影响75t/h中温分离CFB锅炉SNCR脱硝效果的因素分析

Factor Analysis on Effects of 75 t/h Medium Temperature Separated CFB Boiler on SNCR Denitrification

以2台燃烧福建无烟煤的采用中温分离技术的75t/hCFB锅炉为研究对象,在CFB锅炉炉膛内而不是在旋风分离器入口烟道喷入氨水进行SNCR反应,通过工业热态试验,得到炉膛出口温度等运行参数对SNCR脱硝效果的影响趋势:(1)NO_x排放浓度随着炉膛出口温度提高而增加且增速逐渐加大,随着氨氮摩尔比NSR增加而下降且降速逐渐减小,随着喷枪位置提高先下降后增加,随着喷枪数量增加先下降后增加;(2)SNCR脱硝效率随着炉膛出口温度提高先增加后降低,随着NSR增加而增加且增速逐渐减小,随着喷枪位置提高先增加后下降,随着喷枪数量增加而先增加后下降;(3)氨逃逸质量分数随着炉膛出口温度提高而降低且降速逐渐减小,随着NSR增加而增加且增速逐渐加大,随着喷枪位置提高而增加。试验表明,存在最佳的温度反应区间、喷枪位置和数量使SNCR脱硝效率最大,为SNCR优化运行提供指导依据。

This study takes two 75t/hCFB boilers as the research object which burns the Fujian anthracite coal and adopts the medium temperature separation technology. Through the industrial thermal test, SNCR reaction was carried out by injecting ammonia into the furnace of CFB boiler other than in the inlet flue of the cyclone separator, the trend of SNCR denitrification effect of the furnace outlet temperature and other operating parameters are made out ： （1）The concentration of NO~ emission increases with the increase of furnace outlet temperature and the growth rate increases gradually, it decreases with the increase of theam- monia nitrogen molar ratio NSR and the decraese rate will slow down gradually , and it decreases at first and then increases with the increase of the spray gun position, and it increases at first and then decraeses then with the increase of the number of the spray guns~ （2） The SNCR denitrification effect will increases at first and then decreases with the increase of the furnace outlet temperature, it increases with the in- crease of the NSR and the growth rate slows down gradually, it and it increases at first and then decreases with the increase of the spray gun position, and it increases at first and then decraeses then with the in- crease of the number of the spray guns; （3） Ammonia escape mass fraction decreases with the increase of furnace outlet temperature and the decrease rate slows down gradually, it increases with the increase of the NSR and the growth rate increases gradually, it increases with the increase of the spray gun position. The study shows that , there exists the best temperature range, the best position of the spary gun and the best quantity to make the largest SNCR denitration efficiency, which will provide the guidance for the SNCR op- timal operation.