Screening of Combined Mn-Fe-Si Oxygen Carriers for Chemical Looping with Oxygen Uncoupling (CLOU)

Abstract

Combined oxygen carriers of Mn, Fe, and Si were screened for the chemical looping with oxygen uncoupling process with the objective of identifying materials with high reactivity and sufficient attrition resistance. Eleven oxygen carrier materials were produced by spray-drying and then calcined for 4 h at 1100 and 1200 °C. The ability of the oxygen carriers to release oxygen and to convert gaseous fuels was investigated in a batch fluidized-bed reactor under alternating reducing and oxidizing conditions for temperatures ranging from 850 °C to 1050 °C. The attrition behavior of the different materials was evaluated in a jet-cup attrition rig. All investigated oxygen carriers proved to release oxygen and showed high reactivity toward synthesis gas (50% CO in H2). Oxygen carrier materials with comparably lower mechanical stability were found to have a higher reactivity toward methane. One of the investigated formulations showed to have both high mechanical stability and resistance toward attrition, as well as good methane conversion and oxygen release.