低温烟气脱硝催化剂适用条件与动力学  

Application conditions and kinetics simulation over SCR catalyst for flue gas denitrification under low temperature

作　　者：李萍 李长明[1] 段正康[2] 高士秋[1] 许光文[3] 余剑[1] LI Ping;LI Changming;DUAN Zhengkang;GAO Shiqiu;XU Guangwen;YU Jian(State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences,Beijing 100190, China;School of Chemical Engineering, Xiangtan University, Xiangtan 411105, Hunan, China;Shenyang University of Chemical Technology, Shenyang 110142, Liaoning, China)

机构地区：[1]中国科学院过程工程研究所多相复杂系统国家重点实验室,北京100190 [2]湘潭大学化工学院,湖南湘潭411105 [3]沈阳化工大学,辽宁沈阳110142

出　　处：《化工学报》2019年第8期2981-2990,共10页CIESC Journal

基　　金：国家自然科学基金青年基金项目(21601192);中日政府间国际合作项目(2016YFE0128300);多项复杂系统国家重点实验室自主研究课题项目(MPCS-2017-A-06,MPCS-2017-D-11)

摘　　要：随着国家对大气污染物排放要求的进一步提高,中低温脱硝催化剂也将迎来更大的市场和挑战。为进一步明确低温脱硝催化剂的应用特性,在不同温度、烟气流速、催化剂长度和水蒸气含量下对已产业化的蜂窝催化剂的脱硝活性进行了系统考察,获得该中低温脱硝催化剂的适用区间与动力学参数。实验表明,在温度高于160℃条件下,通过调变气速与催化剂长度可以实现理论氨氮比的脱硝率;且在考察水蒸气对脱硝活性的影响时,发现脱硝率随着水蒸气含量的增加而逐步降低,在低温条件下降低更加显著,最大降幅达30%;依据2~4 m/s气速下的脱硝率与停留时间的关系,拟合脱硝反应活化能为22.7 kJ/mol,属于典型的气体外表面扩散控制,可为低温脱硝催化剂选型提供重要参考;180000 m^3/h烟气量的脱硝示范验证了该催化剂在180℃下脱硝率超过90%,显示了优良的工业应用和推广前景。With the more stringent requirements of atmospheric pollutant emission standards, medium and low temperature catalyst would have larger market and greater challenge. In order to further clarify the application characteristics of the low temperature denitration catalyst, the denitration activity of the industrialized honeycomb catalyst was systematically investigated under different temperatures, flue gas flow rate, catalyst length and water vapor content. The applicable temperature range and kinetic parameters of the catalyst under low temperature window were also determined. These results showed that theoretical denitrification rate of NH3/NO can be achieved above 160℃ by adjustments of gas velocity and length of honeycomb catalyst. Moreover, it was found that NO conversion gradually decreased with the increase of steam content, and the negative impact become more severely below 180℃ with less than 70% DeNOx efficiency at 160℃ and 35% steam content in flue gas. According to the relationship between denitrification rate and residence time(at 2-4 m/s gas velocity), the reaction activation energy was calculated to be 22.7 kJ/mol, suggesting that the reaction is limited by the external diffusion. The industrial DeNOx demonstration of flue gas with 180000 m^3/h over this catalyst exhibits more than 90% DeNOx efficiency at 180℃ and promising industrialization prospect.

关 键 词：选择性催化还原 低温催化剂 操作范围 工业示范 动力学参数 

分 类 号：TQ028.8[化学工程]