Reverse electrodialysis-based water electrolysis apparatus

Abstract

The present invention relates to a reverse electrodialysis-based water electrolysis apparatus capable of producing hydrogen and oxygen with a small amount of electricity consumption and generating electricity in an eco-friendly manner by introducing an exchange membrane having an electrode layer bonded to the surface thereof. The reverse electrodialysis-based water electrolysis apparatus of the present invention may be economically feasible by producing hydrogen and oxygen with a small amount of electricity consumption, and can reduce environmental pollution by generating electricity in an eco-friendly manner. In addition, hydrogen can be produced by using seawater, thereby securing economic feasibility.

Description

Reverse electrodialysis-based water electrolysis device

[0001] The present invention relates to a reverse electrodialysis-based water electrolysis device capable of producing hydrogen and oxygen with a small amount of electricity consumption and producing electricity in an environmentally friendly manner by introducing an exchange membrane having an electrode layer bonded to its surface.

[0002] With technological advancements and the rapid increase in fossil fuel consumption, problems such as accelerated global warming and environmental destruction have arisen, raising the need for eco-friendly energy sources to replace fossil fuels. Hydrogen, a leading example of eco-friendly energy, is attracting attention as a clean, eco-friendly energy source that can replace coal and oil due to its low emissions when burned. It is considered a future growth engine.

[0003] Water electrolysis (WE) is an electrochemical technology that generates hydrogen and oxygen by electrolyzing water and transporting ions across a membrane. Representative methods include alkaline water electrolysis, cation exchange membrane (CEM) electrolysis, and anion exchange membrane (ANEM) electrolysis. While these technologies can produce hydrogen, conventional WE technologies consume significant amounts of electricity during the electrolysis process, leading to high production costs and low energy efficiency. Therefore, research is urgently needed to reduce the electricity consumed during WE and achieve more efficient hydrogen production.

[0004] Meanwhile, reverse-electrodialysis (RED) is a system that generates power by recovering the energy of the difference in salinity or concentration that occurs during the mixing of two fluids with different concentrations, such as seawater and freshwater, in the form of electrical energy. It is a power generation method that directly converts the chemical energy generated when ions dissolved in seawater (salt water) move through an ion exchange membrane into electrical energy.

[0005] Against this backdrop, the inventors of the present invention have conducted research efforts to develop a device for generating electric energy in an environmentally friendly manner while reducing electricity consumption in the process of producing hydrogen using electrolysis, and as a result, have completed the present invention by manufacturing a water electrolysis device based on reverse electrodialysis.

[0006] [Prior Art Literature]

[0007] Korean Patent Publication No. 10-2023-0117947

[0008] The present invention aims to solve the above-mentioned problems and other problems related thereto.

[0009] An exemplary object of the present invention is to provide a device for producing hydrogen and oxygen with a reduced amount of electricity by manufacturing a water electrolysis device based on reverse electrodialysis and simultaneously generating electric energy by reverse electrodialysis using the generated electric energy.

[0010] The technical problem to be achieved according to the technical idea of ​​the invention disclosed in this specification is not limited to the problem to solve the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] As one aspect for achieving the above purpose, one example of the present invention is

[0012] Cathode electrode and anode electrode facing each other;

[0013] An ion exchange membrane stack in which anion exchange membranes and cation exchange membranes are alternately arranged so that a first path through which a first solution flows and a second path through which a second solution containing a salt having a higher concentration than the first solution flows are divided into multiple paths, and is arranged between the cathode electrode and the anode electrode; and

[0014] A water electrolysis device is provided, comprising an electrode layer bonded to the surface of the anion exchange membrane or cation exchange membrane.

[0015] As another aspect for achieving the above purpose, one example of the present invention is

[0016] Cathode electrode and anode electrode facing each other;

[0017] An ion exchange membrane stack in which anion exchange membranes, cation exchange membranes, and osmosis membranes are alternately arranged so that a first path through which a first solution flows, a second path through which a second solution containing a higher concentration of salt than the first solution flows, and a third path through which seawater flows are divided into multiple paths, arranged between the cathode electrode and the anode electrode;

[0018] A water electrolysis device is provided, comprising an electrode layer bonded to the surface of the anion exchange membrane or the cation exchange membrane.

[0019] The reverse electrodialysis-based water electrolysis device of the present invention produces hydrogen and oxygen with minimal electricity consumption, ensuring economic feasibility. Furthermore, it generates electricity in an environmentally friendly manner, reducing environmental pollution. Furthermore, its ability to produce hydrogen using seawater ensures economic feasibility.

[0020] Meanwhile, the scope of the present invention is not limited by the effects described above.

[0021]

[0022]

[0023] Figure 1 is a cross-sectional view of a water electrolysis device according to one embodiment of the present invention.

[0024] Figure 2 is a drawing showing the combined state of the electrolysis device illustrated in Figure 1 (left) and the state in which an anion exchange membrane, a cation exchange membrane, and a closed gasket are laminated in multiple stages (right).

[0025] Figure 3 is a drawing showing the combined state of the electrolysis device illustrated in Figure 1 (left) and the state in which an anion exchange membrane, a cation exchange membrane, and an open gasket are laminated in multiple stages (right).

[0026] Figure 4 is a cross-sectional view of a water electrolysis device according to another embodiment of the present invention.

[0027] Figure 5 is a drawing showing the combined state of the electrolysis device illustrated in Figure 4 (left) and the state in which an anion exchange membrane, a cation exchange membrane, and a closed gasket are laminated in multiple stages (right).

[0028] Figure 6 is a drawing showing the combined state of the electrolysis device shown in Figure 4 (left) and the state in which the anion exchange membrane, cation exchange membrane, and open gasket are laminated in multiple stages (right).

[0029] Figure 7 is a cross-sectional view of a water electrolysis device according to another embodiment of the present invention.

[0030] Figure 8 is a drawing showing the combined state of the electrolysis device illustrated in Figure 7 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and a closed gasket are laminated in multiple stages (right).

[0031] Figure 9 is a drawing showing the combined state of the electrolysis device illustrated in Figure 7 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and an open gasket are laminated in multiple stages (right).

[0032] Figure 10 is a cross-sectional view of a water electrolysis device according to another embodiment of the present invention.

[0033] Figure 11 is a drawing showing the combined state of the electrolysis device illustrated in Figure 10 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and a closed gasket are laminated in multiple stages (right).

[0034] Figure 12 is a drawing showing the combined state of the electrolysis device illustrated in Figure 10 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and an open gasket are laminated in multiple stages (right).

[0035] Figure 13 is a cross-sectional view of a water electrolysis device according to another embodiment of the present invention.

[0036] Figure 14 is a drawing showing the combined state of the electrolysis device shown in Figure 13 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and a closed gasket are laminated in multiple stages (right).

[0037] Figure 15 is a drawing showing the combined state of the electrolysis device shown in Figure 13 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and an open gasket are laminated in multiple stages (right).

[0038] Fig. 16 is a cross-sectional view of a water electrolysis device according to another embodiment of the present invention.

[0039] Figure 17 is a drawing showing the combined state of the electrolysis device shown in Figure 16 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and a closed gasket are laminated in multiple stages (right).

[0040] Figure 18 is a drawing showing the combined state of the electrolysis device illustrated in Figure 16 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and an open gasket are laminated in multiple stages (right).

[0041] Figure 19 shows the results of confirming the energy consumption of a water electrolysis device according to one embodiment of the present invention.

[0042] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concept of a term to best explain his or her invention, they should be interpreted in a way that conforms to the technical spirit of the present invention.

[0043] In addition, regardless of the drawing symbol, identical or corresponding components are given identical or similar reference numbers and redundant descriptions thereof are omitted, and for the convenience of explanation, the size and shape of each component depicted may be exaggerated or reduced.

[0044] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0045] As one aspect for achieving the above purpose, the present invention

[0046] Cathode electrode and anode electrode facing each other;

[0047] An ion exchange membrane stack in which anion exchange membranes and cation exchange membranes are alternately arranged so that a first path through which a first solution flows and a second path through which a second solution containing a salt having a higher concentration than the first solution flows are divided into multiple paths, and is arranged between the cathode electrode and the anode electrode; and

[0048] A water electrolysis device is provided, comprising an electrode layer bonded to the surface of the anion exchange membrane or cation exchange membrane.

[0049] According to the United States Geological Survey's classification of water quality by salt concentration, 'salt water' or 'sea water' generally refers to a solution with a salt concentration of 35,000 mg / L or more, which is the salt (mainly NaCl) concentration of sea water, 'brackish water' refers to a solution with a salt concentration of about 1,000 to 10,000 mg / L, and 'fresh water' refers to a solution with a salt concentration of 0 to 1,000 mg / L.

[0050] In the present invention, the first solution may mean a low-concentration solution having a relatively lower concentration than the second solution, and may mean, for example, fresh water, brackish water, or seawater.

[0051] In the present invention, the second solution may refer to a high-concentration solution introduced for concentration difference or salinity difference power generation, and may refer to, for example, a brine mixed with seawater, seawater desalination concentrate, potassium hydroxide, ammonium hydroxide, or sodium hydroxide.

[0052] In one embodiment of the present invention, the electrode layer may be configured by bonding a cathode (reduction reaction, cathode) and an anode (oxidation reaction, anode) to both surfaces of an anion exchange membrane or a cation exchange membrane. The electrode layer functions to transfer ions through the ion exchange membrane as electrons released from the positive electrode move to the negative electrode.

[0053] For example, the support of the cathode may be carbon or nickel.

[0054] For example, the catalyst of the cathode may be, but is not limited to, a noble metal catalyst such as platinum (Pt), a non-noble metal catalyst such as Ni3S, NiFeS, NiFeCoS, MoS2, Ni2N, MoN2, MoP, Ni3P or NiMoP, or a catalyst such as RuNiMoS or PtNiMoS, which is a combination of noble metals and non-noble metals.

[0055] For example, the electrode layer can be bonded to both surfaces of an anion exchange membrane or a cation exchange membrane in a zero-gap manner.

[0056] In general, reverse electrodialysis is based on the principle of generating voltage by the movement of ions due to the difference in salinity across an ion exchange membrane, while electrolysis is based on the principle of moving ions by applying voltage across an ion exchange membrane. Therefore, there is no known research that integrates reverse electrodialysis and electrolysis.

[0057] The present invention relates to a device that integrates reverse electrodialysis and water electrolysis, and when the direction of flow of ions generated by applying voltage in water electrolysis is aligned with the direction of flow of ions that generate voltage in reverse electrodialysis, the magnitude of the applied voltage is reduced while the amount of ion flow increases at the same time, so that the amount of current density can be increased (current density due to applied voltage + current density due to concentration difference), thereby creating a synergy effect.

[0058] Hereinafter, a water electrolysis device according to one embodiment of the present invention will be described with reference to the attached drawings.

[0059] First, referring to FIG. 1, a water electrolysis device (10) according to a first embodiment of the present invention will be described. The water electrolysis device according to the first embodiment of the present invention includes an anode electrode (100) and a cathode electrode (200) which are installed to face each other. An ion exchange membrane stack (300) is arranged between the anode electrode (100) and the cathode electrode (200). The ion exchange membrane stack (300) is arranged alternately with anion exchange membranes (400) and cation exchange membranes (500) so as to be divided into a first channel (310) through which a low-concentration first solution flows and a second channel (320) through which a second solution having a higher concentration than the first solution flows. An electrode layer (600) is bonded to the surface of the anion exchange membrane (400).

[0060] The above electrode layer (600) is composed of a combination of a positive electrode and a negative electrode, and electrons emitted from the positive electrode move to the negative electrode, performing the role of transferring ions through the ion exchange membrane.

[0061] A first flow path (310) can be formed between the anion exchange membrane (400) to which the electrode layer (600) is bonded and the cation exchange membrane (500) adjacent from the anion exchange membrane (400) toward the anode electrode (100).

[0062] A second flow path (320) can be formed between the anion exchange membrane (400) to which the electrode layer (600) is bonded and the cation exchange membrane (500) adjacent from the anion exchange membrane (400) toward the cathode electrode (200).

[0063] In one embodiment of the present invention, at least one gasket (800) is mounted on each of the two ends of the cation exchange membrane (500) and the anion exchange membrane (400), and the gaskets (800) may be arranged to intersect each other at the two ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first channel (310) through which a first solution flows and a second channel (320) through which a second solution flows.

[0064] In the present invention, a spacer having an open area inside the gasket (800) can be used to prevent contact between the cation exchange membrane (500) and the anion exchange membrane (400) and secure a flow path.

[0065] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. The electrode solution may be fresh water or a separate anode electrode solution.

[0066] At this time, water (H2O) in the second flow path (320) is reduced to hydrogen ions (H2O) by a reduction reaction on the negative electrode surface of the electrode layer (600). + ) and hydroxide ions (OH - ) is decomposed into hydrogen ions (H + ) is an electron (e) emitted from the positive electrode of the electrode layer (600). - ) is generated as hydrogen gas, and the generated hydroxide ions (OH - ) moves to the first flow path (310) through the anion exchange membrane (400). The moved hydroxide ions (OH - ) is formed by oxidation reaction on the positive electrode surface of the electrode layer (600), resulting in oxygen (O2), water (H2O) and electrons (e). - ) is generated, and the generated electrons move to the second flow (320) and become hydrogen ions (H + ) reacts with water to produce hydrogen (H2).

[0067] In addition, by reverse electrodialysis, the anions of the second solution move to the first channel (310) toward the anode electrode (100) through the anion exchange membrane to which the electrode layer (600) is bonded, and the cations of the second solution move to the first channel (310) through the cation exchange membrane (500) toward the cathode electrode (200), and voltage and current are generated by the movement of the ions. In addition, electricity is generated as the electrons transferred to the anode electrode (100) move to the cathode electrode (200).

[0068] FIG. 2 and FIG. 3 are drawings showing the combined state (left) of the electrolysis device (10) illustrated in FIG. 1 and the state (right) in which an anion exchange membrane (400), a cation exchange membrane (500), and a gasket (800) are stacked in multiple stages. The gasket of FIG. 2 is of a closed type and the gasket of FIG. 3 is of an open type. The closed gasket is suitable for manufacturing unit stacks, and the open gasket is suitable for modularizing multiple stacks.

[0069] Next, with reference to FIG. 4, a water electrolysis device (20) according to a second embodiment of the present invention will be described. The water electrolysis device (20) according to the second embodiment of the present invention includes a cathode electrode (200) and an anode electrode (100) that are installed to face each other. An ion exchange membrane stack (300) is arranged between the cathode electrode (200) and the anode electrode (100). The ion exchange membrane stack (300) is arranged alternately with anion exchange membranes (400) and cation exchange membranes (500) so as to be divided into a first channel (310) through which a low-concentration first solution flows and a second channel (320) through which a second solution having a higher concentration than the first solution flows. An electrode layer (600) is bonded to the surface of the cation exchange membrane (500).

[0070] A first flow path (310) can be formed between a cation exchange membrane (500) to which an electrode layer (600) is bonded and an anion exchange membrane (400) adjacent from the cation exchange membrane (500) toward the cathode electrode (200).

[0071] The electrode layer (600) is composed of a combination of a positive electrode and a negative electrode, and electrons emitted from the positive electrode move to the negative electrode, performing the role of transferring ions through the ion exchange membrane.

[0072] A second flow path (320) can be formed between the cation exchange membrane (500) to which the electrode layer (600) is bonded and the anion exchange membrane (400) adjacent from the cation exchange membrane (500) toward the anode electrode (100).

[0073] In one embodiment of the present invention, at least one gasket (800) is mounted on each of the two ends of the cation exchange membrane (500) and the anion exchange membrane (400), and the gaskets (800) may be arranged to intersect each other at the two ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first channel (310) through which a first solution flows and a second channel (320) through which a second solution flows.

[0074] In the present invention, a spacer having an open area inside the gasket can be used to prevent contact between the cation exchange membrane (500) and the anion exchange membrane (400) and secure a flow path.

[0075] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. The electrode solution may be fresh water or a separate anode electrode solution.

[0076] At this time, water (H2O) in the second flow path (320) is converted into oxygen (O2) and water by oxidation reaction on the positive electrode surface of the electrode layer (600) and electrons (e - ) and simultaneously release hydrogen ions (H + ) moves to the first flow path (310) through the cation exchange membrane (500). At this time, hydrogen ions (H) are produced by a reduction reaction on the negative electrode surface of the electrode layer (600). + ) is additionally generated, and at the same time hydroxide ions (OH - ) is decomposed into hydrogen ions (H) transferred from the cation exchange membrane (500). +) and hydrogen ions (H) produced at the negative electrode of the electrode layer (600) + ) is the electron (e) flowing into the negative electrode of the electrode layer (600). - ) is converted into hydrogen gas (H2). The produced hydroxide ions (OH - ) is transferred to the second channel (320) toward the cathode electrode (200) through the anion exchange membrane (400), and the anions in the second channel (320) are transferred to the first channel toward the anode electrode (100) through the anion exchange membrane (400).

[0077] In addition, by reverse electrodialysis, the cations of the second solution move to the first channel (310) through the cation exchange membrane (500) to which the electrode layer (600) is bonded, and the anions of the second solution move to the first channel (310) toward the anode electrode (100) through the anion exchange membrane (400) toward the anode electrode (100), and voltage and current are generated by the movement of the ions. In addition, electricity is generated as the electrons transferred to the anode electrode (100) move to the cathode electrode (200).

[0078] FIG. 5 and FIG. 6 are drawings showing the combined state (left) of the electrolysis device (20) illustrated in FIG. 4 and the state (right) in which an anion exchange membrane (400), a cation exchange membrane (500), and a gasket (800) are laminated in multiple stages. The gasket in FIG. 5 is a closed type and the gasket in FIG. 6 is an open type.

[0079] Closed gaskets are suitable for manufacturing unit stacks, while open gaskets are suitable for modularizing multiple stacks.

[0080] As another aspect for achieving the above purpose, the present invention

[0081] A cathode electrode (200) and an anode electrode (100) facing each other;

[0082] An ion exchange membrane stack (300) arranged between the cathode electrode (200) and the anode electrode (100); wherein anion exchange membranes (400), cation exchange membranes (500), and osmosis membranes (700) are alternately arranged so that a first path (310) through which a first solution flows, a second path (320) through which a second solution containing a higher concentration of salt than the first solution flows, and a third path (330) through which seawater flows are divided into multiple parts;

[0083] A water electrolysis device is provided, which includes an electrode layer (600) bonded to the surface of the anion exchange membrane (400) or the cation exchange membrane (500).

[0084] Referring to FIG. 7, a water electrolysis device (30) according to a third embodiment of the present invention will be described. The water electrolysis device according to the third embodiment of the present invention includes a cathode electrode (200) and an anode electrode (100) that face each other. An ion exchange membrane stack (300) is arranged between the cathode electrode (200) and the anode electrode (100). The ion exchange membrane stack (300) is alternately arranged with an anion exchange membrane (400), a cation exchange membrane (500), and an osmosis membrane (700) so as to be divided into a first channel (310) through which a first solution flows, a second channel (320) through which a second solution containing a salt concentration higher than that of the first solution flows, and a third channel (330) through which seawater flows. An electrode layer (600) is bonded to the surface of the anion exchange membrane (400). The above osmotic membrane (700) is located between the anion exchange membrane (400) and the cation exchange membrane (500) which is positioned adjacent to the anion exchange membrane (400) but facing the cathode electrode (200).

[0085] A first flow path (310) can be formed between the anion exchange membrane (400) to which the electrode layer (600) is bonded and the cation exchange membrane (500) adjacent from the anion exchange membrane (400) toward the anode electrode (100).

[0086] A second flow path (320) can be formed between the anion exchange membrane (400) to which the electrode layer (600) is bonded and the osmotic membrane (700) adjacent to the anion exchange membrane (400).

[0087] The third channel (330) is formed between the osmosis membrane (700) and the cation exchange membrane (500) adjacent to the osmosis membrane (700). Since seawater flowing in the third channel (330) may corrode the catalyst of the electrode layer (600) if it comes into direct contact with the electrode layer (600) bonded to the surface of the anion exchange membrane (400), the osmosis membrane (700) is placed between the anion exchange membrane (400) and the third channel (330) to prevent direct contact.

[0088] In one embodiment of the present invention, at least one gasket (800) is mounted on each of the two ends of the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700), and the gaskets (800) may be arranged to intersect each other at the two ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first channel (310) through which a first solution flows, a second channel (320) through which a second solution flows, and a third channel (330) through which a third solution flows.

[0089] In the present invention, a spacer having an open area inside the gasket can be used to prevent contact between the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700) and secure a flow path.

[0090] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. The electrode solution may be fresh water or a separate anode electrode solution.

[0091] When water (H20) from the seawater of the third flow path (330) moves to the second flow path (320) through the osmotic membrane (700), the moved water is converted into hydrogen ions (H20) by a reduction reaction on the negative electrode surface of the electrode layer (600). + ) and hydroxide ions (OH - ) is decomposed into hydrogen ions (H+ ) electrons (e) emitted from the positive electrode of the electrode layer (600) - ) is received, hydrogen gas (H2) is generated, and the generated hydroxide ions (OH - ) moves to the first flow path (310) through the anion exchange membrane (400). The moved hydroxide ions (OH - ) is converted into oxygen (O2) and water by oxidation reaction on the positive electrode surface of the electrode layer (600), and electrons (e - ) is emitted. The generated electrons (e - ) moves to the second euro (320) and hydrogen ions (H + ) reacts with water to produce hydrogen (H2).

[0092] In addition, by reverse electrodialysis, cations of the third solution (seawater) move to the first channel through the cation exchange membrane (500) toward the cathode electrode (200). Anions of the second solution move to the first channel (310) through the anion exchange membrane (400) to which the electrode layer (600) is bonded. Voltage and current are generated by the movement of these ions. In addition, electricity is generated as electrons transferred to the anode electrode (100) move to the cathode electrode (200). At this time, cations that move through the cation exchange membrane (500) toward the cathode electrode (200) can directly contact the anion exchange membrane (400), but do not cause corrosion.

[0093] FIG. 8 and FIG. 9 are drawings showing the combined state of the electrolysis device (30) shown in FIG. 7 (left) and the state in which the anion exchange membrane (400), the cation exchange membrane (500), the osmotic membrane (700), and the gasket (800) are laminated in multiple stages (right). The gasket of FIG. 8 is a closed type and the gasket of FIG. 9 is an open type.

[0094] Closed gaskets are suitable for manufacturing unit stacks, while open gaskets are suitable for modularizing multiple stacks.

[0095] Referring to FIG. 10, a water electrolysis device (40) according to a fourth embodiment of the present invention will be described. The water electrolysis device according to the fourth embodiment of the present invention includes a cathode electrode (200) and an anode electrode (100) that face each other. An ion exchange membrane stack (300) is arranged between the cathode electrode (200) and the anode electrode (100). The ion exchange membrane stack (300) is alternately arranged with an anion exchange membrane (400), a cation exchange membrane (500), and an osmosis membrane (700) so as to be divided into a first channel (310) through which a first solution flows, a second channel (320) through which a second solution containing a salt concentration higher than that of the first solution flows, and a third channel (320) through which seawater flows. An electrode layer (600) is bonded to the surface of the cation exchange membrane (500). The above osmotic membrane (700) is located between the cation exchange membrane (500) and the anion exchange membrane (400) which is positioned adjacent to the cation exchange membrane (500) but facing the anode electrode (100).

[0096] A first flow path (310) can be formed between a cation exchange membrane (500) to which an electrode layer (600) is bonded and an anion exchange membrane (400) adjacent from the cation exchange membrane (500) toward the cathode electrode (200).

[0097] A second flow path (320) can be formed between the cation exchange membrane (500) to which the electrode layer (600) is bonded and the osmotic membrane (700) adjacent to the cation exchange membrane (500).

[0098] In one embodiment of the present invention, at least one gasket (800) is mounted on each of the two ends of the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700), and the gaskets (800) may be arranged to intersect each other at the two ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first channel (310) through which a first solution flows, a second channel (320) through which a second solution flows, and a third channel (330) through which a third solution flows.

[0099] In the present invention, a spacer having an open area inside the gasket can be used to prevent contact between the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700) and secure a flow path.

[0100] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. The electrode solution may be fresh water or a separate anode electrode solution.

[0101] The third flow path (330) is formed between the osmotic membrane (700) and the anion exchange membrane (400) adjacent to the osmotic membrane (700). At this time, when water (H2O) from the seawater of the third flow path (330) moves to the second flow path (320) through the osmotic membrane (700), the water (H2O) in the second flow path (320) is converted into oxygen (O2) and water (H2O) by an oxidation reaction on the positive electrode surface of the electrode layer (600) and electrons (e - ) is released. At this time, hydrogen ions are additionally produced by a reduction reaction on the negative electrode surface of the electrode layer (600) in the first euro (310), and at the same time, hydroxide ions (OH - ) is decomposed into hydrogen ions (H) transferred from the second channel (320) to the first channel (310) through the cation exchange membrane (500). + ) and hydrogen ions (H) produced at the negative electrode of the electrode layer (600) in the first euro (310) + ) is the electron (e) flowing into the negative electrode of the electrode layer (600). - ) is converted into hydrogen gas (H2). Hydroxide ions (OH) produced in the first flow - ) is transferred to the third channel (330) through the anion exchange membrane (400), and the anion of the third channel (330) is transferred to the first channel (310) through the anion exchange membrane (400). At this time, the anion Cl is transferred to the reduction electrode of the electrode layer (600) of the cation exchange membrane (500). - When they come into contact, the first solution is alkalized by the reduction electrode reaction. P H>9) can be, but Cl- The ions play a positive role in returning the alkaline first solution to neutrality, preventing the electrode from corroding.

[0102] In addition, by reverse electrodialysis, the cations of the second solution move to the first channel (310) through the cation exchange membrane (500) to which the electrode layer (600) is attached. The anions of the third solution (seawater) move to the first channel (310) through the anion exchange membrane (400) toward the anode electrode (100). Voltage and current are generated through the movement of these ions. In addition, electricity is generated as the electrons transferred to the anode electrode (100) move to the cathode electrode (200).

[0103] In one embodiment of the present invention, an osmotic membrane (700) may be arranged between each of the cation exchange membrane (500) and the anion exchange membrane (400).

[0104] FIG. 11 and FIG. 12 are drawings showing the combined state (left) of the electrolysis device (40) illustrated in FIG. 10 and the state (right) in which an anion exchange membrane (400), a cation exchange membrane (500), an osmotic membrane (700), and a gasket (800) are laminated in multiple stages. The gasket in FIG. 11 is a closed type and the gasket in FIG. 12 is an open type.

[0105] Closed gaskets are suitable for manufacturing unit stacks, while open gaskets are suitable for modularizing multiple stacks.

[0106] Referring to FIG. 13, a water electrolysis device (50) according to a fifth embodiment of the present invention will be described. The water electrolysis device according to the fifth embodiment of the present invention includes a cathode electrode (200) and an anode electrode (100) that face each other. An ion exchange membrane stack (300) is arranged between the cathode electrode (200) and the anode electrode (100). The ion exchange membrane stack (300) is alternately arranged with an anion exchange membrane (400), a cation exchange membrane (500), and an osmosis membrane (700) so as to be divided into a first channel (310) through which a first solution flows, a second channel (320) through which a second solution (320) containing a salt concentration higher than that of the first solution flows, and a third channel (330) through which seawater flows. An electrode layer (600) is bonded to the surface of the anion exchange membrane (400). The above osmotic membrane (700) is arranged between the cation exchange membrane (500) and the anion exchange membrane (400).

[0107] A first flow path (310) can be formed between a cation exchange membrane (500) and an osmotic membrane (700) adjacent to the cathode electrode (200) from the cation exchange membrane (500).

[0108] A second channel (320) may be formed between the anion exchange membrane (400) to which the electrode layer (600) is bonded and the adjacent osmotic membrane (700). At this time, the second channel (320) formed between the osmotic membrane (700) adjacent in the direction of the anode electrode (100) of the anion exchange membrane (400) is referred to as the 2-1 channel (321), and the second channel (320) formed between the osmotic membrane (700) adjacent in the direction of the cathode electrode (200) of the anion exchange membrane (400) is referred to as the 2-2 channel (322).

[0109] A third flow path (330) can be formed between the osmotic membrane (700) and the cation exchange membrane (500) adjacent to the cathode electrode (200) from the osmotic membrane (700).

[0110] In one embodiment of the present invention, at least one gasket (800) is mounted on each of the two ends of the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700), and the gaskets (800) may be arranged to intersect each other at the two ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first channel (310) through which a first solution flows, a second channel (320) through which a second solution flows, and a third channel (330) through which a third solution flows.

[0111] In the present invention, a spacer having an open area inside the gasket can be used to prevent contact between the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700) and secure a flow path.

[0112] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. The electrode solution may be fresh water or a separate anode electrode solution.

[0113] At this time, water (H2O) in the first flow path (310) moves to the second-first flow path (321) through the osmotic membrane (700), and water (H2O) moves from seawater in the third flow path (330) to the second-second flow path (322) through the osmotic membrane (700).

[0114] The water that moved to the 2nd-2nd euro (322) is reduced to hydrogen ions (H) by a reduction reaction on the negative electrode surface of the electrode layer (600). + ) and hydroxide ions (OH - ) is decomposed into hydrogen ions, and the generated hydrogen ions are released from the positive electrode of the electrode layer (600) as electrons (e - ) is released as hydrogen gas (H2), and the generated hydroxide ions (OH - ) moves to the second-1 (321) path through the anion exchange membrane (400). The moved hydroxide ions (OH - ) is converted into oxygen (O2) and water (H2O) by oxidation reaction on the positive electrode surface of the electrode layer (600), and electrons (e -) occurs. The water (H2O) that moves to the 2-1 flow path (321) is used to produce oxygen in the oxidation reaction. The electrons that are generated move to the 2-2 flow path (322) and become hydrogen ions (H + ) reacts with water to produce hydrogen (H2).

[0115] In addition, by reverse electrodialysis, cations of the third solution (seawater) move through the cation exchange membrane (500) toward the cathode electrode (200), and anions of the 2-2 path (322) move to the 2-1 path (321) through the anion exchange membrane (400) to which the electrode layer (600) is attached. Voltage and current are generated by the movement of these ions. In addition, electricity is generated as electrons transferred to the anode electrode (100) move to the cathode electrode (200).

[0116] FIG. 14 and FIG. 15 are drawings showing the combined state (left) of the electrolysis device (50) illustrated in FIG. 13 and the state (right) in which an anion exchange membrane (400), a cation exchange membrane (500), an osmotic membrane (700), and a gasket (800) are laminated in multiple stages. The gasket of FIG. 14 is a closed type and the gasket of FIG. 15 is an open type.

[0117] Closed gaskets are suitable for manufacturing unit stacks, while open gaskets are suitable for modularizing multiple stacks.

[0118] Referring to FIG. 16, a water electrolysis device (60) according to a sixth embodiment of the present invention will be described. The water electrolysis device according to the sixth embodiment of the present invention includes a cathode electrode (200) and an anode electrode (100) that face each other. An ion exchange membrane stack (300) is arranged between the cathode electrode (200) and the anode electrode (100). The ion exchange membrane stack (300) is alternately arranged with an anion exchange membrane (400), a cation exchange membrane (500), and an osmosis membrane (700) so as to be divided into a first channel (310) through which a first solution flows, a second channel (320) through which a second solution containing a salt concentration higher than that of the first solution flows, and a third channel (330) through which seawater flows. An electrode layer (600) is bonded to the surface of the cation exchange membrane (500). The above osmotic membrane (700) is arranged between the cation exchange membrane (500) and the anion exchange membrane (400).

[0119] A first flow path (310) can be formed between the anion exchange membrane (400) and the osmotic membrane (700) adjacent to the anode electrode (100) from the cation exchange membrane (500).

[0120] A second channel (320) may be formed between the cation exchange membrane (500) to which the electrode layer (600) is bonded and the adjacent osmotic membrane (700). At this time, the second channel (320) formed between the osmotic membrane (700) adjacent in the direction of the anode electrode (100) of the cation exchange membrane (500) is referred to as the 2-1 channel (321), and the second channel (320) formed between the osmotic membrane (700) adjacent in the direction of the cathode electrode (200) of the cation exchange membrane (500) is referred to as the 2-2 channel (322).

[0121] A third flow path (330) can be formed between the osmotic membrane (700) and the anion exchange membrane (400) adjacent to the osmotic membrane (700) in the direction of the anode electrode (100).

[0122] In one embodiment of the present invention, at least one gasket (800) is mounted on each of the two ends of the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700), and the gaskets (800) may be arranged to intersect each other at the two ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first channel (310) through which a first solution flows, a second channel (320) through which a second solution flows, and a third channel (330) through which a third solution flows.

[0123] In the present invention, a spacer having an open area inside the gasket can be used to prevent contact between the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700) and secure a flow path.

[0124] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. The electrode solution may be fresh water or a separate anode electrode solution.

[0125] At this time, water (H2O) from the seawater of the third flow path (330) moves to the second-first flow path (321) through the osmotic membrane (700), and water (H2O) from the first flow path (310) moves to the second-second flow path (322) through the osmotic membrane (700).

[0126] Water (H2O) in the 2nd-1st euro (321) is converted into oxygen (O2) and water (H2O) by oxidation reaction on the positive electrode surface of the electrode layer (600), and electrons (e - ) and at the same time release hydrogen ions (H + ) moves to the 2-2 channel (322) through the cation exchange membrane (500). At this time, hydrogen ions (H) in the 2-2 channel (322) are reduced by a reduction reaction on the negative electrode surface of the electrode layer (600). + ) is additionally produced, and at the same time hydroxide ions (OH - ) is decomposed into hydrogen ions (H) transferred to the second-second channel (322) through the cation exchange membrane (500). + ) and hydrogen ions (H ) produced on the negative electrode surface +) is an electron (e) flowing in from the negative electrode of the electrode layer (600). - ) is received and converted into hydrogen gas (H2). In addition, the anions of the third channel (330) are transferred to the first channel (310) through the anion exchange membrane (400).

[0127] By reverse electrodialysis, the movement direction of the cations of the second solution is determined according to the concentration difference between the 2-1 flow path (321) and the 2-2 flow path (322).

[0128] Anions in the third solution (seawater) move through the anion exchange membrane (400) toward the anode electrode (100), and voltage and current are generated through the movement of these ions. In addition, electricity is generated as electrons transferred to the anode electrode (100) move to the cathode electrode (200).

[0129] Figures 17 and 18 are drawings showing the combined state (left) of the electrolysis device (60) illustrated in Figure 16 and the state (right) in which an anion exchange membrane (400), a cation exchange membrane (500), an osmotic membrane (700), and a gasket (800) are laminated in multiple stages. The gasket in Figure 17 is a closed type, and the gasket in Figure 18 is an open type.

[0130] Closed gaskets are suitable for manufacturing unit stacks, while open gaskets are suitable for modularizing multiple stacks.

[0131] Experimental example

[0132] 1. Device manufacturing

[0133] A water electrolysis device according to the first embodiment of the present invention was manufactured. Specifically, an anion exchange membrane and a cation exchange membrane with a thickness of 16 μm, independently developed by the Korea Institute of Energy Research, were used for reverse electrodialysis (RED). A 0.5 M NaOH aqueous solution at 20°C was used as the high-concentration solution. 0.0017 M water was used as the low-concentration solution. Ru / Ir on Ti mesh was used as the positive electrode (anode electrode) to be used in the electrode layer, and Pt on Ti mesh was used as the negative electrode (cathode electrode). A 50 mM ferropericyanide solution was used as the electrode solution for reverse electrodialysis.

[0134] For water electrolysis using the anion exchange membrane (AEM) method, i) a water electrolyzer (WE1) using Ni foam as the positive electrode (1) and negative electrode (1) was applied to the right side of the anion exchange membrane for reverse electrodialysis, and ii) a water electrolyzer (WE2) in which Co2Fe2N2on Ni foam of the nitride alloy series was applied to the positive electrode (2) and negative electrode (2) was manufactured. Afterwards, 10 cells were stacked for the reverse electrodialysis / AEM water electrolysis integrated experiment, and low-concentration solutions and high-concentration solutions were supplied to the hybrid stack at 100 mL / min, and the electrode solution was supplied at 50 mL / min.

[0135] Below is a description of the process by condition.

[0136] 1) WE1 - Standalone operation of anion exchange membrane electrolysis using a configuration in which the electrode combination of positive electrode (1) and negative electrode (1) is bonded to the surface of anion exchange membrane

[0137] 2) RED1 - WE1 combined reverse electrodialysis standalone operation

[0138] 3) WE1+RED1 - Simultaneous operation of WE1 and reverse electrodialysis in reverse electrodialysis combined with WE1

[0139] 4) WE2 - Standalone operation of anion exchange membrane electrolysis using a configuration in which the electrode combination of positive electrode (2) and negative electrode (2) is bonded to the surface of anion exchange membrane

[0140] 5) RED2 - WE2 combined reverse electrodialysis standalone operation

[0141] 6) WE2+RED2 - Simultaneous operation of WE2 and reverse electrodialysis in reverse electrodialysis combined with WE2

[0142]

[0143] 2. Energy consumption evaluation

[0144] Figure 19 compares experimental results on energy consumption of a water electrolysis device according to an embodiment of the present invention.

[0145] In the case of WE1, which applied only AEM electrolysis using pure Ni foam with relatively low catalytic activity as a catalyst, the energy consumption for producing 1 kg-H2 was measured to be 65 kWh / kg-H2. On the other hand, in the case of WE1+RED1, which performed the same AEM electrolysis system and reverse electrodialysis simultaneously, the energy consumption was approximately 47 kWh / kg-H2. It was confirmed that energy consumption could be reduced by approximately 18 kWh / kg-H2 by performing combined reverse electrodialysis.

[0146] In the case of WE2, which only applied AEM electrolysis using a catalyst structure in which metal nitride (Co2Fe2N2) nanoparticles with excellent catalytic activity were directly synthesized on the surface of pure Ni foam, the energy consumption for producing 1 kg-H2 was measured to be 42 kWh / kg-H2. This figure is a figure in which energy consumption is reduced by 22 kWh / kg-H2 compared to WE1, and is considered to be due to the effect of increased catalytic activity. In addition, in the case of WE2+RED2, in which AEM electrolysis and reverse electrodialysis were performed simultaneously, the energy consumption was approximately 26 kWh / kg-H2. Through the combined performance of reverse electrodialysis, an additional energy consumption reduction effect of 22 kWh / kg-H2 could be confirmed.

[0147] As a result, it was confirmed that energy consumption can be significantly reduced when electrolysis and reverse electrodialysis are performed simultaneously compared to when electrolysis alone is performed.

[0148] In addition, considering that the energy consumption of a recently reported traditional standalone electrolysis stack is 45-65 kWh / kg-H2, the reverse electrodialysis / AEM electrolysis hybrid process (WE2+RED2) of the present invention was shown to be able to save energy by up to 50% with an energy consumption of 26 kWh / kg-H2.

[0149] From the above description, those skilled in the art will understand that the present invention can be implemented in other specific forms without altering its technical spirit or essential characteristics. In this regard, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention should be interpreted as encompassing all changes or modifications derived from the meaning and scope of the following claims and their equivalent concepts, rather than the detailed description above.

[0150] [Explanation of symbols]

[0151] 10, 20, 30, 40, 50, 60: Water electrolysis device

[0152] 100: Anode electrode

[0153] 200: Cathode electrode

[0154] 300: Ion exchange membrane stack

[0155] 310: 1st Euro

[0156] 320: Second Euro

[0157] 321: 2nd-1st Euro

[0158] 322: 2nd-2nd Euro

[0159] 330: Third Euro

[0160] 400: Anion exchange membrane

[0161] 500: Cation exchange membrane

[0162] 600: Electrode layer

[0163] 700: Osmotic membrane

[0164] 800: Gasket

Claims

1. Cathode electrode and anode electrode facing each other; An ion exchange membrane stack in which anion exchange membranes and cation exchange membranes are alternately arranged so that a first path through which a first solution flows and a second path through which a second solution containing a salt having a higher concentration than the first solution flows are divided into multiple paths, and is arranged between the cathode electrode and the anode electrode; and A water electrolysis device comprising an electrode layer bonded to the surface of the anion exchange membrane or cation exchange membrane.

2. In paragraph 1, A water electrolysis device in which, when the above electrode layer is bonded to the surface of the anion exchange membrane, the cation exchange membrane is positioned closer to each of the cathode electrode and the anode electrode than the anion exchange membrane.

3. In paragraph 1, A water electrolysis device in which, when the electrode layer is bonded to the surface of a cation exchange membrane, an anion exchange membrane is positioned closer to each of the cathode electrode and the anode electrode than the cation exchange membrane.

4. In paragraph 1, At least one gasket is mounted on each end of the cation exchange membrane and the anion exchange membrane, A water electrolysis device, wherein the gaskets are arranged to intersect each other at both ends of the cation exchange membrane and the anion exchange membrane to form a first path through which the first solution flows and a second path through which the second solution flows.

5. Cathode electrode and anode electrode facing each other; An ion exchange membrane stack in which anion exchange membranes, cation exchange membranes, and osmosis membranes are alternately arranged so that a first path through which a first solution flows, a second path through which a second solution containing a higher concentration of salt than the first solution flows, and a third path through which seawater flows are divided into multiple paths, arranged between the cathode electrode and the anode electrode; A water electrolysis device comprising an electrode layer bonded to the surface of the anion exchange membrane or the cation exchange membrane.

6. In paragraph 5, When the above electrode layer is bonded to the surface of the anion exchange membrane, A water electrolysis device, wherein the above-mentioned osmotic membrane is positioned between the anion exchange membrane and the cation exchange membrane, which is positioned adjacent to the anion exchange membrane but is positioned in a direction toward the cathode electrode.

7. In paragraph 5, The third euro is a water electrolysis device formed between the osmotic membrane and the cation exchange membrane adjacent to the osmotic membrane.

8. In paragraph 5, When the above electrode layer is bonded to the surface of the cation exchange membrane, A water electrolysis device, wherein the above-mentioned osmotic membrane is positioned between the above-mentioned cation exchange membrane and the above-mentioned anion exchange membrane positioned adjacent to the above-mentioned cation exchange membrane but in a direction facing the anode electrode.

9. In paragraph 5, The above third euro is a water electrolysis device formed between the above osmotic membrane and the anion exchange membrane adjacent to the above osmotic membrane.

10. In paragraph 5, A water electrolysis device in which an osmotic membrane is arranged between the cation exchange membrane and the anion exchange membrane.

11. In paragraph 5, When the above electrode layer is bonded to the surface of the anion exchange membrane, The third flow path is formed between an osmotic membrane and a cation exchange membrane positioned adjacent to the osmotic membrane but facing the cathode electrode, in a water electrolysis device.

12. In paragraph 5, When the above electrode layer is bonded to the surface of the cation exchange membrane, The third flow path is formed between an osmotic membrane and an anion exchange membrane positioned adjacent to the osmotic membrane but facing the anode electrode.

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