A comparative study of Ba0.5Sr0.5Co0.8Fe0.2Ox (BSCF) and SrFeCo0.5Ox (SFC) ceramic membranes used for syngas production

Abstract

Dense oxygen permeable ceramic membranes are promising materials for separating oxygen from air and for syngas production. In this work, the role of two different membrane materials, Ba0.5Sr0.5Co0.8Fe0.2Ox (BSCF) and SrFeCo0.5Ox (SFC), in the conversion of methane, has been studied. Pulse and temperature programmed desorption studies of CO and CO2 showed a higher CO and CO2 adsorption on BSCF compared to the SFC membrane. More CO adsorption resulted in more CO2 production. Raman spectroscopy of BSCF and SFC ceramic materials after CO and CO2 exposure showed carbonate species on these samples. Both H2 and O2 adsorption were significantly higher on BSCF, with significant water formation in the presence of hydrogen. Reaction investigations over Pt-based catalysts demonstrated higher methane conversion and a higher H2:CO ratio on the BSCF membrane than on the lower flux SFC membrane because of more interaction of the products with BSCF. Under reaction conditions, the simultaneous occurrence of steam and CO2 reforming of methane would lead to a higher methane conversion and a higher H2:CO ratio on BSCF. The onset temperature of oxygen release for BSCF was observed to be lower than that for SFC while the amount of oxygen release was significantly greater. These studies suggest that BSCF might be suitable for hydrocarbon conversion reactions at much lower temperatures than conventional dense ceramic membranes.