Electrolytic hydrogen production system and control method thereof

Abstract

The application provides an electric hydrogen production system and a control method thereof, and relates to the technical field of safe operation of hydrogen production by water electrolysis. In one aspect, the application provides an electric hydrogen production system, which is provided with a pipe pressure balancing device, and can monitor the current change amount of a PEM electrolytic cell, the actual gas pipe pressure of an oxygen exhaust pipe and a hydrogen exhaust pipe, and the actual liquid level of a gas-liquid separation device in real time. The application adjusts the real-time current of the PEM electrolytic cell to adjust the gas pipe pressure of the pipe through a control center, and adjusts the gas pipe pressure of the pipe through a pipe pressure regulating valve, so that the gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe both meet the safe pressure relationship. In another aspect, the application provides a control method of the electric hydrogen production system, which realizes the safe operation of the electric hydrogen production system through self-checking control, current control, liquid level control and emergency control. The application not only improves the safety of the system, but also ensures the purity and efficiency of the gas, so that the large-capacity PEM electrolytic cell is more reliable and efficient in actual application.

Description

Technical Field

[0001] This invention relates to the field of safe operation technology for hydrogen production by water electrolysis, and in particular to an electrolytic hydrogen production system and its control method. Background Technology

[0002] With the growing demand for low-carbon emission reduction, green hydrogen production technologies have attracted significant attention. Water electrolysis is one of the lowest-carbon emission methods for hydrogen production. Hydrogen has enormous potential for applications in various fields and can effectively reduce greenhouse gas emissions. Proton exchange membrane (PEM) water electrolysis technology represents a direction for green hydrogen production, promoting its integration with renewable energy. During electrolysis, water is decomposed at the anode into oxygen, hydrogen ions, and electrons. Hydrogen ions pass through the proton exchange membrane to the cathode. Electrons flow out from the anode, through the power circuit to the cathode, while the power supply provides the driving force. On the cathode side, two protons and an electron recombine to produce hydrogen gas.

[0003] Currently, the mainstream research direction for improving electro-hydrogen production devices is to balance the pressure on the oxygen and hydrogen sides, thereby ensuring pressure balance in the pipelines on both sides and preventing excessive pressure differences that could lead to mixing of oxygen and hydrogen and potentially causing explosions or other dangerous accidents. Chinese patent "CN116356346A Hydrogen Production System and Control Method for Hydrogen Production System" proposes a method for balancing the pressure on the oxygen and hydrogen sides. This method controls the hydrogen production equipment by setting a first actual pressure, a first actual liquid level, a second actual liquid level, and the actual change in current flowing into the PEM electrolyzer, ensuring the safety of the hydrogen production equipment. This patent employs PID control, negative feedback control, and sliding plate control to control pressure, liquid level, and current, ensuring that the hydrogen production system maintains pressure and liquid level balance on both the oxygen and hydrogen production sides at all times. This prevents drastic changes in hydrogen production that could exceed safety thresholds and cause safety risks to the hydrogen production system.

[0004] Currently, the pressure balancing of water electrolysis hydrogen production units mainly involves balancing the pressure of the oxygen and hydrogen side pipelines in a single PEM electrolyzer. Because the capacity of a single PEM electrolyzer is insufficient, multiple PEM electrolyzers are usually connected in series to form a large-capacity PEM electrolysis unit. In this case, to save on piping materials, the gas pipelines on the hydrogen side of all PEM electrolyzers are connected in parallel before being connected to a main hydrogen pipeline and fed into a hydrogen tank. Similarly, the gas pipelines on the oxygen side are connected in parallel and then connected to a main oxygen pipeline before being fed into an oxygen tank. However, when multiple PEM electrolyzers are operating simultaneously, while ensuring the pressure balance of the hydrogen and oxygen sides of a single PEM electrolyzer, the pressure of the parallel gas pipelines on the oxygen side or hydrogen side of each PEM is not considered to be consistent. Disturbances in a PEM electrolyzer can cause excessively high or low pressures in the hydrogen or oxygen side of the pipeline. This, in turn, can lead to significant pressure differences on the same gas side of different PEM electrolyzers, potentially causing gas backflow and an explosion due to the mixing of oxygen and hydrogen. Maintaining pressure and liquid level balance on both sides of the water electrolysis hydrogen production system during operation is a pressing issue that needs to be addressed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the prior art and, in order to ensure that the multi-electrolyte electrolysis device can operate normally under safe conditions, to provide a hydrogen production system and a control method for the hydrogen production system, so as to maintain the gas pressure balance of different pipelines at all times when the multi-electrolyte water electrolysis hydrogen production system is working.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] On one hand, the present invention provides an electro-hydrogen production system, including a power supply device, a water supply device, a front-end pipe pressure balancing device, a hydrogen production device, a gas-liquid separation device, a rear-end pipe pressure balancing device, a heat conversion device, an oxygen storage device VIII, and a hydrogen storage device;

[0008] One end of the power supply device is connected to the power grid, and the other end is connected to the hydrogen production device through a front-end pipe pressure balancing device to supply power to the electro-hydrogen production system. The hydrogen production device is connected to a gas-liquid separation device to electrolyze water and produce oxygen and hydrogen. The gas-liquid separation device is connected to an oxygen storage device and a hydrogen storage device through a rear-end pipe pressure balancing device to separate the liquid from the oxygen and hydrogen. The oxygen storage device stores the oxygen produced by the hydrogen production device, and the hydrogen storage device stores the hydrogen produced by the hydrogen production device. The front-end pipe pressure balancing device is connected to the power supply device and the hydrogen production device, and the rear-end pipe pressure balancing device is connected to the gas-liquid separation device, the oxygen storage device, and the hydrogen storage device. The front-end and rear-end pipe pressure balancing devices are used to monitor the real-time current changes, actual gas pipe pressure, and actual liquid level of the electro-hydrogen production system, and to control the hydrogen production device and balance the gas pipe pressures of each oxygen and hydrogen exhaust pipe. The water supply device is connected to the hydrogen production device to supply water to the hydrogen production device. The heat conversion device is connected to the hydrogen production device to cool the hydrogen production device and recover waste heat to heat the water in the hydrogen production device.

[0009] Preferably, the power supply device includes a step-down transformer, an inverter, and an electrical switch; one end of the step-down transformer is connected to the power grid, and the other end is connected to the inverter; the inverter is connected to the electrical switch, and the electrical switch is connected to the front-end voltage balancing device.

[0010] Preferably, the water supply device includes a water pump, a water purification device, a purified water tank, a purified water pump, an ion filter, and a temperature controller; the outlet of the water pump is connected to the inlet of the water purification device, the outlet of the water purification device is connected to the inlet of the purified water tank, the outlet of the purified water tank is connected to the inlet of the purified water pump, the outlet of the purified water pump is connected to the inlet of the ion filter, and the outlet of the ion filter is connected to the hydrogen production device via the temperature controller; the water pump provides water to the hydrogen production device, the water purification device purifies the water supplied by the water pump to obtain purified water, and the purified water tank stores the purified water; the purified water pump draws purified water from the purified water tank to supply water to the hydrogen production device, and the conductivity of the purified water flowing into the hydrogen production device is controlled by the ion filter to meet operating requirements; the temperature controller controls the temperature of the purified water entering the hydrogen production device from the water supply device.

[0011] Preferably, the hydrogen production device includes a water pipeline switch and a PEM electrolyzer; the water pipeline switch is connected to the PEM electrolyzer, and each PEM electrolyzer is connected to a gas-liquid separation device.

[0012] Preferably, the gas-liquid separation device includes an oxygen-side gas-liquid separator and a hydrogen-side gas-liquid separator; the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator are respectively connected to the oxygen storage device and the hydrogen storage device through a rear-end pipe pressure balancing device; the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator are used to effectively separate the liquid in the oxygen and hydrogen produced by the PEM electrolyzer in the hydrogen production device.

[0013] Preferably, the front-end pipe pressure balancing device includes a control center, a current sensor, and a current switch; the control center is connected to the current sensor, the current sensor is connected to the current switch, and the current switch is connected to the hydrogen production device; the control center and the current sensor are connected via an electrical signal, the current sensor is used to monitor the real-time current change of each PEM electrolyzer, and the control center controls the switching of the current switch, adjusts the input current value, and controls the liquid level of the gas-liquid separation device.

[0014] Preferably, the back-end pipe pressure balancing device includes an oxygen-side pressure level sensor, a hydrogen-side pressure level sensor, an oxygen exhaust pipe pressure regulating valve, a hydrogen exhaust pipe pressure regulating valve, an oxygen exhaust pipe pressure sensor, a hydrogen exhaust pipe pressure sensor, an oxygen exhaust pipe three-way valve, and a hydrogen exhaust pipe three-way valve. The back-end pipe pressure balancing device is divided into an oxygen side and a hydrogen side. On the oxygen side, the oxygen-side pressure level sensor, the oxygen exhaust pipe pressure regulating valve, and the oxygen exhaust pipe pressure sensor are installed on the gas sub-pipe connecting the oxygen-side gas-liquid separator and the oxygen exhaust pipe three-way valve. The inlet of the oxygen exhaust pipe three-way valve is connected to the oxygen in the gas-liquid separator. The oxygen discharge pipe outlet of the gas-liquid separator is connected to the gas discharge pipe outlet, and the two outlet valves of the oxygen discharge pipe three-way valve are connected to the spare oxygen storage tank and the oxygen dryer in the oxygen storage device. On the hydrogen side, the hydrogen side pressure level sensor, the hydrogen discharge pipe pressure regulating valve, and the hydrogen discharge pipe pressure sensor are installed on the gas sub-pipe connecting the hydrogen side gas-liquid separator and the hydrogen discharge pipe three-way valve in the gas-liquid separator. The inlet valve of the hydrogen discharge pipe three-way valve is connected to the hydrogen discharge pipe outlet of the hydrogen side gas-liquid separator in the gas-liquid separator, and the two outlet valves of the hydrogen discharge pipe three-way valve are connected to the spare hydrogen storage tank and the deaerator in the hydrogen storage device.

[0015] The oxygen-side pressure level sensor, hydrogen-side pressure level sensor, oxygen exhaust pipe pressure regulating valve, hydrogen exhaust pipe pressure regulating valve, oxygen exhaust pipe pressure sensor, hydrogen exhaust pipe pressure sensor, oxygen exhaust pipe three-way valve, and hydrogen exhaust pipe three-way valve are connected to the control center of the front-end pipe pressure balancing device via electrical signals. The oxygen-side pressure level sensor and hydrogen-side pressure level sensor are used to monitor the actual liquid level of the gas-liquid separation device in real time. The oxygen exhaust pipe pressure sensor and hydrogen exhaust pipe pressure sensor are used to monitor the actual gas pipe pressure of the oxygen exhaust pipe and hydrogen exhaust pipe of the PEM electrolyzer in real time. The oxygen exhaust pipe pressure regulating valve... The opening of the valves and the hydrogen discharge pipe pressure regulating valves is controlled by the control center to ensure the liquid level and pressure balance on both sides of the hydrogen production equipment, thereby ensuring the safety of the hydrogen production system. The oxygen discharge pipe three-way valve and the hydrogen discharge pipe three-way valve are used to control the gas flow direction. When a PEM electrolyzer malfunctions, the pressure of the gas pipes of that PEM electrolyzer will change drastically, affecting the pressure of the entire gas pipeline. By adjusting the oxygen discharge pipe three-way valve and the hydrogen discharge pipe three-way valve through the control center, the sub-gas pipeline is disconnected from the main gas pipeline, ensuring that the remaining PEM electrolyzers can continue to operate safely.

[0016] Preferably, the oxygen storage device includes a backup oxygen storage tank, an oxygen dryer, an oxygen buffer, and a regular oxygen storage tank; the inlet of the backup oxygen storage tank is connected to one outlet valve of the three-way valve of the oxygen exhaust pipe, the inlet of the oxygen dryer is connected to the other outlet valve of the three-way valve of the oxygen exhaust pipe, the outlet of the oxygen dryer is connected to the inlet of the oxygen buffer, and the outlet of the oxygen buffer is connected to the inlet of the regular oxygen storage tank; the backup oxygen storage tank is used to temporarily store oxygen during the self-test of the electro-hydrogen production system, the oxygen dryer is used to absorb water vapor in the oxygen separated by the oxygen-side gas-liquid separator, and the oxygen buffer is used to absorb the impact force of the oxygen.

[0017] Preferably, the hydrogen storage device includes a backup hydrogen storage tank, a deoxygenator, a hydrogen dryer, a hydrogen buffer, and a main hydrogen storage tank; the inlet of the backup hydrogen storage tank is connected to one outlet valve of the three-way valve of the hydrogen discharge pipe, the inlet of the deoxygenator is connected to the other outlet valve of the three-way valve of the hydrogen discharge pipe, the outlet of the deoxygenator is connected to the inlet of the hydrogen dryer, the hydrogen dryer is connected to the inlet of the hydrogen buffer, and the outlet of the hydrogen buffer is connected to the inlet of the main hydrogen storage tank; the deoxygenator is used to remove oxygen that may be mixed in the hydrogen, thereby improving the purity of the hydrogen; the hydrogen dryer is used to absorb water vapor in the hydrogen separated by the hydrogen-side gas-liquid separator; and the hydrogen buffer is used to absorb the impact force of the hydrogen.

[0018] On the other hand, a control method for an electro-hydrogen production system includes the following steps:

[0019] Step 1: Perform a self-test of the electro-hydrogen production system using the self-test control method, start the pipe pressure balancing device and introduce a preset current into the PEM electrolyzer, and adjust the pipe pressure regulating valve to balance the gas pipe pressure of the oxygen discharge pipe and hydrogen discharge pipe of the PEM electrolyzer and meet the safe pipe pressure relationship.

[0020] First, all three-way valves for oxygen venting and hydrogen venting are connected to the backup oxygen and hydrogen storage tanks. The oxygen-side pressure level sensor and hydrogen-side pressure level sensor obtain the actual liquid levels of the oxygen-side gas-liquid separator and hydrogen-side gas-liquid separator, and determine whether the actual liquid level is at the preset level. If not, the liquid level is adjusted by the oxygen-side pressure level sensor and hydrogen-side pressure level sensor in the control center. After the preset liquid level is met, the pipe pressure balancing device is started, and a preset current is supplied to all PEM electrolyzers. When the PEM electrolyzers are running smoothly, the pipe pressure balancing device monitors the actual gas pressure of the oxygen venting pipe of each PEM electrolyzer and adjusts the oxygen venting pipe pressure regulating valve and the hydrogen venting pipe pressure regulating valve to ensure that the gas pressure of the oxygen venting pipe and the actual gas pressure of the hydrogen venting pipe of each PEM electrolyzer meet the safe pressure relationship. Then the self-test control of the electro-hydrogen production system is completed. The control center controls the three-way valves for oxygen venting and hydrogen venting to connect to the commonly used oxygen and hydrogen storage tanks.

[0021] Step 2: Start hydrogen production. During the hydrogen production process, determine whether the gas pressure of the oxygen and hydrogen venting pipes of the PEM electrolyzer meets the safe pressure relationship. Adjust the pipe pressure using current control and liquid level control. After the pipe pressure meets the safe pressure relationship, store the oxygen and hydrogen in a conventional oxygen and hydrogen storage device.

[0022] In current control, the oxygen and hydrogen exhaust pipe pressure sensors monitor the actual gas pressure of the oxygen and hydrogen exhaust pipes of each PEM electrolyzer and transmit the data back to the control center. When the actual gas pressure meets the safety pressure relationship, the control center controls the oxygen and hydrogen exhaust pipe three-way valves to connect to the commonly used oxygen and hydrogen storage tanks. When the actual gas pressure does not meet the safety pressure relationship, the control center calculates the actual oxygen and hydrogen production rates of the corresponding PEM electrolyzer through real-time current to obtain the relationship between the real-time current and the actual gas pressure of the oxygen and hydrogen exhaust pipes. The control center uses PID control to change the real-time current input to each PEM electrolyzer within a reasonable hydrogen production efficiency range, controls the gas pressure of the oxygen and hydrogen exhaust pipes based on the real-time current, and simultaneously adjusts the oxygen and hydrogen exhaust pipe pressure regulating valves for auxiliary adjustment to ensure that the gas pressure of the oxygen and hydrogen exhaust pipes meets the safety pressure relationship.

[0023] In liquid level control, the oxygen and hydrogen exhaust pipe pressure sensors acquire the actual gas pressure of the oxygen and hydrogen exhaust pipes in the PEM electrolyzer, while the oxygen-side and hydrogen-side pressure-type liquid level sensors acquire the actual liquid levels of the oxygen-side and hydrogen-side gas-liquid separators in the PEM electrolyzer. When the actual pipe pressure does not meet the safe pressure relationship, the actual liquid level value on the hydrogen side or oxygen side is compared with the preset liquid level. When the difference between the actual liquid level and the preset liquid level is too large, the control center uses the pressure-type liquid level sensor to adjust the liquid level of the oxygen-side and hydrogen-side gas-liquid separators based on the difference between the actual liquid level difference and the preset liquid level difference. The control center also uses the oxygen and hydrogen exhaust pipe pressure regulating valves for auxiliary adjustment, thereby balancing the pipeline pressure so that the gas pressure of both the oxygen and hydrogen exhaust pipes meets the safe pressure relationship.

[0024] Step 3: Set the emergency control mode. When the pipe pressure balancing device detects that the gas pipe pressure of the oxygen or hydrogen venting pipe of the PEM electrolyzer exceeds the preset standard deviation of the pipe pressure, the control center controls the three-way valve to close with the main pipeline and connect with the backup oxygen and hydrogen storage tanks. The input circuit of the PEM electrolyzer is disconnected. The self-test control will be restarted after the maintenance is completed.

[0025] In emergency control mode, when the oxygen venting pipe pressure sensor and the hydrogen venting pipe pressure sensor detect that the gas pressure in the oxygen venting pipe or hydrogen venting pipe of a certain PEM electrolyzer exceeds the preset standard deviation of the pipe pressure, that is, when the gas pressure difference in the oxygen venting pipe or hydrogen venting pipe of the PEM electrolyzer is much greater than the adjustable pipe pressure difference within the safe range, and cannot be adjusted by the second and third control methods, the control center will control the oxygen venting pipe three-way valve and the hydrogen venting pipe three-way valve of the faulty PEM electrolyzer to close them to the main pipeline and connect them to the backup oxygen storage tank and the backup hydrogen storage tank. At this time, the control center controls the current switch of the faulty PEM electrolyzer to disconnect, and the PEM electrolyzer enters maintenance. After the self-test control meets the requirements, the oxygen venting pipe three-way valve and the hydrogen venting pipe three-way valve are reconnected to the main output gas pipeline.

[0026] The beneficial effects of adopting the above technical solution are as follows: In addition to considering the pressure balance of the hydrogen and oxygen sides of a single PEM electrolyzer, the pressure balance of the pipeline on the same side of the gas generated by multiple PEM electrolyzers is also considered. This prevents the pressure difference in the parallel pipeline that may be caused by the different working states of each PEM electrolyzer when multiple electrolyzers are working at the same time, and avoids the danger of backflow causing gas mixing.

[0027] Compared with existing technologies, the technical solution proposed in this invention overcomes the deficiency in large-capacity PEM electrolyzers that did not consider the pressure balance of gas pipelines on the same side. This not only improves system safety but also ensures gas purity and efficiency, making large-capacity PEM electrolyzers more reliable and efficient in practical applications. Through this improvement, this technical solution effectively fills the gap in existing technologies and provides a more complete solution. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a hydrogen production system provided in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the specific structure of a PEM water electrolysis hydrogen production system provided in an embodiment of the present invention;

[0030] Figure 3 This is the main flowchart provided in the embodiments of the present invention;

[0031] Figure 4 This is a self-test flowchart provided in an embodiment of the present invention;

[0032] Figure 5 This is a current control flowchart provided in an embodiment of the present invention;

[0033] Figure 6 This is a flowchart of the liquid level control provided in an embodiment of the present invention;

[0034] In the diagram: 1. Step-down transformer; 2. Inverter; 3. Electrical switch; 4. Water pump; 5. Water purification unit; 6. Purified water tank; 7. Purified water pump; 8. Ion filter; 9. Temperature controller; 10. Control center; 11. Current sensor; 12. Current switch; 13. Water pipeline switch; 14. PEM electrolyzer; 15. Oxygen-side gas-liquid separator; 16. Hydrogen-side gas-liquid separator; 17. Oxygen-side pressure level sensor; 18. Hydrogen-side... 19. Pressure level sensor; 20. Oxygen venting pipe pressure regulating valve; 21. Hydrogen venting pipe pressure regulating valve; 22. Oxygen venting pipe pressure sensor; 23. Hydrogen venting pipe pressure sensor; 24. Oxygen venting pipe three-way valve; 25. Hydrogen venting pipe three-way valve; 26. Spare oxygen storage tank; 27. Oxygen dryer; 28. Oxygen buffer; 29. ​​Standard oxygen storage tank; 30. Spare hydrogen storage tank; 31. Deaerator; 32. Hydrogen dryer; 33. Hydrogen buffer; 34. Standard hydrogen storage tank. Detailed Implementation

[0035] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0036] During water electrolysis, water is decomposed into oxygen, hydrogen ions, and electrons at the anode. Hydrogen ions pass through the proton exchange membrane into the cathode. Electrons flow out from the anode, through the power circuit to the cathode, where the power supply provides the driving force. At the cathode, two protons and an electron recombine to produce hydrogen gas. In multi-cell electrolysis units, to save materials, the hydrogen exhaust pipes from each electrolyzer are ultimately connected into a single pipeline before being transported to the hydrogen storage unit, and the oxygen exhaust pipes are ultimately connected into a single pipeline before being transported to the oxygen storage unit. When there are large fluctuations in the power grid, the gas production may change drastically at any time, resulting in lag in pressure and level control. This can cause pressure and level fluctuations to exceed safety margins, posing a safety risk. Therefore, it is necessary to maintain the same gas pressure in each pipeline to prevent pressure differences between different pipelines from causing hydrogen or oxygen to flow back into the electrolyzer, thus exceeding the safety threshold and posing a safety risk to the hydrogen production system.

[0037] In this example, an electro-hydrogen production system, such as... Figure 1As shown, the system includes a power supply unit I, a water supply unit II, a front-end pipe pressure balancing device III, a hydrogen production unit IV, a gas-liquid separation device V, a rear-end pipe pressure balancing device VI, a heat conversion device VII, an oxygen storage device VIII, and a hydrogen storage device IX. One end of the power supply unit I is connected to the power grid, and the other end is connected to the hydrogen production unit IV via the front-end pipe pressure balancing device III, for supplying power to the electro-hydrogen production system. The hydrogen production unit IV is connected to the gas-liquid separation device V for electrolyzing water to produce oxygen and hydrogen. The gas-liquid separation device V is connected to the oxygen storage device VIII and the hydrogen storage device IX via the rear-end pipe pressure balancing device VI, for separating the liquid from the oxygen and hydrogen. The oxygen storage device VIII stores the oxygen produced by the hydrogen production unit IV. Hydrogen unit IX stores hydrogen produced by hydrogen production unit IV; front-end pipe pressure balancing device III is connected to power supply device I and hydrogen production unit IV, and rear-end pipe pressure balancing device VI is connected to gas-liquid separation device V, oxygen storage device VIII, and hydrogen storage device IX. Front-end pipe pressure balancing device III and rear-end pipe pressure balancing device VI are used to monitor the real-time current change, actual gas pipe pressure, and actual liquid level of the electro-hydrogen production system, and to control hydrogen production unit IV, balancing the gas pipe pressure of each oxygen discharge pipe and hydrogen discharge pipe; water supply device II is connected to hydrogen production unit IV to supply water to hydrogen production unit IV; heat conversion device VII is connected to hydrogen production unit IV to cool hydrogen production unit IV and recover waste heat to supply water heating for hydrogen production unit IV;

[0038] like Figure 2 As shown, the power supply device I includes a step-down transformer 1, an inverter 2, and an electrical switch 3; the water supply device II includes a water pump 4, a water purification device 5, a purified water tank 6, a purified water pump 7, an ion filter 8, and a temperature controller 9; the front-end pipe pressure balancing device III includes a control center 10, a current sensor 11, and a current switch 12; the hydrogen production device IV includes a water pipeline switch 13 and four identical PEM electrolyzers 14; the gas-liquid separation device V includes an oxygen-side gas-liquid separator 15 and a hydrogen-side gas-liquid separator 16; and the rear-end pipe pressure balancing device... VI includes an oxygen-side pressure level sensor 17, a hydrogen-side pressure level sensor 18, an oxygen discharge pipe pressure regulating valve 19, a hydrogen discharge pipe pressure regulating valve 20, an oxygen discharge pipe pressure sensor 21, a hydrogen discharge pipe pressure sensor 22, an oxygen discharge pipe three-way valve 23, and a hydrogen discharge pipe three-way valve 24; the oxygen storage device VIII includes a spare oxygen storage tank 25, an oxygen dryer 26, an oxygen buffer 27, and a commonly used oxygen storage tank 28; the hydrogen storage device IX includes a spare hydrogen storage tank 29, a deaerator 30, a hydrogen dryer 31, a hydrogen buffer 32, and a commonly used hydrogen storage tank 33;

[0039] In the power supply device I, one end of the step-down transformer 1 is connected to the power grid, and the other end is connected to the inverter 2. The inverter 2 is connected to the electric switch 3, and the electric switch 3 is connected to the front-end pipe voltage balancing device III to control the switching of the electric hydrogen production system.

[0040] The outlet of the water pump 4 in the water supply device II is connected to the inlet of the water purification device 5. The outlet of the water purification device 5 is connected to the inlet of the purified water tank 6. The outlet of the purified water tank 6 is connected to the inlet of the purified water pump 7. The outlet of the purified water pump 7 is connected to the inlet of the ion filter 8. The outlet of the ion filter 8 is connected to the water pipe switch 13 in the hydrogen production device IV through the temperature controller 9.

[0041] In the front-end pipe pressure balancing device III, the control center 10 is connected to the current sensor 11, the current sensor 11 is connected to the current switch 12, and the current switch 12 is connected to the PEM electrolyzer 14 in the hydrogen production device IV.

[0042] In the hydrogen production device IV, the water pipeline switch 13 is connected to the PEM electrolyzer 14, and the PEM electrolyzer 14 is connected to the oxygen-side gas-liquid separator 15 and the hydrogen-side gas-liquid separator 16 of the gas-liquid separation device V, respectively; in the gas-liquid separation device V, the oxygen-side gas-liquid separator 15 and the hydrogen-side gas-liquid separator 16 are respectively connected to the oxygen storage device VIII and the hydrogen storage device IX through the rear-end pipe pressure balancing device VI.

[0043] The back-end pipe pressure balancing device VI is divided into an oxygen side and a hydrogen side. On the oxygen side, the oxygen-side pressure level sensor 17, the oxygen exhaust pipe pressure regulating valve 19, and the oxygen exhaust pipe pressure sensor 21 are installed on the gas sub-pipe connecting the oxygen-side gas-liquid separator 15 and the oxygen exhaust pipe three-way valve 23. The inlet of the oxygen exhaust pipe three-way valve 23 is connected to the outlet of the oxygen exhaust pipe of the oxygen-side gas-liquid separator 15 in the gas-liquid separator V. The two outlets of the oxygen exhaust pipe three-way valve 23 are connected to the spare oxygen storage tank 25 and the oxygen dryer 26 in the oxygen storage device VIII. The inlet is connected; on the hydrogen side, the hydrogen side pressure level sensor 18, the hydrogen discharge pipe pressure regulating valve 20, and the hydrogen discharge pipe pressure sensor 22 are installed on the gas sub-pipe connecting the hydrogen side pressure level sensor 18 and the hydrogen discharge pipe three-way valve 24 in the gas-liquid separation device V. The inlet of the hydrogen discharge pipe three-way valve 24 is connected to the outlet of the hydrogen discharge pipe of the hydrogen side gas-liquid separator 16 in the gas-liquid separation device V. The two outlets of the hydrogen discharge pipe three-way valve 24 are connected to the inlet of the spare hydrogen storage tank 29 and the deaerator 30 in the hydrogen storage device IX.

[0044] In the oxygen storage device VIII, the inlet of the spare oxygen storage tank 25 is connected to one outlet of the oxygen exhaust pipe three-way valve 23, the inlet of the oxygen dryer 26 is connected to the other outlet of the oxygen pipe three-way valve 23, the outlet of the oxygen dryer 26 is connected to the inlet of the oxygen buffer 27, and the outlet of the oxygen buffer 27 is connected to the inlet of the commonly used oxygen storage tank 28.

[0045] In the hydrogen storage device IX, the inlet of the spare hydrogen storage tank 29 is connected to one outlet of the hydrogen discharge pipe three-way valve 24, the inlet of the deoxygenator 30 is connected to the other outlet of the hydrogen discharge pipe three-way valve 24, the outlet of the deoxygenator 30 is connected to the inlet of the hydrogen dryer 31, the hydrogen dryer 31 is connected to the inlet of the hydrogen buffer 32, and the outlet of the hydrogen buffer 32 is connected to the inlet of the commonly used hydrogen storage tank 33.

[0046] In the water supply device II, water pump 4 is used to provide water for hydrogen production device IV. Water purification device 5 is used to purify the water supplied by water pump 4 to obtain purified water that meets the water standards of the electrolysis device. Purified water tank 6 is used to store purified water to prevent damage to PEM electrolyzer 14 in hydrogen production device IV due to sudden lack of water supply during operation, and to ensure that PEM electrolyzer 14 in hydrogen production device IV can be shut down smoothly in the event of no water supply. Purified water pump 7 can be set as a high-pressure purified water pump or a low-pressure purified water pump according to the actual needs of the system. It draws purified water from purified water tank 6 to supply water to hydrogen production device IV, and separates high-conductivity purified water and low-conductivity purified water through ion filter 8 to control the conductivity of purified water flowing into hydrogen production device IV to meet the operating requirements of PEM electrolyzer 14. Temperature controller 9 controls the temperature of purified water entering hydrogen production device IV from water supply device II so that it can meet the electrolysis water temperature of hydrogen production device IV.

[0047] The control center 10 in the front-end pipe pressure balancing device III is connected to the current sensor 11, and the oxygen-side pressure level sensor 17, hydrogen-side pressure level sensor 18, oxygen exhaust pipe pressure regulating valve 19, hydrogen exhaust pipe pressure regulating valve 20, oxygen exhaust pipe pressure sensor 21, hydrogen exhaust pipe pressure sensor 22, oxygen exhaust pipe three-way valve 23, and hydrogen exhaust pipe three-way valve 24 in the rear-end pipe pressure balancing device VI via electrical signals. The current sensor 11 is used to monitor the real-time current changes in each PEM electrolyzer 14. The oxygen-side pressure level sensor 17 and hydrogen-side pressure level sensor 18 are used to monitor the actual liquid level of the gas-liquid separation device V in real time. The oxygen exhaust pipe pressure sensor 21 and hydrogen exhaust pipe pressure sensor 22 are used to monitor the actual gas pipe pressure in the oxygen and hydrogen exhaust pipes of the PEM electrolyzer 14 in real time, as well as the actual oxygen and hydrogen production. At the actual speed, the control center 10 controls the switch 12 to adjust the input current value and the liquid level of the gas-liquid separation device, and controls the opening of the oxygen discharge pipe pressure regulating valve 19 and the hydrogen discharge pipe pressure regulating valve 20 to ensure the liquid level and pressure balance on both sides of the hydrogen production equipment, thereby ensuring the safety of the hydrogen production system. The control center 10 can realize the data adjustment of the above electro-hydrogen production system; the oxygen discharge pipe three-way valve 23 and the hydrogen discharge pipe three-way valve 24 are used to control the gas flow direction. When a PEM electrolyzer fails, the pressure of the oxygen discharge pipe and the hydrogen discharge pipe of the PEM electrolyzer changes drastically, affecting the pressure of the entire gas pipeline. By adjusting the oxygen discharge pipe three-way valve 23 and the hydrogen discharge pipe three-way valve 24 through the control center 10, the sub-gas pipeline is disconnected from the main gas pipeline, ensuring that the remaining PEM electrolyzers can continue to work safely.

[0048] The oxygen-side pressure level sensor 17 and the hydrogen-side pressure level sensor 18 acquire the actual liquid levels of the oxygen-side gas-liquid separator 15 and the hydrogen-side gas-liquid separator 16 in each PEM electrolyzer. They calculate the difference between the actual liquid levels on the oxygen and hydrogen sides and the preset liquid levels on the oxygen and hydrogen sides. Based on the difference between the actual and preset liquid levels, the control center 10 controls the pressure level sensor 14 to adjust the liquid levels of the oxygen-side gas-liquid separator 15 and the hydrogen-side gas-liquid separator 16. The control center also assists in adjusting the pressure regulating valves 19 and 20 of the oxygen and hydrogen discharge pipes to ensure the accuracy of the adjustment. This allows the liquid levels on both sides of the hydrogen production equipment to be balanced, ensuring the accuracy of the calculated difference between the actual liquid levels on the oxygen and hydrogen sides.

[0049] The oxygen-side gas-liquid separator 15 and the hydrogen-side gas-liquid separator 16 in the gas-liquid separation device V are used to effectively separate the liquid in the oxygen and hydrogen produced by the PEM electrolyzer 14 in the hydrogen production device IV, to prevent gas from entering the liquid pipeline or liquid from entering the gas pipeline, and to maintain the normal operation of the pipeline system.

[0050] The spare oxygen storage tank 25 in the oxygen storage device VIII is used to temporarily store oxygen when the electric hydrogen production system performs a self-test. The oxygen dryer 26 is used to absorb water vapor in the oxygen separated by the oxygen-side gas-liquid separator 15. The oxygen buffer 27 is used to absorb the impact force of oxygen.

[0051] The deoxygenator 30 in the hydrogen storage device IX is used to remove the small amount of oxygen that may be mixed in the hydrogen, thereby improving the purity of the hydrogen. The hydrogen dryer 31 is used to absorb the water vapor in the hydrogen separated by the hydrogen-side gas-liquid separator 16. The hydrogen buffer 32 is used to absorb the impact force of the hydrogen.

[0052] In this embodiment, the oxygen exhaust pipe pressure sensor 21 and hydrogen exhaust pipe pressure sensor 22 in the back-end pipe pressure balancing device VI acquire the actual gas pipe pressure of the oxygen exhaust pipe and the gas pipe pressure of the hydrogen exhaust pipe in the four PEM electrolyzers 14. The current sensor 11 monitors the real-time current of each PEM electrolyzer. When the gas pipe pressure does not meet the safe pressure relationship, the real-time current is compared with a preset current to ensure the accuracy of the comparison results. Within a reasonable hydrogen production efficiency range, the control center 10 adjusts the real-time current of the PEM electrolyzers 14 to control the hydrogen production rate and oxygen production rate, thereby adjusting the gas pipe pressure in the pipeline. The actual hydrogen production rate and oxygen production rate are calculated based on the real-time current. The pressure of the gas pipes in the oxygen and hydrogen discharge pipes is controlled according to the change in the gas production rate. The pressure is further assisted by the oxygen discharge pipe pressure regulating valve 19 and the hydrogen discharge pipe pressure regulating valve 20, so that the gas pipe pressures in the oxygen and hydrogen discharge pipes are within the safe threshold. This avoids the situation where the pressure difference in the gas pipes of the hydrogen discharge pipe of the hydrogen production equipment is too large, which may cause oxygen to flow back into the hydrogen production unit and mix with hydrogen, resulting in an explosion.

[0053] In this example, a control method for an electro-hydrogen production system is described, such as... Figure 3 As shown, it includes the following steps:

[0054] Step 1: Perform a self-test on the electro-hydrogen production system using the self-test control mode (first control mode), such as... Figure 4 As shown, start the pipe pressure balancing device and introduce a preset current into the PEM electrolyzer. Adjust the pipe pressure regulating valve to balance the gas pipe pressure of the oxygen discharge pipe and hydrogen discharge pipe of the PEM electrolyzer and meet the safe pipe pressure relationship.

[0055] First, connect all oxygen venting pipe three-way valves 23 and hydrogen venting pipe three-way valves 24 to the backup oxygen storage tank 25 and backup hydrogen storage tank 29. The oxygen-side pressure level sensor 17 and the hydrogen-side pressure level sensor 18 acquire the actual liquid levels of the oxygen-side gas-liquid separator 15 and the hydrogen-side gas-liquid separator 16, respectively. Determine if the actual liquid level is within the preset range. If not, adjust the liquid level via the oxygen-side pressure level sensor 17 and the hydrogen-side pressure level sensor 18 in the control center 10. Once the preset liquid level is met, activate the pipe pressure balancing device IV and supply the required pressure. A preset current is supplied to the PEM electrolyzer 14. After the PEM electrolyzer 14 is running smoothly, the pipe pressure balancing device IV monitors the actual gas pressure of the oxygen discharge pipe of each PEM electrolyzer 14 and adjusts the oxygen discharge pipe pressure regulating valve 19 and the hydrogen discharge pipe pressure regulating valve 20 so that the gas pressure of the oxygen discharge pipe and the actual gas pressure of the hydrogen discharge pipe of each PEM electrolyzer meet the safe pressure relationship. Then the self-test control of the electro-hydrogen production system is completed. The control center 10 controls the oxygen discharge pipe three-way valve 23 and the hydrogen discharge pipe three-way valve 24 to connect to the commonly used oxygen storage tank 28 and the commonly used hydrogen storage tank 33.

[0056] The required safe pressure relationship for the gas pressure in the oxygen venting pipe is shown in the following formula:

[0057]

[0058] in, The pressure is the actual gas pressure in the oxygen venting pipe of the k-th PEM electrolyzer, where k is the serial number of the PEM electrolyzer. In this embodiment, k is 1, 2, 3, or 4. The target gas pressure for the oxygen venting pipe of the PEM electrolyzer. As the first safety differential pressure, the target gas pressure of the oxygen exhaust pipe is set in this embodiment. The average value of the target gas pressure in the oxygen venting pipe of each PEM electrolyzer;

[0059] The oxygen venting pipe of the PEM electrolyzer has a target gas pressure. The calculation formula is shown below:

[0060]

[0061] The safe pressure relationship that the gas pressure in the hydrogen exhaust pipe must meet is shown in the following formula:

[0062]

[0063] in, The actual gas pressure in the hydrogen venting pipe of the k-th PEM electrolyzer is... The target gas pressure for the hydrogen venting pipe of the PEM electrolyzer. The second safety differential pressure is set in this embodiment as the average value of the target gas pressure in the hydrogen discharge pipe of each PEM electrolyzer.

[0064] The gas pressure of the target tube in the hydrogen discharge pipe of the PEM electrolyzer. The calculation formula is shown below:

[0065]

[0066] Assuming all oxygen venting pipes and all hydrogen venting pipes are of the same length, the pressure difference between the first and second safety pipes is calculated using the Hagen-Poseidon equation. The formula for calculating the pressure difference between the first and second safety pipes is as follows:

[0067]

[0068] in, The radius of the oxygen venting pipe, For oxygen viscosity, This refers to the length of the oxygen venting pipe. This represents the average flow rate of the oxygen exhaust pipe;

[0069] The formula for calculating the differential pressure in the second safety pipe is as follows:

[0070]

[0071] in, The radius of the hydrogen discharge pipe is... The viscosity of hydrogen gas, The length of the hydrogen discharge pipe, This represents the average flow rate of the hydrogen discharge pipe;

[0072] Step 2: Start hydrogen production. During the hydrogen production process, determine whether the gas pressure of the oxygen and hydrogen venting pipes of the PEM electrolyzer meets the safe pressure relationship. Use current control (second control method) and liquid level control (third control method) to adjust the pipe pressure. After the pipe pressure meets the safe pressure relationship, store the oxygen and hydrogen in a conventional oxygen and hydrogen storage device.

[0073] In current control (second control mode), such as Figure 5As shown, the oxygen exhaust pipe pressure sensor 21 and the hydrogen exhaust pipe pressure sensor 22 monitor the actual gas pressure in the oxygen and hydrogen exhaust pipes of each PEM electrolyzer 14 and transmit the data back to the control center 10. When the actual gas pressure meets the safe pressure relationship, the control center 10 controls the oxygen exhaust pipe three-way valve 23 and the hydrogen exhaust pipe three-way valve 24 to connect to the commonly used oxygen storage tank 28 and the commonly used hydrogen storage tank 33. When the actual gas pressure does not meet the safe pressure relationship, the actual oxygen production rate and hydrogen production rate of the corresponding PEM electrolyzer 14 are calculated through real-time current, and the real-time current and the pressure of the oxygen and hydrogen exhaust pipes are obtained. The relationship between the actual gas pressure in the hydrogen pipeline is controlled by the control center 12 through PID control. Within a reasonable hydrogen production efficiency range, the real-time current input to each PEM electrolyzer 14 is changed. Based on the real-time current, the gas pressure in the oxygen and hydrogen discharge pipelines is controlled. At the same time, the pressure regulating valves 19 and 20 of the oxygen and hydrogen discharge pipelines are adjusted for auxiliary regulation, so that the gas pressure in the oxygen and hydrogen discharge pipelines meets the safe pressure relationship. This avoids the possibility that the pressure difference on the oxygen side of the hydrogen production equipment is too large, which could cause oxygen to flow back into the hydrogen production unit and mix with hydrogen, resulting in an explosion.

[0074] Based on the Ferrari principle, the actual oxygen and hydrogen production rates of the PEM electrolyzer under operating conditions are calculated using the following formulas:

[0075]

[0076]

[0077] in, The actual oxygen production rate (mol / s) of the k-th PEM electrolyzer under operating conditions. The actual hydrogen production rate (mol / s) of the k-th PEM electrolyzer under operating conditions is given, where n is the number of PEM electrolyzers connected in series. In this embodiment, n is 4. Let F be the real-time current of the k-th PEM electrolyzer, and F be the Ferrari constant. For Ferrari efficiency;

[0078] The formula for calculating the actual oxygen flow rate of each PEM electrolyzer under operating conditions is as follows:

[0079]

[0080] in, Let L be the actual oxygen flow rate (L / s) produced by the k-th PEM electrolyzer under operating conditions. The cross-sectional area of ​​the oxygen venting pipe is the same as that of the PEM electrolytic cell;

[0081] Based on the ideal gas law, the actual gas flow rate under operating conditions is converted to the gas flow rate under standard conditions using the following formula:

[0082]

[0083] in, For operating pressure, Standard atmospheric pressure The operating temperature of the electrolytic cell The absolute temperature is obtained under standard conditions. The actual gas flow rate under operating conditions. This refers to the gas flow rate under standard conditions.

[0084] The actual oxygen flow rate of each PEM electrolyzer under operating conditions is converted to the oxygen flow rate of each PEM electrolyzer under standard conditions using the ideal gas law. The calculation formula is as follows:

[0085]

[0086] in, The oxygen flow rate (L / s) generated by the kth PEM electrolyzer under standard conditions;

[0087] The formula for calculating the actual hydrogen flow rate of each PEM electrolyzer under operating conditions is as follows:

[0088]

[0089] in, Let L be the actual hydrogen flow rate (L / s) produced by the k-th PEM electrolyzer under operating conditions. This refers to the cross-sectional area of ​​the hydrogen discharge pipe;

[0090] The actual hydrogen flow rate of each PEM electrolyzer under operating conditions is converted to the hydrogen flow rate (L / s) of each PEM electrolyzer under standard conditions using the ideal gas law. The calculation formula is as follows:

[0091]

[0092] in, Let L be the hydrogen flow rate (L / s) generated by the k-th PEM electrolyzer under standard conditions.

[0093] Calculate the mathematical relationship between the real-time current and the actual gas pipeline pressure on the oxygen and hydrogen sides under operating conditions.

[0094] On the oxygen side, under operating conditions, the actual gas pressure in the oxygen venting pipe of each PEM electrolyzer satisfies the following formula:

[0095]

[0096] in, It is the gas constant;

[0097] The mathematical relationship between the real-time current of the PEM electrolyzer and the actual gas pressure in the PEM electrolyzer's oxygen venting pipe under the corresponding operating conditions is shown in the following formula:

[0098]

[0099] On the hydrogen side, under operating conditions, the actual gas pressure in the hydrogen venting pipe of each PEM electrolyzer satisfies the following formula:

[0100]

[0101] The mathematical relationship between the real-time current of the PEM electrolyzer and the actual gas pressure in the hydrogen discharge pipe of the PEM electrolyzer under operating conditions is shown in the following formula:

[0102]

[0103] Control center 10 calculates the corresponding control signal through PID control. This control signal is used to adjust the input current of the electrolyzer and continuously correct the pressure in the oxygen pipeline, stabilizing it near the target value, thereby achieving automatic adjustment and stable operation of the system. The PID controller uses three parts—proportional (P), integral (I), and derivative (D)—to regulate the deviation. Proportional control provides an immediate response based on the current deviation, integral control eliminates long-term deviations, and derivative control anticipates the trend of deviation changes. The PID control formula, derived from the PID control principle, is shown below:

[0104]

[0105]

[0106] in, The control signal is input to the control center; t represents time. This is the proportional gain parameter; This is the integral gain parameter; This is the differential gain parameter; This is the current error; The target value; This is the actual value;

[0107] By transforming the PID control formula and substituting the inputs, we obtain the PID control formulas for the oxygen side and the hydrogen side.

[0108] The PID control formula for the oxygen side is shown below:

[0109]

[0110]

[0111] in, This is the oxygen-side control signal. This refers to the oxygen-side proportional gain parameter; This refers to the oxygen-side integral gain parameter; This refers to the differential gain parameter on the oxygen side. This is due to an error in the oxygen pipeline. This represents the instantaneous pressure of the target gas pipe in the oxygen venting pipe under standard conditions. This represents the instantaneous pressure of the actual gas in the oxygen venting pipe under standard conditions.

[0112] The PID control formula for the hydrogen side is shown below:

[0113]

[0114]

[0115] in, This is the oxygen-side control signal. For the hydrogen-side proportional gain parameter; The integral gain parameter on the hydrogen side; The differential gain parameter on the hydrogen side; Error in the hydrogen pipeline; This represents the instantaneous pressure of the target gas tube in the hydrogen discharge pipe under standard conditions. This represents the instantaneous pressure of the actual gas in the hydrogen discharge pipe under standard conditions.

[0116] In liquid level control (third control method), such as Figure 6 As shown, the oxygen exhaust pipe pressure sensor 21 and the hydrogen exhaust pipe pressure sensor 22 acquire the actual gas pipe pressures of the oxygen and hydrogen exhaust pipes of the PEM electrolyzer 14. The oxygen-side pressure-type liquid level sensor 17 and the hydrogen-side pressure-type liquid level sensor 18 acquire the actual liquid levels of the oxygen-side gas-liquid separator 15 and the hydrogen-side gas-liquid separator 16 of the PEM electrolyzer 14. When the actual pipe pressure does not meet the safe pressure relationship, the actual liquid level value on the hydrogen side or oxygen side is compared with the preset liquid level. When the difference between the actual liquid level and the preset liquid level is too large, the pressure-type liquid level sensor is controlled by the control center 10 based on the difference between the actual liquid level difference and the preset liquid level difference. Sensor 14 adjusts the liquid levels of the oxygen-side gas-liquid separator 15 and the hydrogen-side gas-liquid separator 16, and further regulates the pressure of the oxygen and hydrogen discharge pipes by adjusting the pressure regulating valves 19 and 20, thereby balancing the pipe pressures to ensure that the gas pressures of both the oxygen and hydrogen discharge pipes meet safe pressure requirements. Liquid level control ensures the accuracy of the adjustments made to the oxygen and hydrogen discharge pipe pressure regulating valves 19 and 20, thus balancing the liquid levels of each pipe on the oxygen and hydrogen sides of the hydrogen production unit IV, ensuring that the gas pressures of both oxygen and hydrogen meet safe pressure requirements. This prevents excessive pressure differences on the oxygen side of the hydrogen production unit, which could lead to oxygen flowing back into the unit and mixing with hydrogen, potentially causing an explosion.

[0117] In this embodiment, the second control method and the third control method can be used in combination;

[0118] Step 3: Set the emergency control mode (fourth control mode). When the pipe pressure balancing device detects that the gas pipe pressure of the oxygen or hydrogen venting pipe of the PEM electrolyzer exceeds the preset standard deviation of the pipe pressure, the control center controls the three-way valve to close with the main pipeline and connect with the backup oxygen and hydrogen storage tanks. The input circuit of the PEM electrolyzer is disconnected. After the maintenance is completed, the self-test control will be performed again.

[0119] In emergency control mode, when the oxygen venting pipe pressure sensor 21 and the hydrogen venting pipe pressure sensor 22 detect that the gas pressure of the oxygen venting pipe or hydrogen venting pipe of a certain PEM electrolyzer exceeds the preset standard deviation of the pipe pressure, that is, when the gas pressure difference of the oxygen venting pipe or hydrogen venting pipe of the PEM electrolyzer is much greater than the adjustable pipe pressure difference within the safe range, and cannot be adjusted by the second and third control methods, the control center 10 will control the oxygen venting pipe three-way valve 23 and the hydrogen venting pipe three-way valve 24 of the faulty PEM electrolyzer to close them to the main pipeline and connect them to the backup oxygen storage tank 25 and the backup hydrogen storage tank 29. At this time, the control center 10 controls the current switch 12 of the faulty PEM electrolyzer to open, and the PEM electrolyzer enters maintenance. After the self-test control meets the requirements, the oxygen venting pipe three-way valve 23 and the hydrogen venting pipe three-way valve 24 are reconnected to the main output gas pipeline.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. An electro-hydrogen production system, characterized in that: It includes power supply equipment, water supply equipment, front-end pipeline pressure balancing equipment, hydrogen production equipment, gas-liquid separation equipment, back-end pipeline pressure balancing equipment, heat conversion equipment, oxygen storage equipment, and hydrogen storage equipment. One end of the power supply device is connected to the power grid, and the other end is connected to the hydrogen production device through a front-end pipe pressure balancing device, which is used to supply power to the electro-hydrogen production system; the hydrogen production device is connected to a gas-liquid separation device, which is used to electrolyze water to produce oxygen and hydrogen. The gas-liquid separation unit is connected to the oxygen storage unit and the hydrogen storage unit via a rear-end pipe pressure balancing device to separate liquids from oxygen and hydrogen. The oxygen storage unit stores oxygen produced by the hydrogen production unit, and the hydrogen storage unit stores hydrogen produced by the hydrogen production unit. The front-end pipe pressure balancing device is connected to the power supply unit and the hydrogen production unit, and the rear-end pipe pressure balancing device is connected to the gas-liquid separation unit, the oxygen storage unit, and the hydrogen storage unit. The front-end and rear-end pipe pressure balancing devices are used to monitor the real-time current changes, actual gas pipe pressure, and actual liquid level of the electro-hydrogen production system, and to control the hydrogen production unit, balancing the gas pipe pressures of each oxygen and hydrogen exhaust pipe. The water supply unit is connected to the hydrogen production unit to supply water to the hydrogen production unit. The heat conversion unit is connected to the hydrogen production unit to cool the hydrogen production unit and recover waste heat to heat the water in the hydrogen production unit. The hydrogen production device includes a water pipeline switch and a PEM electrolyzer; the water pipeline switch is connected to the PEM electrolyzer, and each PEM electrolyzer is connected to a gas-liquid separation device. The gas-liquid separation device includes an oxygen-side gas-liquid separator and a hydrogen-side gas-liquid separator; the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator are respectively connected to the oxygen storage device and the hydrogen storage device through a rear-end pipe pressure balancing device; the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator are used to effectively separate the liquid in the oxygen and hydrogen produced by the PEM electrolyzer in the hydrogen production device. The front-end pipe pressure balancing device includes a control center, a current sensor, and a current switch; the control center is connected to the current sensor, the current sensor is connected to the current switch, and the current switch is connected to the hydrogen production unit; the control center and the current sensor are connected via an electrical signal, the current sensor is used to monitor the real-time current change of each PEM electrolyzer, and the control center controls the switching of the current switch, adjusts the input current value, and the liquid level of the gas-liquid separation unit. The back-end pipe pressure balancing device includes an oxygen-side pressure level sensor, a hydrogen-side pressure level sensor, an oxygen exhaust pipe pressure regulating valve, a hydrogen exhaust pipe pressure regulating valve, an oxygen exhaust pipe pressure sensor, a hydrogen exhaust pipe pressure sensor, an oxygen exhaust pipe three-way valve, and a hydrogen exhaust pipe three-way valve. The back-end pipe pressure balancing device is divided into an oxygen side and a hydrogen side. On the oxygen side, the oxygen-side pressure level sensor, the oxygen exhaust pipe pressure regulating valve, and the oxygen exhaust pipe pressure sensor are installed on the gas sub-pipe connecting the oxygen-side gas-liquid separator and the oxygen exhaust pipe three-way valve. The inlet of the oxygen exhaust pipe three-way valve is connected to the oxygen-side gas in the gas-liquid separator. The oxygen discharge pipe outlet of the liquid separator is connected, and the two outlet valves of the oxygen discharge pipe three-way valve are connected to the spare oxygen storage tank and the oxygen dryer inlet in the oxygen storage device; on the hydrogen side, the hydrogen side pressure-type liquid level sensor, the hydrogen discharge pipe pressure regulating valve, and the hydrogen discharge pipe pressure sensor are installed on the gas sub-pipe connecting the hydrogen side gas-liquid separator and the hydrogen discharge pipe three-way valve in the gas-liquid separation device. The inlet valve of the hydrogen discharge pipe three-way valve is connected to the hydrogen discharge pipe outlet of the hydrogen side gas-liquid separator in the gas-liquid separation device, and the two outlet valves of the hydrogen discharge pipe three-way valve are connected to the spare hydrogen storage tank and the deaerator inlet in the hydrogen storage device; The oxygen-side pressure level sensor, hydrogen-side pressure level sensor, oxygen exhaust pipe pressure regulating valve, hydrogen exhaust pipe pressure regulating valve, oxygen exhaust pipe pressure sensor, hydrogen exhaust pipe pressure sensor, oxygen exhaust pipe three-way valve, and hydrogen exhaust pipe three-way valve are connected to the control center of the front-end pipe pressure balancing device via electrical signals. The oxygen-side pressure level sensor and hydrogen-side pressure level sensor are used to monitor the actual liquid level of the gas-liquid separation device in real time. The oxygen exhaust pipe pressure sensor and hydrogen exhaust pipe pressure sensor are used to monitor the actual gas pipe pressure of the oxygen exhaust pipe and hydrogen exhaust pipe of the PEM electrolyzer in real time. The oxygen exhaust pipe pressure regulating valve... The opening of the valves and the hydrogen discharge pipe pressure regulating valves is controlled by the control center to ensure the liquid level and pressure balance on both sides of the hydrogen production equipment, thereby ensuring the safety of the hydrogen production system. The oxygen discharge pipe three-way valve and the hydrogen discharge pipe three-way valve are used to control the gas flow direction. When a PEM electrolyzer malfunctions, the pressure of the gas pipes of that PEM electrolyzer will change drastically, affecting the pressure of the entire gas pipeline. By adjusting the oxygen discharge pipe three-way valve and the hydrogen discharge pipe three-way valve through the control center, the sub-gas pipeline is disconnected from the main gas pipeline, ensuring that the remaining PEM electrolyzers can continue to operate safely.

2. The electro-hydrogen production system according to claim 1, characterized in that: The power supply device includes a step-down transformer, an inverter, and an electric switch; one end of the step-down transformer is connected to the power grid, and the other end is connected to the inverter; the inverter is connected to the electric switch, and the electric switch is connected to the front-end voltage balancing device. The water supply device includes a water pump, a water purification device, a purified water tank, a purified water pump, an ion filter, and a temperature controller. The outlet of the water pump is connected to the inlet of the water purification device, the outlet of the water purification device is connected to the inlet of the purified water tank, the outlet of the purified water tank is connected to the inlet of the purified water pump, the outlet of the purified water pump is connected to the inlet of the ion filter, and the outlet of the ion filter is connected to the hydrogen production device via the temperature controller. The water pump provides water to the hydrogen production device, the water purification device purifies the water supplied by the water pump to obtain purified water, and the purified water tank stores the purified water. The purified water pump draws purified water from the purified water tank and supplies it to the hydrogen production device. The conductivity of the purified water flowing into the hydrogen production device is controlled by the ion filter to meet operational requirements, and the temperature controller controls the temperature of the purified water entering the hydrogen production device from the water supply device.

3. The electro-hydrogen production system according to claim 2, characterized in that: The oxygen storage device includes a backup oxygen storage tank, an oxygen dryer, an oxygen buffer, and a regular oxygen storage tank. The inlet of the backup oxygen storage tank is connected to one outlet valve of the three-way valve of the oxygen exhaust pipe, the inlet of the oxygen dryer is connected to the other outlet valve of the three-way valve of the oxygen exhaust pipe, the outlet of the oxygen dryer is connected to the inlet of the oxygen buffer, and the outlet of the oxygen buffer is connected to the inlet of the regular oxygen storage tank. The backup oxygen storage tank is used to temporarily store oxygen during the self-test of the electric hydrogen production system, the oxygen dryer is used to absorb water vapor in the oxygen separated by the oxygen-side gas-liquid separator, and the oxygen buffer is used to absorb the impact force of the oxygen. The hydrogen storage device includes a backup hydrogen storage tank, a deoxygenator, a hydrogen dryer, a hydrogen buffer, and a main hydrogen storage tank. The inlet of the backup hydrogen storage tank is connected to one outlet valve of the three-way valve on the hydrogen discharge pipe, the inlet of the deoxygenator is connected to the other outlet valve of the three-way valve on the hydrogen discharge pipe, the outlet of the deoxygenator is connected to the inlet of the hydrogen dryer, the hydrogen dryer is connected to the inlet of the hydrogen buffer, and the outlet of the hydrogen buffer is connected to the inlet of the main hydrogen storage tank. The deoxygenator is used to remove oxygen that may be mixed in the hydrogen, thereby improving the purity of the hydrogen. The hydrogen dryer is used to absorb water vapor in the hydrogen separated by the hydrogen-side gas-liquid separator, and the hydrogen buffer is used to absorb the impact force of the hydrogen.

4. A control method for an electro-hydrogen production system, implemented based on the electro-hydrogen production system described in claim 3, characterized in that: Includes the following steps: Step 1: Perform a self-test of the electro-hydrogen production system using the self-test control method, start the pipe pressure balancing device and introduce a preset current into the PEM electrolyzer, and adjust the pipe pressure regulating valve to balance the gas pipe pressure of the oxygen discharge pipe and hydrogen discharge pipe of the PEM electrolyzer and meet the safe pipe pressure relationship. Step 2: Start hydrogen production. During the hydrogen production process, determine whether the gas pressure of the oxygen and hydrogen venting pipes of the PEM electrolyzer meets the safe pressure relationship. Adjust the pipe pressure using current control and liquid level control. After the pipe pressure meets the safe pressure relationship, store the oxygen and hydrogen in a conventional oxygen and hydrogen storage device. Step 3: Set the emergency control mode. When the pipe pressure balancing device detects that the gas pipe pressure of the oxygen or hydrogen venting pipe of the PEM electrolyzer exceeds the preset standard deviation of the pipe pressure, the control center controls the three-way valve to close with the main pipeline and connect with the backup oxygen and hydrogen storage tanks. The input circuit of the PEM electrolyzer is disconnected. After the maintenance is completed, the self-test control will be performed again.

5. The control method for an electro-hydrogen production system according to claim 4, characterized in that: The specific method of step 1 is as follows: First, connect all oxygen venting pipe three-way valves and hydrogen venting pipe three-way valves to the backup oxygen storage tank and backup hydrogen storage tank. The oxygen-side pressure level sensor and hydrogen-side pressure level sensor acquire the actual liquid levels of the oxygen-side gas-liquid separator and hydrogen-side gas-liquid separator, respectively. Determine if the actual liquid level is within the preset level. If not, adjust the liquid level using the oxygen-side pressure level sensor and hydrogen-side pressure level sensor in the control center. Once the preset level is met, start the pipe pressure balancing device. The system is set up and a preset current is supplied to all PEM electrolyzers. Once the PEM electrolyzers are running smoothly, the pipe pressure balancing device monitors the actual gas pressure of the oxygen vent pipe of each PEM electrolyzer and adjusts the oxygen vent pipe pressure regulating valve and the hydrogen vent pipe pressure regulating valve to ensure that the actual gas pressure of the oxygen vent pipe and the actual gas pressure of the hydrogen vent pipe of each PEM electrolyzer meet the safe pressure relationship. Then, the self-test control of the electro-hydrogen production system is completed, and the control center controls the oxygen vent pipe three-way valve and the hydrogen vent pipe three-way valve to connect to the commonly used oxygen storage tank and the commonly used hydrogen storage tank.

6. The control method for an electro-hydrogen production system according to claim 5, characterized in that: The specific method for current control in step 2 is as follows: In current control, the oxygen venting pipe pressure sensor and the hydrogen venting pipe pressure sensor monitor the actual gas pipe pressure of the oxygen venting pipe and hydrogen venting pipe of each PEM electrolyzer and transmit the data back to the control center. When the actual gas pipe pressure meets the safe pressure relationship, the control center controls the oxygen venting pipe three-way valve and the hydrogen venting pipe three-way valve to connect to the commonly used oxygen storage tank and the commonly used hydrogen storage tank. When the actual gas pipe pressure does not meet the safe pressure relationship, the actual oxygen production rate and hydrogen production rate of the corresponding PEM electrolyzer are calculated through real-time current to obtain the relationship between the real-time current and the actual gas pipe pressure of the oxygen venting pipe and the hydrogen venting pipe. The control center changes the real-time current input to each PEM electrolyzer through PID control within a reasonable hydrogen production efficiency range, controls the gas pipe pressure of the oxygen venting pipe and the hydrogen venting pipe according to the real-time current, and simultaneously adjusts the oxygen venting pipe pressure regulating valve and the hydrogen venting pipe pressure regulating valve for auxiliary adjustment so that the gas pipe pressure of the oxygen venting pipe and the hydrogen venting pipe meets the safe pressure relationship.

7. The control method for an electro-hydrogen production system according to claim 6, characterized in that: The specific method for liquid level control in step 2 is as follows: In liquid level control, the pressure sensors of the oxygen discharge pipe and the hydrogen discharge pipe acquire the actual gas pipe pressure of the oxygen discharge pipe and the hydrogen discharge pipe of the PEM electrolyzer, and the pressure-type liquid level sensors of the oxygen side and the hydrogen side acquire the actual liquid level of the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator of the PEM electrolyzer. When the actual pipe pressure does not meet the safe pressure relationship, the actual liquid level value of the hydrogen side or the oxygen side is compared with the preset liquid level. When the difference between the actual liquid level and the preset liquid level is too large, the liquid level of the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator is adjusted by using the pressure-type liquid level sensor controlled by the control center according to the difference between the actual liquid level difference and the preset liquid level difference. The pressure balance of the pipeline is adjusted by using the pressure regulating valves of the oxygen discharge pipe and the hydrogen discharge pipe to ensure that the gas pipe pressure of the oxygen discharge pipe and the hydrogen discharge pipe meets the safe pressure relationship.

8. The control method for an electro-hydrogen production system according to claim 7, characterized in that: The specific method of step 3 is as follows: In the emergency control mode, when the oxygen discharge pipe pressure sensor and the hydrogen discharge pipe pressure sensor detect that the gas pipe pressure of a certain PEM electrolyzer's oxygen discharge pipe or hydrogen discharge pipe exceeds the preset standard deviation of pipe pressure, that is, when the gas pipe pressure difference of the PEM electrolyzer's oxygen discharge pipe or hydrogen discharge pipe is much greater than the adjustable pipe pressure difference within the safe range, it cannot be adjusted by the second control and third control methods. The control center will control the oxygen discharge pipe three-way valve and the hydrogen discharge pipe three-way valve of the faulty PEM electrolyzer to close them to the main pipeline and connect them to the backup oxygen storage tank and the backup hydrogen storage tank. At this time, the control center controls the current switch of the faulty PEM electrolyzer to disconnect, and the PEM electrolyzer enters maintenance. After the self-test control meets the requirements, the oxygen discharge pipe three-way valve and the hydrogen discharge pipe three-way valve are reconnected to the main output gas pipeline.

Images