CLC (Chemical Looping Combustion) cycle is one of the innovative power generation cycles using oxy-combustion, where the combustion chamber is replaced by a chamber with two compartments between which flows a metal oxide such as NiO. In one of the chambers, the air is oxygen-depleted due to oxidation of the metal. In the other, the oxide is reduced and the oxygen released burns with fuel. The reactor model we built is purely global. We consider that the temperature and composition of the depleted air are set. It then becomes possible to determine the flow of oxygen transferred between the two reactor compartments.