Abstract: Coal-fueled chemical looping combustion was studied from three aspects.In the aspect of oxygen carriers,the gas-solid reaction of carriers was studied.Multi-crystal Fe with smooth surface was used as the reactant to eliminate the effect of pore structure.The morphology of solid products was observed under a scanning electron microscope.The problem of directly observing the product morphology was solved.A rate equation theory was developed to describe the macroscopic kinetics based on the nucleation and growth of solid product from molecular level.A model of interaction force between active components and inert supports was developed.The method of improving the reactivity of natural limonite by introducing foreign ions was proposed.In the aspect of interaction between coal and oxygen carriers,the effect of volatiles and ash on oxygen carriers was addressed.The match of char gasification rate and reduction rate can be achieved through catalytic gasification.Fragmentation,attrition,and segregation of coal particles caused the incomplete gas conversion in the fuel reactor.In the reactor aspect,a three fluidized beds reactor with dual circulating loops was built.A steady operation of 140 h in hot mode was accomplished.The concepts of downer reactor,low temperature CLC,and direct CLC were proposed for converting the un-reacted gases.