Preparation And Characterization Of SCR Catalyst By Industrial Titanium Tungsten Powder

The selective catalytic reduction （SCR） is best developed and used for the controlof NOx emissions in fuel combustion from stationary sources. As the core part of thecatalyst, it depends on catalytic activity and cost of the technology. The thesisresearched the effect of V2O₅concentration, WO₃concentration, impregnationtemperature, calcination temperature, K₂O concentration, adding mode of Na₂O andFe₂O₃to catalytic activity with catalysts prepared by domestic and imported industrialtitanium tungsten powder. Then the difference between domestic and importedindustrial titanium tungsten powder was analyzed, which provide theory evidence forproducing high quality SCR catalysts prepared by domestic industrial titanium tungstenpowder.Ingredient optimization study showed that the V2O₅-WO₃/TiO₂catalysts preparedby domestic industrial titanium tungsten powder with0.3%V2O₅and4.48%WO₃hadbetter NO removal effiency （above95%during200⁴50℃）.Compared with domesticand imported industrial titanium tungsten powder, the surface area of WO₃-TiO₂catalysts decreased, which indicated that WO₃-TiO₂catalysts were sintered duringpreparation process.The impregnation and calcination temperature had an obvious impact on thestructure and activity of catalysts prepared by domestic and imported industrial titaniumtungsten powder．Higher impregnation temperature （80℃） was beneficial to enlarg thesurface area and improve catalytic activity, so that the catalysts prepared by domesticindustrial titanium tungsten powder were close to imports.While higher calcinationtemperature would lead to increase micropore volume and improve catalytic activity.But it would also decrease the surface area, for instance, the surface area of catalystprepared by domestic industrial titanium tungsten powder was from79.65m²·g（-1）to53.88m²·g（-1）and catalyst prepared by imported industrial titanium tungsten powder wasfrom78.24m²·g（-1）to54.62m²·g（-1）.The influence of metal oxide added to V2O₅-WO₃/TiO₂catalysts prepared bydomestic and imported industrial titanium tungsten powder on catalytic activity wasresearched. It showed that catalysts prepared by imported industrial titanium tungstenpowder were superior to domestic catalysts in resisting to poison. Added K₂O toV2O₅-WO₃/TiO₂catalyst, catalytic activity of1.0K₂O-V2O₅-WO₃/TiO₂catalyst prepared by domestic industrial titanium tungsten powder was reduced to95%during300³50℃，but catalytic performance of catalyst prepared by imported industrialtitanium tungsten powder was hardly affected, which was higher than99%. AddedNa₂O to V2O₅-WO₃/TiO₂catalyst, change rule of catalytic activity of V2O₅-WO₃/TiO₂catalysts prepared by different methods with different concentration of Na₂O wasopposite; Added Fe₂O₃to V2O₅-WO₃/TiO₂catalyst, catalytic activity of20Fe₂O₃-V2O₅-WO₃/TiO₂catalyst prepared by multistep impregnation method wassignificantly reduced during350⁴50℃, but catalytic activity of catalyst prepared byone-step impregnation method hardly affected the catalytic performance.