燃煤电站锅炉烟气脱硝改造及运行分析

Retrofit and Operation Analysis of Coal-fired Flue Gas Denitration in Power Plant

以国内某电厂7台煤粉锅炉实现超低排放为指标进行燃煤电站烟气脱硝改造,采用低NO_x燃烧技术和炉后选择性催化还原技术相结合的工艺,对煤粉锅炉燃烧方式、SCR脱硝系统、引风机等进行设计改造,研究了空气过量系数、反应器温度、氨氮摩尔比等对脱硝效率的影响,并对改造后系统进行调试。结果表明,温度控制在360℃附近,过量空气系数在0.9～1.0之间,氨氮摩尔比为1.2时,SCR脱硝效率达到90%以上,烟气出口NO_x质量浓度在45 mg/Nm^3以下,烟气出口温度为250～280℃之间,符合环保部门的排放指标。

To realize ultra-low emission,coal-fired flue gas denitration of seven power plant was reformed.The mixture of low NO combustion technology and post-furnace selective catalytic reduction technology was utilized for the denitration system,in which the combustor of pulverized coal boiler,SCR denitration system,and induced fan were designed and modified accordingly.Moreover,the effect of excess air coefficient,the reactor temperature and ammonia-nitrogen mole ratio on denitration efficiency was investigated.The experimental results showed that when the temperature was controlled at about 360益,the excess air coefficient was between 0.9-1.0,the ammonia-nitrogen ratio was about 1.2,the comprehensive denitration efficiency of the SCR system of power plant could reach more than 90%,and the NO concentration in flue gas outlet was below 45 mg/Nm3 and the outlet temperature of flue gas of about 250-280益,in line with environmental protection department emission targets.