Intrinsic kinetics of CO2 methanation over an industrial nickel-based catalyst

The intrinsic kinetics of CO2 methanation over an industrial nickel-based catalyst was determined for a temperature range between 250 °C to 350 °C. The kinetic experiments were performed operating an integral fixed-bed reactor far from equilibrium conditions, in the absence of heat and mass resistances and at the atmospheric pressure. Five mechanistic-based models for describing the reaction kinetics were taken from literature and used for fitting the experimental reaction rates. Model discrimination was based on the assessment of the thermodynamic consistency and statistical significance of inherent parameters (for 95% confidence level). Comparison of the adequacy of fit between accepted models was done through the determination of the corresponding F-values to select the best model. The selected model assumes a formyl intermediate mechanism with a hydroxyl group being the most abundant species. The proposed reaction kinetics was further validated by the simulation of an isothermal plug-flow reactor operating at the same experimental conditions employed in this work, where a reasonable agreement between model predictions and the observed values was obtained