摘要
建立了柴油机选择性催化还原SCR系统的仿真模型,提出了尿素分解效率的概念。研究了排气温度、NH3存储量、NO2/NOx、NH3/NOx等关键运行参数对NOx转化率的影响。研究结果表明,随着排气流速的减小和排气温度的增加,尿素分解效率总体呈升高趋势。进行了不同温度下NOx转化率的评价试验研究,仿真结果和试验结果吻合良好。随NH3存储量的增加,NOx转化率呈上升趋势。随排气温度的升高,NOx转化率持续上升,当温度超过某一值后趋于稳定。随NO2/NOx的增加,NOx转化率逐渐上升,当NO2/NOx超过50%后,NOx转化率则有所下降;NOx转化率随NH3/NOx的增大而上升,当排气温度较高时,其影响较为明显。
A simulation model for selective catalytic reduction （SCR） of exhaust gas from diesel engine is established, and a concept of urea decomposition efficiency is proposed. Effects of exhaust gas temperature, NH3 storage, NO2/NOx ratio and NH3/NOx ratio on the NOx conversion efficiency are studied. The results show that the urea decomposition efficiency increases with decreasing exhaust gas flow rate and rising exhaust gas temperature. Special evaluating experiments for NOx conversion efficiency under various temperatures were performed. The data obtained by simulation show good agreement with the experimental results. The results show that the NOx conversion efficiency increases with the NH3 storage capacity rising. Similarly, the NOx conversion efficiency increases with rising exhaust gas temperature, and it gets stable when the exhaust gas temperature reaches a certain value. Increasing NO2/NOx ratio can also improve the NOx conversion efficiency, but the opposite phenomenon occurs when the NO2/NOx ratio is greater than 50%. With increase of NH3/NOx ratio, the NOx conversion efficiency ascends, and the influence is obvious when the exhaust gas temperature is high.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2014年第10期4063-4070,共8页
CIESC Journal
基金
国家自然科学基金项目(50906062)
国家高技术研究发展计划项目(2012AA111717)
内燃机燃烧学国家重点实验室开放基金项目(2012)~~
关键词
SCR
柴油机
污染
模型
尿素分解效率
NOx转化率
运行参数
SCR
diesel engine
pollution
model
urea decomposition efficiency
NOx conversion efficiency
operating parameter
