Evaluation method and apparatus for forward osmosis membrane modules

Abstract

To provide an evaluation method and an evaluation device capable of accurately measuring the practical performance of a forward osmosis membrane.SOLUTION: An evaluation method of a forward osmosis membrane module having a space separated by a forward osmosis membrane having a porous support and a separation function layer laminated on the porous support includes: a step to connect a space at a separation function layer side to a raw material liquid line and a space at a porous support side to an induction solution line; and a step to remove a solvent in a raw material liquid into an induction solution while adjusting physical pressure difference between forward osmosis membranes to be substantially constant in a range of more than 0 kPa and 200 kPa or less via the forward osmosis membrane.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to an evaluation method and apparatus for forward osmosis membrane modules. [Background technology]

[0002] Among selective separation technologies for liquid mixtures, membrane separation technology is used in a wide range of fields, including seawater desalination, ultrapure water production, wastewater treatment, and the food industry. Well-known membranes used in membrane separation technology include microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, and reverse osmosis membranes. In recent years, forward osmosis membranes, which can achieve high concentrations that cannot be achieved with reverse osmosis membranes, have been attracting attention.

[0003] Forward osmosis membranes use the osmotic pressure difference generated across a separation layer as the driving force to move water from the raw material solution to the target solution according to the principle of forward osmosis. Generally, since the separation layer is often a thin film, composite semipermeable membranes are often used as forward osmosis membranes, in which the separation layer is laminated and physically supported on a support membrane such as a porous support or nonwoven fabric.

[0004] A forward osmosis membrane can be used as a forward osmosis membrane module, comprising an outer casing (module housing) and at least one forward osmosis membrane housed within the outer casing and separating spaces within the outer casing. Generally, a forward osmosis membrane module is connected to a raw material line that delivers a raw material liquid containing a solvent to one side of the space separated by the forward osmosis membrane, and to an induction solution line that delivers an induction solution with a higher osmotic pressure than the raw material liquid to the other side of the space, for evaluation and practical use.

[0005] For example, Patent Document 1 describes a forward osmosis treatment method that includes a forward osmosis step, in which a feed solution (raw material liquid) and a draw solution (inducing solution) with a higher osmotic pressure than the feed solution are brought into contact via a semipermeable membrane, thereby moving water contained in the feed solution into the draw solution. Patent Document 1 further describes a forward osmosis treatment method in which the physical pressure difference between the feed solution and the draw solution is adjusted in the forward osmosis step so as to reduce fluctuations in the amount of permeate, which is the amount of water that moves from the feed solution to the draw solution.

[0006] Patent Document 2 describes a pressure-regulating forward osmosis apparatus comprising an inflow water (raw material liquid) storage tank, an induction solution storage tank for containing a high-concentration induction solution, a forward osmosis membrane module, a high-pressure pump installed on the piping from the inflow water storage tank to the forward osmosis membrane module and which adjusts its pressure based on external control to supply pressure to the forward osmosis membrane module, and a back pressure valve installed on the concentrated water piping discharged from the forward osmosis membrane module and which adjusts the pressure applied to the forward osmosis membrane module based on external control.

[0007] Patent Document 3 describes an evaluation apparatus for a reverse osmosis membrane module having a structure in which a high-concentration section to which a high-concentration side solution (induction solution) is supplied and a low-concentration section to which a low-concentration side solution (raw material solution) is supplied are separated by a semipermeable membrane. The evaluation apparatus comprises a means for supplying the high-concentration side solution to the high-concentration section, a means for supplying the low-concentration side solution to the low-concentration section, an electrodialysis machine, a reverse osmosis membrane module, a first introduction channel for introducing the discharged liquid from the high-concentration section into the electrodialysis machine, a second introduction channel for introducing the discharged liquid from the low-concentration section into the reverse osmosis membrane module, a first reflux channel for refluxing the concentrated liquid discharged from the electrodialysis machine to the high-concentration side solution supply means, a second reflux channel for refluxing the permeate discharged from the reverse osmosis membrane module to the low-concentration side solution supply means, a third introduction channel for introducing the desalted liquid discharged from the electrodialysis machine into the reverse osmosis membrane module, and a fourth introduction channel for introducing the concentrated liquid discharged from the reverse osmosis membrane module into the electrodialysis machine. Patent Document 3 further describes providing pressure adjustment means for both the high-concentration solution supply means and the low-concentration solution supply means.

[0008] Patent Document 4 describes a method for evaluating the water permeability of a filter membrane having a support layer and a separation function layer. This method includes immersing the filter membrane in an electrolyte, applying one or more alternating currents of one or more frequencies to the electrolyte through electrodes positioned on one and the other sides of the filter membrane in the direction of water permeability, measuring the impedance between one and the other side of the filter membrane while the alternating current is applied, applying pressure to the electrolyte from one or the other side of the filter membrane, and evaluating the water permeability of the filter membrane based on the relaxation characteristics of the impedance corresponding to one or more specific frequencies with respect to pressure. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] International Publication No. 2020 / 022218 [Patent Document 2] Korean Published Patent Publication No. 2013-0140370 [Patent Document 3] Japanese Patent Publication No. 2016-16384 [Patent Document 4] Japanese Patent Publication No. 2021-16811 [Overview of the project] [Problems that the invention aims to solve]

[0010] In practical use of the forward osmosis method, the raw material liquid and the induction solution are generally supplied to the forward osmosis membrane module by a liquid delivery means such as a pump. Therefore, regardless of the user's intentions, physical pressure is often generated at the start of operation and during operation in a direction that temporarily peels the separation functional layer away from the support membrane. The inventors have found that if the physical durability of the forward osmosis membrane is low, such physical pressure can cause the separation functional layer to peel away from the support membrane or to rupture, resulting in a decrease in membrane performance.

[0011] However, while forward osmosis is a separation method that uses the osmotic pressure difference generated through the separation functional layer as its driving force, conventional evaluation methods for forward osmosis membrane modules have been performed by adjusting the physical pressure of the raw material liquid and the induction solution placed through the forward osmosis membrane to be equal. Therefore, conventional evaluation methods could not take into account the effects of physical pressure generated in the direction of peeling the separation functional layer from the support membrane during actual use, and thus could not accurately evaluate the practical performance of the forward osmosis membrane including the support membrane and the separation functional layer.

[0012] In view of the above issues, one of the objectives of this disclosure is to provide an evaluation method and an evaluation apparatus that can accurately measure the practical performance of a forward osmosis membrane. [Means for solving the problem]

[0013] Examples of embodiments of this disclosure are listed below. [1] A method for evaluating a forward osmosis membrane module having a space separated by a forward osmosis membrane, The above-mentioned forward osmosis membrane comprises a support membrane with a porous support and a separation functional layer provided on the porous support. The above method is as follows: The process involves preparing a raw material line for supplying a raw material liquid containing a solvent to the above-mentioned forward osmosis membrane module, and an induction solution line for supplying an induction solution with a higher osmotic pressure than the above-mentioned raw material liquid to the above-mentioned forward osmosis membrane module. The process involves connecting the space on the separation functional layer side of the above-mentioned forward osmosis membrane module to the raw material liquid line, and connecting the space on the porous support side to the induction solution line. The process involves moving the solvent in the raw material liquid into the induction solution while adjusting the physical pressure difference between the raw material liquid and the induction solution to be constant within a range greater than 0 kPa and less than or equal to 200 kPa, with the porous support side being positive, through the above-mentioned forward osmosis membrane, either in countercurrent or parallel flow, and with the porous support side being positive. A method for evaluating forward osmosis membrane modules, including the method described above. [2] Before the step of connecting the forward osmosis membrane module to the raw material liquid line and the draw solution line, the method according to item 1, further comprising the step of adjusting the physical pressure of the draw solution to be greater than 0 kPa and not more than 200 kPa while circulating the draw solution outside the forward osmosis membrane module. [3] The method according to item 1 or 2, wherein the physical pressure difference is 20 kPa to 100 kPa. [4] Before the step of connecting the forward osmosis membrane module to the raw material liquid line and the draw solution line, the method according to any one of items 1 to 3, further comprising the step of adjusting the temperature difference between the raw material liquid and the draw solution to be within 10°C. [5] Before the step of connecting the forward osmosis membrane module to the raw material liquid line and the draw solution line, by adjusting the flow rates of the raw material liquid and the draw solution, after connecting the forward osmosis membrane module, the difference between the residence time of the raw material liquid in the space on the separation functional layer side and the residence time of the draw solution in the space on the porous support side is adjusted to be within 20 seconds. The method according to any one of items 1 to 4, further comprising this step. [6] The method according to any one of items 1 to 5, wherein the solvent is water. [7] The method according to item 6, wherein after supplying the raw material liquid to the forward osmosis membrane module, the draw solution is supplied. [8] The method according to any one of items 1 to 7, wherein the solution containing the raw material liquid after being supplied to the forward osmosis membrane module and exiting the forward osmosis membrane module does not return to the raw material liquid tank. [9] Measuring at least one difference selected from the group consisting of conductivity, refractive index, total organic carbon, chemical oxygen demand, biochemical oxygen demand, absorbance, and transmittance between the raw material liquid and the solution containing the raw material liquid after being supplied to the forward osmosis membrane module and exiting the forward osmosis membrane module, and comparing the same items with the draw solution to evaluate the performance of the forward osmosis membrane. The method according to item 8.

[10] The method according to item 8 or 9, wherein the evaluation is started 10 seconds or more after the raw material liquid is first discharged from the forward osmosis membrane module.

[11] The method according to any one of items 1 to 10, wherein the derivative solute contained in the derivative solution is at least one selected from inorganic salts and hydrophilic organic compounds.

[12] The method according to item 11, wherein the number-average molecular weight of the derived solute is 20 to 300.

[13] The method according to item 11 or 12, wherein the derived solute contains a monovalent salt.

[14] The method according to any one of items 11 to 13, wherein the derived solute comprises an alcohol having 1 to 4 carbon atoms and / or acetonitrile.

[15] The method according to any one of items 11 to 14, wherein the concentration of the above-mentioned derivative solute is 1% by mass or more based on the total mass of the above-mentioned derivative solution.

[16] The method according to any one of items 1 to 15, wherein the above-mentioned forward osmosis membrane module is a hollow fiber membrane module.

[17] An evaluation apparatus for a forward osmosis membrane module having a forward osmosis membrane, A raw material liquid tank for storing the raw material liquid, A raw material liquid line connects the above raw material liquid tank to the above forward osmosis membrane module, A raw material supply means that supplies the raw material from the raw material tank to the forward osmosis membrane module through the raw material line, An induction solution tank containing an induction solution with a higher osmotic pressure than the above raw material liquid, An induction solution line connects the induction solution tank to the forward osmosis membrane module. An induction solution supply means that supplies the induction solution from the induction solution tank to the forward osmosis membrane module through the induction solution line, A pressure adjustment means installed on the induction solution line, capable of physically pressurizing the induction solution before, during, and after evaluation of the forward osmosis membrane module, wherein the pressure adjustment means is configured to maintain a constant physical pressure difference between the induction solution and the physical pressure P of the raw material liquid via the forward osmosis membrane, within a range greater than 0 kPa and less than or equal to 200 kPa. A pressure sensor is installed on the induction solution line and is capable of measuring the physical pressure of the induction solution. An evaluation device equipped with the following features.

[18] The evaluation apparatus described in item 17, which is an evaluation apparatus for a forward osmosis membrane module having a forward osmosis membrane having a support membrane with a porous support and a separation functional layer provided on the porous support.

[19] The evaluation apparatus according to item 17 or 18, wherein the induction solution line has a circulation structure that allows the induction solution to be circulated outside the forward osmosis membrane module before being connected to the forward osmosis membrane module, and comprises an induction solution bypass line that constitutes part of the circulation structure of the induction solution line and can be attached to and detached from the forward osmosis membrane module.

[20] The evaluation apparatus according to any one of items 17 to 19, wherein the raw material liquid line has a circulation structure that allows the raw material liquid to be circulated outside the forward osmosis membrane module before being connected to the forward osmosis membrane module, and comprises a raw material liquid bypass line that constitutes part of the circulation structure of the raw material liquid line and can be attached to and detached from the forward osmosis membrane module. [twenty one] An evaluation apparatus according to any one of items 17 to 20, comprising at least one selected from pressure adjustment means and temperature adjustment means on the raw material liquid line described above. [twenty two] An evaluation apparatus according to any one of items 17 to 21, further comprising a temperature control means on the induction solution line described above. [twenty three] An evaluation apparatus according to any one of items 17 to 22, comprising at least one selected from the group consisting of a pressure sensor, a temperature sensor, a flow rate sensor, a conductivity sensor, and a refractive index sensor on the raw material liquid line. [twenty four] An evaluation apparatus according to any one of items 17 to 23, comprising, on the induction solution line described above, at least one selected from the group consisting of a temperature sensor, a flow sensor, a conductivity sensor, and a refractive index sensor. [twenty five] An evaluation apparatus according to any one of items 17 to 24, wherein the raw material liquid tank or the induction solution tank, or both, are equipped with a temperature control means.

[26] The evaluation apparatus according to any one of items 17 to 25, wherein the raw material liquid tank or the induction solution tank, or both, are equipped with at least one selected from the group consisting of a temperature sensor, a conductivity sensor, and a refractive index sensor.

[27] An evaluation apparatus according to any one of items 17 to 26, comprising multiple sets of the above-mentioned raw material liquid line and the above-mentioned induction solution line, and capable of evaluating multiple forward osmosis membrane modules in parallel.

[28] An evaluation apparatus according to any one of items 17 to 27, configured to monitor in real time the values ​​and times measured by each sensor and store them in a database, so as to detect the difference between the values ​​of the raw material liquid, the derived solution, or both during solution circulation before evaluation and the values ​​during evaluation of the forward osmosis membrane module.

[29] The above raw material liquid line is equipped with a pressure adjustment means, a pressure sensor, and a flow rate sensor. The above induction solution line is further equipped with a flow sensor, The evaluation apparatus further comprises a control device coupled to the pressure sensor, flow sensor, and pressure adjustment means on the raw material liquid line and the induction solution line, respectively, and to the raw material liquid supply means and the induction solution supply means. The control device described above is configured to compare the physical pressure difference, flow rate, and minimum flow rate of the raw material liquid and the induction solution in real time, and to control the pressure adjustment means, the raw material liquid supply means, and the induction solution supply means to maintain a desired physical pressure difference and a flow rate greater than or equal to the minimum flow rate, as described in any one of items 17 to 28.

[30] The evaluation apparatus according to item 29, configured to maintain the above physical pressure difference in real time within ±1 kPa of the above desired physical pressure difference.

[31] The evaluation apparatus according to item 29 or 30, configured to determine and pre-control the pressure and flow rate of the induction solution before evaluating the forward osmosis membrane module by inputting information on the cross-sectional area of ​​the raw material supply section and the induction solution supply section within the forward osmosis membrane module, a desired physical pressure difference, and a desired minimum flow rate of the raw material.

[32] An evaluation apparatus according to any one of items 29 to 31, wherein the control device includes a processor configured to execute a proportional-integral-derivative control algorithm.

[33] The evaluation apparatus according to any one of items 17 to 32, wherein the induction solution line and / or induction solution tank further comprises concentration adjustment means capable of removing a solvent from the induction solution, adding a high concentration of induction solution to the induction solution, or adding an induction solute.

[34] An evaluation apparatus as described in any one of items 17 to 33, wherein the above-mentioned forward osmosis membrane module is a hollow fiber membrane module. [Effects of the Invention]

[0014] This disclosure provides an evaluation method and an evaluation apparatus that can accurately measure the practical performance of a forward osmosis membrane. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a schematic diagram of a cross-section of a forward osmosis membrane in the evaluation method of the present disclosure. [Figure 2] Figure 2 is a schematic diagram showing an example of an evaluation method for a forward osmosis membrane module using the evaluation apparatus of the present disclosure. [Figure 3] Figure 3 is a schematic diagram showing an example of a hollow fiber membrane module. [Figure 4]Figure 4 is a schematic diagram showing an example of an evaluation method for a hollow fiber membrane module using the evaluation apparatus of the present disclosure. [Modes for carrying out the invention]

[0016] Evaluation Method for Forward Osmosis Membrane Modules The evaluation method for the forward osmosis membrane module of this disclosure is as follows: The process involves preparing the raw material liquid line and the induction solution line, The process involves connecting the forward osmosis membrane module to the raw material liquid line and the induction solution line, The process includes a step of moving the solvent from the raw material liquid into the induction solution by causing the raw material liquid and the induction solution to flow in countercurrent or parallel current through a forward osmosis membrane (hereinafter also referred to as the "evaluation step"). In the evaluation step, the performance of the forward osmosis membrane module is evaluated while the physical pressure difference between the forward osmosis membranes is kept constant within a range greater than 0 kPa and less than or equal to 200 kPa, with the porous support side being positive.

[0017] In the practical use of forward osmosis, the raw material liquid and induction solution are generally supplied to the forward osmosis membrane module by a liquid delivery means such as a pump. Therefore, regardless of the user's intentions, physical pressure is often generated at the start of operation and during operation in a direction that temporarily peels the separation functional layer away from the support membrane. However, since forward osmosis is a separation method that uses the osmotic pressure difference generated through the separation functional layer as the driving force, conventional evaluation methods for forward osmosis membrane modules have been performed by adjusting the physical pressure of the raw material liquid and induction solution placed through the forward osmosis membrane to be equal. Therefore, conventional evaluation methods could not take into account the effect of the physical pressure generated in the direction that peels the separation functional layer away from the support membrane during practical use, and could not accurately evaluate the practical performance of the forward osmosis membrane including the support membrane and the separation functional layer. In this respect, the evaluation method of the present disclosure can appropriately take into account the effect of the physical pressure generated in the direction that peels the separation functional layer away from the porous support during the practical use of the forward osmosis membrane module by deliberately applying a certain physical pressure difference. Therefore, the method of the present disclosure can accurately evaluate the practical performance of the forward osmosis membrane including the support membrane and the separation functional layer.

[0018] <Forward Osmosis Membrane Module> The forward osmosis membrane module subject to the evaluation method of this disclosure has a space separated by a forward osmosis membrane, and the forward osmosis membrane is a forward osmosis membrane module having a support membrane with a porous support and a separation functional layer provided on the porous support. The space within the forward osmosis membrane module has a space on the porous support side and a space on the separation functional layer side. The forward osmosis membrane module may have an outer casing (module housing) that houses the forward osmosis membrane.

[0019] A forward osmosis membrane comprises a support membrane having a porous support and a separation functional layer provided on the porous support. The support membrane may be a composite of a substrate and a porous support, preferably without a substrate, and more preferably consisting only of a porous support. When the support membrane does not have a substrate, or consists only of a porous support, the solution diffuses easily within the support membrane, making it easier to maintain a high osmotic pressure between the forward osmosis membranes. In this respect, the water permeability of the forward osmosis membrane tends to be increased. However, the mechanical strength of the forward osmosis membrane is low, and the separation functional layer tends to peel off more easily from the porous support, so the effects of the evaluation method of this disclosure are more pronounced.

[0020] The substrate plays a role in providing strength to the porous support and / or separation functional layer, and is preferably porous to allow water to pass through. Generally, the substrate does not have a separation function, but it may have a separation function for solids such as particles. Examples of substrate materials include polymers such as polyester, polyamide, polyolefin, or mixtures or copolymers thereof. Examples of substrate forms include woven fabrics, nonwoven fabrics, mesh nets, and foamed sintered sheets. Generally, the substrate is a porous body with a larger pore size than the porous support or separation functional layer. The pore size of the substrate is generally around 0.1 μm to 100 μm, and is more generally evaluated by basis weight and air permeability, with a basis weight of 20 g / m². 2 ~150g / m 2 The air permeability is approximately 0.5 cc / cm³, as measured by the Frazier method (JIS L 1096). 2 ×sec)~30cc / (cm 2It is approximately ×sec. In this disclosure, it is preferable that the support film does not have these substrates.

[0021] The porous support plays a role in providing strength to the separation function layer. The porous support may have a separation function for solids such as particles, but it is preferable that the porous support substantially does not have a separation function for solutes such as ions. Here, substantially not having a separation function for solutes such as ions includes a state in which the separation function exhibited by the porous support is lower than the separation function exhibited by the separation function layer for solutes such as ions.

[0022] The material for the porous support is preferably a resin, particularly a thermoplastic resin. A thermoplastic resin is a resin made of chain-like polymers that exhibits the property of deforming or flowing when heated by an external force. Examples of thermoplastic resins include homopolymers or copolymers such as polysulfone, polyethersulfone, polyvinylidene fluoride, polyketone, polyamide, polyester, cellulose polymers, vinyl polymers, polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfone, and polyphenylene oxide. Examples of cellulose polymers include cellulose acetate and cellulose nitrate, and examples of vinyl polymers include polyethylene, polypropylene, polyvinyl chloride, chlorinated polyvinyl chloride, polyacrylonitrile, and polyvinyl alcohol. Derivatives of these polymers having arbitrary functional groups in the main chain, side chains, or terminals can also be used as thermoplastic resins. Thermoplastic resins can be used individually or as a blend of two or more.

[0023] When the support membrane is a composite of a substrate and a porous support, the thickness of the porous support is preferably 0.02 mm to 0.10 mm from the viewpoint of balancing water permeability resistance and strength. When the support membrane consists only of a porous support, from the viewpoint of strength, the thickness of the porous support is preferably 0.02 mm to 3.00 mm, more preferably 0.10 mm to 1.00 mm, and even more preferably 0.15 mm to 0.50 mm from the viewpoint of balancing water permeability resistance and strength. When the support membrane consists only of a porous support, the porous support is preferably in the form of a film, tube, or hollow fiber, or in a form obtained by chemically or physically deforming these. The porous support is preferably in the form of a hollow fiber. In the case of a hollow fiber, when modularized, the raw material liquid and induction solution can spread more uniformly to each membrane surface compared to a sheet-like membrane, allowing for greater enjoyment of the advantage of less evaluation variation in the present invention, and the size of the evaluation device can be reduced because a larger membrane area can be stored in a smaller space.

[0024] The separation layer is positioned on the porous support of the support membrane and is substantially responsible for solute separation in the forward osmosis membrane. More specifically, it is responsible for separating solutes such as ions dissolved in the solvent in the raw material liquid. The composition and thickness of the separation layer can be set according to the intended use of the forward osmosis membrane.

[0025] The material for the separation function layer can be, for example, a high-molecular polymer, an inorganic material, and an organic-inorganic hybrid material, as well as a material in which any inorganic or organic compound is dispersed or contained. The material for the separation function layer may be used individually or in combination of two or more types.

[0026] A separation functional layer made of polymers is a membrane that preferentially allows solvents to pass through while blocking solutes, thus possessing substantially separation capabilities. Examples of separation functional layers made of polymers include polyamides, polyvinyl alcohols, polypiperazineamides, sulfonated polyethersulfones, polypiperazineamides, and polyimides, as well as composite materials thereof. From the standpoint of balancing separation functionality with solvent permeability, polyamides may be the material for the separation functional layer among these.

[0027] A forward osmosis membrane module may have one or more forward osmosis membranes. More specifically, examples of forward osmosis membrane modules include a plate-type module having a planar forward osmosis membrane, a spiral-type module in which planar forward osmosis membranes are arranged in a spiral pattern around a perforated water collection tube, and a hollow fiber membrane module in which hollow fiber-shaped forward osmosis membranes are bundled together. The forward osmosis membrane module is preferably a hollow fiber membrane module. In the case of a hollow fiber membrane module, when modularized, the raw material liquid and induction solution are more easily distributed uniformly to each membrane surface compared to a sheet-type membrane module, allowing for greater enjoyment of the advantage of reduced evaluation variability in the present invention, and the size of the evaluation device can be reduced because a larger membrane area can be stored in a smaller space.

[0028] In general, a hollow fiber membrane module consists of bundles of hollow fiber membranes fixed within a module housing using an adhesive resin, thereby isolating the space on the porous support side from the space on the separation functional layer side. The module housing includes a raw material liquid inlet for introducing the raw material liquid, a raw material liquid outlet for recovering the raw material liquid, an induction solution inlet for introducing the induction solution, and an induction solution outlet for recovering the induction solution. The size and shape of the module housing are not particularly specified, but for example, a cylindrical housing with a diameter of 5 mm to 500 mm and a length of 20 mm to 10,000 mm can be used. As the adhesive resin, for example, urethane-based and epoxy-based adhesive resins can be used.

[0029] <Preparation process> The evaluation method for a forward osmosis membrane module according to this disclosure includes the steps of preparing a raw material line for supplying a raw material liquid containing a solvent to the forward osmosis membrane module, and an induction solution line for supplying an induction solution with a higher osmotic pressure than the raw material liquid to the forward osmosis membrane module. Preferably, the raw material line can recover and circulate the raw material liquid from the forward osmosis membrane module, and preferably, the induction solution line can recover and circulate the induction solution from the forward osmosis membrane module. When each solution is recovered and circulated from the forward osmosis membrane module, the amount of each solution used can be reduced, making it economical. Preferably, the raw material line can circulate the raw material liquid outside the forward osmosis membrane module before connecting it to the forward osmosis membrane module, and preferably, the induction solution line can circulate the induction solution outside the forward osmosis membrane module before connecting it to the forward osmosis membrane module. For details on the structure of the raw material line and the induction solution line, please refer to the section on "Evaluation Apparatus for Forward Osmosis Membrane Module" below. By circulating each solution outside the forward osmosis membrane module, the adjustment steps described below can be easily performed, and the evaluation accuracy can be improved immediately after the start of the evaluation.

[0030] The raw material solution contains a solvent. The raw material solution may or may not contain solutes such as ions to be separated. The solvent is preferably water. If the solvent is water, the membrane is less likely to be damaged beyond what is acceptable, allowing for safer evaluation and increasing the range of selectable forward osmosis membrane modules to be evaluated. Purified water is more preferably used as the raw material solution.

[0031] The induction solution is a solution with a higher osmotic pressure than the raw material solution. In actual use, the induction solution exhibits a higher osmotic pressure compared to the raw material solution containing the substance to be separated or concentrated, and has the function of moving the solvent from the raw material solution through the forward osmosis membrane. The induction solution has a high osmotic pressure due to containing a high concentration of induction solute. The concentration of the induction solute is preferably 1% by mass or more based on the total mass of the induction solution. This allows the solvent to permeate the separation functional layer appropriately, shortening the evaluation time, and the detection accuracy is good because the original concentration is high. The concentration of the induction solute may more preferably be 1% by mass or more and 10% by mass or less, and even more preferably 1% by mass or more and 5% by mass or less.

[0032] The inducing solute contained in the inducing solution is preferably at least one selected from inorganic salts and hydrophilic organic compounds. Examples of inorganic salts include alkali metal salts, alkaline earth metal salts, and ammonium salts. Examples of hydrophilic organic compounds include sugars, monoalcohols, glycols, and water-soluble polymers.

[0033] Examples of alkali metal salts include sodium chloride, potassium chloride, sodium sulfate, sodium thiosulfate, and sodium sulfite. Examples of alkaline earth metal salts include magnesium chloride, calcium chloride, and magnesium sulfate. Examples of ammonium salts include ammonium chloride, ammonium sulfate, and ammonium carbonate. Examples of sugars include common sugars such as sucrose, fructose, and glucose, as well as special sugars such as oligosaccharides and rare sugars. Examples of monoalcohols include methanol, ethanol, 1-propanol, and 2-propanol. Examples of glycols include ethylene glycol and propylene glycol. Examples of water-soluble polymers include polyethylene oxide and polypropylene oxide, as well as copolymers of ethylene oxide and propylene oxide. From the viewpoint of allowing the solvent to permeate the separation functional layer appropriately and shortening the evaluation time, the number-average molecular weight of the induced solute is preferably 20 to 300. Furthermore, from the viewpoint of being easily detectable by conductivity and / or refractive index, it is also preferable that the induced solute includes a monovalent salt. In a similar view, the derivative solute may also preferably include an alcohol having 1 to 4 carbon atoms and / or acetonitrile.

[0034] <Adjustment process> The evaluation method for a forward osmosis membrane module according to this disclosure may include an adjustment step before the connection step, in which the physical parameters of the raw material liquid and / or induction solution supplied to the forward osmosis membrane module are adjusted. Examples of physical parameters include the physical pressure, temperature, and flow rate of the raw material liquid and / or induction solution. The adjustment step is preferred because it shortens the evaluation time and allows for more accurate evaluation results.

[0035] The method of this disclosure preferably further includes, for example, a step of adjusting the physical pressure of the induction solution to greater than 0 kPa and less than or equal to 200 kPa while circulating the induction solution outside the forward osmosis membrane module before the connection step. By adjusting the physical pressure of the induction solution in advance before connecting the induction solution line to the forward osmosis membrane module, the evaluation results of the forward osmosis membrane module become more stable and can be evaluated accurately in a shorter time. From the viewpoint of evaluating accurately in a shorter time, the physical pressure of the induction solution is preferably adjusted to 5 kPa to 200 kPa, more preferably 10 kPa to 200 kPa, even more preferably 15 kPa to 150 kPa, and particularly preferably 20 kPa to 100 kPa before the connection step.

[0036] The method of this disclosure preferably further includes, for example, a step of adjusting the temperature difference between the raw material solution and the induced solution to within 10°C before the connection step. The temperature difference is more preferably within 5°C, even more preferably within 3°C, and even more preferably within 1°C. By adjusting the temperature difference between the raw material solution and the induced solution to be small in advance before the connection step, individual differences such as how easily the raw material solution and the induced solution cool or heat up due to the forward osmosis membrane module can be taken into account, and the values ​​of water permeability and salt back diffusion can be stabilized because the osmotic pressure of the raw material solution and the induced solution can be maintained more constantly, resulting in more stable evaluation results for the forward osmosis membrane module and enabling more accurate evaluation in a shorter time. The temperature adjustment of the raw material solution can be performed while circulating the raw material solution outside the forward osmosis membrane module. Similarly, the temperature adjustment of the induced solution can be performed while circulating the induced solution outside the forward osmosis membrane module. The temperatures of the raw material solution and the induced solution may be the ambient temperature, for example, around 25±5°C.

[0037] The method of this disclosure preferably further includes, for example, a step of adjusting the flow rates of the raw material solution and the induction solution before the connection step. In the flow rate adjustment step, it is preferable to adjust the flow rates of the raw material solution and the induction solution in advance before the connection step so that the difference between the residence time of the raw material solution in the space on the separation functional layer side and the residence time of the induction solution in the space on the porous support side is within 20 seconds after the connection of the forward osmosis membrane module. The difference in residence time is more preferably adjusted to be within 15 seconds, even more preferably 10 seconds, even more preferably 5 seconds, and particularly preferably within 1 second. By adjusting the flow rates in advance before connection, taking into account the residence time after connection, individual differences in forward osmosis membrane modules can be taken into account, the evaluation results of the forward osmosis membrane module become more stable, and evaluation can be performed accurately in a shorter time. In addition, by reducing the difference in residence time, it is easier to control the concentration rate of the raw material solution and the dilution rate of the induction solution within the forward osmosis membrane module, and the evaluation results can be made more stable. The flow rate adjustment of the raw material solution can be performed while circulating the raw material solution outside the forward osmosis membrane module, and the flow rate adjustment of the induction solution can also be performed while circulating the induction solution outside the forward osmosis membrane module. The residence time of the raw material solution is preferably 1 to 10 seconds, more preferably 1 to 5 seconds. The residence time of the induction solution is also preferably 1 to 10 seconds, more preferably 1 to 5 seconds. When the residence times of the raw material solution and induction solution are within this range, excessive concentration of the raw material solution and dilution of the induction solution do not occur, and the performance of the forward osmosis membrane can be evaluated more accurately across the entire forward osmosis membrane module.

[0038] In the flow rate adjustment process, it is also preferable to adjust the flow rates of the raw material liquid and the induction solution in advance before the connection process so that the difference between the linear velocity of the raw material liquid in the separation functional layer space and the linear velocity of the induction solution in the porous support space is within 10 cm / sec after the connection of the forward osmosis membrane module. The difference in linear velocity is more preferably adjusted to within 5 cm / sec, and even more preferably within 1 cm / sec. By adjusting the flow rates in advance before connection, taking into account the linear velocity after connection, individual differences in the forward osmosis membrane module can be taken into account, resulting in more stable evaluation results for the forward osmosis membrane module and enabling more accurate evaluation in a shorter time. The linear velocity of the raw material liquid may preferably be around 1 cm / sec to 10 cm / sec, more preferably around 1 cm / sec to 5 cm / sec. The linear velocity of the induction solution may also preferably be around 1 cm / sec to 10 cm / sec, more preferably around 1 cm / sec to 5 cm / sec. Here, linear velocity refers to the linear velocity at the surface of the forward osmosis membrane. Depending on the configuration of the forward osmosis membrane module, the residence time can also be adjusted by adjusting the linear velocity.

[0039] The flow rate can be adjusted before the connection process based on the cross-sectional areas of the raw material supply section and the induction solution supply section within the forward osmosis membrane module being used. The raw material supply section and the induction solution supply section refer to the space through which the raw material flows and the space through which the induction solution flows, respectively, within the portion of the forward osmosis membrane module that functions as a forward osmosis membrane (effective membrane area). The cross-sectional area is the cross-sectional area perpendicular to the direction in which the raw material and induction solutions flow. For example, in the case of a hollow fiber membrane module with a separation functional layer on its inner surface, the portion filled with hollow fiber bundles that functions as a forward osmosis membrane is the effective membrane area, and within this, the raw material supply section corresponds to the inside of the hollow fibers (separation functional layer side), and the induction solution supply section corresponds to the outside of the hollow fibers. In the case of a complex structure where the cross-sectional area changes depending on the position of the cross-section, the calculation should be performed using the portion within the forward osmosis membrane module that has the largest proportion of the same cross-sectional area within the effective membrane area. Examples of forward osmosis membrane modules other than hollow fiber membrane modules include plate-type modules and spiral-type modules, but the same concept can be used to adjust the flow rate based on the cross-sectional area.

[0040] Even if the cross-sectional area of ​​the forward osmosis membrane module is unknown, a preliminary experiment can be conducted by flowing water through the forward osmosis membrane module, instantaneously adding a dye (for example, brilliant blue), and measuring the time it takes for the dye to be discharged. This allows for the understanding of the relationship between flow rate and residence time. Based on the relationship between flow rate and residence time in both the raw material supply section and the induction solution supply section, the flow rate can be adjusted.

[0041] The method of this disclosure preferably includes adjusting at least one physical parameter selected from the group consisting of adjusting physical pressure, adjusting temperature, and adjusting flow rate, prior to the connection step. The adjustment of the physical parameter may be pre-controlled prior to the connection step based on information about the forward osmosis membrane module, the raw material, and the induction solution used. The physical parameter may be pre-controlled prior to the connection step, for example, by determining the pressure and flow rate of the induction solution based on information about the cross-sectional area of ​​the raw material supply section and the induction solution supply section in the forward osmosis membrane module, a desired physical pressure difference, and a desired minimum flow rate of the raw material. This makes the evaluation results of the forward osmosis membrane module more stable and allows for more accurate evaluation in a shorter time.

[0042] <Connection Process> The evaluation method for a forward osmosis membrane module according to this disclosure includes the step of connecting the space on the separation functional layer side of the forward osmosis membrane module to a raw material liquid line and the space on the porous support side to an induction solution line. This allows the raw material liquid to be delivered to the space on the separation functional layer side of the forward osmosis membrane module and the induction solution to be delivered to the space on the porous support side. Preferably, the raw material liquid line is connected so that the raw material liquid can be recovered from the forward osmosis membrane module and circulated, and preferably, the induction solution line is connected so that the induction solution can be recovered from the forward osmosis membrane module and circulated. The connection between the raw material liquid line and the induction solution line can be made so that the raw material liquid and induction solution flow countercurrently or in parallel. When connected in parallel flow, the raw material liquid and induction solution come into contact with each other immediately after evaluation via the forward osmosis membrane, so the evaluation start time is earlier, and in the case of an apparatus in which the hollow fiber membrane module is installed vertically, air bubbles in the module can be easily removed, so it is preferable to be able to evaluate accurately in a shorter time. Note that installing the hollow fiber membrane module vertically is advantageous in that the size of the apparatus is reduced. On the other hand, when connecting in a countercurrent manner, it is preferable because a high osmotic pressure difference can be maintained throughout the module by having the concentrated raw material solution and the undiluted derivative solution come into contact within the module, and by having the unconcentrated raw material solution and the diluted derivative solution come into contact.

[0043] <Evaluation Process> In the evaluation process, the raw material liquid and the induced solution are first flowed countercurrently or parallel to each other through a forward osmosis membrane. The order in which the raw material liquid and the induced solution are supplied to the forward osmosis membrane module is flexible; either the raw material liquid or the induced solution may be supplied first, or both may be supplied simultaneously. In the method disclosed herein, in a forward osmosis evaluation where the raw material liquid is supplied to the separation functional layer side of the forward osmosis membrane, if the solvent of the raw material liquid is water, it is preferable to supply the induced solution after supplying the raw material liquid to the forward osmosis membrane module. Since water has no osmotic pressure, even if it is supplied to the forward osmosis membrane module before the induced solution, air bubbles are less likely to be mixed into the forward osmosis membrane, especially in the thickness of the support membrane of the forward osmosis membrane (so-called airlock), allowing for simpler and more accurate evaluation. Furthermore, by supplying water first as the raw material liquid, air bubbles in the raw material liquid passage portion within the forward osmosis membrane module can be removed without adversely affecting the evaluation results, allowing for accurate evaluation of water permeability and salt back diffusion from the initial stages of evaluation.

[0044] In the evaluation process, the solvent in the raw material liquid is moved into the induction solution while the physical pressure difference between the forward osmosis membranes is kept constant within a range greater than 0 kPa and less than or equal to 200 kPa, with the porous support side being the positive side. By keeping the physical pressure difference below 200 kPa, the membrane of the forward osmosis membrane module is less likely to be damaged unnecessarily, and by keeping it greater than 0 kPa, the influence of physical pressure that occurs in the direction of peeling the separation functional layer from the porous support during actual use of the forward osmosis membrane module can be appropriately considered. Therefore, the method disclosed herein can accurately evaluate the practical performance of a forward osmosis membrane including a support membrane and a separation functional layer.

[0045] From the viewpoint of more accurate evaluation, the physical pressure difference is preferably 5kPa to 200kPa, more preferably 10kPa to 200kPa, even more preferably 15kPa to 150kPa, and particularly preferably 20kPa to 100kPa, with the porous support side being positive. However, from the viewpoint of moving the solvent in the raw material liquid into the induction solution, the physical pressure difference can be less than or equal to the osmotic pressure difference between the raw material liquid and the induction solution. It is preferable to monitor and maintain the physical pressure difference in real time, and it is more preferable to maintain the real-time physical pressure difference within ±1kPa of the desired physical pressure difference. By maintaining the physical pressure difference within the above range, the diffusivity of the induction solution within the porous support of the forward osmosis membrane is promoted, the renewal of the induction solution near the separation functional layer is further promoted, and the decrease in water permeability due to pressurization from the induction solution side can be kept below a certain level, so that the variation in evaluation results (water permeability and salt back diffusion amount) is small and the practical performance can be made accurate.

[0046] In the evaluation process, the temperature difference between the raw material solution and the derived solution is preferably adjusted to within 10°C. More preferably, the temperature difference is within 5°C, even more preferably within 3°C, and even more preferably within 1°C. By adjusting the temperature difference to be small, the evaluation results of the forward osmosis membrane module become more stable and can be evaluated with greater accuracy. The temperatures of the raw material solution and the derived solution may be the ambient temperature, for example, around 25±5°C.

[0047] In the evaluation process, it is preferable to adjust the flow rates of the raw material liquid and the induction solution so that the difference between the residence time of the raw material liquid in the space on the separation functional layer side and the residence time of the induction solution in the space on the porous support side is within 20 seconds. The difference in residence time is more preferably adjusted to within 15 seconds, even more preferably 10 seconds, even more preferably 5 seconds, and particularly preferably within 1 second. By adjusting the difference in residence time to be small, the evaluation results of the forward osmosis membrane module become more stable and can be evaluated with greater accuracy. The residence time of the raw material liquid may preferably be around 1 to 10 seconds, more preferably around 1 to 5 seconds. The residence time of the induction solution may also preferably be around 1 to 10 seconds, more preferably around 1 to 5 seconds.

[0048] In the evaluation process, it is preferable to adjust the flow rates of the raw material solution and the induction solution so that the difference between the linear velocity of the raw material solution in the space on the separation functional layer side and the linear velocity of the induction solution in the space on the porous support side is within 10 cm / sec. More preferably, the difference in linear velocity is adjusted to within 5 cm / sec, and even more preferably within 1 cm / sec. By adjusting the difference in linear velocity to be small, the evaluation results of the forward osmosis membrane module become more stable and can be evaluated with greater accuracy. The linear velocity of the raw material solution may preferably be around 1 cm / sec to 10 cm / sec, more preferably around 1 cm / sec to 5 cm / sec. The linear velocity of the induction solution may also preferably be around 1 cm / sec to 10 cm / sec, more preferably around 1 cm / sec to 5 cm / sec. By setting the linear velocity to a moderate level, damage to the membrane itself caused by the evaluation is suppressed. By setting the linear velocity to a moderate level, excessive concentration of the raw material solution and excessive dilution of the induction solution due to the stagnation of each solution in the forward osmosis membrane module are suppressed, making it easier to evaluate under constant conditions, and as a result, the evaluation results tend to be more stable.

[0049] In the evaluation process, the solution containing the raw material after it has been supplied to and exited the forward osmosis membrane module (hereinafter referred to as "post-supply raw material") may be in a circulating system that returns directly to the raw material tank, indirectly returned to the raw material tank after other processing, or in a one-pass system that does not return to the raw material tank. In the case of a circulating system, the amount of back diffusion of the induced solute can be managed and evaluated in one raw material tank during one evaluation of one forward osmosis membrane module, thus enabling more accurate evaluation of the amount of salt back diffusion in the forward osmosis membrane module. In the case of indirect return, for example, the post-supply raw material containing a small amount of salt may be desalted and finally returned to the raw material tank. In the case of a one-pass system, it is possible to simultaneously supply liquid to multiple modules from one raw material tank, and since the induced solute does not mix into the raw material tank after the forward osmosis evaluation (the raw material tank is not contaminated), the time required for multiple evaluations can be reduced.

[0050] In a one-pass system, the performance of the forward osmosis membrane can be easily evaluated without contaminating the raw material tank by measuring the difference in at least one parameter selected from conductivity, refractive index, total organic carbon (TOC), chemical oxygen demand (COD), biochemical oxygen demand (BOD), absorbance, and transmittance between the raw material liquid and the supplied raw material liquid, and comparing this parameter with the induced solution. For example, by measuring the difference in conductivity between the inlet and outlet sides of the forward osmosis membrane module over time, it is possible to estimate how much salt has moved in a one-pass system. By measuring the differences in total organic carbon (TOC), chemical oxygen demand (COD), and biochemical oxygen demand (BOD) over time, it is possible to estimate how much organic matter has moved in a one-pass system. By measuring the difference in absorbance over time, it is possible to estimate how much absorbent substance (e.g., dyes, aromatic compounds, compounds with conjugated bonds) has moved in a one-pass system. By measuring the difference in transmittance over time, it is possible to estimate how much fine particles or crystalline material has moved in a single-pass system. The single-pass system is preferred in at least one evaluation selected from the group consisting of conductivity, refractive index, and absorbance, from the viewpoint of ease of evaluation and low variability. These measurements may be used individually, or multiple measurements may be used in combination from the viewpoint of improving evaluation accuracy. The measurement of the physical properties of the raw material after supply, as described above, may be performed at any stage after it has left the forward osmosis membrane module. For example, the raw material after supply discharged in a single-pass system may be collected in a tank separate from the raw material tank, and the physical properties of the collected raw material may be measured directly.

[0051] In the case of a one-pass type, it is preferable to start the evaluation 10 seconds or more after the raw material liquid has been supplied to the forward osmosis membrane module and has left the module. More specifically, it is preferable to set the point at which the raw material liquid begins to be discharged from the forward osmosis membrane module as 0 seconds, and to continue discharging the supplied raw material liquid for 10 seconds and not use it for evaluation. In other words, it is preferable not to use the evaluation for at least 10 seconds as a stabilization time to stabilize the evaluation results, and to use the measured values ​​thereafter for evaluation. If there is a stabilization time, it is possible to evaluate while avoiding fluctuations in the properties of the supplied raw material liquid, which can be seen in the initial stages of the forward osmosis membrane, especially in the one-pass method, and thus enable accurate evaluation. The stabilization time is preferably 30 seconds or more, more preferably 1 minute or more, preferably 30 minutes or less, more preferably 20 minutes or less, even more preferably 10 minutes or less, and even more preferably 5 minutes or less from the viewpoint of shortening the evaluation time.

[0052] The evaluation process may involve monitoring and maintaining in real time at least one physical parameter selected from the group consisting of the physical pressure difference, temperature, flow rate, minimum flow rate, conductivity, and refractive index of the raw material liquid and the derived solution. For example, it is preferable to monitor in real time the physical pressure difference, flow rate, and minimum flow rate of the raw material liquid and the derived solution and maintain a flow rate above the desired physical pressure difference and minimum flow rate of the raw material liquid and the derived solution. This stabilizes each physical parameter, reduces hunting, and enables more accurate evaluation. Control is preferably performed using a proportional-integral-derivative (PDI) control algorithm because it reduces hunting and enables more accurate evaluation.

[0053] The performance of a forward osmosis membrane module that can be evaluated by the evaluation method for forward osmosis membrane modules in this disclosure includes, for example, the salt reverse diffusion rate (RSF) (g / m³). 2 ×hr)), water permeability (Flux)(kg / (m 2 Examples include salt permeability (RSF / Flux) (g / kg), calculated by dividing RSF by Flux.

[0054] RSF refers to the amount of induced solute that moves from the induced solution to the raw material when the raw material to be concentrated is flowed through a forward osmosis membrane on the separation function layer side and an induction solution with a higher osmotic pressure is placed on the support membrane side. RSF is defined by the following equation (1). RSF = G / (M×H)...Equation (1) In the formula, G is the amount of induced solute transferred (g), and M is the effective membrane area of ​​the forward osmosis membrane (m²). 2 ) and H is time (hr). Here, the effective membrane area is the membrane area on the side with the separation functional layer. A lower RSF is preferable. If the RSF is too high, problems such as the induction solute in the induction solution mixing with the raw material solution, or the solute in the raw material solution mixing with the induction solution, a decrease in the purity of the raw material concentrate and an imbalance of components, contamination of the induction solution, and a decrease in components in the induction solution over time will occur.

[0055] Flux refers to the amount of solvent (mainly water) that moves from the raw material solution to the induction solution when a raw material solution to be concentrated is flowed through the separation functional layer side of a forward osmosis membrane, and an induction solution with a higher osmotic pressure is placed on the support membrane side. Flux is defined by the following equation (2). Flux = L / (M×H)...Equation (2) In the formula, L is the amount of solvent that has permeated (kg), and M is the effective surface area of ​​the forward osmosis membrane (m²). 2 ) and H is time (hr). Here, the effective membrane area is the membrane area on the side with the separation functional layer. A higher Flux is preferable in order to achieve highly efficient solvent transfer.

[0056] RSF / Flux is an index that represents the selectivity of solvent permeation and salt permeation. A lower RSF / Flux is preferable because it makes it more difficult for salts to permeate and easier for solvents to permeate.

[0057] The evaluation method for forward osmosis membrane modules described herein allows for evaluation of the performance of the forward osmosis membrane, taking into account its physical durability, by performing forward osmosis evaluation while creating a physical pressure difference between the membranes. If the physical durability of the forward osmosis membrane is low, it may not be able to withstand this physical pressure difference, causing a portion of the separation functional layer to peel off from the porous support and crack in the separation functional layer, resulting in irreversible deterioration. This makes it easier for the induction solution to permeate to the raw material liquid side, and the RSF and RSF / Flux values ​​become significantly larger compared to evaluation with a physical pressure difference of 0 kPa. Even if the forward osmosis membrane has sufficient physical durability and does not undergo irreversible deterioration, the physical pressure from the induction solution side generally makes it easier for the induction solution to permeate, often resulting in larger RSF and RSF / Flux values ​​compared to evaluation with a physical pressure difference of 0 kPa. Therefore, the method described herein can accurately evaluate the RSF and RSF / Flux values ​​in actual use.

[0058] Evaluation equipment for forward osmosis membrane modules The evaluation apparatus for a forward osmosis membrane module according to this disclosure comprises a raw material liquid tank, a raw material liquid line, a raw material liquid supply means, an induction solution tank, an induction solution line, an induction solution supply means, a pressure adjustment means installed on the induction solution line, and a pressure sensor installed on the induction solution line. The forward osmosis membrane module to be evaluated is a forward osmosis membrane module having a forward osmosis membrane, preferably a forward osmosis membrane module having a forward osmosis membrane having a support membrane with a porous support and a separation functional layer provided on the porous support. The forward osmosis membrane module is more preferably a hollow fiber membrane module. For details on the forward osmosis membrane module, please refer to the section on "Forward Osmosis Membrane Module" in the above-mentioned "Evaluation Method for a Forward Osmosis Membrane Module".

[0059] <Raw material liquid tank and induction solution tank> The raw material tank contains the raw material, and the induction solution tank contains the induction solution. The raw material tank and / or induction solution tank may be equipped with a stirrer. Preferably, the raw material tank or the induction solution tank, or both, are equipped with temperature control means that can adjust the temperature of the raw material or the induction solution. By equipping the raw material tank and / or induction solution tank with temperature control means, individual differences in how easily the raw material and induction solution cool or heat up due to the forward osmosis membrane module can be taken into account, resulting in more stable evaluation results for the forward osmosis membrane module and enabling more accurate evaluation in a shorter time.

[0060] Preferably, the raw material liquid tank or the induction solution tank, or both, further comprises at least one selected from the group consisting of a temperature sensor, a conductivity sensor, and a refractive index sensor, each capable of measuring the temperature, conductivity, or refractive index of the raw material liquid or induction solution. The inclusion of these sensors in the raw material liquid tank and / or induction solution tank makes it easier to compare and control each measurement in real time.

[0061] <Raw material liquid line> The raw material liquid line connects the raw material liquid tank to the forward osmosis membrane module, and is configured to supply the raw material liquid from the raw material liquid tank to the forward osmosis membrane module through the raw material liquid line using a raw material liquid supply means. The raw material liquid supply means may be, for example, a pump (hereinafter also referred to as the "raw material liquid supply pump"). Preferably, the raw material liquid line is further configured to recover the raw material liquid from the forward osmosis membrane module, return it to the raw material liquid tank, and supply it again to the forward osmosis membrane module (circulation).

[0062] The raw material liquid line has a circulation structure that allows the raw material liquid to be circulated outside the forward osmosis membrane module before being connected to the forward osmosis membrane module, and may also include a raw material liquid bypass line that forms part of the circulation structure of the raw material liquid line and can be attached to and detached from the forward osmosis membrane module. A bypass line is a line that allows each liquid to be circulated without passing through the forward osmosis membrane module. By having a circulation structure outside the forward osmosis membrane module in the raw material liquid line, it is easier to adjust physical parameters such as the physical pressure, temperature, and flow rate of the raw material liquid before connecting it to the forward osmosis membrane module. In addition, by having a raw material liquid bypass line, the flow of raw material liquid with adjusted physical parameters can be connected to the forward osmosis membrane module, enabling faster and more accurate evaluation. The bypass line only needs to have a structure that allows the solution to be circulated outside the forward osmosis membrane module. For example, by branching the forward osmosis membrane module and the bypass line and connecting them in parallel, the solution can be circulated outside the forward osmosis membrane module through the bypass line while the forward osmosis membrane module side is sealed with a valve or the like to prevent the solution from flowing. After circulating the solution through the bypass line, the solution can be supplied to the forward osmosis membrane module by sealing the bypass line side and opening the forward osmosis membrane module side.

[0063] The raw material liquid line is preferably equipped with pressure regulating means installed on the raw material liquid line. The pressure regulating means on the raw material liquid line can assist in adjusting the physical pressure difference between the raw material liquid and the induced solution to a constant range greater than 0 kPa and less than or equal to 200 kPa via the forward osmosis membrane. It is more preferable that the raw material liquid line has a circulating structure so that the pressure regulating means is configured to adjust the physical pressure of the raw material liquid before, during, and after evaluation of the forward osmosis membrane module. Examples of pressure regulating means include valves (also called "pressure regulating valves"), back pressure valves, pressurization by pumps, and combinations thereof.

[0064] The raw material liquid line is preferably equipped with a temperature control means installed on the raw material liquid line. The temperature control means on the raw material liquid line can help adjust the temperature difference between the raw material liquid and the induction solution to within 10°C. It is even more preferable that the raw material liquid line has a circulating structure so that the temperature control means can adjust the temperature of the raw material liquid before, during, and after evaluation of the forward osmosis membrane module. Examples of temperature control means include double-tube heat exchangers, temperature-controlled chillers, and heaters.

[0065] The raw material liquid line preferably further comprises at least one selected from the group consisting of pressure sensors, temperature sensors, flow rate sensors, conductivity sensors, and refractive index sensors, which are installed on the raw material liquid line and capable of measuring the physical pressure, temperature, flow rate, conductivity, or refractive index of the raw material liquid. Having these sensors in the raw material liquid line makes it easier to control each physical parameter of the raw material liquid, thus enabling faster and more accurate evaluation. These sensors may be placed before or after the forward osmosis membrane module, or both.

[0066] <Induction Solution Line> The induction solution line connects the induction solution tank to the forward osmosis membrane module, and is configured to supply the induction solution from the induction solution tank to the forward osmosis membrane module through the induction solution line using an induction solution supply means. The induction solution supply means may be, for example, a pump (hereinafter also referred to as the "induction solution supply pump"). Preferably, the induction solution line is further configured to recover the induction solution from the forward osmosis membrane module, return it to the induction solution tank, and supply it again to the forward osmosis membrane module (circulation).

[0067] The induction solution line preferably has a circulation structure that allows the induction solution to be circulated outside the forward osmosis membrane module before being connected to the forward osmosis membrane module, and more preferably includes an induction solution bypass line that forms part of the circulation structure of the induction solution line and can be attached to and detached from the forward osmosis membrane module. Having a circulation structure outside the forward osmosis membrane module makes it easier to adjust the physical parameters of the induction solution, such as physical pressure, temperature, and flow rate, before connecting it to the forward osmosis membrane module. Furthermore, having an induction solution bypass line allows the flow of the induction solution with adjusted physical parameters to be connected to the forward osmosis membrane module, enabling faster and more accurate evaluation. Other advantages are the same as those of the raw material bypass line.

[0068] The induction solution line is equipped with pressure adjustment means installed on the induction solution line that can physically pressurize the induction solution before, during, and after evaluation of the forward osmosis membrane module. The pressure adjustment means is configured to maintain a constant physical pressure difference between the induction solution and the physical pressure of the raw material via the forward osmosis membrane, within a range greater than 0 kPa and less than or equal to 200 kPa. The induction solution line further includes a pressure sensor installed on the induction solution line that can measure the physical pressure of the induction solution. This makes it easier to maintain a constant physical pressure difference. Examples of pressure adjustment means include valves (also called "pressure adjustment valves"), pressurization by pumps, and combinations thereof.

[0069] The induction solution line is preferably equipped with a temperature control means installed on the induction solution line. The temperature control means on the induction solution line can help adjust the temperature difference between the raw material liquid and the induction solution to within 10°C. It is more preferable that the induction solution line has a circulating structure so that the temperature control means can adjust the temperature of the induction solution before, during, and after evaluation of the forward osmosis membrane module. Examples of temperature control means include double-tube heat exchangers, temperature-controlled chillers, and heaters.

[0070] The induction solution line preferably further includes at least one selected from the group consisting of a temperature sensor, a flow sensor, a conductivity sensor, and a refractive index sensor, which can measure the temperature, flow rate, conductivity, or refractive index of the induction solution. Having these sensors in the induction solution line makes it easier to control each physical parameter of the induction solution, thus enabling faster and more accurate evaluation. These sensors may be positioned before or after the forward osmosis membrane module, or both.

[0071] The induction solution line and / or induction solution tank preferably further comprises concentration adjustment means capable of removing the solvent from the induction solution, adding a high-concentration induction solution to the induction solution, or adding an induction solute. If the induction solution line and / or induction solution tank has a circulation structure, the concentration of the circulating induction solution can be efficiently regenerated by providing the concentration adjustment means in the induction solution line, thereby enabling more accurate evaluation. As a means of removing the solvent from the induction solution, for example, an evaporation means that removes the solvent from the induction solution by evaporating it. The evaporation means is preferably a means other than membrane distillation, and may be, for example, a distillation process, a vacuum distillation process, a natural drying process, etc. The concentration of the induction solute in the high-concentration induction solution only needs to be higher than the concentration in the induction solution diluted by passing through the forward osmosis membrane module, and may be a saturated solution. As a method of adding a high-concentration induction solution or an induction solute to the induction solution, a solution containing the same or a different solute as the induction solute may be added. For example, if the induction solute is NaCl, a method of adding a few drops of a saturated solution of NaCl as the same solute may be used. Alternatively, if a 1% by mass aqueous solution of NaCl is the induction solution, a method can be used to add a different solute, such as a 10% by mass induction solution of MgCl2, which has a higher osmotic pressure than NaCl depending on the concentration. In this disclosure, it is preferable to control the concentration by adding a high-concentration induction solution with the same induction solute, as this facilitates the analysis of evaluation results and enables highly accurate measurement in a shorter time. Means for adding a high-concentration induction solution include, for example, adding it directly to the tank, and transferring it from the tank to a separate system by pump, concentrating it by evaporation, and then returning it to the tank.

[0072] The evaluation apparatus of this disclosure only needs to have at least one set of raw material liquid line and induction solution line, preferably multiple sets, so that multiple forward osmosis membrane modules can be evaluated in parallel. When multiple sets of raw material liquid line and induction solution line are provided, the evaluation efficiency is dramatically improved, and it is easy to extract the forward osmosis membrane module with inferior performance from a group of multiple forward osmosis membrane modules.

[0073] <Control device> The evaluation apparatus of this disclosure is preferably configured to monitor the measured values ​​and times in real time using each sensor, including a pressure sensor installed on the induction solution line, and to store them in a database, so that the difference between the values ​​of the raw material liquid, the induction solution, or both during solution circulation before evaluation and the values ​​at the time of evaluation of the forward osmosis membrane module can be detected. This allows for real-time monitoring and maintenance of the physical parameters of the raw material liquid and the induction solution, as described later, thus enabling more accurate evaluation.

[0074] The evaluation apparatus of the present disclosure may further include a control device, which may be configured to monitor and maintain in real time at least one physical parameter selected from the group consisting of the physical pressure difference, temperature, flow rate, minimum flow rate, conductivity, and refractive index of the raw material liquid and the induced solution. For example, if the raw material liquid line is provided with pressure adjustment means, a pressure sensor, and a flow rate sensor, and the induced solution line is further provided with a flow rate sensor, the evaluation apparatus may further include a control device coupled to the respective pressure sensor, flow rate sensor, and pressure adjustment means on the raw material liquid line and the induced solution line, as well as to the raw material liquid supply means and the induced solution supply means. Preferably, the control device is configured to compare the physical pressure difference, flow rate, and minimum flow rate of the raw material liquid and the induced solution in real time. Furthermore, preferably, the control device is configured to control the respective pressure adjustment means, raw material liquid supply means, and induced solution supply means so as to maintain a desired physical pressure difference and a flow rate above the minimum flow rate of the raw material liquid and the induced solution. This stabilizes each physical parameter, reduces hunting, and enables more accurate evaluation.

[0075] When physical pressure differences are compared in real time, it is preferable that the control device is configured to maintain the real-time physical pressure difference within ±1 kPa of the desired physical pressure difference.

[0076] The control device may be configured to control at least one of the physical parameters of the raw material solution and the induced solution, such as physical pressure, temperature, and flow rate, based on input of information about the forward osmosis membrane module, raw material solution, and induced solution used. For example, it is preferable that the control device be configured to determine and pre-control the pressure and flow rate of the induced solution before evaluating the forward osmosis membrane module by inputting information on the cross-sectional area of ​​the raw material solution supply section and the induced solution supply section in the forward osmosis membrane module, a desired physical pressure difference, and a desired minimum flow rate of the raw material solution. This stabilizes each physical parameter, reduces hunting, and enables more accurate evaluation.

[0077] When controlling physical parameters such as physical pressure differences in real time, the control device preferably includes a processor configured to execute a proportional-integral-derivative (PID) control algorithm. This ensures that each physical parameter is stable, reduces hunting, and allows for more accurate evaluation. PID control is a type of feedback control in control engineering, and it is a control method that controls input values ​​using three elements: the deviation between the output value and the target value, its integral, and its derivative. For example, the physical pressure difference, flow rate, and minimum flow rate of the raw material liquid and the induced solution may be monitored in real time (output values), and the control device may be configured to control the manipulated variables (input values) of the respective pressure adjustment means, raw material liquid supply means, and induced solution supply means based on the deviation between the desired physical pressure difference and the desired flow rate (target value) above the minimum flow rate, its integral, and its derivative.

[0078] Examples of evaluation methods and equipment for forward osmosis membrane modules. Figure 1 is a schematic diagram of a cross-section of a forward osmosis membrane in the evaluation method of the present disclosure. As schematically shown in Figure 1, for example, in a forward osmosis membrane (11) consisting of a porous support (11a) and a separation functional layer (11b), the induction solution is supplied to the space (10a) on the porous support (11a) side and the raw material liquid is supplied to the space (10b) on the separation functional layer (11b) side. The direction of the dotted arrow indicates the flow direction of the induction solution, and the direction of the solid arrow indicates the flow direction of the raw material liquid. In Figure 1, the induction solution is depicted as flowing parallel to the raw material liquid, but it may also be flowing convect (countercurrent). The induction solution and the raw material liquid are in contact via the forward osmosis membrane (11), and an osmotic pressure difference is generated. Based on the osmotic pressure difference, the solvent moves from the raw material liquid to the induction solution in the solvent movement direction (P1). On the other hand, the performance of the forward osmosis membrane module is evaluated while constantly adjusting the physical pressure difference between the induction solution and the raw material liquid to be greater than 0 kPa and within a range of 200 kPa or less, with the direction of physical pressure application (P2), i.e., with the porous support side as positive (high pressure).

[0079] Figure 2 is a schematic diagram showing an example of an evaluation method for a forward osmosis membrane module using the evaluation apparatus of the present disclosure. In Figure 2, the forward osmosis membrane module (10) has a forward osmosis membrane (11) consisting of a porous support and a separation functional layer (not shown), and the space within the forward osmosis membrane module is separated by the forward osmosis membrane into a space on the porous support side (10a) and a space on the separation functional layer side (10b). A raw material liquid line (20) and an induction solution line (30) are prepared. The raw material liquid line (20) is equipped with a raw material liquid supply pump (22) as a raw material liquid supply means for sending the raw material liquid from a raw material liquid tank (21) to the forward osmosis membrane module. The raw material liquid line (20) is fluidly connected to the space on the separation functional layer side (10b) and is configured to recover the raw material liquid from the forward osmosis membrane module and return it to the raw material liquid tank for circulation. The induction solution line (30) includes an induction solution supply pump (32) as an induction solution supply means for delivering the induction solution from the induction solution tank (31) to the forward osmosis membrane module. The induction solution line (30) is fluidly connected to the space (10a) on the porous support side and is configured to recover the induction solution from the forward osmosis membrane module, return it to the induction solution tank, and circulate it. The induction solution line (30) also includes a pressure adjustment valve (33) as a pressure adjustment means for adjusting the physical pressure of the induction solution and a pressure sensor (34) for measuring the physical pressure of the induction solution on the line that recovers the induction solution from the forward osmosis membrane module. The pressure adjustment valve (33) and pressure sensor (34) are connected to a control device (not shown) and are configured to compare the physical pressure difference between the raw material liquid and the induction solution in real time and adjust the physical pressure difference to be constant within a range greater than 0 kPa and less than or equal to 200 kPa, with the porous support side being positive.

[0080] Figure 3 is a schematic diagram showing an example of a hollow fiber membrane module. In Figure 3, the forward osmosis membrane module (10) is a hollow fiber membrane module comprising a bundle of hollow fibers composed of a forward osmosis membrane (11). The hollow fibers of the forward osmosis membrane (11) have a porous support on the outside (corresponding to 11a in Figure 1) and a separation functional layer on the inside (corresponding to 11b in Figure 1). The bundle of hollow fibers is filled into a cylindrical module housing, and both ends of the bundle of hollow fibers are fixed within the module housing by adhesive fixing parts (14). However, the adhesive fixing parts (14) are solidified so as not to block the holes at both ends of the hollow fibers. As a result, the space within the module housing is separated into a space on the porous support (11a) side (10a) and a space on the separation functional layer (11b) side (10b). The module housing further has an inner conduit (12) at both ends that communicates with the inside of the hollow fiber (i.e., the space on the separation function layer side (10b)), and an outer conduit (13) on its side that communicates with the outside of the hollow fiber (i.e., the space on the porous support side (10a)). The raw material liquid can be introduced into the space on the separation function layer side (10b) and withdrawn from the space on the separation function layer side (10b) through the inner conduit (12). The induction solution can be introduced into the space on the porous support side (10a) and withdrawn from the space on the porous support side (10a) through the outer conduit (13). The raw material liquid flowing inside the hollow fiber and the induction solution flowing outside can only come into contact through the hollow fiber membrane. The hollow fiber membrane module has an effective membrane area portion (15) that is responsible for the separation function. In Figure 3, the effective membrane area (15) is the portion of the hollow fiber bundle filled with hollow fibers, excluding the adhesive-fixed portion (14), that is essentially responsible for the separation function. In Figure 3, since the separation function layer is located inside the hollow fibers, the effective membrane area is calculated based on the total internal surface area of ​​the hollow fibers. In the case of hollow fibers with the separation function layer located outside (not shown), the effective membrane area is calculated based on the total external surface area of ​​the hollow fibers.

[0081] Figure 4 is a schematic diagram showing an example of an evaluation method for a hollow fiber membrane module using the evaluation apparatus of the present disclosure. In Figure 4, the forward osmosis membrane module (10) is the hollow fiber membrane module described in Figure 3 above. The hollow fiber membrane module has a forward osmosis membrane (11) composed of hollow fibers consisting of a porous support and a separation functional layer, and the space within the forward osmosis membrane module is separated by the forward osmosis membrane into a space on the porous support side and a space on the separation functional layer side. A raw material liquid line (20) and an induction solution line (30) are prepared. The raw material liquid line (20) is equipped with a raw material liquid supply pump (22) as a raw material liquid supply means for sending the raw material liquid from a raw material liquid tank (21) to the hollow fiber membrane module. The raw material liquid line (20) is fluidly connected to the space on the separation functional layer side and is configured to recover the raw material liquid from the hollow fiber membrane module and return it to the raw material liquid tank for circulation. The induction solution line (30) includes an induction solution supply pump (32) as an induction solution supply means for delivering the induction solution from the induction solution tank (31) to the hollow fiber membrane module. The induction solution line (30) is fluidly connected to the space on the porous support side and is configured to recover the induction solution from the hollow fiber membrane module, return it to the induction solution tank, and circulate it. The induction solution line (30) also includes a pressure adjustment valve (33) as a pressure adjustment means for adjusting the physical pressure of the induction solution and a pressure sensor (34) for measuring the physical pressure of the induction solution on the line that recovers the induction solution from the hollow fiber membrane module. The pressure adjustment valve (33) and pressure sensor (34) are connected to a control device (not shown) and are configured to compare the physical pressure difference between the raw material liquid and the induction solution in real time and adjust the physical pressure difference to be constant within a range greater than 0 kPa and less than or equal to 200 kPa, with the porous support side being positive. [Examples]

[0082] 《Measurement method》 <Dimensions of the support membrane> When the support membrane is a hollow fiber support membrane, the inner diameter, outer diameter, and membrane thickness of the support membrane were measured. In the case of the hollow fiber support membrane, the dimensions were measured using an optical micrograph (cross-sectional image) of the cross-section obtained by cutting in a plane perpendicular to the membrane surface direction (longitudinal direction). The outer diameter and inner diameter of this cross-sectional image were measured using a scale. Also, the membrane thickness was calculated by dividing the difference between the outer diameter and the inner diameter by 2. The outer diameter and inner diameter referred to here are the outer diameter and inner diameter of the hollow fiber, respectively. The inner diameter, outer diameter, and membrane thickness of the support membrane are measured in the state of only the hollow fiber support membrane in principle, but the values measured in the state of the forward osmosis membrane (the state having a separation functional layer on the inner surface of the hollow fiber support membrane) may be substituted. Note that even when measured in the state of the forward osmosis membrane, it is confirmed that it is within the error range when measured in the state of only the hollow fiber support membrane and is substantially the same.

[0083] <<Manufacturing Example of Forward Osmosis Membrane>> <Manufacturing Example 1> Production of hollow fiber support membrane: As a spinning dope, a uniform polymer solution composed of 19% by mass of polysulfone (manufactured by Solvay Specialty polymers, Udel-P3500), 61% by mass of N-methyl-2-pyrrolidone (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), and 20% by mass of tetraethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) was prepared. The above dope was filled into a wet hollow fiber spinning machine equipped with a double spinneret. From the double spinneret, the dope at 40°C and the internal coagulation liquid (water) at 25°C were discharged, and it was made to travel 250 mm in air at a temperature-controlled 30°C and a relative humidity of 98%. Then, it was coagulated in a coagulation bath (external coagulation liquid) filled with water at 30°C, and wound up with a tension of 20 g using a free roll as a turn roll to obtain a hollow fiber support membrane. The obtained hollow fiber support membrane had an outer diameter of 1.02 mm, an inner diameter of 0.62 mm, and a membrane thickness of 0.20 mm.

[0084] Production of support membrane module: 130 of the above hollow fiber support membranes were cut to 120 mm, filled into a cylindrical plastic housing with a diameter of 20 mm and a length of 100 mm, fixed at both ends with an adhesive, and then cut to open the end face, so that the effective length was 80 mm and the effective membrane inner surface area was 0.02 m 2A support membrane module was fabricated.

[0085] Formation of the separation functional layer: An aqueous solution (first solution) containing 2.0% by mass of m-phenylenediamine and 0.15% by mass of sodium lauryl sulfate was passed through the inside of the hollow fibers of the support membrane module for 20 minutes. After the passage was complete, the first solution was drained by gravity from the piping at the bottom of the module. With the inside of the hollow fibers still wet with the first solution, the outside of the support membrane module was reduced to 90 kPaG and the reduced pressure was maintained for 1 minute. Then, air was flowed through the inside of the hollow fibers for 1 minute to remove excess first solution. Subsequently, an n-hexane solution (second solution) containing 0.20% by mass of trimesinate chloride was passed through the inside of the hollow fibers for 2 minutes to induce interfacial polymerization and form a separation functional layer on the inner surface of the hollow fibers. Then, excess second solution was removed by flowing nitrogen gas, and then 85°C hot water was flowed through the inside of the hollow fibers for 30 minutes. Subsequently, the module was placed in an autoclave (SX-500, manufactured by Tommy Seikou Co., Ltd.) with the interior and exterior open, and a supply of 121°C high-temperature steam was continuously applied to the chamber for 20 minutes. Furthermore, the inside of the hollow fibers was washed with 20°C water for 30 minutes to obtain a forward osmosis membrane module.

[0086] <Manufacturing Example 2> Fabrication of hollow fiber support membranes: A homogeneous polymer solution was prepared as the spinning stock, consisting of 18% by mass of hydroxylated-terminated polyethersulfone (BASF, Ultrason E2020PSR) and 80% by mass of N,N-dimethylacetamide (Fujifilm Wako Pure Chemical Industries, Ltd.). The stock solution was filled into a wet hollow fiber spinning machine equipped with a double spinning head. The stock solution at 40°C and the internal coagulation solution at 45°C were discharged from the double spinning head and the machine was run for 200 mm through air heated to 30°C and with a relative humidity of 98%. Subsequently, the material was coagulated in a coagulation bath (external coagulation solution) filled with 50°C water, and the material was wound using a free roll as the turn roll with a tension of 10 g to obtain a hollow fiber support film. At this time, a solution consisting of 50% by mass of water and 50% by mass of tetraethylene glycol was used as the internal coagulation solution. The obtained hollow fiber support film had an outer diameter of 1.00 mm, an inner diameter of 0.70 mm, and a film thickness of 0.15 mm.

[0087] Fabrication of support membrane modules and formation of separation functional layers: A forward osmosis membrane module was fabricated in the same manner as in Example 1, except that the hollow fiber support membrane described above was used.

[0088] <Manufacturing Example 3> A forward osmosis membrane module was fabricated in the same manner as in Manufacturing Example 1, except that autoclaving was not performed in the formation of the separation functional layer.

[0089] Furthermore, it has been found that Manufacturing Example 1 is a method for stably obtaining a forward osmosis membrane module with high performance, Manufacturing Example 2 is a method for stably obtaining a forward osmosis membrane module with high performance, and Manufacturing Example 3 is a method for stably obtaining a forward osmosis membrane module with intermediate performance. In this embodiment, high performance refers to an RSF / Flux value of 0.04 g / L (g / kg) or less at a membrane differential pressure of 20 kPa (high pressure on the induction solution side) in the basic performance evaluation, low performance refers to an RSF / Flux value of 0.08 g / L (g / kg) or more, and intermediate performance refers to an RSF / Flux value greater than 0.04 g / L (g / kg) but less than 0.08 g / L (g / kg).

[0090] 《Forward Osmosis Membrane Evaluation System》 An example of a device that can be configured as a forward osmosis membrane evaluation device is shown below, but the present invention is not limited to the following example of device. Temperature-controlled chiller: NCC-3000C (Tokyo Rikaki Co., Ltd.), temperature control range -10 to 80°C Double-tube heat exchanger: HEX-MHE-20A-200-T (MDI Corporation), all titanium. Pump: GJ Series (Sanwa Tsusho Co., Ltd.) Magnetic Gear Pump Pressure sensor: GP-M series (GP-M010T) (Keyence Corporation) Flow sensor: FD-X series (FD-XS8) (Keyence Corporation) Balance: EA715CA-22 (A&D Company, Limited) Conductivity sensor: DS70 series (Horiba, Ltd.) In-line type Refractive index sensor: L-Rix series (L-Rix 5200) (Anton Paar) In-line type Temperature sensor: Inline temperature sensor L-type (Toho Electronics Co., Ltd.) Back pressure valve: 44-2300 series (Tescom) - opening / closing degree controlled by motor. Data logger: GL840 series (Graphtec Corporation)

[0091] Examples 1-20, Comparative Examples 1-4, and Reference Example 1 The forward osmosis membrane evaluation apparatus was configured as follows using the above-mentioned equipment. First, a raw material liquid tank and a raw material liquid line connecting the raw material liquid tank to the forward osmosis membrane module were prepared. The raw material liquid tank and the induction solution tank were equipped with the above-mentioned balances below them. The balances could measure the weight changes of the raw material liquid and the induction solution tank, and based on the weight change of the raw material liquid, the water permeability could be measured. On the raw material liquid line, the above-mentioned pump for supplying the raw material liquid from the raw material liquid tank to the forward osmosis membrane module created in the above-mentioned manufacturing example, and a flow meter for measuring the flow rate of the raw material liquid were installed. The raw material liquid line had a bypass line that allowed the raw material liquid to be circulated in advance before being connected to the forward osmosis membrane module. In addition, one of the above-mentioned pressure sensors for measuring the physical pressure of the raw material liquid was installed on the inlet side and one on the outlet side of the module on the raw material liquid line. The heat transfer medium of the above-mentioned temperature control chiller was connected to enter the above-mentioned double-tube heat exchanger, and the raw material liquid line was arranged to flow inside the double-tube heat exchanger. A thermometer for measuring the temperature of the raw material liquid was installed on the raw material liquid line that exited the double-tube heat exchanger. This ensures that the raw material liquid is temperature-controlled before entering the forward osmosis membrane module. The raw material liquid flows out of the raw material liquid tank, passing through a pump, flow meter, pressure gauge (inlet pressure), heat exchanger, thermometer, forward osmosis membrane module, pressure gauge (outlet pressure) in that order, and then returning to the raw material liquid tank. An induction solution tank and an induction solution line connecting the induction solution tank to the forward osmosis membrane module were provided. The induction solution line had a bypass line that allowed the induction solution to be circulated in advance before connecting to the forward osmosis membrane module. On the induction solution line, the pump that supplies the induction solution from the induction solution tank to the forward osmosis membrane module and a flow meter for measuring the flow rate of the induction solution were installed. On the induction solution line, the back pressure valve was installed to physically pressurize the induction solution and adjust the physical pressure difference between the raw material liquid and the induction solution. In addition, one pressure sensor each was installed on the inlet and outlet sides of the module to measure the physical pressure of the induction solution on the induction solution line. The heat transfer medium of the above-mentioned temperature-controlling chiller is connected to enter the above-mentioned double-tube heat exchanger, and the raw material liquid line and the induction solution line are arranged to flow inside the double-tube heat exchanger.A thermometer was installed on the induction solution line exiting the double-tube heat exchanger to measure the temperature of the induction solution. This ensured that the induction solution was temperature-controlled before entering the forward osmosis membrane module. The flow of the induction solution was as follows: it exited the induction solution tank, passed through the pump, flow meter, pressure gauge (inlet pressure), heat exchanger, thermometer, forward osmosis membrane module, pressure gauge (outlet pressure), and back pressure valve in that order, and then returned to the induction solution tank. This forward osmosis membrane evaluation apparatus was used to evaluate the basic performance of the forward osmosis membranes in Examples 1-20, Comparative Examples 1-4, and Reference Example 1, which are described below.

[0092] <Basic performance evaluation of forward osmosis membranes> For the forward osmosis membranes obtained in Production Examples 1-3, forward osmosis operation was performed under the following conditions, and then the water permeability (Flux) and salt back diffusion rate (RSF) were determined, and the salt permeability (RSF / Flux) was calculated. Raw material liquid: Purified water, 25℃, flow rate approximately 88mL / min (linear velocity approximately 3.7cm / sec, residence time approximately 2 seconds), solution volume 3L Induction solution: 3.5% by mass sodium chloride aqueous solution, 25°C, flow rate 390 mL / min (linear velocity approximately 3.7 cm / sec, residence time approximately 2 seconds), solution volume 3 L Physical pressure difference: 20kPa, pre-circulated through a bypass line and adjusted by a back pressure valve on the induction solution side. Temperature: Pre-adjusted using a double-tube heat exchanger and a temperature-controlled chiller. Operating time: Start by passing the raw material liquid, then the induction solution, and continue for 20 minutes from the time the induction solution is first discharged from the module. However, in Example 7, the temperature of the raw material solution was adjusted to 15°C and the temperature of the derived solution to 30°C.

[0093] Forward osmosis operation was performed by adding saturated sodium chloride aqueous solution to the induction solution while maintaining a constant concentration of the induction solution. The intermembrane pressure differential was set to positive (high pressure) on the induction solution side (the support membrane side of the forward osmosis membrane) by operating the back pressure valve on the induction solution side. Each measurement was performed once on five modules manufactured using the same manufacturing method. However, for Reference Example 1, one module manufactured in the same manner as in Example 1 was evaluated five times. For Examples 19 and 20, and Comparative Example 4, a total of five modules were manufactured using two different manufacturing methods (three of one type and two of the other), and each was measured once. The mean and standard deviation were calculated from the five obtained RSF / Flux values, and the coefficient of variation was calculated by dividing the standard deviation by the mean and expressed as a percentage.

[0094] Examples 21 and 22 For Examples 21 and 22, a forward osmosis membrane apparatus consisting of the following configuration was used for the basic performance evaluation of the forward osmosis membrane. First, a raw material liquid tank and a raw material liquid line connecting the raw material liquid tank to the forward osmosis membrane module were prepared. The raw material liquid tank and the induction solution tank were equipped with the above-mentioned balance below them. The balance can measure the weight change of the raw material liquid and the induction solution tank, and can measure the water permeability based on the weight change of the raw material liquid. On the raw material liquid line, the above-mentioned pump for supplying the raw material liquid from the raw material liquid tank to the forward osmosis membrane module created in the above manufacturing example, and a flow meter for measuring the flow rate of the raw material liquid were installed. The raw material liquid line had a bypass line that allowed the raw material liquid to be circulated in advance before being connected to the forward osmosis membrane module. In addition, one of the above-mentioned pressure sensors for measuring the physical pressure of the raw material liquid was installed on the raw material liquid line, one on the inlet side and one on the outlet side of the module. Furthermore, one of the above-mentioned conductivity sensors for measuring the conductivity of the raw material liquid was installed on the raw material liquid line, one on the inlet side and one on the outlet side of the module. The heat transfer medium of the temperature-controlled chiller was connected to the double-tube heat exchanger, and the raw material liquid line was arranged to flow inside the double-tube heat exchanger. A thermometer was installed on the raw material liquid line after it exited the double-tube heat exchanger to measure the temperature of the raw material liquid. This ensured that the raw material liquid was temperature-controlled before entering the forward osmosis membrane module. The raw material liquid flow was a single-pass flow, leaving the raw material liquid tank and passing through a pump, flow meter, conductivity meter (inlet conductivity), pressure gauge (inlet pressure), heat exchanger, thermometer, forward osmosis membrane module, pressure gauge (outlet pressure), conductivity meter (outlet conductivity) in that order, and then being collected in a separate tank without returning to the raw material liquid tank. A balance was installed below the separate tank to measure the weight of the raw material liquid that came out in a single pass. An induction solution tank and an induction solution line connecting the induction solution tank to the forward osmosis membrane module were prepared. The induction solution line had a bypass line that allowed the induction solution to be circulated in advance before connecting to the forward osmosis membrane module. A pump for supplying the induction solution from the induction solution tank to the forward osmosis membrane module, and a flow meter for measuring the flow rate of the induction solution were installed on the induction solution line. A back pressure valve was also installed on the induction solution line to physically pressurize the induction solution and adjust the physical pressure difference between the raw material liquid and the induction solution.Furthermore, one pressure sensor for measuring the physical pressure of the induction solution was installed on the induction solution line, one on the inlet side and one on the outlet side of the module. The heat transfer medium of the temperature-controlled chiller was connected to enter the double-tube heat exchanger, and the raw material liquid line and the induction solution line were arranged to flow inside the double-tube heat exchanger. A thermometer was installed on the induction solution line after it exited the double-tube heat exchanger to measure the temperature of the induction solution. As a result, the induction solution was temperature-controlled before it entered the forward osmosis membrane module. The flow of the induction solution was as follows: it left the induction solution tank, passed through the pump, flow meter, pressure gauge (inlet pressure), heat exchanger, thermometer, forward osmosis membrane module, pressure gauge (outlet pressure), and back pressure valve in that order, and then returned to the induction solution tank.

[0095] For Examples 21 and 22, the raw material liquid flowed in a single pass, and the RSF was calculated by measuring the conductivity and weight of the raw material liquid discharged from the forward osmosis membrane module. Flux was calculated from the weight increase of the induction solution. The induction solution was pre-circulated and pressurized in the forward osmosis membrane module, and then the raw material liquid was passed through for evaluation. For Example 21, the stabilization time was defined as 0 seconds from the moment the raw material liquid began to be discharged from the forward osmosis membrane module, and data from 30 seconds onward was used for evaluation. For Example 22, no stabilization time was set, and data was used for evaluation from the moment the raw material liquid was discharged from the forward osmosis membrane module and measurement became possible. The raw material liquid flow rate was set to a single pass of approximately 30 mL / min, and the induction solution flow rate was circulated at approximately 100 mL / min. Other conditions were as described in the table, but otherwise the evaluation was carried out in the same manner as in Example 1. The time required for the evaluation interval, including equipment cleaning and raw material liquid concentration adjustment after evaluation, was 10 minutes or more for Example 1, while it was within approximately 2 minutes for Examples 21 and 22.

[0096] For inorganic salts, the RSF was calculated by using a pre-prepared calibration curve and determining the weight of the induced solute that migrated from the induction solution to the raw material solution from the electrical conductivity values ​​measured by a conductivity meter. If there were multiple components involved in conductivity, the amount of cations ionized from the induced solute being measured was similarly determined by continuously measuring them using an ICP-MS (Inductively Coupled High-Frequency Plasma Mass Spectrometer), model "iCAP Q," manufactured by Thermo Fishier Scientific. For example, in Reference Example 1, it was calculated by measuring Na+. In Example 17, the RSF was calculated by measuring Na+ from NaCl. For organic substances, the RSF was calculated by using a pre-prepared calibration curve and determining the weight of the induced solute that migrated from the induction solution to the raw material solution from the area values ​​of each peak measured by gas chromatography. Note that the performance of the forward osmosis membrane depends on the differential pressure between membranes; the higher the pressure on the induction solution side, the greater the amount of salt that migrates from the induction solution to the raw material solution. This is because the so-called reverse osmosis process, which applies pressure against the osmotic pressure difference, is being applied simultaneously with the forward osmosis process, but in the opposite direction.

[0097] <Simulated liquid operation> Next, to confirm the practical performance of the forward osmosis membranes obtained in Manufacturing Examples 1-3, forward osmosis treatment was performed under the following conditions. After evaluating the basic performance of the forward osmosis membrane modules, the modules were washed with water for more than 5 hours, and the following simulated solution was concentrated 5 times. Measurements were taken once for each of the 5 modules, for a total of 5 measurements. However, for Reference Example 1, one module was evaluated 5 times. Raw material solution: Add magnesium chloride to a 20% by mass aqueous solution of sucrose, and the Mg in the solution 2+ A simulated solution was prepared by diluting the solution to achieve an ion concentration of 60 ppm by mass. Initial temperature: 20°C, flow rate: approximately 88 mL / min (linear velocity approximately 3.7 cm / sec, residence time approximately 2 seconds), solution volume: 10 L Induction solution: 30% by mass magnesium chloride aqueous solution, initial temperature 25°C, flow rate 390 mL / min (linear velocity approximately 3.7 cm / sec, residence time approximately 2 seconds), solution volume 10 L Physical pressure difference: No adjustment was made; it was left to chance. However, the pumping of the raw material liquid and induction solution by tube pump caused pulsation, which in turn added pressure fluctuations. Since the pressure caused by pulsation also depended on the viscosity of the solution, the physical pressure difference changed over time. Temperature: No adjustment, left to chance, ambient temperature 25℃ Operating time: Scales were pre-marked on the raw material liquid tank and the induction solution tank so that the volume of liquid inside could be calculated from the liquid level. The amount of water moved was measured from the change in the liquid level in the raw material liquid tank. Based on the amount of water moved from the raw material liquid to the induction solution, the operation was stopped when approximately 5 times concentration had progressed (when the raw material liquid reached 2L), and the amounts of water and each salt moved were measured separately.

[0098] The initial concentration of the diluted induction solution was maintained by adding small amounts of saturated induction solution during the measurement, and the measurement was performed at 25°C. For calculating the amount of salt migration, the cation (Mg derived from magnesium chloride, the solute of the induction solution) was used. 2+ The amount of ions was measured using an inductively coupled plasma-mass spectrometer (ICP-MS) of the "iCAP Q" type, manufactured by Thermo Fishier Scientific.

[0099] <Evaluation of Mg concentration after concentration of simulated solution: Practical variability evaluation> As a guideline for practical variability evaluation, after concentrating the simulated solution with 5 modules each (1 module x 5 times in Reference Example 1), the amount of Mg diffused from the derived solution into the raw material solution was measured. 2+ The difference between the maximum and minimum ion concentrations, i.e., the difference between the highest and lowest values ​​among the five samples (five times in Reference Example 1), was calculated and evaluated according to the following criteria A to C. The results are shown in Table 1. A: Mg in the raw material liquid after concentration 2+ When the difference between the maximum and minimum ion concentrations is less than 100 ppm by mass B: Mg in the raw material liquid after concentration 2+ When the difference between the maximum and minimum ion concentrations is between 100 ppm by mass and less than 500 ppm by mass. C: Mg in the raw material liquid after concentration 2+ When the difference between the maximum and minimum ion concentrations is 500 ppm by mass or more

[0100] <Assessment of evaluation accuracy> The evaluation accuracy was assessed based on the basic performance evaluation results of the forward osmosis membrane and the practical variability results of simulated liquid operation. When the basic performance evaluation results of a forward osmosis membrane module accurately evaluate the practical performance of the forward osmosis membrane, the variability in the simulated liquid tends to be low (Evaluation A) when the RSF / Flux coefficient of variation of the basic performance evaluation results is 20% or less, when it is 20% to 40%, when it is a certain degree of variability in the simulated liquid (Evaluation B), and when it exceeds 40%, when it is a large variability in the simulated liquid (Evaluation C). Therefore, those that followed this trend were classified as having good accuracy (B), and among them, those with an RSF / Flux coefficient of variation of 10% or less in the basic performance evaluation results, indicating better performance evaluation, were classified as having excellent accuracy (A). Those that did not follow this trend were classified as having poor accuracy (C).

[0101] The measurement and evaluation results are shown in Tables 1-4 below. The abbreviations used in the tables are as follows: FS:Feed Solution (raw material liquid) DS:Draw Solution NaCl: Sodium chloride (aqueous solution) MgCl2: Magnesium chloride (aqueous solution) MgSO4: Magnesium sulfate (aqueous solution) IPA: Isopropyl alcohol (aqueous solution) MeCN: Acetonitrile

[0102] [Table 1]

[0103] [Table 2]

[0104] [Table 3]

[0105] [Table 4]

[0106] As shown in Tables 3 and 4, the evaluation methods in the examples accurately evaluated the practical performance of the forward osmosis membrane. In the evaluation method of Comparative Example 1, the pressure of the induction solution was atmospheric pressure (0 kPa), so the evaluation could not be performed accurately. In the evaluation method of Comparative Example 2, the pressure of the induction solution was atmospheric pressure (0 kPa), and the raw material liquid was pressurized (20 kPa), but the evaluation could not be performed accurately. In the evaluation method of Comparative Example 3, the pressure of the induction solution was high at 350 kPa, so it is thought that the separation functional layer peeled off or was destroyed. Reference Example 1 is an example in which variations due to individual differences in modules were eliminated by repeatedly measuring the same module, and it shows that the evaluation method of this disclosure has a small coefficient of variation in performance evaluation and high evaluation accuracy. [Industrial applicability]

[0107] The evaluation method and evaluation apparatus disclosed herein can be used to measure the practical performance of a forward osmosis membrane, and are particularly suitable for measuring the practical performance of a forward osmosis membrane including a support membrane and a separation functional layer. [Explanation of Symbols]

[0108] 10 Forward Osmosis Membrane Modules 10a Space on the porous support side 10b Space on the separation function layer side 11 Forward osmosis membrane 11a Porous support 11b Separation functional layer 12 Inner conduit 13 Outer conduit 14 Adhesive fixing part 15 Effective film area portion 20 Raw material liquid line 21 Raw material liquid tank 22 Raw material liquid supply pump 30 Induction Solution Line 31 Induction Solution Tank 32 Induction solution supply pump 33 Pressure regulating valve 34 Pressure Sensor 100 Evaluation System for Forward Osmosis Membrane Modules P1 Solvent movement direction P2 Direction of physical pressure application

Claims

1. A method for evaluating a forward osmosis membrane module having a space separated by a forward osmosis membrane, The forward osmosis membrane comprises a support membrane with a porous support and a separation functional layer provided on the porous support. The above method is as follows: The process involves preparing a raw material line for supplying a raw material liquid containing a solvent to the forward osmosis membrane module, and an induction solution line for supplying an induction solution with a higher osmotic pressure than the raw material liquid to the forward osmosis membrane module. The process of connecting the space on the separation functional layer side of the forward osmosis membrane module to the raw material liquid line, and the space on the porous support side to the induction solution line, A step of moving the solvent in the raw material liquid into the induction solution while adjusting the physical pressure difference between the raw material liquid and the induction solution to be constant within a range greater than 0 kPa and less than or equal to 200 kPa, with the porous support side being positive, through the forward osmosis membrane, and adjusting the physical pressure difference between the two membranes to be constant within a range greater than 0 kPa and less than or equal to 200 kPa, with the porous support side being positive. A method for evaluating forward osmosis membrane modules, including the method described above.

2. The method according to claim 1, further comprising the step of adjusting the physical pressure of the induction solution to greater than 0 kPa and less than or equal to 200 kPa while circulating the induction solution outside the forward osmosis membrane module, before the step of connecting the forward osmosis membrane module to the raw material liquid line and the induction solution line.

3. The method according to claim 1 or 2, wherein the physical pressure difference is 20 kPa to 100 kPa.

4. The method according to claim 1 or 2, further comprising the step of adjusting the temperature difference between the raw material liquid and the induction solution to within 10°C before connecting the forward osmosis membrane module to the raw material liquid line and the induction solution line.

5. The method according to claim 1 or 2, further comprising the step of adjusting the flow rates of the raw material liquid and the induction solution before connecting the forward osmosis membrane module to the raw material liquid line and the induction solution line, so that after connecting the forward osmosis membrane module, the difference between the residence time of the raw material liquid in the space on the separation functional layer side and the residence time of the induction solution in the space on the porous support side is within 20 seconds.

6. The method according to claim 1 or 2, wherein the solvent is water.

7. The method according to claim 6, wherein the raw material liquid is supplied to the forward osmosis membrane module, and then the induction solution is supplied.

8. The method according to claim 1 or 2, wherein the solution containing the raw material liquid that has been supplied to the forward osmosis membrane module and exited the forward osmosis membrane module does not return to the raw material liquid tank.

9. The method according to claim 8, wherein the performance of the forward osmosis membrane is evaluated by measuring the difference between the raw material liquid and a solution containing the raw material liquid supplied to the forward osmosis membrane module and after it has left the forward osmosis membrane module, and measuring at least one difference selected from the group consisting of conductivity, refractive index, total organic carbon, chemical oxygen demand, biochemical oxygen demand, absorbance, and transmittance, and comparing the said item with the derived solution.

10. The method according to claim 8, wherein the evaluation is started 10 seconds or more after the raw material liquid is first discharged from the forward osmosis membrane module.

11. The method according to claim 1 or 2, wherein the induced solute contained in the induced solution is at least one selected from inorganic salts and hydrophilic organic compounds.

12. The method according to claim 11, wherein the number average molecular weight of the derived solute is 20 to 300.

13. The method according to claim 11, wherein the derived solute contains a monovalent salt.

14. The method according to claim 11, wherein the derived solute comprises an alcohol having 1 to 4 carbon atoms and / or acetonitrile.

15. The method according to claim 11, wherein the concentration of the induced solute is 1% by mass or more based on the total mass of the induced solution.

16. The method according to claim 1 or 2, wherein the forward osmosis membrane module is a hollow fiber membrane module.

17. An evaluation apparatus for a forward osmosis membrane module having a forward osmosis membrane, A raw material liquid tank for storing the raw material liquid, A raw material liquid line connects the raw material liquid tank to the forward osmosis membrane module, A raw material supply means that supplies the raw material from the raw material tank to the forward osmosis membrane module through the raw material line, An induction solution tank containing an induction solution with a higher osmotic pressure than the aforementioned raw material liquid, An induction solution line connects the induction solution tank to the forward osmosis membrane module, An induction solution supply means that supplies the induction solution from the induction solution tank to the forward osmosis membrane module through the induction solution line, A pressure adjustment means installed on the induction solution line, capable of physically pressurizing the induction solution before, during, and after evaluation of the forward osmosis membrane module, wherein the pressure adjustment means is configured to maintain a constant physical pressure difference between the induction solution and the physical pressure of the raw material solution via the forward osmosis membrane, within a range greater than 0 kPa and less than or equal to 200 kPa. A pressure sensor installed on the induction solution line and capable of measuring the physical pressure of the induction solution, Equipped with, An evaluation apparatus for a forward osmosis membrane module having a forward osmosis membrane having a support membrane with a porous support and a separation functional layer provided on the porous support.

18. The evaluation apparatus according to claim 17, wherein the induction solution line has a circulation structure that allows the induction solution to be circulated outside the forward osmosis membrane module before being connected to the forward osmosis membrane module, and comprises an induction solution bypass line that constitutes a part of the circulation structure of the induction solution line and can be attached to and detached from the forward osmosis membrane module.

19. The evaluation apparatus according to claim 17 or 18, wherein the raw material liquid line has a circulation structure that allows the raw material liquid to be circulated outside the forward osmosis membrane module before being connected to the forward osmosis membrane module, and comprises a raw material liquid bypass line that constitutes a part of the circulation structure of the raw material liquid line and can be attached to and detached from the forward osmosis membrane module.

20. The evaluation apparatus according to claim 17 or 18, further comprising at least one selected from pressure adjustment means and temperature adjustment means on the raw material liquid line.

21. The evaluation apparatus according to claim 17 or 18, further comprising a temperature control means on the induction solution line.

22. The evaluation apparatus according to claim 17 or 18, further comprising on the raw material liquid line at least one selected from the group consisting of a pressure sensor, a temperature sensor, a flow rate sensor, an conductivity sensor, and a refractive index sensor.

23. The evaluation apparatus according to claim 17 or 18, further comprising on the induction solution line at least one selected from the group consisting of a temperature sensor, a flow sensor, a conductivity sensor, and a refractive index sensor.

24. The evaluation apparatus according to claim 17 or 18, wherein the raw material liquid tank or the induction solution tank, or both, are provided with a temperature control means.

25. The evaluation apparatus according to claim 17 or 18, wherein the raw material liquid tank or the induction solution tank, or both, are equipped with at least one selected from the group consisting of a temperature sensor, an conductivity sensor, and a refractive index sensor.

26. The evaluation apparatus according to claim 17 or 18, comprising multiple sets of the raw material liquid line and the induction solution line, and capable of evaluating multiple forward osmosis membrane modules in parallel.

27. The evaluation apparatus according to claim 17 or 18, configured to monitor in real time the values ​​and times measured by each sensor and store them in a database, and to detect the difference between the values ​​of the raw material liquid, the induction solution, or both during solution circulation before evaluation and the values ​​during evaluation of the forward osmosis membrane module.

28. The raw material liquid line is equipped with a pressure adjustment means, a pressure sensor, and a flow rate sensor. The induction solution line is further equipped with a flow sensor, The evaluation apparatus further comprises a control device coupled to the pressure sensor, flow sensor, and pressure adjustment means on the raw material liquid line and the induction solution line, respectively, and the raw material liquid supply means and the induction solution supply means, The evaluation apparatus according to claim 17 or 18, wherein the control device is configured to compare the physical pressure difference, flow rate, and minimum flow rate of the raw material liquid and the induction solution in real time, and is configured to control the pressure adjustment means, the raw material liquid supply means, and the induction solution supply means to maintain a desired physical pressure difference and a flow rate equal to or greater than the minimum flow rate.

29. The evaluation apparatus according to claim 28, configured to maintain the real-time physical pressure difference within ±1 kPa of the desired physical pressure difference.

30. The evaluation apparatus according to claim 28, configured to determine and pre-control the pressure and flow rate of the induction solution before evaluating the forward osmosis membrane module by inputting information on the cross-sectional area of ​​the raw material supply section and the induction solution supply section within the forward osmosis membrane module, a desired physical pressure difference, and a desired minimum flow rate of the raw material.

31. The evaluation apparatus according to claim 28, wherein the control device includes a processor configured to execute a proportional-integral-derivative control algorithm.

32. The evaluation apparatus according to claim 17 or 18, wherein the induction solution line and / or induction solution tank further comprises concentration adjustment means capable of performing at least one of the following: removing a solvent from the induction solution, adding a high-concentration induction solution to the induction solution, or adding an induction solute.

33. The evaluation apparatus according to claim 17 or 18, wherein the forward osmosis membrane module is a hollow fiber membrane module.

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