Qian Feng, Xue Chang-Xin, Xu Xiao-Wei, Ma Dong, Li Peng, Zhu Neng
School of Automobile and Transportation Engineering, Wuhan University of Science and Technology, Wuhan 430081, China.
State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Huan Jing Ke Xue. 2020 Feb 8;41(2):674-681. doi: 10.13227/j.hjkx.201906012.
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. 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 and 9.0 μg·m, 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), which can serve as a reference for the development of National Ⅵ diesel vehicle VOCs emission factors.
柴油颗粒过滤器（DPF）是柴油发动机达到国Ⅵ排放标准所需的必要装置之一。在本研究中，通过台架试验对其功能进行了测试，结果表明，在氧化催化转化器（DOC）辅助下DPF再生过程中挥发性有机化合物（VOCs）的排放量显著增加。2014年制定的《道路车辆空气污染物排放计算指南》未考虑DPF再生过程对VOCs排放的影响。在台架试验中收集了国Ⅵ柴油发动机DPF再生过程的尾气，并采用气相色谱-质谱联用仪对废气中的VOCs进行了定量分析。结果表明，DPF再生过程中的VOCs排放量显著增加。VOCs总量是非再生过程中的4倍，增量为2419.6μg·m。DPF再生排放的VOCs中烷烃含量最高，其次是芳烃、醛酮类和烯烃类，分别占VOCs总排放量的42.5%、29.7%、24.9%和2.9%。利用臭氧生成潜势和二次有机气溶胶生成潜势评估VOCs的大气活性，发现DPF再生过程中增加的VOCs对环境有显著影响。增加的VOCs生成的臭氧和二次有机气溶胶分别为4272.8μg·m和9.0μg·m。芳烃和烷烃对臭氧和二次有机气溶胶的贡献最为显著。因此，应考虑DPF再生对柴油发动机VOCs排放的影响。经计算，DPF再生的VOCs排放因子为1.03mg·(kW·h)，可为国Ⅵ柴油车VOCs排放因子的制定提供参考。
