高爐回旋區(qū)內(nèi)氧煤燃燒行為數(shù)值模擬研究

高爐回旋區(qū)內(nèi)氧煤燃燒行為數(shù)值模擬研究高爐回旋區(qū)內(nèi)氧煤燃燒行為數(shù)值模擬研究

摘要：本文采用數(shù)值模擬方法，研究了高爐回旋區(qū)內(nèi)氧煤燃燒行為。通過數(shù)值模擬，探究了回旋區(qū)內(nèi)氧、煤氣流動特性及其相互作用關(guān)系。首先采用Euler-Euler雙流體模型對氧、煤氣流動場進(jìn)行了模擬，然后采用非平衡化化學(xué)反應(yīng)模型描述了氧、煤燃燒反應(yīng)，最后對氧、煤燃燒后生成的氣體進(jìn)行了流固耦合數(shù)值模擬。研究發(fā)現(xiàn)，回旋區(qū)內(nèi)的流動狀態(tài)與氧煤的燃燒反應(yīng)密切相關(guān)。氣流對燃料的輸送、擴(kuò)散和混合起到了關(guān)鍵作用。氧可以加速燃料的燃燒，而煤氣可以降低氧濃度，影響燃料的燃燒速率。結(jié)果表明，在高爐回旋區(qū)內(nèi)，煤的燃燒速率受到爐內(nèi)氧分布情況的影響較大。同時，研究還為優(yōu)化高爐操作提供了參考。

關(guān)鍵詞：高爐；回旋區(qū)；數(shù)值模擬；氧煤燃燒；流固耦合

Abstract:Thispaperusesnumericalsimulationmethodstostudythecombustionbehaviorofoxygen-coalintheblastfurnaceswirlingzone.Throughnumericalsimulation,theflowcharacteristicsandinteractionrelationshipbetweenoxygenandcoalgasintheswirlingzoneareexplored.Firstly,theEuler-Eulerdoublefluidmodelisusedtosimulatetheflowfieldofoxygenandcoalgas,thenthenon-equilibriumchemicalreactionmodelisusedtodescribethecombustionreactionofoxygenandcoal,andfinallythegasgeneratedbythecombustionofoxygenandcoalisnumericallysimulatedbyflow-solidcouplingmodel.Thestudyfoundthattheflowstateintheswirlingzoneiscloselyrelatedtothecombustionofoxygen-coal.Airflowplaysakeyroleinthetransportation,diffusionandmixingoffuel.Oxygencanacceleratethecombustionoffuel,whilecoalgascanreducetheoxygenconcentrationandaffectthecombustionrateoffuel.Theresultsshowthat,intheswirlingzoneofablastfurnace,thecombustionrateofcoalisgreatlyaffectedbythedistributionofoxygeninthefurnace.Thestudyalsoprovidesreferenceforoptimizingtheoperationofblastfurnace.

Keywords:blastfurnace;swirlingzone;numericalsimulation;oxygen-coalcombustion;flow-solidcouplingInadditiontotheaforementionedfactors,theflow-solidcouplingeffectalsoplaysacrucialroleintheoxygen-coalcombustionprocessintheswirlingzoneofblastfurnace.Theflowfieldinthefurnaceishighlyturbulentandcomplex,andthecoalparticlesarecarriedbythehotgasandmovealongwiththeflowtothecombustionzone.Thecombustionreactionreleasesheat,whichinturnaffectsthegasflowandparticlemotion.Thus,itisimportanttoconsidertheinteractionbetweentheflowandsolidphasesinnumericalsimulation.

Severalstudieshavebeenconductedtoinvestigatetheflow-solidcouplingeffectontheoxygen-coalcombustionprocessintheblastfurnaceswirlingzone.Forexample,Lietal.(2016)adoptedamulti-physicssimulationmethodtoanalyzetheinfluenceofgasflowoncoalcombustion.Theirresultsshowthatthegasflowcanacceleratethecoalcombustionprocessbyenhancingthemixingofcoalparticlesandoxygen.Wangetal.(2018)conductednumericalsimulationandexperimentalstudyontheflow-solidcouplingeffectoncoalcombustionina1/20scalephysicalmodelofblastfurnace.Theirresultsindicatethatthecoalcombustionrateissignificantlyaffectedbythegasflowrateandparticlesize.

Overall,numericalsimulationhasproventobeavaluabletoolforstudyingtheoxygen-coalcombustionprocessintheswirlingzoneofblastfurnace.Byanalyzingthedistributionofoxygenandcoalgas,aswellastheflow-solidcouplingeffect,researcherscanobtaindeeperinsightsintothecombustionmechanismandoptimizetheoperationofblastfurnaceInadditiontonumericalsimulation,experimentalstudieshavealsobeenconductedtoinvestigatetheoxygen-coalcombustionprocessinblastfurnace.AstudybyZhangetal.(2019)usedalab-scalemodeltoexaminetheeffectofparticlesizeandoxygenconcentrationonthecombustionbehaviorofpulverizedcoal.Resultsshowedthatastheparticlesizeincreased,thecombustionratedecreasedduetoadecreaseinthespecificsurfaceareaforreaction.Additionally,astheoxygenconcentrationincreased,thecombustionrateincreasedduetoanincreaseintheavailabilityofoxygenforreaction.

AnotherstudybyLiuetal.(2017)utilizedhigh-speedimagingandthermocouplestovisualizeandmeasurethecombustionprocessofpulverizedcoalinalab-scalemodel.Theyfoundthatthecombustionprocesswashighlydependentonthecoalparticlesizeandinitialtemperature,aswellastheoxygenconcentrationandflowrate.Specifically,smallerparticlesandhigheroxygenconcentrationsresultedinafastercombustionprocessandhigherflametemperature.

Moreover,researchershavealsostudiedtheeffectofvariousadditivesonthecombustionbehaviorofcoalinblastfurnace.Forinstance,astudybyHuangetal.(2018)investigatedtheeffectofaluminumpowderasanadditiveduringcoalcombustion.ResultsindicatedthatthealuminumpowderpromotedtheconversionofcoalchartoCOandenhancedthecombustionefficiencyofcoal.

Inconclusion,theoxygen-coalcombustionprocessintheswirlingzoneofblastfurnaceisacomplexphenomenonthatinvolvesvariousfactors,suchasoxygenconcentration,particlesize,flowrate,andadditives.Numericalsimulationandexperimentalstudieshavehelpedresearchersgainabetterunderstandingofthecombustionmechanismandoptimizetheoperationofblastfurnace.However,furtherresearchisneededtodevelopmoreefficientandsustainablecombustionstrategiesforblastfurnaceWiththeincreasingdemandforsteelproductionworldwide,theefficientandsustainableoperationofblastfurnaceshasbecomeamajorconcernforthesteelindustry.Theoxygen-coalcombustionprocessintheswirlingzoneofblastfurnaceplaysacriticalroleintheoveralloperationofthefurnace.Therefore,itisessentialtounderstandthecombustionmechanismandoptimizetheprocesstoachievemaximumefficiencyandreduceenvironmentalimpacts.

Numericalsimulationandexperimentalstudieshavehelpedresearchersgaininsightsintothecomplexphenomenonofoxygen-coalcombustionintheswirlingzoneofblastfurnace.Thesestudieshaveinvestigatedvariousfactorsaffectingthecombustionprocess,suchasoxygenconcentration,particlesize,flowrate,andadditives.Theresultsofthesestudieshaveidentifiedseveralimportantfactorsthatinfluencethecombustionmechanismandperformanceoftheblastfurnace.

Oneessentialfactorintheoxygen-coalcombustionprocessistheoxygenconcentration.Thehighertheoxygenconcentration,themoreefficientthecombustionprocess.However,thisalsoincreasesthetemperatureandthermalstressoftherefractoryliningofthefurnace.Therefore,itisnecessarytofindabalancebetweentheoxygenconcentrationandrefractoryliningtemperaturetooptimizetheprocess.

Anothercrucialfactorinthecombustionprocessisthecoalparticlesize.Smallercoalparticleshaveahighercombustionratebutalsotendtoformagglomerates,leadingtooperationalissuessuchasmaterialbuild-upandclogging.Largercoalparticleshavealowercombustionratebutarelesspronetoagglomeration.Therefore,optimalcoalparticlesizevariesdependingonthespecificoperationalconditionsofthefurnace.

Theflowrateofoxygenandcoalalsoplaysanimportantroleinthecombustionprocess.Theoptimalflowratedependsonthesizeanddesignofthefurnace,aswellasthepropertiesofthecoalandoxygenusedintheprocess.Flowrateoptimizationcanhelpimprovecombustionefficiencyandreduceemissions,leadingtomoresustainableoperation.

Additivesareanotherimportantfactorinthecombustionprocessofblastfurnaces.Additivescanhelpincreasethecombustionrateandreduceemissions,improvingtheoverallefficiencyoftheprocess.Somecommonlyusedadditivesincludelimestone,dolomite,andquartz.However,theoptimaltypeanddosageofadditivesdependonavarietyoffactors,suchasthepropertiesofthecoalandtheorebeingsmelted.

Despitetheprogressmadeinunderstandingthecombustionmechanismandoptimizingtheoperationofblastfurnace,thereisstillroomforimprovement.Developingmoreeff