Ag/Al2O3催化二甲醚选择性还原NOx的试验研究

为了拓展二甲醚（DME）在低温条件下选择性催化还原NOx的效果，采用浸渍法制备了Ag/γ-Al₂O₃催化剂，试验研究了反应温度、Ag/γ-Al₂O₃质量分数、氧含量、NOx源、DME/NO摩尔比对NOx转化率的影响.结果表明，Ag/γ-Al₂O₃催化剂在低温条件下具有良好的脱氮性能，在200 °C时就显示较高的活性，随着温度的升高，NOx转化率先增大后减小；Ag/γ-Al₂O₃的催化活性随氧含量的增加先增大后减小，氧含量约为8%时催化效果最佳；最佳Ag质量分数约为3%；DME/NO最佳摩尔比为2；催化活性基本不受NOx源的影响.

Experimental Study of Dimethyl-Ether Selective Catalytic Reduction NO_x over Ag/Al_2O_3 Catalyst

In order to expand the low temperature range of selective catalytic reduction (SCR) NOx by dimethyl-ether (DME), NOx conversion to N2 over Ag/γ-Al₂O₃catalyst was experimentally studied. The catalyst was prepared by using impregnation method, and the influence of the reaction temperature, the content of Ag, the oxygen concentration, NOx source and the molar ratio of DME/NO were investigated respectively. The results show that Ag/γ-Al₂O₃displays favorable activity even at 200　°C and the NOx conversion ratio increases at the beginning and then decreases as the temperature increasing. The NOx conversion ratio climbs up and then declines as the oxygen concentration increasing, and the best catalyst activity appears when oxygen content is about 8%. The Ag loading of about 3% can get best catalyst activity, and the DME/NO molar ratio for the highest NOx conversion is 2. The influence of NOx source on NOx conversion is very small.