新型W火焰低氮燃烧系统开发与应用
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摘要
为解决W型火焰锅炉NO_x排放浓度高的问题,基于煤燃烧的NOx生成与还原机理,提出了煤粉预分离浓缩和空气深度分级的新型直流型W火焰低氮燃烧系统,研究了燃尽风率、煤粉浓缩、二次风分配等因素对炉内空气动力场、燃烧及NO_x排放的影响,并对2个电厂的300 MW级亚临界机组W火焰锅炉进行了低氮燃烧改造。改造后的实测结果表明,采用优化的新型W火焰低氮燃烧系统后,当燃用Vdaf=13%~14%贫煤、机组负荷在160~320 MW时,锅炉的NO_x排放浓度由改造前的1 200 mg/m~3左右降至564~680 mg/m~3。
In order to solve the problem of high NOxemission concentration of W-flame boiler,a new type low-NOx W-flame combustion system with pulverized coal pre-separator and air-staging was proposed based on the mechanism of NOx formation and reduction of coal combustion.Effects of key factors,such as over fire air( OFA) rate,coal concentration and secondary air distribution,on aerodynamic field,coal combustion and NOxemission were studied.The new low-NOxW-flame combustion system was designed and optimized in two low-NOxretrofit projects of 300 MW subcritical boiler of thermal power plants. Test results show that boiler NOxemission is 564-680 mg/m~3 when using lean coal with dry ash-free basis volatile 13%-14%,and the unit load is between 160 MW and 320 MW,which is significantly reduced compared with the original emission about 1 200 mg/m~3.
In order to solve the problem of high NOxemission concentration of W-flame boiler,a new type low-NOx W-flame combustion system with pulverized coal pre-separator and air-staging was proposed based on the mechanism of NOx formation and reduction of coal combustion.Effects of key factors,such as over fire air( OFA) rate,coal concentration and secondary air distribution,on aerodynamic field,coal combustion and NOxemission were studied.The new low-NOxW-flame combustion system was designed and optimized in two low-NOxretrofit projects of 300 MW subcritical boiler of thermal power plants. Test results show that boiler NOxemission is 564-680 mg/m~3 when using lean coal with dry ash-free basis volatile 13%-14%,and the unit load is between 160 MW and 320 MW,which is significantly reduced compared with the original emission about 1 200 mg/m~3.
引文
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[17]程芳琴.低热值煤燃烧污染控制技术及原理[M].北京:科学出版社,2017.
[18]李振山,张志,陈登高.煤粉燃烧中NOx的预测:模型开发及Fluent实现[J].煤炭学报,2016,41(10):2426-2433.LI Zhenshan,ZHANG Zhi,CHEN Denggao.Prediction of NOx during pulverized coal combustion:Model development and its implementation with Fluent[J].Journal of China Coal Society,2016,41(10):2426-2433.
[19]张山鹰,谢佳,周武,等.一种“W”火焰锅炉燃烧设备:CN201220097451.8[P].2012-10-24.
[20]朱哮水,戴维葆.2种超临界W火焰锅炉技术特点比较[J].热力发电,2014,43(1):11-14,25.ZHU Xiaoshui,DAI Weibao.Technical features comparison of two supercritical unit W flame boilers[J].Thermal Power Generation,2014,43(1):11-14,25.
[21]刘鹏远,张海,申浩树,等.W火焰锅炉无烟煤煤粉气流着火特性[J].煤炭学报,2016,41(10):2466-2472.LIU Pengyuan,ZHANG Hai,SHEN Haoshu,et al.Anthracite ignition characteristics in an arch-fired boiler with slot burners[J].Journal of China Coal Society,2016,41(10):2466-2472.
[2]崔村丽.我国煤炭资源及其分布特征[J].科技情报开发与经济,2011,21(24):181-182.CUI Cunli.China's coal resources and their distribution characteristics[J].Sci-tech Information Development&Economy,2011,21(24):181-182.
[3]谢克昌.煤的结构与反应性[M].北京:科学出版社,2002.
[4]张雪,赵明,白雪峰.几种不同变质程度煤的热重分析研究[J].化学与粘合,2016,38(1):30-35,46.ZHANG Xue,ZHAO Ming,BAI Xuefeng.Study on the thermogravimetric analysis of several kinds of coals with various metamorphic grades[J].Chemistry and Adhesion,2016,38(1):30-35,46.
[5]汪华剑.W型火焰锅炉燃烧检测与优化研究[D].武汉:华中科技大学,2010.
[6]张汀.我国W火焰锅炉的运行现状及问题分析[J].应用能源技术,2013(8):19-21.ZHANG Ting.Analysis of present situation and problems during the operating of W-flame boiler in China[J].Applied Energy Technology,2013(8):19-21.
[7]柳宏刚,白少林.现役各类W火焰锅炉NOx排放对比分析研究[J].热力发电,2007,36(3):1-4.LIU Honggang,BAI Shaolin.Comparison and analytical study on NOxemission from various W-shaped flame boilers in service[J].Thermal Power Generation,2007,36(3):1-4.
[8]许传凯.低挥发分煤的燃烧与“W”型火焰锅炉若干问题研究[J].中国电力,2004,37(7):37-40.XU Chuankai.Several problems with the combustion of low-volatile coal and W-flame boiler[J].Electric Power,2004,37(7):37-40.
[9]苏宏亮,阎维平,高正阳,等.350 MW机组W火焰锅炉燃烧优化试验与性能预测[J].热力发电,2014,43(3):30-36.SU Hongliang,YAN Weiping,GAO Zhengyang.Combustion optimization test and performance prediction for a 350 MW unit W-flame boiler[J].Thermal Power Generation,2014,43(3):30-36.
[10]苗长信,王建伟,车刚.600 MW“W”火焰锅炉降低NOx的调试分析[J].山东电力技术,2004(2):6-9,22.MIAO Changxin,WANG Jianwei,CHE Gang.The commissioning analysis on NOxreduction in 600 MW W-flame boiler[J].Shandong Electric Power,2004(2):6-9,22.
[11]刘武成.我国“W”型火焰拱式燃烧炉的运行和改进方向的探讨[C]//动力工程学会锅炉专委会大型锅炉运行性能研讨会文集.2002.
[12]MARK T K.The release of nitrogen oxides during char combustion[J].Fuel,1997,76(6):457-473.
[13]徐旭常,吕俊复,张海.燃烧理论与燃烧设备[M].北京:科学出版社,2012.
[14]徐旭常,周力行.燃烧技术手册[M].北京:化学工业出版社,2008.
[15]车得福.煤氮热变迁与氮氧化物生成[M].西安:西安交通大学出版社,2013.
[16]曹欣玉,牛志刚,应凌俏,等.无烟煤燃料氮的热解析出规律[J].燃料化学学报,2003,31(6):538-542.CAO Xinyu,NIU Zhigang,YING Lingqiao,et al.Releasing of fuel-nitrogen during blind coal pyrolysis[J].Journal of Fuel Chemistry and Technology,2003,31(6):538-542.
[17]程芳琴.低热值煤燃烧污染控制技术及原理[M].北京:科学出版社,2017.
[18]李振山,张志,陈登高.煤粉燃烧中NOx的预测:模型开发及Fluent实现[J].煤炭学报,2016,41(10):2426-2433.LI Zhenshan,ZHANG Zhi,CHEN Denggao.Prediction of NOx during pulverized coal combustion:Model development and its implementation with Fluent[J].Journal of China Coal Society,2016,41(10):2426-2433.
[19]张山鹰,谢佳,周武,等.一种“W”火焰锅炉燃烧设备:CN201220097451.8[P].2012-10-24.
[20]朱哮水,戴维葆.2种超临界W火焰锅炉技术特点比较[J].热力发电,2014,43(1):11-14,25.ZHU Xiaoshui,DAI Weibao.Technical features comparison of two supercritical unit W flame boilers[J].Thermal Power Generation,2014,43(1):11-14,25.
[21]刘鹏远,张海,申浩树,等.W火焰锅炉无烟煤煤粉气流着火特性[J].煤炭学报,2016,41(10):2466-2472.LIU Pengyuan,ZHANG Hai,SHEN Haoshu,et al.Anthracite ignition characteristics in an arch-fired boiler with slot burners[J].Journal of China Coal Society,2016,41(10):2466-2472.