Perovskite-type oxide membranes for the oxidative coupling of methane
- Washington State Univ., Pullman, WA (United States). Dept. of Chemical Engineering
A series of ion-conducting perovskites of the form [La{sub 1{minus}x}A{sub x}][Co{sub 0.2}Fe{sub 0.8}]O{sub 3{minus}{delta}} (x = 0.4, 0.6 for A = Sr; x = 0.8 for A = Ba) were investigated for their use as a catalytic membrane for the oxidative coupling of methane (OCM). A-site cations consisting of La{sub 0.4}Sr{sub 0.6} and La{sub 0.2}Ba{sub 0.8} produce materials with the highest oxygen fluxes and result in C{sub 2+} selectivities of 50% at 1,098 K, which are significantly higher than those achieved with a powdered catalyst in a packed-bed reactor configuration. Selectivities in these materials appear to be limited by high oxygen ion recombination rates that compete for oxygen with the desired coupling reaction(s). The results also indicate that oxygen fluxes are not limited by diffusion, but by surface exchange rates at the oxygen-lean side of the membrane. The study on stability of these materials showed that all three perovskites could be reduced in a pure methane or ethane stream at 1,023 K, but they were totally stable under reaction conditions where oxygen is present.
- OSTI ID:
- 562244
- Journal Information:
- AIChE Journal, Journal Name: AIChE Journal Journal Issue: 11A Vol. 43; ISSN 0001-1541; ISSN AICEAC
- Country of Publication:
- United States
- Language:
- English
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