WO2017018764A1 - Method for concentrating solute-containing aqueous solution at high concentration by reverse osmosis method in non-osmotic pressure difference state - Google Patents

Abstract

The present invention relates to a method for concentrating an aqueous solution with low pressure in a non-osmotic pressure difference state and, more specifically, to a method for concentrating a solute-containing aqueous solution to be concentrated with low pressure in a non-osmotic pressure state. When the method of the present invention is used, energy consumption is reduced, and the aqueous solution can be concentrated, without using an extraction solution, until the saturated aqueous solution of the maximum solute is prepared or the concentration of the solute is 100%. In addition, the method has an advantage of not requiring the use of a separate osmotic induction solution.

Description

Concentration of solute-containing aqueous solution at high concentration by reverse osmosis in the absence of osmotic pressure difference

The present invention relates to a method of concentrating a solute-containing aqueous solution at high concentration, and more particularly, to a method of concentrating a solute-containing aqueous solution to be concentrated at a high concentration by removing water by a hydraulic-membrane process in the absence of an osmotic pressure difference.

Reverse osmosis (RO), the most widely used seawater desalination process, recently used high-osmotic solutions in draw chambers to recover water from seawater or sewage, to separate osmotic inducing substances and water. Table 1 below compares the advantages and disadvantages of the forward osmosis (FO) regeneration method and the method of concentrating the solute-containing aqueous solution at a high concentration by the hydraulic-membrane process in the absence of an osmotic pressure difference.

RO has only 50% solvent recovery and most of all, it is difficult to operate at 343.070 bar of 3% -NaCl saturated solution (26.47%) to recover 100% solvent and solute. FO has the advantage of operating at atmospheric pressure, but it is necessary to regenerate the draw solution and it is not easy to recover the solute when the solute in the feed crosses to the draw solution (Jung et al. Process Biochemistry (2015) 50 (4) 669-677 ). On the other hand, the method of concentrating the solute-containing aqueous solution to a high concentration by using the hydraulic membrane process in the absence of osmotic pressure difference (△ π = 0 method) has to overcome the osmotic pressure difference caused by the process between the feed chamber and the draw chamber. There is this.

Currently, the membrane method is being researched to produce electric power by forward osmosis method in addition to reverse osmosis method, and if successfully developed, it has the possibility of simultaneously solving the water problem and energy problem. If the reason for limitation in Table 2 is solved technically and economically, it is expected to have a big impact on chemical industry / biotechnology industry and environmental industry.

In the membrane method, the flux of the solvent (water) and the movement of the solutes (salt, VFA, ethanol) are as follows.

Jw = Lp (△ P -σ △ π) ----- (1)

Js = Cs (1-σ) Jw + ω △ π ----- (2)

Here, Jw is the water flux, Lp is the water permeation coefficient, ΔP is the hydraulic pressure difference between the feed chamber and the draw chamber, Δπ is the osmotic pressure difference between the feed chamber and the draw chamber. In addition, the Js is divided into one due to the difference in osmotic pressure and one due to the flux of the solute.

When there is no Jw in Equation (2), the solute may move to the feed chamber by the draw chamber due to the osmotic pressure difference. σ is the reflection coefficient of the solute film. If σ = 1, the solute is completely untransmitted, and the osmotic pressure difference between the two chambers is maximum.

Osmotic pressure is represented by π = CRT ------------------ (3).

Here, C means concentration, R means gas constant, and T means temperature.

In the case of a high concentration solution containing a large amount of solute, Lewis approximation

π = RT / v _sp ln (1-γX) ----------------- (4)

(Ref .: Lewis, GN, The osmotic pressure of concentrated solutions and the laws of perfect solution.Journal of the American Chemical Society 1908, 30, 668-683.).

Where Vsp is the volume of 1 mole of solvent when the solute concentration is 0, γ is the activity coefficient of the solvent, and X is the mole fraction of the solute.

When 30 g / L of solute is dissolved in water, the salt has an osmotic pressure of 25.4 bar, albumin 0.01 bar and particles 1.2x10 ^-12 bar.

Reverse osmosis and forward osmosis have the advantage of saving energy by using membranes, but as the concentration progresses, the osmotic pressure in the feed chamber increases, making it impossible to concentrate the feed solution or increase the utilization of the feed solution (Loeb, S, Loeb-Sourirajan Membrane, How it Came About Synthetic Membranes, ACS Symposium Series, 153, 1, 1-9, 1981; Loeb, S., J. Membr. Sci, 1, 49, 1976).

In the above formula (4), mole fraction is used, but in reality, mole (g / L) or wt% is used a lot, so wt% and osmotic pressure will be displayed. The difficulty of molarity is that the osmotic pressure of Lewis is applied to all solutes.However, in case of molarity, the mass is preserved when the solute and solvent are mixed, but the volume is not. Or it is more convenient to measure. Below Table 3 and displays the amount of power required to produce water 1m ³ in △ π = 0 Method osmotic In exemplary% of the 3% NaCl used as a model, the total pre-sale, the solute amount of water per 1g, and each% aqueous solution .

The substances that humanity needs are in the form of solids, liquids, and gases in the ocean, land, and atmosphere, and exist as independent molecules or compounds. The desired material can be obtained through catalysts, chemical reactions, bioreactions and the like.

The inventors have developed a method for concentrating a solute-containing aqueous solution using a non-osmotic pressure concentrator including a feed chamber composed of a forward osmosis and / or reverse osmosis membrane and a π-echolizer chamber to obtain the above materials (International Patent PCT / KR2014 / 000952). However, the above technique uses a part of the concentrate as an induction solution. In this case, when using a small amount of π-echolizer solution, the high osmotic pressure difference formed between the feed chamber and the π-echolizer chamber has to be overcome. In order to solve this problem, the above patent used a method of reducing the residence time of the π-echolizer solution in the π-echolizer chamber, but found a problem with the design of the π-echolizer and required a new method.

Therefore, the present inventors have made diligent efforts to solve the above problems, and when half of the feed solution is operated as the feed chamber and the other half as the π-echolizer chamber, Δπ is removed from the above formulas (1) and (2). By minimizing the osmotic pressure difference (△ π = 0) or low osmotic pressure, the feed solution is concentrated by hydraulic pressure (△ P) alone, which causes the diluted π-echolizer solution to have a low osmotic pressure. After recovering, finally confirming that the energy consumption and operating costs can be minimized while maximizing the concentration of the feed solution, the present invention has been completed.

Summary of the Invention

It is an object of the present invention to maximize the concentration of solute-containing aqueous solutions containing volatile organic acids and various types of low molecular weight substances having similar properties, while the concentration of aqueous solutions and trace solutes can be minimized to minimize energy and operating costs. To provide water.

In order to achieve the above object, the present invention (a) concentrating the solute-containing aqueous solution using an osmotic pressure difference concentrator comprising a feed chamber and a π-echolizer chamber partitioned with a reverse osmosis membrane, one of the following processes Forming a Δπ reduction condition between the feed chamber and the π-echolizer chamber using the above process: (i) (Feed) Input-split cascade process; (ii) (Feed) Output-split counter-current process; And (iii) applying the nano filtration membrane and (b) recovering the concentrated solute-containing aqueous solution using another osmotic pressure difference concentrator or reverse osmosis. Provide a way to.

1 is a diagram illustrating a process of separating 970 g of water and 30 g of salt in a NaCl solution of 3% (w / w) in a zero / low osmotic pressure difference of the present invention, ① and ② indicate a normal reverse osmosis process ③ Means an osmotic pressure difference concentrator.

Figure 2 is a schematic diagram of three methods used to achieve the osmotic pressure / low osmotic pressure difference of the present invention, A means Feed "Input-Split Cascade" method, the high osmotic pressure of any concentration of the inlet solution Divided into two parts, the osmotic pressure difference becomes zero when the feed chamber and the π (Pai) -Equalizer chamber are separated (ie Δπ = 0). The osmotic pressure difference is zero and the feed chamber is concentrated, the feed chamber is concentrated and the π-Equalizer chamber is diluted so that osmotic pressure difference can occur. B is the Feed Output-Split CC (counter-current) method. Example: 50%) is sent to the π-Equalizer chamber and the osmotic pressure difference between the feed output stream and the recycling (equalizer) stream is Δπ = 0. At this time, both streams flow counter-current. For example, if the starting concentration of the feed chamber is 6%, the final concentration of the π-Equalizer stream can be made 3%. C indicates that the use of a membrane with a low solute reflection coefficient allows some of the solute in the feed stream to flow into the π-Equalizer stream to reduce the osmotic pressure difference.The graph on the left shows the difference between the two chambers according to these three methods. Osmotic pressure difference is shown.

Figure 3 shows a device for measuring the ΔP and permeation (LMH = liters / (m2.h) according to the concentration of the solution in the osmotic pressure difference state, (a) is a high pressure feed chamber (A) and an atmospheric pressure draw chamber ( It is an explanatory drawing of a BPS system including B), and (B) is a specific design drawing of A and B.

FIG. 4 is a system diagram that can separate 3% NaCl solution into water and 26.47% saturated solution (or salt) using an input-split cascade system.

5 is a result of calculating the flux and the energy consumption according to an embodiment of the present invention.

6 is a result of calculating the simulation value of the osmotic pressure difference process according to an embodiment of the present invention.

Detailed description of the invention and preferred Embodiment

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is well known and commonly used in the art.

It is well known that the energy required for reverse osmosis is much less than that of conventional multi-stage evaporation techniques. Also, recently studied forward osmosis is more energy than expected for regeneration of draw solutions. It is increasingly important that the forward osmosis method has no significant benefits in seawater desalination compared to the reverse osmosis method due to the loss of the induction solution.

Contrary to seawater desalination, it may be economical to concentrate an aqueous solution containing high value-added low molecular weight materials by reverse osmosis, but thermal methods such as multistage evaporation (MSF) must be used to recover the induction solution. Facility and energy costs are burdensome.

In addition, in the concentration of fermentation broth, it was not difficult to concentrate 3.5% four times by forward osmosis to 14% (solvent basis), but the concentration required in the fermentation industry was almost 20 to 60% by weight of saline solution. Although it varies from 99.5% purity of ethanol to the liquid, it is difficult to achieve a predetermined purpose only by forward osmosis.

In addition, in the case of forward osmosis, a high concentration of induction solution is used, which can be diffused into the feed chamber and mixed with the feed solution. If the rejection rate of the feed solution is less than 100%, it is difficult to recover the solute mixed in the induction solution. .

In the present invention, the water is discharged to the outside of the various types of solute-containing aqueous solution to be concentrated using a reverse osmosis separator, and the concentrated aqueous solution includes a feed chamber and a draw chamber partitioned by a reverse osmosis membrane or an forward osmosis membrane. When the solution is introduced into the feed chamber of the apparatus, and then a solution having the same or slightly osmotic pressure as the aqueous solution introduced into the feed chamber is introduced into the draw chamber, the osmotic pressure difference between the feed chamber and the draw chamber is close to 0 (Δπ = 0), and the pressure is low. It was intended to confirm that the feed solution can be concentrated alone.

Existing patent (international patent no. PCT / KR2014 / 000952) filed by the present inventors adopts a method of recovering salt by a thermal method, and a method of adjusting the residence time of a draw solution by reducing the osmotic pressure difference. Used. However, in the above two methods, it is economical and technically difficult to maintain Δπ at a low osmotic / no osmotic pressure.

In one embodiment of the present invention, when using the (feed) input-split cascade, (feed) output-split count-current or nano filteration membrane application process, the osmotic pressure difference between the feed chamber and the draw chamber is a low osmotic pressure / no osmotic pressure state It was confirmed that it can be maintained as.

In the present invention, the question of whether the feed should be limited to the solute-containing solution after recovering the water by reverse osmosis in a non-osmotic pressure difference concentrator. This confirms that the total energy consumption is reduced while reducing the amount of water drawn from the solute-containing solution (3%) by reverse osmosis, and pure 3% brine (sea water), which has not undergone reverse osmosis-pure manufacturing, Even when added, it was confirmed that the solvent and the solute can be separated with high efficiency.

Accordingly, the present invention in one aspect, (a) the solute-containing aqueous solution is concentrated using an osmotic pressure concentrator comprising a feed chamber and a π-echolizer chamber partitioned with a reverse osmosis membrane, wherein at least one of Forming a Δπ reduction condition between the feed chamber and the π-echolizer chamber using the process: (i) (Feed) Input-split cascade process; (ii) (Feed) Output-split counter-current process; And (iii) applying a nano filtration membrane; And (b) recovering the concentrated solute-containing aqueous solution using another osmotic pressure difference concentrator or reverse osmosis pressure.

In the present invention, (c) another non-intrusive pressure difference concentrator of step (b) further comprises the step of maximizing the recovery of the solute using one or more of the processes (i) to (iii). can do.

In the present invention, the step (a) may be characterized in that it further comprises the step of concentrating the solute-containing aqueous solution to be concentrated before using the reverse osmosis.

In the present invention, the step (b) of concentrating the solute-containing aqueous solution using another osmotic pressure difference concentrator (i) transfers the concentrated aqueous solution to the feed chamber of the osmotic pressure difference concentrator, and is transferred to the feed chamber. Injecting a solution having the same osmotic pressure as the concentrated aqueous solution into the draw chamber to form an osmotic pressure state between the feed chamber and the draw chamber; And (ii) a pressure of up to 0 to 5 atm for forward osmosis (FO) and 10 to 200 atm for reverse osmosis is applied to the feed chamber at zero osmotic pressure, and the water in the concentrated aqueous solution is drawn. And further concentrating the concentrated aqueous solution by transferring to the chamber.

In the present invention, when the osmotic pressure difference between the feed stream supplied to the feed chamber and the π-echoizer supplied to the π-echolizer chamber is increased (i) an input-split cascade process; (ii) an output-split counter-current process; Or (iii) using the process of applying the nano filtration membrane to reduce the difference.

In the present invention, the terms “(feed) input-split cascade process” and “input-split cascade process” refer to half of the feed solution fed to the osmotic pressure concentrator and half to the feed chamber, and half to the π-echoiser chamber. After forming the osmotic pressure difference, the aqueous solution of the feed chamber is concentrated at low pressure, and the concentrated solute-containing aqueous solution is transferred to another osmotic pressure concentrator.

As used herein, the term “Δπ reduction condition” means a condition in which there is no osmotic pressure difference or a very small value between the feed chamber and the π-echolizer chamber. That is, the Δπ reduction condition of the present invention means a case where Δπ is 0 or 1 to 100 bar or less.

The term “(feed) output-split counter-current process” or “output-split counter-current process” of the present invention is characterized by sending a portion of the π-echolizer stream to the feed stream in a concentrated state in an osmotic pressure concentrator. You can do

The term “π (Pai) -echolizer chamber” of the present invention is used in the same sense as the draw chamber, and the dilution of the filter liquid (water) in the feed stream is the same, but the maneuverability in the orthostatic method is concentrated in the draw chamber. Compared to the induction solution, the difference here is the hydraulic pressure (ΔP). For reference, the present inventors tested ΔP in the forward osmosis method, but about 3 atmospheres were the best and the membranes did not succeed.

In the present invention, step (a) may apply steps (i) to (iii), respectively, and (i) and (ii), (i) and (iii), (ii) and (iii) or (i) )) To (iii) may be applied to form the Δπ reduction conditions.

In another embodiment of the present invention it was confirmed that by concentrating 3% brine, salt crystals and water can be obtained by the input-split cascade process and the output-split counter-current process.

That is, in another embodiment of the present invention, 3% brine is completely converted into crystalline form (solid content) by reverse osmosis in 3% NaCl solution in 26.47% saturated solution by input-split cascade process and output-split counter-current process. The process of concentration was simulated and consulted with a crystallization expert to get advice. The input-split cascade process (Figure 2A) is divided into feed stream and π (osmotic pressure) -echolizer stream for each concentration section, solute remains in the feed chamber and only solvent, water, is moved to the π-echoiser to increase the solution concentration in the feed chamber. π-echolizer decreases. However, the osmotic pressure difference (Δπ) between the two chambers can initially be raised from zero to more than one (eg 60 bar), for example a 6% stream can be 9% concentrated and 3% dilution. This depends on the ratio of the size between the two chambers (A) and how much water is filtered out of the feed chamber (filtration / feed chamber = T). That is, by adjusting these two factors (A, T) at any concentration, the desired concentration and dilution can be made, and the concentrated water can be sent up and the diluted water can be separated into water and salt (Example 3 , 4).

In the output-split CC process (Figure 2B), when the input solution is pressurized, only solvent flows from the feed chamber into the π-echoizer chamber, and the input stream is concentrated from 6% to the concentration (26.47%). At the end of the feed chamber, 50% of the saturated feed output stream enters the π-echolizer tank and the osmotic pressure difference between the feed output and π-echolizer input. The concentration decreases as the π-echoizer stream flows into the feed stream and counter-current. The output of the equalizer can only recover 970-83.34 = 886.66 when the saturated concentrate of the feed stream exits the system. Excluding the 500 recovered by RO, only 428.33 would be recovered, resulting in 15 / (15 + 428.33) = 3.38%. Of course, the total recovery of water 470 due to crystallization, etc. is 3.00%.

50% water can be recovered through RO at 3% input and the rest 6% 470L enters recycle unit and returns to π-equalizer output while maintaining Δπ 0 ~ 60 bar. The remainder of the product is returned to the feed stream and recycled, which must be recycled at least twice to remove 30 g of salt (see Example 5).

When recovering the salt in the present invention may be characterized by applying a method using thermal energy or electrical energy well known to those skilled in the art in a saturated solution, or by applying a feed input-split cascade process and a feed output-split counter-current process It is not limited to this.

In another embodiment of the present invention, in order to reduce the osmotic pressure difference between the feed chamber and the draw chamber, a portion of the solute-containing aqueous solution concentrated by the above method is recycled to the draw chamber, but using nano filtration, It was confirmed that the osmotic pressure difference decreased rapidly.

Therefore, in order to reduce the osmotic pressure in the present invention, it may be characterized by using a nanofiltration membrane.

In the present invention, the step (iii) of the step (a) is selected from the beginning when applied to the process (i), the initial selectivity in consideration of the degree of concentrated water recovery and osmotic pressure difference when applied to the process (ii) The higher the late membrane, the greater the osmotic pressure difference may be characterized in that the osmotic pressure difference can be reduced by selecting a membrane with low selectivity, but is not limited thereto.

In the present invention, the reverse osmosis method may be used when producing pure water, and the RO process may be used as a system when producing water.

The saturated solution concentrated by the method of the present invention can produce power using PRO (pressure retarded osmosis) method using river water or seawater.

The osmotic pressure difference concentrator according to the present invention may be composed of a plurality. That is, the feed chamber and the π-echolizer chamber constituting the osmotic pressure difference concentrator are characterized in that it is composed of a multi-stage.

In the present invention, the reverse osmosis membrane or the forward osmosis membrane partitioning the feed chamber and the draw chamber of the osmotic pressure difference concentrator may be used without particular limitation as long as it does not pass the solute and mainly passes the solvent.

In the present invention, the solute means a liquid or solid substance dissolved in water as a solvent.

In the present invention, the solute-containing aqueous solution to be concentrated may include sea water, brackish water, cell metabolites, reaction solutions, and the like, and cell metabolites may be cultured cells of animal cells, plant cells, or microorganisms. The concept includes a primary product, a secondary product, an in vitro secreted protein, a biotransformation, and the like, but may be a suitable process when the molecular weight is small and the osmotic pressure is high.

Examples of the reaction solution include a reaction solution through a chemical reaction and a reaction solution through an enzyme reaction.

The primary products of the microorganisms include organic acids (acetic acid, propionic acid, butyric acid, lactic acid, citric acid, lactic acid, succinic acid, etc.), alcohols (ethanol, butanol, etc.), nucleic acids, amino acids (lysine, tryptophan, etc.), vitamins, polysaccharides, and the like. It may be illustrated, but is not limited thereto.

The secondary products of the microorganisms include antibiotics (such as lung nicillin), enzyme inhibitors, physiologically active substances (taxols, etc.), and the in vitro secreted proteins of the microorganisms include enzymes such as amylase and cellulase, insulin, interferon, and single group antibodies. For example, the biotransformation of the microorganism is a substance produced by using a microorganism or an enzyme, and examples thereof may include steroids, but are not limited thereto.

For example, when ethanol is concentrated using the method of the present invention, the concentration of ethanol can be concentrated in a reverse osmosis concentrator (RO-1) is about 20%, theoretically 20 ~ by the osmotic pressure difference method It is known to be able to concentrate up to 100%. However, membranes that can concentrate ethanol up to 91-100%, such as volatile organic acids (VFA) or salt, have not yet been developed.

In the case of VFA, the saturation degree is about 50 to 60 wt%, so it is theoretically possible to concentrate 100%, and the high solute rejection rate is also 100% concentrated in the absence of osmotic pressure difference.

In the present invention, the solute low selectivity membrane is a membrane having a selectivity lower than 1 and higher than 0, which generally corresponds to a nanofiltration membrane, but is not limited thereto.

In the present invention, when the target material is a solid, it is easy to crystallize according to temperature and pH, and is suitable for a material having high viscosity at high concentration. For liquids, alcohol for fuel may be a good application but is not limited to this.

In the present invention, the pH of the aqueous solution is 2-13, the temperature is the temperature at which water maintains the liquid (usually 0 to 100 ℃, preferably 15 to 50 ℃, more preferably 20 to 40 ℃) or more Or can be For example, mixtures with other solutes / solvents may deviate from the above temperatures.

In the present invention, as a solution introduced into the π-echolizer chamber to form an osmotic pressure between the feed chamber and the draw chamber, a concentrated aqueous solution transferred to the feed chamber, a solution that can be easily separated after use, and the like may be used. It is preferable to use an aqueous solution of the same composition as the concentrated aqueous solution transferred to the feed chamber.

In the present invention, the concentration using the osmotic pressure difference concentrator may be performed in a batch or continuous manner to maximize the effect.

The batch may be performed when there is no flow with both chambers and the external system, and the continuous may be performed when there is a flow with the external system.

In the present invention, the feed chamber and the π-equalizer chamber is characterized in that it is composed of a multi-stage.

In the present invention, the method of recovering the solute and the water from the aqueous solution further concentrated in the osmotic pressure difference concentrator is independently a commonly known multistage evaporation method, dialysis evaporation, pyrolysis method, sulfuric acid method, calcium method and input-split. cascade may be used, but is not limited thereto.

In the present invention, the concentration method further comprises the step of (d) maximizing the recovery of either solute or water using any one of the steps (i) to (iii) of step (c). It can be characterized.

In the present invention, the pressure-added forward osmosis (PRO) power generation, resource utilization and rare earth recovery process may be further included to increase the added value of the process.

In the present invention, it may further comprise a step of optimizing the material balance and the energy balance.

The present invention also relates to a method for separating a solvent and a solute from a solute-containing solution using the above concentration method.

In the present invention, the solute is a salt, the solvent may be characterized in that the water.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not to be construed as being limited by these examples.

Example 1 Recovery of Water and Solutes

1-1. Recovery method of water

When pressure is applied at 3% salt water, the flux of water can be easily obtained as Jw = Lp (ΔP-Δπ). As disclosed in Table 1 / Table 4, the osmotic pressure of 3% brine is 23.743 bar with a minimum energy of 0.659 kwh / m3. Recovery of water at 500 RO leaves 30 kg (solute rejection 100% home) and 470 kg water, leaving a concentration of 6%. The osmotic pressure of 6% is 50.467 bar and the energy required for reverse osmosis

Using the arithmetic mean of osmotic pressure of 3% and 6%, it is (23.743 + 50.467) /2*0.5/36=0.515 kwh.

1-2. How to recover water from recycle stream

In the recycle stream, energy is consumed for recycle energy and RO for water recovery. The energy associated with the recycle stream depends on the method, so for 100% recovery of water, 470 L is recovered and 0.515 * 0.470 / 0.500 = 0.484 kwh is added. Recycle energy is added here.

In case of discharging to saturated solution without recovering salt, 41.67kg of water and 15kg of salt are discharged twice. That is, 470-41.67 = 428.33 Kg is recovered. By the way, the second recycle with 6% solution has to be supplied with 235kg of water, so the recoverable amount is 193.33. Thus, the amount of water recovered by recycling twice is 386.66 kg. This amount is the amount recovered from ② RO unit of representative figure 1. 970kg-83.34kg = 886.66kg (= 500kg + 386.66kg). An important principle is that the amount of water recoverable in the second stream is 235 × 2 = 470 kg when the product stream returns to 3%, but otherwise the amount that can be recovered is reduced.

Table 4 calculates the osmotic pressure of 3% NaCl, the description of each column of the table is as follows.

# 1: w / w% is the weight ratio of water and salt. 3% brine consists of 970kg water and 30kg salt

# 2: Mole fraction (2 * NaCl / (total moles)) used for osmotic pressure calculation.

# 3: Osmotic pressure calculated using OLI_Analyzer software at each w / w%. (https://en.wikipedia.org/wiki/OLI_Aanlyzer)

# 4: Differential pressure is used to calculate the% osmotic pressure between each%.

# 5: The amount of energy required to produce one ton of water with an unchanged percentage of raw water at each concentration.

# 6: Volume 1 is the amount of water contained in each% solution based on 30 kg of salt.

# 7: Differential volume is the difference in volume between each section.

# 8: Differential energy amount for each section.

# 9: Accumulated # 8 The energy required from 6% to 26.47% is 1.7512-0.4750 = 1.2402.

As a result, it was found that 3% had a low concentration but a lot of water was included in the section, so that the differential energy was high, whereas after 25% of the high concentration, the pressure was high, but the water contained in the section had little effect.

Example 2 Flux with Concentration at Δπ = 0 (LMH, liters / (m2.h)

A sample (NaCl aqueous solution) is put in the apparatus as shown in FIG.

The membrane used in this example is RE2521-TL (Woongjin Chemical Co, Seoul, Korea; http: //www.csmfilter.com) Ltd, which is a thin-film composite type and the membrane is used in a negatively charged, polyamide, spiral-wound module. RO membrane. The permeability is 1.1m ³ / day and the effective area is 1.1m ² . 99% rejection at 1,500mg / L salt solution, 1.0MPa, maximum pressure is 4.14MPa, maximum flow rate is 1.36m ³ / hr, minimum flow rate (concentrate) is 0.23m ³ / hr. The maximum temperature is 45 ° C. and the pH is 3.0-10.0 and can withstand 2.0-11.0.

When the NaCl solution having the composition shown in Table 5 below was filled with 500 ml in the A and B chambers, the amount of permeation with time appeared as the weight of the B chamber and monitored by a computer. For NaCl, a conductivity meter (CM-31p, TOADKK, Japan) was used, and for VFA-Na, HPLC (YoungLin, Korea) was used (Table 5).

As shown in Table 5, the 1.5 to 3% portion has a linear relationship where the plus is above the critical pressure, but at subsequent concentrations it is proportional to (ΔP) ^α (C) ^β where α is 0 to 1 and β is -1 to 0 are displayed. The higher the concentration, the lower the flux and the higher the pressure. The maximum pressure was 40 bar.

Example 3: 100% Separation of Solute / Solvent Based on Feed Input-Split Cascade Process

As shown in FIG. 4, the process of the present invention is capable of producing an input stream of 3%, a water production system at the bottom, a saturated concentrated solution at the top or a salt thereof.

The 3% solution produces 500 L of pure water and enters the 6% chamber with 6%, 470 L water (total 500 kg solution). Here, the input-split method is used to separate 9% concentrate and 3% solution, 6% of which is a 9% chamber at the top, 3% of which produces 235 kg of raw water in the RO-2 unit, and the remaining 235 kg enters the chamber as Recycle. . 9 → 12 → 15 → 18 → 21 → 24 → 26.47% (sat.) And the diluted stream was recovered to 26.47% → 21% → 18 → 15 → 12 → 9 → 6 → 3 → 0 (pure) do.

This can be adjusted by using α (alpha: A) and θ (theta, T).

Calculating the assumption that 6% is 9% and 3%, A = 2, T = 1/3: A = feed chamber (FC) / equalizer chamber (EC), T = fraction of water moved from FC to EC. Feed input-split will allocate 2/3 of input to FC and the other 1/3 EC. T = 0.5 will move 1/3 (a half of FC) to EC. Then Water volume of FC will be 1/3 and that of EC will be 2/3. The concentration of EC will be 6% / (1-1 / 3) = 9% while 6% / (1 + 2 * 0.5) = 3%. In this way, dispensing can be done with minimal osmotic pressure difference between the two chambers. Ultimately the salt moves up the water down.

Example 4 Calculation of Energy Consumed in a Feed “Input-Split Cascade” System

1000 kg of 3% input is separated into a 6% mixed solution of 500 kg of pure water and 500 kg (30 kg of salt +470 kg of water) by the pure water recovery method of Example 1. This is the raw material of the Feed-Split Cascade system, which in turn separates the 9% and 3% (or 3.38%) product stream of the feed solution concentrated by the Feed-Split.

The input 6% brine solution 500kg represents the fraction of how much water is filtered through the product stream in the total feed solution in θ (“T” for convenience) and α (for convenience “A”) for the size ratio of the feed chamber / Product Chamber. If you want to make the product stream 9%, then 6% / (1-T) = 9% and T = 1/3. In order to minimize the pressure difference between the next two streams, the larger A is better, but for convenience, a low value of 3% is 3.38%, and the amount of water transferred from the 6% feed input stream to the 3.38% π-Eco-rigid stream is 176.79 kg. do. Calculating the average pressure difference as 30bar, the minimum energy required is 30 * 0.17679 / 36 = 0.1473kwh. For reference, the concentration of π-Eco-Laziza stream is 6% / (1 + 2.3204 * 1/3) = 3.38%.

Flux movement and energy consumption by solute concentration are 371 kg of total water moved through the membrane in feed input-split cascade. A total pressure of 0.309 Kwh is required at an average pressure difference of 30 bar, and two recycles are required to remove 30 kg of salt. The total energy required is 0.618kwh. The total minimum energy was found to be RO-1 energy + RO-2 energy + recycle (2 times) = 0.515 + 0.618 + 0.390 = 1.523 kwh. In practice, however, 9 steps of mixing and demixing occur from 3% to 26.47%. However, a considerable amount of water can be recovered in steps 1 and 2, which can be considered if not all of the water is recovered.

Example 5 Simulation of Feed Output-Split Counter Current (“Output-split CC”) Osmotic Pressure Difference Process

Unlike the input-split cascade of Example 4, there is no pressure release from feed-input to feed-output, resulting in less energy loss than input-split cascade.

In the output-split CC, the feed input is 6%, 470L, 30g in the osmotic pressure difference condensation process. As pressure is applied from the feed chamber, the water moves to the chamber by π-evaporator. The R on the right shows how much salt total flows from the feed chamber end stream to the product (draw) chamber. When 50% enters the product chamber, the concentration is 26.47% at the feed chamber end. However, at the end of the chamber, the π-echoarizer is 3.38% and the amount of water recovered is 428.33 kg. This is the amount when the product is a saturated solution.

At this time, the minimum energy to overcome the osmotic pressure when recycled once was calculated as = 0.38772 * 2 = 0.775 kwh.

The total energy is = 0.515 + 0.775 + 0.390 = 1.680 kwh.

Example 6 Separation of Water and Concentrated Salts in Output-Split CC

6-1. Desalination Process Balance and Minimum Energy

As disclosed in Table 6, it is assumed that the concentrated water of 3.0S and 3.0Ws (26.47% saturation) is Δπ = 0 in the upper and lower layers of the desalting tank, respectively. The beginning is “0” but at the end 0.5Ws of water moves from the upper water to the lower water, and as a result 0.5S (15g) of salt precipitates and is removed from the system, while it is in the form of 3.0S, 3.0Ws. Recycled. 0.5Ws filtered from the supernatant comes into the lower layer, and 3.0S of brine is crushed, and the concentration of 23.57% decreases the osmotic pressure difference of the upper layer into the lower layer (Δπ = 0).

Only 15g of salt and 41.67 of water are removed in one recycle, so two recycles are required for normal operation. At this time, the energy required is calculated as the average concentration (343.707-288.559) = 51.148; 51.148 * 0.04167 / 36 = 0.0638wkh / 15kg, 0.127kwh is required to remove 30kg, and the energy required to remove water with RO at 26.47%, 343.707 bar is calculated to be 343.707 * 0.08334 / 36 = 0.795 Kwh It became.

6-2. Calculate Feed Size and Energy Consumption

As seen in the desalination process above, it can be seen that the energy consumption varies greatly depending on the size of the sample entering the target RO apparatus. For example, if you remove 1 ton (100 liters of water and 30 kg of salt) from 100 tons of raw water, the minimum energy will be very small.

For example, if you make 1W of water in a 7S, 7W system, you get 3S to 7S, 6W and the concentration is 3.48%. The osmotic pressure difference is (27.849-23.743) = 4.106 bar. The required energy is 4.106 * 0.970 / 36 = 0.110kwh. This is almost 10%, considering that the theoretical energy required to obtain 1 m ³ of water is 1.14 kwh. In the above desalination tank, although the separation tank was used about three times larger than that of RO, the desalination tank by the large separation tank required a minimum energy of 0.795 kwh.

6-3. Calculation of minimum energy when salt is completely separated from water and salt in 1 ton of 3% brine

The energy consumption was only about 10% when a large separator was used at the feed input, but in fact energy consumption is highly related to the recovery rate. In the following example, 0.250m3 of water is recovered from the 1 ton 3% solution of Example 6-1 as the primary RO and the rest is recycled (0.970-0.250 = 0.720) and desalting is performed to satisfy the material balance. For Example 6-2, half of the water, 970 kg * 0.5 = 485 kg, is recovered to the primary RO and further recovered from the remaining recycle water (0.970-0.485 = 0.485). The F500 recovers 0.500 tonnes from the primary RO and the remainder from the recycle water (0.970-0.500 = 0.470).

The energy needed to obtain pure water and salt can be easily calculated, but the recycling energy is quite complicated and the methods vary greatly. The arithmetic mean at the beginning (26.47%) and the end of the “Output-Split CC” process is not exact but simple and the differences between the methods are shown in Table 7. The following processes all produce 30 kg of salt and 970 kg of water.

Note: RO-2 (0.432 ~ recycle energy, 0.483 ~ water recovery), WR = water per recycle

Note: Total energy 1.020 of F00 process (RO-1 process omitted, osmotic pressure concentrator directly)

In the table, the inputs of F250, F485, and F500 RO-1 are 3% brine and the concentration of the output according to the recovery degree of RO-1 entering the recycle stream. When the recovery was small, the concentration was low, and as in the F500, the recovery of 500L in RO-1 was confirmed to be 6%.

The first row is the energy required to recover pure water from 3% brine in the RO-1 unit, and the RO-2 is the energy consumed in the recycle unit. The last one is the desalination process from F250 of Example 2 (3.5S, 3.5Ws). Is the energy required.

The calculation of RO-2 was performed as follows. RO-2 input (top water) The difference in the output of the bottom water is multiplied by the amount of recycled water divided by 36 to get kwh. On the other hand, the energy difference was obtained by multiplying the pressure difference between feed-output (26.47%) and sub-water input (23.57%) by 41.67. In other words, the energy difference between the first and last energy was calculated from the recycling system, the arithmetic mean was calculated, and the total recycled water was multiplied to obtain a simple recycle energy. Obtain [Δπ at end (4% / 3%) * Q (0.470 / time) + Δπ at begin (26.47% / 23.57%)] / 36/2 * 2.

In the example calculation of RO-1 (4%), we use the mean. The average is (23.743 + 32.298) /2=28.020 RO-1 (F250) is 28.020 * 0.25 / 36 = 0.194 (where 28.02 is the RO-1 tank input (3%) and the output osmotic pressure difference of 4% 0.25m ³ RO-2 (F250) yields a cumulative amount of recycled energy [0.171 + 0.063] /2*2=0.234, which shows a significant effect not only on RO-1 but also on RO-2. The cost of water production of RO-2 is the Δπ process cost, plus 3% of the water production cost from the solution entering the raw water tank.The cumulative total of the three processes shows a low F250 of 1.236 but F485 or The F500 has significantly higher total energy requirements of 1.528 and 1.540, which is not significantly different from “Input-split Cascade” or “Output-split CC.” These values are based on the use of one ton of solute solution. Although the minimum energy is higher than that of a commercial process that recovers only 50% of raw water, the π-equalizing process using Δπ = 0 RO technology The recovery of salt at low pressure and 100% recovery of water can be significant.

Example 7 Application Comparison of Low Solute Selectivity σ Membranes in Input-Split Cascade and Output-Split CC.

7-1. Importance of pure and salt recovery using low solute selectivity membrane

As can be seen from the experimental results of Example 2, the higher the solution, the lower the flux, and the pressure cannot be increased indefinitely. Therefore, even if the solute selectivity (o) falls, it is necessary to use a membrane with a large flux to secure economic feasibility. The current study is preferably performed in the nano-filtration zone, not reverse osmosis.

Low selectivity membranes are applied to the input-split cascade and output-split CC to significantly improve the membrane flux and to save energy for the recycling process. Note that the current use of the RO process is one There needs 1kwh / m ³ to overcome the minimum osmotic pressure difference in the production of water per ton to overcome the osmotic pressure actually is 2kwh is consumed 2kwh, yet other processes in the osmotic process, the RO process, the total 4kwh Is known to be consumed. Considering that the cost of electric energy is $ 1 per ton of water, it is very important to reduce it to a little since 40% of the cost of water is assumed to be $ 0.1 / kwh.

Therefore, it is true that the above-mentioned osmotic pressure difference RO process requires additional electric power for the recycling of the brine, but it uses less raw material (now produces 1 ton of water from 2 tons of water and utilizes 50%) and also concentrates very high concentration (saturated concentration). , Or crystallization form), which is not only advantageous for power generation using FO, but also can be applied to the production of Lithium, Magnesium, Gold, uranium, etc. contained in a small amount of seawater as a more economical method than the conventional method. In other words, it can be advantageous in terms of utilization of concentrated effluents, which can be advantageous in terms of overall economic feasibility (RO water sales + forward osmosis (FO) generation using concentrated water + trace metal recovery).

7-2 Comparison of Applications of Low Solute Selectivity (o) Membranes in Feed Input-Split Cascade and Feed Output-Split CC.

In the Feed Input-Split cascade method of Table 8-1, assume that A = 2, T = 50% (50% of the top water, 1/3 of the total) is moving. For convenience, let's call the "top water" Product (Draw) stream a "bottom water." For σ = 1, the starting point concentration is 6% and the ending concentration is 11.32%. Even if 50% of the solvent is transferred from the upper water to the lower water, the concentration of the upper water is not 12% because only half of the solvent (water) moves, not half of the solution (salt + water). The upper water average is 8.66%, the lower water average is 4.55%, and the concentration difference is 4.12%. On the other hand, in case of σ = 0.5, 6% of the upper floors and 8.74% of the lower floors had an average of 5.29% and the difference was 2.08%.

Table 8-2 shows the case of Product-Split CC, which is the system result of A = 1 and T = 0.5. Finally, 15g of salt was discharged from the supernatant and recycled twice so that 30g was removed from the system. Here, when σ = 1 is 1%, the difference in concentration is 1%, whereas when σ = 0.5, the mean concentration difference is increased to 4.06%.

In the case of the input-split cascade, the osmotic pressure difference effect is shown near 3% of the start of the feed-stream in the case of the input-split cascade. Because it appears.

Comparing the two above, one method may be to input-split at first and then switch to output-split later. Using low solute selectivity membranes (eg σ = 0.5) can be seen to reduce membrane area or overall energy consumption than high selectivity membranes (eg σ = 1.0).

Therefore, in the input-split cascade process, the low membrane is used initially, and if the output-split CC is used, the membrane is initially used at σ = 0.8 ~ 0.9 and the concentration is considerably increased. When sigma was concentrated to sigma = 0.5 and 20% or more, it was preferable to use a film of sigma = 0.2 to 0.1, and it was confirmed that the combination of the two processes had a good effect.

Example 8: Without R1 (all recycled)

In Example 6, F500, F485, and F250 first examined 500L, 485L, and 250L recovery through RO in 970L water of 3% raw water. Then, let's consider recirculation of RO-1, which is the extreme condition, all zero.

Feed input 3%, 970 L + 30 kg salt and the recycle stream of the π-echolizer chamber will be 1.52% with 970 L + 15 kg salt water. The osmotic pressure of 3% is 23.743 bar and the osmotic pressure of 1.52% is 11.746 bar. The difference between the two osmotic pressure is 11.997 bar, the average is 17.744 bar. The energy of the feed input (3%, 970L) equalizer (1.52%, 970L) is 11.99 * 0.970 / 36 = 0.323 and the end (26.47%, 23.57%) 0.107, so the average (1/2) * 2 = 0.430. The energy required for RO was calculated to be 17.744 * 0.485 / 36 * 2 = 0.463 kwh.

The total energy is 0.430 + 0.463 + 0.127 = 1.020 kwh. The pressure difference at the input is 11.997 bar and the pressure difference at the input outlet (26.47%) / pi-Equalizer start point is 55.148 bar. High pressure in the middle process is not a problem because there are many solutions such as low σ membrane or input-split cascade.

As a result, if you get 1.5% output at 3.0% input, you can get water from the sea with only 20 ~ 30 bar pressure. When the π-echolizer (1.5%) is fed back into the feed of the osmotic pressure concentrator, the π-echolizer-output is 0.75% recycle energy ~ 0.157 + 0.107 (0.264) and RO-2 ~ 0.311 + 0.129 = 0.704. The pressure difference is 5.85 bar and the water pressure is 11.56 bar. Recirculation reduced the total minimum energy from 1.020 to 0.704. Reverse osmosis methods that can move from 20 to 30 bar will also be possible.

In summary, the current RO process (70 / 50bar.46,50%, 0.985), F250 (50 / 32.29bar, bar yield 100%, 1.236) F00-3% / 1.5% (35 / 23.74bar, yield 100%, 1.020 ), F00-1.5% / 0.75% (20 / 11.56 bar, 100%, 0.704 + 1.020 = 1.724), about 3 kwh, which adds 0.985 minimum energy to the current RO process, has an operating pressure of 70 => 50 = Examining how shrinking as it changes to> 35> 20 will yield appropriate optimization operations.

Since the calculation is easy to be mistaken, the specific method is as follows.

General calculation method (F250): (1) Calculate the water first. The RO-1 Feed input is always 3%. The RO-1 device output depends on how far you pull. If not pulled out, it is “0” and RO-1 output is 3%. It consists of RO-1 input (1 ton, 1000kg, 30S, 970W), so if you pull out 250W (250kg water), the RO-1 output will be 750kg solution, and 30S, (970-250) = 720W and 30 / (30+ 720) = 4%, which is the input to the Δπ-recirculation device. Energy calculation: Since the brine concentration changes from 3% to 4%, calculate the average osmotic pressure at the end of the start,

28.020 * 0.250 / 36 = 0.194 (Kwh). Do not confuse the pressure average and the pressure difference between the two concentrations. RO-1 uses only an average of 3% and 4%, later using both an average of 4% and 2.04% and pressure difference in recycle energy.

(2) Calculate recycle energy

In the Δπ-recirculation, all of the feed stream π-equalizer chambers (970 W during salt recovery) or a part (970-83.34 = 886.66 W excluding concentrated water) are returned to the E-chamber. That is 970W / 886.66W and salt 30S. After concentration, it is split in half and discharged to the outside, or the salt is recovered as crystals.

Let the input of the π-equalizer chamber be 15S, 41.67W (1/2 of the concentrated water component) and 23.57% (Example 6). The output is 15 / (15 + 720) = 2.04% since all the water is recovered. The pressure difference between 4% and 2.04% is 16.279 and the energy calculation is 16.279 * 0.720 / 36 = 0.3251kwh.

Since the energy at the π-equalizer-chamber input is 0.107, it must be averaged and rotated twice to remove 30S, resulting in (0.325 + 0.107) /2*2=0.432Kwh. (3) Calculate RO-2. In this case, 360W is produced at a time, so an average of 4% and 2.04% (24.150) is required. The water production energy produced in the second recycle is (32.298 + 16.019) /2*0.360/36*2=0.483, and the total is 0.194 + 0.433 + 0.483 + 0.127 = 1.236. Only 3% and 4%) are required, and the recirculation process requires both a pressure difference and an average, and the pressure difference can be used to calculate the recycle energy and the average can be used to calculate the water production energy of RO-2.

Example 9 Application of Fuel Free Alcohol to Osmotic Pressure Differential Technology

Ethanol for fuel is currently used in 99.5% or 99.6% purity. There is a thermal method (gas generates steam, electricity is used). According to the Renewable Fuels Association (March 06, 2016) in the United States, the minimum energy is 23,424 BTU / gal from Iowa WDG. If you change this to kwh / kg-fuel ethanol, you get 2.27kwh / kg-ethanol. Here, the concentration of up to 99.5% by applying an osmotic pressure difference RO technology will be considered.

Table 10 calculated the osmotic pressure of the alcohol by Lewis equation (eq.-4). Initially it goes up to 28 bar at 5% or 6010 bar at 99.50%. Unlike high pressures, high pressures have very low volume, which results in very low energy content. Like 3% -NaCl, most of the energy content is concentrated at low concentrations.

As with 3% NaCl, the energy required for concentration can be calculated. The energy required for concentration up to 5% 99.5% is 0.08819 kwh / kg, 10% → 99.5% is 0.0373kwh / kg and 7% → 99.5% is 0.04787kwh / kg. The minimum energy required to concentrate from 5% to 99.5% is 4.4093 kwh, which can be obtained by dividing this by the alcohol content. 5% is 4.4094 / 50 = 0.08819 kwh / kg.

We would like to compare it with a thermal enrichment process that is currently available. The website below is 2.27kwh / kg.

http: //www.ethanolproducer.coicles/13134/rfa-analysis-finds-improvement-of-corn-ethanol-net-energy-balance Accessed on July 17. 2016 Iowa lower energy consumption (WDG) = 23,428 BTU / gal = 23,428 / 3,412 BTU / (3.785 * 0.8) (kwh / kg)

On the other hand, ethanol, for example, to concentrate 7 (wt%) ethanol to 99.5% with RO, the minimum energy is 3.389 kwh, and additionally 3 kwh is added to 6.389 kwh / 70 kg = 0.091 kwh / kg.

The total heat energy is 2.27 / 0.091 = 24.94 times that of the osmotic process. In the above example, since the osmotic pressure of 99.6% is 6000 bar, the osmotic pressure difference technology can make the pressure level that we can handle (e.g. below 100 bar). Moreover, when the membrane is used, the azeotrope phenomenon between water and ethanol is also achieved. It can be said that it can be solved.

Example 10 Production of Li, Mg, Gold, Uranium in Osmotic RO Concentrated Water

The global desalination market is 60 million / d, according to 2016 (google image: desalination market accessed on 07-24-2016). An economic evaluation was conducted on the 65,000 ton / d seawater desalination plant in Gijang-gun, Busan, Korea. Economics compared the price of water at $ 1 per tonne based on the current international price of each element.

As disclosed in Table 11 below, most of them are so small that much less than the water sales price, Mg, salt and the like seems worth examining. The technology is at least 10 times more concentrated than seawater or 5 times more concentrated than current RO effluents, which may be advantageous over other processes.

The specific parts of the present invention have been described in detail above, and it is apparent to those skilled in the art that such specific descriptions are merely preferred embodiments, and thus the scope of the present invention is not limited thereto. something to do. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

The method of concentrating an aqueous solution by hydraulic pressure in a non-osmotic pressure difference state according to the present invention consumes less energy and can be concentrated until the maximum saturated aqueous solution concentration or the concentration of the solute is 100% without using an extraction solvent. There is an advantage that does not need to use a separate osmotic induction solution.

Claims (12)

1. A method of concentrating a solute-containing aqueous solution under a Δπ reduction condition comprising the following steps:

   (a) Concentrating the solute-containing aqueous solution using a non-osmotic pressure concentrator comprising a feed chamber and a π-echolizer chamber partitioned with a reverse osmosis membrane, using one or more of the following steps to feed the feed chamber and π- Forming a Δπ reduction condition between the equalizer chambers:

   (i) (Feed) Input-split cascade process;

   (ii) (Feed) Output-split counter-current process; And

   (iii) applying a nano filtration membrane;

   (b) recovering the concentrated solute-containing aqueous solution using another osmotic pressure concentrator or reverse osmosis.
2. The method of claim 1,

   (c) another stepless pressure difference concentrator of step (b) further comprises maximizing recovery of the solute using one or more of processes (i) to (iii).
3. The method of claim 1, further comprising concentrating the aqueous solution containing the solute to be concentrated using reverse osmosis pressure before the step (a).
4. According to claim 1, Another stepless pressure difference concentrator in the step (b),

   (i) transferring the solute-containing state or the first concentrated aqueous solution to the feed chamber of the osmotic pressure difference concentrator, and introducing a solution having the same osmotic pressure as the aqueous solution transferred to the feed chamber into the π-echoiser chamber, Forming an osmotic state between the π-echolizer chamber; And

   (ii) concentrating the aqueous solution by transferring the water of the aqueous solution to the π-echolizer chamber by applying a pressure of 10 to 100 atm to the feed chamber in an osmotic pressure-free state. How to.
5. The method of claim 1, wherein the input-split cascade process of step (a) transfers the secondary concentrated solute-containing aqueous solution to another osmotic pressure difference concentrator, half to a feed chamber and half to a π-echoiser chamber. Then concentrating the aqueous solution of the feed chamber at low pressure, and transferring the concentrated solute-containing aqueous solution to another osmotic pressure concentrator.
6. The method of claim 1, wherein the output-split counter-current process of step (a) sends a portion of the π-echolizer stream to the feed stream.
7. The process according to claim 1, wherein the step (iii) of step (a) is performed from the beginning when applied to the process (i), and the osmotic pressure difference and water ash of the feed chamber and the π-echolizer chamber when applied to the process (ii). A method for concentrating an aqueous solution, characterized in that the membrane is applied to the high solute selectivity in the front portion and the low membrane in the rear portion in consideration of the quantity.
8. The method of claim 2,

   and (d) recovering the solidified solute using thermal energy, electrical energy, or pressure in the concentrated solute-containing aqueous solution.
9. The method of claim 1, further comprising pressure delayed forward osmosis (PRO) power generation, resource utilization, and rare earth recovery processes to increase the added value of the process.
10. The method of claim 1, further comprising the step of optimizing the mass balance and the energy balance.
11. A method of separating a solvent and a solute from a solute-containing solution using the method of any one of claims 1 to 10.
12. The method of claim 11, wherein the solute is a salt or a liquid and the solvent is water.

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