Experimental investigation and 2D mathematical modelling of copper foams packed with Rh-Al₂O₃ catalysts for the intensification of methane steam reforming

Efficient heat transfer is a crucial factor in the design of compact methane steam reformers for delocalized hydrogen production. The use of copper packed foams was proposed few years ago by our group to strongly intensify heat transfer in these systems, allowing the design of small-scale units with minimal radial temperature gradients. In this study, a new experimental campaign was performed to demonstrate the concept potential under industrially relevant heat fluxes and to establish an experimental foundation for validating a 2D mathematical model of the process. Copper open-cell foams were packed with a Rh/Al2O3 egg-shell catalyst and loaded into a 29.5 mm diameter tubular reactor, which was heated using a lab-scale oven. By leveraging the combined benefits of enhanced heat transfer, granted by the copper foam, and the high activity of the Rh-based eggshell catalyst, experiments were successfully performed at gas hourly space velocities (GHSV) ranging from 10 to 30 Nm(3)/h/kg(cat), with heat duties of up to 9 MW/m(3). These experiments lead to a methane conversion close to thermodynamic equilibrium while maintaining limited radial gradients within the system (maximum 20 degrees C across the mid-radius). A predictive pseudo-heterogeneous 2D reactor model was developed and validated against experimental data. The model accurately captured the observed trends in temperature profiles and outlet concentrations, and can be utilized for optimized design, paving the way for the development of efficient small-scale hydrogen production units.