Esterification of tall oil fatty acid catalyzed by Zr4+-CER in fixed bed membrane reactor

Abstract

In this study, Zr4+-CER was used as a solid acid catalyst to catalyze the esterification reaction. The esterification of tall oil fatty acids (TOFA) with ethanol dehydration was studied by fixed-bed coupled pervaporation (PV). The Zr4+-CER catalyst was characterized in detail by Py-IR, NH3-TPD, BET, IEC, ICP-OES, SEM, and FTIR. The effects of ethanol/oil molar ratio, catalytic bed height, reaction temperature and feed rate on TOFA conversion were investigated. The esterification reaction conditions were optimized by orthogonal test, and the optimal conditions were ethanol/oil molar ratio 15:1, catalytic bed height 120 mm, reaction temperature 80 °C, and feed rate 0.3 ml/min. The TOFA conversion rate was 99.51 %. After six esterification cycles, the TOFA conversion of the catalyst reached 90.03 %, indicating that the catalyst had high stability. The esterification process using Zr4+-CER as the catalyst follows the second-order kinetic model, with an activation energy of 39.54 kJ/mol. Furthermore, the economic analysis of biodiesel production indicates that the Zr4+-CER catalyst has the potential to decrease production expenses, presenting an encouraging prospect for future biodiesel industrialization.