摘要
以涂覆铜沸石的壁流式碳化硅SCRF(SCR catalysts coated DPF)为研究对象,对在SCRF壁面进行的碳烟氧化、NH3吸附及NOx还原反应过程进行模拟计算。计算结果表明:450℃时SCRF对NOx具有的最大转化率,并对PM有较高的氧化速率。随着NO2/NOx的增加,NH3吸附覆盖度降低,当NO2/NOx=0.5时,能同时达到较高的碳烟和NOx转化效率。增大氨氮比(ANR)和基底的比表面积,能提高NOx和PM的转化效率。沉积在SCRF壁面的滤饼层碳烟增大了NH3的物理吸附,同时碳烟的被动再生生成的NO组分改变了局部的NO2/NOx,能提高快速SCR的反应速率,因而增大了SCRF对NOx的还原效率。本研究能为新型后处理器SCRF在柴油机尾气系统中的应用提供理论基础。
Well-established multidimensional mathematical models for transient thermal and chemical phenomena were used to study soot oxidation, NH3 adsorption and NQ reduction process. The simulation results show that SCRF has a maximum NOx conversion rate and a higher PM oxidation rate at 450℃. NH3 adsorption coverage is reduced with the increase of NO2/NOx. Soot oxidation and NOx reduction can be effectively obtained with 0. 5 NO2/NOx. Increasing ANR（NH3/NOx ） equivalence ratio and substrate specific area can raise the conversion rates of NOx and PM. Soot cake deposited on the SCRF wall may strengthen the physical adsorption of NH3, and the NO composition generated by the passive regeneration of soot will change the local NO2/NOx, which can improve fast SCR reaction rate, and then increase the NOx reduction efficiency. This research can provide a theoretical basis for the application of novelty SCRF after-treatment device to diesel exhaust system.
出处
《内燃机工程》
EI
CAS
CSCD
北大核心
2016年第1期38-43,50,共7页
Chinese Internal Combustion Engine Engineering
基金
国家自然科学基金项目(51276128)
云南省科技厅面上项目(2013FB017)
云南省人才培养项目(KKSY201256142
KKSY201202143)
云南省教育厅项目(2012Y517)
