Effective direct chemical looping coal combustion using bimetallic Ti-supported Fe2O3-MnO2 oxygen carriers

In this paper five bimetallic Fe₂O₃-MnO₂ oxygen carriers supported on TiO₂ were evaluated for direct hard coal combustion via chemical looping path. The oxygen carriers were obtained via mechanical mixing and high-temperature calcination. The samples contained varying amounts of Fe₂O₃ (20–50 wt.%) and MnO₂ (65–30 wt.%) but an identical amount of inert material (15 wt.%). Both the impact of the oxygen carrier's composition and the process temperature on their reactivity with the selected hard coal were evaluated. The amount of manganese in the oxygen carriers correlated positively with their reactivity toward the fuel. It was concluded that after eight reaction cycles the oxygen carriers remained resilient for side reactions with the ash residue. Thus, the physicochemical stability of the presented oxygen carriers was proved. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.