Rare Earth Metal Modified Kaolin Catalysts In The Reduction Of SO₂by CO

In recent years, air pollution has been becoming more and more serious with the the increase of sulphur dioxide (SO2) emissions with the development of industry. At present, desulphurization technology mainly includes dry desulfurization, wet desulfurization and semi-dry desulfurization by technological property. In this study catalytic reduction technology has studied as it has less secondary pollution, and the by product is sulfur, which can be reused in the industry. However, the currently used catalysts are usually expensive. The key point to solve this problem is to develop high-efficient steady catalyst. In this paper, Kaolin was studied as carrier as it is cheap, clean and easily available, and lanthanum and cerium were studied as active components. Finally, the optimum reaction conditions of SO2reduction with CO were studied.The results indicated that:(1) The resultant rare earth metal supported Kaolin catalysts without acidic and alkaline modification had the conversion near100%under the condition of500℃, La loading reached7%as for La/Kaolin, and had the conversion99%under the condition of550℃, Ce loading reached3～10%as for Ce/Kaolin. For La-Ce/Kaolin catalyst, under the condition of500℃, GHSV=9000～25000h-1, C/S=2:1～3:1, desulphurization rate reached100%. Especially, compared with catalysts carried with La or Ce, the mixed component showed higher activities.(2) XRD analysis showed that the active substances of Ce/Kaolin catalyst were both CeO2before or after the desulfurization, however for La carried catalyst, the active substance was La2O3before the reaction, and partly changed into La2O2S after desulfurization. In addition, the calcination temperature affected the catalyst surface structure and reduction property, the surface structure changed into oxidation state from the initial nitrate state with the increase of calcinations temperature from room temperature to300/500℃.