Water electrolysis hydrogen production system

Abstract

The utility model discloses a water electrolysis hydrogen production system, and relates to the technical field of hydrogen production, the water electrolysis hydrogen production system comprises an electrolytic tank, a hydrogen side separator, an oxygen side separator and a communicating pipe, the electrolytic tank is provided with a hydrogen side electrolysis product outlet and an oxygen side electrolysis product outlet; the hydrogen side separator is communicated with the hydrogen side electrolysis product outlet; the oxygen side separator is communicated with the oxygen side electrolysis product outlet; the number of the communicating pipes is not less than two, the hydrogen side separator and the oxygen side separator are connected through a plurality of communicating pipes which are connected in parallel, and switch valves are arranged on the communicating pipes. According to the technical scheme, the plurality of communicating pipes connected in parallel are arranged between the hydrogen-side separator and the oxygen-side separator, and the switching valves are arranged on the communicating pipes, so that the water electrolysis hydrogen production system can realize the balance of the liquid level of alkali liquor of the hydrogen-side separator and the oxygen-side separator under different working conditions; and the working load range of the water electrolysis hydrogen production system is comprehensively considered, so that the operation stability of the water electrolysis hydrogen production system is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen production, in particular to a water electrolysis hydrogen production system. BACKGROUND

[0002] In the existing water electrolysis hydrogen production system, a communication pipe is connected at the bottom of the hydrogen separator and the oxygen separator. Under variable power hydrogen production conditions, the working load range of the hydrogen production system cannot be fully considered, resulting in frequent fluctuations in the liquid level of the hydrogen separator and the oxygen separator, affecting the stability of hydrogen production. CONTENT OF THE UTILITY MODEL

[0003] The main purpose of the present application is to provide a water electrolysis hydrogen production system, which aims to improve the stability of the water electrolysis hydrogen production system.

[0004] To achieve the above purpose, the water electrolysis hydrogen production system provided by the present application comprises:

[0005] The electrolytic tank has a hydrogen-side electrolysis product outlet and an oxygen-side electrolysis product outlet.

[0006] The hydrogen-side separator is in communication with the hydrogen-side electrolysis product outlet.

[0007] The oxygen-side separator is in communication with the oxygen-side electrolysis product outlet.

[0008] The communication pipe is not less than two, and the hydrogen-side separator and the oxygen-side separator are connected through multiple parallel communication pipes, and each communication pipe is provided with a switch valve.

[0009] In an embodiment, the water electrolysis hydrogen production system further comprises a controller, the controller is electrically connected with the switch valve, and the controller is used to control the switch valve to be in an open state or a closed state.

[0010] In an embodiment, the communication pipe has two, which are configured as a first communication pipe and a second communication pipe, the first communication pipe is provided with a first switch valve, the second communication pipe is provided with a second switch valve, and the diameter of the first communication pipe is greater than that of the second communication pipe.

[0011] In an embodiment, the communication pipe has two, which are configured as a first communication pipe and a second communication pipe, the first communication pipe is provided with a first switch valve, the second communication pipe is provided with a second switch valve, and the length of the first communication pipe is less than that of the second communication pipe.

[0012] In an embodiment, the controller is electrically connected with the power supply of the electrolytic tank, and the controller is used to control the first switch valve and the second switch valve to be in an open state or a closed state according to the operating parameters of the electrolytic tank.

[0013] In an embodiment, the parameter W is defined as a ratio of an actual operating power of the electrolyzer to a rated power of the electrolyzer,

[0014] When 30%≤W<50%, the controller is configured to control the first switch valve to be in a closed state and the second switch valve to be in an open state;

[0015] When 50%≤W≤110%, the controller is configured to control the first switch valve to be in an open state and the second switch valve to be in a closed state.

[0016] In an embodiment, the electrolyzer further has a liquid return port, the hydrogen-side separator and the oxygen-side separator are in communication with the liquid return port through a liquid return flow path, and the water electrolysis hydrogen production system further comprises a flow meter arranged on the liquid return flow path, the flow meter being configured to obtain an actual operating circulation amount of the alkali liquor on the liquid return flow path, and the controller is electrically connected to the flow meter.

[0017] In an embodiment, the actual operating circulation amount is Q, the minimum safe circulation amount of the alkali liquor on the liquid return flow path is Q min , and the maximum allowable circulation amount is Q max .

[0018] When Q min ≤Q<0.5Q max , the controller is configured to control the first switch valve to be in a closed state and the second switch valve to be in an open state.

[0019] When 0.5Q max ≤Q≤Q max , the controller is configured to control the first switch valve to be in an open state and the second switch valve to be in a closed state.

[0020] In an embodiment, the actual operating circulation amount is Q, the minimum safe circulation amount of the alkali liquor on the liquid return flow path is Q min , and the maximum allowable circulation amount is Q max .

[0021] When Q min ≤Q<0.4Q max , the controller is configured to control the first switch valve to be in a closed state and the second switch valve to be in an open state.

[0022] When 0.4Q max ≤Q<0.6Q max , the controller is configured to control the first switch valve to be in an open state and the second switch valve to be in a closed state.

[0023] When 0.6Q max ≤Q≤Q max .When the controller is configured to control the first switch valve and the second switch valve to be in an open state.

[0024] In an embodiment, the electrolyzer further has a back liquid outlet, the hydrogen-side separator and the oxygen-side separator are communicated with the back liquid outlet through a back liquid flow path, and the water electrolysis hydrogen production system further comprises a flow meter arranged on the back liquid flow path, the flow meter being configured to obtain an actual operation circulation amount of the alkali liquor on the back liquid flow path, the controller is electrically connected with the flow meter, the actual operation circulation amount is Q, the minimum safe circulation amount of the alkali liquor on the back liquid flow path is Q min , and the maximum allowable circulation amount is Q max . The diameters and lengths of the plurality of communication pipes are the same.

[0025] In an embodiment, the communication pipes are two, when Q min ≤ Q < 0.5Q max , the switch valve on one of the communication pipes is in an open state, and the switch valve on the other communication pipe is in a closed state; when 0.5Q max ≤ Q ≤ Q max , the switch valves on both of the communication pipes are in an open state.

[0026] In an embodiment, the communication pipes are three, when Q min ≤ Q < 0.4Q max , the switch valve on one of the communication pipes is in an open state, and the switch valves on the other two communication pipes are in a closed state; when 0.4Q max ≤ Q ≤ 0.7Q max , the switch valves on two of the communication pipes are in an open state, and the switch valve on the other communication pipe is in a closed state; when 0.7Q max ≤ Q ≤ Q max , the switch valves on all of the communication pipes are in an open state.

[0027] The technical scheme of the present application can open the switch valves on the communication pipes or open the switch valves on different numbers of communication pipes according to the working condition of the water electrolysis hydrogen production system, so that the water electrolysis hydrogen production system can control the flow of the alkali liquor between the hydrogen-side separator and the oxygen-side separator under different working conditions, balance the liquid levels of the hydrogen-side separator and the oxygen-side separator, comprehensively consider the working load range of the water electrolysis hydrogen production system, reduce the risk of frequent fluctuations in the liquid levels of the hydrogen-side separator and the oxygen-side separator, improve the stability of the water electrolysis hydrogen production system, reduce the possibility of hydrogen-oxygen mutual cross, and improve the purity of hydrogen and oxygen. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some of the embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings shown.

[0029] Figure 1 Structure schematic diagram of an embodiment of a water electrolysis hydrogen production system provided by the present application;

[0030] Figure 2 Structure schematic diagram of another embodiment of a water electrolysis hydrogen production system provided by the present application;

[0031] Figure 3 Structure schematic diagram of still another embodiment of a water electrolysis hydrogen production system provided by the present application.

[0032] Explanation of reference numerals:

[0033] 10, water electrolysis hydrogen production system; 100, electrolytic cell; 110, hydrogen side electrolysis product outlet; 120, oxygen side electrolysis product outlet; 130, liquid return port; 210, hydrogen side separator; 220, oxygen side separator; 310, first communication pipe; 320, second communication pipe; 410, first on-off valve; 420, second on-off valve; 500, controller; 600, flow meter; 700, booster pump; 800, heat exchanger; P, liquid return flow path.

[0034] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] It should be noted that if the present application embodiments involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between the components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0037] In addition, if the description of "first", "second" and the like is involved in the embodiments of the present application, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included at least one of the features. In addition, if "and / or" or "and / or" appears throughout the text, it means that the three parallel schemes are included, for example, "A and / or B" includes A scheme, or B scheme, or A and B scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor in the protection scope claimed by the present application.

[0038] The present application proposes a water electrolysis hydrogen production system 10.

[0039] Please refer to Figure 1 and Figure 2 In an embodiment of the present application, the water electrolysis hydrogen production system 10 includes an electrolytic tank 100, a hydrogen side separator 210, an oxygen side separator 220 and a communication pipe, the electrolytic tank 100 has a hydrogen side electrolysis product outlet 110 and an oxygen side electrolysis product outlet 120; the hydrogen side separator 210 is in communication with the hydrogen side electrolysis product outlet 110; the oxygen side separator 220 is in communication with the oxygen side electrolysis product outlet 120; the communication pipe is not less than two, the hydrogen side separator 210 and the oxygen side separator 220 are connected through a plurality of parallel communication pipes, and the communication pipe is provided with a switch valve.

[0040] The electrolytic tank 100 of the water electrolysis hydrogen production system 10 can decompose water into hydrogen and oxygen. The gas generated on the corresponding electrode surface of the electrolytic tank 100 will carry a small amount of alkali liquor. The electrolysis product from the hydrogen side electrolysis product outlet 110 of the electrolytic tank 100 is a hydrogen-alkali gas-liquid mixture, and the electrolysis product from the oxygen side electrolysis product outlet 120 is an oxygen-alkali gas-liquid mixture.

[0041] The hydrogen side separator 210 is connected with the hydrogen side electrolysis product outlet 110 of the electrolytic tank 100, and is used for preliminary separation of the alkali liquor in the hydrogen-alkali gas-liquid mixture. After the hydrogen-alkali gas-liquid mixture is preliminarily separated in the hydrogen side separator 210, the liquid phase remains in the hydrogen side separator 210. The oxygen side separator 220 is connected with the oxygen side electrolysis product outlet 120 of the electrolytic tank 100, and is used for preliminary separation of the alkali liquor in the oxygen-alkali gas-liquid mixture. After the oxygen-alkali gas-liquid mixture is preliminarily separated in the oxygen side separator 220, the liquid phase remains in the oxygen side separator 220.

[0042] In the water electrolysis process, due to the different gas generation rates (the volume ratio of hydrogen to oxygen is 2:1), it can cause the liquid level difference of the alkali liquor in the hydrogen side separator 210 and the oxygen side separator 220. The hydrogen side separator 210 and the oxygen side separator 220 are connected through a plurality of parallel communication pipes, which are arranged near the bottom of the hydrogen side separator 210 and the oxygen side separator 220, so that the alkali liquor in the hydrogen side separator 210 and the oxygen side separator 220 can flow through the communication pipe, balance the liquid level of the alkali liquor in the hydrogen side separator 210 and the oxygen side separator 220, and ensure the stability of the water electrolysis hydrogen production system 10.

[0043] Each communication pipe is provided with a switch valve for controlling the flow of alkali liquor between the hydrogen side separator 210 and the oxygen side separator 220. The switch valve can be flexibly adjusted according to actual needs. The water electrolysis hydrogen production system 10 can selectively open the switch valve on the communication pipe or open the switch valve on different numbers of communication pipes according to its own working conditions.

[0044] Specifically, the sizes of the plurality of communication pipes can be different. When the liquid level difference of the two separators is large, the switch valve on the communication pipe with larger diameter or smaller length can be opened to make the alkali liquor flow quickly through the communication pipe; when the liquid level difference of the two separators is small, the switch valve on the communication pipe with smaller diameter or larger length can be opened to provide more stable flow. The sizes of the plurality of communication pipes can also be the same. When the liquid level difference of the two separators is large, the switch valves on the plurality of communication pipes can be opened to enable the liquid levels of the hydrogen side separator 210 and the oxygen side separator 220 to be quickly matched; when the liquid level difference of the two separators is small, the switch valves on fewer communication pipes can be opened, or even only the switch valve on one communication pipe can be opened.

[0045] The hydrogen side separator 210 and the oxygen side separator 220 are connected through a plurality of parallel communication pipes, and the on-off of the communication pipes is controlled through the switch valves on the communication pipes, which can make the communication pipes more suitable for the requirements of the water electrolysis hydrogen production system 10 under different working conditions, be conducive to comprehensively considering the working load range of the water electrolysis hydrogen production system 10, reduce the risk of frequent liquid level fluctuation of the hydrogen side separator 210 and the oxygen side separator 220, thereby improving the operation stability and reliability of the water electrolysis hydrogen production system 10; at the same time, matching different communication pipes under different operating conditions can reduce the gas mutual mixing between the hydrogen side separator 210 and the oxygen side separator 220, thereby being conducive to improving the purity of the gas.

[0046] The technical solution of the present application sets multiple parallel communication pipes between the hydrogen side separator 210 and the oxygen side separator 220, and sets on-off valves on the communication pipes, so that the water electrolysis hydrogen production system 10 can selectively open the on-off valves on the communication pipes or open the on-off valves on different numbers of communication pipes according to its own working conditions, so that the water electrolysis hydrogen production system 10 can control the flow of alkali between the hydrogen side separator 210 and the oxygen side separator 220 under different working conditions, balance the alkali levels of the hydrogen side separator 210 and the oxygen side separator 220, and comprehensively consider the working load range of the water electrolysis hydrogen production system 10, so as to reduce the risk of frequent fluctuations in the liquid levels of the hydrogen side separator 210 and the oxygen side separator 220, thereby improving the stability of the water electrolysis hydrogen production system 10; at the same time, it reduces the possibility of hydrogen-oxygen mutual mixing and improves the purity of hydrogen and oxygen.

[0047] In an embodiment, referring to Figure 1 and Figure 2 , the water electrolysis hydrogen production system 10 further comprises a controller 500, the controller 500 is electrically connected with the on-off valves, and the controller 500 is used for controlling the on-off valves to be in an open state or a closed state.

[0048] The controller 500 is an intelligent control unit in the water electrolysis hydrogen production system 10, which realizes automatic control of the open state and the closed state of the on-off valves through electrical connection with the on-off valves. The controller 500 can automatically adjust the state of the on-off valves according to preset conditions or real-time monitoring data such as alkali level, gas pressure, alkali flow or running load of the water electrolysis hydrogen production system 10, so that the alkali flows between the two separators to achieve liquid level balance, thereby optimizing the operation of the water electrolysis hydrogen production system 10. The setting of the controller 500 enables the water electrolysis hydrogen production system 10 to automatically adjust the state of the on-off valves without manual intervention, greatly improving the automation level of the water electrolysis hydrogen production system 10, reducing the working intensity of the operating personnel, and reducing the possibility of human operation errors. Through real-time monitoring and automatic adjustment, the controller 500 can quickly respond to changes in the liquid level, ensure that the alkali level remains balanced, reduce the risk of frequent fluctuations in the liquid levels of the hydrogen side separator 210 and the oxygen side separator 220, and help maintain stable operation of the water electrolysis hydrogen production system 10.

[0049] In other embodiments, the state of the on-off valve can also be controlled manually.

[0050] In an embodiment, referring to Figure 1 , the communication pipe has two, which are configured as a first communication pipe 310 and a second communication pipe 320, the first communication pipe 310 is provided with a first on-off valve 410, and the second communication pipe 320 is provided with a second on-off valve 420, the diameter of the first communication pipe 310 is greater than that of the second communication pipe 320.

[0051] The first communication pipe 310 is provided with a first switch valve 410, and the first communication pipe 310 has a larger diameter and can provide a higher flow rate for controlling the flow of a larger amount of alkali solution to quickly balance the liquid level of the alkali solution between the hydrogen-side separator 210 and the oxygen-side separator 220. The second communication pipe 320 is provided with a second switch valve 420, and the second communication pipe 320 has a smaller diameter and is used to control the flow of a smaller amount of alkali solution to provide more stable flow, and can also finely adjust the liquid level difference between the hydrogen-side separator 210 and the oxygen-side separator 220 when the liquid level difference is small, thereby avoiding liquid level fluctuations caused by too high a flow rate. The design of the communication pipes with different diameters enables the water electrolysis hydrogen production system 10 to adapt to a wider range of working conditions. In addition, the fast regulation of a large amount of flow is mainly borne by the first communication pipe 310, and the fine regulation of a small amount of flow is completed by the second communication pipe 320, and this division of labor can reduce the frequency of use of a single communication pipe and its switch valve, thereby reducing equipment wear.

[0052] In another embodiment, referring to Figure 1 and Figure 2 , the length of the first communication pipe 310 is less than the length of the second communication pipe 320.

[0053] The first communication pipe 310 has a shorter length and smaller fluid resistance, and can provide a higher flow rate and faster response speed, thereby significantly shortening the liquid level balancing time. The second communication pipe 320 has a longer length and larger fluid resistance, and has a relatively lower flow rate, and can provide more stable flow characteristics. When the liquid level difference of the alkali solution between the hydrogen-side separator 210 and the oxygen-side separator 220 is large, the controller 500 preferentially opens the first switch valve 410 to quickly balance the liquid level through the first communication pipe 310. When the liquid level difference is reduced to a certain extent, the controller 500 closes the first switch valve 410 and opens the second switch valve 420 to finely adjust the liquid level through the second communication pipe 320, thereby providing more stable low-flow flow and avoiding liquid level fluctuations caused by excessive regulation.

[0054] In yet another embodiment, referring to Figure 1 and Figure 2 , the diameter of the first communication pipe 310 is greater than the diameter of the second communication pipe 320, and the length of the first communication pipe 310 is less than the length of the second communication pipe 320.

[0055] The first communication pipe 310 not only has a larger diameter, but also has a shorter length; the second communication pipe 320 has a smaller diameter and a longer length. The design combines the diameter and length characteristics of the communication pipe to achieve different flow characteristics and application scenarios. The first communication pipe 310 has a shorter length and a larger diameter, the fluid resistance of the first communication pipe 310 is smaller, which can provide higher flow and faster response speed. The second communication pipe 320 has a longer length and a smaller diameter, the second communication pipe 320 allows smaller flow of the alkali solution, but can provide more stable flow characteristics.

[0056] In other embodiments, the plurality of communication pipes further includes a third communication pipe, the third communication pipe is provided with a third switch valve, and the diameter and length of the third communication pipe are different from those of the first communication pipe 310 and the second communication pipe 320. The diameter of the third communication pipe can be greater than that of the first communication pipe 310, or less than that of the second communication pipe 320, or less than that of the first communication pipe 310 and greater than that of the second communication pipe 320. The length of the third communication pipe can be less than that of the first communication pipe 310, or greater than that of the second communication pipe 320, or greater than that of the first communication pipe 310 and less than that of the second communication pipe 320.

[0057] In an embodiment, referring to Figure 1 The controller 500 is electrically connected with the power supply of the electrolytic cell 100, and the controller 500 is used to control the first switch valve 410 and the second switch valve 420 to be in an open state or a closed state according to the operating parameters of the electrolytic cell 100.

[0058] The controller 500 can comprehensively judge and control the state of the first switch valve 410 and the second switch valve 420 according to the operating parameters (such as current, voltage, operating power of the electrolytic cell 100, etc.) of the electrolytic cell 100. The operating parameters of the electrolytic cell 100 directly determine the generation rate of hydrogen and oxygen, thereby affecting the change of the alkali solution level in the hydrogen-side separator 210 and the oxygen-side separator 220. The controller 500 can judge the liquid level change trend by monitoring the operating parameters of the electrolytic cell 100 in real time, and adjust the state of the switch valve to realize liquid level balance. The dynamic control mode of the controller 500 based on the operating parameters of the electrolytic cell 100 can better adapt to the changes of the working conditions of the water electrolysis hydrogen production system 10, which is beneficial to avoid the liquid level fluctuation caused by lagging adjustment, and ensure that the liquid level is in a balanced state.

[0059] When the electrolyzer 100 is running in a high load state, the gas generation rate is fast, which can cause a large difference in liquid level. At this time, the controller 500 will preferentially open the first switch valve 410 to quickly balance the liquid level using the first communication pipe 310. When the electrolyzer 100 is running in a low load state or tends to be stable, the gas generation rate is slow, and the difference in liquid level is small. At this time, the controller 500 will close the first switch valve 410 and only open the second switch valve 420 to fine-tune using the second communication pipe 320.

[0060] In an embodiment, referring to Figure 1 , the parameter W is defined as the ratio of the actual operating power of the electrolyzer 100 to the rated power. When 30%≤W<50%, the controller 500 is used to control the first switch valve 410 to be in a closed state and the second switch valve 420 to be in an open state; when 50%≤W≤110%, the controller 500 is used to control the first switch valve 410 to be in an open state and the second switch valve 420 to be in a closed state.

[0061] The parameter W is defined as the ratio of the actual operating power of the electrolyzer 100 to the rated power, which is used to quantify the load state of the electrolyzer 100. The value range of W is 30%≤W≤110%, where W=100% indicates that the electrolyzer 100 is running at rated power.

[0062] When 30%≤W<50%, the electrolyzer 100 is in a low load state, the gas generation rate is low, and the caustic liquid level changes slowly. The controller 500 controls the first switch valve 410 to be in a closed state and the second switch valve 420 to be in an open state, fine-tunes the caustic liquid level using the second communication pipe 320, and avoids liquid level fluctuations caused by excessive flow rate.

[0063] When 50%≤W≤110%, the electrolyzer 100 is in a medium-high load state, the gas generation rate is high, and the caustic liquid level changes rapidly. The controller 500 controls the first switch valve 410 to be in an open state and the second switch valve 420 to be in a closed state, quickly balances the caustic liquid level using the first communication pipe 310, and ensures that the liquid level quickly recovers to be stable.

[0064] By dynamically adjusting the state of the switch valve according to the value of W, the water electrolysis hydrogen production system 10 can better adapt to the operating requirements under different load conditions, improving the adaptability and flexibility of the water electrolysis hydrogen production system 10. In a low load state, closing the first switch valve 410 can reduce unnecessary large flow, thereby reducing the energy consumption of the water electrolysis hydrogen production system 10. In a medium-high load state, timely opening the first switch valve 410 can quickly balance the liquid level, avoiding energy waste caused by a large difference in liquid level. At the same time, reasonable flow distribution also reduces the fluid resistance in the pipeline, further prolonging the service life of the equipment. Reasonable flow distribution also reduces the residence time in the pipeline, optimizing the caustic liquid circulation efficiency.

[0065] In an embodiment, referring to Figure 2 , the electrolytic tank 100 also has a back-liquid port 130, the hydrogen-side separator 210 and the oxygen-side separator 220 are communicated with the back-liquid port 130 through a back-liquid flow path P, and the water electrolysis hydrogen production system 10 further includes a flow meter 600 arranged on the back-liquid flow path P, the flow meter 600 being configured to obtain an actual operation circulation amount of the alkali solution on the back-liquid flow path P, and the controller 500 is electrically connected with the flow meter 600.

[0066] The back-liquid port 130 on the electrolytic tank 100 is configured to guide the alkali solution in the hydrogen-side separator 210 and the oxygen-side separator 220 back into the electrolytic tank 100, thereby ensuring the continuous circulation of the alkali solution in the water electrolysis hydrogen production system 10 and avoiding the waste or excessive accumulation of the alkali solution. The back-liquid flow path P connects the hydrogen-side separator 210, the oxygen-side separator 220 and the back-liquid port 130 of the electrolytic tank 100, thereby forming a complete alkali solution circulation path, and the alkali solution can return to the electrolytic tank 100 from the separators through the back-liquid flow path P, thereby maintaining the stable operation of the water electrolysis hydrogen production system 10. The flow meter 600 is arranged on the back-liquid flow path P and is configured to monitor the actual operation circulation amount of the alkali solution in real time. The controller 500 is electrically connected with the flow meter 600, can obtain the data of the flow meter 600, and dynamically adjusts the states of the first switch valve 410 and the second switch valve 420 according to the actual circulation amount, so as to balance the liquid level of the alkali solution. The controller 500 can more accurately adjust the states of the switch valves based on the real-time data provided by the flow meter 600, thereby improving the control precision of the liquid level balancing and the alkali solution circulation and avoiding the liquid level fluctuation caused by the excessive or insufficient circulation amount.

[0067] In an embodiment, referring to Figure 2 , the actual operation circulation amount is Q, the minimum safe circulation amount of the alkali solution on the back-liquid flow path P is Q min , and the maximum allowable circulation amount is Q max When Q min ≤ Q < 0.5Q max , the controller 500 is configured to control the first switch valve 410 to be in a closed state and the second switch valve 420 to be in an open state; and when 0.5Q max ≤ Q ≤ Q max , the controller 500 is configured to control the first switch valve 410 to be in an open state and the second switch valve 420 to be in a closed state.

[0068] Q is the actual circulation flow of the alkali solution on the back-liquid flow path P, which is monitored in real time by the flow meter 600. Q min is the minimum safe circulation amount of the alkali solution on the back-liquid flow path P, which is monitored in real time by the flow meter 600. Q maxQmax is the maximum amount of alkali solution circulation allowed by the water electrolysis hydrogen production system 10, and exceeding this value may cause energy waste or pipeline overload.

[0069] When Q min ≤ Q < 0.5Q max , the alkali solution flow is small, the alkali solution flows slowly, and the liquid level changes little. At this time, the controller 500 controls the first switch valve 410 to be in a closed state, the second switch valve 420 to be in an open state, and the alkali solution liquid levels of the hydrogen side separator 210 and the oxygen side separator 220 are finely adjusted through the second communication pipe 320 to avoid instability caused by large flow.

[0070] When 0.5Q max ≤ Q ≤ Q max , the alkali solution flow is large, the alkali solution flows quickly, and the liquid level changes greatly. At this time, the controller 500 controls the first switch valve 410 to be in an open state, the second switch valve 420 to be in a closed state, and the alkali solution liquid levels of the hydrogen side separator 210 and the oxygen side separator 220 are quickly balanced through the first communication pipe 310 to ensure that the alkali solution circulation amount remains within a reasonable range.

[0071] By dynamically adjusting the state of the switch valve according to the Q value, the water electrolysis hydrogen production system 10 can better adapt to the operating requirements under different circulation amounts of alkali solution, improving the adaptability and flexibility of the water electrolysis hydrogen production system 10. At low circulation amounts, closing the first switch valve 410 can reduce unnecessary large flow, thereby reducing the energy consumption of the water electrolysis hydrogen production system 10. At medium and high circulation amounts, timely opening of the first switch valve 410 can quickly balance the liquid level, avoiding energy waste caused by excessive liquid level difference. At the same time, reasonable flow distribution also reduces the fluid resistance in the pipeline, further prolonging the service life of the equipment. Reasonable flow distribution also reduces the residence time in the pipeline, optimizing the alkali solution circulation efficiency. In other embodiments, the division range of low circulation amount and high circulation amount can not be limited to this.

[0072] In another embodiment, referring to Figure 2 , the actual operating circulation amount is Q, the minimum safe circulation amount of alkali solution on the liquid return flow path P is Q min , and the maximum allowable circulation amount is Q max When Q min ≤ Q < 0.4Q max , the controller 500 is configured to control the first switch valve 410 to be in a closed state and the second switch valve 420 to be in an open state; when 0.4Q max ≤ Q < 0.6Q max , the controller 500 is configured to control the first switch valve 410 to be in an open state and the second switch valve 420 to be in a closed state; and when 0.6Q max ≤ Q ≤ Q maxWhen Q

[0073] When Q min ≤ Q < 0.4Q max , the alkali flows slowly and the liquid level changes slightly. At this time, the controller 500 controls the first switch valve 410 to be in a closed state and the second switch valve 420 to be in an open state. The liquid levels of the hydrogen-side separator 210 and the oxygen-side separator 220 are finely adjusted through the second communication pipe 320 to avoid instability caused by large flow.

[0074] When 0.4Q max ≤ Q < 0.6Q max , the alkali flows moderately and the liquid level changes greatly. At this time, the controller 500 controls the first switch valve 410 to be in an open state and the second switch valve 420 to be in a closed state. The first communication pipe 310 provides higher flow to quickly balance the liquid level.

[0075] When 0.6Q max ≤ Q ≤ Q max , the alkali flows quickly and the liquid level changes dramatically. At this time, the controller 500 controls the first switch valve 410 and the second switch valve 420 to be in an open state. The first communication pipe 310 and the second communication pipe 320 need to be jointly adjusted to cope with greater alkali circulation demand to ensure the stability of the water electrolysis hydrogen production system 10.

[0076] By dividing the actual circulation amount into three intervals, the water electrolysis hydrogen production system 10 can more accurately adapt to the operating requirements under different working conditions. This hierarchical control method significantly improves the adaptability and flexibility of the water electrolysis hydrogen production system 10. In other embodiments, the value range of the three intervals of the actual circulation amount can not be limited to this.

[0077] It is worth mentioning that the controller 500 controls the opening and closing of the switch valves and thus the opening and closing of the communication pipes through either the alkali flow or the operating parameters of the electrolyzer 100, which is easier to control.

[0078] In an embodiment, please refer to Figure 2 , the diameters and lengths of the plurality of communication pipes are the same.

[0079] The diameters and lengths of the plurality of communication pipes are the same, that is, the specifications of the plurality of communication pipes are the same. The water electrolysis hydrogen production system 10 can open the switch valves of different numbers of communication pipes according to its own working conditions. The working conditions of the water electrolysis hydrogen production system 10 can be judged according to the range of the actual operating circulation amount Q of the alkali on the liquid return flow path. The value range of the actual operating circulation amount Q is between Q min and Q max , wherein Qmin Qmin is the minimum safe circulation amount of the alkali solution on the return flow path P max Qmax is the maximum allowable circulation amount of the alkali solution on the return flow path P.

[0080] In an embodiment, referring to Figure 2 , the communication pipe has two, when Q min ≤ Q < 0.5Q max , the on-off valve on one of the communication pipes is in an open state, and the on-off valve on the other communication pipe is in a closed state; when 0.5Q max ≤ Q ≤ Q max , the on-off valves on both of the communication pipes are in an open state.

[0081] When Q min ≤ Q < 0.5Q max , the flow of the alkali solution is small, the flow of the alkali solution is slow, and the change of the liquid level is small. At this time, the controller 500 controls the on-off valve on one of the communication pipes to be in an open state, and the on-off valve on the other communication pipe to be in a closed state, so that the liquid levels of the hydrogen-side separator 210 and the oxygen-side separator 220 are communicated only through one communication pipe to adjust the liquid level balance of the alkali solution of the two, and to avoid instability caused by large flow.

[0082] When 0.5Q max ≤ Q ≤ Q max , the flow of the alkali solution is large, the flow of the alkali solution is fast, and the change of the liquid level is large. At this time, the controller 500 controls the on-off valves on both of the communication pipes to be in an open state. It is necessary to use two communication pipes jointly to adjust to cope with the large circulation demand of the alkali solution, so as to ensure the stability of the water electrolysis hydrogen production system 10.

[0083] In another embodiment, referring to Figure 2 , the communication pipe has three, when Q min ≤ Q < 0.4Q max , the on-off valve on one of the communication pipes is in an open state, and the on-off valves on the other two communication pipes are in a closed state; when 0.4Q max ≤ Q ≤ 0.7Q max , the on-off valves on two of the communication pipes are in an open state, and the on-off valve on the remaining one communication pipe is in a closed state; when 0.7Q max ≤ Q ≤ Q max , the on-off valves on all three communication pipes are in an open state.

[0084] In order to control more finely, three communication pipes of the same specification can be provided, and the range of the actual circulation amount of the alkali solution of the water electrolysis hydrogen production system 10 is divided into smaller ranges, and the water electrolysis hydrogen production system 10 can open the on-off valves on different numbers of communication pipes according to the working conditions of the water electrolysis hydrogen production system 10.

[0085] When Q min ≤ Q < 0.4Q max , the flow of the caustic is slow, and the liquid level changes little. At this time, the controller 500 controls the on-off valve on one of the communication pipes to be in an open state, and the on-off valves on the other two communication pipes to be in a closed state. The caustic liquid levels of the hydrogen-side separator 210 and the oxygen-side separator 220 are connected only through one communication pipe to achieve the regulation of the caustic liquid level balance of the two, and to avoid instability caused by large flow.

[0086] When 0.4Q max ≤ Q ≤ 0.7Q max , the flow of the caustic is moderate, and the liquid level changes greatly. At this time, the controller 500 controls the on-off valves on two of the communication pipes to be in an open state, and the on-off valve on the other communication pipe to be in a closed state. Two communication pipes need to be used simultaneously for joint regulation to cope with the greater caustic circulation demand, to ensure the stability of the water electrolysis hydrogen production system 10.

[0087] When 0.7Q max ≤ Q ≤ Q max , the flow of the caustic is fast, and the liquid level changes dramatically. At this time, the controller 500 controls the on-off valves on all three communication pipes to be in an open state. Three communication pipes need to be used simultaneously for joint regulation to cope with the greater caustic circulation demand, to ensure the stability of the water electrolysis hydrogen production system 10.

[0088] In an embodiment, please refer to Figure 1 and Figure 2 , a booster pump 700 and a heat exchanger 800 are provided on the return flow path P, and the flow meter 600 is arranged between the heat exchanger 800 and the return port 130.

[0089] The booster pump 700 is installed on the return flow path P to increase the circulating pressure of the caustic, avoid the situation that the caustic may be insufficient in circulating power due to pipeline resistance or changes in the load of the water electrolysis hydrogen production system 10, and ensure that the caustic can smoothly return from the hydrogen-side separator 210 and the oxygen-side separator 220 to the return port 130 of the electrolytic cell 100. Heat is generated during the water electrolysis process, which may cause the temperature of the caustic in the hydrogen-side separator 210 and the oxygen-side separator 220 to rise. The heat exchanger 800 is installed on the return flow path P to cool the temperature of the caustic, so that the caustic returning to the electrolytic cell 100 is as close as possible to the temperature of the caustic in the electrolytic cell 100, to ensure the stable operation of the electrolytic cell 100. The flow meter 600 is arranged between the heat exchanger 800 and the return port 130 to monitor the actual operating circulation amount of the caustic after being treated by the heat exchanger 800, to ensure that the flow meter 600 measures the caustic flow that has been temperature-regulated, thereby providing more accurate data, and at the same time avoiding damage to the flow meter 600 caused by high-temperature caustic.

[0090] In an embodiment, referring to Figure 3 , the water electrolysis hydrogen production system 10 comprises a plurality of electrolytic cells 100, which share the same hydrogen-side separator 210 and the same oxygen-side separator 220.

[0091] The plurality of electrolytic cells 100 operate simultaneously, each generating hydrogen and oxygen, and delivering the hydrogen-alkali gas-liquid mixture to the hydrogen-side separator 210 through the respective hydrogen-side electrolytic product outlet 110, and delivering the oxygen-alkali gas-liquid mixture to the oxygen-side separator 220 through the respective oxygen-side electrolytic product outlet 120. The flow rate of the alkali solution flowing into the plurality of electrolytic cells 100 through the backflow port 130 of the water electrolysis hydrogen production system 10 is different under different working conditions. As the flow rate of the alkali solution increases, it is more beneficial to the stability of the operation of the water electrolysis hydrogen production system 10 and to the improvement of the purity of the gas if the diameter of the connecting pipe is larger or the length of the connecting pipe is shorter. The opening and closing of the first connecting pipe 310 and the second connecting pipe 320 are controlled according to the total flow rate of the alkali solution flowing back into the backflow port 130 of the plurality of electrolytic cells 100, and at least one of the first on-off valve 410 and the second on-off valve 420 is ensured to be in an open state.

[0092] The plurality of electrolytic cells 100 share the same hydrogen-side separator 210 and the same oxygen-side separator 220, which reduces the number of separators required, improves the utilization rate of the equipment, and thus reduces the manufacturing cost. At the same time, the complexity of the water electrolysis hydrogen production system 10 is reduced, which facilitates centralized management and maintenance, and the operating personnel only need to focus on a small number of key equipment (such as the hydrogen-side separator 210, the oxygen-side separator 220, the controller 500, etc.), which greatly simplifies the operation process. By increasing the number of electrolytic cells 100 and appropriately adjusting the capacity of the separators, it is easy to expand to a configuration of more electrolytic cells 100, which can meet the demand for larger-scale hydrogen production.

[0093] The above only describes exemplary embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made by using the contents of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A hydrogen production system by water electrolysis, characterized by, The water electrolysis hydrogen production system comprises: an electrolytic cell having a hydrogen-side electrolysis product outlet and an oxygen-side electrolysis product outlet; a hydrogen-side separator in communication with the hydrogen-side electrolysis product outlet; an oxygen-side separator in communication with the oxygen-side electrolysis product outlet; a plurality of communication pipes, each of which is provided with a switch valve, and the hydrogen-side separator and the oxygen-side separator are connected through the plurality of parallel communication pipes.

2. The water electrolysis hydrogen generation system of claim 1, wherein, The water electrolysis hydrogen production system further comprises a controller electrically connected with the switch valves, and the controller is used to control the switch valves to be in an open state or a closed state.

3. The water electrolysis hydrogen generation system of claim 2, wherein, The communication pipes are configured as a first communication pipe and a second communication pipe, the first communication pipe is provided with a first switch valve, the second communication pipe is provided with a second switch valve, the diameter of the first communication pipe is greater than that of the second communication pipe, and / or the length of the first communication pipe is less than that of the second communication pipe.

4. The water electrolysis hydrogen generation system of claim 3, wherein, The controller is electrically connected with a power supply of the electrolytic cell, and the controller is used to control the first switch valve and the second switch valve to be in an open state or a closed state according to an operating parameter of the electrolytic cell.

5. The water electrolysis hydrogen generation system of claim 4, wherein, The defined parameter W is a ratio of an actual operating power of the electrolytic cell to a rated power, when 30%≤W<50%, the controller is used to control the first switch valve to be in a closed state and the second switch valve to be in an open state; when 50%≤W≤110%, the controller is used to control the first switch valve to be in an open state and the second switch valve to be in a closed state.

6. The water electrolysis hydrogen generation system of claim 3, wherein, The electrolytic cell further has a liquid return port, the hydrogen-side separator and the oxygen-side separator are in communication with the liquid return port through a liquid return flow path, the water electrolysis hydrogen production system further comprises a flow meter arranged on the liquid return flow path, the flow meter is used to obtain an actual operating circulation amount of lye on the liquid return flow path, and the controller is electrically connected with the flow meter.

7. The water electrolysis hydrogen generation system of claim 6, wherein, The actual running circulation quantity is Q, the minimum safe circulation quantity of the lye on the liquid return flow path is Q min , and the maximum allowable circulation quantity is Q max , When Q min ≤ Q < 0.5Q max the controller is configured to control the first on-off valve to be in a closed state and the second on-off valve to be in an open state. when 0.5Q max ≤ Q ≤ Q max the controller is configured to control the first on-off valve to be in an open state and the second on-off valve to be in a closed state.

8. The water electrolysis hydrogen generation system of claim 6, wherein, The actual running circulation quantity is Q, the minimum safe circulation quantity of the lye on the liquid return flow path is Q min , and the maximum allowed circulation quantity is Q max . When Q min ≤ Q < 0.4Q max the controller is configured to control the first on-off valve to be in a closed state and the second on-off valve to be in an open state. when 0.4Q max ≤ Q < 0.6Q max the controller is configured to control the first on-off valve to be in an open state and the second on-off valve to be in a closed state. when 0.6Q max ≤ Q ≤ Q max the controller is configured to control the first and second on-off valves to be in an open state.

9. The water electrolysis hydrogen generation system of claim 2, wherein, The electrolytic cell also has a liquid return port, the hydrogen side separator and the oxygen side separator are communicated with the liquid return port through a liquid return flow path, the water electrolysis hydrogen production system also comprises a flow meter arranged on the liquid return flow path, the flow meter is used to obtain an actual operation circulation amount of the lye on the liquid return flow path, the controller is electrically connected with the flow meter, the actual operation circulation amount is Q, a minimum safety circulation amount of the lye on the liquid return flow path is Q min , and a maximum allowable circulation amount is Q max ; the diameters and lengths of the plurality of communication pipes are the same.

10. The water electrolysis hydrogen generation system of claim 9, wherein, The communication pipes have two, when Q min ≤Q<0.5Q max , one of the communication pipes is in the open state, and the other is in the closed state; when 0.5Q max ≤Q≤Q max , both of the communication pipes are in the open state. or, the communication pipes are three, when Q min ≤ Q < 0.4Q max , the switch valve on one of the communication pipes is in the open state, and the switch valves on the other two communication pipes are in the closed state; when 0.4Q max ≤ Q ≤ 0.7Q max , the switch valves on two of the communication pipes are in the open state, and the switch valve on the other communication pipe is in the closed state; when 0.7Q max ≤ Q ≤ Q max , the switch valves on all of the communication pipes are in the open state.

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