Separation of bulk carbon dioxide-hydrogen mixtures by selective surface flow membrane

The separation performance of carbon dioxide-hydrogen mixtures by a nanoporous carbon membrane called selective surface flow membrane is described. The membrane selectively permeates CO2 from H-2 and a H-2 enriched gas is produced at the feed gas pressure. Extensive experimental data for the separation using feed gas pressures from 0.24 to 1.13 MPa and CO2 compositions from 5 to 75 (mol%) in H-2 are reported. The data can be empirically correlated using a simple equation with a single adjustable-parameter. The adjustable parameter is found to be a linear function of the feed gas CO2 partial pressure. The membrane separates CO2-H-2 mixture very efficiently even at a low total feed gas pressure (similar to 0.4 MPa). The membrane area required for a given separation decreases drastically with increasing feed gas pressure in the range of 0.24-0.92 MPa and then it becomes insensitive to the feed gas pressure.