Hydrogen production system by water electrolysis

Abstract

This application discloses a water electrolysis hydrogen production system, relating to the field of hydrogen production technology. The system includes an electrolyzer and separators. Each electrolysis product flow path is equipped with a first separator, and at least in the first electrolysis product flow path, a second separator is located downstream of the first separator. One separator in the first electrolysis product flow path is connected to one separator in the second electrolysis product flow path via a liquid-conducting pipe. The first and second separators in the same electrolysis product flow path are connected via a liquid-conducting pipe and a gas-conducting pipe. The electrolysis products from the first separator flow to the second separator via the gas-conducting pipe. The outlet of the gas-conducting pipe and the top and bottom walls of the second separator are spaced apart. The system also includes a level regulating device for adjusting the level of the first separator in the second electrolysis product flow path. This application's technical solution improves the operational stability of the water electrolysis hydrogen production system.

Description

Technical Field

[0001] This application relates to the field of hydrogen production technology, and in particular to a water electrolysis hydrogen production system. Background Technology

[0002] In existing water electrolysis hydrogen production processes, frequent fluctuations in the operating power of the water electrolysis hydrogen production system can easily cause imbalances in the liquid levels of the hydrogen separator and oxygen separator, leading to a decrease in gas purity and even the possibility of cross-contamination between hydrogen and oxygen, posing potential safety risks. Utility Model Content

[0003] The main objective of this application is to propose a water electrolysis hydrogen production system, which aims to improve the operational stability of the water electrolysis hydrogen production system.

[0004] To achieve the above objectives, the water electrolysis hydrogen production system proposed in this application includes an electrolyzer and a separator, wherein the electrolyzer is connected to two electrolysis product flow paths, and the separator is provided in each electrolysis product flow path;

[0005] The electrolytic cell is connected to two electrolytic product flow paths, namely a first electrolytic product flow path and a second electrolytic product flow path. Each electrolytic product flow path is provided with a first separator. At least in the first electrolytic product flow path, a second separator is provided downstream of the first separator.

[0006] The separator includes a first separator and a second separator, and one of the separators in the first electrolysis product flow path is connected to one of the separators in the second electrolysis product flow path through a liquid guiding pipe.

[0007] The first separator and the second separator in the same electrolysis product flow path are connected by a liquid-conducting pipe and a gas-conducting pipe. The electrolysis product of the first separator flows to the second separator through the gas-conducting pipe. The outlet of the gas-conducting pipe and the top and bottom walls of the second separator are spaced apart.

[0008] The water electrolysis hydrogen production system includes a liquid level regulating device, which is used to regulate the liquid level of the first separator in the second electrolysis product flow path.

[0009] In one embodiment, the number of the second separators is one, wherein one of the electrolysis product flow paths is a hydrogen-side electrolysis product flow path, and the hydrogen-side electrolysis product flow path is provided with a liquid level difference regulating valve;

[0010] Each of the two first separators is equipped with a liquid level sensor, and the liquid level difference regulating valve is electrically connected to the two liquid level sensors to serve as the liquid level regulating device.

[0011] In one embodiment, the water electrolysis hydrogen production system further includes a return liquid flow path, the outlet end of which is connected to the electrolytic cell, and the return liquid flow path includes two return liquid branches, the inlet ends of which are respectively connected to different separators.

[0012] In one embodiment, the inlet end of one of the return liquid branches is connected to the second separator.

[0013] In one embodiment, the second separator is provided in both electrolysis product flow paths, and the second separator in the second electrolysis product flow path and the gas guiding pipe connected thereto serve as the liquid level regulating device.

[0014] In one embodiment, the two second separators are connected by a liquid-conducting connecting pipe.

[0015] In one embodiment, the water electrolysis hydrogen production system further includes a return liquid flow path, the outlet end of which is connected to the electrolytic cell, and the return liquid flow path includes two return liquid branches, the inlet ends of which are respectively connected to two second separators.

[0016] In one embodiment, the gas guide tube is inserted at the top of the second separator.

[0017] In one embodiment, the ratio of the distance between the outlet of the air-conducting pipe and the bottom wall of the second separator to the height of the second separator is K, where 0.2 ≤ K ≤ 0.6.

[0018] In one embodiment, one of the electrolysis product flow paths is an oxygen-side electrolysis product flow path, the oxygen-side electrolysis product flow path is provided with a pressure regulating valve, the first separator or the second separator of the oxygen-side electrolysis product flow path is provided with a pressure sensor, and the pressure regulating valve is electrically connected to the pressure sensor.

[0019] The technical solution of this application connects a first separator and a second separator in the same electrolysis product flow path through a liquid-conducting pipe and a gas-conducting pipe. The outlet of the gas-conducting pipe and the top and bottom walls of the second separator are spaced apart, allowing the outlet of the gas-conducting pipe to extend below the electrolyte surface of the second separator. This ensures that the liquid level of the first separator in the first electrolysis product flow path is constant and does not change with fluctuations in hydrogen production power. Simultaneously, by connecting one separator in the first electrolysis product flow path to one separator in the second electrolysis product flow path through a liquid-conducting pipe and installing a liquid level regulating device to adjust the liquid level of the first separator in the second electrolysis product flow path, the liquid levels of the first separators in both electrolysis product flow paths are the same. This achieves a balance between the liquid levels of the first separators in both electrolysis product flow paths, ensuring that their levels do not change with fluctuations in hydrogen production power. This improves the stability and reliability of the hydrogen production system and better adapts to hydrogen production from renewable energy sources. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 A schematic diagram of a water electrolysis hydrogen production system according to an embodiment of the present application;

[0022] Figure 2 A schematic diagram of another embodiment of the water electrolysis hydrogen production system provided in this application;

[0023] Figure 3 A schematic diagram illustrating the liquid level balance of an embodiment of the water electrolysis hydrogen production system provided in this application;

[0024] Figure 4 A schematic diagram of the liquid level balance in another embodiment of the water electrolysis hydrogen production system provided in this application;

[0025] Figure 5 A schematic diagram of another embodiment of the water electrolysis hydrogen production system provided in this application;

[0026] Figure 6 A schematic diagram of another embodiment of the water electrolysis hydrogen production system provided in this application;

[0027] Figure 7 This is a schematic diagram of another embodiment of the water electrolysis hydrogen production system provided in this application.

[0028] Explanation of icon numbers:

[0029] 100. Electrolytic cell; 200. First separator; 210. Oxygen-side first separator; 220. Hydrogen-side first separator; 300. Second separator; 310. Oxygen-side second separator; 320. Hydrogen-side second separator; 410. Liquid level differential regulating valve; 420. Liquid level sensor; 510. Pressure regulating valve; 520. Pressure sensor; 610. First electrolysis product flow path; 620. Second electrolysis product flow path; 630. Return liquid flow path; 710. Liquid guiding connecting pipe; 720. Gas guiding connecting pipe.

[0030] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0032] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0033] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0034] This application proposes a water electrolysis hydrogen production system.

[0035] Please see Figure 1In one embodiment of this application, the water electrolysis hydrogen production system includes an electrolyzer 100 and a separator. The electrolyzer 100 is connected to two electrolysis product flow paths, and each electrolysis product flow path is equipped with a separator. The two electrolysis product flow paths are a first electrolysis product flow path 610 and a second electrolysis product flow path 620. Each electrolysis product flow path is equipped with a first separator 200. At least in the first electrolysis product flow path 610, a second separator 300 is provided downstream of the first separator 200. The separator includes a first separator 200 and a second separator 300. One of the separators in the first electrolysis product flow path 610... The device is connected to one of the separators in the second electrolysis product flow path 620 via a liquid-conducting connecting pipe 710; the first separator 200 and the second separator 300 in the same electrolysis product flow path are connected via a liquid-conducting connecting pipe and a gas-conducting connecting pipe 720. The electrolysis products of the first separator 200 flow to the second separator 300 via the gas-conducting connecting pipe 720. The outlet of the gas-conducting connecting pipe 720 and the top and bottom walls of the second separator 300 are spaced apart; the water electrolysis hydrogen production system includes a liquid level regulating device, which is used to regulate the liquid level of the first separator 200 in the second electrolysis product flow path 620.

[0036] Specifically, the electrolyzer 100 of the water electrolysis hydrogen production system can decompose water into hydrogen and oxygen. The gas generated on the electrode surface corresponding to the electrolyzer 100 carries a small amount of electrolyte. The electrolysis product exiting the electrolysis product outlet of the electrolyzer 100 is a gas-liquid mixture. The flow path of the gas-liquid mixture between the electrolysis product outlet of the electrolyzer 100 and the gas outlet of the water electrolysis hydrogen production system, through which it undergoes gas-liquid separation, washing and cooling, and gas-water separation, is the electrolysis product flow path of the water electrolysis hydrogen production system. The first separator 200 is connected to the electrolyzer 100 and is used to initially separate the electrolyte in the gas-liquid mixture. After the initial separation in the first separator 200, the liquid phase of the gas-liquid mixture remains in the first separator 200, while the gas phase is vented or enters the downstream purification process after washing, cooling, and gas-water separation.

[0037] Please see Figure 1 The first electrolysis product flow path 610 can be connected to the oxygen-side electrolysis product outlet of the electrolytic cell 100. The first separator 200 on the first electrolysis product flow path 610 is used for preliminary separation of the electrolyte in the gas-liquid mixture. At this time, the electrolyte remaining in the first separator 200 contains a small amount of oxygen. The second electrolysis product flow path 620 can be connected to the hydrogen-side electrolysis product outlet of the electrolytic cell 100. The first separator 200 on the second electrolysis product flow path 620 is used for preliminary separation of the electrolyte in the gas-liquid mixture. At this time, the electrolyte remaining in the first separator 200 contains a small amount of hydrogen. Conversely, please refer to [the original text is missing here, so the translation ends here]. Figure 2Alternatively, the first electrolysis product flow path 610 can be connected to the hydrogen-side electrolysis product outlet of the electrolytic cell 100, and the second electrolysis product flow path 620 can be connected to the oxygen-side electrolysis product outlet of the electrolytic cell 100. No restrictions are imposed here.

[0038] One of the separators in the first electrolysis product flow path 610 is connected to one of the separators in the second electrolysis product flow path 620 via a liquid guiding pipe 710. When only the first electrolysis product flow path 610 is equipped with the second separator 300, please refer to [the relevant documentation]. Figure 3 The second separator 300 of the first electrolysis product flow path 610 and the first separator 200 of the second electrolysis product flow path 620 can be connected by a liquid-conducting connecting pipe 710, allowing the electrolyte to flow between them; please refer to Figure 4 Alternatively, the first separators 200 of the two electrolysis product flow paths can be connected by a liquid-conducting connecting pipe 710, allowing the electrolyte to flow between them. In this way, the electrolyte in the first separators 200 of both electrolysis product flow paths can flow into the second separator 300 through the liquid-conducting connecting pipe 710, and the electrolyte in the second separator 300 can also flow into the two first separators 200 through the liquid-conducting connecting pipe 710. When both the first electrolysis product flow path 610 and the second electrolysis product flow path 620 are equipped with a second separator 300, please refer to [reference needed]. Figure 5 Alternatively, the second separator 300 of the first electrolysis product flow path 610 and the second separator 300 of the second electrolysis product flow path 620 can be connected through a liquid guiding pipe 710. In this way, the electrolyte can not only flow between the first separator 200 and the second separator 300 in the same electrolysis product flow path, but also between the second separators 300 in the two electrolysis product flow paths.

[0039] Please see Figure 1 and Figure 3 The first separator 200 and the second separator 300, which share the same electrolysis product flow path, are connected by a liquid-conducting connecting pipe 710 and a gas-conducting connecting pipe 720. The electrolysis products (gas carrying a small amount of electrolyte after preliminary separation) in the first separator 200 are introduced into the second separator 300, which shares the same electrolysis product flow path, through the gas-conducting connecting pipe 720. The first separator 200 and the second separator 300 are connected by the liquid-conducting connecting pipe 710, allowing the electrolyte to flow between them. The outlet of the gas-conducting connecting pipe 720 and the top and bottom walls of the second separator 300 are spaced apart, so that the outlet of the gas-conducting connecting pipe 720 is below the electrolyte surface in the second separator 300.

[0040] In the first electrolysis product flow path 610, the gas phase pressures of the second separator 300 and the first separator 200 are P2 and P3 respectively, and their liquid level heights are H2 and H3 respectively. The real-time distance from the outlet of the gas-conducting pipe 720 to the liquid surface of the second separator 300 is H0 (H0 varies with the liquid level H2). Therefore, the distance between the inlet of the gas-conducting pipe 720 and the inner bottom wall of the second separator 300 is (H2-H0), where (H2-H0) is a constant. Since the separators are connected by the liquid-conducting pipe 710, according to Bernoulli's equation:

[0041] P2 + ρgH2 = P3 + ρgH3;

[0042] P3 = P2 + ρgH0;

[0043] From the above two equations, we can see that:

[0044] P2+ρgH2=P2+ρgH0+ρgH3;

[0045] Then H2 = H0 + H3;

[0046] That is, H3 = H2 - H0, so H3 is also a constant (the size of H3 needs to be designed based on the relative sizes of H2 and H0).

[0047] Of course, when the second electrolysis product flow path 620 is equipped with a second separator 300, the liquid level of the first separator 200 in the second electrolysis product flow path 620 is also a constant value. This will not be elaborated further here.

[0048] In this way, by connecting the gas and liquid phases of the first separator 200 and the second separator 300 in the same electrolysis product flow path, the liquid level of the first separator 200 in the electrolysis product flow path can be reliably controlled to a constant value, preventing it from changing with fluctuations in hydrogen production power. Simultaneously, by adjusting the liquid level of the first separator 200 in the other electrolysis product flow path using a liquid level regulating device, the liquid levels of the first separators 200 in both electrolysis product flow paths are made the same, i.e., the liquid levels of the two first separators 200 are constant. This achieves a balance between the liquid levels of the two first separators 200, ensuring that their liquid levels do not change with fluctuations in hydrogen production power, thereby improving the stability and reliability of the hydrogen production system.

[0049] Especially when the hydrogen production system is coupled with renewable energy for hydrogen production, the operating power of the hydrogen production system will fluctuate frequently. The liquid levels of the two first separators 200 of the hydrogen production system proposed in this application do not change with the fluctuation of hydrogen production power. The hydrogen production system has good stability and reliability during operation and can better adapt to hydrogen production from renewable energy.

[0050] The technical solution of this application connects the first separator 200 and the second separator 300 in the same electrolysis product flow path through a liquid-conducting pipe 710 and a gas-conducting pipe 720. The outlet of the gas-conducting pipe 720 and the top and bottom walls of the second separator 300 are spaced apart, allowing the outlet of the gas-conducting pipe 720 to extend below the electrolyte surface of the second separator 300. This ensures that the liquid level of the first separator 200 in the first electrolysis product flow path 610 remains constant and does not change with fluctuations in hydrogen production power. Simultaneously, through the first electrolysis product flow path 61... One of the separators in the first separator 200 of the second electrolysis product flow path 620 is connected to one of the separators in the second electrolysis product flow path 620 via a liquid guiding pipe 710. A liquid level regulating device is provided to regulate the liquid level of the first separator 200 in the second electrolysis product flow path 620, so that the liquid levels of the first separator 200 in the two electrolysis product flow paths are the same. Thus, the liquid levels of the first separator 200 in the two electrolysis product flow paths reach equilibrium, and their liquid levels do not change with the fluctuation of hydrogen production power. This improves the stability and reliability of the hydrogen production system and enables it to better adapt to hydrogen production from renewable energy sources.

[0051] Furthermore, the gas entering the first electrolysis product flow path 610 is a first gas, and the gas entering the second electrolysis product flow path 620 is a second gas. When the first electrolysis product flow path 610 is connected to the oxygen-side electrolysis product outlet of the electrolytic cell 100, the first gas is oxygen and the second gas is hydrogen; when the first electrolysis product flow path 610 is connected to the hydrogen-side electrolysis product outlet of the electrolytic cell 100, the first gas is hydrogen and the second gas is oxygen.

[0052] In the upstream to downstream direction of the first electrolysis product flow path 610, the first separator 200 and the second separator 300 are distributed sequentially. The first gas coming out of the first separator 200 carries a small amount of electrolyte. The second separator 300 can further separate the electrolyte carried in the first gas, thereby increasing the separation space of the gas and liquid phases, improving the separation efficiency of the gas-liquid mixture, and helping to improve the purity of the first gas.

[0053] The gas-liquid mixture, initially separated in the first separator 200, is introduced into the second separator 300. This not only performs secondary gas-liquid separation on the gas-liquid mixture itself but also removes the second gas from the electrolyte in the second separator 300. Understandably, the first gas from the first separator 200 enters the second separator 300, located in the same electrolysis product flow path. This first gas can remove trace amounts of the second gas contained in the electrolyte of the second separator 300, reducing the amount of the second gas in the electrolyte returning to the electrolytic cell 100 and resulting in a higher purity of the subsequently generated first gas.

[0054] Specifically, please refer to Figure 1One of the separators in the first electrolysis product flow path 610 is connected to one of the separators in the second electrolysis product flow path 620 through a liquid-conducting connecting pipe 710. This allows the electrolyte containing a small amount of the second gas in the first separator 200 of the second electrolysis product flow path 620 to flow into the second separator 300 of the first electrolysis product flow path 610 through the liquid-conducting connecting pipe 710. As a result, the electrolyte in the second separator 300 of the first electrolysis product flow path 610 also contains a small amount of the second gas. The first gas from the first separator 200 of the first electrolysis product flow path 610 enters the second separator 300 of the same path and comes into contact with the electrolyte within the second separator 300. This process removes trace amounts of the second gas from the electrolyte. The purified electrolyte then flows back to the electrolytic cell 100, reducing the second gas content in the electrolyte. Consequently, the gas entering the first electrolysis product flow path 610 subsequently contains even less of the second gas, resulting in higher purity of the first gas. Although the extracted second gas initially affects the purity of the first gas during the initial operation of the hydrogen production system, as the system continues to operate, less and less second gas flows back to the electrolytic cell 100, and less and less can be extracted. This leads to higher purity of the first gas entering the next processing stage, thus contributing to improved purity. Therefore, the first gas produced during the initial operation of the hydrogen production system can be vented to ensure high purity of the first gas entering the next processing stage.

[0055] In one embodiment, there is one second separator 300, one of which is an electrolysis product flow path of hydrogen side electrolysis product flow path, and the hydrogen side electrolysis product flow path is provided with a liquid level difference regulating valve 410; both first separators 200 are provided with liquid level sensors 420, and the liquid level difference regulating valve 410 is electrically connected to the two liquid level sensors 420 to serve as a liquid level regulating device.

[0056] Please see Figure 1There is only one second separator 300, meaning that only the first electrolysis product flow path 610 has a second separator 300. A level sensor 420 is used to acquire the liquid levels of the two first separators 200. The level difference regulating valve 410 adjusts the liquid level of the first separator 200 in the second electrolysis product flow path 620 based on the data acquired by the level sensor 420, so that the liquid levels of the two first separators 200 are the same. Understandably, when the liquid level of the first separator 200 in the second electrolysis product flow path 620 is higher than that in the first separator 200 in the first electrolysis product flow path 610, the opening of the level difference regulating valve 410 can be reduced to increase the gas pressure inside the first separator 200 in the second electrolysis product flow path 620. This causes the electrolyte in the first separator 200 of the second electrolysis product flow path 620 to flow into the second separator 300 of the first electrolysis product flow path 610, thereby reducing the liquid level of the first separator 200 in the second electrolysis product flow path 620. Conversely, the opening of the liquid level difference regulating valve 410 is increased to raise the liquid level of the first separator 200 in the second electrolysis product flow path 620.

[0057] For ease of explanation, the following description uses an embodiment where the first electrolysis product flow path 610 is connected to the oxygen-side electrolysis product outlet of the electrolytic cell 100, and the second electrolysis product flow path 620 is connected to the hydrogen-side electrolysis product outlet of the electrolytic cell 100 as an example. Specifically, the first separator 200 of the first electrolysis product flow path 610 is an oxygen-side first separator 210; the second separator 300 of the first electrolysis product flow path 610 is an oxygen-side second separator 310; the first separator 200 of the second electrolysis product flow path 620 is a hydrogen-side first separator 220; and the second separator 300 of the second electrolysis product flow path 620 is a hydrogen-side second separator 320.

[0058] Please see Figure 1 and Figure 3Taking the corresponding embodiment shown in the figure as an example, in this embodiment, only the first electrolysis product flow path 610 is provided with a second separator 300, and the first electrolysis product flow path 610 is connected to the oxygen-side electrolysis product outlet of the electrolytic cell 100. That is, in the water electrolysis hydrogen production system, there are three separators: hydrogen-side first separator 220, oxygen-side second separator 310, and oxygen-side first separator 210. The gas phase pressures of the hydrogen-side first separator 220, oxygen-side second separator 310, and oxygen-side first separator 210 are P1, P2, and P3 respectively, and their liquid level heights are H1, H2, and H3 respectively. The real-time distance from the outlet of the gas guiding pipe 720 to the liquid surface of the oxygen-side second separator 310 is H0 (H0 changes with the liquid level H2). Then, the distance between the pipe opening of the gas guiding pipe 720 and the inner bottom wall of the oxygen-side second separator 310 is (H2-H0), where (H2-H0) is a constant value. Since the hydrogen-side first separator 220, the oxygen-side second separator 310, and the oxygen-side first separator 210 are connected by a liquid-conducting connecting pipe 710, according to Bernoulli's equation, H3 = H2 - H0, and H3 is a constant value.

[0059] The liquid level balance between the hydrogen-side first separator 220 and the oxygen-side first separator 210 is controlled by the liquid level difference regulating valve 410, which essentially controls the liquid level of the hydrogen-side first separator 220 to a constant value (H2-H0). Specifically, the liquid guide pipe 710 and the gas guide pipe 720 of the oxygen-side first separator 210 and the oxygen-side second separator 310 are connected. According to Bernoulli's equation, the liquid level of the oxygen-side first separator 210 is constant and will not change due to fluctuations in hydrogen production power. The liquid level of the hydrogen-side first separator 220 can be adjusted by the liquid level difference regulating valve 410 so that the liquid level of the hydrogen-side first separator 220 is H1 = H3, that is, H1 = (H2 - H0). When the liquid level values ​​of the oxygen-side first separator 210 and the hydrogen-side first separator 220 are both (H2 - H0), the liquid levels of the oxygen-side first separator 210 and the hydrogen-side first separator 220 reach equilibrium, so that the liquid levels of the oxygen-side first separator 210 and the hydrogen-side first separator 220 will not change due to fluctuations in hydrogen production power.

[0060] Understandably, when the liquid levels in the hydrogen-side first separator 220 and the oxygen-side first separator 210 are higher than (H2-H0), the liquid phase inside these separators will flow into the oxygen-side second separator 310 until their liquid levels reach (H2-H0). Conversely, when the liquid levels in these separators are lower than (H2-H0), the liquid phase inside the oxygen-side second separator 310 will flow into the hydrogen-side first separators 220 and 210 until their liquid levels reach (H2-H0). Therefore, the liquid levels in the oxygen-side first separator 210 and the hydrogen-side first separator 220 do not change with fluctuations in hydrogen production power, making them suitable for renewable energy-based hydrogen production and improving the operational stability of the hydrogen production system.

[0061] This is understandable; please refer to [link / reference]. Figure 2 In this embodiment, when only the first electrolysis product flow path 610 is equipped with a second separator 300, but the first electrolysis product flow path 610 is connected to the hydrogen-side electrolysis product outlet of the electrolyzer 100, the technical solution can make the liquid level of the hydrogen-side first separator 220 a constant value, and the liquid level of the oxygen-side first separator 210 can be adjusted by the liquid level difference regulating valve 410 so that the liquid level of the oxygen-side first separator 210 is the same as the liquid level of the hydrogen-side first separator 220. Thus, the liquid levels of the oxygen-side first separator 210 and the hydrogen-side first separator 220 are balanced, and their liquid levels do not change with the fluctuation of hydrogen production power. This is also suitable for renewable energy hydrogen production and improves the stability of the hydrogen production system operation.

[0062] In one implementation, please refer to Figure 5 A second separator 300 is provided in both electrolysis product flow paths. The second separator 300 on the second electrolysis product flow path 620 and its connected gas guide pipe 720 serve as liquid level regulating devices.

[0063] Referring to the principle of controlling the liquid level balance of the first separator 200 as described in the above embodiment, this embodiment connects the gas and liquid phases of the first separator 200 and the second separator 300 in the first electrolysis product flow path 610, which can reliably control the liquid level height of the oxygen-side first separator 210 to a constant value; at the same time, the gas and liquid phases of the first separator 200 and the second separator 300 in the second electrolysis product flow path 620 are connected, which can reliably control the liquid level height of the hydrogen-side first separator 220 to a constant value. Thus, the liquid levels of both the oxygen-side first separator 210 and the hydrogen-side first separator 220 can be controlled to a constant value, so that they do not change with the fluctuation of hydrogen production power, so as to better adapt to renewable energy hydrogen production, thereby further improving the stability and reliability of the hydrogen production system operation. The distance between the outlets of the two gas-conducting pipes 720 and the bottom wall of their respective second separators 300 is the same, so the (H2-H0) of the two second separators 300 is the same, and thus the liquid level setpoints of the two first separators 200 are also the same, both being (H2-H0), which helps to ensure the liquid level balance of the two first separators 200.

[0064] At this time, the second separator 300 on the second electrolysis product flow path 620 and its connected gas guide pipe 720 serve as liquid level regulating devices. There is no need to adjust the liquid level of the first separator 200 in the second electrolysis product flow path 620 through the liquid level difference regulating valve 410. The liquid levels of the first separators 200 in the two electrolysis product flow paths can be automatically maintained at a fixed value, which further improves the adaptability of the hydrogen production system to the coupled hydrogen production of renewable energy and improves the stability and reliability of the hydrogen production system operation.

[0065] Furthermore, by providing a second separator 300 in both electrolysis product flow paths, the oxygen-side second separator 310 in the first electrolysis product flow path 610 can further separate the oxygen from the oxygen-side first separator 210; and the hydrogen-side second separator 320 in the second electrolysis product flow path 620 can further separate the hydrogen from the hydrogen-side first separator 220. This simultaneously increases the separation space of the gas and liquid phases on both the hydrogen and oxygen sides, improves the separation efficiency of the gas-liquid mixture, and helps to improve the purity of both hydrogen and oxygen. Furthermore, the gas from the hydrogen-side first separator 220 can also remove trace amounts of oxygen from the electrolyte in the hydrogen-side second separator 320, and the gas from the oxygen-side first separator 210 can remove trace amounts of hydrogen from the electrolyte in the oxygen-side second separator 310. This achieves simultaneous gas stripping of hydrogen and oxygen, while reducing the hydrogen and oxygen content of the electrolyte returned to the electrolytic cell 100, resulting in higher purity hydrogen and oxygen produced subsequently.

[0066] In one implementation, please refer to Figure 5 The two second separators 300 are connected by a liquid guiding pipe 710.

[0067] When both electrolysis product flow paths are equipped with a second separator 300, one of the separators in the first electrolysis product flow path 610 and one of the separators in the second electrolysis product flow path 620 are connected through a liquid guiding pipe 710. It can be understood that one of the separators in the first electrolysis product flow path 610 is the second separator 300 in that electrolysis product flow path, and one of the separators in the second electrolysis product flow path 620 is the second separator 300 in that electrolysis product flow path. The two second separators 300 are connected through the liquid guiding pipe 710, which realizes the connection between the separators in the two electrolysis product flow paths, thereby realizing the automatic balance of the liquid level of the two first separators 200, effectively avoiding the problem of unstable liquid supply or gas backflow caused by uneven liquid level.

[0068] In one implementation, please refer to Figure 1 The water electrolysis hydrogen production system also has a return liquid flow path 630, the outlet end of which is connected to the electrolyzer 100. The return liquid flow path 630 includes two return liquid branches, and the inlet ends of the two return liquid branches are respectively connected to different separators.

[0069] The return flow path 630 is used to return the electrolyte collected in the separator to the electrolytic cell 100, forming a closed liquid circulation system. The electrolyte separated in the separator can be returned to the electrolytic cell 100 through the return flow path 630, thus reusing it as an electrolyte within the system, reducing the amount of fresh electrolyte needed and lowering operating costs. The return flow path 630 also helps maintain the liquid level balance of the entire system, reducing the problem of liquid level imbalance caused by excessively high or low liquid levels in individual separators, reducing the risk of equipment failure due to liquid level fluctuations, and enhancing the reliability of system operation.

[0070] In one embodiment, when only the first electrolysis product flow path 610 is equipped with the second separator 300, please refer to [reference needed]. Figure 1 The inlet ends of the two return liquid branches can be connected to the first separator 200 and the second separator 300 of the first electrolysis product flow path 610, respectively; please refer to Figure 6 Alternatively, the inlet ends of the two return liquid branches can be connected to the second separator 300 of the first electrolysis product flow path 610 and the first separator 200 of the second electrolysis product flow path 620, respectively; or the inlet ends of the two return liquid branches can be connected to the two first separators 200, respectively.

[0071] In one implementation, please refer to Figure 1 One of the return liquid branches has its inlet end connected to the second separator 300.

[0072] In the first electrolysis product flow path 610, the second separator 300 is located downstream of the first separator 200 and is used to further separate the initially separated first gas to remove residual electrolyte. Therefore, the return flow path can obtain purer electrolyte with lower gas content from the second separator 300, which helps improve the quality of the electrolyte returning to the electrolytic cell 100, increasing electrolysis efficiency and electrode stability. Furthermore, it can reduce level fluctuations caused by electrolyte reflux, further ensuring level stability in the first separator 200.

[0073] In another implementation, please refer to Figure 5 When both electrolysis product flow paths are equipped with a second separator 300, the inlet ends of the two return liquid branches are respectively connected to the two second separators 300.

[0074] The inlet ends of the two return liquid branches are respectively connected to the two second separators 300. The electrolyte returning from the two return liquid branches is purer and has a lower gas content, which helps to further improve the quality of the electrolyte returning to the electrolytic cell 100, improve electrolysis efficiency and electrode stability; it can also reduce the impact on the liquid level stability of the two first separators 200.

[0075] In one implementation, please refer to Figure 1 The air guide pipe 720 is inserted at the top of the second separator 300.

[0076] The gas-conducting connecting pipe 720 is inserted into the interior of the second separator 300 from the top and extends towards the bottom wall of the second separator 300, such that the outlet of the gas-conducting connecting pipe 720 is spaced apart from both the top and bottom walls of the second separator 300. By inserting the gas-conducting connecting pipe 720 into the top of the second separator 300, the electrolyte in the second separator 300 can be prevented from flowing back to the first separator 200 through the gas-conducting connecting pipe 720, thus affecting the gas-conducting function of the gas-conducting connecting pipe 720.

[0077] In other embodiments, the air guide tube 720 may also be inserted into the peripheral wall of the second separator 300.

[0078] In one embodiment, the ratio of the distance between the outlet of the air guide pipe 720 and the bottom wall of the second separator 300 to the height of the second separator 300 is K, where 0.2 ≤ K ≤ 0.6.

[0079] When 0.2 ≤ K ≤ 0.6, the distance between the outlet of the gas-conducting pipe 720 and the bottom wall of the second separator 300 is suitable, meaning (H2 - H0) is neither too large nor too small. This ensures the liquid level in the first separator 200 remains stable within a suitable range, guaranteeing its strong liquid storage capacity. When the hydrogen production rate is high, the two first separators 200 can also share the electrolyte load, preventing insufficient remaining space in the second separator 300 from simultaneously accommodating electrolyte from both first separators 200. This reduces the adverse effects of untimely liquid return on the operational stability of the hydrogen production system. Simultaneously, the large gas phase space within the first separator 200 and the second separator 300 provides a longer gas upward path, offering ample space for gas-liquid separation. This facilitates the full settling of residual droplets during the upward process, allowing them to be smoothly discharged with the gas, thereby effectively improving the purity of the collected gas.

[0080] Of course, in other embodiments, the ratio K can be set to a range less than 0.2 or greater than 0.6 as needed.

[0081] In one embodiment, one of the electrolysis product flow paths is an oxygen-side electrolysis product flow path. The oxygen-side electrolysis product flow path is provided with a pressure regulating valve 510. The first separator 200 or the second separator 300 of the oxygen-side electrolysis product flow path is provided with a pressure sensor 520. The pressure regulating valve 510 is electrically connected to the pressure sensor 520.

[0082] Please see Figure 1 Pressure sensor 520 can be installed on the first separator 200 to acquire pressure data within the first separator 200; please refer to [link / reference]. Figure 7 The pressure sensor 520 can also be installed on the second separator 300 to acquire pressure data within the first separator 200. By setting the pressure sensor 520 to monitor the pressure status within the separator in real time and feeding the signal back to the pressure regulating valve 510, closed-loop control of the pressure in the oxygen-side electrolysis product flow path is achieved. This not only improves the stability and safety of oxygen-side gas emissions but also helps optimize the pressure difference control between the hydrogen and oxygen sides, thereby enhancing the overall operational reliability of the system.

[0083] The above description is merely an exemplary embodiment of this application and does not limit the scope of protection of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. A water electrolysis hydrogen production system, characterized in that, The water electrolysis hydrogen production system includes an electrolyzer (100) and a separator. The electrolyzer (100) is connected to two electrolysis product flow paths, and the electrolysis product flow paths are equipped with the separator. The two electrolytic product flow paths are a first electrolytic product flow path (610) and a second electrolytic product flow path (620), and each electrolytic product flow path is provided with a first separator (200). At least in the first electrolytic product flow path (610), a second separator (300) is provided downstream of the first separator (200). The separator includes a first separator (200) and a second separator (300), and one of the separators in the first electrolysis product flow path (610) is connected to one of the separators in the second electrolysis product flow path (620) through a liquid guiding pipe (710). The first separator (200) and the second separator (300) in the same electrolysis product flow path are connected by a liquid-conducting connecting pipe (710) and a gas-conducting connecting pipe (720). The electrolysis products of the first separator (200) flow to the second separator (300) through the gas-conducting connecting pipe (720). The outlet of the gas-conducting connecting pipe (720) and the top and bottom walls of the second separator (300) are spaced apart. The water electrolysis hydrogen production system includes a liquid level regulating device, which is used to regulate the liquid level of the first separator (200) in the second electrolysis product flow path (620).

2. The water electrolysis hydrogen production system as described in claim 1, characterized in that, The number of the second separator (300) is set to one, wherein one of the electrolysis product flow paths is a hydrogen-side electrolysis product flow path, and the hydrogen-side electrolysis product flow path is provided with a liquid level difference regulating valve (410). Each of the two first separators (200) is equipped with a liquid level sensor (420), and the liquid level difference regulating valve (410) is electrically connected to the two liquid level sensors (420) to serve as the liquid level regulating device.

3. The water electrolysis hydrogen production system as described in claim 2, characterized in that, The water electrolysis hydrogen production system also has a return liquid flow path (630), the outlet end of which is connected to the electrolytic cell (100). The return liquid flow path (630) includes two return liquid branches, and the inlet ends of the two return liquid branches are respectively connected to different separators.

4. The water electrolysis hydrogen production system as described in claim 3, characterized in that, The inlet end of one of the return liquid branches is connected to the second separator (300).

5. The water electrolysis hydrogen production system as described in claim 1, characterized in that, Both of the electrolysis product flow paths are provided with the second separator (300), and the second separator (300) on the second electrolysis product flow path (610) and its connected gas guide pipe (720) serve as the liquid level regulating device.

6. The water electrolysis hydrogen production system as described in claim 5, characterized in that, The two second separators (300) are connected by a liquid-conducting connecting pipe (710).

7. The water electrolysis hydrogen production system as described in claim 5, characterized in that, The water electrolysis hydrogen production system also has a return liquid flow path (630), the outlet end of which is connected to the electrolytic cell (100). The return liquid flow path (630) includes two return liquid branches, and the inlet ends of the two return liquid branches are respectively connected to two second separators (300).

8. The water electrolysis hydrogen production system as described in claim 1, characterized in that, The air guide pipe (720) is inserted at the top of the second separator (300).

9. The water electrolysis hydrogen production system as described in claim 1, characterized in that, The ratio of the distance between the outlet of the air-conducting pipe (720) and the bottom wall of the second separator (300) to the height of the second separator (300) is K, where 0.2 ≤ K ≤ 0.

6.

10. The water electrolysis hydrogen production system according to any one of claims 1 to 9, characterized in that, One of the electrolysis product flow paths is an oxygen-side electrolysis product flow path, which is equipped with a pressure regulating valve (510). The first separator (200) or the second separator (300) of the oxygen-side electrolysis product flow path is equipped with a pressure sensor (520), and the pressure regulating valve (510) is electrically connected to the pressure sensor (520).

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