Fraunhofer Institute for Interfacial Engineering and Biotechnology IGBWe have established a wet-spinning process for the production of asymmetric ceramic capillary membranes. Capillaries with outer diameters in the range of 0.5 to 4 mm and wall thicknesses from 50 to 500 μm are available. In a first step microfiltration membranes are obtained which can be further modified by a coating with selective layers. Beside oxide ceramics also other ceramics (e.g. SiC) and even metals (e.g. stainless steel) can be processed. Production capacities range from just a few meters on laboratory scale to pilot plant application.
If functional ceramics, like perovskites are used, dense capillary membranes can be obtained after sintering. The geometry of the capillaries can be influenced both by different spinnerets as well as spinning parameters. High oxygen permeation can be achieved by such mixed ionic and electronic conducting materials. Due to the lattice transport of oxygen in the dense material the selectivity of O2 to N2 is infinite. Therefore dense perovskite capillaries are of interest as membranes for syngas production (gas partial oxidation), as a provider for pure O2 or for the oxyfuel process.