Analysis of dry reforming of methane under different fluidization regimes using a multiphase particle-in-cell approach

In the present study, the dry reforming of methane (DRM) has been simulated in fluidized-bed reactors using the multiphase particle-in-cell model. The model was meticulously built to investigate the effect of a wide range of superficial gas velocities covering particulate, aggregative, and lean-phase flow regimes on bed hydrodynamics, conversion, and yields of product gases. Constant values for catalyst loading, CH4:CO2:N2 ratio (1:1:1.3), and catalyst and gas properties were maintained in all simulations. The simulation results obtained are in good agreement with the experimental data reported in the literature. The results show that under different gas velocities, conversion is relatively indiscernible in the particulate regime. In contrast, for the inhomogeneous phases, the turbulent-fluidized bed had the best reactor performance with high CH4 and CO2 conversion rates, good CO + H2 productivity, and high CO/H2 molar ratio. This is due to the vigorous turbulent flow and relatively high gas-solid contact. Due to gas bypassing and backmixing triggered by bubbling, the bubbling-fluidized bed generally had the worst performance and below that of the fast-fluidized bed. The present study demonstrates that the performance of DRM reactions in fluidized-bed reactors is strongly related to the hydrodynamics. Moreover, it shows the significance of gas velocity on DRM conversion, yield, and overall reactor performance.