Oxygen permeation through asymmetric perovskitic membranes
|Michael Betz , Stefan Baumann , Wilhelm A. Meulenberg , Detlev Stoever|
Forschungszentrum Jülich, Institute of Energy Research IEF (FZJ-IEF), Leo-Brandt-Strasse, Jülich 52425, Germany
The necessity of reducing CO2-emissions is evident and getting more and more social consensus all over the world. Therefore, carbon capture and storage (CCS) is an important option in order to achieve CO2 mitigation. One of three options for CCS is making use of oxyfuel technology, where pure oxygen is used to combust a fuel (e.g. coal, gas, biogas) forming primarily CO2 and H2O making it much easier and cheaper to capture the CO2 than by using air in the combustion. The required oxygen can be produced using ceramic oxygen transport membranes (OTM), which are associated with significantly lower efficiency losses compared to conventional separation technologies. OTM consist of gastight mixed ionic electronic conductors (MIEC), which allow oxygen diffusion through vacancies in the crystal lattice and simultaneous transport of electrons in the opposite direction at elevated temperatures, e.g. 800-900°C. Their major advantage is infinite oxygen selectivity, assuming no leakage through the membrane layer or the sealing. Highest oxygen permeation can be obtained using perovskite materials (ABO3) such as (Ba,Sr)(Co,Fe)O3 or (La,Sr)(Co,Fe)O3. In order to further increase permeation rates, asymmetric thin film membranes with activated surfaces are necessary. The preparation of asymmetric multi-layered membrane assemblies is presented. Furthermore, characterization results, e.g. SEM-micrographs, permeation data, are shown, and challenges and prospects are derived. It is shown that permeation rates increase using asymmetric membrane, but the increase is relatively low due to surface exchange kinetics and gas diffusion through porous support.
Presentation: Oral at E-MRS Fall Meeting 2009, Symposium G, by Michael Betz
See On-line Journal of E-MRS Fall Meeting 2009
Submitted: 2009-05-05 14:58 Revised: 2009-06-10 15:12