A blast furnace gas filter material

Abstract

The application relates to the field of filter materials, and discloses a blast furnace gas filter material which is made of modified glass fibers and modified aramid fibers and is needled, wherein the modified glass fibers are prepared by the following steps: wrapping glass fibers with polydopamine, growing nanometer silicon dioxide on the surface of the pretreated glass fibers in situ through a sol-gel method, and modifying the nanometer silicon dioxide through dodecyl triethoxysilane low-surface-energy modification; and the modified aramid fibers are prepared by grafting a functional silane coupling agent with aramid fibers, wherein the functional silane coupling agent is prepared by the following steps: preparing an intermediate by reacting cyanuric chloride and diphenylsilanol, grafting two intermediate molecular chains by using N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine, and then grafting 3-chloropropyl triethoxysilane with the obtained cyanuric chloride derivative after the reaction of the cyanuric chloride derivative with DOPO-HQ; the blast furnace gas filter material prepared by the application has excellent mechanical properties and flame-retardant effect, and has good corrosion resistance, ultraviolet resistance and high-temperature resistance.

Description

Technical Field

[0001] This invention belongs to the field of filter material technology, specifically relating to a blast furnace gas filter material. Background Technology

[0002] With rapid economic development and urbanization, air pollution has become a global problem. Baghouse dust collectors are commonly used in industrial dust removal, offering advantages such as high filtration efficiency, insensitivity to dust composition, and abundant fiber raw material sources. However, existing high-temperature fiberglass filter bags suffer from brittle fibers, limiting their ability to withstand low filtration velocities. Meanwhile, conventional needle-punched filter bags exhibit low abrasion resistance and insufficient UV resistance, failing to meet industrial demands for summer and outdoor environments. Furthermore, in blast furnace gas filtration applications such as coal-fired power plants and cement kilns, the fibers used in filter bags must meet requirements for high-temperature resistance and acid / alkali corrosion resistance. Therefore, existing filter bags are difficult to widely apply in the blast furnace gas filtration field. Summary of the Invention

[0003] To address the shortcomings mentioned in the background art, the present invention aims to provide a blast furnace gas filter material, which is made by needle punching modified glass fiber and modified aramid fiber with strong cohesion and entanglement force. It has excellent mechanical properties and flame retardant effect, and has good corrosion resistance, UV resistance and high temperature resistance, while also having good wear resistance and water resistance.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A blast furnace gas filter material is made of modified glass fiber and modified aramid fiber by needle punching. The preparation method includes the following steps: adding modified aramid fiber and modified glass fiber into an opening machine, then feeding the opened and uniformly mixed fiber raw material into a carding machine by quantitative feeding method, and forming a fiber web with the required areal density by cross-laying. Then, the fiber web is needle punched to prepare the blast furnace gas filter material.

[0006] The modified glass fiber is prepared by pretreating the glass fiber with polydopamine, growing nano-silica on the surface of the pretreated glass fiber in situ using the sol-gel method, and then modifying it with low surface energy using dodecyltriethoxysilane.

[0007] The modified aramid fiber is prepared by grafting a functionalized silane coupling agent onto the surface of the aramid fiber. The functionalized silane coupling agent is prepared by a substitution reaction between cyanuric chloride and diphenylsilanol to obtain an intermediate. Then, N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine is used as a bridging agent to graft the molecular chains of the two intermediates. Subsequently, the prepared cyanuric chloride derivative is subjected to a substitution reaction with DOPO-HQ and then grafted with 3-chloropropyltriethoxysilane to form the modified aramid fiber.

[0008] Preferably, the method for preparing the modified glass fiber includes the following steps:

[0009] (1) Take glass fiber and ultrasonically disperse it in deionized water, add dopamine hydrochloride, adjust the pH of the system to 8.5 using Tris alkaline buffer, stir and polymerize at room temperature for 20-24 hours, and then wash with anhydrous ethanol to prepare pretreated glass fiber.

[0010] (2) Take the pretreated glass fiber and ultrasonically disperse it in anhydrous ethanol. Add ammonia water and stir to mix. Heat to 30-35℃, slowly add tetraethyl orthosilicate and dodecyltriethoxysilane and react for 4-5 hours. Then add dodecyltriethoxysilane and react for 2-3 hours to prepare modified glass fiber.

[0011] Preferably, the method for preparing the modified aramid fiber includes the following steps: ultrasonically dispersing aramid fiber in anhydrous ethanol and deionized water, then adding a functionalized silane coupling agent, stirring and reacting at 55-70°C for 4-8 hours, and after the reaction is completed, centrifuging, washing and drying to obtain the modified aramid fiber.

[0012] Preferably, the preparation method of the functionalized silane coupling agent includes the following steps:

[0013] A. Place cyanuric chloride and diphenylsilanol into a reactor containing tetrahydrofuran, and stir the reaction at 40-50°C for 5-6 hours. During the reaction, add triethylamine in batches. After the reaction is completed, filter, evaporate, and dry to prepare the intermediate.

[0014] B. Take the intermediate and N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and put them into a reactor containing m-xylene. Stir the reaction at 55-65°C for 3-5 hours. Then add sodium hydroxide aqueous solution and continue stirring for 3-4 hours. After the reaction is completed, separate the liquid and liquid phases. Wash the organic phase with sodium chloride solution and separate it. Then freeze it, filter it and vacuum dry it to prepare the cyanuric chloride derivative.

[0015] C. Place DOPO-HQ and N,N-dimethylformamide in a reactor and stir at 75-80°C until the solution is colorless and clear. Then add sodium hydroxide and stir to mix. Add cyanuric chloride derivative and react for 4-6 hours. After the reaction is completed, filter, wash and dry to prepare the modified additive.

[0016] D. Take the modified additive, 3-chloropropyltriethoxysilane and triethylamine into a reactor containing tetrahydrofuran, and stir the reaction at 55-70℃ for 3-5 hours. After the reaction is completed, filter, wash and dry to prepare the functionalized silane coupling agent.

[0017] Preferably, the molar ratio of cyanuric chloride and diphenylsilanol in step A is 1:1 to 1.2.

[0018] Preferably, in step B, the molar ratio of N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine to the intermediate is 1:2 to 2.1.

[0019] Preferably, in step C, the molar ratio of DOPO-HQ to cyanuric chloride derivative is 2 to 2.1:1.

[0020] Preferably, the molar ratio of the modified additive and 3-chloropropyltriethoxysilane in step D is 1:2 to 2.3.

[0021] Preferably, the mass ratio of the modified glass fiber to the modified aramid fiber is 1 to 5:1.

[0022] The beneficial effects of this invention are:

[0023] This invention utilizes a substitution reaction between a chlorine atom in cyanuric chloride and a molecule of diphenylsilanol to prepare an intermediate. Then, using N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine as a bridging agent, the two -NH groups in its structure undergo substitution reactions with the chlorine atom in the intermediate structure to prepare a cyanuric chloride derivative. Subsequently, the hydroxyl groups in the two DOPO-HQ molecular chains undergo substitution reactions with the remaining two ungrafted chlorine atoms in the cyanuric chloride derivative to prepare a modified additive. Finally, 3-chloropropyltriethoxysilane undergoes a substitution reaction with the hydroxyl groups at both ends of the modified additive to prepare a functionalized silane coupling agent.

[0024] The functionalized silane coupling agent prepared in this invention incorporates flame-retardant nitrogen, silicon, and phosphorus elements, resulting in excellent flame-retardant performance. It also incorporates a hindered amine light stabilizer, thereby enhancing the UV resistance of the fiber material. Furthermore, the introduced triazine ring exhibits excellent thermal stability; the introduction of the triazine ring into the hindered amine light stabilizer effectively improves its thermal and acid-base stability. This invention utilizes the functionalized silane coupling agent to modify aramid fibers. After hydrolysis, the functionalized silane coupling agent generates Si-OH, which condenses with the silanol groups on the surface of the aramid fiber to form highly water- and heat-resistant Si-O-Si covalent bonds, covering the aramid fiber surface. This not only blocks direct acid and alkali corrosion but also improves mechanical properties to a certain extent. Moreover, the strong chemical bonding endows the aramid fiber with long-lasting UV resistance, thermal stability, and acid-base stability.

[0025] This invention utilizes polydopamine to pretreat glass fibers, and then grows nano-silica in situ on the surface of the pretreated glass fibers using a sol-gel method. The surface energy is further modified with dodecyltriethoxysilane to achieve low surface energy. The glass fibers possess excellent properties such as high strength, high modulus, high temperature resistance, and corrosion resistance. Coating the glass fiber surface with polydopamine enhances the interfacial bonding strength between the nano-silica particles and the glass fiber. The in-situ grown nano-silica particles increase the surface roughness of the glass fiber, enhancing the hydrophobicity and mechanical interlocking of the fiber material. This results in modified glass fibers with excellent mechanical properties, high-temperature resistance, and corrosion resistance. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1: A method for preparing modified glass fiber includes the following steps:

[0028] (1) Take 500 mg of glass fiber and disperse it ultrasonically in 100 mL of deionized water. Add 0.1 g of dopamine hydrochloride and adjust the pH of the system to 8.5 using Tris alkaline buffer. Stir and polymerize at room temperature for 24 h. Then wash with anhydrous ethanol to prepare pretreated glass fiber.

[0029] (2) Take 500 mg of pretreated glass fiber and ultrasonically disperse it in 40 mL of anhydrous ethanol. Add 2 mL of ammonia water and stir to mix. Heat to 30 °C, slowly add 2.1 wt% tetraethyl orthosilicate and 0.01 mL of dodecyltriethoxysilane and react for 5 h. Then add 0.02 mL of dodecyltriethoxysilane and react for 3 h to prepare modified glass fiber.

[0030] Example 2: A method for preparing modified aramid fiber includes the following steps: 500 mg of aramid fiber (2D meta-aramid fiber) is ultrasonically dispersed in 90 mL of anhydrous ethanol and 10 mL of deionized water, and then 1.2 g of functionalized silane coupling agent is added. The mixture is stirred at 65 °C for 5 h. After the reaction is completed, the modified aramid fiber is prepared by centrifugation, washing and drying.

[0031] The preparation method of the functionalized silane coupling agent includes the following steps:

[0032] A. Take 18.4g of cyanuric chloride and 20.1g of diphenylsilanol and put them into a reactor containing 150mL of tetrahydrofuran. Stir and react at 45℃ for 5h. During the reaction, add 10.2g of triethylamine in batches. After the reaction is completed, filter, evaporate and dry to prepare the intermediate.

[0033] B. Take 30.7 g of intermediate (Mr = 348.2) and 17.4 g of N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and put them into a reactor containing 200 mL of m-xylene. Stir the reaction at 60 °C for 4 h. Then add 18 mL of 20% sodium hydroxide aqueous solution and continue stirring for 4 h. After the reaction is completed, separate the liquid and liquid phase. Wash the organic phase with 10% sodium chloride solution and separate it. Then freeze, filter and vacuum dry to prepare cyanuric chloride derivative.

[0034] C. Take 26.1g of DOPO-HQ and 300mL of N,N-dimethylformamide in a reactor, stir at 80℃ until the solution is colorless and clear, then add 6.6g of sodium hydroxide and stir to mix, then add 40.8g of cyanuric chloride derivative (Mr=1018.1) and react for 5h. After the reaction is completed, filter, wash and dry to prepare the modified additive.

[0035] D. Take 15.9g of modified additive (Mr=1593.6), 5.3g of 3-chloropropyltriethoxysilane and 2g of triethylamine and put them into a reactor containing 100mL of tetrahydrofuran. Stir and react at 65℃ for 4h. After the reaction is completed, filter, wash and dry to prepare functionalized silane coupling agent.

[0036] Example 3: A blast furnace gas filter material, which is made by needle punching modified glass fiber prepared in Example 1 and modified aramid fiber prepared in Example 2 at a mass ratio of 1:1.

[0037] The preparation method of the above-mentioned blast furnace gas filter material includes the following steps: adding modified glass fiber and modified aramid fiber into an opening machine for loosening, then feeding the opened and uniformly mixed fiber raw material into a carding machine using a quantitative feeding method, and using a cross-laid web to form a 125g / m² filter material. 2 A fiber web with a surface density of 580 needles / cm² is formed, and then the fiber web is subjected to three needle punches. The first needle punching frequency is 520 r / min, the needle punching depth is 6 mm, and the needle punching density is 580 needles / cm². 2 The second acupuncture session had a frequency of 780 r / min, a depth of 8 mm, and a density of 700 needles / cm². 2 The third acupuncture point had a frequency of 920 r / min, a depth of 14 mm, and a density of 850 needles / cm². 2 A blast furnace gas filter material was prepared.

[0038] Example 4: A blast furnace gas filter material, which is made by needle punching modified glass fiber prepared in Example 1 and modified aramid fiber prepared in Example 2 at a mass ratio of 3:1.

[0039] The preparation method of a blast furnace gas filter material is the same as in Example 3.

[0040] Example 5: A blast furnace gas filter material, which is made by needle punching modified glass fiber prepared in Example 1 and modified aramid fiber prepared in Example 2 at a mass ratio of 5:1.

[0041] The preparation method of a blast furnace gas filter material is the same as in Example 3.

[0042] Comparative Example 1: A method for preparing modified aramid fiber includes the following steps: 500 mg of aramid fiber (2D meta-aramid fiber) is ultrasonically dispersed in 90 mL of anhydrous ethanol and 10 mL of deionized water, and then 1.2 g of functionalized silane coupling agent is added. The mixture is stirred at 65 °C for 5 h. After the reaction is completed, the modified aramid fiber is prepared by centrifugation, washing and drying.

[0043] The preparation method of the functionalized silane coupling agent includes the following steps:

[0044] A. Take 18.4g of cyanuric chloride and 20.1g of diphenylsilanol and put them into a reactor containing 150mL of tetrahydrofuran. Stir and react at 45℃ for 5h. During the reaction, add 10.2g of triethylamine in batches. After the reaction is completed, filter, evaporate and dry to prepare the intermediate.

[0045] B. Take 26.1g of DOPO-HQ and 300mL of N,N-dimethylformamide in a reactor, stir at 80℃ until the solution is colorless and clear, then add 6.6g of sodium hydroxide and stir to mix, then add 14g of intermediate (Mr=348.2) and react for 5h. After the reaction is completed, filter, wash and dry to prepare the modified additive.

[0046] C. Take 9.2g of modified additive (Mr=923.7), 5.3g of 3-chloropropyltriethoxysilane and 2g of triethylamine and put them into a reactor containing 100mL of tetrahydrofuran. Stir and react at 65℃ for 4h. After the reaction is completed, filter, wash and dry to prepare functionalized silane coupling agent.

[0047] Comparative Example 2: A blast furnace gas filter material, which is made by needle punching modified glass fiber prepared in Example 1 and modified aramid fiber prepared in Comparative Example 1 at a mass ratio of 5:1.

[0048] The preparation method of a blast furnace gas filter material is the same as in Example 3.

[0049] Comparative Example 3: A blast furnace gas filter material, which is made by needle punching modified glass fiber and aramid fiber (2D meta-aramid fiber) prepared in Example 1 at a mass ratio of 5:1.

[0050] The preparation method of a blast furnace gas filter material is the same as in Example 3.

[0051] Comparative Example 4: A blast furnace gas filter material, which is made by needle punching glass fiber and modified aramid fiber prepared in Example 2 at a mass ratio of 5:1.

[0052] The preparation method of a blast furnace gas filter material is the same as in Example 3.

[0053] Performance testing

[0054] The performance of the blast furnace gas filter materials prepared in Examples 3-5 and Comparative Examples 2-4 was tested.

[0055] (1) Mechanical property testing: The breaking strength and elongation at break were tested in accordance with FZ / T 60005-1991, and the data results are shown in Table 1.

[0056] (2) Test of acid and alkali corrosion resistance: Sodium hydroxide solution with a mass fraction of 40% and sulfuric acid solution with a mass fraction of 60% were prepared respectively. The samples were soaked at room temperature for 24 hours. After cleaning and drying, the breaking strength of the samples before and after treatment was tested using a YG065H electronic fabric tensile tester. The data results are shown in Table 1.

[0057] (3) UV resistance test: The sample was irradiated under 300W UV light for 24 hours and its breaking strength was tested. The data results are shown in Table 1.

[0058] (4) High temperature resistance test: The sample was placed in an oven and heated to 240℃ at a rate of 2℃ / min and then kept at the temperature for 24h. The fracture strength of the sample before and after treatment was measured. The fracture strength retention rate was used as the evaluation of temperature resistance. The data results are shown in Table 1.

[0059] (5) Abrasion resistance test: Abrasion resistance was tested using a YG(B)522 fabric abrasion tester, with a test area of ​​20 cm². 2 The number of friction cycles was set to 400, and the mass of the sample before and after friction was recorded. The wear resistance of the sample was characterized by the average wear per unit area, and the data results are shown in Table 1.

[0060] (6) Flame retardant performance test: Referring to GB / T 5455-2014, the afterflame time and smoldering time of the samples were measured using the YG815B fabric flame retardant performance tester. The data results are shown in Table 1.

[0061] (7) Water resistance test: After rinsing the sample twice with ethanol, dry it in an oven until constant weight and record the mass M0. Then immerse it in a beaker containing deionized water and let it stand for 48 hours. After that, take it out and place it on a 100-mesh standard sieve. Let it stand for 30 minutes until no liquid drips down and then weigh it and record the mass M1. Perform water absorption test. The water absorption rate is calculated by the following formula: Water absorption rate = (M1-M0) / M0×100%. The data results are shown in Table 1.

[0062] Table 1 Sample performance test results

[0063]

[0064]

[0065] As can be seen from the data in Table 1, the blast furnace gas filter materials prepared in Examples 3-5 of the present invention have excellent mechanical properties and flame retardant effects. They still have high tensile strength after acid and alkali corrosion, ultraviolet irradiation and high temperature treatment. They have excellent corrosion resistance, ultraviolet resistance and high temperature resistance, and also have good wear resistance and water resistance. In Comparative Example 2, the modified aramid fiber without cyanuric chloride derivative grafted onto it showed a significant decrease in tensile strength after UV irradiation compared to Examples 3-5. This was because the hindered amine light stabilizer structure was not introduced. In Comparative Example 3, the aramid fiber was not modified, and its tensile strength after acid and alkali corrosion, UV irradiation, and high-temperature treatment was significantly lower than that of Examples 3-5. Its mechanical properties, flame retardancy, and abrasion and water resistance were also worse than those of Examples 3-5. This indicates that modifying the aramid fiber with a functionalized silane coupling agent significantly improves the overall performance of the aramid fiber. In Comparative Example 4, the glass fiber was not modified, and its tensile strength, elongation at break, and tensile strength after acid and alkali corrosion and high-temperature treatment were lower than those of Examples 3-5. However, its average wear and water absorption were higher than those of Examples 3-5. This indicates that modifying the glass fiber is beneficial for improving the material's mechanical properties, high-temperature resistance, water and abrasion resistance, and corrosion resistance.

[0066] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A blast furnace gas filter material, characterized in that, Made from modified glass fiber and modified aramid fiber by needle punching, the preparation method includes the following steps: adding modified aramid fiber and modified glass fiber into an opening machine, then feeding the opened and uniformly mixed fiber raw material into a carding machine by quantitative feeding method, using cross-laying to form a fiber web with the required surface density, and then needle punching the fiber web to prepare blast furnace gas filter material; The method for preparing the modified glass fiber includes the following steps: (1) Take glass fiber and ultrasonically disperse it in deionized water, add dopamine hydrochloride, adjust the pH of the system to 8.5 using Tris alkaline buffer, stir and polymerize at room temperature for 20-24 h, and then wash with anhydrous ethanol to prepare pretreated glass fiber; (2) Take the pretreated glass fiber and ultrasonically disperse it in anhydrous ethanol. Add ammonia water and stir to mix. Heat to 30~35℃, slowly add tetraethyl orthosilicate and dodecyltriethoxysilane and react for 4~5h. Then add dodecyltriethoxysilane and react for 2~3h to prepare modified glass fiber. The preparation method of the modified aramid fiber includes the following steps: aramid fiber is ultrasonically dispersed in anhydrous ethanol and deionized water, then a functionalized silane coupling agent is added, and the mixture is stirred and reacted at 55~70℃ for 4~8h. After the reaction is completed, the modified aramid fiber is obtained by centrifugation, washing and drying. The preparation method of the functionalized silane coupling agent includes the following steps: A. Place cyanuric chloride and diphenylsilanol into a reactor containing tetrahydrofuran, and stir the reaction at 40~50℃ for 5~6 hours. During the reaction, add triethylamine in batches. After the reaction is completed, filter, evaporate and dry to prepare the intermediate. B. Take the intermediate and N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and put them into a reactor containing m-xylene. Stir the reaction at 55~65℃ for 3~5h. Then add sodium hydroxide aqueous solution and continue stirring for 3~4h. After the reaction is completed, separate the liquid and liquid phases. Wash the organic phase with sodium chloride solution and separate it. Then freeze it, filter it and vacuum dry it to prepare cyanuric chloride derivative. C. Place DOPO-HQ and N,N-dimethylformamide in a reactor and stir at 75~80℃ until the solution is colorless and clear. Then add sodium hydroxide and stir to mix. Add cyanuric chloride derivative and react for 4~6 hours. After the reaction is completed, filter, wash and dry to prepare the modified additive. D. Take the modified additive, 3-chloropropyltriethoxysilane and triethylamine and put them into a reactor containing tetrahydrofuran. Stir the reaction at 55~70℃ for 3~5h. After the reaction is completed, filter, wash and dry to prepare the functionalized silane coupling agent.

2. The blast furnace gas filter material according to claim 1, characterized in that, In step A, the molar ratio of cyanuric chloride and diphenylsilanol is 1:1 to 1.

2.

3. The blast furnace gas filter material according to claim 1, characterized in that, In step B, the molar ratio of N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine to the intermediate is 1:2~2.

1.

4. The blast furnace gas filter material according to claim 1, characterized in that, In step C, the molar ratio of DOPO-HQ to cyanuric chloride derivative is 2~2.1:

1.

5. The blast furnace gas filter material according to claim 1, characterized in that, In step D, the molar ratio of the modified additive and 3-chloropropyltriethoxysilane is 1:2~2.

3.

6. The blast furnace gas filter material according to claim 1, characterized in that, The mass ratio of the modified glass fiber to the modified aramid fiber is 1~5:1.

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