低负荷下给水温度对 SCR 及锅炉热效率的影响

摘要

当机组在较低负荷下运行,选择性催化还原(selective catalytic reduction,SCR)反应温度往往低于催化剂的最佳反应温度范围,使 SCR 脱硝效率低甚至退出运行,针对该问题,增加0号高压加热器(以下简称“高加”)是改善 SCR 脱硝系统运行特性的一项措施,但会影响锅炉热效率。为了研究增加0号高加对 SCR 脱硝效率和锅炉热效率的影响情况,以广东某电厂600 MW 机组为研究对象,首先对0号高加参数进行初步设计,然后对机组进行整体热力计算,并分析50%、60%和70%负荷下锅炉给水温度提高10℃、20℃以及30℃时对 SCR 脱硝效率和锅炉热效率的影响情况。%When the unit is running with lower load,reaction temperature of selective catalytic reduction (SCR)is lower than range of optimal reaction temperature of catalyst which may cause denitration efficiency of SCR low even make the unit de-commission.Aiming at the above problem,a measure of adding No.0 high pressure heater was adopted to improve running characteristic of SCR denitrtion system which might affect heating efficiency of the boiler however.In order to study influ-ence of adding No.0 high pressure heater on SCR denitration efficiency and heating efficiency of the boiler,one 600 MW unit of some Guangdong power plant was taken for a research object to firstly carry on an initial design on parameters of No.0 high pressure heater and then thermodynamic calculation on the unit.In addition,influence on SCR denitration effi-ciency and heating efficiency of the boiler by respectively raising feed water temperature of 10 ℃,20 ℃ and 30 ℃ with re-spective 50% load,60% load and 70% load was analyzed.