Production and properties of substituted LaFeO3-perovskite tubular membranes for partial oxidation of methane to syngas

Tubular membranes of La0.6Ca0.4Fe0.75Co0.25O3−δ and La0.5Sr0.5Fe1−yTiyO3−δ (y = 0, 0.2) for the application of partial oxidation of methane to syngas were produced by thermoplastic extrusion and investigated by oxygen permeation measurements. The optimum ceramic content in the feedstock for extrusion was found to be 51 vol% as a result of rheology measurements. Tubes with an outer diameter of 4.8–5.5 mm and thickness of 0.25–0.47 mm were produced with densities higher than 95% of the theoretical density. The oxygen permeation flux of the tubular membranes was measured with air on one side and Ar or Ar + CH4 mixture on the other side. The oxygen permeation rate decreased with Ti-substitution while it was considerably increased by introduction of 5% methane into the system. The normalized oxygen fluxes in air/Ar gradient at 900 °C were measured to be 0.06, 0.051, and 0.012 μmol cm−2 s−1 for LCFC, LSF, and LSFT2, respectively, and 0.18 μmol cm−2 s−1 for LSFT2 with 5% methane.