The FGD process of mixture of lime and Fe2O3 is analyzed by using TGA in this paper.It is shown that Fe2O3 can’t react with SO2 from 200℃ to 700℃.The desulfurization efficiency of lime is improved with temperature rising.SO2 can be captured by lime at 600℃ or 700℃. But there is almost no desulfurization reaction taking place with lime when temperature is below 500 ℃. The behavior of lime in desulfurization reaction does not change with added Fe2O3. But the conversion rate of CaO is greatly improved:the more Fe2O3

the higher the conversion rate.Fe2O3 acts as an activator more than a catalyst in the desulfurization reaction with lime.Fe2O3 acts as the “activation center”around which CaO particles are sulfurized.The new dispersal formation mode of product differs from the compact layer that used to be. And the pore structure of product layer on the surface of lime particles is optimized

which makes SO2 penetrate into core parts of lime more easily. As a result

the desulfurization reaction is developed deeper into the core parts of absorbent.