A green and low-energy wind turbine blade recycling system and method

Abstract

The present application discloses a green and low-energy wind turbine blade recycling system and method, which includes the following steps: (1) cutting the waste wind turbine blades after removing the metal components into blocks; (2) subjecting the waste wind turbine blades cut into blocks to a pyrolysis reaction in a pyrolysis atmosphere, wherein the pyrolysis atmosphere is a mixed gas composed of nitrogen, oxygen and ammonia, and pure glass fibers are obtained after the pyrolysis reaction; (3) after the pyrolysis tail gas is cooled, dust and denitrification are carried out in a bag filter with an integrated filter bag for dust removal and denitrification, and then the gas is discharged. The present invention can complete the pyrolysis of blades at a relatively low temperature through the design of the pyrolysis atmosphere, and is helpful to improve the quality of the recycled fiber. Dust removal and denitrification are carried out through the bag filter, so the blade recycling technology disclosed in the present invention has the advantage of being green and environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste treatment, and in particular, the present invention relates to a green and low-energy wind turbine blade recycling system and method. Background Art

[0002] Waste wind turbine blades are a kind of high value-added industrial solid waste that has emerged in the process of new energy development. At present, the main way to deal with waste blades is landfill, but with the increasingly stringent environmental protection policies, this method will be banned. Pyrolysis is a method for recycling resin-based composite materials. It usually converts the matrix resin of the composite material into gaseous small molecular compounds and pyrolytic carbon under a specific atmosphere and high temperature (≥850℃) to recover the reinforcing fibers with higher added value to achieve resource utilization. The main material of wind turbine blades is glass fiber reinforced epoxy resin composite materials. Therefore, this method can be used for the recycling of wind turbine blades. It is easy to scale and has broad application prospects. However, due to the use of a large amount of small molecule amine curing agents (amine value is about 600mg KOH / g, and the mass fraction accounts for more than 20% of the resin) in the blade molding, the pyrolysis exhaust contains a large amount of NO x , which can easily cause air pollution. In addition, the traditional pyrolysis method requires high temperature and high energy consumption in the blade recycling process. Therefore, the development of green and low-energy pyrolysis technology is of great significance for the recycling of waste wind turbine blades. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, an embodiment of the present invention proposes to provide a green and low-energy wind turbine blade recycling system and method.

[0004] A low-energy wind turbine blade recycling method according to an embodiment of the present invention comprises the following steps:

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

[0006] (2) subjecting the waste wind turbine blades cut into blocks to a pyrolysis reaction in a pyrolysis atmosphere, wherein the pyrolysis atmosphere is a mixed gas consisting of nitrogen, oxygen and ammonia, and obtaining pure glass fibers after the pyrolysis reaction;

[0007] (3) After the pyrolysis exhaust gas is cooled, it is subjected to dust removal and denitrification in a bag filter equipped with an integrated filter bag for dust removal and denitrification, and then discharged.

[0008] In some embodiments, the volume fraction of oxygen in the pyrolysis atmosphere is between 6% and 8%.

[0009] In some embodiments, the pyrolysis reaction is carried out in a pyrolysis furnace, the pyrolysis temperature is 400° C. to 420° C., and the pyrolysis time is 3 h to 4 h.

[0010] In some embodiments, the molar ratio of the ammonia concentration in the pyrolysis furnace to the nitrogen oxide concentration in the pyrolysis tail gas is controlled between 0.8 and 1.0.

[0011] In some embodiments, before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis exhaust gas through a heat exchanger and then enters the pyrolysis furnace after preheating.

[0012] In some embodiments, the pyrolysis tail gas is cooled to between 200°C and 220°C after heat exchange in a heat exchanger.

[0013] In some embodiments, the dust removal and denitration integrated filter bag is a low-temperature denitration catalyst MnO x -CeO2 is loaded on a conventional polytetrafluoroethylene filter bag; wherein, MnO x It accounts for 30% of the total mass of the catalyst, CeO2 accounts for 70% of the total mass of the catalyst, and the mass fraction of the catalyst on the filter bag accounts for 63% to 65%.

[0014] In some embodiments, the integrated dust removal and denitrification filter bag is prepared by a method comprising the following steps: manganese acetate and cerium nitrate are used as precursors of manganese oxide and cerium oxide, respectively, and the equimolar conversion of metal elements is performed according to the corresponding oxide content in the catalyst to calculate the corresponding amount of precursors, and perfluorosulfonic acid-polytetrafluoroethylene copolymer is used as a coupling agent, the amount of the coupling agent accounts for 30% of the mass of the impregnation solution, and an impregnation solution is made with water, a conventional polytetrafluoroethylene filter bag is impregnated, and then it is dried at 100°C for 2 hours, and then calcined at 400°C for 2 hours to prepare it.

[0015] In some embodiments, the size of the waste wind turbine blades cut into blocks is ≤10 cm in length and ≤10 cm in width.

[0016] The embodiment of the present invention further provides a low-energy consumption wind turbine blade recovery system, comprising:

[0017] A pyrolysis furnace, wherein the pyrolysis furnace has a feed inlet, a discharge port, a pyrolysis atmosphere inlet and a tail gas outlet;

[0018] A heat exchanger, wherein the heat exchanger has a hot side inlet, a hot side outlet, a cold side inlet and a cold side outlet, wherein the hot side inlet is connected to the tail gas outlet of the pyrolysis furnace through a pipeline, and the cold side inlet is connected to the pyrolysis atmosphere source inlet pipe; and the cold side outlet is connected to the pyrolysis atmosphere inlet of the pyrolysis furnace through a pipeline;

[0019] A bag-type dust collector is provided with a plurality of filter bags, wherein the filter bags are integrated filter bags for dust removal and denitrification; the bag-type dust collector has a gas inlet and a gas outlet, and the gas inlet is connected to the hot side outlet of the heat exchanger through a pipeline.

[0020] In some embodiments, the heat exchanger is a tubular heat exchanger.

[0021] Compared with the related art, the present invention has the following beneficial effects:

[0022] (1) Traditional pyrolysis methods usually require high temperatures, resulting in high energy consumption for blade processing. The present invention can complete blade pyrolysis at a lower temperature through the design of pyrolysis atmosphere, recover high value-added glass fibers, and has the advantage of low energy consumption for blade recovery.

[0023] (2) The present invention creatively adds ammonia to the pyrolysis atmosphere. On the one hand, it can be used as a reducing agent for subsequent low-temperature denitrification. In addition, its addition to the pyrolysis atmosphere also plays a role in preheating and premixing, which helps to reduce the escape of denitrification ammonia. On the other hand, ammonia can dilute the combustible gas in the pyrolysis gas, prevent deflagration and reduce the release of smoke, thereby helping to improve the quality of the recovered fiber and reduce the subsequent flue gas purification costs.

[0024] (3) In the present invention, the pyrolysis process releases heat, and the temperature of the pyrolysis tail gas is relatively high. A heat exchange unit is provided in the recovery process to recover part of the heat of the pyrolysis tail gas for heating the inlet gas of the pyrolysis furnace, thereby realizing waste heat utilization and reducing the heating energy consumption of the pyrolysis furnace.

[0025] (4) The present invention sets a bag filter with integrated dust removal and denitration filter bags at the outlet of the pyrolysis furnace to denitrate the tail gas at a relatively low temperature, and at the same time removes a small amount of (cracking) carbon powder and impurity dust in the tail gas caused by continuous ventilation, thereby avoiding secondary air pollution caused by the pyrolysis tail gas. Therefore, the blade recovery technology disclosed in the present invention has the advantage of being green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 It is a schematic diagram of a low-energy wind turbine blade recovery system of the present invention;

[0028] Reference numerals:

[0029] 1 is a pyrolysis furnace, 2 is a heat exchanger, and 3 is a bag filter. DETAILED DESCRIPTION

[0030] 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.

[0031] Unless otherwise specified, the raw materials and equipment in the embodiments of the present invention can be obtained through commercial channels or prepared or processed by known methods.

[0032] A low-energy wind turbine blade recycling method according to an embodiment of the present invention comprises the following steps:

[0033] (1) Cutting the waste wind turbine blades into blocks after removing the metal components;

[0034] (2) subjecting the waste wind turbine blades cut into blocks to a pyrolysis reaction in a pyrolysis atmosphere, wherein the pyrolysis atmosphere is a mixed gas composed of nitrogen, oxygen and ammonia, and pure glass fibers are obtained after the pyrolysis reaction;

[0035] (3) After the pyrolysis exhaust gas is cooled, it is subjected to dust removal and denitrification in a bag filter equipped with an integrated filter bag for dust removal and denitrification, and then discharged.

[0036] The present invention creatively adds ammonia to the pyrolysis atmosphere. On the one hand, it can be used as a reducing agent for subsequent low-temperature denitrification. Moreover, its addition to the pyrolysis atmosphere can also play a role of preheating and premixing, which helps to reduce the escape of denitrification ammonia. On the other hand, ammonia can dilute the combustible gas in the pyrolysis gas, prevent deflagration and reduce the release of smoke, thereby helping to improve the quality of the recovered fiber and reduce the subsequent flue gas purification cost.

[0037] In some embodiments, the volume fraction of oxygen in the pyrolysis atmosphere is between 6% and 8%. For example, the volume fraction of oxygen can be 6%, 6.5%, 6.8%, 7%, 7.5%, 8%, etc.

[0038] In some embodiments, the pyrolysis reaction is carried out in a pyrolysis furnace, the pyrolysis temperature is 400° C. to 420° C., and the pyrolysis time is 3 h to 4 h. Non-limiting examples include: the pyrolysis temperature can be 400° C., 405° C., 410° C., 413° C., 415° C., 420° C., etc., and the pyrolysis time can be 3 h, 3.2 h, 3.5 h, 3.7 h, 3.8 h, 4 h, etc.

[0039] In some embodiments, the molar ratio of the ammonia concentration in the pyrolysis furnace to the nitrogen oxide concentration in the pyrolysis tail gas is controlled between 0.8 and 1.0. For example, the molar ratio may be 0.8, 0.83, 0.85, 0.9, 0.95, 1.0, etc.

[0040] In some embodiments, before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis exhaust gas through a heat exchanger and then enters the pyrolysis furnace after preheating.

[0041] In some embodiments, the pyrolysis tail gas is cooled to between 200° C. and 220° C. after heat exchange in a heat exchanger. For non-limiting example, the temperature after cooling may be 200° C., 205° C., 210° C., 215° C., 220° C., etc.

[0042] In some embodiments, the dust removal and denitrification integrated filter bag is a low-temperature denitrification catalyst MnOx -CeO2 is loaded on a conventional polytetrafluoroethylene filter bag; wherein, MnO x It accounts for 30% of the total mass of the catalyst, CeO2 accounts for 70% of the total mass of the catalyst, and the mass fraction of the catalyst on the filter bag accounts for 63% to 65%.

[0043] In some embodiments, the integrated filter bag for dust removal and denitrification is prepared by a method comprising the following steps: manganese acetate and cerium nitrate are used as precursors of manganese oxide and cerium oxide, respectively, the amount of the precursors is converted into equimolar amounts according to the corresponding oxide content in the catalyst, perfluorosulfonic acid-polytetrafluoroethylene copolymer is used as a coupling agent, the amount of the coupling agent accounts for 30% of the mass of the impregnation solution, an impregnation solution is made with water, a conventional polytetrafluoroethylene filter bag is impregnated, and then the bag is dried at 100°C for 2 hours, and then calcined at 400°C for 2 hours to obtain the filter bag.

[0044] The embodiment of the present invention is different from the conventional impregnation method. The embodiment of the present invention uses a perfluorosulfonic acid-polytetrafluoroethylene copolymer as a coupling agent, which has good compatibility with polytetrafluoroethylene fibers and good binding properties with inorganic catalysts, thereby making the catalyst content in the prepared dust removal and denitration integrated filter bag higher, so that the filter bag prepared by the present invention has a high denitration efficiency (>90%) at low temperatures. At the same time, the preparation process of the present invention is simple and convenient for engineering implementation.

[0045] In some embodiments, the size of the waste wind turbine blades cut into blocks is ≤10 cm in length and ≤10 cm in width. It is understandable that cutting the waste wind turbine blades into small pieces facilitates their full contact with the pyrolysis atmosphere, which is helpful for pyrolysis. Non-limiting examples include: the size of the waste wind turbine blades can be cut into, for example, length×width=10 cm×10 cm, 8 cm×8 cm, 8 cm×6 cm, 6 cm×6 cm, 6 cm×4 cm, etc.

[0046] As a specific example, for example, the size of the waste wind turbine blade is length × width = 10 cm × 10 cm, the block of waste wind turbine blades is subjected to pyrolysis reaction in a pyrolysis furnace, and the pyrolysis atmosphere is continuously introduced into the pyrolysis furnace, and the total gas flow rate of the pyrolysis atmosphere can be 12L / min to 15L / min. For example, the total gas flow rate can be 12L / min, 12.5L / min, 13L / min, 14L / min, 14.5L / min, 15L / min, etc.

[0047] like Figure 1 As shown, an embodiment of the present invention further provides a low-energy consumption wind turbine blade recovery system, comprising:

[0048] The pyrolysis furnace 1 has a feed inlet, a discharge port, a pyrolysis atmosphere inlet and an exhaust gas outlet;

[0049] Heat exchanger 2, heat exchanger 2 has a hot side inlet, a hot side outlet, a cold side inlet and a cold side outlet, the hot side inlet is connected to the tail gas outlet of the pyrolysis furnace 1 through a pipeline, the cold side inlet is connected to the pyrolysis atmosphere source inlet pipe; the cold side outlet is connected to the pyrolysis atmosphere inlet of the pyrolysis furnace 1 through a pipeline;

[0050] The bag-type dust collector 3 has a plurality of filter bags arranged therein, and the filter bags are integrated filter bags for dust removal and denitrification; the bag-type dust collector 3 has a gas inlet and a gas outlet, and the gas inlet is connected to the hot side outlet of the heat exchanger 2 through a pipeline.

[0051] In some embodiments, the heat exchanger is a tubular heat exchanger.

[0052] During the working process, the block-shaped waste wind turbine blades cut into specified sizes (for example, length × width = 10cm × 10cm) are added to the pyrolysis furnace through the feed port on the pyrolysis furnace. After sufficient pyrolysis reaction in the pyrolysis atmosphere, relatively pure glass fibers are obtained and discharged through the discharge port on the pyrolysis furnace; before the pyrolysis atmosphere (mixed gas of nitrogen, oxygen and ammonia) enters the pyrolysis furnace, it first passes through the heat exchanger 2 to exchange heat with the pyrolysis tail gas, and the preheated pyrolysis atmosphere enters the pyrolysis furnace through the pyrolysis atmosphere inlet on the pyrolysis furnace 1. After the pyrolysis tail gas is discharged through the tail gas outlet, it passes through the heat exchanger 2 for heat exchange, cools down, and then passes through the bag filter 3 for dust removal and denitrification. After dust removal and denitrification, the tail gas is discharged. It can be understood that after being processed by the wind turbine blade recovery method and system of the present invention, the final tail gas meets the emission standards and can be directly discharged.

[0053] The following are non-limiting examples of the present invention.

[0054] The dust removal and denitration integrated filter bag of Examples 1 to 6 of the present invention and Comparative Examples 1 to 2 is a low-temperature denitration catalyst MnO x -CeO2 is loaded on a conventional polytetrafluoroethylene filter bag; wherein, MnO x It accounts for 30% of the total mass of the catalyst, CeO2 accounts for 70% of the total mass of the catalyst, and the mass fraction of the catalyst on the filter bag accounts for 63% to 65%. The specific preparation method is: 60g of manganese acetate and 132g of cerium nitrate are used as precursors of manganese oxide and cerium oxide respectively, 296.6g of perfluorosulfonic acid-polytetrafluoroethylene copolymer is used as a coupling agent, added into 500g of water to prepare an impregnation solution, impregnated 100g of conventional polytetrafluoroethylene filter bag, and then the impregnated filter bag is dried at 100°C for 2h, and then calcined at 400°C for 2h to obtain a dust removal and denitrification integrated filter bag.

[0055] The recycling effects of Examples 1 to 6 of the present invention and Comparative Examples 1 to 2 were evaluated by the resin residual rate of the recycled fiber (recycled fiber purity) and the strength retention rate of the recycled fiber.

[0056] The resin content in the recycled fiber (recycled fiber purity) was analyzed using a Mettler Toledo thermogravimetric analyzer. The lower the content, the more complete the resin degradation in the blades and the higher the recycled fiber purity.

[0057] The tensile strength of the fiber was measured using an LLY-06E tensile testing machine. The ratio of the tensile strength to the original fiber strength indicated the strength retention rate of the recycled fiber. The greater the retention rate, the smaller the impact of the degradation process on the recycled fiber.

[0058] In Examples 1 to 6 of the present invention and Comparative Examples 1 to 2, the denitrification efficiency was tested using a Testo 350 flue gas analyzer; and the dust removal efficiency was analyzed using a LB-70C type smoke tester.

[0059] It should be noted that the following comparative examples are not prior art and are only provided for comparison with the embodiments and are not intended to limit the present invention.

[0060] Example 1

[0061] A low-energy wind turbine blade recycling method comprises the following steps:

[0062] After removing the metal components from the waste wind turbine blades, they were cut into blocks (length × width = 10 cm × 10 cm), placed in a pyrolysis furnace with a pyrolysis atmosphere consisting of nitrogen, 6.1 (V / V)% oxygen and ammonia (gas flow rate of 14.8 L / min), and pyrolyzed at 403°C for 4 hours to obtain relatively pure glass fibers. The pyrolysis tail gas was cooled to 208°C by a heat exchanger, and was simultaneously dedusted and denitrated by a dust collector with an integrated dust removal and denitration filter bag, wherein the denitration ammonia nitrogen ratio was 0.96, and the tail gas was discharged after dust removal and denitration.

[0063] Before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis tail gas through a heat exchanger and then enters the pyrolysis furnace after preheating.

[0064] The results show that: in this embodiment 1, the fiber purity is 96.2%, the fiber strength retention rate is 93.4%, the dust removal efficiency is 99.4%, and the denitrification efficiency is 93.7%.

[0065] Example 2

[0066] A low-energy wind turbine blade recycling method comprises the following steps:

[0067] After removing the metal components from the waste wind turbine blades, they were cut into blocks (length × width = 10 cm × 10 cm), placed in a pyrolysis furnace with a pyrolysis atmosphere consisting of nitrogen, 7.7 (V / V)% oxygen and ammonia (gas flow rate of 12.2 L / min), and pyrolyzed at 418°C for 3.1 hours to obtain relatively pure glass fiber. The pyrolysis tail gas was cooled to 217°C by a heat exchanger, and was simultaneously dedusted and denitrated by a dust collector with an integrated dust removal and denitration filter bag, where the denitration ammonia nitrogen ratio was 0.88. After dust removal and denitration, the tail gas was discharged.

[0068] Before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis tail gas through a heat exchanger and then enters the pyrolysis furnace after preheating.

[0069] The results show that: in this Example 2, the fiber purity is 97.1%, the fiber strength retention rate is 92.3%, the dust removal efficiency is 99.8%, and the denitrification efficiency is 96.7%.

[0070] Example 3

[0071] A low-energy wind turbine blade recycling method comprises the following steps:

[0072] After removing the metal components from the waste wind turbine blades, they were cut into blocks (length × width = 10 cm × 10 cm), placed in a pyrolysis furnace with a pyrolysis atmosphere consisting of nitrogen, 6.5 (V / V)% oxygen and ammonia (gas flow rate of 13.2 L / min), and pyrolyzed at 410°C for 3.5 hours to obtain relatively pure glass fibers. The pyrolysis tail gas was cooled to 212°C by a heat exchanger, and was simultaneously dedusted and denitrated by a dust collector with an integrated dust removal and denitration filter bag, wherein the denitration ammonia nitrogen ratio was 0.9, and the tail gas was discharged after dust removal and denitration.

[0073] Before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis tail gas through a heat exchanger and then enters the pyrolysis furnace after preheating.

[0074] The results show that: in this embodiment 3, the fiber purity is 96.5%, the fiber strength retention rate is 92.8%, the dust removal efficiency is 99.5%, and the denitrification efficiency is 94.3%.

[0075] Example 4

[0076] A low-energy wind turbine blade recycling method comprises the following steps:

[0077] After removing the metal components from the waste wind turbine blades, they were cut into blocks (length × width = 10 cm × 10 cm), placed in a pyrolysis furnace with a pyrolysis atmosphere consisting of nitrogen, 7.1 (V / V)% oxygen and ammonia (gas flow rate of 12.8 L / min), and pyrolyzed at 406°C for 3.8 hours to obtain relatively pure glass fibers. The pyrolysis tail gas was cooled to 205°C by a heat exchanger, and was simultaneously dedusted and denitrated by a dust collector with an integrated dust removal and denitration filter bag, wherein the denitration ammonia nitrogen ratio was 0.98, and the tail gas was discharged after dust removal and denitration.

[0078] Before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis tail gas through a heat exchanger and then enters the pyrolysis furnace after preheating.

[0079] The results show that: in this embodiment 4, the fiber purity is 97%, the fiber strength retention rate is 93.2%, the dust removal efficiency is 99.6%, and the denitrification efficiency is 93.1%.

[0080] Example 5

[0081] A low-energy wind turbine blade recycling method comprises the following steps:

[0082] After removing the metal components from the waste wind turbine blades, they were cut into blocks (length × width = 8 cm × 8 cm), placed in a pyrolysis furnace with a pyrolysis atmosphere consisting of nitrogen, 8 (V / V)% oxygen and ammonia (gas flow rate of 12.4 L / min), and pyrolyzed at 420°C for 3 hours to obtain relatively pure glass fibers. The pyrolysis tail gas was cooled to 220°C by a heat exchanger, and was simultaneously dedusted and denitrated by a dust collector with an integrated dust removal and denitration filter bag, wherein the denitration ammonia nitrogen ratio was 0.9, and the tail gas was discharged after dust removal and denitration.

[0083] Before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis tail gas through a heat exchanger and then enters the pyrolysis furnace after preheating.

[0084] The results show that: in this embodiment 5, the fiber purity is 97.4%, the fiber strength retention rate is 91.8%, the dust removal efficiency is 99.7%, and the denitrification efficiency is 97.7%.

[0085] Example 6

[0086] A low-energy wind turbine blade recycling method comprises the following steps:

[0087] After removing the metal components from the waste wind turbine blades, they were cut into blocks (length × width = 6 cm × 6 cm), placed in a pyrolysis furnace with a pyrolysis atmosphere consisting of nitrogen, 7.8 (V / V)% oxygen and ammonia (gas flow rate of 12 L / min), and pyrolyzed at 415°C for 3.2 hours to obtain relatively pure glass fibers. The pyrolysis tail gas was cooled to 210°C by a heat exchanger, and was simultaneously dedusted and denitrated by a dust collector with an integrated dust removal and denitration filter bag, wherein the denitration ammonia nitrogen ratio was 0.92, and the tail gas was discharged after dust removal and denitration.

[0088] Before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis tail gas through a heat exchanger and then enters the pyrolysis furnace after preheating.

[0089] The results show that: in this Example 6, the fiber purity is 96.9%, the fiber strength retention rate is 92.5%, the dust removal efficiency is 99.7%, and the denitrification efficiency is 94%.

[0090] Comparative Example 1

[0091] A wind turbine blade recycling method comprises the following steps:

[0092] After removing the metal components from the waste wind turbine blades, they were cut into blocks (length × width = 10 cm × 10 cm), placed in a pyrolysis furnace with a pyrolysis atmosphere consisting of nitrogen and 6.1 (V / V)% oxygen (gas flow rate of 14.8 L / min), and pyrolyzed at 403°C for 4 hours to obtain relatively pure glass fibers. Ammonia was sprayed into the pyrolysis tail gas, and then the tail gas was cooled to 208°C through a heat exchanger, and then passed through a dust collector with an integrated dust removal and denitration filter bag for simultaneous dust removal and denitration, wherein the denitration ammonia nitrogen ratio was 0.96. After dust removal and denitration, the tail gas was discharged.

[0093] Before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis tail gas through a heat exchanger and then enters the pyrolysis furnace after preheating.

[0094] The results show that in comparative example 1, the fiber purity is 96.0%, the fiber strength retention rate is 90.1%, the dust removal efficiency is 99.0%, and the denitrification efficiency is 89.2%.

[0095] Comparative Example 2

[0096] A wind turbine blade recycling method comprises the following steps:

[0097] After removing the metal components from the waste wind turbine blades, they were cut into blocks (length × width = 10 cm × 10 cm), placed in a pyrolysis furnace with a pyrolysis atmosphere consisting of nitrogen and 7.7 (V / V)% oxygen (gas flow rate of 12.2 L / min), and pyrolyzed at 418°C for 3.1 hours to obtain relatively pure glass fiber. The pyrolysis tail gas was cooled to 217°C by a heat exchanger, and ammonia was sprayed into the cooled pyrolysis tail gas, and then the dust collector with integrated dust removal and denitration filter bags was used for simultaneous dust removal and denitration, wherein the denitration ammonia nitrogen ratio was 0.88. The tail gas was discharged after dust removal and denitration.

[0098] Before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis tail gas through a heat exchanger and then enters the pyrolysis furnace after preheating.

[0099] The results show that in Comparative Example 2, the fiber purity is 96.8%, the fiber strength retention rate is 89.9%, the dust removal efficiency is 99.1%, and the denitrification efficiency is 90.7%.

[0100] From the comparison between Example 1 and Comparative Example 1, and Example 2 and Comparative Example 2, it can be seen that the position of ammonia injection has a significant effect on the quality of the recovered fiber and the denitrification efficiency. There is a significant difference between the recovery fiber strength and denitrification efficiency obtained by adding ammonia to the pyrolysis furnace and adding ammonia to the pyrolysis tail gas before or after the heat exchanger. When other parameter conditions of the recovery method are the same, the fiber strength and denitrification efficiency obtained in the embodiment are significantly better than those in the comparative example, and the dust removal efficiency of the embodiment is also better than that in the comparative example. It can be seen that the embodiment of the present invention adds ammonia to the pyrolysis atmosphere, which can indeed dilute the combustible gas and prevent local deflagration from causing the loss of recovered fiber strength. At the same time, the addition of ammonia reduces the dust removal pressure, so that the dust removal efficiency is improved. When ammonia is added to the pyrolysis furnace, the preheating and premixing effects of ammonia are higher, resulting in a significant increase in the denitrification efficiency.

[0101] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0102] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0103] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", "connected" and the like should be understood in a broad sense, for example, it can be fixedly connected, detachably connected, or integrated; it can be mechanically connected, electrically connected, or able to communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0104] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0105] 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.

[0106] 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 low-energy wind turbine blade recycling method, characterized in that: The steps include: (1) Cutting the waste wind turbine blades into blocks after removing the metal components; (2) subjecting the waste wind turbine blades cut into blocks to a pyrolysis reaction in a pyrolysis atmosphere, wherein the pyrolysis atmosphere is a mixed gas composed of nitrogen, oxygen and ammonia, and pure glass fibers are obtained after the pyrolysis reaction; the pyrolysis reaction is carried out in a pyrolysis furnace, the pyrolysis temperature is 400°C to 420°C, and the pyrolysis time is 3h to 4h; (3) After the pyrolysis tail gas is cooled, it is dusted and denitrated in a bag filter with integrated filter bags for dust removal and denitration, and then discharged; In the pyrolysis atmosphere, the volume fraction of oxygen is between 6% and 8%; The molar ratio of the ammonia concentration in the pyrolysis furnace to the nitrogen oxide concentration in the pyrolysis tail gas is controlled between 0.8 and 1.

0.

2. A low-energy wind turbine blade recycling method according to claim 1, characterized in that: Before the pyrolysis atmosphere enters the pyrolysis furnace, it first exchanges heat with the pyrolysis tail gas through a heat exchanger and then enters the pyrolysis furnace after being preheated.

3. A low-energy wind turbine blade recycling method according to claim 2, characterized in that: The pyrolysis tail gas is cooled to between 200°C and 220°C after heat exchange in a heat exchanger.

4. A low-energy wind turbine blade recycling method according to claim 1, characterized in that: The dust removal and denitration integrated filter bag is a low-temperature denitration catalyst MnO x -CeO2 is loaded on a conventional polytetrafluoroethylene filter bag; Among them, MnO x It accounts for 30% of the total mass of the catalyst, CeO2 accounts for 70% of the total mass of the catalyst, and the mass fraction of the catalyst on the filter bag accounts for 63%~65%.

5. A low-energy wind turbine blade recycling method according to claim 4, characterized in that: The integrated filter bag for dust removal and denitrification is prepared by a method comprising the following steps: manganese acetate and cerium nitrate are used as precursors of manganese oxide and cerium oxide respectively, equimolar conversion of metal elements is performed according to the corresponding oxide content in the catalyst, the corresponding amount of precursor is calculated, perfluorosulfonic acid-polytetrafluoroethylene copolymer is used as a coupling agent, the amount of the coupling agent accounts for 30% of the mass of the impregnation solution, and an impregnation solution is prepared with water, a conventional polytetrafluoroethylene filter bag is impregnated, and then the bag is dried at 100°C for 2h, and then calcined at 400°C for 2h to prepare the integrated filter bag for dust removal and denitrification.

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