Oxygen Permeation in Zr02-Ce02-CaO for Application to Oxygen Separation from Thermally Decomposed H20

To prepare a high-temperature oxygen permeation membrane, the enhancement of oxygen permeation rate in calu-cia-stabilized zirconia by CeO2 doping was studied. Two tube-shaped specimens (4)1.3 x 0.9 cm), 0.5 and 1.5 cm in length, were used to measure the bulk oxygen permeability from a N2 + 02 gas mixture into He, eliminating the oxygen perme-ation caused by the short-circuiting effect of Pt 0-rings which were used to seal the interface of specimens and alumina tubes. Since the oxygen source was N2 + 02, mechanical oxygen leakage was estimated from nitrogen leakage into He. From the measurement of oxygen permeations at 1100- 1800 K in [(Zr02)1_(Ce02)j09(Ca0)0.1 (X = 0.1- 1.0), it was shown that the oxygen permeability, Jr, which was normalized by the temperature and the oxygen partial pressures out-side and inside the specimen, and the electronic conductivity, which was at 1 atm of oxygen partial pressure and was cal-culated from Jr increased exponentially with temperature and X for X 0.5 while showing saturation tendency for X> 0.5. The oxygen separation membrane of K = 0.4 ' — 0.5 seems reasonable because of the remarkable permeability and lower content of CeO2 which has higher vapor pressure at high temperature. Infroduction A calucia-stabilized zirconia, CSZ, tube as high-tem-perature oxygen separation membrane was used by Cale