Hydrogen gas supply method and hydrogen gas supply system

Abstract

To provide a hydrogen gas supply method and a hydrogen gas supply system that enable stable hydrogen compression even at low pressure or high pressure and that have excellent reliability.SOLUTION: In a supply method and a supply system for hydrogen gas, a low pressure compressor 1 and a high pressure compressor 2 for compressing hydrogen gas are provided. Required pressure of a supply destination includes a low pressure region and a high pressure region, and in the supply method, hydrogen gas is supplied to the supply destination in accordance with the required pressure. The low pressure compressor 1 is a piston crank type compressor, and the high pressure compressor 2 is a hydraulic compressor or a diaphragm type compressor. When the required pressure of the supply destination is in the lower pressure region, hydrogen gas compressed by the low pressure compressor 1 is supplied to the supply destination.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hydrogen gas supply method and a hydrogen gas supply system, and more particularly to a hydrogen gas supply method and a hydrogen gas supply system that can stably compress hydrogen at both low and high pressures and satisfy customers' requests for rapid hydrogen filling. [Background technology]

[0002] In recent years, the development of fuel cell vehicles (FCVs) powered by hydrogen gas has progressed, and they are nearing the stage of practical application. Hydrogen gas is supplied to the hydrogen tank of a fuel cell vehicle at a hydrogen filling station, just as gasoline is supplied to a gasoline-powered vehicle at a gas station.

[0003] Some hydrogen stations are on-site, equipped with hydrogen production equipment and supplying hydrogen produced by that equipment, but in order to reduce equipment costs, there are also off-site hydrogen stations that use a cardle containing multiple gas containers (red) as the hydrogen supply source, which produces hydrogen outside the station.

[0004] Patent Document 1 discloses a method in which, when producing high-pressure hydrogen gas, a hydraulic booster compressor is used to increase the pressure to, for example, over 82 MPa and store the pressure in a pressure accumulator, and, when producing medium-pressure hydrogen gas, a hydraulic booster compressor is used to increase the pressure to, for example, 40 MPa and store the pressure in a pressure accumulator. However, hydraulic compressors are mechanisms that drive pistons using the hydraulic force of hydraulic oil, and due to limitations such as sealing of hydraulic oil, the maximum number of cycles is smaller than that of piston crank compressors with a crank mechanism.As a result, compared to piston crank compressors, there is a drawback in that the flow rate per compressor is lower when increasing pressure from low to high.

[0005] Patent Document 2 discloses a method of five-stage compression using a crank-type compressor, specifically, having cylinders extending radially around a crank-type rotary drive unit, each of which has a piston inside, and increasing the pressure from 0.6 MPa to 145.8 MPa through five-stage compression. The piston crank type can compress a large flow rate from low pressure because it can handle a large number of cycles. Hydrogen stations use ultra-high pressure compression of over 80 MPa.

[0006] Patent Document 3 also uses a crank-type compressor at high pressures of 50 MPa or more, and in this type of hydrogen station, a crank-type compressor is sometimes used even at high pressures of 50 MPa or more. However, according to the inventor's investigation, there are concerns that ultra-high pressure compression may result in a shorter lifespan and lower reliability of wear parts compared to low pressure compression. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-139378 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-183684 [Patent Document 3] Japanese Patent Application Publication No. 2023-67967 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, an object of the present invention is to provide a highly reliable hydrogen gas supply method and hydrogen gas supply system that can stably compress hydrogen gas regardless of whether it is at a low pressure or a high pressure. Further objects of the present invention will become apparent from the following description. [Means for solving the problem]

[0009] The above problems are solved by the following inventions.

[0010] 1. It is equipped with a low-pressure compressor and a high-pressure compressor to compress hydrogen gas. A method for supplying hydrogen gas to a supply destination in accordance with a required pressure, the required pressure of which has a low pressure region and a high pressure region, the low-pressure compressor is a piston crank compressor, the high-pressure compressor is a hydraulic compressor or a diaphragm compressor, When the required pressure of the supply destination is in a low-pressure region, the hydrogen gas compressed by the low-pressure compressor is supplied to the supply destination; A method for supplying hydrogen gas, characterized in that, when the required pressure of the supply destination is in the high-pressure region, hydrogen gas is compressed by the low-pressure compressor, the compressed hydrogen gas is introduced into the high-pressure compressor, and the hydrogen gas compressed by the high-pressure compressor is supplied to the supply destination. 2. 2. The method for supplying hydrogen gas according to item 1, wherein the destination of the supply of hydrogen gas is a pressure accumulator at a hydrogen station or a hydrogen storage tank of a mobile body. 3. The hydrogen gas supply method described in item 3 above, characterized in that the method of filling the hydrogen storage tank is a direct filling method from the compressor or a differential pressure filling method from the accumulator, or both the direct filling method and the differential pressure filling method. 4. The hydrogen gas supply method described in item 1, wherein the low-pressure region of the required pressure at the supply destination is a region where the upper limit value is any value between 40 and 50 MPa, and the high-pressure region is a region where the upper limit value of the low-pressure region is any value greater than the upper limit value of the low-pressure region and is not greater than 100 MPa. 5. 2. The method for supplying hydrogen gas according to item 1, wherein the piston crank compressor and the hydraulic compressor or the diaphragm compressor share a common electric motor. 6. 7. The method for supplying hydrogen gas according to item 6 above, further comprising providing a clutch for controlling ON / OFF of the drive of the hydraulic compressor or diaphragm compressor. 7. The hydrogen gas supply method described in 1 above is characterized in that the piston crank compressor and the hydraulic compressor or diaphragm compressor are mounted together, and common auxiliary equipment is shared to form a unit of a size that can fit on the same skid. 8. The hydrogen gas flow rate that can be supplied to the destination is 400 Nm 3 / Hr~1200Nm 3 2. The method for supplying hydrogen gas according to item 1, wherein the hydrogen gas supply rate is 1 / Hr. 9. It is equipped with a low-pressure compressor and a high-pressure compressor to compress hydrogen gas. A hydrogen gas supply system in which the required pressure of a supply destination has a low-pressure region and a high-pressure region, and hydrogen gas is supplied to the supply destination in accordance with the required pressure, the low-pressure compressor is a piston crank compressor, the high-pressure compressor is a hydraulic compressor or a diaphragm compressor, When the required pressure of the supply destination is in the low-pressure region, the hydrogen gas compressed by the low-pressure compressor is supplied to the supply destination; A hydrogen gas supply system characterized in that, when the required pressure at the supply destination is in the high-pressure region, hydrogen gas is compressed by the low-pressure compressor, the compressed hydrogen gas is introduced into the high-pressure compressor, and the hydrogen gas compressed by the high-pressure compressor is supplied to the supply destination. 10. 10. The hydrogen gas supply system according to item 9, wherein the destination of the hydrogen gas supply is a pressure accumulator at a hydrogen station or a hydrogen storage tank of a mobile body. 11. The hydrogen gas supply system described in item 10, characterized in that the method of filling the hydrogen storage tank is a direct filling method from the compressor, a differential pressure filling method via the accumulator, or a combination of the direct filling method and the differential pressure filling method. 12. The hydrogen gas supply system described in paragraph 9 is characterized in that the low-pressure region of the required pressure at the supply destination is a region where the upper limit value is any value between 40 and 50 MPa, and the high-pressure region is a region that is greater than any value of the upper limit value of the low-pressure region and is not more than 100 MPa. 13. The hydrogen gas supply system of claim 9, wherein the piston crank compressor and the hydraulic compressor or the diaphragm compressor share an electric motor. 14. 14. The hydrogen gas supply system according to claim 13, further comprising a clutch for controlling ON / OFF of the hydraulic compressor or diaphragm compressor. 15. The hydrogen gas supply system described in item 9 is characterized in that the piston crank compressor and the hydraulic compressor or diaphragm compressor are mounted together and common auxiliary equipment is shared, forming a compressor unit of a size that can fit on the same skid. 16. The hydrogen gas flow rate that can be supplied to the destination is 400 Nm 3 / Hr~1200Nm 3 10. The hydrogen gas supply system according to item 9, characterized in that the hydrogen gas supply rate is / Hr. 17. a motor pulley (102) provided on a drive shaft (101) of the electric motor (100); a piston crank compressor pulley (103) provided on a piston crank compressor side drive shaft (107) of the piston crank compressor (1); a hydraulic compressor pulley (105) provided on a hydraulic compressor-side drive shaft (108) of the hydraulic compressor (2); The electric motor pulley (102) and the piston crank compressor pulley (103) are rotatably connected via a piston crank compressor belt (104), The electric motor pulley (102) and the hydraulic compressor pulley (105) are rotatably connected via a hydraulic compressor belt (106), The piston crank compressor (1) has a structure in which the rotation of a drive shaft driven by an electric motor is converted into linear reciprocating motion of a piston via a crankshaft, thereby compressing hydrogen gas filled above the piston in a cylinder, and The hydraulic compressor (2) is configured such that the rotation of the drive shaft by the drive of an electric motor converts the hydraulic pressure generated by driving a hydraulic pump into reciprocating piston motion, and the reciprocating piston motion compresses the hydrogen gas filled in the cylinder, thereby providing a hydrogen gas supply system as described in item 9. 18. a piping system (110) that passes through the low-pressure compression of the piston crank compressor (1) to reach the suction side of the hydraulic compressor (2) that compresses high-pressure hydrogen and then reaches the hydraulic compressor (2); and a branch piping system (111) that passes through the piston crank compressor (1) but does not enter the suction side of the hydraulic compressor (2) and bypasses the hydraulic compressor (2) to reach the discharge side of the hydraulic compressor (2), a control valve (112) for controlling opening and closing of the branch piping system (111); a clutch (109) for disconnecting the driving force of the electric motor (105) of the hydraulic compressor (2) from the drive shaft (108) of the hydraulic compressor (2); When the required pressure of the hydrogen storage tank is equal to or lower than a set value, the clutch (109) is disengaged and the control valve (112) is opened. 11. The hydrogen gas supply system according to claim 10, wherein when the required pressure of the hydrogen storage tank exceeds the set value, the clutch (109) is engaged and the control valve (112) is closed. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a highly reliable hydrogen gas supply method and hydrogen gas supply system that can stably compress hydrogen regardless of whether it is at a low pressure or a high pressure.

[0012] Furthermore, the present invention can provide a hydrogen gas supply method and a hydrogen gas supply system that enable stable, large-volume hydrogen filling at hydrogen stations and that also provides excellent customer satisfaction. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic side view showing an example of a hydrogen station to which the present invention is preferably applied, showing a direct charging system. [Figure 2] FIG. 1 is a schematic side view showing another example of a hydrogen station to which the present invention is preferably applied, showing a differential pressure filling system. [Figure 3] Schematic cross-sectional view showing an example of a piston crank compressor [Figure 4] Schematic cross-sectional view showing an example of a hydraulic compressor [Figure 5] Schematic cross-sectional view showing an example of a diaphragm compressor [Figure 6] FIG. 1 is a diagram illustrating an embodiment in which a low-pressure hydrogen compressor and a high-pressure hydrogen compressor share a motor. [Figure 7] FIG. 1 is a diagram illustrating an embodiment in which a low-pressure hydrogen compressor and a high-pressure hydrogen compressor share a motor. [Figure 8] FIG. 1 is a diagram showing an example of a control flow for starting a compressor in a hydrogen gas supply system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present invention will now be described. 1 and 2 are schematic side views showing an example of a hydrogen station to which the present invention is preferably applied, with the example of FIG. 1 showing a direct filling method and the example of FIG. 2 showing a differential pressure filling method.

[0015] Explaining based on Figs. 1 and 2, the compressor includes a piston crank compressor 1 which is a low-pressure hydrogen compressor, and a hydraulic compressor 2 which is a high-pressure hydrogen compressor.

[0016] FIG. 1 shows an example of a direct filling method in which hydrogen gas produced by compression using a low-pressure hydrogen compressor 1 and a high-pressure hydrogen compressor 2 is filled into a hydrogen storage tank of a mobile object 4 via a dispenser 3.

[0017] Figure 2 shows an example of a differential pressure filling method in which hydrogen gas produced by compression using a compressor is first supplied to a pressure accumulator 5, and then filled from the pressure accumulator 5 into the hydrogen storage tank of a mobile object 4 via a dispenser 3.

[0018] As shown in FIGS. 1 and 2, hydrogen gas supplied from the compressor is supplied to a pressure accumulator 5 in a hydrogen station or a hydrogen storage tank in a mobile object 4. Hydrogen gas can be filled into the hydrogen storage tank of the mobile object 4 by a direct filling method in which hydrogen is filled from a compressor via a dispenser 3 as shown in Figure 1, or a differential pressure filling method in which hydrogen is supplied from a compressor to a pressure accumulator 5 and then filled from the pressure accumulator 5 via a dispenser 3 as shown in Figure 2, or by a combination of the direct filling method and the differential pressure filling method.

[0019] In this embodiment, an example is shown in which hydrogen gas, which serves as fuel at a hydrogen station, is supplied from a compressor to the destination, which is a pressure accumulator 5 or a hydrogen storage tank of a mobile object 4, but this is not limited to this, and the destination of the hydrogen gas is not limited to a hydrogen station; the hydrogen gas can also be compressed and supplied to a storage tank for hydrogen transportation. Hereinafter, the hydrogen gas supply method and system of the present invention will be described taking as an example a case where the destination of the supply of hydrogen gas as fuel is a hydrogen storage tank.

[0020] In the hydrogen gas supply method and supply system of the present invention, while the required or required hydrogen gas pressure in the hydrogen storage tank is in the low-pressure range (for example, about 0 to 50 MPa), the crank compressor is driven to produce low-pressure compressed hydrogen and supply it to the hydrogen storage tank. As hydrogen gas is supplied into the tank and the volume of hydrogen in the tank increases, the pressure inside the tank increases, and accordingly the required pressure of the hydrogen storage tank also increases. In other words, the required pressure of the tank fluctuates depending on the pressure inside the tank, which fluctuates depending on the volume of hydrogen gas inside the tank, and the more hydrogen gas is supplied to the tank, the higher the required pressure of the tank becomes.

[0021] In the present invention, the required pressure of the supply destination is divided into two regions, a low-pressure region and a high-pressure region, and in the low-pressure region, the pressure of the hydrogen gas compressed by the low-pressure compressor is sufficient to supply the hydrogen gas to the supply destination, so there is no need to start the high-pressure compressor.

[0022] In this specification, when the required pressure at the supply destination is in the low-pressure region, supplying hydrogen gas compressed by the low-pressure compressor to the supply destination means that the pressure of the hydrogen gas compressed by the low-pressure compressor is sufficient to supply it to the supply destination, and therefore there is no need to perform compression processing using a high-pressure compressor.

[0023] "No compression process in the high-pressure compressor" includes introducing hydrogen gas into the high-pressure compressor and allowing the hydrogen gas to flow through the high-pressure compressor without substantially increasing the pressure. "No compression process in the high-pressure compressor" also includes using the hydrogen gas introduced into the high-pressure compressor as a flow path through the high-pressure compressor without undergoing compression. "No compression process in the high-pressure compressor" also includes switching the flow path without introducing the hydrogen gas into the high-pressure compressor using a control valve, which will be described later.

[0024] In this embodiment, when the required pressure of the supply destination is in the low-pressure region and has not yet reached the high-pressure region, hydrogen can be supplied as long as the pressure of the hydrogen supplied from the compressor is even slightly higher than the required pressure of the supply destination. This means that hydrogen gas can be supplied to the supply destination without being compressed by the high-pressure compressor. Therefore, in this case, only the low-pressure compressor is operated, and the high-pressure compressor is not operated (the clutch described below is disengaged, leaving the driving force not being transmitted). This prevents the high-pressure compressor from operating, which has the effect of significantly reducing electricity costs. Furthermore, by not operating the high-pressure compressor, sliding parts such as the piston of the high-pressure compressor can be stopped, which has the effect of reducing wear.

[0025] On the other hand, in the high-pressure region, the pressure of the hydrogen gas compressed by the low-pressure compressor is insufficient to supply the hydrogen gas to the destination, so the hydrogen gas is not filled at the destination. For this reason, by introducing the hydrogen gas compressed by the low-pressure compressor into the high-pressure compressor and compressing it with the high-pressure compressor, it is possible to raise the pressure to a level at which the hydrogen gas can be supplied to the destination, even in the high-pressure region.

[0026] When the hydrogen gas pressure in the hydrogen storage tank to which the hydrogen is to be supplied is in the high-pressure range (for example, about 50 to 100 MPa), the hydrogen gas is compressed to a pressure of 50 MPa by operating the low-pressure compressor, and then the high-pressure compressor is operated by operating the electric motor of the high-pressure compressor or by engaging the clutch, and the hydrogen gas that has reached a pressure of 50 MPa in the low-pressure compressor is further compressed and supplied to the hydrogen storage tank to which the hydrogen is to be supplied.

[0027] In the present invention, depending on the required pressure of the hydrogen storage tank, if the required pressure is in the low pressure range, the piston crank compressor is driven to compress the hydrogen, and the hydrogen gas is filled into the hydrogen storage tank as the supply destination without driving the hydraulic compressor or diaphragm compressor. Next, when the required pressure exceeds the low-pressure region and reaches the high-pressure region, the electric motor of the high-pressure compressor is operated (the clutch is engaged and driving force is transmitted to the high-pressure compressor), the hydrogen gas is compressed by the low-pressure compressor, and the hydrogen gas compressed by the low-pressure compressor is introduced into the high-pressure compressor, which then compresses the hydrogen gas so that its pressure exceeds the required pressure of the supply destination and fills it.

[0028] The piston crank compressor 1 used as the low-pressure compressor may have a plurality of compression stages, preferably three or four stages, for example. The hydraulic compressor 2 used as the high-pressure compressor may be a single-stage or two-stage compressor. The total number of stages in the compressor including the low-pressure compressor and the high-pressure compressor may be five stages or about six to eight stages.

[0029] In the present invention, the upper limit of the low-pressure region of the hydrogen gas pressure in the hydrogen storage tank is preferably 40 to 50 MPa. This upper limit varies depending on the design value of the compression capacity of the low-pressure compressor. The upper limit of the low-pressure region in the present invention is approximately equal to the upper limit of the pressure of hydrogen gas that can be compressed by the low-pressure compressor. On the other hand, the high pressure region of the hydrogen gas pressure in the hydrogen storage tank is preferably a region that is higher than the upper limit of the low pressure region and is equal to or lower than 100 MPa. In this embodiment, the low pressure region has an upper limit of any value in the range of 40 to 50 MPa, and the high pressure region has a lower limit of a value greater than the upper limit of the low pressure region, with an upper limit of up to 100 MPa.

[0030] The gas pressure of low-pressure hydrogen compression in the low-pressure hydrogen compressor 1 is in the range of 0.6 to 50 MPa, and the upper limit of the gas pressure of high-pressure compression in the high-pressure hydrogen compressor 2 is in the range of 100 MPa. As described above, the low-pressure hydrogen compressor 1 increases the gas pressure in multiple stages, and by designing the pressure increase ratio according to the number of stages, it is possible to increase the gas pressure to any desired level. In this embodiment, the high-pressure hydrogen compressor 2 is a compressor that further increases the pressure and supplies hydrogen when the pressure supplied by the low-pressure hydrogen compressor 1 is insufficient, for example, when the required pressure (demanded pressure) at the supply destination falls into the high-pressure range. Therefore, the lower limit of the gas pressure of high-pressure compression in the high-pressure hydrogen compressor 2 varies depending on the upper limit of the low-pressure hydrogen compressor 1.

[0031] The hydrogen gas flow rate that can be supplied to the hydrogen storage tank is 400 to 1200 Nm3 under standard conditions for the entire compressor. 3 / Hr. According to the present invention, even if 3 to 8 moving objects such as automobiles enter a hydrogen station at the same time and request hydrogen filling, the large hydrogen gas flow rate that can be filled allows for smooth filling without congestion, making it possible to provide a system with excellent practicality.

[0032] The hydrogen to be compressed is usually brought to the hydrogen station in a curdle (a container containing hydrogen produced outside and multiple gas containers (red)). In addition to curdles, hydrogen can also be supplied to the hydrogen station via pipelines.

[0033] Hydrogen is produced outside and brought to the hydrogen station in gaseous form, but it may also be liquefied hydrogen. It is also possible to install a hydrogen production device at the hydrogen station and use the hydrogen produced by that device. Examples of hydrogen production devices include a device that produces hydrogen gas by installing a water electrolyzer and using an external power source, a hydrocarbon fuel cracking device, and a device that produces hydrogen gas by installing a liquefied hydrogen storage container filled with liquefied hydrogen and using a vaporizer.

[0034] In the hydrogen gas supply method and system of the present invention, the mobile object 4 may be a fuel cell vehicle or a ship that uses hydrogen as fuel. The present invention is advantageous in that it can supply a large amount of hydrogen gas and is therefore suitable for use in large-capacity tanks for buses and trucks.

[0035] Furthermore, the hydrogen gas supply system that realizes the hydrogen gas supply method of the present invention is small enough to fit on the same skid. The size that can fit on the same skid is, for example, the size that can fit in a 20-foot container, and specifically, the size of the floor area inside a 20-foot container is exemplified, but is not limited to this. The hydrogen station in which the present invention is installed is not limited to a land-based one, but may be an offshore one, and may be either a fixed type or a mobile type.

[0036] FIG. 3 is a schematic cross-sectional view showing an example of a piston crank compressor. In Figure 3, a piston 11 is provided inside a cylinder 10, and a piston ring 12 is provided to prevent leakage from the outer periphery of the piston 11 to some extent. Multiple piston rings 12 can be provided. In the example shown, two rings are provided. The lower part of the piston 11 is supported by a piston rod 13. The piston rod 13 is connected to a crankshaft 15 via a connecting rod 14.

[0037] The crankshaft 15 is rotatably connected to a compressor motor (not shown), and the rotation of the motor rotates the crankshaft 15, which converts the rotation into linear reciprocating motion, causing the piston rod 13 to move up and down.

[0038] When the crankshaft 15 rotates, the piston rod 13 moves up and down, and the piston 11 moves up and down accordingly, so that the hydrogen gas filled above the piston 11 is compressed.

[0039] FIG. 4 is a schematic cross-sectional view showing an example of a hydraulic compressor. In FIG. 4, pressure of oil working fluid 16 is applied from below to a piston 11 equipped with a piston seal 16 provided in a cylinder 10. The oil working fluid 16 is sent from a hydraulic pump 170 , and the pumping pressure of the hydraulic pump 170 presses the piston 11 upward, compressing the hydrogen gas filled above the piston 11 in the cylinder 10 .

[0040] The hydraulic pump 170 has two gears 172 and 173 that mesh with each other in a casing 171 so that their outer surfaces are in contact with each other. The gear 172 is a driving gear, and the gear 173 is a driven gear.

[0041] When the meshing parts separate due to rotation, a space is created, and oil is sucked in. In this way, the space is filled with oil. The oil is guided along the inner surface 175 of the casing 171 to the discharge side 176. The meshing parts separate the suction side 177 and the discharge side 176.

[0042] The drive gear 172 is configured to be rotatable by a rotary shaft connected to an electric motor (not shown). When the drive gear 172 of the illustrated gear pump 170 rotates, the oil pushed out from the gear pump 172 presses the working fluid 17 shown in FIG.

[0043] Pressure is applied to the oil working fluid 17 from below the piston 11 equipped with a piston seal 16 provided in the cylinder 10. In this way, the oil working fluid 17 presses the piston 11 upward by the pump pressure of the gear pump 172, which is a hydraulic pump, and compresses the hydrogen gas filled above the piston 11 in the cylinder 10.

[0044] In the case of a mechanical drive without oil working fluid, there is no object for leakage into the cylinder 10, so there is no risk of leakage from the piston ring 12 shown in Figure 3. As a result, the load is not as large as with a hydraulic system, so the piston speed can be increased. On the other hand, in the case of a hydraulic system, it is necessary to prevent leakage of the oil working fluid 17 to the process side, so it is preferable to select a piston seal 16 with strong sealing properties. As a result, it is preferable to keep the piston speed low to prevent wear and damage to the piston seal 16.

[0045] In the illustrated example, the oil working fluid is pressurized using a gear pump, and the pressurized oil working fluid pressurizes a piston upward, thereby compressing hydrogen gas. However, any form can be used as long as pressure can be applied to the oil working fluid using the power of the electric motor via the drive shaft, and the present invention is not limited to a gear pump as in the illustrated example.

[0046] Also, a booster type hydraulic compressor that does not use a hydraulic pump that directly applies oil working fluid can be used. This booster type hydraulic compressor applies pressure from an oil working fluid pressurized by compressed air from below the piston, causing the piston to reciprocate and compress the hydrogen gas filled above the piston in the cylinder. In this case, the air used to compress the oil working fluid can be compressed by transmitting power from an electric motor via a drive shaft.

[0047] FIG. 5 is a schematic cross-sectional view showing an example of a diaphragm compressor. In FIG. 5, the piston rod 13 supporting the diaphragm 18 is reciprocated (moved up and down) to cause the diaphragm 18 to reciprocate (move up and down), thereby compressing the hydrogen gas filled above the diaphragm 18 in the cylinder 10. This compressor compresses air by moving a metal membrane called a diaphragm up and down to change the volume. It has the advantage of not having any sliding parts like a piston and therefore no lifespan due to wear. On the other hand, diaphragm compressors have a limited fatigue lifespan because the volume changes due to the elastic deformation of the diaphragm 18.

[0048] In the present invention, low pressure compression and high pressure compression are performed using different types of compressors. Hydraulic compressors have a mechanism that drives pistons using the hydraulic force of hydraulic oil, and due to restrictions such as sealing of hydraulic oil, the maximum number of cycles is smaller than that of piston crank compressors with a crank mechanism.As a result, compared to piston crank compressors, they have the characteristic of having a smaller flow rate per compressor when increasing pressure from low to high.

[0049] However, the piston crank type can compress a large flow rate when compressing from a low pressure because it can have a large number of cycles. At hydrogen stations, ultra-high pressure compression of over 80 MPa is achieved using a piston crank compressor. When piston crank compressors are used to compress low pressures of 50 MPa or less, there are concerns that the lifespan and reliability of wear parts will be reduced when they are used to compress high pressures of 50 MPa or more. In contrast, hydraulic compressors are superior in that they do not have the above problems in the high pressure and ultra-high pressure ranges. Therefore, the present invention takes advantage of the features of both and provides a hydrogen gas supply method and system that has a high flow rate, is highly reliable, and is highly practical by placing a crank-type compressor in the front stage and a hydraulic compressor or diaphragm-type compressor in the rear stage.

[0050] Next, an embodiment in which the low-pressure hydrogen compressor (piston crank compressor) and the high-pressure hydrogen compressor (hydraulic compressor) share an electric motor will be described with reference to FIGS. Sharing an electric motor means that instead of providing separate electric motors for the low-pressure and high-pressure hydrogen compressors, only one electric motor is provided to drive both the low-pressure and high-pressure hydrogen compressors and perform low-pressure and high-pressure hydrogen compression. Since the low-pressure hydrogen compressor is a piston crank compressor and the high-pressure hydrogen compressor is a hydraulic compressor or a diaphragm compressor, sharing an electric motor means that instead of providing separate electric motors for the piston crank compressor and the hydraulic compressor, only one electric motor is provided to drive both the piston crank compressor and the hydraulic compressor and compress both low-pressure and high-pressure hydrogen. Furthermore, when we say that an electric motor is shared, it means that instead of providing separate electric motors for the piston crank compressor and the diaphragm compressor, only one electric motor is provided to drive both the piston crank compressor and the diaphragm compressor, thereby compressing low-pressure hydrogen and high-pressure hydrogen.

[0051] A specific structure in the case where the electric motor is shared will be described with reference to FIGS. 6 and 7. FIG. As shown in FIGS. 6 and 7, a motor pulley 102 is provided on a drive shaft 101 of an electric motor 100, and the motor pulley 102 can also rotate as the drive shaft rotates.

[0052] The electric motor pulley 102 and the low-pressure hydrogen compressor pulley (piston crank compressor pulley) 103 are connected via the low-pressure hydrogen compressor belt (piston crank compressor belt) 104, and the low-pressure hydrogen compressor pulley 103 is connected to the low-pressure hydrogen compressor side drive shaft (piston crank compressor side drive shaft) 107.

[0053] In addition, the electric motor pulley 102 and the high-pressure hydrogen compressor pulley (hydraulic compressor pulley) 105 are connected via a high-pressure hydrogen compressor belt (hydraulic compressor belt) 106, and the high-pressure hydrogen compressor pulley 105 is connected to a high-pressure hydrogen compressor side drive shaft (hydraulic compressor side drive shaft) 108.

[0054] The crank piston compressor 1 is configured to be driven by the rotation of the low-pressure hydrogen compressor side drive shaft 107 .

[0055] The hydraulic compressor 2 is configured such that, when the high-pressure hydrogen compressor side drive shaft 108 is rotationally driven, the gear 172 (see Figure 4) connected to the high-pressure hydrogen compressor side drive shaft 108 is rotationally driven, thereby pressurizing the oil working fluid.

[0056] In this embodiment, the high-pressure hydrogen compressor 2 can be a diaphragm compressor instead of a hydraulic compressor. In this case, the piston rod 13 (see Figure 5) is connected to the high-pressure hydrogen compressor side drive shaft 108, and the rotational drive of the high-pressure hydrogen compressor side drive shaft 108 is converted into reciprocating motion of the piston rod, thereby driving the diaphragm 18 (see Figure 5).

[0057] In the illustrated example, the low-pressure hydrogen compressor 1 performs four-stage compression, but in this embodiment, although not shown, a return pipe for adjusting the hydrogen gas flow rate can also be provided from each stage of the low-pressure hydrogen compressor 1. The high-pressure hydrogen compressor 2 may also be provided with a return pipe for adjusting the hydrogen gas flow rate.

[0058] In the illustrated example, the low-pressure hydrogen compressor 1 performs four-stage compression, but in this embodiment, although not shown, a return pipe for adjusting the hydrogen gas flow rate can also be provided from each stage of the low-pressure hydrogen compressor 1. The high-pressure hydrogen compressor 2 may also be provided with a return pipe for adjusting the hydrogen gas flow rate.

[0059] The high-pressure hydrogen compressor side drive shaft 108 is provided with a clutch 109 that enables disconnection of the driving force of the electric motor 100. In other words, the driving force of the electric motor 100 can be controlled by the clutch 109 by ON / OFF control.

[0060] The hydrogen passes through low-pressure compression in the low-pressure hydrogen compressor 1 and reaches a piping system 110 on the suction side of the high-pressure hydrogen compressor 2 . In this embodiment, a branch piping system 111 is provided that bypasses the high-pressure hydrogen compressor 2 and reaches the discharge side of the high-pressure hydrogen compressor 2 without entering the suction side of the high-pressure hydrogen compressor 2 via the low-pressure compression of the low-pressure hydrogen compressor 1. The branch piping system 111 is provided with a control valve 112 that controls opening and closing.

[0061] A pressure sensor 113 is provided near the hydrogen gas discharge portion of the compressor, and is configured to be able to detect the discharge pressure.

[0062] FIG. 6 shows a state in which clutch 109 is engaged. When electric motor 100 is driven, drive shaft 101 is rotated, and the rotation of rotary shaft 101 rotates low-pressure hydrogen compressor side drive shaft 107, which is converted into linear reciprocating motion of the piston via the crankshaft, compressing the hydrogen gas filled above the piston in the cylinder. At this time, since the control valve 112 provided in the branch piping system 111 is closed, the hydrogen gas compressed by the low-pressure hydrogen compressor 1 is introduced into the piping system 110 leading to the high-pressure hydrogen compressor 2 . Since the high-pressure hydrogen compressor 2 is connected to a clutch 109, the rotation of the drive shaft 101 of the electric motor 100 rotates the high-pressure hydrogen compressor side drive shaft 108, thereby discharging high-pressure hydrogen gas compressed by the high-pressure hydrogen compressor 2.

[0063] FIG. 7 shows the state in which the clutch 109 is disengaged. When the electric motor 100 is driven, the drive shaft 101 is rotated, and the rotation of the drive shaft 101 rotates the low-pressure hydrogen compressor side drive shaft 107, which is converted into linear reciprocating motion of the piston via the crankshaft, compressing the hydrogen gas filled above the piston in the cylinder. At this time, since the control valve 112 provided in the branch piping system 111 is open, the hydrogen gas compressed by the low-pressure hydrogen compressor 1 bypasses the high-pressure hydrogen compressor 2 without entering the piping system 110 leading to the high-pressure hydrogen compressor 2, is introduced into the branch piping system 111, and reaches the line on the discharge side of the high-pressure hydrogen compressor 2. In this way, the low-pressure hydrogen gas compressed by the low-pressure hydrogen compressor 1 can be discharged without starting the high-pressure hydrogen compressor 2.

[0064] As described above, the electric motor 100 can be shared by both the low-pressure hydrogen compressor 1 and the high-pressure hydrogen compressor 2, which eliminates the need for an electric motor installed in each compressor, thereby not only reducing installation space but also simplifying control, thereby reducing the need for a control panel and electrical and control wiring.

[0065] In addition, a clutch 109 is provided on the high-pressure hydrogen compressor side drive shaft 108 connected to the shared electric motor 100, so that when there is no need to drive the high-pressure hydrogen compressor 2, the clutch 109 can be used to disconnect the high-pressure hydrogen compressor 2 from the electric motor 100, preventing the high-pressure hydrogen compressor 2 from being driven. This shortens the actual operating time of the high-pressure hydrogen compressor 2, which in turn extends the maintenance period for the high-pressure hydrogen compressor 2. As a result, the service life of the high-pressure hydrogen compressor 2 is extended, and the service life of the entire compressor can be extended to the service life of the low-pressure hydrogen compressor 1.

[0066] Furthermore, it is possible to share auxiliary equipment, including the cooling fans that cool the refrigerant used to cool the hydrogen gas used in the two types of compressors, which makes it possible to significantly reduce installation space.

[0067] In the examples of FIGS. 6 and 7, the low-pressure hydrogen compressor 1 performs four-stage compression, and the high-pressure hydrogen compressor 2 performs one-stage compression, but the present invention is not limited to this. Although not shown, a system has been constructed that allows the hydrogen gas compressed at each stage to exchange heat with a refrigerant for cooling, and a system has been constructed in which the refrigerant is centralized so that it is cooled by a single cooling fan (not shown).This allows one cooling fan to be shared by both the low-pressure hydrogen compressor 1 and the high-pressure hydrogen compressor 2, significantly reducing the installation space.

[0068] In this way, it is possible to significantly reduce the installation space, and the compressor unit can be formed to fit into a 20ft container.

[0069] The control flow of the system of this embodiment will be described with reference to Fig. 8. Here, the example of hydrogen supply by the direct filling method shown in Fig. 1 will be described.

[0070] First, when the dispenser is connected to the hydrogen storage tank of the mobile body, the required pressure of the hydrogen storage tank is detected (S1).

[0071] Next, it is determined whether the required pressure exceeds a predetermined set value (S2), where the predetermined set value is a pressure that has been set in advance.

[0072] In this embodiment, an example will be described in which compression is performed in a total of five stages, for example, with four low-pressure hydrogen compressors and one high-pressure hydrogen compressor. In this case, if the high-pressure discharge pressure is 90 MPa and the suction pressure is 3 MPa, a 30-fold increase is required to increase the pressure from 3 MPa to 90 MPa. If the 30-fold increase is achieved in five stages, and each stage is increased at the same pressure, the increase is 1.98 times per stage.

[0073] If the suction pressure is 3 MPa and the pressure is increased by a constant factor of 1.98, the first stage discharge pressure will be approximately 5.9 MPa, the second stage discharge pressure will be approximately 11.6 MPa, the third stage discharge pressure will be approximately 22.9 MPa, the fourth stage discharge pressure will be approximately 45.2 MPa, and the fifth stage discharge pressure will be approximately 90 MPa.

[0074] In this way, by determining the suction pressure and the target discharge pressure in the design, the pressure increase ratio of each stage can be determined in the design. Therefore, by setting the set pressure to a value equal to or close to the discharge pressure of the final stage of the low-pressure hydrogen compressor 1 in the determined multiple stages, it is possible to determine whether or not to compress the hydrogen using the high-pressure hydrogen compressor 2 described below in relation to the required pressure (necessary pressure) of the compressor's supply destination.

[0075] If the required pressure is equal to or lower than the predetermined set value (NO in S2), the required pressure is lower than the set value (set pressure), so the clutch 109 of the high-pressure hydrogen compressor 2 is disengaged (clutch open) (S3), the control valve 112 is opened (S4), the electric motor 100 is started, and the compressor is started (S7). In this case, because the clutch 109 is disengaged, only the low-pressure hydrogen compressor 1 is started, and the high-pressure hydrogen compressor 2 is not started.

[0076] On the other hand, if the required pressure is greater than the predetermined set value (YES in S2), the required pressure is higher than the set value (set pressure), so the clutch 109 of the high-pressure hydrogen compressor 2 is engaged (clutch closed) (S5), the control valve 112 is closed (S6), the electric motor 100 is started, and the compressor is started (S7). In this case, because the clutch 109 is engaged, both the low-pressure hydrogen compressor 1 and the high-pressure hydrogen compressor 2 are started.

[0077] Next, when a predetermined condition for transmitting a stop signal is met, a stop signal process is performed to transmit a stop signal (S8). The predetermined conditions for the stop signal processing include, for example, pressing an emergency stop button, completion of hydrogen supply, etc. Other conditions may include detection of mechanical failure, etc., and are not limited to these, and are preferably determined taking safety and reliability into consideration.

[0078] Next, it is determined whether or not a stop signal is present (S9). If a stop signal is present, the compressor operation is stopped (S10). If a stop signal is not present, the process returns to detecting the required pressure (S1) and continues processing until a stop signal is present.

[0079] The above-described embodiments are merely examples and are not intended to limit the scope of the invention. Various other embodiments are possible, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Such embodiments and modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the claims and their equivalents. [Explanation of symbols]

[0080] 1: Low-pressure hydrogen compressor 2: High-pressure hydrogen compressor 3: Dispenser 4: Moving object 5: Pressure accumulator 10: Cylinder 11: Piston 12: Piston ring 13: Piston rod 14:Joining rod 15: Crankshaft 16: Piston seal 17: Oil hydraulic fluid 18: Diaphragm 100: Electric motor 101: Drive shaft 102: Electric motor pulley 103: Pulley for low-pressure hydrogen compressor (pulley for piston crank compressor) 104: Belt for low-pressure hydrogen compressor (belt for piston crank compressor) 105: Pulley for high-pressure hydrogen compressor (pulley for hydraulic compressor) 106: High-pressure hydrogen compressor belt (hydraulic compressor belt) 107: Low-pressure hydrogen compressor drive shaft (piston crank compressor drive shaft) 108: High-pressure hydrogen compressor drive shaft (hydraulic compressor drive shaft) 109: Clutch 110: Piping system 111: Branch piping system 112: Control valve 113: Pressure sensor

Claims

1. It is equipped with a low-pressure compressor and a high-pressure compressor to compress hydrogen gas. A method for supplying hydrogen gas to a supply destination in accordance with a required pressure, the required pressure of which has a low pressure region and a high pressure region, the low-pressure compressor is a piston crank compressor, the high-pressure compressor is a hydraulic compressor or a diaphragm compressor, When the required pressure of the supply destination is in a low-pressure region, the hydrogen gas compressed by the low-pressure compressor is supplied to the supply destination; A method for supplying hydrogen gas, characterized in that, when the required pressure of the supply destination is in the high-pressure region, hydrogen gas is compressed by the low-pressure compressor, the compressed hydrogen gas is introduced into the high-pressure compressor, and the hydrogen gas compressed by the high-pressure compressor is supplied to the supply destination.

2. 2. The method for supplying hydrogen gas according to claim 1, wherein the destination of the supply of the hydrogen gas is a pressure accumulator at a hydrogen station or a hydrogen storage tank of a mobile body.

3. 4. The method for supplying hydrogen gas according to claim 3, wherein the method for filling the hydrogen storage tank is a direct filling method from the compressor or a differential pressure filling method from the accumulator, or both the direct filling method and the differential pressure filling method.

4. 2. The method for supplying hydrogen gas according to claim 1, wherein the low-pressure region of the required pressure at the supply destination is a region where the upper limit value is any value between 40 and 50 MPa, and the high-pressure region is a region where the upper limit value is greater than any value of the low-pressure region and is equal to or less than 100 MPa.

5. 2. The method for supplying hydrogen gas according to claim 1, wherein the piston crank compressor and the hydraulic compressor or the diaphragm compressor share a common electric motor.

6. 7. The method for supplying hydrogen gas according to claim 6, further comprising providing a clutch for controlling ON / OFF of the drive of the hydraulic compressor or the diaphragm compressor.

7. A hydrogen gas supply method as described in claim 1, characterized in that the piston crank type compressor and the hydraulic compressor or diaphragm type compressor are mounted together, and common auxiliary equipment is shared to form a unit of a size that can fit on the same skid.

8. The hydrogen gas flow rate that can be supplied to the destination is 400 Nm ３ / Hr~1200Nm ３ 2. The method for supplying hydrogen gas according to claim 1, wherein the hydrogen gas supply rate is 1 / Hr.

9. It is equipped with a low-pressure compressor and a high-pressure compressor to compress hydrogen gas. A hydrogen gas supply system in which the required pressure of a supply destination has a low-pressure region and a high-pressure region, and hydrogen gas is supplied to the supply destination in accordance with the required pressure, the low-pressure compressor is a piston crank compressor, the high-pressure compressor is a hydraulic compressor or a diaphragm compressor, When the required pressure of the supply destination is in the low-pressure region, the hydrogen gas compressed by the low-pressure compressor is supplied to the supply destination; A hydrogen gas supply system characterized in that, when the required pressure at the supply destination is in the high-pressure region, hydrogen gas is compressed by the low-pressure compressor, the compressed hydrogen gas is introduced into the high-pressure compressor, and the hydrogen gas compressed by the high-pressure compressor is supplied to the supply destination.

10. 10. The hydrogen gas supply system according to claim 9, wherein the hydrogen gas is supplied to a pressure accumulator at a hydrogen station or a hydrogen storage tank of a mobile vehicle.

11. 11. The hydrogen gas supply system according to claim 10, wherein the method of filling the hydrogen storage tank is a direct filling method from the compressor, a differential pressure filling method via the accumulator, or a combination of the direct filling method and the differential pressure filling method.

12. The hydrogen gas supply system of claim 9, wherein the low-pressure region of the required pressure at the supply destination is a region where the upper limit value is any value between 40 and 50 MPa, and the high-pressure region is a region where the upper limit value of the low-pressure region is any value greater than 100 MPa or less.

13. 10. The hydrogen gas supply system according to claim 9, wherein the piston crank compressor and the hydraulic compressor or the diaphragm compressor share a common electric motor.

14. 14. The hydrogen gas supply system according to claim 13, further comprising a clutch for controlling ON / OFF of the drive of the hydraulic compressor or the diaphragm compressor.

15. The hydrogen gas supply system according to claim 9, characterized in that the piston crank compressor and the hydraulic compressor or diaphragm compressor are mounted together and common auxiliary equipment is shared, forming a compressor unit of a size that can fit on the same skid.

16. The hydrogen gas flow rate that can be supplied to the destination is 400 Nm ３ / Hr~1200Nm ３ 10. The hydrogen gas supply system according to claim 9, wherein the hydrogen gas supply rate is 1 / Hr.

17. a motor pulley (102) provided on a drive shaft (101) of the electric motor (100); a piston crank compressor pulley (103) provided on a piston crank compressor side drive shaft (107) of the piston crank compressor (1); a hydraulic compressor pulley (105) provided on a hydraulic compressor-side drive shaft (108) of the hydraulic compressor (2), The electric motor pulley (102) and the piston crank compressor pulley (103) are rotatably connected via a piston crank compressor belt (104), The electric motor pulley (102) and the hydraulic compressor pulley (105) are rotatably connected via a hydraulic compressor belt (106), The piston crank compressor (1) has a structure in which rotation of a drive shaft by driving an electric motor is converted into linear reciprocating motion of a piston via a crankshaft, thereby compressing hydrogen gas filled above the piston in a cylinder, and The hydraulic compressor (2) is configured such that the rotation of the drive shaft by the drive of an electric motor converts the hydraulic pressure generated by driving a hydraulic pump into reciprocating piston motion, and the reciprocating piston motion compresses the hydrogen gas filled in the cylinder.

18. a piping system (110) that leads to the suction side of the hydraulic compressor (2) that compresses high-pressure hydrogen via the low-pressure compression of the piston crank compressor (1) and then to the hydraulic compressor (2); and a branch piping system (111) that leads to the discharge side of the hydraulic compressor (2) by bypassing the hydraulic compressor (2) via the piston crank compressor (1) without entering the suction side of the hydraulic compressor (2), A control valve (112) for controlling opening and closing is provided in the branch piping system (111), a clutch (109) for disconnecting the driving force of the electric motor (105) of the hydraulic compressor (2) from the drive shaft (108) of the hydraulic compressor (2); When the required pressure of the hydrogen storage tank is below a set value, the clutch (109) is disengaged and the control valve (112) is opened; 11. The hydrogen gas supply system according to claim 10, wherein when the required pressure of the hydrogen storage tank exceeds the set value, the clutch (109) is engaged and the control valve (112) is closed.

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