Corrosion behavior of biodiesel from seed oils of Indian origin on diesel engine parts

Environmental factors and depleting reserves of crude oil are becoming the main driving force in the quest for cleaner and alternate fuels. In India, adoption of Euro III and Euro IV equivalent emission norms are under consideration. The Euro III emission norms have already been implemented in 7 mega cities and would be implemented in the rest of the country by the year 2010. This will lead to drastic reduction in sulphur content and increase in cetane number, which in turn will adversely affect the lubricity characteristics of the diesel fuel. However, the use of biodiesel will improve the lubricity and cetane number requirements particularly for ultra low sulphur diesel. Studies for the synthesis and characterization of biodiesel from non-edible oils like Jatropha curcas, Pongamia glabra (Karanja), Madhuca indica (Mahua) and Salvadora oleoides (Pilu) have already been carried out in our laborotary. Corrosion characteristics of biodiesel are important for long term durability of engine parts, and very little information is available on this aspect. The studies were therefore taken up to assess the corrosion of synthesized biodiesel from the above mentioned non-edible oils.Using long duration static immersion test method corrosion studies on engine parts like piston metal and piston liner were carried out with neat diesel procured from one of the Indian refinery and biodiesel synthesised from these non-edible oils. Biodiesel from Salvadora showed marked corrosion on both metal parts of diesel engine whereas biodiesel from other oils showed little or/no corrosion as compared to neat diesel.