燃煤过程中矿物质气化与亚微米颗粒形成的研究

华中科技大学硕士学位论文燃煤过程中矿物质气化与亚微米颗粒形成的研究姓名：高翔鹏申请学位级别：硕士专业：热能工程指导教师：徐明厚;姚洪20061108IPM100.0944µm3.95µm0.935µm0.935µmPM10(2002CB211602)(50325621)IIPM10PM10PM10PM10PM2.5IIIAbstractMostoffuelconsumedinpowerstationinChina,nowandinthefuture,iscoal.Coalcombustionsuppliesalargeamountofthermalenergy,andalsoreleasesagreatdealofparticulatemattertotheatmosphere.Someresearchersindicatethatcoalcombustionisoneofmainsourceofinhalableparticlesintheatmosphere,whicharegreatlyharmfulforhumanhealthandecologicalenvironment.However,littleinformationabouttheformationmechanismofsubmicronparticulatematter(SPM)anditscontrollinginthecombustionprocesswerereported.Therefore,ithasgreatscientificandpracticalsignificancestoinvestigatetheformationmechanisms,evolvementprocessandemissioncharacteristicoftheSPMduringcoalcombustion.Firstofall,thisthesisprovidedanoverviewofthepresentresearchesontheformation,emissionandnumericalsimulationoftheSPM,andanalyzedthedeficiencyoftheexistingresearch.Insecondsection,thethermo-gravimetricexperimentswerecarriedouttoinvestigatethevaporizedamountofashgottenbyLowTemperatureAsh(LTA).Then,themasssizedistribution,physicochemicalcharacteristicsandformationmechanismoftheSPMfrompulverizedcoalcombustioninadroptubefurnacewerediscussed.FactorsthatinfluencingtheemissioncharacteristicsandelementalpartitionoftheSPMwerealsoinvestigated,whichincludedthedistributionoffurnacetemperature,coalparticlesize,oxygenconcentrationandcoalcharacteristics.AsimilarbimodaldistributionofPM10withasmallandalargemodeat0.0944µmand3.95µm,respectively,wasobtainedinallruns.Basedonthecomparisonofconcentrationsofash-formingelementsinthesize-segregatedashwiththeirfilterconcentrations,itisconcludedthattheashsmallerthan0.935µmisformedbythenucleationofvaporizedashcomponentsandgrowthviacoagulationandheterogeneouscondensation.Coalparticlesize,oxygenconcentration,coalcharacteristicsandespeciallyfurnacetemperatureaffecttheSPMemissionsignificantlyinthecombustionprocess.Increasingfurnacetemperatureandoxygenconcentration,anddecreasingcoalparticlesizewouldleadtomoretheSPMformation.IVTobetterunderstandtheemissioncharacteristicsandchemicalcompositionoftheSPM,flyashwassampledintheentranceandexitofthedustcleaningequipments,suchasESPandventuriscrubber,inseverallarge-scaleutilityboilers.AsimilarbimodaldistributionofPM10wasobtainedinthestudiedboilers.Thesmallandlargemodesarelocatedat0.1µmand4.0µm,respectively.ThechemicalcomponentsaretheoxidesandsulfatesofalkalimetalintheSPM,whiletherefractoryoxidescontributtothemajorcompositionofcoarseparticle.Thecollectionefficiencyofthedustcleaningequipmentshadaminimuminparticlesizerangeof0.01-1µm.Theminimumwas65%and50%forESPandventuriscrubber,respectively.Thestudyprovidethebasesforresearchingandcontrollingtheemissionofparticulatematterfromthethermalpowerplant.Keywords:CoalcombustionPM10PM2.5SubmicronparticulatematterMineralmattervaporization√11“”“CleanCoalTechnology”“”“”CCT[1,2]19958“”2010“973”“”“”“973”SO2NOX“973”2.5µm1.170%30%2202033.7%[1]94%5.4%0.6%“”[2]195994.7%197669.9%907576%70%60%80%[3]1.1201562.6%205050%1.1[4,5]199019952000201576.276.171.362.916.617.124.026.92.102.002.747.065.104.802.012.63//0.210.7984%[6]200052.9%1.2200454[7]205060%200020105“”5[8]11.12050200.05~1µm[9-12]31.2[13]108kw108kw108T%19941.991.483.9232.419952.171.63/33.1320003.002.25.2852.920105.53.458.2154.72050159.52060200333%[14]19966MW28%3.97Mt1.2%1.5%[15]6819983220.289mg/m368%308WHO0.09mg/m395%200033811220042016FeBeAlMnPbCd[16-20]4[21-23][24-29]1.21.2.1PM2.5[30,31][32]SO2NO2O3COPM2.548PM2.50.046-0.160mg/m30.015mg/m33-10[33]19902040240/675/46.4/216/19.3%32%33%515.3/199071.3/20401.2.2(TSP)33NOXNH31.2.2.16819983220.289mg/m368%308WHO0.09mg/m395%2000338112200134111433.4%1011433.4%11333.2%[34]1.2.2.22070699%PM10100300km30km5km0.11µm[35,36]PM101.12.5%0.21.0%Cheng[37]199927.8%231999PM2.50.96[38]1.2.2.3[39]1.2.2.47[40][41-49],PM10,PM101.31.3.1[26,50,51]Quann[52,53]1600KSiO2Al2O3CaOMgOFeOSiO,Al2OCa,Mg,FeCCOHS0.01µm1.2Linak[54]Taylor[55]KNa8Quann[56]Nenniger[57]FeMgKNaSiAlCaSiAl4101.2[58]SiAlFeMgCa80QuannSarofim[53]NevilleSarofim[59]0.010.03µmMgFeSi[60,61]91.3.2ESP100%PM106995%0.11µm[62]Ohlstroem[63]1000MW12Mt2400t/dESP99.9%900t/yMeij[64,65]0.03%Lind[66]ESPESPESP99.299.8%0.12µm9697%Maguhn[67][68,69][70]PM10PM2.592.47%35.56%PM2.590.6%[71]810AndersenESP1.4973“”2002CB21160212341122.1123[72,73][74]:(1)(2)300400(3)400900(4)900COH212312123456771267345Walker[75]2.1EaEEa1/2E13“”2.12.22.2.1[76]:1NaKCaMg12%23142.22.22.2.2SiAlFeCaMgNaKSTiP2.1[77]TiPSiAlFeCaMg90%XRDEMPASEM[78]2.1(%)(%)SiO210-70MgO0.5-8Al2O38-38Na2O0.1-8Fe2O32-50K2O0.1-3CaO0.5-30SO30.1-3015160-80%23452.3[79-81]CaO16Na2O(g)+K2O(g)2.480[82-84](1)(2)(3)(4)2.32.42.4.12.4.1.1PrimaryFragmentation[85,86]0.1µm172.32.4182.4.1.2Swelling[87-88]2.4.1.3SecondaryFragmentation2.5“”19[89,90]0.5µmHelble[91]2.5“”202.4.2“”80µm1450oC2000oC[92]2.62.62.6[93]212.4.3Yan[94]Yamashita[95]2.4.42.4.4.1[52,54,55]1800KSiO2Al2O3CaOMgOFeOSiO,Al2OCa,Mg,FeSiO2CO?SiO(g)CO2CaOCO?Ca(g)CO2MgOCO?Mg(g)CO222Al2O32CO?Al2O(g)2CO2FeOCO?Fe(g)CO2CHSSiO2C?SiO(g)CO21%1