Reduction kinetics of cobalt oxide powder by methane in a fluidized bed reactor

In the present work, cobalt oxide in powder form with an average particle size of 100 pm has been reduced by methane used as a reducing agent in a batch fluidized bed reactor. The reaction was carried out in the temperature range of 800-950 degrees C with mole fractions of methane at the values of 0.15, 0.3 and 0.5. Argon was used as a fluidizing gas with a velocity of 1.3 times the minimum fluidization velocity. Approximately 4 g of cobalt oxide powder has been used in a laboratory scale fluidized bed reactor with 18-mm inner diameter and 1.1 m length. The ratio of the bed height to the bed diameter, after fluidization, was approximated near unity. The chemical reaction kinetics has been found as the rate limiting step under the experimental conditions used. The activation energy and the order of reaction have been calculated as 120 kJ/mol and 0.9, respectively, on the basis of the shrinking unreacted core model. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.