Extremely Stable and Durable Mixed Fe-Mn Oxides Supported on ZrO2 for Practical Utilization in CLOU and CLC Processes

This paper contains the results of research on a promising combustion technology known as chemical looping combustion (CLC) and chemical looping with oxygen uncoupling (CLOU). The remarkable advantages of CLC are, among others, that concentrated CO2 stream can be obtained after water condensation without any energy penalty for its separation or significant decrease of NOx emissions. The objective of this work was to prepare a novel bi-metallic Fe-Mn supported on ZrO2 oxygen carriers. Performance of these carriers for the CLOU and CLC process with nitrogen/air and hard coal/air was evaluated. One-cycle CLC tests were conducted with supported Fe-Mn oxygen carriers in thermogravimetric analyzer utilizing hard coal as a fuel. The effects of the oxygen carrier chemical composition and process temperature on the reaction rates were determined. Our study proved that for CLOU, properties formation of bixbyite and spinel forms are responsible. Among iron ferrites, we concluded that iron-rich compounds such as Fe2MnO4 over FeMn2O4 spinel type oxides are more effective for CLOU applications.