四元SCR催化剂V_2O_5-WO_3-MoO_3/TiO_2脱硝性能

DeNO_x performance of quaternary SCR V_2O_5-WO_3-MoO_3/TiO_2 catalyst

以锐钛型TiO2为载体,V2O5为主要活性成分,同时负载WO3和MoO3作为活性助剂,制备了四元催化剂V2O5-WO3-MoO3/TiO2,并对该催化剂的脱硝活性、催化选择性及微观表征进行了研究。结果表明,该四元催化剂脱硝性能优于相同负载量下单一负载W或Mo的三元催化剂,W可以提高催化剂高温(>400℃)活性,同时抑制Mo在高温区间导致的副反应发生,Mo可以提高低温(<300℃)活性,弥补W在低温区间的活性不足。该四元催化剂最大活性99%,温度窗口(脱硝活性>80%)为280～420℃,在180～380℃范围内SO2氧化率为零,在0～1000℃范围内存在3个失重峰,100～130℃结晶水蒸发,230～270℃有机添加剂分解,500～530℃无机盐分解,微观镜像表明该催化剂颗粒均匀致密,粒径大小一致,没有出现团聚现象,具有完整的微孔结构。

The quaternary SCR catalyst was prepared with anatase TiO2 as the support,V2O5 as the main active agent,WO3 and MoO3 as the active coagent.The deNOx efficiency,catalytic selectivity,thermo stability and microscopic characterization of this catalyst were studied.The results showed that the deNOx efficiency of this quaternary catalyst was higher than the ternary catalyst singly loading W or Mo at the same weight percent.W improved the deNOx efficiency at high temperature and inhibited the side reaction caused by Mo at the temperature above 400℃,while Mo improved the deNOx efficiency at low temperature which made up for the lower deNOx efficiency of W at the temperature below 300℃.The maximum deNOx efficiency of this quaternary catalyst was 99%,the temperature window（deNOx efficiency80%） was 280-420℃,and the SO2 oxidation in the range of 180-380℃ was zero.There were three weight loss peaks for the quaternary catalyst in the range of 0-1000℃,crystal water evaporation at 100-130℃,organic additive decomposition at 230-270℃ and inorganic salt decomposition at 500-530℃.The microscopic characterization showed the particle of this catalyst was uniform and compact,the grain size was consistent with no apparent agglomeration and macro pore structure was complete.