Saeed Alaaddin M M, Sharma Shivika, Hassan Saeikh Zaffar, Ghaleb Atef M, Cao Gui-Ping
UNILAB, State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
Department of Petroleum Studies, Zakir Husain College of Engineering and Technology, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh 202002, India.
ACS Omega. 2023 Jul 14;8(29):26206-26217. doi: 10.1021/acsomega.3c02434. eCollection 2023 Jul 25.
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 () 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% within 75 min at 55 °C, 20 mL/100 g of oil DEE, 9 MR, 3 wt % HSO, and 320-350 RPM in a co-solvent without the adsorption system.
对于含有高游离脂肪酸（FFA）的低成本原料，需要进行酸催化预处理酯化过程，以避免在碱催化酯交换反应生产脂肪酸烷基酯（FAAE）过程中发生皂化反应。酸催化酯化过程中的逆水解会导致脂肪酸甲酯（FAME）产率降低。因此，必须强化酯化过程。本研究旨在开发和优化一种低温强化工艺，以提高生物柴油产率并降低能耗。研究了三种强化系统：共溶剂技术、共溶剂与分子筛吸附水相结合以及基于夹带剂的连续除水。采用中心复合设计（CCD）对无吸附系统的共溶剂中酯化反应的工艺变量进行了优化。研究表明，与其他两种系统相比，无吸附系统的共溶剂在低温下强化FFA转化（）方面是有效的，这是由于吸附系统中产生足够蒸汽所需的高共溶剂/夹带剂用量下的稀释效应。在无吸附系统的共溶剂中，优化后的工艺变量在55℃、20 mL/100 g油二乙氧基乙烷（DEE）、9的醇油摩尔比（MR）、3 wt%硫酸（HSO）和320 - 350转/分钟的条件下，75分钟内实现了95%的转化率。
