Compound Auxiliary Agent, Recycling Method and Recycling System for Recycling Wind Turbine Blade Composites

Abstract

The present invention provides a compounding aid, a recycling method and a recycling system for recycling wind power blade composite materials. The compounding aid comprises component A and component B, and the mass ratio of the two is 1:5 to 5:1. Among them, component A is an organic alcohol, and component B is an organic acid. The compounding aid for wind power blade composite materials provided by this application recycles wind power blade composite materials through the mutual cooperation of component A of organic alcohol and component B of organic acid with a specific mass ratio. It not only has a simple process, low energy consumption, is green and environmentally friendly, but also has a high degradation rate. The degree of damage to the fibers in the recycled product is small, the loss rate is low, the recovery rate is ≥95%, and the purity is high, with extremely little resin residue, which is more conducive to the recycling of the fibers in the recycled product.

Description

Technical Field

[0001] The present invention relates to the technical field of material recycling, and in particular, to a compounding aid for recycling wind turbine blade composites, a recycling method, and a recycling system. Background Art

[0002] Wind turbine blades are mainly made of carbon fiber or glass fiber and resin, which also provides the necessary strength and flexibility for efficient power generation. However, these materials are not biodegradable and take hundreds of years to decompose in landfills. In addition, the large size of the blades, which can be up to 300 feet long, poses challenges for logistics and transportation. As a result, many discarded blades end up in landfills, exacerbating the global waste problem. Researchers and industry experts recognize the importance of developing more sustainable solutions, and for this purpose, researchers have been working tirelessly to develop new methods for recycling wind turbine blades.

[0003] Currently, the degradation and recycling methods for wind turbine blade composites mainly include mechanical recycling, thermal recycling, and chemical recycling. The mechanical recycling method cuts waste fibers into shorter fibers or grinds them into fine powders for secondary use, but this method inhibits the performance of carbon fiber or glass fiber and has low utilization efficiency. Thermal recycling methods include pyrolysis, fluidized bed, and microwave pyrolysis, which can degrade the resin at high temperatures, but also face many problems such as high energy consumption, generation of gas by-products, and poor fiber strength retention. The chemical recycling method uses chemical reagents to strip fibers, such as carbon fibers, from the resin matrix, and the recovered carbon fibers have higher value than those obtained by the mechanical recycling method. The most commonly used chemical recycling methods are the supercritical fluid method and the solvent method. The supercritical fluid method has the characteristic of efficiently degrading the resin matrix, but its degradation process conditions of high temperature and high pressure are extremely demanding.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The main object of the present invention is to provide a compounding aid for recycling wind turbine blade composites, a recycling method, and a recycling system, so as to solve the problems of low fiber utilization rate, high energy consumption, or harsh process conditions in the degradation and recycling of wind turbine blade composites by mechanical recycling, thermal recycling, and chemical recycling methods in the prior art.

[0006] To achieve the above object, according to one aspect of the present invention, a compounding aid for wind turbine blade composites is provided. The compounding aid includes component A and component B, and the mass ratio of the two is 1:5 to 5:1. Among them, component A is an organic alcohol, and component B is an organic acid.

[0007] Further, component A includes at least one of benzyl alcohol, ethylene glycol, n-propanol, isopropanol, and n-butanol; and / or, component B includes at least one of salicylic acid, fumaric acid, tartaric acid, citric acid, succinic acid, lauric acid, acetic acid, lactic acid, and oxalic acid.

[0008] Further, component A is a mixed alcohol of ethylene glycol and n-propanol, and the mass ratio of the two is 1:1 to 3:1; and / or, component B is a mixed acid of tartaric acid and oxalic acid, and the mass ratio of the two is 1:5 to 1:10.

[0009] To achieve the above object, according to another aspect of the present invention, there is also provided a method for recycling the above wind turbine blade composite material, which uses the compounding auxiliary agent provided in the above first aspect for recycling treatment. The recycling method includes: Step S1, crushing the wind turbine blade composite material to obtain composite material particles, and the particle size of the composite material particles is ≤ 20 mm; Step S2, mixing the composite material particles with component A for a primary treatment to obtain an organic alcohol treatment product; Step S3, mixing the organic alcohol treatment product with component B for a secondary treatment to obtain a recycled product.

[0010] Further, in step S2, component A is first dispersed in water to form an aqueous solution of component A, and then the composite material particles are mixed with the aqueous solution of component A for a primary treatment. Among them, the molar concentration of the aqueous solution of component A is 0.1 to 1 mol / L, and the solid-liquid ratio of the composite material particles to the aqueous solution of component A is 1 g: 10 to 20 mL; and / or, the temperature of the primary treatment is 20 to 100 °C, and the time is 0.5 to 5 h.

[0011] Further, step S2 includes: Step S21, mixing the composite material particles with the aqueous solution of component A for a primary treatment to obtain an organic alcohol treatment reaction solution; Step S22, performing solid-liquid separation on the organic alcohol treatment reaction solution to obtain an organic alcohol treatment product.

[0012] Further, in step S3, component B is first dispersed in water to form an aqueous solution of component B, and then the organic alcohol treatment product is mixed with the aqueous solution of component B for a secondary treatment. Among them, the molar concentration of the aqueous solution of component B is 0.1 to 5 mol / L, and the solid-liquid ratio of the acid treatment product to the aqueous solution of component B is 1 g: 20 to 50 mL; and / or, the temperature of the secondary treatment is 20 to 100 °C, the pressure is 0 to 10 MPa, and the time is 0.5 to 6 h.

[0013] Further, step S3 includes: Step S31, mixing the organic alcohol treatment product with the aqueous solution of component B for a secondary treatment to obtain a recycling treatment solution; Step S32, performing solid-liquid separation and drying on the recycling treatment solution in sequence to obtain a recycled product.

[0014] Further, the composite material of the wind turbine blade is a composite material of fiber and resin. Among them, the fiber includes at least one of glass fiber or carbon fiber, and the resin includes at least one of epoxy resin, phenolic resin and polysilazane.

[0015] According to another aspect of the present invention, there is also provided a recycling system for the composite material of the wind turbine blade. This system is used to carry out the recycling method provided in the second aspect above. The recycling system includes a primary treatment unit, a secondary treatment unit and a product collection unit. Among them, the primary treatment unit includes a primary treatment device and an oil separation device. The primary treatment device includes a first feed port, a first solid outlet and a first liquid outlet. The first liquid outlet is connected to the oil separation device, and the first feed port is used to add composite material particles. The secondary treatment unit includes a secondary treatment device. The secondary treatment device includes a second feed port, a second solid outlet and a second liquid outlet. The second feed port is connected to the first solid outlet. The product collection unit includes a product collection device. The product collection device includes a third feed port and a third solid outlet. The third feed port is connected to the second solid outlet, and the third solid outlet is used to discharge the recycled product.

[0016] Applying the technical solution of the present application, the compounding aid for the composite material of the wind turbine blade provided by the present application recycles the composite material of the wind turbine blade through the mutual cooperation of the A component of the organic alcohol and the B component of the organic acid with a specific mass ratio. It not only has a simple process, low energy consumption, is green and environmentally friendly, but also has a high degradation rate. The degree of damage to the fibers in the recycled product is small, the loss rate is low, the recovery rate ≥ 95%, and the purity is high, with extremely little resin residue, which is more conducive to the recycling of the fibers in the recycled product. Detailed Embodiments

[0017] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0018] As analyzed in the background technology of the present application, at present, the degradation and recycling methods of the composite material of the wind turbine blade are mainly mechanical recycling method, thermal recycling method and chemical recycling method. The mechanical recycling method inhibits the high performance of carbon fiber or glass fiber and has a low utilization efficiency. The thermal recycling method requires the degradation of the resin at high temperature, facing problems such as high energy consumption, generation of gas by-products and poor fiber strength retention. The chemical recycling method requires the separation of the fiber from the resin matrix. Although the most commonly used supercritical method can efficiently degrade the resin matrix, the degradation process conditions of high temperature and high pressure are extremely harsh. To solve this problem, the present application provides a compounding aid for recycling the composite material of the wind turbine blade, a recycling method and a recycling system.

[0019] In the first typical embodiment of the present application, a compounding aid for the recycling of wind turbine blade composites is provided. The compounding aid includes component A and component B, and the mass ratio of the two is 1:5 to 5:1; wherein, component A is an organic alcohol and component B is an organic acid.

[0020] Typically but not restrictively, in the compounding aid, the mass ratio of component A to component B is, for example, 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1 or a range value composed of any two values.

[0021] The compounding aid for wind turbine blade composites provided by the present application recycles wind turbine blade composites through the mutual cooperation of component A of organic alcohol and component B of organic acid with a specific mass ratio. It not only has a simple process, low energy consumption, is green and environmentally friendly, but also has a high degradation rate. The degree of damage to the fibers in the recovered product is small, the loss rate is low, the recovery rate is ≥ 95%, and the purity is high, with extremely little resin residue, which is more conducive to the recycling of the fibers in the recovered product.

[0022] [Component A]

[0023] The organic alcohol used as component A in the present application includes, but is not limited to, any one or more of benzyl alcohol, ethylene glycol, n-propanol, isopropanol, and n-butanol to form a mixed organic alcohol.

[0024] To further improve the degradation rate of wind turbine blade composites, it is preferred that component A is a mixed alcohol of ethylene glycol and n-propanol, and the mass ratio of the two is 1:1 to 3:1, such as 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5 or a range value composed of any two values.

[0025] [Component B]

[0026] The organic acid used as component B in the present application includes, but is not limited to, any one or more of salicylic acid, fumaric acid, tartaric acid, citric acid, succinic acid, lauric acid, acetic acid, lactic acid, and oxalic acid to form a mixed organic acid.

[0027] To further improve the degradation rate of wind turbine blade composites, it is preferred that component B is a mixed acid of tartaric acid and oxalic acid, and the mass ratio of the two is 1:5 to 1:10; such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or a range value composed of any two values.

[0028] In the second typical embodiment of the present application, a method for recycling wind turbine blade composite materials is also provided. The composite additives provided in the first typical embodiment are used to recycle the wind turbine blade composite materials. The recycling method includes: Step S1, crushing the wind turbine blade composite materials to obtain composite material particles with a particle size of ≤20 mm; Step S2, mixing the composite material particles with component A for primary treatment to obtain an organic alcohol treatment product; Step S3, mixing the organic alcohol treatment product with component B for secondary treatment to obtain a recycled product.

[0029] The recycling method of the wind turbine blade composite material provided in the present application uses organic alcohol for primary treatment and organic acid for secondary treatment, enabling the organic alcohol and organic acid to synergize with each other. Not only are the raw materials easily obtainable, the cost low, the process simple, the energy consumption low, and it is green and environmentally friendly, but also the degradation rate of the wind turbine blade composite material is high. The surface of the fibers in the obtained recycled product is basically intact, the fiber strength retention rate is high, the resin residue is extremely small, the fiber purity is high, and the loss rate is low, making it more conducive to recycling and promoting the high-speed development of the circular economy of wind turbine blade composite materials.

[0030] In the present application, in Step S1, crushing the wind turbine blade composite materials into particulate form makes it more convenient to perform infiltration and degradation treatment with organic alcohol.

[0031] In the above Step S2, in order to further improve the primary treatment efficiency and the degradation efficiency of the wind turbine blade composite material particles, it is preferred to first disperse component A in water to form an aqueous solution of component A, and then mix the composite material particles with the aqueous solution of component A for primary treatment. Among them, the molar concentration of the aqueous solution of component A is 0.1 - 1 mol / L (such as 0.1 mol / L, 0.2, 0.3, 0.5, 0.8, 1.0 mol / L), and the solid-liquid ratio of the composite material particles to the aqueous solution of component A is 1 g:10 - 20 mL, such as 1 g:10 mL, 1 g:12 mL, 1 g:15 mL, 1 g:18 mL, 1 g:20 mL or a range value composed of any two numerical values.

[0032] In order to further improve the degradation rate of the wind turbine blade composite material particles, it is preferred that the temperature of the primary treatment is 20 - 100 °C and the time is 0.5 - 5 h. The reaction conditions of the above primary treatment are mild, the heat treatment temperature is 20 - 100 °C, which greatly reduces the degradation energy consumption, the process is simple, the reaction conditions are easy to control, no additional pressure is required, it is safe and reliable, and it is green and environmentally friendly during the primary treatment process and is easy to be applied industrially.

[0033] Typically but not restrictively, the temperature of the primary treatment is, for example, 20, 30, 40, 50, 60, 80, 100 °C or a range value composed of any two values, and the time of the primary treatment is, for example, 30 min, 45 min, 1 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h or a range value composed of any two values.

[0034] In some specific embodiments, step S2 includes: step S21, mixing the composite material particles with an aqueous solution of component A for a primary treatment to obtain an organic alcohol treatment reaction solution; step S22, performing solid-liquid separation on the organic alcohol treatment reaction solution to obtain an organic alcohol treatment product. In step S22, it is preferred to wash with distilled water until neutral after solid-liquid separation.

[0035] To further improve the degradation efficiency of the organic acid on the alcohol treatment product during the secondary treatment, step S3 is preferably carried out by first dispersing component B in water to form an aqueous solution of component B, and then mixing the organic alcohol treatment product with the aqueous solution of component B for a secondary treatment, wherein the molar concentration of the aqueous solution of component B is 0.1 - 5 mol / L, and the solid-liquid ratio of the organic alcohol treatment product to component B is 1 g:20 - 50 mL; such as 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:50 mL or a range value composed of any two values.

[0036] To further improve the efficiency of the secondary treatment, it is preferred that the temperature of the secondary treatment is 20 - 100 °C, the pressure is 0 - 10 MPa, and the time is 0.5 - 6 h. The temperature of this secondary treatment is 20 - 100 °C, which greatly reduces the degradation energy consumption, and the process is simple, the reaction conditions are easy to control, no additional pressure is required, it is safe and reliable, and it is green and environmentally friendly during the secondary treatment and is easy to be applied industrially.

[0037] Typically but not restrictively, the temperature of the secondary treatment is, for example, 20, 30, 40, 50, 60, 80, 100 °C or a range value composed of any two values, the time of the secondary treatment is, for example, 30 min, 45 min, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h or a range value composed of any two values; the pressure is, for example, 0 MPa, 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 5 MPa, 8 MPa or a range value composed of any two values.

[0038] In some specific embodiments, step S3 is carried out according to the following steps: step S31, mixing the organic alcohol treatment product with the aqueous solution of component B for a secondary treatment to obtain a recovery treatment solution, and step S32, performing solid-liquid separation and drying on the recovery treatment solution in sequence to obtain a recovery product.

[0039] It should be noted that in this application, the composite material of the wind turbine blade is a composite material of fiber and resin. Among them, the fiber includes, but is not limited to, any one or a mixture of more than one of glass fiber or carbon fiber, and the resin includes any one or a mixed resin of epoxy resin, phenolic resin, and polysilazane.

[0040] In this application, the recycled product mainly refers to the fiber, and the degraded resin can also be recycled.

[0041] In the third typical embodiment of this application, a recycling system for the composite material of the wind turbine blade is also provided. This recycling system is used to carry out the recycling method of the composite material of the wind turbine blade provided in the second typical embodiment. This recycling system includes:

[0042] A primary treatment unit, which includes a primary treatment device and an oil separation device. The primary treatment device includes a first feed port, a first solid outlet, and a first liquid outlet. The first liquid outlet is connected to the oil separation device, and the first feed port is used to add composite material particles; the oil separation device is used to separate oil from the liquid after primary treatment;

[0043] A secondary treatment unit, which includes a secondary treatment device. The secondary treatment device includes a second feed port, a second solid outlet, and a second liquid outlet. Among them, the second feed port is connected to the first solid outlet;

[0044] A product collection unit, which includes a product collection device. The product collection device includes a third feed port and a third solid outlet. The third feed port is connected to the second solid outlet, and the third solid outlet is used to discharge the recycled product (fiber).

[0045] Compared with the prior art, this application has the following advantages:

[0046] 1. The recycling method provided in this application uses the solvothermal method, which mainly takes the advantages of the solvent method. After mixing the solvent, an optional catalyst, and the composite material particles of the wind turbine blade and then performing heat treatment, fibers with basically no defects on the surface and a fiber strength retention rate as high as 98.5% can be obtained. Moreover, in this application, the degradation rate of the resin is as high as 99.2%, and the fiber recovery rate reaches 95%, making the fibers obtained by recycling in this application have a clean surface and extremely little resin residue.

[0047] 2. This application uses the solvothermal method to recycle fibers. The reaction conditions are mild, and the heat treatment temperature only needs to be 20 - 100 °C, greatly reducing the degradation energy consumption of the composite material particles of the wind turbine blade. Moreover, the process of this invention is simple, the reaction conditions are easy to control, no additional pressure is required, it is safe and reliable. In addition, this application does not release toxic gases, the degradation and recycling process is green and environmentally friendly, and the raw materials are easy to obtain, the cost is low, and it is easy to be applied industrially.

[0048] 3. Compared with existing recycling technologies, the present invention adopts a combination of alcohol and acid, which not only significantly reduces the degree of damage to fibers and the loss rate is significantly reduced, but also the degradation rate is increased. The operation process of this application is simple, the requirements for operating equipment are low, and it is suitable for industrialized scale-up production. The compound auxiliary agent used is inexpensive and easy to obtain, which can accelerate the degradation process of the resin matrix, enable the resin matrix to be fully degraded. Compared with the existing recycling technologies for wind turbine blade composites, the recycling temperature is significantly reduced, the recycling time is shortened, the operating conditions are mild, and the problem of difficult interlayer peeling of composite laminates is solved. It avoids the uneven performance and quality caused by the difference in the reaction time between the outer layer fibers and the inner layer fibers, and ensures the product quality when recycling fibers. Therefore, this application has the advantages of high efficiency, convenience, economy, and good product quality, and has broad market prospects.

[0049] 4. The degradation mechanism of the present invention for wind turbine blade composites with a matrix of composites such as glass fiber / carbon fiber - epoxy resin - polyetheramine (polyetheramine or a polyetheramine compound as the curing agent for epoxy resin) is as follows:

[0050] (1) First, the composite material particles are treated once with organic alcohol and then treated twice with organic acid to obtain a recycled treatment liquid;

[0051] (2) The proportion of the organic alcohol that can be recycled and used in the supernatant is as high as over 95 wt%, and the loss rate is less than 5%;

[0052] (3) The glass fiber / carbon fiber and the gelled substances after the degradation of epoxy resin and polyetheramine are in the lower layer. By successively washing with common solvents such as acetone and pure water, the glass fiber / carbon fiber can be separated;

[0053] (4) Filter the remaining gelled substances to successively recycle resins such as epoxy resin and polyetheramine.

[0054] During the degradation and recycling process of composite material particles, component A in the compounding auxiliary swells and enters the polymer matrix network; under the action of optional accelerators such as ZnCl2 and Zn(AC)2, organic alcohols (especially composite organic alcohols) cause the epoxy cured matrix to swell, and then the hydroxyl groups in composites such as epoxy cured products (epoxy-polyetheramine crosslinked network) undergo esterification reactions under the action of organic acids (especially composite organic acids). This reaction can destroy part of the resin network structure. The organic acid can also react with the residual tertiary amine structure in the epoxy cured product to form an amide structure, which will cut off the resin network structure and reduce the crosslinking degree; the carboxyl protons in the organic acid can react with the oxygen atoms of the ether bonds in the epoxy structure, causing the ether bonds to break to generate carbocations and corresponding alcohol anions, significantly reducing the crosslinking density of the epoxy cured product. Under the above mechanism, under the action of components A and B, the crosslinking density is reduced and accompanied by the breakage of ether bonds, thus realizing the gradual disintegration of the crosslinked network.

[0055] In some other embodiments, the recycling system further includes a feeding device connected to the first feeding port to facilitate adding composite material particles into the primary treatment device for primary treatment.

[0056] In some other embodiments, in order to recycle the resin in the wind turbine blade composite material, preferably, the recycling system further includes a resin collection device and a filtering device, and the product collection device further includes a third liquid outlet. The third liquid outlet and the liquid outlet of the oil separation device are respectively connected to the inlet of the filtering device, and the outlet of the filtering device is connected to the inlet of the resin collection device, so as to recycle the resin through the resin collection device.

[0057] The beneficial effects of the present application will be further described below in conjunction with examples and comparative examples.

[0058] Example 1

[0059] This example provides a compounding auxiliary for recycling wind turbine blade composite materials, which is compounded by component A and component B, and the mass ratio of the two is 1:2; wherein component A is ethylene glycol and component B is oxalic acid.

[0060] Example 2

[0061] This example provides a compounding auxiliary for recycling wind turbine blade composite materials, which is compounded by component A and component B, and the mass ratio of the two is 2.5:1; wherein component A is propanol and component B is tartaric acid.

[0062] Example 3

[0063] The difference between this example and Example 1 is that the mass ratio of Component A to Component B is 1:2.5. Component A is a mixed alcohol of ethylene glycol and propanol, and the mass ratio of the two is 2:1; Component B is a mixed acid of oxalic acid and tartaric acid, and the mass ratio of the two is 1:7.

[0064] Example 4

[0065] The difference between this example and Example 3 is that in Component A, the mass ratio of ethylene glycol to propanol is 1:1; in Component B, the mass ratio of oxalic acid to tartaric acid is 1:5.

[0066] Example 5

[0067] The difference between this example and Example 3 is that in Component A, the mass ratio of ethylene glycol to propanol is 3:1, and in Component B, the mass ratio of oxalic acid to tartaric acid is 1:10.

[0068] Example 6

[0069] The difference between this example and Example 3 is that in Component B, the mass ratio of oxalic acid to tartaric acid is 1:2.

[0070] Example 7

[0071] The difference between this example and Example 3 is that in Component A, the mass ratio of ethylene glycol to propanol is 5:1.

[0072] Example 8

[0073] The difference between this example and Example 3 is that the mass ratio of Component B to Component A is 1:5.

[0074] Example 9

[0075] The difference between this example and Example 3 is that the mass ratio of Component B to Component A is 5:1.

[0076] Comparative Example 1

[0077] The difference between this comparative example and Example 3 is that the mass ratio of Component B to Component A is 1:10.

[0078] Comparative Example 2

[0079] The difference between this comparative example and Example 3 is that the mass ratio of Component B to Component A is 10:1.

[0080] Comparative Example 3

[0081] The difference between this comparative example and Example 3 is that it does not contain Component A.

[0082] Comparative Example 4

[0083] The difference between this comparative example and Example 3 is that it does not contain Component B.

[0084] Example 10

[0085] This example provides a method for recycling wind turbine blade composites, which uses the compounding aid provided in Example 1 for recycling, and specifically includes the following steps:

[0086] A. Cut the wind turbine blade composite material mainly composed of glass fiber / epoxy resin to obtain composite material particles with a particle size of 15 mm;

[0087] B. Disperse Component A in water to form an aqueous solution of Component A with a molar concentration of 0.5 mol / L. Mix the composite material particles and the aqueous solution of Component A at a solid-liquid ratio of 1 g:15 mL, place them in an 80°C water bath together, and perform one treatment by shaking for 2 hours to obtain an organic alcohol treatment reaction solution. Take out the solid product in the organic alcohol treatment reaction solution, cool it, and wash the solid product with distilled water until the washing liquid is neutral to obtain an organic alcohol treatment product;

[0088] C. Disperse Component B in water to form an aqueous solution of Component B with a molar concentration of 1 mol / L. Pass the organic alcohol treatment product into a sealed reactor and mix it with the aqueous solution of Component B for a second treatment. The temperature of the second treatment is 80°C, the pressure in the container is 2 MPa, and the treatment time is 45 minutes to obtain a recycled treatment solution; wherein, the solid-liquid ratio of the organic alcohol treatment product to the aqueous solution of Component B is 1 g:35 mL.

[0089] D. Perform vacuum filtration and spray drying on the recycled treatment solution to finally obtain a recycled product.

[0090] Example 11

[0091] This example provides a method for recycling wind turbine blade composites, which uses the compounding aid provided in Example 2 for recycling, and specifically includes the following steps:

[0092] A. Cut the wind turbine blade composite material mainly composed of carbon fiber / epoxy resin / polysilazane to obtain composite material particles with a particle size of 12 mm;

[0093] B. Mix the composite material particles and the aqueous solution of Component A (molar concentration of 1 mol / L) at a solid-liquid ratio of 1 g:10 mL, place them in a 60°C water bath together, and perform a second treatment by shaking for 4 hours to obtain an organic alcohol treatment reaction solution. Take out the solid product in the organic alcohol treatment reaction solution, cool it, and wash the solid product with distilled water until the washing liquid is neutral to obtain an organic alcohol treatment product;

[0094] C. Feed the organic alcohol treated product into a sealed reactor, and perform secondary treatment using an aqueous solution of component B (molar concentration: 0.5 mol / L). The temperature for secondary treatment is 70 °C, the container pressure is 4 MPa, and the treatment time is 60 minutes to obtain a recycled treatment liquid. Among them, the solid-liquid ratio of the organic alcohol treated product to the aqueous solution of component B is 1 g:50 mL;

[0095] D. Perform vacuum filtration and spray drying on the recycled treatment liquid to finally obtain a recycled product.

[0096] Examples 12 - 18

[0097] Examples 12 - 18 respectively provide a method for recycling wind turbine blade composite materials. The difference from Example 10 is that the compounding aids provided in Examples 3 - 9 are used to replace the compounding aids in Example 1 for the recycling treatment of wind turbine blade composite materials.

[0098] Example 19

[0099] The difference between this example and Example 12 is that in step B, the solid-liquid ratio of the composite material particles to the aqueous solution of component A is 1 g:20 mL; in step C, the solid-liquid ratio of the organic alcohol treated product to component B is 1 g:20 mL.

[0100] Example 20

[0101] The difference between this example and Example 12 is that in step B, the temperature for primary treatment is 20 °C and the oscillation time is 5 h. In step C, the temperature for secondary treatment is 20 °C and the time is 6 h.

[0102] Example 21

[0103] The difference between this example and Example 12 is that in step B, the temperature for primary treatment is 100 °C and the oscillation time is 1 h. In step C, the temperature for secondary treatment is 100 °C and the time is 30 min.

[0104] Comparative Examples 5 - 8

[0105] Comparative Examples 5 - 8 respectively provide a method for recycling wind turbine blade composite materials. The difference from Example 12 is that the compounding aids provided in Comparative Examples 1 - 4 are used to replace the compounding aids in Example 3.

[0106] Test Examples

[0107] The recovered products provided in Examples 10 - 21 and Comparative Examples 5 - 8 were tested for fiber purity and fiber strength retention rate (actually, the strength of the "fiber and its residual resin" mixture / the strength of the fiber without recycling treatment), and at the same time, the fiber recovery rate was calculated based on the mass of the recovered product and the mass of the fiber in the wind turbine blade composite material. The results are shown in Table 1 below.

[0108] Among them, (1) The fiber purity was determined by the TGA thermogravimetric method, which specifically included the following steps: Take a recovered fiber sample with a mass of m1, and use TGA to heat it to 500 °C in an air atmosphere, record the sample weight m2, and calculate the purity according to m2 / m1;

[0109] (2) The strength of the fiber and its residual resin mixture was determined with reference to GB / T 3362 - 2017;

[0110] (3) The strength of the fiber without recycling treatment was calculated according to the strength of the raw yarn, and the strength of the raw yarn was determined with reference to GB / T 3362 - 2017.

[0111] Table 1

[0112]

[0113]

[0114] From the above description, it can be seen that the above embodiments of the present invention have achieved the following technical effects: By applying the technical solution of the present application, the compounding aid for wind turbine blade composite materials provided by the present application recovers the wind turbine blade composite material through the mutual cooperation of component A of organic alcohol and component B of organic acid with a specific mass ratio. It not only has a simple process, low energy consumption, is green and environmentally friendly, but also has a high degradation rate. The fiber in the recovered product has little damage, low loss rate, the recovery rate ≥ 95%, high purity, and extremely little resin residue, which is more conducive to the recycling of the fiber in the recovered product.

[0115] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for recycling composite materials of wind turbine blades, characterized in that, The recycling method includes: Step S1: Crushing the wind turbine blade composite material to obtain composite material particles with a particle size of ≤ 20 mm; Step S2: Mixing the composite material particles with component A for primary treatment to obtain an organic alcohol treatment product; Step S3: Mixing the organic alcohol treatment product with component B for secondary treatment to obtain a recycled product; The mass ratio of component A to component B is 1:5 to 5:1, where component A is an organic alcohol and component B is an organic acid; Component A is a mixed alcohol of ethylene glycol and n-propanol, and the mass ratio of the two is 1:1 to 3:1; Component B is a mixed acid of tartaric acid and oxalic acid, and the mass ratio of the two is 1:5 to 1:10; In step S2, first disperse component A in water to form an aqueous solution of component A, and then mix the composite material particles with the aqueous solution of component A for the primary treatment. The molar concentration of the aqueous solution of component A is 0.1 to 1 mol / L, and the solid-liquid ratio of the composite material particles to the aqueous solution of component A is 1 g:10 to 20 mL; the temperature of the primary treatment is 20 to 100 °C, and the time is 0.5 to 5 h; In step S3, first disperse component B in water to form an aqueous solution of component B, and then mix the organic alcohol treatment product with the aqueous solution of component B for the secondary treatment. The molar concentration of the aqueous solution of component B is 0.1 to 5 mol / L, and the solid-liquid ratio of the organic alcohol treatment product to the aqueous solution of component B is 1 g:20 to 50 mL; the temperature of the secondary treatment is 20 to 100 °C, the pressure is 0 to 10 MPa, and the time is 0.5 to 6 h.

2. The recovery method according to claim 1, wherein Step S2 includes: Step S21: Mixing the composite material particles with the aqueous solution of component A for the primary treatment to obtain an organic alcohol treatment reaction solution; Step S22: Separating the solid and liquid of the organic alcohol treatment reaction solution to obtain the organic alcohol treatment product.

3. The recovery method according to claim 1, wherein Step S3 includes: Step S31: Mixing the organic alcohol treatment product with the aqueous solution of component B for secondary treatment to obtain a recycling treatment solution; Step S32: Separating the solid and liquid and drying the recycling treatment solution in sequence to obtain the recycled product.

4. The recovery method according to any one of claims 1 to 3, characterized in that The wind turbine blade composite material is a composite material of fiber and resin. The fiber includes at least one of glass fiber or carbon fiber, and the resin includes at least one of epoxy resin, phenolic resin, and polysilazane.

5. A wind turbine blade composite material recycling system, characterized in that, The recycling system is used to perform the recycling method according to any one of claims 1 to 4. The recycling system includes: A primary treatment unit. The primary treatment unit includes a primary treatment device and an oil stain separation device. The primary treatment device includes a first feed port, a first solid outlet, and a first liquid outlet. The first liquid outlet is connected to the oil stain separation device, and the first feed port is used to add the composite material particles; Secondary treatment unit, the secondary treatment unit includes a secondary treatment device, the secondary treatment device includes a second feed inlet, a second solid outlet and a second liquid outlet, and the second feed inlet is connected to the first solid outlet; Product collection unit, the product collection unit includes a product collection device, the product collection device includes a third feed inlet and a third solid outlet, the third feed inlet is connected to the second solid outlet, and the third solid outlet is used to discharge the recovered product.

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