440t/h循环流化床锅炉NO_(x)超低排放研究

Study on Ultra-Low NO_(x)Emission of 440 t/h Circulating Fluidized Bed Boiler

辽宁省某热电厂的440 t/h循环流化床锅炉采用选择性非催化还原(SNCR)的脱硝工艺,以尿素为还原剂,SNCR系统投运后,氮氧化物(NO_(x))排放设计值不大于200 mg/Nm^(3)。为保护环境,降低NO_(x)排放量,该热电厂进行机组烟气(尾气)再循环改造、二次风深度分级改造、喷射系统改造和锅炉燃烧调整,成功地将NO_(x)排放量由200 mg/Nm^(3)降到50 mg/Nm^(3)以内,实现锅炉低负荷运行条件下NO_(x)的超低稳定排放,达到相关排放标准要求。

The 440 t/h circulating fluidized bed boiler of a thermal power plant in Liaoning Province adopts a selective non-catalytic reduction(SNCR)denitrification process,using urea as the reducing agent,after the SNCR system is put into operation,the designed value of nitrogen oxide(NO_(x))emissions is not more than 200 mg/Nm^(3).In order to protect the environment and reduce NO_(x)emissions,the thermal power plant has carried out unit flue gas(tail gas)recirculation renovation,secondary air deep classification renovation,injection system renovation,and boiler combustion adjustment,the NO_(x)emissions have been successfully reduced from 200 mg/Nm^(3) to within 50 mg/Nm^(3),achieving ultra-low and stable NO_(x)emissions under low load operating conditions of the boiler,and meeting the requirements of relevant emission standards.