Ce-Fe/ZSM-5催化剂用于燃机烟气SCR脱硝的性能

采用浸渍法制备了一系列Ce?Fe/ZSM-5催化剂，基于燃机烟气工况研究了Fe含量及Ce掺杂量对Fe/ZSM-5催化剂的中高温脱硝性能的影响，并结合一系列表征技术对其物化性能进行研究。结果表明，Fe含量为4wt%时，Fe/ZSM-5催化剂在550℃下NOx转化率为77.11%。掺杂Ce后Ce?Fe/ZSM-5催化剂的高温脱硝效果明显提升，Ce负载量为1wt%时，550℃时NOx转化率仍保持95.92%，催化剂有优异的中高温催化活性，比Fe4/ZSM-5提高了18.81%。同时改变烟气中的NO2和O2含量，发现NO2和O2浓度增加均可提高催化剂的脱硝性能，水热老化测试表明Ce1?Fe4/ZSM-5催化剂具有优异的水热稳定性，分别在10vol% H2O, 600℃和10vol% H2O, 800℃条件下老化后，在450?550℃内NOx转化率保持约90%。适量掺杂Ce后催化剂表面Lewis酸含量及强度增强，表面吸附氧比例增大，Ce与Fe元素间的协同作用提高了催化剂的高温氧化还原能力，提升了高温活性，因此促进了中高温条件下SCR反应的进行。

Performance of selective catalytic reduction of NOx over Ce-Fe/ZSM-5 catalysts for denitrification of gas turbines

An effective high temperature denitration catalyst hasn’t been proposed for gas turbine flue gas condition. Therefore, Ce?Fe/ZSM-5 catalyst was prepared to be used in denitration for gas turbine flue gas by impregnation method with ZSM-5 sieved as the carrier, Fe as the active component and Ce as the active additive. Based on the gas turbine flue gas condition, the physical and chemical properties such as denitrification performance, surface acidity and redox ability of the catalyst were systematically studied to research structure-activity relationship between catalyst structure and denitration effect. The results showed that when the Fe load was 4wt%, the NOx conversion rate of Fe/ZSM-5 catalyst was 77.11% at 550℃. The high temperature denitrification effect of Ce?Fe/ZSM-5 catalyst was significantly improved after Ce doping. When the Ce load was 1wt%, the NOx conversion rate remained at 95.92% at 550℃, the catalyst had excellent medium-high temperature catalytic activity, which was 18.81% higher than that of Fe4/ZSM-5. Moreover, the increase of oxygen content and NO2 concentration can improve the selective catalytic reduction (SCR) performance of the catalyst. The hydrothermal aging test showed that the catalyst had good hydrothermal stability. After aging at 10vol% H2O, 600℃ and 10vol% H2O, 800℃, the NOx conversion rate of catalyst was maintained about 90% in the range of 450?550℃. Characterization results indicated that proper cerium doping can promote the dispersion of iron oxides, enhance the content and strength of Lewis acid site, and increase the proportion of absorbed oxygen, the synergistic effect between Ce and Fe also improved the redox ability of catalyst at high temperature, these might be the reason for the better high temperature catalytic activity.