连续再生颗粒捕集器对燃用生物柴油的柴油机颗粒物以及多环芳香烃的影响研究

Study of the Effect of Continuously Regenerating Particulate Trap System on Particle and PAHs Emissions from an Turbocharged Biodiesel Engine

为探究降低柴油机微粒及多环芳香烃的有效排放控制措施,在一台燃用生物柴油的增压多缸柴油机上应用连续再生微粒捕集器系统,研究了柴油机燃用生物柴油及采用连续再生微粒捕集器系统后对柴油机微粒和多环芳香烃排放的影响。研究结果显示:柴油机微粒排放呈现核态与聚集态形式并且粒子粒径呈现多峰值化特征,燃用生物柴油对核态微粒粒径浓度影响不大,而聚集态微粒排放则有着较为明显的下降趋势,采用连续再生颗粒捕集器后最大下降幅度达到94.6%。柴油机微粒排放中核态粒子浓度占60%以上,燃用生物柴油后该值进一步提升,在试验工况下最大可达到95%。连续可再生微粒捕集器对聚集态粒子捕集效率高,最高可达到96%,试验用柴油机使用生物柴油后,由于核态颗粒数量浓度的提升致使捕集器系统效率有所下降。燃用生物柴油可有效降低绝大部分的多环芳香烃的排放,但测试结果显示:和苯芘蒽排放不降反升,与连续可再生微粒捕集器系统结合,能让菲、芘、苯芘等6种物质排放下降幅度更大。

In order to reduce the particulate and polycyclic aromatic hydrocarbon emissions, the effect of biodiesel and particulate trap on particle and polycyclic aromatic hydrocarbons emissions was studied on a multi-cylinder turbocharged biodiesel engine with continuous exhaust regeneration. Results show that the diesel particle emissions present in two forms namely nucleation mode and aggregation mode and its particle sige has a multi peak feature. Using biodiesel has little effect on the nucleation mode particle number concentration, but can make the aggregation mode particle emissions have a clear downward trend with the biggest drop up to 94. 6~ after using a continuously regenerating particulate trap system. The nucleation mode particle number concentration in diesel particle emissions accounts for more than 60~, and can be further increased up to 95% after burning biodiesel at the test conditions. The continuously regenerating particulate trap system has a higher collection efficiency for aggregation mode particles with, the maximum efficiency of 96%, which will be decreased after burning biodiesel, due to the increased nucleation mode particle number concentration clsing biodiesel can effectively reduce most of polycyclic aromatic hydrocarbons emissions, but test results show that chrysene can not he reduced hut increased. The joint use of biodiesel and continuously regenerating particulate trap system can make the phenanthrene, pyrene and benzopyrene etc, six kinds of exhaust pollutants fell even more.