Current biodiesel production technologies: A comparative review

Despite the high energy demand in the industrialized world and the pollution problems caused by widespread use of fossil fuels, the need for developing renewable energy sources with less environmental impacts are increasing. Biodiesel production is undergoing rapid and extensive technological reforms in industries and academia. The major obstacle in production and biodiesel commercialization path is production cost. Thus, in previous years numerous studies on the use of technologies and different methods to evaluate optimal conditions of biodiesel production technically and economically have been carried out. In this paper, a comparative review of the current technological methods so far used to produce biodiesel has been investigated. Four primary approaches to make biodiesel are direct use and blending of vegetable oils, micro-emulsions, thermal cracking (pyrolysis) and transesterification. Transesterification reaction, the most common method in the production of biodiesel, is emphasized in this review. The two types of transestrification process; catalytic and non-catalytic are discussed at length in the paper. Both advantages and disadvantages of the different biodiesel production methods are also discussed.

► In this paper we review the technologies related to biodiesel production.
► 4 Primary approaches reviewed are direct use and blending of oils, micro-emulsions, pyrolysis and transesterification method.
► Both advantages and disadvantages of the different biodiesel production methods are also discussed.
► The most common technology of biodiesel production is transesterification of oils.
► Selection of a transesterification method depends on the amount of FFA and water content of the feedstock.