Pelletizing and Performance of Non-calcined Fe-based Oxygen Carriers Using Circulating Fluidized Bed Fly Ash as an Inert Support

A series of non-calcined Fe₂O₃/circulating fluidized bed (CFB) fly ash oxygen carrier particles were prepared by CFB fly ash as the inert support and Fe₂O₃ as the active component via the extrusion-spheronization method, and their mechanical and reactive properties were tested. It was found that the activation effect of Ca(OH)₂ on CFB fly ash is superior to that of NaOH. When the mass fraction of Ca(OH)₂ is 5%, the optimal activation effect can be achieved, with the compressive strength of the oxygen carrier particles reaching 16.92 MPa. The crushing load distribution is approximately found to follow a normal pattern, with an average crushing load of 53.1 N. When the mass ratio of Fe₂O₃ to Ca(OH)₂-activated CFB fly ash is set at 1.5∶1, the compressive strength of the oxygen carrier particles could reach 17.38 MPa, and the wear rate is only 0.92%, indicating the best mechanical properties. Moreover, good reactivity and the best comprehensive performance are also observed. The performance of oxygen carrier particles with CFB fly ash as the inert support is found to be similar to that with Al₂O₃ as the inert support, verifying the feasibility of using CFB fly ash as an inert support.