The Characteristic Reaction Of WO₃/TiO₂-ZrO₂ Series High-temperature SCR DeNO_X Catalysts And Its Application

Catalysts are the key to Selective Catalytic Reduction method which is widely used in flue gas denitration method, V2O5-WO3（MoO3）/TiO₂ as the most generally used catalysts in practice which operating temperature range is so narrow（300-400℃） that cann’t be used for waste incinerators and gas turbine with the gas temperature is over 500℃. Conventional catalyst will be easily sintered and the crystal form of TiO₂ will be changed in high-temperature flue gas, then the catalysts are inactivated. In order to applying SCR technology to high-tenmperature gas, a new kind of catalysts are needed to be developed.The W03/TiO₂-ZrO₂ SCR catalysts were prepared for high temperature （>500℃） denitrification, within the WO3 as the active component and the TiO₂-ZrO₂ as the carrier. The catalysts were characterized by XRD. Experiments were performed to reveal the effects of TiO₂-ZrO₂ composition, WO3 loading and high temperature treatment on the activities of the WO3/TiO₂-ZrO₂ catalysts. The results indicated that the WO3/TiO₂-ZrO₂ catalysts were thermally stable, the crystal phase structures were not changed after high temperature treatment at 800℃, and the denitrification efficiency was only decreased a little. The two W03/TiO₂-ZrO₂ catalysts within the TiO₂:ZrO₂=7:3 or 0:10（mass ratio） and 20% WO3 exhibited the best SCR performance, and they could be used for the high temperature denitrification process.The denitrification efficiency was raised by means of adding V2O5 to the catalyst, but the amount of V2O5 can’t be more than 0.5wt% to avoide the NH3 and SO₂ be oxidized. Considering the process of producting catalyst support is so complex that the industrial application is difficult, this paper study on the catalysts with carrier of TiO₂-ZrO₂（0:10） namely ZrO₂ to make it industrialization. At first, the influence of preparation of ZrO₂ to the denitrification efficiency was studied, then, plate catalysts were prepared by adding excipients to formulas, in the same time, the denitrification efficiency was tested, the results indicated that they could be used for the high temperature denitrification process.