基于NH3-SCR反应铜基小孔分子筛催化剂Na中毒对比研究  

Comparison study of Na poisoning effect on copper-based chabazite micropore catalysts for NH3-SCR reaction

作　　者：王晨 陈泽翔 王建强[1] 沈美庆[1,3] 王军[1] WANG Chen;CHEN Zexiang;WANG Jianqiang;SHEN Meiqing;WANG Jun(School of Chemical Engineering and Technology,Tianjin University,Tianjin 300350,China;School of Environmental and Safety Engineering,North University of China,Taiyuan 030051,Shanxi,China;State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学化工学院,天津300350 [2]中北大学环境与安全工程学院,山西太原030051 [3]天津大学内燃机国家重点实验室,天津300072

出　　处：《化工学报》2020年第12期5551-5560,共10页CIESC Journal

基　　金：国家重点研发计划项目(2017YFC0211302);国家自然科学基金青年基金项目(21908207);中国博士后科学基金项目(2020M670659)。

摘　　要：以浸渍法模拟碱金属中毒NH3-SCR催化剂过程,制备不同Na含量(质量分数)的铜基小孔分子筛Cu/SSZ-13和Cu/SAPO-34,对比研究了二者的碱金属中毒机理。结果表明,外引Na离子均可严重影响两种催化剂的NH3-SCR催化活性,造成催化剂的晶相结构坍塌,酸性量减少,活性物种减少。不同的是,Na引入量较低(<1.82%)时,Cu/SAPO-34比Cu/SSZ-13具有更强的Na离子耐受性,而当Na含量高于3.48%时,Cu/SAPO-34几乎完全丧失NH3-SCR催化活性。通过催化剂的结构表征(BET、XRD和SEM)和酸性位表征(DRIFTS、NH3-TPD和H2-TPR),研究表明随着Na中毒程度的加深,Cu/SSZ-13的结构破坏是渐变式的,而Cu/SAPO-34的结构破坏是突变式的;Na中毒的机理研究表明,酸性位的减少是Cu/SSZ-13的SCR活性下降的主导原因,结构坍塌是Cu/SAPO-34的SCR活性下降的主导原因。Using wet impregnation method to mimic alkali metal poison of ammonia-selective catalytic reduction(NH3-SCR)catalysts,Cu-based micropore zeolites Cu/SSZ-13 and Cu/SAPO-34 with different Na contents(mass fraction)were prepared,and the Na poisoning mechanism on them was studied.The results show that the externally introduced Na ions can severely affect the NH3-SCR catalytic activity of the two catalysts,resulting in the collapse of the crystal structure of the catalyst,the decrease of acidity and the reduction of active species.In detail,when Na content was less than 1.82%,Cu/SAPO-34 has higher resistance of Na ions than Cu/SZZ-13;while when Na>3.48%,Cu/SAPO-34 catalysts almost deactivated thoroughly.By structural characterization(BET,XRD and SEM)and acidity characterization(DRIFTS,NH3-TPD and H2-TPR),it was found that with Na poisoning deeper and deeper,Cu/SSZ-13 took a gradual style of the structural destruction,but Cu/SAPO-34 adopted a sudden way.Studies on the mechanism of Na poisoning show that the decrease of acid sites is the main reason for the decrease of SCR activity of Cu/SSZ-13,and the structural collapse is the main reason for the decrease of SCR activity of Cu/SAPO-34.

关 键 词：选择性催化还原 碱金属 分子筛 催化剂 氮氧化物 中毒机理 

分 类 号：TQ028.8[化学工程]