南师大锅炉原理课件4-2 磨煤设备及其特性

2025/6/221Pulverizerdesignrequirements

Manydifferentpulverizerdesignshavebeenappliedtocoalfiring.Successfuldesignshavemetcertainfundamentalgoalsandrequirements:optimumfinenessfordesigncoalsovertheentirepulverizeroperatingrange,rapidresponsetoloadchanges,stableandsafeoperationovertheentireloadrange,continuousserviceoverlongoperatingperiods,acceptablemaintenancerequirements,particularlygrindingelements,overthepulverizerlife,abilitytohandlevariationsincoalproperties,easeofmaintenance(minimumnumberofmovingpartsandadequateaccess),andminimumbuildingvolume.4.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2025/6/2224.2Pulverizeranditsproperties

§4-2磨煤设备及其特性1.MechanismandclassificationofPulverizer磨煤机的作用机理和分类Pulverizeristhemainequipmentofpulverizationsystem,whoseworkingcharacteristicsisveryimportanttocoalfineness,capacity,electricityconsumption,metalconsumption,etc. 磨煤机是煤粉制备系统中主要设备，其工作性能对煤粉细度、煤粉出力、磨煤电耗、磨煤机金属耗量和干燥煤粉的能力等都有很大的影响。2025/6/223Grindingmechanism破碎机理：压碎

crush

击碎impact,hit,punch研碎attrition,trituration,whichisdominantsizereductionmechanism4.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2025/6/2244.2Pulverizeranditsproperties

§4-2磨煤设备及其特性Basedonrotatevelocity根据转速分为：LowspeedPulverizer:n=16~20r/minball-and-tube

mill球磨机ModeratespeedPulverizer:n=50~300r/min平盘式磨煤机、环球式、碗式、MPS磨煤机等HighspeedPulverizer:n=500~1500r/min风扇式、锤击式2025/6/2254.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2.Ball-and-tubemill球磨机(pp.48)1)Workingfundamental工作原理(图4-2)Thecylinderislinedwithwearresistant material(衬板)contouredtoenhancethe actionoftumblingballs.Theballsfill25to30%ofthecylindervolume.Therotationalspeedis80%ofthatatwhichcentrifugalforce(离心力)

wouldovercomegravityandcausetheballstoclingtotheshellwall.Grindingiscausedbythetumblingactionwhichtrapscoalparticlesbetweenballsastheyimpact.2025/6/2264.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2.Ball-and-tubemill球磨机筒式球磨机是中间储仓式煤粉制备系统中主要设备，其筒体内壁装设波浪形铸钢护板，内径Dn=2~4m，筒长L=3~10m,筒内装有d=25~60mm的钢锻、钢球。筒式球磨机转速随筒体直径的不同而变化，转速一般为16~20rpm。转速过快时，钢球在离心力作用下会紧贴筒壁运动而不下落，起不到磨煤的作用。筒式球磨机的工作转速必须小于临界转速。2025/6/2274.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2.Ball-and-tubemill球磨机2)Influencingfactors影响球磨机工作的主要因素Criticalrotaryspeed临界转速nlj

workingrotaryspeed,n2025/6/2284.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2.Ball-and-tubemill球磨机2)Influencingfactors影响球磨机工作的主要因素Fillingfactor钢球充满系数=0.2~0.32025/6/2294.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2.Ball-and-tubemill球磨机2)Influencingfactors影响球磨机工作的主要因素BallDiameter钢球直径根据煤种及磨机工作条件，将40,50,60mm的钢球搭配使用Wearresistantmaterial护甲，衬板2025/6/22104.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2.Ball-and-tubemill球磨机2)Influencingfactors影响球磨机工作的主要因素Airflowrateintheballmill通风量磨内载煤量最佳载煤量磨机出力2025/6/22114.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2.Ball-and-tubemill球磨机3)Millcapacityandconsumptionelectricalpower球磨机出力Bm和消耗电功率Pdw磨机单位电耗Unitpowerconsumption2025/6/22124.2Pulverizeranditsproperties

§4-2磨煤设备及其特性4)球磨机的特点优点煤种适应性广结构简单，故障少运行安全可靠缺点设备笨重，金属耗量大初投资及运行电耗，金属损耗高影响噪音大低负荷下运行不经济Ball-and-tubemillshavelargelybeensupplanted(替代)byverticalair-sweptpulverizersfornewboilers.Theytypicallyrequirelargerbuildingvolumeandhigherspecificpowerconsumptionthantheverticalair-sweptpulverizers.Theyarealsomoredifficulttocontrolandhavehighermetalwearrates.Theyare,however,wellsuitedforgrindingextremelyabrasive,lowmoisture,anddifficultmaterialssuchaspetroleumcoke.Theirlongcoalresidencetimemakesthemeffectiveforfinegrinding.2025/6/22132.Ball-and-tubemillsystem球磨机系统Ball-and-tubemillsmaybeeithersingleordoubleendsystem.1)singleend单进单出钢球磨煤机(图4-5)2)doubleend双进双出钢球磨煤机(图4-9,fig.13-8)4.2Pulverizeranditsproperties

§4-2磨煤设备及其特性coalPC2025/6/2214WorkingprocessofSingleinletandoutletmill4.2Pulverizeranditsproperties

§4-2磨煤设备及其特性classifierCoalfeedermillbinfurnacecycloneAPH2025/6/2215doubleend双进双出钢球磨煤机WorkingprinciplealsoreferFig.4-4(pp51,pp.57-58)4.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2025/6/22164.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2.Ball-and-tubemill球磨机Theoldestpulverizerdesignstillinfrequentuseistheball-and-tubemill.Thisisahorizontalcylinder,partlyfilledwithsmalldiameterballs(Fig.8).Thecylinderislinedwithwearresistantmaterialcontouredenhancetheactionofthetumblingballs.Theballsfill25to30%ofthecylindervolume.Therotationalspeedis80%ofthatatwhichcentrifugalforcewouldovercomegravityandcausetheballstoclingtotheshellwall.Grindingiscausedbythetumblingactionwhichtrapscoalparticlesbetweenballsastheyimpact.2025/6/22174.2Pulverizeranditsproperties

§4-2磨煤设备及其特性Ball-and-tubemillshavelargelybeensupplanted(替代)byverticalair-sweptpulverizersfornewboilers.Theytypicallyrequirelargerbuildingvolumeandhigherspecificpowerconsumptionthantheverticalair-sweptpulverizers.Theyarealsomoredifficulttocontrolandhavehighermetalwearrates.however,Theyarestillusedinmid-/smallerlevelboiler.(中小规模仍有使用)Theyare,wellsuitedforgrindingextremelyabrasive,lowmoisture,anddifficultmaterialssuchaspetroleumcoke.Theirlongcoalresidencetimemakesthemeffectiveforfinegrinding.2025/6/22184.2Pulverizeranditsproperties

§4-2磨煤设备及其特性3.ModeratespeedPulverizer中速磨煤机电厂使用的中速磨煤机主要有四种类型（pp.51-52）：辊－盘式，平盘式(图4-5)辊－碗式，碗式(图4-6)辊－环式，MPS(图4-7)球－环式，E型(图4-8)Roll-platetypeRoll-bowltypeRoll-ringtypeBall-ringtype2025/6/22194.2Pulverizeranditsproperties

§4-2磨煤设备及其特性Roll-platetype1－reductiongearbox减速齿轮箱2－grindingplate磨盘3－grindroll磨辊4－spring加压弹簧5-coaldroppipe落煤管6-classifier分离器7－outlet气粉混合物出口8－airring风环2025/6/22204.2Pulverizeranditsproperties

§4-2磨煤设备及其特性Roll-bowltype1－reductiongearbox减速箱2－bowl浅沿磨碗3－airring风环4－Pressurizedvessel加压缸5－outlet气粉混合物出口6－coalinlet原煤入口8－classifier分离器9－roll磨辊10－hotairinlet热风进口11－scraper杂物刮板12－discharge杂物排放管2025/6/22214.2Pulverizeranditsproperties

§4-2磨煤设备及其特性Ball-ringtype1－guideblock导块2－clampring压紧环3－upgrindingring上磨环4－ball钢球5－downgrindingring下磨环6－support轭架7－pyritebox石子煤箱8－adjustablegate活门9－spring压紧弹簧10－hotairinlet热风进口11－pcoutlet煤粉出口12－rawcoalinlet原煤进口2025/6/22224.2Pulverizeranditsproperties

§4-2磨煤设备及其特性Roll-ringtype1－springhold-downring弹簧压紧环2－spring弹簧3－junkring压环4－roller滚子5－pressingblock压块6－roller辊子7－grindingring磨环8－grindingplate磨盘9－nozzlering喷嘴环10－tighteningwirerope拉紧钢丝绳2025/6/22234.2Pulverizeranditsproperties

§4-2磨煤设备及其特性Workingprinciple驱动装置研磨部件干燥分离煤粉分离及分配2025/6/22244.2Pulverizeranditsproperties

§4-2磨煤设备及其特性影响中速磨煤机工作的主要因素转速通风量1.5-2.2kg风/kg粉风环气流速度：E型磨：70-90m/s;碗磨：40-45m/s碾磨压力：需及时调整燃料性质水分：<12%哈氏可磨性系数：≥502025/6/22254.2Pulverizeranditsproperties

§4-2磨煤设备及其特性3.ModeratespeedPulverizer

Advantages优点结构紧凑，占地面积小，重量轻，投资省Lowernoise运行噪声小，电耗及金属磨耗低煤粉均匀性指数高，特别适宜变负荷运行Disadvantages缺点Complexstructure结构复杂Maintainonschedule需严格地定期检修、维护2025/6/2226Thismachineoperatesatabout600rpmandgrindsbybothimpactandattrition.Coalandheatedairenterattheimpactsectionforinitialsizereductionthenpassbetweenmovingandstationarypartsforfinalsizereduction(Fig.6).Atthefinalstage,anexhausterfandrawstheairandcoalthroughthemillfordryingandtransport.4.2Pulverizeranditsproperties

§4-2磨煤设备及其特性4.HighspeedPulverizer高速磨煤机2025/6/22274.2Pulverizeranditsproperties

§4-2磨煤设备及其特性Thereisnoclassifierandthedesignreliesupontheactionoftherotorandstatortoachievesizecontrolinasinglepassofthecoal.Thecoalpassesthroughquicklysothereislittlestorageinthemill.Thispulverizerislimitedtocoalswithmoisturecontentof20%orlessbecauseoftheshortresidencetimefordrying.2025/6/2228BeatermillsareusedoutsideNorthAmerica(Fig.7).Thesearesimilarinsomerespectstotheattritionmillsdescribedabove.4.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2025/6/2229BeatermillsThesemillsareusedforgrindinganddryingthefossilfuelsreferredtoasbrowncoals.Theseareverylowgradelignitetypecoalswithhighashandmoisturecontentsandlowheatingvalues.Moisturecontentofbrowncoaloftenexceeds50%andcombinedashandmoisturecontentsmayexceed60%.

Beatermillsgrindbyimpactandattritionwithveryrapiddrying.Theyachievedryingdespiteshortresidencetimebyreplacingprimaryairwithextremelyhightemperaturegasextractedfromtheupperfurnaceattemperaturesabout1900F(1038C).Coalismixedwiththegasstreamaheadofthemillforinitialdryingtoreducetheinlettemperature.Thefinalstageisthefansectionwhichmaintainsanegativepressureinthemillatalltimes.Beatermillsoperateatvariablespeedtocontrolgrindingperformanceatvaryingcoalfeedrates.4.2Pulverizeranditsproperties

§4-2磨煤设备及其特性2025/6/22304.HighspeedPulverizer高速磨煤机Fan-typehighspeedpulverizer风扇式磨煤机ShaftwelltypeHighspeedPulverizer竖井式磨煤机4.2Pulverizeranditsproperties

§4-2磨煤设备及其特性1－机壳2－冲击板3－叶轮4－燃料进口5－出口6－轴7－轴承箱8－联轴节

2025/6/22314.2Pulverizeranditsproperties

§4-2磨煤设备及其特性Fan-typehighspeedpulverizer风扇式磨煤机Exhauster,with750~1500r/minoftherotatingspeedcanproducehighpressureof15