Hydrogen gas leak detection system from high-pressure hydrogen gas piping

Abstract

To provide a hydrogen leak detection system that prevents hydrogen leakage into the engine room and can quickly detect hydrogen leakage from internal pipes, even when hydrogen fuel is supplied to the engine room by high-pressure injection. [Solution] The double-walled pipe has a structure in which high-pressure hydrogen gas flows through the inner pipe 101 and nitrogen gas flows through the outer annular section 104. The pressure of the nitrogen gas reaching the outlet of the outer annular section 104 is adjusted to remain lower than the pressure of the hydrogen gas in the inner pipe 101 and higher than atmospheric pressure. A hydrogen gas sensor 106 for detecting hydrogen leakage is installed in the piping on the outlet side of the outer annular section 104.

Description

Technical Field

[0001] The present invention relates to a hydrogen leakage detection system, and more particularly to a hydrogen leakage detection system that can safely supply hydrogen fuel to a marine engine such as a diesel engine.

Background Art

[0002] In Patent Document 1, a pipe for sending a combustible gas to a marine boiler is made into a double pipe, and nitrogen is enclosed in the annular portion at a pressure higher than that of the combustible gas in the inner pipe, thereby preventing the combustible gas from leaking into the annular portion and monitoring the pressure in the annular portion to issue an alarm. [[ID=It]]

[0003] However, for the supply of hydrogen fuel to a diesel engine, high-pressure injection (for example, 30 MPa) is required. Since the pressure in the inner pipe of the double pipe is high, it is necessary to make the pressure in the annular portion even higher. However, increasing the pressure makes the equipment heavy and causes a problem of increased cost.

[0004] Also, in Patent Document 2, nitrogen is passed through the annular portion of a double pipe (conduit) of a low-pressure hydrogen gas supply line of 0.1 to 􀀞1 MPa, and hydrogen sensors are arranged at the ends of a plurality of branch pipes to detect hydrogen leakage. However, in this method, when the pressure in the inner pipe is high-pressure hydrogen gas (for example, 30 MPa), if an attempt is made to make the annular portion (outer pipe) even higher in pressure, it is difficult to manufacture the equipment due to the installation of a plurality of branch pipes.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, the present invention aims to solve the above problems and provide a hydrogen leak detection system that can prevent hydrogen leakage into the marine engine room and quickly detect hydrogen leakage from the internal pipe, even when hydrogen fuel is supplied to the marine engine room at high pressure injection (e.g., 30 MPa).

[0007] Furthermore, other problems of the present invention will become clear from the following description. [Means for solving the problem]

[0008] The above problems are solved by the following inventions.

[0009] 1. A hydrogen gas leak detection system from a high-pressure hydrogen gas pipeline that supplies high-pressure hydrogen gas fuel to a marine engine, wherein the hydrogen gas fuel pipeline located within the gas safety engine area is constructed as a double-walled pipe, The starting point of the double-pipe region is near a fuel control unit installed in a marine engine within the gas safety engine area, and the ending point of the double-pipe region is the boundary point of the gas safety engine area or its vicinity. The structure is such that high-pressure hydrogen gas flows through the inner tube of the double-walled pipe, nitrogen gas flows through the annular section of the outer tube, the nitrogen gas is supplied from a nitrogen gas storage tank and introduced from the inlet of the annular section of the outer tube, entering the annular section of the outer tube from the starting point of the double-walled pipe region and flowing toward the ending point of the double-walled pipe region, while the hydrogen gas flows toward the starting point of the double-walled pipe region, with the direction of flow of the nitrogen gas being opposite to the direction of flow of the hydrogen gas. A hydrogen gas sensor for detecting hydrogen leakage is installed in the piping on the outlet side of the outer annular section of the outer pipe, in the section where the nitrogen gas flows from the end of the double-pipe region to the outlet of the outer annular section. A hydrogen gas leak detection system from a high-pressure hydrogen gas pipeline, characterized in that the pressure of nitrogen gas in the annular portion of the outer pipe is adjusted to maintain a state where it is lower than the pressure of hydrogen gas in the inner pipe and higher than atmospheric pressure. 2. The system includes a pressure sensor for detecting the pressure in the annular portion of the outer tube, The pressure detected by the pressure sensor and the atmospheric pressure in the gas safety area are detected, The relationship between the pressure of the hydrogen gas (P1), the pressure of the nitrogen gas (P2), and the atmospheric pressure (P3) is (P1)>(P2)>(P3) The hydrogen gas leak detection system from high-pressure hydrogen gas piping according to claim 1, characterized in that the discharge pressure of the exhaust fan is adjusted to achieve the above. 3. A hydrogen gas leak detection system from a high-pressure hydrogen gas piping according to claim 1, characterized by comprising: a liquefied hydrogen tank; an evaporator that evaporates the liquefied hydrogen supplied from the liquefied hydrogen tank to obtain hydrogen gas; and a gas compressor that compresses the hydrogen gas to generate high-pressure hydrogen gas. 4. A hydrogen gas leak detection system from a high-pressure hydrogen gas pipeline according to claim 1, characterized by comprising a liquefied hydrogen tank, a pump for pressurizing the liquefied hydrogen supplied from the liquefied hydrogen tank, and an evaporator for evaporating the pressurized liquefied hydrogen to obtain hydrogen gas. [Effects of the Invention]

[0010] According to the present invention, even when hydrogen fuel is supplied to the marine engine room at high pressure injection (e.g., 30 MPa), a hydrogen leak detection system can be provided that prevents hydrogen leakage into the marine engine room and can quickly detect hydrogen leakage from the internal pipe. [Brief explanation of the drawing]

[0011] [Figure 1] A diagram illustrating an example of a hydrogen fuel supply method for marine engines such as diesel engines. [Figure 2] A diagram illustrating other examples of hydrogen fuel supply methods for marine engines such as diesel engines. [Figure 3] Cross-sectional view showing an example of a double-tube structure used in the present invention. [Modes for carrying out the invention]

[0012] Hereinafter, preferred embodiments of the present invention will be described based on the drawings. FIG. 1 is an example showing a method for supplying hydrogen fuel to a marine engine such as a diesel engine. 1 is a liquefied hydrogen tank, and 2 is an evaporator for evaporating the liquefied hydrogen sent from the liquefied hydrogen tank 1 to obtain hydrogen gas. The hydrogen gas obtained from the evaporator 2 is stored in the hydrogen gas buffer tank 3. When only boil-off gas is used for the supply from the liquefied hydrogen tank 1, the evaporator 2 may not be provided. The hydrogen gas is sent from the hydrogen gas buffer tank 3 to the gas compressor 4 through the hydrogen gas pipe.

[0013] The gas compressor 4 is preferably a multi-stage compressor. The multi-stage compressor is preferably composed of, for example, a front-stage compressor and a rear-stage compressor. The front-stage compressor is not particularly limited as long as it is configured to compress at an arbitrary number of stages of 1 to 3 stages. The number of compression stages is not limited to a maximum of 3 stages. In the front-stage compressor, for example, it is compressed in the range of 0.6 to 19 MPa. The rear-stage compressor is not particularly limited as long as it can be compressed to meet the required pressure of the marine engine. The liquefied hydrogen pressurized by the front-stage compressor may be further compressed by 1 or 2 stages by the rear-stage compressor 21. In the rear-stage compressor, for example, it may be compressed to exceed 30 MPa.

[0014] High-pressure hydrogen gas can also be obtained by a method different from the method shown in FIG. 1. For example, as shown in FIG. 2, the liquefied hydrogen sent from the liquefied hydrogen tank 1 is pressurized by the pressure pump 10. The liquefied hydrogen pressurized by the pressure pump 10 is evaporated by the evaporator 2 to obtain hydrogen gas. By doing so, hydrogen gas can be obtained as pressurized hydrogen gas without being sent from the hydrogen gas buffer tank 3 to the gas compressor 4 through the hydrogen gas pipe 101.

[0015] In the present invention, hydrogen gas at high pressure is generated by compressing it in this way and supplied to a marine engine via a hydrogen gas fuel pipe. If hydrogen gas leaks during the process of being transferred through the hydrogen gas pipe, since the pressure itself is very high, problems such as pipe rupture may occur, or there is a risk of reaching the explosion limit due to mixing with air. However, the present invention has the effect of eliminating the problems of pipe rupture and reaching the explosion limit, which is a specific problem of hydrogen gas.

[0016] Furthermore, in the present invention, in the gas safety agency area or in the vicinity thereof, hydrogen leakage can be detected promptly, and the risk caused by hydrogen leakage can be avoided.

[0017] The high-pressure hydrogen gas compressed by the gas compressor 4 passes through a double-pipe area of hydrogen gas and nitrogen gas, especially at the location where it enters the gas safety agency area 102, before being supplied to the marine engine 103 as shown in FIG. 3. In the present invention, hydrogen leakage is detected promptly at the stage when it enters the double-pipe area.

[0018] In this aspect, as shown in FIG. 3, the starting point of the double-pipe area 100 is near part A of the fuel control unit 103A provided in the marine engine 103 at least within the gas safety agency area 102, and the ending point is at part B at the boundary point of the gas safety agency area 102 or in its vicinity.

[0019] Therefore, in this aspect, a double-pipe is formed from part A to part B, and it may be extended to part C on the more upstream side than part B. Furthermore, it does not exclude the extension of the double-pipe area even further before part C.

[0020] In this aspect, high-pressure hydrogen gas flows through the inner pipe 101 of the double-pipe area 100, and nitrogen gas flows through the outer pipe annular part 104. The hydrogen gas flowing through the inner tube 101 of the double-walled pipe is controlled by a fuel control unit 103A located inside the marine engine 103. When hydrogen gas is no longer used as fuel, a purge unit 103B located inside the marine engine 103 removes the hydrogen present in the inner tube 101 by introducing nitrogen gas D into it, in order to prevent hydrogen from accumulating in the gas safety engine area 102.

[0021] The nitrogen gas flowing through the outer tube ring section 104 can be nitrogen gas stored in a nitrogen gas storage tank (not shown). Alternatively, nitrogen gas extracted from the atmosphere by a nitrogen gas generator (not shown) can be stored in the nitrogen gas storage tank.

[0022] An exhaust fan 105 is provided at the outlet 104A of the outer tube ring section 104, and nitrogen gas is discharged from inside the outer tube ring section 104 by the exhaust fan 105.

[0023] The exhaust fan 105 adjusts the pressure of the nitrogen gas flowing through the outer annular section 104 so that it remains lower than the pressure of the hydrogen gas in the inner tube 101, while also remaining higher than atmospheric pressure.

[0024] The nitrogen gas storage tank holds nitrogen gas at a pressure higher than atmospheric pressure, and the discharge flow rate from the nitrogen gas storage tank can be adjusted by adjusting the pressure regulator. Therefore, when the flow rate of the exhaust fan 105 is kept constant, the nitrogen in the outer tube ring section 104 can be maintained at a pressure higher than atmospheric pressure by adjusting the pressure regulator in the nitrogen gas storage tank.

[0025] Furthermore, the pressure of the nitrogen gas (P2) detected by the pressure sensor 107 that detects the pressure of the outer tube ring section 104 can be used to adjust the discharge pressure of the exhaust fan 105 so that, for example, the relationship between the atmospheric pressure (P3) in the gas safety agency area and the hydrogen gas pressure (P1) is (P1) > (P2) > (P3).

[0026] The hydrogen gas pressure in inner pipe 101 is 1 MPa or higher, and can be changed according to the pressure requirements of the marine engine, sometimes reaching high pressures such as 30 MPa.

[0027] In this case, the pressure of the nitrogen gas flowing through the outer annular section 104 is adjusted to be lower than the pressure of the hydrogen gas flowing through the inner tube 101. Furthermore, the pressure of the nitrogen gas flowing inside the outer tube ring section 104 only needs to be higher than atmospheric pressure (0.1 MPa), so it can be adjusted to, for example, 0.2 MPa to 0.5 MPa.

[0028] In this embodiment, the nitrogen gas storage tank holds nitrogen gas at a pressure higher than atmospheric pressure, and the discharge flow rate from the nitrogen gas storage tank can be adjusted by adjusting the pressure regulator. Therefore, by controlling the constant flow rate of the exhaust fan, the nitrogen in the outer tube ring section 104 can be maintained at a level higher than atmospheric pressure without controlling the exhaust fan based on the pressure sensor 107. Furthermore, to ensure greater safety, the pressure of the nitrogen gas flowing through the outer tube ring section 104 can be detected by the pressure sensor 107, and the airflow rate and discharge pressure of the exhaust fan 105 can be adjusted or controlled via the control unit 108 based on this.

[0029] The strength of the inner and outer pipes of hydrogen gas piping should preferably be able to withstand the pressure of the hydrogen and nitrogen gases flowing through it. Furthermore, fittings such as flanges and elbows, as well as instruments associated with these pipes, should also preferably have a specified level of pressure resistance.

[0030] A hydrogen gas sensor 106 is installed on the outlet side piping of the outer annular section 104 leading to the exhaust fan 105. The hydrogen gas sensor 106 detects hydrogen leakage. Preferably, the control unit 108 has a function to notify the ship's control room (not shown) that a hydrogen leak has occurred when the hydrogen gas sensor 106 detects it.

[0031] In this invention, measures to prevent hydrogen gas leakage are extremely important for the safety of the system, and it is preferable to keep the nitrogen gas in the outer tube ring section 104 flowing at all times, both for detecting hydrogen gas and for discharging it to the outside.

[0032] Since it is desirable to detect hydrogen gas leaks as quickly as possible, it is preferable to keep the fluid (nitrogen) in the annular section flowing continuously and install the hydrogen gas sensor 106 at its outlet to quickly detect hydrogen leaks.

[0033] Furthermore, it is desirable that the nitrogen flowing through the annular section does not contain air, and that the pressure in the annular section be kept higher than atmospheric pressure so that air from the atmosphere does not enter the outer annular section 104. In this manner, it is preferable to adjust or control the airflow and discharge pressure of the exhaust fan 105.

[0034] In this invention, the gas compressor 4 compresses the gas to a high pressure of, for example, 30 MPa. Since it is undesirable for this pressure to fluctuate, an accumulator 5 can be provided to suppress pressure fluctuations as needed. [Explanation of Symbols]

[0035] 1. Liquefied hydrogen tank 10. Pressure pump 2 Evaporator 3. Hydrogen gas buffer tank 4 Gas compressor 100 double pipe area 101 Inner tube 102 Gas Safety Agency Area 103 Marine Engines 103A Fuel Control Unit 103B Purge Unit 104 Outer tube annular part 104A Exit 105 Exhaust fan 106 Hydrogen gas sensor 107 Pressure Sensor 108 Control Unit

Claims

1. A hydrogen gas leak detection system from a high-pressure hydrogen gas pipeline that supplies high-pressure hydrogen gas fuel to a marine engine, wherein the hydrogen gas fuel pipeline located within the gas safety engine area is constructed as a double-walled pipe, The starting point of the double-pipe region is near a fuel control unit installed in a marine engine within the gas safety engine area, and the ending point of the double-pipe region is the boundary point of the gas safety engine area or its vicinity. The structure is such that high-pressure hydrogen gas flows through the inner tube of the double-walled pipe, nitrogen gas flows through the annular section of the outer tube, the nitrogen gas is supplied from a nitrogen gas storage tank and introduced from the inlet of the annular section of the outer tube, entering the annular section of the outer tube from the starting point of the double-walled pipe region and flowing toward the ending point of the double-walled pipe region, while the hydrogen gas flows toward the starting point of the double-walled pipe region, with the direction of flow of the nitrogen gas being opposite to the direction of flow of the hydrogen gas. A hydrogen gas sensor for detecting hydrogen leakage is installed in the piping on the outlet side of the outer annular section of the outer pipe, in the section where the nitrogen gas flows from the end of the double-pipe region to the outlet of the outer annular section. A hydrogen gas leak detection system from a high-pressure hydrogen gas pipeline, characterized in that the pressure of nitrogen gas in the annular portion of the outer pipe is adjusted to maintain a state where it is lower than the pressure of hydrogen gas in the inner pipe and higher than atmospheric pressure.

2. The system includes a pressure sensor for detecting the pressure in the annular portion of the outer tube, The pressure detected by the pressure sensor and the atmospheric pressure in the gas safety area are detected, The relationship between the pressure of the hydrogen gas (P1), the pressure of the nitrogen gas (P2), and the atmospheric pressure (P3) is (P1) > (P2) > (P3) The hydrogen gas leak detection system from high-pressure hydrogen gas piping according to claim 1, characterized in that the discharge pressure of the exhaust fan is adjusted to such a state.

3. A hydrogen gas leak detection system from a high-pressure hydrogen gas pipeline according to claim 1, comprising a liquefied hydrogen tank, an evaporator that evaporates the liquefied hydrogen supplied from the liquefied hydrogen tank to obtain hydrogen gas, and a gas compressor that compresses the hydrogen gas to generate high-pressure hydrogen gas.

4. A hydrogen gas leak detection system from a high-pressure hydrogen gas pipeline according to claim 1, characterized by comprising a liquefied hydrogen tank, a pump for pressurizing the liquefied hydrogen supplied from the liquefied hydrogen tank, and an evaporator for evaporating the pressurized liquefied hydrogen to obtain hydrogen gas.

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