摘要
以柴油车实际使用失效的SCR装置为研究对象,采用氨气程序升温脱附(NH 3-TPD)、X射线衍射(XRD)、X射线光电子能谱(XPS)、比表面积测试(BET)、扫描电子显微镜(SEM)和X射线荧光光谱(XRF)测试对其进行宏观性能评价和微观结构表征试验,分析研究劣化件结构参数变化,研究SCR装置的失活机理。结果表明:SCR装置劣化可归结于热老化和硫中毒。热老化会使催化剂骨架坍塌,颗粒团聚,降低比表面积,使孤立态活性Cu^(2+)会转化为低活性的CuO物种,减少其表面的BrΦnsted酸性位点数量。硫中毒导致硫元素燃烧生成的硫酸盐覆盖在催化剂表面,堵塞孔道,减少表面活性位点,降低SCR装置的低温活性。
With failed Selective Catalyst Reduction(SCR)devices of in-use diesel vehicles as the research objects,this paper carries out their performance evaluation and microstructure characteristics test to analyze the structural parameter change of deteriorated parts and verify the deterioration mechanism of SCR catalyst through a series of tests,namely,the temperature programmed desorption of ammonia(NH 3-TPD),diffraction of X-rays(XRD),X-ray photoelectron spectroscopy(XPS),Brunauer-Emmett-Teller(BET),scanning electron microscope(SEM),and the X-ray fluorescence spectrometry(XRF)tests.The results show that the deterioration of SCR devices can be attributed to thermal aging and sulfur poisoning.Thermal aging of SCR results in the collapse of catalyst skeletons,and agglomeration of molecular sieves,which in return reduces the specific surface area so that the active Cu^(2+)in the isolated state is converted to the less active CuO species,reducing the number of Br nsted acid sites on its surface.Sulfur poisoning results in the sulfates generated by combustion of sulfur to cover the catalyst surface,thus clogging the pore channels,reducing surface active sites,and decreasing the low temperature activity of the SCR devices.
作者
朱自如
黄鹏
王素梅
吕立群
葛蕴珊
ZHU Ziru;HUANG Peng;WANG Sumei;LYU Liqun;GE Yunshan(School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100081,China;Weichai Power Co.,Ltd.,Weifang 261001,China)
出处
《重庆理工大学学报（自然科学）》
CAS
北大核心
2022年第12期216-222,共7页
Journal of Chongqing University of Technology：Natural Science
基金
青海省重大科技专项项目(2019-GX-A6)。
关键词
分子筛催化剂
劣化机理
热老化
硫中毒
molecular sieve catalyst
deterioration mechanism
thermal aging
sulfur poisoning
