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研究了在水蒸汽存在条件下 ,以 NH3为还原剂 ,金属 /ZSM- 5催化剂和负载于 ZSM- 5上的钙钛矿结构催化剂上的 NOx 选择性催化还原 (SCR)性能 .实验结果表明 ,当反应气中通入水蒸汽时 ,各样品的催化活性均下降 ,同时伴随着 N2 选择性的增加 .而 Cu- ZSM- 5样品却表现出独特的性能 ,在所有测定样品中具有最高的 NOx转化率 (在 450℃时达到 69% ) ,当有水蒸汽存在时 ,其活性没有下降 ,反而有所增加 ,450℃时转化率达到了85% .钙钛矿结构的样品表现出一个重要特性 ,其对 NOx 的 SCR反应具有很高的 N2 选择性 ,特别在水蒸汽存在条件下 ,副产物 N2 O的选择性非常低 ,几乎为零 .其中 L a Fe O3样品的催化性能最佳 .
The selective catalytic reduction (SCR) of NOx on NH3 as reductant, metal / ZSM-5 catalyst and perovskite catalyst supported on ZSM-5 was studied in the presence of water vapor.The experimental results show that, When steam was introduced into the reaction gas, the catalytic activity of each sample decreased with the increase of N2 selectivity, while the Cu-ZSM-5 sample showed unique properties with the highest NOx conversion in all the samples tested (69% at 450 ° C), the activity did not decrease with the presence of water vapor, but increased with 85% conversion at 450 ° C. The samples with perovskite structure showed an important property, It has high N2 selectivity for NOx SCR reaction, especially for the presence of water vapor, the selectivity of by-product N2 O is very low, almost zero. Among them, the catalytic activity of L a Fe O3 sample is the best.