Modelling and Optimization of Hydrogen Production from Bi-Reforming of Methane Using Respond Surface Methodology

Abstract

The global demand for clean and sustainable energy has intensified interest in hydrogen as a versatile energy carrier, with methane bi-reforming emerging as a promising pathway for its production. This study investigates the optimization of hydrogen yield in a methane bi-reforming process using Aspen HYSYS simulations integrated with Response Surface Methodology (RSM) via Design Expert software. A Central Composite Design (CCD) experimental matrix was employed to analyse the effects of temperature (800–900°C), pressure (2–5 bar), and steam-to-carbon (S/C) ratio (0.33–1.0) on hydrogen production. A quadratic model was identified as the most suitable, achieving an R² of 0.9953, explaining 99.53% of the variability in hydrogen yield, with a low standard error and robust predictive accuracy (adjusted R² = 0.9911, predicted R² = 0.9593). The S/C ratio emerged as the dominant factor (coefficient = +47.92), followed by temperature (+14.13), while pressure had a negative effect (12.03). Optimal conditions, including a temperature of 895.079°C, pressure of 2.114 bar, and S/C ratio of 0.970, yielded a predicted hydrogen output of 271.132 mol/h with a standard error of 2.925 mol/h and a desirability score of 1.000. Synergistic interactions, particularly between temperature and S/C ratio, were confirmed through 3D surface and contour plots, while pressure showed diminishing returns beyond 2.6 bar. Diagnostic analyses validated the model’s robustness, despite a significant lack of fit, ensuring its reliability for industrial applications. The findings, supported by StatEase (2023), provide a robust framework for designing efficient bi-reforming processes, advancing sustainable hydrogen production. Future work should explore broader parameter ranges, incorporate additional factors, and validate results experimentally to enhance practical applicability.