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排序方式: 共有412条查询结果,搜索用时 31 毫秒
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车用柴油机排气中的微粒是一种十分有害的大气污染物,如何有效地净化它一直是人们密切关注的课题。介绍了一种旋流分离净化技术,以及应用此技术首先应解决的问题。 相似文献
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In this work, the airborne particulate matter with an aerodynamic diameter less than 10 µm (PM10) was fractionated in a six-stage high-volume cascade impactor to identify particulate size distribution in Tehran atmosphere. The study was conducted at 15 sites located in the north, south, east, west, and central parts of Tehran in 2005. Air samples were analyzed for 16 polycyclic aromatic hydrocarbons (PAHs) by HPLC. The daily PM10 concentrations at the peak of traffic in roadside areas were found to be 106–560 µg m?3. The cumulated concentration sum of PAHs, based on 16 species, was found to have an average concentration of 380 ng m?3. Furthermore, it was found that more than 60% of PAHs belonged to the small particulate size range, having sizes of less than 0.49 µm, some containing benzo(ghi)perylene and indeno(123cd)pyrene (high molecular weight) with average concentrations of 8 and 6 ng m?3 and fluorene, phenanthrene, and fluoranthene (low molecular weight) with average concentrations of 14, 13, and 19 ng m?3, respectively. In addition, the results revealed that the lighter three- and four-ring PAH compounds were the most abundant pollutants in the air collected at all the sampling sites. 相似文献
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Loretta Müller Pierre Comte Jan Czerwinski Markus Kasper Andreas C.R. Mayer Adrian Schmid 《毒物与环境化学》2013,95(1):164-180
The aim of this study was to compare the cytotoxicity and the (pro-)inflammatory responses of two-stroke (direct injection and carburetor technology) and four-stroke scooter and diesel car exhaust emissions on lung cells in vitro. This was analyzed by exposing a 3D in vitro model of the epithelial airway (consisting of human bronchial epithelial cells (cell line 16HBE14o?) combined with human whole blood monocyte-derived macrophages and dendritic cells) to physically characterized exhaust emissions. Biological endpoints of cytotoxicity (lactate dehydrogenase release), as well as pro-inflammatory cytokine (tumor necrosis factor (TNF)-α) and inflammatory chemokine (interleukin(IL)-8) stimulation were examined. Two-stroke direct injection scooter exhaust contained the highest particle number concentration and nitrogen oxides (NO x ) concentrations and the emissions from the two-stroke carburetor scooter contained the highest hydrocarbon and lowest NO x concentrations. The four-stroke scooter emitted the highest carbon monoxide concentration whereas the cars emitted the lowest. The combination of various technical optimizations for the two-stroke direct injection scooter (particle filter, oxidative catalyst, better oil and fuel) reduced the total emissions strongly and the TNF-α concentration significantly (p?0.05). The cytotoxicity and the IL-8 concentration showed strong tendencies to be reduced. The analysis of the emissions of all tested two-stroke, four-stroke scooters and diesel cars showed a strong association between the adverse effects and the particle number concentration. 相似文献
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针对一台轻型柴油机,采用国Ⅳ柴油,在不使用和使用后处理装置的条件下,进行ESC循环工况(分别记为ESC-0、ESC-DP)和ETC循环工况(分别记为ETC-0、ETC-DP)下的发动机台架测试.每次测试用一对滤膜采集颗粒物,采样前后分别称重以确定颗粒物质量,进而计算排放因子.用气相色谱-质谱联机(GC-MS)分别分析每张滤膜上颗粒物的多环芳烃(PAHs)组分.ESC-0、ESC-DP、ETC-0、ETC-DP的颗粒物排放因子分别为0.12,0.05,0.48,0.16 g/(kW·h);相应的PAHs排放因子分别为69,35,174,76 μg/(kW·h).后处理分别使颗粒物和PAHs减排56%~68%和49%~56%.总PAHs中,三环PAHs占比重最大(64%±9%).PHE在总PAHs中占比重最大(54%±9%).PAHs的分布与其物理化学特性、柴油中的芳烃含量有关.PAHs特征比值FA/(FA+PY)为0.37~0.51. 相似文献
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三辆柴油公交车分别安装柴油机氧化催化器(DOC),催化型颗粒捕集器(CDPF)与DOC+CDPF三种后处理装置,采用便携式排放测试系统PEMS进行测试,研究整车THC,CO与NOx等气态物排放性能随行驶里程的变化规律.研究结果表明:对于加装了DOC的公交车,行驶里程达到8万km时DOC性能劣化,应进行保养,此前CO,THC与NOx的平均转化效率分别为78%,43%和27%;CDPF有效工作时间短,需要定期进行高温保养,周期应为1万km左右,加装CDPF的公交车CO,THC与NOx平均转化效率分别为74%,16%与15%;DOC+CDPF在行驶里程达12万km时才出现性能劣化现象,此前加装该后处理装置后的公交车CO,THC与NOx平均转化效率分别为87%,76%与21%.DOC+CDPF的连续再生效果可有效延长后处理装置的工作寿命. 相似文献
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DOC+CDPF配方对柴油公交车颗粒物排放特性影响 总被引:1,自引:0,他引:1
为研究不同DOC+CDPF(催化型连续再生颗粒捕集器)配方对公交车颗粒物排放特性的影响,以一辆满足国Ⅲ排放的柴油公交车为试验样车,在重型底盘测功机上分别进行了加装3种不同DOC+CDPF的柴油机在中国典型城市公交车循环(CCBC)中的排放特性试验,分析了不同贵金属负载量对柴油机颗粒物排放特性的影响.结果表明:在相同贵金属配比情况下,当DOC+CDPF催化剂配方中贵金属负载量较高时,颗粒物浓度降幅较大.3种方案的颗粒物质量浓度综合减排率分别为99.3%、98.8%、96.4%,平均降幅达到98.2%;当使用DOC+CDPF后,柴油机颗粒物粒径分布由双峰对数分布变为三峰对数分布,但不同催化剂配方下对应的粒径最大峰值点会偏移;采用DOC+CDPF装置后,发动机排放背压略有增加.且当贵金属负载量越高时,装置压降增量越少,被动再生性能越优异. 相似文献
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