CN216979019U - Hydrogen dilution pressure regulating system and hydrogen fuel cell test bench - Google Patents

Abstract

The utility model discloses a hydrogen dilution pressure regulating system and a hydrogen fuel cell test bench, and belongs to the technical field of hydrogen fuel cells. The dilution pressure regulating system comprises a buffer gas tank, a hydrogen input pipeline, a nitrogen input pipeline and a pressure regulating assembly, wherein the hydrogen input pipeline is communicated with an air inlet pipeline of the buffer gas tank, and a first flow controller and a first hydrogen product concentration detector are arranged on the hydrogen input pipeline; the nitrogen input pipeline is communicated with an air inlet pipeline of the buffer air tank and is provided with a second flow controller; the pressure regulating assembly is arranged on the exhaust pipeline of the buffer gas tank, so that the mixed gas in the buffer gas tank is exhausted from the exhaust pipeline in a state of being greater than the standard atmospheric pressure. Mixing hydrogen until the volume concentration is less than the explosion limit, and the chemical property of the nitrogen is stable, so that the explosion risk of tail exhaust gas is reduced; the mixed gas is subjected to pressure regulation, so that the mixed gas is greater than the standard atmospheric pressure and is discharged, the atmosphere is prevented from flowing backwards into a discharge passage of the mixed gas, and the mixed gas is conveniently and smoothly discharged.

Description

Hydrogen dilution pressure regulating system and hydrogen fuel cell test bench

Technical Field

The utility model relates to the technical field of hydrogen fuel cells, in particular to a hydrogen dilution pressure regulating system and a hydrogen fuel cell test bench.

Background

Hydrogen energy is considered to be the best quality clean, efficient energy source in the future and is receiving wide attention worldwide. The development of hydrogen energy enters a rapid development stage, the power of the hydrogen fuel cell is gradually increased, and the test requirement on the hydrogen fuel cell is continuously increased.

Because anode hydrogen in the high-power fuel cell can not be completely consumed, redundant part of hydrogen is discharged to the air in the form of nearly pure hydrogen, the explosion limit of the hydrogen concentration is 4-75.6% of the volume concentration, and explosion and even explosion are very likely to occur when exposed fire and electrostatic sparks happen, so that the personal safety is threatened.

The hydrogen discharged from the tail of the anode of the current hydrogen fuel cell is usually diluted by introducing air, but the gas components and the content in the air cannot be clearly and quickly obtained, and after the hydrogen components mixed in the air are mixed with the hydrogen in the gas discharged from the tail of the anode, the risk of improving the hydrogen concentration is very easily caused, and the safety of the tail gas is reduced; moreover, the oxygen activity in the air is high and unstable, and when the hydrogen concentration is in the boundary of the explosion range, the possibility of explosion and the power of explosion are increased, and the danger is high because the hydrogen is directly diluted by the air. And because the density of the hydrogen is far less than that of the air, the air is easy to partially block the exhaust channel of the hydrogen in the process of discharging the hydrogen, so that the discharging is not smooth.

Therefore, it is desirable to provide a hydrogen dilution pressure regulating system and a hydrogen fuel cell test bench to solve the above problems.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a hydrogen dilution pressure regulating system and a hydrogen fuel cell test bench, which can reduce the volume concentration of hydrogen in tail exhaust gas to a safe range and ensure the smooth flowing and safe discharge of the diluted and mixed hydrogen.

In order to realize the purpose, the following technical scheme is provided:

a hydrogen dilution pressure regulating system comprising:

a buffer gas tank is arranged at the bottom of the air tank,

one end of the hydrogen input pipeline can be communicated with a hydrogen-containing gas source, the other end of the hydrogen input pipeline is communicated with the gas inlet pipeline of the buffer gas tank, and a first flow controller and a first hydrogen product concentration detector are arranged on the hydrogen input pipeline;

one end of the nitrogen input pipeline can be communicated with a nitrogen source, the other end of the nitrogen input pipeline is communicated with an air inlet pipeline of the buffer air tank, and a second flow controller is arranged on the nitrogen input pipeline;

and the pressure regulating assembly is arranged on the exhaust pipeline of the buffer gas tank and used for enabling the mixed gas in the buffer gas tank to be exhausted from the exhaust pipeline in a state greater than the standard atmospheric pressure.

As an alternative to the hydrogen dilution pressure regulating system, a three-way valve is further included, the three-way valve including two inlets and one outlet; the hydrogen input pipeline is communicated with one inlet of the three-way valve; the nitrogen input pipeline is communicated with the other inlet of the three-way valve; and an air inlet pipeline of the buffer air tank is communicated with an outlet of the three-way valve.

As an alternative of the hydrogen dilution pressure regulating system, a second hydrogen volume concentration detector is arranged on the exhaust pipeline and is in communication connection with the second flow controller.

As an alternative of a hydrogen dilution pressure regulating system, the pressure regulating assembly comprises a pressure detector and a fan, the pressure detector and the fan are arranged on the exhaust pipeline, the pressure detector is in communication connection with the fan, and the rotating speed of the fan can be regulated.

As an alternative of the hydrogen dilution pressure regulating system, a pressure regulating valve is arranged on the exhaust pipeline, and the mixed gas subjected to pressure regulation by the pressure regulating assembly is discharged through the pressure regulating valve.

As an alternative of the hydrogen dilution pressure regulating system, a flame arrester is arranged on the exhaust pipeline.

As an alternative of the hydrogen dilution pressure regulating system, the hydrogen dilution pressure regulating system further comprises a first one-way valve, and the first one-way valve is arranged on the hydrogen input pipeline.

As an alternative of the hydrogen dilution pressure regulating system, the hydrogen dilution pressure regulating system further comprises a second one-way valve, and the second one-way valve is arranged on the exhaust pipeline.

The hydrogen dilution pressure regulating system further comprises a dehumidifier, wherein the dehumidifier is arranged on the hydrogen input pipeline and used for removing moisture in the hydrogen input pipeline.

A hydrogen fuel cell test bench comprises the hydrogen dilution pressure regulating system, and an anode tail outlet of a hydrogen fuel cell is communicated with a hydrogen input pipeline.

Compared with the prior art, the utility model has the beneficial effects that:

the hydrogen dilution pressure regulating system provided by the utility model regulates the flow ratio of the first flow controller and the second flow controller according to the detection value of the first hydrogen volume concentration detector, so that the volume concentration of hydrogen in the mixed gas is smaller than the explosion limit after the hydrogen and the nitrogen are mixed; and because the nitrogen is more stable, the explosion risk of tail gas is further reduced; the pressure of the mixed gas to be discharged is adjusted, so that the pressure value of the mixed gas is greater than the standard atmospheric pressure and the mixed gas is discharged.

The hydrogen fuel cell test bench provided by the utility model adjusts the flow of the first flow controller and the second flow controller, so that the volume concentration of hydrogen is lower than the explosion limit; set up the pressure regulating subassembly that can adjust the gaseous pressure of mist exhaust size on the blast pipe way, make the mist discharge into the atmosphere with the state that is greater than standard atmospheric pressure, the mist does not take place to block up or backward flow, guarantees that hydrogen can smoothly and safely be discharged.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a hydrogen dilution pressure regulating system in an embodiment of the present invention.

Reference numerals:

1. a three-way valve; 2. a hydrogen input line; 3. a nitrogen input pipeline; 4. a buffer gas tank; 5. an exhaust line;

21. a first flow controller; 22. a first hydrogen gas volume concentration detector; 23. a steam-water separator; 24. a drain valve; 25. a drain pipe; 26. a first check valve;

31. a second flow controller;

51. a pressure detector; 52. a second hydrogen gas volume concentration detector; 53. a flame arrestor; 54. a pressure regulating valve; 55. a second one-way valve; 56. a fan.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings or orientations or positional relationships that are usually placed when the products of the present invention are used, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; either mechanically or electrically. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

The anode terminal in the existing hydrogen fuel cell can discharge hydrogen at regular time, especially in the hydrogen fuel cell with high power, the hydrogen can not be completely consumed. The explosion limit of the hydrogen concentration is 4-75.6% volume concentration, and the redundant hydrogen is discharged into the air in the form of nearly pure hydrogen, so that detonation and even explosion are very likely to occur when the ignition material is met, and the production and life are threatened.

In order to reduce the volume concentration of hydrogen in the hydrogen fuel cell to a safe range and ensure smooth flow and safe discharge of hydrogen, the present embodiment provides a hydrogen dilution pressure regulating system, and the details of the present embodiment are described in detail below with reference to fig. 1.

As shown in fig. 1, the hydrogen dilution pressure regulating system includes a three-way valve 1, a hydrogen input pipeline 2, a nitrogen input pipeline 3, a buffer tank 4, an exhaust pipeline 5, and a central control module. The three-way valve 1 is provided with two inlets and one outlet, and a hydrogen input line 2 is communicated with one inlet of the three-way valve 1, and a nitrogen input line 3 is communicated with the other inlet of the three-way valve 1. A first flow controller 21 and a first hydrogen gas concentration detector 22 are arranged on the hydrogen gas input pipeline 2, and a second flow controller 31 is arranged on the nitrogen gas input pipeline 3; the exhaust pipeline 5 is provided with a pressure regulating assembly for regulating the pressure of the mixed gas discharged from the buffer gas tank 4. The first flow controller 21, the first hydrogen volumetric concentration detector 22 and the second flow controller 31 are in communication with the central control module. The central control module can record and analyze the flow values and the concentration detection values of the first flow controller 21, the first hydrogen volume concentration detector 22 and the second flow controller 31, and coordinately control the flow proportions of the first flow controller 21 and the second flow controller 31 according to the detection value of the first hydrogen volume concentration detector 22, so that the volume concentration of the hydrogen entering the buffer gas tank 4 is lower than the explosion limit. The flow rate detected and controlled by the flow rate controller in this embodiment is a volume flow rate.

The nitrogen is the gas with the highest proportion in the earth atmosphere, and accounts for 78.3 percent, and the nitrogen is not combustible or combustion-supporting. And nitrogen is adopted to dilute hydrogen, so that the explosion risk of tail exhaust gas is further reduced.

The specific dilution pressure regulating method comprises the following steps: step S1: mixing tail exhaust gas with nitrogen, controlling the flow of the nitrogen mixed with the hydrogen in the tail exhaust gas according to the flow of the hydrogen in the tail exhaust gas, and mixing the tail exhaust gas with the nitrogen to ensure that the volume concentration of the hydrogen in the mixed gas is lower than the explosion limit; step S2: and adjusting the pressure of the mixed gas to make the pressure of the mixed gas be greater than the standard atmospheric pressure and discharging the mixed gas into the atmosphere.

According to the flow of the hydrogen in the tail exhaust gas, the flow of the nitrogen mixed with the tail exhaust gas is controlled, the volume concentration of the hydrogen mixed with the tail exhaust gas is smaller than the explosion limit, the hydrogen in the discharged mixed gas is smaller than the explosion limit range, the discharge capacity of the nitrogen is changed along with the change of the flow of the hydrogen in the tail exhaust gas, the waste of the nitrogen is avoided, and the cost is saved. And the nitrogen has stable chemical property and low activity, and is diluted by adopting the nitrogen, so that the safety of the tail exhaust mixed gas is further improved. The pressure of the mixed gas to be discharged is adjusted, so that the pressure value of the mixed gas is greater than the standard atmospheric pressure and the mixed gas is discharged, on one hand, the pressure difference exists between the pressure value of the mixed gas and the standard atmospheric pressure, so that the atmosphere cannot flow back into a discharge channel of the mixed gas, the discharge channel cannot be partially blocked due to the density difference between hydrogen and air, and the mixed gas is conveniently and smoothly discharged; on the other hand, the quick diffusion of mist of being convenient for avoids atmospheric pressure to compress the mist, leads to the volume concentration of hydrogen in the nitrogen-hydrogen gas mixture to improve, faces the explosion risk.

And in the process of discharging the mixed gas, detecting the volume concentration of the hydrogen in the mixed gas in real time, calculating the difference between the detection value of the first hydrogen volume concentration detector 22 and a first preset value, and adjusting the flow of the nitrogen according to the difference, wherein the first preset value is less than or equal to the explosion limit of the hydrogen. The national emission standard for hydrogen is that the safe volume concentration of hydrogen is 25% of the lower explosion limit (i.e. the national volume concentration of hydrogen safe emission is 1%). The first preset value may be 1%.

The concentration of hydrogen gas discharged was controlled to 10% of the lower explosion limit thereof in this example, that is, the volume concentration of discharged hydrogen gas was 0.4%. That is, the first preset value in the present embodiment is 0.4%, and illustratively, when the hydrogen gas volume concentration in the mixed gas is greater than 0.4%, the flow rate of the nitrogen gas flow controller increases until the hydrogen gas volume concentration in the mixed gas does not exceed 0.4%, which is lower and higher in safety in the present embodiment.

In other application scenarios, the first preset value may also be 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.3%, 0.2%, etc., and the flow rate of the nitrogen gas is adjusted accordingly.

In some application scenarios, when the external temperature is lower than the temperature of the mixed gas, the cooled volume shrinks just after the mixed gas is discharged, so that the volume concentration of the diluted hydrogen increases, and the risk of explosion exists. The mixed gas is compressed, and the influence of temperature is reduced.

The anode tail exhaust gas also contains moisture, so that the flow measurement accuracy of the flow controller is influenced, and the moisture flow is easily calculated as the hydrogen flow. Therefore, before step S1, a step of removing moisture in the tail gas is further included. Specifically, the steam-water separator 23 may be used to dehumidify the anode tail gas, so as to improve the control accuracy of the flow controller and reduce the control error.

In step S1, the flow rate of hydrogen in the tail gas is determined from the detected value of the volume concentration of hydrogen in the tail gas and the flow rate of the tail gas. Because the tail exhaust gas contains water, the actual flow of the hydrogen is the product of the volume concentration detection value of the hydrogen in the tail exhaust gas and the flow of the tail exhaust gas.

In step S2, the pressure difference between the pressure of the mixed gas and the standard atmospheric pressure is adjusted to be not less than the second preset value. In the present embodiment, the second preset value is 10 kpa. The fire arrester 53 is arranged on the exhaust pipeline 5 of the tail exhaust gas, and the fire arrester 53 generates certain resistance to the exhaust of the mixed gas, so that the exhaust pressure of the mixed gas is not less than the sum of the standard atmosphere and 10 kpa. In other embodiments, the pressure difference between the mixed gas pressure and the standard atmospheric pressure can be adjusted according to the resistance generated by other types of accessories. The second preset value may also be 11kpa, 20kpa, 30kpa, 40kpa, etc., without being limited thereto.

Specifically, the hydrogen input line 2 communicates with an anode exhaust port of the fuel cell, and introduces exhaust gas into the hydrogen input line 2, and the first flow controller 21 is configured to detect and control a flow rate through which the exhaust gas flows.

When the concentrations of both hydrogen and nitrogen are known, the concentration of hydrogen can be accurately diluted by adjusting the flow rate of the first flow controller 21 and the flow rate of the second flow controller 31.

When the concentration of the hydrogen is unknown and the concentration of the nitrogen is known, the tail gas contains hydrogen and moisture, so in order to eliminate the influence of the moisture flow on the control of the detected hydrogen flow and improve the detection precision and accuracy of the first flow controller 21, a steam-water separator 23 and a first hydrogen product concentration detector 22 are arranged on the hydrogen input pipeline 2, the steam-water separator 23 is used for dehumidifying the tail gas, the first hydrogen product concentration detector 22 is used for detecting the volume concentration detection value of the dehumidified hydrogen, the actual hydrogen flow is the product of the concentration detection value of the first hydrogen product concentration detector 22 and the detection flow value of the first flow controller 21, and the central control module can perform proportional control according to the actual hydrogen flow and the actual nitrogen flow detected by the second flow controller 31. In this process, the flow rate of the hydrogen gas can be obtained by monitoring the first hydrogen gas volume concentration detector 22 and the first flow rate controller 21.

The flow of the first flow controller 21 and the flow of the second flow controller 31 are adjusted, so that the hydrogen in the nitrogen and the tail exhaust gas are converged in the three-way valve 1 and simultaneously enter the buffer gas tank 4, and the tail exhaust gas and the nitrogen are fully mixed after the nitrogen and the hydrogen are converged by the three-way valve 1, so that the local concentration of the hydrogen is prevented from exceeding the explosion limit. The steam-water separator 23 mainly utilizes the difference of specific gravity of gas and liquid in the fluid turning process, so that the liquid sinks to be separated from the gas. The primary fluid can be diverted by baffles or by centrifugal separation by high velocity gas streams which throw the liquid against the walls of the vessel where it loses kinetic energy and is separated from the gas. Before hydrogen enters the three-way valve 1, the hydrogen keeps dry, and the corrosion of water vapor to the three-way valve 1 and other parts is avoided.

In the use, when the pressure of nitrogen gas is greater than the pressure of hydrogen, when two kinds of gas joined in three-way valve 1, caused the circulation of hydrogen not smooth easily, through setting up the pressure regulating subassembly at exhaust pipe 5, bled hydrogen and nitrogen gas simultaneously, alleviateed the hindrance of nitrogen gas to hydrogen, made hydrogen and nitrogen gas all smoothly discharge from exhaust pipe 5.

As shown in fig. 1, a second hydrogen gas volume concentration detector 52 is provided on the exhaust line 5 of the buffer tank 4, and the second hydrogen gas volume concentration detector 52 is connected in communication with the second flow rate controller 31. The second hydrogen gas volume concentration detector 52 is used for correcting the flow rate of the second flow controller 31, and when the detection value of the second hydrogen gas volume concentration detector 52 is greater than 0.4%, the second hydrogen gas volume concentration detector 52 can control the second flow controller 31 to increase the flow rate by signal communication so as to reduce the volume concentration of the hydrogen gas in the mixed gas.

As shown in fig. 1, the pressure regulating assembly includes a pressure detector 51 and a fan 56, the pressure detector 51 and the fan 56 are disposed on the exhaust pipe 5, and the pressure detector 51 is in communication connection with the fan 56 and can regulate the rotation speed of the fan 56. When the pressure detector 51 detects whether the air pressure of the mixed gas just discharged from the buffer tank 4 is smaller than the standard atmospheric pressure, and when the air pressure of the mixed gas is smaller than the standard atmospheric pressure, the pressure detector 51 starts the fan 56 to rotate after signal communication, and can adjust the rotating speed of the fan 56 to increase the air pressure of the mixed gas. The pressure detector 51 in this embodiment is a pressure gauge, the blower 56 discharges the mixed gas in the direction of the atmosphere, the rotation speed of the blower 56 is adjusted according to the pressure detected by the pressure gauge in the process, and the mixed gas is maintained in a state greater than the standard atmospheric pressure under the condition that the nitrogen and the anode tail exhaust gas are ensured not to enter the buffer gas tank 4.

Further, the tail end of the exhaust pipeline 5 is provided with a flame arrester 53, the flame arrester 53 is also called a fire arrester and a pipeline flame arrester, and is used for preventing external flame from entering equipment and pipelines which are filled with inflammable and explosive gas or preventing flame from spreading between the equipment and the pipelines, so that the safety of tail-exhausted hydrogen is improved. The pressure regulating assembly makes the pressure difference between the mixed gas in the exhaust pipeline 5 and the standard atmosphere not less than 10kpa, and the mixed gas is exhausted from the flame arrester 53. In other embodiments, the pressure of the mixed gas in the exhaust line 5 is higher than the standard atmosphere by 10kpa, 12kpa, 14kpa, 16kpa, 18kpa, etc., depending on the type of flame arrester 53, which is not limited herein.

A pressure regulating valve 54 is provided in the hydrogen gas supply line 2, and the mixed gas whose pressure has been regulated by a fan 56 is discharged through the pressure regulating valve 54. When the pressure difference between the mixed gas and the standard atmospheric pressure is not less than 10kpa, the pressure regulating valve 54 is opened, and finally the pressure difference between the mixed gas and the atmosphere is ensured to be less than 10kpa, and the volume concentration of the hydrogen is not more than 0.4%.

In some application scenarios, the hydrogen input pipeline 2 is provided with a first one-way valve 26 and a dehumidifier 23, and the dehumidifier 23 in the present embodiment is a steam-water separator for removing water from the hydrogen in the hydrogen input pipeline 2. The exhaust line 5 is provided with a second check valve 55. Specifically, the first check valve 26 is located between the steam-water separator 23 and the first hydrogen volumetric concentration detector 22, preventing the hydrogen gas from flowing back. The steam-water separator 23 drains the water through a drain valve 24 into a drain 25. Specifically, the second check valve 55 is located between the second hydrogen volumetric concentration detector 52 and the pressure regulating valve 54, and functions to prevent the mixture gas from flowing back.

This embodiment still provides a hydrogen fuel cell test bench, dilutes the pressure regulating system including foretell hydrogen, with hydrogen fuel cell's positive pole tail mouth and hydrogen input pipeline 2 intercommunication, is convenient for with the safe effectual discharge of hydrogen in the positive pole tail mouth of fuel cell.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the utility model. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (10)

1. A hydrogen dilution pressure regulating system, comprising:

a buffer gas tank (4),

one end of the hydrogen input pipeline (2) can be communicated with a hydrogen-containing gas source, the other end of the hydrogen input pipeline is communicated with an air inlet pipeline of the buffer gas tank (4), and a first flow controller (21) and a first hydrogen volume concentration detector (22) are arranged on the hydrogen input pipeline (2);

one end of the nitrogen input pipeline (3) can be communicated with a nitrogen source, the other end of the nitrogen input pipeline is communicated with an air inlet pipeline of the buffer air tank (4), and a second flow controller (31) is arranged on the nitrogen input pipeline (3);

the pressure regulating assembly is arranged on an exhaust pipeline (5) of the buffer gas tank (4) and used for enabling the mixed gas in the buffer gas tank (4) to be exhausted from the exhaust pipeline (5) in a state larger than the standard atmospheric pressure.

2. The hydrogen dilution pressure regulating system according to claim 1, further comprising a three-way valve (1), the three-way valve (1) comprising two inlets and one outlet; the hydrogen input pipeline (2) is communicated with one inlet of the three-way valve (1); the nitrogen input pipeline (3) is communicated with the other inlet of the three-way valve (1); and an air inlet pipeline of the buffer air tank (4) is communicated with an outlet of the three-way valve (1).

3. The hydrogen dilution pressure regulating system according to claim 1, wherein a second hydrogen volume concentration detector (52) is disposed on the exhaust pipe (5), and the second hydrogen volume concentration detector (52) is in communication connection with the second flow controller (31).

4. The hydrogen dilution pressure regulating system according to claim 1, wherein the pressure regulating assembly comprises a pressure detector (51) and a fan (56), the pressure detector (51) and the fan (56) are arranged on the exhaust pipeline (5), and the pressure detector (51) is in communication connection with the fan (56) and can regulate the rotating speed of the fan (56).

5. The hydrogen dilution pressure regulating system according to claim 1 or 4, wherein the exhaust line (5) is provided with a pressure regulating valve (54), and the mixed gas pressure-regulated by the pressure regulating assembly is discharged through the pressure regulating valve (54).

6. Hydrogen dilution pressure regulating system according to claim 1, wherein a flame arrester (53) is provided on the exhaust line (5).

7. The hydrogen dilution pressure regulating system according to claim 1, further comprising a first check valve (26), the first check valve (26) being disposed on the hydrogen input line (2).

8. Hydrogen dilution pressure regulating system according to claim 1, further comprising a second one-way valve (55), the second one-way valve (55) being arranged on the vent line (5).

9. The hydrogen dilution pressure regulating system according to claim 1, further comprising a dehumidifier (23), wherein the dehumidifier (23) is provided on the hydrogen input line (2) for removing moisture from the hydrogen input line (2).

10. A hydrogen fuel cell test rig comprising a hydrogen dilution pressure regulation system according to any one of claims 1 to 9, the anode tail outlet of the hydrogen fuel cell being in communication with the hydrogen input line (2).

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