Mechanistic Two-Phase Fluidized-Bed Reactor Model for Catalytic Methane Pyrolysis

A model of a bubbling fluidized-bed reactor for catalytic methane pyrolysis over a Fe/Al₂Oₜ catalyst is created, checked, and validated using three published experimental datasets. The model is one-dimensional and has two phases, and it follows the Kunii-Levenspiel principle. An axial energy balance, hydrogen inhibition, interphase mass transfer, gas-solid hydrodynamics, and power-law kinetics are all part of the model. The numerical verification reveals that a fourth-order Runge-Kutta solution with 200 axial nodes that is fixed-step agrees with an adaptive Dormer-Prince RK45 solution in terms of methane conversion to within 3 × 10⁻⁷, conserves energy and hydrogen to a better than 0.1% degree, and approaches thermodynamic equilibrium but never surpasses it. The model forecasts a methane conversion of 65.2% and a hydrogen mole fraction of 68.5% at the base case conditions of 900 °C, 1 bar, U₀/U_mf = 3, 2 kg catalyst, and 80% CH₄. The model predicts velocity and catalyst-loading effects that are conservative for design, but surpass the 15% acceptance requirement. It also accurately reproduces calibrated temperature effects within 5% and the direction of all trends versus three literature fluidized-bed datasets. Methane pyrolysis reactors can be physically optimised, surrogate models can be used, and uncertainty can be quantified with this approach