Storage system

Abstract

The present invention appropriately stores a liquid containing an object. The present invention is provided with: a solution tank that stores a target liquid containing a liquid-form object; a gas exhaust pipe that is connected to the solution tank and discharges gas inside the solution tank; and a cooling mechanism that cools a partial section of the gas exhaust pipe and deposits, as a solid, a gaseous object contained in the gas.

Description

Storage System

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

[0002] There are known techniques for separating and extracting a target substance from a liquid containing the target substance. Patent Document 1 describes a technique for extracting a carboxylic acid by crystallizing the carboxylic acid by cooling a carboxylic acid-containing liquid.

[0003] WO 2007 / 088981

[0004] For example, a tank that stores a liquid containing a target substance may be provided with a pipe for discharging gas from the tank. Vaporized target substances may also flow through this pipe, and if the vaporized target substances are cooled by the influence of the external environment, the target substances may solidify and precipitate in the target substance pipe, potentially causing the pipe to become clogged. This may result in the liquid containing the target substances being unable to be properly stored.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a storage system that can appropriately store a liquid containing a target object.

[0006] In order to solve the above-mentioned problems and achieve the objectives, the storage system of the present disclosure comprises a solution tank for storing a target liquid containing a liquid target substance, a gas exhaust pipe connected to the solution tank for discharging gas from the solution tank, and a cooling mechanism for cooling a section of the gas exhaust pipe to precipitate the gaseous target substance contained in the gas as a solid.

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

[0008] FIG. 1 is a schematic diagram of a polyester recycling process in this embodiment. FIG. 2 is a schematic diagram of a separation system according to this embodiment. FIG. 3 is a schematic diagram illustrating a storage system according to the first embodiment. FIG. 4 is a cross-sectional schematic diagram of a cooling mechanism according to the first embodiment. FIG. 5 is a schematic diagram illustrating a storage system according to the second embodiment. FIG. 6 is a schematic diagram illustrating a storage system according to the third embodiment. FIG. 7 is a cross-sectional schematic diagram of a removal mechanism according to the third embodiment. FIG. 8 is a cross-sectional schematic diagram of a storage system according to a modified example of the third embodiment. FIG. 9 is a schematic diagram illustrating a storage system according to the fourth embodiment. FIG. 10 is a cross-sectional schematic diagram of a cooling mechanism according to the fifth embodiment.

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to these embodiments, and when there are multiple embodiments, the present invention also includes configurations in which the respective embodiments are combined.

[0010] (Recycling Process) FIG. 1 is a schematic diagram of a polyester recycling process according to this embodiment. In this embodiment, a polyester raw material Pm is depolymerized to form monomers, and the monomers are then repolymerized to recycle (regenerate) the polyester raw material Pm. Specifically, as shown in FIG. 1 , the polyester raw material Pm is flaked (step S100), the solution is mixed with a reaction solvent M for depolymerization (step S102), the depolymerized polyester monomers are purified (separated) to produce a carboxylic acid-derived monomer D and an alcohol component monomer E (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 is polymerized with the monomer E (step S108), thereby regenerating the polyester raw material Pm. In addition, in the recycling process employing the separation system 1 of this embodiment, the flaking step S100 may be omitted, or only the process of recovering monomers D and E shown in step S104 and monomer F shown in step S106 may be performed 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, but examples include waste products such as polyethylene terephthalate (PET), polyethylene butylene terephthalate (PEBT), polybutylene terephthalate (PBT), polycyclohexane dimethyl terephthalate (PCT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), and polycarbonate (PC). The polyester raw material Pm is not limited to those containing only polyester components, but also includes components other than polyester components. Examples of components other than polyester contained in the polyester raw material Pm include plastics other than polyester, such as polyethylene, polystyrene, polypropylene, and polyvinyl chloride, metals, dyes, pigments, and polymerization catalysts. Examples of polyester raw material Pm include clothing in which polyester and other components are knitted into fibers. Hereinafter, components other than polyester contained in the polyester raw material Pm are referred to as impurities.

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

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

[0014] (Alcohol Component Monomer) The alcohol component monomer E is an alcohol component monomer produced by a depolymerization reaction of the polyester. The monomer E may be, for example, a dihydroxy compound (dihydric alcohol), or more specifically, ethylene glycol (EG).

[0015] In the following, an example will be described in which the polyester is PET, the reaction solvent M is methanol, the monomer D is DMT, and the monomer E is EG.

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

[0017] Hereinafter, the Z direction is the vertical direction (up and down direction). The vertically upward direction of the Z direction is referred to as the Z1 direction, and the vertically downward direction of the Z direction is referred to as the Z2 direction. The horizontal direction is the direction perpendicular to the Z direction (vertical direction).

[0018] (Raw Material Storage Section) The raw material storage section 10 is a tank (hopper) into which the polyester raw material Pm is introduced and stored. In this embodiment, the raw material storage section 10 stores flaked polyester raw material Pm, but the shape and size of the polyester raw material Pm may be arbitrary. The raw material storage section 10 is connected to the dissolving section 12 via an inlet pipe 10a. The polyester raw material Pm in the raw material storage section 10 is supplied to the dissolving section 12 through the inlet pipe 10a. The inlet pipe 10a is provided with an adjustment section 10b that adjusts the amount of polyester raw material Pm supplied from the raw material storage section 10 to the dissolving section 12. The adjustment section 10b is, for example, an on-off valve. When in an open state, the adjustment section 10b allows the polyester raw material Pm in the raw material storage section 10 to be supplied to the dissolving section 12, and when in a closed state, it stops the supply of the polyester raw material Pm in the raw material storage section 10 to the dissolving section 12. However, the adjusting 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 dissolving section 12. Furthermore, the polyester raw material Pm may be supplied directly to the dissolving section 12 without passing through the raw material storage section 10, the introduction pipe 10a, and the adjusting section 10b.

[0019] (Dissolving section) The dissolving section 12 is a tank in which the dissolving liquid Pd is stored. The dissolving liquid Pd is a solution produced by mixing the polyester raw material Pm with 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 the polyester contained in the polyester raw material Pm, remain without dissolving in the monomer D. Therefore, it can be said that the dissolving liquid Pd contains a polyester solution P in which the polyester contained in the polyester raw material Pm is dissolved in the monomer D, and impurities contained in the polyester raw material Pm.

[0020] Monomer D and 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 undissolved in the monomer D, thereby producing a polyester solution P and a solution Pd containing impurities. By dissolving the polyester in the monomer D in this manner, the viscosity can be reduced and the fluidity can be improved, allowing the polyester to be easily introduced into the reaction section 16. Note that the polyester solution P is not limited to one in which the entire amount of polyester is dissolved in the monomer D; at least a portion of the polyester may be insoluble in the monomer D. Furthermore, if there is a component soluble in the monomer D among the components other than the polyester contained in the polyester raw material Pm, the polyester solution P may also contain that component dissolved in the monomer D.

[0021] The dissolving section 12 is connected to a first reaction section 16A (described later) via an inlet pipe 12a. The dissolving solution Pd in ​​the dissolving section 12 is supplied to the first reaction section 16A through the inlet pipe 12a. The inlet pipe 12a is also provided with a supply section 12a1. The supply section 12a1 is a mechanism for supplying the polyester solution P in the dissolving section 12 to the first reaction section 16A, and is a pump in this embodiment.

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

[0023] (Solvent reservoir) The solvent reservoir 14 is a tank into which the reaction solvent M is introduced and where the reaction solvent M is stored. The solvent reservoir 14 is connected to the reaction section 16 via an inlet pipe 14a. The reaction solvent M in the solvent reservoir 14 is supplied to the reaction section 16 through the inlet pipe 14a. More specifically, the inlet pipe 14a is provided with a heating and pressurizing section 14b that pressurizes and heats the reaction solvent M. The heating and pressurizing section 14b pressurizes and heats the reaction solvent M, thereby bringing the reaction solvent M into a supercritical state or a subcritical state (pressurized gas or pressurized liquid). The reaction section 16 is supplied with the reaction solvent M in a supercritical state or a subcritical state (pressurized gas or pressurized liquid).

[0024] (Reaction Section) The reaction section 16 is a container into which the solution Pd and the reaction solvent M are introduced to depolymerize the polyester in the solution Pd. 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 this embodiment, the first reaction section 16A can be said to be a portion of the reaction section 16 that is filled with a filler. The first reaction section 16A can be made of a known filler used in gas-liquid or liquid-liquid contactors, such as fillers similar to those used in contactors that bring heavy oil and water into contact to extract active ingredients. Specific examples of fillers include pipes made of stainless steel or the like, Raschig rings, Berl saddles, terrarettes, balls, and the like.

[0026] An inlet pipe 12a is connected to the first reaction unit 16A. More specifically, an inlet 16C, which is an opening of the inlet pipe 12a through which the dissolution liquid Pd from the dissolution unit 12 is introduced, is connected to the first reaction unit 16A. The inlet 16C is connected to a surface 16A1 on the first direction D1 side of the first reaction unit 16A. The inlet pipe 12a is connected to the surface 16A1 so that the inlet 16C opens toward a second direction D2, which is opposite to the first direction D1. In this embodiment, the inlet 16C opening toward the second direction D2 is connected to the surface 16A1 of the first reaction unit 16A, but this is not limiting. For example, the inlet 16C does not have to be directly connected to the first reaction unit 16A, and the inlet 16C opening toward the second direction D2 may be connected to a position closer to the first direction D1 side of the surface 16A1 of the first reaction unit 16A within the reaction unit 16.

[0027] An inlet pipe 14a is connected to the reaction section 16. More specifically, an inlet 16D, which is an opening of the inlet pipe 14a through which the reaction solvent M is introduced from the solvent reservoir 14, is connected to the reaction section 16. The inlet 16D is connected closer to the second direction D2 than the surface 16A2 on the second direction D2 side of the first reaction section 16A. The inlet pipe 14a is connected closer to the second direction D2 than the surface 16A2 so that the inlet 16D opens toward the first direction D1 or from the side toward the center. In this embodiment, the inlet 16D, which opens toward the first direction D1 or from the side toward the center, is connected closer to the second direction D2 than the surface 16A2 of the first reaction section 16A. However, this 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] In this embodiment, the inlet 16C through which the solution Pd is introduced opens in the second direction D2, and the inlet 16D through which the reaction solvent M is introduced opens in the first direction D1 or from the side toward the center. Therefore, the solution Pd and the reaction solvent M are introduced into the first reaction section 16A in directions facing each other.

[0029] The solution Pd introduced into the first reaction zone 16A from the inlet 16C moves in the second direction D2 on the surface of the filler in the first reaction zone 16A. Meanwhile, the reaction solvent M in a supercritical or subcritical state (pressurized gas or pressurized liquid) introduced from the inlet 16D moves in the first reaction zone 16A in the first direction D1. In the first reaction zone 16A, the reaction solvent M in a supercritical or subcritical state (pressurized gas or pressurized liquid) comes into contact with the solution Pd. The polyester in the solution Pd is depolymerized (reduced in molecular weight) by the reaction solvent M, and the depolymerized polyester is extracted into the reaction solvent M in a supercritical or subcritical state (pressurized gas or pressurized liquid). Hereinafter, the polyester depolymerized in the first reaction section 16A will be referred to as a first depolymerized polyester P1, and the mixture of the first depolymerized polyester P1 and the reaction solvent M (the reaction solvent M from which the first depolymerized polyester P1 has been extracted) will be referred to as a first solvent M1. The first solvent M1 containing the first depolymerized polyester P1 proceeds in the first direction D1 through the first reaction section 16A and is discharged to the first direction D1 side of the first reaction section 16A.

[0030] The first depolymerized polyester P1 includes monomers D and E produced by depolymerizing the polyester in the solution Pd, monomer D originally mixed in the solution Pd, and oligomers produced by depolymerizing the polyester. The oligomers referred to here refer to carboxylic acid-derived or alcohol-derived oligomers (carboxylic acid-derived or alcohol-derived oligomers with smaller molecular weights than polyester) that are not monomerized but are depolymerized from the polyester. Furthermore, 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 includes oligomers contained in the residual substance that have been depolymerized, as well as monomers D and E formed by depolymerizing the oligomers contained in the residual substance.

[0031] (Second Reaction Unit) The second reaction unit 16B is formed within the reaction unit 16, and is formed at a location where the first solvent M1 is discharged from the first reaction unit 16A. In this embodiment, the first solvent M1 is discharged in the first direction D1, and therefore the second reaction unit 16B can be said to be a space formed on the first direction D1 side of the first reaction unit 16A.

[0032] In the second reaction zone 16B, the first depolymerized polyester P1 contained in the first solvent M1 is further depolymerized (reduced in molecular weight) by the reaction solvent M contained in the first solvent M1. Hereinafter, the first depolymerized polyester P1 further depolymerized in the second reaction zone 16B will be referred to as the second depolymerized polyester P2, and the mixture of the second depolymerized polyester P2 and the reaction solvent M (the reaction solvent M in which the second depolymerized polyester P2 is dissolved) will be referred to as the second solvent M2. An outlet pipe 16a is connected to the second reaction zone 16B. More specifically, an outlet 16E, which is an opening of the outlet pipe 16a through which the second solvent M2 from the second reaction zone 16B is discharged, is connected to the second reaction zone 16B. The second solvent M2 containing the second depolymerized polyester P2 in the second reaction zone 16B is discharged from the outlet 16E through the outlet pipe 16a to the outside of the second reaction zone 16B.

[0033] The second depolymerized polyester P2 contains the monomers D and E in the first depolymerized polyester P1, the monomers D and E produced by depolymerizing the oligomers in the first depolymerized polyester P1, and the oligomers produced by depolymerizing the first depolymerized polyester P1.

[0034] A discharge pipe 16b is connected to the bottom of the reaction zone 16. More specifically, a discharge port 16F, which is an opening of the discharge pipe 16b through which non-extractable matter (described below) in the reaction zone 16 is discharged, is connected to the bottom of the reaction zone 16. The non-extractable matter includes impurities such as metal compounds that were not extracted into the reaction solvent M and residues of undecomposed polyester that were not extracted into the reaction solvent M. That is, the non-extractable matter at the bottom of the reaction zone 16 is discharged from the discharge port 16F through the discharge pipe 16b to the outside of the reaction zone 16. The non-extractable matter discharged from the discharge port 16F can be said to be components of the polyester solution P that were not led to the separation zone 18 as the second solvent M2 (reaction solvent M in which the second depolymerized polyester P2 is dissolved) but remained in the first reaction zone 16A and the second reaction zone 16B.

[0035] The reaction section 16 may also be provided with a heating section that heats the interior of the reaction section 16 and a pressurizing section that maintains the pressure inside the reaction section 16 at a predetermined value or higher. The temperature inside the reaction section 16 is preferably 250°C or higher and 400°C or lower, and more preferably 250°C or higher and 350°C or lower. The pressure inside the reaction section 16 is preferably 1 MPa or higher and 30 MPa or lower, and more preferably 6 MPa or higher and 25 MPa or lower. The pressurizing section and the heating section may be controlled by the control section 30.

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

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

[0038] The first separation section 18A is a separation column connected to the outlet pipe 16a. A second solvent M2 containing the second depolymerized polyester P2 is introduced into the first separation section 18A via the outlet pipe 16a. The first separation section 18A separates the second solvent M2 into a low-boiling component and a high-boiling component having a higher boiling point than the low-boiling component. For example, in the first separation section 18A, the second solvent M2 may be heated to a predetermined temperature, with the gaseous component being the low-boiling component and the liquid component being the high-boiling component. The first separation section 18A is connected to outlet pipes 18Aa and 18Ab. The low-boiling component is discharged from the outlet pipe 18Aa, and the high-boiling component is discharged from the outlet pipe 18Ab.

[0039] The second separation section 18B is a separation column connected to the first separation section 18A via an outlet pipe 18Aa. Low-boiling point components are introduced into the second separation section 18B via the outlet pipe 18Aa. The second separation section 18B separates the low-boiling point components into reaction solvent M and monomer E. Outlet pipes 18Ba and 18Bb are connected to the second separation section 18B. The reaction solvent M is discharged from the outlet pipe 18Ba, and the monomer E is discharged from the outlet pipe 18Bb. The outlet pipe 18Ba is connected to the second separation section 18B and the solvent reservoir 14. Therefore, the reaction solvent M discharged from the second separation section 18B is returned to the solvent reservoir 14 and reused for depolymerization of polyester.

[0040] The third separation section 18C is a separation column connected to the first separation section 18A via the outlet pipe 18Ab. High-boiling components are introduced into the third separation section 18C via the outlet pipe 18Ab. The third separation section 18C further separates the high-boiling components into high-boiling residual substances, low-boiling components containing the reaction solvent M and monomer E, and monomer D. The third separation section 18C is connected to the outlet pipes 18Ca, 18Cb, and 18Cc. The outlet pipe 18Ca is connected to the second separation section 18B. The low-boiling components separated in the third separation section 18C are discharged to the second separation section 18B via the outlet pipe 18Ca. Furthermore, the monomer D separated in the third separation section 18C is discharged from the outlet pipe 18Cb and introduced into the temporary storage section 70. The residual substances separated in the third separation section 18C are discharged from the outlet pipe 18Cc.

[0041] An inlet pipe 18Cd is connected to the third separation section 18C. The inlet pipe 18Cd is also connected to the dissolving section 12 and introduces the monomer D discharged from the third separation section 18C into the dissolving section 12. In the example shown in FIG. 2 , the inlet pipe 18Cd branches off from the outlet pipe 18Cb. The inlet pipe 18Cd is provided with an adjustment section 18Ce that adjusts the amount of monomer D supplied from the third separation section 18C to the dissolving section 12. The adjustment section 18Ce is, for example, an on-off valve that, when open, allows the monomer D to be supplied to the dissolving section 12 and, when closed, stops the supply of the monomer D to the dissolving section 12. However, the adjustment section 18Ce is not limited to an on-off valve and may be any mechanism capable of adjusting the supply of monomer D to the dissolving section 12. In this embodiment, the adjustment section 18Ce is provided at the point where the inlet pipe 18Cd branches off from the outlet pipe 18Cb, but the adjustment section 18Ce may be provided at any position. Furthermore, the inlet pipe 18Cd does not have to be connected to the outlet pipe 18Cb, and may be directly connected to the third separation section 18 C. Alternatively, for example, the outlet pipe 18Cb may be provided with a reservoir (tank) for storing the monomer D, and the inlet pipe 18Cd may be connected to the reservoir.

[0042] An inlet pipe 18Cf is connected to the third separation section 18C. The inlet pipe 18Cf is also connected to the dissolving section 12 and introduces the residual material R discharged from the third separation section 18C into the dissolving section 12. In the example shown in FIG. 2, the inlet pipe 18Cf branches off from the outlet pipe 18Cc. The inlet pipe 18Cf is provided with an adjustment section 18Cg that adjusts the amount of residual material R supplied from the third separation section 18C to the dissolving section 12. The adjustment section 18Cg is, for example, an on-off valve. When open, the adjustment section 18Cg allows the residual material R to be supplied to the dissolving section 12, and when closed, the adjustment section 18Cg stops the supply of the residual material R to the dissolving section 12. However, the adjustment section 18Cg is not limited to an on-off valve and may be any mechanism capable of adjusting the supply of the residual material R to the dissolving section 12. In this embodiment, the adjustment section 18Cg is provided at the point where the inlet pipe 18Cf branches off from the outlet pipe 18Cc, but the adjustment section 18Cg may be provided at any location. Furthermore, the inlet pipe 18Cf does not have to be connected to the outlet pipe 18Cc, and may be directly connected to the third separation section 18C.

[0043] For example, the discharge pipe 18Cc may be provided with a reservoir (tank) for storing the residual substance R, and the introduction pipe 18Cf may be connected to the reservoir. The introduction pipe 18Cf may also be provided with a filter that allows oligomers in the residual substance R to pass through while collecting foreign matter in the residual substance R.

[0044] (Temporary Storage Section) The temporary storage section 70 is, for example, a tank, and temporarily stores the monomer D supplied from the third separation section 18C. The temporary storage section 70 is connected to the third separation section 18C via an outlet pipe 18Cb. The temporary storage section 70 is connected to the dissolution tank 82 via an outlet pipe 72. The temporary storage section 70 supplies the temporarily stored monomer D to the dissolution tank 82.

[0045] (Dissolution Tank) The dissolution tank 82 is a tank that stores a solution L in which the monomer D is dissolved. The dissolution tank 82 is connected to the temporary storage section 70 via the outlet pipe 72. The monomer D containing impurities separated in the third separation section 18C is introduced from the temporary storage section 70 into the dissolution tank 82. A solvent that dissolves the monomer D is also introduced into the dissolution tank 82. As a result, the monomer D is dissolved in the solvent in the dissolution tank 82 and stored as a solution L. Note that any liquid may be used as the solvent, but methanol is used in this embodiment.

[0046] The dissolution tank 82 is connected to an adjustment unit 86 and a crystallization tank 90 via an inlet pipe 84. The solution L stored in the dissolution tank 82 is introduced into the crystallization tank 90 via the inlet pipe 84 and the adjustment unit 86. The dissolution tank 82 is located in the Z1 direction (vertically above) the crystallization tank 90, which will be described later. However, the positional relationship between the dissolution tank 82 and the crystallization tank 90 in the Z direction 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 dissolution tank 82 with the opening of the crystallization tank 90. ​​The solution L in the dissolution tank 82 flows into the crystallization tank 90 through the inlet pipe 84 and the adjustment unit 86.

[0048] (Adjustment Unit) The adjustment unit 86 is a device that reduces the pressure of the solution 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 solution L introduced from the dissolution tank 82 via the inlet pipe 84, and introduces the solution L in a reduced pressure state into the crystallization tank 90.

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

[0050] The solution L introduced into the adjusting section 86 is introduced into the crystallization tank 90 in a state where the pressure of the solution L has been reduced by the adjusting section 86. Since the temperature of the reduced-pressure solution L is reduced, the monomer HD to be separated is crystallized from the reduced-pressure solution L.

[0051] In this embodiment, the adjustment unit 86 is directly connected to the crystallization tank 90, but this 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 solution L depressurized by the adjustment unit 86 is introduced and in which the object to be separated (monomer HD in this case) is crystallized from the solution L. The solution L depressurized by the adjustment unit 86 is introduced into the crystallization tank 90. ​​In this way, the depressurized solution L is introduced into the crystallization tank 90 and the solution L is stored in a depressurized state. In other words, the crystallization tank 90 can be said to be a flash-type crystallization tank in which the internal pressure is reduced below the external pressure.

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

[0054] A baffle 110 is provided inside the crystallization tank 90 to rectify the flow of the solution L in the crystallization tank 90. ​​The shape, mounting position, and number of the baffle 110 are arbitrary, but in this embodiment, the baffle 110 is provided on the inner wall surface of the crystallization tank 90, and more specifically, is a plate-shaped 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 does not have to be provided in the crystallization tank 90.

[0055] (Agitation Unit) The agitation unit 100 is provided in the crystallization tank 90 and rotates when a drive unit (e.g., a motor) is driven, thereby agitating the inside of the crystallization tank 90. ​​In this embodiment, the agitation blade is located on the Z2 side of the adjustment unit 86. The agitation blade is also located on the Z1 side of the bottom surface of the crystallization tank 90, facing the bottom surface (i.e., overlapping the bottom surface as viewed from the Z direction). The agitation unit 100 is preferably provided at the center of the crystallization tank 90 as viewed from the Z direction. That is, it is preferable that the central axis of the agitation unit 100 and the central axis of the crystallization tank 90 coincide with each other.

[0056] (Solid-Liquid Separation Section) The solid-liquid separation section 120 is connected to the crystallization tank 90 via a discharge pipe 121. The slurry S (solution L in which the monomer HD has been crystallized) produced in the crystallization tank 90 is introduced into the solid-liquid separation section 120 from the crystallization tank 90 via the discharge pipe 121. The solid-liquid separation section 120 separates the introduced slurry S into solid and liquid components. The solid-liquid separation section 120 separates the slurry S into solid components to be separated and liquid components. In this embodiment, the solid-liquid separation section 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 discharged from a discharge pipe 123 connected to the solid-liquid separation section 120 and treated. The solid-liquid separation unit 120 may be, for example, a centrifuge, which separates the separation target from the solution L by centrifuging, stirring the interior of the solid-liquid separation unit 120 around a predetermined axis and moving the separation target radially outward from the rotating shaft. The solid-liquid separation unit 120 is not limited to centrifugal separation as long as it can separate the separation target from the solution L. For example, the solid-liquid separation unit 120 may separate the separation target from the solution L using a filter.

[0057] (Melting Tank) The melting tank 130 is connected to the solid-liquid separation section 120 via an outlet pipe 122. The melting tank 130 is also connected to a temporary melt storage tank 140 via a supply pipe 132. The melting tank 130 melts (melts) the highly pure monomer HD obtained through solid-liquid separation from the slurry S. The melting tank 130 melts the monomer HD to form a liquid, and supplies the liquid to the temporary melt storage tank 140 via the supply pipe 132.

[0058] (Temporary melt storage tank) The temporary melt storage tank 140 is connected to the hydrolysis separation reaction section 150 via an outlet pipe 142. The temporary melt storage tank 140 is a tank that temporarily stores the monomer HD that has been melt-treated in the melting tank 130. The temporary melt 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 undergoes a crystallization process and a drying process (not shown) and is stored in a hopper.

[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 polyester raw material Pm supplied from the raw material storage unit 10 to the dissolution unit 12. Furthermore, if the solid-liquid separation unit 13 is equipped with a drive unit, the control unit 30 controls the operation of the solid-liquid separation unit 13. The control unit 30 controls the supply unit 12a1 to control the amount of solution Pd supplied from the dissolution unit 12 to the reaction unit 16. The control unit 30 controls the heating and pressurization unit 14b to bring the reaction solvent M to a supercritical state or subcritical state (pressurized gas or pressurized liquid) and controls the amount of reaction solvent M in the supercritical state or subcritical state (pressurized gas or pressurized liquid) supplied to the reaction unit 16. The control unit 30 controls the adjustment unit 18Ce to control the amount of monomer D supplied to the dissolution unit 12. The control unit 30 controls the adjustment unit 18Cg to control the amount of residual material R supplied to the dissolution unit 12. The control unit 30 adjusts the adjustment unit 86 to reduce the pressure of the solution L while controlling the flow rate of the solution L into the crystallization tank 90. ​​The control unit 30 controls the rotation of the stirring unit 100. The control unit 30 controls the operation of the storage system 200, which will be described later.

[0061] In this embodiment, the control unit 30 is a computer, and includes a processor including an arithmetic circuit such as a CPU (Central Processing Unit), and a storage unit that stores various information such as the contents of calculations performed by the processor and programs. The control unit 30 executes control of the separation system 1 by reading out programs from the storage unit.

[0062] However, the separation system 1 is not limited to being automatically controlled by the control unit 30, and for example, at least a part of the processing may be controlled by the operation of an operator.

[0063] (Operation of 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 solution Pd. The control unit 30 controls the supply unit 12a1 to introduce the solution 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 at 250° C. or higher and 400° C. or lower, and more preferably at 250° C. or higher and 350° C. or lower. The control unit 30 preferably sets the reaction solvent M at 1 MPa or higher and 30 MPa or lower, and more preferably at 6 MPa or higher and 25 MPa or lower.

[0065] In this manner, by supplying the solution Pd and the reaction solvent M to the reaction section 16, the polyester contained in the solution Pd is depolymerized in the first reaction section 16A to produce a first depolymerized polyester P1. Then, in the second reaction section 16B, the first depolymerized polyester P1 is further depolymerized to produce a second solvent M2, which is a mixture of a second depolymerized polyester P2 and the reaction solvent M. The second solvent M2 is separated into the reaction solvent M, monomer D, monomer E, and residual substances in the first separation section 18A, the second separation section 18B, and the third separation section 18C.

[0066] The control unit 30 controls the adjustment unit 86 to supply the solution L to the adjustment unit 86, depressurize the solution L using the adjustment unit 86, and introduce the depressurized solution L into the crystallization tank 90. ​​Since the solution L introduced into the crystallization tank 90 has been depressurized, the target monomer HD is crystallized from the solution L in the crystallization tank 90.

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

[0068] (Storage System) FIG. 3 is a schematic diagram illustrating the storage system according to the first embodiment. FIG. 4 is a cross-sectional schematic diagram 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, and has a solution tank 210 for storing the target liquid. Target Here, the target refers to a substance that will be treated in a subsequent stage, for example, a substance that will be separated from other substances in a subsequent stage. The target may be any substance that will be treated in a subsequent stage, for example, a substance that has sublimation properties. In this embodiment, the target is monomer D.

[0069] In this embodiment, the storage system 200 is provided in the separation system 1 and stores a target liquid containing liquid monomer D. More specifically, the storage system 200 is provided in a location in the separation system 1 where the target liquid containing liquid monomer D is stored. That is, in this embodiment, the storage system 200 is provided in at least one of the dissolving section 12, which stores the solution Pd, the temporary storage section 70, which stores the monomer D separated in the third separation section 18C, and the temporary melt storage tank 140, which stores the monomer D (monomer HD) whose purity has been increased by crystallization. In other words, at least one of the dissolving section 12, the temporary storage section 70, and the temporary melt storage tank 140 can be considered to be the solution tank 210 of the storage system 200. It is preferable that the storage system 200 be provided in all of the dissolving section 12, the temporary storage section 70, and the temporary melt storage tank 140. However, the storage system 200 is not limited to being provided in the separation system 1 for storing a target liquid containing the monomer D, and may be provided to store a target liquid containing a liquid target substance of any component. For example, the storage system 200 may be provided in a tank that stores a target liquid containing an organic substance or an inorganic substance (e.g., iodine) other than the monomer D.

[0070] The storage system 200 according to this embodiment will be specifically described below.

[0071] 3, the storage system 200 includes a solution tank 210 (in this embodiment, the dissolving section 12, the temporary storage section 70, and the temporary melt storage tank 140), a gas exhaust pipe 220, and a cooling mechanism 230. The storage system 200 also includes a removal mechanism 240.

[0072] (Solution Tank) The solution tank 210 is a tank that stores a target liquid L2 containing a liquid target substance. A target liquid inlet pipe 214 and a target liquid outlet pipe 216 are connected to the solution tank 210. The target liquid L2 containing a liquid target substance is introduced into the solution tank 210 through the target liquid inlet pipe 214, and the target liquid L2 is stored in the solution tank 210. The target liquid L2 stored in the solution tank 210 is discharged through the target liquid outlet pipe 216. In this embodiment, the target liquid inlet pipe 214 is connected to the side of the solution tank 210, but the connection point may be arbitrary, and may be connected to the top surface of the solution tank 210, for example. The target liquid outlet pipe 216 is connected to the bottom surface of the solution tank 210, but the connection point may be arbitrary, and may be connected to the side surface of the solution tank 210, for example.

[0073] For example, when the solution tank 210 is the dissolving section 12, the inlet pipe 10a is the target liquid inlet pipe 214, the inlet pipe 12a is the target liquid outlet pipe 216, and a solution Pd, which is a liquid target substance dissolved in monomer D and polyester raw material Pm, is supplied to and stored in the solution tank 210. Alternatively, when the solution tank 210 is the temporary storage section 70, the outlet pipe 18Cb is the target liquid inlet pipe 214, the outlet pipe 72 is the target liquid outlet pipe 216, and a liquid target substance, monomer D, is supplied to and stored in the solution tank 210. Alternatively, when the solution tank 210 is the temporary melt storage tank 140, the supply pipe 132 is the target liquid inlet pipe 214, the outlet pipe 142 is the target liquid outlet pipe 216, and a liquid target substance, monomer HD, is supplied to and stored in the solution tank 210.

[0074] The solution tank 210 is also provided with a pressure gauge 218. The pressure gauge 218 is a sensor that is provided in the solution tank 210 and measures the pressure inside the solution tank 210. In this embodiment, the pressure gauge 218 is provided on the upper surface of the solution tank 210, but 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 that supplies a 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 any position. The seal gas Sg is continuously supplied from the gas supply pipe 212 into the solution tank 210. The seal gas Sg is a gas that does not react with the target substance (monomer D), and may be, for example, nitrogen gas or a rare 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 and exhausts gas from the solution tank 210. In this embodiment, the gas exhaust pipe 220 is connected to the top surface of the solution tank 210, but the connection position is not limited to this and may be any position. 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 exhausted 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] (Gas Exhaust) In this manner, 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 exhausted 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 exhausted from the gas exhaust pipe 220. Since the target substance (e.g., monomer D) stored in the solution tank 210 may react with oxygen and be altered, exhausting the oxygen contained in the air with the seal gas Sg in this manner can suppress the alteration of the target substance. Note that the seal gas Sg supplied to the solution tank 210 is also exhausted from the gas exhaust pipe 220. Hereinafter, the gas exhausted from the gas exhaust pipe 220 will be referred to as gas G as appropriate.

[0078] Here, at least a portion of the target substance (e.g., monomer D) in the solution tank 210 may vaporize. The vaporized target substance is contained in gas G and discharged from the gas exhaust pipe 220. However, because the target substance has a high sublimation tendency, if a low-temperature section occurs in the gas exhaust pipe 220 due to, for example, the external environment, the vaporized target substance in that section may solidify, potentially clogging the gas exhaust pipe 220. This may result in an inability to properly store the liquid containing the target substance. In contrast, in this embodiment, the cooling mechanism 230 actively cools the gas exhaust pipe 220 to solidify the target substance. In other words, if the target substance solidifies in an unexpected location in the gas exhaust pipe 220, it becomes difficult to determine the location of the solidified target substance and to remove it. In contrast, by solidifying the target substance at a predetermined location using the cooling mechanism 230, the location of the solidified target substance can be determined, the solidified target substance can be properly removed, and clogging of the gas exhaust pipe 220 can be appropriately suppressed.

[0079] (Cooling Mechanism) The cooling mechanism 230 cools a partial section of the gas exhaust pipe 220 to precipitate gaseous substances contained in the gas as a solid. The cooling mechanism 230 is provided in a partial section of the gas exhaust pipe 220. The partial section of the gas exhaust pipe 220 where the cooling mechanism 230 is provided may be located at any position within the entire section of the gas exhaust pipe 220. However, for example, the partial section is preferably located closer to the solution bath 210 than the midpoint 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 bath 210. Furthermore, when a side pipe 221 is connected to the gas exhaust pipe 220, the partial section is preferably located between the end of the gas exhaust pipe 220 connected to the solution bath 210 and the connection point of the side pipe 221.

[0080] The cooling mechanism 230 may have any structure, but in this embodiment, it is a tubular member that surrounds a partial section of the gas exhaust pipe 220. More specifically, as shown in Figures 3 and 4, the cooling mechanism 230 has an inlet pipe 232, a pipe section 234, and an outlet pipe 236.

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

[0082] In this way, by cooling a partial section of the gas exhaust pipe 220 using the cooling mechanism 230, the gaseous object (monomer D in this example) contained in the gas G flowing through the gas exhaust pipe 220 is solidified by cooling and precipitates on the inner wall surface of the 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 that can cool a partial section of the gas exhaust pipe 220.

[0083] (Removal Mechanism) The removal mechanism 240 is a mechanism that removes solid objects that have precipitated in a section of the gas exhaust pipe 220 .

[0084] The structure of the removal mechanism 240 may be arbitrary, but in this embodiment, it is a tubular member that surrounds a partial section of the gas exhaust pipe 220. Furthermore, 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 inlet pipe 232, a pipe section 234, and an outlet pipe 236. In the removal mechanism 240, the heat medium Hm is introduced from the inlet pipe 232 to 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 outlet pipe 236. For example, the inlet pipe 232 and the outlet pipe 236 are provided with a heat exchanger that heats the heat medium Hm by heat exchange, and the heat medium Hm that has heated the gas exhaust pipe 220 in the pipe section 234 is cooled by the heat exchanger via the outlet pipe 236 and introduced from the inlet pipe 232 into the pipe section 234. The heat medium Hm may be any medium that can heat and liquefy a solid object (monomer D in this example), and may be, for example, water.

[0085] In this way, by heating a portion of the gas exhaust pipe 220 using the removal mechanism 240, the solid object (monomer D in this example) precipitated in the portion of the gas exhaust pipe 220 is liquefied and removed from the gas exhaust pipe 220. For example, in this embodiment, the gas exhaust pipe 220 extends vertically upward from the solution bath 210 toward the portion of the gas exhaust pipe 220 (the portion where the cooling mechanism 230 and the removal mechanism 240 are provided). Therefore, the liquefied object flows vertically downward through the gas exhaust pipe 220 and is returned to the solution bath 210.

[0086] 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 solid objects from a partial section of the gas exhaust pipe 220. The removal mechanism 240 is not limited to sharing a structure with the cooling mechanism 230, and may be a separate device. The removal mechanism 240 is not an essential component. For example, even if the removal mechanism 240 is not provided, the solid objects deposited in a partial section of the gas exhaust pipe 220 can be removed from the gas exhaust pipe 220 by an operator manually removing the solid objects.

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

[0088] The control unit 30 supplies a seal gas Sg to the solution tank 210 via the gas supply pipe 212. The gas G in the solution tank 210 is exhausted 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 this embodiment, the control unit 30 supplies a refrigerant Cm to the pipe section 234, and cools the partial section of the gas exhaust pipe 220 with the refrigerant Cm. As a result, the gaseous target substance (monomer D in this example) contained in the gas G solidifies and precipitates in the partial section of the gas exhaust pipe 220.

[0089] When a predetermined amount or more of the solid object has precipitated in a portion of the gas exhaust pipe 220, the control unit 30 stops cooling by the cooling mechanism 230 and controls the removal mechanism 240 to remove the solid object from the gas exhaust pipe 220. In this 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 portion 234 and supplies the heat medium Hm to the pipe portion 234. This heats the portion of the gas exhaust pipe 220, liquefying the precipitated solid object and causing it to flow out of the gas exhaust pipe 220 and be removed. Note that in this embodiment, when a predetermined amount or more of the solid object has precipitated, the control unit 30 stops cooling by the cooling mechanism 230 and also stops operation of the solution bath 210. Stopping the operation of the solution tank 210 means stopping the supply of the seal gas Sg to the solution tank 210, stopping the supply of the subject liquid L2 to the solution tank 210, and stopping the discharge of the subject liquid L2 from the solution tank 210.

[0090] The criteria for determining whether a predetermined amount of solid objects has been deposited (criteria for stopping the cooling mechanism 230 and starting the operation of the removal mechanism 240) may be arbitrary. In this embodiment, the control unit 30 determines whether a predetermined amount of solid objects has been deposited based on the detection results of the pressure gauge 218. That is, for example, if the pressure value detected by the pressure gauge 218 is higher than a predetermined threshold, the control unit 30 determines that a predetermined amount of solid objects has been deposited, stops cooling by the cooling mechanism 230, and starts control of the removal mechanism 240. On the other hand, if the pressure value detected by the pressure gauge 218 is equal to or lower than the predetermined threshold, the control unit 30 determines that a predetermined amount of solid objects has not been deposited, and continues cooling by the cooling mechanism 230. Furthermore, once the solid objects have been removed by the removal mechanism 240, the control unit 30 may stop removal (heating) by the removal mechanism 240 and resume cooling by the cooling mechanism 230. The pressure threshold here may be set arbitrarily.

[0091] Effect of First Embodiment In this embodiment, the cooling mechanism 230 actively cools the inside of the gas exhaust pipe 220 to solidify the target object. In other words, if the target object solidifies in an unexpected location in the gas exhaust pipe 220, it becomes difficult to determine the location of the solidified target object and to remove it. In contrast, by solidifying the target object in a predetermined location using the cooling mechanism 230, the location of the solidified target object can be determined, the solidified target object can be appropriately removed, and blockage of the gas exhaust pipe 220 can be appropriately prevented. Furthermore, the storage system 200 according to this embodiment is provided with the cooling mechanism 230 in a section of the gas exhaust pipe 220 (e.g., near the solution bath 210), and the refrigerant Cm flows through the cooling mechanism 230. The gaseous target object contained in the gas G in the solution bath 210 is precipitated as a solid, and then the removal mechanism 240 is switched on. In the storage system 200, the heat medium Hm flows in the removal mechanism 240 to heat a portion of the gas exhaust pipe 220, thereby melting the target material precipitated as a solid and storing it in the solution tank 210. In this way, the storage system 200 precipitates the target material in a portion of the gas exhaust pipe 220 and melts the precipitated solid target material, so that the liquefied target material can be returned to the solution tank 210. In other words, it is possible to suppress precipitation of the target material in the portion of the gas exhaust pipe 220 and beyond. Therefore, it is possible to appropriately store the liquid containing the target material.

[0092] Second Embodiment In the first embodiment, the cooling mechanism 230 stops the operation of the solution tank 210 when switching to the removal mechanism 240. The second embodiment differs from the first embodiment in that a plurality of cooling mechanisms 230 and a plurality of removal mechanisms 240 are provided. Components having the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0093] FIG. 5 is a schematic diagram illustrating a 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. The storage system 200 also includes a removal mechanism 240a and a removal mechanism 240b.

[0095] (Gas Exhaust Pipe) The gas exhaust pipe 220a has a valve 222a. The valve 222a is, for example, an on-off valve, and controls the flow of gas G inside the solution bath 210. In this embodiment, the control unit 30 opens the valve 222a when the valve 222b of the gas exhaust pipe 220b is closed, and closes the valve 222a when the valve 222b is open. When the valve 222a is open, the gas G inside the solution bath 210 flows through the gas exhaust pipe 220a and is exhausted to the outside.

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

[0097] (Cooling Mechanism) 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 unit 222a is in an open state, the cooling mechanism 230a is supplied with a refrigerant Cm under the control of the control unit 30, thereby cooling the partial section of the gas exhaust pipe 220a and causing solid objects to precipitate in 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 unit 222b is in an open state, the cooling mechanism 230b is supplied with a refrigerant Cm under the control of the control unit 30, thereby cooling the partial section of the gas exhaust pipe 220b and causing solid objects to precipitate in the gas exhaust pipe 220b.

[0100] (Removal Mechanism) Differences between the removal mechanisms 240a and 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 and removes solid objects that have precipitated in that partial section of the gas exhaust pipe 220a. The removal mechanism 240a flows a heat medium Hm inside the removal mechanism 240a when the valve unit 222a is closed, thereby removing solid objects that have precipitated in that 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 flows a heat medium Hm inside the removal mechanism 240b when the valve unit 222b is closed, thereby removing solid objects that have precipitated in that partial section of the gas exhaust pipe 220b.

[0102] (Control of Cooling Mechanism and Removal Mechanism) In the second embodiment, the control unit 30 controls the cooling mechanism 230a to cool the gas exhaust pipe 220a while keeping the valve 222a of the gas exhaust pipe 220a open. Then, when a predetermined amount or more of solid objects have precipitated in a section of the gas exhaust pipe 220a (for example, when the pressure of the pressure gauge 218 is higher than the threshold), the control unit 30 switches the valve 222a to a closed state and the valve 222b to an open state. With the valve 222a closed, the control unit 30 stops cooling by the cooling mechanism 230a and controls the removal mechanism 240a to remove the solid objects. Furthermore, with the valve 222b open, the control unit 30 controls the cooling mechanism 230b to cool the gas exhaust pipe 220b.

[0103] Thereafter, when a predetermined amount or more of solid objects have precipitated in a section of gas exhaust pipe 220b (for example, when the pressure on pressure gauge 218 is higher than a threshold), control unit 30 switches valve unit 222b to a closed state and switches valve unit 222a to an open state. With valve unit 222b in the closed state, control unit 30 stops cooling by cooling mechanism 230b and causes removal mechanism 240b to remove the solid objects. Furthermore, with valve unit 222a in the open state, control unit 30 causes cooling mechanism 230a to cool gas exhaust pipe 220a.

[0104] In the above description, two gas exhaust pipes, two cooling mechanisms, and two removal mechanisms are provided, but three or more gas exhaust pipes, three or more cooling mechanisms, and three or more 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] Advantages of the Second Embodiment The storage system 200A includes a plurality of cooling mechanisms and a plurality of removal mechanisms. Therefore, while one mechanism is cooling or heating, the other mechanism can be heating or cooling. Therefore, 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 solid objects that have precipitated in a section of the gas exhaust pipe 220 by flowing the heat medium Hm therethrough. The third embodiment differs from the first embodiment in that the removal mechanism 300 scrapes off solid objects that have precipitated in a section of the gas exhaust pipe 220. Components that have the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0107] Fig. 6 is a schematic diagram illustrating a storage system according to a 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 includes 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, and therefore a description thereof will be 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, but the heat medium Hm does not flow through it.

[0110] (Removal Mechanism) The removal mechanism 300 is a mechanism that scrapes off solid objects that have precipitated in a section of the gas exhaust pipe 220. That is, in the third embodiment, the removal mechanism 300 is a mechanism that physically removes solid objects from the inner wall surface of the gas exhaust pipe 220. As shown in Figures 6 and 7 , the removal mechanism 300 includes a support shaft 312 and a scraping unit 320.

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

[0112] The scraping unit 320 is provided on the support shaft 312. In this embodiment, the scraping unit 320 is provided at the tip of the support shaft 312. The scraping unit 320 rotates in accordance with the rotation of the support shaft 312. As the scraping unit 320 rotates, it comes into contact with the inner wall of the gas exhaust pipe 220 and scrapes off solid objects that have deposited on the inner wall of the gas exhaust pipe 220.

[0113] The scraping portion 320 may have any shape, but in this 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. It is preferable that multiple support portions 322 are provided at equal intervals in the vertical direction. For example, in this embodiment, six support portions 322 are provided. The support portions 322 may have any structure or number. For example, each support portion 322 may have a foldable or extendable structure made of multiple members. The radial direction here refers to the radial direction when the direction in which the gas exhaust pipe 220 extends is defined as the axial direction.

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

[0115] The scraping material 326 is not limited to a fluororesin material, and may be any material that can scrape off solid matter deposited on the inner wall of the gas exhaust pipe 220. The number of scraping materials 326 may also be any number.

[0116] The control unit 30 drives a drive unit 310 (e.g., a motor) provided in the removal mechanism 300 to rotate the support shaft 312. As a result, the scraping unit 320 rotates in conjunction with the rotation of the support shaft 312, and scrapes off solid objects precipitated in the gas exhaust pipe 220. When the removal mechanism 300 rotates within the gas exhaust pipe 220, the solid objects within the gas exhaust pipe 220 are scraped off and fall vertically downward. In other words, the solid objects scraped off by the removal mechanism 300 fall back into the solution tank 210 and dissolve in the object liquid L2 stored in the solution tank 210.

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

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

[0119] Specifically, as shown in FIG. 8, a removal mechanism 300C according to this modified example 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 may be operated by an operator to control the drive of the removal mechanism 300C. The drive unit 310C may also have a motor mounted in the handle. In this case, the drive unit 310C may automatically control the drive of the removal mechanism 300C, 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 inside the gas exhaust pipe 220. The support shaft 312C is a member that can move along the axial direction of the gas exhaust pipe 220. The cross-sectional shape of the support shaft 312C may be any shape. The axial direction here refers to the direction in which the gas exhaust pipe 220 extends.

[0122] The scraping portion 320C is provided on the support shaft 312C. In this embodiment, the scraping portion 320C is provided at the tip of the support shaft 312. The scraping portion 320C moves in the axial direction as the support shaft 312C moves along the axial direction. The scraping portion 320C moves in the axial direction while in contact with the inner wall of the gas exhaust pipe 220, thereby scraping off solid objects deposited on the inner wall of the gas exhaust pipe 220.

[0123] The scraping portion 320C may have any shape, but in this embodiment, it includes a support portion 322C and a scraping material 326C. The support portion 322C is a disk-shaped member that extends radially outward from the support shaft 312C. The support portion 322C is provided so that the center of the support portion 322C overlaps the center of the support shaft 312C.

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

[0125] In this embodiment, the scraping material 326C is a member made of fluororesin, but is not limited to this and may be any member as long as it can scrape off solid objects deposited on the inner wall of the gas exhaust pipe 220. The shape of the scraping material 326C may also be ring-shaped.

[0126] The control unit 30 controls, for example, the drive unit 310C to move the support shaft 312C in the axial direction. The scraping unit 320C scrapes off solid objects by moving axially in accordance with the movement of the support shaft 312C while the scraping material 326C is in contact with the inner wall of the gas exhaust pipe 220. Specifically, the scraping unit 320C reciprocates vertically within the gas exhaust pipe 220. The lower end of the scraping unit 320C descends vertically to the lower end of the cooling mechanism 330 or below the lower end. This allows solid objects precipitated in a certain section of the gas exhaust pipe 220 to be scraped off throughout that section. Furthermore, the lower end of the scraping unit 320C ascends vertically to a position above the side pipe 221 of the gas exhaust pipe 220. That is, as the support shaft 312C moves, the scraping unit 320C can move in the axial direction a distance longer than a portion of the gas exhaust pipe 220. By moving in the axial direction a distance longer than a portion of the gas exhaust pipe 220, the scraping unit 320C can scrape off solid objects over a portion of the gas exhaust pipe 220 without interrupting the flow of gas through the gas exhaust pipe 220.

[0127] (Effects of the Third Embodiment) In the storage system 200B, the removal mechanism 300B rotates to scrape off solid objects that have precipitated in a portion of the gas exhaust pipe 220. The removal mechanism 300B is provided with a scraping unit 320 that is equal to or longer than the portion of the gas exhaust pipe 220, and is therefore able to scrape off solid objects that have precipitated in the portion of the gas exhaust pipe 220 throughout that portion. This makes it possible to prevent objects from precipitating beyond the portion of the gas exhaust pipe 220. Therefore, the liquid containing the objects can be appropriately stored.

[0128] Furthermore, in the storage system 200C, the removal mechanism 300C moves in the axial direction to scrape off solid objects that have precipitated in a certain section of the gas exhaust pipe 220. The removal mechanism 300C can move in the axial direction longer than the certain section of the gas exhaust pipe 220, and therefore can scrape off solid objects that have precipitated throughout that section. This makes it possible to prevent objects from precipitating beyond the certain section of the gas exhaust pipe 220. Therefore, the liquid containing the objects can be appropriately stored.

[0129] Fourth Embodiment In the third embodiment, the cooling mechanism 230 stops the operation of the solution tank 210 when switching to the removal mechanism 300 or the removal mechanism 300C. The fourth embodiment differs from the third embodiment in that a plurality of cooling mechanisms 230 and a plurality of removal mechanisms 300 are provided. Components having the same functions as those in the third embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0130] FIG. 9 is a schematic diagram illustrating a storage system according to a 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 includes a removal mechanism 300a and a removal mechanism 300b.

[0132] The gas exhaust pipe 220a and the gas exhaust pipe 200b in the fourth embodiment are similar to those in the second embodiment, and therefore a description thereof will be omitted.

[0133] (Cooling Mechanism) Differences between the cooling mechanism 230a and the cooling mechanism 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 and cools the partial section of the gas exhaust pipe 220a. When the valve unit 222a is in an open state, the cooling mechanism 230a is supplied with a refrigerant Cm under the control of the control unit 30, thereby cooling the partial section of the gas exhaust pipe 220a and causing solid objects to precipitate in the gas exhaust pipe 220a.

[0135] 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 unit 222b is in an open state, the cooling mechanism 230b is supplied with a refrigerant Cm under the control of the control unit 30, thereby cooling the partial section of the gas exhaust pipe 220b and causing solid objects to precipitate in the gas exhaust pipe 220b.

[0136] (Removal Mechanism) Differences between the removal mechanisms 300a and 300b in the fourth embodiment and the removal mechanism 300 in the third embodiment will be described.

[0137] The removal mechanism 300a is provided in a partial section of the gas exhaust pipe 220a and removes solid objects that have deposited in that partial section of the gas exhaust pipe 220a. The removal mechanism 300a rotates when the valve unit 222a is closed to remove solid objects that have deposited in that partial section of the gas exhaust pipe 220a. The removal mechanism 300b is provided in a partial section of the gas exhaust pipe 220b and rotates when the valve unit 222b is closed to remove solid objects that have deposited in that partial section of the gas exhaust pipe 220b.

[0138] The removal mechanism 300a and the removal mechanism 300b may be replaced by a removal mechanism 300C. In this case, the removal mechanism 300C scrapes off solid objects deposited inside 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 opens the valve 222a of the gas exhaust pipe 220a and causes the cooling mechanism 230a to cool the gas exhaust pipe 220a. When a predetermined amount or more of solid matter has precipitated in a section of the gas exhaust pipe 220a (for example, when the pressure of the pressure gauge 218 is higher than the threshold), the control unit 30 closes the valve 222a and opens the valve 222b. With the valve 222a closed, the control unit 30 stops cooling by the cooling mechanism 230a and causes the removal mechanism 300a to remove the solid matter. With the valve 222b open, the control unit 30 also cools the gas exhaust pipe 220b by the cooling mechanism 230b.

[0140] Thereafter, when a predetermined amount or more of solid objects have precipitated in a section of gas exhaust pipe 220b (for example, when the pressure on pressure gauge 218 is higher than a threshold), control unit 30 switches valve unit 222b to a closed state and valve unit 222a to an open state. With valve unit 222b in the closed state, control unit 30 stops cooling by cooling mechanism 230b and causes removal mechanism 300b to remove the solid objects. Furthermore, with valve unit 222a in the open state, control unit 30 causes cooling mechanism 230a to cool gas exhaust pipe 220a.

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

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

[0143] Fifth Embodiment In the above-described embodiments, the cooling mechanism 230 includes an inlet pipe 232, a pipe section 234, and an outlet pipe 236, and is configured to cause the refrigerant Cm to flow through the pipe section 234. However, the fifth embodiment differs from the above-described embodiments in that it includes a shell 510 and a tube 520. Fig. 10 is a cross-sectional schematic diagram of the cooling mechanism according to the fifth embodiment.

[0144] 10 , the cooling mechanism 230c according to the fifth embodiment is provided midway through the gas exhaust pipe 220. In other words, the cooling mechanism 230c according to the fifth embodiment constitutes a partial section of the gas exhaust pipe 220, and cools the interior of the cooling mechanism 230c to cool the partial section of the gas exhaust pipe 220. The cooling mechanism 230c according to the fifth embodiment includes a shell 510 and a tube 520.

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

[0146] Gas G in the solution tank 210 is introduced into the shell 510 via the gas exhaust pipe 220 and the opening 512. Gas G in the shell 510 is exhausted to the outside via the opening 514 and the gas exhaust pipe 220. In other words, the shell 510 constitutes a partial section of the gas exhaust pipe 220.

[0147] The tube 520 is a tubular member provided inside the shell 510. An inlet pipe 516 and an outlet pipe 518 are connected to the tube 520. A refrigerant Cm is introduced into the tube 520 via the inlet pipe 516. The refrigerant Cm introduced into the tube 520 cools the gas G inside the shell 510. The refrigerant Cm inside the tube 520 is discharged to the outlet pipe 518. For example, a heat exchanger that cools the refrigerant Cm by heat exchange is provided between the inlet pipe 516 and the outlet pipe 518, and the refrigerant Cm after cooling inside the shell 510 is cooled by the heat exchanger via the outlet pipe 518 and is introduced from the outlet pipe 518 into the inlet pipe 516.

[0148] As described above, in the fifth embodiment, the shell 510 (a section of the gas exhaust pipe 220) is cooled by the refrigerant Cm in the tube 520, thereby solidifying the gaseous object (monomer D in this example) contained in the gas G. The solidified object precipitates in the shell 510.

[0149] The removal mechanism 240c according to this 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 according to this embodiment includes a shell 510 and a tube 520. In the removal mechanism 240c, a heat medium Hm is introduced into the tube 520. The solid object precipitated in the shell 510 is heated and liquefied by the heat medium Hm flowing through the tube 520. For example, a heat exchanger that heats the heat medium Hm by heat exchange is provided between the inlet pipe 516 and the outlet pipe 518. The heat medium Hm after heating the inside of the shell 510 is heated by the heat exchanger via the outlet pipe 518 and introduced from the outlet pipe 518 into the inlet pipe 516.

[0150] In this way, by heating the inside of the shell 510 by the removal mechanism 240c, the solid object (monomer D in this example) deposited in the shell 510 is liquefied and removed.

[0151] (Effects of the Present Disclosure) The storage system according to the first aspect of the present disclosure includes a solution tank 210 for storing a target liquid containing a liquid target, a gas exhaust pipe 220 connected to the solution tank 210 for discharging gas G from the solution tank 210, and a cooling mechanism 230 for cooling a section of the gas exhaust pipe 220 to cause the gaseous target contained in the gas to precipitate as a solid.

[0152] This allows the target object to be solidified in a section of the gas exhaust pipe where the cooling mechanism is provided, and the position of the solidified target object can be determined. In other words, it is possible to prevent the solid target object from precipitating beyond the section of the gas exhaust pipe. Therefore, it is possible to appropriately store the liquid containing the target object.

[0153] A storage system according to a second aspect of the present disclosure is the storage system according to the first aspect, wherein the cooling mechanism 230 is a tubular member that surrounds a partial section of the gas exhaust pipe 220. In the partial section of the gas exhaust pipe where the cooling mechanism is provided, the target object can be solidified, and the position of the solidified target object can be grasped. In other words, precipitation of the solid target object can be suppressed beyond the partial section of the gas exhaust pipe. Therefore, the liquid containing the target object can be appropriately stored.

[0154] A storage system according to a third aspect of the present disclosure is the storage system according to the second aspect, in which a refrigerant Cm flows inside the cooling mechanism 230 to cool a section of the gas exhaust pipe 220. This allows the cooling mechanism to precipitate a solid object.

[0155] A storage system according to a fourth aspect of the present disclosure is the storage system according to any one of the first to third aspects, and includes a removal mechanism 240 that removes solid objects that have precipitated in a section of the gas exhaust pipe 220. This allows the precipitated solid objects to be removed by the cooling mechanism.

[0156] A storage system according to a fifth aspect of the present disclosure is the storage system according to the fourth aspect, wherein the removal mechanism 240 heats a section of the gas exhaust pipe 220 to melt and remove the solid object. This allows the solid object precipitated by the cooling mechanism to be melted and removed.

[0157] A storage system according to a 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 that surround a partial section of the gas exhaust pipe 220, the cooling mechanism 230 cools the partial section of the gas exhaust pipe 220 by flowing a refrigerant Cm therethrough, and the removal mechanism 240 melts and removes solid objects by flowing a heat medium Hm therethrough. This allows the solid objects precipitated by the cooling mechanism to be melted and removed.

[0158] A storage system according to a 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 within the gas exhaust pipe 220, and a scraping unit 320 provided on the support shaft 312 to scrape off solid objects precipitated in a section of the gas exhaust pipe 220. Therefore, the solid objects precipitated by the cooling mechanism can be scraped off.

[0159] A storage system according to an 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 unit 320 scrapes off solid objects by rotating in conjunction with the rotation of the support shaft 312 while in contact with the inner wall of the gas exhaust pipe 220. In this manner, the scraping unit has a length equal to at least a portion of the gas exhaust pipe, and can therefore scrape off precipitated solid objects over that section.

[0160] A storage system according to a 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 unit 320 scrapes off the solid object by moving axially in conjunction with the movement of the support shaft 312 while in contact with the inner wall of the gas exhaust pipe 220. In this manner, the scraping unit can move axially for a distance greater than a portion of the gas exhaust pipe, and therefore can scrape off the precipitated solid object over that entire section.

[0161] A storage system according to a 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 is connected to the solution tank 210, and supplies a seal gas Sg that does not react with the target substance into the solution tank 210. Therefore, the seal gas can push out and discharge components that react with the target substance from the solution tank, making it possible to suppress deterioration of the target substance.

[0162] A storage system according to an eleventh aspect of the present disclosure is the storage system according to any one of the first to tenth aspects, wherein the object has sublimation properties, which makes it easier for the solid object to be precipitated by the cooling mechanism.

[0163] Although the embodiments of the present invention have been described above, the embodiments are not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the scope of what is called equivalents. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments.

[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 section 90 Crystallization tank 100 Stirring section 200, 200A to 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 transfer medium L2 Target liquid M Reaction solvent P Polyester solution Pd, L Dissolution liquid Pm Polyester raw material R Residual substance

Claims

1. A storage system comprising: a solution tank for storing a target liquid containing a liquid 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 the gas exhaust pipe to deposit the gaseous object contained in the gas as a solid.

2. The storage system according to claim 1, wherein the cooling mechanism is a tubular member surrounding a part of the gas exhaust pipe.

3. The storage system according to claim 2, wherein a refrigerant for cooling a part of the gas exhaust pipe flows inside the cooling mechanism.

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

5. The storage system according to claim 4, wherein the removal mechanism heats a part of the gas exhaust pipe to melt and remove the solid object.

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

7. The storage system according to claim 4, wherein 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 object deposited in a part of the gas exhaust pipe.

8. The support shaft is rotatable, and the scraping portion rotates as the support shaft rotates while in contact with the inner wall of the gas exhaust pipe to scrape the solid object. The storage system according to claim 7.

9. The support shaft is movable along the axial direction of the gas exhaust pipe, and the scraping portion moves in the axial direction as the support shaft moves while in contact with the inner wall of the gas exhaust pipe to scrape the solid object. The storage system according to claim 7.

10. The solution tank is connected to a gas supply pipe for supplying a seal gas that does not react with the object into the solution tank. The storage system according to claim 1 or claim 2.

11. The object has sublimability. The storage system according to claim 1 or claim 2.

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