Formulation of microemulsion-based biofuels via the HLD framework

Abstract

The attention given to reverse micelle microemulsion for biofuel production has increased over the years. For Winsor Type II microemulsion systems using vegetable oil/diesel blends as an oil phase and an alkanol (i.e., ethanol) as a polar phase, surfactants with or without cosurfactants play a crucial role in the formulations. In this work, the microemulsion biofuel formulations were reviewed and discussed with regard to the formulation compositions (i.e., polar phase, oil phase, surfactant, and cosurfactant). The optimized systems in the literature were selected to calculate the HLD values. The HLD concept was investigated to predict the formulations, especially the total surfactant and cosurfactant concentration, for specific microemulsion biofuels. From the published experimental data set, correlations relating to the characteristics of the surfactant, cosurfactant, polar phase, and oil were examined. The results indicate that the HLD concept can be a useful tool to predict and provide the appropriate range of the surfactant/cosurfactant amount at the laboratory scale, which can then be developed and extended to the industrial scale in biofuel production.