Oxygne Transport Kinetics in La_0.5Sr_0.5Fe_0.8Ga_0.2O_(3-#delta#) Membranes Under Both Small and Large Oxygen partial Pressure Gradients

摘要

Oxygen permeation through a new perovskite la_0.5Sr_0.5Fe_0.8Ga_0.2O_(3-#delta#) membrane has been measured both under small and large oxygne partial pressure gradients. IN both cases oxygen transport is close to surface limited. By modeling the pressure depnedence of the oxygen flow rate under small pessure gradient an ambipolr diffuson coefficient 9.65*10~(-7) cm~2/s and a surface exchange coefficient 7.15*10~(-6)cm/s at 974 deg C ere determined. With air/CO, CO_2 on the permeate side, the permeability increases linearly with the partial pressure of CO. The obsrved increase is greater than the maximum enhancement predicted by our model.