A method for separating glass fibers from decommissioned wind turbine blades

Abstract

The present application relates to the technical field of recycling glass fibers in decommissioned wind turbine blades, and provides a method for separating glass fibers from decommissioned wind turbine blades, which has a high degradation rate, a high glass fiber strength retention rate, a low glass fiber breakage rate, and can also have a high length 1-10 mm fiber yield and a high length 3-7 mm fiber proportion. The method comprises the following steps: S1, disassembling the decommissioned wind turbine blade to remove the non-glass fiber composite material part; S2, coarsely crushing the disassembled blade; then finely crushing to obtain fine crushing materials; S3, placing the fine crushing materials in a degradation solution to perform a degradation reaction at a temperature of 150 DEG C or higher, filtering after the reaction is completed to obtain glass fiber residues; the degradation solution is a benzyl alcohol aqueous solution added with ferric chloride and / or zinc chloride; S4, cleaning the glass fiber residues, and then drying to obtain pure glass fibers.

Description

Technical Field

[0001] This invention relates to the field of glass fiber recycling technology in decommissioned wind turbine blades, and specifically to a method for separating glass fibers from decommissioned wind turbine blades. Background Technology

[0002] With the rapid development of the global wind power industry, the disposal of a large number of retired wind turbine blades has become an urgent problem. Wind turbine blades are mainly composed of glass fiber reinforced composite materials, in which glass fibers possess excellent properties such as high strength and high modulus. If they can be effectively separated and recycled, resources can be reused. However, currently used disposal methods have many drawbacks. Simple mechanical crushing methods, although they can break the blades, leave the glass fibers tightly bound to the resin matrix, making effective separation impossible. The recovered glass fibers are of poor quality and difficult to reuse. Chemical degradation methods can dissolve the resin matrix, but the processing efficiency is low, and large amounts of chemical reagents are required, resulting in high costs. Furthermore, it may damage the performance of the glass fibers. Therefore, there is an urgent need for an efficient separation method that can guarantee the quality of the glass fibers, enabling the effective recycling of glass fibers from retired wind turbine blades. Summary of the Invention

[0003] To address at least one deficiency in existing technologies, this invention provides a method for separating glass fibers from decommissioned wind turbine blades. This method effectively separates glass fibers from decommissioned wind turbine blades, improving the quality and efficiency of glass fiber recycling. It not only achieves high degradation rate, high glass fiber strength retention rate, and low glass fiber breakage rate, but also simultaneously ensures a high yield of 1-10mm fibers and a high proportion of 3-7mm fibers, demonstrating broad application prospects.

[0004] To achieve its objective, the present invention provides the following technical solution:

[0005] This invention provides a method for separating glass fibers from decommissioned wind turbine blades, comprising the following steps:

[0006] S1. Disassemble the retired wind turbine blades and remove the non-glass fiber composite material parts;

[0007] S2. The disassembled blades are coarsely crushed to obtain fragments with a size of 10-20cm; then finely crushed to make the fragment size less than 1cm, while the proportion of 40 mesh or above is ≥70wt% (e.g., 70, 80, 90, 95, 98wt%, etc.), to obtain finely crushed material.

[0008] S3. The finely crushed material is placed in a degradation solution and subjected to a degradation reaction at a temperature above 150°C. After the reaction is completed, it is filtered to obtain glass fiber filter residue. The degradation solution is an aqueous solution of benzyl alcohol with added ferric chloride and / or zinc chloride.

[0009] S4. The glass fiber filter residue is washed and then dried to obtain pure glass fiber.

[0010] Preferably, in step S3, the volume of benzyl alcohol in the aqueous solution accounts for 10-90% of the total volume of benzyl alcohol and water, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90%, etc.

[0011] Preferably, in step S3, the liquid-to-solid ratio of the degradation solution and the finely crushed material is ≥5, in ml / g.

[0012] And / or, in step S3, the ratio of the total mass of the ferric chloride and zinc chloride to the mass of the finely crushed material is ≥0.1:20.

[0013] Preferably, in step S3, the liquid-to-solid ratio of the degradation solution to the finely crushed material is 5-20 (e.g., 5, 7, 9, 10, 12, 15, 17, 20, etc.), in ml / g.

[0014] Preferably, the ratio of the total mass of ferric chloride and zinc chloride to the mass of the finely crushed material is 0.1-2:20, for example, 0.1:20, 0.5:20, 0.7:20, 1:20, 1.5:20, 2:20, etc.

[0015] Preferably, in step S3, the temperature of the degradation reaction is 200-400℃, for example, 200, 250, 300, 350, 400℃, etc.;

[0016] And / or, in step S3, the degradation reaction time is ≤30 min.

[0017] Preferably, in step S3, the degradation reaction time is 5-30 min, for example, 5, 15, 20, 25, 30 min, etc.

[0018] Preferably, in step S4, the cleaning involves rinsing the glass fiber filter residue multiple times with clean water.

[0019] Preferably, in step S4, the drying process involves drying the glass fibers until the moisture content is less than 1%.

[0020] Preferably, the drying temperature is 80-100℃.

[0021] The technical solution provided by this invention has the following beneficial effects:

[0022] The method of this invention can efficiently separate high-quality glass fibers from decommissioned wind turbine blades. It has a short degradation time, high degradation rate, high glass fiber strength retention rate, and low breakage rate. Moreover, it can achieve a high yield of 1-10mm long fibers and a high proportion of 3-7mm long fibers, which is convenient for downstream applications. Detailed Implementation

[0023] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0025] This invention provides a method for separating glass fibers from decommissioned wind turbine blades, comprising the following steps:

[0026] S1. Disassemble the retired wind turbine blades and remove non-glass fiber composite parts such as connectors and metal components; glass fiber composites refer to composites of glass fiber and resin.

[0027] S2. The disassembled blades are coarsely crushed to obtain fragments with a size of 10-20cm; then finely crushed to make the fragment size less than 1cm, while the proportion of 40 mesh or larger is ≥70wt% (that is, when sieved with a 40 mesh screen, the proportion of the material on the screen is ≥70wt%), to obtain finely crushed material.

[0028] S3. The finely crushed material is placed in a degradation solution and subjected to a degradation reaction at a temperature above 150°C. After the reaction is completed, it is filtered to obtain glass fiber filter residue. The degradation solution is an aqueous solution of benzyl alcohol with added ferric chloride and / or zinc chloride.

[0029] S4. The glass fiber filter residue is washed and then dried to obtain pure glass fiber.

[0030] In this invention, after the blades are disassembled, they are first coarsely crushed into fragments of 10-20cm in size, and then finely crushed into fine fragments of less than 1cm in size, with a mesh size of ≥70wt% and a particle size of 40 mesh or larger. These finely crushed materials are then chemically degraded in a benzyl alcohol aqueous solution containing ferric chloride and / or zinc chloride. This process significantly shortens the degradation time and achieves a high degradation rate. Furthermore, the final glass fiber yield is high, with a high percentage of 1-10mm long glass fibers (up to 75%), and a significant proportion of fibers with a length of 3-7mm. The fiber size conformity is high, and the resulting fibers retain high strength, exhibiting a low breakage rate during subsequent use. In glass fiber applications, such as catalysts and automotive baffles, it is often necessary to select fibers with a length of 1-10mm, especially 3-7mm. Therefore, a high proportion of glass fibers meeting these length requirements is beneficial for the direct application of the recovered glass fibers.

[0031] In the text, "fragments with a size of 10-20cm" refers to the length of the fragments. "Fragments with a size of less than 1cm and a particle size of 40 mesh or larger accounting for ≥70wt%" means that the fragment length does not exceed 1cm and the particle size of 40 mesh or larger accounts for no less than 70%.

[0032] Preferably, in the degradation solution of step S3, the volume of benzyl alcohol in the aqueous solution accounts for 10-90% of the total volume of benzyl alcohol and water.

[0033] Preferably, in step S3, the liquid-to-solid ratio of the degradation solution and the finely crushed material is ≥5, preferably 5-20, in ml / g.

[0034] Preferably, in step S3, the ratio of the total mass of ferric chloride and zinc chloride to the mass of the finely crushed material is ≥0.1:20. More preferably, the ratio of the total mass of ferric chloride and zinc chloride to the mass of the finely crushed material is 0.1-2:20.

[0035] Preferably, in step S3, the temperature of the degradation reaction is 200-400℃.

[0036] In this invention, the degradation time required in step S3 is short, with the degradation reaction time ≤30min, for example, 5-30min, which can significantly improve the recovery efficiency and shorten the process cycle.

[0037] In step S3, the filtration can be performed using common filtration methods in the art, such as filtering with a stainless steel filter screen, and then the resulting glass fiber filter cake is transferred to a washing tank. Preferably, in step S4, the washing involves rinsing the glass fiber filter cake multiple times with clean water until the pH value of the washing water is close to neutral, thereby removing chemical degradation agents and residual resin fragments adhering to the surface of the glass fibers. In some examples, each rinsing time is 10-15 minutes, and preferably, the number of rinsings is no less than 3 times.

[0038] Preferably, in step S4, the drying process involves drying the glass fibers until the moisture content is less than 1%. Common drying methods in the art can be used, such as spreading the cleaned glass fiber filter residue evenly on a stainless steel tray and placing it in a hot air circulating drying oven for drying. Preferably, in step S4, the drying temperature is 80-100°C, and the drying time is, for example, 2-4 hours.

[0039] The method of the present invention has at least the following beneficial effects:

[0040] High-efficiency separation: This invention combines mechanical crushing with chemical degradation. During the mechanical crushing process, the coarse crushing size is controlled to be 10-20cm, and the fine crushing size is ≤1cm with a 40-mesh or larger proportion of ≥70wt%. At the same time, a specific degradation solution containing benzyl alcohol aqueous solution with ferric chloride and / or zinc chloride is used, which significantly improves the separation efficiency between glass fiber and resin matrix. Compared with simple mechanical crushing or chemical degradation methods, the separation time is shortened by 30%-50%.

[0041] Quality Assurance: By employing the crushing process, optimized chemical degradation agent formulation, and reaction conditions of this invention, the damage to the glass fiber performance is minimized while effectively dissolving the resin matrix. The strength retention rate of the recovered glass fiber can reach over 90%, meeting the quality requirements for secondary processing and utilization. Furthermore, the yield of glass fibers with lengths of 1-10mm is high, with a significant proportion of fibers having a length of 3-7mm. The fiber size conformity rate is high, and the resulting fibers have a low breakage rate during subsequent utilization.

[0042] Cost reduction: The composite chemical degradation agent used in this invention can be recycled and reused through methods such as distillation, which reduces the cost of using chemical reagents; at the same time, the efficient separation process reduces processing time and energy consumption, further reducing the overall processing cost.

[0043] Environmental advantages: It reduces the generation of waste liquid, and the waste liquid generated can be effectively treated, thus reducing environmental pollution; it enables the recycling of glass fiber, reducing resource waste and meeting the requirements of sustainable development.

[0044] The present invention will be further illustrated by the following embodiments, but it should not be construed as the present invention being limited to these embodiments.

[0045] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in this technical field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0046] Example 1

[0047] Fiberglass can be recovered from decommissioned wind turbine blades through the following steps:

[0048] S1. Disassemble the retired wind turbine blades and remove non-glass fiber composite materials such as metal connectors and rubber sealing strips;

[0049] S2. The disassembled blades are coarsely crushed to obtain fragments with a size of about 10-20cm; then they are finely crushed in a hammer crusher to reduce the size of the fragments to less than 1cm, of which 70wt% are larger than 40 mesh, to obtain finely crushed material.

[0050] S3. The finely crushed material is placed in a degradation solution and subjected to degradation reaction at a temperature of 200°C. The liquid-to-solid ratio is 5 (unit: ml / g), and the reaction time is 25 min. After the reaction is completed, the material is filtered to obtain glass fiber filter residue.

[0051] The degradation solution is an aqueous solution of benzyl alcohol with added ferric chloride, wherein the volume of benzyl alcohol used is 90% of the total volume of benzyl alcohol and water, and the mass ratio of ferric chloride to finely crushed material is 1:20.

[0052] S4. Rinse the glass fiber filter residue three times with clean water in the washing tank until the pH value of the washing water is close to neutral. Each rinsing time is 10-15 minutes.

[0053] After cleaning, the glass fiber filter residue is spread evenly on a stainless steel tray and placed in a hot air circulating drying oven for drying. The drying temperature is 80℃ and the drying time is 4 hours. The moisture content of the dried glass fiber is less than 1%.

[0054] The degradation rate of this embodiment was found to be 100% upon testing.

[0055] Example 2

[0056] Fiberglass can be recovered from decommissioned wind turbine blades through the following steps:

[0057] S1. Disassemble the retired wind turbine blades and remove non-glass fiber composite materials such as metal connectors and rubber sealing strips;

[0058] S2. The disassembled blades are coarsely crushed to obtain fragments with a size of about 10-20cm; then they are finely crushed in a hammer crusher to make the fragment size less than 1cm, of which 80wt% are above 40 mesh, to obtain finely crushed material.

[0059] S3. The finely crushed material is placed in a degradation solution and subjected to degradation reaction at 300°C. The liquid-to-solid ratio is 10 (unit: ml / g), and the reaction time is 20 min. After the reaction is completed, the material is filtered to obtain glass fiber filter residue.

[0060] The degradation solution is an aqueous solution of benzyl alcohol with added zinc chloride, wherein the volume of benzyl alcohol used is 50% of the total volume of benzyl alcohol and water, and the mass ratio of zinc chloride to finely crushed material is 2:20.

[0061] S4. Rinse the glass fiber filter residue with clean water 4 times in the washing tank until the pH value of the washing water is close to neutral. Each rinsing time is 10-15 minutes.

[0062] After cleaning, the glass fiber filter residue is spread evenly on a stainless steel tray and placed in a hot air circulating drying oven for drying. The drying temperature is 90℃ and the drying time is 3 hours. The moisture content of the dried glass fiber is less than 1%.

[0063] The degradation rate of this embodiment was found to be 100% upon testing.

[0064] Example 3

[0065] Fiberglass can be recovered from decommissioned wind turbine blades through the following steps:

[0066] S1. Disassemble the retired wind turbine blades and remove non-glass fiber composite materials such as metal connectors and rubber sealing strips;

[0067] S2. The disassembled blades are coarsely crushed to obtain fragments with a size of about 10-20cm; then they are finely crushed in a hammer crusher to reduce the size of the fragments to less than 1cm, with 90wt% of the material being 40 mesh or larger, thus obtaining finely crushed material.

[0068] S3. The finely crushed material is placed in a degradation solution and subjected to degradation reaction at a temperature of 400°C. The liquid-to-solid ratio is 20 (unit: ml / g), and the reaction time is 15 min. After the reaction is completed, the material is filtered to obtain glass fiber filter residue.

[0069] The degradation solution is an aqueous solution of benzyl alcohol with added ferric chloride, wherein the volume of benzyl alcohol used is 10% of the total volume of benzyl alcohol and water, and the mass ratio of ferric chloride to finely crushed material is 1:20.

[0070] S4. Rinse the glass fiber filter residue 5 times with clean water in the washing tank until the pH value of the washing water is close to neutral. Each rinsing time is 10-15 minutes.

[0071] After cleaning, the glass fiber filter residue is spread evenly on a stainless steel tray and placed in a hot air circulating drying oven for drying. The drying temperature is 100℃ and the drying time is 4 hours. The moisture content of the dried glass fiber is less than 1%.

[0072] The degradation rate of this embodiment was found to be 100% upon testing.

[0073] Example 4

[0074] The procedure was carried out in accordance with Example 1, except that in step S3, the degradation reaction temperature was 150°C.

[0075] The degradation rate of this embodiment was found to be 100% upon testing.

[0076] Comparative Example 1

[0077] The procedure is carried out in accordance with Example 1, except that in step S2, coarse crushing is not performed, and fine crushing is performed directly.

[0078] Comparative Example 2

[0079] The procedure is carried out in accordance with Example 1, except that in step S3, the undersize material obtained from the fine crushed material in step S2 is taken and passed through a 40-mesh sieve for subsequent steps.

[0080] Comparative Example 3

[0081] The procedure is the same as in Example 1, except that:

[0082] In step S2, the material is finely crushed to reduce the size of the fragments to less than 1 cm, with 60 wt% of the fragments being larger than 40 mesh.

[0083] Comparative Example 4

[0084] The procedure is the same as in Example 1, except that:

[0085] In step S3, the volume of benzyl alcohol used in the benzyl alcohol aqueous solution is 5% of the total volume of benzyl alcohol and water.

[0086] The degradation rate of this comparative sample was found to be 67.23%.

[0087] Comparative Example 5

[0088] The procedure is the same as in Example 1, except that:

[0089] In step S3, the volume of benzyl alcohol used in the aqueous solution is 95% of the total volume of benzyl alcohol and water.

[0090] The degradation rate of this comparative sample was 94.21% as tested.

[0091] Comparative Example 6

[0092] The procedure is the same as in Example 1, except that:

[0093] In step S3, the mass ratio of ferric chloride to finely crushed material is 0.05:20.

[0094] The degradation rate of this comparative sample was found to be 83.43%.

[0095] Comparative Example 7

[0096] The procedure was carried out in accordance with Example 1, except that in step S3, the degradation solution was replaced with concentrated nitric acid with a concentration of 30 wt%, the degradation reaction was carried out at 180°C, and the reaction time was 2 h.

[0097] The degradation rate of this comparative example was 100% as tested.

[0098] Comparative Example 8

[0099] The procedure was carried out in accordance with Example 1, except that in step S3, ferric chloride in the degradation solution was replaced with potassium hydroxide.

[0100] The degradation rate of this comparative sample was found to be 96.56%.

[0101] Table 1

[0102]

[0103] In Table 1, "weight percentage of 3-7mm fiber" refers to the weight percentage of 3-7mm fiber in the 1-10mm fiber range.

[0104] Test method description:

[0105] Degradation rate: Weigh the crushed product M1, calcine at 600℃ for 30 min to obtain mass M2, and the resin content of the product is (M1-M2) / M1;

[0106] The degradation product m was calcined at 600℃ for 30 min to obtain the residual mass m1 of the degradation product. The degradation rate was calculated as (m-m1) / [m*(M1-M2) / M1]*100%.

[0107] Breakage rate: 100 recycled glass fibers were blown at a wind speed of 20 m / s for 5 hours, then heated at 200℃ for 5 hours, and then stirred in water for 5 hours. The number of broken fibers was observed. The proportion of broken fibers in the 100 recycled glass fibers was the breakage rate.

[0108] Glass fiber strength retention rate: tensile strength of recycled glass fiber / tensile strength of the original glass fiber used in the fabrication of wind turbine blades * 100%.

[0109] Average length of recycled glass fiber: Measure the length of 50 recycled clean glass fibers with calipers and take the average value.

[0110] As can be seen from the above experimental results, the method of the present invention for separating and recovering glass fibers from decommissioned wind turbine blades not only has a high degradation rate, a high glass fiber strength retention rate, and a low breakage rate, but also simultaneously achieves a high yield of 1-10mm long fibers and a high proportion of 3-7mm long fibers.

[0111] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method of isolating glass fibers from decommissioned wind turbine blades, characterized in that, The method comprises the following steps: S1, disassembling the retired wind power blade to remove the non-glass fiber composite material part; S2, coarsely crushing the disassembled blade to obtain fragments with a size of 10-20 cm; then finely crushing the fragments to make the size of the fragments less than 1 cm, and the proportion of fragments with a size of more than 40 meshes is greater than or equal to 70wt%, to obtain fine crushing materials; S3, placing the fine crushing materials in a degradation solution to perform a degradation reaction at a temperature of more than 150℃, the time of the degradation reaction is less than or equal to 30 minutes, and after the reaction is completed, filtering to obtain glass fiber residues; the degradation solution is a benzyl alcohol aqueous solution added with iron chloride and / or zinc chloride; in the benzyl alcohol aqueous solution, the proportion of the volume of benzyl alcohol in the total volume of benzyl alcohol and water is 10-90%; the ratio of the total mass of iron chloride and zinc chloride to the mass of the fine crushing materials is greater than or equal to 0.1:20; S4, cleaning and then drying the glass fiber residues to obtain pure glass fibers.

2. The method of claim 1, wherein, In step S3, the liquid-solid ratio of the degradation solution and the fine crushing materials is greater than or equal to 5, unit: ml / g.

3. The method of claim 2, wherein, In step S3, the liquid-solid ratio of the degradation solution and the fine crushing materials is 5-20, unit: ml / g.

4. The method of claim 2, wherein, The ratio of the total mass of iron chloride and zinc chloride to the mass of the fine crushing materials is 0.1-2:

20.

5. The method according to any one of claims 1 to 3, characterized in that, In step S3, the temperature of the degradation reaction is 200-400℃.

6. The method of claim 5, wherein, In step S3, the time of the degradation reaction is 5-30 minutes.

7. The method according to any one of claims 1 to 3, characterized in that, In step S4, the cleaning is multiple times of washing the glass fiber residues with clean water.

8. The method according to any one of claims 1 to 3, characterized in that, In step S4, the drying is drying to a water content of the glass fiber less than 1%.

9. The method of claim 8, wherein, The drying temperature of the drying is 80-100℃.

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