Catalytic filter element and method of making and using same

Abstract

The application provides a catalytic filter element and a preparation method and application thereof, the catalytic filter element comprising a filter element main body, a denitration catalyst being loaded on an outer surface of the filter element main body and having a loading depth to the inside of the filter element main body, and a VOCs removal catalyst being loaded on an inner surface of the filter element main body and having a loading depth to the outside of the filter element main body. The obtained catalytic filter element can meet the demand for simultaneously removing NO x and VOCs in complex flue gas in the same catalytic reaction unit under the same temperature zone condition, the removal rate reaches more than 90%, and the catalytic filter element has strong stability and can simultaneously remove NO x and VOCs for a long time and with high efficiency.

Description

Technical Field

[0001] This invention belongs to the field of pollutant purification, and relates to a catalytic filter element, its preparation method and application. Background Technology

[0002] Currently, my country's air pollution situation remains severe. Industrial pollution is transitioning from coal-smoke type to complex pollution, with multiple air pollutants often coexisting and coupling with each other. Among them, NO... x NO is one of the most significant pollutants in industrial flue gas emissions, causing serious environmental pollution such as photochemical smog and acid rain, and endangering human health. It mainly originates from fuel combustion processes in industries such as power generation, steel metallurgy, coking, and cement building materials. With increasing national emphasis on environmental protection, enterprise pollutant emissions are subject to increasingly stringent restrictions. VOCs (volatile organic compounds) are characterized by their irritant properties, persistence, high toxicity, and photochemical reactivity, causing serious problems for the natural environment and human production and daily life. In the flue gas emitted from typical industries such as waste incineration, metal smelting, and coking, NO... x Pollutants often coexist with VOCs, and removing each pollutant individually requires not only a large space but also high operating costs. With the increasing emphasis placed on environmental protection by the government, attention to VOCs is gradually increasing.

[0003] Currently, the main industrial application for NO removal is the NH3 selective catalytic reduction (NH3-SCR) technology, which is used to treat NO in flue gas. x Using NH3 as a reducing agent, NO is reduced by a catalyst. x It reacts with NH3 in the temperature range of 150–450℃ to undergo a disproportionation reaction, eventually converting into N2 and H2O. Vanadium-based catalysts, for example, exhibit excellent sulfur and water resistance in flue gas environments of 180–450℃, and are widely used in denitrification units in industries such as power generation, coking, and cement.

[0004] Currently available catalytic materials suitable for SCR include honeycomb and granular catalytic materials, with catalysts directly molded into shape. Catalytic material supports include flexible catalytic filter bags and rigid catalytic filter cartridges. Honeycomb catalytic materials are suitable for large-volume flue gas applications in power generation, coking, and sintering, while granular catalytic materials are suitable for diffusion beds and moving bed reactors. The catalytic material supports also function as denitrification and dust removal devices. Rigid catalytic filter cartridges are suitable for flue gas denitrification and dust removal in glass, cement, and biomass power generation, while flexible catalytic filter bags are suitable for low-sulfur flue gas from waste incineration, solid waste incineration, and lime kiln low-sulfur flue gas. Compared to catalytic filter bags, catalytic filter cartridges exhibit better mechanical strength and chemical stability over a wider temperature range. Furthermore, during flue gas purification using catalytic filter cartridges, dust and waste desulfurizing agents are removed through the dense dust-removing membrane on the outer layer of the cartridge, thus protecting the denitrification catalyst loaded inside the cartridge from poisoning by SO2 and harmful substances such as alkalis and alkaline earth metals.

[0005] For VOCs removal technologies, catalytic oxidation is considered a highly efficient method due to its high economic feasibility, low cost, and low generation of secondary pollutants. CN202110562186.X proposes a regionally coated VOC catalyst and its preparation method. The VOC catalyst of this invention includes a support and a coating applied to the support. The coating comprises a front coating and a back coating. The front coating is located at the inlet end of the catalyst and is loaded with noble metals Pt and Pd, and contains magnesium-aluminum composite oxide Mg-Al2O3 and cerium dioxide. The back coating is located at the outlet end of the catalyst and is loaded with noble metals Pt and Pd, and contains tungsten-aluminum composite oxide W-Al2O3 and hydrogen-form β-molecular sieves. This method can improve the conversion efficiency of the catalyst for VOCs pollutants with a relatively low noble metal loading.

[0006] Besides the VOCs catalysts used in the aforementioned inventions, classic vanadium-based denitration catalysts also possess the potential and feasibility for removing VOCs. For example, when VOCs are present in the atmosphere... x When W or Mo is added to a TiO2 catalyst, the formation and presence of NO promotes an increase in VOCs conversion. Under O2 conditions, NO in WO3... x and MoO x Oxidation to NO2 occurs, and NO2 further promotes the reaction of gaseous O2 in the VOC phase according to the MK reaction mechanism. x Surface re-oxidation improves VOC conversion. Furthermore, VW(Mo) / Ti catalysts are used for NO removal. x Its temperature range is similar to that for VOCs removal, allowing for the simultaneous removal of NO under complex operating conditions. x And VOCs offer possibilities.

[0007] Therefore, it can remove NO at the same timex Multifunctional catalytic filter cartridges for VOCs have emerged, addressing the purification needs of high-temperature, high-dust flue gas in small and medium-sized industrial equipment. In recent years, their unique characteristics have made them a promising integrated synergistic removal technology. The catalytic filter cartridge substrate is a cylindrical tube, manufactured through vacuum forming of ceramic fibers. The ceramic filter fibers mainly include aluminum silicate, calcium silicate, and mullite, resulting in filter cartridges with high mechanical strength and chemical stability. Existing catalytic filter cartridges primarily employ a V-Ti catalytic system, with an activity temperature range concentrated between 250 and 350°C and a denitrification rate greater than 90%. Furthermore, the presence of H2O in the catalytic filter cartridge significantly weakens the undesirable oxidation of NH3, thereby improving the selectivity of SCR, and it also provides significant resistance to SO2. However, when a V-based catalyst is required to catalyze the oxidation of VOCs, existing technologies still suffer from issues such as a high amount of byproducts and CO2 buildup. x The disadvantage is that the selection is not very high.

[0008] Therefore, it is still necessary to research and develop a method that can simultaneously remove NO. x A novel multifunctional catalytic filter element for VOCs and a method for manufacturing it. Summary of the Invention

[0009] In view of the problems existing in the prior art, the purpose of this invention is to provide a catalytic filter element, its preparation method, and its application. The catalytic filter element includes a filter element body, on the outer surface of which a denitrification catalyst is loaded with a loading depth extending into the filter element body; the inner surface of which a VOCs removal catalyst is loaded with a loading depth extending outward from the filter element body. The resulting catalytic filter element can simultaneously remove NO in complex flue gas, within the same catalytic reaction unit, and under the same temperature zone. x It meets the requirements for VOCs removal, achieving a removal rate of over 90% and exhibiting strong stability, enabling it to simultaneously remove NO for extended periods with high efficiency. x and VOCs.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a catalytic filter element, comprising a filter element body, wherein a denitrification catalyst is loaded on the outer surface of the filter element body, the denitrification catalyst having a loading depth into the interior of the filter element body; and a VOCs removal catalyst is loaded on the inner surface of the filter element body, the VOCs removal catalyst having a loading depth into the exterior of the filter element body.

[0012] This invention proposes a novel composite ceramic fiber catalytic filter element, using a ceramic fiber filter element as the matrix, with a denitrification catalyst externally dripped onto the outer surface and a VOCs removal catalyst internally sprayed onto the inner surface, and then dried at room temperature followed by high-temperature calcination. Part of the denitrification catalyst also possesses VOCs removal functionality; the addition of a VOCs removal catalyst further enhances the VOCs removal capacity and efficiency, thereby improving CO2 efficiency. x Selectivity. The resulting ceramic filter element can simultaneously remove NO in complex flue gas, within the same catalytic reaction unit, and under the same temperature range. x It meets the requirements for VOCs removal, achieving a removal rate of over 90% and exhibiting strong stability, enabling it to simultaneously remove NO for extended periods with high efficiency. x and VOCs.

[0013] It should be noted that, in practical applications, the outer surface of the filter element is prone to physical collisions, scratches, and other damage. Moreover, the denitrification catalyst load is often high while the VOCs removal catalyst load is relatively low. Furthermore, since the VOCs removal catalyst is more expensive, spraying the VOCs removal catalyst onto the inner wall is a way to protect the VOCs removal catalyst and ensure that the performance of the resulting ceramic fiber filter element can be stably maintained.

[0014] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0015] As a preferred embodiment of the present invention, the filter element body includes a ceramic fiber filter element.

[0016] Preferably, the wall thickness of the filter element body is 15-25mm, such as 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm or 25mm, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0017] Preferably, the loading depth of the denitrification catalyst is 20% to 90% of the thickness of the filter element body wall, such as 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0018] Preferably, the loading depth of the denitrification catalyst is 3 to 20 mm, such as 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm or 20 mm, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0019] Preferably, the sum of the loading depth of the denitrification catalyst and the loading depth of the VOCs catalyst is less than or equal to the wall thickness of the filter element body.

[0020] It should be noted that there may be an overlap between the inward loading depth of the denitrification catalyst and the outward loading depth of the VOCs catalyst. This overlap is unavoidable when the actual preparation process is not precise, but it does not significantly affect the catalytic performance of the filter element. Since both types of catalysts can actually exert a certain catalytic effect on their respective targets, stacking them would be a waste of catalysts. Therefore, using as little catalyst as possible to achieve the target effect while ensuring sufficient loading of both the denitrification catalyst and the VOCs catalyst is of practical significance for cost control.

[0021] Preferably, the denitrification catalyst comprises any one or a combination of at least two of oxides of V, W, Mo, and Zr. Typical but non-limiting examples of such combinations include combinations of V oxide and W oxide, V oxide and Mo oxide, V oxide and Zr oxide, W oxide and Mo oxide, W oxide and Zr oxide, or Mo oxide and Zr oxide.

[0022] Preferably, the VOCs removal catalyst includes MnO2 and CoO2. x Or any one or at least two combinations of Pt, typical but non-limiting examples of which include MnO2 and CoO x Combinations of MnO2 and Pt, or Pt and CoO x The combination of .

[0023] Preferably, the VOCs removal catalyst is in the form of nano-sized powder.

[0024] As a preferred embodiment of the present invention, the catalytic filter element further includes a catalyst carrier distributed in the filter element body.

[0025] The support is used to disperse the active components (denitrification catalyst and VOCs removal catalyst). Using only the active components would require a large quantity and be costly. The presence of the support is equivalent to achieving the same or similar catalytic effect with cheaper materials. Without pre-impregnation of the catalyst support, the loading rate of the active components will decrease, and the uniformity of dispersion will also decrease. Therefore, the presence of the catalyst support is preferable to ensure further enhancement of the catalytic effect.

[0026] Preferably, both the denitrification catalyst and the VOCs removal catalyst are supported on the catalyst support in the corresponding region.

[0027] Preferably, the catalyst support comprises any one or a combination of at least two of TiO2, Al2O3, or SiO2, and typical but non-limiting examples of such combinations include combinations of TiO2 and Al2O3, combinations of SiO2 and TiO2, or combinations of Al2O3 and SiO2.

[0028] Preferably, based on the mass of the catalytic filter element as 100 wt%, the loading of the catalyst carrier is 35 to 55 wt%, such as 35 wt%, 37 wt%, 39 wt%, 41 wt%, 43 wt%, 45 wt%, 47 wt%, 49 wt%, 51 wt%, 53 wt%, or 55 wt%, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0029] Preferably, based on the mass of the catalytic filter element as 100 wt%, the loading of the denitrification catalyst is 2–45 wt%, for example, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%. The values ​​are 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, 36wt%, 37wt%, 38wt%, 39wt%, 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, or 45wt%, etc., but are not limited to the listed values. Other unlisted values ​​within the above range also apply.

[0030] Preferably, based on the mass of the catalytic filter element as 100 wt%, the loading of the VOCs removal catalyst is 0.5 to 5 wt%, for example, 0.5 wt%, 0.8 wt%, 1.1 wt%, 1.4 wt%, 1.7 wt%, 2 wt%, 2.3 wt%, 2.6 wt%, 2.9 wt%, 3.2 wt%, 3.5 wt%, 3.8 wt%, 4.1 wt%, 4.4 wt%, 4.7 wt%, or 5 wt%, etc., but is not limited to the listed values; other unlisted values ​​within the above range are also applicable.

[0031] In a second aspect, the present invention provides a method for preparing the catalytic filter element described in the first aspect, comprising the following steps:

[0032] Prepare the filter element body, drop a solution or emulsion containing denitrification catalyst raw material onto the outer surface of the filter element body, after the first drying, spray a solution or emulsion containing VOCs removal catalyst onto the inner surface of the filter element body, after the second drying, and then calcine to obtain the catalytic filter element.

[0033] It should be noted that the first and second drying processes are used to fix the corresponding catalysts to prevent subsequent processes from affecting the already loaded catalysts. Specifically, since the amount of VOCs removal catalyst is small while the amount of denitrification catalyst is large, if the VOCs removal catalyst is sprayed directly without the first drying, the unfixed denitrification catalyst will drip under gravity, thus carrying away or washing away some of the sprayed VOCs removal catalyst and interfering with the uniformity of both the denitrification and VOCs removal catalysts. Therefore, after the application of the denitrification catalyst solution, the first drying is required before applying the VOCs removal catalyst solution or emulsion. Similarly, if the VOCs catalyst is sprayed first and then the denitrification catalyst is added dropwise, even if the VOCs catalyst has been dried, the large amount of additional dropwise addition of the denitrification catalyst solution will affect the loading and uniformity of the VOCs catalyst. Therefore, this invention preferably adds the denitrification catalyst dropwise first and then sprays the VOCs removal catalyst.

[0034] As a preferred technical solution of the present invention, the denitrification catalyst raw material includes any one or a combination of at least two of the metal salts of V, W, Mo, and Zr. Typical but non-limiting examples of the combination include combinations of V metal salt and W metal salt, combinations of V metal salt and Mo metal salt, combinations of V metal salt and Zr metal salt, combinations of W metal salt and Mo metal salt, combinations of W metal salt and Zr metal salt, or combinations of Mo metal salt and Zr metal salt.

[0035] Preferably, the VOCs removal catalyst includes MnO2 and CoO2. xOr any one or a combination of at least two of Pt nanopowders, typical but not limiting examples of such combinations include MnO2 nanopowder and CoO x Combinations of nanopowders, combinations of MnO2 nanopowder and Pt nanopowder, or combinations of Pt nanopowder and CoO x Combination of nanopowders.

[0036] Preferably, the solutions or emulsions containing the denitrification catalyst raw materials and the solutions or emulsions containing the VOCs removal catalyst are prepared using ammonia water with a mass concentration of 1 to 10 wt%, for example, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, or 10 wt%, etc., but are not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0037] Preferably, in the solution or emulsion containing the denitrification catalyst raw material, the mass concentration of the denitrification catalyst raw material is 20-50 wt%, such as 20 wt%, 23 wt%, 26 wt%, 29 wt%, 32 wt%, 35 wt%, 38 wt%, 41 wt%, 44 wt%, 47 wt%, or 50 wt%, but is not limited to the listed values; other unlisted values ​​within the above range are also applicable.

[0038] Preferably, in the solution or emulsion containing the VOCs removal catalyst, the mass concentration of the VOCs removal catalyst is 1 to 10 wt%, for example, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, or 10 wt%, but is not limited to the listed values; other unlisted values ​​within the above range are also applicable.

[0039] As a preferred embodiment of the present invention, the dripping rate is 0.1–0.5 mL / min. -1 ·cm -2 For example, 0.1 mL·min -1 ·cm -2 0.15 mL·min -1 ·cm -2 0.2 mL·min -1 ·cm -2 0.25 mL·min -1 ·cm-2 0.3 mL·min -1 ·cm -2 0.35 mL·min -1 ·cm -2 0.4 mL·min -1 ·cm -2 0.45 mL·min -1 ·cm -2 Or 0.5 mL·min -1 ·cm -2 This applies to, but is not limited to, the listed values; other unlisted values ​​within the above range also apply.

[0040] Preferably, the dripping time is 30 to 60 seconds, such as 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, or 60 seconds, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0041] It should be noted that the factors affecting the loading of the denitrification catalyst and the VOC removal catalyst in this invention are related to the concentration of the catalyst solution or emulsion, the dripping / spraying rate, and the dripping / spraying time. With a constant concentration and rate, the longer the time, the greater the loading, up to adsorption saturation. With a constant concentration and time, the faster the rate, the greater the loading. With a constant rate and time, the higher the concentration, the greater the loading. It should also be noted that the catalyst solution, emulsion, or slurry used in this invention actually contains most of its metal oxides, which are insoluble in water. However, the particle size needs to be minimized through methods such as ball milling to obtain a uniformly mixed suspension. Therefore, the above-mentioned mass concentrations are average concentrations. Long-term storage or standing can lead to sedimentation or precipitation, making the solution less uniform. In addition, the loading depth is actually more related to the amount of water in the liquid being dripped / sprayed. The filter element is a complex porous material formed by the extrusion of multiple interwoven fibers. When a certain concentration of catalyst slurry is dripped onto the surface of the filter element, most of the catalyst particles will be intercepted on the surface, forming a "filter cake" structure. Some of the catalyst and catalyst molecules will penetrate into the filter element along with the water, thus having a certain loading depth.

[0042] As a preferred technical solution of the present invention, the preparation method further includes loading the filter element body with a catalyst carrier before adding the solution or emulsion containing the denitrification catalyst raw material.

[0043] Preferably, the method for loading the catalyst carrier onto the filter element body includes:

[0044] The filter element body is immersed in a solution containing a catalyst carrier and then dried.

[0045] Alternatively, the catalyst support can be added separately to a solution or emulsion containing denitrification catalyst raw material and a solution or emulsion containing VOCs removal catalyst, mixed evenly, and then used.

[0046] Preferably, the catalyst support comprises any one or a combination of at least two of TiO2 powder, Al2O3 powder, or SiO2 powder. Typical but non-limiting examples of such combinations include combinations of TiO2 powder and Al2O3 powder, combinations of SiO2 powder and TiO2 powder, or combinations of Al2O3 powder and SiO2 powder.

[0047] Preferably, the solution containing the catalyst support is prepared using ammonia water with a mass concentration of 1 to 10 wt%, such as 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, or 10 wt%, but is not limited to the listed values; other unlisted values ​​within the above range are also applicable.

[0048] Preferably, in the solution containing the catalyst support, the mass concentration of the catalyst support is 50-80 wt%, such as 50 wt%, 52 wt%, 54 wt%, 56 wt%, 58 wt%, 60 wt%, 62 wt%, 64 wt%, 66 wt%, 68 wt%, 70 wt%, 72 wt%, 74 wt%, 76 wt%, 78 wt%, or 80 wt%, but is not limited to the listed values; other unlisted values ​​within the above range are also applicable.

[0049] Preferably, the immersion time is 0.5 to 1 minute, such as 0.5 min, 0.55 min, 0.6 min, 0.65 min, 0.7 min, 0.75 min, 0.8 min, 0.85 min, 0.9 min, 0.95 min, or 1 minute, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0050] Preferably, the first drying method includes draining the liquid in a ventilated area at room temperature until no liquid drips.

[0051] As a preferred technical solution of the present invention, the second drying includes heating drying, and the temperature of the second drying is 50 to 120°C, such as 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0052] Preferably, the second drying time is 6 to 12 hours, such as 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, 10.5 hours, 11 hours, 11.5 hours or 12 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0053] Preferably, the roasting temperature is 300-500℃, such as 300℃, 320℃, 340℃, 360℃, 380℃, 400℃, 420℃, 440℃, 460℃, 480℃ or 500℃, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0054] Preferably, the roasting time is 1 to 3 hours, such as 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, or 3 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0055] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0056] (1) Prepare a commercial blank ceramic fiber filter element with a filter element wall thickness of 20mm;

[0057] Prepare a solution containing any one or at least two of the catalyst support TiO2, Al2O3 or SiO2: Dissolve the powder of the corresponding industrial-grade catalyst support in 1-10 wt% ammonia water, and control the mass concentration of the catalyst support to be 50-80 wt%.

[0058] Prepare a solution or emulsion containing denitrification catalyst raw materials: Mix any one or at least two combinations of metal salts of V, W, Mo, and Zr with 1 to 10 wt% ammonia water until homogeneous, and control the mass concentration of the denitrification catalyst raw materials to be 20 to 50 wt%.

[0059] Prepare a solution or emulsion containing a VOCs removal catalyst: Add MnO2 and CoO2... xThe catalyst is mixed uniformly with 1-10 wt% ammonia water, and the mass concentration of the de-VOCs catalyst is 1-10 wt%.

[0060] (2) Immerse the ceramic fiber filter element in the solution containing the catalyst support for 0.5 to 1 minute, so that the loading of the catalyst support is 35 to 55 wt%. After immersion, drain the filter element in a ventilated place at room temperature until no liquid drips.

[0061] (3) Add the solution or emulsion containing the denitrification catalyst raw material to the outer surface of the drained filter element, controlling the dripping rate to be 0.1-0.5 mL / min. -1 ·cm -2 The catalyst is added dropwise for 30–60 seconds to achieve a loading of 2%–45% and a loading depth of 3–20 mm.

[0062] (4) After loading, the filter element is drained in a ventilated place at room temperature until no liquid drips. The solution or emulsion containing the VOCs removal catalyst is sprayed onto the inner surface of the drained filter element. The loading amount of the VOCs removal catalyst is controlled to be 0.5% to 5%, and the loading depth is less than or equal to 3 mm.

[0063] (5) After completing the above steps, the filter element is dried at 50-120℃ for 6-12 hours and then calcined at 300-500℃ for 1-3 hours to obtain the finished catalytic filter element.

[0064] Thirdly, the present invention provides an application of the catalytic filter element described in the first aspect or the catalytic filter element obtained by the preparation method described in the second aspect, the application including simultaneous removal of NO. x and VOCs.

[0065] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0066] This invention develops a novel composite ceramic fiber catalytic filter element. It uses a ceramic fiber filter element as the matrix, with a denitrification catalyst externally dripped onto the outer surface and a VOCs removal catalyst internally sprayed onto the inner surface. The filter element is then dried at room temperature and calcined at high temperature. Part of the denitrification catalyst also possesses VOCs removal functionality; the addition of a VOCs removal catalyst further enhances the VOCs removal capacity and efficiency, thereby improving CO2 efficiency. x Selectivity. The resulting ceramic filter element can simultaneously remove NO in complex flue gas, within the same catalytic reaction unit, and under the same temperature range. x It meets the requirements for VOCs removal, achieving a removal rate of over 90% and exhibiting strong stability, enabling it to simultaneously remove NO for extended periods with high efficiency. x and VOCs. Attached Figure Description

[0067] Figure 1 This is a schematic flowchart of the preparation method of the catalytic filter element in Example 1. Detailed Implementation

[0068] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0069] Example 1

[0070] This embodiment provides a method for preparing a catalytic filter element, such as... Figure 1 As shown, the preparation method includes the following steps:

[0071] (1) Prepare commercial blank ceramic fiber filter elements (blank filter element wall thickness 20mm);

[0072] Prepare a solution containing the catalyst support TiO2: Dissolve industrial TiO2 powder in 6 wt% ammonia water, and control the mass concentration of TiO2 to 65 wt%.

[0073] Prepare a solution or emulsion containing denitrification catalyst raw materials: Mix the metal salts of V and Mo (ammonium metavanadate, molybdic acid) with 5 wt% ammonia water until homogeneous, and control the mass concentration of the denitrification catalyst raw materials to be 35 wt%.

[0074] Prepare a solution or emulsion containing a VOCs removal catalyst: Mix Pt nanopowder with 6 wt% ammonia water until homogeneous, wherein the mass concentration of the VOCs removal catalyst is 6 wt%.

[0075] (2) Immerse the ceramic fiber filter element in the solution containing the catalyst support TiO2 for 1 minute, and drain the filter element in a ventilated place at room temperature until no liquid drips.

[0076] (3) Add the solution or emulsion containing the denitrification catalyst raw material to the outer surface of the drained filter element, controlling the dripping rate to be 0.4 mL / min. -1 ·cm -2 The catalyst was added dropwise for 45 seconds to achieve a loading of 15 wt% and a loading depth of 17 mm.

[0077] (4) After loading, the filter element is drained in a ventilated place at room temperature until no liquid drips. The solution or emulsion containing the VOCs removal catalyst is sprayed onto the inner surface of the drained filter element. The loading amount of the VOCs removal catalyst is controlled to be 2wt% and the loading depth is equal to 3mm.

[0078] (5) After completing the above steps, the filter element is dried at 80°C for 8 hours and then calcined at 350°C for 2 hours to obtain the finished catalytic filter element.

[0079] Example 2

[0080] This embodiment provides a method for preparing a catalytic filter element, the method comprising the following steps:

[0081] (1) Prepare commercial blank ceramic fiber filter elements (blank filter element wall thickness 20mm);

[0082] Prepare a solution containing catalyst support Al2O3: Dissolve industrial Al2O3 powder in 1 wt% ammonia water, and control the mass concentration of Al2O3 to be 50 wt%.

[0083] Prepare a solution or emulsion containing the denitrification catalyst raw material: Mix the metal salt of V (ammonium metavanadate) with 1 wt% ammonia water evenly, and control the mass concentration of the denitrification catalyst raw material to be 20 wt%.

[0084] Prepare a solution or emulsion containing a VOCs removal catalyst: Mix MnO2 nanopowder with 1 wt% ammonia water until homogeneous, wherein the mass concentration of the VOCs removal catalyst is 1 wt%.

[0085] (2) Immerse the ceramic fiber filter element in the solution containing the catalyst support TiO2 for 0.5 min, and drain the filter element in a ventilated place at room temperature until no liquid drips;

[0086] (3) Add the solution or emulsion containing the denitrification catalyst raw material to the outer surface of the drained filter element, controlling the dripping rate to be 0.2 mL / min. -1 ·cm -2 The catalyst was added dropwise for 30 seconds to achieve a loading of 5 wt% and a loading depth of 5 mm.

[0087] (4) After loading, the filter element is drained in a ventilated place at room temperature until no liquid drips. The solution or emulsion containing the VOCs removal catalyst is sprayed onto the inner surface of the drained filter element. The loading amount of the VOCs removal catalyst is controlled to be 0.5wt% and the loading depth is equal to 0mm, that is, the catalyst is only loaded on the inner surface.

[0088] (5) After completing the above steps, the filter element is dried at 50°C for 12 hours and then calcined at 300°C for 3 hours to obtain the finished catalytic filter element.

[0089] Example 3

[0090] This embodiment provides a method for preparing a catalytic filter element, the method comprising the following steps:

[0091] (1) Prepare commercial blank ceramic fiber filter elements (blank filter element wall thickness 20mm);

[0092] Prepare a solution containing the catalyst support SiO2: Dissolve industrial SiO2 powder in 10wt% ammonia water, and control the mass concentration of SiO2 to 80wt%.

[0093] Prepare a solution or emulsion containing denitrification catalyst raw materials: Mix metal salts of V, W, Mo and Zr (ammonium metavanadate, ammonium metatungstate, metamolybdic acid, zirconium nitrate) with 10 wt% ammonia water until homogeneous, and control the mass concentration of the denitrification catalyst raw materials to be 50 wt%.

[0094] Prepare a solution or emulsion containing a VOCs removal catalyst: Add CoO x The nanopowder was mixed evenly with 10 wt% ammonia water, and the mass concentration of the VOCs removal catalyst was 10 wt%.

[0095] (2) Immerse the ceramic fiber filter element in the solution containing the catalyst support TiO2 for 1 minute, and drain the filter element in a ventilated place at room temperature until no liquid drips.

[0096] (3) Add the solution or emulsion containing the denitrification catalyst raw material to the outer surface of the drained filter element, controlling the dripping rate to be 0.4 mL / min. -1 ·cm -2 The catalyst was added dropwise for 35 seconds to achieve a loading of 20 wt% and a loading depth of 10 mm.

[0097] (4) After loading, the filter element is drained in a ventilated place at room temperature until no liquid drips. The solution or emulsion containing the VOCs removal catalyst is sprayed onto the inner surface of the drained filter element. The loading amount of the VOCs removal catalyst is controlled to be 5wt% and the loading depth is about 2mm.

[0098] (5) After completing the above steps, the filter element is dried at 120°C for 6 hours and then calcined at 400°C for 1 hour to obtain the finished catalytic filter element.

[0099] Example 4

[0100] This embodiment provides a method for preparing a catalytic filter element. The preparation method does not load the blank filter element with a catalyst support. That is, in step (1) of the preparation method, a solution containing the catalyst support TiO2 is not prepared. Step (1) is not performed. Instead, in step (2), a solution or emulsion containing denitrification catalyst raw material is directly added to the blank filter element. Apart from this, the other conditions are exactly the same as in Example 1.

[0101] Example 5

[0102] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1, except that the mass concentration of the solution containing the catalyst support TiO2 in step (1) is adjusted from 65wt% to 40wt%.

[0103] Example 6

[0104] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1, except that the mass concentration of the solution containing the catalyst support TiO2 in step (1) is adjusted from 65wt% to 50wt%.

[0105] Example 7

[0106] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1, except that the mass concentration of the solution containing the catalyst support TiO2 in step (1) is adjusted from 65wt% to 80wt%.

[0107] Example 8

[0108] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1, except that the mass concentration of the solution containing the catalyst support TiO2 in step (1) is adjusted from 65wt% to 90wt%.

[0109] Example 9

[0110] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1 except that the loading of the denitrification catalyst is adjusted from 15wt% to 2wt% and the loading depth is adjusted from 17mm to 2mm by adjusting the mass concentration of the solution or emulsion containing the denitrification catalyst raw material in step (1), adjusting the dropping rate and dropping time of the solution or emulsion containing the denitrification catalyst raw material in step (3).

[0111] Example 10

[0112] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1 except that the loading of the denitrification catalyst is adjusted from 15wt% to 10wt% and the loading depth is adjusted from 17mm to 5mm by adjusting the mass concentration of the solution or emulsion containing the denitrification catalyst raw material in step (1), adjusting the dropping rate and dropping time of the solution or emulsion containing the denitrification catalyst raw material in step (3).

[0113] Example 11

[0114] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1 except that the loading of the denitrification catalyst is adjusted from 15wt% to 30wt% and the loading depth is adjusted from 17mm to 10mm by adjusting the mass concentration of the solution or emulsion containing the denitrification catalyst raw material in step (1), adjusting the dropping rate and dropping time of the solution or emulsion containing the denitrification catalyst raw material in step (3).

[0115] Example 12

[0116] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1 except that the loading of the denitrification catalyst is adjusted from 15wt% to 40wt% and the loading depth is adjusted from 17mm to 20mm by adjusting the mass concentration of the solution or emulsion containing the denitrification catalyst raw material in step (1), adjusting the dropping rate and dropping time of the solution or emulsion containing the denitrification catalyst raw material in step (3).

[0117] Example 13

[0118] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1 except that the mass concentration of the solution containing VOCs catalyst in step (1) is adjusted, the loading of VOCs catalyst in step (4) is adjusted from 2wt% to 0.1wt%, and the loading depth is adjusted from 3mm to 0mm, that is, loading is only carried out on the inner surface.

[0119] Example 14

[0120] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1 except that the mass concentration of the solution containing VOCs catalyst in step (1) is adjusted, the loading of VOCs catalyst in step (4) is adjusted from 2wt% to 3wt%, and the loading depth is adjusted from 3mm to 2mm.

[0121] Example 15

[0122] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as in Example 1 except that the mass concentration of the solution containing VOCs catalyst in step (1) is adjusted, the loading of VOCs catalyst in step (4) is adjusted from 2wt% to 6wt%, and the loading depth is adjusted from 3mm to 5mm.

[0123] Example 16

[0124] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as that in Example 1, except that the calcination temperature in step (5) is adjusted from 400°C to 270°C.

[0125] Example 17

[0126] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as that in Example 1, except that the calcination temperature in step (5) is adjusted from 400°C to 300°C.

[0127] Example 18

[0128] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as that in Example 1, except that the calcination temperature in step (5) is adjusted from 400°C to 500°C.

[0129] Example 19

[0130] This embodiment provides a method for preparing a catalytic filter element. The preparation method is exactly the same as that in Example 1, except that the calcination temperature in step (5) is adjusted from 400°C to 530°C.

[0131] Example 20

[0132] This embodiment provides a method for preparing a catalytic filter element. The preparation method swaps steps (3) and (4). That is, after step (1), the solution containing the VOCs removal catalyst is sprayed onto the inner surface of the drained filter element. After the filter element is drained in a ventilated place at room temperature until no liquid drips, the solution or emulsion containing the denitrification catalyst raw material is dripped onto the outer surface of the drained filter element. Except for the above, the other conditions are exactly the same as in Example 1.

[0133] Comparative Example 1

[0134] This comparative example provides a method for preparing a catalytic filter element. The preparation method does not involve loading a denitrification catalyst. That is, in step (1) of the preparation method, a solution or emulsion containing denitrification catalyst raw materials is not prepared, and step (3) is not performed. Apart from this, the other conditions are exactly the same as in Example 1.

[0135] Comparative Example 2

[0136] This comparative example provides a method for preparing a catalytic filter element. The preparation method does not involve loading a VOCs removal catalyst, that is, the preparation method does not prepare a solution containing a VOCs removal catalyst in step (1) and does not perform step (4). Apart from this, the other conditions are exactly the same as in Example 1.

[0137] Comparative Example 3

[0138] This comparative example provides a method for preparing a catalytic filter element. The preparation method does not involve loading a denitrification catalyst or a VOCs removal catalyst. That is, in step (1) of the preparation method, a solution or emulsion containing a denitrification catalyst raw material and a solution containing a VOCs removal catalyst are not prepared, and steps (3) and (4) are not performed. Apart from this, the other conditions are exactly the same as in Example 1.

[0139] Catalytic testing was conducted on the catalytic filter cartridges obtained in the examples and comparative examples. A fixed-bed quartz tube microreactor was used. Determination of NO removal in each sample x The catalytic activity of NO and VOCs was studied. The simulated flue gas consisted of 1000 ppm NH3, 850 ppm NO, 850 ppm toluene, 5 vol.% O2, 10 vol.% H2O, and 100 ppm SO2, and was balanced with N2 at a surface flow rate of 0.60 Nm / min. The flow rate of each gas in the simulated flue gas was precisely controlled by a mass flow meter. Before entering the reactor, the gases were mixed in a gas mixing tank, preheated, and then passed through a catalytic filter. The temperature range of the catalytic reaction unit was 250℃ to 450℃. An online portable FT-IR analyzer (Gasmet DX4000, Finland) was used to analyze the NO content in the flue gas. x The concentration of toluene is continuously monitored. Data is collected after each temperature point has stabilized for more than 30 minutes. The flue gas analyzer is pre-calibrated with standard gases for each required gas, enabling accurate online monitoring.

[0140] The formulas for calculating NO conversion rate, toluene conversion rate, and surface velocity are as follows:

[0141]

[0142]

[0143]

[0144] Among them, [NO] in and [NO] out These represent the NO concentrations in the inlet and outlet gases, respectively. [Toluene] in and [Toluene] out These represent the concentrations of toluene in the inlet and outlet gases, respectively. Surface velocity is the flow rate of flue gas through each filtration zone per unit time. V(m 3 / min) is the volume of flue gas passing through per minute, S(m 2 ) represents the area of ​​the filtration region of the catalytic filter element.

[0145] The results are recorded in Table 1.

[0146] Table 1

[0147]

[0148]

[0149]

[0150]

[0151] The data above shows that:

[0152] (1) Overview of Examples 1-3: Example 1 has the best effect. The catalytic performance of Examples 2 and 3 is slightly reduced compared with Example 1. The reason is that the loading of denitrification catalyst and VOCs removal is reduced in Example 2. In Example 3, the catalyst content is increased. After exceeding a certain amount (optimal value), too much catalyst adheres to the surface of the filter fiber, resulting in a reduction in the pore size and pore volume between catalyst particles, thereby reducing the catalytic effect.

[0153] (2) Comparison of Example 1 and Comparative Examples 1-3: The filter cartridge simultaneously loaded with denitrification and VOCs removal catalysts (Example 1) showed the best performance. The filter cartridge without VOCs removal catalyst loading (Comparative Example 2) still achieved good denitrification and VOCs removal effects, but not as good as the filter cartridge loaded with both catalysts simultaneously. The denitrification and VOCs removal efficiency was significantly reduced in the filter cartridge without denitrification catalyst loading (Comparative Example 1). The filter cartridge without either catalyst loading (Comparative Example 3) had very low denitrification and VOCs removal effects, with an efficiency not exceeding 20%.

[0154] (3) Comparison between Example 1 and Examples 4-8: Without the addition of TiO2 (Example 4), the denitrification and VOCs removal efficiency decreased significantly, while the addition of TiO2 of different mass concentrations (Examples 5-8) had no significant effect on denitrification and VOCs removal.

[0155] (4) Comparison between Example 1 and Examples 9-12: The loading of the denitrification catalyst has a significant impact on the denitrification and VOCs removal effects. Too low a loading (Examples 9 and 10) will significantly reduce the catalytic effect of the catalyst; too high a loading (Examples 11 and 12) will also reduce the catalytic effect to a certain extent, the reasons for which are stated in (1); a suitable loading can achieve a better catalytic effect, and Example 1 has the best effect.

[0156] (5) Comparison of Example 1 with Examples 13-15: The loading of the VOCs removal catalyst has a certain impact on the denitrification and VOCs removal effects. When the loading of the VOCs removal catalyst is too low (Example 13), the denitrification and VOCs removal efficiency decreases. However, when the loading of the VOCs removal catalyst is higher than the suitable value (Examples 14-15), the denitrification and VOCs removal effects do not increase significantly. Adhering to the principle of economic applicability, the optimal value can be adopted.

[0157] Example 1 showed the best results.

[0158] (6) Comparison of Example 1 with Examples 16-19: Calcination temperature has a significant impact on denitrification and VOCs removal efficiency, with 350℃ showing the best effect (Example 1). At 400℃ (Example 17), the effect is not significantly different from 350℃; therefore, 350℃ is preferable for cost savings. Denitrification and VOCs removal efficiencies decrease to some extent at 250℃ (Example 16) and 450℃ (Example 18), with a more pronounced decrease at 250℃. At 500℃ (Example 19), the denitrification catalyst sinters and deactivates, resulting in a significant decrease in denitrification efficiency. However, due to the high temperature resistance and difficulty in sintering of the VOCs removal catalyst, it still maintains a good VOCs removal effect.

[0159] (7) Comparison between Example 1 and Example 20: The coating order of the denitration catalyst and the VOCs removal catalyst has no significant effect on its efficiency. The effect of coating the denitration catalyst first and then the VOCs removal catalyst is slightly better than coating the VOCs removal catalyst first and then the denitration catalyst.

[0160] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0161] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0162] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0163] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a catalytic filter element, characterized in that, Includes the following steps: Prepare the filter element body, drop a solution or emulsion containing denitrification catalyst raw material onto the outer surface of the filter element body, after the first drying, spray a solution or emulsion containing VOCs removal catalyst onto the inner surface of the filter element body, after the second drying, calcinate to obtain the catalytic filter element; In the solution or emulsion containing the denitrification catalyst feedstock, the mass concentration of the denitrification catalyst feedstock is 20-50 wt%. In the solution or emulsion containing the VOCs removal catalyst, the mass concentration of the VOCs removal catalyst is 1~10 wt%; The dropping rate is 0.1~0.5 mL / min. -1 ·cm -2 ; The dripping time is 30-60 seconds; The first drying method includes draining the liquid in a ventilated area at room temperature until no liquid drips; The second drying includes heat drying, and the temperature of the second drying is 50~120℃; The preparation method further includes: Before adding a solution or emulsion containing a denitrification catalyst raw material, the filter element body is loaded with a catalyst carrier; Alternatively, the catalyst support can be added separately to a solution or emulsion containing a denitrification catalyst feedstock and a solution or emulsion containing a VOCs removal catalyst, mixed thoroughly, and then used. The catalytic filter element prepared by the method includes a filter element body, on the outer surface of the filter element body a denitrification catalyst is loaded, the denitrification catalyst having a loading depth into the filter element body; on the inner surface of the filter element body a VOCs removal catalyst is loaded, the VOCs removal catalyst having a loading depth into the outside of the filter element body. Based on a catalytic filter element mass of 100 wt%, the loading of the denitrification catalyst is 2-45 wt%. Based on a catalytic filter element mass of 100 wt%, the loading of the VOCs removal catalyst is 0.5~5 wt%. The wall thickness of the filter element body is 15~25mm; The loading depth of the denitrification catalyst is 20% to 90% of the wall thickness of the filter element body; The sum of the loading depth of the denitrification catalyst and the loading depth of the VOCs catalyst is less than or equal to the wall thickness of the filter element body; The catalytic filter element also includes a catalyst support distributed in the filter element body; Both the denitrification catalyst and the VOCs removal catalyst are supported on the catalyst support in the corresponding region; Based on the mass of the catalytic filter element being 100 wt%, the loading of the catalyst support is 35~55 wt%.

2. The preparation method according to claim 1, characterized in that, The filter element body includes a ceramic fiber filter element.

3. The preparation method according to claim 1, characterized in that, The loading depth of the denitrification catalyst is 3~20mm.

4. The preparation method according to claim 1, characterized in that, The denitrification catalyst comprises any one or a combination of at least two of the oxides of V, W, Mo, and Zr.

5. The preparation method according to claim 1, characterized in that, The VOCs removal catalyst includes MnO2 and CoO2. x Or any one or at least a combination of two of Pt.

6. The preparation method according to claim 1, characterized in that, The VOCs removal catalyst is in the form of nano-sized powder.

7. The preparation method according to claim 1, characterized in that, The catalyst support includes any one or a combination of at least two of TiO2, Al2O3, or SiO2.

8. The preparation method according to claim 1, characterized in that, The raw materials for the denitrification catalyst include any one or a combination of at least two of the metal salts of V, W, Mo, and Zr.

9. The preparation method according to claim 1, characterized in that, The VOCs removal catalyst includes MnO2 and CoO2. x Or any one or a combination of at least two of Pt nanopowders.

10. The preparation method according to claim 1, characterized in that, The solutions or emulsions containing the denitrification catalyst raw materials and the solutions or emulsions containing the VOCs removal catalyst were prepared using ammonia water with a mass concentration of 1~10wt%.

11. The preparation method according to claim 1, characterized in that, The method for loading the catalyst carrier onto the filter element body includes immersing the filter element body in a solution containing the catalyst carrier and performing a first drying.

12. The preparation method according to claim 1, characterized in that, The catalyst support includes any one or a combination of at least two of TiO2 powder, Al2O3 powder, or SiO2 powder.

13. The preparation method according to claim 11, characterized in that, The solution containing the catalyst support was prepared using ammonia water with a mass concentration of 1-10 wt%.

14. The preparation method according to claim 11, characterized in that, In the solution containing the catalyst support, the mass concentration of the catalyst support is 50-80 wt%.

15. The preparation method according to claim 11, characterized in that, The immersion time is 0.5 to 1 minute.

16. The preparation method according to claim 1, characterized in that, The second drying time is 6~12 hours.

17. The preparation method according to claim 1, characterized in that, The roasting temperature is 300~500℃.

18. The preparation method according to claim 1, characterized in that, The roasting time is 1 to 3 hours.

19. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) Prepare commercial blank ceramic fiber filter elements with a filter element wall thickness of 20mm; Prepare a solution containing any one or at least two of the catalyst supports TiO2, Al2O3, or SiO2: Dissolve the corresponding industrial-grade catalyst support powder in 1-10 wt% ammonia water, controlling the mass concentration of the catalyst support to be 50-80 wt%. Prepare a solution or emulsion containing the denitrification catalyst feedstock: Mix any one or at least two of the metal salts of V, W, Mo, and Zr with 1-10 wt% ammonia solution until homogeneous, controlling the mass concentration of the denitrification catalyst feedstock to be 20-50 wt%. Prepare a solution or emulsion containing a VOCs removal catalyst: Add MnO2 and CoO2... x The catalyst is prepared by uniformly mixing any one or at least two of the nanoparticles of Pt with 1-10 wt% ammonia water, wherein the mass concentration of the VOCs removal catalyst is 1-10 wt%. (2) Immerse the ceramic fiber filter element in the solution containing the catalyst carrier for 0.5 to 1 min, so that the loading of the catalyst carrier is 35 to 55 wt%. After immersion, drain the filter element in a ventilated place at room temperature until no liquid drips. (3) Add the solution or emulsion containing the denitrification catalyst raw material to the outer surface of the drained filter element, controlling the dripping rate to be 0.1~0.5 mL·min. -1 ·cm -2 The catalyst is added dropwise for 30-60 seconds to achieve a loading of 2-45 wt% and a loading depth of 3-20 mm. (4) After loading, the filter element is drained in a ventilated place at room temperature until no liquid drips. The solution or emulsion containing the VOCs removal catalyst is sprayed onto the inner surface of the drained filter element. The loading amount of the VOCs removal catalyst is controlled to be 0.5~5wt%, and the loading depth is less than or equal to 3mm. (5) After completing the above steps, the filter element is dried at 50~120℃ for 6~12h and then calcined at 300~500℃ for 1~3h to obtain the finished catalytic filter element.

20. The application of a catalytic filter element obtained by the preparation method according to any one of claims 1-19, characterized in that, The application includes simultaneous removal of NO. x and VOCs.

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