The work presented in this paper is part of a larger study aimed at examining the redox (i.e. reduction / oxidation) behaviour of mixed metallic oxide oxygen carriers for chemical looping combustion; one of several emerging technologies for in-situ capture of CO2. The paper specifically summarises the results of a series of reactivity studies on mixtures of Cu, Fe and Ni oxides under reducing environments of H2, CO and CH4. Experiments were conducted in a TGA over a range of temperatures between 500 and 950oC at atmospheric pressure. In each set of experiments the concentration of the reacting gas was systematically varied from 20-70% volume fraction. Similarly, metal oxides of interest were physically mixed at three blending ratios of 25%, 50% and 75%. Over 600 experiments were carried out to determine the kinetic behaviour of physically mixed oxygen carriers under conditions pertinent to chemical looping combustion. All mixed carrier particles exhibited high reactivity during the reduction. The kinetic properties were extracted from experimental measurements of the weight loss using a modified shrinking core model. It was found that the conversion time of mixtures were the geometric means of the conversion times of the parent materials.
Chemeca 2010: Engineering at the Edge. Proceedings of Chemeca 2010: Engineering at the Edge (Adelaide, S.A. 26-29 September, 2010)