汽輪機(jī)組熱耗率分析及實(shí)時(shí)計(jì)算

1、收稿日期:20021021作者簡(jiǎn)介:盛德仁(1960,男,浙江大學(xué)電廠(chǎng)熱能動(dòng)力及自動(dòng)化研究所,副教授,從事發(fā)電廠(chǎng)在線(xiàn)性能監(jiān)測(cè)、機(jī)組優(yōu)化運(yùn)行等方面的教學(xué)與研究工作。汽輪機(jī)組熱耗率分析及實(shí)時(shí)計(jì)算盛德仁,李蔚,陳堅(jiān)紅,任浩仁(浙江大學(xué),浙江杭州310027摘要?dú)w納分析了影響汽輪機(jī)組熱耗率的因素,比較性能實(shí)時(shí)計(jì)算與熱力性能試驗(yàn)的異同點(diǎn),重點(diǎn)對(duì)影響熱耗率實(shí)時(shí)計(jì)算準(zhǔn)確性的主要因素及主要參數(shù)進(jìn)行了分析,為發(fā)電廠(chǎng)實(shí)施發(fā)電成本實(shí)時(shí)核算體系,提供理論分析基礎(chǔ)。關(guān)鍵詞熱力性能;熱耗率;實(shí)時(shí)計(jì)算;汽輪機(jī)性能試驗(yàn)中圖分類(lèi)號(hào)TK 262文獻(xiàn)標(biāo)識(shí)碼A 文章編號(hào)10023364(200305001603能源工業(yè)是國(guó)民經(jīng)濟(jì)的基

2、礎(chǔ)產(chǎn)業(yè),是實(shí)現(xiàn)現(xiàn)代化的物質(zhì)基礎(chǔ)。汽輪發(fā)電機(jī)組是實(shí)現(xiàn)電能轉(zhuǎn)換技術(shù)的重要設(shè)備,又是消耗一次能源的大戶(hù)。我國(guó)火力發(fā)電廠(chǎng)平均供電煤耗率為408g/(kW h ,比世界發(fā)達(dá)國(guó)家同類(lèi)指標(biāo)高出50g/(kW h 以上,這表明我國(guó)火電機(jī)組的節(jié)能潛力巨大。汽輪機(jī)組的熱耗率是衡量火電機(jī)組設(shè)計(jì)、制造、安裝、調(diào)試、運(yùn)行管理等環(huán)節(jié)的綜合技術(shù)指標(biāo)。降低機(jī)組的熱耗率在建立發(fā)電廠(chǎng)安全、經(jīng)濟(jì)、穩(wěn)定、可靠的運(yùn)行系統(tǒng)以及在電力市場(chǎng)化,競(jìng)價(jià)上網(wǎng)的成本核算體系中有重要的指導(dǎo)作用。1額定工況熱耗率的影響因素汽輪機(jī)組額定工況熱耗率定義:q =D 0(h 0-h fw +D rh h rh -D rc h rcP el(1式中:D 0為主蒸

3、汽流量;h 0為主蒸汽焓值;h fw 為鍋爐給水焓值;D rh 為再熱蒸汽管道熱段流量;h rh 為再熱蒸汽熱端焓值;D rc 為再熱蒸汽管道冷段流量;h rc 為再熱蒸汽冷端焓值;P el 為發(fā)電機(jī)輸出功率。影響額定工況熱耗率的因素很多,歸納為以下幾點(diǎn):(1發(fā)電廠(chǎng)主要設(shè)備的內(nèi)在性能,諸如汽輪機(jī)、鍋爐等設(shè)備狀態(tài)是否完好,是否采用高新技術(shù)(大容量機(jī)組、超臨界技術(shù)、通流部分全三維設(shè)計(jì)和高效葉型、高效燃燒等。(2機(jī)組運(yùn)行方式。如某些設(shè)備因局部故障而采用高壓加熱器(高加切除運(yùn)行、過(guò)熱器減溫水噴水(從給水泵出口投入、再熱器減溫水噴水等。(3機(jī)組運(yùn)行參數(shù)。運(yùn)行參數(shù)可以分為可控與不可控2類(lèi)?？煽貐?shù)(如主蒸

4、汽溫度、壓力、真空等是否在該工況最優(yōu)運(yùn)行參數(shù)下運(yùn)行等。(4一些旁通閥、疏水閥是否存在嚴(yán)重泄漏等。2機(jī)組性能試驗(yàn)與性能實(shí)時(shí)計(jì)算汽輪機(jī)組的熱耗率是通過(guò)熱力性能試驗(yàn)后計(jì)算得到的。熱力性能試驗(yàn)的目的是要知道汽輪機(jī)組實(shí)際運(yùn)行性能,如對(duì)剛投產(chǎn)的新機(jī)組,要做性能考核試驗(yàn),來(lái)檢驗(yàn)機(jī)組是否達(dá)到制造廠(chǎng)家在技術(shù)合同上保證的熱耗率;對(duì)機(jī)組大修前、后也要進(jìn)行常規(guī)熱力性能試驗(yàn),來(lái)檢驗(yàn)大修的質(zhì)量。此時(shí)需要消除運(yùn)行方式、運(yùn)行參數(shù)對(duì)熱耗率的影響,采取高精度測(cè)試儀表及嚴(yán)格的系統(tǒng)隔離措施,計(jì)算不明泄漏量,確保性能試驗(yàn)精度。q t =q n +q t(2q n =q t1+q tq n=q tC(3式中:q t 為試驗(yàn)工況參數(shù)下的機(jī)

5、組熱耗率;q n 為把試驗(yàn)工況參數(shù)修正到額定工況參數(shù)后的機(jī)組熱耗率;q t 為由于試驗(yàn)工況參數(shù)偏離額定工況參數(shù)使得機(jī)組熱耗61研究論文熱力發(fā)電2003(5率增加值。C 為總的試驗(yàn)工況參數(shù)修正系數(shù),即:C =1+ q t q np 01+q t q nt 01+q tq np r 1+q tq nt r1+q tq nt fw1+q tq np c(4式(4表示可控參數(shù)(主蒸汽壓力p 0、主蒸汽溫度t 0、再熱蒸汽壓損p r 、再熱蒸汽溫度t r 、給水溫度t fw 、真空p c 偏離額定工況參數(shù)引起機(jī)組熱耗率變化的修正系數(shù)。這些修正系數(shù)可以用制造廠(chǎng)家提供的參數(shù)修正曲線(xiàn),或用美國(guó)AS ME 標(biāo)準(zhǔn)

6、推薦的參數(shù)修正曲線(xiàn),或通過(guò)汽輪機(jī)組詳細(xì)熱力計(jì)算,以及通過(guò)熱力學(xué)簡(jiǎn)化計(jì)算得到。機(jī)組正常運(yùn)行時(shí),監(jiān)測(cè)機(jī)組實(shí)時(shí)熱耗率的目的是為了及時(shí)評(píng)價(jià)機(jī)組運(yùn)行管理水平。式(2可以寫(xiě)成:q t =q n +q t =q n (1+q tq n=C q n(5式中:q t 為運(yùn)行工況參數(shù)下機(jī)組運(yùn)行熱耗率;q n 為額定工況參數(shù)下機(jī)組的設(shè)計(jì)熱耗率,C 為總的試驗(yàn)工況參數(shù)修正系數(shù)。運(yùn)行工況下熱耗率值是隨著機(jī)組負(fù)荷、設(shè)備完好狀況及參數(shù)變化的。1臺(tái)機(jī)組投產(chǎn)后在一定的運(yùn)行周期內(nèi),只要機(jī)組設(shè)備結(jié)構(gòu)不發(fā)生改變,以及未發(fā)生機(jī)組損傷等情況,機(jī)組的設(shè)計(jì)性能基本維持不變。若機(jī)組運(yùn)行方式?jīng)]有改變,則機(jī)組設(shè)計(jì)熱耗率只受到機(jī)組運(yùn)行參數(shù)的影響。運(yùn)

7、行熱耗率與該工況下設(shè)計(jì)熱耗率值之差,就反映了機(jī)組運(yùn)行管理水平。各可控參數(shù)值也是隨機(jī)組負(fù)荷變化的,若機(jī)組在額定功率附近運(yùn)行,各參數(shù)應(yīng)達(dá)設(shè)計(jì)值;當(dāng)機(jī)組運(yùn)行工況嚴(yán)重偏離額定功率時(shí),各參數(shù)值應(yīng)根據(jù)詳細(xì)熱力計(jì)算或熱力性能試驗(yàn)確定1,2。3影響熱耗率實(shí)時(shí)計(jì)算準(zhǔn)確性因素在分析了機(jī)組熱耗率的影響因素后,重點(diǎn)對(duì)影響機(jī)組熱耗率實(shí)時(shí)計(jì)算準(zhǔn)確性的因素進(jìn)行分析。3.1主蒸汽流量從式(1可以看出主蒸汽流量的測(cè)量或計(jì)算精度,對(duì)熱耗率的影響成正比關(guān)系,即1%的流量誤差直接影響機(jī)組熱耗率1%,因此對(duì)主蒸汽流量的計(jì)量精度要求很高。由于蒸汽的可壓縮性,如果采用標(biāo)準(zhǔn)節(jié)流孔板,測(cè)量其差壓值換算成流量,再進(jìn)行蒸汽密度修正的方法,其精度較

8、低。并且,隨著汽輪機(jī)組容量增大和初參數(shù)提高,在主蒸汽管道上加裝節(jié)流孔板,會(huì)增加額外的節(jié)流損失。因而,大型汽輪機(jī)組測(cè)量主蒸汽流量是通過(guò)以下間接測(cè)量方法得到。(1對(duì)單元制機(jī)組而言,在最末高加與鍋爐間的給水管道上,安裝節(jié)流孔板測(cè)量給水流量,然后換算成主蒸汽流量,即:D 0=D fw +D ed -D ab (6式中:D fw 為鍋爐給水流量;D ed 為過(guò)熱蒸汽減溫水流量;D ab 為鍋爐排污流量(定排和連排之和。常規(guī)熱力性能試驗(yàn)中的主蒸汽流量計(jì)量均采用此方法,但直接把它應(yīng)用于熱耗率實(shí)時(shí)計(jì)算中,會(huì)產(chǎn)生較大的誤差。這是因?yàn)?1當(dāng)投過(guò)熱蒸汽減溫水時(shí),噴水量轉(zhuǎn)換成汽輪機(jī)做功的蒸汽量有1個(gè)滯后效應(yīng),使式(6

9、所得主蒸汽流量產(chǎn)生一個(gè)不真實(shí)的躍變,從而,機(jī)組熱耗率也產(chǎn)生一個(gè)不真實(shí)的躍變;2鍋爐排污流量的實(shí)時(shí)監(jiān)測(cè)也較困難。(2通過(guò)測(cè)量調(diào)節(jié)級(jí)后(監(jiān)視段壓力,利用Flugel 公式計(jì)算主蒸汽流量并作適當(dāng)修正,則變工況運(yùn)行時(shí)主蒸汽流量為:D 01=D 0p 11p 1(7式中:D 0為額定(設(shè)計(jì)工況時(shí)的主蒸汽流量;p 1為額定(設(shè)計(jì)工況時(shí)的調(diào)節(jié)級(jí)后壓力;p 11為變工況運(yùn)行時(shí)的調(diào)節(jié)級(jí)后壓力。假定汽輪機(jī)通流部分葉片沒(méi)有發(fā)生腐蝕、結(jié)垢、斷裂等情況,額定(設(shè)計(jì)工況時(shí)C =D 0p -1l 為定值,通過(guò)熱力性能試驗(yàn)對(duì)其進(jìn)行修正。這樣式(7為:D 01=C p 11(8在實(shí)際使用時(shí),還需用調(diào)節(jié)級(jí)后溫度及負(fù)荷進(jìn)行修正。這

10、樣,在正常運(yùn)行工況范圍內(nèi)(不包括機(jī)組的起、停工況,主蒸汽流量可以滿(mǎn)足熱耗率實(shí)時(shí)計(jì)算的需要。3.2再熱蒸汽流量再熱蒸汽流量是通過(guò)回?zé)嵯到y(tǒng)熱平衡計(jì)算求得。利用進(jìn)入各高加的抽汽壓力、溫度和進(jìn)、出高加的給水壓力、溫度與流量,通過(guò)回?zé)嵯到y(tǒng)熱平衡計(jì)算,求得高壓缸各級(jí)抽汽流量。這樣,再熱蒸汽管道冷段流量即高壓缸排汽流量,為主蒸汽流量減去高壓缸各級(jí)抽汽量,再熱蒸汽管道熱段流量為再熱蒸汽管道冷段流量加上再熱器減溫水噴水量。3.3汽輪機(jī)末級(jí)排汽焓值在汽輪機(jī)熱耗率實(shí)時(shí)計(jì)算中,實(shí)時(shí)確定汽輪機(jī)末級(jí)排汽焓值一直是一個(gè)難題,原因是處于濕蒸汽區(qū)時(shí),71研究論文熱力發(fā)電2003(5其壓力和溫度不再是相互獨(dú)立參數(shù),且又不具備對(duì)汽

11、輪機(jī)內(nèi)蒸汽濕度實(shí)用的在線(xiàn)測(cè)量手段。末級(jí)排汽焓在機(jī)組系統(tǒng)熱平衡計(jì)算、汽輪機(jī)低壓缸效率等計(jì)算中,又是一個(gè)非常重要的參數(shù)。汽輪機(jī)末級(jí)排汽焓的實(shí)時(shí)計(jì)算方法歸納為以下幾種。(1能量平衡法由下式表達(dá):P el =(D 0h 0+D rh h rh -D rc h rc -D j h j -D c h c m el(9式中:D j 、h j 為各抽汽流量、焓值;D c 、h c 為排汽流量、焓值;m 、el 為機(jī)械、發(fā)電機(jī)效率。如果各抽汽參數(shù)都為過(guò)熱蒸汽,由式(9可以方便地計(jì)算出排汽焓值。但實(shí)際上有幾個(gè)低壓抽汽參數(shù)已進(jìn)入濕蒸汽區(qū),其焓值也不能用抽汽壓力和溫度來(lái)確定,所以需要迭代計(jì)算。此方法的不足之處是其他參

12、數(shù)測(cè)量誤差會(huì)累計(jì)在排汽焓值上,并且影響迭代計(jì)算的收斂性。(2外推法根據(jù)再熱蒸汽入口狀態(tài)點(diǎn)和在過(guò)熱區(qū)的各抽汽口的狀態(tài)點(diǎn)連線(xiàn)的變化規(guī)律,外推到濕蒸汽區(qū),得到濕蒸汽區(qū)的各抽汽焓值及排汽焓值。此方法概念簡(jiǎn)單、計(jì)算方便,但也有明顯的不足之處:1由于在再熱蒸汽入口之后,處在過(guò)熱蒸汽區(qū)的抽汽口較少,使得參與擬合的點(diǎn)數(shù)較少,精度較差。2過(guò)程線(xiàn)外推,即過(guò)程線(xiàn)斜率不變,也就是級(jí)的相對(duì)內(nèi)效率不變。實(shí)際情況熱力過(guò)程處于濕蒸汽區(qū)后,由于濕蒸汽損失及末級(jí)余速損失的存在,級(jí)的相對(duì)內(nèi)效率要明顯降低,熱力過(guò)程線(xiàn)斜率相對(duì)要平緩一些。(3外推能量平衡法先由外推法確定處于濕蒸汽區(qū)的抽汽及排汽焓值,再進(jìn)行系統(tǒng)能量平衡迭代計(jì)算。此方法具

13、有迭代收斂快、累計(jì)測(cè)量誤差小的優(yōu)點(diǎn)6,可很好滿(mǎn)足熱耗率實(shí)時(shí)計(jì)算的需要。3.4減溫水噴水調(diào)溫減溫水噴水調(diào)溫包括過(guò)熱器和再熱器的噴水調(diào)溫2種。由于噴水調(diào)溫結(jié)構(gòu)簡(jiǎn)單、操作方便、調(diào)溫降幅大等特點(diǎn),常被用作主要調(diào)溫手段,但會(huì)明顯增加熱耗率。過(guò)熱器減溫水源可以分為給水泵出口投入與最末高加出口投入2種,前者給水分流部分不流經(jīng)高加,水溫較低,降溫效果好,但由于降低了鍋爐給水溫度,熱耗率會(huì)增加。再熱器噴水減溫,只作為防止再熱蒸汽溫度超溫的安全措施。如果經(jīng)常使用,其熱耗率會(huì)增加較快。再熱器噴水對(duì)熱耗率的影響可通過(guò)式(1求得,也可以通過(guò)等效焓降法計(jì)算分析8。3.5熱耗率實(shí)時(shí)計(jì)算周期為了能實(shí)時(shí)了解汽輪機(jī)組的運(yùn)行情況,

14、往往希望熱耗率實(shí)時(shí)計(jì)算周期短一些,但計(jì)算周期不能過(guò)短,這是由于整個(gè)汽輪機(jī)組系統(tǒng)存在較大熱慣性和熱滯后現(xiàn)象,且計(jì)算周期過(guò)短會(huì)使機(jī)組因負(fù)荷變動(dòng)造成的過(guò)渡過(guò)程和擾動(dòng)引起參數(shù)波動(dòng),影響實(shí)時(shí)計(jì)算的準(zhǔn)確性。計(jì)算周期過(guò)長(zhǎng),會(huì)失去計(jì)算的實(shí)時(shí)性,且過(guò)長(zhǎng)時(shí)間的參數(shù)平均也會(huì)失去計(jì)算的真實(shí)性。實(shí)際運(yùn)行情況表明,以(58min 的參數(shù)平均值計(jì)算1次熱耗率實(shí)時(shí)值較為合理。4結(jié)論(1影響汽輪機(jī)組熱耗率指標(biāo)的因素主要有機(jī)組的本身性能、運(yùn)行方式、運(yùn)行參數(shù)及測(cè)量數(shù)據(jù)的不確定度,因此不僅要求采用新技術(shù)、新設(shè)備,更要加強(qiáng)機(jī)組運(yùn)行的科學(xué)管理。(2機(jī)組熱耗率實(shí)時(shí)計(jì)算與熱力性能試驗(yàn),從目的到方法有其共同點(diǎn),也有很多不同之處。熱力性能試驗(yàn)的

15、目的是檢驗(yàn)機(jī)組的設(shè)計(jì)、制造質(zhì)量,機(jī)組熱耗率實(shí)時(shí)計(jì)算的目的是更科學(xué)地指導(dǎo)機(jī)組的運(yùn)行和管理。(3主蒸汽流量和再熱蒸汽流量計(jì)算、汽輪機(jī)排汽焓確定及計(jì)算周期是熱耗率實(shí)時(shí)計(jì)算中必須要解決的關(guān)鍵點(diǎn),將直接影響實(shí)時(shí)計(jì)算的可信度。參考文獻(xiàn)1任浩仁,李蔚,盛德仁,等.火電機(jī)組變工況下運(yùn)行指標(biāo)應(yīng)達(dá)值的分析J .中國(guó)電機(jī)工程學(xué)報(bào),1999,19(9:5052,56.2盛德仁,任浩仁,李蔚,等.運(yùn)行工況下汽輪機(jī)組主要參數(shù)應(yīng)達(dá)值的數(shù)值分析J .熱力發(fā)電,2000,(3:2830,58.3金生祥,杜霄龍.汽輪機(jī)運(yùn)行熱耗的偏差算法J .華北電力技術(shù),1997,(12:1417.4翦天聰.汽輪機(jī)最優(yōu)經(jīng)濟(jì)運(yùn)行M.北京:水利電力

16、出版社,1988.5盛德仁,任浩仁,陳堅(jiān)紅,等.汽輪發(fā)電機(jī)組DCS 系統(tǒng)在線(xiàn)性能計(jì)算程序的剖析及改進(jìn)J .浙江大學(xué)學(xué)報(bào)(工學(xué)版,2000,34(6:647650.6任浩仁,盛德仁,盧學(xué)鋒,等.汽輪機(jī)在線(xiàn)性能計(jì)算中的排汽焓的確定J .動(dòng)力工程,1998,18(6:1 4.7王興平.參數(shù)和系統(tǒng)對(duì)汽輪發(fā)電機(jī)組運(yùn)行經(jīng)濟(jì)性的影響J .動(dòng)力工程,1997,17(3:4852.8林萬(wàn)超.火電廠(chǎng)熱系統(tǒng)定量分析M.西安交通大學(xué)出版社,1985.81研究論文熱力發(fā)電2003(5THERMAL POWER GENERATIONV ol.32N o.5May 2003Contents &AbstractsTH

17、E ENVIR ON MENTA L VA L UE OF POWER GENERATION B Y USING NATURA L G AS Zhou H ao et al(2The traditional environmental imp act assessment (EIAh adn t convert the environmental benefits o f pow er generation by using natural gas into currency ,resulting in gratuitous oc 2cup ation o f their environmen

18、tal value (EV .By using the theory o f environmental economics ,an assessment o f the EV for pow er generation by using natural gas h as been carried out.The results show th at the EV o f pow er generation with natural gas can reach to R MB 89.639yu an/(MW h,providing b asis for reference to the EV

19、trading in the pow er m ar 2ket.STU DY ON POWER GENERATION COST AN D BI DDING PRICES OF SUPP LYING E LECTRICIT Y FR OM THER MA L POWER P LANT G ao Bo et al(6The cost o f a pow er plant include coal consumption ,m aintenance and other monetary expenses ,they should all be considered in cost analysis.

20、The energy consumption ch aracters o f m ain equipments and entire unites in a pow er plant h ave been analysed ,the cost ch aracteristic curves and some m ain influencing factors being studied.The relationship betw een aver 2age and m arginal costs ,their role in price bidding ,and some questions m

21、ust p ay attention in w orking out cost ch aracteristic curves being also analysed.The results m ay be useful for reference to carrying out cost ch aracter analysis and practical use in pow er plants.DEVE LOPMENT AN D APP LICATION OF SERVICE -LIFE MANAGEMENT TECHN OLOG Y FOR IMPORTANT PARTS OF THER

22、2MA L POWER P LANTS Li Yaojun(9Three aspects including in the expoitatively developed service -li fe m anagement technology for important p arts in therm al pow er plants are as follow s :service -li fe o f boiler tubes ,service -li fe o f boiler p arts ,and service -li fe o f steam turbines.On the

23、b asis o f large amount o f experiments and analyses ,evalu ation method and calculation model for service -li fe o f important p arts in tberm al pow er plants with the aim o f engineering application h ave been put forw ard ,including a series o f correlated qu antitative evalu ation techniques ,m

24、onitor 2ing h aedw ares ,di agnotic so ftw ares ,stand ards and guiding regulations;b ased on integrating and blazing new trails ,technical platform so ftw are o f a service -li fe m anagement system with initi ative know -how property right regarding important p arts o f therm al pow er plant ,such

25、 as boiler tubes ,m ain boiler p arts ,and steam turbines ,h as been designed and de 2veloped firstly in our country;a ling -term service -li fe m anagement mode o f pow er generation equipments ,combining on -line monitoring with by -p ass line monitoring ,h as been established in our country.The i

26、mplementation o f a complete set o f techniques and monitoring system for service -li fe m anagement h as been success fully realized in tw o pow er plants o f demonstative projects at the first time ,h aving extremely obvious effectiveness.STU DY ON MATHEMATIC MODE L OF PIPING -MAIN SCHEME CIRCU LA

27、TING WATER SYSTEM AN D SOL UTION METH OD THEREOF Cheng Maohu a et al(13The m athem atic model o f du al -piping -m ain scheme circulating w ater system at N anjing Pow er Plant w as established.Through analysing the topology structure o f the complex hy 2draulic piping netw ork system and intruducin

28、g virtural flow resistance ,the said circulating w ater system w as decomposed into simple hydraulic piping systems ,a key problem o f the piping -m ain scheme circulating w ater system in economical operation w as solved ,providing an effective method for analysing complex piping -m ain scheme syst

29、ems.ANA LYSIS AN D REA L -TIME CA LCU LATION OF SPECIFIC HEAT CONSU MPTION FOR STEAM TURBINE UNIT Sheng Deren et al(16The influencing factors upon speci fic heat consumption o f steam turbine unit h ave been summ arized and analysed ,the similarities and di fferences betw een real -time perform ance

30、 cal 2culation and therm al perform ance experiments being comp ared ,the m ain influencing factors and p arameters upon real -time calculation accuracy o f speci fic heat consumption being emph atically analysed ,providing theoretic b asis for implementing the system o f real -time pow er -generati

31、ng cost cunting in pow er plants.STU DY ON THE PARTIA L INCREMENT METH OD FOR OPTIMIZING PERFOR MANCE ANA LYSIS OF UTI LIT Y BOI LERS Wu Zhiqun et al(19A p arti al increment method o f perform ance di agnosis technology h as been put forw ard.The influence o f boiler operating p arameters vari ation

32、 due to ch anging the operation mode upon the economic aspect o f said boiler being qu antitatively analysed.Similarity and di fference betw een the conventional method and the p arti al increment method h ave been com 2p ared ,the result obtained is as follow s :the calculation accuracy o f p arti

33、al increment method being higher th an th at o f conventional method.EXPERTMENTA L STU DY ON G AS -SOLI D TWO -PH ASE F LOW WITH STR ONG LY SWIR LING TURBU LENCE Su Yaxin et al(22T aking CFB as b ackground o f application ,a study on strongly swirling turbulence o f gas -solid tw o -ph ase flow in a

34、 sep arator with a squ are cross -section h as been carried out by using a three -dimensional laser -b ased p articles dynamic analyser (3D -PA D.The results show:(1the distribution o f swirling flow field in the said squ are -sh aped sep arator h as a forced swirl in the centre ,but a qu asi -free

35、swirl near the side w all ,and a p arti al swirl existing in the place o f edge -angle.P articles mutu al collision in the place o f edge -angle m akes the qu asi -laminar flow pulsation there to be strengthened ,the dynamic energy o f the turbulence and the strength o f p arti al turbulence near th

36、e edge -angle to obtain a comp aratively large value ,consuming large amount o f energy ,being o f benefit to p articles sep aration at the edge -angle ;(2Above the sep arator ,the m ax value o f average falling velocity along the vertical direction is near to the right side o f the flow -guiding co

37、ne (w hile the inlet is at the leftside.I n the medium and low er -p art o f the sep arator ,the m ax falling velocity is situ ated at the right w all surface o f the sep arator.The direction o f velocity in the central p art o f the cross -section is upw ard ,and recirculation occurs here.STU DY ON

38、 TECHNICA L RETR OFIT OF FUE L COA L PU L VERIZE D SYSTEM REG AR DING 130t/h BOI LERS IN YI LI THER MA L POWER P LANT N o.2G uo hu aib ai et al(27A fter putting the tittle boilers into operation.troublesome problems ,such as insu fficient output cap acity o f the coal pulverized system ,low load cap

39、 ability o f said boilers ,and slag 2ging in the furnace etc.,h ave been existing in a very long period o f time ,leading the furnace outlet flue gas temperature to be above 200higher th an the desighed value ,and hot air temperature to reach 550,hence ,the units can only be operated under low load

40、condition ,and the time o f consecutive operation being short.Throw gh analysis and testing o f the said coal pulverized system ,qu ality o f fuel coal ,and combustion conditions etc.effective debugging and retro fitting h ave been carried out ,m aking the said problems to be satis 2factorily resolved.KIN DS AN D TECHNICA L FEATURES OF THE STARTING -UP SYSTEM FOR