Evaluation of properties and storage stability of Madhuca indica biodiesel

Mahua Oil (MO) is an underutilized non-edible vegetable oil, which is available in large quantities in India. In the present work, biodiesel was derived from the MO by the transesterification process. The fuel properties of the MO biodiesel were found to be within the limits of biodiesel specifications of many countries. The chemical nature of biodiesel makes it more susceptible to oxidation during long-term storage which leads to degradation of fuel properties that can compromise fuel quality. The effect of long storage condition on the stability of the MO biodiesel was studied in the present work. The biodiesel samples were stored in plastic containers at room temperature. The study was conducted for a period of 12 months and the test sample was kept in the darkness. From the experimental results, it was observed that the acid value and viscosity increases with the storage time, but the iodine value decreased with increasing storage time. This is due to the presence of the double bond in the molecule of the biodiesel which produce a high level of reactivity. This high level reactivity produces formation of hydroperoxides, soluble polymers and other secondary products. From the experimental results, a slight difference in the acid value, iodine value and viscosity of the MO biodiesel stored for a period of 30 days was observed. But after this period, the differences were significant.