Unsteady-state Computational Fluid Dynamics Modeling of Hydrogen Separation from H2/N2 Mixture

Abstract

3D modeling of Pd/α-Al2O3 hollow fiber membrane by using computational fluid dynamic for hydrogen separation from H2/N2 mixture was considered in steady and unsteady states by using the concept of characteristic time. Characteristic time concept could help us to design and calculate surface to volume ratio and membrane thickness, and adjust the feed conditions. The contribution of resistance between the membrane and the gas phase could be analyzed by considering characteristic times. The effect of temperature on quasi-steady time was examined at constant feed flow rate and pressure. As a result, when thickness of membrane was less than the critical amount, the surface resistance was important. According to the results, about 50% mass separation was obtained in the initial 8% period of permeation time. By enhancing temperature, membrane permeation and, consequently, hydrogen separation increased. The CFD results showed good agreement with experimental data.

Keywords

• hollow fiber membrane
• computational fluid dynamics
• hydrogen separation
• characteristic time
• unsteady state