Safety control device and safety control method for a hydrogen pipeline system installed in an open space.

Abstract

To provide a safety control device for a hydrogen pipeline system that enables stable and safe operation. [Solution] The safety control device according to the present disclosure includes a determination unit that performs, at different time intervals, a first determination which determines whether or not there is a hydrogen leak in the first pipeline based on the relative relationship or temporal change of measured values ​​between the first supply-side pressure gauge, the first demand-side pressure gauge and the reference pressure gauge when the first supply-side shut-off valve and the first demand-side shut-off valve are in a closed state, and a second determination which determines whether or not there is a hydrogen leak in the second pipeline based on the relative relationship or temporal change of measured values ​​between the second supply-side pressure gauge, the second demand-side pressure gauge and the reference pressure gauge when the second supply-side shut-off valve and the second demand-side shut-off valve are in a closed state.

Description

Technical Field

[0001] The present disclosure relates to a safety control device for a hydrogen pipeline system provided in an atmospheric open space.

Background Art

[0002] Patent Document 1 discloses a hydrogen transportation system. According to this hydrogen transportation system, surplus power from distributed energy sources can be effectively utilized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a system such as that of Patent Document 1, stable and safe operation is desired.

[0005] The present disclosure has been made to solve the above problems. The object of the present disclosure is to provide a safety control device for a hydrogen pipeline system that can perform stable and safe operation.

Means for Solving the Problems

[0006] The safety control device for a hydrogen pipeline system according to this disclosure comprises: a first pipeline provided in an open space; a second pipeline provided in an open space; a first supply-side shutoff valve provided on the hydrogen supply side in the piping system including the first pipeline; a second supply-side shutoff valve provided on the hydrogen supply side in the piping system including the first pipeline; a first demand-side shutoff valve provided on the hydrogen demand side in the piping system including the first pipeline; a second demand-side shutoff valve provided on the hydrogen demand side in the piping system including the second pipeline; and the first pipeline A first supply-side pressure gauge provided on the hydrogen supply side downstream of the supply-side shut-off valve in a piping system including the inlet; a second supply-side pressure gauge provided on the hydrogen supply side downstream of the supply-side shut-off valve in a piping system including the second pipeline; a first demand-side pressure gauge provided on the hydrogen demand side upstream of the first demand-side shut-off valve in a piping system including the first pipeline; a second demand-side pressure gauge provided on the hydrogen demand side upstream of the second demand-side shut-off valve in a piping system including the second pipeline; and the first pipeline and the second pipeline. In a safety control device for a hydrogen pipeline system comprising a piping system and a reference pressure gauge provided on the hydrogen supply side upstream of the first supply-side shut-off valve and the second supply-side shut-off valve, the safety control device includes an acquisition unit that acquires the measured values ​​of the first supply-side pressure gauge, the second supply-side pressure gauge, the first demand-side pressure gauge, the second demand-side pressure gauge, and the reference pressure gauge for a predetermined time, and when the first supply-side shut-off valve and the first demand-side shut-off valve are in a closed state, the safety control device provides a safety control device based on the relative relationship or temporal change of the measured values ​​of the first supply-side pressure gauge, the first demand-side pressure gauge, and the reference pressure gauge. The system includes a determination unit that performs a first determination to determine whether or not there is a hydrogen leak in the first pipeline, and a second determination to determine whether or not there is a hydrogen leak in the second pipeline based on the relative relationship or temporal change of measured values ​​between the second supply-side pressure gauge, the second demand-side pressure gauge, and the reference pressure gauge, when the second supply-side shutoff valve and the second demand-side shutoff valve are in a closed state, at different time intervals; and a control unit that controls the first supply-side shutoff valve according to the first determination result by the determination unit and controls the second supply-side shutoff valve according to the second determination result by the determination unit.

[0007] The safety control method for a hydrogen pipeline system according to this disclosure comprises: a first pipeline provided in an open space; a second pipeline provided in an open space; a first supply-side shutoff valve provided on the hydrogen supply side in the piping system including the first pipeline; a second supply-side shutoff valve provided on the hydrogen supply side in the piping system including the second pipeline; a first demand-side shutoff valve provided on the hydrogen demand side in the piping system including the first pipeline; and a second demand-side shutoff valve provided on the hydrogen demand side in the piping system including the second pipeline. A safety control method for controlling a hydrogen pipeline system comprising: a first supply-side pressure gauge provided on the hydrogen supply side downstream of the first supply-side shutoff valve in a piping system including the first pipeline; a second supply-side pressure gauge provided on the hydrogen supply side downstream of the second supply-side shutoff valve in a piping system including the second pipeline; a first demand-side pressure gauge provided on the hydrogen demand side upstream of the first demand-side shutoff valve in a piping system including the first pipeline; a second demand-side pressure gauge provided on the hydrogen demand side upstream of the second demand-side shutoff valve in a piping system including the second pipeline; and a reference pressure gauge provided on the hydrogen supply side upstream of the first supply-side shutoff valve and the second supply-side shutoff valve in a piping system including the first pipeline and the second pipeline, wherein the second supply The process includes: keeping the side shut-off valve and the second demand-side shut-off valve in an open state, closing the first supply-side shut-off valve and the first demand-side shut-off valve, acquiring measured values ​​from the first supply-side pressure gauge, the first demand-side pressure gauge and the reference pressure gauge for a predetermined time, and performing a first determination to determine whether or not there is a hydrogen leak in the first pipeline based on the relative relationship or temporal change of the measured values; and keeping the first supply-side shut-off valve and the first demand-side shut-off valve in an open state, closing the second supply-side shut-off valve and the second demand-side shut-off valve, acquiring measured values ​​from the second supply-side pressure gauge, the second demand-side pressure gauge and the reference pressure gauge for a predetermined time, and performing a second determination to determine whether or not there is a hydrogen leak in the second pipeline at a time period different from the first determination, based on the relative relationship or temporal change of the measured values. [Effects of the Invention]

[0008] According to this disclosure, a stable and safe hydrogen pipeline system can be constructed. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example of the application of a safety control device for a hydrogen pipeline system in Embodiment 1. [Figure 2] This figure shows the amount of hydrogen in the hydrogen pipeline system in Embodiment 1. [Figure 3] This is a block diagram of the data processing unit as a safety control device for a hydrogen pipeline system in Embodiment 1. [Figure 4] This is a flowchart illustrating the leak test procedure using the safety control device for the hydrogen pipeline system in Embodiment 1. [Figure 5] This is a hardware configuration diagram of the data processing unit as a safety control device for a hydrogen pipeline system in Embodiment 1. [Modes for carrying out the invention]

[0010] Embodiments will be described with reference to the attached drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals. The explanation of such parts will be simplified or omitted as appropriate.

[0011] Embodiment 1. Figure 1 shows an example of the application of a safety control device for a hydrogen pipeline system in Embodiment 1.

[0012] The hydrogen pipeline system described herein is • Small diameter piping (e.g., 20A) • Relatively low-pressure operation (e.g., around 0.6 to 0.9 MPa) • Installation in an open space • Finite line pack volume (e.g., approximately 2.7 Nm³) 3) Based on these conditions, it is a piping system that, unlike typical high-pressure gas equipment, has a relatively limited amount of energy it can hold as a system.

[0013] Furthermore, 1. Monitoring of flow rate differences during operation 2. Diagnosis of pressure behavior after shutoff 3. Alternating diagnosis using dual pipelines By combining these elements, safety management can be achieved.

[0014] The following provides a detailed explanation of the security management methods for this disclosure.

[0015] In Figure 1, the hydrogen pipeline system comprises a first hydrogen demand facility, a second hydrogen demand facility, and a relay facility.

[0016] The hydrogen supply facility comprises a hydrogen supply source 1, supply piping 2, shut-off valve SH1, safety valve S1, electric shut-off valves M1 and M2, pressure gauges P1, P6 and P7, flow meters MFM1 and MFM2, supply-side control equipment 3, and wireless box 1.

[0017] Hydrogen supply source 1 has the function of generating hydrogen. The upstream side of supply piping 2 is connected to hydrogen supply source 1. The downstream side of supply piping 2 branches into two, forming a branch section.

[0018] The shut-off valve SH1 is located immediately after the hydrogen supply source 1 and on the upstream side of the supply piping 2. The shut-off valve SH1 is located at the boundary between the hydrogen supply source management and the hydrogen pipeline safety control management. The safety valve S1 is located immediately after the shut-off valve SH1 and on the upstream side of the supply piping 2. The safety valve S1 is located in an open space.

[0019] The electric shut-off valve M1 is installed on one side of the branch section as the first supply-side shut-off valve. The electric shut-off valve M2 is installed on the other side of the branch section as the second supply-side shut-off valve.

[0020] Pressure gauge P1 is installed as a reference pressure gauge in the supply piping 2 downstream of safety valve S1 and upstream of electric shut-off valves M1 and M2. Pressure gauge P6 is installed as a first supply-side pressure gauge downstream of electric shut-off valve M1 at one of the branching points. Pressure gauge P7 is installed as a second supply-side pressure gauge downstream of electric shut-off valve M2 at the other branching point.

[0021] Flow meter MFM1 is installed as a first supply-side flow meter between the electric shut-off valve M1 and the pressure gauge P6 at one end of the branching section. Flow meter MFM2 is installed as a second supply-side flow meter between the electric shut-off valve M2 and the pressure gauge P7 at the other end of the branching section.

[0022] The supply-side control device 3 includes at least a data processing unit 4. The data processing unit 4 has the function of wirelessly communicating with the electric shut-off valves M1 and M2, pressure gauges P1, P6 and P7, flow meters MFM1 and MFM2, and wireless box 1. The wireless box 1 is built into the supply-side control device 3. The wireless box 1 has the function of wireless communication.

[0023] The first hydrogen demand facility includes a first demand device 5, a first demand piping 6, a shut-off valve SH2, electric shut-off valves M3 and M4, pressure gauges P2 and P3, flow meters MFM3 and MFM4, a first demand side control device 7, and a wireless box 2.

[0024] The first demand device 5 is equipped with the function of operating using hydrogen as a power source. The upstream side of the first demand piping 6 forms a branch section where it splits into two. The downstream side of the first demand piping 6 forms a confluence section where the branch sections merge. The confluence section is connected to the first demand device 5.

[0025] The shut-off valve SH2 is installed at the junction. The shut-off valve SH2 is installed at the boundary between hydrogen demand management and hydrogen pipeline safety control management.

[0026] The electric shut-off valve M3 is installed on one side of the branch section as the second demand-side shut-off valve. The electric shut-off valve M4 is installed on the other side of the branch section as the first demand-side shut-off valve.

[0027] Pressure gauge P2 is installed as a second demand-side pressure gauge upstream of the electric shut-off valve M3 on one side of the branch section. Pressure gauge P3 is installed as a first demand-side pressure gauge upstream of the electric shut-off valve M4 on the other side of the branch section.

[0028] Flow meter MFM3 is installed as a second demand-side flow meter between the electric shut-off valve M3 and pressure gauge P2 at one end of the branching section. Flow meter MFM4 is installed as a first demand-side pressure gauge between the electric shut-off valve M4 and pressure gauge P3 at the other end of the branching section.

[0029] The first demand-side control device 7 includes at least a data processing unit. The data processing unit has the function of wirelessly communicating with the electric shut-off valves M3 and M4, pressure gauges P2 and P3, flow meters MFM3 and MFM4, and wireless box 2. Wireless box 2 is built into the first demand-side control device 7. Wireless box 2 has the function of wireless communication.

[0030] The second hydrogen demand facility includes a second demand equipment 8, a second demand piping 9, a shut-off valve SH3, electric shut-off valves M5 and M6, pressure gauges P4 and P5, flow meters MFM5 and MFM6, a second demand side control equipment 10, and a wireless box 3.

[0031] The second demand device 8 is equipped with the function of operating using hydrogen as a power source. The upstream side of the second demand piping 9 forms a branch section where it splits into two. The downstream side of the second demand piping 9 forms a confluence section where the branch sections merge. The confluence section is connected to the second demand device 8.

[0032] The shut-off valve SH3 is installed at the junction. The shut-off valve SH3 is installed at the boundary between hydrogen demand management and hydrogen pipeline safety control management.

[0033] The electric shut-off valve M5 is installed on one side of the branch section as the first demand-side shut-off valve. The electric shut-off valve M6 is installed on the other side of the branch section as the second demand-side shut-off valve.

[0034] Pressure gauge P4 is installed as a first demand-side pressure gauge upstream of the electric shut-off valve M5 on one side of the branch section. Pressure gauge P5 is installed as a second demand-side pressure gauge upstream of the electric shut-off valve M6 on the other side of the branch section.

[0035] Flow meter MFM5 is installed as a first demand-side flow meter between the electric shut-off valve M5 and the pressure gauge P4 at one end of the branching section. Flow meter MFM6 is installed as a second demand-side flow meter between the electric shut-off valve M6 and the pressure gauge P5 at the other end of the branching section.

[0036] The second demand-side control device 10 includes at least a data processing unit. The data processing unit has the function of wirelessly communicating with the electric shut-off valves M5 and M6, pressure gauges P4 and P5, flow meters MFM5 and MFM6, and wireless box 3. The wireless box 3 is built into the second demand-side control device 10. The wireless box 3 has the function of wireless communication.

[0037] The relay facility comprises a first pipeline 11, a second pipeline 12, relay box 1, and relay box 2.

[0038] The first pipeline 11 is installed in an open space. For example, the first pipeline 11 is erected on a column. The upstream side of the first pipeline 11 is connected to the downstream side of one of the branch sections in the supply pipe 2. The downstream side of the first pipeline 11 branches into two, forming a branch section. One of the branch sections is connected to the upstream side of one of the branch sections in the first demand pipe 6. The other branch section is connected to the upstream side of one of the branch sections in the second demand pipe 9.

[0039] The second pipeline 12 is installed in an open space. For example, the second pipeline 12 is erected on a column. The upstream side of the second pipeline 12 is connected to the downstream side of the other branch in the supply pipe 2. The downstream side of the second pipeline 12 branches into two, forming a branch section. One branch of the branch section is connected to the upstream side of the other branch in the first demand pipe 6. The other branch of the branch section is connected to the upstream side of the other branch in the second demand pipe 9.

[0040] Relay box 1 is located adjacent to the upstream side of the first pipeline 11 and the second pipeline 12. Relay box 1 is equipped with the function to communicate wirelessly with wireless box 1. Relay box 2 is located adjacent to the downstream side of the first pipeline 11 and the second pipeline 12. Relay box 2 is equipped with the function to communicate wirelessly with relay box 1, wireless box 2, and wireless box 3.

[0041] When the shut-off valve SH1 closes, hydrogen is not supplied to the first pipeline 11 and the second pipeline 12. In other words, hydrogen is not supplied to the first demand device 5 and the second demand device 8. This is effective when disconnecting the first demand device 5 and the second demand device 8 from the first pipeline 11 and the second pipeline 12.

[0042] When the shut-off valve SH2 closes, hydrogen is not supplied to the first demand device 5. This is effective when disconnecting the first demand device 5 from the first pipeline 11 and the second pipeline 12.

[0043] When the shut-off valve SH3 closes, hydrogen is not supplied to the second demand equipment 8. This is effective when disconnecting the second demand equipment 8 from the first pipeline 11 and the second pipeline 12.

[0044] Safety valve S1 is set so that the hydrogen supplied to the first pipeline 11 and the second pipeline 12 is 0.98 MPa or less. If safety valve S1 is open and the pressure of the hydrogen supplied from hydrogen source 1 is 1 MPa, then hydrogen above 0.98 MPa is released into the atmosphere by safety valve S1.

[0045] Pressure gauge P1 indicates the hydrogen pressure supplied from hydrogen source 1, not exceeding 0.98 MPa. For example, if the shut-off valve SH1 opens while the hydrogen pressure at hydrogen source 1 is set to 0.8 MPa, pressure gauge P1 will show 0.8 MPa. The value of P1 is sent to the data processing unit 4 of the supply-side control device 3.

[0046] Pressure gauge P6 indicates the pressure in the first pipeline 11. The value of P6 is sent to the data processing unit of the supply-side control device 3. Pressure gauge P7 indicates the pressure in the second pipeline 12. The value of P7 is sent to the data processing unit 4 of the supply-side control device 3.

[0047] Pressure gauge P2 continuously measures the pressure of hydrogen supplied from the second pipeline 12. The value of P2 is sent to the data processing unit 4 of the supply-side control device 3 via wireless box 2, relay box 2, relay box 1, and wireless box 1. Pressure gauge P3 continuously measures the pressure of hydrogen supplied from the first pipeline 11. The value of P3 is sent to the data processing unit 4 of the supply-side control device 3 via wireless box 2, relay box 2, relay box 1, and wireless box 1.

[0048] Pressure gauge P4 continuously measures the pressure of hydrogen supplied from the first pipeline 11. The value of P4 is sent to the data processing unit 4 of the supply-side control device 3 via wireless box 3, relay box 2, relay box 1, and wireless box 1. Pressure gauge P5 continuously measures the pressure of hydrogen supplied from the first pipeline 11. The value of P5 is sent to the data processing unit 4 of the supply-side control device 3 via wireless box 3, relay box 2, relay box 1, and wireless box 1.

[0049] The electric shut-off valve M1 opens and closes when a command arrives from the data processing unit 4 of the supply-side control device 3. The electric shut-off valve M2 opens and closes when a command arrives from the data processing unit 4 of the supply-side control device 3.

[0050] The electric shut-off valve M3 opens and closes when a command from the data processing unit 4 of the supply-side control device 3 arrives via wireless box 1, relay box 1, relay box 2, and wireless box 2. The electric shut-off valve M4 opens and closes when a command from the data processing unit 4 of the supply-side control device 3 arrives via wireless box 1, relay box 1, relay box 2, and wireless box 2.

[0051] The electric shut-off valve M5 opens and closes when a command from the data processing unit 4 of the supply-side control device 3 arrives via wireless box 1, relay box 1, relay box 2, and wireless box 3. The electric shut-off valve M6 opens and closes when a command from the data processing unit 4 of the supply-side control device 3 arrives via wireless box 1, relay box 1, relay box 2, and wireless box 3.

[0052] In other words, the opening and closing of each electric shut-off valve is centrally managed by commands from the data processing unit 4 of the supply-side control device 3. Each electric shut-off valve mechanically closes to cut off the hydrogen flow when all power is lost. Each electric shut-off valve is of paramount importance in ensuring safety within the hydrogen pipeline system configuration.

[0053] Flow meter MFM1 measures the amount of hydrogen supplied to flow through the first pipeline 11. The value from MFM1 is sent to the data processing unit 4 of the supply-side control device 3. Flow meter MFM2 measures the amount of hydrogen supplied to flow through the second pipeline 12. The value from MFM2 is sent to the data processing unit 4 of the supply-side control device 3.

[0054] Flow meter MFM3 measures the amount of hydrogen flowing from the second pipeline 12 to the first demand equipment 5. The value from MFM3 is sent to the data processing unit 4 of the supply-side control equipment 3 via wireless box 2, relay box 2, relay box 1, and wireless box 1. Flow meter MFM4 measures the amount of hydrogen flowing from the first pipeline 11 to the first demand equipment 5. The value from MFM4 is sent to the data processing unit 4 of the supply-side control equipment 3 via wireless box 2, relay box 2, relay box 1, and wireless box 1.

[0055] Flow meter MFM5 measures the amount of hydrogen flowing from the first pipeline 11 to the second demand equipment 8. The value from MFM5 is sent to the data processing unit 4 of the supply-side control equipment 3 via wireless box 3, relay box 2, relay box 1, and wireless box 1. Flow meter MFM6 measures the amount of hydrogen flowing from the second pipeline 12 to the second demand equipment 8. The value from MFM6 is sent to the data processing unit 4 of the supply-side control equipment 3 via wireless box 3, relay box 2, relay box 1, and wireless box 1.

[0056] In the supply-side control device 3, the data processing unit 4 controls the hydrogen pipeline as a whole. Specifically, the data processing unit 4 controls the opening and closing of each electric shut-off valve based on the measured values ​​from each pressure gauge and each flow meter.

[0057] Here, we will consider the amount of hydrogen in the pipeline using Figure 2. Figure 2 shows the amount of hydrogen in the hydrogen pipeline system in Embodiment 1.

[0058] Figure 2 shows the amount of hydrogen packed into a 1km pipeline of 20A flexible tube. At a pressure of 0.9MPa, the amount is 2.7Nm³. 3 It is filled with hydrogen. The amount of hydrogen is 7 Nm³. 3 This is less than half (approximately 38%) the amount compared to a hydrogen cylinder.

[0059] Specifically, the hydrogen cylinder is at 150 atmospheres. In a hydrogen cylinder with a diameter of 23 cm and a height of 138 cm, the pressure is 7 Nm. 3 There is hydrogen present. In contrast, the pipeline is at 9 atmospheres. The pressure in the pipeline is 6% of the pressure in the hydrogen cylinder. For example, in a pipeline with a diameter of 1.96 cm and a length of 1000 m, the pressure is 2.7 Nm. 3 Hydrogen exists.

[0060] Here, the volume of the hydrogen cylinder is as follows: 0.115 2 ×3.14 × 1.18 = 0.00573m 3

[0061] Dividing this value by the cross-sectional area of ​​the pipeline gives the length of the pipeline that has the same volume as the hydrogen cylinder. The resulting length is as follows: 0.0573 ÷ (0.0196 2 (×3.14) = 47.36m

[0062] The amount of water contained within this length is as follows: 47.36÷1000×2.7 = 0.128 Nm 3

[0063] Thus, in a pipeline of 47.36 m, which is the same volume as one hydrogen cylinder, 128 liters of hydrogen is trapped. That is, when comparing volumes, the amount of hydrogen in the pipeline is 1.8% of that in the hydrogen cylinder.

[0064] Furthermore, consider the leakage test of the pipeline. The premises are as follows. · A hydrogen pipeline made of a 20A flexible tube with an inner diameter of 19.6 mm is installed in an open-air space of 1 km. · The pipeline contains hydrogen at 0.9 MPa. · Both ends of the pipeline are closed. · The amount of hydrogen trapped in the pipeline is approximately 2.7 Nm 3 is. · A 0.1 mm hole opens at one point in the pipeline. · Hydrogen is gradually released into the atmosphere.

[0065] The process of the flow rate at this time is calculated. Also, the time it takes for the pressure in the pipeline to drop to 0.8 MPa, 0.7 MPa, etc. is calculated. Below, it is organized as an approximate calculation based on engineeringly reasonable assumptions. (It is not an exact solution, but a calculation for grasping the order of leakage behavior and safety evaluation.)

[0066] 1. Organization of Premises Pipeline Conditions Hole diameter: 0.1 mm Inner diameter: 19.6 mm → radius r = 9.8 mm Length: 1000 m Inner volume: V = πr 2 L = π(9.8×10 -3 )×1000 ≈ 0.302 m 3

[0067] Gas Conditions Gas: Hydrogen (H2) Initial pressure: 0.9 MPa (assuming absolute pressure is 1.0 MPa) Atmospheric pressure: 0.1 MPa Temperature: 20°C (293K) Specific heat ratio (adiabatic index): γ = 1.41 Gas constant (hydrogen): R = 4124 J / (kg·K) Initial gas volume: Approximately 2.7 Nm³ 3 Mass conversion: ρN=0.0899kg / Nm 3 →m0≈0.243Kg

[0068] 2. Leakage hole conditions Hole diameter: 0.1mm Hole area: A=π(0.05×10 -3 ) 2 ≈ 7.85 × 10 -9 m 2 Emission coefficient (assuming sharp edges): C d =0.7

[0069] 3. Determining the flow state (choke flow) Critical pressure ratio:

[0070]

number

[0071] Initial state:

[0072]

number

[0073] Completely choke flow (sonic flow) *Choke flow continues until the pressure drops to 0.19 MPa (abs).

[0074] 4. Mass flow rate formula for choke flow

[0075]

number

[0076] Putting the constants together:

[0077]

number

[0078] Therefore: m· = 0.7 × 7.85 × 10 -9 ×P×0.00055

[0079] 5. Initial leakage flow rate (0.9 MPa) P = 1.0 × 10 6 Pa m·0 = 3.0 × 10 -6 kg / s Volumetric flow rate (Nm 3 (Conversion)

[0080]

number

[0081] 6. Calculation of pressure drop time (choke flow region) Mass of gas inside the piping:

[0082]

number

[0083] Pressure and mass are proportional:

[0084]

number

[0085] Exponential decay: P(t)=P0exp(-t / τ) Time constant:

[0086]

number

[0087] 7. Time required for pressure to drop

[0088]

number

[0089] Pressure (abs) Elapsed time 0.9 → 0.8 MPa: Approximately 8.3 hours 0.9 → 0.7 MPa (approximately 18 hours) 0.9 → 0.6 MPa in approximately 29 hours 0.9 → 0.5 MPa (approximately 41 hours) 0.9→0.3MPa approximately 77 hours 0.9→0.19MPa approximately 108 hours (≒4.5 days) *The flow transitions to a non-choke flow below 0.19 MPa, and the pressure decreases even more slowly thereafter.

[0090] 8. Key Engineering Points Even a 0.1mm pinhole can cause a reduction in pressure over "days." • Initial leakage rate is very small (0.12 Nm³) 3 / h) • In the pipeline, sudden ruptures and instantaneous releases will not occur. In other words, leak detection could involve a combination of pressure monitoring and localized hydrogen sensors.

[0091] Next, we will calculate the case where the hole diameter is 1 mm. 1. Changes only (reposted) Leak hole Hole diameter: 1.0mm Radius: 0.5mm Pore ​​area: 100 times that of a 0.1 mm hole Emission coefficient: C d =0.7

[0092] 2. Leakage status (reconfirmation) Initial pressure: 0.9 MPa (abs 1.0 MPa) Atmospheric pressure: 0.1 MPa

[0093]

number

[0094] Complete choke flow (sonic flow): Choke flow continues up to abs 0.19 MPa.

[0095] 3.Initial leakage flow rate (1mm hole) Choke flow mass flow formula:

[0096]

number

[0097] Constant part (same as last time): 0.00055 Initial pressure: P = 1.0 MPa m·0 = 3.0 × 10 -4 kg / s Volumetric flow rate (Nm 3 Conversion): 0.1mm hole (0.12Nm 3 100 times ( / h)

[0098]

number

[0099] 4. Model of pressure drop Chalk flow is: Mass inside the pipe ∝ pressure Leakage mass flow rate ∝ pressure Therefore: P(t) = P0exp(-t / τ)

[0100] 5. Recalculation of the time constant The time constant is inversely proportional to the hole area: 0.1mm hole: τ≒2.6×105s≒72h 1.0mm hole (area 100):

[0101]

number

[0102] 6. Time required for pressure to drop

number

[0103] Pressure (abs) Elapsed time 0.9 → 0.8 MPa, approximately 5 minutes 0.9→0.7MPa approximately 11 minutes 0.9 → 0.6 MPa, approximately 18 minutes 0.9 → 0.5 MPa (approximately 25 minutes) 0.9→0.3MPa approximately 46 minutes 0.9→0.19MPa approximately 65 minutes (≒1.1 hours) * Decompression to the choke flow limit takes approximately 1 hour.

[0104] 7. Estimated time until full release Initial hydrogen content: 2.7 Nm³ 3 Initial flow rate: 12Nm 3 / h Considering exponential decay, it takes approximately 2 to 2.5 hours to reach near atmospheric pressure.

[0105] 8. Engineering and Safety Implications A. Qualitative changes in leakage behavior • 0.1mm hole: "Slow and steady, over days" • 1.0mm hole: Completely "short-term release, hourly" B. Jet • Supersonic jets are emitted from the outlet. • High-concentration hydrogen regions are formed in the initial few tens of centimeters to about 1 meter. However, the total amount is 2.7 Nm³. 3 And it is limited. C. Empirical and explanatory key points 1mm is a "damage hole," not a "pinhole." nevertheless • Not an explosive release • Pressure drops sharply within a few minutes to an hour. • Immediate detection possible through pressure monitoring

[0106] In this disclosure, the supply side and the demand side are connected by a first pipeline 11 and a second pipeline 12, and leakage is detected by shutting off one of the first pipeline 11 or the second pipeline 12 at a unit time and monitoring the pressure change in the pipeline for a certain period of time.

[0107] Next, we will explain a comparison table of leakage behavior for different hole diameters (0.1mm / 1mm / 5mm), a comparison of leakage rates with low-pressure city gas pipes, and the estimation of the distance to reach the flammable range (4 to 75%).

[0108] 1. Leakage behavior comparison table by hole diameter (0.1mm / 1mm / 5mm) premise ·Piping internal volume: 0.302m 3 Initial hydrogen content: 2.7 Nm³ 3 • Emission coefficient: C d =0.7 • Choke flow (from 0.19 MPa abs)

[0109] Item 0.1mm 1mm 5mm Pore ​​area ratio 1 100 2500 Initial leakage flow rate (Nm3 / h) 0.12 12 300 Time constant τ Approx. 72h Approx. 0.72h Approx. 0.029h 0.9 → 0.8 MPa 8.3h 5min 12s 0.9 → 0.7 MPa 18h 11min 25s 0.9 → 0.5 MPa 41h 25min 1min Chalk flow completed: Approximately 4.5 days, approximately 65 minutes, approximately 2.5 minutes Near atmospheric pressure, approximately 7 days, 2 to 2.5 hours, 5 to 6 minutes.

[0110] Therefore, • 0.1mm hole: Leakage over time • 1mm hole: Short-term anomaly (reliably detected by safety system) • 5mm hole: Immediate abnormality (sudden pressure drop) It can be said that...

[0111] 2. Comparison of leakage rates with low-pressure city gas pipes Comparison conditions • Pipeline: 0.9 MPa (gauge) • City gas low-pressure pipe: 3kPa (gauge) ·Same hole diameter (1mm) • A choke flow is possible with hydrogen alone.

[0112] Item: Pipeline, City gas low-pressure pipe Pipe pressure: 0.9 MPa / 0.003 MPa Outflow state: Supersonic choke flow, non-choke flow Leakage flow rate: approximately 12 Nm³ 3 / h approx. 0.05Nm 3 Pressure drop: Several minutes to several tens of minutes; almost none. Detection methods: Reliable through pressure monitoring; reliant on olfaction and patrols.

[0113] Based on the above, it can be said that hydrogen pipelines are systems that, rather than "continuing to leak" in the event of a leak, lose pressure on their own and quickly resolve dangerous situations.

[0114] 3. Estimation of the reach of the flammable area (4 to 75%) Assumption • No wind • Outdoors • Open to the atmosphere • Supersonic jet → rapid diffusion • Vertical or horizontal ejection

[0115] Guidelines for high concentration ranges by pore size The distance at which the 75% combustible zone is established from a pore size of 4. Approximately a few centimeters around a 0.1 mm hole. 1mm approx. 0.5m 5mm, approximately 2 to 3m

[0116] Thus, hydrogen has an extremely small molecular weight and immediately disperses by buoyancy after being released. For this reason, the flammable concentration range is limited to the vicinity of the discharge point. In other words, a stagnant area like that of city gas is not formed.

[0117] Considering the above, if one of the systems of the first pipeline 11 and the second pipeline 12 is shut off at intervals of one unit of time and the pressure change ΔP / Δt during the shutdown is monitored, a leak can be detected.

[0118] Specifically, the detection capabilities for each pore size are as follows:

[0119] Detection by pressure monitoring of hole diameter 0.1mm, detectable within a few hours. Detected within 1 mm in a few minutes 5mm Instant Detection

[0120] In other words, in hydrogen pipelines, pressure drop behavior corresponding to the diameter of the leak hole is actively detected, ranging from minute leaks to mechanical damage. In particular, this system utilizes the property of hydrogen that the pressure inside the pipe drops autonomously when a leak occurs, achieving highly reliable and low-cost safety management without relying on gas sensors.

[0121] However, if the hole diameter is 1 mm, it is considered better to detect it immediately. For example, on the demand side, 72 Nm 3 Assume that hydrogen is consumed at a rate of / h. This amount of hydrogen is equivalent to that of a 100KW fuel cell. Under these conditions, estimate the time required for a 1mm hole to be detected by a flow meter.

[0122] 1.Prerequisites Supply side: In operation (pressure control and flow rate control enabled) Demand side: In operation (72Nm) 3 / h consumption) Leak hole: 1 mm Automatic shutoff: None Under these conditions, the pressure inside the piping will not drop to atmospheric pressure in a short period of time.

[0123] 2. The correct physical image The pressure inside the piping during operation is determined by the balance between "supply capacity" and "demand + leakage". In other words: Supply flow rate = Demand flow rate + Leakage flow rate As long as the supplier maintains pressure control (e.g., 0.8 to 0.9 MPa), the pressure inside the piping will be largely maintained, even if there is a leak, as long as the supplier can keep up.

[0124] Actual behavior when a 3.1mm hole is drilled Assumed operating conditions Demand: 72Nm 3 / h Effective leakage rate: 2 to 5 Nm 3 / h Supply side: Constant pressure control

[0125] At this time, Pressure: Approximately constant (0.8 to 0.9 MPa) Supply-side flow rate: Increases by the sum of demand and leakage. Energy within the pipe: Maintained (not attenuated)

[0126] Thus, even with a 1mm hole, the pressure inside the piping does not decrease during operation and without automatic shutoff.

[0127] 4. Safety Indicators In this case, "sound" can serve as an indicator.

[0128] Leakage sound from a 5.1mm hole physical background 1mm hole Pipe pressure: 0.8 to 0.9 MPa atmospheric release Flow: Choke flow (sonic jet) Under these conditions, a supersonic jet results in separation and turbulence, and continuous noise containing high-frequency components.

[0129] The general range based on literature and empirical evidence is as follows: Hole diameter Sound pressure level (1m) 0.1mm: Almost silent and difficult to detect. 1mm 60 to 75dB 5mm 80 to 100dB Therefore, a 1mm hole will produce a leakage sound of 60dB or more.

[0130] 6. Worst-case scenario During operation when the automatic shutoff is not activated, the pressure inside the piping is maintained by hydrogen supply from the supply side. In this case, the abnormality manifests not as a pressure drop, but as an increase in supply flow rate, a flow rate difference, and leakage noise.

[0131] Administrative decision regarding 7.1mm holes Role of each detection method Means and roles Flow rate difference detected within a few minutes to 10 minutes. Leaked sound, immediate (person or sensor) Check after pressure drop and shutdown.

[0132] As described above, in this system, if a leak occurs during operation, the pressure inside the piping is maintained by hydrogen supply from the supply side. Therefore, the leak is detected not as a pressure drop, but as an increase in the supply flow rate, a difference in flow rates between the supply and demand sides, and a leak sound. Subsequently, a system shutoff is performed, enabling definitive leak detection using the pressure drop behavior.

[0133] The worst-case scenario (clarification of definition) In this explanation, the "worst-case scenario" refers to a situation where an opening of approximately 5 mm occurs due to mechanical damage or other reasons during operation.

[0134] • Phase 1: A leak has occurred during operation (before shutoff). Leak hole diameter: 5mm (maximum damage expected) Piping: Hydrogen pipeline (20A, approximately 1km) Pipe pressure: 0.8 to 0.9 MPa (supply side pressure under control) Supply side: In operation (no interruption) Demand side: Operating (72Nm) 3 / h consumption) Automatic shutoff: None

[0135] • Phase 2: State shut down after an anomaly detection. Cutting off both the supply and demand sides The leak hole (5mm) remains open. The piping will be in a confined section.

[0136] Phase 1: Operational behavior (before shutdown) Because the supply side controls the pressure, the pressure inside the piping does not drop immediately. The leak manifested itself in the following ways: Surge in supply-side flow Significant difference between supply-side flow rate and demand-side flow rate A very loud jet of sound coming from the leak. Approximate level of sound leakage (5mm hole) Pipe pressure: 0.8 to 0.9 MPa Open to the atmosphere / choke flow (sonic jet) A continuous gas emission sound of approximately 80 to 100 dB is generated. (Depending on the surrounding environment, a person may immediately recognize the abnormality.) * At this stage, a drop in pressure is not the primary detection indicator.

[0137] Phase 2: Behavior after isolation (confinement state) If an abnormality is detected by flow rate difference, leakage sound, etc., and the supply and demand sides are shut off: The inside of the pipe becomes a closed space that holds a finite amount of hydrogen. The pressure drops rapidly due to the release from the 5mm hole.

[0138] Pressure drop indicator (after shutoff, 5mm hole) Elapsed time, pressure inside the pipe Immediately after shutoff: approximately 0.9 MPa Approximately 0.45MPa after approximately 1 minute Approximately 0.25MPa after approximately 2 minutes Approximately 3 minutes later, the chalk technique is finished. Approximately 5 to 6 minutes later, near atmospheric pressure. Therefore, within a few minutes of the shutoff, the hazardous energy inside the pipes is effectively released.

[0139] As described above, in this system, even if the largest damaged hole (approximately 5 mm) occurs during operation, the leak will immediately manifest as a sudden increase in supply flow rate, a flow rate difference, and a loud leaking sound. By shutting off the system after detecting the anomaly, the piping becomes confined, and the pressure drops to near atmospheric pressure within a few minutes due to the release from the leak hole.

[0140] Therefore, even under the worst-case scenario, this system possesses structural safety that prevents it from retaining dangerous energy for extended periods. Its two-stage safety philosophy—detection by flow rate and sound during operation, and termination by pressure drop after shutoff—consistently manages everything from minor leaks to maximum damage.

[0141] Here, we assume that no hole is detected and hydrogen continues to be supplied to the 20A 1km pipeline at 0.9MPa. The hourly hydrogen leakage rates from the 0.1mm, 1mm, and 5mm holes in this case are shown.

[0142] Representative value: Hydrogen: 20°C (293K) Emission coefficient: C d =0.7 atmospheric release Supply pressure: 0.9 MPa (assuming gauge pressure = absolute pressure 1.0 MPa) Let's assume that.

[0143] Pore ​​diameter Leakage amount (Nm 3 / h) 0.1mm approx. 0.14 1mm approx. 13.7 5mm approx. 344 *Since it is proportional to the pore area, the ratio increases 100 times from 0.1mm to 1mm, and 25 times from 1mm to 5mm.

[0144] If the holes are 1 mm or 5 mm in size, a flow meter will detect the leak. A leak is suspected if the flow meter readings on the supply side are lower than the sum of the flow meter readings on the demand side.

[0145] Here, we show the relationship (basic form) that can be seen from the flow rate difference. If there is a leak somewhere in the piping, the conservation of mass is as follows: Supply-side flow rate = (sum of demand-side flow rates) + leakage flow rate

[0146] Therefore, normally, if the sum of the supply-side flow rate and the demand-side flow rate is greater than the sum of the demand-side flow rates, a leak (or blow-off) is suspected. Conversely, if the sum of the supply-side flow rate and the sum of the demand-side flow rates is less likely to be a leak, it is more likely to be due to calibration errors or response delays in the flow meter, or temperature and pressure corrections (Nm). 3 Possible causes include mismatch in conversion standards, gas accumulation along the way (line pack: while internal piping pressure is rising), bypass / backflow, etc.

[0147] Therefore, the judgment logic is basically as follows:

[0148]

number

[0149] 1mm hole: approx. 13.7Nm 3 / h 5mm: approx. 344Nm 3 / h Due to the leak, demand is 72 Nm 3 In the case of / h, 1mm hole: The supply is approximately 86Nm 3 Increases to around / h 5mm: Supply is approximately 410Nm 3 Increases to around / h These values ​​will be clearly detectable with normal instrumentation.

[0150] Here, we will explain the consistency with the phenomenon that "as demand increases, leakage decreases." When the local pressure drops or flow "competition" occurs due to the pull-in on the demand side, the effective leakage from the leak hole will be smaller than the maximum value shown above. Even so, for a 1 mm hole, in most cases it will be several Nm 3 Since values ​​above / h will remain, it is practical to use the following thresholds in relative combination.

[0151]

number

[0152] Now, let's consider the case where the pressure at which hydrogen is supplied drops to 0.6 MPa. Even at 0.6 MPa, as long as it is released into the atmosphere (0.1 MPa), the flow from the hole is still a choked flow (sonic flow). Therefore, it can be assumed that the amount of leakage decreases roughly in proportion to the absolute pressure upstream.

[0153] If hydrogen is continuously supplied at 0.6 MPa, the leakage rate (Nm³) 3 / h) is as follows:

[0154] In the case of a 0.6 MPa gauge pressure (= absolute pressure of 0.7 MPa) (The previous result of 0.9 MPa, G=1.0 MPa abs was multiplied by 0.7) Pore ​​diameter Leakage amount (Nm 3 / h) 0.1mm approx. 0.10 1mm approx. 9.6 5mm approx. 241

[0155] In a 1 mm hole, leakage is 8 to 10 Nm 3 The scale will be / h. Demand is 72Nm 3 For / h, the supply side is 80 to 82 Nm 3 This results in a flow rate difference of / h. Therefore, detection is possible sufficiently by measuring the flow rate difference.

[0156] In a 5mm hole, the leakage is 200 Nm 3 The flow rate exceeds [number] hours. On the supply side, the flow rate jumps sharply. Therefore, it immediately becomes apparent as an anomaly. For this reason, detection is possible simply by measuring the flow rate difference.

[0157] Based on the above considerations, the safety design of the hydrogen pipeline system will be developed.

[0158] Next, the configuration of the data processing unit 4 will be explained using Figure 3. Figure 3 is a block diagram of the data processing unit as a safety control device for a hydrogen pipeline system in Embodiment 1.

[0159] As shown in Figure 3, the data processing unit 4 comprises an acquisition unit 4a, a determination unit 4b, and a control unit 4c.

[0160] The acquisition unit 4a has the function of acquiring the measured values ​​from each pressure gauge and each flow meter. The determination unit 4b has the function of determining whether or not hydrogen is leaking, the location of the hydrogen leak, and the scale of the leak based on the measured values ​​from each pressure gauge and each flow meter. The control unit 4c has the function of controlling each motorized shut-off valve according to the determination result of the determination unit 4b.

[0161] Next, the leak test procedure for the first pipeline 11 will be explained using Figure 4. Figure 4 is a flowchart illustrating the leak test procedure using the safety control device for the hydrogen pipeline system in Embodiment 1.

[0162] First, in step S1, the control unit 4c closes the electric shut-off valves M1, M4, and M5. Then, in step S2, the acquisition unit 4a acquires the measured values ​​of the pressure gauges P1, P6, P3, and P4 over a predetermined period of time. Then, in step S3, the determination unit 4b grasps the relative magnitudes and temporal changes of each pressure measurement acquired over the predetermined period of time. Then, in step S4, the determination unit 4b determines whether the pressures P1, P6, P3, and P4 are substantially the same and whether the change over the predetermined period of time is within a predetermined range.

[0163] In step S4, if the conditions that the pressure is approximately the same and the change is within a predetermined range are met, the determination unit 4b determines that there is no leakage, and the control unit 4c performs the process in step S5. In step S5, the control unit 4c opens the electric shut-off valves M1, M4, and M5.

[0164] In step S4, if the conditions that the pressures are approximately the same and the change is within a predetermined range are not met, the determination unit 4b performs the process in step S6. In step S6, the determination unit 4b determines whether the pressures P6, P3, and P4 have decreased compared to the pressure P1.

[0165] If, in step S6, pressures P6, P3, and P4 have not decreased compared to pressure P1, the acquisition unit 4a performs the process in step S2. If, in step S6, pressures P6, P3, and P4 have decreased compared to pressure P1, the determination unit 4b determines that a leak exists and performs the process in step S7.

[0166] In step S7, the determination unit 4b determines the magnitude of the leak based on the relationship between the measured pressures P6, P3, and P4 and the pressure P1. Specifically, the determination is made based on the following conditions. (1) Small-scale leakage detection If pressures P6, P3, and P4 are less than pressure P1, and pressures P6, P3, and P4 are approximately the same, the determination unit 4b determines that it is a small-scale leak. (2) Determination of medium-scale leakage If pressures P6, P3, and P4 are significantly lower than pressure P1, and pressures P6, P3, and P4 are approximately the same, the determination unit 4b determines that there is a moderate leak. (3) Large-scale leakage determination If pressures P6, P3, and P4 differ from pressure P1, and pressures P6, P3, and P4 are approximately the same and have dropped to near a predetermined low pressure value (for example, 0.1 MPa), the control device determines that there is a large-scale leak. In this case, the determination unit 4b may determine that the amount of hydrogen inside the first pipeline 11 is limited.

[0167] Subsequently, in step S8, the determination unit 4b compares the relative magnitudes of the measured pressures P6, P3, and P4 to estimate the leak location. Specifically, the determination unit 4b makes a determination based on the following conditions.

[0168] When the pressure P6 is less than the pressures P3 and P4 and the pressures P3 and P4 are substantially the same, the determination unit 4b estimates that there is a leak in the vicinity of the pressure gauge P6. When the pressure P3 is less than the pressures P6 and P4 and the pressures P6 and P4 are substantially the same, the determination unit 4b estimates that there is a leak in the vicinity of the pressure gauge P3. When the pressure P4 is less than the pressures P6 and P3 and the pressures P6 and P3 are substantially the same, the determination unit 4b estimates that there is a leak in the vicinity of the pressure gauge P4. When the pressures P3 and P4 are substantially the same and less than the pressure P6, the determination unit 4b estimates that there is a leak in the section between the pressure gauges P3 and P4.

[0169] Even when these conditions are not met, the determination unit 4b may estimate the leak position based on the change relationship of the pressures P6, P3, and P4 with respect to the pressure P1.

[0170] After that, in step S9, the determination unit 4b records the leak detection result and the leak position estimation result, and outputs an alarm signal as necessary. After that, in step S10, the control unit 4c maintains the electric shut-off valves M1, M4, and M5 in the closed state.

[0171] The leak test procedure for the second pipeline 12 is the same. In this case, in FIG. 4, the electric shut-off valves M1, M4, and M5 may be read as the electric shut-off valves M2, M3, and M6, and the pressure gauges P1, P6, P3, and P4 may be read as the pressure gauges P1, P7, P2, and P5.

[0172] Note that the leak tests for the first pipeline 11 and the second pipeline 12 are performed in different time zones. For example, the leak tests for the first pipeline 11 and the second pipeline 12 are performed alternately. Therefore, the hydrogen pipeline system as an infrastructure is operated without stopping the operation.

[0173] According to Embodiment 1 described above, leak checks are performed on the first pipeline 11 and the second pipeline at different time intervals. Specifically, the presence or absence of hydrogen leakage is determined by determining whether the measured values ​​of the supply-side pressure gauge and the demand-side pressure gauge have decreased by a predetermined value or more compared to the measured value of the reference pressure gauge. Therefore, stable and safe operation can be achieved in the hydrogen pipeline system.

[0174] Furthermore, the measured values ​​of supply-side pressure, demand-side pressure, and reference pressure obtained in the shut-off state may not be limited to simple pressure value comparisons, but may also be analyzed using the amount of change over time, the rate of change, or its time derivative. This allows for highly accurate detection of minute leaks and gradual pressure drops.

[0175] Furthermore, the location and scale of the hydrogen leak can also be estimated. Therefore, the leak situation can be understood more accurately.

[0176] Alternatively, when the supply-side shut-off valve and the demand-side shut-off valve are open, the presence or absence of hydrogen leakage may be determined based on the difference between the flow rate readings of the supply-side flow meter and the demand-side flow meter. In this case, if hydrogen leakage is detected, the supply-side shut-off valve and the demand-side shut-off valve should be closed. Even in this case, stable and safe operation of the hydrogen pipeline system can be achieved.

[0177] As described above, this disclosure differs from the safety philosophy of underground gas pipelines and is based on the following characteristics.

[0178] ·Open atmosphere environment (on pillars, overhead, rooftops, etc.) • Small diameter piping (e.g., 20A) • Relatively low pressure (approximately 0.6 to 0.9 MPa) • High hydrogen diffusion

[0179] These conditions necessitate the adoption of an operational safety system that combines monitoring during operation with periodic pressure behavior diagnostics, rather than relying solely on the conventional "abnormality = immediate shutdown" approach.

[0180] In particular, the present disclosure is composed of the following four technical elements. 1. Three-point pressure comparison Using a supply-side pressure gauge, a demand-side pressure gauge, and a reference pressure gauge to remove disturbances (supply pressure fluctuations, temperature changes). 2. Flow rate difference monitoring During operation, detect leakage based on the difference between the supply flow rate and the demand flow rate. 3. Pressure behavior monitoring Determine leakage from pressure changes with the supply-side and demand-side shut-off valves closed. 4. Double pipeline (alternate diagnosis) Adopt a redundant structure that enables leakage diagnosis without stopping the supply.

[0181] Regarding the leakage amount and detection time, it is as follows.

[0182] Assumed conditions · Pipe: 20A · Inner diameter: approximately 19.6 mm · Length: approximately 1 km · Amount of hydrogen in the pipe: approximately 2.7 Nm 3 · Pressure: 0.6 to 0.9 MPa

[0183] Leakage aperture and leakage amount (approximate) 0.1 mm: approximately 0.1 Nm 3 / h 1 mm: approximately 8 to 14 Nm 3 / h 5 mm: approximately 200 to 340 Nm 3 / h

[0184] Detection examples Demand 72 Nm 3 / h (approximate 100 kW fuel cell) during operation 1 mm hole → Supply flow rate is approximately 80 Nm 3 / h, and the flow rate difference can be detected within a few minutes to about 10 minutes. 5 mm hole → Hundreds of Nm 3 / h scale, and it can be detected as an immediate abnormality.

[0185] · Safety of line pack (amount of hydrogen in the pipe) The amount of hydrogen in the piping is approximately 2.7 Nm³. 3 The amount of energy released during a leak is finite. After containment, the energy is released from the leak point, and the hazardous energy is released in a relatively short time. This point is important for explaining safety.

[0186] • Safety considerations unique to pipelines located in open-air spaces This disclosure describes a safety design based on the following conditions, rather than underground gas piping. • Open to the atmosphere • Small diameter piping • Low-voltage operation • High hydrogen diffusivity Therefore, this disclosure adopts a safety management method consisting of operational monitoring (flow rate difference) + periodic diagnosis (pressure behavior).

[0187] • Expected users Hydrogen infrastructure companies Power companies (core infrastructure) Hydrogen equipment manufacturers EPC companies This disclosure is positioned as a safe operation technology for hydrogen overhead pipelines.

[0188] Next, an example of the data processing unit 4 will be explained using Figure 5. Figure 5 is a hardware configuration diagram of the data processing unit 4 as a safety control device for the hydrogen pipeline system in Embodiment 1.

[0189] Each function of the data processing unit can be implemented by a processing circuit. For example, the processing circuit comprises at least one processor 500a and at least one memory 500b. For example, the processing circuit comprises at least one dedicated hardware 600.

[0190] When the processing circuit comprises at least one processor 500a and at least one memory 500b, each function of the data processing unit is realized by software, firmware, or a combination of software and firmware. At least one of the software and firmware is written as a program. At least one of the software and firmware is stored in at least one memory 500b. At least one processor 500a realizes each function of the data processing unit by reading and executing the program stored in at least one memory 500b. At least one processor 500a is also called a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, or DSP. For example, at least one memory 500b is a non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, EEPROM, etc., or a magnetic disk.

[0191] If the processing circuit includes at least one dedicated piece of hardware 600, the processing circuit may be implemented as, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. For example, each function of the management device may be implemented by a processing circuit. For example, each function of the data processing unit may be implemented together by a processing circuit.

[0192] For each function of the data processing unit 4, some may be implemented by dedicated hardware 600, and others by software or firmware. For example, the functions of the control unit 4c may be implemented by a processing circuit as dedicated hardware 600, while functions other than those of the control unit 4c may be implemented by at least one processor 500a reading and executing a program stored in at least one memory 500b.

[0193] In this way, the processing circuit implements each function of the management device using hardware 600, software, firmware, or a combination thereof. [Explanation of Symbols]

[0194] 1 Hydrogen supply source, 2 Supply piping, 3 Supply-side control equipment, 4 Data processing unit, 4a Acquisition unit, 4b Judgment unit, 4c Control unit, 5 First demand equipment, 6 First demand piping, 7 First demand-side control equipment, 8 Second demand equipment, 9 Second demand piping, 10 Second demand-side control equipment, 11 First pipeline, 12 Second pipeline, 500a Processor, 500b Memory, 600 Hardware

Claims

1. The first pipeline is located in an open space, The second pipeline is located in an open space, A first supply-side shutoff valve is provided on the hydrogen supply side in the piping system including the first pipeline, A second supply-side shutoff valve is provided on the hydrogen supply side in the piping system including the second pipeline, A first demand-side shutoff valve is provided on the hydrogen demand side in the piping system including the first pipeline, A second demand-side shutoff valve is provided on the hydrogen demand side in the piping system including the second pipeline, A first supply-side pressure gauge is provided on the hydrogen supply side downstream of the first supply-side shutoff valve in the piping system including the first pipeline, A second supply-side pressure gauge is provided on the hydrogen supply side downstream of the second supply-side shutoff valve in the piping system including the second pipeline, A first demand-side pressure gauge is provided on the hydrogen demand side upstream of the first demand-side shutoff valve in the piping system including the first pipeline, A second demand-side pressure gauge is provided on the hydrogen demand side upstream of the second demand-side shutoff valve in the piping system including the second pipeline, In a piping system including the first pipeline and the second pipeline, a reference pressure gauge is provided on the hydrogen supply side upstream of the first supply-side shutoff valve and the second supply-side shutoff valve, In a safety control device for controlling a hydrogen pipeline system equipped with, The aforementioned safety control device is An acquisition unit that acquires the measured values ​​of the first supply-side pressure gauge, the second supply-side pressure gauge, the first demand-side pressure gauge, the second demand-side pressure gauge, and the reference pressure gauge for a predetermined period of time, With the first supply-side shutoff valve and the first demand-side shutoff valve in a closed state, a first determination is made to determine whether or not there is a hydrogen leak in the first pipeline based on the relative relationship or temporal change of the measured values ​​of the first supply-side pressure gauge, the first demand-side pressure gauge, and the reference pressure gauge. With the second supply-side shutoff valve and the second demand-side shutoff valve in a closed state, a second determination is made to determine whether or not there is a hydrogen leak in the second pipeline based on the relative relationship or temporal change of the measured values ​​of the second supply-side pressure gauge, the second demand-side pressure gauge, and the reference pressure gauge. A determination unit that performs the following at different time intervals, A control unit controls the first supply-side shut-off valve according to the first determination result by the determination unit, and controls the second supply-side shut-off valve according to the second determination result by the determination unit, A safety control device for a hydrogen pipeline system equipped with the following features.

2. The determination unit, With the second supply-side shutoff valve and the second demand-side shutoff valve maintained in the open state, the first determination is made for the first pipeline. The safety control device for a hydrogen pipeline system according to claim 1, wherein the second determination for the second pipeline is performed while the first supply-side shutoff valve and the first demand-side shutoff valve are maintained in an open state.

3. The control unit, If the first determination result is determined to be that there is a hydrogen leak in the first pipeline, By keeping the first supply-side shutoff valve and the first demand-side shutoff valve in a closed state, while keeping the second supply-side shutoff valve and the second demand-side shutoff valve in an open state, Continue supplying hydrogen through the second pipeline. If the second determination result indicates that there is a hydrogen leak in the second pipeline, By keeping the second supply-side shutoff valve and the second demand-side shutoff valve in a closed state, while keeping the first supply-side shutoff valve and the first demand-side shutoff valve in an open state, A safety control device for a hydrogen pipeline system according to claim 1 or 2, which continues the supply of hydrogen through the first pipeline.

4. The safety control device according to claim 1 or 2, wherein the determination unit determines, in the first determination or the second determination, whether or not hydrogen leakage is present based on the amount of change in time, the rate of change, or the time derivative of the measured value.

5. The first pipeline is located in an open space, The second pipeline is located in an open space, A first supply-side shutoff valve is provided on the hydrogen supply side in the piping system including the first pipeline, A second supply-side shutoff valve is provided on the hydrogen supply side in the piping system including the second pipeline, A first demand-side shutoff valve is provided on the hydrogen demand side in the piping system including the first pipeline, A second demand-side shutoff valve is provided on the hydrogen demand side in the piping system including the second pipeline, A first supply-side pressure gauge is provided on the hydrogen supply side downstream of the first supply-side shutoff valve in the piping system including the first pipeline, A second supply-side pressure gauge is provided on the hydrogen supply side downstream of the second supply-side shutoff valve in the piping system including the second pipeline, A first demand-side pressure gauge is provided on the hydrogen demand side upstream of the first demand-side shutoff valve in the piping system including the first pipeline, A second demand-side pressure gauge is provided on the hydrogen demand side upstream of the second demand-side shutoff valve in the piping system including the second pipeline, In a piping system including the first pipeline and the second pipeline, a reference pressure gauge is provided on the hydrogen supply side upstream of the first supply-side shutoff valve and the second supply-side shutoff valve, In a safety control method for controlling a hydrogen pipeline system equipped with, With the second supply-side shutoff valve and the second demand-side shutoff valve in the open position, the first supply-side shutoff valve and the first demand-side shutoff valve are closed. The measured values ​​of the first supply-side pressure gauge, the first demand-side pressure gauge, and the reference pressure gauge are acquired for a predetermined period of time. A first determination is made to determine whether or not there is a hydrogen leak in the first pipeline based on the relative relationship or temporal change of the measured values. With the first supply-side shutoff valve and the first demand-side shutoff valve kept in the open position, the second supply-side shutoff valve and the second demand-side shutoff valve are closed. The measured values ​​of the second supply-side pressure gauge, the second demand-side pressure gauge, and the reference pressure gauge are acquired for a predetermined period of time. A step of performing a second determination to determine whether or not there is a hydrogen leak in the second pipeline based on the relative relationship or temporal change of the measured values ​​at a time period different from the first determination, A safety control method for a hydrogen pipeline system, including the system itself.

6. If the result of the first determination is that there is a hydrogen leak in the first pipeline, By keeping the first supply-side shutoff valve and the first demand-side shutoff valve in a closed state, while keeping the second supply-side shutoff valve and the second demand-side shutoff valve in an open state, The process of continuing the supply of hydrogen through the second pipeline, If the result of the second determination is that there is a hydrogen leak in the second pipeline, By keeping the second supply-side shutoff valve and the second demand-side shutoff valve in a closed state, while keeping the first supply-side shutoff valve and the first demand-side shutoff valve in an open state, The process of continuing the supply of hydrogen through the first pipeline, A safety control method for a hydrogen pipeline system according to claim 5, including the following:

7. The safety control method according to claim 5 or 6, wherein in the step of performing the first determination or the second determination, the presence or absence of hydrogen leakage is determined based on the amount of change in time, the rate of change, or the time derivative of the measured value.

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