Hydrodynamics of CH4-Sn molten-metal bubble columns under electromagnetic field using computational fluid dynamics

Abstract

The use of molten metal bubble column reactors (MMBCRs) for CO2-free H2 production via non-oxidative CH4 pyrolysis has gained attention due to little catalyst deactivation and simple downstream processing. Maintaining a small size of bubbles is crucial to enhance CH4 decomposition rates in MMBCRs. In this study, the effect of electromagnetic field on the hydrodynamics of MMBCRs was investigated using volume-of-fluid computational fluid dynamics (VOF-CFD) coupled with a large-eddy simulation (LES) model for turbulence and a magnetohydrodynamic (MHD) model for the electromagnetic field. Hydrodynamic parameters such as the gas holdup (αG), mean bubble size (d32), and gas–liquid interfacial area (as) were obtained from the validated VOF-CFD model in the bench-scale CH4-Sn system at 900 °C. A horizontal electromagnetic field with alternating current (AC) at an electromagnetic field strength of 1.0 T promoted bubble breakup and increased as from 8.6 to 18.2 m2/m3 compared to the MMBCR without electromagnetic field.