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

Alaaddin M M Saeed; Shivika Sharma; Saeikh Zaffar Hassan; Atef M Ghaleb; Gui-Ping Cao

doi:10.1021/acsomega.3c02434

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

ACS Omega. 2023 Jul 14;8(29):26206-26217. doi: 10.1021/acsomega.3c02434. eCollection 2023 Jul 25.

Authors

Alaaddin M M Saeed^{1

2}, Shivika Sharma², Saeikh Zaffar Hassan², Atef M Ghaleb³, Gui-Ping Cao¹

Affiliations

¹ UNILAB, State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
² Department of Petroleum Studies, Zakir Husain College of Engineering and Technology, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh 202002, India.
³ Department of Industrial Engineering, College of Engineering, Alfaisal University, 11533 Riyadh, Saudi Arabia.

Abstract

The acid-catalyzed pre-treatment esterification process is required for low-cost feedstock with high free fatty acids (FFAs) to avoid the saponification that occurs during alkali-catalyzed transesterification for the production of fatty acid alkyl esters (FAAE). Reverse hydrolysis in acid-catalyzed esterification causes a decrease in fatty acid methyl ester (FAME) yield. Therefore, the esterification process must be intensified. This study aims to develop and optimize a low-temperature intensification process to enhance biodiesel yield and reduce energy consumption. Three intensification systems were studied: co-solvent technique, co-solvent coupled with adsorption of water using molecular sieves, and entrainer-based continuous removal of water. The process variables of esterification reaction in co-solvents without the adsorption system were optimized by using central composite design (CCD). The study showed that the co-solvent without the adsorption system was effective 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 required for sufficient vapors in the adsorption system. Optimized process variables have achieved 95% X_FFA within 75 min at 55 °C, 20 mL/100 g of oil DEE, 9 MR, 3 wt % H₂SO₄, and 320-350 RPM in a co-solvent without the adsorption system.