Oxygen-Carrier Development of Calcium Manganite-Based Materials with Perovskite Structure for Chemical-Looping Combustion of Methane

The present work is related to the upscaling of calcium manganite-based oxygen-carrier materials, which have a perovskite structure, both with respect to the use of inexpensive raw materials, i.e., instead of pure chemicals, and the upscaling of production to multitonne batches. Results are presented from the two different stages of material development, i.e., raw material selection and upscaling. The evaluation involves both operation in chemical-looping combustor units of 300 W and 10 kW, and material characterization. In the latter unit, the gas velocities in the riser and in the grid-jet zone of the gas distributor come close to gas velocities of industrial-scale units and, therefore, this unit is also used to assess particle lifetime. Results from the various chemical-looping combustion units and oxygen-carrier materials produced from various raw materials of both high and low purity show that very high degrees of fuel conversion can be reached while achieving very high oxygen-carrier lifetimes. The composition of the oxygen-carrier materials seems robust and flexible with respect to the precursors used in its manufacturing.