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

摘要

The partial oxidation of methane to synthesis gas (syngas) was performed on a tubular La_0.66Sr_0.4Co_0.2Fe_0.8O3-δ membrane reactor packed with a Ni/γ-Al_2O_3 catalyst. In l098ul l58 K, the CH_4 conversion was larger than 96/100 with the CO selectivity larger than 97/100 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 H_2/CO ratio in the product larger than 2) occurred at high CH_4 concentration (>6/100) 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 3-7 h.