CN212403765U - System device for concentrating saline water and extracting water by using organic aqueous solution - Google Patents

Abstract

The utility model discloses an utilize system's device of organic aqueous solution concentrated salt solution and extract water, including extraction separator, phase separator, rare extract liquid-water separator and separation water aftertreatment device, light salt water inlet pipe, circulation strong brine inlet pipe and dense extract liquid inlet tube are connected to the front end of extraction separator, and the rear end passes through the water outlet pipeline of rare extract liquid and connects phase separator, phase separator passes through pipe connection rare extract liquid-water separator, and rare extract liquid-water separator passes through pipe connection separation water aftertreatment device; the dilute extract-water separation device is also connected with a concentrated extract water outlet pipeline and a separation water outlet pipeline. The application is suitable for the concentration treatment of industrial sulfate-containing wastewater such as sulfate wastewater of a printing and dyeing mill and is also suitable for mixed wastewater containing monovalent salt and divalent salt, and besides the concentration of the divalent salt, part of the monovalent salt can be discharged from fresh water so as to be separated from the divalent salt, such as desulfurization wastewater of a power plant and the like.

Description

System device for concentrating saline water and extracting water by using organic aqueous solution

Technical Field

The utility model relates to a water desalination treatment technology in environmental protection technology and water treatment field especially relates to an utilize organic aqueous solution to draw water and utilize the concentration that increases salt solution and get rid of the device of salt with ionic effect from salt solution, concretely relates to utilize organic aqueous solution concentrated salt solution and draw the system's device of water.

Background

In water treatment, it is often necessary to remove a large amount of salt from water, such as by concentrating brine, for the purpose of reducing discharge or recycling such as industrial wastewater treatment, seawater desalination, etc. Commonly used methods are evaporation, reverse osmosis, chemical precipitation, and electrodialysis.

The principle of the evaporation method is mainly that the salt-containing solution is heated to the boiling point, and water is gradually taken out in the form of water vapor by using an air pump, or by using vacuum at a low temperature, or by using a carrier gas with low humidity at a low temperature. The water vapor is then cryogenically condensed into water in another vessel. The evaporation heat lost in the process can be recovered in the condensation process through heat exchange to a certain extent, and the energy consumption in the process is reduced. Typical evaporation methods include multiple effect evaporation, mechanical evaporation, flash evaporation, and the like. The evaporation process generally requires a heat source, or consumes electricity as a supplement to the energy source. When heat is used as a heat source, the energy consumption is relatively high. When electricity is used as an energy source, the energy consumption is reduced, but the price of the energy source is obviously increased, and the relative cost is higher. The advantage of evaporation is that it is less sensitive to salinity in the water, especially it is easier to treat water with high salinity such as seawater, which is not desirable for the low salinity water evaporation method.

Reverse osmosis is the desalination of salt by passing water through a membrane under pressure, some of the salt being unable to pass through the membrane because of the selectivity of the membrane. This method requires that the pressure must be higher than the osmotic pressure of the incoming water. When the salt content of water increases, resulting in too high osmotic pressure, reverse osmosis cannot continue. Reverse osmosis cannot treat high salt water and removes almost all ionic components of the water. In addition, the filter membrane is easy to be polluted and blocked, the filter membrane is frequently replaced, and a large amount of antifouling and blocking pretreatment causes the cost increase of reverse osmosis. Reverse osmosis is much less energy intensive than evaporation.

Precipitation is the process of adding chemical reagents to change the salt in solution into a precipitate or replacing it with a salt that is easy to handle. Whether chemical precipitation is feasible or not is determined by the chemical composition of salt in water, and has limitation, and the precipitable salt is in direct proportion to the dosage, the more salt is removed, the higher the dosage is, and excessive solid waste is added, so that the cost cannot be borne. Ion exchange is carried out by replacing the salt in the water with hydrogen ions, hydroxide ions, or other easily treated metal ions and acid ions through an ion exchange resin. Ion exchange can only treat water with relatively low salinity, and ion exchange resin can perform better in the aspect of removing heavy metal ions.

The electrodialysis method is that voltage is applied to two ends of the electrodialysis device to enable anions and cations in water to move in opposite directions, and the effect of separating salt from water is achieved. Similar to reverse osmosis, this process uses only electricity as a source of energy, but is inferior to reverse osmosis in terms of energy consumption and effluent quality. Since ion exchange membranes are used, ion exchange resins are also required for individual technologies, and therefore fouling of the process also occurs. Electrodialysis requires pretreatment as well as reverse osmosis depending on the chemical composition and conversion in the water. Generally similar to reverse osmosis, too high salinity cannot be treated. Unlike reverse osmosis, this process does not require pressure.

In the process of brine concentration, the concentration of salt is gradually increased, and certain components in the brine are precipitated out due to the fact that the solubility of the components is exceeded, so that concentration equipment is damaged, and concentration efficiency is reduced. Sometimes the precipitated component in the brine is calcium sulfate or calcium carbonate, and the calcium is removed by chemical softening and then concentrated, and the process needs adding a medicament. When the magnesium content of the water is high, the medicament is also consumed, resulting in excessive cost for softening. Ion exchange is a softening process that exchanges multivalent ions for monovalent ions, which removes calcium, magnesium, and other high valent ions. When the exchange resin is saturated, high-concentration monovalent ion water is needed for regeneration, so that the treatment cost is increased, and additional high-salt wastewater is generated.

Disclosure of Invention

To the problem that above-mentioned prior art exists, the utility model provides a can follow and draw water in the water that contains high valence anion salt, for example the sulfate, make the salt water highly concentrated and probably deposit and get rid of, utilize simultaneously with the low solubility cation in the ionic effect detach water, for example calcium, reach the system's device of demineralized water effect.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model discloses an utilize system's device of organic aqueous solution extraction water from salt solution, including light salt solution intake end and dense water play water end, still include extraction separator, phase separation device, rare extract liquid-water separator and separation water aftertreatment device, light salt solution inlet tube, circulation strong brine inlet tube and dense extract liquid inlet tube are connected to the front end of extraction separator, and the rear end passes through the water outlet pipeline of rare extract liquid and connects the phase separation device, the phase separation device passes through pipeline connection rare extract liquid-water separator, rare extract liquid-water separator passes through pipeline connection separation water aftertreatment device; the extraction separator is connected with a circulating strong brine water outlet pipe, and the circulating strong brine water outlet pipe is connected with a light brine water inlet pipe; the dilute extract-water separation device is also connected with a concentrated extract water outlet pipeline and a separation water outlet pipeline, and the concentrated extract water outlet pipeline is connected to the extraction separator.

Preferably, the extraction separator is provided with an exhaust pipeline, and the exhaust pipeline comprises concentrated brine exhaust, precipitate exhaust and the like.

The extraction separator can be a centrifugal extractor, and the heavy phase is close to the wall and the light phase is close to the central position according to the difference of gravity after centrifugation, so that the separation can be realized, and the continuous or intermittent operation can be realized; also in centrifugal extraction, brine (heavy fraction) enters near the center and extractant near the wall. The two parts flow in opposite directions, and are contacted during the flowing process to perform extraction. Strong brine flows out at the wall, and the extractant flows out at the center; the extraction separation can also be similar to the rectifying tower plate and multi-stage extraction.

Preferably, the separated water post-treatment device is connected with a water outlet pipe and a concentrated separated water outlet pipeline; the concentrated extraction liquid outlet pipeline is connected with a concentrated extraction liquid heat exchange device, and the separated water outlet pipeline is connected with a separated water heat exchange device and then connected with a separated water post-treatment device.

As a preferred scheme, the post-treatment device for the separated water can be connected with a water outlet pipe and a water outlet pipeline for the concentrated separated water; the concentrated extraction liquid outlet pipeline is provided with a concentrated extraction liquid heat exchange device, and the separated water outlet pipeline is connected with the separated water post-treatment device and then connected with the separated water heat exchange device.

Preferably, the diluted extraction liquid outlet pipeline is connected with a diluted extraction liquid heat exchange device.

As a preferred scheme, the dilute extract outlet pipeline can be divided into two paths, one path is connected with the separated water heat exchange device, the other path is connected with the concentrated extract heat exchange device, and then the two paths are combined into one path and then connected with the phase separation device.

Preferably, temperature changing devices are arranged on the dilute brine water inlet end and the circulating concentrated brine water outlet pipe. The temperature changing device can be add to the end of intaking of light salt solution, for example advance water heat exchanger, can add the temperature changing device on the circulation strong brine outlet pipe, for example circulation strong brine heat exchanger. The two temperature changing devices are not limited to heat exchangers, and for example, partial evaporation can be used to change the temperature of water.

The present application also provides a method for extracting water from brine using an organic aqueous solution using the system apparatus described above by directly contacting the organic aqueous solution (extract) with the brine to extract water from the brine, producing a diluted organic aqueous solution phase and a concentrated brine phase. The concentrated brine becomes concentrated brine drained after treatment. The diluted organic solution phase undergoes a phase separation upon warming, resulting in a concentrated organic solution phase and an aqueous phase. The water phase is cooled and post-treated to form water, and the concentrated organic solution phase is cooled and recycled to extract water in the inlet brine; when the organic aqueous solution is directly contacted with the brine, the brine is concentrated and part of cations, such as calcium in sulfate, are precipitated due to the homoionic effect, so that part of hardness in water is removed without adding a precipitant.

The method for concentrating brine and extracting water by using the organic aqueous solution specifically comprises the steps of feeding light brine, circulating strong brine and concentrated extract into an extraction separator for mixed extraction and separation, feeding dilute extract obtained by extraction and separation into a phase separation device for phase separation, then feeding the dilute extract into a dilute extract-water separation device to obtain concentrated extract and separated water, and feeding the concentrated extract obtained by extraction and separation into the extraction separator again; and sending the separated water into a separated water post-treatment device to obtain final produced water.

In the above method, a preferable scheme may be that the dilute brine is directly fed into the extraction separator after the temperature of the dilute brine is changed by the temperature changing device or without the temperature changing device, the circulating concentrated brine is directly fed into the extraction separator after the temperature of the circulating concentrated brine is changed by the temperature changing device or without the temperature changing device, the concentrated extract is fed into the extraction separator after the temperature of the concentrated extract is changed by the concentrated extract heat exchange device, and the separated water is fed into the separated water post-treatment device after the temperature of the separated water is changed by the separated water heat exchange device.

In the above method, a preferable scheme may also be that the dilute brine may be directly fed into the extraction separator after the temperature is changed by the temperature changing device or without the temperature changing device, the circulating concentrated brine may be directly fed into the extraction separator after the temperature is changed by the temperature changing device or without the temperature changing device, the concentrated extract is fed into the extraction separator after the temperature is changed by the concentrated extract heat exchange device, and the separated water is fed into the separated water post-treatment device for treatment and then is subjected to temperature change by the separated water heat exchange device to obtain final produced water. The temperature changing device can be a heat exchanger (heat exchange device), a heater, a cooling device and other devices capable of changing temperature.

In the above method, a preferable embodiment may be: and the dilute extraction liquid is sent into a phase separation device for continuous temperature rise after the temperature of the dilute extraction liquid is changed by a dilute extraction liquid heat exchange device.

Alternatively, the dilute extract may be divided into two parts: one part changes the temperature through a concentrated extract liquid heat exchange device, the other part changes the temperature through a separation water heat exchange device, the two parts are mixed and sent to a phase separation device for phase separation, and then the mixture is sent to a dilute extract liquid-water separation device.

The present application is based on the direct interaction of an organic aqueous solution and a brine solution, wherein the osmotic pressure of the organic aqueous solution is higher than that of the brine solution, and in order to achieve osmotic equilibrium, the solute and the solution will be transferred at the phase interface, and the phase with high osmotic pressure (organic extract) will absorb the water of the phase with low osmotic pressure (brine), so as to achieve the purpose of extracting water from the solution with low osmotic pressure (brine). That is, according to thermodynamic equilibrium, since the organic solute is not easily dissolved in brine and the salt is not easily dissolved in the organic aqueous solution, two phases are finally formed: one phase is an organic aqueous solution, with a small amount of salt dissolved. The other phase is brine, dissolving a small amount of organics.

In the application, the chemical components of the extracting agent can be compounds composed of one or more of alcohols, esters, ketones, ethers, sulfones, amides, amines, organic acids, sugars and amino acid structures. The molecular weight may be 50 to 100000, preferably 200-. The extractant can be a single compound as described above or a mixture of several different compounds as described above. The extractant in the application can be selected from water-soluble organic matters, and can be used in the application if the organic matters have a large number of hydrophobic groups, namely the extractant in the application can be selected from polymers (amphiphilic polymers) with amphiphilic functional groups, wherein the hydrophilic chain segments of the extractant are usually nonionic polyethylene glycol, polyvinyl ether, polyvinyl alcohol, polyethyleneimine, polyvinylpyrrolidone, polypropylene phthalamides and the like, and further comprise ionic polyacrylic acid, polystyrene sulfonate and the like; the hydrophobic segment comprises polypropylene oxide, poly-carbon alcohol (such as propylene glycol), polystyrene, polysiloxane, polybutadiene, polymethacrylene and the like; specifically, polyethylene glycol monolaurate, polyethylene glycol, polypropylene glycol, poly (N-isopropylacrylamide), etc., and copolymers and mixtures thereof may be mentioned. The terminal group and side chain of the compound can be modified according to actual requirements. The extraction liquid is mutually soluble with the aqueous solution by adjusting hydrophilic and hydrophobic components, and when the temperature is raised to a certain degree, the aqueous solution of the extraction liquid with certain concentration can generate phase separation to generate two separated phases. One phase is a concentrated extract and the other phase is a predominantly aqueous phase, with a small amount of extract dissolved.

In the present application, the contacting of the extract and brine may be a simple mixed contact, a convective contact, and a contact using a catalyst. The extraction separation of the mixed liquid of the extract and the brine (including light brine and strong brine) can be realized by natural settling separation, centrifugal settling separation and catalyst separation with different specific gravity. The extract and brine and any precipitate that may have formed may be separated by centrifugation and natural settling.

In this application, the concentrated salt solution of a part after extracting the concentration through the extraction device can be mixed with the influent water again as the concentrated brine of circulation and then contact with the extraction liquid, can increase the volume of salt solution in the contact on the one hand like this, can be better with the extraction liquid contact and reach the separation from the mixture after osmotic equilibrium. On the other hand, some salt can be precipitated in advance before the new inlet water is mixed with the concentrated extraction liquid, for example, a large amount of sulfate radicals in the concentrated brine can precipitate calcium in the inlet water, so that the softening effect is achieved. Besides extracting water, the extract can also selectively extract a part of certain salt, and the other salt is mainly remained in the brine, so as to achieve the purpose of separating salt.

The present application selectively precipitates calcium ions by recycling sulfate so that the treated water does not precipitate during the next concentration step (in the present application, the feed water is mixed with recycled sulfate water to form a mixed water. In addition, when the inlet water contains a certain amount of multivalent ions, the multivalent ions can be partially and selectively intercepted in the concentrated sulfate salt aqueous solution, and the monovalent ions in the inlet water partially and selectively flow out along with the produced water.

In the application, the concentrated extract is contacted with the mixed water in the next step in a cocurrent contact mode or a countercurrent contact mode. In the contact process, water and part of monovalent ions in the mixed water enter the concentrated extract liquor, and a small part of divalent ions enter the concentrated extract liquor to dilute the extract liquor to form diluted extract liquor. While most of the divalent ions, such as sulfate ions, will be trapped in the mixed water. At this time, the concentration of sulfate radicals in the mixed water is further increased to become concentrated brine, and further, precipitation of calcium sulfate is generated.

In this application, the strong brine and the diluted extract can be naturally separated or centrifugally separated depending on the difference of specific gravity. The separated strong brine will have a precipitate. A part of the concentrated brine and the precipitate can be directly discharged out of the system to maintain the balance of the system. A portion of the withdrawn brine may be treated, for example, by separating the precipitate, adding fresh brine, and refilling the system to maintain the equilibrium of the system. The other part of the concentrated brine becomes the circulating sulfate water which is mixed with the inlet water again.

In this application, the diluted extraction solution may be separated into a concentrated extraction solution and separation water by heating to form a phase separation. Small amounts of impurities in the separation water separated from the diluted extraction solution may be removed by other feasible means, such as reverse osmosis or nanofiltration. During the discharge of the produced strong brine, a filtering membrane can be adopted to intercept the extraction liquid, and the brine is discharged. The dissolved extract molecules can also be separated from the brine by reheating. Or the heating and filtering modes are matched for use.

In the present application, the extraction liquid and the extraction water may be separated by heating the phase separation.

In the present application, the temperature of the fluid can be changed by heat exchange to recover heat in the process, reduce heat consumption, or improve the efficiency of extracting water. The related heat exchange processes can be heat exchange provided by an external heat source/cold source, evaporation, condensation, a heat pump and phase change, and can also be heat exchange among different branches in the process due to different temperatures so as to reduce the energy consumption of the process.

The present application utilizes extraction fluid in direct contact with the target brine to extract water from the brine, forming concentrated brine and possibly precipitated, and diluted extraction fluid. The concentrated brine and the precipitate which may form may be discharged completely or partly. The diluted extract is subjected to a concentration process to form fresh water and a concentrated extract. The concentrated extract is returned to contact with new target brine to complete a process. The fresh water is further processed into product water. The separated water may be treated, for example by a nanofiltration membrane, and a substantial portion of the extract and divalent salts may be retained, resulting in a portion of the concentrated water. Most of the monovalent salt cannot be trapped and passes through the nanofiltration membrane together with water, and the monovalent salt becomes final water production of the system.

Meanwhile, in the method, by adopting a sulfate circulation mode, under the condition that the traditional softening precipitator is not added, calcium ions (softening water) in water can be effectively precipitated, and magnesium ions can not be precipitated and are separately removed or reserved. The process also allows separation of monovalent and divalent salts into different waters. For water containing divalent salts, it is also effective to concentrate to very high concentrations. The application can selectively separate monovalent ions and multivalent ions in water, such as magnesium ions. The separated multivalent ions and monovalent ions can be treated separately, the multivalent ions such as calcium ions form precipitates to be discharged, most of magnesium ions exist in circulating concentrated brine, and the monovalent ions mostly exist in the produced water, so that high-purity product salt can be obtained, and the added value of water treatment is increased.

The method can divide the inlet water into high-concentration divalent salt concentrated water and monovalent salt fresh water to produce water, so that the inlet water is efficiently desalted. The calcium ion content in the fresh water is greatly reduced, and the fresh water can be further subjected to reverse osmosis desalination with high efficiency and low cost to form real fresh water. The whole process does not need to add a traditional softener to remove calcium ions, so that the cost is saved. Also, separate treatment of the monovalent and divalent salts may generate additional salt product revenue. In addition, the energy source of the required heat exchanger can adopt low-cost waste heat from production. These advantages can reduce the cost of desalination of wastewater.

The application is suitable for the concentration treatment of industrial sulfate-containing wastewater such as sulfate wastewater of a printing and dyeing mill and is also suitable for mixed wastewater containing monovalent salt and divalent salt, and besides the concentration of the divalent salt, part of the monovalent salt can be discharged from fresh water so as to be separated from the divalent salt, such as desulfurization wastewater of a power plant and the like.

Drawings

FIG. 1 is a schematic diagram of a system architecture according to the present application;

FIG. 2 is a schematic diagram of another system configuration of the present application;

FIG. 3 is a schematic view of the dilute extract heat exchange device omitted from FIG. 1;

FIG. 4 is a schematic view of the dilute extract heat exchange unit omitted from FIG. 2;

FIG. 5 is a schematic diagram of another system configuration of the present application;

FIG. 6 is a schematic structural view of a system according to embodiment 6;

FIG. 7 is a schematic view of the system configuration of embodiment 7;

the figure is as follows: 1. brackish water (influent). 2, a dilute brine temperature changing device. 3, light saline. 4. And circulating the strong brine. And 5, concentrating the extract. And 6, an extraction separator. And 7, circulating the strong brine. 8 circulating strong brine temperature changing device. 9 diluting the extract. 10, a water separating and heat exchanging device. 11 a dilute extract liquid heat exchange device. 12 concentrated extract liquid heat exchange device. 13 diluting the extract. 14, phase separation device. 15 diluted extraction liquid-water separation device. 16, concentrated extract. 17 separating water, 18 separating water. 19 water separation post-treatment device. And 20, an external discharge pipeline. 21, post-treated separated water (effluent produced water). And 22, concentrated water (concentrated separated water). 23, a sedimentation treatment device. 24, light saline. 25, strong brine supplement

Detailed Description

The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application.

Example 1

Embodiments of the present disclosure provide a method for extracting water from brine by using an organic aqueous solution (extraction liquid), including:

the extract is brought into flowing contact with a brine and, in order to achieve phase equilibrium, solute and solvent water are transferred to the brine and extract, respectively, to form a new two-phase liquid. As the water is transferred in a large amount towards the extract, the concentration of the brine increases and the concentration of the extract decreases.

The low concentration extract is separated from the water in a manner to form product water and a concentrated extract.

And a part of the high-concentration brine is discharged after being treated, and a part of the high-concentration brine can be mixed with the low-concentration inlet water to form new inlet water.

The high concentration brine may be post-treated by heating to re-separate the dissolved extractant molecules from the brine. Selective filtration membranes can also be used to retain extractant molecules. Or heating and filtering may be used simultaneously.

Fig. 1 shows a flow chart of the above scheme. The dilute brine 1 may be changed in temperature by the dilute brine temperature changing device 2 as necessary to form the dilute brine 3, or may be directly changed into the dilute brine 3 without passing through the dilute brine temperature changing device 2. The dilute brine 3 may be further mixed with a circulating concentrated brine 4 (the circulating concentrated brine 7 is changed in temperature by a circulating concentrated brine temperature changing device 8 to become the circulating concentrated brine 4, or directly to become the circulating concentrated brine 4) as a new dilute brine as required, or may be changed to become a new dilute brine without any change. The fresh weak brine is in flowing contact with the concentrated extract 5, and can be in cocurrent mixed contact or in countercurrent mixed contact. The contacting may be by simple flow mixing, by increasing the efficiency of the contacting with a solid catalyst, or by more than one stage of contacting. During the contacting process, water and solute are separated by chemical potential difference between the two phases, and the water is transferred from the brine phase to the extraction liquid phase to form a concentrated brine phase and a dilute extraction liquid.

After the two phases have been contacted in the same direction, the two phases can be simultaneously passed to the extraction separator 6 and undergo a phase separation process to form two completely separated phases, wherein the resulting weak extract 9 flows out of the extraction separator 6. The produced concentrated brine can be completely discharged as discharged concentrated brine 20 directly or after treatment. In some cases, the other part of the concentrated brine except the discharged concentrated brine becomes the circulating concentrated brine 7, and the circulating concentrated brine 7 may be changed in temperature by the circulating concentrated brine temperature changing device 8 to become the circulating concentrated brine 4 or directly to become the circulating concentrated brine 4, and then mixed with the light brine 3 to change the concentration thereof to become new inlet water as described above. The phase separation can be achieved by contacting the two phases with a phase separation catalyst for coagulation and then natural settling separation by gravity, or by high speed rotation means (e.g., a centrifuge), centrifugation, or a combination of these methods.

Extraction water and phase separation occurs in the extraction separator 6 when the dilute brine phase and the concentrated extract liquid phase are brought into back mixing contact. The extraction separator 6 has at one end an inflow of the concentrated extract 5 and an outflow of the concentrated brine 7 and at the other end an outflow of the dilute extract 9 and an inflow of the dilute (weak) brine (3 and 4 mixed). The phase separation can be achieved by coagulation of the two phases by contact with a phase separation catalyst followed by natural settling by gravity, by centrifugation using a high speed rotating device such as a centrifuge, or by a combination of these methods. The concentrated brine phase can also be independently purified and separated to remove a small amount of impurities of the extractant. As above, the concentrated brine may be all reject concentrated brine 20, or reject concentrated brine 20 and recycle concentrated brine 7. The extractant may be added to the system as it is being mixed in flow, such as from the front end of the extraction separator 6.

The dilute extraction liquid 9 passes through a dilute extraction liquid heat exchange device 11 to become a dilute extraction liquid 13, or directly becomes the dilute extraction liquid 13, the dilute extraction liquid 13 can be further heated by a phase separation device 14 to generate a mixture with complete phase separation, and then separated water 17 and concentrated extraction liquid 16 are formed in a dilute extraction liquid-water separation device 15. During the step of the dilute extract 13 being converted into the separated water 17 and the concentrated extract 16, the dilute extract 13 may be a single phase or a mixture of water and concentrated extract resulting from partial phase separation, and then may be further heated by 14 to complete phase separation, the separated two phases, concentrated extract 16 and separated water 17, are formed in a dilute extract-water separator 15 (which may be a simple container or a container filled with a catalyst, so that the mixed solution of concentrated extract and separated water produced by the separation of the dilute extract flows slowly in the container and the separated two phases flow out respectively due to different specific gravities, or a centrifugal device, so that the concentrated extract and the separated water flow out respectively, or the catalyst may be a filler commonly used in a similar rectifying tower, which can increase the contact probability and area of the extract droplets with each other to improve the extraction rate) under the action of the catalyst, gravity and a centrifugal mode. Among them, the phase separation device 14 is a device capable of producing final phase separation by temperature rise, which is capable of providing a higher temperature to achieve further high temperature phase separation, and may be just a heater. In a solution of an extractant and water at a certain concentration, an aqueous solution of the extractant generates two separated phases due to the temperature rise during heat exchange and phase separation, one phase is an extraction liquid phase of the high-concentration extraction liquid, and the other phase is an aqueous phase of the low-concentration extraction liquid. There are losses in the process and in the recovery of heat, so the weak extract has no way to reach the temperature at which the thermal separation is carried out by recovering all the heat. After heat recovery, the dilute extract, for example, reaches 70 ℃ and some phase separation occurs, but not completely, at which time additional heat is injected by the phase separation device 14 to bring the extract to the separation temperature, for example, 90 ℃. Complete phase separation is achieved by the phase separation device 14, but the two phases which are mixed need to enter the dilute extract-water separation device 15 at this time to become two separated fluids, i.e., the concentrated extract and the separated water, and the dilute extract-water separation device 15 can be a gravity stratification device or a centrifugal device to realize the separation of the two phases. The concentrated extract 16 passes through the concentrated extract heat exchange device 12 to become concentrated extract 5 and enters the process again.

The separated water 17 passes through the separated water heat exchange device 10 to become separated water 18. The separated water 18 passes through a separated water treatment device 19 to become post-treated separated water 21 and concentrated water 22 generated by separated water treatment. The concentrated water 22 can be incorporated into the dilute brine 1, the dilute brine 3, the circulating concentrated brine 4, the concentrated extract 5, the circulating concentrated brine 7, the dilute extract 9, the dilute extract 13, the concentrated extract 16, the dilute extract-water separation device 15 and the separated water 17 according to the situation for recycling. The concentrate 22 may also be partially recycled and incorporated into the separated water 18. The post-treated separated water 21 and the concentrated water 22 can also change the temperature through heat exchange.

Example 2

Fig. 2 differs from fig. 1 in that the separated water 17 is first treated by a separated water post-treatment device 19, resulting in post-treated separated water 21 and concentrated water 22. The separated water 21 passes through the separated water heat exchange device 10 to generate separated water 18. The concentrated water 22 can be incorporated into the dilute brine 1, the dilute brine 3, the circulating concentrated brine 4, the concentrated extract 5, the circulating concentrated brine 7, the dilute extract 9, the dilute extract 13, the concentrated extract 16, the dilute extract-water separation device 15 and the separated water 17 according to the situation for recycling.

Example 3

One of the differences between fig. 3 and fig. 1 is that the separated water heat exchange means 10 and the dilute extract heat exchange means 11 of fig. 1 are combined into the separated water heat exchange means 10 of fig. 3, so that part of the dilute extract 9 can be heat exchanged with the separated water 17 to recover heat. Another difference is that the dilute extract heat exchange device 11 and the concentrated extract heat exchange device 12 of fig. 1 are combined into the concentrated extract heat exchange device 12 of fig. 3, and another part of the dilute extract 9 can exchange heat with the concentrated extract 16 to recover heat. Therefore, the separately added dilute extraction liquid heat exchange device 11 in the figure 1 can be omitted, and the heat obtained by cooling the separated water and the concentrated extraction liquid is effectively utilized.

Example 4

One of the differences between fig. 4 and fig. 2 is that the separated water heat exchange means 10 and the weak extract heat exchange means 11 of fig. 2 are combined into the separated water heat exchange means 10 of fig. 4, so that part of the weak extract 9 can be heat exchanged with the post-treated separated water 21 to recover heat. Another difference is that the dilute extract heat exchange device 11 and the concentrated extract heat exchange device 12 of fig. 2 are combined into the concentrated extract heat exchange device 12 of fig. 4, and another part of the dilute extract 9 can exchange heat with the concentrated extract 16 to recover heat. Therefore, the separately added dilute extraction liquid heat exchange device 11 in the figure 2 can be omitted, and the heat obtained by cooling the separated water and the concentrated extraction liquid is effectively utilized.

The heat exchange processes mentioned above can be implemented or removed according to specific needs. The heat exchange can be heat exchange provided by an external heat source/cold source, evaporation, condensation, a heat pump and phase change, or heat exchange between different branches in the process due to different temperatures so as to reduce the energy consumption of the process (fig. 3 and 4).

Example 5

Referring to fig. 5, the waste water obtained from the printing and dyeing mill after MBR and multi-stage nanofiltration to remove organic matter and monovalent salts is weak brine mainly containing sodium sulfate, and the extractant is P60 (polyethylene glycol monolaurate with a molecular weight of about 600). The percentage is mass concentration wt%.

The weak brine 1 (salt concentration about 5%) is mixed as feed water with unchanged temperature (normal temperature) with the circulating strong brine 7 (salt concentration about 20.5%) flowing out of the extraction separator 6 and the post-treated strong brine 22 (salt concentration about 1%, extractant concentration about 5%) flowing out of the separated water post-treatment device 19. The mixed brine and the low-temperature concentrated extract 5 with the extractant concentration of about 91 percent are further mixed in a flowing way, the generated mixed solution enters one end of the extraction separator 6 and slowly flows in the extraction separator 6 (a catalyst can be arranged to improve the extraction rate), and two separated phases, namely dilute extract and concentrated brine, are generated when the mixed solution flows to the other end of the extraction separator 6. Wherein, a part of the strong brine is treated and then is discharged as discharged strong brine 20; another portion is remixed with the feed water 1 as recycled brine 7.

The temperature of the dilute extract containing 75% of extractant and 0.02% of salt is raised to about 70 ℃ by a heat exchanger 11, and the dilute extract is further raised to about 95 ℃ by a phase separation device 14 and then enters a dilute extract-water separation device 15 to generate two separated phases, namely concentrated extract and separated water. Wherein, the concentrated extract containing 91 percent of extractant concentration is cooled to normal temperature (30-40 ℃) through a heat exchanger 12, and then mixed with the mixed brine again to flow into the extraction separator 6, thus completing one cycle.

The separated water is cooled to normal temperature (30-40 ℃) through a heat exchanger 10, and is further processed through a separated water processing device 19 (such as a nano-filtration device or ion exchange resin), the generated post-processed separated water 21 (containing trace amount of salt and an extracting agent) is product water which can be discharged for use, and concentrated water 22 (5% of the extracting agent and 1% of salt) generated by post-processing of the separated water. The concentrated water 22 can be mixed with 1 and then returned to the system for circulation.

According to the scheme of the embodiment of the application, water can be directly extracted from the saline water in a contact mode. Because the extraction solution and the salt solution are both in liquid phase, if precipitation occurs during the salt concentration process, the process is not greatly affected. In contrast, reverse osmosis requires a large amount of pretreatment to avoid precipitation. By selecting a particular extractant, the salt can be highly concentrated, or selectively concentrated. In addition, the separation of the extraction liquid and the water can use a low-cost heat source to further reduce the working cost.

Example 6

As shown in fig. 6, the dilute brine 1 as the feed water containing multivalent ions is cooled (to 10-40 ℃) by the dilute brine temperature changing device 2 to become the dilute brine 3. The dilute brine 3 and the circulating concentrated brine 4 (mainly concentrated brine solutions, such as sodium sulfate solution, potassium sulfate solution, magnesium sulfate solution and other soluble salts) are mixed, because the concentration of sulfate radicals in the circulating concentrated brine 4 is very high, the balance of calcium sulfate can be affected, and part of calcium in the inlet water can be precipitated in the form of calcium sulfate. The mixed water at this time is treated by the precipitation treatment device 23 (the precipitation treatment device 23 can be a sedimentation tank or a filter), and enters the extraction separation device 6 together with the concentrated extract 5 (the extractant is P60). In the extraction separation device 6, the concentrated extract can extract water in the brine to form a dilute extract 9 which flows out of the extraction separation device, and the brine is further concentrated due to water loss. During the further concentration of the brine, calcium sulphate precipitation may occur again. A part of the strong brine 7 enters the circulation again and changes the temperature through a strong brine temperature changing device 8 or directly becomes the strong brine 4. A portion of the concentrated brine is discharged with a possible precipitate. 25 may be make-up concentrated brine or a portion of the treated concentrated brine from discharge line 20 for re-injection into the extractive separation device 6 to maintain system equilibrium. The diluted extraction liquid 9 passes through a diluted extraction liquid heat exchange device 11 and a phase separation device 14, namely a heater, and is continuously heated to reach 95 ℃ to enter an extraction liquid-water separation device 15. Separated into a concentrated extract and separated water in an extract-water separation device 15. The concentrated extract 16 passes through a concentrated extract heat exchanger 12 to become a high-concentration extract 5 and enters an extraction cycle. The separated water 17 passes through the separated water heat exchanger 10 to become separated water 18. The separated water 18 can enter a separated water post-treatment device 19 to obtain purer water, namely the effluent water 21. The separated water post-treatment device 19 may be a nanofiltration device that traps a substantial portion of the divalent salts and extract residue to produce concentrated separated water 22. The concentrated separated water 22 may or may not exchange heat, and is mixed with concentrated brine supplement 25, light brine (influent water) 1, light brine 3, concentrated brine 4, concentrated brine 7, light brine 24, concentrated extract 5, dilute extract 9, extract-water separator 15, and concentrated extract 16 to circulate according to the circumstances.

Example 7

As shown in FIG. 7, the desulfurized wastewater from a thermal power plant containing 5% MgSO4, 1% NaCl and saturated CaSO4 (0.12%) was a dilute brine 1. The weak brine 1 is mixed with the strong separated water 22 and the circulating strong brine 4 in the extraction separation device 6 to form new brine without changing the temperature. The fresh brine is mixed with cooled concentrated extract 5 (extractant is P60) containing extractant with concentration of 91% in extraction separation device 6, and separated into dilute extract containing extractant with concentration of 77% and concentrated brine containing 19% MgSO4, 1.2% NaCl, and saturated CaSO4 (0.08%). During the production of concentrated brine, the saturation concentration of CaSO4 decreases and a portion of CaSO4 precipitates out and may be removed. Part of the produced strong brine can be discharged out of the extraction and separation device, and most of the strong brine is taken as circulating strong brine 4 to be mixed with inlet water to complete one-time circulation so as to maintain the balanced dosage of the strong brine of the system.

During extraction, the feed water containing 5% MgSO4, 1% NaCl was concentrated to a concentrated water of 19% MgSO4, 1.2% NaCl. On the one hand, the brine is highly concentrated, and on the other hand, the ratio of multivalent salt to monovalent salt is also significantly increased, and the main component in the concentrated brine is the multivalent salt MgSO 4. Meanwhile, a large amount of CaSO4 in the inlet water is precipitated greatly due to the increase of the sulfate radical concentration, and the water body is softened.

The dilute extraction liquid 9 is divided into two parts which respectively enter a concentrated extraction liquid heat exchange device 12 and a separation water heat exchange device 10 to recover heat of phase separation. The two parts flow out of a concentrated extract liquid heat exchange device 12 and a separation water heat exchange device 10 and then are gathered together to form a dilute extract liquid 13, and the dilute extract liquid is continuously heated to 95 ℃ by a phase separation device 14, namely a heater and then enters an extract liquid-water separation device 15. In the extraction liquid-water separation device 15, the separated concentrated extraction liquid 16 is cooled by the concentrated extraction liquid heat exchange device 12 to become concentrated extraction liquid containing 91% of the extractant concentration, and the concentrated extraction liquid can be mixed with the light brine to complete one cycle.

The separated water 17 flowing out of the extraction liquid-water separation device 15 is cooled by the dilute extraction liquid heat exchange device 10 to become separated water 18 containing 0.5% of the extracting agent and 1% of the salt. The separated water 18 passes through a separated water post-treatment device 19 (such as a nanofiltration membrane) to produce an effluent water 21 containing trace amount of extractant and 1% NaCl and a concentrated separated water 22. The concentrated separated water 22 is merged into the feed water to complete one cycle. The diluted extract has very little dissolved magnesium sulfate, so the magnesium sulfate in the separated water 17 is also very low, and the final effluent has a concentration similar to that of the inlet water 1 due to the high-efficiency barrier of the nanofiltration membrane of the separated water post-treatment device 19 to the magnesium sulfate and the low-efficiency barrier to the sodium chloride. Thus, the process effectively traps the magnesium sulfate in the concentrated brine effluent, while passing the sodium chloride through the process to the final effluent 21.

The application can be used for treating calcium ions in the power plant wastewater to prevent the pollution and blockage of pipelines caused by calcium sulfate deposition. At present, the power plant still adopts the traditional direct evaporation concentration to the treatment of calcium ion-containing wastewater, and calcium ions have formed precipitates and can cause extremely serious safety accidents if pipelines are dirty and blocked in the treatment, so that the calcium ions can be removed firstly through the application, and the traditional direct evaporation concentration mode is not suitable for treatment.

The above description is only for the preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (6)

1. The system device for concentrating brine and extracting water by using an organic aqueous solution comprises a dilute brine water inlet end and a concentrated brine water outlet end, and is characterized by further comprising an extraction separator (6), a phase separation device (14), a dilute extract-water separation device (15) and a separated water post-treatment device (19), wherein the front end of the extraction separator (6) is connected with a dilute brine water inlet pipe, a circulating concentrated brine water inlet pipe and a concentrated extract water inlet pipe, the rear end of the extraction separator is connected with the phase separation device (14) through a dilute extract water outlet pipeline, the phase separation device (14) is connected with the dilute extract-water separation device (15) through a pipeline, and the dilute extract-water separation device (15) is connected with the separated water post-treatment device (19) through a pipeline; the extraction separator (6) is connected with a circulating strong brine water outlet pipe, and the circulating strong brine water outlet pipe is connected with a light brine water inlet pipe; the dilute extract-water separation device (15) is also connected with a concentrated extract water outlet pipeline and a separation water outlet pipeline, and the concentrated extract water outlet pipeline is connected to the extraction separator (6).

2. The system for concentrating brine and extracting water from organic water solution as claimed in claim 1, wherein a precipitation treatment device (23) is provided on the weak brine inlet pipe.

3. The system for concentrating brine and extracting water from an organic water solution as claimed in claim 1, wherein said separated water post-treatment device (19) is connected to a water outlet pipe and a water outlet pipeline for the concentrated separated water; the concentrated extract water outlet pipeline is connected with a concentrated extract heat exchange device (12), and the separated water outlet pipeline is connected with a separated water heat exchange device (10) and then connected with a separated water post-treatment device (19).

4. The system for concentrating brine and extracting water from an organic water solution as claimed in claim 1, wherein said separated water post-treatment device (19) is connected to a water outlet pipe and a water outlet pipeline for the concentrated separated water; the concentrated extract water outlet pipeline is connected with a concentrated extract heat exchange device (12), and the separated water outlet pipeline is connected with a separated water post-treatment device (19) and then connected with a separated water heat exchange device (10).

5. A system for concentrating brine and extracting water from an aqueous organic solution according to claim 3 or 4, wherein the dilute extract outlet line is connected to a dilute extract heat exchanger (11).

6. The system for concentrating brine and extracting water from an organic aqueous solution according to claim 3 or 4, wherein the dilute extract outlet pipeline is divided into two paths, one path is connected with the separated water heat exchange device (10), the other path is connected with the concentrated extract heat exchange device (12), and then the two paths are combined into one path and then connected with the phase separation device (14).

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