Search

CN-122006697-A - Denitration catalyst with high specific surface area as well as preparation method and application thereof

CN122006697ACN 122006697 ACN122006697 ACN 122006697ACN-122006697-A

Abstract

The invention relates to the technical field of oilfield chemistry, in particular to a high specific surface area denitration catalyst and a preparation method and application thereof, wherein the high specific surface area denitration catalyst comprises, by mass, 55% -80% of a titanium-silicon composite oxide carrier, 1.5% -5.0% of an active component, 5% -15% of a promoter and 8% -25% of a modifying component, the titanium-silicon composite oxide carrier has a molar ratio of Si to Ti of 0.05-0.15:1, the catalyst takes the titanium-silicon composite oxide as the carrier, loads active components vanadium oxide, promoter tungsten oxide and a modified component cerium zirconium solid solution, the carrier is prepared by combining a step sol-gel method with a supercritical drying process, and the active and the promoting components are loaded by an impregnation method, so that the denitration catalyst with high specific surface area, high denitration efficiency and excellent sulfur-poisoning resistance can be finally obtained, and can be widely applied to flue gas denitration scenes in industries such as steel and the like.

Inventors

  • YANG CHENG
  • LI FUYONG
  • LU LIN
  • PANG YANG
  • ZHANG WENBIN
  • TAO JIN
  • ZHANG CHENG

Assignees

  • 新疆中泰国信节能环保有限公司

Dates

Publication Date
20260512
Application Date
20251225

Claims (10)

  1. 1. The high specific surface area denitration catalyst is characterized by comprising, by mass, 55% -80% of a titanium-silicon composite oxide carrier, 1.5% -5.0% of an active component, 5% -15% of a cocatalyst and 8% -25% of a modifying component, wherein the molar ratio of Si to Ti in the titanium-silicon composite oxide carrier is 0.05-0.15:1.
  2. 2. The high specific surface area denitration catalyst according to claim 1, characterized by having a specific surface area of 280m 2 /g to 350m 2 /g of the titanium-silicon composite oxide support.
  3. 3. The high specific surface area denitration catalyst according to claim 2, characterized in that the active component is V 2 O 5 ; or/and, the cocatalyst is WO 3 ; Or/and the particle size of the modifying component Ce 0.6 Zr 0.4 O 2 ,Ce 0.6 Zr 0.4 O 2 is 15nm to 30nm.
  4. 4. A high specific surface area denitration catalyst according to any one of claims 1 to 3, characterized in that the high specific surface area denitration catalyst is produced by the steps of: Step one, drying the titanium-silicon composite sol under the supercritical condition of CO 2 , and roasting the dried product to obtain a titanium-silicon composite oxide carrier; Step two, ammonium metavanadate is dissolved in oxalic acid solution, ammonium tungstate and Ce 0.6 Zr 0.4 O 2 powder are added, and impregnation liquid is obtained after dispersion; And thirdly, soaking the titanium-silicon composite oxide carrier in a soaking solution, and drying and roasting the soaked product to obtain the high specific surface area denitration catalyst.
  5. 5. The high specific surface area denitration catalyst according to claim 4, wherein in the first step, the titanium-silicon composite sol is prepared by the following steps: dissolving tetrabutyl titanate in ethanol, adding the ethanol into a citric acid solution, and uniformly stirring to obtain titanium sol; Dissolving tetraethoxysilane in ethanol, dripping the ethanol into titanium sol, regulating the pH to 3.5-4.5 by ammonia water, and uniformly stirring to obtain the composite sol.
  6. 6. The high specific surface area denitration catalyst according to claim 5, characterized in that the volume ratio of tetrabutyl titanate to ethanol is 1:3 to 1:5, the mass concentration of citric acid solution is 10% to 15%, and the amount of citric acid solution is 0.5 to 1.5 times that of ethanol; or/and the volume ratio of the tetraethoxysilane to the ethanol is 1:20 to 1:30.
  7. 7. The high specific surface area denitration catalyst according to any one of claims 4 to 6, characterized in that in the first step, the supercritical condition of CO 2 is that the temperature is 31 ℃ to 35 ℃, the pressure is 7.5mPa to 8.0mPa, the drying is carried out for 3h to 6h, the roasting temperature is 550 ℃ to 600 ℃, and the roasting is carried out for 4h to 6h; Or/and, in the second step, ce 0.6 Zr 0.4 O 2 is prepared by a coprecipitation method, the precipitant is ammonium bicarbonate, and Ce 0.6 Zr 0.4 O 2 is obtained after the coprecipitation product is roasted, wherein the roasting temperature is 500-550 ℃, and the roasting time is 3-4 hours; or/and, in the second step, the molar ratio of the ammonium metavanadate to the ammonium tungstate to the oxalic acid is (1.5 to 2.5): (2 to 2.5): (3.5 to 4.5); or/and, in the third step, the soaking temperature is 50-70 ℃ and the soaking time is 3-5 hours; Or/and, in the third step, drying is carried out at 100-120 ℃ for 10-15 h, and roasting is carried out at 450-500 ℃ for 5-8 h.
  8. 8. A method for preparing the high specific surface area denitration catalyst according to claim 1 or 2 or 3 or 5 or 6 or 7, characterized by comprising the steps of: Step one, drying the titanium-silicon composite sol under the supercritical condition of CO 2 , and roasting the dried product to obtain a titanium-silicon composite oxide carrier; Step two, ammonium metavanadate is dissolved in oxalic acid solution, ammonium tungstate and Ce 0.6 Zr 0.4 O 2 powder are added, and impregnation liquid is obtained after dispersion; And thirdly, soaking the titanium-silicon composite oxide carrier in a soaking solution, and drying and roasting the soaked product to obtain the high specific surface area denitration catalyst.
  9. 9. Use of a high specific surface area denitration catalyst according to any one of claims 1 to 7 in flue gas denitration.
  10. 10. The use of a high specific surface area denitration catalyst according to claim 9 in flue gas denitration, characterized in that the application conditions are that the flue gas temperature is 200 ℃ to 400 ℃, the airspeed is 15000h -1 to 30000h -1 , the molar ratio of NH 3 and NO x in the flue gas is 0.9 to 1.1, and the concentration of NO x in the flue gas denitration inlet is 500mg/m 3 to 1500mg/m 3 .

Description

Denitration catalyst with high specific surface area as well as preparation method and application thereof Technical Field The invention relates to the technical field of environmental catalysis, in particular to a high specific surface area denitration catalyst and a preparation method thereof, and application of the high specific surface area denitration catalyst in medium-low temperature flue gas denitration. Background Nitrogen oxides (NO x) are main atmospheric pollutants discharged by industries such as thermal power, steel, chemical industry and the like, and can cause environmental problems such as acid rain, photochemical smog and the like. Selective Catalytic Reduction (SCR) technology is currently the most mature and widely used denitration technology, and the core of the technology is a denitration catalyst. The Chinese patent document with the publication number of CN103586017A discloses a preparation method of titanium tungsten powder for a flue gas denitration catalyst and a product prepared by the same, and specifically provides titanium tungsten powder for the flue gas denitration catalyst, wherein the method comprises the steps of (1) preparing metatitanic acid, respectively adding an oxygen titanium sulfate solution and a dispersing agent I into a constant-temperature reaction kettle, dropwise adding a carbonate aqueous solution into the constant-temperature reaction kettle under the stirring condition, regulating a solid substance obtained by mixing the solution in the constant-temperature reaction kettle, washing and drying the solid substance to obtain metatitanic acid particles; and (2) preparing composite particles, namely crushing the meta-titanic acid particles prepared in the step (1), dissolving the crushed meta-titanic acid particles in a second reaction kettle filled with a tungsten solution, adding tween 80 into the tungsten solution, heating to 80-90 ℃ until moisture in the second reaction kettle is basically evaporated to dryness, and (3) carrying out aftertreatment, namely drying the composite particles, and calcining the dried composite particles at 500-600 ℃ for 3-5 hours to obtain the product. The Chinese patent document with publication number of CN102166514A discloses a preparation method of a structured flue gas denitration catalyst, the prepared catalyst and application thereof. The method comprises the steps of preparing titanium dioxide powder containing WO 3 by premixing TiO 2 powder with oxalic acid solution containing ammonium metatungstate, mixing the prepared titanium dioxide powder, an inorganic binder, a plasticizer, glass fibers and sesbania powder according to a specific mass ratio, adding oxalic acid solution of ammonium metavanadate and aqueous solution of cerium nitrate, mixing, adding ammonia water to adjust the pH value to 9-10, aging for 5-10 days, coating the aged pug on a stainless steel net, rolling, forming, and finally drying and roasting to obtain the plate-type structured V 2O5/TiO2 -based denitration catalyst. At present, the existing SCR denitration catalyst takes TiO 2 as a carrier to load components such as V 2O5、WO3. The traditional TiO 2 carrier has low specific surface area (generally less than or equal to 150m 2/g), so that the dispersibility of active components is poor, and the low-temperature activity (200-300 ℃) and sulfur poisoning resistance of the catalyst are insufficient. In addition, although the specific surface area of the partially modified carrier can be improved, the preparation process is complex, the cost is high, and the industrialized application is difficult. Therefore, it is of great importance to develop a denitration catalyst which has high specific surface area, high activity, excellent sulfur resistance and simple preparation. Disclosure of Invention The invention provides a high specific surface area denitration catalyst and a preparation method thereof, overcomes the defects of the prior art, and improves the specific surface area, activity and sulfur resistance of the catalyst by optimizing the carrier composition and the preparation process and combining the introduction of modified components. The high specific surface area denitration catalyst is realized by adopting the following measures, and comprises, by mass, 55% -80% of a titanium-silicon composite oxide carrier, 1.5% -5.0% of an active component, 5% -15% of a cocatalyst and 8% -25% of a modifying component, wherein the molar ratio of Si to Ti in the titanium-silicon composite oxide carrier is 0.05-0.15:1. The following are further optimizations and/or improvements to one of the above-described inventive solutions: The specific surface area of the titanium-silicon composite oxide carrier is 280m 2/g to 350m 2/g. The active component is V 2O5. The cocatalyst was WO 3. The particle size of the modifying component Ce 0.6Zr0.4O2,Ce0.6Zr0.4O2 is 15nm to 30nm. The high specific surface area denitration catalyst is prepared by the following steps: Step one