柴油机超低排放后处理系统及催化剂的研发探讨

Research and Development of After-treatment System and Catalyst for Ultra-low Emission of Diesel Engine

随着排放限值的加严和发动机排放温度的降低,我国目前的国六后处理系统可能无法满足限值要求。文章就后处理系统及催化剂的研究发展进行了探讨。前置选择性催化还原(SCR)被认为是一套具有发展前景的后处理系统,在冷启动时较国六后处理系统能较好控制低温NO_(x)排放。文章针对前置SCR系统中可能出现的问题进行了分析及验证。结果表明,前置SCR在碳氢中毒、端面堵塞等问题上,可以通过调整催化剂来解决。因此,前置SCR系统是一套可行的、风险较低的后处理系统。

With the stricter emission limits and the requirement on decreasing of engine emission temperature,the existing national VI after-treatment system may be difficult to meet the limit requirements.This paper discussed the future evolution of after-treatment system.The cc-SCR(close-couple SCR)system is considered to be one of promising systems,because it shows great benefit in low-temperature NOx emission control at cold-start cycle when compared to the national VI system.The problems that may occur in the cc-SCR system were analyzed and verified.The results show that the problems such as surface blocking and HC poisoning in cc-SCR can be solved by adjusting the catalyst.Therefore,the cc-SCR system is a feasible and low-risk after-treatment system.