不同过量空气系数下层燃炉煤层NO_x析出特性研究

层燃炉燃煤特性和煤粉炉燃煤特性差异很大,为了了解过量空气系数对层燃炉NOx析出特性的影响,在层燃单元体炉上进行了不同过量空气系数下煤层表面NOx析出特性的对比实验。发现增大过量空气系数可强化燃烧,加快火焰锋面传递,提高燃烧温度;在挥发分析出阶段促进挥发分析出,增强还原性气氛,抑制NOx生成;在焦炭燃烧阶段提高氧浓度,促进NOx生成,降低了焦炭对NOx还原效果。

The Behavior of Nitrogen Oxides Emission of Stoker＇s Coal Bed with Different Excess Air Ratio

The combustion characteristic between large coal particle and pulverized coal is very different. To under- stand accurately the law of NOx emission, experiments for comparison of effects of NOx emission at the coal bed surface with different excess air ratio were carried out on the fixed-bed furnace. It has been found that large excess air ratio could en- hance the burning, accelerate the flame-front propagation, and improve the burning temperature. At the volatile-out stage, the large excess air ratio also could prompt the volatile out which could reduce the NOx, but at the char-burning stage, the large excess air ratio would improve the concentration of O2 , weakening the reduction property of the char on NOx.