KR20160014403A - Combined Fuel Gas Supply System And Method For Ship Engine - Google Patents

Abstract

A system and a method for supplying fuel for a ship engine are disclosed. According to the present invention, a system for supplying fuel for a ship engine, in the system to supply gas fuel to a ship engine, comprises: a BOG supply line supplying boil-off gas (BOG) generated in an LNG storage tank to the ship engine; a compressor provided on the BOG supply line to compress the BOG with supply pressure required for the ship engine; an LNG supply line vaporizing LNG stored in the LNG storage tank to be supplied to the ship engine; and a forced vaporizing gas bypass line connected from the LNG supply line to the BOG supply line in upstream of the compressor.

Description

TECHNICAL FIELD [0001] The present invention relates to a fuel supply system for a marine engine,

The present invention relates to a fuel supply system and method for a marine engine, and more particularly, to a BOG supply line for supplying a BOG (Boil-Off Gas) generated in an LNG storage tank to a marine engine, An LNG supply line for supplying LNG stored in the LNG storage tank to the ship engine by vaporizing the LNG stored in the LNG storage tank, and a forced vaporized gas bypass line connecting the LNG supply line to the BOG supply line from the LNG supply line And more particularly, to a fuel supply system and method for a marine engine including a line.

Liquefied natural gas (hereinafter referred to as "LNG") is a colorless transparent liquid obtained by cooling methane-based natural gas to about -162 ° C. and liquefying it. / 600. ≪ / RTI > Therefore, it is very efficient to transport liquefied LNG when transporting natural gas. For example, an LNG carrier that can transport (transport) LNG is used.

Since the liquefaction temperature of natural gas is a cryogenic temperature of -163 ° C at normal pressure, LNG is easily evaporated even if its temperature is slightly higher than the normal pressure of -163 ° C. LNG storage tanks of LNG carriers are heat-treated, but since external heat is continuously transferred to LNG storage tanks, LNG is constantly spontaneously vaporized in LNG storage tanks during LNG transportation by LNG carrier, Boil-off gas (BOG) is generated in the storage tank.

BOG is a kind of LNG loss, which is an important problem in the transport efficiency of LNG. When the evaporation gas accumulates in the LNG storage tank, the pressure in the LNG storage tank is excessively increased, Have been studied.

Recently, for the treatment of BOG, BOG is re-liquefied and returned to the storage tank, and BOG is used as energy source of engine of ship. And, for surplus BOG, the gas combustion unit (GCU) uses a method of burning.

In recent years, the number of vessels using LNG as fuel for ship propulsion and on-ship development has been increasing steadily due to continuous rise in oil prices due to depletion of petroleum resources, price stabilization of natural gas, and strengthening regulations on environmental pollution in each country . In this case, BOG can be used as fuel, and forced vaporized gas in which LNG is vaporized can be used as fuel.

When a dual fuel (DF) engine is applied as the main propulsion unit in the propulsion system of the LNG carrier, the evaporative gas generated in the LNG storage tank can be used as the fuel of the DF engine to treat the evaporative gas . However, in order to supply the evaporation gas as fuel, the compressor having a large power consumption must be operated to compress the gas to the supply pressure of the engine. Especially, in order to secure the redundancy, a large number of compressors must be provided, There is a problem that the cost is high.

On the other hand, if the direct gasification of LNG is supplied as fuel, the power consumption can be lowered but it is difficult to treat the evaporative gas and if the device abnormality occurs at the rear end of the forced vaporized gas, There is a problem.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and it is an object of the present invention to provide an apparatus and a method for supplying LNG and LNG stored in a storage tank, Fuel supply system in which fuel can be supplied to the fuel supply system.

According to an aspect of the present invention, there is provided a system for supplying gaseous fuel to a marine engine,

A BOG supply line for supplying BOG (Boil-Off Gas) generated in the LNG storage tank to the marine engine;

A compressor provided in the BOG supply line for compressing the BOG to a supply pressure required by the marine engine;

An LNG supply line for vaporizing the LNG stored in the LNG storage tank and supplying the LNG to the marine engine; And

And a forced vaporized gas bypass line connected from the LNG supply line to the BOG supply line upstream of the compressor.

Preferably, the LNG supply line is provided with a supply pump provided in the LNG storage tank for pumping LNG, a forced vaporizer for vaporizing the LNG pumped in the supply pump, and a mist vaporizer contained in the forced vaporization gas vaporized in the forced vaporizer a mist gas separator may be provided to separate the mist.

Preferably, the LNG supply line further includes a forced vaporization gas heater which receives the forced vaporized gas from the forced gasified gas separator and heats it to a supply temperature required by the marine engine.

Preferably, the forced vaporized gas bypass line is branched from the LNG supply line upstream of the forced vaporized gas heater, and when the operation abnormality includes an abnormality of the forced vaporized gas heater, the forced vaporized gas is forcedly vaporized Gas supply line to the upstream side of the compressor through the gas bypass line, thereby ensuring redundancy in the operation of supplying the forced vaporized gas.

Preferably, the BOG separator is provided upstream of the compressor in the BOG supply line to remove the mist contained in the BOG, and a BOG separator provided upstream of the forced vaporizer and branched from the LNG supply line and connected upstream of the BOG separator. Line mixer provided at the confluence point of the BOG supply line and the BOG cooling line for supplying the LNG pumped from the supply pump to the BOG through the BOG cooling line to cool the BOG, As shown in FIG.

The controller may further include a temperature controller which is provided downstream of the compressor and adjusts the temperature of the gas compressed by the compressor to a supply temperature required by the marine engine.

Preferably, a gas valve unit (GVU) for regulating the supply of gaseous fuel from the BOG supply line and the LNG supply line may be provided upstream of the marine engine.

Preferably, the marine engine is a DF engine including a DFGE (Dual Fuel Generator).

According to another aspect of the present invention, there is provided a method for supplying gaseous fuel to a marine engine,

BOG (Boil-Off Gas) generated in the LNG storage tank is compressed by a compressor and supplied to the marine engine,

The LNG stored in the LNG storage tank is forcedly vaporized and supplied to the marine engine,

There is provided a line for supplying a gas which is forcedly vaporized to the upstream side of the compressor so that the forced vaporized gas can be selectively compressed by the compressor and supplied to the marine engine.

Preferably, the gas forcibly vaporized by the LNG is supplied to the marine engine by heating with a heater. When the operation abnormality including the abnormality of the heater is supplied, the gas which is forcedly vaporized is supplied to the upstream of the compressor, So that redundancy can be ensured.

In the fuel supply system of a marine engine of the present invention, a BOG supply line for supplying BOG (Boil-Off Gas) to a marine engine and an LNG supply line for supplying LNG stored in the LNG storage tank to the marine engine are provided, It is possible to supply the forced vaporized gas as the fuel, thereby securing the fluidity of the system operation, so that the efficient fuel supply can be achieved.

In particular, a forced vaporized gas bypass line connected from the LNG supply line to the compressor upstream of the BOG supply line is provided so that the operator can supply the forced vaporized gas to the marine engine through the BOG supply line through the compressor, The fluidity can be ensured. It is possible to supply the forced vaporized gas to the marine engine through the BOG supply line even in the case of abnormality in the apparatus downstream of the LNG supply line, so that redundancy can be ensured in the operation of supplying the forced vaporized gas.

1 schematically shows a fuel supply system of a marine engine according to an embodiment 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.

Fig. 1 schematically shows a fuel supply system of a marine engine E1, E2, E3 according to an embodiment of the present invention.

1, the fuel supply system of the present embodiment is a system for supplying gaseous fuel to marine engines E1, E2, and E3. The system includes a boil-off gas (BOG) generated in the LNG storage tank T, BOG supply line BL for supplying the BOG to the marine engines E1, E2 and E3 and a compressor provided in the BOG supply line BL for compressing the BOG to the supply pressures required by the marine engines E1, E2 and E3 And an LNG supply line LL for supplying LNG stored in the LNG storage tank T to the marine engines E1, E2 and E3 by vaporizing the LNG stored in the LNG storage tank T and the compressors 100a and 100b from the LNG supply line LL, 0.0 > (RL) < / RTI > that is connected to the BOG feed line BL upstream from the vapor feed line 100b.

The supply pump 200 for pumping the LNG is connected to the LNG storage tank T for supplying the LNG from the LNG storage tank T to the engines E1, E2 and E3 for forcibly supplying the LNG to the LNG storage tank T A forcing vaporizer 300 provided in the feed pump 200 for vaporizing the LNG pumped in the feed pump 200 and a forcing vaporizer 300 for separating the mist contained in the forced vaporizing gas vaporized in the forced vaporizer 300 A gasified gas separator 400 is provided. The supply pump 200 is provided in a pump type among liquids that can be locked in the LNG inside the LNG storage tank T and the LNG is pumped through the supply pump 200 to be supplied to the forced vaporizer 300 And then vaporized.

LNG is mainly composed of methane (CH ₄ ), but also includes hydrocarbon components such as ethane, propane and butane, and inert gas components such as nitrogen and carbon dioxide. The composition ratio varies depending on the place of production. Because each component has different vaporization points, some components may remain vaporless and remain liquid mist when vaporizing LNG in a forced vaporizer.

Methane number or butane number indicates the composition ratio of the corresponding component in natural gas. If fuel that does not meet the value required by the engine is supplied, knocking phenomenon in the engine, Abnormal combustion phenomena such as explosion and burning may occur before. 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. In the forced gas separator 400, by separating the mist, the forced vaporized gas can be supplied to the marine engines E1, E2 and E3 with the methane or butane number required by the engine.

The LNG supply line LL is additionally provided with a forced vaporizing gas heater 500 that receives the forced vaporized gas from the forced gasified gas separator 400 and heats it to the supply temperature required by the marine engines E1, E2, and E3 do.

The forced vaporized gas bypass line (RL) is branched from the LNG supply line (LL) upstream of the forced vaporized gas heater (500), and when the operation abnormality includes an abnormality of the forced vaporized gas heater (500) Redundancy can be ensured when the forced vaporized gas supply operation is performed by supplying the gas to the upstream of the compressors 100a and 100b of the BOG supply line BL through the forced gas flow bypass line RL.

Redundancy consists of redundant equipment, which is in standby state during operation of the main constituent equipment to perform the required function, and redundant function to take over the function when the main constituent equipment fails to operate due to failure Design. In the present embodiment, when there is an apparatus abnormality such as the forced vaporizing gas heater 500 at the downstream of the LNG supply line LL, the gas is supplied to the marine engines E1, E2, and E3 via the bypass lines via the compressors 100a and 100b It becomes possible to supply the forced vaporized gas, so that it is possible to secure redundancy in the operation of supplying the forced vaporized gas.

A BOG separator 600 for removing the mist included in the BOG is provided in the BOG supply line BL upstream of the compressors 100a and 100b. The BOG separator 600 is provided upstream of the forced vaporizer 300 of the LNG supply line LL, The cooling line CL is branched and connected to the upstream side of the BOG separator 600. An in-line mixer 700 is provided at the confluence point of the BOG supply line BL and the BOG cooling line CL so that the LNG pumped from the supply pump 200 is supplied to the BOG through the BOG cooling line CL, And the BOG to be introduced into the BOG separator 600 is cooled.

The compressors 100a and 100b may be provided with a multi-stage compressor in which compressors are connected in series. The compressors 100a and 100b can be provided in the respective lines branched by the BLA and BLb by branching the BOG supply line BL to a plurality of lines in the compressors 100a and 100b in order to secure redundancy.

A temperature regulator 800 is provided downstream of the compressors 100a and 100b to regulate the temperature of the gas compressed by the compressors 100a and 100b to a supply temperature required by the marine engines E1, E2 and E3. The compressed gas in the compressors 100a and 100b may be a BOG or a forced vaporized gas depending on the system operating conditions. The temperature control unit 800 cools or heats the gas whose temperature has been increased as it is compressed by the compressors 100a and 100b to the supply temperature required by the marine engines E1, E2 and E3.

On the other hand, by providing the LNG supply line LL and the BOG supply line BL, the fuel supply system of the present embodiment has high flexibility, so that the operator can selectively supply the LNG and BOG to the marine engines E1, E2, E3 ). ≪ / RTI >

For example, in the laden condition of the ship in the LNGC, the BOG compressed by the compressors 100a and 100b is compressed through the BOG supply line BL and supplied to the marine engines E1, E2 and E3. In the ballast condition, The liquefied natural gas stored in the storage tank T can be pumped and forcedly vaporized and supplied to the marine engines E1, E2 and E3.

The laden condition of a ship refers to the time when LNG is fully loaded in the LNG storage tank (T). In this case, the amount of BOG generated in the LNG storage tank (T) is large. The ballast condition means that the LNG stored in the LNG storage tank (T) is low due to the unloading of LNG and the amount of BOG generated is small. When the system of the present embodiment is applied, considering the situation of the ship, NBOG, forced vaporized FBOG, NBOG and FBOG are mixed in accordance with laden condition and ballast condition, and mixed BOG is applied to marine engines (E1, E2, E3 To prevent waste of the BOG, and to secure the redundancy of the supply line. When the system is operated so that the FBOG is bypassed to the forced gas flow bypass line (RL) or mixed with the NBOG to compress the mixed BOG and supply it to the engine for the ship, the supply pressure of the feed pump (200) LNG can be pumped down and then forcedly vaporized.

A gas valve unit (GVU, 900) for regulating the supply of gaseous fuel from the BOG supply line (BL) and the LNG supply line (LL) may be provided upstream of the marine engines (E1, E2, E3). The GVU can be installed in the GVU Room (not shown).

The marine engines E1, E2 and E3 in this embodiment may be DF engines such as DFGE (Dual Fuel Diesel Generator) and DFDE (Dual Fuel Diesel Electric Engine). A plurality of marine engines E1, E2, and E3 may be provided.

The DF engine is an engine that burns and burns heavy oil and natural gas. As a result, the amount of sulfur oxides in the exhaust gas is smaller than that of heavy oil alone, It can meet regulatory standards. The DF engine is provided with an oil supply system and a gas supply system for fuel supply, and this embodiment can be applied to the gas supply system.

In the case of DFGE, gaseous fuel can be supplied through the gas supply system at a pressure of 3 to 10 bara and a temperature of -20 to 80 캜, more preferably a pressure of 6.5 bara and a temperature of 0 to 60 캜.

As described above, in the present embodiment, the boil-off gas (BOG) generated in the LNG storage tank T is compressed by the compressors 100a and 100b and supplied to the marine engines E1, E2 and E3, LNG stored in the storage tank T is forcibly vaporized and supplied to the marine engines E1, E2 and E3 so as to provide a bypass line for supplying the forcedly vaporized gas to the upstream of the compressors 100a and 100b, Gas can be selectively compressed by the compressors 100a and 100b and supplied to the marine engines E1, E2 and E3.

The operator can supply the forced vaporized gas to the compressors 100a and 100b through the forced gas flow bypass line RL connected to the BOG supply line BL from the LNG supply line LL upstream of the compressors 100a and 100b, E2, and E3 via the BOG supply line BL through the first and the second BOG supply lines 100b and 100b, thereby securing the fluidity of the system operation and enabling efficient fuel supply.

In addition, when the operation abnormality including an abnormality such as a heater or the like downstream of the LNG supply line is supplied to the upstream side of the compressors 100a and 100b, the forced vaporization gas can be supplied to the upstream of the compressors 100a and 100b to ensure redundancy in the operation of supplying the forced vaporization gas .

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: LNG storage tank
BL: BOG supply line
LL: LNG supply line
RL: forced vaporization bypass line
CL: BOG cooling line
E1, E2, E3: Marine engine
100a, 100b: compressor
200: Feed pump
300: forced vaporizer
400: Forced vaporized gas separator
500: Forced gas heater
600: BOG separator
700: In-line mixer
800: Temperature control unit
900: Gas valve unit

Claims (10)

A system for supplying gaseous fuel to a marine engine,
A BOG supply line for supplying BOG (Boil-Off Gas) generated in the LNG storage tank to the marine engine;
A compressor provided in the BOG supply line for compressing the BOG to a supply pressure required by the marine engine;
An LNG supply line for vaporizing the LNG stored in the LNG storage tank and supplying the LNG to the marine engine; And
And a forced vaporized gas bypass line connected from the LNG feed line to the BOG feed line upstream of the compressor. The LNG supply line according to claim 1, wherein the LNG supply line
A supply pump provided in the LNG storage tank for pumping LNG;
A forced vaporizer for vaporizing the LNG pumped from the feed pump; And
And a forced vaporized gas separator for separating mist contained in the forced vaporizing gas vaporized in the forced vaporizer. 3. The method of claim 2,
Wherein the LNG supply line further comprises a forced vaporizing gas heater for supplying the forced vaporized gas from the forced vaporized gas separator and heating the forced vaporized gas heater to a supply temperature required by the marine engine. The method of claim 3,
The forced vaporized gas bypass line is branched from the LNG supply line upstream of the forced vaporization gas heater,
And supplying the forced vaporizing gas to the compressor upstream of the BOG supply line through the forced vaporizing gas bypass line when operating abnormality including abnormality of the apparatus for the forced vaporizing gas heater, Of the fuel supply system of the marine engine. 3. The method of claim 2,
A BOG separator provided upstream of the compressor in the BOG supply line to remove mist contained in the BOG;
A BOG cooling line branched from the LNG supply line upstream of the forced vaporizer and connected upstream of the BOG separator; And
And an in-line mixer provided at a confluence point of the BOG supply line and the BOG cooling line to supply the LNG pumped from the supply pump to the BOG through the BOG cooling line to cool the BOG The fuel supply system of the marine engine. 6. The method of claim 5,
Further comprising a temperature regulator provided downstream of the compressor for regulating the temperature of the gas compressed by the compressor to a supply temperature required by the marine engine. The method according to claim 1,
And a gas valve unit (GVU) for regulating the supply of gaseous fuel from the BOG supply line and the LNG supply line is provided upstream of the marine engine. The method according to claim 1,
Wherein the marine engine is a DF engine including a DFGE (Dual Fuel Generator). A method for supplying gaseous fuel to a marine engine,
BOG (Boil-Off Gas) generated in the LNG storage tank is compressed by a compressor and supplied to the marine engine,
The LNG stored in the LNG storage tank is forcedly vaporized and supplied to the marine engine,
Wherein a line for supplying a gas which has been forcedly vaporized to an upstream side of the compressor is provided so that the forced vaporized gas can be selectively compressed by the compressor and supplied to the marine engine. 10. The method of claim 9,
The gas in which the LNG is vaporized is heated by a heater and supplied to the marine engine,
Wherein when the operation abnormality including the abnormality of the heater is supplied, the forced vaporized gas is supplied to the upstream of the compressor so that redundancy can be ensured in the operation of supplying the forced vaporized gas.

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