Chemical looping combustion with oxygen uncoupling (CLOU) of a coal char in fluidized bed reactor

Application of chemical looping combustion (CLC) to solid fuels would be mostly effective in contrasting GHG emissions. The present paper addresses chemical looping combustion with oxygen uncoupling (CLOU) as a mean to overcome the inherent limitations of the solid-solid reaction between the fuel and the oxygen carrier in CLC. The validity of this concept has been tested by means of experiments with a bituminous coal char in a bench scale fluidized bed reactor in oxygen-free atmosphere, using commercial reagent-grade CuO-dispersed alumina particles as oxygen carrier. Combustion was monitored by continuous analysis of gases at the exhaust. Regeneration of the carrier was carried out in the same reactor at constant temperature in air. The reactivity of the carrier has been determined after multiple oxidation/reduction cycles to assess the occurrence of deactivation. A complementary activity was carried out in a thermogravimetricapparatus in order to assess the inherent extent and rate of oxygen uptake of the carrier over repeated oxidation/reduction cycles, and compared with those of pure copper oxide. Based on the experimental results the possibility of application of the carrier in chemical looping processes is discussed.