Recovery system, recovery method, and storage medium

Abstract

The present invention relates to a recovery system, a recovery method, and a storage medium, the recovery system comprising: a quality determination unit (710) that determines the quality of a solid material such as PET fragments including a polymer to be recovered on the basis of a predetermined quality determination criterion; a material sorting unit (720) for sorting the solid material into a high-quality material for which the quality is determined to be higher than the quality determination standard and a low-quality material for which the quality is determined to be lower than the quality determination standard; a mechanical recovery device (900) for mechanically recovering the high-quality material; and a chemical recovery device (100) that performs a chemical recovery process on the low-quality material. A chemical recovery device (100) is provided with: a depolymerization reaction tank (300) for decomposing a low-quality material into a depolymerized product by a depolymerization reaction; foreign matter removal devices (340-360) for removing foreign matters from the depolymerized material; a polymerization reaction tank (400) for synthesizing the depolymerized product into a polymer by a polymerization reaction; and a polymerization promoting device (500) for improving the degree of polymerization of the polymer.

Description

Technical Field

[0001] This invention relates to a recycling system, etc. Background Technology

[0002] Patent Document 1 discloses a method for manufacturing PET fragments, which are raw materials for new PET bottles, by crushing PET bottles for recycling. Specifically, mechanical recycling methods are known, such as heating and melting crushed PET bottles and obtaining PET fragments through solid-state polymerization, and chemical recycling methods are known, such as depolymerizing crushed PET bottles into intermediates or depolymers like bis(2-hydroxyethyl) terephthalate (BHET) through a depolymerization reaction and then obtaining PET fragments through a repolymerization reaction.

[0003] Previous technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2016-153176 Patent Document 2: Japanese Patent Application Publication No. 2022-27158 Summary of the Invention

[0004] The technical problem to be solved by the invention The quality of PET fragments and PET pellets (hereinafter simply referred to as fragments and pellets, and also including fragments and pellets not made from PET) depends on the quality of the PET bottles and the like that used as their raw materials. Thus, even if the same recycling process (mechanical recycling or chemical recycling) is applied to such fragments and pellets that may have quality deviations, PET bottles and the like will still be produced with inconsistent quality.

[0005] The present invention was made in view of the following circumstances, and its object is to provide a recycling system, etc., that can stabilize the quality of recycled materials.

[0006] means for solving technical problems To address the aforementioned issues, one embodiment of the recycling system of the present invention includes: a quality determination unit for determining the quality of a solid material containing a polymer to be recycled based on a predetermined quality determination criterion; a material sorting unit for sorting the solid material into high-quality material determined to be of higher quality than the quality determination criterion and low-quality material determined to be of lower quality than the quality determination criterion; a mechanical recycling device for mechanically recycling the high-quality material; and a chemical recycling device for chemically recycling the low-quality material.

[0007] In this embodiment, solid materials are sorted into high-quality materials and low-quality materials according to quality judgment criteria. High-quality materials are efficiently recovered through mechanical recycling processes, which have low quality improvement effects but require simple equipment, while low-quality materials are recovered through chemical recycling processes, which have high quality improvement effects, thus improving their quality. Therefore, according to this embodiment, by applying appropriate recycling processes (mechanical or chemical) corresponding to the quality of the solid materials, the quality of the recovered products can be stabilized.

[0008] Another embodiment of the present invention is a recycling method. This method is performed by a computer using the following steps: determining the quality of the solid material to be recycled according to a predetermined quality assessment criterion; sorting the solid material into high-quality material (determined to be of higher quality than the quality assessment criterion) and low-quality material (determined to be of lower quality than the quality assessment criterion); mechanically recycling the high-quality material; and chemically recycling the low-quality material.

[0009] Another embodiment of the present invention is a storage medium. This storage medium stores a recycling program executed by a computer, comprising the following steps: determining the quality of the solid material to be recycled based on a predetermined quality assessment criterion; sorting the solid material into high-quality material (determined to be of higher quality than the quality assessment criterion) and low-quality material (determined to be of lower quality than the quality assessment criterion); performing mechanical recycling processing on the high-quality material; and performing chemical recycling processing on the low-quality material.

[0010] Furthermore, any combination of the above-mentioned constituent elements, and the manner in which these expressions are transformed into methods, apparatus, systems, storage media, computer programs, etc., are also included in this invention.

[0011] Invention Effects According to the present invention, the quality of recycled products can be stabilized. Attached Figure Description

[0012] Figure 1 The structure of a chemical recycling molding system is schematically shown.

[0013] Figure 2 The polymerization and depolymerization reactions of PET are schematically illustrated.

[0014] Figure 3 A horizontal stirring device is schematically shown.

[0015] Figure 4 The structure of the chemical recycling molding system involved in the modified example is schematically shown.

[0016] Figure 5 The recycling system according to the second embodiment is shown schematically.

[0017] Figure 6The diagram schematically shows the quality assessment department and material sorting department, which are generally integrated.

[0018] Figure 7 The recycling system according to the third embodiment is shown schematically.

[0019] Figure 8 The diagram schematically shows a partially depolymerization section and a solid-liquid separation section that are generally integrally formed.

[0020] Figure 9 schematically shown Figure 8 A modified example of the processing device shown.

[0021] Figure 10 schematically shown Figure 8 A modified example of the processing device shown.

[0022] Figure 11 schematically shown Figure 8 A modified example of the processing device shown.

[0023] Figure 12 schematically shown Figure 7 The structure of the recycling system involved in the variation example.

[0024] Figure 13 The depolymerization reaction is illustrated schematically.

[0025] Figure 14 The first embodiment of the mechanical mixing unit is schematically shown.

[0026] Figure 15 The second embodiment of the mechanical mixing unit is schematically shown.

[0027] Figure 16 The third embodiment of the mechanical mixing unit is schematically shown.

[0028] Figure 17 The fourth embodiment of the mechanical mixing unit is schematically shown.

[0029] Figure 18 The recycling system according to the fourth embodiment is shown schematically.

[0030] Figure 19 The recycling system according to the fifth embodiment is shown schematically.

[0031] Figure 20 The recycling system according to the sixth embodiment is shown schematically.

[0032] Figure 21 The recycling system according to the seventh embodiment is shown schematically.

[0033] Figure 22 The recycling system according to the eighth embodiment is shown schematically.

[0034] Figure 23 The recycling system according to the 9th embodiment is shown schematically. Detailed Implementation

[0035] Hereinafter, embodiments for carrying out the present invention (hereinafter also referred to as embodiments) will be described in detail with reference to the accompanying drawings. In the following description and / or drawings, the same or equivalent constituent elements, components, and processes are labeled with the same reference numerals, and repeated descriptions are omitted. For ease of description, the proportions or shapes of the parts are appropriately set in the drawings, which are not intended to be limiting unless otherwise specified. The embodiments are illustrative and do not limit the scope of the present invention in any way. All features or combinations thereof shown in the embodiments are not necessarily essential to the present invention. For convenience, embodiments are shown by breaking them down into constituent elements that implement each function and / or each group of functions of the embodiment. However, one constituent element in an embodiment may be implemented by a combination of multiple constituent elements that are actually separate entities, and multiple constituent elements in an embodiment may be implemented by a single constituent element that is actually a single entity.

[0036] Figure 1 The structure of a chemical recycling molding system, as one embodiment of the recycling system according to the present invention, is schematically shown. As described below, the recycling system according to the present invention can be configured as a mechanical recycling molding system, or as a hybrid recycling molding system incorporating both a chemical recycling device and a mechanical recycling device. Furthermore, Figure 1 The recycling molding system (chemical recycling molding system) illustrated herein includes a recycling device (chemical recycling device 100) and a molding machine (injection molding machine 1), but the recycling system involved in this invention may also not include a molding machine.

[0037] Figure 1 The chemical recycling molding system shown includes a chemical recycling unit 100 and an injection molding machine 1. The chemical recycling unit 100 performs chemical recycling treatment on first molded articles such as PET bottles and / or solid materials such as PET fragments and PET granules derived from various first molded articles, as described in detail below.

[0038] The chemical recovery unit 100 includes a polymer conditioning unit 200, a depolymerization reaction tank 300, a polymerization reaction tank 400, a polymerization promotion unit 500, and a polymer supply unit 600. Injection molding machine 1 (in...) Figure 1The diagram schematically shows two units of the injection molding machine 1. The number of polymer conditioning unit 200, depolymerization reaction tank 300, polymerization reaction tank 400, polymerization accelerator 500, and polymer supply unit 600 is arbitrary. In particular, typically, by having an injection molding machine 1 with a slower processing speed or reaction speed than other processing units, and by having more polymerization reaction tanks 400 than other processing units, processing performance can be improved in a way that prevents these processing units from becoming serious bottlenecks.

[0039] The polymer conditioning device 200 conditions the polymers, such as PET, that constitute the first molded product (e.g., PET bottles) and / or solid materials such as PET fragments, for use in the subsequent depolymerization reaction tank 300. Specifically, the polymer conditioning device 200 processes the first molded product and / or solid materials such as PET fragments through crushing, heating, melting, and mixing to condition the polymers (e.g., phase, shape, size) suitable for the depolymerization reaction in the depolymerization reaction tank 300. Furthermore, the first molded product can be any molded product other than bottles, such as sheets, films, or fibers. And the polymers constituting the first molded product and / or solid materials can be any polymer other than PET, such as polyester (including PET), polyamide, or polyurethane.

[0040] The polymer conditioning device 200 can perform crushing or other processing on first-molded products such as PET bottles to generate solid materials such as PET fragments. Furthermore, if the depolymerization reaction tank 300 can accept it, the pre-formed solid materials such as PET fragments can be directly fed into the depolymerization reaction tank 300 without passing through the polymer conditioning device 200. Moreover, as described later, a quality determination unit for judging the quality of solid materials such as PET fragments, a material sorting unit for separating solid materials into high-quality and low-quality materials, a partial depolymerization unit for partially decomposing solid materials such as PET fragments, and a solid-liquid separation unit for separating the solid and liquid components obtained from the partial depolymerization unit can be provided in the upstream section of the polymer conditioning device 200 and / or the depolymerization reaction tank 300.

[0041] The depolymerization reactor 300 decomposes polymers, such as recycled PET, contained in solid materials like PET fragments into depolymerized products through a depolymerization reaction. When the polymer supplied to the depolymerization reactor 300 is PET, BHET, an intermediate, is obtained as a depolymerized product through the depolymerization reaction in the reactor 300. Furthermore, the depolymerized product obtained in the depolymerization reactor 300 may contain polymer monomers. Examples of monomers when the polymer is PET include ethylene glycol, terephthalic acid, dimethyl terephthalate, and ethylene glycol terephthalate.

[0042] like Figure 2 The diagram schematically illustrates that in the depolymerization reaction (300) of PET as a polymer, the depolymerization material is supplied from the depolymerization material supply section 310 ( Figure 1Ethylene glycol (EG), supplied as a depolymerization material, is fed into the depolymerization reaction tank 300 to decompose PET and obtain BHET as a depolymerized product. Alternatively, EG can be supplied to the polymer conditioning device 200 in place of the depolymerization material supply unit 310, or it can be supplied to the polymer conditioning device 200 in addition to the depolymerization material supply unit 310. To promote this depolymerization reaction, a heater 320 attached to the depolymerization reaction tank 300 is used. Figure 1 (or a heatsink) to maintain the depolymerization reaction tank 300 at a temperature suitable for the depolymerization reaction. Figure 2 The suitable temperature for the depolymerization reaction of PET to BHET is between 220°C and 250°C, preferably between 230°C and 245°C, and more preferably between 235°C and 240°C. Furthermore, Figure 2 The pressure suitable for the depolymerization reaction of PET to BHET is between 0.3 MPa and 0.8 MPa, preferably between 0.4 MPa and 0.6 MPa, and more preferably between 0.45 MPa and 0.55 MPa. The pressure inside the depolymerization reaction tank 300 is adjusted by a pump (not shown) or the like attached to the depolymerization reaction tank 300.

[0043] The fluid viscosity in the depolymerization reaction tank 300, which produces BHET with a molecular weight smaller than PET, is lower than the fluid viscosity in the polymerization reaction tank 400, which produces PET with a larger molecular weight (described later). Therefore, a low-viscosity stirring blade is used as the stirring blade 330 for stirring the fluid in the depolymerization reaction tank 300 to promote the depolymerization reaction. Examples of low-viscosity stirring blades 330 include propeller blades, disc turbine blades, and paddle blades.

[0044] A foreign matter removal device 340, 350, and 360 are provided downstream of the depolymerization reaction tank 300 to remove foreign matter from the fluid, which is mainly composed of BHET as a depolymerized product. The foreign resin removal device 340 removes resins different from the target resin such as PET and / or their depolymerized products using the principles of flotation separation and sedimentation removal. The colorant removal device 350 removes colorants using activated carbon or similar methods. The metal ion removal device 360 ​​removes metal ions using principles such as ion exchange. A buffer tank 370 is provided downstream of the foreign matter removal devices 340, 350, and 360 to temporarily store the fluid, which is mainly composed of BHET and other foreign matter after foreign matter removal, before it is supplied to the polymerization reaction tank 400.

[0045] A first preheater 371 can be installed in the buffer tank 370 to heat or maintain the temperature of the depolymerized material (a fluid mainly composed of BHET, etc.) before it is supplied to the polymerization reactor 400. The first preheater 371 can maintain the depolymerized material at the same temperature (between 220°C and 250°C) as the heater 320 attached to the depolymerization reactor 300, or at the same temperature suitable for polymerization (between 250°C and 300°C) as the heater 410 attached to the polymerization reactor 400 (described later). Thus, by installing the buffer tank 370 equipped with the preheating mechanism (first preheater 371) in front of the polymerization reactor 400 as needed, it is typically possible to store the depolymerized material waiting to be fed into the polymerization reactor 400, whose processing speed or reaction speed is slower than that of the depolymerization reactor 300, the polymerization accelerator 500 (described later), etc., at a suitable temperature. As a result, the overall capacity of the chemical recovery unit 100 is increased, enabling the chemical recovery unit 100 to operate stably and continuously while supplying appropriate amounts of reactants to each processing unit, such as the depolymerization reaction tank 300, polymerization reaction tank 400, polymerization accelerator 500, and polymer supply unit 600, in a timely manner (without the so-called "resin supply interruption"). Furthermore, the preheating mechanism, such as the first preheater 371, is not limited to the buffer tank 370 and can be installed in any manner at any location between the depolymerization reaction tank 300 and the polymerization reaction tank 400 (e.g., foreign matter removal devices 340, 350, 360).

[0046] The polymerization reactor 400 synthesizes depolymerized products such as BHET, which were generated in the depolymerization reactor 300 and had their foreign matter removed by the foreign matter removal devices 340, 350, and 360, into a polymer through a polymerization reaction. If the depolymerized product generated in the depolymerization reactor 300 is BHET, PET, as a polymer, can be obtained again through the polymerization reaction in the polymerization reactor 400.

[0047] like Figure 2 The diagram schematically illustrates that in the polymerization reaction (400) of BHET, which is a depolymerizer, EG is generated as a byproduct along with PET, which is the main product of the polymer. This EG can be recycled to the depolymerization material supply unit 310 and used in the depolymerization reaction of PET in the depolymerization reaction tank 300. Since the EG generated in the polymerization reaction tank 400 is not wasted and can be reused on-site (in the depolymerization reaction tank 300), the operating efficiency of the chemical recovery unit 100 can be improved. In particular, since the amount of EG used for the depolymerization reaction of PET in the depolymerization reaction tank 300 can be significantly reduced, the operating cost of the chemical recovery unit 100 is reduced.

[0048] To promote the above-mentioned polymerization reaction, a heater 410, which serves as a second heater, is attached to the polymerization reaction tank 400. Figure 1(or a heatsink) to maintain the polymerization reactor 400 at a temperature suitable for the polymerization reaction. Figure 2 The suitable temperature for the polymerization reaction of BHET to PET is between 250°C and 300°C, preferably between 260°C and 290°C, and more preferably between 270°C and 280°C. Here, the polymerization heating temperature based on the heater 410 attached to the polymerization reactor 400 is higher than the depolymerization heating temperature based on the heater 320 attached to the depolymerization reactor 300. PET with a high molecular weight and high melting point is generated in the polymerization reactor 400, but by maintaining a temperature higher than that of the depolymerization reactor 300 which generates BHET with a lower molecular weight and low melting point, the PET, as the main product of the polymerization reactor 400, is kept in a molten state. Furthermore, Figure 2 The polymerization reaction of BHET to PET is preferably carried out under vacuum. Therefore, a vacuum pump (not shown) is provided in the polymerization reaction tank 400.

[0049] Since the fluid viscosity in the polymerization reactor 400, which produces PET with a large molecular weight, is higher than the fluid viscosity in the depolymerization reactor 300, which produces BHET with a smaller molecular weight than PET, a high-viscosity stirring blade is used as the stirring blade 420 for stirring the fluid in the polymerization reactor 400 to promote the polymerization reaction. Examples of high-viscosity stirring blades 420 include anchor blades and helical ribbon blades.

[0050] As a numerical value related to the degree of polymerization of polymers such as PET, the intrinsic viscosity (IV) value is known. The IV value (dL / g) is also used as an indicator of the polymer's intended use. In PET, an IV value of approximately 0.72 or higher is suitable for bottles, an IV value of approximately 0.65 or higher is suitable for sheets or films, and an IV value of approximately 0.58 or higher is suitable for fibers. In this embodiment, the aim is to ultimately obtain PET with an IV value suitable for bottles or sheets. As described later, since the IV value can also be increased in the polymerization accelerator 500 and / or the polymer supply unit 600 at the downstream end of the polymerization reactor 400, the IV value of the PET synthesized in the polymerization reactor 400 can be relatively low. Specifically, the IV value of the PET synthesized in the polymerization reactor 400 is between 0.2 and 0.7, preferably between 0.3 and 0.7, and more preferably between 0.3 and 0.55.

[0051] A buffer tank 430 may be provided at the downstream end of the polymerization reactor 400 to temporarily store the polymer synthesized in the polymerization reactor 400 before it is supplied to the polymerization accelerator 500 and / or the polymer supply unit 600. A second preheater 431 may be provided in the buffer tank 430 to heat or maintain the polymer before it is supplied to the polymerization accelerator 500 and / or the polymer supply unit 600. The second preheater 431 may maintain the polymer at the same temperature (between 250°C and 300°C) as the heater 410 attached to the polymerization reactor 400, or at the same temperature (between 250°C and 290°C) suitable for polymerization (between 250°C and 290°C) as the heater 520 attached to the polymerization accelerator 500 (described later), or at the same temperature (between 250°C and 290°C) as the heater 620 attached to the polymer supply unit 600 (described later).

[0052] Thus, by providing a buffer tank 430 equipped with a preheating mechanism (second preheater 431) at the front end of the polymerization accelerator 500 and / or the polymer supply unit 600 as needed, the polymer waiting to be added to the polymerization accelerator 500 and / or the polymer supply unit 600 can be stored at a suitable temperature. As a result, the overall capacity of the chemical recovery unit 100 is increased, and the chemical recovery unit 100 can be stably and continuously operated while timely supplying appropriate amounts of reactants to each processing unit such as the depolymerization reaction tank 300, polymerization reaction tank 400, polymerization accelerator 500, and polymer supply unit 600 (without the so-called "resin supply interruption"). In addition, the preheating mechanism, such as the second preheater 431, is not limited to the buffer tank 430 and can be provided in any position between the polymerization reaction tank 400 and the polymerization accelerator 500 and / or between the polymerization accelerator 500 and the polymer supply unit 600 in any manner.

[0053] In the rear section of the polymerization reactor 400 (and in the front section of the polymer supply section 600 described later), a byproduct removal device or polymerization promotion device 500 can be provided to remove EG as a byproduct by allowing the PET (main product) and EG (byproduct) generated by the polymerization reaction in the polymerization reactor 400 to flow through. The polymerization promotion device 500 illustrated in the figure has multiple linear members 510 extending from top to bottom. Due to the increased surface area through the multiple linear members 510, the volatilization of EG adhering to the surface of each linear member 510 is promoted, and EG is effectively separated and removed from the high-viscosity PET.

[0054] The EG can be returned to the depolymerization material supply unit 310 for use in the depolymerization reaction of PET in the depolymerization reactor 300. Since the EG removed in the polymerization accelerator 500 is not wasted and can be reused on-site (in the depolymerization reactor 300), the operating efficiency of the chemical recovery unit 100 can be improved. In particular, since the amount of EG required for the depolymerization reaction of PET in the depolymerization reactor 300 can be significantly reduced, the operating cost of the chemical recovery unit 100 is reduced.

[0055] Furthermore, since PET with a relatively low degree of polymerization (i.e., IV value) and BHET that did not react in the polymerization reactor 400 are also attached to the surface of each linear component 510, the same polymerization reaction as in the polymerization reactor 400 can be carried out effectively due to the larger surface area. Therefore, by circulating in the polymerization accelerator 500, the IV value of PET, which is the main product, is increased. Specifically, the IV value of PET after circulating in the polymerization accelerator 500 is 0.7 or more, preferably 0.8 or more, and more preferably 0.85 or more.

[0056] To promote such a polymerization reaction, a heater 520, which serves as a second heater, is attached to the polymerization promotion device 500. Figure 1 A heater or insulator is used to maintain the polymerization accelerator 500 at a temperature suitable for the polymerization reaction. Specifically, the heating temperature of the heater 520 is between 250°C and 290°C, preferably between 260°C and 280°C. Here, the heating temperature of the heater 520 attached to the polymerization accelerator 500 is preferably higher than the polymerization heating temperature of the heater 410 attached to the polymerization reaction tank 400. In the polymerization accelerator 500, the polymerization reaction progresses more rapidly than in the polymerization reaction tank 400, thus the molecular weight of PET as a polymer increases and its melting point increases. Therefore, by maintaining the temperature inside the polymerization accelerator 500 at a higher temperature than that inside the polymerization reaction tank 400, the PET, as a product of the polymerization accelerator 500, can be kept in a molten state. In addition, a heater or insulator, serving as a second heater, can be provided around the piping or the like between the polymerization reaction tank 400 and the polymerization accelerator 500 to at least heat or keep warm to the polymerization heating temperature based on the heater 410 attached to the polymerization reaction tank 400. Furthermore, the polymerization reaction within the polymerization accelerator 500 is preferably carried out under a vacuum, similar to the polymerization reaction in the polymerization reactor 400. Therefore, a vacuum pump (not shown) is provided in the polymerization accelerator 500. By keeping the polymerization accelerator 500 under a vacuum (reduced pressure), EG, as a byproduct, can be removed efficiently.

[0057] Furthermore, the structure of the polymerization accelerator 500 is not limited to that shown. Figure 1 The "vertical" configuration is shown. For example, it can be like... Figure 3 The "horizontal" stirring device shown is used as a polymerization accelerator 500. This stirring device is equipped with a horizontal stirring mechanism. Figure 3 The system consists of two rotating shafts extending perpendicularly to the paper surface and two sets of stirring blades that rotate around each shaft to agitate PET and EG, the objects of the agitation. By utilizing the two sets of stirring blades to agitate and promote the volatilization of EG, EG can be effectively separated and removed from high-viscosity PET. Furthermore, Figure 3 Detailed information about the stirring device is disclosed in Japanese Patent No. 2925599, which is incorporated herein by reference. The structure or function of such a "vertical," "horizontal," or other polymerization accelerator 500 can also be implemented as part of the polymer supply unit 600 described later. In this case, it is not necessary to provide the polymerization accelerator 500 separately from the polymer supply unit 600.

[0058] The polymer supply unit 600 supplies polymers such as PET synthesized in the polymerization reaction tank 400 and / or polymerization accelerator 500 to the injection molding machine 1 for molding second-stage products such as PET bottles. The polymer supply unit 600 is equipped with a delivery pump 610, such as a gear pump or screw pump, suitable for supplying high-purity and high-viscosity (i.e., high degree of polymerization or high IV value) PET in a molten state to the injection molding machine 1, where EG, which is removed as a byproduct in the polymerization accelerator 500, is removed.

[0059] A heater 620 or a heatsink, serving as a first heater, is provided in the polymer supply section 600 to heat or keep the polymer, such as PET, supplied to the injection molding machine 1 by the transfer pump 610 in a molten state. Specifically, the heating temperature of the heater 620 is between 250°C and 290°C, preferably between 260°C and 280°C. Here, the heating temperature of the heater 620 (first heater) in the polymer supply section 600 (first heating temperature) is preferably higher than the second heating temperature of a second heater, such as the heater 410 attached to the polymerization reactor 400, the heater 520 attached to the polymerization accelerator 500, or a heater (not shown) located between the polymerization reactor 400 and the polymerization accelerator 500. As the polymerization reaction that begins in the polymerization reactor 400 proceeds gradually and is completed in the polymerization accelerator 500, the molecular weight of the polymer, such as PET, in the polymer supply section 600 is larger and the melting point is higher than that in the polymerization reactor 400 and the polymerization accelerator 500. Therefore, by setting the first heating temperature in the polymer supply section 600 to a higher than the previous second heating temperature, polymers such as PET with high viscosity (i.e., high degree of polymerization or high IV value) and high melting point can be maintained in a molten state. Furthermore, a vacuum pump (not shown) can also be installed in the polymer supply section 600. By keeping the polymer supply section 600 under vacuum (reduced pressure), the degree of polymerization can also be increased within the polymer supply section 600.

[0060] A temperature gradient can be set such that the heating temperature gradually increases from the polymerization reactor 400 to the polymer supply unit 600. For example, compared to the heating temperature based on the heater 410 attached to the polymerization reactor 400, the heating temperature based on a heater (not shown) located between the polymerization reactor 400 and the polymerization accelerator 500 can be increased; compared to the heating temperature based on the heater (not shown), the heating temperature based on the heater 520 attached to the polymerization accelerator 500 can be increased; and compared to the heating temperature based on the heater 520, the heating temperature based on the heater 620 located in the polymer supply unit 600 can be increased. This allows polymers such as PET, whose melting point increases from the polymerization reactor 400 to the polymer supply unit 600, to be reliably maintained in a molten state. Alternatively, a heater can be provided between the polymer supply unit 600 and the injection molding machine 1 to heat or maintain the polymer such as PET in a molten state.

[0061] The injection molding machine 1 molds molten polymers such as PET generated in the chemical recycling unit 100 into a second molded product. The second molded product can be the same type as or different from the first molded product, which undergoes pulverization or other processing in the polymer conditioning unit 200. For example, both the first and second molded products can be PET bottles. Alternatively, one of the first and second molded products can be a PET bottle, and the other can be a molded product other than a bottle, such as a sheet, film, or fiber. Typically, in mechanical recycling, the IV value of the recycled second molded product is lower than the IV value of the first molded product and / or solid material before recycling. However, according to the chemical recycling unit 100 of this embodiment, which includes mechanisms for increasing IV value such as foreign matter removal devices 340, 350, 360, and polymerization promotion device 500, it is also possible to make the IV value of the recycled second molded product higher than the IV value of the first molded product and / or solid material before recycling. For example, according to this embodiment, PET fibers with low IV values, which are the first molded product and / or solid material, can be recycled into PET bottles with high IV values ​​as the second molded product.

[0062] Injection molding machine 1 molds molten resin such as PET into a second molded article. An injection molding machine using molten resin as raw material is disclosed, for example, in Patent Document 2. This application incorporates the entire contents of that document (Japanese Patent Application 2020-130985), filed July 31, 2020, by reference. Figure 1 As schematically shown, multiple injection molding machines 1 can be arranged in parallel. In addition, the molding machine that supplies molten resin, etc. from the chemical recovery unit 100 can be any molding machine (e.g., a compression molding machine), not limited to injection molding machines.

[0063] In this embodiment described above, the polymer synthesized in the polymerization reactor 400 is not made into fragments or granules, but is directly supplied to the injection molding machine 1 by the polymer supply unit 600. Since the cooling and heating processes associated with fragments and granules are not required as in the past, molded products such as PET bottles can be recycled with less energy.

[0064] In the chemical recovery apparatus 100 according to this embodiment, since the polymer resynthesized in the polymerization reaction tank 400 is directly supplied to the injection molding machine 1, it is necessary to achieve the required IV value of the polymer for its molded article (second molded article) at high speed. In this embodiment, in addition to the polymerization reaction tank 400, a polymerization promotion device 500 and / or a polymer supply unit 600 with the function of promoting the polymerization reaction to improve the IV value of the polymer are also provided, so such requirements can be fully met.

[0065] Figure 4 The structure of the chemical recycling molding system involved in the modified example is schematically shown. (Regarding...) Figure 1The same components are labeled with the same reference numerals, and repeated descriptions are omitted. In this modified example, a polymer return section 1000 is provided to return at least a portion of the polymer synthesized in the polymerization reactor 400 to the polymerization reactor 400 and / or the depolymerization reactor 300. The polymer return section 1000 in the example is located between the by-product removal device 500 and the polymer supply section 600, but is not limited thereto. The polymer return section 1000 can be located at any position between the by-product removal device 500 and the injection molding machine 1. For example, the polymer return section 1000 can be located between the polymer supply section 600 and the injection molding machine 1.

[0066] The polymer return unit 1000 returns at least a portion of the polymer synthesized in the polymerization reactor 400 (in the example shown, the polymer for which byproducts have been further removed by the byproduct removal device 500) to the polymerization reactor 400 and / or the depolymerization reactor 300 instead of conveying it to the polymer supply unit 600. For example, the polymer return unit 1000 may supply polymer to a buffer tank 370 located at the front of the polymerization reactor 400 in order to return polymer to the polymerization reactor 400, or it may supply polymer to a polymer conditioning device 200 located at the front of the depolymerization reactor 300 in order to return polymer to the depolymerization reactor 300.

[0067] The main purpose of the polymer return unit 1000 is to address the mismatch in operating time and capacity between the chemical recovery unit 100 and the injection molding machine 1. For example, the chemical recovery unit 100 typically operates continuously, while the injection molding machine 1 typically operates intermittently. Therefore, especially during periods when the injection molding machine 1 is stopped due to maintenance of molds, etc., it cannot receive the full amount of polymer from the polymer supply unit 600 (unacceptable period). Even during such unacceptable periods, the remaining polymer that the injection molding machine 1 cannot accept is not wasted, and it can be returned in a molten state to the polymerization reaction tank 400 and / or the depolymerization reaction tank 300 so that the chemical recovery unit 100 can continue to operate continuously. In this way, since it is not necessary to process the remaining polymer in a molten state that the injection molding machine 1 cannot accept into fragments or granules through cooling and heat dissipation, energy waste can be reduced.

[0068] The polymer return unit 1000 can change the return destination (polymerization reactor 400 and / or depolymerization reactor 300) and return ratio of the remaining polymer according to the length of the unacceptable period. For example, before the unacceptable period exceeds a predetermined period threshold, more polymer than the depolymerization reactor 300 can be returned to the polymerization reactor 400, and after the unacceptable period exceeds the period threshold, more polymer than the polymerization reactor 400 can be returned to the depolymerization reactor 300.

[0069] It can be assumed that as long as the unacceptable period is short and does not exceed the period threshold, even if the molten polymer is circulated in the polymerization reactor 400 (and by-product removal device 500) at a high temperature (e.g., between 270°C and 280°C as described above), polymer degradation or excessive increase in IV value will not occur. Therefore, for shorter unacceptable periods, it is preferable that the polymer return section 1000 returns most of the remaining polymer (e.g., 100%, 80%, 60%) to the polymerization reactor 400 (buffer tank 370).

[0070] On the other hand, if the unacceptable period exceeds the period threshold and becomes a long period, the polymer in the molten state will generate a thermal history by circulating in the polymerization reactor 400 (and by-product removal device 500) at a high temperature (e.g., between 270°C and 280°C as described above), which may lead to polymer deterioration or an excessive increase in the IV value. Therefore, for a long unacceptable period, it is preferable that the polymer return unit 1000 returns most of the remaining polymer (e.g., 100%, 80%, 60%) to the depolymerization reactor 300 (polymer adjustment device 200). By performing the depolymerization reaction again in the depolymerization reactor 300, the aforementioned thermal history is essentially reset, thus effectively preventing the deterioration of the polymer supplied by the polymer supply unit 600 to the injection molding machine 1 after the unacceptable period.

[0071] In this modified example, since the temperature of the molten polymer in the cycle is approximately constant (e.g., between 270°C and 280°C as described above), the length of the period cannot be used to represent the thermal history. On the other hand, when the temperature of the molten polymer in the cycle may vary significantly, the thermal history can be strictly controlled by monitoring the temperature in addition to the unacceptable length of the period. In this case, the polymer return unit 1000 can return more polymer than the depolymerization reaction tank 300 to the polymerization reaction tank 400 before the thermal history exceeds a predetermined thermal history threshold, and return more polymer than the polymerization reaction tank 400 to the depolymerization reaction tank 300 after the thermal history exceeds the thermal history threshold.

[0072] Furthermore, the polymer return unit 1000 can change the return destination (polymerization reactor 400 and / or depolymerization reactor 300) and return ratio based on physical parameters such as the IV value of the polymer being returned. For example, if the IV value is within a predetermined allowable range, more polymer than the depolymerization reactor 300 can be returned to the polymerization reactor 400; if the IV value is outside the allowable range (specifically, greater than the upper limit of the allowable range), more polymer than the polymerization reactor 400 can be returned to the depolymerization reactor 300. In the latter case, by performing a depolymerization reaction again in the depolymerization reactor 300, the excessively high IV value is reduced to within the allowable range.

[0073] Furthermore, the polymer return unit 1000 can gradually change the return ratio to the polymerization reactor 400 and the depolymerization reactor 300 based on physical parameters such as the length of the unacceptable period and the IV value of the polymer to be returned. For example, the proportion of return to the depolymerization reactor 300 can be gradually increased as the unacceptable period lengthens, or the proportion of return to the depolymerization reactor 300 can be gradually increased as the IV value increases.

[0074] Figure 5 A second embodiment of the recycling system according to the present invention is schematically illustrated. (Regarding...) Figure 1 The same components as those in the first embodiment are labeled with the same reference numerals, and descriptions of the same general meaning are omitted. Furthermore, in Figure 5 In the same figures thereafter, for convenience, the components of the recycling system are shown as functional modules.

[0075] The recycling system according to the second embodiment includes a quality determination unit 710, a material sorting unit 720, a chemical recycling device 100, and a mechanical recycling device 900. The chemical recycling device 100 and... Figure 1 The first embodiment is constructed in the same way, but... Figure 5 The polymer adjustment device 200 is omitted from the text. Figure 5 In the example, in addition to the polymer adjustment device 200, a quality determination unit 710 and a material sorting unit 720 are also provided, or, in place of the polymer adjustment device 200, a quality determination unit 710 and a material sorting unit 720 are provided.

[0076] The mechanical recycling unit 900 performs mechanical recycling of solid materials such as PET fragments (specifically, high-quality materials described later). The mechanical recycling unit 900 can be configured as a completely independent device from the chemical recycling unit 100, but... Figure 5In the example, the polymerization accelerator 500 and / or polymer supply section 600 of the final section of the chemical recycling unit 100 can also be shared in the mechanical recycling unit 900. In such a mechanical recycling unit 900, solid materials (high-quality materials) such as PET fragments are heated and melted by a heater 910, and polymers such as PET with the desired degree of polymerization or IV value are obtained through polymerization reactions in the polymerization accelerator 500 and / or polymer supply section 600.

[0077] The heater 910 of the mechanical recycling device 900 can be configured in the same way as the buffer tank 430 and the second preheater 431 of the chemical recycling device 100. That is, similar to the second preheater 431, the heater 910 heats and melts the high-quality material containing polymers such as PET before it is supplied to the downstream polymerization accelerator 500 and / or polymer supply section 600. The heater 910 can heat the high-quality material to the same temperature (between 250°C and 300°C) as the heater 410 of the polymerization reaction tank 400 attached to the chemical recycling device 100, or to the same temperature suitable for polymerization reaction (between 250°C and 290°C) as the heater 520 attached to the polymerization accelerator 500, or to the same temperature (between 250°C and 290°C) as the heater 620 attached to the polymer supply section 600. Furthermore, similar to the buffer tank 430, the heater 910 can temporarily store high-quality materials such as molten PET before supplying them to the downstream polymerization accelerator 500 and / or polymer supply unit 600.

[0078] Thus, by placing a heater 910 with both heating and storage functions in front of the polymerization accelerator 500 and / or the polymer supply unit 600, polymers (such as PET derived from high-quality materials) awaiting delivery to the polymerization accelerator 500 and / or the polymer supply unit 600 can be stored at a suitable temperature. As a result, the capacity of the mechanical recycling unit 900 or the recycling system as a whole can be increased, and the mechanical recycling unit 900 or the recycling system as a whole can operate stably and continuously.

[0079] The polymer supply unit 600 is shared in both the mechanical recycling unit 900 and the chemical recycling unit 100. Figure 5 In the example, PET and other high-quality materials that have undergone mechanical recycling in the mechanical recycling unit 900 and PET and other low-quality materials that have undergone chemical recycling in the chemical recycling unit 100 are supplied to the injection molding machine 1 in a mixed state.

[0080] The quality determination unit 710 determines the quality of solid materials such as PET fragments according to a predetermined quality determination standard. The material sorting unit 720 sorts the solid materials such as PET fragments into high-quality materials (those determined by the quality determination unit 710 to be of higher quality than the quality determination standard) and low-quality materials (those determined by the quality determination unit 710 to be of lower quality than the quality determination standard). The quality determination unit 710 and the material sorting unit 720 can be constructed separately, but it is preferable that they are configured as follows: Figure 6 As illustrated in the diagram, it is generally constructed as a single unit.

[0081] exist Figure 6 In this process, PET fragments, which are solid materials, are fed from the supply port at the upper left. These PET fragments can include high-quality materials (shown schematically as solid circles) whose quality exceeds the quality judgment criteria in the quality judgment section 710, and low-quality materials (shown schematically as dashed circles) whose quality falls below the criteria. For example, when the PET fragments originate from a PET bottle, PET fragments located near the outer circumferential surface of the PET bottle may deteriorate due to external light, water, etc., while PET fragments located near the inner circumferential surface of the PET bottle may adsorb limonene or other substances contained in the contents. These PET fragments can be classified as low-quality materials. On the other hand, PET fragments located far from both the outer and inner circumferential surfaces of the PET bottle, or PET fragments that are not deteriorated or contaminated on either the outer or inner circumferential surfaces, can be classified as high-quality materials.

[0082] Thus, solid materials such as PET fragments, which are a mixture of low-quality and high-quality materials, are transported from one end of conveyor belt 721. Figure 6 The left end of the middle is transmitted to the other end ( Figure 6 The sensor 711 measures each PET fragment falling from the other end of the conveyor belt 721 in a non-contact manner. This non-contact measurement method is arbitrary and can utilize electricity, magnetism, heat, etc., but light and / or electromagnetic waves are preferred. The sensor 711 then optically measures each PET fragment falling from the other end of the conveyor belt 721. Specifically, the sensor 711 acquires light from each PET fragment or an image of each PET fragment. The sensor 711 can also measure natural light or ambient light reflected by each PET fragment, or it can measure light of any wavelength emitted by the sensor 711 itself reflected by each PET fragment.

[0083] In the PET fragment group continuously measured by sensor 711, various properties such as optical characteristics (e.g., color) of low-quality materials change as their quality deteriorates. Therefore, a significant difference arises in the measured values ​​by sensor 711 between low-quality and high-quality materials. Thus, the quality determination unit 710 applies an appropriate quality determination criterion or threshold to the measured values ​​of sensor 711, thereby enabling it to classify the PET fragment group as high-quality or low-quality materials. Furthermore, the material sorting unit 720 sorts the PET fragment group into high-quality and low-quality materials based on the judgment result of the quality determination unit 710. Figure 6 In the example, the material sorting unit 720, which is implemented by the air nozzle, sprays air only on PET fragments that are determined to be low-quality materials by the quality determination unit 710 (conversely, it can also spray air only on PET fragments that are determined to be high-quality materials by the quality determination unit 710), thereby sorting or separating them from high-quality materials.

[0084] As described above, through the action of the quality judgment unit 710 and the material sorting unit 720, the material is supplied to Figure 5 The recycling system shown separates PET fragments into high-quality and low-quality materials in a solid state. For example... Figure 5 As shown, high-quality solid materials sorted by the material sorting unit 720 are supplied to the mechanical recycling unit 900 for mechanical recycling. Conversely, low-quality solid materials sorted by the material sorting unit 720 are supplied to the chemical recycling unit 100 for chemical recycling. Furthermore, the high-quality and / or low-quality materials sorted by the material sorting unit 720 can be directly fed into the mechanical recycling unit 900 and / or the chemical recycling unit 100, or they can be temporarily stored before being fed into the mechanical recycling unit 900 and / or the chemical recycling unit 100.

[0085] In this embodiment, solid materials such as PET fragments are sorted into high-quality materials and low-quality materials according to quality judgment criteria. High-quality materials are efficiently recovered through mechanical recycling treatment (mechanical recycling device 900), which has a low quality improvement effect but is simple to operate. Low-quality materials are recovered while their quality is improved through chemical recycling treatment (chemical recycling device 100), which has a high quality improvement effect. Thus, according to this embodiment, by applying appropriate recycling treatment (mechanical recycling treatment or chemical recycling treatment) corresponding to the quality of solid materials such as PET fragments, the quality of the recycled products can be stabilized.

[0086] Furthermore, according to this embodiment, the high-quality materials sorted by the material sorting unit 720 are allocated to the mechanical recycling device 900, thus reducing the burden on the chemical recycling device 100. Therefore, the size of the chemical recycling device 100, which is typically more complex and expensive than the mechanical recycling device 900, can be reduced. Moreover, the high-quality materials sorted by the material sorting unit 720 are rapidly and efficiently recycled by the mechanical recycling device 900, which has a simpler structure and lower operating costs compared to the chemical recycling device 100, thus significantly improving the overall throughput and effectiveness of the recycling system.

[0087] Furthermore, the recycling system according to this embodiment includes both a mechanical recycling device 900 for high-quality materials and a chemical recycling device 100 for low-quality materials, thus enabling it to accept solid materials such as PET fragments with unstable quality. Therefore, according to this embodiment, a highly versatile recycling system capable of handling a wide range of solid materials can be provided.

[0088] Figure 7 A third embodiment of the recycling system according to the present invention is schematically shown. The same reference numerals are used to denote the same components as in the above embodiments, and descriptions of the same general meaning are omitted. The recycling system according to the third embodiment includes a partial depolymerization unit 730, a solid-liquid separation unit 740, a degraded material recycling unit 750, and a chemical recycling device 100. The chemical recycling device 100 and... Figure 1 The first embodiment is constructed in the same way, but... Figure 7 The polymer adjustment device 200 is omitted from the text. Figure 7 In the example, a partial depolymerization unit 730, a solid-liquid separation unit 740, and a degraded material recovery unit 750 are provided instead of the polymer conditioning device 200; or, in addition to the polymer conditioning device 200, a partial depolymerization unit 730, a solid-liquid separation unit 740, and a degraded material recovery unit 750 are provided.

[0089] The partial depolymerization unit 730 partially decomposes solid materials such as PET fragments into depolymerized products through a depolymerization reaction. When the polymer to be recycled contained in the solid material is PET, according to... Figure 2The depolymerization reaction (300) shown decomposes PET using EG as the depolymerization material, thereby obtaining BHET as the depolymerized product. This depolymerization reaction is essentially the same as the depolymerization reaction produced in the depolymerization reaction tank 300 in the chemical recycling device 100, but in the partial depolymerization section 730, only the surface portion of solid materials such as PET fragments is decomposed by the depolymerization reaction. As mentioned above, for example, PET fragments originating from PET bottles may have their surface quality deteriorated due to the influence of light, water, etc. from outside the PET bottle, or the adsorption of limonene and other substances contained in the contents of the PET bottle. The main purpose of the partial depolymerization section 730 is to decompose the surface portion of solid materials such as PET fragments, whose quality may be deteriorated, through the depolymerization reaction.

[0090] The solid-liquid separation unit 740 separates the solid and liquid components obtained in the partial depolymerization unit 730. In the case of PET fragments as solid material, the solid component includes high-quality PET fragments or high-quality PET particles remaining from BHET that did not decompose into a liquid state in the partial depolymerization unit 730. The liquid component includes BHET generated from the depolymerization reaction of the surface portion of the PET fragments, particles from the surface portion of degraded PET fragments, unreacted EG, contaminants related to the quality degradation of the surface portion of the PET fragments, and a mixture of cleaning fluids such as water. The solid component, as a high-quality solid material, is supplied to the chemical recovery unit 100 for chemical recovery treatment. Liquid components that may contain contaminants and are unsuitable for recovery are recovered in the degraded material recovery unit 750.

[0091] Furthermore, the solid-liquid separation unit 740 according to this embodiment does not need to completely separate the solid and liquid. For example, as described later... Figures 8-11 In the solid-liquid separation section 740 specifically illustrated, high-quality PET fragments or high-quality PET particles, as solids, are extracted from the solid component extraction section 850 at the bottom in the form of a slurry or the like mixed with liquid. Thus, the solid component separated by the solid-liquid separation section 740 can contain any form of solid, such as high-quality PET fragments or high-quality PET particles, and may include liquid that forms a slurry or the like together with the solid. In other words, the solid component in this embodiment can contain any form of solid (typically, solid particles) derived from a solid material, regardless of the presence or absence of liquid.

[0092] In this embodiment, surfaces and other easily deteriorated areas in solid materials such as PET fragments are partially decomposed, while relatively high-quality solid components are separated. Thus, by chemically recycling the high-quality solid components, the quality of the recycled products can be stabilized.

[0093] Furthermore, the recycling system according to this embodiment, through the partial depolymerization section 730 and the solid-liquid separation section 740, can effectively remove surface portions that are prone to quality deterioration, and therefore can also accept low-quality PET fragments and other fixation materials. Thus, according to this embodiment, a highly versatile recycling system capable of handling a wide range of fixation materials can be provided.

[0094] Furthermore, the partial depolymerization section 730 and the solid-liquid separation section 740 can be constructed separately, but it is preferable to construct them as follows: Figure 8 It is roughly integrally constructed as illustrated in the diagram. Figure 8 In the middle, the partial depolymerization section 730 and the solid-liquid separation section 740 are composed of a partial depolymerization reaction tank 810, a solid material supply section 820, a depolymerization material supply section 830, a depolymerization product discharge section 840, and a solid component extraction section 850.

[0095] In the partial depolymerization reaction tank 810, a partial depolymerization reaction occurs with respect to the solid materials such as PET fragments mentioned above in the partial depolymerization section 730. The solid material supply section 820 supplies solid materials such as PET fragments into the partial depolymerization reaction tank 810. The depolymerization material supply section 830 supplies depolymerization materials such as EG, used for decomposing polymers such as PET, into the partial depolymerization reaction tank 810. As described later, the depolymerization material supply section 830 can supply cleaning fluid (such as high-quality PET) remaining after the depolymerization reaction to the partial depolymerization reaction tank 810. The depolymerization product discharge section 840 discharges liquid depolymerization products such as BHET generated by the depolymerization reaction. As described later, the depolymerization product discharge section 840 is not limited to depolymerization products such as BHET; it can also discharge any liquid component from the partial depolymerization reaction tank 810, such as the aforementioned cleaning fluid. The solid component removal section 850 removes the solid components (such as high-quality PET) remaining after the depolymerization reaction.

[0096] Figure 8The structure achieves the functions of the partial depolymerization unit 730 and the solid-liquid separation unit 740 in the following sequence. First, as a first step, the solid material supply unit 820 supplies solid materials such as PET fragments into the partial depolymerization reaction tank 810, and the depolymerization material supply unit 830 supplies depolymerization materials such as EG into the partial depolymerization reaction tank 810. At this time, the partial depolymerization reaction tank 810 is maintained at the same temperature (e.g., between 220°C and 250°C, preferably between 230°C and 245°C, and more preferably between 235°C and 240°C) and pressure (e.g., between 0.3 MPa and 0.8 MPa, preferably between 0.4 MPa and 0.6 MPa, and more preferably between 0.45 MPa and 0.55 MPa) as the depolymerization reaction tank 300. Therefore, in the partial depolymerization reaction tank 810, the surface portion of solid materials such as PET fragments supplied by the solid material supply unit 820 produces a depolymerization reaction that is substantially the same as that produced in the depolymerization reaction tank 300.

[0097] The depolymerization material supply unit 830 can supply depolymerization materials such as EG in liquid form (e.g., aqueous solution) into the partial depolymerization reaction tank 810, but preferably supplies vapor of depolymerization materials such as EG into the partial depolymerization reaction tank 810. For example, as Figure 8 The diagram schematically illustrates that the depolymerization material supply unit 830, located in the roof of the partial depolymerization reaction tank 810, can inject or spray EG vapor into the partial depolymerization reaction tank 810. Advantages of supplying depolymerization materials such as EG in the form of steam include: reducing the impact of phase transitions across boiling points, enabling stable and rapid depolymerization reactions at high temperatures; increasing the reaction temperature, reducing the need for catalysts other than EG, and in extreme cases, allowing surface depolymerization reactions to occur without a catalyst.

[0098] After the depolymerization reaction of the surface portion of solid materials such as PET fragments is fully carried out in the partial depolymerization reaction tank 810 (i.e., after the first step) or during the depolymerization reaction (i.e., simultaneously with the first step), as a second step, a liquid component containing depolymerized materials such as BHET generated by the depolymerization reaction, particles of the surface portion of solid materials such as deteriorated PET fragments, unreacted depolymerized materials such as EG, and pollutants related to the quality deterioration of the surface portion of solid materials such as PET fragments is discharged from the depolymerization discharge section 840 provided at the bottom of the partial depolymerization reaction tank 810. The depolymerization discharge section 840 is composed of a filter and a valve capable of continuously or intermittently discharging the liquid component.

[0099] After the surface portion of solid materials such as PET fragments has been sufficiently depolymerized in the partial depolymerization reaction tank 810, as a third step after the first step, a depolymerization material supply unit 830 provided in the top of the partial depolymerization reaction tank 810 supplies cleaning fluid to the partial depolymerization reaction tank 810 to clean the solid components remaining after the depolymerization reaction (high-quality PET fragments, etc., with degraded surface portions removed). Examples of cleaning fluids include water and liquid EG (e.g., aqueous solution), which is also used as a depolymerization material. At this time, as a fourth step after the third step, the cleaning fluid is discharged from the depolymerization product discharge unit 840 provided at the bottom of the partial depolymerization reaction tank 810. Here, the second and fourth steps of discharging liquid components from the depolymerization product discharge unit 840 can also be performed simultaneously.

[0100] After steps 1 through 4 are completed, the high-quality PET fragments, which were degraded in steps 1 and 2 and were cleaned in steps 3 and 4, are deposited as solid components at the bottom of the partial depolymerization reaction tank 810. In the final step 5, the solid component containing such high-quality PET fragments is removed from the solid component removal section 850 located at the bottom of the partial depolymerization reaction tank 810.

[0101] Steps 1 through 5 described above can be repeated for each processing unit or batch of solid material that is the object of processing, involving partial depolymerization (or surface depolymerization) based on the partial depolymerization unit 730 and solid-liquid separation based on the solid-liquid separation unit 740. Furthermore, multiple such... Figure 8 The processing device shown can process even large quantities of solid materials in parallel at high speed.

[0102] Alternatively, you can use settings such as Figure 8 The dedicated processing apparatus shown allows the depolymerization reaction tank 300, which also generates the depolymerization reaction, to function as a partial depolymerization section 730 and a solid-liquid separation section 740. For example, when PET fragments are first supplied, the depolymerization reaction tank 300 functions as a partial depolymerization section 730 and a solid-liquid separation section 740, extracting the solid components composed of high-quality PET fragments through a surface depolymerization reaction (the liquid components are separated and recovered in the degraded material recovery section 750). Then, the depolymerization reaction tank 300 functions as its original depolymerization reaction tank 300, decomposing the entire amount of the solid components (high-quality PET fragments) into BHET as depolymerized products through a depolymerization reaction.

[0103] Figures 9-11 schematically shown Figure 8 A modified example of the processing apparatus shown. For Figures 8-11The same constituent elements are labeled with the same reference numerals in the accompanying drawings, and the same descriptions are omitted.

[0104] exist Figure 9 In a modified example, the partial depolymerization section 730 and the solid-liquid separation section 740 are composed of a partial depolymerization reaction tank 810, a solid material supply section 820, a depolymerization material supply section 830, a depolymerization product discharge section 840, a solid component extraction section 850, and a partition plate 860.

[0105] A depolymerization material supply unit 830, which supplies depolymerization materials such as EG and / or cleaning fluid to a partial depolymerization reaction tank 810, is provided in a location not limited to, such as... Figure 8 Any part of the inner wall surface of the partially depolymerization reaction tank 810 shown in the diagram (e.g., including the sides and bottom). The partition 860 dividing the partially depolymerization reaction tank 810 vertically has holes through which at least a portion of the solid material such as PET fragments before the depolymerization reaction cannot pass. Such a partition 860 is, for example, made of a mesh of metal such as stainless steel, a mesh with holes smaller than those of ordinary PET fragments, or a plate. At least one of the solid material supply section 820 and the depolymerization material supply section 830 may be provided at a position higher than the partition 860, and at least one of the depolymerization material supply sections 830, the depolymerization discharge section 840, and the solid component extraction section 850 may be provided at a position lower than the partition 860.

[0106] like Figure 9 The diagram schematically shows PET fragments concentrated on the separator 860 before the depolymerization reaction. Then, multiple depolymerization material supply units 830 spray depolymerization materials such as EG onto the PET fragments concentrated on the separator 860 from various directions, thereby efficiently decomposing the surface portion of the PET fragments through the depolymerization reaction. The liquid depolymerized material such as BHET generated by the depolymerization reaction passes downward through the holes in the separator 860 and is discharged from the depolymerized material discharge unit 840. Furthermore, cleaning liquid supplied from at least one of the multiple depolymerization material supply units 830 also passes downward through the holes in the separator 860 and is discharged from the depolymerized material discharge unit 840. Finally, high-quality solid components such as PET fragments, which have become smaller due to the surface depolymerization reaction, pass downward through the holes in the separator 860 and are removed from the solid component removal unit 850.

[0107] exist Figure 10 In a modified example, the partial depolymerization section 730 and the solid-liquid separation section 740 are composed of a partial depolymerization reaction tank 810, a solid material supply section 820, a depolymerization material supply section 830, a depolymerization product discharge section 840, a solid component extraction section 850, and a stirring blade 870.

[0108] In this modified example, the depolymerization material supply unit 830 is located at the bottom of the partial depolymerization reaction tank 810, and the depolymerization product discharge unit 840 is located at the top of the partial depolymerization reaction tank 810 (or, at a position higher than the solid component extraction unit 850). Liquid depolymerization materials such as EG, catalysts, and / or liquid depolymerization products such as BHET generated through the partial depolymerization reaction, supplied from the depolymerization material supply unit 830, fill the partial depolymerization reaction tank 810 from the bottom up to the position where the depolymerization product discharge unit 840 is located. Thus, the liquid level in the partial depolymerization reaction tank 810 is formed at the position where the depolymerization product discharge unit 840 is located. Excess liquid components are discharged from the depolymerization product discharge unit 840, which consists of a filter and a valve. Alternatively, multiple depolymerization product discharge units 840 may be provided at different heights. At this time, the depolymer discharge section 840, which is located at the highest position, serves to prevent overflow and form a partial liquid surface in the depolymerization reaction tank 810, while the depolymer discharge section 840, which is located at a lower position, discharges depolymers such as BHET from the middle height position.

[0109] The stirring blades 870 are particularly effective in agitating solid materials such as PET fragments and depolymerizing materials such as EG, which are reactants, during the depolymerization reaction. This agitation not only ensures the efficient conduction of the depolymerization reaction but also refines the residual solid components (such as high-quality PET) remaining on the surface after the depolymerization reaction. These refined solid components can then pass through the solid component extraction section 850, which consists of a filter and a valve, and are thus removed from the partial depolymerization reaction tank 810.

[0110] The series of processes described above can be used as a basis for... Figure 8 , Figure 9 The same batch processing can be performed, or it can be performed as continuous processing. In continuous processing, while the stirring blade 870 is continuously rotating in the partial depolymerization reaction tank 810, at least one of the following is performed continuously or intermittently: supplying solid material from the solid material supply section 820, supplying depolymerization material from the depolymerization material supply section 830, discharging depolymerization material from the depolymerization discharge section 840, and removing solid components from the solid component removal section 850.

[0111] exist Figure 11 In a modified example, the partial depolymerization section 730 and the solid-liquid separation section 740 are composed of a partial depolymerization reaction tank 810, a solid material supply section 820, a depolymerization material supply section 830, a depolymerization product discharge section 840, a solid component extraction section 850, a stirring blade 870, and a baffle 880.

[0112] In this modified example, the solid components (such as high-quality PET) remaining after the depolymerization reaction of the surface portion of solid materials such as PET fragments are efficiently miniaturized by colliding with the baffle 880, also known as the baffle plate, when stirred by the stirring blade 870.

[0113] Figure 12 schematically shown Figure 7 The structure of the recycling system involved in the modified example. For... Figure 7 The same components are labeled with the same reference numerals, and repeated descriptions are omitted. In this modified example, a mechanical mixing section 760 is provided in the partial depolymerization section 730. In at least the early stage of the depolymerization reaction in which the polymer is decomposed into depolymers by the depolymerization material, the mechanical mixing section 760 mechanically or physically mixes the depolymerization material and the polymer.

[0114] like Figure 2 As shown, the depolymerization reaction that breaks down polymers such as PET into depolymers such as BHET using depolymerizing materials such as EG is essentially a chemical process. However, as Figure 13 The diagram illustrates that in the early or early stages of depolymerization reactions with high degrees of polymerization, polymers such as PET sometimes exist in large pieces, such as fragments or particles, where mechanical actions such as stirring and mixing dominate over chemical actions (chemical reactions). On the other hand, in the later stages of depolymerization reactions, the desired chemical actions (chemical reactions) become dominant.

[0115] The mechanical mixing section 760 involved in this modification, particularly in the early or pre-stage of the depolymerization reaction where mechanical action predominates, efficiently mixes depolymerizing materials such as EG and polymers such as PET by mechanically mixing them during this period, thereby enabling a rapid transition to the later stage where chemical action (chemical reaction) predominates (mainly in the depolymerization reaction tank 300, which is further downstream than the partial depolymerization section 730). As a result, the depolymerization reactions in the partial depolymerization section 730 and the depolymerization reaction tank 300 can be carried out efficiently in a short time. The mechanical mixing section 760 can continue mechanically mixing depolymerizing materials such as EG and polymers such as PET not only in the early or pre-stage of the depolymerization reaction where mechanical action predominates, but also in the later stage of the depolymerization reaction where chemical action (chemical reaction) predominates (when carried out in the partial depolymerization section 730). Furthermore, similar to the polymer conditioning device 200 described above, the mechanical mixing section 760 can perform processes such as crushing, heating and melting, and mixing. Therefore, the polymer conditioning device 200 can be omitted, or it can be integrated into the mechanical mixing section 760.

[0116] The aforementioned mechanical mixing unit 760 can be attached to or externally mounted to, for example... Figures 8-11 The partial depolymerization section 730 (and solid-liquid separation section 740) of the single-tank structure shown. For example, the ultrasonic device described later as a mechanical mixing section 760 can be installed on the outer wall and / or inner wall of the partial depolymerization section 730, or the cavitation device described later as a mechanical mixing section 760 can be provided at the front of the partial depolymerization section 730.

[0117] The aforementioned mechanical mixing unit 760 can be configured in any manner, as long as it can achieve the function of mechanically mixing depolymerizing materials such as EG and polymers such as PET, especially in the early stages of the depolymerization reaction. Hereinafter, using... Figure 10 Taking the partially depolymerized section 730 and the solid-liquid separation section 740 shown as examples, several non-limiting embodiments of the mechanical mixing section 760 that can be disposed therein are listed.

[0118] Figure 14 A first embodiment of the mechanical mixing unit 760 is schematically shown. This embodiment is... Figure 10 The structure of the ultrasonic device 761, which is a mechanical mixing unit 760, is added to the partial depolymerization section 730 and the solid-liquid separation section 740 shown in the first embodiment.

[0119] In the partial depolymerization reaction tank 810, partial depolymerization of polymers such as PET fragments is carried out, especially regarding... Figure 13 The aforementioned initial or preliminary mechanical mixing with depolymerizing materials such as EG. The polymer supply unit 820 supplies polymers such as PET fragments into the partial depolymerization reaction tank 810. The depolymerizing material supply unit 830, located at the bottom of the partial depolymerization reaction tank 810, supplies depolymerizing materials such as EG for decomposing polymers such as PET into the partial depolymerization reaction tank 810. The depolymerization product discharge unit 840, located at the top of the partial depolymerization reaction tank 810, discharges liquid depolymerized products such as BHET generated through the depolymerization reaction. The polymer extraction unit 850 removes the PET slurry and other residues remaining after the depolymerization reaction. The PET slurry and other residues removed from the polymer extraction unit 850 are transported to the subsequent depolymerization reaction tank 300 for further depolymerization reaction (especially regarding...). Figure 13 The aforementioned later-stage desired chemical reaction is decomposed into depolymers such as BHET.

[0120] The stirring blades 870 and / or the ultrasonic device 761 mechanically mix or stir the polymers such as PET supplied from the polymer supply section 820 and the depolymerization materials such as EG supplied from the depolymerization material supply section 830 within the partial depolymerization reaction tank 810, thereby promoting the initial or early stage of the depolymerization reaction undertaken by the partial depolymerization section 730. Through such mechanical mixing, not only is the depolymerization reaction carried out efficiently, but PET fragments are also fined into a slurry. The fined PET slurry can then pass through the polymer extraction section 850, which consists of a filter and a valve, and is thus extracted from the partial depolymerization reaction tank 810 and transported to the depolymerization reaction tank 300.

[0121] The ultrasonic device 761 is installed continuously (e.g., in a ring) or intermittently at any location on the outer and / or inner wall of the partial depolymerization reaction tank 810. The ultrasonic waves (vibrations) generated by the ultrasonic device 761 mechanically mix polymers such as PET and depolymerized materials such as EG within the partial depolymerization reaction tank 810. Alternatively, if it is difficult to install the ultrasonic device 761 on the wall of the partial depolymerization reaction tank 810, another ultrasonic tank equipped with the ultrasonic device 761 can be connected to the partial depolymerization reaction tank 810. In this case, mechanical mixing based on the ultrasonic device 761 occurs within the ultrasonic tank, and micronized PET and the like are removed from the polymer extraction section 850 of the partial depolymerization reaction tank 810.

[0122] according to Figure 14 The structure allows the ultrasonic waves generated by the ultrasonic device 761 to mechanically mix polymers such as PET fragments supplied by the polymer supply unit 820 and depolymerizing materials such as EG supplied by the depolymerizing material supply unit 830. Furthermore, in cases where the PET fragments are too large, stirring based on the contact stirring blades 870 is difficult; however, with the non-contact ultrasonic device 761, mixing can be effectively performed regardless of the size of the PET fragments.

[0123] After the polymers such as PET fragments have been sufficiently mechanically mixed in the partial depolymerization reaction tank 810, or during the mechanical mixing process, the depolymerization liquid, including depolymers such as BHET generated by the depolymerization reaction, is discharged from the depolymerization discharge section 840 located at the top of the partial depolymerization reaction tank 810. The depolymerization discharge section 840 is composed of a filter and a valve capable of continuously or intermittently discharging liquid components. Liquid depolymerization materials such as EG, catalysts, and / or liquid depolymers such as BHET generated by the partial depolymerization reaction, supplied from the depolymerization material supply section 830, fill the partial depolymerization reaction tank 810 from the bottom up to the position where the depolymerization discharge section 840 is located. Thus, the liquid level in the partial depolymerization reaction tank 810 is formed at the position where the depolymerization discharge section 840 is located. Excess liquid components are discharged from the depolymerization discharge section 840, which is composed of a filter and a valve. In addition, multiple depolymerization discharge sections 840 may be provided at different heights. At this time, the depolymer discharge section 840, which is located at the highest position, serves to prevent overflow and form a partial liquid surface in the depolymerization reaction tank 810, while the depolymer discharge section 840, which is located at a lower position, discharges depolymers such as BHET from the middle height position.

[0124] After the polymer such as PET fragments and depolymerization materials such as EG are fully mechanically mixed in the partial depolymerization reaction tank 810, the micronized and deposited PET slurry is taken out from the polymer take-out section 850 located at the bottom of the partial depolymerization reaction tank 810.

[0125] The aforementioned steps can be performed continuously (continuous processing) by continuously supplying polymers such as PET fragments to the polymer supply unit 820 and depolymerizing materials such as EG to the depolymerizing material supply unit 830, or they can be performed according to a predetermined processing unit or batch of polymers such as PET fragments and depolymerizing materials such as EG (batch processing). For example, in continuous processing, while the ultrasonic device 761 continuously emits ultrasonic waves and / or the stirring blade 870 continuously rotates in the partial depolymerization reaction tank 810, at least one of the following can be performed continuously or intermittently: supplying polymers (PET fragments, etc.) from the polymer supply unit 820, supplying depolymerizing materials from the depolymerizing material supply unit 830, discharging depolymerized material from the depolymerized material discharge unit 840, and removing polymers (PET slurry, etc.) from the polymer removal unit 850.

[0126] Figure 15 A second embodiment of the mechanical mixing unit 760 is schematically shown. This embodiment is... Figure 10 The structure of the cavitation device 762, which is a mechanical mixing unit 760, is added to the partially depolymerized section 730 and the solid-liquid separation section 740 shown in the second embodiment.

[0127] The stirring blades 870 and / or cavitation device 762 mechanically mix or stir polymers such as PET supplied from the polymer supply unit 820 and depolymerizing materials such as EG supplied from the depolymerizing material supply unit 830 within the partial depolymerization reaction tank 810, thereby promoting the initial or early stage of the depolymerization reaction undertaken by the partial depolymerization unit 730. Through such mechanical mixing, not only is the depolymerization reaction carried out efficiently, but PET fragments are also fined into a slurry. The fined PET slurry can then pass through the polymer extraction unit 850, which consists of a filter and a valve, and is thus extracted from the partial depolymerization reaction tank 810 and transported to the depolymerization reaction tank 300.

[0128] A cavitation device 762 is provided, for example, on the supply line from the depolymerization material supply unit 830 to the partial depolymerization reaction tank 810 for supplying depolymerization materials such as EG. The cavitation device 762 introduces a pressure difference into the liquid depolymerization material such as EG, thereby inducing cavitation (void phenomenon) accompanied by the generation and disappearance of bubbles. The typical microbubbles generated by cavitation mechanically mix the polymer such as PET and the depolymerization material such as EG within the partial depolymerization reaction tank 810. Alternatively, if it is difficult to install the cavitation device 762 in the first depolymerization reaction tank 301, another cavitation tank equipped with the cavitation device 762 can be connected to the partial depolymerization reaction tank 810. In this case, mechanical mixing based on the cavitation device 762 occurs within the cavitation tank, and finely processed PET is removed from the polymer extraction section 850 of the partial depolymerization reaction tank 810. Alternatively, a bubble generating device that generates microbubbles (also known as ultrafine bubbles or microbubbles) based on a different principle than cavitation can be used as the mechanical mixing unit 760 instead of the cavitation device 762. Or, in addition to the cavitation device 762, a bubble generating device that generates microbubbles based on a different principle than cavitation can also be used as the mechanical mixing unit 760.

[0129] according to Figure 15 The cavitation device 762, with its structure, generates microbubbles accompanying cavitation within the depolymerization material such as EG supplied by the depolymerization material supply unit 830 to the partial depolymerization reaction tank 810. These microbubbles, along with the depolymerization material such as EG, are introduced into the partial depolymerization reaction tank 810, mechanically mixing the polymer such as PET fragments supplied by the polymer supply unit 820 and the depolymerization material such as EG supplied by the depolymerization material supply unit 830. Furthermore, in cases where the PET fragments are too large, it is difficult to perform stirring based on the contact stirring blades 870; however, with the non-contact cavitation device 762, mixing can be effectively performed regardless of the size of the PET fragments.

[0130] Figure 16 A horizontal stirring device 763, as a third embodiment of the mechanical mixing unit 760, is schematically shown. The horizontal stirring device 763 is configured as follows: Figure 12 The partial depolymerization part 730 in the middle. Furthermore, Figure 12 The depolymerization reaction tank 300 in the middle is as follows Figure 1 or Figure 4 The vertical stirring device is shown. Here, "horizontal" refers to stirring by a rotating body that rotates about a rotation axis that intersects the vertical direction (e.g., the horizontal direction), and "vertical" refers to stirring by a rotating body (e.g., stirring blades) that rotates about a rotation axis that intersects the horizontal direction (e.g., the vertical direction).

[0131] exist Figure 16 (and the following) Figure 17For convenience, a three-dimensional coordinate system consisting of the X-axis, Y-axis, and Z-axis is set up in the diagram. For example, the X-axis and Y-axis are horizontal, and the Z-axis is vertical. In the example diagram, the horizontal stirring device 763 has its long dimension in the X-direction.

[0132] The horizontal stirring device 763 includes a container 1010, a rotating body 1020, and a rotation drive unit 1040.

[0133] For example, from Figure 1 , Figure 4 The polymer conditioning device 200 supplies polymer PM, such as PET, derived from the first molded article, to the container 1010 in a molten state. The container 1010 includes: a polymer supply port 1011 connected to the polymer conditioning device 200 to supply polymer PM into the container 1010; and a discharge port 1012 that discharges polymer PM (including unreacted depolymerized material and depolymerized products such as BHET) after being stirred (mechanically mixed) with depolymerizing materials such as EG by a rotating body 1020 (described later) out of the container 1010 and to a subsequent solid-liquid separation section 740 and / or depolymerization reaction tank 300. A transfer pump, such as a gear pump or screw pump, capable of adjusting the supply amount and speed of polymer PM into the container 1010 can be connected to the polymer supply port 1011, and a transfer pump, such as a gear pump or screw pump, capable of adjusting the discharge amount and speed of polymer PM, etc., out of the container 1010 can be connected to the discharge port 1012. Furthermore, a temperature control unit such as a heater can be installed in the container 1010 to maintain the appropriate temperature inside the container 1010 in order to maintain the molten state of the polymer PM.

[0134] like Figure 16 As illustrated, container 1010 is elongated in the X direction, for example having a generally rectangular YZ cross section (not shown). In the case where multiple rotating bodies 1020 are staggered along the Y direction, in order to accommodate these rotating bodies, the YZ cross section of container 1010 becomes elongated in the Y direction (i.e., rectangular).

[0135] exist Figure 16 In the container 1010, the polymer supply port 1011 is located at one end in the X direction. Figure 16 (Left end of the container), the outlet 1012 is located at the other end of the container 1010 in the X direction ( Figure 16(The right end of the container). In the X-direction region between the polymer supply port 1011 and the discharge port 1012, one or more gas supply ports 1013 are provided to deliver gases such as nitrogen to the gas phase inside the container 1010, and one or more depolymerization material supply ports 1014 are provided to supply depolymerization materials such as EG, which are mechanically mixed with polymer PM, to the gas phase inside the container 1010. Furthermore, in the X-direction region between the polymer supply port 1011 and the discharge port 1012, one or more rotating bodies 1020 are provided to stir (mechanically mix) the molten polymer PM supplied from the polymer supply port 1011 and the depolymerization materials such as EG supplied from the depolymerization material supply ports 1014.

[0136] The rotating body 1020 rotates within the container 1010 to agitate the polymer PM and the depolymerization material. The rotating body 1020 is positioned around a vertically oriented component (in... Figure 16 In the example, it's the Z direction) the direction of intersection (in Figure 16 In this example, one or more rotating plates 1021 rotate on a rotation axis 1022 (orthogonal to the Z direction in the X direction). The rotating plate 1021 is, for example, a circular plate with a circular YZ cross-section. However, the shape of the YZ cross-section of the rotating plate 1021 is arbitrary; for example, it can be an ellipse, triangle, or quadrilateral, etc. The center or centroid of the rotating plate 1021 in the YZ plane is preferably aligned with the center of the rotation axis 1022. In this case, one or more rotating plates 1021 and the rotation axis 1022 are arranged coaxially. Alternatively, the rotating body 1020 may have a screw instead of the rotating plate 1021, or it may have a screw in addition to the rotating plate 1021. When the rotating body 1020 has a screw, polymer PM such as PET can be supplied in a solid state.

[0137] exist Figure 16In the example, the rotating body 1020 has multiple rotating plates 1021 separated along the axial direction (X direction) of the rotation axis 1022. The axial distance between two adjacent rotating plates 1021 can be constant or different as shown in the figure. If the stirring of the polymer PM and the depolymerizing material progresses and a portion of it is decomposed into depolymers such as BHET, the viscosity or degree of polymerization of the polymer PM decreases. On the other hand, the closer to the inlet side of the container 1010 (i.e., the polymer supply port 1011 side), the higher the viscosity or degree of polymerization of the polymer PM, and therefore the easier it is for the polymer PM to adhere to the rotating plates 1021. If the spacing of the rotating plates 1021 on the inlet side of such container 1010 is too small, the polymer PM attached to each rotating plate 1021 may interfere with each other, hindering the stirring (mechanical mixing with the depolymerizing material) of the polymer PM and the rotation of the rotating body 1020. Therefore, as shown in the figure, it is preferable to reduce the spacing of the rotating plates 1021 from the polymer supply port 1011 (front section) of the container 1010 toward the discharge port 1012 (rear section).

[0138] Thus, in the later section (on the outlet 1012 side) where the intervals between the rotating plates 1021 are smaller, the polymer PM and the depolymerization material are efficiently stirred or mixed. Here, when multiple depolymerization material supply ports 1014 are provided, the efficiency of mechanical mixing of the polymer PM and the depolymerization material can be further improved by increasing the amount of depolymerization material supplied from each depolymerization material supply port 1014 from the front section to the rear section.

[0139] The rotating body 1020 is driven to rotate by a rotation drive unit 1040, which is composed of a motor or the like. Specifically, the rotation drive unit 1040 is connected to the rotation shaft 1022 of the rotating body 1020 and drives it to rotate. Thus, if the rotation shaft 1022 is driven to rotate by the rotation drive unit 1040, the plurality of rotating plates 1021 fixed thereon rotate as a whole. Then, the polymer PM supplied from the polymer supply port 1011 into the container 1010 and toward the discharge port 1012 is effectively mixed with the depolymerization material supplied from the depolymerization material supply port 1014 into the container 1010 by the rotating plurality of rotating plates 1021.

[0140] By stirring with the rotating body 1020, not only are the polymer PM and depolymerizing materials mechanically mixed, but also the decomposition (chemical reaction) of BHET and other polymers into depolymers occurs partially. As a result, the IV value, viscosity, and degree of polymerization of the polymer PM, such as PET, in the container 1010 gradually decrease as it moves from the polymer supply port 1011 toward the discharge port 1012. Furthermore, the position or height of the polymer PM attached to each rotating plate 1021 of the rotating body 1020 indirectly indicates the IV value, viscosity, and degree of polymerization of the polymer PM. Therefore, the IV value, viscosity, and degree of polymerization of the polymer PM can be determined by detecting the highest position of the polymer PM attached to the rotating plate 1021 in the vertical direction (Z direction) using an attachment position detection unit (not shown). For example, the attachment position detection unit can detect the highest position of the polymer PM attached to the rotating plate 1021 in the vertical direction (Z direction) using light traveling in a direction (Y direction) intersecting the vertical direction (Z direction) and the rotation axis 1022 (X direction).

[0141] The stirring mode adjustment unit (not shown) can adjust the stirring mode within container 1010 to reduce the deviation between the adhesion position (e.g., the highest reached position) of the polymer PM detected by the adhesion position detection unit and the desired position. The desired position at this time corresponds to the desired viscosity and degree of polymerization of the polymer PM within container 1010. In other words, the stirring mode adjustment unit can adjust the stirring mode within container 1010 to achieve the desired viscosity and degree of polymerization of the polymer PM within container 1010.

[0142] Specifically, as a stirring method within the container 1010, the stirring method adjustment unit can adjust at least one of the following: the supply amount of polymer PM and / or depolymerization material to the container 1010, the supply speed of polymer PM and / or depolymerization material to the container 1010, the discharge amount to the outside of the container 1010 through the discharge port 1012, the discharge speed to the outside of the container 1010 through the discharge port 1012, the rotational speed of the rotating body 1020, the pressure inside the container 1010, and the temperature inside the container 1010.

[0143] In addition to the adhesion location detection unit that indirectly detects the degree of polymerization of polymer PM, a degree of polymerization estimation unit (not shown) can also be provided to estimate the degree of polymerization of polymer PM based on the adhesion location of polymer PM detected by the adhesion location detection unit. At this time, the stirring mode adjustment unit adjusts the stirring mode in the container 1010 to reduce the deviation between the degree of polymerization of polymer PM estimated by the degree of polymerization estimation unit and the expected value.

[0144] Figure 17 A horizontal stirring device 764, as a fourth embodiment of the mechanical mixing unit 760, is schematically shown. (Regarding...) Figure 16The same components are labeled with the same reference numerals, and repeated descriptions are omitted. Horizontal stirring device 764 configuration. Figure 12 Partial depolymerization section 730. Figure 16 The horizontal stirring device 763 shown is a single-tank type; in contrast, Figure 17 The horizontal stirring device 764 shown is a multi-tank type (double-tank type in the example). Specifically, the horizontal stirring device 764 includes a first horizontal stirring device 764A on the front or upstream side and a second horizontal stirring device 764B on the rear or downstream side. In the example, both the first horizontal stirring device 764A and the second horizontal stirring device 764B are elongated in the X direction.

[0145] Both the first horizontal stirring device 764A and the second horizontal stirring device 764B are equipped with the aforementioned container 1010, rotating body 1020, and rotation drive unit 1040. The discharge port 1012 of the first horizontal stirring device 764A is connected to the polymer supply port 1011 of the second horizontal stirring device 764B.

[0146] The rotating body 1020 in the first horizontal stirring apparatus 764A and the second horizontal stirring apparatus 764B includes a plurality of rotating plates 1021 separated along the axial direction (X direction) of the rotating shaft 1022. The axial distance between adjacent rotating plates 1021 in the first horizontal stirring apparatus 764A is constant, and the axial distance between adjacent rotating plates 1021 in the second horizontal stirring apparatus 764B is constant. Here, the constant distance between adjacent rotating plates 1021 in the second horizontal stirring apparatus 764B is preferably set to be smaller than the constant distance between adjacent rotating plates 1021 in the first horizontal stirring apparatus 764A. In the second horizontal stirring apparatus 764B, after the mixing of the polymer PM and the depolymerization material (and the decomposition of depolymers such as BHET) has been performed, since the viscosity or degree of polymerization of the polymer PM has decreased, the distance between the rotating plates 1021 can be set to be smaller than that in the first horizontal stirring apparatus 764A.

[0147] Thus, in the second horizontal stirring device 764B, where the spacing of the rotating plates 1021 is relatively small, the polymer PM and the depolymerizing material are efficiently stirred or mixed. Furthermore, by increasing the amount of depolymerizing material supplied from the depolymerizing material supply port 1014 in the second horizontal stirring device 764B to be greater than the amount supplied from the depolymerizing material supply port 1014 in the first horizontal stirring device 764A, the efficiency of mechanical mixing of the polymer PM and the depolymerizing material can be further improved.

[0148] Figure 18A fourth embodiment of the recycling system according to the present invention is schematically shown. The same reference numerals are used to denote the same components as in the above embodiments, and descriptions of the same general meaning are omitted. The recycling system according to the fourth embodiment includes a partial depolymerization unit 730, a solid-liquid separation unit 740, a degraded material recycling unit 750, and a mechanical recycling device 900. The mechanical recycling device 900 and... Figure 5 The second embodiment is constructed in the same manner. Furthermore, the partial depolymerization unit 730, the solid-liquid separation unit 740, and the degraded material recovery unit 750 are similar to... Figures 7-12 The third embodiment is constructed in the same manner.

[0149] In this embodiment, the surface and other parts of the solid material, which are prone to quality deterioration, are partially decomposed, while the relatively high-quality solid components are separated. Thus, by mechanically recycling the high-quality solid components, the quality of the recycled product can be stabilized.

[0150] Furthermore, according to this embodiment, the partial depolymerization section 730 and the solid-liquid separation section 740 effectively remove surface portions prone to quality deterioration, thereby reliably obtaining high-quality solid materials (solid components). Therefore, typically, a chemical recovery device 100 suitable for low-quality solid materials is unnecessary. Figure 7 It can be recycled quickly and efficiently using a mechanical recycling device 900, which has a simpler structure and lower operating costs compared to other devices.

[0151] Furthermore, the recycling system according to this embodiment, through the partial depolymerization section 730 and the solid-liquid separation section 740, can effectively remove surface portions that are prone to quality deterioration, and therefore can also accept low-quality PET fragments and other fixation materials. Thus, according to this embodiment, a highly versatile recycling system capable of handling a wide range of fixation materials can be provided.

[0152] Figure 19 A fifth embodiment of the recycling system according to the present invention is schematically shown. The same reference numerals are used to denote the same components as in the above embodiments, and descriptions of the same general meaning are omitted. The recycling system according to the fifth embodiment replaces the partial depolymerization unit 730 and the solid-liquid separation unit 740. Figure 5 The structure of the quality determination unit 710 and the material sorting unit 720 in the second embodiment.

[0153] The high-quality solid components separated by the solid-liquid separation unit 740 are efficiently recovered through a simple mechanical recovery process (mechanical recovery device 900) with low quality improvement effect, while the low-quality liquid components separated by the solid-liquid separation unit 740 are recovered through a chemical recovery process (chemical recovery device 100) with high quality improvement effect, thus improving their quality. Furthermore, since the liquid components have already been depolymerized in the partial depolymerization unit 730, they can be directly supplied to the foreign matter removal devices 340-360 without passing through the depolymerization reaction tank 300 in the chemical recovery device 100. In these foreign matter removal devices 340-360, pollutants contained in the liquid components are effectively removed.

[0154] Figure 20 A sixth embodiment of the recycling system according to the present invention is schematically shown. The same reference numerals are used for components identical to those in the above embodiments, and descriptions of the same general meaning are omitted. In the recycling system according to the sixth embodiment, a first partial depolymerization unit 731 and a second partial depolymerization unit 732, identical to the partial depolymerization unit 730, are provided, as are a first solid-liquid separation unit 741 and a second solid-liquid separation unit 742, identical to the solid-liquid separation unit 740.

[0155] Solid materials such as PET fragments are supplied to the first depolymerization section 731 and the first solid-liquid separation section 741. The low-quality liquid components separated by the first solid-liquid separation section 741 are recovered by the deteriorated material recovery section 750. On the other hand, the medium-quality solid components separated by the first solid-liquid separation section 741 are supplied to the second depolymerization section 732 and the second solid-liquid separation section 742.

[0156] The high-quality solid components separated by the second solid-liquid separation unit 742 are efficiently recovered through a simple mechanical recovery process (mechanical recovery device 900) with low quality improvement effect. The medium-quality liquid components separated by the second solid-liquid separation unit 742 are recovered through a chemical recovery process (chemical recovery device 100) with high quality improvement effect, thus improving their quality. Furthermore, since the liquid components have already been depolymerized in the second depolymerization unit 732, they can be directly supplied to the foreign matter removal devices 340-360 without passing through the depolymerization reaction tank 300 in the chemical recovery device 100. In these foreign matter removal devices 340-360, contaminants contained in the liquid components are effectively removed.

[0157] In this embodiment, the low-quality liquid component separated by the first solid-liquid separation unit 741 is not supplied to the chemical recovery device 100, while the medium-quality liquid component separated by the second solid-liquid separation unit 742 in the second stage is supplied to the chemical recovery device 100, thereby reducing the burden on the chemical recovery device 100.

[0158] exist Figure 5 The quality determination unit 710 and / or material sorting unit 720 illustrated in the second embodiment are... Figure 7 The third implementation method Figure 18 The fourth implementation method Figure 19 The fifth embodiment and Figure 20 The partial depolymerization section 730 and / or solid-liquid separation section 740 illustrated in the sixth embodiment can be combined in various ways. Several specific examples of such embodiments are shown below. The same reference numerals are used to denote the same components as in the foregoing embodiments, and descriptions of the same general meaning are omitted.

[0159] Figure 21 The seventh embodiment of the recycling system according to the present invention is schematically illustrated. In this embodiment, high-quality materials sorted by the material sorting unit 720 are supplied to the mechanical recycling device 900, while low-quality materials sorted by the material sorting unit 720 are supplied to the partial depolymerization unit 730 and the solid-liquid separation unit 740. Then, solid components including high-quality PET and the like separated by the solid-liquid separation unit 740 are supplied together with the high-quality materials sorted by the material sorting unit 720 to the mechanical recycling device 900.

[0160] In this embodiment, the high-quality materials sorted by the material sorting unit 720 are not subjected to partial depolymerization treatment based on the partial depolymerization unit 730, thus preventing the removal of high-quality PET and the like during this partial depolymerization treatment. Furthermore, a chemical recovery device 100 can be provided instead of the mechanical recovery device 900 in this embodiment.

[0161] Figure 22 The eighth embodiment of the recycling system according to the present invention is schematically shown. In this embodiment, solid materials such as PET fragments are supplied to a partial depolymerization unit 730 and a solid-liquid separation unit 740. The low-quality liquid components separated by the solid-liquid separation unit 740 are recovered by a deteriorated material recovery unit 750. On the other hand, the solid components separated by the solid-liquid separation unit 740 are supplied to a quality determination unit 710 and a material sorting unit 720.

[0162] High-quality materials sorted by the material sorting unit 720 are efficiently recovered through mechanical recycling treatment (mechanical recycling device 900), which has low quality improvement effect but simple equipment. Low-quality materials sorted by the material sorting unit 720 are recovered through chemical recycling treatment (chemical recycling device 100), which has high quality improvement effect, thus improving their quality.

[0163] In this embodiment, the low-quality liquid component separated by the solid-liquid separation unit 740 is not supplied to the chemical recovery device 100, while the low-quality material sorted by the material sorting unit 720 (however, its quality is higher than that of the liquid component separated by the solid-liquid separation unit 740) is supplied to the chemical recovery device 100, thereby reducing the burden on the chemical recovery device 100.

[0164] Figure 23 A ninth embodiment of the recycling system according to the present invention is schematically illustrated. In this embodiment, solid materials such as PET fragments are supplied to a quality determination unit 710 and a material sorting unit 720. High-quality materials sorted by the material sorting unit 720 are supplied to a first partial depolymerization unit 731 (high-quality material partial depolymerization unit) and a first solid-liquid separation unit 741. The solid components separated by the first solid-liquid separation unit 741 are supplied to a mechanical recycling device 900, and the liquid components separated by the first solid-liquid separation unit 741 are supplied to a chemical recycling device 100. Low-quality materials sorted by the material sorting unit 720 are supplied to a second partial depolymerization unit 732 (low-quality material partial depolymerization unit) and a second solid-liquid separation unit 742. The solid components separated by the second solid-liquid separation unit 742 are supplied to the chemical recycling device 100, and the liquid components separated by the second solid-liquid separation unit 742 are recovered through a degraded material recycling unit 750.

[0165] The present invention has been described above based on embodiments. Various modifications can be achieved in the combinations of the constituent elements and processes in the illustrated embodiments, and such modifications are included within the scope of the present invention, as will be apparent to those skilled in the art.

[0166] Furthermore, the configuration, function, and purpose of each apparatus and method described in the embodiments can be implemented using hardware resources, software resources, or through the collaboration of hardware and software resources. Hardware resources include, for example, processors, ROMs, RAMs, and various integrated circuits. Software resources include, for example, operating systems, application programs, and other programs.

[0167] Industrial availability This invention relates to recycling systems, etc.

[0168] Symbol Explanation 1-Injection molding machine, 100-Chemical recovery device, 200-Polymer conditioning device, 300-Depolymerization reaction tank, 340-Irrelevant resin removal device, 350-Colorant removal device, 360-Metal ion removal device, 400-Polymerization reaction tank, 500-Polymerization accelerator, 600-Polymer supply unit, 710-Quality judgment unit, 720-Material sorting unit, 730-Partial depolymerization unit, 731-First part depolymerization unit, 732 - Part 2 Depolymerization Section, 740- Solid-Liquid Separation Section, 741- First Solid-Liquid Separation Section, 742- Second Solid-Liquid Separation Section, 750- Degraded Material Recovery Section, 810- Partial Depolymerization Reaction Tank, 820- Solid Material Supply Section, 830- Depolymerization Material Supply Section, 840- Depolymerization Discharge Section, 850- Solid Component Removal Section, 860- Partition Plate, 870- Stirring Blades, 880- Baffle Plate, 900- Mechanical Recovery Device, 910- Heater.

Claims

1. A recycling system comprising: a quality judging section that judges a quality of a solid material containing a polymer that is a recycling target, based on a predetermined quality judging criterion; a material sorting section that sorts the solid material into a high-quality material that is judged to have a quality higher than the quality judging criterion and a low-quality material that is judged to have a quality lower than the quality judging criterion; a mechanical recycling device that performs a mechanical recycling process on the high-quality material; and a chemical recycling device that performs a chemical recycling process on the low-quality material.

2. The recycling system according to claim 1, wherein the chemical recycling device comprises a depolymerization reaction tank that decomposes the low-quality material into a depolymerized material through a depolymerization reaction, a foreign matter removing device that is provided at a rear stage of the depolymerization reaction tank and removes foreign matter from the depolymerized material, a polymerization reaction tank that is provided at a rear stage of the foreign matter removing device and synthesizes the depolymerized material into the polymer through a polymerization reaction, and a polymerization promoting device that is provided at a rear stage of the polymerization reaction tank and increases a degree of polymerization of the polymer.

3. The recycling system according to claim 2, wherein the mechanical recycling device and the chemical recycling device share the polymerization promoting device to increase the degree of polymerization of the high-quality material.

4. The recycling system according to any one of claims 1 to 3, wherein the recycling system comprises a polymer supply section that is provided at a rear stage of the mechanical recycling device and the chemical recycling device and supplies the high-quality material subjected to the mechanical recycling process and the low-quality material subjected to the chemical recycling process to a molding machine in a mixed state.

5. The recycling system according to any one of claims 1 to 3, wherein a high-quality material partial depolymerization section that partially decomposes the high-quality material into a depolymerized material through a depolymerization reaction is provided between the material sorting section and the mechanical recycling device, a solid component obtained in the high-quality material partial depolymerization section is supplied to the mechanical recycling device, and a liquid component obtained in the high-quality material partial depolymerization section is supplied to the chemical recycling device.

6. The recycling system according to any one of claims 1 to 3, wherein a low-quality material partial depolymerization section that partially decomposes the low-quality material into a depolymerized material through a depolymerization reaction is provided between the material sorting section and the chemical recycling device, and a solid component obtained in the low-quality material partial depolymerization section is supplied to the chemical recycling device.

7. The recycling system according to any one of claims 1 to 3, wherein the polymer is polyethylene terephthalate.

8. A recycling method comprising the following steps performed by a computer: judging a quality of a solid material that is a recycling target, based on a predetermined quality judging criterion; sorting the solid material into a high-quality material that is judged to have a quality higher than the quality judging criterion and a low-quality material that is judged to have a quality lower than the quality judging criterion; performing a mechanical recycling process on the high-quality material; and performing a chemical recycling process on the low-quality material.

9. A storage medium storing a recycling program that causes a computer to perform the following steps: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ determining the quality of the solid material targeted for recycling according to a predetermined quality determination criterion; sorting the solid material into high-quality material determined to be higher in quality than the quality determination criterion and low-quality material determined to be lower in quality than the quality determination criterion; subjecting the high-quality material to a mechanical recycling process; and subjecting the low-quality material to a chemical recycling process.

Images