391c High Temperature Rapid Dissociation of Mn2O3 In An Aerosol Flow Reactor

391c High Temperature Rapid Dissociation of Mn₂O₃ In An Aerosol Flow Reactor

Todd M. Francis, Christopher Perkins, Paul Lichty, and Alan W. Weimer. Department of Chemical and Biological Engineering, University of Colorado, 1111 Engineering Drive, Boulder, CO 80309-0424

A three-step metal oxide cycle to produce renewable hydrogen has been proposed. This cycle employs manganese oxide and solar energy to produce hydrogen:

½Mn₂O₃ → MnO + ¼O₂ (1)

MnO + NaOH → ½H₂ + NaMnO₂ (2)

NaMnO₂ + ½H₂O → ½Mn₂O₃ + NaOH (3)

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H₂O → H₂ + ½O₂ (4)

Most work on the manganese oxide cycle has focused on the hydrogen generating step (Equation 2) and the product recovery step (Equation 3) with little work done on the reduction step (Equation 1). It is essential to understand the reduction step because the entire feasibility of the manganese oxide cycle is based on this reaction having a high overall conversion. Specifically, the viability of the MnO and O₂ phase separation must be investigated to determine how much recombination might occur during the quench step. In this study, experimental designs were done to investigate the affect of oxygen on the conversion of Mn₂O₃ to MnO. Along with the results from this study, results from a CFD simulation of Mn₂O₃ through an aerosol flow reactor will be presented.