Supercritical Fluid Technology in Biodiesel Production: A Review

Abstract

The finite nature of fossil fuels necessitates consideration of alternative fuels from renewable sources. The term biofuel refers to liquid, gas and solid fuels predominantly produced from biomass. Biofuels include bioethanol, biomethanol, biodiesel and biohydrogen. Biodiesel, defined as the monoalkyl esters of vegetable oils or animal fats, is an attractive alternative fuel because it is environmentally friendly and can be synthesized from edible and non-edible oils. Various methods have been reported for the production of biodiesel from vegetable oil and fats such as Transesterification, non-catalytic Supercritical fluid technology, micro emulsion, pyrolysis etc. In this article, the potential of supercritical fluids (SCF) as a sustainable route for biodiesel production is discussed and compared with conventional catalytic reactions. Although, the advantages of catalyst free SCF process are apparent; there are concerns regarding the huge energy required to conduct supercritical reaction at elevated temperature and pressure. Hence, there are challenges facing SCF process which need to be addressed before it could be a sustainable technology in the future.

Keywords: Supercritical fluid, Biodiesel, Biofuel, Non-catalytic, Alcohol.