Manganese oxide dissociation kinetics for the Mn sub(2)O sub(3) thermochemical water-splitting cycle. Part 1: Experimental

It is shown that the dissociation of Mn sub(2)O sub(3) to MnO in a short residence time aerosol flow reactor can achieve high conversions approaching 75% when the concentration of oxygen is kept below 0.25%. Significant recombination reaction occurs when the oxygen content exceeds [not, vert, similar]0.25% by volume. A dual reaction mechanism for Mn sub(2)O sub(3) dissociation was found: R sub()AvramiErofeev-A sub(1)e super(-)Eda,1 RTin1-X)[-ln(1-X)] super(()n1)/nR sub()Orderof_reaction-A sub(2)e super(-)E da,2RT1-X) super()nwith the transition from one mechanism to the other occurring at an extent of reaction of approximately 0.6. Rate constants for the two mechanisms were calculated to be 1.8x10 super(7)+/-1.3x10 super(7) and 5.6x10 super(3)+/-4.1x10 super(3) s super(-1), respectively, for oxygen concentration