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CN-116651199-B - Catalytic filter element and preparation method and application thereof

CN116651199BCN 116651199 BCN116651199 BCN 116651199BCN-116651199-B

Abstract

The invention provides a catalytic filter element, a preparation method and application thereof, wherein the catalytic filter element comprises a filter element main body, and a denitration catalyst is loaded on the outer surface of the filter element main body and has a loading depth towards the inside of the filter element main body; the inner surface of the cartridge body is loaded with a devolatilizing catalyst and has a loading depth to the exterior of the cartridge body. The obtained catalytic filter element can meet the requirement of simultaneously removing NO x and VOCs in complex flue gas, in the same catalytic reaction unit and under the same temperature zone condition, has the removal rate reaching more than 90 percent, has stronger stability, and can simultaneously remove NO x and VOCs for a long time with high efficiency.

Inventors

  • GONG ZIJUN
  • YU JIAN
  • LI CHANGMING
  • YANG JUAN
  • LI JIANLING

Assignees

  • 中国科学院过程工程研究所

Dates

Publication Date
20260508
Application Date
20230718

Claims (20)

  1. 1. The preparation method of the catalytic filter element is characterized by comprising the following steps: Preparing a filter element main body, dripping a solution or emulsion containing a denitration catalyst raw material to the outer surface of the filter element main body, spraying a solution or emulsion containing a VOCs-removal catalyst to the inner surface of the filter element main body after first drying, and roasting after second drying to obtain a catalytic filter element; In the solution or emulsion containing the denitration catalyst raw material, the mass concentration of the denitration catalyst raw material is 20-50wt%; in the solution or emulsion containing the VOCs removal catalyst, the mass concentration of the VOCs removal catalyst is 1-10wt%; The dropping speed is 0.1-0.5 mL.min -1 ·cm -2 ; The dripping time is 30-60 s; the first drying method comprises draining at room temperature at a ventilation place until no liquid drips; the second drying comprises heating and drying, and the temperature of the second drying is 50-120 ℃; The preparation method further comprises the following steps: Before dropwise adding a solution or emulsion containing a denitration catalyst raw material, enabling the filter element main body to load a catalyst carrier; Or respectively adding the catalyst carrier into a solution or emulsion containing a denitration catalyst raw material and a solution or emulsion containing a VOCs catalyst, uniformly mixing, and then using; The catalytic filter element prepared by the preparation method comprises a filter element main body, wherein a denitration catalyst is loaded on the outer surface of the filter element main body, and the denitration catalyst has a loading depth towards the inside of the filter element main body; the load of the denitration catalyst is 2-45wt% calculated by taking the mass of the catalytic filter element as 100 wt%; the load of the VOCs removal catalyst is 0.5-5wt% calculated by taking the mass of the catalytic filter element as 100 wt%; The wall thickness of the filter element main body is 15-25 mm; The loading depth of the denitration catalyst is 20% -90% of the wall thickness of the filter element main body; the sum of the loading depth of the denitration catalyst and the loading depth of the VOCs catalyst is less than or equal to the wall thickness of the filter element main body; the catalytic cartridge further comprises a catalyst carrier distributed in the cartridge body; The denitration catalyst and the VOCs removal catalyst are supported on the catalyst carrier in the corresponding area; and the load capacity of the catalyst carrier is 35-55wt% calculated by taking the mass of the catalytic filter element as 100 wt%.
  2. 2. The method of making according to claim 1, wherein the cartridge body comprises a ceramic fiber cartridge.
  3. 3. The preparation method of claim 1, wherein the denitration catalyst has a loading depth of 3-20 mm.
  4. 4. The method of claim 1, wherein the denitration catalyst comprises any one or a combination of at least two of the oxides of V, W, mo, zr.
  5. 5. The method of claim 1, wherein the devolatilization catalyst comprises any one or a combination of at least two of MnO 2 、CoO x or Pt.
  6. 6. The method of claim 1, wherein the devolatilization catalyst is in the form of a nano-sized powder.
  7. 7. The method of claim 1, wherein the catalyst support comprises any one or a combination of at least two of TiO 2 、Al 2 O 3 or SiO 2 .
  8. 8. The method of claim 1, wherein the denitration catalyst feedstock comprises any one or a combination of at least two of the metal salts of V, W, mo, zr.
  9. 9. The method of claim 1, wherein the devolatilization catalyst comprises any one or a combination of at least two of MnO 2 、CoO x or Pt nanopowder.
  10. 10. The preparation method of claim 1, wherein the solution or emulsion containing the denitration catalyst raw material and the solution or emulsion containing the denitration catalyst are respectively prepared by ammonia water with a mass concentration of 1-10wt%.
  11. 11. The method of preparing a catalyst carrier according to claim 1, wherein the method of supporting a catalyst carrier on the filter element body comprises immersing the filter element body in a solution containing a catalyst carrier, and performing a first drying.
  12. 12. The method of claim 1, wherein the catalyst support comprises any one or a combination of at least two of TiO 2 powder, al 2 O 3 powder, or SiO 2 powder.
  13. 13. The preparation method according to claim 11, wherein the solution containing the catalyst carrier is prepared by using ammonia water with a mass concentration of 1-10wt%.
  14. 14. The method according to claim 11, wherein the mass concentration of the catalyst carrier in the solution containing the catalyst carrier is 50 to 80wt%.
  15. 15. The method of claim 11, wherein the time of the impregnation is 0.5 to 1min.
  16. 16. The method according to claim 1, wherein the second drying time is 6 to 12 hours.
  17. 17. The method according to claim 1, wherein the baking temperature is 300 to 500 ℃.
  18. 18. The method according to claim 1, wherein the baking time is 1 to 3 hours.
  19. 19. The preparation method according to claim 1, characterized in that the preparation method comprises the steps of: (1) Preparing a commercial blank ceramic fiber filter element, wherein the wall thickness of the filter element is 20mm; preparing a solution containing any one or a combination of at least two of catalyst carriers TiO 2 、Al 2 O 3 and SiO 2 , namely dissolving powder of a corresponding industrial catalyst carrier in 1-10wt% ammonia water, and controlling the mass concentration of the catalyst carrier to be 50-80wt%; Preparing a solution or emulsion containing a denitration catalyst raw material, namely uniformly mixing any one or a combination of at least two of V, W, mo, zr metal salts with 1-10wt% of ammonia water, and controlling the mass concentration of the denitration catalyst raw material to be 20-50wt%; Preparing a solution or emulsion containing a VOCs-removing catalyst, namely uniformly mixing any one or a combination of at least two of MnO 2 、CoO x and Pt nano powder with 1-10wt% of ammonia water, wherein the mass concentration of the VOCs-removing catalyst is 1-10wt%; (2) Dipping the ceramic fiber filter element into the solution containing the catalyst carrier for 0.5-1 min to ensure that the loading capacity of the catalyst carrier is 35-55wt%, and draining the dipped filter element at a ventilation position at room temperature until no liquid drops; (3) Then dripping the solution or emulsion containing the denitration catalyst raw material to the outer surface of the drained filter element, controlling the dripping speed to be 0.1-0.5 mL-min -1 ·cm -2 , and dripping for 30-60 s, so that the load capacity of the denitration catalyst is 2-45wt% and the load depth is 3-20 mm; (4) Draining the loaded filter element at a ventilation position at room temperature until no liquid drops, spraying the solution or emulsion containing the VOCs removing catalyst on the inner surface of the drained filter element, and controlling the load amount of the VOCs removing catalyst to be 0.5-5wt% and the load depth to be less than or equal to 3mm; (5) And (3) drying the filter element after the steps at the temperature of 50-120 ℃ for 6-12 hours, and roasting at the temperature of 300-500 ℃ for 1-3 hours to obtain the finished catalytic filter element.
  20. 20. Use of a catalytic filter element according to any one of claims 1 to 19, wherein the use comprises the simultaneous removal of NO x and VOCs.

Description

Catalytic filter element and preparation method and application thereof Technical Field The invention belongs to the field of pollutant purification, and relates to a catalytic filter element, a preparation method and application thereof. Background At present, the atmospheric pollution situation in China is still severe, industrial pollution is transiting from soot type to compound type pollution, and various atmospheric pollutants are often simultaneously present and mutually coupled. Wherein, NO x is one of the most main pollutants in the industrial exhaust flue gas, which can cause serious environmental pollution such as photochemical smog, acid rain and the like and harm human health. It is mainly derived from fuel combustion process in industries of electric power, ferrous metallurgy, coking, cement building materials and the like. With the increasing importance of the country to environmental protection, the pollutant emission of enterprises is increasingly severely limited. VOCs (volatile organiccompounds ) have the characteristics of irritation, durability, high toxicity, photochemical reactivity and the like, and cause serious trouble to natural environment and human production and life. In the flue gas discharged from the typical industries of refuse incineration, metal smelting, coking and the like, NO x and VOCs often exist simultaneously, and not only a large space is required for separately removing each pollutant, but also high operation cost is required. With the increasing emphasis of countries on environmental protection, there is a growing concern over VOCs. At present, in industrial application, NO x in flue gas is treated by adopting an NH 3 selective catalytic reduction (NH 3 -SCR) denitration technology, NH 3 is used as a reducing agent, and a catalyst is used for carrying out a centering reaction on NO x and NH 3 within a temperature range of 150-450 ℃ to finally convert into N 2 and H 2 O. For example, the vanadium-based catalyst has excellent sulfur and water resistance in a smoke environment of 180-450 ℃ and is widely applied to denitration units in the industries of electric power, coking, cement and the like. Catalytic materials currently available for SCR processes include honeycomb bodies that directly shape the catalyst and particulate catalytic materials, and catalytic material supports include flexible catalytic filter bags and rigid catalytic filter elements. The honeycomb catalytic material is suitable for the fields of electric power, coking, sintering and the like with large smoke quantity, and the particle catalytic material is suitable for a diffusion bed, a moving bed reactor and the like. The catalyst material carrier has the functions of denitration and dust removal, the rigid catalytic filter element in the catalyst carrier is suitable for denitration and dust removal of flue gas such as glass, cement, biomass power generation and the like, and the flexible catalytic filter bag is suitable for low-sulfur flue gas such as garbage incineration, solid waste incineration, lime kiln low-sulfur flue gas and the like. Compared with the catalytic filter bag, the catalytic filter core has good mechanical strength and chemical stability in a wider temperature range. In addition, in the process of purifying the flue gas of the catalytic filter element, dust and waste desulfurizing agent are removed through a dust removal compact film on the outer layer of the filter element, SO that the denitration catalyst loaded in the filter element is protected from poisoning of SO 2, alkali, alkaline earth metal and other harmful substances. For the technology of VOCs removal, the catalytic oxidation technology is considered to be an efficient method because of high economic feasibility, low cost and low secondary pollutant production. CN202110562186.X proposes a zoned coated VOC catalyst and a process for its preparation. The VOC catalyst comprises a carrier and a coating coated on the carrier, wherein the coating comprises a front region coating and a rear region coating, the front region coating is positioned at the air inlet end of the catalyst, precious metals Pt and Pd are loaded in the coating and comprise magnesium, aluminum composite oxides Mg-Al 2O3 and cerium dioxide, the rear region coating is positioned at the air outlet end of the catalyst, precious metals Pt and Pd are loaded in the coating and comprise tungsten-aluminum composite oxides W-Al 2O3 and hydrogen type beta molecular sieve, and the conversion efficiency of the catalyst to VOCs pollutants can be improved under the premise of lower precious metal loading. In addition to the VOCs catalysts used in the above-described invention, the classical denitration catalyst vanadium-based catalysts also have the potential and feasibility of removing VOCs. For example, when W or Mo is added to the VO x/TiO2 catalyst, the formation and presence of NO promotes the improvement of VOCs conversion. In the presence of O 2, the oxi