混煤燃烧过程中的交互作用:过量空气系数对混煤燃尽特性的影响

在沉降炉上对无烟煤、贫煤、烟煤、褐煤以及不同配比(25%、50%、75%)混煤开展了过量空气系数对混煤燃尽特性影响的实验研究。结果表明,混煤燃烧中挥发分高的煤对挥发分低的煤存在促进和抑制2种交互作用。"炉外"掺烧方式下,低挥发分煤与高挥发分煤掺混时,抢风抑制作用表现明显;尤其是掺烧75%高挥发分煤时,抢风抑制作用最为显著;提高过量空气系数可以改善贫氧气氛,减弱混煤燃烧中的抢风抑制作用,提高混煤燃尽率。"炉内"掺烧方式下,过量空气系数的增加,交互作用减弱,各单煤的燃烧独立性增强,混煤燃尽率逐渐接近计算线性燃尽率。

Interaction of blended-coal combustion process:Influence of excess air coefficient on burnout characteristics

The experiment of the influence of excess air coefficient on the burnout characteristics are performed under four coals and their blended coals (0％ 、25％ 、50％ 、75％ 、100％) The resuhs show that the combustion of blended coal is impacted by two opposite effects:the promote function and the restrain function.Under the out-furnace coal blending method,the interaction of blended coal is obvious when low-volatile coal is blended with high-volatile coals (especially,under the blending ratio of 75％).Enhancing the excess air coefficient can weaken the restrain function.Under the in-furnace coal blending method,when low-volatile coal is blended with high-volatile coals,as increasing the excess air coefficient,the restrain function is also lower,and the combustion independence of individual coals gradually increases,and the burnout of blended coal approaches the linear value.