Experimental study on energy and environmental impacts of alcohol-blended water emulsified cottonseed oil biodiesel in diesel engines

The increasing concern over environmental pollution and energy security has intensified the search for alternative fuels. This study explores the impact of 1-pentanol blends on the combustion performance and emission characteristics of water-emulsified Gossypium hirsutum (cottonseed) oil biodiesel in a compression ignition engine. Cottonseed oil was converted into biodiesel via transesterification, and its elemental, chemical, and physicochemical properties were thoroughly analyzed. A key contribution of this work is the formulation of a fuel blend comprising 30 % cottonseed oil biodiesel (COB) by volume mixed with diesel fuel, further emulsified with 10 % water by volume. The water-emulsified biodiesel was then enhanced with a 10 % volume concentration of 1-pentanol. The energy and environmental performance of these test fuels were evaluated in a single-cylinder compression ignition engine under various operating conditions. The study's findings reveal that the alcohol-blended, water-emulsified biodiesel significantly improves combustion efficiency and reduces emissions compared to conventional diesel fuel. Notably, the addition of 10 % 1-pentanol to the water-emulsified biodiesel led to a 14.3 % reduction in hydrocarbon emissions and a 12.8 % reduction in carbon monoxide emissions. Furthermore, there was a 3.2 % improvement in brake thermal efficiency and a 1.4 % decrease in specific fuel consumption. This research demonstrates that blending alcohol with water-emulsified biodiesel not only enhances combustion efficiency but also offers a promising strategy for reducing the environmental impact of diesel engines and potentially lowering fossil fuel dependence by 50 %.