KR20180076940A - Fuel supply system for ship - Google Patents

Abstract

Disclosed is a fuel supply system for a ship, capable of replacing a multistage compression unit with a two-stage compression unit. According to the present invention, the fuel supply system for a ship comprises: a storage tank to store liquefied gas; an additional compressor to compress evaporation gas discharged from the storage tank; a multistage compression unit to compress the evaporation gas compressed by the additional compressor through multiple stages; a heat exchanger to heat-exchange and cool the evaporation gas compressed by the multistage compression unit by using evaporation gas discharged from the storage tank; and an expansion means to expand a fluid cooled by the heat exchanger. The multistage compression unit comprises two stages of first and second compressors, a part or all of the evaporation gas compressed by the multistage compression unit is sent to a high pressure engine, and the excess evaporation gas not used in the high pressure engine among the evaporation gas compressed by the multistage compression unit is sent to the heat exchanger.

Description

[0001] FUEL SUPPLY SYSTEM FOR SHIP [0002]

The present invention relates to a fuel supply system for a ship capable of optimizing a system for compressing fuel supplied to an engine to high pressure.

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 which can be obtained by cooling methane-based natural gas to about -163 ° C and liquefying it, and has a volume of about 1/600 as compared with 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 -163 ° C at normal pressure, liquefied natural gas is susceptible to temperature change 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, there are gas-fuel engines such as DFDE, ME-GI engine and X-DF engine which can be used as natural gas among the engines used in ships.

DFDE is used for power generation and consists of four strokes. (Otto Cycle) which injects natural gas having a pressure of about 6.5 bara, which is relatively low pressure, into the combustion air inlet and compresses the piston as it rises.

The ME-GI engine is used for propulsion and consists of two strokes. It adopts a diesel cycle in which high pressure natural gas near 300 bara is injected directly to the combustion chamber near the piston top dead center.

The X-DF engine is used for propulsion and consists of two strokes. It uses 16 bara of medium pressure natural gas as fuel and adopts autocycle.

An object of the present invention is to provide a fuel supply system for a ship in which a multi-stage compression section for compressing natural gas at a pressure required by a high-pressure engine is optimized to be composed of two stages.

According to an aspect of the present invention, there is provided a liquid storage tank for storing liquefied gas. An additional compressor for compressing the evaporated gas discharged from the storage tank; A multi-stage compression unit for multi-stage compressing the evaporated gas compressed by the additional compressor; A heat exchanger for exchanging heat between the evaporated gas discharged from the storage tank and the evaporated gas compressed by the multi-stage compressing unit; And a expansion means for expanding the fluid cooled by the heat exchanger, wherein the multi-stage compression section is constituted by two stages of a first compressor and a second compressor, and a part of the evaporation gas compressed by the multi- All of which is sent to the high-pressure engine, and the surplus evaporated gas not used in the high-pressure engine among the evaporated gases compressed by the multi-stage compressing section is sent to the heat exchanger.

The fuel supply system of the ship may further include a gas-liquid separator provided at a downstream end of the expansion means for separating the liquefied gas re-liquefied and the gaseous evaporative gas.

The fuel supply system of the ship includes a pump for pressurizing the liquefied gas in the storage tank; And a vaporizer for vaporizing the liquefied gas pressurized by the pump, and the gas vaporized by the vaporizer can be supplied to the fuel of the high-pressure engine.

The evaporated gas separated by the gas-liquid separator may be combined with the evaporated gas discharged from the storage tank and used as a refrigerant in the heat exchanger.

The additional compressor may be a compressor that compresses the fluid to a lower pressure than the first compressor and the second compressor.

The evaporated gas compressed by the further compressor may be at 45 [deg.] C, 6.5 bara.

The evaporated gas compressed by the additional compressor can be partly branched and supplied to the low-pressure engine.

The evaporated gas sent to the heat exchanger after being compressed by the multi-stage compressing unit may be 43 ° C. and 300 bara.

The high-pressure engine can use a gas of 45 ° C, 300 bara as fuel.

According to another aspect of the present invention, there is provided a storage tank for storing liquefied gas. A multi-stage compression unit for multi-stage compressing the evaporated gas discharged from the storage tank; A heat exchanger for exchanging heat between the evaporated gas discharged from the storage tank and the evaporated gas compressed by the multi-stage compressing unit; And a expansion means for expanding the fluid cooled by the heat exchanger, wherein the multi-stage compression section is constituted by two stages of a first compressor and a second compressor, and a part of the evaporation gas compressed by the multi- And the surplus evaporation gas not used in the high-pressure engine is sent to the heat exchanger, and the pressure of the evaporation gas discharged from the storage tank is 6.6 bara A fuel supply system for a ship is provided.

The storage tank may be a Type C tank composed of components including high manganese steel.

The fuel supply system of the ship may further include a gas-liquid separator provided at the downstream end of the expansion means to separate the liquefied gas re-liquefied and the gaseous vaporized gas, and the gas-liquid separator stores the fluid until 6.7 bara Can be discharged.

The gas-liquid separator may be a Type C gas-liquid separator comprised of components comprising high manganese steel.

The evaporated gas separated by the gas-liquid separator may be combined with the evaporated gas discharged from the storage tank and used as a refrigerant in the heat exchanger.

The fuel supply system of the ship may further include a heater installed between the heat exchanger and the multi-stage compression unit.

The evaporated gas heated by the heater can be partially branched and supplied to the low-pressure engine.

The evaporated gas heated by the heater may be at 45 [deg.] C and 6.5 bara.

The evaporated gas sent to the heat exchanger after being compressed by the multi-stage compression unit may be in a state of 43 ° C and 300 bara.

The high-pressure engine can use a gas of 45 ° C, 300 bara as fuel.

The fuel supply system of the ship includes a pump for pressurizing the liquefied gas in the storage tank; And a vaporizer for vaporizing the liquefied gas pressurized by the pump, wherein the gas vaporized by the vaporizer can be supplied to the fuel of the high-pressure engine.

According to the present invention, since the multi-stage compression unit having five stages in the related art can be configured in two stages, it is possible to reduce the cost for installing the equipment and the cost for operating the equipment.

1 is a schematic view of a fuel supply system for a ship according to a first preferred embodiment of the present invention.
2 is a schematic view of a fuel supply system for a ship according to a second preferred embodiment of the present invention.

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 fuel supply system of the present invention can be applied to various applications such as a ship equipped with an engine using natural gas as a 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.

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 of a fuel supply system for a ship according to a first preferred embodiment of the present invention. The first embodiment shown in Fig. 1 can be preferably applied particularly to a liquefied natural gas carrier.

1, the fuel supply system for a ship of the present embodiment includes a storage tank T, a heat exchanger 100, an additional compressor 900, a multi-stage compression unit 200, and an expansion means 300 .

The storage tank T of the present embodiment has a sealing and an insulating barrier so as to store liquefied natural gas or the like in a cryogenic state but can not completely block the heat transmitted from the outside, The evaporation gas in the storage tank T is discharged in order to prevent excessive rise of the pressure due to the evaporation gas and to maintain an appropriate level of internal pressure . The evaporation gas (point A1 in FIG. 1) discharged from the storage tank T of this embodiment can be approximately -130 DEG C, 1.06 bara.

 In the heat exchanger 100 of the present embodiment, the evaporation gas discharged from the storage tank T is used as a refrigerant, and the evaporation gas compressed by the multi-stage compression unit 200 is heat-exchanged to cool the evaporation gas. The evaporation gas (point B1 in FIG. 1) used as a refrigerant in the heat exchanger 100 after being discharged from the storage tank T may be approximately 7.degree. C., 1.04 bara.

The additional compressor 900 of the present embodiment compresses the evaporated gas used as the refrigerant in the heat exchanger 100 after being discharged from the storage tank T. The additional compressor 900 of the present embodiment may be a compressor that compresses the fluid at a lower pressure than that of the first compressor 210 and the second compressor 220 included in the multi-

The evaporated gas (point C1 in FIG. 1) compressed by the additional compressor 900 of this embodiment may be approximately 45 DEG C, 6.5 bara.

According to the present embodiment, the evaporated gas compressed by the additional compressor 900 can be partially branched and supplied to the low-pressure engine, and the remainder can be supplied to the multi-stage compression section 200. The low- It may be an engine that uses 6.5 bara of gas as fuel.

The multi-stage compression section 200 of the present embodiment compresses the evaporation gas used as the refrigerant in the heat exchanger 100 in multiple stages up to the required pressure of the high-pressure engine after being discharged from the storage tank T. The multi-stage compression unit 200 of the present embodiment includes a first compressor 210 and a second compressor 220, and is configured in two stages unlike the conventional one which is constituted by five stages.

A part or all of the evaporated gas compressed by the multi-stage compression section 200 of this embodiment is sent to the high-pressure engine, and the excess evaporated gas not used in the high-pressure engine among the evaporated gases compressed by the multi- And then sent to the machine 100 for re-liquefaction. The evaporation gas compressed by the multi-stage compression section 200 and then sent to the heat exchanger 100 can be approximately 43 ° C. and 300 bara (D1 point in FIG. 1), and the high-pressure engine has approximately 45 ° C., As an engine.

The expansion means 300 of the present embodiment expands the cooled fluid after being compressed by the multi-stage compression section 200 and then heat-exchanged with the refrigerant in the evaporation gas discharged from the storage tank T in the heat exchanger 100. The expansion means (300) of this embodiment can be an expansion valve, such as a Row-Thomson valve.

Some or all of the evaporation gas that has undergone the compression process by the multi-stage compression unit 200, the cooling process by the heat exchanger 100, and the expansion process by the expansion unit 300 is re-liquefied.

The fuel supply system of the present embodiment of the present invention may further include a gas-liquid separator 400 disposed at the downstream end of the expansion means 300 to separate the liquefied gas and the gas-phase evaporation gas.

A first valve (V1) for controlling the flow rate and opening and closing of the fluid may be provided on the line through which the evaporated gas separated by the gas-liquid separator (400) of this embodiment is discharged. A second valve V2 for controlling the flow rate and opening / closing of the fluid may be installed on the line through which the liquefied gas is discharged.

The evaporated gas separated by the gas-liquid separator 400 may be combined with the evaporated gas discharged from the storage tank T and used as a refrigerant in the heat exchanger 100, Can be returned to the storage tank (T). The liquefied gas (point E1 in Fig. 1) returned to the storage tank T after being separated by the gas-liquid separator 400 may be -161 캜, 1.06 bara.

 The fuel supply system of the ship of the present embodiment may further include a pump 500 for pressurizing the liquefied gas inside the storage tank T and a vaporizer 600 for vaporizing the liquefied gas pressurized by the pump 500 have.

The pump 500 and the vaporizer 600 of the present embodiment vaporize the liquefied gas in the storage tank T and supply it to the engine when the evaporation gas inside the storage tank T does not satisfy the amount required by the engine . According to the present embodiment, since the liquefied gas is first compressed and vaporized instead of gasifying the liquefied gas after vaporizing it, a pump 500 that is relatively inexpensive and low in operation cost is used without using a compressor for pressurizing the gas ) Is economical.

On the line through which the liquefied gas discharged from the storage tank T passes through the pump 500 and the vaporizer 600 and is sent to the low-pressure engine or the high-pressure engine, the pressure and temperature conditions required by the low- A pressure reducing device, a pressurizing device, and a heater may be provided.

2 is a schematic view of a fuel supply system for a ship according to a second preferred embodiment of the present invention. The second embodiment shown in Fig. 2 can be preferably applied particularly to a ship using liquefied natural gas as a propulsion fuel for a ship.

The fuel supply system of the ship according to the second embodiment shown in Fig. 2 does not include the additional compressor 900, and the fuel supply system of the ship of the first embodiment shown in Fig. There is a difference in that the pressure of the evaporating gas is approximately 6.6 bara. In the following, the difference is mainly described. A detailed description of the same components as those of the fuel supply system of the ship of the first embodiment will be omitted.

2, the fuel supply system of the present embodiment includes a storage tank T, a heat exchanger 100, a multi-stage compression unit 200, and an expansion means 300 as in the first embodiment do. However, the fuel supply system of the present embodiment does not include the additional compressor 900, unlike the first embodiment.

Unlike the first embodiment, the storage tank T of this embodiment stores and discharges the evaporation gas to about 6.6 bara. The storage tank T of the present embodiment may be a Type C tank made of a component containing high manganese steel. The evaporation gas (point A2 in FIG. 2) discharged from the storage tank T may be approximately -130 DEG C, 6.6 bara.

The heat exchanger 100 of the present embodiment cools the evaporated gas discharged from the storage tank T as a refrigerant by heat exchange with the evaporated gas compressed by the multi-stage compression section 200, as in the first embodiment.

The multi-stage compression section 200 of the present embodiment compresses the evaporation gas used as the refrigerant in the heat exchanger 100 after being discharged from the storage tank T in a multistage manner up to the required pressure of the high-pressure engine as in the first embodiment .

The multistage compressing unit 200 of the present embodiment includes a first compressor 210 and a second compressor 220 as in the first embodiment. Unlike the conventional multistage compressing unit 200 having five stages, The multi-stage compression unit 200 of this embodiment can be configured in two stages because the pressure of the evaporation gas discharged from the storage tank T is approximately 6.6 bara and the pressure of the evaporation gas discharged from the conventional storage tank is approximately Which is higher than 1.06 bara.

The evaporation gas (point B2 in FIG. 2) supplied to the multi-stage compression unit 200 after being discharged from the storage tank T and used as a refrigerant in the heat exchanger 100 is preferably about 45 DEG C and 6.5 bara, The fuel supply system of the ship of the present embodiment may further include a heater 800 installed between the heat exchanger 100 and the multi-stage compression unit 200, in case the temperature of the evaporation gas at the point B1 is low have.

According to the present embodiment, when the evaporator 200 (including the heater 800), which is discharged from the storage tank T and used as a refrigerant in the heat exchanger 100, is used as a refrigerant in the heat exchanger 100, Pressure engine, and the low-pressure engine can be supplied to the multi-stage compression unit 200, and the low-pressure engine can be supplied to the engine using the gas of about 45 [deg.] C and 6.5 bara as fuel Lt; / RTI >

According to the present embodiment, as in the first embodiment, part or all of the evaporative gas compressed by the multi-stage compressing section 200 is sent to the high-pressure engine, and the high-pressure The surplus evaporated gas not used in the engine is sent to the heat exchanger 100 and subjected to a liquefaction process. The evaporation gas (point C2 in FIG. 2) that is compressed by the multi-stage compression section 200 and then sent to the heat exchanger 100 may be approximately 43 ° C. and 300 bara and the high pressure engine may be approximately 45 ° C., As an engine.

The expansion means 300 of the present embodiment is configured such that the evaporated gas discharged from the storage tank T in the heat exchanger 100 after being compressed by the multi-stage compression section 200 is heat- Thereby expanding the fluid. The expansion means (300) of this embodiment can be an expansion valve, such as a Row-Thomson valve.

The evaporation gas, which has undergone the compression process by the multi-stage compression section 200, the cooling process by the heat exchanger 100, and the expansion process by the expansion means 300, Liquefied.

The fuel supply system of the present embodiment may further include a gas-liquid separator 400 disposed at the downstream end of the expansion means 300 to separate the liquefied gas re-liquefied and the gaseous evaporative gas, as in the first embodiment have. However, unlike the first embodiment, the gas-liquid separator 400 of the present embodiment may be a Type C gas-liquid separator composed of components containing high-manganese steel after storing and discharging the fluid to approximately 6.7 bara.

According to the present embodiment, as in the first embodiment, a first valve V1 for controlling the flow rate and opening and closing of the fluid may be provided on the line through which the evaporated gas separated by the gas-liquid separator 400 is discharged, A second valve (V2) may be provided on the line through which the liquefied gas separated by the separator (400) is discharged, for controlling the flow rate and opening / closing of the fluid.

Also, according to the present embodiment, as in the first embodiment, the evaporated gas separated by the gas-liquid separator 400 is combined with the evaporated gas discharged from the storage tank T to be used as a refrigerant in the heat exchanger 100 And the liquefied gas separated by the gas-liquid separator 400 can be returned to the storage tank T. The liquefied gas (point D2 in Fig. 2) returned to the storage tank T after being separated by the gas-liquid separator 400 may be -161 캜, 6.7 bara.

 As in the first embodiment, the fuel supply system of the present embodiment is provided with a pump 500 for pressurizing the liquefied gas in the storage tank T and a vaporizer (for example, a vaporizer for vaporizing the liquefied gas pressurized by the pump 500 600).

The pump 500 and the vaporizer 600 of the present embodiment are configured such that when the evaporation gas inside the storage tank T does not satisfy the amount required by the engine as in the first embodiment, It serves to vaporize the gas and supply it to the engine. According to this embodiment, as in the first embodiment, the liquefied gas is first compressed and then vaporized, instead of gasifying and liquefying the liquefied gas. Therefore, the compressor is not used to press the gas, It is economical to use the pump 500 with a low cost.

On the line through which the liquefied gas discharged from the storage tank T passes through the pump 500 and the vaporizer 600 and is sent to the low-pressure engine or the high-pressure engine, as in the first embodiment, And at least one of a pressure reducing device, a pressurizing device, and a heater for adjusting the temperature condition.

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.

T: Storage tank V1, V2: Valve
100: Heat exchanger 200: Multistage compression unit
210, 220: Compressor 300: Expansion means
400: gas-liquid separator 500: pump
600: vaporizer 800: heater
900: Additional compressors

Claims (20)

A storage tank for storing liquefied gas;
An additional compressor for compressing the evaporated gas discharged from the storage tank;
A multi-stage compression unit for multi-stage compressing the evaporated gas compressed by the additional compressor;
A heat exchanger for exchanging heat between the evaporated gas discharged from the storage tank and the evaporated gas compressed by the multi-stage compressing unit; And
And expansion means for expanding the fluid cooled by the heat exchanger,
Wherein the multi-stage compression section is composed of two stages of a first compressor and a second compressor,
Wherein a part or all of the evaporated gas compressed by the multi-stage compressing section is sent to the high-pressure engine, and the surplus evaporated gas not used in the high-pressure engine among the evaporated gases compressed by the multi-stage compressing section is sent to the heat exchanger Of the fuel supply system. The method according to claim 1,
And a gas-liquid separator provided at the downstream end of the expansion means to separate the liquefied gas re-liquefied and the gaseous evaporative gas. The method according to claim 1,
A pump for pressurizing the liquefied gas in the storage tank; And
And a vaporizer for vaporizing the liquefied gas pressurized by the pump,
Wherein the gas vaporized by the vaporizer is supplied to the fuel of the high-pressure engine. The method of claim 2,
Wherein the evaporated gas separated by the gas-liquid separator is combined with the evaporated gas discharged from the storage tank and used as a refrigerant in the heat exchanger. The method according to any one of claims 1 to 4,
Wherein the additional compressor is a compressor that compresses the fluid to a lower pressure than the first compressor and the second compressor. The method according to any one of claims 1 to 4,
Wherein the evaporated gas compressed by the further compressor is at 45 [deg.] C, 6.5 bara. The method according to any one of claims 1 to 4,
Wherein the evaporated gas compressed by the additional compressor is partly branched and supplied to the low-pressure engine. The method according to any one of claims 1 to 4,
Wherein the evaporated gas that is compressed by the multi-stage compression unit and then sent to the heat exchanger is 43 [deg.] C, 300 bara. The method according to any one of claims 1 to 4,
The high-pressure engine uses a gas of 45 degrees Celsius and 300 bara as fuel. A storage tank for storing liquefied gas;
A multi-stage compression unit for multi-stage compressing the evaporated gas discharged from the storage tank;
A heat exchanger for exchanging heat between the evaporated gas discharged from the storage tank and the evaporated gas compressed by the multi-stage compressing unit; And
And expansion means for expanding the fluid cooled by the heat exchanger,
Wherein the multi-stage compression section is composed of two stages of a first compressor and a second compressor,
Wherein a part or all of the evaporated gas compressed by the multi-stage compressing unit is sent to the high-pressure engine, and the surplus evaporated gas not used in the high-pressure engine among the evaporated gases compressed by the multi-stage compressing unit is sent to the heat exchanger,
Wherein the pressure of the evaporative gas discharged from the storage tank is 6.6 bara. The method of claim 10,
Wherein the storage tank is a Type C tank composed of components comprising high manganese steel. The method of claim 10,
Further comprising a gas-liquid separator provided at the downstream end of the expansion means for separating the re-liquefied liquefied gas from the gaseous vaporized gas,
The gas-liquid separator stores and discharges the fluid up to 6.7 bara. The method of claim 12,
Wherein the gas-liquid separator is a Type C gas-liquid separator composed of components including high manganese steel. The method of claim 12,
Wherein the evaporated gas separated by the gas-liquid separator is combined with the evaporated gas discharged from the storage tank and used as a refrigerant in the heat exchanger. The method of claim 10,
Further comprising a heater installed between the heat exchanger and the multi-stage compression unit. 16. The method of claim 15,
Wherein a portion of the evaporated gas heated by the heater is branched and supplied to the low-pressure engine. 16. The method of claim 15,
Wherein the evaporated gas heated by the heater is at 45 占 폚, 6.5 bara. The method according to any one of claims 10 to 17,
Wherein the evaporated gas which is compressed by the multi-stage compression unit and then sent to the heat exchanger is in a state of 43 ° C, 300 bara. The method according to any one of claims 10 to 17,
The high-pressure engine uses a gas of 45 degrees Celsius and 300 bara as fuel. The method according to any one of claims 10 to 17,
A pump for pressurizing the liquefied gas in the storage tank; And
And a vaporizer for vaporizing the liquefied gas pressurized by the pump,
Wherein the gas vaporized by the vaporizer is supplied to the fuel of the high-pressure engine.

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