Development of Purification Process Using Electrocoagulation Technique for Biodiesel Produced via Homogeneous Catalyzed Transesterification Process of Refined Palm Oil

¹ Chemical and Process Engineering Program, The Sirindhorn International Thai-German Graduate School of Engineering (TGGS), King Mongkut’s University of Technology North Bangkok, Bangkok, Thailand
² Electrical Power and Energy Engineering Program, The Sirindhorn International Thai-German Graduate School of Engineering (TGGS), King Mongkut’s University of Technology North Bangkok, Bangkok, Thailand

^* Corresponding author: tawiwan.k@tggs.kmutnb.ac.th

Abstract

This work is focused on the preliminary development of purification process using electrocoagulation technique for biodiesel produced via homogeneous catalyzed transesterification process of refined palm oil (RPO) to shorten the separation process and reduce the water consumption during the final purification with water-washing process. Biodiesel as Fatty acid methyl esters (FAMEs) were produced via transesterification reaction of RPO as feedstock with methanol in the presence of sodium hydroxide derivative-catalyst at the optimal condition using conventional heating. Electrocoagulation separation process was in-house designed to investigate the effects of electrode configurations such as shapes, distances between electrodes and suitable applied AC high voltages (ranging from 1 to 9 kV) on the separation efficiency of glycerol and biodiesel. Results revealed that with the electrocoagulation process at room temperature using AC electrical current at high voltage of 3 kV (and low amperage) with a point to point electrode configuration and the vertical-distance between electrodes of 3 cm was very efficient and achieved higher free glycerol removal than using the conventional separation of the gravitational settling. Furthermore, the separation time was significantly shortened from typically > 24 h with the gravitational settling to 240 s (4 min) and the number of water-washing was reduced from 5 to 3 times during the final purification process. The final purity of biodiesel was 98.89%±0.25% with high quality according to standards of EN 14214 and ASTM D6751.