Method for degrading retired wind power blade material by using composite solvent

Abstract

The invention provides a method for degrading a retired wind power blade material by using a composite solvent, and belongs to the technical field of solid waste recycling. The method comprises the following steps: physically crushing the retired wind power blade to obtain a sample; mixing the sample with an organic solvent and an ionic liquid for reaction; the ionic liquid is imidazole salt ionic liquid or pyridine salt ionic liquid. According to the method disclosed by the invention, the retired wind power blade material is degraded by adopting the ionic liquid-organic solvent, so that oligomer or micromolecular monomer substances which are easy to separate are generated, and different components are effectively separated. After the reaction is finished, a glass fiber, balsa wood and rigid foam mixed material can be recovered and obtained, the mixed material can be used as a filler, a thermosetting resin degradation product can be converted into a useful chemical product and has high utilization value, and a catalyst is easy to recycle and reuse.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste recycling, and in particular to a method for degrading retired wind turbine blade materials using a composite solvent. Background Art

[0002] Wind power is a renewable, clean energy source. Currently, wind turbine blades are mostly manufactured using fiber-reinforced thermosetting resin-based composites, with unsaturated polyester resin and epoxy resin being the preferred thermosetting resins. These composites offer advantages such as high specific strength, excellent fatigue resistance, corrosion resistance, and weather resistance, resulting in a service life of 20 to 25 years. Thermosetting resins readily cross-link with various curing agents to form a cured product with a three-dimensional network structure. The cured thermosetting resins exhibit excellent electrical insulation, heat resistance, cold resistance, and corrosion resistance. They are widely used in the power, chemical, energy, building materials, transportation, machinery, and hydraulic industries, primarily as adhesives, corrosion-resistant coatings, and electrical insulation materials. Traditional methods for recycling and repurposing retired wind turbine blades include open-air stacking, landfilling, or incineration. However, open-air stacking and landfilling require significant space and release toxic substances that can contaminate soil and groundwater systems. Direct incineration, on the other hand, produces significant amounts of heat, toxic gases, and smoke. At present, mechanical recycling, pyrolysis and chemical recycling are the most commonly used recycling technologies.

[0003] The mechanical recycling method is a recycling method in which the composite materials in the wind turbine blades are chopped, ground or milled into smaller pieces, and then ground into powdered materials. This method is simple to produce, but if it is not modified, the economic benefits are low and the environmental impact during processing will be increased. The pyrolysis method is to degrade the resin-based composite materials into two parts, the matrix and the reinforcement, to achieve the processing of the composite materials. This method does not use chemical agents, but high temperatures will affect the tensile strength of the material and may release harmful gases. The chemical recovery method is to use chemical methods to cut the chemical bonds in the composite materials under specific conditions, thereby achieving the separation of the resin and the fiber in the composite materials to achieve the purpose of recycling. This method can effectively recycle resin-based composite materials, but the existing technology uses strong alkaline solvents and has the disadvantage of harsh reaction conditions. Summary of the Invention

[0004] In view of the defects of the existing technology, the purpose of the present invention is to provide a method for degrading retired wind turbine blade materials using a composite solvent. The method has the advantages of mild reaction conditions, simple recovery process, high utilization rate of degradation products, and little impact on the environment.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for degrading retired wind turbine blade materials using a composite solvent comprises the following steps:

[0007] Physically crush the retired wind turbine blades to obtain samples;

[0008] mixing the sample with an organic solvent and an ionic liquid and reacting the mixture;

[0009] The ionic liquid is an imidazolium salt ionic liquid or a pyridinium salt ionic liquid;

[0010] The imidazolium salt ionic liquid is at least one of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4), 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), 1-butyl-3-methylimidazolium bromide ([Bmim]Br), 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim]BF4), 1-butyl-2,3-dimethylimidazolium hydroxide ([Bdmim]OH), 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]), and 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH);

[0011] The pyridinium salt ionic liquid is at least one of 1-butyl-4-methylpyridinium chloride ([BMPy]Cl), 1-butyl-4-methylpyridinium bromide ([BMPy]Br), 1-ethyl-3-methylpyridinium hydroxide ([EMPy]OH), 1-hexyl-3-methylpyridinium chloride ([HMPy]Cl) and 1-butyl-3-methylpyridinium diethyl phosphate ([BMPy][(DEP]).

[0012] In some embodiments of the present invention, the decommissioned wind turbine blades include a fiber-reinforced thermosetting resin-based composite material. The decommissioned wind turbine blades of the present invention are derived from discarded wind turbine blades from the wind power generation industry and are typically composed of glass fiber (51%), cured epoxy resin (32%), rigid foam, balsa wood (7.5%), auxiliary materials, and an adhesive-doped mixed material (9.5%).

[0013] In some embodiments of the present invention, the organic solvent is a polar aprotic solvent.

[0014] In some embodiments of the present invention, the polar aprotic solvent is at least one of dimethyl sulfoxide (DMSO), 1,3-dimethyl-2-imidazolidinone (DMI), dimethylacetamide (DMAc), 4-dimethylaminopyridine (DMAP), N-methylpyrrolidone (NMP) and dimethylformamide (DMF).

[0015] In some embodiments of the present invention, the mass ratio of the ionic liquid to the organic solvent is (0.07-1):1.

[0016] In some embodiments of the present invention, the mass ratio of the ionic liquid to the organic solvent is (0.2-0.5):1.

[0017] In some embodiments of the present invention, the liquid-to-solid ratio of the total volume of the ionic liquid and the organic solvent to the sample is 5 to 100:1.

[0018] In some embodiments of the present invention, the liquid-to-solid ratio of the total volume of the ionic liquid and the organic solvent to the sample is 5 to 50:1.

[0019] In some embodiments of the present invention, the liquid-to-solid ratio of the total volume of the ionic liquid and the organic solvent to the sample is 10 to 20:1.

[0020] In the present invention, a too low mass ratio of ionic liquid to organic solvent will result in reduced decomposition efficiency, while a too high mass ratio will increase the viscosity of the system and increase the cost of the system. Only when the parameters are within the range described in the present invention can the degradation effect of the system be best.

[0021] In some embodiments of the present invention, the reaction temperature is 110-250° C., the reaction time is 1-24 h, and the pressure is 1-10 MPa.

[0022] In some embodiments of the present invention, the reaction temperature is 150-200° C., the reaction time is 5-10 h, and the pressure is 1-10 MPa.

[0023] The present invention discloses the following technical effects:

[0024] The imidazolium or pyridinium salt ionic liquids used in the degradation process of fiber-reinforced thermosetting resin-based composite materials in the present invention have good thermal stability and excellent catalytic degradation of thermosetting resins, generating easily separable oligomers or small-molecule monomers without damaging other components in the material, thereby effectively separating the different components. Furthermore, the experimental conditions are more moderate, and the lower heating temperature reduces the volatilization of the organic solvent, resulting in a lower pressure in the reaction system. After the reaction, the glass fiber, balsa wood, and rigid foam mixed material can be recovered and used as a filler. The thermosetting resin degradation products can be converted into useful chemical products with high utilization value, and the catalyst is easily recyclable.

[0025] The invention adopts imidazole salt or pyridinium salt ionic liquid to degrade fiber-reinforced thermosetting resin-based composite material, and the degradation rate is high, reaching more than 73%. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0028] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0029] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0030] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0031] The present invention provides a method for degrading retired wind turbine blade materials using a composite solvent, comprising the following steps:

[0032] (1) Physically crushing retired wind turbine blades containing fiber-reinforced thermosetting resin-based composite materials to obtain samples;

[0033] (2) mixing the sample with an organic solvent and an ionic liquid and reacting the mixture;

[0034] (3) After the reaction is completed, a solid-liquid mixture is obtained, the solid-liquid mixture is washed with pure water and then filtered, the collected solid phase product is dried and weighed, and the degradation rate of the organic component is calculated.

[0035] The ionic liquid is an imidazolium salt ionic liquid or a pyridinium salt ionic liquid;

[0036] The imidazolium salt ionic liquid is at least one of 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium 1,3-dimethylimidazolium hydroxide, 1-butyl-3-methylimidazolium bromide, 1-butyl-2,3-dimethylimidazolium hydroxide and 1-butyl-3-ethylimidazolium borate;

[0037] The pyridinium salt ionic liquid is at least one of 1-butyl-4-methylpyridinium chloride, 1-butyl-4-methylpyridinium bromide, 1-ethyl-3-methylpyridinium hydroxide, 1-hexyl-3-methylpyridinium chloride and 1-butyl-3-methylpyridinium diethyl phosphate.

[0038] The calculation formula of the degradation rate of the organic component (ie thermosetting resin) is expressed as: η = (m1-m2) / rm1×100%

[0039] Where: η—degradation rate of organic components, %;

[0040] m1—initial weight of retired wind turbine blade block sample, g;

[0041] m2—mass of solid phase product after reaction, g;

[0042] r—The proportion of organic components in retired wind turbine blade materials is 32%.

[0043] Unless otherwise specified, the technical solutions described in the present invention are all conventional solutions in the field, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0044] The composition and content of the retired wind turbine blade material in the embodiment are as follows: glass fiber accounts for 51%, epoxy resin accounts for 32%, core materials include rigid foam and balsa wood, accounting for 7.5%, and other auxiliary materials and adhesives account for 9.5%.

[0045] In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

[0046] Example 1

[0047] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0048] (2) Take an appropriate amount of cut sample, weigh it (mass is m1 = 30 g), and put it into the reactor. Mix [Bmim]BF4, DMI and the sample according to the ratio of [Bmim]BF4 (g): DMI (g) = 0.32:1 and the liquid-to-solid ratio of 20 mL / g. Set the temperature of the reactor to 200 ° C, the holding time to 7 h, the pressure to 7 MPa, and the stirring rate to 130 RPM. After the reaction is completed, cool down and reduce the pressure to obtain a solid-liquid mixture.

[0049] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 20.64 g). The calculated degradation rate of the organic component was 97.5%.

[0050] Example 2

[0051] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0052] (2) Take an appropriate amount of cut sample and weigh it (mass is m1 = 30 g) and put it into the reactor. According to the ratio of [Emim][OAc](g):DMSO(g) = 0.32:1 and the liquid-to-solid ratio of 20 mL / g, [Emim][OAc], DMSO and the sample are mixed. The temperature of the reactor is set to 200 ° C, the holding time is 7 h, the pressure is 7 MPa, and the stirring rate is 130 RPM. After the reaction is completed, the temperature and pressure are lowered to obtain a solid-liquid mixture.

[0053] (3) The solid-liquid mixture was washed and filtered. The resulting solid phase product was dried in an oven at 105°C for 5 hours and weighed (mass m2 = 20.445 g). The calculated degradation rate of the organic components was 99.53%. (Compared to Example 1, the difference is that the ionic liquid is [Emim][OAc] and the organic solvent is DMSO.)

[0054] Example 3

[0055] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0056] (2) Take an appropriate amount of cut sample, weigh it (mass m1 = 30 g), and put it into the reactor. Mix [Bmim]Cl, DMSO and the sample according to the ratio of [Bmim]Cl (g): DMSO (g) = 0.27:1 and the liquid-to-solid ratio of 20 mL / g. Set the temperature of the reactor to 200 °C, the holding time to 7 h, the stirring rate to 130 RPM, and cool and reduce the temperature and pressure after the reaction to obtain a solid-liquid mixture.

[0057] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 20.571 g). The calculated degradation rate of the organic component was 98.22%.

[0058] Example 4

[0059] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0060] (2) Take an appropriate amount of cut sample and weigh it (mass is m1 = 30 g) and put it into the reactor. Mix [Bmim]OH, DMAP and the sample according to the ratio of [Bmim]OH (g): DMAP (g) = 0.46:1 and the liquid-to-solid ratio of 20 mL / g. Set the temperature of the reactor to 175 ° C, the holding time to 7 h, the stirring rate to 130 RPM, and cool and reduce the pressure after the reaction to obtain a solid-liquid mixture.

[0061] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 20.94 g). The calculated degradation rate of the organic component was 94.38%.

[0062] Example 5

[0063] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0064] (2) Take an appropriate amount of cut sample, weigh it (mass m1 = 30 g), and put it into the reactor. Mix [Bmim]OH, NMP and the sample according to the ratio of [Bmim]Br (g): NMP (g) = 0.31:1 and the liquid-to-solid ratio of 20 mL / g. Set the temperature of the reactor to 180 ° C, the holding time to 7 h, the stirring rate to 130 RPM, and cool and reduce the pressure after the reaction to obtain a solid-liquid mixture.

[0065] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 20.735 g). The calculated degradation rate of the organic component was 96.51%.

[0066] Example 6

[0067] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0068] (2) Take an appropriate amount of cut sample and weigh it (mass is m1 = 30 g) and put it into the reactor. According to the ratio of [Emim]BF4 (g): DMSO (g) = 0.31:1 and the liquid-to-solid ratio of 20 mL / g, [Bmim]OH and NMP are mixed with the sample. The temperature of the reactor is set to 180 ° C, the holding time is 7 h, and the stirring rate is 130 RPM. After the reaction is completed, the temperature and pressure are lowered to obtain a solid-liquid mixture.

[0069] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 21.804 g). The calculated degradation rate of the organic component was 85.37%.

[0070] Example 7

[0071] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0072] (2) Take an appropriate amount of cut sample and weigh it (mass is m1 = 30 g) and put it into the reactor. According to the ratio of [Bdmim]OH (g): DMAP (g) = 0.35:1 and the liquid-to-solid ratio of 20 mL / g, [Bmim]OH and NMP are mixed with the sample. The temperature of the reactor is set to 185 ° C, the holding time is 7 h, and the stirring rate is 130 RPM. After the reaction is completed, the temperature and pressure are lowered to obtain a solid-liquid mixture.

[0073] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 21.399 g). The calculated degradation rate of the organic component was 89.59%.

[0074] Example 8

[0075] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0076] (2) Take an appropriate amount of cut sample, weigh it (mass m1 = 30 g), and put it into the reactor. Mix [Bmim]OH, NMP and the sample according to the ratio of [BMPy]Cl (g): DMI (g) = 0.42:1 and the liquid-to-solid ratio of 20 mL / g. Set the temperature of the reactor to 190 ° C, the holding time to 7 h, the stirring rate to 130 RPM, and cool and reduce the pressure after the reaction to obtain a solid-liquid mixture.

[0077] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 22.942 g). The calculated degradation rate of the organic component was 73.52%.

[0078] Example 9

[0079] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0080] (2) Take an appropriate amount of cut sample, weigh it (mass m1 = 30 g), and put it into the reactor. Mix [Bmim]OH, NMP and the sample according to the ratio of [BMPy]Br (g): DMF (g) = 0.30:1 and the liquid-to-solid ratio of 20 mL / g. Set the temperature of the reactor to 200 ° C, the holding time to 7 h, the stirring rate to 130 RPM, and cool and reduce the pressure after the reaction to obtain a solid-liquid mixture.

[0081] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 22.531 g). The calculated degradation rate of the organic components was 77.8%.

[0082] Example 10

[0083] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0084] (2) Take an appropriate amount of cut sample and weigh it (mass m1 = 30 g) and put it into the reactor. Mix [Bmim]OH and NMP with the sample according to the ratio of [EMPy]OH (g): DMI (g) = 0.35:1 and the liquid-to-solid ratio of 20 mL / g. Set the temperature of the reactor to 180 ° C, the holding time to 7 h, the stirring rate to 130 RPM, and cool and reduce the pressure after the reaction to obtain a solid-liquid mixture.

[0085] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 20.829 g). The calculated degradation rate of the organic component was 95.53%.

[0086] Example 11

[0087] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0088] (2) Take an appropriate amount of cut sample, weigh it (mass m1 = 30 g), and put it into the reactor. Mix [Bmim]OH, NMP and the sample according to the ratio of [HMPy]Cl (g): DMSO (g) = 0.28:1 and the liquid-to-solid ratio of 20 mL / g. Set the temperature of the reactor to 210 ° C, the holding time to 7 h, the stirring rate to 130 RPM, and cool and reduce the pressure after the reaction to obtain a solid-liquid mixture.

[0089] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 21.672 g). The calculated degradation rate of the organic component was 86.75%.

[0090] Example 12

[0091] (1) Crush and cut the retired wind turbine blade materials to obtain samples of appropriate size, which are then dried and set aside.

[0092] (2) Take an appropriate amount of cut sample, weigh it (mass m1 = 30 g), and put it into the reactor. Mix [Bmim]OH, NMP and the sample according to the ratio of [BMPy][DEP](g):DMSO(g) = 0.43:1 and the liquid-to-solid ratio of 20 mL / g. Set the temperature of the reactor to 200°C, the holding time to 7 h, and the stirring rate to 130 RPM. After the reaction is completed, cool and reduce the pressure to obtain a solid-liquid mixture.

[0093] (3) The solid-liquid mixture was washed and filtered, and the obtained solid phase product was placed in an oven at 105° C. and dried for 5 h, then taken out and weighed (mass m2 = 21.424 g). The calculated degradation rate of the organic component was 89.33%.

[0094] Comparative Example 1

[0095] The only difference from Example 1 is that the ionic liquid in step (2) is replaced by water, and only an organic solvent is added. The organic solvent added is the same as in Example 1, and the remaining steps and parameters are the same as in Example 1. In this comparative example, m2 = 29.692 g, and the calculated organic component degradation rate is 3.21%.

[0096] Comparative Example 2

[0097] The only difference from Example 2 is that the ionic liquid in step (2) is replaced with water, and only an organic solvent is added. The organic solvent added is the same as in Example 2, and the remaining steps and parameters are the same as in Example 2. In this comparative example, m2 = 29.956 g; the solid resin solubility in the filler material of this comparative example is calculated using the formula to be 0.46%.

[0098] Comparative Example 3

[0099] The only difference from Example 2 is that the organic solvent in step (2) is replaced with water, and only an ionic liquid is added. The ionic liquid added is the same as in Example 2, and the remaining steps and parameters are the same as in Example 2. In this comparative example, m2 = 29.267 g; the solid resin solubility in the filler material of this comparative example is calculated using the formula to be 7.64%.

[0100] The statistical table of degradation rates of organic components in Examples 1-5 and Comparative Examples 1-2 is shown in Table 1.

[0101] Table 1

[0102]

[0103]

[0104] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for degrading retired wind turbine blade materials using a composite solvent, characterized in that: The following steps are involved: Physically crush the retired wind turbine blades to obtain samples; mixing the sample with an organic solvent and an ionic liquid and reacting the mixture; The ionic liquid is an imidazolium salt ionic liquid or a pyridinium salt ionic liquid; The imidazolium salt ionic liquid is at least one of 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium hydroxide, 1-ethyl-3-methylimidazolium acetate and 1-butyl-3-methylimidazolium hydroxide; The pyridinium salt ionic liquid is at least one of 1-butyl-4-methylpyridinium chloride, 1-butyl-4-methylpyridinium bromide, 1-ethyl-3-methylpyridinium hydroxide, 1-hexyl-3-methylpyridinium chloride and 1-butyl-3-methylpyridinium diethyl phosphate.

2. The method for degrading retired wind turbine blade materials with a composite solvent according to claim 1, characterized in that: The retired wind turbine blades include fiber-reinforced thermosetting resin-based composite materials.

3. The method for degrading retired wind turbine blade materials with a composite solvent according to claim 1, characterized in that: The organic solvent is a polar aprotic solvent.

4. The method for degrading retired wind turbine blade materials using a composite solvent according to claim 3, characterized in that: The polar aprotic solvent is at least one of toluene, dimethylacetamide, 4-dimethylaminopyridine, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, N-methylpyrrolidone and dimethylformamide.

5. The method for degrading retired wind turbine blade materials with a composite solvent according to claim 1, characterized in that: The mass ratio of the ionic liquid to the organic solvent is (0.07-1):

1.

6. The method for degrading retired wind turbine blade materials with a composite solvent according to claim 1, characterized in that: The liquid-to-solid ratio of the total volume of the ionic liquid and the organic solvent to the sample is 5 to 100:

1.

7. The method for degrading retired wind turbine blade materials with a composite solvent according to claim 1, characterized in that: The reaction temperature is 110-250° C., the reaction time is 1-24 hours, and the pressure is 1-10 MPa.

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