Catalytic Conversion of Triglycerides to Liquid Biofuels Through Transesterification, Cracking, and Hydrotreatment Processes

Abstract

Biofuels derived from biomass have recently received much attention due to depleting petroleum resources, and increasing energy consumption and cost. Biodiesel is considered a first generation biofuel produced from well refined vegetable oils by transesterifying triglycerides with methanol. The biodiesel market is potentially very large and can be sold into the worldwide petroleum diesel market as a blended fuel. First generation biodiesel production technologies are based on homogeneous basic catalysts such as NaOH, KOH. However, the future direction is to develop heterogeneous catalytic process to simplify the present technologies. This article reviews current routes for the catalytic conversion of triglycerides into biofuels through transesterification, catalytic cracking, and hydrotreatment.Broadly, second generation biofuels are renewable fuels composed of hydrocarbons produced from refined oil, crude oil and waste feedstocks that have been catalytically cracked or hydrotreated. These hydrocarbons have a chemical structure similar to petroleum-based fuels and possess superior stability and storage properties in comparison with biodiesel. Present second generation biofuel research focuses on the usage of the commercialized fluid catalytic cracking (FCC) and hydrogenation catalysts used in petroleum industry and existing petroleum refinery infrastructure for creating renewable diesel fuel in order to avoid additional capital investment for new equipment. This review discusses the feedstocks, chemistry, catalysts, and challenges involved in the production of both the first and second generations of biofuels. Keywords: Triglyceride, heterogeneous catalyst, biofuels, transesterification, cracking, hydrotreatment, liquid, chemical structure, catalytic cracking, gasification, fermentation, BIODIESEL, Transesterification Chemistry, homogeneous catalysts