Research On SCR Denitration Of Alumina Roasting Flue Gas

As we known,nitrogen oxides are one of the main pollutants in the atmospheric environment.Selective catalytic reduction（SCR）is one of the most widely used and most promising methods for removing NO_x from fixed source flue gas.In recent years,with the innovation of technology in the thermal power industry,the emission status has begun to bear fruit,and the non-power industry NO_x emission standards are becoming more and more strict.The NO_x in the non-ferrous metal industry is urgently needed to be solved.At present,the annual output of alumina in China has been increasing year by year.There is no mature NO_x treatment technology in this industry.SCR denitration technology is widely used due to its high activity,high denitration efficiency and no by-products.The catalyst is the core of the whole SCR denitration technology.At present,the catalyst V₂O₅-WO₃/TiO₂ is usually used in high-temperature,high-dust flue gas passages,and its denitration performance is easily reduced by various alkali metal components in fly ash,and alkali is used in different applications.The existence forms of metals are quite different.It is important to study the performance of denitration catalysts under different flue gas components and to study the poisoning rules of catalysts.It is very important to stabilize the operation of the catalysts,and how to adjust the formulation based on the existing catalyst formula.Better anti-poisoning capacity is also important for prolonging catalyst life.And the alumina calcining flue gas has the characteristics of high water content（30%）,SO₂,and Al₂O₃ alkali dust.Combined with the SCR denitration technology in the power industry,this paper mainly studied on the applicability of V₂O₅-WO₃/TiO₂catalysts in the alumina industry and the modification of catalysts.In this paper,the V₂O₅-WO₃/TiO₂ catalyst was used as the research object,and the catalysts doped with different forms of alkali metal Al₂O₃,CaO,Na₂O and K₂O were studied.Based on the activity test,XRD,BET,NH₃-TPD.The catalysts were characterized by H₂-TPR,XPS and DFT,and the influence of different alkali metals on the catalyst was obtained.It is characterized by TPD and TPR that the doped of alkali metal reduces the number of acid sites,decreases the adsorption capacity of NH₃,and reduces the reactivity of the adsorption site and the reduction site,thus reducing the denitrification activity of the catalyst.In addition,the modification of the low V catalyst is carried out to improve the water and sulfur resistance of the catalyst at a low V content.