利用CFD流场分析对锅炉SCR脱硝烟道接口直角弯头改造
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摘要
由于部分火电厂燃煤锅炉采用低氮改造+SNCR或SCR脱硝技术的氮氧化物排放浓度达不到现行超低排放标准,因此就必须采用脱硝效率更高SCR脱硝技术对原有系统进行改造,由于SCR对烟气温度要求和厂区场地限制,SCR脱硝系统烟气的引出和接入位置空间狭小(2m～4m),进出烟道甚至要共用烟道壁板,这样就产生烟气偏流和烟道内积灰现象。本文首先以某燃煤锅炉烟气脱硝工程的直角弯头改造为研究对象,采用FLUENT数值模拟方法研究直角弯头烟气的流动分布,在此基础上,对导流板进行优化设计,直角弯头在改造前积灰严重,影响锅炉工况,经改造后积灰状况得到极大改善,保证了系统正常运行。
Because the emission concentration of NOx from coal-fired boilers in some thermal power plants can not meet the current ultra-low emission standard by using low nitrogen retrofitting + SNCR or SCR denitrification technology, it is necessary to adopt SCR denitrification technology with higher denitrification efficiency to retrofit the original system. Due to the requirements of SCR on flue gas temperature and site limitations,the space of exhaust gas extraction and access for SCR denitrification system is narrow(2m-4m),the inlet and outlet flues even share the flue wall panels, which results in the phenomenon of flue gas deviation and ash accumulation in the flue. In this paper, the right-angle elbow of a coal-fired boiler flue gas denitrification project is taken as the research object, and FLUENT numerical simulation method is used to study the flue gas flow distribution of the right-angle elbow. On this basis, the guide plate is optimized. The right-angle elbow has serious ash accumulation before the transformation, which affects the working condition of the boiler. Great improvement has been made to ensure the normal operation of the system.
Because the emission concentration of NOx from coal-fired boilers in some thermal power plants can not meet the current ultra-low emission standard by using low nitrogen retrofitting + SNCR or SCR denitrification technology, it is necessary to adopt SCR denitrification technology with higher denitrification efficiency to retrofit the original system. Due to the requirements of SCR on flue gas temperature and site limitations,the space of exhaust gas extraction and access for SCR denitrification system is narrow(2m-4m),the inlet and outlet flues even share the flue wall panels, which results in the phenomenon of flue gas deviation and ash accumulation in the flue. In this paper, the right-angle elbow of a coal-fired boiler flue gas denitrification project is taken as the research object, and FLUENT numerical simulation method is used to study the flue gas flow distribution of the right-angle elbow. On this basis, the guide plate is optimized. The right-angle elbow has serious ash accumulation before the transformation, which affects the working condition of the boiler. Great improvement has been made to ensure the normal operation of the system.
引文
[1] Pudasainee D, Lee S J, Lee S H, et al. Effect of selective catalytic reactor on oxidation and enhanced removal of mercury in coal fired power plants[J]. Fuel,2010, 89(4):804-809.
[2] Yang Hongmin, Pan Weiping. Transformation of mercury speciation through the SCR system in power plants[J]. Journal of Environmental Sciences, 2007,19(2):181-184.
[3]杨卫娟,周俊虎,刘建忠,等.选择催化还原SCR脱硝技术在电站锅炉的应用[J].热力发电,2005(9):10-14.
[4]孟德润,赵翔,杨卫娟,等.200MW水煤浆锅炉的低NOx燃烧试验[J].动力工程,2007,27(3):341-343.
[5]崔龚编.燃煤发电厂粉煤灰气力输送系统[M].北京:中国电力出版社,2005
[2] Yang Hongmin, Pan Weiping. Transformation of mercury speciation through the SCR system in power plants[J]. Journal of Environmental Sciences, 2007,19(2):181-184.
[3]杨卫娟,周俊虎,刘建忠,等.选择催化还原SCR脱硝技术在电站锅炉的应用[J].热力发电,2005(9):10-14.
[4]孟德润,赵翔,杨卫娟,等.200MW水煤浆锅炉的低NOx燃烧试验[J].动力工程,2007,27(3):341-343.
[5]崔龚编.燃煤发电厂粉煤灰气力输送系统[M].北京:中国电力出版社,2005