摘要
【目的】选择性催化还原(selective catalytic reduction,SCR)脱硝技术广泛应用于火力发电厂循环流化床锅炉,在实际运行过程中,氨的使用量过大,氨逃逸率高,导致空气预热器腐蚀、堵塞、压差大。为解决这些问题,对某发电厂350 MW超临界循环流化床锅炉的脱硝系统进行了改造和优化。【方法】在该超临界循环流化床锅炉的二级省煤器、一级省煤器之间添加一层SCR催化剂,在旋风分离器烟气出口处增加尿素喷枪;通过分层给空气、优化风量,实现低氮燃烧;通过分片区控制喷氨系统运行做到精准喷氨,并定期维护设备。【结果】经过改造和优化,在实现超低排放的基础上,喷氨系统投入温度降低,锅炉在30%负荷下能连续稳定运行,尿素使用量减少,氨逃逸率降低,空气预热器蓄热元件与电除尘布袋基本没有积灰,二者的压差小于设计值。【结论】通过对脱硝系统改造并进行运行优化,可以有效提高脱硝系统运行效率,降低氨逃逸率。
[Objectives]Selective catalytic reduction(SCR)denitrification technology is widely used in circulating fluidized bed boilers in thermal power plants.During actual operation,the amount of ammonia used is too high and the ammonia escape rate is high,resulting in air preheater corrosion,blockage,and high differential pressure.In order to solve these problems,the denitration system of a 350 MW supercritical circulating fluidized bed boiler in a power plant was reformed and optimized.[Methods]A layer of SCR catalyst was added between the secondary economizer and the primary economizer of the supercritical circulating fluidized bed boiler,and a urea lance was added at the flue gas outlet of the cyclone separator.The low-NO_(x) combustion was achieved by grading the air supply and optimizing the air volume.The ammonia injection system was controlled in separate areas to achieve precise ammonia injection,and the equipment was regularly maintained.[Results]After modification and optimization,on the basis of achieving ultra-low emissions,the input temperature of the ammonia injection system is reduced,the boiler can run continuously and stably under 30%load.Moreover,the use of urea is reduced,the ammonia escape rate is decreased,and there is basically no ash deposit on the heat storage element of air preheater and the bag of electrostatic precipitator.The pressure difference between them is less than the design value.[Conclusions]The operation efficiency of the denitration system can be improved effectively and the ammonia escape rate can be reduced by reforming and optimizing the denitration system.
作者
李建军
尚曼霞
董海龙
李冰铭
黄中
LI Jianjun;SHANG Manxia;DONG Hailong;LI Bingming;HUANG Zhong(Guangxi Hualei New Material Co.,Ltd.Power Plant,Baise 531499,Guangxi Zhuang Autonomous Region,China;Key Laboratory for Thermal Science and Power Engineering of Ministry of Education(Tsinghua University),Haidian District,Beijing 100084,China)
出处
《发电技术》
2025年第5期1014-1021,共8页
Power Generation Technology
基金
国家重点研发计划项目(2022YFB4100303)。
