CFD evaluation of a microchannel reactor for ammonia synthesis using a Ruthenium-based catalyst

This work evaluates the potential of microchannel reactors (MCR) for ammonia synthesis using ruthenium-based catalysts through computational fluid dynamics (CFD) modelling. A comprehensive CFD framework was developed that integrates mass and energy balances with modified Temkin-Pyzhev kinetics, and validated against experimental data from a packed-bed reactor (PBR) with <5 % error. The validated model was then applied to MCR configurations to assess the influence of operating conditions and reactor geometry. Results show that MCRs achieve up to 165 % higher ammonia productivity than PBRs under optimal conditions (100 bar, 430 °C), owing to the enhanced heat and mass transfer. Parametric studies identified temperature as the most critical operating parameter, while pressure had a secondary effect. Furthermore, increasing the catalytic layer thickness improved ammonia yields, although there are potential mass-transfer limitations. These findings demonstrate that MCRs can provide significant energy-efficiency gains and support decentralised ammonia production, highlighting their promise as a sustainable alternative to conventional Haber-Bosch technology.