One stone two birds: Simultaneous realization of partial oxidation of methane to syngas and N2 purification via robust ceramic oxygen-permeable membrane reactors

Abstract

To obtain liquid fuel and high purity N2, extensive energy is consumed in converting methane to syngas (H2 + CO) and in separating N2 from air. Conventional studies were mainly focused on the partial oxidation of methane (POM) to syngas instead of the N2 purification. Here, we report a win-win scheme of POM to syngas and N2 purification using a high performance ceramic hollow membrane reactor. The mixed ionic and electronic conducting doped La0.8Ca0.2Fe0.95Ag0.05O3−δ (LCF-Ag) powder enduring harsh environment at high temperatures was synthesized and prepared into hollow fibre membranes. By using a self-designed injection device, the high-efficiency catalyst (Ni/LaNiO3/γ-Al2O3) was uniformly anchored on the inner surface of the hollow fiber along the whole length to guarantee the ideal reaction rate to achieve the desirable reaction efficiency, product selectivity and nitrogen purity. At 900 ℃, 99% methane conversion, 93% CO selectivity and syngas with suitable ratio of H2/CO were obtained by using both membrane modules containing one single or three hollow fiber membranes. Meanwhile, N2 with purity over 99.9% can be separated from gas mixture (synthetic air) due to the removal of oxygen which was consumed by POM. These results suggest that POM to syngas and N2 purification can be achieved using a high-performance ceramic hollow fiber membrane reactor toward green and energy-saving technology. This is a promising win-win scheme of catalytic reaction combining with gas separation.