Systems and methods for producing renewable hydrogen

Abstract

Methods for producing renewable hydrogen and systems related to the same are provided.

Description

[0001] SYSTEMS AND METHODS FOR PRODUCING RENEWABLE HYDROGEN

[0002] BACKGROUND

[0003] Technical Field

[0004] The present disclosure generally relates to methods for producing renewable hydrogen and systems related to the same.

[0005] Description of the Related Art

[0006] Currently, hydrogen is mainly used as an industrial feedstock, primarily for the production of ammonia and methanol, and in petroleum refining. Most hydrogen currently comes from fossil sources, primarily natural gas.

[0007] However, a “hydrogen economy” is developing that aims to use hydrogen to decarbonize economic sectors which are hard to electrify, such as in the production of fuels (z.e., “e-fuels”) for long-haul transport. Additionally, there is a desire to replace the hydrogen used in the production of ammonia and methanol with sustainably-produced hydrogen (z.e., to produce “green ammonia”). These new and expanded uses of hydrogen would significantly drive-up demand many -fold from current production level. Hydrogen can be produced by electrolysis of water using renewable power sources such as wind and solar (rather than from natural gas).

[0008] However, current technology for electrolysis of water to produce hydrogen is not well suited for truly world-scale deployment, as would be needed to offset significant greenhouse gas emissions.

[0009] BRIEF SUMMARY

[0010] The inventors of the present disclosure recognized that there was no known practical solution to the problem of electrolyzers needing very large volumes of very pure water as a feedstock for electrolysis into H2 and O2. Technologies such as reverse osmosis (RO) and deionization (DI) do exist for producing pure water suitable for electrolysis, however, they also produce an effluent stream (z.e., having the salts removed from the pure water). However, there is no practical means for dealing with this effluent stream at large-scale. Current methods involve further concentrating the salts in the effluent stream by evaporating water in large, open evaporative ponds, which reduces the volume of effluent requiring final disposal. However, this is at great cost with respect to an economics and land use perspective. In some other cases these brackish aqueous streams can be disposed into existing bodies of water, such as a river or sea but the permits required for such disposal is extremely onerous and not always available.

[0011] Counter-intuitively, electrolysis is an endothermic reaction, but generates a significant amount of heat (z.e., as a result of inefficiencies). For instance, an electrolyzer that has a thermodynamic efficiency of about 60% will convert about 40% of the input electricity into heat, which must be removed from the system.

[0012] Synergistically, the present disclosure provides an elegant solution to both the problem of heat removal and accumulation of the effluent. Briefly, the treatment of the effluent stream is coupled with the need to generate cooling water for the system.

[0013] In an aspect, provided herein is a method for cooling a process that includes an electrolyzer. The method can include separating an aqueous feedstock into a purified water stream and a residual aqueous stream, where the residual aqueous stream contains dissolved solids that were present in the aqueous feedstock; adding the residual aqueous stream to an aqueous brine; electrolyzing the purified water stream to produce H2, O2, and heat; cooling the electrolyzer using a cooling fluid; transferring heat from the cooling fluid to the aqueous brine; evaporating water from the aqueous brine, thereby cooling the aqueous brine and concentrating salts in the aqueous brine; and purging a portion of the aqueous brine.

[0014] In some embodiments, the purified water stream has a resistivity of at least about 1 megaohm-centimeters (MQ-cm).

[0015] In some embodiments, the purified water stream has a resistivity of at least about 15 mega-ohm-centimeters (MQ-cm).

[0016] In some embodiments, the purified water stream has less than about 0.5 parts-per-million (ppm) total dissolved solids (TDS).

[0017] In some embodiments, the purified water stream has less than about 0.05 parts-per- million (ppm) total dissolved solids (TDS).

[0018] In some embodiments, dissolved solids include salts.

[0019] In some embodiments, the salts include Ca, Mg, or Na cations.

[0020] In some embodiments, the salts include Cl, CO3, or NO3 anions.

[0021] In some embodiments, the aqueous feedstock is separated using a reverse osmosis (RO) module, a deionization (DI) module, or a combination thereof.

[0022] In some embodiments, the purified water stream is electrolyzed using a proton exchange membrane (PEM) electrolyzer, an alkaline electrolyzer, an Anion Exchange Membrane (AEM) electrolyzer, a Solid Oxide State (SOS) electrolyzer, or a combination thereof. In some embodiments, electrical power for the electrolyzer is generated from a renewable resource.

[0023] In some embodiments, at least about 20% of the electrical power is converted into heat.

[0024] In some embodiments, the cooling fluid is water.

[0025] In some embodiments, the cooling fluid is supplemented with a portion of the purified water stream.

[0026] In some embodiments, the electrolyzer is cooled with the aid of a heat exchanger.

[0027] In some embodiments, heat is transferred from the cooling fluid to the aqueous brine with the aid of a heat exchanger.

[0028] In some embodiments, water is evaporated from the aqueous brine with the aid of an evaporative cooling tower.

[0029] In some embodiments, a flow rate of the aqueous brine that is purged is less than about 10% of a flowrate of the residual aqueous stream that is generated.

[0030] In some embodiments, the method further comprises converting the H2 into ammonia.

[0031] In some embodiments, the method further comprises utilizing the purged aqueous brine in a process that produces aqua-ammonia or urea ammonium nitrate (UAN).

[0032] In some embodiments, a pressure of the cooling fluid is higher than a pressure of the aqueous brine when heat is transferred from the cooling fluid to the aqueous brine.

[0033] In some embodiments, portions of equipment that are in contact with the aqueous brine are made from salt-tolerant materials.

[0034] In some embodiments, the purged aqueous brine is further evaporated in an evaporative pond.

[0035] In another aspect, provided herein is a system for cooling an electrolyzer, the system comprising: a water purifier configured to separate an aqueous feedstock into a purified water stream and a residual aqueous stream, wherein the residual aqueous stream contains dissolved solids that were present in the aqueous feedstock and is fed into an aqueous brine; an electrolyzer configured to electrolyze the purified water stream to produce H2, O2, and heat, which heat is capable of being transferred to a cooling fluid; a heat exchanger configured to transfer the heat from the cooling fluid to the aqueous brine; and an evaporator configured to evaporate water from the aqueous brine, thereby cooling the aqueous brine and concentrating the dissolved solids in the aqueous brine.

[0036] In some embodiments, the system further comprises a purge configured to purge a portion of the aqueous brine. In some embodiments, the water purifier comprises a reverse osmosis (RO) module, a deionization (DI) module, or a combination thereof.

[0037] In some embodiments, the electrolyzer is a proton exchange membrane (PEM) electrolyzer, an alkaline electrolyzer, an Anion Exchange Membrane (AEM) electrolyzer, a Solid Oxide State (SOS) electrolyzer, or a combination thereof.

[0038] In some embodiments, the cooling fluid is supplemented with a portion of the purified water stream.

[0039] In some embodiments, the electrolyzer is cooled with the aid of a heat exchanger.

[0040] In some embodiments, the evaporator is an evaporative cooling tower.

[0041] In some embodiments, a flow rate of the aqueous brine that is purged is less than about 10% of a flowrate of the residual aqueous stream that is generated.

[0042] In some embodiments, the system further comprises a module for converting the H2 into ammonia.

[0043] In some embodiments, the system further comprises a module capable of utilizing the purged aqueous brine in a process that produces aqua-ammonia or urea ammonium nitrate (UAN).

[0044] In some embodiments, a pressure of the cooling fluid is higher than a pressure of the aqueous brine when heat is transferred from the cooling fluid to the aqueous brine.

[0045] In some embodiments, portions of the heat exchanger or the evaporator that are in contact with the aqueous brine are made from salt-tolerant materials.

[0046] In some embodiments, the system further comprises an evaporative pond that is capable of further evaporating water from purged aqueous brine.

[0047] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of subject matter within this disclosure are contemplated as being part of the inventive subject matter disclosed herein.

[0048] Still other aspects, examples, and advantages of these exemplary aspects and examples, are discussed in detail below. Moreover, it is to be understood that both the foregoing information and the following detailed description are merely illustrative examples of various aspects and examples, and are intended to provide an overview or framework for understanding the nature and character of the claimed aspects and examples. Any example disclosed herein may be combined with any other example in any manner consistent with at least one of the objects, aims, and needs disclosed herein, and references to “an example,” “some examples,” “an alternate example,” “various examples,” “one example,” “at least one example,” “ this and other examples” or the like are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described in connection with the example may be included in at least one example. The appearances of such terms herein are not necessarily all referring to the same example.

[0049] BRIEF DESCRIPTION OF THE FIGURES

[0050] FIG. 1 shows an example of the systems and methods described herein.

[0051] DETAILED DESCRIPTION

[0052] Water treatment is a significant unmet need for electrolyzer-based processes.

[0053] Electrolyzers need very pure water as a feed stream. For example, alkaline electrolyzers typically require water with resistivity above 1 mega-ohm-centimeter (MQ*cm) and proton exchange membrane (PEM) electrolyzers use ultra-pure water with resistivity above 15 MQ-cm. In terms of total dissolved solids (TDS) (z.e., mainly salts), this equates to less than about 0.5 parts per million (ppm) for alkaline electrolyzers and less than about 0.05 ppm for PEM units. For reference, 100% ultrapure water (z.e., ~0 ppm TDS), typically used for microelectronics, has a resistivity above 18 MQ-cm at 25 C. Distilled water is in the 10-18 MQ-cm range.

[0054] The raw water, whether it is water treated by a municipality, drawn from a freshwater source, well-water, or sea water, usually undergoes a series of pre-treatments that can include filtration, sedimentation, and / or nanofiltration prior to being fed to the water purifier for bulk mineral removal and dissolved salts.

[0055] Typically, both alkaline and PEM units can adopt a combination of RO and DI to produce their feed water. Conventional reverse osmosis (RO) systems (e.g., for desalination) generate water with a resistivity above 1 MQ-cm. Deionization (DI) systems generate water with a very wide range of purity e.g., 0.05-18 MQ-cm) depending on the specific DI system used and the quality of the raw water source.

[0056] There are significant problems associated with the water treatment as described above for electrolyzer-based processes, including electro-fuels, green ammonia, or methanol. For example, the extensive treatment required to generate a feed stream with the necessary water quality for use in an electrolyzer produces one or more effluent streams (i.e., residual aqueous stream) that contain (i) most of the undesired compounds originally present in the raw water stream and (ii) traces of any chemicals used in the water treatment itself (e.g., chlorine).

[0057] The water treatment units that generate most of the water effluent streams are RO and DI. The RO unit, depending on the quality of the water source and its specific design, can generate an effluent that has about 15-50% of the initial raw water stream and contains most of the dissolved salts originally present in the feed stream (z.e., aqueous feedstock). For example, if the aqueous feedstock has 100 ppm TDS, the RO can generate an effluent (the RO reject stream) with about 20-25% of the feed flow and a TDS of approximately 400-500 ppm.

[0058] In a 2-vessel DI module, the cations (e.g., Ca2+, Mg2+, Na+, etc.) are exchanged with hydrogen ions (H+) via contact with a strong acid resin. Then, the anions (e.g., as COs2’, Cl’, NO3’, etc.) are exchanged with hydroxyl ions (OH’) via contact with a strong base resin. Once the resins are saturated with the anions and cations present in the feed water, they can be regenerated with a strong acid (e.g., HC1 or H2SO4) and a strong base (e.g., NaOH). As a result of the ion exchange process, the water effluent from the regeneration step contains the anions and cations originally present in the aqueous feedstock combined with the anions from the strong acid (e.g., Cl’ or SO42’) and the cations from the strong base (e.g., Na+). The DI regeneration effluent can be similar to the RO reject stream, / .e., the residual aqueous stream (effluent) contains the TDS originally present on the aqueous feedstock at a significantly higher concentration.

[0059] The disposal of these water effluent streams, whether they are combined together or kept separated, presents several technical, environmental and economic challenges, which all stem from the fact that there is no effective treatment to convert minerals and salts into an easily disposable stream.

[0060] There are two conventional solutions employed to dispose of water effluents with higher than acceptable salinity. First, if a body of water with sufficient flow and volume to dilute the effluent is available, the effluent is simply disposed into such body of water (e.g., a river or the sea). Such a disposal needs to take place in a manner such that the effluent does not alter the quality of the ecosystem of the receiving body of water. For example, this is achieved via ensuring that the flow of the effluent is extremely smaller when compared to flow and volume of the receiving body, distributing the effluent into the receiving body via large structures that prevent any alteration of the local parameters at the point of effluent injection, and other design and operating practices well established within environmental engineering. If such a body of water is not available, effluents with high mineral content are usually disposed into evaporative ponds. These generally comprise a series of basins, made of earth berms and properly lined with multiple layers of membranes to prevent ground percolation, where water is evaporated to the atmosphere and salt accumulated to the bottom. Usually, the last evaporative ponds in the series receive brines with a very high salinity and operate in parallel, so they can be emptied on a regular swing basis once the water is fully evaporated and the solids are deposited to the bottom. The solids removed from these ponds can be disposed to landfills or other appropriate destinations.

[0061] However, both evaporative ponds and disposal into bodies of water as described above present several challenges given the large volumes of water with relatively small amounts of minerals contained in them. From a technical perspective, both methods require customengineering of large structures, either civil-mechanical (for proper distribution of the effluent into the disposal body) or civil-hydraulic (for proper handling of the effluent in evaporative ponds and continuous monitoring of the percolation rates). From an environmental perspective, the effluent has the potential to contaminate the external environment, either by affecting the local environment of the receiving body of water or by contaminating the ground and, possibly, any aquifer underneath the evaporative ponds. And from an economic perspective, proper disposal of the water effluent can require the construction and operation of significant infrastructure, which can represent a significant portion of the capital expense of the overall system and increase the overall operating budget.

[0062] Electrolyzers require significant cooling due to their thermodynamic inefficiency. Assuming an average efficiency of about 60%, that means that about 40% of the electrical power that is fed to the electrolyzer needs to be removed from the unit in the form of waste heat. Such cooling can be provided via heat exchange with a cooling fluid (e.g., water). In some instances, this cooling water can be part of a closed water circuit cooled via indirect heat exchange with air (e.g., via an air cooler with natural or forced convection). In other instances, this cooling water can be part of an open water loop cooled due to evaporation via direct contact with air (e.g., in a cooling tower). While evaporative cooling is usually more effective than indirect heat exchange with air, such an open loop requires a continuous make-up of fresh water (which usually needs to be chemically treated to prevent fouling) and a purge, which creates another stream of water that needs to be properly disposed. Furthermore, most electrolyzer-based processes require further cooling (in addition to that needed for the electrolyzer itself), ie., for units downstream of the electrolyzer (e.g., reactor effluents to be cooled prior to separations and purifications). The systems and methods described herein can synergistically cool the electrolyzer (including downstream units, if required) and process the effluent water created in production of the electrolyzer feedstock. In an aspect, provided herein is a method for cooling a process that includes an electrolyzer. The method can include separating an aqueous feedstock into a purified water stream and a residual aqueous stream, where the residual aqueous stream contains dissolved solids that were present in the aqueous feedstock; adding the residual aqueous stream to an aqueous brine; electrolyzing the purified water stream to produce H2, O2, and heat; cooling the electrolyzer using a cooling fluid; transferring heat from the cooling fluid to the aqueous brine; evaporating water from the aqueous brine, thereby cooling the aqueous brine and concentrating salts in the aqueous brine; and purging a portion of the aqueous brine.

[0063] In another aspect, provided herein is a system for cooling an electrolyzer. With reference to FIG. 1, the system can include a water purifier 100 configured to separate an aqueous feedstock 102 into a purified water stream 104 and a residual aqueous stream 106, wherein the residual aqueous stream contains dissolved solids that were present in the aqueous feedstock and is fed into an aqueous brine 108. An electrolyzer 110 can be configured to electrolyze the purified water stream 104 to produce hydrogen (H2) 112, oxygen (O2) 114, and heat, which heat is capable of being transferred to a cooling fluid 116. The system can further include a heat exchanger 118 configured to transfer the heat from the cooling fluid 116 to the aqueous brine 108. An evaporator 120 can be configured to evaporate water 122 from the aqueous brine, thereby cooling the aqueous brine and concentrating the dissolved solids in the aqueous brine. A pump 124 can recirculate the cooled aqueous brine 108 to the heat exchanger 118. A portion of the aqueous brine can be purged 126 from the system (e.g., and disposed of or used in a subsequent process). If the residual aqueous stream has inadequate volume to provide the cooling needs, additional make-up water 128 can be added to the brine. Furthermore, the cooling fluid can be supplemented with 130 some of the purified water stream.

[0064] In the systems and methods described herein, the disposal of the water treatment reject stream is combined with the need to generate cooling water. The water effluent from the electrolyzer water treatment train can be used as the make-up stream for an evaporative open circuit. If not sufficient, the effluent stream can be supplemented with additional water (likely coming from the same original source that is used to feed the electrolyzer).

[0065] Once mixed with the cooling water coming from the evaporative device (for example, a cooling tower), the mixed stream can be sent to a heat exchanger, such as a plate & frame exchanger. In the exchanger, the cooling water cools another stream of water (or other appropriate cooling fluid) that is part of a closed loop cooling system.

[0066] The warm cooling water exiting the exchanger can be sent to the evaporative device (e.g., a cooling tower), where it is cooled down to the temperature corresponding to the dew point of the atmospheric air. Within the evaporative device a fraction of the cooling water is evaporated to the atmosphere to provide the cooling effect.

[0067] Prior to being mixed again with the make-up stream, a small fraction of the cooling water from the evaporative device can be discharged from the open loop to prevent excessive accumulation of any material originally present in the make-up stream (mostly minerals). The net effect of the systems and methods described herein is that the water effluent from the overall system is considerably reduced in flow at the expense of a vastly increased salinity in the final effluent (the purge stream from the open loop).

[0068] The open loop cooling water system (evaporative devices, pumps, heat exchangers, piping and instrumentation) can be designed in such a way that it can handle a high salinity content in the circulating cooling water. This is akin to what is current done with evaporative cooling water systems fed with seawater (these are popular in Middle East, for example).

[0069] The open loop evaporative system can be operated at a lower pressure than the closed loop cooling system to prevent any possible leaking of water with increased salinity into the closed loop system (which is not designed to handle water with high salinity).

[0070] Process controls and monitoring can be put in place to maintain the salinity of the open loop at the desired levels, e.g., via management of the ratio between make-up and purge streams. Monitoring can also ensure the operation of the closed loop system without any leaking (e.g., using conductivity measurements).

[0071] In some instances, the purge stream from the evaporative system, optionally combined with a fraction of the original water treatment effluent or another water source, can be re-utilized to generate certain aqueous products where some mineral content can be tolerated (for example, aqueous fertilizers). In an electrolyzer-based ammonia process, the water effluent can be used to generate aqua-ammonia products sold as fertilizers. In an electrolyzer-based ammonia process with a downstream urea, ammonium nitrate or Urea-Ammonium Nitrate (UAN) units, the water effluent can be used to generate aqueous solutions of these products.

[0072] The systems and methods described herein can have several technical benefits. For example, it can (greatly) reduce effluent quantity from the overall system. Controllability of the effluent flow at any given time during operation can be achieved via control of the make-up / purge flow ratio. The diminished effluent volume (with higher salinity) can be more easily disposed by being transported offsite to a proper disposal facility and / or by accumulating it in local evaporative ponds (considerably smaller than the ones that would be required without the system described here).

[0073] Any salt accumulation in the open cooling system will occur inside the evaporative device, which can be designed for proper maintenance on a regular basis (e.g., replacement of the packing once salt accumulation reaches a certain level). Any negative effect of salinity on the system (if not handled via proper construction material selection) is confined to the evaporative open loop, which can be properly maintained. If the effluent is re-utilized for product generation, the overall effluent quantity can be minimized or even eliminated.

[0074] The systems and methods described herein can have several environmental benefits. For example, water effluents from the overall system can be minimized or even eliminated.

[0075] Water consumption by the electrolyzer-based process can be minimized (because effluent is re-used as cooling water make-up, which reduces need for fresh water input for that service). If present, effluent flow can be minimized to the point where it is handled in tanks and / or small ponds, thus eliminating risk of environmental contamination. Finally, the operating parameters of the cooling system can be optimized seasonally to provide maximum evaporation (and minimum effluent) when most convenient.

[0076] The systems and methods described herein can have several economic benefits. Capital expense can be reduced by reducing infrastructure needed for water disposal (e.g., fewer evaporative ponds or effluent distributors). Operating expense can be reduced by easier disposal of the effluent streams (liquid and solid).

[0077] The above-described embodiments can be implemented in any of numerous ways. For example, the embodiments may be implemented using hardware, software or a combination thereof. When implemented in software, the software code can be executed on any suitable processor or collection of processors, whether provided in a single computer or distributed among multiple computers. It should be appreciated that any component or collection of components that perform the functions described above can be generically considered as one or more controllers that control the above-discussed functions. The one or more controllers can be implemented in numerous ways, such as with dedicated hardware or with one or more processors programmed using microcode or software to perform the functions recited above.

[0078] In this respect, it should be appreciated that one implementation of the embodiments of the present invention comprises at least one non-transitory computer-readable storage medium (e.g., a computer memory, a portable memory, a compact disk, etc.) encoded with a computer program (z.e., a plurality of instructions), which, when executed on a processor, performs the above-discussed functions of the embodiments of the present invention. The computer-readable storage medium can be transportable such that the program stored thereon can be loaded onto any computer resource to implement the aspects of the present invention discussed herein. In addition, it should be appreciated that the reference to a computer program which, when executed, performs the above-discussed functions, is not limited to an application program running on a host computer. Rather, the term computer program is used herein in a generic sense to reference any type of computer code e.g., software or microcode) that can be employed to program a processor to implement the above-discussed aspects of the present invention.

[0079] Various aspects of the present invention may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing and are therefore not limited in their application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments.

[0080] Also, embodiments of the invention may be implemented as one or more methods, of which an example has been provided. The acts performed as part of the method(s) may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0081] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed. Such terms are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term).

[0082] The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” “having,” “containing”, “involving”, and variations thereof, is meant to encompass the items listed thereafter and additional items.

[0083] The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and / or listed in the Application Data Sheet, including U.S. Provisional Patent Application No. 63 / 508,231, filed on June 14, 2023, to which this application claims priority, are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments.

[0084] Having described several embodiments of the invention in detail, various modifications and improvements will readily occur to those skilled in the art. Such modifications and improvements are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only, and is not intended as limiting. The invention is limited only as defined by the following claims and the equivalents thereto.

Claims

CLAIMSWhat is claimed is:

1. A method for cooling a process that includes an electrolyzer, the method comprising: a. separating an aqueous feedstock into a purified water stream and a residual aqueous stream, wherein the residual aqueous stream contains dissolved solids that were present in the aqueous feedstock; b. adding the residual aqueous stream to an aqueous brine; c. electrolyzing the purified water stream to produce H2, O2, and heat; d. cooling the electrolyzer using a cooling fluid; e. transferring heat from the cooling fluid to the aqueous brine; f. evaporating water from the aqueous brine, thereby cooling the aqueous brine and concentrating salts in the aqueous brine; and g. purging a portion of the aqueous brine.

2. The method of Claim 1, wherein the purified water stream has a resistivity of at least about 1 mega-ohm-centimeters (MQ-cm).

3. The method of Claim 1, wherein the purified water stream has a resistivity of at least about 15 mega-ohm-centimeters (MQ-cm).

4. The method of Claim 1, wherein the purified water stream has less than about 0.5 parts-per-million (ppm) total dissolved solids (TDS).

5. The method of Claim 1, wherein the purified water stream has less than about 0.05 parts-per-million (ppm) total dissolved solids (TDS).

6. The method of Claim 1, wherein dissolved solids include salts.

7. The method of Claim 6, wherein the salts include Ca, Mg, or Na cations.

8. The method of Claim 6, wherein the salts include Cl, CO3, or NO3 anions.

9. The method of Claim 1, wherein the aqueous feedstock is separated using a reverse osmosis (RO) module, a deionization (DI) module, or a combination thereof.

10. The method of Claim 1, wherein the purified water stream is electrolyzed using a proton exchange membrane (PEM) electrolyzer, an anion exchange membrane (AEM) electrolyzer, a solid oxide state (SOS) electrolyzer, an alkaline electrolyzer, or a combination thereof.

11. The method of Claim 1, wherein electrical power for the electrolyzer is generated from a renewable resource.

12. The method of Claim 11, wherein at least about 20% of the electrical power is converted into heat.

13. The method of Claim 1, wherein the cooling fluid is water.

14. The method of Claim 1, wherein the cooling fluid is supplemented with a portion of the purified water stream.

15. The method of Claim 1, wherein the electrolyzer is cooled with the aid of a heat exchanger.

16. The method of Claim 1, wherein heat is transferred from the cooling fluid to the aqueous brine with the aid of a heat exchanger.

17. The method of Claim 1, wherein water is evaporated from the aqueous brine with the aid of an evaporative cooling tower.

18. The method of Claim 1, wherein a flow rate of the aqueous brine that is purged is less than about 10% of a flowrate of the residual aqueous stream that is generated.

19. The method of Claim 1, further comprising converting the H2 into ammonia.

20. The method of Claim 1, further comprising utilizing the purged aqueous brine in a process that produces aqua-ammonia or urea ammonium nitrate (UAN).

21. The method of Claim 1, wherein a pressure of the cooling fluid is higher than a pressure of the aqueous brine when heat is transferred from the cooling fluid to the aqueous brine.

22. The method of Claim 1, wherein portions of equipment that are in contact with the aqueous brine are made from salt-tolerant materials.

23. The method of Claim 1, wherein the purged aqueous brine is further evaporated in an evaporative pond.

24. A system for cooling an electrolyzer, the system comprising: a. a water purifier configured to separate an aqueous feedstock into a purified water stream and a residual aqueous stream, wherein the residual aqueous stream contains dissolved solids that were present in the aqueous feedstock and is fed into an aqueous brine; b. an electrolyzer configured to electrolyze the purified water stream to produce H2, O2, and heat, which heat is capable of being transferred to a cooling fluid; c. a heat exchanger configured to transfer the heat from the cooling fluid to the aqueous brine; and d. an evaporator configured to evaporate water from the aqueous brine, thereby cooling the aqueous brine and concentrating the dissolved solids in the aqueous brine.

25. The system of Claim 1, further comprising a purge configured to purge a portion of the aqueous brine.

26. The system of Claim 24, wherein the water purifier comprises a reverse osmosis (RO) module, a deionization (DI) module, or a combination thereof.

27. The method of Claim 24, wherein the electrolyzer is a proton exchange membrane (PEM) electrolyzer, an anion exchange membrane (AEM) electrolyzer, a solid oxide state (SOS) electrolyzer, an alkaline electrolyzer, or a combination thereof.

28. The system of Claim 24, wherein the cooling fluid is supplemented with a portion of the purified water stream.

29. The system of Claim 24, wherein the electrolyzer is cooled with the aid of a heat exchanger.

30. The system of Claim 24, wherein the evaporator is an evaporative cooling tower.

31. The system of Claim 25, wherein a flow rate of the aqueous brine that is purged is less than about 10% of a flowrate of the residual aqueous stream that is generated.

32. The system of Claim 24, further comprising a module for converting the Eb into ammonia.

33. The system of Claim 25, further comprising a module capable of utilizing the purged aqueous brine in a process that produces aqua-ammonia or urea ammonium nitrate (UAN).

34. The system of Claim 25, wherein a pressure of the cooling fluid is higher than a pressure of the aqueous brine when heat is transferred from the cooling fluid to the aqueous brine.

35. The system of Claim 24, wherein portions of the heat exchanger or the evaporator that are in contact with the aqueous brine are made from salt-tolerant materials.

36. The system of Claim 24, further comprising an evaporative pond that is capable of further evaporating water from purged aqueous brine.

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