Abstract

In this study, the density, viscosity, cloud and pour points of shea butter biodiesel-diesel fuel blends were measured following ASTM test methods. In order to predict these properties, mixing rule was evaluated as a function of the volume fraction of biodiesel in the blend. The effects of biodiesel fraction on each of these properties in addition to the effects of temperature on density and viscosity were investigated. The blends (B2, B5, B10, B20, B50 and B75) were prepared on a volume basis. Generalized equations and Arrhenius equation for predicting the density and viscosity of the blends were used. The low values of the absolute average deviations (AAD) and the maximum absolute deviations (MAD) obtained confirmed the suitability of the mixing rule used. For all the blends, it was observed that the results from the measured and estimated values of density and viscosities were in good agreement. From the results, the density and viscosities of the blends decreased with increase in temperature while these properties increased with increase of biodiesel content in the fuel blend. The cloud point and the pour point of the blend increased as the biodiesel concentration increases. The values obtained from empirical equations for predicting the relationship between cloud point, pour point and biodiesel content in the blends were in good agreement with the experiments.

Key words: Shea butter biodiesel, blend, diesel, flow properties.