Storage system

Abstract

To appropriately store liquid containing an object.SOLUTION: A storage system includes: a solution tank for storing object liquid containing a liquid form object; a gas exhaust pipe connected to the solution tank to discharge gas in the solution tank; and a cooling mechanism for cooling a partial section of the gas exhaust pipe to deposit a gaseous object contained in the gas as a solid.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a storage system.

Background Art

[0002] Techniques for separating and extracting a target object from a liquid containing the target object are known. Patent Document 1 describes a technique for cooling a carboxylic acid-containing liquid to crystallize and extract the carboxylic acid.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, in a tank for storing a liquid containing a target object, a pipe for discharging the gas in the tank may be provided. Vaporized target object may also flow through this pipe. If the vaporized target object is cooled due to the influence of the external environment or the like, the target object may solidify and precipitate in the target object pipe, resulting in the risk of pipe blockage. As a result, there is a risk that the liquid containing the target object cannot be properly stored.

[0005] The present disclosure solves the above-described problems and aims to provide a storage system capable of properly storing a liquid containing a target object.

Means for Solving the Problems

[0006] To solve the above-described problems and achieve the object, a storage system according to the present disclosure includes a solution tank for storing a target liquid containing a liquid target object, a gas exhaust pipe connected to the solution tank for discharging the gas in the solution tank, and a cooling mechanism for cooling a part of a section of the gas exhaust pipe to precipitate the gaseous target object contained in the gas as a solid.

Advantages of the Invention

[0007] According to the present disclosure, a liquid containing an object can be appropriately stored.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited by this embodiment, and when there are multiple embodiments, those configured by combining each embodiment are also included.

[0010] (Recycling Process) FIG. 1 is a schematic diagram of a polyester recycling process according to the present embodiment. In the present embodiment, a process of recycling (reproducing) the polyester raw material Pm is performed by depolymerizing the polyester raw material Pm into monomers and then repolymerizing the monomers. Specifically, as shown in FIG. 1, the polyester raw material Pm is flaked (step S100), dissolved in a reaction solvent M and depolymerized (step S102), the monomers of the depolymerized polyester are purified (separated) to produce a monomer D derived from a carboxylic acid and a monomer E of an alcohol component (step S104), the monomer D is hydrolyzed to separate the reaction solvent M (step S106), and the monomer F produced by hydrolysis of the monomer D and the monomer E are polymerized (step S108) to reproduce the polyester raw material Pm. Note that the recycling process employing the separation system 1 of the present embodiment may omit the flaking in step S100, or may perform only the process of recovering the monomers D, E shown in step S104 and the monomer F shown in step S106 without performing the repolymerization process as in step S108.

[0011] (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, and examples thereof 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, but also includes components other than the polyester component. Examples of the components other than polyester contained in the polyester raw material Pm include plastics such as polyethylene, polystyrene, polypropylene, and polyvinyl chloride other than polyester, metals, dyes, pigments, and polymerization catalysts. Examples of the polyester raw material Pm also include clothes in which polyester and other components are knitted in a fibrous form. Hereinafter, the components other than polyester contained in the polyester raw material Pm are regarded as impurities.

[0012] (Reaction solvent) The reaction solvent M is a solvent that reacts with polyester to depolymerize the polyester. The reaction solvent M may be, for example, at least one of methanol, ethanol, water, and ethylene glycol.

[0013] (Monomer derived from carboxylic acid) The monomer D derived from carboxylic acid is a monomer having a carboxyl group generated by the depolymerization reaction of polyester. The monomer D may be, for example, dimethyl carboxylate or diethyl carboxylate. Furthermore, the monomer D is preferably a monomer of terephthalic acid, and may be, for example, dimethyl terephthalate (DMT).

[0014] (Monomer of alcohol component) Monomer E of the alcohol component is a monomer of the alcohol component generated by the depolymerization reaction of the polyester. Monomer E may be, for example, a dihydroxy compound (dihydric alcohol), and more specifically, it may be ethylene glycol (EG).

[0015] Hereinafter, the case where the polyester is PET, the reaction solvent M is methanol, the monomer D is DMT, and the monomer E is EG will be described as an example.

[0016] (First Embodiment) (Separation System) FIG. 2 is a schematic diagram of the separation system according to the first embodiment. The separation system 1 according to the first embodiment is a system that monomerizes the polyester contained in the polyester raw material Pm to generate monomers D and E. As shown in FIG. 2, the separation system 1 includes a raw material storage unit 10, a dissolution unit 12, a solid-liquid separation unit 13, a solvent storage unit 14, a reaction unit 16, a separation unit 18, a control unit 30, and a storage system 200.

[0017] Hereinafter, the Z direction is the vertical direction (up and down direction). The upward direction in the vertical direction of the Z direction is the Z1 direction, and the downward direction in the vertical direction is the Z2 direction. Also, the horizontal direction is a direction orthogonal to the Z direction (vertical direction).

[0018] (Raw Material Storage Unit) The raw material storage section 10 is a tank (hopper) into which the polyester raw material Pm is introduced and where the polyester raw material Pm is stored. In the present embodiment, the flaked polyester raw material Pm is stored in the raw material storage section 10, but the shape and size of the polyester raw material Pm may be arbitrary. The raw material storage section 10 is connected to the dissolution section 12 via the introduction pipe 10a. The polyester raw material Pm in the raw material storage section 10 is supplied to the dissolution section 12 through the introduction pipe 10a. The introduction pipe 10a is provided with an adjustment section 10b for adjusting the amount of the polyester raw material Pm supplied from the raw material storage section 10 to the dissolution section 12. The adjustment section 10b is, for example, an on-off valve. In the open state, the polyester raw material Pm in the raw material storage section 10 is supplied to the dissolution section 12, and in the closed state, the supply of the polyester raw material Pm in the raw material storage section 10 to the dissolution section 12 is stopped. However, the adjustment section 10b is not limited to being an on-off valve and may be any mechanism capable of adjusting the supply of the polyester raw material Pm to the dissolution section 12. Further, the polyester raw material Pm may be supplied directly to the dissolution section 12 without passing through the raw material storage section 10, the introduction pipe 10a, and the adjustment section 10b.

[0019] (Dissolution section) The dissolution section 12 is a tank in which the dissolved solution Pd is stored. The dissolved solution Pd is a solution formed by mixing the polyester raw material Pm and the monomer D. Here, the polyester component contained in the polyester raw material Pm dissolves in the monomer D, but impurities, which are components other than polyester contained in the polyester raw material Pm, remain without dissolving in the monomer D. Therefore, it can be said that the dissolved solution Pd contains the polyester solution P in which the polyester contained in the polyester raw material Pm is dissolved in the monomer D and the impurities contained in the polyester raw material Pm.

[0020] The monomer D and the polyester raw material Pm are supplied to the dissolution section 12. In the dissolution section 12, the polyester contained in the polyester raw material Pm dissolves in the monomer D, while impurities remain without dissolving in the monomer D, generating a polyester solution P and a dissolution liquid Pd containing impurities. By dissolving the polyester in the monomer D in this way, the viscosity can be reduced and the fluidity can be improved, and the polyester can be easily led out to the reaction section 16. Note that the polyester solution P is not limited to the case where the entire amount of the polyester is dissolved in the monomer D, and at least a part of the polyester may be in a state of not being dissolved in the monomer D. Further, among the components other than the polyester contained in the polyester raw material Pm, if there are components that can be dissolved in the monomer D, the polyester solution P may also contain the components dissolved in the monomer D.

[0021] The dissolution section 12 is connected to a first reaction section 16A, which will be described later, via an introduction pipe 12a. The dissolution liquid Pd in the dissolution section 12 is supplied to the first reaction section 16A through the introduction pipe 12a. Further, a supply section 12a1 is provided in the introduction pipe 12a. The supply section 12a1 is a mechanism for supplying the polyester solution P in the dissolution section 12 to the first reaction section 16A, and is a pump in the present embodiment.

[0022] In this embodiment, a heating unit 12A is provided in the dissolution unit 12. By heating the inside of the dissolution unit 12, the heating unit 12A heats the monomer D and the polyester raw material Pm supplied to the dissolution unit 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 such a predetermined temperature, the polyester contained in the polyester raw material Pm can be appropriately 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 also include components that melt when heated to a predetermined temperature (a temperature at which the polyester can be dissolved in the monomer D). Therefore, when the impurities contain components that melt when heated to the predetermined temperature, a part of them is in a molten state and is contained in the dissolution liquid Pd. In this embodiment, the heating unit 12A is provided in the dissolution unit 12, but the position where the heating unit 12A is provided is not limited thereto and is arbitrary.

[0023] (Solvent storage section) The solvent storage section 14 is a tank into which the reaction solvent M is introduced and stored. The solvent storage section 14 is connected to the reaction section 16 via an introduction pipe 14a. The reaction solvent M in the solvent storage section 14 is supplied to the reaction section 16 through the introduction pipe 14a. More specifically, a heating and pressurizing section 14b for pressurizing and heating the reaction solvent M is provided in the introduction pipe 14a. By pressurizing and heating the reaction solvent M, the heating and pressurizing section 14b makes the reaction solvent M in 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).

[0024] (Reaction section) The reaction section 16 is a container into which the dissolution liquid Pd and the reaction solvent M are introduced, and the polyester in the dissolution liquid Pd is depolymerized. The reaction section 16 includes a first reaction section 16A and a second reaction section 16B.

[0025] (First reaction section) The first reaction section 16A is formed within the reaction section 16. In the present embodiment, the first reaction section 16A can be said to be the location within the reaction section 16 filled with a packing material. As the packing material for the first reaction section 16A, known materials used in gas-liquid or liquid-liquid contact devices can be used. For example, the same packing material as that used in a contact device for contacting heavy oil and water to extract active ingredients can be used. Specific examples of the packing material include pipes made of SUS, etc., Raschig rings, Berl saddles, Telarets, balls, etc.

[0026] An introduction pipe 12a is connected to the first reaction section 16A. More specifically, an inlet 16C, which is an opening through which the dissolved solution Pd from the dissolution section 12 is introduced into the introduction pipe 12a, is connected to the first reaction section 16A. The inlet 16C is connected to the surface 16A1 on the first direction D1 side of the first reaction section 16A. The introduction pipe 12a is connected to the surface 16A1 such that the inlet 16C opens facing the second direction D2 side opposite to the first direction D1. Thus, in the present embodiment, the inlet 16C opening facing the second direction D2 side is connected to the surface 16A1 of the first reaction section 16A, but it is not limited thereto. For example, the inlet 16C may not be directly connected to the first reaction section 16A, and the inlet 16C opening facing the second direction D2 side may be connected to the first direction D1 side of the surface 16A1 of the first reaction section 16A within the reaction section 16.

[0027] The introduction pipe 14a is connected to the reaction section 16. More specifically, an inlet 16D, which is an opening through which the reaction solvent M from the solvent storage section 14 is introduced into the introduction pipe 14a, is connected to the reaction section 16. The inlet 16D is connected to the second direction D2 side of the surface 16A2 of the first reaction section 16A. The introduction pipe 14a is connected to the second direction D2 side of the surface 16A2 such that the inlet 16D faces the first direction D1 side or opens from the side surface toward the center side. Thus, in the present embodiment, the inlet 16D that faces the first direction D1 side or opens from the side surface toward the center side is connected to the second direction D2 side of the surface 16A2 of the first reaction section 16A, but it is not limited thereto. 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.

[0028] Thus, in the present embodiment, the inlet 16C through which the dissolved solution Pd is introduced opens facing the second direction D2, and the inlet 16D through which the reaction solvent M is introduced faces the first direction D1 or opens from the side surface toward the center side. Therefore, the dissolved solution Pd and the reaction solvent M are introduced into the first reaction section 16A in directions facing each other.

[0029] The dissolved solution Pd introduced from the inlet 16C into the first reaction section 16A moves on the surface of the packing material in the first reaction section 16A in the second direction D2. On the other hand, the reaction solvent M in a supercritical state or a subcritical state (pressurized gas or pressurized liquid) introduced from the inlet 16D moves in the first reaction section 16A in the first direction D1. In the first reaction section 16A, the reaction solvent M in a supercritical state or a subcritical state (pressurized gas or pressurized liquid) comes into contact with the dissolved solution Pd. The polyester in the dissolved solution Pd is depolymerized (molecular weight reduced) by the reaction solvent M, and the depolymerized polyester is extracted by the reaction solvent M in a supercritical state or a subcritical state (pressurized gas or pressurized liquid). Hereinafter, the polyester depolymerized in the first reaction section 16A is referred to as the first depolymerized polyester P1, and a 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) is referred to as the first solvent M1. The first solvent M1 containing the first depolymerized polyester P1 proceeds to the first direction D1 side of the first reaction section 16A and is led out to the first direction D1 side of the first reaction section 16A.

[0030] Note that the first depolymerized polyester P1 includes monomers D and E generated by depolymerization of the polyester in the dissolved solution Pd, monomer D originally mixed in the dissolved solution Pd, and oligomers generated by depolymerization of the polyester. The oligomers here refer to oligomers derived from carboxylic acids or alcohol components that have not been monomerized but have been depolymerized from the polyester (oligomers derived from carboxylic acids or alcohol components with a molecular weight smaller than that of the polyester). In addition, the oligomers contained in the residual substance R in the polyester solution P are also depolymerized by the reaction solvent M. Therefore, the first depolymerized polyester P1 also includes the depolymerized residual substance R. The depolymerized residual substance R is oligomers contained in the residual substance that have been depolymerized, monomers D and E obtained by depolymerization of the oligomers contained in the residual substance, and the like.

[0031] (Second reaction section) The second reaction section 16B is formed within the reaction section 16, and the second reaction section 16B is formed at a location where the first solvent M1 is derived from the first reaction section 16A. In the present embodiment, since the first solvent M1 is derived toward the first direction D1, the second reaction section 16B can be said to be a space formed on the first direction D1 side of the first reaction section 16A.

[0032] In the second reaction section 16B, the first depolymerized polyester P1 contained in the first solvent M1 is further depolymerized (molecular weight reduced) 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 is referred to as the second depolymerized polyester P2, and a mixture of the second depolymerized polyester P2 and the reaction solvent M (reaction solvent M in which the second depolymerized polyester P2 is dissolved) is referred to as the second solvent M2. A lead-out pipe 16a is connected to the second reaction section 16B. More specifically, a lead-out port 16E, which is an opening from which the second solvent M2 from the second reaction section 16B is led out, of the lead-out pipe 16a 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 led out to the outside of the second reaction section 16B through the lead-out pipe 16a from the lead-out port 16E.

[0033] Note that the second depolymerized polyester P2 includes monomers D and E in the first depolymerized polyester P1, monomers D and E generated by depolymerization of oligomers in the first depolymerized polyester P1, and oligomers generated by depolymerization of the first depolymerized polyester P1.

[0034] At the bottom of the reaction section 16, a discharge pipe 16b is connected. More specifically, at the bottom of the reaction section 16, a discharge port 16F, which is an opening through which non-extracts (described later) in the reaction section 16 are discharged, of the discharge pipe 16b is connected. From the discharge port 16F, non-extracts containing impurities such as metal compounds not extracted into the reaction solvent M and residues of undecomposed polyester not extracted into the reaction solvent M are discharged. That is, the non-extracts at the bottom of the reaction section 16 are discharged to the outside of the reaction section 16 through the discharge pipe 16b from the discharge port 16F. The non-extracts discharged from the discharge port 16F can be said to be the components remaining in the first reaction section 16A and the second reaction section 16B without being led to the separation section 18 as the second solvent M2 (the reaction solvent M in which the second depolymerized polyester P2 is dissolved) in the polyester solution P.

[0035] Further, the reaction section 16 may be provided with a heating section for heating the inside of the reaction section 16 and a pressurizing section for maintaining the pressure inside the reaction section 16 at a predetermined value or more. The temperature inside the reaction section 16 is preferably set to 250°C or more and 400°C or less, and more preferably 250°C or more and 350°C or less. Also, the pressure inside the reaction section 16 is preferably 1 MPa or more and 30 MPa or less, and more preferably 6 MPa or more and 25 MPa or less. The pressurizing section and the heating section may be controlled by the control section 30.

[0036] (Separation section) The separation section 18 is introduced with the second solvent M2 containing the second depolymerized polyester P2, and separates the second solvent M2 into the reaction solvent M, the monomer D derived from the carboxylic acid contained in the second depolymerized polyester P2, the monomer E of the alcohol component contained in the second depolymerized polyester P2, and the residual substance R. The separation section 18 separates the second solvent M2 into the monomer D, the monomer E, and the residual substance R by distilling the second solvent M2. The residual substance R is a component other than the reaction solvent M, the monomer D, and the monomer E in the second solvent M2 and contains oligomers.

[0037] In the present embodiment, the separation section 18 includes a first separation section 18A, a second separation section 18B, and a third separation section 18C.

[0038] The first separation unit 18A is a separation column connected to the lead-out pipe 16a. The second solvent M2 containing the second depolymerized polyester P2 is introduced into the first separation unit 18A via the lead-out pipe 16a. The first separation unit 18A separates the second solvent M2 into a low-boiling component and a high-boiling component having a boiling point higher than that of the low-boiling component. For example, in the first separation unit 18A, the second solvent M2 may be set at a predetermined temperature, and the component that has become a gas may be regarded as the low-boiling component, and the liquid component may be regarded as the high-boiling component. The lead-out pipes 18Aa and 18Ab are connected to the first separation unit 18A. The low-boiling component is led out from the lead-out pipe 18Aa, and the high-boiling component is led out from the lead-out pipe 18Ab.

[0039] The second separation unit 18B is a separation column connected to the first separation unit 18A via the lead-out pipe 18Aa. The low-boiling component is introduced into the second separation unit 18B via the lead-out pipe 18Aa. The second separation unit 18B separates the low-boiling component into the reaction solvent M and the monomer E. The lead-out pipes 18Ba and 18Bb are connected to the second separation unit 18B. The reaction solvent M is led out from the lead-out pipe 18Ba, and the monomer E is led out from the lead-out pipe 18Bb. Note that the lead-out pipe 18Ba is connected to the second separation unit 18B and the solvent storage unit 14. Therefore, the reaction solvent M led out from the second separation unit 18B is returned to the solvent storage unit 14 and reused for the depolymerization of the polyester.

[0040] The third separation unit 18C is a separation column connected to the first separation unit 18A via the lead-out pipe 18Ab. The high-boiling component is introduced into the third separation unit 18C via the lead-out pipe 18Ab. The third separation unit 18C separates the high-boiling component into a residue with an even higher boiling point, a low-boiling component containing the reaction solvent M and the monomer E, and the monomer D. The lead-out pipes 18Ca, 18Cb, and 18Cc are connected to the third separation unit 18C. The lead-out pipe 18Ca is connected to the second separation unit 18B. The low-boiling component separated within the third separation unit 18C is led out to the second separation unit 18B via the lead-out pipe 18Ca. Also, the monomer D separated within the third separation unit 18C is led out from the lead-out pipe 18Cb and introduced into the temporary storage unit 70. The residue separated within the third separation unit 18C is led out from the lead-out pipe 18Cc.

[0041] A introducing pipe 18Cd is connected to the third separation part 18C. The introducing pipe 18Cd is also connected to the dissolution part 12, and introduces the monomer D derived from the third separation part 18C into the dissolution part 12. In the example of FIG. 2, the introducing pipe 18Cd branches off from the leading-out pipe 18Cb. An adjusting part 18Ce for adjusting the amount of the monomer D supplied from the third separation part 18C to the dissolution part 12 is provided in the introducing pipe 18Cd. The adjusting part 18Ce is, for example, an on-off valve. In the open state, the monomer D is supplied to the dissolution part 12, and in the closed state, the supply of the monomer D to the dissolution part 12 is stopped. However, the adjusting part 18Ce is not limited to being an on-off valve, and may be any mechanism capable of adjusting the supply of the monomer D to the dissolution part 12. In the present embodiment, the adjusting part 18Ce is provided at the branching position of the introducing pipe 18Cd from the leading-out pipe 18Cb, but the position where it is provided is not limited to that and may be arbitrary. Further, the introducing pipe 18Cd may not be connected to the leading-out pipe 18Cb and may be directly connected to the third separation part 18C. Also, for example, a storage part (tank) for storing the monomer D may be provided in the leading-out pipe 18Cb, and the introducing pipe 18Cd may be connected to the storage part.

[0042] A introducing pipe 18Cf is connected to the third separation part 18C. The introducing pipe 18Cf is also connected to the dissolving part 12, and introduces the residual substance R derived from the third separation part 18C into the dissolving part 12. In the example of FIG. 2, the introducing pipe 18Cf branches from the leading-out pipe 18Cc. An adjusting part 18Cg for adjusting the amount of the residual substance R supplied from the third separation part 18C to the dissolving part 12 is provided on the introducing pipe 18Cf. The adjusting part 18Cg is, for example, an on-off valve. In the open state, the residual substance R is supplied to the dissolving part 12, and in the closed state, the supply of the residual substance R to the dissolving part 12 is stopped. However, the adjusting part 18Cg is not limited to being an on-off valve, and may be any mechanism capable of adjusting the supply of the residual substance R to the dissolving part 12. In the present embodiment, the adjusting part 18Cg is provided at the branching position of the introducing pipe 18Cf from the leading-out pipe 18Cc, but the position where it is provided is not limited thereto and may be arbitrary. Further, the introducing pipe 18Cf may not be connected to the leading-out pipe 18Cc and may be directly connected to the third separation part 18C.

[0043] For example, a storage part (tank) for storing the residual substance R may be provided in the leading-out pipe 18Cc, and the introducing pipe 18Cf may be connected to the storage part. Further, a filter for collecting foreign matters in the residual substance R while allowing oligomers in the residual substance R to pass through may be provided on the introducing pipe 18Cf.

[0044] (Temporary storage part) The temporary storage part 70 is, for example, a tank, and temporarily stores the monomer D supplied from the third separation part 18C. The temporary storage part 70 is connected to the third separation part 18C via the leading-out pipe 18Cb. The temporary storage part 70 is connected to the dissolving tank 82 via the leading-out pipe 72. The temporary storage part 70 supplies the temporarily stored monomer D to the dissolving tank 82.

[0045] (Dissolving tank) The dissolution tank 82 is a tank that stores the dissolution liquid L in which the monomer D is dissolved. The dissolution tank 82 is connected to the temporary storage unit 70 via the outlet pipe 72. The monomer D containing impurities, which has been separated by the third separation unit 18C, is introduced into the dissolution tank 82 from the temporary storage unit 70. Further, a solvent for dissolving the monomer D is introduced into the dissolution tank 82. As a result, in the dissolution tank 82, the monomer D is dissolved in the solvent and stored as the dissolution liquid L. Although any liquid may be used as the solvent, methanol is used in the present embodiment.

[0046] The dissolution tank 82 is connected to the adjustment unit 86 and the crystallization tank 90 via the inlet pipe 84. The dissolution liquid L stored in the dissolution tank 82 is introduced into the crystallization tank 90 via the inlet pipe 84 and the adjustment unit 86. Note that the dissolution tank 82 is located in the Z1 direction (vertically upward) with respect to the crystallization tank 90 described later. However, the positional relationship in the Z direction between the dissolution tank 82 and the crystallization tank 90 is not limited to this and may be arbitrary.

[0047] (Inlet pipe) The inlet pipe 84 extends downward from the dissolution tank 82 toward the crystallization tank 90. The inlet pipe 84 connects the opening of the dissolution tank 82 and the crystallization tank 90. The dissolution liquid L in the dissolution tank 82 flows through the inlet pipe 84 and the adjustment unit 86 into the crystallization tank 90.

[0048] (Adjustment unit) The adjustment unit 86 is a device that reduces the pressure of the dissolution liquid L. The adjustment unit 86 is connected to the inlet pipe 84 and the crystallization tank 90. The adjustment unit 86 reduces the pressure of the dissolution liquid L introduced from the dissolution tank 82 via the inlet pipe 84 and introduces the decompressed dissolution liquid L into the crystallization tank 90.

[0049] The adjustment unit 86 is a pressure reducing valve in the present embodiment. The adjustment unit 86 may have any structure as long as it is a pressure reducing valve, but it is an angle valve in the present embodiment. In the present embodiment, the adjustment unit 86 is directly connected to the crystallization tank 90.

[0050] The dissolution liquid L introduced into the adjustment unit 86 is introduced into the crystallization tank 90 in a state of reduced pressure by the adjustment unit 86. Since the temperature of the reduced-pressure dissolution liquid L decreases, the monomer HD to be separated crystallizes from the reduced-pressure dissolution liquid L.

[0051] In addition, in this embodiment, the adjustment unit 86 is directly connected to the crystallization tank 90, but it is not limited thereto, and a pipe connecting the adjustment unit 86 and the crystallization tank 90 may be provided between the adjustment unit 86 and the crystallization tank 90.

[0052] (Crystallization tank) The crystallization tank 90 is a tank into which the dissolution liquid L depressurized by the adjustment unit 86 is introduced, and in which the separation target (here, monomer HD) crystallizes from the dissolution liquid L inside. The dissolution liquid L depressurized by the adjustment unit 86 is introduced into the crystallization tank 90. In this way, the depressurized dissolution liquid L is introduced into the crystallization tank 90 and stored in a state where the dissolution liquid L is depressurized. That is, the crystallization tank 90 can be said to be a flash-type crystallization tank in which the internal pressure is depressurized compared to the external pressure.

[0053] A discharge pipe 121 for discharging the slurry S is connected to the crystallization tank 90. The slurry S is a slurry containing the crystallized monomer HD and the dissolution liquid L from which the monomer HD has been removed.

[0054] Inside the crystallization tank 90, a baffle 110 for rectifying the flow of the dissolution liquid L in the crystallization tank 90 is provided. The shape, mounting position, and number of the baffle 110 are arbitrary. In this embodiment, the baffle 110 is provided on the inner wall surface of the crystallization tank 90. More specifically, it is a plate-like member extending in the Z direction on the inner wall surface of the side wall 90b. However, the baffle 110 is not an essential component and may not be provided inside the crystallization tank 90.

[0055] (Stirring part) The stirring unit 100 is provided in the crystallization tank 90 and is a device that rotates and stirs the inside of the crystallization tank 90 when a driving unit (for example, a motor) is driven. In the present embodiment, the stirring blades are located on the Z2 direction side rather than the adjustment unit 86. Further, the stirring blades are located on the Z1 direction side rather than the bottom surface portion of the crystallization tank 90 and are provided at a position facing the bottom surface portion (that is, a position overlapping the bottom surface portion when viewed from the Z direction). Further, it is preferable that the stirring unit 100 is provided at the central position of the crystallization tank 90 when viewed from the Z direction. That is, it is preferable that the central axis of the stirring unit 100 coincides with the central axis of the crystallization tank 90.

[0056] (Solid-liquid separation unit) The solid-liquid separation unit 120 is connected to the crystallization tank 90 via a discharge pipe 121. The slurry S (the solution L in which the monomer HD has crystallized) generated in the crystallization tank 90 is introduced into the solid-liquid separation unit 120 from the crystallization tank 90 via the discharge pipe 121. The solid-liquid separation unit 120 separates the introduced slurry S into a solid-liquid separation. The solid-liquid separation unit 120 separates the slurry S into a solid component to be separated and a liquid component. In the present embodiment, the solid-liquid separation unit 120 separates the slurry S into the monomer HD and the solution L from which the monomer HD has been removed. The solution L from which the monomer HD has been removed is led out from a lead-out pipe 123 connected to the solid-liquid separation unit 120 and processed. The solid-liquid separation unit 120 is, for example, a centrifuge, and may separate the separation target from the solution L by centrifugation that stirs the inside of the solid-liquid separation unit 120 around a predetermined axis and moves the separation target to the outside in the radial direction of the rotation axis. The solid-liquid separation unit 120 only needs to be able to separate the separation target from the solution L and is not limited to centrifugation. For example, the solid-liquid separation unit 120 may separate the separation target from the solution L by a filter.

[0057] (Melting tank) The melting tank 130 is connected to the solid-liquid separation unit 120 via a lead-out pipe 122. Further, the melting tank 130 is connected to the melting temporary storage tank 140 via a supply pipe 132. The melting tank 130 melts (fuses) the highly pure monomer HD solid-liquid separated from the slurry S. The melting tank 130 melts the monomer HD into a liquid state and supplies it to the melting temporary storage tank 140 via the supply pipe 132.

[0058] (Melting Temporary Storage Tank) The melting temporary storage tank 140 is connected to the hydrolysis separation reaction section 150 via a discharge pipe 142. The melting temporary storage tank 140 is a tank that temporarily stores the monomer HD melted in the melting tank 130. The melting temporary storage tank 140 supplies the stored monomer HD to the hydrolysis separation reaction section 150.

[0059] The monomer HD hydrolyzed in the hydrolysis separation reaction section 150 becomes high-purity terephthalic acid (PTA). Thereafter, the PTA is stored in a hopper through a crystallization step and a drying step (not shown).

[0060] (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 the polyester raw material Pm supplied from the raw material storage unit 10 to the melting unit 12. Further, when the solid-liquid separation unit 13 is provided with a drive unit, the control unit 30 controls the operation of the solid-liquid separation unit 13. The control unit 30 controls the supply unit 12a1 to control the amount of the dissolved liquid Pd supplied from the melting unit 12 to the reaction unit 16. The control unit 30 controls the heating and pressurizing unit 14b to make the reaction solvent M in a supercritical state or a subcritical state (pressurized gas or pressurized liquid), and controls the supply amount of the reaction solvent M in the supercritical state or the subcritical state (pressurized gas or pressurized liquid) to the reaction unit 16. The control unit 30 controls the adjustment unit 18Ce to control the supply amount of the monomer D to the melting unit 12. The control unit 30 controls the adjustment unit 18Cg to control the supply amount of the residual substance R to the melting unit 12. The control unit 30 adjusts the adjustment unit 86 to control the flow rate of the dissolved liquid L to the crystallization tank 90 while depressurizing the dissolved liquid L. The control unit 30 controls the rotation of the stirring unit 100. The control unit 30 controls the operation of the storage system 200 described later.

[0061] The control unit 30 is a computer in this embodiment, 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 arithmetic content and programs by the processor. The control unit 30 reads a program from the storage unit to execute the control of the separation system 1.

[0062] However, the separation system 1 is not limited to being automatically controlled by the control unit 30. For example, at least some of the processes may be controlled by the operation of an operator.

[0063] (Operation of the separation system) 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 mixes the polyester raw material Pm and the monomer D in the dissolution unit 12 to generate a dissolution liquid Pd. The control unit 30 controls the supply unit 12a1 to introduce the dissolution liquid Pd generated in the dissolution unit 12 into the first reaction unit 16A.

[0064] The control unit 30 controls the heating and pressurizing unit 14b to supply the reaction solvent M in a supercritical state or a subcritical state (pressurized gas or pressurized liquid) to the reaction unit 16. The control unit 30 preferably sets the reaction solvent M to be 250°C or higher and 400°C or lower, and more preferably 250°C or higher and 350°C or lower. The control unit 30 preferably sets the reaction solvent M to be 1 MPa or higher and 30 MPa or lower, and more preferably 6 MPa or higher and 25 MPa or lower.

[0065] In this way, by supplying the dissolution liquid Pd and the reaction solvent M to the reaction section 16, in the first reaction section 16A, the polyester contained in the dissolution liquid Pd is depolymerized to produce the first depolymerized polyester P1. Then, in the second reaction section 16B, the first depolymerized polyester P1 is further depolymerized to produce the 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, the monomer D, the monomer E, and the residual substances in the first separation section 18A, the second separation section 18B, and the third separation section 18C.

[0066] The control unit 30 controls the adjustment unit 86 to supply the dissolution liquid L to the adjustment unit 86, depressurize the dissolution liquid L by the adjustment unit 86, and introduce the depressurized dissolution liquid L into the crystallization tank 90. Since the dissolution liquid L introduced into the crystallization tank 90 is depressurized, the monomer HD, which is the object, crystallizes from the dissolution liquid L in the crystallization tank 90.

[0067] The control unit 30 controls the storage system 200 described later. Specifically, the control unit 30 controls the switching between the cooling mechanism and the removal mechanism of the storage system, the adjustment of the valve unit, the driving of the driving unit of the removal mechanism, etc. The control content of the storage system 200 will be described later.

[0068] (Storage System) FIG. 3 is a schematic diagram for explaining the storage system according to the first embodiment. FIG. 4 is a schematic cross-sectional view of the cooling mechanism according to the first embodiment. The storage system 200 is a system for storing a target liquid, which is a liquid containing a liquid target object, and has a solution tank 210 for storing the target liquid. Here, the target object refers to a substance to be processed in the subsequent stage, for example, a substance to be separated from other substances in the subsequent stage. The target object may be any substance to be processed in the subsequent stage, for example, a substance having sublimability. In the present embodiment, the target object is the monomer D.

[0069] In this embodiment, the storage system 200 is provided in the separation system 1 and stores a target liquid containing the liquid monomer D. More specifically, the storage system 200 is provided in the separation system 1 at a location where the target liquid containing the liquid monomer D is stored. That is, in this embodiment, the storage system 200 is provided in at least one of the dissolution section 12 where the dissolution liquid Pd is stored, the temporary storage section 70 where the monomer D separated in the third separation section 18C is stored, and the molten temporary storage tank 140 where the monomer D (monomer HD) with increased purity by crystallization is stored. In other words, at least one of the dissolution section 12, the temporary storage section 70, and the molten temporary storage tank 140 can be said to be the solution tank 210 of the storage system 200. Preferably, the storage system 200 is provided in all of the dissolution section 12, the temporary storage section 70, and the molten temporary storage tank 140. However, the storage system 200 is not limited to the use of storing the target liquid containing the monomer D provided in the separation system 1, and may store the target liquid containing an arbitrary component object in a liquid state. For example, the storage system 200 may be provided in a tank that stores a target liquid containing organic substances or inorganic substances (for example, iodine) other than the monomer D.

[0070] Hereinafter, the storage system 200 according to this embodiment will be specifically described.

[0071] As shown in FIG. 3, the storage system 200 includes a solution tank 210 (in this embodiment, the dissolution section 12, the temporary storage section 70, and the molten temporary storage tank 140), a gas exhaust pipe 220, and a cooling mechanism 230. Further, the storage system 200 has a removal mechanism 240.

[0072] (Solution tank) The solution tank 210 is a tank that stores a target liquid L2 containing a liquid object. A target liquid introduction pipe 214 and a target liquid discharge pipe 216 are connected to the solution tank 210. A target liquid L2 containing a liquid object is introduced into the solution tank 210 from the target liquid introduction pipe 214, and the target liquid L2 is stored in the solution tank 210. Further, the target liquid L2 stored in the solution tank 210 is discharged from the target liquid discharge pipe 216. In the present embodiment, the target liquid introduction pipe 214 is connected to the side surface of the solution tank 210, but the connection position may be arbitrary, for example, it may be connected to the upper surface of the solution tank 210. The target liquid discharge pipe 216 is connected to the bottom surface of the solution tank 210, but the connection position may be arbitrary, for example, it may be connected to the side surface of the solution tank 210.

[0073] For example, when the solution tank 210 is the dissolution part 12, the introduction pipe 10a is the target liquid introduction pipe 214, the introduction pipe 12a is the target liquid discharge pipe 216, and a dissolution liquid Pd in which a monomer D, which is a liquid object, and a polyester raw material Pm are dissolved is supplied to and stored in the solution tank 210. Further, for example, when the solution tank 210 is the temporary storage part 70, the discharge pipe 18Cb is the target liquid introduction pipe 214, the discharge pipe 72 is the target liquid discharge pipe 216, and a monomer D, which is a liquid object, is supplied to and stored in the solution tank 210. Further, for example, when the solution tank 210 is the molten temporary storage tank 140, the supply pipe 132 is the target liquid introduction pipe 214, the discharge pipe 142 is the target liquid discharge pipe 216, and a monomer HD, which is a liquid object, is supplied to and stored in the solution tank 210.

[0074] Further, a pressure gauge 218 is provided in the solution tank 210. The pressure gauge 218 is a sensor provided in the solution tank 210 to measure the pressure inside the solution tank 210. In the present embodiment, the pressure gauge 218 is provided on the upper surface of the solution tank 210, but it may be provided at any position where the pressure inside the solution tank 210 can be measured.

[0075] (Gas supply pipe) A gas supply pipe 212 is connected to the solution tank 210. The gas supply pipe 212 is a pipe for supplying the seal gas Sg into the solution tank 210. In the present embodiment, the gas supply pipe 212 is connected to, for example, the upper surface of the solution tank 210, but the connection position is not limited to this and may be arbitrary. The seal gas Sg is continuously supplied into the solution tank 210 from the gas supply pipe 212. The seal gas Sg is a gas that does not react with the object (monomer D), and may be, for example, nitrogen gas or a noble gas (such as argon), and is nitrogen gas in the present embodiment.

[0076] (Gas exhaust pipe) A gas exhaust pipe 220 is connected to the solution tank 210. The gas exhaust pipe 220 is a pipe connected to the solution tank 210 for discharging the gas in the solution tank 210. In the present embodiment, the gas exhaust pipe 220 is connected to the upper surface of the solution tank 210, but the connection position is not limited to this and may be arbitrary. As shown in FIG. 4, the gas exhaust pipe 220 is connected to a side pipe 221. In this case, the gas in the solution tank 210 is introduced from the gas exhaust pipe 220 into the side pipe 221 and discharged from the side pipe 221 to the outside. The side pipe 221 extends in a direction intersecting the gas exhaust pipe 220. However, the side pipe 221 is not an essential component, and the gas exhaust pipe 220 may be directly connected to the outside.

[0077] (Discharge of gas) In this way, the seal gas Sg is supplied to the solution tank 210 from the gas supply pipe 212, and the gas in the solution tank 210 is discharged from the gas exhaust pipe 220. Therefore, the air present in the solution tank 210 is pushed out by the supply of the seal gas Sg and discharged from the gas exhaust pipe 220. Since the object (for example, monomer D) stored in the solution tank 210 may react with oxygen and deteriorate, the deterioration of the object can be suppressed by discharging the oxygen contained in the air by the seal gas Sg in this way. Note that the seal gas Sg supplied to the solution tank 210 is also discharged from the gas exhaust pipe 220. Hereinafter, the gas discharged from the gas exhaust pipe 220 is appropriately referred to as gas G.

[0078] Here, at least a part of the object (for example, monomer D) in the solution tank 210 may vaporize. The vaporized object is contained in the gas G and discharged from the gas exhaust pipe 220. However, since the object has a high sublimation property, for example, when a low-temperature section occurs in the gas exhaust pipe 220 due to the influence of the external environment or the like, the object vaporized in that section may solidify, and the gas exhaust pipe 220 may be blocked. As a result, there is a possibility that the liquid containing the object cannot be properly stored. On the other hand, in the present embodiment, the cooling mechanism 230 actively cools the inside of the gas exhaust pipe 220 to solidify the object. That is, if the object solidifies at an unexpected location inside the gas exhaust pipe 220, it becomes difficult to grasp the position of the solidified object and difficult to remove it. On the contrary, by solidifying the object at a predetermined location by the cooling mechanism 230, the position of the solidified object can be grasped, the solidified object can be appropriately removed, and the blockage of the gas exhaust pipe 220 can be appropriately suppressed.

[0079] (Cooling mechanism) The cooling mechanism 230 is a mechanism that cools a part of the gas exhaust pipe 220 and deposits the gaseous object contained in the gas as a solid. The cooling mechanism 230 is provided in a part of the gas exhaust pipe 220. The part of the gas exhaust pipe 220 where the cooling mechanism 230 is provided may be at any position among the entire section of the gas exhaust pipe 220. However, for example, it is preferably a section on the side connected to the solution tank 210 rather than the midpoint position in the axial direction of the gas exhaust pipe 220, and more preferably near the end of the gas exhaust pipe 220 connected to the solution tank 210. Further, when a side pipe 221 is connected to the gas exhaust pipe 220, a part of the section is preferably at a position between the end of the gas exhaust pipe 220 connected to the solution tank 210 and the connection point of the side pipe 221.

[0080] The structure of the cooling mechanism 230 may be arbitrary. In the present embodiment, it is a tubular member surrounding a part of the gas exhaust pipe 220. More specifically, as shown in FIGS. 3 and 4, the cooling mechanism 230 includes an introduction pipe 232, a pipe portion 234, and a lead-out pipe 236.

[0081] The pipe section 234 is a tubular member that surrounds a partial section of the gas exhaust pipe 220. The introduction pipe 232 is a pipe connected to the pipe section 234. The discharge pipe 236 is a pipe connected to a location different from the refrigerant introduction pipe of the pipe section 234. The cooling mechanism 230 introduces the refrigerant Cm from the introduction pipe 232 into the pipe section 234. A partial section of the gas exhaust pipe 220 is cooled by the refrigerant Cm within the pipe section 234. The refrigerant Cm within the pipe section 234 is discharged from the discharge pipe 236. For example, the introduction pipe 232 and the discharge pipe 236 are provided with a heat exchanger that cools the refrigerant Cm by heat exchange. After the refrigerant Cm that has cooled the gas exhaust pipe 220 within the pipe section 234 passes through the discharge pipe 236, it is cooled by the heat exchanger and introduced into the pipe section 234 from the introduction pipe 232. Note that the refrigerant Cm may be any medium capable of cooling and solidifying a gaseous object (in this example, the monomer D), and may be, for example, water.

[0082] In this way, by cooling a partial section of the gas exhaust pipe 220 by the cooling mechanism 230, the gaseous object (in this example, the monomer D) contained in the gas G flowing through the gas exhaust pipe 220 solidifies by cooling and deposits on the inner wall surface of a partial section of the gas exhaust pipe 220. Note that the cooling mechanism 230 is not limited to being a tubular member through which the refrigerant Cm flows, and may be any mechanism capable of cooling a partial section of the gas exhaust pipe 220.

[0083] (Removing mechanism) The removing mechanism 240 is a mechanism for removing the solid object deposited in a partial section of the gas exhaust pipe 220.

[0084] The structure of the removal mechanism 240 may be arbitrary. In this embodiment, it is a tubular member that surrounds a partial section of the gas exhaust pipe 220. Further, the removal mechanism 240 of this embodiment shares its structure with the cooling mechanism 230, and the cooling mechanism 230 and the removal mechanism 240 are an integrated device. That is, the removal mechanism 240 of this embodiment has an introduction pipe 232, a pipe section 234, and a discharge pipe 236. In the removal mechanism 240, the heat medium Hm is introduced from the introduction pipe 232 into the pipe section 234. A partial section of the gas exhaust pipe 220 is heated by the heat medium Hm in the pipe section 234. The heat medium Hm in the pipe section 234 is discharged from the discharge pipe 236. For example, the introduction pipe 232 and the discharge pipe 236 are provided with a heat exchanger that heats the heat medium Hm by heat exchange. The heat medium Hm after heating the gas exhaust pipe 220 in the pipe section 234 is cooled by the heat exchanger via the discharge pipe 236 and introduced into the pipe section 234 from the introduction pipe 232. Note that the heat medium Hm may be any medium capable of heating and liquefying a solid object (in this example, the monomer D), and may be, for example, water.

[0085] In this way, by heating a partial section of the gas exhaust pipe 220 by the removal mechanism 240, the solid object (in this example, the monomer D) deposited on a partial section of the gas exhaust pipe 220 is liquefied and removed from the inside of the gas exhaust pipe 220. For example, in this embodiment, the gas exhaust pipe 220 extends vertically upward from the solution tank 210 toward a partial section (the section where the cooling mechanism 230 and the removal mechanism 240 are provided). Therefore, the liquefied object flows downward in the vertical direction inside the gas exhaust pipe 220 and returns to the inside of the solution tank 210.

[0086] Note that the removal mechanism 240 is not limited to being a tubular member through which the heat medium Hm flows, and may be any mechanism capable of removing a solid object from a partial section of the gas exhaust pipe 220. Further, the removal mechanism 240 is not limited to sharing its structure with the cooling mechanism 230 and may be a separate device. Also, the removal mechanism 240 is not an essential configuration. For example, even when the removal mechanism 240 is not provided, the solid object deposited on a partial section of the gas exhaust pipe 220 can be removed from the gas exhaust pipe 220 by an operator manually removing it.

[0087] (Control of Cooling Mechanism and Removal Mechanism) Next, a control method for the cooling mechanism 230 and the removal mechanism 240 in the present embodiment will be described. The cooling mechanism 230 and the removal mechanism 240 are controlled by the control unit 30.

[0088] The control unit 30 causes the seal gas Sg to be supplied to the solution tank 210 via the gas supply pipe 212. The gas G in the solution tank 210 is discharged from the gas exhaust pipe 220. The control unit 30 controls the cooling mechanism 230 to cool a partial section of the gas exhaust pipe 220. In the present embodiment, the control unit 30 causes the refrigerant Cm to be supplied to the pipe section 234, and the partial section of the gas exhaust pipe 220 is cooled by the refrigerant Cm. As a result, the gaseous object (monomer D in this example) contained in the gas G solidifies and precipitates in a partial section of the gas exhaust pipe 220.

[0089] When a predetermined amount or more of the solid object has precipitated in a partial section of the gas exhaust pipe 220, the control unit 30 stops the cooling by the cooling mechanism 230 and controls the removal mechanism 240 to remove the solid object from the gas exhaust pipe 220. In the present embodiment, when a predetermined amount or more of the solid object has precipitated, the control unit 30 stops the supply of the refrigerant Cm to the pipe section 234 and supplies the heat medium Hm to the pipe section 234. As a result, a partial section of the gas exhaust pipe 220 is heated, the precipitated solid object liquefies, and flows out and is removed from the gas exhaust pipe 220. In the present embodiment, when a predetermined amount or more of the solid object has precipitated, the control unit 30 also stops the operation of the solution tank 210 together with the stop of the cooling by the cooling mechanism 230. The stop of the operation of the solution tank 210 refers to the stop of the supply of the seal gas Sg to the solution tank 210, the stop of the supply of the target liquid L2 to the solution tank 210, and the stop of the discharge of the target liquid L2 from the solution tank 210.

[0090] Note that the criterion for determining whether a solid object has precipitated by a predetermined amount or more (the criterion for stopping the cooling mechanism 230 and starting the operation of the removal mechanism 240) may be arbitrary. However, in the present embodiment, the control unit 30 determines whether a solid object has precipitated by a predetermined amount or more based on the detection result of the pressure gauge 218. That is, for example, when the pressure value detected by the pressure gauge 218 is higher than a predetermined threshold value, the control unit 30 determines that a solid object has precipitated by a predetermined amount or more, stops the cooling by the cooling mechanism 230, and starts the control of the removal mechanism 240. On the other hand, when the pressure value detected by the pressure gauge 218 is equal to or lower than the predetermined threshold value, the control unit 30 determines that a solid object has not precipitated by a predetermined amount or more and continues the cooling by the cooling mechanism 230. Further, when the solid object is removed by the removal mechanism 240, the control unit 30 may stop the removal (heating) by the removal mechanism 240 and resume the cooling by the cooling mechanism 230. Note that the pressure threshold value here may be set arbitrarily.

[0091] (Effect of the First Embodiment) In this embodiment, the cooling mechanism 230 actively cools the inside of the gas exhaust pipe 220 to solidify the object. That is, if the object solidifies at an unexpected location inside the gas exhaust pipe 220, it becomes difficult to grasp the position of the solidified object and difficult to remove it. On the other hand, by solidifying the object at a predetermined location by the cooling mechanism 230, the position of the solidified object can be grasped, the solidified object can be appropriately removed, and blockage of the gas exhaust pipe 220 can be appropriately suppressed. Further, the storage system 200 according to this embodiment provides the cooling mechanism 230 in a partial section of the gas exhaust pipe 220 (for example, near the solution tank 210), flows the refrigerant Cm through the cooling mechanism 230, and after precipitating the gaseous object contained in the gas G in the solution tank 210 as a solid, it switches to the removal mechanism 240. The storage system 200 melts the object precipitated as a solid by flowing the heat medium Hm through the removal mechanism 240 and heating a partial section of the gas exhaust pipe 220, and stores it in the solution tank 210. Thereby, the storage system 200 can perform precipitation of the object in a partial section of the gas exhaust pipe 220, melt the precipitated solid object, and return the liquefied object to the solution tank 210. That is, precipitation of the object can be suppressed after a partial section of the gas exhaust pipe 220. Therefore, the liquid containing the object can be appropriately stored.

[0092] (Second Embodiment) In the first embodiment, when switching to the removal mechanism 240, the cooling mechanism 230 stopped the operation of the solution tank 210. The second embodiment is different from the first embodiment in that a plurality of cooling mechanisms 230 and removal mechanisms 240 are provided respectively. Configurations having the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0093] FIG. 5 is a schematic diagram for explaining the storage system according to the second embodiment.

[0094] The storage system 200A according to the second embodiment includes a solution tank 210, a gas exhaust pipe 220a, a gas exhaust pipe 220b, a cooling mechanism 230a, and a cooling mechanism 230b. Further, the storage system 200 has a removal mechanism 240a and a removal mechanism 240b.

[0095] (Gas exhaust pipe) The gas exhaust pipe 220a has a valve portion 222a. The valve portion 222a is, for example, an on-off valve and controls the flow of the gas G in the solution tank 210. In the present embodiment, when the valve portion 222b of the gas exhaust pipe 220b is in the closed state, the control unit 30 sets the valve portion 222a to the open state, and when the valve portion 222b is in the open state, the control unit 30 sets the valve portion 222a to the closed state. When the valve portion 222a is in the open state, the gas G in the solution tank 210 flows through the gas exhaust pipe 220a and is discharged to the outside.

[0096] The gas exhaust pipe 220b has a valve portion 222b. The valve portion 222b is, for example, an on-off valve and controls the flow of the gas G in the solution tank 210. In the present embodiment, when the valve portion 222a is in the closed state, the control unit 30 sets the valve portion 222b to the open state, and when the valve portion 222b is in the closed state, the control unit 30 sets the valve portion 222a to the open state. When the valve portion 222b is in the open state, the gas G in the solution tank 210 flows through the gas exhaust pipe 220b and is discharged to the outside.

[0097] (Cooling mechanism) The differences between the cooling mechanism 230a and the cooling mechanism 230b in the second embodiment and the cooling mechanism 230 in the first embodiment will be described.

[0098] The cooling mechanism 230a is provided in a partial section of the gas exhaust pipe 220a and cools the partial section of the gas exhaust pipe 220a. When the valve portion 222a is in the open state, the cooling mechanism 230a cools a partial section of the gas exhaust pipe 220a by supplying the refrigerant Cm under the control of the control unit 30, and deposits a solid object on the gas exhaust pipe 220a.

[0099] The cooling mechanism 230b is provided in a partial section of the gas exhaust pipe 220b and cools the partial section of the gas exhaust pipe 220b. When the valve portion 222b is in the open state, the cooling mechanism 230b cools a partial section of the gas exhaust pipe 220b by supplying the refrigerant Cm under the control of the control unit 30, and deposits a solid object on the gas exhaust pipe 220b.

[0100] (Removal mechanism) The differences between the removal mechanism 240a and the removal mechanism 240b in the second embodiment and the removal mechanism 240 in the first embodiment will be described.

[0101] The removal mechanism 240a is provided in a partial section of the gas exhaust pipe 220a to remove solid objects deposited in a partial section of the gas exhaust pipe 220a. When the valve part 222a is in the closed state, the removal mechanism 240a allows the heat medium Hm to flow inside the removal mechanism 240a to remove the solid objects deposited in a partial section of the gas exhaust pipe 220a. The removal mechanism 240b is provided in a partial section of the gas exhaust pipe 220b and, when the valve part 222b is in the closed state, allows the heat medium Hm to flow inside the removal mechanism 240b to remove the solid objects deposited in a partial section of the gas exhaust pipe 220b.

[0102] (Control of the cooling mechanism and the removal mechanism) In the second embodiment, the control unit 30 cools the gas exhaust pipe 220a by the cooling mechanism 230a while keeping the valve part 222a of the gas exhaust pipe 220a in the open state. Then, when a predetermined amount or more of solid objects are deposited in a partial section of the gas exhaust pipe 220a (for example, when the pressure of the pressure gauge 218 is higher than the threshold value), the control unit 30 switches the valve part 222a to the closed state and switches the valve part 222b to the open state. With the valve part 222a in the closed state, the control unit 30 stops the cooling by the cooling mechanism 230a and causes the removal mechanism 240a to remove the solid objects. Also, with the valve part 222b in the open state, the control unit 30 cools the gas exhaust pipe 220b by the cooling mechanism 230b.

[0103] After that, when a predetermined amount or more of solid objects are deposited in a partial section of the gas exhaust pipe 220b (for example, when the pressure of the pressure gauge 218 is higher than the threshold value), the control unit 30 switches the valve part 222b to the closed state and switches the valve part 222a to the open state. With the valve part 222b in the closed state, the control unit 30 stops the cooling by the cooling mechanism 230b and causes the removal mechanism 240b to remove the solid objects. Also, with the valve part 222a in the open state, the control unit 30 cools the gas exhaust pipe 220a by the cooling mechanism 230a.

[0104] In the above description, two gas exhaust pipes, cooling mechanisms, and removal mechanisms are provided. However, three or more gas exhaust pipes, cooling mechanisms, and removal mechanisms may be provided. That is, in the second embodiment, any number of gas exhaust pipes, cooling mechanisms, and removal mechanisms may be provided.

[0105] (Effect of the Second Embodiment) The storage system 200A includes a plurality of cooling mechanisms and a plurality of removal mechanisms. Therefore, while one is cooling or heating, the other can heat or cool. Accordingly, the plant can be operated without stopping the operation of the solution tank 210.

[0106] (Third Embodiment) In the first embodiment, the removal mechanism 240 removes the solid object deposited in a part of the gas exhaust pipe 220 by flowing the heat medium Hm therein. In the third embodiment, the removal mechanism 300 is different from the first embodiment in that it scrapes off the solid object deposited in a part of the gas exhaust pipe 220. The components having the same functions as those in the first embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted.

[0107] FIG. 6 is a schematic diagram for explaining the storage system according to the third embodiment. FIG. 7 is a schematic cross-sectional view of the storage system according to the third embodiment.

[0108] The storage system 200B includes a solution tank 210, a gas exhaust pipe 220, and a cooling mechanism 230. The storage system 200B also has a removal mechanism 300.

[0109] (Cooling Mechanism) The cooling mechanism 230 in the third embodiment has the same configuration as the cooling mechanism 230 in the first embodiment, so the description thereof is omitted. However, in the third embodiment, the cooling mechanism 230 and the removal mechanism 300 are separate devices, and the refrigerant Cm flows through the pipe portion 234 of the cooling mechanism 230, while the heat medium Hm does not flow.

[0110] Removing mechanism The removing mechanism 300 is a mechanism for scraping off solid objects deposited in a partial section of the gas exhaust pipe 220. That is, in the third embodiment, it is a mechanism for physically removing solid objects from the inner wall surface of the gas exhaust pipe 220. As shown in FIGS. 6 and 7, the removing mechanism 300 includes a support shaft 312 and a scraping portion 320.

[0111] The support shaft 312 is a shaft-shaped member disposed inside the gas exhaust pipe 220. The support shaft 312 is a shaft-shaped member rotatably inserted into the gas exhaust pipe 220. Note that the cross-sectional shape of the support shaft 312 may be any shape.

[0112] The scraping portion 320 is provided on the support shaft 312. In the present embodiment, the scraping portion 320 is provided at the tip of the support shaft 312. The scraping portion 320 rotates as the support shaft 312 rotates. By rotating, the scraping portion 320 scrapes off solid objects deposited on the inner wall of the gas exhaust pipe 220 while being in contact with the inner wall of the gas exhaust pipe 220.

[0113] The shape of the scraping portion 320 may be arbitrary, but in the present embodiment, it includes a support portion 322 and a scraping material 326. The support portion 322 is a rod-shaped member extending radially outward from the support shaft 312. Preferably, a plurality of support portions 322 are provided at equal intervals in the vertical direction. For example, in the present embodiment, six support portions 322 are provided. Note that the support portion 322 may have any structure and number. The support portion 322 may be, for example, a structure in which each support portion 322 is foldable or telescopic by a plurality of members. Here, the radial direction refers to the radial direction when the extending direction of the gas exhaust pipe 220 is taken as the axial direction.

[0114] The scraping member 326 is a member provided at the radially outer end of the support portion 322. The scraping member 326 extends along the axial direction and may be, for example, a member made of a fluororesin. The scraping member 326 is provided on the support portion 322 so as to contact the inner wall of the gas exhaust pipe 220. In the present embodiment, two scraping members 326 are provided. The scraping member 326 scrapes the solid object deposited on the inner wall of the gas exhaust pipe 220.

[0115] Note that the scraping member 326 is not limited to a member made of a fluororesin, and may be any member as long as it can scrape the solid object deposited on the inner wall of the gas exhaust pipe 220. Also, the number of the scraping members 326 may be arbitrary.

[0116] The control unit 30 drives the drive unit 310 (for example, a motor) provided in the removal mechanism 300 to rotate the support shaft 312. As a result, the scraping unit 320 rotates along with the rotation of the support shaft 312, and scrapes the solid object deposited in the gas exhaust pipe 220. When the removal mechanism 300 rotates in the gas exhaust pipe 220, the solid object in the gas exhaust pipe 220 is scraped and falls downward in the vertical direction. That is, the solid object scraped by the removal mechanism 300 falls again into the solution tank 210 and dissolves in the target liquid L2 stored in the solution tank 210.

[0117] (Modification of the Third Embodiment) FIG. 8 is a schematic cross-sectional view of a storage system according to a modification of the third embodiment. Note that the components having the same functions as those in the third embodiment are denoted by the same reference numerals and the description thereof is omitted.

[0118] (Removal Mechanism) In the above-described third embodiment, the removal mechanism 300 scrapes the solid object by rotating, but the method of scraping the solid object is not limited to rotation. For example, as shown in this modification, the removal mechanism 300 may scrape the solid object by moving in the axial direction.

[0119] Specifically, as shown in FIG. 8, the removal mechanism 300C according to this modification includes a drive unit 310C, a support shaft 312C, and a scraping unit 320C.

[0120] The drive unit 310C is, for example, a motor and controls the drive of the removal mechanism 300C. The drive unit 310C may be a handle, and an operator may operate it to control the drive of the removal mechanism 300C. Further, the drive unit 310C may have a motor mounted therein. In this case, the drive unit 310C may control the drive of the removal mechanism 300C automatically or the operator may operate the handle to control the drive of the removal mechanism 300C.

[0121] The support shaft 312C is a shaft-shaped member disposed within the gas exhaust pipe 220. The support shaft 312C is a member movable along the axial direction of the gas exhaust pipe 220. Note that the cross-sectional shape of the support shaft 312C may be any shape. Here, the axial direction refers to the direction in which the gas exhaust pipe 220 extends.

[0122] The scraping unit 320C is provided on the support shaft 312C. In the present embodiment, the scraping unit 320C is provided at the tip of the support shaft 312. The scraping unit 320C moves in the axial direction as it moves along the axial direction of the support shaft 312C. The scraping unit 320C moves in the axial direction while in contact with the inner wall of the gas exhaust pipe 220 to scrape the solid object deposited on the inner wall of the gas exhaust pipe 220.

[0123] The shape of the scraping unit 320C may be arbitrary, but in the present embodiment, it includes a support portion 322C and a scraping material 326C. The support portion 322C is a disk-shaped member extending radially outward from the support shaft 312C. The support portion 322C is provided such that the center of the support portion 322C coincides with the center of the support shaft 312C.

[0124] The scraping member 326C is a member provided at the tip of the support portion 322C. The scraping member 326C is a disk-shaped member extending in the radial direction. The scraping member 326C is provided such that its side surface contacts the inner wall of the gas exhaust pipe 220 and the surface (upper surface) on the support portion 322C side contacts the support portion 322C. The scraping member 326C scrapes the solid object deposited on the inner wall of the gas exhaust pipe 220.

[0125] Note that the scraping member 326C is a member made of a fluororesin in this embodiment, but it is not limited thereto, and any member may be used as long as it can scrape the solid object deposited on the inner wall of the gas exhaust pipe 220. Also, the shape of the scraping member 326C may be ring-shaped.

[0126] The control unit 30 controls the drive unit 310C, for example, to move the support shaft 312C in the axial direction. The scraping unit 320C scrapes the solid object by moving in the axial direction as the support shaft 312C moves with the scraping member 326C in contact with the inner wall of the gas exhaust pipe 220. Specifically, the scraping unit 320C reciprocates in the vertical direction within the gas exhaust pipe 220. In the vertical direction, the lower end of the scraping unit 320C descends to the lower end of the cooling mechanism 330 or below the lower end. Thereby, the solid object deposited in a part of the section of the gas exhaust pipe 220 can be scraped over that section. Also, in the vertical direction, the lower end of the scraping unit 320C rises above the side pipe 221 of the gas exhaust pipe 220. That is, the scraping unit 320C can move a longer distance in the axial direction than a part of the section of the gas exhaust pipe 220 as the support shaft 312C moves. By moving a longer distance in the axial direction than a part of the section of the gas exhaust pipe 220, the scraping unit 320C can scrape the solid object over a part of the section of the gas exhaust pipe 220 without preventing the flow of the gas flowing in the gas exhaust pipe 220.

[0127] (Effect of the Third Embodiment) The storage system 200B scrapes off the solid object deposited in a partial section of the gas exhaust pipe 220 by the rotational movement of the removal mechanism 300B. Since the scraping section 320 provided in the removal mechanism 300B is equal to or longer than a partial section of the gas exhaust pipe 220, the solid object deposited in a partial section of the gas exhaust pipe 220 can be scraped off over that section. Thereby, it is possible to suppress the deposition of the object in the section after a partial section of the gas exhaust pipe 220. Therefore, the liquid containing the object can be appropriately stored.

[0128] Further, the storage system 200C scrapes off the solid object deposited in a partial section of the gas exhaust pipe 220 by the axial movement of the removal mechanism 300C. Since the removal mechanism 300C can move longer in the axial direction than a partial section of the gas exhaust pipe 220, the solid object deposited over that section can be scraped off. Thereby, it is possible to suppress the deposition of the object in the section after a partial section of the gas exhaust pipe 220. Therefore, the liquid containing the object can be appropriately stored.

[0129] (Fourth Embodiment) In the third embodiment, when switching to the removal mechanism 300 or the removal mechanism 300C, the cooling mechanism 230 stopped the operation of the solution tank 210. The fourth embodiment is different from the third embodiment in that a plurality of cooling mechanisms 230 and removal mechanisms 300 are provided respectively. Configurations having the same functions as those in the third embodiment are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0130] FIG. 9 is a schematic diagram for explaining the storage system according to the fourth embodiment.

[0131] The storage system 200D according to the fourth embodiment includes a solution tank 210, a gas exhaust pipe 220a, a gas exhaust pipe 220b, a cooling mechanism 230a, and a cooling mechanism 230b. The storage system 200 also has a removal mechanism 300a and a removal mechanism 300b.

[0132] Since the gas exhaust pipes 220a and 220b in the fourth embodiment are the same as those in the second embodiment, the description thereof is omitted.

[0133] (Cooling mechanism) The differences between the cooling mechanisms 230a and 230b in the fourth embodiment and the cooling mechanism 230 in the third embodiment will be described.

[0134] The cooling mechanism 230a is provided in a partial section of the gas exhaust pipe 220a to cool the partial section of the gas exhaust pipe 220a. When the valve part 222a is in the open state, the cooling mechanism 230a cools a partial section of the gas exhaust pipe 220a by supplying the refrigerant Cm under the control of the control unit 30, and deposits a solid object on the gas exhaust pipe 220a.

[0135] The cooling mechanism 230b is provided in a partial section of the gas exhaust pipe 220b to cool the partial section of the gas exhaust pipe 220b. When the valve part 222b is in the open state, the cooling mechanism 230b cools a partial section of the gas exhaust pipe 220b by supplying the refrigerant Cm under the control of the control unit 30, and deposits a solid object on the gas exhaust pipe 220b.

[0136] (Removing mechanism) The differences between the removing mechanisms 300a and 300b in the fourth embodiment and the removing mechanism 300 in the third embodiment will be described.

[0137] The removing mechanism 300a is provided in a partial section of the gas exhaust pipe 220a to remove the solid object deposited on the partial section of the gas exhaust pipe 220a. When the valve part 222a is in the closed state, the removing mechanism 300a rotates to remove the solid object deposited in a partial section of the gas exhaust pipe 220a. The removing mechanism 300b is provided in a partial section of the gas exhaust pipe 220b and rotates to remove the solid object deposited in a partial section of the gas exhaust pipe 220b when the valve part 222b is in the closed state.

[0138] Note that the removal mechanism 300a and the removal mechanism 300b may be the removal mechanism 300C. In this case, the removal mechanism 300C scrapes off the solid object deposited in the gas exhaust pipe 220 by moving in the axial direction.

[0139] (Control of Cooling Mechanism and Removal Mechanism) In the fourth embodiment, the control unit 30 cools the gas exhaust pipe 220a by the cooling mechanism 230a while keeping the valve portion 222a of the gas exhaust pipe 220a in the open state. Then, when a solid object has deposited by a predetermined amount or more in a partial section of the gas exhaust pipe 220a (for example, when the pressure of the pressure gauge 218 is higher than the threshold value), the control unit 30 switches the valve portion 222a to the closed state and switches the valve portion 222b to the open state. The control unit 30 stops the cooling by the cooling mechanism 230a and removes the solid object by the removal mechanism 300a while the valve portion 222a is in the closed state. Further, the control unit 30 cools the gas exhaust pipe 220b by the cooling mechanism 230b while the valve portion 222b is in the open state.

[0140] Thereafter, when a solid object has deposited by a predetermined amount or more in a partial section of the gas exhaust pipe 220b (for example, when the pressure of the pressure gauge 218 is higher than the threshold value), the control unit 30 switches the valve portion 222b to the closed state and switches the valve portion 222a to the open state. The control unit 30 stops the cooling by the cooling mechanism 230b and removes the solid object by the removal mechanism 300b while the valve portion 222b is in the closed state. Further, the control unit 30 cools the gas exhaust pipe 220a by the cooling mechanism 230a while the valve portion 222a is in the open state.

[0141] In the above description, two gas exhaust pipes, cooling mechanisms, and removal mechanisms are provided, but three or more gas exhaust pipes, cooling mechanisms, and removal mechanisms may be provided. That is, in the fourth embodiment, any plurality of gas exhaust pipes, cooling mechanisms, and removal mechanisms may be provided.

[0142] (Effect of Fourth Embodiment) The storage system 200D is equipped with a plurality of cooling mechanisms and removal mechanisms respectively. Therefore, while one is performing cooling or scraping, the other can perform scraping or cooling. Accordingly, the plant can be stably operated without stopping the operation of the solution tank 210.

[0143] (Fifth Embodiment) In the above embodiments, the cooling mechanism 230 had a configuration having an introduction pipe 232, a pipe portion 234, and a derivation pipe 236, and flowing the refrigerant Cm in the pipe portion 234. However, in the fifth embodiment, it is different from the above embodiments in that it has a configuration having a shell 510 and a tube 520. FIG. 10 is a schematic cross-sectional view of the cooling mechanism according to the fifth embodiment.

[0144] (Cooling Mechanism) As shown in FIG. 10, the cooling mechanism 230c according to the fifth embodiment is provided in the middle of the pipeline of the gas exhaust pipe 220. In other words, the cooling mechanism 230c according to the fifth embodiment constitutes a part of the section of the gas exhaust pipe 220, and cools a part of the section of the gas exhaust pipe 220 by cooling the inside of the cooling mechanism 230c. The cooling mechanism 230c according to the fifth embodiment includes a shell 510 and a tube 520.

[0145] The shell 510 is a member with a hollow inside. Openings 512 and 514 that communicate the inside and the outside are formed in the shell 510. The shell 510 is connected to the portion of the gas exhaust pipe 220 on the side closer to the solution tank 210 than the shell 510 via the opening 512. The shell 510 is connected to the portion of the gas exhaust pipe 220 on the side opposite to the solution tank 210 (the side connected to the outside) than the shell 510 via the opening 514.

[0146] The gas G in the solution tank 210 is introduced into the shell 510 via the gas exhaust pipe 220 and the opening 512. The gas G in the shell 510 is discharged to the outside via the opening 514 and the gas exhaust pipe 220. That is, the shell 510 constitutes a part of the section of the gas exhaust pipe 220.

[0147] The tube 520 is a tubular member provided within the shell 510. An introduction pipe 516 and a discharge pipe 518 are connected to the tube 520. The refrigerant Cm is introduced into the tube 520 via the introduction pipe 516. The refrigerant Cm introduced into the tube 520 cools the gas G within the shell 510. The refrigerant Cm within the tube 520 is discharged into the discharge pipe 518. For example, a heat exchanger for cooling the refrigerant Cm by heat exchange is provided between the introduction pipe 516 and the discharge pipe 518, and the refrigerant Cm after cooling the interior of the shell 510 is cooled by the heat exchanger via the discharge pipe 518 and introduced from the discharge pipe 518 into the introduction pipe 516.

[0148] Thus, in the fifth embodiment, by cooling the shell 510 (a partial section of the gas exhaust pipe 220) with the refrigerant Cm within the tube 520, the gaseous object (in this example, the monomer D) contained in the gas G is solidified by cooling. The solidified object precipitates within the shell 510.

[0149] The removal mechanism 240c according to the present embodiment shares its structure with the cooling mechanism 230c, and the cooling mechanism 230c and the removal mechanism 240c are an integrated device. That is, the removal mechanism 240c of the present embodiment has the shell 510 and the tube 520. A heat medium Hm is introduced into the tube 520 of the removal mechanism 240c. The solid object that has precipitated within the shell 510 is heated by the heat medium Hm flowing through the tube 520 and liquefied. For example, a heat exchanger for heating the heat medium Hm by heat exchange is provided between the introduction pipe 516 and the discharge pipe 518, and the heat medium Hm after heating the interior of the shell 510 is heated by the heat exchanger via the discharge pipe 518 and introduced from the discharge pipe 518 into the introduction pipe 516.

[0150] Thus, by heating the interior of the shell 510 by the removal mechanism 240c, the solid object (in this example, the monomer D) that has precipitated within the shell 510 is liquefied and removed.

[0151] (Effect of the present disclosure) The storage system according to the first aspect of the present disclosure includes a solution tank 210 that stores a target liquid containing a liquid object, a gas exhaust pipe 220 connected to the solution tank 210 to discharge the gas G in the solution tank 210, and a cooling mechanism 230 that cools a part of the gas exhaust pipe 220 to deposit the gaseous object contained in the gas as a solid.

[0152] Thereby, in a part of the gas exhaust pipe provided with the cooling mechanism, the object can be solidified and the position of the solidified object can be grasped. That is, it is possible to suppress the precipitation of the solid object after a part of the gas exhaust pipe. Therefore, the liquid containing the object can be appropriately stored.

[0153] The storage system according to the second aspect of the present disclosure is the storage system according to the first aspect, wherein the cooling mechanism 230 is a tubular member surrounding a part of the gas exhaust pipe 220. In a part of the gas exhaust pipe provided with the cooling mechanism, the object can be solidified and the position of the solidified object can be grasped. That is, it is possible to suppress the precipitation of the solid object after a part of the gas exhaust pipe. Therefore, the liquid containing the object can be appropriately stored.

[0154] The storage system according to the third aspect of the present disclosure is the storage system according to the second aspect, wherein a refrigerant that cools a part of the gas exhaust pipe 220 by flowing a refrigerant Cm flows inside the cooling mechanism 230. Thereby, a solid object can be deposited by the cooling mechanism.

[0155] The storage system according to the fourth aspect of the present disclosure is the storage system according to any one of the first to third aspects, and has a removal mechanism 240 for removing the solid object deposited in a part of the gas exhaust pipe 220. Thereby, the solid object deposited by the cooling mechanism can be removed.

[0156] The storage system according to the fifth aspect of the present disclosure is the storage system according to the fourth aspect, wherein the removal mechanism 240 heats a part of the gas exhaust pipe 220 to melt and remove the solid object. Thereby, the solid object deposited by the cooling mechanism can be melted and removed.

[0157] The storage system according to the sixth aspect of the present disclosure is the storage system according to the fifth aspect, wherein the cooling mechanism 230 and the removal mechanism 240 are tubular members surrounding a part of the gas exhaust pipe 220. The cooling mechanism 230 cools a part of the gas exhaust pipe 220 by flowing the refrigerant Cm inside, and the removal mechanism 240 melts and removes the solid object by flowing the heat medium Hm inside. Thereby, the solid object deposited by the cooling mechanism can be melted and removed.

[0158] The storage system according to the seventh aspect of the present disclosure is the storage system according to the fourth aspect, wherein the removal mechanism 300 includes a support shaft 312 disposed in the gas exhaust pipe 220, and a scraping portion 320 provided on the support shaft 312 for scraping the solid object deposited in a part of the gas exhaust pipe 220. Therefore, the solid object deposited by the cooling mechanism can be scraped off.

[0159] The storage system according to the eighth aspect of the present disclosure is the storage system according to the seventh aspect, wherein the support shaft 312 is rotatable, and the scraping portion 320 rotates as the support shaft 312 rotates while being in contact with the inner wall of the gas exhaust pipe 220 to scrape the solid object. By doing so, since the scraping portion has a length at least equivalent to a part of the gas exhaust pipe, the deposited solid object can be scraped over that section.

[0160] The storage system according to the ninth aspect of the present disclosure is the storage system according to the seventh aspect, wherein the support shaft 312 is movable along the axial direction of the gas exhaust pipe 220, and the scraping portion 320 moves axially along with the movement of the support shaft 312 while being in contact with the inner wall of the gas exhaust pipe 220, thereby scraping the solid object. By doing so, the scraping portion can move longer than a partial section of the gas exhaust pipe in the axial direction, so that the deposited solid object can be scraped over that section.

[0161] The storage system according to the tenth aspect of the present disclosure is the storage system according to any one of the first to ninth aspects, wherein a gas supply pipe 212 for supplying a seal gas Sg that does not react with the object into the solution tank 210 is connected to the solution tank 210. Therefore, the seal gas can push out and discharge the components that react with the object from the solution tank, and it becomes possible to suppress the deterioration of the object.

[0162] The storage system according to the eleventh aspect of the present disclosure is the storage system according to any one of the first to tenth aspects, wherein the object has sublimability. Therefore, the cooling mechanism makes it easier to deposit the solid object.

[0163] As described above, the embodiments of the present invention have been described, but the embodiments are not limited by the contents of these embodiments. In addition, the above-described components include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate. Moreover, various omissions, substitutions, or changes of the components can be made without departing from the gist of the above-described embodiments.

Explanation of Reference Numerals

[0164] 1 Separation system 12 Dissolution section 13 Solid-liquid separation section 14 Solvent storage section 16 Reaction section 18 Separation section 30 Control section 82 Dissolution tank 86 Adjustment unit 90 Crystallization tank 100 Stirring unit 200, 200A~200D Storage system 210 Solution tank 212 Gas supply pipe 218 Pressure gauge 220, 220a, 220b Gas exhaust pipe 230, 230a, 230b Cooling mechanism 240, 300, 300C Removal mechanism 510 Shell 520 Tube Cm Refrigerant D, E, HD Monomer G Gas Hm Heat medium L2 Target liquid M Reaction solvent P Polyester solution Pd, L Dissolved solution Pm Polyester raw material R Residual substance

Claims

1. A solution tank for storing a target liquid containing a liquid target object, a gas exhaust pipe connected to the solution tank for discharging the gas in the solution tank, a cooling mechanism for cooling a partial section of the gas exhaust pipe to deposit the gaseous target object contained in the gas as a solid, comprising: a storage system.

2. The cooling mechanism is a tubular member surrounding a partial section of the gas exhaust pipe, The storage system according to Claim 1.

3. Inside the cooling mechanism, a refrigerant for cooling a partial section of the gas exhaust pipe flows, The storage system according to Claim 2.

4. having a removal mechanism for removing the solid target object deposited in a partial section of the gas exhaust pipe, The storage system according to Claim 1 or Claim 2.

5. The removal mechanism heats a partial section of the gas exhaust pipe to melt and remove the solid target object, The storage system according to Claim 4.

6. The cooling mechanism and the removal mechanism are tubular members surrounding a partial section of the gas exhaust pipe. The cooling mechanism cools a partial section of the gas exhaust pipe by allowing a refrigerant to flow inside, and the removal mechanism melts and removes the solid target object by allowing a heat medium to flow inside, The storage system according to Claim 5.

7. The removal mechanism includes a support shaft disposed in the gas exhaust pipe and a scraping portion provided on the support shaft for scraping the solid target object deposited in a partial section of the gas exhaust pipe, The storage system according to Claim 4.

8. The support shaft is rotatable, The scraping portion scrapes the solid target object by rotating along with the rotation of the support shaft while being in contact with the inner wall of the gas exhaust pipe, The storage system according to Claim 7.

9. The support shaft is movable along the axial direction of the gas exhaust pipe, The scraping portion scrapes the solid target object by moving in the axial direction along with the movement of the support shaft while being in contact with the inner wall of the gas exhaust pipe, The storage system according to Claim 7.

10. A gas supply pipe for supplying a sealing gas that does not react with the target object is connected to the solution tank, The storage system according to Claim 1 or Claim 2.

11. The target object has sublimability, The storage system according to Claim 1 or Claim 2.

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