A high-precision filter element, a preparation method and a dust removal device comprising the filter element

Abstract

The present invention provides a high-precision filter element, a preparation method and a dust removal device comprising the filter element. The preparation method of the high-precision filter element comprises the following steps: S1: preparing SiO 2 Nanofiber membrane; S2: preparation of cross-linking agent; S3: SiO 2 The nanofiber membrane, glass fiber, protein and cross-linking agent are evenly dispersed and placed in a mold for drying to obtain the high-precision filter element; wherein the cross-linking agent is obtained by reacting sodium hyaluronate and chlorosilane. The filter element has high strength, high filtration efficiency, high temperature resistance and good water resistance, and is suitable for use in high-temperature and high-water content flue gas dust removal systems, which can reduce the frequency of equipment cleaning, reduce the energy consumption of the device, and ensure long-term and high-load operation of the device.

Description

Technical Field

[0001] The invention relates to the technical field of olefin preparation or oil decomposition in the petrochemical industry, and in particular to a high-precision filter element, a preparation method and a dust removal device comprising the filter element. Background Art

[0002] During the operation of certain petrochemical and chemical equipment, fine particles will be entrained in the high-temperature gas exceeding 500°C. The main components of the escaping fine particles are catalyst products, and the particle size distribution is usually: 0-5μm accounts for 70%; 5-20μm accounts for 25%; 20-40μm accounts for 5%; the median diameter of the particles is generally less than 5μm. At present, most of the particles are usually captured by multi-stage cyclone separators before exhaust gas is discharged, and the exhaust concentration is about 50-500mg / Nm 3 , about 70% of the dust particles discharged are 0-2μm in diameter. In this case, the dust in the gas needs to be further removed before the tail gas can be discharged into the atmosphere, or the impact on downstream devices can be reduced. This is undoubtedly a huge challenge for existing technologies.

[0003] Take the methanol to olefins (MTO) unit as an example. It is a unit that uses methanol as raw material and produces low-carbon olefins (ethylene and propylene) as target products. MTO includes reaction technology and separation technology. For the separation of target products, after the catalyst is separated from the reaction gas, the product gas is compressed, washed with alkali and water, and dried, and then a series of different carbon number components, such as C1 and C4+ components, are cut, and ethane and propane are removed, and finally ethylene and propylene products are separated.

[0004] During the operation of the MTO device, the reaction gas or exhaust gas with a high temperature of more than 500°C will carry about 500-1000 mg / Nm 3 The fine particles that escape are mainly composed of catalyst products. The gas contains more than 70% water. In this case, the catalyst needs to be further recovered before the gas can be discharged to the atmosphere or downstream purification and separation devices. Based on the above background, the petrochemical industry urgently needs a filter element that is resistant to high temperature, corrosion, water, and high filtration efficiency to collect fine particles in high-temperature exhaust gas, ensure that emissions meet standards at all times, or reduce the cleaning frequency of downstream devices.

[0005] Commonly used fine particle collection process solutions include ceramic filter element filters, metal filter element filters, bag filters, electrostatic precipitators and cyclone separators, but these technical solutions are not suitable for treating high-temperature exhaust gas from MTO and other devices. The main reasons are: 1. The particle size, specific gravity and resistivity parameters of fine particles are beyond the applicable range of electrostatic precipitators; 2. The material of bag filters can hardly withstand temperatures above 250°C; 3. The collection efficiency of cyclone separators cannot meet emission indicators; 4. Metal filter elements are not accurate and are not corrosion-resistant; 5. Ceramic filter elements are not water-resistant, have low strength and are easy to break. Summary of the invention

[0006] Purpose of the invention: The purpose of the present invention is to provide a high-precision filter element, a preparation method and a dust removal device containing the filter element, which can improve the precision, flow rate and strength of the filter element, and at the same time, combined with the dust removal device, can ensure the long-term online operation of the filter element. Thereby reducing the frequency of cleaning of downstream equipment, reducing the energy consumption of the device, and ensuring the long-term and high-load operation of the entire device.

[0007] The technical solution of the present invention:

[0008] In a first aspect, the present invention provides a method for preparing a high-precision filter element, comprising the following steps:

[0009] S1: Preparation of SiO2 nanofiber membrane;

[0010] S2: preparing a cross-linking agent;

[0011] S3: mixing and dispersing the SiO2 nanofiber membrane, glass fiber, protein and cross-linking agent uniformly, placing them in a mold and drying them to obtain the high-precision filter element;

[0012] Wherein, the cross-linking agent is obtained by reacting sodium hyaluronate and chlorosilane.

[0013] In some embodiments, S1 specifically includes: stirring tetraethyl orthosilicate in an acidic solution, adding PVA solution and stirring evenly to obtain a spinning solution; and performing electrostatic spinning to obtain a SiO2 nanofiber membrane.

[0014] In some embodiments, the preparation method of the cross-linking agent includes adding sodium hyaluronate to a solvent, then adding chlorosilane dropwise to the solution, heating under reflux for reaction, and obtaining the cross-linking agent.

[0015] In some embodiments, the chlorine-containing silane is selected from one or more combinations of 3-chloropropyltriethoxysilane, [2-[(chloromethyl)phenyl]ethyl]triethoxysilane, 1-trimethylsilyl-2-(p-chloromethyl)phenylethane, and 1-trimethylsilyl-2-(o-chloromethyl)phenylethane; optionally, the chlorine-containing silane is selected from one or more combinations of 1-trimethylsilyl-2-(p-chloromethyl)phenylethane and 1-trimethylsilyl-2-(o-chloromethyl)phenylethane.

[0016] The structural formulas of 1-trimethylsilyl-2-(p-chloromethyl)phenylethane and 1-trimethylsilyl-2-(o-chloromethyl)phenylethane contain not only chloride ions and silicon-oxygen bonds, but also benzene rings compared to 3-chloropropyltriethoxysilane. The structure of the prepared cross-linking agent is more stable, so that the obtained filter element has stronger high temperature resistance and stability.

[0017] In some embodiments, the heating temperature of the reflux is 80-120° C., and the reflux time is 5-15 h.

[0018] In some embodiments, the glass fiber is a nano glass fiber having a fiber length of 3-5 mm and a diameter of 10-15 um; for example, the diameter of the glass fiber may be one or more combinations of 10 um, 11 um, 12 um, 13 um, 14 um or 100 um; further, the diameter of the glass fiber is one or more combinations of 11 um, 12 um or 13 um.

[0019] In some embodiments, the protein is selected from one or more of natural proteins, artificially synthesized proteins and their derivatives; the function of the protein is to form a porous structure by volatilizing the protein through heating and drying during the preparation of the filter element.

[0020] In some embodiments, the mass ratio of the SiO2 nanofiber membrane, glass fiber, protein and cross-linking agent is 50-70:50-70:10-20:5-10; optionally, the mass ratio of the SiO2 nanofiber membrane, glass fiber and cross-linking agent is 68:15:8.

[0021] In a second aspect, the present application also provides a high-precision filter element prepared by the above-mentioned preparation method.

[0022] In a third aspect, the present application also provides a dust removal device that can be used for high-temperature flue gas, wherein the dust removal device is provided with a filtering structure, and the filtering structure is provided with the above-mentioned high-precision filter element.

[0023] In some embodiments, the dust removal device is also provided with a distribution and back-blowing structure; the reaction gas is first evenly distributed through the distribution structure, and then dust is removed through the filter element, and then online cleaning and regeneration is performed through the back-blowing structure; the above-mentioned dust removal device can reduce the catalyst content in the gas, thereby reducing the catalyst content in the subsequent water system, reducing the wear and blockage of the catalyst on the machine pump, pipeline, cold exchange equipment, and tower equipment, improving the heat exchanger effect, extending the operation cycle of the heat exchange equipment, reducing the cleaning frequency of the cold exchange equipment, reducing the energy consumption of the device, and ensuring the long-term and high-load operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A three-dimensional exploded view of a high-temperature dust removal device that can be used in petrochemical and chemical plants provided by the present invention;

[0025] Figure 2 An exploded view of a protective housing of a high-temperature dust removal device that can be used in petrochemical and chemical plants provided by the present invention;

[0026] Figure 3 An exploded view of an air blowing pipe of a high-temperature dust removal device that can be used in petrochemical and chemical plants provided by the present invention;

[0027] Figure 4 This is an exploded view of a conical ash discharge pipe of a high-temperature dust removal device that can be used in petrochemical and chemical plants provided by the present invention.

[0028] In the figure: 1. Protective shell; 2. Conical ash discharge pipe; 3. Filter inlet inspection port; 4. Pressure gauge; 5. Filter outlet; 6. Air inlet pipe; 7. Air blowing pipe; 8. Air storage tank; 9. Ash discharge closure cover; 10. Support ring frame; 11. High-precision filter element; 12. Ash collection port of riser; 13. Ash collection distribution port; 14. Connecting block; 15. Access pipe; 16. Ventilation pipe; 17. Air distribution pipe; 18. Air blowing nozzle; 19. Ash discharge port; 20. Threaded strip.

[0029] Beneficial effects:

[0030] 1. The present invention provides a high-precision filter element, which makes the dust content of the gas after filtration less than 10 mg, avoids fine particles from clogging the filter element, and has high strength, high filtration efficiency, high temperature resistance and good water resistance. It is suitable for use in dust removal systems of high-temperature and high-water content devices, can reduce the frequency of equipment cleaning, reduce the energy consumption of the device, and ensure long-term and high-load operation of the device.

[0031] 2. The present invention provides a dust removal device that can be used for high-temperature flue gas, which not only includes the above-mentioned filter element, but also is provided with a high-temperature dust removal device; the high-temperature dust removal device can intercept the catalyst dust in the high-temperature flue gas, thereby effectively reducing the catalyst content in the subsequent device and effectively improving the service life of the entire device. DETAILED DESCRIPTION

[0032] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0033] Unless otherwise specified, the chemical reagents used in the present invention are all commercially available analytically pure.

[0034] The sodium hyaluronate used in the present invention was purchased from Jinan Luxin Chemical Technology Co., Ltd.; 1-trimethylsilyl-2-(p-chloromethyl)phenylethane and 1-trimethylsilyl-2-(o-chloromethyl)phenylethane were purchased from Beijing Bailingwei Technology Co., Ltd.; [2-[(chloromethyl)phenyl]ethyl]triethoxysilane was purchased from Shaanxi Didu New Materials Co., Ltd.; 3-chloropropyltriethoxysilane was purchased from Hubei Xingyan New Materials Technology Co., Ltd.; glass fiber was purchased from Taian Haosong Fiber Co., Ltd., with a specification of 3-4.5 mm.

[0035] Preparation of SiO2 nanofiber membrane

[0036] H3PO4, methyl orthosilicate and water were mixed in a molar ratio of 0.01:2:10 and stirred thoroughly to prepare silica sol, and 10 wt% PVA solution was added to the sol and stirred evenly to obtain spinning solution. The spinning solution was prepared by mixing the mixture at a voltage of 15 kV and a perfusion rate of 1 mL h -1 Electrospinning was performed, and then the fiber membrane obtained by spinning was placed in a muffle furnace and calcined at 800° C. in an air atmosphere to obtain a SiO2 nanofiber membrane.

[0037] Cut the SiO2 nanofiber membrane into pieces for later use.

[0038] Preparation of crosslinker 1

[0039] 1 mol of sodium hyaluronate was added to 500 mL of DMF and stirred to disperse evenly. Then, 1.5 mol of 1-trimethylsilyl-2-(p-chloromethyl)phenylethane was added dropwise to the solution and heated under reflux at 80° C. for 10 h. After the reaction was completed, the solvent and the remaining solution were removed to obtain a crosslinker 1.

[0040] The structure of the crosslinker 1 is shown in Formula 1. The obtained product was analyzed by LC-MS, and the m / z of the product was 619.23 (100.0%), 620.31 (36.9%), 621.28 (10.4%), and 622.28 (2.0%), confirming that the structure shown in Formula 1 was successfully obtained.

[0041]

[0042] Preparation of crosslinker 2

[0043] The preparation method of crosslinker 2 is similar to that of crosslinker 1, except that 1-trimethylsilyl-2-(o-chloromethyl)phenylethane is used instead of 1-trimethylsilyl-2-(p-chloromethyl)phenylethane to prepare crosslinker 2.

[0044] The structure of cross-linking agent 2 is shown in Formula 2.

[0045]

[0046] Preparation of crosslinker 3

[0047] The preparation method of crosslinker 3 refers to that of crosslinker 1, except that [2-[(chloromethyl)phenyl]ethyl]triethoxysilane is used instead of 1-trimethylsilyl-2-(p-chloromethyl)phenylethane to prepare crosslinker 3.

[0048] The structure of crosslinker 3 is shown in Formula 3. The obtained product was analyzed by LC-MS, and the m / z of the product was 661.28 (100.0%), 662.35 (40.2%), 663.33 (11.7%), and 664.33 (2.4%), confirming that the structure shown in Formula 3 was successfully obtained.

[0049]

[0050] Preparation of crosslinker 4

[0051] The preparation method of crosslinker 4 is similar to that of crosslinker 1, except that 3-chloropropyltriethoxysilane is used instead of 1-trimethylsilyl-2-(p-chloromethyl)phenylethane to prepare crosslinker 4.

[0052] The structure of crosslinker 4 is shown in Formula 4. The obtained product was analyzed by LC-MS, and the m / z of the product was 585.25 (100.0%), 586.33 (33.7%), 587.29 (9.3%), and 588.30 (1.7%), confirming that the structure shown in Formula 4 was successfully obtained.

[0053]

[0054] Examples 1-6 and Comparative Examples 1-3

[0055] The cross-linking agent was added into a water / ethanol mixed solvent (volume ratio 6:4) and stirred evenly, and oxalic acid was added into the solvent and stirred rapidly to obtain a uniform solution.

[0056] Then, SiO2 nanofiber membrane, crosslinking agent, protein and glass fiber were added to the above uniform solution, and the solution was dispersed at a high speed of 12000 rpm for 15 minutes to uniformly disperse the solution to obtain a homogeneous dispersion. The dispersion was poured into a mold and dried to form. Finally, the dried product was transferred to a dryer and dried at 120°C for 24 hours to obtain the filter element.

[0057] The fractions of raw materials added in the examples and comparative examples are shown in Table 1.

[0058] Table 1 Formula table of embodiments and comparative examples (unit: part)

[0059]

[0060] Among them, crosslinking agent 5 refers to 1-trimethylsilyl-2-(p-chloromethyl)phenylethane; "S" represents an example, such as "S1" represents Example 1; "D" represents a comparative example, such as "D1" represents Comparative Example 1.

[0061] Performance Testing:

[0062] The filter elements obtained in the above embodiments and comparative examples were tested as follows:

[0063] Experiment 1: The filtration effect of the prepared protective material samples was tested using the "TSI-8130 Automated Filter Testers" instrument produced by TSI, USA. According to the "TSI 8130" test standard, an 8V needle-type electret sample was used to test the performance, and sodium chloride aerosol was used to test the filtration efficiency of the finished product of silica aerogel-modified melt-blown polypropylene material (50°C, humidity 80%).

[0064] Experiment 2: After the prepared aerogel sample is fully dried, the sample single wire is extracted and subjected to tensile test of the material matrix on an electronic universal tensile testing machine (LLY-06, China). In this test, the sample length between the single wire tensile clamps is 10 mm, and the sample tensile rate is 20 mm / min.

[0065] Experiment 3: GB / T 17911-2006 was used to test the density of the filter element.

[0066] Experiment 4: Gradually raise the ambient temperature of the filter element to 600°C and keep it warm for 20 minutes. After cooling to room temperature, test the filtration efficiency again.

[0067] Experiment 5: Immerse the filter element of the same size completely in deionized water at room temperature for 4 hours, take it out and dry it, test the change in the weight of the diaphragm before and after drying, and calculate the weight loss rate of the filter element in water according to the following formula: Weight loss rate (%) = (weight before immersion - weight after immersion) / weight before immersion. Repeat the above steps three times, and use the average of the three times to characterize the water resistance of the diaphragm. The larger the value, the worse the water resistance.

[0068] The above test results are shown in Table 2.

[0069] Table 2 Test results

[0070]

[0071] By comparing the above embodiments and comparative examples, it is found that when the cross-linking agent is the cross-linking agent 1-4 provided in the present application, it can work together with the SiO2 nanofiber membrane and glass fiber to improve the filtration efficiency and heat resistance of the filter element material. The experimental data of the filter element obtained by comparative examples 1-3 are significantly inferior to those of the embodiments.

[0072] By comparing Example 2, Example 4, Example 5 and Example 6, it is found that the raw materials used are 1-trimethylsilyl-2-(p-chloromethyl)phenylethane, 1-trimethylsilyl-2-(o-chloromethyl)phenylethane, [2-[(chloromethyl)phenyl]ethyl]triethoxysilane and 3-chloropropyltriethoxysilane, respectively. It can be seen that the filter element materials prepared using different raw materials are also slightly different. This may be because the structural formulas of 1-trimethylsilyl-2-(p-chloromethyl)phenylethane and 1-trimethylsilyl-2-(o-chloromethyl)phenylethane contain not only chloride ions and silicon-oxygen bonds, but also benzene rings compared to 3-chloropropyltriethoxysilane. The structure of the cross-linking agent prepared is more stable, so that the obtained filter element has stronger high temperature resistance and stability. Moreover, compared with [2-[(chloromethyl)phenyl]ethyl]triethoxysilane, 1-trimethylsilyl-2-(p-chloromethyl)phenylethane and 1-trimethylsilyl-2-(o-chloromethyl)phenylethane have better synergistic properties with glass fiber and SiO2 nanofiber membrane, which greatly enhances the elastic modulus and filtration efficiency of the filter element material.

[0073] Example 7

[0074] This embodiment provides a dust removal device that can be used in the petrochemical and chemical industries, and is equipped with the above-mentioned high-precision filter element.

[0075] The dust removal device includes a protective shell 1, which is used to protect the internal filter components to ensure that the device can operate normally without being affected by external forces. A conical ash discharge pipe 2 is arranged at the bottom of the protective shell 1, and the conical ash discharge pipe 2 is used to guide the dust generated after the gas is filtered inside the device to be discharged, ensuring that the filtered dust can be discharged in an orderly manner. A filter inspection port 3 is arranged on the top surface of the protective shell 1, and the filter inspection port 3 is used to inspect the device from time to time. A pressure gauge 4 is arranged on one side of the protective shell 1, and the pressure gauge 4 is used to monitor the pressure inside the device in real time to ensure that the pressure inside the device is in a normal state. A filter outlet 5 is arranged on one side of the protective shell 1, and the filter outlet 5 is used to discharge the filtered gas inside the device to ensure that the filtered gas can be processed in the next step in conjunction with other devices. An air inlet pipe 6 is arranged on one side of the protective shell 1, and the air inlet pipe 6 is used to guide the gas to enter the device for filtering. An air blowing pipe 7 is arranged on one side of the protective shell 1, and the air blowing pipe 7 is used to guide the backblowing gas to enter the components inside the protective shell 1. , to ensure that the dust attached to the high-precision filter element 11 can be blown off, a gas storage tank 8 is arranged on one side of the protective shell 1, and the gas storage tank 8 is used to store gas and provide back-blowing gas for the blowing assembly inside the protective shell 1. A ash discharge closing cover 9 is arranged below the conical ash discharge pipe 2, and the ash discharge closing cover 9 is used to close the conical ash discharge pipe 2 to ensure that the device is in a closed state during operation, and at the same time, it is convenient for the staff to collect dust. A support ring frame 10 is arranged inside the protective shell 1, and the support ring frame 10 is used to support and fix the position of the high-precision filter element 11 to ensure that the blowing nozzle 18 can be aligned with the top of the high-precision filter element 11. The high-precision filter element 11 as described above is arranged on one side of the support ring frame 10. The high-precision filter element 11 is used to filter the gas to ensure that the gas can be effectively filtered. An ash collecting port 12 is arranged at the bottom of the riser connected to the air inlet pipe 6. The ash collecting port 12 is used to guide the solid catalyst in the gas inside the protective shell 1 to directly fall to the bottom of the conical ash discharge pipe 2 through the ash collecting port 12, so that the staff can collect dust conveniently. A distribution port 13 is provided at the top of the riser, which cooperates with the air inlet pipe 6 to guide the gas into the support ring frame inside the protective shell 1, so that the incoming gas flows downward in the same direction as the falling direction of the catalytic dust, accelerating the catalyst dust to fall into the cone bucket and avoiding secondary dust.

[0076] A connecting block 14 is provided at one end of the air blowing pipe 7, and the connecting block 14 is used to connect the air blowing pipe 7 and the access pipe 15 to ensure that the gas entering the air blowing pipe 7 can enter the inside of the air distribution pipe 17. An access pipe 15 is provided below the connecting block 14, and the access pipe 15 is used to connect the air distribution pipe 17 to ensure that the gas entering the air blowing pipe 7 can enter the inside of the air distribution pipe 17. A vent pipe 16 is provided on one side of the gas storage tank 8, and the vent pipe 16 is used to connect the air distribution pipe 17 to ensure that the gas inside the gas storage tank 8 can enter the inside of the air distribution pipe 17. A vent pipe 17 is provided on one side of the vent pipe 16, and the air distribution pipe 17 is used to divert the incoming gas so that the gas can reach the protective shell 1, each high-precision filter element 11 inside is blown, and the bottom surface of the air distribution pipe 17 is provided with a plurality of blowing nozzles 18, and the blowing nozzles 18 are used in conjunction with the air distribution pipe 17 to ensure that the gas can blow air to each high-precision filter element 11 inside the protective shell 1, and the bottom end of the conical ash discharge pipe 2 is provided with an ash discharge port 19, and the ash discharge port 19 is used to discharge the dust inside the conical ash discharge pipe 2, and at the same time, it is convenient for the staff to collect the dust to avoid the dust from flying around and causing environmental pollution, and the outer wall of the ash discharge port 19 is provided with a threaded strip 20, and the threaded strip 20 is used in conjunction with the ash discharge closing cover 9 to ensure that the bottom of the conical ash discharge pipe 2 can be freely closed or unblocked.

[0077] Working principle: when filtering, open the filter inlet 6 and the filter outlet 5, connect the filter outlet 5 to the subsequent processing device, and then introduce the high-temperature gas from the filter inlet 6 into the protective shell 1, the gas passes through the high-precision filter element 11 inside the protective shell 1 for filtering and then is discharged from the filter outlet 5 to complete the gas filtering, and when cleaning the dust inside the device, open the gas storage tank 8, and blow the gas from the gas storage tank 8 into the air distribution pipe 17 through the ventilation pipe 16, and then discharge from the blowing nozzle 18 and blow it into the high-precision filter element 11 to blow the high-precision filter element 11 to clean it with dust, when the gas in the gas storage tank 8 is insufficient, open the closed cover of the blowing pipe 7 to connect the gas, and the gas enters from the blowing pipe 7 through the access pipe 15 and then enters the air distribution pipe 17 to blow the high-precision filter element 11 to clean it with dust, and after completion, close the gas storage tank 8 and the blowing pipe 7, and then place a collection box under the conical ash discharge pipe 2, open the ash discharge closed cover 9 at the bottom of the conical ash discharge pipe 2, collect the dust, and complete the dust cleaning inside the device.

[0078] The present invention can also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a high-precision filter element, characterized in that: The steps include: S1: Preparation of SiO2 nanofiber membrane; S2: preparing a cross-linking agent; S3: mixing and dispersing the SiO2 nanofiber membrane, glass fiber, protein and cross-linking agent uniformly, placing them in a mold and drying them to obtain the high-precision filter element; The preparation method of the cross-linking agent comprises adding sodium hyaluronate to a solvent, then adding chlorosilane dropwise to the solution, heating under reflux for reaction, and obtaining the cross-linking agent; The chlorine-containing silane is 3-chloropropyltriethoxysilane, [2-[(chloromethyl)phenyl]ethyl]triethoxysilane, 1-trimethylsilyl-2-(p-chloromethyl)phenylethane or 1-trimethylsilyl-2-(o-chloromethyl)phenylethane; The glass fiber is a nano glass fiber with a fiber length of 3-5 mm and a diameter of 10-15 um; The heating temperature of the heating reflux is 80-120° C., and the reflux time is 5-15 hours; The cross-linking agent structural formula is Formula 1 or Formula 2 or Formula 3 or Formula 4.

2. The method for preparing a high-precision filter element according to claim 1, characterized in that: The S1 specifically comprises: stirring ethyl orthosilicate in an acidic solution, adding PVA solution and stirring evenly to obtain a spinning solution; and performing electrostatic spinning to obtain a SiO2 nanofiber membrane.

3. A high-precision filter element prepared by the preparation method of a high-precision filter element according to any one of claims 1 to 2.

4. A dust removal device for high-temperature flue gas, the dust removal device is provided with a filtering structure, characterized in that: The filtering structure is provided with the high-precision filter element as described in claim 3 above.

5. The dust removal device according to claim 4, characterized in that: A distribution and back-blowing structure is also provided; the reaction gas is evenly distributed through the distribution structure, then passes through the filter element for dust removal, and then passes through the back-blowing structure for online dust cleaning and regeneration.

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