A novel porous-dense dual-layer composite membrane reactor with long-term stability

A porous-dense dual-layer composite membrane reactor was proposed. The dual-layer composite membrane composed of dense 0.5 wt % Nb₂O₅-doped SrCo_0.8Fe_0.2O_3-δ (SCFNb) layer and porous Ba_0.3Sr_0.7Fe_0.9Mo_0.1O_3-δ (BSFM) layer was prepared. The stability of SCFNb membrane reactor was improved significantly by the porous-dense dual-layer design philosophy. The porous BSFM surface-coating layer can effectively reduce the corrosion of the reducing atmosphere to the membrane, whereas the dense SCFNb layer permeated oxygen effectively. Compared with single-layer dense SCFNb membrane reactor, no degradation of performance was observed in the dual-layer membrane reactor under partial oxidation of methane during continuously operating for 1500 h at 850°C. At 900°C, oxygen flux of 18.6 mL (STP: Standard Temperature and Pressure) cm^-2 min^-1, hydrogen production of 53.67 mL (STP) cm^-2 min^-1, CH₄ conversion of 99.34% and CO selectivity of about 94% were achieved.