Alkaline water electrolysis hydrogen production system

Abstract

The invention discloses an alkaline water electrolysis hydrogen production system, which comprises an alkaline electrolytic bath, a hydrogen generator, a hydrogen generator, a hydrogen generator and a hydrogen generator, and the alkaline electrolytic bath is used for electrolyzing alkaline liquor to generate hydrogen and oxygen; the hydrogen separation module is connected with a hydrogen outlet of the alkaline electrolytic bath; the oxygen separation module is connected with an oxygen outlet of the alkaline electrolytic bath; the hydrogen side alkali liquor circulation module is used for independently cooling and circulating the alkali liquor separated by the hydrogen separation module; the oxygen side alkali liquor circulation module is used for independently cooling and circulating the alkali liquor separated by the oxygen separation module; and the pressure self-balancing device is used for balancing the pressure between the hydrogen separation module and the oxygen separation module. By means of the scheme, completely independent circulation from gas separation to alkali liquor cooling on the two sides of hydrogen and oxygen is achieved, possible gas cross contamination is fundamentally eradicated, increase of the concentration of hydrogen in oxygen and the concentration of oxygen in hydrogen is effectively inhibited, and therefore the intrinsic safety of the system is greatly improved. And meanwhile, hydrogen and oxygen with higher purity can be obtained on the premise of ensuring safety.

Description

Technical Field

[0001] This application generally relates to the field of hydrogen production technology. More specifically, this application relates to an alkaline water electrolysis hydrogen production system. Background Technology

[0002] Alkaline water electrolysis for hydrogen production is an important hydrogen production technology, and the safety of its system is crucial for ensuring its stable operation and large-scale application. In traditional alkaline water electrolysis hydrogen production processes, the hydrogen concentration in oxygen, the oxygen concentration in hydrogen, system pressure, and the liquid level difference in the hydrogen-oxygen separator are key indicators for evaluating system safety and stability. When the concentration of hydrogen mixed with oxygen in the system is too high (hydrogen in oxygen), it significantly increases the risk of explosion of the hydrogen-oxygen mixture, potentially leading to serious safety accidents. Simultaneously, the concentration of oxygen mixed with hydrogen (oxygen in hydrogen) not only affects the purity of the final hydrogen product, but excessively high concentrations also pose safety hazards. Furthermore, in traditional alkaline water electrolysis hydrogen production systems, the system operating pressure and the liquid level difference control of the hydrogen-oxygen separator are closely related and highly coupled; fluctuations in either can affect the other. Unstable control can easily trigger a protective shutdown (trip), affecting the continuity of production.

[0003] In traditional alkaline water electrolysis hydrogen production systems, the phenomenon of gas cross-permeation (i.e., oxygen-in-hydrogen and hydrogen-in-oxygen) is mainly affected by various factors such as the permeability of the electrolyzer diaphragm, electrode reaction conditions, and system sealing performance. High diaphragm permeability, excessive current density, or improper operation can all lead to hydrogen escaping into the oxygen side or vice versa, thereby increasing the concentration of hydrogen in oxygen and oxygen in hydrogen. In addition, uneven electrolyte circulation, system pressure fluctuations, fluctuations in the liquid level difference of the hydrogen-oxygen separator, and low efficiency of the gas purification device may further exacerbate this problem. To solve this problem, industry improvements mainly focus on developing new equipment (such as new diaphragms and new electrodes) or optimizing control strategies, but these methods often involve large investments, long cycles, and are difficult to see results in the short term.

[0004] In view of this, there is an urgent need to provide an alkaline water electrolysis hydrogen production scheme to solve the above problems and improve the system safety of alkaline water electrolysis hydrogen production. Summary of the Invention

[0005] In order to at least solve one or more of the technical problems mentioned above, this application proposes an alkaline water electrolysis hydrogen production scheme in several aspects.

[0006] This application provides an alkaline water electrolysis hydrogen production system, comprising: an alkaline electrolyzer for electrolyzing alkaline solution to generate hydrogen and oxygen; a hydrogen separation module connected to the hydrogen outlet of the alkaline electrolyzer; an oxygen separation module connected to the oxygen outlet of the alkaline electrolyzer; a hydrogen-side alkaline solution circulation module for independently cooling and circulating the alkaline solution separated by the hydrogen separation module; an oxygen-side alkaline solution circulation module for independently cooling and circulating the alkaline solution separated by the oxygen separation module; and a pressure self-balancing device for balancing the pressure between the hydrogen separation module and the oxygen separation module.

[0007] In some embodiments, the hydrogen separation module includes: an oxygen filter with its inlet connected to the hydrogen outlet of the alkaline electrolyzer for absorbing oxygen contained in the gas-liquid mixture flowing out from the hydrogen side of the alkaline electrolyzer; and a hydrogen separator connected to the outlet of the oxygen filter for separating hydrogen from alkaline solution.

[0008] In some embodiments, the oxygen separation module includes: a hydrogen filter with its inlet connected to the oxygen outlet of the alkaline electrolyzer for absorbing hydrogen contained in the gas-liquid mixture flowing out from the oxygen side of the alkaline electrolyzer; and an oxygen separator connected to the outlet of the hydrogen filter for separating oxygen from the alkaline solution.

[0009] In some embodiments, the pressure self-balancing device includes: a gas pipeline with its two ends connected to the upper gas phase space of the hydrogen separator and the oxygen separator, respectively; and a piston disposed in the gas pipeline, the piston being used to isolate hydrogen and oxygen and to balance the pressure in the hydrogen separator and the oxygen separator at both ends of the gas pipeline by moving.

[0010] In some embodiments, the hydrogen-side alkali circulation module includes: a first heat exchanger connected to the lower part of the hydrogen separator, and a first alkali circulation pump connected to the first heat exchanger.

[0011] In some embodiments, the oxygen-side alkali circulation module includes: a second heat exchanger connected to the lower part of the oxygen separator, and a second alkali circulation pump connected to the second heat exchanger.

[0012] In some embodiments, a first heat exchanger cools the hydrogen-side alkaline solution flowing out of the hydrogen separator, and a second heat exchanger cools the oxygen-side alkaline solution flowing out of the oxygen separator. The cooled hydrogen-side alkaline solution and oxygen-side alkaline solution are then mixed and stored together in an alkaline buffer tank via a first alkaline solution circulation pump and a second alkaline solution circulation pump.

[0013] In some embodiments, the outlet of the alkali buffer tank is connected to a third alkali circulation pump, which is used to transport the mixed hydrogen-side alkali and oxygen-side alkali back to the inlet of the alkaline electrolyzer.

[0014] In some embodiments, the hydrogen separation module further includes: a hydrogen heat exchanger for cooling the hydrogen separated from the hydrogen separator; a hydrogen scrubber for washing away alkaline substances entrained in the cooled hydrogen; a hydrogen oxygen monitoring instrument for monitoring the hydrogen oxygen concentration at the outlet of the hydrogen scrubber; a first temperature instrument for monitoring the temperature at the hydrogen outlet of the alkaline electrolyzer; a first level gauge for monitoring the liquid level inside the hydrogen separator; and a first pressure monitoring instrument for monitoring the pressure inside the hydrogen separator.

[0015] In some embodiments, the oxygen separation module further includes: an oxygen heat exchanger for cooling the oxygen separated from the oxygen separator; an oxygen scrubber for washing away alkaline substances entrained in the cooled oxygen; an oxygen hydrogen monitoring instrument for monitoring the hydrogen concentration in the oxygen at the outlet of the oxygen scrubber; a second temperature instrument for monitoring the temperature at the oxygen outlet of the alkaline electrolytic cell; a second level gauge for monitoring the liquid level inside the oxygen separator; and a second pressure monitoring instrument for monitoring the pressure inside the oxygen separator.

[0016] Through the alkaline water electrolysis hydrogen production scheme provided above, this embodiment of the application achieves completely independent circulation of hydrogen and oxygen from gas separation to alkaline cooling. This fundamentally eliminates the potential for cross-contamination of gases that can occur in traditional shared circulation pipelines, effectively suppressing the increase in hydrogen concentration in oxygen and oxygen concentration in hydrogen, thereby significantly improving the inherent safety of the system. Simultaneously, the pressure self-balancing device can automatically and stably maintain the pressure difference between the two sides, avoiding the risk of system shutdown due to pressure fluctuations, enhancing operational stability and reliability, and ultimately obtaining hydrogen and oxygen with higher purity while ensuring safety.

[0017] Furthermore, in some embodiments, a pre-positioned, targeted gas filter is added at the gas outlet of the electrolyzer, i.e., before the gas enters the main separator. This filter actively absorbs and removes trace amounts of oxygen mixed in from the hydrogen side and trace amounts of hydrogen mixed in from the oxygen side at the earliest possible time. This proactive intervention significantly reduces the concentrations of hydrogen in oxygen and oxygen in hydrogen in the subsequent system, not only significantly improving the purity of crude hydrogen and crude oxygen, but more importantly, fundamentally reducing the risk of forming an explosive mixture, providing a solid and efficient first line of defense for the safe operation of the entire hydrogen production system.

[0018] Furthermore, in some embodiments, a pressure self-balancing device is employed, constructing a highly ingenious purely physical regulating mechanism through a pipe connecting the gas phase space of the hydrogen and oxygen separator and an internal moving piston. This mechanism effectively isolates hydrogen and oxygen, preventing direct mixing, and automatically and in real-time balances the pressure on both sides using the free movement of the piston. The greatest advantage of this design lies in its simplicity, reliability, and lack of external control. It converts passive pressure difference into mechanical piston movement, thereby replacing complex electronic sensors and control valves. This not only reduces costs and potential points of failure but, more importantly, enables instantaneous response to pressure fluctuations, effectively preventing the risk of damage to the electrolyzer diaphragm due to excessive pressure difference. This provides an efficient guarantee for the long-term stable and safe operation of the entire hydrogen production system.

[0019] Furthermore, in some embodiments, independent heat exchange cycles and centralized reflux paths are constructed for the hydrogen and oxygen-side alkaline solutions. This allows the high-temperature alkaline solutions flowing from the hydrogen and oxygen separators to undergo precise, non-interfering cooling via their respective independent heat exchangers and circulating pumps before converging into a shared alkaline buffer tank. Through mixing and storage in the buffer tank, potential flow and temperature differences between the hydrogen and oxygen streams are effectively balanced, ensuring a uniform and stable temperature of the alkaline solution returning to the electrolyzer. This achieves efficient heat management while completely isolating the high-temperature alkaline solution containing trace amounts of the opposite gas from any potential contact during the cooling process, thereby further enhancing system safety and ensuring process consistency in the returned alkaline solution. Attached Figure Description

[0020] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein:

[0021] Figure 1 An exemplary structural block diagram of an alkaline water electrolysis hydrogen production system according to an embodiment of this application is shown;

[0022] Figure 2 A structural diagram of an alkaline water electrolysis hydrogen production system according to an embodiment of this application is shown. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] It should be understood that the terms "comprising" and "including" used in the specification and claims of this application indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this specification and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0026] Figure 1 An exemplary structural block diagram of an alkaline water electrolysis hydrogen production system 100 according to an embodiment of this application is shown.

[0027] like Figure 1 As shown, the alkaline water electrolysis hydrogen production system 100 includes an alkaline electrolyzer 110, a hydrogen separation module 120, an oxygen separation module 130, a hydrogen-side alkaline solution circulation module 140, an oxygen-side alkaline solution circulation module 150, and a pressure self-balancing device 160.

[0028] Specifically, the alkaline electrolytic cell 110 is used to electrolyze alkaline solution to produce hydrogen and oxygen.

[0029] Specifically, the hydrogen separation module 120 is connected to the hydrogen outlet of the alkaline electrolyzer 110.

[0030] Specifically, the oxygen separation module 130 is connected to the oxygen outlet of the alkaline electrolyzer 110.

[0031] Specifically, the oxygen-side alkali circulation module 150 is used to independently cool and circulate the alkali solution separated by the hydrogen separation module 120.

[0032] Specifically, the oxygen-side alkali circulation module 150 is used to independently cool and circulate the alkali solution separated by the oxygen separation module 130.

[0033] Specifically, the pressure self-balancing device 160 is used to balance the pressure between the hydrogen separation module 120 and the oxygen separation module 130.

[0034] The following is combined with Figure 2 The specific composition and / or working process of the alkaline electrolytic cell 110, hydrogen separation module 120, oxygen separation module 130, hydrogen-side alkaline solution circulation module 140, oxygen-side alkaline solution circulation module 150, and pressure self-balancing device 160 are explained in detail.

[0035] In the embodiments of this application, the hydrogen separation module 120 includes an oxygen filtration device 121, a hydrogen separator 122, a hydrogen heat exchanger 123, a hydrogen scrubber 124, a hydrogen oxygen monitoring instrument 125, a first temperature instrument 126, a first level gauge 127, a first pressure monitoring instrument 128, and a hydrogen output valve 129.

[0036] Specifically, the inlet of the oxygen filter 121 is connected to the hydrogen outlet of the aforementioned alkaline electrolyzer 110, and is used to absorb the oxygen contained in the gas-liquid mixture flowing out from the hydrogen side of the alkaline electrolyzer 110. The hydrogen separator 122 is connected to the outlet of the oxygen filter 121 and is used to separate hydrogen from the alkaline solution. The hydrogen heat exchanger 123 is used to cool the hydrogen separated from the hydrogen separator 122. The hydrogen scrubber 124 is used to wash away alkaline substances entrained in the cooled hydrogen. The hydrogen-oxygen monitoring instrument 125 is installed at the outlet of the hydrogen scrubber 124 and is used to monitor the hydrogen-oxygen concentration at the outlet of the hydrogen scrubber 124. The first temperature instrument 126 is installed at the hydrogen outlet of the alkaline electrolyzer 110 and is used to monitor the temperature of the hydrogen outlet of the alkaline electrolyzer 110. The first level gauge 127 is installed at the outlet of the hydrogen separator 122 and is used to monitor the liquid level inside the hydrogen separator 122. The first pressure monitoring instrument 128 is installed at the outlet of the hydrogen separator 122 to monitor the pressure inside the hydrogen separator 122. The hydrogen output valve 129 is installed on the output pipeline of the hydrogen scrubber 124 to control the output of hydrogen after passing through the hydrogen scrubber 124.

[0037] In the embodiments of this application, during the operation of the hydrogen separation module 120, a gas-liquid mixture consisting of a large amount of hydrogen, a small amount of oxygen, and alkaline solution flowing out of the alkaline electrolysis cell 110 enters the oxygen filtration device 121. The oxygen filtration device 121 actively absorbs and removes the trace amounts of oxygen mixed in, thereby reducing the oxygen concentration in the hydrogen. This is the first key line of defense to ensure system safety and improve purity. Subsequently, the mixture, which has been preliminarily purified by the oxygen filtration device 121, enters the hydrogen separator 122, where the hydrogen and alkaline solution are separated by gravity. At the same time, the liquid level and pressure inside the hydrogen separator 122 are monitored by the first liquid level gauge 127 and the first pressure monitoring instrument 128, and water is added to the hydrogen separator 122 according to the liquid level. The crude hydrogen separated by the hydrogen separator 122 is then cooled down by the hydrogen heat exchanger 123 and then enters the hydrogen scrubber 124 to wash away residual alkaline substances. Finally, the hydrogen processed by the hydrogen scrubber 124 flows through the hydrogen oxygen monitoring instrument 125 for final quality control. The reading of this instrument will serve as the basis for decision-making, determining whether the batch of hydrogen is qualified to pass through the hydrogen output valve 129 into the subsequent purification unit, or whether it needs to be safely vented due to excessive oxygen content. This achieves a complete closed-loop process from source purification, separation, and purification to final quality monitoring.

[0038] In the embodiments of this application, the oxygen separation module 130 includes a hydrogen filtration device 131, an oxygen separator 132, an oxygen heat exchanger 133, an oxygen scrubber 134, an oxygen-hydrogen monitoring instrument 135, a second temperature instrument 136, a second level gauge 137, a second pressure monitoring instrument 138, and an oxygen output valve 139.

[0039] Specifically, the inlet of the hydrogen filtration device 131 is connected to the oxygen outlet of the alkaline electrolyzer 110, used to absorb hydrogen contained in the gas-liquid mixture flowing out from the oxygen side of the alkaline electrolyzer 110. An oxygen separator 132 is connected to the outlet of the hydrogen filtration device 131, used to separate oxygen from the alkaline solution. An oxygen heat exchanger 133 is used to cool the oxygen separated from the oxygen separator 132. An oxygen scrubber 134 is used to wash away alkaline substances entrained in the cooled oxygen. An oxygen-hydrogen monitoring instrument 135 is installed at the outlet of the oxygen scrubber 134, used to monitor the hydrogen concentration in the oxygen at the outlet of the oxygen scrubber 134. A second temperature instrument 136 is installed at the oxygen outlet of the alkaline electrolyzer 110, used to monitor the temperature at the oxygen outlet of the alkaline electrolyzer 110. A second level gauge 137 is installed at the outlet of the oxygen separator 132, used to monitor the liquid level inside the oxygen separator 132. A second pressure monitoring instrument 138 is installed at the outlet of the oxygen separator 132, used to monitor the pressure inside the oxygen separator 132. The oxygen output valve 139 is installed on the output pipeline of the oxygen scrubber 134 and is used to control the output of oxygen after passing through the oxygen scrubber 134.

[0040] In the embodiments of this application, during the operation of the oxygen separation module 130, a gas-liquid mixture consisting of a large amount of oxygen, a small amount of hydrogen, and alkaline solution flowing out of the alkaline electrolysis cell 110 enters the hydrogen filtration device 131. The hydrogen filtration device 131 actively absorbs and removes the trace amounts of hydrogen mixed in, thereby reducing the hydrogen concentration in the oxygen. This is the first key line of defense to ensure system safety and improve purity. Subsequently, the mixture, which has been preliminarily purified by the hydrogen filtration device 131, enters the oxygen separator 132, where the oxygen and alkaline solution are separated by gravity. At the same time, the liquid level and pressure inside the oxygen separator 132 are monitored by the second liquid level gauge 137 and the second pressure monitoring instrument 138, and water is added to the oxygen separator 132 according to the liquid level. The crude oxygen separated by the oxygen separator 132 is then cooled down by the oxygen heat exchanger 133 and then enters the oxygen scrubber 134 to wash away residual alkaline substances. Finally, the oxygen processed by the oxygen scrubber 134 flows through the hydrogen-in-oxygen-in-hydrogen monitoring instrument 135 for final quality control. The reading of this instrument will serve as the basis for decision-making, determining whether this batch of oxygen is qualified to pass through the oxygen output valve 139 into the subsequent purification unit, or whether it needs to be safely vented due to excessive oxygen content. This achieves a complete closed-loop process from source purification, separation, and purification to final quality monitoring.

[0041] The hydrogen separation module 120 and oxygen separation module 130 perform multi-stage, closed-loop fine processing on the raw gas-liquid mixture flowing from the electrolyzer, ensuring that the final output hydrogen and oxygen meet high purity and safety standards. First, by installing dedicated filtration devices at the source of each process to actively absorb and remove each other's gases (i.e., oxygen in hydrogen and hydrogen in oxygen), the risk of forming explosive gas mixtures is fundamentally eliminated, achieving inherent safety at the system level. Second, a standardized separation-cooling-washing process is adopted to systematically remove alkali and lower the temperature, ensuring stable gas quality and the safety of subsequent equipment. Finally, by integrating comprehensive temperature, pressure, liquid level monitoring, and final gas purity monitoring, it endows the system with powerful process control and quality assurance capabilities, ensuring a high degree of automation, stability, and reliability throughout the hydrogen production process.

[0042] In an embodiment of this application, the pressure self-balancing device 160 includes a gas pipe 161 and a piston 162 disposed within the gas pipe. The two ends of the gas pipe 161 are respectively connected to the upper gas phase spaces of the aforementioned hydrogen separator 122 and the aforementioned oxygen separator 132. The piston 162 disposed within the gas pipe is used to isolate hydrogen and oxygen, and its movement balances the pressure within the aforementioned hydrogen separator 122 and the aforementioned oxygen separator 132 at both ends of the gas pipe 161.

[0043] Specifically, the two ends of the gas pipe 161 are connected to the upper gas phase space of the aforementioned hydrogen separator 122 and the aforementioned oxygen separator 132, respectively. This position ensures that only the gas (hydrogen and oxygen) separated from the alkali solution can enter the gas pipe 161, while the liquid alkali solution remains in the lower part of the aforementioned hydrogen separator 122 and the aforementioned oxygen separator 132 and will not enter.

[0044] Specifically, the piston 162, installed inside the gas pipeline, divides the interior of the gas pipeline 161 into two completely independent gas chambers: one side is connected to the hydrogen separator 122 and filled with hydrogen, while the other side is connected to the oxygen separator 132 and filled with oxygen. The piston has extremely high airtightness, ensuring that hydrogen and oxygen will not permeate or mix under any circumstances, which is a fundamental prerequisite for ensuring system safety.

[0045] In the embodiments of this application, during the operation of the pressure self-balancing device 160, when the hydrogen and oxygen pressures on both sides are equal, the gas thrust on both sides of the piston 162 located in the gas pipeline is completely equal. Therefore, the piston 162 located in the gas pipeline remains stationary, typically residing in the middle position of the gas pipeline 161. The pressure self-balancing device 160 is in a static equilibrium state. When the hydrogen and oxygen pressures on both sides are unequal, for example, the hydrogen pressure is greater than the oxygen pressure, the side of the piston 162 connected to the hydrogen separator 122 in the gas pipeline will experience a greater thrust than the oxygen side. This unbalanced thrust will immediately push the piston 162 in the gas pipeline, causing it to move towards the lower-pressure oxygen side. On the hydrogen side, due to the movement of the piston, the volume of the pipeline on its side increases, and the total effective volume of the hydrogen side increases, resulting in a decrease in its pressure. On the oxygen side, due to the piston moving in this direction, the volume of the pipeline on its side decreases. Similarly, the gas volume decreases, resulting in an increase in its pressure. The piston 162 inside the gas pipeline will continue to move until the pressure on both sides of it becomes equal again. At this point, the forces acting on the piston are rebalanced, the piston 162 inside the gas pipeline stops moving, and the system returns to a new equilibrium position.

[0046] The pressure self-balancing device 160, through an ingenious, purely mechanical piston design, achieves dynamic, real-time, and fully automatic pressure balancing of the hydrogen and oxygen separator. Firstly, it significantly enhances system safety. Its airtight piston physically isolates hydrogen and oxygen, eliminating the risk of mixing. Simultaneously, its pressure balancing function effectively prevents damage to equipment (especially the electrolyzer diaphragm) caused by excessive pressure differences between the two sides of the system, fundamentally eliminating a major safety hazard. Secondly, it achieves extremely high reliability and operational stability. As a passive, unpowered device, it does not rely on any external energy source or complex electronic control. It responds instantly and eliminates pressure fluctuations based solely on basic physical principles. Therefore, it not only operates extremely stably and reliably but also simplifies the system structure, providing a solid guarantee for the stable and efficient operation of the entire hydrogen production system.

[0047] In the embodiments of this application, the hydrogen-side alkali circulation module 140 includes a first heat exchanger 141 connected to the lower part of the aforementioned hydrogen separator 122 and a first alkali circulation pump 142 connected to the first heat exchanger 141.

[0048] In the embodiments of this application, the oxygen-side alkali circulation module 150 includes a second heat exchanger 151 connected to the lower part of the aforementioned oxygen separator 132 and a second alkali circulation pump 152 connected to the second heat exchanger 151.

[0049] By setting up independent heat exchangers and circulating pumps for the hydrogen and oxygen sides respectively, it can efficiently and specifically cool down the high-temperature alkaline solutions separated from both sides, ensuring that the heat is removed in a timely manner.

[0050] In the embodiments of this application, the first heat exchanger 141 cools the hydrogen-side alkaline solution flowing out of the hydrogen separator 122, and the second heat exchanger 151 cools the oxygen-side alkaline solution flowing out of the oxygen separator 132. The cooled hydrogen-side alkaline solution and oxygen-side alkaline solution are respectively fed into the alkaline buffer tank 170 for mixing and storage through the first alkaline solution circulation pump 142 and the second alkaline solution circulation pump 152.

[0051] In the embodiments of this application, the outlet of the alkali buffer tank 170 is connected to a third alkali circulation pump 171, which is used to transport the mixed hydrogen-side alkali and oxygen-side alkali back to the inlet of the aforementioned alkaline electrolytic cell 110. A third temperature instrument 172 is installed at the outlet of the alkali buffer tank 170 to monitor the temperature at the outlet of the alkali buffer tank 170. An alkali flow monitoring instrument 173 is installed between the alkali buffer tank 170 and the alkaline electrolytic cell 110 to monitor the flow rate of alkali flowing from the alkali buffer tank 170 into the alkaline electrolytic cell 110.

[0052] The alkali buffer tank stores and mixes the two reflux alkali solutions, playing an automatic balancing role. It effectively solves the possible differences in flow and temperature between the two alkali solutions, ensuring that the alkali solution finally returned to the electrolytic cell has a stable flow and uniform temperature.

[0053] By setting up a unified circulating pump, temperature and flow monitoring instruments on the main circuit, the system simplifies the control and monitoring of key parameters at the electrolyzer inlet, greatly enhances the reliability, stability and controllability of the alkali circulation system, and provides a solid guarantee for the long-term efficient operation of the electrolyzer.

[0054] In summary, through the alkaline water electrolysis hydrogen production scheme provided above, the embodiments of this application achieve completely independent circulation of hydrogen and oxygen from gas separation to alkaline cooling. This fundamentally eliminates the potential for cross-contamination of gases that can occur in traditional shared circulation pipelines, effectively suppressing the increase in hydrogen concentration in oxygen and oxygen concentration in hydrogen, thereby significantly improving the inherent safety of the system. Simultaneously, the pressure self-balancing device can automatically and stably maintain the pressure difference between the two sides, avoiding the risk of system shutdown due to pressure fluctuations, enhancing operational stability and reliability, and ultimately obtaining hydrogen and oxygen with higher purity while ensuring safety.

[0055] Furthermore, in some embodiments, a pre-positioned, targeted gas filter is added at the gas outlet of the electrolyzer, i.e., before the gas enters the main separator. This filter actively absorbs and removes trace amounts of oxygen mixed in from the hydrogen side and trace amounts of hydrogen mixed in from the oxygen side at the earliest possible time. This proactive intervention significantly reduces the concentrations of hydrogen in oxygen and oxygen in hydrogen in the subsequent system, not only significantly improving the purity of crude hydrogen and crude oxygen, but more importantly, fundamentally reducing the risk of forming an explosive mixture, providing a solid and efficient first line of defense for the safe operation of the entire hydrogen production system.

[0056] Furthermore, in some embodiments, a pressure self-balancing device is employed, constructing a highly ingenious purely physical regulating mechanism through a pipe connecting the gas phase space of the hydrogen and oxygen separator and an internal moving piston. This mechanism effectively isolates hydrogen and oxygen, preventing direct mixing, and automatically and in real-time balances the pressure on both sides using the free movement of the piston. The greatest advantage of this design lies in its simplicity, reliability, and lack of external control. It converts passive pressure difference into mechanical piston movement, thereby replacing complex electronic sensors and control valves. This not only reduces costs and potential points of failure but, more importantly, enables instantaneous response to pressure fluctuations, effectively preventing the risk of damage to the electrolyzer diaphragm due to excessive pressure difference. This provides an efficient guarantee for the long-term stable and safe operation of the entire hydrogen production system.

[0057] Furthermore, in some embodiments, independent heat exchange cycles and centralized reflux paths are constructed for the hydrogen and oxygen-side alkaline solutions. This allows the high-temperature alkaline solutions flowing from the hydrogen and oxygen separators to undergo precise, non-interfering cooling via their respective independent heat exchangers and circulating pumps before converging into a shared alkaline buffer tank. Through mixing and storage in the buffer tank, potential flow and temperature differences between the hydrogen and oxygen streams are effectively balanced, ensuring a uniform and stable temperature of the alkaline solution returning to the electrolyzer. This achieves efficient heat management while completely isolating the high-temperature alkaline solution containing trace amounts of the opposite gas from any potential contact during the cooling process, thereby further enhancing system safety and ensuring process consistency in the returned alkaline solution.

[0058] While numerous embodiments of this application have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will arise for those skilled in the art without departing from the spirit and intent of this application. It should be understood that various alternatives to the embodiments of this application described herein may be employed in the practice of this application. The appended claims are intended to define the scope of protection of this application and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. An alkaline water electrolysis hydrogen production system, characterized in that, include: An alkaline electrolytic cell is used to electrolyze alkaline solutions to produce hydrogen and oxygen. A hydrogen separation module is connected to the hydrogen outlet of the alkaline electrolyzer; An oxygen separation module is connected to the oxygen outlet of the alkaline electrolyzer; The hydrogen-side alkali solution circulation module is used to independently cool and circulate the alkali solution separated by the hydrogen separation module. The oxygen-side alkali solution circulation module is used to independently cool and circulate the alkali solution separated by the oxygen separation module. And a pressure self-balancing device for balancing the pressure between the hydrogen separation module and the oxygen separation module.

2. The alkaline water electrolysis hydrogen production system according to claim 1, characterized in that, The hydrogen separation module includes: An oxygen filtration device, the inlet of which is connected to the hydrogen outlet of the alkaline electrolyzer, is used to absorb the oxygen contained in the gas-liquid mixture flowing out from the hydrogen side of the alkaline electrolyzer. A hydrogen separator, connected to the outlet of the oxygen filtration unit, is used to separate hydrogen from alkaline solution.

3. The alkaline water electrolysis hydrogen production system according to claim 2, characterized in that, The oxygen separation module includes: A hydrogen filtration device, the inlet of which is connected to the oxygen outlet of the alkaline electrolyzer, is used to absorb hydrogen contained in the gas-liquid mixture flowing out from the oxygen side of the alkaline electrolyzer. An oxygen separator, connected to the outlet of the hydrogen filtration unit, is used to separate oxygen from alkaline solution.

4. The alkaline water electrolysis hydrogen production system according to claim 3, characterized in that, The pressure self-balancing device includes: A gas pipeline, the two ends of which are respectively connected to the upper gas phase space of the hydrogen separator and the oxygen separator; A piston is installed inside a gas pipeline to isolate hydrogen from oxygen and to balance the pressure in the hydrogen separator and the oxygen separator at both ends of the gas pipeline by moving the piston.

5. The alkaline water electrolysis hydrogen production system according to claim 3, characterized in that, The hydrogen-side alkali circulation module includes: a first heat exchanger connected to the lower part of the hydrogen separator, and a first alkali circulation pump connected to the first heat exchanger.

6. The alkaline water electrolysis hydrogen production system according to claim 5, characterized in that, The oxygen-side alkali circulation module includes: a second heat exchanger connected to the lower part of the oxygen separator, and a second alkali circulation pump connected to the second heat exchanger.

7. The alkaline water electrolysis hydrogen production system according to claim 6, characterized in that, The first heat exchanger cools the hydrogen-side alkaline solution flowing out of the hydrogen separator, and the second heat exchanger cools the oxygen-side alkaline solution flowing out of the oxygen separator. The cooled hydrogen-side alkaline solution and oxygen-side alkaline solution are then mixed and stored together in an alkaline buffer tank via the first alkaline solution circulation pump and the second alkaline solution circulation pump, respectively.

8. The alkaline water electrolysis hydrogen production system according to claim 7, characterized in that, The outlet of the alkali buffer tank is connected to a third alkali circulation pump, which is used to transport the mixed hydrogen-side alkali and oxygen-side alkali back to the inlet of the alkaline electrolyzer.

9. The alkaline water electrolysis hydrogen production system according to claim 2, characterized in that, The hydrogen separation module also includes: A hydrogen heat exchanger is used to cool down the hydrogen separated from the hydrogen separator. Hydrogen scrubbers are used to wash away alkaline substances carried in cooled hydrogen gas. Hydrogen oxygen monitoring instrument, used to monitor the hydrogen oxygen concentration at the outlet of a hydrogen scrubber; The first temperature instrument is used to monitor the temperature of the hydrogen outlet of the alkaline electrolyzer; The first level gauge is used to monitor the liquid level inside the hydrogen separator; The first pressure monitoring instrument is used to monitor the pressure inside the hydrogen separator.

10. The alkaline water electrolysis hydrogen production system according to claim 3, characterized in that, The oxygen separation module also includes: An oxygen heat exchanger is used to cool the oxygen separated from an oxygen separator. Oxygen scrubbers are used to wash away alkaline substances that may be trapped in cooled oxygen. An oxygen-hydrogen monitoring instrument is used to monitor the hydrogen concentration in the oxygen at the outlet of an oxygen scrubber. The second temperature instrument is used to monitor the temperature of the oxygen outlet of the alkaline electrolyzer; The second level gauge is used to monitor the liquid level inside the oxygen separator; The second pressure monitoring instrument is used to monitor the pressure inside the oxygen separator.

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