REMOVAL OF FREE FATTY ACID IN CRUDE JATROPHA CURCAS OIL USING FERRIC SULPHATE FOR BIODIESEL PRODUCTION

Application of Jatropha curcas oil has been found in various fields including energy. It is well known that quality of biodiesel produced depends partly on raw material quality. In biodiesel production, high free fatty acid content in crude Jatropha curcas oil resulting from inappropriate storage and handling, is one of the most considerable problems. Hence, the aim of this research was to optimize the condition for removal of free fatty acid in crude Jatropha curcas oil by esterification using ferric sulphate as the catalyst. The reaction variables, such as methanol to crude Jatropha curcas oil molar ratios (6:1-15:1), ferric sulphate amount (1-2.5 wt%), temperature (45-70 O C), and reaction time (1-3 h), were applied. It was found that the condition having the methanol to crude Jatropha curcas oil molar ratio of 9:1, ferric sulphate at 1.5 wt%, the reaction temperature at 65 O C, and the reaction time at 2 h was successful for reducing the amount of free fatty acids in crude Jatropha curcas oil to below 1 wt%, and yielded 84% of esterified oil. This optimum condition was also applied for improving quality of crude rubber seed oil with high free fatty acid content. In addition, more than 90% of free fatty acid could be removed resulting in high quality of crude rubber seed oil. When this esterified oil was employed in biodiesel production, it gave high quality of biodiesel whose properties met the Thai biodiesel (B100) specifications.