AEM water electrolysis system and AEM water electrolysis system control method

Abstract

The present invention provides an AEM water electrolysis system comprising: an electrolytic cell; a cathode separator provided downstream of the electrolytic cell; a degassing device provided downstream of the cathode separator; and an anode separator provided downstream of the degassing device, wherein hydrogen of a KOH solution discharged from a cathode of the electrolytic cell is degassed through the cathode separator and the degassing device, and the KOH solution is continuously supplied to the electrolytic cell through the anode separator.

Description

AEM water electrolysis system and AEM water electrolysis system control method

[0001] The present invention relates to an Anion Exchange Membrane (AEM) water electrolysis system and a method for controlling the AEM water electrolysis system. More specifically, the present invention relates to an AEM water electrolysis system using a Balance of Plant (BOP) and a method for controlling the AEM water electrolysis system.

[0002] As the need for eco-friendly energy emerges, various forms of energy supply and storage sources are being developed. Hydrogen is the most environmentally friendly energy source from a decarbonization perspective and is gaining attention as an energy carrier and storage medium for new and renewable energies. While there are various methods for producing hydrogen, the most representative method for producing green hydrogen is by electrolyzing water using new and renewable energy.

[0003] A water electrolyzer is a device that produces hydrogen by electrolyzing water, and water electrolyzers can be classified into alkaline, PEM (Polymer Electrolyte Membrane), and AEM depending on the electrolysis membrane. Alkaline electrolyzers use diaphragms instead of membranes; consequently, they have an inherent limitation in that they cannot be directly connected to renewable energy sources due to the high risk of explosion caused by fluctuations in renewable energy. In the case of PEMs, being a membrane type, they are advantageous for load fluctuations, but they require high initial investment costs due to acidic operating conditions and the high cost of iridium (Ir) catalysts. In contrast, AEMs offer the advantage of offsetting both the ability to utilize the variable power of alkaline electrolyzers and the high initial investment costs of PEMs, but they are still a technology in the early stages of development.

[0004] Meanwhile, one of the essential requirements of a water electrolyzer is that it continuously consumes only water to produce hydrogen. If hydrogen is produced using other solvents, it is difficult to have it recognized as green hydrogen. PEMs use only water, whereas alkaline PEMs generally use KOH as a catalyst by initially charging a high concentration of over 33%. AEMs also use KOH, but at a concentration of 0.1M to 2M.

[0005] Since water electrolyzers take the form of green hydrogen using only water, KOH within the system must not be consumed. This problem does not occur with PEMs because they use only water, and it is not an issue with alkaline electrolyzers because they generally share KOH via a both-feeding method using a diaphragm structure. However, in the case of AEMs, while they generally offer advantages in lifespan when KOH is fed to the anode, it is necessary to supply the KOH that passes through the membrane to the cathode back to the anode.

[0006] Typically, KOH is transferred from the cathode separator to the condenser to condense and discharge hydrogen, and then the KOH is circulated back to the cathode separator; however, the KOH recovered from the cathode separator cannot be supplied to the anode and is currently being discarded as is.

[0007] Therefore, there is an urgent need to develop an AEM system that recirculates the KOH flowing into the cathode back to the anode, thereby preventing the continuous charging of KOH into the water electrolysis system.

[0008] Korean Published Patent Application No. 10-2022-0165779 is disclosed as background technology for the present invention.

[0009] The objective of the present invention is to provide an AEM (Anion Exchange Membrane) water electrolysis system that extends the lifespan of the water electrolysis system by supplying KOH to the anode in an AEM water electrolysis system including a BOP (Balance of Plant), and prevents the consumption of KOH by recirculating the KOH that flows into the cathode through the membrane back to the anode.

[0010] Another objective of the present invention is to provide a control method for an AEM water electrolysis system in which, when KOH supplied to the anode in the AEM water electrolysis system flows into the cathode, it is not discarded but continuously circulated to prevent the consumption of KOH within the system.

[0011] The above and other objectives of the present invention can all be achieved by the present invention described below.

[0012] 1. One aspect of the present invention relates to an AEM water electrolysis system.

[0013] The above AEM water electrolysis system is an electrolyzer;

[0014] A cathode separator provided in the downstream of the above electrolytic cell;

[0015] A degassing device provided in the downstream of the above-mentioned cathode separator; and

[0016] Includes an anode separator provided in the downstream of the above degassing device;

[0017] The KOH solution discharged from the cathode of the above electrolytic cell has hydrogen degassed through the cathode separator and degassing device, and is continuously supplied to the above electrolytic cell through the anode separator.

[0018] 2. In the above 1 embodiment, the electrolytic cell may include an anion exchange membrane (AEM), an anode, and a cathode.

[0019] 3. In the above 1 or 2 embodiments, the KOH solution introduced into the anode can pass through the anion exchange membrane and move to the cathode.

[0020] 4. In the above 1 to 3 embodiments, the electrolytic cell can receive electricity from a renewable energy production device.

[0021] 5. In the above 1 to 4 embodiments, the pressure of the cathode may be maintained at about 30 barg or less.

[0022] 6. In the above 1 to 5 embodiments, the cathode separator may be equipped with a level indicator controller connected to a valve provided at the upper and lower portions, respectively.

[0023] 7. In the above 1 to 6 embodiments, the cathode separator is fed with a KOH solution containing dissolved hydrogen and can maintain a maximum water level (HL).

[0024] 8. In the above 1 to 7 embodiments, the cathode separator may be provided with a hydrogen discharge pipe on one side.

[0025] 9. In the above 1 to 8 embodiments, an auto valve may be provided in the downstream of the cathode separator to control the flow of hydrogen and KOH solution.

[0026] 10. In the above 1 to 9 embodiments, a plurality of pressure control valves may be provided in the downstream of the cathode separator to control the pressure of hydrogen flowing into the degassing device.

[0027] 11. In the above 1 to 10 embodiments, a condenser may be further provided on one side of the cathode separator and condense hydrogen and evaporated KOH solution to circulate it to the cathode separator.

[0028] 12. In the above 1 to 11 embodiments, the degassing device may be equipped with a demister at the upper end.

[0029] 13. In the above 1 to 12 embodiments, the degassing device can remove hydrogen remaining in the KOH solution by degassing hydrogen.

[0030] 14. In the above 1 to 13 embodiments, the KOH solution from which hydrogen has been degassed in the degassing device may be supplied to the anode separator.

[0031] 15. In the above 1 to 14 embodiments, the degassing device may be equipped with a level indicator controller connected to a valve provided at the upper and lower portions, respectively.

[0032] 16. In the above 1 to 15 embodiments, the anode separator can continuously supply a hydrogen-degassed KOH solution to the anode of the electrolytic cell.

[0033] 17. Another aspect of the present invention relates to a method for controlling an AEM water electrolysis system using the above-described AEM water electrolysis system.

[0034] The AEM water electrolysis system control method used above is,

[0035] (a) A step of supplying water and KOH to an electrolytic cell and supplying electricity to perform water electrolysis;

[0036] (b) a step of transferring hydrogen discharged from the cathode of the electrolytic cell and the KOH solution introduced from the anode to a cathode separator;

[0037] (c) A step of controlling the maximum water level (HL) of the cathode separator;

[0038] (d) a step of degassing hydrogen in a degassing device provided downstream of the cathode separator;

[0039] (e) supplying the KOH solution from which dissolved hydrogen has been degassed in the above degassing device to an anode separator; and

[0040] (f) a step of continuously supplying a KOH solution from the anode separator to the electrolytic cell;

[0041] 18. In the above 17 embodiment, in step (c), the maximum water level of the cathode separator can be controlled within a range that does not affect the KOH concentration in the anode.

[0042] 19. In the above 17 or 18 embodiments, in step (d), hydrogen remaining in the KOH solution in the degassing device can be degassed and vented to the outside.

[0043] 20. In the above 17 to 19 embodiments, in step (f), the KOH solution of the anode separator can be continuously supplied to the anode of the electrolytic cell.

[0044] The AEM water electrolysis system according to the present invention comprises a Balance of Plant (BOP) including a cathode separator and a degasser, so that even when KOH supplied to the anode passes through a membrane and flows into the cathode, the KOH solution can be recovered from the cathode and continuously supplied to the anode.

[0045] By forming a buffer of the KOH solution in the cathode separator positioned downstream of the cathode to release hydrogen within the KOH solution, the amount of dissolved hydrogen is reduced. Subsequently, the hydrogen released from the degassing device is discharged externally, allowing the pressure-controlled KOH solution to be continuously supplied to the anode. This extends the lifespan of the water electrolysis system and very effectively prevents the consumption of KOH in the AEM water electrolysis system.

[0046] FIG. 1 is a process flow diagram of an AEM water electrolysis system according to one embodiment of the present invention.

[0047] FIG. 2 is a process flow diagram of an AEM water electrolysis system according to another embodiment of the present invention.

[0048] FIG. 3 is a process flowchart of an AEM water electrolysis system control method according to one embodiment of the present invention.

[0049] The present invention will be described in more detail below with reference to the attached drawings. However, the following drawings are provided merely to aid in understanding the present invention, and the present invention is not limited by the drawings. Furthermore, the shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings are exemplary, and the present invention is not limited to the depicted details.

[0050] Throughout the specification, the same reference numerals refer to the same components. Additionally, in describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the invention.

[0051] Where terms such as 'includes,' 'have,' and 'consists of' are used in this specification, other parts may be added unless 'only' is used. Where a component is expressed in the singular, it includes cases where it is in the plural unless specifically stated otherwise.

[0052] In interpreting the components, they are interpreted to include a margin of error even in the absence of a separate explicit statement.

[0053] In this specification, "a to b" indicating a numerical range is defined as "≥a and ≤b".

[0054] In this specification, all numerical ranges include a 95% standard error range.

[0055] One aspect of the present invention relates to an AEM water electrolysis system (1000).

[0056] FIG. 1 is a process flow diagram of an AEM water electrolysis system according to one embodiment of the present invention, and FIG. 2 is a process flow diagram of an AEM water electrolysis system according to another embodiment of the present invention.

[0057] Referring to FIG. 1, the AEM water electrolysis system (1000) includes an electrolytic cell (100), a cathode separator (200), a degassing device (400), and an anode separator (500).

[0058] The above electrolytic cell (100) may be equipped with a plurality of electrolytic cells (130) equipped with an anion exchange membrane (AEM), an anode (110), and a cathode (120).

[0059] The above anion exchange membrane is advantageous for power load changes, just like the polymer electrolyte membrane (PEM), and is very economical because it does not require precious metal catalysts such as platinum or iridium since it is not operated under strong acidic conditions.

[0060] When the above electrolytic cell (100) includes an anion exchange membrane, it has the advantage of being able to perform water electrolysis with low power and operate at high pressure, resulting in high efficiency and high purity of hydrogen produced.

[0061] In the above cathode (120), a reaction according to the following chemical formula 1 may occur.

[0062] [Chemical Formula 1]

[0063] 2H2O + 2e - → H2 + 2OH -

[0064] In the above anode (110), a reaction according to the following chemical formula 2 may occur.

[0065] [Chemical Formula 2]

[0066] 2OH - → 1 / 2O2 + H2O + 2e -

[0067] According to the above chemical formula 1, water is reduced at the cathode (120) to generate hydrogen, and hydroxide ions (OH) that have passed through the anion exchange membrane - ) can be oxidized at the anode (110) to release oxygen and water.

[0068] When a KOH solution is introduced into the anode (110), it can pass through the anion exchange membrane and move to the cathode (120).

[0069] Specifically, KOH present in the anode (110) of the electrolytic cell (100) can move to the cathode (120), and the KOH solution introduced into the anode (110) passes through the anion exchange membrane and moves to the cathode (120), so that the KOH present in the anode (110) can be continuously consumed.

[0070] If the above KOH is not present in the anode (110), there is a problem that the water electrolysis efficiency is greatly reduced, and if the KOH solution passes through the anion exchange membrane and moves to the cathode (120), there is a need to supply the consumed KOH back to the anode (110).

[0071] The water (H2O) generated at the anode (110) can be recovered to the anode separator (500) along the water discharge line (S11).

[0072] The above electrolytic cell (100) can receive electricity from a renewable energy production device (10).

[0073] The above electrolytic cell (100) receives electricity from a renewable energy production device (10), and when the cathode (120) and anode (110) are connected to each other, it performs a water electrolysis reaction according to the above chemical formulas 1 and 2. For example, it can perform water electrolysis by receiving electricity from a renewable energy production device such as a solar cell, wind power, tidal power, or hydropower.

[0074] If the above electrolytic cell (100) includes an anion exchange membrane, water electrolysis is possible even when there are large fluctuations in electrical load, such as in a renewable energy production device.

[0075] The pressure of the cathode (120) can be maintained at about 30 barg or less. For example, it can be greater than about 0 barg and less than or equal to 30 barg (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30).

[0076] The pressure of the cathode (120) of the electrolytic cell (100) can be maintained within the above range, and if it deviates from the above range, the KOH solution flowing into the cathode (120) is circulated directly to the anode (110), and a large amount of KOH solution flows into the anode (110), making it difficult to retain KOH at a certain concentration in the anode (110).

[0077] Because there is a problem with hydrogen leakage during the process of the above KOH solution being introduced, it is necessary to regulate the amount of KOH introduced into the anode (110) from the downstream side of the cathode (120) and to vent the hydrogen in advance.

[0078] The above cathode separator (200) is provided after the above electrolytic cell (100).

[0079] The cathode separator (200) above provides a buffer for the KOH solution discharged from the cathode (120), and the KOH solution can be introduced and stored at a constant level.

[0080] The above cathode separator (200) can function as a gas-liquid separator that separates hydrogen and KOH solution discharged from the electrolytic cell.

[0081] The KOH solution discharged from the cathode (120) of the electrolytic cell (100) can be introduced into the cathode separator (200) along the connecting line (S2).

[0082] The above cathode separator (200) is provided to control the flow rate of the KOH solution flowing into the anode (110) of the electrolytic cell (100) and to control the concentration of the KOH solution remaining in the anode (110).

[0083] The above cathode separator (200) may be equipped with a level indicator controller (210) connected to valves (not shown) provided at the upper and lower ends, respectively.

[0084] A valve capable of measuring the level of the KOH solution inside the cathode separator (200) is provided at the upper and lower portions of the cathode separator (200), and the valve is linked with a level indication controller (hereinafter 'LIC') to accurately measure and display the level of the KOH solution inside the cathode separator (200).

[0085] The above cathode separator (200) is fed with a KOH solution containing dissolved hydrogen and can maintain a maximum water level (HL).

[0086] The above LIC (210) can measure the level of the KOH solution in the cathode (120) and can check whether the maximum level of the KOH solution is maintained during the operation of the electrolytic cell (100).

[0087] The above High Level (HL) is a level at which the concentration of the KOH solution circulated through the cathode separator (200) can be maintained at a constant level so as not to affect the concentration of the KOH solution present in the anode (110).

[0088] If the above maximum level is adjusted too low, there is a problem where a large amount of hydrogen is contained in the KOH solution and discharged, and if it is adjusted too high, gas-liquid separation does not occur smoothly.

[0089] In one embodiment, the KOH solution is circulated so that the KOH present in the anode (110) is not consumed, and the level of the KOH solution in the cathode separator (200) at the moment the KOH is circulated through the cathode separator (200) can be determined as the highest level (HL).

[0090] The above LIC (210) is provided to accurately measure and display the level of the KOH solution in the cathode separator (200).

[0091] The above cathode separator (200) may be equipped with a hydrogen discharge line (S12) on one side.

[0092] The above hydrogen discharge line (S12) can prevent the hydrogen discharged from the cathode separator from exploding due to the pressure being higher than the design pressure, and specifically, a pressure safety valve (220) is provided to regulate the pressure.

[0093] An auto valve (240) that controls the flow of hydrogen and KOH solution may be provided downstream of the cathode separator (200).

[0094] The above auto valve (240) can control the flow rate of the KOH solution discharged from the cathode separator (200) and can be opened and closed to maintain a constant maximum water level by comparing the water level measured at the LIC with a predetermined maximum water level.

[0095] A control panel (230) may be provided on one side of the auto valve (240), and the control panel (230) is electrically connected to the LIC and, specifically, is provided with a Displayed Programmable Indicator, and the control panel (230) and the LIC (210) are connected to the Displayed Programmable Indicator so that the opening and closing of the auto valve is determined according to the level of the KOH solution measured at the LIC (210), thereby allowing the maximum water level inside the cathode separator (200) to be maintained at a constant level.

[0096] A condenser (300) may be provided on one side of the cathode separator (200) to condense hydrogen and evaporated KOH solution and circulate it to the cathode separator (200).

[0097] The above condenser (300) is provided so that hydrogen and evaporated KOH solution present in the cathode separator (200) flow into the condenser (300) along the discharge line (S3), and the heat exchange is condensed so that the KOH solution is recovered to the cathode separator (200) along the inflow line (S4), thereby preventing the consumption of KOH.

[0098] A plurality of pressure control valves (250) may be provided in the downstream of the cathode separator (200) to control the pressure of hydrogen flowing into the degassing device (400).

[0099] The pressure control valve (250) above may be a double block and bleed valve (DDB).

[0100] The flow rate of the KOH solution is controlled at the auto valve (240) provided in the KOH discharge line (S5) connected to the downstream of the cathode separator (200), and the KOH solution can move to the pressure control valve along the auto valve line (S6).

[0101] When hydrogen is mixed in the above KOH solution and the amount of hydrogen in the above degassing device (400) increases so that degassing in the KOH solution is not completely achieved, some hydrogen can be discharged in advance by opening and closing the above pressure control valve (250). For example, when the second double block valve (251) and the bleed valve (252) are opened and the first double block valve (253) is closed, hydrogen in the KOH solution flowing along the auto valve line (S6) can be discharged in advance to control the hydrogen flow rate in the above degassing device (400).

[0102] The above degassing device (400) is provided after the cathode separator (200).

[0103] The above degassing device (400) can receive hydrogen and KOH solution, vent hydrogen, and store KOH solution.

[0104] Specifically, the above degassing device (400) may be equipped with a demister at the top. By being equipped with the demister, only pure hydrogen can be discharged and the KOH solution can be collected, and the pressure of the KOH solution can be lowered so that the high-pressure KOH solution does not flow into the anode separator (500).

[0105] The above degreasing device (400) recovers the KOH solution and can prevent hydrogen from being introduced along with it when supplied to the anode separator (500).

[0106] The above degassing device (400) is operated under atmospheric pressure conditions and can degas hydrogen to discharge hydrogen remaining in the KOH solution.

[0107] Hydrogen can be degassed in the above degassing device (400) and discharged to the outside through the second hydrogen discharge line (S8). It is also possible for the second hydrogen discharge line (S8) to join the first hydrogen discharge line (S12) to collect and store high-purity hydrogen or supply it to the outside.

[0108] The KOH solution from which hydrogen has been degassed in the above degassing device (400) can be supplied to the above anode separator (500).

[0109] The above degassing device (400) may be equipped with a level indicator controller (not shown) connected to a valve provided at the upper and lower ends, respectively.

[0110] The above degassing device (400) is equipped with an LIC and can control the level of the KOH solution stored in the degassing device (400) and determine the flow rate of the KOH solution supplied to the anode separator (500).

[0111] The above LIC is provided so that the maximum water level (HL) of the KOH solution within the above degassing device (400) can be determined, and the maximum water level can be controlled to maintain a constant KOH concentration within the anode (110), just like the maximum water level of the above cathode separator (200).

[0112] The above anode separator (500) is provided downstream of the above degassing device (400).

[0113] The KOH solution can be transferred to an anode separator (500) along a KOH transfer line (S9) provided downstream of the above degassing device (400).

[0114] The above anode separator (500) can continuously supply a hydrogen-degassed KOH solution to the anode (110) of the electrolytic cell (100).

[0115] The above anode separator (500) supplies a hydrogen-degassed KOH solution to the anode (110) to maintain a constant KOH concentration within the anode (110), thereby increasing water electrolysis efficiency and preventing KOH consumption.

[0116] The KOH discharged from the cathode (120) of the electrolytic cell (100) has hydrogen degassed through the cathode separator (200) and degasser (400), and is continuously supplied to the electrolytic cell (100) through the anode separator (500).

[0117] The above cathode separator (200) determines the flow rate of the KOH solution delivered to the anode (110) and can increase the purity of the KOH solution introduced into the anode (110) by degassing hydrogen that is introduced along with the KOH solution from the degassing device (400) or dissolved in the solution, and can ensure that a certain amount of KOH exists within the anode (110).

[0118] Referring to FIG. 2, the cathode separator (300) and anode separator (500) may be vertical, and may be selected from horizontal or vertical types as long as they can form a buffer of KOH solution to separate hydrogen, and are not particularly limited.

[0119] Accordingly, the AEM water electrolysis system (1000) according to one aspect of the present invention forms a Balance of Plant (BOP), and by controlling the flow rate of the KOH solution in the cathode separator (200) to maintain a constant concentration of KOH present in the anode (110) and discharging hydrogen through the degassing device (400), the KOH that has moved to the conventional cathode (120) is not discarded but is continuously supplied to the electrolytic cell (100), thereby greatly improving the efficiency of the AEM water electrolysis system (1000) and enabling commercial operation of the AEM water electrolysis system (1000).

[0120]

[0121] Another aspect of the present invention relates to a method for controlling an AEM water electrolysis system using the above-described AEM water electrolysis system.

[0122] FIG. 3 is a process flowchart of an AEM water electrolysis system control method according to one embodiment of the present invention.

[0123] Referring to FIG. 3, the control method for the AEM water electrolysis system used above comprises: (a) a step of supplying water and KOH to an electrolytic cell and supplying electricity to perform water electrolysis;

[0124] (b) a step of transferring hydrogen discharged from the cathode of the electrolytic cell and the KOH solution introduced from the anode to a cathode separator;

[0125] (c) A step of controlling the maximum water level (HL) of the cathode separator;

[0126] (d) a step of degassing hydrogen in a degassing device provided downstream of the cathode separator;

[0127] (e) supplying the KOH solution from which dissolved hydrogen has been degassed in the above degassing device to an anode separator; and

[0128] (f) a step of continuously supplying a KOH solution from the anode separator to the electrolytic cell;

[0129] First, water and KOH are supplied to the electrolytic cell, and electricity is supplied to perform water electrolysis (S100).

[0130] The above electricity may be introduced from a renewable energy production device, and since the electrolytic cell includes an anion exchange membrane, it can respond to fluctuations in the electrical load, so hydrogen can be effectively produced as an energy storage source using renewable energy.

[0131] Hydrogen discharged from the cathode of the above electrolytic cell and KOH solution introduced from the anode are transferred to a cathode separator (S200).

[0132] Hydrogen is generated by the water electrolysis reaction in the above electrolytic cell, and the KOH from the anode can pass through the anion exchange membrane to reach the cathode, and when discharged from the cathode, KOH must be replenished to the anode.

[0133] The above KOH solution can be transferred to a cathode separator to form a buffer of the KOH solution and control the flow rate.

[0134] The maximum water level (HL) of the above cathode separator is adjusted (S300).

[0135] In the above S300, the maximum water level (HL) of the cathode separator can be controlled within a range that does not affect the KOH concentration in the anode, and specifically, the maximum water level of the KOH solution can be controlled using the LIC and the subsequent auto valve provided in the cathode separator within a range that can maintain the concentration of KOH present in the anode constant.

[0136] Hydrogen is degassed in a degasification device provided after the cathode separator (S400).

[0137] Through the above degassing device, the pressure of the KOH solution can be controlled, and at the same time, hydrogen contained in the KOH solution discharged from the downstream of the cathode separator can be degassed.

[0138] In the above S400, hydrogen remaining in the KOH solution can be degassed and vented to the outside.

[0139] The above-mentioned degassed hydrogen can be combined with the hydrogen discharged from the cathode separator, captured and stored, or supplied externally.

[0140] The KOH solution from which dissolved hydrogen has been removed in the above degassing device is supplied to the anode separator (S500).

[0141] The above KOH solution is degassed to be free of hydrogen and can be transferred to an anode separator for storage.

[0142] The KOH solution from the above anode separator is continuously supplied to the anode of the electrolytic cell (S600)

[0143] In the above S600, the KOH solution of the anode separator can be continuously supplied to the anode of the electrolytic cell.

[0144] The above anode separator can control the flow rate of the KOH solution supplied to the anode, and the anode separator can continuously supply the KOH solution to maintain a constant KOH concentration within the anode.

[0145] Accordingly, the AEM water electrolysis system control method according to another aspect of the present invention can improve the efficiency of the AEM water electrolysis system and enable the scale-up and commercialization of the water electrolysis system because it can continuously supply the KOH solution directly to the anode by using the AEM water electrolysis system to capture the KOH solution flowing into the cathode through an anion exchange membrane, which is a membrane, and circulating it within the BOP at a constant flow rate, and by discharging hydrogen through a degassing device to lower the pressure.

[0146]

[0147] The present invention has been described above with reference to embodiments. Those skilled in the art will understand that the present invention may be implemented in modified forms without departing from the essential characteristics of the invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the invention is defined by the claims, not by the foregoing description, and all variations within the scope of equivalents should be interpreted as being included in the invention.

Claims

1. Electrolyzer; A cathode separator provided in the downstream of the above electrolytic cell; A degassing device provided in the downstream of the above-mentioned cathode separator; and It includes an anode separator provided in the downstream of the above-mentioned degassing device; and The KOH solution discharged from the cathode of the electrolytic cell is degassed of hydrogen through the cathode separator and the degassing device, and is continuously supplied to the electrolytic cell through the anode separator. AEM Water Electrolysis System.

2. In claim 1, the electrolytic cell comprises an anion exchange membrane (AEM), an anode, and a cathode, forming an AEM water electrolysis system.

3. An AEM water electrolysis system according to paragraph 2, wherein the KOH solution introduced into the anode passes through the anion exchange membrane and moves to the cathode.

4. An AEM water electrolysis system according to claim 1, wherein the electrolytic cell receives electricity from a renewable energy production device.

5. An AEM water electrolysis system according to paragraph 2, wherein the pressure of the cathode is maintained at about 30 barg or less.

6. An AEM water electrolysis system according to claim 1, wherein the cathode separator is equipped with a level indicator controller connected to a valve provided at the upper and lower ends, respectively.

7. An AEM water electrolysis system according to claim 6, wherein the cathode separator receives a KOH solution containing dissolved hydrogen and maintains a maximum water level (HL).

8. An AEM water electrolysis system according to claim 1, wherein the cathode separator is equipped with a hydrogen discharge pipe on one side.

9. An AEM water electrolysis system according to claim 1, wherein the system is provided with an auto valve that controls the flow of hydrogen and KOH solution, and is provided downstream of the cathode separator.

10. An AEM water electrolysis system according to claim 1, wherein a plurality of pressure control valves are provided in the downstream of the cathode separator and regulate the pressure of hydrogen flowing into the degassing device.

11. An AEM water electrolysis system according to claim 1, further comprising a condenser provided on one side of the cathode separator, which condenses hydrogen and evaporated KOH solution and circulates it to the cathode separator.

12. An AEM water electrolysis system according to claim 1, wherein the degassing device is equipped with a demister at the upper end.

13. An AEM water electrolysis system according to claim 1, wherein the degassing device degass hydrogen to remove hydrogen remaining in the KOH solution.

14. An AEM water electrolysis system according to claim 1, wherein the KOH solution from which hydrogen has been degassed in the degasser is supplied to the anode separator.

15. An AEM water electrolysis system according to claim 1, wherein the degassing device is equipped with a level indicator controller connected to valves provided at the upper and lower ends, respectively.

16. An AEM water electrolysis system according to claim 1, wherein the anode separator continuously supplies a hydrogen-degassed KOH solution to the anode of the electrolytic cell. 17.(a) A step of supplying water and KOH to an electrolytic cell and supplying electricity to perform water electrolysis; (b) a step of transferring hydrogen discharged from the cathode of the electrolytic cell and the KOH solution introduced from the anode to a cathode separator; (c) A step of controlling the maximum water level (HL) of the cathode separator; (d) a step of degassing hydrogen in a degassing device provided downstream of the cathode separator; (e) supplying the KOH solution from which dissolved hydrogen has been degassed in the above degassing device to an anode separator; and (f) a step of continuously supplying a KOH solution from the anode separator to the electrolytic cell; comprising, Control method of AEM water electrolysis system.

18. A method for controlling an AEM water electrolysis system, wherein, in step (c) of claim 17, the maximum water level of the cathode separator is controlled within a range that does not affect the KOH concentration in the anode.

19. A control method for an AEM water electrolysis system according to claim 17, wherein in step (d) above, hydrogen remaining in the KOH solution in the degassing device is degassed and vented to the outside.

20. A control method for an AEM water electrolysis system according to claim 17, wherein in step (f) above, the KOH solution of the anode separator is continuously supplied to the anode side of the electrolytic cell.

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