论文部分内容阅读
采用浸渍法制备了La_2O_3、Ce_2O_3和Co_2O_3等金属氧化物部分替代V_2O_5的氧化物-MoO_3-TiO_2型催化剂,并进行了理化性能和催化活性表征。结果表明:替代型催化剂的比表面积与钒型催化剂差别不大。在NH_3-SCR反应中,镧型和铈型催化剂不仪低温活性较高而且NO_x净化率在500℃时才开始衰减,具有最宽的活性温度窗口;钴型催化剂虽然低温活性最好,但其NO_x净化率在400℃即开始衰减,导致其活性温度窗口较窄,但还是比钒型催化剂宽。此外,反应温度是影响HC和CO排放变化的主要因素,而催化剂种类对其影响较小。1×10~5 h~(-1)以下时,不同空速对NO_x净化率影响较小;而空速达到3×10~5 h~(-1)时,NO_x净化率显著下降。
The oxide-MoO 3 -TiO 2 catalysts, which partially replace V 2 O 5 by metal oxides such as La 2 O 3, Ce 2 O 3 and Co 2 O 3, were prepared by impregnation method. Their physical and chemical properties and catalytic activity were also characterized. The results show that the specific surface area of the substitute catalyst is not significantly different from that of the vanadium catalyst. In NH_3-SCR reaction, lanthanum-type and cerium-type catalysts do not exhibit high activity at low temperature and the NO_x purification rate begins to decay at 500 ℃ with the widest active temperature window. Although the cobalt catalyst has the best low-temperature activity, The NO x purification rate begins to decrease at 400 ° C, resulting in a narrower active temperature window but still wider than the vanadium catalyst. In addition, the reaction temperature is the main factor that affects the change of HC and CO emissions, but the type of catalyst has little effect on it. When the space velocity reached to 3 × 10 ~ 5 h -1, the NO_x removal rate decreased significantly when the space velocity was below 1 × 10 ~ 5 h -1.