Concentration system

Abstract

In a concentration system using osmotic-assisted reverse osmosis (OARO), the need for large-scale equipment is suppressed even when the concentration of the target solution is high. [Solution] A concentration system for obtaining a concentrated solution containing a concentrated target component by separating the solvent from the target solution discharged from the coagulation tank 1. The concentration system comprises at least one semipermeable membrane module 21, the coagulation tank and the semipermeable membrane module are directly connected, the semipermeable membrane module has a semipermeable membrane 210 and a first chamber 211 and a second chamber 212 separated by the semipermeable membrane, the target solution is flowed into the first chamber and an auxiliary solution having osmotic pressure is flowed into the second chamber, and because the target solution has a higher pressure than the auxiliary solution, the solvent contained in the target solution in the first chamber is transferred to the auxiliary solution in the second chamber via the semipermeable membrane in the semipermeable membrane module, the target solution is concentrated to obtain a concentrated solution, a diluted auxiliary solution is discharged from the second chamber and the diluted solution is supplied to the coagulation tank.

Description

Technical Field

[0001] The present invention relates to a concentration system. Background Art

[0002] A membrane separation method (osmosis-assisted reverse osmosis (OARO) method, brine concentration (BC) method) is known, in which a high-pressure target solution is flowed into a first chamber of a semipermeable membrane module comprising a semipermeable membrane, and a first chamber and a second chamber partitioned by the semipermeable membrane, and a low-pressure auxiliary solution (such as the target solution) is flowed into the second chamber, so that a solvent (such as water) contained in the target solution in the first chamber moves to the auxiliary solution in the second chamber through the semipermeable membrane, whereby the concentrated target solution (concentrated liquid) is discharged from the first chamber, and the diluted auxiliary solution (diluted liquid) is discharged from the second chamber. The OARO method makes it possible to reduce the energy required for membrane separation (concentration) treatment using the reverse osmosis (RO) method, and to obtain a concentrated solution with a higher concentration.

[0003] It has also been studied to achieve higher-level concentration by combining pressure membrane separation methods such as the OARO method and the RO method (see, for example, Patent Document 1 (International Publication No. WO 2024 / 214605)). Prior Art Literature Patent Literature

[0004] Patent Document 1 International Publication No. WO 2024 / 214605 Summary of the Invention Problems to be Solved by the Invention

[0005] The concentration (osmotic pressure) of the target solution supplied to the membrane separation system (i.e., the liquid supplied to the first chamber of the semipermeable membrane module) must be lower than a predetermined concentration determined by the configuration and operating conditions of the apparatus. The liquid in the second chamber of the semipermeable membrane module is of a lower concentration than the liquid supplied to the first chamber. If the concentration of the target solution in the first chamber of the same module is higher, the osmotic pressure of the target solution will exert a force in the opposite direction to the direction that would move the solvent in the target solution to the second chamber. Therefore, in order to perform the desired membrane separation (concentration of the target solution), it is necessary to increase the pressure of the target solution, which increases energy consumption.

[0006] Therefore, if the target solution has a concentration higher than the predetermined concentration mentioned above (for example, about 7% by mass in the case of saline solution), it was necessary to concentrate the diluted solution of the target solution obtained by the OARO method using the RO method, and then dilute the target solution with the resulting RO concentrate before supplying it to the membrane separation system, as disclosed in Patent Document 1.

[0007] However, in such membrane separation systems, the total volume of liquid processed by the membrane separation system increases because the diluent and the RO concentrate dependent on the diluent are returned to the target solution. This leads to problems such as an increase in the number of semipermeable membrane modules that make up the membrane separation system. Furthermore, there was room for improvement from a cost perspective.

[0008] Therefore, this disclosure aims to suppress the need for large-scale equipment in a concentration system using osmotic pressure-assisted reverse osmosis (OARO), even when the concentration of the target solution is high. [Means for solving the problem]

[0009] [1] A concentration system for obtaining a concentrated liquid containing the target component by separating the solvent from a target solution containing the target component discharged from a coagulation tank, The system comprises at least one semipermeable membrane module, including a first semipermeable membrane module, The coagulation tank and the first semipermeable membrane module are directly connected. The at least one semipermeable membrane module comprises a semipermeable membrane and a first chamber and a second chamber separated by the semipermeable membrane. The target solution is poured into the first chamber, An auxiliary solution having osmotic pressure is flowed into the second chamber. Because the target solution has a higher pressure than the auxiliary solution, in the at least one semipermeable membrane module, the solvent contained in the target solution in the first chamber migrates through the semipermeable membrane to the auxiliary solution in the second chamber, and the target solution is concentrated to obtain the concentrated solution, and the diluted auxiliary solution is discharged from the second chamber. The diluent is supplied to the solidification tank. Concentration system.

[0010] [2] The concentration system according to [1], comprising a plurality of semipermeable membrane modules.

[0011] [3] The concentration system according to [1] or [2], wherein at least a portion of the group consisting of the target solution and the concentrate is used as the auxiliary solution.

[0012] [4] further comprising at least one reverse osmosis module, The dilution concentrated by the at least one reverse osmosis module is supplied to the target solution discharged from the coagulation tank. The concentration system according to any one of [1] to [3], wherein the permeate that has passed through at least one reverse osmosis module is supplied to the coagulation tank.

[0013] [5] The concentration system according to any one of [1] to [4], wherein the semipermeable membrane is a hollow fiber membrane. [Effects of the Invention]

[0014] According to this disclosure, in a concentration system using osmotic-assisted reverse osmosis (OARO), it is possible to suppress the need for large-scale equipment even when the concentration of the target solution is high. [Brief explanation of the drawing]

[0015] [Figure 1] It is a schematic diagram showing an example of the concentration system according to an embodiment. [Figure 2] It is a schematic diagram showing another example of the concentration system according to an embodiment. [Figure 3] It is a schematic diagram showing another example of the concentration system according to an embodiment. [Figure 4] It is a schematic diagram showing another example of the concentration system according to an embodiment. [Figure 5] It is a schematic diagram showing another example of the concentration system according to an embodiment. [Figure 6] It is a schematic diagram showing another example of the concentration system according to an embodiment. [Figure 7] It is a schematic diagram showing another example of the concentration system according to an embodiment. [Figure 8] It is a schematic diagram showing an example of the concentration system according to a reference embodiment. [Figure 9] It is a schematic diagram showing another example of the concentration system according to a reference embodiment. Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals denote the same or corresponding parts.

[0017] <Concentration System> The concentration system of the present embodiment is a system for obtaining a concentrated liquid in which a target component is concentrated by separating a solvent from a target solution containing the target component discharged from a coagulation tank.

[0018] (Coagulation Tank) In this embodiment, the "coagulation tank" refers to a bathtub that holds a coagulation solution for solidifying raw materials, and is used for wet coagulation of spinning (fibers), semipermeable membranes, artificial leather, synthetic leather (faux leather), etc. Examples of raw materials for spinning include polyacrylonitrile, viscose rayon, copper ammonia rayon, polyvinyl alcohol, polyurethane, polyamide, and cellulose ester. Examples of raw materials for synthetic leather include polyurethane, polyvinyl chloride, and polyamide.

[0019] Here, wet coagulation is a method in which the raw material is dissolved in the target component, and the coagulation solution is introduced into a coagulation tank that holds the coagulation solution to remove the target component and extract the coagulated raw material. Therefore, in this embodiment, the target solution refers to a solution in which the target component is dissolved in the solvent (mainly water) in the coagulation solution.

[0020] The target solution of this embodiment includes a solvent and a target component. The target component includes at least one selected from the group consisting of organic solvents and inorganic compounds. Examples of organic solvents include methanol, ethanol, propanol, ethylene glycol (EG), propylene glycol (PG), glycerin, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), hydrazine, ethylenediamine, 2,4-toluenediisocyanate, N-methyl-2-pyrrolidone, tetrahydrofuran (THF), dioxane, methyl ethyl ketone, acetic acid, methyl acetate, ethyl acetate, butyl acetate, acetone, and the like. Examples of inorganic compounds include sulfates such as nitrates, sodium sulfate, sodium lauryl sulfate, zinc sulfate, copper sulfate, and ammonium sulfate; chlorides such as zinc chloride, calcium chloride, lithium chloride, and magnesium chloride; thiocyanates such as boric acid, borates, acetates, and sodium thiocyanate. The target component is appropriately selected depending on the raw materials.

[0021] The concentration of the target solution, i.e., the concentration of the target component in the target solution, is, for example, 5% by mass or more. Preferably, the concentration of the target solution is 7% by mass or more in terms of saline solution, or an osmotic pressure of 7% by mass or more. The target solution may also contain uncoagulated raw materials as the target component.

[0022] Referring to Figure 1, wet solidification is performed, for example, by discharging a stock solution 5 containing raw materials and target components from a nozzle 6 into the target solution 2 in a solidification tank 1, and then pulling out the solidified material from the stock solution 5 from the target solution 2. Pulling out the solidified material is performed, for example, by rollers 3 and 4.

[0023] For example, a method for producing hollow fiber membranes by a wet coagulation method using a coagulation tank is disclosed in Japanese Patent No. 7396464.

[0024] (Concentration system) Referring to Figure 1, the concentration system of this embodiment comprises a first semipermeable membrane module 21, which is at least one semipermeable membrane module. The first semipermeable membrane module 21 has a semipermeable membrane 210 and a first chamber 211 and a second chamber 212 separated by the semipermeable membrane 210. The coagulation tank 1 and the first semipermeable membrane module 21 (first chamber 211) are directly connected.

[0025] The target solution is flowed into the first chamber 211, and an auxiliary solution with osmotic pressure is flowed into the second chamber 212. The auxiliary solution contains the same components as the target solution. The target solution has a higher pressure (hydrostatic pressure) than the auxiliary solution. That is, in the first semipermeable membrane module 21, the liquid in the first chamber 211 (target solution) has a higher pressure than the liquid in the second chamber 212 (auxiliary solution). As a result, in the first semipermeable membrane module 21, the solvent (water, etc.) contained in the target solution in the first chamber 211 is transferred to the auxiliary solution in the second chamber 212 via the semipermeable membrane 210, and the target solution is concentrated to obtain a concentrated solution. The concentrated solution is discharged from the first chamber 211, and the diluted solution is discharged from the second chamber 212.

[0026] The target solution is pressurized by a pressurizing device. Examples of pressurizing devices include a high-pressure pump capable of pressurizing the target solution and sending it into the first chamber 211. The pressurizing device may be other than a pump; for example, it may be a device that pressurizes the liquid in the first chamber 211 from outside the first semipermeable membrane module 21.

[0027] In the first semipermeable membrane module 21, the direction of liquid flow on both sides of the semipermeable membrane 210 (between the first chamber 211 and the second chamber 212) may be in any direction relative to each other, and may be in opposing directions (counter-flow method) or parallel directions (parallel-flow method).

[0028] The concentration system of this embodiment may be a multi-stage concentration system equipped with multiple semipermeable membrane modules. For example, in Figure 2, three semipermeable membrane modules (first semipermeable membrane module 21, second semipermeable membrane module 22, and third semipermeable membrane module 23) are depicted as multiple semipermeable membrane modules, but the multiple semipermeable membrane modules can be any number of semipermeable membrane modules, for example, two or more. Hereinafter, the concentration system of this embodiment will be described as being equipped with three semipermeable membrane modules, but it is not limited to this.

[0029] Each of the first semipermeable membrane module 21, the second semipermeable membrane module 22, and the third semipermeable membrane module 23 has semipermeable membranes 210, 220, and 230, and first chambers 211, 221, 231 and second chambers 212, 222, 232 separated by semipermeable membranes.

[0030] In this case, a concentration channel is provided, which is formed by connecting the first chambers 211, 221, and 231 of the first semipermeable membrane module 21, the second semipermeable membrane module 22, and the third semipermeable membrane module 23, respectively. That is, the concentration channel consists of the first chambers 211, 221, and 231, and the channel connecting them. In at least a portion of the first semipermeable membrane module 21, the second semipermeable membrane module 22, and the third semipermeable membrane module 23, it is preferable that the first chambers are connected in series. In a portion of the first semipermeable membrane module 21, the second semipermeable membrane module 22, and the third semipermeable membrane module 23, the first chambers may be connected in parallel.

[0031] Furthermore, a dilution channel is provided, which is formed by connecting the second chambers 212, 222, and 232 of the first semipermeable membrane module 21, the second semipermeable membrane module 22, and the third semipermeable membrane module 23, respectively. That is, the dilution channel consists of the second chambers 212, 222, and 232, and a channel connecting them. In at least a portion of the first semipermeable membrane module 21, the second semipermeable membrane module 22, and the third semipermeable membrane module 23, it is preferable that the second chambers are connected in series. In a portion of the first semipermeable membrane module 21, the second semipermeable membrane module 22, and the third semipermeable membrane module 23, the second chambers may be connected in parallel.

[0032] The target solution flows through the concentration channel. The direction in which the target solution flows is not particularly limited. For example, in Figure 2, the target solution flows in the following order: first chamber 211 of the first semipermeable membrane module 21, first chamber 221 of the second semipermeable membrane module 22, and first chamber 231 of the third semipermeable membrane module 23.

[0033] An auxiliary solution with osmotic pressure flows through the dilution channel. The direction in which the auxiliary solution flows is not particularly limited. For example, the auxiliary solution flows in the following order: second chamber 232 of the third semipermeable membrane module 23, second chamber 222 of the second semipermeable membrane module 22, and second chamber 212 of the first semipermeable membrane module 21.

[0034] For example, as disclosed in Japanese Patent Publication No. 7020512, in a multi-stage concentration system, a first dilution channel may be formed by connecting all first chambers of semipermeable membrane modules in series and connecting the second chambers of the first module group (odd-numbered semipermeable membrane modules from the downstream side of the concentration channel) in series, and a second dilution channel may be formed by connecting the second chambers of the second module group (even-numbered semipermeable membrane modules from the downstream side of the concentration channel) in series, and these two channels may be connected in parallel.

[0035] In the concentration system of this embodiment, the diluent is supplied to the coagulation tank 1.

[0036] Conventionally, the target solution obtained by the OARO method was diluted and concentrated using the RO method, and the target solution was then diluted with the resulting RO concentrate before being supplied to the membrane separation system. In this case, the volume of circulating water was large, so many semipermeable membrane modules had to be installed. In addition, pressurizing equipment for sending out the target solution had to be installed for each semipermeable membrane module. Thus, conventional concentration systems had the problem of being large in size.

[0037] In contrast, by supplying the diluent to the coagulation tank 1 instead of the target solution, as in the conventional method, the increase in the total volume of liquid processed by the concentration system can be suppressed. As a result, the number of semipermeable membrane modules in the concentration system can be reduced, thereby suppressing the need for larger equipment. For example, compared to the concentration system disclosed in Patent Document 1, the concentration system of this embodiment is expected to reduce the number of semipermeable membrane modules installed by up to one-tenth.

[0038] A replenishment solution may be supplied to the coagulation tank 1. The replenishment solution may be, for example, water.

[0039] As an auxiliary solution, a portion of at least one of the group consisting of the target solution and the concentrate may be used. For example, referring to Figure 3, a portion of the concentrate discharged from the first chamber 231 of the third semipermeable membrane module 23 may be used as an auxiliary solution. It is preferable that the channel for supplying a portion of the concentrate as an auxiliary solution to the dilution channel (second chamber) is provided with a mechanism to reduce the liquid pressure. Examples of such mechanisms include devices that maintain a high pressure on the upstream side and reduce the pressure on the downstream side, such as an automatic control valve, and devices that have a mechanism to convert energy recovered from a pressurized supply liquid into driving auxiliary energy for a pump or the like, such as an energy recovery device.

[0040] The concentration system of this embodiment may further include at least one reverse osmosis module. In this case, at least one reverse osmosis module is connected to the coagulation tank 1 and the second chamber 212 of the first semipermeable membrane module 21. The diluent concentrated by the reverse osmosis module (RO concentrate) is supplied to the target solution discharged from the coagulation tank, and the diluent that has permeated through the reverse osmosis module (RO permeate) is supplied to the coagulation tank.

[0041] For example, referring to Figure 4, the second chamber 212 of the first semipermeable membrane module 21 is connected to the first chamber 111 of the reverse osmosis module 11, and the second chamber 112 of the reverse osmosis module 11 is connected to the coagulation tank 1. The diluent discharged from the second chamber 212 of the first semipermeable membrane module 21 is supplied to the first chamber 111 of the reverse osmosis module 11. In the reverse osmosis module 11, the water contained in the diluent moves into the second chamber 112 via the reverse osmosis membrane 110, so that the diluent is concentrated in the first chamber 111 to obtain RO concentrate, and RO permeate that has permeated through the semipermeable membrane is obtained in the second chamber 112. The RO concentrate is supplied to the target solution discharged from the coagulation tank 1. The RO permeate is supplied to the coagulation tank 1.

[0042] Referring to Figure 5, the concentration system of this embodiment may include a concentration meter 30 for measuring the concentration of the target solution in the coagulation tank 1. For example, if the measurement value of the concentration meter 30 is lower than a predetermined range (lower limit concentration), the switching valve 40 adjusts so that the diluent is not supplied to the coagulation tank 1. This allows the concentration of the target solution to be returned to the predetermined range. Examples of the switching valve 40 include a three-way valve. Furthermore, the diluent that was not supplied to the coagulation tank may be returned to the target solution.

[0043] A portion of the target solution may be used as an auxiliary solution. For example, referring to Figure 6, a portion of the target solution may be supplied to the second chamber 212 of the first semipermeable membrane module 21, a portion of the target solution concentrated in the first semipermeable membrane module 21 may be supplied to the second chamber 222 of the second semipermeable membrane module 22, and a portion of the target solution concentrated in the second semipermeable membrane module 22 may be supplied to the second chamber 232 of the third semipermeable membrane module 23.

[0044] The solidification tank 1 may be partitioned by dividers. For example, referring to Figure 7, the solidification tank 1 may be divided into a first tank 101, a second tank 102, and a third tank 103 by dividers 7 and 8. Generally, the concentration of the target solution in the solidification tank 1 increases as the raw material is wound up (to the right in Figure 7). That is, the concentration of the target component is lowest in the first tank 101 and highest in the third tank 103. Therefore, by withdrawing the target solution from any of the tanks, the target solution of a predetermined concentration can be concentrated in this concentration system. Note that the number of dividers is not particularly limited, as long as the solidification tank 1 is partitioned into multiple tanks.

[0045] Furthermore, multiple solidification tanks may be used (not shown). For example, by using a first solidification tank, a second solidification tank, and a third solidification tank, a configuration similar to solidification tank 1 shown in Figure 7 can be achieved.

[0046] (others) The target solution may be pretreated to remove fine particles, microorganisms, scale components, etc. contained in the solution. Various known pretreatments used in seawater desalination technology can be performed as pretreatments, such as filtration using NF membranes, UF membranes, MF membranes, etc., addition of sodium hypochlorite, addition of coagulants, activated carbon adsorption treatment, and ion exchange resin treatment. Such pretreatment is preferably performed before supplying the target solution and auxiliary solution to the semipermeable membrane module.

[0047] Theoretically, membrane separation using OARO is possible if the osmotic pressure difference (absolute value) between the target solution (concentrated liquid) flowing into the first chamber (high pressure side) and the auxiliary solution (diluted liquid) flowing into the second chamber (low pressure side) is smaller than the pressure of the target solution. In this case, it is preferable that the difference between the osmotic pressure of the target solution and the osmotic pressure of the auxiliary solution is 30% or less of the pressure of the target solution.

[0048] In OARO concentration (membrane separation) using a semipermeable membrane module, osmotic pressure acting in the opposite direction to the solvent movement from the first chamber to the second chamber is less likely to occur. Therefore, concentration can be carried out at a lower pressure (pump pressure) than in the RO method. For this reason, in the concentration system of this embodiment that performs OARO concentration, the power consumption of pumps and other equipment can be reduced, and the energy efficiency of concentration can be increased.

[0049] In RO (reverse osmosis) concentration, the osmotic pressure of the concentrated target solution on one side of the semipermeable membrane is generated in the opposite direction to the pressure exerted by the pump. Therefore, when the osmotic pressure of the concentrated target solution reaches the pump pressure, the pressure exerted by the pump and the osmotic pressure of the target solution acting in the opposite direction become balanced, preventing water from passing through the semipermeable membrane any further, and thus halting the concentration process.

[0050] In contrast, in membrane separation (concentration) using the OARO method, the concentration difference (osmotic pressure difference) of the liquid supplied to the first and second chambers in each semipermeable membrane module is small, making it less likely to generate osmotic pressure that would hinder concentration like in the RO method. Therefore, a concentration system using the OARO method can achieve a higher final concentration of the target solution than a concentration system using only the RO method. In principle, it is possible to concentrate the target solution to a saturation concentration.

[0051] (semi-permeable membrane) Examples of semipermeable membranes used in this embodiment include reverse osmosis membranes (RO membranes), forward osmosis membranes (FO membranes), nanofiltration membranes (NF membranes), and ultrafiltration membranes (UF membranes). The semipermeable membrane is preferably a reverse osmosis membrane, a forward osmosis membrane, or a nanofiltration membrane. When a reverse osmosis membrane, a forward osmosis membrane, or a nanofiltration membrane is used as the semipermeable membrane, the pressure of the liquid (target solution) in the first chamber is preferably 0.5 to 10.0 MPa.

[0052] Typically, the pore size of RO and FO membranes is about 2 nm or less, and the pore size of UF membranes is about 2 to 100 nm. NF membranes are RO membranes with relatively low ion and salt rejection rates, and typically, the pore size of NF membranes is about 1 to 2 nm. When RO membranes, FO membranes, or NF membranes are used as semipermeable membranes, the salt removal rate of the RO membrane, FO membrane, or NF membrane is preferably 90% or higher.

[0053] The materials constituting the semipermeable membrane are not particularly limited, but examples include cellulose resins, polysulfone resins, and polyamide resins. Preferably, the semipermeable membrane is composed of a material containing at least one of a cellulose resin and a polysulfone resin.

[0054] The cellulose resin is preferably a cellulose acetate resin. Cellulose acetate resins have the characteristic of being resistant to chlorine, which is a disinfectant, and can suppress the growth of microorganisms. The cellulose acetate resin is preferably cellulose acetate, and more preferably cellulose triacetate from the viewpoint of durability.

[0055] The polysulfone resin is preferably a polyethersulfone resin. The polyethersulfone resin is preferably a sulfonated polyethersulfone.

[0056] In the drawings, the semipermeable membrane of the semipermeable membrane module is depicted as a flat membrane for simplification, but the shape of the semipermeable membrane is not particularly limited. The semipermeable membrane may be a flat membrane such as a spiral membrane (spiral-type semipermeable membrane), or a hollow fiber membrane (hollow fiber-type semipermeable membrane), but a hollow fiber membrane is preferred. Compared to a flat membrane, a hollow fiber membrane has advantages in that it has a smaller film thickness, and the membrane area per module can be increased, thereby improving penetration efficiency.

[0057] When the semipermeable membrane is a hollow fiber membrane, it is preferable that in each semipermeable membrane module, the first chamber is on the outside of the hollow fiber membrane and the second chamber is on the inside (hollow part) of the hollow fiber membrane. This is because even if the solution flowing inside the hollow fiber membrane is pressurized, the pressure loss may be large and it may be difficult to pressurize sufficiently. Also, while hollow fiber membranes generally maintain their structure against external pressure, they may be damaged if the internal pressure becomes too high.

[0058] A specific example of a hollow fiber membrane is a single-layer membrane composed entirely of cellulose-based resin. However, the single-layer structure referred to here does not necessarily mean that the entire layer is uniform; for example, it may be a membrane that is non-uniform in the thickness direction. Specifically, it may be a membrane having a dense layer on the outer surface, where this dense layer substantially acts as a separation active layer that defines the pore size of the hollow fiber membrane, and the inner surface side has a lower density than the dense layer. Since the dense layer substantially acts as a separation active layer that defines the pore size of the hollow fiber membrane, when the solution outside the hollow fiber membrane is pressurized, having a dense layer on the outer surface of the hollow fiber membrane allows for more precise control of the movement of molecules from the outside to the inside of the hollow fiber membrane.

[0059] Another specific example of a hollow fiber membrane is a two-layer membrane having a support layer (for example, a layer made of polyphenylene oxide) with a dense layer made of a polyphenylene resin (for example, sulfonated polyethersulfone) on its outer surface. Yet another example is a two-layer membrane having a support layer (for example, a layer made of polysulfone or polyethersulfone) with a dense layer made of a polyamide resin on its outer surface.

[0060] <Reference form> Figures 8 and 9 are schematic diagrams showing an example of a reference embodiment of a concentration system. The reference embodiment of the concentration system differs from the embodiment of the concentration system in that a reverse osmosis module 11 is interposed between the coagulation tank 1 and the first semipermeable membrane module 21. In other words, in the reference embodiment of the concentration system, the coagulation tank 1 and the first semipermeable membrane module 21 are not directly connected. Even in such a concentration system, a concentrated liquid in which the target component is concentrated can be obtained, but there is a risk that the size of the equipment cannot be suppressed. Figure 9 differs from Figure 8 in that it further includes a concentration meter 30 for measuring the concentration of the target solution in the coagulation tank 1 and a switching valve 40. [Explanation of symbols]

[0061] 1 Coagulation tank, 2 Target solution, 3,4 Rollers, 5 Stock solution, 6 Nozzle, 7,8 Partition, 11 Reverse osmosis module, 21 First semipermeable membrane module, 22 Second semipermeable membrane module, 23 Third semipermeable membrane module, 30 Concentration meter, 40 Switching valve, 101 First tank, 102 Second tank, 103 Third tank, 110 Reverse osmosis membrane, 111 First chamber, 112 Second chamber, 210, 220, 230 Semipermeable membrane, 211, 221, 231 First chamber, 212, 222, 232 Second chamber.

Claims

1. A concentration system for obtaining a concentrated solution containing the target component by separating the solvent from a target solution containing the target component discharged from a coagulation tank, The system comprises at least one semipermeable membrane module, including a first semipermeable membrane module, The coagulation tank and the first semipermeable membrane module are directly connected. The at least one semipermeable membrane module comprises a semipermeable membrane and a first chamber and a second chamber separated by the semipermeable membrane. The target solution is poured into the first chamber. An auxiliary solution having osmotic pressure is flowed into the second chamber. Because the target solution has a higher pressure than the auxiliary solution, in the at least one semipermeable membrane module, the solvent contained in the target solution in the first chamber migrates through the semipermeable membrane to the auxiliary solution in the second chamber, and the target solution is concentrated to obtain the concentrated solution, and the diluted auxiliary solution is discharged from the second chamber. The diluent is supplied to the solidification tank. Concentration system.

2. The concentration system according to claim 1, comprising a plurality of semipermeable membrane modules.

3. The concentration system according to claim 1 or 2, wherein at least a portion of the group consisting of the target solution and the concentrated liquid is used as the auxiliary solution.

4. It also includes at least one reverse osmosis module, The diluted solution, concentrated by at least one reverse osmosis module, is supplied to the target solution discharged from the coagulation tank. The concentration system according to claim 1 or 2, wherein the permeate that has passed through the at least one reverse osmosis module is supplied to the coagulation tank.

5. The concentration system according to claim 1 or 2, wherein the semipermeable membrane is a hollow fiber membrane.

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