Method and system for long-time pressure maintaining of gas detection branch of water electrolysis hydrogen production device

Abstract

The invention provides a long-time pressure maintaining method and system for a gas detection branch of a water electrolysis hydrogen production device, and belongs to the technical field of hydrogen energy equipment. The method comprises the following steps: storing qualified produced hydrogen in a buffer tank when equipment runs normally, and automatically supplying gas by the buffer tank to maintain the pressure maintaining state of a gas detection branch after the equipment is shut down; and if the pressure of the buffer tank is insufficient, the system is automatically switched to external nitrogen supply. The system comprises a hydrogen buffer tank, a nitrogen container, a pressure regulating module, a gas detection module, a PLC (Programmable Logic Controller) control module, a plurality of pressure sensors and a plurality of electromagnetic valves, and can realize automatic switching and pressure maintaining control of three gas supply branches. The system can keep the pressure of 2 bar in the detection pipeline not less than 24 hours in the shutdown state of equipment, has the advantages of automatic operation, high safety, quick restart, low operation cost and the like, and is suitable for improving the stability and the operation efficiency of the PEM water electrolysis system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cells, in particular to a method and system for long-time pressure maintenance of a gas detection branch of a water electrolysis hydrogen production device. BACKGROUND

[0002] Proton exchange membrane (PEM) water electrolysis hydrogen production technology is widely used in distributed green hydrogen production systems due to its high current density, fast response, small system volume, and other advantages.

[0003] In the operation of a PEM system, a gas detection module is used to monitor the content of trace amounts of oxygen, trace amounts of water, and other impurities in the hydrogen produced, which is a key unit for ensuring product gas purity and safe operation of the system.

[0004] Currently, the gas detection module usually needs to be continuously purged with high-purity hydrogen or inert gas to maintain probe stability and detection accuracy.

[0005] In the traditional approach, a nitrogen cylinder set needs to be connected to continue supplying gas after the PEM device is shut down, which not only increases the investment in supporting facilities, but also causes gas waste and complex operation, and cannot meet the current requirements for efficient and low-energy operation of hydrogen production equipment. SUMMARY

[0006] The purpose of the present application is to provide a method and system that can maintain the stable state of the detection branch gas for a long time in the shutdown state of the PEM device, thereby reducing gas consumption, reducing operating costs, and improving system safety and operating efficiency.

[0007] To achieve the above-mentioned purpose, the present application provides a technical solution: The present application provides a method for long-time pressure maintenance of a gas detection branch of a water electrolysis hydrogen production device, comprising the steps of: During normal operation of a PEM water electrolysis device, hydrogen from the PEM hydrogen production device is stored in a buffer tank; When the device is shut down, the control system automatically switches to hydrogen supplied by the buffer tank as the pressure maintaining gas for the gas detection branch, and adjusts the pressure to 2 bar through a gas pressure regulating module; When the pressure of the hydrogen from the PEM hydrogen production device is lower than 2 bar, automatically switch to nitrogen from an external nitrogen source for pressure maintenance, and adjust the pressure to 2 bar through a gas pressure regulating module.

[0008] The present application also provides a system for long-time pressure maintenance of a gas detection branch of a water electrolysis hydrogen production device, comprising: a buffer tank connected to the hydrogen output end of the hydrogen production device, the hydrogen output end of the hydrogen production device being provided with a first pressure transmitter; a nitrogen source; a gas pressure regulating module, an inlet section of the gas pressure regulating module is connected with the buffer tank and the nitrogen source respectively, the buffer tank is connected with the gas pressure regulating module through a first electromagnetic valve, and the nitrogen source is connected with the gas pressure regulating module through a second electromagnetic valve; a gas detection module, the gas detection module is provided with a micro oxygen probe and a micro water probe, an inlet end of the gas detection module is connected with an outlet end of the gas pressure regulating module, and the gas pressure regulating module adjusts the gas pressure of the buffer tank and the nitrogen source entering the gas detection module to 1 Bar-2 Bar, which is configured to: first branch gas supply: when the PEM device is shut down and when the pressure of the first pressure transmitter is ≥3 Bar, the first electromagnetic valve is opened, and the second electromagnetic valve is closed, hydrogen in the buffer tank is used as pressure maintaining gas, at the same time, the pressure of the gas detection module is monitored in real time, if the pressure of the gas detection module is 2 Bar, the first electromagnetic valve is closed, if the pressure of the gas detection module is <the target pressure, the first electromagnetic valve is opened, and the step is repeated to ensure that the pressure in the gas pressure regulating module is always the target pressure; second branch gas supply: when the PEM device is shut down and when the pressure of the first pressure transmitter is <3 Bar, the first electromagnetic valve is closed, and the second electromagnetic valve is opened, nitrogen in the nitrogen source is used as pressure maintaining gas, at the same time, the pressure of the gas detection module is monitored in real time, if the pressure of the gas detection module is the target pressure, the second electromagnetic valve is closed, if the pressure of the gas detection module is <the target pressure, the second electromagnetic valve is opened, and the step is repeated to ensure that the pressure in the gas detection module is always the target pressure.

[0009] Preferably, a second pressure transmitter is arranged between the nitrogen source and the second electromagnetic valve, when the pressure of the second pressure transmitter is <3 Bar, the second electromagnetic valve is closed, and a warning prompt appears at the operation panel of the PEM.

[0010] Preferably, a hydrogen output end of the hydrogen production device is connected with the gas pressure regulating module through a third electromagnetic valve, when the first branch gas supply is detected to be abnormal, the first branch gas supply is switched to direct gas supply of the hydrogen production device, that is, switched to third branch gas supply: the first electromagnetic valve and the second electromagnetic valve are both closed, and the third electromagnetic valve is opened, at the same time, the pressure of the gas detection module is monitored in real time, if the pressure of the gas detection module is the target pressure, the third electromagnetic valve is closed, if the pressure of the gas detection module is <the target pressure, the third electromagnetic valve is opened, and the step is repeated to ensure that the pressure in the gas pressure regulating module is always the target pressure.

[0011] As preferably, the buffer tank abnormality includes that the buffer tank is in a detection or maintenance state.

[0012] As preferably, the volume of the buffer tank ranges from 38 L to 50 L, and the design pressure of the buffer tank ranges from 10 Bar to 16 Bar.

[0013] As preferably, the system further comprises a first needle valve and a first pressure regulating valve, the inlet end of the first pressure regulating valve is connected with the branch outlet of the nitrogen source, the outlet end of the first pressure regulating valve is connected with a second electromagnetic valve and the first needle valve in parallel, respectively, and the first needle valve is connected between the outlet end of the first pressure regulating valve and the branch inlet of the buffer tank. The first needle valve is normally closed, and is opened only when manually intervened to realize reverse purging of nitrogen to the first branch.

[0014] As preferably, the electrolytic water hydrogen production device gas detection system further comprises a second needle valve, which is connected between the outlet end of the first pressure regulating valve and the inlet end of the third electromagnetic valve.

[0015] As preferably, the system further comprises a pressure protection module, the inlet end of the pressure protection module is connected with the outlet end of the gas detection module, the pressure protection module comprises a safety valve and a stop valve, and the pressure protection module ensures that all pressures adjusted by the gas pressure regulating module are within a reasonable range.

[0016] As preferably, the system further comprises a gas safety discharge module, the gas safety discharge module comprises a flame arrester, and the flame arrester is connected with the outlet end of the pressure protection module to ensure safe discharge of the exhaust gas of the electrolytic water hydrogen production device gas detection system.

[0017] The beneficial effects of the present application are as follows: 1. Safety is improved: Because most of the pressure maintaining gas of the detection system comes from qualified gas during normal production of the PEM device, there is no need to introduce a large amount of external gas (such as gas purchased or produced by other devices), thereby avoiding gas pollution or unsuitable conditions. When the pressure of the gas stored in the buffer tank is insufficient, a small amount of nitrogen in the nitrogen source is introduced to maintain pressure, and the nitrogen consumption is about 0.1 m 3 / h, so that the detection pipeline can be immediately put into use when it is restarted after shutdown, and about 1.5 hours of pipeline and instrument purging time can be saved after each long shutdown (12 hours) and restart.

[0018] 2. The pressure maintaining system of the present application is directly connected with the PEM, and a storage system (buffer tank) specially configured for the detection branch is arranged in the detection branch, and the detection system also has the function of external protection gas, thereby ensuring the integrity of the detection system.

[0019] 3, Ensure that the PEM in downtime, especially for a long time (hydrogen pressure retention maximum limit is 24 hours) can ensure that the detection probe in the detection system is not affected by the external environment, both to ensure the reliability of each probe, but also to ensure the cleanliness of each pipeline of the detection system, reduce the processing steps and consumption for the restart, shorten the gas purging time when the PEM restarts, thereby improving the overall equipment efficiency.

[0020] 4, The application realizes automatic control, does not need human operation, initial cost investment, reliable operation, and simple and efficient control logic. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is the structure of the pressure maintaining system in an embodiment.

[0022] Among them, 100, hydrogen production equipment; 101, first pressure transmitter; 102, third electromagnetic valve; 200, buffer tank; 201, first electromagnetic valve; 202, fourth pressure transmitter; 300, nitrogen source; 301, second electromagnetic valve; 302, second pressure transmitter; 303, first pressure regulating valve; 304, first needle valve; 305, second needle valve; 400, gas pressure regulating module; 401, second pressure regulating valve; 402, third pressure regulating valve; 500, gas detection module; 501, trace oxygen probe; 502, trace water probe; 503, third pressure transmitter; 600, pressure protection module, 601, safety valve; 602, stop valve; 700, gas safety discharge module; 701, flame arrester. DETAILED DESCRIPTION

[0023] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in conjunction with specific embodiments.

[0024] In the embodiment, the test method used is a conventional method unless otherwise specified, and the materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified.

[0025] The present application provides a kind of electrolytic water hydrogen production device gas detection branch long time pressure maintaining method, comprising the following steps: During normal operation of PEM water electrolysis equipment, hydrogen of the PEM hydrogen production equipment is stored in buffer tank 200; When the equipment is stopped, the hydrogen supplied by the buffer tank 200 is automatically switched to the pressure maintaining gas of the gas detection branch by the control system, and the pressure is adjusted to the target pressure by the gas pressure regulating module 400, and the target pressure range is 1Bar -2 Bar; When the pressure of hydrogen of the PEM hydrogen production device 100 is lower than 2 bar, it is automatically switched to pressure maintaining by nitrogen of the external nitrogen source 300, and the pressure is adjusted to the target pressure by the gas pressure regulating module 400.

[0026] As shown in Figure 1 The application also provides a system for realizing long-time pressure maintaining of the gas detection branch of the water electrolysis hydrogen production device, comprising: A buffer tank 200 connected to the hydrogen production device 100, wherein the hydrogen output end of the hydrogen production device 100 is provided with a first pressure transmitter 101; A nitrogen source 300; A gas pressure regulating module 400, the inlet section of the gas pressure regulating module 400 is connected to the buffer tank 200 and the nitrogen source 300 respectively, the buffer tank 200 is connected to the gas pressure regulating module 400 through a first electromagnetic valve 201, and the nitrogen source 300 is connected to the gas pressure regulating module 400 through a second electromagnetic valve 301; A gas detection module 500, which is provided with a trace oxygen probe 501 and a trace water probe 502, the inlet end of the gas detection module is connected to the outlet end of the gas pressure regulating module 400, the gas pressure regulating module 400 adjusts the gas pressure of the buffer tank 200 and the nitrogen source 300 entering the gas detection module 500 to the target pressure, and the target pressure ranges from 1 Bar to 2 Bar, which is configured to: First branch gas supply: when the PEM device is shut down and when the pressure of the first pressure transmitter 101 is ≥3 Bar, the first electromagnetic valve 201 is opened and the second electromagnetic valve 301 is closed, and the hydrogen in the buffer tank 200 is used as the pressure maintaining gas, at the same time, the pressure of the gas detection module 500 is monitored in real time, if the pressure of the gas detection module 500 is the target pressure, then the first electromagnetic valve 201 is closed, if the pressure of the gas detection module 500 is < the target pressure, then the first electromagnetic valve 201 is opened, and this step is repeated to ensure that the pressure in the gas pressure regulating module 400 is always the target pressure; more specifically, a third pressure transmitter 503 is arranged at the inlet of the gas detection module 500 for detecting the pressure of the gas detection module 500.

[0027] Second branch gas supply: when the PEM device is shut down and when the pressure of the first pressure transmitter 101 is < 3 Bar, the first electromagnetic valve 201 is closed, and the second electromagnetic valve 301 is opened, and the nitrogen in the nitrogen source 300 is used as a pressure maintaining gas, at the same time, the pressure of the gas detection module 500 is monitored in real time, if the pressure of the gas detection module 500 is the target pressure, the second electromagnetic valve 301 is closed, if the pressure of the gas detection module 500 is < the target pressure, the second electromagnetic valve 301 is opened, and the step is repeated to ensure that the pressure in the gas detection module 500 is always the target pressure.

[0028] In some embodiments, a second pressure transmitter 302 is provided between the nitrogen source 300 and the second electromagnetic valve 301, when the pressure of the second pressure transmitter 302 is < 3 Bar, the second electromagnetic valve 301 is closed, and a warning prompt appears at the operation panel of the PEM.

[0029] In some embodiments, the hydrogen output end of the hydrogen production device 100 is connected to the gas pressure regulating module 400 through a third electromagnetic valve 102, when the first branch gas supply is detected to be abnormal, the first branch gas supply is switched to direct gas supply of the hydrogen production device 100, that is, switched to the third branch gas supply: The first electromagnetic valve 201 and the second electromagnetic valve 301 are both closed, and the third electromagnetic valve 102 is opened, at the same time, the pressure of the gas detection module 500 is monitored in real time, if the pressure of the gas detection module 500 is 2 Bar, the third electromagnetic valve 102 is closed, if the pressure of the gas detection module 500 is < 2 Bar, the third electromagnetic valve 102 is opened, and the step is repeated to ensure that the pressure in the gas pressure regulating module 400 is always 2 Bar.

[0030] In some embodiments, the abnormality of the buffer tank 200 includes that the buffer tank 200 is in a detection or maintenance state.

[0031] In some embodiments, the volume of the buffer tank 200 ranges from 38L to 50L, and the design pressure of the buffer tank 200 is 10 Bar - 16 Bar.

[0032] In some embodiments, the electrolytic water hydrogen production device gas detection system further comprises a first needle valve 304 and a first pressure regulating valve 303, the inlet end of the first pressure regulating valve 303 is connected to the branch outlet of the nitrogen source 300, the outlet end of the first pressure regulating valve 303 is connected in parallel with the second electromagnetic valve 301 and the first needle valve 304, and the first needle valve 304 is connected across the outlet end of the first pressure regulating valve 303 and the branch inlet of the buffer tank 200. The first needle valve 304 is normally closed and only opens upon manual intervention to enable the reverse purge of nitrogen into the first branch.

[0033] In some embodiments, the electrolytic water hydrogen production device gas detection system further comprises a second needle valve 305, which is connected between the outlet end of the first pressure regulating valve 303 and the inlet end of the third solenoid valve 102.

[0034] In some embodiments, the electrolytic water hydrogen production device gas detection system further comprises a pressure protection module 600, the inlet end of which is connected to the outlet end of the gas detection module 500. The pressure protection module 600 is composed of a high-precision safety valve 601 and a stop valve. The valve leakage rate standard of the safety valve and the stop valve is GB / T4213-92, and the set pressure of the safety valve is 2.2 Bar. The pressure protection module 600 ensures that all the pressure adjusted by the gas pressure regulating module 400 is within a reasonable range.

[0035] More specifically, when the pressure maintaining system is running, the gas in the gas detection module 500 and the pressure protection module 600 is communicated. The safety set pressure of the pressure protection module 600 is set to 2.2 bar. When the pipeline pressure in the jurisdiction of the pressure protection module 600 is higher than this value, the safety valve 601 of the pressure protection module 600 will jump and release high-pressure gas to the outside of the pipeline. When the pressure is slightly less than 2.2 bar, the safety valve is closed, so that the gas pressure in the gas detection module 500 is kept less than 2.2 bar.

[0036] In addition, the gas pressure in the pipeline of the gas detection module 500 is set by the second pressure regulating valve 401 and the third pressure regulating valve 402 of the gas pressure regulating module 400, and the pressure value is 2 bar.

[0037] When the second pressure regulating valve 401 and the third pressure regulating valve 402 fail, the pressure protection module 600 is used to ensure that the gas pressure value in the pipeline is in a controlled state.

[0038] In some embodiments, the electrolytic water hydrogen production device gas detection system further comprises a gas safety discharge module 700, which includes a flame arrester 701 connected to the outlet end of the pressure protection module 600 to ensure the safe discharge of the exhaust gas of the electrolytic water hydrogen production device gas detection system.

[0039] In some embodiments, the buffer tank 200 is provided with a fourth pressure transmitter 202, when the gas is supplied, when the pressure of the first pressure transmitter 101 and the fourth pressure transmitter 202 are both < 3 Bar, the second branch is used to supply the gas, and if the pressure of the fourth pressure transmitter 202 is ≥ 3 Bar and the pressure of the fourth pressure transmitter 202 is < 3 Bar, it is necessary to overhaul the first electromagnetic valve and other valves on the first branch to check whether they are mistakenly closed or malfunctioning.

[0040] Figure 1 The valve symbols in the drawings are some standard symbols stipulated by the state in the process flow chart, which will not be described here.

[0041] In some embodiments, some needle valves are provided on the branches of the system, which are used as the cut-off of the gas in the pipeline (as cut-off valves, which can realize the unobstructed and cut-off of the gas in the pipeline on the pipeline under their jurisdiction).

[0042] For example, needle valves are connected at each pressure transmitter.

[0043] In some embodiments, some one-way valves are provided on the branches of the system, which are used to realize the one-way flow of the pipeline under their jurisdiction, and the gas cannot flow back.

[0044] It should be noted that the specific parameters or some reagents in the above embodiments are specific embodiments or preferred embodiments under the concept of the present application, and are not limited thereto; those skilled in the art can make adaptive adjustments within the concept and protection scope of the present application.

Claims

1. A method for long-time pressure maintaining of a gas detection branch of a hydrogen production device by electrolysis of water, characterized in that, The method comprises the steps of: During normal operation of the PEM water electrolysis device, hydrogen from the PEM hydrogen production device is stored in a buffer tank; When the device is shut down, the control system automatically switches to hydrogen supplied by the buffer tank as the pressure maintaining gas for the gas detection branch, and adjusts the pressure to the target pressure through the gas pressure regulating module, with the target pressure range being 1 Bar -2 Bar; When the pressure of the hydrogen from the PEM hydrogen production device is lower than the target pressure, the pressure is automatically maintained by nitrogen from an external nitrogen source, and the pressure is adjusted to the target pressure through the gas pressure regulating module.

2. A pressure maintenance system for implementing the method of claim 1, characterized by It comprises: a buffer tank connected to the hydrogen output end of the hydrogen production device, wherein the hydrogen output end of the hydrogen production device is provided with a first pressure transmitter; a nitrogen source; a gas pressure regulating module, wherein the inlet section of the gas pressure regulating module is connected to the buffer tank and the nitrogen source respectively, the buffer tank is connected to the gas pressure regulating module through a first electromagnetic valve, and the nitrogen source is connected to the gas pressure regulating module through a second electromagnetic valve; a gas detection module, wherein a trace oxygen probe and a trace water probe are arranged in the gas detection module, and the inlet end of the gas detection module is connected to the outlet end of the gas pressure regulating module; The gas pressure regulating module adjusts the gas pressure of the buffer tank and the nitrogen source entering the gas detection module to the target pressure, with the target pressure range being 1 Bar -2 Bar, and is specifically configured as follows: First branch gas supply: when the PEM device is shut down and the pressure of the first pressure transmitter is ≥3 Bar, open the first electromagnetic valve and close the second electromagnetic valve, use the hydrogen in the buffer tank as the pressure maintaining gas, at the same time, monitor the pressure of the gas detection module in real time, if the pressure of the gas detection module is the target pressure r, then close the first electromagnetic valve, if the pressure of the gas detection module is < the target pressure, open the first electromagnetic valve, repeat this step, and ensure that the pressure in the gas pressure regulating module is always the target pressure; Second branch gas supply: when the PEM device is shut down and the pressure of the first pressure transmitter is <3 Bar, close the first electromagnetic valve and open the second electromagnetic valve, use the nitrogen in the nitrogen source as the pressure maintaining gas, at the same time, monitor the pressure of the gas detection module in real time, if the pressure of the gas detection module is the target pressure, close the second electromagnetic valve, if the pressure of the gas detection module is < the target pressure, open the second electromagnetic valve, repeat this step, and ensure that the pressure in the gas detection module is always the target pressure.

3. The system of claim 2, wherein, A second pressure transmitter is arranged between the nitrogen source and the second electromagnetic valve, when the pressure of the second pressure transmitter is <3 Bar, the second electromagnetic valve is closed, and a warning prompt appears on the operation panel of the PEM.

4. The system of claim 2, wherein, The hydrogen output end of the hydrogen production device is connected to the gas pressure regulating module through a third electromagnetic valve, when the first branch gas supply is detected to be abnormal, the first branch gas supply is switched to direct gas supply from the hydrogen production device, i.e. switched to third branch gas supply: The first electromagnetic valve and the second electromagnetic valve are closed, the third electromagnetic valve is opened, and the pressure of the gas detection module is monitored in real time; if the pressure of the gas detection module is the target pressure, the third electromagnetic valve is closed; if the pressure of the gas detection module is less than the target pressure, the third electromagnetic valve is opened, and the step is repeated to ensure that the pressure in the gas pressure regulating module is always the target pressure.

5. The system of claim 4, wherein, The buffer tank anomaly includes that the buffer tank is in a detection or maintenance state.

6. The system of claim 2, wherein, The volume of the buffer tank ranges from 38L to 50L, and the design pressure of the buffer tank is 10Bar-16Bar.

7. The system of claim 2, wherein, The electrolytic water hydrogen production device gas detection system further comprises a first needle valve and a first pressure regulating valve, the inlet end of the first pressure regulating valve is connected with the branch outlet of the nitrogen source, the outlet end of the first pressure regulating valve is connected with the second electromagnetic valve and the first needle valve in parallel, and the first needle valve is connected between the outlet end of the first pressure regulating valve and the branch inlet of the buffer tank. The first needle valve is normally closed and is opened only under manual intervention to realize reverse purging of nitrogen to the first branch.

8. The system of claim 7, wherein, The electrolytic water hydrogen production device gas detection system further comprises a second needle valve, which is connected between the outlet end of the first pressure regulating valve and the inlet end of the third electromagnetic valve.

9. The system of claim 2, wherein, The electrolytic water hydrogen production device gas detection system further comprises a pressure protection module, the inlet end of the pressure protection module is connected with the outlet end of the gas detection module, the pressure protection module comprises a safety valve and a stop valve, and the pressure protection module is used to ensure that all pressures adjusted by the gas pressure regulating module are within a reasonable range.

10. The system of claim 9, wherein, The electrolytic water hydrogen production device gas detection system further comprises a gas safety discharge module, the gas safety discharge module comprises a flame arrester, and the flame arrester is connected with the outlet end of the pressure protection module to ensure safe discharge of the exhaust gas of the electrolytic water hydrogen production device gas detection system.

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