An investigation into chemical-looping gasification (CLG)of coal with K2CO3 and NiO-decorated Fe2O3 oxygen carrier in a fluidized bed reactor

using steam as the gasification-fluidization medium

was carried out.The reactivity and regeneration of two kinds of Fe2O3 composite oxygen carriers in multi-cycles

as well as the mechanism and kinetics model of the gasification process

were presented.At 920℃

the reactivity order was as follow:Fe4Al6K1>Fe4Al6>Fe4Al6Ni1.X-ray diffraction (XRD)images showed that the Fe4Al6K1 composite oxygen carrier was completely regenerated after 6 cycle redox experiments

and potassium ferrites were formed during the calcinations process

whose structure could boost the reactivity of Fe-based oxygen carrier.Fe4Al6K1 particles were excellent oxygen carriers for chemical-looping gasification of coal.Finally

the peak fitting technique was used to analyze the gasification reaction rate curve describing the reaction mechanism of coal and Fe2O3 composite oxygen carrier.It indicated that complex reactions of CLG included three stages

the reaction between Fe2O3

coal char and steam

the gasification of coal char

and the reaction of Fe3O4 to FeO.