Hydrogen production via solar-aided water splitting thermochemical cycles with nickel ferrite: Experiments and modeling

Authors

  • Christos Agrafiotis,

    Corresponding author
    • Aerosol and Particle Technology Laboratory (APTL), Chemical Process Engineering Research Institute, Center for Research and Technology-Hellas (CERTH/CPERI), Thermi - Thessaloniki, Greece
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  • Alexandra Zygogianni,

    1. Aerosol and Particle Technology Laboratory (APTL), Chemical Process Engineering Research Institute, Center for Research and Technology-Hellas (CERTH/CPERI), Thermi - Thessaloniki, Greece
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  • Chrysoula Pagkoura,

    1. Aerosol and Particle Technology Laboratory (APTL), Chemical Process Engineering Research Institute, Center for Research and Technology-Hellas (CERTH/CPERI), Thermi - Thessaloniki, Greece
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  • Margaritis Kostoglou,

    1. Dept. of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
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  • Athanasios G. Konstandopoulos

    Corresponding author
    1. Dept. of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece
    • Aerosol and Particle Technology Laboratory (APTL), Chemical Process Engineering Research Institute, Center for Research and Technology-Hellas (CERTH/CPERI), Thermi - Thessaloniki, Greece
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Correspondence concerning this article should be addressed to C. Agrafiotis, Deutsches Zentrum für Luft- und Raumfahrt (DLR), German Aerospace Center, Institute of Solar Research, Solar Chemical Engineering, Linder Höhe, 51147 Koeln, Germany at Christos.Agrafiotis@dir.de and A. G. Konstandopoulos at agk@cperi.certh.gr.

Abstract

Water splitting — thermal reduction cyclic studies with NiFe2O4 redox materials were performed in a differential fixed-bed laboratory reactor in the temperature range 700–1,400°C to quantify the effects of operation temperatures and steam mole fraction on hydrogen and oxygen yields. Hydrogen yield increased drastically by an increase of the water splitting temperature from 800 to 1,000°C reaching a plateau at 1,100°C. In parallel, a simple mathematical model was formulated describing the water splitting process via the heterogeneous surface reactions of water vapor with the redox powder material, from which, in conjunction to the aforementioned experiments, the kinetic parameters of the water splitting and thermal reduction reactions were extracted. The water splitting kinetic constants exhibited weak temperature dependence between 700 and 1,100°C suggesting the existence on the redox material of more than one type of oxygen storage sites with respect to ease of exposure and accessibility to the gas phase. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1213–1225, 2013

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