清华大学化工原理第二章吸收小结ABSsummary.ppt

Summary Absorption Knowledge Threemainparts Part1 howtoachieveanabsorptionprocess Part2 howtodeterminethebasicparametersofapackedcolumn Part3 howtoenhanceanabsorptionprocess Part1 howtoconductanabsorptionprocess 1 absorption Richgas solutegasandinertgas Diluteorleangas Weakorfreshliquid Strongliquid Regenerationprocessie Strippingordesorption solute Platecolumnpackedcolumn Part1 howtoconductanabsorptionprocess 2 Distributorandredistributorpackingspackingsupportpackingcover Part1 howtoconductanabsorptionprocess 3 packingsdumpedpackingsstackedpackingsconstructedpackingsporosity 60 90 Part2 howtodeterminethebasicparametersofapackedcolumn DiameterandHeight DiameterofpackedtowerSuperficialgasvelocityfloodingvelocity Howtodeterminefloodingvelocity L 0 L1 L2 A A B B Pressuredropofgas Velocityofgas slope 1 8 Countercurrentflowandcocurrentflow Continousphaseanddispersedphase Loadingpointandfloodingpoint Heightofpackedtower 1 limitinggas liquidratiooperatinglineandequilibriumline X Y X2 Y2 Y1 X1 WiththedecreaseofL L 1 1 2Lmin V Y2L X2 V Y1L X1 Y X dH H Heightofpackedtower 2 Numberoftransferunits NTU Heightofatransferunit HTU V Y2L X2 V Y1L X1 Y X dH H KYa overallvolumetricmasstransfercoefficientbasedongascomponent Part3 howtoenhanceanabsorptionprocess MechanismofmasstransferbetweenphasesHowtoreduceresistenceHowtoenlargedrivingforceHowtoimproveapparatus Mechanismofmasstransferbetweenphases Twofilmtheory pA interface pAi cAi cA diffusionineachboundarylayerconvectionoutsidethelayerequilibriumattheinterface Howtoreduceresistance pAi cAi H Diffusivity diffusioncoefficient individualmasstransfercoefficientoverallmasstransfercoefficientHenry sLawresistance Howtoenlargedrivingforce solventtemperatureabsorptionwithchemicalreaction egfastandirreversible X Y OL EL1 EL2 EL3 Howtoimproveapparatus newpackingsporosityandareaflowconditionmembraneabsorptionarea areapervolumeofapparatus flooding f