Mixed-conducting oxides for gas separation applications.
Mixed-conducting oxides are attracting increased attention because of their potential uses in high-temperature electrochemical applications such as solid-oxide fuel cells, batteries, sensors, and gas-permeable membranes. We are developing mixed-conducting, dense ceramic membranes to selectively transport oxygen and hydrogen. Ceramic membranes made of Sr-Fe-Co oxide (SFC), which exhibits high combined electronic and oxygen ionic conductivities, can be used to selectively transport oxygen during the partial oxidation of methane to synthesis gas (syngas, a mixture of CO and H{sub 2}). Steady-state oxygen permeability of SrFeCo{sub 0.5}O{sub x} has been measured as a function of oxygen-partial-pressure gradient and temperature. At 900 C, oxygen permeability was {approx}2.5 scc{center_dot}cm{sup {minus}2}-min{sup {minus}1} for a 2.9-mm-thick membrane, and this value increases as membrane thickness decreases. We have fabricated tubular SrFeCo{sub 0.5}O{sub x} membranes and operated them at 900 C for >1000 h during conversion of methane into syngas. Yttria-doped BaCeO{sub 3} (BCY) is a good protonic conductor; however, its lack of electronic conductivity can potentially limit its hydrogen permeability. To enhance the electronic conductivity and thus improve hydrogen permeation, a membrane composite material was developed. Nongalvanic permeation of hydrogen through the composite membrane was characterized as a function of thickness.
- Research Organization:
- Argonne National Lab., IL (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 11187
- Report Number(s):
- ANL/ET/CP-98000
- Country of Publication:
- United States
- Language:
- English
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Development of mixed-conducting oxides for gas separation
Development of mixed-conducting ceramics for gas separation applications.