A method for recovering glass fiber and carbon powder from waste wind turbine blades

Abstract

The present application relates to a method for recovering glass fiber and carbon powder from waste wind turbine blades, the method comprising the following steps: (1) crushing the waste wind turbine blades after removing the metal components into particles; (2) placing the waste wind turbine blade particles in an organic solvent containing a porogen at room temperature, fully soaking, filtering, and draining; the porogen is any one of polyethylene glycol, 1-vinyl-3-octadecyl imidazole bromide, and carboxymethyl cellulose; (3) subjecting the particles after draining in step (2) to a pyrolysis reaction under an inert atmosphere, the pyrolysis temperature is 300° C. to 350° C., the pyrolysis time is 1h to 2h, and a mixture of cracked carbon and glass fiber is generated; (4) the mixture of cracked carbon and glass fiber is ball-milled to obtain carbon powder and chopped glass fiber. The recovery method of the present invention has the advantages of low energy consumption, high recovery product quality, and high resource reuse value.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste resource utilization, and in particular, the present invention relates to a method for recovering glass fiber and carbon powder from waste wind turbine blades. Background Art

[0002] In recent years, with the green transformation of my country's energy, wind power generation has achieved unprecedented development. Blades are the core components of wind turbines. Their materials are mainly glass fiber reinforced epoxy resin composite materials, which are difficult to degrade and become "white garbage" after retirement, which not only pollutes the environment but also causes waste of resources. As the first batch of wind turbines put into operation reach the end of their service life, a large number of retired blades are in urgent need of disposal. Crushing the blades and using them as fillers to enhance and toughen building materials is an important way to realize the resource utilization of retired blades. However, due to the high resin content in the blade powder (about 45% by mass), the amount of building materials added is small (mass percentage <10%), otherwise it will affect the bulk performance of the building materials. Therefore, it is difficult to digest a large number of wind turbine blades that have reached the end of their service life by crushing them as building material fillers. How to realize the resource utilization of waste wind turbine blades is still a research focus in this field. Summary of the invention

[0003] The purpose of the present invention is to solve the technical problems in the related art to a certain extent. To this end, an embodiment of the present invention provides a method for recovering glass fiber and carbon powder from waste wind turbine blades.

[0004] A method for recovering glass fiber and carbon powder from waste wind turbine blades according to an embodiment of the present invention comprises the following steps:

[0005] (1) crushing the waste wind turbine blades after removing the metal components into particles;

[0006] (2) placing the waste wind turbine blade particles in an organic solvent containing a porogen at room temperature, fully soaking them, filtering them, and draining them; the porogen is any one of polyethylene glycol, 1-vinyl-3-octadecyl imidazolium bromide (ionic liquid), and carboxymethyl cellulose;

[0007] (3) subjecting the granules after draining in step (2) to a pyrolysis reaction under an inert atmosphere at a pyrolysis temperature of 300° C. to 350° C. for a pyrolysis time of 1 h to 2 h to generate a mixture of cracked carbon and glass fiber;

[0008] (4) The mixture of cracked carbon and glass fiber is ball-milled to obtain carbon powder and chopped glass fiber.

[0009] The method for recovering glass fiber and carbon powder from waste wind turbine blades in the embodiment of the present invention adopts swelling at room temperature and low temperature pyrolysis (300°C to 350°C) process, and then recovers glass fiber and carbon powder through ball milling. The recovery method of the present invention has the advantages of low energy consumption, large amount of recovered products, high quality of recovered products, and great resource recycling value.

[0010] In some embodiments, the particle size of the waste wind turbine blade particles after crushing in step (1) is 5 mm to 12 mm, and more preferably 8 mm to 10 mm.

[0011] In some embodiments, the mass concentration of the porogen is 5% to 10%.

[0012] In some embodiments, the organic solvent is one of ethanol, chloroform, and acetone.

[0013] In some embodiments, the soaking time of step (2) is 8 hours to 10 hours.

[0014] In some embodiments, the inert atmosphere in step (3) is a nitrogen, argon or helium atmosphere, with a total flow rate of 15 to 20 L / min. Preferably, the inert atmosphere is a nitrogen atmosphere.

[0015] In some embodiments, the ball milling process has a rotation speed of 180 r / min to 250 r / min and a time of 2 h to 3 h.

[0016] In some embodiments, the length of the chopped glass fibers is 4 mm to 8 mm, and the particle size of the carbon powder is 10 μm to 20 μm.

[0017] Compared with the related art, the present invention has the following beneficial effects:

[0018] (1) The traditional pulverization method can only obtain a mixed powder of resin and fiber, which is used as a building material additive in a small range. The recycling method of waste wind turbine blades of the present invention can obtain relatively pure (resin cracking) carbon powder and short glass fibers, which can then be widely used as raw materials for carbon materials and glass materials. That is, the present invention can make retired wind turbine blades more widely used as resources.

[0019] (2) The recycling method of the present invention utilizes an organic solvent that is chemically inert to epoxy resin and glass fiber to swell the crushed blade particles, thereby reducing the interaction between the epoxy resin and the glass fiber and facilitating low-temperature pyrolysis. During the swelling process, the porogen enters the swollen blade particles, which can effectively avoid the formation of a dense carbon layer during the blade pyrolysis process, increase the permeability of oxygen generated during the pyrolysis process, and facilitate obtaining relatively pure glass fiber and resin cracking carbon powder.

[0020] (3) The swelling process of the recycling method of the present invention is carried out at room temperature, and low-temperature pyrolysis (300°C to 350°C) is achieved. Compared with the traditional pyrolysis method (reacting at a temperature of >850°C to recover glass fiber, etc.), the recycling method of the present invention has the advantages of low energy consumption, more recovered products, high quality of recovered products, and great resource recycling value. DETAILED DESCRIPTION

[0021] Embodiments of the present invention are described in detail below. The embodiments described below are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0022] Unless otherwise specified, the raw materials and equipment in the embodiments of the present invention can be obtained through commercial channels.

[0023] A method for recovering glass fiber and carbon powder from waste wind turbine blades according to an embodiment of the present invention comprises the following steps:

[0024] (1) crushing the waste wind turbine blades after removing the metal components into particles;

[0025] (2) placing the waste wind turbine blade particles in an organic solvent containing a porogen at room temperature, fully soaking them, filtering them, and draining them; the porogen is any one of polyethylene glycol, 1-vinyl-3-octadecyl imidazolium bromide (ionic liquid), and carboxymethyl cellulose;

[0026] (3) subjecting the granules after draining in step (2) to a pyrolysis reaction under an inert atmosphere at a pyrolysis temperature of 300° C. to 350° C. for a pyrolysis time of 1 h to 2 h to generate a mixture of cracked carbon and glass fiber;

[0027] (4) The mixture of cracked carbon and glass fiber is ball-milled to obtain carbon powder and chopped glass fiber.

[0028] An embodiment of the present invention provides a method for recovering glass fiber and carbon powder from waste wind turbine blades. The method adopts swelling at room temperature and low-temperature pyrolysis (300°C to 350°C) and then ball milling to recover glass fiber and carbon powder. The recovery method of the present invention has the advantages of low energy consumption, large amount of recovered products, high quality of recovered products, and great value of resource recycling.

[0029] Non-limiting examples include: the pyrolysis temperature of step (3) can be: 300°C, 310°C, 315°C, 320°C, 330°C, 345°C, 350°C, etc., and the pyrolysis time is 1h, 1.2h, 1.5h, 1.6h, 1.7h, 1.8h, 2h, etc.

[0030] In some embodiments, the particle size of the waste wind turbine blade particles after crushing in step (1) is 5mm to 12mm. More preferably, it is 8mm to 10mm. The larger the crushed particles, the more difficult it is to swell, and the porogen cannot penetrate sufficiently into the particles, which will affect the pyrolysis effect. However, the smaller the crushed particles, the better the pyrolysis effect, but the higher the crushing energy consumption and the higher the cost. Preferably, the embodiment of the present invention controls the particle size of the wind turbine blade particles to be 8mm to 10mm. It can then swell better in organic solvents, thereby ensuring sufficient penetration of small molecules of the porogen, improving the pyrolysis effect, and controlling the crushing energy consumption.

[0031] For example, the particle size of the waste wind turbine blade particles after crushing in step (1) can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 10 mm, etc.

[0032] In some embodiments, the mass concentration of the porogen is 5% to 10%. In the embodiments of the present invention, the mass concentration of the porogen is controlled within the range of 5 to 10wt%, so that the porogen fully penetrates the waste wind turbine blade particles, thereby effectively preventing pyrolysis from forming a dense carbon layer. Non-limiting examples include: the mass concentration of the porogen can be 5%, 6%, 6.5%, 8%, 8.5%, 9%, 10%, etc.

[0033] In some embodiments, the organic solvent is one of ethanol, chloroform, and acetone.

[0034] In some embodiments, the soaking time of step (2) is 8 hours to 10 hours. For example, the soaking time of step (2) can be 8 hours, 8.2 hours, 8.5 hours, 9 hours, 9.2 hours, 9.5 hours, 10 hours, etc.

[0035] In some embodiments, the inert atmosphere in step (3) is a nitrogen, argon or helium atmosphere, and the total flow rate is 15 to 20 L / min. Preferably, the inert atmosphere is a nitrogen atmosphere. Non-limiting examples include: the total flow rate of the inert gas can be 15 L / min, 16 L / min, 16.5 L / min, 17 L / min, 17.5 L / min, 19 L / min, 20 L / min, etc.

[0036] In some embodiments, the ball milling speed is 180 r / min to 250 r / min, and the time is 2 h to 3 h. Non-limiting examples include: the ball milling speed can be 180 r / min, 190 r / min, 200 r / min, 210 r / min, 220 r / min, 230 r / min, 250 r / min, etc. The ball milling time can be 2 h, 2.1 h, 2.2 h, 2.3 h, 2.5 h, 2.8 h, 3 h, etc.

[0037] In some embodiments, the length of the chopped glass fibers is 4 mm to 8 mm, and the particle size of the carbon powder is 10 μm to 20 μm.

[0038] Example 1

[0039] A method for recovering glass fiber and carbon powder from waste wind turbine blades comprises the following steps:

[0040] (1) After removing the metal components, the waste wind turbine blades are crushed into particles with a particle size of about 10 mm;

[0041] (2) Take 100 g of waste wind turbine blade particles and soak them in 500 g of ethanol containing polyethylene glycol (containing 25 g of polyethylene glycol) at room temperature for 8 hours, then filter and drain.

[0042] (3) The drained particles were subjected to pyrolysis reaction under a nitrogen atmosphere (total flow rate of 20 L / min) at a pyrolysis temperature of 320° C. for 1.5 h to generate a mixture of pyrolyzed carbon and glass fiber;

[0043] (4) The mixture of cracked carbon and glass fiber was ball-milled in a planetary ball mill (model QM-3SP2) at a speed of 190 r / min for 2.5 h to obtain 30 g of carbon powder (10 μm-20 μm) and 53 g of chopped glass fiber (4 mm-8 mm).

[0044] In this embodiment, a Mettler Toledo thermogravimetric analyzer is used to test the resin content (glass fiber purity) in the recovered glass fiber. The lower the content, the more complete the degradation of the resin in the blade is, and the higher the purity of the recovered fiber is.

[0045] The glass fiber recovery rate was calculated based on the ratio of the mass of the recovered glass fiber to the actual amount of glass fiber used in the blade.

[0046] The carbon powder recovery rate is calculated according to the ratio of the mass of the recovered carbon powder to the theoretical cracking carbon amount of the matrix resin in the blade.

[0047] It is calculated that the recovery rate of carbon powder in Example 1 is 75%; the purity of glass fiber is 94.5%, and the recovery rate is 98%.

[0048] Example 2

[0049] A method for recovering glass fiber and carbon powder from waste wind turbine blades comprises the following steps:

[0050] (1) After removing the metal components, the waste wind turbine blades are crushed into particles with a particle size of about 9 mm;

[0051] (2) Take 100 g of waste wind turbine blade particles and soak them in 500 g of acetone containing 1-vinyl-3-octadecyl imidazolium bromide (containing 45 g of 1-vinyl-3-octadecyl imidazolium bromide) at room temperature for 8 hours, filter and drain.

[0052] (3) The drained particles were subjected to pyrolysis reaction under a nitrogen atmosphere (total flow rate of 20 L / min) at a pyrolysis temperature of 312° C. and a pyrolysis time of 1.7 h to generate a mixture of pyrolyzed carbon and glass fiber;

[0053] (4) The mixture of cracked carbon and glass fiber was ball-milled in a planetary ball mill (model QM-3SP2) at a rotation speed of 190 r / min for 2.5 h to obtain carbon powder (10 μm-20 μm) and short-cut glass fiber (4 mm-8 mm).

[0054] According to the calculation method of the carbon powder recovery rate and the purity / recovery rate of the glass fiber in Example 1, it is calculated that the carbon powder recovery rate in Example 2 is 75.8%; the purity of the glass fiber is 94.1%, and the recovery rate is 97.2%.

[0055] Example 3

[0056] A method for recovering glass fiber and carbon powder from waste wind turbine blades comprises the following steps:

[0057] (1) After removing the metal components, the waste wind turbine blades are crushed into particles with a particle size of about 8 mm;

[0058] (2) Take 100 g of waste wind turbine blade particles and soak them in 500 g of chloroform containing carboxymethyl cellulose (containing 30 g of carboxymethyl cellulose) at room temperature for 8 hours, then filter and drain.

[0059] (3) The drained particles were subjected to pyrolysis reaction under a nitrogen atmosphere (total flow rate of 20 L / min) at a pyrolysis temperature of 347° C. for 1.2 h to generate a mixture of cracked carbon and glass fiber;

[0060] (4) The mixture of cracked carbon and glass fiber was ball-milled in a planetary ball mill (model QM-3SP2) at a rotation speed of 190 r / min for 2.5 h to obtain carbon powder (10 μm to 20 μm) and short glass fiber (4 mm to 8 mm).

[0061] According to the calculation method of the carbon powder recovery rate and the purity / recovery rate of the glass fiber in Example 1, it is calculated that the carbon powder recovery rate in Example 3 is 70.2%; the purity of the glass fiber is 96.2%, and the recovery rate is 98.1%.

[0062] Example 4

[0063] A method for recovering glass fiber and carbon powder from waste wind turbine blades comprises the following steps:

[0064] (1) After removing the metal components, the waste wind turbine blades are crushed into particles with a particle size of about 9.5 mm;

[0065] (2) Take 100 g of waste wind turbine blade particles and soak them in 500 g of chloroform containing polyethylene glycol (containing 35.5 g of carboxymethyl cellulose) at room temperature for 8 hours, then filter and drain.

[0066] (3) The drained particles were subjected to pyrolysis reaction under a nitrogen atmosphere (total flow rate of 20 L / min) at a pyrolysis temperature of 308°C and a pyrolysis time of 1.9 h to generate a mixture of pyrolyzed carbon and glass fiber;

[0067] (4) The mixture of cracked carbon and glass fiber was ball-milled in a planetary ball mill (model QM-3SP2) at a rotation speed of 190 r / min for 2.5 h to obtain carbon powder (10 μm-20 μm) and short-cut glass fiber (4 mm-8 mm).

[0068] According to the calculation method of the carbon powder recovery rate and the purity / recovery rate of the glass fiber in Example 1, it is calculated that the carbon powder recovery rate in Example 4 is 76.2%; the purity of the glass fiber is 93.9%, and the recovery rate is 97.2%.

[0069] Example 5

[0070] A method for recovering glass fiber and carbon powder from waste wind turbine blades comprises the following steps:

[0071] (1) After removing the metal components, the waste wind turbine blades are crushed into particles with a particle size of about 5.5 mm;

[0072] (2) Take 100 g of waste wind turbine blade particles and soak them in 500 g of chloroform containing polyethylene glycol (containing 49 g of carboxymethyl cellulose) at room temperature for 8 hours, then filter and drain.

[0073] (3) The drained particles were subjected to pyrolysis reaction under a nitrogen atmosphere (total flow rate of 20 L / min) at a pyrolysis temperature of 336° C. and a pyrolysis time of 1.4 h to generate a mixture of pyrolyzed carbon and glass fiber;

[0074] (4) The mixture of cracked carbon and glass fiber was ball-milled in a planetary ball mill (model QM-3SP2) at a rotation speed of 190 r / min for 2.5 h to obtain carbon powder (10 μm to 20 μm) and short glass fiber (4 mm to 8 mm).

[0075] According to the calculation method of the carbon powder recovery rate and the purity / recovery rate of the glass fiber in Example 1, it is calculated that the carbon powder recovery rate in this Example 5 is 73.1%; the purity of the glass fiber is 95.2%, and the recovery rate is 98.6%.

[0076] Example 6

[0077] A method for recovering glass fiber and carbon powder from waste wind turbine blades comprises the following steps:

[0078] (1) After removing the metal components, the waste wind turbine blades are crushed into particles with a particle size of about 8.3 mm;

[0079] (2) Take 100 g of waste wind turbine blade particles and soak them in 500 g of ethanol containing 1-vinyl-3-octadecyl imidazolium bromide (including 25 g of 1-vinyl-3-octadecyl imidazolium bromide) at room temperature for 8 hours, filter and drain.

[0080] (3) The drained particles were subjected to pyrolysis reaction under a nitrogen atmosphere (total flow rate of 20 L / min) at a pyrolysis temperature of 305°C and a pyrolysis time of 2 h to generate a mixture of pyrolyzed carbon and glass fiber;

[0081] (4) The mixture of cracked carbon and glass fiber was ball-milled in a planetary ball mill (model QM-3SP2) at a rotation speed of 190 r / min for 2.5 h to obtain carbon powder (10 μm-20 μm) and short-cut glass fiber (4 mm-8 mm).

[0082] According to the calculation method of the carbon powder recovery rate and the purity / recovery rate of the glass fiber in Example 1, it is calculated that the carbon powder recovery rate in Example 6 is 76.8%; the purity of the glass fiber is 93.7%, and the recovery rate is 97.6%.

[0083] Example 7

[0084] A method for recovering glass fiber and carbon powder from waste wind turbine blades comprises the following steps:

[0085] (1) After removing the metal components, the waste wind turbine blades are crushed into particles with a particle size of about 8.3 mm;

[0086] (2) 100 g of waste wind turbine blade particles were placed in 500 g of ethanol containing 1-vinyl-3-octadecyl imidazolium bromide (containing 36.5 g of 1-vinyl-3-octadecyl imidazolium bromide) at room temperature and soaked for 8 hours, then filtered and drained.

[0087] (3) The drained particles were subjected to pyrolysis reaction under a nitrogen atmosphere (total flow rate of 20 L / min) at a pyrolysis temperature of 334° C. for 1.5 h to generate a mixture of pyrolyzed carbon and glass fiber;

[0088] (4) The mixture of cracked carbon and glass fiber was ball-milled in a planetary ball mill (model QM-3SP2) at a rotation speed of 190 r / min for 2.5 h to obtain carbon powder (10 μm to 20 μm) and short glass fiber (4 mm to 8 mm).

[0089] According to the calculation method of the carbon powder recovery rate and the purity / recovery rate of the glass fiber in Example 1, it is calculated that the carbon powder recovery rate in this Example 7 is 73.5%; the purity of the glass fiber is 95.4%, and the recovery rate is 98.4%.

[0090] Example 8

[0091] A method for recovering glass fiber and carbon powder from waste wind turbine blades comprises the following steps:

[0092] (1) After removing the metal components, the waste wind turbine blades are crushed into particles with a particle size of about 8.7 mm;

[0093] (2) Take 100 g of waste wind turbine blade particles and soak them in 500 g of chloroform containing carboxymethyl cellulose (containing 42.5 g of carboxymethyl cellulose) at room temperature for 8 hours, then filter and drain.

[0094] (3) The drained particles were subjected to pyrolysis reaction under a nitrogen atmosphere (total flow rate of 20 L / min) at a pyrolysis temperature of 321° C. and a pyrolysis time of 1.6 h to generate a mixture of pyrolyzed carbon and glass fiber;

[0095] (4) The mixture of cracked carbon and glass fiber was ball-milled in a planetary ball mill (model QM-3SP2) at a rotation speed of 190 r / min for 2.5 h to obtain carbon powder (10 μm to 20 μm) and short glass fiber (4 mm to 8 mm).

[0096] According to the calculation method of the carbon powder recovery rate and the purity / recovery rate of the glass fiber in Example 1, it is calculated that the carbon powder recovery rate in this Example 8 is 74.9%; the purity of the glass fiber is 94.5%, and the recovery rate is 97.9%.

[0097] The main reaction conditions and recovery effects of Examples 1 to 8 of the present invention are shown in Table 1.

[0098] Table 1 Relevant reaction conditions and recovery effects of Examples 1 to 8

[0099]

[0100] It can be seen from Table 1 that the recycling method of the present invention can effectively recycle carbon powder and glass fiber, and the recovery rate of carbon powder is above 70%, the purity of glass fiber is above 93%, the recovery rate is above 97%, the recycled products are large and the quality of the recycled products is high, which provides space for further resource utilization of carbon powder and glass fiber.

[0101] In addition, the recovery method of the present invention has a swelling process carried out at room temperature and a pyrolysis process carried out at a low temperature of 300° C. to 350° C., with low overall energy consumption and a large application space.

[0102] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0103] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for recovering glass fiber and carbon powder from waste wind turbine blades, characterized in that: The steps include: (1) crushing the waste wind turbine blades after removing the metal components into particles; (2) placing the waste wind turbine blade particles in an organic solvent containing a porogen at room temperature, fully soaking them, filtering them, and draining them; the porogen is any one of polyethylene glycol, 1-vinyl-3-octadecyl imidazole bromide, and carboxymethyl cellulose; (3) subjecting the granules after draining in step (2) to a pyrolysis reaction under an inert atmosphere at a pyrolysis temperature of 300° C. to 350° C. for a pyrolysis time of 1 h to 2 h to generate a mixture of cracked carbon and glass fiber; (4) The mixture of cracked carbon and glass fiber is ball-milled to obtain carbon powder and chopped glass fiber.

2. A method for recovering glass fiber and carbon powder from waste wind turbine blades according to claim 1, characterized in that: The particle size of the waste wind turbine blade particles after crushing in step (1) is 5 mm to 12 mm.

3. A method for recovering glass fiber and carbon powder from waste wind turbine blades according to claim 2, characterized in that: The particle size of the waste wind turbine blade particles after crushing in step (1) is 8 mm to 10 mm.

4. The method for recovering glass fiber and carbon powder from waste wind turbine blades according to claim 1, characterized in that: The mass concentration of the porogen is 5% to 10%.

5. The method for recovering glass fiber and carbon powder from waste wind turbine blades according to claim 4, characterized in that: The organic solvent is one of ethanol, chloroform and acetone.

6. A method for recovering glass fiber and carbon powder from waste wind turbine blades according to claim 5, characterized in that: The soaking time of step (2) is 8h to 10h.

7. The method for recovering glass fiber and carbon powder from waste wind turbine blades according to claim 1, characterized in that: The inert atmosphere in step (3) is nitrogen, argon or helium atmosphere, with a total flow rate of 15 to 20 L / min.

8. The method for recovering glass fiber and carbon powder from waste wind turbine blades according to claim 1, characterized in that: The speed during ball milling is 180r / min~250r / min, and the time is 2h~3h.

9. The method for recovering glass fiber and carbon powder from waste wind turbine blades according to claim 1, characterized in that: The length of the chopped glass fibers is 4 mm to 8 mm, and the particle size of the carbon powder is 10 μm to 20 μm.

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