High-capacity electric hydrogen production system and control method thereof

Abstract

The invention provides a high-capacity electric hydrogen production system and a control method thereof, and relates to the technical field of water electrolysis hydrogen production safe operation. On one hand, a high-capacity electric hydrogen production system is provided, a pipe pressure balancing device is additionally arranged, and the current variable quantity of a PEM electrolytic bath, the actual gas pipe pressure intensity of an oxygen discharging pipe and a hydrogen discharging pipe and the actual liquid level of a gas-liquid separation device are monitored in real time; the real-time current of the PEM electrolytic cell is adjusted through the control center to adjust the pressure of the gas pipe of the pipeline, and the pressure of the gas pipe of the oxygen discharging pipe and the pressure of the gas pipe of the hydrogen discharging pipe meet the safe pressure relation through auxiliary adjustment of the pipe pressure adjusting valve; on the other hand, the invention provides a control method of the high-capacity electric hydrogen production system, and safe operation of the electric hydrogen production system is realized through self-checking control, current control, liquid level control and emergency control. According to the invention, the safety of the system is improved, and the purity and efficiency of the gas are ensured, so that the high-capacity PEM electrolytic bath is more reliable and efficient in practical application.

Description

Technical Field

[0001] The present invention relates to the technical field of safe operation of hydrogen production by electrolysis of water, and in particular to a large-capacity electric hydrogen production system and a control method thereof. Background Art

[0002] As the demand for low-carbon emission reduction grows, green hydrogen production technology has attracted much attention. Hydrogen production by water electrolysis is one of the methods with the lowest carbon emissions. Hydrogen has great potential in many fields and can effectively reduce greenhouse gas emissions. Proton exchange membrane water electrolysis hydrogen production technology represents the direction of green hydrogen production and promotes the integration and development with renewable energy. During the electrolysis process, water is decomposed into oxygen, hydrogen ions and electrons at the anode. Hydrogen ions enter the cathode through the proton exchange membrane. Electrons flow out of the anode and pass through the power circuit to the cathode, while the power supply provides driving force. On the cathode side, the two protons and electrons recombine to produce hydrogen.

[0003] At present, the mainstream research direction for the improvement of electric hydrogen production equipment is to balance the pressure on the oxygen side and the hydrogen side, so as to ensure the balance of the pipeline pressure on the oxygen side and the hydrogen side, avoid the large difference in the pipeline pressure on the oxygen side and the hydrogen side, cause the mixing of oxygen and hydrogen, and cause dangerous accidents such as explosion of the device. A pressure balance method for the oxygen side and the hydrogen side is proposed in the Chinese patent "CN116356346A Hydrogen Production System and Hydrogen Production System Control Method". The method controls the hydrogen production equipment by setting the first actual pressure, the first actual liquid level, the second actual liquid level and the actual current change amount passed into the PEM electrolyzer to ensure the safety of the hydrogen production equipment. The patent adopts some control methods such as PID control, negative feedback control, sliding film control, etc. to control the pressure, liquid level and current, so as to ensure that the hydrogen production system maintains the pressure balance and liquid level balance on the oxygen production side and the hydrogen production side at all times. Avoid the possibility that the hydrogen production volume may change drastically at any time, causing the safety risk of the hydrogen production system to exceed the safety threshold and cause the safety risk of the hydrogen production system.

[0004] At present, the gas pressure balance of the water electrolysis hydrogen production device is mainly to balance the pipeline pressure on the oxygen side and the hydrogen side of a single PEM electrolyzer. Due to the insufficient capacity of a single PEM electrolyzer, multiple PEM electrolyzers are usually connected in series to form a large-capacity PEM electrolyzer. At this time, in order to save pipeline materials, the gas pipelines on the hydrogen side of all PEM electrolyzers will be connected in parallel, and then connected to the total hydrogen pipeline and input into the hydrogen tank. Similarly, the gas pipelines on the oxygen side are connected in parallel, connected to the total oxygen pipeline, and then input into the oxygen tank. When multiple PEM electrolyzers are running at the same time, when ensuring the gas pressure balance on the hydrogen side and the oxygen side of a single PEM electrolyzer, it is not considered that the pressure of the oxygen side of each PEM or the hydrogen gas pipeline in parallel should be kept consistent. A disturbance in a PEM electrolyzer causes the pipeline pressure on the hydrogen or oxygen side of the electrolyzer to be too high or too low, resulting in a large difference in pipeline pressure on the same gas side of different PEM electrolyzers, which may cause gas reflux and cause the mixture of oxygen and hydrogen to explode. How to achieve the balance of pressure and liquid level on both sides of the electrolytic water hydrogen production system at all times has become an urgent problem to be solved. Summary of the invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art. In order to ensure that a multi-electrolyzer electrolysis device can operate normally under safe conditions, a hydrogen production system and a control method for the hydrogen production system are provided to achieve the goal of maintaining the pressure balance of gases in different pipelines at all times when the multi-electrolyzer water electrolysis hydrogen production system is operating.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] On the one hand, the present invention provides a large-capacity electric 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 the front-end pipe pressure balancing device, so as to supply power to the electric hydrogen production system; the hydrogen production device is connected to the gas-liquid separation device, so as to electrolyze water to produce oxygen and hydrogen; the gas-liquid separation device is connected to the oxygen storage device and the hydrogen storage device through the rear-end pipe pressure balancing device, so as to separate the liquid in 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, and the front-end pipe pressure balancing device and the rear-end pipe pressure balancing device are used to monitor the real-time current change, the actual gas pipe pressure and the actual liquid level of the electric hydrogen production system in real time, and control the hydrogen production device to balance the gas pipe pressures of each oxygen exhaust pipe and hydrogen exhaust pipe; the water supply device is connected to the hydrogen production device, so as to supply water to the hydrogen production device; the heat conversion device is connected to the hydrogen production device, so as to cool the hydrogen production device and recover the waste heat to heat the water supplied to the hydrogen production device.

[0009] Preferably, 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 tube voltage balancing device.

[0010] Preferably, the water supply device comprises a water pump, a water purification device, a purified water tank, a purified water pump, an ion filter and a temperature controller; the water outlet of the water pump is connected to the water inlet of the water purification device, the water outlet of the water purification device is connected to the water inlet of the purified water tank, the water outlet of the purified water tank is connected to the water inlet of the purified water pump, the water outlet of the purified water pump is connected to the water inlet of the ion filter, and the water outlet of the ion filter is connected to the hydrogen production device through the temperature controller; the water pump is used to provide a water source for the hydrogen production device, the water purification device is used to purify the water provided by the water pump to obtain purified water, and the purified water tank is used to store purified water; the purified water pump draws purified water from the purified water tank to supply water to the hydrogen production device, and controls the conductivity of the purified water flowing into the hydrogen production device through the ion filter to meet the operating requirements, and 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 comprises 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 comprises 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 generated 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 is connected to the current sensor through an electrical signal, the current sensor is used to monitor the real-time current change of each PEM electrolyzer in real time, and the control center controls the switch of the current switch, adjusts the input current value and the liquid level of the gas-liquid separation device.

[0014] Preferably, the rear-end pipe pressure balancing device comprises an oxygen side pressure-type liquid level sensor, a hydrogen side pressure-type liquid 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 rear-end pipe pressure balancing device is divided into an oxygen side and a hydrogen side. On the oxygen side, the oxygen side pressure-type liquid level sensor, the oxygen exhaust pipe pressure regulating valve and the oxygen exhaust pipe pressure sensor are installed on the gas sub-pipeline connected between the oxygen side gas-liquid separator and the oxygen exhaust pipe three-way valve. The air inlet valve port of the oxygen exhaust pipe three-way valve is connected to the oxygen in the gas-liquid separation device. The exhaust pipe outlet of the side gas-liquid separator is connected, and the two exhaust valve ports of the three-way valve of the oxygen exhaust pipe are connected to the spare oxygen storage tank and the air inlet of the oxygen dryer in the oxygen storage device; on the hydrogen side, the hydrogen side pressure level sensor, the hydrogen exhaust pipe pressure regulating valve, and the hydrogen exhaust pipe pressure sensor are installed on the gas sub-pipeline connected between the hydrogen side gas-liquid separator and the hydrogen exhaust pipe three-way valve in the gas-liquid separation device, the air inlet valve port of the hydrogen exhaust pipe three-way valve is connected to the exhaust pipe outlet of the hydrogen side gas-liquid separator in the gas-liquid separation device, and the two exhaust valve ports of the three-way valve of the hydrogen exhaust pipe are connected to the spare hydrogen storage tank and the air inlet of 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 through 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 opening of the three-way valve and the hydrogen discharge pipe pressure regulating valve is controlled by the control center to ensure the liquid level balance 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 flow direction of the gas. When a PEM electrolyzer fails, the gas pipe pressure of the oxygen discharge pipe and the hydrogen discharge pipe of the PEM electrolyzer changes drastically and affects the pressure of the entire gas pipeline. The control center adjusts the oxygen discharge pipe three-way valve and the hydrogen discharge pipe three-way valve to disconnect the sub-gas pipeline from the main gas pipeline, ensuring that the remaining PEM electrolyzers can continue to work safely.

[0016] Preferably, the oxygen storage device includes a spare oxygen storage tank, an oxygen dryer, an oxygen buffer and a commonly used oxygen storage tank; the air inlet of the spare oxygen storage tank is connected to an air outlet valve port of the three-way valve of the oxygen exhaust pipe, the air inlet of the oxygen dryer is connected to the other air outlet valve port of the three-way valve of the oxygen exhaust pipe, the air outlet of the oxygen dryer is connected to the air inlet of the oxygen buffer, and the air outlet of the oxygen buffer is connected to the air inlet of the commonly used oxygen storage tank; the spare oxygen storage tank is used to temporarily store oxygen when the electric hydrogen production system performs self-inspection, 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 comprises a spare hydrogen storage tank, a deaerator, a hydrogen dryer, a hydrogen buffer and a common hydrogen storage tank; the air inlet of the spare hydrogen storage tank is connected to one of the air outlet valves of the three-way valve of the hydrogen discharge pipe, the air inlet of the deaerator is connected to the other air outlet valve of the three-way valve of the hydrogen discharge pipe, the air outlet of the deaerator is connected to the air inlet of the hydrogen dryer, the hydrogen dryer is connected to the air inlet of the hydrogen buffer, and the air outlet of the hydrogen buffer is connected to the air inlet of the common hydrogen storage tank; the deaerator is used to remove oxygen that may be mixed in the hydrogen to improve 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 a large-capacity electric hydrogen production system comprises the following steps:

[0019] Step 1: Use the self-check control method to perform a self-check on the large-capacity electric hydrogen production system, start the pipe pressure balancing device and pass a preset current into the PEM electrolyzer, and adjust the pipeline pressure regulating valve to balance the gas pipe pressure of the PEM electrolyzer oxygen exhaust pipe and hydrogen exhaust pipe and meet the safety pipe pressure relationship;

[0020] First, all oxygen exhaust pipe three-way valves and hydrogen exhaust pipe three-way valves are connected to the spare oxygen storage tank and the spare hydrogen storage tank. The oxygen side pressure level sensor and the hydrogen side pressure level sensor obtain the actual liquid level of the oxygen side gas-liquid separator and the hydrogen side gas-liquid separator, and judge whether the actual liquid level is at the preset liquid level. If not, the liquid level is adjusted by the oxygen side pressure level sensor and the hydrogen side pressure level sensor of the control center. After the preset liquid level is met, the pipe pressure balancing device is started, and the preset current is passed to all PEM electrolyzers. When the PEM electrolyzer runs smoothly, the pipe pressure balancing device monitors the actual gas pipe pressure of the oxygen exhaust pipe of each PEM electrolyzer, and adjusts the oxygen exhaust pipe pressure regulating valve and the hydrogen exhaust pipe pressure regulating valve so that the gas pipe pressure of the oxygen exhaust pipe of each PEM electrolyzer and the actual gas pipe pressure of the hydrogen exhaust pipe meet the safety pressure relationship. Then the self-check control of the electric hydrogen production system is completed, and the control center controls the oxygen exhaust pipe three-way valve and the hydrogen exhaust pipe three-way valve to connect to the common oxygen storage tank and the common hydrogen storage tank;

[0021] Step 2: Start hydrogen production. During the hydrogen production process, determine whether the gas pipe pressures of the oxygen and hydrogen exhaust pipes of the PEM electrolyzer meet the safety pressure relationship, and use current control and liquid level control to adjust the pipe pressure. After the pipe pressure meets the safety pressure relationship, store oxygen and hydrogen in a conventional oxygen and hydrogen storage device;

[0022] During current control, the oxygen exhaust pipe pressure sensor and the hydrogen exhaust pipe pressure sensor monitor the actual gas pipe pressure of each PEM electrolyzer oxygen exhaust pipe and hydrogen exhaust pipe and transmit it back to the control center. When the actual gas pipe pressure meets the safety pressure relationship, the control center controls the oxygen exhaust pipe three-way valve and the hydrogen exhaust pipe three-way valve to connect to the common oxygen storage tank and the common hydrogen storage tank. When the actual gas pipe pressure does not meet the safety pressure relationship, the actual oxygen production rate and hydrogen production rate of the corresponding PEM electrolyzer are calculated by real-time current to obtain the relationship between the real-time current and the actual gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe. The control center changes the real-time current input to each PEM electrolyzer within a reasonable hydrogen production efficiency range through PID control, controls the gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe according to the real-time current, and adjusts the oxygen exhaust pipe pressure regulating valve and the hydrogen exhaust pipe pressure regulating valve for auxiliary regulation, so that the gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe meets the safety pressure relationship.

[0023] In the liquid level control, the oxygen exhaust pipe pressure sensor and the hydrogen exhaust pipe pressure sensor obtain the actual gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe of the PEM electrolyzer, and the oxygen side pressure type liquid level sensor and the hydrogen side pressure type liquid level sensor obtain 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 safety 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 pressure type liquid level sensor is controlled by the control center to adjust the liquid level of the oxygen side gas-liquid separator and the hydrogen side gas-liquid separator according to the difference between the actual liquid level difference and the preset liquid level difference, and the oxygen exhaust pipe pressure regulating valve and the hydrogen exhaust pipe pressure regulating valve are assisted to adjust the pipeline pressure balance so that the gas pipe pressures of the oxygen exhaust pipe and the hydrogen exhaust pipe meet the safety pressure relationship;

[0024] Step 3: Set the emergency control mode. When the pipe pressure balance device detects that the gas pipe pressure of the oxygen exhaust pipe or hydrogen exhaust pipe of the PEM electrolyzer exceeds the preset pipe pressure standard deviation, the control center controls the three-way valve and the main pipeline to close, connect the backup oxygen storage tank and the backup hydrogen storage tank, disconnect the input circuit of the PEM electrolyzer, and re-perform self-check control after the maintenance is completed;

[0025] In the emergency control mode, when the oxygen exhaust pipe pressure sensor and the hydrogen exhaust pipe pressure sensor detect that the gas pipe pressure of a PEM electrolyzer oxygen exhaust pipe or hydrogen exhaust pipe exceeds the threshold value from the preset pipe pressure standard deviation, that is, the gas pipe pressure difference of the PEM electrolyzer oxygen exhaust pipe or hydrogen exhaust pipe is much larger than the adjustable pipe pressure difference within the safety range, and cannot be adjusted by the second control and third control methods, the control center will control the oxygen exhaust pipe three-way valve and the hydrogen exhaust pipe three-way valve of the faulty PEM electrolyzer to close them to the main pipeline and connect them to the spare oxygen storage tank and the spare 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 that, after the self-test control meets the requirements, the oxygen exhaust pipe three-way valve and the hydrogen exhaust pipe three-way valve are re-controlled to connect to the main output gas pipeline.

[0026] The beneficial effect of adopting the above technical solution is that in addition to considering the pressure balance on the hydrogen side and the oxygen side of a single PEM electrolyzer, the pipeline pressure balance on the same side of the gas produced by multiple PEM electrolyzers is still considered, preventing the pressure difference in the parallel pipeline caused by the different working states of each PEM electrolyzer when multiple electrolyzers are working at the same time, thereby avoiding the risk of gas mixing caused by backflow.

[0027] Compared with the prior art, the technical solution proposed by the present invention makes up for the deficiency of not considering the pressure balance of the gas pipeline on the same side in the large-capacity PEM electrolyzer, which not only improves the safety of the system, but also ensures the purity and efficiency of the gas, making the large-capacity PEM electrolyzer more reliable and efficient in practical applications. Through this improvement, the technical solution effectively fills the gap in the prior art and provides a more complete solution. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0030] Figure 3 It is a main flow chart provided by an embodiment of the present invention;

[0031] Figure 4 is a self-check flow chart provided by an embodiment of the present invention;

[0032] Figure 5 is a current control flow chart provided by an embodiment of the present invention;

[0033] Figure 6 is a flow chart of liquid level control provided by an embodiment of the present invention;

[0034] In the figure: 1. step-down transformer; 2. inverter; 3. electric switch; 4. water pump; 5. water purification device; 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 pipe 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 Pressure type liquid level sensor; 19. Oxygen exhaust pipe pressure regulating valve; 20. Hydrogen exhaust pipe pressure regulating valve; 21. Oxygen exhaust pipe pressure sensor; 22. Hydrogen exhaust pipe pressure sensor; 23. Oxygen exhaust pipe three-way valve; 24. Hydrogen exhaust pipe three-way valve; 25. Spare oxygen storage tank; 26. Oxygen dryer; 27. Oxygen buffer; 28. Common oxygen storage tank; 29. ​​Spare hydrogen storage tank; 30. Deaerator; 31. Hydrogen dryer; 32. Hydrogen buffer; 33. Common hydrogen storage tank. DETAILED DESCRIPTION

[0035] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0036] In the process of water electrolysis, water is decomposed into oxygen, hydrogen ions and electrons at the anode, and the hydrogen ions enter the cathode through the proton exchange membrane. Electrons flow out of the anode, pass through the power circuit to the cathode, and the power supply provides driving force. On the cathode side, two protons and electrons recombine to produce hydrogen. In the electrolysis device with multiple electrolyzers, in order to save materials, the hydrogen exhaust pipeline of each electrolyzer is finally connected into one pipeline and then transported to the hydrogen storage device, and the oxygen exhaust pipeline is finally connected into one pipeline and then transported to the oxygen storage device. When the power grid fluctuates greatly, the gas production may change drastically at any time, and the pressure and liquid level control lag will occur, resulting in pressure and liquid level fluctuations exceeding the safety margin and causing safety risks. Therefore, in each transmission pipeline, it is necessary to keep the gas pressure of each pipeline the same, so as to avoid the pressure difference between different pipelines causing hydrogen or oxygen to flow back into the electrolyzer, causing the safety risk of the hydrogen production system to exceed the safety threshold and cause the safety risk of the hydrogen production system.

[0037] In this example, a large-capacity electric hydrogen production system, such as Figure 1As shown, it includes a power supply device Ⅰ, a water supply device Ⅱ, a front-end pipe pressure balancing device Ⅲ, a hydrogen production device 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 device Ⅰ is connected to the power grid, and the other end is connected to the hydrogen production device Ⅳ through the front-end pipe pressure balancing device Ⅲ, which is used to supply power to the electric hydrogen production system; the hydrogen production device Ⅳ is connected to the gas-liquid separation device Ⅴ, which is used to electrolyze 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 through the rear-end pipe pressure balancing device Ⅵ, which is used to separate the liquid in the oxygen and hydrogen; the oxygen storage device Ⅷ stores the oxygen produced by the hydrogen production device Ⅳ, and stores The hydrogen device IX stores the hydrogen produced by the hydrogen production device IV; the front-end pipe pressure balancing device III is connected to the power supply device I and the hydrogen production device IV, and the rear-end pipe pressure balancing device VI is connected to the gas-liquid separation device V, the oxygen storage device VIII and the hydrogen storage device IX. The front-end pipe pressure balancing device III and the rear-end pipe pressure balancing device VI are used to monitor the real-time current change, the actual gas pipe pressure and the actual liquid level of the electric hydrogen production system in real time, and control the hydrogen production device IV to balance the gas pipe pressures of each oxygen exhaust pipe and hydrogen exhaust pipe; the water supply device II is connected to the hydrogen production device IV to supply water to the hydrogen production device IV; the heat conversion device VII is connected to the hydrogen production device IV to cool the hydrogen production device IV and recover waste heat to heat the water supplied to the hydrogen production device IV;

[0038] like Figure 2 As shown, the power supply device I includes a step-down transformer 1, an inverter 2 and an electric 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 PEM electrolyzers 14 of the same model; the gas-liquid separation device V includes an oxygen side gas-liquid separator 15 and a hydrogen side gas-liquid separator 16; 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 exhaust pipe pressure regulating valve 19, a hydrogen exhaust pipe pressure regulating valve 20, an oxygen exhaust pipe pressure sensor 21, a hydrogen exhaust pipe pressure sensor 22, an oxygen exhaust pipe three-way valve 23 and a hydrogen exhaust 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 common 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 common hydrogen storage tank 33;

[0039] One end of the step-down transformer 1 in the power supply device I 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 tube voltage balancing device III to control the switch of the electric hydrogen production system;

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

[0041] The control center 10 in the front-end pipe pressure balancing device III 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] The water pipeline switch 13 in the hydrogen production device IV is connected to the PEM electrolyzer 14, and the PEM electrolyzer 14 is respectively connected to the oxygen side gas-liquid separator 15 and the hydrogen side gas-liquid separator 16 of the gas-liquid separation device V; the oxygen side gas-liquid separator 15 and the hydrogen side gas-liquid separator 16 in the gas-liquid separation device V are respectively connected to the oxygen storage device VIII and the hydrogen storage device IX through the rear end pipe pressure balance device VI;

[0043] The rear-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-pipeline connected between the oxygen side gas-liquid separator 15 and the oxygen exhaust pipe three-way valve 23. The air inlet valve port of the oxygen exhaust pipe three-way valve 23 is connected to the oxygen exhaust pipe outlet port of the oxygen side gas-liquid separator 15 in the gas-liquid separation device V, and the two air outlet valve ports 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 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-pipeline connected between the hydrogen side pressure level sensor 18 and the hydrogen discharge pipe three-way valve 24 in the gas-liquid separation device V, and the gas inlet valve port of the hydrogen discharge pipe three-way valve 24 is connected to the hydrogen discharge pipe gas outlet port of the hydrogen side gas-liquid separator 16 in the gas-liquid separation device V, and the two gas outlet valve ports of the hydrogen discharge pipe three-way valve 24 are connected to the spare hydrogen storage tank 29 and the gas inlet port of the deaerator 30 in the hydrogen storage device IX;

[0044] The air inlet of the standby oxygen storage tank 25 in the oxygen storage device VIII is connected to one of the air outlet valves of the oxygen exhaust pipe three-way valve 23, the air inlet of the oxygen dryer 26 is connected to the other air outlet valve of the oxygen pipe three-way valve 23, the air outlet of the oxygen dryer 26 is connected to the air inlet of the oxygen buffer 27, and the air outlet of the oxygen buffer 27 is connected to the air inlet of the common oxygen storage tank 28;

[0045] The air inlet of the standby hydrogen storage tank 29 in the hydrogen storage device IX is connected to one of the outlet valves of the hydrogen discharge pipe three-way valve 24, the air inlet of the deaerator 30 is connected to the other outlet valve of the hydrogen discharge pipe three-way valve 24, the air outlet of the deaerator 30 is connected to the air inlet of the hydrogen dryer 31, the hydrogen dryer 31 is connected to the air inlet of the hydrogen buffer 32, and the air outlet of the hydrogen buffer 32 is connected to the air inlet of the common hydrogen storage tank 33;

[0046] The water pump 4 in the water supply device II is used to provide a water source for the hydrogen production device IV, the water purification device 5 is used to purify the water provided by the water pump 4 to obtain purified water to meet the water use standard of the electrolysis device, and the purified water tank 6 is used to store purified water to avoid damage to the PEM electrolyzer 14 in the hydrogen production device IV due to sudden lack of water supply during operation, and at the same time ensure that the PEM electrolyzer 14 in the hydrogen production device IV can be smoothly shut down when there is no water supply; the 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, and the purified water in the purified water tank 6 is extracted to supply water to the hydrogen production device IV, and the high-conductivity purified water and the low-conductivity purified water are separated by the ion filter 8, and the conductivity of the purified water flowing into the hydrogen production device IV is controlled to meet the operation requirements of the PEM electrolyzer 14, and the temperature controller 9 controls the temperature of the purified water entering the hydrogen production device IV from the water supply device II so that it can meet the electrolysis water temperature of the hydrogen production device IV;

[0047] The control center 10 and the current sensor 11 in the front-end pipe pressure balancing device III, the oxygen side pressure type liquid level sensor 17, the hydrogen side pressure type liquid level sensor 18, the oxygen exhaust pipe pressure regulating valve 19, the hydrogen exhaust pipe pressure regulating valve 20, the oxygen exhaust pipe pressure sensor 21, the hydrogen exhaust pipe pressure sensor 22, the oxygen exhaust pipe three-way valve 23 and the hydrogen exhaust pipe three-way valve 24 in the rear-end pipe pressure balancing device VI are connected through electrical signals, the current sensor 11 is used to monitor the real-time current change of each PEM electrolyzer 14 in real time, the oxygen side pressure type liquid level sensor 17 and the hydrogen side pressure type liquid 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 the hydrogen exhaust pipe pressure sensor 22 are used to monitor the actual gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe of the PEM electrolyzer 14 in real time, and the actual speed of oxygen production and hydrogen production The control center 10 controls the switch of the current switch 12, adjusts the input current value and the liquid level of the gas-liquid separation device, and controls the opening of the oxygen exhaust pipe pressure regulating valve 19 and the hydrogen exhaust pipe pressure regulating valve 20 to ensure the liquid level balance 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 data adjustment of the above large-capacity electric hydrogen production system; the oxygen exhaust pipe three-way valve 23 and the hydrogen exhaust pipe three-way valve 24 are used to control the flow direction of the gas. When a certain PEM electrolyzer fails, the gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe of the PEM electrolyzer changes dramatically and affects the pressure of the entire gas pipeline. The control center 10 adjusts the oxygen exhaust pipe three-way valve 23 and the hydrogen exhaust pipe three-way valve 24 to disconnect the sub-gas pipeline from the total gas pipeline, ensuring that the remaining PEM electrolyzers can continue to work safely;

[0048] The oxygen side pressure type liquid level sensor 17 and the hydrogen side pressure type liquid level sensor 18 obtain the actual liquid level of the oxygen side gas-liquid separator 15 and the hydrogen side gas-liquid separator 16 of each PEM electrolyzer, calculate the difference between the actual liquid level on the oxygen side and the actual liquid level on the hydrogen side and the preset liquid level on the oxygen side and the preset liquid level on the hydrogen side, and adjust the liquid level of the oxygen side gas-liquid separator 15 and the hydrogen side gas-liquid separator 16 according to the difference between the actual liquid level and the preset liquid level, and control the pressure type liquid level sensor 14 through the control center 10, and assist in adjusting the oxygen exhaust pipe pressure regulating valve 19 and the hydrogen exhaust pipe pressure regulating valve 20 to ensure the accuracy of the adjustment of the oxygen exhaust pipe pressure regulating valve 19 and the hydrogen exhaust pipe pressure regulating valve 20, so as to balance the liquid levels on both sides of the hydrogen production equipment and ensure the accuracy of the calculated actual liquid level difference between the oxygen side and the hydrogen side.

[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, prevent the gas from entering the liquid pipeline or the liquid from entering the gas pipeline, and 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 self-test, the oxygen dryer 26 is used to absorb water vapor in the oxygen separated by the oxygen-side gas-liquid separator 15, and the oxygen buffer 27 is used to absorb the impact force of oxygen;

[0051] The deaerator 30 in the hydrogen storage device IX is used to remove a small amount of oxygen that may be mixed in the hydrogen to improve the purity of the hydrogen, the hydrogen dryer 31 is used to absorb water vapor in the hydrogen separated by the hydrogen-side gas-liquid separator 16, and 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 the hydrogen exhaust pipe pressure sensor 22 in the rear-end pipe pressure balancing device VI obtain the actual gas pipe pressure of the oxygen exhaust pipe and the gas pipe pressure of the hydrogen exhaust pipe of the four PEM electrolyzers 14, and the current sensor 11 monitors the real-time current of each PEM electrolyzer. When the gas pipe pressure does not meet the safety pressure relationship, the real-time current is compared with the preset current to ensure the accuracy of the comparison result. And within the reasonable hydrogen production efficiency range, the real-time current of the PEM electrolyzer 14 is adjusted by the control center 10 to control the hydrogen production rate and oxygen production rate, thereby adjusting the gas pipe pressure of the pipeline. The actual hydrogen production rate and oxygen production rate are calculated according to the real-time current, and the gas pipe pressures of the oxygen exhaust pipe and the hydrogen exhaust pipe are controlled according to the change in the gas production rate. The oxygen exhaust pipe pressure regulating valve 19 and the hydrogen exhaust pipe pressure regulating valve 20 are used for auxiliary regulation, so that the gas pipe pressures of the oxygen exhaust pipe and the hydrogen exhaust pipe are within the safety threshold, thereby avoiding the excessive difference in the gas pipe pressures of the hydrogen exhaust pipe of the hydrogen production equipment, which may cause oxygen to flow back into the hydrogen production device and mix with hydrogen to cause explosion;

[0053] In this example, a control method for a large-capacity electric hydrogen production system is provided. Figure 3 As shown, the following steps are included:

[0054] Step 1: Use the self-checking control mode (first control mode) to perform self-checking of the large-capacity electric hydrogen production system, such as Figure 4 As shown, the pipe pressure balancing device is started and a preset current is passed into the PEM electrolyzer, and the pipeline pressure regulating valve is adjusted to balance the gas pipe pressures of the oxygen exhaust pipe and the hydrogen exhaust pipe of the PEM electrolyzer and meet the safety pipe pressure relationship;

[0055] First, all the three-way valves 23 of the oxygen discharge pipe and the three-way valves 24 of the hydrogen discharge pipe are connected to the spare oxygen storage tank 25 and the spare hydrogen storage tank 29. The oxygen side pressure type liquid level sensor 17 and the hydrogen side pressure type liquid level sensor 18 obtain the actual liquid level of the oxygen side gas-liquid separator 15 and the hydrogen side gas-liquid separator 16, and judge whether the actual liquid level is at the preset liquid level. If not, the liquid level is adjusted by the oxygen side pressure type liquid level sensor 17 and the hydrogen side pressure type liquid level sensor 18 of the control center 10. After the preset liquid level is met, the pipe pressure balancing device IV is started, and all A preset current is passed through the PEM electrolyzer 14. When the PEM electrolyzer 14 runs smoothly, the pipe pressure balancing device IV monitors the actual gas pipe pressure of the oxygen exhaust pipe of each PEM electrolyzer 14, and adjusts the oxygen exhaust pipe pressure regulating valve 19 and the hydrogen exhaust pipe pressure regulating valve 20 so that the gas pipe pressure of the oxygen exhaust pipe of each PEM electrolyzer and the actual gas pipe pressure of the hydrogen exhaust pipe meet the safety pressure relationship. Then, the self-check control of the electric hydrogen production system is completed, and 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 common oxygen storage tank 28 and the common hydrogen storage tank 33;

[0056] The safety pressure relationship that the oxygen exhaust pipe gas pipe pressure needs to meet is shown in the following formula:

[0057]

[0058] in, is the actual gas pipe pressure of the oxygen exhaust pipe of the kth PEM electrolyzer, k is the serial number of the PEM electrolyzer, and in this embodiment, k is 1, 2, 3, 4, is the target gas pipe pressure of the oxygen exhaust pipe of the PEM electrolyzer, P1 is the first safety pipe pressure difference, and in this embodiment, the target gas pipe pressure of the oxygen exhaust pipe is set to The average value of the target gas pipe pressure of the oxygen exhaust pipe of each PEM electrolyzer;

[0059] The target gas pipe pressure of the oxygen exhaust pipe of the PEM electrolyzer The calculation formula is as follows:

[0060]

[0061] The safety pressure relationship that the gas pipe pressure of the hydrogen exhaust pipe needs to meet is shown in the following formula:

[0062]

[0063] in, is the actual gas pipe pressure of the hydrogen discharge pipe of the kth PEM electrolyzer, is the target gas pipe pressure of the hydrogen discharge pipe of the PEM electrolyzer, P2 is the second safety pipe pressure difference, which is set to the average value of the target gas pipe pressure of the hydrogen discharge pipe of each PEM electrolyzer in this embodiment;

[0064] The gas pressure of the hydrogen exhaust pipe target pipe of the PEM electrolyzer The calculation formula is as follows:

[0065]

[0066] Assume that the lengths of all oxygen exhaust pipes and hydrogen exhaust pipes are the same. The pressure difference of the first safety pipe and the pressure difference of the second safety pipe are calculated according to the Hagen-Bose equation. The calculation formula of the pressure difference of the first safety pipe is as follows:

[0067]

[0068] in, is the radius of the oxygen exhaust pipe, is the viscosity of oxygen, is the length of the oxygen exhaust pipe, is the average flow rate of the oxygen exhaust pipe; the pressure difference calculation formula of the second safety pipe is as follows:

[0069]

[0070] in, is the radius of the hydrogen discharge pipe, is the viscosity of hydrogen, is the length of the hydrogen discharge pipe, is the average flow rate of the hydrogen discharge pipe;

[0071] Step 2: Start hydrogen production. During the hydrogen production process, determine whether the gas pipe pressures of the oxygen exhaust pipe and the hydrogen exhaust pipe of the PEM electrolyzer meet the safety pressure relationship, and use current control (the second control method) and liquid level control (the third control method) to adjust the pipe pressure. After the pipe pressure meets the safety pressure relationship, store oxygen and hydrogen in a conventional oxygen and hydrogen storage device;

[0072] In the current control (second control mode), if Figure 5As shown, the oxygen exhaust pipe pressure sensor 21 and the hydrogen exhaust pipe pressure sensor 22 monitor the actual gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe of each PEM electrolyzer 14 and transmit it back to the control center 10. When the actual gas pipe pressure meets the safety 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 common oxygen storage tank 28 and the common hydrogen storage tank 33. When the actual gas pipe pressure does not meet the safety pressure relationship, the actual oxygen production rate and hydrogen production rate of the corresponding PEM electrolyzer 14 are calculated by real-time current, and the real-time current and the oxygen exhaust pipe and exhaust pipe pressure are obtained. The control center 12 changes the real-time current input to each PEM electrolyzer 14 within a reasonable hydrogen production efficiency range through PID control, controls the gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe according to the real-time current, and adjusts the oxygen exhaust pipe pressure regulating valve 19 and the hydrogen exhaust pipe pressure regulating valve 20 for auxiliary adjustment at the same time, so that the gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe meets the safety pressure relationship; thereby avoiding the excessive difference in the pipe pressure on the oxygen side of the hydrogen production equipment, which may cause the oxygen to flow back into the hydrogen production device and mix with the hydrogen to cause an explosion;

[0073] According to the Ferrari principle, the actual oxygen production rate and hydrogen production rate of the PEM electrolyzer under working conditions are calculated. The calculation formula is as follows:

[0074]

[0075] in, is the actual oxygen production rate of the kth PEM electrolyzer under working conditions (mol / s), is the actual hydrogen production rate (mol / s) of the kth PEM electrolyzer under working conditions, n is the number of PEM electrolyzers connected in series, in this embodiment n is 4, k is the real-time current of the kth PEM electrolyzer, F is the Ferrari constant, η F for Ferrari efficiency;

[0076] The calculation formula for the actual oxygen flow rate generated by each PEM electrolyzer under working conditions is as follows:

[0077]

[0078] in, is the actual oxygen flow rate produced by the kth PEM electrolyzer under working conditions (L / s), is the cross-sectional area of ​​the oxygen exhaust pipe, and the PEM electrolyzer takes the same cross-sectional area;

[0079] According to the ideal gas state equation, the actual gas flow rate under working conditions is converted to the gas flow rate under standard conditions. The calculation formula is as follows:

[0080]

[0081] Among them, P1 is the working pressure, P0 is the standard atmospheric pressure, T1 is the working temperature of the electrolyzer, T0 is the absolute temperature under standard conditions, Q1 is the actual gas flow under working conditions, and Q0 is the gas flow under standard conditions;

[0082] The actual oxygen flow rate generated by each PEM electrolyzer under working conditions is converted to the oxygen flow rate generated by each PEM electrolyzer under standard conditions through the ideal gas state equation. The calculation formula is as follows:

[0083]

[0084] in, is the oxygen flow rate (L / s) produced by the kth PEM electrolyzer under standard conditions;

[0085] The calculation formula for the actual hydrogen flow rate generated by each PEM electrolyzer under working conditions is as follows:

[0086]

[0087] in, is the actual hydrogen flow rate (L / s) produced by the kth PEM electrolyzer under working conditions, is the cross-sectional area of ​​the hydrogen discharge pipe;

[0088] The actual hydrogen flow rate produced by each PEM electrolyzer under working conditions is converted to the hydrogen flow rate (L / s) produced by each PEM electrolyzer under standard conditions through the ideal gas state equation. The calculation formula is as follows:

[0089]

[0090] in, is the hydrogen flow rate (L / s) produced by the kth PEM electrolyzer under standard conditions;

[0091] Calculate the mathematical relationship between the real-time current on the oxygen side and the hydrogen side under working conditions and the actual gas pipeline pressure;

[0092] On the oxygen side, under working conditions, the actual gas pipe pressure of each PEM electrolyzer oxygen exhaust pipe satisfies the following formula:

[0093]

[0094] Where R is the gas constant;

[0095] The mathematical relationship between the real-time current of the PEM electrolyzer and the actual gas pipeline pressure of the PEM electrolyzer oxygen exhaust pipe under the corresponding working conditions is shown in the following formula:

[0096]

[0097] On the hydrogen side, under working conditions, the actual gas pipe pressure of each PEM electrolyzer hydrogen discharge pipe satisfies the following formula:

[0098]

[0099] The mathematical relationship between the real-time current of the PEM electrolyzer and the actual gas pipeline pressure of the hydrogen discharge pipe of the PEM electrolyzer under working conditions is shown in the following formula:

[0100]

[0101] The control center 10 calculates the corresponding control signal through PID control. The control signal is used to adjust the input current of the electrolyzer and continuously correct the pressure of the oxygen pipeline to stabilize it near the target value, thereby realizing automatic adjustment and stable operation of the system; the PID controller uses three parts: proportional (P), integral (I) and differential (D) to adjust the deviation, among which proportional control makes an immediate response according to the current deviation, integral control eliminates long-term deviation, and differential control predicts the change trend of the deviation. According to the PID control principle, the PID control formula is as follows:

[0102]

[0103] e(t)=PP(t)

[0104] Where c(t) is the control signal input to the control center; t is time; k p is the proportional gain parameter; ki is the integral gain parameter; kd is the differential gain parameter; e(t) is the current error; P is the target value; P(t) is the actual value;

[0105] The PID control formula is transformed and substituted into the PID control formula for the oxygen side and the hydrogen side;

[0106] The PID control formula for the oxygen side is as follows:

[0107]

[0108] in, is the oxygen side control signal, is the proportional gain parameter on the oxygen side; is the oxygen side integral gain parameter; is the oxygen side differential gain parameter; It is the oxygen pipeline error; It is the instantaneous value of the target gas pipe pressure of the oxygen exhaust pipe under standard conditions; It is the instantaneous value of the actual gas pipe pressure of the oxygen exhaust pipe under standard conditions;

[0109] The PID control formula for the hydrogen side is as follows:

[0110]

[0111] in, is the oxygen side control signal, is the proportional gain parameter on the hydrogen side; is the integral gain parameter on the hydrogen side; is the differential gain parameter on the hydrogen side; is the hydrogen pipeline error; is the instantaneous value of the target gas pipe pressure of the hydrogen exhaust pipe under standard conditions; It is the instantaneous value of the actual gas pipe pressure of the hydrogen exhaust pipe under standard conditions;

[0112] In the liquid level control (third control mode), if Figure 6 As shown, the oxygen exhaust pipe pressure sensor 21 and the hydrogen exhaust pipe pressure sensor 22 obtain the actual gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe of the PEM electrolyzer 14, and the oxygen side pressure type liquid level sensor 17 and the hydrogen side pressure type liquid level sensor 18 obtain the actual liquid level 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 safety 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 pressure type liquid level is controlled by the control center 10 according to the difference between the actual liquid level difference and the preset liquid level difference. The sensor 14 is used to adjust the liquid level of the oxygen-side gas-liquid separator 15 and the hydrogen-side gas-liquid separator 16, and the oxygen-discharge pipe pressure regulating valve 19 and the hydrogen-discharge pipe pressure regulating valve 20 are assisted in adjusting the pipeline pressure balance so that the gas pipe pressures of the oxygen-discharge pipe and the hydrogen-discharge pipe meet the safety pressure relationship; the liquid level control ensures the accuracy of the adjustment of the oxygen-discharge pipe pressure regulating valve 19 and the hydrogen-discharge pipe pressure regulating valve 20 of the oxygen-discharge pipe and the hydrogen-discharge pipe, so that the liquid level of each pipeline on the oxygen side of the hydrogen production device IV and the liquid level of each pipeline on the hydrogen side can be balanced, so that the gas pipe pressures of oxygen and hydrogen meet the safety pressure relationship. This avoids the excessive difference in pipe pressure on the oxygen side of the hydrogen production equipment, which may cause oxygen to flow back into the hydrogen production device and mix with hydrogen to cause an explosion;

[0113] In this embodiment, the second control mode and the third control mode can be used in combination;

[0114] Step 3: Set the emergency control mode (the fourth control mode). When the pipe pressure balancing device detects that the gas pipe pressure of the oxygen exhaust pipe or hydrogen exhaust pipe of the PEM electrolyzer exceeds the preset pipe pressure standard deviation, the control center controls the three-way valve and the main pipeline to close, connect the backup oxygen storage tank and the backup hydrogen storage tank, disconnect the input circuit of the PEM electrolyzer, and re-perform self-check control after the maintenance is completed;

[0115] In the emergency control mode, when the oxygen exhaust pipe pressure sensor 21 and the hydrogen exhaust pipe pressure sensor 22 detect that the gas pipe pressure of a certain PEM electrolyzer oxygen exhaust pipe or hydrogen exhaust pipe exceeds the preset pipe pressure standard deviation, that is, the gas pipe pressure difference of the PEM electrolyzer oxygen exhaust pipe or hydrogen exhaust pipe is much greater than the adjustable pipe pressure difference within the safety range, and cannot be adjusted by the second control and third control methods, the control center 10 will control the oxygen exhaust pipe three-way valve 23 and the hydrogen exhaust pipe three-way valve 24 of the faulty PEM electrolyzer to close them to the main pipeline and connect them to the spare oxygen storage tank 25 and the spare hydrogen storage tank 29. At this time, the control center 10 controls the current switch 12 of the faulty PEM electrolyzer to be disconnected, and the PEM electrolyzer enters maintenance. After that, after the self-test control meets the requirements, the oxygen exhaust pipe three-way valve 23 and the hydrogen exhaust pipe three-way valve 24 are re-controlled to connect to the main output gas pipeline.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements 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. A large-capacity electric hydrogen production system, characterized by: It includes 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 and a hydrogen storage device; 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 the front-end pipe pressure balancing device, so as to supply power to the electric hydrogen production system; the hydrogen production device is connected to the gas-liquid separation device, so as to electrolyze water to produce oxygen and hydrogen; The gas-liquid separation device is connected with the oxygen storage device and the hydrogen storage device through the rear-end pipe pressure balancing device, and is used for separating the liquid in 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 with the power supply device and the hydrogen production device, and the rear-end pipe pressure balancing device is connected with the gas-liquid separation device, the oxygen storage device and the hydrogen storage device. The front-end pipe pressure balancing device and the rear-end pipe pressure balancing device are used for real-time monitoring of the real-time current change, the actual gas pipe pressure and the actual liquid level of the electric hydrogen production system, and controlling the hydrogen production device to balance the gas pipe pressures of each oxygen exhaust pipe and hydrogen exhaust pipe; the water supply device is connected with the hydrogen production device to supply water to the hydrogen production device; the heat conversion device is connected with the hydrogen production device to cool the hydrogen production device and recover waste heat to heat the water supplied to the hydrogen production device.

2. A large-capacity electric 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 tube voltage balancing device; The water supply device comprises a water pump, a water purification device, a purified water tank, a purified water pump, an ion filter and a temperature controller; the water outlet of the water pump is connected to the water inlet of the water purification device, the water outlet of the water purification device is connected to the water inlet of the purified water tank, the water outlet of the purified water tank is connected to the water inlet of the purified water pump, the water outlet of the purified water pump is connected to the water inlet of the ion filter, and the water outlet of the ion filter is connected to the hydrogen production device through the temperature controller; the water pump is used to provide a water source for the hydrogen production device, the water purification device is used to purify the water provided by the water pump to obtain purified water, and the purified water tank is used to store purified water; the purified water pump draws purified water from the purified water tank to supply water to the hydrogen production device, and controls the conductivity of the purified water flowing into the hydrogen production device through the ion filter to meet the operation requirements, and the temperature controller controls the temperature of the purified water entering the hydrogen production device from the water supply device.

3. A large-capacity electric hydrogen production system according to claim 2, characterized in that: The hydrogen production device comprises 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 comprises 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 the 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 generated by the PEM electrolyzer in the hydrogen production device.

4. A large-capacity electric hydrogen production system according to claim 3, characterized in that: 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 is connected to the current sensor through an electrical signal, the current sensor is used to monitor the real-time current change of each PEM electrolyzer in real time, and the control center controls the switch of the current switch, adjusts the input current value and the liquid level of the gas-liquid separation device; The rear-end pipe pressure balancing device comprises 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 rear-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-pipeline connected between the oxygen side gas-liquid separator and the oxygen exhaust pipe three-way valve. The air inlet valve port of the oxygen exhaust pipe three-way valve is connected to the oxygen side gas in the gas-liquid separator device. The gas outlet of the oxygen discharge pipe of the liquid separator is connected, and the two gas outlet valve ports of the three-way valve of the oxygen discharge pipe are connected to the spare oxygen storage tank in the oxygen storage device and the gas inlet of the oxygen dryer; 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-pipeline connected between the hydrogen side gas-liquid separator and the hydrogen discharge pipe three-way valve in the gas-liquid separation device, the gas inlet valve port of the hydrogen discharge pipe three-way valve is connected to the gas outlet of the hydrogen discharge pipe of the hydrogen side gas-liquid separator in the gas-liquid separation device, and the two gas outlet valve ports of the three-way valve of the hydrogen discharge pipe are connected to the spare hydrogen storage tank in the hydrogen storage device and the gas inlet of the deaerator; 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 through 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 opening of the three-way valve and the hydrogen discharge pipe pressure regulating valve is controlled by the control center to ensure the liquid level balance 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 flow direction of the gas. When a PEM electrolyzer fails, the gas pipe pressure of the oxygen discharge pipe and the hydrogen discharge pipe of the PEM electrolyzer changes drastically and affects the pressure of the entire gas pipeline. The control center adjusts the oxygen discharge pipe three-way valve and the hydrogen discharge pipe three-way valve to disconnect the sub-gas pipeline from the main gas pipeline, ensuring that the remaining PEM electrolyzers can continue to work safely.

5. A large-capacity electric hydrogen production system according to claim 4, characterized in that: The oxygen storage device comprises a spare oxygen storage tank, an oxygen dryer, an oxygen buffer and a common oxygen storage tank; the air inlet of the spare oxygen storage tank is connected to an air outlet valve port of the three-way valve of the oxygen exhaust pipe, the air inlet of the oxygen dryer is connected to the other air outlet valve port of the three-way valve of the oxygen exhaust pipe, the air outlet of the oxygen dryer is connected to the air inlet of the oxygen buffer, and the air outlet of the oxygen buffer is connected to the air inlet of the common oxygen storage tank; the spare oxygen storage tank is used to temporarily store oxygen when the electric hydrogen production system performs self-inspection, 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 oxygen; The hydrogen storage device includes a spare hydrogen storage tank, a deaerator, a hydrogen dryer, a hydrogen buffer and a common hydrogen storage tank; the air inlet of the spare hydrogen storage tank is connected to an outlet valve port of the three-way valve of the hydrogen exhaust pipe, the air inlet of the deaerator is connected to the other outlet valve port of the three-way valve of the hydrogen exhaust pipe, the air outlet of the deaerator is connected to the air inlet of the hydrogen dryer, the hydrogen dryer is connected to the air inlet of the hydrogen buffer, and the air outlet of the hydrogen buffer is connected to the air inlet of the common hydrogen storage tank; the deaerator is used to remove oxygen that may be mixed in the hydrogen to improve 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.

6. A control method for a large-capacity electric hydrogen production system, implemented based on the large-capacity electric hydrogen production system according to claim 5, characterized in that: The following steps are involved: Step 1: Use the self-check control method to perform a self-check on the large-capacity electric hydrogen production system, start the pipe pressure balancing device and pass a preset current into the PEM electrolyzer, and adjust the pipeline pressure regulating valve to balance the gas pipe pressure of the PEM electrolyzer oxygen exhaust pipe and hydrogen exhaust pipe and meet the safety pipe pressure relationship; Step 2: Start hydrogen production. During the hydrogen production process, determine whether the gas pipe pressures of the oxygen and hydrogen exhaust pipes of the PEM electrolyzer meet the safety pressure relationship, and use current control and liquid level control to adjust the pipe pressure. After the pipe pressure meets the safety pressure relationship, store 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 PEM electrolyzer oxygen exhaust pipe or hydrogen exhaust pipe exceeds the preset pipe pressure standard deviation, the control center controls the three-way valve and the main pipeline to close, connect with the spare oxygen storage tank and the spare hydrogen storage tank, disconnect the input circuit of the PEM electrolyzer, and re-perform self-inspection control after the maintenance is completed.

7. The control method of a large-capacity electric hydrogen production system according to claim 6 is characterized in that: The specific method of step 1 is: firstly, all the three-way valves of the oxygen discharge pipe and the three-way valve of the hydrogen discharge pipe are connected to the spare oxygen storage tank and the spare hydrogen storage tank, and the oxygen side pressure type liquid level sensor and the hydrogen side pressure type liquid level sensor obtain the actual liquid level of the oxygen side gas-liquid separator and the hydrogen side gas-liquid separator, and judge whether the actual liquid level is at the preset liquid level. If it is not at the preset liquid level, the liquid level is adjusted by the oxygen side pressure type liquid level sensor and the hydrogen side pressure type liquid level sensor of the control center. After the preset liquid level is met, the pipe pressure balancing device is started. The device is set and a preset current is passed through all PEM electrolyzers. When the PEM electrolyzers are running smoothly, the pipe pressure balancing device monitors the actual gas pipe pressure of the oxygen exhaust pipe of each PEM electrolyzer, and adjusts the oxygen exhaust pipe pressure regulating valve and the hydrogen exhaust pipe pressure regulating valve to make the gas pipe pressure of the oxygen exhaust pipe of each PEM electrolyzer and the actual gas pipe pressure of the hydrogen exhaust pipe meet the safety pressure relationship. The self-check control of the hydrogen production system is completed, and the control center controls the oxygen exhaust pipe three-way valve and the hydrogen exhaust pipe three-way valve to connect to the common oxygen storage tank and the common hydrogen storage tank.

8. The control method of a large-capacity electric hydrogen production system according to claim 7 is characterized in that: The specific method of current control in step 2 is as follows: during current control, an oxygen exhaust pipe pressure sensor and a hydrogen exhaust pipe pressure sensor monitor the actual gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe of each PEM electrolyzer and transmit the pressure back to the control center. When the actual gas pipe pressure meets the safety pressure relationship, the control center controls the oxygen exhaust pipe three-way valve and the hydrogen exhaust pipe three-way valve to connect to the common oxygen storage tank and the common hydrogen storage tank. When the actual gas pipe pressure does not meet the safety pressure relationship, the actual oxygen production rate and hydrogen production rate of the corresponding PEM electrolyzer are calculated by real-time current to obtain the relationship between the real-time current and the actual gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe. The control center changes the real-time current input to each PEM electrolyzer within a reasonable hydrogen production efficiency range through PID control, controls the gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe according to the real-time current, and adjusts the oxygen exhaust pipe pressure regulating valve and the hydrogen exhaust pipe pressure regulating valve for auxiliary adjustment, so that the gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe meets the safety pressure relationship.

9. The control method of a large-capacity electric hydrogen production system according to claim 8, characterized in that: The specific method of liquid level control in step 2 is as follows: in liquid level control, the oxygen exhaust pipe pressure sensor and the hydrogen exhaust pipe pressure sensor obtain the actual gas pipe pressure of the oxygen exhaust pipe and the hydrogen exhaust pipe of the PEM electrolyzer, and the oxygen side pressure type liquid level sensor and the hydrogen side pressure type liquid level sensor obtain 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 safety pressure relationship, the actual liquid level value of the hydrogen side or the oxygen side is compared with the preset liquid level, and when the actual liquid level is too different from the preset liquid level, the pressure type liquid level sensor is controlled by the control center to adjust the liquid level of the oxygen side gas-liquid separator and the hydrogen side gas-liquid separator according to the difference between the actual liquid level difference and the preset liquid level difference, and the oxygen exhaust pipe pressure regulating valve and the hydrogen exhaust pipe pressure regulating valve are assisted to adjust the pipeline pressure balance so that the gas pipe pressures of the oxygen exhaust pipe and the hydrogen exhaust pipe meet the safety pressure relationship.

10. The control method of a large-capacity electric hydrogen production system according to claim 9, characterized in that: The specific method of step 3 is: in the emergency control mode, when the oxygen exhaust pipe pressure sensor and the hydrogen exhaust pipe pressure sensor detect that the gas pipe pressure of a certain PEM electrolyzer oxygen exhaust pipe or hydrogen exhaust pipe exceeds the preset pipe pressure standard deviation, that is, the gas pipe pressure difference of the PEM electrolyzer oxygen exhaust pipe or hydrogen exhaust pipe is much greater than the adjustable pipe pressure difference within the safety range, and cannot be adjusted by the second control and the third control methods, the control center will control the oxygen exhaust pipe three-way valve and the hydrogen exhaust pipe three-way valve of the faulty PEM electrolyzer to close them to the main pipeline and connect them to the spare oxygen storage tank and the spare 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 that, after the self-check control meets the requirements, the oxygen exhaust pipe three-way valve and the hydrogen exhaust pipe three-way valve are re-controlled to connect to the main output gas pipeline.

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