Analysis of Unregulated Emissions from a Diesel Bus Equipped with CDPF
In this paper, it was studied on effects of CDPF (catalyzed diesel particulate filters, (DPF) on the unregulated emissions, volatile organic compounds (VOCs), particulate carbon components, particulate polycyclic aromatic hydrocarbons (PAHs) and its toxicity from the diesel bus emissions. The results show that the VOCs were reduced by 57.6% by the CDPF, the total carbon (TC) were reduced by 70.4%. The PAHs from diesel bus were reduced up to 91.1% and the CDPF showed higher reduction rate for low-ring PAHs, such as 3-ring and 4-ring PAHs, while it presented lower selective for higher ring PAHs. The CDPF can obviously reduce the toxicity equivalent of different benzene ring PAHs, and there was no obvious effect on toxicity equivalent ratio of different benzene rings of PAHs 柴油公交车加装CDPF的非常规污染物排放特征分析 冯谦,李菁元,王计广,徐月云,秦孔建,李孟良 中国汽车技术研究中心,天津 300300 关键词:非常规排放物,CDPF,柴油公交车,测试技术。 摘要:本文测试分析了柴油公交车安装CDPF(catalyzed diesel particulate filters, CDPF)在瞬 态测试循环工况下对非常规气态物、颗粒物中的碳质组分、芳香烃及其毒性的影响,研究结 果表明:CDPF对挥发性有机物VOCs(volatile organic compounds,VOCs)的减排率为57.6% ,对柴油车颗粒物中总碳TC减排率为70.4%,对柴油车颗粒中PAHs(polycyclic aromatic hydrocarbons, PAHs)组分减排率为91.1%,CDPF对低环数的PAHs表现较高的减排率,而对 其他环数的PAHs的减排率略低。CDPF能明显降低不同苯环PAHs的毒性当量,但对不同苯 环PAHs的毒性当量比例影响不明显。 前言 由北京、上海等大城市的大气细颗粒物来源解析分析,其主要来源既有来自污染源直接排放的一次颗 粒物,也有由污染源排放的气态污染物通过均相和非均相等复杂的大气化学反应而生成二次无机/有机颗 粒物[1-2],这些气态污染物称为二次颗粒气态前体物。一次颗粒物与污染排放源直接相关,而二次颗粒物 不仅受到污染源排放二次颗粒气态前体物的影响,而且天气条件和大气化学反应过程对二次颗粒的形成 起着重要的决定作用[3],大气中光化学水平增强,二次颗粒物的生成量呈数倍增加,直接造成大气中颗粒 物浓度增加[4]。大气环境化学相关研究表明,污染源排向大气中的挥发性有机物VOCs(Volatile organic compounds)、一氧化碳CO、氮氧化物NOX、硫化物SOX等是大气中形成二次颗粒物的重要气态前体物, 对大气中颗粒物的形成和雾霾污染有直接作用。 DPF(Diesel Particulate Filter)是降低柴油机的颗粒物排放最有效的后处理技术,主要通过多孔介质载体 对颗粒物进行捕集,捕集效率达90%以上。近些年,为了加强DPF的催化氧化能力以及实现再生,通过在 DPF载体表面涂覆催化剂,即催化型DPF(Catalyzed DPF, CDPF),一方面,涂覆的催化剂可以将柴油机