(677e) Oxidation/Reduction Kinetics of Fe Particles in a ZiO2/ SiO2 Fluidized Bed

Reaction kinetics are crucial in the design of thermochemical reactors for hydrogen production. This paper investigates the reaction kinetics of various mass percentages of elemental iron (Fe) in a mixture of nonreactive particles, consisting of powdered zirconia (ZiO₂) and silica (SiO₂), when under a stream of H₂O. In addition, the oxidized bed was reduced under a stream of carbon monoxide (CO), and the reaction kinetics were characterized..  The overall cycling characteristics of an Fe-based system were investigated..  Temperatures well above the sintering temperature of the powdered iron particles alone were investigated due to the sintering inhibition provided by the nonreactive ceramic particles. During oxidation, a stream of H₂O was passed through the powder bed at temperatures ranging from 550-950°C.  Reduction was performed using a stream of carbon monoxide (CO) at temperatures from 800-1000°C, with the minimum to avoid carbon depositing (due to the Boudouard reaction) in the powder bed. Products were measured via a mass flow meter and mass spectrometer during oxidation and reduction, respectively. Powder bed weight was used to close the reactant/product mass balance.   Average hydrogen production rates over the first minute of reaction of 0.1-0.2 SLPM per gram of reactive material were achieved.  This work characterizes the reaction kinetics of a readily available iron particle reactant in Fe-Fe₃O₄ redox reactions, using water as an oxidizing agent and CO as a reducing agent.