Method for recovering glass fibers from retired fan blades

Abstract

The invention provides a method for recovering glass fibers from retired fan blades, and belongs to the technical field of resource recovery. The method for recovering the glass fibers from the retired fan blade comprises the following steps: cutting the retired fan blade to obtain a blade block; the blade block is subjected to a pyrolytic reaction, and a pyrolysis product is obtained; the temperature of the pyrolytic reaction ranges from 400 DEG C to 550 DEG C, and the time of the pyrolytic reaction ranges from 180 min to 300 min; carrying out oxidation reaction on the pyrolysis product in an air atmosphere to obtain glass fibers; the temperature of the oxidation reaction ranges from 450 DEG C to 550 DEG C, and the time of the oxidation reaction ranges from 50 min to 70 min. The retired fan blade is cut, so that the epoxy resin can be completely decomposed; by limiting the temperature and time of the pyrolytic reaction and the temperature and time of the oxidation reaction, the damage to the performance of the glass fiber can be reduced, so that the mechanical property is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of resource recovery, and in particular relates to a method for recovering glass fibers from retired wind turbine blades. Background Art

[0002] The fan blade is one of the core components of a wind turbine. It has excellent properties such as low weight, high strength, corrosion resistance and fatigue resistance. Its mass can account for up to 90% of the entire fan blade. At present, fan blades are mainly made of thermosetting resin-based composite materials reinforced with glass fibers or mixtures. Retired fan blades are mainly recycled by pyrolysis. The pyrolysis method utilizes the decomposition process in a high-temperature, oxygen-free environment to effectively separate the resin and fiber components and obtain high-quality regenerated fibers. However, there are still some problems with the pyrolysis method. Glass fibers are easily affected by high temperatures during the pyrolysis process, resulting in a decrease in their mechanical properties or damage to their microstructure, which seriously affects the quality of the recycled fibers. Therefore, how to improve the mechanical properties of glass fibers has become a technical problem that needs to be solved urgently by technicians in this field. Summary of the invention

[0003] The object of the present invention is to provide a method for recovering glass fibers from retired wind turbine blades. The glass fibers recovered by the method provided by the present invention have excellent mechanical properties.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for recovering glass fibers from retired wind turbine blades, comprising the following steps:

[0006] (1) Cutting retired wind turbine blades to obtain blade blocks;

[0007] (2) subjecting the blade block obtained in step (1) to a pyrolysis reaction to obtain a pyrolysis product; the pyrolysis reaction temperature is 400 to 550° C., and the pyrolysis reaction time is 180 to 300 min;

[0008] (3) subjecting the pyrolysis product obtained in step (2) to an oxidation reaction in an air atmosphere to obtain glass fiber; the oxidation reaction temperature is 450 to 550° C., and the oxidation reaction time is 50 to 70 minutes.

[0009] Preferably, the step (1) further includes removing metal components before cutting the retired wind turbine blades.

[0010] Preferably, the size of the blade block in step (1) is (20-30)×(20-30) mm.

[0011] Preferably, the temperature of the pyrolysis reaction in step (2) is 450-550° C., and the time of the pyrolysis reaction is 180-240 min.

[0012] Preferably, the temperature of the pyrolysis reaction in step (2) is 480-500° C., and the time of the pyrolysis reaction is 180-210 min.

[0013] Preferably, the pyrolysis reaction in step (2) is carried out in an inert atmosphere, and the inert atmosphere includes a nitrogen atmosphere.

[0014] Preferably, the flow rate of the nitrogen is 10 to 30 mL / min.

[0015] Preferably, the temperature of the oxidation reaction in step (2) is 500-550° C., and the time of the oxidation reaction is 55-60 min.

[0016] Preferably, the flow rate of air in step (3) is 90 to 110 mL / min.

[0017] Preferably, the flow rate of air in step (3) is 100 mL / min.

[0018] The present invention provides a method for recovering glass fiber from retired fan blades, comprising the following steps: cutting retired fan blades to obtain blade blocks; subjecting the blade blocks to pyrolysis reaction to obtain pyrolysis products; the temperature of the pyrolysis reaction is 400-550°C, and the time of the pyrolysis reaction is 180-300 minutes; subjecting the pyrolysis products to oxidation reaction in an air atmosphere to obtain glass fiber; the temperature of the oxidation reaction is 450-550°C, and the time of the oxidation reaction is 50-70 minutes. The present invention cuts retired fan blades, which can avoid the problem of local overheating or uneven heating caused by pyrolysis of large blocks of materials, ensures that the blade blocks can be pyrolyzed uniformly, so that the epoxy resin can be completely decomposed. Afterwards, during the pyrolysis reaction and oxidation reaction, by limiting the temperature and time of the pyrolysis reaction and the temperature and time of the oxidation reaction, the damage to the performance of the glass fiber can be reduced on the basis of decomposing the epoxy resin, and the purity and quality of the recovered glass fiber can be improved on the basis of removing organic residues and carbonaceous impurities in the pyrolysis products, thereby improving the mechanical properties of the glass fiber. Experimental results show that the tensile strength retention rate of the glass fiber prepared by the method provided by the present invention is above 60%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the SEM image of the glass fiber prepared in Example 1. DETAILED DESCRIPTION

[0020] The present invention provides a method for recovering glass fibers from retired wind turbine blades, comprising the following steps:

[0021] (1) Cutting retired wind turbine blades to obtain blade blocks;

[0022] (2) subjecting the blade block obtained in step (1) to a pyrolysis reaction to obtain a pyrolysis product; the pyrolysis reaction temperature is 400 to 550° C., and the pyrolysis reaction time is 180 to 300 min;

[0023] (3) subjecting the pyrolysis product obtained in step (2) to an oxidation reaction in an air atmosphere to obtain glass fiber; the oxidation reaction temperature is 450 to 550° C., and the oxidation reaction time is 50 to 70 minutes.

[0024] The method provided by the present invention is applicable to retired wind turbine blades made of any material.

[0025] The present invention has no particular limitation on the source of retired wind turbine blades, and commercially available products known to those skilled in the art may be used.

[0026] The present invention cuts the retired fan blades to obtain blade blocks. The present invention cuts the retired fan blades to avoid the problem of local overheating or uneven heating caused by pyrolysis of large blocks of materials, ensuring that the blade blocks can be evenly pyrolyzed, thereby completely decomposing the epoxy resin.

[0027] In the present invention, the decommissioned wind turbine blades preferably include removing metal components before cutting. The present invention has no special limitation on the operation of removing the metal components, and operations well known to those skilled in the art can be used.

[0028] The present invention has no special limitation on the cutting operation, as long as the blade blocks of the required size are obtained.

[0029] In the present invention, the size of the blade block is preferably (20-30)×(20-30) mm, more preferably 25×25 mm. The present invention limits the size of the blade block to the above range to avoid the problem of local overheating or uneven heating caused by the pyrolysis of large blocks of material; ensure that each small block of material can be evenly contacted with the high-temperature medium to improve the efficiency of material decomposition; at the same time, heat can penetrate faster and decompose the epoxy resin, thereby shortening the pyrolysis time and improving the overall processing efficiency.

[0030] After obtaining the blade block, the present invention performs a pyrolysis reaction on the blade block to obtain a pyrolysis product.

[0031] In the present invention, the temperature of the pyrolysis reaction is 400-550°C; the time of the pyrolysis reaction is 180-300 minutes. The present invention can reduce the damage to the performance of the glass fiber on the basis of decomposing the epoxy resin by limiting the temperature and time of the pyrolysis reaction, thereby improving the mechanical properties of the glass fiber.

[0032] As an embodiment, the temperature of the pyrolysis reaction may be 450-550°C, or may be 500°C.

[0033] As an implementation mode, the pyrolysis reaction time may be 210 to 270 minutes, or may be 240 minutes.

[0034] In the present invention, the pyrolysis reaction is preferably carried out in an inert atmosphere; the inert atmosphere preferably includes a nitrogen atmosphere; the flow rate of the nitrogen is preferably 10 to 30 mL / min, more preferably 20 mL / min. The pyrolysis reaction in an inert atmosphere of the present invention can avoid excessive emission of harmful gases such as carbon dioxide.

[0035] In the present invention, the pyrolysis reaction is preferably carried out in a tube furnace. The present invention has no particular limitation on the type of the tube furnace, and any equipment well known to those skilled in the art can be used.

[0036] After the pyrolysis reaction is completed, the present invention preferably cools the product obtained by the pyrolysis reaction to obtain a pyrolysis product.

[0037] The present invention has no particular limitation on the cooling operation, and cooling to room temperature may be performed using an operation well known to those skilled in the art.

[0038] After obtaining the pyrolysis product, the present invention performs an oxidation reaction on the pyrolysis product in an air atmosphere to obtain glass fiber. The present invention uses an oxidation reaction to remove organic residues and carbonaceous impurities in the pyrolysis product, thereby improving the purity and quality of the recovered glass fiber.

[0039] In the present invention, the temperature of the oxidation reaction is 450-550°C; the time of the oxidation reaction is 50-70 minutes. By limiting the temperature and time of the oxidation reaction, the present invention can reduce the damage to the performance of the glass fiber on the basis of decomposing the epoxy resin, improve the purity and quality of the recycled glass fiber, and thus improve the mechanical properties of the glass fiber.

[0040] As an embodiment, the temperature of the oxidation reaction may be 500-550°C.

[0041] As an embodiment, the oxidation reaction time may be 55 to 60 minutes.

[0042] In the present invention, the flow rate of the air is preferably 90 to 110 mL / min, more preferably 100 mL / min.

[0043] In the present invention, the oxidation reaction is preferably carried out in a tube furnace. The present invention has no particular limitation on the type of the tube furnace, and any equipment well known to those skilled in the art can be used.

[0044] After the oxidation reaction is completed, the present invention preferably cools and takes out the product obtained by the oxidation reaction in sequence to obtain glass fiber.

[0045] The present invention has no particular limitation on the cooling and taking-out operations, and operations well known to those skilled in the art may be adopted.

[0046] The present invention cuts retired wind turbine blades, thereby avoiding the problem of local overheating or uneven heating caused by pyrolysis of large blocks of material, ensuring that the blade blocks can be evenly pyrolyzed, thereby completely decomposing the epoxy resin. Subsequently, during the pyrolysis reaction and the oxidation reaction, by limiting the temperature and time of the pyrolysis reaction and the temperature and time of the oxidation reaction, it is possible to reduce damage to the performance of the glass fiber on the basis of decomposing the epoxy resin, and to improve the purity and quality of the recycled glass fiber on the basis of removing organic residues and carbonaceous impurities in the pyrolysis products, thereby improving the mechanical properties of the glass fiber.

[0047] The present invention processes retired fan blades through tubular furnace pyrolysis technology, optimizes the operating parameters of the tubular furnace (temperature and time of pyrolysis reaction and temperature and time of oxidation reaction), obtains the best recovery effect, improves the stability of the pyrolysis process, and minimizes the damage to the glass fiber; the recovered glass fiber maintains high physical and chemical properties, especially strength and structural stability; the present invention reduces the negative impact of the oxidation reaction on the environment by adopting an inert atmosphere and optimizing the temperature control of the oxidation reaction, avoids excessive emission of harmful gases such as carbon dioxide, and meets the technical requirements of green environmental protection.

[0048] The method proposed in the present invention can effectively reduce, render harmless and recycle retired wind turbine blades, and can also efficiently recycle clean glass fibers with high recycling value. The process is simple and efficient, has the advantages of energy saving and environmental protection, and can reduce the environmental burden while increasing the economic value of recycled materials.

[0049] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] The materials in the examples were prepared according to existing methods or directly purchased from the market.

[0051] In the embodiment, the tensile strength retention rate of the glass fiber is used as the recycling effect evaluation index, and the calculation formula is shown in Formula I:

[0052]

[0053] In formula I, X is the tensile strength retention rate of the regenerated glass fiber, in %, σ is the tensile strength of the regenerated glass fiber, in MPa; σ0 is the tensile strength of the original glass fiber, in MPa.

[0054] Calculated by mass percentage, the retired wind turbine blades used in the embodiment are composed of: 30% epoxy resin, 60% glass fiber, and 10% sandwich material, adhesive and auxiliary materials.

[0055] Example 1

[0056] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0057] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0058] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 500° C. in a nitrogen atmosphere for pyrolysis reaction for 240 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0059] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 500° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0060] Figure 1 This is the SEM image of the glass fiber prepared in Example 1.

[0061] from Figure 1 It can be seen that the glass fibers exhibit a high surface smoothness and there is almost no attachment on the surface after oxidation, indicating that this is a thorough reaction and the organic matter has been completely removed.

[0062] Example 2

[0063] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0064] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0065] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 450° C. in a nitrogen atmosphere for pyrolysis reaction for 240 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0066] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 500° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0067] Example 3

[0068] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0069] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0070] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 400° C. in a nitrogen atmosphere for pyrolysis reaction for 240 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0071] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 500° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0072] Example 4

[0073] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0074] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0075] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 550° C. in a nitrogen atmosphere for pyrolysis reaction for 240 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0076] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 500° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0077] Example 5

[0078] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0079] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0080] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 500° C. in a nitrogen atmosphere for pyrolysis reaction for 180 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0081] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 500° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0082] Example 6

[0083] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0084] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0085] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 500° C. in a nitrogen atmosphere for pyrolysis reaction for 210 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0086] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 500° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0087] Example 7

[0088] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0089] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0090] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 500° C. in a nitrogen atmosphere for pyrolysis reaction for 270 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0091] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 500° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0092] Example 8

[0093] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0094] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0095] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 500° C. in a nitrogen atmosphere for pyrolysis reaction for 300 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0096] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 500° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0097] Example 9

[0098] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0099] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0100] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 500° C. in a nitrogen atmosphere for pyrolysis reaction for 180 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0101] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 450° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0102] Example 10

[0103] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0104] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0105] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 500° C. in a nitrogen atmosphere for pyrolysis reaction for 180 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0106] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 500° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0107] Embodiment 11

[0108] The method for recovering glass fiber from retired wind turbine blades is as follows:

[0109] (1) Remove the metal components on the retired wind turbine blades and then cut them mechanically to obtain blade blocks with a size of 25×25 mm;

[0110] (2) placing the blade block obtained in step (1) in a tubular furnace quartz tube at 500° C. in a nitrogen atmosphere for pyrolysis reaction for 180 min, and then cooling to room temperature to obtain a pyrolysis product; wherein the flow rate of the nitrogen is 20 mL / min;

[0111] (3) placing the pyrolysis product obtained in step (2) in a quartz tube of a tubular furnace at 550° C. in an air atmosphere for oxidation reaction for 60 minutes, then cooling to room temperature, and then taking out to obtain glass fiber; wherein the air flow rate is 100 mL / min.

[0112] The glass fibers prepared in Examples 1 to 11 were subjected to tensile tests according to ASTM C1557-0. The results are shown in Table 1, wherein the tensile strength of the original glass fibers was 1000 MPa.

[0113] Table 1 Process parameters of Examples 1 to 11 and performance data of glass fibers

[0114]

[0115] It can be seen from Table 1 that the glass fiber prepared by the method provided by the present invention has excellent mechanical properties, which proves that the method proposed by the present invention has excellent recycling effect.

[0116] It can be seen from the above embodiments that the glass fiber recovered by the method provided by the present invention has excellent mechanical properties, wherein the optimal recovery conditions are a pyrolysis temperature of 500°C, a pyrolysis time of 180 min, and an oxidation temperature of 500°C, and an oxidation time of 60 min.

[0117] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for recovering glass fibers from retired wind turbine blades, characterized in that: The following steps are involved: (1) Cutting retired wind turbine blades to obtain blade blocks; (2) subjecting the blade block obtained in step (1) to a pyrolysis reaction to obtain a pyrolysis product; the pyrolysis reaction temperature is 400 to 550° C., and the pyrolysis reaction time is 180 to 300 min; (3) subjecting the pyrolysis product obtained in step (2) to an oxidation reaction in an air atmosphere to obtain glass fiber; the oxidation reaction temperature is 450 to 550° C., and the oxidation reaction time is 50 to 70 minutes.

2. The method according to claim 1, characterized in that The step (1) also includes removing metal components before cutting the retired wind turbine blades.

3. The method according to claim 1, characterized in that The size of the blade block in step (1) is (20-30)×(20-30) mm.

4. The method according to claim 1, characterized in that: The temperature of the pyrolysis reaction in step (2) is 450-550° C., and the time of the pyrolysis reaction is 180-240 min.

5. The method according to claim 1 or 4, characterized in that: The temperature of the pyrolysis reaction in step (2) is 480-500° C., and the time of the pyrolysis reaction is 180-210 min.

6. The method according to claim 1, characterized in that The pyrolysis reaction in step (2) is carried out in an inert atmosphere, which includes a nitrogen atmosphere.

7. The method according to claim 6, characterized in that The flow rate of the nitrogen gas is 10-30 mL / min.

8. The method according to claim 1, characterized in that The temperature of the oxidation reaction in step (2) is 500-550° C., and the time of the oxidation reaction is 55-60 minutes.

9. The method according to claim 1, characterized in that: The flow rate of air in step (3) is 90 to 110 mL / min.

10. The method according to claim 1 or 9, characterized in that: The flow rate of air in step (3) is 100 mL / min.

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