高水分煤在流化床中燃烧时NO_x的排放特性

NOx Emissions Characteristics During the Combustion of High moisture Coals in Fluidized Bed Combustors

通过数值计算，研究了高水分煤在流化床中燃烧时ＮＯ的排放特性及其形成的主要影响因素。结果表明煤中的水分、床内的ＣＯ浓度和空－燃比等都对于ＮＯ转换率有较大影响。随着床内水分的增加，使得ＣＯ的浓度增加，导致ＮＯ转换率下降。当空－燃比下降时，ＮＯ转换率也减少。对于ＮＯ生成和还原反应的累积反应速率表明，影响ＮＯ排放的主要因素是床内ＣＯ的浓度及焦炭的含量，而Ｈ２对ＮＯ的反应影响不大。

Through numerical calculations the NO emissions characteristics of high moisture coals during their combustion in fluidized bed combustors (FBC) have been studied with main influencing factors being identified. The study results show that the water content in coal, CO concentration and air fuel ratio in the bed all have a significant effect on the NO conversion rate. With an increase in moisture content in the bed there emerged an increase in CO concentration, leading to a reduction in NO conversion rate. With a reduction in the air fuel ratio the NO conversion rate will also decrease. Through the observation of accumulated reaction rates for NO formation and reduction it can be shown that the main factor influencing the NO emissions is the CO concentration and char content in the bed, while H 2 concentration has little effect on NO reaction.