Kuwait University
Chemical Engineering Department
ChE491: PLANT DESIGN
Hysys Report
By:
Group Two:
AbdulrahmanAlbinali
Hamad Al-Kandari
Ebrahim Al-Farsi
Jaber Al-Enizi
Instructor:
Prof. Mohammed Fahim
TA:
Eng. Yusuf Ismail
I
Table of Contents
List of Figures: ............................................................................................................... 1
List of Tables: ................................................................................................................ 1
Abstract .......................................................................................................................... 2
Introduction .................................................................................................................... 3
HYSYS Simulation Program ......................................................................................... 4
Process Description ........................................................................................................ 6
Main Equipments ........................................................................................................... 9
Comparison Between Our Design and Reference Values ........................................... 13
Conclusion ................................................................................................................... 16
References .................................................................................................................... 17
List of Figures:
Figure 1: Defining the components in the process......................................................... 4
Figure 2: Defining the fluid packages ............................................................................ 5
Figure 3: Defining the reaction for simulation .............................................................. 5
Figure 3: PFD for convnetional nitration ....................................................................... 7
Figure 3: PFD for adibiatic nitration .............................................................................. 8
Figure 4: Distillation column T-100 .............................................................................. 9
Figure 5: Distillation column T-101 ............................................................................ 10
Figure 6: Reactors R-100 ............................................................................................. 11
Figure 7: Flash tank V-101 .......................................................................................... 12
III
List of Tables:
Table 1: Overhead and bottoms composition of distillation T-100………………….9
Table 2: Overhead and bottoms composition of distillation T-101…………… ……10
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Abstract
In this report, the material and energy balance for the production of Nitrobenzene by
conventional nitration and adiabatic nitration . It has been estimated by simulating the
process flow sheet using chemical engineering simulation program (HYSYS). Many
assumptions were made to simplify simulation process. The reaction section, , distillation and
other main equipment section used in the simulation have been reported individually in this
report. The resulting Nitrobenzene from this plant has flow rate of 136 thousand tons/yr.
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Introduction
Nitrobenzene is an organic compound with the chemical formula C6H5NO2.
Nitrobenzene is important in the petrochemical industry . About 95% of nitrobenzene
is used in the production of aniline, which is an introduction to the chemical, rubber,
pesticides, dyes and explosives, and pharmaceuticals.
The production of nitrobenzene include: conventional nitration and adiabatic nitration .
This report will focus on the conventional nitration .
Reactions occur during the Conventional Nitration of Nitrobenzene :
Main reaction:
Overall mass balance:
Benzene
Nitric Acid
Nitrobenzene
O. M. B
Water
Sulfuric Acid
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HYSYS Simulation Program
Hysys is powerful engineering simulation software that was created by
Hyprotech for simulation of chemical plants and oil refineries. It includes tools for
estimation of physical properties and liquid-vapor phase equilibrium, heat and
material balances, and simulation of many types of chemical engineering equipment.
Hysys is very effective software especially for steady state simulation and for
petroleum products. It has a lot of thermodynamics method to estimate the properties
of streams in a process and a lot of equations of state exist in the database of the
program. It is widely used in universities in introductory and advanced courses
especially in chemical engineering.
First Step in Simulation:
Before entering the hysys simulation environment we have to go through some steps. These
steps are:
1- Defining the components.
2- Defining the fluid packages.
3- Defining the reactions.
Defining the components:
Figure 1: Defining the components in the process
The components were taken from the material balance and Nitrobenzene reactions.
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Defining the fluid packages:
Figure 2: Defining the fluid packages
The fluid package is used to estimate the properties of the compounds. The fluid packages
used are UNIQUAC and GCEOS.
Defining the reactions for simulation:
Figure 3: Defining the reaction for simulation
There is one main reaction in this process. The reactants and products of each reaction were
defined. For each one, the stoichiometry coefficients and conversion percent for the reaction
were defined.
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Process Description
Conventional Nitration:From the above PFD figure , Benzene (stream 1) and recycled benzene (stream 35)
are stored in a tank and then sent to a extractor along with stream 13 which is mostly
sulfuric acid to extract most of the benzene in stream 13 and then sent to a separator
that separates benzene (stream 10) from the acids (stream 9) , the benzene is sent to
the reactor along with the mixed acid of HNO3 (stream 2) and H2SO4 (stream 3) , the
mixture (stream 4) is reacted with benzene (stream 10) to produce crude mixture
(stream 11) and then it is sent to a separator which separates nitrobenzene (stream 12)
from separates acids stream (stream 13) that covers the nitration section . The crude
nitrobenzene (stream 12) is sent to the purification section . First of all the crude
nitrobenzene is mixed with NaOH (stream 20) in caustic wash vessel and it goes through a
several washing system to get rid of the acids and impurities . after the washers it is sent to
2 distillation columns , first it is heated and then fed to the first distillation (stream 29)
It separates the the benzene from the nitrobenzene the benzene is recycled
(stream 35) and the pure nitrobenzene (stream 37) is cooled in a heat exchanger
from the nitrobenzene (stream 29) , the pure nitrobenzene is sent to a storage tank .
Adiabatic nitration:Benzene (stream 1) and a recycled benzene ( stream 35) are stored in a tank and then sent
to the reactor , HNO3 (stream 2) and H2SO4 (stream 3) are mixed to produce stream 4
(mixed acid) . the benzene and the mixed acid are reacted at high temperatures to produce
crude mixture (stream 11) and then to a settling drum to get most of the nitrobenzene
which will be sent to the same purification section.
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Figure 4: PFD Diagram of Acetaldehyde Production
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Main Equipments for Conventional Nitration
Distillation Column:
Distillation is a method of separating mixtures based on differences in volatilities of
components in a boiling liquid mixture. Distillation is a unit operation, or a physical
separation process, and not a chemical reaction .
The application of distillation can roughly be divided in four groups: laboratory scale,
industrial distillation, distillation of herbs for perfumery and medicinal (herbal
distillate), and food processing. The latter two are distinctively different from the
former two in that in the processing of beverages, the distillation is not used as a true
purification method but more to transfer all volatiles from the source materials to the
distillate.
In our plant, we have two distillation columns, as we will see in next papers. Each
distillation column has its properties that it operates at it. The next tables show the
properties for these distillation columns.
Table 1: Overhead and bottoms composition of distillation T-100
Distillation T-100
Overhead Product
Comp.
%wt
0.2392
Benzene
0
HNO3
0.327
NITROBENZENE
0.4338
H2O
0
H2SO4
Bottoms Product
%wt
0
0
1
0
0
Figure 4: Distillation column T-100
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Table 2: Overhead and bottoms composition of distillation T-101
Distillation T-100
Overhead Product
Comp.
%wt
0.2392
Benzene
.0036
HNO3
0.0097
NITROBENZENE
0.965
H2O
0
H2SO4
0.0118
NAOH
Bottoms Product
%wt
0
0
1
0.9965
0.0035
0
Figure 5: Distillation column T-101
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Reactor:
All chemical processes are centered in the chemical reactor. A reactor is a vessel
designed for internal pressure or vacuum, has a heat source typically an external
jacket, and or internal cooling coils.
Chemical engineers design reactors to maximize net present value for the given
reaction. Designers ensure that the reaction proceeds with the highest efficiency
towards the desired output product, producing the highest yield of product while
requiring the least amount of money to purchase and operate .
In our plant, we have four reactors, as we see below. It operates at temperature at
almost 60K and pressure 101.3 kPa and the reactions which occurs in it produce
benzene , HNO3 , NITROBENZENE , H2O and H2SO4 .
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Flash Tank:
Flash (or partial) evaporation is the partial vapor that occurs when a saturated liquid
stream undergoes a reduction in pressure by passing through a throttling valve or
other throttling device. This process is one of the simplest unit operations. If the
throttling valve or device is located at the entry into a pressure vessel so that the flash
evaporation occurs within the vessel, then the vessel is often referred to as a flash
drum .
In our flash tank (V-101), as shown below, we used it to separate a mixture of vapor
and liquid (vapor phase 0%).
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Comparison Between Our Design and Reference Values
In this section we want to compare between our results which we got it from HYSYS
with the values got it from the reference.
Table 3: Comparison between reference and our design values
Mole Flowrate
1
2
3
(lb/hr)
Ref.
Design
Ref.
Design
Ref.
Design
Benzene
24447
24447
-
-
-
-
Nitric Acid
-
-
19779
19779
-
-
Sulfuric Acid
-
-
-
-
413
413
Water
-
-
11616
11616
22
22
Nitrobenzene
-
-
-
-
-
-
Mole Flowrate
4
5
10
(lb/hr)
Ref.
Design
Ref.
Design
Ref.
Design
Benzene
-
-
24773
24773
24501
24501
Nitric Acid
19779
19779
-
-
-
-
Sulfuric Acid
43575
43575
-
-
43
43
Water
14882
28875
2
2
51
51
Nitrobenzene
-
-
-
-
418
418
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Mole Flowrate
11
12
21
(lb/hr)
Ref.
Design
Ref.
Design
Ref.
Design
Benzene
368
367.41
331
331
368
536.8
Nitric Acid
247
309.9
147
147
-
100.83
Sulfuric Acid
43618
43618
196
196
-
306
Water
20508
34525
155
155
10161
215
Nitrobenzene
38379
38421
38110
38110
38495
39160
Mole Flowrate
29
30
37
(lb/hr)
Ref.
Design
Ref.
Design
Ref.
Design
Benzene
331
367.41
38
671
3
tr
Nitric Acid
-
309.9
-
200
-
-
Sulfuric Acid
-
43618
-
293
-
-
Water
145
34525
10199
30440
16
tr
Nitrobenzene
38052
38421
405
1044
38052
38858
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After reading values of previous table we noticed that the difference between
reference and our design streams are very small except the water stream.
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Conclusion
Hysys simulator was used to simulate this process and it is a powerful tool. Energy and mass
balances were calculated easily by this software. Conventional nitration appeared to be a very
efficient process for the production of Nitrobenzene which was produced in 136 thousand
tons/yr .
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References
Web Sites:
1. Clarkson: http://people.clarkson.edu/~wwilcox/Design/refhysys.htm
2. Utm:http://eprints.utm.my/3030/2/HYSYS_for_UTM_Degree%2B%2B_Program.
pdf
3. Wikipedia: http://en.wikipedia.org/wiki/Distillation
4. Wikipedia: http://en.wikipedia.org/wiki/Chemical_reactor
5. Ippe: http://www.ippe.com/EquipmentSearch/tabid/103/CategoryId/REACTOR
6. Cgs: http://www.cgscgs.com/ga_tt.htm
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