Mo掺入CeO_2/Al_2O_3选择性催化还原NO动力学研究  

Kinetics study of molybdenum additives on catalytic performance of CeO_2/Al_2O_3 for selective catalytic reduction of NO

作　　者：严巍[1] 沈岳松[1] 金奇杰[1] 刘海沛[1] 祝社民[1] 沈树宝[2] 

机构地区：[1]南京工业大学材料科学与工程学院江苏先进无机功能复合材料协同创新中心,南京210009 [2]南京工业大学生物与制药工程学院,南京211816

出　　处：《环境工程学报》2017年第6期3594-3600,共7页Chinese Journal of Environmental Engineering

基　　金：江苏省社会发展科技支撑计划项目(BE2013718);国家自然科学基金资助项目(51272105)

摘　　要：采用共混法制备不同系列Mo掺入催化剂(CeMo_xO_y/Al_2O_3),研究了Mo掺入对CeO_2/Al_2O_3选择性催化还原NO活性的优化,考察了内外扩散对脱硝性能的影响,并计算得出反应活化能,从动力学角度考察了Mo掺入对脱硝活性反应速率的影响。结果表明,Al/Ce/Mo元素摩尔比为5∶1∶0.15,空速为7 200 h-1,煅烧温度为550℃时,催化剂在250~425℃内脱出NO_x效率均大于90%;催化剂平均粒径小于40目时,空速大于105h-1时,内外扩散的影响可以忽略不计,CeMo_xO_y/Al_2O_3催化反应为一级反应,其中NH_3和O_2反应级数近似为0级。Ce Mo0.15Oy/Al_2O_3活化能为36.57 k J·mol-1,Mo的添加有效的减小了催化剂的表观反应活化能,增加了反应速率,提高了催化活性。A series of CeMoxOy/Al2O3 catalysts were prepared by an extrusion method for the selective catalytic reduction of NOx.Promotional effects of molybdenum additives on catalytic performances and the effects on the reaction of internal and external diffusion were studied;the reaction activation energy was calculated.The promotional effects of molybdenum additives on the reaction rate of CeO2/Al2O3 for the selective catalytic reduction of NO were investigated.Results show that the catalyst with an Al/Ce/Mo molar ratio of 5：1：0.15, calcinated at 550℃, exhibits the highest catalytic activity （above 90%） in the active temperature window of 250 to 425℃ under the gas hourly space velocity （GHSV） of 7 200 h-1.When the particle size is less than 40 mesh and the space velocity is more than 105 h-1, the effects of internal and external diffusion could be neglected.The selective catalytic reduction （SCR） reaction on CeMo0.15Oy/Al2O3 was a first-order reaction, and the apparent reaction order was over the range of conditions, approximately 0 for NH3 and O2.The reaction activation energy of CeMo0.15Oy/Al2O3 was 36.57 kJ·mol-1, Mo additives reduced the activation energy of the catalyst reaction, which increased the rate of reaction and thereby improved the catalytic activity.

关 键 词：CeMoxOy/Al2O3催化剂 LSCR L动力学 L反应活化能 

分 类 号：X701.3[环境科学与工程—环境工程]