Method for directionally dissociating glass fibers from retired wind turbine blades, glass fibers and applications thereof

Abstract

The present invention relates to the field of solid waste treatment, and discloses a method for directionally dissociating glass fibers from retired wind turbine blades, glass fibers, and applications thereof. The method comprises: cutting the wind turbine blades into blocks; soaking the blocks in a swelling agent and a silane coupling agent; reacting the aforementioned product with a degradation agent and an additive, wherein the additive contains an organosilicon reagent and an organic acid; and finally soaking the aforementioned product in an organic acid. The present invention removes the resin material in the wind turbine blades by swelling and degradation; the glass fibers are protected by silane coupling agents and organosilicon reagents to prevent them from being worn and broken during the swelling and degradation process. The present invention also modifies acid sites on the surface of the glass fibers by soaking and acidifying with organic acids; the acid area of ​​the glass fibers obtained by this method is increased by 37.15%, which is beneficial to the resource utilization of glass fibers in the fields of denitrification catalysis, conductive fibers, etc.

Description

Technical Field

[0001] The present invention relates to the field of solid waste treatment, and in particular to a method for directionally dissociating glass fibers from retired wind turbine blades, the glass fibers, and applications thereof. Background Art

[0002] Wind power generation is an important low-carbon development strategy. my country's wind power industry is developing rapidly, and market demand for wind power materials is growing rapidly. However, wind turbine materials have a limited design lifespan, and the disposal of these materials after retirement is becoming increasingly challenging.

[0003] The most difficult materials to dispose of during decommissioning are the blades. Blades are primarily composed of a composite material of fiber and resin, with glass fiber comprising the largest proportion. Discarding these materials can lead to significant waste of resources and environmental pollution.

[0004] Glass fiber can be used as a reinforcing agent in many fields. The acid sites on the glass fiber surface can be modified, further broadening its application channels and increasing its added value. However, simply recycling glass fiber from wind turbine blades will make it difficult to replace existing glass fiber on the market due to wear and breakage during processing. Modifying the poorly performing recycled glass fiber will increase the processing steps and process flow. Therefore, it is necessary to add a certain activation step to the fiber recycling process to ensure that the resulting glass fiber has good mechanical and chemical properties, increase competitive advantages, and expand application scenarios. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems in the prior art of recycling glass fibers from retired wind turbine blades that are prone to fiber wear and breakage, and the mechanical and chemical properties of the recycled glass fibers are poor, resulting in narrow resource utilization channels. A method for directionally dissociating glass fibers from retired wind turbine blades is provided. The method retains the good fiber strength of the recycled glass fibers by adding silane coupling agents and organosilicon reagents during the recycling process, thereby avoiding wear and breakage of the glass fibers during the swelling process. The method also acidifies and modifies the glass fibers by adding organic acids during the recycling process, thereby increasing the acid sites on the surface of the glass fibers, optimizing their chemical properties, and facilitating the resource recycling of the glass fibers. At the same time, the method retains the mechanical properties and improves the chemical properties of the glass fibers during the recycling process, thereby reducing the process flow and improving the economic benefits. The glass fibers recovered by the method have high fiber strength and good chemical properties, and can be used in the catalytic field as a reinforcing material in the catalyst molding process, while improving the catalytic performance of the catalyst.

[0006] In order to achieve the above object, the first aspect of the present invention provides a method for directionally dissociating glass fibers from retired wind turbine blades, the method comprising the following steps:

[0007] (1) Cutting wind turbine blades into blocks;

[0008] (2) immersing the block in a mixture containing a swelling agent and a silane coupling agent;

[0009] (3) mixing a degradation agent, an additive, and the solid product obtained in step (2) to react, wherein the additive contains an organosilicon reagent and an organic acid, and the reaction conditions include: a temperature of 90-400° C. and a time of ≥1 h;

[0010] (4) Soaking the solid product obtained in step (3) in an organic acid solution.

[0011] Preferably, the block is a hexahedron.

[0012] Preferably, in step (2), the swelling agent is selected from one or more of carbon tetrachloride, methanol and dichloromethane.

[0013] Preferably, in step (2), the silane coupling agent is tetramethyl orthosilicate and / or tetraethyl orthosilicate.

[0014] Preferably, in step (2), the liquid-to-solid ratio of the total amount of the swelling agent and the silane coupling agent to the amount of the block is ≥10 mL:1 g.

[0015] Preferably, in step (2), the volume ratio of the swelling agent to the silane coupling agent is 10-100:1.

[0016] Preferably, in step (2), the soaking conditions include: temperature of 90-150° C., time ≥30 min.

[0017] Preferably, in step (3), the degradation agent is selected from one or more of tetralin, decalin, cyclohexanol, ethylene glycol, diethylene glycol and triethylene glycol.

[0018] Preferably, in step (3), the organic acid is selected from one or more of citric acid, acetic acid, oxalic acid, sulfinic acid and ascorbic acid.

[0019] Preferably, in step (3), the organosilicon reagent is selected from one or more of methyltrimethoxysilane, fatty triisopropylsilane, fatty alcohol polyoxyethylene ether methyl silane, dimethoxy(methyl)silane, trimethoxysilane, octamethyltrisiloxane, and N,O-bis(trimethylsilyl)acetamide.

[0020] Preferably, in step (3), the volume ratio of the organosilicon reagent to the organic acid is 0.02-2:1.

[0021] Preferably, in step (3), the volume ratio of the degradation agent to the additive is 5-50:1.

[0022] Preferably, in step (3), the liquid-to-solid ratio of the total amount of the degradation agent and the additive to the amount of the solid product obtained in step (2) is 5-60 mL:1 g.

[0023] Preferably, in step (4), the organic acid is selected from one or more of citric acid, acetic acid, oxalic acid, sulfinic acid and ascorbic acid.

[0024] Preferably, in step (4), the liquid-to-solid ratio of the organic acid to the solid product obtained in step (3) is ≥5 mL:1 g.

[0025] Preferably, in step (4), the soaking conditions include: temperature of 40-90° C. and time of 60-120 min.

[0026] A second aspect of the present invention provides a glass fiber prepared by the method described above.

[0027] The third aspect of the present invention provides a use of the glass fiber prepared by the method described above in an acidic catalyst.

[0028] The technical solution of the present invention has at least the following advantages compared with the prior art:

[0029] (1) The method of the present invention removes the resin material from the wind turbine blades through a swelling degradation process, and the addition of a silane coupling agent during the glass fiber recovery process preserves the fiber strength of the glass fiber. The addition of an organosilicon reagent can further completely degrade the resin in the retired wind turbine blades, and the combined use of the silane coupling agent and the organosilicon reagent minimizes wear and breakage of the glass fiber during the swelling degradation process. In a preferred embodiment, the glass fiber recovered by this method has a fiber length of 3 mm or longer, accounting for up to 76.38%, and a strength loss rate of only 2-3%, which is advantageous for use as a reinforcing material in the molding process of acid catalysts.

[0030] (2) The method of the present invention further degrades the resin contained in retired wind turbine blades through organic acid immersion, while also modifying acidic sites on the glass fiber surface. In a preferred embodiment, the acidic area on the glass fiber surface is increased by 37.15%, which is beneficial for the resource utilization of the glass fiber in fields such as acid catalysts and conductive fibers.

[0031] (3) The method described in the present invention is simple to operate and has low raw material costs. It can retain the mechanical properties of the glass fiber and improve its chemical properties during the recycling process, thus avoiding the two-step operation of first recycling solid waste and then modifying it in the prior art, simplifying the process and improving economic benefits.

[0032] (4) In the present invention, the glass fiber recovered by the method has a low fiber strength loss rate and a large acidic area, and can be used as a reinforcing material in the field of acid catalyst molding, while also having certain catalytic performance. In a preferred embodiment, the glass fiber is used in the field of catalytic denitrification. The glass fiber participates in flue gas denitrification catalysis at 300°C, and the denitrification rate can reach 41.22%, which can improve the competitiveness of the glass fiber in the application of denitrification catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a photo taken with a mobile phone showing the appearance of the glass fiber in the retired wind turbine blades recovered in Example 1. DETAILED DESCRIPTION

[0034] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0035] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0036] In one aspect, the present invention provides a method for directionally dissociating and modifying glass fibers from retired wind turbine blades, the method comprising the following steps:

[0037] (1) Cutting wind turbine blades into blocks;

[0038] (2) immersing the block in a mixture containing a swelling agent and a silane coupling agent;

[0039] (3) mixing a degradation agent, an additive, and the solid product obtained in step (2) to react, wherein the additive contains an organosilicon reagent and an organic acid, and the reaction conditions include: a temperature of 90-400° C. and a time of ≥1 h;

[0040] (4) Soaking the solid product obtained in step (3) in an organic acid solution.

[0041] In a specific embodiment, the wind turbine blade contains core material, resin and glass fiber.

[0042] In a preferred embodiment, the core material of the wind turbine blade may be balsa wood and / or PVC, and the resin may be one or more of epoxy resin, unsaturated polyester resin and epoxy vinyl ester resin.

[0043] In a preferred embodiment, the glass fiber content in the wind turbine blade is 50-70%, and the total content of resin and core material is 20-50%, wherein the core material is mainly distributed in part of the resin material and glass fiber, and the overall content in the blade is small and can be ignored.

[0044] In a specific embodiment, the wind turbine blade can be cut into hexahedrons manually or by machine, as long as the purpose of the present invention can be achieved. In a preferred embodiment, the side length of the hexahedron is ≤10 cm.

[0045] In a further preferred embodiment, the block may be a regular cube or a cuboid.

[0046] In a specific embodiment, in step (2), the swelling agent can be any conventionally selected agent in the art, as long as the purpose of the present invention can be achieved. In a preferred embodiment, in step (2), the swelling agent can be one or more of carbon tetrachloride, methanol, and dichloromethane.

[0047] In a further preferred embodiment, in step (2), the swelling agent may be carbon tetrachloride and / or dichloromethane, specifically carbon tetrachloride, dichloromethane, a mixture of carbon tetrachloride and dichloromethane at a volume ratio of 1:1, or a mixture of carbon tetrachloride and dichloromethane at a volume ratio of 2:1. In this preferred embodiment, carbon tetrachloride and / or dichloromethane can effectively penetrate and swell the resin in the retired wind turbine blades, creating gaps between the resin and the glass fiber, facilitating subsequent degradation operations.

[0048] In a specific embodiment, in step (2), the silane coupling agent can be any conventional silane coupling agent in the art, as long as it can achieve the purpose of the present invention. In a preferred embodiment, it is tetraethyl orthosilicate and / or tetramethyl orthosilicate. According to this preferred embodiment, the silane coupling agent is coated on the surface of the glass fiber and undergoes hydrolysis, which is beneficial for retaining the fiber strength of the glass fiber.

[0049] In a specific embodiment, in step (2), the liquid-to-solid ratio of the total amount of the swelling agent and the silane coupling agent to the amount of the block is ≥10 mL:1 g.

[0050] In a preferred embodiment, in step (2), the liquid-to-solid ratio of the total amount of the swelling agent and the silane coupling agent to the amount of the block can be 10-50 mL:1 g. Specifically, it can be: 10 mL:1 g, 15 mL:1 g, 20 mL:1 g, 25 mL:1 g, 30 mL:1 g, 35 mL:1 g, 40 mL:1 g, 45 mL:1 g, or 50 mL:1 g.

[0051] In a specific embodiment, in step (2), the volume ratio of the swelling agent to the silane coupling agent can be 10-100:1.

[0052] In a preferred embodiment, in step (2), the volume ratio of the swelling agent to the silane coupling agent may be 20-50:1, specifically 20:1, 25:1, 30:1, 35:1, 40:1, 45:1 or 50:1.

[0053] In a specific embodiment, in step (2), the soaking conditions can be selected from conventional conditions in the art, as long as the purpose of the present invention can be achieved. The soaking temperature and soaking time are adjusted according to the applicable temperatures of the swelling agent and the silane coupling agent. In a preferred embodiment, the soaking conditions include: a temperature of 90-150°C and a time of ≥30 minutes.

[0054] In a further preferred embodiment, in step (2), the soaking conditions include: temperature of 120-140° C., and time of 60-120 min.

[0055] In the present invention, the resin material in the retired wind turbine blades is immersed and swelled in a swelling agent, which is beneficial to subsequent degradation; during the swelling process, the silane coupling agent penetrates into the gaps between the resin material and the fiber material and is coated on the surface of the glass fiber, hydrolyzing the surface of the glass fiber, thereby retaining the fiber strength of the glass fiber and avoiding wear and breakage of the glass fiber; and through the preferred embodiment described above, the swelling effect during the recycling process is the best, and the separation effect between the resin material and the glass fiber is better, which is beneficial to the penetration and coating of the silane coupling agent and the penetration and degradation of the degradation agent in subsequent treatment, so that the obtained glass fiber has minimal wear and the highest fiber strength.

[0056] In a specific embodiment, in step (3), the degradation agent can be any conventionally selected agent in the art, as long as it can achieve the purpose of the present invention. In a preferred embodiment, the degradation agent can be one or more of tetralin, decalin, cyclohexanol, ethylene glycol, diethylene glycol, and triethylene glycol.

[0057] In a further preferred embodiment, in step (3), the degradation agent may be ethylene glycol and / or tetralin. With this preferred embodiment, the degradation agent has the best degradation effect on the resin material, and its good fluidity facilitates penetration into gaps in the resin material, resulting in high degradation efficiency.

[0058] In a specific embodiment, in step (3), the organic acid can be any conventional choice in the art, as long as it can achieve the purpose of the present invention. In a preferred embodiment, it can be one or more of citric acid, acetic acid, oxalic acid, sulfinic acid and ascorbic acid.

[0059] In a further preferred embodiment, in step (3), the organic acid may be acetic acid, sulfinic acid or ascorbic acid.

[0060] In a specific embodiment, in step (3), the organosilicon reagent can be one or more of methyltrimethoxysilane, fatty triisopropylsilane, fatty alcohol polyoxyethylene ether methyl silane, dimethoxy(methyl)silane, trimethoxysilane, octamethyltrisiloxane, and N,O-bis(trimethylsilyl)acetamide.

[0061] In a specific embodiment, in step (3), the volume ratio of the organosilicon reagent to the organic acid can be 0.02-2:1.

[0062] In a preferred embodiment, in step (3), the volume ratio of the organosilicon reagent to the organic acid may be 0.1-2:1, specifically 0.1:1, 0.3:1, 0.5:1, 0.8:1, 1.0:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1 or 2.0:1.

[0063] In a specific embodiment, in step (3), the liquid-to-solid ratio of the total amount of the degradation agent and the additive to the amount of the solid product obtained in step (2) can be 5-60 mL:1 g.

[0064] In a preferred embodiment, in step (3), the liquid-to-solid ratio of the total amount of the degradation agent and the additive to the amount of the product obtained in step (2) can be 15-35 mL:1 g. Specifically, it can be: 15 mL:1 g, 20 mL:1 g, 25 mL:1 g, 30 mL:1 g, or 35 mL:1 g.

[0065] In a specific embodiment, in step (3), the volume ratio of the degradation agent to the additive can be 5-50:1.

[0066] In a preferred embodiment, in step (3), the volume ratio of the degradation agent to the additive may be 5-35:1, specifically 5:1, 10:1, 15:1, 20:1, 25:1, 30:1 or 35:1.

[0067] In a specific embodiment, in step (3), the reaction conditions include: a temperature of 90-400°C and a time of ≥1 hour. The reaction temperature and time are selected based on the properties of the degradation agent, the organosilicon reagent, and the organic acid to avoid evaporation of the selected degradation agent or decomposition of the organic acid, while ensuring complete degradation of the resin material in the retired wind turbine blade.

[0068] In a preferred embodiment, in step (3), the reaction conditions include: temperature of 160-250°C, time of 1-3 hours, and specific temperatures may be: 160°C, 180°C, 200°C, 220°C, or 250°C.

[0069] In the present invention, the resin and core material in the retired wind turbine blades are eluted by a degradation agent to dissociate the glass fibers in the retired wind turbine blades; the organic silicon reagent penetrates into the resin material to assist in degradation, while avoiding physical wear and breakage of the glass fibers during the degradation process, and avoiding the loss of silicon in the glass fibers during the degradation process to damage the chemical properties of the glass fibers; the glass fibers are acidified and modified by organic acids, which can modify the acid sites on the surface of the glass fibers and avoid corrosion of the glass fibers by inorganic acids, thereby facilitating the application of the glass fibers in fields such as acid catalysts.

[0070] In a specific embodiment, in step (4), the organic acid can be any conventionally selected organic acid in the art, as long as it can achieve the purpose of the present invention. In a preferred embodiment, it is one or more of citric acid, acetic acid, oxalic acid, sulfinic acid and ascorbic acid.

[0071] In a further preferred embodiment, in step (4), the organic acid may be citric acid.

[0072] In a specific embodiment, in step (4), the liquid-to-solid ratio of the organic acid to the solid product obtained in step (3) is ≥5 mL:1 g.

[0073] In a preferred embodiment, in step (4), the liquid-to-solid ratio of the organic acid to the product obtained in step (3) may be 10-35 mL:1 g, specifically 10 mL:1 g, 15 mL:1 g, 20 mL:1 g, 25 mL:1 g, 30 mL:1 g, or 35 mL:1 g.

[0074] In a specific embodiment, in step (4), the soaking conditions include: temperature of 40-90° C. and time of 60-120 min.

[0075] In a specific embodiment, in step (2), step (3) and step (4), the obtained product needs to be subjected to solid-liquid separation, washing and drying.

[0076] In a specific embodiment, in step (2), step (3) and step (4), the solid-liquid separation can be a conventional choice in the field, as long as the purpose of the present invention can be achieved.

[0077] In a specific embodiment, in step (2), step (3) and step (4), the detergent can be any conventional detergent in the art, as long as the purpose of the present invention can be achieved. In a preferred embodiment, the detergent can be one or more of ethanol, water and acetone.

[0078] In a specific embodiment, in step (2), step (3) and step (4), the drying temperature can be selected conventionally in the art, as long as the purpose of the present invention can be achieved. In a preferred embodiment, the temperature can be 60-100°C.

[0079] In the present invention, by further immersing the glass fiber in an organic acid, the alkaline oxide in the glass fiber is further acidified, and the acid sites on the surface of the glass fiber are further increased, which can improve the auxiliary catalytic performance of the glass fiber in the catalytic denitrification process.

[0080] A second aspect of the present invention provides a glass fiber prepared by the method described above.

[0081] The third aspect of the present invention provides a use of the glass fiber prepared by the method described above in an acidic catalyst.

[0082] In the present invention, the glass fiber recovered by the above method has a low fiber strength loss rate and a large acidic area, and can be used as a reinforcing material in the field of acid catalyst molding, while also having certain catalytic performance. In a preferred embodiment, the glass fiber can be used in the field of catalytic denitrification. The glass fiber participates in the flue gas denitrification catalysis at 300°C, and the denitrification rate can reach 41.22%, which can improve the competitiveness of the glass fiber in the application of denitrification catalysts.

[0083] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0084] In the following embodiments and comparative examples, the retired wind turbine blades are retired wind turbine blades from a wind farm in Liaoning.

[0085] In the following examples and comparative examples, unless otherwise specified, all reagents used are commercially available products.

[0086] Example 1

[0087] (1) Cutting the retired wind turbine blades into cubes (5 cm×5 cm×5 cm), wherein the fiber content in the retired wind turbine blades is 56.44%, and the total content of the resin and the core material is 40.36%;

[0088] (2) carbon tetrachloride, dichloromethane, and tetramethyl orthosilicate are mixed to obtain solution A, wherein the volume ratio of carbon tetrachloride, dichloromethane, and tetramethyl orthosilicate is 15:15:1; solution A having a liquid-to-solid ratio of 15 mL:1 g is mixed with the cube and placed in a reactor, reacted at 120° C. for 90 min, and after the reaction is completed, the swollen block is taken out, and the obtained product is washed with acetone, ethanol, and water in sequence, and dried at 80° C.;

[0089] (3) Ethylene glycol, methyltrimethoxysilane and sulfinic acid are mixed to obtain solution B, wherein the volume ratio of ethylene glycol, methyltrimethoxysilane and sulfinic acid is 20:1:1; solution B having a liquid-to-solid ratio of 30 mL:1 g is mixed with the product obtained in step (2), and the mixture is reacted and degraded at 250° C. for 120 min. After the reaction is completed, the mixture is filtered, and the obtained solid product is washed with acetone and ethanol, and then dried at 80° C. to constant weight;

[0090] (4) mixing the product obtained in step (3) with a citric acid solution, acidifying at 60° C. for 60 min, and then filtering to obtain the glass fiber, wherein the liquid-to-solid ratio of the citric acid solution to the product obtained in step (3) is 10 mL:1 g, and the concentration of the citric acid solution is 0.2 mol / L; washing the glass fiber with deionized water, drying at 80° C. to constant weight, to obtain bundled glass fiber, and screening to select the bundled glass fiber with a diameter of 3 mm or more.

[0091] Example 2

[0092] (1) Cutting the retired wind turbine blades into rectangular parallelepipeds (5 cm×6 cm×6 cm), wherein the fiber content of the retired wind turbine blades is 56.44%, and the total content of the resin and the core material is 40.36%;

[0093] (2) carbon tetrachloride, dichloromethane and tetramethyl orthosilicate are mixed to obtain solution A, wherein the volume ratio of carbon tetrachloride, dichloromethane and tetramethyl orthosilicate is 40:20:3; solution A with a liquid-to-solid ratio of 15 mL:1 g is mixed with the cube and placed in a reactor, reacted at 130° C. for 90 minutes, and after the reaction is completed, the swollen block is taken out, and the obtained product is washed with acetone, ethanol and water in sequence, and dried at 80° C.;

[0094] (3) Ethylene glycol, methyltrimethoxysilane and acetic acid are mixed to obtain solution B, wherein the volume ratio of ethylene glycol, methyltrimethoxysilane and acetic acid is 20:2:1; solution B having a liquid-to-solid ratio of 30 mL:1 g is mixed with the product obtained in step (2), and the mixture is reacted and degraded at 240° C. for 120 min. After the reaction is completed, the mixture is filtered, and the obtained solid product is washed with acetone and ethanol, and then dried at 80° C. to constant weight;

[0095] (4) mixing the product obtained in step (3) with a citric acid solution, acidifying at 60° C. for 80 min, and then filtering to obtain the glass fiber, wherein the liquid-to-solid ratio of the citric acid solution to the product obtained in step (3) is 10 mL:1 g, and the concentration of the citric acid solution is 0.4 mol / L; washing the glass fiber with deionized water, drying at 80° C. to constant weight, to obtain bundled glass fiber, and screening to select the bundled glass fiber with a diameter of 3 mm or more.

[0096] Example 3

[0097] (1) Cutting a wind turbine blade into a cube (6 cm×6 cm×6 cm), wherein the fiber content in the wind turbine blade is 61.22%, and the total content of the resin and the core material is 34.53%;

[0098] (2) mixing dichloromethane and tetraethyl orthosilicate to obtain solution A, wherein the volume ratio of dichloromethane to tetramethyl orthosilicate is 20:1; mixing solution A with a liquid-to-solid ratio of 15 mL:1 g with the cube and placing it into a reactor, reacting at 140° C. for 90 minutes, and after the reaction is completed, taking out the swollen block, washing the obtained product with acetone, ethanol and water in sequence, and drying it at 80° C.;

[0099] (3) tetralin, triisopropylsilane and ascorbic acid are mixed to obtain solution B, wherein the volume ratio of tetralin, triisopropylsilane and ascorbic acid is 20:1:2; solution B having a liquid-to-solid ratio of 30 mL:1 g is mixed with the product obtained in step (2), and the mixture is reacted and degraded at 160° C. for 120 min. After the reaction is completed, the mixture is filtered, and the obtained solid product is washed with acetone and ethanol, and then dried at 80° C. to a constant weight;

[0100] (4) mixing the product obtained in step (3) with a citric acid solution, acidifying at 60° C. for 90 min, and then filtering to obtain the glass fiber, wherein the liquid-to-solid ratio of the citric acid solution to the glass fiber is 10 mL:1 g, and the concentration of the citric acid solution is 0.58 mol / L; washing the glass fiber with deionized water, and drying at 80° C. to constant weight to obtain bundled glass fibers, and screening to select the bundled glass fibers with a thickness of 3 mm or more.

[0101] Comparative Example 1

[0102] This comparative example was carried out according to the method of Example 1, except that in step (2), tetramethyl orthosilicate was not added.

[0103] Comparative Example 2

[0104] This comparative example was carried out according to the method of Example 1, except that in step (3), methyltrimethoxysilane and sulfinic acid were not added; and in step (4), citric acid solution was not used for soaking.

[0105] Comparative Example 3

[0106] This comparative example was carried out according to the method of Example 1, except that in step (3), the reaction degradation temperature was 80° C. and the reaction time was 4 h.

[0107] Comparative Example 4

[0108] This comparative example was carried out according to the method of Example 1, except that in step (2), carbon tetrachloride and dichloromethane were not added.

[0109] Comparative Example 5

[0110] This comparative example was carried out according to the method of Example 1, except that in step (4), the citric acid solution was replaced by a nitric acid solution of the same concentration.

[0111] Comparative Example 6

[0112] This comparative example is commercially available chopped glass fibers for catalyst reinforcement.

[0113] Test Example 1

[0114] Characterization of fiber strength loss of the glass fibers recovered in Examples 1-3 and Comparative Examples 1-5: The tensile strength of the glass fibers recovered in the Examples and Comparative Examples was tested according to the method of ASTM C1557-2003 "Standard Test Method for Tensile Strength and Young's Modulus of Fibers". The tensile strength of the commercially available glass fiber raw materials added during the production of wind turbine blades was also tested. The length of the glass fibers used in the test examples was equivalent to that of the commercially available glass fiber raw materials. The tensile strength loss rate of the recovered glass fibers was calculated according to the following formula:

[0115] Glass fiber tensile strength loss rate = (tensile strength of commercial glass fiber raw material - tensile strength of recycled glass fiber) / tensile strength of glass fiber raw material × 100%;

[0116] The results are shown in Table 1.

[0117] Test Example 2

[0118] Characterization of the fiber acid area increase ratio of the glass fibers recovered in Examples 1-3 and Comparative Examples 1-5: The acid site area of ​​the glass fibers recovered in Examples 1-3 and Comparative Examples 1-5, as well as the commercially available catalyst-reinforced chopped glass fibers in Comparative Example 6, was tested by NH3-TPD. The acid amount calculated from the NH3-TPD spectrum should actually be the total acid amount. The fiber acid area increase ratio of the recovered glass fibers was calculated according to the following formula:

[0119] Fiber acid area enhancement ratio = (acidity of recovered glass fiber - acidity of commercial catalyst-reinforced chopped glass fiber) / acidity of commercial catalyst-reinforced chopped glass fiber × 100%;

[0120] The results are shown in Table 1.

[0121] Test Example 3

[0122] Characterization of the catalytic activity of the glass fibers in Examples 1-3 and Comparative Examples 1-6 in catalytic denitrification: Take appropriate amounts of the glass fiber products recovered in Examples 1-3 and Comparative Examples 1-5 and the commercially available chopped glass fiber products for catalyst enhancement in Comparative Example 6 and load them into a catalyst performance evaluation reaction device. The simulated gas of industrial boiler exhaust is introduced to evaluate the catalytic activity of the glass fibers in Examples 1-3 and Comparative Examples 1-6. The simulated gas composition is as follows: 500 ppm of NO, 400 ppm of NH3, 10.00% of O2, 12% of water, and the rest is nitrogen. The simulated gas is introduced into the denitrification reactor for reaction at a reaction temperature of 300°C. The concentration of nitrogen oxides in the flue gas before and after the reaction is analyzed using a 42i-HL flue gas analyzer, and then the denitrification rate of the denitrification catalyst is calculated;

[0123] The concentration of nitrogen oxides in the flue gas before the reaction is a, and the concentration of nitrogen oxides in the flue gas after the reaction is b. The calculation formula for the denitrification rate of the denitrification catalyst is: η = (a-b) / a×100%;

[0124] The results are shown in Table 1.

[0125] Table 1

[0126]

[0127] It can be seen from the results in Table 1 that by adopting the technical solution of the present invention, the bundled glass fibers obtained in Examples 1-3 have a lower wear rate and a higher fiber strength. The glass fibers obtained in Example 1 account for 76.38% of those with a diameter of 3 mm or more, and the fiber strength loss rate is 2.33%, which is significantly better than the performance of the glass fibers recovered in Comparative Examples 1-5. Moreover, the bundled modified glass fibers obtained in Examples 1-3 have a larger fiber acid area. In the catalytic denitrification test, they have catalytic performance that is significantly better than the glass fibers recovered in Comparative Examples 1-5 and the commercially available chopped glass fibers for catalyst reinforcement in Comparative Example 6. They can be subsequently used in the industrial production of denitrification catalysts or other acidic catalysts.

[0128] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for directionally dissociating glass fibers from retired wind turbine blades, characterized in that: The method comprises the following steps: (1) Cutting wind turbine blades into blocks; (2) immersing the block in a mixture containing a swelling agent and a silane coupling agent, wherein the volume ratio of the swelling agent to the silane coupling agent is 20-50:1; (3) mixing a degradation agent, an additive, and the solid product obtained in step (2) to react, wherein the additive contains an organosilicon reagent and an organic acid; The volume ratio of the silane to the organic acid is 0.02-2:1; The volume ratio of the degradation agent to the additive is 5-50:1; The reaction conditions include: temperature of 90-400°C, time ≥1h; (4) soaking the solid product obtained in step (3) in an organic acid solution; Wherein, the silane coupling agent is tetramethyl orthosilicate and / or tetraethyl orthosilicate; The degradation agent is selected from one or more of tetralin, decalin, cyclohexanol, ethylene glycol, diethylene glycol and triethylene glycol; The organic acid is selected from one or more of citric acid, acetic acid, oxalic acid, sulfinic acid and ascorbic acid; The organosilicon reagent is selected from one or more of methyltrimethoxysilane, triisopropylsilane, fatty alcohol polyoxyethylene ether methylsilane, dimethoxy(methyl)silane, trimethoxysilane, octamethyltrisiloxane, and N,O-bis(trimethylsilyl)acetamide.

2. The method according to claim 1, characterized in that The block is a hexahedron.

3. The method according to claim 1 or 2, characterized in that In step (2), the swelling agent is selected from one or more of carbon tetrachloride, methanol and dichloromethane.

4. The method according to claim 1 or 2, characterized in that In step (2), the liquid-to-solid ratio of the total amount of the swelling agent and the silane coupling agent to the amount of the block is ≥10 mL:1 g.

5. The method according to claim 1 or 2, characterized in that In step (2), the soaking conditions include: temperature of 90-150°C and time ≥30 min.

6. The method according to claim 1 or 2, characterized in that In step (3), the liquid-to-solid ratio of the total amount of the degradation agent and the additive to the amount of the solid product obtained in step (2) is 5-60 mL: 1 g.

7. The method according to claim 1 or 2, characterized in that In step (4), the liquid-to-solid ratio of the organic acid to the solid product obtained in step (3) is ≥5 mL:1 g; And / or, in step (4), the soaking conditions include: temperature of 40-90° C. and time of 60-120 min.

8. Glass fiber prepared by the method according to any one of claims 1 to 7.

9. Use of the glass fiber according to claim 8 in an acidic catalyst.

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