Influence of Some Emulsifiers in Improving the Biofuel Characteristics

Molecules’ characteristics of the active surface, such as low molecular weight fatty acids, asphaltene, and naphthenic acids determine the properties of emulsified fuels. They can interact with surfaces from other oils, water from liquid mixtures, solid surfaces from mechanical systems, or with pipes walls in case of long distances transport. For heavy oils which contain large amounts of asphaltene, these effects are very important. The characteristics of the emulsified fuels are determined mainly by the properties and nature of the emulsifier. In the present paper, some tests for heavy fuels emulsification with monoglycerides and cosurfactants are mentioned, due to their significant contributions in clean fuels combustion. This first proposed solution, presented in this paper is generally preferred, due to its small cost. The second tested solution consists in nonionic polymer obtained from the solid wastes of PET (polyethylene terephthalate) conversion and glycol. The main advantages of this raw material are the PET’s low cost and its large availability. The PET has high content of oxygen so the combustion of emulsified fuels with this type of surfactants assures low pollution emission. The preparation of the nonionic polymer associated with the glycerol recovery as additives for emulsified fuels is also mentioned. As the first stage, the PET transesterification with glycol at 200°C–210°C with ethylene glycol elimination was mentioned. For experiments, ten samples of emulsified fuels with different emulsifying agents were prepared, being tested their influence on fuel characteristics. Some physical properties of the emulsified fuel as the density at 20°C, viscosity at 90°C, flash point, and the freezing points were also determined. If the emulsifier proportion or the water quantity increase in the emulsified fuel the flash point increases also. Other experiments were realized referring to the freezing point and viscosity’s dependence with temperature. Finally, are presented some remarks concerning the proper report between emulsifier and final fuel properties.