Evaluation of a bauxite cement-bonded Fe-based oxygen carrier during a hundred of cycles under coal-fueled chemical looping combustion conditions

The development of cost effective oxygen carriers (OCs) is one of the key factors for chemical looping combustion (CLC) to become a viable technology for controlling CO2 emissions from fossil fueled power plants, especially those using coal. Although bauxite cement-bonded Fe-based OCs have been identified as a potential candidate for CLC implementation, few studies have examined their long-term stability and process effectiveness under conditions of coal fueled power. Hence, this study examined long-term effectiveness of a bauxite cement-bonded Fe-based OC for conversion of coal and production of CO2-enriched off-gases under cycled processing typical to CLC technology. During reduction and oxidation cycles, the exhaust gas and samples of the OC were extracted from a laboratory scale, coal burning fluidized bed reactor to enable their characterization and provide insight into the process performance and physical attributes of the OC conducive to its application. The results show that the bauxite cement-bonded OC maintained high reactivity and regeneration capacity, and the mechanical strength integrity to withstand the mechanical and chemical stresses associated with fluidized bed and solids transfer typical to CLC.