柴油机后处理系统材料腐蚀对催化剂性能的影响
李俊普1,2，陈宁1,2，刘伟达1,2，杨起1,2
1.内燃机可靠性国家重点实验室，山东 潍坊 261061；
2.潍柴动力空气净化科技有限公司，山东 潍坊 261061
摘要：研究后处理系统材料腐蚀对催化剂性能的影响。以NOx转化效率为评价指标，通过对问题后处理系统样件进行台架性能复测、催化剂小样测试分析、电镜扫描和X射线能谱分析等，分析后处理系统材料腐蚀对催化剂性能的影响规律，并通过不锈钢材料性能分析和台架耐腐蚀测试进行材料优选。分析结果表明：沿气体流动方向的第一段A-SCR催化剂进气端和出气端NOx转化效率不一致，催化剂进气端面被铁蚀导致催化剂NOx转化效率下降；第二段B-SCR和第三段C-SCR/ASC催化剂NOx转化效率和新鲜态样件性能差异很小。电镜扫描和X射线能谱分析结果表明：在第一段A-SCR催化剂进气端面发现有Fe、Ni等元素存在，锈蚀是催化剂NOx转化效率下降的主要因素。不锈钢材料性能分析和台架耐腐测试验证结果表明，SUS444不锈钢抗腐蚀性能较好，满足关键零部件的使用要求。
关键词：后处理系统；材料腐蚀；催化剂；NOx转化效率；台架测试
Influence of corrosion of diesel aftertreatment materials on catalyst performance
LI Junpu1,2, CHEN Ning1,2, LIU Weida1,2, YANG Qi1,2
1. State Key Laboratory of Engine Reliability, Weifang 261061，China；
2. Weichai Power Emission Solutions Technology Co., Ltd., Weifang 261061，China
Abstract：The influence of material corrosion of aftertreatment system on catalyst performance is studied. Taking the NOx conversion efficiency as the evaluation indicator, the effect of material corrosion of the aftertreatment system on catalyst performance is analyzed through bench performance test, catalyst sample test analysis, electron microscope scanning and X-ray energy spectrum analysis of the sample of the problem aftertreatment system, and the material is optimized through stainless steel material performance analysis and bench corrosion resistance test. The analysis results show that the NOx conversion efficiencies of the inlet and outlet ends of the first stage A-SCR catalyst along the gas flow direction are inconsistent, and the iron corrosion of the inlet of the catalyst leads to the decrease of the NOx conversion efficiency of the catalyst. There is little difference between the NOx conversion efficiency of the second stage B-SCR and the third stage C-SCR/ASC catalysts and the performance of the fresh samples. The results of electron microscope scanning and energy dispersive X-ray analysis show that Fe, Ni and other elements are found on the inlet of the first stage A-SCR catalyst, and corrosion is the main factor for the reduction of NOx conversion efficiency of the catalyst, not high temperature degradation. The results of performance analysis of stainless steel and corrosion resistance test on the bench show that SUS444 stainless steel has good corrosion resistance and meets the requirements of key parts.
Keywords:aftertreatment system; material corrosion; catalyst; NOx conversion efficiency; bench test
