KR101767552B1 - Vessels - Google Patents

Abstract

The vessel is started.
The ship includes a compression system for compressing the evaporation gas discharged from the storage tank in multiple stages and supplying it as fuel to the engine. And a vaporization system for vaporizing the liquefied natural gas in the storage tank and supplying the liquefied natural gas to the fuel of the engine, wherein the vaporization system regulates the pressure of the engine front end, The pressure of the storage tank is adjusted, and when the vaporization system is stopped, the pressure of the front end of the engine is adjusted.

Description

Ship {Vessels}

The present invention relates to a storage tank for storing liquefied natural gas and a ship equipped with an engine using natural gas as fuel.

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 and compresses the piston as it rises.

The ME-GI engine consists of two strokes and adopts a diesel cycle in which high pressure natural gas near 300 bar is injected directly to the combustion chamber near the piston's top dead center. In recent years, there is a growing interest in ME-GI engines with better fuel efficiency and propulsion efficiency.

A ship equipped with an engine using natural gas as a fuel is provided with a compression system composed of a multi-stage compressor to compress the evaporated gas discharged from the storage tank to a pressure required by the ME-GI engine, (HICOM); And a vaporization system (HIVAR) for vaporizing the liquefied natural gas inside the storage tank and supplying it to the engine.

According to a ship comprising a conventional compression system and a vaporization system, the compression system controls the pressure inside the storage tank and the vaporization system controls the pressure of the evaporation gas sent from the ME-GI engine to the ME- Respectively.

If the compression system regulates the pressure inside the storage tank and the vaporization system is operated separately to regulate the ME-GI engine shear pressure, the ME-GI engine shear pressure can not be controlled when the vaporization system is stopped, Can not be supplied.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art, in which the compression system can regulate both the pressure inside the storage tank and the pressure at the ME-GI engine, so that when the vaporization system is operated, And the compression system controls the ME-GI engine shear pressure when this stops.

According to an aspect of the present invention, there is provided a compression system for compressing a multi-stage evaporative gas discharged from a storage tank into fuel of an engine. And a vaporization system for vaporizing the liquefied natural gas in the storage tank and supplying the liquefied natural gas to the fuel of the engine, wherein the vaporization system regulates the pressure of the engine front end, The pressure of the storage tank is adjusted, and when the vaporization system is stopped, the pressure of the front end of the engine is adjusted.

The ship may further include a partial re-liquefaction system for re-liquefying the evaporated gas discharged from the storage tank by cooling the evaporated gas discharged from the storage tank with a refrigerant, A heat exchanger for exchanging heat between the evaporated gas discharged from the storage tank and the evaporated gas compressed by the compression system; And a second decompression device for expanding the evaporated gas cooled in the heat exchanger.

The ship may include a plurality of engines, some of which may be ME-GI engines and others may be DF engines, and the vaporization system may control the pressure of the ME- And the compression system can regulate the pressure in the front end of the ME-GI engine when the vaporization system is stopped.

The compression system may include a plurality of compressors and a plurality of coolers alternately connected in series, and the evaporative gas passing through the plurality of compressors may be sent to the ME-GI engine, Evaporative gas may be sent to the DF engine.

The vaporization system comprises: a pump for compressing the liquefied natural gas discharged from the storage tank; A vaporizer for vaporizing the liquefied natural gas compressed by the pump; A first lean pressure device for reducing the vaporized gas vaporized by the vaporizer; And a heater for heating the evaporation gas decompressed by the first decompression device, wherein the evaporation gas passing through the pump and the vaporizer can be partly sent to the ME-GI engine, And may be sent to the DF engine after passing through the first decompressor and the heater.

According to another aspect of the present invention for achieving the above object, there is provided a gas turbine compressor for compressing an evaporative gas discharged from a storage tank by a compression system, a part of evaporated gas compressed by the compression system to an engine, The evaporation gas that has been compressed by the compression system and sent to the heat exchanger is heat-exchanged with the evaporation gas discharged from the storage tank to be cooled, and the evaporation gas cooled by the heat exchanger is expanded and partially or totally re-liquefied Liquid separated liquid is sent to the storage tank, and the gas-liquid separated evaporated gas is merged with the evaporated gas discharged from the storage tank, and the heat exchange < RTI ID = 0.0 > And the evaporation gas discharged from the storage tank is used as the refrigerant of the engine, The liquefied natural gas in the storage tank is compressed and vaporized by the vaporization system and sent to the engine, and when the vaporization system is operated, the vaporization system adjusts the pressure of the front end of the engine, Wherein the compression system adjusts the pressure of the storage tank and the compression system adjusts the pressure of the engine front end when the vaporization system is stopped.

According to another aspect of the present invention, there is provided a system for compressing and vaporizing liquefied natural gas in a storage tank and supplying the compressed natural gas to the engine, A method of supplying fuel to a vessel including a vaporization system, comprising the steps of: 1) determining whether the vaporization system is operating; 2) when the vaporization system is operating, the compression system regulates the pressure of the storage tank; 3) when the vaporization system is operating normally, the vaporization system regulates the pressure in the front end of the engine; And 4) when the vaporization system is stopped, the compression system adjusts the pressure of the front end of the engine.

The step 1) may include determining whether the pressure of the engine front end is equal to or greater than a predetermined value.

According to the present invention, depending on whether or not the vaporization system is operated, the compression system can selectively control the pressure inside the storage tank and the ME-GI engine shear pressure, so that even when the vaporization system is stopped, Can supply.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a fuel supply system of a preferred embodiment applied to a ship of the present invention; Fig.
2 is a schematic view showing a fuel supply method of a preferred embodiment applied to a ship 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 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.

The present invention is applicable to all types of vessels and marine structures equipped with storage tanks capable of storing low temperature liquid cargo or liquefied gas, such as liquefied natural gas carrier, Liquefied Ethane Gas carrier, LNG RV, FPSO, and LNG FSRU. 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.

In this embodiment, the ME-GI engine, which is a typical high-pressure engine, and the DF engine, which is a typical low-pressure engine, are exemplified, but the present invention is not limited thereto. The present invention can be applied to other types of high- Pressure engine.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a fuel supply system of a preferred embodiment applied to a ship of the present invention; Fig.

Referring to FIG. 1, the ship of the present embodiment includes a compression system (HICOM) 300 for compressing the evaporated gas discharged from the storage tank 100 in multiple stages and supplying the compressed fuel to the fuel of the engine; And a vaporization system (HIVAR, 400) for vaporizing the liquefied natural gas in the storage tank 100 and supplying it to the fuel of the engine.

In the compression system 300 of the present embodiment, a plurality of compressors 310 and a plurality of coolers 320 are alternately connected in series, and the evaporation gas discharged from the storage tank 100 is compressed in multiple stages and sent to the engine. The compression system 300 of the present embodiment may be designed to compress the evaporative gas to the pressure required by the ME-GI engine and the evaporative gas that has passed through all the compressors 310 of the compression system 300 is supplied to the ME- The evaporated gas that has been sent to the GI engine and has passed through only a portion of the compressors 310 of the compression system 300 may be partially diverted and sent to the DF engine.

The vaporization system 400 of this embodiment includes a pump 410 for compressing the liquefied natural gas discharged from the storage tank 100; A vaporizer 420 for vaporizing the liquefied natural gas compressed by the pump 410; A first decompression device 430 for decompressing the evaporated gas vaporized by the vaporizer 420 to a pressure required by the DF engine; And a heater 440 for heating the evaporated gas decompressed by the first decompressor 430 to a temperature required by the DF engine. When the evaporation gas in the storage tank 100 is insufficient to satisfy the required amount of the engine, the vaporization system 400 is operated to vaporize the liquefied natural gas in the storage tank 100 and send it to the DF engine and the ME-GI engine . The pump 410 of this embodiment can compress the liquefied natural gas to meet the pressure demanded by the ME-GI engine.

The ship of the present embodiment may further include a partial re-liquefaction system (PRS) 200 for re-liquefying the evaporated gas discharged from the storage tank 100 using the evaporated gas itself as a refrigerant. The partial rem liquefaction system 200 of the present embodiment includes a heat exchanger 210 for exchanging heat between the evaporated gas discharged from the storage tank 100 and the evaporated gas compressed by the compression system 300; A second decompression device 220 which is compressed by the compression system 300 and then is heat-exchanged in the heat exchanger 210 to expand the cooled evaporated gas; And a gas-liquid separator 230 for separating the re-liquefied liquefied natural gas and the gaseous remaining evaporation gas through the compression system 300, the heat exchanger 210, and the second decompression device 220 .

The ship of this embodiment can supply the engine fuel such as MDO, MGO, HFO or the like when the evaporated gas discharged from the storage tank 100 does not satisfy the required amount of the engine.

1, when the vessel of the present embodiment includes the partial liquefaction system 200, the compression system 300, and the vaporization system 400, the evaporation gas inside the storage tank 100 and the liquefied natural gas As fuel of the engine will be described as follows.

The evaporated gas inside the storage tank 100 is sent to the heat exchanger 210 along the L10 line. The evaporated gas sent to the heat exchanger 210 along the L10 line is used as a refrigerant that is compressed by the compression system 300 and then cools the evaporated gas supplied to the heat exchanger 210 along the L20 line.

After being discharged from the storage tank 100, the refrigerant is supplied to the heat exchanger 210 along the L10 line, and the evaporated gas, which is supplied along the L20 line, is heat-exchanged and sent to the compression system 300 to be subjected to a multi- . Some of the evaporative gases which have been only part of the multistage compression process are diverged and sent to the DF engine along the L40 line. One of the evaporation gases branched to the two flows after passing through the compression process in the compression system 300 is sent to the heat exchanger 210 along the L20 line for re-liquefaction, -GI Sent to the engine.

The evaporation gas sent to the heat exchanger 210 along the L20 line after the completion of the compression process in the compression system 300 is heat-exchanged with the evaporation gas discharged along the L10 line from the storage tank 100 in the heat exchanger 210 After being cooled, it is expanded by the second decompression device 220 to partially or totally re-liquefy, and the re-liquefied liquefied natural gas and the gaseous remaining evaporation gas are separated by the gas-liquid separator 230.

The liquefied natural gas separated by the gas-liquid separator 230 is sent to the storage tank 100. The evaporated gas separated by the gas-liquid separator 230 is sent again to the L10 line, and the evaporated gas discharged from the storage tank 100 And is sent to the heat exchanger 210.

The liquefied natural gas inside the storage tank 100 is discharged from the storage tank 100 along the L50 line, then compressed by the pump 410, vaporized by the vaporizer 420, and then branched into two flows. The evaporated gas compressed by the pump 410 and vaporized by the vaporizer 420 may be in a state of satisfying the required pressure of the ME-GI engine. One of the evaporated gases compressed by the pump 410 and vaporized by the vaporizer 420 and then diverted into two flows is depressurized by the first decompressor 430 to a pressure required by the DF engine, 440) to the DF engine and then to the ME-GI engine.

On the other hand, the vaporization system 400 of the present embodiment is provided with an evaporation gas that is compressed by the compression system 300 and then sent to the ME-GI engine at the L30 line in front of the ME-GI engine, The evaporated gas sent to the ME-GI engine in some branch after passing through the evaporator 410 and the vaporizer 420 regulates the pressure of the combined stream.

The compression system 300 of the present embodiment can selectively control the pressure inside the storage tank 100 and the pressure in the L30 line in front of the ME-GI engine. When the vaporization system 400 is operated, the storage tank 100 ) And adjusts the pressure of the L30 line at the front of the ME-GI engine when the vaporization system 400 is stopped.

With the vessel of the present embodiment, the pressure of the L30 line in the front of the ME-GI engine can be continuously adjusted regardless of whether the vaporization system 400 is stopped, so that fuel can be continuously supplied to the engine.

2 is a schematic view showing a fuel supply method of a preferred embodiment applied to a ship of the present invention.

Referring to FIG. 2, the method of supplying fuel to a ship of the present embodiment includes: (S10) determining whether or not a vaporization system is operating; Adjusting the pressure of the storage tank (S21) when the vaporization system is operating; When the vaporization system is operating, the vaporization system regulates the pressure of the L30 line in front of the ME-GI engine (S22); And when the vaporization system is stopped, the compression system adjusts the pressure of the L30 line in front of the ME-GI engine (S30).

Whether or not the gasification system is operating can be determined by determining whether the pressure of the line L30 in the front of the ME-GI engine is equal to or greater than a predetermined value (step S11). For example, if the required pressure of the ME- -If the ME-GI engine is set to stop when the natural gas pressure supplied to the engine is less than 250 bar, it is judged that the vaporization system is stopped when the pressure of the L30 line at the front of the ME-GI engine reaches approximately 270 to 280 bar .

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.

100: Storage tank 200: Partial re-liquefaction system (PRS)
210: heat exchanger 220, 430: decompression device
230: gas-liquid separator 300: compression system (HICOM)
310: compressor 320: cooler
400: vaporization system (HIVAR) 410: pump
420: carburetor 440: heater

Claims (8)

A compression system for compressing and supplying evaporative gas in the storage tank to the engine, and a vaporization system for compressing and vaporizing the liquefied natural gas in the storage tank and supplying the compressed natural gas to the engine,
1) determining whether the vaporization system is operating;
2) when the vaporization system is operating, the compression system regulates the pressure of the storage tank;
3) when the vaporization system is operating normally, the vaporization system regulates the pressure in the front end of the engine; And
4) when the vaporization system is stopped, the compression system regulates the pressure of the engine front end,
And continuously supplies fuel to the engine even when the vaporization system is stopped. The method according to claim 1,
5) The method of claim 1, further comprising the step of heat exchanging the evaporated gas compressed by the compression system with the refrigerant discharged from the storage tank, cooling the evaporated gas, and expanding the evaporated gas. The method according to claim 1 or 2,
The ship includes a plurality of engines,
Some of the plurality of engines are ME-GI engines, others are DF engines,
In step 3), the vaporization system adjusts the pressure of the ME-GI engine,
Wherein the compression system adjusts the pressure in the front end of the ME-GI engine in step 4). The method of claim 3,
The compression system includes a plurality of compressors and a plurality of coolers alternately connected in series,
The evaporated gas that has passed through all of the plurality of compressors is sent to the ME-GI engine,
Wherein evaporative gas passing through only a portion of the plurality of compressors is sent to the DF engine. The method of claim 3,
The vaporization system comprises:
A pump for compressing the liquefied natural gas discharged from the storage tank;
A vaporizer for vaporizing the liquefied natural gas compressed by the pump;
A first decompression device for decompressing the evaporated gas vaporized by the vaporizer; And
And a heater for heating the evaporated gas decompressed by the first decompressor,
The vapor and the vapor passing through the pump and the vaporizer are sent to the ME-GI engine and the other part is sent to the DF engine after passing through the first decompressor and the heater. . delete delete The method according to claim 1,
Wherein the step (1) includes the step of determining whether the pressure of the front end of the engine is equal to or greater than a predetermined value.

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