Recycling system of fiber blend product

Abstract

A recycling system of fiber blend product includes a chemical separation device and a physical separation device. The chemical separation device is configured to carry out a hydrothermal degradation reaction on a fiber blend product, in which first fibers in the fiber blend product does not undergo any chemical changes, and second fibers in the fiber blend product degrades. The physical separation device includes a water infiltration device and a pressing device. The water infiltration device is operatively connected to the chemical separation device, and is configured to wet the fiber blend product that has undergone the hydrothermal degradation reaction with water. The pressing device is operatively connected to the water infiltration device, and is configured to press the wetted fiber blend product, such that water inside the wetted fiber blend product penetrates outward and brings out degradation products of the second fiber under the action of mechanical force.

Description

Technical Field

[0001] The present invention relates to a recycling system for fiber products, and in particular to a recycling system for blended fiber products, such as finished products made by blending polyester fiber with natural fibers such as cotton and wool. Prior Art

[0002] Polyester / cotton blended fabrics are widely used in clothing, home textiles and other fields because they combine the durability of polyester with the comfort of cotton. However, the amount of waste of these products is huge, and only a small part of them enters the recycling system.

[0003] Furthermore, the complex composition and structure of polyester / cotton blended fabrics make separation and processing expensive. Furthermore, the significant differences in the physical and chemical properties of polyester and cotton fibers make it difficult to physically separate cotton from polyester fibers using a single treatment method. Instead, a combination of different treatments is required, resulting in a complex separation process. Therefore, TWI845823B discloses sequentially subjecting mixed fiber textile materials to mechanical decomposition, acid treatment, and alkaline treatment. Mechanical decomposition is used to break down the textile structure within the material; acid treatment is used to adjust the degree of polymerization of cellulose and dissolve and remove acid-soluble impurities; and alkaline treatment is used to remove non-cellulose components and further adjust the properties of the cellulose.

[0004] WO2019047174A1 discloses a method for breaking a polyester / cotton blended fabric into fragments and dispersing them in an aqueous solution of an organic acid catalyst to form a mixed system with a solid-to-liquid ratio of 1:30-200. The mixed system is then heated to 110-180°C. This method consumes a large amount of liquid, and the recovered polyester fiber still contains a small amount of cotton shreds, resulting in poor purity. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a recycling system for blended fiber products in response to the shortcomings of the existing technology, which can separate polyester fibers and natural fibers such as cotton and wool in blended fiber products for high-purity recycling.

[0006] To address the aforementioned technical issues, one of the technical solutions employed by the present invention is to provide a recycling system for blended fiber products, comprising a chemical separation device and a physical separation device. The chemical separation device is configured to subject a blended fiber product to a hydrothermal degradation reaction; the blended fiber product comprises a first fiber and a second fiber different from the first fiber, and during the hydrothermal degradation reaction, the first fiber undergoes no chemical change while the second fiber degrades. The physical separation device comprises a water impregnation device and an extrusion device; the water impregnation device is operably connected to the chemical separation device and configured to impregnate the blended fiber product after the hydrothermal degradation reaction with water; the extrusion device is operably connected to the water impregnation device and configured to squeeze the water-impregnated blended fiber product, causing the water within the blended fiber product to permeate outward under the action of mechanical force and remove degradation products of the second fiber.

[0007] In a feasible or preferred embodiment of the present invention, the physical separation device includes a separator, which is operably connected to the extrusion device and is configured to retain the extruded blended fiber product and allow water and degradation products of the second fiber to pass through.

[0008] In a feasible or preferred embodiment of the present invention, the physical separation device includes a conveyor. The conveyor is arranged between the water infiltration device and the separator to provide a conveying path from the separator back to the water infiltration device.

[0009] In a feasible or preferred embodiment of the present invention, the water soaking device is connected to the separator through a filter to reuse the wastewater from the separator. In addition, the filter is configured to filter out degradation products of the second fiber from the wastewater from the separator.

[0010] In a feasible or preferred embodiment of the present invention, the water-soaking device includes a sprinkler and a feeder, with the sprinkler positioned above the feeder. Furthermore, the sprinkler is configured to spray water onto the blended fiber product undergoing the hydrothermal degradation reaction, and the feeder is configured to supply the water-soaked blended fiber product to the extrusion device for extrusion.

[0011] In a feasible or preferred embodiment of the present invention, the extrusion device includes at least one extrusion roller assembly. The at least one extrusion roller assembly includes two rollers disposed opposite to each other, and the two rollers can be driven to rotate toward each other to press the blended fiber product soaked in water.

[0012] In a feasible or preferred embodiment of the present invention, the at least one squeezing roller group includes a first squeezing roller group and a second squeezing roller group arranged in sequence.

[0013] In a feasible or preferred embodiment of the present invention, the chemical separation device includes a reactor configured to allow a catalyst aqueous solution to contact the blended fiber product to cause the hydrothermal degradation reaction.

[0014] In a feasible or preferred embodiment of the present invention, the chemical separation equipment includes a liquid storage tank for storing the aqueous catalyst solution. Furthermore, a spray device is provided within the reactor, and the spray device is connected to the liquid storage tank via a circulation pipeline.

[0015] In a feasible or preferred embodiment of the present invention, the circulation pipeline is configured to allow the aqueous catalyst solution to circulate between the reactor and the liquid storage tank and be sprayed from the spray device to repeatedly contact the blended fiber product. Furthermore, the frequency of contact between the aqueous catalyst solution and the blended fiber product is 3 to 4 times per minute, and the solid-to-liquid ratio of the aqueous catalyst solution to the blended fiber product is 1:5-10.

[0016] In general, the blended fiber product recovery system provided by the present invention, by virtue of "a chemical separation device configured to subject a blended fiber product to a hydrothermal degradation reaction," "a water impregnation device configured to impregnate the blended fiber product that has undergone the hydrothermal degradation reaction with water," and "an extrusion device configured to extrude the water-impregnated blended fiber product," can easily physically separate cotton fibers from polyester fibers in the blended fiber product, ensuring excellent separation efficiency even under low solid-liquid ratio conditions. Furthermore, the recovered polyester fibers can achieve a purity greater than 98%, while the recovered cotton fibers can achieve a purity greater than 99%.

[0017] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Simple diagram description

[0018] FIG1 is a schematic block diagram of a recycling system for blended fiber products according to the present invention.

[0019] FIG. 2 is another block diagram of the blended fiber product recycling system of the present invention.

[0020] FIG3 is a partial structural diagram of the physical separation equipment of the blended fiber product recovery system of the present invention.

[0021] FIG4 is a schematic structural diagram of the chemical separation equipment of the blended fiber product recovery system of the present invention.

[0022] FIG5 is a flow chart of the method for recycling blended fiber products of the present invention. Implementation Method

[0023] The following describes, through specific embodiments, the implementation of the "Blended Fiber Product Recycling System" disclosed herein. Those skilled in the art will understand the advantages and benefits of the present invention from the disclosure herein. The present invention may be implemented or applied through various other specific embodiments, and the details herein may be modified and altered based on different perspectives and applications without departing from the scope of the present invention. Furthermore, the drawings herein are for illustrative purposes only and are not intended to be drawn to actual size. This is to be noted in advance. The following embodiments further illustrate the relevant technical aspects of the present invention, but the disclosure herein is not intended to limit the scope of protection of the present invention.

[0024] It should be understood that while terms such as "first," "second," and "third" may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. Furthermore, the term "or" as used herein may include any one or more combinations of the associated listed items, as appropriate.

[0025] [First embodiment]

[0026] Referring to Figure 1, a first embodiment of the present invention provides a blended fiber product recycling system Z, comprising a chemical separation device 1 and a physical separation device 2. The chemical separation device 1 is configured to subject the blended fiber product to be processed to a hydrothermal degradation reaction. The blended fiber product may include a first fiber and a second fiber different from the first fiber. During the hydrothermal degradation reaction, the first fiber does not undergo chemical changes while the second fiber degrades. The physical separation device 2 is operably connected to the chemical separation device 1 and is configured to squeeze the blended fiber product after the hydrothermal degradation reaction under the action of water. This mechanical force allows the water to penetrate the blended fiber product, thereby removing the degradation products of the second fiber. This allows the different fiber components to be separated from the blended fiber product for high-purity recovery. Optionally, the blended fiber product to be processed may be divided into several fragments (small pieces) before the hydrothermal degradation reaction.

[0027] In this embodiment, the first fiber of the blended fiber product is polyester fiber, which does not degrade during the hydrothermal degradation reaction; the second fiber of the blended fiber product is cotton fiber, which degrades during the hydrothermal degradation reaction and separates from the polyester fiber in the form of degradation products. Polyester fibers may include polyethylene terephthalate (PET) fibers, polypropylene terephthalate (PPT) fibers, polybutylene terephthalate (PBT) fibers, poly(1,4-cyclohexanedimethylene terephthalate) (PCT) fibers, and / or polyethylene naphthalate (PEN) fibers.

[0028] However, the above is only one possible embodiment and is not intended to limit the present invention. In some embodiments, the first fiber of the blended fiber product is still polyester fiber, but the second fiber can be wool fiber or nylon fiber.

[0029] As shown in FIG4 , the chemical separation apparatus 1 primarily comprises a reactor 11, within which a sealed environment of high temperature and high pressure is formed. Specifically, the reactor 11 is configured to allow a catalyst aqueous solution to contact the blended fiber product to induce a hydrothermal degradation reaction. This contacting may involve immersing the blended fiber product in the catalyst aqueous solution or circulating the catalyst aqueous solution through the blended fiber product.

[0030] In this embodiment, the hydrothermal degradation reaction can be carried out at a temperature of 130°C to 160°C. The aqueous catalyst solution comprises at least one catalyst and water. Based on 100 wt% of the total aqueous catalyst solution, the catalyst content can be 0.1 wt% to 10 wt%, preferably 3 wt% to 5 wt%. Suitable catalysts for use in the present invention can be organic acids, organic anhydrides, Lewis acids, or any combination thereof. It should be noted that increasing the catalyst content can accelerate the degradation of the second fiber in the blended fiber product, thereby shortening the reaction time, but this also increases costs.

[0031] Specific examples of organic acids include: methanesulfonic acid, oxalic acid, tartaric acid, citric acid, malic acid, formic acid, and acetic acid; as a catalyst in the catalyst aqueous solution, the organic acid is preferably oxalic acid.

[0032] Specific examples of organic acid anhydrides include acetic anhydride, propionic anhydride, butyric anhydride, valeric anhydride, lauric anhydride, palmitic anhydride, stearic anhydride, malonic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, acrylic anhydride, cinnamic anhydride, phthalic anhydride, acetic benzoic anhydride, amino acid anhydrides, and derivatives thereof; as the catalyst in the catalyst aqueous solution, the organic acid anhydride is preferably acetic anhydride.

[0033] Specific examples of Lewis acids include boron trichloride, zinc chloride, ferric chloride, copper chloride, nickel nitrate, cobalt nitrate and zinc tetrafluoroborate; as a catalyst for the catalyst aqueous solution, the Lewis acid is preferably at least one of zinc chloride and ferric chloride.

[0034] In practical applications, the chemical separation apparatus 1 may further include a liquid reservoir 12 to store the aqueous catalyst solution, and the liquid reservoir 12 is configured to supply the aqueous catalyst solution to the reactor 11. In an embodiment in which the aqueous catalyst solution is circulated through the blended fiber product, a spray device 111 may be provided within the reactor 11, and the spray device 111 is connected to the liquid reservoir 12 via a circulation pipeline 13, wherein a circulation pump 14 is mounted on the spray device 111. Accordingly, the aqueous catalyst solution can repeatedly contact the blended fiber product in a circulatory reflux manner. Specifically, the aqueous catalyst solution, under the action of the circulation pump 14, travels back and forth between the reactor 11 and the liquid reservoir 12 via the circulation pipeline 13, and is sprayed out of the spray device 111 to repeatedly contact the blended fiber product.

[0035] Furthermore, the aqueous catalyst solution is transported from the bottom of the reactor 11 through the upstream side 131 of the circulation line 13 by the circulation pump 14 to the liquid storage tank 12. Furthermore, the aqueous catalyst solution in the liquid storage tank 12 is transported by the circulation pump 14 through the downstream side 132 of the circulation line 13 to the spray device 111 for recycling. The entire process can be fully automated. During the hydrothermal degradation reaction under this operation, the aqueous catalyst solution contacts the blended fiber product three to four times per minute, and the solid-to-liquid ratio of the aqueous catalyst solution to the blended fiber product is 1:5-10. Therefore, the chemical separation device 1 can perform the reaction at a lower solid-to-liquid ratio, significantly reducing the amount of aqueous catalyst solution used and lowering costs. Furthermore, the chemical separation device 1 does not use any solvents during the hydrothermal degradation reaction, thus posing no environmental risks.

[0036] As shown in FIG2 , the physical separation apparatus 2 primarily comprises a water impregnation device 21 and an extrusion device 22. The water impregnation device 21 is operably connected to the chemical separation apparatus 1 and is configured to impregnate the blended fiber product that has undergone the hydrothermal degradation reaction with water. The extrusion device 22 is operably connected to the water impregnation device 21 and is configured to squeeze the water-impregnated blended fiber product, causing the water within the blended fiber product to permeate outward under the action of mechanical force, removing degradation products of the second fiber.

[0037] As further shown in FIG3 , the water-soaking device 21 may include a sprinkler 211 and a feeder 212. The sprinkler 211 is positioned above the feeder 212 and is configured to spray water onto the blended fiber product undergoing the hydrothermal degradation reaction. The feeder 212 is configured to supply the water-soaked blended fiber product to the extrusion device 22; the feeder 212 may be a hopper-type feeder, but is not limited thereto. Furthermore, the extrusion device 22 may include at least one extrusion roller assembly 221, which operates by rolling and squeezing the blended fiber product using two opposing rollers to squeeze out the water, while simultaneously removing degradation products of the second fiber.

[0038] Furthermore, the squeezing roller assembly 221 may include two rollers disposed opposite each other, each driven to rotate in opposite directions. When the water-soaked blended fiber product falls between the two rollers through the feeder 212, it is squeezed by the two rollers. Optionally, the squeezing device 22 may include multiple squeezing roller assemblies to increase squeezing efficiency. For example, the squeezing device 22 may include an upper row of squeezing roller assemblies 221 and a lower row of squeezing roller assemblies 221 to perform a secondary squeezing of the water-soaked blended fiber product, thereby squeezing out more degradation products of the second fiber.

[0039] Referring again to FIG. 2 , in actual use, the physical separation apparatus 2 may further include a separator 23 to facilitate recovery of the first fiber from the blended fiber product. Separator 23 is operably connected to the extrusion device 22 and is configured to retain the extruded blended fiber product while allowing water and degradation products of the second fiber to pass through. Separator 23 may be, but is not limited to, a screen-type separator. Furthermore, the physical separation apparatus 2 may further include a filter 24 configured to filter out degradation products of the second fiber from the wastewater from the separator 23, thereby facilitating reuse of the wastewater from the separator 23.

[0040] To improve the operability and practicality of the system, the physical separation device 2 may further include a conveyor 25. The conveyor 25 is positioned between the water-impregnating device 21 and the sorter 23 to provide a conveying path (cloth circulation path) from the sorter 23 back to the water-impregnating device 21. The conveyor 25 may include, but is not limited to, one or more belt conveyors. Therefore, the blended fiber product that has undergone the hydrothermal degradation reaction can be repeatedly water-impregnated and extruded at least once to squeeze out more degradation products of the second fiber.

[0041] [Second embodiment]

[0042] Referring to Figure 5 , a second embodiment of the present invention provides a method for recycling blended fiber products, comprising: step S1, subjecting a blended fiber product to a hydrothermal degradation reaction; step S2, soaking the hydrothermally degraded blended fiber product with water; and step S3, extruding the water-soaked blended fiber product. The blended fiber product recycling method of the present invention can be implemented by the system described in the first embodiment to separate and recycle different fiber components (e.g., polyester and cotton fibers) within the blended fiber product.

[0043] In step S1, a catalyst aqueous solution may be brought into contact with the blended fiber product to cause a hydrothermal degradation reaction. This contact may include immersing the blended fiber product in the catalyst aqueous solution or circulating the catalyst aqueous solution through the blended fiber product. During the hydrothermal degradation reaction, the first fiber of the blended fiber product does not degrade, while the second fiber degrades and separates from the first fiber in the form of degradation products.

[0044] In the example where the first fiber in the blended fiber product is polyester fiber and the second fiber is cotton fiber, the hydrothermal degradation reaction can be carried out at a temperature of 130°C to 160°C. Furthermore, in the example where the catalyst aqueous solution is circulated through the blended fiber product, the catalyst aqueous solution repeatedly contacts the blended fiber product in a cyclic reflux manner; the frequency of contact between the catalyst aqueous solution and the blended fiber product is 3 to 4 times per minute, and the solid-to-liquid ratio of the catalyst aqueous solution to the blended fiber product is 1:5-10.

[0045] In step S2, water may be sprayed onto the blended fiber product that has undergone the hydrothermal degradation reaction to allow it to absorb water and soak. In step S3, the blended fiber product may be squeezed out of the water by rolling and extruding the blended fiber product, while also removing the degradation products of the second fiber.

[0046] The relevant technical details mentioned in the first embodiment are still valid in this embodiment, and will not be repeated here to reduce repetition. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the first embodiment.

[0047] [Beneficial Effects of Embodiments]

[0048] The blended fiber product recovery system provided by the present invention, by virtue of "a chemical separation device configured to subject a blended fiber product to a hydrothermal degradation reaction," "a water impregnation device of the physical separation device configured to impregnate the blended fiber product that has undergone the hydrothermal degradation reaction with water," and "an extrusion device of the physical separation device configured to extrude the water-impregnated blended fiber product," can easily physically separate cotton fibers from polyester fibers in the blended fiber product, ensuring excellent separation efficiency even under low solid-liquid ratio conditions. Furthermore, the recovered polyester fibers can achieve a purity greater than 98%, while the recovered cotton fibers can achieve a purity greater than 99%.

[0049] In the comparative example where the PET / cotton blended fiber product was treated only with a chemical separation device at a solid-to-liquid ratio of 1:10, the recovered PET fiber purity was 85.3%, and the recovered cotton fiber purity was 98.5%. In comparison, in Example 1, where the PET / cotton blended fiber product was treated sequentially with a chemical separation device at a solid-to-liquid ratio of 1:5 and then with a physical separation device, the recovered PET fiber purity was 98.2%, and the recovered cotton fiber purity was 99.5%. In Example 2, where the PET / cotton blended fiber product was treated sequentially with a chemical separation device at a solid-to-liquid ratio of 1:8 and then with a physical separation device, the recovered PET fiber purity was 98.6%, and the recovered cotton fiber purity was 99.8%. In Example 3, where the PET / cotton blended fiber product was treated sequentially with a chemical separation device at a solid-to-liquid ratio of 1:10 and then with a physical separation device, the recovered PET fiber purity was 98.8%, and the recovered cotton fiber purity was 99.8%.

[0050] Furthermore, the recycling system for blended fiber products of the present invention can realize the recycling of fiber resources, has significant economic benefits, and meets the requirements of industrial production.

[0051] The contents disclosed above are only preferred feasible embodiments of the present invention and do not limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention's description and drawings are included in the scope of the patent application of the present invention.

[0052] Z: Recycling system for blended fiber products 1:Chemical separation equipment 11: Reactor 111: Spraying device 12: Liquid reservoir 13: Circulation pipeline 131: Upstream side 132: Downstream side 14: Circulation pump 2: Physical separation equipment 21: Water infiltration device 211:Sprinkler 212: Feeder 22: Extrusion device 221: Extrusion roller set 221A: First extrusion roller group 221B: Second extrusion roller group 23: Sorter 24:Filter 25:Conveyor

Claims

1. A recycling system for blended fiber products, comprising: A chemical separation device, configured to subject a blended fiber product to a hydrothermal degradation reaction, wherein the blended fiber product comprises a first fiber and a second fiber different from the first fiber, and in the hydrothermal degradation reaction, the first fiber does not undergo chemical changes while the second fiber degrades; and a physical separation device, comprising a water infiltration device and an extrusion device; wherein the water infiltration device is operably connected to the chemical separation device and is configured to infiltrate the blended fiber product that has undergone the hydrothermal degradation reaction with water; wherein the extrusion device is operably connected to the water infiltration device and is configured to extrude the blended fiber product infiltrated with water, so that the water inside the blended fiber product permeates outward under the action of mechanical force and brings out the degradation products of the second fiber.

2. The recycling system for blended fiber products according to claim 1, wherein: The physical separation device includes a classifier operatively connected to the extrusion device and configured to retain the extruded blended fiber product and allow water and degradation products of the second fiber to pass therethrough.

3. The recycling system for blended fiber products according to claim 2, wherein: The physical separation device includes a conveyor disposed between the water immersion device and the separator to provide a conveying path from the separator back to the water immersion device.

4. The recycling system for blended fiber products according to claim 3, wherein: The water soaking device is connected to the classifier through a filter to reuse the drainage of the classifier, and the filter is configured to filter out degradation products of the second fiber from the drainage of the classifier.

5. The recycling system for blended fiber products according to claim 1, wherein: The water impregnation device includes a sprinkler and a feeder, wherein the sprinkler is arranged above the feeder; wherein the sprinkler is arranged to spray water onto the blended fiber product that has undergone the hydrothermal degradation reaction, and the feeder is arranged to supply the blended fiber product impregnated with water to the extrusion device for extrusion.

6. The recycling system for blended fiber products according to claim 1 or 5, wherein: The squeezing device includes at least one squeezing roller group, which includes two rollers arranged opposite to each other, and the two rollers can be driven to rotate towards each other to press the blended fiber product soaked in water.

7. The recycling system for blended fiber products according to claim 6, wherein: The at least one squeezing roller assembly includes a first squeezing roller assembly and a second squeezing roller assembly that are sequentially arranged.

8. The recycling system for blended fiber products according to claim 1, wherein: The chemical separation equipment includes a reactor, and the reactor is configured to allow a catalyst aqueous solution to contact the blended fiber product to cause the hydrothermal degradation reaction.

9. The recycling system for blended fiber products according to claim 8, wherein: The chemical separation equipment includes a liquid storage tank for storing the catalyst aqueous solution; wherein a spray device is provided in the reactor, and the spray device is connected to the liquid storage tank through a circulation pipeline.

10. The recycling system for blended fiber products according to claim 9, wherein: The circulation pipeline is configured to allow the catalyst aqueous solution to circulate between the reactor and the liquid storage tank, and to be sprayed out from the spraying device to repeatedly contact the blended fiber product; wherein the contact frequency of the catalyst aqueous solution and the blended fiber product is 3 to 4 times per minute, and the solid-liquid ratio of the catalyst aqueous solution to the blended fiber product is 1:5-10.

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