Lou Di-Ming, Zhang Zi-Jun, Liu Ji-Yue, Tan Pi-Qiang, Hu Zhi-Yuan
School of Automotive Studies, Tongji University, Shanghai 201804, China.
Huan Jing Ke Xue. 2017 Dec 8;38(12):4983-4990. doi: 10.13227/j.hjkx.201706059.
Based on heavy chassis dynamometers, an experimental study was conducted in a diesel bus with proton transfer reaction mass spectrometry (PTR-MS). It investigated the effects of volatile organic compound (VOC) emission characteristics with three different diesel oxidation catalyst (DOC)+catalyzed diesel particulate filter (CDPF) after-treatments for a typical Chinese city bus driving cycle (CCBC). The results reveal that the major compounds from the diesel bus are OVOCs, aromatic hydrocarbons, alkenes, alkanes, nitrogenous organic compounds, and polycyclic aromatic hydrocarbons (PAH), and that the OVOCs account for more than 50%of the total VOCs. With the same precious metal composition and ratio of the proportion in the CDPF catalyst, the emissions of VOCs decrease with an increase in precious metal load. The emission reduction rates of the VOCs are 36.2%, 40.1%, and 41.4%, respectively, when the precious metal loads are 15 g·ft (type A after-treatment device), 25 g·ft (type B), and 35 g·ft (type C). The average emission rates of alkanes for the three kinds of DOC+CDPF after-treatments are all over 59% for the entire CCBC cycle. The type C after-treatment device can reduce the alkane emissions by 70.2%, with a slight advantage for the OVOC reduction compared with type A and type B devices. For unsaturated hydrocarbons, including aromatic hydrocarbons, alkenes, and PAHs, the after-treatment devices have a catalytic effect, but there is no significant difference between them. The emissions of nitrogenous organic compounds are greatly decreased, by 50.5%, with the type A after-treatment, but the reduction rate decreases with an increase in precious metal load. In addition, OVOCs, aromatic hydrocarbons, and alkenes are the most important contributors to ozone formation. The adoption of DOC+CDPF reduces the emissions of VOCs and, therefore, the ozone formation potential. Taking into account the emission reduction rates and costs of the three different after-treatments and for weighting coefficients of 0.8 and 0.2, respectively, the type B after-treatment is the optimal solution.
基于重型底盘测功机，使用质子转移反应质谱法（PTR-MS）在一辆柴油公交车上进行了一项实验研究。该研究针对典型的中国城市公交车行驶循环（CCBC），考察了三种不同的柴油氧化催化剂（DOC）+催化型柴油颗粒过滤器（CDPF）后处理方式对挥发性有机化合物（VOC）排放特性的影响。结果表明，柴油公交车排放的主要化合物为含氧挥发性有机化合物（OVOCs）、芳烃、烯烃、烷烃、含氮有机化合物和多环芳烃（PAH），其中OVOCs占总VOCs的比例超过50%。在CDPF催化剂中贵金属成分及比例相同的情况下，VOCs排放量随贵金属负载量的增加而降低。当贵金属负载量分别为15 g·ft（A型后处理装置）、25 g·ft（B型）和35 g·ft（C型）时，VOCs的减排率分别为36.2%、40.1%和41.4%。在整个CCBC循环中，三种DOC+CDPF后处理方式下烷烃的平均排放率均超过59%。C型后处理装置可使烷烃排放量降低70.2%，与A型和B型装置相比，在减少OVOCs方面略有优势。对于包括芳烃、烯烃和PAH在内的不饱和烃，后处理装置具有催化作用，但它们之间没有显著差异。含氮有机化合物的排放量通过A型后处理大幅降低了50.5%，但减排率随贵金属负载量的增加而降低。此外，OVOCs、芳烃和烯烃是臭氧形成的最重要贡献者。采用DOC+CDPF可降低VOCs排放，从而降低臭氧生成潜力。综合考虑三种不同后处理方式的减排率和成本，以及加权系数分别为0.8和0.2的情况，B型后处理是最佳解决方案。
