Formulation and Extension of Diesel-Based Microemulsion Fuels for Compression Ignition Engines

Abstract

There is a need for sustainable alternative fuels which can address and alleviate both economical and environmental issues. The current work is based on alcohol–diesel–water microemulsion fuels. Microemulsions are thermodynamically stable and isotropic dispersions of oil, water, and an amphiphile. Diesel is used as the oil phase in microemulsion while water in it reduces the combustion temperature which, in turn, reduces the NO_x and smoke emissions. In this work, an alcohol has been used, that acts both as a surfactant and a co-surfactant, thereby making the process facile and economical. The microemulsion regions are mapped out in ternary phase diagrams. The initial measurements suggest that the microemulsions have a higher calorific value, and lesser soot and residue formation as compared to that with neat diesel. The microemulsions also have properties such as density, viscosity, flash and fire points, and cloud and pour points close to those of neat diesel. The effect of various ionic and non-ionic surfactants on the extent of microemulsion region has also been studied. Hydrophilic surfactant expands the microemulsion domain while hydrophobic surfactant shrinks the same. Cationic surfactant does not have much influence on the microemulsion domain, while an anionic surfactant surprisingly does not yield any microemulsions by the current methodology.