Industrial & Engineering Chemistry Research, Vol.60, No.2, 851-863, 2021
Kinetic Modeling of Combined Steam and CO2 Reforming of Methane over the Ni-Pd/Al2O3 Catalyst Using Langmuir- Hinshelwood and Langmuir-Freundlich Isotherms
Combined steam and CO2 reforming of methane (CSCRM) testing was used to determine the responses of CH4 conversion, H-2 and CO yield, and CO2 conversion at a temperature range of 500-1000 degrees 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, H-2 chemisorption, and O-2-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 H-2 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.