刘 琦1，孙文杰2，杨宝宏3，贾晖杰3
(1.西安热工研究院有限公司，陕西西安 710032;2.西安电力高等专科学校，陕西西安 710032;
3.河津发电厂，山西河津 043300)
[摘 要] 通过试验分析了某电厂300MW机组锅炉所配双进双出钢球磨煤机辅助风投运对锅炉排烟温度的影响，结果表明，锅炉运行期间只要磨煤机一次风管不堵管，就无需投入磨煤机辅助风，辅助风仅在启动前和停磨煤机后吹扫管道时投入即可。不投辅助风，锅炉效率可提高0.69个百分点。
[关键词] 300MW机组；锅炉；磨煤机；辅助风；排烟温度
[中图分类号]T K223.25 [文献标识码]B [文章编号]10023364(2006)08003102
某电厂2×300MW机组锅炉为H G1056/17.5 YM21型亚临界、一次中间再热、平衡通风、固态排渣、自然循环汽包炉。自投产以来，排烟温度较高, 2005年9月西安热工研究院有限公司对该锅炉进行了燃烧调整试验，通过试验出了锅炉排烟温度高的原因。
1 锅炉设备概况
锅炉炉膛宽14048mm，深12468mm，高53860 mm(从汽包中心线至顶棚过热器中心线)。炉膛容积热负荷Q v为421000kJ/(m3・h)，炉膛断面热负荷Q a 为17.706×106kJ/(m2・h)，燃烧器区域壁面热负荷Q y为5.198×106kJ/(m2・h)。
锅炉采用四角切圆燃烧方式，逆时针旋转的假想切圆直径为d880mm。整组燃烧器为一、二次风间隔布置，四角均等配风。在水平浓淡燃烧器顶部分别布置了2层O FA喷嘴反向切入，整组燃烧器可上下摆动30°(除OFA喷嘴)。锅炉自下而上共布置有AA、AB、BC、BD、CE、CF6层(每台磨煤机带2层一次风喷口)共24只煤粉燃烧器及AB、CD、EF3层共12只油。
每台锅炉配有3台福斯特惠勒公司生产的FW
D11D型双进双出钢球磨煤机，正压直吹式运行。磨煤机设容量备用，不设台数备用，设计煤粉细度R90为15%。
在通向每一根煤粉管道的辅助风管线上装有辅助风调节挡板，以便在正常运行期间保证流速，以及在启动前和停磨煤机后吹扫管道。
锅炉设备主要参数见表1，燃用煤煤质特性见表2。
表1 锅炉设备主要参数
项目BMCR BECR
过热蒸汽流量/t・h-110561007.75
过热器出口蒸汽压力/MPa17.517.41
过热器出口蒸汽温度/℃540540
再热蒸汽流量/t・h-1876.31834.14
再热器进口蒸汽压力/MPa 3.993 3.739
再热器出口蒸汽压力/MPa 3.757 3.572
再热器进口蒸汽温度/℃329323.7
再热器出口蒸汽温度/℃540540
省煤器进口给水温度/℃281.3278
排烟温度/℃135128.9
锅炉效率/%93.093.29
技术交流
收稿日期: 20051107
表2 设计煤种和校核煤种特性
项目设计煤高值煤低值煤试验煤质
工业分析收到基低位发热量
Q net.ar/MJ・kg-1
20.0622.6819.0617.39收到基全水分M t/% 4.3 4.2 4.4 6.6空气干燥基水分M ad/%0.88 1.060.72 2.31收到基灰分A ar/%31.4625.4837.4536.45干燥无灰基挥发分V daf/%27.8726.5028.8627.14
元素分析收到基碳C ar/%54.6060.8448.4645.20收到基氢H ar/% 2.95 2.97 2.93 2.77收到基氧O ar/% 4.18 3.81 4.59 6.46收到基氮N ar/%0.850.790.820.72收到基硫S ar/% 1.81 1.93 1.42 1.80
哈氏可磨系数H GI857687
灰变形温度D T(T1)/℃≥1500≥1500≥1500
2 试验结果
辅助风来自冷风管道，其投入虽可提高一次风速，但大量的冷风投入一次风管，会降低一次风风温，推迟煤粉着火，并增加风机电耗，对机组经济运行不利。在保证一次风管不堵管的情况下应尽量少投磨煤机辅助风。试验分磨煤机辅助风门开度100%、50%、0%3个工况，试验结果见表3。
表3 变磨煤机辅助风量试验结果
项目
磨煤机辅助风开度100%50%0%
电负荷/MW301.9300.1300.1主蒸汽流量/t・h-1978.0969.0976.9主蒸汽温度/℃539.3540.6533.8主蒸汽压力/MPa17.0217.0817.13一级减温水流量/t・h-1 5.90 2.39 2.39二级减温水流量A/t・h-1 2.810.00.0二级减温水流量B/t・h-112.98 5.19 2.91高温过热器出口A/℃539.0537.2526.9高温过热器出口B/℃541.5544.4542.7再热蒸汽出口温度/℃538.1539.2535.7再热蒸汽出口压力/MPa 3.42 3.39
3.37再热器减温水流量A/t・h-17.778.66 2.84再热器减温水流量B/t・h-1 1.03 5.4 3.09二次风量A/t・h-1436442437二次风量B/t・h-1418420417空气预热器进口平均氧量/% 3.72 3.78 2.95一次热风管道母管压力A/kPa11.8512.011.83一次热风管道母管压力B/kPa11.7211.8411.71
项目
磨煤机辅助风开度
100%50%0%
空气预热器入口烟气温度A/℃365.5354.5350.6
空气预热器入口烟气温度B/℃355.2347.7343.7
空气预热器入口一次冷风温度
A/℃
44.342.141.6
空气预热器入口一次冷风温度
B/℃
42.640.539.1
空气预热器入口二次冷风温度
A/℃
33.831.830.3
空气预热器入口二次冷风温度
B/℃
34.232.030.0
空气预热器出口烟气温度A/℃135.7128.7116.8
空气预热器出口烟气温度B/℃137.9131.5117.9
空气预热器出口一次热风温度
A/℃
322.5312.3304.5
空气预热器出口一次热风温度
B/℃
321.9313.6306.1
空气预热器出口二次热风温度
A/℃
325.1315.6309.0
空气预热器出口二次热风温度
B/℃
322.9315.1309.2
一次风机导叶开度A/%100.071.946.1
一次风机导叶开度B/%98.068.744.6
一次风机电流A/A75.4071.9464.51
一次风机电流B/A77.0775.1967.02
一次风机出口压力A/kPa12.6012.6212.60
一次风机出口压力B/kPa12.5912.6012.59
二次风机导叶开度A/%57.755.854.6
二次风机导叶开度B/%58.254.754.3
二次风机电流A/A40.5638.6037.44
二次风机电流B/A38.9836.6436.27
二次风机出口压力A/kPa 2.02 1.85 1.83
二次风机出口压力B/kPa 2.25 2.01 1.98
引风机导叶开度A/%49.146.242.3
引风机导叶开度B/%54.551.848.1
引风机电流A/A90.4489.4884.23
引风机电流B/A87.4684.9976.16
修正到设计进风温度时排烟温
度/℃
130.27124.94114.94
风机电耗(P/D)/kW290629222578
锅炉效率/%92.2592.6692.94从表3可见，磨煤机辅助风门开度由100%变至50%直到0%时，锅炉过热器和再热器减温水量逐渐降低，排烟温度也逐渐降低，且降低幅度较大。磨煤机
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技术交流
32 ()
可以采取以下防范措施:(1)投运高压厂用辅汽时先关闭疏水阀3，稍微开疏水阀2，观察缸温变化，待高压厂用辅汽投运正常后将疏水阀3、2全开。(2)在以后改造中建议将疏水阀3所在的疏水管重新接一路单独的疏水管去大气扩容器，防止高压厂用辅汽系统的疏水和蒸汽返回中压缸。 2.2 起动过程缸温异常下降
缸温异常下降的危害比缸温异常上升的危害更大，因为在温度下降时转子和汽缸的金属表面承受较大的拉伸应力，而金属拉伸应力的允许极限要比因温度上升产生的压缩应力的允许极限低得多，更容易使部件损坏。缸温大幅下降往往是汽轮机进水的反映，它会造成汽缸变形、机组振动增大,
:(1)汽缸本体疏
;
(2)高低压加热器泄漏，造成加热器满水倒回汽缸;(3)热态起动时轴封蒸汽参数偏低;(4)热态起动时疏水不充分或蒸汽参数偏低;(5)锅炉上水打压时电动主闸阀及其旁路阀不严，给水漏入高压主汽阀前；电动
给水泵中间抽头隔离阀不严及锅炉再热器减温水阀不严；高旁阀不严，给水进入再热器中，进而进入中压主汽阀和倒灌至高压缸排汽侧。对此采取了以下防范措施:
(1)机组停机及起动时就地检查各疏水阀的开启情况，尤其是高中压主汽阀前疏水和高压缸排汽逆止阀前后疏水以及排大气防腐阀的开启;
(2)注意监视加热器水位在正常范围内;
(3)保证轴封温度在正常范围内;
(4)锅炉上水打压时应关严电动主闸阀及其旁路阀，关闭电动给水泵中间抽头隔离阀，开启中间抽头总管放水阀，减少再热器的泄漏量;
(5)检查高压缸排汽逆止阀和高压缸倒暖电动阀及手动阀切实关闭;
(6)各疏水管的防腐阀打开，加大疏水排泄，防止疏水积聚返回汽缸内;
(7)凝汽器可稍微抽真空，加快疏水向凝汽器的排泄;
(8)机组起动时尤其是热态起动时，主、再热蒸汽及轴封管道要充分疏水,，冲转时选择合适的冲转参数保证蒸汽温度比缸温高50℃～80℃，并有
(9)锅炉上水打压时可关闭高压扩容器和本体扩容器的喷水隔离阀及旁路阀，防止扩容器水位高引起疏水不畅;
(10)密切监视缸温及盘车电流、转速的变化，发现异常及时作出判断，采取相应处理措施。
3 结 语
对机组起动过程中压缸温异常上升和下降的情况分别进行了分析。疏水管设计不合理引起起动时中压缸温度异常上升，而电动主闸阀及其旁路阀不严、电动给水泵中间抽头隔离阀不严及锅炉再热器减温水阀不严、锅炉高旁阀不严，使给水在起动时进入再热器，进而进入中压主汽阀和倒灌至高压缸排汽侧，引起缸温异常下降。针对以上原因提出了相应预防措施，对保障机组及相关设备的安全稳定运行取得了实效。
[参 考 文 献]
[1] 沈士一，庄贺庆，康松，等.汽轮机原理[M].北京：水利电
力出版社,1991.
[2] 吴季兰.汽轮机设备及系统[M].北京：中国电力出版社,
1998.
(上接第32页)
辅助风门开度为0%工况时的排烟温度较100%工况时平均下降15.33℃，且低于设计排烟温度128.9℃。引风机及一次风机电耗每小时下降了328kW・h，锅炉效率提高了0.69个百分点，煤耗至少下降2g/(kW・h)，机组经济性明显提高。
3 结 论
(1)在磨煤机辅助风门开度100%、50%、0%3种工况下，对某电厂300MW机组锅炉变磨煤机辅助风量对锅炉排烟温度的影响进行了试验，结果表明，磨煤机辅助风门开度为0%工况时的排烟温度较100%工况时平均下降15.33℃，锅炉效率提高了0.69个百分点，机组经济性明显提高。
(2)锅炉运行期间，在保证磨煤机一次风管不堵管的情况下，无需投入磨煤机辅助风，仅在启动前和停磨煤机后吹扫管道时投入即可。
技术交流
t hrough entropy equation in occurrence process of t he resistance ,which is deduced from steam condition equation of IAPWS IF 97.The result of
checking analysis shows t hat t he model can be used for calculating t he energy dissipation while steam passing t hrough a restrictive device.being more convenient and accurate t han using traditional met hod.
K ey w ords :t hermal power plant ;steam piping network ;available energy dissipation ;computing model ;entropy equation ;restrictive device in pipe 2line ;steam condition equation
STU DY ON B OI LER ’S OPERATION PERFORMANCE AN D OPTIMIZATION OF OX YGEN CONTENT IN F L UE G AS CAI Jie jin ,MA Xiao qian ,L IAO Yan fen (28)
……………
…………………………………………………………………………………Abstract :Study on optimization of oxygen content in flue gas at t he furnace outlet under operation condition of 200MW ,180MW ,and 160MW of a 200MW coal fired unit in one power plant has been carried out ,t he affecting regularity of oxygen content in flue gas upon t he operation performance of utility boiler being obtained.The result s show t hat t he corresponding optimal oxygen content to be 3.6%,3.8%,and 4.5%respectively ,t hese pa 2rameters providing reference basis for ecomomic operation of utility boilers.K ey w ords :boiler ;oxygen content in flue gas ;operation performance opti
mization
INF L UENCE OF PUTTING AUXI LIAR Y AIR OF DOUB LE IN LET AN D DOUB LE OUT LET COA L PU L VERIZER INT O OPERA 2TION UPON ECON OMIC BEHAVIOR OF THE B OI LER L IU Q i ,SUN Wen
jie ,YANG B ao hong et al(31)
………………………Abstract :Through test and analysis ,t he influence of putting auxiliary air of t he double inlet and double outlet coal pulverizer into operation upon ecom 2omic behavior of t he boiler for 300MW unit in one power plant has been obtained.The result s show t hat t he auxiliary air of coal pulverizer isn ’t nec 2essary to put into operation so lang as t he primary air pipe of t he pulverizer isn ’t plugged up during t he period of boiler operation ;t he auxiliary air of coal pulverizer can only put into operation before start
up or after shutdown of t he coal pulverizer for purging t he pipeline.
K ey w ords :boiler ;coal pulverizer ;auxiliary air ;economic behavior
ANA LYSIS OF UNUSUAL TEMPERATURE VARIATION CONCERNING ME DIUM PRESSURE C Y
L IN DER IN START UP
PR OCESS OF 330MW UNIT MADE B Y R OMANIA
MA W ang peng (33)
……………………………………………………………Abstract :For two 330MW unit s made by Romania and installed in Huadian Pucheng Power Generating Co Ltd ,unusual temperature variation concern 2
ing medium pressure cylinder has occurred in start up process of said unit s.The harmfulness resulting from unusual variation of cylinder tempera 2
ture has been analysed ,and t he causes leading to unusual variation of cylinder temperature being summarized ,and t hen corresponding preventive
measures being put forward.K ey w ords :330MW unit ;start up of t he mediumpressure cylinder ;temperature difference ;unusual cylinder temperature ;t hermal stress ;Pucheng
Power Plant
ANA LYSIS AN D REME DY OF VAL VE STEM LEAKAGE FOR HIGH PRESSURE MAIN STEAM VAL VE OF 300MW UNIT L I Jie ,TIAN Wen zeng (36)
…
……………………………………………………………………………………………………………Abstract :After retrofitting t he digital electro
hydraulic (DEH )Control System of t he steam turbine unit no.1in Dezhou Power Plant ,t he valve stem
leakage has occurred on t he highpressure main steam valve ,and t he causes leading to t he said leakage being analysed.Through adjust ment of t he t her 2mal control parameters ,t he valve stem leakage problem of t he main steam valve resulted from insufficient opening in hot state has been eliminated.K ey w ords :300MW steam turbine unit ;high pressure main steam valve ;valve stem leakage ;analysis ;remedy
ANA LYSIS AB OUT ECON OMIC BEHAVIOR IN OPERATION OF HIGH PRESSURE HEATER FOR 300MW UNIT CHEN Q ing hui (38)
…
…………
……………………………………………………………………………………………………………………Abstract :The abnormal phenomena appeared in operation of high pressure heater system for unit no.3and no.4in Zhanjiang Power Co Ltd have been analysed ,t he causes leading to high pressure heater failure being found out ,and retrofitting measures being put forward.Through test ,t he econom 2ic operation mode of t he high pressure heater system has also been determined.
K ey w ords :300MW unit ;high pressure heater ;terminal temperature difference ;economic behavior ;retrofitting measures
DESIGN AN D TEST OF RB CONTR OL FOR 300MW UNITS QU G u ang hao ,L IU Shu jie (42)
……………………………………Abstract :The control mode ,logic design ,and test situation of run back (RB )for 300MW unit in Huaneng Dezhou Power Plant have been presented.The RB of unit no.4has been successfully put into operation ,enhancing t he operation reliability and economic benefit of said unit.K ey w ords :300MW unit ,load
reducing at failure of auxiliary equipment ;RB control ;air fan ;steam
driven pump ;motor
driven pump
APPL ICATION OF REXA ACTUAT OR OPERATE D E LECTR O H YDRAU L IC G OVERNING SYSTEM ON RUSSIA MADE 145MW
TURBINE OF CO
GENERATION UNIT
FAN Zhi qiang ,CHEN F ang yi ,ZHAO Jian et al(45)
……………………………………Abstract :Unit no.1in Huaneng Beijing Thermal Power Plant is a 145MW extraction steam turbine manufactured by Ural Steam Turbine Factory in Russia ,and has adopted a governing system wit h co
existence of electric and hydraulic modes.In order to enhance t he level of automation ,t he said
governing system has been retrofitted by using technical scheme ,in which t he REXA astuator is tak
en as a changeover gear ,and t he force driven ac 2tuator as a servomotor ,obtaining satisfactory retrofit result ,providing new way for retrofitting t he governing system of similar type unit s.K ey w ords :REXA actuator ;electro
hydraulic control system ;extraction steam turbine
PR OB LEMS EXISTING IN “SS 6284DETERMINATION OF T OTA L SI L ICON ”AN D IMPR OVEMENT THERE OF TIAN Li ,WANG G u ang zhu,SUN Wei
w ei et al(49)
…………
………………………………………………………………………………Abstract :At t he time of measuring high concentration silicon ,t he existence of phosphor can result in a larger error.In order to eliminate defect s of t he said met hod ,a series of test have been carried out.Result s show t hat t he adjust ment of added dosage for conditioning agent can eliminate t he said er 2ror.After improvement ,t he said met hod to have better accuracy and precision.
