提高柴油/甲醇组合燃烧尾气排放质量的研究

Study on emission characteristics of diesel/methanol compound combustion

对原机、柴油/甲醇组合燃烧,以及带氧化催化转化器的柴油/甲醇组合燃烧3种情况下的尾气排放进行了比较和研究.针对柴油/甲醇组合燃烧可以使NOx、烟度大幅度下降,但同时PM、CO和HC的排放浓度与原机相比反而增加的现状,通过加装氧化催化转化器,对废气进行处理后,发现HC、CO和PM排放明显减少.与原机相比,不仅可以实现大幅度降低NOx,而且PM排放也有较大幅度下降.采用透射电子显微镜观察发现,与原机相比,柴油/甲醇组合燃烧的PM排放中干炭烟(DS)减少,但是可溶有机物(SOF)增加.经过氧化催化转化器处理后,尾气的PM中大量SOF和HC化合物被消除,致使PM的质量明显减少.

In this paper, emissions of three kinds of combustion mode, which is diesel engine, dieseL/methanol compound combustion （DMCC） , as well DMCC with an oxidation catalytic converter respectively, are compared and analyzed. The experimental results showed that NOx of DMCC mode reduced remarkably compared to diesel engine, while PM, CO and HC were increased. With an oxidation catalytic converter, HC, CO and PM from DMCC engine were obviously decreased. In this case, both NOx and PM from the engine were much lower than those from diesel engine at the same time. Meanwhile, the PM was observed carefully with a transmission electron microscope （TEM）. With this one it was found that the dry soot in PM was reduced but SOF was increased in DMCC mode. The experimental results illustrated that the weight of PM remarkably reduced with oxidation catalytic converter because of a lot of SOF and HC in PM eliminated by oxidation catalytic converter.