Continuous Operation of Interconnected Fluidized Bed Reactor for Chemical Looping Combustion of CH4 Using Hematite as Oxygen Carrier

Chemical looping combustion (CLC) is a novel technology for CO2 capture with low energy penalty. This technique involves the operation of the interconnected fluidized bed reactors, within which solid oxygen carrier particles circulate to provide active lattice oxygen for fuel combustion. An interconnected fluidized bed reactor was tested using natural hematite as oxygen carrier and CH4 as fuel. The thermal power was between 1.00 and 1.50 kW(th) in the continuous operation of 100 h. During the operation, the CLC unit showed a good performance, in which the gas leakage varied between 1.81% and 3.20%, and the CH4 conversion of 81.3% at maximum and the carbon capture efficiency of over 90% were attained. The effects of operational parameters on the performance of the new CLC reactor were investigated. The results indicated that the CH4 conversion and CO2 yield were influenced by the reactor temperature, bed inventory per unit thermal power, and the flow rate of the fluidizing gas agent in the fuel reactor. After the whole tests, no sintering and agglomeration of used particles were observed, and the thermogravimetric analyzer results of used samples showed the reactivity of oxygen carrier was well maintained.