Vegetable Oil Based Microemulsion Biofuels

Abstract

The growth of energy demand increases dramatically which has resulted in an increase of exhaust emissions to air quality deterioration. Therefore, there are driving forces in the development of renewable energy production technologies. Vegetable oils based reverse micelle microemulsions have been increased in attention for biofuel production. This work aims to formulate microemulsion biofuel containing palm oil/diesel blend as nonpolar phase, and ethanol/butanol, as a polar phase. The nonionic alcohol ethoxylate surfactant with the different numbers of EO groups, EOn (n=1, 3, 5, and 9) were selected as a stabilizing agent. A pseudo-ternary phase diagram was conducted to determine an isotropic region in the phase behavior of microemulsion systems. The ability of butanol added for reducing the phase separation and amount of surfactant required to form the microemulsified fuels was explored. Together with, the effects of surfactant structures and cosurfactant structures, straight chain (1-octanol) and branch chain alcohol (2-ethyl-1-hexanol) were investigated systematically through their phase behaviors. The fuel properties (i.e., kinematic viscosity, droplet size, density, heating value) were examined and compared with neat biofuels. The results suggest that the percentage of surfactant used to stabilize the microemulsion decreased with increasing butanol fraction in the mixture of butanol/ethanol blend. The microemulsion with branching structure in cosurfactant required more surfactant to formulate the microemulsions. The addition of butanol to palm oil/diesel blended with ethanol affecting fuel properties was noted.