Autothermal Reforming of Methane with Integrated CO2 Capture in a Novel Fluidized Bed Membrane Reactor. Part 2 Comparison of Reactor Configurations

The reactor performance of two novel fluidized bed membrane reactor configurations for hydrogen production with integrated CO₂ capture by autothermal reforming of methane (experimentally investigated in Part 1) have been compared using a phenomenological reactor model over a wide range of operating conditions (temperature, pressure, H₂O/CH₄ ratio and membrane area). It was found that the methane combustion configuration (where part of the CH₄ is combusted in situ with pure O₂) largely outperforms the hydrogen combustion concept (oxidative sweeping combusting part of the permeated H₂) at low H₂O/CH₄ ratios (<2) due to in situ steam production, but gives a slightly lower hydrogen production rate at higher H₂O/CH₄ ratios due to dilution with combustion products. The CO selectivity was always much lower with the methane combustion configuration. Whether the methane combustion or hydrogen combustion configuration is preferred depends strongly on the economics associated with the H₂O/CH₄ ratio.