A kinetic model for a single step biodiesel production from a high free fatty acid (FFA) biodiesel feedstock over a solid heteropolyacid catalyst

作     者：Aashish Gaurav Stéphane Dumas Chau T.Q.Mai Flora T.T.Ng 

作者机构：Department of Chemical Engineering University of Waterloo 

出 版 物：《Green Energy & Environment》 (绿色能源与环境（英文版）)

年 卷 期：2019年第4卷第3期

页      面：328-341页

核心收录：

学科分类：081702[工学-化学工艺] 081705[工学-工业催化] 08[工学] 0817[工学-化学工程与技术] 

基　　金：Financial support from the Natural Sciences and Engineering Research Council of Canada financial support for an exchange scholarship by the Chemistry Department of University Pierre and Marie Curie and FSDIE (Fonds de Solidarite et de Developpement des Initiatives Etudiantes) 

主　　题：Yellow grease Canola oil Free fatty acids Heteropolyacid Kinetics for esterification and transesterification 

摘      要：Production of biodiesel from yellow grease(waste cooking oil and waste animal fats) is fast emerging as a promising alternative to address the twin challenges before the biodiesel industry today-fluctuation in prices of vegetable oil and the food versus fuel debate. Yellow grease has a high percentage of free fatty acids(FFA) and proves to be an unsuitable feedstock for biodiesel production from commercially viable alkalicatalyzed production systems due to saponification problems. Green methodologies based on heterogeneous solid acid catalyzed reactions have the potential to simultaneously promote esterification and transesterification reactions of yellow grease to produce biodiesel without soap formation and offer easy catalyst separation without generation of toxic streams. This paper presents kinetic studies for the conversion of model yellow grease feeds to biodiesel using a heteropolyacid supported on alumina(HSiW/Al2O3) using a batch autoclave. Three model yellow grease feeds were prepared using canola oil with added FFA such as palmitic, oleic and linoleic acid. A pseudo homogeneous kinetic model for the parallel esterification and transesterification was developed. The rate constants and activation parameters for esterification and transesterification reactions for the model yellow grease feeds were determined. The rate constants for esterification are higher than the transesterification rate constants. The kinetic model was validated using the experimental biodiesel data obtained from processing a commercial yellow grease feed. The kinetic model could be used to design novel processes to convert various low-value waste oils, fats and non-food grade oils to sustainable biodiesel.