汽轮机轴瓦温度高的原因分析及处理

汽轮机轴瓦温度高的原因分析及处理

李守伦,张清宇

(焦作电厂,河南焦作 4159)

[摘 要] 对几种典型轴瓦温度高的现象进行分析,并通过适当处理,清除了故障,使轴瓦温度恢复正常。[关键词] 汽轮机;轴瓦;轴瓦温度

[中图分类号]TK263.6 [文献标识码]B [文章编号]100233(2003)03006202

汽轮机轴瓦温度是机组运行控制的重要参数之一。轴瓦温度高会严重威胁机组的安全运行,本文对几种典型轴瓦温度高的现象进行了分析,并介绍对其的处理方法及结果。

荷分配情况。现场观察轴瓦钨金带有磨损痕迹而非烧毁痕迹,判断钨金为运行中磨损。由于停机时1100r/min为顶轴油泵开启转速,而顶轴油孔被堵死,导致无法形成轴瓦油膜,造成大轴与轴瓦直接磨擦,引起瓦温迅速升高。根据机组运行中2号瓦油膜压力逐渐增高的趋势,判断2号瓦标高随机组运行渐入稳态而逐渐升高,由于预留中心高差不足,导致运行中磨损。

(3)由于3号瓦未磨损,2号瓦被磨损约0.20mm,故仅修刮2号瓦下瓦被磨损的钨金;开出顶轴油囊,疏通顶轴油孔;2号瓦结合面镗去0.20mm后将轴瓦恢复,预留中心高差增大0.20mm,最终达到(0.50~0.56)mm。

(4)处理后,机组运行情况良好,2号瓦温度一直在标准范围内,其间因锅炉原因再次停机时瓦温亦无变化。

1 300MW汽轮机2号轴瓦(东方汽轮

机厂)

(1)河南省某厂2号机为东方汽轮机厂(东汽)生产的N300

16.7(170)/537/537

Ó型(合缸)汽轮

机。机组大修后运行情况良好,在做甩负荷试验时,当转速降至1100r/min时,2号轴瓦瓦温突然升高,由68e急剧升至92e,且随转速降低有升高趋势,后被迫停机。

该机2号轴瓦系带球面套的椭圆轴承,自动调整,双侧进油,为强迫液体润滑轴承。

停机后解体检查,发现该轴承下侧钨金磨损严重,顶轴油孔被钨金全部填塞,油囊已磨平,两侧油孔亦有钨金堆积现象,轴承顶隙增大0.20mm,其它检修尺寸无异常变化。查大修及运行记录,大修时中心调整在制造厂的标准内。启动时油膜压力:1号为4.2MPa,2号为3.8MPa,3号为4.6MPa。冲转后油膜压力:1号为2.6MPa,2号为2.1MPa,3号为2.7MPa。油膜压力均与中心调整值相吻合,无异常现象。但是,根据现场记录,随运行时间的增加,2号瓦的油膜压力随缸温的增加而逐渐增高,最高达到2.6MPa。

(2)东汽型机组2号瓦中心高差设计时预留(0.30~0.36)mm,预留中心高差时已考虑运行中的负

2 200MW汽轮机2号轴瓦(东方汽轮

机厂)

(1)河南省某电厂6号机为东方汽轮机厂生产的N200

130/535/535型汽轮机。在2000年9月的大

修中进行了通流部分改造。因为更换新转子,致使2号轴瓦处间隙过大,便更换了2号轴承。该轴承为推力支持联合轴承,支持部分为三油楔形式,瓦枕和瓦为球面定位方式。大修后开机过程中,瓦温随转速升高而逐渐升高,当瓦温达到94e时,被迫打闸停机,其间油膜压力无变化,振动亦保持在30Lm以下。停机后翻瓦检查,发现此瓦支持部分上瓦钨金磨损,下瓦无磨损痕迹,其余部分无异常。瓦各紧力、扬度无变化,顶

wq 热力发电#2003(3)

技术交流

隙大了0.10mm。

(2)因仅上瓦磨损,其余无异常,且油膜压力正常无变化,初步判断瓦顶隙偏小。查大修记录,顶隙为0.40mm,复核现场瓦顶隙为0.50mm。大修记录符合制造厂(0.40~0.50)mm要求。以前也多次更换2号轴瓦,从未发生此类问题。总结前几次结果,发现更换轴瓦时间隙均接近上限,而此次偏下限,所以此次轴瓦时间隙均接近上限,而此次偏下限,所以此次轴瓦发热的直接原因是顶隙偏小,导致轴承上瓦和大轴摩擦发热。(3)因轴瓦顶隙已经为0.50mm,接近上限,所以仅将下瓦钨金修刮研平,然后将轴瓦恢复。

(4)经处理,在开机及以后的运行中,2号轴瓦温度一直在规定的范围内。

根据上述3种情况,认为在检修中应注意以下几点:(1)300MW(东汽型)汽轮机2号轴瓦因受汽缸热膨胀影响较大,可按制造厂标准适当降低2号轴承标高,从而避免轴承标高因膨胀而升高,导致轴瓦磨损引起瓦温升高。

(2)200MW(东汽型)汽轮机2号推力支持轴承在更换新瓦时,顶隙应按0.15%D(轴承直径)执行,靠近上限标准。尽量避免使用制造厂提供的下限标准。(3)对于125MW(上汽型)汽轮机(或大容量汽轮机)的球面轴瓦,球面紧力应按制造厂提供的下限标准使用,且应尽量向间隙方向靠近,从而提高轴瓦的自定位能力,避免因紧力过大,造成轴瓦失去自定位能力而导致的偏磨。

(4)各球面轴瓦在运行后翻瓦检查时,应尽量避免球面的损伤。回装时应特别注意轴瓦的回装到位和球面的活动情况,杜绝轴瓦翻不到位而强制敲打到位的行为。

及揭瓦后的轴瓦偏磨情况,初步判断为瓦球紧力过大,回装时轴瓦偏斜,运行时导致轴瓦不能自定位,从而引起轴瓦偏磨,使瓦温升高。另外单侧泄油,使油膜压力不能建立,导致油膜压力很低,几乎为0。

(3)上汽125MW汽轮机3号轴瓦要求球面壳体与球枕间隙为(0~0.02)mm。复核3号轴瓦实际紧力为0.01mm,抽取0.03mm垫片后将轴瓦恢复。

(4)处理后,机组开机情况良好,运行时瓦温也在规定的范围内。

4 结 论

3 125MW汽轮机3号轴瓦(上海汽轮

机厂)

(1)河南省某电厂2号机为上海汽轮机厂(上汽)生产的N125

135/535/535型汽轮机,于2000年10

月进行大修。该机3号轴瓦为椭圆型,由瓦衬、球面壳体及球枕组成。在大修后开机过程中,瓦温逐渐升高,当转速升至3000r/min时,瓦温达92e,且有继续升高之势,被迫停机检修。在瓦温升高过程中,油膜压力反而很低,几乎为0;各瓦振动情况良好,均在30Lm以下。翻出轴瓦检查,发现轴瓦钨金和大轴均成偏磨状态。在前侧大轴和轴瓦均有2/3瓦长磨痕,而另外1/3均不接触。轴瓦前侧阻油边磨痕较深而后侧阻油边无磨痕。复核3号轴瓦紧力为0.01mm,其余各项均满足要求。

(2)根据升速过程中油膜压力很低,几乎为0以

(上接第61页)

第二发电厂1号炉甲侧空预器仍采用蒸汽吹灰,而乙侧空预器采用激波吹灰。自2002年安装投运至今,已连续运行200余天,二者均运行正常,能实现集控室远方操作和自动联锁保护。2003年1月对二者进行了比较试验,结果见表2。

表2 蒸汽吹灰与激波吹灰阻力比较

项目甲侧值/Pa乙侧值/Pa

豪顿华空预器

空气侧714581

烟气侧12361076

从表2可以看出,使用激波吹灰后,吹灰效果比蒸汽吹灰有一定的好转,空气侧及烟气侧阻力分别降低133Pa、160Pa。

4 结 论

激波吹灰器是一种新型的吹灰设备,其利用冲击、震动使积灰脱落,可使空预器换热元件长期保持清洁状态,保证良好的换热效率。燃气脉冲激波吹灰避免了蒸汽吹灰远行程过热度下降和蒸汽带水的问题,正确使用情况下不会对传热元件造成损坏。

热力发电#2003(3)

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thesmokeemissionbeingbelowthestandardlimitspecifiedbythestate.

PRACTICEOFCORRECTINGWATERWALLANDFURNACEBODYSKEWNESSFORBOILERNO.3INDAGANGPOWERPLANT,TIANJINMUNICIPALITY,,,,,,,,,,,,,,,,,,,,,,,,,,,,,ZHANGShu-ming(41)

DeformationofthefurnacebodyhadoccurredonboilerNO.3intittlepowerplant,hence,measurementandcauseanalysisofsaiddeformationhavebeencarriedout,itiscon-sideredthatthebasicreasonofthefurnacebodydeformationisduetononuniformsettlementofboiler.ssteelframefoundation.Then,effectiveadjustmentofthesaidfoundationwasmadeduringthecourseofreplacingthesaidwaterwall.

OPERATIONPERFORMANCEANALYSISANDMEASURESTAKENFORIMPROVINGSOOTBLOWERSONBOILERSNO.5AND6ATJINGYUANPOWERPLANT,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,WANGGang(44)

InapplicationofsootblowersonboilersNO.5and6atJingyuanPowerPlant,phenomenaofblowingdamageonwaterwallsandtube-burstingontheeconomizershaveoc-curredmanytimes.Throughanalysis,itisconsideredthattheIR-3Dtypesootblowerscanbecompletelystoppedunderconditionwithoutslaggingoccurredinthefurnace.Atthesametime,inordertocorrectlyusethelong-stemsootblowers,anoptimalblowingcycleshouldbeformulated,andoperationalmaintenanceandmanagementofthesootblowersmustbestrengthened.

TESTANDRESEARCHONMEASURINGPARTICLES.FLOWVELOCITYINTWO-PHASEFLOWBYUSINGOPTICALSIGNALCROSS-CORRELATIONMETHOD,,,,,,,,,,,,,,,,,,,,,,,,,,,,YUANZhen-fuetal(47)

Thesignalfluctuationofopticaltransmissionintensitymaybeoccurredwhenparticlesinthegas-solidtwo-phaseflowarepassingthroughthelight-beamoflasers,thepart-i

cles.flowvelocitycanbeobtainedviacross-correlationcalculationaftersamplingtwosignalsofopticalfluctuationfromprobesallocatedatup-streamanddown-stream.Testshowsthattheanti-interferenceabilityofthesaidmeasuringtechniqueisstrong,theaccuracyofmeasurementcanmeettherequirementsinengineeringmeasurement.Hence,itissuitableformeasuringthevelocityofnon-sphericalandnon-transparentparticles.

PRESENTSITUATIONOFBED-TEMPERATURECONTROLLINGFORCFBBOILERSANDIMPROVINGMEASURESTHEREOF,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,WUShu-zhietal(51)

Aninvestigationandstudyonthepresentsituationofbed-temperaturecontrollingforCFBboilershavebeenperformed.Itispointedoutthattheexistingcontrollingmodehastoosmalladjustableamplitude,can.teffectivelyregulatingthebed-temperatureofCFBboilers.Throughstudyandanalysis,arecommendationofestablishingatwo-inputandtwo-outputmulti-variablecontrollingsystemhasbeenputforward,then,whilethedeviationofbed-temperatureiscomparativelysmall,onlythematchratioofprimaryandsecondaryairisadjusted;whilethesaiddeviationiscomparativelylarge,thecoal-feedingamountandairquantitycansimultaneouslybeadjusted.

APPLICATIONOFFOURCORNEROPPOSEDTANGENTIALFIRINGONUTILITYBOILERS,,,,HEZhi-qiangetal(53)

Fourcorneropposedfiring,asanewarrangementpatternfortangentialfiring,hasbeensuccessfullyusedonboilerswithvariouscapacitylevelanddifferentcoalsorts.Praticeshows,thesaidfiringpatternhasobviouseffectivenessforsolvingproblemsoftenoccurredinboilers,suchasdeviationoffluegastemperature,slagginginthefurnace,hightemperaturecorrosion,aswellasinaspectofreducingNOxemission.

OPTIMIZTIONOFRETROFITTNGSCHEMEFORTHECOMBUSTINSYSTEM,,,,,,,,,,XIUXing-jingetal(57)

AsystematicanalysisandevaluationofslaggingproblemsoccurredonboilersinYunfuPowerPlant,GuangdongProvince,hasbeencarriedout.Basedontheprincipleofem-phaticallysolvingtheslaggingproblemsandsimultaneouslytakingaccountofstabilizingcombustion,anoptimalretrofittingschemeissuggested,includingthebluntbodyofburnerstobesetupright,themiddle-andlower-levelsecondaryairtobeconcentraticallyconfigured,theburningcavitywithbluntbodytobeusedforthelower-levelprima-ryair,aswellasmakingtheleftandrightsideofpulverizedcoalandairmixtureflowtoberichandleanrespectivelyetc.,Itisexpectedthatthedesiredresultsofretrofittingcanbeachieved..

APPLICATIONOFFUELGASEXCITINGWAVEOPERATEDSHOOTBLOWERSONAIRPREHEATEROFA670t/hBOILER

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,LiWen-yuanetal(60)

AnalysisofashcloggingphenomenononairpreheaterofDatongPowerPlantNo.2undertheStatePowerCorphasbeencarriedout.Itisconsideredthattheefficiencyoforig-i

nallydesignedsteamoperatedshootblowerswasinfluenceduponbyseveralfactors,suchasnon-suitablepositionofinstalling,increasinghumidityofsteamatthefinalend,aswellasnon-reasonabedesignofnozzleandstrokeconcerningthesteamoperatedshootblowersetc.Forthesereasons,itistriedtoinstallfuelgasimpulseexcitingwaveoperatedshootblowersforreplacingsomesteamoperatedshootblowers.Afterputtingthenewtypeshootblowersintooperation,theresistanceonbothairandgassidesoftheairpre-heaterhasbeenobviouslylowered,theeffectivenessofshootblowingbeingexcellent.

CAUSEANALYSISOFOVER-TEMPERATUREOCCURREDONSTEAMTURBINE'SBEARINGSHOEANDIT'STREATMENT

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,LIShou-lunetal(62)

Severaltypicalphenominaofbearingshoe'sover-temperaturetroublehavebeenanalyzed.Throughappropriatetreatment,allowingthetemperatureofsaidbearingshoetore-turntonormal.

BENDINGROTOR'SVIBRATIONCONTROLOFSTEAMTURBINEFORA300MWUNIT,,,,,,YUANLi-pingetal()

Inviewofthehigh-pressurerotor'sbendingfaultoccurredonsteamturbineofahome-made300MWunit,therotor'svibrationresponseandtheunbalancedcomponenthavebeencalculatedandanalyzed.Somemeasures,suchassinglerotorhigh-speeddynamicequilibrum,correctionandinclinablebearingshoe'sapplication,havebeentaken,en-ablingthevibrationamplitudetoreducetoaregionuptostandard.

APPLICATIONOFELECTRO-HYDRAULICGOVERNINGSYSTEMWITHINTEGRATEDACTUATORONUNITNO.3ATBEIP-IAOPOWERPLANT,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,MARen-kuetal(66)

Astudyonapplicationofintegratedactuatorinelectro-hydraulicgoverningsystemwhichisagoverningsystemwithoutcontrol-oilsourceofsteamturbineshasbeenpresented.Thesuccessfulapplicationofthesaidcontrolmode,inwhichthestaggeroilvalveisdirectlydrivenbythesaidactuator,atBeipiaoThermalPowerPlantresolvedcompletelytheproblemofinfuencingtheelectro-hydraulicdeviceduetofluidmediumpollution,andenhancedsuccessfullythereliabilityofunit.soperation,atthesametime,providednewwayandmeansforretrofittingelectro-hydraulicgoverningsystemofmediumandsmallunits,havingpositiveeffecttodevelopingsteamturbinegoverningsystemwithoutcontrol-oilsourceandwithoutfluidworkingmedium.

DEVELOPMENTOFADATAACQUISITIONANDWARNINGSYSTEMGOVERNINGMETALLICWALLTEMPERATUREINBOILERS,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,ZHUZhi-gangetal(69)

TakingthedataacqisitionandwarningsystemgoverningmetallicwalltemperatureinboilersatHuanengNantongPowerPlantasexample,therealizationofdataacquisition,su-pervision,off-limitwarning,andstatisticmanagementsystemgoverningmetallicwalltemperatureinboilersbyusingintelligentlyadvancedtechnologyandnetworkcommunica-tiontechnologyhasbeenpresented.Thesaidsystemhasgooduniversality,havingbrightfutureforpopularization.

UPDATINGANDRETROFITTINGTHEEXCITATIONREGULATINGDEVICEOFA60MWGENERATOR,,,,,,LIJian(72)Thestatusofretrofittingexcitationsystemfora60MWgeneratorinMagangThermalPowerPlanthasbeenpresented.Itfeaturestheoriginalmaincircuitofexcitationhasn.tbeenchanged,i.e.thefundamentalperformanceandpropertyoforiginalsystemarestillreserved,onlytheregulatingdeviceisupdatedandretrofitted,andbettereconomicas-pectobtained.Theregulatingdeviceusedforretrofittingisa32-bitnumericsignalprocessor,theregulationspeed,capabilityforcounter-interference,andreliabilityoftheexcitationsystemhavingbeenenhancedbyusingDSPtechnology.

òOriginatedfrom:1972

òAuthorizedby:ChinaStatePowerCorp

òSponsoredby:ThermalPowerResearchInstituteunderChinaStatePowerCorp

ChineseSocietyforElectricalEngineering

òEditedandPublishedby:MagazineAgencyofThermalPowerGenerationòDistributedby:DistributionBureauofNews-papersAndPeriodicalsunderShaanxiProvincialOfficeof

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