气体分布器对内循环三相生物流化床反应器动力学性能的影响

Thegashold up,liquidcirculationvelocityandvolumetricoxygenmasstransfercoefficientwereinvestigatedbyexperimentsinaninternalcirculationthree-phasebiologicalfluidizedbedreactorwiththreedifferentgasdistributors.Theresultsshowedthat,besidesthegasflowrateQ_g,thegasholediameterandtheholenumberperunitareaofdistributorarealsoimportantfactorsthataffectgasholdupε_ginsidethereactor.UnderagivenQ_g, thedistributorwithsmallerholehelpstoachievehigherε_g(asdidthemicroporedistributorinthiswork),buttheover-denselydistributedholesondistributorwillcausethesmallbubblestomergeintolargebubbles,leadingtodecreasedε_g(asdidtheceramicdistributorinthiswork).Forthecasesoflowergasflow-rate (Q_gU_cmainlydependsonthegasholdupdifferenceΔε_gbetweenriseranddowncomer,whileforthecasesofhighergasflow-rate,both Δε_gandflowresistancearedominatingfactors.WhenQ_gkeepsconstant,thedistributorwhichachievesalargerΔε_gleadstoahighercirculationvelocity.ThevolumetricoxygenmasstransfercoefficientK_LaincreaseswithincreasingQ_g,towhichtheincreasedspecificsurfaceareacontributesmostly.UnderagivenQ_g,thedistributorwhichachievesahighergasholdupresultsinahighermasstransfercoefficientK_La.