CFB锅炉分离器脱硝特性数值模拟研究  

Numerical simulation study on denitrification characteristics of CFB boiler separator

作　　者：王兴 乔杰 王东 王磊 张志强 林正根 WANG Xing;QIAO Jie;WANG Dong;WANG Lei;ZHANG Zhiqiang;LIN Zhenggen(ShanXi Research Institute of Huairou Laboratory,Taiyuan 030032,Shanxi China;State Key Laboratory of Low-carbon Smart Coal-fired Power Generation and Ultra-clean Emission,China Energy Science and Technology Research Institute Co.,Ltd.,Nanjing 210023,Jiangsu China;School of Electric Power,Civil Engineering and Architecture,Shanxi University,Taiyuan 030000,Shanxi China)

机构地区：[1]怀柔实验室山西研究院,山西太原030032 [2]低碳智能燃煤发电与超净排放全国重点实验室(国家能源集团科学技术研究院有限公司),江苏南京210023 [3]山西大学电力与建筑学院,山西太原030000

出　　处：《电力科技与环保》2024年第6期615-624,共10页Electric Power Technology and Environmental Protection

基　　金：国家重点研发计划项目(2022YFC3701504)。

摘　　要：为了揭示循环流化床锅炉旋风分离器的脱硝特性,本文采用数值计算的方法,以某300 MW循环流化床锅炉为研究对象,主要研究了尿素溶液喷枪安装数量及布置方式、尿素溶液雾化粒径、氨氮摩尔比以及锅炉负荷对SNCR脱硝效果的影响。结果表明,尿素喷枪数量及布置方式对氨氮在垂直方向的均匀混合有重要影响,喷枪数量为14支且采用双侧错层均匀布置时性能最佳;尿素溶液的粒径主要影响氨氮在水平方向的均匀混合程度,粒径为80μm时混合效果最好;氨氮摩尔比存在一个最佳范围,偏大或偏小都会带来不利影响,满负荷工况下的最佳氮氮摩尔比为1.2;脱硝效率随着负荷的减少而降低,在40%负荷以下时,由于烟气温度偏低,单独采用分离器SNCR脱硝方式无法满足超低排放需求。本文的研究结论对CFB锅炉的分离器脱硝系统设计及运行有一定的借鉴意义。To investigate the denitrification characteristics of a cyclone separator in a circulating fluidized bed boiler,a 300 MW circulating fluidized bed boiler is chosen as the subject of this study.The impact of various key parameters on denitration efficiency,including the number and arrangement of urea spray devices,urea particle size,NH3/NO mole ratios,and boiler load.The numerical results suggested that the quantity and arrangement of urea spray devices significantly influence the mixing uniformity of ammonia nitrogen vertically.The best performance was achieved when there are 14spray guns evenly distributed on both sides.Meanwhile,the particle size of the urea solution primarily affected the mixing horizontally,with the best mixing effect observed at a particle size of 80μm.There existed an optimal range for NH3/NO mole ratios,beyond which denitration efficiency decreases.The optimal nitrogen molar ratio under full load operating conditions was 1.2.Denitrification efficiency decreases continuously as the boiler load decreased.This leaded to a situation where,when the boiler load fell below 40%,removing NOx solely in the cyclone separator was insufficient to meet the requirement of ultra-low emissions due to low flue gas temperatures in the cyclone separator.The findings of this study provided valuable insights for the design and operation of the denitration system of CFB boiler separators.

关 键 词：循环流化床 SNCR 数值模拟 分离器脱硝 氨氮摩尔比 

分 类 号：TK01[动力工程及工程热物理]