大学课件-化工原理下册-萃取小结english

LIQUID-LIQUIDEXTRACTION（briefsummary）1unitoperation-toseparatecomponentsinaliquidmixture2differenceinsolubility3solventisaddedtochangesolubility4StepsInvolvedInExtractionsolute:Aoriginalsolvent:Bsolvent:SB,SimmiscibleS,A(Extract)B,A(Raffinate)B,SpartiallymiscibleS,A(B)(Extract)B,A(S)(Raffinate)RemovalandrecoveryofsolventfromeachphaseExtract→ExtractliquidE′y′（A+（S、B））Raffinate→RaffinateliquidR′x′(B+（A、S））afterextractionprocessBABAxxyyAAxysupercritical-liquidassolvent(lastdecade)Liquid-likedensityGas-likediffusivityexhibitenhancedsolvatingGas-likeviscositypowerNon-toxicEnvironmentallyacceptableCO2isveryattractivealternativeABREMMisadditionpointSEisdifferencepointthelevellawright-angledisoscelestriangulardiagramABSR0E0MR1E1R2E2EnRnKsolubilitycurve3)conjugatephases1）solubilitycurve2）tieline4)plaitpoint二苯基乙烷糠醛二十二烷图8-14温度对溶解度曲线的影响45°C80°C115°C140°C00.200.400.600.801.000.200.400.600.801.00图8-15温度较高时的II类物系相图SBAuxiliarycurveASBR0R1R2RCR4E1E2E3E4KR3ECxACC2C3C辅助曲线图8-16辅助曲线ASBR1R2R3R4E1E2E3E4KC4C3C2C1辅助曲线distributioncurveanddistributioncoefficientabscissa：SoluteconcentrationxAinRaffinatecoordinate：SoluteconcentrationyAinExtract图8-18三角形相图与分配曲线AME0SBR0K0yAy=xxA分配曲线distributioncoefficientdistributioncoefficientfororiginalsolventBBBxykAAAxykAAAxkyCalculationofL-LExtractionNumberofstages:NEfficiency:NNPABSFMERSingle-stageExtractionwithPartiallyMiscibleSolventABR'REFMSextractliquidandraffinateliquidABSFMERE'R'BFSE1R1R2E2Aamountofsolventy'AmaxABSy'AmaxERFMyA'图8-24溶剂用量对单级萃取的影响AMSBRR2EE2FFBR1RE1M'ASE1E2'E'y2'ymax'yA'EMultipleContactco-currentflowsheetcounter-currentflowsheet12iNR1R2RiE1E2EiENFxfS0S1S2SiSn图8-26多级错流萃取流程IRNSnRn'IIE'SERi-1Rn-1co-currentflowsheetABSFM1R1E1M2R2E2M3R3E3R'31Fxf图8-29多级逆流萃取流程IIRNSRR'IE'SEii+1N-1NSE1RiR1Ri-1E2EiEi+1counter-currentflowsheet1）massbalanceE1、RNnotconjugatephasesDummyflowD：right→leftmDmRmSmFmEqqqqqN1mMmRmEmSmFqqqqqN1AFMRNR'NE1DBS2）massbalanceovereverystagemDmRmSmRmEmRmEmRmEmFmEqqqqqqqqqqqNNNii111213）graphicmethodEquilibriumrelation：Ei,RiOperatingrelation：Ei+1,RiAFMRNR'NE1DR1E2FSRNE1DFSMRNE1→R1E2……ABFDSMR4RN'RNR3R2R1E1E2E3E4→→xn≤xNN=nE1、D→R1(inEquilibrium)D→→→E2(Operatingrelation)F,S,Rn→图8-31在直角坐标中图解下场论基数NABFRn'RnE1yi+1xiM12iDS(a)xfxiyi+1y1xn操作线y分配曲线x123456iCi(b)0distributioncurve图8-35溶剂比对极点的影响ABFSRNE1DD'MM'M''S/F，D,D=F-E1D-leftoftriangulardiagram，DummyflowDfromlefttoright(S/F)affectseparatingoperation(S/F)additionpointManddifferencepointDNxAyA0图8-36溶剂比对操作的影响操作线xfxN分配曲线321S/F（S/F）minD=DminNS/Fy1slopeofoperatinglineDminRNF、DminE1FE1RNE1,FSMMSMFMqqmFmSmin)(B,ScompletelyimmisciblemixtureS、BareconstoverextractionprocessRatioofsolutetosolvent:X---kg(A)/kg(B)Y---kg(A)/kg(S)single-stageextractionmmmm)(0FSBSBXmmYXmmYYX0DistributioncurveXFY0Cslope（-mB/mS）Operationope.DXYco-currentflowsheetmmmmmmmmmmmmmmNiXmmYXmmYiSBiSBi,,2,1)(10XY0XFY0-mB/mSX1X2X4X3Y1Y2Y3Y4counter-currentflowsheetmmmSmYi+1)(01NSBiSBiXmmYXmmY(mS/mB)affectseparatingoperation(S/B)(S/B)minN01min)(YYXXmmNFBSBABAxxyysuitablesolventforextraction•SelectivityBABAxxyyBBAAxyxySelectivitycoefficientB,Scompletelyimmiscible,βgoodforseparation•Recoveryofsolvent•PhysicalpropertieskA，β，goodforseparationgoodseparationability=1,extractioncannotutilizedtoseparatemixtureSTAGE-WISEEQUIPMENTFOREXTRACTIONDIFFERENTIALCONTACTEQUIPMENTFOREXTRACTION1.differentialcontactors-continuousvariationonCstage-wisecontactors-C2.externalwork3.tower/combinedunitsTheMixer-settlerSprayColumnScheibelColumnPackingcolumnBaffle-platecolumns转盘萃取塔搅拌填料塔Centrifugalextractors