尿素法SNCR对大型电站煤粉锅炉运行影响的工业试验

在660MW超临界W火焰锅炉上开展了工业试验，研究了尿素法选择性非催化还原脱硝（SNCR）投运对锅炉热效率、NOx排放、SCR入口烟道截面NOx分布及炉内烟气温度的影响。结果表明：SNCR系统喷入炉内的水汽化吸热是导致锅炉热效率降低的主要原因，喷入炉内水流量增加1.0t/h，锅炉热效率降低约0.05个百分点；稀释水流量影响尿素溶液在炉内的雾化和分配效果，在尿素用量相同条件下适当增加稀释水流量，SNCR脱硝效率会显著提高；相对于试验负荷下约2400t/h的烟气流量，SNCR喷入炉内的尿素溶液流量相对较少（占0.2%～0.5%），因此，对炉内烟气温度影响并不明显。在一定范围内调整稀释水和尿素溶液流量对SCR入口烟道截面NOx分布的影响并不明显，但是过低的稀释水流量会影响炉内尿素混合效果，进而影响SCR入口NOx浓度在烟道截面深度方向上分布的均匀性。

Industrial experiment on the effect of SNCR using urea as the reducing agent on the operation of large capacity power station pulverized coal boiler

Industrial experiments were carried out on a 660MW super-critical down-fired boiler, and the effects of SNCR on thermal efficiency, NO _x emission, NO _{xdistribution at SCR inlet, and flue gas temperature in the boiler furnace were analyzed in detail. The results showed that the evaporation and heat absorption of the water injected into the furnace by SNCR system was the main reason for the decrease of boiler thermal efficiency. when the water flow rate increased by 1.0t/h, the boiler thermal efficiency decreases by about 0.05%. The dilution water flow rate had a significant effect on the atomization and distribution of urea solution in the furnace. Under the condition of the same amount of urea, the denitration efficiency of SNCR could be significantly improved by appropriately increasing the dilution water flow. Compared with the flue gas flow (about 2400t/h) under the test load, the flow of urea solution injected into the furnace was relatively small, accounting for about 0.2%—0.5%. Therefore, it had no obvious effect on the flue gas temperature in the furnace.Adjusting the flow rate of dilute water and urea solution within a certain range had no obvious influence on NO x distribution in the section of SCR inlet flue, but too low dilution water flow rate would affect the mixing effect of urea in the furnace, and then affected the distribution of NO xconcentration in the section of SCR inlet flue.}