Properties improvement of microemulsion fuel from ethanol-jatropha oil-diesel by surfactant selection

Abstract

At present, jatropha oil biodiesel is one of interesting renewable fuel for assuring an energy security and environmental quality. Transesterification is the most common method to reduce the viscosity of vegetable oils. However, on of the problems of transesterification process are low quality of glycerol by-product and large volume of wastewater. Therefore, microemulsion fuels from microemulsification have been introduced as an alternative method to produce proper fuel and avoid problems of waste disposal. In this study, microemulsion fuels (MFs) are produced from jatropha oil, ethanol with surfactants and diesel. The results from pseudo-ternary phase diagram show the single phase of jatropha oil, ethanol and diesel at the optimum condition with both single and mix surfactant systems. Subsequently two MFs ratio were selected based on clear phase behavior to study properties. The first ratio is comprised of 20% jatropha oil, 75% diesel and 5% single or mix surfactant in ethanol solution and the second is 20% jatropha oil, 70% diesel and 10% single or mix surfactant in ethanol solution. The ethanol with sinngle or mix surfactant ratio was set at 3:1. For the properties of the selected MFs, kinematic viscosity and water content, which are the most importance in fuel properties, were found to meet the standard value for biodiesel while acid number and flash point did not meet biodiesel standard (ASTM and EN). In addition, MFs were examined for the engine performance and exhuasted emission. It was found that MF(E5)-S1 has power, BSFC (brake specific fuel consumption), and exhaust gas temperature similar to those of diesel. For emission, MFs showed lower smoke than those of diesel while CO and CO2 emissions were similar to those of diesel. Thus, the microemulsion fuel of MF(E5) by microemulsification method show great potential to use as biofuel in diesel engines without modification.