Modeling of H₂ Permeation through Electroless Pore-Plated Composite Pd Membranes Using Computational Fluid Dynamics.

Area of Science:

• Chemical Engineering
• Materials Science
• Computational Modeling

Background:

• Efficient hydrogen separation is crucial for various industrial processes, including ammonia synthesis and fuel cells.
• Palladium-based membranes offer high selectivity for hydrogen but require accurate modeling for optimal performance.
• Computational fluid dynamics (CFD) provides a powerful tool for simulating complex separation processes.

Purpose of the Study:

• To develop and validate a CFD model for H₂/N₂ separation in a supported dense Pd-based membrane permeator.
• To investigate the influence of operating conditions on hydrogen separation efficiency.
• To provide insights for the design and optimization of membrane reactors.

Main Methods:

• A CFD model was developed using a source-sink pair formulation for species transport and continuity equations.
• The model incorporated the Darcy-Forcheimer formulation for the porous stainless steel support and Sieverts' law for H₂ permeation.
• Simulations were performed for two reactor configurations (in-out and out-in) under various operating conditions.

Main Results:

• The CFD model demonstrated excellent agreement with experimental data for permeate and retentate flows and H₂ separation.
• Simulations accurately predicted the impact of feed pressure and H₂ concentration on separation performance.
• Concentration polarization was identified as non-limiting for H₂ permeation but useful for reactor length optimization.

Conclusions:

• The developed CFD model is a reliable tool for simulating H₂/N₂ separation in Pd-based membrane permeators.
• The model's predictions can guide the optimization of operating parameters and reactor design for enhanced hydrogen separation.
• Understanding concentration polarization effects aids in designing more efficient membrane reactors.