SCR脱硝系统中喷氨格栅改造研究

Study on the Modification of Ammonia Injection Grid in SCR Denitrification System

某公司#3炉脱硝喷氨浓度场分布不均,使得流场内分布的氨氮比(NH3/NOx)失衡,脱硝效率下降。现对#3炉脱硝喷氨格栅进行改造,以优化脱硝装置运行效果,增强喷氨均匀性。改造后A、B两侧SCR出口NOx相对标准偏差分别降至24.6%和29.1%,SCR出口NOx均匀增强。850 MW工况下氨逃逸浓度由10.75 ppm降至0.66 ppm,氨逃逸率下降95%。改造前空预器阻力平均在3.5 kPa,最高达到4 kPa;结合空预器蓄热元件改造空预器阻力稳定在1.35 kPa以下,较大程度减轻空预器的堵塞。

The uneven distribution of ammonia in the#3 furnace of a company results in the unbalanced ratio of NH3/NOx and decreased denitration efficiency.To optimize the operation effect of a denitration device and enhance the uniformity of ammonia,the ammonia injection grid is modified.The results show that after modification,the relative standard deviation of NOx at SCR outlet on both sides of A and B decreased to 24.6%and 29.1%respectively,and the NOx at SCR outlet increased uniformly.At 850MW,the ammonia escape concentration decreased from 10.75 ppm to 0.66 ppm,and the ammonia escape rate decreased by 95%.The average resistance of the unmodified air preheater is 3.5 kPa,and the maximum is 4 kPa.After the modification,the resistance of the air preheater was stabilized below 1.35 kPa,and the resistance of the air preheater was greatly reduced,which greatly reduced the blockage of the air preheater.