Reaction Mechanism Development for Methane Steam Reforming on a Ni/Al2O3 Catalyst

Abstract

In this work, a reliable kinetic reaction mechanism was revised to accurately reproduce the detailed reaction paths of steam reforming of methane over a Ni/Al2O3 catalyst. A steady-state fixed-bed reactor experiment and a 1D reactor catalyst model were utilized for this task. The distinctive feature of this experiment is the possibility to measure the axially resolved temperature profile of the catalyst bed, which makes the reaction kinetics inside the reactor visible. This allows for understanding the actual influence of the reaction kinetics on the system; while pure gas concentration measurements at the catalytic reactor outlet show near-equilibrium conditions, the inhere presented temperature profile shows that it is insufficient to base a reaction mechanism development on close equilibrium data. The new experimental data allow for achieving much higher quality in the modeling efforts. Additionally, by carefully controlling the available active surface via dilution in the experiment, it was possible to slow down the catalyst conversion rate, which helped during the adjustment of the reaction kinetics. To assess the accuracy of the revised mechanism, a monolith experiment from the literature was simulated. The results show that the fitted reaction mechanism was able to accurately predict the experimental outcomes for various inlet mass flows, temperatures, and steam-to-carbon ratios.

A Review on the Use of Catalysis for Biogas Steam Reforming

“…There are other possible side reactions, like a direct reaction between CH 4 and CO 2 , CH 4 and CO, and methane decomposition, etc. These side reactions are more abundant if heterogeneous catalysts are used in the process [28,29]. The production of H 2 depends on the equilibrium of the reforming and adjustment reactions (Equations ( 1) and ( 2)), and it can be maximized with low pressures, high temperatures in reforming, and a high excess of steam [30,31].…”

Analytical and Numerical Thermodynamic Equilibrium Simulations of Steam Methane Reforming: A Comparison Study

“…The SMR reaction typically occurs at elevated temperatures (900-1200 K) and pressures (5-25 bar) [6,9], with a preference for high temperatures and low pressures. Due to the production of high concentrations of carbon monoxide (CO) in the reaction products, the SMR process is inherently coupled with the water-gas shift reaction (WGS) (2).…”