H2O对钒钛催化剂快速SCR反应影响规律及机制研究  

New Insights Into the Effect of H2O on the “Fast SCR” Reaction of V2O5/Ti Catalyst

作　　者：薛宗国 杜学森[1] 王向民 陈艳容[1] 闫云飞[1] 冉景煜[1] XUE Zongguo;DU Xuesen;WANG Xiangmin;CHEN Yanrong;YAN Yunfei;RAN Jingyu(Chongqing University,School of Energy and Power Engineering,Key Laboratory of Low-grade Energy Utilization Technology and System,Ministry of Education,Chongqing 400044,China)

机构地区：[1]重庆大学能源与动力工程学院,低品位能源利用技术及系统教育部重点实验室,重庆400044

出　　处：《工程热物理学报》2022年第7期1976-1985,共10页Journal of Engineering Thermophysics

基　　金：国家自然科学基金资助项目(No.52176100);国家重点研发计划政府间国际科技创新合作专项(No.2021YFE0110800)。

摘　　要：相比常规烟气气氛中的选择性催化剂还原脱硝(SCR)反应,商用钒钛(V_(2)O_(5)/TiO_(2))催化剂在NO加入后构成的快速SCR反应气氛中具备优异的低温脱硝反应性能,快速SCR反应被认为具有良好的低温脱硝应用前景。烟气中存在的水蒸气会严重降低SCR催化剂在低温下的脱硝活性,因此本文重点研究了水蒸气对钒钛催化剂上标准及快速SCR反应的影响,发现快速SCR反应比标准SCR反应具备更优异的抗水性能。本文采用动力学实验结合密度泛函理论计算的研究方法,得到H_(2)O和NH_(3)在催化剂表面的竞争性吸附是H_(2)O抑制标准SCR反应的重要影响因素之一,而在快速SCR反应中,NO对催化剂的快速重氧化作用使得反应速率始终保持在较高水平,削弱了H_(2)O对NH_(3)的竞争性吸附影响,从而了展现良好的抗H_(2)O影响性能。Compared with the selective catalyst reduction(SCR) reactions under the conventional conditions,the commercial vanadium-titanium(V_(2)O_(5)/TiO_(2)) catalyst shows excellent lowtemperature denitrification performance under the “Fast SCR” conditions in the presence of NO,which indicates a promising application prospect for low-temperature denitrification.The water vapor in the flue gas will seriously reduce the denitrification activity of the SCR catalysts at low temperatures.Therefore,this work focuses on the effect of water vapor on the vanadium-titanium catalyst under the standard and fast SCR conditions.It is found that the fast SCR reaction is better than the standard SCR reaction for water resistance performance.In this work,kinetic experiments combined with density functional theory calculations are used to investigate the competitive adsorptions of H_(2)O and NH_(3)on the catalyst surface.The results indicate that H_(2)O is one of the important influencing factors that inhibit the standard SCR reaction.Under the fast SCR conditions,the presence of NOpromotes the re-oxidation rates to keep the overall reaction rates at a high level continuously which weakens the competitive adsorption effect of H_(2)O on NH_(3),resulting in good resistance to H_(2)O.

关 键 词：氮氧化物 低温选择性催化还原 快速SCR反应 密度泛函理论 

分 类 号：TK123[动力工程及工程热物理—工程热物理]