The oxidative stream reforming of methane to syngas in a thin tubular mixed-conducting membrane reactor

The oxidative stream reforming of methane (OSRM) to syngas, involving coupling of exothermic partial oxidation of methane (POM) and endothermic steam reforming of methane (SRM) processes, was studied in a thin tubular Al2O3-doped SrCo0.8Fe0.2O3−δ membrane reactor packed with a Ni/γ-Al2O3 catalyst. The influences of the temperature and feed concentration on the membrane reaction performances were investigated in detail. The methane and steam conversions increased with increasing the temperature and high conversions were obtained in 850–900 °C. Different from the POM reaction, in the OSRM reaction the temperature and H2O/CH4 profoundly influenced the CO selectivity, H2/CO and heat of the reaction. The CO selectivity increased with increasing the temperature or decreasing the H2O/CH4 ratio in the feed owing to the water gas shift reaction (H2O + CO → CO2 + H2). And the H2 selectivity based on methane conversion was always 100% because the net steam conversion was greater than zero. The H2/CO in product could be tuned from 1.9 to 2.8 by adjusting the reaction temperature or H2O/CH4. Depending on the temperature or H2O/CH4, furthermore, the OSRM process could be performed auto-thermally with idealized reaction condition.