1、收稿日期:20021128大型鍋爐爐膛斷面溫度場的試驗研究姚斌1, 婁春1, 劉浩1, 周懷春1, 陳士英2, 邵主建2, 莊群3, 鄭見云3(1. 華中科技大學(xué), 湖北武漢430074; 2. 湖北省電力試驗研究院, 湖北武漢430077;3. 漢川電廠, 湖北漢川432321摘要在大型鍋爐爐膛上采用4個CC D , 實現(xiàn)了爐膛斷面溫度分布的檢測, , 。由火焰圖像重建的爐膛溫度場表明, , 且其偏斜情況與電廠運(yùn)行經(jīng)驗基本一致關(guān)鍵詞; 溫度分布2文獻(xiàn)標(biāo)識碼A文章編號10023364(2003 09002903在典型的四角切圓燃燒鍋爐中, 燃燒工況組織的不合理造成的四角燃燒不均勻、火焰中心偏斜

2、、火焰刷墻等是導(dǎo)致爐膛結(jié)焦、爐管爆破、爐膛滅火等運(yùn)行事故的重要原因。對爐膛斷面溫度分布的準(zhǔn)確掌握可以避免上述事故的發(fā)生。為此, 在爐膛燃燒器以上一斷面布置4個火焰圖像探測器, 通過火焰圖像所攜帶的輻射能水平和爐膛燃燒溫度分布之間的數(shù)學(xué)模型, 將火焰彩色圖像轉(zhuǎn)化為溫度圖像, 得到不同負(fù)荷下爐膛的斷面溫度分布、爐膛斷面火焰中心的位置等燃燒信息, 并對這些信息進(jìn)行分析比較。1漢川電廠1號爐漢川電廠300MW SG 1025/18. 3M314鍋爐是由上海鍋爐廠引進(jìn)美國燃燒工程公司的技術(shù), 經(jīng)優(yōu)化設(shè)計后制造的亞臨界中間再熱強(qiáng)制循環(huán)爐, 單爐膛型布置, 采用四角切圓燃燒方式、鋼球磨煤機(jī)貯倉式熱風(fēng)送粉,

3、設(shè)計煤種為潞安貧煤。爐膛為正方形斷面瘦高型, 寬11. 970m , 深11. 760m , 即其截面熱負(fù)荷高, 容積熱負(fù)荷低, 因而適用于燃用貧煤和無煙煤。燃燒器采用濃淡分離型寬調(diào)節(jié)比煤粉燃燒器, 沿整個燃燒器高度分4層布置。每角燃燒器風(fēng)箱內(nèi)設(shè)有2層起動及低負(fù)荷用油槍。中下部一、二次風(fēng)噴嘴可上下擺動20°, 以調(diào)節(jié)再熱與過熱汽溫。燃燒器上部設(shè)有頂部二次風(fēng)噴口OFA 以實現(xiàn)爐內(nèi)分級燃燒, 減少NO x 排放, 該OFA 可下傾25°。為燃用低揮發(fā)分的貧煤, 該爐采用較高的爐膛斷面熱負(fù)荷、寬調(diào)節(jié)比燃燒器、熱風(fēng)送粉、集中燃燒等措施來強(qiáng)化和穩(wěn)定燃燒, 采用較細(xì)的煤粉及加長燃燒行程

4、來強(qiáng)化燃盡。2試驗準(zhǔn)備2. 1試驗方案試驗系統(tǒng)的網(wǎng)格單元劃分如圖1所示。4個CC D火焰探測器在爐壁四角的看火孔直視布置, 得到的4幅火焰畫面經(jīng)視頻分隔器合成1幅圖像。取4幅火焰圖像中間1層象素對應(yīng)的爐膛斷面為研究對象。斷面空間被分成10×10=100個網(wǎng)格單元, 每個網(wǎng)格單元的大小為1. 197m ×1. 176m 。每個CC D 靶面的中間1層象素劃分為100個單元, 象素單元的編號從CC D1起順時針排列, 象素單元共分為400個。爐膛四角每隔一定距離有看火孔, 爐壁中間有吹灰孔。CC D 布置在靠近爐角的看火孔處, 其中CC D1、CC D3布置在左右墻處, CC

5、D2、CC D4布置在前后墻處, 其距離爐墻均為0. 3m 。2. 2系統(tǒng)建模根據(jù)爐膛尺寸的大小、CC D 布置的位置, 以及鍋爐技術(shù)交流 圖1系統(tǒng)結(jié)構(gòu)的其它參數(shù), 31m , 得平:珔K abs =0. 1420. =0. 103珔K sca =0. 142×1. 8=0. 256根據(jù)輻射成像快速算法計算出新模型中的RE AD 數(shù), 進(jìn)而計算出新模型的系數(shù)UV 數(shù), K 系數(shù)。實驗中只需要重建氣體單元的斷面溫度場, 對于來自壁面部分的輻射采用“扣除”的方式, 即假設(shè)壁面溫度為一個定值。實際的計算公式如下:T 4CCD -V T w =U T g (1 對于上面這個線性方程組的求解,

6、 采用周懷春教授的正則化方法, 計算公式如下:T g =(U T U +D T D -1U T(T CCD -V T w (2 2. 3設(shè)備檢查(1 實驗中的一個重要設(shè)備是CC D 火焰探測器,對CC D 需要做黑體爐標(biāo)定, 標(biāo)定的思想是使修正后的三基色r ,g ,b 之間的相對大小與黑體爐發(fā)出的黑體輻射中三基色代表性波長下的單色輻射能之間的相對大小一致。實驗中所用到的4個CC D 的標(biāo)定系數(shù)見表1。表1CC D 標(biāo)定系數(shù)探頭126探頭227探頭328探頭429C g C b C g C b C g C b C g C b 0. 3080. 057210. 30970. 062480. 324

7、10. 062330. 2920. 05764(2 要根據(jù)鍋爐的尺寸制做好相應(yīng)的視頻線纜以及CC D 電源線纜。(3 由于使用的4個CC D 的光譜響應(yīng)特性不同, 其對于同一物體的真實反映也不盡相同, 因此要對4個CC D 做相對系數(shù)校正, 校正參照物采用實驗現(xiàn)場的鍋爐燃燒火焰。3試驗過程3. 1完成CC D 相對系數(shù)校正以第1個CC D 為基準(zhǔn), 1和2、1和3、1和4號D , 對得, 得到校正系 2所示。圖2修正系數(shù)以及校正系統(tǒng)技術(shù)交流3. 2拍攝斷面溫度場重建的火焰圖像按照預(yù)定方案布置火焰探頭, 在鍋爐標(biāo)高31m 平臺對調(diào)峰試驗過程中11個工況的爐膛燃燒火焰進(jìn)行了斷面溫度場可視化實驗研究

8、。在某時刻以1s 為間隔, 連續(xù)拍攝30幅火焰圖像。在30s 時刻內(nèi), 火焰圖像的變化不大。4試驗結(jié)果及分析表2給出11個工況下重建的斷面平均溫度, 可以看出其與負(fù)荷的變化吻合。320. 67MW 負(fù)荷下重建的斷面平均溫度比152. 45MW 溫度高約250K, 面溫度較高負(fù)荷下降不多, 表2工況負(fù)荷/MW 紅外測溫溫度/K 重建斷面平均溫度/K1預(yù)備效率試驗2002208227T 1630279. 9413611738. 4692變氧量試驗4. 5%2002208227T 1700285. 6513711762. 3363變氧量試驗4. 0%2002208228T 1100297. 9613

9、901787. 2754變氧量試驗5. 0%2002208228T 2045292. 3813861758. 3655倒寶塔配風(fēng)2002208229T 1005287. 0514031779. 0526均等配風(fēng)2002208229T 1600295. 6713641703. 1837縮腰配風(fēng)2002208230T 1033305. 714101750. 3778寶塔配風(fēng)2002208230T 1728320. 6714341779. 029均等配風(fēng)2002209201T 1044154. 6112581570. 99410縮腰配風(fēng)2002209201T 1428154. 6112461548.

10、 06911縮腰配風(fēng)2002209201T 1645152. 4512151513. 225在某時刻以1s 為間隔, 連續(xù)拍攝 30幅火焰圖像。在30s 時刻內(nèi), 重建的溫度場變化不大。由于篇幅的限制, 這里只給出2個典型工況斷面溫度場可視化重建結(jié)果(圖3、圖4 。圖3工況8的斷面溫度場可視化重建結(jié)果圖4工況11m , 高負(fù)荷工況負(fù)200K “中間高, 。當(dāng)負(fù)荷不變時在一段時間內(nèi), 斷面溫度分布變化不大。高負(fù)荷下溫度均保持在1200K 2000K 的范圍內(nèi)。根據(jù)用熱電偶測溫的結(jié)果, 斷面4個角上均為1000(即1300K 左右; 低負(fù)荷下溫度保持在1000K 1800K 的范圍內(nèi)。熱電偶測溫的

11、斷面4個角上均為800(即1100K 左右, 與溫度場重建結(jié)果相差不大。從圖3可以看出, 高負(fù)荷下火焰中心偏向后墻, 對此, 電廠技術(shù)人員反映, 后墻溫度的確偏高, 后墻水冷壁高溫區(qū)段曾發(fā)生過水冷壁爆管事故, 斷面溫度場重建的結(jié)果很好地反映了1號爐的這一運(yùn)行特征。從表2重建的斷面平均溫度可以看到, 在負(fù)荷基本相等的情況下, 倒寶塔配風(fēng)的工況5與均等配風(fēng)的工況6相比較, 前者的斷面平均溫度比后者高出70K 左右, 這與倒寶塔配風(fēng)的工況下火焰中心上升的實際情況是相符合的。5結(jié)論(1 火焰圖像重建的爐膛溫度場結(jié)果表明, 燃燒器區(qū)域之上某一個斷面的溫度場呈現(xiàn)典型的單峰分布特征, 且其偏斜情況與電廠運(yùn)行

12、經(jīng)驗基本一致, 320. 67MW 負(fù)荷下重建的斷面平均溫度比152. 45MW 負(fù)荷下重建的斷面平均溫度高約250K, 與實際情況比較吻合。(2 火焰圖像重建直接給出爐膛的斷面溫度分布、爐膛斷面火焰中心的位置等燃燒信息, 可以顯示火焰中心偏斜、火焰刷墻等異常工況, 對于鍋爐燃燒調(diào)整有著重要的作用。(下轉(zhuǎn)第39頁技術(shù)交流2. 4加強(qiáng)管理、維護(hù)與檢修加強(qiáng)潤滑管理, 要實行定質(zhì)、定量、定點(diǎn)、定期、定人的五定原則。加強(qiáng)維護(hù), 以防止設(shè)備振動過大。對機(jī)械設(shè)備各部位緊固件要經(jīng)常檢查, 及時消除因松動而引起的振動現(xiàn)象。提高檢修質(zhì)量, 防止因檢修質(zhì)量而引起的振動和漏油。3結(jié)語鍋爐輔機(jī)軸承箱漏油是一個常見的問

13、題, 只要找出漏油原因, 采取恰當(dāng)?shù)姆缆┲温┓椒? 定能取得良好的效果。值得注意的是:油脂剪切率, 密封只要設(shè)計得合理, , 。在分析的4種結(jié)構(gòu)中, 組合式迷宮、異形擋油環(huán)+引油環(huán)和靜聯(lián)合密封裝置的設(shè)計、安裝簡便, 不需調(diào)整, 密封效果好, 基本不需維護(hù), 且被長期實踐檢驗證明是行之有效的改進(jìn)方法, 值得推廣。參考文獻(xiàn)1周愛民, 等. 鍋爐輔機(jī)軸承箱改變潤滑方式應(yīng)注意的問題J.電站輔機(jī),2003, (3 .2汪德濤. 潤滑技術(shù)手冊, 第一版,1998.3, 1999. , . J.山東電力技, (1 ., 等. 利用入口負(fù)壓消除送風(fēng)機(jī)軸承座漏油J.石油規(guī)劃設(shè)計, 2000, (11 .(上接第

14、31頁參考文獻(xiàn)1Zhou HC ,Han S D ,Sheng F ,et al. Visualization of three 2dimen 2sional tem perature distributions in a large 2scale furnace via regu 2larized reconstruction from radiative energy images :numerical studies. Journal of Quantitative S pectroscopy and Radiative T rans fer 72. 2002,361383.2薛飛, 李

15、曉東, 倪明江, 等. 基于面陣CC D 的火焰溫度場測量方法研究J.中國電機(jī)工程學(xué)報,1999,19(1 :3941.3盛峰, 周懷春, 韓曙東. 基于針孔成像模型的爐膛輻射成像快速算法J.華中理工大學(xué)學(xué)報,2000,5:9597.4婁春, 韓曙東, 劉浩, 等. 一種煤粉燃燒火焰輻射成像新模型J.工程熱物理學(xué)報,2002,23.5周懷春, 韓曙東, 鄭楚光. 兩種輻射溫度圖像監(jiān)測方法的模擬比較分析及其使用性評價J.中國電機(jī)工程學(xué)報,2002,18(2 :14.6鄭楚光, 柳朝暉. 彌散介質(zhì)的光學(xué)特性及輻射傳熱M.華中理工大學(xué)出版社,1996.(上接第35頁另由于熱風(fēng)溫度降低近100, 使高

16、溫空預(yù)器出口風(fēng)溫能在低于340下長期運(yùn)行, 可有效防止空預(yù)器管壁溫度過高引起的加速氧化過程, 保證空預(yù)器的設(shè)計壽命。5結(jié)論(1 伊犁第二火電廠鍋爐實際運(yùn)行中所出現(xiàn)的排煙溫度和熱風(fēng)溫度高問題, 主要因鍋爐漏風(fēng)大、積灰沾污嚴(yán)重以及各段受熱面熱負(fù)荷分配不合理所致。對此進(jìn)行改造后, 鍋爐排煙溫度比改造前下降3040; 熱風(fēng)溫度比改造前下降約100, 鍋爐蒸汽參數(shù)正常。(2 尾部吹灰器吹灰后排煙溫度降低近10, 熱風(fēng)溫度降低近18; 通過近1年的運(yùn)行檢查發(fā)現(xiàn), 尾部煙道各段受熱面積灰情況大為好轉(zhuǎn), 受熱面表面清潔, 基本無掛積灰現(xiàn)象。(3 通過技術(shù)改造, 1號爐總體鍋爐效率提高1. 9%, 發(fā)電煤耗降低

17、8. 1g/(kW h ;2號爐總體鍋爐效率提高2. 44%, 發(fā)電煤耗降低10. 15g/(kW h 。技術(shù)交流THERMAL POWER GENERATIONV ol. 32N o. 9Sep. 2003Contents &AbstractsEVA L UATION OF ENERG Y AN D POWER ENGINEERING PR OJECTS FR OM THE VIEW POINT OF NATURA L RESOURCES YE H an -dong et al (2I n present -d ays o f giving increasingly prominen

18、ce to environmental protection problems , it is neccess ary to adopt a comprehensive evalu ation method , w hich can take tech nical , e 2conomical and environmental factors into accou nt , for evalu ating energy and pow er engineering projects. The air , w ater , fuel and so on consumed in producti

19、on (including th at h ave been polluted should been convrted into natural resources , the definition o f final evalu ation index , w hich is called the efficiency o f natural being a ratio o f the energy sup 2ply production to the sum o f values concerning consumed natural resources. The principle o

20、 f this comprehensive evalu ation method h as been T aking the combined cycle heat and electricity co -generation system o f a prep aratory natu al -gas firing gas turbine u nit as example , a in comp arison heat and electricity sep arate generation system h as been roughly corried out.OPTIMA L LOAD

21、 DISTRIBUTION IN POWER P LANT BASE D ON A L Yi -ping et al (6The b asic principle o f genetic algorithm h as briefly been described. U nder application o f the s aid plants , o f optim al load distribution among multiple u nits in operation h as been solved. I t can be fou nd from results o f simula

22、ted calculation , features fast speed o f computing operation and being easy to use. The online dynamic optimization o f u nits load can be , o f operation.PRESENT SITUATION AN D LIMITATIONS OF SL URR Y AS SUBSTITUTE FOR OI L -FU 2E L JIA Ming -sheng et al (10A new tech nology o f using coal -w ater

23、 slurry (in year. The features o f CWS , the problems to be faced , and the limitation o f using CWS h ave been analysed , putting forw ard the oil -fuel u nder certain conditions , and the applicabity o f CWS is limited. The wide application and m arket future o f CWS can s aid should be cautiously

24、 developed.COMPARISON AN D PERFOR MANCE TEST METH ODS FOR COMBINE D CYC LE HEAT RECOVER Y BOI LERS AI Wei -guo et al (13Directing against the features o f gas turbine s heat recovery boiler , the design ch aracteristics o f s aid boiler h ave been analysed , summ arizing several methods for measurin

25、g and calculating the utilization coefficient o f heat recovery boiler and the flow rate o f inlet gas. Combined with the field practice , a cou nter b alance method for heat recovery boiler h as been put forw ard , coming to a conclusion o f using di fferent method according to di fferent situ atio

26、n in the field.DISCUSSION ON PR OB LEMS OF CH OOSING WATER -LEVE L EQUI LIBRIU M CONTAINER AN D PRESSURE CORRECTIONG AO Q i -fan (17Structure and perform ance o f several equilibrium containers o f di fferenti al -pressure type w ater level indicater h ave been presented , the influence o f drum pre

27、ssure upon the mea 2surement o f w ater level being analysed. The methods o f pressure correction and recommend ations for type selection o f some equilibrium containers are also given.TEMPERATURE FIE LD AN D THER MA L STRESS FINITE E LEMENT ANA LYSIS OF A 50MW STEAM TURBINE S CYLIN DER IN A POWER P

28、 LANT LI Yi -min et al (21A three dimentional finite element analysis o f the temperature field and the therm al stress field regarding a 50MW steam turbine s high pressure cylinder in a pow r plant u nder di f 2ferent operation conditions h as been carried out. The results show, the position o f ca

29、lculated m ax. stress tallies completely with th at o f the cracked cylinder , providing important tech nical b asis for evalu ating the steam cylinder s s afety and calculating the s aid cylinder s residu al service -li fe.STRENGTH ANA LYSIS OF CRACKE D PART ON CYLIN DER WA LL IN STEAM TURBINE G AO

30、 Yu an -hui et al (25Applying shell theory , the internal pressure stress and the therm al stress o f the cracked p art on cylinder w all in a 51-50-1type steam turbine h ave been analysed and calculated , and the s afety o f cracks being evalu ated. At the s ame time , some recommend ations for the

31、 cylinder defects and the steam turbine operation h ave been suggested. I t is considered from analysis th at the s aid cracks are s afe , th at is to s ay a single -stage brittle fracture can not occur.TEST AN D STU DY ON TEMPERATURE FIE LD OVER CR OSS -SECTION OF LARGE -SCA LE BOI LER YAO Bin et a

32、l (29The flame im age in the furnace o f a largescale boiler h as been detected by using four CC D flame detectors. Through processing o f the flame im age , the detection o f temperature dis 2tribution over the furnace cross -section o f a boiler h as been realized , giving the temperature distribu

33、tion over s aid cross -section u nder various operation conditions , and the results being analysed and comp ared. The results o f furnace temperature field created by the flame im age show th at the temperature field over the cross -section above the zone o f burners appears as a typical single -pe

34、ak distribution ch aracter , and its skew ness is b asically consistent with the operational experience in the s aid pow er plant.CAUSE ANA LYSIS AN D REME DIA L MEASURES FOR SOMEWH AT HIGHER CARBON CONTENT IN F LY ASH OF BOI LERSHE Jing et al (32The causes leading to somew h at higher carbon conten

35、t in fly ash o f boilers h ave been analysed from several aspects , namely fuel , prim ary air , terti ary air , and oxigen rate etc. . Through retro fit o f the fine pulverized coal sep arator and adjustment o f coal sorts , prim ary air velocity and air temperature , as w ell as burning admixture

36、o f other fuel , the carbon content in fly ash during the time o f burning single coal h as been decreased from an original value o f 8%to about 2. 4%,and during the time o f burning simutanuously admixture o f blast -furnace gas , the carbon content in fly ash can be controlled to below 8%,enh anci

37、ng the boiler efficiency from 89. 4%in 1998to 92. 4%in 2002.RETR OFIT OF TWO 130t/h PU L VERIZE D COA L BOI LERS IN YI LI THER MA L POWER P LANT N O. 2DUE TO HIGH EXH AUST G AS TEMPERATURE THEREOF ZHI H uo -ting et al (34I n view o f troublesome problems o f high exh aust gas temperature and high ho

38、t air temperature h aving existed after putting tw o CG -130/3. 82-M 12type boilers into operation at Yili Therm al Pow er Plant N O. 2, corresponding retro fitting schemes h ave been studied and w orked out , namely renewing 107m 2area o f superheater in the boiler , increasing heating surface area

39、 o f a p arty o f the economizer , adding 8steam soot -blow ers in the heat recovery gas duct. The operation after retro fitting show s , the exh aust gas temperature h aving been low ered by 30, the hot air temperature by 100, obtaining good results o f operation.CAUSE ANA LYSIS OF OI L LEAK AGE FR OM BEARING BOXES OF BOI LER AUXI LIARIES AN D REME DIA L METH OD THEREOF ZH OU A