Experimental study of oxygen transport membranes for oxy-fuel combustion reactors

Abstract

There is a growing pressure on industry to reduce carbon dioxide emissions from combustion processes while meeting the growing energy demand, resulting in an increase in the development of carbon capture technology. Current practices available, such as chemical looping combustion (CLC) or cryogenic air separation units, separate oxygen from the atmosphere and feed it into combustor to eliminate any nitrogen in the reactor and produce a rich CO₂ exhaust that can be captured and contained for future use. However, by implementing these technologies there is a significant energy penalty. One potential alternative is an oxygen transport membrane reactor that has the potential to provide a large amount of high purity oxygen at minimal energy costs. This work investigates the performance of perovskite-type La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) and SrSc_0.1Co_0.9O_3-δ (SSC) membrane reactors for the combustion of methane in various configurations. The ceramic membranes exploited here are oxygen semi-permeable, dense ceramic membranes with mixed oxygen ionic and electronic conductivity at high temperatures. Planar and tubular reactors were fabricated and studied with a methane fuel. The oxygen permeability feasibility of the membrane reactors were studied and confirmed. The CO₂ selectivity at various test conditions were also reported with the maximum selectivity achieved 87.0 % selectivity.