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HYSYS 8 8 - Manual

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AspenTech Incorporations 
Aspen Hysys V8.8 
Anees Ahmad
Typewriter
Cases Solved in Hysys Version 8.0 are same as Version 8.8
Anees Ahmad
Typewriter
 
 
 
 
 
 
 
 
 
 
Chemical Process Principles 
 
 
 
 
 
 
 
 
Matbal-001H Revised: Nov 7, 2012 
 1 
Cyclohexane Production with Aspen HYSYS® V8.0 
 Lesson Objectives 1.
 
 Construct an Aspen HYSYS flowsheet simulation of the production of cyclohexane via benzene 
hydrogenation 
 Become familiar with user interface and tools associated with Aspen HYSYS 
 Prerequisites 2.
 
 Aspen HYSYS V8.0 
 Knowledge of chemical process operations 
 Background/Problem 3.
 
Construct an Aspen HYSYS simulation to model the production of cyclohexane via benzene hydrogenation. The 
simplified flowsheet for this process is shown below. Fresh benzene and hydrogen feed streams are first fed 
through a heater to bring the streams up to reactor feed temperature and pressure conditions. This feed 
mixture is then sent to a fixed-bed catalytic reactor where 3 hydrogen molecules react with 1 benzene molecule 
to form cyclohexane. This simulation will use a conversion reactor block to model this reaction. The reactor 
effluent stream is then sent to a flash tank to separate the light and heavy components of the mixture. The 
vapor stream coming off the flash tank is recycled back to the feed mixture after a small purge stream is 
removed to prevent impurities from building up in the system. The majority of the liquid stream leaving the flash 
tank goes to a distillation column to purify the cyclohexane product, while a small portion of the liquid stream is 
recycled back to the feed mixture to minimize losses of benzene. Process operating specifications are listed on 
the following page. 
 
Matbal-001H Revised: Nov 7, 2012 
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Feed Streams 
Benzene Feed (BZFEED) Composition (mole fraction) 
Hydrogen - 
Nitrogen - 
Methane - 
Benzene 1 
Total Flow (lbmol/hr) 100 
Temperature (°F) 100 
Pressure (psia) 15 
 
Hydrogen Feed (H2FEED) 
Hydrogen 97.5 
Nitrogen 0.5 
Methane 2.0 
Benzene - 
Total Flow (lbmol/hr) 310 
Temperature (°F) 120 
Pressure (psia) 335 
 
Distillation Column 
Number of stages 15 
Feed stage 8 
Reflux Ratio 1.2 
Cyclohexane recovery 99.99 mole % in bottoms 
Condenser Pressure 200 psia 
Reboiler Pressure 210 psia 
 
Feed Preheater 
Outlet Temperature 300 °F 
Outlet Pressure 330 psia 
 
Reactor 
Stoichiometry Benzene + 3H2  Cyclohexane 
Conversion 99.8% of benzene 
Outlet temperature 400°F 
Pressure drop 15psi 
 
Flash Tank 
Temperature 120°F 
Pressure drop 5psi 
 
Purge Stream 
Purge rate is 8% of vapor recycle stream 
 
Liquid Split 
70% of liquid stream goes to distillation column 
 
 
The examples presented are solely intended to illustrate specific concepts and principles. They may not 
reflect an industrial application or real situation. 
 
Matbal-001H Revised: Nov 7, 2012 
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 Aspen HYSYS Solution 4.
 
4.01. Start Aspen HYSYS V8.0, select New on the Start Page to start a new simulation. 
 
4.02. Create a component list. In the Component Lists folder, select the Add button to create a new HYSYS 
component list. 
 
 
 
4.03. Define components. Use the Find button to select the following components: Hydrogen, Nitrogen, 
Methane, Benzene, and Cyclohexane. 
 
 
4.04. Select a property package. In the Fluid Packages folder in the navigation pane click Add. Select SRK as 
the property package. 
 
 
 
Matbal-001H Revised: Nov 7, 2012 
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4.05. We must now specify the reaction involved in this process. Go to Reactions folder in the navigation 
pane and click Add to add a reaction set. 
 
 
 
4.06. In Reactions | Set-1 select Add Reaction. Select the Hysys radio button and select Conversion. Then 
click Add Reaction. Once a new reaction (Rxn-1) can be seen on the reaction set page, close the 
Reactions window shown below. 
 
 
 
4.07. Double click on Rxn-1 to define the reaction. In the reaction property window, add components 
Benzene, Hydrogen, and Cyclohexane to the Stoichiometry Info grid. Enter -1, -3, and 1, respectively, 
for stoichiometry coefficients. In the Basis grid select Benzene as Base Component, Overall for Rxn 
Phase, 99.8 for Co, and 0 for both C1 and C2. This indicates that the reaction will convert 99.8% of 
benzene regardless of temperature. Close this window when complete. 
 
Matbal-001H Revised: Nov 7, 2012 
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4.08. Attach this reaction set to a fluid package by clicking the Add to FP button. Select Basis-1 and click Add 
Set to Fluid Package. The reaction set should now be ready. 
 
 
 
4.09. We are now ready to enter the simulation environment. Click the Simulation button in the bottom left 
of the screen. 
 
 
Matbal-001H Revised: Nov 7, 2012 
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4.10. First we will place a Mixer and a Heater block onto the flowsheet. 
 
 
 
4.11. Double click on the mixer (MIX-100) to open the mixer property window. Create 2 inlet streams: 
H2FEED, BZFEED; and 1 outlet stream: ToPreHeat. 
 
Matbal-001H Revised: Nov 7, 2012 
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4.12. Go to the Worksheet tab to define streams H2FEED and BZFEED. First we will define the Conditions of 
each stream. For H2FEED, enter a Temperature of 120°F, a Pressure of 335 psia, and a Molar Flow of 
310 lbmole/hr. For BZFEED, enter a Temperature of 100°F, a Pressure of 15 psia, and a Molar Flow of 
100 lbmole/hr. Note that you can change the global unit set to Field if the units are different than those 
displayed below. 
 
 
Matbal-001H Revised: Nov 7, 2012 
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4.13. Next we will define the Composition of the two feed streams. In the Worksheet tab go to the 
Composition form. Enter the compositions shown below. You will notice that after inputting the 
composition, the mixer will successfully solve for all properties. 
 
 
 
 
4.14. Double click on the heater block (E-100) to configure the heater. Select stream ToPreHeat as the inlet 
and create an outlet stream called R-IN. Add an energy stream called PreHeatQ. 
 
Matbal-001H Revised: Nov 7, 2012 
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4.15. Go to the Worksheet tab and specify the outlet stream R-IN temperature and pressure. Enter 300°F for 
Temperature and 330 psia for Pressure. 
 
 
 
 
Matbal-001H Revised: Nov 7, 2012 
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4.16. The flowsheet should look like the following at this point. 
 
 
4.17. We will now add a Conversion Reactor to the flowsheet. Press F12 on the keyboard to open the 
UnitOps window. Select the Reactors radio button and select Conversion Reactor. Press Add. 
 
 
 
4.18. In the Conversion Reactor property window, select the inlet stream to be R-IN, and create a Liquid 
Outlet called LIQ and a Vapour Outlet called VAP. In the Parameters form, enter a Delta P of 15 psi. 
 
Matbal-001H Revised: Nov 7, 2012 
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Matbal-001H Revised: Nov 7, 2012 
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4.19. In the Reactions tab, select Set-1 for Reaction Set. Notice that when the reactor solves, the contents of 
the reactor are entirely in the vapor phase, therefore there is no liquid flow leaving the bottom of the 
reactor. 
 
 
 
 
 
 
 
 
 
 
 
 
Matbal-001H Revised: Nov 7, 2012 
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4.20. Next we will add a Cooler to the main flowsheet to cool down the vapor stream leaving the reactor. 
 
 
 
4.21. Double click on the cooler block (E-101) to open the cooler property window. Select VAP as the inlet 
stream and create an outlet stream called COOL. Also add an energy stream called COOLQ. In the 
Parameters form enter a Delta P of 5 psi. 
 
 
Matbal-001H Revised: Nov 7, 2012 
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4.22. Go to the Worksheet tab to specify the outlet stream temperature. Enter 120°F for the Temperature of 
stream COOL. The cooler will solve. 
 
 
 
 
Matbal-001H Revised: Nov 7, 2012 
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4.23. We will now add a Separator block to separate the vapor and liquid phases of stream