Membrane separation system

Abstract

To provide a membrane separation system for evaluating the performance of a semipermeable membrane module capable of performing at least one arbitrary membrane separation method selected from a plurality of membrane separation methods.SOLUTION: A membrane separation system comprising: a plurality of pipes to be connected to at least one semipermeable membrane module; and a plurality of valves provided in the pipes, wherein the membrane separation system is capable of performing at least one arbitrary membrane separation method selected from a plurality of membrane separation methods by opening and closing the valves, and is used for performance evaluation of the semipermeable membrane module.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a membrane separation system. [Background technology]

[0002] Membrane separation methods (liquid concentration methods) using semipermeable membranes (semipermeable membrane modules) include a variety of membrane separation methods (reverse osmosis (RO) method, forward osmosis (FO) method, osmotically assisted reverse osmosis (OARO) (brine concentration) method, etc. (see, for example, Patent Document 1 (WO 2020 / 179594)). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 179594 Summary of the Invention [Problem to be solved by the invention]

[0004] When evaluating the performance of a semipermeable membrane module for multiple membrane separation methods, it has been necessary to prepare multiple membrane separation systems (evaluation systems) for each membrane separation method, because the water flow method differs for each membrane separation method (see Figures 20(a), (b), (c1), and (c2)). However, it would be desirable to provide a membrane separation system that can evaluate the performance of semipermeable membrane modules for a variety of membrane separation methods using a single system.

[0005] Therefore, an object of the present invention is to provide a membrane separation system for evaluating the performance of a semipermeable membrane module, which is capable of carrying out at least one membrane separation method selected from a plurality of membrane separation methods. [Means for solving the problem]

[0006] [1] A system comprising a plurality of pipes for connecting to at least one semipermeable membrane module and a plurality of valves provided on the pipes, By opening and closing the valve, it is possible to carry out at least one membrane separation method selected from a plurality of membrane separation methods, A membrane separation system used for evaluating the performance of the semipermeable membrane module.

[0007] [2] The membrane separation system according to [1], wherein the at least one optional membrane separation method includes a combination of a plurality of membrane separation methods.

[0008] [3] The membrane separation system according to [1], which has an instrument necessary for the performance evaluation on at least one of the inlet side and the outlet side of the semipermeable membrane module.

[0009] [4] The membrane separation system according to [1], comprising a tank, a booster pump, and a high-pressure pump.

[0010] [5] A plurality of pipes respectively connected to the plurality of semipermeable membrane modules; The membrane separation system according to [1], wherein any one or more of the membrane separation methods can be carried out on any number of semipermeable membrane modules selected from the plurality of semipermeable membrane modules by opening and closing the valve.

[0011] [6] The membrane separation system according to [1], further comprising a monitoring function for analyzing the results of the performance evaluation. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a membrane separation system for evaluating the performance of a semipermeable membrane module, which is capable of carrying out at least one arbitrary membrane separation method selected from a plurality of membrane separation methods. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating an example of a membrane separation system according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing an example of a usage form of the membrane separation system shown in FIG. [Figure 3] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 4] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 5] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 6] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 7] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 8] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 9] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 10] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 11] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 12] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 13] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 14] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 15] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 16] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 17] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 18]FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 19] FIG. 2 is a schematic diagram showing another example of the use of the membrane separation system shown in FIG. [Figure 20] FIG. 1 is a schematic diagram showing a conventional membrane separation system used in multiple membrane separation methods. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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.

[0015] <Membrane separation system> A membrane separation system is a system that can separate a target component from a solvent (dispersion medium) in a target solution containing the target component and the solvent (dispersion medium) using a semipermeable membrane (semipermeable membrane module).

[0016] Referring to FIG. 1, the membrane separation system of this embodiment includes a plurality of pipes (solid lines in FIG. 1) for connecting to at least one semipermeable membrane module 1a, 1b, 1c, and a plurality of valves (V) provided on the pipes. In the membrane separation system of this embodiment, it is possible to carry out at least one membrane separation method selected from a plurality of membrane separation methods (RO method, FO method, OARO method, etc.) by opening and closing the valve (V). In other words, the membrane separation system of this embodiment is a multi-type membrane separation system that can be operated by a plurality of membrane separation methods in a single system.

[0017] The membrane separation system of this embodiment can be used to evaluate the performance of the semipermeable membrane modules 1a, 1b, and 1c. Performance evaluation means, for example, evaluating the permeability of the semipermeable membrane modules 1a, 1b, and 1c (semipermeable membrane 10), and includes measurement of the permeability coefficient. Such performance evaluation may be performed for multiple types of membrane separation methods. In such cases, by performing the evaluation using the membrane separation system (evaluation system) of this embodiment, it becomes possible to evaluate the performance of semipermeable membrane modules for various membrane separation methods using a single membrane separation system, without the need to prepare multiple membrane separation systems for each membrane separation method.

[0018] The multiple membrane separation methods are not particularly limited as long as they are membrane separation methods using semipermeable membrane modules, and examples thereof include reverse osmosis (RO), forward osmosis (FO), osmotically assisted reverse osmosis (OARO), and ultrafiltration (see Figures 20(a), (b), (c1), and (c2)).

[0019] The semipermeable membrane modules 1a, 1b, and 1c each have a semipermeable membrane 10 and a first chamber 11 and a second chamber 12 separated by the semipermeable membrane 10.

[0020] For example, when performing the osmotic pressure-assisted reverse osmosis (OARO) method, a semipermeable membrane module 1a, 1b, 1c has a semipermeable membrane 10 and a first chamber 11 and a second chamber 12 separated by the semipermeable membrane. A high-pressure target solution is passed through the first chamber 11 of the semipermeable membrane module 1a, 1b, 1c, and a low-pressure auxiliary solution (such as the target solution) is passed through the second chamber 12. The solvent (such as water) contained in the target solution in the first chamber 11 is transferred to the auxiliary solution in the second chamber 12 via the semipermeable membrane 10, and the concentrated target solution (concentrated solution) is discharged from the first chamber 11, and the diluted auxiliary solution (diluted solution) is discharged from the second chamber 12 (see Figures 20(c1) and (c2) and Figures 9 to 11).

[0021] The membrane separation system includes devices necessary for carrying out membrane separation treatments using a plurality of membrane separation methods. The membrane separation system includes, for example, a tank 3 (TK), a booster pump 21 (BP) and a high-pressure pump 22 (HPP). Two or more tanks may be provided, two or more booster pumps may be provided, and two or more high-pressure pumps may also be provided.

[0022] When performing the RO method, the OARO method, or the like, the target solution is pressurized by a pressurizing device or the like. An example of the pressurizing device is a high-pressure pump 22 that can pressurize the target solution while feeding it into the first chamber 11. The pressurizing device may be a device other than a pump, and may be, for example, a device that pressurizes the liquid in the first chamber 11 from outside the semipermeable membrane module 1.

[0023] The target solution or the like to be subjected to membrane separation treatment may be subjected to pretreatment to remove fine particles, microorganisms, scale components, etc. contained in the solution. As the pretreatment, various known pretreatments used in membrane separation techniques or the like can be carried out, and examples thereof include filtration using an NF membrane, UF membrane, MF membrane, etc., addition of sodium hypochlorite, addition of a flocculant, activated carbon adsorption treatment, ion exchange resin treatment, etc. Such pretreatment is preferably carried out before the target solution or the like is supplied to the semipermeable membrane module. For example, as in the membrane separation system shown in Fig. 1, a pretreatment device 4 may be provided to perform the above-mentioned pretreatment on the liquid stored in the tank 3. Note that, it is also possible to temporarily perform only the pretreatment of the liquid stored in the tank 3 by opening and closing the valve (V) so that the liquid stored in the tank 3 passes through the pretreatment device 4 and is returned to the tank 3 by the booster pump 21.

[0024] Any one or more membrane separation methods performed in the membrane separation system of this embodiment may include a combination of multiple membrane separation methods. That is, by opening and closing the valve (V), a combination of multiple membrane separation methods can be operated (see Figures 18 and 19).

[0025] Furthermore, when the membrane separation system is equipped with a plurality of pipes connected to a plurality of semipermeable membrane modules 1a, 1b, and 1c, respectively, at least one arbitrary membrane separation method can be performed on any number of semipermeable membrane modules selected from the plurality of semipermeable membrane modules 1a, 1b, and 1c by opening and closing the valve (V) (see Figures 3 to 8, 10, 11, 13, 14, 16, and 17). Note that operation using a single semipermeable membrane module selected from the plurality of semipermeable membrane modules 1a, 1b, and 1c is also possible (see Figures 6 to 8, 11, 14, and 17).

[0026] The membrane separation system of this embodiment may have instruments necessary for performance evaluation (flowmeter, pressure gauge, thermometer, etc.) on at least one of the inlet side (upstream side) and outlet side (downstream side) of the semipermeable membrane modules 1a, 1b, 1c. The membrane separation system may further have a monitoring function for analyzing the results of the performance evaluation.

[0027] <Membrane separation system usage> 2 to 19 show examples of how the membrane separation system shown in FIG. 1 can be used. 2 to 19, the valve (V) is opened and closed so that the liquid flows through the pipes (flow paths) shown by solid lines and does not flow through the pipes shown by dotted lines. The liquid flows in the direction shown by the arrows.

[0028] (RO method usage) 2 to 8 show a use form for carrying out a reverse osmosis (RO) method. In FIG. 2, the RO method is carried out in semipermeable membrane modules 1a, 1b, and 1c. In FIG. 3, the RO method is carried out in semipermeable membrane modules 1a and 1b. In FIG. 4, the RO method is carried out in semipermeable membrane modules 1b and 1c. In FIG. 5, the RO method is carried out in semipermeable membrane modules 1a and 1c. In FIG. 6, the RO method is carried out in a semipermeable membrane module 1a. In FIG. 7, the RO method is carried out in the semipermeable membrane module 1b. In FIG. 8, the RO method is carried out in a semipermeable membrane module 1c.

[0029] (How the OARO method is used) 9 to 11 show a use configuration for carrying out an osmotically assisted reverse osmosis (OARO) process. In FIG. 9, the OARO method is carried out in semipermeable membrane modules 1a, 1b, and 1c. In FIG. 10, the OARO method is carried out in semipermeable membrane modules 1b and 1c. In FIG. 11, the OARO process is carried out in a semipermeable membrane module 1c.

[0030] (Usage of the FO method) 12 to 17 show a use form for carrying out the forward osmosis (FO) method. 12 to 14 show a usage mode in which the FO method is carried out in a countercurrent manner, and FIGS. 15 to 17 show a usage mode in which the FO method is carried out in a parallel current manner.

[0031] Regardless of the type of membrane separation method, in each semipermeable membrane module 1a, 1b, 1c, the flow direction of the liquid on both sides of the semipermeable membrane 10 (in the first chamber 11 and the second chamber 12) may be any direction, and may be opposite directions (countercurrent flow) or parallel directions (parallel flow).

[0032] In Figs. 12 and 15, the FO method is carried out in semipermeable membrane modules 1a, 1b, and 1c. In Figs. 13 and 16, the FO method is carried out in semipermeable membrane modules 1b and 1c. In Figures 14 and 17, the FO method is carried out in a semipermeable membrane module 1c.

[0033] (Combination of multiple membrane separation methods) As shown in Figures 18 and 19, the RO method and the OARO method may be used in combination. In FIG. 18, the RO method is carried out in the semipermeable membrane module 1a, and the OARO method is carried out in the semipermeable membrane modules 1b and 1c. In FIG. 19, the RO method is carried out in the semipermeable membrane modules 1a and 1b, and the OARO method is carried out in the semipermeable membrane module 1c.

[0034] The membrane separation system of this embodiment can be a multistage membrane separation system (concentration system, etc.) equipped with a plurality of semipermeable membrane modules 1a, 1b, and 1c (FIGS. 2 to 5, 9, 10, 12, 13, 15, 16, 18, and 19). In this case, the valve (V) is opened and closed so that the first chambers 11 and / or the second chambers 12 of two or more of the multiple semipermeable membrane modules 1a, 1b, and 1c are connected via piping (so that liquid can flow).

[0035] (semi-permeable membrane) Examples of the semipermeable membrane used in this embodiment include semipermeable membranes called 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.

[0036] Typically, RO and FO membranes have pore sizes of approximately 2 nm or less, and UF membranes have pore sizes of approximately 2 to 100 nm. NF membranes have a relatively low rejection rate for ions and salts compared to other RO membranes, and typically have pore sizes of approximately 1 to 2 nm. When an RO membrane, FO membrane, or NF membrane is used as the semipermeable membrane, the salt rejection rate of the RO membrane, FO membrane, or NF membrane is preferably 90% or higher.

[0037] The material constituting the semipermeable membrane is not particularly limited, but examples thereof include cellulose-based resins, polysulfone-based resins, polyamide-based resins, etc. The semipermeable membrane is preferably made of a material containing at least one of a cellulose-based resin and a polysulfone-based resin.

[0038] The cellulose-based resin is preferably a cellulose acetate-based resin. Cellulose acetate-based resins are resistant to chlorine, a disinfectant, and have the characteristic of being able to inhibit the growth of microorganisms. The cellulose acetate-based resin is preferably cellulose acetate, and from the viewpoint of durability, more preferably cellulose triacetate.

[0039] The polysulfone-based resin is preferably a polyethersulfone-based resin. The polyethersulfone-based resin is preferably a sulfonated polyethersulfone.

[0040] In the drawings, the semipermeable membranes of the semipermeable membrane modules are depicted as flat membranes for simplification, but the shape of the semipermeable membranes is not particularly limited. The semipermeable membranes may be flat membranes such as spiral membranes (spiral-type semipermeable membranes) or hollow fiber membranes (hollow fiber-type semipermeable membranes), but hollow fiber membranes are preferred. Hollow fiber membranes are advantageous in that they have a smaller membrane thickness than flat membranes and can increase the membrane area per module, thereby increasing the permeation efficiency.

[0041] When the semipermeable membrane is a hollow fiber membrane and membrane separation treatment is performed by the RO method or the OARO method, it is preferable that in each semipermeable membrane module, the first chamber is outside the hollow fiber membrane and the second chamber is inside the hollow fiber membrane (hollow portion). This is because even if the solution flowing inside the hollow fiber membrane is pressurized, the pressure loss may become large and it may be difficult to pressurize sufficiently, and also because, although hollow fiber membranes generally easily maintain their structure against external pressure, the hollow fiber membrane may be damaged if the internal pressure becomes too high.

[0042] A specific example of a hollow fiber membrane is a membrane with a single layer structure composed entirely of a cellulose-based resin. However, the single layer structure referred to here does not necessarily mean a membrane with a uniform layer throughout; for example, it may be a membrane that is non-uniform in the thickness direction. Specifically, the membrane may have a dense layer on the outer surface, which serves as a separation active layer that essentially determines the pore size of the hollow fiber membrane, and the inner surface side may have a lower density than the dense layer. Since the dense layer essentially serves as a separation active layer that determines 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 accurate control of the movement of molecules from the outside to the inside of the hollow fiber membrane.

[0043] Another specific example of a hollow fiber membrane is a two-layer membrane having a dense layer of polyphenylene resin (e.g., sulfonated polyethersulfone) on the outer surface of a support layer (e.g., a layer made of polyphenylene oxide). Another example is a two-layer membrane having a dense layer of polyamide resin on the outer surface of a support layer (e.g., a layer made of polysulfone or polyethersulfone). [Explanation of symbols]

[0044] 1, 1a, 1b, 1c semipermeable membrane module, 10 semipermeable membrane, 11 first chamber, 12 second chamber, 21 booster pump (BP), 22 high pressure pump (HPP), 3 tank (TK), 4 pretreatment device, V valve.

Claims

1. A plurality of pipes for connecting to at least one semipermeable membrane module, and a plurality of valves provided on the pipes, By opening and closing the valve, it is possible to carry out at least one membrane separation method selected from a plurality of membrane separation methods, A membrane separation system used for evaluating the performance of the semipermeable membrane module.

2. 10. The membrane separation system of claim 1, wherein the optional at least one membrane separation method comprises a combination of multiple membrane separation methods.

3. The membrane separation system according to claim 1 , wherein at least one of the inlet side and the outlet side of the semipermeable membrane module has an instrument necessary for the performance evaluation.

4. The membrane separation system of claim 1 , comprising a tank, a booster pump, and a high-pressure pump.

5. a plurality of pipes respectively connected to the plurality of semipermeable membrane modules; 2. The membrane separation system according to claim 1, wherein any one or more of the at least one membrane separation methods can be performed on any number of semipermeable membrane modules selected from the plurality of semipermeable membrane modules by opening and closing the valves.

6. The membrane separation system according to claim 1 , further comprising a monitoring function for analyzing the results of the performance evaluation.

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