Towards hydrogen production by methane pyrolysis in a microwave-assisted fluidized bed reactor: Hydrodynamics of a catalytic fluidized bed and 1D convection-dispersion modelling

This study investigates the minimum fluidization velocity ($U_{mf}$) of Fe/C catalyst and presents preliminary modelling results for a microwave-assisted fluidized bed reactor (MAFBR). The hydrodynamics was examined experimentally and through a Discrete Element Method-Computational Fluid Dynamics (DEM-CFD) modelling approach. A satisfactory agreement was observed between the experimentally determined $U_{mf}$ and the value predicted by the model, which assumed a spherical shape for Fe/C catalyst particles as a simplification. Further testing of the model using reference glass beads highlighted the importance of incorporating particle shape factors and particle size distribution for improved accuracy. The model also demonstrated good performance when applied to a mixture of two different glass bead fractions. Additionally, MAFBR modelling was conducted using an axially dispersed plug flow model, incorporating a CH₄ pyrolysis rate equation for the Fe/C catalyst formulated in our previous work [1]. The model provided insight into FBR behaviour under varying conditions including temperature, catalyst mass and methane flow rate. Such approach provides basis for the MAFBR design.