Recycling system for blended fiber products

Abstract

A recycling system for a blended fiber product includes a chemical separation apparatus and a physical separation apparatus. The chemical separation apparatus is configured to subject a blended fiber product to a hydrothermal degradation reaction. In the hydrothermal degradation reaction, a first fiber in the blended fiber product does not undergo a chemical change while a second fiber undergoes degradation. The physical separation apparatus includes a water soaking device and a squeezing device. The water soaking device is operably connected to the chemical separation apparatus and is configured to soak the blended fiber product subjected to the hydrothermal degradation reaction with water. The squeezing device is operably connected to the water soaking device and is configured to squeeze the blended fiber product soaked with water, causing water inside the blended fiber product to permeate outward under mechanical force and carry degradation products of the second fiber out.

Description

Technical Field

[0001] This invention relates to a recycling system for fiber products, and more particularly to a recycling system for blended fiber products, such as finished products made from blends of polyester fibers with natural fibers such as cotton and wool. Background Technology

[0002] Polyester / cotton blends are widely used in clothing and home textiles because they combine the durability of polyester with the comfort of cotton. A huge amount of these products are discarded each year, with only a small portion entering the recycling system.

[0003] Furthermore, polyester / cotton blended fabrics have complex compositions and structures, resulting in high separation costs. The significant differences in physical and chemical properties between polyester and cotton fibers make it difficult to physically separate cotton fibers from polyester fibers using a single treatment method; a combination of different treatments is required, leading to a complex separation process. Therefore, TWI845823B discloses a method for sequentially mechanically decomposing, acid-treating, and alkali-treating blended fiber textile materials. Mechanical decomposition is used to open up 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 alkali treatment is used to remove non-cellulose components and further adjust the properties of cellulose.

[0004] WO2019047174A1 discloses a method of dividing 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-liquid ratio of 1:30-200, and then heating the mixed system to 110-180℃. This method requires a large amount of liquid, and the recovered polyester fibers still contain a small amount of cotton fragments, 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 that can separate polyester fibers and natural fibers such as cotton and wool from blended fiber products for high-purity recycling.

[0006] To address the aforementioned technical problems, one technical solution adopted by this 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 includes 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 change while the second fiber degrades. The physical separation device includes a water wetting device and a pressing device; the water wetting device is operatively connected to the chemical separation device and is configured to wet the blended fiber product after the hydrothermal degradation reaction; the pressing device is operatively connected to the water wetting device and is configured to press the water-wetted blended fiber product, causing the water inside the blended fiber product to permeate outwards under mechanical force and carry out the degradation products of the second fiber.

[0007] In a feasible or optional embodiment of the invention, the physical separation device includes a sorter. The sorter is operatively connected to the extrusion device and is configured to retain the extruded blended fiber article while allowing water and degradation products of the second fiber to pass through.

[0008] In a feasible or optional embodiment of the invention, the physical separation device includes a conveyor. The conveyor is disposed between the water immersion device and the sorter to provide a transport path from the sorter back to the water immersion device.

[0009] In a feasible or optional embodiment of the invention, the water immersion device is connected to the sorter via a filter to reuse the sorter's wastewater. Additionally, the filter is configured to remove degradation products of the second fiber from the sorter's wastewater.

[0010] In a feasible or optional embodiment of the present invention, the water-wetting device includes a sprinkler and a feeder, with the sprinkler disposed above the feeder. Furthermore, the sprinkler is configured to spray water onto the blended fiber product that has undergone the hydrothermal degradation reaction, and the feeder is configured to supply the water-wetted blended fiber product to the extrusion device for extrusion.

[0011] In a feasible or optional 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 arranged opposite each other, and the two rollers can be driven to rotate in opposite directions to crush the water-soaked blended fiber article.

[0012] In a feasible or optional embodiment of the present invention, the at least one extrusion roller group includes a first extrusion roller group and a second extrusion roller group arranged sequentially.

[0013] In a feasible or optional embodiment of the invention, the chemical separation apparatus includes a reactor. The reactor is configured to contact an aqueous catalyst solution with the blended fiber product to induce the hydrothermal degradation reaction.

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

[0015] In a feasible or optional embodiment of the present invention, the circulation pipeline is configured to circulate the catalyst aqueous solution between the reactor and the storage tank, and spray it from the spray device to repeatedly contact the blended fiber product. Furthermore, the contact frequency between 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.

[0016] In general, the blended fiber product recycling system provided by this invention, by means of "a chemical separation device configured to subject a blended fiber product to a hydrothermal degradation reaction", "a water wetting device of a physical separation device configured to wet the blended fiber product after the hydrothermal degradation reaction", and "an extrusion device of a physical separation device configured to extrude the water-wetted blended fiber product", can easily physically separate cotton fibers from polyester fibers from blended fiber products, ensuring excellent separation efficiency even under low solid-liquid ratio conditions; on this basis, the recycling purity of polyester fibers can be greater than 98%, while the recycling purity of cotton fibers can be 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. Attached Figure Description

[0018] Figure 1 This is a block diagram of one of the recycling systems for blended fiber products of the present invention.

[0019] Figure 2 This is another schematic diagram of the recycling system for blended fiber products of the present invention.

[0020] Figure 3 This is a partial structural diagram of the physical separation equipment of the recycling system for blended fiber products of the present invention.

[0021] Figure 4 This is a schematic diagram of the chemical separation equipment in the recycling system for blended fiber products of the present invention.

[0022] Figure 5 This is a flowchart of the recycling method for blended fiber products according to the present invention. Detailed Implementation

[0023] The following specific embodiments illustrate the implementation of the "recycling system for blended fiber products" disclosed in this invention. Those skilled in the art can understand the advantages and effects of this invention from the content disclosed in this specification. This invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of this invention. Furthermore, the accompanying drawings of this invention are for simple illustrative purposes only and are not depictions of actual dimensions; this is stated beforehand. The following embodiments will further describe the relevant technical content of this invention in detail, but the disclosed content is not intended to limit the scope of protection of this invention.

[0024] It should be understood that while terms such as "first," "second," and "third" may be used in this document 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 should, as appropriate, include any combination of one or more of the related listed items.

[0025] First Embodiment

[0026] See Figure 1 As shown, the first embodiment of the present invention provides a recycling system Z for blended fiber products, which includes 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 a hydrothermal degradation reaction; the blended fiber product may include 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 change while the second fiber degrades. The physical separation device 2 is operatively 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, using mechanical force to allow water to penetrate the blended fiber product, thereby carrying away the degradation products of the second fiber. Therefore, different fiber components can be separated from the blended fiber product for high-purity recycling. If necessary, the blended fiber product to be treated can be first divided into several fragments (small pieces) before undergoing 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. The polyester fiber may include polyethylene terephthalate (PET) fiber, polypropylene terephthalate (PPT) fiber, polybutylene terephthalate (PBT) fiber, poly(1,4-cyclohexanedimethyl terephthalate) (PCT) fiber, and / or polyethylene naphthalate (PEN) fiber.

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

[0029] Cooperate Figure 4 As shown, the chemical separation device 1 mainly includes a reactor 11, and a high-temperature and high-pressure closed environment can be formed inside the reactor 11. Furthermore, the reactor 11 is configured to allow a catalyst aqueous solution to contact the blended fiber product to undergo a hydrothermal degradation reaction; the contact method may include 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 catalyst aqueous solution contains at least one catalyst and water; based on 100 wt% of the total amount of the catalyst aqueous solution, the catalyst content can be 0.1 wt% to 10 wt%, optionally 3 wt% to 5 wt%. The catalyst suitable for this invention can be an organic acid, an organic anhydride, Lewis acid, or any combination thereof. It should be noted that increasing the catalyst content can accelerate the degradation rate of the second fiber in the blended fiber product, thereby shortening the reaction time, but it will also increase the cost.

[0031] Specific examples of organic acids include: methanesulfonic acid, oxalic acid, tartaric acid, citric acid, malic acid, formic acid, and acetic acid; oxalic acid can be selected as the organic acid used as a catalyst in aqueous solutions.

[0032] Specific examples of organic acid anhydrides include: acetic anhydride, propionic anhydride, butyric anhydride, valeric anhydride, lauric anhydride, palmitic anhydride, stearic anhydride, malonitic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, acrylic anhydride, cinnamic anhydride, phthalic anhydride, acetic and benzoic anhydride, amino acid anhydrides, and their derivatives; acetic anhydride may be selected as the catalyst for the aqueous solution of the catalyst.

[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 aqueous solutions, the Lewis acid may be selected from at least one of zinc chloride and ferric chloride.

[0034] In practical applications, the chemical separation device 1 may further include a storage tank 12 to store the catalyst aqueous solution, and the storage tank 12 is configured to provide the catalyst aqueous solution to the reactor 11. In an example where the catalyst aqueous solution is circulated through the blended fiber product, a spray device 111 may be provided in the reactor 11, and the spray device 111 is connected to the storage tank 12 via a circulation pipe 13, wherein a circulation pump 14 is installed on the spray device 111. Thus, the catalyst aqueous solution can repeatedly contact the blended fiber product in a circulating manner, that is, the catalyst aqueous solution, under the action of the circulation pump 14, travels back and forth between the reactor 11 and the storage tank 12 via the circulation pipe 13, and is sprayed out from the spray device 111 to repeatedly contact the blended fiber product.

[0035] Furthermore, the catalyst aqueous solution is pumped from the bottom of reactor 11 to storage tank 12 via circulation pump 14 through upstream side 131 of circulation pipeline 13; and the catalyst aqueous solution in storage tank 12 is pumped to spray device 111 for recycling via downstream side 132 of circulation pipeline 13 by circulation pump 14. The entire process can be fully automated. During the hydrothermal degradation reaction under such operation, the contact frequency between 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. Therefore, the chemical separation device 1 can react at a lower solid-liquid ratio, thereby significantly reducing the amount of catalyst aqueous solution used and lowering costs. In addition, the chemical separation device 1 does not use any solvents during the hydrothermal degradation reaction, and will not cause harm to the environment.

[0036] Cooperate Figure 2 As shown, the physical separation device 2 mainly includes a water wetting device 21 and an extrusion device 22. The water wetting device 21 is operatively connected to the chemical separation device 1, and is configured to wet the blended fiber product that has undergone hydrothermal degradation reaction with water. The extrusion device 22 is operatively connected to the water wetting device 21, and is configured to extrude the water-wetted blended fiber product, causing the water inside the blended fiber product to permeate outward under the action of mechanical force and carry out the degradation products of the second fiber.

[0037] Further cooperation Figure 3As shown, 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 that has undergone hydrothermal degradation. 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. In addition, the extrusion device 22 may include at least one set of extrusion rollers 221, which operates by using two opposing rollers to roll and extrude the water-containing material from the blended fiber product, while simultaneously carrying out the degradation products of the second fiber.

[0038] Furthermore, the extrusion roller assembly 221 may include two rollers arranged opposite each other, and the two rollers can be driven to rotate in opposite directions; when the water-soaked blended fiber product falls between the two rollers through the feeder 212, it is subjected to the opposing rolling extrusion of the two rollers. Depending on the needs, the extrusion device 22 may include multiple extrusion roller assemblies to increase extrusion efficiency. For example, the extrusion device 22 may include an upper row of extrusion roller assemblies 221 and a lower row of extrusion roller assemblies 221 to perform secondary extrusion on the water-soaked blended fiber product, thereby extruding more degradation products of the second fiber.

[0039] See also Figure 2 As shown, in practical applications, the physical separation device 2 may further include a separator 23 to facilitate the recovery of the first fiber from the blended fiber product. The separator 23 is operatively 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; the separator 23 may be a screen separator, but is not limited thereto. Additionally, the physical separation device 2 may further include a filter 24, configured to filter out degradation products of the second fiber from the wastewater of the separator 23, facilitating the reuse of the wastewater from the separator 23.

[0040] To improve the operability and usability of the system, the physical separation device 2 may further include a conveyor 25. The conveyor 25 is positioned between the water-soaking device 21 and the sorter 23 to provide a transport path (fabric circulation path) from the sorter 23 back to the water-soaking device 21; the conveyor 25 may include one or more belt conveyors, but is not limited thereto. Therefore, the extruded blended fiber product can be repeatedly soaked in water and extruded at least once more, thereby extruding more degradation products of the second fiber.

[0041] Second Embodiment

[0042] See Figure 5As shown, the 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, immersing the hydrothermally degraded blended fiber product in water; and step S3, compressing the water-immersed blended fiber product. The method for recycling blended fiber products of the present invention can be implemented using the system described in the first embodiment to achieve the separation and recycling of different fiber components (such as polyester fiber and cotton fiber) in the blended fiber product.

[0043] In step S1, a catalyst aqueous solution can be brought into contact with the blended fiber product to undergo a hydrothermal degradation reaction; the contact method may include immersing the blended fiber product in the catalyst aqueous solution or circulating the catalyst aqueous solution through the blended fiber product. In the hydrothermal degradation reaction, the first fiber of the blended fiber product will not degrade, while the second fiber will degrade and separate from the first fiber in the form of degradation products.

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

[0045] In step S2, water can be sprayed onto the blended fiber product that has undergone hydrothermal degradation reaction to allow it to absorb water and become wetted. In step S3, the water-containing material of the blended fiber product can be squeezed out by rolling and pressing with rollers, while simultaneously carrying out the degradation products of the second fiber.

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

[0047] Beneficial effects of the embodiments

[0048] The recycling system for blended fiber products provided by this invention, by means of "a chemical separation device configured to subject a blended fiber product to a hydrothermal degradation reaction", "a water wetting device of a physical separation device configured to wet the blended fiber product after the hydrothermal degradation reaction", and "an extrusion device of a physical separation device configured to extrude the water-wetted blended fiber product", can easily physically separate cotton fibers from polyester fibers from blended fiber products, ensuring excellent separation efficiency even under low solid-liquid ratio conditions; on this basis, the recycling purity of polyester fibers can be greater than 98%, while the recycling purity of cotton fibers can be greater than 99%.

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

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

[0051] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of protection of the claims of the present invention. Therefore, all equivalent technical changes made based on the content of the present invention specification and drawings are included within the scope of protection of the claims of the present invention.

Claims

1. A recycling system for blended fiber products, characterized in that, The recycling system for the blended fiber products includes: A chemical separation apparatus 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 change while the second fiber degrades; and A physical separation device, comprising a water immersion device and a pressing device; The water immersion device is operable and connected to the chemical separation equipment, and is configured to immerse the blended fiber product that has undergone the hydrothermal degradation reaction in water. The extrusion device is operablely connected to the water-immersion device and is configured to extrude the water-immersed blended fiber product, causing the water inside the blended fiber product to permeate outward under the action of mechanical force and carry out the degradation products of the second fiber.

2. The recycling system for blended fiber products according to claim 1, characterized in that, The physical separation device includes a separator operably connected to the extrusion device and configured to retain the extruded blended fiber product while allowing water and degradation products of the second fiber to pass through.

3. The recycling system for blended fiber products according to claim 2, characterized in that, The physical separation device includes a conveyor disposed between the water immersion device and the sorter to provide a transport path from the sorter back to the water immersion device.

4. The recycling system for blended fiber products according to claim 3, characterized in that, The water immersion device is connected to the sorter via a filter to reuse the sorter's wastewater, and the filter is configured to remove degradation products of the second fiber from the sorter's wastewater.

5. The recycling system for blended fiber products according to claim 1, characterized in that, The water-soaking device includes a sprinkler and a feeder, with the sprinkler positioned above the feeder. The sprinkler is configured to spray water onto the blended fiber product that has undergone the hydrothermal degradation reaction, and the feeder is configured to supply the water-soaked blended fiber product to the extrusion device for extrusion.

6. The recycling system for blended fiber products according to claim 1 or 5, characterized in that, The extrusion device includes at least one extrusion roller assembly, which includes two opposing rollers, and the two opposing rollers can be driven to rotate in opposite directions to crush the water-soaked blended fiber product.

7. The recycling system for blended fiber products according to claim 6, characterized in that, The at least one extrusion roller group includes a first extrusion roller group and a second extrusion roller group arranged sequentially.

8. The recycling system for blended fiber products according to claim 1, characterized in that, The chemical separation device includes a reactor configured to contact an aqueous catalyst solution with the blended fiber product to induce the hydrothermal degradation reaction.

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

10. The recycling system for blended fiber products according to claim 9, characterized in that, The circulation pipeline is configured to allow the catalyst aqueous solution to circulate between the reactor and the storage tank, and to be sprayed out from the spray device to repeatedly contact the blended fiber product; wherein the contact frequency between 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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