Influence of nitric oxide on the oxygen permeation behavior of La0.6Sr0.4Co0.2Fe0.8O3−δ perovskite membranes

Abstract

• NO influence on oxygen permeation of perovskite membrane is probed. • The presence of NO would decrease the oxygen permeability below 900 °C. • The presence of NO can change the membrane surface. • NO influence can be avoided by lifting the operation temperature above 900 °C. Mixed conducting perovskite membrane has been intensively investigated as a possible new technology for oxygen production to replace the conventional cryogenic distillation which is capital and energy intensive. The perovskite membrane has the potential to be applied in the clean energy projects like oxy-fuel coal combustion if the membrane can withstand the real application conditions. Nitric oxide (NO) is an inevitable ingredient of flue gas from power plants, and it is important to understand the possible influence from NO on the perovskite membranes for producing pure oxygen for oxy-fuel project where the flue gas would be used as the sweep gas for the membrane operation. The influence of NO on the oxygen permeation properties of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ (LSCF) perovskite membrane is investigated by a variety of characterization techniques. The results indicate that the oxygen permeability of the LSCF membrane decreases significantly at the temperature below 900 °C. XRD, SEM and SEM-EDX characterizations indicate the generation of another porous phase damaging the membrane and accounting for the oxygen flux decrease. However, the negative effect from NO on the oxygen permeation would disappear when the temperature is elevated above 900 °C, on which NO would be decomposed to nitrogen and oxygen and no longer negatively influences the membrane.