KR20150000161A - LNG Fuel Supply System And Method For Ship - Google Patents

Abstract

Disclosed is a liquefied natural gas (LNG) fuel supply system and method for a ship. The LNG fuel supply system and method for a ship of the present invention comprises: a first vaporizer to vaporize LNG to be supplied to a DF engine of the ship by heat exchange; a heater to additionally heat the LNG vaporized in the first vaporizer; and a second vaporize to vaporize the LNG to be supplied to a main engine of the ship by heat exchange, wherein the first vaporizer, the heater, and the second vaporizer mutually share a thermal medium for heat exchange.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquefied natural gas fuel supply system,

The present invention relates to a system and method for supplying liquefied natural gas fuel to a ship, and more particularly, to a system and method for supplying liquefied natural gas fuel to a ship, comprising a first vaporizer for vaporizing liquefied natural gas supplied to a DF engine of a ship by heat exchange, And a second vaporizer for vaporizing the liquefied natural gas supplied to the main engine of the ship by heat exchange, wherein the first vaporizer, the heater and the second vaporizer are arranged to mutually share a heat medium for heat exchange To a liquefied natural gas fuel supply system of a ship.

In recent years, consumption of liquefied gas such as LNG (Liquefied Natural Gas) and LPG (Liquefied Petroleum Gas) has been rapidly increasing worldwide.

Particularly, Liquefied Natural Gas (hereinafter, referred to as "LNG") is an eco-friendly fuel having a low emission of air pollutants during combustion, and is increasingly used in various fields. Liquefied natural gas is a colorless transparent liquid obtained by cooling methane-based natural gas to about -162 ° C and liquefying it, and has a volume of about 1/600 of that of natural gas. Therefore, it can be transported very efficiently when liquefied by LNG for transporting natural gas.

As international standards for vessels and regulatory standards for each country become increasingly complicated, interest in eco-friendly, high-efficiency fuels is also increasing. One of them is the use of natural gas or vaporized vaporized gas in LNG as fuel for diesel fuel DFDE (Dual Fuel Diesel Engine) which is a heterogeneous fuel engine has been developed and used.

Japanese Patent Application Laid-Open No. 10-2008-0057421 (published on June 25, 2008)

When propulsion or power generation systems use LNG as a fuel, cryogenic LNG must be boosted and vaporized to meet the pressure and temperature requirements of the engine.

A fuel supply system for supplying LNG with vaporized fuel requires a heat source. If a ship is provided with a plurality of fuel supply systems due to a propulsion system and a power generation system, a plurality of heat sources may be supplied depending on the fuel supply system .

The present invention aims at simplifying the structure of the system by providing a DF engine provided on the ship and a fuel supply system capable of mutually sharing heat sources for vaporizing and heating the LNG supplied as fuel to the main engine.

According to an aspect of the present invention, in a liquefied natural gas fuel supply system of a ship,

A first vaporizer for vaporizing the liquefied natural gas supplied to the DF engine of the ship by heat exchange;

A heater for further heating the liquefied natural gas vaporized in the first vaporizer; And

And a second vaporizer for vaporizing the liquefied natural gas supplied to the main engine of the ship by heat exchange,

Wherein the first vaporizer, the heater and the second vaporizer share a heat medium for heat exchange with each other.

Preferably, the apparatus further comprises a first flow path for circulating the heating medium and supplying the heating medium to the first vaporizer, a heating medium heater provided in the first flow path and heated by heat exchange with steam, A second flow path branched from the first flow path to supply the thermal medium to the heater, and a third flow path branched from the first flow path to supply the thermal medium to the second vaporizer.

Preferably, the heat medium tank provided in the first flow path and stored in the heat-exchanged heat medium to be supplied to the heat medium heater, and a heat medium, which supplies the heat medium stored in the heat medium tank to the heat medium heater And may further include a pump.

Preferably, the thermal medium may be GW (glycol water).

Preferably, the DF engine flow path is provided with the first vaporizer and the heater and supplies the liquefied natural gas from the storage tank of the ship to the DF engine, and the second vaporizer is provided, A main engine flow channel supplied to the main engine and a compression pump provided at a front end of the second vaporizer in the main engine flow channel to compress the liquefied natural gas.

Preferably, a fuel pump for pumping the liquefied natural gas stored in the storage tank to supply the liquefied natural gas to at least one of the DF engine flow path and the main engine flow path, and a fuel pump provided in the DF engine flow path, Further comprising a separator for receiving at least one of natural gas and BOG generated from the storage tank to remove HHC, wherein the HHC is removed from the separator, and the liquefied natural gas is supplied to the internal combustion engine It can be controlled by methane number.

According to another aspect of the present invention, there is provided a method of controlling an internal combustion engine, comprising: a forced vaporizer for vaporizing liquefied natural gas supplied to a DF engine of a ship by heat exchange; a heater for additionally heating the vaporized natural gas from the forced vaporizer to supply the DF engine to the DF engine; A fuel supply system comprising a vaporizer for vaporizing the liquefied natural gas supplied to a propulsion main engine by heat exchange,

Wherein the forced vaporizer, the heater and the vaporizer are supplied with the same heat medium heated by steam.

According to another aspect of the present invention, there is provided a method of supplying a liquefied natural gas fuel to a ship,

1) heating the thermal medium with steam;

2) vaporizing the liquefied natural gas to be supplied to the DF engine of the ship by heat exchange with the thermal medium;

3) further heating the vaporized liquefied natural gas with the heating medium;

4) vaporizing the liquefied natural gas supplied to the main engine of the ship with the heating medium,

Wherein the gasification and additional heating of the liquefied natural gas supplied to the DF engine and the thermal medium necessary for gasification of the liquefied natural gas supplied to the main engine are mutually shared, / RTI >

The liquefied natural gas fuel supply system of the present invention comprises a first vaporizer for vaporizing the liquefied natural gas supplied to the DF engine of the ship by heat exchange, a heater for additionally heating the liquefied natural gas vaporized in the first vaporizer, And a second vaporizer for vaporizing the liquefied natural gas supplied to the main engine by heat exchange, wherein the first vaporizer, the heater and the second vaporizer are configured to mutually share the heat medium for heat exchange.

The vaporization and the additional heating of the LNG for fueling the DF engine provided in the ship's power generation system and the vaporization of the LNG for fueling the main engine such as the ME-GI engine provided in the propulsion system of the ship, So that a compact and efficient fuel supply system can be constructed.

1 schematically shows a liquefied natural gas fuel supply system for a ship according to an embodiment of the present invention.
Fig. 2 schematically shows another embodiment of the liquefied natural gas fuel supply system of the present invention.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

1 schematically shows a liquefied natural gas fuel supply system for a ship according to an embodiment of the present invention.

1, a liquefied natural gas fuel supply system for a ship according to an embodiment of the present invention includes a first vaporizer 100 for vaporizing liquefied natural gas supplied to a DF engine DE of a ship by heat exchange, , A heater (200) for further heating the liquefied natural gas vaporized in the first vaporizer (100), and a second vaporizer (300) for vaporizing the liquefied natural gas supplied to the main engine (ME) of the vessel by heat exchange , The first vaporizer (100), the heater (200), and the second vaporizer (300) share a heat medium for heat exchange.

This embodiment includes a DF engine flow path DL for supplying a liquefied natural gas from a storage tank T of a ship to a DF engine DE and a liquefied natural gas The first vaporizer 100 and the heater 200 are provided in the DF engine flow path DL and the second vaporizer 300 and the second vaporizer A compression pump 700 for compressing the liquefied natural gas is provided at a front end of the compressor 300.

The DF engine DE may be a dual fuel diesel engine (DFDE) or a dual fuel diesel generator (DFDE), which constitutes the power generation system of the ship, and the main engine ME may be an ME-GI engine.

Among them, the DF engine (DE) is an engine that burns and burns heavy oil and natural gas. As a result, the sulfur content in the exhaust gas is smaller than that in the case of using only heavy oil as fuel. It is an engine that can meet international emission regulation standards. DFDE and DFDG fueling systems can include two fueling systems: a gas fuel system with natural gas fuel and an oil fuel system with diesel fuel. On the other hand, ME-GI engine is a high-pressure natural gas injection engine of LNG carrier which is developed to reduce nitrogen oxide (NOx) and sulfur oxides (SOx) emissions. The ME-GI engine can be installed on marine structures such as LNG carriers that store LNG (Liquefied Natural Gas) in a cryogenic storage tank (T), and use natural gas and oil as fuel, , The gas supply pressure of about 150-400 bara (absolute pressure) is required. The emission amount of the pollutants is reduced by 23%, nitrogen compound 80%, and sulfur compound 95% or more, It is becoming popular as a next-generation eco-friendly engine. When the LNG is supplied to the ME-GI engine, the fuel supply system is configured to supply the BOG generated in the storage tank T, or to compress the LNG to a high pressure and supply it to the evaporator.

In this embodiment, the heat source necessary for the gas fuel system part of the fuel supply system of the DF engine DE and the heat source necessary for the LNG vaporization of the fuel supply system of the ME-GI engine can be mutually shared Fuel supply system.

The present embodiment includes a first flow path L1 in which a heating medium circulates and supplies a heating medium to the first vaporizer 100, and a first flow path L1 is provided with a heating medium A heater 400 is provided. A second flow path L2 for supplying the heating medium to the heater 200 and a third flow path L3 for supplying the heating medium to the second vaporizer 300 are branched from the first flow path L1.

The heat medium that has undergone the heat exchange in the first vaporizer 100, the heater 200 and the second vaporizer 300 via the first flow path L1, the second flow path L2 and the third flow path L3, Is stored in the tank 500 and is supplied to the heat medium heater 400 through the heat medium pump 600 and heated again through heat exchange with the steam to be supplied to the heat source and circulated.

On the other hand, the present embodiment heats the LNG by heating the heating medium with steam without heat exchanging the LNG directly with the steam in the fuel supply system, and then heat-exchanges with the heated heat medium again. In the case of heating LNG by direct heat exchange with steam, especially in the case of DFDG, since the amount of liquefied natural gas supplied as fuel is small, excessive heat energy is supplied more than necessary, and control of the process after heating may become difficult. This embodiment differs from the DF engine (DE) in that the heat medium is heated by the steam in the heat medium heater (400) without indirect heat exchange with the liquefied natural gas, and then the liquefied natural gas is indirectly heated through the heated heat medium. And the main engine (ME), smooth control of the process and stable operation can be achieved.

In this embodiment, the circulating heat medium may be GW (glycol water).

The storage tank T is provided with a fuel pump 800 for pumping the stored liquefied natural gas to supply it to at least one of the DF engine flow path DL and the main engine flow path ML.

A separator 900 for receiving at least one of liquefied natural gas passing through the first vaporizer 100 and BOG generated in the storage tank T and removing HHC (heavy hydrocarbons) is provided in the DF engine flow path DL By removing the HHC from the separator 900, the methane value of the liquefied natural gas can be controlled by the methane number required by the internal combustion engine.

In addition to methane, natural gas includes hydrocarbons having a plurality of hydrocarbons such as ethane, propane, butane, and pentane, and inert gas components such as nitrogen and carbon dioxide. The composition ratio varies depending on the place of production. Methane number indicates the composition ratio of methane in natural gas. If fuel that does not meet the methane required by the engine is supplied, knocking phenomenon in the engine or explosion or combustion of the piston before top dead center An abnormal combustion phenomenon may occur. Such an abnormal combustion phenomenon may cause wear of the engine piston, and may cause problems such as deterioration of engine efficiency and device failure. The present embodiment can increase the methane price of the fuel to be supplied to the DF engine DE to such an extent that the engine needs to prevent the abnormal combustion phenomenon. When adopting the ME-GI engine as the main engine (ME), the ME-GI engine does not require the adjustment of methane, whereas the DF engine (DE) generally requires more than 80 methane. However, liquefied natural gas (LNG) supplied to the DF engine (DE) needs methane control because the methane level of the liquefied natural gas may range from about 70 to about 70 depending on the place of production.

Ethane, propane, butane, etc. contained in forced vaporized liquefied natural gas have higher liquefaction point than methane. Therefore, in the separator 900, the methane gas of the liquefied natural gas is removed to a level required by the engine by removing the liquefied heavy hydrocarbons at a temperature at which the heavy hydrocarbons (HHC) such as propane and butane can be liquefied while maintaining the gas state .

Particularly, since the various hydrocarbons contained in the liquefied natural gas have different liquefaction points, the heating temperature of the liquefied natural gas in the first vaporizer 100 is controlled in consideration of the composition of the liquefied natural gas and the methane required by the engine The amount of heavy hydrocarbons removed in the separator 900 can be controlled. The vaporization temperature of the liquefied natural gas heated in the first vaporizer 100 is in the range of -80 to -120 ° C. and the vaporization temperature can be controlled within the above range in consideration of different compositions depending on the place where the liquefied natural gas is produced.

The separator 900 separates and removes heavy hydrocarbon components contained in vaporized liquefied natural gas from a packing portion (not shown) on the upper part of the separator 900 and separates the separated heavy hydrocarbon liquid And can be returned to the storage tank (T).

The vaporized liquefied natural gas can be adjusted to have a methane value of 80 or more, preferably 90 or more, and more preferably 95 or more, while passing through the separator 900 at 70 or more methane gas. As the methane gas is regulated, the lower heating value (LHV) of the separator 900 is higher than that before the separator 900 is fed to the DF engine DE. Since the BOG generated in the storage tank T is mostly composed of methane, it may not be necessary to adjust the methane amount of the BOG. Therefore, The system may be configured to be introduced into the system 200.

For example, in the case of General LNG (C1: 89.6%, N2: 0.6%), the methane level before separation is 71.3 and the lower heating value at that time is 48,872.8 kJ / kg (1 atm, saturated vapor basis) 7 bara, the mixture is heated to -120.degree. C. By vaporizing and separating the liquid through the separator 900, the methane gas is changed to 95.5 and the LHV is changed to 49,265.6 kJ / kg.

The vaporized liquefied natural gas is further heated through the heat medium in the heater 200 after passing through the separator 900 and supplied to the DF engine DE at a temperature of -30 to 80 캜, preferably 0 to 60 캜 .

According to another aspect of the present invention, there is provided a propulsion system for a ship, comprising: a forced vaporizer for vaporizing liquefied natural gas supplied to a DF engine of a ship by heat exchange; a heater for additionally heating the vaporized natural gas from the forced vaporizer to supply it to the DF engine; 1. A fuel supply system comprising a vaporizer for vaporizing liquefied natural gas supplied to a main engine by heat exchange,

A forced vaporizer, a heater and a vaporizer are supplied with the same heat medium heated by steam, and a liquefied natural gas fuel supply system of the ship is provided.

According to another aspect of the present invention, there is provided a method of supplying liquefied natural gas fuel to a ship,

1) heating the thermal medium with steam;

2) vaporizing the liquefied natural gas to be supplied to the DF engine (DE) of the ship by heat exchange with a thermal medium;

3) further heating the vaporized liquefied natural gas as a heating medium;

4) vaporizing the liquefied natural gas supplied to the main engine (ME) of the ship as a thermal medium,

Characterized in that the gasification and further heating of the liquefied natural gas supplied to the DF engine (DE) and the thermal medium necessary for vaporization of the liquefied natural gas supplied to the main engine (ME) are mutually shared. Method is provided.

As described above, the liquefied natural gas fuel supply system of the ship includes a first vaporizer 100 for vaporizing the liquefied natural gas supplied to the DF engine DE of the ship by heat exchange, a second vaporizer 100 for vaporizing A heater (200) for further heating the liquefied natural gas; and a second vaporizer (300) for vaporizing the liquefied natural gas supplied to the main engine (ME) of the ship by heat exchange, wherein the first vaporizer (100), the heater 200 and the second vaporizer 300 are configured to mutually share the heat medium for heat exchange.

The gasification and further heating of the LNG for supplying the fuel of the DF engine DE provided in the power generation system of the ship and the LNG for the fuel supply of the main engine ME such as the ME- By providing vaporization with a single thermal medium, it is possible to construct a compact, efficient and integrated LNG fuel supply system of the propulsion system and power generation system.

In addition, by indirect heat exchange instead of direct heating, LNG can be operated stably without any effect of sudden phase change of fuel.

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 or scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

T: Storage tank
L1: first flow path L2: second flow path
L3: Third Euro
DL: DF engine flow ML: Main engine flow
DE: DF engine ME: main engine
100: First vaporizer 200: Heater
300: Second vaporizer
400: thermal medium heater 500: thermal medium tank
600: Thermal medium pump
700: Compressor pump
800: Fuel pump
900: Separator

Claims (8)

A liquefied natural gas fuel supply system for a ship,
A first vaporizer for vaporizing the liquefied natural gas supplied to the DF engine of the ship by heat exchange;
A heater for further heating the liquefied natural gas vaporized in the first vaporizer; And
And a second vaporizer for vaporizing the liquefied natural gas supplied to the main engine of the ship by heat exchange,
Wherein the first vaporizer, the heater and the second vaporizer share a heat medium for heat exchange with each other. The method according to claim 1,
A first flow path for circulating the heat medium and supplying the heat medium to the first vaporizer;
A heating medium heater provided in the first flow path and heating the heating medium by heat exchange with steam;
A second flow path branched from the first flow path and supplying the heat medium to the heater; And
And a third flow path branched from the first flow path and supplying the thermal medium to the second vaporizer. 3. The method of claim 2,
A heat medium tank provided in the first flow path and storing the heat-exchanged heat medium and supplied to the heat medium heater; And
And a thermal medium pump for supplying the thermal medium stored in the thermal medium tank to the thermal medium heater. 3. The method of claim 2,
Wherein the thermal medium is GW (Glycol water). The method according to claim 1,
A DF engine flow path provided with the first vaporizer and the heater and supplying liquefied natural gas from the storage tank of the ship to the DF engine;
A main engine flow passage provided with the second vaporizer and supplying liquefied natural gas from the storage tank to the main engine; And
Further comprising a compression pump provided at a front end of the second vaporizer in the main engine flow passage for compressing the liquefied natural gas. 6. The method of claim 5,
A fuel pump for pumping the liquefied natural gas stored in the storage tank and supplying the liquefied natural gas to at least one of the DF engine flow path and the main engine flow path; And
Further comprising a separator provided in the DF engine flow passage for receiving at least one of the liquefied natural gas passed through the first vaporizer and the BOG generated in the storage tank to remove heavy hydrocarbons,
And removing the HHC from the separator to adjust the liquefied natural gas to a methane number required by the internal combustion engine. A forced vaporizer for vaporizing the liquefied natural gas supplied to the DF engine of the ship by heat exchange; a heater for further heating the natural gas vaporized in the forced vaporizer to supply the natural gas to the DF engine; A fuel supply system comprising a vaporizer for vaporizing liquefied natural gas by heat exchange,
Wherein the forced vaporizer, the heater and the vaporizer are fed with the same heat medium heated by steam. A method for supplying liquefied natural gas fuel to a ship,
1) heating the thermal medium with steam;
2) vaporizing the liquefied natural gas to be supplied to the DF engine of the ship by heat exchange with the thermal medium;
3) further heating the vaporized liquefied natural gas with the heating medium; And
4) vaporizing the liquefied natural gas supplied to the main engine of the ship with the heating medium,
Wherein the gasification and additional heating of the liquefied natural gas supplied to the DF engine and the thermal medium necessary for vaporization of the liquefied natural gas supplied to the main engine are mutually shared.

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