(99c) Purifying Hydrogen with Inorganic Silica Membranes at High Temperatures

The recent demand for pure hydrogen has driven researchers to develop technologies for this application from the laboratory to industrial scales. Inorganic membrane technology is fast becoming viable candidate for hydrogen purification for its simplicity and continuous operation mode. In our work, we developed a composite silica membrane exhibiting high selectivity of H2 over CO2, N2 and CO from commercially available substrates. Permeation of each gas was activated and followed the order of molecule size, supporting the molecular sieving theory. Tests at 300°C showed H2 permeation and H2/N2 selectivity of 1.75 × 10-7 mol.m-2.s-1.Pa-1 and 48 respectively. Process modelling at 300°C with a synthetic reformate gas fed at 5 bar to the feed and exiting at 1 bar increased H2 by 20 vol% in a single stage with 0.8 m2 of membrane area for 1 slm reformate feed flow. Silica membranes are therefore suitable for H2 enrichment in either one or two stages. Major challenges in future work are developing high surface area membrane modules.