Nitrogen piping system for preventing backflow of hydrogen

Abstract

The application provides a nitrogen pipeline network system for preventing hydrogen backflow, comprising: a nitrogen pipeline for connecting a nitrogen production device and a hydrogen production device; a first valve arranged on the nitrogen pipeline; a second valve arranged on the nitrogen pipeline and located between the first valve and the hydrogen production device; a check valve arranged on the nitrogen pipeline and located between the second valve and the hydrogen production device; and a venting pipeline arranged between the first valve and the second valve, wherein a third valve is arranged on the venting pipeline. The nitrogen pipeline network system for preventing hydrogen backflow provided by the application significantly improves the isolation reliability of the system under abnormal working conditions such as pressure fluctuation and equipment failure through the synergistic effect of multiple valves, and provides a safer solution for hydrogen production.

Description

Technical Field

[0001] This application relates to the field of hydrogen electrolysis technology, and in particular to a nitrogen pipeline system for preventing hydrogen backflow. Background Technology

[0002] Nitrogen pipeline systems are widely used in chemical plants, hydrogen refueling stations, and new energy hydrogen production bases that rely on water electrolysis for hydrogen production (such as PEM water electrolysis or alkaline water electrolysis technology). In these scenarios, water electrolysis hydrogen production systems typically operate at relatively high pressures (e.g., above 1.6 MPa) to improve hydrogen production efficiency and purity. However, hydrogen production systems require frequent inert gas purging, explosion prevention, equipment purging, and protective replacement operations during operation, all of which rely on nitrogen as an inert gas medium. For example, before starting the electrolyzer, nitrogen must be used to replace the air in the system to prevent an explosion caused by the hydrogen-oxygen mixture; during shutdown, nitrogen must be used to isolate the hydrogen system to prevent oxygen or air backflow from triggering a reaction. Furthermore, nitrogen is also used for equipment isolation and leak detection in hydrogen purification, compression, and transportation processes.

[0003] However, traditional nitrogen systems are generally designed for low pressures (e.g., 1.0 MPa), making them unsuitable for the high-pressure operating conditions of hydrogen production systems. This can lead to hydrogen leakage through check valves or backflow into the nitrogen pipeline network due to pressure differentials during start-up and shutdown fluctuations, equipment failures, or pressure imbalances, thereby contaminating the nitrogen system or forming an explosive mixture. Therefore, there is an urgent need for a nitrogen pipeline network system specifically designed for high-pressure hydrogen applications to prevent hydrogen backflow and eliminate safety risks. Utility Model Content

[0004] To address the aforementioned issues, this application provides a nitrogen pipeline system to prevent hydrogen backflow, thereby preventing the reverse flow of hydrogen.

[0005] This application provides a nitrogen pipeline system to prevent hydrogen backflow, including:

[0006] Nitrogen pipeline, used to connect nitrogen generation unit and hydrogen generation unit;

[0007] The first valve is installed on the nitrogen pipeline;

[0008] The second valve is installed on the nitrogen pipeline and is located between the first valve and the hydrogen production device;

[0009] A check valve is installed on the nitrogen pipeline and is located between the second valve and the hydrogen production device;

[0010] A venting pipeline is installed between the first valve and the second valve, and a third valve is installed on the venting pipeline.

[0011] In some embodiments of this application, a pressure regulating device is provided on the nitrogen pipeline. The pressure regulating device is located between the first valve and the nitrogen generating device and is used to regulate the pressure of the nitrogen pipeline so that the pressure of the nitrogen pipeline is greater than the pressure of the hydrogen generating device.

[0012] In some embodiments of this application, the pressure regulating device includes a first manual valve, a regulating valve, a second manual valve, and a pressure sensor arranged sequentially along the airflow direction, wherein the pressure sensor is electrically connected to the regulating valve.

[0013] In some embodiments of this application, the pressure regulating device further includes a safety valve located between the regulating valve and the pressure sensor, and connected to the nitrogen pipeline.

[0014] In some embodiments of this application, the pressure regulating device further includes a double-line valve, the two ends of which are connected to the nitrogen pipeline, one end of which is located between the first manual valve and the nitrogen generator, and the other end of which is located between the second manual valve and the safety valve.

[0015] In some embodiments of this application, the nitrogen pipeline includes a main nitrogen pipe and one or more nitrogen branch pipes connected to the main nitrogen pipe. The pressure regulating device is located on the main nitrogen pipe. The main nitrogen pipe is used to connect to the nitrogen generating device. The nitrogen branch pipes are used to connect to the hydrogen generating device. The first valve, the second valve, the venting pipeline, and the check valve are all disposed on the nitrogen branch pipes.

[0016] In some embodiments of this application, a fourth valve is provided on the nitrogen branch pipe, and the fourth valve is located between the first valve and the pressure regulating device.

[0017] In some embodiments of this application, a hydrogen monitoring pipeline is also included, which is connected to the nitrogen branch pipe and the connection point is located between the second valve and the check valve. A hydrogen monitor is installed in the hydrogen monitoring pipeline.

[0018] In some embodiments of this application, the hydrogen monitor is connected to a controller, which is electrically connected to the first valve, the second valve, and the third valve, respectively.

[0019] And / or, the hydrogen monitoring pipeline is provided with a shut-off valve, a fifth valve and a pressure reducing valve in sequence along the gas flow direction, and the hydrogen monitoring instrument is located at the outlet end of the pressure reducing valve.

[0020] In some embodiments of this application, a figure-eight blind plate is provided between the hydrogen production device and the check valve.

[0021] The nitrogen pipeline system for preventing hydrogen backflow provided in this application connects a nitrogen generator and a hydrogen generator via nitrogen pipelines, forming a nitrogen supply channel. A first valve and a second valve are sequentially installed on the nitrogen pipeline, with the second valve located between the first valve and the hydrogen generator. A venting pipeline connects the first and second valves. A check valve is installed between the second valve and the hydrogen generator to ensure unidirectional nitrogen flow into the hydrogen generator. When the hydrogen generator is operating normally, the first valve, second valve, and check valve are closed to prevent hydrogen from flowing back into the nitrogen pipeline. The third valve is open, connecting to the outside environment. This prevents nitrogen from entering the hydrogen generator, and even if the second valve and check valve leak, hydrogen will be discharged to the outside through the venting pipeline, preventing backflow into the nitrogen pipeline. When the hydrogen generator is shut down or requires maintenance, the first and second valves open simultaneously, and the third valve closes, allowing for purging and protective replacement of the hydrogen generator. The check valve allows unidirectional nitrogen flow into the hydrogen generator, preventing hydrogen from flowing back into the nitrogen pipeline. This application significantly improves the isolation reliability of the system under abnormal operating conditions such as pressure fluctuations and equipment failures through the synergistic effect of multi-stage valves, providing a safer solution for hydrogen production. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0023] Figure 1 This is a schematic diagram of the nitrogen pipeline system for preventing hydrogen backflow provided in this application.

[0024] Explanation of reference numerals in the attached figures:

[0025] 10. Nitrogen pipeline; 11. Main nitrogen pipe; 12. Branch nitrogen pipe; 20. Pressure regulating device; 21. First manual valve; 22. Regulating valve; 23. Second manual valve; 24. Safety valve; 25. Pressure sensor; 26. Double-line valve; 30. First valve; 40. Second valve; 50. Vent pipeline; 51. Third valve; 60. Check valve; 70. Fourth valve; 80. Figure-eight blind flange; 90. Hydrogen monitoring pipeline; 91. Hydrogen monitor; 92. Shut-off valve; 93. Fifth valve; 94. Pressure reducing valve.

[0026] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0027] First, those skilled in the art should understand that these embodiments are merely for explaining the technical principles of this application and are not intended to limit the scope of protection of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0028] Secondly, it should be noted that, in the description of the embodiments of this application, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0029] Nitrogen pipeline systems are widely used in chemical plants, hydrogen refueling stations, and new energy hydrogen production bases that rely on water electrolysis for hydrogen production (such as PEM water electrolysis or alkaline water electrolysis technology). In these scenarios, water electrolysis hydrogen production systems typically operate at relatively high pressures (e.g., above 1.6 MPa) to improve hydrogen production efficiency and purity. However, hydrogen production systems require frequent inert gas purging, explosion prevention, equipment purging, and protective replacement operations during operation, all of which rely on nitrogen as an inert gas medium. For example, before starting the electrolyzer, nitrogen must be used to replace the air in the system to prevent an explosion caused by the hydrogen-oxygen mixture; during shutdown, nitrogen must be used to isolate the hydrogen system to prevent oxygen or air backflow from triggering a reaction. Furthermore, nitrogen is also used for equipment isolation and leak detection in hydrogen purification, compression, and transportation processes.

[0030] In existing technologies, nitrogen pipeline systems typically use simple piping to connect nitrogen and hydrogen production units, with gas isolation achieved through a single check valve or manual valve. During system shutdowns or pressure fluctuations, the check valve may fail to seal properly or malfunction, leading to hydrogen backflow, contaminating the nitrogen pipeline, or even causing an explosion. Therefore, there is an urgent need for a nitrogen pipeline system specifically designed for high-pressure hydrogen applications to prevent hydrogen backflow and eliminate safety risks.

[0031] To address the aforementioned issues, this application provides a nitrogen pipeline system for preventing hydrogen backflow, comprising: a nitrogen pipeline for connecting a nitrogen generator and a hydrogen generator; a first valve disposed on the nitrogen pipeline; a second valve disposed on the nitrogen pipeline and located between the first valve and the hydrogen generator; a check valve disposed on the nitrogen pipeline and located between the second valve and the hydrogen generator; and a vent pipeline disposed between the first valve and the second valve, wherein a third valve is disposed on the vent pipeline.

[0032] The nitrogen pipeline system for preventing hydrogen backflow provided in this application, when the hydrogen production unit is operating normally, has the first valve, second valve, and check valve closed to prevent hydrogen from flowing back into the nitrogen pipeline. The third valve is open, connecting to the outside environment. This prevents nitrogen from entering the hydrogen production unit, and even if the second valve and check valve leak, hydrogen will be discharged to the outside through the venting pipeline, preventing backflow into the nitrogen pipeline. When the hydrogen production unit is shut down or requires maintenance, the first and second valves open simultaneously, and the third valve closes, allowing for purging and protective replacement of the hydrogen production unit. The check valve allows nitrogen to flow unidirectionally into the hydrogen production unit, preventing hydrogen from flowing back into the nitrogen pipeline. This application, through the synergistic effect of multiple valve stages, significantly improves the system's isolation reliability under abnormal operating conditions such as pressure fluctuations and equipment failures, providing a safer solution for hydrogen production.

[0033] To make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent and understandable, 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0034] Please refer to Figure 1 This application provides a nitrogen pipeline system for preventing hydrogen backflow, comprising: a nitrogen pipeline 10 for connecting a nitrogen generator and a hydrogen generator; a first valve 30 disposed on the nitrogen pipeline 10; a second valve 40 disposed on the nitrogen pipeline 10 and located between the first valve 30 and the hydrogen generator; a check valve 60 disposed on the nitrogen pipeline 10 and located between the second valve 40 and the hydrogen generator; and a vent pipeline 50 disposed between the first valve 30 and the second valve 40, wherein a third valve 51 is disposed on the vent pipeline 50.

[0035] The nitrogen pipeline system for preventing hydrogen backflow provided in this application connects a nitrogen generator and a hydrogen generator via a nitrogen pipeline 10, forming a nitrogen supply channel. A first valve 30 and a second valve 40 are sequentially installed on the nitrogen pipeline 10, with the second valve 40 located between the first valve 30 and the hydrogen generator. A venting pipeline 50 is installed between the first valve 30 and the second valve 40. A check valve 60 is installed between the second valve 40 and the hydrogen generator to ensure unidirectional nitrogen flow into the hydrogen generator. When the hydrogen generator is operating normally, the first valve 30, the second valve 40, and the check valve 60 are closed to prevent hydrogen from flowing back into the nitrogen pipeline 10. A third valve 51 is open, connecting to the outside environment. This prevents nitrogen from entering the hydrogen generator, and even if the second valve 40 and the check valve 60 leak, hydrogen will be discharged to the outside through the venting pipeline and will not flow back into the nitrogen pipeline 10. When the hydrogen production unit is shut down or requires maintenance, the first valve 30 and the second valve 40 open simultaneously, while the third valve 51 closes, to purge and protect the hydrogen production unit. The check valve 60 allows nitrogen to flow unidirectionally into the hydrogen production unit, preventing hydrogen from flowing back into the nitrogen pipeline 10. This application, through the synergistic effect of multiple valve stages, significantly improves the system's isolation reliability under abnormal operating conditions such as pressure fluctuations and equipment failures, providing a safer solution for hydrogen production.

[0036] It is understandable that the first valve 30, the second valve 40 and the third valve 51 can be pneumatic ball valves, electric ball valves, etc., and this application does not limit them.

[0037] In related technologies, traditional nitrogen systems are generally designed for lower pressures (e.g., 1.0 MPa), while water electrolysis hydrogen production systems typically operate at higher pressures (e.g., above 1.6 MPa). This can lead to hydrogen leaking through check valve 60 or backflowing into the nitrogen pipeline due to pressure differential during start-up and shutdown fluctuations, equipment failures, or pressure imbalances.

[0038] To address the above problems, in some embodiments of this application, see [reference needed]. Figure 1 A pressure regulating device 20 is installed on the nitrogen pipeline 10. The pressure regulating device 20 is located between the first valve 30 and the nitrogen generating device and is used to regulate the pressure of the nitrogen pipeline 10 so that the pressure of the nitrogen pipeline 10 is greater than the pressure of the hydrogen generating device.

[0039] The pressure regulating device 20 can adjust the pressure in the nitrogen pipeline 10 to ensure that the pressure in the nitrogen pipeline 10 is greater than the pressure in the hydrogen production unit, thus creating positive pressure. The dynamic pressure compensation function of the pressure regulating device 20 further solves the problem of gas cross-contamination caused by pressure imbalance.

[0040] Understandably, the pressure in the nitrogen pipeline 10 can be adjusted to 1.7 MPa, 1.8 MPa, etc., by means of the pressure regulator 20, which is greater than the pressure of the hydrogen production device. The specific pressure value is not limited in this application.

[0041] In some embodiments of this application, see Figure 1 The pressure regulating device 20 includes a first manual valve 21, a regulating valve 22, a second manual valve 23 and a pressure sensor 25 arranged sequentially along the airflow direction. The pressure sensor 25 is electrically connected to the regulating valve 22.

[0042] The first manual valve 21 and the second manual valve 23 are respectively located at the front and rear ends of the regulating valve 22 and the pressure sensor 25, and are used to manually intervene in the opening and closing of the nitrogen pipeline 10 and the flow rate regulation. The pressure sensor 25 monitors the pressure of the nitrogen pipeline 10 in real time and transmits the signal to the regulating valve 22. The regulating valve 22 adjusts the nitrogen flow rate according to a preset threshold to maintain a stable pressure in the nitrogen pipeline 10. When the pressure rises, the valve of the regulating valve 22 closes slightly; when the pressure drops, the valve of the regulating valve 22 opens wider. The linkage between the pressure sensor 25 and the regulating valve 22 ensures that the pressure in the nitrogen pipeline 10 is always higher than the pressure of the hydrogen production unit, maintaining a positive pressure state to prevent hydrogen backflow.

[0043] In some embodiments of this application, the pressure regulating device 20 further includes a safety valve 24, which is located between the regulating valve 22 and the pressure sensor 25 and is connected to the nitrogen pipeline 10.

[0044] Safety valve 24 is normally closed. It automatically opens when the pressure of the medium in the pipeline rises above a specified value, preventing the pressure of the medium in the pipeline from exceeding the specified value by discharging the medium outside the system. When the pressure returns to normal, the valve automatically closes and prevents the medium from continuing to flow out, thereby maintaining the pressure stability of the nitrogen pipeline 10. The redundant design of safety valve 24 provides additional protection under extreme operating conditions, avoiding pipeline overpressure damage and improving the system's adaptability to complex environments.

[0045] In some embodiments of this application, see Figure 1 The pressure regulating device 20 also includes a double-line valve 26, with both ends of the double-line valve 26 connected to the nitrogen pipeline 10. One end is located between the first manual valve 21 and the nitrogen generator, and the other end is located between the second manual valve 23 and the safety valve 24.

[0046] When the system is operating normally, the secondary valve 26 remains closed. If any of the first manual valve 21, the second manual valve 23, or the regulating valve 22 malfunctions, the secondary valve 26 can be manually opened to maintain the nitrogen supply, enabling online maintenance of the first manual valve 21, the second manual valve 23, or the regulating valve 22.

[0047] In some embodiments of this application, the first manual valve 21, the second manual valve 23, and the double-line valve 26 are all gate valves. It is understood that the first manual valve 21, the second manual valve 23, and the double-line valve 26 may also be manual ball valves or other types of valves.

[0048] In some embodiments of this application, see Figure 1 The nitrogen pipeline 10 includes a main nitrogen pipe 11 and one or more nitrogen branch pipes 12 connected to the main nitrogen pipe 11. The pressure regulating device 20 is located on the main nitrogen pipe 11. The main nitrogen pipe 11 is used to connect to the nitrogen generating device, and the nitrogen branch pipes 12 are used to connect to the hydrogen generating device. The first valve 30, the second valve 40, the vent pipe 50 and the check valve 60 are all installed on the nitrogen branch pipes 12.

[0049] In scenarios with multiple hydrogen production units, existing systems typically use a unified nitrogen supply pipeline, which cannot achieve zonal isolation and independent control, increasing the risk of cross-contamination. This application addresses this by setting up a main nitrogen pipe 11 and multiple nitrogen branch pipes 12, forming multiple independent nitrogen supply branches. A single nitrogen production unit can simultaneously supply nitrogen to multiple hydrogen production units, and the multiple nitrogen branch pipes 12 are isolated from each other and can be controlled independently. Even if one hydrogen production unit malfunctions, it will not affect other hydrogen production units, improving safety performance.

[0050] In some embodiments of this application, see Figure 1 A fourth valve 70 is provided on the nitrogen branch pipe 12, and the fourth valve 70 is located between the first valve 30 and the pressure regulating device 20.

[0051] The fourth valve 70 is normally open. When the first valve 30 fails, the fourth valve 70 can be closed to disconnect the nitrogen branch pipe 12 from the nitrogen generator, allowing the first valve 30 to be inspected and repaired. This further solves the problem of physical isolation between the nitrogen generator and the hydrogen generator. The independent control function of the fourth valve 70 provides an additional isolation measure when the first valve 30 fails.

[0052] In some embodiments of this application, the fourth valve 70 is a gate valve, while in other embodiments, the fourth valve 70 may also be a ball valve or the like. This application does not impose any limitations.

[0053] In some embodiments of this application, see Figure 1 Each nitrogen branch pipe 12 is equipped with a hydrogen monitoring pipeline 90. The hydrogen monitoring pipeline 90 is connected to the nitrogen branch pipe 12, and the connection point is located between the second valve 40 and the check valve 60. A hydrogen monitor 91 is installed in the hydrogen monitoring pipeline 90.

[0054] If the check valve 60 is properly sealed, the hydrogen monitor 91 will not detect hydrogen. If the check valve 60 fails to seal, hydrogen will pass through the check valve 60 and enter the hydrogen monitoring pipeline 90, where it will be detected by the hydrogen monitor 91, thus enabling the monitoring of hydrogen backflow. When the hydrogen monitor 91 detects hydrogen, the operator can close the first valve 30 and the second valve 40 to prevent hydrogen from flowing back into the nitrogen main pipe 11, and simultaneously open the third valve 51 to purge the hydrogen from the nitrogen branch pipe 12.

[0055] In some embodiments of this application, the hydrogen monitor 91 is connected to a controller, which is electrically connected to the first valve 30, the second valve 40 and the third valve 51 respectively.

[0056] Existing systems rely on manual operation of valves or monitoring equipment, resulting in slow response times and susceptibility to safety hazards due to human error. This application addresses this by using a hydrogen monitor 91 to send detected hydrogen concentration data to a controller. The controller then controls the opening and closing of the first valve 30, the second valve 40, and the third valve 51 based on this data. When the hydrogen concentration exceeds a set threshold, the controller automatically closes the first valve 30 and the second valve 40 to prevent hydrogen backflow into the nitrogen main pipe 11, and the third valve 51 automatically opens to vent the hydrogen from the nitrogen branch pipe 12. Through the coordinated control of the hydrogen monitor 91 and the first valve 30, the second valve 40, and the third valve 51, automated monitoring and handling of hydrogen backflow can be achieved, eliminating the need for manual operation, improving the timeliness of accident response, and reducing safety risks.

[0057] In some embodiments of this application, see Figure 1 The hydrogen monitoring pipeline 90 is provided with a shut-off valve 92, a fifth valve 93 and a pressure reducing valve 94 in sequence along the airflow direction, and the hydrogen monitor 91 is located at the outlet of the pressure reducing valve 94.

[0058] The shut-off valve 92 is used for manual shut-off and is normally open. In case of emergency, operators can manually disconnect the hydrogen monitoring pipeline 90 from the nitrogen branch pipe 12. The fifth valve 93 is for remote control, allowing operators to remotely control its opening and closing status for ease of operation. It is understood that the fifth valve 93 can be a pneumatic or electric valve; this application does not impose any limitation. The pressure reducing valve 94 is used to reduce the pressure of the gas in the pipeline, facilitating gas detection by the hydrogen monitor 91. The combination of the shut-off valve 92, the fifth valve 93, and the pressure reducing valve 94 further addresses the complexity of hydrogen monitoring operation. The combination of manual and remote control enhances the flexibility of the hydrogen monitoring pipeline 90, while the pressure reducing valve 94 ensures that the hydrogen monitor 91 operates within a safe pressure range, extending the equipment's lifespan.

[0059] In some embodiments of this application, a figure-eight blind plate 80 is provided between the hydrogen production device and the check valve 60.

[0060] Specifically, the figure-eight blind flange 80 is normally open. When maintenance is required, or when the first valve 30 or the second valve 40 fails due to a malfunction, the figure-eight blind flange 80 can be switched to the closed state, cutting off the physical connection between the hydrogen generator and the nitrogen pipeline 10. This ensures complete isolation of the medium during maintenance operations, further eliminating the risk of hydrogen contamination of the nitrogen pipeline network.

[0061] In some embodiments of this application, the hydrogen production device is an electrolytic hydrogen production device.

[0062] Understandably, this application can also be applied to other types of flammable and explosive gas preparation systems to prevent backflow of flammable and explosive gases.

[0063] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0064] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0065] Finally, it should be noted that other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and alterations may be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A nitrogen pipeline system for preventing hydrogen backflow, characterized in that, include: Nitrogen pipeline, used to connect nitrogen generation unit and hydrogen generation unit; The first valve is installed on the nitrogen pipeline; The second valve is installed on the nitrogen pipeline and is located between the first valve and the hydrogen production device; A check valve is installed on the nitrogen pipeline and is located between the second valve and the hydrogen production device; A venting pipeline is installed between the first valve and the second valve, and a third valve is installed on the venting pipeline.

2. The nitrogen pipeline system for preventing hydrogen backflow according to claim 1, characterized in that, A pressure regulating device is installed on the nitrogen pipeline. The pressure regulating device is located between the first valve and the nitrogen generating device and is used to regulate the pressure of the nitrogen pipeline so that the pressure of the nitrogen pipeline is greater than the pressure of the hydrogen generating device.

3. The nitrogen pipeline system for preventing hydrogen backflow according to claim 2, characterized in that, The pressure regulating device includes a first manual valve, a regulating valve, a second manual valve, and a pressure sensor arranged sequentially along the airflow direction, and the pressure sensor is electrically connected to the regulating valve.

4. The nitrogen pipeline system for preventing hydrogen backflow according to claim 3, characterized in that, The pressure regulating device also includes a safety valve, which is located between the regulating valve and the pressure sensor and is connected to the nitrogen pipeline.

5. The nitrogen pipeline system for preventing hydrogen backflow according to claim 4, characterized in that, The pressure regulating device also includes a double-line valve, the two ends of which are connected to the nitrogen pipeline, one end of which is located between the first manual valve and the nitrogen generator, and the other end of which is located between the second manual valve and the safety valve.

6. The nitrogen pipeline system for preventing hydrogen backflow according to any one of claims 2-5, characterized in that, The nitrogen pipeline includes a main nitrogen pipe and one or more nitrogen branch pipes connected to the main nitrogen pipe. The pressure regulating device is located on the main nitrogen pipe. The main nitrogen pipe is used to connect to the nitrogen generating device. The nitrogen branch pipes are used to connect to the hydrogen generating device. The first valve, the second valve, the venting pipeline, and the check valve are all located on the nitrogen branch pipes.

7. The nitrogen pipeline system for preventing hydrogen backflow according to claim 6, characterized in that, A fourth valve is provided on the nitrogen branch pipe, and the fourth valve is located between the first valve and the pressure regulating device.

8. The nitrogen pipeline system for preventing hydrogen backflow according to claim 6, characterized in that, It also includes a hydrogen monitoring pipeline, which is connected to the nitrogen branch pipe, and the connection point is located between the second valve and the check valve. A hydrogen monitor is installed in the hydrogen monitoring pipeline.

9. The nitrogen pipeline system for preventing hydrogen backflow according to claim 8, characterized in that, The hydrogen monitor is connected to a controller, which is electrically connected to the first valve, the second valve, and the third valve respectively. And / or, the hydrogen monitoring pipeline is provided with a shut-off valve, a fifth valve and a pressure reducing valve in sequence along the gas flow direction, and the hydrogen monitoring instrument is located at the outlet end of the pressure reducing valve.

10. The nitrogen pipeline system for preventing hydrogen backflow according to claim 1, characterized in that, A figure-eight blind flange is installed between the hydrogen production device and the check valve.

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