Hydrogen Separation from Reforming Products by Silica Membrane: A Numerical Study

In this paper, a 2D axisymmetric computational fluid dynamics (CFD) model is presented for the process of hydrogen separation from reforming products by silica membrane. This model has the capability of showing selective permeance of species through membrane, as a preference to pervious works. In this work, effects of temperature, pressure difference, and feed inlet velocities on species molar fraction, silica membrane performance were investigated. For this purpose, ternary mixture of H2 /CO2 /CO with percentages of 69/30/1 was chosen, and flow rate of 120 (mL/min) was considered as feed. As temperature increased from 323.15 K to 373.15 K, hydrogen molar fraction at the outlet of feed side decreased from 62.44 to 51.06, and at the outlet of permeate side, increased from 78.32 to 80.82. Increase in pressure difference led to reduction of molar fraction for hydrogen and increase for other components at permeate side. At retentate side, hydrogen molar fraction was reduced with pressure difference rise, from 1 to 3 bar, while for 3 to 4 bar it increased. Increasing the feed inlet velocity from 5.99 to 8.29 mm/s resulted in hydrogen molar fraction rise from 30.17 to 37.71 at retentate side and from 77.03 to 82.52 at permeate side. Therefore, silica membrane operated more effectively at higher temperatures, lower pressure differences, and mean velocities