Temperature Dependence of Cr Impurity in La0.6Sr0.4Ti0.3Fe0.7O3-delta Coated Ba0.5Sr0.5Co0.8Fe0.2O3-delta Ion Conducting Membrane for oxygen Separation

Abstract

La0.6Sr0.4Ti0.3Fe0.7O3-delta(LSTF) coated Ba0.5Sr0.5Co0.8Fe0.2O3-delta(BSCF) membranes which has properties of high oxygen permeability and stability to CO2 were applied to a bench scale apparatus to conduct oxygen permeation experiments. Also, the membranes of the laboratory and the bench scale device were divided into three regions according to the temperature gradient in the membrane reactor for comparative analysis. While oxygen permeation experiment were conducted up to 900 degrees C, temperature dependence of Cr deposition was investigated. As a result, it was confirmed that the oxygen permeability was 2.37 ml/min.cm(2), which was significantly lower than 3.79 ml/min.cm(2) measured in the laboratory apparatus. It was found through XRD and SEM/EDS analysis that the decrease in oxygen permeability was originated from the deposition of gaseous Cr on the membrane surface released from the alloy material of the housing. In particular, a large amount of Cr was found in the medium temperature region.