Chemical Looping Combustion (CLC) is a Carbon Capture technology which allows the inherent separation of CO2 having a small energy penalty compared to other existing capture technologies. The process principle was already developed and patented in 1954 by Lewis and Gilliland. However, at that time the intended application of the process was the production of pure CO2. In recent years CLC has attracted attention again as an alternative conversion process for the carbon capture and storage (CCS) technology.

Generally the process consists of two reactors: the air reactor in which the oxygen carrier is laden with oxygen and the fuel reactor where the oxygen carrier supplies the oxygen for fuel combustion. When a gaseous fuel is used the solid oxygen carrier can directly react with the fuel gas, whereas a direct reaction of the solid oxygen carrier with a solid fuel like coal does not at a sufficient rate. Hence the solid fuel must either be gasi ed or a special oxygen carrier has to be used which has the ability of releasing gaseous oxygen within the fuel reactor (i.e. the so called chemical looping with oxygen uncoupling (CLOU). Different designs of for continuously operated CLC units have been developed in recent years. The majority of process designs currently under investigation are systems of coupled  uidized beds. However, the concepts still differ signi cantly in the  ow regimes used in the individual reactors: systems of two coupled circulating  uidized beds as air reactor and fuel reactor, respectively. At TUHH a concept with a two stage fuel reactor has been developed, with increase the combustion ef ciency and to reduce the emission of uncombusted gases.