钢球磨煤机装载量的消耗
磨煤机钢球的装载量直接影响煤粉的研磨和研碎能力,所以钢球量不能太少,否则对煤的研磨能力作用太小,出粉率低;反之,钢球太多磨煤力距减小同样会影响磨煤的出力,增加电耗。所以并不是钢球装载量大,磨煤机出力就大。从磨煤机内部工作情况来分析,磨煤机出力并不完全随钢球量的增加而增加,当钢球装载量超过最佳值后其磨煤机出力的增加要小于磨煤机功率消耗的增加,磨煤机电耗反而升高。此外,随着磨运行时间的推移,钢球会磨损,钢球量逐渐下降,必须补加新钢球,一般运行2000-3000小时后,应筛选、称量滚筒内不合格的钢球,通常钢球磨损超过40%即可视为不合格。还有大小钢球配比也非常关键,一般情况下小钢球占总量的1/4--1/5效果最佳。这样既能减少钢球之间的空间,同时也可保持钢球一定质量下的冲击力。
Pulverizedcoalballmillloaddirectlyinfluencesthegrindingandgroundcapability,sothesteelballquantitycan''ttoolittle,otherwisetheeffectoncoalgrindingcapacityistoosmall,flourextractionrateislow;Ontheotherhand,theballtoomuchtorque,reducethecoalalsoaffectsgrindingofcoaloutput,increasepowerconsumption.Loadingcapacityisbig,sonotsteelballcoalmilloutputisbig.Fromtheinternalworkingofcoalmill,coalmilloutputisnotentirelyincreaseswiththeincrementofsteelball,whentheballloadingcapacitymorethanthebestvalueincreasedafterthecoalmilloutputlessthantheincreaseofthecoalmillpowerconsumption,coalmillpowerconsumptionincrease.Inaddition,asthemillrunningtime,thesteelballwear,ballquantitygraduallydecline,mustaddnewball,usually2000-3000hoursafteroperation,shouldbeinsubstandardballscreening,weighingroller,usuallysteelballwearmorethan40%canberegardedasunqualified.Alsosizeratioofsteelballiscritical,usuallyasmallsteelballaccountedfor1/4,1/5ofthetotaleffectisbest.Thiscanreducethespacebetweenthesteelball,atthesametimealsocanmaintaintheimpactofthesteelballunderacertainquality.
二、煤质对制粉单耗的影响很大
Second,theinfluenceofcoalqualityforpulverizingunitconsumptionisverylarge
煤质对制粉单耗的影响主要决定于煤的可磨性(原煤被研制成粉的难易程度)和煤的主要性能指标(发热量、挥发份),不同质的煤种,其可磨性系数不同,燃烧工况也不同。前者,直接反映制粉单耗的大小,而后者需要通过一系列的调整来决定制粉单耗的大小。然而,原煤的采购往往不以人的意志为转移,也就是只能在有效的范围内选择,即可控性很小。对我们厂而言,原因就是原煤采购的可操作性很小,可选择的范围受限制,基本上是混杂煤。
Coalqualityimpactonpulverizingunitconsumptionmainlydependsonthegrindabilityofcoal(rawcoaltothedifficultyoftheresearchintopowder)andcoal,themainperformanceindex(calorificvalue,volatile),differentqualityofcoal,whosegrindabilityfactorisdifferent,havedifferentcombustionconditions.Theformer,directlyreflectthesizeofthepulverizingunitconsumption,whilethelatterneedsthroughaseriesofadjustmenttodeterminethesizeofthepulverizingunitconsumption.Procurementofrawcoal,however,areoftennotinman''swilltransfer,alsoisonlywithinthescopeoftheeffectivechoice,namelycontrollabilityissmall.Forourfactory,themaneuverabilityofthereasonisthatrawcoalprocurementisverysmall,canchoosethescopeoftherestrictive,basicallyaremixedwithcoal.
三、运行参数的调整
Three,theadjustmentoftheoperationparameters
有很多运行参数的调整会影响制粉单耗,如煤粉细度、热风开度、再循环开度,均匀给煤等。
Therearealotofrunningparametersadjustmentaffectspulverizingunitconsumption,suchaspulverizedcoalfineness,thehotairopening,therecirculationopening,evenlytocoal,etc.
1、通风量的大小决定煤粉细度,过大和过小都是不利的,通风量太大,系统内风速增加,煤粉磨制一次合格率降低,经粗粉分离器,吊车粗粉被分离出来,经回粉管回到磨煤机,作无益的循环,同时风速过大还会增大管道的磨损,电耗增大;反之若风量过小,不仅使磨煤出力下降,还使干燥能力下降。当通风量很小时,燃料大部分集中在筒体的进口端,由于钢球沿筒体长度是近似均匀分布的,因而在筒体的出口端钢球的能量没有充分被利用,很大一部分能量消耗在金属的磨损和发热上。同时因为酿酒设备筒内风速不高,出口端部分合格煤粉不能被气流带走,带出的仅仅是少量的细煤粉,使得磨煤出力降低。我们知道煤粉细度与燃烧工况有很大的关系,煤粉越细,煤粉在炉膛内燃烧的越充分,反之,煤粉越粗,煤粉在炉膛内燃烧会越不完全,飞灰可燃物所占比例越大,就越不经济。可是,煤粉粗制粉单耗就低,反之,煤粉细制粉单耗就高。这是一对矛盾体,所以,煤粉细度要根据煤质的变化进行不断地调整。要根据炉内的燃烧情况、制粉单耗的大小情况综合考虑,也就是煤粉细度应该控制在煤耗加制粉单耗的最佳经济值上。
1,theventilationratedecidesthesizeofthepulverizedcoalfineness,toobigandtoosmallaredetrimental,ventilationrateistoolarge,thesystemwithinthewindspeedincreases,thequalifiedrateofpulverizedcoalgrindingisreduced,thecoarsepowderseparator,thecoarsepowderisseparatedout,viabacktobacktocoalmill,powdertubesplitcycle,largewindspeedatthesametimewillalsoincreasepipelineabrasion,increasepowerconsumption;Ifvolumeistoosmall,notonlydecreased,theoutputofcoalmillalsodecreaseddryability.Whentheventilationrateisverysmall,mostlyincylinderfuelinletside,duetotheballalongthebarrellengthisapproximatelyuniformdistribution,thusinthecylinderoutletballofenergyisnotfullyused,alargepartofenergyconsumptiononthewearandhotmetal.Cylinderisatthesametimebecausethewindspeedisnothigh,theoutletpartofthequalifiedpulverizedcoalcannotbeflowaway,takeoutisjustasmallamountofpulverizedcoal,pulverizedcoaloutputisreduced.Weknowthatthepulverizedcoalfinenessandcombustionconditionhasalottodo,pulverizedcoal,themorethin,pulverizedcoalcombustioninthefurnaceisfull,ontheotherhand,thepulverizedcoaliscoarse,pulverizedcoalcombustioninsidethechamberofastoveorfurnacecannotcompletely,thegreatertheproportionofflyashcombustiblematerial,thelesstheeconomy.However,coarsepulverizedcoalpulverizingunitconsumptionislow,conversely,finepulverizedcoalpulverizingunitconsumptionishigh.Thisiscontradictory,so,thepulverizedcoalfinenessisadjustedceaselesslyaccordingtocoalqualitychanges.Accordingtothefurnacecombustionconditions,thesizeofthepulverizingunitconsumptionsituationintoaccount,whichispulverizedcoalfinenessshouldcontrolincoalconsumptionandpulverizingunitconsumptionofthebesteconomicvalue.
2、热风的开度对制粉单耗也有很大的影响,特别是露天存放煤的电厂,雨雪天煤的湿度很大,进入磨磨机的湿煤需要热风的干燥,否则,球磨机只工作不出粉,制粉单耗急剧升高,还容易产生压磨。但是,如果热风开度太大,虽然煤的干燥效果得到改善,可同时造成磨筒内的温度不断升高,会产生爆炸的可能性。
2,thehotairopeningtopulverizingunitconsumptionalsohasagreatinfluence,especiallyinopenaircoalpowerplant,coalhumidityisverybigrainandsnowday,intotheslowmachineneedhotairdryingofwetcoal,otherwise,theballmillworkisnotonlythepowderpulverizingunitconsumptionsharplyincreases,alsoeasytoproducepressuregrinding.However,ifthehotairopeningistoobig,althoughcoaldryingeffectimproved,canresultinrisingoftemperatureinthegrindingdrumatthesametime,willproducethepossibilityofexplosion.
3、再循环的开度也会影响到制粉单耗,再循环的开度大,回到球磨机的煤粉就多,使磨煤机的效率下降。反之,回到球磨机的煤粉就少,效率提高,但出粉的质量下降。再循环的开度受煤粉细度的影响。
3,recirculationopeningalsoaffectspulverizingunitconsumption,recycletheopeningisbig,returntothepulverizedcoalballmillismuch,decreasedtheefficiencyofthecoalmill.Instead,gobacktotheballmillcoal,lessefficient,butthequalityofpowder.Recirculationoftheopeningisinfluencedbythefinenessofpulverizedcoal.
4、实现均匀给煤对提高制粉单耗百利而无一害。不能实现均匀给煤,给煤量忽大忽小,时有时无对制粉单耗影响很大,当给煤量减少或断煤,球磨机处于空转或半空转状态,只耗电不出粉。如果给煤量过大,磨筒内空间过小,不能使钢球有足够的落差磨制,严重时会造成压磨。
4,implementation,eventoimprovethesystemforcoalpowderconsumptiontonoharm.Won''tbeabletoachieveeventocoal,coalbigandsmall,whensometimescorrosivepowderconsumptionaffectsisverybig,whencoalisreducedorbrokencoal,millisinidlingorturntheaircondition,powerconsumptionisnotonlythepowder.Ifgivealargeamountofcoal,grindingtubeinsidethespaceistoosmall,can''tmakesteelballthereisenoughgapbetweengrinding,grindingcausedseriouspressure.
5、磨煤机进出口差压的影响,磨煤机进出口差压反映了磨煤机内存煤量的多少。在钢球磨煤机中减少给煤量时将减少磨煤机出力,但是制粉电耗并不按比例减少,从而增加了电耗。增加给煤量可以增加磨煤机中的存煤量,这时磨煤机出力也相应增加,当达到一定极限时,如果继续增加磨煤机中的存煤量,就会出现减少磨煤机出力的现象。其中必然有一个最佳存煤量,最佳存煤量的差压就是当制粉系统电耗最小时的差压。
5,importandexportthedifferentialeffectsofcoalmill,coalmillimportandexportofdifferentialpressurereflectsthememoryofcoalmill.Decreasethecoalinthesteelballcoalmillwillreducethecoalmilloutput,butmillingpowerconsumptiondidnotreduceinproportion,thusincreasingthepowerconsumption.Increasetothequantityofcoalcanincreasetheamountofremainingcoalinthecoalmill,themilloutputalsoincreasesaccordingly,whenreachesacertainlimit,ifcontinuetoincreasetheamountofremainingcoalinthecoalmill,willreduceoutputofthemill.Onemusthavethebestsavecoal,savecoaldifferentialpressureisbestwhenthecoalpulverizingsystemandthemosthoursofthedifferentialpowerconsumption.
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