National Lab of Auto Performance and Emission Test, School of Mechanical and Vehicular Engineering, Beijing Institute of Technology, Beijing 100081, China.
J Environ Sci (China). 2012;24(4):624-31. doi: 10.1016/s1001-0742(11)60810-3.
Two continuously regenerating diesel particulate filter (CRDPF) with different configurations and one particles oxidation catalyst (POC) were employed to perform experiments in a controlled laboratory setting to evaluate their effects on NO2, smoke and particle number emissions. The results showed that the application of the after-treatments increased the emission ratios of NO2/NOx significantly. The results of smoke emissions and particle number (PN) emissions indicated that both CRDPFs had sufficient capacity to remove more than 90% of total particulate matter (PM) and more than 97% of solid particles. However, the POC was able to remove the organic components of total PM, and only partially to remove the carbonaceous particles with size less than 30 nm. The negligible effects of POC on larger particles were observed due to its honeycomb structure leads to an inadequate residence time to oxidize the solid particles or trap them. The particles removal efficiencies of CRDPFs had high degree of correlations with the emission ratio of NO2/NOx. The PN emission results from two CRDPFs indicated that more NO2 generating in diesel oxidation catalyst section could obtain the higher removal efficiency of solid particles. However this also increased the risk of NO2 exposure in atmosphere.
采用两种不同结构的连续再生式柴油机微粒捕集器（CRDPF）和一种微粒氧化催化剂（POC），在可控的实验室条件下进行试验，以评估它们对 NO2、烟尘和颗粒数排放的影响。结果表明，后处理的应用显著增加了 NO2/NOx 的排放比。烟尘和颗粒数（PN）排放的结果表明，两种 CRDPF 都有足够的能力去除超过 90%的总颗粒物（PM）和超过 97%的固体颗粒。然而，POC 只能去除总 PM 的有机成分，而对小于 30nm 的碳质颗粒只能部分去除。由于 POC 的蜂窝状结构导致固体颗粒的氧化或捕获的停留时间不足，因此对较大颗粒的影响可以忽略不计。CRDPF 的颗粒去除效率与 NO2/NOx 的排放比高度相关。来自两个 CRDPF 的 PN 排放结果表明，在柴油机氧化催化剂段产生更多的 NO2 可以获得更高的固体颗粒去除效率。然而，这也增加了大气中 NO2 暴露的风险。
