采用微细煤焦再燃还原NO的反应机理

Mechanism of NO Reduction by Reburning Micronized Coal Char

以3种细度的混煤煤焦作为再燃燃料,用N2、O2、CO2和NO配制模拟烟气,在1200℃、1300℃和1400℃立管式携带炉中进行了再燃还原NO的实验研究,对其化学反应机理进行了分析。结果表明:微细化煤焦再燃还原NO的反应速率受扩散-反应动力学的联合控制。因此,提高再燃区温度水平、使用反应活性高的煤焦或提高再燃煤焦的细度,均能明显提高再燃还原NO的化学反应速率。

Experimental tests on NO reduction by reburning have been performed at 1200℃, 1300℃ and 1400℃, in an entraining tube furnace, using a mixture of coal char particles, with 3 different granularities, as the reburning fuel and a proper mixture of N2, 02, CO2, and NO as the simulated flue gas. The chemical reaction mechanism was therewith analyzed. Results indicate that the reducing reaction rate of NO depends upon the combined effect of diffusion and reaction kinetics. Therefore, the reducing reaction rate of NO can noticeably be increased by raising the temperature in the reburning zone and by using char of high reactivity or high granularity.