傳質(zhì)與分離工程1第1頁，課件共23頁，創(chuàng)作于2023年2月Fig.21.332第2頁，課件共23頁，創(chuàng)作于2023年2月Triangleacdrepresentstheidealplateandtriangleabetheactualplate.Theactualplate,insteadofenrichingthevaporfromyn+1toy*n,accomplishedalesserenrichmentyn-yn+1.3第3頁，課件共23頁，創(chuàng)作于2023年2月ToapplyaknownMurphreeefficiencytoanentirecolumn,itisnecessaryonlytoreplacethetrueequilibriumcurveyeversusxebyaneffectiveequilibriumcurvey’eversusxe,whoseordinatesarecalculatedfromtheequation(21.70).4第4頁，課件共23頁，創(chuàng)作于2023年2月Howtoplottheeffectiveequilibriumcurve?Givingxn,findy*nfromequilibriumcurveandyn+1fromoperatingline,calculateynfromequation(21.70),thenplotpoint(xn,yn)…Howtodeterminethenumberofactualplates?Thereboilerisnotsubjecttoadiscountforplateefficiency,andthetrueequilibriumcurveisusedforthelaststepinthestrippingsection.5第5頁，課件共23頁，創(chuàng)作于2023年2月Howmanyactualplatesareneededintheleftconstruction?6第6頁，課件共23頁，創(chuàng)作于2023年2月Howmanyactualplatesareneededintheleftconstruction?Nofractionalactualplate,then7第7頁，課件共23頁，創(chuàng)作于2023年2月Murphreeefficiencycanbedifferentfromindividualplates,andthisismoreaccuratetocalculatethenumberofactualplatesthanbyoverallefficiencyofacolumn全塔效率.8第8頁，課件共23頁，創(chuàng)作于2023年2月3.BATCHDISTILLATION（間歇精餾

）

[pp.700-703]1)SimpleDistillation簡單蒸餾(自學)(1)Flowdiagram(RefertoFig.21.37)BatchFeed間歇進料CondenserCoolingwaterProductreceiverStill9第9頁，課件共23頁，創(chuàng)作于2023年2月Therearemanycaseswherebatchdistillation間歇精餾

ispreferred,particularlyinthefoodandpharmaceuticalindustries.Batchdistillationisusedwhensmallamountsofproductaremadeinapilotplanttoprovidesamplesforproductsamplingortesting.Features:1)Unsteadystate;2)Withoutreflux;3)One-stagepartialvaporizationprocess.Thevaporleavingthestillatanytimeisinequilibriumwiththeliquidinthestill.[yisinequilibriumwithx.]10第10頁，課件共23頁，創(chuàng)作于2023年2月BatchFeedCondenserCoolingwaterProductreceiver11第11頁，課件共23頁，創(chuàng)作于2023年2月(2)Rayleighequation（瑞利方程）HeaterEq.(21.83)isknownastheRayleighequation.dx/(y-x)canbeintegratedgraphicallyornumericallyusingequilibriumdata(y~xequilibriumrelationship).12第12頁，課件共23頁，創(chuàng)作于2023年2月(3)Foranidealmixture,Thatis,Becauseor13第13頁，課件共23頁，創(chuàng)作于2023年2月Afterintegrationbetweenlimits14第14頁，課件共23頁，創(chuàng)作于2023年2月Numberofmolesofproduct:DEXAMPLE21.9.Averageconcentrationofproduct:15第15頁，課件共23頁，創(chuàng)作于2023年2月Advantages.Theadvantagesofbatchdistillationarethatseveralproductscanbemadefromasingleunit,andcaneffectivelyhandlesludgesandsolids.Disadvantages.Foragivenproductrate,theequipmentislarger.Itrequiresmoreoperatorattention,usesmoreenergy,andbecauseitisadynamicprocess,ishardertocontrolandmodel.16第16頁，課件共23頁，創(chuàng)作于2023年2月2)BatchDistillationwithreflux間歇精餾/有回流的間歇蒸餾

[pp.702-703]Inmanycases,arectifyingcolumnwithrefluxisusedtoimprovetheperformanceofthebatchstill.Flowdiagram.Features:

Unsteadystate;Onlyrectifyingsectioninthecolumn.Productconcentrationdiffersfromdifferentoperations.17第17頁，課件共23頁，創(chuàng)作于2023年2月Twobasicoperationmethods:(a).Keepthetopcomposition(xD)constantbyincreasingtherefluxratioasthecompositionoftheliquidinthereboilerchanges.(b).Fixtherefluxratioandlettheoverheadproductpurityvarywithtime,stoppingthedistillationwhentheamountofproductortheaverageconcentrationinthetotalproductreachesacertain(某個)value.18第18頁，課件共23頁，創(chuàng)作于2023年2月Calculationandanalysisfortheoperationofadistillationcolumn.Theplatecolumnhasbeenestablished,andthefollowingdataaregiven:Equilibriumrelationship;xF;q;NandM

(Nactual).InordertoobtainoverheadandbottomproductswithrequiredmolefractionsofxDandxB,therefluxratioRDandthefeedplatepositionmustbedetermined.Calculationmethod:Trialanderror（反復試驗）.19第19頁，課件共23頁，創(chuàng)作于2023年2月AttentionsofOperationanalysisofdistillationcolumn:(a)Suitablefeedplateposition;(b)Keepmaterialbalance:IfDandBchanged,xDandxBwillbechangedtoo.(c)Refluxratioisthekeymeasureofcontrollingproductquality.[Forexample,ifNisgiven,RDxD,xB.](d)IfxFchanged,feedplatepositionshouldbechangedtoo.20第20頁，課件共23頁，創(chuàng)作于2023年2月4.AZEOTROPICANDEXTRACTIVEDISTILLATION[pp.131]（恒沸精餾和萃取精餾）Whenrelativevolatility（相對揮發(fā)度）

nearorequaltounity,theseparationofcomponentsisdifficultbyconventionaldistillation,orimpossiblebecauseofazeotrope恒沸混合物

formation.Basicprinciplesofazeotropicandextractivedistillation:Addingathirdcomponent(solvent)toincreasetherelativevolatilityoftheoriginalcomponents,sothatthemixtureswithrelativevolatilitynearorequaltounitycanbeseparatedbyconventionaldistillation.21第21頁，課件共23頁，創(chuàng)作于2023年2月(1)

Azeotropicdistillation恒沸精餾Materialscalledentrainers(夾帶劑)(thirdcomponent)areaddedtotheoriginalmixture,andusuallyanewazeotropewithlowest-boilingpoints有最低恒沸點的恒沸物

isformed.Thenewazeotropewillofcoursecontainoneormoreofthefeedcomponents,andleavingbehindcomponent(s)whichmayberecoveredinthepurestate.Example:Recovery