Hydrogen gas leakage detection device and hydrogen gas leakage detection method

Abstract

To provide a hydrogen gas leakage detection device and a leakage detection method that can easily detect hydrogen gas leakage from flanges of piping in an orifice assembly by using an orifice as a flowmeter capable of measuring a hydrogen gas flow rate under a high-pressure environment.SOLUTION: A hydrogen gas leakage detection device includes a first flange 302 in upstream-side piping of hydrogen gas piping with a predetermined diameter and a second flange 303 in downstream-side piping. An orifice plate 304 is clamped between the opposing first flange 302 and second flange 303. The device includes an orifice flowmeter unit 30 that measures a gas flow rate by measuring gas pressure on the upstream side and downstream side of the orifice plate 304. The device includes a leak port 307 that guides hydrogen gas leaking from between the first flange 302 and the second flange 303 to the outside. The device includes a hydrogen gas sensor 310 that detects the hydrogen gas guided from the leak port 307.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for detecting leakage from a flow meter, and more particularly, to a hydrogen gas leakage detection device and a leakage detection method for detecting leakage of hydrogen gas in the process of supplying hydrogen fuel to a marine engine (diesel engine).

Background Art

[0002] In Patent Document 1, hydrogen gas stored in a gas tank is stored under compression at 100 MPa. However, when it is supplied to a hydrogen supply pipeline, for safety reasons, the hydrogen gas is decompressed to less than 1 MPa and supplied. Even when the supply pipe of hydrogen gas sets the internal pressure to a low pressure of 0.2 MPa and uses a pipe thinner than a general hydrogen supply pipe, it is possible to transfer a sufficient amount of hydrogen gas required for consumption by a hydrogen-consuming device, and the flow rate at each location is measured, and leakage of hydrogen gas is detected from the inconsistency of the total.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the technique of Patent Document 1 has a problem that there is no disclosure of a device capable of measuring the flow rate of hydrogen gas in a high-pressure environment, that is, there is no flow meter approved by the High-Pressure Gas Safety Act. Furthermore, when measuring the flow rate using an orifice, there is a problem that there is no method for grasping the leakage even if leakage of hydrogen gas occurs inside the flow meter.

[0005] Therefore, an object of the present invention is to provide a hydrogen gas leakage detection device and a leakage detection method that can easily grasp the leakage of hydrogen gas from the flange of a pipe in an orifice assembly using an orifice as a flow meter capable of measuring the flow rate of hydrogen gas under a high-pressure environment. Another object of the present invention will become apparent from the following description.

Means for Solving the Problems

[0006] The above problems are solved by the following inventions.

[0007] 1. A first flange is provided on the upstream pipe of a hydrogen gas pipe with a predetermined diameter, and a second flange is provided on the downstream pipe. An orifice plate is sandwiched between the opposed first flange and the second flange, and an orifice flow meter unit for measuring the gas flow rate by measuring the gas pressures on the upstream side and the downstream side of the orifice plate is provided. A leak port is provided to guide hydrogen gas leaking from between the first flange and the second flange to the outside. A hydrogen gas leakage detection device, characterized by comprising a hydrogen gas sensor for detecting hydrogen gas guided from the leak port. 2. A first reducer unit is provided upstream of the orifice flow meter unit to expand a pipe with a smaller diameter than the hydrogen gas pipe to a pipe with the same diameter as the hydrogen gas pipe. And a second reducer unit is provided downstream of the orifice flow meter unit to reduce a pipe with the same diameter as the hydrogen gas pipe to a pipe with a smaller diameter than the hydrogen gas pipe. The orifice flow meter unit, the first reducer unit, and the second reducer unit constitute an orifice assembly. The first reducer unit and the second reducer unit are flange-connected, and are provided with a leak port for guiding hydrogen gas leaking from the opposing flanges to the outside, and a hydrogen gas sensor for detecting hydrogen gas guided from the leak port. The hydrogen gas leakage detection device according to item 1 above, characterized by this. 3. It is equipped with a hydrogen gas buffer tank for storing hydrogen gas, and is equipped with a gas compressor for compressing and increasing the pressure of hydrogen gas from the hydrogen gas buffer tank to the orifice assembly. The hydrogen gas leakage detection device according to item 2 above, characterized in that the hydrogen gas pipe is supplied with high-pressure hydrogen gas. 4. It is equipped with a tank for storing liquid hydrogen, a liquid hydrogen pump for compressing and increasing the pressure of liquid hydrogen, a vaporizer for vaporizing the liquid hydrogen pressurized by the liquid hydrogen pump, and the hydrogen gas pipe is supplied with high-pressure hydrogen gas vaporized by the vaporizer. The hydrogen gas leakage detection device according to item 2 above. 5. The hydrogen gas pipe is equipped with an orifice flow meter unit, and a hydrogen gas leakage detection method characterized by introducing the hydrogen gas leaking from the orifice flow meter unit to a hydrogen gas sensor through a leak port to detect the hydrogen gas. 6. The upstream pipe of the orifice flow meter is equipped with a first flange, and the downstream pipe is equipped with a second flange, and the hydrogen gas leakage detection method according to item 5 above, characterized in that the hydrogen gas leaking from between the opposed first flange and second flange is introduced to a hydrogen gas sensor through a leak port for detecting the hydrogen gas.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a hydrogen gas leakage detection device and a leakage detection method that can easily grasp the leakage of hydrogen gas from the flange of the pipe in the orifice assembly by using an orifice as a flow meter capable of measuring the flow rate of hydrogen gas in a high-pressure environment.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described.

[0011] FIG. 1 is a diagram showing a method for supplying hydrogen fuel to a marine engine (for example, a diesel engine), FIG. 2 is a cross-sectional view showing an example of a hydrogen gas leakage detection device according to the present invention, and FIG. 3 is a cross-sectional view of a main part showing an example of an orifice flowmeter unit according to the present invention.

[0012] In the present invention, for example, hydrogen fuel supplied to a marine engine such as a diesel engine is supplied as high-pressure hydrogen gas. High-pressure hydrogen gas can be obtained from liquid hydrogen, and the following three methods can be mentioned for the process. The first method includes evaporating the liquefied hydrogen stored in a liquefied hydrogen tank in an evaporator without increasing the pressure to raise the temperature to obtain hydrogen gas, storing the hydrogen gas in a hydrogen gas buffer tank, and compressing it using a gas compressor to obtain high-pressure hydrogen gas. The step of compressing hydrogen gas by a gas compressor to increase the pressure may be performed from the hydrogen gas buffer tank to the orifice assembly. The second method includes obtaining high-pressure liquid hydrogen by a liquid hydrogen pump that compresses and increases the pressure of the liquefied hydrogen stored in a liquefied hydrogen tank. Next, a method of vaporizing it in a vaporizer regardless of the temperature to obtain high-pressure hydrogen gas can be mentioned. The third method includes obtaining boil-off gas generated from the liquefied hydrogen in a liquefied hydrogen tank without passing through an evaporator, storing it in a hydrogen gas buffer tank, and compressing it using a gas compressor to obtain high-pressure hydrogen gas.

[0013] Figure 1 shows the first method. In Figure 1, reference numeral 1 denotes a hydrogen gas buffer tank for storing hydrogen gas. In this configuration, hydrogen gas is sent to the hydrogen gas buffer tank 1 via an evaporator (not shown) that evaporates liquefied hydrogen sent from a liquefied hydrogen tank (not shown) to obtain hydrogen gas. The hydrogen gas is sent from the hydrogen gas buffer tank 1 to the gas compressor 2 via the hydrogen gas pipe 10. The gas compressor 2 preferably employs a multi-stage compression method. In this embodiment, it is composed of a front-stage compressor 20 and a rear-stage compressor 21.

[0014] The front-stage compressor 20 is not particularly limited, and a configuration that compresses in any number of stages, for example, 1 to 3 stages, can be adopted. The number of compression stages is not limited to a maximum of 3 stages. In the front-stage compressor 20, for example, it is compressed in the range of 0.6 to 19 MPa.

[0015] The rear-stage compressor 21 is not particularly limited as long as it can compress to meet the required pressure of a marine engine or an internal combustion engine. The rear-stage compressor 21 may further compress in 1 or 2 stages. In the rear-stage compressor 21, for example, it may be compressed to exceed 30 MPa.

[0016] The high-pressure hydrogen gas compressed by the gas compressor 2 is sent to the orifice assembly 3.

[0017] As shown in FIGS. 2 and 3, the orifice assembly 3 is composed of an orifice flowmeter unit 30, a first reducer unit 31, and a second reducer unit 32.

[0018] The first reducer unit 31 includes a reducer that expands a pipe having a smaller diameter than a hydrogen gas pipe of a predetermined diameter on the upstream side of the orifice flowmeter unit 30 to a pipe having the same diameter as the hydrogen gas pipe. The second reducer unit 32 includes a reducer that reduces a pipe having the same diameter as a hydrogen gas pipe of a predetermined diameter to a pipe having a smaller diameter than the hydrogen gas pipe.

[0019] In the present invention, the reason why the orifice assembly 3 includes the orifice flowmeter unit 30, the first reducer unit 31, and the second reducer unit 32 is that they are flange connections, and there is a possibility of hydrogen leakage from the flanges. Therefore, it is preferable that leak ports for detecting hydrogen leaking from the flanges are provided on those flanges.

[0020] Based on FIG. 3, the orifice flowmeter unit 30 will be described. At the tip of each of the upstream pipe 300 and the downstream pipe 301 of the hydrogen gas pipe, a first flange 302 and a second flange 303 are provided. The method of fixing the flange to the tip of the pipe is preferably performed by welding.

[0021] In order to improve the strength, the hydrogen gas pipe of the present embodiment may be configured as a double pipe with a protective pipe provided on the outer periphery. Furthermore, it can not only improve the strength but also function as a protective pipe for preventing leaked hydrogen gas from the inner pipe from being exposed to the atmosphere.

[0022] The orifice plate 304 is mounted between the flange 302 and the flange 303. The thickness and the hole diameter of the orifice are not particularly limited as long as it has a strength that can withstand high pressure.

[0023] Pressure detection pipes 305 and 306 are respectively mounted on the flanges 302 and 303. The method of mounting the pressure detection pipes 305 and 306 on the flanges 302 and 303 is not particularly limited. It is preferable to select a detection pipe made of a material that can withstand gas pressure, and it is preferable to adopt a seal structure without gas leakage. Pressure gauges 305A and 306A are provided on the tip sides of the pressure detection pipes 305 and 306. The pressure gauges 305A and 306A are connected to a control room (not shown) so that predetermined data can be sent.

[0024] A leak port 307 is formed between the orifice plate 304 and the flange 302 to guide hydrogen gas to the outside in case hydrogen gas leaks. This enables immediate detection of hydrogen gas leakage from the orifice flowmeter unit 30. The flange where the leak port 307 is formed is not limited to the flange 302 and may be the flange 303.

[0025] In this embodiment, the tip of the leak port 307 opens at the end face of the flange 302, and it is preferable that the flange 303 is formed with an opening 308 for guiding the tip of the leak port 307. The opening 308 is formed in a circular tube shape, and a part of the circular tube is opened by the tip of the leak port 307. Even if the hydrogen gas leaking from the flange leaks into any part of the opening 308, it is formed so as to be easily guided to the leak port 307. This facilitates the guidance to the leak port 307 and enables immediate detection of the leakage.

[0026] As shown in FIG. 3, it is preferable that seal members 309A, 309B, and 309C are provided above and below (upper periphery, lower periphery) in the radial direction of the tip opening of the leak port 307. The seal member 309A seals between the flange 302 and the orifice plate 304, and the seal member 309B seals between the flange 303 and the orifice plate 304. The seal member 309C is provided on the outer peripheral side of the leak port 307 and seals between the flanges 302 and 303. This is preferable from the viewpoint of reliably preventing hydrogen gas leakage between the flanges 302 and 303. As the seal members 309A, 309B, and 309C, an O-ring or the like is used. The material is appropriately determined in consideration of the gas pressure.

[0027] A hydrogen gas sensor 310 is provided at the tip of the leak port 307, and it can detect the leaked hydrogen.

[0028] To measure the flow rate of hydrogen gas using the orifice plate 304, the pressures of the hydrogen gas on both sides of the orifice plate 304 are measured using pressure gauges 305A and 306A.

[0029] The pressure of the hydrogen gas on the inlet side of the orifice plate 304 is high, but the pressure of the hydrogen gas on the outlet side of the orifice plate 304 decreases due to the pressure loss. Due to this pressure difference, the flow rate can be measured according to a predetermined formula.

[0030] Hereinafter, a method for measuring the flow rate using the orifice flow meter unit 30 will be briefly described. As shown in FIG. 3, when the flow rate Q of hydrogen gas with density ρ is passed through the orifice plate, the cross-sectional area A1 (inner diameter D of the pipe), flow velocity v1, and pressure P1 before throttling are set, and the cross-sectional area A2 (inner diameter d of the orifice), flow velocity v2, and pressure P2 after throttling are set. The flow rate Q (cross-sectional area × flow velocity) is obtained by the following formula (Equation 1). Thereby, it becomes possible to accurately measure the flow rate under high pressure. By this flow rate measurement, the supply amount with respect to the required amount of the internal combustion engine can be measured.

Equation

[0031] Next, the piping connection and hydrogen leakage detection method by the first reducer unit 31 that constitutes the orifice assembly 3 will be described.

[0032] The first reducer unit 31 is provided with a flange 312 and a flange 313 at the tips of an upstream pipe 311 having a smaller diameter than the hydrogen gas pipe and a downstream pipe (the upstream pipe of the orifice flow meter unit) 300 having the same diameter, respectively. The method of fixing the flange to the tip of the pipe is preferably performed by welding.

[0033] A leak port 314 for detecting hydrogen gas leakage between the two flanges 312 and 313 is provided. In this embodiment, the leak port 314 is provided in the flange 313, but it is not particularly limited and may be provided in the flange 312. A hydrogen gas sensor (not shown) is provided at the tip of the leak port 314.

[0034] Next, the piping connection and hydrogen leakage detection method by the second reducer unit 32 that constitutes the orifice assembly 3 will be described.

[0035] At the tip of each of the upstream pipe (downstream pipe of the orifice flowmeter unit 30) 301 having the same diameter as the hydrogen gas pipe and the downstream pipe 321 having a smaller diameter in the second reducer unit 32, a flange 322 and a flange 323 are provided. The method of fixing the flange to the tip of the pipe is preferably performed by welding.

[0036] A leak port 324 for detecting hydrogen gas leakage from between the two flanges 322 and 323 is provided. In this embodiment, the leak port 324 is provided in the flange 322, but there is no particular limitation, and it may be provided in the flange 323. A hydrogen gas sensor (not shown) is provided at the tip of the leak port 324.

[0037] Although the embodiments of the present invention have been described above, the present invention is not limited thereto, and a clamp 33 may be provided in the front stage of the first reducer unit 31, and a clamp 34 may also be provided in the rear stage of the second reducer unit 32.

[0038] In order to prevent hydrogen gas leakage by maintaining all the hydrogen gas pipes 10 of the orifice flowmeter unit 30, the first reducer unit 31, and the second reducer unit 32 horizontally, as shown in FIG. 2, a suspension member 35 that can be supported at a certain height from above, and support members 36 and 37 that support from below are provided. Thereby, breakage of the welded portion between the pipes can be prevented, and the horizontal state can be maintained. In this embodiment, in order to surely maintain the horizontal to prevent hydrogen gas leakage, clamps 33 and 34 are provided on both sides of each of the first reducer unit 31 and the second reducer unit 32.

Explanation of Reference Numerals

[0039] 1 Hydrogen gas buffer tank 10 Hydrogen gas pipe 2 Gas compressor 20 Low-pressure side compressor 21 High-pressure side compressor 3 Orifice assembly 30 Orifice flowmeter unit 300 Upstream piping 301 Downstream piping 302 Flange 303 Flange 304 Orifice plate 305, 306 Pressure detection tubes 305A, 306A Pressure gauges 307 Leak port 308 Opening 309A, 309B, 309C Sealing members 310 Hydrogen gas sensor 31 First reducer unit 311 Upstream piping 312, 313 Flanges 314 Leak port 32 Second reducer unit 321 Downstream piping 322, 323 Flanges 324 Leak port 33, 34 Clamps 35 Hanging member 36, 37 Support members

Claims

1. A first flange is provided on the upstream pipe of a hydrogen gas pipe with a specified diameter, and a second flange is provided on the downstream pipe. An orifice plate is clamped between the opposed first and second flanges, and an orifice flow meter unit for measuring the gas flow rate by measuring the gas pressures on the upstream and downstream sides of the orifice plate is provided. A leak port is provided for guiding hydrogen gas leaking from between the first and second flanges to the outside. A hydrogen gas leak detection device, comprising a hydrogen gas sensor for detecting the hydrogen gas guided from the leak port.

2. On the upstream side of the orifice flow meter unit, a first reducer unit for expanding a pipe having a smaller diameter than the hydrogen gas pipe to a pipe having the same diameter as the hydrogen gas pipe is provided. On the downstream side of the orifice flow meter unit, a second reducer unit for reducing a pipe having the same diameter as the hydrogen gas pipe to a pipe having a smaller diameter than the hydrogen gas pipe is provided. The orifice flow meter unit, the first reducer unit, and the second reducer unit constitute an orifice assembly. The first reducer unit and the second reducer unit are flange-connected, and are provided with a leak port for guiding hydrogen gas leaking from the opposing flanges to the outside, and a hydrogen gas sensor for detecting the hydrogen gas guided from the leak port. The hydrogen gas leak detection device according to Claim 1, characterized in that.

3. A hydrogen gas buffer tank for storing hydrogen gas is provided. A gas compressor for compressing hydrogen gas to a high pressure is provided from the hydrogen gas buffer tank to the orifice assembly. The hydrogen gas leak detection device according to Claim 2, characterized in that the high-pressure hydrogen gas is supplied to the hydrogen gas pipe.

4. A tank for storing liquid hydrogen is provided, a liquid hydrogen pump for compressing liquid hydrogen to a high pressure is provided, a vaporizer for vaporizing the liquid hydrogen pressurized by the liquid hydrogen pump is provided, and the high-pressure hydrogen gas vaporized by the vaporizer is supplied to the hydrogen gas pipe. The hydrogen gas leak detection device according to Claim 2, characterized in that.

5. An orifice flow meter unit is provided in the hydrogen gas pipe. A hydrogen gas leak detection method, characterized in that hydrogen gas leaking from the orifice flow meter unit is introduced into a hydrogen gas sensor via a leak port to detect the hydrogen gas.

6. The upstream pipe of the orifice flowmeter is provided with a first flange, and the downstream pipe is provided with a second flange. The hydrogen gas leakage detection method according to claim 5, characterized in that hydrogen gas leaking from between the opposed first flange and second flange is introduced into a hydrogen gas sensor through a leak port for guiding the hydrogen gas to the outside to detect the hydrogen gas.

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