Biodiesel production via transesterification of palm olein using sodium phosphate as a heterogeneous catalyst

Abstract

The production of Fatty Acid Methyl Esters (FAMEs) via the transesterification reaction of palm olein and methanol using sodium phosphate (Na3PO4) as a heterogeneous catalyst has been investigated. This study determined the influence of various parameters, such as the methanol to oil molar ratio, the operating temperature, the amount of catalyst, and the presence of water and free fatty acid in the raw materials, on the rate of reaction. The study demonstrated that Na3PO4 can be used effectively as a heterogeneous catalyst in transesterification process. It was determined that increasing the methanol to oil molar ratio results in an increase in equilibrium conversion. A molar ratio of methanol to oil of 18:1 provides the fastest rates of reaction and the highest FAME content. The operating temperatures have a strong effect on FAME yield; increasing the reaction temperature tends to accelerate the rate of reaction but reduces the glycerol by-product quality. Under the study conditions, with a methanol to oil molar ratio of 18:1 and a reaction temperature of 210°C 98.5% FAME yield was obtained within 30min with only 1wt.% of Na3PO4. When a large excess of methanol was used, the experimental results agreed with the irreversible 1st order kinetic model, while the activation energy was found to be 32.59kJ/mol palm olein.