Gas replacement control method of PEM hydrogen production system, medium and equipment

Abstract

The invention belongs to the technical field of hydrogen energy, and particularly relates to a gas replacement control method of a PEM hydrogen production system, a medium and equipment, and gas replacement comprises mixed replacement and pressurized replacement which are carried out in sequence; the control method comprises the following steps: calculating the total effective displacement volume in the PEM hydrogen production system; setting an allowable value range of the target hydrogen content after mixed replacement in the PEM hydrogen production system, and calculating the total replacement amount; fitting a relation curve within an allowable value range; calculating total replacement time; fitting a relation curve in an allowable value range of the target hydrogen content; and determining optimization according to limiting conditions. Compared with the prior art, the problems that in the prior art, gas replacement cannot be accurately controlled, and dead angle areas exist are solved. According to the scheme, on the premise of ensuring safety (uniform mixing), the replacement time is remarkably shortened, and waste of replacement gas is reduced.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen energy technology, specifically relating to a gas replacement control method, medium, and equipment for a PEM hydrogen production system. Background Technology

[0002] Proton exchange membrane (PEM) electrolysis of water to produce hydrogen has become one of the key technologies for renewable energy utilization and "green hydrogen" production due to its advantages such as fast response speed and high hydrogen purity. It is widely used in hydrogen refueling stations, power grid peak shaving and industrial fields, and is an important tool for achieving a clean energy transition.

[0003] However, the safe operation of a PEM hydrogen production system requires certain objective conditions: high-purity gas. Especially for the cathode where hydrogen is produced, a hydrogen concentration of 4%-75% in air reaches the explosion limit and is prone to explosion. Therefore, strict gas replacement is necessary to ensure the safe operation of the PEM hydrogen production system.

[0004] The primary and most critical purpose of gas replacement operation is to eliminate the possibility of an explosive environment formed by the mixing of hydrogen and oxygen (from air or within the system), ensuring a high level of safety during operation. It also guarantees the purity of the produced gas and the lifespan of the electrolyzer's core components. However, traditional replacement methods have the following problems: 1. Large consumption of replacement gas (usually nitrogen), resulting in high operating costs; 2. Long replacement time, leading to low system start-up efficiency; 3. Incomplete replacement in dead zones, posing safety hazards; 4. Lack of accurate dosage and time prediction models, relying on experience-based operation, which can easily lead to insufficient replacement time or excessive replacement gas.

[0005] Existing technologies, such as CN116876033B (disclosing a PEM electrolysis water-to-hydrogen system and its purge gas structure and control method), CN118086921A (disclosing a nitrogen replacement device and control method for a PEM electrolysis water-to-hydrogen system), and CN118910675A (disclosing an intermittent operation control method and system for an electrolysis water-to-hydrogen system), all provide considerable control over the replacement process of the PEM system. However, these existing technologies still cannot determine a precise range for the amount of replacement gas and the replacement time; they only provide relatively wide limits on the amount and number of times. Insufficient replacement time leading to incomplete replacement, and excessive replacement time resulting in significant waste of replacement gas, still exist. Furthermore, the existing gas replacement operation, which only uses a single-stage replacement method, is prone to creating dead zones in the system that cannot be completely replaced, leading to safety hazards.

[0006] Therefore, this invention proposes a novel gas displacement control method for a PEM hydrogen production system. Summary of the Invention

[0007] The purpose of this invention is to provide a gas replacement control method, medium, and equipment for a PEM hydrogen production system to solve at least one of the aforementioned problems. This addresses the issues in existing technologies where gas replacement is not precisely controlled, leading to wasted replacement gas, excessively long replacement time, and the existence of dead zones that hinder complete replacement. This solution employs a combined strategy of mixed replacement and pressurized replacement, along with reliable replacement time and nitrogen replacement quantity prediction, significantly shortening replacement time and reducing gas waste while ensuring safety (uniform mixing).

[0008] The objective of this invention is achieved through the following technical solution: The first aspect of this invention discloses a gas replacement control method for a PEM hydrogen production system, wherein the gas replacement includes sequentially performing a mixing replacement and a pressurized replacement; The control method includes the following steps: S1: Calculate the total effective displacement volume in the PEM hydrogen production system. ; S2: Set the target hydrogen content in the PEM hydrogen production system after mixing and replacement. The allowable range of values ​​is used to calculate the displacement gas pressure during pressurized displacement. ;based on and Calculate the displacement gas volume for mixed displacement and the replacement gas volume of pressurized replacement In order to obtain the total amount of replacement ;exist Fitting within the allowed range of values and Relationship curve; S3: Obtain the gas filling rate of the PEM hydrogen production system during the gas replacement process. and exhaust speed And calculate the displacement time of the mixed displacement. Replacement time with pressure replacement To obtain the total replacement time ; at the target hydrogen content Fitting within the allowed range of values and Relationship curve; S4: Based on the set maximum purging time and / or maximum purging rate Determine optimization based on constraints Based on deterministic optimization Implement gas replacement in the PEM hydrogen production system.

[0009] Preferably, in step S1, the total effective replacement volume The following steps were used to calculate the result: Obtain the fixed volume of the liquid-free fluid space in the PEM hydrogen production system. ; Obtain the total volume of the liquid phase fluid space in the PEM hydrogen production system. and liquid volume ,based on and Calculate gas phase volume ; based on and calculate .

[0010] Preferably, in step S2, the target hydrogen content The allowed value range is 0.1%-4%.

[0011] Preferably, in step S2, the displacement gas pressure It is obtained by calculation using the following formula: ; In the formula, To pressurize and replace the pressure after depressurization, The hydrogen content in the replacement gas. This represents the hydrogen content in the PEM hydrogen production system after gas replacement.

[0012] Preferably, in step S2, the displacement gas volume of the mixed displacement is... and the displacement gas volume of the pressurized replacement It is obtained by calculation using the following formula: ; ; In the formula, The hydrogen content in the replacement gas. The hydrogen content in the PEM hydrogen production system before gas replacement. Atmospheric pressure; The total amount of replacement It is obtained by calculation using the following formula: .

[0013] Preferably, in step S3, the displacement time of the mixed displacement is... and the replacement time of the aforementioned pressure replacement It is obtained by calculation using the following formula: ; ; In the formula, The density of the replacement gas; The total replacement time It is obtained by calculation using the following formula: .

[0014] Preferably, the PEM hydrogen production system includes at least a PEM electrolyzer and a separator; a pressure reducing valve is installed on the gas inlet pipe of the PEM electrolyzer; and a venting valve is installed on the exhaust pipe of the separator. In step S3, the inflation speed and exhaust speed The Cv values ​​were obtained by calibrating the pressure reducing valve and the venting valve, respectively.

[0015] Preferably, the PEM hydrogen production system includes at least a PEM electrolyzer and a separator; a pneumatic valve is also installed on the gas inlet pipe of the PEM electrolyzer; a pressure transmitter is installed on the connecting pipe between the PEM electrolyzer and the separator; and a vent valve is installed on the exhaust pipe of the separator. Step S4 is implemented through the following steps: S41: Deterministic Optimization Computational optimization and optimization ; S42: Open the venting valve and pneumatic valve to introduce replacement gas into the PEM electrolyzer until the optimal time is reached. ; S43: Close the vent valve and increase the pressure of the replacement gas to the optimal level. Then close the pneumatic valve; open the vent valve until the pressure measured by the pressure transmitter is less than atmospheric pressure, then close the vent valve.

[0016] A second aspect of the present invention discloses a computer-readable storage medium having a computer program stored thereon, wherein the computer program executes the control method described in any one of the above descriptions when it is run.

[0017] A third aspect of the present invention discloses a computer device, including a memory and a processor, wherein the memory stores a computer program that can run on the processor, and the processor executes the control method described in any one of the above descriptions when running the computer program.

[0018] The working principle of this invention is as follows: This invention establishes a dynamic calculation model of the effective volume of a PEM hydrogen production system and combines mixed displacement and pressurized displacement into a two-stage gas displacement control strategy. In the mixed displacement stage, nitrogen gas is constantly introduced to form a uniform dilution, rapidly reducing the hydrogen concentration within the system. In the pressurized displacement stage, the volume effect of gas compression and release is utilized to achieve secondary scavenging of residual gas. By acquiring signals in real time through sensors such as pressure transmitters and flow meters installed in the PEM hydrogen production system, the displacement curve can be calculated and the intermediate concentration dynamically determined. This strategy achieves optimal control of both gas volume and replacement time. It significantly reduces replacement gas consumption and shortens the replacement cycle while ensuring system safety.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The control method proposed in this invention has the following advantages: 1. Precision: Through dynamic volume (total replacement) This calculation ensures the accuracy and compatibility of subsequent calculations.

[0020] 2. High efficiency: This solution first ensures basic uniformity through mixing and replacement, and then further combines pressurized replacement to efficiently remove residual gas in the system, thereby achieving complete gas replacement in the PEM hydrogen production system, including dead zones.

[0021] 3. Transparency: This method can predict replacement time and improve pretreatment and operation and maintenance efficiency, reducing the proportion of useless costs (including time costs and replacement gas costs).

[0022] 4. Safety: A dual-insurance strategy (total replacement time + total replacement amount) ensures that the residual gas concentration in the final PEM hydrogen production system meets the standard. Attached Figure Description

[0023] Figure 1 A schematic diagram of the PEM hydrogen production system; Figure 2 This is a schematic diagram of the gas displacement control method; Figure 3 As in Example 2 - and - The relationship curve.

[0024] In the diagram: 1-PEM electrolytic cell; 2-system inlet pressure transmitter; 3-pressure reducing valve; 4-safety valve; 5-pneumatic valve; 6-check valve; 7-pressure transmitter; 8-liquid separator; 9-level gauge; 10-vent valve; 11-back pressure valve. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0026] Unless otherwise specified, the reagents used in the following description are conventional commercial products, the methods used are known in the art, and any other matters not covered herein can be handled using existing technology.

[0027] Example 1 A gas replacement control method for a PEM hydrogen production system, such as Figure 1 , 2 As shown, the gas replacement includes sequential mixing replacement and pressurized replacement; The control method includes the following steps: S1: Calculate the total effective displacement volume in the PEM hydrogen production system. ; S2: Set the target hydrogen content in the PEM hydrogen production system after mixing and replacement. The allowable range of values ​​is used to calculate the displacement gas pressure during pressurized displacement. ;based on and Calculate the displacement gas volume for mixed displacement and the replacement gas volume of pressurized replacement In order to obtain the total amount of replacement ;exist Fitting within the allowed range of values and Relationship curve; S3: Obtain the gas filling rate of the PEM hydrogen production system during the gas replacement process. and exhaust speed And calculate the displacement time of the mixed displacement. Replacement time with pressure replacement To obtain the total replacement time ; at the target hydrogen content Fitting within the allowed range of values and Relationship curve; S4: Based on the set maximum purging time and / or maximum purging rate Determine optimization based on constraints Based on deterministic optimization Implement gas replacement in the PEM hydrogen production system.

[0028] More specifically, in this embodiment: This gas replacement control method is based on, for example Figure 1The PEM hydrogen production system shown mainly includes a PEM electrolyzer, a separator tank, pipelines for fluid flow, and corresponding valves, sensors, etc. In addition, the PEM hydrogen production system may also include conventional equipment such as heat exchangers (not shown in the figure) to ensure the normal operation of the system. It should be noted that these unshown devices are included in the calculation of the control method of this scheme and do not affect the implementation and accuracy of the control method of this scheme.

[0029] Specifically, such as Figure 1 As shown, in this PEM hydrogen production system: The gas inlet pipe of PEM electrolysis cell 1 is sequentially equipped with a system inlet pressure transmitter 2, a pressure reducing valve 3, a pneumatic valve 5 and a check valve 6 along the gas flow direction. A branch line is also led out between the pressure reducing valve 3 and the pneumatic valve 5, and a safety valve 4 is installed on the branch line.

[0030] A pressure transmitter 7 is installed on the pipeline between PEM electrolyzer 1 and separator 8 (hydrogen-water separator).

[0031] A level gauge 9 is installed on the separator 8 to measure the liquid level inside the separator 8.

[0032] A vent valve 10 is installed on the exhaust pipe of the separator 8, and a branch line is also led out between the separator 8 and the vent valve 10, with a back pressure valve 11 installed on the branch line.

[0033] The implementation process of this gas replacement control method is as follows: Figure 2 As shown, nitrogen is used as the replacement gas, and the process involves sequential mixing and pressurized replacement, specifically including the following steps: S1, Received a gas replacement demand signal.

[0034] S2. Real-time calculation of the cavity volume of the PEM hydrogen production system (V_purge): Obtain the fixed volume of each pipe, heat exchanger, and other equipment without liquid phase flow. ; Obtain the total volume of containers affected by liquid level (such as separators). The liquid volume is calculated using level gauge readings and the container's geometric parameters. Subsequently, according to and Calculate gas phase volume : ; Calculate the total effective displacement volume in the current state. , And update the value to memory.

[0035] Setting: Target hydrogen content after mixing and replacement The allowed range of values ​​for (Cmid) (volume fraction), where a is... The lower limit of the value of is preferably 0.1%, and b is 0.1%. The lower limit of the value is preferably 4%; S3. Calculate the total number of replacements based on the range [a, b]. The curve of (V_N): 1) Mixing and replacement: Assuming that the original gas in the container is completely and ideally mixed with the added nitrogen, the composition of the gas in the container is the composition of the outlet gas; the hydrogen concentration in the PEM hydrogen production system is significantly reduced through mixing and replacement. Calculate the total amount of nitrogen required for the mixed displacement (displacement gas volume). : ; In the formula, The hydrogen content in the replacement gas, expressed as a percentage (volume fraction), typically 0%. The hydrogen content in the PEM hydrogen production system before gas replacement, expressed as a percentage (volume fraction), which can usually be calculated as 100%. 2) Pressurized replacement: Pressurize the PEM hydrogen production system to the target pressure (replacement gas pressure). (P_target), and then quickly depressurize, using the pressure difference and gas expansion effect to further remove the residual hydrogen; Calculate the nitrogen pressure required for pressurized replacement. : ; In the formula, The pressure after depressurization is measured in kPa. The hydrogen content in the PEM hydrogen production system after gas replacement is expressed as a percentage (volume fraction). Should The maximum value is the measured value of the system inlet pressure transmitter; Calculate the total amount of nitrogen required for pressurized replacement (replacement gas volume). : ; In the formula, (P0) is atmospheric pressure, which can be taken as 101.325 kPa; Then, the total amount of gas displacement. for: .

[0036] make ,by Let c be the step size (c is the number of calculations, preferably 10), and calculate... Within the range [a, b] Values, and obtained by fitting and The relationship curve.

[0037] S4. Calculate the total replacement time based on the [a, b] values. The curve of (t_N): First, the exhaust velocity of the PEM hydrogen production system was obtained by calibrating the Cv values ​​of the pressure reducing valve and the vent valve. and inflation speed ; Displacement time of mixed displacement (t1): ; Replacement time under pressure : ; In the formula, The density of nitrogen gas is typically taken as 8.508 kg / m³. 3 @20℃; Then, the total replacement time for: .

[0038] make ,by Given the step size, calculate Within the range [a, b] Values, and obtained by fitting and The relationship curve.

[0039] S5, according to and Relationship curve and and Determining and optimizing the relationship curve : right and Relationship curve and and The relationship curves were normalized, and the range in which the two curves were close to each other was selected as the initial selection. ; Further, the maximum purging time will be preset by the user. (t_MAX) or maximum purge rate (V_MAX) is used as a constraint for optimization. The range of values ​​it can take.

[0040] S6, in optimization The gas replacement is implemented within the range of values. value, and based on that The values ​​are used to calculate various parameters (mainly for optimization). and optimization ).

[0041] S7. Perform the mixed replacement process: Open the venting valve and turn on the pneumatic valve; S8. Determine whether the displacement time for the hybrid displacement has reached the optimal level. If the condition is met, proceed to S9; otherwise, continue with the mixed substitution. S9. After the mixing and replacement are completed, proceed with pressurized replacement: close the vent valve; S10. Determine if the pressure displacement pressure has reached the optimal level. If the target is reached, proceed to S11; otherwise, continue with pressurized replacement. S11. After pressurization and replacement are completed, close the pneumatic valve and open the vent valve; S12. Determine if the data measured by the pressure transmitter is less than... If it is less than, proceed to S13; if it is greater than, continue the release process. S13. After replacement is complete, close the product gas venting valve.

[0042] Example 2 In this embodiment, following the implementation scheme of Embodiment 1, the total effective replacement volume is first calculated in real time. =0.1m 3 ; =701.3 kPa; initial hydrogen concentration =100%, the hydrogen content of the replacement nitrogen gas. =0%, final target concentration =0.1%; Average mass flow rate during inflation =0.2 kg / min, average mass flow rate of effluent =0.5 kg / min, pressure relief =101.3 kPa, replacement time <10min ( ), Displacement purging dosage <1m 3 ( ).

[0043] Under these conditions, the optimal intermediate concentration can be selected through calculation. =0.57%, nitrogen usage during the mixed replacement stage Approximately 0.51m 3 ,time consuming Approximately 5.7 minutes; nitrogen volume during the pressurization and replacement phase Approximately 0.47m 3 ,time consuming Approximately 1.5 minutes; Total nitrogen replacement volume Approximately 0.98m 3 Total time Approximately 7.2 minutes. Through the combined effects of mixing and pressurization, the final residual hydrogen concentration is approximately 0.1%, achieving the set target.

[0044] like Figure 3 As shown in the figure, the intermediate concentration is displayed. Total replacement and total replacement time The relationship curve. As can be seen from the graph, with... The increase in the total amount of replacement The replacement time is on an upward trend. It shows a downward trend, when When it is approximately 0.57%, and The fact that the two curves are close to each other and reach the total nitrogen purging setpoint indicates that the amount of replacement gas and the time corresponding to this point are close to the optimal range.

[0045] This invention utilizes this characteristic, by... An optimization point was set around 0.57%, achieving an optimal balance between replacement gas consumption and replacement time. Under the premise of ensuring safety (uniform mixing, residual hydrogen concentration ≤0.1%), the total replacement time was controlled within 7.2 minutes, and the total gas consumption was approximately 0.98 m³. 3 .

[0046] Comparative Example 1 This comparative example only uses the same initial conditions as Example 2, involving pressurization and replacement treatment. Calculations show that: pressurizing the PEM hydrogen production system from 101.3 kPa to 701.3 kPa, then depressurizing it back to 101.3 kPa, and repeating this depressurization process five times, is required to reduce the hydrogen concentration to 0.1%, corresponding to a nitrogen replacement volume of approximately 5.4 m³. 3 The replacement time is approximately 3 minutes, which does not meet the limit requirement for the total amount of nitrogen used for replacement.

[0047] Example 3 In this embodiment, following the implementation scheme of Embodiment 1, the total effective replacement volume is first calculated in real time. =1.0m 3 ; =601.3 kPa; initial hydrogen concentration =100%, the hydrogen content of the replacement nitrogen gas. =0%, final target concentration =0.1%; Average mass flow rate during inflation =0.135kg / s, average mass flow rate of effluent =0.135kg / s, pressure relief =101.3 kPa, replacement time <5min ( ), Displacement purging dosage <5m 3 ( ).

[0048] Under these conditions, the optimal intermediate concentration can be selected through calculation. =0.61%, nitrogen usage during the mixed replacement stage Approximately 2.49m 3 ,time consuming Approximately 152 seconds; nitrogen volume during the pressurization and replacement phase Approximately 2.5m 3 ,time consuming Approximately 35 seconds; Total nitrogen consumption for replacement Approximately 4.99m 3 Total time Approximately 4.5 minutes. Through the combined effects of mixing and pressurization, the final residual hydrogen concentration is approximately 0.1%, achieving the set target.

[0049] In summary, this solution achieves: 1. accurate dynamic measurement of cavity volume; 2. through a combination of mixed replacement and pressurized replacement strategies, significantly shortening replacement time and reducing replacement gas consumption while ensuring safety (uniform mixing); thus providing reliable prediction of replacement time and nitrogen replacement volume, improving operational transparency and planning.

[0050] On the other hand, the present invention also provides a computer storage medium storing executable program code; the executable program code is used to execute any of the above-described control methods.

[0051] On the other hand, the present invention also provides a terminal device, including a memory and a processor; the memory stores program code that can be executed by the processor; the program code is used to execute any of the above-described control methods.

[0052] For example, the program code can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the program code in the terminal device.

[0053] The terminal device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that the terminal device may also include input / output devices, network access devices, buses, etc.

[0054] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0055] The memory can be an internal storage unit of the terminal device, such as a hard drive or RAM. The memory can also be an external storage device of the terminal device, such as a plug-in hard drive, SmartMedia Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory can include both internal and external storage units of the terminal device. The memory is used to store the program code and other programs and data required by the terminal device. The memory can also be used to temporarily store data that has been output or will be output.

[0056] The aforementioned computer storage medium and terminal equipment are created based on the aforementioned weld positioning method or automatic weld welding method. Their technical functions and beneficial effects will not be elaborated here. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A gas replacement control method for a PEM hydrogen production system, characterized in that, The gas replacement includes sequential mixed replacement and pressurized replacement; The control method includes the following steps: S1: Calculate the total effective displacement volume in the PEM hydrogen production system. ; S2: Set the target hydrogen content in the PEM hydrogen production system after mixing and replacement. The allowable range of values ​​is used to calculate the displacement gas pressure during pressurized displacement. ;based on and Calculate the displacement gas volume for mixed displacement and the replacement gas volume of pressurized replacement In order to obtain the total amount of replacement ;exist Fitting within the allowed range of values and Relationship curve; S3: Obtain the gas filling rate of the PEM hydrogen production system during the gas replacement process. and exhaust speed And calculate the displacement time of the mixed displacement. Replacement time with pressure replacement To obtain the total replacement time ; at the target hydrogen content Fitting within the allowed range of values and Relationship curve; S4: Based on the set maximum purging time and / or maximum purging rate Determine optimization based on constraints Based on deterministic optimization Implement gas replacement in the PEM hydrogen production system.

2. The gas replacement control method for a PEM hydrogen production system according to claim 1, characterized in that, In step S1, the total effective replacement volume The following steps were used to calculate the result: Obtain the fixed volume of the liquid-free fluid space in the PEM hydrogen production system. ; Obtain the total volume of the liquid phase fluid space in the PEM hydrogen production system. and liquid volume ,based on and Calculate gas phase volume ; based on and calculate .

3. The gas replacement control method for a PEM hydrogen production system according to claim 1, characterized in that, In step S2, the target hydrogen content The allowed value range is 0.1%-4%.

4. The gas replacement control method for a PEM hydrogen production system according to claim 1, characterized in that, In step S2, the displacement gas pressure It is obtained by calculation using the following formula: ； In the formula, To pressurize and replace the pressure after depressurization, The hydrogen content in the replacement gas. This represents the hydrogen content in the PEM hydrogen production system after gas replacement.

5. The gas replacement control method for a PEM hydrogen production system according to claim 1, characterized in that, In step S2, the displacement gas volume of the mixed displacement and the displacement gas volume of the pressurized replacement It is obtained by calculation using the following formula: ； ； In the formula, The hydrogen content in the replacement gas. The hydrogen content in the PEM hydrogen production system before gas replacement. Atmospheric pressure; The total amount of replacement It is obtained by calculation using the following formula: 。 6. The gas replacement control method for a PEM hydrogen production system according to claim 1, characterized in that, In step S3, the displacement time of the mixed displacement and the replacement time of the aforementioned pressure replacement It is obtained by calculation using the following formula: ； ； In the formula, The density of the replacement gas; The total replacement time It is obtained by calculation using the following formula: 。 7. The gas replacement control method for a PEM hydrogen production system according to claim 1, characterized in that, The PEM hydrogen production system includes at least a PEM electrolyzer (1) and a separator (8); a pressure reducing valve (3) is installed on the gas inlet pipe of the PEM electrolyzer (1); and a venting valve (10) is installed on the exhaust pipe of the separator (8). In step S3, the inflation speed and exhaust speed The values ​​of Cv are obtained by calibrating the pressure reducing valve (3) and the venting valve (10) respectively.

8. The gas replacement control method for a PEM hydrogen production system according to claim 1, characterized in that, The PEM hydrogen production system includes at least a PEM electrolyzer (1) and a separator (8); a pneumatic valve (5) is also installed on the gas inlet pipe of the PEM electrolyzer (1); a pressure transmitter (7) is installed on the connecting pipe between the PEM electrolyzer (1) and the separator (8); and a vent valve (10) is installed on the exhaust pipe of the separator (8). Step S4 is implemented through the following steps: S41: Deterministic Optimization Computational optimization and optimization ; S42: Open the venting valve (10) and the pneumatic valve (5) to introduce replacement gas into the PEM electrolyzer (1) until the time is optimized. ; S43: Close the vent valve (10) and increase the pressure of the replacement gas to the optimal level. Then close the pneumatic valve (5); open the vent valve (10) until the pressure measured by the pressure transmitter (7) is less than the atmospheric pressure, and then close the vent valve (10).

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program executes the control method according to any one of claims 1 to 8 when it runs.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program executable on the processor, characterized in that, When the processor runs the computer program, it executes the control method according to any one of claims 1 to 8.

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