MANUFACTURING AND PERFORMANCE OF SUPPORTED BSCF-MEMBRANES FOR OXYGEN SEPARATION

摘要

Oxygen transport membranes present a promising alternative to the widely used cryogenic air separation for the generation of oxygen. Especially ceramic membranes made of perovskites show high oxygen flux and purity, leading to advanced research in optimization, module design and manufacturing. This work is investigating the manufacturing and oxygen transport through planar membranes made of Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-σ). Disc shaped samples were fabricated by means of tape casting, consisting of gas tight membrane layers with varying thickness and porous support layers for mechanical strength. The microstructure was analyzed using SEM and X-ray computer tomography with regard to characteristic values (porosity, tortuosity, and specific surface area). These results combined with literature approaches were used as a basis for a model concept, extending the Wagner equation to account for born bulk transfer and surface exchange kinetics. Permeation measurements with varying operating conditions were carried out and used to validate the model approach. Good agreement was found in case of constant porosity and adjusted characteristic thickness. A basic design approach for a modular system is presented, consisting of gastight planar multilayer compounds intended for 3-end operation. The manufacturing of components via tape lamination and the joining and sealing of the components is discussed.