Methods for preparing fiber-reinforced materials
By separating and fragmenting fiber-reinforced composite materials from retired wind turbine blades, the problem of difficult recycling of reinforcing fiber materials has been solved, enabling the recycling of fiber materials and low-cost manufacturing of new blades.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- VESTAS WIND SYSTEMS AS
- Filing Date
- 2025-01-02
- Publication Date
- 2026-07-31
AI Technical Summary
The reinforcing fiber materials in existing wind turbine blades are difficult to effectively recycle and reuse after their service life, resulting in resource waste and increased costs.
By separating fiber-reinforced composite materials from decommissioned or damaged wind turbine blades, breaking them into multiple fiber elements using chemical or mechanical methods, and restoring the integrity of the fibers by dissociating the fluid-degrading binder, the fibers can then be used to manufacture new blades.
This enables the effective recycling and reuse of reinforcing fiber materials, reduces the production cost of new blades, and minimizes resource waste.
Smart Images
Figure CN122497801A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates generally to wind turbine blades, and more specifically to a method for preparing fiber-reinforced materials from wind turbine blades. Background Technology
[0002] Modern wind turbine blades typically comprise a substantially hollow outer shell supported by one or more spars. The shell and spars can be formed at least partially from composite materials due to their advantageous strength-to-weight ratio. For example, a longitudinally extending spars can include one or more longitudinally extending spars caps configured to withstand bending loads experienced by the blade during operation. Therefore, such spars caps can include multiple longitudinally extending reinforcing fibers to provide the required stiffness. However, the manufacture of reinforcing fibers (e.g., carbon fibers) can be relatively difficult and expensive.
[0003] Blade design practices typically mean that structural components of wind turbine blades are designed with a safety factor that allows them to withstand loads far exceeding the loads they actually experience during use. Therefore, for example, the reinforcing fibers of a sparsity structure can have a lifespan far exceeding the expected lifespan of a wind turbine blade. This means that the reinforcing fibers may still be fully usable when the blade is decommissioned at the end of its life.
[0004] Furthermore, in some cases, wind turbine blades may be decommissioned due to damage that does not affect the spars structure or the reinforcing fibers. Therefore, even if the entire blade is decommissioned, the reinforcing fibers may still be fully usable. The same applies to the reinforcing fibers in test blades or blade components that are discarded before use due to manufacturing errors or shipping damage.
[0005] Therefore, there is the possibility of reusing reinforcing fibers previously included in wind turbine blades for new applications. It is in this context that the present invention was developed.
[0006] WO 2021 / 191296 discloses a method for preparing wind turbine blades for recycling, the method being carried out by dividing the blades into wind turbine blade components and crushing and / or grinding each wind turbine blade component separately. Summary of the Invention
[0007] In a first aspect of the invention, a method for preparing a fiber-reinforced material from a wind turbine blade is provided. The method includes providing a used wind turbine blade extending longitudinally between a root end and a tip end and including a blade shell. The used blade also includes a longitudinally extending sparsity structure configured to support the shell. The sparsity structure is at least partially formed of a fiber-reinforced composite material comprising a plurality of longitudinally extending reinforcing fibers oriented such that the fiber direction of each reinforcing fiber is substantially parallel to the longitudinal axis of the blade. The method further includes separating the fiber-reinforced composite from the used wind turbine blade. The fiber-reinforced composite comprises a plurality of longitudinally extending reinforcing fibers. The method further includes fragmenting the fiber-reinforced composite into a plurality of fiber elements. Each fiber element includes at least one longitudinally extending reinforcing fiber, and each fiber element extends longitudinally in a direction substantially parallel to the fiber direction of the corresponding at least one longitudinally extending reinforcing fiber.
[0008] In some examples, the used wind turbine blades may be retired wind turbine blades that have reached the end of their service life. Alternatively, in some other examples, the used wind turbine blades may be damaged retired wind turbine blades. Alternatively, the used wind turbine blades may be blade production waste components. Furthermore, in some other examples, the used wind turbine blades may be test blades. It should be understood that in each of these examples, as previously described in the background section, the reinforcing fibers may still be fully usable despite the blade being decommissioned or discarded as a whole.
[0009] The spar structure may include one or more spar caps. Therefore, the fiber-reinforced composite may be at least a portion of the spar cap, and the longitudinally extending reinforcing fibers may be the reinforcing fibers of the spar cap. The spar cap may include a plurality of substantially unidirectional reinforcing fibers arranged in a highly ordered manner. Therefore, the fiber-reinforced composite may include a plurality of substantially unidirectional reinforcing fibers arranged in a highly ordered manner. Thus, this method is particularly advantageous for preparing fiber-reinforced materials from wind turbine blade spar caps.
[0010] In some preferred examples, the longitudinally extending reinforcing fibers may be carbon fibers, and the spar structure may therefore be at least partially formed of carbon fiber reinforced composite material. Thus, in some examples, the spar cap may be at least partially formed of carbon fiber reinforced composite material, such as carbon fiber reinforced plastic (CFRP). Consequently, the fiber-reinforced composite separated from the wind turbine blade in use may include carbon fibers, and the fiber-reinforced composite may be a carbon fiber reinforced composite. Therefore, examples of the methods described herein can be used to prepare carbon fiber reinforced materials, particularly longitudinally extending carbon reinforcing fibers, from wind turbine blades in use, and more specifically from the spar caps of wind turbine blades in use.
[0011] In some examples, the sparsity structure may be bonded to the inner surface of the blade shell. Therefore, separating the fiber-reinforced composite from an existing wind turbine blade may include separating the fiber-reinforced composite from the inner surface of the blade shell, for example by cutting or chemically separating an adhesive layer that bonds the sparsity structure to the inner surface.
[0012] For example, the sparsity structure can be bonded to the inner surface of the blade casing using an epoxy resin or adhesive. Therefore, separating the fiber-reinforced composite from an existing wind turbine blade may include applying a dissociation fluid to the interface between the sparsity cap and the inner surface of the blade casing to at least partially degrade the epoxy resin or adhesive. In such examples, the dissociation fluid may be a swelling fluid. This method is particularly suitable for examples where the epoxy resin or adhesive is an amine-cured epoxy resin. In some examples, the swelling fluid may contain formic acid.
[0013] In some other examples, the spar cap can be bonded to the inner surface of the blade shell using a chemically dissociable resin such as Aditya Birla Recyclamine. In such examples, applying a dissociative fluid to the bond between the spar cap and the inner surface of the blade shell chemically dissociates the resin, thereby facilitating the separation of the fiber-reinforced composite from the wind turbine blade in use.
[0014] Alternatively, in some examples, the sparsity structure may be incorporated into the blade shell such that a portion of the blade shell overlaps at least a portion of the sparsity structure. In such examples, separating the fiber-reinforced composite from an existing wind turbine blade (e.g., by cutting) may include separating at least a portion of the sparsity structure and the overlapping portion of the blade shell from the remainder of the blade shell (i.e., the body portion). Thus, in some examples, the fiber-reinforced composite may include at least a portion of the sparsity cap and at least a portion of the overlapping portion of the blade shell.
[0015] Alternatively, in some other examples, the sparsity structure may be at least partially integrated into the blade casing. In such examples, separating the fiber-reinforced composite from an existing wind turbine blade may include separating the fiber-reinforced composite from the blade casing. For example, the sparsity structure may include one or more sparsity caps integrated into the blade casing. Therefore, separating the fiber-reinforced composite from an existing wind turbine blade may include separating at least a portion of the sparsity cap from the blade casing.
[0016] In some examples, separating the fiber-reinforced composite from an existing wind turbine blade may include cutting at least a portion of the sparsity structure from the blade shell. For example, the method may include cutting through a laminated layer across the blade shell to release at least a portion of the sparsity cap, thereby obtaining a separate fiber-reinforced composite. Alternatively, separating the fiber-reinforced composite from an existing wind turbine blade may include a chemical separation process as previously described in the example of the sparsity cap being bonded to the blade shell. In such an example, a dissociation fluid may be applied to the blade shell to at least partially degrade (e.g., swell) the epoxy body material in the blade shell, thereby releasing the sparsity cap from the blade shell to obtain a separate fiber-reinforced composite.
[0017] In some examples, splitting a fiber-reinforced composite into multiple fiber elements may include longitudinally splitting the fiber-reinforced composite in a direction substantially parallel to the fiber direction of the reinforcing fibers in the composite. For example, splitting the fiber-reinforced composite may include driving a blade or splitting wedge through the fiber-reinforced composite to split the fiber-reinforced composite into individual fiber elements, each fiber element comprising at least one longitudinally extending reinforcing fiber. The splitting method may be advantageous for obtaining fiber elements in which as many reinforcing fibers as possible retain their longest possible length, because the fiber-reinforced composite is split along the fiber direction, meaning the reinforcing fibers are not damaged and retain their full length.
[0018] In some examples, the fiber-reinforced composite may comprise a multilayer fiber-reinforced composite pultrusion attached together in a stack. Therefore, a split fiber-reinforced composite may comprise splitting one pultrusion in the stack into multiple fiber elements. The pultrusion may comprise multiple substantially unidirectional, longitudinally extending reinforcing fibers in a highly ordered or regular arrangement. The bond strength between the fibers in the pultrusion (i.e., matrix strength) may be relatively lower than the strength of the fibers themselves, and therefore the fiber-reinforced composite can be split relatively easily by longitudinally splitting it through the pultrusion.
[0019] Furthermore, such a splitting method is particularly advantageous in examples where the fiber-reinforced composite includes one or more fiber sandwiches between adjacent fiber-reinforced composite pultruded layers in a stack. For example, the fiber sandwiches may comprise biaxial fiber materials. Therefore, the region between adjacent pultruded parts in the stack may be more resistant to longitudinal splitting than the pultruded parts themselves. Consequently, in some examples, splitting one or more pultruded parts in a direction substantially parallel to the fiber direction of the reinforcing fibers in the respective pultruded part may be preferred over splitting through the sandwiches.
[0020] In some examples where the fiber-reinforced composite includes multiple fiber-reinforced composite pultruded layers attached together in a stack, the split fiber-reinforced composite may include multiple pultruded parts in the stack, such that the fiber-reinforced composite is broken into multiple fiber elements, each fiber element including multiple reinforcing fibers from the multiple pultruded parts. For example, each pultruded part in the stack may have an upper surface and a lower surface, and the pultruded parts may be arranged vertically to each other in the stack such that the upper and lower surfaces of adjacent pultruded parts are attached together. The fiber-reinforced composite may be longitudinally split by blades or splitting wedges oriented perpendicular to the upper and lower surfaces of the pultruded parts. Thus, the resulting fiber elements may include portions of a stack of multiple different pultruded parts.
[0021] Furthermore, in some examples, the pultruded stack may include an adhesive or resin interlayer between adjacent pultruded parts. Optionally, such a stack may include fiber reinforcement material between adjacent pultruded parts. A split fiber-reinforced composite may include splitting adjacent pultruded parts and their respective interlayers such that the fiber-reinforced composite is fragmented into multiple fiber elements, each fiber element comprising a portion of reinforcing fibers from multiple adjacent pultruded parts and a portion of the respective interlayer between them. Thus, the resulting fiber elements may comprise a stack of portions of multiple different pultruded parts and a portion of the respective interlayer (optionally including fiber reinforcement material) between adjacent pultruded parts.
[0022] In some examples, the fiber-reinforced composite may comprise a multilayer fiber-reinforced composite pultrusion attached together in a stack, and the split fiber-reinforced composite may comprise splitting at least one pultrusion from an adjacent pultrusion in the stack. For example, the fiber-reinforced composite may be longitudinally split by a blade or splitting wedge aligned with a sandwich or interface plane between adjacent pultrusions in the stack. Thus, in such examples, the fiber element may comprise reinforcing fibers from a single pultrusion.
[0023] In some examples, fragmenting the fiber-reinforced composite may include cutting the composite along a cutting axis substantially parallel to the fiber direction of the reinforcing fibers within the composite. For example, in some examples, the method may include cutting the fiber-reinforced composite with a band saw or circular saw. Such methods facilitate the use of standard, existing tools in blade manufacturing and / or recycling facilities.
[0024] In some examples, each fiber element may include at least one reinforcing fiber embedded in a polymer matrix material. Therefore, in some examples, each fiber element may be a composite component. For example, in some examples, each fiber element may include at least a portion of at least one fiber-reinforced composite pultrusion. Thus, each fiber element may include a plurality of substantially unidirectional, longitudinally extending reinforcing fibers.
[0025] In some examples, the method may further include attaching a plurality of fiber elements together to form a composite fiber element comprising a plurality of reinforcing fibers. In such examples, the fiber elements are preferably attached to each other such that the fiber orientation of one or more reinforcing fibers in each fiber element is substantially parallel to the fiber orientation of one or more reinforcing fibers in each other fiber element of the composite fiber element. Thus, the composite fiber element may comprise a plurality of substantially unidirectional, longitudinally extending reinforcing fibers.
[0026] In some examples, the blade shell may include a blade shell polymer resin matrix. In such examples, separating the fiber-reinforced composite from a used wind turbine blade may include applying a dissociative fluid to the blade shell to at least partially degrade the blade shell polymer resin matrix. This allows the fiber-reinforced composite to be released from the used wind turbine blade, or the bond between the blade shell and the fiber-reinforced composite to be weakened, thereby facilitating the release of the fiber-reinforced composite from the used wind turbine blade.
[0027] In some examples, the fiber-reinforced composite may include reinforcing fibers anchored in a polymeric resin matrix. In such examples, fragmenting the fiber-reinforced composite may include applying a dissociation fluid to the fiber-reinforced composite to at least partially degrade the polymeric resin matrix, thereby releasing one or more reinforcing fibers from the polymeric resin matrix. It should be understood that in such examples, the fiber-reinforced composite may be fragmented into multiple fiber elements, wherein each fiber element is an individual reinforcing fiber.
[0028] In such examples, the dissociation fluid can be a swelling fluid. For instance, the fiber-reinforced composite may include reinforcing fibers embedded in a thermosetting epoxy resin having a cross-linked network structure, and the swelling fluid may swell the thermosetting epoxy resin in the fiber-reinforced composite. This approach is particularly suitable for examples where the thermosetting epoxy resin is an amine-cured epoxy resin. In some examples, the swelling fluid may contain formic acid.
[0029] In some other examples, the fiber-reinforced composite may include reinforcing fibers embedded in a chemically dissociable resin such as Aditya Birla Recyclamine. In such examples, a dissociation fluid is applied to the chemically dissociable resin of the fiber-reinforced composite, thereby releasing one or more reinforcing fibers.
[0030] In some examples, the fiber-reinforced composite may include a multilayer fiber-reinforced composite pultrusion attached together in a stack, and breaking up the fiber-reinforced composite may include applying a dissociation fluid to the joint area between adjacent pultrusions to separate the adjacent pultrusions from each other.
[0031] For example, fiber-reinforced composite pultrusions can be bonded together by epoxy resin or adhesive between adjacent pultrusions. Therefore, applying a dissociation fluid to the bonding area can at least partially degrade the epoxy resin or adhesive, thereby facilitating the separation of the pultrusions. Similarly, in such examples, the dissociation fluid can be a swelling fluid. For example, fiber-reinforced composite pultrusions can be bonded together by an epoxy matrix material having a cross-linked network structure, and the swelling fluid can swell the epoxy matrix material to facilitate the separation of the fiber-reinforced composite pultrusions. Such a method is particularly suitable for examples where the epoxy matrix material is an amine-cured epoxy resin. In some examples, the swelling fluid may contain formic acid.
[0032] In some other examples, fiber-reinforced composite pultrusions can be attached together in a stack using a chemically dissociable resin such as Aditya Birla Recyclamine. In such examples, applying a dissociative fluid to the bonding area between adjacent pultrusions chemically dissociates the resin, thereby facilitating the separation of the fiber-reinforced composite pultrusions.
[0033] In some examples, the method may further include winding the fiber element after it has been shredded from the fiber-reinforced composite. Thus, the fiber element can be reconfigured into a roll or spool after being shredded from the fiber-reinforced composite for transport or storage. Transporting and / or storing the fiber element as a roll advantageously maintains the structural integrity of the reinforcing fibers within the fiber element, while reducing the size or space occupied by the fiber element for easier handling and more space-efficient storage. It should be understood that in some examples, the fiber element may be a composite component, such as part of one or more fiber-reinforced composite pultrusions. Therefore, the method may include winding such a composite component. Furthermore, it should be understood that in some examples, the fiber element may be part of a composite fiber element. Therefore, the method may include winding a composite fiber element comprising multiple fiber elements. In some other examples, as previously described, each fiber element may be a separate reinforcing fiber. Therefore, in such examples, the method may include winding or wrapping one or more separate reinforcing fibers.
[0034] In some examples, the fiber elements can be wound into rolls or spools with a diameter greater than 1 m, preferably greater than 1.5 m, and more preferably greater than 2 m. This helps to ensure that the structural integrity of the reinforcing fibers of the respective fiber elements is maintained without introducing kinks or other discontinuities, allowing the reinforcing fibers to maintain their longitudinal stiffness.
[0035] In some examples, the length of each of the plurality of fiber elements may be at least 15 m, preferably at least 25 m, and more preferably at least 35 m. Thus, the method may advantageously include breaking the fiber-reinforced composite into fiber elements comprising reinforcing fibers with a length of at least 15 m, preferably at least 25 m, and more preferably at least 35 m. In some examples, the plurality of fiber elements may comprise one or more fiber elements with a length of at least 50 m, preferably at least 60 m, and more preferably at least 70 m. Therefore, the method may advantageously include breaking the fiber-reinforced composite into one or more fiber elements comprising reinforcing fibers with a length of at least 50 m, preferably at least 60 m, and more preferably at least 70 m.
[0036] In some examples, the method may further include reactivating the fiber element after it has been fragmented from the fiber-reinforced composite. Reactivating the fiber element may be particularly suitable for examples where the fiber element is a composite component comprising at least one reinforcing fiber embedded in a polymer matrix material. For example, reactivating the fiber element may include grinding at least a portion of the fiber element to increase its surface roughness, thereby improving the adhesion of the fiber element to the resin or adhesive during subsequent manufacturing processes involving the fiber element. In some other examples, reactivating the fiber element may additionally or alternatively include a chemical etching process of the fiber element, or the application of a primer or slurry to the fiber element. In some examples, reactivating the fiber element may include placing the fiber element in a dissociative fluid, for example to remove chemically dissociable resins, such as residual adhesives or resin in the polymer matrix of a blade housing; cleaning or roughening the polymer resin matrix of the fiber element; or cleaning the surface of the reinforcing fiber.
[0037] In some examples, the method may further include applying resin to the fiber elements and optionally curing the resin. For example, as previously described, each fiber element may be a composite component comprising at least one reinforcing fiber embedded in a polymer matrix material. During the process of breaking the fiber-reinforced composite into multiple fiber elements, the polymer resin matrix material of the fiber elements may be fragmented or split. Therefore, any such damaged polymer resin matrix material can be replaced by applying resin to the fiber elements and curing the resin.
[0038] Alternatively, in some examples, each fiber element may be a separate reinforcing fiber, as previously described. Therefore, applying resin to the fiber elements may include coating the reinforcing fibers with resin, such as a thermosetting polymer resin. For example, resin may be applied to the fiber elements (i.e., the reinforcing fibers) during a pultrusion process, wherein the fiber elements are resin-coated and pulled through a die to form a new fiber-reinforced composite pultruded part.
[0039] In another aspect of the invention, a method for manufacturing a wind turbine blade is provided. The method includes preparing a fiber-reinforced material according to any example herein. The method further includes arranging one or more layers of blade shell material in a mold, and arranging one or more fiber elements in the mold. The method further includes supplying resin to the blade shell material and fiber elements in the mold. The method further includes at least partially curing the resin to bond the one or more fiber elements to the one or more layers of blade shell material.
[0040] In some examples, the one or more blade shell materials may include layers of fiber-reinforced material, such as biaxial glass fiber reinforcement or chopped strand mat. In some examples, the one or more fiber elements may be composite components comprising at least one reinforcing fiber embedded in a cured polymer matrix material. Thus, relative to methods of manufacturing wind turbine blades, the fiber elements may be prefabricated composite components. In some examples, the fiber elements may be part of a composite fiber element, and the method may include arranging the composite fiber element in a mold.
[0041] In some other examples, the one or more fiber elements may be individual reinforcing fibers arranged in a die within a pultrusion. For example, in an example where the fiber element is an individual reinforcing fiber, the fiber element may be remanufactured into a new pultrusion, and such a pultrusion may then be arranged in a die to form at least a portion of a new wind turbine blade. Attached Figure Description
[0042] The invention is described below by way of non-limiting example and with reference to the accompanying drawings, wherein: Figure 1 This is a schematic exploded view of a wind turbine blade already in use; Figure 2 This is a schematic perspective view of an example of a wing spars cap; Figure 3 The fiber-reinforced composite separated from the blade is shown; Figure 4 An example of cutting a fiber-reinforced composite into multiple fiber elements is shown; Figures 5 to 7 An example of splitting a fiber-reinforced composite into multiple fiber elements is shown; Figure 8 An example is shown of fracturing a fiber-reinforced composite by applying a dissociation fluid to the bonding region between pultruded parts of the fiber-reinforced composite; Figure 9 Several cross-sectional views of an example of a composite fiber element formed by multiple fiber elements attached together are shown; Figure 10An example is shown where a fiber-reinforced composite is immersed in a dissociative fluid to release multiple reinforcing fibers; and Figure 11 The illustration shows fiber elements arranged in rolls for transport and / or storage. Detailed Implementation
[0043] Figure 1 A schematic exploded view of an example of a used wind turbine blade 10 is shown. For example, blade 10 could be a retired wind turbine blade that has reached the end of its service life. Blade 10 extends longitudinally between its root tip 12 and its tip 14. Figure 1 As shown, in some examples, the blade 10 may include a first half-shell 16a and a second half-shell 16b. The first and second half-shells 16a, 16b may be joined together to form a blade shell 18, which defines an aerodynamic profile and is configured to capture wind energy incident on the blade 10 in use.
[0044] The blade 10 also includes a longitudinally extending sparsity structure 20 configured to support the blade housing 18. For example, the sparsity structure may include shear webs 22 arranged between longitudinally extending sparsity caps 24 configured to withstand bending loads experienced by the blade 10 during operation. Figure 1 The example of a wind turbine blade 10 shown includes a single sparsity structure 20, but it should be understood that in some examples, the blade 10 may include multiple sparsity structures 20. Similarly, although Figure 1 The example shown includes a single spar cap 24 associated with each half-shell 16a, 16b, but in some other examples, the blade 10 may include multiple spar caps 24 associated with each half-shell 16a, 16b.
[0045] In some examples, the spar structure 20 may be at least partially incorporated (or integrated) into the blade housing 18. For example, each spar cap 24 may be embedded within a corresponding half-shell 16a, 16b, for instance, by bonding the spar cap 24 to multiple laminated layers during the manufacture of the half-shells 16a, 16b. In some other examples, the spar cap 24 may be incorporated to the inner surface of the corresponding half-shell 16a, 16b.
[0046] For further reference Figure 2 It shows an overview of an example of a spar cap 24 and a detailed view of the same spar cap. The spar structure 20 is at least partially formed of a fiber-reinforced composite material comprising a plurality of longitudinally extending reinforcing fibers 26, the reinforcing fibers 26 being oriented such that the fiber direction F of each reinforcing fiber 26 is substantially parallel to the longitudinal axis L of the blade 10. Figure 2The spar cap 24 shown (which in some examples may form part of the spar structure 20) is formed of a fiber-reinforced composite material including the reinforcing fibers 26 as described above. Figure 2 As shown, the spar structure 20 (spar cap 24 in this example) may include a multilayer fiber-reinforced composite pultrusion 28 arranged in a stacked configuration.
[0047] As will now be described in more detail with reference to the remaining figures, the fiber-reinforced material of the wind turbine blade 10 already in use can be prepared for new applications based on the examples described herein.
[0048] Figure 3 A fiber-reinforced composite 30 comprising a plurality of longitudinally extending reinforcing fibers 26 is shown. The method includes separating such a fiber-reinforced composite 30 from a used wind turbine blade 10. For example, as previously described, the sparsity structure 20 may be at least partially integrated into the blade shell 18. Therefore, separating the fiber-reinforced composite 30 from a used wind turbine blade 10 may involve separating the fiber-reinforced composite 30 from the blade shell 18. In some examples, such a process may involve cutting at least a portion of the sparsity structure 20 from the blade shell 18, such as at least a portion of the sparsity cap 24.
[0049] In some preferred embodiments, the fiber-reinforced composite 30 may comprise the entire spar cap 24, and therefore the method may involve separating the spar cap 24 from the used blade 10. Alternatively, the fiber-reinforced composite 30 may comprise a portion of the spar structure 20, such as a portion of the spar cap 24. Figure 3 As shown. Thus, in some examples, the fiber-reinforced composite 30 may include a multilayer fiber-reinforced composite pultrusion 28 attached together in a stack 32.
[0050] The preparation of fiber-reinforced materials in the method of the present invention includes breaking down the fiber-reinforced composite 30 into a plurality of fiber elements 34, as will now be referred to. Figures 4 to 10 As described. It should be understood, for reference only. Figures 4 to 10 Various fragmentation examples of the described fiber-reinforced composite 30 each produce a fiber element 34 comprising at least one longitudinally extending reinforcing fiber 26, and each fiber element 34 extends longitudinally in a direction substantially parallel to the fiber direction F of the corresponding at least one longitudinally extending reinforcing fiber 26.
[0051] like Figure 4 As shown, in some examples, fragmenting the fiber-reinforced composite 30 may involve cutting the fiber-reinforced composite 30 along a cutting axis C, which is substantially parallel to the fiber direction F of the reinforcing fibers 26 in the fiber-reinforced composite 30. For example, in some examples, such a cutting process may be performed using a circular saw 36 or a band saw.
[0052] Spallation structures typically have a main surface that follows the shape of the blade shell. The blade shell curves between the leading and trailing edges; therefore, even if the spallation structure only follows a portion of the shell between the leading and trailing edges, the main surface of the spallation structure curves slightly from the edge towards the leading edge to the edge towards the trailing edge. It has been found highly advantageous to cut or otherwise split the fiber-reinforced composite 30 in a plane parallel to the fiber direction and perpendicular to the orthogonal plane of the spallation structure or the pultruded member of the spallation structure, as this allows the spallation structure to be cut straight into nearly identical fiber elements 34, which are slices of the layers of the spallation structure. This allows the fiber elements to have very predictable and uniform properties. Examples of such fiber element 34 structures are shown in... Figure 9 It is shown in the upper right corner.
[0053] Alternatively, the fiber-reinforced composite 30 can be broken down into multiple fiber elements 34 during the splitting process, such as... Figures 5 to 7 As shown. In an example where the fiber-reinforced composite 30 comprises a multilayer fiber-reinforced composite pultrusion 28 attached together in a stack 32, the splitting process can be particularly advantageous, such as Figures 5 to 7 As shown. The splitting process preferably involves longitudinally splitting the fiber-reinforced composite 30 in a direction substantially parallel to the fiber direction F of the reinforcing fibers 26 in the composite 30. For example, a blade or splitting wedge 38 may be driven into and through the stack 32 to break the fiber-reinforced composite 30 into multiple fiber elements 34. An example of a splitting method will now be referred to. Figures 5 to 7 Describe it.
[0054] For example, such as Figure 5 As shown, the splitting process may include splitting at least one pultruded member 28 from an adjacent pultruded member 28 in the stack 32. Thus, the tip 40 of the blade or splitting wedge 38 may be aligned with the interface between adjacent pultruded members 28 in the stack 32, thereby splitting the pultruded member 28 from the adjacent (i.e., neighboring) pultruded member 28.
[0055] However, in some examples, the stack 32 may include a sandwich 42 between adjacent pultruded members 28 within the stack 32. Such a sandwich 42 may include adhesives and / or fiber reinforcement materials that may be difficult to split between adjacent pultruded members 28. Therefore, refer to... Figure 6 In some examples, the splitting process may include splitting one of the pultruded members 28 in the stack 32 into multiple fiber elements 34. For example, a blade or splitting wedge 38 may thus be aligned with the pultruded member 28 to split through it. For example, the matrix strength binding the reinforcing fibers 26 of the pultruded member 28 together may be significantly lower than the strength of the sandwich 42. Therefore, in some examples, splitting through the pultruded member 28 may be preferred.
[0056] In some other examples, such as Figure 7 As shown in the schematic plan view, the splitting process may involve simultaneously splitting multiple pultruded parts 28 in a stack 32. For example, the tip 40 of a blade or splitting wedge 38 may extend across multiple stacked pultruded parts 28, such that multiple pultruded parts 28 are split in the same splitting operation. In such an example, the fiber-reinforced composite 30 may be fragmented into multiple fiber elements 34, each fiber element comprising multiple reinforcing fibers 26 from multiple pultruded parts 28.
[0057] Such a splitting process can also be applied to examples in which the stack 32 includes an interlayer 42 of adhesive or resin (and optionally fiber reinforcement material) between adjacent pultrusions 28. Thus, in such an example, the fiber-reinforced composite 30 can be split into a plurality of fiber elements 34, each fiber element comprising reinforcing fibers 26 from a plurality of adjacent pultrusions 28 and a portion of a corresponding interlayer 42 between said adjacent pultrusions 28. A cross-sectional view of an example of the fiber elements 34 produced by such a splitting process is also shown. Figure 7 middle.
[0058] Now for reference Figure 8 A cross-sectional view showing another example of a fiber-reinforced composite 30, which includes a stack 32 of fiber-reinforced composite pultruded parts 28 attached together. The stack 32 may include a bonding region 44 at which adjacent pultruded parts 28 are attached to each other. For example, the pultruded parts 28 may be attached in the bonding region 44 by an epoxy resin or adhesive. Disintegrating the fiber-reinforced composite 30 may involve applying a dissociation fluid 46 to the bonding region 44 to facilitate the separation of adjacent pultruded parts 28 from each other.
[0059] It should be understood, for reference Figures 5 to 8 Each fragmentation method of the described fiber-reinforced composite 30 can produce a plurality of fiber elements 34, each fiber element comprising at least one reinforcing fiber 26 embedded in a polymer matrix material. For example, each fiber element 34 may comprise a portion of a fiber-reinforced composite pultrusion 28. Thus, in such an example, the fiber element 34 may be a composite component.
[0060] Figure 9 Cross-sectional views of several examples of composite fiber elements 48 are shown. Composite fiber elements 48 can be formed by combining fiber elements 34 after fragmentation from a fiber-reinforced composite 30. In examples involving attaching multiple fiber elements 34 together to form the composite fiber element 48, the fiber elements 34 are preferably arranged such that the fiber direction F of the reinforcing fibers 26 in each fiber element 34 is substantially parallel to the fiber direction F of the reinforcing fibers 26 in each other fiber element 34 of the composite fiber element 48. It should be understood that... Figure 9The fiber direction F of the reinforcing fiber 26 shown in the cross-sectional view extends into Figure 9 The paper.
[0061] Now for reference Figure 10 In some examples, the fiber-reinforced composite 30 may include reinforcing fibers 26 fixed in the polymer resin matrix 50 (the reinforcing fibers 26 are in... Figure 10 (Extending into the paper). In such an example, the reinforcing fiber 26 may be part of the corresponding pultruded part 28 as previously described, or in some examples, the reinforcing fiber 26 may simply be fixed in the polymer resin matrix 50 without necessarily being part of the pultruded part 28. Regardless of whether the reinforcing fiber 26 is part of the pultruded part 28, the method may include breaking down the fiber-reinforced composite 30 by applying a dissociation fluid 46 to the fiber-reinforced composite 30. For example, as Figure 10 As shown, the fiber-reinforced composite 30 may be at least partially immersed in a bath or container 52 of the dissociation fluid 46. Thus, in such an example, the dissociation fluid 46 may at least partially degrade the polymer resin matrix 50, thereby releasing one or more reinforcing fibers 26 from the polymer resin matrix 50. It should be understood that, in such an example, each released reinforcing fiber 26 may constitute a fiber element 34.
[0062] refer to Figure 11 As previously referenced Figures 4 to 10 After the fiber-reinforced composite 30 is broken into multiple fiber elements 34, the method may include winding the fiber elements 34. Storing and transporting the fiber elements 34 in rolls 54 is advantageous for maintaining the structural integrity of the reinforcing fibers 26 and reducing the overall space occupied by the fiber elements 34 for ease of handling and storage.
[0063] Although not shown in the accompanying drawings, in some examples, the method may additionally include reactivating the fiber elements 34 after they have been broken from the fiber-reinforced composite 30, for example by grinding the surface of the fiber elements 34. Other examples of reactivating the fiber elements 34 may involve adding a primer or slurry, and / or treating the surface of the fiber elements 34 with a dissociative fluid.
[0064] Such reactivation can be beneficial for improving the adhesion of the resin or adhesive to the fiber element 34 during subsequent manufacturing processes. Thus, in some examples, the method may include applying resin to the fiber element 34 and optionally curing the resin, but it should be understood that such method steps do not necessarily depend on the prior reactivation of the fiber element 34.
[0065] refer to Figures 4 to 11Example steps in a method for preparing fiber-reinforced material from a wind turbine blade 10 are described. Although not shown in the accompanying drawings, in some examples, the method for manufacturing a new wind turbine blade may include using one or more fiber elements 34 prepared according to examples of the previously described method. For example, to manufacture a new wind turbine blade, one or more fiber elements 34 may be arranged in a mold. Furthermore, one or more layers of blade shell material may be arranged in the mold, and resin may be supplied to the blade shell material and fiber elements 34 in the mold. The resin can then be cured at least partially, thereby bonding the one or more fiber elements 34 to the one or more layers of blade shell material.
[0066] Many modifications can be made to the above examples without departing from the scope of the invention as defined by the appended claims. Furthermore, it should be understood that the features described with respect to each of the above examples can be readily combined with features described with reference to other examples without departing from the scope of the invention as defined by the following claims.
Claims
1. A method for preparing fiber-reinforced materials from wind turbine blades, the method comprising: A wind turbine blade (10) is provided for use, the blade extending longitudinally between a root end (12) and a tip end (14), the blade including a blade shell (18) and a longitudinally extending sparsity structure (20) configured to support the shell (18), the sparsity structure (20) being at least partially formed of a fiber-reinforced composite material including a plurality of longitudinally extending reinforcing fibers (26) oriented such that the fiber direction F of each reinforcing fiber is substantially parallel to the longitudinal axis L of the blade; Fiber-reinforced composites (30) are separated from used wind turbine blades (10), the fiber-reinforced composites (30) comprising a plurality of longitudinally extending reinforcing fibers (26). The fiber-reinforced composite (30) is broken into a plurality of fiber elements (34), each fiber element (34) comprising at least one longitudinally extending reinforcing fiber (26), and each fiber element (34) extending longitudinally in a direction substantially parallel to the fiber direction F of the corresponding at least one longitudinally extending reinforcing fiber (26).
2. The method according to claim 1, wherein, The spar structure (20) is at least partially integrated into the blade housing (18), and wherein separating the fiber-reinforced composite (30) from the used wind turbine blade (10) includes separating the fiber-reinforced composite (30) from the blade housing (18).
3. The method according to claim 1 or claim 2, wherein, Separating the fiber-reinforced composite (30) from an existing wind turbine blade (10) includes cutting at least a portion of the spars structure (20) from the blade housing (18).
4. The method according to any one of the preceding claims, wherein, Breaking the fiber-reinforced composite (30) into multiple fiber elements (34) includes: longitudinally splitting the fiber-reinforced composite (30) in a direction substantially parallel to the fiber direction F of the reinforcing fibers (26) in the fiber-reinforced composite (30).
5. The method according to claim 4, wherein, The fiber-reinforced composite (30) includes a multilayer fiber-reinforced composite pultrusion (28) attached together in a stack (32), and wherein splitting the fiber-reinforced composite (30) includes splitting one of the pultrusions in the stack into a plurality of fiber elements (34).
6. The method according to claim 4 or claim 5, wherein, The fiber-reinforced composite (30) includes a multilayer fiber-reinforced composite pultrusion (28) attached together in a stack (32), and wherein splitting the fiber-reinforced composite (30) includes splitting a plurality of pultrusions in the stack such that the fiber-reinforced composite (30) is broken into a plurality of fiber elements (34), each fiber element including a plurality of reinforcing fibers (26) from the plurality of pultrusions.
7. The method according to claim 6, wherein, The stack (32) includes an interlayer (42) of adhesive or resin between adjacent pultrusions (28) and optional fiber reinforcement material, wherein splitting the fiber reinforcement composite (30) includes splitting the adjacent pultrusions and the corresponding interlayer (42) therebetween such that the fiber reinforcement composite (30) is broken into a plurality of fiber elements (34), each fiber element including a portion of reinforcing fibers (26) from a plurality of adjacent pultrusions and the corresponding interlayer (42) therebetween.
8. The method according to claim 4, wherein, The fiber-reinforced composite (30) includes a multilayer fiber-reinforced composite pultrusion (28) attached together in a stack (32), and wherein splitting the fiber-reinforced composite (30) includes splitting at least one pultrusion in the stack (32) from an adjacent pultrusion.
9. The method according to any one of claims 1 to 3, wherein, Breaking the fiber-reinforced composite (30) involves cutting the fiber-reinforced composite (30) along a cutting axis C, which is substantially parallel to the fiber direction F of the reinforcing fibers (26) in the fiber-reinforced composite (30).
10. The method according to any one of the preceding claims, wherein, Each fiber element (34) includes at least one reinforcing fiber (26) embedded in a polymer matrix material.
11. The method of claim 10, further comprising attaching a plurality of fiber elements (34) together to form a composite fiber element (48) comprising a plurality of reinforcing fibers (26), wherein, The fiber elements (34) are attached to each other such that the fiber direction F of one or more reinforcing fibers (26) in each fiber element (34) is substantially parallel to the fiber direction F of the reinforcing fibers (26) in each other fiber element (34) of the composite fiber element (48).
12. The method according to any one of claims 1 to 3, wherein, The blade housing (18) comprises a blade housing polymer resin matrix, and wherein separating the fiber-reinforced composite (30) from the used wind turbine blade (10) comprises applying a dissociation fluid (46) to the blade housing (18) to at least partially degrade the blade housing polymer resin matrix.
13. The method according to any one of claims 1 to 3, wherein, The fiber-reinforced composite (30) includes reinforcing fibers (26) fixed in a polymer resin matrix (50), and wherein breaking the fiber-reinforced composite (30) includes applying a dissociation fluid (46) to the fiber-reinforced composite (30) to at least partially degrade the polymer resin matrix, thereby releasing one or more reinforcing fibers (26) from the polymer resin matrix.
14. The method according to any one of claims 1 to 3, wherein, The fiber-reinforced composite (30) includes multilayer fiber-reinforced composite pultrusions (28) attached together in a stack (32), and wherein breaking the fiber-reinforced composite (30) includes applying a dissociation fluid (46) to a joint region (44) between adjacent pultrusions to separate the adjacent pultrusions from each other.
15. The method according to any one of the preceding claims further includes winding the fiber element (34) after the fiber element (34) is broken from the fiber-reinforced composite (30).
16. The method according to any one of the preceding claims further includes reactivating the fiber elements (34) after the fiber elements (34) are broken off from the fiber-reinforced composite (30).
17. The method according to any one of the preceding claims further includes applying resin to the fiber element (34) and optionally curing the resin.
18. A method for manufacturing a wind turbine blade, the method comprising: Fiber-reinforced materials are prepared according to any one of the preceding claims; One or more layers of blade shell material are arranged in the mold; One or more fiber elements (34) obtained by the method of any one of the preceding claims are arranged in the mold. Resin is supplied to the blade housing material and fiber element (34) in the mold; as well as The resin is at least partially cured to bond the one or more fiber elements (34) to the one or more blade shell materials.