Experimental Optimization of Mahua Biodiesel Performance Using Butylated Hydroxytoluene (BHT) and Ascorbic Acid Additives

Abstract

The present study focuses on the experimental optimization of Mahua (Madhuca indica) biodiesel performance using Butylated Hydroxytoluene (BHT) and Ascorbic Acid as antioxidant additives to enhance fuel stability and engine efficiency. Biodiesel produced from Mahua oil via base catalyzed transesterification was blended with diesel in proportions of biodiesel blends. A single cylinder, four-stroke diesel engine was used to test the effects of different BHT and ascorbic acid concentrations (500–2000 ppm) on the blend's oxidative stability, combustion, and emission properties. The experiments were designed using the Response Surface Methodology (RSM) to identify the optimum additive concentration for improved performance. Results revealed that BHT improved oxidation stability and reduced nitrogen oxide (NOx) emissions, while Ascorbic Acid demonstrated superior control over carbon monoxide (CO) and unburned hydrocarbon (HC) emissions. The optimized blend, B20 with 1500 ppm BHT, achieved the highest Brake Thermal Efficiency (BTE) and lowest Specific Fuel Consumption (SFC) among all tested samples. Statistical analysis confirmed strong model accuracy with a desirability index above 0.9. Overall, the study demonstrates that the combined application of antioxidants significantly enhances the storage stability, combustion efficiency, and emission performance of Mahua biodiesel, positioning it as a sustainable and oxidation-resistant fuel for compression ignition engines.