Browsing by Author "De Smith, Robert Michael"

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    Improving the efficiency of a ceria reduction-oxidation cycle through the choice of operating conditions and ceria morphology
    (2014-05) De Smith, Robert Michael
    Pathways for improving the efficiency of ceria-based thermochemical cycling for solar-driven fuel production are investigated. First, the operating conditions of an isothermal CO2 splitting cycle are optimized to improve process efficiency. The optimum conditions are a sweep gas flow rate of 150 mL min-1 g-1, a CO2 flow rate of 50 mL min-1 g-1, a reduction time of 100 s, and an oxidation time of 155 s. A quasi-equilibrium model is developed to predict the rates of ceria reduction and oxidation. Finally, a new ceria morphology, wood templated ceria, is used to improve the heterogeneous oxidation reaction rates by maintaining a high surface area when exposed to the extreme temperatures required for ceria reduction. Wood templated ceria performs well at reduction temperatures up to 1400 °C, reaching peak CO production rates of 9 mL min-1 g-1, but rates decrease due to sintering when it is reduced at 1500 °C.