SNCR-SCR耦合脱硝中还原剂均布性的研究

Uniform distribution characteristics of reducing agent on hybrid SNCR-SCR process

为了提高选择性非催化还原-选择性催化还原(SNCR-SCR)耦合脱硝中还原剂浓度在尾部烟道内分布的均匀性,以某60 MW四角切圆煤粉炉为原型,按1∶10的比例搭建混合SNCR-SCR脱硝系统冷态实验台.设计了2种补氨方案,分析不同工况下还原剂的分布趋势和标准偏差.结果表明,布置补氨喷枪后,SCR入口还原剂的均布性明显得到了改善,浓度分布的标准偏差系数从62%降低到了43%.根据冷态实验结果,将优化后的补氨方案应用于现场锅炉,SNCR和SCR脱硝过程的效率分别达到了43%和66%,联合脱硝效率提高了54%,氨逃逸的体积分数小于5×10-6.

A cold test bench was built based on a commercial 60 MW tangentially coal-fired utility boiler with a scale of 1∶10in order to improve the uniform distribution characteristics of reducing agent in the tail flue on hybrid selective non-catalytic reducing and selective catalytic reducing（SNCR-SCR）process.Two ammonia supplementary programs were designed.Measurements were conducted to analyze the trends and standard deviation of concentration distribution of reducing agent in different cases.Results showed the standard deviation factor decreased from 62%to 43% which indicated the uniformity of reducing agent was obviously improved.After applying optimized ammonia injection procedure ever gotten,the De-NOXefficiency of SNCR and SCR process achieved 43% and 66%,respectively.The total efficiency of combined De-NOXprocess increased by 54% and the ammonia slip was no more than 5×10^-6.