摘要
鉴于柴油机选择性催化还原系统尿素喷射特性与氮氧(NO_x)转化效率密切相关,本文搭建SCR系统小样试验台,NO和NH_3作为主要试验用气,研究了不同氨氮比和不同温度条件下V_2O_5-WO_3/TiO_2催化剂的氨存储、氨泄漏以及NO_x转化效率的影响.结果表明:氨氮比越大,氨存储量的建立时间越短,NO_x转化效率的提升就越快;氨氮比为0.22时,15s内NO_x转化效率从0增大到4.3%;当氨氮比为0.30时,15s内NO_x转化效率从0增大到8.7%;随着氨氮比的增大氨泄漏会提前出现;氨氮比先大后小的喷射方法有利于改善NO_x转化效率.采用氨氮比先大后小的喷射方法,进行ETC标准循环测试,NO_x比排放从8.26g/(kW·h)减少到1.91g/(kW·h),NH_3泄漏均值为5×10^(-6),峰值为18×10^(-6),满足国V排放法规要求.
The characteristics of urea injection and NOx conversion efficiency are closely related.A SCR test bench was built based on V2O5-WO3/TiO2 catalyst,and NO,NH3 and O2 feed streams were dosed by mass flow controllers.The effect of normalized stoichiometric ratio（NSR）and catalyst temperature on ammonia storage,ammonia slip and NOx conversion efficiency was studied.The results show that the influence of NSR and temperature on ammonia storage,ammonia slip and NOxconversion efficiency is obvious.The time of ammonia storage will be shorten with the increase of NSR,then the improving speed of NOx conversion efficiency is high.The NSR fix 2.2,the NOx reduction efficiency increase from 0 to 4.3% within 15 s,and the NOx reduction efficiency increase from 0 to 8.7% within 15 swhen NSR set 3.0.The time of ammonia slip and ammonia storage are closely related,the time of ammonia slip will be shorten with the increase of NSR.The method of NSR from larger to the smaller can increase ammonia storage rate and optimize NOx conversion efficiency.Using this injection method to carry out the European transient cycle（ETC）test,the brake specific emission of NOx reduce from 8.26 g/（kW·h）to 1.91 g/（kW·h）,and the average and peak value of ammonia are 5×10^-6 and 18×10^-6,the NOx can reach the National V emission regulations.
作者
岳广照
刘兴华
孙柏刚
仇滔
姚小刚
YUE Guang-zhao1 , LIU Xing-hua1 , SUN Bai-gang1 , QIU Tao2 , YAO Xiao-gang3(1. School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; 2. College of Environment and Energy Engineering, Beijing University of Technology, Beijing 100124, （ 3. Hu＇nanJatech INC, Changsha, Hu＇nan410138, China)
出处
《北京理工大学学报》
EI
CAS
CSCD
北大核心
2018年第2期143-149,共7页
Transactions of Beijing Institute of Technology
基金
国家国际科技合作专项基金资助(2013DFR70170)
北京市教委促进人才培养综合改革基金项目(JZ005011201401)
关键词
柴油机
选择性催化还原
尿素喷射方法
氮氧转化效率
diesel engine
selective catalytic reduction （SCR）
urea injection method
NOx conversion efficiency
