Integration of air separation and partial oxidation of methane in the La0.4Ba0.6Fe0.8Zn0.2O3−δ membrane reactor

A disc-membrane made of the La0.4Ba0.6Fe1−xZnxO3−δ (LBFZ-x) perovskite oxide with x = 0.2 was used to carry out air separation. The oxygen permeation through the membrane was driven by either He sweeping or partial oxidation of methane (POM) at the permeate side of membrane. Both operation temperature and thickness of the LBFZ-0.2 membrane impact oxygen permeation flux under a permeation gradient. Oxygen permeation flux increases with the decrease in the thickness of membrane and the trend gradually levels off. A much greater oxygen flux through the LBFZ-0.2 membrane was achieved when the POM reaction instead of the He sweeping was used to drive oxygen permeation. It could reach 12 cm3 cm−2 min−1 through a 0.5 mm-thick LBFZ-0.2 membrane. The most influential property exhibited by the LBFZ-0.2 membrane lies in its chemical stability under the reducing atmosphere of POM. The membrane remains intact and supplies oxygen to maintain almost quantitative CH4 conversion and CO selectivity through a 500 h testing period at 900 °C. The chemical stability of LBFZ-0.2 was also verified by the retention of perovskite structure.

► Exploring perovskite La0.4Ba0.6Fe0.8Zn0.2O3−δ oxygen permeation membrane. ► Impact of the permeation gradient across membrane on oxygen flux. ► Driven by dry reforming of methane an oxygen flux of 12 cm3 cm−2 min−1 is obtained. ► Achieving a high CH4 conversion (∼100%) and a high CO selectivity (95–99%). ► Manifesting long-term stability of membrane under the dry reforming conditions.