A fluidized bed model of the fuel reactor for a Chemical Looping with Oxygen Uncoupling process

Coal-fired power plants contribute significantly to the global electricity production. The reduction of energy penalty associated with the capture of carbon dioxide emitted from coal-fired power plants is one of the significant challenges in the economic development of carbon capture, utilization and sequestration(CCUS) technologies. Chemical Looping with Oxygen Uncoupling (CLOU) of solid fuels is one of the many processes which are currently being investigated as a promising process to reduce energy penalty associated with CO₂ capture. In CLOU, oxygen is released by dissociation of the oxygen carrier (usually a metal oxide) and is consumed by the solid fuel. The CLOU process is comprised of two reactors: an air reactor, where the oxygen carrier is oxidized; and a fuel reactor where the oxygen carrier dissociates into oxygen and a metal oxide of a lower oxidation state. The oxygen released then reacts with the solid fuel in the fuel reactor. In chemical-looping combustion (CLC) the solid fuel has to be gasified initially to syngas. The syngas subsequently reacts with the circulating oxygen carrier. As the gasification step is avoided in CLOU, the rate of reaction is significantly faster leading to potentially smaller fuel reactor volumes. In this study, the fuel reactor in a CLOU process has been modeled by a bubbling fluidized bed model employing the rate analysis of reported batch fluidized bed CLOU experimental data. Oxygen and carbon dioxide concentration trends predicted from the model are compared with literature results in this paper.