Elaboration of La1-xSrxFe1-yGayO3-' multilayer membrane by tape-casting and co-firing
Résumé
The catalytic membrane reactor (CMR) is a promising solution for the production of fuel from natural gas, via gas to liquid process (GTL). This reactor allows to produce syngas from natural gas in a single step. The main element of this technology is the ceramic membrane, which, on the one hand, separates oxygen from air and, on the other hand, leads to the partial oxidation of methane from natural gas in hydrogen and carbon monoxide. The CMR performances, for partial oxidation of methane, mainly depend on the oxygen semi-permeation properties of membrane materials and on the membrane design. This study implies the elaboration of optimal membrane design in terms of oxygen semi-permeation performances and thermo-mechanical properties in working conditions. The design consists in a crack free La0.8Sr0.2Fe0.7Ga0.3O3-δ dense thin film with a porous support layer on oxiding faces and porous catalytic layer on reducing faces. This multilayer membrane could be the best compromise for oxygen semi-permeation performance and thermo-mechanical properties. Then, this work presents the elaboration by tape casting lamination and co-firing process of a membrane consisting of a multilayer design of La1-xSrxFe1-yGayO3-δ dense or porous layer. In order to avoid membrane cracking during the sintering and under working conditions, the material of the multilayer was identified and adapted to have the same shrinkage during the co-firing and a thermal expansion coefficient similar to the membrane material. This study gives the main keys of the development of multilayer membrane. Finally, we show that this membrane design leads to an enhancement of the oxygen semi-permeation flux compared to traditional membranes and with excellent thermo-mechanical properties in working conditions.