CN115298497A

CN115298497A - Liquefaction and subcooling system and method

Info

Publication number: CN115298497A
Application number: CN202180022687.7A
Authority: CN
Inventors: 弗雷德里克·马尔库奇利; N·布伦纳
Original assignee: Cryostar SAS
Current assignee: Cryostar SAS
Priority date: 2020-04-08
Filing date: 2021-03-29
Publication date: 2022-11-04
Also published as: JP2023520766A; EP4133226A1; US20230160632A1; KR20220165253A; WO2021204420A1

Abstract

A liquefaction and subcooling system is provided, in particular for a boil-off gas management system, for liquefying different first and second gases having different saturation temperatures at a given pressure. The system comprises: a refrigeration device (10) operable to alternately provide a refrigerant fluid at a first and a second low temperature corresponding to different liquefaction temperatures of a first and a second gas, a subcooling arrangement (50) coupled to the refrigeration device such that the refrigerant fluid is supplied to the subcooling arrangement at its low temperature, the subcooling arrangement having first and second subcoolers (70, 72) for heat exchange between the gas to be liquefied and/or subcooled and the refrigerant fluid, wherein, when the gas to be liquefied and/or subcooled is the first gas, the refrigeration device is configured to provide the refrigerant fluid at the first low temperature, and the subcooling arrangement is configured to direct the refrigerant fluid and the gas through the first subcooler (70); and, when the gas to be liquefied and/or subcooled is a second gas, the refrigeration device is configured to provide the refrigerant fluid at a second low temperature, and the subcooling arrangement is configured to direct the refrigerant fluid and the gas through a second subcooler (72). A corresponding method and boil-off gas management system are also provided.

Description

Liquefaction and subcooling system and method

The present invention relates to storage and transportation of liquefied gases. In particular, the invention relates to the management and re-liquefaction and sub-cooling of boil-off gases of different liquefied gases alternately stored and/or transported in the same plant.

Background

Liquefied gases, such as liquefied ethane or Liquefied Natural Gas (LNG), when transported by liquefied gas carriers, such as floating carriers, are typically stored in atmospheric storage tanks under saturated conditions. In the tank, the liquefied gas evaporates because the tank is inevitably not fully insulated. This vaporized gas is referred to as boil-off gas (BOG). While some BOGs may be used to power the engines of gas carriers, not all BOGs are typically available in this manner. Therefore, liquefied gas carriers have a BOG management system for reliquefying BOG in order to avoid a pressure rise in the storage tank or to avoid the discharge of BOG to the atmosphere. Such BOG management systems are known; see, e.g., US 20140102133 A1.

The temperature of liquefied gas stored in an atmospheric tank under saturated conditions varies widely for different gases. For example, the temperature level of liquefied ethane in the storage tank is around-90 ℃ and the temperature level of LNG in the storage tank is around-160 ℃. Known BOG management systems are generally unable to reliquefy different gases that have large saturation temperature differences at atmospheric pressure and require large differences in the low temperatures of the refrigerant fluids used for reliquefaction.

At present, large gas carriers are planned to transport up to 18 million cubic meters of gas. For example, excess ethane is a by-product of U.S. shale gas, which is transported from north america to europe by such transport vessels. However, the construction of ethane transport vessels requires a significant investment, and it is therefore desirable that it also be able to transport LNG to provide a higher degree of flexibility, particularly under uncertain market conditions.

It is therefore an object of the present invention to provide a liquefaction and subcooling system which can operate effectively at different temperature levels, in particular which should be suitable for use in a boil-off gas management system for reliquefying and subcooling a boil-off gas.

Disclosure of Invention

A liquefaction and subcooling system for liquefying and subcooling different first and second gases having different saturation temperatures at a given pressure, a boil-off gas management system, and a method for liquefying and subcooling different first and second gases having different saturation temperatures at a given pressure are provided according to the independent claims. The dependent claims and the following description relate to preferred embodiments.

A liquefaction and subcooling system for liquefying different first and second gases having different saturation temperatures at a given pressure, comprising: a refrigeration device operable to alternately provide a refrigerant fluid at a first low temperature and a second low temperature corresponding to different liquefaction temperatures of a first gas and a second gas, a subcooling arrangement coupled to the refrigeration device such that the refrigerant fluid is supplied to the subcooling arrangement at its low temperature, the subcooling arrangement having a first subcooler and a second subcooler for heat exchange between the gas to be liquefied and/or subcooled and the refrigerant fluid, wherein, when the gas to be liquefied and/or subcooled is the first gas, the refrigeration device is configured to provide the refrigerant fluid at the first low temperature, and the subcooling arrangement is configured to direct the refrigerant fluid and the gas to be liquefied and/or subcooled through the first subcooler; and, when the gas to be liquefied and/or subcooled is a second gas, the refrigeration device is configured to provide the refrigerant fluid at a second low temperature, and the subcooling arrangement is configured to direct the refrigerant fluid and the gas to be liquefied and/or subcooled through the second subcooler. The term "liquefaction temperature" is used herein to indicate the low temperature required to liquefy a gas at a given pressure. After liquefaction (or after having been in a previous compression stage) a liquid state of the gas is obtained, which may be further cooled below the liquefaction temperature, i.e. may be subcooled. Thus, the process typically includes liquefaction and/or subcooling. For the sake of simplicity, the expression "gas to be liquefied and/or to be subcooled" is used to mean that the subcooling part in this expression relates to the (re) liquefied gas, i.e. the "gas to be subcooled" part in the expression means that the (re) liquefied (in the liquid state) gas is subcooled (cooled below the liquefaction temperature, cooled below the condensation temperature).

The liquefaction and subcooling system may be used in particular in Boil Off Gas (BOG) management systems for liquefied gas storage or transportation devices at atmospheric temperature, i.e. for liquefied gas storage tanks. Although the gas is "reliquefied" in the BOG management system, for simplicity and since the previous state of the gas is not a requirement for practicing the present invention, the terms "liquefied", "liquefy", and "liquefy" are used throughout this patent application.

The liquefaction and subcooling system according to the invention advantageously allows the use of a common single refrigeration system (refrigeration plant) that liquefies different gases, in particular for managing the different evaporation gases. In particular, rotating machinery is common, and refrigerants are common, and switching between different gases can be accomplished by a simple set of on/off valves.

According to this solution, the provision of two different subcoolers allows different gases to be liquefied. The liquefaction and subcooling systems can be switched between only two conditions. This means that a storage facility for liquefied gas (e.g. located on a gas carrier) can be used for different gases without having to provide a different reliquefaction and BOG management system for each gas, only the subcooling arrangement needs to be changed.

Preferably, the first subcooler is configured for heat exchange between the first gas to be liquefied and/or subcooled and the refrigerant fluid at a first low temperature, and the second subcooler is configured for heat exchange between the second gas to be liquefied and/or subcooled and the refrigerant fluid at a second low temperature. Specifically, the subcooler is selected or designed to achieve a large amount of heat exchange at the corresponding temperature level of each gas. This may overcome the mechanical constraints imposed on the subcooler (heat exchanger) operating at different temperature levels, i.e. may overcome the problem that a heat exchanger designed to operate at a certain temperature may not be suitable for efficient operation at different temperatures. The first subcooler and the second subcooler may be used interchangeably. The first subcooler and the second subcooler are essentially heat exchangers and may be one of the following types: shell and tube heat exchangers, plate and shell heat exchangers or plate and fin heat exchangers, preferably plate and fin heat exchangers are used.

According to one embodiment, the liquefaction and subcooling system may comprise a multi-stream heat exchanger, wherein the heat exchanger of the refrigeration plant is formed, and wherein the first subcooler and the second subcooler are formed by separate conduits.

According to one embodiment, the subcooling arrangement may comprise a combined subcooler formed by a heat exchanger, wherein the first subcooler and the second subcooler are formed by separate conduits.

According to one embodiment, the first subcooler and the second subcooler may be separate heat exchangers. Preferably, the two separate heat exchangers are of two different types selected from the following types: shell and tube heat exchangers, plate and shell exchangers and plate and fin heat exchangers.

According to one embodiment, the first subcooler and/or the second subcooler may be formed by a plate-fin heat exchanger.

According to one embodiment, the refrigerant fluid may be selected from helium, nitrogen, methane, ethane, neon, or combinations thereof. According to one embodiment, the first cryogenic temperature may be in the range of-120 ℃ to-85 ℃, preferably-115 ℃, and the second cryogenic temperature may be in the range of-183 ℃ to-155 ℃, preferably-178 ℃. Preferably, the difference between the first low temperature and the second low temperature is at least 30 ℃, preferably at least 40 ℃, most preferably at least 50 ℃. Preferably, the difference between the first low temperature and the second low temperature is in the range of 30 ℃ to 100 ℃, more preferably in the range of 40 ℃ to 80 ℃, most preferably in the range of 50 ℃ to 70 ℃.

According to one embodiment, the first gas may be ethane and the second gas may be natural gas. The same principle applies to ammonia or LPC carriers.

The boil-off gas management system comprises one of the liquefaction and subcooling systems described above, wherein the liquefaction and subcooling system is arranged to reliquefy and/or subcool the boil-off gas.

A method for liquefying different first and second gases having different saturation temperatures at a given pressure comprises: a refrigeration device is provided which is operable to alternately provide a refrigerant fluid at a first low temperature and a second low temperature corresponding to different liquefaction temperatures of the first gas and the second gas, and when the gas to be liquefied and/or subcooled is the first gas, to provide the refrigerant fluid at the first low temperature and to direct the gas to be liquefied and/or subcooled through the first subcooler for heat exchange with the refrigerant fluid, and when the gas to be liquefied and/or subcooled is the second gas, to provide the refrigerant fluid at the second low temperature and to direct the gas to be liquefied and/or subcooled through the second subcooler for heat exchange with the refrigerant fluid.

It is noted that any of the features described above in connection with the liquefaction and subcooling systems are also applicable to the method according to the invention.

Drawings

The present invention will become more fully understood from the following description, which refers to the accompanying drawings, wherein:

FIG. 1 is a schematic diagram illustrating the structure and operation of an embodiment of a liquefaction and subcooling system according to the invention;

FIG. 2 is a schematic diagram showing the structure and operation of another embodiment of a liquefaction and subcooling system according to the invention;

FIG. 3 is a schematic diagram showing the structure and operation of another embodiment of a liquefaction and subcooling system according to the invention;

FIG. 4 is a schematic diagram of a boil-off gas management system according to an embodiment of the invention; and is

Fig. 5 is a flow diagram illustrating an embodiment of a liquefaction process according to the present invention.

Detailed Description

A schematic diagram of a liquefaction and subcooling system according to the first embodiment of the present invention is shown in figure 1. The liquefaction and subcooling system includes a refrigeration device 10 (which forms a refrigeration subsystem of the liquefaction and subcooling system) and a subcooling arrangement 50 (which forms a heat exchange subsystem of the liquefaction and subcooling system). The refrigeration device is operable to provide a refrigerant fluid at each of at least two different temperatures, a first cryogenic temperature and a second cryogenic temperature. In general, a refrigeration device may be operable such that a refrigerant fluid is provided at any temperature within a temperature range that depends on the structure or type of the refrigeration device, i.e. on the ability of the refrigeration device to cool the refrigerant fluid to a certain low temperature. The first cryogenic temperature corresponds to a temperature for liquefying the first gas (e.g., ethane) and the second cryogenic temperature corresponds to a temperature for liquefying the second gas (e.g., LNG). The temperature used to liquefy the gas is herein also indicated as liquefaction temperature.

In the refrigeration unit, a working circuit 12 of refrigerant fluid is formed. The work circuit 12 includes a compression section, an expansion section, and a heat exchanger section. The compression section is formed, for example, by three

compressors

14, 16, 18, which are driven, for example, on a drive shaft by

motors

20, 22, 24. More generally, any number of compressors may be used, i.e., the compression section may generally include any number of compression stages. The

compressors

14, 16, 18 may be of the centrifugal compression type. In the working circuit 12, a cooler 26, 28, 30 is included after each of the

compressors

14, 16, 18 for cooling the refrigerant fluid to ambient temperature after each compression stage. The

coolers

26, 28, 30 are supplied with cooling fluid through conduits, as indicated by

arrows

32, 34, 36. For example, air, water or on board a marine vessel using sea water as the cooling fluid may be used.

The expansion section is formed by an expansion turbine 38, which may be of the centripetal expansion type. More generally, the expansion section may be formed by more than one expansion turbine. The expansion turbine 38 is driven by a motor 24, which in the embodiment shown in FIG. 1 is the same motor 24 that drives the compressor 18, for example. For efficiency reasons, both the expansion turbine 38 and the compressor 18 are driven on a common drive shaft. The refrigerant fluid exits the expansion turbine 38 at an outlet conduit 40 that is part of the work circuit 12. At this point (as soon as the expansion in the expansion turbine 38 is over), the refrigerant fluid has reached its minimum temperature, i.e., it has reached a low temperature. In other words, the refrigerant fluid is provided in the outlet conduit 40 by the refrigeration device at its low temperature.

The heat exchanger section of the refrigeration unit 10 is formed by a heat exchanger 42 in which heat is exchanged between the compressed refrigerant fluid downstream of the compression section and upstream of the expansion section and the expanded refrigerant fluid downstream of the expansion section and upstream of the compression section. In this way, the compressed refrigerant fluid cooled by cooler 30 to substantially ambient temperature is cooled to a lower (cryogenic) temperature by heat exchange with the refrigerant fluid at its lowest temperature downstream of the expansion section (expansion turbine 38) before being directed through heat exchanger 42. To facilitate understanding of the different embodiments, elliptical lines are drawn around the conduits exchanging heat, and reference numerals are attached to the lines to indicate the corresponding heat exchangers. This is the case for the heat exchanger 42 of the refrigeration unit and the first subcooler 70 and second subcooler 72 described below.

It is noted that the particular construction of the refrigeration unit 10 is not essential to the practice of the present invention. The key point is that the refrigeration device is operable so that refrigerant fluid can be provided at different low temperatures. In the exemplary embodiment shown in fig. 1, this may be accomplished by driving the

compressors

14, 16, 18 and the expansion turbine 38 accordingly, i.e., at different speeds and electrical power.

Additionally, a bypass valve 44 may be provided that allows refrigerant fluid to bypass the heat exchanger 42 via a conduit.

In the subcooling arrangement 50, a gas stream to be liquefied and/or subcooled is provided at an inlet 52, passed through the subcooling arrangement for cooling, and exits the subcooling arrangement at an outlet 54, preferably in a liquid state. The subcooling arrangement 50 has two different flow paths for the gas to be liquefied and/or subcooled, a first flow path 56 and a second flow path 58. The flow path of the gas to be liquefied and/or subcooled may be selected accordingly by the switching valve. Specifically, when valves 60, 62 are open and valves 64 and 66 are closed, the gas to be liquefied and/or subcooled flows through the first flow path 56. When the valves 64, 66 are open and the valves 60, 62 are closed, the gas to be liquefied and/or sub-cooled flows through the second flow path 58.

The gas to be liquefied and/or subcooled will typically be provided in compressed form and may be at least partly in liquid state. In particular, the BOG is typically directed through a compression stage before being fed to the inlet 52 by the BOG management system.

A first subcooler 70 is provided in the first flow path 56 and a second subcooler 72 is provided in the second flow path 58. The first subcooler 70 is configured to effectively exchange heat between the first gas to be liquefied and/or subcooled and the refrigerant fluid at the first low temperature. The second subcooler 70 is configured to efficiently exchange heat between the second gas to be liquefied and/or subcooled and the refrigerant fluid at the second low temperature. The first subcooler 70 and the second subcooler 72 are heat exchangers, preferably plate fin heat exchangers.

Specific to the embodiment shown in fig. 1 are: the heat exchanger 42, the first subcooler 70 and the second subcooler 72 of the refrigeration unit are formed in a single multi-stream heat exchanger 100 having different conduits. The multi-stream heat exchanger 100 is disposed downstream of the expansion section (expansion turbine 38) and is provided with refrigerant fluid at low temperature by the outlet conduit 40. The multi-stream heat exchanger 100 has two conduits 102, 104: one conduit 102 directs the refrigerant fluid through the heat exchanger 42 of the refrigeration unit and another conduit 104 directs the refrigerant fluid through the first subcooler 70 and the second subcooler 72. The first subcooler 70 and the second subcooler 72 are formed by different conduits in the multi-stream heat exchanger 100.

Valves

106, 108, 110, 112 are provided that control refrigerant fluid flow through the conduits 102, 104 of the multi-stream heat exchanger 100.

When the gas to be liquefied and/or subcooled is a first gas, the refrigerant fluid is provided at a first cryogenic temperature and the gas is directed through a first flow path 56 comprising a conduit forming a first subcooler 70 in a multi-stream heat exchanger 100. When the gas to be liquefied and/or subcooled is a second gas, the refrigerant fluid is provided at a second low temperature and the gas is directed through a second flow path 58 comprising a conduit forming a second subcooler 72 located in the multi-stream heat exchanger 100. In both cases, the valve 108 should be open, wherein the valve 108 controls the flow of refrigerant fluid to the conduit 104 that is directed through the first subcooler and the second subcooler 72.

Additionally, a bypass valve 68 may be provided that allows for a direct connection of the inlet 52 with the outlet 54, which may be useful, for example, when performing maintenance of the multi-stream heat exchanger 100.

It should be apparent that additional structures or elements may be included in the work circuit 12 and/or the first and

second flow paths

56, 58, such as makeup valves, flow meters, pressure sensors, and the like.

Fig. 2 shows a liquefaction and subcooling system according to another embodiment of the present invention. In order to avoid repetition, a description of a structure common to the embodiment shown in fig. 1 will not be repeated hereinafter, and common elements will be denoted by the same reference numerals. Thus, unless otherwise indicated, the description of fig. 1 applies to these elements, with the differences noted below.

The difference between the embodiments of fig. 1 and 2 is the different arrangement of the heat exchanger, in particular the subcooling arrangement 50; specifically the heat exchanger 42 of the refrigeration unit 10, and specifically the first subcooler 70 and the second subcooler 72 of the subcooling arrangement 50.

The heat exchanger 42 of the refrigeration unit is formed by a conventional counter-flow heat exchanger 200. The first subcooler 70 and the second subcooler 72 of the subcooling arrangement 50 are formed as a combined subcooler (combined heat exchanger) 202. The combined subcooler 202 is basically a heat exchanger that combines the heat exchangers constituting the first subcooler 70 and the second subcooler 72. The combined subcooler 202 is separate from the counter-flow heat exchanger 200, i.e., the combined subcooler 202 is dedicated to subcooling. A number of

valves

204, 206, 208 are disposed in the work circuit 12 for controlling the flow of refrigerant fluid to and from the combined subcooler 202 and counter-flow heat exchanger 200.

The combined subcooler 202 is disposed in the work circuit 12 between the expansion section and the heat exchanger section of the refrigeration unit 10, i.e., downstream of the expansion turbine 38 and upstream of the counter flow heat exchanger 200. From the expansion section outlet conduit 40, the refrigerant fluid is directed through a valve 204 into a single inlet 210 for the refrigerant fluid of the combined subcooler 202. The first subcooler 70 and the second subcooler 72 are formed by two separate conduits in the combined subcooler 202. The two separate conduits are arranged to exchange heat with a refrigerant fluid directed through the combined subcooler 202 by the other conduit. Two separate conduits form part of the first flow path 56 and the second flow path 58, respectively.

When the gas to be liquefied and/or subcooled is a first gas, the refrigerant fluid is provided at a first cryogenic temperature and the gas to be liquefied and/or subcooled is directed through a first flow path 56 comprising a conduit forming a first subcooler 70 in a combined subcooler 202. When the gas to be liquefied and/or subcooled is the second gas, the refrigerant fluid is provided at a second low temperature and the gas to be liquefied and/or subcooled is directed through the second flow path 58, which includes the conduit forming the second subcooler 72, in the combined subcooler 202. In both cases, the valve 204 should be open, wherein the valve 204 controls the flow of refrigerant fluid to the refrigerant fluid inlet 210 for the combined subcooler 202.

Fig. 3 shows a liquefaction and subcooling system according to another embodiment of the present invention. As already mentioned in connection with fig. 2, in order to avoid repetition, the description of the structure common to the embodiment shown in fig. 1 is not repeated below, and common elements are denoted with the same reference numerals. Thus, unless otherwise noted, the description of fig. 1 applies to these elements, with the differences noted below.

The difference between the embodiments of fig. 1 and 3 is the different arrangement of the heat exchanger, in particular the subcooling arrangement 50; specifically the heat exchanger 42 of the refrigeration unit 10, and specifically the first subcooler 70 and the second subcooler 72 of the subcooling arrangement 50.

The heat exchanger 42 of the refrigeration unit is formed by a conventional counter-flow heat exchanger 300. The first subcooler 70 and the second subcooler 72 of the subcooling arrangement are formed as two separate subcoolers (heat exchangers) that are also separate from the counter-flow heat exchanger 300. That is, the first subcooler 70 is formed by a first heat exchanger 302 and the second subcooler 72 is formed by a second heat exchanger 304, the second heat exchanger 304 being separate from the first heat exchanger 302. A number of valves 306, 308, 310, 312, 314 are disposed in the work circuit 12 for controlling the flow of refrigerant fluid to and from the first and second heat exchangers 302,304 and the counter flow heat exchanger 300.

A first heat exchanger 302 and a second heat exchanger 304 are arranged in parallel in the working circuit 12 between the expansion section and the heat exchanger section of the refrigeration device 10, i.e. downstream of the expansion turbine 38 and upstream of the counter flow heat exchanger 300. A valve 306 controls refrigerant fluid flow to the first heat exchanger 302 and another valve 308 controls refrigerant fluid flow to the second heat exchanger 304.

When the gas to be liquefied and/or subcooled is a first gas, the refrigerant fluid is provided at a first cryogenic temperature and the gas to be liquefied and/or subcooled is directed through the first flow path 56, which includes the first heat exchanger 302 forming the first subcooler 70. When the gas to be liquefied and/or subcooled is a second gas, the refrigerant fluid is provided at a second low temperature, and the gas to be liquefied and/or subcooled is directed through the second flow path 58, which includes the second heat exchanger 304 forming the second subcooler 72. In the first case (first gas to be liquefied and/or sub-cooled), valve 306 controlling the flow of refrigerant fluid to first heat exchanger 302 is open, while valve 308 controlling the flow of refrigerant fluid to second heat exchanger 304 is closed, and the second case (second gas to be liquefied and/or sub-cooled) is reversed.

FIG. 4 illustrates an exemplary Boil Off Gas (BOG) management system 400 for a storage tank 402 for a liquefied gas 404. In the storage tank 402, the BOG 408 occurs above the surface 406 of the liquefied gas 404 stored in the storage tank. BOG is pumped through a conduit to the inlet 52 of a liquefaction and subcooling system 412 according to the invention, which may be, for example, any of the liquefaction and subcooling systems shown in fig. 1-3. After liquefaction, the (re) liquefied and subcooled BOG is pumped back from the outlet 54 of the liquefaction and subcooling system 412 and reintroduced into the storage tank 402 in liquid form. Between the storage tank 402 and the inlet 52 of the liquefaction and subcooling system 412, a compressor 410 (such as shown in fig. 4) may be included in the conduit that compresses the BOG prior to (re) liquefying the BOG.

Fig. 5 shows a flow diagram of a method for liquefaction, according to an embodiment. The method comprises a step 510 of providing a refrigeration device operable to alternately provide a refrigerant fluid at a first cryogenic temperature and a second cryogenic temperature corresponding to different liquefaction temperatures of the first gas and the second gas. When the refrigeration device is capable of operating at a first cryogenic temperature and a second cryogenic temperature, the cryogenic temperature at which the refrigeration device operates may be selected according to the gas to be liquefied. The selection is made in a step 520 of selecting whether the first gas or the second gas is to be liquefied. When the gas to be liquefied and/or subcooled is the first gas, the method continues with the step 530 of operating the refrigeration unit to provide a refrigerant fluid at a first cryogenic temperature, and the step 540 of directing the gas to be liquefied and/or subcooled through a first subcooler for heat exchange with the refrigerant fluid. On the other hand, when the gas to be liquefied and/or subcooled is the second gas, the method continues with the step 550 of operating the refrigeration device to provide the refrigerant fluid at the second cryogenic temperature, and the step 560 of directing the gas to be liquefied and/or subcooled through the second subcooler for heat exchange with the refrigerant fluid. For embodiments of the method, reference is made to embodiments of the system according to the invention, which are correspondingly applied to the method according to the invention.

While the present invention has been described in terms of the embodiments and examples in the foregoing specification, the scope of the invention is limited by the appended claims, and not by the specific embodiments of this specification. It should be noted that elements of different embodiments may be combined even if not explicitly stated.

List of reference numerals

10. Refrigerating device

12. Working circuit

14. Compressor with a compressor housing having a plurality of compressor blades

16. Compressor with a compressor housing having a plurality of compressor blades

18. Compressor with a compressor housing having a plurality of compressor blades

20. Motor with a stator having a stator core

22. Motor with a stator and a rotor

24. Motor with a stator having a stator core

26. Cooling device

28. Cooling device

30. Cooling device

32. Supply of cooling fluid

34. Supply of cooling fluid

36. Supply of cooling fluid

38. Expansion turbine

40. Outlet duct

42. Heat exchanger

44. Bypass valve

50. Supercooling arrangement structure

52. Inlet port

54. An outlet

56. First flow path

58. Second flow path

60. Valve with a valve body

62. Valve with a valve body

64. Valve with a valve body

66. Valve with a valve body

68. Bypass valve

70. A first subcooler

72. Second subcooler

100. Multi-flow heat exchanger

102. Catheter tube

104. Catheter tube

106. Valve with a valve body

108. Valve with a valve body

110. Valve with a valve body

112. Valve with a valve body

200. Counterflow heat exchanger for a refrigeration device

202. Combined subcooler with supercooling arrangement structure

204. Valve with a valve body

206. Valve with a valve body

208. Valve with a valve body

210. Inlet for refrigerant fluid

300. Counterflow heat exchanger for a refrigerating device

302. First heat exchanger

304. Second heat exchanger

306. Valve with a valve body

308. Valve with a valve body

310. Valve with a valve body

312. Valve with a valve body

314. Valve with a valve body

400. Boil-off gas management system

402. Storage tank

404. Liquefied gas

406. Surface of liquefied gas

408. Boil-off gas

410. Compressor with a compressor housing having a plurality of compressor blades

412. A liquefaction and subcooling system.

Claims

1. Liquefaction and subcooling system, in particular for a boil-off gas management system, for liquefying and/or subcooling different first and second gases having different saturation temperatures at a given pressure, comprising

A refrigeration device (10) operable to alternately provide a refrigerant fluid at a first cryogenic temperature and a second cryogenic temperature corresponding to different liquefaction temperatures of the first and second gases;

a subcooling arrangement (50) coupled to the refrigeration device such that the refrigerant fluid is supplied to the subcooling arrangement at its low temperature, the subcooling arrangement having first and second subcoolers (70, 72) for heat exchange between a gas to be liquefied and/or subcooled and the refrigerant fluid;

wherein, when the gas to be liquefied and/or subcooled is the first gas, the refrigeration device (10) is configured to provide the refrigerant fluid at the first low temperature, and the subcooling arrangement (50) is configured to direct the refrigerant fluid and the gas to be liquefied and/or subcooled through the first subcooler (70); and, when the gas to be liquefied and/or subcooled is the second gas, the refrigeration device (10) is configured to provide the refrigerant fluid at the second low temperature, and the subcooling arrangement (50) is configured to direct the refrigerant fluid and the gas to be liquefied and/or subcooled through the second subcooler (72).

2. The liquefaction and subcooling system of claim 1, comprising a multi-stream heat exchanger (100), wherein a heat exchanger of the refrigeration device (10) is formed, and wherein the first and second subcoolers (70, 72) are formed by separate conduits.

3. The liquefaction and subcooling system of claim 1, wherein the subcooling arrangement (50) comprises a combined subcooler (202) formed by a heat exchanger, wherein the first subcooler and the second subcooler are formed by separate conduits.

4. The liquefaction and subcooling system of claim 1, wherein the first and second subcoolers (70, 72) are formed by separate heat exchangers (302, 304).

5. The liquefaction and subcooling system according to any one of the preceding claims, wherein the first and/or second subcooler (70, 72) is formed by a plate-fin heat exchanger.

6. The liquefaction and subcooling system according to any one of the preceding claims, wherein the refrigerant fluid is selected from helium, nitrogen, methane, ethane, neon, or a combination thereof.

7. The liquefaction and subcooling system of any one of the preceding claims, wherein the difference between the first low temperature and the second low temperature is in the range of 30 ℃ to 100 ℃, more preferably in the range of 40 ℃ to 80 ℃, most preferably in the range of 50 ℃ to 70 ℃.

8. The liquefaction and subcooling system of any one of the preceding claims, wherein the first cryogenic temperature is in the range of-120 ℃ to-85 ℃, preferably-115 ℃, and the second cryogenic temperature is in the range of-183 ℃ to-155 ℃, preferably-178 ℃.

9. The liquefaction and subcooling system of any one of the preceding claims, wherein the first gas is ethane and the second gas is natural gas.

10. A boil-off gas management system (400) comprising a liquefaction and subcooling system (412) according to any one of claims 1 to 9, wherein the liquefaction and subcooling system is arranged to reliquefy a boil-off gas.

11. A method for liquefying and subcooling different first and second gases having different saturation temperatures at a given pressure, the method comprising

Providing a refrigeration device (10) operable to alternately provide a refrigerant fluid at a first cryogenic temperature and a second cryogenic temperature corresponding to different liquefaction temperatures of the first and second gases; and the number of the first and second electrodes,

operating the refrigeration device (10) to provide the refrigerant fluid at the first cryogenic temperature when the gas to be liquefied and/or subcooled is the first gas, and directing the gas to be liquefied and/or subcooled through a first subcooler (70) to exchange heat with the refrigerant fluid; and the number of the first and second electrodes,

operating the refrigeration device (10) to provide the refrigerant fluid at the second cryogenic temperature when the gas to be liquefied and/or subcooled is the second gas, and directing the gas to be liquefied and/or subcooled through a second subcooler (72) to exchange heat with the refrigerant fluid.