Reduction kinetics of a fluidizable nickel-alumina oxygen carrier for chemical-looping combustion

This study investigates the kinetic modelling of oxygen carrier reduction by methane in the combustion reactor of the chemical-looping combustion process. The species being reduced and the stability of the fluidizable oxygen carrier sample over repeated reduction-oxidation cycles are established using the temperature programmed reduction and oxidation and the pulse chemisorption characterization methods. The power-law relation, the nucleation and nuclei growth model and the shrinking-core models are considered to interpret the experimental kinetics of the oxygen carrier reduction. The obtained results show that the nucleation and nuclei growth model best describes the experimental data providing parameters with adequate statistical fitting indicators.