Influence of the oxidation step on the behaviour and the performances of an oxygen carrier in fixed bed reactor

Chemical Looping Combustion is a promising technology for clean power generation with integrated CO2 capture. In this process the oxygen required for combustion is provided by a metal oxide. This work deals with the development of an experimental procedure to study performances of an oxygen carrier during oxidation/reduction cycles and the influence of the oxidation step on its behaviour. Tests were performed in a laboratory fixed bed reactor, with NiO/NiAl2O4, a promising oxygen carrier, and CO as fuel. Two different protocols of oxidation were studied. Results reveal that the oxidation step conditions can change the performances of the oxygen carrier. A significant decrease in total reduction capacity was observed using the regeneration step at high temperature due to structural changes in particles. SEM analysis reveals that particle surface contains different crystallites according to this procedure. With the second procedure ( oxidation in temperature ramp), nickel is partially agglomerated.