煤粉工业锅炉的选择性非催化还原脱硝性能试验改进

Experiment study and optimization reformation of the SNCR of the pulverized coal industrial fired boiler

采用选择性非催化还原(SNCR)脱硝须克服脱硝效率偏低和氨逃逸严重等现象,对其进行试验改进可提升多种类型锅炉的脱硝性能。基于煤粉工业锅炉SNCR试验系统,通过试验测量2种炉膛结构、不同容量的煤粉工业锅炉炉膛温度分布,从喷枪支数、温度和SNCR等方面阐述对脱硝性能的影响,对4个供热站的15台锅炉进行SNCR优化改造,增加喷枪开孔和电磁流量计并改造SNCR系统管路,进而对SNCR优化改造效果进行评估,从而研究单喷枪和多喷枪组合对选择性非催化还原(SNCR)脱硝性能的影响。结果发现:喷枪组合的脱硝效率一般优于单喷枪,主要取决于炉膛内温度分布,即需获得最佳脱硝反应温度和氨氮物质的量比及找到锅炉SNCR的最佳喷枪位置;当炉膛截面平均温度为800~900℃、氨氮比为1.5~2.0时,SNCR可达到较好的脱硝效率且氨逃逸较低;对供热站改造前后的脱硝反应剂用量进行分析,发现改造后的尿素用量比未改造前总体降低23.2%,液氧用量总体降低75.3%,即改造后的尿素用量和液氧用量均显著降低,说明供热站SNCR改造能够大幅降低煤粉锅炉的运行成本。

The use of the Selective Non Catalytic Reduction(SNCR)need to overcome the problems of the low denitrification efficiency and serious ammonia escape.The optimization experiment was carried out to improve the denitrification performance of types of boiler furnace.Based on coal powder industrial boiler SNCR test system,by experimentally measuring the temperature distribution of two types of furnace structures and different capacities of coal powder industrial boilers,the influence of the number of spray guns and temperature on SNCR denitrification performance is explained,the SNCR of the 15 boilers of four heating stations were optimizing modified.The holes of the spray gun and the electromagnetic flowmeters were added and the pipelines were reformed for the SNCR system.The effectiveness of SNCR optimization and transformation were further evaluated.The results shown that the denitrification efficiency with two spray guns is higher than that with one spray gun,which is mainly depended on the temperature distribution.The optimal denitrification reaction temperature and ammonia nitrogen substance ratio should be obtained,and the optimal spray gun position for boiler SNCR should be found.When the average temperature of the furnace cross-section is 800~900℃and the ammonia nitrogen ratio is 1.5~2.0,SNCR can achieve good denitrification efficiency and low ammonia escape;the dosage of denitrification reagents before and after the renovation of the heating station were analyzed,the dosage of urea is decreased by 23.2%compared with that before optimization reformation and the dosage of liquid oxygen is reduced by 75.3%.The urea and liquid oxygen consumption after the renovation were significantly reduced,which indicates that the SNCR renovation of the heating station can significantly reduce the operating cost of coal powder boilers.