Oxidative Coupling of Methane in a Perovskite Hollow-Fiber Membrane Reactor

A La0.6Sr0.4Co0.2Fe0.8O3-(alpha) (LSCF) perovskite hollow-fiber membrane with an asymmetric structure has been prepared via a combined phase inversion/sintering technique where poly(ether sulfone) is employed as a polymeric binder, N-methyl-2-pyrrolidone as a solvent, and poly(vinylpyrrolidone) as an additive, respectively. The prepared LSCF hollow-fiber membranes are gastight and have been further fabricated into a hollow-fiber membrane reactor (HFMR) for oxidative coupling of methane (OCM). The experimental results indicate that the newly developed LSCF hollow-fiber membrane exhibits good oxygen permeation rate, methane conversion, and C2 yield compared to conventional disk-shaped membranes. A C2 yield of 15.3% with a corresponding selectivity of 43.8% has been achieved in the HFMR at 950 C with feed flow rates of a CH4-Ar mixture and air of 17.2 and 32.9 cm^3(STP)/min, respectively. The results further indicate that the operating temperature for OCM in the HFMR should not be higher than 950 C. However, higher operating temperature is favorable to the formation of ethylene. After 4 weeks of OCM experiments, the LSCF membranes remain intact in its perovskite structure, mechanical strength, and OCM performances.