贯穿式喷枪在CFB锅炉SNCR脱硝上的应用研究

Application of Penetration Spray Guns in SNCR Denitration Process of CFB Boilers

因受到多种条件限制,某电厂2台UG-75/5.3-M3型CFB锅炉面临NO_(x)超低排放难题。经研究继续采用原SNCR脱硝工艺,仅使用贯穿式喷枪替换原有短喷枪。贯穿式喷枪独特的多喷嘴结构和双层错列的布置方式,使其拥有极大的覆盖面积,使烟气中的NO_(x)与尿素液能够在第一时间充分混合。脱硝系统改造后开启全部贯穿式喷枪时,脱硝效率达85%以上,NO_(x)排放满足超低标准。脱硝改造后氨氮物质的量比与改造前相比降低25%,尿素液用量明显减少,运行费用显著降低。通过两个供暖季的运行总结,贯穿式喷枪的使用对锅炉运行影响较小,炉膛负压与改造前相比未见明显变化,尾部受热面和空预器等状态变化均在可控范围内。冷却水和隔热耐磨层的使用对贯穿式喷枪起到了显著的保护作用,在运行两个供暖期后贯穿式喷枪整体状况良好。贯穿式喷枪独特的结构弥补了普通短喷枪的不足,显著提高了SNCR脱硝系统的脱硝效率,为企业脱硝提供了新的工艺选择。

Due to various constraints,two UG-75/5.3-M3 CFB boilers in a power plant faced the problem of ultra-low NO_(x) emission.After research,it was determined to continue using the original SNCR denitration process while replacing the existing short spray guns with penetration spray guns.Due to the unique multi-nozzle structure and double-layer staggered arrangement,the penetration spray gun has a large coverage area,so that the NO_(x) in flue gas can mix thoroughly with urea solution at the first chance.When all the penetration spray guns were opened after the modification of denitration system,the denitration efficiency reached more than 85%and the standard for ultra-low NO_(x) emission was met.After modification,the quantity ratio of ammonia nitrogen substance was reduced by 25%compared with that before modification,the consumption of urea solution was significantly reduced,and the operating cost was significantly reduced.Based on the operation summary of two heating seasons,it was concluded that the use of penetration spray gun has little influence on the operation of boilers,no significant changes were observed in the negative pressure of furnace compared with that before modification,and the state changes of rear heating surface and air preheater are within controllable range.The use of cooling water and thermal insulation wear layer has a significant protective effect on penetration spray guns,and the penetration spray guns were in good conditions after being operated for two heating seasons.The unique structure of penetration spray gun makes up for the shortage of ordinary short spray gun,significantly improves the denitration efficiency of SNCR denitration system,and provides a new process choice for the denitration of enterprises.