Bjørnetun Haugen, Astri

Gurauskis, Jonas

Hendriksen, Peter Vang

Kaiser, Andreas

Ovtar, Simona

Online Research Database In Technology

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Dec 21, 2017Fabrication of porous 3-YSZ turbular supports for oxygen transport membranesBjørnetun Haugen, Astri; Gurauskis, Jonas; Ovtar, Simona; Hendriksen, Peter Vang; Kaiser, AndreasPublication date:2015Document VersionPeer reviewed versionLink back to DTU OrbitCitation (APA):Bjørnetun Haugen, A., Gurauskis, J., Ovtar, S., Hendriksen, P. V., & Kaiser, A. (2015). Fabrication of porous 3-YSZ turbular supports for oxygen transport membranes. Abstract from Summer school on Ionic and protonicconducting ceramic membranes for green energy applications, Valencia, Spain.FABRICATION OF POROUS 3-YSZ TUBULAR SUPPORTS FOR OXYGEN TRANSPORT MEMBRANES   Astri Bjørnetun Haugen, Jonas Gurauskis, Simona Ovtar, Peter Vang Hendriksen and Andreas Kaiser Department of Energy Conversion and Storage, Technical University of Denmark Frederiksborgvej 399, DK-4000, Roskilde, Denmark Email: ahua@dtu.dk  Keywords: Oxygen transport membrane, Extrusion, Porosity, YSZ    Pure oxygen gas supplied by ceramic oxygen transport membranes can facilitate reduced CO2 emissions through more efficient gasification processes, partial oxidation reactions and CO2 capture and storage. Tubular membranes have some advantages compared to planar membranes, such as better resistance to thermal gradients and a more straightforward sealing. The active oxygen separation layer in the membrane should be as thin as possible and therefore supported on a highly porous tubular substrate. The aim of this project is to produce oxygen transport membrane components for inte-gration in a biomass gasifier. A component has been developed that consists of a 3 mol% yttria-stabilized zirconia (3-YSZ) porous support, dense Sc2O3-doped YSZ + Al2O3-doped ZnO as the composite membrane, and porous Sc2O3-doped YSZ infiltration layers on each side of the dense membrane. The requirements for the porous 3-YSZ support are gas permeability of 10-14 m2, mechanical strength of 50 MPa and sufficient sintering shrinkage for densification of the membrane layer.   This work focuses on the manufacture of tubular porous supports of 3 mol% yttria-stabilized zirconia using thermo-plastic extrusion. Two types of poreformers (spherical graphite (d50 18 µm) and polymethyl methacrylate (PMMA, d50 10 µm)) have been used as sacrificial fugitives to form connected macropores, since their spherical geometry limits preferential orientation during extrusion. Their difference in decomposition temperatures also allows a high volume fraction of pore formers without deformation during de-binding. The influence of the amount of pore formers (relative to the amount of ceramic and thermoplastics) on the microstructure of sintered samples, as well as the extrudability and ease of de-binding of the feedstock, has been studied. Combining both spherical graphite and PMMA pore formers was necessary to obtain the highest permeability and a feedstock with a viscosity suitable for extrusion. Ceramics with 1-20 µm pore size, pore neck size up to 1.2 µm, open porosities exceeding 55 % and gas permeabilities exceeding 10-14 m2 were then produced (Figure 1). Poor connectivity and small pore neck size is the main limitation for the pore connectiv-ity and therefore also the gas permeability. Still, these results demonstrate that porous tubes with sufficient gas permea-bility can be fabricated by thermoplastic extrusion.     Figure 1. Microstructure of the most permeable 3-YSZ feedstock composition after sintering at 1300 ˚C. Left: cross-sectional view demonstrating a homogeneous porous structure. Right: High magnification of the microstructure demonstrating spherical pores from PMMA pore formers and elongated pores from spherical graphite pore formers.   

Fabrication of porous 3-YSZ turbular supports for oxygen transport membranes

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Fabrication of porous 3-YSZ turbular supports for oxygen transport membranes

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