基于超细颗粒磁流化床干法包裹及声场流态化研究

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1、中国石油大学（华东）硕士学位论文超细颗粒磁流化床干法包裹及声场流态化研究姓名：李彦申请学位级别：硕士专业：化学工程指导教师：郭庆杰20060501UltrafineParticleDryCoatinginaMagneticFluidizedBedandFluidizationinanAcousticAssistantFluidizedBedLIYan(ChemicalEngineering)DirectedbyProfessorGUOQing-jieAbstraetInrecentyears,moreandmoreattentionhasbeenf

2、ocllsedonultrafineparticlebecauseofitsuniquecharacteristics．Plugsandchannelsoccurwhenultrafineparticlewerefluidizedinabubblingflmdizexibedduetostrongcohesiveforcebetweenparticles．Inthispaper,drycoatinginamagneticfluidizedbedandfluidizationinanacousticfluidizedbedwereemployedto

3、improveparticleflmdizatmnquality,respectively．DrycoatinginamagneticfluidizedbedwasIntroducedtoachievethesurfacemodificationofultrafineparticles．Magneticringwasencircledaroundtheglassflmdizcdbedtogenerateuniformaxialmagneticfield,withmagneticparticles(Fe304)beingused够host(corns

4、tarch)andSi02asguestparticles．Twomechanismsencounterincoatingprocess．OnewastheshearingforcewhichgeneratedfromFe304movingandcollidingwithhostandguestparticlesundermagneticfield，theotherwasgasdragforceinthefluidizedbed．Theoperatedparameters．suchashost／gnestadditionalratio，granul

5、arity，coatingtime，magneticparticlesadditionalratioandmagneticfeldintensitywereexaminedinthisexperiment-IthasbeendemonstratedthatthecoatedcornstarchfluidizationqualitywassimilartoGeldartAgroupparticles，whencoatingtimeexceeds10minutes，guestparticles’averagediameterwas2．5／amor500

6、am，Vhosffguemweightratiorangesfrom3％to10％andmagneticfieldintensitywas12．27mT．Thecollapseexperimentshowsthatthecoatedcornstarchhaslowergasretardarcecapabilitythancornstarch．Thefluidizationbehaviorofvariousnanometerandmicronparticles，includingSi02，Ti02andcornstarchparticleswithp

7、rimaryparticlediameterfrom5nmto10．7mn，wasinvestigatedinanacousticassistantfluidizedbed．Ithasbeenfoundthattherelativelyuniformsmallparticleagglomerateshavebeenformedandfiuidizedhomogenouslyunderlowacousticfrequenciesandhigllacousticpressure．Effectsofacousticfrequencies，acoustic

8、pressure，andwaveshapeonfiuidizationcharacteristicswereinvesti