Modified operating mode for improving the lifetime of mixed-conducting ceramic membrane reactors in the POM environment

Tubular perovskite-related yttria-stabilized zirconia (YSZ) promoted SrCo0.4Fe0.6O3-delta oxygen-permeable membrane reactors, packed with NiO/Al2O3 catalyst, were investigated for the partial oxidation of methane (POM) to syngas. When helium-diluted methane was introduced into the tube side of the membrane reactors, the membrane tubes could survive only for 4-6 h. X-ray diffraction (XRD) analyses showed that, at the inlet position of the membrane tubes, serious phase decomposition occurred, which resulted in the breakage of the membrane tubes. A modified feed mode was suggested to prolong the lifetime of the membrane tubes in the POM environment by adding a small amount of oxygen in dilute methane and introducing the mixed gas through the tube side. Under the modified operating mode, the membrane reactors were successfully operated for over 70 h.