Brine electrolysis system for producing pressurized chlorine and hydrogen gases
11118273 · 2021-09-14
Assignee
Inventors
Cpc classification
C25B9/23
CHEMISTRY; METALLURGY
C25B15/08
CHEMISTRY; METALLURGY
C25B9/13
CHEMISTRY; METALLURGY
International classification
C25B9/23
CHEMISTRY; METALLURGY
C25B15/08
CHEMISTRY; METALLURGY
Abstract
A brine electrolysis system for producing pressurized chlorine and hydrogen gases. In its basic configuration, the brine electrolysis system may comprise: two liquid storage tanks for storing two liquid reactants; a tank having two interior spaces separated by a diaphragm for receiving the liquid reactants; two pumps for regulating the flow of the liquid reactants from the liquid storage tanks to the interior spaces of the tank, two open-bottom cylinders for storing and dispensing two gases; an electrolysis stack assembly for converting the liquid reactants into two gases; and two submersible pumps for pumping each liquid reactant into an electrolysis stack assembly. Each open-bottom cylinder may comprise a float sensor for determining the amount of fluid entering its cylindrical space. The system may further comprise controllers for regulating ionic concentrations within the two interior spaces. Dispense lines and valves may be utilized to release the gases.
Claims
1. A brine electrolysis system, comprising: a tank having first and second interior spaces separated by a diaphragm for storing first and second liquid reactants respectively; first and second pumps in fluid communication with said first and second interior spaces, respectively; first and second open-bottom cylinder disposed within said tank and having first and second cylindrical spaces, respectively; first and second dispense lines disposed outside said tank and in fluid communication with said first and second cylindrical spaces, respectively; first and second submersible pumps disposed within said first and second interior spaces, respectively, and configured to pump first and second liquid reactants; and an electrolysis stack assembly traversing across said first and second interior spaces of said tank and sealably through said diaphragm.
2. The brine electrolysis system recited in claim 1, characterized in that said electrolysis stack assembly comprises: one or more electrolysis stacks for creating first and second gases based on said first and second liquid reactants, respectively; first and second inlets in fluid communication with said first and second submersible pumps, respectively; a first outlet supply line traversing into said first cylindrical space through a first bottom opening of said first open-bottom cylinder for releasing said first gas into said first cylindrical space; and a second outlet supply line traversing into said second cylindrical space through a second bottom opening of said second open-bottom cylinder for releasing said second gas into said second cylindrical space.
3. The brine electrolysis system recited in claim 2, characterized in that said first and second liquid reactants are respectively a sodium chloride and a water; and wherein said first and second gases are a chlorine gas and a hydrogen gas, respectively.
4. The brine electrolysis system recited in claim 1, characterized in that said electrolysis stack assembly is a chlor-alkali electrolysis stack assembly.
5. The brine electrolysis system recited in claim 2, wherein said diaphragm is constructed of an ion-selective membrane configured to permit a counterion (Na+) to flow across said diaphragm from said first interior space to said second interior space.
6. The brine electrolysis system recited in claim 2, further comprising first and second liquid storage tanks in fluid communication with first and second inlets of said first and second pumps, respectively; and first and second motors operably coupled to said first and second pumps, respectively.
7. The brine electrolysis system recited in claim 6, further comprising a brine process controller and an ionic conductivity meter; wherein said ionic conductivity meter is configured to measure a sodium chloride concentration within said first interior space of said tank; and wherein said brine process controller is operably coupled to said first motor and said ionic conductivity meter and regulates said sodium chloride concentration within said first interior space based on said sodium chloride concentration measurements.
8. The brine electrolysis system recited in claim 6, further comprising an alkali process controller and a pH meter; wherein said pH meter is configured to measure a sodium hydroxide concentration within said second interior space of said tank; and wherein said alkali process controller is operably coupled to said second motor and said pH meter and regulates said sodium hydroxide concentration within said second interior space based on said sodium hydroxide concentration measurements.
9. A brine electrolysis system, comprising: a tank having first and second interior spaces separated by a diaphragm; first and second pumps in fluid communication with said first and second interior spaces of said tank, respectively; a first open-bottom cylinder disposed within said first interior space and comprising: a first cylindrical body having a first cylindrical space in fluid communication with said first interior space of said tank; and a first float sensor adapted to raise and lower via buoyancy; a second open-bottom cylinder disposed within said second interior space and comprising: a second cylindrical body having a second cylindrical space in fluid communication with said second interior space of said tank; and a second float sensor adapted to raise and lower via buoyancy; first and second dispense lines disposed outside said tank and respectively coupled to said first and second open-bottom cylinders, such that said first and second dispense lines are in fluid communication with said first and second cylindrical spaces, respectively; first and second submersible pumps disposed within said first and second interior spaces, respectively, and respectively configured to pump a sodium chloride and a water; and a chlor-alkali electrolysis stack assembly traversing across said first and second interior spaces of said tank and sealably through said diaphragm.
10. The brine electrolysis system recited in claim 9, characterized in that said chlor-alkali electrolysis stack assembly comprises: one or more chlor-alkali electrolysis stacks for creating a chlorine gas and a hydrogen gas based on said sodium chloride and said water, respectively; first and second inlets in fluid communication with said first and second submersible pumps, respectively; a first outlet supply line traversing into said first cylindrical space through a first bottom opening of said first open-bottom cylinder for releasing said chlorine gas into said first cylindrical space; and a second outlet supply line traversing into said second cylindrical space through a second bottom opening of said second open-bottom cylinder for releasing said hydrogen gas into said second cylindrical space.
11. The brine electrolysis system recited in claim 9, further comprising first and second liquid storage tanks in fluid communication with first and second inlets of said first and second pumps, respectively, wherein said first and second liquid storage tanks store said sodium chloride and said water, respectively; and first and second motors operably coupled to said first and second pumps, respectively.
12. The brine electrolysis system recited in claim 11, further comprising a brine process controller and an ionic conductivity meter; wherein said ionic conductivity meter is configured to measure a sodium chloride concentration within said first interior space of said tank; and wherein said brine process controller comprises a first variable frequency drive (VFD) operably coupled to said first motor for regulating said sodium chloride concentration within said first interior space based on said sodium chloride concentration measurements.
13. The brine electrolysis system recited in claim 11, further comprising an alkali process controller and a pH meter; wherein said pH meter is configured to measure a sodium hydroxide concentration within said second interior space of said tank; and wherein said alkali process controller comprises a second VFD operably coupled to said second motor for regulating said sodium hydroxide concentration within said second interior space based on said sodium hydroxide concentration measurements.
14. The brine electrolysis system recited in claim 9, wherein said diaphragm is constructed of an ion-selective membrane configured to permit a counterion (Na+) to flow across said diaphragm from said first interior space to said second interior space.
15. A brine electrolysis system, comprising: a tank having first and second interior spaces separated by a diaphragm; a first rotary screw pump having a first outlet that is sealably coupled to a first opening of said tank and in fluid communication with said first interior space; a second rotary screw pump having a second outlet that is sealably coupled to a second opening of said tank and in fluid communication with said second interior space; a first open-bottom cylinder disposed within said first interior space and comprising: a first cylindrical body having a first cylindrical space in fluid communication with said first interior space of said tank; and a first float sensor adapted to raise and lower via buoyancy; a second open-bottom cylinder disposed within said second interior space and comprising: a second cylindrical body having a second cylindrical space in fluid communication with said second interior space of said tank; and a second float sensor adapted to raise and lower via buoyancy; a first dispense line disposed outside said tank and sealably coupled to said first open-bottom cylinder, such that said first dispense line is in fluid communication with said first cylindrical space; a second dispense line disposed outside said tank and sealably coupled to said second open-bottom cylinder, such that said second dispense line is in fluid communication with said second cylindrical space; a first submersible pump disposed within said first interior space for pumping a sodium chloride; a second submersible pump disposed within said second interior space for pumping a water; and a chlor-alkali electrolysis stack assembly traversing across said first and second interior spaces of said tank and sealably through said diaphragm, said chlor-alkali electrolysis stack assembly, comprising: one or more chlor-alkali electrolysis stacks for creating a chlorine gas and a hydrogen gas based on said sodium chloride and said water, respectively; first and second inlets in fluid communication with said first and second submersible pumps, respectively; a first outlet supply line traversing into said first cylindrical space through a first bottom opening of said first open-bottom cylinder for releasing said chlorine gas into said first cylindrical space; and a second outlet supply line traversing into said second cylindrical space through a second bottom opening of said second open-bottom cylinder for releasing said hydrogen gas into said second cylindrical space.
16. The brine electrolysis system recited in claim 15, further comprising first and second liquid storage tanks in fluid communication with first and second inlets of said first and second rotary screw pumps, respectively; and wherein said first and second liquid storage tanks respectively store said sodium chloride and said water.
17. The brine electrolysis system recited in claim 16, further comprising first and second motors operably coupled to said first and second rotary screw pumps, respectively.
18. The brine electrolysis system recited in claim 17, further comprising a brine process controller and an ionic conductivity meter; wherein said ionic conductivity meter is configured to measure a sodium chloride concentration within said first interior space of said tank; and wherein said brine process controller comprises a first VFD operably coupled to said first motor for regulating said sodium chloride concentration within said first interior space based on said sodium chloride concentration measurements.
19. The brine electrolysis system recited in claim 18, further comprising an alkali process controller and a pH meter; wherein said pH meter is configured to measure a sodium hydroxide concentration within said second interior space of said tank; and wherein said alkali process controller comprises a second VFD operably coupled to said second motor for regulating said sodium hydroxide concentration within said second interior space based on said sodium hydroxide concentration measurements.
20. The brine electrolysis system recited in claim 15, wherein said diaphragm is constructed of an ion-selective membrane configured to permit a counterion (Na+) to flow across said diaphragm from said first interior space to said second interior space.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The drawings are illustrative embodiments. They do not illustrate all embodiments. They do not set forth all embodiments. Other embodiments may be used in addition or instead. Details, which may be apparent or unnecessary, may be omitted to save space or for more effective illustration. Some embodiments may be practiced with additional components or steps and/or without all of the components or steps, which are illustrated. When the same numeral appears in different drawings, it is intended to refer to the same or like components or steps.
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(10) It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not to be viewed as being restrictive of the embodiments, as claimed. Further advantages of these embodiments will be apparent after a review of the following detailed description of the disclosed embodiments, which are illustrated schematically in the accompanying drawings and in the appended claims.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
(11) In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of various aspects of one or more embodiments of the brine electrolysis system for producing pressurized chlorine and hydrogen gases. However, these embodiments may be practiced without some or all of these specific details. In other instances, well-known methods, procedures, and/or components have not been described in detail so as not to unnecessarily obscure the aspects of these embodiments.
(12) Before the embodiments are disclosed and described, it is to be understood that these embodiments are not limited to the particular structures, process steps, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that the terminology used herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.
(13) Reference throughout this specification to “one embodiment,” “an embodiment,” or “another embodiment” may refer to a particular feature, structure, or characteristic described in connection with the embodiments of the present disclosure. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification may not necessarily refer to the same embodiment.
(14) Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in various embodiments. In the following description, numerous specific details are provided, such as examples of materials, fasteners, sizes, lengths, widths, shapes, etc . . . , to provide a thorough understanding of the embodiments. One skilled in the relevant art will recognize, however, that the scope of the disclosed embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, etc. . . . . In other instances, well-known structures, materials, or operations are generally not shown or described in detail to avoid obscuring aspects of the disclosure.
DEFINITIONS
(15) In the following description, certain terminology is used to describe certain features of the embodiments of the brine electrolysis system in accordance with the present disclosure. For example, as used herein, unless otherwise specified, the term “substantially” refers to the complete, or nearly complete, extent or degree of an action, characteristic, property, state, structure, item, or result. As an arbitrary example, an object that is “substantially” surrounded would mean that the object is either completely surrounded or nearly completely surrounded. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking, the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained.
(16) The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. As another arbitrary example, a composition that is “substantially free of” particles would either completely lack particles, or so nearly completely lack particles that the effect would be the same as if it completely lacked particles. In other words, a composition that is “substantially free of” an ingredient or element may still actually contain such item as long as there is no measurable effect thereof.
(17) As used herein, the term “liquid reactant” generally refers to a liquid substance capable of entering and being altered in the course of a chemical reaction, including without limitation, a first liquid reactant and a second liquid reactant. The term “first liquid reactant” generally refers to sodium chloride or brine, including varying concentrations of sodium chloride, but may also include varying concentration of potassium chloride, or mixture of sodium hydroxide and potassium hydroxide. The term “second liquid reactant” generally refers to water, including water having varying concentrations of sodium hydroxide, but may also include varying concentrations of potassium hydroxide, or mixture of sodium hydroxide and potassium hydroxide thereof. The substitution of sodium and potassium in brine being well known.
(18) As used herein, the term “approximately” may refer to a range of values of 100% of a specific value. For example, the expression “approximately 150 inches” may comprise the values of 150 inches 10%, i.e. the values from 135 inches to 165 inches.
(19) As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint. In some cases, the term “about” is to include a range of not more than about two inches of deviation.
(20) As used herein in this disclosure, the singular forms “a” and “the” may include plural referents, unless the context clearly dictates otherwise. Thus, for example, reference to an “opening” can include reference to one or more of such openings.
(21) The present disclosure relates generally to electrolysis systems, and more particularly, to brine electrolysis systems used for the production of pressurized hydrogen and chlorine gases. The brine electrolysis system disclosed herein preferably produces and dispenses hydrogen and chlorine gases at elevated pressure in equilibrium. In particular, liquid reactant streams of concentrated sodium chloride (e.g., brine or aqueous solution of NaCl) and water are preferably circulated through the brine electrolysis system, which generates chlorine gas and hydrogen gas at elevated pressure. Production of hydrogen and chlorine gases at elevated pressure avoids the use of gas compression and simplifies drying of gases downstream as well as pressure management in additional processing. The hydrogen gas may be supplied as fuel for UUVs utilizing fuel cell propulsion. The chlorine gas may be used to react with ethane to produce polyvinyl chloride material fed to a 3-D or additive manufacturing printer.
(22) In its basic configuration, the brine electrolysis system may comprise: two liquid storage tanks for storing two liquid reactants; a tank having two interior spaces separated by a diaphragm for receiving the two liquid reactants; two pumps for regulating the flow of the two liquid reactants from the liquid storage tanks to the two interior spaces of the tank; an electrolysis stack assembly for converting the two liquid reactants into two gases; two submersible pumps for pumping each liquid reactant into the electrolysis stack assembly; and two open-bottom cylinders for storing and dispensing two gases. Each open-bottom cylinder may comprise a float sensor for determining the amount of fluid entering its cylindrical space of each open-bottom cylinder. The system may further comprise one or more controllers for regulating reactant concentrations based upon ionic conductivity measurements in the two interior spaces. Dispense lines and dispense valves may be utilized to release the gases from the tank.
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(24) The tank 150 may be any fluid tight structure having at least two interior spaces 106, 107 (shown in
(25) The tank 150 may also be a hyperbaric tank adapted to withstand high fluid pressure and may comprise one or more openings for coupling or fitting various components. For example, as shown in
(26) In various embodiments, the tank 150 may be constructed of any metal or high durable material such as steel and aluminum but may also be constructed from other suitable materials such as fiberglass or plastic. Alternatively, the tank 150 may be constructed of a composite structure such as carbon fiber wrapped aluminum and polymer liners. In various embodiments, the tank 150 may also comprise a liner to serve as a gas permeation barrier in order to prevent leaking of a fluid, liquid, gas, or other substance. Embodiments of the liners may be constructed of carbon fiber wrapped aluminum, for example.
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(29) In various embodiments, the first and second pumps 120,220 may be a positive displacement pump such as a rotary screw pump, such as the one shown in
(30) Importantly, as mentioned above, the brine electrolysis system 1000 may also comprise an electrolysis stack assembly 310 (shown in
(31) Furthermore,
(32) Finally,
(33) Other embodiments of the brine electrolysis system 1000 may further comprise additional components such as sensors for managing the process flow of fluids, liquids, and gases. For example, additional sensors of the brine electrolysis system 1000 may include gas component fraction sensors to monitor the gas fraction for revealing combustible mixtures. Other additional components may also include pressure relief devices for preventing or relieving pressure.
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(35) Specifically,
(36) The electrolysis stack assembly 310 is preferably a chlor-alkali electrolysis stack assembly configured to dissociate brine and water in order to produce chlorine gas 199 and sodium hydroxide. The electrolysis stack assembly 310 is also preferably configured to dissociate water in order to produce hydrogen gas 299. The electrolysis stack assembly 310 is generally sealably fitted with the diaphragm 320 and may traverse across the first interior space 106 and second interior space 107 through the diaphragm 320. Further, the electrolysis stack assembly 310 is preferably disposed between the open-bottom cylinders 410, 510 and the first and second submersible pumps 190, 290. In this manner, the electrolysis stack assembly 310 may be in fluid communication with the first interior space 106 and second interior space 107 of the tank 150 to perform electrolysis on sodium chloride and water stored in the tank 150.
(37) In order to supply chlorine gas 199 and hydrogen gas 299, additional supply lines (not shown) may be coupled to the first and second dispense lines 170, 270 outside the tank 150 and may be controlled by the dispense valves 171, 271. The first and second submersible pumps 190, 290 preferably circulate the first liquid reactant 140 (e.g., sodium chloride, brine) and second liquid reactant 240 (water, water/sodium hydroxide combination) through the electrolysis stack assembly 310. Specifically, during operation of the brine electrolysis system 1000, the first liquid reactant 140 may be pumped via the first pump 120 from the first liquid storage tank 100, which may store a higher concentration of sodium chloride (i.e., a saturated solution), into the tank 150 at an elevated pressure. Here, on one side of the diaphragm 320, the first submersible pump 190 may transfer the sodium chloride) through the electrolysis stack assembly 310 to produce chlorine gas 199. At the same time, sodium ion Na(+) may transfer across the ion-selective membrane of the diaphragm 320, and as a result, the concentration of the remaining sodium chloride liquid (now preferably entrained with chlorine gas 199) may be lowered upon exiting the electrolysis stack assembly 310. During this time, on the other side of the diaphragm 320, the second liquid reactant 240 (i.e., water) may be pumped via the second pump 220 from the second liquid storage tank 200, which may store a neutral concentration (i.e., pH=7) into the tank 150 at an elevated pressure. The second submersible pump 290 may transfer the water through the electrolysis stack assembly 310 to produce hydrogen gas 299. At the same time, sodium ion Na(+), which transferred across the ion-selective membrane of the diaphragm 320, may increase the concentration of sodium hydroxide within the water (i.e., alkali now preferably entrained with hydrogen gas 299) to create a water/sodium hydroxide liquid combination. Importantly, the sodium chloride concentration of the first liquid reactant 140 may be lowered, and the sodium hydroxide concentration within the water of the second liquid reactant 240 may be raised during circulation of the first and second submersible pumps 190, 290 through the electrolysis stack assembly 310. In this manner, the volume of the liquid reactants (i.e., sodium chloride, water) should be replaced via transfer through the first and second outflow lines 160, 260 and first and second liquid storage tanks 100, 200.
(38) Importantly,
(39) The brine submersible pump flow rate gauge 196 and alkali submersible pump flow rate gauge 296 are preferably instruments configured to measure the volumetric flow rates of the first and second submersible pumps 190, 290 within the first interior space 106 and second interior space 107 of the tank 150. The brine submersible pump flow rate gauge 196 and alkali submersible pump flow rate gauge 296 may also provide feedback to the controller 900 via flow rate lines 197, 297 (shown in
(40) The power supply positive lead flange 830 and power supply negative lead flange 840 are preferably in electrical communication with the end plates of the electrolysis stack assembly 310 and establish an electrical potential difference between the end plates of the electrolysis stack assembly 310 for electrolysis operation. The power supply positive lead flange 830 and power supply negative lead flange 840 are preferably in electrical communication with the power supply 820 via power supply lines 831, 841 (shown in
(41) Finally,
(42) In operation, the first submersible pump 190 circulates first liquid reactant 140 (i.e., sodium chloride) through the electrolysis stack assembly 310 within the tank 150. Additionally, the second submersible pump 290 circulates the second liquid reactant 240 (i.e., water) through the electrolysis stack assembly 310. In various embodiments, application of a DC potential difference between the end plates of the electrolysis stack assembly 310 via the power supply positive lead flange 830 and power supply negative lead flange 840 may then convert the sodium chloride and water via electrolysis to generate sodium chloride with entrained chlorine gas 199 and a water/sodium hydroxide combination with entrained hydrogen gas 299. The sodium chloride with entrained chlorine gas 199 and water with entrained hydrogen gas 299 may be fed through outlet supply lines 135, 235 and into the first and second cylinder spaces 420, 520 (shown in
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(45) By way of example, within the cylinder space 420, 520, gases such as chlorine gas 199 or hydrogen gas 299 may enter via the outlet supply lines 135, 235 and may accumulate within the top portion of the cylinder space 420, 520. From there, the accumulated gas may reposition the float sensors 430, 530 and may escape through the first and second dispense lines 170, 270, upon opening of a corresponding dispense valve 171, 172 of the first and second dispense lines 170, 270. In particular, the first outlet supply line 135 may traverse or extend towards the upper area of the first cylinder space 420, so as to allow gas (e.g., chlorine gas 199) to accumulate initially in the upper area of the first cylinder space 420 and exit the first dispense line 170. Similarly, the second outlet supply line 235 may traverse or extend towards the upper area of the second cylinder space 520, so as to allow gas (e.g., hydrogen gas 299) accumulate initially in the upper area of the second cylinder space 520 and exit the second dispense line 270. In other embodiments, the first outlet supply line 135 and second outlet supply line 235 may extend around the mid-section of the cylinder space 420, 520 to allow gas to exit and accumulate initially in the mid-area of the cylinder space 420, 520. Due to the communication of the liquid reactants at substantially the same pressure between the inner and outer areas of the open-bottom cylinders 410, 510, the open-bottom cylinders 410, 510 need not be constructed of high strength materials, and thus, may be constructed of other suitable materials such as polymers, composites, and the like.
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(47) Finally, embodiments of the first and second pumps 120,220 may be screw-pumps that allow fluid to enter and leave the tank 150. The accumulation or removal of fluid may increase or decrease the volume of the tank 150, thereby affecting the fluid pressure of the tank 150. Thus, because the fluid and gas may interact within the cylinder space 420, 520, pressure equilibrium within the open-bottom cylinders 410, 510 may be achieved—i.e., the liquid and gas may be at substantially the same pressure.
(48) In operation, various embodiments of the brine electrolysis system 1000 may include a power supply 820 (shown in
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(50) In its basic configuration, the electrolysis stack assembly 310 or chlor-alkali electrolysis stack assembly may comprise one or more membrane cells configured to perform electrolysis on aqueous sodium chloride and water in a membrane cell. Sodium chloride stored in a first chamber 311 of the electrolysis stack assembly 310 may produce chlorine gas 199. Water stored in a second chamber 312 may produce hydrogen gas 299. Additional resulting products of the chlor-alkali process may also include sodium chloride (brine) of decreasing concentration in the first chamber 311 and sodium hydroxide (alkali) of increasing concentration in in the second chamber 312, both of which may outflow the electrolysis stack assembly 310.
(51) Specifically, the first liquid reactant 140 (i.e., sodium chloride having a saturated concentration) may enter the first chamber 311 via first inlet 139. Here, the chloride ions (Cl.sup.−) may be oxidized at anode 300a, thereby losing electrons to become chlorine gas 199:
2Cl.sup.−.fwdarw.Cl.sub.2+2e.sup.−
(52) Additionally, counterion (Na+) within the first chamber 311 may freely flow across the ion-selective membrane 313 and into the second chamber 312. As a result, sodium chloride having a lower concentration may remain in the first chamber 311 and mix with newly added (saturated) sodium chloride entering the first chamber 311 via first inlet 139, resulting with a varying (decreasing) concentration of sodium chloride, as measured by the ionic conductivity meter 115.
(53) At cathode 300b, the second liquid reactant 240 (e.g., water) entering the second chamber 312 via second inlet 239 may be reduced to sodium hydroxide (OH.sup.−) and hydrogen gas 299. Specifically, hydronium ions in chemical equilibrium with the water molecules may be reduced by the electrons provided by the electrolytic current, to hydrogen gas 299, releasing hydroxide ions into the solution:
2H.sub.2O+2e−.fwdarw.H.sub.2+2OH.sup.−
(54) Counterion sodium ions (Na+) passing the ion-permeable ion exchange membrane 313 at the center of the membrane cell may balance the charge with the hydroxide ions to produce sodium hydroxide (NaOH) liquid (aqueous). Therefore, the overall reaction for the electrolysis of brine may be:
2NaCl+2H.sub.2O.fwdarw.Cl.sub.2+H.sub.2+2NaOH
(55) Notably, within the second chamber 312, sodium hydroxide (NaOH) may mix with newly added water, resulting with a varying concentration of sodium hydroxide (NaOH) (mixing with water decreases the concentration of NaOH), as measured by the pH meter 215.
(56) Accordingly, the net process of the chlor-alkali electrolysis process of an aqueous solution of NaCl may be chlorine gas 199, hydrogen gas 299, decreasing concentration of sodium chloride, and increasing concentration of sodium hydroxide, concentrations that may be modulated by inflow of additional sodium chloride (increasing the concentration of sodium chloride) and water (decreasing the concentration of NaOH). In various embodiments, the ionic conductivity meter 115 may measure the depleted concentration of sodium chloride with entrained chlorine gas 199 within the first chamber 311, and as a result, may allow the depleted sodium chloride to exit or outflow the electrolysis stack assembly 310 via the first outlet 135. Also, given that the first outlet 135 may be physically above first inlet 139, chlorine gas 199 may be separated from the depleted sodium chloride via density and thus may also exit the first outlet 135, as shown in
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(58) By way of example, in an embodiment when the first pump 120 is a screw-pump, to regulate the flow of sodium chloride by the first pump 120, a first variable frequency drive (VFD) controller 620 (shown in
(59) Similarly, in the same embodiment, when the second pump 220 is likewise a screw-pump, to regulate the flow of water by the second pump 220, a second VFD controller 720 (shown in
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(61) The ionic conductivity feedback lines 116, 216 may allow transmission of ionic conductivity measurement readings obtained from the tank 150 to the brine process controller 600 and alkali process controller 700 and from there to controller 900. In particular, ionic conductivity feedback line 116 preferably allows transmission of the derived sodium chloride concentration readings obtained from the first interior space 106 of the tank 150 via the ionic conductivity meter 115 to the brine process controller 600. Ionic conductivity feedback line 216, on the other hand, preferably allows transmission of the derived sodium hydroxide concentration readings obtained from the second interior space 107 of the tank 150 via the pH meter 215 to the alkali process controller 700.
(62) The temperature lines 119, 219 may allow transmission of temperature readings obtained from the tank 150 to the controller 900. In particular, temperature line 119 preferably allows transmission of temperature readings obtained from the first interior space 106 of the tank 150 via the brine temperature gauge 118 to the brine process controller 600. Temperature line 219, on the other hand, preferably allows transmission of temperature readings obtained from the second interior space 107 of the tank 150 via the alkali temperature gauge 218 to the alkali process controller 700.
(63) The flow rate lines 197, 297 preferably provide volumetric flow rate readings obtained from the first and second submersible pumps 190, 290 within the tank 150 to the controller 900. In particular, flow rate line 197 preferably allows transmission of volumetric flow rate measurements from the first interior space 106 of the tank 150 via the brine submersible pump flow rate gauge 196 to the brine process controller 600. Flow rate line 297, on the other hand, preferably allows transmission of volumetric flow rate measurements from the second interior space 107 of the tank 150 via the alkali submersible pump flow rate gauge 296 to the alkali process controller 700.
(64) The power supply lines 831, 841 preferably provide DC power transmission to the controller 900 from the power supply controller 800 to the brine electrolysis system 1000. In particular, power supply line 831 preferably provides a positive DC connection to the positive lead flange 830 of the tank 150, whereas power supply 841 provides a negative DC connection to the negative lead flange 840 of the tank 150. Positive and negative lead flanges 830, 840 are preferably in electrical communication with the electrolysis stack assembly 310.
(65) The deflection switch lines 181, 281 preferably provide transmission of diaphragm deflection as result of over-fill readings obtained from the first and second deflection switches 180, 280, respectively, to the brine process controller 600 and electrolysis process controller 700, respectively, and thus to the overall controller 900. In particular, first deflection switch line 181 preferably allows transmission of diaphragm deflection readings obtained from the second interior space 107 of the tank 150 via the first deflection switch 180 to the alkali process controller 700 as the result of over-fill of the second liquid reactant 240 (e.g., water, water/sodium hydroxide liquid combination). Second deflection switch line 281, on the other hand, preferably allows transmission of diaphragm deflection readings obtained from the first interior space 106 of the tank 150 via the second deflection switch 280 to the brine process controller 600 as the result of over-fill of the first liquid reactant 140 (i.e., sodium chloride).
(66) The VFD control lines 111, 211 preferably provide control signal transmission obtained from the controller 900 to the first and second motors 110, 210. In particular, VFD control line 111 preferably provides control signal transmission obtained from the brine process controller 600 to control the first motor 110. VFD control line 211 preferably provides control signal transmission obtained from the alkali process controller 700 to control the second motor 210.
(67) The pressure gauge lines 131, 231 preferably provide transmission of pressure readings obtained from the first and second pressure gauges 130, 230, respectively, to the controller 900. In particular, pressure gauge line 131 preferably allows transmission of pressure readings obtained from the first interior space 106 of the tank 150 via the first pressure gauge 130 to the brine process controller 600. Pressure gauge line 231, on the other hand, preferably allows transmission of pressure readings obtained from the second interior space 107 of the tank 150 via the second pressure gauge 230 to the alkali process controller 700.
(68)
(69) The cabinets 610, 710, 810 may be storage units that hold standard rack-mounted units such as server racks or the like and may be capable of holding and securing various types of electronics and instrumentation equipment Additionally, embodiments of each instrumentation unit may be bolted to the side frames of the cabinet 610, 710, 810 and may have a height of a standard rack-mounted device of 1.75″ (1 U) from top to bottom.
(70) The first and second VFD controllers 620, 720 may be adjustable-speed drives used to control or regulate the motor speed and torque of the first and second motors 110, 210, respectively. In particular, the first and second VFD controllers 620, 720, which may be in electrical communication with the first and second motors 110, 210 via VFD control lines 111, 211, may vary the motor input frequency and voltage in order to control the speed of the first and second motors 110, 210. Thus, the VFD controllers 620, 720 may regulate the amount of fluid entering each interior spaces 106, 107 of the tank 105. As discussed above, the motor input frequency may be adjusted based on the ionic conductivity measurements obtained by the ionic conductivity meter 115 and pH meter 215. Additionally, in an embodiment where the main pump 110 is a screw-pump, the VFD 410 may toggle the rotational direction of the first and second motors 110, 210 between forward and reverse and adjust the speed of the rotation. In this manner, the first and second pumps 120, 220 may regulate the ionic concentration by adding liquid reactants into the tank interior spaces 106,107 or removing liquid reactants from the tank interior spaces 106, 107.
(71) The brine pressure meter 630 and alkali pressure meter 730 may be in communication with the first and second pressure gauges 130, 230, respectively, via pressure gauge lines 131, 231 and are preferably instruments used for collecting pressure readings or data from the first and second pressure gauges 130, 230. The first and second pressure gauges 130, 230 preferably monitor the fluid pressure readings for the interior spaces 106, 107 of the tank 105 and may provide feedback to the first and second VFD controllers 620, 720 to regulate pressure within the tank 105.
(72) The first and second flow meter 640, 740 may be in communication with the brine submersible pump flow rate gauge 1% and the alkali submersible pump flow rate gauge 296, respectively, via flow rate lines 197, 297 and are preferably instruments that collect volumetric flow rate measures of the tank 150. Based on the volumetric flow rates, the brine process controller 600 and alkali process controller 700 may adjust the pumping action of the first and second submersible pumps 190, 290 to control the amount of heat generated by the electrolysis stack assembly 310. The brine process controller 600 and alkali process controller 700 may also inactivate the electrolysis stack assembly 310 when the liquid reactants are outside the manufacturer specification of temperature operating range.
(73) The first and second diaphragm deflection switch meters 650, 750 may be in communication with the first and second deflection switches 180, 280 via deflection switch lines 181, 281 and may be configured for determining whether fluid or volume has reached a certain threshold within the first and second interior spaces 106, 107 of the tank 150. Given that the first and second deflection switches 180, 280 may determine whether a fluid has reached a certain volume within the tank 150, these fluid measurements may trigger the controller 900 to provide feedback control to the first and second motors 110, 210, and as a result, the first and second pumps 120, 220. In this manner, the brine electrolysis system 1000 may maintain volume of the liquid reactants within the tank 150.
(74) The brine temperature meter 660 and alkali temperature meter 760 may be in communication with the brine temperature gauge 118 and alkali temperature gauge 218, respectively, via temperature lines 119, 219, and are preferably instruments used for collecting temperature measurements of the liquid reactants within the tank 150. Specifically, the brine temperature meter 660 may obtain temperature measurements of sodium chloride within the first interior space 106 of the tank 150 via the brine temperature gauge 118. The alkali temperature meter 760, on the other hand, may obtain temperature measurements of water within the second interior space 107 of the tank 150 via the alkali temperature gauge 218. Importantly, not shown, the liquid reactant brine and water may be refrigerated in the first and second liquid storage tanks 100, 200 to reduce absolute temperature rise within the first and second interior spaces 106,107 upon operation of the electrolysis stack assembly 310.
(75) The brine concentration meter 670 and alkali concentration meter 770 may be in communication with the ionic conductivity meter 115 and pH meter 215, respectively, via ionic concentration feedback lines 116, 216, and are preferably instruments used for collecting ionic conductivity measurements converted to concentration readings of the liquid reactants within the tank 150. Specifically, the brine concentration meter 670 may obtain ionic conductivity measurements of sodium chloride for conversion to concentration reading within the first interior space 106 of the tank 150 via the ionic conductivity meter 115. The alkali concentration meter 770, on the other hand, may obtain ionic conductivity measurements for conversion to concentration readings of sodium hydroxide within the tank 150 within the second interior space 107 of the tank 150 via the pH meter 215.
(76) Finally, the power supply 820 may be device or component that supplies power to the brine electrolysis system 1000. The power supply 820 is preferably coupled to the electrolysis stack assembly 310 via the power supply lines 831, 841 and positive and negative lead flanges 830,840 for converting the supplied power to the correct voltage and current, in applying the correct potential difference across the end plates of the electrolysis stack assembly 310.
(77) The foregoing description of the embodiments of the brine electrolysis system for producing pressurized chlorine and hydrogen gases has been presented for the purposes of illustration and description. While multiple embodiments are disclosed, other embodiments will become apparent to those skilled in the art from the above detailed description. As will be realized, these embodiments are capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present disclosure. Accordingly, the detailed description is to be regarded as illustrative in nature and not restrictive.
(78) Although embodiments of the brine electrolysis system are described in considerable detail, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of versions included herein.
(79) Except as stated immediately above, nothing which has been stated or illustrated is intended or should be interpreted to cause a dedication of any component, step, feature, object, benefit, advantage, or equivalent to the public, regardless of whether it is or is not recited in the claims. The scope of protection is limited solely by the claims that now follow, and that scope is intended to be broad as is reasonably consistent with the language that is used in the claims. The scope of protection is also intended to be broad to encompass all structural and functional equivalents.