Performance and emission analysis of diesel engine fueled with blends of diesel S500, biodiesel, soybean oil, waste cooking oil, and alcohol-based cosolvents

The use of fuel emulsions has garnered increasing attention over the past decade as a potential route to replace fossil fuels with more sustainable and technologically feasible alternatives. This study explores the incorporation of oxygenated biocomponents, such as refined vegetable oil, waste cooking oil, ethanol, and octanol, into diesel B S500 (a blend of diesel containing 10% biodiesel and 500 ppm sulfur). A key challenge associated with the high viscosity of vegetable oils, when used directly without prior transesterification, was successfully addressed by the addition of an ethanol/octanol cosolvent. Acting as a surfactant, the cosolvent enabled the formation of homogeneous and stable emulsions, maintaining stability for up to 90 days. The resulting fuel emulsions exhibited properties, including calorific value, viscosity, cold filter plugging point, oxidation stability, and atmospheric distillation, that were comparable with standard diesel B, ensuring suitability for common fuel applications. Engine performance tests showed similar results to diesel B, with certain formulations significantly reducing hydrocarbon and carbon monoxide emissions. Additionally, formulations incorporating neutralized waste cooking oil delivered promising outcomes, reinforcing the feasibility of repurposing waste oils. Fuel emulsions offer a complementary solution to the existing biodiesel industry, providing an environmentally sustainable alternative, particularly in regions distant from centralized processing facilities for vegetable oils and animal fats.