Combined steam and carbon dioxide reforming of methane over porous nickel based catalysts

Abstract

The phase composition and texture of nickel catalysts supported on a porous nickel ribbon with a MgO underlayer were studied. In the supported reduced catalysts (900 °C, H₂), nickel crystallites were epitaxially bound to MgO. The reaction of combined steam and carbon dioxide reforming of methane to synthesis gas (750 °C, CH₄/CO₂/H₂O/N₂ = 35/23/39/3, GHSV = 62.5 L g⁻¹ h⁻¹) was performed in a flow reactor in the presence of the developed catalysts. The catalysts with the MgO underlayer completely covering the nickel ribbon showed stable activity throughout the test period (18 h); after the reaction, no carbon deposits were found in them. The resistance of these catalysts to carbonization was attributed to both the formation of nickel crystallites epitaxially bound to MgO and the formation of the MgO underlayer that covers the nickel ribbon and prevents its contact with the reaction medium. Based on the supported nickel catalysts, a monolithic catalyst was prepared and tested in the developed flow reactor. According to the test data, methane conversion over the monolithic catalyst at a contact time of 0.29 s was not lower than 94% and the synthesis gas yield was 90%; at this contact time, experimental values were close to the calculated equilibrium values.