Avoid

repeated or prolonged skin contact with product or with contaminated equipment or

surfaces. Store in an area that is cool, well-ventilated, out of direct sunlight and away

from heat and ignition sources, clear of combustible and flammable materials such as

old rags and cardboard, separate from incompatible materials. Keep amount in storage

to a minimum. Electrically bond and ground containers. Ground clips must contact

bare metal. Avoid bulk storage indoors.

3.2.2 Hydrogen Gas

Hydrogen is the most plentiful gas in the universe. It has high energy content by

weight, but a low energy content by volume. Hydrogen, H2 is a colorless, odorless,

tasteless, and highly flammable gaseous substance which is flammability range from

4% to 74% in air will ignite, while mixtures of between 18% and 59% in air may

explode. It creates a pale blue flame when ignited, but is virtually invisible in a well

lighted area or bright day light.

The substance can be absorbed into the body by inhalation. High

concentrations of this gas can cause an oxygen-deficient environment. Individuals

breathing such an atmosphere may experience symptoms which include headaches,

ringing in ears, dizziness, drowsiness, unconsciousness, nausea, vomiting and

depression of all the senses. The skin of a victim may have a blue color. Under some

circumstances, death may occur. Hydrogen is not expected to cause mutagenicity,

embryotoxicity, teratogenicity or reproductive toxicity. Pre-existing respiratory

conditions may be aggravated by overexposure to hydrogen. Inhalation risk, on loss of

containment, a harmful concentration of this gas in the air will be reached very

quickly.

Precautions: Follow all proper safety procedures for returning the system or systems

back to the owner after repairs or maintenance. After repairs or maintenance, gaseous

15

and liquid hydrogen systems must be purged of all air and oxygen with an inert gas

and tested with the proper metering analyzer to ensure no oxygen remains in the

system prior to re-introducing hydrogen to the lines, vessels and equipment.

First Aid Measures and Responses: In fire, shut off supply, if not possible and no

risk to surroundings, let the fire burn itself out, in other cases extinguish with water

spray, powder, carbon dioxide. Explosion, in case of fire, keep cylinder cool by

spraying with water. Combat fire from a sheltered position. Inhalation, fresh air and

rest. Artificial respiration may be needed and refer to medical attention. For skin may

refer to medical attention.

Handling and Storage: Know and understand the properties, proper uses and safety

precautions of hydrogen before using the gas and associated equipment. Consult the

Air Products Material Safety Data Sheet (MSDS) for safety information. Never crack

open a hydrogen cylinder to clear the valve of dust as the escaping hydrogen may

ignite. Never drop, drag, roll or slide cylinders. Use a specifically designed hand-truck

for cylinder movement. If a cylinder or valve is defective or leaking, remove the

cylinder to a remote outdoor location away from possible sources of ignition and post

the as to the hazard involved. Notify the gas supplier. For storage, cylinders should be

stored upright in a well ventilated, dry, cool, secure area that is protected from the

weather and preferable fire-resistant. No part of a cylinder should ever be allowed to

exceed 125F (52C) and areas should be free of combustible materials. Never

deliberately over heat a cylinder to increase the pressure or discharge rate. Cylinders

should be stored away from heavily traveled areas and emergency exits. Avoid areas

where salt and other corrosive materials are present.

3.2.3 Bromobenzene

Bromobenzene also known as phenyl bromide is a clear, colorless liquid with a

pleasant odor. It is used as a solvent and motor oil additive and in making other

chemicals. It is flammable and irritating to skin. Toxic to aquatic organisms, may

cause long-term adverse effects in the aquatic environment.

16

Precautions: For ventilation, supply mechanical or local exhaust. Wear chemical-

resistant clothing. Wear safety glasses with splash shields or safety goggles or shield.

To prevent skin contact, wear rubber or neoprene gloves and use rubber safety boots.

First Aid Measures and Responses: Immediately flush eyes with plenty of water for

at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid.

For skin, flush skin with plenty of soap and water for at least 15 minutes while

removing contaminated clothing and shoes. Get medical aid. If victim is conscious

and alert, give 2-4 cup fulls of milk or water. Never give anything by mouth to an

unconscious person. Get medical aid immediately. Inhalation, remove from exposure

to fresh air immediately. If not breathing, give artificial respiration. If breathing is

difficult, give oxygen. Get medical aid.

Handling and Storage: Protect against physical damage. Store in a cool, dry well-

ventilated location, away from any area where the fire hazard may be acute. Outside

or detached storage is preferred. Separate from incompatibles. Containers should be

bonded and grounded for transfers to avoid static sparks. Storage and use areas should

be No Smoking areas. Use non-sparking type tools and equipment, including

explosion proof ventilation

3.2.4 Benzene

Benzene is a clear, sweet-smelling, highly flammable liquid. It is also known as

benzol, benzole, coal naphtha, cyclohexatriene, phene, phenyl hydride, and

pyrobenzol. Benzene is harmful if it is inhaled, absorbed through the skin or

swallowed. Although benzene is carcinogenic, it can be used with little risk to health

if used properly

Precautions: Benzene is explosive in nature and it can affect skin. Safety glasses or

goggles are recommended where there is a possibility of splashing or spraying. For

skin protection, gloves constructed of nitrile or neoprene are recommended. Chemical

protective clothing such as of E.I.DuPont Tyvek-Saranex 23, Tychem, Barricade

or equivalent recommended based on degree of exposure.

17

First Aid Measures and Responses: Splashed in eyes, wash out immediately with

large amounts of water and if eyes remain irritated or vision becomes blurry, see a

doctor as soon as possible. Spilled on body, take off the contaminated clothing,

thoroughly wash the contacted skin with soap and water immediately. Inhaled large

amounts, quickly get the exposed person to fresh air. Apply artificial respiration if

the person has stopped breathing and call for medical assistance

Handling and Storage: Store in tightly closed containers in a cool, well-ventilated

area away from sparks or flames. Transfer of benzene from one container to another

must be done in well ventilated area. Transfer only with grounded, non-sparking

equipment. Benzene vapors are heavier than air so vapors may travel along the ground

and ignite somewhere away from where it is being handled. Fire extinguishers must be

readily available.

3.2.5 Bromine Gas

Bromine is a volatile liquid that possesses a very strong, suffocating odor. It is

reddish-brown in appearance and highly corrosive, capable of dissolving both metals

and nonmetals. Because it is an oxidizer, it can also react with inorganic material such

as sawdust, creating extreme heat and possibly fire. When exposed to sunlight and

humid air or hot water, bromine can react to form hydrobromic acid, which is not as

toxic as bromine but retains its irritant properties.

Precautions: Gloves and lab coats are required when handling hazardous chemicals.

Closed shoes are required in the lab for safety protections while handling hazardous

chemicals.

First Aid Measures and Responses: For eyes get medical aid immediately. Do not

allow victim to rub or keep eyes closed. Extensive irrigation with water is required at

least 30 minutes. While for skin, immediately flush skin with plenty of soap and water

for at least 15 minutes while removing contaminated clothing and shoes. Wash

clothing before reuse. Destroy contaminated shoes. Inhalation, remove from exposure

to fresh air immediately. If not breathing, give artificial respiration. If breathing is

difficult, give oxygen.

18

Handling and Storage: Avoid contact with skin and eyes and avoid formation of

vapors, dusts, mists and aerosols. Use appropriate exhaust ventilation and keep

flammable, pyrophoric, potentially explosive and water reactive chemicals away from

sources of ignition. The conditions for safe storage is keep in proper storage away

from heat, sparks and flame. Segregate incompatible chemicals and keep away from

reducing agents.

3.2.6 Methane

Methane is an odourless gas and is lighter than air. Because methane is lighter than

air, it tends to rise and accumulate near the higher, stagnant parts of enclosed

buildings and tightly closed manure storage pits. It is most likely to accumulate during

hot, humid weather. National Institute for Occupational Safety and Health's (NIOSH)

maximum recommended safe methane concentration for workers during an 8-hour

period is 1,000 ppm (0.1 percent). Methane is considered an asphyxiation at extremely

high concentrations and can displace oxygen in the blood according Table 3.2 below.

Table 3.2 Methane Exposure Levels and Effects

Exposure Level (ppm) Effect or Symptom

1 000 NIOSH 8-hours Threshold Limit Value

50 000 to 150 000 Potentially Explosive

500 000 Asphyxiation

Source : Atta Atia, 2004

Precautions: Safety eyewear complying with an approved standard should be used

when a risk assessment indicates this is necessary to avoid exposure to liquid splashes,

mists or dusts. Personal protective equipment for the body should be selected based on

the task being performed and the risks involved and should be approved by a specialist

before handling this product Insulated gloves suitable for low temperatures.

First Aid Measures and Responses: Eye contact safety. Immediately flush eyes with

plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids

and get medical attention immediately. In case of contact, immediately flush skin with

plenty of water for at least 15 minutes while removing contaminated clothing and

shoes. To avoid the risk of static discharges and gas ignition, soak contaminated

19

clothing thoroughly with water before removing it. Wash clothing before reuse. For

inhalation problem, move exposed person to fresh air and provide artificial respiration

or oxygen by trained personnel.

Handling and Storage: Use only with adequate ventilation. Use explosion-proof

electrical ventilating, lighting and material handling equipment. Do not puncture or

incinerate container. Keep container closed. Keep away from heat, sparks and flame.

Keep container in a cool, well-ventilated area. Keep container tightly closed and

sealed until ready for use. Avoid all possible sources of ignition either spark or flame.

Segregate from oxidizing materials. Cylinders should be stored upright, with valve

protection cap in place, and firmly secured to prevent falling or being knocked over.

3.2.7 Hydrogen Bromide

Hydrogen Bromide is a colorless gas with a sharp, suffocating pungent odor. Shipped

as liquefied compressed gas and often used in an aqueous solution. Excessive

inhalation may cause burning sensations, coughing, shortness of breath, headache,

nausea and vomiting. May produce bronchitis, chemical pneumonitis and pulmonary

edema. Contact with liquid HBr may cause skin burns. Eye contact may result in

destruction of eye tissue. Excessive exposure can be fatal.

Precautions: Engineering controls, provide adequate general and local exhaust

ventilation to maintain concentration below exposure limits. For eye or face

protection, wear safety glasses and for skin protection,impervious gloves, coveralls,

boots, or other resistant protective clothing. Safety shoes when handling cylinders.

First Aid Measures and Responses: Inhalation, immediately remove victim to fresh

air. If breathing has stopped, give artificial respiration. If breathing is difficult, give

oxygen. For eye contact, immediately flush eyes, including under the eyelids, gently

but thoroughly with plenty of running water for at least 15 minutes. Meanwhile, for

skin contact, immediately flush with copious amounts of water for at least 15 minutes

while removing contaminated clothing.

Handling and Storage: Secure cylinder when using to protect from falling. Use

suitable hand truck to move cylinders. Precautions to be taken in storage is keep in a

20

cool, well ventilated place. Keep valve protection cap on cylinders when not in use.

Store away from heat, flame, and sparks.

3.2.8 Bromomethane

Bromomethane, commonly known as methyl bromide, is an organobromine

compound with formula CH3Br. This odorless, colorless nonflammable gas is

produced both industrially and particularly biologically. It has a tetrahedral shape and

it is a recognized ozone-depleting chemical. It was used extensively as a pesticide

until being phased out by most countries in the early 2000s.

Precautions: Provide local exhaust or process enclosure ventilation system. Ensure

compliance with applicable exposure limits. Wear splash resistant safety goggles with

a face shield. Provide an emergency eye wash fountain and quick drench shower in

the immediate work area. Protective clothing is not required. Wear appropriate

chemical resistant gloves.

First Aid Measures and Responses: Inhalation aid if adverse effects occur, remove

to uncontaminated area. Give artificial respiration if not breathing, get immediate

medical attention. Skin contact, wash skin with soap and water for at least 15 minutes

while removing contaminated clothing and shoes. For eye contact, flush eyes with

plenty of water for at least 15 minutes. Then get immediate medical attention. If

swallowed, drink plenty of water, do not induce vomiting. get immediate medical

attention.

Handling and Storage: Avoid bodily contact. Use an appropriate monitoring

instrument for bromomethane in any area where it is being stored or handled. Store

cylinders and cans upright, in a secure manner, either outdoors under ambient

conditions, or indoors in a well ventilated area, away from seeds, foods or feed-stuffs

and human and animal habitation.

21

3.3 ENVIRONMENTAL ACT

The purpose of environmental act is to ensure that the plant will not discharge any

particular material that is hazardous and toxic to the environment. Next, it is to make

sure that the plant is safe to human kind and the ecosystem from any critical

environment disturbance. The environmental act that is related to the production of

toluene plant is the Environmental Quality Act 1974 quote by Law of Malaysia, Act

127, and Environmental Quality Act 1974.

These are the list of Environmental Quality Act regulation that is followed by the

toluene plant:

Section 21:

Power to specify conditions of emission and discharge.

Section 22:

Restriction on pollution to the atmosphere.

Section 25:

Restriction on pollution of inland waters.

Section 29 and section 29 (a):

Prohibition discharge waste into Malaysia Water.

Section 31 (a):

Prohibition order to the owner or occupier of any industrial plant or process to

prevent its continued operation and release of environmentally hazardous

substances, pollutants or wastes either absolutely or conditionally, or for such

period as he may direct, or until requirements to make remedy as directed by

him have been complied with.

Table 3.3 below shown the waste water discharge limit, according to the Malaysias

Environmental Law, Environmental Quality Act, 1974, the Malaysia Environmental

Quality (Sewage and Industrial Effluent) regulation, 1979, 1999, 2000:

22

Table 3.3: Parameters and standard value of waste water discharge limits

Parameters Standards

Temperature 40oC

pH Value 6.0-9.0

BOD at 20oC 50 mg/l

COD 100 mg/l

Oil and Grease 10 mg/l

Suspended solids 100 mg/l

Source : Malaysia Department of Environment, 2008

23

CHAPTER IV

PROCESS FLOW DIAGRAM

4.1 BLOCK DIAGRAM

Where:

CH4 = Methane G101 = Gas Permeation Membrane 1

Br2 = Bromine gas R103 = Reactor 3

C6H6 = Benzene P101 = Phase Separator 1

H2 = Hydrogen gas D102 = Distillation Column 2

C7H8 = Toluene

C6H5Br = Bromobenzene

R101 = Reactor 1

D101 = Distillation Column 1

R102 = Reactor 2

24

4.2 PFD DESCRIPTIONS

From the process flow diagram for production of toluene, the process is being start by

feed benzene,C6H6 to the H101 at stream 3. The temperature of the benzene will be

increase from 25C to 98C until it is suitable to be react and mix in the R101.

Benzene is then feed into the R101 at stream 4 and will be react with bromine gas that

being feed at stream 2. This reaction will produce bromobenzene,C6H5Br and

hydrogen bromide,HBr. The product, byproduct byproduct and unreacted reactant will

be cooled from 310C to 45C and then it being purge into the D101 through stream

6. Hydrogen bromide will distilled into the upper stream 7 and feed into R102 to react

with methane that feed at stream 1. This reaction will then produce

bromomethane,CH3Br and hydrogen gas,H2. From R102, the product will feed into

G101 through stream 11. Hydrogen gas will be purge into the storage tank through

stream 13 while hydrogen bromide and another unreacted reactant will continue being

purge into R103 through stream 14 for the next reactor. At C101, bromobenzene,

byproduct and unreacted reactant will be feed into R103 through stream 12. In R103,

bromobenzene and bromobenzene will be react to form toluene and bromine gas with

the present of Sodium-22 metal as the catalyst. All the product and byproduct will be

feed into P101 and through H103 the product will be heat up from 250C to 260C.

The gas product will be purge from P101 through stream 16 into the waste storage

tank while the liquid product, bromobenzene and toluene,C7H8 will be purge into

another distillation column,D102 through stream 18. Based on the molecular weight,

toluene is more lighter than bromobenzene, so toluene will be purge into upper stream

through stream 19 to the storage tank and bromobenzene will be purge down stream

through stream 22 into the storage tank.

25

26

CHAPTER V

MASS BALANCE AND ENERGY BALANCE

5.1 MASS BALANCE

Based on the demand and supply for toluene in Asia in year 2012, the supply of

toluene does not meet the demand thus causing a shortage of toluene. Below shown is

the data for the toluene in the Asia region.

Asia demand for toluene in 2012 = 7.6869 million tonnes

Asia supply for toluene in 2012 = 6.8445 million tonnes

Shortage of toluene in 2012 = 0.8424 million tonnes

This project proposes to produce a plant that produces 10% of the Asia region

shortage.

10% of 0.8424 million tonnes = 84 240 000 kg.

The process design is expected to work for 300 days per year.

300 days x 24 hours/day = 7200 hours/year

Mass flowrate =

= 11 700 kg/hr

Molar flowrate =

= 126.98 kmol/hr

27

There are three reactors in our design process. The main reaction occurs in Reactor 3

whereby the reaction equation is shown below.

C6H5Br (g) + CH3Br(g) + Na(s) C7H8(l) + Br2(g) (5.1)

R103

X = 0.92

Figure 5.1 Mass Balance for R103

Note : C6H5Br = Bromobenzene

HBr = Hydrogen Bromide

C6H8 = Benzene

Br2 = Bromine gas

CH3Br = Bromomethane

C7H8 = Toluene

Table 5.1: Stoichiometric Coefficient

Ethanolamine Ammonia Ethylenediamine Water

-1 -1 1 1

Estimated conversion, X = 0.92

F8, C6H5Br

F8,HBr

F8,C6H6

F8,Br

F12, C6H5Br

F12, HBr

F12, C6H6

F12,Br

F12, CH3Br

F12, C7H8

F10,CH3Br

28

Estimated equilibrium constant, Ke = 5

Mole balance for components:

(a) Toluene,

Given No= 126.98 kmole/h

No=Ni+r

126.98 = 0+(1)r

r = 126.98 kmole/h

(b) Bromine gas,

No=Ni+r

No= 0+(1)(126.98)

= 126.98 kmole/h

(c) Bromobenzene,

No=Ni+r

Conversion, X=

XNi= Ni-No

XNi= -r

(0.92)Ni= -(-1)(126.98)

Ni= 138.02 kmole/h

No=Ni+r

= 138.02 + (-1)(126.98)

= 11.04 kmole/h

29

From equilibrium constant:

Ke = (Nik + kr)k

=

5.0 =

5.0 =

NiCH3Br = 419.08 kmole/h

(d) Bromomethane,

No=Ni+r

No= 419.08 + (-1) (126.98)

= 292.10 kmole/h

To determine the limiting reactant,

For bromobenzene (C6H5Br) =

=

= 138.02 kmole/h

For bromomethane (CH3Br) =

=

= 419.08 kmole/h

Hence, the limiting reactant is bromobenzene (C6H5Br) .

30

Total input molar flow rate, NiT = NiC6H5Br + NiCH3Br + NiC7H8 + NiBr2

= (138.02 + 419.08 + 0 + 0) kmole/h

= 557.10 kmole/h

Total output molar flow rate, NoT = NoC6H5Br + NoCH3Br + NoC7H8 + NoBr2

= (11.04 + 292.10 + 126.98 + 126.98) kmole/h

= 557.10 kmole/h

Composition of input components:

Bromobenzene, xiC6H5Br =

=

= 0.2477

Bromomethane, xiCH3Br =

=

= 0.7523

Composition of output components:

Bromobenzene, xoC6H5Br =

=

= 0.0198

Bromomethane, xoCH3Br =

=

= 0.5243

31

Toluene, xoC7H8 =

=

= 0.2279

Bromine gas, xoBr2 =

=

= 0.2279

Mass flow rate for input components :

Bromobenzene (C6H5Br), FiC6H5Br = NiC6H5Br x MC6H5Br

= 138.02 x 157.01 = 21670.52 kg/h

Bromomethane (CH3Br), FiCH3Br = NiCH3Br MCH3Br

= 419.08 x 94.94 = 39787.46 kg/h

Total input mass flow rate = FiC6H5Br + FiCH3Br = 61457.98 kg/h

Mass flow rate for output components :

Bromobenzene (C6H5Br), FoC6H5Br = NoC6H5Br x MC6H5Br

= 11.04 x 157.01 = 1733.39 kg/h

Bromomethane (CH3Br), FoCH3Br = NoCH3Br MCH3Br

= 292.10 x 94.94 = 27731.97 kg/h

Toluene (C7H8), FoC7H8 = NoC7H8 MC7H8

= 126.98 x 92.14 = 11699.94 kg/h

Bromine gas (Br2), FoBr2 = NoBr2 MBr2

32

= 126.98 x 159.80

= 20291.40 kg/h

Total output mass flow rate = FoC6H5Br + FoCH3Br + FoC7H8 + FoBr2 = 61456.70 kg/h

Table 5.2: Molar Flow Rate R-103 (kmol/h)

Components Nin(kmol/h) Nout(kmol/h)

Bromobenzene,C6H5Br 138.02 11.04

Bromomethane,CH3Br 419.08 292.10

Toluene,C7H8 0 126.98

Bromine gas,Br2 0 126.98

Total 557.10 557.10

Table 5.3: Mass Flow Rate R-103 (kg/h)

Components Nin(kmol/h) Nout(kmol/h)

Bromobenzene,C6H5Br 21670.52 1733.39

Bromomethane,CH3Br 39787.46 27731.97

Toluene,C7H8 0 11699.94

Bromine gas,Br2 0 20291.40

Total 61457.98 61457.70

Fin = Fout 61457.00 kg/h

Hence, reaction inside reactor R-103 is balanced.

5.2 ENERGY BALANCE

To calculate the energy balance for reactor unit operation in the plant design, the data

for the enthalpy of formation of the components is needed as shown in Table 5.4

below.

33

Table 5.4: Enthalpy of formation of the components

Components Enthalpy of formation,Hof (kJ/mol)

Bromobenzene, C6H5Br

Bromomethane, CH3Br

Toluene, C7H8

Bromine, Br2

58.60

-33.50

12.00

30.91

Source: Perry Handsbook, 2008

Moreover, to find the molar enthalpy change of a component that flow in and out at

every unit operation, have to get the information for the coefficients of molar heat

capacities of the components where T1 in standard condition, 25oC or 298 K .

Assumptions:

1. There are no kinetic energy, potential energy and work done by the system.

2. The references temperature is 25oC

Table 5.5 Coefficients of molar heat capacities of the components

Cp = a + bT + cT2 + dT

3 , unit in kJ/kmol.K

Components a b c d

Bromobenzene,

C6H5Br

0.721x10-5

2.064x10-5

1.650x10-3

1.687x10-5

Bromomethane,

CH3Br

0.3377x10-5

0.715x10-5

1.578x10-3

0.418x10-5

Toluene, C7H8 0.5814x10-5

2.863x10-5

1.441x10-3

1.898x10-5

Bromine, Br 0.301x10-5

0.081x10-5

0.751x10-3

0.108x10-5

Source: Property Tables Booklet, 2011

34

Energy Balance Calculation for Packed Bed Reactor (R-103)

Figure 5.2 Schematic diagram of Packed bed reactor (R103)

Chemical reaction in the reactor is as below,

C6H5Br (g) + CH3Br(g) + Na(s) C7H8(l) + Br2(g) (5.2)

Rate of reaction = r

No,C7H8 = Ni,C7H8 + ( x r)

126.98 = 0 + (1)r

r = 126.98 kmol/hr

reaction = o-i

= (formation ,C7H8 +formation,Br2) (formation,C6H5Br + formation,CH3Br)

= [12.0 + 30.91] [58.6+(-33.5)]

= 17.81 kJ/mol

Hreaction = r x reaction = 126.98 kmol/hr x 17.81 kJ/mol

T= 423K

Ni,CH3Br = 419.08 kmol/hr

T= 303K

Ni,C6H5Br = 138.02 kmol/hr

T= 523K

No,C7H8 = 126.98 kmol/hr

No,C6H5Br =11.04 kmol/hr

No,Br2=126.98 kmol/hr

No,CH3Br=292.10 kmol/hr

35

= 22615.51 kJ/hr

Inlet components :

Stream 10,

Bromomethane, CH3Br

CH3Br=

0.3377x10

-5+0.715x10

-5T+1.578x10

-3T

2+0.418x10

-5T

3 dT

= 51076.92 J/kmol

Stream 8,

Bromobenzene, C6H5Br

C6H5Br=

0.721x10

-5+2.064x10

-5T+1.650x10

-3T

2+1.687x10

-5T

3 dT

= 3034.22 J/kmol

Thus, Nii = CH3Br2x Ni,CH3Br + C6H5Brx Ni,C6H5Br

=(51076.92x419.08) + (3034.22x138.02)

=21.824x106 kJ/hr

Outlet components: Stream 12

Toluene, C7H8

C7H8=

0.5814x10

-5+2.863x10

-5T+1.441x10

-3T

2+1.898x10

-5T

3 dT

=373582.33 J/kmol

Bromobenzene, C6H5Br

C6H5Br=

0.721x10

-5+2.064x10

-5T+1.650x10

-3T

2+1.687x10

-5T

3 dT

36

=346428.65 J/kmol

Bromine, Br2

Br2 =

0.301x10

-5+0.081x10

-5T+0.751x10

-3T

2+0.108x10

-5T

3 dT

=47240.67 J/kmol

Bromomethane, CH3Br

CH3Br=

0.3377x10

-5+0.715x10

-5T+1.578x10

-3T

2+0.418x10

-5T

3 dT

= 131188.33 J/kmol

Thus, Noo = C7H8x No,C7H8 + C6H5Brx No,C6H5Br + Br2x No,Br2 + CH3Br2x

No,CH3Br

=(373582.33x126.98)+( 346428.65x11.04)+(47240.67x126.98)+(131188.33x292.10)

= 95.581 x 106 kJ/hr

So, the heat of energy, Q

Q = Noo Nii + Hreaction

= (95.581 x 106) (21.824x106) + (22615.51) = 73.780 x 106 kJ/hr

The reaction in packed bed reactor is endothermic process. The heat energy absorbed

by the reactor is 73.780 x 106

kJ/hr.

37

5.3 iCON COMPARISON FOR MASS AND ENERGY BALANCE

5.3.1 Mass Balance Comparison

Table 5.6: Error of mass flowrate (kg/h) at stream 15 and iCON

Components Stream 15 iCON Error(%)

Bromobenzene,C6H5Br 1733.39 1733.64 0.0144

Bromomethane,CH3Br 27731.97 27732.16 0.0007

Toluene,C7H8 11699.94 11699.75 -0.0016

Bromine gas,Br2 20291.40 20292.44 0.0052

Total 61456.70 60897.99 -0.9175

5.3.2 Energy Balance Comparison

Qcalc = 73.780 x 106

kJ/hr.

QiCON = 4058312.4894 W

= 14.6099x106 kJ/hr.

Error =

x 100%

= 80.20%

38

CHAPTER VI

REACTOR

6.1 REACTOR DETERMINATION

A reactor is designed to contain chemical reactions. It is the place where the

conversion of raw materials occur into desired products thus it known to be the heart

of a chemical process. The design of a reactor in a commercial scale would be affected

by several aspects of chemical engineering. Since it is an important step in the overall

design process, one should ensure that the reaction proceeds with the highest yield of

product in the most cost efficient way and also the highest efficiency towards the

desired output.

There are three reactors in this process, however the most important reactor

namely R103, is used to synthesis the main product that is toluene. A packed bed

reactor is chosen as the suitable reactor to ensure an optimum reaction process in the

reactor. A packed bed reactor is a hollow tube that is filled with packing material such

as raschig rings. It is made up of ceramic or metal and it provides large surface area

within the volume of the column for interaction between the reactant.

39

Figure 6.1 Packed bed reactor

Source : Hindawi Publication Corp. 2013

6.2 TYPE OF PROCESS

The chemical reaction in the packed bed reactor undergoes a continuous process. This

process occurs when the reactants are fed into the reactor and the products are

withdrawn while the reaction is still in progress. A continuous packed bed reactor is

chosen as it has much more advantages compared to a batch packed bed reactor.

Firstly, it has an easy and automatic control operation. Secondly, a continuous packed

bed reactor can reduce labour costs. Thirdly, the operating conditions can be stabilized

certainly with the use of a packed bed reactor. Finally, it will be easier to control the

quality of the products formed from a packed bed reactor. Hence continuous reactors

are preferred for large scale production (Rensselaer, 2004).

6.3 TYPE OF REACTION

For the synthesis of toluene, gaseous methyl bromide and liquid bromobenzene are

fed into the continuous packed bed reactor. Since there is a mixture of gas and liquid

in the feed stream, a heterogeneous reaction occurs in the reactor. In a heterogeneous

reaction, two or more phases exists and the usual problem that may arise in the reactor

design is to promote mass transfer between the phases (Nanda. S. et al. 2008).

Packing material

40

6.4 CATALYST

A catalyst is a substance that alters a rate of reaction without itself undergoing any

permanent chemical change. It also provides an alternative pathway or lowers the

activation energy for e specific reaction. For the production of toluene, solid isotopes

Sodium-22 catalyst is needed to speed up the reaction. The usage of the catalyst can

further be optimized with the presence of sodium metal in the presence of dry ether.

6.5 STEPS IN A HETEROGENOUS CATALYTIC REACTION

There are several steps in a heterogeneous catalytic reaction. Firstly, there is mass

transfer via diffusion of the reactants namely bromobenzene and bromomethane from

the bulk fluid to the external surface of the catalyst pellet, isotope Sodium-22 metal.

Then the diffusion of the reactants from the pore mouth through the catalyst pores to

the immediate vicinity of the internal catalytic surface occurs. The reactors are

adsorbed onto the catalyst surface and a reaction takes place on the surface of the

catalyt. After the reaction has taken place, desorption of the product namely toluene

and bromine from the catalyst surface occurs. Then, the products formed are diffused

from the interior of the catalyst pellet to the pore mouth at the external surface. Lastly,

mass transfer of the products from the external pellet surface to the bulk fluid takes

place.

41

Figure 6.2 The basis and application of heterogeneous catalysis

Source : Bowker. M. 1998.

6. 6 GENERAL MASS BALANCE EQUATIONS AND KINETIC RATE

EXPRESSION

The production of toluene shown by the following reaction:

Na(s)

C6H5Br (l) + CH3Br (g) C7H8 (l) + Br2 (g) (6.0)

(Bromobenzene) (Methyl bromide) (Toluene) (Bromine gas)

Adsorption process. Catalytic reaction for the catatlyst:

Let A = C6H5Br

B = CH3Br

C = C7H8

42

D = Br2

N = Na

Assume this reaction is reversible process:

Adsorption on Surface: A + N A . S

B + N B . S

Surface Reaction: A . S + B . S C . S + D . S

Dual Site: A . S + B . S C . S + D . S

Eley-Rideal: A . S + B (g) C . S + D(g)

Desorption from surface: C . S C + S

The general mole equation is

(6.1)

Figure 6.3 Schematic diagram of fixed bed reactor.

43

In - Out + Generation = Accumulation

FA0 - FA1 + rA W = dNA / dt (6.2)

Assume that FBR is operated at steady state,

FA0 - FA1+ rA W = 0 (6.3)

Dividing by W and rearranging,

(FA0 - FA1) / W = rA (6.4)

Taking the limit as W approaches zero, we obtain the differential from of steady

state mole balance on a Fixed Bed Reactor (FBR):

dFA / dW = rA (6.5)

For a flow system,

FA = FA0 - FA0X (6.6)

Differentiating,

dFA = -FA0 dX (6.7)

Subsitute (6.7) into (6.5) gives the differential form of mole balance on a Fixed Bed

Reactor (FBR) based on the conversion:

FA0 (dX/dW) = -rA (6.8)

Use the above differential form of the mole balance on FBR when there is pressure

drop or catalyst decay.

44

6. 7 KINETIC RATE EXPRESSION

Main reaction:

Na(s)

C6H5Br (l) + CH3Br (g) C7H8 (l) + Br2 (g) (6.9)

(Bromobenzene) (Methyl bromide) (Toluene) (Bromine gas)

Let A = C6H5Br

B = CH3Br

C = C7H8

D = Br2

Reaction Stoichiometry

-rA= -rB = rC = rD (6.10)

Rate Law:

- = kCACB (6.11)

Because we are taking bromobenzene as our basis, we divide through by the

stoichiometric coefficient of toluene to put the reaction expression in the for

A + B C + D (6.12)

Where,

B = FB0 / FA0 = CB0v0 / CA0v0 = CB0 / CA0 = yB0 / yA0 (6.13)

C and D are defined similarly.

For gases, volume change with reaction is :

(6.14)

as P0 = P and T0 = T

45

So,

(6.15)

We may then perform the calculation shown below:

Table 6.1: Stoichiometric table for a flow system

Species Symbol Feed rate to

reactor

(mol/time)

Change

within

reactor

(mol/time)

Effluent rate

from reactor

(mol.time)

Concentration

(mol/liter)

C6H5Br

A - X =

CH3Br

B B - = B

C7H8 C C = C

Br2 D D = D

Thus, subtitute the value of concentration CA and CB into the rate law equation,

- = k

(6.16)

46

CHAPTER VII

PARTICLE TECHNOLOGY

7.1 INTRODUCTION

The handling and processing of particles and powders is referred by the term of

particle technology. It is also often described as powder technology and powder

science. Among the industries that utilize this technology includes petrochemical,

chemical, pharmaceuticals, mineral processing and many more. In the production of

toluene, no solid formation is involved, however the only solid phase that is present is

in the third reactor, R103 when bromobenzene and bromomethane comes in contact

with the catalyst, isotope sodium-22 metal. The catalyst remains in and does not exit

the reactor. Hence, in the particle technology section, we will elaborate further about

the catalyst specifications and how the catalyst gets in contact with the reactants

(Rhodes. M. 2007).

47

7.2 CATALYST SPECIFICATION

7.2.1 Type Of Catalyst

Isotope sodium-22 is used as a catalyst in this toluene production plant. Below shows

the characteristics of the catalyst that we are using, isotope sodium-22. There are

several steps to consider during a catalytic reaction. Firstly, the transport of reactants

and energy from the bulk fluid to the exterior surface of the catalyst surface. Then the

transfer of the reactant and energy from the external surface into the porous catalyst

pellets occur. Further on, adsorption, chemical reaction and desorption of products

take place at the catalytic sites. The products from the catalyst interior is transported

to the external surface of the pellet. Finally the products are transferred into the bulk

fluid. The coupling of transport process and chemical reaction may lead to

temperature and concentration gradient within the catalyst pellet, between the surface

and the bulk or maybe even both. Below shows the hydrodynamic volume of the

catalyst characteristics of sodium-22 catalyst.

Figure 7.1 Hydrodynamic volume of the catalyst

Source : Rhodes. M., 2007.

Pores

Hydrodynamic

volume

Solid catalyst

48

Table 7.1 below shown is the characteristic of the catalyst used.

Table 7.1 Characteristic of sodium-22

Characteristic Description

Nuclide symbol 22

Na

Proton number 11

Nucleon number 11

Isotopic mass 21.9944364

Half life 2.6027 years

Decay mode +

Daughter isotope 22

Ne

Source : Sciencelab. 2003.

7.2.2 Catalyst Half-Life

It is vital to know the half-life of a catalyst. Half-life is defined as the amount of time

requirement for a quantity to fall to half its value as measured at the beginning of the

time period. Thus it is important to know how long it takes for the catalyst to decay

and to be replaced. Below shows the calculation for the half-life of isotope sodium-22

catalyst. This catalyst has a remarkable long half-life of 2.602 years. Based on our

plant which operates 300 days a year, this catalyst can be used up to 650 days. Below

shows the calculation for the half-life of the catalyst.

The initial weight of the catalyst 22.6 kg

The final weight of catalyst is hereby assumed to degrade 90% in weight.

Thus, the remaining catalyst weight 10% x 22.6 kg = 2.26 kg

Based on literature review, half-life of isotope sodium-22 catalyst is 2.602 years

equivalent to 950days

49

Elapsed time =

= 5390 days

Figure 7.2 below shows the graph of half-life of sodium-22 catalyst

Figure 7.2 Graph of half-life of isotope sodium-22

7.2.3 Properties Of Catalyst

In order to ensure that a catalytic process is commercially feasible, the number of sites

per unit reactor volume should be in a way that the rate of product formation is in the

order of 1 mol/L.hour. (P.B. Weisz.1973). Since a metal catalyst, isotope sodium-22 is

used, the metal is dispersed onto a high area oxide such as alumina. This can further

increase the surface area from 0.05 m2/g to greater than 100 m

2/g. The diameter of the

pellet ranges from 0.3-0.7 cm (Nob Hill Publishing, 2011).

0

5

10

15

20

25

0 1000 2000 3000 4000 5000 6000

Am

ou

nt

(kg)

Time(Days)

Graph of half-life of isotope Sodium-22

50

7.2.4 Catalyst Pore Property

The solid density is denoted by s. Since the pellet volume consists of both solid and

void regions, the pellet void fraction or also known as porosity is denoted by the sign

. Such that to calculate , we use the formula stated below.

= sVg

whereby s : pellet density

Vg : pore volume

Thus, based on the catalyst isotope sodium-22, the porosity of the catalyst is

=

] x

= 0.485

Since the pore structure is a crucial function of the preparation method, based on

literature review, the pore volume of a catalyst is said to range between 0.1-1 cm3/g

pellet. The pore size may be the same size or can be a bimodal distribution with pores

of two different sizes, a large size to help transport and a small size to contain the

active catalyst site. Besides that, pore size can also be as small as molecular

dimensions namely several angstroms or as large as several millimeters. The method

to determine the total catalyst area is by using a physically adsorbed species like

nitrogen gas, N2. This procedure was developed by Brunauer, Emmet and Teller and is

known as the BET theorem (S. Brunauer et al. 1938).

7.2.5 Catalyst Classification

Before choosing the type of group to classify the catalyst, several considerations must

be made to obtain the best choice. Firstly, since its a packed bed reactor, we first

calculate the superficial fluid velocity, since its a packed bed catalyst, then Umf = U.

Thus,

51

U =

=

= 6755.01m/s

Then we calculate superficial fluid velocity at minimum bubbling, Umb

Umb = 2.07exp(0.716F)

Umb = 2.07exp(0.716x (45 x 10-6

)

= 18130 m/s

We now see that U > Umb. Thus we can decide that the catalyst is classifies under

group C. Below shows the simplified diagram showing Geldarts classification of

powders according to their fluidization behavior in air under ambient conditions.

Figure 7.3 Geldarts Classification

Source : Kobayashi. T. et al. 2002.

52

Attached Table 7.2 below is the characteristics of group C powder.

Table 7.2 Characteristics of Group C powder

Characteristic Description

Obvious feature Cohesive and difficult to fluidize

Property bed expansion Low because of channeling

De-aeration rate Initially fast then exponential

Bubble properties No bubbles, only channels

Solid mixing Very low

Gas backmixing Very low

Spouting

Example

No

Flour, cement

Source : Rhodes. M., 2007.

It is said that group C powders are very fine powders and are cohesive in

nature. It is difficult for normal fluidization to occur for these solids due to strong

interparticle forces that are greater than those resulting from the action of the fluid.

Since group C particles are difficult to fluidize, they usually rise as plug of solids

where in larger diameter beds channel form from distributor to bed surface without

any fluidization of solids.

7.2.6 Fluid Flow Through Packed Bed With Catalyst

Since a packed bed reactor is used to host the main reaction, the catalyst pellets are

held in place and do not move with respect to a fixed reference time. The species

production rates in the bulk fluid is zero at first, therefore we use a catalyst to

complete the reaction. Essentially, all the reaction occurs inside the catalyst pellets.

The below diagram shows expanded view of catalysts in a packed bed reactor.

53

Figure 7.4 Expanded view of a catalyst in a packed bed reactor

Source : Nob Hill Publishing, 2011.

The symbols are denoted as

cj : Concentration on species j

cjs : Concentration of species j at the catalyst surface

T : Temperature

R : Gas constant

The flow of fluid through a packed bed of catalyst is governed by the relationship :

[pressure gradient] [liquid velocity] or

whereby is the pressure drop

H is the bed depth

U is the fluid volumetric flow rate

54

Hence, below shows the calculation to know the type of fluid flow through a packed

bed with catalyst isotope sodium-22.

Re =

Where:

Re = Reynolds number

D = diameter of the reactor(m)

= velocity of the reactant flow(m3/s)

= density of the reactant(kg/m3)

= viscosity of the reactant(kg/ms)

Re =

= 43233963.5

Since Re > 4000, thus we can conclude the fluid flow through packed bed with

catalyst is turbulent flow.

The flow of fluid through a packed bed of solid catalyst particles can be

analyzed in terms of the fluid flow through tubes. The starting point is the Hagen-

Poiseuille equation for turbulent flow through the tube is as shown below:

Where : fluid density

: fluid velocity

x : diameter of packed bed catalys

: void fraction of packed bed

55

To find H, rearrange the equation:

H =

= (101.3-200)kPa = -98.7 kPa

f = 1.495x103 kg/m

3

U = 21.67 m3/s

x = 0.2434

= 0.9649

So, H =

H = 0.5 m

Hence the depth of the packed bed is 0.5m.

The area of the packed bed is

2r2 + 2rh = 2[ x 0.752m] + 2[ x 0.75 x 0.5]

= 5.89 m2

The area of one catalyst pellet is

r2 = [0.005m] 2

= 7.85 x 10-5

m2

Thus, the amount if catalyst needed in the packed bed is

= 75031.85

Mass of catalyst needed

75031.85 x 23kg/kmol = 1725732.48 kg

56

Since the fluid flow is through tube with proposed cross sectional area of 1m2, we use

1725732.48 kg of isotope-22 catalyst with a bed depth of 0.5 m, the bed density is

= 3,451,464.97 kg/m

3

7.2.7 Catalyst Contact With Reactants

The packed bed reactor that we are using will have a top sprayer to disperse the

bromomethane gas onto bromobenzene liquid that will be flowed into the reactor via a

pipeline. Then both reactants come in contact with a packed bed catalyst spreaded

over alumina to increase surface area of contact.

The sprayer is used to ensure that the bromomethane is evenly distributed

throughout the reactor to get maximum coverage in contact with the bromobenzene

and catalyst. After contact with the catalyst, the desired product namely toluene is

formed and collected at the end of the reactor before being flowed to the next unit

operation. Below shows the cross sectional area of the packed bed reactor.

Figure 7.5 Cross sectional area of the packed bed reactor

57

Below shows the plot of fluid pressure loss across the bed versus superficial fluid

velocity through the bed.

Figure 7.6 Pressure drop versus fluid velocity for packed bed and fluidized bed

Source : Rhodes. M., 2007

Since in this process we are using a packed bed reactor, we only consider the region

OA. The solid catalysts do not move relative to another and their separation is

constant (Rhodes. M., 2007).

58

CHAPTER VIII

SEPARATION PROCESS

8.1 INTRODUCTION OF SEPARATION PROCESS

Based on the process flow diagram, it is seen that the process design has four main

unit operations that are used to separate various components thus obtaining the desired

product which is toluene. Table 8.1 below shows a short description of the separation

units used to separate the components.

Table 8.1 Separation units in process flow diagram

Unit Separation Description Phases of components

D101 Distillation Column Separates Bromobenzene

and Hydrogen Bromide

Bromobenzene (l)

Hydrogen bromide (g)

G101 Gas Permeation

Membrane

Separates Bromomethane

and Hydrogen

Bromomethane (g)

Hydrogen (g)

59

P101 Phase Separator Separates Toluene from

Bromine, Bromomethane

and Bromobenzene

Bromine (g)

Bromobenzene (l)

Bromomethane(g)

Bromine (g)

Toluene (l)

D102 Distillation Column Further separates Toluene

from Bromobenzene

Toluene (l)

Bromobenzene (l)

8.2 GAS PERMEATION MEMBRANE (G101)

Bromomethane and hydrogen are in gaseous phase and needs to be separated because

bromomethane has to be supplied to the third reactor R103 to produce the desired

product, toluene. Gas permeation membrane is chosen as the most suitable gas

separation unit because a high purity of bromomethane can be obtained.

A membrane can be defined as a selective barrier between two fluid phases.

Gas separation process needs a membrane with high permeability and selectivity.

Membranes can be classified into two categories namely symmetrical and

asymmetrical. Figure 8.1 below shows the membrane classification.

Figure 8.1 Membrane Classification

Source : Abedini R. 2010.

Membrane Classification

Symmetrical

- Homogenous (dense)

- Porous

- Cylindrical Porous

Assymetrical

- Porous

-Porous with dense top layer

- Composite

60

8.2.1 Membrane Selection

For our system design we choose to use an asymmetrical porous with dense top layer

polymeric membrane. This type of membrane has a high selectivity property towards

the type of gases that needs to be separated. Hydrogen is one of the smallest molecule

with a bond length of 0.74. Bromomethane is a larger molecule compared to

hydrogen bromide with a bond length of 1.930+0.003. An important property of a

porous dense membrane is that even permeates of similar sizes may be separated

easily. These membranes are elastomers from cross linked copolymers of high

molecular weights. They are then prepared as thin films by extrusion or casting. It

demonstrates a high unique permeability property with high selectivity towards H2.

Hence, our desired product, bromomethane can be obtained since the membrane has a

high selectivity towards hydrogen gas. Table 8.2 below shows the characteristics of

the non-porous dense polymeric membrane.

Table 8.2 Characteristics of non-porous dense polymeric membrane

Characteristics Description

Type of material

Additives

Length

Polyetherimide (PEI)

Polybenzimidazole (PBI) and

Poly(ethylene glycol) (PEG600)

5-10m

Thickness of dense skin

Porous support thickness

Method of preparation

Operating temperature

1000

25-100m

Extrusion, solvent casting or

impregnation

30C

Thermal Stability 250C

Biodegradability Biodegradable

61

Source : Abedini. R. 2010.

8.2.2 Mechanism Of Gas Transport Mechanism

Among the established gas transport mechanisms include the Poiseuille flow,

Knudsen diffusion, molecular diffusion, capillary diffusion, surface diffusion and

solution diffusion. Figure 8.2 below shows the schematic representation of major gas-

transport mechanisms in membranes.

Figure 8.2 Schematic representation of major gas-transport mechanism

Source : Shao. L. et al. 2008

Usually in porous membranes, Poiseuille flow or Knudsen diffusion dominates mostly

the overall gas transport. However, Knudsen diffusion is majorly used if the pore size

of the membrane is smaller that 50nm, however in our case, the proposed membrane

has a size 25-100 m. The propertiy of Knudsen flow is governed by the ratio of the

pore radius (r) to the mean free path () of the gas molecule. If the /r

62

8.2.3 Type Of Equipment For Gas Permeation Membrane Process

A structure of hollow fiber membrane is chosen to separate bromomethane and

hydrogen. Their modular structure proves to separate gas efficiently. (Jay.M.S. 1981).

The membranes have the shape of very small diameter hollow fibers. The hollow

fibers looks like a shell-and-tube heat exchanger. Thousands of fine tubes are bounded

together in a tube sheet. The tube sheet is surrounded by a metal shell. A high pressure

feed is fed into the shell inlet and leaves at the other end. The hollow tubes remain

enclosed at one end of the tube bundles. The permeate gas inside the fiber flows to the

shell-tube and is collected in a chamber where the open ends of the fibers terminate.

Hence, the permeate exits the membrane. Figure 8.3 below shows the structure of a

hollow-fiber membrane (Geankoplis C.J. 2003).

Figure 8.3 Structure of a hollow-fiber membrane

Source : KOCH membrane system. 2013.

A hollow fiber membrane have several specification and caters for molecules that

suits the specification. Thus Table 8.3 below shown the specifications of the hollow-

fiber membrane.

63

Table 8.3 Specifications of hollow-fiber membrane

Specification Description

Inside diameter 200 m

Outside diameter 400 m

Metal shell diameter 6 m

Metal shell length 3 m

Source : Geankoplis C.J. 2003.

8.2.4 Type Of Flow In Gas Permeation Membrane

There are several types of flow in a gas permeation membrane. For example complete

mixing, cross flow, countercurrent flow and concurrent flow. Based on this design, we

propose a complete mixing flow. Since high pressure is fed at the inlet of the

membrane, the permeate leaves in a direction normal to the membrane, thus

accumulating on the lower pressure side of the membrane. Due to high diffusion

coefficient in gases, concentration gradient in the gas phase in the direction normal to

the surface of the membrane is quite small. Thus gas film resistance compared to

membrane resistance is neglected. Hence, a complete mixing flow is assumed for the

feed and permeate chamber. Figure 8.4 below shows the ideal flow pattern in a

membrane separator, the highlighted region depicts a complete mixing flow pattern

that is chosen for our membrane.

64

Figure 8.4 Ideal flow patterns in a membrane separator for gases : (a) complete

mixing, (b) cross-flow, (c) countercurrent flow, (d) concurrent flow.

Source : Geankoplis C.J. 2003.

8.2.5 Membrane Design

A membrane is to be used to separate a gaseous mixture of bromomethane(A) and

hydrogen gas(B). The details and calculation is as follow.

Feed flow rate,Lf = 40.626 x106 cm

3(STP)/s