DOC和金属基DPF对柴油机排气颗粒物表面官能团演化特性的影响  

Effect of DOC and Metal-based DPF on the Evolution of Surface Functional Groups on PM from Diesel Engine Exhaust

作　　者：李博[1] 刘顺涛[1] 杨鹤[1] 陶志平[1] 卢文彤[1] 丁晓亮[1] 邢建强[1] Li Bo;Liu Shuntao;Yang He;Tao Zhiping;Lu Wentong;Ding Xiaoliang;Xing Jianqiang(Research Institute of Petroleum Processing,Beijing,100083,China)

机构地区：[1]石油化工科学研究院

出　　处：《小型内燃机与车辆技术》2019年第6期52-59,共8页Small Internal Combustion Engine and Vehicle Technique

基　　金：国家重点基础材料技术提升与产业化（2017YFB0306605）

摘　　要：开展不同工况下普通商用DOC和金属过滤载体DPF对柴油机排气颗粒物(PM)表面官能团影响机制的研究,结果表明:在DOC中催化剂和高温作用下,PM表面甲基、亚甲基官能团氧化速率相近,DOC对PM表面A2958/A2928比值影响不大;DOC中,PM表面C=O官能团比C-O官能团具有更高的氧化速率,且PM表面碳氢官能团比碳氧官能团也具有更高的氧化速率,导致经DOC处理后,PM的A(C=O)/A(C-O)比值及表面碳氢官能团含量显著减少。金属过滤载体DPF中排气温度较低且无贵金属催化作用,PM表面稳定性较差的亚甲基在DPF中优先氧化,而PM表面C=O、C-O官能团在DPF中的氧化速率均比较缓慢,导致经DPF处理后,PM样品的A2958/A2928比值均显著提高,A(C=O)/A(C-O)比值变化不大,而A(CH3+CH2)/A(C-O+C=O)比值均小幅下降;DPF中,几种表面官能团氧化速率均较低,但在排气温度较高的工况,亚甲基的氧化速率还是稍快于其它几种官能团的氧化速率。In this paper the evolution of surface functional groups on particulate matter(PM) affected by the commercial diesel oxidation catalyst(DOC) and the metal-based diesel particulate filter(DPF) was studied under different conditions of diesel engine. The obtained results show that under DOC catalyst the oxidation rates for methyl and methylene functional groups on PM surfaces were similar at high temperatures, and the DOC system had little effect on the variation of A2958/A2928 ratio. The C=O functional group on PM surface presented a higher oxidation rate than the C-O functional group, and the HC functional group had a higher oxidation rate than the carbon-oxygen functional group, leading to a lower A(C=O)/A(C-O)ratio and a significant decrease in the content of surface HC functional groups on PM after the DOC treatment. The exhaust temperature in the metal-based DPF was relatively low, and the DPF without noble metals had little catalysis effect on the PM oxidation. Thus, the oxidation of methylene groups with poorer stability on PM surface occured in priority, but the C=O and C-O functional groups were oxidated slowly through DPF. These brought the facts that the A2958/A2928 ratio increased significantly through DPF, but the A(C=O)/A(C-O)ratio changed little and the A(CH3+CH2)/A(C-O+C=O)ratio decreased slightly. Note that, the oxidation of surface functional groups of PM through DPF occured slowly under low temperatures, but the oxidation rate of methylene was promoted and was faster than that of other functional groups at higher exhaust temperatures.

关 键 词：柴油机氧化催化器(DOC) 柴油机微粒捕集器(DPF) 颗粒物(PM) 官能团 氧化反应 

分 类 号：TK421.5[动力工程及工程热物理—动力机械及工程]