Study Of NH₃-SCR Over Thermally Treated Natural Siderite

Currently,the air pollution has became a serious problem,and nitrogen oxide?NO_X?is one of the causes of many air pollution.With the rapid development of industry and the increasing emission amount of NOx,the control of NO_X becomes more and more important.Catalyst is a crucial factor for the Selective Catalytic Reduction technology,which is widely used to denitration from flue gas.Therefore,many researchers hope to seek a kind of low-temperature,efficient,low-cost and environmentally-friendly catalyst.In this paper,Fe-Mn oxide catalysts were prepared by using natural siderite,and the denitration activity of the catalysts was studied.Meanwhile the physicochemical property,kinetic and poison-resistance of catalyst were investigated utilizing XRF,XRD,TPD,FT-IR and so forth.And the following conclusions are summarized:?1?Fe-Mn oxide catalysts with nano-structures can be prepared by heat treatment of natural siderite.The effect of thermal treatment temperature on SCR performance was evaluated.When the reaction temperature was between 200 ^oC to 400 ^oC,the NO conversion of S500 was 100%,while the N₂ selectivity was over 69%.The characterization results showed that S500 has big specific surface area,strong surface acidity,plentiful active component and surface adsorptive oxygen.?2?The SCR kinetic study of S500 was carried out.The results show that ER mechanism and LH mechanism occured simultaneously during the detration process.And the reaction constant,such as k_SCR-ERCR-ER and k_SCR-LH,increased with the increased reaction temperature.?3?Alkali metal,SO₂ and H₂O can availably restrain the denitration activity of the catalysts.Alkali metal can decrease the specific surface area,the number of acid sites and active ingredient.The formation of ammonium sulfate on catalysts surface and sulfating of active center atoms are caused by sulfur dioxide in flue gas.The inhibition effect of water on the low-temperature SCR activity is reversible.