企业培训_汽机培训教材

GLANDSEALSYSTEM 在汽轮机转子穿过外缸的部位 必须采取措施用以防止外部空气漏入汽缸 从而影响排汽缸的真空 同时也必须防止汽缸内蒸汽漏出汽缸 漏入前轴承箱容易造成油中带水 漏至汽机房破坏汽机房环境 汽轮机的汽封系统就是为了完成这一功能而设置的 Measuresmustbetakenattheportionswheretheturbinerotorpassesthroughtheoutercasingtopreventtheairleakagefromoutsideintothecasingandaffectthevacuityoftheexhausthood Inthemeantime thesteaminsidethecasingmustalsobepreventedfromitsleakagetotheoutside especially tothefrontbearingboxtoleadtoamixingofthelubricationoilwithwaterandtotheturbinehousetodeteriorateitsenvironmentalconditions Theglandsealsystemofasteamturbineisfurnishedjustforsuchapurpose 辅助蒸汽母管 Steamsealcooler Steamsealcooler Steamsealcooler 汽封系统图 本系统是高低压分开供汽的汽封系统 ThepresentsystemisaglandsealsystemcapableofsupplyingsteamtoHPandLPcylinderseparatelydeveloped 系统中主要设备有 高压轴封供汽调节站 低压轴封供汽调节站 高压喷水减温调节站 低压喷水减温调节站 各种截止阀 疏水阀等 连同汽封冷却器 疏水扩容器等设备 共同构成了该机组汽封系统 该系统能够维持汽封供汽母管的压力在0 107 0 11MPa A 之间 供汽温度在121 150 之间 控制部分可根据实际情况接入控制室 通过DCS系统调节各执行机构动作 Thesystemmainlyincludesthefollowingmainequipmentitems HPglandsealsteamsupplyregulatingstation LPglandsealsteamsupplyregulatingstation HPwaterspraydesuperheatingregulatingstation LPwaterspraydesuperheatingregulatingstation variouscut offvalvesanddrainvalves glandsealcoolersanddrainflasktanksetc Itcanexerciseafunctionofmaintainingthesteampressureinsidetheglandsealsteamsupplymainlinebetween0 107Mpaand0 11Mpa thesteamtemperaturebetween121 and150 ThecontrolsignalscanbesenttothecontrolroomaccordingtothespecificcasesandthencontroltheactionofvariousactuatorsthroughtheDCSsystem 转子汽封GlandSealofRotor在汽缸两端装有汽封体和汽封圈 汽封圈上汽封齿环绕转子 表面仅留有为防止在运行过程中发生接触的间隙 Glandcasingsandsealingringsareequippedatbothendsofthecylinderandtheteethonthesealringssurroundtherotorwithaclearancebeingkepttopreventanycontactbetweenthesaidteethandtherotorsurfaceduringtheturbineinoperation 在汽轮机启动时 凝汽器抽真空 汽缸内的压力低于大气压力 供至 A 腔室的汽封蒸汽在一侧通过汽封漏入汽轮机汽缸内 在另一侧漏入 B 腔室 汽封抽汽器正常运行 使 B 腔室维持压力稍低于大气压力 因而空气通过端汽封漏入 B 腔室 形成汽气混合物 通过一个与汽封抽汽器相连的接口 从 B 腔室被抽出 见图1 Duringstartupofthesteamturbine thecondenserisevacuatedandthepressureinthecylindersislowerthantheatmosphericpressure Thesteamsuppliedtothe A chamberoftheglandsealisleakedtothecylinderoftheturbineatonesideandto B chamberatanotherside Iftheairejectorfortheglandsealsisinnormaloperationtomaintainthepressurein B chamberslightlylowerthantheatmosphericpressure theairisleakedintothe B chamberthroughtheglandsealattheend formingasteamandairmixture Thenthemixtureisevacuatedfrom B chamberviaaportconnectedwiththeairejectorfortheglandseals seeFig 1 随着机组负荷的不断提高 高中压缸两端的压力逐渐增加 但因 C 腔室与2号低压加热器 JD2 相连 所以高中压汽封的 A 腔室始终保持送汽状态 由于低压缸压力仍保持一定的真空状态 所以低压汽封的 A 腔室始终保持送汽状态 当除氧器能供汽时 则切到正常运行系统 即由除氧器来供汽 见图2 Withacontinuousincreaseoftheloadofthesteamturbine thepressuresatbothendsofHPandIPcylinderwillgraduallyincrease Asthe C chamberisconnectedtothe2 LPheater JD2 sothe A chambersinHPandIPcylinderisalwayskeptinasteam supplyingstate DuetotheLPcylinderbeingmaintainedatavacuumstate the A chamberofLPglandsealsisalwayskeptinasteam supplyingstate Whenthedeaeratorhasanabilitytosupplysteam thenormaloperationsystemshallbeputintoservice i e supplyingsteambythedeaerator seeFig 2 蒸汽压力温度控制装置SteamPressureandTempController在汽轮机启动和低负荷运行状态下 一般低于40 负荷 辅助汽源经过轴封压力调节阀减压及喷水减温调节阀控制的减温器减温后 向汽封母管供蒸汽 随着负荷不断提高 约40 负荷左右 当除氧器的汽平衡室压力建立起来时 则切换到正常运行系统 即由除氧器来供汽 供汽母管配有热电偶及压力变送器 设计院选配 母管的温度和压力变化是通过与其相连的热电偶和压力变送器传递的 信号传到主控制室 由主控制室DCS系统完成对调节阀的温度和压力控制 Undertheconditionofthesteamturbineoperatinginthestartupstateandatalowload generallylowerthan40 oftheratedload theauxiliarysteamsourceshallsupplysteamtotheglandsealsteammainlineafterthesteampressurehasbeenreducedbytheglandsealsteampressureregulatingvalveandthesteamtemperaturehasbeendesuperheatedbyanattemperatorcontrolledbythewaterspraydesuperheatingregulatingvalve Withacontinuousincreaseoftheload toabout40 oftheratedload whenasteampressureisestablishedinthesteamequilibriumchamberofthedeaerator thenormaloperationsystemshallbeputintooperation i e thesteamtotheglandsealsshallbesuppliedbythedeaerator Thesteamsupplymainlineshallbeequippedwiththermocouplesandpressuretransmitters selectedbyanelectric powerdesigninginstitute ThesignalsshowingthechangeofsteamtemperatureandpressureinthemainlinearetransmittedbythethermocouplesandpressuretransmitterstothemaincontrolroomandthentheDCScontrolsystemshallexerciseacontroloverthesteamtemperatureandpressurebyuseoftheregulatingvalvebasedonthesignals 汽封压力调节阀能在所有运行条件下以其DCS系统的给定压力向各汽封供汽 轴封送汽调节阀压力给定值为0 107 0 11MPa A 因母管压损未知可按实际情况调整 TheglandsealsteampressureregulatingvalveshallsupplysteamtovariousglandsealsatapressuresetbytheDCScontrolsystematalltheoperatingconditions Theglandsealsteampressuresetpointbytheregulatingvalverangesfrom0 107 0 11MPa A duetothepressurelossinthemainlinebeingunknown onecanmakeanadjustmentaccordingtothespecificcase 供汽母管蒸汽温度主要是由减温器来控制的 减温水来自于凝结水泵 减温水量是由减温水调节阀来控制的 温度信号取自供汽母管的温度 将温度信号转换为4 20mA电信号送到主控制室 由DCS系统来控制减温水调节阀的执行机构 使供汽母管蒸汽温度控制在121 150 之间 Thesteamtemperatureinthesteamsupplymainlineismainlycontrolledbythedesuperheaterwiththedesuperheatingwatercomingfromthecondenstatewaterpumpandthedesuperheatingwaterquantitybeingcontrolledbythedesuperheatingwaterregulatingvalve Thetemperaturesignalisobtainedfromthesteamsupplymainlineandthenconvertedintoa4 20mAelectronicsignalwhichissenttothemaincontrolroom Basedontheelectronicsignal theDCScontrolsystemtakescontrolovertheactuatorofthedesuperheatingwaterregulatingvalve maintainingthesteamtemperatureinthesteamsupplymainlinebetween121 and150 汽封冷却器GlandCooler汽封冷却器以稍低于大气压力即0 095MPa A 的压力接收阀杆及汽封 B 腔室的漏汽 因此保证 B 腔室一直保持负压 Theglandsealcoolerreceivesthesteamleakagefromthestemsandtheglandseal B chamberbyoperatingatapressureof0 095MPa A slightlylowerthantheatmosphericpressure thuskeepingthe B chamberbeingalwaysatanegativepressure 蒸汽过滤器SteamFilter为了防止外部物质进入汽封和引起转子的损坏 在每个汽封的供汽管道中使用了蒸汽过滤器 过滤器 Y 形支管是水平安装或置于管道的顶部 所以能够自行排空 Topreventforeignmattersfromenteringintotheglandsealsandcausingadamagetotherotor thesteamfiltersareusedineverysteamsupplypipelinesoftheglandsealsandthe Y shapedbranchpipesshallbeinstalledhorizontallyorplacedonthetopofthepipes thusensuringanairventbythefiltersthemselves 汽封系统的运行OperationofGlandSystem 冷态启动Cold stateStartup1 在汽轮机和进汽管道所有疏水阀打开的情况下 投入盘车 Undertheconditionthatallthedrainwatervalvesonthesteamturbineandsteamintakingpipelinesareopened theturninggearshallbeputintoservice 2 建立通过凝汽器的水循环 Establishawatercirculationthroughthecondenser 3 启动凝结水泵并建立通过汽封抽汽器的冷却水流 Startupthecondensatewaterpumpandestablishacoolingwaterflowratethroughtheairejectoroftheglandseals 4 开启汽封抽汽器水室上的放气口 直至全部残留气体排入大气 Opentheairventonthewaterboxoftheairejectoroftheglandsealsuntilalltheresidualgasisdischargedtotheatmosphere 5 确认疏水扩容器壳体的疏水系统对凝汽器是打开的 Makesurethatthedrainsysteminsidetheenclosureofthedrainwaterflashtankisopenedtothecondenser 6 确认汽封抽汽器水位报警器在运行中 且仪表截止阀是打开的 Makesurethatthewaterlevelalarmoftheairejectorfortheglandsealsisinoperationandthecut offvalvesoftheinstrumentsareopened 7 确认每个汽封压力 温度调节站及旁路阀处于关闭状态 Makesurethateveryglandsealsteampressureandtemperatureregulatorstationsandbypassvalvesareintheclosingstate 8 确认启动汽源温度必须具有不小于14 的过热度 Makesurethatthetemperatureofthestartupsteamsourcecompulsorilyhasadegreeofsuperheatofnotlessthan14 9 确认调节阀入口的供汽管道中无水 Makesurethatthereisnowaterinthesteamsupplypipelinetotheinletoftheregulatingvalve 10 启每个调节阀两侧的手动截止阀 Openthemanually operatedvalvesatbothsidesofeachregulatingvalves 11 汽封系统在冷态启动状态时 辅助汽源向各个汽缸前后汽封供汽 蒸汽通过轴封压力调节阀减压 再通过减温器减温到121 150 向高低压前后轴封供汽 如果除氧器能供汽 则切到正常运行系统 Duringacold statestartupoftheglandsealsystem theauxiliarysteamsourceshallprovidesteamtotheglandsealsinthefrontandattherearofvariouscylinders Thesteampressureisreducedbytheglandsealsteampressureregulatingvalveandthesteamtemperatureisdesuperheatedto121 and150 byanattemperator Then thesteamissuppliedtotheHPandLPfrontandrearglandseals Ifthedeaeratorhasanabilitytosupplythesteam thenthenormaloperationsystemshallbeputintoservice 12 当汽封供汽母管压力建立并暖管后 立即启动汽封抽汽器 Whenthesteampressureinthesteamsupplymainlineoftheglandsealsisestablishedandthesaidmainlineiswarmedup oneshallimmediatelystartuptheairejectorfortheglandseals 13 确认汽缸的每个汽封腔室均有低度真空 Makesurethateachchamberoftheglandsealsforthecylindershasavacuityatalowdegree 14 确认各汽封腔室内蒸汽没有漏入大气 如果发现漏汽 则提高汽封抽汽器真空 或调整压力调节阀或各送汽支路上的送汽截止阀 调节各截止阀开度 以降低汽封母管的蒸汽压力 直至停止向外部漏汽 Makesurethatthesteaminvariousglandsealchambersdoesnotleaktotheatmosphere Ifanyleakageofsteamisfound thevacuitymaintainedbyuseoftheairejectorshallbeenhancedorthepressureregulatingvalveorthecut offvalvesonvariousbranchlinesforsteamsupplyshallbeadjustedortheopeningdegreesofvariouscut offvalvesshallberegulatedtoreducethesteampressureintheglandsealsteammainlineuntilthesaidleakageofsteamtotheoutsideisstopped 15 检查汽封供汽母管的温度 检查高压缸内壁温度与汽封腔室内蒸汽温度之差值 确保差值小于110 确保后汽封送汽腔室内蒸汽温度在121 150 之间 检查汽封蒸汽管路疏水是否通畅 Inspectthetemperatureintheglandsealsteamsupplymainline inspectthetemperaturedifferencebetweentheinnerwalltemperatureoftheHPcylinderandsteamintheglandsealchambers ensurethesaiddifferencetobelessthan110 andthesteamtemperatureintherearglandsealsteamsupplychambertobebetween121 to150 Inspecttheglandsealsteampipelinestoseewhetherthedraininsideflowsfreely 16 关闭凝汽器的真空破坏门 启动抽气设备 并在凝汽器内建立尽可能高的真空 在每个汽封建立起最大流量之前 所需的汽封蒸汽量随凝汽器真空的改善而增加 Closethevacuumbreakingvalve startuptheairejectorequipmentandestablishavacuityashighaspossibleinthecondenser Priortoanestablishmentofamaximumflowrateineachglandseals thesteamamountnecessaryfortheglandsealswillincreasewithanincreaseofthevacuityinthecondenser 17 当负荷逐渐增加时 来自除氧器的蒸汽可以满足高 低汽封供汽时 则辅助汽源供汽切换到除氧器供汽 这样高中压汽封系统与低压汽封系统相互独立 整个系统相对稳定 WhentheloadgraduallyincreasesandthesteamflowratefromthedeaeratorcanmeetthesteamamountrequiredbytheHPandIPglandsealsystem thesteamcanbeswitchedoverfromsuppliedbytheauxiliarysteamsourcetosuppliedbythedeaerator Insuchacase theHPandIPglandsealsystemareindependentfromtheLPglandsealsystemandthewholesystemisrelativelystable 控制降负荷ControlLoadReduction 在控制降负荷时 汽封母管的蒸汽压力高于0 107MPa A 则汽封系统维持正常状态 高 低压汽封供汽由除氧器供给 当汽封母管压力低于0 107MPa A 时 即除氧器的汽源不能保证母管压力时 改由辅助汽源供汽 Whentheloadreductioniscontrolledandthesteampressureintheglandsealsteammainlineishigherthan0 107Mpa A theglandsealsystemiskeptinanormaloperationstateandHPandLPglandsealsteamissuppliedbythedeaerator Whenthesteampressureintheglandsealsteammainlineislowerthan0 107Mpa A i e thesteamfromthedeaeratorcannotmaintainthepressureinthemainline thenthesteamshallbesuppliedbyanauxiliarysteamsource 汽轮机停机TurbineShutdown 只要存在着保持汽缸内真空的必要 就必须向汽轮机各汽封提供密封蒸汽 在凝汽器的抽气设备停止运行和凝汽器的真空完全消失以前 不得切断汽封供汽 否则冷空气流入会使转子表面金属急剧冷却 而且还会导致热的静止的汽封体变形 Aslongasaneedforkeepingavacuityinthecylindersexists oneshallsupplysteamtovariousglandsealsoftheturbine Priortothestoppageoftheairextractionequipmentofthecondenserandafulllossofvacuityinthecondenser thesteamsuppliedtotheglandsealsshallnotbecutoff otherwise coldairenteringintothesteamturbinewouldcauseanabruptcoolingoftherotorsurfacemetalandalsoresultinadeformationofthehotandstillglandcasings 汽轮机停机顺序ShutdownSequence 1 在机组盘车和汽封供汽来自外部汽源的情况下 确认凝汽器真空已完全消失 Undertheconditionthatthesteamformaintainingtheturbineturningandtheglandsealsisfromthesteamsourceattheoutside oneshallmakesurethatthevacuityinthecondenserhasbeenfullylost 2 关闭汽封冷却器风机 Closethefanoftheglandsealcooler 3 关闭各汽封压力调节阀两侧的手动截止阀 Closevariousmanually operatedcut offvalvesatbothsidesoftheglandsealsteampressureregulatingvalve 在切断汽封冷却器的风机后 应立即关闭上述阀门 在汽封体内无真空的情况下 汽封供汽的投入导致蒸汽漏入大气 这些蒸汽会进入润滑油中 并凝结成为污染杂质 积存在油箱中 Afterthefanoftheglandsealcoolerhasbeenstopped oneshallimmediatelyclosealltheabove mentionedvalves Undertheconditionthatthesealcasingisatzerovacuity iftheglandsealsaresuppliedwithsteam thelatterwillbeescapedtotheatmosphereandalsotothebearingbox mixedwiththelubricationoilandcoagulatedtopollutantsanddepositedintheoiltank 热态启动Hot stateStartup热态启动状态 机组转子温度接近满负荷运行工况下的转子温度 此时所有阀门状态同冷态启动 只是增加一股热态启动汽源 P 1 0MPa T 450 通过高温电动 手动截止阀后 向图2中的高压前汽封的 D 腔室送汽 其它同冷态启动送汽 如果除氧器能供汽 则切到正常运行系统 Hot statestartupstatus therotortemperatureofthesteamturbineshallapproximatetothatatthefull loadoperationcondition Insuchacase thestatesofal