Effect of Temperature on the Oil Stability Index (OSI) of Biodiesel

Abstract

Biodiesel, an alternative fuel derived from lipid feedstocks, such as vegetable oil or animal fat, is mainly composed of saturated and unsaturated fatty acid alkyl esters. Fuel suppliers, terminal operators, and users are becoming more concerned with monitoring and maintaining good biodiesel fuel quality with respect to oxidative degradation during storage. The oil stability index (OSI), a parameter that measures the relative oxidative stability of fatty materials, is typically measured isothermally at elevated temperatures to accelerate oxidation. The present work investigates the effects of block temperature (T) on the OSI of biodiesel from soybean oil fatty acid methyl esters (SME) and used cooking oil fatty acid methyl esters (UCOME). Results were compared to those for pure methyl oleate (MO). An increasing temperature accelerated the oxidation reaction causing a decrease in OSI. Response factors (RF) determined with MO as the reference methyl ester showed little variation with respect to the temperat...