柴油机Urea-SCR系统NOx转化效率  

Study on Influence Factors of NOx Conversion Efficiency of DieselUrea-SCR System

作　　者：焦运景[1,2,3] 纪晓静 纪丽伟 

机构地区：[1]上海柴油机股份有限公司,上海200438 [2]天津大学机械工程学院,天津300072 [3]北华航天工业学院,廊坊0650003

出　　处：《柴油机设计与制造》2015年第2期16-19,40,共5页Design and Manufacture of Diesel Engine

基　　金：上海市博士后科研资助计划资助,项目编号：14R21420600;河北省自然科学基金资助,项目编号：E2015409022;廊坊市科技支撑计划项目,项目编号：2014011054

摘　　要：概述了尿素选择性催化还原（Urea-SCR）技术的机理及其基本化学反应.在发动机台架试验的基础上,应用数值计算软件,针对发动机不同工况进行了数值计算,详细分析研究了氨氮比、排气温度及空速对催化转化效率的影响.通过数值计算,得出氨氮比的变化对氮氧化物（NOx ） 转化效率的影响规律,可快速确定柴油机指定工况下的NOx最大转化效率,将氨泄漏量控制在最低范围内;随着排气温度升高,NOx转化效率呈先升高后下降的趋势;随着空速的增大,转化效率有所降低,且变化程度随着排温的变化而有所不同..This paper provides an overview of the mechanism of urea selective catalytic reduction（Urea-SCR） technology and the basic chemical reactions. Based on bench test, numerical calculation indifferent engine operating conditions is carried out. The effect of exhaust temperature, ammonia ratio andspace velocity on conversion efficiency is studied through numerical simulation software. With the numericalcalculation, the effect of ammonia ratio on de-NOx rate is obtained, with which the maximum conversion ratein specified conditions of diesel engine can be quickly determined to control the ammonia leakage in thelowest range. NOx conversion rate increases at first and then declines with exhaust temperature rising. Theconversion efficiency reduces with the increase of space velocity and changes with exhaust temperature.

关 键 词：柴油机 氮氧化物 选择性催化还原 转化率 

分 类 号：X511[环境科学与工程—环境工程]