Emulsification of animal fats and vegetable oils for their use as a diesel engine fuel: An overview

Vegetable oils and animal fats represent promising alternatives to diesel engine fuel because they can be obtained from different feedstocks and renewable sources; also their properties are close to diesel fuel. The direct use of these biofuels as a diesel engine fuel can cause several problems in engine performance and emissions. In order to obtain a more engine-friendly fuel, it is necessary to change the biofuels’ properties for which different methods have been used. One of the possibilities is using emulsification techniques in order to obtain emulsified biofuels (emulsions or microemulsions); through this method it is possible to lower viscosity and improve the atomization. However, emulsification techniques applied to vegetable oils and animal fats have not been studied thoroughly. For this reason, this paper presents an overview on the formulation and characterization of the emulsified biofuels using vegetable oils and animal fats, as well as the main experimental results reported about its use as a diesel engine fuel in the scientific literature.