Width-adjustable alkaline electrolytic bath, hydrogen production system and control method

Abstract

The invention relates to the technical field of water electrolysis hydrogen production, and provides a width-adjustable alkaline electrolytic bath, a hydrogen production system and a control method. The electrolytic cell body comprises a plurality of small electrolytic chambers, an oxygen side flow channel is arranged in the electrolytic cell body, and the anode sides of the small electrolytic chambers are all connected with the oxygen side flow channel; and a dilution gas flow channel is further arranged in the electrolytic bath body, an outlet of the dilution gas flow channel is connected with the oxygen side flow channel, an inlet of the dilution gas flow channel is suitable for being connected with a dilution gas source, and the dilution gas source is suitable for providing non-combustible dilution gas. Through the arrangement, the problem of production safety of the electrolytic cell can be fundamentally solved, and the electrolytic cell can produce safely and stably in a full-load range, so that the electrolytic cell can more fully adapt to wide fluctuation of output of renewable energy sources, and the effective utilization rate of power generation of the renewable energy sources is greatly improved; meanwhile, the problems of short service life, poor reliability and the like caused by frequent starting and stopping of the electrolytic cell are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production by electrolyzing water, and particularly to an alkaline electrolyzer with wide-range adjustment, a hydrogen production system and a control method. Background Art

[0002] With the improvement of global environmental awareness and the progress of renewable energy technologies, clean energies such as wind energy and solar energy are gradually becoming the core of energy transformation. However, the characteristics of these renewable energies determine that their outputs are random and volatile, which poses challenges to the stable operation of the power grid. To address this issue, hydrogen energy storage has emerged as an innovative power storage solution and has attracted much attention due to its environmental friendliness, high conversion efficiency and flexible application.

[0003] The diaphragm is one of the key components of the electrolysis chamber of an alkaline electrolyzer. It has two basic functions: First, it allows the free movement of ions in the electrolyzer circuit; second, it isolates hydrogen and oxygen generated during the electrocatalysis process. At the same time, the diaphragm also needs to have certain chemical and physical stabilities to meet the requirements during assembly and operation. Currently, composite diaphragms based on polyphenylene sulfide (PPS) are widely used in alkaline electrolyzers, which are essentially porous diaphragms. Under the dynamic operating conditions of the electrolyzer, the pressures on both sides of the diaphragm are inconsistent and are easily imbalanced, leading to the interpenetration of hydrogen and oxygen on both sides of the diaphragm. In particular, hydrogen molecules with small molecular weights and extremely fast moving speeds are prone to penetrate the diaphragm and diffuse from the cathode side to the anode oxygen side, resulting in the hydrogen content (hydrogen in oxygen) in the oxygen at the outlet of the oxygen separator exceeding the standard, thus triggering system alarms and interlock shutdowns.

[0004] When the production load of the electrolyzer decreases, the diffusion amount of hydrogen diffusing from the cathode to the anode remains basically unchanged, while the oxygen production at the anode decreases. Therefore, the hydrogen in oxygen at the outlet of the oxygen separator increases. As the production load decreases, the hydrogen in oxygen increases. When the production load decreases to a certain lower limit, the hydrogen content (hydrogen in oxygen) in the oxygen at the outlet of the oxygen separator will exceed the safety limit (the lower explosion limit of hydrogen is 4%), bringing the risk of "electrolyzer explosion".

[0005] Therefore, the production load of an alkaline electrolyzer is usually within a certain range. Currently, the mainstream production load of electrolyzers is 50 - 110%, and some new electrolyzers can be extended to 30 - 110% through technical optimization. Among them, the lower limit of the production load (50% or 30%) is determined by the upper limit of the hydrogen in oxygen at the outlet of the oxygen separator, and a certain safety margin is considered (when the hydrogen in oxygen ≥ 1.5%, the system alarms; when ≥ 1.8%, the system interlocks and stops).

[0006] In order to broaden the production load range of the electrolytic hydrogen production system, in the relevant technology, pure oxygen is sometimes mixed into the oxygen separator, so that the initial oxygen at the outlet of the electrolyzer that originally exceeds the standard (hydrogen in oxygen > 1.8%) is mixed with high-purity oxygen in the oxygen separator to achieve a hydrogen content of <1.5% at the outlet of the oxygen separator, thereby reducing the production load.

[0007] However, in actual applications, it was found that when the production load of the electrolyzer continued to decrease to a certain lower limit, due to the mixing of pure oxygen, although the hydrogen content in the mixed oxygen at the outlet of the oxygen separator can be guaranteed to still meet the standard (hydrogen content <1.5%), the hydrogen content of the initial oxygen at the outlet of the electrolyzer has long exceeded the lower explosion limit of hydrogen (the lower explosion limit of hydrogen is 4%), posing a huge safety hazard.

[0008] Therefore, how to further expand the production load range of the electrolytic hydrogen production system while avoiding safety hazards so that it can fully adapt to the wide and rapid fluctuations in renewable energy output is an important issue that needs to be solved urgently. Summary of the invention

[0009] The present invention provides an alkaline electrolyzer with wide adjustment range, a hydrogen production system and a control method, which are used to solve the defect in the prior art that the production load is difficult to further reduce due to the limitation of the lower explosion limit of hydrogen. While effectively avoiding safety hazards, safe and stable production within the full load range can be achieved.

[0010] A wide-range adjustable alkaline electrolytic cell provided according to the present invention comprises: an electrolytic cell body; The electrolytic cell body includes a plurality of electrolytic chambers, an oxygen side flow channel is arranged in the electrolytic cell body, and the anode sides of the plurality of electrolytic chambers are connected to the oxygen side flow channel; A dilution gas flow channel is also provided in the electrolytic cell body, the outlet of the dilution gas flow channel is connected to the oxygen side flow channel, and the inlet is suitable for connecting to a dilution gas source, and the dilution gas source is suitable for providing non-flammable dilution gas.

[0011] According to a wide-range adjustable alkaline electrolytic cell provided by the present invention, a plurality of electrolytic chambers are stacked and arranged along the length direction of the electrolytic cell body, and each of the electrolytic chambers includes a plate, an anode electrode, a diaphragm, a cathode electrode and a plate crimped in sequence along the length direction of the electrolytic cell body.

[0012] According to the wide-width adjustable alkaline electrolytic cell provided by the present invention, the electrode plates located at both ends of the electrolytic cell body are end electrode plates, and the electrode plate located between the two end electrode plates is an intermediate electrode plate; the oxygen side flow channel is arranged along the length direction of the electrolytic cell body and one end thereof penetrates through one of the end electrode plates to form an oxygen side outlet; The inlet of the dilution gas flow channel is arranged on the other end plate, and the outlet extends along the length direction of the electrolytic cell body and is communicated with the other end of the oxygen-side flow channel relative to the oxygen-side outlet.

[0013] According to an alkaline electrolytic cell with wide-range adjustment provided by the present invention, a check structure is arranged between the anode side of the electrolytic chamber and the oxygen-side flow channel, and the check structure is used for enabling unidirectional conduction from the anode side to the oxygen-side flow channel.

[0014] According to an alkaline electrolytic cell with wide-range adjustment provided by the present invention, a check valve is connected to the inlet of the dilution gas flow channel.

[0015] According to an alkaline electrolytic cell with wide-range adjustment provided by the present invention, a hydrogen-side flow channel is further arranged in the electrolytic cell body, and the cathode sides of multiple electrolytic chambers are all connected to the hydrogen-side flow channel.

[0016] According to an alkaline electrolytic cell with wide-range adjustment provided by the present invention, the hydrogen-side flow channel is arranged along the length direction of the electrolytic cell body, and one end penetrates through one of the end plates to form a hydrogen-side outlet.

[0017] According to an alkaline electrolytic cell with wide-range adjustment provided by the present invention, an alkali liquid flow channel is further arranged in the electrolytic cell body, and the cathode sides and anode sides of multiple electrolytic chambers are all connected to the alkali liquid flow channel.

[0018] According to an alkaline electrolytic cell with wide-range adjustment provided by the present invention, the alkali liquid flow channel is arranged along the length direction of the electrolytic cell body, and one end penetrates through one of the end plates to form an alkali liquid inlet.

[0019] The present invention further provides a hydrogen production system, which includes a dilution gas source and at least one alkaline electrolytic cell with wide-range adjustment as described in any one of the above; the dilution gas source is connected to the inlet of the dilution gas flow channel.

[0020] According to a hydrogen production system provided by the present invention, the dilution gas source includes a dilution gas supply module, a dilution gas compressor and a dilution gas buffer tank which are connected in sequence; The outlet of the dilution gas buffer tank is connected to the inlet of the dilution gas flow channel.

[0021] According to a hydrogen production system provided by the present invention, it further includes: an oxygen separator, the inlet of which is connected to the oxygen-side outlet of the electrolytic cell body; an oxygen purification system, the inlet of which is connected to the outlet of the oxygen separator, and the outlet of which is connected to the dilution gas storage tank, and is configured to be the dilution gas supply module.

[0022] According to a hydrogen production system provided by the present invention, a first pressure transmitter is provided on the dilution gas buffer tank, and a second pressure transmitter is provided on the oxygen separator; And / or, a hydrogen content detector is connected to the outlet of the oxygen separator.

[0023] The present invention also provides a control method for an electrolytic hydrogen production system, including the following steps: Obtain the hydrogen content in the initial oxygen generated by the electrolytic cell body; When it is determined that the hydrogen content in the initial oxygen does not meet the set conditions, control the dilution gas source to introduce dilution gas into the dilution gas flow channel so that the hydrogen content in the mixed gas meets the set conditions; When it is determined that the hydrogen content in the initial oxygen meets the set conditions, control the dilution gas source to stop introducing dilution gas into the dilution gas flow channel; Preferably, controlling the dilution gas source to introduce dilution gas into the dilution gas flow channel includes: Obtain the fluid pressure in the oxygen-side flow channel; Based on the fluid pressure, adjust the dilution gas pressure in the dilution gas buffer tank so that the pressure difference between the dilution gas pressure and the fluid pressure remains at a set threshold; Preferably, controlling the dilution gas source to introduce dilution gas into the dilution gas flow channel further includes: When it is determined that the hydrogen content in the initial oxygen increases, increase the flow rate at the outlet of the dilution gas source; When it is determined that the hydrogen content in the initial oxygen decreases, decrease the flow rate at the outlet of the dilution gas source.

[0024] The wide-range adjustable alkaline electrolytic cell, hydrogen production system and control method provided by the present invention, in the process of electrolytic water to produce hydrogen, initial oxygen is generated on the anode side of the electrolytic cell compartment. The mixture of the initial oxygen and the alkaline solution is discharged from the anode side of the electrolytic cell compartment and flows into the oxygen-side flow channel. The initial oxygen and the alkaline solution discharged from the anode sides of multiple electrolytic cell compartments are collected by the oxygen-side flow channel and then discharged from the electrolytic cell body. When the hydrogen content in the initial oxygen in the oxygen-side flow channel exceeds the standard due to a decrease in production load, load fluctuation or other reasons, the inlet of the dilution gas flow channel can be connected to the dilution gas source. The non-combustible dilution gas enters the oxygen-side flow channel through the dilution gas flow channel and mixes with the initial oxygen in the oxygen-side flow channel, thereby reducing the hydrogen content in the initial oxygen in the oxygen-side flow channel, making the hydrogen content in the initial oxygen in the oxygen-side flow channel always meet the preset standard and not be limited by the production load. Fundamentally solve the problem of the production safety of the electrolytic cell. The electrolytic cell can operate safely and stably within the full load range, enabling it to more fully adapt to the wide-range fluctuations of renewable energy output, greatly improving the effective utilization rate of renewable energy power generation, and at the same time avoiding problems such as low life and poor reliability caused by frequent start-stop of the electrolytic cell. Description of the Drawings

[0025] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a schematic structural diagram of a wide-width adjustable alkaline electrolyzer provided by an embodiment of the present invention.

[0027] Figure 2 It is a schematic structural diagram of a hydrogen production system provided by an embodiment of the present invention.

[0028] Figure 3 It is a schematic structural diagram of a hydrogen production system provided by another embodiment of the present invention.

[0029] Figure 4 It is a schematic structural diagram of a hydrogen production system provided by another embodiment of the present invention.

[0030] Figure 5 It is a schematic structural diagram of a hydrogen production system provided by another embodiment of the present invention.

[0031] Reference numerals: 10. Electrolyzer body; 11. Electrolysis cell; 110. Plate; 111. Anode electrode; 112. Diaphragm; 113. Cathode electrode; 12. Oxygen-side flow channel; 120. Oxygen-side outlet; 13. Dilution gas flow channel; 130. Check valve; 14. Hydrogen-side flow channel; 140. Hydrogen-side outlet; 15. Alkali solution flow channel; 150. Alkali solution inlet; 16. Gasket; 20. Dilution gas source; 21. Dilution gas compressor; 22. Dilution gas buffer tank; 220. First pressure transmitter; 221. Drainage pipeline; 23. Dilution gas storage tank; 230. Pure oxygen pipeline; 24. Dilution gas branch pipe; 30. Oxygen separator; 300. Hydrogen content detector; 301. Second pressure transmitter; 31. Oxygen purification system; 40. Hydrogen separator; 41. Hydrogen purification system; 50. Alkali solution cooler; 60. Circulation pump; 70. Flow transmitter; 80. Flow regulating valve. Detailed implementation manners

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts fall within the scope of protection of the present invention.

[0033] In order to better understand the wide-range adjustable alkaline electrolyzer, hydrogen production system and control method provided in the embodiments of the present invention, their application background is first introduced. Hydrogen energy storage, as a new type of renewable electricity storage technology, has attracted much attention due to its advantages such as environmental friendliness, high conversion efficiency and flexible application.

[0034] The diaphragm is a key component of the electrolytic chamber in the alkaline electrolyzer. It allows the free movement of ions in the circuit of the electrolyzer, while isolating the hydrogen and oxygen produced during the electrocatalytic process. Alkaline electrolyzers widely use composite diaphragms based on polyphenylene sulfide. This membrane can easily lead to hydrogen and oxygen crosstalk on both sides of the diaphragm under the dynamic operation conditions of the electrolyzer. In particular, hydrogen molecules with small molecular weight and extremely fast movement speed can easily penetrate the diaphragm and diffuse from the cathode side to the anode oxygen side, causing the hydrogen content (hydrogen in oxygen) in the oxygen at the outlet of the oxygen separator to exceed the standard, thereby triggering system alarms and interlock shutdowns. Therefore, the production load of alkaline electrolyzers is usually in a range. The current mainstream electrolyzer production load is 50~110%. Some new electrolyzers can be expanded to 30~110% through technical optimization. In order to broaden the production load range of the electrolytic hydrogen production system, in the relevant technology, pure oxygen is sometimes mixed into the oxygen separator, so that the initial oxygen at the outlet of the electrolyzer that originally exceeds the standard (hydrogen in oxygen > 1.8%) is mixed with high-purity oxygen in the oxygen separator to achieve a hydrogen content of <1.5% at the outlet of the oxygen separator, thereby reducing the production load.

[0035] However, in actual applications, it was found that when the production load of the electrolyzer continued to decrease to a certain lower limit, due to the mixing of pure oxygen, although the hydrogen content in the mixed oxygen at the outlet of the oxygen separator can be guaranteed to still meet the standard (hydrogen content <1.5%), the hydrogen content of the initial oxygen at the outlet of the electrolyzer has long exceeded the lower explosion limit of hydrogen (the lower explosion limit of hydrogen is 4%), posing a huge safety hazard.

[0036] Therefore, the electrolyzer and hydrogen production system under the above configuration will still have a certain lower limit of production load. When the production load is lower than the lower limit, the electrolyzer still needs to be shut down, resulting in the abandonment of wind and solar power. What is more serious is that frequent start and stop have a significant negative impact on the durability and reliability of the alkaline electrolyzer.

[0037] Therefore, how to further expand the production load range of the electrolytic hydrogen production system while avoiding safety hazards so that it can fully adapt to the wide and rapid fluctuations in renewable energy output is an important issue that needs to be solved urgently.

[0038] Based on the above problems and findings, the embodiments of the present invention provide a wide-range adjustable alkaline electrolyzer, a hydrogen production system and a control method, which can effectively avoid potential safety hazards while achieving safe and stable production within the full load range, thus fully adapting to the wide-range fluctuations of renewable energy output, significantly improving the effective utilization rate of renewable energy power generation, and at the same time avoiding problems such as low lifespan and poor reliability caused by frequent start-stop of the electrolyzer.

[0039] The following will describe Figures 1-5 the wide-range adjustable alkaline electrolyzer, the hydrogen production system and the control method of the present invention.

[0040] Referring to Figure 1 , a wide-range adjustable alkaline electrolyzer includes an electrolyzer body 10; the electrolyzer body 10 includes a plurality of electrolysis compartments 11, an oxygen-side flow channel 12 is arranged in the electrolyzer body 10, and the anode sides of the plurality of electrolysis compartments 11 are all connected to the oxygen-side flow channel 12; a dilution gas flow channel 13 is further arranged in the electrolyzer body 10, the outlet of the dilution gas flow channel 13 is connected to the oxygen-side flow channel 12, and the inlet is suitable for connecting to a dilution gas source 20, and the dilution gas source 20 is suitable for providing a non-combustible dilution gas.

[0041] During the process of hydrogen production by electrolyzing water, primary oxygen is generated on the anode side of the electrolysis compartment 11, and the mixture of primary oxygen and alkali solution is discharged from the anode side of the electrolysis compartment 11 and flows into the oxygen-side flow channel 12, and the primary oxygen and alkali solution discharged from the anode sides of the plurality of electrolysis compartments 11 are converged through the oxygen-side flow channel 12 and then discharged from the electrolyzer body 10.

[0042] When the hydrogen content in the primary oxygen in the oxygen-side flow channel 12 exceeds the standard due to a decrease in production load, load fluctuation or other reasons, the inlet of the dilution gas flow channel 13 can be connected to the dilution gas source 20, and the non-combustible dilution gas enters the oxygen-side flow channel 12 through the dilution gas flow channel 13 and mixes with the primary oxygen in the oxygen-side flow channel 12, thereby reducing the hydrogen content in the primary oxygen in the oxygen-side flow channel 12, so that the hydrogen content in the primary oxygen in the oxygen-side flow channel 12 always meets the preset standard and is not restricted by the production load, fundamentally solving the problem of the production safety of the electrolyzer. The electrolyzer can produce safely and stably within the full load range, enabling it to more fully adapt to the wide-range fluctuations of renewable energy output, significantly improving the effective utilization rate of renewable energy power generation, and at the same time avoiding problems such as low lifespan and poor reliability caused by frequent start-stop of the electrolyzer.

[0043] It can be understood that the preset standard for the initial oxygen and hydrogen content in the oxygen side flow channel 12 can be formulated based on actual safe production requirements. For example, the preset standard can be a threshold range with a lower limit of X1 and an upper limit of X2. When the hydrogen content in the initial oxygen reaches X1, an alarm is triggered, and when the hydrogen content in the initial oxygen reaches X2, the machine is shut down to ensure safe production. Considering a certain safety margin, preferably, X1 is 1.5% and X2 is 1.8%. In addition, the non-combustible gases used for the dilution gas include, but are not limited to, nitrogen, pure oxygen, and air.

[0044] It can be understood that the size specifications of the electrolytic cell body 10 and the number of electrolytic cells 11 in the electrolytic cell body 10 can be adaptively designed according to actual production capacity requirements, and no specific limitations are imposed in the embodiments of the present invention.

[0045] In one embodiment of the present invention, a plurality of electrolytic cells 11 are stacked and arranged along the length direction of the electrolytic cell body 10. Each electrolytic cell 11 includes a plate 110, an anode electrode 111, a diaphragm 112, a cathode electrode 113, and a plate 110 that are sequentially pressed along the length direction of the electrolytic cell body 10. Among them, the plates 110 at both ends of the electrolytic cell body 10 are end plates, and the plates 110 between the two end plates are intermediate plates.

[0046] In one embodiment of the present invention, the oxygen side flow channel 12 is arranged along the length direction of the electrolytic cell body 10, and one end penetrates through one of the end plates to form an oxygen side outlet 120.

[0047] Specifically, oxygen air holes and first grooves can be provided on the plate 110. Among them, the oxygen air holes penetrate both sides of the plate 110. One end of the first groove is in communication with the oxygen air hole, and the other end extends along the radial direction of the oxygen air hole. The positions of the oxygen air holes on adjacent plates 110 correspond to each other. When the electrolytic cell body 10 is assembled, the adjacent plates 110 are stacked and sealed, so that the oxygen air holes on the plurality of plates 110 are spliced to form an oxygen side flow channel 12 extending along the length direction of the electrolytic cell body 10, and the connection between the oxygen side flow channel 12 and the anode side of each electrolytic cell 11 is realized through the first groove.

[0048] In one embodiment of the present invention, the inlet of the dilution gas flow channel 13 is arranged on the other end plate, and the outlet extends along the length direction of the electrolytic cell body 10 and is in communication with the other end of the oxygen side flow channel 12 relative to the oxygen side outlet 120. With such a setting, when the hydrogen content in the initial oxygen in the oxygen side flow channel 12 exceeds the standard, the dilution gas can be introduced into the oxygen side flow channel 12 from the end far away from the oxygen side outlet 120, so as to ensure that the dilution gas can be fully mixed with the initial oxygen in each area of the oxygen side flow channel 12, avoid the generation of mixing blind spots and cause the hydrogen content of the local initial oxygen in the oxygen side flow channel 12 to exceed the standard, and further ensure safe production.

[0049] In one embodiment of the present invention, a check structure is provided between the anode side of the electrolysis cell 11 and the oxygen-side flow channel 12, and the check structure is used to enable unidirectional conduction from the anode side to the oxygen-side flow channel 12. It can be understood that when the dilution gas is introduced into the oxygen-side flow channel 12 through the dilution gas flow channel 13, the fluid pressure in the oxygen-side flow channel 12 will inevitably increase. The check structure can prevent the fluid in the oxygen-side flow channel 12 from flowing back to the anode side of the electrolysis cell 11 under the action of pressure, and at the same time ensure that the gas-liquid mixture in the anode side of each electrolysis cell 11 can normally flow into the oxygen-side flow channel 12 and be effectively mixed with the dilution gas, avoiding the problem that the anode side of the electrolysis cell 11 is blocked and the pressure difference between the anode side and the cathode side increases.

[0050] The specific structure and form of the check structure can be set according to actual needs. For example, a one-way opening and closing valve flap or a similar structure can be used to achieve unidirectional conduction from the anode side to the oxygen-side flow channel 12. However, considering the processing difficulty, a Tesla valve (valve catheter) can also be used, that is, by processing a flow channel with a specific shape and structure on the electrode plate 110 to achieve unidirectional conduction from the anode side to the oxygen-side flow channel 12. The specific structure form and working principle of the Tesla valve can refer to the prior art and will not be elaborated in the embodiments of the present invention.

[0051] In one embodiment of the present invention, a check valve 130 is connected to the inlet of the dilution gas flow channel 13. The check valve 130 can achieve unidirectional conduction from the dilution gas source 20 to the dilution gas flow channel 13 to prevent the gas-liquid mixture in the electrolysis cell 11 from flowing back into the dilution gas source 20 under accident conditions and ensure safety.

[0052] Next, other structures of the electrolytic cell body 10 will be described with reference to the drawings.

[0053] Refer to Figure 1 , a hydrogen-side flow channel 14 is further provided in the electrolytic cell body 10. The cathode sides of multiple electrolysis cells 11 are all connected to the hydrogen-side flow channel 14. During the process of electrolyzing water to produce hydrogen, hydrogen is generated on the cathode side of the electrolysis cell 11, and the mixture of hydrogen and alkali solution is discharged from the cathode side of the electrolysis cell 11 and flows into the hydrogen-side flow channel 14. The hydrogen and alkali solution discharged from the cathode sides of multiple electrolysis cells 11 are collected and discharged from the electrolytic cell body 10 after flowing through the hydrogen-side flow channel 14.

[0054] Specifically, the hydrogen-side flow channel 14 is arranged along the length direction of the electrolytic cell body 10 and one end penetrates through one of the end plates to form a hydrogen-side outlet 140.

[0055] Specifically, hydrogen gas passage holes and second grooves can be provided on the electrode plate 110; among them, the hydrogen gas passage holes penetrate through both sides of the electrode plate 110; one end of the second groove communicates with the hydrogen gas passage hole, and the other end extends along the radial direction of the hydrogen gas passage hole. The positions of the hydrogen gas passage holes on the adjacent electrode plates 110 correspond to each other. When the electrolytic cell body 10 is assembled, the adjacent electrode plates 110 are stacked and sealed, so that the hydrogen gas passage holes on the multiple electrode plates 110 are spliced to form a hydrogen-side flow channel 14 extending along the length direction of the electrolytic cell body 10, and the connection between the hydrogen-side flow channel 14 and the cathode side of each electrolytic cell 11 is realized through the second groove.

[0056] In an embodiment of the present invention, an alkali solution flow channel 15 is further provided in the electrolytic cell body 10. The cathode sides and anode sides of the multiple electrolytic cells 11 are both connected to the alkali solution flow channel 15. In actual operation, the alkali solution is distributed to the cathode sides and anode sides of each electrolytic cell 11 through the alkali solution flow channel 15.

[0057] Specifically, the alkali solution flow channel 15 is arranged along the length direction of the electrolytic cell body 10 and one end penetrates through one of the end electrode plates to form an alkali solution inlet 150.

[0058] Specifically, liquid passage holes and third grooves can be provided on the electrode plate 110; among them, the liquid passage holes penetrate through both sides of the electrode plate 110; one end of the third groove communicates with the liquid passage hole, and the other end extends along the radial direction of the liquid passage hole. The positions of the liquid passage holes on the adjacent electrode plates 110 correspond to each other. When the electrolytic cell body 10 is assembled, the adjacent electrode plates 110 are stacked and sealed, so that the liquid passage holes on the multiple electrode plates 110 are spliced to form an alkali solution flow channel 15 extending along the length direction of the electrolytic cell body 10, and the connection between the alkali solution flow channel 15 and the cathode side and anode side of each electrolytic cell 11 is realized through the third groove.

[0059] In an embodiment of the present invention, the adjacent electrode plates 110 are sealed by a gasket 16.

[0060] It should be noted here that the above content is only an elaboration of a part of the structure of the electrolytic cell body 10 in order to better understand the improvement points of the present invention. Of course, in order to realize the electrolysis function of the electrolytic cell, it also includes other structures or components that have not been improved, and its more specific structure can refer to the prior art, which will not be elaborated in the embodiments of the present invention.

[0061] Next, the hydrogen production system provided by the present invention will be described. The hydrogen production system described below can be mutually referred to with the wide-width adjustable alkaline electrolytic cell described above.

[0062] Refer to Figures 1 to 5, A hydrogen production system includes a dilution gas source 20 and at least one alkaline electrolyzer with wide-range adjustment provided in any of the above embodiments; the dilution gas source 20 is connected to the inlet of the dilution gas flow channel 13. When the hydrogen content of the initial oxygen in the oxygen-side flow channel 12 exceeds the standard, the non-combustible dilution gas can be introduced into the oxygen-side flow channel 12 through the dilution gas flow channel 13 by the dilution gas source 20. The dilution gas is mixed with the initial oxygen in the oxygen-side flow channel 12, thereby reducing the hydrogen content of the initial oxygen in the oxygen-side flow channel 12 and fundamentally solving the problem of the production safety of the electrolyzer.

[0063] In one embodiment of the present invention, the hydrogen production system further includes an oxygen separator 30, a hydrogen separator 40, a hydrogen purification system 41, an alkali liquor cooler 50, and a circulation pump 60; wherein, the inlet of the oxygen separator 30 is connected to the oxygen-side outlet 120 of the electrolyzer body 10, and the liquid outlet is sequentially connected to the alkali liquor inlet 150 of the electrolyzer body 10 through the alkali liquor cooler 50 and the circulation pump 60. The alkali liquor discharged from the liquid outlet of the oxygen separator 30 is first cooled by the alkali liquor cooler 50, and then transported to the alkali liquor flow channel 15 by the circulation pump 60 to form a circulation of the alkali liquor. The oxygen separated by the oxygen separator 30 can be directly vented or transported to downstream applications.

[0064] The inlet of the hydrogen separator 40 is connected to the hydrogen-side outlet 140 of the electrolyzer body 10, and the liquid outlet is sequentially connected to the alkali liquor inlet 150 of the electrolyzer body 10 through the alkali liquor cooler 50 and the circulation pump 60. The alkali liquor discharged from the liquid outlet of the hydrogen separator 40 is first cooled by the alkali liquor cooler 50, and then transported to the alkali liquor flow channel 15 by the circulation pump 60 to form a circulation of the alkali liquor. The gas outlet of the hydrogen separator 40 is connected to the inlet of the hydrogen purification system 41, and the hydrogen purification system 41 can purify hydrogen to meet the requirements of downstream applications.

[0065] It should be noted here that the specific structures and working principles of the oxygen separator 30 and the hydrogen separator 40 can refer to the oxygen gas-liquid separator and hydrogen gas-liquid separator in the prior art, and will not be elaborated in the embodiments of the present invention. In addition, according to different working principles, there are various selections for the hydrogen purification system 41. For example, pressure swing adsorption, catalytic deoxidation, palladium membrane diffusion, etc. can be adopted, and specific selections can be made according to actual needs, which are not specifically limited in the embodiments of the present invention.

[0066] In one embodiment of the present invention, the dilution gas source 20 includes a dilution gas supply module, a dilution gas compressor 21, and a dilution gas buffer tank 22 connected in sequence; the outlet of the dilution gas buffer tank 22 is connected to the inlet of the dilution gas flow channel 13.

[0067] Specifically, the dilution gas supply module is used to provide dilution gas; the dilution gas compressor 21 is used to pressurize the dilution gas so that it reaches a specific pressure and can smoothly enter the dilution gas flow channel 13; the dilution gas buffer tank 22 can store the pressurized dilution gas to ensure a continuous supply of dilution gas that meets the pressure standard for the electrolytic cell.

[0068] In some alternative embodiments, the dilution gas is a non-combustible gas, including but not limited to air, pure oxygen, nitrogen, etc. Depending on different requirements and the source of the dilution gas, the structural form of the dilution gas supply module will also vary.

[0069] In one embodiment of the present invention, the dilution gas supply module includes a dilution gas storage tank 23. The dilution gas storage tank 23 is used to store the dilution gas, and its outlet is connected to the dilution gas buffer tank 22 through the dilution gas compressor 21. The dilution gas in the dilution gas storage tank 23 can be supplied by a dilution gas transportation system such as a tanker, or can be supplied by the plant's air separation unit. For example, nitrogen or oxygen separated by the plant's air separation unit can be used as the dilution gas.

[0070] In another embodiment of the present invention, when the dilution gas is pure oxygen, the dilution gas in the dilution gas storage tank 23 can also be supplied by the hydrogen production system itself.

[0071] Specifically, the hydrogen production system further includes an oxygen purification system 31; the inlet of the oxygen purification system 31 is connected to the gas outlet of the oxygen separator 30, and the outlet is connected to the dilution gas storage tank 23. The oxygen purification system 31 and the dilution gas storage tank 23 together constitute the above-mentioned dilution gas supply module.

[0072] In practical applications, the gas-liquid mixture discharged from the oxygen side outlet 120 of the electrolytic cell body 10 is subjected to gas-liquid separation by the oxygen separator 30. The separated oxygen enters the oxygen purification system 31. The oxygen purification is used to purify the oxygen discharged from the gas outlet of the oxygen separator 30 to obtain high-purity oxygen with a preset concentration. The high-purity oxygen enters the dilution gas storage tank 23 for storage, thereby providing a continuous supply of dilution gas for the dilution gas buffer tank 22 and realizing oxygen circulation.

[0073] It should be noted here that according to different working principles, there are various choices for the oxygen purification system 31. For example, pressure swing adsorption, membrane separation, dehydrogenation reactors, etc. can be used. Specifically, it can be selected according to actual needs and is not specifically limited in the embodiments of the present invention. In addition, the specific structure of the oxygen purification system 31 can refer to the prior art and is not elaborated in the embodiments of the present invention.

[0074] In one embodiment of the present invention, a pure oxygen pipeline 230 can be added to the dilution gas storage tank 23. The pure oxygen that does not participate in the oxygen cycle can flow through the pure oxygen pipeline 230 to downstream applications (storage, bottling, filling tank trucks, or direct use). For ease of control, flow or pressure control elements can also be provided on the pure oxygen pipeline 230, which will not be elaborated in the embodiments of the present invention.

[0075] In another embodiment of the present invention, when nitrogen is used as the dilution gas, the nitrogen produced by the plant's air separation unit can be used as the dilution gas supply module. When nitrogen is used as the dilution gas, it is more friendly to the shutdown operation and maintenance of the alkaline electrolyzer after experiencing low load. Due to the presence of nitrogen, the dissolved oxygen concentration in the alkali solution decreases, thus significantly reducing the reverse current (both in duration and magnitude) after the alkali solution electrolyzer shuts down, thereby delaying the performance decay process of the electrolyzer.

[0076] The above-mentioned types of dilution gas and the structural form of the dilution gas supply module can be selected according to actual needs, and no specific limitations are made in the embodiments of the present invention. However, it should be noted that different sources of dilution gas will result in certain differences in the mixing ratio of primary oxygen and dilution gas. Specifically, when the dilution gas used is not the high-purity oxygen supplied by the hydrogen production system itself, there is: 。

[0077] When the dilution gas is the high-purity oxygen supplied by the hydrogen production system itself, there is: 。

[0078] Among them, V represents the volume of the gas, and C represents the concentration of the gas.

[0079] Through the above inequalities, the mixing ratio of the dilution gas and the primary oxygen can be determined. According to the mixing ratio of the dilution gas and the primary oxygen and the current flow rate of the primary oxygen, the set flow rate of the dilution gas is determined. The dilution gas source 20 is controlled to introduce the dilution gas into the dilution gas flow channel 13, so that the hydrogen content in the primary oxygen in the oxygen-side flow channel 12 meets the preset standard.

[0080] For ease of regulation, in one embodiment of the present invention, the hydrogen production system further includes a hydrogen content detector 300, which is used to detect the hydrogen content of the primary oxygen in the oxygen-side flow channel 12, so as to dilute it with the dilution gas when the hydrogen content in the primary oxygen exceeds the standard.

[0081] Specifically, the hydrogen content detector 300 can be set at the oxygen-side outlet 120 of the electrolyzer body 10, or at the gas outlet of the oxygen separator 30, and can be specifically selected according to actual needs. In this embodiment, the hydrogen content detector 300 is set at the gas outlet of the oxygen separator 30.

[0082] In one embodiment of the present invention, the hydrogen production system further includes a first pressure transmitter 220 and a second pressure transmitter 301. The first pressure transmitter 220 is connected to the dilution gas buffer tank 22 and is used to detect the pressure of the dilution gas in the dilution gas buffer tank 22. The second pressure transmitter 301 is used to detect the fluid pressure in the oxygen-side flow channel 12. Based on the detection values of the first pressure transmitter 220 and the second pressure transmitter 301 and through a PID feedback mechanism for regulation, the pressure difference between the dilution gas pressure and the fluid pressure is maintained within a set threshold range.

[0083] Through the above technical solution, it can not only ensure that the dilution gas is successfully remixed with the gas-liquid mixture in the oxygen-side flow channel 12 and flows out of the electrolytic cell into the oxygen separator 30, avoiding the situation where the dilution gas pressure is too low to flow into the dilution gas flow channel 13, but also prevent the dilution gas entering the oxygen-side flow channel 12 from having too high a pressure, causing the oxygen + caustic solution gas-liquid mixture to be unable to flow out smoothly from the anode side, resulting in an increase in the pressure on the anode side due to pressure buildup and an increase in the pressure difference with the cathode side.

[0084] It can be understood that the pressure difference between the dilution gas pressure and the fluid pressure can be adjusted according to different types of electrolytic cells, and no specific limitation is made in the embodiments of the present invention.

[0085] Specifically, the second pressure transmitter 301 can be arranged at the oxygen-side outlet 120 of the electrolytic cell body 10 or on the oxygen separator 30. Specifically, it can be selected according to actual needs. In this embodiment, the second pressure transmitter 301 is arranged on the oxygen separator 30.

[0086] Specifically, in order to facilitate the regulation of the pressure of the dilution gas in the dilution gas buffer tank 22, an evacuation pipeline 221 is connected to the buffer tank. When the dilution gas buffer tank 22 is overpressured, it can be evacuated through the evacuation pipeline 221 to reduce the pressure of the dilution gas buffer tank 22.

[0087] Specifically, the evacuation pipeline 221 can be directly connected to the atmosphere for evacuation, or it can be connected to the dilution gas storage tank 23. The dilution gas discharged from the dilution gas buffer tank 22 can enter the dilution gas storage tank 23 for reuse.

[0088] In one embodiment of the present invention, a flow transmitter 70 and a flow regulating valve 80 are provided between the dilution gas buffer tank 22 and the electrolytic cell body 10. The flow regulating valve 80 is interlocked with the hydrogen content detector 300. When the hydrogen content in the oxygen increases, the opening degree of the flow regulating valve 80 is increased, and the flow rate of the dilution gas entering the electrolytic cell increases; when the hydrogen content in the oxygen decreases, the opening degree of the flow regulating valve 80 is decreased, and the flow rate of the dilution gas entering the electrolytic cell decreases.

[0089] It is understandable that in the above electrolytic hydrogen production system, one electrolytic cell can be provided, or N electrolytic cells can be provided according to the production capacity requirements. When N electrolytic cells are provided, the N electrolytic cells can be connected in parallel and share a set of oxygen separator 30, hydrogen separator 40, hydrogen purification system 41, alkali liquor cooler 50, circulation pump 60 and dilution gas source 20. Specifically, the dilution gas buffer tank 22 can be connected to the dilution gas flow channels 13 of different electrolytic cells through multiple dilution gas branch pipes 24. A flow transmitter 70 and a flow regulating valve 80 are provided on each dilution gas branch pipe 24. The flow regulating valve 80 is interlocked with the flow transmitter 70, and the flow regulating valve 80 on each dilution gas branch pipe 24 is adjusted based on the actual production load of different electrolytic cells to meet the safety production requirements of each electrolytic cell under different loads.

[0090] On the other hand, the present invention also provides a control method for an electrolytic hydrogen production system, including the following steps: S1. Obtain the hydrogen content in the primary oxygen generated by the electrolytic cell body 10.

[0091] Specifically, the hydrogen content in the primary oxygen in the oxygen side flow channel 12 is the same as the hydrogen content in the oxygen at the outlet of the oxygen separator 30. Therefore, the hydrogen content in the primary oxygen generated by the electrolytic cell body 10 can be obtained through the hydrogen content detector 300 provided at the outlet of the oxygen separator 30.

[0092] S2. When it is determined that the hydrogen content in the primary oxygen does not meet the set conditions, control the dilution gas source 20 to introduce dilution gas into the dilution gas flow channel 13 so that the hydrogen content in the mixed gas meets the set conditions. Specifically, an inequality can be established according to the hydrogen content in the primary oxygen and the set conditions. When the dilution gas used is not the high-purity oxygen supplied by the hydrogen production system itself, there is: .

[0093] When the dilution gas is the high-purity oxygen supplied by the hydrogen production system itself, there is: .

[0094] Through the above inequality, the mixing ratio of the dilution gas to the primary oxygen can be determined. According to the mixing ratio of the dilution gas to the primary oxygen and the current flow rate of the primary oxygen, the set flow rate of the dilution gas is determined. Control the dilution gas source 20 to introduce dilution gas into the dilution gas flow channel 13 so that the hydrogen content in the primary oxygen in the oxygen side flow channel 12 meets the preset standard.

[0095] S3. When it is determined that the hydrogen content in the primary oxygen meets the set conditions, control the dilution gas source 20 to stop introducing dilution gas into the dilution gas flow channel 13.

[0096] In an embodiment of the present invention, the above step S2 includes: S20. Obtain the fluid pressure in the oxygen side flow channel 12. S21. Based on the fluid pressure, adjust the dilution gas pressure in the dilution gas buffer tank 22 so that the pressure difference between the dilution gas pressure and the fluid pressure remains at a set threshold.

[0097] In this way, it not only ensures that the dilution gas can successfully complete the re - mixing with the gas - liquid mixture in the oxygen side flow channel 12 and flow out of the electrolytic cell into the oxygen separator 30, avoiding the situation where the dilution gas pressure is too low to flow into the dilution gas flow channel 13, but also prevents the dilution gas entering the oxygen side flow channel 12 from having too high a pressure, which causes the oxygen + lye gas - liquid mixture to be unable to flow out smoothly from the anode side, resulting in an increase in the pressure on the anode side due to pressure buildup and an increase in the pressure difference with the cathode side.

[0098] In an embodiment of the present invention, the above - mentioned step S2 further includes: S22. When it is determined that the hydrogen content in the initial oxygen increases, increase the flow rate at the outlet of the dilution gas source 20.

[0099] S23. When it is determined that the hydrogen content in the initial oxygen decreases, decrease the flow rate at the outlet of the dilution gas source 20.

[0100] Through the above - mentioned solution, the flow rate of the dilution gas is regulated based on the hydrogen content in the initial oxygen, so that the hydrogen content in the initial oxygen in the oxygen side flow channel 12 always meets the preset standard.

[0101] Through the wide - range adjustable alkaline electrolytic cell, hydrogen production system and control method provided by the embodiments of the present invention, when the hydrogen content in the initial oxygen in the oxygen side flow channel 12 exceeds the standard due to a decrease in production load, load fluctuation or other reasons, the inlet of the dilution gas flow channel 13 can be connected to the dilution gas source 20. The non - combustible dilution gas enters the oxygen side flow channel 12 through the dilution gas flow channel 13 and mixes with the initial oxygen in the oxygen side flow channel 12, thereby reducing the hydrogen content in the initial oxygen in the oxygen side flow channel 12, making the hydrogen content in the initial oxygen in the oxygen side flow channel 12 always meet the preset standard without being restricted by the production load. Fundamentally, the problem of the production safety of the electrolytic cell is solved. The electrolytic cell can operate safely and stably within the full - load range, enabling it to better adapt to the wide - range fluctuations of renewable energy output, greatly improving the effective utilization rate of renewable energy power generation, and at the same time avoiding problems such as low life and poor reliability caused by frequent start - stop of the electrolytic cell.

[0102] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An alkaline electrolyzer with wide-width adjustment, characterized in that, Comprising: An electrolytic cell body (10); The electrolytic cell body (10) includes a plurality of electrolytic compartments (11), an oxygen side flow channel (12) is arranged in the electrolytic cell body (10), and the anode sides of the plurality of electrolytic compartments (11) are all connected to the oxygen side flow channel (12); A dilution gas flow channel (13) is further arranged in the electrolytic cell body (10), the outlet of the dilution gas flow channel (13) is connected to the oxygen side flow channel (12), and the inlet is adapted to be connected to a dilution gas source (20), and the dilution gas source (20) is adapted to provide a non-combustible dilution gas.

2. The wide-width adjustable alkaline electrolytic cell according to claim 1, characterized in that, The plurality of electrolytic compartments (11) are stacked and arranged along the length direction of the electrolytic cell body (10); Each electrolytic compartment (11) includes plates (110), an anode electrode (111), a diaphragm (112), a cathode electrode (113) and plates (110) that are sequentially pressed along the length direction of the electrolytic cell body (10).

3. The wide-width adjustable alkaline electrolyzer according to claim 2, wherein, The plates (110) located at both ends of the electrolytic cell body (10) are end plates (110), and the plates (110) located between the two end plates (110) are intermediate plates (110); The oxygen side flow channel (12) is arranged along the length direction of the electrolytic cell body (10) and one end penetrates through one of the end plates (110) to form an oxygen side outlet (120); The inlet of the dilution gas flow channel (13) is arranged on the other end plate (110), and the outlet extends along the length direction of the electrolytic cell body (10) and is communicated with the other end of the oxygen side flow channel (12) relative to the oxygen side outlet (120).

4. The wide-width adjustable alkaline electrolyzer according to any one of claims 1 to 3, characterized in that, A check structure is arranged between the anode side of the electrolytic compartment (11) and the oxygen side flow channel (12), and the check structure is used to make the anode side to the oxygen side flow channel (12) conduct unidirectionally.

5. The hydrogen production system according to claim 1, characterized in that, A check valve is connected to the inlet of the dilution gas flow channel (13).

6. A hydrogen production system, characterized in that, Including a dilution gas source (20) and at least one wide-width adjustable alkaline electrolytic cell as described in any one of claims 1-5; the dilution gas source (20) is connected to the inlet of the dilution gas flow channel (13).

7. The hydrogen production system according to claim 6, wherein The dilution gas source (20) includes a dilution gas supply module, a dilution gas compressor (21) and a dilution gas buffer tank (22) that are connected in sequence; The outlet of the dilution gas buffer tank (22) is connected to the inlet of the dilution gas flow channel (13).

8. The hydrogen production system according to claim 7, wherein, Further comprising: An oxygen separator (30) with an inlet connected to the oxygen side outlet (120) of the electrolytic cell body (10); An oxygen purification system (31) with an inlet connected to the outlet of the oxygen separator (30) and an outlet connected to the dilution gas storage tank (23), constituting the dilution gas supply module.

9. The hydrogen production system according to claim 8, characterized in that, A first pressure transmitter (220) is arranged on the dilution gas buffer tank (22), and a second pressure transmitter (301) is arranged on the oxygen separator (30); And / or, a hydrogen content detector (300) is connected to the outlet of the oxygen separator (30).

10. A control method for an electrolytic hydrogen production system, characterized in that, Including the following steps: Obtaining the hydrogen content in the initial oxygen generated by the electrolytic cell body (10); When it is determined that the hydrogen content in the initial oxygen does not meet the set conditions, control the dilution gas source (20) to introduce dilution gas into the dilution gas flow channel (13) so that the hydrogen content in the mixed gas meets the set conditions; When it is determined that the hydrogen content in the initial oxygen meets the set conditions, control the dilution gas source (20) to stop introducing dilution gas into the dilution gas flow channel (13); Preferably, controlling the dilution gas source (20) to introduce dilution gas into the dilution gas flow channel (13) includes: Obtain the fluid pressure in the oxygen-side flow channel (12); Based on the fluid pressure, adjust the dilution gas pressure in the dilution gas buffer tank (22) so that the pressure difference between the dilution gas pressure and the fluid pressure remains at a set threshold; Preferably, controlling the dilution gas source (20) to introduce dilution gas into the dilution gas flow channel (13) further includes: When it is determined that the hydrogen content in the initial oxygen increases, increase the flow rate at the outlet of the dilution gas source (20); When it is determined that the hydrogen content in the initial oxygen decreases, decrease the flow rate at the outlet of the dilution gas source (20).

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