Preparation for NOx Series Catalyst with Selective Catalytic Reduction at High Temperature

When the temperature of waste gas is higher than 500℃, Vanadium catalyst directly oxidation of NH₃is significantly enhanced, resulting in a significant reduction in the removal rate of NOx. Under high temperature, the WO_3-TiO₂ system has better catalytic activity and high temperature stability compared to the traditional V₂0₅-W0₃/TiA system. A method for preparing WO_3-TiO₂ catalyst is described in this paper, steps are as follows:

1. Mixing ethanol, tetrabutyl titanate and glacial acetic acid by volume ratio 2:1:1, get solution A;
2. Dissolve ammonium paratungstate in the oxalic acid solution with mass concentration of 5% to obtain solution B, in which the mass ratio of ammonium paratungstate: oxalic acid is 1.6:1;
3. Drop a certain amount of solution B into solution A slowly, in which the quality ratio of ammonium paratungstate and tetrabutyl titanate is 0.029:1~0.11:1, stirring constantly to form a uniform and stable sol;
4. Static settling for 40~60 hours, dry in an oven at the temperature of 50~ 60℃ for 16~30 hours to get a dry gel;
5. Grind the dry gel in a mortar for 30~50 minutes, then calcine in the muffle furnace at 550~650 ℃ for 3~6 hours, get the high temperature SCR catalyst WO_3-TiO₂ with the active component WO₃.

The catalyst in this paper has the advantages like: simple process and low production cost, with high active at the temperature of 450~550℃, higher denitrification rate, long service life, high thermal stability.