WO2021132955A1 - System and method for supplying liquefied gas to ship, and system for supplying liquefied gas fuel to ship - Google Patents

Abstract

The present invention relates to a system and a method for supplying liquefied gas, which can treat boil-off gas, generated when liquefied gas is supplied to the storage tank of a ship, inside the ship without returning same to the outside. In addition, the present invention relates to a system for supplying liquefied gas fuel to a ship, the system being capable of treating boil-off gas, generated when liquefied gas fuel is supplied to the fuel tank of the ship, inside the ship without returning same to the outside. The system for supplying liquefied gas fuel, of the present invention, which supplies liquefied gas from a liquefied gas supply ship to a ship including a plurality of liquefied gas storage tanks, comprises: a liquefied gas line for supplying the liquefied gas from the liquefied gas supply ship to any one of the plurality of liquefied gas storage tanks; a gas discharge line for discharging the boil-off gas generated by supplying the liquefied gas to the one liquefied gas storage tank; and a gas supply line for supplying the boil-off gas to the one or more other liquefied gas storage tanks.

Description

[Amended by Rule 26 05.01.2021]　Liquefied gas supply system and method for ships and liquefied gas fuel supply system for ships

The present invention relates to a liquefied gas supply system and method capable of processing boil-off gas generated when supplying liquefied gas to a storage tank of a ship in a ship without returning it to the outside.

In addition, the present invention relates to a liquefied gas fuel supply system for a ship that can process boil-off gas generated when liquefied gas fuel is supplied to a fuel tank of a ship without returning it to the outside.

In general, natural gas is produced in a state of liquefied natural gas (LNG) at a production site, and then transported to a gas terminal on land by an LNG carrier.

An empty LNG storage tank provided on a ship is generally filled with an inert gas to prevent gas explosion. That is, a gassing up process of replacing the inert gas filled in the tank with natural gas is performed in the test operation stage before operating the LNG carrier or before storing the LNG in the LNG storage tank of the LNG carrier.

In addition, after the replacement process, a cooling down process of lowering the temperature inside the tank may be performed, and then LNG may be supplied to the tank.

On the other hand, during the cool-down process and supply of LNG, a large amount of boil-off gas (excessive BOG) is generated, and the boil-off gas is generally returned to a gas terminal to maintain the pressure inside the tank.

For example, in the cool-down process step, about 4 to 7 MT/hr of BOG is generated, and in the LNG supply step, about 7 to 9 MT/hr of BOG is generated. At the gas terminal, when supplying LNG, about 4 to 9 MT/hr of BOG is returned from the vessel at each stage as described above, and the BOG is re-liquefied and recovered or processed by burning in a GCU (Gas Combustion Unit). .

On the other hand, as the supply of LNG fueled ships is activated as an alternative measure to solve the environmental pollution problem, the operation of LNG bunkering ships is also increasing. An LNG bunkering vessel is a vessel that directly goes to a ship operating LNG and supplies LNG from an LNG bunkering vessel to an LNG fueled vessel at sea.

Similarly, when supplying LNG from an LNG bunkering vessel to an LNG fuel vessel, a large amount of BOG is generated within the LNG fuel vessel receiving the LNG.

Since the LNG fuel vessel is loaded with cargo, it is not easy to install a pipe to recover BOG, and since BOG is a flammable material, there is a risk of fire or explosion. It is desirable to recover from the vessel and process it in an LNG bunkering vessel.

The LNG fuel tank, which is empty before receiving LNG fuel, is usually filled with an inert gas to prevent gas explosion. That is, a gassing up process of replacing the inert gas in the tank with natural gas is required before storing LNG fuel in an empty LNG fuel tank during the trial operation stage before starting the operation of the LNG fuel vessel or during operation. Do.

In addition, after the replacement process, a cooling down process of lowering the temperature inside the fuel tank may be performed, and then LNG may be supplied to the fuel tank.

On the other hand, during the cool-down process and supply of LNG, a large amount of boil-off gas (excessive BOG) is generated, and the boil-off gas is generally returned to a gas terminal to maintain the pressure inside the tank.

Using such an LNG bunkering vessel, not only refueling LNG fuel from the sea to an LNG fuel vessel, but also various LNG vessels equipped with an LNG storage tank, such as an LNG fuel tank, using an LNG bunkering vessel, for example, LNG for trial operation as an LNG carrier There is an active discussion about the technology to supply.

As described above, in order to supply LNG to an empty LNG storage tank of an LNG carrier subject to trial operation, a replacement process and a cool-down process should be preceded. That is, in order to supply LNG for trial operation to an LNG carrier using an LNG bunkering vessel, the LNG bunkering vessel must be able to directly process the BOG of about 4 to 9 MT/hr recovered from the LNG carrier at each stage.

However, the GCU of the LNG bunkering vessel has limited capacity. In the case of an LNG bunkering vessel that is actually built in Korea with the LNG bunkering function applied, and an LNG bunkering vessel that is actually built by a domestic shipbuilder and is operating in a European port, the GCU capacity is less than 1 ton.

In addition, since the LNG carrier in the trial operation stage is not ready to operate the GCU or reliquefaction device capable of processing BOG, it may be impossible to process BOG in the LNG carrier itself.

As such, in reality, it is impossible to treat all of the BOG generated during cool-down and supply without venting the BOG into the atmosphere.

Accordingly, an object of the present invention is to solve the above problem, and the boil-off gas generated when supplying LNG or LNG for trial operation to an LNG storage tank of an LNG carrier is not recovered to the LNG bunkering ship, but is treated by the LNG carrier itself. An object of the present invention is to provide a system and method for supplying liquefied gas for ships.

Another object of the present invention is to provide a liquefied gas fuel supply system for a ship that can self-treat BOG generated when supplying LNG to an LNG fuel tank of an LNG fuel ship to an LNG bunkering ship, without having to recover the boil-off gas from the LNG fuel ship.

According to one aspect of the present invention for achieving the above object, in the liquefied gas supply system for supplying liquefied gas from a liquefied gas supply vessel to a vessel including a plurality of liquefied gas storage tanks, the liquefied gas supply vessel from the A liquefied gas line for supplying liquefied gas to any one of the plurality of liquefied gas storage tanks; a gas discharge line for discharging boil-off gas generated by supplying liquefied gas to any one of the liquefied gas storage tanks; and a gas supply line for supplying the boil-off gas to one or more other liquefied gas storage tanks.

Preferably, a heater for heating the boil-off gas discharged along the gas discharge line may be further included, and the boil-off gas heated by the heater may be supplied to one or more other liquefied gas storage tanks through the gas supply line.

Preferably, the boil-off gas generated when supplying liquefied gas to one of the liquefied gas storage tanks may be supplied to the other liquefied gas storage tank.

Preferably, the boil-off gas generated when supplying liquefied gas to any one of the liquefied gas storage tanks may be supplied to all other liquefied gas storage tanks.

Preferably, the liquefied gas line connects the liquefied gas supply vessel and the liquefied gas storage tank, and a liquid crossover line through which liquefied gas is transferred from the liquefied gas supply vessel, and the liquid crossover line received It may include a liquid line for supplying branched liquefied gas to each liquefied gas storage tank.

Preferably, the liquid line further includes one or more blocking means for separating the liquid line so that liquefied gas is not supplied to one or more other liquefied gas storage tanks when liquefied gas is supplied through the liquid crossover line. can do.

Preferably, the blocking means may be installed between a point where the liquid crossover line meets the liquid line and a point where the liquid crossover line first meets at that point and branches off to the liquefied gas storage tank.

According to another aspect of the present invention for achieving the above object, in the liquefied gas supply method for supplying liquefied gas from a liquefied gas supply ship to a ship including a plurality of liquefied gas storage tanks, from the liquefied gas supply ship A liquefied gas supply step of supplying the liquefied gas to any one of the plurality of liquefied gas storage tanks; BOG discharging step of discharging BOG generated by supplying liquefied gas to any one of the liquefied gas storage tanks; A liquefied gas supply method is provided, including a gas supply step for substitution of supplying the boil-off gas discharged from the one liquefied gas storage tank to one or more other liquefied gas storage tanks among the plurality of liquefied gas storage tanks.

Preferably, the BOG discharged in the step of discharging BOG may be heated, and the heated BOG may be supplied to one or more other liquefied gas storage tanks.

Preferably, the boil-off gas generated when supplying liquefied gas to one of the liquefied gas storage tanks may be supplied to the other liquefied gas storage tank.

Preferably, the boil-off gas generated when supplying liquefied gas to any one of the liquefied gas storage tanks may be supplied to all other liquefied gas storage tanks.

Preferably, when supplying liquefied gas to any one of the liquefied gas storage tanks of the liquefied gas storage tank, it may be possible to block the supply of liquefied gas to one or more other liquefied gas storage tanks.

According to another aspect of the present invention for achieving the above object, from a liquefied gas supply ship to a liquefied gas carrier including a plurality of liquefied gas storage tanks, a liquefied gas supply method for trial operation for supplying liquefied gas for trial operation In the following, the liquefied gas from the liquefied gas supply vessel, using a stripping line provided to inject the liquefied gas storage tank to the cool-down ready to perform a cool-down process among the plurality of liquefied gas storage tanks Cool-down liquefied gas supply step to supply to the storage tank; Cool-down BOG discharging step of discharging BOG generated in the cool-down storage tank through a gas line provided for discharging gas from the liquefied gas storage tank by supplying liquefied gas to the cool-down storage tank ; and a first replacement gas supply step of supplying the boil-off gas discharged from the cool-down storage tank to a first replacement storage tank ready to perform a replacement process among the plurality of liquefied gas storage tanks; A method of supplying liquefied gas for commissioning of a ship is provided.

Preferably, the first replacement storage tank is filled with an inert gas, the inert gas discharged from the first replacement storage tank by supplying the boil-off gas to the first replacement storage tank, the liquefied gas A first inert gas supplied to the vent mast by using a liquid line provided to store in the liquefied gas storage tank or discharge from the liquefied gas storage tank and a second connect line connecting the liquid line and the vent mast It may further include a discharging step.

Preferably, the first replacement gas supply step includes a BOG treatment step of compressing and heating the BOG discharged from the cool-down storage tank before supplying it to the first replacement storage tank. can do.

Preferably, the amount of BOG discharged from the storage tank for cool-down is equal to or greater than the amount of BOG required for the replacement process of the first replacement storage tank, and when the cool-down of the storage tank for cool-down is completed, The replacement process of the first replacement storage tank may be completed.

Preferably, when the cool-down of the cool-down storage tank is completed, the cool-down storage tank is ready to store the liquefied gas, and the liquefied gas is supplied to the supply storage tank ready to store the liquefied gas. A liquefied gas supply step of supplying the liquefied gas by using a liquid line provided to store or discharge the liquefied gas storage tank from the liquefied gas storage tank; a boil-off gas discharge step of discharging the boil-off gas generated in the supply storage tank through the gas line by supplying the liquefied gas to the supply storage tank; and a second replacement gas supply step of supplying the boil-off gas discharged in the boil-off gas discharge step to a second replacement storage tank ready to perform a replacement process among the plurality of liquefied gas storage tanks. have.

Preferably, the second replacement storage tank is filled with an inert gas, and the inert gas discharged from the second replacement storage tank by supplying the boil-off gas to the second replacement storage tank, the liquid line and The method may further include a step of discharging a second inert gas supplied to the vent mast by using a second connect line connecting the liquid line and the vent mast.

Preferably, the liquid line and the supply storage tank are connected by a first liquid line, and the liquid line and the second replacement storage tank are connected by a third liquid line, and from the liquid line, the second A blocking means may be provided between the branching point of the first liquid line and the branching point of the third liquid line, and the blocking means may be closed in the step of discharging the second inert gas.

Preferably, the second replacement gas supply step includes a second boil-off gas treatment step of compressing and heating the boil-off gas discharged from the supply storage tank before supplying it to the second replacement storage tank. may include

In addition, according to another aspect of the present invention for achieving the above object, from a liquefied gas supply ship, to a liquefied gas carrier including a plurality of liquefied gas storage tanks, liquefied gas for trial operation for supplying liquefied gas for trial operation In the supply system, it is provided to inject the liquefied gas from the liquefied gas supply ship to the liquefied gas storage tank, and among the plurality of liquefied gas storage tanks, a cool-down storage tank ready to perform a cool-down process. Stripping line to which liquefied gas for cool down is transferred; It is provided to store the liquefied gas in the liquefied gas storage tank or to discharge it from the liquefied gas storage tank, and the liquefied gas for trial operation is transferred to a supply storage tank ready to store the liquefied gas after the cool-down is completed. liquid line; and discharging gas from the liquefied gas storage tank, and by supplying the liquefied gas to the cool-down storage tank or the supply storage tank, boil-off gas generated in the cool-down storage tank or the supply storage tank is discharged A storage tank for replacement, including a, wherein the boil-off gas discharged from the storage tank for cool-down and the storage tank for supply through the gas line is ready to perform a replacement process among the plurality of liquefied gas storage tanks A liquefied gas supply system for commissioning of a ship is provided.

Preferably, a second connect line connecting the liquid line and the vent mast; further comprising, the replacement storage tank is filled with an inert gas, and the replacement storage tank by supplying boil-off gas to the replacement storage tank The inert gas discharged from the tank may be transferred to the vent mast through the liquid line and the second connect line.

Preferably, a liquid branch line for supply connecting the liquid line and the storage tank for cool-down or a storage tank for supply; and a liquid branch line for substitution connecting the liquid line and the storage tank for substitution, wherein the liquid branch line for supply is branched from the liquid line and the liquid branch line for substitution is installed between the branching point and the path of the liquid line through which the liquefied gas transferred to the storage tank for cool-down or the storage tank for supply flows by opening/closing control and the path of the liquid line through which the inert gas discharged from the replacement storage tank flows is isolated from each other It may further include a blocking means for doing so.

According to one aspect of the present invention for achieving the above object, in the liquefied gas supply system for supplying liquefied gas from a liquefied gas supply vessel to a vessel including a plurality of liquefied gas storage tanks, the liquefied gas supply vessel from the A liquefied gas line for supplying liquefied gas to any one of the plurality of liquefied gas storage tanks; A liquefied gas storage tank including; a gas supply line for discharging the boil-off gas generated by supplying the liquefied gas to the one of the liquefied gas storage tanks and supplying the boil-off gas to the one or more other liquefied gas storage tanks. The gas discharged from the gas is discharged using the liquefied gas line, and is provided in a liquefied gas line between a liquefied gas storage tank receiving liquefied gas through the liquefied gas line and a liquefied gas storage tank receiving the boil-off gas, , Blocking means for blocking the flow of liquefied gas and boil-off gas flowing along the liquefied gas line so as not to be mixed; further comprising, the liquefied gas supply system is provided.

Preferably, the manifold; and a crossover line connecting the manifold and the liquefied gas line, wherein the blocking means may be a three-way valve provided at a point where the crossover line and the liquefied gas line meet.

Preferably, a heater for heating the boil-off gas discharged along the gas discharge line may be further included, and the boil-off gas heated by the heater may be supplied to one or more other liquefied gas storage tanks through the gas supply line.

Preferably, the gas discharged from the liquefied gas storage tank receiving the boil-off gas is an inert gas, and a connect line connecting the liquefied gas line and the vent mast further comprises, wherein the inert gas is from the liquefied gas storage tank It can be transported to a vent mast.

According to another aspect of the present invention for achieving the above object, in the liquefied gas supply method for supplying liquefied gas from a liquefied gas supply ship to a ship including a plurality of liquefied gas storage tanks, from the liquefied gas supply ship A liquefied gas supply step of supplying the liquefied gas to any one of the plurality of liquefied gas storage tanks; BOG discharging step of discharging BOG generated by supplying liquefied gas to any one of the liquefied gas storage tanks; A replacement gas supply step of supplying the boil-off gas discharged from the one liquefied gas storage tank to one or more other liquefied gas storage tanks among the plurality of liquefied gas storage tanks; and an inert gas discharging step of discharging the inert gas filled in the liquefied gas storage tank supplied with the boil-off gas by receiving the boil-off gas, wherein the inert gas supplies the liquefied gas to the liquefied gas storage tank A method of supplying liquefied gas is provided.

Preferably, in the step of discharging the inert gas, a portion in which liquefied gas flows to the liquefied gas storage tank and a portion in which the inert gas flows are isolated from each other in a line for supplying the liquefied gas to the liquefied gas storage tank. step; may further include.

Preferably, the BOG discharged in the step of discharging BOG may be heated, and the heated BOG may be supplied to one or more other liquefied gas storage tanks.

According to another aspect of the present invention for achieving the above object, from a liquefied gas supply ship to a liquefied gas carrier including a plurality of liquefied gas storage tanks, a liquefied gas supply system for trial operation for supplying liquefied gas for trial operation In each of the plurality of liquefied gas storage tanks, a liquid branch line for transferring liquefied gas; A stripping branch line for liquefied gas injection and a gas branch line for transferring boil-off gas; a gas line provided with, and connecting each gas branch line; and a liquid line connecting each of the liquid branch lines, wherein the plurality of liquefied gas storage tanks are filled with an inert gas, and a replacement storage tank to be subjected to a replacement process; and a storage tank ready to receive liquefied gas by completing the replacement process; from the liquefied gas supply vessel, a liquid branch line or stripping branch line connected to the storage tank ready to receive the liquefied gas supply The boil-off gas discharged from the storage tank ready to receive the liquefied gas supply at the same time as the liquefied gas is supplied using the gas line is transferred to the replacement storage tank through the gas line, and the inert gas filled in the replacement storage tank is There is provided a liquefied gas supply system for test operation of a ship, further comprising a; blocking means for controlling the path to be discharged through the liquid branch line provided in the replacement storage tank.

Preferably, a liquid crossover line connecting the liquid line and the manifold of the liquefied gas carrier is further included, wherein the blocking means is provided at a point where the liquid line and the liquid crossover line are connected. It may be a valve.

Preferably, the blocking means is a point where the liquid branch line of the storage tank ready to receive the liquefied gas is connected to the liquid line and the liquid branch line of the replacement storage tank is connected to the liquid line may be provided in between.

Preferably, the gas line includes a compressor for compressing the boil-off gas; and a heater for heating the boil-off gas compressed by the compressor; may be provided to compress and heat the boil-off gas transferred from the storage tank ready to receive the liquefied gas to the replacement storage tank and supply it.

Preferably, the storage tank ready to receive the liquefied gas comprises: a cool-down storage tank for which the replacement process is completed, a cool-down process target; and a storage tank for supply that is the target of the liquefied gas supply process for trial run on which the cool-down process is completed, wherein the storage tank for cool-down receives liquefied gas through the stripping branch line, and the supply storage tank includes the liquid Liquefied gas can be supplied through the branch line.

Preferably, the replacement storage tank comprises: a first replacement storage tank receiving boil-off gas from the cool-down storage tank; and a second replacement storage tank receiving the boil-off gas from the supply storage tank.

According to one aspect of the present invention for achieving the above object, in a system for supplying liquefied gas fuel from a liquefied gas supply ship to a liquefied gas fuel ship including two or more liquefied gas fuel tanks, storing the liquefied gas fuel a first fuel tank; and a second fuel tank for storing the liquefied gas fuel, and at the same time supplying the liquefied gas fuel from the liquefied gas supply vessel using a liquid branch line or a stripping branch line connected to the first fuel tank, the second A liquefied gas fuel supply system of a ship is provided for supplying the boil-off gas discharged from the first fuel tank as a replacement gas of the second fuel tank through a gas line.

Preferably, the gas line includes a compressor for compressing the boil-off gas; and a heater for heating the boil-off gas compressed by the compressor; may be provided to compress and heat the boil-off gas transferred from the first fuel tank to the second fuel tank and supply it.

Preferably, a liquid line connecting each liquid branch line; and blocking means provided between a point where the liquid branch line of the first fuel tank branches from the liquid line and a point where the liquid branch line of the second fuel tank branches off from the liquid line.

Preferably, when liquefied gas is supplied to the first fuel tank using the liquid branch line, the gas discharged from the second fuel tank is discharged through a liquid branch line connected to the second fuel tank, and the cutoff The means may be closed.

Preferably, a first connect line connecting the liquid branch line of the second fuel tank and the rear end of the blocking means; may further include.

Preferably, when the liquefied gas is supplied to the first fuel tank through the liquid branch line, the gas discharged from the second fuel tank may be discharged to the vent mast through the liquid line and the first connect line. .

The liquefied gas supply system and method for a ship and the liquefied gas fuel supply system for a ship according to the present invention, when supplying LNG to an LNG storage tank such as an LNG carrier or an LNG fuel tank of an LNG fuel ship, evaporation generated in the LNG storage tank The gas can be self-treated onboard the LNG carrier without returning it to the LNG supplier.

In particular, when it is desired to supply LNG during the trial operation stage of an LNG carrier or LNG fuel vessel or when the LNG storage tank is empty, the boil-off gas generated during the LNG cool-down process and the LNG supply process is not recovered to the LNG bunkering vessel. It can be self-disposing on a carrier or LNG fueled vessel.

Therefore, it is possible to supply LNG for trial operation to an LNG carrier or an LNG fueled vessel by using an LNG bunkering vessel at sea.

In addition, it is not necessary to forcibly vaporize the LNG for the replacement process.

In addition, BOG treatment and LNG supply can be performed simultaneously in a vessel supplying LNG.

1 is a conceptual diagram schematically illustrating a liquefied gas supply system according to an embodiment of the present invention.

2 is a view showing the flow state of the fluid during cool-down of the fourth storage tank of the liquefied gas supply system according to an embodiment of the present invention.

3 is a view showing the flow state of the fluid during cool-down of the fourth storage tank of the liquefied gas supply system according to another embodiment of the present invention.

4 is a view showing the flow state of the fluid when supplying LNG to the fourth storage tank of the liquefied gas supply system according to an embodiment of the present invention.

5 is a view showing the flow state of the fluid when supplying LNG to the fourth storage tank of the liquefied gas supply system according to another embodiment of the present invention.

6 is a conceptual diagram schematically illustrating a liquefied gas fuel supply system for a ship according to an embodiment of the present invention.

7 is a view showing the flow state of the fluid during cool-down of the first fuel tank of the liquefied gas fuel supply system of the ship according to an embodiment of the present invention.

8 is a view showing a fluid flow state during cool-down of the first fuel tank of the liquefied gas fuel supply system of a ship according to another embodiment of the present invention.

9 is a view illustrating a flow state of a fluid when LNG is supplied to a first fuel tank of a liquefied gas fuel supply system of a ship according to an embodiment of the present invention.

10 is a view showing the flow state of the fluid when supplying LNG to the first fuel tank of the liquefied gas fuel supply system of the ship according to another embodiment of the present invention.

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

Hereinafter, the configuration and operation of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, in adding reference signs to the elements of each drawing, it should be noted that only the same elements are indicated by the same reference signs as possible even if they are indicated on different drawings. In addition, the following examples may be modified in various other forms, and the scope of the present invention is not limited to the following examples.

In an embodiment of the present invention to be described later, the liquefied gas may be a liquefied gas that can be transported by liquefying the gas at a low temperature, for example, LNG (Liquefied Natural Gas), LEG (Liquefied Ethane Gas), LPG (Liquefied Petroleum) Gas), liquefied ethylene gas (Liquefied Ethylene Gas), may be a liquefied gas such as liquefied propylene gas (Liquefied Propylene Gas). Alternatively, liquid gas such as liquefied carbon dioxide, liquefied hydrogen or liquefied ammonia may be used. However, in the embodiments to be described later, an example in which LNG as a representative liquefied gas is applied will be described.

In addition, in the embodiment to be described later, the ship is described by taking the case of a liquefied natural gas carrier (LNG Carrier) that transports liquefied natural gas as cargo, but the present invention is an LNG FSRU (Floating LNG FSRU) equipped with a storage tank for storing liquefied natural gas. Storage Regasification Unit), LNG FPSO (Floating Production Storage Offloading), LNG RV (Regasification Vessel), etc. Applicable to all offshore structures or ships, including LNG fueled ships equipped with liquefied gas storage tanks or engines supplied with liquefied gas as fuel can do.

In addition, in the embodiment to be described later, the storage tank is a concept including all cargo tanks, fuel tanks, etc., regardless of the name, if it is a tank for storing liquefied gas.

Hereinafter, a liquefied gas supply system and method for a ship and a liquefied gas fuel supply system for a ship according to an embodiment of the present invention will be described with reference to FIGS. 1 to 10 .

A ship according to an embodiment of the present invention performs LNG bunkering in order to supply LNG to a plurality of LNG storage tanks (T1, T2, T3, T4) and a plurality of LNG storage tanks (T1, T2, T3, T4). It includes a manifold connected to a ship or terminal that supplies LNG, such as a ship, and a fluid transfer pipe connecting a plurality of LNG storage tanks (T1, T2, T3, T4) and the manifold.

The fluid transfer pipe includes a liquefied gas line for supplying liquefied gas from an LNG supply vessel to any one of a plurality of LNG storage tanks, and a liquefied gas line for discharging boil-off gas generated by supplying LNG to any one of the LNG storage tanks. It includes a gas discharge line and a gas supply line for supplying boil-off gas to one or more other LNG storage tanks.

In this embodiment to be described later, the liquefied gas line means a liquid line (LL) and a liquid branch line (LL1, LL2, LL3, LL4), a stripping line (SL) and a stripping branch line (SL1, SL2, SL3, SL4) can do.

In addition, the gas discharge line may mean the gas line GL and the gas branch lines GL1, GL2, GL3, GL4, and the first and second connect lines CL1 and CL2, or the liquid line LL and When the gas flows along the liquid branch lines LL1, LL2, LL3, and LL4, it may refer to the liquid line LL and the liquid branch lines LL1, LL2, LL3, and LL4.

In addition, the gas supply line may refer to the gas line GL and the gas branch lines GL1 , GL2 , GL3 , and GL4 .

In this embodiment, the vessel is connected to the LNG bunkering vessel and will be described as an example in which LNG is supplied from the LNG bunkering vessel to the LNG storage tanks T1, T2, T3, and T4 through the manifold.

In addition, in one embodiment of the present invention, the supply of LNG for initial cool-down of the LNG storage tank and LNG for trial operation from an LNG bunkering vessel for the purpose of test operation of the ship will be described as an example. However, the present invention is not limited thereto, and when supplying LNG to an LNG fuel tank of an LNG vessel or supplying LNG to an LNG storage tank, etc., in an LNG vessel equipped with two or more LNG tanks, when receiving LNG from an LNG tank, In any case, it can be applied in various ways.

In addition, although not shown in the drawings, the ship according to this embodiment includes a main engine that generates propulsion energy using LNG stored in LNG storage tanks T1, T2, T3, and T4 as fuel, and an LNG storage tank ( A power generation engine that generates electric energy using LNG stored in T1, T2, T3, and T4) as fuel, and BOG generated by natural vaporization of LNG or LNG stored in LNG storage tanks (T1, T2, T3, T4) A fuel supply unit that supplies fuel to the main engine and power generation engine, a reliquefaction unit that reliquefies BOG and recovers it to LNG storage tanks (T1, T2, T3, T4), and processes BOG or tripped gas from the engine It may include a gas processing unit (100, 200).

In addition, a plurality of LNG storage tanks (T1, T2, T3, T4) may be installed, and in this embodiment, as shown in FIGS. 1 to 5, four LNG storage tanks (T1, T2, T3, T4) It is shown as an example that is provided. As described above, in this embodiment, four LNG storage tanks (T1, T2, T3, T4) are provided as an example, but the present invention is not limited thereto. In addition, in this embodiment, the first storage tank (T1), the second storage tank (T2), the third storage tank (T3) and the fourth sequentially from the LNG storage tank installed in the fore part to the LNG storage tank installed in the stern part It will be referred to as a storage tank (T4).

The manifold is separately provided for a liquid in which a liquid fluid flows and a vapor in which a gaseous fluid flows, but only the liquid manifold (L) necessary for explaining this embodiment is shown in FIGS. 1 to 5 .

The fluid transfer pipe includes a liquid line (LL) and a stripping line (SL) provided to transfer LNG in a liquid state between the manifold (L) and the LNG storage tanks (T1, T2, T3, T4), and a gaseous state and a gas line GL provided to transport natural gas.

The liquid line LL and the stripping line SL are connected through the manifold L and the liquid crossover line LC.

When unloading LNG from the LNG storage tanks (T1, T2, T3, T4) through the manifold (L), and to the LNG storage tanks (T1, T2, T3, T4) through the manifold (L) When supplying (loading) LNG, the LNG may be transferred through the liquid line (LL).

In addition, for the purpose of injecting LNG into the LNG storage tanks (T1, T2, T3, T4) through the manifold (L) and for the purpose of stripping the LNG in the LNG storage tanks (T1, T2, T3, T4), the LNG LNG may flow along the stripping line (SL) when transporting.

The ship of this embodiment further includes a line branching from the liquid line LL toward each of the LNG storage tanks T1, T2, T3, and T4. More specifically, the first liquid line LL1 branching from the liquid line LL to the first storage tank T1, the second liquid line branching from the liquid line LL to the second storage tank T2 ( LL2), the third liquid line LL3 branching from the liquid line LL to the third storage tank T3, and the fourth liquid line LL4 branching from the liquid line LL to the fourth storage tank T4. includes

The first to fourth liquid lines LL1, LL2, LL3, and LL4 extend to the inner bottom surface of the LNG storage tanks T1, T2, T3, and T4, respectively.

In addition, it further includes a line branching from the stripping line (SL) toward each LNG storage tank (T1, T2, T3, T4). More specifically, the first stripping line (SL1) branching from the stripping line (SL) to the first storage tank (T1), the second stripping line branching from the stripping line (SL) to the second storage tank (T2) ( SL2), a third stripping line (SL3) branching from the stripping line (SL) to the third storage tank (T3) and a fourth stripping line (SL4) branching from the stripping line (SL) to the fourth storage tank (T4) includes

The first to fourth stripping lines (SL1, SL2, SL3, SL4) are respectively connected through the liquid dome or gas dome of the LNG storage tanks (T1, T2, T3, T4), and are connected to the injection nozzle installed on the upper part of the tank do. That is, the LNG transferred to the LNG storage tanks T1, T2, T3, and T4 through the first to fourth stripping lines SL1, SL2, SL3, and SL4 is injected and supplied from the top of the tank toward the bottom.

In addition, the length of the first to fourth stripping lines (SL1, SL2, SL3, SL4) may be further extended to the lower part of each of the LNG storage tanks (T1, T2, T3, T4).

The gas line GL of this embodiment connects the boil-off gas processing unit and the LNG storage tanks T1, T2, T3, and T4, and in Figs. 1 to 5, the exhaust gas discharged from the LNG storage tanks T1, T2, T3, and T4 is shown in Figs. Although only the gas line (GL) through which BOG flows is shown, a vapor line provided so that natural gas in gaseous state flows between the LNG storage tanks (T1, T2, T3, T4) and the manifold and the BOG processing unit is further added. may include

The gas line GL includes a branch line connected from the gas dome of each of the LNG storage tanks T1, T2, T3, and T4 to the boil-off gas processing unit. More specifically, the first gas line GL1 branching from the gas line GL to the first storage tank T1, and the second gas line branching from the gas line GL to the second storage tank T2 ( GL2), the third gas line GL3 branching from the gas line GL to the third storage tank T3, and the fourth gas line GL4 branching from the gas line GL to the fourth storage tank T4. includes

In addition, although not shown in the drawing, the BOG processing unit includes a BOG fuel supply unit that compresses BOG generated in the LNG storage tanks (T1, T2, T3, T4) and supplies the BOG as fuel for the engine, and the BOG is recycled. It includes a reliquefaction unit that liquefies and recovers the LNG storage tanks (T1, T2, T3, T4), and a Gas Combustion Unit (GCU) that burns and treats boil-off gas.

In addition, the boil-off gas processing unit, the compressor 100 for pressurizing the boil-off gas generated in the LNG storage tanks (T1, T2, T3, T4); It further includes a heater 200 for heating the boil-off gas compressed by the compressor (100).

Also, although not shown in the drawings, the first to fourth gas lines GL4 may be connected to the vent mast VM for discharging BOG to the atmosphere, respectively. That is, if necessary, the boil-off gas may be vented through the vent mast VM for processing.

In addition, the liquefied gas supply system of the ship according to the present embodiment, the liquid line (LL) and a second connecting line (CL2) for connecting the vent mast (VM); further includes.

The second connecting line CL2 of the present embodiment connects the liquid line LL and the vent mast VM. In addition, the second connecting line CL2 may connect the liquid line LL and the gas dome of the first storage tank T1.

The above-described configurations are generally basic configurations installed in an LNG vessel, and this embodiment utilizes the above-described basic configurations to convert BOG generated when supplying LNG from the LNG bunkering vessel to the vessel of this embodiment into the LNG bunkering vessel. We propose a method that can be disposed of on board the vessel without being returned.

In the embodiment to be described later, the description is based on supplying LNG to the fourth storage tank T4, but is not limited thereto, and even if the description is omitted, other cool-down or LNG supply target LNG storage tanks T1, T2, T3 ), it can be understood that the same applies by changing only the subject when supplying LNG.

According to this embodiment, the cool-down process and the replacement process, and the supply process and the replacement process of the plurality of LNG storage tanks T1, T2, T3, and T4 may be simultaneously performed.

For example, one of the storage tanks after the replacement process is cooled down, and the boil-off gas generated while cooling the storage tank is heated and supplied as a replacement gas of the other storage tank.

In addition, LNG may be supplied to the storage tank after cooling down, and the boil-off gas generated while supplying the LNG may be heated and supplied as a replacement gas of another storage tank.

First, an initial cool-down method of the LNG storage tanks T1, T2, T3, and T4 will be described with reference to FIGS. 2 and 3, and in this embodiment, the fourth storage tank T4 is cooled as a cool-down target storage tank. A method of downloading will be described as a representative example.

The vessel according to the present embodiment is connected to the LNG bunkering vessel through the manifold (L). LNG to cool down the fourth storage tank (T4) from the LNG bunkering vessel is injected and supplied to the fourth storage tank (T4) along the liquid crossover line (LC), the stripping line (SL) and the fourth stripping line (SL4) do.

When the cooling-down LNG is injected and supplied to the fourth storage tank T4 , a large amount of boil-off gas is generated in the fourth storage tank T4 . At this time, the BOG generated in the fourth storage tank (T4) is replaced by the third storage tank (T3), which is the object of the replacement process through the fourth gas line (GL4), the gas line (GL), and the third gas line (GL3). By supplying the solvent gas, it is possible to perform the replacement process of the third storage tank (T3) at the same time as performing the cool-down process of the fourth storage tank (T4).

In addition, the boil-off gas discharged from the fourth storage tank T4 may be compressed by the compressor 100 and heated by the heater 200 , and then supplied as a replacement gas of the third storage tank T3 .

The replacement process takes about 6 hours per storage tank using about 6 to 8 MT/hr of gas, for example, in the case of a ^{173,400M class 3 LNG carrier.} According to this embodiment, the replacement of the storage tank for substitution to be carried out the substitution process by heating the boil-off gas discharged from the cool-down storage tank performing the cool-down process using the heater 200, which is a basic configuration installed in the ship. Supplied as gas.

That is, according to an embodiment of the present invention, a replacement storage tank (T3) adjacent to a storage tank (T4) for cool-down that cool-down and cool-down any one storage tank (T4) for cool-down. A substitution step of can be carried out.

As described above, the empty tank is filled with an inert gas for reasons of drying and safety of the tank. In this way, when the replacement gas is supplied to the third storage tank T3, the third storage tank T3 is filled inside. The existing inert gas is pushed and discharged through the third liquid line LL3.

According to this embodiment, when performing the replacement process of the third storage tank (T3) at the same time as the cool-down process of the fourth storage tank (T4), the inert gas from the third storage tank (T3) to the third liquid line ( LL3).

The inert gas discharged along the third liquid line LL3 is transferred to the vent mast VM along the liquid line LL and the second connecting line CL2 .

That is, while supplying cool-down LNG to the fourth storage tank T4 using the liquid line LL, the inert gas is transferred toward the vent mast VM through the liquid line.

On the other hand, as shown in FIGS. 2 and 3 , by utilizing additional configurations to the above-described basic configurations, BOG generated when supplying LNG from an LNG bunkering vessel to a vessel is not returned to the LNG bunkering vessel. can also be processed.

According to this embodiment, as an additional configuration, the liquid branch lines LL1, LL2, LL3, LL4 that are respectively branched and connected from the liquid line LL to the respective storage tanks T1, T2, T3, T4 are isolated to be described later. a first connecting line (CL1) provided to bypass the valve (IV) to be connected; and an isolation valve (IV) installed on the stern side liquid line (LL) at a point where the first connecting line (CL1) is connected to the liquid line (LL) to block the front and rear flow; may further include.

When the first connecting line CL1 is further included, the inert gas discharged along the third liquid line LL3 may connect the first connecting line CL1, the liquid line LL, and the second connecting line CL2. Accordingly, it may be transferred to a vent mast (VM).

The first connecting line CL1 and the second connecting line CL2 may not be connected from the liquid line LL, but may be directly connected from the third liquid line LL3 to the vent mast VM. In this case, the total length of the connecting lines CL1 and CL2 may be up to 50 m as a pipe of 200A standard based on a 173K class vessel.

For example, the first connecting line CL1 connects the third liquid line LL3 and the rear end of the isolation valve IV provided in the liquid line LL.

The isolation valve IV is installed between the point where the liquid crossover line LC meets the liquid line LL and the point where it branches to the LNG storage tank T4 that first meets at that point.

In addition, the isolation valve IV is installed between a point where the first connecting line CL1 is connected to the liquid line LL and a point where the liquid crossover line LC is connected.

That is, while supplying cool-down LNG to the fourth storage tank T4 using the liquid line LL, the inert gas may be transferred to the vent mast VM through the liquid line LL. At this time, the isolation valve (IV) is in a closed state to block the front and rear flow of the liquid line (LL) with respect to the isolation valve (IV).

On the other hand, the isolation valve IV may be provided at a point where the liquid crossover line LC and the liquid line LL are connected as shown in FIG. 3 , and in this case, the isolation valve IV is a three-way valve. can be provided.

As shown in FIG. 3 , when the isolation valve IV is provided as a three-way valve, as described above, cool-down of the fourth storage tank T4 that is the target of cool-down is performed, and the third storage tank T3 that is the target of replacement. ), the isolation valve (IV) is opened to the side where the third storage tank (T3) and the vent mast (VM) communicate, and the liquid crossover line (LC) communicates with each other. It can be closed to prevent communication.

In this way, when performing the process of replacing the third storage tank (T3) at the same time as performing the cool-down of the fourth storage tank (T4), by controlling the isolation valve (IV), the crossover line (LC) and the stripping line SL communicates with each other, and crossover line LC and liquid line LL do not communicate with each other.

Next, a method of supplying LNG to a ship of this embodiment will be described with reference to FIGS. 4 and 5 , and in this embodiment, a method of supplying LNG to the fourth storage tank T4 will be described as a representative example.

For example, LNG is supplied to one of the supply storage tanks ready to receive LNG by completing the substitution process and the cool-down process, and the boil-off gas generated from the supply storage tank is heated while supplying the LNG to the other one. It can also be supplied as a gas for replacement of the storage tank for replacement of.

The amount of BOG generated while performing the above-described cool-down process of the fourth storage tank T4 is about 120 tons/hr, and this amount is sufficient to complete the replacement process of the third storage tank T3. In addition, after completing the replacement process of the third storage tank (T3), another tank for replacement, for example, a sufficient amount to perform a part of the replacement process of the second storage tank (T2).

Therefore, according to an embodiment of the present invention, which will be described later, when LNG is supplied to the fourth storage tank T4 after completing the cool-down process, the boil-off gas generated in the fourth storage tank T4 is used in the second storage tank T2. ) will be described as an example of performing the substitution step.

That is, substantially as described above, when the cool-down process of the fourth storage tank T4 is performed, the replacement process of the third storage tank T3, which is an adjacent storage tank, is completed. After that, when the LNG is supplied to the fourth storage tank (T4) where the cool-down process is completed, the boil-off gas generated in the fourth storage tank (T4) is the second storage tank (T2) and/or the first storage tank (T1), That is, it can be used to carry out the replacement process of another storage tank.

In the present embodiment, the isolation valve (IV), when supplying LNG to the fourth storage tank (T4) on which the cool-down has been completed, discharges boil-off gas discharged from the fourth storage tank (T4) into the second storage tank (T2) or the second storage tank (T4). 1 In order to supply the gas for replacement of the storage tank (T1), it serves to block the flow direction of the LNG and the flow direction of the replacement gas.

The vessel according to the present embodiment is connected to the LNG bunkering vessel through the manifold (L). The LNG for trial operation to be supplied from the LNG bunkering vessel to the fourth storage tank T4 is supplied to the fourth storage tank T4 along the liquid crossover line LC, the liquid line LL and the fourth liquid line LL4. .

When LNG is supplied to the fourth storage tank T4, a large amount of boil-off gas is generated in the fourth storage tank T4. At this time, the boil-off gas generated in the fourth storage tank T4 is used as a replacement gas in the second storage tank T2 through the fourth gas line GL4, the gas line GL, and the second gas line GL2. By supplying, the process of supplying LNG to the fourth storage tank (T4) can be performed and the replacement process of the second storage tank (T2) can be performed.

In addition, the boil-off gas discharged from the fourth storage tank T4 may be compressed by the compressor 100 and heated by the heater 200 , and then supplied as a replacement gas of the second storage tank T2 .

That is, according to an embodiment of the present invention, at the same time as supplying LNG to any one of the supply storage tanks (T4), the supply storage tank (T4) and the cooling down before the supply process of the supply storage tank (T4) At the same time when performing the process, the substitution process of the storage tank (T2) for another substitution in addition to the storage tank (T3) that has already been completed may be carried out.

As described above, the empty tank is filled with an inert gas for reasons of drying and safety of the tank. In this way, when the replacement gas is supplied to the second storage tank T2, the inert gas filled therein is pushed and the second It is discharged through the liquid line LL2.

According to this embodiment, when supplying LNG to the fourth storage tank (T4) and performing the replacement process of the second storage tank (T2) at the same time, the inert gas is supplied from the second storage tank (T2) to the second liquid line (LL2) is discharged.

The inert gas discharged along the second liquid line LL2 is transferred to the vent mast VM along the liquid line LL and the second connecting line CL2 .

That is, while supplying LNG to the fourth storage tank (T4), which is the stern side storage tank, using the liquid line (LL), the inert gas is vented into the liquid line connected to the bow side based on the isolation valve (IV). It is transferred towards the mast (VM).

At this time, the isolation valve (IV) blocks the flow of the stern side liquid line (LL) and the bow side liquid line (LL) based on the isolation valve (IV) to be in a closed state.

On the other hand, the isolation valve IV may be provided at a point where the liquid crossover line LC and the liquid line LL are connected as shown in FIG. 5 , and in this case, the isolation valve IV is a three-way valve. can be provided.

As shown in FIG. 5, when the isolation valve IV is provided as a three-way valve, LNG is supplied to the fourth storage tank T4, which is a supply storage tank, as described above, and the second storage tank for substitution. When performing the replacement process of the storage tank T2, the isolation valve IV communicates with the liquid crossover line LC and a part of the liquid line LL, and the liquid crossover line LC and the stripping line SL ) is controlled not to communicate.

However, under the control of the isolation valve IV, the liquid crossover line LC and the liquid line LL communicate only with the supply storage tank, that is, the fourth storage tank T4 side, and the replacement storage tank, that is, There is no communication to the second storage tank (T2) side.

In other words, when supplying LNG to the fourth storage tank (T4) and performing the replacement process of the second storage tank (T2) at the same time, supplying LNG to the fourth storage tank (T4) and the second storage tank (T2) Although all of the inert gas discharge from the liquid line LL is made, the isolation valve IV is the basis for the isolation valve IV, in which LNG flows from the manifold (L) to the fourth storage tank (T4). The path and the path through which the inert gas flows from the second storage tank T2 to the vent mast VM are blocked to isolate each other.

Next, a system and method for supplying liquefied gas fuel for a ship according to an embodiment of the present invention will be described with reference to FIGS. 6 to 10 .

A ship according to an embodiment of the present invention connects two or more LNG fuel tanks (T1, T2) and a ship or terminal that supplies LNG, such as an LNG bunkering ship, in order to supply LNG to the LNG fuel tanks (T1, T2). and a manifold (L) to be used, and a fluid transfer pipe connecting the LNG fuel tanks (T1, T2) and the manifold.

The fluid transfer pipe includes a liquefied gas line that supplies LNG from an LNG supply vessel to any one of two or more LNG fuel tanks (T1, T2), and a liquefied gas line that supplies LNG to any one of the LNG fuel tanks. and a gas discharge line for discharging BOG generated by supplying the BOG, and a gas supply line for supplying BOG to one or more other LNG storage tanks.

In this embodiment to be described later, the liquefied gas line may mean the liquid line LL and the liquid branch lines LL1 and LL2, the stripping line SL and the stripping branch lines SL1 and SL2.

In addition, the gas discharge line may refer to the gas line GL and the gas branch lines GL1 and GL2 and the connect line CL, or gas along the liquid line LL and the liquid branch lines LL1 and LL2. When is flowing, it may mean the liquid line LL and the liquid branch lines LL1 and LL2.

In addition, the gas supply line may refer to the gas line GL and the gas branch lines GL1 and GL2 .

The ship of this embodiment may be provided with a plurality of LNG storage tanks, and the plurality of LNG storage tanks may include two or more LNG fuel tanks T1 and T2, and, when the ship is an LNG carrier, one or more LNG storage tanks. It may further include a cargo tank.

In this embodiment, the vessel is connected to the LNG bunkering vessel and receives LNG from the LNG bunkering vessel through the manifold to the LNG fuel tanks T1 and T2, that is, a method of processing boil-off gas during LNG bunkering. do it with

In addition, in one embodiment of the present invention, supplying LNG for initial cool-down of an LNG storage tank or LNG for trial operation from an LNG bunkering vessel for the purpose of bunkering of a vessel, or supplying (recharging) LNG fuel is described as an example do. However, the present invention is not limited thereto, and in the case of supplying LNG to an LNG fuel tank of an LNG fuel vessel or supplying LNG to an LNG fuel tank, in an LNG vessel equipped with two or more LNG tanks, supplying LNG to an LNG tank In any case, it can be applied in various ways.

In addition, although not shown in the drawings, the ship according to the present embodiment includes a main engine that generates propulsion energy using LNG stored in the LNG fuel tanks T1 and T2 as a fuel, and the LNG fuel tanks T1 and T2. A power generation engine that generates electric energy by using LNG stored in a fuel cell, and a fuel that supplies boil-off gas generated by natural vaporization of LNG or LNG stored in LNG fuel tanks (T1, T2) as fuel for the main engine and power generation engine It may include a supply unit, a reliquefaction unit for re-liquefying the boil-off gas and recovering it to the LNG fuel tanks T1 and T2, and gas processing units 100 and 200 for processing the boil-off gas or the tripped gas from the engine.

In addition, two or more LNG fuel tanks T1 and T2 may be provided, and in this embodiment, two LNG fuel tanks T1 and T2 are provided as an example as shown in FIGS. 6 to 10 . did.

As described above, in this embodiment, two LNG fuel tanks T1 and T2 are provided as an example, but the present invention is not limited thereto. In addition, in this embodiment, from the LNG fuel tank installed in the bow part to the LNG fuel tank installed in the stern part will be referred to as a first fuel tank (T1) and a second fuel tank (T2) in turn.

The manifold is separately provided for a liquid in which a liquid fluid flows and a vapor in which a gaseous fluid flows, but only the liquid manifold (L) necessary for explaining this embodiment is shown in FIGS. 6 to 10 .

The fluid transfer pipe is a liquid line (LL) and a stripping line (SL) provided to transfer LNG in a liquid state between the manifold (L) and the LNG fuel tanks (T1, T2), and natural gas in a gaseous state is transferred and a gas line GL provided so as to be possible.

The liquid line LL and the stripping line SL are connected through the manifold L and the liquid crossover line LC.

When unloading LNG from the LNG fuel tanks (T1, T2) through the manifold (L) and when supplying (loading) LNG to the LNG fuel tanks (T1, T2) through the manifold (L) , LNG may be transported through a liquid line (LL).

In addition, when transporting LNG for the purpose of injecting LNG into the LNG fuel tanks (T1, T2) through the manifold (L) and for the purpose of stripping the LNG in the LNG fuel tanks (T1, T2), the stripping line (SL) ) can flow along the LNG.

The ship of this embodiment further includes a liquid branch line branching from the liquid line LL toward each of the LNG fuel tanks T1 and T2. More specifically, the first liquid line LL1 branching from the liquid line LL to the first fuel tank T1 and the second liquid line branching from the liquid line LL to the second fuel tank T2 ( LL2).

The first to second liquid lines LL1 and LL2 may extend to the inner bottom surface of the LNG fuel tanks T1, T2, T3, and T4, respectively.

In addition, it further includes a stripping branch line branching from the stripping line (SL) toward each LNG fuel tank (T1, T2). More specifically, the first stripping line (SL1) branching from the stripping line (SL) to the first fuel tank (T1) and the second stripping line branching from the stripping line (SL) to the second fuel tank (T2) ( SL2).

The first to second stripping lines SL1 and SL2 are respectively connected through the liquid dome or gas dome of the LNG fuel tanks T1 and T2, and are connected to the injection nozzle installed on the upper part of the tank.

That is, the LNG transferred to the LNG fuel tanks T1 and T2 through the first to second stripping lines SL1 and SL2 may be injected and supplied from the upper part of the tank toward the lower part.

In addition, the length of the first to second stripping lines SL1 and SL2 may be further extended to the lower part of the inside of the LNG fuel tanks T1 and T2, respectively.

The gas line GL of the present embodiment connects the boil-off gas processing unit and the LNG fuel tanks T1 and T2, and in FIGS. 6 to 10, the gas line through which the boil-off gas discharged from the LNG fuel tanks T1 and T2 flows ( Although only GL) is shown, a vapor line provided so that natural gas in gaseous state flows between the LNG fuel tanks T1 and T2 and the manifold and the boil-off gas processing unit may be further included.

The gas line GL includes a gas branch line connected from the gas dome of each of the LNG fuel tanks T1 and T2 to the boil-off gas processing unit. More specifically, the first gas line GL1 branching from the gas line GL to the first fuel tank T1 and the second gas line branching from the gas line GL into the second fuel tank T2 ( GL2).

In addition, although not shown in the drawings, the BOG processing unit includes a BOG fuel supply unit that compresses BOG generated in the LNG fuel tanks T1 and T2 and supplies it as fuel for the engine, and re-liquefies BOG for LNG fuel. It may include a reliquefaction unit for recovering to the tanks T1 and T2, and a Gas Combustion Unit (GCU) for burning and processing boil-off gas.

In addition, the boil-off gas processing unit, the compressor 100 for pressurizing the boil-off gas generated in the LNG fuel tanks (T1, T2); A heater 200 for heating the boil-off gas compressed by the compressor 100 may be further included.

Also, although not shown in the drawings, the first to second gas lines GL1 and GL2 may be connected to the vent mast VM for discharging BOG to the atmosphere, respectively. That is, if necessary, the boil-off gas may be vented through the vent mast VM for processing.

In addition, the liquefied gas fuel supply system of the ship according to the present embodiment, the liquid line (LL) and the connecting line (CL) for connecting the vent mast (VM); further includes.

The connecting line CL of this embodiment connects the liquid line LL and the vent mast VM. In addition, the connecting line CL may connect the liquid line LL and the gas dome of the first fuel tank T1.

The above-described configurations are generally basic configurations installed in an LNG vessel, and this embodiment utilizes the above-described basic configurations to convert BOG generated when supplying LNG from the LNG bunkering vessel to the vessel of this embodiment into the LNG bunkering vessel. We propose a method that can be disposed of on board the vessel without being returned.

In the embodiment to be described later, the description is based on supplying LNG to the first fuel tank T1, but the present invention is not limited thereto, and even if the description is omitted, other cool-down or LNG supply target LNG fuel tanks T1 and T2 are used. Even when supplying LNG, it will be understood to be applied in the same way by changing only the target.

According to this embodiment, the cool-down process and the substitution process, and the supply process and the substitution process of two or more LNG fuel tanks T1 and T2 may be simultaneously performed.

For example, one of the fuel tanks T1 after the replacement process is cooled down, and the boil-off gas generated while the fuel tank is cooled down is heated and supplied as a replacement gas of the other fuel tank T2.

In addition, LNG may be supplied to the fuel tank T1 after cooling down, and the boil-off gas generated while supplying the LNG may be heated and supplied as a replacement gas of the other fuel tank T2.

A method of cooling down the LNG fuel tanks T1 and T2 will be described with reference to FIGS. 7 and 8 , and in this embodiment, a method of cooling down the first fuel tank T1 as a fuel tank to be cooled down is taken as a representative example. Explain.

The vessel according to the present embodiment is connected to the LNG bunkering vessel through the manifold (L). LNG to cool down the first fuel tank (T1) from the LNG bunkering vessel is injected and supplied to the first fuel tank (T1) along the liquid crossover line (LC), the stripping line (SL) and the first stripping line (SL1) do.

When the cooling-down LNG is injected and supplied to the first fuel tank T1 , a large amount of boil-off gas is generated in the first fuel tank T1 . At this time, the BOG generated in the first fuel tank T1 is replaced with the second fuel tank T2, which is a replacement process, through the first gas line GL1, the gas line GL, and the second gas line GL2. By supplying the gas with a solvent, the replacement process of the 2nd fuel tank T2 can be implemented simultaneously with implementing the cool-down process of the 1st fuel tank T1.

In addition, the boil-off gas discharged from the first fuel tank T1 may be compressed by the compressor 100 and heated by the heater 200 , and then supplied as a replacement gas of the second fuel tank T2 .

^{In the case of a 173,400M class 3} LNG carrier, the replacement process takes about 6 hours per one fuel tank using about 6 to 8 MT/hr of gas. According to the present embodiment, the second fuel tank to perform the replacement process by heating the boil-off gas discharged from the first fuel tank T1 that performs the cool-down process using the heater 200, which is a basic configuration installed in the ship. It is supplied as a gas for replacement of (T2).

That is, according to an embodiment of the present invention, a replacement fuel tank (T2) adjacent to the cool-down fuel tank (T1) that cools down and cools down any one of the fuel tanks (T1) for cool-down. A substitution step of can be carried out.

As described above, the empty tank is filled with an inert gas for reasons of drying and safety of the tank. In this way, when the replacement gas is supplied to the second fuel tank T2, the second fuel tank T2 is filled inside. The existing inert gas is pushed and discharged through the second liquid line LL2.

According to this embodiment, when performing the replacement process of the second fuel tank T2 simultaneously with the cool-down process of the first fuel tank T1, the inert gas is supplied from the second fuel tank T2 to the second liquid line ( LL2).

The inert gas discharged along the second liquid line LL2 is transferred to the vent mast VM along the liquid line LL and the connecting line CL.

That is, while supplying cool-down LNG to the first fuel tank T1 using the liquid line LL, the inert gas discharged from the second fuel tank T2 is vented using the liquid line LL. It is transferred to the mast (VM).

On the other hand, as shown in FIGS. 7 and 8 , the BOG generated when supplying LNG from an LNG bunkering vessel to a vessel by utilizing additional components to the above-described basic components is returned to the LNG bunkering vessel without returning it to the vessel. can also be processed.

According to this embodiment, as an additional configuration, the isolation valve (IV) installed on the liquid line (LL) to block the front and rear flow; may further include.

The connecting line CL may not be connected from the liquid line LL, but may be directly connected from the liquid branch line to the vent mast VM. In this case, the total length of the connecting line CL may be up to 50m as a pipe of 200A standard based on a 173K class vessel.

The isolation valve IV of this embodiment is a point where the liquid crossover line LC meets the liquid line LL or at the point where any one liquid branch line is branched into any one LNG fuel tank T1, T2. installed between branches.

In the drawing of this embodiment, the isolation valve IV is provided between the point where the liquid crossover line LC meets the liquid line LL and the point where the second liquid line LL2 is branched from the liquid line LL. or provided at a point where the liquid crossover line LC and the liquid line LL meet the liquid line LL is illustrated as an example.

That is, while supplying LNG to the first fuel tank T1 using the liquid line LL or the stripping line SL, the inert gas may be transferred to the vent mast VM through the liquid line LL. have. At this time, the isolation valve (IV) is in a closed state to block the flow of the front and rear ends of the liquid line (LL) based on the isolation valve (IV), so that the inert gas does not flow into the first fuel tank (T1). can do.

On the other hand, when the isolation valve IV is provided at the point where the liquid crossover line LC and the liquid line LL are connected as shown in FIG. 8, the isolation valve IV may be provided as a three-way valve. have.

As shown in FIG. 8 , when the isolation valve IV is provided as a three-way valve, as described above, the cool-down of the first fuel tank T1 is performed, and the replacement target of the second fuel tank T2 is performed. ), the isolation valve (IV) is opened to the side where the second fuel tank (T2) and the vent mast (VM) communicate with each other, and the liquid crossover line (LC) communicates with each other. It can be closed to prevent communication.

In this way, when performing the cooling-down of the first fuel tank T1 and the replacement process of the second fuel tank T2 at the same time, by controlling the isolation valve IV, the crossover line LC and the stripping line SL communicates with each other, and crossover line LC and liquid line LL do not communicate with each other.

Next, a method of supplying LNG to a ship of this embodiment will be described with reference to FIGS. 9 and 10 , and in this embodiment, a method of supplying LNG to the first fuel tank T1 will be described as a representative example.

For example, LNG is supplied to any one fuel tank for supply that is ready to receive LNG by completing the substitution process and the cool-down process, and the boil-off gas generated from the supply fuel tank is heated while supplying the LNG to the other fuel tank. It can also be supplied as a replacement gas for the replacement fuel tank.

The amount of BOG generated while performing the above-described cool-down process of the first fuel tank T1 is about 120 tons/hr, which is sufficient to complete the replacement process of the second fuel tank T2. In addition, after completing the replacement process of the second fuel tank (T2), another replacement target fuel tank or cargo tank replacement process may be performed.

An embodiment of the present invention to be described later exemplifies that when LNG is supplied to the first fuel tank T1, the replacement process of the second fuel tank T2 is performed with the boil-off gas generated in the first fuel tank T1. As described above, although substantially as described above, when the cool-down process of the first fuel tank T1 is performed, the replacement process of the second fuel tank T2, which is an adjacent fuel tank, is completed. After that, when the LNG is supplied to the first fuel tank T1 on which the cool-down process is completed, BOG generated in the first fuel tank T1 is generated in another fuel tank other than the substituted fuel tank during the cool-down of the first fuel tank T1. It can be used to carry out the replacement process of fuel tanks or LNG storage tanks.

In the present embodiment, the isolation valve (IV), when supplying LNG to the first fuel tank (T1), the cool-down is completed, the boil-off gas discharged from the first fuel tank (T1) to the second fuel tank (T2) or or It serves to mutually block the flow direction of the LNG and the flow direction of the replacement gas in order to supply it as a replacement gas for another LNG storage tank.

The vessel according to the present embodiment is connected to the LNG bunkering vessel through the manifold (L). The LNG fuel to be supplied from the LNG bunkering vessel to the first fuel tank T1 is supplied to the fourth fuel tank T1 along the liquid crossover line LC, the liquid line LL, and the first liquid line LL1.

When LNG is supplied to the first fuel tank T1, a large amount of boil-off gas is generated in the first fuel tank T1. At this time, the boil-off gas generated in the first fuel tank T1 is a gas for replacement of the second fuel tank T2 through the first gas line GL1, the gas line GL, and the second gas line GL2. By supplying, while implementing the process of supplying LNG to the 1st fuel tank T1, the replacement process of the 2nd fuel tank T2 can be implemented.

In addition, the boil-off gas discharged from the first fuel tank T1 may be compressed by the compressor 100 and heated by the heater 200 , and then supplied as a replacement gas of the second fuel tank T2 .

That is, according to an embodiment of the present invention, at the same time as supplying LNG to any one of the fuel tanks for supply (T1), the cooling down before the supply process of the supply fuel tank (T1) and the supply fuel tank (T1) At the same time when performing the process, the substitution process of another fuel tank for substitution (T2) in addition to the fuel tank in which the substitution process has already been completed may be performed.

As described above, the empty tank is filled with an inert gas for reasons of drying and safety of the tank. In this way, when the replacement gas is supplied to the second fuel tank T2, the inert gas filled therein is pushed and the second It is discharged through the liquid line LL2.

According to this embodiment, when supplying LNG to the first fuel tank T1 and performing the replacement process of the second fuel tank T2 at the same time, an inert gas is supplied from the second fuel tank T2 to the second liquid line. (LL2) is discharged.

The inert gas discharged along the second liquid line LL2 is transferred to the vent mast VM along the liquid line LL and the connecting line CL.

For example, while supplying LNG to the first fuel tank T4, which is the stern side fuel tank, using the liquid line LL, the liquid line connected to the bow side based on the isolation valve IV is an inert gas It is transported towards the vent mast (VM).

At this time, the isolation valve (IV) blocks the flow of the stern side liquid line (LL) and the bow side liquid line (LL) based on the isolation valve (IV) to be in a closed state.

On the other hand, the isolation valve IV may be provided at a point where the liquid crossover line LC and the liquid line LL are connected as shown in FIG. 10 , and in this case, the isolation valve IV is a three-way valve. can be provided.

As shown in FIG. 10, when the isolation valve IV is provided as a three-way valve, LNG is supplied to the first fuel tank T1, which is a fuel tank for supply, as described above, and a second fuel tank for replacement is supplied. When performing the replacement process of the fuel tank T2, the isolation valve IV communicates with the liquid crossover line LC and the liquid line LL to the side where the first liquid line LL1 is branched, and the second It is controlled so that the liquid line LL2 does not communicate with the liquid line LL on the branched side.

However, under the control of the isolation valve IV, the liquid crossover line LC and the liquid line LL communicate only with the supply fuel tank, that is, the first fuel tank T1 side, and the replacement fuel tank, that is, It does not communicate with the second fuel tank T2 side.

In this way, when supplying LNG to the first fuel tank T1 and performing the replacement process of the second fuel tank T2 at the same time, supplying LNG to the first fuel tank T1 and the second fuel tank T2 All of the inert gas discharge from the liquid line LL is performed, but the isolation valve IV allows LNG to flow from the manifold L to the first fuel tank T1 based on the isolation valve IV. The path and the path through which the inert gas flows from the second fuel tank T2 to the vent mast VM are blocked to isolate each other.

As described above, the embodiments according to the present invention have been reviewed, and the fact that the present invention can be embodied in other specific forms without departing from the spirit or scope of the present invention in addition to the above-described embodiments is recognized by those with ordinary skill in the art. It is self-evident to Therefore, the above-described embodiments are to be regarded as illustrative rather than restrictive, and accordingly, the present invention is not limited to the above description, but may be modified within the scope of the appended claims and their equivalents.

Claims (22)

1. In the liquefied gas supply system for supplying liquefied gas from a liquefied gas supply ship to a ship including a plurality of liquefied gas storage tanks,

   a liquefied gas line for supplying liquefied gas from the liquefied gas supply vessel to any one of the plurality of liquefied gas storage tanks;

   a gas discharge line for discharging boil-off gas generated by supplying liquefied gas to any one of the liquefied gas storage tanks; and

   A liquefied gas supply system comprising a; a gas supply line for supplying the boil-off gas to one or more other liquefied gas storage tanks.
2. The method according to claim 1,

   Further comprising a heater for heating the boil-off gas discharged along the gas discharge line,

   A liquefied gas supply system for supplying the boil-off gas heated by the heater to one or more other liquefied gas storage tanks through the gas supply line.
3. The method according to claim 1,

   A liquefied gas supply system for supplying boil-off gas generated when supplying liquefied gas to the one liquefied gas storage tank to the other liquefied gas storage tank.
4. The method according to claim 1,

   A liquefied gas supply system for supplying boil-off gas generated when supplying liquefied gas to any one of the liquefied gas storage tanks to all other liquefied gas storage tanks.
5. The method according to claim 1,

   The liquefied gas line is

   A liquid crossover line that connects the liquefied gas supply vessel and the liquefied gas storage tank, and the liquefied gas is transferred from the liquefied gas supply vessel, and the liquefied gas supplied through the liquid crossover line is branched into each liquefied gas storage tank A liquefied gas supply system, including a liquid line for supply.
6. 6. The method of claim 5,

   The liquid line is

   The liquefied gas supply system further comprising one or more blocking means for separating the liquid line so that liquefied gas is not supplied to one or more other liquefied gas storage tanks when liquefied gas is supplied through the liquid crossover line.
7. 7. The method of claim 6,

   The blocking means is installed between a point where the liquid crossover line meets the liquid line and a point where the liquid crossover line meets the first meeting point at the point where it branches into the liquefied gas storage tank.
8. The method according to claim 1,

   The gas supply line is used to discharge boil-off gas generated by supplying liquefied gas to the one or more liquefied gas storage tanks and supply it to the one or more other liquefied gas storage tanks,

   The gas discharged from the liquefied gas storage tank receiving the boil-off gas is discharged using the liquefied gas line,

   It is provided in the liquefied gas line between the liquefied gas storage tank receiving the liquefied gas through the liquefied gas line and the liquefied gas storage tank receiving the boil-off gas, and flowing along the liquefied gas line. The liquefied gas supply system further comprising a; blocking means for blocking the flow not to be mixed.
9. 9. The method of claim 8,

   manifold; and

   Further comprising; a crossover line connecting the manifold and the liquefied gas line;

   The blocking means is a three-way valve provided at a point where the crossover line and the liquefied gas line meet.
10. 9. The method of claim 8,

    The gas discharged from the liquefied gas storage tank receiving the boil-off gas is an inert gas,

    It further includes; a connect line connecting the liquefied gas line and the vent mast;

    The inert gas is transferred from the liquefied gas storage tank to the vent mast, liquefied gas supply system.
11. In the liquefied gas supply method for supplying liquefied gas from a liquefied gas supply ship to a ship including a plurality of liquefied gas storage tanks,

    A liquefied gas supply step of supplying liquefied gas from a liquefied gas supply vessel to any one of the plurality of liquefied gas storage tanks;

    BOG discharging step of discharging BOG generated by supplying liquefied gas to any one of the liquefied gas storage tanks; and

    A liquefied gas supply method comprising the step of supplying the boil-off gas discharged from the one liquefied gas storage tank to one or more other liquefied gas storage tanks among the plurality of liquefied gas storage tanks.
12. 12. The method of claim 11,

    A liquefied gas supply method for heating the BOG discharged in the BOG discharge step and supplying the heated BOG to one or more other liquefied gas storage tanks.
13. 12. The method of claim 11,

    A liquefied gas supply method for supplying boil-off gas generated when supplying liquefied gas to one of the liquefied gas storage tanks to the other liquefied gas storage tank.
14. 12. The method of claim 11,

    A liquefied gas supply method for supplying boil-off gas generated when supplying liquefied gas to any one of the liquefied gas storage tanks to all other liquefied gas storage tanks.
15. 12. The method of claim 11,

    When supplying liquefied gas to any one of the liquefied gas storage tanks of the liquefied gas storage tank, blocking the supply of liquefied gas to one or more other liquefied gas storage tanks, liquefied gas supply method.
16. 12. The method of claim 11,

    Further comprising; an inert gas discharging step of discharging the inert gas filled in the liquefied gas storage tank to which the boil-off gas is supplied by receiving the boil-off gas;

    The inert gas is discharged through a line for supplying the liquefied gas to the liquefied gas storage tank, liquefied gas supply method.
17. 17. The method of claim 16,

    The step of discharging the inert gas,

    An isolation step of isolating a portion in which the liquefied gas flows to the liquefied gas storage tank and a portion in which the inert gas flows from among the lines for supplying the liquefied gas to the liquefied gas storage tank; further comprising a liquefied gas supply method .
18. A system for supplying liquefied gas fuel from a liquefied gas supply ship to a liquefied gas fuel ship including two or more liquefied gas fuel tanks,

    A first fuel tank for storing liquefied gas fuel; and

    Includes; a second fuel tank for storing liquefied gas fuel;

    From the liquefied gas supply vessel, liquefied gas fuel is supplied using a liquid branch line or a stripping branch line connected to the first fuel tank, and at the same time, the boil-off gas discharged from the first fuel tank is replaced by the second fuel tank A ship's liquefied gas fuel supply system that supplies gas for use.
19. 19. The method of claim 18,

    Further comprising a gas line through which the boil-off gas is transferred,

    In the gas line,

    a compressor for compressing the boil-off gas; and

    A heater for heating the boil-off gas compressed by the compressor; is provided,

    A liquefied gas fuel supply system for a ship that compresses and heats the boil-off gas transferred from the first fuel tank to the second fuel tank and supplies it.
20. 19. The method of claim 18,

    a liquid line connecting each of the liquid branch lines; and

    A blocking means provided between a point at which the liquid branch line of the first fuel tank branches from the liquid line and a point at which the liquid branch line of the second fuel tank branches from the liquid line; further comprising, liquefaction of the vessel gas fuel supply system.
21. 21. The method of claim 20,

    When liquefied gas is supplied to the first fuel tank using the liquid branch line, the gas discharged from the second fuel tank is discharged through the liquid branch line connected to the second fuel tank, and the blocking means is closed , liquefied gas fuel supply systems for ships.
22. 22. The method of claim 21,

    A connecting line connecting the liquid line and the vent mast; further comprising,

    When the liquefied gas is supplied to the first fuel tank through the liquid branch line, the gas discharged from the second fuel tank is discharged to the vent mast through the liquid line and the connect line, the liquefied gas fuel supply system of the ship .

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