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| Home > Publications database > Optimization of the porous support of an asymmetric oxygen transport membrane by numerical modelling |
| Conference Presentation (After Call) | FZJ-2017-07249 |
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2017
Abstract: Asymmetric oxygen transport membranes (OTM) provide a low ionic resistance of the functional separation layer together with a high mechanical stability. Hence, they are promising candidates for high-permeation in a variety of high-temperature applications for the separation of oxygen from gas mixtures. However, the microstructure of the porous support in the membrane assembly affects the overall flux significantly [1].In this work, the optimization of the porous support was studied by simulating numerically the effect of geometrical changes (pore size, pore geometry, substrate thicknesses) of the support on the overall flux, using different flow conditions (3-end, 4-end), and assembly orientation [2]. These effects were studied by applying the binary friction model (BFM) for the support together with a modified Wagner equation for the dense membrane using transport relevant parameters obtained from micro computed tomography data of a BSCF-Z support. Additionally, the effect of the support geometry and the depth of travel of the sweep gas on the permeated flux were investigated by computational fluid dynamics using Ansys Fluent. From the CFD simulation, u-shaped pores are more desirable for inverse tape cast porous support and enables quick removal of the permeated gas. Supports with elongated pores would be ideal for 4-end mode (binary diffusion limited configurations/gas mixtures e.g. membrane reactors) transport, while for oxygen generation from air (3-end), supports with either compressed or elongated pores are comparable (rel. difference < ~7%). A relationship between the opposing factors substrate thickness and pore size was developed that ensures a given flux. This can be used to optimize support’s microstructure with regards to mechanical strength and permeability. [1] P. Niehoff, et al. Oxygen transport through supported Ba0.5Sr0.5Co0.8Fe0.2O3–d membranes, Sep.Purif Technol, 121(2014)60-67.[2] U. Unije, et al. Simulation of the effect of the porous support on flux through an asymmetric oxygen transport membrane, J.Membrane Sci., 524(2017)334-343.
Keyword(s): Materials Science (2nd)
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