Methane pyrolysis in molten metal bubble column reactors (MMBCR) is a promising technology for hydrogen production with minimal CO2 emissions. This study presents a numerical model, which is computationally easy to handle, for early industrial analysis and scalability, focusing on both homogeneous and heterogeneous flow regimes. The one-dimensional model integrates thermodynamics, hydrodynamics, heat transfer, and reaction kinetics and is validated against experimental data at varying temperatures and flow rates. Simulation results indicate that the commonly assumed homogeneous flow regime in laboratory experiments may not always apply, particularly at higher temperatures and flow rates. Transitions into the heterogeneous regime were observed more frequently than expected, challenging the existing models that often neglect these conditions. Furthermore, it was found that Kassel’s kinetic model is suitable for temperatures up to 1095 °C (±5 °C), while Napier’s kinetic model provides better accuracy at higher temperatures. A detailed analysis of the key parameters was conducted to assess their influence on conversion rates. Sensitivity analysis revealed that reaction rates and gas holdup significantly affect conversions, whereas bubble diameter and heat transfer coefficients had minor effects. Thus, this study provides new insights into methane pyrolysis in MMBCRs, particularly under both homogenous and heterogeneous flow conditions.
Aliyev et al. (Sun,) studied this question.