柴油机NOx存储耦合在线选择性催化还原的协同机理研究

项目名称： 柴油机NOx存储耦合在线选择性催化还原的协同机理研究

项目编号： No.51476021

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 能源与动力工程

项目作者： 苏庆运

作者单位： 大连理工大学

项目金额： 83万元

中文摘要： NOx存储耦合在线选择性催化还原（NSR-SCR）技术具备结构简单、无需额外氨源、较低的贵金属使用量和较高的NOx去除效率等优点，然而该系统对NOx的协同去除机理，尤其是NH3/HC-双SCR反应机理并不明确。在前期研究NSR系统的基础上，制备并表征以Pt/Pd/Rh为主要活性成分的NSR催化剂及Cu分子筛、Fe分子筛SCR催化剂，设计模拟尾气成分稀、浓瞬变实验，研究关键组分和中间产物的生成规律及反应过程。综合运用微观反应动力学原理、密度泛函理论（DFT）、键指数归一-二次指数势（UBI-QEP）方法，确定关键反应步及动力学参数，建立表面催化详细化学反应动力学机理。对NSR-SCR系统进行从分子尺度到多维反应流动尺度的全过程多尺度仿真研究，开展发动机台架实验验证催化剂小样实验及模拟结果。探索降低贵金属使用量及提高催化剂低温、高温活性的方案，为优化NSR-SCR系统提供理论基础和技术支持。

中文关键词： 柴油机；氮氧化物；存储还原；选择性催化还原；详细机理

英文摘要： The NOx storage coupled with in-situ selective catalytic reduction (NSR-SCR) is a combination system, which provides the benefits of simple structure, no external source of NH3, low precious metal consumption, and high NOx abatement efficiency. However, the mechanism of NOx reduction, especially for the synergetic mechanism of NH3 and HC over SCR catalyst, is not clear. On the basis of previous studies on NSR-only system within our group, Pt/Pd/Rh based storage and reduction catalyst and Cu-zeolite, Fe-zeolite based SCR catalyst are prepared and characterized for lean/rich transient and steady state experiments. Simulated diesel exhaust gases are employed both in transient and steady state experiments to characterize the processes of NOx reduction and the formation of the key intermediates. Some crucial kinetic parameters of elementary reactions are to be determined by density functional theory (DFT) and unity bond index-quadratic exponential potential (UBI-QEP) methods. Multi-dimensional modeling, from molecular level to multi-dimensional reactive flow scale, is carried out for thoroughly studying the NSR-SCR system. The model validation is performed by comparing the simulation results and the data achieved from diesel bench test. The purpose of this project is to explore possible solutions for minimizing the amount of precious metal and improving the low and high temperature activity of the catalyst. It is expected the project will offer some fundamental support for systematic design of NSR-SCR system.

英文关键词： Diesel Engine;Nitrogen Oxides;Storage and Reduction;Selective Catalytic Reduction;Detailed Mechanism