TEMPERATURE SWING SOLVENT EXTRACTION FOR DESCALING OF FEEDSTREAMS

Abstract

Systems and methods of performing temperature swing solvent extraction (TSSE) descaling of produced water and desalination of high-salinity brines, e.g., those having a total dissolved solids (TDS) greater than about 250,000 ppm are capable of producing descaled water products including less than about 5% weight percent TDS. The brine/produced water feedstreams and combined with a solvent having temperature-dependent water solubility at a temperature T.sub.L. Water is extracted from the feedstream into the solvent to form a water-in-solvent extract component and a raffinate component, from which a solid phase can be precipitated as more water is portioned in the solvent and basicity increases. Heating of the water-in-solvent extract component reduces the solubility of the water therein, producing a biphasic mixture of dewatered solvent and descaled water that can be separated. Because these systems and methods do not require a phase change of water, these products are achieved with significantly higher energy efficiencies when compared to evaporation-based thermal methods.

Claims

1. A method of performing temperature swing solvent extraction (TSSE) desalination of high-salinity brines, comprising: providing a feedstream having a total dissolved solids greater than about 250,000 ppm; combining the feedstream with a solvent, wherein the solvent has temperature-dependent water solubility; bringing the combined feedstream and solvent to a temperature T.sub.L; extracting a liquid from the feedstream into the solvent to form a water-in-solvent extract component and a raffinate component at temperature T.sub.L, wherein the raffinate component includes an aqueous phase, a solid phase, or combinations thereof; separating the water-in-solvent extract component from the raffinate component; heating the water-in-solvent extract component to a temperature T.sub.H to produce a biphasic mixture of dewatered solvent and descaled water; and separating the dewatered solvent and the descaled water, wherein the descaled water includes less than about 5% weight percent total dissolved solids.

2. The method according to claim 1, wherein the feedstream includes brine, produced water, or combinations thereof.

3. The method according to claim 1, further comprising: cooling the dewatered solvent component from temperature T.sub.H; and combining the dewatered solvent component with the feedstream.

4. The method according to claim 1, further comprising: precipitating the solid phase; and sieving the solid phase from a liquid phase, the solid phase including one or more sealants from the feedstream.

5. The method according to claim 4, wherein the one or more sealants includes an alkali metal salts, Ca(OH).sub.2, CaCO.sub.3, FeCO.sub.3, Mg(OH).sub.2, MgCO.sub.3, MnCO.sub.3, SrCO.sub.3, BaSO.sub.4, CaSO.sub.4, MgSO.sub.4, SrSO.sub.4, or combinations thereof.

6. The method according to claim 1, wherein the solvent includes diisopropylamine (DIPA), N-ethylcyclohexylamine (ECHA), and N,N-dimethylcyclohexylamine (DMCHA), triethylamine (TEA), N-methylcyclohexylamine (nMCHA), N,N-dimethylisopropylamine (DMIPA), or combinations thereof.

7. The method according to claim 1, wherein T.sub.L is below about 20° C.

8. (canceled)

9. The method according to claim 1, wherein T.sub.H is between about 40° C. and about 80° C.

10. (canceled)

11. (canceled)

12. The method according to claim 1, wherein the feedstream to solvent ratio is less than about 15 mL/mol.

13. A method of performing temperature swing solvent extraction-stepwise release (TSSE-SR) desalination of hypersaline brines, comprising: providing a feedstream including a concentration of dissolved salts; combining the feedstream with one or more solvents, wherein the one or more solvents has temperature-dependent water solubility; bringing the combined feedstream and solvent to a temperature T.sub.1; extracting water from the feedstream into the solvent to form a water-in-solvent component and a raffinate component at temperature T.sub.1, wherein the raffinate component includes an increased concentration of dissolved salts; separating the water-in-solvent component from the raffinate component; bringing a previous water-in-solvent component produced via a previous separation step to at least one new temperature T.sub.N to produce a biphasic mixture of a subsequent water-in-solvent component and a subsequent raffinate component at temperature T.sub.N; separating the subsequent water-in-solvent component from the subsequent raffinate component; bringing a subsequent water-in-solvent component to a temperature T.sub.F to produce a biphasic mixture of dewatered solvent and descaled water; separating the dewatered solvent and the descaled water, and recycling the dewatered solvent to the combined feedstream and solvent, wherein the feedstream includes brines, produced waters, or combinations thereof.

14. (canceled)

15. (canceled)

16. (canceled)

17. A system of performing temperature swing solvent extraction (TSSE) desalination of high-salinity brines, comprising: a feedstream in fluid communication with a fluid source, the fluid source including a fluid having a total dissolved solids greater than about 250,000 ppm; a solvent source including one or more solvents with temperature-dependent water solubility; one or more extractors in fluid communication with the feedstream and the solvent source, the extractor including at least a first outlet and a second outlet; a water-in-solvent extract outlet stream in communication with the first outlet; a raffinate outlet stream in communication with the second outlet, wherein the raffinate outlet stream includes an aqueous phase, a solid phase, or combinations thereof; a separator in fluid communication with the water-in-solvent extract outlet stream, the separator including at least a third outlet and a fourth outlet; a descaled water component outlet stream in communication with the third outlet, the descaled water component including less than about 5% weight percent total dissolved solids; a dewatered solvent component outlet stream in communication with the fourth outlet; a temperature controller in communication with the one or more extractors and the water-in-solvent extract outlet stream; and a dewatered solvent recycle conduit in fluid communication with the dewatered solvent component outlet stream and the one or more extractors, the dewatered solvent recycle conduit configured to direct the dewatered solvent component outlet stream to the extractor wherein the one or more solvents include diisopropylamine (DHA), N-ethylcyclohexylamine (ECHA), and N,N-dimethylcyclohexylamine (DMCHA), triethylamine (TEA), N-methylcyclohexylamine (nMCHA), N,N-dimethylisopropylamine (DMIPA), or combinations thereof.

18. (canceled)

19. (canceled)

20. (canceled)

21. The method according to claim 13, wherein the steps of bringing a previous water-in-solvent component produced via a previous separation step to at least one new temperature T.sub.N to produce a biphasic mixture of a subsequent water-in-solvent component and a subsequent raffinate component at temperature T.sub.N, and separating the subsequent water-in-solvent component from the subsequent raffinate component, is repeated 2 or more times.

22. The method according to claim 21, wherein the temperature swing from T.sub.1 to T.sub.F is a continuous temperature gradient.

23. The method according to claim 13, wherein T.sub.1 is below about 20° C.

24. The method according to claim 23, wherein T.sub.1 is about 16° C.

25. The method according to claim 13, wherein T.sub.F is between about 40° C. and about 80° C.

26. The method according to claim 25, wherein T.sub.F is about 70° C.

27. The method according to claim 13, wherein the solvent includes diisopropylamine (DIPA), N-ethylcyclohexylamine (ECHA), and N,N-dimethylcyclohexylamine (DMCHA), triethylamine (TEA), N-methylcyclohexylamine (nMCHA), N,N-dimethylisopropylamine (DMIPA), or combinations thereof.

28. The system according to claim 17, wherein a first extractor is maintained at a temperature T.sub.L and the water-in-solvent extract outlet stream is heated to a temperature T.sub.H, wherein T.sub.L is below about 20° C. and T.sub.H is between about 40° C. and about 80° C.

29. The system according to claim 28, further comprising at least a second extractor in fluid communication with the first extractor via water-in-solvent extract outlet stream, wherein at least a second extractor is maintained at an intermediate temperature between T.sub.L and T.sub.H and the water-in-solvent extract outlet stream is heated to the intermediate temperature.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings show embodiments of the disclosed subject matter for the purpose of illustrating the invention. However, it should be understood that the present application is not limited to the precise arrangements and instrumentalities shown in the drawings, wherein:

[0018] FIG. 1 is a chart of a method of performing temperature swing solvent extraction (TSSE) descaling of a feedstream according to some embodiments of the present disclosure;

[0019] FIG. 2 is a chart of a method of producing a descaled water product according to some embodiments of the present disclosure;

[0020] FIG. 3 is a schematic representation of a system of performing TSSE, e.g., descaling/desalination of high-salinity brines/produced waters according to some embodiments of the present disclosure;

[0021] FIG. 4 is a schematic representation of performing temperature swing solvent extraction-stepwise release (TSSE-SR) desalination of hypersaline brines according to some embodiments of the present disclosure;

[0022] FIG. 5 is a chart of a method of producing a descaled water product according to some embodiments of the present disclosure;

[0023] FIG. 6A is a graph portraying water recovery and precipitated salt capabilities of methods and systems according to some embodiments of the present disclosure;

[0024] FIG. 6B is a graph portraying compositions of product water treated with methods and systems according to some embodiments of the present disclosure;

[0025] FIG. 7 is a graph portraying solids removal capabilities of methods and systems according to some embodiments of the present disclosure;

[0026] FIG. 8A is a graph portraying the mass fraction of DIPA and NaCl in the aqueous phase of a TSSE-SR experiment using DIPA and NaCl with three stepwise extractions; and

[0027] FIG. 8B is a graph portraying mass of the aqueous phase that was released at each intermediate temperature in a TSSE-SR experiment on 1.0 mol/L NaCl using DIPA with three stepwise extractions.

DETAILED DESCRIPTION

[0028] Referring now to FIG. 1, some embodiments of the present disclosure are directed to a method 100 of performing temperature swing solvent extraction (TSSE) descaling of a feedstream. In some embodiments, the feedstream includes one or more liquids that include an undesired component dissolved therein. In some embodiments, the undesired component includes one or more scalants, as will be discussed in greater detail below. The feedstream can be from any suitable source, e.g., existing in the natural environment, effluent from industrial processes, etc. In some embodiments, the feedstream includes brines, produced waters, or combinations thereof. In some embodiments, the feedstream includes high-salinity brine, produced water and flowback from oil and gas industry, fluegas desulfurization wastewater, inland desalination concentrates, landfill leachate, waste streams of zero/minimum liquid discharge operations, waste effluents from thermoelectric power plants, discharges of coal-to-chemicals facilities, etc., or combinations thereof. As used herein, the term “descaling” is used to refer to removal of the undesired components dissolved in the feedstream, i.e., scalants including minerals, metals, etc. In some embodiments, descaling of the feedstream includes removal of one more metal salts, e.g., desalination.

[0029] At 102, the feedstream is provided. As discuss above, in some embodiments, the feedstream includes produced water for removal of soluble salt scalants, e.g., produced water and flowback from oil and gas industry, fluegas desulfurization wastewater, inland desalination concentrates, landfill leachate, waste streams of zero/minimum liquid discharge operations, waste effluents from thermoelectric power plants, discharges of coal-to-chemicals facilities, etc., or combinations thereof. In some embodiments, the feedstream includes a hypersaline solution, e.g., 1M-5M+NaCl solutions, for desalination. In the some embodiments, the total dissolved solids (TDS) in the feedstream is greater than about 60,000 ppm, 70,000 ppm, 80,000 ppm, 90,000 ppm, 100,000 ppm, 110,000 ppm, 120,000 ppm, 130,000 ppm, 140,000 ppm, 150,000 ppm, 160,000 ppm, 170,000 ppm, 180,000 ppm, 190,000 ppm, 200,000 ppm, 210,000 ppm, 220,000 ppm, 230,000 ppm, 240,000 ppm, 250,000 ppm, 260,000 ppm, 270,000 ppm, 280,000 ppm, 290,000 ppm, 300,000 ppm, etc. In some embodiments, the one or more scalants include minerals, metals, etc., or combinations thereof. In some embodiments, the scalants include hydroxides, carbonates, phosphates, sulfates, etc. In some embodiments, the scalants include Ca(OH).sub.2, CaCO.sub.3, FeCO.sub.3, Mg(OH).sub.2, MgCO.sub.3, MnCO.sub.3, SrCO.sub.3, BaSO.sub.4, CaSO.sub.4, MgSO.sub.4, SrSO.sub.4, alkali metal salts, e.g., NaCl, or combinations thereof.

[0030] At 104, the feedstream is combined with one or more solvents. The one or more solvents have temperature-dependent water solubility, meaning that the solubility of water in the solvent decreases with an increase in temperature. In some embodiments, the solvent is basic. In some embodiments, the solvent includes one or more hydrophilic moieties in a mainly hydrophobic chemical structure. In some embodiments, the solvent is an amine solvent, e.g., a primary, secondary, or tertiary amine solvent. In some embodiments, the solvent includes diisopropylamine (DIPA), N-ethylcyclohexylamine (ECHA), and N,N-dimethylcyclohexylamine (DMCHA), triethylamine (TEA), N-methylcyclohexylamine (nMCHA), N,N-dimethylisopropylamine (DMIPA), or combinations thereof.

[0031] At 106, the combined feedstream and solvent are brought to a temperature T.sub.L. In some embodiments, the combined feedstream and solvent are maintained at temperature T.sub.L via any suitable heat source or cooling system, including external heat sources, recycled heat, heat exchangers, etc., as will be discussed in greater detail below. In some embodiments, T.sub.L is below about 20° C. In some embodiments, T.sub.L is below about 10° C. In some embodiments, T.sub.L is about 5° C. In some embodiments, the pH of the combined feedstream and solvent is increased, e.g., via the addition of a basic component, as will be discussed in greater detail below.

[0032] At 108, liquid from the feedstream is extracted into the solvent to form a water-in-solvent extract component. In some embodiments, as discussed above, the one or more solvents have temperature-dependent water solubility where water is more soluble in the solvent at T.sub.L than at higher temperatures. Without wishing to be bound by theory, at T.sub.L, water from the feedstream favorably interacts with the hydrophilic moieties in the chemical structure of the solvents. Thus, at T.sub.L, water favorably partitions from the feedstream into the solvent phase, leaving behind a raffinate component that retains the scalants from the liquid feedstream. In some embodiments, the raffinate component includes an aqueous phase, a solid phase, or combinations thereof.

[0033] In some embodiments, at 110, the solid phase is precipitated. In some embodiments, at 112, the solid phase is separated from a liquid phase, e.g., via sieve, membrane, etc. or combinations thereof The solid phase includes one or more scalants from the feedstream. As the feedstream comes in contact with the solvent, more and more water is extracted into the water-in-solvent extract component, increasing the concentration of scalants/salts in the raffinate component. When the solubility of the scalants/salts is reached, they can precipitate out to form a solid phase in the raffinate component. In some embodiments, the feedstream to solvent ratio is less than about 25.3 mL/mol, 20.2 mL/mol, 15 mL/mol, 10.1 mL/mol, 5.1 mL/mol, 2.5 mL/mol, etc. In some embodiments, the feedstream to solvent ratio is about 15 mL/mol. In some embodiments, the feedstream to solvent ratio is about 15.2 mL/mol. In some embodiments, the scalants in the solid phase include hydroxides, carbonates, phosphates, sulfates, etc. In some embodiments, the scalants in the solid phase include Ca(OH).sub.2, CaCO.sub.3, FeCO.sub.3, Mg(OH).sub.2, MgCO.sub.3, MnCO.sub.3, SrCO.sub.3, BaSO.sub.4, CaSO.sub.4, MgSO.sub.4, SrSO.sub.4, alkali metal salts, e.g., NaCl, or combinations thereof. In some embodiments, the solid phase separated at step 112 is recycled or sold as a product, e.g., for use in other processes/products.

[0034] At 114, the water-in-solvent extract component is separated from the raffinate component. In some embodiments, separation 114 occurs via a decanting process. At 116, the water-in-solvent extract component is heated to a temperature T.sub.H. In some embodiments, temperature T.sub.H is between about 40° C. and about 80° C. In some embodiments, temperature T.sub.H is about 70° C. In some embodiments, the water-in-solvent extract component is heated and/or maintained at temperature T.sub.H via any suitable heat source, including external heat sources, recycled heat, heat exchangers, etc. In some embodiments, the heat source is a low-grade thermal source. In some embodiments, the heat source is waste heat, renewable energy sources, e.g., wind, solar, hydrothermal, etc., or combinations thereof. Because the solubility of the water in the water-in-solvent extract component decreases when temperature increases, the temperature swing from T.sub.L to T.sub.H drives a phase separation in the water-in-solvent extract component. The result is a biphasic mixture of dewatered solvent, the water having come out of solution by the increase in temperature, and descaled water, the scalants having been previously removed by precipitation and/or removal of the raffinate component. At 118, the dewatered solvent is separated from the descaled water. In some embodiments, the descaled water includes less than about 15%, less than about 10%, or less than about 5% weight percent total dissolved solids. In some embodiments, the descaled water separated at step 118 is recycled or sold as a product for use in other processes. In some embodiments, the descaled water is further processed to further reduce total dissolved solids in the water, e.g., via a reverse osmosis process.

[0035] At 120, the dewatered solvent component is cooled from temperature T.sub.H. In some embodiments, the dewatered solvent component is cooled 120 from temperature T.sub.H to temperature T.sub.L. As will be discussed in greater detail below, in some embodiments, heat lost in the cooling of the dewatered solvent component (as well as the descaled water component) from T.sub.H can be recycled. In some embodiments, the heat is recycled in method 100, e.g., at step 116, or a separate process. At 122, the dewatered solvent component is combined with the feedstream, e.g., for use at one of steps 104, 106, or 108. In some embodiments, method 100 is a continuous or substantially continuous process. In some embodiments, method 100 is a semi-batch process. In some embodiments, method 100 is a batch or substantially batch process.

[0036] Referring now to FIG. 2, some embodiments of the present disclosure are directed to a method 200 of producing a descaled water product. In some embodiments, at 202, a volume of produced water is combined with one or more solvents. In some embodiments, the volume of produced water to solvent ratio is less than about 25.3 mL/mol, 20.2 mL/mol, 15 mL/mol, 10.1 mL/mol, 5.1 mL/mol, 2.5 mL/mol, etc. As discussed above, the one or more solvents have temperature-dependent water solubility. In some embodiments, the solvent includes aliphatic amines, cyclic amines, pyridines, piperidines, glycol ethers, or combinations thereof. In some embodiments, the solvent includes diisopropylamine (DIPA), N-ethylcyclohexylamine (ECHA), and N,N-dimethylcyclohexylamine (DMCHA), triethylamine (TEA), N-methylcyclohexylamine (nMCHA), N,N-dimethylisopropylamine (DMIPA), or combinations thereof. As discussed above, in some embodiments, the volume of produced water includes a plurality of soluble scalants, e.g., salts. In some embodiments, the volume of produced water includes produced water and flowback from oil and gas industry, fluegas desulfurization wastewater, inland desalination concentrates, landfill leachate, waste streams of zero/minimum liquid discharge operations, waste effluents from thermoelectric power plants, discharges of coal-to-chemicals facilities, etc., or combinations thereof. In some embodiments, the volume of produced water includes a hypersaline solution, e.g., 1M-5M+NaCl solutions, for desalination. In the some embodiments, the total dissolved solids in the feedstream is greater than about 60,000 ppm, 70,000 ppm, 80,000 ppm, 90,000 ppm, 100,000 ppm, 110,000 ppm, 120,000 ppm, 130,000 ppm, 140,000 ppm, 150,000 ppm, 160,000 ppm, 170,000 ppm, 180,000 ppm, 190,000 ppm, 200,000 ppm, 210,000 ppm, 220,000 ppm, 230,000 ppm, 240,000 ppm, 250,000 ppm, 260,000 ppm, 270,000 ppm, 280,000 ppm, 290,000 ppm, 300,000 ppm, etc. In some embodiments, the one or more scalants include minerals, metals, etc., or combinations thereof. In some embodiments, the scalants include hydroxides, carbonates, phosphates, sulfates, etc. In some embodiments, the scalants include Ca(OH).sub.2, CaCO.sub.3, FeCO.sub.3, Mg(OH).sub.2, MgCO.sub.3, MnCO.sub.3, SrCO.sub.3, BaSO.sub.4, CaSO.sub.4, MgSO.sub.4, SrSO.sub.4, alkali metal salts, e.g., NaCl, or combinations thereof.

[0037] At 204, the pH of the combined produced water and solvent is raised to produce an elevated-pH composition. In some embodiments, the pH is raised 204 by the solvent. In some embodiments, the pH is raised 204 via the addition of a supplemental basic component. Without wishing to be bound by theory, the solubility of scalants found in the produced water can be pH-dependent, e.g., with salts being less soluble in more alkaline conditions. Thus, as the pH of the solution increases, thermodynamic equilibrium is driven to induce formation of a solid phase.

[0038] At 206, a solid phase is precipitated from the elevated-pH composition, the solid phase including one or more of the scalants. At 208, the one or more scalants are separated from the elevated-pH composition, e.g., via sieving with a membrane. At 210, the elevated-pH composition is heated to a temperature T.sub.H to demix a descaled water component from a dewatered solvent component. At 212, the dewatered solvent component is removed to isolate a descaled water product. In some embodiments, the descaled water product includes less than about 15%, less than about 10%, or less than about 5% weight percent total dissolved solids.

[0039] At 214, the dewatered solvent component is cooled. In some embodiments, the dewatered solvent component is cooled 214 to temperature T.sub.L. As will be discussed in greater detail below, in some embodiments, heat lost in the cooling of the dewatered solvent component (as well as the descaled water component) from T.sub.H can be recycled. In some embodiments, the heat is recycled in method 200, e.g., at step 210, or a separate process. At 216, the dewatered solvent component is combined with the volume of produced water, e.g., for use in steps 202 and/or 204. In some embodiments, method 200 is a continuous or substantially continuous process. In some embodiments, method 200 is a semi-batch process. In some embodiments, method 200 is a batch or substantially batch process.

[0040] Referring now to FIG. 3, some embodiments of the present disclosure are directed to a system 300 of performing temperature swing solvent extraction, e.g., descaling/desalination of produced water/high-salinity brine. In some embodiments, system 300 includes a feedstream 302 in fluid communication with a fluid source 304. In some embodiments, fluid source 304 is from any suitable source, e.g., existing in the natural environment, effluent from industrial processes, etc. In some embodiments, fluid source 304, and thus feedstream 302, includes brines, produced waters, or combinations thereof. In some embodiments, fluid source 304 includes high-salinity brine, produced water and flowback from oil and gas industry, fluegas desulfurization wastewater, inland desalination concentrates, landfill leachate, waste streams of zero/minimum liquid discharge operations, waste effluents from thermoelectric power plants, discharges of coal-to-chemicals facilities, etc., or combinations thereof. In some embodiments, fluid source 304 includes a fluid having a total dissolved solids greater than about 60,000 ppm, 70,000 ppm, 80,000 ppm, 90,000 ppm, 100,000 ppm, 110,000 ppm, 120,000 ppm, 130,000 ppm, 140,000 ppm, 150,000 ppm, 160,000 ppm, 170,000 ppm, 180,000 ppm, 190,000 ppm, 200,000 ppm, 210,000 ppm, 220,000 ppm, 230,000 ppm, 240,000 ppm, 250,000 ppm, 260,000 ppm, 270,000 ppm, 280,000 ppm, 290,000 ppm, 300,000 ppm, etc.

[0041] In some embodiments, system 300 includes a solvent source 306. In some embodiments, solvent source 306 includes one or more solvents with temperature-dependent water solubility. As discussed above, in some embodiments, the solvent is basic. In some embodiments, the solvent includes one or more hydrophilic moieties in a mainly hydrophobic structure. In some embodiments, the solvent is an amine solvent, e.g., a primary, secondary, or tertiary amine solvent. In some embodiments, the solvent includes diisopropylamine (DIPA), N-ethylcyclohexylamine (ECHA), and N,N-dimethylcyclohexylamine (DMCHA), triethylamine (TEA), N-methylcyclohexylamine (nMCHA), N,N-dimethylisopropylamine (DMIPA), or combinations thereof.

[0042] In some embodiments, system 300 includes an extractor 308 in fluid communication with feedstream 302 and solvent source 306. In some embodiments, system 300 includes a plurality of extractors 308, e.g., arranged in parallel, arranged in series, or combinations thereof. In some embodiments, feedstream 302 and solvent from solvent source 306 are combined in extractor 308. In some embodiments, the ratio of feedstream 302 to solvent in extractor 308 is less than about 25.3 mL/mol, 20.2 mL/mol, 15 mL/mol, 10.1 mL/mol, 5.1 mL/mol, 2.5 mL/mol, etc. As discussed above, in some embodiments, feedstream 302 and solvent are combined at a temperature T.sub.L. In some embodiments, feedstream 302 and solvent are combined at different temperatures and brought to a temperature T.sub.L. In some embodiments, T.sub.L is below about 20° C. In some embodiments, T.sub.L is below about 10° C. In some embodiments, T.sub.L is about 5° C. At temperature T.sub.L, water from feedstream 302 favorably partitions into the solvent phase, producing a raffinate component that retains the scalants from the liquid feedstream. In some embodiments, the raffinate component includes an aqueous phase, a solid phase, or combinations thereof.

[0043] Further, as discussed above, upon combination feedstream 302 and solvent from solvent source 306, liquid from the feedstream is extracted into the solvent to form a water-in-solvent extract component. In some embodiments, extractor 308 includes at least a first outlet 308A. In some embodiments, extractor 308B includes a second outlet 308B. In some embodiments, a water-in-solvent extract outlet stream 310 is in communication with first outlet 308A. In some embodiments, a raffinate outlet stream 312 is in communication with second outlet 308B. In some embodiments, raffinate outlet stream 312 includes an aqueous phase, a solid phase, or combinations thereof. In some embodiments, extractor 308 includes one or more membranes 308C configured to isolate solid phase products, e.g., from the raffinate component. Membranes 308C can be of any suitable composition and pore-size to isolate the components of a particular solid phase. In some embodiments, membranes 308C are microporous, nanoporous, etc. In some embodiments, a membrane 308C is positioned in second outlet 308B. In some embodiments, raffinate outlet stream 312 includes an aqueous phase, any solid phase having been removed prior to exiting extractor 308, e.g., via 308B.

[0044] Extractor 308 can be of any suitable shape and volume to accommodate a desired volume of liquid, e.g., feedstream 302 in one or more solvents. In one exemplary embodiment, extractor 308 has a generally cylindrical shape, e.g., a liquid-liquid extraction column. Feedstream 302 is introduced at the top of extractor 108 and contacts solvent therein at temperature T.sub.L. The solvent progressively extracts water from the denser aqueous phase as it sinks toward the bottom. Scalants precipitate out and ultimately settle at the bottom of extractor 308, and are subsequently sieved off by membranes 302C as liquid streams, e.g., 308A and 308B, exit the extractor.

[0045] In some embodiments, system 300 includes a separator 314 in fluid communication with water-in-solvent extract outlet stream 310. Separator 314 is configured to demix a descaled water component from a dewatered solvent component. In some embodiments, separator 314 includes at least a third outlet 316 and a fourth outlet 318. In some embodiments, a descaled water component outlet stream 320 is in communication with third outlet 316 to remove the descaled water component from separator 314. As discussed above, in some embodiments, descaled water component outlet stream 320 includes less than about 5% weight percent total dissolved solids. In some embodiments, a dewatered solvent component outlet stream 322 is in communication with fourth outlet 318 to remove the dewatered solvent component from separator 314.

[0046] In some embodiments, system 300 includes a temperature controller 324A. In some embodiments, temperature controller 324A is in thermal communication with extractor 308 and/or water-in-solvent extract outlet stream 310, e.g., via a heat source, cooling system, etc. In some embodiments, temperature controller 324A is in thermal communication with raffinate outlet stream 312, separator 314, descaled water component outlet stream 320, dewatered solvent component outlet stream 322, dewatered solvent recycle conduit 326, feedstream 302, solvent stream, or combinations thereof. In some embodiments, temperature controller 324A is in thermal communication with water-in-solvent extract outlet stream 310 via separator 314. Temperature controller 324A is configured to maintain a predetermined temperature in extractor 308, e.g., temperature T.sub.L, as well as in water-in-solvent extract outlet stream 310, e.g., temperature T.sub.H. The heat input to system 100 can be supplied from low-grade thermal sources. In some embodiments, the heat is supplied from renewable energy sources, e.g., wind, solar, hydrothermal, etc., or combinations thereof.

[0047] In some embodiments, system 300 includes a pH controller 324B. In some embodiments, pH controller 324B is in communication with extractor 308. In some embodiments, pH controller 324B is in communication with water-in-solvent extract outlet stream 310, raffinate outlet stream 312, separator 314, descaled water component outlet stream 320, dewatered solvent component outlet stream 322, dewatered solvent recycle conduit 326, feedstream 302, solvent stream, or combinations thereof pH controller 324B is configured to maintain a predetermined pH in components of system 300, e.g., a lower pH in raffinate outlet stream 312, but a higher pH in extractor 108. In some embodiments, pH controller 324B increases the pH in a component of system 300 via addition of additional solvent, a basic component, or combinations thereof.

[0048] In some embodiments, system 300 includes a dewatered solvent recycle conduit 326 in fluid communication with dewatered solvent component outlet stream 322 and extractor 308. Dewatered solvent recycle conduit 326 is configured to direct the dewatered solvent component outlet stream 322 to extractor 308 for recycling, e.g., in embodiments where extractor 108 is operated in a continuous or semi-continuous manner. In some embodiments, system 300 includes one or more heat exchangers 328 In some embodiments, heat exchangers 328 are in thermal communication with water-in-solvent extract outlet stream 310, raffinate outlet stream 312, separator 314, descaled water component outlet stream 320, dewatered solvent component outlet stream 322, dewatered solvent recycle conduit 326, extractor 308, feedstream 302, solvent stream, or combinations thereof. Heat exchangers 328 are configured to recycle heat to reduce the overall energy cost of system 100. By way of example, in some embodiments, heat exchanger 328 extracts heat from dewatered solvent component outlet stream 322 and returns it to water-in-solvent extract outlet stream 310 to help demix the water and solvent components of that stream.

[0049] System 300 is advantageous for use both in front of plant and back of plant implementations. By way of example, in front of plant implementations, system 300 can be used to treat fluids existing in nature to decontaminate those fluids, isolate impurities for subsequent sale as a product, isolate impurities for use in industrial processes to produce other products, etc., or combinations thereof. By way of further example, in back of plant implementations, system 300 can be used to treat produced waters generated by industrial processes, either for reuse in the industrial processes, isolate byproduct impurities for subsequent sale as a product unto itself, decontaminate produced waters so as to provide less harmful wastes into the environment, etc., or combinations thereof.

[0050] Referring now to FIG. 4, some embodiments of the present disclosure are directed to a system 400 for desalinating a feedstream utilizing temperature swing solvent extraction-stepwise release (TSSE-SR). In some embodiments, system 400 includes a feedstream 402 in fluid communication with a fluid source 404. As discussed above, in some embodiments, fluid source 404 is from any suitable source, e.g., existing in the natural environment, effluent from industrial processes, etc. In some embodiments, fluid source 404, and thus feedstream 402, includes brines, produced waters, or combinations thereof. In some embodiments, fluid source 404 includes high-salinity brine, produced water and flowback from oil and gas industry, fluegas desulfurization wastewater, inland desalination concentrates, landfill leachate, waste streams of zero/minimum liquid discharge operations, waste effluents from thermoelectric power plants, discharges of coal-to-chemicals facilities, etc., or combinations thereof.

[0051] In some embodiments, system 400 includes a solvent source 406. As discussed above, in some embodiments, solvent source 406 includes one or more solvents with temperature-dependent water solubility. As discussed above, in some embodiments, the solvent is basic. In some embodiments, the solvent includes one or more hydrophilic moieties in a mainly hydrophobic structure. In some embodiments, the solvent is an amine solvent, e.g., a primary, secondary, or tertiary amine solvent. In some embodiments, the solvent includes diisopropylamine (DIPA), N-ethylcyclohexylamine (ECHA), and N,N-dimethylcyclohexylamine (DMCHA), triethylamine (TEA), N-methylcyclohexylamine (nMCHA), N,N-dimethylisopropylamine (DMIPA), or combinations thereof.

[0052] In some embodiments, system 400 includes an extractor 408 in fluid communication with feedstream 402 and solvent source 406. In some embodiments, system 400 includes a plurality of extractors 408, e.g., arranged in parallel, arranged in series, or combinations thereof. In some embodiments, feedstream 402 and solvent from solvent source 406 are combined, e.g., in a first extractor 408A. In some embodiments, the ratio of feedstream 402 to solvent in first extractor 408A is less than about 25.3 mL/mol, 20.2 mL/mol, 15 mL/mol, 10.1 mL/mol, 5.1 mL/mol, 2.5 mL/mol, etc.

[0053] In some embodiments, feedstream 402 and solvent are combined at a temperature T.sub.1. In some embodiments, T.sub.1 is below about 20° C. In some embodiments, T.sub.1 is about 16° C. In some embodiments, at the initial temperature, the solvent is hygroscopic and absorbs water while partially rejecting salt.

[0054] As discussed above, the water/solvent mixture separates into two immiscible liquid phases in first extractor 408A, a water-in-solvent component E.sub.1 and a raffinate component R.sub.1, that are physically separated. In some embodiments, the water-in-solvent component E.sub.1 and raffinate component R.sub.1 are separated via decanting, other suitable separation process, or combinations thereof. In some embodiments, the raffinate component at this stage, R.sub.1, is concentrated brine. In some embodiments, the water-in-solvent component at this stage, E.sub.1, is a mixture including solvent, water, small amounts of salts, etc.

[0055] In some embodiments, water-in-solvent component E.sub.1 is then heated or cooled, e.g., from T.sub.1, to a final temperature T.sub.F. In some embodiments, water-in-solvent component E.sub.1 is first heated or cooled to a second temperature, e.g., to T.sub.2, and then subsequently heated or cooled to T.sub.F. In some embodiments, the heating or cooling of E1 occurs in a series of extractors, as will be discussed in greater detail below. In some embodiments, the change to the second temperature induces the formation of an additional aqueous raffinate component, e.g., R.sub.2. Without wishing to be bound by theory, salts are polar, and thus salts remaining in water-in-solvent component E.sub.1 at T.sub.1 preferentially partition into aqueous raffinate component at the second temperature, e.g., into R.sub.2 at T.sub.2. In some embodiments, the additional raffinate component is then removed, leaving another water-in-solvent component, e.g., E.sub.2, with reduced salt content. In some embodiments, this subsequent water-in-solvent component E.sub.2 is heated or cooled to induce formation of subsequent water-in-solvent components and raffinate components, e.g., E.sub.3 and R.sub.3, as will be discussed in greater detail below.

[0056] Still referring to FIG. 4, in some embodiments, system 400 includes a plurality of extractors, e.g., 408A, 408B, 408C, etc. In some embodiments, water-in-solvent component is heated or cooled in a series of those additional extractors. In some embodiments, the plurality of extractors are in fluid communication with each other via one or more conduits. As discussed above, upon combination of feedstream 402 and solvent from solvent source 406, liquid from the feedstream is extracted into the solvent to form the water-in-solvent extract component, e.g., E.sub.1. In some embodiments, extractor 408, e.g., 408A, includes at least a first outlet 410A. In some embodiments, extractor 408 includes a second outlet 410B. In some embodiments, a water-in-solvent extract outlet stream 412 is in communication with first outlet 410A. In some embodiments, a water-in-solvent extract outlet stream 412, e.g., E.sub.1, is in communication with a subsequent extractor, e.g., 408B. In some embodiments, a raffinate outlet stream 414 is in communication with second outlet 410B. In some embodiments, raffinate outlet stream 414 includes an aqueous phase, a solid phase, or combinations thereof.

[0057] In some embodiments, the heating/cooling of the water-in-solvent component and removal raffinate component are performed one or more times, i.e., there are one or more “stages” of mixture heating in and raffinate component removal from a series of extractors, 408A, 408B, 408C, etc., via a series of water-in-solvent extract outlet streams 412 to communicate water-in-solvent extract component, e.g., E.sub.1, E.sub.2, E.sub.3, etc., from extractor to extractor and a series of raffinate outlet streams 414 to remove raffinate components, e.g., R.sub.1, R.sub.2, R.sub.3, etc., from each extractor. In some embodiments, the heating/cooling of the water-in-solvent component and removal raffinate component are performed a plurality of times. In some embodiments, water-in-solvent component E.sub.1 is heated or cooled, e.g., from T.sub.1, to at least one intermediate temperature T.sub.N. In some embodiments, and as discussed above, T.sub.N is chosen so that it induces the formation of an aqueous raffinate component, R.sub.N. Salts remaining in the mixture at T.sub.N preferentially partition into R.sub.N. R.sub.N is then removed, leaving the extract, E.sub.N. In some embodiments, E.sub.N is then heated or cooled to another intermediate temperature T.sub.N, forming yet another raffinate component R.sub.N and another water-in-solvent component E.sub.N, which are then separated, and so on. R.sub.N stages include a small portion of the water remaining in the mixture but are concentrated in salts. Experiments have shown that R.sub.N aqueous phases can be more concentrated than the first aqueous phase, R.sub.1, or the feedstream 402. Removing R.sub.N from the desalination process decreases the final product water salinity, thus producing higher quality product water.

[0058] In some embodiments, any number of heating or cooling stages to intermediate temperatures T.sub.N can be used until finally the water-in-solvent component E.sub.N arrives at final temperature T.sub.F. In some embodiments, the temperature swing from T.sub.1 to T.sub.F can be accomplished as a series of discrete temperature steps. In some embodiments, the number of heating or cooling stages to intermediate temperatures T.sub.N is greater than 1. In some embodiments, the number of heating or cooling stages to intermediate temperatures T.sub.N is greater than 2. In some embodiments, the number of heating or cooling stages to intermediate temperatures T.sub.N is greater than 3. In some embodiments, the number of heating or cooling steps to intermediate temperatures T.sub.N is greater than 5. In some embodiments, the number of heating or cooling steps to intermediate temperatures T.sub.N is greater than 10. In some embodiments, the temperature swing from T.sub.1 to T.sub.F can be accomplished as a continuous temperature gradient, e.g., in a single extractor or a series of extractors.

[0059] In some embodiments, extractor 408, e.g., 408A, includes one or more membranes 416 configured to isolate solid phase products, e.g., from the raffinate component. In some embodiments, a membrane 416 is positioned in second outlet 410B. Membrane 416 can be of any suitable composition and pore-size to isolate the components of a particular solid phase. In some embodiments, membrane 416 is microporous, nanoporous, etc. In some embodiments, raffinate outlet stream 414 includes an aqueous phase, any solid phase having been removed prior to exiting extractor 408, e.g., via 410B, etc.

[0060] In some embodiments, system 400 includes a separator 418 in fluid communication with a water-in-solvent extract outlet stream 412. Separator 418 is configured to demix a descaled water component from a dewatered solvent component. In some embodiments, separator 418 includes at least a third outlet 420 and a fourth outlet 422. In some embodiments, a descaled water component outlet stream 424 is in communication with third outlet 420 to remove the descaled water component from separator 418. As discussed above, in some embodiments, descaled water component outlet stream 424 includes less than about 5% weight percent total dissolved solids. In some embodiments, a dewatered solvent component outlet stream 426 is in communication with fourth outlet 422 to remove the dewatered solvent component from separator 418. In some embodiments, at least a portion of dewatered solvent component outlet stream 426 is recycled back to extractors 408, e.g., via solvent source 406

[0061] Additional aspects from system 300 not explicitly discussed with respect to system 400, e.g., temperature controller 324, heat exchangers 328, etc., may also be configured for use with system 400.

[0062] Referring now to FIG. 5, some embodiments of the present disclosure are directed to a method 500 of performing temperature swing solvent extraction-stepwise release (TSSE-SR) desalination of hypersaline brines. As discussed above, in some embodiments, the feedstream includes brines, produced waters, or combinations thereof. In some embodiments, the feedstream includes high-salinity brine, produced water and flowback from oil and gas industry, fluegas desulfurization wastewater, inland desalination concentrates, landfill leachate, waste streams of zero/minimum liquid discharge operations, waste effluents from thermoelectric power plants, discharges of coal-to-chemicals facilities, etc., or combinations thereof. At 502, a feedstream including a concentration of dissolved salts is provided. At 504, the feedstream is combined with one or more solvents. As discussed above, in some embodiments, the one or more solvents has temperature-dependent water solubility. In some embodiments, the solvent includes aliphatic amines, cyclic amines, pyridines, piperidines, glycol ethers, or combinations thereof. In some embodiments, the solvent includes diisopropylamine (DIPA), N-ethylcyclohexylamine (ECHA), and N,N-dimethylcyclohexylamine (DMCHA), triethylamine (TEA), N-methylcyclohexylamine (nMCHA), N,N-dimethylisopropylamine (DMIPA), or combinations thereof. At 506, the combined feedstream and solvent is brought to a temperature T.sub.1. In some embodiments, T.sub.1 is below about 20° C. In some embodiments, T.sub.1 is about 16° C. At 508, water is extracted from the feedstream into the solvent to form a water-in-solvent component and a raffinate component at temperature T.sub.1. As discussed above, the raffinate component includes an increased concentration of dissolved salts. At 510, the water-in-solvent component is separated from the raffinate component. At 512, a previous water-in-solvent component produced via a previous separation step is brought to at least one new temperature T.sub.N to produce a biphasic mixture of a subsequent water-in-solvent component and a subsequent raffinate component at temperature T.sub.N. At 514, the subsequent water-in-solvent component is separated from the subsequent raffinate component. In some embodiments, steps 512 and 514 are repeated 2 or more times. At 516, a subsequent water-in-solvent component is brought to a temperature T.sub.F to produce a biphasic mixture of dewatered solvent and descaled water. In some embodiments, T.sub.F is between about 40° C. and about 80° C. In some embodiments, T.sub.F is about 70° C. In some embodiments, the temperature swing from T.sub.1 to T.sub.F is a continuous temperature gradient. At 518, the dewatered solvent and the descaled water are separated. At 520, the dewatered solvent is recycled to the combined feedstream and solvent.

EXAMPLE

[0063] Continuous operation of systems and methods of the present disclosure were simulated by semibatch experiments with repeated extraction cycles, using DIPA as the solvent and 5.0 M NaCl solution as the hypersaline feed. To simulate solvent regeneration in continuous operation, the DIPA solvent was preloaded with DI water at about 6.4 w/w % and consecutively reused in three repeated TSSE cycles. 1.5 mL of a fresh brine (5.0 M NaCl) was introduced into 60 g of DIPA solvent in each extraction cycle to achieve a brine to solvent ratio of 2.5 mL/mol. The precipitated solids were sieved off with a microporous membrane under vacuum filtration and then weighed after drying. The product water collected from each extraction cycle was weighed to evaluate water recovery and analyzed for NaCl and solvent residue concentrations.

[0064] Referring now to FIGS. 6A-6B, water recovery, Y, and salt precipitated, P.sub.salt, of each extraction cycle were evaluated to examine recyclability of the systems and methods of the present disclosure. Water recovery is defined as the weight percent of the product water relative to the initial brine feed. High Y of 91.2, 95.8, and 95.9% were obtained for the 1st, 2nd, and 3rd cycles, respectively. Measured water recoveries were marginally below 100%, even though all the water was extracted from the brine feed in each cycle. Without wishing to be bound by theory, this discrepancy is mainly attributed to conservative sampling of the product water during separation from the biphasic mixture to avoid contamination by the solvent and slight undersaturation of the solvent in the 1st cycle. Y remained practically constant when the solvent was reused for the 2nd and 3rd cycles, indicating that ability of the solvent to extract water from the hypersaline feed is preserved. Almost all the salt in the 5.0 M NaCl brines precipitated out after water was extracted by the solvent and high P.sub.salt of ≈91, 90, and 91% were maintained in the 1st, 2nd, and 3rd extraction cycles, respectively. At the end of the last cycle, the DIPA solvent was measured to hold ≈6.5 w/w % water, effectively identical to the initial water content, and thus, further highlighting solvent recyclability in continuous operation.

[0065] The product water quality in repeated extraction cycles was assessed for salt concentration and solvent residue content. NaCl concentrations in the product water from each extraction cycle were 0.26, 0.31, and 0.29 M. The product water salt concentrations are markedly lower than the hypersaline feed of 5.0 M NaCl brine (93.8-94.8% reduction) and the amount of salt in the product water corresponds to 4.3, 5.2, and 5.0 w/w % relative to NaCl in the initial brine. Solvent residues in the product water were comparable at about 0.2 mol/L between the extraction cycles investigated.

[0066] Osmotic pressure reductions of 93.1-93.9% were also achieved. With substantially lowered TDS concentration and osmotic pressure, the desalted product water can be further polished using conventional techniques, such as reverse osmosis, for post-treatment with much less energy demand and fewer technical constraints, to yield a fit-for-purpose reuse stream and even fresh drinking water. The trace amount of solvent residues can also be recovered from the product water and returned to the cycle to curtail solvent loss.

[0067] Referring now to FIG. 7, the potential of the systems and methods of the present disclosure was further evaluated with an actual field sample. Hypersaline feed was prepared by evaporative concentration of RO effluent from the San Luis plant, CA, which desalinates irrigation drainage water of San Joaquin Valley to reach TDS concentration of≈295,000 ppm, i.e., approximately equivalent to 5.0 M NaCl brine. Extraction of all the water from the brine sample precipitated≈85.2% of the dissolved solids, which were removed by filtration. Product water TDS concentration was substantially reduced by—88.8% relative to the feed brine, from 295.4 g/L to 33.1 g/L. Total organic carbon (TOC) concentration of the product water (0.27 mol/L) was comparable to those obtained from semibatch TSSE-ZLD experiments with 5.0 M NaCl solution as brine feed, which had no initial organic content, indicating that TOC in the product water is mostly attributable to the solvent that has partitioned to the aqueous phase.

[0068] Referring now to FIGS. 8A-8B, in an exemplary embodiment, a diisopropylamine (DIPA)-water-sodium chloride (NaCl) TSSE-SR desalination system was constructed. Experiments were performed using 100.0 g of DIPA mixed with 100.0 g of 5.6 wt % NaCl.sub.(aq) solution (1 mol/L NaCl solution). Performing multiple releases, with T.sub.1=16° C., T.sub.2=22° C., T.sub.3=31° C., T.sub.4=35° C., T.sub.F=T.sub.5=70° C. produced a final product water, R.sub.5, with 0.30 wt. % NaCl. A comparison TSSE system using the same feed and outer operating temperatures without multiple release steps produced water with 0.76 wt. % NaCl. Without wishing to be bound by theory, the stepwise release process was responsible for a greater than factor-of-two decrease in salt contents.

[0069] It is apparent that the intermediate aqueous phases, performed at 22° C., 31° C., and 35° C., included substantially higher concentrations of salt than the final product water (see FIG. 8A). These intermediate aqueous phases were only a small portion of the overall mass of product water (see FIG. 8B). By removing the intermediate aqueous phases from the salt was removed, leading to superior quality product water.

[0070] Methods and system of the present disclosure are advantageous to treat feedstreams with high total TDS. Even feedstreams with TDS approaching 300,000 ppm can be treated, with final concentrations having less than 5% total dissolved solids. These results are achieved without the high-grade thermal energy requirements associated with evaporative phase change properties, i.e., steam that is>100° C. Temperature swing solvent extraction is uniquely suited for the desalination of hypersaline brines, a segment of intensifying environmental importance but not accessible by RO and handicapped by intrinsically poor energy efficiencies of evaporative methods. The technology is not restricted by feed solution properties, unlike membrane-based RO with hydraulic/osmotic pressure limitation. Because TSSE does not require a phase change of water, the penalizing energy cost associated with the enthalpy of vaporization is sidestepped and significantly higher energy efficiencies are attainable. As only moderate temperatures are needed (<70° C. in this study), the heat input can be supplied by low-grade thermal sources such as industrial waste heat, shallow-well geothermal heat, and low-concentration solar collectors, further enhancing the sustainability of TSSE. Other solvents with different chemical structures and properties can yield better performances to further expand the prospects of TSSE for energy-efficient and cost-effective desalination of high-salinity brines.

[0071] Among the solvents, DIPA exhibited the highest water extraction efficiency whereas ECHA and DMCHA produced water with the lowest salt content and solvent residue content, respectively. Specific performance objectives, such as, high water extraction efficiency, high salt removal, and low solvent loss, can be achieved by rational solvent selection. High water recovery>50% was demonstrated for TSSE desalination of 1.5 M NaCl brine in semi-batch experiments with multiple extraction cycles, highlighting the potential for a scaled-up continuous process. Substantial energy savings over conventional methods were achieved, drastically improving sustainability and enhancing economic feasibility. In some embodiments, the methods and systems of the present disclosure are applied to desalination/dewatering/reuse of hypersaline brines, e.g., produced water from the oil and gas industry, waste streams of minimum/zero liquid discharge operations, inland desalination concentrate, landfill leachate, flue gas desulfurization wastewater, treatment of high-scaling propensity feedwaters, and the like.

[0072] Although the invention has been described and illustrated with respect to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without parting from the spirit and scope of the present invention.