汽機培訓教材9

汽機培訓教材92024/3/29汽機培訓教材9在汽輪機轉(zhuǎn)子穿過外缸的部位，必須采取措施用以防止外部空氣漏入汽缸，從而影響排汽缸的真空，同時也必須防止汽缸內(nèi)蒸汽漏出汽缸，漏入前軸承箱容易造成油中帶水，漏至汽機房破壞汽機房環(huán)境。汽輪機的汽封系統(tǒng)就是為了完成這一功能而設置的。Measuresmustbetakenattheportionswheretheturbinerotorpassesthroughtheoutercasingtopreventtheairleakagefromoutsideintothecasingandaffectthevacuityoftheexhausthood.Inthemeantime,thesteaminsidethecasingmustalsobepreventedfromitsleakagetotheoutside,especially,tothefrontbearingboxtoleadtoamixingofthelubricationoilwithwaterandtotheturbinehousetodeteriorateitsenvironmentalconditions.Theglandsealsystemofasteamturbineisfurnishedjustforsuchapurpose.

汽機培訓教材9輔助蒸汽母管Steamsealcooler汽機培訓教材9Steamsealcooler汽機培訓教材9Steamsealcooler汽封系統(tǒng)圖汽機培訓教材9本系統(tǒng)是高低壓分開供汽的汽封系統(tǒng).ThepresentsystemisaglandsealsystemcapableofsupplyingsteamtoHPandLPcylinderseparatelydeveloped.

汽機培訓教材9系統(tǒng)中主要設備有：高壓軸封供汽調(diào)節(jié)站、低壓軸封供汽調(diào)節(jié)站、高壓噴水減溫調(diào)節(jié)站、低壓噴水減溫調(diào)節(jié)站、各種截止閥、疏水閥等，連同汽封冷卻器、疏水擴容器等設備，共同構(gòu)成了該機組汽封系統(tǒng)。該系統(tǒng)能夠維持汽封供汽母管的壓力在0.107～0.11MPa(A)之間，供汽溫度在121～150℃之間，控制部分可根據(jù)實際情況接入控制室，通過DCS系統(tǒng)調(diào)節(jié)各執(zhí)行機構(gòu)動作。Thesystemmainlyincludesthefollowingmainequipmentitems:HPglandsealsteamsupplyregulatingstation,LPglandsealsteamsupplyregulatingstation,HPwaterspraydesuperheatingregulatingstation,LPwaterspraydesuperheatingregulatingstation,variouscut-offvalvesanddrainvalves,glandsealcoolersanddrainflasktanksetc.Itcanexerciseafunctionofmaintainingthesteampressureinsidetheglandsealsteamsupplymainlinebetween0.107Mpaand0.11Mpa,thesteamtemperaturebetween121℃and150℃.ThecontrolsignalscanbesenttothecontrolroomaccordingtothespecificcasesandthencontroltheactionofvariousactuatorsthroughtheDCSsystem.汽機培訓教材9轉(zhuǎn)子汽封GlandSealofRotor在汽缸兩端裝有汽封體和汽封圈，汽封圈上汽封齒環(huán)繞轉(zhuǎn)子，表面僅留有為防止在運行過程中發(fā)生接觸的間隙。Glandcasingsandsealingringsareequippedatbothendsofthecylinderandtheteethonthesealringssurroundtherotorwithaclearancebeingkepttopreventanycontactbetweenthesaidteethandtherotorsurfaceduringtheturbineinoperation.在汽輪機啟動時，凝汽器抽真空，汽缸內(nèi)的壓力低于大氣壓力，供至“A”腔室的汽封蒸汽在一側(cè)通過汽封漏入汽輪機汽缸內(nèi)，在另一側(cè)漏入“B”腔室，汽封抽汽器正常運行，使“B”腔室維持壓力稍低于大氣壓力，因而空氣通過端汽封漏入“B”腔室，形成汽氣混合物，通過一個與汽封抽汽器相連的接口，從“B”腔室被抽出。(見圖1)Duringstartupofthesteamturbine,thecondenserisevacuatedandthepressureinthecylindersislowerthantheatmosphericpressure.Thesteamsuppliedtothe“A”chamberoftheglandsealisleakedtothecylinderoftheturbineatonesideandto“B”chamberatanotherside.Iftheairejectorfortheglandsealsisinnormaloperationtomaintainthepressurein“B”chamberslightlylowerthantheatmosphericpressure,theairisleakedintothe“B”chamberthroughtheglandsealattheend,formingasteamandairmixture.Thenthemixtureisevacuatedfrom“B”chamberviaaportconnectedwiththeairejectorfortheglandseals(seeFig.1).汽機培訓教材9汽機培訓教材9隨著機組負荷的不斷提高，高中壓缸兩端的壓力逐漸增加，但因“C”腔室與2號低壓加熱器(JD2)相連，所以高中壓汽封的“A”腔室始終保持送汽狀態(tài)；由于低壓缸壓力仍保持一定的真空狀態(tài)，所以低壓汽封的“A”腔室始終保持送汽狀態(tài)。當除氧器能供汽時，則切到正常運行系統(tǒng)，即由除氧器來供汽(見圖2)。Withacontinuousincreaseoftheloadofthesteamturbine,thepressuresatbothendsofHPandIPcylinderwillgraduallyincrease.Asthe“C”chamberisconnectedtothe2#LPheater(JD2),sothe“A”chambersinHPandIPcylinderisalwayskeptinasteam-supplyingstate.DuetotheLPcylinderbeingmaintainedatavacuumstate,the“A”chamberofLPglandsealsisalwayskeptinasteam-supplyingstate.Whenthedeaeratorhasanabilitytosupplysteam,thenormaloperationsystemshallbeputintoservice,i.e.supplyingsteambythedeaerator(seeFig.2).汽機培訓教材9汽機培訓教材9蒸汽壓力溫度控制裝置SteamPressureandTempController在汽輪機啟動和低負荷運行狀態(tài)下（一般低于40%負荷），輔助汽源經(jīng)過軸封壓力調(diào)節(jié)閥減壓及噴水減溫調(diào)節(jié)閥控制的減溫器減溫后，向汽封母管供蒸汽。隨著負荷不斷提高(約40%負荷左右)，當除氧器的汽平衡室壓力建立起來時，則切換到正常運行系統(tǒng)，即由除氧器來供汽。供汽母管配有熱電偶及壓力變送器(設計院選配)，母管的溫度和壓力變化是通過與其相連的熱電偶和壓力變送器傳遞的，信號傳到主控制室，由主控制室DCS系統(tǒng)完成對調(diào)節(jié)閥的溫度和壓力控制。Undertheconditionofthesteamturbineoperatinginthestartupstateandatalowload(generallylowerthan40%oftheratedload),theauxiliarysteamsourceshallsupplysteamtotheglandsealsteammainlineafterthesteampressurehasbeenreducedbytheglandsealsteampressureregulatingvalveandthesteamtemperaturehasbeendesuperheatedbyanattemperatorcontrolledbythewaterspraydesuperheatingregulatingvalve.Withacontinuousincreaseoftheload(toabout40%oftheratedload),whenasteampressureisestablishedinthesteamequilibriumchamberofthedeaerator,thenormaloperationsystemshallbeputintooperation,i.e.thesteamtotheglandsealsshallbesuppliedbythedeaerator.Thesteamsupplymainlineshallbeequippedwiththermocouplesandpressuretransmitters(selectedbyanelectric-powerdesigninginstitute).ThesignalsshowingthechangeofsteamtemperatureandpressureinthemainlinearetransmittedbythethermocouplesandpressuretransmitterstothemaincontrolroomandthentheDCScontrolsystemshallexerciseacontroloverthesteamtemperatureandpressurebyuseoftheregulatingvalvebasedonthesignals.汽機培訓教材9汽封壓力調(diào)節(jié)閥能在所有運行條件下以其DCS系統(tǒng)的給定壓力向各汽封供汽。軸封送汽調(diào)節(jié)閥壓力給定值為0.107～0.11MPa（A）。（因母管壓損未知可按實際情況調(diào)整）TheglandsealsteampressureregulatingvalveshallsupplysteamtovariousglandsealsatapressuresetbytheDCScontrolsystematalltheoperatingconditions.Theglandsealsteampressuresetpointbytheregulatingvalverangesfrom0.107～0.11MPa（A）(duetothepressurelossinthemainlinebeingunknown,onecanmakeanadjustmentaccordingtothespecificcase).汽機培訓教材9供汽母管蒸汽溫度主要是由減溫器來控制的，減溫水來自于凝結(jié)水泵，減溫水量是由減溫水調(diào)節(jié)閥來控制的，溫度信號取自供汽母管的溫度，將溫度信號轉(zhuǎn)換為4～20mA電信號送到主控制室，由DCS系統(tǒng)來控制減溫水調(diào)節(jié)閥的執(zhí)行機構(gòu)，使供汽母管蒸汽溫度控制在121～150℃之間。Thesteamtemperatureinthesteamsupplymainlineismainlycontrolledbythedesuperheaterwiththedesuperheatingwatercomingfromthecondenstatewaterpumpandthedesuperheatingwaterquantitybeingcontrolledbythedesuperheatingwaterregulatingvalve.Thetemperaturesignalisobtainedfromthesteamsupplymainlineandthenconvertedintoa4～20mAelectronicsignalwhichissenttothemaincontrolroom.Basedontheelectronicsignal,theDCScontrolsystemtakescontrolovertheactuatorofthedesuperheatingwaterregulatingvalve,maintainingthesteamtemperatureinthesteamsupplymainlinebetween121℃and150℃.汽機培訓教材9汽封冷卻器GlandCooler汽封冷卻器以稍低于大氣壓力即0.095MPa（A）的壓力接收閥桿及汽封“B”腔室的漏汽，因此保證“B”腔室一直保持負壓。Theglandsealcoolerreceivesthesteamleakagefromthestemsandtheglandseal“B”chamberbyoperatingatapressureof0.095MPa（A）slightlylowerthantheatmosphericpressure,thuskeepingthe“B”chamberbeingalwaysatanegativepressure.汽機培訓教材9蒸汽過濾器SteamFilter為了防止外部物質(zhì)進入汽封和引起轉(zhuǎn)子的損壞，在每個汽封的供汽管道中使用了蒸汽過濾器，過濾器“Y”形支管是水平安裝或置于管道的頂部，所以能夠自行排空。Topreventforeignmattersfromenteringintotheglandsealsandcausingadamagetotherotor,thesteamfiltersareusedineverysteamsupplypipelinesoftheglandsealsandthe“Y”-shapedbranchpipesshallbeinstalledhorizontallyorplacedonthetopofthepipes,thusensuringanairventbythefiltersthemselves.汽機培訓教材9汽封系統(tǒng)的運行OperationofGlandSystem冷態(tài)啟動Cold-stateStartup1.在汽輪機和進汽管道所有疏水閥打開的情況下，投入盤車。Undertheconditionthatallthedrainwatervalvesonthesteamturbineandsteamintakingpipelinesareopened,theturninggearshallbeputintoservice.汽機培訓教材92.建立通過凝汽器的水循環(huán)。Establishawatercirculationthroughthecondenser.3.啟動凝結(jié)水泵并建立通過汽封抽汽器的冷卻水流。Startupthecondensatewaterpumpandestablishacoolingwaterflowratethroughtheairejectoroftheglandseals.汽機培訓教材94.開啟汽封抽汽器水室上的放氣口，直至全部殘留氣體排入大氣。Opentheairventonthewaterboxoftheairejectoroftheglandsealsuntilalltheresidualgasisdischargedtotheatmosphere.5.確認疏水擴容器殼體的疏水系統(tǒng)對凝汽器是打開的。Makesurethatthedrainsysteminsidetheenclosureofthedrainwaterflashtankisopenedtothecondenser.6.確認汽封抽汽器水位報警器在運行中，且儀表截止閥是打開的。Makesurethatthewaterlevelalarmoftheairejectorfortheglandsealsisinoperationandthecut-offvalvesoftheinstrumentsareopened.汽機培訓教材97.確認每個汽封壓力、溫度調(diào)節(jié)站及旁路閥處于關(guān)閉狀態(tài)。Makesurethateveryglandsealsteampressureandtemperatureregulatorstationsandbypassvalvesareintheclosingstate.8.確認啟動汽源溫度必須具有不小于14℃的過熱度。Makesurethatthetemperatureofthestartupsteamsourcecompulsorilyhasadegreeofsuperheatofnotlessthan14℃.9.確認調(diào)節(jié)閥入口的供汽管道中無水。Makesurethatthereisnowaterinthesteamsupplypipelinetotheinletoftheregulatingvalve.汽機培訓教材910.啟每個調(diào)節(jié)閥兩側(cè)的手動截止閥。Openthemanually-operatedvalvesatbothsidesofeachregulatingvalves.11.汽封系統(tǒng)在冷態(tài)啟動狀態(tài)時，輔助汽源向各個汽缸前后汽封供汽，蒸汽通過軸封壓力調(diào)節(jié)閥減壓，再通過減溫器減溫到121～150℃向高低壓前后軸封供汽。如果除氧器能供汽，則切到正常運行系統(tǒng)。Duringacold-statestartupoftheglandsealsystem,theauxiliarysteamsourceshallprovidesteamtotheglandsealsinthefrontandattherearofvariouscylinders.Thesteampressureisreducedbytheglandsealsteampressureregulatingvalveandthesteamtemperatureisdesuperheatedto121℃and150℃byanattemperator.Then,thesteamissuppliedtotheHPandLPfrontandrearglandseals.Ifthedeaeratorhasanabilitytosupplythesteam,thenthenormaloperationsystemshallbeputintoservice.汽機培訓教材912.當汽封供汽母管壓力建立并暖管后，立即啟動汽封抽汽器。Whenthesteampressureinthesteamsupplymainlineoftheglandsealsisestablishedandthesaidmainlineiswarmedup,oneshallimmediatelystartuptheairejectorfortheglandseals.13.確認汽缸的每個汽封腔室均有低度真空。Makesurethateachchamberoftheglandsealsforthecylindershasavacuityatalowdegree.汽機培訓教材914.確認各汽封腔室內(nèi)蒸汽沒有漏入大氣，如果發(fā)現(xiàn)漏汽，則提高汽封抽汽器真空，或調(diào)整壓力調(diào)節(jié)閥或各送汽支路上的送汽截止閥，調(diào)節(jié)各截止閥開度，以降低汽封母管的蒸汽壓力，直至停止向外部漏汽。Makesurethatthesteaminvariousglandsealchambersdoesnotleaktotheatmosphere.Ifanyleakageofsteamisfound,thevacuitymaintainedbyuseoftheairejectorshallbeenhancedorthepressureregulatingvalveorthecut-offvalvesonvariousbranchlinesforsteamsupplyshallbeadjustedortheopeningdegreesofvariouscut-offvalvesshallberegulatedtoreducethesteampressureintheglandsealsteammainlineuntilthesaidleakageofsteamtotheoutsideisstopped.汽機培訓教材915.檢查汽封供汽母管的溫度，檢查高壓缸內(nèi)壁溫度與汽封腔室內(nèi)蒸汽溫度之差值，確保差值小于110℃，確保后汽封送汽腔室內(nèi)蒸汽溫度在121～150℃之間，檢查汽封蒸汽管路疏水是否通暢。Inspectthetemperatureintheglandsealsteamsupplymainline,inspectthetemperaturedifferencebetweentheinnerwalltemperatureoftheHPcylinderandsteamintheglandsealchambers,ensurethesaiddifferencetobelessthan110℃andthesteamtemperatureintherearglandsealsteamsupplychambertobebetween121℃to150℃.Inspecttheglandsealsteampipelinestoseewhetherthedraininsideflowsfreely.汽機培訓教材916.關(guān)閉凝汽器的真空破壞門，啟動抽氣設備，并在凝汽器內(nèi)建立盡可能高的真空，在每個汽封建立起最大流量之前，所需的汽封蒸汽量隨凝汽器真空的改善而增加。Closethevacuumbreakingvalve,startuptheairejectorequipmentandestablishavacuityashighaspossibleinthecondenser.Priortoanestablishmentofamaximumflowrateineachglandseals,thesteamamountnecessaryfortheglandsealswillincreasewithanincreaseofthevacuityinthecondenser.汽機培訓教材917.當負荷逐漸增加時，來自除氧器的蒸汽可以滿足高、低汽封供汽時，則輔助汽源供汽切換到除氧器供汽。這樣高中壓汽封系統(tǒng)與低壓汽封系統(tǒng)相互獨立，整個系統(tǒng)相對穩(wěn)定。WhentheloadgraduallyincreasesandthesteamflowratefromthedeaeratorcanmeetthesteamamountrequiredbytheHPandIPglandsealsystem,thesteamcanbeswitchedoverfromsuppliedbytheauxiliarysteamsourcetosuppliedbythedeaerator.Insuchacase,theHPandIPglandsealsystemareindependentfromtheLPglandsealsystemandthewholesystemisrelativelystable.汽機培訓教材9控制降負荷ControlLoadReduction在控制降負荷時，汽封母管的蒸汽壓力高于0.107MPa(A)，則汽封系統(tǒng)維持正常狀態(tài)，高、低壓汽封供汽由除氧器供給；當汽封母管壓力低于0.107MPa(A)時，即除氧器的汽源不能保證母管壓力時，改由輔助汽源供汽。Whentheloadreductioniscontrolledandthesteampressureintheglandsealsteammainlineishigherthan0.107Mpa(A),theglandsealsystemiskeptinanormaloperationstateandHPandLPglandsealsteamissuppliedbythedeaerator.Whenthesteampressureintheglandsealsteammainlineislowerthan0.107Mpa(A),i.e.thesteamfromthedeaeratorcannotmaintainthepressureinthemainline,thenthesteamshallbesuppliedbyanauxiliarysteamsource.汽機培訓教材9汽輪機停機TurbineShutdown只要存在著保持汽缸內(nèi)真空的必要，就必須向汽輪機各汽封提供密封蒸汽，在凝汽器的抽氣設備停止運行和凝汽器的真空完全消失以前，不得切斷汽封供汽，否則冷空氣流入會使轉(zhuǎn)子表面金屬急劇冷卻，而且還會導致熱的靜止的汽封體變形。Aslongasaneedforkeepingavacuityinthecylindersexists,oneshallsupplysteamtovariousglandsealsoftheturbine.Priortothestoppageoftheairextractionequipmentofthecondenserandafulllossofvacuityinthecondenser,thesteamsuppliedtotheglandsealsshallnotbecutoff,otherwise,coldairenteringintothesteamturbinewouldcauseanabruptcoolingoftherotorsurfacemetalandalsoresultinadeformationofthehotandstillglandcasings.汽機培訓教材9汽輪機停機順序ShutdownSequence

1.在機組盤車和汽封供汽來自外部汽源的情況下，確認凝汽器真空已完全消失。Undertheconditionthatthesteamformaintainingtheturbineturningandtheglandsealsisfromthesteamsourceattheoutside,oneshallmakesurethatthevacuityinthecondenserhasbeenfullylost.2.關(guān)閉汽封冷卻器風機。Closethefanoftheglandsealcooler.3.關(guān)閉各汽封壓力調(diào)節(jié)閥兩側(cè)的手動截止閥。Closevariousmanually-operatedcut-offvalvesatbothsidesoftheglandsealsteampressureregulatingvalve.汽機培訓教材9在切斷汽封冷卻器的風機后，應立即關(guān)閉上述閥門，在汽封體內(nèi)無真空的情況下，汽封供汽的投入導致蒸汽漏入大氣，這些蒸汽會進入潤滑油中，并凝結(jié)成為污染雜質(zhì)，積存在油箱中。Afterthefanoftheglandsealcoolerhasbeenstopped,oneshallimmediatelyclosealltheabove-mentionedvalves.Undertheconditionthatthesealcasingisatzerovacuity,iftheglandsealsaresuppliedwithsteam,thelatterwillbeescapedtotheatmosphereandalsotothebearingbox,mixedwiththelubricationoilandcoagulatedtopollutantsanddepositedintheoiltank.汽機培訓教材9熱態(tài)啟動Hot-stateStartup熱態(tài)啟動狀態(tài)，機組轉(zhuǎn)子溫度接近滿負荷運行工況下的轉(zhuǎn)子溫度，此時所有閥門狀態(tài)同冷態(tài)啟動，只是增加一股熱態(tài)啟動汽源(