国六柴油机DPF再生时VOCs排放特性 |
摘要点击 3132 全文点击 1025 投稿时间:2019-06-03 修订日期:2019-08-22 |
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中文关键词 颗粒物捕集器(DPF) 挥发性有机物(VOCs) 再生 排放因子 排放特性 |
英文关键词 diesel particulate filter (DPF) volatile organic compounds (VOCs) regeneration emission factor emission characteristics |
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中文摘要 |
颗粒物捕集器(DPF)是柴油机满足国六排放标准的必备装置之一.经台架实验证明,氧化型催化转化器(DOC)辅助DPF再生过程中挥发性有机物(VOCs)排放会大幅度升高,而2014年制定的《道路机动车大气污染物排放清单编制技术指南》并未考虑到DPF再生过程对VOCs排放的影响.通过台架实验,采集国六柴油机DPF再生过程的尾气,并用气相色谱质谱技术对尾气中的VOCs进行定量分析.结果表明,国六柴油机DPF再生过程中VOCs排放有显著增加,DPF再生阶段排放的VOCs总量是不再生时的4倍,增排量为2419.6 μg·m-3,且DPF再生所排放的VOCs中,烷烃的含量最高,其次为芳香烃、醛酮和烯烃,分别占总排放VOCs的42.5%、29.7%、24.9%和2.9%;用臭氧和二次有机气凝胶生成潜势对增排VOCs的大气活性进行评价,发现DPF再生过程中增排的VOCs对环境的影响显著,由增排的VOCs所生成的臭氧和二次有机气溶胶分别为4272.8 μg·m-3和9.0 μg·m-3,其中芳香烃和烷烃对臭氧和二次有机气溶胶生成潜势的贡献率相对较高.因此,在计算柴油车VOCs排放因子时,应考虑DPF再生的影响;且该国六柴油机DPF再生时的VOCs排放因子为1.03 mg·(kW·h)-1,可为制定国六标准柴油车VOCs排放因子提供参考. |
英文摘要 |
The diesel particulate filter (DPF) is one of the necessary devices required for diesel engines to meet the National Ⅵ emission standards. In this study, its function is tested in bench experiments, showing that the emission of volatile organic compounds (VOCs) during the regeneration of DPF assisted by the oxidized catalytic converter (DOC) is significantly increased. The "calculation guide of air pollutant emission for road vehicles" formulated in 2014 did not take into account the impact of the DPF regeneration process on VOCs emission. The tail gas of the DPF regeneration process of the National Ⅵ diesel engine was collected in the bench test, and the VOCs in the exhaust gas were quantitatively analyzed by gas chromatography mass spectrometry. Results show that the VOC emissions in the DPF regeneration process increased significantly. The total amount of VOCs is four times that during non-regeneration, and the increase is 2419.6 μg·m-3. The VOCs emitted by DPF regeneration have the highest alkane content, followed by aromatic hydrocarbons, aldehydes and ketones, and olefins, which account for the total emission of VOCs, namely 42.5%, 29.7%, 24.9% and 2.9%, respectively. Using the generation potential of ozone and secondary organic aerogel to evaluate the atmospheric activity of VOCs, we found that the increased VOCs during DPF regeneration had a significant impact on the environment. The ozone and secondary organic aerosols generated by the increased VOCs were 4272.8 μg·m-3 and 9.0 μg·m-3, respectively. The aromatic hydrocarbons and alkanes contributed the most significantly to the ozone and secondary organic aerosols. Therefore, the impact of DPF regeneration on VOCs emissions from diesel engines should be considered. From the calculation, the VOCs emission factor of the DPF regeneration is 1.03 mg·(kW·h)-1, which can serve as a reference for the development of National Ⅵ diesel vehicle VOCs emission factors. |
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