清华大学《化工系统工程基础》columnstart-u

AspenPlusTrainingColumnStart-up,清华大学邱彤,AspenPlusDynamicsHelpColumnStart-up,2020/5/1,2,ColumnStart-up,2020/5/1,3,ComponentCCl4inCTC=99%(Mass),T：20P：6barFlow:10000kg/hrComponent(Mass-Frac)CCl4:0.4CHCl3:0.54CH2Cl2:0.06N2:0,Calculationtype:EquilibriumNstage:20Condenser:Partial-Vapor-LiquidT:80.3Distillaterate:6164kg/hrRefluxratio:5(Mass)Feedstage:10(on-stage)Pressure:Stage1:2barStage2:2.02barPdrop:0.235bar,Initialvalue,Thestart-upofadistillationcolumnthatseparatesamixtureofCH2CL2,CHCL3andCCL4.,FEED,COL1,DesignSpec:,Out_P:,VVENT:1.01VTOP:1.01VCTC:1.01VFEED:2.12444,Basemethod:,NRTL,Overview,2020/5/1,4,Thissimulationisofthestart-upofadistillationcolumnthatseparatesamixtureofCH2Cl2,CHCl3andCCl4.Thedynamicsimulationisapressuredrivensimulation,sotheAspenPlusmodelincludesvalvesonthefeedandproductlines.InAspenPlusDynamics,thecolumnisstartedupfromacold,emptyinitialcondition.Thepre-builtEmptyscriptisusedinAspenPlusDynamicstoresetthecolumntobeemptyandfullofNitrogenat20Cand1.01bar.Tousethisscript,NitrogenmustbeincludedinthecomponentlistintheAspenPlusmodel.Duringstart-uptheinertgashastobeventedfromthecolumnandsobothvaporandliquidtopproductstreamsmustbepresent.Therefore,intheAspenPlusmodel,bothliquidandvaportopproductshavebeenconnectedandaCondensertemperaturespecificationisusedwhichgivesasmallvaporproductflow.,GotoAspenPlusDynamicsmodel,2020/5/1,5,BeforeenteringanydynamicdatainAspenPlus,youwouldusuallyrunasteady-statesimulationtoensureitcompletesnormally.Beforeyoucanenterdynamicdata,youhavetoclicktheDynamicbuttonontheDynamictoolbar.Thisenablesyoutoaccessthedynamicinputdatasheetsforeachblock.TheRadFracblock(COL1)containsformsthatrequiredynamicdata,sothestatusindicatoronthestatusbarchangestoRequiredInputIncomplete.,Condenser:LMTDReboiler:Constanttemperature140RefluxDrum:VerticalEllipticalLength:2mDiameter:1mSump:EllipticalLength:2mDiameter:1.5mHydraulics:Simpletraystage1:2Stage2:19Diameter:1.5m,COL1,TheSimpleTrayoptionhasbeenusedintheHydraulicstaboftheColumnDynamicfolder.TheRigorousoptionisnotsuitableforsimulatingthezeroflowratesduringstartup.,ExportDynamics(PressureDriven),AspenPlusDynamics,2020/5/1,6,Initialization-Reconfigure,2020/5/1,7,1.SwitchtheoutputconnectionofthePressureControllerCOL1_CondPCfromtheVentValvetotheCondenserMediumflowrateasfollows:ClickthecontrolsignalbetweenCOL1_CondPCandvalveVVENT.Right-click.SelectReconnectDestination.ReconnectittotheinputconnectionatthetopoftheCondenser.Selectthefirstvariableinthelist,Mediumflowrate.ClickOK.,2020/5/1,8,2.ReconfigurethePressureControllerasfollows:Double-clickonittodisplaytheFacePlate.ClickontheyellowConfigurebutton.ClickontheInitializeValuesbutton.SettheGainto10.ControlleractionisDirect.SwitchtotheRangestab.SettheRangeminimumfortheOutputto1000kg/hr.ClosetheConfigureformandFaceplate.,Initialization-addFC,2020/5/1,9,3.Addaflowcontrolleronthecolumnfeedasfollows:DragaPIDIncrmodelontotheflowsheet.Right-clickthecontrollertorenameittoFC.DragaControlSignalstreamontotheflowsheet.ProcessVariable:ConnecttheControlSignalstreamtotheoutputarrowontheFEEDstreamlabel.ScrolldowntoselecttheTotalmassflowvariable.ClickOK.ConnecttheotherendofthecontrolsignaltotheinputofFC.SelecttheProcessvariableinput.ControllerOutput:RepeatthisprocesstoconnecttheControlleroutputfromcontrollerFCtothevalveVFEED.Configure:ClicktheInitializeValuesbuttonandthenchangethecontrolleractiontoReverse,thatis,ifthefeedflowistoohighthecontrollershoulddecreasethevalveposition.Changetheintegraltimeto0.5minutes.,Initialization-addTC,2020/5/1,10,4.AddaTCasfollows:DragaPIDIncrmodelontotheflowsheet.Right-clickthefiletorenameittoTC.ProcessVariable:Theprocessvariableisthetemperatureofstage16inthecolumnControllerOutput:TheoutputistheReboilerheatingmediumtemperature.Configure:ChangetheactiontoReverse.SetthePVrangeto80-125andtheOPrangeto20-260.,Initialization-Empty,2020/5/1,11,Closethevalve,VVENT,inthecolumnventstreamasfollows:SelectthevalveVVENT.Right-clickFormsManipulatetodisplaythevalveposition.Changethepercentageopentozero.,RuntheEmptyscriptandresetthecolumntobefullofNitrogenasfollows:SelecttheColumnblock.Right-clickScriptsEmpty.WaitfortheScripttofinishrunning.ClickOK.,Initialization,2020/5/1,12,OpentheFacePlatesforalltheControllers.ClicktheHandicontoswitchalltheFacePlatestoManualMode.IntheFacePlates:Settheoutput(OP)oftheflowcontroller,FC,tozero.Settheoutputofthetemperaturecontroller,TC,to20C.Settheoutputofthepressurecontroller,COL1_CondPC,to1000kg/h.,ChangetheAspenPlusDynamicsrunmodefromDynamictoInitializationasfollows:ClickRun.ClicktheTakeSnapshoticon.SavethesnapshotasColstart.,CreatetheTaskColstarup,2020/5/1,13,CreatetheTasktostartupthecolumn.GototheFlowsheetsectionoftheSimulationExplorer.Double-clicktheAddTaskicon.Namethetaskcolstartup.Deletethedefaultsettingsofthistask.Right-clickInsertFilebrowsetofindthecolumnstartup_task.txtfileincludedwiththisexample.Analyzethetasktounderstandwhatitwilldo.Right-clickCompile,orpressF8,tocompilethetask.Closethetexteditorwindow.,Task,2020/5/1,14,TaskcolstartupRunsat0/Ensurethatcontrollersareinmanual/Addsomefeedtothecolumn/Waitforthesumpleveltoreach2mandthenturnoffthecolumnfeed/Putthepressurecontrollerintoauto&changesetpointto2bar/Openthecolumnventvalvetopurgethenitrogen/Increasereboilersteamtemperaturegradually/Startthecolumnreflux/Continueincreasingsteamtemperature/CloseventvalvewhenN2ispurged/Puttherefluxdrumlevelcontrolintoauto&changesetpointto2/Addsomemorefeeduntilthesumplevelreaches2m/Increasereboilersteamtempto135/Waituntilthelevelintherefluxdrumrisesto0.5then./.putthesumplevelcontrollertoautomatic/andincreasetherefluxratetothefinalvalue/startthecolumnfeed-putthefeedvalveto50%open/Rampupthesteamtemperatureto140/Waituntilstage16temperaturereaches101.5andputthetemperaturecontrollertoAutomode/Changetherefluxlevel&sumplevelsetpointstothefinalvalue/Waitfor1morehourandpausethesimulation,2020/5/1,15,TaskcolstartupRunsat0/Putthepressurecontrollerintoauto,Colstarup,2020/5/1,16,Double-clickthecolstartuptaskintheSimulationExplorertoactivateit(otherwisei