Mechanism of Methane Chemical Looping Combustion with Hematite Promoted with CeO2

Abstract

Chemical looping combustion (CLC) is a promising technology for fossil fuel combustion that produces sequestration-ready CO2 stream, reducing the energy penalty of CO2 separation from flue gases. An effective oxygen carrier for CLC will readily react with the fuel gas and will be reoxidized upon contact with oxygen. This study investigated the development of a CeO2-promoted Fe2O3–hematite oxygen carrier suitable for the methane CLC process. Composition of CeO2 is between 5 and 25 wt % and is lower than what is generally used for supports in Fe2O3 carrier preparations. The incorporation of CeO2 to the natural ore hematite strongly modifies the reduction behavior in comparison to that of CeO2 and hematite alone. Temperature-programmed reaction studies revealed that the addition of even 5 wt % CeO2 enhances the reaction capacity of the Fe2O3 oxygen carrier by promoting the decomposition and partial oxidation of methane. Fixed-bed reactor data showed that the 5 wt % cerium oxides with 95 wt % iron oxide produ...