Oxygen selective perovskite hollow fiber membrane bundles

Abstract

Perovskite ceramic hollow fiber membranes (HFMs) have attracted great interest due to their potential application as the novel cost-effective method for oxygen production and favorable features for compact module preparation. However, the practical application of these perovskite HFMs is limited by the inherent brittleness of ceramic material and in cases of thick fiber wall, the insufficient oxygen flux values. In this work, highly asymmetric BaCo0.85Bi0.05Zr0.1O3-δ (BCBZ) perovskite HFMs with a thin dense separation layer supported on the porous BCBZ substrate were fabricated by a modified phase inversion-sintering technique. The perovskite HFMs were integrated in a porous BCBZ perovskite matrix to form a bundle structure to simultaneously achieve high mechanical strength for membrane assembly and high O2 permeation rate. Pure O2 was achieved from air separation by vacuuming the permeate side of the hollow fiber bundles (HFBs). Oxygen recovery rate is a function of multi-factors including operation temperature, air feeding flow rate and the membrane area provided by the HFBs. The thermal cycle and post characterization results of the spent HFBs highlight the good stability of the fabricated HFBs. Oxygen permeation rate increased with the HFM number in the HFBs. Under static air atmosphere and the operation mode of vacuum application, the permeation rate of HFBs containing 3 HFMs (HFB_3) or 7 HFMs (HFB_7) at 1000 °C was 79.01 or 98.12 mL min−1, respectively. Normalized by the overall membrane area, the achieved oxygen flux for HFB_3 or HFB_7 was 13.27 or 7.06 mL cm−2 min−1, respectively, the difference of which is attributed to the limited air convection resulting in the insufficient oxygen supply in the feed once it is extracted.