METHOD OF OPERATING HYDROGEN GAS SUPPLY SYSTEM

Abstract

A method of operating a hydrogen gas supply system according to one aspect of the present disclosure includes purging a sealed purge target area by repeating a step plural times in a row, the step including: supplying an inert gas to the purge target area to increase internal pressure of the purge target area; and then, opening the purge target area to vent the inert gas from the purge target area together with a hydrogen gas.

Claims

1. A method of operating a hydrogen gas supply system, the method comprising purging a sealed purge target area by repeating a step plural times in a row, the step including: supplying an inert gas to the purge target area to increase internal pressure of the purge target area; and then, opening the purge target area to vent the inert gas from the purge target area together with a hydrogen gas.

2. The method according to claim 1, further comprising preventing the hydrogen gas from flowing through a shutoff section by: forming the shutoff section in the hydrogen gas supply system; supplying the inert gas to the shutoff section to increase internal pressure of the shutoff section to predetermined shutoff pressure or more; and maintaining the internal pressure of the shutoff section at the shutoff pressure or more.

3. The method according to claim 2, wherein: a flow control valve that adjusts a supply flow rate of the hydrogen gas is located at the hydrogen gas supply system; and the shutoff section is formed upstream of the flow control valve.

4. The method according to claim 2, wherein: the hydrogen gas supply system includes branch pipes through which the hydrogen gas is supplied to corresponding burners; and the shutoff section is formed at each of the branch pipes.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a schematic diagram of a hydrogen gas supply system.

[0009] FIG. 2 is a diagram showing a supply flow of a hydrogen gas.

[0010] FIG. 3 is a diagram showing a first stand-by state of the hydrogen gas supply system.

[0011] FIG. 4 is a diagram corresponding to Step S1 of the supply flow of the hydrogen gas.

[0012] FIG. 5 is a diagram corresponding to Step S2 of the supply flow of the hydrogen gas.

[0013] FIG. 6 is a diagram corresponding to Step S3 of the supply flow of the hydrogen gas.

[0014] FIG. 7 is a diagram corresponding to Step S4 of the supply flow of the hydrogen gas.

[0015] FIG. 8 is a diagram corresponding to Step S5 of the supply flow of the hydrogen gas.

[0016] FIG. 9 is a diagram showing a supply stop flow of the hydrogen gas.

[0017] FIG. 10 is a diagram corresponding to Step S11 of the supply stop flow of the hydrogen gas.

[0018] FIG. 11 is a diagram corresponding to Step S12 of the supply stop flow of the hydrogen gas.

[0019] FIG. 12 is a diagram corresponding to Step S13 of the supply stop flow of the hydrogen gas.

[0020] FIG. 13 is a diagram corresponding to Step S13 of the supply stop flow of the hydrogen gas.

[0021] FIG. 14 is a diagram corresponding to Step S14 of the supply stop flow of the hydrogen gas.

[0022] FIG. 15 is a diagram corresponding to Step S15 of the supply stop flow of the hydrogen gas.

[0023] FIG. 16 is a diagram corresponding to Step S16 of the supply stop flow of the hydrogen gas.

[0024] FIG. 17 is a diagram corresponding to Step S17 of the supply stop flow of the hydrogen gas.

[0025] FIG. 18 is a diagram corresponding to Step S18 of the supply stop flow of the hydrogen gas.

DESCRIPTION OF EMBODIMENTS

Entire Configuration of Hydrogen Gas Supply System

[0026] Hereinafter, a method of operating a hydrogen gas supply system 100 will be described. First, an entire configuration of the hydrogen gas supply system 100 will be described. FIG. 1 is a schematic diagram of the hydrogen gas supply system 100. The hydrogen gas supply system 100 of the present embodiment is a system that supplies a hydrogen gas to burners (first to third burners).

[0027] As shown in FIG. 1, the hydrogen gas supply system 100 includes a main pipe 10, a hydrogen gas header 20, and branch pipes 30. The following will describe these components in order.

<Main Pipe>

[0028] The main pipe 10 is a pipe through which the hydrogen gas supplied to the hydrogen gas supply system 100 is guided to the hydrogen gas header 20. A fuel shutoff valve 11, a main shutoff section upstream valve 12, a main shutoff section downstream valve 13, and a flow control valve 14 are located at the main pipe 10.

[0029] The fuel shutoff valve 11 is located at a most upstream position in the hydrogen gas supply system 100. By opening the fuel shutoff valve 11, the hydrogen gas is supplied to the hydrogen gas supply system 100. In contrast, by closing the fuel shutoff valve 11, the supply of the hydrogen gas to the hydrogen gas supply system 100 stops.

[0030] The main shutoff section upstream valve 12 is located downstream of the fuel shutoff valve 11. In the present embodiment, an area between the fuel shutoff valve 11 and the main shutoff section upstream valve 12 in the hydrogen gas supply system 100 is referred to as an upstream area 91. A first vent pipe 41 is located at a portion of the main pipe 10 which corresponds to the upstream area 91.

[0031] The first vent pipe 41 is a pipe through which the gas in the upstream area 91 is vented to an outside of the hydrogen gas supply system 100. A first vent valve 42 is located at the first vent pipe 41. By opening the first vent valve 42, the gas in the upstream area 91 is vented to the outside of the hydrogen gas supply system 100 through the first vent pipe 41.

[0032] The main shutoff section downstream valve 13 is located downstream of the main shutoff section upstream valve 12. In the present embodiment, a section of the main pipe 10 which is located between the main shutoff section upstream valve 12 and the main shutoff section downstream valve 13 is referred to as a main shutoff section 15. A main pressure gauge 16, a first inert gas supply pipe 51, and a second vent pipe 43 are located at a portion of the main pipe 10 which corresponds to the main shutoff section 15.

[0033] The main pressure gauge 16 is measuring equipment that measures the internal pressure of the main shutoff section 15.

[0034] The first inert gas supply pipe 51 is a pipe through which the inert gas is supplied to the main shutoff section 15. The first inert gas supply pipe 51 connects the main shutoff section 15 and an inert gas header 50, and a first inert gas supply valve 52 is located at the first inert gas supply pipe 51. By opening the first inert gas supply valve 52, the inert gas is supplied from the inert gas header 50 through the first inert gas supply pipe 51 to the main shutoff section 15. One example of the inert gas is a nitrogen gas.

[0035] The second vent pipe 43 is a pipe through which the gas in the main shutoff section 15 is vented to the outside of the hydrogen gas supply system 100. A second vent valve 44 is located at the second vent pipe 43. By opening the second vent valve 44, the gas in the main shutoff section 15 is vented to the outside of the hydrogen gas supply system 100 through the second vent pipe 43.

[0036] The flow control valve 14 is located downstream of the main shutoff section downstream valve 13. To be specific, the main shutoff section 15 is located upstream of the flow control valve 14. The flow control valve 14 is a valve that adjusts a supply flow rate of the hydrogen gas (in the present embodiment, the supply flow rate of the hydrogen gas to be supplied to the burners). A third vent pipe 45 is located at a portion of the main pipe 10 which is located downstream of the flow control valve 14 (i.e., a portion of the main pipe 10 which is located between the flow control valve 14 and the hydrogen gas header 20).

[0037] The third vent pipe 45 is a pipe through which the gas in a portion of the main pipe 10 which is located downstream of the main shutoff section downstream valve 13 is vented to the outside of the hydrogen gas supply system 100. A third vent valve 46 is located at the third vent pipe. By opening the third vent valve 46, the gas in the portion of the main pipe 10 which is located downstream of the main shutoff section downstream valve 13 is vented to the outside of the hydrogen gas supply system 100 through the third vent pipe 45.

<Hydrogen Gas Header>

[0038] The hydrogen gas header 20 is located downstream of the main pipe 10 and is supplied with the hydrogen gas from the main pipe 10. The hydrogen gas header 20 has a function of temporarily storing the hydrogen gas supplied from the main pipe 10 and distributes the stored hydrogen gas to the branch pipes 30. Moreover, a hydrogen gas header pressure gauge 21 and a second inert gas supply pipe 53 are located at the hydrogen gas header 20.

[0039] The hydrogen gas header pressure gauge 21 is measuring equipment that measures the internal pressure of the hydrogen gas header 20.

[0040] The second inert gas supply pipe 53 is a pipe through which the inert gas is supplied to the hydrogen gas header 20. The second inert gas supply pipe 53 connects the hydrogen gas header 20 and the inert gas header 50, and a second inert gas supply valve 54 is located at the second inert gas supply pipe 53. By opening the second inert gas supply valve 54, the inert gas is supplied from the inert gas header 50 through the second inert gas supply pipe 53 to the hydrogen gas header 20.

<Branch Pipes>

[0041] The branch pipes 30 are pipes through which the hydrogen gas is guided from the hydrogen gas header 20 to the burners. The hydrogen gas supply system 100 of the present embodiment includes the branch pipes 30 (in FIG. 1, three branch pipes 30). Each branch pipe 30 supplies the hydrogen gas to the corresponding burner. In accordance with an operating state of a combustion facility including the burners, all of the branch pipes 30 may supply the hydrogen gas to the burners, or only some of the branch pipes 30 may supply the hydrogen gas to the burners.

[0042] The branch pipes 30 are the same in configuration as each other. A branch shutoff section upstream valve 31, a branch shutoff section downstream valve 32, a check valve 33, and a frame arrester 34 are located at each branch pipe 30.

[0043] The branch shutoff section upstream valve 31 is located at an upstream position in the branch pipe 30. In the present embodiment, an area between the main shutoff section upstream valve 12 and the branch shutoff section upstream valve 31 in the hydrogen gas supply system 100 is referred to as an intermediate area 92. Moreover, an area located downstream of the branch shutoff section upstream valve 31 in the hydrogen gas supply system 100 is referred to as a downstream area 93.

[0044] The branch shutoff section downstream valve 32 is located downstream of the branch shutoff section upstream valve 31. In the present embodiment, a section of the branch pipe 30 which is located between the branch shutoff section upstream valve 31 and the branch shutoff section downstream valve 32 is referred to as a branch shutoff section 35. A third inert gas supply pipe 55 is located at a portion of the branch pipe 30 which corresponds to the branch shutoff section 35.

[0045] The third inert gas supply pipe 55 is a pipe through which the inert gas is supplied to the branch shutoff section 35. The third inert gas supply pipe 55 connects the branch shutoff section 35 and the inert gas header 50, and a third inert gas supply valve 56 is located at the third inert gas supply pipe 55. By opening the third inert gas supply valve 56, the inert gas is supplied from the inert gas header 50 to the branch shutoff section 35. The third inert gas supply pipes 55 of the present embodiment are partially coupled to each other, but each of the third inert gas supply pipes 55 may independently connect the branch shutoff section 35 and the inert gas header 50.

[0046] Moreover, a branch pressure gauge 36 is located at a portion of the third inert gas supply pipe 55 which is located between the branch shutoff section 35 and the third inert gas supply valve 56. The branch pressure gauge 36 is measuring equipment that measures the internal pressure of the branch shutoff section 35.

[0047] The check valve 33 is located downstream of the branch shutoff section downstream valve 32. The check valve 33 is a valve that allows the flow of the hydrogen gas toward the downstream side (toward the burner) but prohibits the flow of the hydrogen gas toward the upstream side.

[0048] The frame arrester 34 is equipment that prevents flame from entering the branch pipe 30 from the burner, and is installed according to need.

[0049] The foregoing has described the entire configuration of the hydrogen gas supply system 100. In the foregoing, one inert gas supply valve 52, 54, or 56 is located at the inert gas supply pipe 51, 53, or 55 that is the pipe through which the inert gas is supplied to the hydrogen gas supply system 100. However, the inert gas supply valves 52, 54, or 56 may be located in series at the inert gas supply pipe 51, 53, or 55.

(Supply Flow of Hydrogen Gas)

[0050] Next, the supply flow of the hydrogen gas in the hydrogen gas supply system 100 will be described. FIG. 2 is a diagram showing the supply flow of the hydrogen gas. As the supply flow of the hydrogen gas in the hydrogen gas supply system 100, the following will describe the flow from when the hydrogen gas supply system 100 is in a first stand-by state until the hydrogen gas is supplied to the burner.

[0051] First, the first stand-by state will be described. FIG. 3 is a diagram showing the first stand-by state of the hydrogen gas supply system 100. In FIG. 3, thick lines indicate portions filled with the hydrogen gas, and broken lines indicate portions filled with the inert gas. Moreover, symbols of white valves indicate that the valves are open, and symbols of black valves indicate that the valves are closed. The same is true in FIGS. 4 to 8 and 10 to 18 described below.

[0052] As shown in FIG. 3, when the hydrogen gas supply system 100 is in the first stand-by state, the fuel shutoff valve 11, the main shutoff section upstream valve 12, the main shutoff section downstream valve 13, the branch shutoff section upstream valve 31, the branch shutoff section downstream valve 32, and the inert gas supply valves 52, 54, and 56 are closed, and the other valves are open. When the hydrogen gas supply system 100 is in first stand-by state, the hydrogen gas (to be precise, a combustible amount of hydrogen gas) does not exist at the downstream side of the fuel shutoff valve 11 (inside the hydrogen gas supply system 100). Since the branch shutoff section upstream valve 31 and the branch shutoff section downstream valve 32 are closed, the branch shutoff section 35 is shut off.

[0053] When the supply flow of the hydrogen gas starts from the first stand-by state of the hydrogen gas supply system 100, as shown in FIG. 2, first, the inert gas is supplied to the main shutoff section 15 (Step S1). Specifically, as shown in FIG. 4, after the second vent valve 44 is closed, the first inert gas supply valve 52 opens. Thus, the inert gas is supplied to the main shutoff section 15. After that, the internal pressure of the main shutoff section 15 is increased to predetermined main shutoff pressure or more, and then, the first inert gas supply valve 52 is closed, and this state is maintained. In this state, the internal pressure of the main shutoff section 15 is measured by using the main pressure gauge 16 to confirm that there is no leakage. The above-described main shutoff pressure is higher than the pressure of the hydrogen gas supplied to the main shutoff section 15.

[0054] After Step S1 is executed, the hydrogen gas is supplied to the upstream arca 91 (Step S2). Specifically, as shown in FIG. 5, after the first vent valve 42 is closed, the fuel shutoff valve 11 opens. Thus, the hydrogen gas is supplied to the upstream area 91. This state shown in FIG. 5 is referred to as a second stand-by state in the present embodiment.

[0055] After Step S2 is executed, the inert gas is supplied to the branch shutoff section 35 (Step S3). Specifically, as shown in FIG. 6, the third inert gas supply valve 56 opens. Thus, the inert gas is supplied to the branch shutoff section 35. After that, the internal pressure of the branch shutoff section 35 is increased to predetermined branch shutoff pressure or more, and then, the third inert gas supply valve 56 is closed, and this state is maintained. In this state, the internal pressure of the branch shutoff section 35 is measured by using the branch pressure gauge 36 to confirm that there is no leakage. The above-described branch shutoff pressure is higher than the pressure of the hydrogen gas supplied to the branch shutoff section 35.

[0056] After Step S3 is executed, the hydrogen gas is supplied to the intermediate arca 92 (Step S4). Specifically, as shown in FIG. 7, after the third vent valve 46 is closed, the main shutoff section upstream valve 12 and the main shutoff section downstream valve 13 open. Thus, the hydrogen gas is supplied to the intermediate area 92. In this state, the internal pressure of the intermediate area 92 is measured by using the hydrogen gas header pressure gauge 21 to confirm that there is no leakage.

[0057] After Step S4 is executed, the hydrogen gas is supplied to the downstream arca 93 (Step S5). Herein, the hydrogen gas is not supplied to all of the downstream areas 93 but is supplied only to the downstream area(s) 93 corresponding to the burner(s) that requires the supply of the hydrogen gas. For example, when only a first burner requires the supply of the hydrogen gas, as shown in FIG. 8, the branch shutoff section upstream valve 31 and the branch shutoff section downstream valve 32 in the downstream area 93 corresponding to the first burner open. Thus, the hydrogen gas is supplied only to the first burner.

[0058] On the other hand, in each of the downstream areas 93 corresponding to a second burner and a third burner, the branch shutoff section upstream valve 31 and the branch shutoff section downstream valve 32 remain closed, and the branch shutoff section 35 is filled with the inert gas. In addition, the pressure (branch shutoff pressure or more) of the inert gas in the branch shutoff section 35 is higher than the pressure of the hydrogen gas supplied to the branch shutoff section 35. Therefore, in each of the downstream areas 93 corresponding to the second burner and the third burner, even if the branch shutoff section upstream valve 31 includes a gap through which the hydrogen gas that is high in permeability can flow, the hydrogen gas cannot flow through the branch shutoff section 35. To be specific, the hydrogen gas does not leak to the second burner and the third burner. The foregoing has described the supply flow of the hydrogen gas in the hydrogen gas supply system 100.

(Supply Stop Flow of Hydrogen Gas)

[0059] Next, the supply stop flow in the hydrogen gas supply system 100 will be described. The following will describe the flow from when the hydrogen gas supply system 100 is in the state shown in FIG. 8 until the supply of the hydrogen gas to the burner stops, and the hydrogen gas supply system 100 becomes the first stand-by state or the second stand-by state.

[0060] FIG. 9 is a diagram showing the supply stop flow of the hydrogen gas. As shown in FIG. 9, when the supply stop flow of the hydrogen gas starts, first, the intermediate arca 92 and the downstream area 93 are depressurized (Step S11). Specifically, as shown in FIG. 10, after the main shutoff section upstream valve 12, the main shutoff section downstream valve 13, the branch shutoff section upstream valve 31, and the branch shutoff section downstream valve 32 are closed, the second vent valve 44 and the third vent valve 46 open. Thus, the internal pressure of the intermediate area 92 and the internal pressure of the downstream area 93 (the downstream area 93 corresponding to the first burner) decrease, and the intermediate arca 92 and the downstream area 93 are depressurized.

[0061] After Step S11 is executed, the downstream areas 93 are purged (Step S12). Specifically, as shown in FIG. 11, after the branch shutoff section downstream valves 32 open, the third inert gas supply valves 56 for the downstream areas 93 open. Thus, the hydrogen gas existing inside the downstream areas 93 is vented to the outside of the hydrogen gas supply system 100 through the burners. To be specific, the downstream areas 93 are purged.

[0062] After Step S12 is executed, the intermediate area 92 is purged (Step S13). Specifically, as shown in FIG. 12, after the branch shutoff section downstream valves 32, the third inert gas supply valves 56, the second vent valve 44, and the third vent valve 46 are closed, the first inert gas supply valve 52 and the second inert gas supply valve 54 open. Thus, the inert gas is supplied to the intermediate area 92, and this increases (accumulates) the internal pressure of the intermediate area 92. After that, as shown in FIG. 13, the first inert gas supply valve 52 and the second inert gas supply valve 54 are closed, and the second vent valve 44 and the third vent valve 46 open. Thus, the intermediate area 92 is open, and the hydrogen gas is vented from the intermediate area 92 through the second vent pipe 43 and the third vent pipe 45 together with the inert gas. Then, the steps shown in FIGS. 12 and 13 are repeated plural times in a row. Thus, although the intermediate area 92 that is a purge target area has a complex shape, the hydrogen gas can be surely vented from the intermediate area 92. To be specific, highly accurate purge can be executed.

[0063] After Step S13 is executed, the main shutoff section 15 is shut off (Step S14). Specifically, as shown in FIG. 14, the second vent valve 44 is closed. Thus, the main shutoff section 15 is shut off.

[0064] After Step S14 is executed, the inert gas is supplied to the main shutoff section 15 (Step S15). Specifically, as shown in FIG. 15, the first inert gas supply valve 52 opens. Thus, the inert gas is supplied to the main shutoff section 15. Then, after the internal pressure of the main shutoff section 15 is increased the above-described main shutoff pressure or more, the first inert gas supply valve 52 is closed, and this state is maintained. Thus, the hydrogen gas supply system 100 becomes the second stand-by state. To be specific, the hydrogen gas supply system 100 becomes the above-described state shown in FIG. 5. In this case, even if the main shutoff section upstream valve 12 includes a gap through which the hydrogen gas that is high in permeability can flow, the hydrogen gas cannot flow through the main shutoff section 15.

[0065] When the hydrogen gas supply system 100 is made to stand by in the second stand-by state until the supply of the hydrogen gas restarts, the supply stop flow of the hydrogen gas terminates here. In this case, when the supply of the hydrogen gas restarts, the flow starts from Step S3 in FIG. 2. For example, when a period of time until the supply of the hydrogen gas restarts is relatively short, the hydrogen gas supply system 100 may be made to stand by in the second stand-by state.

[0066] On the other hand, when the hydrogen gas supply system 100 is made to stand by in the first stand-by state until the supply of the hydrogen gas restarts, the flow proceeds to Step S16 after Step S15. For example, when the period of time until the supply of the hydrogen gas restarts is relatively long, the hydrogen gas supply system 100 may be made to stand by in the first stand-by state.

[0067] In Step S16, the upstream area 91 is depressurized. Specifically, as shown in FIG. 16, the fuel shutoff valve 11 is closed, and then, the first vent valve 42 opens. Thus, the internal pressure of the upstream area 91 decreases, and the upstream area 91 is depressurized.

[0068] After Step S16 is executed, the upstream arca 91 is purged (Step S17). Specifically, as shown in FIG. 17, the first inert gas supply valve 52 and the main shutoff section upstream valve 12 open. Thus, the inert gas flows into the upstream area 91, and the hydrogen gas is vented through the first vent pipe 41 to the outside of the hydrogen gas supply system 100 together with the inert gas.

[0069] After Step S17 is executed, the hydrogen gas supply system 100 is set to the first stand-by state (Step S18). Specifically, as shown in FIG. 18, after the main shutoff section upstream valve 12 is closed, and the first inert gas supply valve 52 is closed, the second vent valve 44 opens. To be specific, the hydrogen gas supply system 100 is set to the state shown in FIG. 3. In this case, when the supply of the hydrogen gas restarts, the flow starts from Step S1 in FIG. 2. The foregoing has described the supply stop flow of the hydrogen gas in the hydrogen gas supply system 100.

CONCLUSION

[0070] A first aspect disclosed in the present description is a method of operating a hydrogen gas supply system, the method including purging a sealed purge target arca by repeating a step plural times in a row, the step including: supplying an inert gas to the purge target arca to increase internal pressure of the purge target area; and then, opening the purge target area to vent the inert gas from the purge target area together with a hydrogen gas.

[0071] According to this method, the hydrogen gas can be surely vented from the purge target area. To be specific, highly accurate purge can be executed.

[0072] A second aspect disclosed in the present description is the method according to the first aspect, further including preventing the hydrogen gas from flowing through a shutoff section by: forming the shutoff section in the hydrogen gas supply system; supplying the inert gas to the shutoff section to increase internal pressure of the shutoff section to predetermined shutoff pressure or more; and maintaining the internal pressure of the shutoff section at the shutoff pressure or more.

[0073] According to this method, since the hydrogen gas cannot flow through the shutoff section, the flow of the hydrogen gas can be stopped by the shutoff section.

[0074] A third aspect disclosed in the present description is the method according to the second aspect, wherein: a flow control valve that adjusts a supply flow rate of the hydrogen gas is located at the hydrogen gas supply system; and the shutoff section is formed upstream of the flow control valve.

[0075] According to this method, the flow of the hydrogen gas can be stopped at the upstream side of the flow control valve.

[0076] A fourth aspect disclosed in the present description is the method according to the second or third aspect, wherein: the hydrogen gas supply system includes branch pipes through which the hydrogen gas is supplied to corresponding burners; and the shutoff section is formed at each of the branch pipes.

[0077] According to this configuration, the flow of the hydrogen gas can be stopped at each branch pipe.

REFERENCE SIGNS LIST

[0078] 14 flow control valve [0079] 15 main shutoff section (shutoff section) [0080] 30 branch pipe [0081] 35 branch shutoff section (shutoff section) [0082] 92 intermediate area (purge target area) [0083] 100 hydrogen gas supply system