Syngas production with CO₂ utilization through the oxidative reforming of methane in a new cermet-carbonate packed-bed membrane reactor

A series of γ-LiAlO₂-Ag cermets was studied to be integrated into a packed-bed membrane reactor with potential application in the selective separation of CO₂ and O₂; and simultaneous syngas production through the coupling of the oxidative CO₂ reforming of methane process. The γ-LiAlO₂ was chemically synthesized and incorporated into an Ag matrix, in different amounts, by powder metallurgy using ball milling and uniaxial pressing techniques. The obtained cermets exhibit excellent wettability properties against molten carbonates, facilitating their infiltration and forming dense dual-phase membranes with the molten salts. Moreover, the cermet supports show corrosion resistance against the alkaline molten carbonates and superior thermal stability due to the γ-LiAlO₂ suppresses the sintering of the metallic phase. The membrane's performance was evaluated in the selective gas separation at high temperatures. The membranes exhibit simultaneous CO₂ and O₂ permeation with a flux of 0.78 and 0.43 ml·min^-1·cm^-2, at 850 °C, respectively. Besides, during the oxidative reforming process, the membrane reactor shows conversion of about 100 % of CO₂ under the studied separation and reaction conditions. The syngas (H₂+CO) production reaches values of 4.94 ml·min^-1·cm^-2 at 825 °C using a 10 % Ni/CeO₂ catalyst. A long-term permeation test was conducted for 225 h, during which the membrane exhibits excellent thermal and chemical stability properties under continuous reaction conditions of syngas production. This fact is attributed to its outstanding chemical inertness against carbonates as well as the observed sinterability properties of the used cermet support.