Performance test system and method based on urban gas pipe network connecting piece and key equipment sealing material in hydrogen-doped environment

Abstract

The invention belongs to the technical field of gas pipe networks, and particularly relates to a performance test system and method based on an urban gas pipe network connecting piece and key equipment sealing material in a hydrogen-doped environment. The system comprises a hydrogen cylinder, a natural gas cylinder, a gas mixing tank, a compressor, a horizontal stainless steel tank, an electric tracing band, a pressing sheet clamping device, a prestress loading measuring device, a hanging sheet clamping device, a pressure transmitter, a thermocouple temperature transmitter, a computer, a nitrogen cylinder, a flame arrester and a hydrogen concentration detector. The hydrogen cylinder and the natural gas cylinder are respectively communicated with the gas mixing tank, an outlet of the gas mixing tank is communicated with the horizontal stainless steel tank after passing through the compressor, and the nitrogen tank is respectively communicated with the horizontal stainless steel tank, the hydrogen cylinder and the natural gas cylinder; an electric tracing band, a pressing sheet clamping device, a prestress loading measuring device, a hanging sheet clamping device, a pressure transmitter and a thermocouple temperature transmitter are arranged in the horizontal stainless steel tank. The system achieves the purpose of constant temperature control.

Description

Technical Field

[0001] The present invention relates to the technical field of gas pipe networks, and in particular to a performance testing system and method based on a hydrogen-doped environment for city gas pipe network connectors and key equipment sealing materials. Background Art

[0002] The description of the background technology in the present invention belongs to the related technology related to the present invention, which is only used to illustrate and facilitate the understanding of the invention content of the present invention, and should not be understood as the applicant explicitly believes or inferred that the applicant believes that it is the prior art of the present invention on the filing date of the first application.

[0003] With the development of green hydrogen technology, the cost of green hydrogen is expected to be reduced on a large scale. Hydrogen-blended transportation is conducive to expanding the consumption channels of green hydrogen, helping to achieve deep carbon reduction goals and reduce carbon emissions during natural gas combustion. The urban gas pipeline system has good development space in hydrogen-blended transportation. At present, the main research and inventions are concentrated on the hydrogen applicability and compatibility of metal pipes, and there is still insufficient attention to the hydrogen-blended adaptability of seals and connectors.

[0004] There are many connection joints in the medium and low pressure pipeline network of urban gas, and there are many types of key equipment such as self-closing valves, diaphragm meters, and pressure regulators. The sealing materials are mostly made of rubber. Hydrogen is a small molecule gas relative to natural gas. The pressure range of medium and low pressure gas pipelines is between 3500kpa-0.4MPa. Under the influence of pipeline transportation temperature, pressure, compressive stress load and different hydrogen blending ratios, the performance of polymer sealing materials may change, resulting in poor sealing at the joints and key equipment connection parts. Hydrogen-blended natural gas may leak on a large scale. If the hydrogen-blended natural gas leaks at the urban end and is not handled in time, it will cause certain safety hazards. It is necessary to invent a method to test the influence of the above key factors on the performance of polymer sealing materials, and also provide a more practical test device for simulating the performance test of sealing materials under actual operating conditions. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a performance testing system and method based on urban gas pipeline connectors and key equipment sealing materials in a hydrogen-doped environment, so as to solve the performance testing environment simulation problem of urban gas medium and low pressure environment hydrogen-doped pipeline connectors and key equipment sealing materials proposed in the above background technology.

[0006] A performance test system based on the hydrogen-doped environment of the city gas pipe network connectors and key equipment sealing materials, including: hydrogen cylinders, natural gas cylinders, gas mixing tanks, compressors, horizontal stainless steel tanks, electric heating cables, sheet clamping devices, prestressed loading measuring devices, hanging sheet clamping devices, pressure transmitters, thermocouple temperature transmitters, computers, nitrogen cylinders, flame arresters and hydrogen concentration detectors; The hydrogen cylinder and the natural gas cylinder are connected to the gas mixing tank respectively, and the outlet of the gas mixing tank is connected to the horizontal stainless steel tank after passing through the compressor; the nitrogen tank is connected to the horizontal stainless steel tank, the hydrogen cylinder and the natural gas cylinder respectively; The horizontal stainless steel tank is provided with an electric heating belt, a sheet clamping device, a prestressed loading measuring device, a hanging sheet clamping device, a pressure transmitter and a thermocouple temperature transmitter; the electric heating belt, the pressure transmitter and the thermocouple temperature transmitter are respectively connected to computer signals; A hydrogen pipeline flow meter is provided at the outlet of the hydrogen cylinder, and a natural gas pipeline flow meter is provided at the outlet of the natural gas cylinder; a hydrogen concentration detector is connected to the gas mixing tank; the hydrogen pipeline flow meter, the natural gas pipeline flow meter and the hydrogen concentration detector are respectively connected to computer signals; The prestressed loading measuring device comprises: a flange and a bolt dynamometer; The sheet clamping device comprises: a circular flange connected to a prestressing loading measuring device to jointly compress and measure the prestressing value; The hanging piece clamping device comprises bolts and steel plates for clamping the hanging piece.

[0007] Furthermore, a hydrogen cylinder outlet valve is provided at the outlet of the hydrogen cylinder; a natural gas cylinder outlet valve is provided at the outlet of the natural gas cylinder; a mixing tank front valve is provided at the inlet of the mixing tank; a nitrogen cylinder to horizontal stainless steel tank outlet valve is provided between the nitrogen cylinder and the horizontal stainless steel tank; a nitrogen cylinder to hydrogen tank outlet valve is provided between the nitrogen cylinder and the hydrogen cylinder; a nitrogen cylinder to natural gas tank outlet valve is provided between the nitrogen cylinder and the natural gas cylinder; a compressor inlet valve is provided between the mixing tank and the compressor; a compressor outlet valve is provided between the compressor and the horizontal stainless steel tank; and a vent valve is provided at the front end of the flame arrester.

[0008] A performance testing method for city gas pipe network connectors and key equipment sealing materials in a hydrogen-doped environment comprises the following steps: S1: By adjusting the valves and flow control valves of hydrogen and natural gas cylinders, a hydrogen-blended mixed gas is formed; S2: Simulate the prestressed environment of the seal by making and installing the test specimens; S3: Build a closed constant temperature environment by installing a horizontal stainless steel tank and an electric heater; S4: The pressurized mixed gas is continuously input into the horizontal stainless steel tank through the compressor to form a constant pressure space; S5: After establishing a stable constant temperature and pressure environment, record the test time; S6: After the seal test is completed, gas replacement and safe discharge are carried out.

[0009] Furthermore, step S1 specifically includes the following steps: According to the hydrogen and natural gas ratio parameters and test requirements, calculate the required pressure values ​​of hydrogen and natural gas respectively; open the hydrogen cylinder valve and flow control valve, control the flow meter reading within the test requirements, and input natural gas into the mixing tank until the pressure reaches the calculated pressure value; in the same way, input the gas in the hydrogen mixed gas cylinder into the mixing tank; use the hydrogen concentration detector to analyze the hydrogen content in the mixing tank and adjust it until the ratio of natural gas and hydrogen mixed gas meets the test requirements.

[0010] Furthermore, step S2 specifically includes the following steps: According to different experimental conditions, two seal test specimens of the same size are made. One test specimen is placed in a hanging plate clamping device and is in a state without preload pressure, and the other test specimen is placed in a pressing plate clamping device. The prestressed loading measuring device is used to simulate the seal pressure environment.

[0011] Furthermore, step S3 specifically includes the following steps: The two parts of the horizontal stainless steel tank form a sealed environment; the electric heating inside the horizontal stainless steel tank is powered on for heating; the preheating temperature is set in the computer, the temperature of the mixed gas space in the stainless steel tank is measured by a thermocouple temperature sensor, the temperature signal is transmitted to the computer, and the heating temperature of the electric heating tape is controlled by the computer.

[0012] Furthermore, step S4 specifically includes the following steps: The vent valve and nitrogen valve are in the closed state, and the inlet and outlet valves of the compressor are opened to form a passage between the compressor and the horizontal stainless steel tank; the compressor is started, and the ambient pressure of the mixed gas space is measured by the pressure sensor inside the horizontal stainless steel tank. When the test ambient pressure value preset in the computer is reached, the inlet valve of the horizontal stainless steel tank and the compressor are closed in turn to maintain the constant pressure state of the horizontal stainless steel tank.

[0013] Furthermore, step S5 specifically includes the following steps: According to the seal test requirements, the test time is recorded by the computer. When the pressure inside the horizontal stainless steel tank is 5% lower than the pressure setting value required for the test, the mixed gas is pressurized according to S1 and S4 to ensure constant pressure inside the horizontal stainless steel tank.

[0014] Furthermore, step S6 specifically includes the following steps: Keep the valve from the horizontal stainless steel tank to the compressor room closed, open the vent pipe valve, and open the outlet valve from the nitrogen bottle to the horizontal stainless steel tank after venting for 5 minutes, and use the pressurized nitrogen in the nitrogen bottle to replace the mixed gas in the horizontal stainless steel tank and the pipeline with nitrogen; open the outlet valves of the nitrogen bottle to the hydrogen bottle outlet pipe and the nitrogen bottle to the natural gas bottle outlet pipe in turn to replace hydrogen and natural gas with nitrogen, and discharge the gas into the atmosphere through the vent pipe.

[0015] The embodiments of the present invention have the following beneficial effects: The present invention provides a performance testing system and method for city gas pipe network connectors and key equipment sealing materials in a hydrogen-doped environment, which solves the problem of simulating the performance testing environment for city gas medium and low pressure hydrogen-doped pipeline connectors and key equipment sealing materials.

[0016] Prestressed loading measurement simulation device for seal test specimens. The clamping device should be placed outside the flange of the horizontal stainless steel tank to facilitate the compression of the seal test specimen; the prestressed loading measurement device (including bolt dynamometer) is used to simulate the pressure environment of the seal, and the bolt dynamometer is used to measure the stress loading value.

[0017] Overall heating constant temperature system. The electric heating cables wrapped around the two parts of the horizontal stainless steel tank can be easily plugged in and out through the connecting plug. After connection, an overall heating constant temperature system can be formed, which has achieved the purpose of constant temperature control of the mixed gas environment temperature in the horizontal stainless steel tank to meet the test requirements.

[0018] Simple and safe venting system. Close all valves between the horizontal stainless steel tank and the compressor to achieve isolation; open the venting valve to vent the gas through the mixed gas pressure in the horizontal stainless steel tank; after venting for 5 minutes, when the mixed gas pressure in the horizontal stainless steel tank is consistent with the external environmental pressure of the horizontal stainless steel tank, open the nitrogen tank outlet control valve to replace the mixed gas in the horizontal stainless steel tank with the pressurized nitrogen in the nitrogen tank, and after completing the gas replacement of hydrogen and natural gas, close the nitrogen bottle outlet valve. According to this operation, the gas replacement of nitrogen with hydrogen pipeline and natural gas pipeline can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a performance test system based on city gas pipe network connectors and key equipment sealing materials in a hydrogen-doped environment in the present invention; Figure 2 It is a structural schematic diagram of a tablet clamping device in a performance test system of a city gas network connector and a key equipment sealing material in a hydrogen-doped environment according to the present invention; Figure 3 It is a structural schematic diagram of a hanging piece clamping device in a performance test system of a city gas pipe network connector and a key equipment sealing material in a hydrogen-doped environment according to the present invention; Figure 4 The present invention is a schematic structural diagram of a prestressed loading measurement device in a performance testing system based on a city gas network connector and a key equipment sealing material in a hydrogen-doped environment. DETAILED DESCRIPTION

[0020] The present application is further described below in conjunction with embodiments.

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, in the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. Different embodiments can be replaced or combined, and for ordinary technicians in this field, other implementation methods can be obtained based on these embodiments without creative work.

[0022] A performance test system based on the hydrogen-doped environment of the city gas pipe network connector and the sealing material of the key equipment, comprising: a hydrogen cylinder 1, a natural gas cylinder 2, a gas mixing tank 9, a compressor 11, a horizontal stainless steel tank 13, an electric heating belt 15, a sheet clamping device 16, a prestressed loading measuring device 17, a hanging sheet clamping device 18, a pressure transmitter 19, a thermocouple temperature transmitter 20, a computer 21, a nitrogen cylinder 22, a flame arrester 27 and a hydrogen concentration detector 29; The hydrogen cylinder 1 and the natural gas cylinder 2 are respectively connected to the gas mixing tank 9, and the outlet of the gas mixing tank 9 is connected to the horizontal stainless steel tank 13 after passing through the compressor 11; the nitrogen tank 22 is respectively connected to the horizontal stainless steel tank 13, the hydrogen cylinder 1 and the natural gas cylinder 2; The horizontal stainless steel tank 13 is provided with an electric heating belt 15 (with an electric heating belt connection plug 28), a sheet clamping device 16, a prestressed loading measuring device 17, a hanging sheet clamping device 18, a pressure transmitter 19 and a thermocouple temperature transmitter 20; the electric heating belt 15, the pressure transmitter 19 and the thermocouple temperature transmitter 20 are respectively connected to the computer 21 for signal; the horizontal stainless steel tank 13 is provided with a heat preservation layer 14; A hydrogen pipeline flowmeter 5 is provided at the outlet of the hydrogen cylinder 1, and a natural gas pipeline flowmeter 6 is provided at the outlet of the natural gas cylinder; a hydrogen concentration detector 29 is connected to the mixing tank 9; the hydrogen pipeline flowmeter 5, the natural gas pipeline flowmeter 6 and the hydrogen concentration detector are respectively connected to the computer 21 for signal. Combined with Figure 2-4 The prestressed loading measuring device includes: a flange 171 and a bolt dynamometer 172 .

[0023] The sheet pressing clamping device comprises: a circular flange 161 (including an annular groove 163 and a bolt hole 162), which is connected to a prestress loading measuring device to jointly press and measure the prestress value.

[0024] The hanging plate clamping device comprises: a bolt 181 and a steel plate 182, which are used to clamp the hanging plate.

[0025] In some embodiments of the present invention, a hydrogen cylinder outlet valve 3 is provided at the outlet of the hydrogen cylinder 1; a natural gas cylinder outlet valve 4 is provided at the outlet of the natural gas cylinder 2; a mixing tank front valve 8 (a four-way valve 7 is provided at the front end) is provided at the inlet of the mixing tank 9; a nitrogen cylinder to horizontal stainless steel tank outlet valve 23 is provided between the nitrogen cylinder 22 and the horizontal stainless steel tank 13; a nitrogen cylinder to hydrogen tank outlet valve 24 is provided between the nitrogen cylinder 22 and the hydrogen cylinder 1; a nitrogen cylinder to natural gas tank outlet valve 25 is provided between the nitrogen cylinder 22 and the natural gas cylinder 2; a compressor inlet valve 10 is provided between the mixing tank 9 and the compressor 11; a compressor outlet valve 12 is provided between the compressor 11 and the horizontal stainless steel tank 13; and a vent valve 26 is provided at the front end of the flame arrester 27.

[0026] A performance testing method for city gas pipe network connectors and key equipment sealing materials in a hydrogen-doped environment comprises the following steps: S1: By adjusting the valves and flow control valves of hydrogen and natural gas cylinders, a hydrogen-blended mixed gas is formed; S2: Simulate the prestressed environment of the seal by making and installing the test specimens; S3: Build a closed constant temperature environment by installing a horizontal stainless steel tank and an electric heater; S4: The pressurized mixed gas is continuously input into the horizontal stainless steel tank through the compressor to form a constant pressure space; S5: After establishing a stable constant temperature and pressure environment, record the test time; S6: After the seal test is completed, gas replacement and safe discharge are carried out.

[0027] In some embodiments of the present invention, step S1 specifically includes the following steps: According to the hydrogen and natural gas ratio parameters and test requirements, calculate the required pressure values ​​of hydrogen and natural gas respectively; open the hydrogen cylinder valve and flow control valve, control the flow meter reading within the test requirements, and input natural gas into the mixing tank until the pressure reaches the calculated pressure value; in the same way, input the gas in the hydrogen mixed gas cylinder into the mixing tank; use the hydrogen concentration detector to analyze the hydrogen content in the mixing tank and adjust it until the ratio of natural gas and hydrogen mixed gas meets the test requirements.

[0028] In some embodiments of the present invention, step S2 specifically includes the following steps: According to different experimental conditions, two seal test specimens of the same size are made. One test specimen is placed in a hanging plate clamping device and is in a state without preload pressure, and the other test specimen is placed in a pressing plate clamping device. The prestressed loading measuring device is used to simulate the seal pressure environment.

[0029] In some embodiments of the present invention, step S3 specifically includes the following steps: The two parts of the horizontal stainless steel tank form a sealed environment; the electric heating inside the horizontal stainless steel tank is powered on for heating; the preheating temperature is set in the computer, the temperature of the mixed gas space in the stainless steel tank is measured by a thermocouple temperature sensor, the temperature signal is transmitted to the computer, and the heating temperature of the electric heating tape is controlled by the computer.

[0030] In some embodiments of the present invention, step S4 specifically includes the following steps: The vent valve and nitrogen valve are in the closed state, and the inlet and outlet valves of the compressor are opened to form a passage between the compressor and the horizontal stainless steel tank; the compressor is started, and the ambient pressure of the mixed gas space is measured by the pressure sensor inside the horizontal stainless steel tank. When the test ambient pressure value preset in the computer is reached, the inlet valve of the horizontal stainless steel tank and the compressor are closed in turn to maintain the constant pressure state of the horizontal stainless steel tank.

[0031] In some embodiments of the present invention, step S5 specifically includes the following steps: According to the seal test requirements, the test time is recorded by the computer. When the pressure inside the horizontal stainless steel tank is 5% lower than the pressure setting value required for the test, the mixed gas is pressurized according to S1 and S4 to ensure constant pressure inside the horizontal stainless steel tank.

[0032] In some embodiments of the present invention, step S6 specifically includes the following steps: Keep the valve from the horizontal stainless steel tank to the compressor room closed, open the vent pipe valve, and open the outlet valve from the nitrogen bottle to the horizontal stainless steel tank after venting for 5 minutes, and use the pressurized nitrogen in the nitrogen bottle to replace the mixed gas in the horizontal stainless steel tank and the pipeline with nitrogen; open the outlet valves of the nitrogen bottle to the hydrogen bottle outlet pipe and the nitrogen bottle to the natural gas bottle outlet pipe in turn to replace hydrogen and natural gas with nitrogen, and discharge the gas into the atmosphere through the vent pipe.

[0033] The present invention provides a performance testing system and method for city gas pipe network connectors and key equipment sealing materials in a hydrogen-doped environment, which solves the problem of simulating the performance testing environment for city gas medium and low pressure hydrogen-doped pipeline connectors and key equipment sealing materials.

[0034] Prestressed loading measurement simulation device for seal test specimens. The clamping device should be placed outside the flange of the horizontal stainless steel tank to facilitate the compression of the seal test specimen; the prestressed loading measurement device (including bolt dynamometer) is used to simulate the pressure environment of the seal, and the bolt dynamometer is used to measure the stress loading value.

[0035] Overall heating constant temperature system. The electric heating cables wrapped around the two parts of the horizontal stainless steel tank can be easily plugged in and out through the connecting plug. After connection, an overall heating constant temperature system can be formed, which has achieved the purpose of constant temperature control of the mixed gas environment temperature in the horizontal stainless steel tank to meet the test requirements.

[0036] Simple and safe venting system. Close all valves between the horizontal stainless steel tank and the compressor to achieve isolation; open the venting valve to vent the gas through the mixed gas pressure in the horizontal stainless steel tank; after venting for 5 minutes, when the mixed gas pressure in the horizontal stainless steel tank is consistent with the external environmental pressure of the horizontal stainless steel tank, open the nitrogen tank outlet control valve to replace the mixed gas in the horizontal stainless steel tank with the pressurized nitrogen in the nitrogen tank, and after completing the gas replacement of hydrogen and natural gas, close the nitrogen bottle outlet valve. According to this operation, the gas replacement of nitrogen with hydrogen pipeline and natural gas pipeline can be achieved.

[0037] A performance testing method for city gas pipe network connectors and key equipment sealing materials in a hydrogen-doped environment comprises the following steps: Step 1: Adjust the valves and flow control valves of the hydrogen and natural gas cylinders to form a mixed gas with a hydrogen volume ratio of 20%. The operation is as follows: According to the hydrogen and natural gas ratio parameters and the test requirements of the 20% volume ratio hydrogen-blended natural gas, calculate the required pressure values ​​of hydrogen and natural gas respectively according to the volume partial pressure; open the hydrogen cylinder valve and flow control valve, control the flow meter reading within the range required by the 20% hydrogen gas integral pressure test, and input natural gas into the mixing tank until the pressure reaches the calculated pressure value; in the same way, input the gas in the 20% volume ratio hydrogen mixed gas cylinder into the mixing tank; use the hydrogen concentration detector to analyze the hydrogen content in the mixing tank and adjust it until the ratio of hydrogen and natural gas mixed gas meets the 20% volume ratio test requirements.

[0038] Step 2: Simulate the prestress environment of the seal by making and installing the test specimens. The operation is as follows: According to different experimental conditions, make two seal test specimens of the same size. One test specimen is placed in the hanging plate clamping device. After being screw-clamped, it is in a state without prestressing pressure. The other test specimen is placed in the pressing plate clamping device. The prestressed loading measuring device (including bolt dynamometer) is used to simulate the seal pressure environment. See the attached for the specific structure. Figure 2-4 Step 3: Build a closed constant temperature environment by installing a horizontal stainless steel tank and an electric heater. The operation is as follows: bring the two parts of the horizontal stainless steel tank close together and tighten them with bolts to form a sealed environment; connect the electric heating tapes of the two parts of the horizontal stainless steel tank through a joint, and turn on the electric heating for heating; set the preheating temperature in the computer (taking 5°C as an example), measure the temperature of the mixed gas space in the stainless steel tank through a thermocouple temperature sensor, transmit the temperature signal to the computer, and control the heating temperature of the electric heating tape through the computer to meet the test environment temperature requirements.

[0039] Step 4: Continuously input the pressurized mixed gas into the horizontal stainless steel tank through the compressor to form a constant pressure space. The specific operations are as follows: the vent valve and the nitrogen valve are in the closed state, and the inlet and outlet valves of the compressor are opened to form a passage between the compressor and the horizontal stainless steel tank; start the compressor, and measure the ambient pressure of the mixed gas space through the pressure sensor in the horizontal stainless steel tank. After reaching the test ambient pressure value preset in the computer, close the inlet valve of the horizontal stainless steel tank and the compressor in turn to maintain the constant pressure state of the horizontal stainless steel tank.

[0040] Step 5: After building a stable constant temperature and pressure environment, record the test time. The specific operations are as follows: According to the seal test requirements, the computer records the test time. When the pressure inside the horizontal stainless steel tank is 5% lower than the pressure setting value required for the test, the mixed gas is pressurized according to steps 1 and 4 to ensure constant pressure inside the horizontal stainless steel tank.

[0041] Step six: After the seal test is completed, gas replacement and safe discharge are carried out. The specific operations are as follows: keep the valve from the horizontal stainless steel tank to the compressor room closed, open the vent pipe valve, and open the outlet valve from the nitrogen bottle to the horizontal stainless steel tank after venting for 5 minutes. Use the pressurized nitrogen in the nitrogen bottle to replace the mixed gas in the horizontal stainless steel tank and the pipeline with nitrogen; open the outlet valves of the nitrogen bottle to the hydrogen bottle outlet pipeline and the nitrogen bottle to the natural gas bottle outlet pipeline in turn to replace hydrogen and natural gas with nitrogen, and the gas is discharged into the atmosphere through the vent pipe.

[0042] It should be noted that the above embodiments can be freely combined as needed. The above description is only the preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A performance test system based on city gas pipe network connectors and key equipment sealing materials in a hydrogen-doped environment, characterized in that: include: Hydrogen cylinders, natural gas cylinders, gas mixing tanks, compressors, horizontal stainless steel tanks, electric heating cables, sheet clamping devices, prestressed loading measuring devices, hanging sheet clamping devices, pressure transmitters, thermocouple temperature transmitters, computers, nitrogen cylinders, flame arresters and hydrogen concentration detectors; The hydrogen cylinder and the natural gas cylinder are connected to the gas mixing tank respectively, and the outlet of the gas mixing tank is connected to the horizontal stainless steel tank after passing through the compressor; the nitrogen tank is connected to the horizontal stainless steel tank, the hydrogen cylinder and the natural gas cylinder respectively; The horizontal stainless steel tank is provided with an electric heating belt, a sheet clamping device, a prestressed loading measuring device, a hanging sheet clamping device, a pressure transmitter and a thermocouple temperature transmitter; the electric heating belt, the pressure transmitter and the thermocouple temperature transmitter are respectively connected to computer signals; A hydrogen pipeline flow meter is provided at the outlet of the hydrogen cylinder, and a natural gas pipeline flow meter is provided at the outlet of the natural gas cylinder; a hydrogen concentration detector is connected to the gas mixing tank; the hydrogen pipeline flow meter, the natural gas pipeline flow meter and the hydrogen concentration detector are respectively connected to computer signals; The prestressed loading measuring device comprises: a flange and a bolt dynamometer; The sheet clamping device comprises: a circular flange connected to a prestressing loading measuring device to jointly compress and measure the prestressing value; The hanging piece clamping device comprises bolts and steel plates for clamping the hanging piece.

2. The performance testing system based on the city gas pipe network connector and key equipment sealing materials in a hydrogen-doped environment according to claim 1; characterized in that: A hydrogen cylinder outlet valve is provided at the outlet of the hydrogen cylinder; a natural gas cylinder outlet valve is provided at the outlet of the natural gas cylinder; a mixing tank front valve is provided at the inlet of the mixing tank; a nitrogen cylinder to horizontal stainless steel tank outlet valve is provided between the nitrogen cylinder and the horizontal stainless steel tank; a nitrogen cylinder to hydrogen tank outlet valve is provided between the nitrogen cylinder and the hydrogen cylinder; a nitrogen cylinder to natural gas tank outlet valve is provided between the nitrogen cylinder and the natural gas cylinder; a compressor inlet valve is provided between the mixing tank and the compressor; a compressor outlet valve is provided between the compressor and the horizontal stainless steel tank; a vent valve is provided at the front end of the flame arrester.

3. A performance test method based on city gas pipe network connectors and key equipment sealing materials in a hydrogen-doped environment, characterized in that: The steps include: S1: By adjusting the valves and flow control valves of hydrogen and natural gas cylinders, a hydrogen-blended mixed gas is formed; S2: Simulate the prestressed environment of the seal by making and installing the test specimens; S3: Build a closed constant temperature environment by installing a horizontal stainless steel tank and an electric heater; S4: The pressurized mixed gas is continuously input into the horizontal stainless steel tank through the compressor to form a constant pressure space; S5: After establishing a stable constant temperature and pressure environment, record the test time; S6: After the seal test is completed, gas replacement and safe discharge are carried out.

4. The performance testing method based on the city gas pipe network connector and key equipment sealing material in a hydrogen-doped environment according to claim 3 is characterized in that: Step S1 specifically includes the following steps: According to the hydrogen and natural gas ratio parameters and test requirements, calculate the required pressure values ​​of hydrogen and natural gas respectively; open the hydrogen cylinder valve and flow control valve, control the flow meter reading within the test requirements, and input natural gas into the mixing tank until the pressure reaches the calculated pressure value; in the same way, input the gas in the hydrogen mixed gas cylinder into the mixing tank; use the hydrogen concentration detector to analyze the hydrogen content in the mixing tank and adjust it until the ratio of natural gas and hydrogen mixed gas meets the test requirements.

5. The performance testing method based on the city gas pipe network connector and key equipment sealing material in a hydrogen-doped environment according to claim 4 is characterized in that: Step S2 specifically includes the following steps: According to different experimental conditions, two seal test specimens of the same size are made. One test specimen is placed in a hanging plate clamping device and is in a state without preload pressure, and the other test specimen is placed in a pressing plate clamping device. The prestressed loading measuring device is used to simulate the seal pressure environment.

6. The performance testing method based on the city gas pipe network connector and key equipment sealing material in a hydrogen-doped environment according to claim 5 is characterized in that: Step S3 specifically includes the following steps: The two parts of the horizontal stainless steel tank form a sealed environment; the electric heating inside the horizontal stainless steel tank is powered on for heating; the preheating temperature is set in the computer, the temperature of the mixed gas space in the stainless steel tank is measured by a thermocouple temperature sensor, the temperature signal is transmitted to the computer, and the heating temperature of the electric heating tape is controlled by the computer.

7. The performance testing method based on the city gas pipe network connector and key equipment sealing material in a hydrogen-doped environment according to claim 6 is characterized in that: Step S4 specifically includes the following steps: The vent valve and nitrogen valve are in the closed state, and the inlet and outlet valves of the compressor are opened to form a passage between the compressor and the horizontal stainless steel tank; the compressor is started, and the ambient pressure of the mixed gas space is measured by the pressure sensor inside the horizontal stainless steel tank. When the test ambient pressure value preset in the computer is reached, the inlet valve of the horizontal stainless steel tank and the compressor are closed in turn to maintain the constant pressure state of the horizontal stainless steel tank.

8. The performance testing method based on the city gas pipe network connector and key equipment sealing material in a hydrogen-doped environment according to claim 7 is characterized in that: Step S5 specifically includes the following steps: According to the seal test requirements, the test time is recorded by the computer. When the pressure inside the horizontal stainless steel tank is 5% lower than the pressure setting value required for the test, the mixed gas is pressurized according to S1 and S4 to ensure constant pressure inside the horizontal stainless steel tank.

9. The performance testing method based on the city gas pipe network connector and key equipment sealing material in a hydrogen-doped environment according to claim 8 is characterized in that: Step S6 specifically includes the following steps: Keep the valve from the horizontal stainless steel tank to the compressor room closed, open the vent pipe valve, and open the outlet valve from the nitrogen bottle to the horizontal stainless steel tank after venting for 5 minutes, and use the pressurized nitrogen in the nitrogen bottle to replace the mixed gas in the horizontal stainless steel tank and the pipeline with nitrogen; open the outlet valves of the nitrogen bottle to the hydrogen bottle outlet pipe and the nitrogen bottle to the natural gas bottle outlet pipe in turn to replace hydrogen and natural gas with nitrogen, and discharge the gas into the atmosphere through the vent pipe.

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