Oxidation Stability of Fatty Acid Methyl Ester under Three Different Conditions

Abstract

Maintaining fuel stability is one important criterion in sustaining the quality of fuels. This research investigated the production of biodiesel from waste groundnut oil and the oxidation stability of the biodiesel samples stored under three conditions (a vacuum, a fridge and an exposure to atmosphere) by considering their saponification values, percentage of free fatty acid, peroxide values, iodine values and viscosity. Maximum biodiesel yield was obtained at 9 methanol/oil mole ratio, 1.0w/w%Oil KOH catalyst concentration, reaction time of 60 minutes and reaction temperature of 60 ⁰C. The results showed that biodiesel oxidation stability is adversely affected by increase in saponification value, percentage of free fatty acid, peroxide value; and decrease in iodine value and viscosity. Also, the results of these physico-chemical properties shows that vacuum is the most favourable storage condition, compared to freezing and atmospheric conditions.

Keywords: Atmosphere, Biodiesel, Refrigerator, Trans-esterification, Vacuum