Proton exchange membrane water electrolysis hydrogen production system

Abstract

The utility model provides a proton exchange membrane water electrolysis hydrogen production system. The system comprises an electrolytic bath, a pure water tank, a hydrogen storage tank and a gas-liquid separator, the electrolytic bath comprises an oxygen side outlet and a hydrogen side outlet; the oxygen side outlet is communicated with the pure water tank through an oxygen side outlet pipeline; the hydrogen side outlet is communicated with the gas-liquid separator through a hydrogen side outlet pipeline; the gas-liquid separator comprises a gas outlet and a liquid outlet; the gas outlet is communicated with the hydrogen storage tank through a gas separation pipeline; the liquid outlet is communicated with the pure water tank through a liquid separation pipeline, or the liquid outlet is communicated with an oxygen side outlet pipeline through the liquid separation pipeline; and a buffer water tank is arranged on the liquid separation pipeline. According to the utility model, the effective separation of hydrogen and water is realized, the influence on the stability of the system caused by the impact of the separated water on the system is avoided, the utilization rate of water for electrolysis is also improved, and the cost is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of electrolytic hydrogen production, in particular to a proton exchange membrane water electrolytic hydrogen production system. Background Art

[0002] In the field of electrolytic hydrogen production technology, the main technical routes include alkaline water electrolysis, proton exchange membrane water electrolysis and high-temperature solid oxide water electrolysis. Among them, proton exchange membrane water electrolysis has the characteristics of high operating current density, low energy consumption and high hydrogen production pressure, and is considered to be a suitable solution for water electrolysis hydrogen production. In particular, its high hydrogen production pressure puts forward higher requirements on the hydrogen production system, including the pressure resistance level of various pipes, valves, flow sensors, temperature sensors, pressure sensors, etc., as well as the system's processes and strategies. In particular, the hydrogen produced in the high-pressure hydrogen production process is mixed with a large amount of water, and the separated water needs to be recycled. The current gas-liquid separation method can only achieve simple separation, but there is a lack of supporting solutions for the large amount of separated water. When the amount of water is large, it will cause an impact on the hydrogen production system and affect the normal operation of components (such as sensors) in the system. Therefore, a stable and efficient gas-liquid separation solution is needed. Utility Model Content

[0003] The technical problem to be solved by the utility model is to overcome the defect in the prior art that a large amount of water separated from gas and liquid during high-pressure hydrogenation causes impact on the system and affects the normal operation of components in the system, and to provide a proton exchange membrane water electrolysis hydrogen production system.

[0004] The utility model solves the above technical problems through the following technical solutions:

[0005] The utility model discloses a proton exchange membrane water electrolysis hydrogen production system, which comprises: an electrolytic cell, a pure water tank, a hydrogen storage tank and a gas-liquid separator;

[0006] The electrolyzer comprises an oxygen side outlet and a hydrogen side outlet;

[0007] The oxygen side outlet is connected to the pure water tank through an oxygen side outlet pipeline;

[0008] The hydrogen side outlet is connected to the gas-liquid separator through a hydrogen side outlet pipeline;

[0009] The gas-liquid separator includes a gas outlet and a liquid outlet; the gas outlet is connected to the hydrogen storage tank through a gas separation pipeline; the liquid outlet is connected to the pure water tank through a liquid separation pipeline, or the liquid outlet is connected to the oxygen side outlet pipeline through a liquid separation pipeline;

[0010] The liquid separation pipeline is provided with a buffer water tank;

[0011] The gas-liquid separator is used to separate the gas and liquid from the hydrogen side outlet pipeline;

[0012] The buffer water tank is used to collect the liquid generated by the gas-liquid separator.

[0013] Optionally, the buffer water tank is provided with a first liquid level gauge, and the first liquid level gauge is used to monitor the liquid level of the buffer water tank.

[0014] Optionally, a coil is further provided on the liquid separation pipeline; the coil is connected to the water outlet of the buffer water tank.

[0015] Optionally, if the liquid outlet is connected to the oxygen side outlet pipeline through a liquid separation pipeline and there is a tee pipe, a first check valve is provided between the tee pipe and the oxygen side outlet in the oxygen side outlet pipeline; the first check valve is used to prevent the gas-liquid mixture in the pipeline from flowing back to the oxygen side outlet;

[0016] and / or,

[0017] A second check valve is provided on the hydrogen side outlet pipeline; the second check valve is used to prevent the gas-liquid mixture in the pipeline from flowing back to the hydrogen side outlet.

[0018] Optionally, if the liquid outlet is connected to the oxygen side outlet pipeline through a liquid separation pipeline and there is a tee, a first back pressure valve is provided between the tee in the oxygen side outlet pipeline and the oxygen side outlet; the first back pressure valve is used to adjust the gas pressure of the positive electrode side chamber of the electrolytic cell;

[0019] and / or,

[0020] The gas separation pipeline is provided with a second back pressure valve; the second back pressure valve is used to adjust the gas pressure of the negative electrode side chamber of the electrolytic cell.

[0021] Optionally, the electrolyzer comprises an oxygen side inlet and a hydrogen side inlet;

[0022] The oxygen side inlet is connected to the pure water tank through an oxygen side inlet pipeline;

[0023] The hydrogen side inlet is connected to the pure water tank through a hydrogen side inlet pipeline; a water inlet valve is arranged on the hydrogen side inlet pipeline.

[0024] Optionally, the pure water tank is further provided with a second liquid level gauge, and the second liquid level gauge is used to monitor the liquid level of the pure water tank.

[0025] Optionally, the pure water tank is further provided with a conductivity meter, and the conductivity meter is used to monitor the conductivity of the liquid in the pure water tank.

[0026] Optionally, the oxygen side outlet pipeline is provided with a first concentration meter, and the first concentration meter is used to monitor the hydrogen concentration;

[0027] and / or,

[0028] The hydrogen side outlet pipeline is provided with a second concentration meter, and the second concentration meter is used to monitor the oxygen concentration.

[0029] Optionally, the pure water tank is provided with a temperature sensor.

[0030] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present utility model.

[0031] The positive progress of the utility model is that after the mixture of water and hydrogen discharged from the hydrogen side outlet is separated by the gas-liquid separator, the hydrogen is loaded into the hydrogen storage tank through the gas separation pipeline and the liquid separation pipeline respectively, and the water is recycled to the pure water tank after passing through the buffer water tank for reuse. On the one hand, the effective separation of hydrogen and water is achieved to avoid the impact of the separated water on the system affecting the stability of the system, and on the other hand, the utilization rate of water used for electrolysis is improved, saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of a proton exchange membrane water electrolysis hydrogen production system provided for an exemplary embodiment of the utility model. DETAILED DESCRIPTION

[0033] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation modes described herein are only used to illustrate and explain the present invention, and the protection scope of the present invention is not limited to the specific implementation modes described below.

[0034] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "formed", "installed", "provided with", "set", "connected" and the like should be understood in a broad sense, for example, the connection can be a direct connection, or an indirect connection through an intermediate medium, a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate connector, or it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0035] Figure 1A schematic diagram of a proton exchange membrane water electrolysis hydrogen production system provided for an exemplary embodiment of the utility model. The proton exchange membrane water electrolysis hydrogen production system includes: an electrolyzer 7, a pure water tank 2, a hydrogen storage tank 12 and a gas-liquid separator 8. Among them, the electrolyzer 7 includes an oxygen side outlet 71 and a hydrogen side outlet 72; the oxygen side outlet 71 is connected to the pure water tank 2 through an oxygen side outlet pipeline 711; the hydrogen side outlet 72 is connected to the gas-liquid separator 8 through a hydrogen side outlet pipeline 721; the gas-liquid separator 8 includes a gas separation outlet 81 and a liquid separation outlet 82; the gas separation outlet 81 is connected to the hydrogen storage tank 12 through a gas separation pipeline 81; the liquid separation outlet 82 is connected to the pure water tank 2 through a liquid separation pipeline 82; a buffer water tank 9 is provided on the liquid separation pipeline 82; the gas-liquid separator 8 is used to separate the gas and liquid from the hydrogen side outlet pipeline 721; the buffer water tank 9 is used to collect the liquid produced by the gas-liquid separator 8.

[0036] In one embodiment, based on the above embodiment, the liquid separation outlet 82 can also be connected to the oxygen side outlet pipeline 711 through the liquid separation pipeline 82.

[0037] In this embodiment, the electrolyzer is an electrolyzer based on a proton exchange membrane (PEM). It can be understood by those skilled in the art that the PEM divides the electrolyzer into two parts, namely, an oxygen side chamber and a hydrogen side chamber. In the process of electrolyzing water, the oxygen side chamber will produce oxygen, and the hydrogen side chamber will produce hydrogen. The main purpose of the system shown in the present disclosure is to collect hydrogen. Specifically, if the mixture (generally hydrogen and water) in the hydrogen side outlet pipeline 721 flows into the gas-liquid separator 8 during the process of electrolyzing water to produce hydrogen, the hydrogen and water are automatically separated under the action of centrifugal force and gravity: on the one hand, hydrogen continues to flow out from the gas separation outlet 81 based on the pressure in the pipeline, and hydrogen is poured into the hydrogen storage tank 12 through the gas separation pipeline 81. This process basically realizes the separation of hydrogen and water, as well as the storage of hydrogen; on the other hand, under the action of gravity, the water will drop and flow into the buffer water tank 9 through the liquid separation pipeline 82. This process basically realizes the separation of water and hydrogen, as well as the collection of water.

[0038] In the above embodiment, when water descends under the action of gravity and flows into the buffer water tank 9 through the liquid separation pipeline 82, a large amount of water will first flow into the buffer water tank 9, and the buffer water tank 9 will perform a preliminary storage of the collected water instead of directly flowing into the downstream pipeline through the separation pipeline 82. Therefore, oscillation of the downstream pipeline and various instruments (such as sensors) arranged on the downstream pipeline can be avoided.

[0039] It should be understood that oxygen, as a product of water electrolysis, can theoretically also be collected. The gas-liquid separation method thereof can refer to the gas-liquid separation method of hydrogen mentioned above, which will not be elaborated here.

[0040] In one embodiment, the buffer water tank 9 is provided with a first liquid level meter 91 , and the first liquid level meter 91 is used to monitor the liquid level of the buffer water tank 9 .

[0041] It should be understood that the liquid level gauges involved in the present disclosure (including but not limited to the first liquid level gauge 91 and the second liquid level gauge 21) are used to monitor the liquid level conditions. The types of liquid level gauges include but are not limited to the following types: magnetic flap level gauge, float level gauge, steel belt level gauge, radar level gauge, magnetostrictive level gauge, radio frequency admittance level gauge, tuning fork level gauge, glass plate / glass tube level gauge, static pressure level gauge, pressure level transmitter, capacitive level gauge, intelligent electric float level gauge, buoy level gauge, float level transmitter, electric contact level gauge, magnetic sensitive two-color electronic level gauge, external measurement level gauge, static pressure level gauge, ultrasonic level gauge, differential pressure level gauge (double flange level gauge), and the liquid level gauge can be set at different positions of the water tank (pure water tank 2 and buffer water tank 9) according to actual needs and working principles.

[0042] In addition, the proton exchange membrane water electrolysis hydrogen production system also includes a controller, which is electrically connected to the control components and the collection / processing components in the proton exchange membrane water electrolysis hydrogen production system, and the controller is used to control the components and collect / process the data of the components. The control components include at least one of the following: a rehydration pump 1, a circulation pump 3, a filter 4, a heat exchanger 5, a deionizer 6, an electrolyzer 7, a water inlet valve 75, a gas-liquid separator 8, a solenoid valve 10, a first flame arrester 131, a second flame arrester 132, a third flame arrester 133, a first check valve 141, a second check valve 142, a first back pressure valve 151, and a second back pressure valve 152. The collection / processing components include at least one of the following: a second liquid level meter 21, a conductivity meter 22, and a first liquid level meter 91.

[0043] In this embodiment, when the first liquid level meter 91 monitors that the liquid level of the buffer water tank 9 is lower than or equal to the first liquid level threshold, the controller controls the solenoid valve 10 to be completely closed to store liquid in the buffer water tank 9; when the first liquid level meter 91 monitors that the liquid level of the buffer water tank 9 is higher than or equal to the second liquid level threshold, the controller controls the solenoid valve 10 to be opened to discharge liquid from the buffer water tank 9. Based on the above operation, the liquid level of the buffer water tank 9 can be always maintained between the first liquid level threshold and the second liquid level threshold. It should be understood that the first liquid level threshold and the second liquid level threshold can be adjusted according to actual needs. For example, the first liquid level threshold is set to 20% of the total water level of the buffer water tank 9, and the second liquid level threshold is set to 80% of the total water level of the buffer water tank 9, so that the liquid level of the buffer water tank 9 can always be maintained between 20% and 80% of the total water level of the buffer water tank 9. The advantage of this is that, on the one hand, when the amount of water is large, the impact of drainage on various instruments in the subsequent pipeline can be reduced, and on the other hand, the water collected in the buffer water tank 9 can be uniformly discharged when it accumulates to a certain extent, rather than continuously discharged. This reduces the operating energy consumption of relevant components in the system. For example, when the buffer water tank 9 is storing liquid, the energy consumption of the sensor on the downstream pipeline (such as the separation pipeline) of the buffer water tank 9 is maintained at a low level.

[0044] In the process of storing or discharging liquid in the buffer water tank 9, the liquid storage or liquid discharge of the buffer water tank 9 may be linked with the solenoid valve 10. The solenoid valve 10 can be fully closed to achieve liquid storage, and the solenoid valve 10 can be opened to achieve liquid discharge. The specific opening degree can be adjusted according to actual needs. When the buffer water tank 9 stores liquid, the solenoid valve 10 is fully closed. When the buffer water tank 9 discharges liquid, the solenoid valve 10 can be opened, and the flow rate of liquid discharge can be adjusted by adjusting the opening degree of the solenoid valve 10.

[0045] In one embodiment, a coil 11 is further provided on the separation pipeline 82 ; the coil 11 is connected to the water outlet 92 of the buffer water tank 9 .

[0046] In this embodiment, if the buffer water tank 9 discharges liquid, the water collected in the buffer water tank 9 will flow into the pure water tank 2 after passing through the coil 11; or the coil 11 is connected to the oxygen side outlet pipeline 711, and merges with the water in the oxygen side outlet pipeline 711 before flowing into the pure water tank 2. The advantages of this are that, on the one hand, the coil 11 can fully realize heat exchange with the outside, for example, dissipate heat from the water in the coil 11; on the other hand, the flow of water in the coil 11 can reduce the kinetic energy of the water, avoiding the impact force on various instruments in the subsequent pipelines when the water volume is large.

[0047] In one embodiment, if the liquid separation outlet 82 is connected to the oxygen side outlet pipeline 711 through the liquid separation pipeline 82 and there is a tee, a first check valve 141 is provided between the tee in the oxygen side outlet pipeline 711 and the oxygen side outlet 71; the first check valve 141 is used to prevent the gas-liquid mixture in the pipeline from flowing back to the oxygen side outlet 71.

[0048] It should be understood that the three-way pipe in the present disclosure is a pipe joint with three openings, which should be designated as two inlets and one outlet in the present disclosure, that is, the liquid separation pipeline 82 is connected to one of the inlets (the first inlet), and the other inlet (the second inlet) and the outlet are arranged on the oxygen side outlet pipeline 711, the second inlet is connected to the oxygen side outlet 71 through the oxygen side outlet pipeline 711, and the outlet is connected to the pure water tank 2 through the oxygen side outlet pipeline 711, which plays the role of a junction hub, that is, the liquid separation pipeline 82 and the oxygen side outlet pipeline 711 merge in the three-way pipe and are connected to the pure water tank 2. The description of the three-way pipe will not be repeated later.

[0049] In this embodiment, it should be understood that in the process of preparing hydrogen under high pressure, due to the connectivity between the pipelines, backflow of the pipelines may occur under high pressure. Therefore, the purpose of installing a check valve is to ensure that the gas-liquid mixture from the oxygen side outlet pipeline 711 flows back into the electrolytic cell 7, thereby protecting the electrolytic cell 7.

[0050] In one embodiment, a second check valve 142 is disposed on the hydrogen-side outlet pipeline 721 ; the second check valve 142 is used to prevent the gas-liquid mixture in the pipeline from flowing back to the hydrogen-side outlet 72 .

[0051] In this embodiment, it should be understood that in the process of preparing hydrogen under high pressure, due to the connectivity between the pipelines, backflow of the pipelines may occur under high pressure. Therefore, the purpose of installing a check valve is to ensure that the gas-liquid mixture from the hydrogen side outlet pipeline 721 flows back into the electrolytic cell 7, thereby protecting the electrolytic cell 7.

[0052] In one embodiment, if the liquid separation outlet 82 is connected to the oxygen side outlet pipeline 711 through the liquid separation pipeline 82 and there is a tee, a first check valve 141 is provided between the tee in the oxygen side outlet pipeline 711 and the oxygen side outlet 71; the first check valve 141 is used to prevent the gas-liquid mixture in the pipeline from flowing back to the oxygen side outlet 71; a second check valve 142 is provided on the hydrogen side outlet pipeline 721; the second check valve 142 is used to prevent the gas-liquid mixture in the pipeline from flowing back to the hydrogen side outlet 72.

[0053] In this embodiment, it should be understood that in the process of preparing hydrogen under high pressure, due to the connectivity between the pipelines, backflow of the pipelines may occur under high pressure. Therefore, the purpose of installing a check valve is to ensure that the gas-liquid mixture from the oxygen side outlet pipeline 711 and the hydrogen side outlet pipeline 721 flows back into the electrolytic cell 7, thereby protecting the electrolytic cell 7.

[0054] In one embodiment, if the liquid separation outlet 82 is connected to the oxygen side outlet pipeline 711 through the liquid separation pipeline 82 and there is a tee, a first back pressure valve 151 is provided between the tee in the oxygen side outlet pipeline 711 and the oxygen side outlet 71; the first back pressure valve 151 is used to adjust the gas pressure in the oxygen side chamber of the electrolytic cell 7.

[0055] In this embodiment, it should be understood that in the process of preparing hydrogen under high pressure, the control of pressure is very critical, especially when the hydrogen produced is expected to reach a preset pressure, so it is necessary to hold the pressure through a back pressure valve, that is, after the back pressure valve is set, the pressure of hydrogen will gradually increase as hydrogen is produced. Similarly, for the preparation of oxygen, a back pressure valve can also be used to hold the pressure, that is, after the first back pressure valve 151 is set, the air pressure in the oxygen side chamber of the electrolyzer 7 will gradually increase as oxygen is produced.

[0056] It should be understood that in the present disclosure, regarding the back pressure valve setting value, it may optionally refer to the setting of the pressure threshold, that is, if the fluid pressure does not reach the pressure threshold, pressure build-up will occur, causing the inlet pressure to rise until it reaches the pressure threshold, and then a passage can be formed, which will not be elaborated in the following text.

[0057] In one embodiment, a second back-pressure valve 152 is provided on the gas separation pipeline 81 ; the second back-pressure valve 152 is used to adjust the gas pressure of the hydrogen-side chamber of the electrolyzer 7 .

[0058] In this embodiment, it should be understood that in the process of preparing hydrogen under high pressure, pressure control is very critical, especially when the hydrogen produced is expected to reach a preset pressure, so it is necessary to hold the pressure through the back pressure valve, that is, when the back pressure valve is set, the pressure of the hydrogen will gradually increase as the hydrogen is produced. That is, when the second back pressure valve 152 is set, the gas pressure in the hydrogen side chamber of the electrolyzer 7 will gradually increase as the hydrogen is produced.

[0059] In one embodiment, if the liquid separation outlet 82 is connected to the oxygen side outlet pipeline 711 through the liquid separation pipeline 82 and there is a tee, a first back pressure valve 151 is provided between the tee in the oxygen side outlet pipeline 711 and the oxygen side outlet 71; the first back pressure valve 151 is used to adjust the gas pressure of the oxygen side chamber of the electrolyzer 7. A second back pressure valve 152 is provided on the gas separation pipeline 81; the second back pressure valve 152 is used to adjust the gas pressure of the hydrogen side chamber of the electrolyzer 7.

[0060] In this embodiment, it should be understood that in the process of preparing hydrogen under high pressure, the control of pressure is very critical, especially when the hydrogen produced is expected to reach a preset pressure, so it is necessary to hold the pressure by adjusting the back pressure valve, and the pressure of hydrogen will gradually increase as the hydrogen is produced. Similarly, for the preparation of oxygen, the back pressure valve can also be used to hold the pressure, that is, when the first back pressure valve 151 is set to a value, the air pressure in the oxygen side chamber of the electrolyzer 7 will gradually increase as the oxygen is produced.

[0061] In one embodiment, the electrolyzer 7 includes an oxygen side inlet 73 and a hydrogen side inlet 74; wherein the oxygen side inlet 73 is connected to the pure water tank 2 through an oxygen side inlet pipeline 731; the hydrogen side inlet 74 is connected to the pure water tank 2 through a hydrogen side inlet pipeline 741; a water inlet valve 75 is provided on the negative electrode inlet pipeline 741, and the water inlet valve 75 is used to control the opening and closing of water flowing into the hydrogen side chamber of the electrolyzer 7. Optionally, the water inlet valve 75 has two working modes, one is an open mode, when in the open mode, water will flow into the hydrogen side chamber of the electrolyzer 7 through the water inlet valve 75; the other is a closed mode, when in the closed mode, the water inlet valve 75 will cut off the water path, and water will not be able to pass through the water inlet valve 75.

[0062] The use scenario in this embodiment can be optionally the use scenario of the pressure equalization system. One feature of the pressure equalization system is that a dual-chamber water inlet method is adopted, that is, the water in the pure water tank 2 is provided with pressure by the circulation pump 3 to press the water into the electrolyzer 7 through two water pipes: one is to press the water into the oxygen side inlet 73 through the oxygen side inlet pipe 731, and the other is to press the water into the hydrogen side inlet 74 through the hydrogen side inlet pipe 741. It should be understood that the direct consequence of the dual-chamber water inlet method is that a large amount of water in the hydrogen side chamber flows out of the hydrogen side outlet 72 along with the hydrogen, which is also the necessity of the present disclosure to perform gas-liquid separation through the gas-liquid separator 8, and the necessity of setting the buffer water tank 9.

[0063] In one embodiment, the method of preparing hydrogen using PEM is a single-chamber water inlet method, that is, the water in the pure water tank 2 is pressurized by the circulation pump 3 to press the water into the electrolyzer 7 through a water pipe: the water is pressed into the oxygen side inlet 73 through the oxygen side inlet pipeline 731.

[0064] Therefore, for the dual-chamber water inlet method or the single-chamber water inlet method, it can be achieved by opening or closing the water inlet valve 75. Among them, when the electrolyzer 7 adopts the single-chamber water inlet method, if the pressure is held, the pressure in the hydrogen side chamber is too high, which will further cause the proton exchange membrane (PEM) to be squeezed and damaged; when the electrolyzer 7 adopts the dual-chamber water inlet method, because the inlet comes from the same water channel, the pressure difference between the hydrogen side chamber and the oxygen side chamber is not large, and the pressure balance on both sides of the PEM can be basically achieved. It can be seen that the dual-chamber water inlet method and the single-chamber water inlet method can be switched by opening or closing the water inlet valve 75, and the pressure balance state can be further adjusted.

[0065] In one embodiment, the pure water tank 2 is further provided with a second liquid level meter 21 , and the second liquid level meter 21 is used to monitor the liquid level of the pure water tank 2 .

[0066] In this embodiment, when the second liquid level meter 21 monitors that the liquid level of the pure water tank 2 is lower than or equal to the third liquid level threshold, the pure water tank 2 is replenished, and the replenishment needs to be coordinated with the start of the replenishment pump 1 to press the water for electrolysis into the pure water tank 2, wherein the water for electrolysis can optionally be deionized water / ultrapure water, which has the characteristics of less impurities and high water purity; when the second liquid level meter 21 monitors that the liquid level of the pure water tank 2 is higher than or equal to the fourth liquid level threshold, the pure water tank 2 stops replenishing the liquid, and stopping the replenishment needs to be coordinated with the stopping of the replenishment pump 1. After the replenishment pump 1 stops running, the water for electrolysis stops entering the pure water tank 2.

[0067] Based on the above operation, the liquid level of the pure water tank 2 can be kept between the third liquid level threshold and the fourth liquid level threshold. It should be understood that the third liquid level threshold and the fourth liquid level threshold can be adjusted according to actual needs. For example, the third liquid level threshold is set to 20% of the total water level of the pure water tank 2, and the fourth liquid level threshold is set to 80% of the total water level of the pure water tank 2, so that the liquid level of the pure water tank 2 can be kept between 20% and 80% of the total water level of the pure water tank 2. The advantage of this is that it can ensure that the pure water tank 2 has sufficient water to provide to the electrolytic cell 7 for electrolysis.

[0068] Optionally, in another specific embodiment, based on any of the above embodiments, the pure water tank 2 is further provided with a conductivity meter 22 , and the conductivity meter 22 is used to monitor the conductivity of the liquid in the pure water tank 2 .

[0069] In this embodiment, when the conductivity meter 22 monitors that the conductivity of the water in the pure water tank 2 is less than or equal to the first conductivity threshold, it means that the water in the pure water tank 2 can be effectively electrolyzed. In this case, the overall operation of the system continues normally, and the conductivity of the water in the pure water tank 2 continues to be monitored; when the conductivity meter 22 monitors that the conductivity of the water in the pure water tank 2 is greater than or equal to the second conductivity threshold, it means that the water in the pure water tank 2 is not suitable for electrolysis. In this case, the system is not suitable to continue. At this time, the operation and maintenance personnel are warned to replace the water for electrolysis based on the conductivity, or the system is stopped and reminded to replace the water for electrolysis. The conductivity of the water in the pure water tank 2 should also be monitored until the conductivity returns to the normal range (less than or equal to the first conductivity threshold). It should be understood that the first conductivity threshold and the second conductivity threshold can be adjusted according to actual needs. For example, the first conductivity threshold is 1μs / cm, and the second conductivity threshold is 5μs / cm. When the conductivity meter 22 monitors that the conductivity of the water in the pure water tank 2 is less than 1μs / cm, it means that the water in the pure water tank 2 can be effectively electrolyzed; when the conductivity meter 22 monitors that the conductivity of the water in the pure water tank 2 is greater than or equal to 1μs / cm, it means that the water in the pure water tank 2 is not suitable for electrolysis. Further judgment can be continued. For example, if the conductivity of the water in the pure water tank 2 is greater than or equal to 1μs / cm, it means that water needs to be changed. If the conductivity of the water in the pure water tank 2 is greater than or equal to 5μs / cm, the shutdown of the electrolytic cell 7 is triggered to protect the electrolysis equipment.

[0070] Optionally, in another specific embodiment, based on any of the above embodiments, further improvements may be made:

[0071] In one embodiment, the oxygen-side outlet pipeline 711 is provided with a first concentration meter, and the first concentration meter is used to monitor the hydrogen concentration.

[0072] In one embodiment, the hydrogen-side outlet pipeline 721 is provided with a second concentration meter, and the second concentration meter is used to monitor the oxygen concentration.

[0073] In one embodiment, the oxygen-side outlet pipeline 711 is provided with a first concentration meter, which is used to monitor the hydrogen concentration. The hydrogen-side outlet pipeline 721 is provided with a second concentration meter, which is used to monitor the oxygen concentration.

[0074] In this embodiment, for example, when the first concentration meter detects that the hydrogen concentration reaches 0.4%, an audible and visual alarm is issued to remind that the hydrogen concentration exceeds the standard. When it reaches 0.8%, the system operation is stopped and the operation and maintenance personnel are reminded to check. For example, when the second concentration meter detects that the oxygen concentration reaches 0.1%, an audible and visual alarm is issued to remind that the oxygen concentration exceeds the standard. When it reaches 0.2%, the system operation is stopped and the operation and maintenance personnel are reminded to check. Similarly, a concentration meter can be installed above the entire system to monitor the concentration of hydrogen and / or oxygen in the entire system environment to ensure that there is no leakage of oxygen and / or hydrogen in the system. It should be understood that the threshold of the concentration meter can be adjusted according to actual needs.

[0075] Optionally, in another specific embodiment, based on any of the above embodiments, the pure water tank 2 is provided with a temperature sensor 16 .

[0076] In this embodiment, it should be understood that heat is generated during the process of electrolysis of water. As the source of water for electrolysis, the pure water tank 2 is crucial to monitor the water temperature.

[0077] Based on any of the above embodiments, a more detailed schematic diagram of a proton exchange membrane water electrolysis hydrogen production system is provided. Figure 1It can be seen that the proton exchange membrane water electrolysis hydrogen production system also includes: a filter 4, a heat exchanger 5, a deionizer 6, a first flame arrester 131, a second flame arrester 132, and a third flame arrester 133. Among them, the heat exchanger 5 is a plate-fin type or shell-and-tube heat exchanger, and the filter 4 can be a resin, metal or reverse osmosis membrane filter; wherein, the pure water tank 2 is provided with a sewage outlet to facilitate the discharge of sediment or other impurities in the pure water tank. In addition, the electrolyzer 7 can be an electrolyzer with pressure bearing capacity or an electrolyzer with a jacket pressure vessel, and because the present system involves a high-pressure PEM process, other components and pipelines involved in the system other than the electrolyzer are designed to withstand high pressure, such as using high-pressure resistant materials and / or high-pressure resistant structures. For example, the gaskets used in the PEM can optionally include: silicone rubber, fluororubber, EPDM rubber, polytetrafluoroethylene and corresponding modified gaskets. A reference value is provided here, for example, the pressure bearing capacity of the hydrogen side chamber of the electrolyzer is designed to be above 30MPa, and other pipelines also involve sealing technology above 30MPa. In order to illustrate the above-mentioned proton exchange membrane water electrolysis hydrogen production system, a specific example is given here: the replenishment pump pumps 60°C pure water into the pure water tank, and monitors the pure water tank through the liquid level meter linkage. When the liquid level is lower than 20% of the total liquid level of the pure water tank, the replenishment pump is started for replenishment, and when the liquid level is higher than 80% of the total liquid level of the pure water tank, the replenishment pump is closed. At the same time, the conductivity meter monitors the conductivity of the water in the pure water tank. When the conductivity is less than 1μs / cm, electrolysis can be carried out. If the conductivity is greater than 1μs / cm (0.1ms / m), the water is changed. If the conductivity is greater than or equal to 5μs / cm, the electrolysis is stopped to protect the electrolysis equipment. Start the circulation pump to pump water into the high-pressure electrolyzer. The water inlet valve on the hydrogen side inlet pipeline of the electrolyzer controls the single-chamber water inlet or double-chamber water inlet to achieve the switching between the differential pressure and the equalizing pressure system. The circulation pump is connected to the filter, heat exchanger, and deionizer in sequence, and then connected to the high-pressure electrolyzer. Temperature, pressure, and flow sensors are installed to monitor water temperature, water pressure, and water flow parameters. Among them, the electrolyzer is connected to a DC power supply for electrolysis reaction, and oxygen and water produced on the oxygen side flow back to the pure water tank for gas-liquid separation, pure water is recycled, and oxygen is exhausted. A hydrogen concentration meter in oxygen (a specific example of the first concentration meter) is installed on the oxygen pipeline to monitor the hydrogen concentration. When the hydrogen concentration reaches 0.4%, an audible and visual alarm is triggered. When the hydrogen concentration reaches 0.8%, the system is stopped. Hydrogen and water are produced on the hydrogen side and enter the gas-liquid separator for gas-liquid separation. The upper hydrogen enters the hydrogen storage tank or is post-processed. A hydrogen concentration meter in oxygen (a specific example of the second concentration meter) is installed on the hydrogen pipeline to monitor the oxygen concentration. When the oxygen concentration reaches 0.1%, an audible and visual alarm is triggered. When the oxygen concentration reaches 0.2%, the system is stopped. Pure water on the lower side of the gas-liquid separator enters the buffer water tank, and the liquid level gauge on the buffer water tank is linked to the solenoid valve to control water storage or drainage. When the liquid level in the buffer water tank is higher than 80% of the total liquid level, the solenoid valve is opened and enters the pure water tank through the coil. When the liquid level in the buffer water tank is lower than 20% of the total liquid level, the solenoid valve is closed.In addition, a hydrogen alarm is installed above the entire system to monitor the hydrogen concentration in the entire system environment. When the hydrogen concentration reaches 0.4%, an audible and visual alarm is sounded, and when the hydrogen concentration reaches 0.8%, the system is stopped. Similarly, in order to monitor the oxygen concentration in the entire system environment, an oxygen alarm can also be installed above the entire system, and the alarm threshold can be set according to actual needs. Among them, the hydrogen alarm can alarm based on the detection results of the oxygen-in-oxygen concentration meter, and the oxygen alarm can alarm based on the detection results of the oxygen-in-hydrogen concentration meter.

[0078] On this basis, the system installs back pressure valves on the two output branches of the electrolyzer to adjust the system working pressure. Flame arresters are installed at the ends of the oxygen side outlet pipeline and the hydrogen side outlet pipeline to prevent explosion and combustion. Three-way valves are installed at the outlet end of the pure water tank, before the flame arrester of the hydrogen side outlet pipeline, and before the oxygen side outlet pipeline enters the pure water tank to facilitate nitrogen purging.

[0079] Although the specific implementations of the utility model are described above, those skilled in the art should understand that this is only an example, and the protection scope of the utility model is defined by the attached claims. Those skilled in the art can make various changes or modifications to these implementations without departing from the principle and essence of the utility model, but these changes and modifications fall within the protection scope of the utility model.

Claims

1. A proton exchange membrane water electrolysis hydrogen production system, characterized in that: The proton exchange membrane water electrolysis hydrogen production system comprises: an electrolyzer, a pure water tank, a hydrogen storage tank and a gas-liquid separator; The electrolyzer comprises an oxygen side outlet and a hydrogen side outlet; The oxygen side outlet is connected to the pure water tank through an oxygen side outlet pipeline; The hydrogen side outlet is connected to the gas-liquid separator through a hydrogen side outlet pipeline; The gas-liquid separator includes a gas outlet and a liquid outlet; the gas outlet is connected to the hydrogen storage tank through a gas separation pipeline; the liquid outlet is connected to the pure water tank through a liquid separation pipeline, or the liquid outlet is connected to the oxygen side outlet pipeline through a liquid separation pipeline; The liquid separation pipeline is provided with a buffer water tank; The gas-liquid separator is used to separate the gas and liquid from the hydrogen side outlet pipeline; The buffer water tank is used to collect the liquid generated by the gas-liquid separator.

2. The proton exchange membrane water electrolysis hydrogen production system according to claim 1, characterized in that: The buffer water tank is provided with a first liquid level gauge, and the first liquid level gauge is used to monitor the liquid level of the buffer water tank.

3. The proton exchange membrane water electrolysis hydrogen production system according to claim 1, characterized in that: The liquid separation pipeline is also provided with a coil; the coil is communicated with the water outlet of the buffer water tank.

4. The proton exchange membrane water electrolysis hydrogen production system according to claim 1, characterized in that: If the liquid outlet is connected to the oxygen side outlet pipeline through a liquid separation pipeline and there is a tee pipe, a first check valve is provided between the tee pipe and the oxygen side outlet in the oxygen side outlet pipeline; the first check valve is used to prevent the gas-liquid mixture in the pipeline from flowing back to the oxygen side outlet; and / or, A second check valve is provided on the hydrogen side outlet pipeline; the second check valve is used to prevent the gas-liquid mixture in the pipeline from flowing back to the hydrogen side outlet.

5. The proton exchange membrane water electrolysis hydrogen production system according to claim 1, characterized in that: If the liquid outlet is connected to the oxygen side outlet pipeline through a liquid separation pipeline and there is a tee pipe, a first back pressure valve is provided between the tee pipe and the oxygen side outlet in the oxygen side outlet pipeline; the first back pressure valve is used to adjust the gas pressure of the oxygen side chamber of the electrolyzer; and / or, The gas separation pipeline is provided with a second back pressure valve; the second back pressure valve is used to adjust the gas pressure of the hydrogen side chamber of the electrolyzer.

6. The proton exchange membrane water electrolysis hydrogen production system according to any one of claims 1 to 5, characterized in that: The electrolyzer comprises an oxygen side inlet and a hydrogen side inlet; The oxygen side inlet is connected to the pure water tank through an oxygen side inlet pipeline; The hydrogen side inlet is connected to the pure water tank through a hydrogen side inlet pipeline; a water inlet valve is arranged on the hydrogen side inlet pipeline.

7. The proton exchange membrane water electrolysis hydrogen production system according to any one of claims 1 to 5, characterized in that: A second liquid level gauge is also provided in the pure water tank, and the second liquid level gauge is used to monitor the liquid level of the pure water tank.

8. The proton exchange membrane water electrolysis hydrogen production system according to any one of claims 1 to 5, characterized in that: The pure water tank is also provided with a conductivity meter, and the conductivity meter is used to monitor the conductivity of the liquid in the pure water tank.

9. The proton exchange membrane water electrolysis hydrogen production system according to any one of claims 1 to 5, characterized in that: The oxygen side outlet pipeline is provided with a first concentration meter, and the first concentration meter is used to monitor the hydrogen concentration; and / or, The hydrogen side outlet pipeline is provided with a second concentration meter, and the second concentration meter is used to monitor the oxygen concentration.

10. The proton exchange membrane water electrolysis hydrogen production system according to any one of claims 1 to 5, characterized in that: A temperature sensor is arranged in the pure water tank.

Images