Reciprocating compressor unit and method for operating compressor unit

Abstract

The compressor unit comprises: a connecting rod sealing part for sealing between the piston connecting rod and the cylinder part; and a leakage gas discharge part for discharging the hydrogen gas leaked to the connecting rod sealing part to the outside. The connecting rod sealing part comprises a sealing ring part; a discharge passage through which the hydrogen gas leaked through the seal ring part flows into the leaked gas discharge part; a gas seal part that forms a gas seal in a gap between the piston rod and the rod seal part on the basis of the hydrogen gas at a position located on the crank mechanism side with respect to the discharge passage; and a seal ring portion disposed between the gas seal portion and the discharge passage. And the pressure of the hydrogen in the gas sealing part is higher than that of the hydrogen in the leaked gas discharging part.

Description

Technical Field

[0001] The present invention relates to a reciprocating compressor unit and an operating method thereof. Background Art

[0002] In recent years, in consideration of the environment, research has been underway to use hydrogen as a fuel for power generation, automobiles, etc., and the demand for hydrogen is increasing. In addition, a compressor is used to recover low-temperature boil-off gases (BOGs) such as liquefied natural gas (LNG) and liquefied hydrogen (LH2) and supply them to demand sides such as engines. In particular, the boil-off gas generated by LH2 is extremely low in temperature. Therefore, if the compressor directly sucks in the boil-off gas, there will be limitations such as: the need to select materials suitable for extremely low temperatures; adopting design conditions considering the amount of thermal deformation; or, the need to implement strict heat insulation treatment.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open Publication No. 2020-172870

[0006] Patent Document 2: Japanese Patent Laid-Open Publication No. Hei 7-119634

[0007] In Patent Document 1, the following problems are pointed out. "In recent years, hydrogen has attracted attention as a new energy source. It is envisaged that when hydrogen is used as an energy source, it will also be stored and transported in a liquefied state like natural gas. However, hydrogen has the characteristic that its liquefaction temperature is lower than that of air. Therefore, if equipment such as a reciprocating mobile compressor for natural gas is directly applied to hydrogen, there may be adverse conditions caused by extremely low-temperature liquefied hydrogen. For example, it may cause liquefied air to be generated around the device supplying liquefied hydrogen."

[0008] Therefore, in Patent Document 1, various structures are proposed for the reciprocating mobile compressor. For example, the reciprocating mobile compressor includes an intermediate cylinder portion disposed between a piston drive portion and a container portion and accommodating a piston connecting rod. In the intermediate cylinder portion, a first intermediate chamber, a second intermediate chamber, and a connecting rod seal chamber are sequentially formed from the piston drive portion side. The internal pressure of the first intermediate chamber is higher than the internal pressures of the second intermediate chamber and the connecting rod seal chamber. Normal-temperature hydrogen is filled in the connecting rod seal chamber. Nitrogen is filled in the first intermediate chamber. A bleed port is provided at a position corresponding to the second intermediate chamber.

[0009] In Patent Document 1, it is disclosed that such a structure can suppress the leakage of hydrogen from the compression portion to the piston drive portion and enable the piston drive portion to operate reliably by suppressing the leakage of extremely low-temperature gas.

[0010] However, even if the internal pressure of the first intermediate chamber is set higher than the internal pressures of the second intermediate chamber and the connecting rod seal chamber, nitrogen gas in the first intermediate chamber may flow into the connecting rod seal chamber. Moreover, when nitrogen gas comes into contact with extremely low-temperature hydrogen gas (the suction gas of the compressor), the nitrogen gas may liquefy.

[0011] In addition, in the reciprocating compressor disclosed in Patent Document 2, the following structure is disclosed. "The compressed gas branched from the discharge passage 7 is cooled by the gas cooler 23 and is guided to the cooling chamber 22 through the discharge passage side portion 28a of the cooling passage 28 in the seal housing 10, thereby directly cooling the piston rod 1. Thereafter, the compressed gas returns to the suction passage 5 through the suction passage side portion 28b of the cooling passage 28 in the seal housing 10."

[0012] In Patent Document 2, since the purpose is to cool the piston rod 1, the compressed gas flows through the cooling chamber 22 without hindrance. Such a structure may not be necessarily appropriate for the purpose of preventing nitrogen gas from coming into contact with extremely low-temperature hydrogen gas (the suction gas of the compressor). Summary of the Invention

[0013] An object of the present invention is to realize a sealing structure suitable for a reciprocating compressor unit that uses the evaporation gas of liquefied hydrogen.

[0014] The present invention relates to a compressor unit, which is a reciprocating compressor unit that recovers evaporated gas, i.e., hydrogen, from a liquefied hydrogen storage tank via an intake passage and supplies at least a part of the hydrogen to a demand side including at least one of an engine, a power generation device, and a boiler. The reciprocating compressor unit includes: a compression section that compresses the hydrogen in the intake passage; and a crank mechanism that drives the compression section. The compression section includes: a cylinder portion; a piston; a piston connecting rod that connects the piston to the crank mechanism; a connecting rod seal portion that seals between the piston connecting rod and the cylinder portion; an adapter portion that connects the cylinder portion to a housing of the crank mechanism; a nitrogen supply portion that supplies nitrogen to the inside of the adapter portion; a leaked gas discharge portion that discharges hydrogen leaked to the connecting rod seal portion to the outside; and a hydrogen supply portion that supplies hydrogen to the connecting rod seal portion. The connecting rod seal portion includes: at least one seal ring portion that contacts the piston connecting rod and seals between the piston connecting rod and the cylinder portion; a discharge passage that is connected to the leaked gas discharge portion and allows a part of the gas compressed in the cylinder portion, which is hydrogen leaked via the seal ring portion, to flow into the leaked gas discharge portion; a gas seal portion that forms a gas seal in a gap between the piston connecting rod and the connecting rod seal portion based on hydrogen supplied from the hydrogen supply portion at a position on the side of the crank mechanism relative to the discharge passage; and at least one other seal ring portion that is disposed between the gas seal portion and the discharge passage. The pressure of the hydrogen in the gas seal portion is higher than the pressure of the hydrogen in the leaked gas discharge portion.

[0015] The present invention relates to a compressor unit, which is a reciprocating compressor unit that recovers evaporated gas, i.e., hydrogen, from a liquefied hydrogen storage tank via an intake passage and supplies at least a part of the hydrogen to a demand side including at least one of an engine, a power generation device, and a boiler. The reciprocating compressor unit includes: a compression section that compresses the hydrogen in the intake passage; and a crank mechanism that drives the compression section. The compression section includes: a cylinder part; a piston; a piston connecting rod that connects the piston to the crank mechanism; a connecting rod seal part that seals between the piston connecting rod and the cylinder part; an adapter part that connects the cylinder part to the housing of the crank mechanism; a nitrogen supply part that supplies nitrogen to the inside of the adapter part; a hydrogen supply part that supplies hydrogen to other parts inside the adapter part; and a leaked gas discharge part that discharges the hydrogen leaked to the connecting rod seal part to the outside. The connecting rod seal part includes: at least one seal ring part that contacts the piston connecting rod and seals between the piston connecting rod and the cylinder part; a discharge passage that connects to the leaked gas discharge part and allows a part of the gas compressed in the cylinder part, which is the hydrogen leaked via the seal ring part, to flow into the leaked gas discharge part; and at least one other seal ring part that is arranged on the side of the crank mechanism with respect to the discharge passage. The adapter part includes a partition part that divides the inside of the adapter part into a plurality of spaces. The hydrogen supply part is configured to supply hydrogen to the space closest to the compression chamber inside the adapter part. The nitrogen supply part is configured to supply nitrogen to at least one space on the side of the crank mechanism with respect to the space closest to the compression chamber inside the adapter part. The pressure of the hydrogen in the space closest to the compression chamber is higher than the pressure of the hydrogen in the leaked gas discharge part.

[0016] The present invention relates to an operation method of the compressor unit, in which nitrogen is supplied to the inside of the adapter part by the nitrogen supply part not only during the operation of the compression section but also during the stop of the compression section. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FIG. is a diagram schematically showing the overall configuration of the compressor unit according to the first embodiment.

[0018] Figure 2 FIG. is a diagram schematically showing the compression section provided in the compressor unit.

[0019] Figure 3 FIG. is a diagram showing the configuration of the connecting rod seal part provided in the compression section.

[0020] Figure 4 FIG. is a diagram for explaining the operation of the compressor unit.

[0021] Figure 5This is a diagram schematically showing the overall configuration of a compressor unit according to a modified example of the first embodiment.

[0022] Figure 6 This is a diagram schematically showing the overall configuration of a compressor unit according to the second embodiment.

[0023] Figure 7 This is a diagram schematically showing the overall configuration of a compressor unit according to the third embodiment.

[0024] Figure 8 This is a diagram schematically showing the overall configuration of a compressor unit according to a modified example of the third embodiment.

[0025] Figure 9 This is a diagram schematically showing the overall configuration of a compressor unit according to a modified example of the third embodiment.

[0026] Figure 10 This is a diagram schematically showing the overall configuration of a compressor unit according to a modified example of the third embodiment. Detailed Embodiment

[0027] Hereinafter, embodiments for implementing the present invention will be described in detail with reference to the drawings.

[0028] (First Embodiment)

[0029] The compressor unit according to the present embodiment is configured to recover boil-off gas, that is, hydrogen, from a liquefied hydrogen storage tank and compress and supply the recovered hydrogen to a demand side. The boil-off gas, that is, hydrogen, is approximately -253°C. The demand side includes at least one of an engine, a power generation device, and a boiler. However, in the demand side, in addition to the above-mentioned ones, it may also include, for example, devices such as gas combustion equipment, flame equipment, and gas venting, that is, devices other than "devices that use gas as an energy source". In addition, the hydrogen discharged from the compressor unit does not necessarily have to be directly supplied to the demand side. It is also possible to supply hydrogen to the demand side by various means such as filling it into, for example, a gas cylinder and then transporting the gas cylinder or a gas pipe connected to the gas cylinder.

[0030] As Figure 1 shown, the compressor unit 10 includes: a compression section (first compression section) 12 for compressing hydrogen; and a crank mechanism 14 for driving the compression section 12. The compressor unit 10 further includes a second compression section 16 for further compressing the hydrogen compressed in the compression section 12. That is, a discharge flow path 18 is connected to the compression section 12, and the hydrogen compressed in the compression section 12 is discharged to the discharge flow path 18. The second compression section 16 is provided in the discharge flow path 18. The hydrogen compressed in the second compression section 16 is supplied to the demand side 20.

[0031] The compression section 12 is connected to the liquefied hydrogen storage tank 23 via the suction flow path 21. Therefore, the evaporated gas of the liquefied gas generated in the liquefied hydrogen storage tank 23 is sucked into the compression section 12 via the suction flow path 21.

[0032] The crank mechanism 14 drives the above-mentioned compression section 12 and the second compression section 16 together. However, the configuration is not limited to this. For example, the second compression section 16 may be omitted, and a configuration may be adopted in which the crank mechanism 14 drives only one compression section 12. In addition, one or more compression sections for further compressing the hydrogen compressed in the second compression section 16 may be provided for the compressor unit 10.

[0033] The compressor unit 10 includes: a reflux section (first reflux section) 25 for returning the hydrogen discharged from the compression section 12 to the suction flow path 21; and a second reflux section 27 for returning the hydrogen discharged from the second compression section 16 to the suction flow path 21.

[0034] The reflux section 25 has: a reflux flow path 25a; and a reflux valve 25b, which is disposed on the reflux flow path 25a and is constituted by a valve capable of adjusting the opening degree. One end portion of the reflux flow path 25a is connected to a portion of the discharge flow path 18 upstream of the second compression section 16, and the other end portion is connected to the suction flow path 21. The pressure and flow rate of the hydrogen sucked into the second compression section 16 are adjusted by controlling the opening degree of the reflux valve 25b. In addition, the reflux section 25 may be omitted.

[0035] The second reflux section 27 has: a second reflux flow path 27a; and a second reflux valve 27b, which is disposed on the second reflux flow path 27a and is constituted by a valve capable of adjusting the opening degree. One end portion of the second reflux flow path 27a is connected to a portion of the discharge flow path 18 downstream of the second compression section 16, and the other end portion is connected to the suction flow path 21. The pressure and flow rate of the hydrogen supplied to the demand side 20 are adjusted by controlling the opening degree of the second reflux valve 27b. In addition, if the main purpose is to equalize the pressure between the suction flow path 21 and the discharge flow path 18 when the compressor unit 10 is in a stopped state, a manual valve or an on-off valve may be used as the second reflux valve 27b.

[0036] As Figure 2 shown, the compression section 12 is composed of a reciprocating compression mechanism. That is, the compression section 12 includes: a cylinder portion 31; a piston 32 disposed in the cylinder portion 31; and a piston connecting rod 33 connected to the piston 32. The piston connecting rod 33 is connected to the crank mechanism 14. The hydrogen is compressed in the compression chamber 34 by the reciprocating movement of the piston 32 in the cylinder portion 31.

[0037] Furthermore, Figure 2The compression section 12 of the double-acting structure is shown, but the compression section 12 can also adopt a single-acting structure. In addition, the compression section 12 does not necessarily have to be composed of 1 cylinder or 1 compression section, and it can also be composed of multiple compression sections arranged in parallel. That is, the compression section 12 can also be set to a structure in which hydrogen is compressed by pistons 32 respectively in a plurality of cylinder parts 31 connected in parallel to increase the pressure.

[0038] The compression section 12 includes: a connecting rod seal part 36 provided in the cylinder part 31; an adapter part 37 configured to be adjacent to and connected to the cylinder part 31; and a crankcase 38 which is a housing for accommodating a crankshaft that is a part of the crank mechanism 14. The crankcase 38 is a component constituting the crank mechanism 14.

[0039] The adapter part 37 is formed in a cylindrical shape. The piston connecting rod 33 is disposed in the space inside the adapter part 37. One end in the longitudinal direction of the adapter part 37 is connected to the cylinder part 31. The other end in the longitudinal direction of the adapter part 37 is connected to the crankcase 38. A partition wall 40 for separating the internal space of the adapter part 37 from the space inside the crankcase 38 is provided at the other end.

[0040] The connecting rod seal part 36 is fixed to the rear cover 31a which is a part of the cylinder part 31. The connecting rod seal part 36 is provided to prevent hydrogen in the compression chamber 34 of the cylinder part 31 from leaking out from inside the cylinder part 31 through the gap between the rear cover 31a and the piston connecting rod 33. That is, the connecting rod seal part 36 seals between the piston connecting rod 33 and the cylinder part 31. A through hole (not shown) for the piston connecting rod 33 to pass through is provided in the rear cover 31a, and the connecting rod seal part 36 is disposed in the through hole.

[0041] As Figure 3 shown, the connecting rod seal part 36 has: at least 1 seal ring part (the first seal ring part 41); a housing part (the first housing part 42) for accommodating the first seal ring part 41; at least 1 other seal ring part (the second seal ring part 43); another housing part (the second housing part 44) for accommodating the second seal ring part 43; at least 1 further other seal ring part (the third seal ring part 45); and a further other housing part (the third housing part 46) for accommodating the third seal ring part 45. The second seal ring part 43 and the second housing part 44 are disposed on the side opposite to the first seal ring part 41 and the first housing part 42 with respect to the compression chamber 34 (the side of the crank mechanism 14). The third seal ring part 45 and the third housing part 46 are disposed on the side opposite to the second seal ring part 43 and the second housing part 44 with respect to the compression chamber 34 (the side of the crank mechanism 14).

[0042] In addition, in Figure 3In the structure shown, a plurality of first seal ring portions 41 are provided in each of the plurality of first housing portions 42, a plurality of second seal ring portions 43 are provided in one second housing portion 44, and a plurality of third seal ring portions 45 are provided in one third housing portion 46. However, the structure is not limited thereto. For example, a structure in which one seal ring portion 41, 43, 45 is provided in each of the housing portions 42, 44, 46 may also be employed. However, by arranging a plurality of seal ring portions 41, 43, 45 in each of the housing portions 42, 44, 46, the sealing performance can be further improved, and it is better suited for the high-pressure compression section 12.

[0043] The first housing portion 42, the second housing portion 44, and the third housing portion 46 are arranged in the extending direction of the piston connecting rod 33 and are disposed within the through hole of the rear cover 31a. The first housing portion 42, the second housing portion 44, and the third housing portion 46 are mounted to the rear cover 31a from the side of the crank mechanism 14 based on the flange portion 47 in this state.

[0044] A through hole through which the piston connecting rod 33 passes is formed in each of the first housing portion 42, the second housing portion 44, and the third housing portion 46. A gap 50 is formed between the inner peripheral portion that divides the through hole in the first housing portion 42, the second housing portion 44, and the third housing portion 46 and the outer peripheral surface of the piston connecting rod 33, respectively.

[0045] The seal ring portions 41, 43, 45 are arranged in the extending direction of the piston connecting rod 33 and are configured to surround the piston connecting rod 33. The seal ring portions 41, 43, 45 are deformed to be in close contact with the outer peripheral surface of the piston connecting rod 33 based on high-pressure hydrogen. In addition, the seal ring portions 41, 43, 45 may be formed to be of a size that is in close contact with the outer peripheral surface of the piston connecting rod 33 even in a state where they are not subjected to the pressure of high-pressure hydrogen, or may be configured to be in close contact with the outer peripheral surface by being pressed by a spring.

[0046] A discharge passage 52 is provided in the connecting rod seal portion 36 so as to pass between the first seal ring portion 41 and the second seal ring portion 43. The discharge passage 52 is a passage for allowing hydrogen that has leaked to the side of the second seal ring portion 43 through the first seal ring portion 41 to flow into a leak gas discharge portion 66 described later. The discharge passage 52 opens to the gap 50 between the second housing portion 44 and the outer peripheral surface of the piston connecting rod 33. The discharge passage 52 is connected to the leak gas discharge portion 66 described later and allows hydrogen that has leaked into the gap 50 between the second housing portion 44 and the outer peripheral surface of the piston connecting rod 33 to flow into the leak gas discharge portion 66 described later.

[0047] In addition, a gas seal portion 54 is provided in the connecting rod seal portion 36. The gas seal portion 54 is based on the first hydrogen supply portion 58 described later (refer to Figure 2) The hydrogen gas forms a gas seal 54a in the gap 50 between the outer peripheral surface of the piston connecting rod 33 and the third housing portion 46 (connecting rod seal portion 36). The gas seal portion 54 has an introduction passage 54b of a hydrogen flow passage 58a that is formed in the third housing portion 46 and is connected to a first hydrogen supply portion 58 described later. The third seal ring portion 45 is located on the side opposite to the second seal ring portion 43 and the first seal ring portion 41 with respect to the gas seal 54a. Further, the gas seal 54a is located on the adapter portion 37 side (first space 37a side) with respect to the discharge passage 52.

[0048] As Figure 2 shown, the adapter portion 37 includes: a partition portion 56 that divides the internal space into a space on the compression chamber 34 side (first space 37a) and a space on the crank mechanism 14 side (second space 37b). In Figure 2 the form shown, the partition portion 56 is constituted by a single partition member 56b. The piston connecting rod 33 also passes through the partition portion 56. A seal portion 56a is provided at the peripheral edge of the through-hole in the partition member 56b (partition portion 56) through which the piston connecting rod 33 passes.

[0049] The compression section 12 includes: a hydrogen supply portion (first hydrogen supply portion 58) that supplies hydrogen to the connecting rod seal portion 36; another hydrogen supply portion (second hydrogen supply portion 59) that supplies hydrogen to the first space 37a within the adapter portion 37; and a nitrogen supply portion 60 that supplies nitrogen to the second space 37b within the adapter portion 37.

[0050] The first hydrogen supply portion 58 has: a hydrogen flow passage 58a that is connected to a hydrogen source 61. The first hydrogen supply portion 58 is configured to supply hydrogen from the hydrogen source 61 to the gas seal portion 54 in the connecting rod seal portion 36 via the hydrogen flow passage 58a. The first hydrogen supply portion 58 supplies hydrogen to the gap 50 where seal ring portions exist on both sides (that is, the gap 50 between the first seal ring portion 41 and the second seal ring portion 43). The hydrogen source 61 houses hydrogen at normal temperature.

[0051] The second hydrogen supply portion 59 has: a second hydrogen flow passage 59a that is connected to the hydrogen flow passage 58a. The second hydrogen flow passage 59a is connected to a supply port formed on the outer peripheral wall that forms the first space 37a in the adapter portion 37. The second hydrogen supply portion 59 supplies hydrogen from the hydrogen source 61 to the first space 37a within the adapter portion 37 via the second hydrogen flow passage 59a. Therefore, it can be said that the temperature of the hydrogen in the first space 37a is higher than the liquefaction temperature of the nitrogen in the second space 37b.

[0052] The nitrogen supply unit 60 has a nitrogen flow path 60a connected to a nitrogen source 62. The nitrogen flow path 60a is connected to a supply port formed on the outer peripheral wall of the second space 37b formed in the adapter portion 37. The nitrogen supply unit 60 supplies nitrogen from the nitrogen source 62 to the second space 37b in the adapter portion 37 via the nitrogen flow path 60a. The nitrogen source 62 contains nitrogen at room temperature.

[0053] A valve for adjusting the pressure of hydrogen flowing in the hydrogen flow path 58a, that is, a first hydrogen valve 58b, is provided in the hydrogen flow path 58a. A valve for adjusting the pressure of hydrogen flowing in the second hydrogen flow path 59a of the second hydrogen supply unit 59, that is, a second hydrogen valve 59b, is provided in the second hydrogen flow path 59a. A valve for adjusting the pressure of nitrogen flowing in the nitrogen flow path 60a, that is, a nitrogen valve 60b, is provided in the nitrogen flow path 60a.

[0054] The first hydrogen valve 58b, the second hydrogen valve 59b, and the nitrogen valve 60b constitute a pressure adjustment unit 63 that adjusts at least one of the pressure of hydrogen supplied by the first hydrogen supply unit 58, the pressure of hydrogen supplied by the second hydrogen supply unit 59, and the pressure of nitrogen supplied by the nitrogen supply unit 60. For example, when the pressure of hydrogen in the gas seal portion 54 is set as pressure P1, the pressure of hydrogen in the first space 37a in the adapter portion 37 is set as pressure P2, and the pressure of nitrogen in the second space 37b in the adapter portion 37 is set as pressure P3, at least one of the first hydrogen valve 58b, the second hydrogen valve 59b, and the nitrogen valve 60b is adjusted so that the relationship pressure P1 > pressure P2 > pressure P3 holds. That is, since the pressure in the first space 37a into which hydrogen at room temperature is introduced is higher than the pressure in the second space 37b into which nitrogen is introduced, nitrogen in the second space 37b is prevented from invading the first space 37a. In addition, since the pressure in the gas seal portion 54 is higher than the pressure in the first space 37a, even if nitrogen invades the first space 37a, the nitrogen can be prevented from invading the link seal portion 36.

[0055] The compression section 12 includes a leakage gas discharge portion 66 that discharges leakage gas (hydrogen) from the link seal portion 36, a first discharge portion 67 that discharges hydrogen in the first space 37a, and a second discharge portion 68 that discharges nitrogen in the second space 37b.

[0056] The leakage gas discharge portion 66 has a pipe member connected to the link seal portion 36 so as to communicate with the discharge passage 52 provided in the link seal portion 36 ( Figure 3) Communicate. The leaked gas discharge part 66 is connected to the suction passage 21 for allowing hydrogen to flow into the compression chamber 34 of the compression section 12. Based on the discharge passage 52 communicating with the leaked gas discharge part 66, it is possible to return the hydrogen that leaks from the compression chamber 34 and passes through the first seal ring part 41 to the suction passage 21 via the discharge passage 52 and the leaked gas discharge part 66. A check valve 69 for preventing hydrogen from flowing toward the connecting rod seal part 36 is provided in the leaked gas discharge part 66. In addition, the leaked gas discharge part 66 may be connected to the bleed port 70 instead of being connected to the suction passage 21 of the compression section 12. In addition, in the second compression section 16, a leaked gas discharge part (second leaked gas discharge part) may be provided in the same manner as the compression section 12 so as to communicate with the discharge passage provided in the connecting rod seal part. The second leaked gas discharge part is connected to the suction passage 21.

[0057] The first discharge part 67 is connected to the adapter part 37 so as to open to the first space 37a. That is, one end of the first discharge part 67 is connected to the discharge port formed on the outer peripheral wall forming the first space 37a in the adapter part 37. In addition, the other end of the first discharge part 67 is connected to the suction passage 21 of the compression section 12. Therefore, the hydrogen in the first space 37a can return to the compression chamber 34 via the first discharge part 67 and the suction passage 21. In addition, the first discharge part 67 may be connected to the bleed port 70 instead of being connected to the suction passage 21 of the compression section 12.

[0058] The second discharge part 68 is connected to the adapter part 37 so as to open to the second space 37b. That is, one end of the second discharge part 68 is connected to the discharge port formed on the outer peripheral wall forming the second space 37b in the adapter part 37. In addition, the other end of the second discharge part 68 is connected to the bleed port 70. In addition, the second discharge part 68 can also serve the function of recovering the liquid generated in the second space 37b. In this case, a drain pot or the like may also be provided in the second discharge part 68.

[0059] An opening and closing valve 68a is provided in the second discharge part 68. The opening and closing valve 68a constitutes a release-side pressure adjustment unit that releases nitrogen when the pressure at the nitrogen discharge port in the adapter part 37 becomes a specified pressure or higher. Therefore, when the pressure in the second space 37b in the adapter part 37 becomes a specified pressure or higher, based on the opening of the opening and closing valve 68a, the nitrogen in the second space 37b is released to the bleed port 70. That is, the opening and closing valve 68a can be constituted by an overflow valve.

[0060] Here, the operation when the compressor unit 10 is stopped is described. As Figure 4As shown, in the compressor unit 10, if the crank mechanism 14 operates, the piston 32 will operate. Thus, the evaporation gas, i.e., hydrogen, is inhaled from the suction flow path 21 into the compression chamber 34, and hydrogen compression is performed (step ST11).

[0061] During the period when the crank mechanism 14 is driven, the first hydrogen valve 58b, the second hydrogen valve 59b, and the nitrogen valve 60b are opened. Therefore, hydrogen is supplied to the gas seal portion 54 based on the first hydrogen supply portion 58. In addition, hydrogen is supplied to the first space 37a in the adapter portion 37 based on the second hydrogen supply portion 59. In addition, nitrogen is supplied to the first space 37a in the adapter portion 37 based on the nitrogen supply portion 60 (step ST12). At this time, the relationship of pressure P1 (the pressure of hydrogen in the gas seal portion 54) > pressure P2 (the pressure of hydrogen in the first space 37a in the adapter portion 37) > pressure P3 (the pressure of nitrogen in the second space 37b in the adapter portion 37) holds. Therefore, intrusion of nitrogen from the second space 37b into the first space 37a is prevented. In addition, even if nitrogen intrudes into the first space 37a, it is possible to prevent nitrogen from intruding into the connecting rod seal portion 36.

[0062] If an instruction to stop the compressor unit 10 is received, the compressor unit 10 stops operating (step ST13). At this time, the supply of nitrogen by the nitrogen supply portion 60 continues. That is, the supply of nitrogen to the inside of the adapter portion 37 is performed not only during the operation of the compression section 12 but also during the stop of the compression section 12. That is, since the discharge pipe (not shown) connected to the discharge port of the space on the crank mechanism 14 side of the adapter portion 37 is mostly open to the atmosphere, when the supply of nitrogen is stopped, the atmosphere may intrude into the space on the crank mechanism 14 side of the adapter portion 37. Therefore, in order to prevent the atmosphere from intruding into the second space 37b during the stop of the compression section 12, the supply of nitrogen continues.

[0063] During the stop of the compression section 12, it is determined whether to stop the supply of nitrogen based on the nitrogen supply portion 60 (step ST14). That is, the supply of nitrogen continues during the period when the compression section 12 is at a low temperature. On the other hand, when it returns to normal temperature, since there is no problem of dew condensation, it is determined whether the temperature of a specified place in the compression section 12 (the temperature detected by a temperature detector (not shown)) has returned to a preset specified temperature (for example, a temperature at which dew condensation is not generated in the piston connecting rod 33). And if the determination in step ST14 is "yes", the supply of nitrogen by the nitrogen supply portion 60 is stopped (step ST15). In addition, during the supply of nitrogen, the supply of hydrogen can be continued or stopped. In addition, the supply of nitrogen during the stop of the compressor unit 10 can be performed all the time, but even in such a case, it can be stopped during maintenance or the like.

[0064] As described above, in the present embodiment, a discharge passage 52 is provided in the connecting rod seal portion 36, and the discharge passage 52 is connected to the leakage gas discharge portion 66. Therefore, the hydrogen gas leaked through the first seal ring portion 41 is discharged to the outside of the connecting rod seal portion 36 and the adapter portion 37 via the discharge passage 52 and the leakage gas discharge portion 66. Further, in the connecting rod seal portion 36, a hydrogen-based gas seal portion 54 is provided on the side of the crankcase 38 with respect to the discharge passage 52, and the pressure of the hydrogen gas in the gas seal portion 54 becomes higher than the pressure in the leakage gas discharge portion 66. Thereby, it is possible to prevent the evaporated gas (inhaled gas) of the cryogenic gas, i.e., liquefied hydrogen, compressed in the cylinder portion 31 from invading the adapter portion 37 side and the crankcase 38 side across the gas seal portion 54, and thereby, it is possible to prevent nitrogen liquefaction.

[0065] Further, hydrogen gas is used in the gas seal 54a of the connecting rod seal portion 36. Therefore, even when the sealing gas leaks into the cylinder portion 31, it is possible to prevent an unexpected situation such as liquefaction caused by cooling by the inhaled gas (hydrogen gas) as compared with the case where a different type of gas is used as the sealing gas.

[0066] Further, in the present embodiment, the pressure of the hydrogen gas in the gas seal portion 54 provided in the connecting rod seal portion 36 is higher than the pressure of the nitrogen gas in the adapter portion 37. Therefore, it is possible to prevent the nitrogen gas supplied to the adapter portion 37 from crossing the gas seal portion 54 provided in the connecting rod seal portion 36. Therefore, it is possible to more reliably prevent the leaked gas of the evaporated gas (inhaled gas) of the cryogenic gas, i.e., liquefied hydrogen, compressed in the cylinder portion 31 from coming into direct contact with the nitrogen gas.

[0067] Further, in the present embodiment, the space in the adapter portion 37 is partitioned into a first space 37a and a second space 37b by the spacer member 56b (spacer portion 56), and the temperature of the hydrogen gas in the first space 37a supplied by the second hydrogen supply portion 59 is higher than the liquefaction temperature of the nitrogen gas in the second space 37b. Therefore, it is possible to prevent nitrogen liquefaction.

[0068] Further, in the present embodiment, at least one of the first hydrogen valve 58b, the second hydrogen valve 59b, and the nitrogen valve 60b is adjusted so that the relationship of pressure P1 > pressure P2 > pressure P3 is established. Therefore, since the nitrogen gas does not flow from the second space 37b into the first space 37a, the nitrogen gas does not flow into the connecting rod seal portion 36. Therefore, it is possible to prevent nitrogen liquefaction.

[0069] Further, as long as the pressure in the second space 37b is not too high, the on-off valve 68a of the second discharge portion 68 is closed, and the nitrogen gas is held in the second space 37b of the adapter portion 37. Thereby, it is possible to reduce the consumption amount of the nitrogen gas as compared with the case where purification is always performed.

[0070] The components of the compression section 12, namely the cylinder part 31, the piston 32, and the piston connecting rod 33, become low-temperature during operation. Even when the compressor unit 10 stops, they do not immediately return to normal temperature, and the state of being at low temperature continues for a long time. On the other hand, when the supply of nitrogen is stopped, the atmosphere may invade the second space 37b of the adapter part 37. Therefore, when the piston connecting rod 33 is in a low-temperature state, if the atmosphere invades the second space 37b, condensation may occur on the piston connecting rod 33. In this case, rusting of the internal components and / or condensation adhering to the surface of the piston connecting rod 33 may cause damage to the sealing functions of the seal ring parts 41, 43, and 45. However, since nitrogen is supplied not only during the operation of the compression section 12 but also during the stop, rusting of the internal components and deterioration of the sealing function can be prevented.

[0071] In addition, in the present embodiment, the inside of the adapter part 37 is separated into a first space 37a and a second space 37b by the spacer member 56b (spacer part 56), and a second hydrogen supply part 59 for supplying hydrogen to the first space 37a is provided. However, it is not limited thereto. For example, as Figure 5 shown, the spacer part 56 and the second hydrogen supply part 59 may be omitted, and nitrogen may be supplied into the space inside the adapter part 37 by the nitrogen supply part 60.

[0072] In addition, in the above-described embodiment, the pressure of the hydrogen in the gas seal part 54 is adjusted to be higher than the pressure of the nitrogen in the adapter part 37. However, it is not limited thereto. For example, as long as the pressure P2 of the hydrogen in the first space 37a is higher than the pressure P3 of the nitrogen in the second space 37b, the pressure P1 of the hydrogen in the gas seal part 54 may be the same as or lower than the pressure P3 of the nitrogen in the adapter part 37.

[0073] In addition, in the above-described embodiment, at least one of the first hydrogen valve 58b, the second hydrogen valve 59b, and the nitrogen valve 60b is adjusted so that the relationship of pressure P1 > pressure P2 > pressure P3 holds. However, it is not limited thereto. For example, at least one of the first hydrogen valve 58b, the second hydrogen valve 59b, and the nitrogen valve 60b may be adjusted so that the relationship of pressure P1 > pressure P3 > pressure P2 holds. That is, the first hydrogen valve 58b, the second hydrogen valve 59b, and the nitrogen valve 60b may also constitute a supply-side pressure adjustment unit that adjusts the pressure of at least one of the first hydrogen supply part 58, the second hydrogen supply part 59, and the nitrogen supply part 60 so that the relationship of pressure P1 > pressure P3 > pressure P2 holds. In this case, leakage of the combustible gas hydrogen to the crankcase 38 side can be more actively prevented. That is, since the pressure P3 in the second space 37b is higher than the pressure P2 in the first space 37a, leakage of the hydrogen in the first space 37a to the crankcase 38 side can be prevented.

[0074] Even in this case, as long as the pressure P3 in the second space 37b is not too high, the on-off valve 68a of the second discharge section 68 remains closed. Therefore, nitrogen can be retained in the second space 37b of the adapter section 37, and thus, compared with the case where purification is always carried out, the consumption of nitrogen can be reduced.

[0075] In the present embodiment, there are provided: a first discharge section 67 that discharges hydrogen in the first space 37a; and a second discharge section 68 that discharges nitrogen in the second space 37b. However, the first discharge section 67 and the second discharge section 68 may be omitted. That is, the first space 37a may have a closed structure, that is, it may be configured such that hydrogen flowing into the first space 37a is not discharged to the outside, and thus the pressure in the first space 37a is maintained at a specified pressure. In addition, the second space 37b may have a closed structure, that is, it may be configured such that nitrogen in the second space 37b is not discharged to the outside, and thus the pressure in the second space 37b is maintained at a specified pressure. Even in this case, the pressure adjustment unit 63 is adjusted so as to maintain the above-described pressure relationship. This structure can also be applied to the second embodiment, the third embodiment, and their modified examples described later.

[0076] (Second Embodiment)

[0077] Figure 6 The second embodiment is shown. Here, the same reference numerals are given to the same components as those in the first embodiment, and the detailed description thereof is omitted.

[0078] In the second embodiment, there is provided: a transfer pipe 72 that connects the hydrogen flow path 58a of the first hydrogen supply section 58 and the discharge flow path 18 to each other. That is, in the first embodiment, the hydrogen flow path 58a is connected to the hydrogen source 61, while in the second embodiment, the hydrogen flow path 58a is connected to the discharge flow path 18 via the transfer pipe 72. Through the transfer pipe 72, a part of the hydrogen discharged from the compression section 12 to the discharge flow path 18 can be transferred to the gas seal section 54. In addition, a leaked gas discharge section 66 that recovers leaked gas from the link seal section 36 is connected to the suction flow path 21 of the compression section 12. However, the leaked gas discharge section 66 may also be connected to the bleed port 70.

[0079] Therefore, leaked hydrogen can be recovered. There is no need to separately prepare hydrogen for the gas seal 54a.

[0080] The description of other configurations, operations, and effects is omitted, but the description of the first embodiment can be cited for the second embodiment.

[0081] (Third Embodiment)

[0082] Figure 7Indicates the third embodiment. Here, the same reference numerals are given to the same components as in the first embodiment, and the detailed description thereof is omitted.

[0083] In the third embodiment, the first hydrogen supply section 58 that supplies hydrogen to the connecting rod seal section 36 is omitted, and the gas seal section 54 is omitted from the connecting rod seal section 36. That is, in the third embodiment, there are provided: a nitrogen supply section 60 that supplies nitrogen into the adapter section 37; a hydrogen supply section 74 that supplies hydrogen to other parts inside the adapter section 37; and a leaked gas discharge section 66 that discharges the hydrogen leaked into the connecting rod seal section 36 to the outside. The hydrogen supply section 74 supplies hydrogen to the space (first space 37a) closest to the compression chamber side inside the adapter section 37. The nitrogen supply section 60 supplies nitrogen to at least one space (second space 37b) on the crank mechanism side with respect to the first space 37a inside the adapter section 37. Further, in Figure 7 it shows an example in which the spacer section 56 is composed of one spacer member 56b, and thus one second space 37b is formed. Instead of this, the spacer section 56 may be composed of, for example, two spacer members 56b, thereby forming two second spaces 37b. In this case, nitrogen is supplied to the two second spaces 37b respectively.

[0084] A valve for adjusting the pressure of the hydrogen flowing in the hydrogen flow path 74a, that is, a hydrogen valve 74b, is provided in the hydrogen flow path 74a of the hydrogen supply section 74. The hydrogen valve 74b is adjusted so that the pressure of the hydrogen in the first space 37a is higher than the pressure of the hydrogen in the leaked gas discharge section 66. Thereby, even if the hydrogen in the compression chamber 34 leaks into the connecting rod seal section 36, it is possible to prevent the hydrogen from invading into the adapter section 37.

[0085] Therefore, in the third embodiment, the pressure of the hydrogen in the first space 37a inside the adapter section 37 supplied by the hydrogen supply section 74 is higher than the pressure of the hydrogen in the leaked gas discharge section 66. Therefore, it is possible to prevent the hydrogen leaked into the connecting rod seal section 36 from invading into the space (first space 37a) closest to the compression chamber side in the adapter section 37. Thereby, it is possible to prevent the evaporation gas of the cryogenic gas, that is, liquefied hydrogen, from directly contacting nitrogen, and it is possible to prevent nitrogen from liquefying.

[0086] Further, in the third embodiment, as Figure 8As shown, the compression section 12 may include: another hydrogen supply section 76 that supplies hydrogen to the connecting rod seal section 36. The another hydrogen supply section 76 has: another flow path 76a that is connected to the connecting rod seal section 36. The another flow path 76a may also be connected to the gas seal section 54 of the connecting rod seal section 36. Based on the hydrogen supplied via the another flow path 76a, a gas seal 54a is formed in the gap 50 between the outer peripheral surface of the piston connecting rod 33 and the third housing section 46 on the side of the crank mechanism 14 with respect to the discharge passage 52.

[0087] In the another flow path 76a, there is provided: another valve 76b formed of a valve capable of adjusting the opening degree. The another valve 76b is adjusted such that the pressure of the hydrogen in the gas seal section 54 is higher than the pressure of the hydrogen in the leakage gas discharge section 66. That is, the pressure of the gas seal 54a formed based on the gas seal section 54 is higher than the pressure in the discharge passage 52 on the compression chamber 34 side with respect to the gas seal 54a. Therefore, even if hydrogen leaks from the inside of the compression chamber 34 and may pass through the first seal ring section 41, it can be prevented from passing through the gas seal 54a.

[0088] In the third embodiment, as Figure 9 shown, a transfer pipeline 72 may be provided to connect the hydrogen flow path 74a of the hydrogen supply section 74 and the discharge flow path 18 to each other. Through the transfer pipeline 72, a part of the hydrogen discharged from the compression section 12 to the discharge flow path 18 can be transferred to the gas seal section 54.

[0089] As Figure 10 shown, the space in the adapter section 37 may be divided into three spaces by two spacer members 56b. That is, the spacer section 56 may be composed of two spacer members 56b. The hydrogen supply section 74 supplies hydrogen to the space (first space 37a) closest to the compression chamber 34 side in the adapter section 37. In the hydrogen supply section 74, there is provided: a hydrogen valve 74b formed of a valve capable of adjusting the opening degree.

[0090] In addition, in the Figure 10 configuration, there is provided: another hydrogen supply section 76 that supplies hydrogen to the connecting rod seal section 36. In the another hydrogen supply section 76, there is provided: another valve 76b formed of a valve capable of adjusting the opening degree.

[0091] The nitrogen supply section 60 supplies nitrogen to the space (second space 37b) closest to the crank mechanism 14 side in the adapter section 37. In the nitrogen supply section 60, there is provided: a nitrogen valve 60b formed of a valve capable of adjusting the opening degree. In the intermediate chamber 37c between the first space 37a and the second space 37b, there is provided: a bleed discharge section 77 that discharges the gas inside the intermediate chamber 37c to the outside. In the bleed discharge section 77, there is provided: a valve 77a that opens when the pressure in the intermediate chamber 37c exceeds a specified pressure.

[0092] In addition, at least one of the hydrogen valve 74b and the nitrogen valve 60b is adjusted such that the pressure of hydrogen in the first space 37a and the pressure of nitrogen in the second space 37b are higher than the pressure inside the intermediate chamber 37c. Therefore, even if nitrogen may flow into the intermediate chamber 37c, it is possible to prevent the nitrogen from invading into the first space 37a.

[0093] In the third embodiment, even if nitrogen leaks from the space closest to the crank mechanism side into the intermediate chamber 37c, it is difficult for the nitrogen to reach the space closest to the compression chamber side. Therefore, it is possible to more reliably prevent nitrogen from mixing into the cylinder part 31.

[0094] The description of other configurations, operations, and effects is omitted, but the descriptions of the first to second embodiments can be cited for the third embodiment.

[0095] The embodiments disclosed this time should be construed as illustrative in all respects and not restrictive. The present invention is not limited to the above-described embodiments, and various changes, improvements, etc. can be made without departing from the scope of its gist.

[0096] Here, an overview of the above-described embodiments is given.

[0097] (1) The compressor unit according to the above-described embodiment is a reciprocating compressor unit that recovers evaporated gas, i.e., hydrogen, from a liquefied hydrogen storage tank via an inhalation flow path and supplies at least a part of the hydrogen to a demand side including at least one of an engine, a power generation device, and a boiler. The reciprocating compressor unit includes: a compression section that compresses the hydrogen in the inhalation flow path; and a crank mechanism that drives the compression section. The compression section includes: a cylinder part; a piston; a piston connecting rod that connects the piston to the crank mechanism; a connecting rod sealing section that seals between the piston connecting rod and the cylinder part; an adapter section that connects the cylinder part to the housing of the crank mechanism; a nitrogen supply section that supplies nitrogen into the adapter section; a leaked gas discharge section that discharges hydrogen leaked into the connecting rod sealing section to the outside; and a hydrogen supply section that supplies hydrogen to the connecting rod sealing section. The connecting rod sealing section includes: at least one sealing ring section that contacts the piston connecting rod and seals between the piston connecting rod and the cylinder part; a discharge passage that is connected to the leaked gas discharge section and allows a part of the gas compressed in the cylinder part, which is hydrogen leaked through the sealing ring section, to flow into the leaked gas discharge section; a gas sealing section that forms a gas seal in the gap between the piston connecting rod and the connecting rod sealing section based on the supply of hydrogen from the hydrogen supply section at a position on the crank mechanism side with respect to the discharge passage; and at least one other sealing ring section that is disposed between the gas sealing section and the discharge passage. The pressure of hydrogen in the gas sealing section is higher than the pressure of hydrogen in the leaked gas discharge section.

[0098] In the compressor unit, a discharge channel is provided in the connecting rod sealing portion, and the discharge channel is connected to the leakage gas discharge portion. Therefore, the hydrogen leaked through the sealing ring portion can be discharged to the outside through the discharge channel and the leakage gas discharge portion. In addition, a hydrogen-based gas seal portion is provided in the connecting rod sealing portion and on the crankcase side relative to the discharge channel, and the pressure of the hydrogen in the gas seal portion is higher than the pressure in the leakage gas discharge portion. Thus, the low-temperature gas compressed in the cylinder portion, that is, the evaporated gas (intake gas) of liquefied hydrogen, can be prevented from passing through the gas seal portion and invading the connector portion side and the crankcase side, thereby preventing the nitrogen from liquefying.

[0099] Furthermore, hydrogen is used in the gas seal of the connecting rod seal portion. Therefore, even if the sealing gas leaks into the cylinder portion, compared with the case where a different type of gas is used as the sealing gas, unexpected situations such as liquefaction caused by cooling of the sucked gas (hydrogen) can be prevented.

[0100] (2) In the compressor unit, the pressure of the hydrogen gas in the gas seal portion may be higher than the pressure of the nitrogen gas in the adapter portion.

[0101] In this configuration, the pressure of the hydrogen gas in the gas seal portion provided in the connecting rod seal portion is higher than the pressure of the nitrogen gas in the adapter portion. Therefore, it is possible to prevent the nitrogen gas supplied to the adapter portion from passing over the gas seal portion provided in the connecting rod seal portion. Therefore, it is possible to more reliably prevent the leakage gas of the boil-off gas (intake gas) of the liquefied hydrogen, which is the cryogenic gas compressed in the cylinder portion, from directly contacting the nitrogen gas.

[0102] (3) The compression section may further include another hydrogen supply unit capable of supplying hydrogen. In this case, the connector unit may include a partition unit that divides the interior of the connector unit into a space on the compression chamber side and a space on the crank mechanism side. In addition, the other hydrogen supply unit may be configured to supply hydrogen to the space on the compression chamber side, and the nitrogen supply unit may be configured to supply nitrogen to the space on the crank mechanism side. The temperature of the hydrogen in the space on the compression chamber side may be higher than the liquefaction temperature of the nitrogen in the space on the crank mechanism side.

[0103] In this configuration, since the adapter portion includes the spacer portion, it is possible to more reliably prevent the low-temperature boil-off gas (intake gas) from contacting the nitrogen gas. Since the temperature of the hydrogen gas in the space on the compression chamber side supplied by another hydrogen gas supply portion is higher than the liquefaction temperature of the nitrogen gas in the space on the crank mechanism side, it is possible to prevent the nitrogen gas from liquefying.

[0104] (4) The compression section may further include: a pressure adjustment unit that adjusts the gas pressure based on at least one of the hydrogen supply section, the other hydrogen supply section, and the nitrogen supply section in such a manner that a relationship of pressure P1 > pressure P2 > pressure P3 is established among the pressure P1 of hydrogen in the gas seal section, the pressure P2 of hydrogen in the space on the compression chamber side of the adapter section, and the pressure P3 of nitrogen in the space on the crank mechanism side.

[0105] In this configuration, since nitrogen does not flow from the space on the crank mechanism side into the space on the compression chamber side, nitrogen does not flow into the connecting rod seal section. Therefore, liquefaction of nitrogen can be prevented.

[0106] (5) The adapter section may further include: a supply port and a discharge port for nitrogen, which are arranged on the outer peripheral wall forming the space on the crank mechanism side; and a release side pressure adjustment unit that can release nitrogen when the pressure at the discharge port is equal to or higher than a specified pressure. In this case, the compression section may further include: a supply side pressure adjustment unit that adjusts the gas pressure based on at least one of the hydrogen supply section, the other hydrogen supply section, and the nitrogen supply section in such a manner that a relationship of pressure P1 > pressure P3 > pressure P2 is established among the pressure P1 of hydrogen in the gas seal section, the pressure P3 in the space on the crank mechanism side, and the pressure P2 of hydrogen in the space on the compression chamber side of the adapter section.

[0107] In this configuration, leakage of hydrogen, which is a flammable gas, to the crankcase side can be more actively prevented.

[0108] (6) The leaked gas discharge section may be configured to be connected to the suction flow path and return the leaked hydrogen to the suction flow path. In this case, the compression section may further include: a delivery pipeline that connects the hydrogen supply section to the discharge flow path and delivers a part of the hydrogen discharged from the compression section and flowing in the discharge flow path to the gas seal section.

[0109] In this configuration, leaked hydrogen can be recovered. In addition, there is no need to separately prepare hydrogen for gas sealing.

[0110] (7) The compressor unit involved in the described embodiment is a reciprocating compressor unit that recovers evaporated gas, i.e., hydrogen, from a liquefied hydrogen storage tank via an intake passage and supplies at least a part of the hydrogen to a demand side including at least one of an engine, a power generation device, and a boiler. The reciprocating compressor unit includes: a compression section that compresses the hydrogen in the intake passage; and a crank mechanism that drives the compression section. The compression section includes: a cylinder part; a piston; a piston connecting rod that connects the piston to the crank mechanism; a connecting rod seal part that seals between the piston connecting rod and the cylinder part; an adapter part that connects the cylinder part to the housing of the crank mechanism; a nitrogen supply part that supplies nitrogen to the inside of the adapter part; a hydrogen supply part that supplies hydrogen to other parts inside the adapter part; and a leaked gas discharge part that discharges the hydrogen leaked to the connecting rod seal part to the outside. The connecting rod seal part includes: at least one seal ring part that contacts the piston connecting rod and seals between the piston connecting rod and the cylinder part; a discharge passage that connects to the leaked gas discharge part and allows a part of the gas compressed in the cylinder part, which is hydrogen leaked through the seal ring part, to flow into the leaked gas discharge part; and at least one other seal ring part that is arranged on the side of the crank mechanism with respect to the discharge passage. The adapter part includes a partition part that divides the inside of the adapter part into a plurality of spaces. The hydrogen supply part is configured to supply hydrogen to the space closest to the compression chamber inside the adapter part. The nitrogen supply part is configured to supply nitrogen to at least one space inside the adapter part that is on the side of the crank mechanism with respect to the space closest to the compression chamber. The pressure of the hydrogen in the space closest to the compression chamber is higher than the pressure of the hydrogen in the leaked gas discharge part.

[0111] In the compressor unit, hydrogen is supplied to the space closest to the compression chamber inside the adapter part through the hydrogen supply part. The pressure of the hydrogen in the space closest to the compression chamber is higher than the pressure of the hydrogen in the leaked gas discharge part. Therefore, it is possible to prevent the hydrogen leaked to the connecting rod seal part from invading the space closest to the compression chamber in the adapter part. Thereby, it is possible to prevent the evaporated gas of the cryogenic gas, i.e., liquefied hydrogen, from directly contacting nitrogen and prevent the nitrogen from liquefying.

[0112] (8) The compression section may further include: another hydrogen supply part that supplies hydrogen to the connecting rod seal part. In this case, the connecting rod seal part may further include: a gas seal part that forms a gas seal in the gap between the piston connecting rod and the connecting rod seal part based on supplying hydrogen from the another hydrogen supply part to the part on the side of the crank mechanism with respect to the discharge passage. In addition, a part of the at least one other seal ring part may exist between the gas seal part and the discharge passage, and the pressure of the hydrogen in the gas seal part may be higher than the pressure of the hydrogen in the leaked gas discharge part.

[0113] In this configuration, the gas sealing portion can prevent leakage gas from the inside of the cylinder portion.

[0114] (9) The spacer portion may include two spacer members that divide the inside of the adapter portion into three spaces. In this case, the hydrogen supply portion may be configured to supply hydrogen to the space closest to the compression chamber side inside the adapter portion, and the nitrogen supply portion may be configured to supply nitrogen to the space closest to the crank mechanism side inside the adapter portion. A gas discharge portion for discharging the gas inside the intermediate chamber to the outside may be provided in the intermediate chamber of the adapter portion. In addition, the pressure of hydrogen in the space closest to the compression chamber side and the pressure of nitrogen in the space closest to the crank mechanism side may be set higher than the pressure inside the intermediate chamber.

[0115] In this configuration, even if nitrogen leaks from the space closest to the crank mechanism side into the intermediate chamber, it is difficult for this nitrogen to reach the space closest to the compression chamber side. Therefore, it is possible to more reliably prevent nitrogen from mixing into the cylinder portion.

[0116] (10) The leakage gas discharge portion may be configured to be connected to the suction flow path and return the leaked hydrogen to the suction flow path. In this case, the compression section may further include a transfer pipeline that connects the other hydrogen supply portion to the discharge flow path and transfers a part of the hydrogen discharged from the compression section and flowing in the discharge flow path to the gas sealing portion.

[0117] In this configuration, the leaked hydrogen can be recovered. In addition, it is not necessary to separately prepare hydrogen for gas sealing.

[0118] (11) Nitrogen may be supplied to the inside of the adapter portion by the nitrogen supply portion not only during the operation of the compression section but also during the stop of the compression section.

[0119] The components of the compression section, namely the cylinder portion, the piston, and the piston connecting rod, become low temperature during operation and do not immediately return to normal temperature even when the compressor unit stops, and the state of being at low temperature continues for a long time. On the other hand, when the supply of nitrogen is stopped, the atmosphere may invade the space on the crank mechanism side of the adapter portion. When the piston connecting rod is in a low temperature state and the atmosphere invades the space on the crank mechanism side, condensation may occur on the piston connecting rod. In this case, rusting of the internal components and / or adhesion of condensation on the surface of the piston connecting rod may cause the sealing ring to damage the sealing function. However, since nitrogen is supplied not only during the operation of the compression section but also during the stop, it is possible to prevent rusting of the internal components and deterioration of the sealing function.

[0120] As described above, a sealing structure suitable for a reciprocating compressor unit using boil-off gas of liquefied hydrogen can be achieved.

Claims

1. A reciprocating compressor unit, characterized in that, Evaporated gas, i.e., hydrogen, is recovered from the liquefied hydrogen storage tank via the suction flow path, and at least a part of the hydrogen is supplied to a demand side including at least one of an engine, a power generation device, and a boiler. The reciprocating compressor unit includes: a compression section that compresses the hydrogen in the suction flow path; and, a crank mechanism that drives the compression section; wherein, the compression section includes: a cylinder part; a piston; a piston connecting rod that connects the piston to the crank mechanism; a connecting rod sealing part that seals between the piston connecting rod and the cylinder part; an adapter part that connects the cylinder part to the housing of the crank mechanism; a nitrogen supply part that supplies nitrogen to the inside of the adapter part; a leakage gas discharge part that discharges hydrogen leaked into the connecting rod sealing part to the outside; and, a hydrogen supply part that supplies hydrogen to the connecting rod sealing part; wherein, the connecting rod sealing part includes: at least one sealing ring part that contacts the piston connecting rod and seals between the piston connecting rod and the cylinder part; a discharge passage that is connected to the leakage gas discharge part and allows a part of the gas compressed in the cylinder part, i.e., hydrogen leaked through the sealing ring part, to flow into the leakage gas discharge part; a gas sealing part that forms a gas seal in the gap between the piston connecting rod and the connecting rod sealing part based on the supply of hydrogen from the hydrogen supply part at a position on the crank mechanism side with respect to the discharge passage; and, at least one other sealing ring part that is arranged between the gas sealing part and the discharge passage; wherein, the pressure of the hydrogen in the gas sealing part is higher than the pressure of the hydrogen in the leakage gas discharge part.

2. The reciprocating compressor unit according to claim 1, characterized in that, the pressure of the hydrogen in the gas sealing part is higher than the pressure of the nitrogen in the adapter part.

3. The reciprocating compressor unit according to claim 1 or 2, characterized in that, The compression section further includes another hydrogen supply part capable of supplying hydrogen. The adapter part includes a partition part that divides the inside of the adapter part into a space on the compression chamber side and a space on the crank mechanism side. The other hydrogen supply part is configured to supply hydrogen to the space on the compression chamber side. The nitrogen supply part is configured to supply nitrogen to the space on the crank mechanism side. The temperature of the hydrogen in the space on the compression chamber side is higher than the liquefaction temperature of the nitrogen in the space on the crank mechanism side.

4. The reciprocating compressor unit according to claim 3, characterized in that, The compression section further includes: a pressure adjustment unit that adjusts the gas pressure based on at least one of the hydrogen supply part, the other hydrogen supply part, and the nitrogen supply part so that a relationship of pressure P1 > pressure P2 > pressure P3 is established among the pressure P1 of the hydrogen in the gas sealing part, the pressure P2 of the hydrogen in the space on the compression chamber side of the adapter part, and the pressure P3 of the nitrogen in the space on the crank mechanism side.

5. The reciprocating compressor unit according to claim 3, characterized in that, The adapter part further includes: a supply port and a discharge port for nitrogen, which are arranged on the outer peripheral wall forming the space on the crank mechanism side; and, a release side pressure adjustment unit that can release nitrogen when the pressure at the discharge port is above a specified pressure. The compression section further includes: A supply-side pressure adjustment unit adjusts the gas pressure based on at least one of the hydrogen supply unit, the other hydrogen supply unit, and the nitrogen supply unit in such a manner that a relationship of pressure P1 > pressure P3 > pressure P2 is established among the pressure P1 of hydrogen in the gas seal portion, the pressure P2 of hydrogen in the space on the compression chamber side of the adapter portion, and the pressure P3 in the space on the crank mechanism side.

6. The reciprocating compressor unit according to claim 1, wherein, The leaked gas discharge portion is configured to be connected to the suction passage and return the leaked hydrogen to the suction passage. The compression section further includes: A delivery pipeline connects the hydrogen supply unit to the discharge passage and delivers a part of the hydrogen discharged from the compression section and flowing in the discharge passage to the gas seal portion.

7. A reciprocating compressor unit, characterized in that, Evaporation gas, i.e., hydrogen, is recovered from the liquefied hydrogen storage tank via the suction passage, and at least a part of the hydrogen is supplied to a demand side including at least one of an engine, a power generation device, and a boiler. The reciprocating compressor unit includes: A compression section that compresses the hydrogen in the suction passage; and A crank mechanism that drives the compression section; wherein The compression section includes: A cylinder portion; A piston; A piston connecting rod that connects the piston to the crank mechanism; A connecting rod seal portion that seals between the piston connecting rod and the cylinder portion; An adapter portion that connects the cylinder portion to the housing of the crank mechanism; A nitrogen supply unit that supplies nitrogen to the inside of the adapter portion; A hydrogen supply unit that supplies hydrogen to other parts inside the adapter portion; and A leaked gas discharge portion that discharges the hydrogen leaked into the connecting rod seal portion to the outside; wherein The connecting rod seal portion includes: At least one seal ring portion that contacts the piston connecting rod and seals between the piston connecting rod and the cylinder portion; A discharge passage that is connected to the leaked gas discharge portion and allows a part of the gas compressed in the cylinder portion and the hydrogen leaked through the seal ring portion to flow into the leaked gas discharge portion; and At least one other seal ring portion that is disposed on the crank mechanism side with respect to the discharge passage. The adapter portion includes a partition portion that divides the inside of the adapter portion into a plurality of spaces. The hydrogen supply unit is configured to supply hydrogen to the space closest to the compression chamber inside the adapter portion. The nitrogen supply unit is configured to supply nitrogen to at least one space on the crank mechanism side with respect to the space closest to the compression chamber inside the adapter portion. The pressure of hydrogen in the space closest to the compression chamber is higher than the pressure of hydrogen in the leaked gas discharge portion.

8. The reciprocating compressor unit according to claim 7, wherein, The compression section further includes: Another hydrogen supply unit that supplies hydrogen to the connecting rod seal portion. The connecting rod seal portion further includes: A gas seal portion that forms a gas seal in the gap between the piston connecting rod and the connecting rod seal portion by supplying hydrogen from the other hydrogen supply unit to the portion on the crank mechanism side with respect to the discharge passage. A part of the at least one other seal ring portion is present between the gas seal portion and the discharge passage. The pressure of hydrogen in the gas seal part is higher than the pressure of hydrogen in the leaked gas discharge part.

9. The reciprocating compressor unit according to claim 7, wherein, The partition part includes two partition members that divide the inside of the adapter part into three spaces. The hydrogen supply part is configured to supply hydrogen to the space closest to the compression chamber side inside the adapter part. The nitrogen supply part is configured to supply nitrogen to the space closest to the crank mechanism side inside the adapter part. An air release discharge part for discharging the gas inside the intermediate chamber to the outside is provided in the intermediate chamber of the adapter part. The pressure of hydrogen in the space closest to the compression chamber side and the pressure of nitrogen in the space closest to the crank mechanism side are set to be higher than the pressure inside the intermediate chamber.

10. The reciprocating compressor unit according to claim 8, characterized in that, The leaked gas discharge part is configured to be connected to the suction flow path and return the leaked hydrogen to the suction flow path. The compression section further includes: A transfer pipeline that connects the other hydrogen supply part to the discharge flow path and transfers a part of the hydrogen discharged from the compression section and flowing in the discharge flow path to the gas seal part.

11. A method for operating a compressor unit, characterized in that The operating method of the reciprocating compressor unit according to claim 1 or 7, wherein: Nitrogen is supplied to the inside of the adapter part by the nitrogen supply part not only during the operation of the compression section but also during the stop of the compression section.

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