EPDM (Ethylene-Propylene-Diene Monomer) regenerated rubber containing waste wind power blade cracking product and preparation method of EPDM regenerated rubber

Abstract

The invention belongs to the technical field of regenerated rubber, and discloses EPDM regenerated rubber containing waste wind power blade cracking products and a preparation method thereof.The method comprises the following steps that waste wind power blades are crushed into particles, impurities are removed, the particles are fed into a first screw extruder, a moderate cracking reaction is completed through shearing at the temperature of 300-600 DEG C, and a second screw extruder is obtained; and feeding the cracking product into a second screw extruder, carrying out desulfurization regeneration on the cracking product and preheated waste ethylene-propylene-diene monomer rubber powder to obtain a desulfurized rubber material, and refining and filtering the desulfurized rubber material to obtain regenerated rubber. According to the method, after being properly treated, the resin and the fiber in the wind power blade participate in the waste rubber regeneration process and play a certain reinforcing effect, synergistic high-valued regeneration of the fiber and the resin is achieved, the problem of disposal of the waste fan blade is solved, the tensile strength of the regenerated rubber is improved, and the method is energy-saving and environment-friendly.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of reclaimed rubber, and particularly relates to a ternary ethylene-propylene reclaimed rubber containing waste wind blade pyrolysis products and a preparation method thereof. BACKGROUND

[0002] Wind power generation is one of the core components of new energy power generation. As of the end of 2021, China's wind power grid-connected installed capacity has reached 30015 MW, accounting for about 13% of the total installed capacity of the country, and its power generation accounts for about 7.5% of the total social electricity consumption. The design life of a wind turbine is generally 20 to 25 years. China began to promote the development of the wind power industry on a large scale around 2000. It is estimated in the industry that in 2025, the domestic wind power industry will usher in the first wave of large-scale wind turbine “retirement”, with a retirement scale exceeding 1.2 GW. At present, there is no comprehensive recycling technology and processing standard, and there is also no law and regulation and industry system for recycling of bulk industrial solid waste, so the disposal of retired blades has become one of the current difficulties.

[0003] The wind turbine blade, as a key component of the unit, is mainly made of composite materials, including thermosetting / thermoplastic resins, fiber materials such as glass fiber and carbon fiber, filling materials such as balsa wood and foam, and auxiliary materials such as adhesives. Among these materials, the fiber materials have high recycling value, and other materials also have certain resource potential, but due to the structure of the blade and the characteristics of the materials, it is difficult to effectively separate and recycle each component.

[0004] The traditional disposal method of waste wind blades mainly includes stacking, landfilling and incineration, which does not meet the environmental protection requirements and cannot realize resource utilization, and has been gradually eliminated by the market. In recent years, the industry has proposed various resource utilization schemes, mainly including: (1) pyrolysis method: promoting the thermal cracking of organic components by high temperature to separate glass fibers, but high temperature can easily cause glass fibers to fuse and adhere, and carbon fibers to oxidize, making it difficult to guarantee the quality and yield of recycled fibers; (2) chemical degradation method: using organic solvents to dissolve resins to separate fibers, which can better preserve the performance of fibers, but the amount of organic solvents used is large, the subsequent separation process is complex, and it may cause secondary pollution; (3) cement kiln co-processing method: sending the crushed blades into a cement kiln, where the combustible components can replace fossil fuels as fuel, and the incombustible components rich in silicon can be used as cement raw materials, achieving the dual goals of low cost and resource utilization of waste blades, but this method destroys the most valuable fiber materials in the wind turbine blades, and the overall economic value of the process is low, so it needs to be improved.

[0005] In addition, the above-mentioned various resource utilization schemes also have a common core defect. The resource utilization of the resin materials which account for a considerable proportion in the blades is seriously insufficient, only the recycling of fibers is concerned, and the resins are treated as waste or low-value fuel.

[0006] Therefore, there is an urgent need to provide a new method for realizing the synergistic high-value regeneration of fibers and resins, which not only solves the disposal problem of waste wind turbine blades, fully excavates the utilization value of components such as fibers and resins, but also improves the tensile strength of the regenerated rubber, saves energy and protects the environment. SUMMARY

[0007] The present application aims at the deficiencies in the background art and provides a ternary ethylene-propylene regenerated rubber containing waste wind turbine blade pyrolysis products, and a preparation method thereof. The resins and fibers in the wind turbine blades are properly treated and participate in the waste rubber regeneration process and play a certain reinforcing effect.

[0008] To achieve the above-mentioned purposes, the technical solution of the present application is as follows: A preparation method of ternary ethylene-propylene regenerated rubber containing waste wind turbine blade pyrolysis products, comprising the following steps: S1, crushing the waste wind turbine blade into particles with a particle size of less than 5 mm, and removing impurities other than fibers and resins; S2, feeding the particles into a first screw extruder to complete a moderate pyrolysis reaction under the action of shearing at 300-600 DEG C to obtain a pyrolysis product; S3, feeding the pyrolysis product into a second screw extruder to perform desulfurization regeneration with preheated waste ternary ethylene-propylene rubber powder to obtain a desulfurized rubber material; S4, obtaining the regenerated rubber after refining and filtering the desulfurized rubber material.

[0009] Preferably, the mass fraction ratio of the pyrolysis product to the waste ternary ethylene-propylene rubber powder is 1-5:100.

[0010] Preferably, the mass content of the fibers in the waste wind turbine blade is 60%-70%, and the mass content of the resins is 30%-40%.

[0011] Preferably, the fiber length-diameter ratio in the pyrolysis product is 100-200:1, the length is 0.1-0.5 mm, and the molecular weight of the epoxy resin is 2000-5000.

[0012] Preferably, the waste ternary ethylene-propylene rubber powder is one or a mixture of two obtained from waste ternary ethylene-propylene waste sealing strips or cables, and the particle size is less than 5 mm, which is increased from room temperature to 100-150 DEG C within 0.5-2 min.

[0013] Preferably, the first screw extruder is a co-rotating twin-screw extruder or a triple-screw extruder, and the length-diameter ratio thereof is 32-52:1, and the rotation speed is 100-300 rpm.

[0014] Preferably, the second screw extruder is a pin-type single-screw extruder or a co-rotating twin-screw extruder or a triple-screw extruder, and the length-diameter ratio thereof is 32-48:1.

[0015] Preferably, the first screw extruder or the second screw extruder each comprises a mixing and kneading section, a reaction section and a cooling section, the temperature of each section is 200-300℃, 300-360℃ and 90-200℃ respectively, and the reaction time is 1-4min.

[0016] Preferably, the refining in step S4 adopts a double-roll refiner, and the Mooney viscosity of the reclaimed rubber after refining is 20-50.

[0017] Compared with the prior art, the present application has the following advantages: (1) The present application proposes the process requirements of the fiber and resin regeneration process in the wind blade by combining the demand for the reinforcing performance of the reclaimed rubber, and avoids the loss of mechanical properties of the fiber material due to high-temperature oxidation or melting through the precise synergistic control of the temperature field and the shear field, breaks the interface bonding of the blade composite material through gradient shear, provides a breakthrough solution for this problem, and fully excavates the utilization value of the fiber, resin and other components; (2) The moderate cracking of the present application only breaks part of the chemical bonds, the molecular chain of the epoxy resin is moderately broken, and the addition of the fiber and the resin not only can significantly improve the tensile strength of the reclaimed rubber, but also can replace part of the virgin reinforcing material, realizes the closed-loop circulation of the waste wind blade resources, reduces the raw material cost of the rubber industry, relieves the environmental protection pressure, and helps the collaborative green development of new energy and the rubber industry; (3) The present application takes advantage of the flexible and variable characteristics of the geometric arrangement of the screw extruder, forms multiple changes in the flow direction and flow rate, and the designed screw extruder has the characteristics of strong shear, full melting and uniform shear of the wind blade particles; the screw used for the desulfurization process has the characteristics of weak shear and strong mixing effect, can make the waste rubber powder and the wind blade cracking products fully penetrate and preheat; not only the desulfurization of the inside and outside of the single rubber powder particle is relatively uniform, but also the desulfurization degree of each rubber powder particle is basically the same, greatly increasing the stability and uniformity of the product, and greatly improving the product quality. DETAILED DESCRIPTION

[0018] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific embodiments, features and effects according to the present application are described in detail as follows.

[0019] Example 1 The waste wind turbine blade with the mass content of fiber of 63% and the mass content of resin of 35% was crushed and impurities were removed to obtain wind turbine blade particles with a particle size of less than 3 mm. The wind turbine blade particles were fed into a co-rotating twin-screw extruder with a length-diameter ratio of 52:1, and a moderate pyrolysis reaction was completed under the conditions of a temperature of 340°C and a rotating speed of 200 rpm to obtain a pyrolysis product. The length-diameter ratio of the treated fiber was about 113:1, the length was about 0.4 mm, and the molecular weight of the epoxy resin was 2257. The waste EPDM seal strip rubber powder with a particle size of less than 5 mm was heated from room temperature to 110°C in 0.5 min by using a high-speed mixer, and was added into a twin-screw extruder with a length-diameter ratio of 36:1, the temperature of the mixing and mixing section of the extruder was 240°C, the temperature of the reaction section was 360°C, the time was 4 min, and the temperature of the cooling section was 150°C. After refining by a double-roll refiner, a regenerated rubber with a Mooney viscosity of 40 was obtained.

[0020] Example 2 The waste wind turbine blade with the mass content of fiber of 66% and the mass content of resin of 33% was crushed and impurities were removed to obtain wind turbine blade particles with a particle size of less than 2 mm. The wind turbine blade particles were fed into a co-rotating twin-screw extruder with a length-diameter ratio of 48:1, and a moderate pyrolysis reaction was completed under the conditions of a temperature of 400°C and a rotating speed of 150 rpm to obtain a pyrolysis product. The length-diameter ratio of the treated fiber was about 150:1, the length was about 0.2 mm, and the molecular weight of the epoxy resin was 4289. The waste EPDM cable rubber powder with a particle size of less than 4 mm was heated from room temperature to 140°C in 1 min by using a double-helix conveyor, and was added into a twin-screw extruder with a length-diameter ratio of 40:1, the temperature of the mixing and mixing section of the extruder was 220°C, the temperature of the reaction section was 340°C, the temperature of the cooling section was 150°C, and the reaction time was 3 min. After refining by a double-roll refiner, a regenerated rubber with a Mooney viscosity of 30 was obtained.

[0021] Comparative Example 1 The waste EPDM seal strip rubber powder with a particle size of less than 5 mm was heated from room temperature to 110°C in 0.5 min by using a high-speed mixer, and was added into a twin-screw extruder with a length-diameter ratio of 36:1, the temperature of the mixing and mixing section of the extruder was 240°C, the temperature of the reaction section was 360°C, the time was 4 min, and the temperature of the cooling section was 150°C. After refining by a double-roll refiner, a regenerated rubber with a Mooney viscosity of 42 was obtained.

[0022] Comparative Example 2 The waste cable rubber powder with a particle size less than 4 mm is added into a double-screw extruder with a length-diameter ratio of 40:1 by using a double-screw conveyor to increase the temperature from room temperature to 140 DEG C within 1 minute, the temperature of the mixing and kneading section of the extruder is 220 DEG C, the temperature of the reaction section is 340 DEG C, the temperature of the cooling section is 150 DEG C, and the reaction time is 3 minutes; and the regenerated rubber with a Mooney viscosity of 33 is obtained after refining by a double-roll refiner.

[0023] The test data of the regenerated rubbers prepared in the above example 1, example 2, comparative example 1 and comparative example 2 are shown in the following table: According to the comparison between example 1 and comparative example 1, and the comparison between example 2 and comparative example 2 in the above table, it can be seen that in terms of tensile strength, the waste wind blade pyrolysis product treated by the present application can be used as an effective reinforcing material, and is well combined with the rubber matrix, thereby improving the mechanical properties of the material and effectively improving the regeneration value of various quality rubber powders; in terms of elongation at break, the pyrolysis product added in the present application enables the regenerated rubber to deform more when subjected to external force without being damaged, and the comprehensive performance is more balanced; in terms of Mooney viscosity, the present application effectively improves the flowability of the rubber compound, making it easier to carry out subsequent mixing, extrusion and other processes, which is crucial for industrial production.

[0024] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, without departing from the technical solution of the present application. Any modification, change and modification of the above embodiments according to the technical essence of the present application, as long as it does not deviate from the technical solution of the present application, still belongs to the scope of the technical solution of the present application.

Claims

1. A method for preparing EPDM recycled rubber containing pyrolysis products of waste wind turbine blades, characterized in that, Includes the following steps: S1, crush the waste blower blades into particles with a diameter of less than 5mm to remove impurities; S2, the particles are fed into the first screw extruder and undergo a moderate pyrolysis reaction under shearing at 300-600℃ to obtain pyrolysis products; S3, the pyrolysis products are fed into the second screw extruder and desulfurized and regenerated with preheated waste EPDM rubber powder to obtain desulfurized rubber material; S4, desulfurized rubber is refined and filtered to obtain recycled rubber.

2. The method for preparing EPDM recycled rubber containing waste wind turbine blade pyrolysis products according to claim 1, characterized in that: The mass ratio of the pyrolysis products to the waste EPDM rubber powder is 1-5:

100.

3. The method for preparing EPDM recycled rubber containing waste wind turbine blade pyrolysis products according to claim 1, characterized in that: The waste wind turbine blades contain 60%-70% fiber and 30%-40% resin by mass.

4. The method for preparing EPDM recycled rubber containing waste wind turbine blade pyrolysis products according to claim 1, characterized in that: The fiber aspect ratio in the pyrolysis products is 100-200:1, the length is 0.1-0.5 mm, and the molecular weight of the epoxy resin is 2000-5000.

5. The method for preparing EPDM recycled rubber containing waste wind turbine blade pyrolysis products according to claim 1, characterized in that: The waste EPDM rubber powder is one or a mixture of two waste EPDM sealing strips or cables, with a particle size of less than 5 mm, and can be heated from room temperature to 100-150°C within 0.5-2 minutes.

6. The method for preparing EPDM recycled rubber containing waste wind turbine blade pyrolysis products according to claim 1, characterized in that: The first screw extruder is a co-rotating twin-screw extruder or a three-screw extruder, with a length-to-diameter ratio of 32-52:1 and a rotational speed of 100-300 rpm.

7. The method for preparing EPDM recycled rubber containing waste wind turbine blade pyrolysis products according to claim 1, characterized in that: The second screw extruder is a pin-type single-screw extruder, a co-rotating twin-screw extruder, or a three-screw extruder, and its length-to-diameter ratio is 32-48:

1.

8. The method for preparing EPDM recycled rubber containing waste wind turbine blade pyrolysis products according to claim 1, characterized in that: Both the first screw extruder and the second screw extruder include a mixing and compounding section, a reaction section and a cooling section, with temperatures of 200-300℃, 300-360℃ and 90-200℃ respectively, and a reaction time of 1-4 min.

9. The method for preparing EPDM recycled rubber containing waste wind turbine blade pyrolysis products according to claim 1, characterized in that: In step S4, a two-roll mill is used for refining, and the Mooney viscosity of the reclaimed rubber after refining is 20-50.

10. The EPDM recycled rubber containing waste wind turbine blade pyrolysis products according to claim 1, characterized in that: The EPDM reclaimed rubber containing waste wind turbine blade pyrolysis products is prepared according to any one of claims 1-9.

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