La_(0.8)K_(0.2)MnO_3催化去除NO_x和碳烟反应的研究

Studies on the Redox Between NO_x and Soot over La_(0.8)K_(0.2)MnO_3

利用程序升温反应技术(TPR)详细考察了在La0.8K0.2MnO3催化作用下,反应气体流量、反应气中碳烟质量分数和氧体积分数变化对NOx和碳烟氧化还原反应的影响.研究结果表明,反应气体流量越低、碳烟质量分数越高,越有利于反应进行.当流量由100 mL/min减小至40 mL/min时,碳烟的起燃温度和最大燃烧温度会降低大约50℃,NOx转化为N2的最大效率则从9.7%升至19.1%;碳烟质量分数的改变对碳烟的燃烧温度基本没有影响,但NOx转化为N2的效率随着碳烟质量分数的增加而显著增加,碳烟质量分数由3%增至18%时,NOx转化为N2的最大效率从8.4%升至27.3%;氧体积分数改变对催化反应有两方面影响,氧体积分数增加能促进碳烟的燃烧,但对NOx还原有一定程度的抑制作用,当氧体积分数由2%变为5%时,碳烟的起燃温度和最大燃烧温度分别从330℃和405℃降低了30℃,NOx转化为N2的最大效率从14.5%降至11.2%.

The effects of reaction conditions, such as flow rate of reaction gases, soot content and oxygen concentration, on the redox between soot and NO, were investigated over La0.8K0.2MnO3 catalyst. The results indicate that less flow rate and higher soot content are favorable for the reaction. When the flow rate is changed from 100 mL/min to 40 mL/min, the ignition temperature and maximum combustion temperature decrease by ca 50℃, while the maximum conversion of NO, to N2 increases from 9.4% to 19. 1%. When soot content is increased from 3% to 18%, the combustion temperature remains unchanged, whereas the maximum conversion of NO, to N2 increases from 8.4% to 27.3%. As to different O2 content, it was found that oxygen benefits soot combustion, but inhibits NO, reduction to some extent. Both ignition temperature and maximum combustion temperature decrease by ca 30℃ from 330℃ and 405℃, and the maximum conversion of NO, to N2 decreases from 14.5% to 11.2% when O2 content is changed from 2% to 5%.