Preparation and Characterization of a Perovskite-type Mixed Conducting SrFe0.6Cu0.3Ti0.1O3−δ Membrane for Partial Oxidation of Methane to Syngas*

Dense membrane with the composition of SrFe0.6Cu0.3Ti0.1O3−δ (SFCTO) was prepared by solid state reaction method. Oxygen permeation flux through this membrane was investigated at operating temperature ranging from 750°C to 950°C and different oxygen partial pressure. XRD measurements indicated that the compound was able to form single-phased perovskite structure in which part of Fe was replaced by Cu and Ti. The oxygen desorption and the reducibility of SFCTO powder were characterized by thermogravimetric analysis and temperature programmed reduction analysis, respectively. It was found that SFCTO had good structure stability under low oxygen pressure at high temperature. The addition of Ti increased the reduction temperature of Cu and Fe. Performance tests showed that the oxygen permeation flux through a 1.5 mm thick SFCTO membrane was 0.35–0.96 ml·min−1·cm−2 under air/helium oxygen partial pressure gradient with activation energy of 53.2 kJ·mol−1. The methane conversion of 85%, CO selectivity of 90% and comparatively higher oxygen permeation flux of 5 ml·min−1·cm−2 were achieved at 850°C, when a SFCTO membrane reactor loaded with Ni-Ce/Al2O3 catalyst was applied for the partial oxidation of methane to syngas.