Cleaning device, separation system and cleaning method

Abstract

To make it possible to remove foreign matter stably.SOLUTION: A cleaning device includes: a container for storing filters with solidified polyester and impurities attached thereto; a first fluid supply part that supplies a first fluid to the container, the first fluid removing solidified polyester from the filter; and a second fluid supply part that supplies a second fluid to the container after the first fluid supply part supplies the first fluid to the container, the second fluid removing impurities from the filter.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a cleaning apparatus, a separation system, and a cleaning method. [Background technology]

[0002] For example, a technique for separating impurities from polyester in order to recycle polyester is known. Patent Document 1 describes that polyethylene terephthalate (PET) waste is introduced into ethylene glycol (EG) and depolymerized to obtain bis(β-hydroxyethyl) terephthalate (BHET), and that foreign matter other than PET is removed by a filter during or after the depolymerization reaction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4065659 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the filter of the filter is clogged with foreign matter during the depolymerization reaction of PET, the depolymerization reaction must be stopped, making it difficult to stably remove the foreign matter.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a cleaning device, a separation system, and a cleaning method that can stably remove foreign matter. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the objectives, the cleaning device of the present disclosure includes a storage container that stores a filter to which solidified polyester and impurities are attached, a first fluid supply unit that supplies a first fluid to the storage container that removes the solidified polyester from the filter, and a second fluid supply unit that supplies a second fluid to the storage container that removes the impurities from the filter after the first fluid supply unit has supplied the first fluid to the storage container.

[0007] In order to solve the above-mentioned problems and achieve the objectives, the separation system according to the present disclosure comprises a separation system main body that monomerizes polyester contained in a polyester raw material to produce a monomer, and a cleaning device that cleans the filter of the separation system main body.

[0008] In order to solve the above-mentioned problems and achieve the objectives, the cleaning method of the present disclosure is a cleaning method for cleaning a filter having solidified polyester and impurities attached thereto, and includes the steps of placing the filter in a storage container, supplying a first fluid to the storage container that removes the solidified polyester from the filter, and, after the first fluid supply unit supplies the first fluid to the storage container, supplying a second fluid to the storage container that removes the impurities from the filter. [Effects of the Invention]

[0009] According to the present disclosure, foreign matter can be stably removed. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a polyester recycling process according to the present embodiment. [Figure 2] FIG. 2 is a schematic diagram of the separation system according to the first embodiment. [Figure 3] FIG. 3 is a schematic diagram showing the configuration of the filter. [Figure 4] FIG. 4 is a schematic top view of the filter. [Figure 5]FIG. 5 is a schematic diagram of the cleaning device according to the first embodiment. [Figure 6] FIG. 6 is a diagram illustrating control of the cleaning device according to the first embodiment. [Figure 7] FIG. 7 is a partial schematic diagram of a separation system according to the second embodiment. [Figure 8] FIG. 8 is a schematic diagram of a cleaning device according to another example. [Figure 9] FIG. 9 is a schematic diagram of a cleaning device according to another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to these embodiments, and when there are multiple embodiments, the present invention also includes configurations in which the respective embodiments are combined.

[0012] (First embodiment) (Recycling process) FIG. 1 is a schematic diagram of a polyester recycling process according to this embodiment. In this embodiment, polyester raw material Pm is depolymerized to form monomers, and the monomers are then repolymerized to recycle (regenerate) polyester raw material Pm. Specifically, as shown in FIG. 1, polyester raw material Pm is flaked (step S100), the flaked polyester raw material Pm is dissolved in carboxylic acid-derived monomer D to produce a polyester solution (step S101), foreign matter is removed from the solution (step S102), the solution from which the foreign matter has been removed is mixed with reaction solvent M for depolymerization (step S103), the depolymerized polyester monomers are purified (separated) to produce carboxylic acid-derived monomer D and alcohol component monomer E (step S104), monomer D is hydrolyzed to separate reaction solvent M (step S106), and monomer F, produced by hydrolysis of monomer D, is polymerized with monomer E (step S108), thereby regenerating polyester raw material Pm. In addition, in the recycling process employing the separation system 1 of this embodiment, the flaking step S100 may be omitted, or the repolymerization step as in step S108 may not be performed, and only the process of recovering monomers D and E shown in step S102 and step S104, and monomer F shown in step S106 may be performed.

[0013] (Polyester raw material) In this embodiment, the polyester raw material Pm to be depolymerized is a substance containing polyester. The polyester raw material Pm is not particularly limited, but examples include waste products such as polyethylene terephthalate (PET), polyethylene butylene terephthalate (PEBT), polybutylene terephthalate (PBT), polycyclohexane dimethyl terephthalate (PCT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), and polycarbonate (PC). The polyester raw material Pm is not limited to those containing only polyester components, and may also contain components (impurities) other than polyester components. Examples of components other than polyester contained in the polyester raw material Pm include plastics other than polyester, such as polyethylene, polystyrene, polypropylene, and polyvinyl chloride, metals, dyes, pigments, and polymerization catalysts. Examples of the polyester raw material Pm include clothing in which polyester and other components are knitted into fibers. Hereinafter, components other than polyester contained in the polyester raw material Pm are referred to as impurities R.

[0014] (Reaction solvent) The reaction solvent M is a solvent that reacts with the polyester to depolymerize the polyester, and may be, for example, at least one of methanol, ethanol, water, and ethylene glycol.

[0015] (Carboxylic acid-derived monomers) The carboxylic acid-derived monomer D is a monomer having a carboxyl group produced by depolymerization of a polyester. Monomer D may be, for example, dimethyl carboxylate or diethyl carboxylate. Furthermore, monomer D is preferably a terephthalic acid monomer, such as dimethyl terephthalate (DMT).

[0016] (Alcohol component monomer) The alcohol component monomer E is an alcohol component monomer produced by the depolymerization reaction of the polyester. The alcohol component monomer E may be, for example, a dihydroxy compound (dihydric alcohol), or more specifically, ethylene glycol (EG).

[0017] In the following, an example will be described in which the polyester is PET, the reaction solvent M is methanol, the monomer D is DMT, and the monomer E is EG.

[0018] (separate system) FIG. 2 is a schematic diagram of a separation system according to a first embodiment. The separation system 1 according to the first embodiment is a system for monomerizing polyester contained in a polyester raw material Pm to produce monomers D and E. As shown in FIG. 1, the separation system 1 includes a raw material storage section 10, a dissolving section 12, a solid-liquid separation section 13, a storage section 20, a removal section 26, a reaction solvent storage section 14, a reaction section 16, a separation section 18, a control section 30, and a cleaning apparatus 100. The cleaning apparatus 100 may be located on a different site from or on the same site as the separation system main body, which includes the raw material storage section 10, the dissolving section 12, the solid-liquid separation section 13, the storage section 20, the removal section 26, the reaction solvent storage section 14, the reaction section 16, the separation section 18, and the control section 30, which are other components of the separation system 1.

[0019] (Raw material storage section) The raw material storage section 10 is a tank into which the polyester raw material Pm is introduced and stored. In this embodiment, the raw material storage section 10 stores flaked polyester raw material Pm, but the shape and size of the polyester raw material Pm may be arbitrary. The raw material storage section 10 is connected to the dissolving section 12 via an inlet pipe 10a. The polyester raw material Pm in the raw material storage section 10 is supplied to the dissolving section 12 through the inlet pipe 10a. The inlet pipe 10a is provided with an adjustment section 10b that adjusts the amount of polyester raw material Pm supplied from the raw material storage section 10 to the dissolving section 12. The adjustment section 10b is, for example, an on-off valve. When open, the adjustment section 10b allows the polyester raw material Pm in the raw material storage section 10 to be supplied to the dissolving section 12, and when closed, the adjustment section 10b stops the supply of the polyester raw material Pm in the raw material storage section 10 to the dissolving section 12. However, the adjustment section 10b is not limited to an on-off valve and may be any mechanism that can adjust the supply of the polyester raw material Pm to the dissolving section 12. The polyester raw material Pm may be supplied directly to the dissolving section 12 without passing through the raw material reservoir 10, the introduction pipe 10a, and the adjusting section 10b.

[0020] (melting part) The dissolving unit 12 is a tank that stores a dissolving liquid Pd. The dissolving liquid Pd is a solution produced by mixing a polyester raw material Pm and a monomer D. Here, the polyester contained in the polyester raw material Pm dissolves in the monomer D, but impurities R, which are components other than the polyester contained in the polyester raw material Pm, remain without dissolving in the monomer D. Therefore, it can be said that the dissolving liquid Pd contains a polyester solution P in which the polyester contained in the polyester raw material Pm is dissolved in the monomer D, and the impurities R contained in the polyester raw material Pm.

[0021] Monomer D and polyester raw material Pm are supplied to dissolution section 12. In dissolution section 12, the polyester contained in polyester raw material Pm dissolves in monomer D, while impurities R remain without dissolving in monomer D, thereby producing polyester solution P and solution Pd containing impurities R. By dissolving polyester in monomer D in this way, viscosity can be reduced and fluidity can be improved, allowing polyester to be easily introduced into reaction section 16. Note that the polyester solution P is not limited to one in which all of the polyester is dissolved in monomer D; at least a portion of the polyester may be insoluble in monomer D. Furthermore, if there is a component soluble in monomer D among the components other than polyester contained in polyester raw material Pm, the polyester solution P may also contain that component dissolved in monomer D.

[0022] In this embodiment, the dissolving section 12 is provided with a heating section 12A. The heating section 12A heats the interior of the dissolving section 12, thereby heating the monomer D and polyester raw material Pm supplied to the dissolving section 12 to a predetermined temperature. The predetermined temperature is a temperature at which the polyester can be dissolved in the monomer D. By heating at this predetermined temperature, the polyester contained in the polyester raw material Pm can be properly dissolved in the monomer D. The predetermined temperature is preferably 140°C or higher and 300°C or lower, more preferably 160°C or higher and 280°C or lower, and even more preferably 190°C or higher and 250°C or lower. Note that the impurities R also contain a component that melts when heated to a predetermined temperature (a temperature at which the polyester can be dissolved in the monomer D). Therefore, if the impurities R contain a component that melts when heated to a predetermined temperature, the impurities R will be contained in the solution Pd in ​​a partially melted state. In this embodiment, the heating section 12A is provided in the dissolving section 12, but the location at which the heating section 12A is provided is not limited thereto and is arbitrary.

[0023] (Solid-liquid separation section) The solid-liquid separation section 13 is disposed in the dissolving section 12. The solid-liquid separation section 13 collects solid impurities R contained in the dissolving solution Pd stored in the dissolving section 12 and separates the solid impurities R from the dissolving solution Pd. The solid-liquid separation section 13 is a mesh-shaped filter through which liquid passes and collects solids. In this embodiment, the solid-liquid separation section 13 has a container shape with an open top and is disposed at a predetermined distance from the side and bottom of the dissolving section 12. The solid-liquid separation section 13 is disposed downstream of the inlet pipe 10a and the supply pipe through which the monomer D is supplied, and upstream of the inlet pipe 12a that supplies the dissolving solution Pd from the dissolving section 12 to the downstream storage section 20. The dissolving solution Pd flowing into the inlet pipe 12a from the dissolving section 12 passes through the solid-liquid separation section 13. As a result, the solid-liquid separation section 13 collects solids larger than the mesh opening diameter. The solid-liquid separation section 13 preferably has a mesh opening diameter of 1 mm or more and 50 mm or less.

[0024] In this embodiment, the solid-liquid separation unit 13 uses a method of filtering using a mesh filter, but is not limited to this. The solid-liquid separation unit 13 may separate the impurities R from the solution Pd by centrifugal separation, which stirs the inside of the dissolving unit 12 around a predetermined axis and moves the impurities radially outward from the rotating shaft. The solid-liquid separation unit 13 is not limited to filtration or centrifugal separation as long as it can separate solid impurities of a predetermined size or larger from the solution Pd.

[0025] The foreign matter recovery unit 50 recovers solid impurities collected by the solid-liquid separation unit 13. The foreign matter recovery unit 50, for example, moves the filter of the solid-liquid separation unit 13 to recover the adhering impurities. The solid-liquid separation unit 13 may also include a press device that presses impurities adhering to a mesh-shaped filter against the filter and squeezes out the solution Pd contained in the impurities. By squeezing the solution with the press device before the foreign matter recovery unit 50 recovers the impurities, more solution Pd can be left in the separation system 1. When the solid-liquid separation unit 13 separates by centrifugation, the foreign matter recovery unit 50 recovers the impurities from the area where the impurities accumulate during centrifugation.

[0026] (Storage section) The reservoir 20 is a tank in which the dissolving liquid Pd is stored. The reservoir 20 is connected to the dissolving unit 12 via an inlet pipe 12a. The dissolving liquid Pd in ​​the dissolving unit 12 is supplied to the reservoir 20 through the inlet pipe 12a. The inlet pipe 12a is provided with an adjustment unit 12a1 that adjusts the amount of dissolving liquid Pd supplied from the dissolving unit 12 to the reservoir 20. The adjustment unit 12a1 is, for example, an on-off valve. When in an open state, the adjustment unit 12a1 allows the dissolving liquid Pd in ​​the dissolving unit 12 to be supplied to the reservoir 20, and when in a closed state, the adjustment unit 12a1 stops the supply of the dissolving liquid Pd in ​​the dissolving unit 12 to the reservoir 20. However, the adjustment unit 12a1 is not limited to being an on-off valve and may be any mechanism that can adjust the supply of the dissolving liquid Pd to the reservoir 20. In this embodiment, the reservoir 20 is connected to the dissolving section 12 via the introduction pipe 12a, but a temporary reservoir for temporarily storing the dissolving liquid Pd can also be provided between the dissolving section 12 and the reservoir 20.

[0027] In the storage section 20, the solution Pd is separated by gravity into the polyester solution P and impurities R. Here, the impurities R separated in the storage section 20 are impurities that were not recovered in the solid-liquid separation section 13 and moved to the storage section 20 together with the solution Pd. In this embodiment, the solution Pd stored in the storage section 20 is allowed to stand, whereby it is separated by gravity into the polyester solution P and the impurities R.

[0028] In this embodiment, the solution Pd stored in the storage section 20 is separated by gravity into a layer of first impurities R1, a layer of polyester solution P, and a layer of second impurities R2. The layer of first impurities R1 is formed vertically below the layer of polyester solution P. That is, the first impurities R1 are impurities R that do not dissolve in monomer D and have a higher specific gravity than the polyester solution P. The first impurities R1 settle within the polyester solution P in the storage section 20 to form the layer of first impurities R1. On the other hand, the layer of second impurities R2 is formed vertically above the layer of polyester solution P. That is, the second impurities R2 are impurities R that do not dissolve in monomer D and have a lower specific gravity than the polyester solution P. The second impurities R2 float up within the polyester solution P in the storage section 20 to form the layer of second impurities R2.

[0029] The solution Pd in ​​the reservoir 20 is maintained at a predetermined temperature or higher (a temperature at which the polyester can be dissolved in the monomer D). The first impurity R1 and the second impurity R2 are components of the impurities R that melt when heated to a predetermined temperature, and therefore exist in a molten state in the reservoir 20. The first impurity R1 and the second impurity R2 are, for example, plastics other than polyester (polyethylene, polystyrene, polypropylene, polyvinyl chloride, etc. other than polyester).

[0030] In this embodiment, the layer of the polyester solution P contains a third impurity R3. The third impurity R3 is a component of the impurities R that is insoluble in the monomer D and does not melt even at a predetermined temperature (the temperature at which the polyester is soluble in the monomer D). That is, the third impurity R3 is not separated from the polyester solution P even by gravity separation, and exists in the polyester solution P in an unmelted solid state. In this embodiment, the third impurity R3 is dispersed in the polyester solution P. The third impurity R3 is, for example, a dye, a pigment, or a polymerization catalyst.

[0031] A discharge pipe 20a is connected to the storage section 20. The discharge pipe 20a is a pipe for discharging the first impurities R1 separated into a lower layer below the polyester solution P from the storage section 20. The discharge pipe 20a is connected to a position in the storage section 20 where a layer of the first impurities R1 is formed, and in this embodiment, the discharge pipe 20a is connected to the bottom of the storage section 20. A first discharge section 22a is provided in the discharge pipe 20a. The first discharge section 22a is a mechanism for discharging the first impurities R1 in the storage section 20 from the storage section 20, and in this embodiment, is a pump.

[0032] A discharge pipe 20b is connected to the storage section 20. The discharge pipe 20b is a pipe for discharging the second impurities R2, which have separated into an upper layer above the polyester solution P, from the storage section 20. The discharge pipe 20b is connected to a position in the storage section 20 where a layer of the second impurities R2 is formed, and is connected vertically above the discharge pipe 20a. The storage section 20 is equipped with second discharge sections 22b1 and 22b2 that discharge the second impurities R2 in the storage section 20 from the storage section 20. The second discharge section 22b1 is a skimmer provided at the liquid surface of the polyester solution P, and collects (scrapes off) the second impurities R2 floating on the liquid surface of the polyester solution P. The second discharge section 22b2 is provided to the discharge pipe 20b and is a mechanism that discharges the second impurities R2 collected in the second discharge section 22b1 via the discharge pipe 20b, and is a pump in this embodiment. In this manner, in the example of this embodiment, second discharge parts 22b1 and 22b2 are provided as a mechanism for discharging the second impurity R2, but the configuration of the second discharge part for discharging the second impurity R2 is not limited to this and may be any configuration.

[0033] The first impurity R1 and the second impurity R2 separated from the polyester solution P in the storage section 20 are discharged to the outside of the storage section 20 by the first discharge section 22a and the second discharge sections 22b1, 22b2. This removes the first impurity R1 and the second impurity R2 from the polyester solution P. Hereinafter, when there is no need to distinguish between the first discharge section 22a and the second discharge sections 22b1, 22b2, they will be referred to as the discharge section 22. Note that in the above explanation, the impurities R included the first impurity R1 having a higher specific gravity than the polyester solution P and the second impurity R2 having a lower specific gravity than the polyester solution P, but this is not limited thereto, and the impurities R may include only one of the first impurity R1 and the second impurity R2.

[0034] An inlet pipe 20c is connected to the storage section 20. The inlet pipe 20c is a pipe for discharging the polyester solution P separated from the impurities R from the storage section 20. The inlet pipe 20c is connected to a position in the storage section 20 where a layer of the polyester solution P is formed, and in this embodiment, the inlet pipe 20c is connected to a position between the discharge pipes 20a and 20b in the vertical direction. The inlet pipe 20c is provided with an outlet 24. The outlet 24 is a mechanism for discharging the polyester solution P in the storage section 20 from the storage section 20, and in this embodiment, is a pump. In this embodiment, the inlet pipes 20c include an inlet pipe 20c1 connecting the storage section 20 to a filter 26a (described later), an inlet pipe 20c2 connecting the filter 26a to an adsorption tower 26b (described later), and an inlet pipe 20c3 connecting the adsorption tower 26b to the reaction section 16.

[0035] (Removal part) The removal unit 26 is a mechanism for removing the third impurity R3 contained in the polyester solution P from the polyester solution P. The removal unit 26 is connected to the storage unit 20, and removes the third impurity R3 present in the polyester solution P discharged from the storage unit 20 from the polyester solution P. In this embodiment, the removal unit 26 includes a filter 26a and an adsorption tower 26b.

[0036] (filter) The filter 26a is connected to the reservoir 20 via an inlet pipe 20c1. The polyester solution P discharged from the reservoir 20 is introduced into the filter 26a through the inlet pipe 20c1. The filter 26a uses a filter to collect solid components contained in the third impurity R3 of the polyester solution P. The structure of the filter 26a will be described later.

[0037] (Adsorption tower) The adsorption tower 26b is connected to the filter 26a via an inlet pipe 20c2. The polyester solution P discharged from the filter 26a (the polyester solution P after the solid components have been collected by the filter 26a) is introduced into the adsorption tower 26b through the inlet pipe 20c2. The adsorption tower 26b has a collection unit that collects the third impurity R3 contained in the polyester solution P. The collection unit of the adsorption tower 26b may be an adsorbent that adsorbs the third impurity R3 contained in the polyester solution P, or may be a filtration unit that collects the third impurity by filtration. That is, the adsorption tower 26b may collect the third impurity R3 by at least one of adsorption and filtration. The adsorbent stored in the adsorption tower 26b is preferably one that can adsorb the molecular skeleton of the third impurity R3 (e.g., a quinone group, an azo group, a heterocycle, or a benzene ring). The adsorbent is preferably, for example, activated carbon.

[0038] The adsorption tower 26b is connected to the reaction section 16, which will be described later, via an inlet pipe 20c3. That is, the polyester solution P from which the third impurity has been removed in the adsorption tower 26b is introduced into the reaction section 16 through the inlet pipe 20c3.

[0039] In this manner, the polyester solution P discharged from the reservoir 20 through the inlet pipe 20c1 is introduced into the filter 26a, where at least a portion of the third impurities R3 contained in the polyester solution P are collected by the filter 26a. The third impurities R3 collected by the filter 26a are discharged to the outside through a discharge pipe 26a1 connected to the filter 26a. In the example shown in FIG. 2, the discharge pipe 26a1 merges with the discharge pipe 20a, but it does not have to merge with the discharge pipe 20a. The polyester solution P from which at least a portion of the third impurities R3 have been removed by the filter 26a is discharged from the filter 26a and introduced into the adsorption tower 26b. In the adsorption tower 26b, the third impurities R3 remaining in the polyester solution P are adsorbed or filtered by the adsorption tower 26b and removed from the polyester solution P. The third impurities R3 adsorbed or filtered by the adsorption tower 26b are, for example, dyes or polymerization catalysts. The polyester solution P from which the third impurity R3 has been removed by the adsorption tower 26b is discharged from the adsorption tower 26b and introduced into the reaction section 16 through the introduction pipe 20c.

[0040] As described above, in this embodiment, a filter 26a and an adsorption tower 26b are provided as a mechanism for removing the third impurity R3 from the polyester solution P, but the configuration of the removal section 26 that discharges the third impurity R3 is not limited to this and may be any configuration.

[0041] (Reaction solvent storage section) The reaction solvent reservoir 14 is a tank into which the reaction solvent M is introduced and where the reaction solvent M is stored. The reaction solvent reservoir 14 is connected to the reaction section 16 via an inlet pipe 14a. The reaction solvent M in the reaction solvent reservoir 14 is supplied to the reaction section 16 through the inlet pipe 14a. More specifically, the inlet pipe 14a is provided with a heating and pressurizing section 14b that pressurizes and heats the reaction solvent M. The heating and pressurizing section 14b pressurizes and heats the reaction solvent M, thereby bringing the reaction solvent M into a supercritical state or a subcritical state (pressurized gas or pressurized liquid). The reaction section 16 is supplied with the reaction solvent M in a supercritical state or a subcritical state (pressurized gas or pressurized liquid).

[0042] (Reaction section) The reaction section 16 is a container into which the polyester solution P from which the impurities R have been separated in the storage section 20 and the reaction solvent M are introduced, and the polyester in the polyester solution P is depolymerized. The reaction section 16 includes a first reaction section 16A and a second reaction section 16B. Hereinafter, within the reaction section 16, the direction from the first reaction section 16A to the second reaction section 16B is referred to as direction Y1, and the direction opposite to direction Y1 (the direction from the second reaction section 16B to the first reaction section 16A) is referred to as direction Y2. In this embodiment, direction Y2 is the direction of gravity (vertically downward).

[0043] (First reaction section) The first reaction section 16A is formed within the reaction section 16. In this embodiment, the first reaction section 16A can be said to be a portion of the reaction section 16 that is filled with a filler. A known filler used in gas-liquid or liquid-liquid contactors can be used for the first reaction section 16A, such as a filler similar to that used in a contactor that brings heavy oil and water into contact to extract active ingredients. Specific examples of fillers include pipes made of stainless steel or the like, Raschig rings, Berl saddles, terrarettes, balls, and the like.

[0044] An inlet pipe 20c is connected to the first reaction section 16A. More specifically, an inlet 16C, which is an opening of the inlet pipe 20c through which the polyester solution P is introduced from the reservoir 20, is connected to the first reaction section 16A. The inlet 16C is connected to a surface 16A1 on the first direction Y1 side of the first reaction section 16A. The inlet pipe 20c is connected to the surface 16A1 so that the inlet 16C opens toward the second direction Y2, which is the opposite direction to the first direction Y1. In this manner, in this embodiment, the inlet 16C opening toward the second direction Y2 is connected to the surface 16A1 of the first reaction section 16A, but this is not limiting. For example, the inlet 16C does not have to be directly connected to the first reaction section 16A, and the inlet 16C opening toward the second direction Y2 may be connected to the first direction Y1 side of the surface 16A1 of the first reaction section 16A within the reaction section 16.

[0045] An inlet pipe 14a is connected to the reaction section 16. More specifically, an inlet 16D, which is an opening of the inlet pipe 14a through which the reaction solvent M is introduced from the reaction solvent reservoir 14, is connected to the reaction section 16. The inlet 16D is connected closer to the second direction Y2 than the surface 16A2 on the second direction D2 side of the first reaction section 16A. The inlet pipe 14a is connected closer to the second direction Y2 than the surface 16A2 so that the inlet 16D opens toward the first direction Y1 or from the side toward the center. In this embodiment, the inlet 16D, which opens toward the first direction Y1 or from the side toward the center, is connected closer to the second direction Y2 than the surface 16A2 of the first reaction section 16A. However, this is not limiting. For example, the inlet 16D may be directly connected to the first reaction section 16A or may be connected to the surface 16A2 of the first reaction section 16A.

[0046] In this embodiment, the inlet 16C through which the polyester solution P is introduced opens facing the second direction Y2, and the inlet 16D through which the reaction solvent M is introduced opens facing the first direction Y1 or from the side toward the center. Therefore, the polyester solution P and the reaction solvent M are introduced into the first reaction section 16A in directions facing each other.

[0047] The polyester solution P introduced into the first reaction section 16A through the inlet 16C moves in the second direction Y2 on the surface of the filler in the first reaction section 16A. Meanwhile, the reaction solvent M in a supercritical or subcritical state (pressurized gas or pressurized liquid) introduced through the inlet 16D moves in the first reaction section 16A in the first direction Y1. In the first reaction section 16A, the reaction solvent M in a supercritical or subcritical state (pressurized gas or pressurized liquid) comes into contact with the polyester solution P. The polyester in the polyester solution P is depolymerized (reduced in molecular weight) by the reaction solvent M, and the depolymerized polyester is extracted into the reaction solvent M in a supercritical or subcritical state (pressurized gas or pressurized liquid). Hereinafter, the polyester depolymerized in the first reaction section 16A will be referred to as a first depolymerized polyester P1, and the mixture of the first depolymerized polyester P1 and the reaction solvent M (the reaction solvent M from which the first depolymerized polyester P1 has been extracted) will be referred to as a first solvent M1. The first solvent M1 containing the first depolymerized polyester P1 proceeds in the first direction Y1 through the first reaction section 16A and is discharged to the first direction Y1 side of the first reaction section 16A.

[0048] The first depolymerized polyester P1 contains monomers D and E produced by depolymerizing the polyester in the polyester solution P, monomer D that was originally mixed in the polyester solution P, and oligomers produced by depolymerizing the polyester. The oligomers here refer to oligomers of carboxylic acid or alcohol components that have not been monomerized but have been depolymerized from the polyester (oligomers of carboxylic acid or alcohol components that have a smaller molecular weight than the polyester).

[0049] (Second reaction section) The second reaction section 16B is formed in the reaction section 16, and is formed at a location where the first solvent M1 is discharged from the first reaction section 16A. In this embodiment, since the first solvent M1 is discharged in the first direction Y1, the second reaction section 16B can be said to be a space formed on the first direction Y1 side of the first reaction section 16A.

[0050] In the second reaction section 16B, the first depolymerized polyester P1 contained in the first solvent M1 is further depolymerized (reduced in molecular weight) by the reaction solvent M contained in the first solvent M1. Hereinafter, the first depolymerized polyester P1 further depolymerized in the second reaction section 16B will be referred to as the second depolymerized polyester P2, and the mixture of the second depolymerized polyester P2 and the reaction solvent M (the reaction solvent M in which the second depolymerized polyester P2 is dissolved) will be referred to as the second solvent M2. An outlet pipe 16a is connected to the second reaction section 16B. More specifically, an outlet 16E, which is an opening of the outlet pipe 16a through which the second solvent M2 is discharged from the second reaction section 16B, is connected to the second reaction section 16B. The second solvent M2 containing the second depolymerized polyester P2 in the second reaction section 16B is discharged from the outlet 16E through the outlet pipe 16a to the outside of the second reaction section 16B.

[0051] The second depolymerized polyester P2 contains the monomers D and E in the first depolymerized polyester P1, the monomers D and E produced by depolymerizing the oligomers in the first depolymerized polyester P1, and the oligomers produced by depolymerizing the first depolymerized polyester P1.

[0052] A discharge pipe 16b is connected to the bottom of the reaction section 16. More specifically, a discharge port 16F, which is an opening of the discharge pipe 16b through which non-extractable materials (described below) in the reaction section 16 are discharged, is connected to the bottom of the reaction section 16. The non-extractable materials include impurities such as metal compounds that were not extracted into the reaction solvent M and residues of undecomposed polyester that were not extracted into the reaction solvent M. That is, the non-extractable materials at the bottom of the reaction section 16 are discharged from the discharge port 16F through the discharge pipe 16b to the outside of the reaction section 16. The non-extractable materials discharged from the discharge port 16F can be considered to be components of the polyester solution P that were not introduced into the separation section 18 as the second solvent M2 (the reaction solvent M in which the second depolymerized polyester P2 is dissolved) and remained in the first reaction section 16A and the second reaction section 16B.

[0053] The reaction section 16 may also be provided with a heating section that heats the interior of the reaction section 16 and a pressurizing section that maintains the pressure inside the reaction section 16 at a predetermined value or higher. The temperature inside the reaction section 16 is preferably 250°C or higher and 400°C or lower, and more preferably 250°C or higher and 350°C or lower. The pressure inside the reaction section 16 is preferably 1 MPa or higher and 30 MPa or lower, and more preferably 6 MPa or higher and 25 MPa or lower. The pressurizing section and the heating section may be controlled by the control section 30.

[0054] (separation part) The separation unit 18 receives the second solvent M2 containing the second depolymerized polyester P2 and separates the second solvent M2 into the reaction solvent M, the carboxylic acid-derived monomer D contained in the second depolymerized polyester P2, the alcohol component monomer E contained in the second depolymerized polyester P2, and residual substances. The residual substances are components of the second solvent M2 other than the reaction solvent M, the monomer D, and the monomer E, and include oligomers.

[0055] In this embodiment, the separation section 18 has a first separation section 18A, a second separation section 18B, and a third separation section 18C.

[0056] The first separation section 18A is a separation column connected to the outlet pipe 16a. A second solvent M2 containing a second depolymerized polyester P2 is introduced into the first separation section 18A via the outlet pipe 16a. The first separation section 18A separates the second solvent M2 into a low-boiling component and a high-boiling component having a higher boiling point than the low-boiling component. For example, in the first separation section 18A, the second solvent M2 may be heated to a predetermined temperature, and the gaseous component may be the low-boiling component and the liquid component may be the high-boiling component. The first separation section 18A is connected to outlet pipes 18Aa and 18Ab. The low-boiling component is discharged from the outlet pipe 18Aa, and the high-boiling component is discharged from the outlet pipe 18Ab.

[0057] The second separation section 18B is a separation column connected to the first separation section 18A via an outlet pipe 18Aa. Low-boiling point components are introduced into the second separation section 18B via the outlet pipe 18Aa. The second separation section 18B separates the low-boiling point components into reaction solvent M and monomer E. Outlet pipes 18Ba and 18Bb are connected to the second separation section 18B. The reaction solvent M is discharged from the outlet pipe 18Ba, and the monomer E is discharged from the outlet pipe 18Bb. The outlet pipe 18Ba is connected to the second separation section 18B and the reaction solvent reservoir 14. Therefore, the reaction solvent M discharged from the second separation section 18B is returned to the reaction solvent reservoir 14 and reused for depolymerization of polyester.

[0058] The third separation section 18C is a separation column connected to the first separation section 18A via the outlet pipe 18Ab. High-boiling components are introduced into the third separation section 18C via the outlet pipe 18Ab. The third separation section 18C further separates the high-boiling components into high-boiling residual substances, low-boiling components containing reaction solvent M and monomer E, and monomer D. The third separation section 18C is connected to the outlet pipes 18Ca, 18Cb, and 18Cc. The outlet pipe 18Ca is connected to the second separation section 18B. The low-boiling components separated in the third separation section 18C are discharged to the second separation section 18B via the outlet pipe 18Ca. The monomer D separated in the third separation section 18C is discharged from the outlet pipe 18Cb, and the residual substances separated in the third separation section 18C are discharged from the outlet pipe 18Cc.

[0059] An inlet pipe 18Cd is connected to the third separation section 18C. The inlet pipe 18Cd is also connected to the dissolving section 12 and introduces the monomer D discharged from the third separation section 18C into the dissolving section 12. In the example shown in FIG. 2, the inlet pipe 18Cd branches off from the outlet pipe 18Cb. The inlet pipe 18Cd is provided with an adjustment section 18Ce that adjusts the amount of monomer D supplied from the third separation section 18C to the dissolving section 12. The adjustment section 18Ce is, for example, an on-off valve that, when open, allows the monomer D to be supplied to the dissolving section 12 and, when closed, stops the supply of the monomer D to the dissolving section 12. However, the adjustment section 18Ce is not limited to an on-off valve and may be any mechanism capable of adjusting the supply of monomer D to the dissolving section 12. In this embodiment, the adjustment section 18Ce is provided at the point where the inlet pipe 18Cd branches off from the outlet pipe 18Cb, but the adjustment section 18Ce may be provided at any position. Furthermore, the inlet pipe 18Cd does not have to be connected to the outlet pipe 18Cb, and may be directly connected to the third separation section 18 C. Furthermore, for example, the outlet pipe 18Cb may be provided with a reservoir (tank) for storing the monomer D, and the inlet pipe 18Cd may be connected to the reservoir.

[0060] Note that the outlet pipe 18Cc may be connected to the dissolving section 12 to introduce at least a portion of the residual substances into the dissolving section 12. By introducing the residual substances into the dissolving section 12, it becomes possible to depolymerize the oligomers contained in the residual substances again in the reaction section 16, thereby improving the yield of monomers.

[0061] (Control unit) The control unit 30 is a control device that controls the separation system 1. The control unit 30 controls the adjustment unit 10b to control the amount of polyester raw material Pm supplied from the raw material storage unit 10 to the dissolution unit 12. The control unit 30 controls the foreign matter recovery unit 50 to recover impurities captured in the solid-liquid separation unit 13. Furthermore, if the solid-liquid separation unit 13 is equipped with a drive unit, the control unit 30 controls the operation of the solid-liquid separation unit 13. The control unit 30 controls the adjustment unit 12a1 to control the amount of dissolution liquid Pd supplied from the dissolution unit 12 to the storage unit 20. The control unit 30 controls the discharge unit 22 to discharge, from the storage unit 20, the impurities R separated from the polyester solution P in the storage unit 20. The control unit 30 controls the discharge unit 24 to discharge, from the storage unit 20, the polyester solution P separated from the impurities R in the storage unit 20, and to control the amount of polyester solution P introduced into the reaction unit 16. The control unit 30 controls the heating and pressurizing unit 14b to bring the reaction solvent M into a supercritical state or a subcritical state (pressurized gas or pressurized liquid), and controls the amount of the reaction solvent M in the supercritical state or subcritical state (pressurized gas or pressurized liquid) supplied to the reaction unit 16. The control unit 30 controls the adjustment unit 18Ce to control the amount of the monomer D supplied to the dissolution unit 12.

[0062] In this embodiment, the control unit 30 is a computer, and includes a processor including an arithmetic circuit such as a CPU (Central Processing Unit), and a storage unit that stores various information such as the contents of calculations performed by the processor and programs. The control unit 30 executes control of the separation system 1 by reading out the programs from the storage unit.

[0063] However, the separation system 1 is not limited to being automatically controlled by the control unit 30, and for example, at least a part of the processing may be controlled by the operation of an operator.

[0064] (Separate system operation) Next, the operation of the separation system 1 will be described. The control unit 30 controls the adjustment units 10b and 18Ce to introduce the polyester raw material Pm and the monomer D into the dissolution unit 12, and mix the polyester raw material Pm and the monomer D in the dissolution unit 12 to generate a solution Pd. The control unit 30 controls the adjustment unit 12a1 to introduce the solution Pd generated in the dissolution unit 12 into the storage unit 20. The separation system 1 removes impurities R from the solution Pd supplied from the dissolution unit 12 to the storage unit 20 in the solid-liquid separation unit 13. The solution Pd introduced into the storage unit 20 is allowed to stand for a predetermined time, whereby it is separated by gravity into a layer of first impurities R1, a layer of polyester solution P, and a layer of second impurities R2. Note that the method for allowing the solution Pd to stand may be arbitrary.

[0065] The control unit 30 controls the discharge unit 22 to discharge the first impurity R1 and the second impurity R2 from the storage unit 20, while controlling the discharge unit 24 to discharge the polyester solution P from the storage unit 20. The polyester solution P discharged from the storage unit 20 has the third impurity R3 removed by the removal unit 26, and is then introduced into the first reaction unit 16A. The control unit 30 controls the heating and pressurization unit 14b to supply the reaction solvent M in a supercritical or subcritical state (pressurized gas or pressurized liquid) to the reaction unit 16. The control unit 30 preferably controls the reaction solvent M to a temperature of 250°C or higher and 400°C or lower, and more preferably controls the reaction solvent M to a temperature of 250°C or higher and 350°C or lower. The control unit 30 preferably controls the reaction solvent M to a pressure of 1 MPa or higher and 30 MPa or lower, and more preferably controls the reaction solvent M to a pressure of 6 MPa or higher and 25 MPa or lower.

[0066] In this manner, by supplying the polyester solution P and the reaction solvent M to the reaction section 16, the polyester contained in the polyester solution P is depolymerized in the first reaction section 16A to produce a first depolymerized polyester P1. Then, in the second reaction section 16B, the first depolymerized polyester P1 is further depolymerized to produce a second solvent M2, which is a mixture of the second depolymerized polyester P2 and the reaction solvent M. The second solvent M2 is separated into the reaction solvent M, monomer D, monomer E, and residual substances in the first separation section 18A, second separation section 18B, and third separation section 18C. As a result, the monomers D and E are recovered from the polyester raw material Pm, and by polymerizing them, polyester can be regenerated.

[0067] (Filter configuration) Next, the configuration of the filter 26a will be described using a dead-end filtration method. In this embodiment, the filter 26a is not limited to a dead-end filtration method, and may be, for example, a cross-flow method. In this embodiment, the filter 26a is arranged vertically, but may be arranged horizontally. In this case, the polyester solution P flows horizontally through the filter 26a. FIG. 3 is a schematic diagram showing the configuration of the filter. FIG. 4 is a schematic top view of the filter. The filter 26a includes a storage container 40 and a filter 47.

[0068] (storage container) The storage container 40 is a container that stores a filter 47. The storage container 40 has a lid portion 41, a storage portion 43, and a partition member 45.

[0069] The storage section 43 is a container having a bottom and side surfaces and an open top surface, and stores the filter 47. A flange portion 43a is formed at the top end of the storage section 43. An opening 43b through which a fluid passes is formed in the bottom surface of the storage section 43, which is the surface on the upper side in the Y direction. The top end of the storage section 43 does not have to be flange-shaped. For example, the flange portion 43a may have any shape that can fix the lid portion 41 to the storage section 43.

[0070] The lid portion 41 closes the top surface of the storage portion 43. The lid portion 41 is fixed to the storage portion 43. An inlet pipe 20c1 for supplying the polyester solution P is connected to the lid portion 41. The lid portion 41 supplies the supplied polyester solution P to the storage portion 43. A flange portion 41a is formed at the upper end of the lid portion 41. A flange portion 41b is formed at the lower end of the lid portion 41.

[0071] (Partition material) The partition member 45 is disposed in the storage section 43. The partition member 45 supports a plurality of filters 47 disposed in the storage section 43. The partition member 45 is fixed to the lid section 41 side of the storage section 43. The partition member 45 is a structure that does not allow liquid to pass through except for the connection section with the filters 47. The partition member 45 separates the space surrounded by the storage section 43 and the lid section 41 into a first space 42 on the lid section 41 side and a second space 44 on the bottom side of the storage section 43.

[0072] (filter) The filter 47 is a cylindrical member extending in the Y direction (vertical direction) and is disposed inside the storage container 40. The storage container 40 has a plurality of filters 47 disposed in parallel. In this embodiment, the filter 47 is a ceramic filter made of porous ceramic. The polyester solution P from the first space 42 flows into the filter 47, passes through the side and bottom surfaces, and is discharged into the second space 44. Impurities are filtered out of the polyester solution P as it passes through the filter 47. As the polyester solution P flows through the filter 47, components contained in the polyester solution P adhere to the filter 47. Specifically, some polyesters contained in the polyester solution P and third impurities R3 adhere to the filter 47. The filter 47 collects the third impurities R3 contained in the polyester solution P. Specifically, the filter 47 collects impurities contained in the third impurities R3, such as polymerization catalysts and solid inorganic substances, which are large in diameter. As a result, some of the impurities contained in the third impurity R3 are collected, and the polyester solution P after the impurities have been collected is introduced into the adsorption tower.

[0073] The number and arrangement of the filters 47 are not limited to the example in FIG. 4 and may be arbitrary. The number and arrangement of the circulation holes 47a are not limited to the example in FIG. 4 and may be arbitrary. The structure of the filter 47 is not limited to a porous structure and may be any structure such as a mesh structure or a mesh shape. The filter 47 is not limited to a ceramic filter.

[0074] The housing 48 is detachably disposed inside the storage section 43 and supports the filter 47. The housing 48 may be connected to the partition member 45. The housing 48 only needs to be able to fix the filter 47 to the storage section 43, and has a structure that allows the polyester solution P in the storage section 43 to pass through, for example, a structure that has an opening.

[0075] The polyester solution P flowing through the filter 26a is discharged to the outside via a filter 47 housed in the storage container 40. Specifically, the polyester solution P flowing through the filter 26a passes through the first space 42 of the lid 41, flows toward the opening 43b formed in the storage section 43, and is discharged to the adsorption tower 26b.

[0076] (Cleaning equipment) FIG. 5 is a schematic diagram of a cleaning device according to the first embodiment. The cleaning device 100 cleans the filter 26a. The cleaning device 100 includes a storage container 60, a supply unit 70, and a control unit 80. The cleaning device 100 stores a filter 47 in the storage container 60, and supplies cleaning liquid C for cleaning the filter from the supply unit 70 to clean the filter 47 in the storage container 60. In the example shown in FIG. 5, the cleaning device 100 is configured so that the cleaning liquid C flows vertically within the storage container 60, but the cleaning liquid C may also flow horizontally. In this case, it is preferable to store the filter 47 horizontally. Note that the structure, installation orientation, and flow direction of the cleaning liquid C of the filter 47 are not particularly limited as long as the filter 47 can filter the cleaning liquid C.

[0077] (storage container) The storage container 60 is a container that stores the filter 47. The filter 47 to be cleaned has been used in the filtering device 26a and has solidified polyester and impurities attached to it. The storage container 60 stores the filter 47 along the Y direction. The storage container 60 stores multiple filters 47. The storage container 60 may store the filter 47 together with the housing 48 in which the filter 47 is stored. Alternatively, the storage container 60 may store only one filter 47. The storage container 60 has a lid portion 61, a storage portion 63, and a partition member 65. The storage container 60 is connected to an outlet pipe 67 and a supply portion 70.

[0078] The storage unit 63 is a container having a bottom and sides, and stores the filter 47 to be cleaned. A supply unit 70 that supplies cleaning liquid for cleaning the filter 47 is connected to the storage unit 63 via a supply pipe 77. The storage unit 63 is also connected to an outlet pipe 67 through which cleaning liquid AC flows after cleaning the filter 47. A differential pressure gauge 66 is connected to the storage unit 63. A flange portion 63a is formed at the upper end of the storage unit 63.

[0079] The lid 61 is a structure that closes the top surface of the storage section 63, and is fixed in a state that allows it to open and close the top surface of the storage section 63. The lid 61 has a flange 61b formed at its lower end.

[0080] The partition member 65 is placed in the storage section 63. The partition member 65 supports the filter 47 to be cleaned that is placed in the storage section 63. The partition member 65 is fixed to the lid section 61 side of the storage section 63. The partition member 65 is a structure that does not allow liquid to pass through except for the connection section with the filter 47. The partition member 65 separates the space surrounded by the storage section 63 and the lid section 61 into a first space 62 on the lid section 61 side and a second space 64 on the bottom side of the storage section 63.

[0081] The differential pressure gauge 66 measures the differential pressure of the filter 47. One end of the differential pressure gauge 66 is connected to the first space 62, and the other end is connected to the second space 64. The differential pressure gauge 66 measures the differential pressure while the filter 47 is being cleaned. The differential pressure gauge 66 measures the difference in pressure upstream and downstream of the filter 47, specifically the difference in pressure between the first space 62 and the second space 64. When the opening of the filter 47 is blocked, a pressure loss occurs. For this reason, the pressure difference measured by the differential pressure gauge 66 indicates a larger value than when the opening of the filter 47 is not blocked. Therefore, the pressure difference measured by the differential pressure gauge 66 decreases as the filter 47 is cleaned, and therefore decreases from the start of cleaning the filter 47 toward the end of cleaning.

[0082] The outlet pipe 67 is connected to the storage container 60. The outlet pipe 67 is connected to the first space of the storage container 60. The outlet pipe 67 is through which the cleaning liquid AC flows after cleaning the filter 47. The outlet pipe 67 discharges the fluid from which substances adhering to the filter 47 have been removed, from the storage container 60 to the outside.

[0083] (Supply Department) The supply unit 70 is connected to the storage container 60 via a supply pipe 77. One end of the supply pipe 77 is connected to each of the first fluid supply unit 71, the second fluid supply unit 72, and the third fluid supply unit 73, and the other end is connected to the second space of the storage container 60. One end of the supply pipe 77 branches into a branch pipe, and the other end is a main pipe. Each branch pipe of the supply pipe 77 is connected to the first fluid supply unit 71, the second fluid supply unit 72, and the third fluid supply unit 73. The main pipe of the supply pipe 77 is connected to the storage container 60. The supply pipe 77 may connect each part of the supply unit 70 to the storage container 60 via separate pipes. The pump 78 is provided in the supply pipe 77. The pump 78 is provided at a position (main pipe) of the supply pipe 77 where the supply pipe 77 does not branch. The pump 78 sends the cleaning liquid C flowing through the supply pipe 77 to the storage container 60.

[0084] The supply unit 70 includes a first fluid supply unit 71, a second fluid supply unit 72, and a third fluid supply unit 73. The supply unit 70 supplies the first fluid C1, the second fluid C2, and the third fluid C3 from the first fluid supply unit 71, the second fluid supply unit 72, and the third fluid supply unit 73, respectively, to the storage container 60 in that order via a supply pipe 77. Hereinafter, when there is no need to distinguish between the first fluid C1, the second fluid C2, and the third fluid C3, they will be referred to as cleaning liquid C as appropriate.

[0085] The first fluid C1 is a liquid that removes solidified polyester from the filter 47. The first fluid C1 is a liquid that dissolves polyester. In this embodiment, the first fluid C1 is a cleaning liquid containing triethylene glycol as a main component. Note that the first fluid C1 may be any liquid as long as it can remove solidified polyester.

[0086] The second fluid C2 is an acidic or alkaline liquid. The second fluid C2 is a cleaning liquid that removes impurities adhering to the filter 47 after the first fluid C1 has removed the solidified polyester from the filter 47. The second fluid C2 removes impurities by washing them away or dissolving them. Whether the second fluid C2 is an acidic liquid or an alkaline liquid is determined depending on the equipment in which the filter 47 is used.

[0087] The third fluid C3 is used after the second fluid C2 removes impurities adhering to the filter 47. The third fluid C3 is a cleaning liquid that cleans the filter 47 after the impurities have been removed from the filter 47. In this embodiment, the third fluid C3 is ion-exchanged water.

[0088] The first fluid supply unit 71 includes a first fluid supply tank 71a and a first fluid adjustment unit 71b. The first fluid supply tank 71a is connected to the storage container 60 via a supply pipe 77. The first fluid supply tank 71a stores the first fluid C1. The first fluid adjustment unit 71b is provided on the supply pipe 77. The first fluid adjustment unit 71b is a valve that controls the flow rate of the first fluid C1. The first fluid adjustment unit 71b is, for example, an on-off valve that opens when the first fluid C1 is to be supplied, allowing the first fluid C1 in the first fluid supply tank 71a to be supplied to the storage container 60. When the first fluid C1 is not to be supplied, the first fluid adjustment unit 71b closes, stopping the supply of the first fluid C1 in the first fluid supply tank 71a to the storage container 60. However, the first fluid adjustment unit 71b is not limited to being an on-off valve and may be any mechanism that can adjust the supply of the first fluid C1 to the storage container 60. The first fluid supply unit 71 supplies the first fluid C1 to the storage container 60. The first fluid supply unit 71 supplies the first fluid C1 to the storage container 60 to backwash the filter 47 stored in the storage container 60. The first fluid supply unit 71 supplies the first fluid C1 to the storage container 60, and removes solidified polyester adhering to the filter 47 stored in the storage container 60 by the first fluid C1.

[0089] The second fluid supply unit 72 includes a second fluid supply tank 72a and a second fluid adjustment unit 72b. The second fluid supply tank 72a is connected to the storage container 60 via a supply pipe 77. The second fluid supply tank 72a stores the second fluid C2. The second fluid adjustment unit 72b is provided on the supply pipe 77. The second fluid adjustment unit 72b is a valve that adjusts the flow rate of the second fluid C2. The second fluid adjustment unit 72b is, for example, an on-off valve that opens when the second fluid C2 is to be supplied, allowing the second fluid C2 in the second fluid supply tank 72a to be supplied to the storage container 60. When the second fluid C2 is not to be supplied, the second fluid adjustment unit 72b closes, stopping the supply of the second fluid C2 in the second fluid supply tank 72a to the storage container 60. However, the second fluid adjustment unit 72b is not limited to being an on-off valve and may be any mechanism that can adjust the supply of the second fluid C2 to the storage container 60. The second fluid supply unit 72 supplies the second fluid C2 to the storage container 60 after the first fluid supply unit 71 supplies the first fluid C1 to the storage container 60. The second fluid supply unit 72 supplies the second fluid C2 to the storage container 60 to backwash the filter 47 stored in the storage container 60. The second fluid supply unit 72 supplies the second fluid C2 to the storage container 60, and removes impurities adhering to the filter 47 stored in the storage container 60 by the second fluid C2.

[0090] The third fluid supply unit 73 includes a third fluid supply tank 73a and a third fluid adjustment unit 73b. The third fluid supply tank 73a is connected to the storage container 60 via a supply pipe 77. The third fluid supply tank 73a stores the third fluid C3. The third fluid adjustment unit 73b is provided on the supply pipe 77. The third fluid adjustment unit 73b is a valve that adjusts the flow rate of the third fluid C3. The third fluid adjustment unit 73b is, for example, an on-off valve that opens when the third fluid C3 is to be supplied, allowing the third fluid C3 in the third fluid supply tank 73a to be supplied to the storage container 60. When the third fluid C3 is not to be supplied, the third fluid adjustment unit 73b closes, stopping the supply of the third fluid C3 in the third fluid supply tank 73a to the storage container 60. However, the third fluid adjustment unit 73b is not limited to being an on-off valve and may be any mechanism that can adjust the supply of the third fluid C3 to the storage container 60. The third fluid supply unit 73 supplies the third fluid C3 to the storage container 60 after the second fluid supply unit 72 supplies the second fluid C2 to the storage container 60. The third fluid supply unit 73 supplies the third fluid C3 to the storage container 60 and backwashes the filter 47 stored in the storage container 60 with the third fluid C3. The third fluid supply unit 73 supplies the third fluid C3 to the storage container to remove the second fluid C2 adhering to the filter 47.

[0091] (Control unit) The control unit 80 is a control device that controls the cleaning apparatus 100. The control unit 80 controls the first fluid adjustment unit 71b to control the amount of the first fluid C1 supplied from the first fluid supply tank 71a to the storage container 60. The control unit 80 controls the second fluid adjustment unit 72b to control the amount of the second fluid C2 supplied from the second fluid supply tank 72a to the storage container 60. The control unit 80 controls the third fluid adjustment unit 73b to control the amount of the third fluid C3 supplied from the third fluid supply tank 73a to the storage container 60. For example, the control unit 80 acquires a value indicated by the differential pressure gauge 66 and controls the flow rate of the cleaning liquid C.

[0092] In this embodiment, the control unit 80 is a computer, and includes a processor including an arithmetic circuit such as a CPU, and a storage unit that stores various information such as the contents of calculations performed by the processor and programs. The control unit 80 controls the cleaning apparatus 100 by reading out the programs from the storage unit.

[0093] However, the cleaning device 100 is not limited to being automatically controlled by the control unit 80, and for example, at least a part of the processing may be controlled by an operator's operation.

[0094] (backwashing) Next, backwashing will be described. In this embodiment, the supply unit 70 supplies the cleaning liquid C to the outer peripheral surface side (second space 64) of the filter 47 housed in the storage container 60. The supply unit 70 causes the cleaning liquid C supplied to the storage container 60 to flow into the filter 47. The supply unit 70 backwashes the filter 47 by causing the cleaning liquid C to flow within the storage container 60 from the bottom surface (the surface on the Y2 direction side) of the filter 47 to the top surface (the surface on the Y1 direction side). The cleaning liquid C that has flowed from the bottom surface to the top surface of the filter 47 flows in the Y1 direction (first space 62) beyond the partition member 65 due to the pressure difference between the first space 62 and the second space 64, and is discharged from the discharge pipe 67 as cleaning liquid AC after cleaning the filter 47.

[0095] Fig. 6 is a diagram illustrating the control of the cleaning device according to the first embodiment. The horizontal axis of Fig. 6 represents time, and the vertical axis represents differential pressure. Line L represents the change in differential pressure of filter 47. That is, on line L, the differential pressure of filter 47 decreases as backwashing begins. In other words, when solidified polyester and impurities adhering to filter 47 are removed (clogging is eliminated), the differential pressure decreases.

[0096] A predetermined differential pressure is set in advance in the control unit 80 for each cleaning liquid C. For example, in FIG. 6, the predetermined differential pressure of the first fluid C1 is differential pressure P1, and the differential pressure of the second fluid C2 is differential pressure P2. Ranges may be set for the differential pressure P1 and differential pressure P2. In this embodiment, the range of the differential pressure P1 is 0.10 MPa to 0.15 MPa, and the range of the differential pressure P2 is 0.05 MPa to 0.08 MPa. The ranges of the differential pressure P1 and differential pressure P2 are not limited to the above ranges and may be set arbitrarily.

[0097] The control unit 80 controls the first fluid supply unit 71 during a first period t1, from time T0 to a first timing T1, so that the first fluid supply unit 71 supplies the first fluid C1 to the storage container 60. The first timing T1 is the time when the differential pressure of the filter 47, as indicated by the differential pressure gauge 66, reaches a differential pressure P1. The control unit 80 also controls the first fluid supply unit 71 during a second period t2, from the first timing T1 to a second timing T2, so that the first fluid supply unit 71 supplies the first fluid C1 to the storage container 60. The second period t2 is the retention time during which the first fluid C1 remains in the storage container 60. In other words, the backwashing of the filter 47 with the first fluid C1 occurs from time T0 to the second timing T2. By providing a retention time, solidified polyester adhering to the filter 47 is more effectively removed.

[0098] The control unit 80 switches the fluid supplied to the storage container 60 from the first fluid C1 to the second fluid C2 and controls the second fluid supply unit 72 to supply the second fluid C2 to the storage container 60 during a third period t3 from the second timing T2 to the third timing T3. The third period T3 is the time when the differential pressure of the filter 47 indicated by the differential pressure gauge 66 becomes the differential pressure P2. The control unit 80 also controls the second fluid supply unit 72 to supply the second fluid C2 to the storage container 60 during a fourth period t4 from the third timing T3 to the fourth timing T4. The fourth period t4 is the time during which the second fluid C2 remains in the storage container 60. In other words, the backwashing of the filter 47 with the second fluid C2 occurs from the second timing T2 to the fourth timing T4. By providing a residence time, impurities adhering to the filter 47 (collected by the filter 47) are more effectively removed.

[0099] The control unit 80 controls the third fluid supply unit 73 during a fifth period t5 from the fourth timing T4 to the fifth timing T5, and the third fluid supply unit 73 supplies the third fluid C3 until the storage container 60 is filled with the third fluid C3. Once the storage container 60 is filled with the third fluid C3, the control unit 80 does not supply the third fluid C3 during a fifth period t5 from the fourth timing T4 to the fifth timing T5. The fifth period t5 is the retention time during which the third fluid C3 remains in the storage container 60. By providing this retention time, the filter 47 can be properly cleaned.

[0100] In this embodiment, the residence time of the first fluid C1, the second fluid C2, and the third fluid C3 in the storage container 60 is n times the time to fill the capacity of the storage container 60. More specifically, when the cleaning liquid C is supplied to the storage container 60 and the capacity of the storage container 60 (second space 64) is filled in X hours, the residence time of the cleaning liquid C is nX hours. In this embodiment, the residence time of the first fluid C1, the second fluid C2, and the third fluid C3 in the storage container 60 is preferably three times the time to fill the capacity, i.e., 3X hours. Note that the residence time may be determined arbitrarily.

[0101] (effect) Over time, the filter openings of the filter become clogged (blocked) due to the adhesion of polyester and impurities contained in the polyester solution P flowing through the filter. When the filter openings become clogged, the impurity collection performance decreases. As a result, impurities that would have been captured by the filter of the filter are led to the adsorption tower and captured by the adsorbent in the adsorption tower. Filters with reduced impurity collection performance are disposed of and replaced with new ones, or the filter is washed to remove the impurities. However, due to the increased cost of filter replacement and the drop in filter temperature during washing, the polyester adhering to the filter solidifies, making it impossible to remove the impurities. Furthermore, when the collection performance of the filter of the filter decreases, impurities are captured by the adsorbent in the adsorption tower, increasing the amount of adsorbent required.

[0102] In contrast, the cleaning device 100 includes a storage container 60, a first fluid supply unit 71, and a second fluid supply unit 72. The first fluid supply unit 71 supplies a first fluid C1 to the storage container 60, and the second fluid supply unit 72 supplies a second fluid C2 to the storage container 60. When the filter 47 is stored in the storage container 60 from the filter 26a, polyester adhering to the filter 47 solidifies. In this embodiment, the first fluid C1 and the second fluid C2 are separate liquids. Therefore, by supplying the first fluid C1 to the storage container 60 by the first fluid supply unit 71, the solidified polyester on the filter 47 stored in the storage container 60 can be removed. Furthermore, after the first fluid supply unit 71 supplies the first fluid C1 to the storage container 60, the second fluid supply unit 72 supplies the second fluid C2 to the storage container 60, so that impurities adhering to the filter 47 can also be removed. Therefore, foreign matter can be stably removed. Furthermore, by collecting impurities (polymerization catalyst) with large particle sizes using the filter 26a, the amount of polymerization catalyst and solid inorganic matter adsorbed by the adsorbent in the adsorption tower 26b can be reduced, thereby extending the service life of the adsorbent, and thus reducing the required amount of adsorbent in the adsorption tower 26b.

[0103] (Second embodiment) Next, a second embodiment will be described. The second embodiment differs from the first embodiment in that the separation system 1A includes (has incorporated therein) a cleaning device 100A. Specifically, the second embodiment differs from the first embodiment in that the storage container 60 of the cleaning device 100 is integrated with the storage container 40 of the separation system 1A. In the second embodiment, explanations of parts that are common to the first embodiment will be omitted.

[0104] Fig. 7 is a partial schematic diagram of a separation system according to the second embodiment. As shown in Fig. 7, a separation system 1A according to the second embodiment includes a cleaning device 100A.

[0105] In the separation system 1A, a cleaning device 100A is connected to a storage container 40 of the filter 26aA. Specifically, in the separation system 1A, an outlet pipe 67 is connected to an inlet pipe 20c1 connected to the filter 26aA. In the separation system 1A, a supply unit 70 is connected to an inlet pipe 20c2 connected to the filter 26aA. The supply unit 70 is the same as in the first embodiment, and therefore a description thereof will be omitted.

[0106] The structure and function of filter 26aA are similar to those of filter 26a, and therefore will not be described. In filter 26aA, inlet pipe 20c2 branches off, and supply pipe 77 is connected to inlet pipe 20c2. In addition, in filter 26A, inlet pipe 20c1 branches off, and outlet pipe 67 is connected. That is, inlet pipe 20c2 is joined with supply pipe 77, and inlet pipe 20c1 is joined with outlet pipe 67.

[0107] The inlet pipe 20c1 is provided with an adjustment unit 90. The adjustment unit 90 is a valve that allows the polyester solution P to flow. The adjustment unit 90 is, for example, an on-off valve that is open when the polyester solution P flows through the inlet pipe 20c1 and supplies the polyester solution P from the storage unit 20 to the storage container 40, and is closed when the filter 26a is being cleaned and stops the supply of the polyester solution P from the storage unit 20 to the storage container 40. However, the adjustment unit 90 is not limited to being an on-off valve and may be any mechanism that can supply the polyester solution P to the storage container 40.

[0108] The inlet pipe 20c2 is provided with an adjustment unit 92. Similar to the adjustment unit 90, the adjustment unit 92 is in an open state when the polyester solution P flows through the inlet pipe 20c2, allowing the polyester solution P flowing through the filter 26a to be supplied to the adsorption tower 26b, and is in a closed state when the filter 26a is being washed, stopping the supply of the polyester solution P flowing through the filter 26a to the adsorption tower 26b. However, the adjustment unit 92 is not limited to being an on-off valve, and may be any mechanism capable of supplying the polyester solution P to the adsorption tower 26b.

[0109] The outlet pipe 67 is provided with an adjustment unit 94. The adjustment unit 94 is a valve that discharges the cleaning liquid AC after cleaning the filter 47. The adjustment unit 94 is, for example, an on-off valve that opens when the filter 26aA is being cleaned, allowing the cleaning liquid AC from the filter 26aA to be discharged to the outside, and closes when the filter 26aA is not being cleaned, preventing the polyester solution P from being discharged to the outside. The adjustment unit 94 is not limited to being an on-off valve, and may be any mechanism that allows the cleaning liquid AC from the filter 26aA to be discharged to the outside and prevents the polyester solution P from being discharged to the outside.

[0110] The differential pressure gauge 66A measures the differential pressure of the filter 47. One end of the differential pressure gauge 66A is connected to the first space 42, and the other end is connected to the second space 44. The differential pressure gauge 66A measures the differential pressure while the filter 47 is being cleaned. The differential pressure gauge 66A measures the difference in pressure upstream and downstream of the filter 47, specifically the difference in pressure between the first space 62 and the second space 64. When the opening of the filter 47 is blocked, a pressure loss occurs. For this reason, the pressure difference measured by the differential pressure gauge 66 indicates a larger value than when the opening of the filter 47 is not blocked. Therefore, the pressure difference measured by the differential pressure gauge 66 decreases as the filter 47 is cleaned, and therefore decreases from the start of cleaning the filter 47 toward the end of cleaning.

[0111] The filter 26aA is supplied with the polyester solution P from the reservoir 20, and the polyester solution P flows into the filter 47 housed in the storage container 40 and into the second space 44. Impurities from the polyester solution P that has passed through the filter 26aA are captured by the filter 47, and the polyester solution P is introduced into the adsorption tower 26b. When backwashing the filter 47, the filter 26aA is supplied with a cleaning liquid C from the supply unit 70, and the cleaning liquid C flows into the filter 47 housed in the storage container 40 and into the second space 44. The cleaning liquid C passes through the filter 47 from the outer peripheral surface of the filter 47 and flows in the Y1 direction. After cleaning the filter 47, the cleaning liquid AC is discharged to the outside through the discharge pipe 67.

[0112] The control unit 30A controls the adjusting units 90, 92, and 94. The control unit 30A controls the opening and closing of the adjusting units 90, 92, and 94 depending on whether the polyester solution P is flowing or the cleaning liquid C is flowing. This allows the supply unit 70 to flow the cleaning liquid C in the appropriate direction when cleaning the filter 47. That is, for example, the cleaning liquid C can be prevented from flowing through the inlet pipe 20c2 and being introduced into 26b. Furthermore, for example, when the polyester solution P flows through 20c1, the polyester solution P can be prevented from flowing into the outlet pipe 67.

[0113] Furthermore, the control unit 30A may acquire the value indicated by the differential pressure gauge 66A and notify a management terminal (not shown) of the timing to clean the filter 47. When it is time to clean the filter 47, the control unit 30A may automatically switch the operation mode to a cleaning mode and control the open / close state of the adjustment unit (on-off valve) to clean the filter 47. The control unit 30A may be provided with a display unit and display the timing to clean the filter on the display unit, or may notify a mobile terminal of an operator. The switching of the operation mode by the control unit 30A may also be performed by an operator.

[0114] (effect) In the second embodiment, the separation system includes a cleaning device. In the second embodiment, the first fluid C1 and the second fluid C2 are separate liquids, and the first fluid supply unit 71 supplies the first fluid C1 to the storage container 60, thereby removing solidified polyester from the filter 47 stored in the storage container 60. After the first fluid supply unit 71 supplies the first fluid C1 to the storage container 60, the second fluid supply unit 72 supplies the second fluid C2 to the storage container 60. This also removes impurities adhering to the filter 47. Therefore, foreign matter can be stably removed.

[0115] In the second embodiment, a differential pressure gauge is provided in the filter. Therefore, the control unit can acquire the value indicated by the differential pressure gauge and notify the timing of cleaning the filter. Therefore, the operator can know the timing of cleaning the filter in advance.

[0116] In the second embodiment, the washing device 100A may be provided before the adsorption tower 26b of the separation system 1A. For example, the washing device 100A may be provided between the reservoir 20 of the separation system 1A and the adsorption tower 26b.

[0117] (Other examples) Next, another example will be described. The other example differs from the first embodiment in that a heating unit 102 is connected to the storage container 60. In the other example, the description of parts that are common to the first embodiment will be omitted.

[0118] 8 is a schematic diagram of a cleaning apparatus according to another example. As shown in FIG. 8, a cleaning apparatus 100B according to another example includes a storage container 60B, a supply unit 70B, a control unit 80, and a heating unit 102.

[0119] The storage container 60B is a container that stores the filter 47. The filter 47 to be cleaned has been used in the filtering device 26a and has solidified polyester and impurities attached to it. The storage container 60B stores the filter 47 along the Y direction. The storage container 60B stores multiple filters 47. The storage container 60B may store the filter 47 together with the housing 48 in which the filter 47 is stored. Alternatively, the storage container 60B may store only one filter 47. The storage container 60B has a lid 61, a storage section 63, and a partition member 65. The storage container 60B is connected to an outlet pipe 67 and a supply section 70B. The storage container 60B is connected to a heating section 102.

[0120] The heating unit 102 is connected to the storage container 60B. The heating unit 102 heats the inside of the storage container 60B, thereby heating the filter 47 stored in the storage container 60B to a predetermined temperature. The predetermined temperature is a temperature at which the solidified polyester adhering to the filter 47 can be dissolved. By heating at the predetermined temperature in this manner, the solidified polyester can be dissolved. The predetermined temperature is preferably 140°C or higher and 300°C or lower, more preferably 160°C or higher and 280°C or lower, and even more preferably 190°C or higher and 250°C or lower.

[0121] The supply unit 70B includes a first fluid supply unit 71B, a second fluid supply unit 72, and a third fluid supply unit 73. The second fluid supply unit and the third fluid supply unit are similar to those in the first embodiment, and therefore description thereof will be omitted.

[0122] The first fluid supply unit 71B includes a first fluid supply tank 71aB and a first fluid adjustment unit 71bB. The first fluid supply tank 71aB is connected to the storage container 60B via a supply pipe 77. The first fluid supply tank 71aB stores the first fluid C1. The first fluid adjustment unit 71bB is provided on the supply pipe 77. The first fluid adjustment unit 71bB is a valve that controls the flow rate of the first fluid C1. The first fluid adjustment unit 71bB is, for example, an on-off valve that opens when the first fluid C1 is to be supplied, allowing the first fluid C1 in the first fluid supply tank 71aB to be supplied to the storage container 60B, and closes when the first fluid C1 is not to be supplied, stopping the supply of the first fluid C1 in the first fluid supply tank 71aB to the storage container 60B. However, the first fluid adjustment unit 71bB is not limited to being an on-off valve, and may be any mechanism capable of adjusting the supply of the first fluid C1 to the storage container 60B. The first fluid supply unit 71B supplies the first fluid C1 to the storage container 60B. The first fluid supply unit 71B supplies the first fluid C1 to the storage container 60B to backwash the filter 47 stored in the storage container 60B. The first fluid supply unit 71B supplies the first fluid C1 to the storage container 60B, and uses the first fluid C1 to remove solidified polyester adhering to the filter 47 stored in the storage container 60B.

[0123] (Modification of other examples) Next, a modification of another example will be described. In a cleaning device 100C according to a modification of another example, a heating unit 102 is connected to a first fluid supply unit 71C.

[0124] In another example, the heating unit 102 is provided in the storage container 60B, but is not limited thereto and may be provided in the supply unit 70C. FIG. 9 is a schematic diagram of a cleaning device according to a modified example of another example. In this case, as shown in FIG. 9, the heating unit 102 is provided in the first fluid supply unit 71C. Specifically, the heating unit 102 is provided in the first fluid supply tank 71aC and heats the first fluid C1 in the first fluid supply tank 71aC to a predetermined temperature by heating the inside of the first fluid supply tank 71aC. The predetermined temperature is a temperature at which the solidified polyester adhering to the filter 47 can be dissolved. The first fluid adjustment unit 71bC supplies the first fluid C1 heated by the heating unit 102 to the storage container 60. By heating the first fluid C1 to the predetermined temperature in this manner, the solidified polyester adhering to the filter can be dissolved.

[0125] (effect) In another example, the cleaning device is provided with a heating section, in which case the solidified polyester adhering to the filter can be heated and dissolved to remove the solidified polyester from the filter.

[0126] In another example, the first fluid C1 is a liquid that does not contain triethylene glycol as a main component.

[0127] (Effects of the present disclosure) The cleaning device according to the first aspect of the present disclosure includes a storage container 60 for storing a filter 47 having solidified polyester and impurities attached thereto, a first fluid supply unit 71 for supplying a first fluid C1 to the storage container 60 to remove the solidified polyester from the filter 47, and a second fluid supply unit 72 for supplying a second fluid C2 to the storage container 60 to remove the impurities from the filter 47 after the first fluid supply unit 71 has supplied the first fluid C1 to the storage container 60.

[0128] According to the present disclosure, the first fluid supply unit supplies the first fluid to the container, thereby removing solidified polyester from the filter. After the first fluid supply unit supplies the first fluid to the container, the second fluid supply unit supplies the second fluid to the container. This also removes impurities adhering to the filter. Therefore, foreign matter can be stably removed.

[0129] A cleaning device according to a second aspect of the present disclosure is the cleaning device according to the first aspect, in which the first fluid supply unit 71 backwashes the filter 47 with a first fluid C1 in the storage container 60, and the second fluid supply unit 72 backwashes the filter 47 with a second fluid C2 in the storage container 60. This makes it possible to remove solidified polyester and impurities adhering to the filter.

[0130] A cleaning device according to a third aspect of the present disclosure is the cleaning device according to the first or second aspect, wherein the first fluid C1 is a liquid that dissolves polyester, thereby making it possible to remove solidified polyester adhering to the filter.

[0131] A cleaning device according to a fourth aspect of the present disclosure is the cleaning device according to any one of the first to third aspects, further comprising a heating unit that heats the filter 47, and the first fluid supply unit 71 supplies the first fluid C1 to the heated filter 47. This makes it possible to remove solidified polyester and impurities adhering to the filter.

[0132] A cleaning device according to a fifth aspect of the present disclosure is the cleaning device according to any one of the first to fourth aspects, further comprising a heating unit that heats the first fluid C1, and the first fluid supply unit 71 supplies the heated first fluid C1, thereby removing solidified polyester and impurities adhering to the filter.

[0133] A cleaning device according to a sixth aspect of the present disclosure is the cleaning device according to any one of the first to fifth aspects, wherein the second fluid C2 is an acidic or alkaline liquid, thereby making it possible to remove impurities adhering to the filter.

[0134] A cleaning device according to a seventh aspect of the present disclosure is the cleaning device according to any one of the first to sixth aspects, further including a third fluid supply unit 73 that supplies a third fluid C3 for cleaning the filter 47 to the storage container 60 after the second fluid supply unit 72 supplies the second fluid C2 to the storage container 60. This makes it possible to remove the second fluid that has removed impurities adhering to the filter.

[0135] A cleaning device according to an eighth aspect of the present disclosure is the cleaning device according to the seventh aspect, wherein the third fluid C3 is ion-exchanged water, thereby making it possible to remove the second fluid from which impurities adhering to the filter have been removed.

[0136] A separation system according to a ninth aspect of the present disclosure includes a separation system main body that monomerizes the polyester contained in the polyester raw material Pm to produce monomers, and a cleaning device according to any one of the first to eighth aspects that cleans the filter 47 of the separation system main body.

[0137] According to the present disclosure, the first fluid supply unit supplies the first fluid to the container, thereby removing solidified polyester from the filter. After the first fluid supply unit supplies the first fluid to the container, the second fluid supply unit supplies the second fluid to the container. This also removes impurities adhering to the filter. Therefore, foreign matter can be stably removed.

[0138] A cleaning method according to a tenth aspect of the present disclosure is a cleaning method for cleaning a filter having solidified polyester and impurities attached thereto, and includes the steps of placing the filter 47 in a storage container 60, supplying a first fluid C1 to the storage container 60 to remove the solidified polyester from the filter 47, and, after supplying the first fluid C1 to the storage container 60, supplying a second fluid C2 to the storage container 60 to remove the impurities from the filter 47.

[0139] According to the present disclosure, the first fluid supply unit supplies the first fluid to the container, thereby removing solidified polyester from the filter. After the first fluid supply unit supplies the first fluid to the container, the second fluid supply unit supplies the second fluid to the container. This also removes impurities adhering to the filter. Therefore, foreign matter can be stably removed.

[0140] Although the embodiments of the present invention have been described above, the embodiments are not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the scope of what is called equivalents. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments. [Explanation of symbols]

[0141] 1 Separation System 12 Melting part 13 Solid-liquid separation section 14 Reaction solvent reservoir 16 Reaction section 18 Separation part 20 Storage section 22 Discharge section 26 Removal part 26a Filter 26b Adsorption tower 30, 30A, 80 control section 40, 60 storage container 41, 61 Lid 42, 62 1st space 43, 63 storage section 44, 64 2nd space 45, 65 Partition material 47 filters 48 Housing 66 Differential pressure gauge 70 Supply section 71 1st fluid supply section 72 Second fluid supply section 73 Third fluid supply section 100, 100A, 100B, 100C cleaning equipment 102 Heating section C1 1st fluid C2 2nd fluid C3 3rd fluid D and E monomers M reaction solvent P Polyester solution Pd solution Pm polyester raw material R impurity R1 First impurity R2 Second impurity R3 Third impurity

Claims

1. a container for storing the filter to which the solidified polyester and impurities are attached; a first fluid supply unit that supplies a first fluid to the storage container to remove the solidified polyester from the filter; a second fluid supply unit that supplies a second fluid to the storage container after the first fluid supply unit has supplied the first fluid to the storage container, the second fluid removing the impurities from the filter; Equipped with Cleaning equipment.

2. the first fluid supply unit backwashes the filter in the storage container with the first fluid; The second fluid supply unit backwashes the filter in the container with the second fluid. The cleaning device according to claim 1 .

3. 3. The cleaning device according to claim 1, wherein the first fluid is a liquid that dissolves the polyester.

4. Further, a heating unit that heats the filter is provided. The cleaning device according to claim 1 or 2, wherein the first fluid supply unit supplies the first fluid to the heated filter.

5. The cleaning apparatus according to claim 1 or 2, further comprising a heating unit that heats the first fluid, wherein the first fluid supply unit supplies the heated first fluid.

6. 3. The cleaning device according to claim 1, wherein the second fluid is an acidic or alkaline liquid.

7. 3. The cleaning device according to claim 1, further comprising a third fluid supply unit that supplies a third fluid to the storage container after the second fluid supply unit has supplied the second fluid to the storage container, the third fluid being used to clean the filter.

8. The cleaning device according to claim 7 , wherein the third fluid is ion-exchanged water.

9. a separation system main body that monomerizes polyester contained in the polyester raw material to produce monomers; A separation system comprising: the cleaning device according to claim 1 or 2, which cleans the filter of the separation system body.

10. 1. A cleaning method for cleaning a filter to which solidified polyester and impurities have adhered, comprising the steps of: placing the filter in a storage container; supplying a first fluid to the reservoir that removes the solidified polyester from the filter; and after supplying the first fluid to the container, supplying a second fluid to the container that removes the impurities from the filter. Cleaning method.

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