KR101629200B1 - Vessel - Google Patents

Abstract

Disclosed is a vessel having a storage tank for storing liquefied gas therein. The vessel comprises: a boil-off gas heat exchanger which cools the boil-off gas discharged from the storage tank; a compressor which compresses a part of the boil-off gas discharged from the storage tank; a first spare compressor which compresses the other part of the boil-off gas discharged from the storage tank; a second spare compressor which compresses the residual part of the boil-off gas discharged from the storage tank; a refrigerant heat exchanger which additionally cools the boil-off gas cooled by the boil-off gas heat exchanger; a refrigerant decompression device which expands the boil-off gas cooled by the refrigerant heat exchanger and resends the expanded boil-off gas to the refrigerant heat exchanger; and a first decompression device which expands the boil-off gas cooled by the boil-off gas heat exchanger and the refrigerant heat exchanger. Thus, the present invention improves the re-liquefaction performance of the boil-off gas.

Description

Ship {Vessel}

The present invention relates to a ship, and more particularly, to a ship including a system for re-liquefying remaining evaporative gas used as fuel of an engine among evaporative gases generated in a storage tank.

In recent years, consumption of liquefied gas such as Liquefied Natural Gas (LNG) 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, including liquefied natural gas, can be removed as an eco-friendly fuel with less air pollutant emissions during combustion because air pollutants can be removed or reduced 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 it has a volume of about 1/600 of that of natural gas. Therefore, when the natural gas is liquefied and transported, it can be transported very efficiently.

However, since the liquefaction temperature of natural gas is a cryogenic temperature of -162 ° C at normal pressure, liquefied natural gas is sensitive to temperature changes and is easily evaporated. As a result, the storage tank storing the liquefied natural gas is subjected to heat insulation, but the external heat is continuously transferred to the storage tank. Therefore, in the transportation of liquefied natural gas, the liquefied natural gas is naturally vaporized continuously in the storage tank, -Off Gas, BOG) occurs. This also applies to other low temperature liquefied gases such as ethane.

Evaporation gas is a kind of loss and is an important issue in transport 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 evaporated gas and returning it to the storage tank for treating the evaporated gas, a method of returning the evaporated gas to the storage tank And a method of using it as an energy source of a consuming place.

As a method for re-liquefying the evaporation gas, there is a method of re-liquefying the evaporation gas by heat exchange with the refrigerant by providing a refrigeration cycle using a separate refrigerant, and a method of re-liquefying the evaporation gas by using the evaporation gas itself as a refrigerant . Particularly, the system adopting the latter method is called a Partial Re-liquefaction System (PRS).

On the other hand, among the engines used in ships, there are gas fuel engines such as DFDE and ME-GI engines which can use natural gas as fuel.

The DFDE adopts the Otto Cycle, which consists of four strokes, and injects natural gas with a relatively low pressure of about 6.5 bar into the combustion air inlet, compressing the piston as it rises.

The ME-GI engine consists of two strokes and employs a diesel cycle in which high pressure natural gas at around 300 bar is injected directly into the combustion chamber at the top of the piston. In recent years, there is a growing interest in ME-GI engines with better fuel efficiency and propulsion efficiency.

An object of the present invention is to provide a ship including a system capable of exhibiting enhanced evaporative gas re-liquefaction performance as compared with a conventional partial liquefaction system.

According to an aspect of the present invention, there is provided a ship including a storage tank for storing a liquefied gas, the ship including a storage tank disposed downstream of the storage tank, An evaporating gas heat exchanger for exchanging heat with the evaporating gas (hereinafter, referred to as 'first fluid') to cool the evaporating gas; A compressor installed downstream of the evaporating gas heat exchanger for compressing a part of the evaporated gas discharged from the storage tank; A first extra compressor installed in parallel with the compressor downstream of the evaporative gas heat exchanger to compress another portion of the evaporative gas discharged from the storage tank; A second redundant compressor installed downstream of the evaporative gas heat exchanger in parallel with the compressor and the first redundant compressor to compress a remaining portion of the evaporative gas discharged from the storage tank; A refrigerant heat exchanger for additionally cooling the first fluid cooled by the evaporation gas heat exchanger; (Hereinafter referred to as " second fluid ") that is sent to the refrigerant heat exchanger (hereinafter, referred to as a " second fluid ") to expand the second fluid cooled by the refrigerant heat exchanger to the refrigerant heat exchanger ; And a first decompression device for expanding the first fluid cooled by the evaporation gas heat exchanger and the refrigerant heat exchanger, wherein the refrigerant heat exchanger uses the evaporation gas that has passed through the refrigerant decompression device as a refrigerant, The first fluid is cooled by heat exchange with both the first fluid and the second fluid, the first fluid comprising: evaporative gas compressed by the compressor; An evaporation gas compressed by said first extra compressor; A flow combining the evaporated gas compressed by the compressor and the evaporated gas compressed by the first extra compressor; And a flow of the evaporated gas compressed by the compressor, the evaporated gas compressed by the first extra compressor, and the evaporated gas compressed by the second extra compressor; And the second fluid comprises: an evaporation gas compressed by the first extra compressor; An evaporation gas compressed by said second extra compressor; A flow combining the evaporation gas compressed by the first extra compressor and the evaporation gas compressed by the second extra compressor; And a flow of the evaporated gas compressed by the compressor, the evaporated gas compressed by the first extra compressor, and the evaporated gas compressed by the second extra compressor; The ship is provided.

The evaporated gas used as the refrigerant of the refrigerant heat exchanger after passing through the refrigerant depressurization device may be merged with the evaporated gas that has passed through the evaporative gas heat exchanger after being discharged from the storage tank.

The evaporated gas used as the refrigerant in the refrigerant heat exchanger after being compressed by the first extra compressor is again sent to the first extra compressor to be supplied to the first extra compressor, the refrigerant heat exchanger, the refrigerant decompressor, The refrigerant cycle of the closed loop that circulates the refrigerant can be formed.

The evaporated gas used as the refrigerant of the refrigerant heat exchanger after being compressed by the second extra compressor is again sent to the second extra compressor to be supplied to the second extra compressor, the refrigerant heat exchanger, the refrigerant decompressor, The refrigerant cycle of the closed loop that circulates the refrigerant can be formed.

The evaporated gas compressed by the first extra compressor and the evaporated gas compressed by the second extra compressor are combined and supplied to the refrigerant heat exchanger, and the evaporated gas supplied to the refrigerant heat exchanger is re- A coolant cycle of a closed loop may be formed by passing through the refrigerant heat exchanger and branching back to two flows to the first extra compressor or the second extra compressor.

According to another aspect of the present invention, there is provided an evaporative gas processing system for a ship including a storage tank for storing a liquefied gas, wherein a part of the evaporative gas discharged from the storage tank is compressed by a compressor A first supply line for sending to a fuel consumer; A second supply line which is branched from the first supply line and compresses another part of the evaporated gas discharged from the storage tank by a first extra compressor; A third supply line that is branched from the second supply line and compresses the remaining part of the evaporated gas discharged from the storage tank by a second extra compressor; A return line branched from the first supply line and passing the compressed evaporated gas through an evaporating gas heat exchanger, a refrigerant heat exchanger, and a first pressure reducing device to re- And a recirculation line passing through the refrigerant heat exchanger and the refrigerant decompression device to return the cooled evaporated gas to the refrigerant heat exchanger for use as a refrigerant and then to join with the evaporated gas discharged from the storage tank, The gas heat exchanger uses the evaporation gas discharged from the storage tank as a refrigerant and cools the evaporation gas supplied along the return line by heat exchange. The refrigerant heat exchanger uses the evaporation gas that has passed through the refrigerant decompression apparatus as a refrigerant An evaporation gas supplied along the recycle line; And an evaporation gas supplied along the return line are cooled by heat exchange with each other.

The recirculation line upstream of the refrigerant pressure reducing device and the refrigerant heat exchanger is connected to the third supply line downstream of the second extra compressor; And the second supply line downstream of the first redundant compressor are connected in series and then connected to a first supply line downstream of the compressor, A first valve installed upstream of the compressor; A second valve installed downstream of the compressor on the first supply line; A third valve installed upstream of the first extra compressor on the second supply line; A fourth valve installed downstream of the first extra compressor on the second supply line; A sixth valve installed on the recirculation line between the first supply line and the second supply line; A ninth valve installed on the recirculation line for sending the evaporation gas from the refrigerant heat exchanger to the first supply line; A tenth valve installed upstream of the second extra compressor on the third supply line; An eleventh valve installed downstream of said second extra compressor on said third supply line; And a twelfth valve installed on the recycle line between the second supply line and the third supply line, wherein the sixth valve and the twelfth valve are opened and closed, Evaporated gas; An evaporation gas compressed by said first extra compressor; And the evaporation gas compressed by the second extra compressor can be joined or separated.

An evaporation gas treatment system for the ship comprises a first additional line connecting between the recycle line and the third supply line; A second additional line connecting the first additional line and the second supply line; A thirteenth valve installed on the first additional line; And a fourteenth valve installed on the second additional line.

One side of the first additional line may be connected to the recirculation line for sending the evaporation gas that has passed through the refrigerant decompressor and the refrigerant heat exchanger to the first supply line and the other side may be connected to the recirculation line through the tenth valve and the second extra One side of the second additional line may be connected to the first additional line upstream of the thirteenth valve and the other side may be connected to the third supply line between the third valve and the first extra line, And to the second supply line between the compressors.

Wherein when the ship is traveling at a high speed, only one of the compressor, the first extra compressor, and the second extra compressor can be used, and when the ship is traveling at a low speed, the compressor, the first extra compressor, And the second extra compressor may be used. When the ship is docked, both the compressor, the first extra compressor, and the second extra compressor may be used.

Wherein the first valve, the second valve, the third valve, the fourth valve, the sixth valve, the tenth valve, the eleventh valve, the thirteenth valve, and the fifteenth valve are opened, 9 valve, the twelfth valve, and the fourteenth valve are closed, and when the evaporation gas is supplied to the second extra compressor, the tenth valve is closed, and the evaporation gas is supplied to the second extra compressor, A refrigerant cycle of a closed loop circulating the eleventh valve, the refrigerant heat exchanger, the refrigerant decompressor, the refrigerant heat exchanger, and the thirteenth valve may be formed.

Wherein the first valve, the second valve, the third valve, the fourth valve, the twelfth valve, the fourteenth valve, and the fifteenth valve are opened and the sixth valve, the ninth valve, 10 valve, the eleventh valve, and the thirteenth valve drive the system in a closed state, and when the evaporation gas is supplied to the first extra compressor, the third valve is closed, and the evaporation gas is supplied to the first extra compressor, A refrigerant cycle of a closed loop circulating the fourth valve, the twelfth valve, the refrigerant heat exchanger, the refrigerant decompressor, the refrigerant heat exchanger, and the fourteenth valve may be formed.

Wherein the first valve, the second valve, the fourth valve, the ninth valve, the eleventh valve, the twelfth valve, the thirteenth valve, the fourteenth valve, and the fifteenth valve are opened, The third valve, the sixth valve, and the tenth valve are closed, and when the evaporation gas is supplied to the first extra compressor and the second extra compressor, the ninth valve is closed, and the first The evaporation gas compressed by the extra compressor and the evaporation gas passing through the second extra compressor are combined and supplied to the refrigerant heat exchanger, and the evaporation gas supplied to the refrigerant heat exchanger is passed through the refrigerant decompressor, again through the refrigerant heat exchanger And then branched again into two flows to be sent to the first extra compressor and the second extra compressor, respectively, to form a closed loop refrigerant cycle.

Wherein the first valve, the second valve, the third valve, the fourth valve, the sixth valve, the ninth valve, the tenth valve, the eleventh valve, the twelfth valve, The thirteenth valve and the fourteenth valve are closed and the evaporation gas compressed by the compressor, the evaporation gas compressed by the first extra compressor, and the evaporation gas compressed by the second extra compressor are merged And can be operated.

Wherein the first valve, the second valve, the third valve, the fourth valve, the ninth valve, the tenth valve, the eleventh valve, the twelfth valve, and the fifteenth valve are opened, The sixth valve, the thirteenth valve and the fourteenth valve are closed so that the evaporated gas compressed by the first extra compressor and the evaporated gas compressed by the second extra compressor are combined and sent to the refrigerant heat exchanger, Some of the evaporated gas compressed by the evaporating gas heat exchanger can be sent to the fuel consumer and the other part can be sent to the evaporating gas heat exchanger.

Wherein the first valve, the second valve, the third valve, the fourth valve, the sixth valve, the ninth valve, the tenth valve, the eleventh valve, and the fifteenth valve are opened, 12 valve, the thirteenth valve, and the fourteenth valve are closed, the evaporated gas compressed by the second extra compressor is sent to the refrigerant heat exchanger, and the evaporated gas compressed by the compressor and the first extra compressor The compressed evaporated gas may be combined, some of it may be sent to the fuel consumer, and some of it may be sent to the evaporative gas heat exchanger.

In accordance with another aspect of the present invention, there is provided a method for controlling a flow of a refrigerant in a liquefied gas storage tank by branching the evaporated gas discharged from a liquefied gas storage tank into three, At least one of the evaporation gas compressed by the compressor, the evaporation gas compressed by the compressor, the evaporation gas compressed by the first extra compressor, and the evaporation gas compressed by the second extra compressor is sent to the fuel consumer (Hereinafter, referred to as 'recirculated evaporative gas'), and the returned evaporative gas is discharged from the storage tank (hereinafter, referred to as 'recycled evaporative gas'). Exchanged with the recirculated evaporated gas and then further cooled with the recirculated evaporated gas and the recirculated evaporated gas is cooled and expanded, And a method, which heat exchanger is provided.

The compressor downstream line and the first extra compressor downstream line are connected so that the evaporated gas compressed by the compressor can be merged with the evaporated gas compressed by the first extra compressor.

The first extra compressor downstream line and the second extra compressor downstream line are connected so that the evaporated gas compressed by the first extra compressor can be merged with the evaporated gas compressed by the second extra compressor.

An evaporation gas compressed by the compressor to which the compressor downstream line, the first extra compressor downstream line, and the second extra compressor downstream line are connected; An evaporation gas compressed by said first extra compressor; And the evaporation gas compressed by the second extra compressor can be joined.

Compared with the existing partial liquefaction system (PRS), the present invention reduces the pressure of the evaporation gas after an additional cooling process by the refrigerant heat exchanger, so that the liquefaction efficiency and the liquefaction amount can be increased. In particular, it is economical to re-cure most or all of the remaining evaporated gas without using a refrigeration cycle using a separate refrigerant.

Further, according to the present invention, it is possible to flexibly control the refrigerant flow rate and the cooling / heating supply according to the engine load depending on the discharge amount of the evaporation gas and the operating speed of the ship.

According to the embodiment of the present invention, since the re-liquefaction efficiency and the amount of liquefaction are increased by using the existing extra compressor, it contributes to securing the space inside the ship and further reduces the cost for installing the compressor . Particularly, not only the evaporation gas compressed by the extra compressor but also the evaporation gas compressed by the compressor can be used as the refrigerant in the refrigerant heat exchanger, so that the flow rate of the evaporation gas used as the refrigerant in the refrigerant heat exchanger can be increased, The liquefaction efficiency and the liquefaction amount can be further increased.

In addition, since the present invention includes two or more redundant compressors, it is possible to use compressors having a small capacity, which is economical and can sufficiently prevent a failure of a compressor or an extra compressor. Further, Detailed and flexible system operation is possible.

1 is a schematic view showing a conventional partial remelting system.
FIG. 2 is a schematic view showing a system for processing an evaporative gas of a ship according to a first embodiment of the present invention.
FIG. 3 is a schematic view showing a system for processing an evaporative gas of a ship according to a second embodiment of the present invention.
4 is a schematic view showing a system for processing an evaporative gas of a ship according to a third embodiment of the present invention.
5 is a schematic view showing a system for processing an evaporative gas of a ship according to a fourth embodiment of the present invention.
6 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 ship of the present invention can be applied to various applications such as a ship equipped with an engine using natural gas as fuel and a ship including a liquefied gas storage tank. 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.

Systems for the treatment of the evaporative gas to be described below of the present invention include all types of ships and marine structures, such as liquefied natural gas carriers, liquefied ethane gas carriers, and the like, with storage tanks capable of storing low temperature liquid cargo or liquefied gas, It can be applied to marine structures such as LNG FPSO and LNG FSRU as well as ships such as LNG RV. However, in the following embodiments, liquefied natural gas, which is a typical low temperature liquid cargo, will be described as an example for convenience of explanation.

The fluid in each line of the present invention may be in any one of a liquid state, a gas-liquid mixed state, a gas state, and a supercritical fluid state, depending on operating conditions of the system.

1 is a schematic view showing a conventional partial remelting system.

Referring to FIG. 1, in the conventional partial remanufacturing system, the evaporated gas generated and discharged from the storage tank storing the liquid cargo is conveyed along the pipe and compressed by the evaporated gas compression unit 10.

The storage tank (T) has sealing and thermal barrier to store liquefied gas such as liquefied natural gas at a cryogenic temperature, but it can not completely block the heat transmitted from the outside, and the evaporation of the liquefied gas is continuous And the tank internal pressure can be raised. In order to prevent excessive increase of the tank pressure due to the evaporated gas and to maintain an appropriate level of internal pressure, the evaporated gas inside the storage tank is discharged to the evaporated gas compression unit 10 Supply.

When the evaporated gas discharged from the storage tank and compressed by the evaporation gas compression unit 10 is referred to as a first stream, the first stream of the compressed evaporative gas is divided into the second stream and the third stream, and the second stream is liquefied To the storage tank T, and the third stream may be configured to be supplied to a gas fuel consuming destination such as a propulsion engine or a power generation engine onboard the ship. In this case, in the evaporation gas compression unit 10, the evaporation gas can be compressed to the supply pressure of the fuel consumption source, and the second stream can be branched through all or a part of the evaporation gas compression unit if necessary. All of the evaporated gas compressed in the third stream may be supplied according to the amount of fuel required by the fuel consumption point, or the entire amount of the compressed evaporated gas may be returned to the storage tank. Gas fuel consumption may include a high pressure gas injection engine (e.g., ME-GI engine developed by MDT) and a low pressure gas injection engine (e.g., Wartsila X-DF engine ), DF Generator, gas turbine, DFDE, and the like.

At this time, the heat exchanger 20 is installed to liquefy the second stream of the compressed evaporated gas, and the evaporated gas generated in the storage tank is used as a cold heat source of the compressed evaporated gas. The compressed evaporated gas, that is, the second stream, which has risen in temperature during the compression process in the evaporated gas compressor, is cooled while passing through the heat exchanger 20, and the evaporated gas generated in the storage tank and introduced into the heat exchanger 20 is heated And is supplied to the evaporation gas compression unit 10.

Since the flow rate of the evaporated gas before compression is greater than the flow rate of the second stream, the second stream of compressed evaporated gas may be at least partially liquefied by receiving cold heat from the evaporated gas before being compressed. Thus, in the heat exchanger, the low-temperature evaporation gas immediately after being discharged from the storage tank is heat-exchanged with the high-pressure evaporation gas compressed by the evaporation gas compression unit to liquefy the high-pressure evaporation gas.

The evaporated gas of the second stream passing through the heat exchanger 20 is further cooled while being decompressed while passing through the expansion means 30 such as an expansion valve or an expander and is supplied to the gas-liquid separator 40. The liquid component, that is, the liquefied natural gas, is returned to the storage tank, and the gaseous component, that is, the evaporation gas is discharged from the storage tank to be separated from the heat exchanger 20 and the evaporation gas Is utilized as a cold / hot supply source that joins the evaporation gas flow to the evaporation gas flow supplied to the compression section (10) or is supplied to the heat exchanger (20) again to heat the evaporation gas in the high pressure state compressed by the evaporation gas compression section . Of course, it may be sent to a gas combustion unit (GCU) or the like, or it may be consumed by sending it to a gas consumption source (including a gas engine). Further expansion means (50) for further depressurizing the gas separated in the gas-liquid separator before joining the evaporative gas stream may be further provided.

FIG. 2 is a schematic view showing a system for processing an evaporative gas of a ship according to a first embodiment of the present invention.

Referring to FIG. 2, the system of the present embodiment is characterized in that a refrigerant circulation unit 300a which is supplied with boil off gas generated from low-temperature liquid refrigerant stored in a storage tank and circulates the evaporated gas to the refrigerant is formed .

And a refrigerant supply line (CSLa) for supplying evaporation gas from the storage tank to the refrigerant circulation part (300a). The valve (400a) is provided in the refrigerant supply line, and a sufficient amount of evaporation gas The refrigerant supply line CSLa is cut off and the refrigerant circulation unit 300a is operated as a closed loop.

As in the above-described basic embodiment, in the first modified embodiment, a compressor 100a for compressing evaporative gas generated from low-temperature liquid cargo in the storage tank T is provided. The evaporated gas generated in the storage tank is introduced into the compressor 100a along the evaporation gas supply line BLa.

The storage tank (T) of the present embodiment is made of an independent type tank in which the load of the liquid cargo is not directly applied to the heat insulating layer, or a membrane type tank in which the load of the cargo is directly applied to the heat insulating layer . In the case of an independent tank type tank, it is also possible to use it as a pressure vessel designed to withstand a pressure of 2 barg or more.

In the meantime, although only the line for re-liquefaction of the evaporation gas is shown in the embodiments, the evaporation gas compressed in the compressor can be supplied as fuel to the fuel demanding site including the propulsion engine and the power generation engine of the ship or the sea structure , And there may be no evaporative gas that is re-liquefied when the fuel consumption can consume the entire amount of evaporated gas. When the consumption of the gaseous fuel is low or absent, such as when the ship is anchored, the entire amount of the evaporated gas may be supplied to the re-liquefaction line RLa.

The compressed evaporated gas is supplied to the evaporation gas heat exchanger 200a along the evaporation gas re-liquefaction line RLa. The evaporation gas heat exchanger 200a is connected to the evaporation gas re-liquefaction line RLa and the evaporation gas supply line BLa, So as to heat exchange the evaporated gas to be introduced into the compressor 100a and the compressed evaporated gas through at least a part of the compressor. The evaporated gas whose temperature has increased in the compression process is cooled through heat exchange with the low temperature evaporated gas which is generated in the storage tank and is to be introduced into the compressor 100a.

A refrigerant heat exchanger 500a is provided downstream of the evaporation gas heat exchanger 200a and the evaporated gas heat-exchanged in the evaporation gas heat exchanger after the compression is further cooled through heat exchange with the evaporation gas circulating in the refrigerant circulation unit 300a .

The refrigerant circulation unit 300a includes a refrigerant compressor 310a for compressing the evaporation gas supplied from the storage tank, a cooler 320a for cooling the evaporation gas compressed in the refrigerant compressor, And further includes a refrigerant decompression device 330a for further cooling. The refrigerant decompressor 330a may be an expansion valve or an expander for cooling the evaporation gas by thermally expanding the gas.

The evaporated gas cooled through the refrigerant decompressor 330a is supplied to the refrigerant heat exchanger 500a as refrigerant along the refrigerant circulation line CCLa and is supplied to the refrigerant heat exchanger 500a through the evaporation gas heat exchanger 200a And the evaporated gas is cooled through heat exchange with the evaporated gas. The evaporated gas of the refrigerant circulation line CCLa passing through the refrigerant heat exchanger 500a is circulated to the refrigerant compressor 310a and circulated through the refrigerant circulation line through the above-described compression and cooling processes.

Meanwhile, the evaporation gas of the evaporation gas re-liquefaction line (RLa) cooled by the refrigerant heat exchanger (500a) is decompressed through the first decompressor (600a). The first decompressor 600a may be an expansion valve, such as a Joule-Thomson valve, or an expander.

Liquid separated from the gas-liquid separator 700a, that is, the liquefied natural gas, is supplied to the storage tank T, and the liquid stored in the gas-liquid separator 700a is supplied to the gas-liquid separator 700a downstream of the first decompressor 600a Restored.

The gas separated from the gas-liquid separator 700a, that is, the evaporated gas is further depressurized via the second decompressor 800a, and is supplied to the evaporation gas heat exchanger 200a from the storage tank T, Or may be utilized as a cold / hot supply source that is joined to the gas flow or is again supplied to the evaporation gas heat exchanger 200a to heat-exchange the compressed high-pressure evaporation gas in the compressor 100a. Of course, it may be sent to a gas combustion unit (GCU) or the like, or it may be consumed by sending it to a fuel demanding place (including a gas engine).

FIG. 3 is a schematic view showing a system for processing an evaporative gas of a ship according to a second embodiment of the present invention.

3, the present embodiment is characterized in that the evaporation gas to be introduced from the cooler 320b to the refrigerant decompressor 330b in the refrigerant circulating unit 300b is cooled by heat exchange with the evaporated gas decompressed in the refrigerant decompressor 330b And then supplied to the refrigerant decompressor 330b.

Since the evaporation gas is cooled while being decompressed through the refrigerant decompressor 330b, the temperature of the evaporation gas downstream of the refrigerant decompression device is lower than the temperature of the evaporation gas upstream of the refrigerant decompression device. In this embodiment, Is cooled by heat exchange with the downstream evaporation gas, and then introduced into the decompression apparatus. To this end, the refrigerant heat exchanger 500b can supply evaporative gas upstream of the refrigerant decompressor 330b as shown in FIG. 3 (part A of FIG. 3). A separate heat exchanger capable of exchanging heat with the evaporation gas upstream and downstream of the refrigerant decompressor may be additionally provided.

As described above, the system of the present embodiments can re-liquefy and store the evaporated gas generated from the storage tank liquid cargo, thereby increasing the transportation rate of the liquid cargo. In particular, even when the consumption of fuel on the in-ship gas consumer is low, the amount of wasted cargo can be reduced or eliminated by burning in a gas combustion unit (GCU) in order to prevent the pressure rise of the storage tank, .

In addition, since the evaporation gas is circulated through the refrigerant and utilized as a heat source for re-liquefying the evaporated gas, the evaporated gas can be effectively re-liquefied without constructing a separate refrigerant cycle, and it is not necessary to supply a separate refrigerant. It contributes to secure space and is economical. In addition, if the refrigerant in the refrigerant cycle is insufficient, the refrigerant can be replenished from the storage tank to smoothly replenish the refrigerant, and the refrigerant cycle can be effectively operated.

In this way, the evaporation gas can be re-liquefied by using the cold and hot of the evaporation gas itself in multiple steps, and the system configuration for treating the evaporation gas on board can be simplified, and the cost required for installing and operating the apparatus for complicated evaporation gas processing Can be saved.

4 is a schematic view showing a system for processing an evaporative gas of a ship according to a third embodiment of the present invention.

Referring to FIG. 4, the ship of the present embodiment includes: an evaporative gas heat exchanger 110 installed downstream of the storage tank T; A compressor (120) and a first extra compressor (122) installed downstream of the evaporative gas heat exchanger (110) for compressing the evaporated gas discharged from the storage tank (T); A cooler 130 for lowering the temperature of the evaporated gas compressed by the compressor 120; A first extra cooler 132 for lowering the temperature of the evaporated gas compressed by the first extra compressor 122; A first valve (191) installed upstream of the compressor (120); A second valve 192 installed downstream of the cooler 130; A third valve (193) installed upstream of the first extra compressor (122); A fourth valve 194 installed downstream of the first extra cooler 132; A refrigerant heat exchanger (140) for additionally cooling the evaporated gas cooled by the evaporation gas heat exchanger (110); A refrigerant decompressor 160 for expanding the evaporated gas that has passed through the refrigerant heat exchanger 140 and then sending it to the refrigerant heat exchanger 140; And a first decompression device (150) for expanding the evaporated gas that is further cooled by the refrigerant heat exchanger (140).

The evaporated gas, which is naturally generated in the storage tank T and then discharged, is supplied to the fuel consumer 180 along the first supply line L1. The evaporation gas heat exchanger (110) is installed in the first supply line (L1) and recovers the cold heat from the evaporated gas immediately after being discharged from the storage tank (T). The ship of the present embodiment may further include a fifteenth valve 207 provided upstream of the fuel demanding place 180 for controlling the flow rate and the opening and closing of the evaporating gas sent to the fuel demanding place 180.

The evaporation gas heat exchanger 110 receives the evaporation gas discharged from the storage tank T and uses the evaporation gas as a refrigerant for cooling the evaporation gas supplied to the evaporation gas heat exchanger 110 along the return line L3. On the return line L3, a fifth valve 195 for regulating the flow rate and opening / closing of the evaporation gas may be installed.

The compressor (120) and the first extra compressor (122) compress the evaporative gas that has passed through the evaporative gas heat exchanger (110). The compressor 120 is installed on the first supply line L1 and the first extra compressor 122 is installed on the second supply line L2. The second supply line L2 is branched from the first supply line L1 upstream of the compressor 120 and connected to the first supply line L1 downstream of the compressor 120. [ In addition, the compressor 120 and the first extra compressor 122 may be installed in parallel and may be compressors of the same performance.

In general, the ship is additionally provided with a first extra compressor 122 and a first extra cooler 132 in case the compressor 120 and the cooler 130 fail. Conventionally, the first extra compressor 122 and the first extra cooler 132 are not used in a normal state in which the compressor 120 or the cooler 130 fails.

That is, conventionally, when the compressor 120 or the cooler 130 fails, the third valve 193 upstream of the first extra compressor 122 and the fourth valve 193 downstream of the first extra cooler 132 194 are closed so that the evaporated gas passes through the compressor 120 and the cooler 130 to be supplied to the fuel consumer 180. When the compressor 120 or the cooler 130 fails, the first extra compressor 122 And the fourth valve 194 downstream of the first extra cooler 132 are opened and the first valve 191 upstream of the compressor 120 and the second valve 193 downstream of the cooler 130 are opened, The evaporator 192 is closed so that the evaporated gas passes through the first extra compressor 122 and the first extra cooler 132 to be supplied to the fuel consumer 180.

The present invention is to increase the efficiency of re-liquefaction of the evaporation gas and the amount of re-liquefaction by using the first extra compressor (122) and the first extra cooler (132) A part of the evaporated gas compressed by the compressor 122 is sent to the fuel consumer 180 and the other part is used as a refrigerant that further cools the evaporated gas in the refrigerant heat exchanger 140.

6 is a graph schematically illustrating the phase change of methane with temperature and pressure. Referring to FIG. 6, methane enters a supercritical fluid state at a temperature of approximately -80 DEG C or higher and a pressure of approximately 55 bar or higher. That is, in the case of methane, the critical point is about -80 ° C, 55 bar. The supercritical fluid state is a third state different from the liquid state or gas state.

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 ".

The evaporated gas compressed by the compressor 120 or the first extra compressor 122 may be in a gaseous state or in a supercritical fluid state depending on the degree of compression.

When the evaporation gas sent to the evaporation gas heat exchanger 110 through the return line L3 is in a gaseous state, the evaporation gas passes through the evaporation gas heat exchanger 110 and the temperature is lowered to become a mixture state of the liquid and the gas And in the case of a supercritical fluid state, the temperature can be lowered through the evaporation gas heat exchanger 110 to become "high-pressure liquid state ".

The temperature of the evaporated gas cooled by the evaporated gas heat exchanger 110 becomes lower while passing through the refrigerant exchanger 140. The evaporated gas passing through the evaporated gas heat exchanger 110 is mixed with the liquid The refrigerant passes through the refrigerant heat exchanger 140 and the temperature of the refrigerant is further lowered so that the ratio of the liquid becomes higher or becomes the liquid state. In the case of the "high-pressure liquid state & So that the temperature is lowered.

Further, even when the evaporated gas that has passed through the refrigerant heat exchanger 140 is in the "high pressure liquid state ", the evaporated gas passes through the first decompressor 150 and becomes low in pressure, do.

Even if the pressure of the evaporation gas is lowered to the same degree (P in FIG. 6) by the first decompressor 150, the temperature is lower than that in the case where the temperature is higher (X → X ' (Y - > Y 'in Fig. 6), the ratio of the liquid becomes higher. Further, if the temperature can be further lowered, it is theoretically possible to re-liquefy 100% of the evaporated gas (Z → Z 'in FIG. 6). Therefore, if the evaporation gas is further cooled by the refrigerant heat exchanger 140 before passing through the first decompressor 150, the re-liquefaction efficiency and the liquefaction amount can be increased.

Referring to FIG. 4 again, this embodiment is different from the first embodiment and the second embodiment in that refrigerant circulation parts 300a and 300b for further cooling the evaporation gas are constituted by a closed loop, Loop configuration.

In the first and second embodiments, the refrigerant circulation units 300a and 300b are constituted by closed loops, and the evaporated gas compressed by the refrigerant compressors 310a and 310b flows from the refrigerant heat exchangers 500a and 500b to the refrigerant It can not be sent to the fuel consumer, or it can not go through the liquefaction process.

On the other hand, in the present embodiment, the refrigerant cycle is formed as an open loop so that the evaporated gas compressed by the first extra compressor 122 is merged with the evaporated gas compressed by the compressor 120, and then a part of the combined evaporated gas The other part is used as the refrigerant in the refrigerant heat exchanger 140 along the recycle line L5 and the remaining part is subjected to the liquefaction process along the return line L3.

The recycle line L5 is a line that branches from the first supply line L1 downstream of the compressor 120 and is connected to the first supply line L1 upstream of the compressor 120. [ A sixth valve 196 for regulating the flow rate and opening and closing of the evaporation gas may be provided on the recycle line L5 where the evaporated gas branched from the first supply line L1 is sent to the refrigerant heat exchanger 140. [

The present embodiment in which the refrigerant cycle is configured as an open loop is different from the first and second embodiments in which the refrigerant cycle is constituted by a closed loop and the downstream line of the compressor 120 and the downstream line of the first extra compressor 122 are connected There is a big difference in point. That is, in the present embodiment, the second supply line L2 downstream of the first redundant compressor 122 is connected to the first supply line L1 downstream of the compressor 120, The compressed evaporated gas is combined with the evaporated gas compressed by the compressor 120 and then sent to the refrigerant heat exchanger 140, the fuel consumer 180, or the evaporative gas heat exchanger 110. The present embodiment includes all other modifications in which the downstream line of the compressor 120 and the downstream line of the first redundant compressor 122 are connected.

Therefore, according to the present embodiment, when the demanded amount at the fuel demanding place 180 increases, for example, as the ship's operating speed increases, not only the evaporated gas compressed by the compressor 120 but also the evaporated gas compressed by the first extra compressor 122 The evaporated gas compressed by the evaporator can also be sent to the fuel demanding unit 180.

Generally, however, since the compressor 120 and the first extra compressor 122 are designed to have a capacity of about 1.2 times the amount required in the fuel consumer 180, The evaporated gas compressed by the extra compressor 122 hardly needs to be sent to the fuel demanding unit 180. [ Rather, if the evaporated gas discharged from the storage tank T can not be consumed by the fuel consumer 180 and the evaporative gas to be re-liquefied increases, a large amount of refrigerant is required to re-liquefy a large amount of evaporated gas More frequent.

According to this embodiment, not only the evaporated gas compressed by the compressor 120 but also the evaporated gas compressed by the first extra compressor 122 can be used as a refrigerant for heat exchange in the refrigerant heat exchanger 140, The evaporation gas supplied to the refrigerant heat exchanger 140 along the return line L3 after passing through the gas heat exchanger 110 can be cooled to a lower temperature by using more refrigerant and the overall re- The liquefaction amount can be increased, and theoretically, 100% liquefaction is possible.

Generally, when determining the capacities of the compressors 120 and 122 installed on the ship, the capacity required for supplying the evaporative gas to the fuel consumer station 180 and the evaporative gas remaining not consumed in the fuel consumer station 180 are re- In this embodiment, the amount of liquefaction can be increased by using the extra compressor 122, so that the capacity required for re-liquefaction can be reduced, and the capacity of the compressors 120, 122 can be installed. Reducing the capacity of the compressor has the advantage of saving both equipment installation and operating costs.

In this embodiment, not only the first valve 191 and the second valve 192 but also the third valve 193 and the fourth valve 194, as well as the first valve 191 and the second valve 192, Both the compressor 120, the cooler 130, the first extra compressor 122 and the first extra cooler 132 are operated and when the compressor 120 or the cooler 130 fails, The first valve 191 and the second valve 192 are closed and only the evaporated gas that has passed through the first extra compressor 122 and the first extra cooler 132 is returned to the system To operate.

The compressor 120 and the cooler 130 have a main role and the first extra compressor 122 and the first extra cooler 132 serve as an auxiliary function. The first extra compressor 122, the cooler 130, and the first extra cooler 132 have the same role, and one or more vessels may have two or more compressors and coolers, In this case, it is possible to substitute other equipment to meet the concept of redundancy. Hereinafter, the same applies.

Accordingly, even when the first extra compressor 122 or the first extra cooler 132 fails, it is possible to give up the increase in the liquefaction efficiency and the amount of resolidification, as in the case where the compressor 120 or the cooler 130 fails The third valve 193 and the fourth valve 194 are closed and the system is operated only by the evaporated gas that has passed through the compressor 120 and the cooler 130.

On the other hand, when the ship is operated at a high speed such that most or all of the evaporative gas discharged from the storage tank T can be used as fuel for the fuel consumer 180, the amount of the evaporative gas to be re- Or disappear. Accordingly, when the ship is operated at a high speed, only one of the compressor 120 and the extra compressor 122 may be driven.

The compressor 120 and the first redundant compressor 122 may compress the evaporative gas at a pressure required by the fuel consumer 180. The fuel consumer 180 may be an engine, . For example, if the fuel consumer 180 is a marine propulsion engine, the compressor 120 and the first extra compressor 122 may compress the evaporation gas to a pressure of approximately 10-100 bar.

The compressor 120 and the first redundant compressor 122 can also compress the evaporation gas to a pressure of approximately 150 bar to 400 bar when the fuel consumer 180 is an ME-GI engine, In the case of DFDE, the evaporation gas can be compressed to a pressure of approximately 6.5 bar and, if the fuel consumer 180 is an X-DF engine, the evaporation gas can be compressed to a pressure of approximately 16 bar.

The fuel demanding unit 180 may include various types of engines. For example, when the fuel demanding unit 180 includes the X-DF engine and the DFDE, the compressor 120 and the first redundant compressor 122 may be connected to the X- The evaporation gas is compressed to the pressure demanded by the DF engine and a pressure reducing device is installed upstream of the DFDE to supply a portion of the compressed evaporated gas down to the pressure required by the X-DF engine to the pressure required by the DFDE, It is possible.

In addition, in order to increase the re-liquefaction efficiency and the amount of re-liquefaction in the evaporative gas heat exchanger 110 and the refrigerant heat exchanger 140, the pressure of the evaporative gas is increased by the compressor 120 or the first extra compressor 122 The evaporation gas is compressed so as to exceed the pressure demanded by the fuel demanding unit 180 and a pressure reducing device is installed upstream of the fuel demanding unit 180 so that the pressure of the compressed evaporating gas is increased to exceed the pressure demanded by the fuel demanding unit 180 It may be supplied to the fuel demanding place 180 after lowering it to a pressure demanded by the fuel demanding place 180.

Meanwhile, the compressor 120 and the first redundant compressor 122 may be multi-stage compressors, respectively. 4 illustrates compressing the evaporated gas to a pressure required by the fuel consumer 180 by one compressor 120 or 122. However, when the compressor 120 and the first redundant compressor 122 are multi-stage compressors , The evaporation gas can be compressed several times by the plurality of compression cylinders to the pressure required by the fuel consumer 180.

When the compressor 120 and the first redundant compressor 122 are multi-stage compressors, a plurality of compression cylinders may be installed in series in the compressor 120 and the first redundant compressor 122, A plurality of coolers may be installed, respectively.

The cooler 130 of the present embodiment is installed downstream of the compressor 120 and is cooled by the compressor 120 so as to cool not only the pressure but also the temperature of the evaporated gas, and the first extra cooler 132 of this embodiment, Is installed downstream of the first extra compressor 122 and is compressed by the first extra compressor 122 to cool not only the pressure but also the evaporated gas whose temperature has risen. The cooler 130 and the first extra cooler 132 can cool the evaporated gas through heat exchange with seawater, fresh water, or air introduced from the outside.

The refrigerant heat exchanger 140 of the present embodiment further cools the evaporation gas supplied to the refrigerant heat exchanger 140 along the return line L3 after being cooled by the evaporation gas heat exchanger 110, The decompression device 160 expands the evaporated gas that has passed through the refrigerant heat exchanger 140, and then sends it to the refrigerant heat exchanger 140.

That is, the refrigerant heat exchanger 140 expands the evaporation gas supplied to the refrigerant heat exchanger 140 along the return line L3 after passing through the evaporation gas heat exchanger 110, by the refrigerant pressure-reducing device 160, Exchanges the evaporated gas with the refrigerant, and further cools it.

The refrigerant pressure reducing device 160 of this embodiment may be various means for lowering the pressure of the fluid. The state of the fluid just before passing through the refrigerant depressurization device 160 and the state of the fluid just after passing through the refrigerant pressure- Can vary. However, when the refrigerant pressure-reducing device 160 is an inflator, in order to prevent physical damage to the refrigerant pressure-reducing device 160, the fluid just before passing through the refrigerant pressure-reducing device 160 and the fluid just after passing through the refrigerant pressure- . Hereinafter, the same applies.

The evaporation gas used as the refrigerant for the heat exchange in the refrigerant heat exchanger 140 after passing through the refrigerant decompressor 160 is supplied to the evaporator 130 through the evaporator 130. The evaporation gas compressed by the compressor 120 is evaporated by the first extra compressor 122, A portion of the combined vaporized gas is supplied to the refrigerant heat exchanger 140 along the recycle line L5 so that the evaporated gas that has passed through the refrigerant depressurization device 160 in the refrigerant heat exchanger 140 is introduced into the refrigerant Exchanged with refrigerant, cooled, and then supplied to the refrigerant pressure-reducing device 160.

The evaporated gas supplied from the first supply line L1 to the refrigerant heat exchanger 140 along the recycle line L5 is primarily cooled by the refrigerant heat exchanger 140 and is further cooled by the refrigerant decompression device 160 Cooled, and then sent to the refrigerant heat exchanger (140) for use as a refrigerant.

That is, the flow of the evaporated gas compressed by the compressor 120 is merged with the evaporated gas compressed by the first extra compressor 122 and then supplied to the refrigerant heat exchanger 140 along the recycle line L5; The evaporation gas supplied to the refrigerant heat exchanger 140 along the return line L3 after passing through the evaporation gas heat exchanger 110 is used as the refrigerant through the evaporation gas that has passed through the refrigerant decompression device 160, Exchanged and cooled.

The first decompression device 150 of the present embodiment is installed on the return line L3 to expand the evaporation gas cooled by the evaporation gas heat exchanger 110 and the refrigerant heat exchanger 140. [ The evaporated gas compressed by the compressor 120 is merged with the evaporated gas compressed by the first redundant compressor 122 and then partially branched and discharged along the return line L3 to the evaporation gas heat exchanger 110, Passes through the first pressure reducing device (140) and the first pressure reducing device (150), and part or all of the liquid is re-liquefied.

The first decompression device 150 includes all means capable of expanding and cooling the evaporation gas, and may be an expansion valve, such as a Joule-Thomson valve, or an expander.

The vessel of the present embodiment has a gas-liquid separator 170 installed on a return line L3 downstream of the first decompressor 150 and separating the gas-liquid mixture discharged from the first decompressor 150 into gas and liquid .

When the vessel of the present embodiment does not include the gas-liquid separator 170, the liquid or the gas-liquid mixed vaporized gas that has passed through the first decompressor 150 is directly sent to the storage tank T.

When the vessel of the present embodiment includes the gas-liquid separator 170, the vaporized gas that has passed through the first decompressor 150 is sent to the gas-liquid separator 170 to separate the gas phase and the liquid phase. The liquid separated by the gas-liquid separator 170 returns to the storage tank T along the return line L3 and the gas separated by the gas-liquid separator 170 flows from the gas-liquid separator 170 to the evaporation gas heat exchanger To the evaporation gas heat exchanger 110 along a gas discharge line L4 that extends to the first supply line L1 upstream of the gas supply line L1.

A seventh valve 197 for regulating the flow rate of the liquid separated by the gas-liquid separator 170 and sent to the storage tank T when the ship of this embodiment includes the gas-liquid separator 170; And an eighth valve (198) for controlling the flow rate of the gas separated by the gas-liquid separator (170) and sent to the evaporation gas heat exchanger (110).

(191, 192, 193, 194, 195, 196, 197, 198, 207) of the first to eighth valves and the fifteenth valve of this embodiment can be manually adjusted And may be automatically adjusted to be opened or closed by a preset value.

The main flow of the evaporating gas is defined to facilitate the operation of the apparatus for evaporating gas re-liquefaction according to an embodiment of the present invention. The flow of the evaporated gas generated in the storage tank T and the gas discharged from the gas-liquid separator 170 is supplied to the evaporative gas heat exchanger 110 in the first flow 100, the evaporative gas heat exchanger 110, The compressor 120 and the first redundant compressor 122 to supply the second stream 102 and the refrigerant to the fuel consumer 180. The second stream 102 is supplied to the compressor 120 and the first extra compressor 122, And downstream of the first extra compressor 122 to the refrigerant heat exchanger 140 from the second stream 102 to the downstream of the third stream 104, the compressor 120 and the first extra compressor 122 The flow that is branched from the second flow 102 and supplied to the evaporation gas heat exchanger 110 is referred to as the fourth flow 106 and the flow supplied from the evaporation gas heat exchanger 110 to the refrigerant heat exchanger 140 is referred to as the fifth flow Is defined as a flow (108). The first stream 100 passes through the evaporative gas heat exchanger 110 and becomes the second stream 102 while the fourth stream 106 passes through the evaporative gas heat exchanger 110 and the fifth stream 108 do.

Hereinafter, the operation of the apparatus for evaporating gas re-liquefaction according to an embodiment of the present invention will be described with reference to FIG. The present embodiment is particularly suitable for the case where the liquefied gas stored in the storage tank is liquefied natural gas and the demand for fuel is X-DF, but is not limited thereto. The same is true for the fourth embodiment.

The gaseous vaporized gas produced in the storage tank T for storing the liquefied gas in the liquid state is supplied to the vaporized gas heat exchanger 110. At this time, the gaseous evaporation gas generated in the storage tank T meets the gaseous evaporation gas discharged from the gas-liquid separator 170 after a certain period of time has elapsed from the operation of the system to form the first stream 100 do. The evaporation gas ultimately supplied to the evaporative gas heat exchanger 110 is the first flow 100.

The evaporation gas heat exchanger 110 collects cold heat of the first flow 100 to cool the other evaporation gas. That is, the evaporative gas heat exchanger 110 recovers the cold heat of the first stream 100 and supplies it to the evaporative gas heat exchanger 110 of the second stream 102, that is, (106).

Thus, in the evaporative gas heat exchanger 110, heat exchange occurs between the first stream 100 and the fourth stream 106 so that the first stream 100 is heated and the fourth stream 106 is cooled. The heated first stream 100 becomes the second stream 102 and the cooled fourth stream 106 becomes the fifth stream 108. [

The second stream 102 discharged from the evaporative gas heat exchanger 110 is supplied to the compressor 120 or the first redundant compressor 122 and compressed by the compressor 120 or the first redundant compressor 122 .

The second stream 102, in which the evaporated gas compressed by the compressor 120 and the evaporated gas compressed by the first redundant compressor 122 are combined, is partly transferred to the refrigerant heat exchanger 140 as the third stream 104 And the other part is supplied to the evaporation gas heat exchanger 110 as the fourth flow 106 to be cooled and the remaining part thereof is supplied to the fuel consuming place 180. [

The third flow 104 supplied to the refrigerant heat exchanger 140 is discharged from the refrigerant heat exchanger 140 and expanded in the refrigerant pressure reducing device 160 and then supplied to the refrigerant heat exchanger 140. The third flow 104 supplied to the refrigerant heat exchanger 140 first flows through the third flow 104 which is expanded in the refrigerant pressure reducing device 160 and then supplied to the refrigerant heat exchanger 140, Exchanged and cooled. The third stream 104 that has passed through the refrigerant decompressor 160 and the refrigerant heat exchanger 140 merges with the second stream 102 that is discharged from the evaporative gas heat exchanger 110, 1 < / RTI >

The fourth stream 106 cooled by the heat exchange with the first stream 100 in the evaporative gas heat exchanger 110 becomes the fifth stream 108 and is supplied to the refrigerant heat exchanger 140. The fifth stream 108 supplied to the refrigerant heat exchanger 140 is heat-exchanged with the third stream 104 that has passed through the refrigerant depressurizing device 160 and is then cooled and passes through the first pressure reducing device 150, do. The fifth stream 108, which has passed through the first decompression device 150, becomes a vapor-liquid mixture state in which gas and liquid are mixed.

The fifth stream 108 in the vapor-liquid mixture state is immediately sent to the storage tank T or separated into gas and liquid as it passes through the gas-liquid separator 170. The liquid separated by the gas-liquid separator 170 is supplied to the storage tank T, and the gas separated by the gas-liquid separator 170 is supplied to the evaporation gas heat exchanger 110 to repeat the above processes.

5 is a schematic view showing a system for processing an evaporative gas of a ship according to a fourth embodiment of the present invention.

The ship according to the fourth embodiment shown in Fig. 5 is different from the ship according to the third embodiment shown in Fig. 4 in that the second extra compressor 124, the second extra cooler 134, the third supply line L6, 1 additional line L7, a second additional line L8 and a ninth valve to a fourteenth valve 201, 202, 203, 204, 205 and 206, There are differences in the following, and the differences are mainly described below. The detailed description of the same members as those of the ship of the third embodiment will be omitted.

5, the vessel of the present embodiment includes an evaporation gas heat exchanger 110, a first valve 191, a compressor 120, a cooler 130, a second valve 192, The third valve 193, the first extra compressor 122, the first extra cooler 132, the fourth valve 194, the refrigerant heat exchanger 140, the refrigerant pressure reducing device 160, (150).

However, unlike the third embodiment, the ship of the present embodiment includes a ninth valve 201 installed on the recirculation line L5; A third supply line L6 branched from the second supply line L2 and connected to the recycle line L5; A second extra compressor (124) installed on the third supply line (L6) for compressing the evaporative gas discharged from the storage tank (T); A second extra cooler 134 installed downstream of the second extra compressor 124 of the third supply line L6 to lower the temperature of the evaporated gas compressed by the second extra compressor 124; A tenth valve (202) installed on a third supply line (L6) upstream of the second extra compressor (124); A twelfth valve (204) installed on the recirculation line (L5) between the second supply line (L2) and the third supply line (L6); A first additional line L7 connecting between the recycle line L5 and the third supply line L6; A second additional line L8 connecting between the first additional line L7 and the second supply line L2; A thirteenth valve (205) installed on the first additional line (L7); And a fourteenth valve (206) installed on the second additional line (L8).

The vessel of the present embodiment is installed on the recirculation line L5 between the first supply line L1 and the second supply line L2 unlike the third embodiment which selectively includes the sixth valve And a sixth valve (196).

In addition, the ship of the present embodiment is different from the third embodiment in that the second supply line L2 on the downstream side of the first extra compressor 122 is connected to the recycle line L5 rather than the first supply line L1 do. That is, the recirculation line L5 of this embodiment is branched from the first supply line L1 and is connected sequentially to the downstream end of the second supply line L2, the downstream end of the third supply line L6 To the refrigerant heat exchanger (140).

The storage tank T of this embodiment stores therein liquefied natural gas such as liquefied natural gas or liquefied ethane gas, and discharges the evaporated gas to the outside when the internal pressure becomes equal to or higher than a predetermined pressure, as in the third embodiment. The evaporation gas discharged from the storage tank (T) is sent to the evaporation gas heat exchanger (110).

The evaporation gas heat exchanger 110 of this embodiment is configured such that the evaporation gas discharged from the storage tank T is used as the refrigerant and the refrigerant is discharged to the evaporation gas heat exchanger 110 along the return line L3 Cool the evaporated gas sent. That is, the evaporation gas heat exchanger 110 recovers the cold heat of the evaporation gas discharged from the storage tank T and supplies the recovered cold heat to the evaporation gas sent to the evaporation gas heat exchanger 110 along the return line L3 Supply. On the return line L3, a fifth valve 195 for regulating the flow rate and opening / closing of the evaporation gas may be installed.

The compressor 120 of the present embodiment is provided on the first supply line L1 to compress the evaporated gas discharged from the storage tank T and supply the compressed refrigerant to the first extra compressor 122 Is installed in parallel with the compressor 120 on the second supply line L2 to compress the evaporated gas discharged from the storage tank T as in the third embodiment.

The second extra compressor 124 of the present embodiment is installed in parallel with the compressor 120 and the first extra compressor 122 on the third supply line L6 to supply the evaporated gas discharged from the storage tank T Compression. The compressor 120, the first extra compressor 122, and the second extra compressor 124 may be compressors of the same performance, each being a multi-stage compressor.

Since the ship of this embodiment includes not only the first extra compressor 122 but also the second extra compressor 124, it is economical to use a compressor having a small capacity. The compressor 120, the first extra compressor 122, and the second extra compressor 124 must function as a failed compressor (or an extra compressor) when one of them fails, For example, when a compressor requires a total of 150 capacitors to process an evaporative gas, it is better to provide a compressor with a capacity of 50 each, rather than a compressor with a capacity of 75 and an extra compressor, And installing two extra compressors is much less expensive. That is, the vessel of the present embodiment can further include one extra compressor, so that it can process the same or a larger amount of evaporated gas at a lower cost.

In addition, since the ship of the present embodiment includes not only the first extra compressor 122 but also the second extra compressor 124, it is possible to operate the system more finely and flexibly according to the speed of the ship.

If the amount of the liquefied gas in the storage tank T is large, the amount of evaporated gas is increased. If the ship is operated at a low speed, the amount of evaporated gas in the fuel consuming place 180 is reduced. The amount of the liquefied gas in the tank T increases, and as the speed of the ship becomes slower, the amount of liquefied gas in the storage tank T decreases and the speed of the ship decreases.

Although the amount of liquefied gas in the storage tank T is variable, when the liquefied gas carrier is taken as an example, the amount of liquefied gas in the storage tank T is large when the liquefied gas is transported from the place of production to the customer, Considering the amount of liquefied gas in the storage tank T together, for example, when operating a ship at a high speed (approximately 18 to 19 knots), only one of the three compressors 120, 122, 124 is used, When the ship is operating at low speeds (approximately 13 to 14 knots), two systems are used, and when the ship is at bay, all three systems can be operated.

If only one extra compressor is installed in addition to the compressor, if the compressor or the redundant compressor fails, the evaporative gas can be treated by using only one compressor (or an extra compressor) that fails to give rise to the improvement in the re-liquefaction efficiency The concept of redundancy can be satisfied. However, since the compressor and the redundant compressor are both operated for almost the most of the time the ship is operating, the concept of redundancy can not but be weakened.

However, since the time required for the ship to travel at a high speed is short compared to the time when the ship is operated at low speed or anchored, according to the present embodiment, the time required for all of the compressors installed in the ship is minimized, The concept can be sufficiently secured.

On the other hand, the compressor 120, the first extra compressor 122, and the second extra compressor 124 of this embodiment can compress the evaporation gas to a pressure required by the fuel demanding place 180. When the fuel demanding unit 180 includes various kinds of engines, the evaporating gas is compressed in accordance with the required pressure of the engine requiring a higher pressure (hereinafter referred to as a "high-pressure engine"), Pressure engine provided downstream of the engine (hereinafter referred to as a " low-pressure engine ") which supplies the engine to the engine and the other part that requires a lower pressure. In addition, in order to increase the re-liquefaction efficiency and the amount of resolidification in the evaporative gas heat exchanger 110 and the refrigerant heat exchanger 140, the high- A decompression device may be provided upstream and the pressure of the evaporation gas compressed at a high pressure may be lowered to a pressure required by the fuel consumption site 180 and then supplied to the fuel consumption site 180.

The ship of the present embodiment can use the evaporated gas compressed by the first extra compressor 122 and the second redundant compressor 124 as a refrigerant for further cooling the evaporation gas in the refrigerant heat exchanger 140, And the amount of liquefaction can be increased.

As in the third embodiment, the cooler 130 of this embodiment is installed downstream of the compressor 120 to cool the evaporated gas passing through the compressor 120 and not only the pressure but also the temperature, The cooler 132 is installed downstream of the first extra compressor 122 and passes through the first extra compressor 122 to cool not only the pressure but also the temperature of the evaporated gas, as in the third embodiment. The second extra cooler 134 of this embodiment is installed downstream of the second extra compressor 124 and passes through the second extra compressor 124 to cool the evaporated gas as well as the pressure as well as the temperature.

The fuel demanding unit 180 of this embodiment may be any one of an ME-GI engine, an X-DF engine, a DFDE, and a gas turbine engine as in the third embodiment and includes a compressor 120, a first extra compressor 122, And the second extra compressor 124 may compress the evaporation gas to a pressure of approximately 150 bar to 400 bar when the fuel consumer 180 is an ME-GI engine and the evaporation gas Can be compressed to a pressure of approximately 6.5 bar, and if the fuel consumer 180 is an X-DF engine, the evaporation gas can be compressed to a pressure of approximately 16 bar. A fifteenth valve 207 capable of regulating the flow rate and opening and closing of the evaporation gas supplied to the fuel demanding place 180 may be installed upstream of the fuel demanding place 180.

One side of the third supply line L6 of this embodiment is connected to the second supply line L2 upstream of the third valve 193 and the other side of the third supply line L6 is connected to the recirculation line L5 upstream of the twelfth valve 204 .

One side of the first additional line L7 of the present embodiment is a recirculation line L1 which is expanded by the refrigerant decompression device 160 and then sent to the first supply line L1 through the refrigerant heat exchanger 140. [ L5 and the other side is connected to a third supply line L6 between the tenth valve 202 and the second extra compressor 124. [

One side of the second additional line L8 of the present embodiment is connected to the first additional line L7 upstream of the thirteenth valve 205 and the other side is connected to the third valve 193 and the first extra compressor 122, To the second supply line L2 between the first supply line L2 and the second supply line L2.

The ninth valve 201 of the present embodiment is arranged so that the point where the recycle line L5 meets the first supply line L1 upstream of the compressor 120 and the redundant compressors 122 and 124 and the point where the recycle line L5 1 additional line L7, and regulates the flow rate and the opening and closing of the evaporation gas.

The refrigerant heat exchanger 140 of this embodiment is supplied to the evaporation gas heat exchanger 110 along the return line L3 in the same manner as in the third embodiment to supply the evaporation gas cooled by the evaporation gas heat exchanger 110 Further cooling.

According to this embodiment, as in the third embodiment, the evaporated gas discharged from the storage tank T is further cooled not only in the evaporative gas heat exchanger 110 but also in the refrigerant heat exchanger 140, Can be supplied to the first decompression device 150, so that the re-liquefaction efficiency and the amount of liquefaction can be increased.

As in the third embodiment, the refrigerant pressure reducing device 160 of the present embodiment expands the evaporated gas that has passed through the refrigerant heat exchanger 140, and then sends it to the refrigerant heat exchanger 140 again.

The first decompression device 150 of the present embodiment is provided on the return line L3 in the same manner as the third embodiment and is provided with the evaporation gas cooled by the evaporation gas heat exchanger 110 and the refrigerant heat exchanger 140 Expand. The first decompression device 150 of the present embodiment includes all means capable of expanding and cooling the evaporation gas and may be an expansion valve such as a Joule-Thomson valve or an expander.

The vessel of this embodiment is provided on the return line L3 downstream of the first decompressor 150 and separates the gas-liquid mixture discharged from the first decompressor 150 into gas and liquid, as in the third embodiment , And a gas-liquid separator (170).

When the vessel of the present embodiment does not include the gas-liquid separator 170, the liquid or the gas-liquid mixed vaporized gas that has passed through the first decompressor 150 is directly sent to the storage tank T as in the third embodiment When the ship of this embodiment includes the gas-liquid separator 170, the evaporated gas that has passed through the first decompressor 150 is sent to the gas-liquid separator 170 to separate the gas phase and the liquid phase. The liquid separated by the gas-liquid separator 170 returns to the storage tank T along the return line L3 and the gas separated by the gas-liquid separator 170 flows from the gas-liquid separator 170 to the evaporation gas heat exchanger To the evaporation gas heat exchanger 110 along a gas discharge line L4 that extends to the first supply line L1 upstream of the gas supply line L1.

The seventh valve 197 (hereinafter, referred to as " 197 ") for regulating the flow rate of the liquid separated by the gas-liquid separator 170 and sent to the storage tank T as in the third embodiment, ); And an eighth valve (198) for controlling the flow rate of the gas separated by the gas-liquid separator (170) and sent to the evaporation gas heat exchanger (110).

The first to fifteenth valves 191, 192, 193, 194, 195, 196, 197, 198, 201, 202, 203, 204, 205, 206, And may be automatically adjusted to be opened or closed by a preset value.

The ship of the present embodiment is different from the third embodiment in that the first additional line L7, the second additional line L8, the sixth valve 196, the ninth valve 201, the twelfth valve 204, The thirteenth valve 205 and the fourteenth valve 206 and the second supply line L2 and the third supply line L6 are connected directly to the recycle line L5, The refrigerant cycle can be operated as a closed loop as in the first and second embodiments or as an open loop as in the third embodiment. Hereinafter, a method of operating the refrigerant cycle as a closed loop and a method of operating the refrigerant cycle as an open loop will be described through valve control.

The evaporation gas compressed by the second extra compressor 124 is used as the refrigerant in the refrigerant heat exchanger 140 while the refrigerant cycle of the ship of this embodiment is operated in the closed loop and the evaporation gas compressed by the compressor 120 The first valve 191 and the second valve 182 are connected to each other so that the evaporated gas compressed by the first extra compressor 122 is sent to the fuel consumer 180 or is re-liquefied The second valve 192, the third valve 193, the fourth valve 194, the sixth valve 196, the tenth valve 202, the eleventh valve 203, the thirteenth valve 205, The fifteenth valve 207 is opened and the ninth valve 201, the twelfth valve 204 and the fourteenth valve 206 are driven in a closed state.

When the evaporated gas compressed by the second redundant compressor 124 after being discharged from the storage tank T is supplied to the recycle line L5, the tenth valve 202 is closed and the evaporated gas is supplied to the second extra compressor 124 The second extra cooler 134, the eleventh valve 203, the refrigerant heat exchanger 140, the refrigerant pressure reducing device 160, the refrigerant heat exchanger 140, and the thirteenth valve 205, Thereby forming a closed loop refrigerant cycle.

When the refrigerant cycle is constituted by a closed loop, nitrogen gas may be used as the refrigerant circulating in the closed loop. In this case, the ship of the present embodiment may further include a pipe for introducing the nitrogen gas into the refrigerant cycle of the closed loop.

When the refrigerant cycle is operated as the first closed loop, only the evaporated gas circulating in the closed loop is used as the refrigerant in the refrigerant heat exchanger 140, and the evaporated gas passing through the compressor 120 or the first extra compressor 122 Is not introduced into the refrigerant cycle and is supplied to the fuel consumer 180 or is re-liquefied along the return line L3. Therefore, the evaporation gas at a constant flow rate is circulated to the refrigerant in the refrigerant heat exchanger 140 irrespective of the amount of resolidification or the amount of evaporation gas required by the fuel demanding unit 180.

The operation of the refrigerant cycle as the first closed loop is suitable when the amount demanded by the fuel consumer site 180 is large and the amount of evaporative gas to be liquefied is small.

The flow of the evaporative gas in the case where the refrigerant cycle of the ship of this embodiment is operated as the first closed loop will be described as follows.

The evaporated gas discharged from the storage tank T is diverted into two flows after passing through the evaporative gas heat exchanger 110. One stream is compressed by the compressor 120 along the first supply line L1, (130) and the other stream is compressed by the first extra compressor (122) along the second supply line (L2) and then cooled by the first extra cooler (132).

The evaporation gas that has passed through the compressor 120 and the cooler 130 along the first feed line L1 and the first extra compressor 122 and the second extra cooler 134 along the second feed line L2 The passing evaporated gas is merged in the recycle line L5, a portion is sent to the fuel consumer 180, and the remaining portion is sent to the evaporation gas heat exchanger 110 along the return line L3. The evaporated gas sent to the evaporation gas heat exchanger 110 along the return line L3 is heat-exchanged with the evaporated gas discharged from the storage tank T and is then cooled in the refrigerant heat exchanger 140 to be further cooled.

The evaporated gas cooled by the evaporative gas heat exchanger (110) and the refrigerant heat exchanger (140) is expanded by the first decompressor (150) to partially or totally re-liquefy. In the case where the ship of this embodiment does not include the gas-liquid separator 170, the evaporated gas partially or totally re-liquefied is directly sent to the storage tank T. When the ship of this embodiment includes the gas-liquid separator 170 The evaporated gas partially or totally re-liquefied is sent to the gas-liquid separator 170. The gas separated by the gas-liquid separator 170 is combined with the evaporated gas discharged from the storage tank T and sent to the evaporation gas heat exchanger 110. The liquid separated by the gas-liquid separator 170 flows into the storage tank T).

Meanwhile, the evaporated gas circulating the refrigerant cycle is compressed by the second extra compressor 124, cooled by the second extra cooler 134, and then sent to the refrigerant heat exchanger 140 along the recycle line L5 . The evaporated gas that has passed through the second extra compressor 124 and the second extra cooler 134 and then sent to the refrigerant heat exchanger 140 is firstly heat-exchanged in the refrigerant heat exchanger 140 and cooled, ), And is expanded and cooled by a second order. The evaporated gas that has passed through the refrigerant decompressor 160 is again sent to the refrigerant heat exchanger 140. The evaporated gas is supplied to the refrigerant heat exchanger 140 along the return line L3 after passing through the evaporating gas heat exchanger 110, gas; And the evaporation gas compressed by the second extra compressor 124 and then supplied to the refrigerant heat exchanger 140 along the recycle line L5. The evaporated gas used as the refrigerant in the refrigerant heat exchanger 140 after passing through the refrigerant decompressor 160 is again sent to the second extra compressor 124, and the above-described series of processes is repeated.

The first valve 191, the second valve 192, and the thirteenth valve 205 (or 205), when the compressor 120 or the cooler 130 fails while the refrigerant cycle of the ship of this embodiment is being operated as the first closed loop, And the tenth valve 202 and the twelfth valve 204 are opened and the first extra compressor 122 of the evaporated gas that has been discharged from the storage tank T and then passed through the evaporative gas heat exchanger 110 is closed, And the evaporative gas passing through the first extra cooler 132 and the evaporative gas passing through the second extra compressor 124 and the second extra cooler 134 may be combined and supplied to the fuel consumer 180 . When it is necessary to use the evaporated gas compressed by the first extra compressor 122 and the evaporated gas compressed by the second extra compressor 124 as the refrigerant of the refrigerant heat exchanger 140, Or the thirteenth valve 205 may be opened to operate the system.

The evaporation gas compressed by the first extra compressor 122 is used as the refrigerant in the refrigerant heat exchanger 140 while the refrigerant cycle of the ship of this embodiment is operated in the closed loop and the evaporation gas compressed by the compressor 120 (Hereinafter referred to as a "second closed loop"), the first valve 191, the second valve 191, the second valve 191, The valve 192, the third valve 193, the fourth valve 194, the twelfth valve 204, the fourteenth valve 206 and the fifteenth valve 207 are opened and the sixth valve 196, The ninth valve 201, the tenth valve 202, the eleventh valve 203, and the thirteenth valve 205 drive the system in a closed state.

When the evaporated gas compressed by the first extra compressor 122 after being discharged from the storage tank T is supplied to the recycle line L5, the third valve 193 is closed and the evaporated gas is supplied to the first extra compressor 122 The first extra cooler 132, the fourth valve 194, the twelfth valve 204, the refrigerant heat exchanger 140, the refrigerant decompressor 160, the refrigerant heat exchanger 140, Thereby forming a closed-loop refrigerant cycle in which the refrigerant circulates in the refrigerant circuit 206.

Even when the refrigerant cycle is operated as the second closed loop, nitrogen gas may be used as the refrigerant circulating in the closed loop, as in the case of operating as the first closed loop.

Further, even when the refrigerant cycle is operated as the second closed loop, only the evaporated gas circulating in the closed loop is used as the refrigerant in the refrigerant heat exchanger 140, as in the case of operating as the first closed loop, 120 is not introduced into the refrigerant cycle, and is supplied to the fuel consumer 180 or is re-liquefied along the return line L3. Therefore, the evaporation gas at a constant flow rate is circulated to the refrigerant in the refrigerant heat exchanger 140 irrespective of the amount of resolidification or the amount of evaporation gas required by the fuel demanding unit 180.

The operation of the refrigerant cycle as the second closed loop is suitable when the amount demanded in the fuel consumer site 180 is slightly smaller and the amount of the evaporative gas to be re-liquefied is relatively small.

The flow of the evaporative gas in the case where the refrigerant cycle of the ship of this embodiment is operated as the second closed loop will be described as follows.

The evaporated gas discharged from the storage tank T is compressed by the compressor 120 after being passed through the evaporative gas heat exchanger 110 and cooled by the cooler 130 and a part thereof is sent to the fuel consumer 180, And the remaining portion is sent to the evaporation gas heat exchanger 110 along the return line L3. The evaporated gas sent to the evaporation gas heat exchanger 110 along the return line L3 is heat-exchanged with the evaporated gas discharged from the storage tank T and is then cooled in the refrigerant heat exchanger 140 to be further cooled.

The evaporated gas cooled by the evaporative gas heat exchanger (110) and the refrigerant heat exchanger (140) is expanded by the first decompressor (150) to partially or totally re-liquefy. In the case where the ship of this embodiment does not include the gas-liquid separator 170, the evaporated gas partially or totally re-liquefied is directly sent to the storage tank T. When the ship of this embodiment includes the gas-liquid separator 170 The evaporated gas partially or totally re-liquefied is sent to the gas-liquid separator 170. The gas separated by the gas-liquid separator 170 is combined with the evaporated gas discharged from the storage tank T and sent to the evaporation gas heat exchanger 110. The liquid separated by the gas-liquid separator 170 flows into the storage tank T).

On the other hand, the evaporated gas circulating in the refrigerant cycle is compressed by the first extra compressor 122, cooled by the first extra cooler 132, and then passed through the twelfth valve 204 to the refrigerant heat exchanger 140 . The evaporated gas that has passed through the first extra compressor 122 and the first extra cooler 132 and then sent to the refrigerant heat exchanger 140 is firstly heat-exchanged and cooled by the refrigerant heat exchanger 140, ), And is expanded and cooled by a second order. The evaporated gas that has passed through the refrigerant decompressor 160 is again sent to the refrigerant heat exchanger 140. The evaporated gas is supplied to the refrigerant heat exchanger 140 along the return line L3 after passing through the evaporating gas heat exchanger 110, gas; And the evaporation gas compressed by the first extra compressor 122 and then supplied to the refrigerant heat exchanger 140 along the recycle line L5. The evaporated gas used as the refrigerant in the refrigerant heat exchanger 140 after passing through the refrigerant decompressor 160 is sent to the first extra compressor 122 again through the fourteenth valve 206 and repeats the above- do.

The first valve 191, the second valve 192, and the fourteenth valve 206 (see FIG. 2), when the compressor 120 or the cooler 130 fails while the refrigerant cycle of the ship of this embodiment is operated as the second closed loop, The third valve 193 and the sixth valve 196 are opened to allow the evaporated gas that has been discharged from the storage tank T and then passed through the evaporative gas heat exchanger 110 to flow through the third valve 193, The fuel is supplied to the fuel consumer 180 through the first extra compressor 122, the first extra cooler 132, the fourth valve 194, the sixth valve 196, and the fifteenth valve 207. When it is necessary to use the evaporated gas compressed by the first extra compressor 122 as the refrigerant of the refrigerant heat exchanger 140, the ninth valve 201 and the twelfth valve 204 are opened, The valve 204 and the fourteenth valve 206 may be opened to operate the system.

While the refrigerant cycle of the ship of this embodiment is operated as a closed loop, the evaporated gas compressed by the first extra compressor 122 and the evaporated gas compressed by the second extra compressor 124 are supplied to the refrigerant heat exchanger 140, The first valve 191 and the second valve 182 are connected to each other so that the evaporated gas compressed by the compressor 120 is sent to the fuel consumer 180 or is re-liquefied The second valve 192, the fourth valve 194, the ninth valve 201, the eleventh valve 203, the twelfth valve 204, the thirteenth valve 205, the fourteenth valve 206, The fifteenth valve 207 is opened and the third valve 193, the sixth valve 196 and the tenth valve 202 are driven in a closed state.

When the evaporated gas compressed by the first extra compressor 122 and the evaporated gas compressed by the second extra compressor 124 after being discharged from the storage tank T are supplied to the recycle line L5, 201 are closed and the evaporative gas passed through the first extra compressor 122 and the first extra cooler 132 along the second supply line L2 and the evaporative gas passing through the second extra compressor And the evaporation gas that has passed through the second extra cooler 134 are fed to the refrigerant heat exchanger 140 along the recycle line L5 and the refrigerant supplied to the refrigerant heat exchanger 140 is cooled by the refrigerant After passing through the pressure reducing device 160 and again the refrigerant heat exchanger 140, is branched again into two flows to be sent to the first extra compressor 122 or the second extra compressor 124 to form a closed loop refrigerant cycle .

Even when the refrigerant cycle is operated as the third closed loop, nitrogen gas may be used as the refrigerant circulating in the closed loop, as in the case of operating as the first closed loop.

Also, even when the refrigerant cycle is operated as the third closed loop, only the evaporated gas circulating in the closed loop is used as the refrigerant in the refrigerant heat exchanger 140, as in the case of operating as the first closed loop, 120 is not introduced into the refrigerant cycle, and is supplied to the fuel consumer 180 or is re-liquefied along the return line L3. Therefore, the evaporation gas at a constant flow rate is circulated to the refrigerant in the refrigerant heat exchanger 140 irrespective of the amount of resolidification or the amount of evaporation gas required by the fuel demanding unit 180.

The operation of the refrigerant cycle as the third closed loop is suitable when the quantity demanded by the fuel consumer 180 is small and the amount of evaporative gas to be liquefied is large.

The flow of the evaporative gas in the case where the refrigerant cycle of the ship of this embodiment is operated as the third closed loop will be described as follows.

The evaporated gas discharged from the storage tank T is compressed by the compressor 120 after being passed through the evaporative gas heat exchanger 110 and cooled by the cooler 130 and a part thereof is sent to the fuel consumer 180, And the remaining portion is sent to the evaporation gas heat exchanger 110 along the return line L3. The evaporated gas sent to the evaporation gas heat exchanger 110 along the return line L3 is heat-exchanged with the evaporated gas discharged from the storage tank T and is then cooled in the refrigerant heat exchanger 140 to be further cooled.

The evaporated gas cooled by the evaporative gas heat exchanger (110) and the refrigerant heat exchanger (140) is expanded by the first decompressor (150) to partially or totally re-liquefy. In the case where the ship of this embodiment does not include the gas-liquid separator 170, the evaporated gas partially or totally re-liquefied is directly sent to the storage tank T. When the ship of this embodiment includes the gas-liquid separator 170 The evaporated gas partially or totally re-liquefied is sent to the gas-liquid separator 170. The gas separated by the gas-liquid separator 170 is combined with the evaporated gas discharged from the storage tank T and sent to the evaporation gas heat exchanger 110. The liquid separated by the gas-liquid separator 170 flows into the storage tank T).

On the other hand, some of the evaporated gas circulating the refrigerant cycle is compressed by the first extra compressor 122, cooled by the first extra cooler 132 and sent to the recycle line L5, Compressed by the compressor 124, cooled by the second extra cooler 134, and sent to the recycle line L5. The evaporated gas compressed by the first extra compressor 122 and the evaporated gas compressed by the second extra compressor 124 are combined in the recycle line L5 and sent to the refrigerant heat exchanger 140. The recycle line L5 The evaporated gas sent to the refrigerant heat exchanger 140 is firstly heat-exchanged in the refrigerant heat exchanger 140 and cooled. The refrigerant is then sent to the refrigerant depressurization device 160 and is expanded and cooled.

The evaporated gas that has passed through the refrigerant decompressor 160 is again sent to the refrigerant heat exchanger 140. The evaporated gas is supplied to the refrigerant heat exchanger 140 along the return line L3 after passing through the evaporating gas heat exchanger 110, gas; And the evaporation gas supplied to the refrigerant heat exchanger 140 along the recycle line L5. The evaporated gas used as the refrigerant in the refrigerant heat exchanger 140 after passing through the refrigerant decompressor 160 is further divided into two and sent to the first extra compressor 122 or the second extra compressor 124, Repeat a series of steps.

If the compressor 120 or the cooler 130 fails during the operation of the third closed loop of the refrigerant cycle of the present embodiment, for example, the first valve 191 and the second valve 192 are closed, The sixth valve 196 and the ninth valve 201 are opened to allow the combined flow of the evaporated gas compressed by the first extra compressor 122 and the evaporated gas compressed by the second extra compressor 124, May be operated in such a manner that the refrigerant is sent to the fuel consumer 180 and the other part is re-liquefied along the return line L3 and the remaining part is sent to the refrigerant heat exchanger 140 as a refrigerant.

The first valve 191, the second valve 192, the third valve 193, the fourth valve 194, the sixth valve 196, the second valve 193, The ninth valve 201, the tenth valve 202, the eleventh valve 203, the twelfth valve 204 and the fifteenth valve 207 are opened and the thirteenth valve 205 and the fourteenth valve 206 ) Is closed.

When the refrigerant cycle is operated as a closed loop, the evaporating gas circulating the refrigerant cycle is separated from the evaporating gas that is sent to the fuel consumer 180 or is subjected to the re-liquefaction process along the return line L3. On the other hand, when the refrigerant cycle is opened, the evaporation gas compressed by the compressor 120, the evaporation gas compressed by the first extra compressor 122, and the evaporation gas compressed by the second extra compressor 124 Is used as a refrigerant in the refrigerant heat exchanger 140, is sent to the fuel consumer 180, or is re-liquefied along the return line L3.

Therefore, when the refrigerant cycle is operated as an open loop, the flow rate of the refrigerant to the refrigerant heat exchanger 140 can be flexibly controlled in consideration of the amount of re-liquefaction and the amount of evaporation gas required at the fuel consumption site 180. Particularly, when the amount of evaporation gas required in the fuel demanding area 180 is small, increasing the flow rate of the refrigerant to the refrigerant heat exchanger 140 can increase the re-liquefaction efficiency and the liquefaction amount.

Compared with the third closed loop described above, for example, when the refrigerant cycle is operated as the third closed loop, the evaporated gas exceeding the capacity of the first extra compressor 122 and the second extra compressor 124 is supplied to the refrigerant heat exchanger When the refrigerant cycle is operated as an open loop, the evaporated gas at a flow rate exceeding the capacity of the first extra compressor 122 and the second extra compressor 124 is supplied to the refrigerant heat exchanger 140 Can supply.

The flow of the evaporative gas in the case where the refrigerant cycle of the ship of this embodiment is operated as an open loop will be described as follows.

The evaporated gas discharged from the storage tank T is branched into three flows after passing through the evaporative gas heat exchanger 110 and partly sent to the first feed line L1 and the other part is fed to the second feed line L1 L2, and the remaining part is sent to the third supply line L6.

After passing through the first valve 191, the compressor 120, the cooler 130 and the second valve 192, the evaporated gas sent to the first supply line L1 is partially returned to the sixth valve 196, 12 valve 204 to the refrigerant heat exchanger 140, and the other part branches back into two flows. One of the evaporated gases branched to the two flows is sent to the fuel consumer 180 and the remainder is sent to the evaporative gas heat exchanger 110 along the return line L3.

The evaporated gas sent to the second supply line L2 passes through the third valve 193, the first extra compressor 122, the first extra cooler 132 and the fourth valve 194, 12 valve 204 to the refrigerant heat exchanger 140 and the other portion is sent to the first supply line L1 through the sixth valve 196 and then branches to two flows. One of the evaporated gases branched to the two flows is sent to the fuel consumer 180 and the remaining stream is sent to the evaporative gas heat exchanger 110 along the return line L3.

The evaporated gas sent to the third supply line L6 passes through the tenth valve 202, the second extra compressor 124, the second extra cooler 134 and the eleventh valve 203, Heat exchanger 140 and the other part passes through the twelfth valve 204 and the sixth valve 196 to the first supply line L1 and then branches to two flows. One of the evaporated gases branched to the two flows is sent to the fuel consumer 180 and the remaining stream is sent to the evaporative gas heat exchanger 110 along the return line L3.

The evaporation gas compressed by the compressor 120, the evaporation gas compressed by the first redundant compressor 122, and the evaporated gas compressed by the second redundant compressor 124 have been separately described for convenience of explanation The evaporation gas compressed by the compressor 120, the evaporation gas compressed by the first extra compressor 122, and the evaporation gas compressed by the second extra compressor 124 do not flow separately, And is supplied to the refrigerant heat exchanger 140, the fuel consumer 180, or the evaporative gas heat exchanger 110. That is, a recirculation line L5 for sending the evaporation gas to the refrigerant heat exchanger 140, a first supply line L1 for sending the evaporation gas to the fuel consumer 180, and a returning evaporation gas to the evaporation gas heat exchanger 110 In the line L3, the evaporation gas compressed by the compressor 120, the evaporation gas compressed by the first extra compressor 122, and the evaporation gas compressed by the second extra compressor 124 are mixed and flowed.

The evaporated gas sent to the refrigerant heat exchanger 140 along the recirculation line L5 is firstly heat-exchanged by the refrigerant heat exchanger 140 to be cooled, expanded by the refrigerant depressurizing device 160 to be secondarily expanded, And is supplied to the heat exchanger 140. The evaporated gas supplied to the refrigerant heat exchanger 140 after passing through the refrigerant decompressor 160 passes through the evaporation gas heat exchanger 110 and is supplied to the refrigerant heat exchanger 140 along the return line L3 Is used as a refrigerant for cooling both the evaporation gas and the evaporation gas supplied to the refrigerant heat exchanger (140) along the recycle line (L5).

That is, the evaporated gas used as the refrigerant in the refrigerant heat exchanger 140 is supplied to the refrigerant heat exchanger 140 along the recirculation line L5, is first cooled in the refrigerant heat exchanger 140, 160). ≪ / RTI > The evaporated gas sent from the compressor 120, the first extra compressor 122, or the second extra compressor 124 to the refrigerant heat exchanger 140 along the recycle line L5 flows through the refrigerant decompressor 160 And the evaporated gas that has passed through is firstly cooled by the refrigerant.

The evaporated gas used as a refrigerant in the refrigerant heat exchanger 140 after passing through the refrigerant decompressor 160 is sent to the first supply line L1 through the ninth valve 201 to be discharged from the storage tank T And is then merged with the evaporated gas passing through the evaporative gas heat exchanger 110, and the above-described series of processes is repeated.

The evaporation gas sent to the evaporation gas heat exchanger 110 along the return line L3 is first cooled in the evaporation gas heat exchanger 110 and then cooled in the refrigerant heat exchanger 140 to be supplied to the first decompressor 150 to partially or totally re-liquefy.

In the case where the ship of this embodiment does not include the gas-liquid separator 170, the evaporated gas partially or totally re-liquefied is directly sent to the storage tank T. When the ship of this embodiment includes the gas-liquid separator 170 The evaporated gas partially or totally re-liquefied is sent to the gas-liquid separator 170. The gas separated by the gas-liquid separator 170 is combined with the evaporated gas discharged from the storage tank T and sent to the evaporation gas heat exchanger 110. The liquid separated by the gas-liquid separator 170 flows into the storage tank T).

When the compressor (120) or the cooler (130) fails during the operation of the refrigerant cycle of the ship of this embodiment, the first valve (191) and the second valve (192) are closed and the first extra compressor 122 and the second redundant compressor 124 alone to operate the open-loop refrigerant cycle.

When the refrigerant cycle of the ship of this embodiment is operated as an open loop and the liquefied gas stored in the storage tank T is liquefied natural gas and the fuel demanding place 180 is the X-DF engine and includes the gas-liquid separator 170 , The temperature and pressure of the fluid at each point will be described as an example.

The evaporated gas discharged from the storage tank T and the evaporated gas separated by the gas-liquid separator 170 are combined and the evaporated gas at the point A supplied to the evaporated gas heat exchanger 110 is cooled to approximately -127 ° C, And the evaporation gas at point B after the evaporation gas at about -127 DEG C, 1.060 bara, is heat exchanged at about 43 DEG C, 37 bara with the evaporation gas at the evaporation gas heat exchanger 110, is about 26 DEG C, 0.96 It can be bara.

Further, when the evaporation gas at about 26 DEG C, 0.96 bara is mixed with the evaporation gas having passed through the refrigerant decompressor 160 and passed through the refrigerant heat exchanger 140 at about 13 DEG C and 0.96 bara, The evaporation gas may be approximately 17 캜, 0.96 bara.

The evaporation gas, which is approximately 17 DEG C, 0.96 bara, branches to three, one stream is compressed by the compressor 120, then cooled by the cooler 130, and the other stream is compressed by the first extra compressor 122 And the remaining stream is compressed by the second extra compressor 124 and then cooled by the second extra cooler 134 so that the compressor 120 and the cooler 130 are cooled by the first extra cooler 132, Flow through; A flow through the first extra compressor (122) and the first extra cooler (132); And the flow passing through the second extra compressor 124 and the second extra cooler 134 are combined streams, the evaporation gas at the point D and the evaporation gas at the point H can be approximately 43 ° C. and 37 bara.

The evaporation gas at about 43 캜, the evaporation gas at 37 bara, about -127 캜, 1.060 bara, and the evaporation gas at the E point after heat exchange in the evaporation gas heat exchanger 110 can be about -92 캜, 37 bara The evaporated gas at point F, after the evaporated gas, which is approximately -92 캜, 37 bara, has been cooled in the refrigerant heat exchanger 140, may be approximately -124 캜, 36.60 bara and approximately -124 캜, 36.60 bara of evaporation The evaporated gas at point G, after the gas has been expanded by the first decompressor 150, may be -155 캜, 2.1 bara.

On the other hand, the evaporation gas at point I, which is approximately 43 ° C after the refrigerant heat exchanger 140 has been cooled by the refrigerant heat exchanger 140, may be approximately -47 ° C, 36.70bara and approximately -47 ° C, 36.70bara The evaporation gas at the point J, which is after the evaporation gas of the evaporator 150 has been secondarily cooled by the refrigerant decompressor 160, may be approximately -156 캜, 1.56 bara, and evaporation gas of approximately -156 캜, The evaporation gas at the K point after being used as a refrigerant in the evaporator 140 may be approximately 13 DEG C, 0.96 bara.

The ship of the present embodiment is configured such that the evaporation gas compressed by the compressor 120, the evaporation gas compressed by the first redundant compressor 122, and the evaporative gas compressed by the second redundant compressor 124, Some of the compressed compressed evaporated gas is used only as the refrigerant of the refrigerant heat exchanger 140 and the rest is not used as the refrigerant of the refrigerant heat exchanger 140 and is sent to the fuel demanding place 180 or the return line L3, So that the liquid is subjected to a liquefaction process. Hereinafter, it is referred to as an independent open loop.

As the refrigerant cycle of the ship of this embodiment is operated as an independent open loop, the evaporated gas compressed by the first extra compressor 122 and the evaporated gas compressed by the second extra compressor 124 are supplied to the refrigerant heat exchanger 140 (Hereinafter, referred to as 'first independent open loop') in which the evaporated gas compressed by the compressor 120 is sent to the fuel consumer 180 or is subjected to a re-liquefaction process Then,

The first valve 191, the second valve 192, the third valve 193, the fourth valve 194, the ninth valve 193, The seventh valve 201, the tenth valve 202, the eleventh valve 203, the twelfth valve 204 and the fifteenth valve 207 are opened and the sixth valve 196, the thirteenth valve 205, 14 Valve 206 closes. When the refrigerant cycle is operated as an independent open loop, it is advantageous in that the system can be operated more easily than when the open loop is operated.

The flow of the evaporative gas in the case where the refrigerant cycle of the ship of this embodiment is operated as the first independent open loop will be described as follows.

The evaporated gas discharged from the storage tank T is branched into three flows after passing through the evaporative gas heat exchanger 110 and partly sent to the first supply line L1 and the other part is supplied to the second supply line L2 And the remaining part is sent to the third supply line L6.

The evaporated gas sent to the first supply line L1 passes through the first valve 191, the compressor 120, the cooler 130 and the second valve 192 and then partly sent to the fuel consumer 180 , And the other part is sent to the evaporation gas heat exchanger 110 along the return line L3.

The evaporated gas sent to the second supply line L2 passes through the third valve 193, the first extra compressor 122, the first extra cooler 132 and the fourth valve 194, (204) to the refrigerant heat exchanger (140) along the recirculation line (L5).

The evaporated gas sent to the third supply line L6 passes through the tenth valve 202, the second extra compressor 124, the second extra cooler 134 and the eleventh valve 203, L5) to the refrigerant heat exchanger (140).

The evaporated gas compressed by the first redundant compressor 122 and the evaporated gas compressed by the second redundant compressor 124 are separately described for convenience of explanation, The evaporated gas and the evaporated gas compressed by the second extra compressor 124 are not separated and flow separately but are merged in the recycle line L5 and supplied to the refrigerant heat exchanger 140. [

The evaporated gas sent to the refrigerant heat exchanger 140 along the recirculation line L5 is firstly heat-exchanged by the refrigerant heat exchanger 140 to be cooled, expanded by the refrigerant depressurizing device 160 to be secondarily expanded, An evaporation gas supplied to the heat exchanger 140, passed through the evaporation gas heat exchanger 110, and then supplied to the refrigerant heat exchanger 140 through the return line L3; And the evaporation gas supplied to the refrigerant heat exchanger 140 along the recycle line L5.

The evaporated gas used as a refrigerant in the refrigerant heat exchanger 140 after passing through the refrigerant decompressor 160 is sent to the first supply line L1 through the ninth valve 201 to be discharged from the storage tank T And is then merged with the evaporated gas passing through the evaporative gas heat exchanger 110, and the sequence described above is repeated.

The evaporated gas that has been compressed by the compressor 120 and then sent to the evaporative gas heat exchanger 110 along the return line L3 is first cooled in the evaporative gas heat exchanger 110 and then cooled in the refrigerant heat exchanger 140 to 2 Cooled by the car, and then expanded by the first decompressor 150 to partially or totally re-liquefy.

In the case where the ship of this embodiment does not include the gas-liquid separator 170, the evaporated gas partially or totally re-liquefied is directly sent to the storage tank T. When the ship of this embodiment includes the gas-liquid separator 170 The evaporated gas partially or totally re-liquefied is sent to the gas-liquid separator 170. The gas separated by the gas-liquid separator 170 is combined with the evaporated gas discharged from the storage tank T and sent to the evaporation gas heat exchanger 110. The liquid separated by the gas-liquid separator 170 flows into the storage tank T).

The first valve 191 and the second valve 192 are closed while the compressor 120 or the cooler 130 is broken while the refrigerant cycle of the ship of this embodiment is being operated as the first independent open loop, The first valve 191 and the second valve 192 may be opened to allow the first extra compressor 122 and the second extra compressor 124 to operate the open loop refrigerant cycle. The valve 201, the tenth valve 202 and the twelfth valve 204 are closed and the sixth valve 196 and the thirteenth valve 205 are opened so that the evaporation gas compressed by the first extra compressor 122 May be sent to the fuel consumer 180 or subjected to a re-liquefaction process, and the evaporated gas compressed by the second extra compressor 124 may circulate the refrigerant cycle in the closed loop.

If the refrigerant cycle of the ship of this embodiment is operated as an independent open loop and the evaporated gas compressed by the second extra compressor 124 is used as the refrigerant of the refrigerant heat exchanger 140, The first valve 191, the second valve 192, the second valve 192, and the second valve 192 are connected to the fuel consuming station 180, The third valve 193, the fourth valve 194, the sixth valve 196, the ninth valve 201, the tenth valve 202, the eleventh valve 203 and the fifteenth valve 207 are opened The twelfth valve 204, the thirteenth valve 205, and the fourteenth valve 206 are closed and the system can be operated.

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.

100a, 100b, 120: compressors 200a, 200b, 110: evaporation gas heat exchanger
300a, 300b: refrigerant circulation units 310a, 310b: refrigerant compressor
320a, 320b, 130: cooler 330a, 330b, 160: refrigerant pressure reducing device
400a, 400b, 191 to 198, 201 to 207: valves
500a, 500b, 140: refrigerant heat exchanger 600a, 600b, 150: first decompression device
700a, 700b, 170: gas-liquid separator 800a, 800b: second decompression device
122: first extra compressor 124: second extra compressor
132: first extra cooler 134: second extra cooler
180: Fuel Consumption

Claims (9)

A ship comprising a storage tank for storing liquefied gas,
An evaporating gas heat exchanger installed downstream of the storage tank for cooling the evaporated gas discharged from the storage tank as a refrigerant by heat exchange with compressed evaporated gas (hereinafter, referred to as 'first fluid');
A compressor installed downstream of the evaporating gas heat exchanger for compressing a part of the evaporated gas discharged from the storage tank;
A first extra compressor installed in parallel with the compressor downstream of the evaporative gas heat exchanger to compress another portion of the evaporative gas discharged from the storage tank;
A second redundant compressor installed downstream of the evaporative gas heat exchanger in parallel with the compressor and the first redundant compressor to compress a remaining portion of the evaporative gas discharged from the storage tank;
A refrigerant heat exchanger for additionally cooling the first fluid cooled by the evaporation gas heat exchanger;
(Hereinafter referred to as " second fluid ") that is sent to the refrigerant heat exchanger (hereinafter, referred to as a " second fluid ") to expand the second fluid cooled by the refrigerant heat exchanger to the refrigerant heat exchanger ;
A first decompression device for expanding the first fluid cooled by the evaporation gas heat exchanger and the refrigerant heat exchanger;
A sixth valve installed on a line communicating an evaporated gas compressed by the compressor and an evaporated gas compressed by the first extra compressor; And
And a twelfth valve installed on a line communicating an evaporated gas compressed by the first extra compressor and an evaporated gas compressed by the second extra compressor,
Wherein the refrigerant heat exchanger uses the evaporation gas that has passed through the refrigerant decompression device as a refrigerant to cool both the first fluid and the second fluid by heat exchange,
The first fluid comprising: an evaporation gas compressed by the compressor; An evaporation gas compressed by said first extra compressor; A flow combining the evaporated gas compressed by the compressor and the evaporated gas compressed by the first extra compressor; And a flow of the evaporated gas compressed by the compressor, the evaporated gas compressed by the first extra compressor, and the evaporated gas compressed by the second extra compressor; , ≪ / RTI >
Said second fluid comprising: an evaporative gas compressed by said first extra compressor; An evaporation gas compressed by said second extra compressor; A flow combining the evaporation gas compressed by the first extra compressor and the evaporation gas compressed by the second extra compressor; And a flow of the evaporated gas compressed by the compressor, the evaporated gas compressed by the first extra compressor, and the evaporated gas compressed by the second extra compressor; , ≪ / RTI >
The sixth valve and the twelfth valve include: evaporative gas compressed by the compressor; An evaporation gas compressed by said first extra compressor; And an evaporation gas compressed by the second extra compressor, are opened or closed to join or separate. The method according to claim 1,
Wherein the evaporated gas used as the refrigerant of the refrigerant heat exchanger after passing through the refrigerant pressure reducing device is merged with the evaporated gas that has passed through the evaporative gas heat exchanger after being discharged from the storage tank. The method according to claim 1,
The evaporated gas used as the refrigerant in the refrigerant heat exchanger after being compressed by the first extra compressor is again sent to the first extra compressor to be supplied to the first extra compressor, the refrigerant heat exchanger, the refrigerant decompressor, Wherein the refrigerant cycle forms a closed loop refrigerant cycle. The method according to claim 1,
The evaporated gas used as the refrigerant of the refrigerant heat exchanger after being compressed by the second extra compressor is again sent to the second extra compressor to be supplied to the second extra compressor, the refrigerant heat exchanger, the refrigerant decompressor, Wherein the refrigerant cycle forms a closed loop refrigerant cycle. The method according to claim 1,
The evaporated gas compressed by the first extra compressor and the evaporated gas compressed by the second extra compressor are combined and supplied to the refrigerant heat exchanger, and the evaporated gas supplied to the refrigerant heat exchanger is re- Wherein the refrigerant cycle is branched into two flows after passing through the refrigerant heat exchanger to be sent to the first extra compressor or the second extra compressor. The evaporating gas discharged from the liquefied gas storage tank is branched into three, the evaporated gas of the three branched streams is compressed by the compressor, the first extra compressor, or the second extra compressor,
At least one of the evaporation gas compressed by the compressor, the evaporation gas compressed by the first extra compressor, and the evaporation gas compressed by the second extra compressor is sent to the fuel consumer, (Hereinafter, referred to as 'return evaporated gas'), recycled (hereinafter referred to as 'recirculated evaporated gas'),
Wherein the return evaporated gas is heat-exchanged with the evaporated gas discharged from the storage tank and is then further heat-exchanged with the recycled evaporated gas to be further cooled,
The recirculated evaporation gas is heat exchanged with the return evaporation gas after being cooled and expanded,
A sixth valve installed on a line connecting the downstream line of the compressor and the downstream line of the first extra compressor; And
A twelfth valve installed on a line connecting the first extra compressor downstream line and the second extra compressor downstream line,
An evaporating gas compressed by the compressor; An evaporation gas compressed by said first extra compressor; And the evaporation gas compressed by the second extra compressor are joined or separated. The method according to any one of claims 1 to 5,
Wherein each of the compressor, the first extra compressor, and the second extra compressor is designed to have a capacity of 1/3 of the total capacity necessary to supply evaporative gas discharged from the storage tank to the fuel consumer and to re-liquefy it. delete delete

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