feed profiles for solvent switching：溶剂交换饲料公司

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1、ApplicationsofAPIProcessSimulation,Example3FeedprofilesforsolventswitchingObjectiveTheobjectiveofthisexampleistocomparedifferentfeedprofilesforswitchingsolventsinabatchvessel.Thefirstmethodinvolvesafeedingnewsolventcontinuouslyintothevessel,whilethesecondmet

2、hodinvolvesa“putandtake”strategyinwhichthenewsolventisfedasaseriesofshots.Asimulationmodelwillbeusedtocomparetheamountofsolventandprocessingtimethatisrequiredbythetwoapproaches.ProcessDescriptionObjectives:(i)Determinetimerequiredtoachievethedesiredconcentra

3、tion(99%)ofnewsolvent.(ii)Determinetheamountofreplacementsolventthatmustbesuppliedfromthefeedtank.ManipulatedVariable:Feedrateofreplacementsolvent.Twodifferentfeedstrategieswillbecomparedinthisexample:(i)fedbatch;(ii)“putandtake”.Thesearedescribedingreaterde

4、tailinthenextsection.Variablesandparameters:,transferrateofsolvent;,masstransfercoefficient;,transferareaperunitvolume;,concentrationofsolventinbulkphase;,partitioncoefficient;,vaporpressureofsolvent;,Antoineequationconstantsforsolvent;,temperatureofvaporpha

5、se.BalanceandPropertyEquations:(Antoineequation)(UNIFACmethod)ApplicationsofAPIProcessSimulation,Example3SolventFeedProfilesThebatchvesselisequippedwithacontrollerwhichcanimplementtwodifferentmethodsformaintainingthevolumeofsolventwithinaspecifiedrange.Fed-b

6、atch.Thecontrollerattemptstomaintainthevolumeofliquidinthebatchvesselatthemid-pointbetweenthespecifiedminimumandmaximumlevels.Intheinitialstagesthevolumeofmaterialisabovethemid-pointvalue.Thefeedisswitchedonaftersufficientamountsoftheinitialsolventhaveevapor

7、atedsothatthevolumefallsjustbelowthemid-point.Atthispointthecontrolleropenstheflowvalveandadjuststheflow-ratecontinuouslytomaintainthevolumeatthemid-point.Figure1.Levelprofilefor“fed-batch”controlschemePutandtake.Theflowcontrollerwillattempttomaintainthevolu

8、meofliquidinthebatchvesselintherangebetweenthespecifiedminimumandmaximumlevels.Whenthelevelreachestheminimumvalue,theflowvalveisopenedtoitsmaximumvaluetoallowforrapidfillingofthenewsolventuntilt