A wind turbine blade swelling method

Abstract

The application discloses a wind power blade swelling method, comprising the following steps: 1) cutting a retired wind power blade into several standard units, forming several micropores on the surface of each standard unit to form a microchannel array, then injecting a swelling aid into each micropore, and keeping the temperature at 50-90 DEG C for more than 0.5 hours to obtain a pretreated blade unit; 2) immersing the pretreated blade unit into a composite swelling system containing a main swelling agent, a swelling aid and a swelling promoter, performing a first swelling treatment at 60-100 DEG C and a second swelling treatment by heating to 100-300 DEG C; and taking out the blade unit after the step 2) swelling treatment from the composite swelling system, and collecting after standing at room temperature. The application constructs a pretreatment assisted two-stage gradient swelling integrated system, and realizes efficient, deep and uniform swelling of the blade through the synergistic effect of structure modification and the composite swelling system.

Description

Technical Field

[0001] This invention relates to the field of decommissioned wind turbine blade processing technology, and more specifically, to a method for swelling wind turbine blades. Background Technology

[0002] Wind turbine blades are the core components of wind turbines, primarily made of epoxy resin composites reinforced with glass fiber or carbon fiber. With the increase in installed wind power capacity nationwide, the number of retired blades will increase significantly. However, retired blades are difficult to degrade and become "white pollution" after retirement, leading to environmental pollution and resource waste. Recycling and reusing retired blades is an important technological approach to avoid environmental pollution and reduce resource waste. Currently, the main method for processing retired blades is high-temperature pyrolysis to remove resin and recycle fibers. However, existing methods involve high temperatures, causing thermal damage to the fibers, resulting in a significant decline in fiber performance, and failing to completely remove resin, thus limiting the reuse of recycled fibers.

[0003] Currently, some research has been conducted on pre-treatment of wind turbine blades by swelling in solvents. However, the core material of wind turbine blades is a thermosetting epoxy resin-based composite material, and the highly cross-linked structure formed after curing results in a tight bond between the resin and reinforcing fibers, posing significant challenges to subsequent separation processes. Current swelling technologies used for blade pretreatment have significant drawbacks: Limited swelling depth: Traditional single solvents can only act on the surface of the blade, and the penetration depth of the internal cross-linked resin is generally less than 10mm. This makes it impossible to achieve effective swelling of the entire blade resin, resulting in the need for additional high energy consumption in subsequent treatment to break the bonding force of the core resin. Low swelling efficiency: Traditional solvents and resins have low compatibility and lack targeted swelling promotion mechanisms. The short-term swelling rate of resins is usually less than 30%, and the swelling time is as long as 8-12 hours, which is difficult to meet the needs of large-scale processing. Poor swelling uniformity: The resin density and cross-linking degree vary in different regions of the blade (surface, core, and edge). Traditional swelling methods cannot adapt to this structural heterogeneity, and local imbalances such as excessive swelling of the surface and lack of swelling of the core are prone to occur, affecting the consistency of subsequent treatments. Summary of the Invention

[0004] Based on the aforementioned deficiencies in the background technology, the main objective of this invention is to provide a method for swelling wind turbine blades, breaking through the technical bottleneck of synergistic improvement in swelling depth, efficiency, and uniformity. This method achieves preliminary interface separation between the blade resin and fiber through efficient swelling, laying the foundation for subsequent resource utilization.

[0005] To achieve the above objectives, the present invention provides a method for swelling wind turbine blades, comprising the following steps: 1) Cut the retired wind turbine blades into several standard units, form several micropores on the surface of each standard unit to form a microchannel array, and then inject a swelling agent into each micropore and keep it at 50-90℃ for more than 0.5 hours to obtain the pretreated blade unit. 2) The pretreated blade unit is immersed in a composite swelling system containing a main swelling agent, a swelling aid and a swelling promoter, and undergoes a first-stage swelling treatment at 60-100℃ and a second-stage swelling treatment at 100-300℃. 3) Remove the blade unit after swelling in step 2) from the composite swelling system, let it stand at room temperature, and then collect it; The primary swelling agent is a swelling reagent with a Hansen solubility parameter (HSP) of 16.5-19.0 dispersion force, 4.5-10.0 polarity, and 4.0-12.0 hydrogen bond. The secondary swelling agent is one or more of benzyl alcohol, ethylene glycol, monobutyl ether, propylene glycol methyl ether, and diethylene glycol monobutyl ether. The swelling promoter is one or more of choline chloride, tetrabutylammonium bromide, urea, triethanolamine, tetrabutylammonium hydroxide, and hydroxyethyltributylammonium chloride.

[0006] Furthermore, in step 1), the maximum side length of the standard unit cell is no greater than 50 cm.

[0007] Furthermore, in step 1), several micropores on each surface are arranged in a square or rectangular dot pattern to form a microchannel array, with a spacing of 20-80 mm between adjacent micropores.

[0008] Further, in step 1), the micropore diameter is 0.8-5mm. When the micropore is formed on the surface perpendicular to the longest side of the standard unit, the micropore depth is greater than 1 / 10 of the length of the longest side of the standard unit; when the micropore is formed on the surface parallel to the longest side of the standard unit, the micropore depth is greater than 1 / 10 of the length of the perpendicular side of the corresponding surface.

[0009] Further, in step 1), a pulsed laser is used to perform a grid-like scan on the blade surface of each standard unit body, and micropores are formed in the center of each small grid, and several micropores form a microchannel array.

[0010] Furthermore, in step 1), the wavelength of the pulsed laser is 1064nm and the power is 50W.

[0011] Further, in step 1), the amount of swelling agent injected is 1 / 4 to 1 / 2 of the total amount of swelling agent used, by volume ratio, preferably kept at 50-90°C for 0.5-3 hours.

[0012] Further, in step 2), the main swelling agent is selected from a mixed solution of acetone and toluene, a mixed solution of dichloromethane and ethyl acetate, a mixed solution of methyl isobutyl ketone and isopropanol, a mixed solution of chloroform and butanone, and a mixed solution of N-methylpyrrolidone and dioxane.

[0013] Furthermore, in step 2), the amount of the main swelling agent is preferably enough to submerge the blade unit, and the liquid-to-solid ratio is not less than 5 ml / g, preferably 5-20 ml / g. Calculated by volume ratio, the amount of the auxiliary swelling agent is 1 / 20-1 / 10 of the main swelling agent, and the amount of the swelling promoter is 1%-5% of the main swelling agent.

[0014] Further, in step 2), the conditions for the first-stage swelling treatment include: holding at 60-100℃ for more than 0.5h, preferably 0.5-1.5h, and the conditions for the second-stage swelling treatment include: holding at 100-300℃ for more than 1h, preferably 1-3h.

[0015] The beneficial effects of this invention are as follows: The core of this invention lies in constructing an integrated system of "pretreatment assistance - two-stage gradient swelling," achieving efficient, deep, and uniform swelling of the blade through the synergistic effect of structural modification and the composite swelling system. The method provided by this invention achieves gradient-level deep swelling of wind turbine blades from the surface to the core: the core layer swelling penetration depth is ≥50mm, and the overall resin swelling rate is increased to over 45%; the swelling time is shortened: the single swelling treatment cycle is controlled within 4 hours, improving swelling efficiency; and the swelling uniformity of different areas of the blade is ensured: the difference in swelling rate between the surface and core layers is controlled within 10%, providing a stable pretreatment effect for subsequent resin-fiber separation. In summary, other features and advantages of the present invention will be described in detail through the following specific embodiments. Detailed Implementation

[0016] The following will clearly and completely describe the concept and technical effects of this application in conjunction with embodiments, so as to fully understand the purpose, features and effects of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the scope of protection of this application.

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] This invention provides a method for swelling wind turbine blades, comprising the following steps: 1) Cut the retired wind turbine blades into several standard units, form several micropores on the surface of each standard unit to form a microchannel array, then inject a swelling agent into each micropore, and keep it at 50-90℃ for more than 0.5 hours to obtain the pretreated blade unit. 2) The pretreated blade unit is immersed in a composite swelling system containing a main swelling agent, a swelling aid and a swelling promoter, and undergoes a first-stage swelling treatment at 60-100℃ and a second-stage swelling treatment at 100-300℃. 3) Remove the blade unit after swelling in step 2) from the composite swelling system, let it stand at room temperature, and then collect it; The primary swelling agent is a swelling reagent with a Hansen solubility parameter (HSP) of 16.5-19.0 dispersion force, 4.5-10.0 polarity, and 4.0-12.0 hydrogen bond. The secondary swelling agent is one or more of benzyl alcohol, ethylene glycol, monobutyl ether, propylene glycol methyl ether, and diethylene glycol monobutyl ether. The swelling promoter is one or more of choline chloride, tetrabutylammonium bromide, urea, triethanolamine, tetrabutylammonium hydroxide, and hydroxyethyltributylammonium chloride.

[0019] In this invention, in step 1), the decommissioned wind turbine blades are cut into standard unit cells, and a microchannel array is constructed. The required swelling agent is injected into the microchannels (micropores) to fully fill the microchannels and initially bond with the surrounding resin, forming a permeation guiding channel for the subsequent swelling medium. This invention pioneers a pretreatment method combining microchannels and swelling agents to construct directional permeation channels for the swelling medium, overcoming the bottleneck of traditional swelling's "surface barrier."

[0020] In step 2), an HSP-optimized composite swelling system is employed: by precisely controlling the Hansen solubility parameters of the main swelling agent, a swelling agent with HSP (dispersion power 16.5-19.0, polarity 4.5-10.0, hydrogen bonding 4.0-12.0) is selected to enhance the solvent's wetting ability on the surface resin; the swelling aid reduces the viscosity of the main solvent and increases the diffusion rate of the solvent on the leaf surface by strengthening penetration; the swelling promoter accelerates the swelling and expansion of the resin network by breaking the hydrogen bonds between resin molecules. Simultaneously, the primary swelling temperature is controlled between 60℃ and 100℃. During this stage, the synergistic effect between the components of the composite swelling system achieves an overall leaf swelling effect of over 30%; the secondary swelling stage is the core layer penetration swelling stage, resulting in uniform swelling depth. It achieves uniform distribution of the swelling system in the blade core layer, solving the uniformity problem of "excessive swelling on the surface and insufficient swelling in the core layer" in traditional swelling, keeping the difference in swelling rate between the surface and core layers within 10%, significantly improving the resin swelling rate, and shortening the swelling time by more than 50%.

[0021] Therefore, the method of the present invention, through pretreatment assistance and a two-stage gradient swelling design of "surface debonding - core penetration", adapts to the resin structural characteristics of different regions of the blade, ensuring both the interface debonding effect between the surface resin and the fiber and achieving deep swelling of the core resin, thus providing a comprehensive and uniform pretreatment basis for subsequent processing.

[0022] In some specific implementations, in step 1), the maximum side length of the standard unit is no greater than 50cm, preferably a cube whose length a, width b, and height c are all no greater than 50cm.

[0023] In some specific implementations, in step 1), the blade surface of the standard unit includes a surface perpendicular to the longest side (i.e., the surface where width b and height c are located) and a surface parallel to the longest side (i.e., the surface where length a and width b are located, and the surface where length a and height c are located), where the longest side is defined as length a.

[0024] In some specific embodiments, in step 1), several micropores on each surface are arranged in a square or rectangular dot pattern to form a microchannel array. The spacing between adjacent micropores is 20-80 mm, exemplarily 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm or other values ​​within the above range.

[0025] In some specific implementations, in step 1), the diameter of the micropore is 0.8-5mm. When the micropore is formed on the surface perpendicular to the longest side of the standard unit, the depth of the micropore is greater than 1 / 10 of the length of the longest side of the standard unit (i.e., length a). When the micropore is formed on the surface parallel to the longest side of the standard unit, the depth of the micropore is greater than 1 / 10 of the length of the perpendicular side of the corresponding surface (width b or height c).

[0026] In this invention, the forming process of micropores is not limited, and reference is made to existing technologies.

[0027] In this invention, the forming position of the micropores can be pre-positioned. In some specific embodiments, in step 1), a pulsed laser is used to perform a grid-like scan on the blade surface of each standard unit body, and micropores are formed in the center of each small grid. Several micropores form a microchannel array.

[0028] Preferably, the wavelength of the pulsed laser is 1064nm and the power is 50W.

[0029] In some specific implementations, in step 1), the amount of swelling agent injected accounts for 1 / 4 to 1 / 2 of the total amount of swelling agent used by volume, and micro-injection can be used.

[0030] In some specific embodiments, in step 2), the main swelling agent is selected from a mixed solution of acetone and toluene, a mixed solution of dichloromethane and ethyl acetate, a mixed solution of methyl isobutyl ketone and isopropanol, a mixed solution of chloroform and butanone, and a mixed solution of N-methylpyrrolidone and dioxane. Preferably, the two reagents in the above mixed solutions can be set to a certain volume ratio so that the Hansen solubility parameter (HSP) of the mixed solution meets the requirements of dispersion force 16.5-19.0, polarity 4.5-10.0, and hydrogen bonding 4.0-12.0. The preferred volume ratio is 3:1-1:3. This is only an example and is not limited to the following; the mixed solution is: A 1:1 volume ratio solution of acetone and toluene has a dispersion force of 16.75, a polarity of 5.9, and a hydrogen bond strength of 4.5. A mixed solution of dichloromethane and ethyl acetate in a volume ratio of 2:1 has a dispersion force of 17.4, a polarity of 5.8, and a hydrogen bond strength of 4.4. A mixed solution of methyl isobutyl ketone and isopropanol in a volume ratio of 3:1 has a dispersion force of 16.7, a polarity of 6.0, and a hydrogen bond strength of 5.7. A 1:1 volume ratio solution of chloroform and butanone has a dispersion force of 17.0, a polarity of 6.7, and a hydrogen bond strength of 5.1. In this invention, selecting the above-mentioned types of mixed solutions offers the following advantages: When choosing a mixed solution of acetone and toluene, the swelling effect is mild and will not excessively damage the cross-linking structure of epoxy resin. It can gradually soften the surface of epoxy materials, and the mixed solution has moderate volatility and no strong irritating residue.

[0031] When choosing a mixed solution of dichloromethane and ethyl acetate, the strong permeability of dichloromethane allows it to quickly penetrate the epoxy pores, while the hydrogen bonding of ethyl acetate helps to weaken the intermolecular forces, resulting in a faster swelling rate. Furthermore, the mixed solution has good fluidity and can penetrate into the interior of complex epoxy resin structures.

[0032] When a mixed solution of methyl isobutyl ketone and isopropanol is selected, the epoxy resin after swelling is in a soft and elastic state, without breakage or collapse, which is conducive to subsequent mechanical processing of mechanical materials or component extraction, and the mixed solution has no corrosive effect on metal substrates.

[0033] When using a mixture of chloroform and methyl ethyl ketone, the swelling effect on incompletely cured epoxy resin is significant. Moreover, this mixture is volatile, and the residual solvent can be quickly removed after the swelling treatment, without any subsequent cleaning burden.

[0034] In this invention, the aforementioned swelling aids do not possess strong swelling capacity themselves, but by adjusting the HSP of the composite system, the penetration effect can be enhanced to improve the swelling efficiency of the main swelling agent, and they can synergistically solubilize with the main swelling agent.

[0035] In this invention, the above-mentioned swelling promoters synergistically enhance the effects of other components in the composite swelling system through hydrogen bond competitive substitution, ionic electrostatics, coordination bonding, and other effects. The selection criteria for swelling promoters are as follows: reagents that can form strong interactions (electrostatics, coordination, hydrogen bond competition) with epoxy hydroxyl groups are preferred, and the promoters do not significantly change the HSP range of the original swelling system.

[0036] In some specific embodiments, in step 2), the amount of the main swelling agent is preferably enough to submerge the blade unit, the liquid-to-solid ratio is not less than 5 ml / g, preferably 5-20 ml / g, and the amount of the auxiliary swelling agent is 1 / 20-1 / 10 of the main swelling agent, and the amount of the swelling promoter is 1%-5% of the main swelling agent.

[0037] In some specific implementations, in step 2), the conditions for the primary swelling treatment include: holding at 60-100℃ for more than 0.5h, preferably 0.5-1.5h, and the conditions for the secondary swelling treatment include: holding at 100-300℃ for more than 1h, preferably 1-3h.

[0038] In this invention, step 3) is the stabilization stage after swelling: the blade unit is taken out from the swelling system and left to stand at room temperature, so that the excess swelling medium on the blade surface drips off naturally and is recovered. At the same time, the swelling resin inside the blade is kept in a stable swelling state to avoid the collapse of the swelling structure due to sudden pressure changes.

[0039] The present invention will be further illustrated by the following examples, but the present invention is not limited thereto.

[0040] Unless otherwise specified, the raw materials involved in this invention are all available from commercially available sources.

[0041] The method for testing the effect data is as follows: Overall swelling effect calculation: Calculated by the volume ratio before and after swelling, V after swelling / V before swelling.

[0042] Swelling difference between core and edge: Divide the core into five equal parts by making a small cut / mark along the longest side, and calculate the average volume increase ratio of the two ends / the volume increase ratio of the middle part.

[0043] Powder ratio: The percentage of the original blade mass in the swollen system after filtration.

[0044] Example 1 1. Pretreatment stage: Construction of leaf swelling channels Decommissioned GFRP blades (32% epoxy resin content) were cut into standard unit cells (20 x 10 x 10 cm). A pulsed laser (1064 nm wavelength, 50 W power) was used to perform a grid-like scan on the blade surface at 50 mm intervals. The two surfaces perpendicular to the longest side (with the greatest depth) served as depth-constructing channels. On these surfaces, micropores with a depth of 1 / 10 of the longest side length (2 cm) and a diameter of 1.2 mm were formed at the center of each grid. On the other four surfaces of the blade (parallel to the longest side), micropores with a depth of 1 / 10 of the perpendicular side length (1 cm) and a diameter of 1.2 mm were formed at the center of each grid. These micropores formed a microchannel array. The final mass of the perforated blade unit cell was 2823 g.

[0045] Subsequently, half the required volume of swelling agent is injected into the microchannel using microinjection technology, and the channel is kept at 60°C for 1 hour to allow this portion to fully fill the microchannel and initially combine with the surrounding resin, forming a permeation guiding channel for the subsequent swelling medium. 2. Primary surface swelling stage: interfacial debonding and swelling The pretreated blade unit was immersed in a "main solvent-co-solvent" composite swelling system. In this composite swelling system, the main swelling agent was a 1:1 volume ratio of acetone and toluene mixed solution (dispersion power 16.75, polarity 5.9, hydrogen bond 4.5), and the amount used was to submerge the block, with a liquid-to-solid ratio of 5:1 ml / g. The co-swelling agent was ethylene glycol monobutyl ether, and the total amount used was 1 / 12 of the volume of the main swelling agent (a portion of which had already been injected, and this portion was the remaining portion, with a volume ratio of 1:1 between the two portions). The swelling promoter was urea, and the amount used was 3 / 100 of the volume of the main swelling agent.

[0046] The primary swelling agent enhances the solvent's ability to wet the surface resin, while the secondary swelling agent reduces the viscosity of the primary swelling agent and increases the solvent's diffusion rate on the leaf surface by strengthening penetration. The swelling promoter accelerates the swelling and expansion of the resin network by breaking the hydrogen bonds between resin molecules. The swelling temperature during the first swelling stage is controlled at 60℃, and the heat treatment lasts for 0.8 hours.

[0047] 3. Secondary core layer permeation and swelling stage: uniform swelling at a certain depth After the first stage of swelling is completed, the temperature of the reactor is raised to 120°C, the pressure is kept stable, and the reactor is kept at this temperature for 1 hour. 4. Stabilization phase after swelling The blade unit is filtered out of the swelling system and left to stand at room temperature for 30 minutes to allow excess swelling medium on the blade surface to drip off and be recovered naturally. At the same time, the swelling resin inside the blade is kept in a stable swelling state to prevent the swelling structure from collapsing due to sudden pressure changes.

[0048] Example 2 The difference from Example 1 is that: the center of each grid obtained on the two surfaces perpendicular to the longest side has a microhole with a forming depth of 1 / 8 of the length of the longest side and a hole diameter of 1.2 mm; the center of each grid obtained on the other four surfaces of the blade (the surfaces parallel to the longest side) has a microhole with a forming depth of 1 / 8 of the length of the perpendicular side of the corresponding surface and a hole diameter of 1.2 mm. The final blade mass of the perforated blade unit is 2401 g.

[0049] The main swelling agent is a mixed solution of dichloromethane and ethyl acetate in a volume ratio of 2:1, with a dispersion power of 17.4, polarity of 5.8, hydrogen bonding of 4.4, and a liquid-to-solid ratio of 8:1 with the solid. The cosolvent is propylene glycol methyl ether, and the total amount used is 1 / 14 of the volume of the main swelling agent. The accelerator is tetrabutylammonium bromide, and the dosage is 4 / 100 of the volume of the main swelling agent; The conditions for the first stage of swelling were: 80℃, reaction time 0.8h; The conditions for the second swelling stage are: heating to 150℃ and reacting for 1 hour.

[0050] Example 3 The difference from Example 1 is that: the center of each grid obtained on the two surfaces perpendicular to the longest side has a microhole with a forming depth of 1 / 4 of the length of the longest side and a hole diameter of 2.1 mm; the center of each grid obtained on the other four surfaces of the blade (the surfaces parallel to the longest side) has a microhole with a forming depth of 1 / 4 of the length of the perpendicular side of the corresponding surface and a hole diameter of 2.1 mm. The final blade mass of the perforated blade unit is 2272 g.

[0051] The main swelling agent is a mixed solution of methyl isobutyl ketone and isopropanol in a volume ratio of 3:1, with a dispersion force of 16.7, polarity of 6.0, and hydrogen bonding of 5.7; the liquid-to-solid ratio with the solid is 7:1. The cosolvent is diethylene glycol monobutyl ether, and the total amount used is 1 / 15 of the volume of the main swelling agent. The amount used in step 1 accounts for 1 / 3 of the amount used in step 2. The accelerator is tetrabutylammonium bromide, and its dosage is 3 / 100 of the volume of the main swelling agent.

[0052] The conditions for the first stage of swelling were: 75℃, reaction time 0.6h; The conditions for the second swelling stage are: heating to 160℃ and reacting for 1.2 hours.

[0053] Comparative Example 1 Without performing the pretreatment in step 1 (without drilling), the cut standard blade unit is directly immersed in the composite swelling system, and the rest is the same as in Example 1.

[0054] Comparative Example 2 The main swelling agent used was DMF (dimethylformamide) + DMSO (dimethyl sulfoxide) (volume ratio 1:1). The HSP parameters (weighted) were: dispersion force δD≈17.9, polarity δP≈15.05, hydrogen bond δH≈10.75, and the rest were the same as in Example 1.

[0055] Comparative Example 3 The main swelling agent used was ethylene glycol methyl ether + glycerol (volume ratio 3:2). The HSP parameters (weighted) were: δd≈17.7, δp≈10.5, δh≈23.58 (swelling was only obvious on the surface). The rest were the same as in Example 1.

[0056] Comparative Example 4 The first swelling stage was not set, and the swelling was carried out directly at 120°C for 1 hour. The rest was the same as in Example 1.

[0057] Comparative Example 5 The second swelling stage was changed to a reaction at 220°C for 5 hours, with the rest being the same as in Example 1. If this stage is too long, it can easily lead to the material becoming powdery, and at the same time, it can severely damage the swelling reagent, affecting its recycling.

[0058] Comparative Example 6 The standard unit obtained by cutting was immersed in nitric acid (concentration of 30%) and reacted at 60℃ for 0.8h and then at 120℃ for 1h.

[0059] In the above embodiments and comparative examples, the composite swelling system was recycled and reused 5 times, and the swelling effect was as follows:

[0060] In summary, the above embodiments demonstrate the following advantages of the present invention: Significantly improved swelling depth: The core layer swelling penetration depth is large, covering the entire thickness range of the blade, completely solving the technical defect of traditional swelling that only acts on the surface layer; Significantly improved swelling efficiency: The single swelling treatment cycle is only 3.5-4 hours, the resin swelling rate is high, and the efficiency is more than twice that of the traditional process; Excellent swelling uniformity: The difference in swelling rate between the blade surface and core is ≤10%, and the swelling effect in different areas is highly consistent, ensuring the stability and reliability of subsequent treatment; Wide material compatibility: Applicable to both GFRP and CFRP, two mainstream wind turbine blade materials, and has strong universality; Green and environmentally friendly: The swelling system contains no strong acid or strong alkali components, reducing solvent pollution and resource waste.

[0061] Although the present invention has been described in detail through the preferred embodiments described above, it should be understood that the above description should not be considered as a limitation of the present invention. Those skilled in the art will understand that modifications or adjustments can be made to the present invention based on the teachings of this specification. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A method for swelling wind turbine blades, characterized in that, Includes the following steps: 1) Cut the retired wind turbine blades into several standard units, form several micropores on the surface of each standard unit to form a microchannel array, then inject a swelling agent into each micropore, and keep it at 50-90℃ for more than 0.5 hours to obtain the pretreated blade unit. 2) The pretreated blade unit is immersed in a composite swelling system containing a main swelling agent, a swelling aid and a swelling promoter, and undergoes a first-stage swelling treatment at 60-100℃ and a second-stage swelling treatment at 100-300℃. 3) Remove the blade unit after swelling in step 2) from the composite swelling system, let it stand at room temperature, and then collect it; The primary swelling agent is a swelling reagent with Hansen solubility parameters of dispersion force 16.5-19.0, polarity 4.5-10.0, and hydrogen bonding 4.0-12.0; the secondary swelling agent is one or more of benzyl alcohol, ethylene glycol, monobutyl ether, propylene glycol methyl ether, and diethylene glycol monobutyl ether; and the swelling promoter is one or more of choline chloride, tetrabutylammonium bromide, urea, triethanolamine, tetrabutylammonium hydroxide, and hydroxyethyltributylammonium chloride.

2. The wind turbine blade swelling method according to claim 1, characterized in that, In step 1), the maximum side length of the standard unit cell is no more than 50 cm.

3. The wind turbine blade swelling method according to claim 1, characterized in that, In step 1), several micropores on each surface are arranged in a square or rectangular dot pattern to form a microchannel array, with a spacing of 20-80 mm between adjacent micropores.

4. The wind turbine blade swelling method according to any one of claims 1-3, characterized in that, In step 1), the micropore diameter is 0.8-5mm. When the micropore is formed on the surface perpendicular to the longest side of the standard unit, the micropore depth is greater than 1 / 10 of the length of the longest side of the standard unit; when the micropore is formed on the surface parallel to the longest side of the standard unit, the micropore depth is greater than 1 / 10 of the length of the perpendicular side of the corresponding surface.

5. The wind turbine blade swelling method according to claim 1, characterized in that, In step 1), a pulsed laser is used to perform a grid-like scan on the blade surface of each standard unit, and micropores are formed in the center of each small grid. Several micropores form a microchannel array.

6. The wind turbine blade swelling method according to claim 5, characterized in that, In step 1), the wavelength of the pulsed laser is 1064nm and the power is 50W.

7. The wind turbine blade swelling method according to claim 1, characterized in that, In step 1), the amount of swelling aid injected is 1 / 4 to 1 / 2 of the total amount of swelling aid used, by volume ratio, and the solution is kept at 50-90℃ for 0.5-3 hours.

8. The wind turbine blade swelling method according to claim 1, characterized in that, In step 2), the main swelling agent is selected from a mixed solution of acetone and toluene, a mixed solution of dichloromethane and ethyl acetate, a mixed solution of methyl isobutyl ketone and isopropanol, a mixed solution of chloroform and butanone, and a mixed solution of N-methylpyrrolidone and dioxane.

9. The wind turbine blade swelling method according to claim 1, characterized in that, In step 2), the amount of the main swelling agent should be enough to submerge the blade unit, and the liquid-to-solid ratio should not be less than 5 ml / g. By volume ratio, the amount of the auxiliary swelling agent is 1 / 20 to 1 / 10 of the main swelling agent, and the amount of the swelling promoter is 1% to 5% of the main swelling agent.

10. The wind turbine blade swelling method according to claim 1, characterized in that, In step 2), the conditions for the first-stage swelling treatment include: holding at 60-100℃ for more than 0.5 hours, and the conditions for the second-stage swelling treatment include: holding at 100-300℃ for more than 1 hour.

11. The wind turbine blade swelling method according to claim 10, characterized in that, In step 2), the conditions for the first-stage swelling treatment include: holding at 60-100℃ for 0.5-1.5h, and the conditions for the second-stage swelling treatment include: holding at 100-300℃ for 1-3h.

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