Hydrogen-doped natural gas pipeline welding seam leakage monitoring device and using method

Abstract

A hydrogen-doped natural gas pipeline weld joint leakage monitoring device disclosed by the present invention comprises a shell, at least two inflation and deflation pipelines and a pressure sensor, the shell is cylindrical, the shell is used for hermetically sleeving the outer side of a hydrogen-doped natural gas pipeline ground section with a weld joint, and an isolation cavity is arranged between the inner wall of the shell and the outer wall of the hydrogen-doped natural gas pipeline ground section. The isolation cavity is used for accommodating inert gas; one end of the inflation and deflation pipeline is communicated with the isolation cavity, the other end of the inflation and deflation pipeline is communicated with the external environment, the inflation and deflation pipeline is provided with a block valve, and the inflation and deflation pipeline is used for inflating inert gas into the isolation cavity or discharging gas in the isolation cavity to the external environment; the detection end of the pressure sensor is located in the isolation cavity. The problems that an existing hydrogen-doped natural gas pipeline monitoring device is low in monitoring precision, and leaked hydrogen cannot be effectively treated can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of safety monitoring of hydrogen-doped natural gas pipelines, and in particular to a hydrogen-doped natural gas pipeline weld leakage monitoring device and a use method thereof. Background Art

[0002] In recent years, with the rapid development of the global economy and the sharp increase in energy consumption, the reserves of traditional fossil energy, mainly oil, natural gas and coal, have sharply decreased, and the greenhouse effect and environmental pollution problems have become increasingly serious. Hydrogen energy, as a high-quality renewable clean energy carrier, has the advantages of being clean, zero-carbon, pollution-free, high in energy storage density, wide sources and diverse applications. It has broad development prospects and application value in the future energy system architecture.

[0003] In the process of utilizing hydrogen energy, efficient, safe and large-scale transportation is an important part of the future promotion of hydrogen energy, which determines the application prospects of hydrogen energy in related fields such as industry and civil use. Using existing natural gas pipelines to carry out hydrogen blending transportation can achieve low-cost and large-scale hydrogen energy transportation, which is currently recognized as one of the reliable methods of hydrogen energy transportation in the world.

[0004] Existing natural gas pipelines are interconnected by welding different steel pipe sections to achieve long-distance transportation. There are welds at the contact points between pipelines. During the hydrogen-blended transportation process, due to the small size of hydrogen atoms, the hydrogen atoms sealed inside the pipeline will adsorb, penetrate, diffuse and destroy the materials of the pipeline and welds, thereby causing dangerous accidents such as pipeline leakage at the welds. In addition, when the leaked hydrogen is not immediately diffused into the atmosphere, or the pipeline is indoors (limited space), once the explosion limit of hydrogen is reached, it may cause more dangerous operation accidents such as explosions.

[0005] The internal structure of the weld itself is reconstructed relative to the pipeline itself. The special microstructure of the weld metal leads to a higher hydrogen capture capacity and a stronger hydrogen enrichment capacity, which makes it more prone to cracks, which in turn makes it easier for hydrogen atoms to penetrate outward from the weld, thus causing the above-mentioned dangerous conditions such as leakage and explosion. Therefore, it is necessary to develop hydrogen leakage monitoring and explosion-proof control devices at the welds of hydrogen-blended natural gas pipelines to further maintain the safe operation and large-scale transportation of hydrogen-blended natural gas pipelines.

[0006] At present, the monitoring and explosion-proof devices for hydrogen-blended natural gas pipelines generally have the following problems: (1) Concentration measurement is commonly used for leakage monitoring. Ordinary concentration sensors have limited accuracy and cannot monitor trace hydrogen leaks. Fiber optic sensors are expensive and are not suitable for long-distance, large-scale hydrogen-blended natural gas pipelines. (2) In addition to the technical means of controlling ventilation volume, existing devices lack the ability to deal with hydrogen after leakage. However, it is difficult to accurately control ventilation volume in open areas, which can easily cause hydrogen accumulation and even explosion. (3) The monitoring devices themselves generally lack hydrogen damage protection measures, which is not conducive to long-term use. Summary of the invention

[0007] The purpose of the present invention is to provide a hydrogen-blended natural gas pipeline weld leakage monitoring device to solve the problem that the existing hydrogen-blended natural gas pipeline monitoring device has low monitoring accuracy and cannot effectively handle hydrogen leakage.

[0008] The present invention is achieved through the following technical solutions:

[0009] A hydrogen-doped natural gas pipeline weld leakage monitoring device comprises: a shell, the shell is cylindrical, the shell is used to be sealed and sheathed on the outer side of the ground section of the hydrogen-doped natural gas pipeline having a weld, an isolation chamber is provided between the inner wall of the shell and the outer wall of the ground section of the hydrogen-doped natural gas pipeline, and the isolation chamber is used to accommodate inert gas; at least two charging and discharging pipes, one end of the charging and discharging pipes is connected to the isolation chamber, and the other end is connected to the external environment, the charging and discharging pipes are provided with a shut-off valve, and the charging and discharging pipes are used to charge inert gas into the isolation chamber, or to discharge the gas in the isolation chamber to the external environment; a pressure sensor, and the detection end of the pressure sensor is located in the isolation chamber.

[0010] Optionally, the isolation cavity is a cylindrical cavity, and the isolation cavity is coaxially opened with the shell.

[0011] Optionally, the shell includes an upper half shell and a lower half shell that are symmetrically arranged, and the upper half shell and the lower half shell can be embraced to form a cylindrical shape; the upper half shell and the lower half shell are tightly bonded to the outer wall of the ground section of the hydrogen-blended natural gas pipeline at the weld.

[0012] Optionally, an anti-hydrogen embrittlement layer is bonded to the inner walls of the upper half shell and the lower half shell.

[0013] Optionally, a bracket is provided at the bottom of the lower half shell, and the bottom of the bracket is used to contact the ground.

[0014] Optionally, the pressure sensor is arranged on the top of the upper half shell.

[0015] Optionally, there are two gas charging and discharging pipes, one of which is connected to the isolation chamber through the lower half shell, and the other of which is connected to the isolation chamber through the upper half shell.

[0016] Optionally, the shut-off valve is provided with a hand wheel.

[0017] Optionally, an inert gas bottle and an inert gas concentration detector are further included; the inert gas bottle and the inert gas concentration detector are detachably connected to the two gas charging and discharging pipes respectively.

[0018] A method for using any of the above-mentioned hydrogen-doped natural gas pipeline weld leakage monitoring devices comprises the following steps:

[0019] S1. Open all the shut-off valves and observe that the reading of the pressure sensor is ≤0.1MPa to confirm that the gas charging and discharging pipeline is connected to the isolation chamber;

[0020] S2, close the shutoff valve until only two of the gas charging and discharging pipes are connected to the isolation chamber, fill the isolation chamber with inert gas through one of the gas charging and discharging pipes, and observe that the reading of the pressure sensor is ≤0.3MPa;

[0021] S3, detecting the concentration of the inert gas at the orifice of another of the gas charging and discharging pipes until the isolation chamber is filled with the inert gas;

[0022] S4, gradually reducing the air intake of the gas charging and discharging pipe filled with inert gas through the cut-off valve, and when the indication of the pressure sensor is observed to be 0.2 MPa, closing all the cut-off valves;

[0023] S5. Observe the indication of the pressure sensor. When the indication is stable and ≤0.2MPa, the weld is not leaking. When the indication gradually increases and is greater than 0.2MPa, the weld is leaking.

[0024] S6. When the weld leaks, gradually open any one of the cut-off valves to discharge the gas in the isolation chamber to the external environment, observe that the reading of the pressure sensor is ≤0.1MPa, and then repeat steps S2-S5;

[0025] S7. When the weld leaks and the indication of the pressure sensor is ≥0.5MPa, open the plurality of shut-off valves to implement emergency evacuation.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] The invention provides a hydrogen-doped natural gas pipeline weld leakage monitoring device. By setting a shell, the shell is sealed and fitted on the outer side of the weld of the ground section of the hydrogen-doped natural gas pipeline, and an isolation chamber is opened inside. The weld sealing cover is arranged in the isolation chamber to prevent the pressure of the external environment from affecting the monitoring accuracy. On this basis, by setting a pressure sensor and connecting its detection end with the isolation chamber, the pressure in the isolation chamber can be monitored accurately and timely to determine whether the weld is leaking and the leakage situation only by monitoring the pressure sensor. On this basis, by setting at least two gas charging and discharging pipelines, the gas charging and discharging pipelines are connected with the isolation chamber, and a shut-off valve is arranged, so that gas can be supplied to the isolation chamber through the gas charging and discharging pipelines. The cavity is filled with inert gas, and a stable initial pressure is provided for the isolation cavity, so as to monitor whether there is a pressure change in the isolation cavity, and when a leak occurs, the gas in the isolation cavity can be discharged to the external environment in time through the filling and discharging pipes. Since the isolation cavity is filled with inert gas in advance, the hydrogen in the discharged gas is entrained by a large amount of inert gas, which effectively avoids the accumulation explosion caused by direct contact between the discharged hydrogen and the oxygen in the air, so as to achieve safe venting. Through the mutual cooperation of the above-mentioned features, the hydrogen-blended natural gas pipeline weld leakage monitoring device can effectively solve the problem of low monitoring accuracy and inability to effectively deal with hydrogen leakage in the existing hydrogen-blended natural gas pipeline monitoring devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0029] Figure 1 is a schematic diagram of a surface section of a hydrogen-blended natural gas pipeline having a weld;

[0030] Figure 2 A schematic diagram of a hydrogen-blended natural gas pipeline weld leakage monitoring device provided by an embodiment of the present invention;

[0031] Figure 3 A front cross-sectional schematic diagram of a hydrogen-blended natural gas pipeline weld leakage monitoring device provided by an embodiment of the present invention;

[0032] Figure 4 A schematic top-sectional view of a hydrogen-blended natural gas pipeline weld leakage monitoring device provided by an embodiment of the present invention;

[0033] Figure 5 A side sectional schematic diagram of a hydrogen-blended natural gas pipeline weld leakage monitoring device provided in an embodiment of the present invention.

[0034] Marks and corresponding parts names in the attached drawings:

[0035] 1-ground section of hydrogen-blended natural gas pipeline; 2-weld; 10-shell; 101-upper half shell; 102-lower half shell; 11-isolation chamber; 12-anti-hydrogen embrittlement layer; 20-charging and discharging pipeline; 21-shutoff valve; 211-handwheel; 30-pressure sensor; 40-bracket. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0037] Please refer to Figures 1 to 5 The embodiment of the present invention provides a hydrogen-doped natural gas pipeline weld leakage monitoring device, comprising: a shell 10, the shell 10 is cylindrical, the shell 10 is used to be sealed and sheathed on the outer side of the ground section 1 of the hydrogen-doped natural gas pipeline having a weld 2, an isolation chamber 11 is provided between the inner wall of the shell 10 and the outer wall of the ground section 1 of the hydrogen-doped natural gas pipeline, and the isolation chamber 11 is used to accommodate inert gas; second, at least two gas charging and discharging pipes 20, one end of the gas charging and discharging pipe 20 is connected to the isolation chamber 11, and the other end is connected to the external environment, the gas charging and discharging pipe 20 is provided with a shut-off valve 21, and the gas charging and discharging pipe 20 is used to fill the isolation chamber 11 with inert gas, or to discharge the gas in the isolation chamber 11 to the external environment; third, a pressure sensor 30, and the detection end of the pressure sensor 30 is located in the isolation chamber 11.

[0038] The hydrogen-doped natural gas pipeline weld leakage monitoring device provided in this embodiment is provided with a shell 10, which is sealed and sheathed on the outer side of the ground section 1 of the hydrogen-doped natural gas pipeline having a weld 2, and an isolation chamber 11 is provided inside, and the weld 2 is sealed and covered in the isolation chamber 11 to prevent the pressure of the external environment from affecting the monitoring accuracy. On this basis, a pressure sensor 30 is provided, and its detection end is connected with the isolation chamber 11. Only by monitoring the pressure in the isolation chamber 11 through the pressure sensor 30 can it be accurately and timely monitored whether the weld 2 is leaking and what the leakage situation is; on this basis, at least two gas charging and discharging pipes 20 are provided, so that the gas charging and discharging pipes 20 are connected with the isolation chamber, and a shut-off valve 21 is provided. 0 can fill the isolation chamber 11 with inert gas and provide a stable initial pressure for the isolation chamber 11, so as to monitor whether there is a pressure change in the isolation chamber 11, and when leakage occurs, the gas in the isolation chamber 11 can be discharged to the external environment in time through the gas filling and discharging pipe 20. Since the isolation chamber 11 is filled with inert gas in advance, the hydrogen in the discharged gas is engulfed by a large amount of inert gas, which effectively avoids the accumulation explosion caused by the direct contact between the discharged hydrogen and the oxygen in the air, so as to achieve safe venting. Through the mutual cooperation of the above-mentioned features, the hydrogen-blended natural gas pipeline weld leakage monitoring device can effectively solve the problem that the existing hydrogen-blended natural gas pipeline monitoring device has low monitoring accuracy and cannot effectively deal with the leakage of hydrogen.

[0039] It should be noted that the material of the housing 10 can be any high-grade steel material in the prior art.

[0040] It should be noted that the above-mentioned inert gas is preferably nitrogen.

[0041] Preferably, in order to further improve the monitoring accuracy of the pressure sensor 30 , the isolation chamber 11 is a cylindrical chamber, and the isolation chamber 11 is coaxially opened with the shell 10 .

[0042] In order to facilitate the installation of the shell 10, the shell 10 includes an upper half shell 101 and a lower half shell 102 that are symmetrically arranged. The upper half shell 101 and the lower half shell 102 can be embraced to form a cylindrical shape; the upper half shell 101 and the lower half shell 102 are tightly bonded; the upper half shell 101 and the lower half shell 102 are tightly bonded to the outer wall of the ground section 1 of the hydrogen-blended natural gas pipeline at the weld 2.

[0043] Through the above arrangement, the shell 10 is installed on the ground section 1 of the hydrogen-blended natural gas pipeline by means of bonding and embracing, thereby avoiding disassembly of both ends of the ground section 1 of the hydrogen-blended natural gas pipeline, and effectively improving the installation efficiency. The bonding method can effectively ensure the sealing between the shell 10 and the outer wall of the ground section 1 of the hydrogen-blended natural gas pipeline.

[0044] It should be noted that the adhesive may be any adhesive used for metal in the prior art, as long as the airtightness of the bonding point can be ensured, such as any room temperature curing polymer resin adhesive.

[0045] It should be noted that the above adhesive can be dissolved and peeled off by using organic solvents such as ethylene glycol, propylene glycol and acetone.

[0046] In order to prevent the leaked hydrogen from causing hydrogen damage to the inner wall of the shell 10 , a hydrogen embrittlement-proof layer 12 is bonded to the inner walls of the upper half shell 101 and the lower half shell 102 .

[0047] It should be noted that the above-mentioned anti-hydrogen embrittlement layer 12 is an Al2O3 metal oxide coating.

[0048] In order to reduce the pressure load of the hydrogen-blended natural gas pipeline weld leakage monitoring device on the pipe wall of the ground section 1 of the hydrogen-blended natural gas pipeline to prevent the probability of weld 2 leakage from increasing, a bracket 40 is provided at the bottom of the lower half shell 102, and the bottom of the bracket 40 is used to contact the ground.

[0049] Preferably, for ease of observation, the pressure sensor 30 is disposed on the top of the upper half shell 101 .

[0050] Preferably, in order to simplify the structure and facilitate operation, the number of the air charging and discharging pipes 20 is two, one of the air charging and discharging pipes 20 is connected to the isolation chamber 11 through the lower half shell 102, and the other of the air charging and discharging pipes 20 is connected to the isolation chamber 11 through the upper half shell 101.

[0051] Preferably, in order to facilitate adjustment of the opening and closing degree of the shut-off valve 21 so as to effectively adjust the gas flow, the shut-off valve 21 is provided with a hand wheel 211 .

[0052] In order to supply inert gas and detect the content of inert gas in the isolation chamber 11, the hydrogen-blended natural gas pipeline weld leakage monitoring device also includes an inert gas bottle (not shown) and an inert gas concentration detector (not shown); the inert gas bottle and the inert gas concentration detector are respectively detachably connected to the two gas charging and discharging pipes 20.

[0053] Through the above arrangement, an inert gas bottle can be connected to the pipe mouth of one gas filling and discharging pipe 20 to fill the isolation chamber 11 with inert gas, and at the same time, an inert gas concentration detector is set at the pipe mouth of another gas filling and discharging pipe 20 to actually detect the inert gas concentration in the isolation chamber 11.

[0054] This embodiment also provides a method for using the above-mentioned hydrogen-doped natural gas pipeline weld leakage monitoring device, comprising the following steps:

[0055] S1, open all the shut-off valves 20, and observe that the reading of the pressure sensor 30 is ≤0.1MPa, so as to confirm that the gas charging and discharging pipe 20 is connected with the isolation chamber 11;

[0056] S2, close the shut-off valve 21 until only two of the gas charging and discharging pipes 20 are connected to the isolation chamber 11, fill the isolation chamber 11 with inert gas through one of the gas charging and discharging pipes 20, and observe that the reading of the pressure sensor 30 is ≤0.3MPa;

[0057] S3, detecting the concentration of the inert gas at the mouth of another gas charging and discharging pipe 20 until the isolation chamber 11 is filled with the inert gas;

[0058] S4, gradually reducing the air intake of the gas charging and discharging pipe 20 filled with inert gas through the cut-off valve 21, and when the indication of the pressure sensor 30 is observed to be 0.2 MPa, closing all the cut-off valves 21;

[0059] S5. Observe the reading of the pressure sensor 30. When the reading is stable and ≤0.2 MPa, the weld 2 is not leaking. When the reading gradually increases and is greater than 0.2 MPa, the weld 2 is leaking.

[0060] S6. When the weld 2 leaks, gradually open any one of the cut-off valves 21 to discharge the gas in the isolation chamber 11 to the external environment, observe that the reading of the pressure sensor 30 is ≤0.1 MPa, and then repeat steps S2-S5;

[0061] S7. When the weld 2 leaks and the reading of the pressure sensor 30 is ≥0.5 MPa, open the plurality of shut-off valves 21 to implement emergency evacuation.

[0062] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A hydrogen-blended natural gas pipeline weld leakage monitoring device, characterized in that: include: A shell (10), the shell (10) is cylindrical, the shell (10) is used to be sealed and sheathed on the outer side of the ground section of the hydrogen-blended natural gas pipeline where the weld is located, an isolation chamber (11) is provided between the inner wall of the shell (10) and the outer wall of the ground section of the hydrogen-blended natural gas pipeline, and the isolation chamber (11) is used to contain an inert gas; at least two gas charging and discharging pipes (20), one end of each of the gas charging and discharging pipes (20) being in communication with the isolation chamber (11) and the other end of each of the gas charging and discharging pipes (20) being in communication with the external environment, the gas charging and discharging pipes (20) being provided with a shutoff valve (21), and the gas charging and discharging pipes (20) being used to charge inert gas into the isolation chamber (11) or to discharge gas in the isolation chamber (11) to the external environment; A pressure sensor (30), wherein a detection end of the pressure sensor (30) is located in the isolation cavity (11).

2. The hydrogen-blended natural gas pipeline weld leakage monitoring device according to claim 1, characterized in that: The isolation cavity (11) is a cylindrical cavity, and the isolation cavity (11) is coaxially opened with the shell (10).

3. The hydrogen-blended natural gas pipeline weld leakage monitoring device according to claim 2, characterized in that: The housing (10) comprises an upper half shell (101) and a lower half shell (102) which are symmetrically arranged, and the upper half shell (101) and the lower half shell (102) can be embraced to form a cylindrical shape; The upper half shell (101) and the lower half shell (102) are tightly bonded; The upper half shell (101) and the lower half shell (102) are tightly bonded to the outer wall of the ground section of the hydrogen-blended natural gas pipeline at the weld.

4. The hydrogen-blended natural gas pipeline weld leakage monitoring device according to claim 3, characterized in that: The inner walls of the upper half shell (101) and the lower half shell (102) are bonded with a hydrogen embrittlement-proof layer (12).

5. The hydrogen-blended natural gas pipeline weld leakage monitoring device according to claim 3, characterized in that: A bracket (40) is provided at the bottom of the lower half shell (102), and the bottom of the bracket (40) is used to contact the ground.

6. The hydrogen-blended natural gas pipeline weld leakage monitoring device according to claim 3, characterized in that: The pressure sensor (30) is arranged on the top of the upper half shell (101).

7. The hydrogen-blended natural gas pipeline weld leakage monitoring device according to any one of claims 3 to 6, characterized in that: The number of the gas charging and discharging pipes (20) is two, one of the gas charging and discharging pipes (20) is connected to the isolation chamber (11) through the lower half shell (102), and the other of the gas charging and discharging pipes (20) is connected to the isolation chamber (11) through the upper half shell (101).

8. The hydrogen-blended natural gas pipeline weld leakage monitoring device according to claim 7, characterized in that: The cut-off valve (21) is provided with a hand wheel (211).

9. The hydrogen-blended natural gas pipeline weld leakage monitoring device according to claim 7, characterized in that: It also includes an inert gas bottle and an inert gas concentration detector; The inert gas bottle and the inert gas concentration detector are respectively detachably connected to the two gas charging and discharging pipes (20).

10. A method for using the hydrogen-blended natural gas pipeline weld leakage monitoring device as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1, opening all the shut-off valves (20), observing that the reading of the pressure sensor (30) is ≤ 0.1 MPa, to confirm that the gas charging and discharging pipeline (20) is connected to the isolation chamber (11); S2, closing the shutoff valve (21) until only two of the gas charging and discharging pipes (20) are connected to the isolation chamber (11), and filling the isolation chamber (11) with inert gas through one of the gas charging and discharging pipes (20), and observing that the reading of the pressure sensor (30) is ≤0.3 MPa; S3, detecting the concentration of the inert gas at the mouth of another of the gas charging and discharging pipes (20) until the isolation chamber (11) is filled with the inert gas; S4, gradually reducing the amount of air inlet into the gas charging and discharging pipe (20) filled with inert gas through the cut-off valve (21), and when the indication of the pressure sensor (30) is observed to be 0.2 MPa, closing all the cut-off valves (21); S5. Observe the indication of the pressure sensor (30). When the indication is stable and ≤0.2 MPa, the weld is not leaking. When the indication gradually increases and is greater than 0.2 MPa, the weld is leaking. S6. When the weld leaks, gradually open any one of the cut-off valves (21) to discharge the gas in the isolation chamber (11) to the external environment, observe that the reading of the pressure sensor (30) is ≤0.1 MPa, and then repeat steps S2-S5; S7. When the weld leaks and the reading of the pressure sensor (30) is ≥0.5 MPa, open the plurality of shut-off valves (21) to implement emergency evacuation.

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