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1、AbsorptionPrinciples of Chemical Engineering-CDUTHenrys lawIf the composition of solute in gas liquid and liquid phase is expressed by partial pressure P and mole fraction xrespectively,then:E Henry coefficient，kPaselectivityHenry coeffcient1.px relationshipsoluble gasnoteindissolvable gasE smallE l
2、argePhase equilibrium relationship of absorption processExp Principles of Chemical Engineering-CDUTIf the composition of solute in gas liquid and liquid phase isexpressed by partial pressure P and mole concentration xrespectively,Henrys law isH solubility coefficient，kmol/(m3kPa)solubilitysolubility
3、 coefficient2.pc relationshipsoluble gasnoteindissolvable gasH largeH smallHcp*Phase equilibrium relationship of absorption processPrinciples of Chemical Engineering-CDUTIf the composition of solute in gas liquid and liquid phaseis expressed by mole fraction y and x respectively,Henryslaw ism consta
4、nt of phase equilibriumsolubilityconstant of phase equilibrium3.yx relationshipsoluble gasnoteindissolvable gasm smallm largemxy*Phase equilibrium relationship of absorption processPrinciples of Chemical Engineering-CDUT4.YX relationshipIn the calculation of gas absorption with low concentration,the
5、composition usually expressed by mole fraction y(or x)withconstant datum.Y=mole function of solute in gas phase/mole function of inert component in gas phase=y/(1-y)X=molar function of solute in liquid phase/molar function of solvent in liquid phase=x/(1-x)Phase equilibrium relationship of absorptio
6、n processPrinciples of Chemical Engineering-CDUTxXX1yYY1XXmYY1*1*fromtoexpressed aslow composition absorption1m X 1simplified asmXY*XmmXY11*Phase equilibrium relationship of absorption processPrinciples of Chemical Engineering-CDUTThe expression of Henrys law can be rewritten as following:Epx*Hpc*my
7、x*mYX*phase equilibrium relationship of absorption processThe expression of Henrys law Principles of Chemical Engineering-CDUTThe relationship among coefficients of Henrys law expression is derived as follows:EH relationshipEm relationshipHm relationshipdensity of solutionmole mass of solvent SHEMS总
8、pEm mMpHS1总phase equilibrium relationship of absorption processthe expression of Henrys lawPrinciples of Chemical Engineering-CDUT2021/4/12influencing factors of phase equilibriumthe phase equilibrium coefficient is directly proportional to Henryscoefficient and inversely proportional to the total p
9、ressure of the system.Henrys coefficient increases with the increase of temperature.The phaseequilibrium relationship at different temperatures can be calculated byreferring to the corresponding manual or using the formula.Therefore,the phase equilibrium coefficient will increase with the increase oftemperature and decrease with the increase of system pressure.phase equilibrium relationship of absorption processthe expression of Henrys law