Hydrogen can be purified and carbon dioxide can be separated from their gas mixtures in a palladium (Pd) membrane tube. To figure out the hydrogen permeation characteristics in a non-isothermal Pd membrane tube, a numerical method is developed. The influence of the Reynolds numbers at the retentate and permeate sides, the temperatures of feed gas and sweep gas, and the H2concentration in the feed gas on the interfacial H2permeation and H2recovery are analyzed. The results indicate that the minimum H2partial pressure difference and permeation rate along the membrane surface develops, as a consequence of competition between the membrane permeance and the H2partial pressure difference. A dimensionless mass transfer parameter (ξ), which is a non-dimensional driving force ratio between H2diffusion in the gas phase and H2permeation across the membrane, is conducted to aid in illustrating the mass transfer characteristics along the membrane surface. The ξ curve is insensitive to the Reynolds numbers, but depends significantly on interfacial temperature and H2inlet concentration. When the H2inlet concentration is low, all H2in the feed gas can be recovered and the minimum distribution no long appears. This also implies that all CO2is separated.
All Science Journal Classification (ASJC) codes
- Environmental Chemistry
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering