文摘
The objective of this study was to establish the reaction kinetics involved in redox cycles of the CaMn0.9Mg0.1O3鈭捨?/sub> material to be used as an oxygen carrier in the chemical-looping-combustion process. The oxygen-transport capacity and reactivity of this material during consecutive reduction and oxidation steps with gaseous compounds (CH4, H2, CO, and O2) were studied in a thermogravimetric analysis apparatus. The oxygen uncoupling properties of this material were also analyzed. It was found that material reactivity increased with the number of redox cycles, whereas the oxygen-transport capacity decreased with the cycle number until it was stabilized or 鈥渁ctivated鈥? Conversion versus time curves at different temperatures (973鈥?273 K) and reacting gas concentrations (5鈥?0 vol %) were used for kinetic determination. The grain model with control by chemical reaction and diffusion through the product layer was used to obtain the kinetic parameters for fresh and 鈥渁ctivated鈥?particles.