摘要
为了研究国六重型柴油机选择性催化还原(SCR)系统NOx转化效率影响因素,文章采用计算流体力学(CFD)和化学反应动力学相结合的方法,对SCR催化器系统进行了数值仿真和试验验证。结果表明:SCR催化器最佳反应温度范围在180~550℃,催化器转化效率达到95%以上,不同氨氮比对NOx转化效率有一定的影响,存在一个临界氨氮比,达到该临界值后NOx转化效率趋于稳定而氨泄漏量增加;通过前置氧化型催化转化器(DOC)可在排气中增加NO2的质量分数,可以提高催化器转化效率且使NOx转化效率都能保持在较高水平,也可以除去大部分尾气中的CO和HC,达到排放标准。
In order to study the factors affecting the NOx conversion efficiency of the selective catalytic reduction(SCR) system of the National Six Heavy duty diesel engine, the numerical simulation and experimental verification of the SCR catalyst system were carried out by the combination of computational fluid dynamics(CFD) and chemical reaction kinetics. The results show that the optimum reaction temperature range of SCR catalyst is 180-550℃, and the catalytic converter conversion efficiency is over 95%. Different ammonia-nitrogen ratios have certain influence on NOx conversion efficiency. There is a critical ammonia-nitrogen ratio. After reaching this critical value, the NOx conversion efficiency tends to be stable and the ammonia leakage increases. By pre-oxidation type catalytic converter(DOC), the mass fraction of NO2 can be appropriately increased in the exhaust gas, which can improve the conversion efficiency of the catalyst and keep the NOx conversion efficiency at a high level,It can also remove CO and HC from most of the exhaust gas to meet emission standards.
作者
刘文彬
刘屹
韦伟
王再兴
余国成
王磊
宋志良
LIU Wen-bin;LIU Yi;WEI Wei;WANG Zai-xing;YU Guo-cheng;WANG Lei;SONG Zhi-liang(Anhui Aikelan Environmental Protection Co.,Ltd.,Chizhou 247100,China)
出处
《内燃机与配件》
2020年第16期30-33,共4页
Internal Combustion Engine & Parts
关键词
柴油机
数值仿真
转化效率
氨氮比
diesel engine
numerical simulation
conversion efficiency
ammonia-nitrogen ratio
