Catalytic properties of oxygen semipermeable perovskite-type ceramic membrane materials for oxidative coupling of methane
- Univ. of Cincinnati, OH (United States)
The catalytic properties for the oxidative coupling of methane (OCM) of La{sub 0.8}Sr{sub 0.2}CoO{sub 3} (LSC) and SrCo{sub 0.8}Fe{sub 0.2}O{sub 3}(SCF) in solid solution were studied and compared with those of 5 wt% Li/MgO, using a steady/unsteady state packed-bed reactor and a transient microbalance. The results of the steady-state cofeed experiments show that LSC possesses OCM catalytic properties similar to those of Li/MgO in terms of C{sub 2} yield and selectivity at temperatures of around 800 C. The former gives a larger C{sub 2} space time yield than the latter. SCF exhibits poor OCM catalytic properties at 700-850{degrees}C. To further examine the suitability of LSC as a membrane material for use in a dense membrane reactor for OCM, the instant OCM selectivity and activity and oxygen consumption rate for LSC and 5% Li/MgO on exposure to pure methane in cyclic feed mode were measured respectively at 850{degrees}C and 800{degrees}C. For both materials, the unsteady-state cyclic feed operation gives a smaller initial OCM activity and larger initial C{sub 2} selectivity than the cofeed steady state operation. Li/MgO quickly loses its OCM activity and selectivity in the unsteady state operation due to rapid consumption of the active sites. Up to 5 min of methane run time, LSC maintains appreciable OCM activity with poorer C{sub 2} selectivity as compared to the steady state cofeed operation. The surface of LSC membrane at low oxygen partial pressure may become nonselective for OCM in membrane reactor applications. 48 refs., 12 figs., 4 tabs.
- OSTI ID:
- 486390
- Journal Information:
- Journal of Catalysis, Vol. 164, Issue 1; Other Information: PBD: Nov 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Stability of La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3{minus}{delta}} perovskite membranes in reducing and nonreducing environments
Dense perovskite membrane reactors for partial oxidation of methane to syngas