The iron-based oxygen carriers with Al2O3 as an inert prepared by mechanical mixing were studied on thermal gravimetric analyzer(TGA).Through the thermograms reduced by CH4

it was found that there was severe carbon deposition which even caused the mass curve to increase during reduction process. The concentration of reducing gas had a strong effect on the reaction rate as well as the degree of carbon deposition. At the same mass loss

higher concentration of the gas fuel tends to lead higher reaction rate while less carbon deposition. In addition

as the newly-generated carbon can be oxidized when introduced O2

the amount of CO2 during oxidation process can be applied to compare the level of carbon formation. With the redox cycles increased

the reaction was almost stable while the formation of carbon had a slightly downward tendency. Through analysis of the products with carbon deposition by X-ray diffraction and scanning electron microscope

there was Fe3C generated and the other part of C existed on the carrier in the form of carbon filaments.