Tubular lanthanum cobaltite perovskite-type membrane reactors for partial oxidation of methane to syngas

The partial oxidation of methane to synthesis gas (syngas) was performed on a tubular La_0.6Sr_0.4Co_0.2Fe_0.8O(3-δ) membrane reactor packed with a Ni/γ-Al₂O₃ catalyst. In 1098-1158K, the CH₄ conversion was larger than 96% with the CO selectivity larger than 97% at low methane concentrations in the feed. CH₄ conversion decreased and CO selectivity remained essentially constant with increasing concentration of methane in the feed. Carbon deposition on the surface of the catalyst (with H₂/CO ratio in the product larger than 2) occurred at high CH₄ concentration (>6%) in the feed. Analysis of SEM, XRD and EDS on the used membrane showed metal ion reduction/sublimation and segregation of elements on the membrane surfaces, which led to a redistribution of the metal ions across the membrane after being operated in the membrane reactor at the reaction temperature for 3-7h. Copyright (C) 2000 Elsevier Science B.V.