Method for resourceful treatment of waste carbon fiber wind turbine blades

Abstract

The present application relates to a method for a resourceful treatment of waste carbon fiber wind turbine blades. The method comprises the following steps: (1) separating balsa wood from waste carbon fiber wind turbine blades, then pyrolyzing same, and modifying same with an alkali liquor, so as to obtain a pyrolyzed balsa wood catalyst; and (2) subjecting the waste carbon fiber wind turbine blades from which the balsa wood is separated and the pyrolyzed balsa wood catalyst obtained in step (1) to a microwave co-pyrolysis treatment, so as to obtain pyrolysis gas, pyrolytic oil and pyrolytic carbon. In the present application, by subjecting the tar generated during the process of microwave co-pyrolysis to in-situ catalytic cracking, the subsequent coking problem of a pyrolysis device is ameliorated; and compared with conventional pyrolysis conditions, the energy consumption of pyrolysis is reduced, and the content of pyrolytic oil is reduced, which are conducive to the rapid implementation of resource recycling during the subsequent treatment process of the waste carbon fiber wind turbine blades.

Description

A method for resource processing of waste carbon fiber fan blades Technical Field

[0001] The present application relates to the technical field of waste wind turbine blade processing, for example, a method for resource-based processing of waste carbon fiber wind turbine blades. Background Art

[0002] With the continuous development of the wind power industry, wind turbine blade types have gradually been replaced by lighter carbon fiber blades, rather than glass fiber blades. The service life of a wind turbine blade is approximately 20 years, and the number of retired wind turbine blades is increasing year by year. Therefore, the proper disposal of wind turbine blades has become a topic that urgently requires research and development. Industrialized carbon fiber wind blades are composite materials, consisting of a composite material of carbon fiber and resin, and a sandwich material bonded together with an adhesive. Currently, the core material of most carbon fiber wind blades on the market is lightweight balsa wood, while the resin composite material is primarily composed of epoxy resin. Therefore, when exploring methods for recycling retired wind turbine blades, the clean and quick removal of the balsa wood and resin composite material is crucial.

[0003] CN 116001144A discloses a method and system for recycling waste fan blades. The method comprises the following steps: (1) crushing and pulverizing the waste fan blades to obtain waste fan blade fragments; (2) subjecting the waste fan blade fragments to a pyrolysis reaction at an absolute pressure of ≤100 Pa to obtain pyrolysis gas and solid products, followed by condensing the pyrolysis gas to obtain pyrolysis oil; and (3) calcining the solid products. However, the pyrolysis energy consumption in this method is high, and condensing the pyrolysis gas to obtain pyrolysis oil may cause equipment coking.

[0004] Microwave pyrolysis is a relatively mature technology for the pyrolysis treatment of solid waste. Unlike conventional pyrolysis, microwave pyrolysis utilizes the energy of microwave radiation to heat materials and accelerate their decomposition. The treated material is directly exposed to the microwave radiation field, where the microwave energy is absorbed and converted into heat, rapidly heating the material and evenly decomposing and vaporizing it from within, ultimately producing pollution-free pyrolysis products. Furthermore, during operation, microwave pyrolysis can be connected to a high-temperature incinerator via a pipeline, allowing direct combustion of flue gas without producing pollutants such as dioxins. Furthermore, when treating composite materials such as resins during microwave pyrolysis, a condensation system can be added to collect large amounts of liquid and gaseous components. The pyrolysis residue, such as carbon fiber, retains its original high thermal and electrical conductivity. Therefore, microwave pyrolysis technology has gradually become a research topic in the fields of solid waste, energy, and health.

[0005] CN 114963183A discloses a microwave pyrolysis blade treatment system and method. The system comprises a pyrolysis furnace and an impurity removal tower. The pyrolysis furnace includes a pyrolysis furnace body, a microwave emission source mounted on the upper portion of the pyrolysis furnace body, a rotating base mounted on the lower portion, and a rotating platform mounted above the rotating base. The pyrolysis furnace body has a smoke outlet at the front end, which is connected to the inlet of a booster induced draft fan via a pipeline. The outlet of the booster induced draft fan is connected to the flue gas inlet of an absorption cooling tower. The absorption cooling tower is connected to a water tank and a fluid separator, respectively. The fluid separator is connected to an oil tank and a hydrochloric acid tank, respectively. However, this method uses microwaves to treat blades, producing a large amount of liquid tar. This, combined with dust from the pyrolysis process, can cause pipeline blockage and equipment damage.

[0006] In addition, a large amount of tar produced during the long pyrolysis process will also adhere to the inner surface of the furnace, affecting the temperature and heat energy transfer in the furnace. In order to achieve the same pyrolysis effect, the pyrolysis power and temperature need to be gradually increased, which limits the industrial microwave pyrolysis treatment technology.

[0007] Therefore, in view of the shortcomings of the relevant technologies, there is an urgent need to provide a method with low pyrolysis energy consumption, low tar production and the ability to completely recover pyrolytic carbon.

[0008] Summary of the Invention

[0009] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0010] The present application provides a method for resource-based treatment of waste carbon fiber fan blades, which solves the problems of uneven heating, large energy loss, and large tar production caused by the disposal of waste carbon fiber fan blades.

[0011] The present application provides a method for resource-recycling waste carbon fiber wind turbine blades, the method comprising the following steps:

[0012] (1) Balsa wood is separated from waste carbon fiber fan blades and then pyrolyzed and modified with alkaline solution to obtain a pyrolysis balsa wood catalyst;

[0013] (2) subjecting the waste carbon fiber fan blades after separation of balsa wood to microwave co-pyrolysis treatment with the pyrolysis balsa wood catalyst obtained in step (1) to obtain pyrolysis gas, pyrolysis oil and pyrolysis char.

[0014] The method for resource recovery of waste carbon fiber fan blades provided in the present application makes full use of waste carbon fiber fan blades as raw materials, which can reduce the cost of waste fan blades in the disposal process; at the same time, mixed carbon, as a microwave energy absorbing material, can change the dielectric constant in waste carbon fiber fan blades, fully improve the microwave heating rate and the uniformity of pyrolysis heating, and further reduce reaction energy consumption; the tar produced in the microwave co-pyrolysis process is used for in-situ catalytic cracking, which can fully convert the macromolecules in the organic resin pyrolysis process into small molecule combustible gas, and achieve the in-situ removal effect of the liquid product tar in the microwave co-pyrolysis reaction process, reducing the coking problem of subsequent pyrolysis equipment, and completely recovering the pyrolytic carbon while completely removing the organic components contained in the blades, which is conducive to the rapid recovery of resources in the subsequent disposal of waste carbon fiber fan blades, and expands the industrial application field method of microwave pyrolysis of waste carbon fiber.

[0015] In one embodiment, the mass of the balsa wood in step (1) is 20-100 g, for example, 20 g, 40 g, 60 g, 80 g or 100 g, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] In one embodiment, the pyrolysis temperature in step (1) is 250-500°C, for example, 250°C, 300°C, 350°C, 400°C or 500°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] In one embodiment, the pyrolysis time in step (1) is 0.8-1.2 h, for example, 0.8 h, 0.9 h, 1 h, 1.1 h or 1.2 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] The pyrolysis is carried out using a variable frequency microwave pyrolysis unit.

[0019] In one embodiment, after the pyrolysis in step (1) and before the alkali solution modification, the steps of grinding and screening are further included.

[0020] In one embodiment, the grinding and sieving are to grind the residue obtained after pyrolysis and pass it through a 50-200 mesh sieve to obtain mixed carbon. The 50-200 mesh sieve can be, for example, a 50 mesh sieve, an 80 mesh sieve, a 100 mesh sieve, a 140 mesh sieve or a 200 mesh sieve, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0021] In one embodiment, the alkali solution modification step in step (1) comprises: uniformly mixing the alkali solution with the mixed carbon, separating the solid and liquid after impregnation, and vacuum drying the obtained solid phase.

[0022] Modifying the mixed carbon with alkaline solution can change the surface functional groups of the mixed carbon, while improving the pore structure of the material, thereby increasing the active sites of the material.

[0023] In one embodiment, the mass ratio of the mixed carbon to the alkali solution is (1-5):(2-10), for example, it can be 1:2, 2:3, 3:5, 4:7 or 5:9, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] In one embodiment, the solute concentration of the alkali solution is 2-5 mol / L, for example, 2 mol / L, 2.5 mol / L, 3 mol / L, 4 mol / L or 5 mol / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] In one embodiment, the alkali solution includes sodium hydroxide solution and / or potassium hydroxide solution.

[0026] In one embodiment, the immersion time is 11-13 hours, for example, 11 hours, 11.5 hours, 12 hours, 12.5 hours or 13 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] In one embodiment, the vacuum drying temperature is 78-82°C, for example, 78°C, 79°C, 80°C, 81°C or 82°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] In one embodiment, the vacuum drying time is 5-7 hours, for example, 5 hours, 5.5 hours, 6 hours, 6.5 hours or 7 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] In one embodiment, the mass ratio of the waste carbon fiber fan blades after separation of balsa wood in step (2) to the pyrolysis balsa wood catalyst is (5-10):1, for example, it can be 5:1, 6:1, 8:1, 9:1 or 10:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] The mass ratio of the waste carbon fiber fan blades after separating the balsa wood to the pyrolysis balsa wood catalyst is limited to a reasonable range, which can promote the secondary cracking of oxygen-containing compounds and, on the other hand, promote the occurrence of the diene synthesis synergistic reaction. If the mass ratio is too high or too low, the polymerization and cross-linking reactions will be inhibited.

[0031] In one embodiment, the microwave power of the microwave co-pyrolysis treatment in step (2) is 580-620 W, for example, 580 W, 590 W, 600 W, 610 W or 620 W, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] In one embodiment, the temperature of the microwave co-pyrolysis treatment in step (2) is 400-600°C, for example, 400°C, 450°C, 500°C, 550°C or 600°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] The temperature of the microwave co-pyrolysis treatment is within a reasonable range, which can promote the conversion of large molecules into small molecular combustible gases, achieve the in-situ removal effect of the liquid product tar during the microwave co-pyrolysis reaction, and reduce the coking problem of subsequent pyrolysis equipment. If the temperature is too high or too low, it will be difficult to avoid the coking problem.

[0034] In one embodiment, the time of the microwave co-pyrolysis treatment in step (2) is 0.5-1 h, for example, 0.5 h, 0.6 h, 0.8 h, 0.9 h or 1 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] As an optional technical solution of the method described in this application, the method includes the following steps:

[0036] (1) Separating balsa wood from waste carbon fiber fan blades, the mass of balsa wood is 20-100 g, and then pyrolyzing at 250-500 ° C for 0.8-1.2 hours, grinding the obtained residue and passing it through a 50-200 mesh sieve to obtain a mixed carbon; uniformly mixing an alkali solution with a solute concentration of 2-5 mol / L and the mixed carbon, the mass ratio of the mixed carbon to the alkali solution being (1-5): (2-10), impregnating for 11-13 hours, and then separating the solid and liquid, and vacuum drying the obtained solid phase at 78-82 ° C for 5-7 hours to obtain a pyrolysis balsa wood catalyst;

[0037] (2) The waste carbon fiber fan blades after separation of balsa wood with a mass ratio of (5-10):1 are subjected to microwave co-pyrolysis treatment with the pyrolysis balsa wood catalyst obtained in step (1), with a microwave power of 580-620 W, a temperature of 400-600° C., and a time of 0.5-1 h to obtain pyrolysis gas, pyrolysis oil and pyrolysis carbon.

[0038] Compared with the related art, this application has the following beneficial effects:

[0039] The method for resource recovery of waste carbon fiber fan blades provided by the present application makes full use of waste carbon fiber fan blades as raw materials, which can reduce the cost of waste fan blades in the disposal process; at the same time, mixed carbon, as a microwave energy absorbing material, can change the dielectric constant in waste carbon fiber fan blades, fully improve the microwave heating rate and the uniformity of pyrolysis heating, and further reduce reaction energy consumption; the present application also utilizes the in-situ catalytic cracking of tar produced in the microwave co-pyrolysis process, which can fully convert the macromolecules in the organic resin pyrolysis process into small molecule combustible gas, and achieve the in-situ removal effect of liquid phase product tar in the microwave co-pyrolysis reaction process, reducing the coking problem of subsequent pyrolysis equipment, and completely recovering the pyrolytic carbon while completely removing the organic components contained in the blades. Compared with conventional pyrolysis conditions, the pyrolysis energy consumption is reduced by 30.6%, and the pyrolysis oil content is reduced by 62.6%, which is conducive to the rapid recovery of resources in the subsequent disposal of waste carbon fiber fan blades, and expands the industrial application field method of microwave pyrolysis of waste carbon fiber.

[0040] Still other aspects will become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0041] The technical solution of the present application is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations of the present application.

[0042] Example 1

[0043] This embodiment provides a method for resource recovery of waste carbon fiber wind turbine blades, the method comprising the following steps:

[0044] (1) Balsa wood was separated from waste carbon fiber fan blades, with a mass of 40 g of balsa wood, and then pyrolyzed at 300°C for 1 hour. The resulting residue was ground and passed through a 100-mesh sieve to obtain mixed carbon; a sodium hydroxide solution with a solute concentration of 3 mol / L and the mixed carbon were evenly mixed, with the mass ratio of the mixed carbon to the sodium hydroxide solution being 1:2. After immersion for 12 hours, solid-liquid separation was performed, and the resulting solid phase was vacuum dried at 80°C for 6 hours to obtain a pyrolysis balsa wood catalyst;

[0045] (2) The waste carbon fiber fan blades after separation of balsa wood with a mass ratio of 8:1 were subjected to microwave co-pyrolysis treatment with the pyrolysis balsa wood catalyst obtained in step (1) at a microwave power of 600 W, a temperature of 500° C., and a time of 0.8 h to obtain pyrolysis gas, pyrolysis oil, and pyrolysis char.

[0046] Example 2

[0047] This embodiment provides a method for resource recovery of waste carbon fiber wind turbine blades, the method comprising the following steps:

[0048] (1) Balsa wood was separated from waste carbon fiber fan blades, with a mass of 20 g of balsa wood, and then pyrolyzed at 250°C for 1.2 h. The resulting residue was ground and passed through a 50-mesh sieve to obtain mixed carbon; a sodium hydroxide solution with a solute concentration of 2 mol / L and the mixed carbon were evenly mixed, with the mass ratio of the mixed carbon to the sodium hydroxide solution being 3:5. After immersion for 11 h, solid-liquid separation was performed, and the resulting solid phase was vacuum dried at 78°C for 7 h to obtain a pyrolysis balsa wood catalyst;

[0049] (2) The waste carbon fiber fan blades after separation of balsa wood with a mass ratio of 8:1 were subjected to microwave co-pyrolysis treatment with the pyrolysis balsa wood catalyst obtained in step (1) at a microwave power of 580 W, a temperature of 500° C., and a time of 1 h to obtain pyrolysis gas, pyrolysis oil, and pyrolysis char.

[0050] Example 3

[0051] This embodiment provides a method for resource recovery of waste carbon fiber wind turbine blades, the method comprising the following steps:

[0052] (1) Balsa wood was separated from waste carbon fiber fan blades, with a mass of 100 g of balsa wood, and then pyrolyzed at 500°C for 0.8 h. The resulting residue was ground and passed through a 200-mesh sieve to obtain mixed carbon; a potassium hydroxide solution with a solute concentration of 5 mol / L and the mixed carbon were evenly mixed, with the mass ratio of the mixed carbon to the potassium hydroxide solution being 5:9. After immersion for 13 h, solid-liquid separation was performed, and the resulting solid phase was vacuum dried at 82°C for 5 h to obtain a pyrolysis balsa wood catalyst;

[0053] (2) The waste carbon fiber fan blades after separation of balsa wood with a mass ratio of 8:1 were subjected to microwave co-pyrolysis treatment with the pyrolysis balsa wood catalyst obtained in step (1) at a microwave power of 620 W, a temperature of 500° C., and a time of 0.5 h to obtain pyrolysis gas, pyrolysis oil, and pyrolysis char.

[0054] Example 4

[0055] This embodiment provides a method for resource recovery of waste carbon fiber fan blades. The difference from Example 1 is that, except for adjusting the mass ratio of the waste carbon fiber fan blades after separation of balsa wood in step (2) to the pyrolysis balsa wood catalyst to 5:1, the rest is the same as Example 1.

[0056] Example 5

[0057] This embodiment provides a method for resource recovery of waste carbon fiber fan blades. The difference from Example 1 is that, except for adjusting the mass ratio of the waste carbon fiber fan blades after separation of balsa wood in step (2) to the pyrolysis balsa wood catalyst to 10:1, the rest is the same as Example 1.

[0058] Example 6

[0059] This embodiment provides a method for resource recovery of waste carbon fiber fan blades. The difference from Example 1 is that, except for adjusting the mass ratio of the waste carbon fiber fan blades after separation of balsa wood in step (2) to the pyrolysis balsa wood catalyst to 3:1, the rest is the same as Example 1.

[0060] Example 7

[0061] This embodiment provides a method for resource recovery of waste carbon fiber fan blades. The difference from Example 1 is that, except for adjusting the mass ratio of the waste carbon fiber fan blades after separation of balsa wood in step (2) to the pyrolysis balsa wood catalyst to 12:1, the rest is the same as Example 1.

[0062] Example 8

[0063] This embodiment provides a method for resource recovery of waste carbon fiber wind turbine blades. The difference from Example 1 is that, except for adjusting the temperature of the microwave co-pyrolysis treatment in step (2) to 400°C, the rest is the same as Example 1.

[0064] Example 9

[0065] This embodiment provides a method for resource recovery of waste carbon fiber wind turbine blades. The difference from Example 1 is that, except for adjusting the temperature of the microwave co-pyrolysis treatment in step (2) to 600°C, the rest is the same as Example 1.

[0066] Example 10

[0067] This embodiment provides a method for resource recovery of waste carbon fiber wind turbine blades. The difference from Example 1 is that, except for adjusting the temperature of the microwave co-pyrolysis treatment in step (2) to 350°C, the rest is the same as Example 1.

[0068] Example 11

[0069] This embodiment provides a method for resource recovery of waste carbon fiber wind turbine blades. The difference from Example 1 is that, except for adjusting the temperature of the microwave co-pyrolysis treatment in step (2) to 650° C., the rest is the same as Example 1.

[0070] Comparative Example 1

[0071] This comparative example provides a method for resource-recycling waste carbon fiber wind turbine blades. The difference from Example 1 is that the sodium hydroxide solution impregnation step in step (1) is omitted, and the rest is the same as Example 1.

[0072] Comparative Example 2

[0073] This comparative example provides a method for resource-based treatment of waste carbon fiber fan blades. The difference from Example 1 is that the microwave co-pyrolysis treatment in step (2) is replaced by electric heating tube furnace heating, and the rest is the same as Example 1.

[0074] The proportions of pyrolysis gas, pyrolysis oil, and pyrolysis char obtained in Examples 1-11 and Comparative Examples 1 and 2 were calculated, and the results are shown in Table 1. The reduction rates of pyrolysis energy consumption and pyrolysis oil content in Examples 1-11 and Comparative Example 1 compared with Comparative Example 2 were calculated, and the results are shown in Table 1.

[0075] Table 1

[0076] As can be seen from Table 1, the method for resource-based treatment of waste carbon fiber fan blades provided by the present application has a higher pyrolysis energy consumption reduction rate and a higher pyrolysis oil content reduction rate than conventional pyrolysis conditions, which is conducive to the rapid recovery of waste carbon fiber fan blades in the subsequent disposal process;

[0077] By comparing Example 1 with Examples 4-7, it can be seen that the mass ratio of the waste carbon fiber fan blades after separating the balsa wood and the pyrolysis balsa wood catalyst is within a reasonable range, the pyrolysis energy consumption reduction rate and the pyrolysis oil content reduction rate are high, and if the mass ratio exceeds the limited range, the pyrolysis oil content will not be significantly reduced; by comparing Example 1 with Examples 8-11, it can be seen that the temperature of the microwave co-pyrolysis treatment is within a reasonable range, which can make the pyrolysis heating more uniform, and at the same time, can fully convert the macromolecules in the pyrolysis process of the organic resin into small molecular combustible gas, thereby realizing the in-situ removal of tar in the microwave co-pyrolysis; if the temperature of the microwave co-pyrolysis treatment exceeds the limited range, the reduction in pyrolysis energy consumption or the reduction in pyrolysis oil content will be reduced;

[0078] By comparing Example 1 with Comparative Example 1, it can be seen that the balsa wood after pyrolysis is not modified with alkali solution, and the reduction rate of the pyrolysis oil content is low; by comparing Example 1 with Comparative Example 2, it can be seen that the pyrolysis energy consumption is significantly reduced and the pyrolysis oil content is significantly reduced when microwave co-pyrolysis is used compared with conventional electric heating tube furnace heating.

[0079] In summary, the method for resource recovery of waste carbon fiber fan blades provided by the present application makes full use of waste carbon fiber fan blades as raw materials, which can reduce the cost of waste fan blades in the disposal process; at the same time, mixed carbon, as a microwave energy absorbing material, can change the dielectric constant in waste carbon fiber fan blades, fully improve the microwave heating rate and the uniformity of pyrolysis heating, and further reduce the reaction energy consumption; the present application also utilizes the in-situ catalytic cracking of tar produced in the microwave co-pyrolysis process, which can fully convert the macromolecules in the organic resin pyrolysis process into small molecule combustible gas, and achieve the in-situ removal effect of the liquid product tar in the microwave co-pyrolysis reaction process, reducing the coking problem of subsequent pyrolysis equipment, and completely recovering the pyrolytic carbon while completely removing the organic components contained in the blades. Compared with conventional pyrolysis conditions, the pyrolysis energy consumption is reduced by 30.6%, and the pyrolysis oil content is reduced by 62.6%, which is conducive to the rapid recovery of resources in the subsequent disposal of waste carbon fiber fan blades, and expands the industrial application field method of microwave pyrolysis of waste carbon fiber.

[0080] The above description is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Those skilled in the art should understand that any changes or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for recycling waste carbon fiber fan blades, comprising the following steps: (1) separating balsa wood from waste carbon fiber fan blades, performing pyrolysis and alkali solution modification, and obtaining a pyrolysis balsa wood catalyst; (2) subjecting the waste carbon fiber fan blades after separation of balsa wood to microwave co-pyrolysis treatment with the pyrolysis balsa wood catalyst obtained in step (1) to obtain pyrolysis gas, pyrolysis oil and pyrolysis charcoal.

2. The method according to claim 1, wherein: The mass of the balsa wood in step (1) is 20-100g.

3. The method according to claim 1 or 2, wherein: The pyrolysis temperature in step (1) is 250-500°C.

4. The method according to any one of claims 1 to 3, wherein: The pyrolysis time in step (1) is 0.8-1.2h.

5. The method according to any one of claims 1 to 4, wherein: After the pyrolysis in step (1) and before the alkali solution modification, the method further includes the steps of grinding and screening; Optionally, the grinding and sieving are to grind the residue obtained after pyrolysis and sieve it through a 50-200 mesh sieve to obtain mixed carbon.

6. The method according to claim 5, wherein: The alkali solution modification step in step (1) comprises: uniformly mixing the alkali solution with the mixed carbon, separating the solid and the liquid after impregnation, and vacuum drying the obtained solid phase.

7. The method according to claim 6, wherein: The mass ratio of the mixed carbon to the alkali solution is (1-5):(2-10).

8. The method according to claim 6 or 7, wherein: The solute concentration of the alkali solution is 2-5 mol / L; Optionally, the alkali solution includes sodium hydroxide solution and / or potassium hydroxide solution; Optionally, the immersion time is 11-13 hours.

9. The method according to any one of claims 6 to 8, wherein: The vacuum drying temperature is 78-82°C.

10. The method according to any one of claims 6 to 9, wherein: The vacuum drying time is 5-7h.

11. The method according to any one of claims 1 to 10, wherein: The mass ratio of the waste carbon fiber fan blades after separation of balsa wood in step (2) to the pyrolysis balsa wood catalyst is (5-10):

1.

12. The method according to any one of claims 1 to 11, wherein: The microwave power of the microwave co-pyrolysis treatment in step (2) is 580-620W.

13. The method according to any one of claims 1 to 12, wherein: The temperature of the microwave co-pyrolysis treatment in step (2) is 400-600°C.

14. The method according to any one of claims 1 to 13, wherein: The time of the microwave co-pyrolysis treatment in step (2) is 0.5-1h.

15. The method according to any one of claims 1 to 14, comprising the steps of: (1) separating balsa wood from waste carbon fiber fan blades, the mass of balsa wood being 20-100 g, and then pyrolyzing at 250-500° C. for 0.8-1.2 h, grinding the obtained residue and passing it through a 50-200 mesh sieve to obtain mixed carbon; uniformly mixing an alkali solution having a solute concentration of 2-5 mol / L and the mixed carbon, wherein the mass ratio of the mixed carbon to the alkali solution is (1-5):(2-10), impregnating for 11-13 h, and then separating the solid and liquid, and vacuum drying the obtained solid phase at 78-82° C. for 5-7 h to obtain a pyrolysis balsa wood catalyst; (2) subjecting the waste carbon fiber fan blades after separation of balsa wood in a mass ratio of (5-10):1 to microwave co-pyrolysis treatment with the pyrolysis balsa wood catalyst obtained in step (1), with a microwave power of 580-620 W, a temperature of 400-600° C., and a time of 0.5-1 h to obtain pyrolysis gas, pyrolysis oil, and pyrolysis charcoal.

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