KR20160149399A - Vessel Including Storage Tanks - Google Patents

Vessel Including Storage Tanks Download PDF

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Publication number
KR20160149399A
KR20160149399A KR1020150086292A KR20150086292A KR20160149399A KR 20160149399 A KR20160149399 A KR 20160149399A KR 1020150086292 A KR1020150086292 A KR 1020150086292A KR 20150086292 A KR20150086292 A KR 20150086292A KR 20160149399 A KR20160149399 A KR 20160149399A
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KR
South Korea
Prior art keywords
natural gas
compressor
heat exchanger
inflator
fluid
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KR1020150086292A
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Korean (ko)
Inventor
윤상득
Original Assignee
대우조선해양 주식회사
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Priority to KR1020150086292A priority Critical patent/KR20160149399A/en
Publication of KR20160149399A publication Critical patent/KR20160149399A/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C5/00—Methods or apparatus for filling containers with liquefied, solidified, or compressed gases under pressures
    • F17C5/02—Methods or apparatus for filling containers with liquefied, solidified, or compressed gases under pressures for filling with liquefied gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B25/00—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby
    • B63B25/02—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods
    • B63B25/08—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid
    • B63B25/12—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid closed
    • B63B25/16—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid closed heat-insulated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/0002—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the fluid to be liquefied
    • F25J1/0022—Hydrocarbons, e.g. natural gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2221/00—Handled fluid, in particular type of fluid
    • F17C2221/03—Mixtures
    • F17C2221/032—Hydrocarbons
    • F17C2221/033—Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
    • F17C2227/01—Propulsion of the fluid
    • F17C2227/0128—Propulsion of the fluid with pumps or compressors
    • F17C2227/0171—Arrangement
    • F17C2227/0185—Arrangement comprising several pumps or compressors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
    • F17C2227/03—Heat exchange with the fluid
    • F17C2227/0337—Heat exchange with the fluid by cooling
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
    • F17C2227/03—Heat exchange with the fluid
    • F17C2227/0337—Heat exchange with the fluid by cooling
    • F17C2227/0358—Heat exchange with the fluid by cooling by expansion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2265/00—Effects achieved by gas storage or gas handling
    • F17C2265/01—Purifying the fluid
    • F17C2265/015—Purifying the fluid by separating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2270/00—Applications
    • F17C2270/01—Applications for fluid transport or storage
    • F17C2270/0102—Applications for fluid transport or storage on or in the water
    • F17C2270/0105—Ships

Abstract

A ship comprising a storage tank is disclosed.
The ship including the storage tank includes: a first compressor for compressing natural gas supplied from outside the system; A first cooler for cooling the natural gas compressed by the first compressor; A first inflator for inflating a portion of the natural gas that has passed through the first compressor and the first cooler; A second inflator for further inflating the fluid that has passed through the first inflator; A first heat exchanger for self-heat-exchanging natural gas to cool the natural gas; Expansion means for expanding the fluid that has passed through the first heat exchanger; A second compressor for compressing a fluid used as a refrigerant in the first heat exchanger; And a second cooler for cooling the fluid passing through the second compressor, wherein the first heat exchanger is branched after passing through the first compressor and the first cooler, and the first expander and the second expander The fluid expanded by at least one of the expanders is used as a refrigerant to cool the other part of the natural gas branched after passing through the first compressor and the first cooler.

Figure P1020150086292

Description

[0001] VESSEL Including Storage Tanks [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a ship including a storage tank, and more particularly, to a ship including a storage tank, To a storage tank, comprising a storage tank.

Recently, the consumption of liquefied gas such as Liquefied Natural Gas (LNG) and Liquefied Petroleum Gas (LPG) has been rapidly increasing worldwide. The liquefied gas obtained by liquefying the gas at a low temperature has an advantage of being able to increase the storage and transport efficiency because the volume becomes very small as compared with the gas. In addition, liquefied natural gas (LNG) and other liquefied gases can be used as eco-friendly fuels that can reduce or eliminate air pollutants during the liquefaction process.

Liquefied natural gas is a colorless transparent liquid obtained by cooling methane-based natural gas to about -162 ° C and liquefying it, and has a volume of about 1/600 of that of natural gas. Therefore, it is very efficient when liquefied natural gas is transported to liquefied natural gas.

However, since the liquefaction temperature of natural gas is a cryogenic temperature of about -162 ° C at normal pressure, liquefied natural gas is easily vaporized due to temperature change sensitivity. However, since the external heat is continuously transferred to the storage tank, the liquefied natural gas is naturally vaporized continuously in the storage tank during the transportation of the liquefied natural gas, and the evaporation gas (BOG; Boil -Off Gas) occurs. This also applies to other low temperature liquefied gases such as ethane.

Evaporation gas is a kind of loss, and reducing the evaporation gas is an important issue in transportation efficiency. Further, when the evaporation gas accumulates in the storage tank, the internal pressure of the tank may rise excessively, and there is a risk that the tank may be damaged. Accordingly, various methods for treating the evaporative gas generated in the storage tank have been studied. Recently, a method of re-liquefying the evaporative gas and returning it to a storage tank, a method of using evaporative gas as an energy source of a fuel consuming place, Method and the like are used.

It is an object of the present invention to provide a vessel including a storage tank that liquefies natural gas using liquefied natural gas itself as a refrigerant and returns it to a storage tank without using a separate refrigerant system.

According to an aspect of the present invention, there is provided a gas turbine comprising: a first compressor for compressing natural gas supplied from outside the system; A first cooler for cooling the natural gas compressed by the first compressor; A first inflator for inflating a portion of the natural gas that has passed through the first compressor and the first cooler; A second inflator for further inflating the fluid that has passed through the first inflator; A first heat exchanger for self-heat-exchanging natural gas to cool the natural gas; Expansion means for expanding the fluid that has passed through the first heat exchanger; A second compressor for compressing a fluid used as a refrigerant in the first heat exchanger; And a second cooler for cooling the fluid passing through the second compressor, wherein the first heat exchanger is branched after passing through the first compressor and the first cooler, and the first expander and the second expander Characterized in that the fluid expanded by at least one of the expanders serves as a refrigerant to cool the other part of the natural gas that has branched off after passing through the first compressor and the first cooler do.

The natural gas passing through the first compressor may be in a supercritical fluid state.

The expansion means may be an expansion valve or an expander.

Wherein the vessel including the storage tank further comprises: a third compressor for additionally compressing the natural gas compressed by the first compressor; A third cooler for lowering the temperature of the natural gas passing through the third compressor; A first gas-liquid separator provided at a downstream end of the expansion means for separating liquefied natural gas from natural gas in a gaseous state; And a first valve for controlling a flow rate and a pressure of the natural gas separated by the first gas-liquid separator, wherein the first compressor, the first compressor, the third compressor, The natural gas that has passed through can be cooled in the first heat exchanger and the gaseous natural gas separated by the first gas-liquid separator flows from the second inflator to the first heat exchanger in a line Can be sent.

The natural gas passing through the first compressor and the third compressor may be in a supercritical fluid state.

The natural gas supplied to the system may be split into two, then one stream may be sent to the first compressor, and the other stream may be sent to the first expander.

The natural gas having passed through the first compressor and the first cooler may be branched into two, then one flow may be sent to the third compressor, and another flow may be sent to the first inflator.

The natural gas having passed through the first compressor, the first cooler, the third compressor, and the third cooler may be branched into two, then one flow may be sent to the first heat exchanger, Lt; / RTI >

The first valve may adjust the pressure of the natural gas separated by the first gas-liquid separator to be equal to the pressure of the fluid sent from the second inflator to the first heat exchanger.

Wherein the first valve is configured such that a sum of a flow rate of a fluid sent from the second inflator to the first heat exchanger and a flow rate of natural gas to be sent to the first heat exchanger from the first gas- The flow rate of the natural gas can be adjusted.

Wherein the vessel including the storage tank further comprises a second gas-liquid separator for separating the partially liquefied natural gas and the natural gas remaining in the gaseous state through the first inflator; And a second valve for controlling a flow rate and a pressure of the liquefied natural gas separated by the second gas-liquid separator and sent to the first heat exchanger, wherein the gas- Natural gas may be sent to the second expander, wherein the first heat exchanger is a liquefied natural gas separated by the second gas-liquid separator and then passed through the second valve; And a fluid which has been separated by the second gas-liquid separator and has passed through the second inflator, can be used as a refrigerant.

Wherein the second valve controls the flow rate of the fluid passing through the second inflator and sent to the first heat exchanger and the sum of the liquefied natural gas separated from the second gas-liquid separator and sent to the first heat exchanger, The flow rate of the liquefied natural gas can be controlled so as not to exceed the capacity of the flue gas.

The second valve may expand the liquefied natural gas separated from the second gas-liquid separator.

The ship including the storage tank includes a second heat exchanger for self-heat-exchanging liquefied natural gas having passed through the first inflator; A fourth compressor for compressing the fluid passing through the second heat exchanger; And a fourth cooler for lowering the temperature of the fluid passing through the fourth compressor, wherein the second heat exchanger uses the fluid sent from the first inflator as a refrigerant, and after being sent from the first inflator, The fluid passing through the second heat exchanger, the fourth compressor, and the fourth cooler may be cooled and then sent to the second gas-liquid separator.

According to another aspect of the present invention, there is provided a compressor for compressing natural gas, comprising: a first compressor for compressing natural gas supplied from the outside; a first expander for expanding the fluid passing through the first compressor; A second compressor for further expanding the fluid, a first heat exchanger using the fluid expanded by the second expander as a refrigerant, and a second compressor for compressing the fluid used as the refrigerant in the first heat exchanger , Refrigerant systems; And an expansion device for expanding the fluid that has passed through the first heat exchanger and the first heat exchanger for cooling the natural gas that has passed through the first compressor by using the first compressor, the refrigerant supplied by the refrigerant system, Wherein the refrigerant system is an open loop. ≪ RTI ID = 0.0 > A < / RTI >

The liquefaction system may further include a first gas-liquid separator for separating liquefied natural gas that has passed through the first heat exchanger and the expansion means and natural gas remaining in a gaseous state, The liquefied natural gas separated by the first gas-liquid separator can be sent to the storage tank, and the natural gas separated by the first gas-liquid separator can be sent to the refrigerant system.

The refrigerant system may further include a second gas-liquid separator for separating liquefied natural gas liquefied by the first inflator and natural gas remaining in a gaseous state, and the liquefied natural gas separated by the second gas- Can be sent to the first heat exchanger and used as a refrigerant, and the natural gas separated by the second gas-liquid separator can be sent to the second inflator.

Wherein the refrigerant system includes a second heat exchanger for liquefying the fluid expanded by the first inflator and sending it to the second gas-liquid separator; And a third compressor for compressing the fluid passing through the second heat exchanger, wherein the second heat exchanger uses the fluid that has passed through the first inflator as a refrigerant, passes through the first inflator The fluid passing through the second heat exchanger and the third compressor can be cooled.

According to another aspect of the present invention, there is provided a method for compressing and cooling natural gas supplied from outside the system, comprising the steps of: 1) branching the compressed and cooled natural gas into two flows; 2) (Hereinafter referred to as 'a flow'), the natural gas (hereinafter, referred to as 'b flow') of one of the two branched flows 3) the b-flow is expanded and partially liquefied after being heat-exchanged with the a-stream as refrigerant, and 4) the a-flow is heat-exchanged with the b-stream and then compressed and cooled , A method is provided.

In the step 3), the b-flow may be separated from the liquid phase and the gaseous phase after part or all of liquefaction, and the liquefied natural gas separated from the b-flow may be sent to the storage tank, The natural gas may again be heat exchanged as a refrigerant to cool the b stream.

In the step (b), the a-flow can be separated from the liquid phase and the gaseous phase after being branched and expanded, and the liquefied natural gas separated from the a-flow can be heat-exchanged as a refrigerant for cooling the b-flow, The natural gas separated from the a stream may be heat exchanged as a refrigerant that is further expanded and then cools the b stream.

In the step 2), the a-flow may be heat-exchanged as a refrigerant after branched and expanded (hereinafter, the a-flow after heat exchange is referred to as a "c-flow"), the c-flow is compressed and cooled, The refrigerant can be heat-exchanged as a refrigerant that cools the b stream after being self-heat-exchanged with the a-stream.

According to the present invention, since a separate refrigerant system is not used, there is an advantage that the system is simple and convenient to operate.

In addition, a system using the liquefied natural gas itself as a refrigerant can be roughly divided into a closed loop and an open loop. Since the present invention uses an open loop, The control of the refrigerant system is simple and the components of the system are simple.

1 is a schematic view showing a ship including a storage tank according to a first preferred embodiment of the present invention.
2 is a schematic view showing a ship including a storage tank according to a second preferred embodiment of the present invention.
3 is a schematic view showing a ship including a storage tank according to a third preferred embodiment of the present invention.
4 is a schematic view showing a ship including a storage tank according to a fourth preferred embodiment of the present invention.
5 is a graph schematically illustrating the phase change of methane with temperature and pressure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The vessel including the storage tank of the present invention can be applied to various applications on ships equipped with liquefied natural gas storage tanks and onshore. In addition, the following examples can be modified in various forms, and the scope of the present invention is not limited to the following examples.

1 is a schematic view showing a ship including a storage tank according to a first preferred embodiment of the present invention.

The term "fluid" in this embodiment means a natural gas, a liquefied natural gas, or a mixture of natural gas and liquefied natural gas. The natural gas, which was gaseous when supplied to the system, passes through each device and can become gas, liquid or vapor-liquid mixed depending on the pressure and temperature. Hereinafter, the same applies.

Referring to FIG. 1, a vessel including the storage tank of this embodiment includes a first compressor 110 for compressing natural gas supplied to the system; A first cooler 210 for cooling the natural gas compressed by the first compressor 110; A first inflator (512) for inflating a portion of the natural gas having passed through the first compressor (110) and the first cooler (210); A second inflator (522) for further inflating the fluid that has passed through the first inflator (512); A first heat exchanger (310) for cooling the natural gas using the expanded fluid as a refrigerant; Expansion means (600) for expanding the fluid having passed through the first heat exchanger (310); A second compressor 511 for compressing the fluid used as the refrigerant in the first heat exchanger 310; And a second cooler (230) for cooling the fluid passing through the second compressor (511).

The first compressor (110) of this embodiment compresses the natural gas supplied from outside the system. The ship including the storage tank of the present embodiment is for delivering natural gas having passed through the first compressor 110 to the storage tank through the first heat exchanger 310 and the expansion means 600, Compressing by the first compressor 110 before being sent to the first heat exchanger 310 is to increase liquefaction efficiency in the first heat exchanger 310. A more detailed explanation is as follows.

5 is a graph schematically illustrating the phase change of methane with temperature and pressure. Referring to FIG. 5, methane enters a supercritical fluid state at a temperature of approximately -80 DEG C or higher and a pressure of approximately 50 bar or more. That is, in the case of methane, the critical point is about -80 ° C, 50 bar. The supercritical fluid state is a third state different from the liquid state or gas state.

However, in the course of re-liquefaction of the evaporated gas, the natural gas may contain a nitrogen component. Depending on the content of nitrogen, the critical point may be changed.

On the other hand, if the temperature is lower than the critical point at a pressure higher than the critical point, the state of the supercritical fluid may be similar to that of the supercritical fluid, which is different from the general liquid state. , Hereinafter referred to as "high pressure liquid state ".

5, the natural gas in the relatively low pressure state (X in FIG. 5) is passed through the first heat exchanger 310 and the expansion means 600 to lower the temperature and the pressure, (X 'of FIG. 5). However, it can be seen that even if the temperature and pressure are lowered equally after increasing the pressure of the gas (Y in FIG. 5) have. That is, it is known that the liquefaction efficiency increases as the natural gas pressure is increased before the natural gas passes through the first heat exchanger 310, and the liquefaction can be theoretically 100% if the pressure can be sufficiently increased (Z in FIG. 5) (Z 'in Fig. 5).

Accordingly, the ship including the storage tank of the present embodiment includes the first compressor 110 to increase the pressure of the natural gas before sending the natural gas to the first heat exchanger 310, Thereby increasing the liquefaction efficiency. The first compressor 110 of the present embodiment preferably compresses the natural gas at a pressure of about 50 bar or more so that the natural gas can be in a supercritical state.

The first cooler 210 of the present embodiment lowers the temperature of the natural gas that has passed through the first compressor 110 and has increased temperature as well as pressure. The first cooler 210 can cool natural gas by, for example, heat-exchanging natural gas with fresh water at about room temperature.

The first inflator 512 of the present embodiment inflates a portion of the natural gas that has passed through the first compressor 110 and the first cooler 210 and sends it to the second inflator 522.

The second inflator 522 of the present embodiment further inflates the fluid expanded by the first inflator 512 after passing through the first compressor 110 and the first cooler 210 and then flows into the first heat exchanger 310 ).

The first heat exchanger 310 of the present embodiment is a device in which a part of the natural gas that has passed through the first compressor 110 and the first cooler 210 passes through the first inflator 512 and the second inflator 522 Cooled by self-heat exchange with fluid. Self-cooling means that a part of the natural gas is cooled without using a separate refrigerant, and the natural gas itself is used as a refrigerant for cooling the natural gas.

The ship including the storage tank of the present embodiment liquefies part of the natural gas that has passed through the first compressor 110 and the first cooler 210 by the first heat exchanger 310 and the expansion means 600 The fluid to be used as the refrigerant in the first heat exchanger 310 is supplied to the first and second inflators 512 and 522 at a temperature sufficiently low to liquefy the natural gas by the first inflator 512 and the second inflator 522, Lt; / RTI >

The expansion means (600) of this embodiment lowers the pressure of the fluid whose temperature has been lowered by the heat exchange in the first heat exchanger (310). The natural gas is partly or entirely liquefied while passing through the first heat exchanger 310 and the expansion means 600 and the liquefied natural gas is mixed with the natural gas remaining in the gaseous state in a gas-liquid mixed state Liquefied natural gas is sent to a storage tank. The expansion means 600 may be an expansion valve or an expander.

The second compressor 511 of the present embodiment compresses the fluid used as the refrigerant in the first heat exchanger 310 after passing through the first inflator 512 and the second inflator 522.

The second cooler 230 of this embodiment is installed at the downstream end of the second compressor 511 to lower the temperature of the fluid passing through the second compressor 511 as well as the pressure. The fluid having passed through the second compressor 511 and the second cooler 230 is sent to the first compressor 110 together with the natural gas supplied to the system. The second cooler 230 of this embodiment can cool the fluid by, for example, heat-exchanging fluid with fresh water at about room temperature.

The flow of the fluid in this embodiment will be described as follows.

Natural gas supplied from outside the system is compressed by the first compressor 110, cooled by the first cooler 210, and then branched into two flows. One stream is directed to the first heat exchanger 310 and the other stream is directed to the first expander 512 where the first expander 512) is used as the refrigerant.

The natural gas that has passed through the first compressor 110 and the first cooler 210 and then sent to the first inflator 512 is expanded by the first inflator 512 and then sent to the second inflator 522. The fluid once again expanded by the second expander 522 is sent to the first heat exchanger 310.

After passing through the first inflator 512 and the second inflator 522, the cooled fluid is heat-exchanged with the natural gas in the first heat exchanger 310, and then the cold heat is partially or entirely vaporized by the natural gas, The entirely vaporized fluid is sent to the second compressor 511 and compressed.

The fluid compressed by the second compressor 511 is cooled by the second cooler 230 and then sent back to the first compressor 110 together with the natural gas supplied from the outside of the system so that the above- .

That is, in this embodiment, the fluid used as the refrigerant is compressed by the second compressor 511 as much as the pressure is lowered by the first inflator 512 and the second inflator 522, and the natural gas is supplied to the system And then sent to the first compressor (110).

The natural gas that has passed through the first compressor 110 and the first cooler 210 and then sent to the first heat exchanger 310 is subjected to heat exchange with the fluid inflated by the first and second inflators 512, And then expanded by the expansion means 600. The fluid that has passed through the first heat exchanger 310 and the expansion means 600 and partially or fully liquefied is sent to the storage tank.

2 is a schematic view showing a ship including a storage tank according to a second preferred embodiment of the present invention.

The ship including the storage tank of the second embodiment shown in Fig. 2 is different from the ship including the storage tank of the first embodiment shown in Fig. 1 in that the third compressor 120, the third cooler 240, 1 gas-liquid separator 410 and a first valve 710. Hereinafter, differences will be mainly described. A detailed description of the same components as those of the ship including the storage tank of the above-described first embodiment will be omitted.

2, the vessel including the storage tank of the present embodiment includes a first compressor 110, a first cooler 210, a first inflator 512, a second inflator 522 A first heat exchanger 310, an expansion means 600, a second compressor 511, and a second cooler 230.

However, the ship including the storage tank of this embodiment is different from the first embodiment in that the third compressor 120 additionally compresses the natural gas firstly compressed by the first compressor 110; A third cooler 240 for lowering the temperature of the natural gas passing through the third compressor 120; A first gas-liquid separator (410) installed downstream of the expansion means (600) for separating liquefied natural gas from natural gas in a gaseous state; And a first valve (710) for regulating the flow rate and pressure of the gaseous natural gas separated by the first gas-liquid separator (410).

As in the first embodiment, the first compressor 110 of this embodiment compresses the natural gas supplied from the outside of the system, and the first cooler 210 of this embodiment, similarly to the first embodiment, (110) to lower the temperature of the natural gas as well as the pressure.

The third compressor 120 of this embodiment further compresses some of the natural gas that has passed through the first compressor 110 and the first cooler 210. As described above, it is advantageous in terms of liquefaction efficiency to increase the pressure of the natural gas before the natural gas passes through the first heat exchanger 310. It is not sufficient to compress the natural gas to a sufficient pressure with only the first compressor 110 In this case, as in the present embodiment, it may further include a compressor. In this embodiment, the natural gas is compressed in two stages. However, a compression process may be added as needed.

In this embodiment, the natural gas is branched between the first compressor 210 and the third compressor 120 before the second compression process after the first compression process. However, The natural gas may be branched before the first compression process, that is, at the front end of the first compressor 110, or after the second compression process, that is, at the rear end of the third cooler 240.

The reason for dividing the natural gas between the first compressor 210 and the third compressor 120 in the present embodiment is that the natural gas, which is branched and sent to the first expander 512 to be used as the refrigerant, Is expanded by the first expansion unit 512 and the second expansion unit 522 and then sent to the first heat exchanger 310. It is inefficient to compress the natural gas to be subjected to the expansion process through the two-stage compression process. Therefore, the branch point can be determined in consideration of the natural gas to be used as the refrigerant and the required pressure of the natural gas to be liquefied.

The natural gas compressed by the first compressor 110 and the third compressor 120 of the present embodiment preferably has a pressure of about 50 bar or more so as to be in a supercritical state.

The third cooler 240 of the present embodiment lowers the temperature of the natural gas that passes through the third compressor 120 and increases not only in pressure but also in temperature. For example, by exchanging heat between fresh water and natural gas at a room temperature, Natural gas can be cooled.

The first inflator 512 of the present embodiment inflates a part of the natural gas that has passed through the first compressor 110 and the first cooler 210 and sends it to the second inflator 522 as in the first embodiment The second inflator 522 of the present embodiment is configured to further expand the fluid inflated by the first inflator 512 after passing through the first compressor 110 and the first cooler 210 as in the first embodiment And then sent to the first heat exchanger 310.

The first heat exchanger 310 of the present embodiment is a system in which the natural gas that has passed through the first compressor 110, the first cooler 210, the third compressor 120 and the third cooler 240 is introduced into the first inflator 512 and the second inflator 522 to cool it.

As in the first embodiment, the expansion means 600 of the present embodiment lowers the pressure of the fluid whose temperature has been lowered by the heat exchange in the first heat exchanger 310, and the natural gas is introduced into the first heat exchanger 310 and the expansion means 600, the liquid is partly or entirely liquefied. The expansion means 600 may be an expansion valve or an expander.

The first gas-liquid separator 410 of the present embodiment is disposed at the downstream end of the expansion means 600 and passes through the first heat exchanger 310 and the expansion means 600 and remains in a gaseous state with a part of liquefied natural gas Separates the natural gas and delivers the liquefied natural gas to the storage tank and the natural gas passes over the line from the second inflator 522 to the first heat exchanger 310,

The first valve 710 of the present embodiment is installed on a line for sending natural gas from the first gas-liquid separator 410 to the second inflator 522 and the first heat exchanger 310, . The first valve 710 is connected to the first gas-liquid separator 710 in consideration of the flow rate of the fluid passing through the second inflator 522 to the first heat exchanger 310 and the capacity of the first heat exchanger 310, The amount of natural gas sent from the first inflator 422 to the first inflator 522 and the first heat exchanger 310 and from the second inflator 522 to the first heat exchanger 310, The pressure of the natural gas is adjusted so that the pressure of the natural gas sent from the first gas-liquid separator 410 to the second inflator 522 and the first heat exchanger 310 becomes similar.

The second compressor 511 of the present embodiment compresses the fluid used as the refrigerant in the first heat exchanger 310 after passing through the first inflator 512 and the second inflator 522 as in the first embodiment .

The second cooler 230 of the present embodiment is disposed at the downstream end of the second compressor 511 to lower the temperature of the fluid passing through the second compressor 511 as well as the pressure and the temperature, as in the first embodiment. The fluid having passed through the second compressor 511 and the second cooler 230 is sent to the first compressor 110 together with the natural gas supplied to the system.

The flow of the fluid in this embodiment will be described as follows.

Natural gas supplied from outside the system is firstly compressed by the first compressor 110, cooled by the first cooler 210, and then branched into two flows, as in the first embodiment. One of them is different from the first embodiment in that it is secondarily compressed by the third compressor 120, cooled by the third cooler 240, and then sent to the first heat exchanger 310, The flow is directed to the first inflator 512, as in the first embodiment.

Natural gas that has passed through the first compressor 110 and the first cooler 210 and then sent to the first inflator 512 is expanded by the first inflator 512 and then supplied to the second inflator 512, Lt; / RTI > The fluid once again expanded by the second expander 522 is sent to the first heat exchanger 310 as in the first embodiment.

Like the first embodiment, the cooled fluid passing through the first inflator 512 and the second inflator 522 is heat-exchanged with the natural gas in the first heat exchanger 310 and some or all of the fluid is vaporized, Or the entirely vaporized fluid is sent to the second compression section 511 and compressed.

The fluid compressed by the second compression unit 511 is cooled by the second cooler 230 and then sent to the first compressor 110 together with the natural gas supplied from the outside of the system similarly to the first embodiment , The above-mentioned series of steps is again performed.

The natural gas that has passed through the first compressor 110 and the first cooler 210 and then branched after passing through the third compressor 120 and the third cooler 240 is sent to the first heat exchanger 310, Exchanged with the fluid inflated by the first inflator 512 and the second inflator 522, and then expanded by the expansion means 600.

Unlike the first embodiment, the fluid which has passed through the first heat exchanger 310 and the expansion means 600 and partially or completely liquefied is not sent directly to the storage tank in a gas-liquid mixed state, The liquid phase and the gas phase are separated by the separator 410. The liquefied natural gas separated by the first gas-liquid separator 410 is sent to the storage tank, and the natural gas separated by the first gas-liquid separator 410 passes through the first valve 710, 522 to the first heat exchanger 310 and used again as a refrigerant.

3 is a schematic view showing a ship including a storage tank according to a third preferred embodiment of the present invention.

The vessel including the storage tank of the third embodiment shown in Fig. 3 is different from the vessel including the storage tank of the second embodiment shown in Fig. 2 in that the second gas-liquid separator 420 and the second valve 720 There is a difference therebetween. In the following, the difference will be mainly described. A detailed description of the same components as those of the ship including the storage tank of the second embodiment described above will be omitted.

Referring to FIG. 3, the ship including the storage tank of the present embodiment includes a first compressor 110, a first cooler 210, a third compressor 120, a third cooler 240 A first compressor 412, a first compressor 411, a second compressor 412, a first compressor 412, a first compressor 412, a first compressor 412, a first compressor 412, ) And a second cooler (230).

However, unlike the second embodiment, the vessel including the storage tank of the present embodiment is installed between the first inflator 512 and the second inflator 522, passes through the first inflator 512, A second gas-liquid separator (420) for separating the liquefied natural gas and the natural gas remaining in the gaseous state; And a second valve (720) for regulating the flow rate and pressure of the liquefied natural gas separated by the second gas-liquid separator (420) and sent to the first heat exchanger (310).

As in the second embodiment, the first compressor 110 of this embodiment compresses the natural gas supplied from the outside of the system, and the first cooler 210 of this embodiment, similarly to the second embodiment, (110) to lower the temperature of the natural gas as well as the pressure.

The third compressor 120 of this embodiment further compresses some of the natural gas that has passed through the first compressor 110 and the first cooler 210, as in the second embodiment. The natural gas compressed by the first compressor 110 and the third compressor 120 of the present embodiment preferably has a pressure of about 50 bar or more so as to be in a supercritical state.

As in the second embodiment, the third cooler 240 of the present embodiment lowers the temperature of the natural gas that has passed through the third compressor 120 and has increased in temperature as well as pressure.

The first inflator 512 of the present embodiment expands a part of the natural gas that has passed through the first compressor 110 and the first cooler 210, as in the second embodiment. However, unlike the second embodiment, the first inflator 512 of the present embodiment inflates a part of the natural gas that has passed through the first compressor 110 and the first cooler 210, 522, but first sends it to the second gas-liquid separator 420.

The second gas-liquid separator 420 of this embodiment separates the liquefied natural gas and the remaining natural gas from the liquefied natural gas passing through the first inflator 512, and the liquefied natural gas is introduced into the first heat exchanger 310, To be used as a refrigerant, and the natural gas is sent to the second inflator 522 to be further inflated by the second inflator 522.

The vessel including the storage tank of this embodiment allows the liquefied natural gas separated by the second gas-liquid separator 420 including the second gas-liquid separator 420 to be used as the refrigerant in the first heat exchanger 310 The liquefaction efficiency in the first heat exchanger 310 can be higher than in the first and second embodiments.

The second valve 720 of the present embodiment is installed on a line for sending the liquefied natural gas separated by the second gas-liquid separator 420 to the first heat exchanger 310 to control the flow rate and pressure of the liquefied natural gas do. In other words, the second valve 720 is connected to the second gas-liquid separator 720 in consideration of the flow rate of the fluid passing through the second inflator 522 to the first heat exchanger 310 and the capacity of the first heat exchanger 310, The amount of liquefied natural gas sent from the first heat exchanger 310 to the first heat exchanger 310 is controlled and the temperature of the liquefied natural gas used as the refrigerant in the first heat exchanger 310 is further lowered, Liquid separator 420 to further expand the liquefied natural gas to be sent to the first heat exchanger 310 so as to increase the liquefaction efficiency in the first gas-liquid separator 420.

The second inflator 522 of the present embodiment inflates the natural gas separated by the second gas-liquid separator 420 and sends it to the first heat exchanger 310.

The first heat exchanger 310 of the present embodiment is similar to the second embodiment in that the first and second heat exchangers 310 and 310 are disposed in the first and second compressors 110 and 210 and the third and fourth compressors 120 and 240, Gas is cooled by self-heat exchange with the fluid that has passed through the first inflator 512 and the second inflator 522.

However, unlike the second embodiment, the first heat exchanger 310 of this embodiment uses not only the fluid that has passed both the first inflator 512 and the second inflator 522 as a refrigerant, Liquid separator 420 after being passed through the second gas-liquid separator 512 and used as a refrigerant.

As in the second embodiment, the expansion means 600 of the present embodiment lowers the pressure of the fluid whose temperature has been lowered by the heat exchange in the first heat exchanger 310, and the natural gas is introduced into the first heat exchanger 310 and the expansion means 600, the liquid is partly or entirely liquefied. The expansion means 600 may be an expansion valve or an expander.

The first gas-liquid separator 410 of the present embodiment is provided at the downstream end of the expansion means 600 and passes through the first heat exchanger 310 and the expansion means 600 to partially liquefy liquefied natural gas Separates the natural gas remaining in the gaseous state with the liquefied natural gas, and sends the natural gas onto the line from which the fluid is sent from the second inflator 522 to the first heat exchanger 310.

The first valve 710 of the present embodiment is installed on a line for sending natural gas between the second inflator 522 and the first heat exchanger 310 from the first gas-liquid separator 410 as in the second embodiment , And the flow rate and pressure of the natural gas.

The second compressor 511 of the present embodiment compresses the fluid used as the refrigerant in the first heat exchanger 310, as in the second embodiment.

Like the second embodiment, the second cooler 230 of the present embodiment is disposed at the downstream end of the second compressor 511 to lower the temperature of the fluid passing through the second compressor 511 as well as the pressure. The fluid having passed through the second compressor 511 and the second cooler 230 is sent to the first compressor 110 together with the natural gas supplied to the system.

The flow of the fluid in this embodiment will be described as follows.

Natural gas supplied from outside the system is firstly compressed by the first compressor 110, cooled by the first cooler 210, and then branched into two flows, as in the second embodiment. One of the flows is secondarily compressed by the third compressor 120, cooled by the third cooler 240, and then sent to the first heat exchanger 310, as in the second embodiment, Is sent to the first inflator 512, as in the second embodiment.

Unlike the second embodiment, the natural gas that has passed through the first compressor 110 and the first cooler 210 and then sent to the first inflator 512 is expanded by the first inflator 512, Liquid separator 420 is not sent directly to the expander 522 but to the second gas-liquid separator 420 first. The fluid that has passed through the first expander 512 and then sent to the second gas-liquid separator 420 is separated from the liquefied natural gas and the natural gas.

The liquefied natural gas separated by the second gas-liquid separator 420 is sent to the first heat exchanger 310 after passing through the second valve 720 and used as a refrigerant. The liquefied natural gas used as the refrigerant in the first heat exchanger 310 after passing through the second valve 720 is partially or wholly vaporized and sent to the first heat exchanger 310 from the second inflator 522 The fluid passes through the first heat exchanger 310 and then is sent on the line to be sent to the second compressor 511.

The natural gas separated by the second gas-liquid separator (420) is sent to the second expander (522). The fluid once expanded by the second inflator 522 after being separated by the second gas-liquid separator 420 is sent to the first heat exchanger 310 and used as a refrigerant.

The fluid separated by the second gas-liquid separator 420, passed through the second expander 522, and then sent to the first heat exchanger 310 is supplied to the first heat exchanger 310 through the first heat exchanger 310, Fluid partially or fully vaporized and partially or fully vaporized after the heat exchange is transferred from the second gas-liquid separator 420 to the first heat exchanger 310 and integrated with the fluid used as the refrigerant, 511).

The fluid compressed by the second compressor 511 is cooled by the second cooler 230 and then sent back to the first compressor 110 together with the natural gas supplied from the outside of the system , The above-mentioned series of steps is again performed.

The natural gas that has passed through the first compressor 110 and the first cooler 210 and then branched after passing through the third compressor 120 and the third cooler 240 is sent to the first heat exchanger 310, A liquefied natural gas that is expanded by the first expander 512 and then separated by the second gas-liquid separator 420; And a fluid that is expanded by the first expander 512 and separated by the second gas-liquid separator 420 and then once expanded by the second expander 522, and then expanded by the expansion means 600, do.

The fluid having passed through the first heat exchanger 310 and the expansion means 600 and partially or completely liquefied is separated from the liquid phase and the gas phase by the first gas-liquid separator 410, as in the second embodiment. The liquefied natural gas separated by the first gas-liquid separator 410 is sent to the storage tank in the same manner as the second embodiment, and the natural gas separated by the first gas-liquid separator 410 is sent to the storage tank , Passes through the first valve (710), is sent to the first heat exchanger (310) together with the fluid passing through the second inflator (522), and is used again as the refrigerant.

4 is a schematic view showing a ship including a storage tank according to a fourth preferred embodiment of the present invention.

The ship including the storage tank of the fourth embodiment shown in FIG. 4 is different from the ship including the storage tank of the third embodiment shown in FIG. 3 in that the second heat exchanger 320, the fourth compressor 130, There is a difference in that it further includes the fourth cooler 250, and the difference will be mainly described below. A detailed description of the same components as those of the ship including the storage tank of the third embodiment described above will be omitted.

Referring to FIG. 4, the ship including the storage tank of the present embodiment includes a first compressor 110, a first cooler 210, a third compressor 120, a third cooler 240 A second gas-liquid separator 420, a second valve 720, a second inflator 522, a first heat exchanger 310, an expansion means 600, a first gas-liquid separator (not shown) 410, a first valve 710, a second compressor 511, and a second cooler 230.

However, unlike the third embodiment, the vessel including the storage tank of the present embodiment is installed between the first inflator 512 and the second gas-liquid separator 420, and the natural gas which has passed through the first inflator 512 A second heat exchanger (320) for self-heat-exchanging gas to liquefy the gas; A fourth compressor 130 for compressing the fluid that has passed through the second heat exchanger 320 first; And a fourth cooler (250) for lowering the temperature of the fluid passing through the fourth compressor (130).

 The first compressor (110) of this embodiment compresses the natural gas supplied from the outside of the system in the same manner as the third embodiment, and the first cooler (210) of the present embodiment is similar to the third embodiment, (110) to lower the temperature of the natural gas as well as the pressure.

The third compressor 120 of this embodiment further compresses some of the natural gas that has passed through the first compressor 110 and the first cooler 210 as in the third embodiment. The natural gas compressed by the first compressor 110 and the third compressor 120 of the present embodiment preferably has a pressure of about 50 bar or more so as to be in a supercritical state.

As in the third embodiment, the third cooler 240 of the present embodiment lowers the temperature of the natural gas that has passed through the third compressor 120 and has increased in temperature as well as pressure.

The first inflator 512 of the present embodiment expands a part of the natural gas that has passed through the first compressor 110 and the first cooler 210 as in the third embodiment. However, unlike the second embodiment, the first inflator 512 of the present embodiment inflates a part of the natural gas that has passed through the first compressor 110 and the first cooler 210, To the second heat exchanger (320), not to the second heat exchanger (420).

The second heat exchanger 320 of this embodiment is configured to pass the fluid that has passed through the first expander 512 and the fourth compressor 130 and the fourth cooler 250 after passing through the second heat exchanger 320 Heat exchange one fluid. That is, the second heat exchanger 320 uses the fluid that has passed through the second inflator 522 as the refrigerant, passes through the fourth compressor 130 and the fourth cooler 250, and liquefies the fluid having a high pressure.

As shown in FIG. 5, when the pressure is low, even if the temperature of the natural gas is lowered, it may not be liquefied (X in FIG. 5) (Y in Fig. 5).

Accordingly, the fluid that has passed through the first inflator 512 and the second heat exchanger 320 is compressed by the fourth compressor 130 and then sent to the second heat exchanger 320 so that the first inflator 512, The fluid whose pressure is increased by the fourth compressor 130 is cooled and a part of the fluid can be liquefied.

When the liquefied natural gas is not generated in an amount sufficient for use as a refrigerant in the first heat exchanger 310 only by the expansion by the first expander 512 and the second expander 522, The heat exchanger 320 and the fourth compressor 130 to increase the liquefaction amount of the natural gas used as the refrigerant.

The fourth compressor 130 of the present embodiment increases the pressure of the fluid heat-exchanged as a first refrigerant in the second heat exchanger 320 after passing through the first inflator 512.

The fourth cooler 250 of the present embodiment lowers the temperature of the fluid passing through the fourth compressor 130 as well as the pressure. The fourth cooler 250 can cool the fluid by, for example, heat-exchanging the fluid with fresh water at about room temperature.

The second gas-liquid separator (420) of this embodiment separates the partially liquefied natural gas and the natural gas remaining in the gaseous state through the second heat exchanger (320) and, as in the third embodiment, To the first heat exchanger 310 so that it can be used as a refrigerant and the natural gas is sent to the second inflator 522 to be further inflated by the second inflator 522.

The second valve 720 of this embodiment is installed on a line for sending the liquefied natural gas separated by the second gas-liquid separator 420 to the first heat exchanger 310 as in the third embodiment, Adjust the flow and pressure of the gas.

The second inflator 522 of the present embodiment inflates the natural gas separated by the second gas-liquid separator 420 and sends it to the first heat exchanger 310 as in the third embodiment.

The first heat exchanger 310 of the present embodiment is configured such that the first compressor 110, the first cooler 210, the third compressor 120, and the third cooler 240, The gas is cooled by self-heat exchange with the refrigerant.

The first heat exchanger 310 of the present embodiment is different from the third embodiment in that the first inflator 512, the second heat exchanger 320, the fourth compressor 130 and the fourth cooler 250, The liquefied natural gas liquefied in the second heat exchanger 320 and separated by the second gas-liquid separator 420; And after passing through the first expander 512, the second heat exchanger 320, the fourth compressor 130 and the fourth cooler 250, they can not be liquefied in the second heat exchanger 320 and the second gas-liquid separator 420 And then passed through the second inflator 522, as a refrigerant.

As in the third embodiment, the expansion means 600 of the present embodiment lowers the pressure of the fluid whose temperature has been lowered by heat exchange in the first heat exchanger 310, and the natural gas is introduced into the first heat exchanger 310 and the expansion means 600, the liquid is partly or entirely liquefied. The expansion means 600 may be an expansion valve or an expander.

The first gas-liquid separator 410 of the present embodiment is disposed at the downstream end of the expansion means 600 and passes through the first heat exchanger 310 and the expansion means 600 and is partly liquefied natural Separates the natural gas remaining in the gaseous state with the liquefied natural gas, and sends the natural gas onto the line from which the fluid is sent from the second inflator 522 to the first heat exchanger 310.

The first valve 710 of the present embodiment is installed on a line for sending natural gas between the second inflator 522 and the first heat exchanger 310 from the first gas-liquid separator 410 as in the third embodiment , And the flow rate and pressure of the natural gas.

The second compressor 511 of the present embodiment compresses the fluid used as the refrigerant in the first heat exchanger 310 as in the third embodiment.

The second cooler 230 of the present embodiment is installed at the rear end of the second compressor 511 of the first inflator 512 and passes through the second compressor 511 and not only the pressure but also the temperature Lowering the temperature of the raised fluid. The fluid having passed through the second compressor 511 and the second cooler 230 is sent to the first compressor 110 together with the natural gas supplied to the system.

The flow of the fluid in this embodiment will be described as follows.

Natural gas supplied from outside the system is firstly compressed by the first compressor 110, cooled by the first cooler 210, and then branched into two flows, as in the third embodiment. One of the flows is compressed by the third compressor 120, cooled by the third cooler 240, and then sent to the first heat exchanger 310, as in the third embodiment, Is sent to the first inflator 512, as in the third embodiment.

Unlike the third embodiment, the natural gas, which has passed through the first compressor 110 and the first cooler 210 and then sent to the first inflator 512, is expanded by the first inflator 512, 2 gas-liquid separator 420, but is sent to the second heat exchanger 320 first. The fluid that has passed through the first expander 512 and then sent to the second heat exchanger 320 is heat exchanged in the second heat exchanger 320 as the first refrigerant and then flows into the fourth compressor 130 and the fourth cooler 250 And then again exchanges heat with the fluid sent from the first inflator 512 to the second heat exchanger 320. The fluid that has undergone the second heat exchange in the second heat exchanger (320) after passing through the fourth compressor (130) and the fourth cooler (250) is sent to the second gas-liquid separator (420).

The liquid sent to the second gas-liquid separator 420 is separated from the liquefied natural gas and the natural gas and separated by the second gas-liquid separator 420 in the same manner as in the third embodiment, Likewise, after passing through the second valve 720, it is sent to the first heat exchanger 310 to be used as a refrigerant, and the natural gas separated by the second gas-liquid separator 420, The refrigerant is sent to the expander 522, expanded once again, and then sent to the first heat exchanger 310 to be used as a refrigerant.

The liquefied natural gas that has been separated by the second gas-liquid separator 420 and passed through the second valve 720 and the first heat exchanger 310 is partially or completely vaporized as in the third embodiment, The fluid sent from the expander 522 to the first heat exchanger 310 is sent to the second compressor 511 after passing through the first heat exchanger 310.

The fluid separated by the second gas-liquid separator 420, passed through the second expander 522, and then sent to the first heat exchanger 310 is supplied to the first heat exchanger 310 through the first heat exchanger 310, A part or all of the vaporized and partially vaporized fluid is sent from the second gas-liquid separator 420 to the first heat exchanger 310 to be separated from the fluid used as the refrigerant, And is sent to the second compressor 511.

The fluid compressed by the second compressor 511 is cooled by the second cooler 230 and sent to the first compressor 110 together with the natural gas supplied from the outside of the system similarly to the third embodiment, The above-mentioned series of steps is repeated again.

The natural gas that has passed through the first compressor 110 and the first cooler 210 and then branched and has passed through the third compressor 120 and the third cooler 240 is subjected to the first heat exchange Liquid natural gas separated by the second gas-liquid separator 420; And a second inflator (522), and then expanded by the expansion means (600).

The liquid, which has passed through the first heat exchanger 310 and the expansion means 600 and partially or completely liquefied, is separated from the liquid phase and the gas phase by the first gas-liquid separator 410 as in the third embodiment. The liquefied natural gas separated by the first gas-liquid separator 410 is sent to the storage tank similarly to the third embodiment, and the natural gas separated by the first gas-liquid separator 410, , Passes through the first valve (710), is sent to the first heat exchanger (310) together with the fluid passing through the second inflator (522), and is used again as the refrigerant.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. It is.

110, 120, 130, 511: compressors 210, 230, 240, 250:
310, 320: heat exchanger 410, 420: gas-liquid separator
512, 522: inflator 600: expansion means
710, 720: valve

Claims (22)

A first compressor for compressing natural gas supplied from outside the system;
A first cooler for cooling the natural gas compressed by the first compressor;
A first inflator for inflating a portion of the natural gas that has passed through the first compressor and the first cooler;
A second inflator for further inflating the fluid that has passed through the first inflator;
A first heat exchanger for self-heat-exchanging natural gas to cool the natural gas;
Expansion means for expanding the fluid that has passed through the first heat exchanger;
A second compressor for compressing a fluid used as a refrigerant in the first heat exchanger; And
And a second cooler for cooling the fluid passing through the second compressor,
Wherein the first heat exchanger is branched after passing through the first compressor and the first cooler and uses a fluid expanded by at least one of the first inflator and the second inflator as a refrigerant, Characterized in that it is cooled after passing through the first cooler to cool some of the branched natural gas. The method according to claim 1,
Wherein the natural gas having passed through the first compressor is in a supercritical fluid state. The method according to claim 1,
Wherein the expansion means is an expansion valve or inflator. The method according to claim 1,
A third compressor for additionally compressing the natural gas compressed by the first compressor;
A third cooler for lowering the temperature of the natural gas passing through the third compressor;
A first gas-liquid separator provided at a downstream end of the expansion means for separating liquefied natural gas from natural gas in a gaseous state; And
Further comprising a first valve for controlling the flow rate and pressure of the natural gas separated by the first gas-liquid separator,
The natural gas having passed through the first compressor, the first cooler, the third compressor, and the third cooler is cooled in the first heat exchanger,
Wherein the gaseous natural gas separated by the first gas-liquid separator is sent on a line through which fluid is sent from the second inflator to the first heat exchanger. The method of claim 4,
Wherein the natural gas having passed through the first compressor and the third compressor is in a supercritical fluid state. The method of claim 4,
Wherein the natural gas supplied to the system is diverted into two, then one stream is sent to the first compressor, and the other stream is sent to the first expander. The method of claim 4,
Wherein the natural gas having passed through the first compressor and the first cooler is branched into two and then one flow is sent to the third compressor and the other flow is sent to the first inflator. The method of claim 4,
The natural gas that has passed through the first compressor, the first cooler, the third compressor, and the third cooler is branched into two, then one stream is sent to the first heat exchanger, the other stream is sent to the first expander A vessel containing a storage tank to be sent. The method of claim 4,
Wherein the first valve regulates the pressure of the natural gas separated by the first gas-liquid separator to the same pressure as the fluid sent from the second inflator to the first heat exchanger. The method of claim 4,
Wherein the first valve is configured such that the sum of the flow rate of the fluid sent from the second inflator to the first heat exchanger and the flow rate of the natural gas to be sent from the first gas-liquid separator to the first heat exchanger is smaller than the capacity of the first heat exchanger Of the natural gas so as not to exceed the flow rate of the natural gas. The method of claim 4,
A second gas-liquid separator for separating the partially liquefied natural gas and the natural gas remaining in the gaseous state through the first inflator; And
And a second valve for controlling the flow rate and pressure of the liquefied natural gas separated by the second gas-liquid separator and sent to the first heat exchanger,
The gaseous natural gas separated by the second gas-liquid separator is sent to the second inflator,
Wherein the first heat exchanger comprises: liquefied natural gas separated by the second gas-liquid separator and then passed through the second valve; And a fluid that has been separated by the second gas-liquid separator and then passed through the second inflator as a refrigerant. The method of claim 11,
Wherein the second valve controls the flow rate of the fluid passing through the second inflator and sent to the first heat exchanger and the sum of the liquefied natural gas separated from the second gas-liquid separator and sent to the first heat exchanger, Wherein the volume of the liquefied natural gas is controlled so as not to exceed the capacity of the storage tank. The method of claim 11,
And the second valve includes a storage tank for expanding the liquefied natural gas separated from the second gas-liquid separator. The method of claim 11,
A second heat exchanger for self-heat-exchanging liquefied natural gas having passed through the first inflator;
A fourth compressor for compressing the fluid passing through the second heat exchanger; And
And a fourth cooler for lowering the temperature of the fluid passing through the fourth compressor,
Wherein the second heat exchanger uses the fluid sent from the first inflator as a refrigerant to cool the fluid that has passed through the second heat exchanger, the fourth compressor, and the fourth cooler after being sent from the first inflator, 2 A vessel containing a storage tank to be sent to a gas - liquid separator. A first compressor for compressing natural gas supplied from the outside, a first inflator for expanding the fluid passing through the first compressor, a second inflator for further expanding the fluid expanded by the first inflator, a second inflator for expanding the fluid inflated by the second inflator, A refrigerant system comprising a first heat exchanger using the fluid expanded by the first heat exchanger as a refrigerant and a second compressor for compressing the fluid used as refrigerant in the first heat exchanger; And
The first compressor, the first heat exchanger for cooling the natural gas that has passed through the first compressor using the refrigerant supplied by the refrigerant system, and the expansion means for expanding the fluid that has passed through the first heat exchanger A liquefaction system;
/ RTI >
Wherein the refrigerant system is an open loop. 16. The method of claim 15,
In the liquefaction system,
Further comprising a first gas-liquid separator for separating liquefied natural gas that has passed through the first heat exchanger and the expansion means and natural gas remaining in a gaseous state,
The liquefied natural gas separated by the first gas-liquid separator is sent to the storage tank,
Wherein the natural gas separated by the first gas-liquid separator is sent to the refrigerant system. 16. The method of claim 15,
In the refrigerant system,
Further comprising a second gas-liquid separator for separating liquefied natural gas liquefied by said first inflator and natural gas remaining in a gaseous state,
The liquefied natural gas separated by the second gas-liquid separator is sent to the first heat exchanger and used as a refrigerant,
Wherein the natural gas separated by the second gas-liquid separator is sent to the second inflator. 18. The method of claim 17,
In the refrigerant system,
A second heat exchanger for liquefying the fluid expanded by the first expander and sending it to the second gas-liquid separator; And
And a third compressor for compressing the fluid passing through the second heat exchanger,
Wherein the second heat exchanger includes a storage tank that uses the fluid that has passed through the first inflator as a refrigerant to cool the fluid that has passed through the first inflator and passed through the second heat exchanger and the third compressor Ship. Compresses and cools natural gas supplied from outside the system,
1) branching said compressed and cooled natural gas into two streams,
2) a natural gas (hereinafter referred to as "a flow") of one of the two branched flows is flowed (hereinafter referred to as "a flow" , referred to as " b flow "),
3) The b-flow is a heat exchanging process using the a-stream as a refrigerant, and then expanded to liquefy a part or the whole,
4) the a-stream is heat-exchanged with b-stream and then compressed and cooled. The method of claim 19,
In the step (3), the b-flow is a step of separating the liquid phase and the gaseous phase after part or all of liquefaction,
The liquefied natural gas separated from the stream b is sent to a storage tank,
Wherein the natural gas separated from the b-flow is again heat-exchanged as a refrigerant for cooling the b-flow. The method of claim 19,
In the 2) step, the a-flow is separated from the liquid phase and the gaseous phase after branched and expanded,
The liquefied natural gas separated from the a-flow is heat-exchanged as a refrigerant for cooling the b-flow,
Wherein the natural gas separated from the a stream is further heat exchanged as a refrigerant that cools the b stream after being expanded. The method of claim 19,
In the step 2), the a-flow is heat-exchanged as a refrigerant after branched and expanded (hereinafter, the a-flow after heat exchange is referred to as a "c-flow"
Wherein the c stream is compressed and cooled to self-heat exchange with the a stream and then heat exchanged as a refrigerant to cool the b stream.
KR1020150086292A 2015-06-18 2015-06-18 Vessel Including Storage Tanks KR20160149399A (en)

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Application Number Priority Date Filing Date Title
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Publication number Priority date Publication date Assignee Title
KR20190028894A (en) * 2017-09-11 2019-03-20 주식회사 동화엔텍 Natural Gas Liquefaction System Using Expender with Methane Refrigerant

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20190028894A (en) * 2017-09-11 2019-03-20 주식회사 동화엔텍 Natural Gas Liquefaction System Using Expender with Methane Refrigerant

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