Synergistic effects of alcohol-based renewable fuels: fuel properties and emissions

[摘要] Biodiesel is known to improve the fuel properties of alcohol-diesel blends. However biodiesel is obtained from different feedstock and consequently the composition can be different, with varying fatty acid profiles resulting in different physical and chemical properties and a different response when blended with alcohol-diesel blends. To understand the effect of molecular structure of biodiesel on fuel properties and emissions, the most representative individual fatty acid methyl esters were added to alcohol-diesel blends. The results show that 15% of all methyl esters was enough to avoid phase separation of alcohol-diesel blends and keep the wear scar diameter of the blends below the limitation required by lubricity standards. Short carbon chain length and saturated methyl ester are recommended to improve emissions of alcohol-diesel blends. A comparison between two different alcohols used in the engine tests highlighted that butanol blends were more effective in reducing carbonaceous gas emissions and particulate matter emissions than ethanol blends. Further research on the effect of molecular structure of biodiesel on alcohol-diesel blends was conducted to understand influence of hydroxylated biodiesel which is derived from castor oil. The existence of hydroxyl group in biodiesel considerably improves the lubricity of alcohol-diesel blends. It was also shown to be beneficial in terms of engine-out emissions such as enhancing soot oxidation and reducing activation energy to oxidise soot emissions. To counteract the likely increase in gaseous carbonaceous emissions with alcohol blends, the addition of hydrogen to replace part of the carbon within the liquid fuel was studied. The incorporation of hydrogen and alcohol blends indicates that there was a dramatic reduction in carbon dioxide, unburnt hydrocarbons and particulate matter emissions.

[发布机构] University:University of Birmingham;Department:School of Engineering, Department of Mechanical Engineering

[关键词] T Technology;TA Engineering (General). Civil engineering (General)