煤焦再燃过程中催化剂对NO还原的影响

The Effect of Catalysts on NO Reduction during the Reburning of Coal Chars

以小龙潭褐煤、富拉尔基褐煤和大同烟煤等制成的三种煤焦为再燃燃料 ,研究了它们在再燃区内对NO的还原过程 ,分析了煤灰中金属氧化物对NO还原的影响。为了研究碱金属氧化物对NO还原的催化作用 ,本文特别研究了烟煤焦经过浸泡催化剂处理后对NO的再燃过程及对NO还原率的影响。实验是在NO初始浓度为 10 0 0× 10 -6,反应温度分别为 90 0℃和 110 0℃条件下完成的。实验结果表明 ,煤灰中金属氧化物在再燃区中对NO还原有很强的催化作用 ,原来对NO还原效果很差的烟煤焦 ,添加廉价催化剂后对NO的异相还原有很大的影响 ,在合适的反应温度和化学当量比(SR)条件下 ,煤焦中的催化剂能降低NO还原反应的活化能 ,加快NO还原反应进行的速度 ,从而提高NO的还原率。

With three kinds of coal char made from Xianglongtan lignite, Fulaerki lignite and Datong bituminous coal serving as reburning coals a study was conducted of the effect of these coal chars on the process of NO reduction in the reburning zone. Also analyzed was the effect of metallic oxides in the coal ash on the NO reduction. To study the catalytic action of alkali metallic oxides on the NO reduction, the authors have specially investigated the effect of bituminous coal char after its being subjected to an impregnated catalyst treatment on the NO reburning process and NO reduction rate. The test was completed at an initial concentration of NO at 1 000×10 6 and under reaction temperatures of 900 ℃ and 1 100 ℃ respectively. The test results indicate that the metallic oxides in the coal ash have a very strong catalytic action on NO in the reburning zone. The bituminous coal char originally believed to have a very poor effect on NO reduction can exercise a great influence on heterogeneous reduction of NO after a cheap catalyst being added to the above mentioned coal char. Under the condition of an appropriate reaction temperature and stoichiometric ratio (SR) the catalyst in the coal char can reduce the activation energy of NO reduction reaction and expedite the speed of that reaction, thus quickening the NO reduction speed.