Application of co-solvent for biodiesel production in ultrasound-assisted reactor

Abstract

Biodiesel has been a promising alternative energy due to its renewability and lesser emissions of harmful gases such as carbon monoxide in comparison to traditional petroleum diesel fuel. Mostly, biodiesel production via transesterification requires catalyst to achieve faster reaction rate and complete the reaction. However, mass transfer between two immiscible reactants are obstacle to the biodiesel production. In this work, ultrasound-assisted (US) reactor and addition of co-solvent were used to overcome mass transfer limitation. The condition for biodiesel production from transesterification of palm oil using a circulated US reactor and addition of co-solvent was operated at 60°C, 1 atm, calcium oxide loading (10 %wt), and methanol to oil molar ratio of 9:1. It was found that using methanol to methyl myristate (co-solvent) volume ratio of 1:0.1 gave the highest biodiesel yield (about 95.31 %). Moreover, using the mixture of acetone and methyl myristate as a co-solvent can improve the biodiesel production efficiency because it can increase the solubility of reactants and active sites of calcium oxide catalyst. The results also reported that the higher ultrasound frequency and power combined with co-solvent provides increasing biodiesel yield from 14.07 to 91.75 %. Therefore, the application of co-solvent for biodiesel production in the circulated US reactor can improve biodiesel yield. The knowledge from this study can be developed for the further process scale up.