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Assessment of CO2 stability and oxygen flux of oxygen permeable membranes

: Schulz, Matthias; Kriegel, Ralf; Kämpfer, Andrea


Journal of membrane science 378 (2011), No.1-2, pp.10-17
ISSN: 0376-7388
ISSN: 1873-3123
Journal Article
Fraunhofer IKTS ()
CO2 stability; oxygen; membrane; mixed conductor

Oxygen permeation measurements on Ba0.5Sr0.5Co0.8Fe0.2O3-? (BSCF), SrCo1-xNbxO3-? (SCN; x=0.1, 0.2), Sr(Co0.8Fe0.2)1-yTiyO3-? (SCFT; y=0.1, 0.2, 0.4), La2NiO4 (L2N), Ca0.5Sr0.5Fe0.2Mn0.8O3-? (CSFM) and the dual phase material Ce0.8Sm0.2O1.9+Ag (CS+Ag) were carried out using CO2/N2 mixtures as sweep gas. A breakdown of the O2 permeation was observed for BSCF and SCN even at low CO2 concentrations. A protective layer of
Ce0.8Gd0.2O1.9 on BSCF shifts the permeation breakdown to higher CO2 concentrations but was insufficient for pure CO2 sweep. SCFT samples show a stable O2 permeation with CO2 sweep, but only at temperatures of at least 900°C. The O2 permeation for CO2 sweep drops down with time, especially at lower temperatures. The time dependency was fitted by a logarithmic regression to predict the total loss of the O2 permeation.
An excellent stability against CO2 was found only for L2N, CSFM and
Cs+Ag. However, the O2 permeation values amounted to less than one order
of magnitude below BSCF.