Waste cooking oil (WCO) presents a viable raw material for biodiesel production, offering a twofold solution to waste management and renewable energy generation. In the present study, the production of biodiesel from WCO was investigated using methanol as the solvent under non-catalytic supercritical conditions. Experiments were performed by varying key process parameters, such as temperature (200–400 °C), pressure (100–200 barg), residence time (0–60 min), and methanol-to-oil molar ratio (10–50 mol/mol) to assess their effects on biodiesel yield. Response surface methodology was used to assess the interactions between different process parameters and to determine the optimal conditions for achieving maximum biodiesel yield. A reduced quadratic regression model was developed, and the results were validated and found to be within the 95% two-sided confidence interval, indicating reliable model predictions. Modeling, simulation, and analysis were performed using the Aspen Plus® software based on experimental data of optimal conditions to assess the viability of the process. This combined experimental–modeling approach provides a robust basis for promoting economic viability and exploring opportunities for industrial-scale implementation. Overall, this research underlines the potential of supercritical technology as a sustainable method for biodiesel production and securing clean energy for the future.
