Investigation of the physical and chemical stability of biodiesel produced from Jatropha Curcas Species in Zimbabwe

Abstract

Jatropha curcas L. seeds as a raw material for biodiesel production are a rapidly growing interest over the world because of their high oil content, ecological adaptability, and excellent fuel properties. Though there is an increase in productivity of biodiesel, showing solution for future energy insecurity, there still remains some concern for commercialization due to its susceptibility to degradation during long term storage. The aim of this research work is to investigate the effect of temperature and ambient condition on Jatropha biodiesel storage. A study was conducted for a period of 12 months, where Jatropha biodiesel samples were stored at different temperatures (4°C, 25°C, and 35°C) and environmental conditions (darkness, light, and air). At regular intervals, the samples were taken out to analyze acid value, density, kinematic viscosity, and fatty acid profile to monitor the quality of biodiesel. Analysis showed that acid value, density, kinematic viscosity, and fatty acid content increases with the increase in storage time of biodiesel samples. However, Jatropha biodiesel stored at 35°C, in contact with ambient air and light showed highest degradation compared to that which was stored at 25°C and 4°C. Among all the parameters studied, high temperature and air exposure are the two most important parameters which accelerate the degradation process. Light exposure had mild but significant effect on Jatropha biodiesel degradation over a long storage period.