SCR脱硝全区域NH_(3)/NO_(x)等摩尔比优化研究

Study on optimization of NH;/NO;molar ratio in the whole area of SCR denitrification system

为指导喷氨优化调整,对某煤粉炉选择性催化还原(selective catalytic reduction,SCR)脱硝装置开展网格法现场测试。以现场实测的非均匀NO_(x)质量浓度场和运行参数作为计算流体力学(CFD)模拟的输入条件,将计算的出口参数与实测值进行比较,发现计算与实测均表明A,B侧脱硝反应器出口NO_(x)分布均匀性较差,局部氨逃逸较高。分析不同喷氨策略下出口NO_(x)质量浓度分布,获得最优喷氨策略,并在不停炉情况下开展喷氨调门优化。优化后脱硝出口氨逃逸降低到合理水平,空气预热器阻力降低到正常范围,机组运行的安全性与经济性得到了提高。

In order to instruct the optimization and adjustment of ammonia injection,the grid-method field test was carried out for SCR denitrification device of a pulverized coal boiler.The measured non-uniform NO_(x) mass concentration field and operation parameters were taken as the input conditions of CFD simulation,and the calculated outlet parameters were compared with the measured values.It was found that the poor uniformity of NO_(x) distribution at the outlet of denitrification reactor on side A and side B,and the local ammonia escape was obvious.The distribution of NOxmass concentration at outlet under different ammonia injection strategies was compared,and the optimal ammonia injection strategy was finally obtained.The ammonia injection valve optimization was carried out without boiler shutdown.After optimization,the ammonia escape at the denitration outlet was reduced to a reasonable level,and the resistance of air preheater was reduced to the normal range,which improved the operation safety and economy of the unit.