Intensification and Optimization of FAME Synthesis via Acid-Catalyzed Esterification Using Central Composite Design (CCD)

The acid-catalyzed pre-treatment esterification processis requiredfor low-cost feedstock with high free fatty acids (FFAs) to avoidthe saponification that occurs during alkali-catalyzed transesterificationfor the production of fatty acid alkyl esters (FAAE). Reverse hydrolysisin acid-catalyzed esterification causes a decrease in fatty acid methylester (FAME) yield. Therefore, the esterification process must beintensified. This study aims to develop and optimize a low-temperatureintensification process to enhance biodiesel yield and reduce energyconsumption. Three intensification systems were studied: co-solventtechnique, co-solvent coupled with adsorption of water using molecularsieves, and entrainer-based continuous removal of water. The processvariables of esterification reaction in co-solvents without the adsorptionsystem were optimized by using central composite design (CCD). Thestudy showed that the co-solvent without the adsorption system waseffective in intensifying the FFA conversion (X (FFA)) at low temperatures, compared to the other two systems,due to the dilution effect at high co-solvent/entrainer amount requiredfor sufficient vapors in the adsorption system. Optimized processvariables have achieved 95% X (FFA) within75 min at 55 & DEG;C, 20 mL/100 g of oil DEE, 9 MR, 3 wt % H2SO4, and 320-350 RPM in a co-solvent without theadsorption system.