钒酸盐对柴油机排气中碳烟氧化的催化性能

制备并表征了KVO3、K4V2O7和熔盐KVO3 KCl、K4V2O7 KCl催化剂.用固定床反应器通过程序升温氧化法(TPO)研究了催化剂在紧密接触和松散接触条件下对柴油发动机排气微粒中碳烟氧化的催化活性,考察了催化剂的热稳定性,并用泡沫陶瓷作为过滤材料研究了催化剂的性能.结果表明:钒酸盐催化剂KVO3、K4V2O7、KVO3 KCl和K4V2O7 KCl对柴油机排气中碳烟微粒的燃烧具有较高的催化活性和热稳定性.熔盐催化剂KVO3 KCl和K4V2O7 KCl的流动性增加了与碳烟的接触,使其具有较高的催化能力.γ-Al2O3能防止负载于其上的催化剂因吸潮而产生的团聚,但是其稀释作用使催化剂的性能降低.与碳烟的接触方式对催化剂的性能有很大影响,紧密接触方式使催化剂与碳烟颗粒混合均匀,增加了催化剂与碳烟颗粒的接触机会.

Study on catalytic performance of vanadate for the oxidation of soot from diesel exhaust

The catalysts of KVO_3, K_4V_2O_7, KVO_3+KCl and K_4V_2O_7+KCl were prepared andcharacterized. Their catalytic activity was investigated by a fixed-bed reactor for the soot obtainedfrom the diesel emissions under the tight and loose contact mode. The thermal stability of catalystsand catalytic performance of catalysts supported on foam ceramic were also studied. The results showthat the catalysts of KVO_3. K_4V_2O_7, KVO_3+KCl and K_4V_2O_7+KCl have high thermal stability andcatalytic activity for the soot. The molten salt catalysts of KVO_3+KCl and K_4V_2O_7+KCl have higheractivity than that of KVO_3, K_4V_2O_7 because their mobility increases the contact chance of catalystsand soot. The contact mode between catalyst and soot is an important factor that influences thecatalytic performance of catalysts. The catalyst and soot are mixed evenly under the mode of tightcontact, which increases the contact chance of catalyst and soot.