应用激光感生击穿光谱对煤中Fe、Ca、Al的定量研究

华中科技大学硕士学位论文应用激光感生击穿光谱对煤中Fe、Ca、Al的定量研究姓名：陈文申请学位级别：硕士专业：热能工程指导教师：陆继东20060417I*FeLIBSTeN66AlCaFeLIBSLIBSLIBS*(20020487013)50576029IIABSTRACTCoalqualityanalysisisconcernedbypowerplantsallthetime.Themineralelementscontentincoal(eg.alkalimetal,Fe,etc.)isanimportantparameteraffectingdepositionslaggingandcontaminationofheatingsurfaces.Theelementcompositionofcoalcouldbeusedtocalculatecombustionheat,principalcombustiontemperature,theconstituentsofcombustionproductandthermalequilibriumanditisoneofthemostnecessarydataforthermalcalculationandcombustionadjustmentofboiler.Theavailablemineralelementscontentsusingtraditionalmethodsshouldtransfercoaltoash,whichistroublesomeandtime-consuming.Abriefintroductionandcommentoftypicalfastelementanalysistechnologiesweregiven,andanewmethodlaser-InducedBreakdownSpectroscopy(LIBS)wasproposedforfastanalysisofcoal.Firstly,theprincipleandcharacteristicsofLIBSwasintroduced,meanwhile,thegenerationandinfluenceofcontinuumbackgroundoccurredinlaserplasmawasanalyzed,andthenthequantitativecalibrationmodelwaspresented.TheLIBSexperimentalset-upwasdescribedindetails.Theoretically,twophysicsparameters,i.e.plasmatemperatureTandelectrondensityeN,whichaffectedspectraintensitysignificantlyintheory,wereexpatiatedandvalidatedbyexperimentsofchoosingcoalsamples.ThevaluesofplasmatemperatureTandelectrondensityeNwereobtainedthroughthegainedcoalspectra.Sixrepresentativecoalsampleswereselectedforquantitativeanalysis,whichwasanalyzedbytraditionalmethodpriortoexperiments.Spectrawereobtainedandqualitativelyanalyzedfirst,theresultsthencomparedwiththepublishedliteratures,whichgivereasonablequalitativeresults.Inordertogetfurtherquantitativeanalysis,thecalibrationcurvesofAlCaFewereconstructedbyspectraandchemicalanalysisresultsAtthesametime,amethodofhowtodeterminetheupperlimitoflinearcalibrationrangewasproposed.Atestcoalsampleofunknowncompositionwasanalyzedutilizingcalibrationcurves,subsequently;theresultswerecomparedwithtraditionalmethod,whichIIIshowedcloselyconsistentbetweenLIBSandtraditionalmethod,therefore,itvalidatedthatLIBSiscapableofcoalanalysis.Finally,asummarizationwasgivenandthesuggestionandprospectwereproposedforthefastanalysisofcoal.Keywords:plasmaLaser-InducedBreakdownSpectroscopy(LIBS)elementalanalysisplasmatemperaturecalibration1111200419.718.730%202033.7%75%,,,[1]CHONSCaNaMgFeAlNaKMgCaFeTiAlNaCaKFe[2](Laser-Induced2BreakdownSpectroscopy)LIBS1.1123‹XXRFXXKLXXX3XRFXXX11‹PNGAAPNGAA1-11-1PNGAABertholdRGIVEAGMCIGamma-MetricsPNGAA304Gamma-Metrics0.25%0.4%1992Gamma-Metrics1993199416%14%20%199019954002000D-TCHONSAlSiFeCaTiMgNa12PNGAA()‹LIBS20LaserInducedBreakdownSpectroscopyLIBS5(MicrowaveInducedPlasmaSpectroscopyMIPSICP-AESX(XRF))‹MCM-III0.5%CSIRO0.08%~0.28%3min1.21964Maker[3]6401964707019801983LIBS(Laser-InducedBreakdownSpectroscopy)[4-8]20LIBSLIBSLIBS1.2.1LIBS[9]Cu107W/cm2Al3×107W/cm2108W/cm2[10-14]7[15-17]Al[18-20][21-26]1.2.2LIBSAkshayaKumar[27]MgMnCrLosAlamos1996TRACER124[28]DavidA.CremersLeonJ.Radziemski[4]LIBSClFCapitelliColao[29]CrCuFeMnNiPbZn8RSD%ICPAESICP-AESLIBSLIBSLIBSAkiraKuwako[30]LIBSNaNa0.1ppbArca[31]LIBSSiCaClNaKCrMississippiDIALDiagnosticInstrumentationandAnalyticalLaboratoryLivermoreSandiaCooperativeresearchcenterforcleanpower[32-33]1-11-1LIBS(nm)(µg/g)Na589.03Ca422.76Mg285.09Fe275.010Al309.0991997DepartmentofEnergyDOEEnvironmentProtectionAgencyEPA8AsBeCrCdPbHg[34]ICP-AESXMississippiDIALDiagnosticInstrumentationandAnalysisLaboratoryLivermoreSandiaLIBS1997[35-37]H.Zhang[38]D.K.Ottesen[39]LIBSCaFeAlLindaG.Blevins[40]LIBS8NaKCaMgFeSiAlTiJ.Gruber[41]12CrCuMnNiQ.Sun[42]MnSi403.45251.6nmB.LeDrogoff[43]LIBSAlMgFeSiMnCu10Sun[44]LIBSZn60mJLIBS100mJNASALIBSMarsSalle[45-46]LIBSYoonyeolYoonTaesamKim[47]LIBSFeCaMgAlSiXFeM.Castillejo[48]L.Burgio[49]O.Samek[50]111.3FeAlNaFeAlCaLIBS1.4LIBSLIBS12LIBS6LIBSLIBSLIBSLIBS132202.12-1142-1IntensifiedChargeCoupledDeviceICCD/2.1.11062W/cm[51]15en()2eredaienknkkkdtdn+−−=2-1einkeankednk2ernkLτ2-12ernkebn2-1()Ldaieebkkknnτ−−≤0ln2-20enebn0.001ebnthIthI()feLeaLiathVnkcnIln12τω=2-3VfanciωLeakeakan2-3200104×133.322PathI15-50nsQ16NdYAG760×133.322Pa102MW/cm2-22-2(1)free-freeemission(-)(2)free-boundemission(-)(3)bound-boundemission(-)172-3Mg383.8nm383.0nm2-3Mg383.8nmMg383.0nm11µs1821µs383.8nm(383.0nm)31µs30µs2.2thI(1011-1Ks)11000060000KICP6000~10000K50007000K210151019/3cmICP10111015/3cm1015/3cm19Brech1964LIBSLIBS[52]1µm20LIBSLIBS2.3520ns2-221100ns1µs30µs1µs2-42-42-41µs1µs10µsTd22Signal-to-NoisyRatio,SNR[53]2.42.4.1CalibrationFreeModelA.Ciucci[54]123LocalThermalEquilibrium,LTE2-4()exp()kikkikBssgAEkTIFCUTλ−=2-4λkikiIλLIBSsCFλkiAkikEkgBk()TUsTkEkgkiANISTNationalInstituteforStandardsandTechnologyFTsC23kxE=2-5lnkikkiIygAλ=2-61BmkT=−2-7()lnsssFCqUT=2-82-42-9symxq=+2-9()lnlnkikskkiBsIECFgAKTUTλ=−+2-102-10kElnkikkiIgAλkElnkikkiIgAλmsq2-4FF1()1sqssssCUTeF==∑∑2-11()exp()kskBEUTgkT=−∑2-12100%12422-52-5(NIST)kiAkgkELIBSkiIλkikkiAgIλlnkEkikkiAgIλlnTCFFmsq252.4.2[55-63]ki()()()381kvlkkkikiiiNghcIvFedvNgπλ−=−∫2-13FhckiλiNkNigkgik()vkll()kνv()()∫∞+∞−−+−=2202axtdteakvk