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

A one-dimensional (1D) molten-metal-based bubble-column reactor (MMBCR) model coupled with heat transfer and axial dispersion was developed for non-oxidative CH 4 pyrolysis to produce low-carbon H 2. 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 (α G), gas velocity (u G), bubble size (d b), and specific interfacial surface area of bubbles (a s). The 1D MMBCR model was compared with other 1D reactor models and bench-scale experimental data for CH 4 conversion (X M). 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% X M. The MMBCR model has the potential to design industrial-scale MMBCRs and optimize operating conditions. [Display omitted] • One-dimensional molten metal-based bubble column reactor (MMBCR) model was developed. • MMBCR model for CH 4 pyrolysis was coupled with heat transfer and axial dispersion. • Heat transfer and axial dispersion slightly affect bench-scale MMBCRs CH 4 conversion. • Axial dispersion lowered the CH 4 conversion of an industrial-scale MMBCR by 17%. • The MMBCR model is useful to design the reactors and optimize operating conditions. [ABSTRACT FROM AUTHOR]