Research On Denitrification Performance Of Titanium-Based SCR Catalysts

Nitrogen oxides (NOx) are recognized as a major source of air pollution in the world. The selective catalytic reduction of NOx with NH3 as reductant is most efficient among the technologies abating NOx in flue gas at present. In order to study and explore high effective SCR catalyst, author take a theoretical and experimental research about titanium-based catalyst preparation,their active component changing,reaction parameters changing for effect of NO removal.Different components of V2O5/TiO2. V2O5-WO3/TiO2,CeO2/TiO2,CeO2-MnO2/TiO2,CeO2/TiO2-ZrO2 catalysts have been prepared by the impregnation method. On the catalytic activity testing, the effect of catalytic activity for active ingredients and additives content on the catalytic changing have been studied. The results show that, the ratio of 1% V2O5/TiO,1.2%V2O5 /TiO2 and 1.2%V2O5-10%WO3/TiO2 are the best active catalysts for vanadium department. When CeO2 loading content is more than 10% and space velocity is 30000h-1, NO removal efficiency can be kept in the range of 94.27%-99.63% at 250-450℃over CeO2/TiO2-ZrO2 catalyst.Influence of SO2 on denitrification performance of catalyst have been studied. The activity of V2O5/TiO2 and CeO2/TiO2-ZrO2 have been affect by SO2, but the affect is little, it is indicating that the catalysts have a ability of resistance to SO2 poisoning.V2O5/TiO2 catalysts add additives of WO3, which can improve the performance of resistance to sulfur, denitrification efficiency is obvious higher than V2O5/TiO2 catalyst, when SO2 and water vapor exist simultaneously, The NO removal capacity of CeO2/TiO2-ZrO2 have been affect by SO2, NO removal efficiency increases with rising resction temperature. Existing of water vapor which is propitious to resistance to SO2 poisoning over CeO2/TiO2-ZrO2 at high temperature stage.Influence of loading potassium over V2O5/TiO2 catalyst have been studied. The results show that, V2O5/TiO2 catalyst have been strong poisoned by potassium, the NO removal efficiency decreases with the increasing loading of potassium. When V2O5/TiO2 catalysts add additives of WO3, V2O5/TiO2 catalytic activity is improved and NO removal efficiency is also increased after adding to WO3, it show that WO3 have capability to resist potassium poisoning.The effect over V2O5/TiO2 and CeO2/TiO2-ZrO2 catalysts by reaction temperature, space velocity, O2 concentration, NH3/NO ration, NO initial concentration have been studied. With space velocity decreasing, NH3/NO ration, O2 concentration, NO initial concentration increasing, denitrification rate show an increasing trend.Dynamic analysis of V2O5-WO3/TiO2 have been carried out. In the case of removing influence of internal and external diffusion, NH3/NO ration beyond to 1, reaction order of NO being 1.0493 and reaction order of O2 being 1.1366 have been attained by computing, thus reaction rate equation of V2O5-WO3/TiO2 catalyst can be attained.