分区控氨技术在炼油厂选择性催化还原烟气脱硝中的应用

APPLICATION OF PARTITION AMMONIA INJECTION IN SCR DENO_x OF REFINERY FLUE GAS

针对选择性催化还原(SCR)脱硝反应器同截面温度分布不均,导致NO_x浓度分布不均,严重影响脱硝效果,采用传统的均匀喷氨方式无法有效解决脱硝率低、局部氨逃逸的问题,以炼油厂自备锅炉SCR脱硝装置为研究对象,在SCR脱硝反应器入口烟气NO_x浓度分布不均的情况下,采用分区喷氨的控氨方式,提高脱硝率的同时改善反应器出口截面NO_x浓度分布的均匀性,有效控制了氨逃逸。分区喷氨与均匀喷氨实验数据相比,分区喷氨后脱硝率提高11.5百分点,氨耗量减少5kg/h,氨逃逸浓度降低77.5%。根据温度和浓度的关系估算,均匀喷氨时反应器入口同截面温度最高处和最低处温差应不超过30℃,否则需考虑分区喷氨方式。

Uneven distribution of temperature on the same cross-section of a SCR（selective catalytic reduction）de NOxreactor results in an uneven distribution of concentration of NOx,which seriously affects the SCR de NOx effect.Further,the traditional uniform ammonia injection method fails to effectively address the problem of low removal efficiency and local ammonia slip.In this work,the SCR deNOxdevice of refinery self-provided boilers was studied.The partition ammonia injection technique was employed to improve the NOxdistribution and diminish the ammonia escape in the case of non-uniform distribution of NOxconcentration in flue gases at the inlet of SCR deNOxreactor.Compared with the uniform ammonia injection method,the partition ammonia injection makes NOxremoval rate increase by 11.5percent points,while ammonia consumption is reduced by 5kg/h,and ammonia escape is declined by 77.5%.According to the estimation based on the relationship of temperature and concentration,if the different of highest and lowest temperature in the same cross-section of the reactor inlet is more than 30℃in the case of uniform ammonia injection,the partition ammonia injection method should be taken into consideration.