330 MW机组SCR脱硝系统灵活性优化改造技术研究

Research on Flexibility Optimal Transformation Technology of SCR System of 350MW Unit

以某330 MW机组SCR脱硝系统为研究对象,为了适应机组深度灵活性调峰,开展SCR脱硝系统优化改造技术研究。结合煤中的硫分和水分,机组负荷降低至30%THA工况时,为了满足脱硝系统能够正常运行,脱硝入口烟气温度需提高18℃,从技术安全性、可靠性和经济性等方面分析比较省煤器烟气旁路、省煤器分级、省煤器给水旁路、省煤器热水再循环和增设零号高加等提升脱硝系统低负荷时烟气温度技术,确定省煤器水旁路为最佳改造方案,为同类型机组脱硝系统改造提供参考依据。

Taking SCR Denitration system of a 330MW Unit as an object of study,in order to adapt to the depth flexibility peak shaving of the unit,the optimization modification technology of the SCR denitrification system is carried out.In order to meet the normal operation of the denitrification system,the flue gas temperature of the denitration inlet should be increased by 18℃when the load of the unit is reduced to 30%THA condition combined with the sulfur and water content of the coal,the economizer flue gas bypass,economizer classification,economizer feed water bypass,economizer hot water recirculation and the addition of zero high plus lift denitrification system with low load flue gas temperature technology are analyzed and compared in terms of technical safety,reliability and economy.The water by-pass of economizer is determined as the best retrofit scheme,and the reference basis is provided for the revamping of denitrification system of the same type of unit.