PEM water electrolysis hydrogen production system and control method

Abstract

The invention discloses a PEM water electrolysis hydrogen production system and a control method, and belongs to the technical field of electrolysis hydrogen production. The PEM water electrolysis hydrogen production system provided by the invention comprises a water purifier, a temperature control water tank, a circulating water tank, a heat exchanger, an electrolytic bath, a first steam-water separator and a control system, a three-way valve and a first water pump are arranged on a pipeline between the circulating water tank and the heat exchanger; a liquid outlet of the electrolytic bath is communicated with a liquid inlet of the circulating water tank and a liquid inlet of the first steam-water separator through pipelines respectively; an air outlet of the first steam-water separator is communicated with the circulating water tank through a pipeline; a liquid outlet of the circulating water tank, the first water pump and a liquid outlet of the first steam-water separator are communicated with the three-way valve; the control system is used for controlling opening and closing of the first solenoid valve and the second solenoid valve, valve opening of the three-way valve, rotating speed of the first water pump and current of the electrolytic bath. The system can be quickly started, and meanwhile the risk that the electrolytic cell is damaged due to large-current starting is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic hydrogen production, and in particular to a PEM electrolytic water hydrogen production system and a control method. Background Art

[0002] The information disclosed in the background art of the present invention is only intended to increase the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] As the core direction of green hydrogen production, proton exchange membrane (PEM) electrolytic water hydrogen production technology is widely used in scenarios such as renewable energy coupled hydrogen production and industrial hydrogen supply due to its advantages of fast response, high current density, and pure gas production. However, the operational stability and energy efficiency optimization of PEM electrolytic water hydrogen production systems are still the main bottlenecks for their large-scale promotion.

[0004] During the startup phase, the PEM electrolytic water hydrogen production system needs to simultaneously meet the requirements that the temperature at the inlet of the electrolytic cell reaches the standard and the current rises to the set value before the startup is completed. However, in the prior art, this process often takes a long time: on the one hand, the large amount of water in the water tank participating in the circulation needs to flow through the electrolytic cell and be gradually heated, and the large water volume and its heat capacity characteristics result in a slow temperature rise; on the other hand, in order to adapt to the heat dissipation requirements of the electrolytic cell and avoid damage to the precision components of the electrolytic cell caused by large current impact during low-temperature operation, the system usually adopts a small-current startup mode, at which time the heat generation is low, further delaying the heating rate. The superposition of these two factors significantly extends the startup cycle. Therefore, it is necessary to provide a PEM electrolytic water hydrogen production system that can start quickly and operate stably. Summary of the Invention

[0005] In view of this, the present invention provides a PEM electrolytic water hydrogen production system and a control method. The PEM electrolytic water hydrogen production system provided by the present invention can achieve rapid startup and significantly shorten the startup cycle.

[0006] In a first aspect, the present invention provides a PEM electrolytic water hydrogen production system, including a pure water machine, a temperature control water tank, a circulation water tank, a heat exchanger, an electrolytic cell, a first steam-water separator, and a control system; The pure water machine, the temperature control water tank, the circulation water tank, the heat exchanger, and the electrolytic cell are sequentially connected in series through pipelines; a three-way valve and a first water pump are arranged on the pipeline between the circulation water tank and the heat exchanger; The liquid outlet of the electrolytic cell is communicated with the circulation water tank through a pipeline provided with a first electromagnetic valve, and the liquid outlet of the electrolytic cell is communicated with the liquid inlet of the first steam-water separator through a pipeline provided with a second electromagnetic valve; the gas outlet of the first steam-water separator is communicated with the circulation water tank through a pipeline; The liquid outlet of the circulation water tank, the first water pump, and the liquid outlet of the first steam-water separator are communicated with the three-way valve; The control system is used to control the opening and closing of the first solenoid valve and the second solenoid valve, the valve opening of the three-way valve, the rotation speed of the first water pump, and the current of the electrolytic cell.

[0007] Preferably, a third solenoid valve is provided on the pipeline between the pure water machine and the temperature control water tank, and a fourth solenoid valve is provided on the pipeline between the temperature control water tank and the circulation water tank; a heating module is provided in the temperature control water tank, and the heating module is electrically connected to the control system.

[0008] Preferably, it further includes a temperature acquisition unit, a liquid level acquisition unit, and a flow rate acquisition unit. The temperature acquisition unit is used to acquire the temperature values of the temperature control water tank, the circulation water tank, the electrolytic cell inlet, and the electrolytic cell outlet. The liquid level acquisition unit is used to acquire the liquid levels of the temperature control water tank and the circulation water tank. The flow rate acquisition unit is used to acquire the electrolytic cell inlet flow rate.

[0009] Preferably, it further includes a chiller, and the chiller is in cyclic communication with the heat exchanger through a first pipeline and a second pipeline; an electric opening valve is provided on the second pipeline.

[0010] Furthermore, it further includes a heat recovery system. The heat recovery system is connected to the first pipeline through a third pipeline, and a third solenoid valve is provided on the third pipeline; the heat recovery system is connected to the second pipeline between the electric opening valve and the heat exchanger through a fourth pipeline; a second water pump is provided on the fourth pipeline.

[0011] Preferably, it further includes a second steam-water separator, a condenser, and a hydrogen purification system; the second steam-water separator is connected to the gas outlet of the electrolytic cell, the gas outlet end of the second steam-water separator is connected to the condenser, and the condenser is connected to the hydrogen purification system.

[0012] Furthermore, the liquid outlet ends of the second steam-water separator and the condenser are connected to the liquid seal device through a fifth pipeline, and the liquid seal device is connected to the temperature control water tank; a pressure buffer tank is provided on the fifth pipeline.

[0013] Preferably, it further includes an oxygen treatment system, and the oxygen treatment system is connected to the circulation water tank.

[0014] In a second aspect, the present invention provides a control method for the above-mentioned PEM electrolytic water hydrogen production system, including the following steps: When the PEM electrolytic water hydrogen production system is started, the water in the circulation water tank enters the electrolytic cell through the three-way valve. When the water flow rate reaches the idle flow rate, close the first solenoid valve, open the second solenoid valve, and adjust the valve opening of the three-way valve so that the liquid outlet volume of the circulation water tank is 0; gradually increase the current of the electrolytic cell according to the measured value of the electrolytic cell inlet temperature, and adjust the rotation speed of the first water pump according to the current value until the rated current is reached; After the inlet temperature of the electrolytic cell is greater than or equal to the target temperature, open the first solenoid valve and control the valve opening of the three-way valve to gradually increase the liquid output of the circulation water tank and gradually decrease the liquid output of the first steam-water separator. Control the inlet temperature of the electrolytic cell to remain constant until the liquid output of the first steam-water separator is 0, then close the second solenoid valve to reach the stable operation stage.

[0015] Preferably, when the PEM electrolytic water hydrogen production system is started, it also includes adjusting the temperature of the temperature control water tank to reach the preset temperature value and controlling the root mean square error value of the temperature in the temperature control water tank to be less than the preset value; monitoring the liquid level of the circulation water tank, and when the measured liquid level value is lower than the preset liquid level value, controlling the temperature control water tank to replenish water.

[0016] Compared with the prior art, the present invention has achieved the following beneficial effects: (1) The PEM electrolytic water hydrogen production system provided by the present invention realizes the flexible adjustment of the circulation water flow and path through the dynamic switching control of the three-way valve, the first solenoid valve and the second solenoid valve. During startup, the branch circulation of "the first steam-water separator - three-way valve - first water pump - heat exchanger - electrolytic cell - second solenoid valve - first steam-water separator" ensures a rapid increase in temperature. At the same time, the current value of the electrolytic cell is gradually increased through the control system, enabling the system to start quickly, overcoming the disadvantages of starting with a small current and slow heating rate and long startup cycle when heating a large volume of water in the prior art, and also avoiding the risk of damage to the electrolytic cell caused by starting with a large current.

[0017] (2) The present invention forms a closed-loop adjustment mechanism through the linkage control of the opening and closing of the first / second solenoid valves, the opening of the three-way valve, the rotation speed of the first water pump and the current of the electrolytic cell by the control system, combined with the real-time monitoring data of the temperature acquisition unit, the liquid level acquisition unit and the flow acquisition unit, and can dynamically adjust the operating state according to parameters such as temperature, flow and liquid level.

[0018] (3) The present invention further optimizes the heat management ability of the system through the temperature control water tank heating module, the chiller (cooperating with the electric opening valve) and the heat recovery system: the temperature control water tank can pre-adjust the water temperature through the heating module to reduce the impact of low-temperature water replenishment on the temperature of the electrolytic cell; the circulating connection between the chiller and the heat exchanger can adjust the heat dissipation efficiency to avoid energy waste caused by excessive heat dissipation under the rated power; the heat recovery system can recover redundant heat for other processes or the system itself through the connection design of the third pipeline and the fourth pipeline, reduce the operating energy consumption and achieve energy efficiency optimization. Description of the Drawings

[0019] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 is a schematic diagram of the PEM electrolytic water hydrogen production system according to Embodiment 1 of the present invention; Figure 2 is a schematic flow chart of the control method for the rapid start-up of the PEM electrolytic water hydrogen production system according to Embodiment 2 of the present invention; Figure 3 is a schematic flow chart of the control method for the water replenishment process of the PEM electrolytic water hydrogen production system according to Embodiment 2 of the present invention; Figure 4 is a schematic flow chart of the control method for the heat recovery process of the PEM electrolytic water hydrogen production system according to Embodiment 2 of the present invention; In the figure, 1, pure water machine; 2, temperature control water tank; 3, circulation water tank; 4, heat exchanger; 5, electrolytic cell; 6, first steam-water separator; 7, chiller; 8, heat recovery system; 9, three-way valve; 10, first water pump; 11, first temperature sensor; 12, second temperature sensor; 13, third temperature sensor; 14, fourth temperature sensor; 15, fifth temperature sensor; 16, first liquid level sensor; 17, second liquid level sensor; 18, flow sensor; 19, first solenoid valve; 20, second solenoid valve; 21, third solenoid valve; 22, fourth solenoid valve; 23, heating module; 24, oxygen treatment system; 25, first pipeline; 26, second pipeline; 27, fifth solenoid valve; 28, third pipeline; 29, fourth pipeline; 30, second water pump; 31, second steam-water separator; 32, condenser; 33, hydrogen purification system; 34, liquid seal device; 35, fifth pipeline; 36, pressure buffer tank; 37, electric opening valve. Detailed Embodiments

[0021] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0022] Embodiment 1 This embodiment provides a PEM electrolytic water hydrogen production system, as Figure 1As shown in the figure, it includes a pure water machine 1, a temperature control water tank 2, a circulation water tank 3, a heat exchanger 4, an electrolytic cell 5, a first steam-water separator 6, a chiller 7, a heat recovery system 8 and a control system, and also includes a temperature acquisition unit, a liquid level acquisition unit and a flow rate acquisition unit. The pure water machine 1, the temperature control water tank 2, the circulation water tank 3, the heat exchanger 4 and the electrolytic cell 5 are sequentially connected in series through pipelines; a three-way valve 9 and a first water pump 10 are arranged on the pipeline between the circulation water tank 3 and the heat exchanger 4.

[0023] The temperature acquisition unit includes a first temperature sensor 11, a second temperature sensor 12, a third temperature sensor 13, a fourth temperature sensor 14, and a fifth temperature sensor 15, which are respectively used to acquire the temperature values of the temperature control water tank 2, the circulation water tank 3, the liquid inlet of the electrolytic cell 5, the liquid outlet of the electrolytic cell 5, and the heat recovery system 8. The liquid level acquisition unit includes a first liquid level sensor 16 and a second liquid level sensor 17, which are respectively used to acquire the liquid levels of the temperature control water tank 2 and the circulation water tank 3. The flow rate acquisition unit includes a flow rate sensor 18, which is used to acquire the liquid inlet flow rate of the electrolytic cell 5.

[0024] A third solenoid valve 21 is arranged on the pipeline between the pure water machine 1 and the temperature control water tank 2 to control the pure water in the pure water machine 1 to flow to the temperature control water tank 2; a fourth solenoid valve 22 is arranged on the pipeline between the temperature control water tank 2 and the circulation water tank 3 to control the water in the temperature control water tank 2 to enter the circulation water tank 3. A heating module 23 is arranged in the temperature control water tank 2, and the heating module 23 is electrically connected to the control system. The electrical connection between the two is to determine whether heating is required according to the measured temperature value of the temperature control water tank 2, so as to ensure that the water in the temperature control water tank 2 is maintained at a constant temperature during the stable operation process.

[0025] Since the replenishing water temperature output by the pure water machine 1 is usually much lower than the optimal operating temperature range of the electrolytic cell 5, after the low-temperature replenishing water is directly injected into the circulation system, it will be mixed with the medium and lower the inlet temperature of the electrolytic cell 5, resulting in fluctuations in the internal reaction environment. Frequent fluctuations will exacerbate the thermal stress difference between the membrane electrode and the diffusion layer, accelerate the material aging during long-term operation, and shorten the service life of the electrolytic cell 5. Therefore, the present invention sets a temperature control water tank 2 between the pure water machine 1 and the circulation water tank 3 to ensure that the temperature does not fluctuate during the replenishment of water during the stable operation of the electrolytic cell 5, and avoid adverse effects on the electrolytic cell 5.

[0026] The liquid outlet of the electrolytic cell 5 is communicated with the circulation water tank 3 through a pipeline provided with a first solenoid valve 19. The liquid flowing out of the liquid outlet of the electrolytic cell 5 is a mixed liquid of oxygen and water, which directly flows into the circulation water tank 3 through the pipeline where the first solenoid valve 19 is located. The water can be recycled, and the oxygen enters the oxygen treatment system 24 for treatment. The oxygen treatment system 24 is communicated with the circulation water tank 3. When the first solenoid valve 19 is closed, this pipeline is blocked, that is, the mixed liquid flowing out of the liquid outlet of the electrolytic cell 5 does not directly flow into the circulation water tank 3.

[0027] The liquid outlet of the electrolytic cell 5 is connected to the liquid inlet of the first water-gas separator 6 via a pipeline equipped with a second solenoid valve 20. The gas outlet of the first water-gas separator 6 is connected to the circulating water tank 3 via a pipeline. The first water-gas separator 6 separates oxygen and water from the effluent of the electrolytic cell 5. The separated oxygen enters the circulating water tank 3 through the gas outlet and then enters the oxygen treatment system 24 for treatment. The separated water is connected to the three-way valve 9 through the liquid outlet. Because the electrolytic cell 5 continuously produces oxygen during operation, the provision of the first water-gas separator 6 minimizes the adverse effects of oxygen on the pipeline connecting the first water-gas separator 6, the three-way valve 9, the first water pump 10, the heat exchanger 4, and the electrolytic cell 5, such as preventing damage to the pipeline caused by increased air pressure.

[0028] The liquid outlet of the circulating water tank 3, the first water pump 10, and the liquid outlet of the first steam-water separator 6 are connected to the three-way valve 9. Specifically, water flowing out of the liquid outlet of the circulating water tank 3 and the liquid outlet of the first steam-water separator 6 enters the three-way valve 9, flows out of the three-way valve 9, and then enters the first water pump 10. The ratio of the liquid output of the circulating water tank 3 to the liquid output of the first steam-water separator 6 can be controlled by the valve opening of the three-way valve 9. In the prior art, only the circulating water tank 3 and the electrolytic cell 5 are typically connected. Because the amount of water in the circulating water tank 3 is large when the electrolytic cell 5 is heated, it takes a long time for the electrolytic cell 5 to reach the target temperature. The present invention utilizes the continuous self-heating effect of the electrolytic cell 5 during startup, as well as the small water volume branch circuit circulation of "first steam-water separator 6-three-way valve 9-first water pump 10-heat exchanger 4-electrolytic cell 5-second solenoid valve 20-first steam-water separator 6", so that the water temperature entering the electrolytic cell 5 quickly reaches the target temperature, completing the heating process. Since the electrolytic cell 5 continuously generates heat during operation, which causes the water temperature in the branch circuit circulation to be higher than the target temperature, the three-way valve 9 can be adjusted to gradually increase the liquid output of the circulating water tank 3 and gradually decrease the liquid output of the first steam-water separator 6 until it drops to 0. As a result, during the stable operation stage, only the main circuit "circulating water tank 3-three-way valve 9-first water pump 10-heat exchanger 4-electrolytic cell 5-first solenoid valve 19-circulating water tank 3" is retained.

[0029] The control system is used to control the opening and closing of the first solenoid valve 19 and the second solenoid valve 20, the valve opening of the three-way valve 9, the speed of the first water pump 10 and the current of the electrolytic cell 5. The control system is further preferably a PID controller.

[0030] After the system is boosted to rated power operation and the temperature of the circulation water tank 3 is consistent with the liquid outlet temperature of the electrolyzer 5, the heat generated by the electrolyzer 5 still continuously increases, so the requirement for heat dissipation is relatively high. In traditional designs, a heat exchange device is usually set up for heat dissipation, and the heat is not fully utilized. In the present invention, the chiller 7 is circularly communicated with the heat exchanger 4 through the first pipeline 25 and the second pipeline 26; an electric opening valve 37 is arranged on the second pipeline 26. The heat recovery system 8 is communicated with the first pipeline 25 through the third pipeline 28, and a fifth solenoid valve 27 is arranged on the third pipeline 28; the heat recovery system 8 is communicated with the second pipeline 26 between the electric opening valve 37 and the heat exchanger 4 through the fourth pipeline 29; a second water pump 30 is arranged on the fourth pipeline 29. When the temperature of the heat recovery system 8 is lower than the liquid inlet temperature of the electrolyzer 5, the chiller 7 is adjusted to the standby state, the electric opening valve 37 is closed, and the water in the heat recovery system 8 is communicated with the heat exchanger 4, so as to reduce the liquid inlet temperature of the electrolyzer 5 and recover the heat. When the temperature of the heat recovery system 8 is above the liquid inlet temperature of the electrolyzer 5, the second water pump 30 and the fifth solenoid valve 27 are closed, the working state of the chiller 7 is started, the electric opening valve 37 is adjusted, and the chiller 7 is used to cool and dissipate the heat of the liquid inlet of the electrolyzer 5.

[0031] The PEM electrolytic water hydrogen production system of the present invention further includes a second steam-water separator 31, a condenser 32 and a hydrogen purification system 33; the second steam-water separator 31 is communicated with the gas outlet of the electrolyzer 5, and the preliminary separation of hydrogen and water is realized through the second steam-water separator 31. The gas outlet end of the second steam-water separator 31 is communicated with the condenser 32, the condenser 32 is communicated with the hydrogen purification system 33, the condenser 32 further removes the moisture in the inlet gas, and then the hydrogen enters the hydrogen purification system 33. The cooling medium of the condenser 32 is provided by the chiller 7.

[0032] The liquid outlet end of the second steam-water separator 31 and the liquid outlet end of the condenser 32 are communicated with the liquid seal device 34 through the fifth pipeline 35, and the liquid seal device 34 is communicated with the temperature control water tank 2; a pressure buffer tank 36 is arranged on the fifth pipeline 35. The separated water and the condensed water are recycled. Since there is still residual hydrogen in the separated water, a pressure buffer tank 36 is arranged in the fifth pipeline 35 to avoid adverse effects on the fifth pipeline 35 caused by excessive pressure. The liquid seal device 34 allows the water to flow into the temperature control water tank 2, and the residual hydrogen is discharged.

[0033] Embodiment 2 This embodiment provides a control method for the PEM electrolytic water hydrogen production system of Embodiment 1.

[0034] As Figure 2As shown, at startup, first, it is judged whether the value of the flow sensor 18 is greater than or equal to the idle flow rate. The idle flow rate refers to the minimum water flow threshold set to maintain the basic water circulation inside the electrolyzer 5 and avoid dry burning or local overheating during the startup phase or low-load operation of the PEM electrolytic water hydrogen production system. If this condition is met, the first solenoid valve 19 is closed, the second solenoid valve 20 is opened, and the valve opening of the three-way valve 9 is adjusted so that the liquid output from the circulation water tank 3 is 0; if this condition is not met, the water is continuously replenished through the circulation water tank 3 until the above condition is reached. At this time, water continuously circulates in the branch "the first steam-water separator 6 - three-way valve 9 - heat exchanger 4 - electrolyzer 5 - second solenoid valve 20 - first steam-water separator 6", and the electrolyzer 5 is started with a small current. As the electrolyzer 5 operates, the inlet temperature of the electrolyzer 5 (denoted as TE003) continuously rises, and the current value is gradually increased according to the inlet temperature value of the electrolyzer 5. At the same time, the rotation speed of the first water pump 10 is adjusted according to the current value until the rated current is reached. Specifically as follows: When T1 < TE003 ≤ T2, the current is loaded to 30% of the rated current; when T2 < TE003 ≤ T3, the current is loaded to 50% of the rated current; when T3 < TE003 ≤ T4, the current is loaded to 75% of the rated current; when T4 < TE003 ≤ the target inlet temperature of the electrolyzer 5, the current is loaded to the rated current.

[0035] According to the law of conservation of energy, a temperature model formula of the electrolyzer 5 is established, inputting the actual working current I of the power supply el and the measured single-cell voltage U cell , the outlet temperature T of the electrolyzer 5 out, PEM , the inlet temperature T of the electrolyzer 5 in, PEM to calculate the required value of the liquid flow rate flowing through the electrolyzer 5, and give a rotational speed signal to the first water pump 10 through the calculated required value of the liquid flow rate, so as to adjust the actual liquid flow rate in the pipeline.

[0036] The temperature model formula of the electrolyzer 5 is as follows: .

[0037] In the formula, U cell , the measured voltage of a single small cell of the electrolyzer 5, unit V; I el , the total DC current of the electrolyzer 5, unit A; n cell , the number of single small cells of the electrolyzer 5; V th , the theoretical voltage of a single small cell of the electrolyzer 5, unit V; T in, PEM , the inlet temperature of the electrolyzer 5, unit K; T out, PEM , the outlet temperature of the electrolyzer 5, unit K; T stack is the temperature of the electrolyzer 5, unit K; C stack , the specific heat capacity of the electrolyzer 5, unit K·kg -1 ·K-1 ; q cl , the liquid flow rate demand value, with the unit of kg·s -1 ; C cl , the specific heat capacity of the liquid, with the unit of K·kg -1 ·K -1 ; Q gas , the heat dissipation of the electrolytic cell 5 through air convection, and this value is determined by empirical data.

[0038] For the first water pump 10, establish a linear function relationship between the rotational speed and the flow rate. Based on the magnitude of the liquid flow rate demand value , obtain the actual rotational speed and the actual power through the flow rate - rotational speed - power diagram of the water pump. Give the actual rotational speed signal to the controller of the first water pump 10 to adjust the actual rotational speed of the first water pump 10 in real time, so as to meet the corresponding liquid flow rate demand values under different currents and meet the normal operation requirements of the electrolytic cell 5. The formula is as follows: .

[0039] In the formula, n w,0 , the rated rotational speed of the first water pump 10, with the unit of rpm; q w,0 , the rated flow rate of the first water pump 10, with the unit of L·min -1 ; n w,1 , the actual rotational speed of the first water pump 10, with the unit of rpm; q w,1 , the actual flow rate of the first water pump 10, with the unit of L·min -1 .

[0040] After the temperature at the inlet of the electrolytic cell 5 is greater than or equal to the target temperature at the inlet of the electrolytic cell 5, the temperature in the branch circulation has reached the target temperature at the inlet of the electrolytic cell 5, but the water in the circulation water tank 3 is still cold water. Since the temperature of the electrolytic cell 5 continues to increase during operation, therefore, open the first solenoid valve 19 and control the valve opening of the three-way valve 9 to gradually increase the liquid output of the circulation water tank 3 and gradually reduce the liquid output of the first steam - water separator 6. The cold water in the circulation water tank 3 is mixed with the hot water in the branch circulation and then flows into the electrolytic cell 5. By controlling the valve opening, the temperature at the inlet of the electrolytic cell 5 is kept constant. The outflow liquid of the electrolytic cell 5 can directly enter the circulation water tank 3, so that the temperature of the circulation water tank 3 continuously increases until the liquid output of the first steam - water separator 6 is 0, then close the second solenoid valve 20 to reach the stable operation stage.

[0041] When the PEM electrolytic water hydrogen production system is started, it also includes adjusting the temperature of the temperature control water tank 2 to reach the preset temperature value, and controlling the root mean square error (RMSE) value of the temperature in the temperature control water tank 2 to be less than the preset value. The RMSE value is collected at a frequency of 1 Hz, and the temperature of the temperature control water tank 2 is continuously collected for 5 s. During startup and stable operation, the liquid level of the circulation water tank 3 is continuously monitored. When the measured liquid level value is lower than the preset liquid level value, the temperature control water tank 2 is controlled to replenish water. The water replenishment strategy is as Figure 3 shown as follows: Judge whether the liquid level value LS001 of the temperature control water tank 2 meets the following conditions: the first preset value ≤ LS001 ≤ the second preset value; if not, when LS001 is less than the first preset value, open the third solenoid valve 21; when LS001 is greater than the second preset value, close the third solenoid valve 21. If it meets the conditions, then judge whether the liquid level value LS002 of the circulation water tank 3 meets the following conditions: the third preset value ≤ LS002 ≤ the fourth preset value; if not, when LS002 is less than the third preset value, open the fourth solenoid valve 22; when LS002 is greater than the fourth preset value, close the fourth solenoid valve 22. If it meets the conditions, then judge whether the RMSE value of the temperature control water tank 2 is greater than or equal to the preset value. If so, adjust the power of the heating module 23 of the temperature control water tank 2 until the RMSE value is less than the preset value. If not, turn off the heating module 23.

[0042] The calculation formula for the temperature RMSE value is as follows: .

[0043] In the formula, n is the number of samples, T 实测 represents the measured temperature value of the temperature control water tank 2, and T 目标 represents the target temperature value of the temperature control water tank 2.

[0044] The control method for the heat recovery process is as Figure 4 shown. When it is detected that the temperature value TE005 of the heat recovery system 8 < the inlet temperature TE003 of the electrolyzer 5, the refrigeration system is turned off, that is, the electric opening valve 37 is closed; the heat recovery system 8 is enabled, that is, the fifth solenoid valve 27 is opened, and the inlet temperature TE003 of the electrolyzer 5 is controlled in real time by adjusting the rotation speed of the second water pump 30 to make TE003 reach the target inlet temperature of the electrolyzer 5. When it is detected that the temperature value TE005 of the heat recovery system 8 ≥ the inlet temperature TE003 of the electrolyzer 5, the heat recovery system 8 is turned off, that is, the fifth solenoid valve 27 is closed; the refrigeration system is enabled, that is, the electric opening valve 37 is opened, and the inlet temperature TE003 of the electrolyzer 5 is adjusted by adjusting the cold water outlet temperature of the chiller 7 and the opening of the electric opening valve 37 to make TE003 reach the target inlet temperature of the electrolyzer 5. The above control method can complete the recovery and reuse of waste heat on the premise of stably controlling the inlet temperature of the electrolyzer 5.

[0045] The PEM electrolytic water hydrogen production system provided by the present invention has the functions of rapid start-up, automatic water replenishment and temperature control, and waste heat recovery, can achieve the best performance of the electrolytic cell 5, and extend the service life of the system.

[0046] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A PEM electrolytic water hydrogen production system, characterized in that, It includes a pure water machine, a temperature control water tank, a circulating water tank, a heat exchanger, an electrolyzer, a first steam-water separator and a control system; The pure water machine, the temperature control water tank, the circulating water tank, the heat exchanger and the electrolyzer are connected in series in sequence through pipelines; a three-way valve and a first water pump are arranged on the pipeline between the circulating water tank and the heat exchanger; The liquid outlet of the electrolyzer is communicated with the circulating water tank through a pipeline provided with a first solenoid valve, and the liquid outlet of the electrolyzer is communicated with the liquid inlet of the first steam-water separator through a pipeline provided with a second solenoid valve; the gas outlet of the first steam-water separator is communicated with the circulating water tank through a pipeline; The liquid outlet of the circulating water tank, the first water pump and the liquid outlet of the first steam-water separator are communicated with the three-way valve; The control system is used to control the opening and closing of the first solenoid valve and the second solenoid valve, the valve opening of the three-way valve, the rotation speed of the first water pump and the current of the electrolyzer.

2. The PEM electrolytic water hydrogen production system according to claim 1, wherein A third solenoid valve is arranged on the pipeline between the pure water machine and the temperature control water tank, and a fourth solenoid valve is arranged on the pipeline between the temperature control water tank and the circulating water tank; a heating module is arranged in the temperature control water tank, and the heating module is electrically connected with the control system.

3. The PEM electrolytic water hydrogen production system according to claim 1, characterized in that, It further includes a temperature acquisition unit, a liquid level acquisition unit and a flow rate acquisition unit. The temperature acquisition unit is used to acquire the temperature values of the temperature control water tank, the circulating water tank, the liquid inlet of the electrolyzer and the liquid outlet of the electrolyzer. The liquid level acquisition unit is used to acquire the liquid levels of the temperature control water tank and the circulating water tank. The flow rate acquisition unit is used to acquire the liquid inlet flow rate of the electrolyzer.

4. The PEM electrolytic water hydrogen production system according to claim 1, wherein It further includes a chiller, and the chiller is circularly communicated with the heat exchanger through a first pipeline and a second pipeline; an electric opening valve is arranged on the second pipeline.

5. The PEM electrolytic water hydrogen production system according to claim 4, characterized in that, It further includes a heat recovery system, and the heat recovery system is communicated with the first pipeline through a third pipeline. A third solenoid valve is arranged on the third pipeline; the heat recovery system is communicated with the second pipeline between the electric opening valve and the heat exchanger through a fourth pipeline; a second water pump is arranged on the fourth pipeline.

6. The PEM electrolytic water hydrogen production system according to claim 1, wherein, It further includes a second steam-water separator, a condenser and a hydrogen purification system; the second steam-water separator is communicated with the gas outlet of the electrolyzer, the gas outlet end of the second steam-water separator is communicated with the condenser, and the condenser is communicated with the hydrogen purification system.

7. The PEM electrolytic water hydrogen production system according to claim 6, wherein, The liquid outlet ends of the second steam-water separator and the condenser are communicated with a liquid seal device through a fifth pipeline, and the liquid seal device is communicated with the temperature control water tank; a pressure buffer tank is arranged on the fifth pipeline.

8. The PEM electrolytic water hydrogen production system according to claim 1, characterized in that, It further includes an oxygen treatment system, and the oxygen treatment system is communicated with the circulating water tank.

9. The control method of the PEM electrolytic water hydrogen production system according to any one of claims 1 to 8, characterized in that, It includes the following steps: When the PEM electrolytic water hydrogen production system is started, the water in the circulating water tank enters the electrolyzer through the three-way valve. When the water flow rate reaches the idle flow rate, close the first solenoid valve, open the second solenoid valve, and adjust the valve opening of the three-way valve to make the liquid output of the circulating water tank zero; gradually increase the current of the electrolyzer according to the measured value of the electrolyzer inlet temperature, and adjust the rotation speed of the first water pump according to the current value until the rated current is reached; After the electrolyzer inlet temperature is greater than or equal to the target temperature, open the first solenoid valve, and control the valve opening of the three-way valve to gradually increase the liquid output of the circulating water tank and gradually reduce the liquid output of the first steam-water separator. Control the electrolyzer inlet temperature to remain constant until the liquid output of the first steam-water separator is zero, and then close the second solenoid valve to reach the stable operation stage.

10. The control method according to claim 9, wherein, When starting the PEM electrolysis water hydrogen production system, it also includes adjusting the temperature of the temperature control water tank to reach the preset temperature value and controlling the root mean square error value of the temperature in the temperature control water tank to be less than the preset value; monitoring the liquid level of the circulation water tank, and when the measured liquid level value is lower than the preset liquid level value, controlling the temperature control water tank to replenish water.

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