柴油机燃用不同燃料颗粒微观形貌与氧化特性分析

Analysis on Micro-Morphology and Oxidation Characteristics of Particles for Diesel Engine Fueled with Different Fuels

为研究柴油机燃用不同替代燃料排气颗粒的微观形貌和氧化特性,通过柴油机台架试验,采集了生物柴油、F-T柴油、0号柴油的排气颗粒,运用透射电镜、热重分析仪对3种燃料燃烧产生的颗粒进行研究。结果表明:燃用生物柴油、F-T柴油的颗粒粒径均小于0号柴油颗粒,生物柴油、F-T柴油、0号柴油颗粒的平均粒径分别为23.65 nm,19.32 nm,26.47 nm;生物柴油、F-T柴油、0号柴油颗粒的计盒维数分别为2.0139,1.9675,1.9902,生物柴油颗粒的计盒维数最大,颗粒堆叠严重;生物柴油、F-T柴油、0号柴油的可溶有机物含量分别为23.4%,12.7%,17.6%,炭烟含量依次为73.4%,84.6%,79.5%。氧化特性的分析结果表明:与0号柴油相比,生物柴油颗粒的起燃温度、燃尽温度和活化能更小,F-T柴油的氧化特性参数更大,表明生物柴油颗粒更易被氧化,而F-T柴油颗粒不易被氧化。

In order to study the micromorphology and oxidation characteristics of exhaust particles for diesel engine fueled with different alternative fuels,exhaust particles of biodiesel,FT diesel and 0#diesel were collected through diesel engine bench test.The particles of those fuels were analyzed by means of transmission electron microscopy(TEM)and thermogravimetric analyzer.The results showed that the particle size of biodiesel and FT diesel was smaller than that of 0#diesel.The average particle size of biodiesel,F-T diesel and 0#diesel was 23.65 nm,19.32 nm and 26.47 nm and each corresponding boxcounting dimension was 2.0139,1.9675 and 1.9902 respectively.The biodiesel particle boxcounting dimension was the largest and so the particle stack was serious.The soluble organic matter content of biodiesel,F-T diesel and 0#diesel was 23.4%,12.7%and 17.6%and each corresponding soot content was 73.4%,84.6%and 79.5%respectively.The analysis results of oxidation characteristics show that the ignition temperature,burnout temperature and activation energy of biodiesel particles are smaller and the oxidation characteristic parameters of F-T diesel are larger compared with 0#diesel,indicating that the order of oxidation from easy to difficult is biodiesel,0#diesel and F-T diesel.