摘要
针对某电厂660 MW四角切圆煤粉锅炉NOx排放高的问题,进行了增加分离燃尽风(separated overfire air,SOFA)的低氮改造。利用ANSYS FLUENT14.0软件进行了低氮改造后不同紧凑燃尽风(close-coupled overfire air,CCOFA)与SOFA配比下燃烧特性的数值模拟,研究了炉膛速度场、温度场、组分场和污染物分布的规律。主要结论如下:第一,炉内最高温度出现在CCOFA与SOFA配比为64∶112(风量单位为kg/s,下同)。第二,CCOFA与SOFA配比为64∶112时,炉膛出口温度最高,为1 537.2 K;当CCOFA与SOFA配比为56∶120时,炉膛出口温度最低,为1 511.1 K。第三,随着SOFA风量减小,炉膛出口NOx的质量浓度逐渐降低,在CCOFA与SOFA配比为64∶112时,炉膛出口NOx的质量浓度达到最小值为221.75 mg/m3(标准状况下),建议在实际运行中维持CCOFA与SOFA配比为64∶112。
In allusion to the problem of high emission of NOx of 660 MW tangentially fired boiler in some power plant, low nitrogen transformation of increasing separated overfire air （SOFA）is carried out. ANSYS FLUENT 14.0 software is used for numerical simulation on combustion characteristics with different closed-coupled overfire air （CCOFA）after low nitrogen transformation and distribution laws of furnace speed field, temperature field, species field and pollutants are studied. It is concluded firstly the highest temperature in the furnace occurs when CCOFA and SOFA matching is 64 ： 112 （ air volume u- nit is kg/s, the same below）. Secondly, when CCOFA and SOFA matching is 64 ： 112, the exit temperature of furnace is the highest at 1 537.2 K, while when CCOFA and SOFA matching is 56 ： 120, the exit temperature of furnace is lowest at 1 511.1 K. Thirdly, with decrease of SOFA air volume, NO, concentration at the exit of furnace reduces gradually, when CCOFA and SOFA matching is 64 ： 112, NOxconcentration at the exit of furnace reaches to the minimum value of 221.75 mg/m3 under standard state. Therefore, it is suggested to keep CCOFA and SOFA matching with 64 ： 112 in practical operation.
出处
《广东电力》
2016年第1期1-7,16,共8页
Guangdong Electric Power
基金
国家自然科学基金重点项目(51376161)
关键词
前后墙对冲
超超临界
NOx分布
数值模拟
变紧凑燃尽风
分离燃尽风
front-back wall hedge
ultra-supercritical
NOx distribution
numerical simulation
closed-coupled overfire air
separated overfire air
