Experimental and Simulated Investigation of Chemical Looping Combustion of Coal with Fe2O3 based Oxygen Carrier

Reaction of Fe2O3 oxygen carrier (OC) with a Chinese bituminous coal was experimentally investigated using thermogravimetric (TGA)-differential thermal analysis (DTA) and then thermodynamically simulated based on the minimization of Gibbs free energy, with focuses on the effect of both oxygen excess number Φ and the inclusion of inert support Al2O3 to Fe2O3. TGA-DTA investigation indicated that sufficient supply of Fe2O3 was beneficial to the full conversion of PDS with its characteristic temperatures shifted to lower temperature, but the inclusion of Al2O3 to Fe2O3 hindered the reaction of Fe2O3 with PDS at the final reaction stage. And thermodynamic simulation of the reaction of PDS with Fe2O3 at Φ=1 revealed that at the temperature of interest for chemical looping combustion (CLC) 900oC, full conversion of PDS was reached and increasing oxygen excess number Φ was beneficial to promote the sufficient conversion of PDS as well as to reduce more Fe2O3 to Fe3O4. But the inclusion of Al2O3 to Fe2O3 resulted in the interaction between the reduced Fe2O3 with Al2O3 to FeAl2O4 and hindered the full regeneration of the reduced Fe2O3 with air.