2025/6/2116.4Fluidizedbedcombustionboiler
第四节流化床燃煤锅炉流态化现象与过程流化床的基本特性流化床的分类鼓泡流化床工作原理、特点和组成循环流化床工作原理结构组成优缺点技术流派关键技术
2025/6/2126.4Fluidizedbedcombustionboiler
第四节流化床燃煤锅炉Inthe1970s,fluidized-bedcombustiontechnologywasfirstappliedtolarge-scaleutilityboilerunitstoexplorenewwaysofburningsolidfuels,especiallyhigh-sulfurcoal,inanenvironmentallyacceptableandefficientmanner. 70年代流化床技术应用于电站锅炉Inconcept,fluidizedbedsburnfuelinanair-suspendedmass(orbed)ofparticles.Bycontrollingbedtemperatureandusingreagentssuchaslimestoneasbedmaterial,emissionsofnitrogenoxides(NOx)andsulfurdioxide(SO2)canbecontrolled.采用低温煅烧和石灰石脱硫Additionalbenefitsoffluidized-bedcombustionincludewidefuelflexibilityandtheabilitytocombustfuelssuchasbiomassorwastefuels,whicharedifficulttoburninconventionalsystemsbecauseoftheirlowheatingvalue,lowvolatilematter,highmoisturecontentorotherchallengingcharacteristics.较宽的燃料范围
2025/6/213Thefluidizingprocessinducesanupwardflowofagasthroughastackedheightofsolidparticles.Athighenoughgasvelocities,thegas/solidsmassexhibitsliquid-likeproperties,thusthetermfluidizedbed.Thefollowingexamplehelpsillustratetheprocess.ProcessofFluidized-bed
2025/6/214Fig.(a)showsacontainerwithanairsupplyplenumatthebottom,anairdistributorthatpromotesevenairflowthroughthebed,andachamberfilledwithsandorothergranularmaterial.AsshowninFig.(b),Ifasmallquantityofairflowsthroughtheairdistributorintothesand,itwillpassthroughthevoidsofanimmobilemassofsand.Forlowvelocities,theairdoesnotexertmuchforceonthesandparticlesandtheyremaininplace.Thisconditioniscalledafixedbed.ProcessofFluidized-bed
2025/6/215Byincreasingtheairflowrate,theairexertsgreaterforcesonthesandandreducesthecontactforcesbetweentheparticlescausedbygravity.AsshowninF