含氨煤气再燃脱硝反应的化学动力学模拟

Kinetic Modeling of the NO_x Reduction by Reburning With Ammonia-containing Coal Gas

煤气再燃有望成为一种有效的低污染燃烧方式得到广泛的使用。该文利用化学动力学模型对2种典型含氨煤气的脱硝反应特性进行了模拟研究。计算结果发现,再燃停留时间的延长可以显著提高再燃脱硝的效果,再燃停留时间应该大于1s才能取得较好的脱硝效果。同时,再燃温度越高,反应越迅速,脱硝效果越好。再燃区过量空气系数的降低对脱硝也有好处。煤气中的氨成分对煤气脱硝有一定的促进效果,而且随着反应温度的降低和再燃比例的增加,促进效果增强。含烃煤气与非烃煤气的再燃特性有很显著的差异,进行低NOx燃烧方式设计的时候应特别注意。

Coal gas reburning is an effective low-emission combustion technology with a promising future in China. The reduction of NO by two typical ammonia-containing coal gases has been modeled using a detailed chemical kinetic mechanism. These calculations indicate that increasing residence time in the reburn zone （t2） improves the NO reduction significantly and t2〉ls is required to achieve a sufficient NO reduction. Meanwhile, reactions speed up at higher rebuming temperature and result in a higher NO reduction at a given residence time. The decreasing excess air ratio in the reburn zone also helps the deNOx reaction. The ammonia component in the coal gas has a certain promotion effect on NO reduction, and the promotion effect increases with decreasing reburning temperature and increasing reburn fuel ratio. Hydrocarbon and non-hydrocarbon coal gases have different reburning characteristics, and should be taken into account during low NOx combustion design.