Chemical engineering simulations

AspenTech Incorporations
Aspen Hysys V8.8
Cases Solved in Hysys Version 8.0 are same as Version 8.8

Matbal-001H Revised:Nov7,2012
1
Cyclohexane Production with Aspen HYSYS® V8.0
Lesson Objectives1.
 Constructan Aspen HYSYS flowsheetsimulationof the productionof cyclohexane viabenzene
hydrogenation
 Become familiarwithuserinterface and toolsassociatedwithAspenHYSYS
Prerequisites2.
 Aspen HYSYS V8.0
 Knowledgeof chemical processoperations
Background/Problem3.
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 preventimpurities from building upin the system. The majority of the liquid streamleaving 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 followingpage.

2
FeedStreams
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
DistillationColumn
Number of stages 15
Feed stage 8
Reflux Ratio 1.2
Cyclohexane recovery 99.99 mole % inbottoms
Condenser Pressure 200 psia
ReboilerPressure 210 psia
FeedPreheater
Outlet Temperature 300 °F
Outlet Pressure 330 psia
Reactor
Stoichiometry Benzene +3H2  Cyclohexane
Conversion 99.8% ofbenzene
Outlet temperature 400°F
Pressure drop 15psi
Flash Tank
Temperature 120°F
Pressure drop 5psi
Purge Stream
Purge rateis 8% ofvaporrecyclestream
LiquidSplit
70% ofliquidstreamgoes todistillationcolumn
The examplespresentedare solely intendedtoillustrate specificconceptsand principles. Theymay not
reflectan industrial application or real situation.

3
Aspen HYSYS Solution4.
4.01. Start AspenHYSYS V8.0, selectNewon the Start Page to start a new simulation.
4.02. Create a componentlist. Inthe ComponentLists folder,selectthe Addbuttonto create a newHYSYS
componentlist.
4.03. Define components. Use the Find button to select the following components: Hydrogen, Nitrogen,
Methane, Benzene,andCyclohexane.
4.04. Select a property package. In the Fluid Packages folder in the navigation pane click Add. Select SRK as
the propertypackage.

4
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 reactionset.
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 windowshownbelow.
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 regardlessof temperature. Close thiswindow whencomplete.

5
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 FluidPackage. The reactionsetshouldnow be ready.
4.09. We are now ready to enter the simulation environment. Click the Simulation button in the bottom left
of the screen.

6
4.10. Firstwe will place aMixer anda Heater blockontothe flowsheet.
4.11. Double click on the mixer (MIX-100) to open the mixer property window. Create 2 inlet streams:
H2FEED, BZFEED; and 1 outletstream: ToPreHeat.

7
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
displayedbelow.

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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 mixerwillsuccessfullysolve forall properties.
4.14. Double click on the heater block (E-100) to configure the heater. Select stream ToPreHeat as the inlet
and create an outletstreamcalled R-IN. Addan energystreamcalled PreHeatQ.

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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 psiafor Pressure.

10
4.16. The flowsheetshouldlooklike the followingatthispoint.
4.17. We will now add a Conversion Reactor to the flowsheet. Press F12 on the keyboard to open the
UnitOpswindow. Selectthe Reactorsradiobuttonand select ConversionReactor. Press Add.
4.18. In the Conversion Reactor property window, select the inlet stream to be R-IN, and create a Liquid
OutletcalledLIQ and a Vapour Outlet calledVAP. Inthe Parametersform, entera Delta P of 15 psi.

11

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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.

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4.20. Nextwe will addaCooler to the mainflowsheettocool downthe vaporstreamleavingthe 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 formentera Delta P of 5 psi.

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4.22. Go to the Worksheet tab to specify the outlet stream temperature. Enter 120°F for the Temperature of
streamCOOL. The coolerwill solve.

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4.23. We will now add a Separator block to separate the vapor and liquid phases of stream COOL. From the
model palette addaSeparator to the flowsheet.
4.24. Double click on the separator block(V-100). Select COOL as the inlet stream and create liquid and vapor
outletstreamscalled LIQ1and VAP1. The separatorshouldsolve.

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4.25. The flowsheetshouldnowlooklikethe following.
4.26. We will now add 2 Tee blocks, 1 for each of the separator outlet streams. One tee will be used to purge
a portion of the vapor stream to prevent impurities from building up in the system. The other tee will
be used to recycle a portion of the liquid back to the mixer and the rest of the liquid will be fed to a
distillationcolumn.

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4.27. Double click on the first Tee block (TEE-100). Select stream VAP1 as the inlet, and create 2 outlet
streamsVAPREC,and PURGE.

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4.28. Go to the Parameterspage and enter0.08 for the Flow Ratio for streamPURGE.
4.29. You can rotate the icon for a block by selecting the icon and clicking the Rotate button in the
Flowsheet/Modifytabinthe ribbon.

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4.30. Double click the second Tee block (TEE-101). Select LIQ1 for the inlet stream and create 2 outlet
streamsLIQREC, and ToColumn.
4.31. In the Parameters tab entera FlowRatio of 0.7 for streamToColumn.

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4.32. The flowsheetshouldnow looklikethe following.
(FAQ) UsefulOption To Know:Saving Checkpoints
Save “checkpoints” as you go. Once you have a working section of the flowsheet, save as a new
file name, so you can revert to an earlier checkpoint if the current one becomes too complex to
troubleshootorconvergence errorsbecomepersistent.

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4.33. We are now ready to connect the recycle streams back to the mixer. On the main flowsheet, add 2
Recycle blocks.

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4.34. Double click on the first recycle block (RCY-1). Select stream VAPREC as the inlet stream and create an
outletstreamcalled VAPToMixer.
4.35. Double click the second recycle block (RCY-2). Select LIQREC as the inlet stream and create an outlet
streamcalled LIQToMixer.

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4.36. Connect the recycle streams back to the mixer. Double click the mixer block (MX-100). On the Design |
Connectionssheetadd LIQToMixerand VAPToMixeras inletstreams. The flowsheetshouldconverge.
4.37. The flowsheetshouldnowlooklikethe following.

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4.38. We are now ready to add the distillation column to the flowsheet. From the Model Palette add a
DistillationColumnSub-Flowsheet.
4.39. Double click on the Distillation Column Sub-flowsheet. This will launch the Distillation Column Input
Expert. Enter 15 for # Stages and specify ToColumn as inlet stream on stage 8_Main TS. Select Full
Reflux for Condenser, create an Ovhd Vapour Outlet stream called Off Gas, create Bottoms Liquid
Outletstreamcalled Bot, and adda CondenserEnergyStream calledCondQ. Whenfinishedclick Next.

25
4.40. On page 2 of the Distillation Column Input Expert keep the default selections for Reboiler Configuration
and click Next.

26
4.41. On page 3 of the Distillation Column Input Expert enter a condenser pressure of 200 psia and a reboiler
pressure of 210 psia. ClickNext.
4.42. On page 4 of the Distillation Column Input Expert leave fields for temperature estimates blank and click
Next. On the final page of the column expert enter a molar Reflux Ratio of 1.2 and click Done to
configure the column.

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4.43. After completing the input for the column expert the Column property window will open. We want to
create a design specification in order to ensure that 99.99% of the cyclohexane is recovered in the
bottoms stream. Go to the Design | Specs sheet. Click Add and select Column Component Recovery.
In the Comp Recovery window specify Stream for Target Type, Bot@COL1 for Draw, 0.9999 for Spec
Value,and Cyclohexane forComponents. Close thiswindow whenfinished.

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4.44. Go to the Specs Summary sheet and make sure that the only active specs are Reflux Ratio and Comp
Recovery. The columnshouldconverge.
4.45. The flowsheetisnowcomplete andshouldlooklike the following.

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Thisflowsheetisnowcomplete.
Conclusion5.
This is a simplified process simulation, however you should now have learned the basic skills to create and
manipulate asteadystate chemical processsimulationinAspenHYSYSV8.0.
Copyright6.
Copyright © 2012 by Aspen Technology, Inc. (“AspenTech”). All rights reserved. This work may not be
reproduced or distributed in any form or by any means without the prior written consent of
AspenTech. ASPENTECH MAKES NO WARRANTY OR REPRESENTATION, EITHER EXPRESSED OR IMPLIED, WITH
RESPECT TO THIS WORK and assumes no liability for any errors or omissions. In no event will AspenTech be
liable to you for damages, including any loss of profits, lost savings, or other incidental or consequential
damages arising out of the use of the information contained in, or the digital files supplied with or for use with,
thiswork. This workand itscontentsare providedforeducational purposesonly.
AspenTech®, aspenONE®, and the Aspen leaf logo, are trademarks of Aspen Technology, Inc.. Brands and
productnamesmentioned inthisdocumentationare trademarksorservice marksof theirrespective companies.

1
Calculation of Gasoline Additives with Aspen HYSYS® V8.0
1. Lesson Objectives
 Learn howto specifyamixer
 Learn howto use the spreadsheetinAspen HYSYStoperformcustomizedcalculations
2. Prerequisites
3. Background
Ethyl tert-butyl ether(ETBE) isan oxygenate thatisaddedtogasoline toimprove ResearchOctane Number
(RON) andto increase oxygencontent. The goal isto have 2.7% oxygenbyweightinthe final product. The legal
limitisthatETBE cannot exceed more than17% byvolume. Forsimplicity,we use 2,2,4-trimethylpentane to
representgasoline. Since ETBE'smolecularweightis102.18 g/mol, the ETBE in the productstream can be
calculatedasfollowing:
Thisyields17.243% of ETBE byweightinthe productstream. Giventhis,the spreadsheettool canbe utilizedto
target the ETBE feedtoachieve the desiredoxygencontent.
In thistutorial we will calculate:
 For a certainflowrate of gasoline (e.g.,100 kg/hr),how muchETBE shouldbe addedto achieve the
oxygencontentof 2.7% byweightinthe blendedgasoline.
 Checkwhetherornot the legal limitof ETBE contentissatisfied.
A HYSYS spreadsheetis usedtoperformcalculationsoneachcriterion. Both targetsshouldbe metinthe
simulation.
The examplespresentedare solelyintendedtoillustrate specificconceptsand principles. Theymay not

2
4. Aspen HYSYS Solution
4.01. Start a newsimulationin AspenHYSYSV8.0.
4.02. Create a componentlist. Inthe ComponentLists folderselectAdd. Add2,2,4-trimethylpentane and
ETBE to the componentlist.
4.03. Define propertypackage. Inthe FluidPackagesfolderselectAdd. SelectPeng-Robinsonasthe
propertypackage.
4.04. Enter the simulationenvironmentbyclickingthe Simulationbuttoninthe bottomleftof the screen.
4.05. Adda Mixerto the flowsheetfromthe Model Palette.

3
4.06. Double clickonthe mixer(MIX-100). Create two InletscalledETBE and Gasoline. Create anOutlet
calledBlend.

4
4.07. Define feedstreams. Goto the Worksheettab. For streamETBE entera Temperature of 25°C and a
Pressure of 1 bar. Leave Mass Flowemptyas we will solve foritlater.
4.08. In the Compositionformunderthe Worksheettab,entera Mole Fraction of 1 for ETBE in the ETBE feed
stream.

5
4.09. Define gasoline feedstream. Inthe Conditionsforminthe Worksheettab,entera Temperature of
25°C, a Pressure of 1 bar, anda Mass Flowof 82.76 kg/h.
4.10. In the Compositionformentera Mole Fraction of 1 for 224-Mpentane inthe Gasoline stream. The
gasoline streamshouldsolve.However.the mixerwill notsolve because the flowrate of ETBE is still
unknown.

6
4.11. We will nowcreate aspreadsheettocalculate the targetmassflowrate of streamETBE. Adda
Spreadsheettothe flowsheetfromthe Model Palette.

7
4.12. Double clickonthe spreadsheet(SPRDSHT-1). Goto the Spreadsheettaband enterthe followingtextin
cellsA1 and A2.

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4.13. Rightclickon cell B1 andselectImport Variable. Selectthe followingtoimportthe MassFlowof stream
Gasoline tocell B1. Press OK whencomplete.
4.14. Clickcell B2 and enterthe followingformula: =(B1*0.17243) / (1-0.17243). This will calculate the mass
flowrate for streamETBE. Fromthe backgroundsection,we know thatinorderto reach the oxygen
contentgoal of 2.7%, we will needthe gasoline streamtocontain17.243% ETBE by weight.

9
4.15. We nowwishto exportthe calculatedflow rate incell B2to streamETBE. Rightclickcell B2 and select
Export Formula Result. Make the followingselectionsandclick OKwhencomplete. The mixershould
nowsolve.

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4.16. We will nowcalculate the volumepercentof ETBEin the blendedstreamtomake sure thatthe ETBE
contentisbelowthe legal limitof 17volume percent. Thiscaneasilybe observedinthe spreadsheet. In
the spreadsheet,enterthe followingtextincell A4.
4.17. Rightclickon cell B4 andselectImport Variable.Make the followingselectionstoimport MasterComp
Volume Frac of ETBE inthe blendedstream. Click OKwhencomplete.

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4.18. The volume fractionof ETBE inthe blendedstreamis0.1596, whichis below the legal limitof 0.17. It is
determinedthatthe targetflowrate of ETBE to be mixedwiththisgasoline streamis17.24 kg/h.

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5. Conclusions
For a specifiedgasolinemassflowrate of 82.76 kg/hr,17.24 kg/hrof ETBE isneededtoachieve 2.7% oxygen
contentbyweightinthe final product. Furthermore,afterblending,the productdoesnotexceedthe legallimit
for ETBE of 17% byvolume. If gasoline containsasingle component,manualcalculationshouldbe easywithout
a simulator. However,real gasoline containsmanyunknowncomponentsandgasoline’scontentsvaryas
feedstockorplantoperationconditionschange. Therefore,manual calculationbecomesverydifficultandthe
use of a simulatorsuchas Aspen HYSYScan be helpful tocarryout the calculation.
6. Copyright
Copyright© 2012 by AspenTechnology,Inc.(“AspenTech”).All rightsreserved. Thisworkmaynot be
reproducedordistributedinanyformor byany meanswithoutthe priorwrittenconsentof
AspenTech. ASPENTECHMAKESNOWARRANTYOR REPRESENTATION,EITHER EXPRESSEDOR IMPLIED, WITH
RESPECT TO THIS WORK and assumesnoliabilityforanyerrorsor omissions. Innoeventwill AspenTechbe
liable toyoufordamages,includinganylossof profits,lostsavings,orotherincidental orconsequential
damagesarisingoutof the use of the informationcontainedin,orthe digital filessuppliedwithorforuse with,
AspenTech®,aspenONE®,andthe Aspenleaf logo,are trademarksof AspenTechnology,Inc.. Brandsand
productnamesmentionedinthisdocumentationare trademarksorservice marksof theirrespective companies.

Thermodynamics for Chemical Engineers

Prop-001H Revised:Nov16,2012
1
Generate Ethylene Vapor Pressure Curves with Aspen HYSYS® V8.0
 Generate vaporpressure curvesforEthylene
2. Prerequisites
 Introductiontovapor-liquidequilibrium
3. Background
Separationprocessesinvolvingvapor-liquidequilibrium exploitvolatilitydifferenceswhich are indicatedbythe
components’ vaporpressure. Highervaporpressure meansacomponentismore volatile.
Ethylene isanimportantmonomerforpolymersandthere are manyethyleneplantsaroundthe world. A vital
stepinethylene productionisseparatingitfromothercompoundsandasa resultthe vapor pressure of
ethylene isanimportantphysical propertyforethyleneproduction.
4. Problem Statement and Aspen HYSYS Solution
Problem Statement
Determine the vaporpressure of ethylene at5 °C, and itsnormal boilingpoint. Alsocreate aplotof vapour
pressure versustemperature.
Aspen HYSYS Solution
4.01. Create a newsimulationin AspenHYSYSV8.0.
4.02. Create a componentlist. Inthe ComponentList folderselectAdd. AddEthylene tothe componentlist.

2
4.03. Double clickon Ethylene to viewthe pure componentproperties. Goto the Critical tab. Make a note
that the Critical Temperature is9.2°C and the Normal BoilingPoint is-103.8°C.

3
4.04. Define propertymethods. Goto the FluidPackages folderandclick Add. SelectPeng-Robinsonasthe
propertypackage.
4.05. Move to the simulationenvironment. Clickthe Simulationbuttoninthe bottomleftof the screen.
4.06. Adda Material Stream to the flowsheet.

4
4.07. Double clickonmaterial stream(1).The vapor pressure of liquidisthe atmosphericpressureatwhicha
pure liquidboilsata giventemperature. The pointatwhichthe firstdropof liquidbeginstoboil is
calledthe bubble point,whichisfoundinHYSYSby specifyingavapourfraction of 0. Therefore,we can
findthe vaporpressure of pure liquidbyspecifyingatemperature andvapourfractionof 0.
4.08. In material stream 1,entera Vapour Fraction of 0, a Temperature of 5°C, and a Molar Flow of 1
kgmole/h. In the Compositionformunderthe Worksheettab entera Mole Fraction of 1 for Ethylene.
4.09. You can see that the Pressure is45.93 bar. Thisis equivalenttothe vapourpressure of ethylene atthis
temperature. Nextwe wouldliketodetermine the normal boilingpointof ethylene. Insteadof
specifyingtemperature,we will specifypressure. Emptythe fieldfortemperature andenteravalue of 1
bar forPressure.

5
4.10. The newlycalculatedtemperature is -104.3°C. Thisisthe boilingtemperature of ethylene atapressure
of 1 bar.
4.11. Nextwe wouldlike tocreate aplotof vapourpressure versustemperature. First,inthe Material
Stream 1 window,emptythe fieldfor Pressure andenterany Temperature (below critical temperature).
Thiswill allowustovary temperature whenwe performacase study. Go to the Case Studiesfolderin
the Navigation Pane and click Add.

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4.12. In Case Study 1, click Add to selectthe variables. Select the Temperature andPressure of stream1. In
the IndependentVariable fieldenteraLow Bound of -150°C, a High Bound of 0°C, and a Step Size of
10°C. Click Run.

7
4.13. Afterrunningthe case study,go to the Plotstab. Here youwill see aplotof Pressure vs Temperature.

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4.14. Note that bylookingatthe plotyoucan verifythatat around -104°C the vapourpressure if
approximately1bar, indicatingthe normal boilingpoint.
5. Conclusions
As we can see fromthe generated plot,ethylene isaveryvolatile component. At5°C, itsvapor pressure is
about45.93 bar. From thisanalysis,we alsosee thatethylene’s normal boilingpointtemperature isabout –104
°C.
6. Copyright
Copyright© 2012 by AspenTechnology,Inc. (“AspenTech”). All rightsreserved. Thisworkmaynotbe

1
Retrieve Pure Component Property Data with Aspen HYSYS® V8.0
 Learn howto retrieve property dataforpure componentsinAspen HYSYS.
2. Prerequisites
 AspenHYSYS V8.0
3. Background
There are manyreasonsthat we needphysical propertiesof pure components.
Whenwe lookfor a solventforextractive distillation(atechnologythatusesathirdcomponent,the solvent,to
separate twocomponentsinamixture thatare difficulttoseparate directlyviadistillation),we lookfor
componentswithnormal boilingpointtemperaturesthatare higher(butnottoo muchhigher) thanthe
componentstobe separated. Forsuch a case,we needtoknow the normal boilingpointtemperaturesof
candidate solventsduringthe search.
Whenwe lookfor a solventforextraction,we needtocheckthe densitiesof candidatesolventstoensure the
twoliquidphasesformedduringextractionhave enoughdifferencesindensity. Forthe selectedsolvent,we
alsoneedto checkitsdensityagainstthe existingliquidphase sothatwe know whichliquidphaseisheavier.
Problem Statement
The pre-conditionof thisexample isthat3-methylhexaneisnow consideredapromisingcandidatesolventfor
separationof acetone andwater. The task is to determinewhetherthe densityof 3-methylhexane isdifferent
enoughfrom the density of water. We alsoneedto determinewhichof the twoliquidphasesformedmainlyby
these twocomponentsisheavier.

2
4.01. Create a new case inAspenHYSYS V8.0.
4.02. Create a componentlist. Inthe ComponentLists folderselectthe Addbuttonto add a new component
list.

3
4.03. Enter 3-methylhexane inthe Searchfor box. Aspen HYSYS shoulddisplaythe relevantsearchresults. If
the componentyouare lookingfordoesnotappear, you can alsouse the Filteror Search by drop-down
listfordifferentsearchcriteria. Clickthe < Addbuttonto add the componentto the componentlist.

4
4.04. To retrieve andviewthe pure componentproperty dataand, double-clickthe component 3-Mhexane.A
newwindowshouldappear.
4.05. Go to the Critical tab inthe newwindow.Youwill see alistof property datainthe Base Propertiesand
Critical Properties frames. Note thatthe Ideal Liquid Densityfor3-methylhexane is690.2 kg/m3
.

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4.06. In the navigationpane, gotothe Components| ComponentList -1 sheet. Enterwater inthe Search for
box and add the componenttothe componentlist.

6
4.07. Double-clickonthe component H2O. A new window shouldappear.

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4.08. Go to the Critical tab inthe newwindow. Youwill see alistof property datainthe Base Propertiesand
Critical Properties frames. Note thatthe Ideal Liquid DensityforWater is998.0 kg/m3
.
5. Conclusions
The densityof 3-methylhexane isaround690.2 kg/m3
,whichisclearlylessthan the density of water(998.0
kg/m3
).The liquidphase formedmainlyby3-methylhexane shouldbe lighterthanthe phase formedmainlyby
waterand, thus,the aqueousphase shouldbe atthe bottomand the otherliquidphase shouldbe atthe top.

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6. Copyright

1
Hypothetical Components and Petroleum Assays
with Aspen HYSYS® V8.0
 Create hypothetical componentsinAspenHYSYS
 Characterize apetroleumassay
2. Prerequisites
3. Background
AspenHYSYS allowsyoutocreate non-libraryorHypothetical components. These hypothetical componentscan
be pure components,definedmixtures,undefinedmixtures,orsolids. A wide selectionof estimationmethods
are providedforvariousHypogroupstoensure the bestrepresentationof behaviorfor the Hypothetical
componentinthe simulation.
In orderto accuratelymodel aprocesscontaininga crude oil,suchas a refineryoperation,the oil properties
mustbe defined. Itisnearlyimpossible todeterminethe exactcompositionof anoil assay,as there are far too
manycomponentsinthe mixture. Thisis a situation where hypothetical components are useful. Boilingpoint
measurementsof distillate fractionsof anassaycan be usedto characterize the oil properties.
Problem Statement
Create a hypothetical componentgroupinAspenHYSYSandcharacterize a petroleumassaytobe usedina
refinerysimulation.
4.01. Start a newsimulationin AspenHYSYSV8.0.
4.02. Create a componentlist. Inthe ComponentLists folderselectAdd. Change the Selectfieldto
Hypothetical and enterthe Initial and Final BoilingPoints for the hypothetical group shownbelow.
ClickGenerate Hypos whencomplete. Thiswillgenerateagroupof hypothetical componentswith
estimatedpropertiesbasedonthe specifiedboilingpointof eachcut.

2
4.03. ClickAdd All to add the entire hypothetical grouptothe componentlist.

3
propertypackage.
4.05. Enter the simulationenvironmentbyclickingthe Simulationbuttoninthe bottomleftof the screen.

4
4.06. Adda Material Stream to the flowsheetfromthe Model Palette. Doubleclickthe streamandgo to the
Compositionformunderthe Worksheettab.
4.07. You will notice thatthe mole fractionsof all the componentsare empty. If youwouldlike toassignan
oil assayto thisstreamgo to the PetroleumAssayform underthe Worksheettab. Selectthe option
Create New Assay On Stream.

5
4.08. Clickthe PetroleumAssay Specifications button. Thispage allowsyoutoenterassaydistillationdataor
importdata froma knownoil assay.

6
4.09. Clickthe Import From buttonand select AssayLibrary to importdata froma knownassayinthe HYSYS
assaylibrary.
4.10. Say,for example,thatwe wanttomodel a refineryprocessusingBachaqueroheavycrude from
Venezuela. Scroll downthe listof assaysandselect Bachaquero,Venezuela. Click ImportSelected
Assay.

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4.11. Aftera fewmomentsthe MacroCutData window will be filledwithdistillationcutdatafor Bachaquero
heavycrude.
4.12. Clickthe Calculate Assay buttonto assign mole fractionstothe hypothetical componentsdefinedfor
the stream. Exit the MacroCut Data window andview the Componentsformof the material stream.

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4.13. The compositionforthe streamisnow definedandwill model the propertiesof the selectedpetroleum
assaythrough the use of hypothetical components.
5. Conclusions
Thisexample demonstrateshowtocreate hypothetical componentsandhow toassigna petroleumassaytoa
streamin orderto model the assaypropertiesinasimulation.
6. Copyright
Copyright© 2012 by AspenTechnology,Inc.(“AspenTech”).All rightsreserved. Thiswork maynot be
RESPECT TO THIS WORK and assumesnoliabilityforanyerrors or omissions. Innoeventwill AspenTechbe
damagesarisingoutof the use of the informationcontainedin,orthe digital filessuppliedwithor foruse with,

Thermo-002H Revised:Nov6,2012
1
Flash Calculation in Aspen HYSYS® V8.0
1. Lesson Objective
 Learn howto model aFlash separatorand examine differentthermodynamicmodelstosee how
theycompare.
 FlashblocksinAspen HYSYS
2. Prerequisites
3. Problem
We wantto investigate Vapor-Liquidseparationatdifferent pressures,temperaturesandcompositions.Assume
youhave a feedwith anequimolarbinarymixture of ethanolandbenzeneat1 bar and 25°C. Examine the
followingflashconditionsusingthe heaterblockinAspenHYSYS.Use Vapor-Liquidasthe ValidPhase inthe
computation.
 Condition#1(P-VFlash):At 1 bar and a vapor fraction of 0.5, findthe equilibriumtemperature and
the heat duty.
 Condition#2(T-P Flash):At the temperature determined fromCondition#1 and a pressure of 1 bar,
verify thatthe flashmodel resultsina vapor fraction of 0.5 at equilibrium.
 Condition#3(T-V Flash):Atthe temperature of Condition#1,and a vaporfraction of 0.5, verifythat
the flashmodel resultsinan equilibriumpressure of 1bar.
 Condition#4(P-Q Flash):At1 bar and withthe heatduty determinedfrom Condition#1, verifythat
the temperature andvaporfractionare consistent withprevious conditions.
 Condition#5(T-Q Flash):At the temperature andheatdutydeterminedfromCondition#1,verify
that the pressure andvaporfraction are consistentwithpreviousconditions.
4. Aspen HYSYS Solution:
4.01. Start AspenHYSYS V8.0. SelectNewtostart a new simulation.
4.02. Create a componentlist. Inthe ComponentLists folderselectAdd. SelectEthanol and Benzene.

2
4.03. Create a fluid package. In the Fluid Packages folder select Add, and select NRTL as the property package.
4.04. Go to the simulationenvironment. Clickthe Simulationbuttoninthe bottomleftof the screen.
4.05. Place a Heater blockontothe flowsheetfromthe Model Palette.

3
4.06. Double click the Heaterto openthe propertywindow.Create an Inletstreamcalled FEED,an Outlet
streamcalled OUT, and an Energy streamcalled Q.
4.07. Specifyconditionsof FEEDstream. Go to the Worksheettaband entera Temperature of 25°C, a
Pressure of 1 bar (100 kPa),anda Molar flowof 1 kgmole/h. AlsoenterMole Fractionsof 0.5 foreach
componentonthe Compositionform.

4
4.08. Condition#1 Compute the temperature toget0.5 vapor fractionat 1 bar. In the Conditionsformunder
Worksheet,enteraVapour Fraction of 0.5 and a Pressure of 1 bar (100 kPa) for streamOUT. The
heaterwill automaticallysolve andyouwill see thatthe calculatedtemperature is 67.03°C.
4.09. Condition#2 Compute vaporfractionat 1 bar andat the temperature obtained inCondition#1. Clear
the fieldforVapour Fraction forstreamOUT, thenentera Pressure of 1 bar (100 kPa) and a
Temperature of 67.03°C. Inorder to be able to entera temperature,youmustfirstemptythe entry
fieldforVapourFraction. This isdone by clickingthe entryfieldand pressingdeleteonthe keyboard.
Once a Temperature isentered,the VapourFraction will solve.

5
4.10. Condition#3 Compute pressure atthe temperature obtainedinCondition#1with0.5 vapor fraction.
Delete the value inthe Pressure fieldandenteraVapour Fraction of 0.5. The pressure shouldsolve.

6
4.11. Condition#4 Compute temperature andvaporfraction at1 bar and usingthe heatduty obtainedin
Condition#1. Empty the fieldsforTemperature andVapour Fraction instreamOUT. InstreamOUT
entera Pressure of 1 bar. In streamQ, entera Heat Flow of 2.363e004 kJ/h. The Temperature of
67.03°C and Vapour Fraction of .500 are consistentwithCondition#1.
4.12. Condition#5 Compute pressure andvaporfractionat the temperature andheatdutyobtained in
Condition#1. In streamOUT, emptythe fieldforPressure. Entera Temperature of 67.03°C. The
Pressure and Vapor Fraction shouldbe the same as Condition#1.

7
5. Conclusion
You have gone through the five flashmethodswhichare mostcommoninAspenHYSYS.Here isa brief
summary.
Flash Method T (C) P (bar) V (-) Q (MJ/hr)
P-V Flash 67.03 1 0.5 23.63
T-P Flash 67.03 1 0.5099 23.98
T-V Flash 67.03 1 0.5 23.63
P-Q Flash (or P-H) 67.03 1 0.5 23.63
T-Q Flash (or T-H) 67.03 1 0.5 23.63 Specified Computed
FeedCondition:ETHANOL/BEZENE(Equimolarmixture) at1 bar and 25 Celsius.

8
6. Copyright
Copyright© 2012 by AspenTechnology,Inc.(“AspenTech”). All rightsreserved. Thisworkmaynot be
productnamesmentioned inthisdocumentationare trademarksorservice marksof theirrespective companies.

1
Steam Tables in Aspen HYSYS® V8.0
1. Objective
Learn howto access SteamTablesinAspen HYSYS,and how to interpretthe SteamTable data.
2. Prerequisites
3. Background
Aspen HYSYS offers 2typesof SteamTablesPropertiesMethods:
Property Method Name Models (Steam
Tables)
Note
ASME Steam ASME 1967
The ASME Steampropertymethodusesthe:
 1967 International Associationfor
Propertiesof WaterandSteam(IAPWS,
http://www.iapws.org) correlationsfor
thermodynamicproperties
STEAM-TA methodismade upof different
correlationscoveringdifferentregionsof the P-T
space.These correlationsdonotprovide
continuityatthe boundaries,whichcanleadto
convergence problemsandpredictwrongtrends.
NBS Steam NBS 1984
The NBS Steampropertymethodsusesthe:
 1984 International Associationfor
Propertiesof WaterandSteam(IAPWS,
http://www.iapws.org) correlationsfor
thermodynamicproperties
Use the NBS Steampropertymethod forpure
waterand steamwithtemperature rangesof
273.15 K to 2000 K. The maximumpressure is
over10000 bar.

2
4. Problem
UsingAspen HYSYS, we wantto calculate saturatedsteamproperties from100°C to 300°C. We wouldlike to
create a table thatdisplaysmassenthalpy,massentropy,pressure,anddensity.
Aspen HYSYS Solution:
4.01. Start AspenHYSYS V8.0. SelectNewto start a new simulation.
4.02. Create a componentlist. Inthe ComponentLists folder,selectAdd. AddWaterto the componentlist.
4.03. Create a fluidpackage. Inthe FluidPackages folder,selectAdd. SelectNBSSteamas the property
package.
4.04. Go to the simulationenvironment.

3
4.05. Adda material streamtothe flowsheetfromthe Model Palette.Double clickonthe streamtoopenthe
propertywindow. Rename thisstream STEAMandentera Mole Fraction of 1 forwater.
4.06. In the navigationpane,goto Stream Analysis andclick onthe dropdownarrow nextto Add and select
Property Table. In the SelectProcess Stream window thatappears,select STEAMandpress OK.
4.07. Next,double clickon PropertyTable-1to openthe propertywindow. UnderIndependentVariables
selectTemperature asVariable 1. Enter a Lower Bound of 100°C and an UpperBound of 300°C. Enter
100 for# of Increments. SelectVapourFraction for Variable 2 andselectState forMode. Entera value
of 1 for State Values. We are goingto be varyingthe temperature while holdingthe vapourfraction
constantat 1.

4
4.08. We mustnowdefine the dependentpropertiesthatwe are interestedinviewingresultsfor. Goto the
Dep. Prop formunderthe Design tab. SelectAdd. Here we will add Mass Enthalpy,Mass Entropy,
Pressure,andMass Density.

5
4.09. ClickCalculate to generate the propertytable. Resultscanbe viewedinthe Performance tabof the
propertytable window.

6
5. Conclusion
Aftercompletingthisexercise youshouldnow be familiarwithhow toaccessandinterpretthermodynamic
propertiesforsteamusingAspen HYSYS.
6. Copyright

1
Heat of Vaporization with Aspen HYSYS® V8.0
 Learn howto calculate heatof vaporizationusingthe heaterblockinAspen HYSYS
 Understandthe impactof heatof vaporizationondistillation
2. Prerequisites
3. Background
The drivingforce fordistillationisenergy. The mostenergyconsumingpartof a distillationcolumnis the
vaporizationof material inthe reboilertocause vaporto flow fromthe bottomof the columntothe topof the
column. Heatof vaporizationdeterminesthe amountof energyrequired. Therefore,itisimportanttoknowthe
heatof vaporizationof variousspeciesduringsolventselection. Witheverythingelse equal,we shouldselecta
componentwithlowerheatof vaporizationsothatwe can achieve the same degree of separationwithless
energy. Thisexample containsthree isolated heaterblocks. Each heaterblockis usedtocalculate the heatof
vaporizationforapure component.

2
4. Aspen HYSYS Solution:
4.02. Create a componentlist. Inthe ComponentLists folder,selectAdd. SelectWater,3-methylhexane,
and 1,1,2-trichloroethane.
4.03. Create a fluidpackage. Inthe FluidPackages folder,selectAdd. SelectUNIQUACasthe property
package and select RK as the Vapour Model.
4.04. Enter the simulationenvironment.

3
4.05. Addthree separate Heaterblocks to the flowsheet.
4.06. Double clickon E-100 to openthe propertywindow. Thisfirstheaterwill vaporize astreamof pure
water. Create an Inletstreamcalled Feed-Water,anOutletstreamcalled Water-Out,andanEnergy
streamcalled Q-Water.

4
4.07. Go to the Worksheettab. Specifythe feedstreamtobe at a Pressure of 100 kPa, a Vapour Fraction of
0, and witha Molar Flow of 1 kgmole/h. Inthe Compositionformunderthe Worksheettab,entera
Mole Fraction of 1 for Water inthe feedstream. Lastly,we mustspecifythe outletpressure andthe
outletvapourfraction. Enter 100 kPa for Pressure,and1 forVapour Fraction of the Water-Outstream.
The heatershouldsolve.Make note of the Heat Flow of the energystream Q-Water.
4.08. We will nowrepeatthisprocessforheaters E-101 and E-102. E-101 will vaporize 3-methylhexaneandE-
102 will vaporize 1,1,2-trichloroethane.
4.09. Double clickon E-101. Create an Inletstream called Feed-3MH,anOutletstreamcalled 3MH-Out,and
an Energy streamcalled Q-3MH.

5
4.10. In the Worksheettab,for the feedstreamentera Vapour Fraction of 0, a Molar Flowof 1 kgmole/h,
and a Pressure of 100 kPa. Inthe Compositionform, enteraMole Fraction of 1 for3-methylhexane in
the feedstream. Lastlyspecifythe outletconditionsof 100 kPa for Pressure anda Vapour Fraction of 1.
Make note of the Heat Flowfor the energystream.

6
4.11. Double click E-102. Create an Inlet streamcalled Feed-1,1,2,anOutletstreamcalled 1,1,2-Out, and an
Energy streamcalled Q-1,1,2.
4.12. In the Worksheettab,for the feedstreamentera Vapour Fraction of 0, a Molar Flowof 1 kgmole/h,
and a Pressure of 100 kPa. Inthe Compositionform, enteraMole Fraction of 1 for1,1,2-
trichloroethane inthe feedstream. Lastlyspecifythe outletconditionsof 100 kPa for Pressure anda
Vapour Fraction of 1. Note the Heat Flowof the energystream.

7
5. Conclusions
Althoughwaterhassmall molecularweight,itsheatof vaporizationislarge. Heatof vaporizationforwateris
about18% higherthanthat of 1,1,2-trichloroethaneandabout30% higherthanthat of 3-methylhexane. Of the
three options,3-methylhexane hastolowestheatof vaporizationandwould require the leastamountof energy
as a solventina distillation.
6. Copyright
AspenTech. ASPENTECHMAKESNO WARRANTYOR REPRESENTATION,EITHER EXPRESSEDOR IMPLIED, WITH

Therm-005H Revised:Nov6,2012
1
Simulation of Steam Engine with Aspen HYSYS® V8.0
 Learn howto simulate asteamengine withAspen HYSYS
 Learn how to specifypumps,heaters,coolers,expanders
2. Prerequisites
 Introductorythermodynamics
3. Background
A steamengine consistsof the followingsteps:
 Water ispumpedintoa boiler usingapump.
 Water isvaporizedin a boilerandbecomeshigh temperature and pressure steam.
 Steamflowsthrougha turbine anddoeswork. The pressure andtemperature godownduringthis
step. The steam isalsopartiallycondensed.
 The steam isfurthercooledtobe condensedcompletely. Then,itisfedtothe pumpmentionedin
the firststepto be re-used.
4.02. Create a componentlist. Inthe ComponentLists folder,selectAdd. AddWaterto the componentlist.

2
4.03. Create a fluidpackage. Inthe FluidPackages folder,selectAdd.SelectNBSSteam as the property
package.
4.04. Go to the simulationenvironmentbyclickingthe Simulationbuttoninthe bottomleftof the screen. In
the Home ribbon,selectEuroSIas the Unit Set.
4.05. Enter the simulationenvironment. Adda Heater,a Cooler,a Pump andan Expander as shown inthe
flowsheet.

3
4.06. Double clickthe pump(P-100) to openthe pumpspecificationwindow.Createan Inletstreamcalled
Liq-Water,anOutlet streamcalledToBoiler,andan Energy streamcalled Q-Pump.
4.07. In the Worksheettab,specifyanoutlet Pressure of 1.2 bar.

4
4.08. Double clickthe heater(E-100). SelectToBoileras the Inletstream, create an Outletstreamcalled
HPSteam (highpressure steam),andcreate an Energystream called Q-Heat.
4.09. In the Worksheettab,specifyanoutlet Pressure of 40 bar, and a Temperature of 460°C.

5
4.10. Double clickthe expander(K-100). SelectHPSteamasthe Inletstream, create an Outletstreamcalled
LPSteam, andcreate an Energystream called Q-Expand.

6
4.11. In the Worksheettab,specifyanoutlet Pressure of 1 bar.

7
4.12. Double clickthe cooler(E-101).Selectan Inlet streamof LPSteam, an Outletstreamof Liq-Water,and
create an Energy streamcalled Q-Cool.

8
4.13. In the Worksheettab,specifyanoutlet VapourFraction of 0 anda Pressure of 1 bar.
4.14. The flowsheetisnowreadytosolve. All thatislefttodo isto specifythe compositionandflowrate of a
streamwithinthe loop. Double clickonstream Liq-WaterandspecifyaMole Fraction of 1 for Water
and a Mass Flow if 10,000 kg/h.

9

10
4.15. The flowsheetshouldnowsolve.
5. Conclusions
The steam engine systemcanbe simulatedusingAspen HYSYS. Thisflowsheetclearlyshowswhereenergyis
beinginputtothe systemandwhere energyisbeingreleased.
6. Copyright

1
Illustration of Refrigeration with Aspen HYSYS® V8.0
 Learn howto specify compressors,heaters,andvalvesinAspen HYSYS
 Understand a refrigerationloop
2. Prerequisites
 Introductorythermodynamics
3. Background
In a typical refrigerationsystem,the refrigerantstartsatroom temperature andambientpressure. It is
compressed, whichincreasesthe refrigerant’stemperature andpressuresoitisa superheatedvapor. The
refrigerantiscooledbyairwitha fan sothat it isclose to room temperature. Atthispoint,itspressure remains
highand the refrigeranthasbeencondensedto a liquid. Then,the refrigerantisallowedtoexpandthrough an
expansionvalve. Itspressure decreasesabruptly,causingflashevaporation,whichreduces the refrigerant’s
temperature significantly. The verycoldrefrigerantcanthencool a fluidpassedacrossa heatexchanger(e.g.,
air inan air conditioner). Of course,foran ACunitto work,the airthat is usedto cool downthe super-heated
refrigerantmustbe airoutside of the room;the airthat is cooledbythe coldrefrigerantisthe air inside the
room.
Problem Statement
Determine the coolingcapacityof 300 kgmole/hof CFH2-CF3 whenallowedtoexpandfrom10bar to 1 bar.

2
4.02. Create a componentlist. Inthe ComponentLists folderselectAdd. Add1,1,1,2-tetrafluoroethane to
the componentlist.
4.03. Create a fluidpackage. Inthe FluidPackages folder,selectAdd.SelectNRTL as the propertypackage.
4.04. Move to the simulation environment. Clickthe Simulationbuttoninthe bottomleftof the screen. In
the Home ribbon,selectEuroSi as the UnitSet.
4.05. Adda Compressor,a Cooler,a Heater, and a Valve to the mainflowsheet.

3
4.06. Double clickonthe compressor(K-100). Create an Inletstreamcalled Vapor,an Outlet streamcalled
SuperHeat-Vapor,andan Energy streamcalled Q-Comp.

4
4.07. In the Worksheettab,specifyanoutlet Pressure of 10 bar.

5
4.08. Double clickthe Cooler(E-100). SelectSuperHeat-Vaporasthe Inletstream, create an Outlet stream
calledLiquid,andcreate an Energy streamcalled Q-Cool.
4.09. In the Worksheettab,specifyanoutlet Temperature of 30°C. Inthe Parametersform underthe Design
tab, entera Delta P of 0.

6
4.10. Double clickthe valve (VLV-100). Selectstream Liquidasthe Inlet streamandcreate an Outletstream
calledLowP.

7
4.11. In the Worksheettabspecifyanoutlet Pressure of 1 bar.

8
4.12. Double clickonthe heater(E-101). SelectstreamLowP as the Inletstream, selectstream Vaporas the
Outletstream,and create an Energy streamcalled Q-Heat.
4.13. In the Worksheettab,specifyanoutlet Temperature of 25°C. Inthe Parametersform underthe Design
tab, specifyaDelta P of 0.

9
We mustnowspecifythe molarflowrate andcompositionof the refrigerant. Double clickanystream,
for example stream Liquid. EnteraMolar Flow of 300 kgmole/h. In the Compositionformspecifya
Mole Fraction of 1 for the refrigerant.

10
4.14. The flowsheetwill nowsolve.

11
4.15. Checkresults. Toviewthe coolingcapacityof thisrefrigerationloop,doubleclickenergystream Q-Heat.
The stream isremoving 1.26e006 kcal/h, or approximately350kcal/sec.
5. Conclusions
Refrigerationisaprocesswhere heatmovesfromacolderlocationtoa hotterone usingexternal work(e.g.,a
compressor). We knowthatvaporizationof a liquidtakesheat. If there isnoexternal heatavailable,the heat
will come fromthe liquiditself byreducingitsowntemperature.
6. Copyright
liable toyoufordamages,includinganylossof profits,lostsavings, orotherincidental orconsequential

1
Maximum Fill up in Propane Tanks with Aspen HYSYS® V8.0
Using a Spreadsheet
 How to calculate the maximumliquidlevel inpropane tanks
 How to accessstreamvariablesinAspen HYSYS
 How to configure aheaterblock
 How to use the Spreadsheettool toperformcustomizedcalculations
2. Prerequisites
3. Background
Whena propane tank isfilledat25°C, we needtoleave enoughvolumefor liquidpropaneexpansiondue toan
increase intemperature. The hottestweathereverrecordedisabout58°C. In real life practices,propane tanks
are onlyfilledupto80-85% of the tank volume. Why? We know that propane expandswhenitisheatedup.
However,why80-85%?
We can answerthisquestionbyusingasimple flashcalculationinAspen HYSYS.
Problem Statement
Propane tanksare filledat25°C withliquefiedpropane. These tankswill be storedandusedinanenvironment
at 1 bar and ambienttemperature. Howmuch,intermsof volume %, caneach tankbe filledup to?

2
4.02. Create a componentlist. Inthe ComponentLists folderselectAdd.AddPropane to the componentlist.
4.03. Create a fluidpackage. Inthe FluidPackagers folder,selectAdd.SelectPeng-Robinsonasthe property
package.
4.05. Adda Heaterto the flowsheet.

3
4.06. Double clickonthe heater(E-100). Create an Inletstream, an Outletstream, and an Energy stream,
named1, 2, andQ, respectively.

4
4.07. Define feedstream. Goto the Worksheettab. For the feedstream, entera Vapour Fraction of 1, a
Temperature of 25°C, and a Molar Flowof 1 kgmole/h. Inthe Compositionform, enter1 forMole
Fraction of propane.

5
4.08. Specify outletconditions. Forthe outletstream, entera Vapour Fraction of 0, and a Temperature of
58°C. The heatershouldsolve.
4.09. Adda Spreadsheettothe flowsheettocalculate the maximumpercenttofill the propane tanktoallow
for expansionwhenheated.

6
4.10. Double clickthe spreadsheet(SPRDSHT-1). Go to the Spreadsheettaband enterthe followingincells
A1, A2, andA3.

7
4.11. Nowwe will linkflowsheetvariablestothe spreadsheet. Rightclickoncell B1 and selectImport
Variable.Make the followingselectionstoimportthe MolarDensity of stream1. Click OK when
complete.
4.12. Rightclickon cell B2 andselectImport Variable to importthe Molar Densityof stream2. Make the
followingselectionsandclick OK.

8
4.13. The spreadsheetshouldnowlooklike the following.
4.14. Next,clickcell B3 andenter“=(B2/B1)*100”. Thisdividesthe molardensityat58°C bythe molardensity
at 25°C. The resultingnumberisthe percentage thatapropane tank shouldbe filledat25°C to allowfor
thermal expansionuptoa temperature of 58°C.
4.15. The maximumfill %of propane at 25°C is87.86%, as seeninthe spreadsheet.

9
5. Conclusions
The calculation shows that the maximum fill up is 87.8% if the ambient temperature doesn’t exceed 58 °C. To
accommodate special cases, typically, propane tanks are filled up to 80-85%. After completing this exercise you
shouldbe familiarwithhowtocreate a spreadsheettoperformcustomcalculations.
It is important to note that, in real life, the content in a filled propane tank is typically a mixture instead of pure
propane. In addition to propane, the mixture also has a few other light components such as methane and
ethane. Therefore, to carry out calculations for a real project, we need to know the compositions of the mixture
we are dealingwith.
6. Copyright

1
Generate PT Envelope with Aspen HYSYS® V8.0
 Learn howto generate PTenvelopesinAspen HYSYS
2. Prerequisites
 Aspen HSYSY V8.0
3. Background
It isveryimportantto knowthe phase conditionsof amixture ata giventemperatureandpressure. For
example,the phase conditionsof afluidina heatexchangerhave animpacton the heat transferrate.
Formationof bubbles(vaporphase) ininletstreamscanalsobe verydamagingtopumps. The phase conditions
of a fluidina pipe canimpact pipeline calculations.
The PT envelope foragivenmixture providesacomplete picture of phase conditionsforagivenmixture.
The examplespresentedare solely intendedtoillustrate specificconceptsand principles. Theymay not
4.01. Start AspenHYSYS V8.0 andstart a new simulation.
4.02. Create a componentlist. Inthe ComponentLists folderselectAdd. AddEthane and n-Pentane tothe
componentlist.

2
propertypackage.
4.04. Go to the simulationenvironmentbyclickingthe Simulationbuttoninthe bottomleftof the screen.
4.05. Adda Material Stream to the flowsheet. Tocreate a PT Envelope we mustperforma StreamAnalysis,
and inorderto performa StreamAnalysiswe needamaterial stream.

3
4.06. Double clickthe material stream(1). Entera Molar Flow of 100 kg/h. In the Compositionformenter
Mass Fractions of 0.5 foreach component.
4.07. Rightclickon the streamand select Create Stream Analysis| Envelope.

4
4.08. In the Envelope window,gotothe Performance tab. Here you will see aPT Envelope. Note thatyou
can change the Envelope type usingthe radiobuttonsinthe bottomrightcorner of the window. Onthe
graph,the blue line representsthe dew pointandthe redline representsthe bubble point. The area
betweenthe lines representsthe 2-phase region.

5
5. Conclusions
Withthe PT envelope of amixture,we candetermine itsphase conditionsforagiventemperature andpressure.
6. Copyright

1
Retrograde Behavior Illustrated with Aspen HYSYS® V8.0
 Observe retrograde behavior
2. Prerequisites
 Completionof teachingmodule Thermo-013
3. Background
For a mixture,the amountof liquid(liquidfraction) increasesas pressure increasesatconstanttemperature.
However,inthe retrograde regionnearthe critical region,we maysee some interestingbehavior—vapor
fractionincreasesaspressure increases(atconstanttemperature).
Many mixtureshave retrograde behavior nearthe critical region. Inthisexample,we will examine the
retrograde behaviorusingabinary mixture of ethane and pentane.
Problem Statement
Retrograde behaviorcanbe observedinthe mixture of ethane andpentane.InAspen HYSYS,use PTEnvelope to
determine the critical regionof the mixture.Then,use aPropertyTable toexamine the retrograde behaviornear
the critical region.

2
4.01. Openthe file titled Thermo-14H_Retrograde_Behavrior_Start.hsc. Thisisidentical tothe file thatwas
createdinlessonThermo-013H_PT_Envelope.
4.02. In the PT Envelope that appearsinthe Performance tab of the Envelope window,notice thatthere isa
regionnearthe critical pointwhere the vaporfractionwill increase aspressure increaseswhile
temperature isheldconstant.

3
4.03. We can demonstrate thisbehaviorbycreatingapropertytable inHYSYS. In the Stream Analysisfolder
inthe NavigationPane,click the dropdownarrow nextto Add and selectPropertyTable. Selectstream
1 and click OK.

4
4.04. Double click PropertyTable-1. SelectTemperature forVariable 1 andselectState forMode. Entera
State value of 115°C. SelectPressure forVariable 2 and Incremental forMode. Entera Lower Bound
of 60 bar, an UpperBound of 69 bar, and a # of Incrementsof 20.
4.05. In the Dep. Prop formunderthe Design tab click Add. SelectVapourFraction and click OK.

5
4.06. ClickCalculate.Once complete,gotothe Performance tab. Here youcan view the resultsineithertable
or plotform. Go to Plotsand selectViewPlot.
4.07. From the plotyoucan clearlysee the regionwhere increasingthe pressure will cause the vapour
fractionto increase.
5. Conclusions
For the binarymixture of ethane andpentane (50% eachon massbasis),we observedthatvaporfraction
increasesfrom0.701457 to 1 as pressure increasesfrom65.22 bar to 66.78 bar, whichisa retrograde behavior.
Thisretrograde behaviorcanbe a source of multiple solutionsto process simulation.
6. Copyright
RESPECT TO THIS WORK and assumesnoliabilityforany errorsor omissions. Innoeventwill AspenTechbe

6

Thermo-019H Revised:Nov 7,2012
1
Remove Hydrogen from Methane, Ethylene and Ethane
with Aspen HYSYS® V8.0
 Learn howto remove bulkof hydrogenusinga cooleranda vapor liquidseparator
 Learn howto use adjustblockand spreadsheets
2. Prerequisites
 Introductiontovapor-liquidequilibrium
3. Background
In an ethyleneplant, we have afeedstreamcontaininghydrogen,methane,ethylene,andethane. Before this
streamcan be fedto the demethanizer, hydrogenmustbe removedsothe volumetricflow isless,which
decreasesthe requiredsizeforthe demethanizercolumn. Because hydrogen hasamuch highervaporpressure
than the othercomponents,one ormore flashdrumscan be usedfor hydrogenremoval.
Problem Statement
The feedstreamisa combinationof 6,306 lb/hrof hydrogen,29,458 lb/hrof methane,26,049 lb/hrof ethylene,
and 5,671 lb/hrof ethane.The mole fractionof hydrogeninthe feedstreamisgreaterthan0.51, indicatinga
large volume of hydrogeninthe feedstream. There are twogoalsforthissectionof the process:
 Afterbulkof hydrogen isremoved,the streamcontainslessthan0.02 mole fractionof hydrogen
 Loss of ethylene tothe hydrogen streamshouldbe lessthan1%

2
4.02. Create a componentlist. Inthe ComponentLists folderselectAdd. AddHydrogen, Methane,Ethylene,
and Ethane to the componentlist.
propertypackage.
4.04. Go to the simulationenvironment. Clickthe Simulationbuttoninthe bottomleftcornerof the screen.
4.05. Adda Coolerblockto the flowsheetfromthe Model Palette.

3
4.06. Double clickthe cooler(E-100). Create an Inlet streamcalled Feed,anOutletstreamcalled ToSep,and
an Energy streamcalled Q-Cool.

4
4.07. In the Parameters form,entera Delta P of 0, anda Duty of 0 kcal/h. We will create anadjustblockto
vary the dutyto reach the desired specifications.

5
4.08. Define feedstream. Goto the Worksheettab. Entera Temperature of -90°F (-67.78°C),and a Pressure
of 475 psia (32.75 bar).
4.09. Define composition. Goto the Compositionformand enterthe following MassFlowratesin kg/h.

6
4.10. Adda Separator to the flowsheetfromthe Model Palette.
4.11. Double clickthe separator(V-100). SelectstreamToSepas the Inletstream, andcreate Outletstreams
calledVapand Liq.

7
4.12. Go to the Worksheettabto viewthe separationresults. Youcan see thatthe liquidstreamhasa
flowrate of 0. We mustnowadd an adjustblockand a spreadsheettofindthe coolerduty requiredto
limitthe lossof ethylenetothe vaporstreamto lessthan1%.

8
4.13. Adda Spreadsheettothe flowsheetfromthe Model Palette.
4.14. Double clickonthe spreadsheet(SPRDSHT-1). Inthe Spreadsheettabenter“Ethylene flowin Feed”in
cell A1, and “Ethylene flowin Liq stream” incell A2. Right clickoncell B1 and selectImportVariable.
Selectthe MasterComp Molar Flow (Ethylene) inthe Feedstream. Rightclickcell B2 and selectImport
Variable. Selectthe Master CompMolar Flow (Ethylene) inthe Liqstream.

9
4.15. Enter the text“FractionEthylene Lost” in cell A3. Incell B3 enterthe followingformula: =(B1-B2)/B1.
4.16. You can see that rightnowwe are losing100% of the Ethylene to the vapor stream. We will nowaddan
adjustblockto vary the coolerdutyinorder to limitthe fractionlosttounder0.01. Addan Adjust block
to the flowsheetfromthe Model Palette.

10
4.17. Double clickonthe adjustblock(ADJ-1). Specifythe AdjustedVariable tobe the Duty of coolerblock E-
100. Specifythe TargetVariable to be cell B3 of SPRDSHT-1. Entera SpecifiedTargetValue of 0.01.

11
4.18. In the Parameters tab entera StepSize of 1e+005 kcal/h and change the Maximum Iterationsto 100.
ClickStart to begincalculations.

12
4.19. The fractionof ethylenelostinthe vaporstreamwill now be lessthan1%. We must alsomake sure that
the Mole Fraction of Hydrogen inthe liquidstreamislessthan0.02. Double clickthe Liq streamand go
to the Compositionformunderthe Worksheettab.
4.20. The Mole Fraction of hydrogeninthe liquidstreamis 0.0172, whichislessthanthe specifiedvalue of
0.02.

13
5. Conclusions
The vapor pressure of hydrogenis muchhigher(6,600 timeshigherthanmethane at -150 °C) than the vapor
pressuresof the othercomponents inthe feedstream. We used the adjustblockanda spreadsheetto
determine agoodvalue forthe heatdutyof the coolerblock to remove the bulkof hydrogenfromthe feed
streamthrougha separatorblock.
6. Copyright

1
Use of a Decanter to Recover Solvent and Cross Distillation
Boundaries with Aspen HYSYS® V8.0
 Use a 3 phase separatorto recoversolvent
2. Prerequisites
 Introductiontoliquid-liquidequilibrium
3. Background
In an anhydrousethanol productionplant,cyclohexane isusedasanentrainerduringseparationtobreakthe
ethanol-waterazeotrope. The streamfromthe topof the firstdistillationcolumnistypicallyamixture witha
compositionthatisveryclose to the ternary azeotrope. Since cyclohexane andwaterare notmiscible,a
decantercan be usedto separate cyclohexanefromthe ethanol andwater. The secondrole of thisliquid-liquid
separationistocross distillationboundaries. One of the twooutletstreamsfromthe decanterisrecovered
solvent. The otherstreamhasa compositioninthe ethanol-richdistillationregionandisfedtothe second
column.
4. Use of a Decanter for solventrecovery
Problem Statement
A 100 kmol/hrfeedstreamthatis35 mol-%ethanol,6mol-% water,and59 mol-% cyclohexane isfedtoa
decanter. Determine the compositionsof the twooutletstreamsfromthe decanterandtheirflowrates.

2
4.01. Start AspenHYSYS V8.0 andcreate a new simulation.
4.02. Create a componentlist. Inthe ComponentLists folderselectAdd.AddEthanol,Water, and
Cyclohexane tothe componentlist.
4.03. Define propertypackage. Inthe FluidPackagesfolderselectAdd. SelectUNIQUACasthe property
package. In the Activity Model Specifications grid,selectRKforVapour Model.
4.05. Adda 3-Phase Separator to the flowsheetfromthe Model Palette.

3
4.06. Double clickthe 3 phase separatorvessel (V-100). Create an Inletstreamcalled Feed,andthree Outlets
calledVapor,Liquid1, andLiquid2.

4
4.07. Define feedstream. Goto the Worksheettab. Entera Temperature of 25°C, a Pressure of 1 bar, and a
Molar Flow of 100 kgmole/h.
4.08. In the CompositionformenterMole Fractions of 0.35 forethanol,0.06 forwater, and 0.59 for
cyclohexane. The separatorshouldsolve whencompositionsare complete.

5
4.09. Checkresults. Youcan see that the feedstreamwasseparatedintotwoseparate liquidstreams
because of a differenceindensitybetweenthe twoliquidphases. Stream Liquid1hasflowrate of 54.6
kgmole/h,while the heavierstream Liquid2hasa flowrate of 45.4 kgmole/h.

6
4.10. Checkstreamcomposition. StreamLiquid1isenrichedincyclohexane whilestreamLiquid2isenriched
inethanol.

7
5. Conclusions
A Decantercan be usedto concentrate cyclohexanefrom59% to 78% so it can be recycled orrepurposed.The
otheroutlet(Liquid2) hasacompositioninadifferentdistillationregionfromthe Feedstream, providinga
productthat crossesdistillation boundaries.Thisservesasthe decanter’ssecond role mentionedinthe
backgroundsection.
6. Copyright
thiswork. This workand itscontentsare providedfor educational purposesonly.

Dist-001H Revised:Nov7,2012
1
Distillation of Close Boiling Components with Aspen HYSYS® V8.0
 Distillation columnmodeling
 Columnprofiles
 Customstreamresults
 Material balance across distillationcolumn
2. Prerequisites
 AspenHYSYS V8.0
 Experience insertingblocksandconnectingstreamsin HYSYS
 Introductiontovaporliquidequilibrium
3. Background
Ethylene isanimportantmonomer,andismade fromethane. The conversionof the reactionisnotperfect,so
the ethylene mustbe separatedfromthe system. Ethane andethyleneare molecularlysimilar,andsoare
difficulttoseparate. The difficultyof the separationiscompoundedbythe factthat polymerproduction
requiresextremelypure feedstocks.
Problem: A stream containing 68.5wt% ethylene with a total flowrate of 7.3 million lb/day is fed into a
distillation column consisting of 125 stages. It is desired to produce a distillate product stream containing a
minimum of 99.96 wt% ethylene with a total flowrate of 5 million lb/day. It is also desired that the bottoms
productcontainsno more than 0.10wt% ethylene.Determineif thisseparationisfeasible.

2
Assumptions:
- 100% tray efficiency
- Total condenser
- 300 psigcolumnoperatingpressure
- A refrigerantutilitystreamcapable of condensingthe ethylene mixture(notincludedin model)
- Feedmixture isat350 psig andis a vapor
- 125 stages
- Feedenters the columnatstage 90
- Peng-Robinsonequationof state
AspenHYSYS Solution:
4.01. Start AspenHYSYS V8. SelectNewto start a new simulation.
4.02. Create a ComponentList. In the Propertiesenvironment,selectthe ComponentListsfolderinthe
navigationpane andclick Add to adda new HYSYS componentlist. In ComponentList– 1 addEthane
and Ethylene tothe selectedcomponentslist. Youmayneedtouse the searchfunctionbytypingin
ethene andpressingentertofindthe componentethylene.

3
4.03. Create a Fluid Package. Click on the Fluid Packages folder in the navigation pane and select Add to add a
new HYSYS fluid package. Select Peng-Robinson as the property package. The Peng-Robinson equation
of state istypicallyusedtomodel systemscontaininghydrocarbonsathighpressures.
4.04. You are now ready to enter the simulation environment and construct the flowsheet. Go to the
simulation environment by clicking the Simulation button at the bottom left of the screen. On the main
flowsheetinsertaDistillationColumnSub-Flowsheetfromthe Model Palette underthe Columnstab.

4
4.05. Double click on the Distillation unit on the main flowsheet, or go to UnitOps | T-100 in the navigation
pane. The Distillation Column Input Expert window will appear. Here we will create the feed and
product streams, as well as define the operating conditions of the column. On the first page, enter 125
for # Stages and define the feedandproductstreamsas shownbelow.

5
4.06. Click Next and page 2 will appear. This page allows you to configure the reboiler. Select Regular Hysys
reboilerforReboilerType Selection,andselectthe Once-throughradiobutton. Click Next.
4.07. This next page allows you to input the pressure and pressure drop in the condenser and reboiler. Enter
a Condenser Pressure and Reboiler Pressure of 300 psig (2170 kPa). This indicates that there is no
pressure dropthroughthe column,whichisacceptable forthissimplifiedexample.
4.08. Click Next. This page (page 4 of 5) allows you to enter optional temperature estimates for the
condenser, top stage, and reboiler. In this case we will leave these fields blank. Click Next. The final
page allows you enter a liquid distillate rate or a reflux ratio. From our problem statement, we know
that distillate rate will be 5 million lb/day of ethylene. Select Mass for Flow Basis and enter 5000000
lb/day (94498.4 kg/h) for LiquidRate. SelectDone to enterthe columnpropertywindow.
4.09. We must first define the feed stream going into the column. In the Column property window, go to the
Worksheet tab. On the Conditions form, enter a pressure of 350 psig (2514 kPa), a Vapour fraction of
1, and a Mass Flow of 7.3e+06 lb/day (1.380e+005 kg/h) for the Feed@COL1 stream. Go to the
Compositions sheet in the Worksheet tab. Here we will define the composition of the feed stream.
Type a number into the Feed composition grid for Ethane to open the Input Composition for Stream
window. Select the Mass Fractions radio button, enter 0.315 for Ethane and 0.685 for Ethylene. Click
OK. The feed stream on the main flowsheet should turn blue, indicating that all required input has been

6
entered and that it has solved for all properties. If you open the Feed stream property window you will
see a greenstatusbar sayingOK at the bottom.

7
4.10. Now we must enter design specs to reach the desired product compositions as provided in the problem
statement. In the Column property window, go to Design | Specs. Our two design specifications for this
simulation will be distillate rate and mass fraction of ethylene in the bottoms stream. In the column
specifications form there should already be a Distillate Rate spec that was created from the column
input expert. Make sure that the distillate specification value is correct (9.450e+004 kg/h) and that the
specis checkedasactive.
4.11. In the Column Specifications form, click Add and select a Column Component Fraction specification. In
the Comp Frac Spec window select the Stream radio button for Target Type. Enter Ethane@COL1 for
Draw, Mass Fraction for Basis, and 9.0e-004 for Spec Value. Select Ethylene for Components. Close
thisformwhenall information isentered.

8
4.12. Make sure that this spec (Comp Fraction) is checked as Active in the Specification Details area. You will
notice that after activating the Comp Fraction spec, the Degrees of Freedom changes to -1. This means
that the problem is over specified. To fix this, simply deactivate one of the column specifications, in this
case the Reflux Ratio. Once the reflux ratio design spec is deactivated, the column should solve. You will
notice thatthe statusbar at the bottomof the sheetwill turngreenandsay Converged.

9
4.13. Check results. In the Column property window, go to the Performance tab. On the Summary sheet you
can see the flowrates and compositions of the feed and product streams. You can see that both
specificationsdescribedinthe problemstatementare met.

10
4.14. In the Column Profiles sheet you can view the calculated reflux ratio, boilup ratio, as well as material
and energyprofilesthroughthe column.
4.15. On the Plots sheet you can create plots such as temperature and composition along the column, as
shownbelow.

11

12
4.16. Finally, on the Cond./Reboiler sheet you can view the calculated operating conditions for both the
condenserandreboiler.
5. Conclusions
The 125 stage column was able to exceed the specification of 99.96wt% ethylene at 5 million lb/day, as well as
the bottoms having less than 0.10wt% ethylene. It could then be concluded that this column is capable of
completing the desired separation. Aspen HYSYS allows engineers to model existing equipment and see if it is
possible torepurpose it or,otherwise, designnew equipmentthatwould meetvery specificcriteria.
6. Copyright

1
Pressure Swing Distillation with Aspen HYSYS® V8.0
 Configure distillationcolumnsinAspenHYSYS
 Learn to use pressure swingtoovercome azeotropicmixture
2. Prerequisites
 Workingknowledgeof vapor-liquidequilibrium anddistillation
3. Background
Basics on Azeotropic Distillation
An azeotrope occurs when the liquid and vapor mole fractions of each component are the same. On a y-x plot,
an azeotrope is shown by a line which passes through the x = y line. Azeotropes present challenges to
separationprocessesandneedtobe accountedforinprocessdesignandoperation.

2
No further enrichment can occur in either phase when the system reaches the azeotrope constraint because the
driving force is eliminated. A mixture will separate towards a pure component and the azeotropic mixture. The
component whichis purified depends onwhich side of the crossover the initial mixture is. To purify the minority
component, you must first cross the azeotrope. This can be done by adding an entrainer, another chemical
which breaks the azeotrope. This creates the need for additional separation and usually material recycle with a
purge stream. Alternatively, the composition of the azeotrope is dependent on pressure, which can be
exploitedtogetthe mixture acrossthe azeotrope. Thisiscalledpressure swingdistillation.
Ethanol and water form an azeotrope at approximately 95.5mol-% ethanol at 1 atm. This is a low-boiling point
(or positive) azeotrope. The boiling point of the mixture is lower than either of the pure components, so the
azeotropic mixture exit from the top of the column regardless of which compound is being enriched in the
bottoms.
The examples presented are solely intended to illustrate specific concepts and principles. They may not
4. Problem Statement
A feed of 24,000 kg/h of 20mol-% ethanol and 80 mol-% water must be separated. The required product stream
is 99 mol-%ethanol at a flowrate of at least 7,500 kg/h. This separation will be achieved by using pressure swing
distillation.
We begin by creating a technically feasible design for a two-column separation train. We will report for each
column: operating pressure, number of stages, reflux ratio, and the purity and recovery specifications. Also
report a stream table with the flowrates and compositions of relevant streams. Material recycle will be
necessary to achieve these results. We will use an operating pressure of 0.1 bar for the first column, and an
operatingpressure of 20 bar for the secondcolumn.
4.02. Create a componentlist. Inthe ComponentLists folderselectAdd. Addethanol andwaterto the
componentlist.

3
4.03. Define propertypackage. Inthe FluidPackagesfolderselectAdd. SelectNRTLas the propertypackage.
SelectRK as the Vapour Model. The non-random, twoliquid(NRTL) model workswell forverynonideal
liquidsystemswhichisimportantbecause of the hydrogenbondingpresent. The Redlich-Kwong
equationmodel worksmuchbetterathighpressuresthanthe ideal gasassumptioninthe vapourphase.
4.04. Go to the simulationenvironmentbyclickingthe Simulationbuttoninthe bottomleftof the screen.
4.05. Adda DistillationColumnSub-Flowsheettothe flowsheetfromthe Model Palette.

4
4.06. Double click the column (T-100). This will open the Distillation Column Input Expert window. Enter the
followinginformationandclick Nextwhencomplete.

5
4.07. On the second page of the input expert leave the default selections for a Once-through, Regular Hysys
reboilerandclick Next.
4.08. On page 3 of the input expert enter Condenser and Reboiler Pressures of 0.1 bar. Click Next when
complete.
4.09. On page 4, leave all fields for temperature estimates blank. Click Next to continue. On page 5 of the
inputexpert,againleave all fieldsblankandclick Done toconfigure the column.
4.10. We will now define the feed stream. Double click on the Feed stream. In the Worksheet tab enter a
Temperature of 65°C, a Pressure of 1.2 bar, anda Mass Flowof 24,000 kg/h.

6
4.11. Go to the Compositionformunderthe Worksheettabto define the compositionof the feedstream.
Enter Mole Fractions of 0.2 for ethanol and 0.8 forwater. Whencomplete,the feedstreamshouldbe
fullydefinedandwillsolve.
4.12. Double clickthe column(T-100) to finishspecifyingthe operatingconditions. Goto the Specs form
underthe Designtab. First,we wouldlike torecover99% of ethanol fromthe feedstream. Todo this
we will clickthe Addbuttonand select ColumnComponentRecovery. SelectstreamD1 as the Draw,
entera Spec Value of 0.99, andselectEthanol as the Component.

7
4.13. Second,we wouldlike the distillatestream(D1) to have a mole fractionof 0.90 for ethanol. The
azeotrope preventsusfromthe reachingthe desiredproductpurityof 99% witha single column,butwe
wouldstill wantthe distillate from the firstcolumntobe verypure while losingaslittle producttothe
bottomsstreamas possible. Click Addand selectColumnCompFraction. SelectStreamfor Target
Type, D1 for Draw, 0.90 for Spec Value,andEthanol for Component.

8
4.14. Go to the SpecsSummary form underthe Designtab. Make sure that the onlyspecificationsmarkedas
active are CompRecovery and CompFraction. The columnwill attempttosolve once these specsare
active.
4.15. If the solverfailstoconverge,we mayhave toadd some parameterestimates. Forexample,we can
provide anestimate forthe distillate streamflowrate basedona simple massbalance. We knowthat
the feedcontainsapproximately 200 kgmole/hof ethanol. We alsoknow that we wantto recover99%
of ethanol withanethanol mole fractionof 0.9in the distillate. We canthenprovide anestimate of 220
kgmole/hrforthe distillate stream. Inthe SpecsSummary grid,enter220 kgmole/h forDistillate Rate
whichwill serve asanestimate aslongas it isnot an active specification. Click Runwhencomplete. The
columnshouldnowconverge. Alsonote thatthe bottomsstreamisover99% water,whichmeansthat
we are throwingawayverylittle ethanol. A pure waterstreamisalsodesirable becausewe cannow
repurpose ordispose of thisstreamwithminimal furtherprocessing.

9
4.16. We are now readyto constructthe secondcolumn, whichwilloperate onthe otherside of the
azeotrope ata pressure of 20 bar. We firstneedtoinserta pumpto increase the pressure of the
distillatestreamleavingthe firstcolumn. Adda pump to the flowsheetfromthe Model Palette.

10
4.17. Double click the pump (P-100). Select stream D1 as the Inlet, create an Outlet stream called Feed2, and
create an Energy streamcalled Q-Pump.
4.18. In the Worksheet tab, enter a Pressure of 20 bar (operating pressure of the second column) for stream
Feed2. The pumpshouldsolve.

11
4.19. Nextwe will insertthe second DistillationColumnSub-Flowsheettothe flowsheet,afterthe pump.
4.20. Double click the second column (T-101). This will open the Distillation Column Input Expert. On the
firstpage,enterthe followinginformationandclick Nextwhencomplete.
4.21. On page 2 of the input expert, leave the default selections for a Once-through, Regular Hysys reboiler.
ClickNext.
4.22. On page 3 of the input expert, enter Condenser and Reboiler Pressures of 20 bar. Click Next when
complete.

12
4.23. On page 4 leave all fields for temperature estimates blank. Click Next. On the final page, also leave all
fieldsblank. Click Done to configure the column.
4.24. We must now enter the operating specifications for the column. In the column window for T-101 go to
the Specs form under the Design tab. Add a column specification for the mole fraction of ethanol in the
bottoms stream. Click Add and select Column Component Fraction. Select Stream for Target Type,
Ethanol for Draw, 0.99 for SpecValue,and Ethanol forComponent.

13
4.25. We will now add a specification for the mole recovery of ethanol in the bottoms stream. In the Specs
Summary form under the Design tab, double click the specification for Btms Prod Rate. We know that
approximately 203 kgmole/h of ethanol are entering the process in the original feed stream. Since we
are recovering 99% of the ethanol in the first column, we expect the final product stream to have a
flowrate of approximately 200kgmole/h.
4.26. In the Specs Summary form, make sure that the only active specifications are Btms Prod Rate and Comp
Fraction. The columnwill attempt to solve, but you should find that it will not be able to converge. This
isbecause we needtoadd a recycle streamto the flowsheet.

14
4.27. Double click on the first column (T-100) and add a second Inlet Stream called Recycle. This stream will
enteronthe same stage as the Feedstream(stage 25).
4.28. We will define the recycle stream with a guess of what the actual recycle stream will consist of. We will
use this “dummy” recycle stream to allow both columns to converge, and then we will add a recycle
block to find the actual recycle stream conditions. Double click the Recycle stream on the flowsheet. In
the Worksheet tab enter a Vapour Fraction of 0, a Pressure of 1.2 bar, and a Molar Flow of 400
kgmole/h. In the Composition form enter Mole Fractions of 0.9 for ethanol, and 0.1 for water. Again,
these values are just guesses that will be used to converge both columns. The actual values for the
recycle stream will be determined later through the use of a recycle block. Make sure that you specify
Recycle in its own window, rather than in the Worksheet tab of Column T-100, as this will cause a
consistencyerrordue tooverspecificationwhenyoutrytocomplete the recycle loop.

15
4.29. Once the recycle stream is fully specified, double click on each column and click Run to converge the
columns. Bothcolumnsshouldnowsuccessfullyconverge.
4.30. Now we can close the recycle loop to determine the actual values for the Recycle stream. First we must
lower the pressure of stream D2 through the use of a valve. Add a Valve to the flowsheet from the
Model Palette.

16
4.31. Double clickonthe valve (VLV-100). SelectstreamD2 as the Inletand create an OutletcalledRec.
4.32. Go to the Worksheettaband specifyanoutlet Pressure of 1.2 bar. The valve shouldsolve.

17
4.33. We will nowadda Recycle blockto the flowsheetfromthe Model Palette.

18
4.34. Double click on the recycle block (RCY-1). Select stream Rec as the Inlet and stream Recycle as the
Outlet. The recycle blockshouldautomaticallysolve.

19
4.35. Go to the Worksheet tab to view recycle convergence results. The two streams should be equal to each
otherwithinacertaintolerance.
4.36. If you are not satisfied with the recycle convergence, go to the Parameters tab and lower the
sensitivities. For example if we change the sensitivity value to 1 for Flow and Composition we get the
followingresults.

20
4.37. The flowsheet is now complete. Further analysis can be performed to optimize the column size, feed
location,andenergyrequirements,butthatanalysisisnotcoveredinthislesson.

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