A control method, apparatus, and system for producing hydrogen through water electrolysis.

Abstract

This invention discloses a control method, apparatus, and system for a water electrolysis hydrogen production system, relating to the field of water electrolysis hydrogen production technology. The method includes: when a first adsorption tower is detected to be in a purification state, determining the current adsorption capacity of the first adsorption tower based on a molecular sieve adsorption capacity decay model; determining the predicted adsorption time of the first adsorption tower based on its current adsorption capacity and a dynamic time adjustment model; and when both the first and second adsorption towers meet the state switching conditions based on the absolute value of the pressure difference downstream of the first and second adsorption towers and the predicted adsorption time, or based on the absolute value of the pressure difference downstream of the first and second adsorption towers and the dew point of the product gas, controlling the adsorption tower state switching module to switch the first adsorption tower to a regeneration state and the second adsorption tower to a purification state. This invention can effectively reduce the operating cost of the adsorption towers in a water electrolysis hydrogen production system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen production by water electrolysis, and in particular to a control method and device for a hydrogen production system by water electrolysis and the hydrogen production system by water electrolysis. BACKGROUND

[0002] The hydrogen production system by water electrolysis has the following problems in operation: the switching logic of the two adsorption towers of the traditional hydrogen production equipment is controlled by fixed time, which is simple and convenient, but cannot dynamically adjust the switching time according to the actual saturation state of the adsorbent, which may lead to early switching when the adsorbent is not saturated or switching after over-saturation, reducing the service life of the adsorbent and increasing the maintenance cost. In the PSA process of the system, the conventional long sweep after desorption wastes hydrogen. The molecular sieve used for purification in the traditional hydrogen production system cannot accurately determine the replacement cycle, which may cause unpredictability of system shutdown maintenance and affect the continuous operation efficiency.

[0003] How to reduce the operation cost of the adsorption tower in the hydrogen production system by water electrolysis is a technical problem that needs to be solved by those skilled in the art. SUMMARY

[0004] The present application provides a control method and device for a hydrogen production system by water electrolysis and the hydrogen production system by water electrolysis, which can effectively reduce the operation cost of the adsorption tower in the hydrogen production system by water electrolysis.

[0005] In a first aspect, the present application provides a control method for a hydrogen production system by water electrolysis, wherein the hydrogen production system by water electrolysis comprises a hydrogen production module, a first adsorption tower, a second adsorption tower, an adsorption tower state switching module, a pressure monitoring module and a dew point monitoring module.

[0006] The hydrogen production module is connected to the first adsorption tower and the second adsorption tower, the adsorption tower state switching module comprises a first electromagnetic valve and a second electromagnetic valve arranged on the channel connecting the hydrogen production module to the first adsorption tower and the second adsorption tower, respectively; the pressure monitoring module comprises a first pressure sensor and a second pressure sensor arranged downstream of the first adsorption tower and the second adsorption tower, respectively; and the dew point monitoring module is connected to the channel through which the product gas is discharged downstream of the first adsorption tower and the second adsorption tower.

[0007] The control method for the hydrogen production system by water electrolysis comprises the following steps:

[0008] When it is detected that the first adsorption tower is currently in a purification state, the current adsorption capacity of the first adsorption tower is determined according to a molecular sieve adsorption capacity decay model.

[0009] determining a predicted adsorption time of the first adsorption tower according to the current adsorption capacity of the first adsorption tower and a dynamic time adjustment model;

[0010] when it is determined that both the first adsorption tower and the second adsorption tower meet the state switching condition according to the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower and the predicted adsorption time, or according to the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower and the dew point of the product gas, the adsorption tower state switching module is controlled to switch the first adsorption tower to a regeneration state and switch the second adsorption tower to a purification state.

[0011] Optionally, the molecular sieve adsorption capacity decay model is:

[0012] wherein, is the current adsorption capacity, is the initial adsorption capacity; k is the decay coefficient, and N is the cumulative adsorption and regeneration cycle number.

[0013] Optionally, the dynamic time adjustment model is: ; wherein, is the predicted adsorption time, is the initial design adsorption time.

[0014] Optionally, when it is determined that both the first adsorption tower and the second adsorption tower meet the state switching condition according to the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower and the predicted adsorption time, or according to the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower and the dew point of the product gas, the adsorption tower state switching module is controlled to switch the first adsorption tower to a regeneration state and switch the second adsorption tower to a purification state, which includes:

[0015] when it is detected that the purification time of the first adsorption tower is equal to the predicted adsorption time, and the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower is less than or equal to a preset pressure difference, or the dew point of the product gas is greater than a preset dew point, and the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower is less than or equal to a preset pressure difference, it is determined that both the first adsorption tower and the second adsorption tower meet the state switching condition;

[0016] the first electromagnetic valve is controlled to be closed, and the second electromagnetic valve is controlled to be opened.

[0017] Optionally, after determining the predicted adsorption time of the first adsorption tower according to the current adsorption capacity of the first adsorption tower and the dynamic time adjustment model, the method further includes:

[0018] ​determining that the molecular sieve of the first adsorption tower needs to be replaced when it is detected that the ratio of the current adsorption capacity to the initial adsorption capacity is less than a preset ratio;

[0019] triggering a warning to prompt that the molecular sieve of the first adsorption tower needs to be replaced.

[0020] Optionally, the adsorption tower state switching module further comprises a third electromagnetic valve and a fourth electromagnetic valve; the downstream of the first adsorption tower and the second adsorption tower further comprises a purge channel, and a normally open needle valve is arranged in the purge channel; the dew point monitoring module is further connected with a channel through which purge gas is discharged upstream of the first adsorption tower and the second adsorption tower;

[0021] The third electromagnetic valve is arranged on a channel connected with the dew point monitoring module upstream of the first adsorption tower; and the fourth electromagnetic valve is arranged on a channel connected with the dew point monitoring module upstream of the second adsorption tower.

[0022] After the first electromagnetic valve is controlled to be closed and the second electromagnetic valve is controlled to be opened, the method further comprises:

[0023] controlling the third electromagnetic valve to be opened, and the purge gas downstream of the second adsorption tower purges the first adsorption tower through the purge channel;

[0024] controlling the third electromagnetic valve to be closed when it is detected that the dew point of the purge gas is less than or equal to the preset dew point and the pressure drop change rate between the upstream and the downstream of the first adsorption tower is less than or equal to a preset change rate.

[0025] Optionally, the pressure monitoring module further comprises a third pressure sensor; and the third pressure sensor is arranged upstream of the first adsorption tower and the second adsorption tower.

[0026] After the third electromagnetic valve is controlled to be opened and the purge gas downstream of the second adsorption tower purges the first adsorption tower through the purge channel, the method further comprises:

[0027] determining that the molecular sieve of the first adsorption tower needs to be replaced when it is detected that the pressure drop change rate between the upstream and the downstream of the first adsorption tower is greater than the preset change rate.

[0028] triggering a warning to prompt that the molecular sieve of the first adsorption tower needs to be replaced.

[0029] In a second aspect, an embodiment of the present application further provides a control device of a water electrolysis hydrogen production system, comprising: an adsorption capacity determination module, configured to determine a current adsorption capacity of a first adsorption tower according to a molecular sieve adsorption capacity attenuation model when it is detected that the first adsorption tower is currently in a purification state;

[0030] a predicted adsorption time determination module configured to determine a predicted adsorption time of the first adsorption tower according to a current adsorption capacity of the first adsorption tower and a dynamic time adjustment model;

[0031] a state switching module configured to control the adsorption tower state switching module to switch the first adsorption tower to a regeneration state and switch the second adsorption tower to a purification state when it is determined that both the first adsorption tower and the second adsorption tower meet state switching conditions according to an absolute value of a pressure difference downstream of the first adsorption tower and the second adsorption tower and the predicted adsorption time, or according to an absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower and a dew point of product gas.

[0032] In a third aspect, the embodiments of the present application also provide an electrolytic water hydrogen production system, characterized in that it comprises: the control device, the hydrogen production module, the first adsorption tower, the second adsorption tower, the adsorption tower state switching module, the pressure monitoring module, and the dew point monitoring module of the electrolytic water hydrogen production system provided in the above embodiments.

[0033] The hydrogen production module is connected to the first adsorption tower and the second adsorption tower, the adsorption tower state switching module comprises a first electromagnetic valve and a second electromagnetic valve arranged on passages connecting the hydrogen production module to the first adsorption tower and the second adsorption tower, respectively; the pressure monitoring module comprises a first pressure sensor and a second pressure sensor arranged downstream of the first adsorption tower and the second adsorption tower, respectively; and the dew point monitoring module is connected to a passage through which product gas is discharged downstream of the first adsorption tower and the second adsorption tower.

[0034] Optionally, the adsorption tower state switching module further comprises a third electromagnetic valve and a fourth electromagnetic valve; downstream of the first adsorption tower and the second adsorption tower, there is further provided a purge passage in which a normally open needle valve is arranged; and the dew point monitoring module is further connected to a passage through which purge gas is discharged upstream of the first adsorption tower and the second adsorption tower.

[0035] The third electromagnetic valve is arranged on a passage connecting the upstream of the first adsorption tower to the dew point monitoring module; and the fourth electromagnetic valve is arranged on a passage connecting the upstream of the second adsorption tower to the dew point monitoring module.

[0036] The pressure monitoring module further comprises a third pressure sensor; and the third pressure sensor is arranged upstream of the first adsorption tower and the second adsorption tower.

[0037] The technical scheme of the embodiment of the present application takes the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower and the predicted adsorption time or the dew point of the product gas which can be dynamically adjusted as the judgment condition for switching the state of the adsorption tower, optimizes the control method of the adsorption tower purification and regeneration in the prior art, introduces the molecular sieve adsorption capacity attenuation model in the purification control method, can accurately predict the current adsorption capacity of the adsorbent in the adsorption tower, and according to the dynamic adjustment time model, the predicted adsorption time can be accurately calculated according to the actual saturation state of the adsorbent. The reduction of the service life of the adsorbent caused by the premature switching or the switching after excessive saturation is avoided, and the operation cost of the adsorption tower in the electrolytic water hydrogen production system can be effectively reduced.

[0038] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0040] Figure 1 is a structural schematic diagram of an electrolytic water hydrogen production system provided by the embodiment of the present application;

[0041] Figure 2 is a flow chart of a control method of an electrolytic water hydrogen production system provided by the embodiment of the present application;

[0042] Figure 3 is a flow chart of another control method of an electrolytic water hydrogen production system provided by the embodiment of the present application;

[0043] Figure 4 is a structural schematic diagram of a control device of an electrolytic water hydrogen production system provided by the embodiment of the present application;

[0044] Figure 5 is a structural schematic diagram of another control device of an electrolytic water hydrogen production system provided by the embodiment of the present application. DETAILED DESCRIPTION

[0045] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort should belong to the scope of protection of the present application.

[0046] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0047] Figure 1 is a structural schematic diagram of a water electrolysis hydrogen production system provided by an embodiment of the present application, Figure 2 is a flowchart of a control method of a water electrolysis hydrogen production system provided by an embodiment of the present application. The embodiment can be applicable to the case of controlling a water electrolysis hydrogen production system. The method can be executed by a control device of the water electrolysis hydrogen production system. The control device of the water electrolysis hydrogen production system can be realized in the form of hardware and / or software. The control device of the water electrolysis hydrogen production system can be configured in the water electrolysis hydrogen production system.

[0048] Reference Figure 1 The water electrolysis hydrogen production system comprises a hydrogen production module 1, a first adsorption tower A, a second adsorption tower B, an adsorption tower state switching module 2, a pressure monitoring module 3 and a dew point monitoring module 4. The hydrogen production module 1 is connected with the first adsorption tower A and the second adsorption tower B. The adsorption tower state switching module 2 comprises a first electromagnetic valve 21 and a second electromagnetic valve 22 arranged on passages connecting the hydrogen production module 1 with the first adsorption tower A and the second adsorption tower B, respectively. The pressure monitoring module 3 comprises a first pressure sensor 31 and a second pressure sensor 32 arranged downstream of the first adsorption tower A and the second adsorption tower B, respectively. The dew point monitoring module 4 is connected with passages discharging product gas downstream of the first adsorption tower A and the second adsorption tower B.

[0049] It should be noted that in the pressure swing adsorption (PSA) dual-tower system, the "purification state" and the "regeneration state" refer to different functional states performed by the two adsorption towers at different time periods, with the purpose of realizing the separation of gas and the recycling of adsorbent through pressure changes. In the purification state, one tower (such as the first adsorption tower A) is in the working (adsorption) mode, used to adsorb impurities from the raw gas and output high-purity product gas. The main process of the purification state is that the raw gas enters the working adsorption tower at a certain pressure, and the adsorbent (such as molecular sieve, activated carbon, etc.) in the adsorption tower selectively adsorbs impurity gas. The non-adsorbed or weakly adsorbed components are output as product gas, achieving the purpose of purification.

[0050] The regeneration state is when the adsorbent of one tower (such as the first adsorption tower A) approaches saturation, the system switches to the other tower (such as the second adsorption tower B) for purification, while the first adsorption tower A is regenerated (desorption / regeneration) to remove the adsorbed impurities and restore its adsorption capacity. The main process of the regeneration state is to first lower the pressure of the first adsorption tower A (usually discharged to the atmosphere or low pressure side), so that the adsorbed impurities are partially desorbed due to the pressure drop. Then use a part of the already purified gas (such as product gas from the second adsorption tower B) as a purge gas to blow back into the first adsorption tower A at a lower pressure, further blowing out the impurities in the adsorbent pores to achieve deep regeneration. After regeneration, the first adsorption tower A is re-pressurized to prepare for the next adsorption cycle.

[0051] Reference Figure 2 The control method of the electrolytic water hydrogen production system comprises:

[0052] S210, when it is detected that the first adsorption tower is currently in the purification state, determining the current adsorption capacity of the first adsorption tower according to the molecular sieve adsorption capacity decay model.

[0053] It can be understood that the current purification state of the first adsorption tower can be determined by detecting the state of the first electromagnetic valve and the second electromagnetic valve arranged on the channel connecting the hydrogen production module and the first adsorption tower and the second adsorption tower. When it is detected that the first electromagnetic valve is open and the second electromagnetic valve is closed, it can be determined that the first adsorption tower is currently in the purification state. After the system is started, data is collected in real time, and the change value of the adsorption capacity is calculated in real time according to the molecular sieve adsorption capacity decay model to predict the current adsorption capacity.

[0054] S220, determining the predicted adsorption time of the first adsorption tower according to the current adsorption capacity of the first adsorption tower and the dynamic time adjustment model.

[0055] Understandably, the current adsorption capacity of the first adsorption tower can be substituted into the dynamic time adjustment model to determine the predicted adsorption time of the first adsorption tower.

[0056] S230. When it is determined that both the first and second adsorption towers meet the state switching conditions based on the absolute value of the pressure difference downstream of the first and second adsorption towers and the predicted adsorption time, or based on the absolute value of the pressure difference downstream of the first and second adsorption towers and the dew point of the product gas, the adsorption tower state switching module is controlled to switch the first adsorption tower to the regeneration state and the second adsorption tower to the purification state.

[0057] This invention optimizes existing methods for controlling the purification and regeneration of adsorption towers by using the absolute value of the pressure difference downstream of the first and second adsorption towers, along with dynamically adjustable predicted adsorption time or the dew point of the product gas, as criteria for switching the state of the adsorption towers. Regarding purification control, a molecular sieve adsorption capacity decay model is introduced, which can accurately predict the current adsorption capacity of the adsorbent in the adsorption tower. Furthermore, based on a dynamically adjusted time model, the predicted adsorption time can be accurately calculated according to the actual saturation state of the adsorbent. This avoids premature switching before the adsorbent is fully saturated or switching after over-saturation, which reduces the adsorbent's lifespan and effectively lowers the operating costs of the adsorption towers in water electrolysis hydrogen production systems.

[0058] Optionally, based on the above embodiments, the molecular sieve adsorption capacity decay model is as follows: ;in, This represents the current adsorption capacity. denoted as the initial adsorption capacity; k is the decay coefficient; and N is the cumulative number of regeneration cycles after adsorption.

[0059] Here, k is a calibration value that is related to factors such as the temperature and pressure of the adsorption tower.

[0060] Optionally, based on the above embodiments, the dynamic time adjustment model is as follows: ;in, To predict adsorption time, This is the initial design adsorption time.

[0061] Understandably, the current adsorption capacity and the initial designed adsorption time obtained from the molecular sieve adsorption capacity decay model can be substituted into the dynamic time adjustment model to obtain the predicted adsorption time.

[0062] Figure 3 This is a flowchart of another control method for a water electrolysis hydrogen production system provided in an embodiment of the present invention, see reference. Figure 3 The method includes the following steps:

[0063] S310. When it is detected that the first adsorption tower is currently in a purification state, the current adsorption capacity of the first adsorption tower is determined according to the molecular sieve adsorption capacity decay model.

[0064] S320. Based on the current adsorption capacity of the first adsorption tower and the dynamic time adjustment model, determine the predicted adsorption time of the first adsorption tower.

[0065] S331. When it is detected that the purification time of the first adsorption tower is equal to the predicted adsorption time, and the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower is less than or equal to the preset pressure difference, or the dew point of the product gas is greater than the preset dew point, and the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower is less than or equal to the preset pressure difference, it is determined that both the first adsorption tower and the second adsorption tower meet the state switching conditions.

[0066] The preset pressure difference can be 0~0.3Mpa, and the preset dew point can be -62~-76℃.

[0067] S332, Control the first solenoid valve to close and the second solenoid valve to open.

[0068] Understandably, after the first solenoid valve is closed and the second solenoid valve is opened, the second adsorption tower can be purified. At this time, the state of the second adsorption tower switches from the regeneration state to the purification state.

[0069] Optionally, step S230 in the above embodiment may include steps S331 and S332.

[0070] Optionally, based on the above embodiments, after step S320, the method further includes:

[0071] S341. When the ratio of the current adsorption capacity to the initial adsorption capacity is detected to be less than the preset ratio, it is determined that the molecular sieve of the first adsorption tower needs to be replaced.

[0072] For example, the initial adsorption capacity can be 25 hours, and the preset ratio can be 60-70%, which can be set according to the requirements of the molecular sieve manufacturer.

[0073] S342, triggering an early warning, indicating that the molecular sieve of the first adsorption tower needs to be replaced.

[0074] It should be noted that after the molecular sieve in the first adsorption tower is indicated as needing replacement, the system can be shut down for replacement at a suitable time. Alternatively, a redundant backup adsorption tower can be set up, and the system can be switched to the backup molecular tower without shutting down the system. The backup molecular tower has upstream and downstream connections for [missing information - likely related to equipment or features]. Figure 1 The first and second adsorption towers in the process use the same solenoid valves and pressure sensors.

[0075] This invention predicts whether the molecular sieve of the adsorption tower needs to be replaced based on the ratio of the current adsorption capacity to the initial adsorption capacity. This allows for accurate positioning of the replacement cycle, preventing sudden system shutdowns from affecting continuous operation efficiency and further reducing the operating cost of the adsorption tower in the water electrolysis hydrogen production system.

[0076] Optionally, based on the above embodiments, continue to refer to... Figure 1 The adsorption tower state switching module 2 also includes a third solenoid valve 23 and a fourth solenoid valve 24; downstream of the first adsorption tower A and the second adsorption tower B, there is also a purge channel 5, in which a normally open needle valve 51 is provided; the third solenoid valve 23 is located on the channel upstream of the first adsorption tower A that connects to the dew point monitoring module 4; the fourth solenoid valve 24 is located on the channel upstream of the second adsorption tower B that connects to the dew point monitoring module 4. The dew point monitoring module 4 is also connected to the channel upstream of the first adsorption tower A and the second adsorption tower B that discharges purge gas.

[0077] Continue to refer to Figure 3 After step S332, the following is also included:

[0078] S333: Control the third solenoid valve to open, and the purging gas downstream of the second adsorption tower purges the first adsorption tower through the purging channel.

[0079] Understandably, the third solenoid valve 23 and the fourth solenoid valve 24 are in the closed state by default. After controlling the first solenoid valve to close and the second solenoid valve to open, purification operation can be performed on the second adsorption tower. At this time, the state of the second adsorption tower switches from regeneration state to purification state. Controlling the third solenoid valve to open can reduce the pressure of the first adsorption tower to atmospheric pressure for pressure swing desorption regeneration. Then, a portion of the gas discharged downstream of the second adsorption tower will enter the purge channel to purge the first adsorption tower.

[0080] S334. When the dew point of the purge gas is detected to be less than or equal to the preset dew point and the pressure drop change rate between the upstream and downstream of the first adsorption tower is less than or equal to the preset change rate, the third solenoid valve is controlled to close.

[0081] The preset dew point can be -62 to -76℃, and the preset change rate can be 0-0.03 MPa / min. When the dew point of the purge gas is detected to be less than or equal to the preset dew point and the pressure drop change rate between the upstream and downstream of the first adsorption tower is less than or equal to the preset change rate, the third solenoid valve is closed, which can increase the pressure of the first adsorption tower to the same level as the second adsorption tower, and wait for the next switching cycle.

[0082] Understandably, in terms of regeneration control methods, the purging time needs to be dynamically adjusted as the adsorbent's degree of pulverization increases throughout its lifespan. This invention embodiment uses a dual approach, based on the dew point of the purging gas and the rate of pressure drop change between the upstream and downstream of the adsorption tower, to dynamically adjust the purging time. This ensures the reliability of the decompression and purging strategies for the adsorption tower, guarantees stable system operation, and further reduces the operating cost of the adsorption tower in the water electrolysis hydrogen production system.

[0083] It should be noted that after the second adsorption tower switches to the purification state, the control method of the water electrolysis hydrogen production system provided in this embodiment of the invention can also be used to control the tower state switching. For example, when the second adsorption tower is detected to be in the purification state, the current adsorption capacity of the second adsorption tower is determined according to the molecular sieve adsorption capacity decay model. The predicted adsorption time of the second adsorption tower is determined based on the current adsorption capacity and the dynamic time adjustment model. When it is determined that both the first and second adsorption towers meet the state switching conditions based on the absolute value of the pressure difference downstream of the first and second adsorption towers and the predicted adsorption time, or based on the absolute value of the pressure difference downstream of the first and second adsorption towers and the dew point of the product gas, the adsorption tower state switching module controls the second adsorption tower to switch to the regeneration state and the first adsorption tower to the purification state.

[0084] Optionally, based on the above embodiments, continue to refer to... Figure 1 The pressure monitoring module 3 also includes a third pressure sensor 33; the third pressure sensor 33 is located upstream of the first adsorption tower A and the second adsorption tower B. (Continue to refer to...) Figure 3 After step S333, the following is also included:

[0085] S351. When the pressure drop change rate between the upstream and downstream of the first adsorption tower is detected to be greater than the preset change rate, it is determined that the molecular sieve of the first adsorption tower needs to be replaced.

[0086] S352, triggering an early warning, indicating that the molecular sieve of the first adsorption tower needs to be replaced.

[0087] It should be noted that after the molecular sieve in the first adsorption tower is indicated as needing replacement, the system can be shut down for replacement at a suitable time. Alternatively, a redundant backup adsorption tower can be set up, and the system can be switched to the backup molecular tower without shutting down the system. The backup molecular tower has upstream and downstream connections for [missing information - likely related to equipment or features]. Figure 1 The first and second adsorption towers use the same solenoid valves and pressure sensors.

[0088] This invention predicts whether the molecular sieve of the adsorption tower needs to be replaced based on the pressure drop change rate between the upstream and downstream of the first adsorption tower. This allows for accurate positioning of the replacement cycle, avoiding sudden system shutdowns that could affect continuous operation efficiency and further reducing the operating cost of the adsorption tower in the water electrolysis hydrogen production system.

[0089] In summary, this invention optimizes the existing control methods for purification and regeneration of adsorption towers by using the absolute value of the pressure difference downstream of the first and second adsorption towers, along with dynamically adjustable predicted adsorption time or the dew point of the product gas, as the criteria for switching the state of the adsorption towers. Regarding purification control, a molecular sieve adsorption capacity decay model is introduced, which can accurately predict the current adsorption capacity of the adsorbent in the adsorption tower. Furthermore, based on a dynamically adjusted time model, the predicted adsorption time can be accurately calculated according to the actual saturation state of the adsorbent. This avoids premature switching before the adsorbent is fully saturated or switching after oversaturation, thus reducing the adsorbent lifespan and effectively lowering the operating cost of the adsorption towers in the water electrolysis hydrogen production system. In addition, predicting whether the molecular sieve in the adsorption tower needs replacement based on the ratio of the current adsorption capacity to the initial adsorption capacity allows for accurate positioning of the replacement cycle, preventing sudden system shutdowns from affecting continuous operation efficiency and further reducing the operating cost of the adsorption towers in the water electrolysis hydrogen production system. The system utilizes a dual approach, combining the dew point of the purge gas with the pressure drop rate between the upstream and downstream of the adsorption tower, to dynamically adjust the purge time. This ensures the reliability of the depressurization and purge strategies for the adsorption tower, guaranteeing stable system operation and further reducing the operating costs of the adsorption tower in the water electrolysis hydrogen production system. Predicting the need for molecular sieve replacement based on the ratio of current adsorption capacity to initial adsorption capacity allows for accurate positioning of the replacement cycle, preventing sudden system shutdowns from impacting continuous operation efficiency and further reducing the operating costs of the adsorption tower in the water electrolysis hydrogen production system. Similarly, predicting the need for molecular sieve replacement based on the pressure drop rate between the upstream and downstream of the first adsorption tower allows for accurate positioning of the replacement cycle, preventing sudden system shutdowns from impacting continuous operation efficiency and further reducing the operating costs of the adsorption tower in the water electrolysis hydrogen production system.

[0090] Figure 4 This is a schematic diagram of the control device for a water electrolysis hydrogen production system provided in an embodiment of the present invention. (Refer to...) Figure 4 The device includes: an adsorption capacity determination module 410, an adsorption time determination module 420, and a state switching module 430.

[0091] The adsorption capacity determination module 410 is used to determine the current adsorption capacity of the first adsorption tower according to the molecular sieve adsorption capacity decay model when it is detected that the first adsorption tower is currently in the purification state. The predicted adsorption time determination module 420 is used to determine the predicted adsorption time of the first adsorption tower according to the current adsorption capacity of the first adsorption tower and the dynamic time adjustment model. The state switching module 430 is used to control the adsorption tower state switching module to switch the first adsorption tower to the regeneration state and the second adsorption tower to the purification state when it is determined that the first adsorption tower and the second adsorption tower both meet the state switching conditions based on the absolute value of the pressure difference downstream of the first adsorption tower and the predicted adsorption time, or based on the absolute value of the pressure difference downstream of the first adsorption tower and the dew point of the product gas.

[0092] Figure 5 This is a schematic diagram of the control device for another water electrolysis hydrogen production system provided in an embodiment of the present invention. Optionally, based on the above embodiments, refer to... Figure 5 The device also includes a molecular sieve status determination module 510 and an early warning module 520. The molecular sieve status determination module 510 is used to determine that the molecular sieve of the first adsorption tower needs to be replaced when the ratio of the current adsorption capacity to the initial adsorption capacity is less than a preset ratio. The early warning module 520 is used to trigger an early warning to indicate that the molecular sieve of the first adsorption tower needs to be replaced.

[0093] Optionally, based on the above embodiments, the molecular sieve state determination module 510 is further configured to determine that the molecular sieve of the first adsorption tower needs to be replaced when the pressure drop change rate between the upstream and downstream of the first adsorption tower is detected to be greater than the preset change rate.

[0094] The control device for the water electrolysis hydrogen production system provided in this embodiment of the invention can execute the control method for the water electrolysis hydrogen production system provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the execution method. For contents not described in detail in the embodiments of the invention, please refer to the control method for the water electrolysis hydrogen production system provided in the above embodiments.

[0095] This invention also provides an electrolytic water hydrogen production system, comprising: a control device for the electrolytic water hydrogen production system provided in the above embodiments, a hydrogen production module 1, a first adsorption tower A, a second adsorption tower B, an adsorption tower state switching module 2, a pressure monitoring module 3, and a dew point monitoring module 4; the hydrogen production module 1 is connected to both the first adsorption tower A and the second adsorption tower B; the adsorption tower state switching module 2 includes a first solenoid valve 21 and a second solenoid valve 22 respectively disposed on the channels connecting the hydrogen production module 1 to the first adsorption tower A and the second adsorption tower B; the pressure monitoring module 3 includes a first pressure sensor 31 and a second pressure sensor 32 respectively disposed downstream of the first adsorption tower A and the second adsorption tower B; and the dew point monitoring module 4 is connected to the downstream channels for discharging product gas from the first adsorption tower A and the second adsorption tower B.

[0096] Optionally, based on the above embodiments, continue to refer to... Figure 1 The adsorption tower state switching module also includes a third solenoid valve 23 and a fourth solenoid valve 24; downstream of the first adsorption tower A and the second adsorption tower B, there is also a purge channel 5, in which a normally open needle valve 51 is provided; the third solenoid valve 23 is located on the channel upstream of the first adsorption tower A that connects to the dew point monitoring module 4; the fourth solenoid valve 24 is located on the channel upstream of the second adsorption tower B that connects to the dew point monitoring module 4. The dew point monitoring module 4 is also connected to the channel upstream of the first adsorption tower A and the second adsorption tower B that discharges purge gas. The pressure monitoring module 3 also includes a third pressure sensor 33; the third pressure sensor 33 is located upstream of the first adsorption tower A and the second adsorption tower B.

[0097] Optionally, based on the above embodiments, continue to refer to... Figure 1 The hydrogen production module 1 includes an electrolyzer 11, a power supply 12, a pure water system 13, a cooling system 14, a gas-water separator 15, and a purification device 16. The power supply 12, pure water system 13, and cooling system 14 are all connected to the input terminal of the electrolyzer 11. The channel connecting the electrolyzer 11 and the two adsorption towers A and B also includes the gas-water separator 15 and the purification device 16. The adsorption tower state switching module 2 also includes a fifth solenoid valve 25, a sixth solenoid valve 26, and a seventh solenoid valve 27. The seventh solenoid valve 27 and the fifth solenoid valve 25 are sequentially located downstream of the two adsorption towers A and B and between them and the dew point monitoring module 4. The sixth solenoid valve 26 is located upstream of the two adsorption towers A and B and between it and the dew point monitoring module 4.

[0098] It should be noted that when the electrolysis hydrogen production system is controlled using the control method of the electrolysis hydrogen production system provided in the embodiments of the present invention, the fifth solenoid valve 25, the sixth solenoid valve 26 and the seventh solenoid valve 27 are all in the open state.

[0099] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0100] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A control method of a hydrogen production system by electrolysis of water, characterized by, The electrolytic water hydrogen production system comprises a hydrogen production module, a first adsorption tower, a second adsorption tower, an adsorption tower state switching module, a pressure monitoring module, and a dew point monitoring module. The hydrogen production module is connected with the first adsorption tower and the second adsorption tower, the adsorption tower state switching module comprises a first electromagnetic valve and a second electromagnetic valve arranged on passages connecting the hydrogen production module with the first adsorption tower and the second adsorption tower respectively, the pressure monitoring module comprises a first pressure sensor and a second pressure sensor arranged downstream of the first adsorption tower and the second adsorption tower respectively, and the dew point monitoring module is connected with a passage through which product gas is discharged downstream of the first adsorption tower and the second adsorption tower. The control method of the electrolytic water hydrogen production system comprises: When it is detected that the first adsorption tower is currently in a purification state, determining a current adsorption capacity of the first adsorption tower according to a molecular sieve adsorption capacity decay model; Determining a predicted adsorption time of the first adsorption tower according to the current adsorption capacity of the first adsorption tower and a dynamic time adjustment model; When it is determined that the first adsorption tower and the second adsorption tower both meet state switching conditions according to an absolute value of a pressure difference downstream of the first adsorption tower and the second adsorption tower and the predicted adsorption time, or according to the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower and a dew point of the product gas, controlling the adsorption tower state switching module to switch the first adsorption tower to a regeneration state and switch the second adsorption tower to a purification state.

2. The control method of the water electrolysis hydrogen production system according to claim 1, characterized by, The molecular sieve adsorption capacity attenuation model is: ; wherein, is the current adsorption capacity, is the initial adsorption capacity; k is the decay coefficient, and N is the cumulative number of cycles of adsorption followed by regeneration.

3. The control method of the water electrolysis hydrogen production system according to claim 2, characterized by, The dynamic time adjustment model is: ; wherein, is a predicted adsorption time, is an initial design adsorption time.

4. The control method of the electrolytic water hydrogen production system according to claim 3, wherein When it is determined that the first adsorption tower and the second adsorption tower both meet state switching conditions according to an absolute value of a pressure difference downstream of the first adsorption tower and the second adsorption tower and the predicted adsorption time, or according to the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower and a dew point of the product gas, controlling the adsorption tower state switching module to switch the first adsorption tower to a regeneration state and switch the second adsorption tower to a purification state comprises: When it is detected that a purification time of the first adsorption tower is equal to the predicted adsorption time, and the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower is less than or equal to a preset pressure difference, or the dew point of the product gas is greater than a preset dew point, and the absolute value of the pressure difference downstream of the first adsorption tower and the second adsorption tower is less than or equal to the preset pressure difference, it is determined that the first adsorption tower and the second adsorption tower both meet state switching conditions; Controlling the first electromagnetic valve to be closed and the second electromagnetic valve to be opened.

5. The control method of the water electrolysis hydrogen production system according to claim 1, characterized by, After determining the predicted adsorption time of the first adsorption tower according to the current adsorption capacity of the first adsorption tower and the dynamic time adjustment model, the method further comprises: When it is detected that a ratio of the current adsorption capacity to an initial adsorption capacity is less than a preset ratio, it is determined that the molecular sieve of the first adsorption tower needs to be replaced; Triggering a warning to prompt that the molecular sieve of the first adsorption tower needs to be replaced.

6. The control method of the water electrolysis hydrogen production system according to claim 4, characterized by, The adsorption tower state switching module further comprises a third electromagnetic valve and a fourth electromagnetic valve; downstream of the first adsorption tower and the second adsorption tower further comprises a purge channel, and a normally open needle valve is arranged in the purge channel; the dew point monitoring module is further connected with a channel through which purge gas is discharged upstream of the first adsorption tower and the second adsorption tower; The third electromagnetic valve is arranged on a channel connected with the dew point monitoring module upstream of the first adsorption tower; the fourth electromagnetic valve is arranged on a channel connected with the dew point monitoring module upstream of the second adsorption tower; After the first electromagnetic valve is controlled to be closed and the second electromagnetic valve is controlled to be opened, the method further comprises: The third electromagnetic valve is controlled to be opened, and the purge gas downstream of the second adsorption tower is controlled to pass through the purge channel to purge the first adsorption tower; When it is detected that the dew point of the purge gas is less than or equal to the preset dew point and the pressure drop change rate between the upstream and the downstream of the first adsorption tower is less than or equal to the preset change rate, the third electromagnetic valve is controlled to be closed.

7. The control method of the water electrolysis hydrogen production system according to claim 6, characterized by, The pressure monitoring module further comprises a third pressure sensor; the third pressure sensor is arranged upstream of the first adsorption tower and the second adsorption tower; After the third electromagnetic valve is controlled to be opened and the purge gas downstream of the second adsorption tower is controlled to pass through the purge channel to purge the first adsorption tower, the method further comprises: When it is detected that the pressure drop change rate between the upstream and the downstream of the first adsorption tower is greater than the preset change rate, it is determined that the molecular sieve of the first adsorption tower needs to be replaced; An early warning is triggered to prompt that the molecular sieve of the first adsorption tower needs to be replaced.

8. A control device of a hydrogen production system by electrolysis of water, characterized by, The control method for the electrolytic water hydrogen production system of any one of claims 1-7, the control device of the electrolytic water hydrogen production system comprising: an adsorption capacity determination module configured to determine a current adsorption capacity of a first adsorption tower according to a molecular sieve adsorption capacity decay model when it is detected that the first adsorption tower is currently in a purification state; a predicted adsorption time determination module configured to determine a predicted adsorption time of the first adsorption tower according to the current adsorption capacity of the first adsorption tower and a dynamic time adjustment model; a state switching module configured to control an adsorption tower state switching module to switch the first adsorption tower to a regeneration state and switch a second adsorption tower to a purification state when it is determined that both the first adsorption tower and the second adsorption tower meet state switching conditions according to an absolute value of a pressure difference downstream of the first adsorption tower and the second adsorption tower and the predicted adsorption time, or according to an absolute value of a pressure difference downstream of the first adsorption tower and the second adsorption tower and a dew point of product gas.

9. A hydrogen production system by electrolysis of water, characterized by, comprising: the control device of the electrolytic water hydrogen production system of claim 8, a hydrogen production module, a first adsorption tower, a second adsorption tower, an adsorption tower state switching module, a pressure monitoring module, and a dew point monitoring module; The hydrogen production module is connected with the first adsorption tower and the second adsorption tower, the adsorption tower state switching module comprises a first electromagnetic valve and a second electromagnetic valve arranged on passages respectively connecting the hydrogen production module with the first adsorption tower and the second adsorption tower; the pressure monitoring module comprises a first pressure sensor and a second pressure sensor arranged downstream of the first adsorption tower and the second adsorption tower respectively; and the dew point monitoring module is connected with a passage through which product gas is discharged downstream of the first adsorption tower and the second adsorption tower.

10. The water electrolysis hydrogen production system according to claim 9, characterized in that, The adsorption tower state switching module further comprises a third electromagnetic valve and a fourth electromagnetic valve; downstream of the first adsorption tower and the second adsorption tower further comprises a purge passage, and a normally open needle valve is arranged in the purge passage; and the dew point monitoring module is further connected with a passage through which purge gas is discharged upstream of the first adsorption tower and the second adsorption tower; The third electromagnetic valve is arranged on a passage connecting upstream of the first adsorption tower with the dew point monitoring module; and the fourth electromagnetic valve is arranged on a passage connecting upstream of the second adsorption tower with the dew point monitoring module; The pressure monitoring module further comprises a third pressure sensor; and the third pressure sensor is arranged upstream of the first adsorption tower and the second adsorption tower.

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