Comparative study on the effects of oxygenate on biodiesel from fresh and used cooking oil.

Abstract

Biodiesel is a renewable fuel that will soon be fully accepted in the commercial world but there are limitations to its use that need improvement. The use of oxygenated additives have improved the burning/fuel qualities of conventional diesel and gasoline. These oxygenates may also improve the qualities of biodiesel. This paper focuses on comparing the fuel qualities such as the density, specific gravity, heat content, flash point, and kinematic viscosity of oxygenate-biodiesel blends. The biodiesel was produced from fresh and waste cooking oil and they were characterized and compared to ASTM standards. The oxygenated additives (ethanol, methanol and diethyl ether) were blended in the percentages 10, 20, 30 and 40% with biodiesel from fresh and waste oil. The physicochemical properties such as kinematic viscosity, density, specific gravity, flash point and heat content were analyzed for the blends. The density and specific gravity values were within the range of 0.74-0.84 g/ml and 0.76-0.85 respectively. The kinematic viscosities at 40oC were within 3.5-5.0 mm2 s -1 after oxygenated additives were added. The blends ignited at 16oC before the flashpoints could be gotten. The heat content values for the biodiesel from fresh oil increased at 10 and 20% but decreased at 40% while that of biodiesel from waste oil decreased at 10, 30, and 40% for the ethanol and methanol blends. The diethayl ether blends did not show any pattern with increase in addition. The oxygenate addition improved the density, specific gravity, and kinematic viscosity. Oxygenate addition may be a good way of improving the properties of biodiesel as shown in the project.