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 La0.6Sr0.4Co0.2Fe0.8O3-delta membrane reactor packed with a Ni/g amma-Al2O3 catalyst. In 1098-1158 K, the CH4 conversion was larger than 96% with the CO selectivity larger than 97% at low methane concentrations in t he feed. CH4 conversion decreased and CO selectivity remained essentially c onstant with increasing concentration of methane in the feed. Carbon deposi tion on the surface of the catalyst (with H-2/CO ratio in the product large r 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/sublimati on and segregation of elements on the membrane surfaces, which led to a red istribution of the metal ions across the membrane after being operated in t he membrane reactor at the reaction temperature for 3-7 h. (C)2000 Elsevier Science B.V. All rights reserved.