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

Abstract

To provide a hydrogen leakage detection system capable of preventing leakage of hydrogen into a marine engine room and early detecting leakage of hydrogen from an inner pipe even when hydrogen fuel supply to the marine engine room is high-pressure injection.SOLUTION: In this structure, high-pressure hydrogen gas flows in an inner pipe 101 of a double pipe, and nitrogen gas flows in an outer pipe annular part 104. An outlet of the outer pipe annular part 104 is connected to an exhaust fan 105, and pressure of the nitrogen gas in the outer pipe annular part 104 is regulated by the exhaust fan 105 so as to maintain a state lower than pressure of hydrogen gas in the inner pipe 101 and maintain a state higher than atmospheric pressure. A hydrogen gas sensor 106 for detecting leakage of hydrogen is installed in outlet side piping of the outer pipe annular part 104.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a hydrogen leakage detection system, and more particularly to a hydrogen leakage detection system capable of safely supplying hydrogen fuel to marine engines such as diesel engines.

Background Art

[0002] In Patent Document 1, a pipe for sending combustible gas to a marine boiler is made into a double pipe, and nitrogen is enclosed in the annular part at a pressure higher than that of the combustible gas in the inner pipe to prevent the combustible gas from leaking into the annular part, and a mechanism for monitoring the pressure in the annular part and issuing an alarm is reported.

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

[0004] Also, in Patent Document 2, nitrogen is passed through the annular part 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 part (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 even if the hydrogen fuel supply to the marine engine room is high-pressure injection (for example, 30 MPa), it prevents hydrogen leakage into the marine engine room and can quickly detect hydrogen leakage from the inner pipe. The object is to provide a hydrogen leakage detection system.

[0007] Other problems of the present invention will become apparent from the following description.

Means for Solving the Problems

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

[0009] 1. A hydrogen gas leakage detection system from a high-pressure hydrogen gas pipe, which is composed of a double pipe for the hydrogen gas fuel pipe that supplies high-pressure hydrogen gas fuel to a marine engine. Among them, the hydrogen gas fuel pipe located within the gas safety agency area, The inner pipe of the double pipe has high-pressure hydrogen gas flowing through it, and the outer pipe annular part has nitrogen gas flowing through it. The outlet of the outer pipe annular part is connected to an exhaust fan. The pressure of the nitrogen gas in the outer pipe annular part is adjusted by the exhaust fan so as to maintain a state where it is lower than the pressure of the hydrogen gas in the inner pipe and higher than the atmospheric pressure. A hydrogen gas leakage detection system from a high-pressure hydrogen gas pipe, characterized in that a hydrogen gas sensor for detecting hydrogen leakage is installed in the outlet side pipe of the outer pipe annular part. 2. It is equipped with a pressure sensor for detecting the pressure of the outer pipe annular part. Detect the pressure detected by the pressure sensor and the atmospheric pressure in the gas safety agency area. The relationship among the pressure (P1) of the hydrogen gas, the pressure (P2) of the nitrogen gas, and the atmospheric pressure (P3) is (P1) > (P2) > (P3) The hydrogen gas leakage detection system from the high-pressure hydrogen gas pipe according to item 1 above, characterized in that the discharge pressure of the exhaust fan is adjusted so that the above relationship is satisfied. 3. A hydrogen gas leakage detection system from a high-pressure hydrogen gas pipeline according to claim 1, comprising a liquefied hydrogen tank, an evaporator for evaporating the liquefied hydrogen sent from the liquefied hydrogen tank to obtain hydrogen gas, and a gas compressor for compressing the hydrogen gas to generate high-pressure hydrogen gas. 4. A hydrogen gas leakage detection system from a high-pressure hydrogen gas pipeline according to claim 1, comprising a liquefied hydrogen tank, a pump for pressurizing the liquefied hydrogen sent from the liquefied hydrogen tank, and an evaporator for evaporating the pressurized liquefied hydrogen to obtain hydrogen gas.

Advantages of the Invention

[0010] According to the present invention, even when the hydrogen fuel supply to the marine engine room is high-pressure injection (for example, 30 MPa), it is possible to provide a hydrogen leakage detection system that can prevent hydrogen leakage into the marine engine room and quickly detect hydrogen leakage from the inner pipe.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0012] Hereinafter, preferred embodiments of the present invention will be described with reference to 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. 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 from 1 to 3. 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 compress to meet the required pressure of the marine engine. The rear-stage compressor 21 may further compress by 1 or 2 stages. 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 pressurizing pump 10. The liquefied hydrogen pressurized by the pressurizing pump 10 is evaporated by the evaporator 2 to obtain hydrogen gas. By doing so, hydrogen gas can obtain 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 is compressed in this way to generate high-pressure hydrogen gas and is supplied to the marine engine through the hydrogen gas fuel pipe. In the process of being transferred through the hydrogen gas pipe, if hydrogen gas leaks, 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, in the present invention, there is an effect that can solve problems such as pipe rupture and reaching the explosion limit, which is a problem specific to hydrogen gas.

[0016] Furthermore, in the present invention, in the gas safety agency area and its vicinity, it can quickly detect hydrogen leakage and exert an effect of avoiding the danger caused by hydrogen leakage.

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

[0018] In this aspect, as shown in FIG. 3, the starting point of the double-pipe region 100 is near part A of the fuel control unit 103A provided in the marine engine 103 at least within the marine engine area 102, and the end point is part B at the boundary point of the marine engine area 102 or 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 region even further before part C.

[0020] In this aspect, high-pressure hydrogen gas flows through the inner pipe 101 of the double-pipe region 100, and nitrogen gas flows through the outer pipe annular part 104. The hydrogen gas flowing through the inner pipe 101 of the double pipe is controlled for the supply of hydrogen gas to the engine in the fuel control unit 103A provided in the marine engine 103. When hydrogen gas is no longer used as fuel, in order not to retain hydrogen in the marine engine area 102, the purge unit 103B provided in the marine engine 103 injects nitrogen gas D into the inner pipe 101 of the double pipe to remove the hydrogen existing in the inner pipe 101.

[0021] As the nitrogen gas flowing through the outer pipe annular part 104, nitrogen gas stored in a nitrogen gas storage tank (not shown) can be used. Also, 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 pipe annular part 104, and the nitrogen gas is discharged from the inside of the outer pipe annular part 104 by the exhaust fan 105.

[0023] The pressure of the nitrogen gas flowing inside the outer tube annular part 104 is adjusted by the exhaust fan 105 so as to maintain a state where it is lower than the pressure of the hydrogen gas in the inner tube 101 and a state where it is higher than the atmospheric pressure.

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

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

[0026] The pressure of the hydrogen gas in the inner tube 101 is 1 MPa or more, can be changed according to the required pressure of the marine engine, and can be a high pressure such as 30 MPa.

[0027] In this case, the pressure of the nitrogen gas flowing inside the outer tube annular part 104 is adjusted to be lower than the pressure of the hydrogen gas flowing in the inner tube 101. Also, regarding the relationship between the pressure of the nitrogen gas flowing inside the outer tube annular part 104 and the atmospheric pressure (0.1 MPa), it only needs to be higher than the atmospheric pressure, 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 the adjustment of the pressure regulator. Therefore, by controlling the constant flow rate of the exhaust fan, the nitrogen in the outer pipe annular portion 104 can be maintained at a state higher than atmospheric pressure without controlling the exhaust fan based on the pressure sensor 107. Further, in order to ensure higher safety, the pressure of the nitrogen gas flowing through the outer pipe annular portion 104 is detected by the pressure sensor 107, and based on this, the air volume and discharge pressure of the exhaust fan 105 can also be adjusted or controlled via the control unit 108.

[0029] Preferably, the strength of the hydrogen gas piping of the inner pipe and the outer pipe has pressure resistance against the pressure of the flowing hydrogen gas and nitrogen gas, and fittings such as flanges and elbows and instruments attached to these pipes also preferably have a predetermined pressure resistance.

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

[0031] In the present invention, measures against hydrogen gas leakage are extremely important for the safety of the system, and it is preferable to constantly circulate the nitrogen gas in the outer pipe annular portion 104 both for detecting hydrogen gas and for discharging it to the outside.

[0032] Since it is desirable to detect hydrogen gas leakage as early as possible, it is preferable to constantly circulate the fluid (nitrogen) in the annular portion and install the hydrogen gas sensor 106 at its outlet to detect hydrogen leakage at the earliest.

[0033] Furthermore, at this time, it is desirable that the nitrogen flowing through the annular portion does not contain air, and it is preferable to adjust or control the air volume and discharge pressure of the exhaust fan 105 so that the pressure in the annular portion is maintained higher than atmospheric pressure and air does not enter the outer pipe annular portion 104 from the atmosphere.

[0034] In the present invention, due to the compression of the gas compressor 4, the pressure becomes as high as, for example, 30 MPa. However, it is not desirable for this pressure to fluctuate, so an accumulator 5 for suppressing pressure fluctuations can be provided if necessary.

Explanation of Signs

[0035] 1 Liquid hydrogen tank 10 Pressure pump 2 Evaporator 3 Hydrogen gas buffer tank 4 Gas compressor 100 Double pipe region 101 Inner pipe 102 Gas safety mechanism area 103 Marine engine 103A Fuel control unit 103B Purge unit 104 Outer pipe annular portion 104A Outlet 105 Exhaust fan 106 Hydrogen gas sensor 107 Pressure sensor 108 Control unit

Claims

1. A hydrogen gas leakage detection system from a high-pressure hydrogen gas pipeline, which is composed of a double pipe for the hydrogen gas fuel pipeline supplying high-pressure hydrogen gas fuel to a marine engine and located within a gas safety agency area, wherein: High-pressure hydrogen gas flows through the inner pipe of the double pipe, and nitrogen gas flows through the outer pipe annular part, The outlet of the outer pipe annular part is connected to an exhaust fan, The pressure of the nitrogen gas in the outer pipe annular part is adjusted by the exhaust fan so as to maintain a state lower than the pressure of the hydrogen gas in the inner pipe and higher than the atmospheric pressure, A hydrogen gas sensor for detecting hydrogen leakage is installed in the outlet side pipe of the outer pipe annular part. A hydrogen gas leakage detection system from a high-pressure hydrogen gas pipeline is characterized by this.

2. Equipped with a pressure sensor for detecting the pressure of the outer pipe annular part, Detecting the pressure detected by the pressure sensor and the atmospheric pressure in the gas safety agency area, The relationship among 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 leakage detection system from a high-pressure hydrogen gas pipeline according to Claim 1, characterized in that the discharge pressure of the exhaust fan is adjusted so as to satisfy this.

3. The hydrogen gas leakage detection system from a high-pressure hydrogen gas pipeline according to Claim 1, characterized by comprising a liquefied hydrogen tank, an evaporator for evaporating the liquefied hydrogen sent from the liquefied hydrogen tank to obtain hydrogen gas, and a gas compressor for compressing the hydrogen gas to generate high-pressure hydrogen gas.

4. The hydrogen gas leakage 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 sent from the liquefied hydrogen tank, and an evaporator for evaporating the pressurized liquefied hydrogen to obtain hydrogen gas.

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