Cu/ZSM-5分子筛催化剂SCR催化性能

Performance of Selective Catalytic Reduction over Cu/ZSM-5 Zeolite Catalysts

采用液态离子交换法制备了不同Cu含量的Cu/ZSM-5分子筛催化剂.对其理化特性和在NH3-选择性催化还原反应中催化性能的评价结果表明:Cu元素主要以Cu+离子的形式富集于分子筛的浅层及表面,且分散性较好.Cu质量分数低于6.39%时,NO低温转化率随Cu含量的增加而增加;而在Cu质量分数超过6.39%后,随Cu含量的增加,高温NO转化率开始衰减的温度降低.反应气流速在150,000,h-1以内时,反应气流速对Cu/ZSM-5催化剂的活性温度窗口影响不大.

Cu/ZSM-5 zeolite catalysts with different copper contents were prepared through ion-exchange liquid method. Physic-chemical properties as well as its catalytic characteristics have been investigated. Results showed that copper basically existed and dispersed on the shallow and outer surface of zeolite mainly in the form of Cu＋. When copper loading ratios were below 6.39%, adding more copper will enhance NO low temperature conversion; when copper loading ratios were larger than 6.39%, further increasing the Cu loading led to premature declining of NO conversion at relatively high temperature. The space velocity as a factor influencing catalytic activity was also studied： within 150 000 h-1, the space velocity contributed little to Cu/ZSM-5 catalytic window.