Fabrication of CO2-tolerant SrFe0.8Nb0.2O3-δ/SrCo0.9Nb0.1O3-δ dual-layer 7-channel hollow fiber membrane by co-spinning and one-step thermal process

CO2-tolerant membranes are crucial for oxyfuel combustion systems utilizing oxygen permeable membranes. A newly constructed dual-layer 7-channel hollow fiber membrane consisting of SrFe0.8Nb0.2O3-delta (SFN) porous outer layer and SrCo0.9Nb0.1O3-delta (SCN) hollow fiber inner layer has been successfully fabricated by co-spinning and one-step thermal process (OSTP) approach in this work. The outer layer can have different porous structures depending on the graphite content of the spinning solution. In the OSTP approach, the in-situ reactive sintering of the membrane materials results in the two layers being well adhered and mechanically robust. At 900 degrees C under 80% CO2-containing in sweeping gas, the oxygen flux of SFN/SCN dual-layer hollow fiber membrane with the porous layer of 91.8 mu m was 1.98 mL min-1 cm-2, about 7.1 times as much as the SCN hollow fiber membrane (0.28 mL min-1 cm-2) in the same situations. The porous SFN outer layer was demonstrated to prevent mem-brane performance degradation effectively. Furthermore, the SFN/SCN dual-layer membrane operated in a 20% CO2-containing atmosphere for at least 200 h, maintaining an oxygen flux of 3.20 mL min-1 cm-2 without degradation. As a result of these findings, the SFN/SCN dual-layer 7-channel hollow fiber membrane has sig-nificant application potential in CO2 capture for oxyfuel combustion.

Automated summary

A dual-layer hollow fiber membrane composed of SrFe0.8Nb0.2O3-delta and SrCo0.9Nb0.1O3-delta was successfully fabricated, which exhibited high oxygen permeability and stability under an environment with 80% CO2. It has potential application in CO2 capture for oxyfuel combustion.