Hydrogen circulation device and hydrogen circulation method

Abstract

This hydrogen circulation device recovers hydrogen from a generator via a hydrogen recovery line and stores the hydrogen in the first tank. The hydrogen stored in the first tank is compressed by a compressor and stored in a second tank. The hydrogen stored in the second tank is supplied to the generator via a hydrogen supply line.

Description

Hydrogen circulation device and hydrogen circulation method

[0001] This application claims priority to Japanese Patent Application No. 2023-208187, filed with the Japan Patent Office on December 11, 2023, the contents of which are incorporated herein by reference.

[0002] Some generators driven by power in power plants have a cooling structure that can cool them by heat exchange with hydrogen supplied as a cooling medium to suppress heat generation during operation. Hydrogen can be supplied from an external cylinder, but when the remaining amount in the cylinder becomes low, it is necessary to replace the cylinder as needed to maintain cooling performance.

[0003] Patent Document 1 discloses an example of a rotary machine that can be cooled using this type of hydrogen as a cooling medium. This document states that hydrogen released into the atmosphere can be reduced by recovering excess hydrogen generated depending on the load on the rotary machine using a pump and storing it in a tank, and then supplying it from the tank to the rotary equipment as needed.

[0004] Japanese Unexamined Patent Publication No. 60-74944

[0005] In general, as the amount of electricity generated by a generator increases, the amount of heat generated also increases. Therefore, the pressure of the hydrogen supplied to the generator for cooling purposes is adjusted so that sufficient cooling can be achieved during rated operation, when the amount of heat generated is at its maximum. However, when the generator is operated at partial load, the amount of heat generated is relatively low, so the hydrogen pressure in the generator becomes higher than necessary. Such excessive hydrogen pressure can lead to increased hydrogen consumption due to increased hydrogen leakage from the generator to the outside, and can also lead to reduced performance due to increased windage loss in the generator.

[0006] One possible solution to this problem is to recover excess hydrogen for the generator in a tank and then supply it back to the generator as needed, as described in Patent Document 1. However, in Patent Document 1, a pump is used to recover hydrogen from the generator, and the recovery speed depends on the performance of the pump. Therefore, in order to recover excess hydrogen responsively in accordance with the operating state of the generator, it is necessary to improve the pump performance, which could increase equipment costs.

[0007] At least one embodiment of the present invention has been made in consideration of the above circumstances, and aims to provide a hydrogen circulation device and a hydrogen circulation method that can recover and supply hydrogen with good responsiveness according to the operating state of the generator.

[0008] In order to solve the above-mentioned problems, at least one embodiment of the hydrogen circulation device of the present disclosure is a hydrogen circulation device for circulating hydrogen for cooling a generator, and includes: a hydrogen recovery line for recovering the hydrogen from the generator; a first tank for storing the hydrogen recovered from the hydrogen recovery line; a compressor for compressing the hydrogen stored in the first tank; a second tank for storing the hydrogen compressed by the compressor; and a hydrogen supply line for supplying the hydrogen stored in the second tank to the generator.

[0009] In order to solve the above-mentioned problems, at least one embodiment of the hydrogen circulation method of the present disclosure is a hydrogen circulation method for circulating hydrogen for cooling a generator, comprising the steps of: storing the hydrogen recovered from the generator in a first tank; compressing the hydrogen stored in the first tank and storing it in a second tank; and supplying the hydrogen stored in the second tank to the generator.

[0010] According to at least one embodiment of the present disclosure, it is possible to provide a hydrogen circulation device and a hydrogen circulation method that can recover and supply hydrogen with good responsiveness in accordance with the operating state of a power generator.

[0011] FIG. 1 is a configuration diagram schematically showing a power plant 1 according to one embodiment. FIG. 2 is a flowchart showing a method of operating the hydrogen circulation device during normal operation of the power plant 1 of FIG. 1. FIG. 3 is a configuration diagram showing an operating state corresponding to step S3 of FIG. 2. FIG. 4 is a configuration diagram showing an operating state corresponding to step S4 of FIG. 2. FIG. 5 is a configuration diagram showing an operating state corresponding to step S8 of FIG. 2. FIG. 6 is a configuration diagram showing an operating state corresponding to step S11 of FIG. 2. FIG. 7 is a configuration diagram showing an operating state in another operating method of the hydrogen circulation device of FIG. 1.

[0012] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the configurations described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0013] First, a power plant 1 including a hydrogen circulation system according to at least one embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a schematic diagram illustrating the configuration of the power plant 1 according to one embodiment.

[0014] The power plant 1 includes a gas turbine 2 and a generator 4 that is connected to the gas turbine 2 and is capable of generating electricity using the power output from the gas turbine 2 .

[0015] The gas turbine 2 includes a compressor 6, a combustor 8, and a turbine 10. The compressor 6 generates compressed air by compressing combustion air A (e.g., outside air). The combustor 8 receives hydrogen H as fuel F from a fuel supply system 12. ２ The fuel supply system 12 supplies fuel F (hydrogen H ２ The hydrogen supply equipment 14 can supply hydrogen H ２ The facility is for supplying hydrogen, for example, a hydrogen park facility including hydrogen tanks and hydrogen production equipment.

[0016] The combustor 8 generates combustion gas by mixing and burning fuel F supplied from a fuel supply system 12 with compressed air from the compressor 6. The combustion gas drives the turbine 10, and after completing its work, the combustion gas is discharged to the outside as exhaust gas Gex through an exhaust duct (not shown).

[0017] The generator 4 has a generator rotor 20 that is formed integrally with the gas turbine rotor 18 of the gas turbine 2. The generator rotor 20 is rotatably supported on both sides by a pair of bearings 24 relative to a generator casing 22. Furthermore, seal members 26 are provided inside the pair of bearings 24 to prevent leakage of oil sealed inside the generator casing 22.

[0018] The generator 4 uses hydrogen H as a cooling medium. ２ The cooling structure uses a hydrogen H ２ 1 shows the operating state of the power plant 1 during normal operation, in which hydrogen H 2 is supplied as fuel to the gas turbine 2 from the hydrogen supply facility 14. ２ A portion of the hydrogen is sealed in advance in the generator 4 through a fuel branch line 33 branching from the fuel supply line 16 (in FIG. 1, the hydrogen is supplied to the generator 4 through the fuel branch line 33). ２ Since the fuel is already sealed in the fuel branch line 33, the fuel branch line 33 is shown in a state in which it is blocked by closing the valve V5. In this way, hydrogen H ２ is supplied to the cooling structure as a cooling medium, the hydrogen supply equipment 14 can be supplied as a cooling medium separately from the hydrogen supply equipment 14. ２ This eliminates the need to provide an additional supply source for supplying the gas, thereby effectively reducing equipment costs.

[0019] The hydrogen H ２ The pressure P of the hydrogen H ２The recovery or supply of hydrogen H in the generator 4 is controlled within an allowable range for maintaining an appropriate operating state. This allowable range is defined by a first reference value Pref1 as an upper limit value and a second reference value Pref2 as a lower limit value. ２ The pressure P can be detected by a pressure sensor 29 provided in the generator casing 22 .

[0020] The hydrogen circulation device 30 circulates hydrogen H ２ The device includes a first tank 32, a second tank 34, and a compressor 36.

[0021] Hydrogen H in generator 4 ２ If the pressure P is greater than the first reference value Pref1, the generator 4 generates excess hydrogen H ２ can be collected in the first tank 32. ２ As will be described later with reference to FIG. 3, the recovery of excess hydrogen H is performed by opening the valves V6 and V7 on the hydrogen recovery lines (lines 40 and 41) connecting the generator 4 and the first tank 32. ２ is recovered in the first tank 32 via the hydrogen recovery line, so that it does not need to be released into the atmosphere.

[0022] The first tank 32 is for storing hydrogen H ２ Since the pressure is set to a pressure (for example, atmospheric pressure) that is sufficiently lower than the pressure P of the generator 4, the first tank 32 receives hydrogen H ２ Therefore, hydrogen H can be recovered quickly by the generator 4 depending on the operating state of the generator 4. ２ becomes excessive, the excess hydrogen H ２ can be collected in the first tank 32.

[0023] The hydrogen H stored in the first tank 32 ２ The compressor 36 is connected to the first tank 32 via lines 41 and 42, and as will be described later with reference to FIG. 4, the hydrogen H 2 in the first tank 32 can be compressed by opening the valves V7 and V8 on these lines.２ The hydrogen H2 compressed by the compressor 36 is stored in the second tank 34 via lines 43, 44, and 45.

[0024] Hydrogen H stored in the second tank ２ can be supplied to the generator 4 via hydrogen supply lines (lines 45, 42, 41, 40) as needed. ２ When the pressure of the hydrogen tank 34 falls below the second reference value Pref2 and thus deviates from the allowable range, as will be described later with reference to FIG. 5, the valves V8 and V10 on the hydrogen supply line are opened to supply hydrogen H2 from the second tank 34 to the generator 4, thereby preventing hydrogen H2 from being supplied from the outside. ２ This can cover the shortfall without additional supply.

[0025] The hydrogen circulation device 30 supplies hydrogen H ２ The power plant 1 may be provided with a hydrogen supply source 50 for additionally supplying hydrogen H. The hydrogen supply source 50 is a detachable hydrogen cylinder, and is connected to the fuel branch line 33 via a line 46. By providing the hydrogen circulation device 30 as described above, the power plant 1 can circulate hydrogen H ２ If there is a surplus or deficiency in hydrogen, it can be dealt with by recovering or supplying hydrogen between the generator 4 and the power plant. However, even so, the hydrogen H required by the generator 4 is still not enough. ２ When the amount of hydrogen H is insufficient, the valves V5 and V11 are opened to supply additional hydrogen H from the hydrogen supply source 50, as will be described later with reference to FIG. ２ This can be covered by supplying

[0026] The power plant 1 includes a control device 100 for controlling the above-described components. The control device 100 includes, for example, a central processing unit (CPU), a random access memory (RAM), a read-only memory (ROM), and a computer-readable storage medium. A series of processes for implementing various functions is stored in a storage medium, for example, in the form of a program. The CPU reads the program into the RAM and executes information processing and arithmetic operations to implement various functions. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories. In each drawing, the control device 100 is connected to each component of the power plant 1 to be controlled via signal lines, but the connection lines are omitted for simplicity of illustration.

[0027] Next, a method of operating the hydrogen circulation system 30 during normal operation of the power plant 1 having the above configuration will be described. Figure 2 is a flowchart showing a method of operating the hydrogen circulation system during normal operation of the power plant 1 of Figure 1, Figure 3 is a configuration diagram showing an operating state corresponding to step S3 of Figure 2, Figure 4 is a configuration diagram showing an operating state corresponding to step S4 of Figure 2, Figure 5 is a configuration diagram showing an operating state corresponding to step S8 of Figure 2, and Figure 6 is a configuration diagram showing an operating state corresponding to step S11 of Figure 2. Note that the following description will exemplify a case in which the hydrogen circulation system 30 is automatically operated (controlled) by the control device 100, but each of these operations may also be manually operated by an operator.

[0028] First, the control device 100 detects the hydrogen H ２The pressure P of the generator 4 is acquired (step S1), and it is determined whether it is higher than a first reference value Pref1, which is the upper limit of the allowable range (step S2). If it is determined that the pressure P is higher than the first reference value Pref1 (step S2: YES), the control device 100 controls the generator 4 to extract excess hydrogen H ２ In step S3, as shown in FIG. 3, the control device 100 controls the hydrogen circulation device 30 to recover excess hydrogen H from the generator 4 through the hydrogen recovery lines (highlighted lines 40 and 41) by opening the valves V6 and V7. ２ The hydrogen circulation device 30 is controlled so that the hydrogen is recovered in the first tank 32 .

[0029] Thereafter, the hydrogen H recovered in the first tank 32 ２ In step S4, as shown in FIG. 4, the control device 100 opens the valves V7 and V8 to allow the hydrogen H 2 from the first tank 32 to flow through the compressor 36 and be stored in the second tank 34 (step S4). ２ is introduced into the second tank 34 through a compressor 36 .

[0030] Thereafter, the control device 100 detects the hydrogen H ２ The pressure P is acquired again (step S5), and it is determined again whether the pressure P is higher than the first reference value Pref1 (step S5). As a result, if it is determined that the pressure P is equal to or lower than the first reference value Pref1 (step S5: NO), the process returns to step S1, and the series of processes are repeated. On the other hand, if it is determined that the pressure P is still higher than the first reference value Pref1 (step S6: YES), the process returns to step S3, and the hydrogen H ２ is recovered in the first tank 32. In this case, the amount of hydrogen consumed in the generator 4 can be reduced.

[0031] On the other hand, if it is determined that the pressure P is equal to or lower than the first reference value Pref1, which is the upper limit of the allowable range (step S2: NO), the control device 100 determines whether the pressure P is lower than the second reference value Pref2, which is the lower limit of the allowable range (step S7). If it is determined that the pressure P is lower than the second reference value Pref2 (step S7: YES), the hydrogen circulation device 30 supplies the generator 4 with the shortage of hydrogen H ２ In step S8, as shown in FIG. 5, the control device 100 opens the valves V8 and V10 to supply the generator 4 with the shortage of hydrogen H through the hydrogen supply lines (highlighted lines 45, 44, and 40). ２ The hydrogen circulation device 30 is controlled so that the hydrogen is supplied from the second tank 34 .

[0032] Thereafter, the control device 100 detects the hydrogen H ２ The pressure P is acquired again (step S9), and it is determined again whether the pressure P is lower than the second reference value Pref2 (step S10). As a result, if it is determined that the pressure P is equal to or higher than the second reference value Pref2 (step S10: NO), the process returns to step S1, and the series of processes are repeated. On the other hand, if it is determined that the pressure P is still lower than the second reference value Pref2 (step S10: YES), the shortage of hydrogen H is supplied from the hydrogen supply source 50. ２ In step S11, as shown in FIG. 6, the control device 100 opens the valves V5 and V11 to supply hydrogen H from the hydrogen supply source 50 to the generator 4 via the lines 46 and 40. ２ In this way, the hydrogen H 2 recovered in advance by the hydrogen circulation device 30 is supplied. ２ In this case, only when the shortage of hydrogen from the generator 4 cannot be covered, additional hydrogen is supplied from the hydrogen supply source 50, thereby making it possible to effectively suppress the amount of hydrogen consumed by the hydrogen supply source 50.

[0033] Next, as another method of operating the hydrogen circulation device 30, the hydrogen H supplied to the generator 4 when the power plant 1 is stopped can be ２ carbon dioxide CO ２ and nitrogen N ２7 and 8 are block diagrams showing the operation of the hydrogen circulation system 30 of FIG. 1 in another operating method.

[0034] When the power plant 1 is shut down, the valves V1 and V4 are closed, thereby stopping the supply of fuel to the combustor 8 of the gas turbine 2. In this state, the hydrogen H ２ 7, by opening valves V6 and V7, excess hydrogen H2 that cannot be recovered in the first tank 32 is recovered in the second tank 34 by opening valves V8 and V9. The second tank 34 contains hydrogen H2 compressed by a compressor 36 to a higher pressure than the first tank 32, as described above. ２ By preferentially supplying the hydrogen H2 recovered in the first tank 32 and the second tank 34 to the generator 4, the generator 4 can operate for a while without receiving hydrogen H2 from the hydrogen supply equipment 14, reducing the amount of hydrogen H2 supplied and improving plant efficiency.

[0035] When hydrogen recovery into the first tank 32 and the second tank 34 is started in this manner, as shown in FIG. 8, the generator 4 is supplied with an inert gas (e.g., carbon dioxide gas) for replacement from the inert gas supply source 60. ２ and nitrogen N ２ At this time, the control device 100 opens a valve V12 provided on an inert gas supply line 62 connecting the inert gas supply source 60 and the generator 4, thereby supplying the inert gas to the generator 4, thereby performing replacement.

[0036] As described above, according to each of the above embodiments, hydrogen H ２ If there is an excess of hydrogen, the excess hydrogen H ２ is recovered in the first tank 32. The first tank 32 is in a state of lower pressure than the generator 4, and therefore, the excess hydrogen H ２The hydrogen recovered in the first tank 32 is pressurized by a compressor 36 and then stored in the second tank 34. As a result, pressurized hydrogen H ２ can be supplied to the generator 4.

[0037] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments may be combined as appropriate.

[0038] The contents described in each of the above embodiments can be understood, for example, as follows.

[0039] (1) A hydrogen circulation device according to one aspect is a hydrogen circulation device for circulating hydrogen for cooling a generator, and includes: a hydrogen recovery line for recovering the hydrogen from the generator; a first tank for storing the hydrogen recovered from the hydrogen recovery line; a compressor for compressing the hydrogen stored in the first tank; a second tank for storing the hydrogen compressed by the compressor; and a hydrogen supply line for supplying the hydrogen stored in the second tank to the generator.

[0040] According to the above aspect (1), when there is an excess of hydrogen for cooling in the generator, the excess hydrogen is recovered in the first tank via the hydrogen recovery line. The first tank is at a lower pressure than the hydrogen in the generator, so the excess hydrogen can be quickly recovered by utilizing the pressure difference. The hydrogen recovered in the first tank is pressurized by a compressor and then stored in the second tank. As a result, pressurized hydrogen can be supplied from the second tank to the generator as needed.

[0041] (2) In another aspect, in the aspect (1) above, when the pressure of the hydrogen in the generator is equal to or greater than a predetermined reference value, the hydrogen is recovered from the generator into the first tank via the hydrogen recovery line.

[0042] According to the above aspect (2), when the hydrogen pressure in the generator is equal to or greater than a reference value, excess hydrogen is recovered from the generator into the first tank, thereby effectively preventing an increase in hydrogen leakage caused by excessive hydrogen pressure in the generator and a decrease in efficiency due to an increase in windage loss in the generator.

[0043] (3) In another aspect, in the above aspect (1) or (2), when the pressure of the hydrogen in the generator is less than a predetermined reference value, the hydrogen is supplied from the second tank to the generator via the hydrogen supply line.

[0044] According to the above aspect (3), when the hydrogen pressure in the generator is below a reference value, hydrogen is supplied from the second tank to the generator that is short of hydrogen. This makes it possible to effectively compensate for the shortage of hydrogen pressure in the generator by supplying hydrogen from the second tank.

[0045] (4) In another aspect, in any one of the above aspects (1) to (3), the hydrogen recovery line includes a hydrogen recovery branch line that branches off from the generator so as to recover the hydrogen in the second tank without passing through the first tank.

[0046] According to the above aspect (4), the hydrogen in the generator can be recovered in the second tank via the hydrogen recovery branch line without passing through the first tank. This makes it possible to preferably recover hydrogen from the generator via the hydrogen recovery branch line, for example, when recovering hydrogen from the generator during a relatively long shutdown or maintenance of the generator.

[0047] (5) In another aspect, in any one of the above aspects (1) to (4), a hydrogen supply source is provided connected to the hydrogen supply line.

[0048] According to the above aspect (5), hydrogen can be supplied to the generator from a hydrogen supply source connected to the hydrogen supply line. As a result, if the supply of hydrogen recovered in the first tank or the second tank is insufficient to supply the hydrogen needed by the generator, the shortage of hydrogen can be made up from the hydrogen supply source. In this case, the hydrogen needed by the generator is supplied to the extent possible by the hydrogen recovered in the first tank or the second tank, thereby saving the amount of hydrogen supplied from the hydrogen supply source.

[0049] (6) In another aspect, in any one of the above aspects (1) to (5), the hydrogen supply line is connected to a fuel supply line for supplying the hydrogen as fuel from a hydrogen supply facility to a gas turbine connected to the generator.

[0050] According to the aspect (6) above, in a generator connected to a gas turbine to which hydrogen is supplied as fuel, hydrogen for cooling the generator can be supplied from a fuel supply line to the gas turbine.

[0051] (7) A hydrogen circulation method according to one aspect is a hydrogen circulation method for circulating hydrogen for cooling a generator, comprising: a step of storing the hydrogen recovered from the generator in a first tank; a step of compressing the hydrogen stored in the first tank and storing it in a second tank; and a step of supplying the hydrogen stored in the second tank to the generator.

[0052] According to the above aspect (7), when there is an excess of hydrogen for cooling in the generator, the excess hydrogen is recovered in the first tank via the hydrogen recovery line. The first tank is under a lower pressure than the hydrogen in the generator, so that the excess hydrogen can be quickly recovered by utilizing the pressure difference. The hydrogen recovered in the first tank is pressurized by a compressor and then stored in the second tank. As a result, pressurized hydrogen can be supplied from the second tank to the generator as needed.

[0053] REFERENCE SIGNS LIST 1 Power plant 2 Gas turbine 4 Generator 6 Compressor 8 Combustor 10 Turbine 12 Fuel supply system 14 Hydrogen supply equipment 16 Fuel supply line 18 Gas turbine rotor 20 Generator rotor 22 Generator casing 24 Bearing 26 Seal member 29 Pressure sensor 30 Hydrogen circulation device 32 First tank 34 Second tank 36 Compressor 60 Inert gas supply source 62 Inert gas supply line 100 Control device

Claims

1. A hydrogen circulation device for circulating hydrogen for cooling a generator, comprising: a hydrogen recovery line for recovering the hydrogen from the generator; a first tank for storing the hydrogen recovered from the hydrogen recovery line; a compressor for compressing the hydrogen stored in the first tank; a second tank for storing the hydrogen compressed by the compressor; and a hydrogen supply line for supplying the hydrogen stored in the second tank to the generator.

2. The hydrogen circulation device according to claim 1, configured to recover the hydrogen from the generator into the first tank via the hydrogen recovery line when the pressure of the hydrogen in the generator is equal to or greater than a preset reference value.

3. A hydrogen circulation device as described in claim 1 or 2, configured to supply hydrogen from the second tank to the generator via the hydrogen supply line when the pressure of the hydrogen in the generator is less than a preset reference value.

4. A hydrogen circulation device as described in claim 1 or 2, wherein the hydrogen recovery line includes a hydrogen recovery branch line that branches off from the generator so as to recover the hydrogen in the second tank without passing through the first tank.

5. The hydrogen circulation device according to claim 1 or 2, further comprising a hydrogen supply source connected to the hydrogen supply line.

6. A hydrogen circulation system according to claim 1 or 2, wherein the hydrogen supply line is connected to a fuel supply line for supplying the hydrogen as fuel from a hydrogen supply facility to a gas turbine connected to the generator.

7. A hydrogen circulation method for circulating hydrogen for cooling a generator, comprising the steps of: storing the hydrogen recovered from the generator in a first tank; compressing the hydrogen stored in the first tank and storing it in a second tank; and supplying the hydrogen stored in the second tank to the generator.

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