Impact of antioxidant and metals on biodiesel stability-a review

The rise in petroleum price and uncertainties in fossil fuel availability,there is renewed interest in vegetable oil fuels for diesel engines. the vegetable oil can be used as alternative fuel to diesel. but there are two problems associated with use of vegetable oil as fuel are oxidation stability and cold flow property. the use of vegetable oil as bio fuel is limited due to poor stability characteristics of this oil. the poor stability leads to gum formation which further leads to storage problem of these fuels for longer period of time. the high temperature engine performance is also affected due to poor thermal stability of the bio fuel obtained from vegetable oil. to overcome these stability related problems various chemical substances (natural as well as synthetic) in nature are used as antioxidants. these antioxidants improve the stability characteristics of bio fuels. the impact of various metals on the oxidation stability of various bio fuel sources is also investigated in the paper. the result of the investigation shows that aluminium and cast iron container are best for storage and transportation of biodiesel. the comparative study also shows that pyrogallol is best antioxidant for improving the stability.