Final Thesis Babar

Production of 650 ton/day Para-Xylene from
Methylation of Toluene
Session (2014-2018)
Author
Name Registration No
Asad Ali 2014-CH-422
Babar Javed 2014-CH-404
Munawar Hussain 2014-CH-419
Sabir Hussain 2014-CH-410
SUPERVISED BY:
Dr. Ayyaz Ahmad (Assistant Professor)
DEPARTMENT OF CHEMICAL ENGINEERING

MUHAMMAD NAWAZ SHARIF UNIVERSITY OF
ENGINEERING AND TECHNOLOGY
MULTAN
July 2018
Production of 650 ton/day Para-Xylene from Methylation of Toluene
Author
Name Registration No.

Asad Ali 2014-CH-422
Babar Javed 2014-CH-404
Munawar Hussain 2014-CH-419
Sabir Hussain 2014-CH-410
A thesis submitted in partial fulfillment of the requirement for the degree of
B.Sc. in Chemical Engineering
Thesis Supervisor:
Dr. Ayyaz Ahmad

Assistant Professor
External Examiner’s Signature:___________________________________________
Thesis Supervisor’s Signature:____________________________________________
_________________________
Dr. Asim Umer
Project Incharge / Head of Department
(Chemical Engineering)
DEPARTMENT OF CHEMICAL ENGINEERING

MUHAMMAD NAWAZ SHARIF UNIVERSITY OF
ENGINEERING AND TECHNOLOGY, MULTAN
July 2018
I
ABSTRACT
Toluene and Methanol are used for the production of Para-Xylene. The main objective of this
project report is to deal with design calculations of 650 tons/day of Para-Xylene production
along with its relevant aspects such as Manufacturing Process, Material Balance and Energy
Balance, Equipment Design, Cost Estimation, Simulation, Instrumentation, HAZOP study and
Environmental aspects. Para-Xylene is an important industrial compound, and its demand has
been increasing in recent years. It is mostly produced from cracking of naphtha, but there is a
need for new and cost-effective methods for the production. High p-xylene selectivity in the
reactor and use of reactive distillation reduces the separation cost and renders the new process
economically competitive. Para-Xylene is used as a basic raw material in the production of
PTA (Purified Terephthalic Acid). PTA is produced by oxidation of p-xylene. Lotte Chemicals
Pakistan Limited is a sole producer of PTA, an essential raw material for Polyester Staple Fibre
(PSF), Polyester Filament Yarn (PFY), and Polyethylene Terephthalate (PET) resin. Pakistan
usually imports all of the required amount of para-xylene for industrial usage as there is no
industry in Pakistan for the production of Para-Xylene. According to these facts this project is
very useful to save our economy and to get all the gradients from our country for the
manufacturing of the products.
II
UNDERTAKING
I certify that thesis work titled “Production of 650 ton/day Para-Xylene from Methylation of Toluene”
is our own work. The work has not been presented elsewhere for assessment. Where Material has been
used from other sources it has been properly acknowledged / referred.
Name (Registration No) Signature
Asad Ali (2014-CH-422) ________________________________
Babar Javed (2014-CH-404) ________________________________
Munawar Hussain (2014-CH-419) ________________________________
Sabir Hussain (2014-CH-410) ________________________________
III
ACKNOWLEDGEMENTS
All praise to Almighty ALLAH, who provided us with the strength to accomplish this project
report. All respects are for His HOLY PROPHET (Peace Be Upon Him), whose teachings are
true source of knowledge & guidance for whole mankind.
Before anybody else we thank our Parents who have always been a source of moral support,
driving force behind whatever we do. We are indebted to our project advisor Dr. Ayyaz
Ahmad for his worthy discussions, encouragement, technical discussions, inspiring guidance,
remarkable suggestions, keen interest, constructive criticism & friendly discussions which
enabled us to complete this report.
We are thankful to the Head of Department and Project Incharge Dr. Asim Umer for providing
facilities and guidance. We are also thankful to all of our teachers for their keen and sincere
efforts and suggestions that proved to be very helpful in achieving our goal.
IV
“Dedicated to our beloved parents and respected teachers whose
tremendous support and cooperation led us to this wonderful
Accomplishment.”
V
Table of Contents
CHAPTER # 01 INTRODUCTION ............................................................................... 1

1.1. Introduction ..................................................................................................................... 1
1.2. Para-Xylene Properties .................................................................................................... 1
1.3.Applications of Para-Xylene ............................................................................................ 1
1.4. World Wide Demand ...................................................................................................... 2
1.5. World Wide Demand and Consumption ......................................................................... 3
1.6. Para-Xylene Demand in Pakistan.................................................................................... 3
1.7. Para-Xylene Import Data for Pakistan ............................................................................ 4
1.8. Capacity Selection ........................................................................................................... 4
CHAPTER # 02 LITERATURE REVIEW AND PROCESS SELECTION ............. 5

2.1. Available Production Methods for Para-xylene .............................................................. 5
2.2. Description of Available Processes ................................................................................. 5
2.3. Comparison of Available Processes ................................................................................ 6
CHAPTER # 03 PROCESS DESCRIPTION ............................................................... 7

3.1. Pump (P-100,P-101,P-102,P-103)................................................................................... 7
3.2. Heat Exchanger (H-100, H-101, H-102, H-103)............................................................. 7
3.3. Reactor R-100 ................................................................................................................. 7
3.4. Flash Column V-100 ....................................................................................................... 9
3.5. Three Phase Separator ..................................................................................................... 9
3.6. Distillation Column (D-100, D-101, D-102, D-103, D-104) .......................................... 9
CHAPTER # 04 MATERIAL BALANCE ................................................................. 10

4.1. Components Involved ................................................................................................... 10
4.2. Reactor (R-100) ............................................................................................................. 10
4.3. Flash Vessel (V-100) ..................................................................................................... 12
4.4. Decanter (D-100)........................................................................................................... 13
4.5. Distillation Columns ..................................................................................................... 14
4.5.1. Distillation (DC-100) ................................................................................................. 15
4.5.2. Distillation (DC-101) ................................................................................................. 15
4.5.3. Distillation (DC-102) ................................................................................................. 17
4.5.4. Distillation (DC-103) ................................................................................................. 18
4.5.5. Distillation (DC-104) ................................................................................................. 19
4.6.Overall Plant Material Balance ...................................................................................... 20
CHAPTER # 05 ENERGY BALANCE ...................................................................... 21

5.1. Energy Balance across Reactor (R100) ......................................................................... 21
VI
5.1.1. Reactions and Conversion .......................................................................................... 22
5.2. REACTOR (R100) ........................................................................................................ 24
5.3. Energy Balance across Heat Exchanger (H-100) .......................................................... 25
5.4. Energy Balance across Flash Vessel (V-100) ............................................................... 26
5.5. Energy Balance across Distillation Column (DC-100) ................................................. 27
CHAPTER # 06 EQUIPMENT DESIGN ................................................................... 33

6.1. Reactor Design (R-100) ................................................................................................ 33
6.2. Mechanical Design of Reactor………………………………….……………………..39
6.3. Heat Exchanger Design (H-100) ................................................................................... 44
6.3.1. Shell & Tube Heat Exchangers .................................................................................. 44
6.4. Design of Distillation Column (DC-100) ...................................................................... 48
6.5. Design of Flash Column (V-100) .................................................................................. 59
6.5.1. Design Calculations.................................................................................................... 59
6.5.2. Area (A)...................................................................................................................... 60
6.5.3. Diameter (D) .............................................................................................................. 60
6.5.4. Volume (V) ................................................................................................................ 60
CHAPTER # 07 COST ESTIMATION ...................................................................... 62

7.1.Cost Estimation of Reactor ............................................................................................ 62
7.2. Cost of distillation Column: .......................................................................................... 63
7.3. Cost of Flash Column.................................................................................................... 63
7.4. Cost of Heat Exchanger................................................................................................. 64
7.5. Cost of Mixer ................................................................................................................ 64
7.6. Cost of Decanter ............................................................................................................ 65
7.7. Total Cost of the Plant................................................................................................... 65
CHAPTER # 08 PROCESS SIMULATION .............................................................. 69

8.1. Introduction to Process Simulation and Aspen HYSYS ......................................................... 69
8.2. Simulation procedure………………………………………………………………… 69
8.3. Simulation Results ............................................................................................................................. 70
8.3.1. Process Flow Diagram ............................................................................................... 76
8.3.2. Conversion Reactor (To validate material balance) ................................................... 76
8.3.3. Conversion Reactor (To validate material balance) ................................................... 77
CHAPTER # 09 HAZOP STUDY ............................................................................... 78

9.1.HAZOP Study for Distillation Column (DC-100) ......................................................... 78
CHAPTER # 10 INSTRUMENTATION AND CONTROL ..................................... 80

10.1. Control Loops .............................................................................................................. 80
10.2. Components of a control system ................................................................................. 80
CHAPTER # 11 ENVIRONMENTAL IMPACT ASSESSMENT ........................... 82

11.1. Project Outline............................................................................................................. 82
11.2. Site Selection ............................................................................................................... 82
VII
11.3. Cooling-Water Technology ......................................................................................... 83
11.4. Description of the Environment .................................................................................. 83
11.5. Study Area ................................................................................................................... 83
11.6. Physical Baseline......................................................................................................... 84
REFERENCES ....................................................................................................................... 93
VIII
List of Figures
Figures……………………………………………………………Page Number
Figure 1.1: Applications of p-Xylene…………………………………...………………….2
Figure 1.2: p-Xylene Demand……………………………………………..……………….3
Figure 1.3: Worldwide demand and consumption…………………………..……………..3
Figure 3.1: Process Flow Diagram…………………………………………...………….…8
Figure 4.1: Reactor (R-100)…………………………………………………...…………..11
Figure 4.2: Flash Vessel (V-100)……………………………………………...…………..13
Figure 4.3: Decanter (D-100)…………………………………………………...…………14
Figure 4.4: Distillation (DC-100)………………………………………………...………..15
Figure 4.5: Distillation (DC-102)………………………………………………...………..16
Figure 4.6: Distillation (DC-102)………………………………………………..……...…18
Figure 4.7: Distillation (DC-103)………………………………………………..………...19
Figure 4.8: Distillation column (DC-104)………………………………………..………..20
Figure 5.1: Reactor R-100……………………………………………………….....……...24
Figure 6.1: Reactor configuration…………………………………………………..……...34
Figure 6.2: q-line for different feed conditions…………………………………………….49
Figure 6.3: Salculation by McCabe and Thiele…………………………………………….50
Figure 8.1: Simulation results for pumps…………………………………………………...70
Figure 8.2: Simulation results for heater……………………………………………………71
Figure 8.3: Simulation results for mixer……………………………………………..……..71
Figure 8.4: Simulation results for plug flow reactor………………………………………..72
Figure 8.5: Simulation results for cooler……………………………………………………73
Figure 8.6: Simulation results for flash column…………………………………………….73
Figure 8.7: Simulation results for 3-phase separator………………………………………..74
Figure 8.8: Process flow diagram…………………………………………………………...75
Figure 8.9: For conversion reactor (to validate material balance)…………………………..75
Figure 8.10: For conversion reactor (to validate material balance)…………………………76
Figure 10.1: Feedback control loops on distillation column………………………………...80
IX
Figure 11.1: The submerged coastline 600 m south of the project-site overlooking gharo
creek………………………………………………………………………………………….83
Figure 11.2: Badal nullah flowing 1 km west of the project-site into the gharo creek………84
Figure 11.3: Badal nullah flowing from the northerly direction ………… …………………84
X
List of Tables
Tables………………………………………………………..………Page
Number
Table 1.1: All properties are at ambient temperature (25 0c) and pressure (1atm)…….…….1
Table 1.2: para-xylene import data for Pakistan………………………………………..……4
Table 2.1: Processes available for the manufacturing of p-xylene……………………………5
Table 2.2: Comparison of available processes………………………………………………..6
Table 4.1: Components involved in material balance…………………………………...…...10
Table 4.2: Reactor balance…..……………………………………………………………….11
Table 4.3: Temperature and fraction calculations at fixed pressure……………………...…..13
Table 4.4: Flash vassal balance……………………………………………………………....13
Table 4.5: Decanter balance…………..…………………………………………………..….14
Table 4.6: DC-100 balance………………………………..…………………………….……15
Table 4.7: DC-101 balance…………………………………………………..……………….17
Table 4.8: DC-102 balance………………………………………………………………...…18
Table 4.9: DC-103 balance……………………………………………………………..…….19
Table 4.10: DC-104 balance…………………………………………………...……………..20
Table 4.11: Overall plant material balance…………………………………………..………20
Table 5.1: Cp value calculations for gases…………………………………………………...21
Table 5.2: Standard heat of formation…………………………………………………….….22
Table 5.3: Reactor heat calculations………………………………………………………….24
Table 5.4: Cp value calculations for liquids………………………………………………….25
Table 5.5: Cp value calculations for gases…………………………………….……………..25
Table 5.6: Heat duties calculations for heat exchanger………………………………………26
Table 5.7: DC-100 energy calculation data……………………………………………..……27
Table 5.8: data for bubble point calculation of DC-100…………………………………...…27
Table 5.10: streams of DC-100……………………………………………………………....30
Table 5.11: Duties of distillation column DC-100………………………………………..….31
Table 6.1: Selection of distillation column………………….…………………………….…33
Table 6.2: Selection of the head……………………………………………………….….….39
XI
Table 6.3: Specification sheet and design data for reactor……………………………….…43
Table 6.4: Specification sheet for heat exchanger…………………………………………..47
Table 6.5: Tray selection of tray in distillation column…………………………………..…57
Table 6.6: Specification sheet for vertical flash separator…………………………………..62
Table 9.1.HAZOP (18) study for distillation column (DC-100)……………………………79
Table 11.1: Types of vehicles observed on roads near the project-site……………………..75
Table 11.2: Socioeconomic aspects and survey results………………………………….….87
XII
Chapter # 01
Introduction
1.1. Introduction
Xylenes are aromatic carbons in which two carbons are attached at benzene ring. There are
three types of xylenes. They are o-Xylene, m-Xylene, and p-Xylene. In these xylenes the
carbon groups are attached at ortho, meta and para positions.
1.2. Para-Xylene Properties
Table 1.1: All properties are at ambient temperature (25 0C) and pressure (1atm)
Property Name Value

Molecular weight 106.168
(kg/kgmol)
Freezing point (oC ) 13.2
Boiling point (oC ) 138.3
Melting point (oC) 13.2
Form and colour Colourless and liquid
Density (kg/m3 ) 861
1.3.Applications of Para-Xylene
1. Used as a basic raw material in the manufacture of dimethyl terephthalate (DMT) and
teraphathalic acid (TPA).
2. Used in plastic and rubber products.
3. Small amount used as solvents, coatings or pesticides.
1
4. TPA is used in the production of polyethylene terephthalate (PET).PET is used to
produce polyester fiber and PET bottles (1).
Figure 1.1: Applications of Para-Xylene
1.4. World Wide Demand
Xylenes are used for cleaning in electroplating, paper coating, pharmaceuticals, rubber
manufacturing, varnishing, and are abundantly use for solvents.
Para Xylene has a lot demand in the world than the other isomers.
o-xylene m-xylene p-xylene
18%
24% 23%
2%
80% 53%
Demand
Figure 1.2: Para Xylene demand
P-Xylene is more important than the other isomers because it is used as a raw material for many
other components.
 Para-Xylene market demand has increased over the years. Because of high demand,
Para-Xylene generally has 6-8% yearly demand growth.
 Factor for increase in demand is the price of cotton. Market for polyester fiber is now
substantially larger than that of cotton.
2
 The global demand for para-xylene has been steadily increasing, and this growth is
expected to continue (2).
1.5. World Wide Demand and Consumption
Figure 1.3: World Wide Demand and Consumption (3)
1.6. Para-Xylene Demand in Pakistan
 Para-Xylene is used as a basic raw material in the production of PTA. PTA is produced
by oxidation of Para-Xylene
 Lotte Chemicals Pakistan Limited is a sole producer of Purified Terephthalic Acid

(PTA), an essential raw material for Polyester Staple Fiber (PSF), Polyester Filament
Yarn (PFY), and Polyethylene Terephthalate (PET) resin.
 The capacity of plant is 500,000 tons/year of PTA.
 The para xylene required for 1 ton of A PTA product under world average conditions
is 0.67 ton.
3
1.7. Para-Xylene Import Data for Pakistan
Table 1.2: Para-Xylene Import Data for Pakistan

Year p-xylene Ton/day
import(kg/day)
2012 313607496 859.1986
2013 313040876 857.6462
2014 258263251 707.5706
2015 158731559 434.881
2016 149940924 410.7971
Average 238716821.2 654.0187
1.8. Capacity Selection
 The demand of Para-Xylene is varying according to the demand and uses. So, for the
next coming years we use the average of the imported Para-Xylene for our plant
capacity selection
 As the average import is 654 ton per day. So our one day production will be 650 ton
per day (4).
4
Chapter # 02
Literature Review and Process Selection
2.1. Available Production Methods for Para-xylene
1. Catalytic reforming of naphtha.

2. Toluene disproportionation.
3. Methylation of toluene
2.2. Description of Available Processes

Table 2.1: Processes available for the manufacturing of p-Xylene (6)
Catalytic Reforming of Toluene Methylation of Toluene

Naphtha Disproportionation
1. Catalytic reformate 1. In toluene 1. By reacting toluene
is produced by disproportionation and methanol over a
contacting petroleum two molecules of zeolite catalyst, such
naphtha with toluene react over an as ZSM-5, water and
dehydrogenation on acid zeolite catalyst p-xylenes are formed.
catalyst on a support. to form one xylene
2. A C6 to C8 fraction and one benzene
is separated from molecule.
reformate to produce 2. Para xylene is
a mixture of aromatic separated from
compounds. xylene mixture by
3. This mixture of crystallization or
aromatic compounds adsorption process.
is composed of
benzene, toluene and
xylenes (BTX).
5
2.3. Comparison of Available Processes
Table 2.2: Comparison of available processes
Process for
Sr.# p-Xylene Advantages Disadvantages
Production
With the fast growing 2.This method produce a dilute
demand in aromatics and mixture of p-xylene with other
demand of high - octane unimportant isomers, m-xylene and o-
numbers, catalytic xylene, along with ethyl benzene (EB)
reforming is likely to 2. Separation is very difficult because
1. Catalytic remain one of the most the products and byproducts have very
reforming of important unit processes in close boiling points.
Naphtha the petroleum and 3. To increase the volume production
petrochemical industry. the unimportant isomers o-xylene and
m-xylene are converted to p-xylene by
isomerization. Consequently the cost
of production increases.
This process also produces 1. Catalyst deactivate quickly due to

benzene; therefore it is coke formation on catalyst.
Toluene feasible when benzene is 2. Low selectivity for p-xylene.
2. disproportionation also required along with the 3. Coking of catalyst reduces the
xylenes. overall conversion of reactant to
product.
1.In this process the

selectivity of the p-xylene is
97.5 % which is more
suitable for industries
2. P-Xylene is purified to
99.8% with the extensive 1. The conversion of toluene and
3. Methylation of and extractive distillation methanol is very less.
toluene than the other conventional 2. About 40% consumes to the side
processes like the reaction.
crystallization and
adsorption.
3. It is cost efficient as
compare to other processes.
4. Minimum coking during
the reaction in the reactor.
2.3.1Selection of the Process
 Methylation of toluene gives P-xylene selectivity of 97.5% and purity of 99.8%.Also it

is cost efficient process. So we selected it (3).
6
Chapter # 03
Process Description
3.1. Pump (P-100,P-101,P-102,P-103)
This pump is used to pump the toluene from the storage tank towards the heat
exchanger. As 3bar pressure is required in the reactor so this pump pumps the liquid toluene to
3 bar pressure. Pump P-101 also pumps the methanol at the pressure of 3 bar which is required
in the reactor.
Pump P-102 is used after the decanter, which is used to increase the pressure of the A-
11 stream. This pressure is required in the distillation column DC-100.
Pump P-103 is used to increase the pressure of the stream A-10 to 8 bar pressure, which is
required in the distillation column D-101.
3.2. Heat Exchanger (H-100, H-101, H-102, H-103)
Heat Exchanger H-100 is used to increase the temperature of the toluene stream up to
4000C. This temperature is required in the reactor to get the maximum product of the p-xylene.
Heat Exchanger H-101 is used to increase the temperature of the methanol stream up
to 4000C. This temperature is required to enhance the purity of the p-xylene.
H-102 is used after the reactor which is used to decrease the temperature of the product
from the reactor. This stream is further installed in the flash column, where less temperature is
required to remove the ethylene from the other components.
H-103 is working to increase the temperature of the streams coming from the distillation
columns, where the toluene and methanol are present. These streams are added in the mixed
M-100 where 3 bar pressure is required. The temperature is increased up to 4000C which is
required in the reactor.
3.3. Reactor R-100
Packed bed reactor PBR-100 is the primary block of the procedure glide sheet. It
operates on the equal conditions. Feed to the reactor is a mixture of fresh substances and
toluene and methanol recycle flow A-19. The combined feed circulation to the reactor is A-
7
Figure 3.1: Process Flow Diagram
8
5 and the product movement is A-6. Catalyst used is Mg ZSM-5 giving Wcat/FTo ratio of two.
Five primarily based on a thousand kmol/hr of toluene in A-5. A catalyst mattress void fraction
of 0.35 has been used.
The reactor residence time is 0.267 sec.The heat needs to be removed to maintain the
temperature at four hundred 0C. For this purpose a shell and tube kind reactor is usually
recommended wherein catalyst is inside the tubes and on the shell aspect cooling media flows.
This massive quantity of strength generated can be used for the energy requirement of
the technique with the aid of steam technology.
3.4. Flash Column V-100
This column is used to separate the dissolved gases present in the product of the
distillation column. In this column we are separating ethylene from the other components
present in the stream A-7. Up to 85% of ethylene is removed here.
3.5. Three Phase Separator
In this equipment the fluid is separated on the basis of the densities. The main purpose
of this equipment is to remove the stream of methanol and water from the other stream which
is further introduced in the distillation columns. Ethylene is also removed in this separator.
3.6. Distillation Column (D-100, D-101, D-102, D-103, D-104)
The main purpose of distillation is to separate the different liquid streams on the basis
of the boiling points.D-100 is a binary distillation column, which is used to separate the stream
on methanol and water at 4 bar pressure.
D-101 is a multi-component distillation column which is operated at 8 bar pressure with 500C
temperature at feed.
D-102 is also a multi-component distillation column which is operated at 3 bar pressure.
D-103 is an extractive distillation column. As the boiling point of p-xylene and o-xylene
is close to each other, so for the extraction of these liquids we use and other stream in it which
increases the boiling point difference of these steams and the product is extracted.
D-104 is operated at 0.4 bar pressure. This is a packed column where the final pure p-
xylene is extracted.
9
Chapter # 04
Material Balance
4.1. Components Involved
(7) (8)
Table 4.1: Components involved in material balance
Components Formula Molecular Boiling Points (oC)

Weights (g/mole) at 1 bar
p-xylene C8H10 106.168 138.3
Benzene C6H6 78.114 80.1
Toluene C7H8 92.141 110.6
Methanol CH3OH 32.042 64.6
Water H2O 18.015 100
m- xylene C8H10 106.168 139.1
o-xylene C8H10 106.168 144.4
Ethylene C2H4 28 - 104
Di-tertiary Butyl Benzene C14H22 190 230
Tertiary-Butyl m-Xylene C12H18 162 205
4.2. Reactor (R-100)
4.2.1. Material Balance Steps for Reactor
1. Select suitable basis.
2. Degree of freedom analysis.
3. Apply material balance equation for reaction.
4. Use ratio method to calculate amount of reactants and products by using conversions
of every reaction.
5. Determine the compositions of products.
Reactor Conditions
Operating Temperature = 400 o C
10
Operating Pressure = 3 bar
Basis
1900 kmol/hr or 136800 kg/hr (A5)
Figure 4.1: Reactor (R-100)
Feed Molar Ratio (3)
Toluene : Methanol
2 : 1
Main Reaction
CH3OH (Methanol) + C7H8 (Toluene) C8H10 (p-X) + H2O
(23% overall conversion of Toluene from which 83% convert into p-X and 17%
loss to side reaction)
Side Reactions
1. 2 CH3OH C2H4 (Ethylene) + 2 H2O
(40% of Methanol fed is converted in this reaction)

2. C7H8 (Toluene) ½ C6H6 (Benzene) + ½ C8H10 (p-X)
(17% of 23% Toluene is converted in this reaction)
3. C8H10 (p-X) ½ C8H10 (o-Xylene) + ½ C8H10 (m-Xylene)
(2.53% of p-X is converted to o-X and m-X) (3)
4.2.2. Reactions and Conversions
Table 4.2: Reactor Balance
Component Inlet(A5) (kg/hr) Outlet(A6) (kg/hr)

p-xylene - 27607.94
Benzene - 1931.54
Toluene 116533.3 89730.67
Methanol 20266.67 4422.187
Water - 8912.52
m- xylene - 324.2386
o-xylene - 324.2386
Ethylene - 3546.667
Total 136800 136800
11
4.3. Flash Vessel (V-100)
4.3.1. Material Balance Steps for Flash Vessel (9) (10)
1. Use the Antoine equation to calculate the saturated pressure of each component.
2. Find k values of each component.
3. Maintain temperature for desired separation.
4. Calculate the bubble pressure and dew pressure of mixture.
5. For bubble pressure , with Σ𝑦𝑖 = 1, use 𝑃 = Σ𝑥𝑖 𝑃𝑖𝑠𝑎𝑡
1
6. For dew pressure , with Σ𝑥𝑖 = 1, use 𝑃 = Σ𝑦 / 𝑝𝑠𝑎𝑡
𝑖 𝑖
7. Select any pressure (ranges between bubble pressure and dew pressure) and calculate
the fraction of feed vaporized (f) by iterations.
𝑥
𝐹𝑖
8. Calculate the bottom compositions by Σ𝑥𝑤𝑖 = Σ (𝑓(𝑘 −1)+1)
𝑖
9. Calculate the top (vapor) compositions by Σ𝑦𝑖 = Σ(𝑥𝑤𝑖 𝑘𝑖 )
10. Make iterations by reducing pressure (repeat step 7,8,9 for each iteration) and to
obtain the desired separation.
Conditions
Operating Pressure = 0.733 bar
Figure 4.2: Flash Vessel (V-100)
12
Table 4.3: Temperature and fraction calculations at fixed pressure:
P-Xylene Benzene Toluene Methanol Water m-Xylene o-xylene Ethylene
A 6.99052 A 15.9037 A 16.0053 A 16.6104 A 18.5882 A 6.996 A 7.00154 A 6.74756
1 2
B 1453.43 B 2789.01 B 3090.78 B 3392.57 B 3984.92 B 1469.91 B 1476.39 B 585
3
C 215.307 C 220.79 C 219.14 C 230 C 233.43 C 214.589 C 213.872 C 255
Temp 50 Tem 50 Tem 50 Tem 50 Tem 50 Tem 50 Tem 50 Tem 50

p p p p p p p
ln(p1 sat) 1.51222 5.60416 4.52139 4.49409 4.52857 1.44055 1.40642 4.82952
5 9 8 9 3 4 9 7
P1 Sat 4.53681 271.556 91.9641 89.4874 92.6263 4.22303 4.08135 67534.7
(mmHg) 4 2 7 2 3 7 4
P (mmHg) 550 550 550 550 550 550 550 550
P (bar) 0.73333 0.73333 0.73333 0.73333 0.73333 0.73333 0.73333 0.73333

3 3 3 3 3 3 3 3
k1 0.00824 k2 0.49373 k3 0.16720 k4 0.16270 k5 0.16841 k6 0.00767 k7 0.00742 k8 90
9 8 7 4 1 8 1
F 0.06293 0.06293 0.06293 0.06293 0.06293 0.06293 0.06293 0.06293
Xf1 0.1285 Xf2 0.01221 Xf3 0.48128 Xf4 0.06816 Xf5 0.2443 Xf6 0.00150 Xf7 0.00150 Xf8 0.06249
7 9 9
Xw1 0.13705 Xw2 0.01261 Xw3 0.50789 Xw4 0.07195 Xw5 0.25779 Xw6 0.00161 Xw7 0.00161 Xw8 0.00946
4 9 8 1 1 7
Table 4.4: Flash Vassal balance (11)

Component Inlet (kg/hr) Outlet (kg/hr)
A7(Feed) A8(Top) A9(Bottom)
p-xylene 27607.94 15.28328 27589.21
Benzene 1931.54 61.98085 1869.278
Toluene 89730.67 996.4565 88739.85
Methanol 4422.187 47.77476 4372.554
Water 8912.52 100.8128 8812.374
m- xylene 324.2386 0.164932 324.1053
o-xylene 324.2386 0.159525 324.1053
Ethylene 3546.667 3042.657 503.0412
Total 136800 4265.289 132534.5
136800 136800
4.4. Decanter (D-100) (9)
Conditions
13
Figure 4.3: Decanter (D-100)
Table 4.5: Decanter balance

A9 A11 A10
p-xylene 27589.21 - 27589.21
Benzene 1869.278 - 1869.278
Toluene 88739.85 - 88739.85
Methanol 4372.554 4372.554 -
Water 8812.374 8812.374 -
m- xylene 324.1053 - 324.1053
o-xylene 324.1053 - 324.1053
Ethylene 503.0412 - 503.0412
Total 132534.5 13184.93 119349.6
132534.5 132534.5
4.5. Distillation Columns
4.5.1. Material Balance steps for Distillation Column
1. Make suitable assumptions to complete the degree of freedom.
2. Apply component balance for each component.
3. Apply overall balance of column to find D and W.
4. Calculate the amount of distillate and bottom product and their compositions.
14
4.5.2. Distillation (DC-100)
Conditions:
Figure 4.4: Distillation (DC-100)
Assumptions:
1. 99% methanol goes to top product and 99% of water goes to bottom
Table 4.6: DC-100 balance (11) (12)
A11(Feed) A12(Bottom) A13(Top)
p-xylene - - -
Benzene - - -
Toluene - - -
Methanol 4372.554 43.72554 4328.828
Water 8812.374 8724.25 88.12374
m- xylene - - -
o-xylene - - -
Ethylene - - -
Total 13184.93 8767.976 4416.952
13184.93 13184.93
Conditions

15
Assumptions
1. All LNK goes to top product and all HNK goes to bottom.
2. 99% benzene goes to top product and 99% of toluene goes to bottom

For top section
Para-xylene (1), Benzene (2) , Toluene (3) , m-Xylene (4) , o-Xylene (5) , Ethylene (6)
𝐷𝑥2 , 𝑑 = 0.99 × 1869.278 = 1850.585 𝑘𝑔/ℎ𝑟
Remaining 1% in top is containing toluene and ethylene from which ethylene is
𝐷𝑥6𝐷 = 503.0412 𝑘𝑔/ℎ𝑟
𝐷𝑥5𝑑 = 0
𝐷𝑥4𝐷 = 0
𝐷𝑥1𝑑 = 0
And
𝐷𝑥3 , 𝑑 = (1 − 0.99) ∗ 88739.85
𝐷𝑥3𝑑 = 887.3985 𝑘𝑔/ℎ𝑟
𝐷 = 𝐷𝑥1𝑑 + 𝐷𝑥2𝑑 + 𝐷𝑥3𝑑 + 𝐷𝑥4𝑑 + 𝐷𝑥5𝑑 + 𝐷𝑥6𝑑
𝐷 = 0 + 1850.585 + 887.3985 + 0 + 0 + 503.0412
𝐷 = 32041.025 𝑘𝑔/ℎ𝑟
For bottom section:

𝑊𝑥1𝑤 = 27589.21 𝑘𝑔/ℎ𝑟
𝑊𝑥6𝑤 = 0
𝑊𝑥4𝑤 = 324.1053 𝑘𝑔/ℎ𝑟
𝑊𝑥5𝑤 = 324.1053 𝑘𝑔/ℎ𝑟
𝑊𝑥2𝑤 = 1869.278 − 1850.585
𝑊𝑥2𝑤 = 18.692 𝑘𝑔/ℎ𝑟
16
𝑊𝑥3𝑤 = 88739.85 − 887.3985 = 87852.45 𝑘𝑔/ℎ𝑟
𝑊 = 𝑊𝑥1𝑤 + 𝑊𝑥2𝑤 + 𝑊𝑥3𝑤 + 𝑊𝑥4𝑤 + 𝑊𝑥5𝑤 + 𝑊𝑥6𝑤
𝑊 = 27589.21 + 18.692 + 87852.45 + 324.1053 + 324.1053 + 0
𝑘𝑔
𝑊 = 116108.6 ℎ𝑟
Table 4.7: DC-101 balance

p-xylene 27589.21 - 27589.21
Benzene 1869.278 1850.585 18.69278
Toluene 88739.85 887.3985 87852.45
Methanol - - -
Water - - -
m- xylene 324.1053 - 324.1053
o-xylene 324.1053 - 324.1053
Ethylene 503.0412 503.0412
Total 119349.6 3241.025 116108.6
119349.6 119349.6
Conditions
Assumptions
2. 99.5% toluene goes to top product and 99.5% of p-xylene goes to bottom
17

p-xylene 27589.21 137.946 27451.26
Benzene 18.69278 18.69278 -
Toluene 87852.45 87413.19 439.2623
Methanol - - -
Water - - -
m- xylene 324.1053 - 324.1053
o-xylene 324.1053 - 324.1053
Ethylene - - -
Total 116108.6 87569.83 28538.74
116108.6 116108.6
Conditions
Assumptions
2. 99% p-xylene goes to top product and 100% m-xylene goes to bottom with the
solvent.
18
Figure 4.7: Distillation DC-103
Table 4.9: DC-103 balance (3) (8)
A17(Feed) A20(Solvent) A21(Bottom) A22(Top)
p-xylene 27451.26 - 274.5126 27176.75
TBMX - - 324.1053
Toluene 439.2623 - 0 439.2623
Methanol - - - -
Solvent (DTBB) - 388.926 - -
DTBB - - 64.821 -
m- xylene 324.1053 - - -
o-xylene 324.1053 - 275.4895 48.61579
Benzene - - 0 324.1053
Total 28538.74 388.926 938.928 27988.73
28927.66 28927.66
Conditions
Assumptions
2. 99.5% toluene goes to top product and 99.5% of p-xylene goes to bottom
19
Figure 4.8: Distillation Column DC-104

p-xylene 27176.75 135.8837 27040.8675
Toluene 439.2623 437.065 2.19631128
o-xylene 48.61579 0 48.61579132
benzene 324.1053 324.155 0
Total 27988.73 897.05 27091.68
27988.73 27988.73
Final Product = (27040.87*24)/1000 =649 ton/day
4.6.Overall Plant Material Balance
4.7. Table 4.11: Overall plant material balance
Streams Inlet (kg/hr) Outlet (kg/hr)

A1 29875.48031 -
A2 14937.74016 -
A20 388.9263 -
A8 - 4265.289
A12 - 8767.976
A14 - 3241.025
A21 - 938.9285
A23 - 27091.6796
A24 - 897.0549766
Total 45202 45202
20
Chapter # 05
Energy Balance
5.1. Energy Balance across Reactor (R100)
5.1.1. Energy Balance Steps for Reactor
1. Select a Reference Temperature for energy balance i.e. 25 oC.
2. Calculate Cp values at average temperature of every component.
3. Estimate the standard heat of reaction @ 25 oC for every reaction.
4. Calculate the heat of reaction at given temperature for every reaction and calculate the
total heat of reaction.
5. Calculate the overall heat content at inlet and at outlet.
6. Apply the energy balance equation to calculate the heat duty.
7. By using this heat duty, calculate the mass flow rate of cooling water.
5.1.2. CP Value Calculations for Gases (7)
Table 5.1: Cp Value Calculations for Gases

Component A B C D
p-xylene -25.091 0.60416 -0.0003374 6.82E-08
Benzene -33.917 4.74E-01 -0.0003017 7.13E-08
Toluene -24.355 5.12E-01 -0.0002765 4.91E-08
Methanol 21.152 7.09E-02 2.59E-05 -2.852E-08
Water 32.243 1.92E-03 1.06E-05 -3.596E-09
m- xylene -29.165 6.30E-01 -0.0003747 8.48E-08
o-xylene -15.851 5.96E-01 -0.0003443 7.53E-08
Ethylene 3.806 1.57E-01 -0.00008348 1.76E-08
Cp = 𝐴 + 𝐵𝑇 + 𝐶𝑇 2 + 𝐷𝑇 3
21
Where T is in Kelvin and Cp in kJ/kmole.K
5.1.3. Reactions and Conversion (3)

Main Reaction
CH3OH (Methanol) + C7H8 (Toluene) C8H10 (p-X) + H2O
(23% overall conversion of Toluene from which 83% convert into p-X and 17%
loss to side reaction)
Side Reactions
1. 2 CH3OH C2H4 (Ethylene) + 2 H2O
(40% of Methanol fed is converted in this reaction)
2. C7H8 (Toluene) ½ C6H6 (Benzene) + ½ C8H10 (p-X)

(17% of 23% Toluene is converted in this reaction)
3. C8H10 (p-X) ½ C8H10 (o-Xylene) + ½ C8H10 (m-Xylene)

(2.53% of p-X is converted to o-X and m-X)
Table 5.2: Standard Heat of formation
Component ∆Hfo (kJ/kmol)
p-xylene 17.9
Benzene 82.8
Toluene 50.1
Methanol -201
Water -241.83
m- xylene 17.2
o-xylene 19.1
Ethylene -
5.1.4. Standard Heat of Reaction (13) (14)
∆Hrxno = ∑ vp . ∆Hfo (products) - ∑ vr . ∆Hfo (reactants)
Where vp = stoichiometric co-efficient of products
vr = stoichiometric co-efficient of reactants
22
For main reaction
∆Hrxno = -73 (kJ/kmol)
For side reactions
1. ∆Hrxno = - 11 (kJ/kmol)
2. ∆Hrxno = 0.13 (kJ/kmol)
3. ∆Hrxno = 0.25 (kJ/kmol)
5.1.5. Heat of Reaction
(15)
To evaluate the heat of reaction at temperature T2 knowing the heat of reaction at
temperature T1. This is found by the law of conservation of energy as follows:
In terms of enthalpies of reactants and products this becomes
Where subscripts 1 and 2 refer to quantities measured at temperatures T1 and T2, respectively.
Heat of Reaction @ 400 oC
For main reaction
∆Hrxn = - 19584227.8 (kJ/hr)
For side reactions
1. ∆Hrxn = - 747708.348 (kJ/hr)
2. ∆Hrxn = - 401.56 (kJ/hr)
3. ∆Hrxn = 5759.29 (kJ/hr)
23
Overall heat of reaction
∆Hrxn, 400 oC = - 20326578.42 (kJ/hr)
5.2. REACTOR (R100)
Reactor Conditions
Isothermal Conditions
Operating T = 400 oC
Figure 5.1: Reactor R-100
Operating P = 3 bar
Basis
Feed flow = 1900 kmol/hr or 136800 kg/hr (A5)
Table 5.3: Reactor Heat Calculations
Component Inlet(A5) Outlet(A6) Cp (avg. T) Qin Qout

(kmol/hr) (kmol/hr) (kJ/kmol.K) (kJ/hr) (kJ/hr)
p-xylene - 260.4523 197 - 19240914
Benzene - 24.76333 133 - 1235070
Toluene 1266.667 975.3333 165 78375206 60348729
Methanol 633.3333 138.1933 58.4 13869927 3026433
Water - 495.14 35.3 - 6554416
m- xylene - 3.058854 198 - 227119.6
o-xylene - 3.058854 201 - 230560.8
Ethylene - 126.6667 62.2 - 2954501
Total 1900 2026.667 - 92245133 93817743
5.2.1. Heat Duty
◦ Q = Heat In - Heat Out + ∆Hrxn, 400 oC
◦ Q = -21899188.82 kJ/hr = -6083.108 Kw
24
5.2.2. Mass Flow Rate of Water
𝑸 = 𝒏. 𝑪𝑷 (𝟕𝟎 − 𝟐𝟓)
Tavg = (25+70) / 2 = 47.5 oC
𝐶𝑃 = 75.238 kJ / kmol.K
𝑛. = 1.783 kmol/s
𝑚. 𝑤𝑎𝑡𝑒𝑟 = 32.1 kg/s
5.3. Energy Balance across Heat Exchanger (H-100)
5.3.1. CP Value calculations for liquids (16)
Table 5.4: Cp value calculations for liquids
Component C1 C2 C3 C4
Methanol (liq) 105800 -362.23 0.9379 -
𝐶𝑃𝐿 = 𝐶1 + 𝐶2 𝑇 + 𝐶3 𝑇 2 + 𝐶4 𝑇 3 + 𝐶4 𝑇 4
Where T is in Kelvin
Cp of methanol at 333K = 89.180 kJ/kmole.K
5.3.2. Cp Value calculations for gases (10)
Table 5.5: Cp value calculations for gases
Component A B C
Methanol (gas) 2.211 12.216*10-3 -3.45*10-6
𝑖𝑔
𝐶𝑃 /𝑅 = 𝐴 + 𝐵𝑇 + 𝐶𝑇 2 + 𝐷𝑇 −2
Where T is in Kelvin
Cp of methanol at 520.5K = 63.47 kJ/kmole.K
5.3.3. 𝝀 Calculations for methanol
TC = 512.64 K
25
𝑘J
𝜆 at 298K = 35.21 𝑚𝑜𝑙𝑒 (17)
Δ𝐻2 1−𝑇 0.38
= (1−𝑇𝑟2 ) (10)
Δ𝐻1 𝑟1
𝑘J 𝑘J
𝜆 at 368K = 30.3079 𝑚𝑜𝑙𝑒 = 30307.9 𝑘𝑚𝑜𝑙𝑒
TSTEAM=406.68K PSTEAM =3 bar

Boiling point of methanol at 3 bar=368K
𝑄 = 𝑚. 𝐶𝑃𝑙𝑖𝑞 (368 − 298) + 𝑚𝜆368𝑘 + 𝑚. 𝐶𝑃𝑔𝑎𝑠 (673 − 368)
𝑘𝑚𝑜𝑙𝑒
𝑚. = 466.8 ℎ𝑟
𝑄 = 7249.51𝑘𝑊
.
𝑄 = 𝑚steam Δ𝐻𝑣
𝑘𝐽
Δ𝐻𝑉@3𝑏𝑎𝑟 = 2724.667 𝑘𝑔
. 𝑘𝑔
𝑚𝑠𝑡𝑒𝑎𝑚 = 2.6607 𝑠
Similarly calculations are same for other heat exchangers as for H-100.
Table 5.6: Heat Duties calculations for heat exchanger
Heat Exchanger Heat Duty (kW)

H-100 7249.51
H-101 7734
H-102 -45297
H-103 20295
5.4. Energy Balance across Flash Vessel (V-100)
5.4.1. Energy balance steps for Flash vessel:
1. Select a reference Temperature for energy balance i.e 25 oC.
2. Calculate Cp values at average temperature of every component.
3. Calculate the overall heat content at inlet and at outlet.
4. Apply the energy balance equation to calculate the heat duty.
26
Inlet:
500 C
∆Hfeed = ∫250 C mCp(liq) (∆T)
Outlet:
50
Bottom ∆Hb = ∫25 mCpliq (∆T)
T
Top ∆HT = ∫T mCpgas ∆T
ref
5.4.2. Heat Removed (∆Hr):
∆Hr = outlet heat − inlet heat
∆Hremoved = −35.14kW
5.5. Energy Balance across Distillation Column (DC-100)
Components Involved
 Methanol
 Water
At Feed:
Table 5.7: DC-100 energy calculation data
Component Mass rate Mass Moles rate Mole T (K) T λ

s (kg/hr) fractio (Kmole/hr fractio Critica Reduced (kJ/mole)
n ) n l
Methanol 4372.55 0.3316 136.6423 0.2182 513 0.63 33.2
Water 8812.37 0.6684 489.5763 0.7818 647 0.5 40.65
Total Feed 13184.9 1 626.2186 1
3
P (total) = 4.00 = 3000mmHg
𝑃 𝑆𝐴𝑇
𝑘=𝑃
𝑇𝑂𝑇𝐴𝐿
27
𝐵
𝑙𝑛(𝑃𝑆𝐴𝑇 ) = 𝐴 + 𝐶+𝑇
Table 5.8: Data for bubble point calculation of DC-100
Components A B C
Methanol 16.61042 3392.57 230
Water 18.5882 3984.92 233.43
5.5.1. Bubble Point Calculation:
At T=148.248 0C
For Methanol
PSAT=2082.349mmHg
For Water
PSAT=3455.324mmHg
𝑃 𝑃
𝑘1 = 𝑃 1𝑆𝐴𝑇 𝑘2 = 𝑃 2𝑆𝐴𝑇
𝑇𝑂𝑇𝐴𝐿 𝑇𝑂𝑇𝐴𝐿
k1=0.692 k2 =1.1518
𝑦 = ∑ 𝑘𝑖𝑥𝑖
xF1=0.3316 xF2=0.6683
y=1
5.5.2. Dew Point Calculation
𝐲
𝐱𝐢 = ∑ 𝐤 𝐢
𝐢
AT 1510C
yF1=0.3316 yF2=0.6683
x=1
So, 148.2480C and 1510C are the boiling point and dew point simultaneously at feed point.
With the same process
28
At top
Bubble Point= 143.220C
At Bottom
Bubble Point= 163.30C
As the Temperature at the top of the Column is equal to the bubble point of the composition
at the top, so the temperature at the top is equal to 143.20C
As the temperature at the bottom is equal to the bubble point of the composition at bottom, so
the temperature at the bottom is equal to 163.30C.
5.5.3. Cp calculation
𝑪𝒑 = 𝑪𝟏 + 𝑪𝟐 𝑻 + 𝑪𝟑 𝑻𝟐 + 𝑪𝟒 𝑻𝟑 + 𝑪𝟓 𝑻𝟒
Table 5.9: Cp Calculation data for DC-100
Components C1 C2 C3 C4 C5
Toluene 140140 -152.3 0.695 0 0

Methanol 105800 -362.23 0.9379 0 0
Benzene 162940 -344.94 0.85562 0 0
Water 276370 -2090.1 8.125 -0.01412 9.3701E-06
p-xylene -35500 1287.2 -2.599 0.002426 0
o-xylene 36500 1017.5 -2.63 0.00302 0
m-xylene 133860 7.8754 0.52265 0 0
Ethylene 247390 -4428 40.936 -0.1697 0.00026816
At Feed T= 500C
Cp=77.12 kJ/kmole.K
At Top T=143.870C
Cp=83.489 kJ/kmole.K
At Bottom T=163.30C
29
Cp=75.28kJ/kmoleK
λ Calculation:
1−𝑇𝑅𝐸𝐷𝑈𝐶𝐸
λ= (1−𝑇 ) ∗ 𝜆STND
𝑅𝐸𝐷𝑈𝐶𝐸(𝑆𝑇𝑁𝐷)
𝑇
𝑇𝑟 = 𝑇
𝐶
For Methanol Tc=513K
For Water Tc=647K
At bubble point of distillate: (143.87 0C)
λtop=40.629 kJ/kmole
5.5.4. Enthalpies of the streams
Tref = 25 0C
Table 5.10: Streams of DC-100
Stream Toluene Methano p- m- o- Water Total

(moles) l xylen xylene xylene
e
A11 0 136.6423 0 0 0 489.5763 626.218
A12 0 1.36642 0 0 0 484.6805 486.047
A13 0 135.275 0 0 0 4.895763 140.171
At Feed:
Feed flow rate = 626.2186 kmoles/hr
∆𝐻𝑓 = 𝐹𝐶𝑝 (𝑇𝐹 − 𝑇𝑅𝐸𝐹 )
∆𝐻𝑓 = 1207756.68 kJ/hr
At bottom (W):
Bottom Flow rate = 486.047 kmoles/hr
TW=163.3 0C
30
∆𝐻𝑤 = 𝑊𝐶𝑝(𝑇𝑤 − 𝑇𝑟𝑒𝑓 )
∆𝐻𝑤 = 1391228.45 kJ/hr
At Distillate (D):
Distillate flow rate = 140.1716 kmoles/hr
TD=143.2 0C
∆𝐻𝐷 = 𝐷𝐶𝑝(𝑇𝑑 − 𝑇𝑟𝑒𝑓 )
∆𝐻𝐷 = 5060507.9kJ/hr
At Vapor V: Vapor flow rate =V= 1424.118 kmoles/hr
∆𝐻𝑉 = 𝑉𝐶𝑝(𝑇𝐷 − 𝑇𝑅𝐸𝐹 ) + 𝑉𝜆𝐵𝑈𝐵𝐵𝐿𝐸
∆𝐻𝑉 = 26234582.9kJ/kmole
At Reflux L:
Reflux flow rate =L= 938.0707 kmoles/hr
∆𝐻𝐿 = 𝐿𝐶𝑝(𝑇𝐿 − 𝑇𝑅𝐸𝐹 ) = 9258828.02 kJ/kmole
5.5.5. Condenser Duty:
Condenser duty is equal the amount of heat removed at the top of the distillation column
through condenser. This heat duty is equal to subtraction of heat of the distillate and the reflux
from the heat of vaporization of the top vapors.
𝑄𝐶 = ∆𝐻𝑉 − (∆𝐻𝐿 + ∆𝐻𝐷 )

𝑄𝑐 = 15533619kJ/hr = 4314.89 kW
5.5.6. Re-Boiler duty:
Re-Boiler duty is equal to the amount given at the bottom of the distillation column to reach
up to the bubble point of the bottom stream.
𝑄𝑏 = ∆𝐻𝐹 − (𝑄𝐶 + ∆𝐻𝐷 + ∆𝐻𝐵 )
𝑄𝑏 = −17995141𝑘𝐽/𝑘𝑚𝑜𝑙𝑒 = −4998.6 kW
Similarly calculations are same for other distillation columns as for DC-100.
31
Table 5.11: Duties of Distillation Column DC-100
Distillation Column Condenser Duty (kW) Reboiler Duty (kW)

DC-101 -319.59 4702.95
DC-102 -25.06 1071.48
DC-103 -8.6 147.35
DC-104 -7.96 117.19
32
Chapter # 06
Equipment Design
6.1. Reactor Design (R-100)
6.1.1 Design Steps for Reactor
1. Specify flow rates and operating conditions
2. Select suitable catalyst and particle size
3. Select a suitable reactor configuration
4. Calculate rate of reaction using experimental data
5. Calculate weight of catalyst using design equation for Packed Bed Reactor
6. Calculate volume of catalyst and volume of reactor
7. Calculate diameter and length of reactor using L/D Ratio
8. Calculate number of tubes and their dimensions
9. Calculate Reynolds number and calculate pressure drop
6.1.2. Selection of Reactor (18)
 Batch reactors are only used for small scale production and suitable for long time
reaction but it is not applicable in large scale production industrially.
 Continuous Stirred Tank Reactor (CSTR) is complex and expensive in comparison with
tubular reactor. CSTRs are used for slow liquid phase and slurry reactions and mostly
can’t be used for heterogeneous gas phase reactions.
For homogenous reactions

 Plug flow reactor
 Continuous stirred tank reactor
For heterogeneous reactions
 Packed bed reactor
 Fluidized bed reactor

33
Table 6.1: Selection of Distillation Column
Sr.# Reactor Advantages Disadvantages

Type
 Has the ability to process large  Effective temperature control
volumes of fluid of larger fixed beds is difficult
1. Packed bed  Low residence time which is  Pressure drop is high
reactor more feasible for exothermic  Offline regeneration
reactions
 Relatively easy maintenance
 Useful when solid particles  Have large residence time
which are involved in reactions distribution because of the
must be removed ease of backflow in the gas
2. Fluidized frequently.(online regeneration) and approach CSTR behavior
bed reactor  Temperature uniformity  It can’t be used for catalyst
 Excellent solid gas contact particle size greater than
 Ability to process fine particles 0.0001m
and suitability to high reaction
rate processes
 In this type, catalyst is filled in  Experience increased
tubes arranged in parallel with a complexity
heat conducting fluid flowing  Packing and removing the
Multi- outside the tubes catalyst from the tubes can be
3. tubular  Offer good thermal control and difficult.
packed bed uniform residence time  High pressure drop
reactor distribution
 Suitable for very exothermic
reactions
 High Performance due to
multiple beds
34
6.1.3. Reactor Configuration
(18)
Figure 6.1: Reactor Configuration
6.1.4. Catalyst Used (3)
Mg-Based modified ZSM-5 is used as a catalyst due to following reasons:
 High space velocity (equivalent to low space time) reduces the contact time at
the external surface and suppresses the xylene isomerization reaction over the
external surface.
 p-xylene selectivity approaches 100% as space time tends to zero over Mg

modified ZSM-5 catalyst; this is attributed to diffusional resistance to other
isomers. High p-xylene selectivity results in negligible production of unwanted
xylene isomers and significant reduction in the separation cost of p-xylene.
 The average size of particle is 0.0075m.
6.1.5. Reaction Kinetics and Experimental Data (3)
35
6.1.6. Reaction Kinetics and Design (15)
For First Reaction
R=8.314 kJ/kmol.K , T = 673.15K , P = 3 bar = 2.96 atm
45700 𝑘𝑚𝑜𝑙
k1 = 405 𝑒𝑥𝑝 (− ) = 0.115 𝑘𝑔.ℎ𝑟.𝑎𝑡𝑚2
𝑅𝑇
−𝑟𝐴 = k1 pM.pT = k1 (yTo.P(1-XA)) (yMo.P(1-XA))

Generate data b/w XA and −𝑟𝐴 upto XA = 0.254 and use Simpson’s 1/3rd rule for
numerical integration
= 1.52
Design Equation for PBR
FA0 = 1900 kmol/hr
Weight of catalyst = W1 = 2888 kg
Density of catalyst = 823 kg/m3
Volume of catalyst = V1 = 3.51 m3
For Second Reaction
k2 = 1346 𝑒𝑥𝑝 (− ) = 0.1594 𝑘𝑔.ℎ𝑟.𝑎𝑡𝑚2
𝑅𝑇
−𝑟𝐴 = k2 pM 2 = k2 (yMo.P(1-XA))2
= 0.4775

36
FA0 = 391.53 kmol/hr
Weight of catalyst = W2 = 186.955 kg
For Third Reaction:
k3 = 96.2 𝑒𝑥𝑝 (− ) = 0.00254 𝑘𝑔.ℎ𝑟.𝑎𝑡𝑚2
𝑅𝑇
−𝑟𝐴 = k3 pT = k2 (yTo.P(1-XA))
= 5.428
FA0 = 1024.87 kmol/hr
For Fourth Reaction
k4 = 46.94 𝑒𝑥𝑝 (− ) = 0.00753 𝑘𝑔.ℎ𝑟.𝑎𝑡𝑚2
𝑅𝑇
−𝑟𝐴 = k4 pp-X = k2 (yp-Xo.P(1-XA))

37
= 1.149
FA0 = 266.57 kmol/hr
Total Weight of Catalyst = W1 + W2 + W3 + W4 = 8904.102 kg
Total Volume of Catalyst = V1 + V2 + V3 + V4 = 9.537 m3
Void Fraction of Catalyst = 0.35
For Tube Side
9.537
Volume of Reactor Tubes = = 14.673m3
0.65
L/D Ratio = 4 (Range 3-5)
L = 4D
D = 1.6715 m
L = 6.6859 m
Contact time (19)
𝐴𝑐𝑡𝑖𝑣𝑒 𝐶𝑎𝑡𝑎𝑙𝑦𝑠𝑡 𝑉𝑜𝑙𝑢𝑚𝑒 (𝑚3) 9.537

Contact time = 𝑚3 = 25593.53 = 0.00037hr
𝑅𝑒𝑎𝑐𝑡𝑎𝑛𝑡 𝐹𝑒𝑒𝑑 𝑅𝑎𝑡𝑒 ( )
ℎ𝑟
Contact time = 1.34 sec
38
6.2. Mechanical Design of Reactor (18)
6.2.1. Materials of Construction
Since no corrosive chemicals are handled in this process, the construction materials are only
carbon steel. With temperatures greater than 454°C require the use of 304 SS. The maximum
allowable stress of carbon steel is 82700 kPa. Carbon steel is economical.
For Cylindrical Shell, Minimum Wall Thickness:
𝑃𝑟𝑖
𝑡 (𝑚) = + 𝐶𝑐
𝑆𝐸𝑗 −0.6𝑃
Where
𝐸𝑗 = 𝐽𝑜𝑖𝑛𝑡 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 = 0.85 (spot examined double welded butt-joint)
𝑆 = Max. Allowable Stress = 82700 kPa
Cc = Corrosion allowance (assume zero)
ri = radius of shell = 1.238 m
t = 0.00529 m = 5.29mm
6.2.2. Vessel Weight
Vessel weight= W =π(Di+tw)(L+0.8Di)twρ
Vessel weight= W = 344.99 lb
Weight of Tubes
Tube weight=2.41Lb/ft length
Weight of tube bundle =2.41*20*1535 = 73987 lb
6.2.3. Head Selection and Design
The ends of a cylindrical vessel are closed by heads of various shapes. The principal types used
are:
 Flat plates and formed flat heads

 Hemispherical head
39
 Ellipsoidal head
 Tori spherical head
Table 6.2: Selection of the Head
Flat head Tori spherical head Ellipsoidal head Hemispherical head

Applicable to low Used up to the Above 15 bars Used for very high
pressure operating pressure of ellipsoidal head is pressures
15 bar used
Cheapest from all Above 10 bars their Economical within Capital cost is high
types cost should be pressure limits
compared with that
of an equivalent
ellipsoidal head
So the right choice of head is Tori spherical head.
6.2.4. Shell and Tube Configuration of Reactor
OD of tube = 2 inch = 0.0508 m
Thickness of tube = 0.12 in = 0.00304 m
BWG= 11
Inner cross sectional flow area per tube= 2.433 inch2 = 0.00157 m2
Length of 1 tube = L = 20 ft = 6.09m
Volume of 1 tube = (0.00157)(6.09) = 0.00956 m3
𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑅𝑒𝑎𝑐𝑡𝑜𝑟 𝑓𝑜𝑟 𝑐𝑎𝑡𝑎𝑙𝑦𝑠𝑡

No of tubes = = (14.673)/(0.00956) = 1535
𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 1 𝑡𝑢𝑏𝑒
Triangular tube pitch = 1.25* OD = Pt = 2.5 inch = 0.0635m
Tube Clearance = 0.0635 – 0.0508 = 0.0127 m

1
b 𝑁 (𝑛1)
Dia of bundle = D = 𝑑𝑜 (𝑘1) (7)
do= outer dia of tube in mm
N= number of tubes
40
For triangular pitch and 1 pass
k1= 0.319
n1= 2.142
Db= 2367.75 mm = 2.367 m
Length of 1 Tube = 6.09 m
𝜋 𝐷𝑏2 𝑙
Volume of tube bundle = 4
Volume of tube bundle = 26.8 m3
Clearance = 127 mm
Inside dia of shell = Db + Clerance
Inside dia of shell = 2476.75 mm = 2.4767 m
Thickness of wall = 5.29 mm
Outside dia of shell = 2.4873 m
Length of shell= 4D = 9.95 m
𝜋 𝐷2 𝑙
Volume of shell = 4
Volume of shell = 48.35 m3
20 percent excess for shell
Volume of shell = 1.2* 48.35
Volume of shell = 58.02 m3
Dia of reactor shell = 2.64 m
Length of reactor shell = 10.57 m
6.2.5. Heat Transfer Area
Outside surface area per tube = 0.159m2/m * 6.09 = 0.973 m2/tube
Heat transfer area = 0.973*1535 = 1493.55 m2
41
Q= UA ∆Tlm
Cold fluid inlet temperature = 20o C
Cold fluid outlet temperature = 75o C
Hot fluid temperatur = 400o C
LMTD = (ΔT1 - ΔT2) / ln(ΔT1/ΔT2)
∆Tlm = 352.02 K
𝑊
Overall Heat Transfer Co-efficient = Q/ A ∆Tlm = 11.57 𝑚2.𝐾
𝑊
U = 11.57 𝑚2.𝐾
6.2.6. Pressure Drop Calculations (20)
∆𝑝 150∗𝜇∗(1−𝜀)2 ∗𝜇𝑜 1.75∗(1−𝜀)∗𝜌∗𝜇𝑜2

= 2 + 2
𝐿 𝜀 3 ∗(𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒 𝑑𝑖𝑎) 𝜀 3 ∗(𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒 𝑑𝑖𝑎)
𝜀 = 𝑣𝑜𝑖𝑑 𝐹𝑟𝑎𝑐𝑡𝑖𝑜𝑛=0.35
L= length of bed = 6.6859 m
𝜌 = 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓𝑔𝑎𝑠 = 5.3451 𝑘𝑔/𝑚3
𝜇 = 𝑣𝑖𝑠𝑐𝑜𝑠𝑖𝑡𝑦 = 0.00011355 𝑘𝑔/𝑚.s

𝑚
𝜇𝑜 = 𝑠𝑢𝑝𝑒𝑟 𝑓𝑖𝑐𝑖𝑎𝑙 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 = 2.95 𝑠𝑒𝑐
Particle Dia= 0.0075 m
∆𝑃 = 51342.38 Pa
∆𝑃 = 51.342 kPa
42
Table 6.3: Specification Sheet and design data for reactor (R-100)
Specification Sheet
Identification
Item Reactor
Item No R-100
Number required 1
Operation Continuous
Type Packed Bed Multi-Tubular

Reactor
Function: Production of 650 ton/day Para-Xylene from Methylation of Toluene.
Design Data
Operating Temperature 400 ⁰C
Operating Pressure 3 bar
Contact time 1.34 sec

Volume of Reactor Shell 58.02 m3
Diameter of reactor 2.64 m
Length of reactor 10.57 m
Heat duty -6083.108 kW
Mass flow rate of cooling water 32.1 kg/sec
Outside dia of tube 0.0508 m
Length of 1 tube 6.09 m
Volume of 1 tube 0.00956 m3
No of tubes 1535
Pressure Drop 51.342 kPa
43
6.3. Heat Exchanger Design (H-100)
6.3.1. Shell & Tube Heat Exchangers
Advantages
 Widely known and understood since it is the most common type less thermally
efficient than other types of heat transfer equipment.
 Most versatile in terms of types of service
 Widest range of allowable design pressures and temperatures
 Subject to flow induced vibration which can lead to equipment failure
Disadvantages
 Not well suited for temperature cross conditions (multiple units in series must be
used)
 Contains stagnant zones (dead zones) on the shell side which can lead to corrosion
problems
6.3.2. Design Procedure of Heat Exchanger (shell and tube) (21)
The main steps of design the heat exchanger are summarized as follows:
1. Obtain the required thermo physical properties of hot and cold fluids at average
temperature of streams
2. Perform energy balance and find out the heat duty (Q) of the exchanger.
3. Calculate the LMTD.
4. Assume overall heat transfer coefficient (Uo).
5. Calculate Provisional area and number of tubes.
6. Specify the shell and tube configuration.
7. Calculate hi and ho.
8. Calculate the overall heat transfer coefficient (U). If it is not equal to assumed value
then again assume Uo until it becomes equal to assumed value.
9. Calculate the pressure drop.
44
LMTD
LMTD = (ΔT1 - ΔT2) / ln (ΔT1/ΔT2)

(ΔT)1= 54 0C
(ΔT)2= 3000C
LMTD= 143.45ºC
Provisional Area
Assume value of overall heat transfer coefficient Uo =2240 W/m2 ºC

A = [Q/ (UoΔTlm)]
Q = 20295 KW Uo = 2240 W/m2 ºC LMTD = 143.45 ºC
A = 61m2
Number of Tubes
From Table 10 Heat Exchanger and Condenser tube data
BWG= 16
Outer diameter of tube= O.D=25.4mm
inner Diameter of tube=I.D= 22.098 mm
Length of tube= 2.4384 m
Surface area of one tube= pi * O.D * L
Surface Area of one tube= 3.14*2.4384 *25.4*10-3
Surface area of one tube=0.1946 m2
No of tubes=Nt= Provisional Area / Area of one tube
No of tubes =61m2 /0.1946 m2 = 314
Tube passes = 2
No of tubes per pass= 314/2= 157
Tube Sheet Layout
Bundle Diameter = Db = O.D (Nt/K) 1/n

For Triangular pitch and two passes = K=0.249 , n = 2.207
Bundle Diameter = Db = 645 mm
Use a split ring floating head type
Bundle diametrical Clearance= 65 mm
Shell Diameter = 645 + 65 = 710 mm
45
(Nearest standard pipe size is 736 mm)
Shell Side Heat Transfer Coefficient (ho)
Choose baffle Spacing LB == ¼(ID) = 184 mm

Triangular Pitch =Pt= 1.25 * outside diameter of tube= 31.75 mm
C=Pt – O.D= 31.75 – 25.4 = 6.35 mm
Cross flow Area of shell = As= ID*C*B/Pt =0.027 m2
Gs=m/As=25.47 / 0.027 = 943 Kg/ m2. Sec
Equivalent diameter= De = 18.288 mm
u= 1.3*10^-5 Kg/ m.sec
Re=De*Gs/µ =18.288 *10^-3 * 943/1.3*10^-5 =
896112
Pr = µCp/k= 0.1987 Jh= 700 K= 0.000129 KW/ m2 ºC
ho = K (Re) ^0.8 * (Pr)^0.3 /(De)
ho= 3040.75 W/m2 ºC
Tube Side Heat Transfer Coefficient (hi)
Tube flow Area At =Nt *at/n

Nt= 314 at= 383.22mm n=2
At= 314*383.22*10^-6 /2 = 0.1135 m2
Mass velocity =Gt=W/At
Gt=7.57 / 0.1135 =66.75 Kg/m2.sec
hi = hio=8512.584W/m2. ºC (its value is constant since steam is condensing)
Overall Heat Transfer Coefficient
1/ Uo= 1/ho+1/hod+do*ln(do/di)/(2*kw+(1/hi+1/hid)*do
1/Uo= 0.0004463
Uo= 2240 W/m2. ºC
We above assumed value of 2240 W/m2. ºC
6.3.3. Pressure Drop Calculation (21)
Shell Side Pressure Drop
ΔPs= [f8(N+1) Dsρv2/2de)]

Ds=736 mm de=18.288 mm Ρ= 755 Kg/m3
At Re=896112, f=2*10^-2 Gs=943 Kg/ m2. Sec
N+1=L/Lb=2.4383/0.00184= 13
46
V= Gs/ Ρ =943/755=1.25 m/sec
ΔPs= 7.16psi
Tube side pressure drop
ΔPt= [(8fL Ρvt2 )/ 2di

f= 2.98*10^-3
L= 2.4384 m
P=1000Kg/m3
Vt=Gt/P = 66.75/1000= 0.066 m/sec
di = 22.098 mm
ΔPt=0.83 psi
6.3.4. Specification Sheet

Table 6.4: Specification Sheet for Heat Exchanger
Overall Heat transfer coefficient( Uo) 2240 W/m2. ºC
Heat transfer Area of heat exchanger (A) 61 m2
Total no. of tubes (Nt) 314

Diameter of shell (Ds) 0.736 m
Total pressure Drop (shell side) 7.16 psi
Total pressure Drop (tube side) 0.83 psi
No. of baffles 12
No of crosses 13
Bundle Diameter 645 mm
47
6.4. Design of Distillation Column (DC-100)
6.4.1. Selection of Column and Trays (18)
Factors which effect the selection of Column
In the selection of a distillation column the amount of liquid and vapors have a great importance
due to which different types of columns are used. There are some factors which depend upon
the selection of a column and have a great impact on the cost of the equipment with respect to
the
1. Pressure
2. Liquid to vapor density ratio
3. Liquid loading
4. Most important the fixed cost of the column.
6.4.2. Selection of the plate:
There are three main types of trays which are used for the distillation column.
1. Sieve tray
2. Valve tray
3. Bubble cap tray
The rules of thumb for selecting plate are
1. The compounds have relatively larger volatility
2. Pressure drop is low
3. Liquid loads are high
4. Mostly towers are of large diameter.(greater than 0.6m)
48
Table 6.5: Tray Selection of Tray in Distillation Column
Parameter Sieve Tray Valve Tray Bubble Cap Tray

Cost Low 1.5 times Sieve 3 times Sieve tray
tray
Operating Range 50% or greater of Greater flexibility Operate Efficiently
Design Capacity Than sieve 25- at very low rate 10%
30%
Efficiency High High Moderate High
Pressure Drop Lowest Greater than Sieve Highest
Plate
Maintenance Low Moderate Relatively high
Fouling Tendency Low Moderate High Tends to collect
solids
6.4.3. Some Important ways to select Tray of distillation Column:
1. In sieve tray liquid cannot be retained with a large amount and less use with the larger
liquid hold up.
2. By cost the price of bubble cap is very high and the pressure drop is also high and also
the maintenance cost is high.
3. Valve type tray is best to retain the solids and have lesser cost than the bubble cap and
also relatively less maintenance so the valve type tray is the best selection in the
following.
q-value calculation
𝐻𝑉 −𝐻𝐹
𝑞= 𝐻𝑉 −𝐻𝐿
26234582.9 − 1207756.68
𝑞=
26234582.9 − 9258828.02
𝑞 = 1.4787
𝑞
tanƟ = 𝑠𝑙𝑜𝑝𝑒 = 𝑞−1
Ɵ = 72.070
49
For Top line of feed
1
𝑦′ = (𝑅+1) 𝑋𝐷
𝑦′ = 0.33
6.4.4. Number of plate Calculation by McCabe and Thiele (11)
McCabe and Thiele method is used to calculate the number stages for the binary distillation
column. In this method number of stages are drawn in between the equilibrium line and the top
and bottom lines.
To draw a top line first we need the q-line.
q-line is different for the different conditions of the feed.
1. For super saturated stream q<0

2. For saturated vapor streams q=0
3. For liquid and vapor mixture 0<q<1
4. For saturated liquid stream q=1
5. For sub cooled stream q>1
Fig 6.2: q-line for different feed conditions
Super saturated stream is mainly not used in the distillation column because all the vapors move
with the upper stream in the distillation column. Mainly sub cooled and saturated liquid stream
is used in the distillation column.
50
6.4.5. Calculation by McCabe and Thiele:
Figure 6.3: Calculation by McCabe and Thiele
There are different symbols
 xd shows the fraction of methanol at the distillate

 xf is the fraction of methanol at feed point
 xw shows the fraction of methanol in the bottom stream
 The line joining the xf point with the top and bottom operating line is known as the q-
line
 The line joining the xd and y’ point is known as the top operating line
 The line joining the xw and top operating line is known as the bottom operating line.
These three line meet at one point.
6.4.6. Reflux calculation:
𝑅𝑀𝐼𝑁 = (𝑥𝑑 − 𝑦′)/(𝑦′ − 𝑥′)
𝑅𝑀𝐼𝑁 = 1.48999
𝑅 = 1.3 ∗ 𝑅𝑀𝐼𝑁
Range for R= (1-1.5)
𝑅 = 1.93699
51
As the reflux is 1.2- 1.3 times of the Rmin. So, I took it as 1.3 times of minimum reflux.
6.4.7. Densities for liquid and water
For liquids:
1. Feed stream ᵨ=944.168 kg/m3
2. Distillate stream ᵨ=666.945 kg/m3
3. Bottom stream ᵨ=996.02 kg/m3

For gases:
1. Feed stream ᵨ=3.136 kg/m3
2. Distillate stream ᵨ=3.637 kg/m3
3. Bottom stream ᵨ=1.989 kg/m3
Flow rates
Flow rates of different points in the distillation column are different which depend upon the
condition of the feed stream. As the stream in this distillation column is subcooled, so the flow
rates are depended on the q line of the feed stream.
𝐿𝑛
𝑅= 𝐷
𝐿𝑛 = 𝑅𝐷
𝑉𝑛 = 𝐿𝑛 + 𝐷
𝐿𝑚 = 𝐿𝑛 + 𝑞𝐹
𝑉𝑚 = 𝑉𝑛 + (1 − 𝑞)𝐹
FLV calculation:
1
𝐿𝑚 ᵨgas 2
FLV= (𝑉𝑚) ( ᵨ )
liq
For bottom For top
FLV=0.482 FLV=0.0486
(NOTE: Tray spacing (range 0.1-1m))

52
Let tray spacing is 0.3 m
From graph of FLV and tray spacing:
At bottom At top
K1=0.36 K1=0.041
Vapor flooding velocity:
(𝜌𝑙 − 𝜌𝑔 )/𝜌𝑔
𝑢𝑓 = 𝐾_𝑖√
𝑢𝑓 =8.0476 m/s
𝑢𝑓 =0.5537
Let 𝜀 = 80%
Operating Velocity:
At top At bottom
𝑢𝑛 = 𝑢𝑓 ∗ 0.8 𝑢𝑛 = 𝑢𝑓 ∗ 0.8
𝑢𝑛 = 6.437𝑚/𝑠 𝑢𝑛 = 0.443𝑚/𝑠
Flow Rates:
D = 1.227 kg/sec
F = 3.66 kg/sec
W = 2.436 kg/sec
Ln = 2.368 kg/sec
Lm = 5.996 kg/sec
Vm = 0.556 kg/sec
Vn = 3.595 kg/sec
53
Net area:
At Bottom
At Top
𝑉𝑛
𝑉𝑛 𝜌𝑏𝑜𝑡𝑡𝑜𝑚
𝜌𝑏𝑜𝑡𝑡𝑜𝑚 𝐴𝑛 =
𝐴𝑛 = 𝑢(𝑛)
𝑢(𝑛)
An=0.6308 m2
An=0.1535 m2
Area of Down Comer:
Area of Down Comer:
Ad=0.12*An
Ad=0.12*An
Cross-sectional area (Top) Cross-sectional area (Bottom)

Ac=An+Ad
Ac=An+Ad
Ac=0.17196 m2
2
Ac=0.17196 m
Diameter (Top) Diameter (Bottom)
𝜋𝑑2 𝜋𝑑 2
𝐴𝑐 = 𝐴𝑐 =
4 4
d=0.468 m d=0.948 m
Total Height of Column:
h= (N-1)*s*1.15
h=3.105m
h/d=3.273
Accurate Calculation:
Ac=Acbottom + 0.15Actop
Ac=0.7323
Area of Down Comer:
Ad=Adbottom+0.15Adtop
54
Active area:
Ap=Ac-2(Ad)
From graph
Lw/Dc=0.78
Lw=Wear Length
Lw=0.78*d(column)
Lw=0.74m
Hole Area (Ah):
𝐴ℎ = 0.035 ∗ 𝐴𝑝
Weir Height(hw) = 50mm (range up to 100mm)
plate thickness = 5mm
Hole diameter = 5mm
HOW:
𝑙𝑚
Mmax= 2 = 55.11 mm
(𝜌𝑏𝑜𝑡𝑡𝑜𝑚 ∗𝐿𝑤 )3
0.75𝑙𝑚
Mmin= 2 = 41.333 mm
(𝜌𝑏𝑜𝑡𝑡𝑜𝑚 ∗𝐿𝑤 )3
Hw+HOW(MIN)= 50 + 91.33 = 141.33m
From graph
K2=30.9
Minimum Design Vapor Velocity:
𝐾2 −(0.9(25.4−ℎ𝑜𝑙𝑒𝑑𝑖𝑎 ))
𝑢𝑚𝑖𝑛 = 𝜌𝑔(𝑏𝑜𝑡𝑡𝑜𝑚)
𝑚
𝑢𝑚𝑖𝑛 = 8.89 𝑠
Actual velocity:
0.7
𝜌𝑔(𝑏𝑜𝑡𝑡𝑜𝑚)
𝑢𝑎𝑐𝑡𝑢𝑎𝑙 = 𝑉𝑚 ( 𝐴ℎ
)
55
𝑚
𝑢𝑎𝑐𝑡𝑢𝑎𝑙 = 9.713 𝑠
𝑝𝑡
=1
ℎ𝑑
(𝐴ℎ /𝐴𝑝 ) ∗ 100 = 3.5
From Graph
Co=0.79
6.4.8. Plate pressure drop:
𝑢(ℎ) 2 𝜌𝑔(𝑏𝑜𝑡𝑡𝑜𝑚)
∆𝑑 = ( ) (𝜌 )
𝐶0 𝑙(𝑏𝑜𝑡𝑡𝑜𝑚)
∆𝑑 = 15.397𝑚𝑚(𝑙𝑖𝑞𝑢𝑖𝑑)
Residual Head:
103
ℎ𝑟 = 12.5 (𝜌 )
𝑙𝑖𝑞(𝑏𝑜𝑡𝑡𝑜𝑚)
ℎ𝑟 = 12.55 𝑚𝑚(𝑙𝑖𝑞𝑢𝑖𝑑)
Total Drop:
∆𝑃 = ℎ𝑜𝑑 + ℎ𝑤 + ℎ𝑟 + 𝐻𝑜𝑤𝑚𝑖𝑛
∆𝑃 = 108.8𝑚𝑚(𝑙𝑖𝑞𝑢𝑖𝑑)
Area of one hole:
𝜋
𝐴1𝐻𝑂𝐿𝐸 = (3.14) (ℎ𝑜𝑑 )2
Number of holes per plate:
𝐴
𝑁0 = (𝐴1ℎ )
ℎ
𝑁0 = 1027
56
Flooding velocity:
𝑉𝑀
𝜌𝑔(𝑏𝑜𝑡𝑡𝑜𝑚)
𝑢𝑛 = 𝐴𝑛
𝑚
𝑢𝑛 = 0.443 𝑠
Flooding Check:
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦𝑎𝑠𝑠𝑢𝑚𝑒𝑑
𝐹% = (𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 )
𝐶𝑎𝑙𝑐𝑢𝑙𝑎𝑡𝑒𝑑
𝐹% = 79.2%
As we supposed the flooding velocity in the start as 80% which is equal to this velocity so,
our design is accurate according to calculations.
6.4.9. Plate efficiency by (O’ Connell correlation):
𝑣𝑖𝑠𝑐𝑜𝑠𝑖𝑡𝑦𝑎𝑣𝑔 = 0.246𝑐𝑝 at average temperature of top and bottom
𝜖 = 51 − 32.5 log(𝛼𝑎𝑣𝑔 ∗ 𝑣𝑖𝑠𝑐𝑜𝑠𝑖𝑡𝑦𝑎𝑣𝑔 )
ᾳ (avg) = 0.600243
ἠ (avg)= 0.245751
ἠ (avg)= 78.01326 %
57
6.4.10. Specification Sheet for Distillation Column (DC-100)
Table 6.6: Specification sheet for distillation column DC-100

Item no. Equipment Name Operation Type
DC-100 Distillation Column Continuous Sieve Tray Type
Function Separation of Methanol and Water
Material Feed Top Bottom

Handled
Quantity 13184.93 4416.952 8767.976
kg/hr kg/hr kg/hr
Composition of 33.16% 98.0049% 0.4987%
VAM
Temperature 50 °C 143.3 °C 163.2 °C
Pressure 8 bar 1.1 bar 1.3 bar
Design Data
Number of Trays 10 Condenser Duty 4.291 MW
Feed Plate 7 Reboiler Duty 4.986 MW

located
Reflux Ratio 1.93 Flooding Velocity 0.7201 m/sec
Tray Spacing 0.31 m Tray Efficiency 78.2%
Diameter 0.951 m Column Efficiency 80%
Height 3.105 m Flow Arrangement Cross flow single pass
Pressure Drop 108.2 mmHg
58
6.5. Design of Flash Column (V-100)
6.5.1. Design Steps
 Select Kv
 Calculate the maximum vapor velocity , Vmax
 Calculate the Cross-Sectional area, A
 Calculate the Diameter from the equation, D
 Calculate the Volume of the column, V
 Calculate the Vapor level height, Hv
 Calculate the Liquid height, HL
 Calculate the total separator length, L
 Calculate L/D, If L/D is less than 5 then it will be Vertical Column
6.5.2. Design Calculations (22) (23)
Pressure
P=73.3 KPa
Liquid Phase Density
ƿL = 763.189Kg/m3
Vapor Phase Density
ƿv = 1.194 Kg/m3
Mass Flow rate of Liquid Stream
mL = 36.815 Kg/sec
Mass Flow rate of Vapor Stream
mv = 1.1848 Kg/sec
Vapor Velocity (Vv)
59
Vv = KV [(ƿL - ƿv)/ ƿv] 0.5
Vv = 0.0107 [(763.189-1.194)1.194] 0.5
Vv = 0.270 m/s
Where, velocity factor, Kv = 0.0107 m/s
6.5.3. Area (A):
Volumetric flowrate of Vapor stream = Qv = 0.99 m3/s
Area = Volumetric Flow rate / vapor velocity
A=Qv / Vv
A=0.99/0.270
A=3.66 m2
6.5.4. Diameter (D):
4𝐴
D=( 𝜋 )0.5
4 ×3.66 0.5
D= ( )
3.14
D=2.16 m
6.5.5. Volume (V):
Volumetric flow rate of Liquid stream
QL = 0.048 m3/sec
Volume = QL × t
V = 0.048 × 300
V = 14.4 m3
While t is the retention time in second
Liquid Height (HL)
60
HL=Volume holds up/Area =14.4/3.66 = 3.93 m
Vapor Height (Hv)
Hv=1.5 × D +0.45
HV=1.5 × 2.16+ 0.45
Hv =3.69 m
6.5.6.Total Length (L):
L= HL+HV
L= 3.93+3.69 = 7.62
Length to Diameter ratio (L/D)
L/D =7.62/2.16 = 3.53
As in this case L/D ratio lies between 3 and 5, therefore it also proves that it will be a Vertical
Separator.
6.5.7. Specification Sheet
Table 6.7: Specification Sheet for vertical flash separator
Unit Name Vertical Flash Separator
Equipment Code V-101
Vessel Area 3.66 m2
Vessel Diameter 2.16 m
Vapor Height 3.69 m
Liquid Height 3.93 m
Total Length 7.62 m
L/D ratio 3.53
61
Chapter # 07
Cost Estimation
7.1. Cost Estimation of Reactor
Vessel weight= W =π(Di+tw)(L+0.8Di)twρ
Vessel weight= W = 344.99 lb
Purchase cost($)
Cv=Fm exp(6.775+0.18255(lnW)+0.0229(ln(W^2)
Fm= adjustment factor=1
Cv=$2935.05
Added cost=Cpl=285.1.D0.7396L0.70684
Added cost=Cpl=$1833.9
Total purchase cost=Cp=(500/394)(Cv+Cpl)
Total purchase cost=Cp=$6051.97
Bare module cost=4.16*6051.97
Bare module cost=$25176.19
Tube weight=2.41Lb/ft length
Weight of tube=2.41*20*1535 = 73987 lb
Purchase cost($)=
Cv=Fm exp(6.775+0.18255(lnW)+0.0229(ln(W^2)
Purchase cost of tubes = $11466.27
Total cost = 6051.97 + 11466.27
Total cost=$36643.17
Cost of Catalyst = $400-500/ton
62
Total Cost of Catalyst = 450*8.904 = $4006.85
7.2. Cost of distillation Column:
7.2.1. DC-100
𝐶𝑜𝑠𝑡($) = 𝑎 + 𝑏(ℎ)𝑛
𝑎 = 130
𝑏 = 440
𝑛 = 1.8
ℎ = ℎ𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑐𝑜𝑙𝑢𝑚 𝑖𝑛 𝑚
ℎ = 3.105 𝑚
𝐶𝑜𝑠𝑡($) = 3511.9218
By the same procedure cost for the other distillation columns is
7.2.2. DC-101
𝐶𝑜𝑠𝑡 𝑓𝑜𝑟 𝐷𝐶 − 101($) =4766.77
7.2.3. DC-102
𝐶𝑜𝑠𝑡 𝑓𝑜𝑟 𝐷𝐶 − 102($) =8685.76
7.2.4. DC-103
𝐶𝑜𝑠𝑡 𝑓𝑜𝑟 𝐷𝐶 − 103($) =5955.09
7.2.5. DC-104
𝐶𝑜𝑠𝑡 𝑓𝑜𝑟 𝐷𝐶 − 104($) =3945.06
7.3. Cost of Flash Column
Cost of the Flash column is calculated with the same procedure as we calculated for
the distillation
7.3.1. V-100
𝐶𝑜𝑠𝑡 𝑓𝑜𝑟 𝑉 − 100($) =63285.46888

63
7.4. Cost of Heat Exchanger
7.4.1. H-100
𝐶𝑜𝑠𝑡($) = 𝑎 + 𝑏(𝐴)𝑛
𝑎 = 32000
𝑏 = 70
𝑛 = 1.2
𝐴 = 𝐻𝑒𝑎𝑡 𝑡𝑟𝑎𝑛𝑠𝑓𝑒𝑟 𝑎𝑟𝑒𝑎 𝑖𝑛 𝑚2
𝐴 = 115.519 𝑚2
𝐶𝑜𝑠𝑡($) = 52906.5
The cost of the other Heat Exchangers is also calculated with the same procedure as
done for this heat exchanger
7.4.2. H-101
𝐶𝑜𝑠𝑡 𝑓𝑜𝑟 𝐻 − 101($) =54387.71597
7.4.3. H-102
𝐶𝑜𝑠𝑡 𝑓𝑜𝑟 𝐻 − 101($) =302295.8414
7.4.4. H-103
𝐶𝑜𝑠𝑡 𝑓𝑜𝑟 𝐻 − 101($) =303065.6014
7.5. Cost of Mixer
7.5.1. M-100
𝐶𝑜𝑠𝑡($) = 𝑎 + 𝑏(𝐹)𝑛
𝑎 = 570
𝑏 = 1170
𝑛 = 0.4
𝑙𝑖𝑡𝑟𝑒
𝐹 = 𝐹𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 𝑖𝑛 𝑠𝑒𝑐
𝐹 = 0.0458 𝑠𝑒𝑐
64
𝐶𝑜𝑠𝑡($) = 910.857
7.5.2. M-101
𝑎 = 570
𝑏 = 1170
𝑛 = 0.4
𝐹 = 𝐹𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 𝑖𝑛 𝑠𝑒𝑐
𝐹 = 0.0308 𝑠𝑒𝑐
𝐶𝑜𝑠𝑡($) = 860.807
7.6. Cost of Decanter
7.6.1. D-100
𝑎 = 2800
𝑏 = 54
𝑛 = 01.2
𝐶𝑜𝑠𝑡 𝑜𝑓 𝑑𝑒𝑐𝑎𝑛𝑡𝑒𝑟 ($) =36643.5
7.7. Total Cost of the Plant
𝑇𝑜𝑡𝑎𝑙 𝐶𝑜𝑠𝑡 𝑜𝑓 𝑝𝑙𝑎𝑛𝑡 ($) = 𝑐𝑜𝑠𝑡 𝑜𝑓 𝑝𝑢𝑚𝑝𝑠 + 𝑐𝑜𝑠𝑡 𝑜𝑓 ℎ𝑒𝑎𝑡 𝑒𝑥𝑐ℎ𝑎𝑛𝑔𝑒𝑟𝑠 +

𝑐𝑜𝑠𝑡 𝑜𝑓 𝑟𝑒𝑎𝑐𝑡𝑜𝑟𝑠 + 𝑐𝑜𝑠𝑡 𝑜𝑓 𝑓𝑙𝑎𝑠ℎ 𝑐𝑜𝑙𝑢𝑚𝑛 + 𝑐𝑜𝑠𝑡 𝑜𝑓 𝑑𝑖𝑠𝑡𝑖𝑙𝑙𝑎𝑡𝑖𝑜𝑛 𝑐𝑜𝑙𝑢𝑚𝑛𝑠 +
𝑐𝑜𝑠𝑡 𝑜𝑓 𝑑𝑒𝑐𝑎𝑛𝑡𝑜𝑟
𝑇𝑜𝑡𝑎𝑙 𝐶𝑜𝑠 𝑜𝑓 𝑃𝑙𝑎𝑛𝑡 ($) = 579574.26
7.7.1. Direct Cost
Fixed Capital Investment

𝐸𝑞𝑢𝑖𝑝𝑚𝑒𝑛𝑡 𝐶𝑜𝑠𝑡 = 20% 𝑜𝑓 𝐹𝐶𝐼
𝐸𝑞𝑢𝑖𝑝𝑚𝑒𝑛𝑡 𝑐𝑜𝑠𝑡
𝐹𝐶𝐼 = 0.22
𝐹𝐶𝐼 ($) =3474031.086

65
Installation 8.3% of FCI
𝐼𝑛𝑠𝑡𝑎𝑙𝑙𝑎𝑡𝑖𝑜𝑛 𝑐𝑜𝑠𝑡 ($) = 288344.5801
Service Facilities 13.5% of FCI

𝑆𝑒𝑟𝑣𝑖𝑐𝑒 𝑓𝑎𝑐𝑖𝑙𝑖𝑡𝑖𝑒𝑠 𝑐𝑜𝑠𝑡 ($) = 468994.1965
Piping & Instrumentation 15% of FCI

𝑃𝑖𝑝𝑖𝑛𝑔 𝑎𝑛𝑑 𝑖𝑛𝑠𝑡𝑟𝑢𝑚𝑒𝑛𝑡𝑎𝑡𝑖𝑜𝑛 𝑐𝑜𝑠𝑡 ($) = 521104.6628
Electrical system 5% of FCI

𝐸𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑎𝑙 𝑠𝑦𝑠𝑡𝑒𝑚 𝑐𝑜𝑠𝑡 ($) = 173701.5543
Buildings 4% of FCI
𝑏𝑢𝑖𝑙𝑑𝑖𝑛𝑔 𝑐𝑜𝑠𝑡 ($) = 138961.2434
Land 1.5 % of FCI

𝐿𝑎𝑛𝑑 𝑐𝑜𝑠𝑡 ($) = 52110.46628
Yard Improvements 2%of FCI

𝑦𝑎𝑟𝑑 𝑖𝑚𝑝𝑟𝑜𝑣𝑒𝑚𝑒𝑛𝑡 𝑐𝑜𝑠𝑡 ($) = 69480.62171
7.7.2. Indirect Cost
Engineering and supervision 7.3% of FCI

𝐸𝑛𝑔𝑖𝑛𝑒𝑒𝑟𝑛𝑔 𝑎𝑛𝑑 𝑠𝑒𝑟𝑖𝑐𝑒𝑠 𝑐𝑜𝑠𝑡 ($) = 253604.2692
Legal expenses 1.8% of FCI

𝑙𝑒𝑔𝑎𝑙 𝑒𝑥𝑝𝑒𝑛𝑐𝑒𝑠 𝑐𝑜𝑠𝑡 ($) =62532.55954
Contractors fee 1.8% of FCI

𝐶𝑜𝑛𝑡𝑟𝑎𝑐𝑡𝑜𝑟𝑠 𝑓𝑒𝑒 𝑐𝑜𝑠𝑡 ($) =62532.55954
66
Contingency 7.3 % of FCI
𝐶𝑜𝑛𝑡𝑖𝑛𝑔𝑒𝑛𝑐𝑦 𝑐𝑜𝑠𝑡 ($) =253604.2692
Construction Expenses 9% FCI

𝐶𝑜𝑛𝑠𝑡𝑟𝑢𝑐𝑡𝑖𝑜𝑛 𝑐𝑜𝑠𝑡 ($) = 312662.7977
WCI = 15% OF FCI

𝑊𝐶𝐼 = 521104.6628
TCI = FCI+WCI
𝑇𝐶𝐼 = 3995135.748
SV = estimated salvage value (0.03 FCI)

𝑆𝑎𝑙𝑣𝑎𝑔𝑒 𝑣𝑎𝑙𝑢𝑒 ($) =104220.9326
Taxes1% of FCI
𝑇𝑎𝑥𝑒𝑠 ($) =34740.31086
Insurance 0.4% of FCI

𝐼𝑛𝑠𝑢𝑟𝑎𝑛𝑐𝑒 ($) = 13896.12434
Total fixed charges

𝑇𝐹𝐶 ($) =217126.9428
Maintenance Cost (2% of FCI)

𝑀𝑎𝑖𝑛𝑡𝑒𝑛𝑎𝑛𝑐𝑒 𝑐𝑜𝑠𝑡 ($) = 69480.62171
Operating labor 3% of FCI

𝑂𝑝𝑒𝑟𝑎𝑡𝑖𝑛𝑔 𝑙𝑎𝑏𝑜𝑢𝑟 𝑐𝑜𝑠𝑡 ($) = 104220.9326
67
POC = 60% of operating labor, maintenance cost & Supervision
𝑃𝑂𝐶 ($) = 256383.4941
Steam flow cost of steam

𝑆𝑡𝑒𝑎𝑚 𝑓𝑙𝑜𝑤 𝑐𝑜𝑠𝑡($) = 67468.25826
Operating Supplies (10% of Maintenance Cost)

𝑂𝑝𝑒𝑟𝑎𝑡𝑖𝑛𝑔 𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑠 𝑐𝑜𝑠𝑡 ($) = 6948.062171
Management Personnel (10 % of Operating Labor)

𝑀𝑎𝑛𝑎𝑔𝑒𝑚𝑒𝑛𝑡 𝑝𝑒𝑟𝑠𝑜𝑛𝑛𝑒𝑙 𝑐𝑜𝑠𝑡 ($) = 10422.09326
Laboratory Charges (5% Of Operating Labor)

𝐿𝑎𝑏𝑜𝑟𝑎𝑡𝑜𝑟𝑦 𝑐ℎ𝑎𝑟𝑔𝑒𝑠 ($) = 347.4031086
68
Chapter # 08
Process Simulation
8.1. Introduction to Process Simulation and Aspen HYSYS
Process Simulation is a key activity in Process Engineering covering the whole life cycle
of a process, from Research & Development to Conceptual Design and Plant Operation.
HYSYS is a powerful simulation tool that has been designed to solve complex engineering
problems along with the steady state and dynamic modeling capabilities and represent a
significant progression in the engineering software industry. The numerous components of
Aspen HYSYS provide a powerful approach to steady state modeling, mass and energy
balances, equipment design, optimization and cost estimation etc.
8.2. Simulation Procedure
 First open the Aspen HYSYS and opened the new window.
 Then added the components in the components section.
 Toluene
 Methanol
 Water
 P-Xylene
 m-Xylene
 o-Xylene
 ethylene
 benzene
 Then added the fluid package in the fluid package section
o Peng Robinson
 Then added the reaction in the reaction type section and add reaction kinetics.
 Then moved towards the simulation environment.
 Add a PFR to the simulation main tab.
 Then added the Heat Exchanger H-100 and named the steams which are added and
removed from it.
69
 Then added the parameters and conditions in the heat exchanger H-100 and calculated
the results from it.
 Repeat the same procedure for the heat exchanger H-101 and calculated the results
obtained from it.
 Then add the mixer and put the conditions for it and obtained the results from it.
 Then add the reactor and named the streams and put the conditions and conversion for
the reactions.
 Then obtained the results from it according to the composition and the conditions at the
outlet.
 Then add the flash column and calculated the results from it.
 Then add the decanter and calculated the results for it and the output results for it.
8.3. Simulation Results
8.3.1. For Pumps
70
Figure 8.1: Simulation Results For Pumps
8.3.2. For Heaters
71
Figure 8.2: Simulation Results For Heater
8.3.3. For Mixer
Figure 8.3: 1Simulation Results for Mixer
72
8.3.4. Plug Flow Reactor
Figure 8.4: Simulation Results For Plug Flow Reactor

73
1.3.5. Cooler
Figure 8.5: Simulation Results For Cooler
8.3.6. Flash Column
Figure 8.6: Simulation results for Flash Column:
74
8.3.7. Three Phase Separator
Figure 8.7: Simulation results for 3-Phase separator
75
8.3.8. Process Flow Diagram
Figure 8.8: Process Flow Diagram

8.3.9. Conversion Reactor (To validate material balance)
Figure 8.9: For Conversion Reactor (To validate material balance)
76
 These Compositions are same as calculated manually so it validate the material
balance across reactor used.
8.3.10. Conversion Reactor (To validate material balance)
Figure 8.10: For Conversion Reactor (To validate material balance)
77
Chapter # 09
HAZOP Study
(18)
9.1.HAZOP Study for Distillation Column (DC-100)
Table 9.1: Hazop Study for distillation column DC-100
Study Process Deviation Possible Possible Action required

Stream parameter (guide causes consequences
word)
Stream Flow NO Breakage of Feed loss Schedule

No. 11 pipe openly inspection.
Level will
decrease in
column (D-
100).
Stream Flow LOW Leakage or Decrease in Use check valves.
No. 11 purging of level in
something in column
pipes (D-100)
Stream Flow HIGH High Flooding in
No. 11 pressure Column (D-
from pump 100)
Distillation Level HIGH Input valve Over-pressure Use high

column leveller of reflux accuracy alarm
(D-100) damages drum. Inspect daily
Output valve Condensed
blockages liquid back
flow to
distillation
Distillation Level LOW Pipe partial Level Scheduling
column clogged or decrease in inspection.
(D-100) leakage. the vessel. Install valve.
Valve closed.
Backflow of
material.
Distillation Temperature HIGH Decrease in Off Install
column pressure of specification temperature
(D-100) boiler product. sensors.
78
Study Process Deviation Possible Possible Action required
Stream parameter (guide causes consequences
word)
Distillation Temperature LOW Increase in Decrease in Scheduling

column flow from level of boiler inspection.
(D-100) the Off Install
condenser specification temperature
product. sensors
Distillation Pressure HIGH Water failure Condenser Pressure indicator

column in condenser. vent will act on column.
(D-100) as relief
valve.
79
Chapter # 10
Instrumentation and Control
10.1. Control Loops
For instrumentation and control (24)

of different sections and equipment’s of plants, following
control loops are most often used.
1. Feedback control loop

2. Feed forward control loop
3. Ratio control loop
4. Auctioneering control loop
5. Split range control loop
6. Cascade control loop
Here is given a short outline of these control schemes, so that to justify out selection of a control
loop for specified equipment.
10.2. Components of a control system
Following are the main components of a control system:
Process
Any operation or series of operations that produce a desired final result in a process.
Measuring device
As all parts of control system, measuring element is perhaps the most important. If
measurements are not made properly the remainder of the system cannot operate satisfactorily,
also the measured variable is chosen to represent the desired conditions in the process.
Controller
The controller is the mechanism that responds to any error detecting mechanism. The output
of the controller is predetermined function of the error.
80
Final Control Element
The final control element receives the signal from the controller and by some predetermined
relationship change energy input to the process.
Control of Distillation Column
Now we discuss the Composition, Temperature, level and Pressure control for distillation
Column.
P-6
water
LT
P-8
E-2
LC
FC
DC V-2
V-5
P-3
FT Distillate
Feed
FC
stream
LT
DC = Distillation Column LC
FC= Flow Controller
E-3
FT=Flow Transmitter
LC= Level controller
LC= Level Transmitter
V1=V2=V3=V4= Control Valve V-4
bottom
Figure 10.1: Feedback Control Loops on Distillation Column
81
Chapter # 11
Environmental Impact Assessment
11.1. Project Outline
The proposed project is the production of 650 ton/day of p-xylene located in Karachi (Port
Qasim) Pakistan. The raw material use for the production of P-xylene are Toluene and
Methanol The raw material is imported. The major equipment in the proposed plant include.
1. Packed bed reactor

2. Distillation column
3. Heat exchanger
4. Flash column
5. Decanter
11.2. Site Selection
The proposed Project-site is an ideal location for the development of the Project due to the
following reasons:
 Proximity to source of LNG, where LNG will be imported and then transferred to
consumers using a network of gas pipelines.
 Availability of cooling water
 Proximity to road network for transportation of equipment
 The Project-site is located in the PQ which has a network of internal roads built for
traffic related to the construction and operation of industries within it.
 The National Highway (N-5) passes close to the PQ connecting it with other industrial
and commercial centers in Karachi and Sindh. In case of importing equipment and
transporting it to the Project-site, the PQ is host to a large commercial port
 Availability of sufficient land
 Sufficient distance from population centers;
 The PQA is a designated industrial estate with no communities located inside it.
82
11.3. Cooling-Water Technology
Once-Through Cooling is used in this project. Once-through systems withdraw water from a
natural source (typically a lake, river, or ocean), use it to extract waste heat from the steam
cycle, and then return it to the water body at a slightly elevated temperature.
11.4. Description of the Environment
The existing physical, biological and socioeconomic conditions of the surrounding areas of the
Project are described in this section. This information was collected from field surveys,
previous EIAs conducted in the Project area and other published literature.
11.5. Study Area
The description of the environment in this section focuses on an area where potential impacts
from the Project are most likely to extend. The identification of this area was a result of a desk-
based screening study conducted early in the EIA process with the objective of identifying
potential impacts from the construction and operation of the Project using available information
on Project location and design.
The Study Area delineated to be the focus of physical, biological and socioeconomic baseline
information covers the following areas and is illustrated on a map as shown in Fig. Area within
a 10 km radius of the Project-site which covers the PQA and settlements around it.
Fig 11.1: Study Area
83
11.6. Physical Baseline
Overview
The general topography of the proposed Project-site is flat and the land around the Project is a
designated industrial area. Pakistan Steel Mills (PSM) lies approximately 4 km northwest of
the Project while the K-Electric Power Station is located to its southwest. The EZ and EPCL
are located immediately to the west of the Project-site while the bulk of the remaining major
industries in PQA are located towards the northeast. Exhibit 4.1 illustrates the locations of the
major industries in the vicinity of the Project-site.
Since the Project-site is located in an industrial zone, various types of vehicles can be observed
on the roads in the Study Area. The types of vehicles seen on the roads near the Project-site
Table 11.1: Types of Vehicles Observed on Roads near the Project-Site
Water Resources in the Study Area
The main surface-water resources in the vicinity of the Project are the creeks of the Arabian
Sea, namely, Gharo Creek, 600 m south of the Project-site. The Arabian Sea is the only major
surface water body in the region. It is bordered on the north by Pakistan and Iran, on the west
by the Arabian Peninsula, and on the east by the western coast of India.
There is also a natural rainwater drain running approximately 1 km west of the Project-site,
Badal Nullah, which flows into the Gharo Creek from the north.
84
Fig 11.2: The submerged coastline 600 m south of the Project-site overlooking Gharo Creek
Fig 11.3: Badal Nullah flowing 1 km west of the Project-site into the Gharo Creek
Fig 11.4: Badal Nullah flowing from the northerly direction
85
Air Quality
The Project-site is located in the PQA, with no sensitive receptors including settlements,
schools, hospitals and mosques in the vicinity. However, during office hours, industrial
personnel working in the PQA may be exposed to the gaseous emissions from the proposed
Project which may also extend to communities outside the PQA. The intensity of the impact
on air quality due to emissions from the Project is expected to decrease with increasing distance
from the Project-site. Therefore, analyzing the airshed within a distance of 10 km from the
Project-site will be sufficient to accurately assess the impact on air quality in the PQA and the
communities surrounding it.
Socioeconomic Environment
A socioeconomic baseline study was conducted to examine the socioeconomic conditions of

communities living in settlements in the proximity of the proposed Project-site. For this
purpose, a survey was undertaken by HBP’s social team from March 13–16, 2015, which
covered 16 settlements within a 10 km radius around the Project-site. The socioeconomic
baseline information collected will be used to predict potential socioeconomic impacts of the
Project on nearby communities. The process followed for collecting the baseline information
and key-findings from the field survey are documented in this section.
Table 11.2: Socioeconomic aspects and survey results
86
11.7. Environmental Impact Assessment and Mitigation Measures for the
Proposed Project
Sources of Emission
The Project has stacks, which include the following:
11.7.1. Ethylene Emission
The plant will have one ethylene emission from the distillation column 100. The ethylene gas
is also harmful as it is also present in the natural gas. This is also a type of hydrocarbons which
can also burn due to some burnable materials or by increasing the temperature from the flash
point of the gas.
11.7.2. Toluene Emission:
Toluene is also emitted from the distillation column D-104. Toluene is also harmful component
which can cause human health problems.
11.7.3. Methanol
Biodegradability:
Biodegrades easily in water
11.7.3.1. Impacts on the Human Health
Inhalation:
Inhalation of high airborne concentrations can also irritate mucous membranes, cause
headaches, sleepiness, nausea, confusion, loss of consciousness, digestive and visual
disturbances and even death.
Eye Contact:
Methanol is a mild to moderate eye irritant. High vapor concentration or liquid contact with
eyes causes irritation, tearing and burning. This will result a high economic loss for the social
life of the people.
87
Ingestion:
Swallowing even small amounts of methanol could potentially cause blindness or death. Effects
of sub lethal doses may be nausea, headache, abdominal pain, vomiting and visual disturbances.
Effects of Long-Term Exposure:
Repeated exposure by inhalation or absorption may cause systemic poisoning, brain disorders,
impaired vision and blindness. Inhalation may worsen conditions such as emphysema or
bronchitis. Repeated skin contact may cause dermal irritation, dryness and cracking.
Impacts Removal and First Aid Measures When The Exposure Occurs
Emergency assistance may also be available from the local poison control center.
Eye Contact:
Remove contact lenses if worn. In case of contact, immediately flush eyes with plenty of clean
running water for at least 15 minutes, lifting the upper and lower eyelids occasionally. Obtain
medical attention.
Skin Contact:
In case of contact, remove contaminated clothing. In a shower, wash affected areas with soap
and water for at least 15 minutes. Seek medical attention if irritation occurs or persists. Wash
clothing before reuse.
Inhalation:
Remove to fresh air, restore or assist breathing if necessary. Obtain medical attention.
Ingestion:
Swallowing methanol is potentially life threatening. Onset of symptoms may be delayed for 18
to 24 hours after digestion. If conscious and medical aid is not immediately.
Methanol available, do not induce vomiting. In actual or suspected cases of ingestion, transport
to medical facility immediately.
88
11.7.4. Toluene
11.7.4.1.Some Physical Impacts:
This may cause central nervous system depression. May cause liver and kidney damage. This
substance has caused adverse reproductive and fetal effects in animals. Causes digestive and
respiratory tract irritation. May cause skin irritation. Aspiration hazard if swallowed. Can enter
lungs and cause damage.
Target Organs:
Kidneys, central nervous system, liver. Potential Health Effects Eye Contact: Causes eye
irritation. May result in corneal injury. Vapors may cause eye irritation.
Skin Contact:
Causes moderate skin irritation. May cause cyanosis of the extremities. Ingestion: Aspiration
hazard. May cause irritation of the digestive tract. May cause effects similar to those for
inhalation exposure. Aspiration of material into the lungs may cause chemical pneumonitis,
which may be fatal.
Environmental Mitigation Measures of the Impacts:
Different types of management is needed for the different impacts
Gas Absorbers:
Different types of gas absorbers can be used to remove the hazardous gases from the feed and
the products. Specially the charcoal absorbers are used to remove the hazardous gases because
this is less costly and can be replaced as required.
Precipitators:
Precipitators can also be used to remove the dust particles from the gas streams. Different types
of precipitators are used to remove the different types of dust from the streams.
89
11.7.5. Xylenes
Physical and Chemical Properties Physical State:
Boiling Point/Range: 279°F (137.2°C)
Appearance/Color/Odor: Colorless, light aromatic odor
Solubility in Water: Less than 0.08%
Vapor Pressure (mmHg): 2.4 at 68°F
Specific Gravity (Water=1): 0.87
Threshold: 0.5 ppm
Freezing Point: -54.0°F (-47.7°C)
11.7.5.1. Ingestion:
Liquid ingestion may result in vomiting; aspiration (breathing) of vomitus into the lungs must
be avoided as even small quantities in the lungs may result in chemical pneumonitis and
pulmonary edema/hemorrhage. Inhalation: High vapor/aerosol concentrations (greater than
approximately 1000 ppm) are irritating to the respiratory tract, may cause headaches, dizziness,
anesthesia, drowsiness, unconsciousness, and other central nervous system effects, including
death. Negligible hazard at ambient temperature (-18 to 38 Deg C; 0 to 100 Deg F)
Skin:
Prolonged and repeated liquid contact can cause defatting and drying of the skin which may
result in skin irritation and dermatitis. Eyes: Short-term liquid or vapor contact may result in
slight eye irritation. Prolonged and repeated contact may be more irritating. High vapor/aerosol
concentrations (greater than approximately 1000 ppm) are irritating to the eyes.
90
Health Hazards:
Prolonged or repeated skin contact with this product tends to remove oils possibly leading to
irritation and dermatitis; however, based on human experience and available toxicological data,
this product is judged to be neither a "corrosive" nor an "irritant" by OSHA criteria. Effects of
Overexposure: High vapor concentration (greater than approximately 1000 ppm) are irritating
to the eyes and the respiratory tract, may cause headaches and dizziness, are anesthetic, and
may have other central nervous system effects including death. Medical Conditions Generally
Aggravated by Exposure: Petroleum Solvents/Petroleum Hydrocarbons - Skin contact may
aggravate an existing dermatitis.
11.7.5.2. Ecological Impacts and its removal
Ventilation:
Use only with ventilation sufficient to prevent exceeding recommended exposure limit or
buildup of explosive concentrations of vapor in air. Use explosion-proof equipment.
Protective Clothing:
Use chemical-resistant apron or other impervious clothing, if needed, to avoid contaminating

regular clothing which could result in prolonged or repeated skin contact.
Eye Protection:
Use chemical splash goggles or face shield when eye contact may occur. Other Protective
Clothing or Equipment: Use chemical-resistant gloves, if needed, to avoid prolonged or
repeated skin contact.
Work/Hygienic Practices:
Minimize breathing vapor or mist. Avoid prolonged or repeated contact with skin. Remove
contaminated clothing; launder or dry-clean before reuse. Remove contaminated shoes and
thoroughly clean and dry before reuse. Cleanse skin thoroughly after contact, before breaks
and meals, and at end of work period. Product is readily removed from skin by waterless hand
cleaners followed by washing thoroughly with soap and water.
91
11.7.6. Conclusion
The proposed project includes the construction and operation of a new plant of production of
Para-xylene (650 ton/day) from methylation of Toluene. The project will be install at Port
Qasim Karachi. The Project will incorporate state-of-the-art equipment and effluent treatment
technologies to minimize associated wastes and mitigate their adverse impacts on the physical
and socioeconomic environment of the Project area to the maximum possible levels.
This report documented all the environmental and hazardous impacts of all the components
involved in the project and discussed all the first aid and mitigation measures to control them.
The EIA study has documented all major environmental concerns associated with the
development of the proposed Project. The EIA also documents which provides mitigation and
monitoring measures for significant environmental impacts on the existing biophysical
environmental of the Study Area.
In view of the findings of the EIA study and assuming effective implementation of the
mitigation measures and monitoring requirements, it can be concluded that all environmental
impacts of the construction and operation of the Project will be manageable and the Project
will comply with national, provincial and international standards and guidelines including
NEQS, SEQS, IFC EHS guidelines.
92
References
1. Dramola, Michael Olawale. Xylenes synthesis,characterization and physicochemical
properties.
2. Disproportionation and trans Alkylation of Alkyl benzene for zeolite catalysts. Tseng-
Chang Tsaia, Shang-Bin Liub , Ikai Wangc.
3. Process of p-Xylene Production by Highly Selective Methylation of Toluene. Muhammad
Tahir Ashraf, Rachid Chebbi,* and Naif A. Darwish. Sharjah, United Arab Emirates :
American Chemical Society, 2013.
4. [Online]
http://data.un.org/Data.aspx?q=pakistan+datamart%5BComTrade%5D&d=ComTrade&f=_l1
Code%3A30%3BrtCode%3A586 .
5. WO 2013085681 A1
6. Authmor, Kilk. Encyclopedia.
7. Sinnot, R K. Chemical Engineering Design. 3rd. Vol. Richardson and Coulson Vol 6.
8. Separation of meta and para Xylene mixture by distillation accompanied by chemical
reactions . SHOZABURO SAITO, TSUGUO.
9. Smith, McCabe and. Unit Operation of Chemical Engineering. 7th.
10. J.M.Smith. Introduction to Chemical Engineering Thermodynamics .
11. Richardson’s, Coulson and. Chemical Engineering, Volume 2, 5th editions, Particle
Technology and Separation Processes.
12. Dutta, Binay K. Principles of mass transfer and separation processes .
13. The importance of heat effects in methanol to hydrocarbons reactions over ZSM-5.
kapteijin, Irina yarulina and Freek.
14. Hibbert, John Atkinson and Carrol. AS Chemistry for AQA, advanced level chemistry .
15. Levenspiel, Octave. Chemical Reaction Engineering .
16. Perry’s. Chemical Engineering Handbook.
17. Donald, Kevin D.Dahm and. Fundamentals of chemical Engineering Thermodynamics .
18. Timmerhuas, S.peters and. Plant design and Economics for Chemical Engineers. 5th.
19. US 7321072 B2
20. Foggler. Chemical Reaction Engineering .
21. Kern, D.Q. Process Heat Transfer.
22. Silla, Harry. Chemical Process Engineering Design & Economics. s.l. : Marcel Dekker,
Inc. 2003, United Stated of America, 2003.
93
23. C.R, Branan. Rules of Thumb for Chemical Engineering. s.l. : Gulf Publishing Company,
1995, United States of America , 1995.
24. Stephnoplous. Process Control and Dynamics.
25. Y. Anjaneyulu, Valli Manickum. Environmental Impact Assessment Methodologies. s.l. :
BS Publications .
94

Final Thesis Babar

Uploaded by

Copyright:

Available Formats

Final Thesis Babar

Uploaded by

Document Information

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Final Thesis Babar

Uploaded by

Copyright:

Available Formats

Production of 650 ton/day Para-Xylene from

Dr. Ayyaz Ahmad (Assistant Professor)

DEPARTMENT OF CHEMICAL ENGINEERING

Name Registration No.

A thesis submitted in partial fulfillment of the requirement for the degree of

B.Sc. in Chemical Engineering

Dr. Ayyaz Ahmad

External Examiner’s Signature:___________________________________________

Thesis Supervisor’s Signature:____________________________________________

DEPARTMENT OF CHEMICAL ENGINEERING

Name (Registration No) Signature

Asad Ali (2014-CH-422) ________________________________

Babar Javed (2014-CH-404) ________________________________

Munawar Hussain (2014-CH-419) ________________________________

Sabir Hussain (2014-CH-410) ________________________________

CHAPTER # 01 INTRODUCTION ............................................................................... 1

CHAPTER # 02 LITERATURE REVIEW AND PROCESS SELECTION ............. 5

CHAPTER # 03 PROCESS DESCRIPTION ............................................................... 7

CHAPTER # 04 MATERIAL BALANCE ................................................................. 10

CHAPTER # 05 ENERGY BALANCE ...................................................................... 21

CHAPTER # 06 EQUIPMENT DESIGN ................................................................... 33

CHAPTER # 07 COST ESTIMATION ...................................................................... 62

CHAPTER # 08 PROCESS SIMULATION .............................................................. 69

CHAPTER # 09 HAZOP STUDY ............................................................................... 78

CHAPTER # 10 INSTRUMENTATION AND CONTROL ..................................... 80

CHAPTER # 11 ENVIRONMENTAL IMPACT ASSESSMENT ........................... 82

1.2. Para-Xylene Properties

Property Name Value

2. Used in plastic and rubber products.

3. Small amount used as solvents, coatings or pesticides.

Figure 1.1: Applications of Para-Xylene

1.4. World Wide Demand

o-xylene m-xylene p-xylene

1.5. World Wide Demand and Consumption

Figure 1.3: World Wide Demand and Consumption (3)

1.6. Para-Xylene Demand in Pakistan

 Lotte Chemicals Pakistan Limited is a sole producer of Purified Terephthalic Acid

 The capacity of plant is 500,000 tons/year of PTA.

Table 1.2: Para-Xylene Import Data for Pakistan

1.8. Capacity Selection

1. Catalytic reforming of naphtha.

2.2. Description of Available Processes

Catalytic Reforming of Toluene Methylation of Toluene

This process also produces 1. Catalyst deactivate quickly due to

1.In this process the

2.3.1Selection of the Process

 Methylation of toluene gives P-xylene selectivity of 97.5% and purity of 99.8%.Also it

3.2. Heat Exchanger (H-100, H-101, H-102, H-103)

3.3. Reactor R-100

3.4. Flash Column V-100

3.5. Three Phase Separator

3.6. Distillation Column (D-100, D-101, D-102, D-103, D-104)

D-102 is also a multi-component distillation column which is operated at 3 bar pressure.

Components Formula Molecular Boiling Points (oC)

4.2. Reactor (R-100)

4.2.1. Material Balance Steps for Reactor

1. Select suitable basis.

2. Degree of freedom analysis.

3. Apply material balance equation for reaction.