Characterization of residual fuel compositions and the effect on the ignition and combustion performance
Quality of marine fuels has changed for the last 10 years, and it is well known that they have been getting heavier and lower in viscosity resulting in poorer combustion quality. This is caused by recent advancement of oil refining process, economic trend and increasing needs for light distillates, and environmental regulations. Ignition and combustion performance are affected by various factors including the characteristics of the fuel, engine design, operational conditions and settings of the engine, applied load, and ambient conditions. Residual fuels are mixture products consisting of vacuum residue (VR) and some intermediate products of oil refinery process. Thus, to analyze the blending process and characteristic of the residual fuels may lead to better understandings of the combustion process in diesel engines and taking countermeasure against possible engine damages. In this study, the effect of chemical composition of residual fuels on its ignition and combustion quality was investigated. The blend compositions were estimated by thermal and chemical analyses and discussed with the results of combustion characteristics. The sample fuels were blended with different proportions of a straight-run light gas oil (LGO), a vacuum gas oil (VGO), a FCC light cycle oil (LCO), a FCC clarified oil (CLO) and a VR. These blending components and sample fuels were also used to know the quality control of the commercial marine fuel oils. The chemical compositions of these fuels were analysed by using thermogravimetry (TG) and gas chromatography / mass spectroscopy (GC/MS). The TG analysis in a nitrogen gas flow and GC/MS gives a distillation curve of fuels and a detailed composition profile of the lower-boiling components, respectively. Their ignition and combustion analysis was also carried out by using Fuel Combustion Analyzer. According to the GC/MS, LCO and CLO were characterized by mainly 2-ring (especially methyl-, dimethyl- and ethyl- naphthalenes) and 4-ring polycyclic aromatic hydrocarbons (methyl- and dimethyl-pyrenes), respectively. The results suggest that the fuel ignition quality is significantly affected by the amounts of both 2-ring polycyclic aromatic hydrocarbons and relatively lower molecular weight alkane series (C14-C18), which are interpreted as the amounts of LCO and LGO. Some of the commercial marine fuel oils were found to be ’gap-fuels’, which were estimated to containing only LCO and VR. They exhibited a very low Estimated Cetane Number (ECN), almost the same as that of pure LCO, and can potentially result in serious engine damages.
Chiori Takahashi Shoko Imai Yoshitaka Yamaguchi Tetsuya Senda
National Maritime Research Institute,JAPAN
国际会议
上海
英文
1-12
2013-05-13（万方平台首次上网日期，不代表论文的发表时间）