One-dimensional kinetic model with heat transfer and axial dispersion of molten-metal bubble column reactors for hydrogen production via methane pyrolysis

Abstract

A one-dimensional (1D) molten-metal-based bubble-column reactor (MMBCR) model coupled with heat transfer and axial dispersion was developed for non-oxidative CH4 pyrolysis to produce low-carbon H2. The MMBCR model included mass, momentum, and energy balances, accounting for catalytic and non-catalytic reaction kinetics, and hydrodynamic parameters such as the gas holdup (αG), gas velocity (uG), bubble size (db), and specific interfacial surface area of bubbles (as). The 1D MMBCR model was compared with other 1D reactor models and bench-scale experimental data for CH4 conversion (XM). The MMBCR model agreed well with the experimental data. When heat transfer and axial dispersion were considered for an industrial-scale MMBCR to produce 10,000 Nm3/h, the reactor length increased to 2.4 times higher than that estimated by the model without axial dispersion to meet 80% XM. The MMBCR model has the potential to design industrial-scale MMBCRs and optimize operating conditions.