循环流化床燃烧在高过剩空气下的NOx排放

提出了借助循环流化床在高过剩空气系数下燃烧的技术提供高温空气的新构思。搭建了循环流化床燃烧热态试验台,完成了循环流化床燃烧在高过剩空气系数下的NOx排放特性试验,结果表明:循环流化床在高过剩空气系数下燃烧温度分布均匀,燃烧稳定性好;过剩空气系数增大,氮氧化物排放增加;提升管二次风高度的增加和还原区系数的减小有利于控制氮氧化物的排放水平和减少煤中的N向NOx的转化比。在过剩空气系数为1.6、还原区系数为0.72和二次风高度为1 500 mm时,循环流化床NOx排放为339 mg/m3,煤中的N向NOx转化比为21%。循环流化床高温空气NOx的浓度对燃料高温燃烧NOx排放的影响需要进一步研究。

NOx emission of circulating fluidized bed coal combustion at high excess air ratio

A new concept of achieving high temperature air by circulating fluidized bed combustion at high excess air ratio was proposed.A test rig was built and experiments were carried out.The results show that combustion in the circulating fluidized bed is stable,and the temperature profile is uniform.NOx emission and the conversion rate of coal-N to NOx are proportional to the excess air ratio,and decrease with both the increasing of secondary air height and the decreasing of reducing zone factor.With the excess air ratio of 1.6,the reducing zone factor of 0.72,and the secondary air port at the height of 1 500 mm,the NOx emission is 339 mg/m3 and the conversion rate of coal-N to NOx is 21%.The effect of NOx concentration on the high temperature air combustion needs further investigation.