Antioxidants for improving storage stability of biodiesel

Abstract

Biodiesel is an alternative diesel fuel made from vegetable oil or animal fat that may be burned in a compression-ignition (diesel) engine. The chemical nature of biodiesel makes it more susceptible to oxidation or autoxidation during long-term storage than conventional petroleum-based diesel (petrodiesel). Oxidative degradation during storage can compromise fuel quality with respect to effects on kinematic viscosity, acid value (number), cetane number, total ester content, and formation of hydroperoxides, soluble polymers, and other secondary products. One promising method of increasing the resistance to oxidation of biodiesel is to add oxidation inhibitors (antioxidants). This review summarizes relevant research progress in the development of effective antioxidants for treating biodiesel. Performance of antioxidants evaluated for treating biodiesel derived from soybean oil, rapeseed (low-erucic) oil, used cooking oil, tallow (beef), and palm oil feedstocks is discussed.