Development And Application Of V₂O₅-WO₃/TiO₂ Catalyst For Selective Catalytic Reduction Of DeNOx

V2O5-WO3/TiO2 catalysts were developed for selective catalytic reduction (SCR) of NOx in the exhaust of diesel engine. NOx conversion and the amount of NOx emission were determined with the bench of diesel engine. The diesel engine with the SCR catalyst can meet Euro 4 emission regulations.The SCR catalyst developed were composed of TiO2 as carrier, V2O5 as active component and WO3 as promoter. By the simulation evaluation of the small-sample catalyst, the optimal coating composition of SCR catalyst was obtained, and various factors such as water vapor, SO2, space velocity, NH3/NO ratio and aging conditions were investigated over V2O5-WO3/TiO2 catalyst. The results showed that NOx conversion of more than 85% was achieved under the conditions of V2O5 content of 3wt%, space velocity of 30000h-1, NH3/NO ratio of 0.8-1.0, reaction temperature of 200-450℃.Cordierite monolith SCR catalysts were prepared based on the result of small-sample catalyst. This catalyst was evaluated by the bench of 12 L diesel engine according to the ESC test cycles of GB17691-2005. Effects of urea injection amount, space velocitiy and fuel quality on NOx conversion were investigatedin the exhaust of diesel engine. Theresults showed that the emission of this type of diesel engine could meet Euro 4 emission regulations under the conditions of Euro 4 fuels, urea injection amount of 5% fuel consumption and space velocity of 30000 h-1.The whole emission performances were compared between ourcatalyst and the foreign catalystunder the same conditions. The results showed that the catalytic performance of our catalyst was equivalent to that of the foreign catalyst, which satisfied the requirements of replacing foreign catalyst and will bring great social benefit and economic benefit.