Coupling of N2O decomposition with CO2 reforming of CH4 in novel cobalt-free BaFe0.9Zr0.05Al0.05O3−δ oxygen transport membrane reactor

Abstract

Coupling of N2O decomposition with CO2 reforming of CH4 was demonstrated in cobalt-free perovskite BaFe0.9Zr0.05Al0.05O3−δ (BFZ-Al) membrane reactor. Perovskite oxide BFZ-Al was synthesized by EDTA–citric acid complexing method. The stability of BFZ-Al and BaFexZryCo1−x−yO3−δ (BFZ-Co) was studied under hydrogen atmosphere. X-ray diffraction analysis indicates that BFZ-Al shows a better stability compared to cobalt-based perovskite BFZ-Co. The oxygen permeation rate of BFZ-Al dense membrane was investigated from 810 to 960°C, and the oxygen permeation rate reached 0.85mlmin−1cm−2 at 960°C. N2O decomposition in BFZ-Al membrane reactor was studied under three different sweep gas atmospheres including He, He/CH4, and He/CH4/CO2. Comparatively, a higher N2O conversion was achieved by using the sweep gas mixture He/CH4/CO2 than only using He or He/CH4. Therefore, the simultaneous N2O decomposition and syngas production via dry reforming was studied in BFZ-Al membrane reactor by using N2O and He/CH4/CO2 as feed gas and sweep gas, respectively. At 900°C, almost complete N2O conversion was achieved owing to the efficient in situ removal of the inhibitor oxygen through BFZ-Al membrane. CH4 conversion was found to be around 97% with 94% CO selectivity at 900°C, and no obvious decline in the activity and selectivity was observed even after 100h of the operation.