Production of methyl esters from palm oil with high content of free fatty acids

Abstract

The objective of this study is to investigate the production of methyl esters by two step method. Palm olein oil and palm fatty acids distillate were used as raw materials and were mixed at a ratio of 4.5% of free fatty acids. The experiments were carried out in a batch reactor using an oil mixture and methanol. A non-catalytic esterification reaction is used in the first step. The experiments were conducted at temperatures of 60, 150, 200 and 250C, at pressures of 14.7, 500 and 1000 psia and at methanol to oil molar ratio of 3:1, 6:1 and 9:1. In the second step, methyl esters was produced by transesterification reaction using sodium methylate as an alkaline catalyst. The reactions were conducted at a molar ratio of methanol to oil of 6:1 and at a temperature of 60C and at ambient pressure. The results indicate that esterification reaction of free fatty acid content in palm oil can occur when temperature is higher than 150C and pressure is higher than 1000 psia. The suitable conditions of esterification reaction reduce free fatty acid content from 4.5% to less than 2% are a temperature of at least 150C, a pressure of at least 1000 psia and at methanol to oil molar ratio of at least 6:1 in 1 hr. The second step, the results indicate that the final yield of methyl esters was achieved at 90% in 1 hr.