Abstract
Mixed ionic-electronic conducting 3, 4, 7-bore capillary membranes made of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) were successfully prepared by the combined phase inversion/sintering technique. The membranes fabricated have asymmetric wall structures with micro-channels formed in between surfaces, and dense layers sandwiched in between the micro-channels. By changing the solvent from DMSO to NMP, changes in the morphology of the 7-bore membrane were observed, where the separation layer has reduced its effective thickness. The multi-bore membranes exhibited 3-point bending fracture loads of 10.4, 13.5, 15.4 and 11.7 N with a 3cm testing span for the 3-bore, 4-bore, 7-bore-DMSO and 7-bore-NMP samples, respectively, which are much stronger than single-bore hollow fibre membranes. Oxygen permeation of the multi-bore membranes was measured with a sweep gas flow through lumen and the effect of operating temperature has on the performance was studied between 750°C to 1000°C. Oxygen fluxes measured are comparable to typical sandwich-like structured single-bore hollow fibres at temperatures below 900°C, but are notably higher at higher temperatures owe to their thinner membrane walls. The 200-h long-term permeation test conducted on the 7-bore membrane showed a slight increase in permeation flux, but the sign of kinetic demixing/decomposition appeared on the outer surface, where the surface of the thinnest membrane walls underwent faster demixing/decomposition than the thickest walls. In summary, the results demonstrated that multi-bore configurations can achieve optimised material distribution during the fabrication, and can obtain strong mechanical property, high permeation flux for the final products whilst maintaining high membrane area to volume ratios.
Highlights
Oxygen production is of great importance in industrial and environmental processes
Our previous study has shown successful preparation of 3, 7, 19bore porous capillary membranes made of alumina using the combined phase-inversion and sintering method [22], and they showed much improved mechanical property, and enhanced water permeation flux compared with their single-bore hollow fibre counterparts
We show here that different from conventional ram extrusion, by adjusting fabrication parameters in the phase-inversion process, the morphology of multi-bore membranes can be notably altered
Summary
Oxygen production is of great importance in industrial and environmental processes. Current technologies such as the cryogenic distillation and pressure swing adsorption (PSA) are expensive and energy intensive. The requirement of onestep continuous production has led to the recent interest in fabricating multi-bore capillary membranes [18,19,20,21] Results obtained from such configurations showed some promising results where they exhibited an improved mechanical property with good oxygen permeation flux for the 4-bore membranes. Our previous study has shown successful preparation of 3, 7, 19bore porous capillary membranes made of alumina using the combined phase-inversion and sintering method [22], and they showed much improved mechanical property, and enhanced water permeation flux compared with their single-bore hollow fibre counterparts. The mechanical property and oxygen permeation flux for the multi-bore LSCF membranes are studied, and the long-term 200 h test on stability and kinetic demixing/decomposition are investigated with the 7-bore membrane
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
