Recycling Method and System for Waste Wind Turbine Blades

Abstract

The present invention relates to the field of solid waste treatment, and discloses a recycling method and system for waste wind turbine blades. The method comprises the following steps: (1) crushing and pulverizing the waste wind turbine blades to obtain waste wind turbine blade fragments; (2) under the condition that the absolute pressure ≤ 100 Pa, carrying out a pyrolysis reaction on the waste wind turbine blade fragments to obtain pyrolysis gas and solid products, and then condensing the pyrolysis gas to obtain pyrolysis oil; (3) calcining the solid products. In this method, the pyrolysis reaction of the waste wind turbine blades has a high reaction degree, and the recovery rates of pyrolysis oil and glass fiber are high. At the same time, no toxic substances are generated, realizing more efficient and safe recycling of waste wind turbine blades.

Description

Technical Field

[0001] The present invention relates to the field of solid waste treatment, and particularly relates to a method and system for recycling waste wind turbine blades. Background Art

[0002] Wind turbine blades are one of the core components of wind turbines, which mainly contain thermosetting resin-based composites reinforced with glass fiber or mixtures, and also contain a certain amount of metals such as aluminum and copper, and a small amount of components such as epoxy structural adhesive and polyepoxy propane-based paint. The extensive promotion of wind power generation has put more wind turbine blades into use. Since the service life of wind turbine blades does not exceed 20 years, the early used wind turbine blades will face problems such as retirement or blade replacement, and a large number of waste wind turbine blades that need to be processed will appear. Therefore, how to recycle waste wind turbine blades is an urgent problem to be solved at present.

[0003] Currently, the commonly used method for recycling waste wind turbine blades is pyrolysis. In the actual pyrolysis process, the fine particles obtained after crushing the waste wind turbine blades are usually mixed with recycled high-temperature ash to meet the pyrolysis conditions. During the pyrolysis process, the flow of gas is always maintained, so that the waste wind turbine blade particles carry out pyrolysis reactions in the temperature range of 350 - 550 °C. However, there are many problems in this recycling process. Through research, it has been shown that the waste wind turbine blade particles are not sufficient for full pyrolysis in the temperature range of 350 - 550 °C. Therefore, during the pyrolysis of the resin in the waste wind turbine blades, there is a problem of incomplete pyrolysis reaction, which will lead to insufficient yields of pyrolysis oil and pyrolysis gas. On the other hand, in the prior art, the gas in the pyrolysis reaction chamber is air, and the waste wind turbine blade particles will burn violently in the oxygen-containing air. Finally, not only pyrolysis products cannot be obtained, but also toxic substance dioxin will be produced, seriously endangering human health. And dioxin must be eliminated when the combustion temperature reaches above 1500 °C, which also poses a problem for subsequent tail gas treatment. At the same time, after the waste wind turbine blades go through the crushing and pulverizing stage, the particle sizes of the waste wind turbine blade scraps containing resin components and the particles containing glass fiber components are very different. The particle size of the particles containing resin components is very small. When air is introduced during the pyrolysis reaction, after long-term operation, the reactor in the pyrolysis part has the risk of explosion. However, if an inert gas is introduced during pyrolysis, but finally the pyrolysis gas obtained from the pyrolysis reaction of the waste wind turbine blades needs to be recycled, so the introduced inert gas cannot be recycled for a long time, and this will also make the recycling cost of waste wind turbine blades extremely high. Summary of the Invention

[0004] The object of the present invention is to overcome the problems existing in the prior art, such as low degree of pyrolysis reaction during the recycling of waste wind turbine blades, easy generation of toxic substance dioxin, as well as complex existing recycling systems and high recycling costs. The present invention provides a method and a system for recycling waste wind turbine blades. In this method, the degree of pyrolysis reaction of waste wind turbine blades is high, the recovery rates of pyrolysis oil and glass fiber are high, and at the same time, no toxic gas is emitted, realizing more efficient and safe recycling of waste wind turbine blades.

[0005] To achieve the above object, on the one hand, the present invention provides a method for recycling waste wind turbine blades, the method comprising the following steps:

[0006] (1) Pretreating the waste wind turbine blades to obtain waste wind turbine blade scraps;

[0007] (2) Under the condition of absolute pressure ≤ 100 Pa, subjecting the waste wind turbine blade scraps to a pyrolysis reaction to obtain pyrolysis gas and solid products, and then condensing the pyrolysis gas to obtain pyrolysis oil;

[0008] (3) Calcining the solid products.

[0009] Preferably, the conditions of the pyrolysis reaction include: reaction temperature is 400 - 500 °C, and reaction time is 1 - 2 h.

[0010] Preferably, the temperature of the condensation is 5 - 25 °C.

[0011] Preferably, the temperature of the calcination is 600 - 800 °C, and the calcination time is 1 - 2 h.

[0012] Preferably, the pretreatment includes sequentially crushing and pulverizing the waste wind turbine blades to obtain waste wind turbine blade scraps;

[0013] Preferably, the particle size of the waste wind power generation blade scraps is ≤ 8 mm.

[0014] On the second aspect, the present invention provides a recycling system for waste wind turbine blades, the system comprising a sintering device and a pretreatment system, a pyrolysis reactor, a condensation device and a vacuum device connected in sequence;

[0015] The pretreatment system is used for pretreating the waste wind turbine blades to obtain waste wind turbine blade scraps;

[0016] The pyrolysis reactor is used for subjecting the waste wind turbine blade scraps to a vacuum pyrolysis reaction to obtain pyrolysis gas and solid products;

[0017] The condensation device is used for condensing the pyrolysis gas to obtain pyrolysis oil;

[0018] The vacuum device is used to control the absolute pressure in the pyrolysis reactor and the condensation device;

[0019] The sintering device is used to calcine the solid product to obtain glass fiber.

[0020] Preferably, the condensation device includes a condenser tube;

[0021] The condenser tube includes an inner tube and an outer tube sleeved outside the inner tube. A coiled tube in a spiral shape is arranged in the inner tube, and a packing layer is arranged between the inner tube and the coiled tube.

[0022] Preferably, the system further includes a pyrolysis oil collection device for collecting the pyrolysis oil condensed by the condenser tube.

[0023] Preferably, the packing in the packing layer is selected from multi-layer wire meshes and / or pumice.

[0024] Preferably, a rotary bed drying and adsorption system is arranged between the condensation device and the vacuum device, and the rotary bed drying and adsorption system is used to adsorb the gas discharged from the condenser tube.

[0025] Preferably, the pretreatment system includes a shredder, a pulverizer and a conveyor belt;

[0026] The shredder is used to crush the waste fan blade;

[0027] The pulverizer is used to pulverize the crushed waste fan blade to obtain waste fan blade fragments;

[0028] The conveyor belt is used to convey the waste fan blade fragments.

[0029] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0030] (1) The method described in the present invention thermally cracks the waste wind turbine blade scraps by means of vacuum cracking, allowing the waste wind turbine blade scraps to undergo thermal cracking reactions under certain vacuum conditions. This not only reduces the temperature of the thermal cracking reaction and shortens the time of the thermal cracking reaction, but also avoids the combustion reaction of the waste wind turbine blades with oxygen to generate dioxins, which is harmful to the health of operators. Moreover, the method described in the present invention can also fully thermally crack the organic substances such as resins in the waste wind turbine blades, condense the obtained pyrolysis gas to obtain products such as pyrolysis oil, and the obtained pyrolysis oil can be directly used as a high-temperature fuel. At the same time, the method described in the present invention can also recycle the glass fibers in the waste wind turbine blades, and the obtained glass fibers can also be directly used as fillers or as raw materials for fine alkali-free glass powder. The method has a high recovery rate of resins and glass fibers in the waste wind turbine blades and can resourcefully process the waste wind turbine blades as much as possible.

[0031] (2) The method described in the present invention can completely recycle the waste wind turbine blades without polluting the environment. Only a small amount of harmless gas is emitted during the entire recycling process, and the recycling method is green and environmentally friendly.

[0032] (3) The system structure described in the present invention is simple. There is no need to introduce gas from outside the system to meet the conditions required for the thermal cracking reaction. At the same time, a vacuum device is used to control the gas flow rate in the system, making it not easy to generate problems such as dust splashing and there being no safety hazards such as explosion.

[0033] (4) The method described in the present invention specifically controls the conditions of the thermal cracking reaction of the resins in the waste wind turbine blades and the doping during condensation, so as to ensure that the resins in the waste wind turbine blades are completely thermally cracked, ensure the quantity of the obtained pyrolysis gas and pyrolysis oil, and ensure the full recovery and utilization of the resins in the waste wind turbine blades. Description of the Drawings

[0034] Figure 1 is a schematic diagram of the waste wind turbine blade recycling system described in the present invention;

[0035] Figure 2 is a schematic diagram of the structure of the condenser tube described in the present invention.

[0036] Description of the Reference Numerals

[0037] 1 Pretreatment system; 2 Pyrolysis reactor; 3 Condensing device; 4 Pyrolysis oil collection device; 5 Rotary bed drying and adsorption system; 6 Vacuum device; 7 Sintering device; 31 Inner tube of the condenser tube; 32 Outer tube of the condenser tube; 33 Coiled tube of the condenser tube; 34 Packing layer of the condenser tube; 35 Circulating water inlet; 36 Circulating water outlet; 37 Pyrolysis oil outlet; 38 Pyrolysis gas inlet; 39 Tail gas outlet. Detailed Embodiments

[0038] The following is a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0039] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0040] In the present invention, the content of glass fiber in the waste wind turbine blade is 65%-75%, and the content of resin is 25%-35%.

[0041] In the present invention, the "pyrolysis reaction" refers to a process in which the molecular chain of a high molecular polymer breaks to generate small molecule organic substances under certain temperature conditions for organic substances.

[0042] The present invention provides a method for recycling waste wind turbine blades, and the method includes the following steps:

[0043] (1) Pretreat the waste wind turbine blade to obtain waste wind turbine blade scraps;

[0044] (2) Under the condition that the absolute pressure ≤ 100 Pa, carry out a pyrolysis reaction on the waste wind turbine blade scraps to obtain pyrolysis gas and solid products, and then condense the pyrolysis gas to obtain pyrolysis oil;

[0045] (3) Calcinate the solid product.

[0046] In the method of the present invention, in order to facilitate the pyrolysis reaction of organic substances such as resin in the waste wind turbine blade, the waste wind turbine blade is pretreated. The specific steps of the pretreatment include successively crushing and pulverizing the waste wind turbine blade, and controlling the particle size of the obtained waste wind turbine blade scraps ≤ 8 mm, for example, it can be 4 mm - 6 mm.

[0047] In a specific embodiment, carrying out pyrolysis on the waste wind turbine blade scraps under a vacuum condition can prevent components such as resin in the waste wind turbine blade from burning to produce dioxin, and control the absolute pressure of the system during the pyrolysis ≤ 100 Pa, for example, it can be 1 Pa - 100 Pa.

[0048] In the method of the present invention, in order to allow the resin in the waste wind turbine blade to undergo sufficient pyrolysis, control the reaction temperature of the pyrolysis reaction to be 400 - 500 °C and the reaction time to be 1 - 2 h.

[0049] In a preferred embodiment, the reaction temperature for controlling the pyrolysis reaction is 410 - 470 °C, and the reaction time is 1.5 - 2 h. Specifically, the reaction temperature of the pyrolysis reaction can be 410 °C, 430 °C, 450 °C, or 470 °C; the reaction time can be 1 h, 1.5 h, or 2 h.

[0050] In the method of the present invention, in step (2), the waste wind turbine blade scraps are subjected to a pyrolysis reaction under a vacuum state, which can effectively avoid the intense combustion of waste wind turbine blades in oxygen to generate dioxins. At the same time, under the pressure conditions and pyrolysis temperature conditions of the present invention, it can ensure that the organic substances such as resins in the waste wind turbine blades are fully pyrolyzed completely, ensuring the maximum recovery of the organic substances in the waste wind turbine blades. There is a close relationship between the range of the absolute pressure defined in the present invention and the temperature and time of pyrolysis, jointly ensuring the degree of pyrolysis of the organic substances in the waste wind turbine blades, thereby ensuring the yield of the pyrolysis oil obtained.

[0051] In the method of the present invention, in order to collect and reuse the pyrolysis gas obtained from the pyrolysis reaction of the waste wind turbine blades as much as possible, the pyrolysis gas is condensed to obtain pyrolysis oil, and the condensation temperature is 5 - 25 °C, preferably 10 - 20 °C. Specifically, the condensation temperature can be 5 °C, 10 °C, 15 °C, 20 °C, or 25 °C.

[0052] In the method of the present invention, the pressure during the condensation of the pyrolysis gas is also in a vacuum state, which is more conducive to the rapid condensation of the pyrolysis gas.

[0053] In the method of the present invention, the pyrolysis oil obtained by condensation can be used as an energy supply substance for the subsequent calcination process of the solid product, or can be collected and used as a high-temperature fuel or chemical raw material.

[0054] In the method of the present invention, after the pyrolysis reaction is completed, when the pyrolysis reaction temperature drops below 70 °C, the solid product obtained from the pyrolysis reaction is taken out and calcined to remove the carbon-containing compounds and residual carbon attached to the surface of the solid product generated during the pyrolysis reaction. The pressure of the calcination is normal pressure, and the atmosphere during calcination is air. In the present invention, the calcination temperature is 600 - 800 °C, preferably 600 - 700 °C, more preferably 625 °C, and the calcination time is 1 - 2 h. Specifically, the calcination temperature can be 600 °C, 625 °C, 650 °C, 700 °C, 750 °C, or 800 °C; the calcination time can be 1 h, 1.5 h, or 2 h.

[0055] In the method of the present invention, the solid product is calcined to obtain a glass fiber product, and the recycled glass fiber product can be used as a raw material for fine alkali-free glass powder or for preparing other chemicals.

[0056] According to the first specific embodiment of the method of the present invention, the method comprises the following steps:

[0057] (1) Crushing and pulverizing the waste wind turbine blades to obtain waste wind turbine blade fragments;

[0058] (2) Under the condition of an absolute pressure ≤ 100 Pa, subjecting the waste wind turbine blade fragments to a pyrolysis reaction to obtain pyrolysis gas and a solid product, and then condensing the pyrolysis gas to obtain pyrolysis oil;

[0059] (3) Calcining the solid product;

[0060] The conditions of the pyrolysis reaction include: a reaction temperature of 400 - 500 °C and a reaction time of 1 - 2 h.

[0061] According to another specific embodiment of the method of the present invention, the method comprises the following steps:

[0062] (1) Crushing and pulverizing the waste wind turbine blades to obtain waste wind turbine blade fragments;

[0063] (2) Under the condition of an absolute pressure ≤ 100 Pa, subjecting the waste wind turbine blade fragments to a pyrolysis reaction to obtain pyrolysis gas and a solid product, and then condensing the pyrolysis gas to obtain pyrolysis oil;

[0064] (3) Calcining the solid product;

[0065] The conditions of the pyrolysis reaction include: a reaction temperature of 400 - 500 °C and a reaction time of 1 - 2 h;

[0066] The temperature of the condensation is 5 - 25 °C.

[0067] The present invention further provides a recycling system for waste wind turbine blades, the system comprising a sintering device 7 and a pretreatment system 1, a pyrolysis reactor 2, a condensation device 3 and a vacuum device 6 connected in sequence;

[0068] The pretreatment system 1 is used for pretreating the waste wind turbine blades to obtain waste wind turbine blade fragments;

[0069] The pyrolysis reactor 2 is used for subjecting the waste wind turbine blade fragments to a vacuum pyrolysis reaction to obtain pyrolysis gas and a solid product;

[0070] The condensation device 3 is used for condensing the pyrolysis gas to obtain pyrolysis oil;

[0071] The vacuum device 6 is used to control the absolute pressure in the pyrolysis reactor 2 and the condensation device 3;

[0072] The sintering device 7 is used to calcine the solid product to obtain glass fibers.

[0073] In the system of the present invention, the pretreatment system 1 includes a shredder, a pulverizer and a conveyor connected in sequence; the shredder is used to crush the waste wind turbine blades, and the crushed waste wind turbine blades are conveyed into the pulverizer; the pulverizer is used to pulverize the crushed waste wind turbine blades to obtain waste wind turbine blade scraps, and the waste wind turbine blade scraps are conveyed into the pyrolysis reactor 2 through the conveyor for vacuum pyrolysis reaction.

[0074] In the system of the present invention, the pyrolysis reactor 2 includes a reaction chamber, a heating device, a temperature control device and a cooling device; the reaction chamber is used to provide a place for the pyrolysis reaction of the waste wind turbine blades; the heating device is used to heat the reaction chamber; the temperature control device is used to control the temperature of the reaction chamber; the cooling device is used to cool the reaction chamber. The pyrolysis reactor 2 can be a device commonly used in the art and will not be elaborated here.

[0075] In the system of the present invention, the condensation device 3 includes a condensation pipe, and the structural schematic diagram of the condensation pipe is as Figure 2 shown. The condensation pipe includes an inner pipe 31 and an outer pipe 32 sleeved outside the inner pipe. A coiled pipe 33 in a spiral shape is arranged in the inner pipe, and a packing layer 34 is arranged between the inner pipe and the coiled pipe; a circulating water inlet 35, a circulating water outlet 36, a pyrolysis gas inlet 38, a pyrolysis oil outlet 37 and a tail gas outlet 39 are arranged on the condensation pipe.

[0076] In a specific embodiment, in the condenser tube of the present invention, the cooling medium is circulating water, which is provided by a circulating chiller. The circulating water enters the condenser tube from the circulating water inlet 35, and circulates and exchanges heat in the region between the inner tube 31 and the outer tube 32 and inside the spiral coiled tube 33. The circulating water after heat exchange is discharged from the circulating water outlet 36. In addition, the pyrolysis gas obtained from the pyrolysis reactor 2 is transported through the pyrolysis gas inlet 38 to the region between the inner tube 31 and the coiled tube 33 to exchange heat with the circulating water. The temperature of the pyrolysis gas decreases, and some substances in the pyrolysis gas are condensed. The condensed substances are transported through the pyrolysis oil outlet 37 to the pyrolysis oil collection device 4 for collection to obtain pyrolysis oil. The uncondensed part of the gas in the pyrolysis gas is discharged through the tail gas outlet 39 and then transported to the rotary bed drying and adsorption system 5 for adsorption. The condenser tube of the present invention has a fast condensation speed for the pyrolysis gas and a large condensation area, and can realize rapid heat exchange between the pyrolysis gas and the cooling medium to reduce the temperature of the pyrolysis gas. In addition, a packing layer 34 is provided between the inner tube 31 and the coiled tube 33 of the condenser tube of the present invention. When the pyrolysis gas passes through the packing layer 34, the packing layer 34 can extend the residence time of the pyrolysis gas in the condenser tube and slow down the gas flow rate of the pyrolysis gas, thereby improving the heat exchange efficiency between the pyrolysis gas and the cooling medium and preventing the pyrolysis oil from being drawn out.

[0077] In a preferred embodiment, the packing in the packing layer 34 is selected from multi-layer wire meshes and / or pumice.

[0078] In the system of the present invention, the system further includes a pyrolysis oil collection device 4 for collecting the pyrolysis oil condensed by the condenser tube.

[0079] In the system of the present invention, in the condenser tube, the packing layer 34 is arranged at the top of the condenser tube, upstream of the tail gas outlet 39 along the gas flow direction. The thickness of the packing layer 34 is 5 - 7 cm and does not fill the entire inner cavity of the condenser tube.

[0080] In the system of the present invention, a rotary bed drying and adsorption system 5 is arranged between the condensing device 3 and the vacuum device 6. The rotary bed drying and adsorption system 5 is used for adsorbing the gas discharged from the condenser tube, and the rotary bed drying system 5 is connected to the tail gas outlet 39 of the condenser tube.

[0081] In the system of the present invention, the gas discharged from the condenser is the gas in the pyrolysis gas that has not been condensed in the condenser. The pyrolysis gas obtained by pyrolyzing waste wind turbine blades contains a part of small-molecule organic compounds with C1-C4. Due to their low condensation temperature, they are not easily condensed into liquid for collection in the condensation device 3. Therefore, a rotary bed drying and adsorption system 5 is used to adsorb and collect this part of small-molecule organic compounds. On the one hand, it can reduce the emission of polluting gases in the system of the present invention, and on the other hand, it can also collect and reuse the small-molecule organic compounds, further enhancing the utilization value of waste wind power blades.

[0082] In a specific embodiment, the rotary bed drying and adsorption system 5 includes an adsorption unit, a desorption unit, and a cooling unit; the adsorption unit contains an adsorbent, and the adsorbent is used to adsorb the gas processed by the condensation device 3; the desorption unit is used to desorb the adsorbent after adsorbing the gas; the cooling unit is used to cool and regenerate the desorbed adsorbent, and the regenerated adsorbent is transported to the adsorption unit for reuse.

[0083] In the system of the present invention, the desorption method of the desorption unit in the rotary bed drying and adsorption system 5 is to heat and desorb the adsorbent after adsorbing the gas with a small amount of hot air, and the desorbed gas can be collected and reused.

[0084] In a specific embodiment, after the adsorbent in the adsorption unit of the rotary bed drying and adsorption system 5 adsorbs the pyrolysis gas processed by the condensation device 3, the adsorbed adsorbent is sent to the desorption unit, and a small amount of hot air is used to desorb the adsorbent after adsorbing the gas. The desorbed gas is collected, and the desorbed adsorbent is sent to the cooling unit for cooling and regeneration. The regenerated adsorbent is transported to the adsorption unit for reuse.

[0085] In the system of the present invention, the adsorbent in the rotary bed drying and adsorption system 5 can be an adsorbent material commonly used in the art that can adsorb small-molecule organic compound gases and can be regenerated.

[0086] In the system of the present invention, the vacuum device 6 includes a vacuum pump, and the vacuum pump can be a commonly used vacuum pump in the art.

[0087] In a specific embodiment, the vacuum device 6 is used to simultaneously adjust the vacuum environment in the pyrolysis reactor 2, the condensation device 3, and the rotary bed drying system 5, and the pyrolysis reactor 2, the condensation device 3, and the rotary bed drying system 5 are interconnected with the vacuum device 6.

[0088] In the system of the present invention, the sintering device 7 includes a sintering furnace. The pressure inside the sintering device 7 is normal pressure, and the atmosphere inside the sintering furnace is air. The sintering furnace can be of the common types of sintering furnaces in the art.

[0089] In the system of the present invention, the pyrolysis oil obtained by the pyrolysis oil collection device 4 can be transported to the sintering device 7, and the pyrolysis oil is burned to provide energy for the calcination of solid products.

[0090] In a specific embodiment, the shredder in the pretreatment system 1 is connected to the pulverizer. The pyrolysis reactor 2 is provided with a raw material inlet and a solid product outlet. The pulverizer is connected to the raw material inlet of the pyrolysis reactor 2. The pyrolysis reactor 2 is connected to the condenser through the pyrolysis gas inlet 38 of the condenser tube; the pyrolysis oil outlet 37 of the condenser tube is connected to the pyrolysis oil collection device 4; the tail gas outlet 39 of the condenser tube is connected to the rotary bed drying and adsorption system 5. The vacuum device 6 is communicated with the rotary bed drying system 5. The solid product outlet of the pyrolysis reactor 2 is connected to the sintering device 7.

[0091] The working principle of the system of the present invention is as follows: The waste wind turbine blade is crushed in the shredder in the pretreatment system 1, and then pulverized in the pulverizer to obtain waste wind turbine blade scraps; the waste wind turbine blade scraps are transported to the pyrolysis reactor 2, and the vacuum device 6 is started to reduce the system pressure in the pyrolysis reactor 2, the condensation device 3 and the rotary bed drying and adsorption system 5, so that the pyrolysis reactor 2, the condensation device 3 and the rotary bed drying and adsorption system 5 are in a vacuum environment; then the waste wind turbine blade scraps carry out a vacuum pyrolysis reaction in the pyrolysis reactor 2. After the reaction, pyrolysis gas and solid products are obtained; the pyrolysis gas is transported to the condenser tube of the condensation device 3 for cooling and condensation, and the pyrolysis oil collection device 4 is used to collect the condensed pyrolysis oil. Then the uncondensed gas in the pyrolysis gas is transported through the tail gas outlet 39 of the condenser tube to the adsorption unit in the rotary bed drying and adsorption system 5. The adsorbent in the adsorption unit is used to adsorb the gas. The adsorbed adsorbent is sent to the desorption unit, and a small amount of hot air is used to desorb the adsorbent that has adsorbed the gas. The desorbed gas is collected and the desorbed adsorbent is sent to the cooling unit for cooling and regeneration. The regenerated adsorbent is transported to the adsorption unit for reuse;

[0092] The solid product is transported through the solid product outlet of the pyrolysis reactor 2 to the sintering device 6 for calcination, and a glass fiber product is obtained after removing the surface carbon-containing compounds and residual carbon.

[0093] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0094] The following examples are implemented in the waste wind turbine blade recycling system shown in Figure 1 The system includes a sintering device 7 and a pretreatment system 1, a pyrolysis reactor 2, a condensation device 3, a pyrolysis oil collection device 4, a rotary bed drying and adsorption system 5, and a vacuum device 6 that are connected in sequence;

[0095] The pretreatment system 1 includes a shredder, a pulverizer, and a conveyor belt;

[0096] The pyrolysis reactor 2 includes a reaction chamber, a heating device, a temperature control device, and a cooling device;

[0097] The condensation device 3 includes a condenser tube, and the structural schematic diagram of the condenser tube is as shown in Figure 2 shown;

[0098] The rotary bed drying and adsorption system 5 includes an adsorption unit, a desorption unit, and a cooling unit;

[0099] The vacuum device 6 includes a vacuum pump;

[0100] The sintering device 7 includes a sintering furnace;

[0101] In the pretreatment system 1, the shredder is connected to the pulverizer, the pulverizer is connected to the raw material inlet of the pyrolysis reactor 2, and the pyrolysis reactor 2 is connected to the condenser tube through the pyrolysis gas inlet 38 of the condenser tube 31; the pyrolysis oil outlet 37 of the condenser tube is connected to the pyrolysis oil collection device 4; the tail gas outlet 39 of the condenser tube is connected to the rotary bed drying and adsorption system 5, the vacuum device 6 is connected to the rotary bed drying system 5, and the solid product outlet of the pyrolysis reactor 2 is connected to the sintering device 7.

[0102] Example 1

[0103] (1) Crush the waste wind turbine blade (resin content 30%, glass fiber content 70%) in the shredder of the pretreatment system 1, and then pulverize it in the pulverizer to obtain waste wind turbine blade scraps (particle size ≤ 8 mm);

[0104] (2) Feed the waste wind turbine blade scraps into the pyrolysis reactor 2. Start the vacuum pump of the vacuum system 6 to reduce the absolute pressure in the pyrolysis reactor 2, the condensation device 3, and the rotary bed drying and adsorption system 5 to 50 Pa. Then, the waste wind turbine blade scraps undergo pyrolysis reaction in the pyrolysis reactor 2 at a temperature of 400 °C for 2 h to obtain pyrolysis gas and solid products. Next, convey the pyrolysis gas to the condenser tubes of the condensation device 3 for cooling and condensation at a condensation temperature of 10 °C. Use the pyrolysis oil collection device 4 to collect the condensed pyrolysis oil. Then, convey the uncondensed gas in the pyrolysis gas to the adsorption unit in the rotary bed drying and adsorption system 5. Use the adsorbent in the adsorption unit to adsorb the gas. Send the adsorbed adsorbent to the desorption unit, and use a small amount of hot air to desorb the adsorbent that has adsorbed the gas. Collect the desorbed gas and send the desorbed adsorbent to the cooling unit for cooling and regeneration. The regenerated adsorbent is conveyed back to the adsorption unit for reuse;

[0105] (3) Convey the solid products to the sintering furnace of the sintering system 7 for calcination at a calcination temperature of 600 °C for 2 h to obtain glass fiber products.

[0106] Example 2

[0107] (1) Crush the waste wind turbine blades (resin content 30%, glass fiber content 70%) in the shredder of the pretreatment system 1, and then pulverize them in the pulverizer to obtain waste wind turbine blade scraps (particle size ≤ 8 mm);

[0108] (2) Feed the waste wind turbine blade scraps into the pyrolysis reactor 2. Start the vacuum pump of the vacuum system 6 to reduce the absolute pressure in the pyrolysis reactor 2, the condensation device 3, and the rotary bed drying and adsorption system 5 to 90 Pa. Then, the waste wind turbine blade scraps undergo pyrolysis reaction in the pyrolysis reactor 2 at a temperature of 450 °C for 1.5 h to obtain pyrolysis gas and solid products. Next, convey the pyrolysis gas to the condenser tubes of the condensation device 3 for cooling and condensation at a condensation temperature of 20 °C. Use the pyrolysis oil collection device 4 to collect the condensed pyrolysis oil. Then, convey the uncondensed gas in the pyrolysis gas to the adsorption unit in the rotary bed drying and adsorption system 5. Use the adsorbent in the adsorption unit to adsorb the gas. Send the adsorbed adsorbent to the desorption unit, and use a small amount of hot air to desorb the adsorbent that has adsorbed the gas. Collect the desorbed gas and send the desorbed adsorbent to the cooling unit for cooling and regeneration. The regenerated adsorbent is conveyed back to the adsorption unit for reuse;

[0109] (3) Transfer the solid product to the sintering furnace of the sintering system 7 for calcination at a calcination temperature of 650 °C for 1.5 h to obtain a glass fiber product.

[0110] Example 3

[0111] (1) Crush the waste wind turbine blade (resin content 30%, glass fiber content 70%) in the shredder of the pretreatment system 1, and then pulverize it in a pulverizer to obtain waste wind turbine blade scraps (particle size ≤ 8 mm);

[0112] (2) Transfer the waste wind turbine blade scraps to the pyrolysis reactor 2, start the vacuum pump of the vacuum system 6, reduce the absolute pressure in the pyrolysis reactor 2, the condensation device 3, and the rotary bed drying and adsorption system 5 to 40 Pa, and then the waste wind turbine blade scraps undergo a pyrolysis reaction in the pyrolysis reactor 2 at a pyrolysis reaction temperature of 500 °C for 1 h to obtain pyrolysis gas and a solid product. Then, transfer the pyrolysis gas to the condenser tube of the condensation device 3 for cooling and condensation at a condensation temperature of 15 °C, collect the pyrolysis oil obtained by condensation using the pyrolysis oil collection device 4, and then transfer the uncondensed gas in the pyrolysis gas to the adsorption unit in the rotary bed drying and adsorption system 5. Use the adsorbent in the adsorption unit to adsorb the gas, send the adsorbed adsorbent to the desorption unit, desorb the adsorbent that has adsorbed the gas with a small amount of hot air, collect the desorbed gas, and send the desorbed adsorbent to the cooling unit for cooling and regeneration. The regenerated adsorbent is transferred to the adsorption unit for reuse;

[0113] (3) Transfer the solid product to the sintering furnace of the sintering system 7 for calcination at a calcination temperature of 700 °C for 1.5 h to obtain a glass fiber product.

[0114] Example 4

[0115] Carry out the method according to Example 1, except that in step (2), the pyrolysis temperature is 350 °C.

[0116] Example 5

[0117] Carry out the method according to Example 1, except that in step (2), the pyrolysis temperature is 550 °C.

[0118] Comparative Example 1

[0119] Carry out the method according to Example 1, except that in step (2), do not start the vacuum pump of the vacuum device 5, and the absolute pressure in the pyrolysis reactor 2, the condensation device 3, and the rotary bed drying and adsorption system 4 is normal pressure.

[0120] Comparative Example 2

[0121] It is implemented according to the method of Example 1, except that in step (2), the vacuum device 6 reduces the absolute pressure in the pyrolysis reactor 2, the condensation device 3, and the rotary bed drying and adsorption system 5 to 200 Pa.

[0122] Test Example

[0123] Calculate the recovery rates of the resin and glass fiber in the waste wind turbine blades based on the yields of the pyrolysis oil and glass fiber obtained from Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1.

[0124] Table 1

[0125]

[0126]

[0127] It can be seen from the results in Table 1 that the method of the present invention can recycle waste wind turbine blades, and both the resin and glass fiber in the waste wind turbine blades have high recovery rates. Moreover, the recovery system of the present invention is simple, and no toxic substances are generated during the recovery process, having great industrial application prospects.

[0128] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for recycling waste wind turbine blades, characterized in that, the method comprises the following steps: (1) Pretreating the waste wind turbine blades to obtain waste wind turbine blade scraps; (2) Under the condition of an absolute pressure of 50 - 100 Pa, subjecting the waste wind turbine blade scraps to a pyrolysis reaction to obtain pyrolysis gas and solid products, and then condensing the pyrolysis gas to obtain pyrolysis oil; (3) Calcining the solid products; the reaction temperature of the pyrolysis reaction is 410 - 470 °C, and the reaction time is 1.5 - 2 h; the method is implemented in a waste wind turbine blade recycling system, which includes a sintering device (7) and a pretreatment system (1), a pyrolysis reactor (2), a condensation device (3), and a vacuum device (6) connected in sequence; the pretreatment system (1) is used to pretreat the waste wind turbine blades to obtain waste wind turbine blade scraps; the pyrolysis reactor (2) is used to subject the waste wind turbine blade scraps to a vacuum pyrolysis reaction to obtain pyrolysis gas and solid products; the condensation device (3) is used to condense the pyrolysis gas to obtain pyrolysis oil; the vacuum device (6) is used to control the absolute pressure in the pyrolysis reactor (2) and the condensation device (3); the sintering device (7) is used to calcine the solid products to obtain glass fibers; A rotary bed drying and adsorption system (5) is arranged between the condensation device (3) and the vacuum device (6), and the rotary bed drying and adsorption system (5) is used to adsorb the gas discharged from the condenser tubes of the condensation device (3); The system further includes a pyrolysis oil collection device (4) for collecting the pyrolysis oil condensed by the condenser tubes of the condensation device (3); The rotary bed drying and adsorption system (5) includes an adsorption unit, a desorption unit, and a cooling unit; the adsorption unit contains an adsorbent, and the adsorbent is used to adsorb the gas treated by the condensation device (3); the desorption unit is used to desorb the adsorbent after adsorbing the gas; the cooling unit is used to cool and regenerate the desorbed adsorbent, and the regenerated adsorbent is transported to the adsorption unit for reuse.

2. The method for recycling waste wind turbine blades according to claim 1, characterized in that, the temperature of the condensation is 5 - 25 °C.

3. The method for recycling waste wind turbine blades according to claim 1, characterized in that, the temperature of the calcination is 600 - 800 °C, and the calcination time is 1 - 2 h.

4. The method for recycling waste wind turbine blades according to claim 1, characterized in that, the pretreatment includes successively crushing and pulverizing the waste wind turbine blades to obtain waste wind turbine blade scraps.

5. The method for recycling waste wind turbine blades according to claim 1, characterized in that, the particle size of the waste wind turbine blade scraps ≤ 8 mm.

6. The method for recycling waste wind turbine blades according to claim 1, characterized in that, The condenser tube of the condenser device (3) includes an inner tube (31) and an outer tube (32) sleeved outside the inner tube. A coiled tube (33) in a spiral shape is provided in the inner tube, and a packing layer (34) is provided between the inner tube and the coiled tube.

7. The recycling method of waste wind turbine blades according to claim 6, characterized in that the packing in the packing layer (34) is selected from multi-layer wire meshes and / or pumice.

8. The recycling method of waste wind turbine blades according to claim 1, characterized in that the pretreatment system (1) includes a shredder, a pulverizer and a conveyor belt; the shredder is used for crushing the waste wind turbine blades; the pulverizer is used for pulverizing the crushed waste wind turbine blades to obtain waste wind turbine blade scraps; the conveyor belt is used for conveying the waste wind turbine blade scraps.

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