Cermet membranes were prepared by conventional ceramic processing and fabrication techniques.  Using several feed gas mixtures, we measured the nongalvanic hydrogen permeation rate, or flux, for the cermet membranes in the temperature range of 500-900°C. This rate varied linearly with the inverse of membrane thickness and reached ≈33 cm³[STP]/min-cm² at 900°C for an ≈15-micron-thick membrane on a porous support structure when 100% H₂ at ambient pressure was used as the feed gas. Good chemical stability is a critical requirement for membranes separating hydrogen from the product streams of coal gasification and/or methane reforming.  When cermet membranes were tested in a gas mixture that contained high concentrations of CH₄, CO, and CO₂ for times that approached ≈500 h, performance did not degrade.  Because HTMs will encounter H₂S, we also tested the cermet membranes in gas mixtures containing H₂, CH₄, CO₂, CO, and H₂S.  Hydrogen flux measurements showed that  the cermet membranes are stable at 900°C for up to 1200 h in gases that contain 400 ppm H₂S.  The cermet membranes are found to be stable in the temperature range of 500 - 800°C in simulated synthesis gas mixtures containing ≈21% steam. To be practical, HTMs must have good mechanical integrity at high temperature (≈900°C) and high pressure (>300 psig).  We have recently constructed a reactor that allows the hydrogen flux of membranes to be measured at temperatures up to 900°C and pressures up to 300 psig. The present status of membrane development at Argonne and the challenges involved in bringing this technology to fruition will be presented in this talk.

Work supported by the U.S. Department of Energy, Office of Fossil Energy, National Energy Technology Laboratory’s Hydrogen and Syngas Technology Program, under Contract DE-AC02-06CH11357.