Method for recycling wind power blade type composite material

Abstract

The invention discloses a method for recycling a wind power blade type composite material, and belongs to the technical field of solid waste recycling. The method comprises the following steps: cutting and crushing the wind power blade composite material, and performing multi-stage screening to respectively obtain powder, a fiber bundle and powder mixture, a fiber bundle and particle mixture and a coarse material; respectively performing length screening on the fiber bundle and powder mixture and the fiber bundle and particle mixture to obtain a fiber bundle-shaped material, a powder material and short fiber-shaped material and a particle and short fiber-shaped material; the fiber bundle-shaped material is used for preparing a fiber material molded product; and the powder obtained through sorting is used for preparing a compression molding product. According to the method disclosed by the invention, various materials with uniform and stable properties are successfully obtained and prepared into standardized products suitable for different scenes, so that the quality stability of final application products is effectively ensured. When the application products are scrapped, the application products can still be recycled through the method, and a sustainable development closed-loop system is formed.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste resource utilization, and particularly relates to a method for recycling composite materials of wind turbine blades. Background Art

[0002] Wind turbine blades are mainly composed of glass fiber-reinforced epoxy resin-based composite materials. After being scrapped, it is extremely difficult to dispose of and recycle them. The disposal and recycling of waste wind turbine blades have become the key points restricting the green, low-carbon and circular development of China's wind power industry. At present, the conventional disposal method of waste wind turbine blades is to cut and temporarily store them. Some enterprises finely cut wind turbine blades into various profiles of different specifications and shapes, and then use them in industries such as animal husbandry and logistics, but it is not easy to form standardized products.

[0003] The invention patent "A composite material molded product, its preparation method and system" (CN117700934A) mixes waste wind turbine blades, wood chips and modified MDI glue and then presses them into municipal building materials such as pressed trays, but this patent does not sort the crushed materials of wind turbine blades. According to the practice of crushing wind turbine blades, the crushed materials of wind turbine blades are a mixture of powder materials, flocculent materials and fiber bundles, and the proportion of each component fluctuates. Due to the unstable properties of the crushed materials of wind turbine blades, direct use without sorting is not conducive to the quality stability of the end products.

[0004] Wind turbine blades are mainly made of glass fiber-reinforced epoxy resin-based composite materials, and their recycling after being scrapped faces great challenges. The proper disposal of waste wind turbine blades has become an important bottleneck restricting the realization of green, low-carbon and circular development of China's wind power industry. At present, the main treatment method of waste wind turbine blades is to cut and temporarily store them. Some enterprises try to finely cut wind turbine blades into profiles of different specifications and shapes and apply them to fields such as animal husbandry and logistics, but due to their difficulty in forming standardized products, the actual application range is limited.

[0005] The invention patent "A composite material molded product, its preparation method and system" with the publication number of CN117700934A proposes a solution, that is, mixing waste wind turbine blades with wood chips and modified MDI glue, and then making them into municipal building materials such as trays through a pressing process. However, the applicant found that this patent does not involve the sorting process of the crushed materials of wind turbine blades. After the wind turbine blades are crushed, a mixture of powder materials, flocculent materials and fiber bundles will be generated, and the proportion of each component may fluctuate with the change of raw materials. Due to the unstable properties of the crushed materials, if they are directly used without sorting, it will be difficult to ensure the quality stability of the end products, thus limiting their application prospects in high-value-added fields.

[0006] Therefore, providing a method for recycling composite materials of wind turbine blades that can ensure the quality stability of end products has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] The objective of the present invention is to provide a method for recycling wind turbine blade composite materials, so as to solve the problem of unstable quality of end products formed during the recycling of wind turbine blade composite materials in the prior art.

[0008] To achieve the above objective, the technical solution adopted by the present invention is as follows:

[0009] The present invention discloses a method for recycling wind turbine blade composite materials, including the following steps:

[0010] S1. Cutting: Cut the wind turbine blade composite materials in situ.

[0011] S2. Crushing: Crush the cut wind turbine blade composite materials to obtain a crushed mixture of wind turbine blade composite materials.

[0012] S3. Sorting: Conduct multi-stage screening on the wind turbine blade mixture to separately obtain powder, a mixture of fiber bundles and powder, a mixture of fiber bundles and particles, and coarse materials; conduct length screening on the mixture of fiber bundles and powder to obtain first long fiber bundle-shaped materials, powder, and short fiber-shaped materials; conduct length screening on the mixture of fiber bundles and particles to obtain second long fiber bundle-shaped materials, particles, and short fiber-shaped materials.

[0013] S4. Utilization by quality: Use the first long fiber bundle-shaped materials and / or the second long fiber bundle-shaped materials sorted in step S3 to prepare fiber molded products; use the powder sorted in step S3 to prepare compression molding products.

[0014] The wind turbine blade composite materials refer to glass fiber-reinforced composite materials used for manufacturing wind turbine blades and nacelle covers.

[0015] In some embodiments of the present invention, in step S2, the maximum size of the crushed mixture does not exceed 30 mm.

[0016] In some embodiments of the present invention, screen the crushed mixture through a linear vibrating screen to obtain powder with a particle size less than 0.075 mm, a mixture of fiber bundles and powder with a particle size of 0.075 - 1 mm, a mixture of fiber bundles and particles with a particle size of 1 - 3 mm, and coarse materials with a particle size greater than 3 mm.

[0017] In some embodiments of the present invention, conduct length screening on the mixture of fiber bundles and powder, and the screen hole diameter during length screening is 1 mm - 1 cm to obtain first long fiber bundle-shaped materials, powder, and short fiber-shaped materials.

[0018] In some embodiments of the present invention, the fiber bundle and the particle mixture are subjected to length screening, and the aperture diameter during length screening is 1 mm - 1 cm, to obtain a second long fiber bundle-like material, particles, and short fiber-like materials.

[0019] In some embodiments of the present invention, the coarse materials, powder materials, short fiber-like materials, particles, and short fiber-like materials sorted in step S3 are all returned to step S2 for crushing again.

[0020] In some embodiments of the present invention, the method for preparing the fiber material molded product includes the following steps:

[0021] After cutting and crushing the straw, straw shavings are obtained, dried, and uniformly mixed with the long fiber bundle-like material and the adhesive. The mixed material is hot-pressed and formed by a mold to obtain a molded product; the long fiber bundle-like material is the first long fiber bundle-like material or / and the second long fiber bundle-like material.

[0022] In some embodiments of the present invention, taking the total amount of straw shavings, long fiber bundle-like material, and adhesive as 1, the mass ratio is (0.1 - 0.5) : (0.3 - 0.86) : (0.04 - 0.2);

[0023] Preferably, the adhesive is diphenylmethane diisocyanate adhesive and / or urea-formaldehyde resin adhesive.

[0024] In some embodiments of the present invention, the method for preparing the compression molding product includes the following steps:

[0025] The thermoplastic waste plastic powder, the wind power blade composite material powder, the new thermoplastic plastic, and the additives are added to a mixer and mixed evenly. The uniformly mixed mixture is added to a hot press mold and hot-pressed and formed.

[0026] In some embodiments of the present invention, taking the total amount of the thermoplastic waste plastic powder, the wind power blade composite material powder, the new thermoplastic plastic, and the additives as 1, the mass ratio is (0.4 - 0.8) : (0.1 - 0.3) : (0 - 0.25) : (0.01 - 0.05);

[0027] Preferably, the new thermoplastic plastic includes at least one of polypropylene, polyvinyl chloride, and polyethylene;

[0028] Preferably, the additives include at least one of silane coupling agent, lubricant, antioxidant, and colorant;

[0029] Preferably, the particle size of the thermoplastic waste plastic powder is less than 0.075 mm.

[0030] In some embodiments of the present invention, after the fiber material molded products and compression molded products are scrapped, they are recycled by steps S1 to S4.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention is scientifically designed and ingeniously conceived. By cutting and sorting the wind power blade composite materials, various materials with uniform and stable properties are successfully obtained. Further, by making full use of the characteristics of these materials with different shapes, standardized molded products suitable for different scenarios (with different quality requirements) are manufactured, thus effectively ensuring the quality stability of the final application products. More importantly, when these molded products are scrapped, they can still be recycled through the present invention, forming a sustainable development closed-loop system.

[0033] The present invention prepares molded products using waste wind power blades and thermoplastic waste plastics as the main raw materials, which not only saves raw materials, but also does not require drying treatment for waste wind power blades, thermoplastic waste plastics and other waste materials, with obvious energy-saving and emission-reduction effects, and has good ecological benefits and economic and social benefits.

[0034] The molded products of the present invention have excellent performance and the characteristics of recycling. By crushing and sorting the wind power blades, two products, namely fiber bundles and powders, can be obtained, and the characteristics of these two sorted products are fully utilized for hierarchical utilization. Among them, the mechanical properties of the glass fiber bundles in the wind power blade composite materials are significantly better than those of plant fibers. Therefore, the prepared molded trays also have better mechanical properties than the plant fiber molded trays. At the same time, a large number of glass fibers with a large aspect ratio are contained in the powder of the wind power blade composite materials, and these fibers can effectively improve the mechanical properties of the powder molded products. In addition, the molded products can be crushed and used repeatedly as raw materials after being scrapped, realizing the efficient recycling of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Attached Figure 1 is a process flow chart of the method of the present invention.

[0036] Attached Figure 2 is a schematic diagram of a fiber material molded product.

[0037] Attached Figure 3 is a schematic diagram of a compression molded product. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0039] Embodiment 1

[0040] As shown in the attached Figure 1 figure, this embodiment discloses a method for recycling wind turbine blade composite materials, including the following steps:

[0041] S1. Cutting: Cut the wind turbine blade composite materials in place; use mobile mechanical cutting equipment to cut the wind turbine blade composite materials into block materials with a size not greater than 0.8 m.

[0042] S2. Crushing: Crush the cut wind turbine blade composite materials to obtain a crushed mixture of wind turbine blade composite materials; the form of the crushed mixture is mainly fiber bundles and powders; the aperture of the discharge screen is 12 mm.

[0043] The cutting and crushing devices are both prior arts. In this embodiment, the "system for efficiently cutting and crushing large-size composite solid waste in place" disclosed in the patent with the publication number CN219768832U is used for cutting and crushing.

[0044] S3. Sorting: Screen the crushed mixture through a linear vibrating screen to obtain powders with a particle size less than 0.075 mm, a mixture of fiber bundles and powders with a particle size of 0.075 - 1 mm, a mixture of fiber bundles and particles with a particle size of 1 - 3 mm, and coarse materials with a particle size greater than 3 mm.

[0045] Perform length screening on the mixture of fiber bundles and powders. The screen hole diameter during length screening is 1 mm - 1 cm to obtain first long fiber bundle materials, powders, and short fiber materials.

[0046] Perform length screening on the mixture of fiber bundles and particles. The screen hole diameter during length screening is 1 mm - 1 cm to obtain second long fiber bundle materials, particles, and short fiber materials.

[0047] The coarse materials, powders, short fiber materials, particles, and short fiber materials obtained by sorting in step S3 are all returned to step S2 for crushing again.

[0048] The sorting device for the crushed mixture is a prior art. In this embodiment, a sorting device for the crushed materials of wind power blades disclosed in the patent with the publication number of CN220864488U is used for sorting. Specifically, during use, the specific gravity screening system of the sorting device for the crushed materials of wind power blades is removed, and each discharge port of the vibration screening system is correspondingly connected to a length screening system, wherein the vibration screening system is a 2 - 3 - layer linear vibrating screen.

[0049] Example 2

[0050] This embodiment discloses a method for preparing a fiber - material molded product by using the long - fiber bundle - shaped material sorted in Example 1. The specific steps are as follows:

[0051] Step 1. Straw cutting and crushing

[0052] The straw is subjected to cutting and crushing treatment so that its maximum size is less than 3 cm to obtain straw shavings.

[0053] Step 2. Drying

[0054] The straw shavings are dried, and the moisture content of the dried straw shavings is less than 10%.

[0055] Step 3. Mixing

[0056] The dried straw shavings are mixed evenly with the long - fiber bundle - shaped material and the adhesive to obtain a mixed material. The long - fiber bundle - shaped material is a mixture of the first long - fiber bundle - shaped material and the second long - fiber bundle - shaped material sorted in Example 1. The total amount of straw shavings, long - fiber bundle - shaped material, and adhesive is counted as 1, and their mass ratio is 0.5:0.3:0.2. The adhesive is diphenylmethane diisocyanate adhesive.

[0057] The evenly - mixed mixed material is added into a hot - press mold; after the mixed material is laid flat in the mold, hot - press forming is carried out. The hot - press forming is divided into three steps: hot - pressing, pressure - maintaining, and pressure - releasing; among them, the hot - press temperature is 110 - 150 °C, the hot - press pressure is 10 - 15 Mpa, the hot - press time is 160 - 200 s, and the pressure - maintaining time is 70 - 130 s; after pressure - releasing, the molded product is taken out, cooled, and the edges are ground.

[0058] The molded tray (length * width * height = 1200 mm * 1000 mm * 15 mm) in this embodiment weighs about 20 kg, has a static load of 14520 kg, and a dynamic load of 4300 kg. The molded product can be specifically prepared into a molded tray, a cable tray, a wooden plug, a packaging box assembly, etc. according to different molds. And after the molded product is scrapped, it can still be recycled through the present invention to form a sustainable development closed - loop system.

[0059] Example 3

[0060] This embodiment discloses a method for preparing a compression molding product using the powder with a particle size less than 0.075 mm sorted in Embodiment 1. The specific steps are as follows:

[0061] (1) Crushing of thermoplastic waste plastics: The thermoplastic waste plastics are crushed to a particle size less than 0.075 mm to obtain thermoplastic waste plastic powder.

[0062] (2) The thermoplastic waste plastic powder, the composite powder of wind turbine blade type, the new thermoplastic plastic and the additives are added to a mixer and mixed evenly to obtain a mixture.

[0063] The composite powder of wind turbine blade type is the powder with a particle size less than 0.075 mm sorted in Embodiment 1. The total amount of the thermoplastic waste plastic powder, the composite powder of wind turbine blade type, the new thermoplastic plastic and the additives is counted as 1, and their mass ratio is 0.6:0.15:0.20:0.05;

[0064] The new thermoplastic plastic is polypropylene, and the additives are silane coupling agent, lubricant, antioxidant and colorant; their mass ratio is 1:14:1:8.

[0065] (3) The mixture evenly mixed in step (2) is added to a hot pressing mold; after the mixture is laid flat in the mold, hot pressing is carried out. The hot pressing process is divided into three steps: hot pressing, pressure holding and pressure relief; among them, the hot pressing temperature is 180 - 190 °C, the hot pressing pressure is 8 - 12 Mpa, the hot pressing time is 10 min, and the pressure is held for 10 min; after pressure relief, the compression molding product is taken out, cooled and then the edges are ground.

[0066] The compression molding tray of this embodiment (length * width * height = 1200 mm * 1000 mm * 15 mm) weighs about 11.5 kg, has a static load of 1800 kg and a dynamic load of 960 kg.

[0067] The compression molding product can be specifically prepared into a compression molding tray, a manhole cover, a trash can, a building formwork, etc. according to different molds. And after the compression molding product is scrapped, it can still be recycled through the present invention to form a sustainable closed-loop system.

[0068] Finally, it should be noted that: the above embodiments are only relatively preferred embodiments of the present invention to illustrate the technical solutions of the present invention, rather than limiting it, and certainly not limiting the patent scope of the present invention. Any modification or polishing made without substantial significance in the main design idea and spirit of the present invention, as long as the technical problems solved are still the same as those of the present invention, should be included in the protection scope of the present invention; in addition, directly or indirectly applying the technical solutions of the present invention to other related technical fields shall also be included in the patent protection scope of the present invention by the same token.

Claims

1. A method for recycling composite materials of wind turbine blades, characterized in that It includes the following steps: S1. Cutting: Cut the composite materials of wind turbine blades in place; S2. Crushing: Crush the cut composite materials of wind turbine blades to obtain crushed mixture of composite materials of wind turbine blades; S3. Sorting: Conduct multi-stage screening on the mixture of wind turbine blade materials to obtain powder, mixture of fiber bundle and powder, mixture of fiber bundle and particles, and coarse materials respectively; Conduct length screening on the mixture of fiber bundle and powder to obtain first long fiber bundle materials, powder materials and short fiber materials; Conduct length screening on the mixture of fiber bundle and particles to obtain second long fiber bundle materials, particles and short fiber materials; S4. Utilization by quality: Use the first long fiber bundle materials and / or the second long fiber bundle materials sorted in step S3 to prepare fiber molding products; Use the powder sorted in step S3 to prepare compression molding products; The composite materials of wind turbine blades refer to glass fiber reinforced composite materials used for manufacturing wind turbine blades and nacelle covers.

2. A method for recycling wind turbine blade composite materials according to claim 1, characterized in that In step S2, the maximum size of the crushed mixture does not exceed 30 mm.

3. A method for recycling composite materials of wind turbine blades according to claim 1, characterized in that, Screen the crushed mixture through a linear vibrating screen to obtain powder with a particle size less than 0.075 mm, mixture of fiber bundle and powder with a particle size of 0.075 - 1 mm, mixture of fiber bundle and particles with a particle size of 1 - 3 mm, and coarse materials with a particle size greater than 3 mm.

4. A method for recycling composite materials of wind turbine blades according to any one of claims 1 to 3, characterized in that Conduct length screening on the mixture of fiber bundle and powder, and the screen hole diameter during length screening is 1 mm - 1 cm to obtain first long fiber bundle materials, powder materials and short fiber materials.

5. A method for recycling composite materials for wind turbine blades according to any one of claims 1 to 3, characterized in that, Conduct length screening on the mixture of fiber bundle and particles, and the screen hole diameter during length screening is 1 mm - 1 cm to obtain second long fiber bundle materials, particles and short fiber materials.

6. A method for recycling composite materials of wind turbine blades according to any one of claims 1 to 3, characterized in that The coarse materials, powder materials and short fiber materials, particles and short fiber materials sorted in step S3 are all returned to step S2 for crushing again.

7. A method for recycling composite materials for wind turbine blades according to any one of claims 1 to 3, characterized in that, The preparation method of the fiber molding product includes the following steps: Cut and crush straw to obtain straw shaving materials, dry them, mix them evenly with long fiber bundle materials and adhesives, and hot press the mixed materials through a mold to obtain a molding product; The long fiber bundle materials are the first long fiber bundle materials and / or the second long fiber bundle materials.

8. A method for recycling wind turbine blade composite materials according to claim 7, characterized in that The total amount of straw shavings, long fiber bundle materials and adhesives is counted as 1, and their mass ratio is (0.1 - 0.5):(0.3 - 0.86):(0.04 - 0.2); Preferably, the adhesive is diphenylmethane diisocyanate adhesive and / or urea formaldehyde resin adhesive.

9. A method for recycling composite materials of wind turbine blades according to any one of claims 1 to 3, characterized in that, The preparation method of the compression molding product includes the following steps: Add thermoplastic waste plastic powder, powder of composite materials of wind turbine blades, new thermoplastic plastic and additives into a mixer and mix them evenly, and add the evenly mixed mixture into a hot press mold for hot pressing and forming.

10. A method for recycling composite materials of wind turbine blades according to claim 8, characterized in that, The total amount of thermoplastic waste plastic powder, powder of composite materials of wind turbine blades, new thermoplastic plastic and additives is counted as 1, and their mass ratio is (0.4 - 0.8):(0.1 - 0.3):(0 - 0.25):(0.01 - 0.05); Preferably, the new thermoplastic plastic includes at least one of polypropylene, polyvinyl chloride and polyethylene; Preferably, the auxiliary agent includes at least one of a silane coupling agent, a lubricant, an antioxidant, and a colorant; Preferably, the particle size of the thermoplastic waste plastic powder is less than 0.075 mm.

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