国Ⅳ柴油机颗粒物与颗粒态多环芳烃排放特征

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.

Paticulate matter and particle-phase PAHs emission characteristics of the China IV diesel engine

Particulate matter (PM) and particle-phase polycyclic aromatic hydrocarbons (p-PAHs) emission characteristics were studied using a China IV diesel engine equipped with Diesel Oxidation Catalyst + Particulate Oxidation Catalyst emission control device (DOC+POC) fueled with China IV diesel. The engine was tested with an engine dynamometer four times:during ESC cycle without and with emission control device, during ETC cycle without and with emission control device (marked as ESC-0, ESC-DP, ETC-0 and ETC-DP, respectively). PM was sampled using a pair of Pallflex Emfab filters, which were weighed before and after sampling to calculate the mass of PM. PAHs in PM were measured by Gas Chromatography-mass Spectrometry (GC-MS). For ESC-0, ESC-DP, ETC-0 and ETC-DP, PM emission factors were 0.12, 0.05, 0.48 and 0.16g/(kW·h), respectively, and p-PAHs emission factors were 69, 35, 174 and 76 μg/(kW·h), respectively. With emission control device, PM emissions were reduced by 56%~68%, and PAHs emissions were reduced by 49%~56%. In total p-PAHs mass, three-ring PAHs accounted for 64%±9%, and PHE accounted for 54%±9%. The distribution of PAHs was influenced by physicochemical characteristics of PAHs and PAHs contents in diesel. The FA/(FA+PY) ratios were 0.37~0.51.