Kinetic Modeling of Combined Steam and CO<sub>2</sub> Reforming of Methane over the Ni–Pd/Al<sub>2</sub>O<sub>3</sub> Catalyst Using Langmuir–Hinshelwood and Langmuir–Freundlich Isotherms
Danial Batebi, Reza Abedini, Amir Mosayebi
Abstract
Combined steam and CO2 reforming of methane (CSCRM) testing was used to determine the responses of CH4 conversion, H2 and CO yield, and CO2 conversion at a temperature range of 500–1000 °C, (CO2 + H2O)/CH4 ratio of 1–3, and CO2/H2O ratio of 1–3, over the Ni–Pd/Al2O3 catalyst in a fixed bed reactor. The Ni–Pd/Al2O3 catalyst was synthesized through the sol–gel method, and its chemical and physical properties were studied using transmission electron microscopy, scanning electron microscopy, H2 chemisorption, and O2-pulse titration methods. A kinetic model for the CSCRM reaction was also developed based on Langmuir–Hinshelwood and Langmuir–Freundlich isotherms by ignoring the deactivation reactions. The results showed that experimental H2 yield values were closer to the modeled values compared to other cases. The proposed kinetic model resulted in the highest accuracy with a mean absolute relative residual of 8.52% in predicting experimental data with a presumption of the Langmuir–Freundlich approach for derivation and also applying fugacity instead of partial pressure in rate equations.