Predicting the Kinematic Viscosity of Biodiesel at Various Temperatures from its Saponification Number and Iodine Value

Abstract

The kinematic viscosity of biodiesel is significantly influenced by the chemical composition of its fatty acid methyl ester. In this work, correlation that can be used to predict the kinematic viscosity of pure biodiesel and blended biodiesel as a function of the saponification number, iodine value and temperature was developed. Data available in literature were used to validate the correlation and to support speculations arisen from the proposed equation. The proposed correlation is easy to use and the predicted kinematic
viscosity values of both pure biodiesel and blended biodiesel at different temperatures agree well with the literature values. The estimated kinematic viscosity values of pure biodiesel and mixed biodiesel are in good agreement with those 212 data reported in the literature within a temperature range of 20-100ºC; the average absolute deviation is 6.91%. The kinematic viscosity value outside of this temperature range may be possibly predicted by the correlation but the accuracy may be lower.