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454159)[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]T K263.6 [文献标识码]B [文章编号]10023364(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。

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N30016.7(170)/537/537Ó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3.8M Pa,3号为4.6M Pa 。

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2.6M Pa 。

(2)东汽型机组2号瓦中心高差设计时预留(0.30~0.36)m m,预留中心高差时已考虑运行中的负荷分配情况。

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。

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N200130/535/535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30L m 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,顶技术交流q w 热力发电#2003(3)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0.50m m。

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。

3125MW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N125135/535/535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30L m 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结论根据上述3种情况,认为在检修中应注意以下几点:(1)300M W(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)200M W(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125M W(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。

(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豪顿华空预器空气侧烟气侧甲侧值/Pa7141236乙侧值/Pa5811076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。

技术交流热力发电#2003(3)q xth e smok e emission bein g below the stan dard limi t sp ecified b y th e state.PRACTICE OF CORRECTING WATER WALL AND FURNAC E BODY SKEWNESS FOR BOILER NO.3IN DAGANG POWER,,,,,,,,,,,,,,,,,,,,,,,,,,,,,PLA NT,TIANJIN MUNICIPALITY ZHA NG Shu-ming(41) D eformation of th e fu rnace b ody had oc cur red on boiler N O.3in tittle power p lant,h ence,measu remen t and cause analysis of said deformation h ave been carried out,it is c on-sid ered th at th e b asic reason of th e fu rnace bod y deformation is d ue to n on un iform settle men t of b oil er.s stee l frame fou n dation.Th en,effective ad justmen t of the said foun dation was mad e du rin g the cou rse of r eplacin g the sai d water wall.OPERATION PERFORMANCE ANA LYSIS A ND MEASURES TAKEN FOR IMPROVING SOOT BLOWERS ON BOILERS NO.5AND,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,6AT JINGYUAN POWER PLA NT WANG Gang(44) In appl ication of soot blow ers on b oi lers NO.5an d6at Jin gyu an Power Plant,ph enomen a of blowin g d amage on w ater walls and tu be-bu rsti ng on the economizers h ave oc-cur red many times.Thr ou gh analysis,it is conside red th at the IR-3D typ e soot blowe rs can b e completely stopp ed un der c on dition w ithout slaggin g occ urr ed in th e fu rnace.At th e same time,in or der to corr ectly u se the lon g-stem soot bl ow ers,an op timal b lowing cycle sh ould be for mu lated,an d oper ational mai ntenan ce an d management of th e soot blower s must b e stren gth ene d.TEST AND RESEARC H ON MEASURING PARTICLES.FLOW VELOCITY IN TWO-PHASE FLOW BY USING OPTIC AL SIGNAL,,,,,,,,,,,,,,,,,,,,,,,,,,,,C ROSS-C ORRELATION METHOD YUAN Zhen-f u et al(47) Th e signal flu ctuation of optical transmissi on inten sity may b e occu rred wh en particles in the gas-solid two-ph ase flow are p assing throu gh the l ight-beam of lasers,the part-i cles.flow velocity can be obtain ed via c ross-correlation calcul ation after samp ling tw o sign als of optical flu ctuation from pr ob es allocate d at up-stre am an d dow n-stream. Test show s that the anti-in terfe renc e ab ility of the said measu ring te chn iqu e is stron g,th e accu racy of me asur ement can meet the requ ire men ts in en gineer ing measure men t. He nce,it is suitab le for me asur ing th e velocity of non-sp heric al and non-transparen t p ar tic les.PRESENT SITUATION OF BED-TEMPERATURE C ONTROLLING FOR C FB BOILERS AND IMPROVING MEASURES THEREOF ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,WU Shu-zhi et al(51) A n investigation and stu dy on th e p resent situ ation of bed-temperatu re controlling for CF B b oilers h ave been performed.It is p ointed ou t th at the existi ng controlling mode h as too small ad justab le amp litud e,can.t e ffectively r egulating the b ed-temp eratu re of C FB b oil ers.Th rough stu dy an d analysis,a recommend ation of estab lish ing a tw o-inp ut an d two-outpu t mu lti-var iable controllin g system has been pu t forw ard,then,w hile th e de viation of be d-tempe ratu re is comparatively small,on ly th e match ratio of pr imary an d se cond ar y air is adju sted;wh ile the said d eviation is comparative ly large,th e coal-feed ing amou nt an d air qu antity can simultaneou sly be ad ju ste d.,,,,APPLICATION OF FOUR CORNER OPPOSED TANGENTIAL FIRING ON UTILITY BOILERS HE Zhi-qiang et al(53) F ou r corner op posed firin g,as a n ew arrange men t p atter n for tangen ti al firing,has b een su ccessfully used on boiler s with variou s cap ac ity level an d d ifferen t coal sorts.Pratice shows,the sai d fir ing patte rn has ob viou s effec tiven ess for solvin g pr oblems often oc cur red in b oi lers,su ch as d eviation of fl ue gas tempe ratu re,slaggin g in the fu rnace,h igh temp eratu re corrosion,as w ell as i n aspe ct of re du cing NOx emission.,,,,,,,,,,OPTIMIZTION OF RETROFITTNG SC HEME FOR THE COMBUSTIN SYSTEM X IU Xing-jing et al(57) A systematic an al ysis and e valu ation of slagging prob lems occu rred on b oilers in Yu nfu Pow er Plant,Gu angd on g Provin ce,h as been carried ou t.Based on the prin ciple of em-phatically solvin g the slaggin g p roble ms and si mu ltan eously taking acc ou nt of stab ilizing c omb ustion,an optimal retrofi ttin g sch eme is su ggested,i nclu din g the blu nt b od y of bu rners to be set up right,th e mi dd le-and lower-l evel sec on dary air to be con cen tr atically configu red,the b u rnin g c avity with blu nt b od y to b e u sed for the lower-le ve l prima-ry air,as w ell as mak ing th e left and r ight side of p ulver ized c oal and air mixtur e flow to be ri ch and lean respec tive ly etc.,It is expected that th e desired results of retrofitting c an be achie ve d..APPLICATION OF FUEL GAS EXC ITING WAVE OPERATED SHOOT BLOWERS ON A IR PREHEATER OF A670t/h BOILER ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Li Wen-yuan et al(60) A nalysis of ash clogging ph enomen on on air preh eater of Datong Power Plant No.2u nd er the S tate Powe r Corp has b een c ar ried ou t.It is c on sid ere d that th e efficien cy of orig-i nally d esigned steam ope rate d shoot b lowers was influen ced up on b y several fac tors,suc h as n on-su itable p osition of in stalling,incr easing h umid ity of steam at the final en d,as well as non-re asonabe design of nozzle an d stroke c on cern ing the steam op erated sh oot b low ers etc.F or th ese reasons,it is tried to install fue l gas impu lse e xc itin g wave ope rate d shoot b lower s for rep lacing some steam op erate d sh oot blow ers.Afte r p utting the ne w typ e shoot blowe rs into op eration,the resistan ce on both air an d gas sid es of the air pr e-heater has b een ob viou sl y lower ed,th e effectivene ss of shoot b lowin g b eing excellen t.C AUSE ANALYSIS OF OVER-TEMPERATURE OC CURRED ON STEAM TURBINE'S BEARING SHOE AND IT'S TREATMENT,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,LI Shou-lun et al(62) S ever al typical ph enomina of beari ng shoe's over-temper atu re tr ou b le have bee n an alyz ed.Throu gh appr op riate tre atmen t,all ow ing the temper atu re of said bearin g shoe to r e-tu rn to n ormal.BENDING ROTOR'S VIBRATION CONTROL OF STEAM TURBINE FOR A300MW UNIT YUAN Li-ping et al(64),,,,,,In view of the h igh-pre ssure rotor's ben din g fault occu rred on steam tur bin e of a home-made300MW un it,the rotor's vib rati on r esp on se an d the u nb alan ced c ompon ent have been c al culated an d analyzed.S ome measu res,su ch as single rotor h igh-speed dynamic eq uilib ru m,correction and inclin able be ar ing shoe's ap plication,have be en tak en,en-ab lin g the vib rati on amplitu de to red uce to a region u p to stan dard.APPLICATION OF ELECTRO-HYDRAULIC GOVERNING SYSTEM WITH INTEGRATED AC TUATOR ON UNIT NO.3AT BEIP-,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,IAO POWER PLANT MA Ren-ku et al(66) A stu d y on ap plication of i ntegrated actu ator in electro-h ydrau lic governin g syste m w hich is a govern ing system withou t control-oil sou rce of steam tu rb ines has be en p rese nted. Th e su ccessful app licati on of th e said c on trol mod e,in whic h the stagger oil valve is d irectly dr iven b y the said actu ator,at Beipi ao The rmal Powe r Plan t r esolved comp letely the p roble m of infu encin g th e electro-hyd raulic d evice d ue to flu id med iu m pollu tion,an d enh ance d su ccessfu lly the r eliability of un it.s op eration,at th e same time,provid ed ne w way an d means for retrofitting ele ctro-hydr au lic govern ing system of med ium and small u nits,havin g positive effe ct to d evelopin g steam turb ine gover nin g system wi th ou t control -oil sou rce and withou t fluid workin g me diu m.DEVELOPMENT OF A DATA AC QUISITION AND WARNING SYSTEM GOVERNING META LLIC WALL TEMPERATURE IN ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,BOILERS ZHU Zhi-gang et al(69) Tak ing th e data ac qisi tion an d warnin g syste m govern ing metallic wall temp eratu re in b oi lers at Hu an engNan ton g Power Plan t as examp le,th e realization of data ac qu isition,su-pervision,off-limit warn ing,an d statisti c man age me nt syste m govern ing metallic wall temp erature in b oi lers by usin g i ntelligen tly ad van ced techn ology and ne tw ork commun ica-tion tech nology h as bee n presen te d.Th e said system h as good u nive rsality,having b right fu tu re for p op ulari zation.UPDATING AND RETROF ITTING THE EXC ITATION REGULATING DEVICE OF A60MW GENERATOR LI Jian(72),,,,,,Th e statu s of retrofittin g e xcitation syste m for a60MW gener ator in Magan g Th ermal Powe r Pl an t h as been presented.It fe atu res th e or igi nal main c ircu it of excitation hasn.t been c hanged,i.e.the fun damental performan ce and p roper ty of origin al system are still r ese rved,only the re gu lating d evice is up dated an d r etr ofitted,and better ec on omic as-pect obtaine d.Th e r egulating d evice used for retrofitting is a32-bit nu meric signal processor,th e regu lation spee d,c ap ability for coun ter-inter fere nce,and re liability of the e xci tation syste m havin g b een en hanc ed b y u sin g D SP techn ology.òOriginated from:1972òAuthorized by:China State Power CorpòSponsored by:Thermal Power Research Institute under C hina State Power C orpChinese Society for Electrical EngineeringòEdited and Published by:Magazine Agency of Thermal Power GenerationòDistributed by:Distribution Bureau of News-papers And Periodicals under Shaanxi Provincial Office of Postal Service。