摘要
针对某电厂超临界660 MW机组墙式切圆燃煤锅炉,通过在空气分级燃烧技术上运用富氧燃烧的方法,对炉内温度场以及NO_x排放特性进行了数值模拟研究。结果表明:在25%、28%、30%富氧工况下,30%富氧工况表现出与电厂实际空气工况运行下良好的一致性,且炉膛火焰充满度更好,比采用空气分级燃烧稳定;再循环烟气中高摩尔分数的CO_2与煤焦反应加剧了还原性气氛,且煤粉气流在还原区停留时间的增大提高了NO_x污染物向N_2的转化,减少了NO_x生成量;墙式切圆燃烧煤粉锅炉采用分级富氧燃烧后炉膛出口NO_x生成量由原来的236 mg/m^3降低为125 mg/m^3,较空气分级燃烧降低了47.03%。
Numerical simulation of NOx emission characteristics for a supercritical 660 MW unit wall type tangentially fired pulverized coal boiler were carded out. The influence of temperature field and NOx concentration in the furnace were studied by using the method of oxy-fuel combustion in the air staged combustion technology. The results show that, under oxy-fuel conditions with oxygen content of 25%, 28% and 30%, the operation situation of the boiler under 30% oxy-fuel condition shows good agreement with that under the actual air condition in the power plant, and the flame fullness and combustion stability is better than that using the air staged combustion. The reaction between the high concentration CO2 in flue gas recirculation and the char exacerbated the reducing atmosphere, and the increase of residence time of the pulverized coal flow in the reduction zone improves the transformation of NOx to N2, thus the NOx generation is reduced. After the staged oxy-fuel combustion technology is apllied, the NOx concentration at the furnace outlet reduces by 47.03%, which is from 236 mg/m3 to 125 mg/m3.
出处
《热力发电》
CAS
北大核心
2017年第5期63-68,共6页
Thermal Power Generation
基金
吉林省教育厅"十三五"科学技术研究项目(201680)~~
关键词
锅炉
墙式切圆燃烧
分级富氧燃烧
NOX排放
温度场
数值模拟
boiler, wall tangentially fired, staged oxy-fuel combustion, NOx emission, temperature field, numerical simulation
