Depolymerization reaction monitoring device, depolymerization reaction monitoring method, and depolymerization reaction monitoring program

Abstract

A depolymerization reaction monitoring device 30 includes a depolymerization reaction vessel 300 that causes a depolymerization reaction in which a polyester such as polyethylene terephthalate is decomposed into a depolymerized product such as bis(2-hydroxyethyl) terephthalate by using a depolymerization material such as ethylene glycol, a property measuring unit 33 that measures a property of the depolymerization material in which the depolymerized product is dissolved at the depolymerization reaction vessel 300, and a progress monitoring unit 37 that monitors progress of the depolymerization reaction based on the property of the depolymerization material measured by the property measuring unit 33.The depolymerization reaction vessel 300 includes a vessel main body 31 that causes the depolymerization reaction, and a depolymerization material flow section 32 through which the depolymerization material flows between the vessel main body 31 and the depolymerization material flow section 32, and the property measuring unit 33 measures a property of the depolymerization material in the depolymerization material flow section 32.

Description

Technical area

[0001] The present invention relates to a depolymerization reaction monitoring device and the like. State of the art

[0002] PTL 1 discloses a method for producing polyethylene terephthalate (PET) flakes, which are raw materials for a new PET bottle, by crushing a PET bottle to recycle the PET bottle. Specifically, mechanical recycling to obtain PET flakes by solid-state polymerization or the like after heating and melting the crushed PET bottle, and chemical recycling to obtain PET flakes by a repolymerization reaction after decomposing the crushed PET bottle into an intermediate product such as bis(2-hydroxyethyl) terephthalate (BHET) or a depolymerized product through a depolymerization reaction are known. Citation listPatent literature [PTL 1] Japanese Unexamined Patent Publication No. 2016-153176 [PTL 2] Japanese Unexamined Patent Publication No. 2022-27158 Summary of the inventionTechnical problem

[0003] For efficient chemical recycling of PET or the like, it is important to adequately identify the progress of chemical reactions such as depolymerization reactions and repolymerization reactions. The progress of the chemical reaction can be identified by measuring a reaction product and / or a product collected from a reaction container. However, there are some inconveniences, such as the need for a special collection device to collect the reaction product and / or the product, and the need to stop the chemical reaction during collection.

[0004] The present invention has been made in view of such circumstances, and an object thereof is to provide a depolymerization reaction monitoring apparatus capable of efficiently identifying progress of a depolymerization reaction. Solution to problem

[0005] To solve the above problem, a depolymerization reaction monitoring device according to one aspect of the present invention comprises a depolymerization reaction vessel that causes a depolymerization reaction in which a polyester is decomposed into a depolymerized product by using a depolymerization material, a property measuring unit that measures a property of the depolymerization material in which the depolymerized product is dissolved at the depolymerization reaction vessel, and a progress monitoring unit that monitors progress of the depolymerization reaction based on the property of the depolymerization material measured by the property measuring unit.

[0006] In this aspect, it is possible to efficiently identify the progress of the depolymerization reaction of the polyester in which the depolymerized product, which is the product, is dissolved in the depolymerization material, which is the reaction product or the catalyst, by measuring the property of the depolymerization material in the reaction vessel for depolymerization.

[0007] Another aspect of the present invention provides a depolymerization reaction monitoring method. This method comprises causing a depolymerization reaction in which a polyester is decomposed into a depolymerized product by using a depolymerization material in a depolymerization reaction vessel, measuring a property of the depolymerization material in which the depolymerized product is dissolved in the depolymerization reaction vessel, and monitoring the progress of the depolymerization reaction based on the property of the measured depolymerization material.

[0008] Any combination of the components described above or any expression of these components converted into a method, apparatus, system, recording medium, computer program or the like is also included in the present invention. Advantageous effects of the invention

[0009] According to the present invention, progress of a depolymerization reaction can be efficiently identified. Brief description of the drawings Fig. Figure 1 schematically shows a configuration of a chemical recycling molding system. Fig. Figure 2 schematically shows a polymerization reaction and a depolymerization reaction of PET. Fig. 3 shows a modification example of a by-product removal device. Fig. 4 shows a first embodiment of a depolymerization reaction monitoring device. Fig. 5A and Fig. 5B show examples of monitoring progress of the depolymerization reaction by a progress monitoring unit. Fig. Figure 6 shows a second embodiment of a depolymerization reaction monitoring device. Fig. 7 shows an example of dilution of a depolymerization material by a depolymerization material dilution unit. Fig. 8 is a flowchart of a specific example of a measuring method in the second embodiment. Fig. 9 shows a third embodiment of a depolymerization reaction monitoring device. Fig. 10 is a flowchart of a specific example of a measuring method in the third embodiment. Description of embodiments

[0010] Hereinafter, an embodiment for carrying out the present invention (hereinafter also referred to as an embodiment) will be described in detail with reference to the drawings. In the description and / or drawings, identical or equivalent components, elements, and processes are denoted by the same reference numerals, and overlapping descriptions are omitted. The scale or shape of each part shown in the drawings is set for convenience and ease of description and is not interpreted as limiting unless otherwise specified. The embodiment is exemplary and does not limit the scope of the present invention in any way. All features to be described in the embodiment and combinations thereof are not necessarily essential to the present invention.

[0011] Fig. Figure 1 schematically shows a configuration of a chemical recycling molding system to which a depolymerization reaction monitoring device according to an embodiment of the present invention can be applied. The chemical recycling molding system includes a chemical recycling device 100 and an injection molding machine 1. The chemical recycling device 100 includes a polymer adjustment device 200, a depolymerization reaction tank 300, a polymerization reaction tank 400, a by-product removal device 500, and a polymer supply unit 600. The number of injection molding machines 1 (two are shown in Fig. 1), the number of polymer adjustment devices 200, the number of depolymerization reaction vessels 300, the number of polymerization reaction vessels 400, the number of by-product removal devices 500, and the number of polymer supply units 600 are optional. In particular, by increasing the number of injection molding machines 1 and polymerization reaction vessels 400, which typically have slower processing speeds or reaction rates than other processing units, processing efficiency can be improved so that these processing units do not become serious bottlenecks.

[0012] The polymer adjusting device 200 adjusts a polymer such as PET, which forms a first molded product such as a PET bottle, for the depolymerization reaction vessel 300 in a subsequent step. Specifically, the polymer adjusting device 200 performs a process such as crushing, heating, melting, and mixing on the first molded product such as a PET bottle, and adjusts the polymer such as PET to a suitable state (phase, shape, size, and the like) for a depolymerization reaction in the depolymerization reaction vessel 300. The first molded product may be any molded product other than a bottle, such as a sheet, a film, or a fiber. Furthermore, the polymer constituting the first molded product may be any polymer other than PET, such as polyester (including PET), polyamide, and polyurethane.

[0013] The depolymerization reaction tank 300 decomposes the polymer, such as PET, which has been adjusted by the polymer adjusting device 200 into a depolymerized product through a depolymerization reaction. In a case where the polymer supplied from the polymer adjusting device 200 is PET, BHET, which is an intermediate, is obtained as the depolymerized product through the depolymerization reaction in the depolymerization reaction tank 300. The depolymerized product obtained in the depolymerization reaction tank 300 may contain a monomer of the polymer. In a case where the polymer is PET, the monomer is, for example, ethylene glycol, terephthalic acid, dimethyl terephthalate, or ethylene terephthalate.As will be described in detail later, the depolymerization reaction monitoring apparatus according to the embodiment of the present invention may be configured to include the reaction vessel 300 for depolymerization.

[0014] As in Fig. 2, PET is depolymerized in the depolymerization reaction (300) of PET as a polymer by ethylene glycol (EG) as a depolymerization material supplied from a depolymerization material supply unit 310 ( Fig. 1) Depolymerization material supplied to the depolymerization reaction vessel 300 is decomposed, and BHET as a depolymerized product is obtained. Furthermore, instead of the depolymerization material supply unit 310 or in addition to it, EG may be supplied to the polymer adjustment device 200. To promote such a depolymerization reaction, an inside of the depolymerization reaction vessel 300 is heated by a heating unit 320 ( Fig. 1) or a temperature maintenance unit provided in connection with the reaction vessel 300 for depolymerization, at a suitable temperature for the depolymerization reaction. A suitable temperature for the depolymerization reaction of the PET to the BHET in Fig. 2 is between 180 °C and 250 °C, is preferably between 230 °C and 245 °C and is more preferably between 235 °C and 240 °C. In addition, a suitable pressure for the depolymerization reaction of the PET to the BHET is Fig. 2 between normal pressure (0 MPa, G) and 0.8 MPa, G, is preferably between 0.4 MPa, G and 0.6 MPa, G, and is more preferably between 0.45 MPa, G and 0.55 MPa, G. Note that the pressure unit, MPa, G, refers to overpressure. The pressure in the depolymerization reaction vessel 300 is adjusted by a pump (not shown) or the like provided in connection with the depolymerization reaction vessel 300.

[0015] A viscosity of a fluid in the depolymerization reaction vessel 300, in which BHET with a lower molecular weight than PET, which is a polymer, is produced, is lower than a viscosity of a fluid in the polymerization reaction vessel 400, which will be described later, in which PET with a larger molecular weight is produced. Therefore, a low-viscosity stirring blade 330 is used to stir the fluid in the depolymerization reaction vessel 300 to promote the depolymerization reaction. A propeller blade, a disc agitator blade, and a paddle blade are exemplified as the low-viscosity stirring blade 330.

[0016] In the subsequent stage of the depolymerization reaction vessel 300, foreign matter removal devices 340, 350, and 360 are provided for removing foreign matter from the fluid consisting mainly of BHET as the depolymerized product. A different resin removal device 340 removes a resin and / or a depolymerized product that differs from a target resin, such as PET, by using principles of flotation separation and sedimentation removal. A dye removal device 350 removes a dye material by using activated carbon or the like. A metal ion removal device 360 ​​removes metal ions using a principle such as ion exchange.A buffer tank 370 is provided in the subsequent stage of the foreign matter removing devices 340, 350 and 360 to temporarily store the fluid consisting mainly of BHET or the like after the foreign matter is removed before supplying the fluid into the reaction tank 400 for polymerization.

[0017] In the buffer tank 370, a first preheater 371 may be provided for heating or maintaining the temperature of the depolymerized product (a fluid composed mainly of BHET or the like) before it is supplied to the polymerization reaction tank 400 of the subsequent stage. The first preheater 371 may maintain the depolymerized product at the same temperature (between 180°C and 250°C) as that of the heating unit 320 provided in conjunction with the depolymerization reaction tank 300, or may maintain the depolymerized product at a temperature suitable for a polymerization reaction (between 250°C and 300°C), which is the same as that of a heating unit 410 provided in conjunction with the polymerization reaction tank 400, which will be described later.In this way, by providing the buffer tank 370 including a preheating mechanism (first preheater 371) as required in the previous stage of the polymerization reaction tank 400, it is possible to store the depolymerized product waiting to be supplied to the polymerization reaction tank 400, which typically has a slower processing speed or reaction rate than other processing units, such as the depolymerization reaction tank 300 and the by-product removal device 500, which will be described later, while maintaining the depolymerized product at a suitable temperature.As a result, the capacity of the entire chemical recycling device 100 can be increased, and the chemical recycling device 100 can be operated stably and continuously (without causing so-called "resin shortage") while timely supplying an appropriate amount of a reaction product to each of the processing units, such as the depolymerization reaction tank 300, the polymerization reaction tank 400, the by-product removal device 500, and the polymer supply unit 600. The preheating mechanism, such as the first preheater 371, is not limited to the buffer tank 370 and can be provided at any location (for example, the foreign matter removal devices 340, 350, and 360) between the depolymerization reaction tank 300 and the polymerization reaction tank 400 in any manner.

[0018] The polymerization reaction vessel 400 synthesizes the depolymerized product, such as BHET, produced in the depolymerization reaction vessel 300 and from which the impurity is removed by the impurity removal devices 340, 350, and 360, into the polymer through the polymerization reaction. In a case where the depolymerized product produced in the depolymerization reaction vessel 300 is BHET, PET, which is the polymer, is obtained again through the polymerization reaction in the polymerization reaction vessel 400.

[0019] As in Fig. As schematically shown in FIG. 2, EG is produced as a by-product together with PET as a main product, which is a polymer, in the polymerization reaction (400) of BHET as the depolymerized product. The EG can be circulated to the depolymerization material supply unit 310 and used for the depolymerization reaction of PET in the depolymerization reaction tank 300. Since the EG produced in the polymerization reaction tank 400 can be reused on-site (in the depolymerization reaction tank 300) without being wasted, the operating efficiency of the chemical recycling device 100 can be improved. In particular, the amount of EG to be purchased for the depolymerization reaction of PET in the depolymerization reaction tank 300 can be significantly reduced, so that the operating cost of the chemical recycling device 100 can be reduced.

[0020] In order to promote the polymerization reaction as described above, an inside of the reaction vessel 400 for polymerization is heated by the heating unit 410 ( Fig. 1) or the temperature maintenance unit, which serves as a second heating unit provided in connection with the reaction vessel 400 for polymerization, is maintained at a suitable temperature for the polymerization reaction. The suitable temperature for the polymerization reaction of BHET to PET in Fig. 2 is between 250°C and 300°C, preferably between 260°C and 290°C, and more preferably between 270°C and 280°C. Here, a heating temperature for polymerization by the heating unit 410 provided in conjunction with the polymerization reaction vessel 400 is higher than a heating temperature for depolymerization by the heating unit 320 provided in conjunction with the depolymerization reaction vessel 300. Although PET with a large molecular weight and a high melting point is produced in the polymerization reaction vessel 400, the temperature of the polymerization reaction vessel 400 is maintained higher than a temperature of the depolymerization reaction vessel 300 in which BHET with a small molecular weight and a low melting point is produced, so that PET, which is the main product of the polymerization reaction vessel 400, is maintained in a molten state.It is preferred that the polymerization reaction of BHET to PET takes place in . Fig. 2 is carried out in a vacuum state. For this reason, the reaction vessel 400 for polymerization is provided in conjunction with a vacuum pump or the like (not shown).

[0021] The viscosity of the fluid in the polymerization reaction vessel 400, in which PET with a high molecular weight is produced, is higher than the viscosity of the fluid in the depolymerization reaction vessel 300, in which BHET with a smaller molecular weight than the PET that is the polymer is produced. Therefore, a stirring blade 420 is used to stir the fluid in the polymerization reaction vessel 400 to promote the polymerization reaction at high viscosity. Examples of the high-viscosity stirring blade 420 include an anchor blade and a ribbon coil blade.

[0022] As a numerical value that correlates with a degree of polymerization of a polymer such as PET, an intrinsic viscosity (IV) or internal viscosity is known. The IV value (dL / g) is also used as an index of the polymer's use, and for PET, an IV value of about 0.72 or more can be used for a bottle, an IV value of about 0.65 or more can be used for a plate, a film, or the like, and an IV value of about 0.58 or more can be used for fibers. In the present embodiment, the objective is to finally obtain PET with an IV value that can be used for a bottle or a plate. As described later, since the IV value is also increased in the by-product removal device 500 in the subsequent stage of the polymerization reaction vessel 400, the IV value of the PET synthesized in the polymerization reaction vessel 400 can be relatively low.In particular, the IV value of the PET synthesized in the reaction vessel 400 for polymerization is between 0.2 and 0.7, preferably between 0.3 and 0.7, and more preferably between 0.3 and 0.55.

[0023] A buffer tank 430 may be provided at the subsequent stage of the polymerization reaction tank 400 for temporarily storing the polymer synthesized in the polymerization reaction tank 400 before supplying the polymer to the by-product removal device 500 in the subsequent stage and / or the polymer supply unit 600. A second preheater 431 may be provided in the buffer tank 430 for heating or maintaining the temperature of the polymer before supplying it to the by-product removal device 500 and / or the polymer supply unit 600 in the subsequent stage.The second preheater 431 can keep the polymer at the same temperature (between 250°C and 300°C) as that of the heating unit 410 provided in connection with the reaction vessel 400 for polymerization, can keep the polymer at a suitable temperature (between 250°C and 290°C) for the polymerization reaction, which is the same as that of a heating unit 520 provided in connection with the by-product removal device 500, which will be described later, or can keep the polymer at the same temperature (between 250°C and 290°C) as that of a heating unit 620 provided in connection with the polymer supply unit 600, which will be described later.

[0024] By providing the buffer tank 430 containing the preheating mechanism (second preheater 431) as needed in the previous stage of the by-product removing device 500 and / or the polymer supply unit 600, it is possible to store the polymer waiting to be supplied to the by-product removing device 500 and / or the polymer supply unit 600 while maintaining the polymer at an appropriate temperature.As a result, the capacity of the entire chemical recycling device 100 can be increased, and the chemical recycling device 100 can be operated stably and continuously (without causing so-called "resin shortage") while timely supplying an appropriate amount of a reaction product to each of the processing units, such as the depolymerization reaction tank 300, the polymerization reaction tank 400, the by-product removal device 500, and the polymer supply unit 600. The preheating mechanism, such as the second preheater 431, is not limited to the buffer tank 430 and can be provided at any location between the polymerization reaction tank 400 and the by-product removal device 500 and / or at any location between the by-product removal device 500 and the polymer supply unit 600 in any manner.

[0025] At the subsequent stage of the polymerization reaction vessel 400 (and a preceding stage of the polymer supply unit 600, which will be described later), the by-product removal device 500 is provided, through which PET (main product) and EG (by-product) generated by the polymerization reaction in the polymerization reaction vessel 400 flow and which removes the EG as the by-product. The by-product removal device 500 in the shown example includes a large number of linear elements 510 extending from top to bottom. Due to the increased surface area provided by the large number of linear elements 510, the volatilization of EG adhering to the surface of each linear element 510 is promoted, and the EG is effectively separated from and removed from the high-viscosity PET.

[0026] The EG can be circulated to the depolymerization material supply unit 310 and used for the depolymerization reaction of PET in the depolymerization reaction tank 300. Since the EG separated and removed in the by-product removal device 500 can be reused on-site (in the depolymerization reaction tank 300) without being wasted, the operating efficiency of the chemical recycling device 100 can be improved. In particular, the amount of EG to be purchased for the depolymerization reaction of PET in the depolymerization reaction tank 300 can be significantly reduced, so that the operating cost of the chemical recycling device 100 can be reduced.

[0027] Furthermore, the PET with a relatively low polymerization degree (i.e., an IV value) and the BHET unreacted in the polymerization reaction vessel 400 also adhere to the surface of each of the linear members 510, so that the polymerization reaction similar to that in the polymerization reaction vessel 400 effectively proceeds due to a large surface area. For this reason, the IV value of PET as the main product is increased by passing through the by-product removal device 500. Specifically, the IV value of the PET after passing through the by-product removal device 500 is 0.7 or more, preferably 0.8 or more, and more preferably 0.85 or more.

[0028] In order to promote such a polymerization reaction, an inside of the by-product removing device 500 is heated by the heating unit 520 ( Fig. 1) or the temperature maintenance unit serving as the second heating unit provided in conjunction with the by-product removal device 500 is maintained at a suitable temperature for the polymerization reaction. Specifically, the heating temperature by the heating unit 520 is between 250°C and 290°C, and preferably between 260°C and 280°C. Here, the heating temperature by the heating unit 520 provided in conjunction with the by-product removal device 500 is preferably higher than a heating temperature for polymerization by the heating unit 410 provided in conjunction with the polymerization reaction vessel 400. In the by-product removal device 500, the polymerization reaction proceeds further than in the polymerization reaction vessel 400, resulting in a larger molecular weight of PET as a polymer and a higher melting point.By maintaining a higher temperature inside the by-product removal device 500 than inside the polymerization reaction vessel 400, the PET as a product of the by-product removal device 500 can be kept in a molten state. A heating unit or a temperature-maintaining unit serving as a second heating unit for heating or maintaining the temperature at least at the heating temperature for polymerization by the heating unit 410 provided in connection with the polymerization reaction vessel 400 may be provided around a pipe or the like between the polymerization reaction vessel 400 and the by-product removal device 500. Furthermore, it is preferable that the polymerization reaction in the by-product removal device 500 be carried out in a vacuum state in the same manner as the polymerization reaction in the polymerization reaction vessel 400.For this reason, the by-product removal device 500 is provided in conjunction with a vacuum pump or the like (not shown). The EG as the by-product can be efficiently removed by setting the interior of the by-product removal device 500 in a vacuum state (reduced pressure state).

[0029] The configuration of the by-product removal device 500 is not limited to a “vertical type” as in Fig. 1. For example, a stirring device of a “twin-shaft horizontal type” as shown in Fig. 3, as the by-product removal device 500. The stirring device includes two rotary shafts that rotate in a direction opposite to the paper plane of Fig. 3, and two stirring blades that rotate around each of the rotating shafts to stir PET and EG as stirring targets. The volatilization of the EG is promoted by stirring it through the two stirring blades, so that the EG is effectively separated and removed from the high-viscosity PET. The details of the stirring device are shown in Fig. 3 are disclosed in Japanese Patent No. 2925599, which is incorporated herein by reference.

[0030] The polymer supply unit 600 supplies the polymer, such as PET, synthesized in the polymerization reaction vessel 400 (or the polymerization reaction vessel 400 and the by-product removal device 500) to the injection molding machine 1, which molds the second molded product, such as a PET bottle. The polymer supply unit 600 includes a feed pump 610, such as a gear pump or a screw pump, suitable for feeding the high-purity and high-viscosity (i.e., high polymerization degree or high IV value) PET, from which the EG as the by-product is removed in the by-product removal device 500, into the injection molding machine 1 in a molten state.

[0031] The polymer supply unit 600 is provided with the heating unit 620 or the temperature maintenance unit as a first heating unit for heating or maintaining the temperature of the polymer, such as PET, to be transferred to the injection molding machine 1 by the feed pump 610 to keep it in a molten state. Specifically, the heating temperature by the heating unit 620 is between 250°C and 290°C, and preferably between 260°C and 280°C.Here, the heating temperature (first heating temperature) by the heating unit 620 (first heating unit) provided in the polymer supply unit 600 is preferably higher than a second heating temperature by the second heating unit, such as the heating unit 410 provided in connection with the polymerization reaction vessel 400, the heating unit 520 provided in connection with the by-product removal device 500, and a heating unit (not shown) provided between the polymerization reaction vessel 400 and the by-product removal device 500. The polymerization reaction that starts in the polymerization reaction vessel 400 gradually progresses and is completed in the by-product removal device 500.As a result, the molecular weight of the polymer such as PET in the polymer supply unit 600 becomes larger and the melting point thereof becomes higher than in the reaction vessel 400 for polymerization and the by-product removal device 500. Therefore, by making the first heating temperature in the polymer supply unit 600 higher compared to the previous second heating temperature, the polymer such as PET having a high viscosity (i.e., high degree of polymerization or high IV value) and a high melting point can be kept in a molten state.

[0032] A temperature gradient may be provided so that the heating temperature increases gradually from the reaction vessel 400 for polymerization to the polymer supply unit 600.For example, by making the heating temperature by a heating unit (not shown) provided between the polymerization reaction vessel 400 and the by-product removal device 500 higher than the heating temperature by the heating unit 410 provided in connection with the polymerization reaction vessel 400, the heating temperature by the heating unit 520 provided in connection with the by-product removal device 500 higher than the heating temperature by the heating unit (not shown), and the heating temperature by the heating unit 620 provided in the polymer supply unit 600 higher than the heating temperature by the heating unit 520, it is possible to reliably keep the polymer, such as PET, whose melting point increases from the polymerization reaction vessel 400 to the polymer supply unit 600, in a molten state.A heating unit for heating or maintaining the temperature of the polymer, such as PET, to keep it in a molten state may be provided between the polymer supply unit 600 and the injection molding machine 1.

[0033] The injection molding machine 1 molds the polymer, such as PET, in a molten state generated by the chemical recycling device 100 into a second molded product. The second molded product may be the same as or different from the first molded product, which is subjected to a crushing process or the like by the polymer adjusting device 200. For example, the first molded product and the second molded product may both be PET bottles. Moreover, one of the first molded product and the second molded product may be a PET bottle, and the other may be a molded product other than a bottle, such as a sheet, a film, and a fiber. Generally, in mechanical recycling, the IV value of the second molded product after recycling becomes lower than the IV value of the first molded product before recycling.However, according to the chemical recycling device 100 of the present embodiment, which includes the mechanism for increasing IV values, such as the foreign matter removal devices 340, 350, and 360 and the by-product removal device 500, it is also possible to increase the IV value of the second molded product after recycling to be higher than the IV value of the first molded product before recycling. For example, according to the present embodiment, the PET fiber with a low IV value as the first molded product can be recycled into the PET bottle with a high IV value as the second molded product.

[0034] The injection molding machine 1 forms a molten resin, such as PET, into a second molded product. An injection molding machine using a molten resin as a raw material is disclosed, for example, in Japanese Unexamined Patent Publication No. 2022-27158. This application incorporates the entire contents of the literature filed on July 31, 2020 (Japanese Patent Application No. 2020-130985) by reference. As described in Fig. As shown schematically in FIG. 1, a plurality of injection molding machines 1 may be provided in parallel. The molding machine to which the molten resin or the like is supplied from the chemical recycling device 100 is not limited to an injection molding machine and may be any molding machine (for example, a compression molding machine).

[0035] In the present embodiment, as described above, the polymer resynthesized in the reaction tank 400 for polymerization is not processed into flakes or pellets and is supplied as it is to the injection molding machine 1 through the polymer supply unit 600. Since the cooling process and the heating process with respect to the flakes or pellets as in the prior art are not required, the molded product, such as a PET bottle, can be recycled with less energy compared to the prior art.

[0036] In the chemical recycling apparatus 100 according to the present embodiment, since the polymer resynthesized in the polymerization reaction tank 400 is supplied as it is to the injection molding machine 1, it is necessary to quickly realize the IV value of the polymer required for the molded product (second molded product). In the present embodiment, the by-product removal device 500, which has a function of promoting the polymerization reaction and increasing the IV value of the polymer, is provided in addition to the polymerization reaction tank 400. Therefore, the by-product removal device 500 can sufficiently meet such a requirement.

[0037] In the example of Fig. 1, only one of the polymer adjustment device 200, the depolymerization reaction tank 300, the polymerization reaction tank 400, the by-product removal device 500, the polymer supply unit 600, and the like is provided, but multiple of each of them may be provided. The multiple processing units can perform the same processing in parallel, so the processing performance of the processing unit group can be improved. Furthermore, the difference in processing speed or reaction rate between the processing units can be reduced by increasing the number of slow processing units.

[0038] In addition, one or more of the processing units may receive external material from a location or facility different from the one in Fig. 1, instead of or in addition to the material from the processing unit in the previous stage. For example, in a case where a plurality of the polymerization reaction vessels 400 are provided, some of the polymerization reaction vessels 400 may be supplied with the depolymerized product from the depolymerization reaction vessel 300, and the others may be supplied with the depolymerized product (synonymous with the depolymerized product supplied from a depolymerized product supply unit 300A, which will be described later) acquired from the outside.Similarly, in a case where a plurality of the by-product removal devices 500 and / or the polymer supply units 600 are provided, some of the by-product removal devices 500 and / or the polymer supply units 600 may be supplied with the polymer from the polymerization reaction vessel 400, and the others may be supplied with the polymer acquired from the outside (synonymous with the polymer supplied from a polymer supply unit 400A, which will be described later). By allowing the intake of the external material at each processing stage in the chemical recycling molding system, the flexibility of the chemical recycling molding system can be ensured, and the system can operate efficiently.

[0039] Fig. Figure 4 shows a first embodiment of a depolymerization reaction monitoring device 30 according to the present invention. The depolymerization reaction monitoring device 30 is configured to contain the above-described depolymerization reaction vessel 300. The depolymerization reaction vessel 300 causes a depolymerization reaction in which the polyester is decomposed into a depolymerized product by using the depolymerization material. In the present embodiment, as shown in Fig. 2, the polyester is polyethylene terephthalate (PET), the depolymerization material is ethylene glycol (EG), and the depolymerized product is bis(2-hydroxyethyl)terephthalate (BHET).

[0040] However, the present invention is also applicable to combinations of the polyester, the depolymerization material, and the depolymerized product that differ from these. For example, the polyester may be polypropylene terephthalate (PPT), the depolymerization material may be propylene glycol (PG), and the depolymerized product may be bis(2-hydroxypropyl) terephthalate (BHPT). Furthermore, the polyester may be polybutylene terephthalate (PBT), the depolymerization material may be butylene glycol (BG), and the depolymerized product may be bis(2-hydroxybutyl) terephthalate (BHBT).Such a combination of the polyester, the depolymerization material, and the depolymerized product has a common feature that the depolymerized product (BHET, BHPT, BHBT, or the like), which is the product of the depolymerization reaction, is dissolved in the depolymerization material (EG, PG, BG, or the like), which is one of the reaction products or the catalyst in the depolymerization reaction, while the polyester (PET, PPT, PBT, or the like), which is the other reaction product of the depolymerization reaction, is not dissolved in the depolymerization material (EG, PG, BG, or the like).

[0041] Furthermore, as long as the same characteristics are observed, the depolymerization reaction monitoring device 30 according to the present embodiment can be used to monitor the progress of the depolymerization reaction of a polymer other than a polyester, such as a polyamide or a polyurethane. That is, the depolymerization reaction monitoring device 30 according to the present embodiment is applicable as long as the depolymerized product, which is a product of the depolymerization reaction, is dissolved in the depolymerization material, which is one of the reaction products or the catalyst of the depolymerization reaction, while the polymer, which is the other reaction product of the depolymerization reaction, is not dissolved in the depolymerization material.

[0042] In this way, the depolymerization device 30 according to the present embodiment, as described above, is not limited to the Fig. 1 shown chemical recycling molding system and is applicable to the depolymerization reaction vessel 300 provided in any system or in any stand-alone depolymerization reaction vessel 300. Furthermore, the depolymerization reaction monitoring device 30 in the example of Fig. 4 is provided only on one side portion of the depolymerization reaction vessel 300, but may be provided in any number (for example, several) at any portions (for example, a bottom surface) not limited to the side portion of the depolymerization reaction vessel 300. Furthermore, the depolymerization reaction monitoring device 30 may be provided in the subsequent stage of the depolymerization reaction vessel 300 and the preceding stage of the polymerization reaction vessel 400. For example, the depolymerization reaction monitoring device 30 may be provided in a pipe between the depolymerization reaction vessel 300 and the polymerization reaction vessel 400 in Fig. 1 or in the buffer tank 370 in addition to or instead of the depolymerization reaction tank 300. In a case where a plurality of depolymerization reaction tanks 300 are connected in parallel, an average value of the degree of progress of the depolymerization reaction in the plurality of depolymerization reaction tanks 300 can be identified in the buffer tank 370 or the like. in which the depolymerization product liquid is collected in a subsequent stage of the plurality of reaction vessels 300 for depolymerization.

[0043] In a case where the plurality of depolymerization reaction vessels 300 are connected in series or parallel, any number of depolymerization reaction monitoring devices 30 may be provided at any portion of each of the depolymerization reaction vessels 300. It is preferable that the monitoring results (specifically, the measurement results obtained by the property measurement unit 33 described later or the monitoring results obtained by the progress monitoring unit 37) obtained by the respective depolymerization reaction monitoring devices 30 in the respective depolymerization reaction vessels 300 be shared or listed among the plurality of depolymerization reaction vessels 300.For example, in a case where the plurality of depolymerization reaction vessels 300 are connected in series, the progress of each stage of the depolymerization reaction can be accurately identified by each of the depolymerization reaction monitoring devices 30 provided in each of the depolymerization reaction vessels 300. The residence time of the reaction liquid and / or the product liquid in each of the depolymerization reaction vessels 300, as well as the movement timing and speed of the reaction liquid and / or the product liquid between the adjacent depolymerization reaction vessels 300, can be adaptively adjusted according to the progress of the depolymerization reaction in each of these stages.

[0044] The depolymerization reaction vessel 300 includes a vessel main body 31 in which the depolymerization reaction of the polyester or a polymer occurs, and a depolymerization material flow section 32 through which a depolymerization material, such as EG, flows between the vessel main body 31 and the depolymerization material flow section 32. The depolymerization material flow section 32 forms a flow path of the depolymerization material, such as EG, outside the vessel main body 31. As shown in the drawings, one end 321 and the other end 322 of the tubular depolymerization material flow section 32 are connected to different locations on the vessel main body 31.As described later, the depolymerization material, such as EG, may flow from one end 321 to the other end 322 of the depolymerization material flow section 32 or may flow from the other end 322 to the one end 321 of the depolymerization material flow section 32.

[0045] The depolymerization material flow section 32 is provided with the property measuring unit 33, a penetration preventing unit 34, a direction switching unit 35 and a cooling unit 36.

[0046] The property measurement unit 33 measures properties of a depolymerization material, such as EG, in which a depolymerized product, such as BHET, is dissolved in the depolymerization reaction vessel 300. Specifically, the property measurement unit 33 measures the properties of the depolymerization material, such as EG, in the depolymerization material flow section 32.

[0047] The property measuring unit 33 in the example of Fig. 4 measures optical properties of the depolymerization material, such as EG, in the depolymerization material flow section 32. The property measuring unit 33 includes a light source 331, a light receiving unit 332, and a window 333. The light source 331 emits light of any intensity, pattern, wavenumber, wavelength, frequency, or other aspects suitable for measuring the optical characteristics of the depolymerization material, such as EG, in which the depolymerized product, such as BHET, is dissolved. The light from the light source 331 passes through a light-transmitting window 333, which forms part of a tube wall of the tubular depolymerization material flow section 32, and enters the interior of the depolymerization material flow section 32 to irradiate the depolymerization material, such as EG.The light is subjected to optical effects such as reflection, refraction, absorption, scattering, diffraction, polarization, interference, and dispersion according to the optical effects of the depolymerization material, such as EG, in which the depolymerized product, such as BHET, is dissolved. The light receiving unit 332 receives the light that has undergone such optical effects through the window 333. As a preferable material for the window 333, borosilicate glass, cobalt glass, quartz, and aluminosilicate glass are exemplified. The light received by the light receiving unit 332 represents the optical characteristics of the depolymerization material, such as EG, in which the depolymerized product, such as BHET, is dissolved. As the optical properties that can be measured by the property measuring unit 33, a refractive index and a spectrum are exemplified.In the present embodiment, an example will be described in which the property measuring unit 33 measures the refractive index of the depolymerization material such as EG in which the depolymerized product such as BHET is dissolved.

[0048] The refractive index measured by the property measuring unit 33 is provided to a progress monitoring unit 37, which is constituted by a computer or a processor. The progress monitoring unit 37 monitors the progress of the depolymerization reaction in the depolymerization reaction vessel 300 (specifically, the vessel main body 31) based on the optical properties and other properties, such as the refractive index of the depolymerization material such as EG, measured by the property measuring unit 33.

[0049] Fig. 5A and Fig. 5B show examples of monitoring progress of the depolymerization reaction by the progress monitoring unit 37. As in Fig. 5A, there is a correlation, such as a proportionality relationship, between the refractive index measured by the property measuring unit 33 and the concentration of the depolymerized product, such as BHET, in the depolymerization material, such as EG, which is a measurement target (points (◯) in Fig. 5A are examples of actual measured values). As described above, in the reaction vessel 300 for depolymerization (specifically, the vessel main body 31), PET is decomposed by EG as the depolymerization material, and BHET as the depolymerized product is obtained. Therefore, the concentration of BHET represents the progress of the depolymerization reaction of PET. That is, the progress monitoring unit 37 can detect the progress of the depolymerization reaction of the polymer such as PET based on the concentration of the depolymerized product such as BHET, which is obtained based on the correlation as shown in Fig. 5A, is identified from the refractive index measured by the property measuring unit 33. As shown in Fig. 5B, for example, the progress monitoring unit 37 obtains the total amount of BHET produced in the depolymerization reaction vessel 300 based on the concentration of BHET obtained from Fig. 5A and expresses the quantity as a time-dependent change in relation to a reaction time (dots (◯) in Fig. 5B are examples of actual measured values). The monitoring result of the progress monitoring unit 37 as shown in Fig. 5A and Fig. 5B, controls for controlling the chemical recycling molding system and the chemical recycling device 100 in Fig. 1 or may be displayed on a management screen or an operation screen that can be seen by managers or operators.

[0050] The property measuring unit 33 measures non-optical properties of a depolymerization material, such as EG, in which a depolymerized product, such as BHET, is dissolved. For example, the property measuring unit 33 can measure electrical properties of a depolymerization material, such as EG, in which a depolymerized product, such as BHET, is dissolved in the depolymerization reaction vessel 300. In this case, instead of the optical property measuring unit 33 in Fig. 4, a property measuring unit is provided that includes an electrode that electrically interacts (e.g., comes into contact) with the depolymerization material, such as EG, in the depolymerization material flow section 32. Furthermore, a method of the property measuring unit 33 is not limited as long as it can measure the characteristics without removing the depolymerization material, such as EG, from the depolymerization material flow section 32 (depolymerization reaction vessel 300).

[0051] Furthermore, in a case where a polymer such as PET remaining in the depolymerization material such as EG in the container main body 31 without dissolving does not hinder the measurement, the property measuring unit 33 may be provided instead of the depolymerization material flow section 32 in connection with the container main body 31. For the optical property measuring unit 33 as shown in Fig. 4, however, it is preferable that the property measuring unit 33 is provided in the depolymerization material flow section 32 outside the container main body 31, and it is further preferable that an intrusion prevention unit 34 described below is provided because the remaining polymer such as PET has an undesirable effect such as diffuse reflection on the measuring light.

[0052] The penetration prevention unit 34 includes a first filter 341 provided on the one end 321 side of the tubular depolymerization material flow section 32, and a second filter 342 provided on the other end 322 side of the tubular depolymerization material flow section 32. The first filter 341 and the second filter 342 prevent insoluble material that is not dissolved in the depolymerization material, such as EG, from penetrating from the container main body 31 into the depolymerization material flow section 32. As described above, examples of the insoluble material that is not dissolved in the depolymerization material, such as EG, include polyesters or polymers, such as PET, which are reaction products of the depolymerization reaction, and oligomers produced by partial depolymerization of the polyesters or polymers.In this way, the insoluble material that may hinder the optical measurement of the property measuring unit 33 in the depolymerization material flow section 32 can be effectively removed by the first filter 341 and / or the second filter 342.

[0053] The direction switching unit 35 is configured to include a backwash pump or the like, which can switch a flow direction of the depolymerization material, such as EG, in the tubular depolymerization material flow section 32 between a first direction from one end 321 to the other end 322 and a second direction from the other end 322 to the one end 321 to prevent clogging of the first filter 341 and / or the second filter 342. By allowing the direction switching unit 35 to flow the depolymerization material, such as EG, in the first direction, the insoluble material collected by the second filter 342 at the other end 322 is returned to the container main body 31, and clogging of the second filter 342 is eliminated.Furthermore, by the direction switching unit 35 flowing the depolymerization material such as EG in the second direction, the insoluble material collected by the first filter 341 at one end 321 is returned to the container main body 31, and clogging of the first filter 341 is eliminated. To prevent clogging of both the first filter 341 and the second filter 342, the direction switching unit 35 preferably iteratively or periodically switches the flow direction of the depolymerization material such as EG in the depolymerization material flow section 32 between the first direction and the second direction.

[0054] The backwash pump or the like constituting the direction switching unit 35 may operate before or during measurement by the property measuring unit 33, and may be stopped at other times. When the backwash pump or the like constituting the direction switching unit 35 operates, the depolymerization material, such as EG, which is the measurement target of the property measuring unit 33, is discharged from the tank main body 31 at one end 321 and the other end 322 of the depolymerization material flow section 32.In this case, the "old" depolymerization material originally present in the depolymerization material flow section 32 is discharged from the other of one end 321 and the other end 322 of the depolymerization material flow section 32 into the container main body 31, thus removing the clogging of the other of the first filter 341 and the second filter 342 provided therein. Then, the property measurement unit 33 can measure the "new" depolymerization material newly discharged from the container main body 31.

[0055] The cooling unit 36 ​​cools the depolymerization material, such as EG, in the tubular depolymerization material flow section 32. The optical properties and other properties, such as the refractive index, that can be measured by the property measuring unit 33 depend on the temperature of the depolymerization material, such as EG, which is a measurement target. Therefore, the cooling unit 36 ​​stabilizes the measurement accuracy of the property measuring unit 33 by cooling the depolymerization material, such as EG, to a predetermined temperature before measurement by the property measuring unit 33.As described above, the cooling unit 36 ​​preferably includes a first cooling unit 361 on the one end 321 side with respect to the property measuring unit 33 and a second cooling unit 362 on the other end 322 side with respect to the property measuring unit 33, because the depolymerization material such as EG can flow in either the first direction or the second direction in the depolymerization material flow section 32 due to the direction switching unit 35.

[0056] Instead of the cooling unit 36, a heating unit that heats the depolymerization material, such as EG, to a predetermined temperature may be provided. However, in general, components such as the sensor constituting the property measurement unit 33 often have a low operating temperature (e.g., 150°C or lower). Therefore, it may not be possible to measure the depolymerization material, such as EG, in the container main body 31, for example, between 180°C and 250°C as it is. Therefore, it is preferable that the cooling unit 36 ​​lowers the temperature of the depolymerization material, such as EG, to a measurable temperature (operating temperature) of the property measurement unit 33. As shown in Fig. As shown in Figure 4, the cooling unit 36 ​​provided at the front and rear (or top and bottom) of the property measuring unit 33 can cool the property measuring unit 33 itself. Furthermore, a temperature sensor (not shown) that measures the temperature of the depolymerization material, such as EG, facing the property measuring unit 33 can be provided. In this way, the cooling unit 36 ​​and / or the heating unit can be controlled so that the temperature measured by the temperature sensor approaches a predetermined temperature that can be measured by the property measuring unit 33.

[0057] According to the depolymerization reaction monitoring device 30 or the progress monitoring unit 37 according to the first embodiment as described above, the progress of the depolymerization reaction of the polyester or polymer in which the depolymerized product such as BHET, which is the product, is dissolved in the depolymerization material such as EG, which is a reaction product or catalyst, can be efficiently identified by measuring the properties of the depolymerization material such as EG by the property measuring unit 33 in the depolymerization reaction vessel 300 (depolymerization material flow section 32).Since it is not necessary to take out the depolymerization material such as EG, which is the measurement target, from the depolymerization reaction vessel 300 (the depolymerization material flow section 32), the progress of the depolymerization reaction can be identified in real time.

[0058] Fig. Figure 6 shows a second embodiment of the depolymerization reaction monitoring device 30 according to the present invention. The same components as those in the first embodiment in Fig. 4 are denoted by the same reference numerals, and overlapping description is omitted.

[0059] The depolymerization material flow section 32 is provided with a depolymerization material dilution unit 38, which further adds a depolymerization material, such as EG, to the depolymerization material, such as EG, in the depolymerization material flow section 32 to dilute the depolymerization material. The depolymerization material dilution unit 38 includes a diluting depolymerization material supply unit 381 that supplies a depolymerization material for dilution, such as EG, a dilution pipe 382 that connects the diluting depolymerization material supply unit 381 and the depolymerization material flow section 32, a dilution valve 383 provided in the dilution pipe 382, ​​and a first valve 384.which is provided on the one end 321 side with respect to a connecting portion of the depolymerization material flow section 32 with the dilution pipe 382 and the property measuring unit 33, and which is provided on the other end 322 side with respect to the first cooling unit 361, and a second valve 385 which is provided on the other end 322 side with respect to the connecting portion of the depolymerization material flow section 32 with the dilution pipe 382 and the property measuring unit 33 and on the one end 321 side with respect to the second cooling unit 362.

[0060] Fig. Figure 7 shows an example of dilution of a depolymerization material by a depolymerization material dilution unit 38. As also in Fig. As shown in Figure 5A, there is a correlation, such as a proportionality relationship, between the refractive index of the depolymerization material, such as EG, in which the depolymerized product, such as BHET, is dissolved, and the concentration of the depolymerized product, such as BHET, in the depolymerization material, such as EG. As shown in Fig. However, as shown in Figure 7 (before dilution), this correlation breaks down in a case where the concentration of BHET or the like exceeds a predetermined value A. For this reason, the progress monitoring unit 37 may not be able to correctly identify the concentration of BHET or the like from the refractive index measured by the property measuring unit 33.

[0061] Therefore, the depolymerization material dilution unit 38 additionally supplies the depolymerization material, such as EG, from the diluting depolymerization material supply unit 381 to the solution of BHET or the like, which has such a high concentration that it breaks the linearity of the measurement in the property measuring unit 33. As a result, the concentration of the depolymerized product, such as BHET, in the depolymerization material flow section 32 (between the first valve 384 and the second valve 385) decreases, and as shown in Fig. 7 (after dilution), the correlation or linearity seems to be maintained even in a high concentration range. That is, by reducing the concentration of the depolymerized product, such as BHET, in the depolymerization material flow section 32, the refractive index measured by the property measuring unit 33 falls within a linear range in Fig. 7. Then, the progress monitoring unit 37 can measure the original (undiluted) concentration of BHET or the like in the container main body 31 (concentration on the straight line “after dilution” in Fig. 7) accurately identify based on the refractive index normally measured in the linear range by the property measuring unit 33 and the amount of EG or the like used for dilution by the dilution depolymerization material supply unit 381 (adjusted by the dilution valve 383 as described later).

[0062] The diluting depolymerization material supply unit 381 may supply a depolymerization material such as EG supplied from the depolymerization material supply unit 310, the depolymerization reaction tank 300, the polymerization reaction tank 400, the by-product removal device 500, and the like. Fig. 1 as a diluting depolymerization material. Alternatively, the depolymerization material, such as EG, that is not used in the main processes of the chemical recycling device 100 in the depolymerization material supply unit 310, the depolymerization reaction tank 300, the polymerization reaction tank 400, the by-product removal device 500, and the like may be used as the diluting depolymerization material. The diluting depolymerization material may contain impurities as long as it contains a depolymerization material, such as EG, as a main component.It is preferable that such impurities do not adversely affect the depolymerization reaction and / or repolymerization reaction, property measurement by the property measuring unit 33, progress monitoring by the progress monitoring unit 37, removal of by-product by the by-product removing device 500, or the like.

[0063] In order to improve the property measuring unit 33 in a case where the above-described dilution unit 38 for depolymerization material is used, various types of valves are provided, such as the dilution valve 383, the first valve 384, and the second valve 385. The opening and closing operations of the respective valves will be explained below with reference to a flowchart of a specific example of the measuring method shown in Fig. 8. When describing the flowchart, "S" means a step or process.

[0064] At S1, at the start of the measurement, it is assumed that the first valve 384 and the second valve 385 are open, and the dilution valve 383 is closed. At S2, a backwash pump or the like constituting the direction switching unit 35 operates, and the depolymerization material, such as EG, which is a measurement target, is taken out of the tank main body 31 to the depolymerization material flow section 32. At this time, as described above, the first cooling unit 361 and / or the second cooling unit 362 cool the taken-in depolymerization material, such as EG, to a predetermined measurable temperature of the property measuring unit 33.As a result, the depolymerization material, such as EG, cooled by the first cooling unit 361 and / or the second cooling unit 362 enters a space between the first valve 384 and the second valve 385 in the open state at S1. At S3, the first valve 384 and the second valve 385 are switched to the closed state. As a result, a closed space is temporarily formed between the first valve 384 and the second valve 385, and the total amount of BHET or the like in the closed space is determined.

[0065] At S4, the property measuring unit 33 performs primary measurement of a refractive index of the depolymerization material, such as EG, in the closed space formed at S3. At S5, it is determined whether the refractive index measured at S4 is a Fig. 7. In a case where "No" is determined at S5, the refractive index measured at S4 falls within a linear range equal to or less than the saturation threshold B, and is therefore used as a measurement result by the property measurement unit 33 at S6 as it is. At S7, the progress monitoring unit 37 calculates the concentration of the depolymerized product, such as BHET, based on the refractive index measurement result obtained at S6.

[0066] In a case where "Yes" is determined at S5, even if the process proceeds to S6 and S7, the correct concentration of the depolymerized product, such as BHET, cannot be obtained because the refractive index measured at S4 deviates from the linear range of the property measuring unit 33. Therefore, at S8, the dilution valve 383 is switched to the open state. At the subsequent S8(2), the second valve 385 is switched to the open state to supply EG for dilution to the property measuring unit 33. Then, at S9, the backwash pump or the like constituting the direction switching unit 35 operates, and the EG for dilution is supplied from the dilution depolymerization material supply unit 381 to the space between the first valve 384 and the second valve 385 through the dilution valve 383 in the open state.The amount of EG or the like used for dilution at S9 is measured by a flow rate sensor (not shown) provided in the dilution valve 383 or the like. At S10, the dilution valve 383 is switched to the closed state, and at S10(2), the second valve 385 is switched to the closed state. In this way, the closed space between the first valve 384 and the second valve 385 is re-established.

[0067] At S11, the property measuring unit 33 performs secondary measurement of a refractive index of the depolymerization material, such as EG, in the closed space formed at S3 and S10(2), and the process returns to S5. In a case where "No" is determined at S5, the refractive index after dilution with EG measured at S11 falls within a linear range equal to or smaller than the saturation threshold B, and is therefore used as a measurement result by the property measuring unit 33 at S6 as it is. At S7, the progress monitoring unit 37 calculates the original (undiluted) concentration of BHET or the like in the container main body 31 (concentration on the straight line "after dilution" in Fig. 7) Based on the secondary measurement result of the refractive index within the linear range obtained at S11 and the amount of EG or the like used for dilution at S9. That is, as described above, the dilution valve 383, the first valve 384, and the second valve 385 can appropriately control the amount of the depolymerization material, such as EG, entering the closed space (space defined by the three valves) formed at S3 by the container main body 31 and the dilution-depolymerization material supply unit 381. Therefore, the progress monitoring unit 37 can calculate the concentration of BHET or the like in the container main body 31 while identifying a quantitative effect of dilution by the depolymerization material dilution unit 38.

[0068] If S5 determines "Yes," the process proceeds to S8 through S11, and the dilution at S9 and the secondary measurement at S11 are repeated until S5 determines "No," that is, until the secondary measurement result of the refractive index at S11 falls within the linear range of the saturation threshold B or less. At S7, at the end of the measurement, the first valve 384, the second valve 385, and the dilution valve 383 are in the closed state.

[0069] Not only is the amount of EG for dilution or the like supplied from the dilution-depolymerization material supply unit 381 controlled by the dilution valve 383 or the like, but also the temperature thereof can be controlled. For example, by supplying the temperature-controlled EG for dilution or the like at S9 to the closed space formed at S3, the EG or the like in the closed space can be cooled to a predetermined measurable temperature of the property measuring unit 33. In this way, at least part of the function of the cooling unit 36 ​​can be realized by the EG for dilution or the like supplied from the dilution-depolymerization material supply unit 381. In this case, at least part of the first cooling unit 361 and the second cooling unit 362 may be Fig. 6 is not provided for.

[0070] Fig. Figure 9 shows a third embodiment of the depolymerization reaction monitoring device 30 according to the present invention. The same components as those in the first embodiment in Fig. 4 and / or the second embodiment in Fig. 6 are denoted by the same reference numerals, and overlapping description is omitted.

[0071] An extraction unit 39 is provided that can extract a designated amount of the depolymerization material, such as EG, flowing within the depolymerization material flow section 32. The extraction unit 39 includes, for example, a syringe pump 391 and an extraction valve 392. The syringe pump 391 extracts, takes in, or discharges a depolymerization material, such as EG, in accordance with a position of a movable piston housed in the syringe pump 391. The extraction valve 392 is provided between the main body of the tubular depolymerization material flow section 32 and the syringe pump 391. The extraction unit 39 may include another type of pump instead of the syringe pump 391. For example, a gear pump, a suction pump, a piston pump or a vane pump can be provided in the extraction unit 39 instead of the syringe pump 391.

[0072] The property measurement unit 33 is provided in the syringe pump 391. Specifically, as schematically shown in the drawings, the above-described optical measurement is performed through a window 333 provided in the syringe pump 391 (the light source 331 and the light receiving unit 332 are not shown). The property measurement unit 33 measures the property of the depolymerization material, such as EG, extracted by the extraction unit 39 (syringe pump 391).

[0073] As in the second embodiment in Fig. 6, the depolymerization material flow section 32 is provided with a depolymerization material dilution unit 38, which further adds a depolymerization material such as EG to the depolymerization material extracted by the extraction unit 39 (the syringe pump 391) to dilute the depolymerization material. The property measurement unit 33 measures the properties of the depolymerization material such as EG diluted by the depolymerization material dilution unit 38.

[0074] Fig. Figure 10 is a flowchart of a specific example of a measurement procedure. The same steps or processes as in Fig. 8 in the second embodiment are denoted by the same reference numerals, and overlapping description is omitted.

[0075] At S1, at the start of measurement, it is assumed that the extraction valve 392 is in an open state and the dilution valve 383 is in a closed state. At S2, a backwash pump or the like constituting the direction switching unit 35 operates, and the depolymerization material such as EG, which is a measurement target, is taken out from the container main body 31 to the depolymerization material flow section 32. At S12, the extraction unit 39 extracts the depolymerization material such as EG, which was taken into the depolymerization material flow section 32 at S2, by a designated amount (first designated amount) (primary extraction). At S3, the extraction valve 392 is switched to the closed state. As a result, the first designated amount of the depolymerization material such as EG is secured in the extraction unit 39 (the syringe pump 391).

[0076] At S4, the property measurement unit 33 performs primary measurement of a refractive index of the first designated amount of the depolymerization material, such as EG, secured in the extraction unit 39 (the syringe pump 391) at S3. At S5, it is determined whether the refractive index measured at S4 is a Fig. 7. In a case where "No" is determined at S5, the refractive index measured at S4 falls within a linear range equal to or less than the saturation threshold B, and is therefore used as a measurement result by the property measurement unit 33 at S6 as it is. At S7, the progress monitoring unit 37 calculates the concentration of the depolymerized product, such as BHET, based on the refractive index measurement result obtained at S6.

[0077] In a case where "Yes" is determined at S5, even if the process proceeds to S6 and S7, the correct concentration of the depolymerized product, such as BHET, cannot be obtained because the refractive index measured at S4 deviates from the linear range of the property measuring unit 33. Therefore, at S8, the dilution valve 383 is switched to the open state. At S13, the extraction unit 39 extracts a designated amount (second designated amount) of EG for dilution or the like from the dilution depolymerization material supply unit 381 (secondary extraction) through the dilution valve 383 in the open state. Then, at S9, the EG or the like in the extraction unit 39 (the syringe pump 391) is diluted with the EG extracted at S13 for dilution or the like. At S10, the dilution valve 383 is switched to the closed state.As a result, in addition to the first designated amount of the depolymerization material, such as EG (in which the depolymerized product, such as BHET, is dissolved), which is mainly extracted at S12, the second designated amount of the depolymerization material, such as EG (in which the depolymerized product, such as BHET, is not dissolved), which is secondarily extracted at S13, is secured within the extraction unit 39 (the syringe pump 391).

[0078] At S11, the property measuring unit 33 performs the secondary measurement of the refractive index of the depolymerization material, such as EG, secured within the extraction unit 39 (the syringe pump 391) at S3 and S10, with the first designated amount and the second designated amount, and the process returns to S5. In a case where "No" is determined in S5, the refractive index after dilution with EG measured at S11 falls within a linear range equal to or smaller than the saturation threshold B and is therefore used as a measurement result by the property measuring unit 33 at S6 as it is. At S7, the progress monitoring unit 37 calculates the original (undiluted) concentration of BHET or the like in the container main body 31 (the concentration on the straight line "after dilution" in Fig.7) Based on the secondary measurement result of the refractive index within the linear range obtained at S11, the first designated amount (obtained from the syringe pump 391 or the extraction valve 392) primarily extracted at S12 and the second designated amount (obtained from the syringe pump 391 or the dilution valve 383) secondarily extracted at S13. That is, as described above, the syringe pump 391, the extraction valve 392, and the dilution valve 383 can each control the amount of the depolymerization material, such as EG, entering the extraction unit 39 (the syringe pump 391) from the container main body 31 (or the depolymerization material flow section 32) and the dilution depolymerization material supply unit 381.Therefore, the progress monitoring unit 37 can calculate the concentration of BHET or the like in the container main body 31 while identifying a quantitative effect of dilution by the depolymerization material dilution unit 38.

[0079] In a case where "Yes" is determined at S5, the process proceeds to S8 to S11 again, and the secondary extraction at S13, the dilution at S9, and the secondary measurement at S11 are repeated until "No" is determined at S5, that is, until the secondary measurement result of the refractive index at S11 falls within the linear range of the saturation threshold B or less. At S7 at the end of the measurement, the extraction valve 392 and the dilution valve 383 are in the closed state.

[0080] The present invention has been described above based on the embodiment. Various modification examples are possible by combining each component and process in the embodiment as an example, and it will be apparent to those skilled in the art that such modification examples fall within the scope of the present invention.

[0081] The configurations, effects, and functions of each device and method described in the embodiment can be realized by hardware resources or software resources, or by the cooperative operation of hardware resources and software resources. For example, a processor, a ROM, a RAM, and various integrated circuits can be used as the hardware resources. For example, programs such as an operating system and applications can be used as the software resources. Industrial applicability

[0082] The present invention relates to a depolymerization reaction monitoring device and the like. List of reference symbols 1 injection molding machine 30 Depolymerization reaction monitoring device 31 Container main body 32 Flow section for depolymerization material 33 Property measurement unit 34 Intrusion Prevention Unit 35 Directional switching unit 36 Cooling unit 37 Progress Monitoring Unit 38 Dilution unit for depolymerization material 39 Extraction unit 100 chemical recycling device 300 reaction vessels for depolymerization 321 an end 322 other end 331 light source 332 Light receiving unit 333 windows 341 first filter 342 second filter 361 first cooling unit 362 second cooling unit 381 Dilution Depolymerization Material Supply Unit 382 Dilution tube 383 Dilution valve 384 first valve 385 second valve 391 syringe pump 392 Extraction valve QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2016-153176

[0002] JP 2022-27158 [0002, 0034] JP 2925599

[0029] JP 2020-130985

[0034]

Claims

[1] Depolymerization reaction monitoring device comprising: a depolymerization reaction vessel that causes a depolymerization reaction in which a polyester is decomposed into a depolymerized product by using a depolymerization material; a property measuring unit that measures a property of the depolymerization material in which the depolymerized product is dissolved in the depolymerization reaction vessel; and a progress monitoring unit that monitors the progress of the depolymerization reaction based on the property of the depolymerization material measured by the property measuring unit. [2] Depolymerization reaction monitoring device according to claim 1, wherein the reaction vessel for depolymerization includes a vessel main body which causes the depolymerization reaction, and a depolymerization material flow section through which the depolymerization material flows between the vessel main body and the depolymerization material flow section, and the property measuring unit measures the property of the depolymerization material in the depolymerization material flow section. [3] The depolymerization reaction monitoring device according to claim 2, wherein one end and the other end of the depolymerization material flow section are connected to different locations of the container main body. [4] The depolymerization reaction monitoring device according to claim 3, wherein an intrusion preventing unit that prevents insoluble matter not dissolved in the depolymerization material from intruding from the container main body into the depolymerization material flow section is provided on a side of one end and a side of the other end of the depolymerization material flow section. [5] The depolymerization reaction monitoring device according to claim 4, further comprising: a direction switching unit configured to switch a flow direction of the depolymerization material in the depolymerization material flow section between a first direction from one end to the other end and a second direction from the other end to the one end. [6] Depolymerization reaction monitoring device according to any one of claims 2 to 5, further comprising: a depolymerization material dilution unit that further adds the depolymerization material to the depolymerization material in the depolymerization material flow section to dilute the depolymerization material. [7] Depolymerization reaction monitoring device according to one of claims 2 to 5, wherein the flow section for depolymerization material contains an extraction unit configured to extract a designated amount from the flowing depolymerization material, and the property measuring unit measures the property of the depolymerization material extracted by the extraction unit. [8] The depolymerization reaction monitoring device according to claim 7, further comprising: a depolymerization material dilution unit which further adds the depolymerization material to the depolymerization material extracted by the extraction unit to dilute the depolymerization material, wherein the property measuring unit measures the property of the depolymerization material diluted by the depolymerization material diluting unit. [9] Depolymerization reaction monitoring device according to any one of claims 2 to 5, further comprising: a cooling unit that cools the depolymerization material in the depolymerization material flow section. [10] The depolymerization reaction monitoring device according to any one of claims 1 to 5, wherein the property measuring unit measures an optical property of the depolymerization material in which the depolymerized product is dissolved at the depolymerization reaction vessel. [11] The depolymerization reaction monitoring device according to claim 10, wherein the optical property is a refractive index. [12] The depolymerization reaction monitoring device according to any one of claims 1 to 5, wherein the property measuring unit measures an electrical property of the depolymerization material in which the depolymerized product is dissolved at the depolymerization reaction vessel. [13] Depolymerization reaction monitoring device according to one of claims 1 to 5, wherein the polyester is polyethylene terephthalate, the depolymerization material is ethylene glycol, and the depolymerized product is bis(2-hydroxyethyl) terephthalate. [14] Depolymerization reaction monitoring method comprising: Causing a depolymerization reaction in which a polyester is decomposed into a depolymerized product by using a depolymerization material in a depolymerization reaction vessel; Measuring a property of the depolymerization material in which the depolymerized product is dissolved in the depolymerization reaction vessel; and Monitoring the progress of the depolymerization reaction based on the measured property of the depolymerization material. [15] Depolymerization reaction monitoring program that causes a computer to execute: Causing a depolymerization reaction in which a polyester is decomposed into a depolymerized product by using a depolymerization material in a depolymerization reaction vessel; Measuring a property of the depolymerization material in which the depolymerized product is dissolved in the depolymerization reaction vessel; and Monitoring the progress of the depolymerization reaction based on the measured property of the depolymerization material.

Images