Capturing CO2 at point sources such as power plants or cement manufacturing plants is one of the alternatives to reduce the CO2 exhaust by industrial activities. At this moment, capturing processes are not yet economically viable. One of the main reasons is that for efficient capture, the plant has to be fired with pure oxygen instead of nitrogen to prevent the formation of large quantities of NOx. On an industrial scale, the most attractive process to supply pure oxygen is cryogenic distillation. The energy demand of the required cooling is huge. As an alternative, the use of dense ceramic membranes is investigated.
Materials with a perovskite- or spinel crystal structure can be doped with cations that have a different valency than the native cation. In this way, oxygen vacancies can be created in the crystal structure; thereby providing oxygen transport properties to the membrane material. Both the oxygen exchange reactions and the bulk diffusion could have an impact on the oxygen diffusion through the membrane. In this research, analysis techniques such as electronic conductivity relaxation (ECR) are used to dive into the fundamentals of the processes that take place with the oxygen permeation. Characterization methods such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and X-ray Photoelectron Spectroscopy (XPS) can be employed to get insight in the crystal structure on a molecular level.
The main topics of interest in this project are the stability and permeability of the ceramic materials in an oxyfuel environment (T=850°C, presence of CO2, H2O, and SO2).