摘要
为探讨柴油机燃用正丁醇-柴油混合燃料降低颗粒排放的机理,采用热重分析仪与场发射扫描电子显微镜,重点对正丁醇-柴油混合燃料燃烧的颗粒形貌特征进行研究,分析了颗粒的组分、微观结构以及粒径分布随w(正丁醇)的变化规律.结果表明:正丁醇-柴油混合燃料燃烧的颗粒呈团簇状结构,随着w(正丁醇)的增加,团聚程度逐渐提高,排列结构更加紧密;颗粒的粒径逐渐减小,柴油、B5、B10〔B5、B10是指w(正丁醇)分别为5%、10%的正丁醇-柴油混合燃料〕燃烧的颗粒平均粒径分别为1.43、0.85、0.52μm;颗粒中的主要成分为碳烟,其质量分数约为60%,随着w(正丁醇)的增加,碳烟和可溶有机物组分的质量分数有所增加,硫酸盐、金属等不易挥发组分以及金属元素的质量分数逐渐减少.研究显示,添加正丁醇,可促进颗粒转化、改善颗粒的氧化过程,使颗粒向小粒径方向移动;由于颗粒中可溶有机物组分含量增加,因此提高了颗粒在碰撞过程中凝并的概率,致使颗粒的团聚程度增加.
In order to investigate why particle emissions are reduced when butanol-diesel fuel is burned in diesel engines, the characteristics of particles emitted from burning different butanol-diesel blends in diesel engines were systematically studied to analyze the principles of composition,size distribution and microstructure of the particles using thermal analysis and field emission scanning electron microscope technology. The butanol was added into the blend with three kinds of mass percentages： 0（ B0）,5%（ B5）,10%（ B10）. It was observed that particles of different butanol-diesel blends all demonstrated cluster structures,and they became more compacted with the rising butanol percentage. In addition,the aggregation degree was larger. Moreover,the particle size decreased with the improvement of butanol percentage; the sizes were 1. 43,0. 85 and 0. 52 μm with butanol-diesel blends of B0,B5 and B10. The main component of the particles was soot,which accounted for approximately 60% of the total particle mass. With the increase of butanol ratios,the proportions of soluble organic fraction（ SOF） and soot were increased,while sulfates,metals and other non-volatile components decreased gradually.The results showed that particle transformation was stimulated,and the oxidation process was substantially improved,with the addition of butanol. Plus,the size distribution of particles was smaller figure than with no butanol added. The proportion of SOF on the surface of the particles was increased,which increased the coagulation probability in collision situations among particles; the particle size decreased and agglomeration was improved as a result.
出处
《环境科学研究》
EI
CAS
CSSCI
CSCD
北大核心
2015年第10期1518-1523,共6页
Research of Environmental Sciences
基金
国家自然科学基金项目(51376083)
江苏省普通高校研究生科研创新计划项目(CXZZ13_0672
KYLX_1035)
关键词
正丁醇
柴油
颗粒
状态特征
组分
butanol
diesel
particle
characteristic state
component
