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Title: 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

Abstract

The chemical stability of perovskite La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3{minus}{delta}} (LSCF-6428) has been investigated in connection with its potential use as a catalytic membrane for the oxidative coupling of methane (OCM). Once a steady-state oxygen-defect gradient is established (15--20 h), these membranes are found to be very stable under air/nitrogen gradients at temperatures up to 960 C and they respond instantaneously to temperature changes with an apparent activation energy of 159 kJ/mol. However, serious near-surface etching occurs when one side of the membrane is exposed to 100% CH{sub 4} at 850 C and atmospheric pressure, which resulted in dramatic increases in oxygen flux (a factor of 5). While this also caused an increase in the OCM reaction rate, the selectivity of C{sub 2+} hydrocarbons fell from 40 to 10%. It is also shown that stable operation under OCM conditions is possible if CH{sub 4} pressures are reduced to 0.1 atm but at a cost of C{sub 2+} production rate.

Authors:
;  [1]
  1. Washington State Univ., Pullman, WA (United States). Dept. of Chemical Engineering
Publication Date:
OSTI Identifier:
624321
Resource Type:
Journal Article
Journal Name:
Industrial and Engineering Chemistry Research
Additional Journal Information:
Journal Volume: 37; Journal Issue: 4; Other Information: PBD: Apr 1998
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 03 NATURAL GAS; 10 SYNTHETIC FUELS; LANTHANUM OXIDES; STRONTIUM OXIDES; COBALT OXIDES; IRON OXIDES; CORROSION RESISTANCE; REFORMER PROCESSES; MEMBRANES; METHANE; OXIDATION

Citation Formats

Xu, S J, and Thomson, W J. 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. United States: N. p., 1998. Web. doi:10.1021/ie970761j.
Xu, S J, & Thomson, W J. 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. United States. doi:10.1021/ie970761j.
Xu, S J, and Thomson, W J. Wed . "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". United States. doi:10.1021/ie970761j.
@article{osti_624321,
title = {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},
author = {Xu, S J and Thomson, W J},
abstractNote = {The chemical stability of perovskite La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3{minus}{delta}} (LSCF-6428) has been investigated in connection with its potential use as a catalytic membrane for the oxidative coupling of methane (OCM). Once a steady-state oxygen-defect gradient is established (15--20 h), these membranes are found to be very stable under air/nitrogen gradients at temperatures up to 960 C and they respond instantaneously to temperature changes with an apparent activation energy of 159 kJ/mol. However, serious near-surface etching occurs when one side of the membrane is exposed to 100% CH{sub 4} at 850 C and atmospheric pressure, which resulted in dramatic increases in oxygen flux (a factor of 5). While this also caused an increase in the OCM reaction rate, the selectivity of C{sub 2+} hydrocarbons fell from 40 to 10%. It is also shown that stable operation under OCM conditions is possible if CH{sub 4} pressures are reduced to 0.1 atm but at a cost of C{sub 2+} production rate.},
doi = {10.1021/ie970761j},
journal = {Industrial and Engineering Chemistry Research},
number = 4,
volume = 37,
place = {United States},
year = {1998},
month = {4}
}