Computational Modeling of Methane Pyrolysis in a Fixed-Bed Reactor for CO₂-Free Hydrogen Production

Methane pyrolysis, a catalytic route for carbon dioxide-free hydrogen production, relies on complex interactions between fluid dynamics, species transport, and reaction kinetics within porous catalytic media. In this computational investigation, we utilize ANSYS Fluent to simulate methane decomposition in a fixed-bed reactor at low Reynolds number flow conditions. The reactor bed is represented as a porous zone, integrating species transport and reaction kinetics through a global Arrhenius mechanism obtained through kinetic experiments in a similar reactor. The numerical model is validated against the Ergun equation for pressure drop across varying inlet velocities. Particular attention is given to simulations at low inlet velocities (~0.005 m/s), ensuring adequate residence time for catalytic conversion and agreement with the experimental setup. Results provide spatially resolved insights into methane conversion, temperature distributions, and hydrogen yield, offering fundamental understanding towards the optimization and scale-up of catalytic pyrolysis reactors.