Modified diesel prepared by stabilization of water as nanodroplets in diesel/colza oil blend: Study of phase behavior and affecting parameters

In recent decades, using of vegetable oils has gained major attention as an alternative and renewable fuel source. But, the high viscosity of vegetable oils makes them to be problematic for the fuel engines in long-term use. Blending of vegetable oils with diesel as modified diesel fuel has been considered as the most common method for reducing the negative effects of vegetable oils, such as high viscosity. The main purpose of this research is to study the phase behavior of new w/o microemulsion systems with focus on formulating an optimized fuel system. The effects of several parameters such as surfactant, co-surfactant, blends of several surfactants (HLB), temperature, stirring speed and stirring time on the physical properties of the studied systems, such as viscosity, water droplet sizes were examined. The optimum system formulated here was composed of diesel/colza oil blend (80:20 wt%) 44 wt%, Span 80 as surfactant 4 wt%, 1-butanol as co-surfactant 47 wt% and 5 wt% water. The size of water droplets in the formulated optimum system has been about 4.6 nm and the system showed no phase separation for up to 9 months on the shelf.