KR102374661B1 - Bunkering Vessel - Google Patents

Abstract

A bunkering vessel according to the present invention is for loading and unloading liquefied gas into a liquefied gas storage tank of a target, and includes: a bunkering tank for storing liquefied gas; a manifold provided at the bunkering station of the bunkering vessel to flow in and out of the liquefied gas from the bunkering vessel; a liquefied gas transfer line connecting the bunkering tank and the manifold to flow the liquefied gas; and a liquefied gas supply line branching from the liquefied gas transfer line and supplying liquefied gas from the bunkering tank to the gas combustion unit, wherein the gas combustion unit burns and processes boil-off gas generated in the bunkering tank. characterized.

Description

Bunkering Vessel

The present invention relates to a bunkering vessel.

Recently, as environmental regulations are strengthened, the use of liquefied natural gas, which is close to an eco-friendly fuel, among various fuels is increasing. Liquefied natural gas is generally transported through LNG carriers, and at this time, the liquefied natural gas can be stored in the tank of the LNG carrier in a liquid state by lowering the temperature to -162°C or less under 1 atm. When liquefied natural gas becomes liquid, its volume is reduced to 1/600 compared to the gaseous state, so transport efficiency can be increased.

Unlike diesel, in the case of loading or unloading liquefied natural gas into a vessel that transports or uses such liquefied natural gas as fuel, it must be maintained at a cryogenic temperature. In addition, it is necessary to control the temperature and pressure of the storage tank in which the liquefied natural gas is stored for stable storage of the liquefied natural gas while performing loading and unloading. Therefore, in recent years, continuous research and development has been made on a bunkering technology for maintaining liquefied natural gas in a liquid state and supplying it to a liquefied natural gas carrier or a propulsion ship and a ship using the same.

Unexamined Patent Publication No. 10-2019-0114456 (2019. 10. 10., published)
Laid-open Patent Publication No. 10-2016-0144886 (2016. 12. 19., published)
Laid-Open Patent Publication No. 10-2016-0120182 (2016. 10. 17., published)
Unexamined Patent Publication No. 10-2016-0120213 (2016. 10. 17., published)

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is to provide a bunkering vessel capable of loading and unloading liquefied gas into a target liquefied gas storage tank.

In addition, an object of the present invention is to provide a vessel capable of controlling the temperature and pressure conditions inside the liquefied gas storage tank of the target to satisfy the conditions required in the individual process for loading and unloading liquefied gas in the bunkering vessel. it is to do

A bunkering vessel according to an aspect of the present invention is for loading and unloading liquefied gas into a liquefied gas storage tank of a target, a bunkering tank for storing liquefied gas, a bunkering station of the bunkering vessel and liquefied from the bunkering vessel A manifold for flowing in and out of gas, a liquefied gas transfer line connecting the bunkering tank and the manifold to flow liquefied gas, and a liquefied gas branching from the liquefied gas transfer line and supplying liquefied gas from the bunkering tank to the gas combustion unit and a supply line, wherein the gas combustion unit burns and processes the boil-off gas generated in the bunkering tank.

Specifically, the liquefied gas transfer line may include a liquid transfer line for transferring the liquefied gas in the liquid phase, and a gaseous transfer line for transferring the liquefied gas in the gas phase.

Specifically, the gas phase transfer line may be supplied with boil-off gas generated in the liquefied gas storage tank.

Specifically, the gas phase transfer line may transfer at least a portion of the supplied boil-off gas to the liquefied gas supply line.

Specifically, the liquefied gas supply line may include a gas-liquid separator that separates the liquefied gas into a gaseous phase and a liquid phase and returns the liquefied gas in the liquid phase to the bunkering tank.

Specifically, the bunkering vessel may further include a buffer tank for storing at least a portion of the pressurized liquefied gas.

Specifically, the bunkering station may be provided on the upper deck of the bunkering vessel, and the manifold may be disposed on at least one of a side chord and a stern of the bunkering vessel.

Specifically, the target may be a liquefied gas propulsion ship propelling liquefied gas as fuel.

The bunkering vessel according to the present invention can load and unload cryogenic liquefied gas to a target liquefied gas storage tank, and load and unload conditions such as temperature and pressure inside the liquefied gas storage tank. Individual process for loading and unloading It can be controlled according to the conditions required by

In addition, the bunkering vessel according to the present invention can minimize unwanted vaporization of the liquefied gas during the loading and unloading process of the liquefied gas.

In addition, the bunkering vessel according to the present invention can process the exhaust gas generated during the loading and unloading process of the target liquefied gas storage tank.

In addition, the bunkering vessel according to the present invention can process boil-off gas generated inside the bunkering tank by itself.

1 is a conceptual diagram of a bunkering system of a bunkering vessel according to an embodiment of the present invention.
2 is a conceptual diagram illustrating a gas treatment process before bunkering in a bunkering vessel according to an embodiment of the present invention.
3 is a conceptual diagram illustrating a process of processing BOG generated in a target liquefied gas storage tank before bunkering in a bunkering vessel according to an embodiment of the present invention.
4 is a conceptual diagram illustrating a drying process for supplying a drying gas or an inert gas supplying a drying gas in a bunkering vessel according to an embodiment of the present invention.
5 is a conceptual diagram illustrating a drying process for supplying a drying gas or an inert gas for supplying a drying gas in a bunkering vessel according to an embodiment of the present invention.
6 is a conceptual diagram illustrating a first gassing-up process of supplying liquefied gas to a liquefied gas carrier in a bunkering vessel according to an embodiment of the present invention.
7 is a conceptual diagram illustrating a secondary gassing-up process for supplying liquefied gas to a liquefied gas carrier in a bunkering vessel according to an embodiment of the present invention.
8 is a conceptual diagram illustrating a first gassing-up process for supplying liquefied gas to a liquefied gas propulsion ship in a bunkering vessel according to an embodiment of the present invention.
9 is a conceptual diagram illustrating a secondary gassing-up process for supplying liquefied gas to a liquefied gas propulsion ship in a bunkering vessel according to an embodiment of the present invention.
10 is a conceptual diagram illustrating a cool-down process of supplying liquefied gas in a bunkering vessel according to an embodiment of the present invention.
11 is a conceptual diagram illustrating a process of loading liquefied gas into a target liquefied gas storage tank in a bunkering vessel according to an embodiment of the present invention.
12 is a conceptual diagram illustrating a gas processing process after bunkering in a bunkering vessel according to an embodiment of the present invention.
13 is a conceptual diagram illustrating a first warm-up process of supplying high-temperature liquefied gas to a target liquefied gas storage tank in a bunkering vessel according to an embodiment of the present invention.
14 is a conceptual diagram illustrating a secondary warming-up process of supplying high-temperature liquefied gas to a target liquefied gas storage tank in a bunkering vessel according to an embodiment of the present invention.
15 is a conceptual diagram illustrating a gas freeing process for treating exhaust gas supplied from a target liquefied gas storage tank in a bunkering vessel according to an embodiment of the present invention.
16 is a conceptual diagram illustrating an aeration process for supplying dry gas in a bunkering vessel according to an embodiment of the present invention.
17 is a conceptual diagram illustrating an aeration process for supplying dry gas in a bunkering vessel according to an embodiment of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In the present specification, in adding reference numbers to the components of each drawing, it should be noted that only the same components are given the same number as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, it should be noted that high pressure (HP), low pressure (LP: low pressure), high temperature and low temperature are relative, do not represent absolute values, and may be relatively used according to each embodiment of the present invention.

Hereinafter, the bunkering vessel means a vessel capable of loading and unloading liquefied gas into a target liquefied gas storage tank, and using the stored liquefied gas as fuel.

Hereinafter, it should be noted that the target is used in the meaning of encompassing all marine plants such as FSRUs and FPSOs in addition to liquefied gas carriers that transport liquefied gas as cargo and liquefied gas propulsion ships that can use liquefied gas as fuel. In addition, the target may include other bunkering ships and liquefied gas transport vehicles having liquefied gas storage tanks. However, in a specific embodiment of the present invention, the subject may be limited to any one or more of the above.

Hereinafter, when the target is a liquefied gas carrier, the bunkering vessel according to the present invention may be provided to perform the following process for the test operation of the liquefied gas carrier.

Hereinafter, liquefied gas may be used to encompass all gas fuels generally stored in a low-temperature liquid state, such as LNG, LPG, ethylene, ammonia, and the like. However, in the following embodiments and drawings, the liquefied gas will be described as an example of liquefied natural gas.

Hereinafter, boil-off gas (BOG, Boil Off Gas) may refer to a liquefied gas that is naturally vaporized or forcedly vaporized. However, the boil-off gas may be used to include not only gaseous boil-off gas but also liquefied boil-off gas. In addition, it should be noted that liquefied gas may be used as a term encompassing both a liquid state, a natural vaporized gas state, or a forced vaporized gas state hereinafter.

Hereinafter, bunkering refers to a loading (loading) of supplying liquefied gas to a target from a bunkering vessel and unloading that a bunkering vessel is supplied with by withdrawing liquefied gas from the target.

Hereinafter, that the bunkering vessel is connected to the target means a state in which the manifold and the pipe are connected so that liquefied gas, boil-off gas, or other gas can communicate between the bunkering vessel and the target.

Hereinafter, expressions such as first, second, etc. are intended to indicate that a plurality of specific components are provided in the present invention, and each expression may refer to any one of a plurality of components.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram illustrating a bunkering system as an internal system of a bunkering vessel according to an embodiment of the present invention.

Referring to FIG. 1 , the bunkering vessel includes a bunkering tank 10 , a manifold 20 , a liquefied gas transfer line, a gas supply unit 30 , a buffer tank 40 , and the like. Hereinafter, although not shown, each line may include a valve for controlling the flow rate of the fluid flowing through the corresponding line.

The bunkering tank 10 may be a storage tank that is mounted on the inside of a bunkering vessel to store liquefied gas for loading and unloading into a target liquefied gas storage tank. The bunkering tank 10 may be a membrane tank having a membrane type insulation structure suitable for storing cryogenic liquefied gas. A plurality of bunkering tanks 10 may be provided inside the bunkering vessel. For example, the bunkering tank 10 may be provided in parallel along the stern from the bow of the ship, or may be provided in parallel to the port and starboard of the ship, respectively.

The bunkering tank 10 may be connected to a manifold 20 to be described later and supply liquefied gas stored therein to the target through the manifold 20 or may receive liquefied gas from the target. Specifically, a liquefied gas transfer line having one end connected to the bunkering tank 10 and the other end connected to the manifold 20 is provided so that the liquefied gas can flow. The liquefied gas transfer line may include a liquid transfer line (L10), a gaseous transfer line (L20), and a spray line (L11).

Hereinafter, the liquid transfer line (L10) and the gaseous transfer line (L20) are based on the loading process of supplying the liquefied gas from the bunkering vessel to the liquefied gas storage tank of the target. line for The spray line L11 may mean a line for communicating liquid liquefied gas, but the flow rate of the communicating liquefied gas may be lower than that of the liquid transfer line L10. Hereinafter, the liquid transfer line L10 may encompass both the liquid transfer line L10 and the spray line L11, and may mean at least one or more of the liquid transfer line L10 and the spray line L11. there is. However, these transfer lines are not necessarily for communicating only liquid or gaseous liquefied gas, and as will be described later, liquefied gas or dry gas or inert gas other than liquefied gas may communicate.

A first pump 11 and a second pump 12 may be provided in the bunkering tank 10 . Although not shown, the first pump 11 may be provided at the lower end of the pump tower, and may be installed to be submerged in liquefied gas. The first pump 11 may be installed to be spaced apart from the bottom inside the bunkering tank 10 . The liquefied gas drawn by the first pump 11 may be supplied to a manifold 20 to be described later through a liquefied gas transfer line. Specifically, the liquefied gas drawn out by the first pump 11 may be supplied to the manifold 20 through the liquid phase transfer line L10. The liquid transfer line L10 may be provided with a return line (not shown) capable of returning the withdrawn liquefied gas back to the bunkering tank 10 .

The second pump 12 is provided inside the bunkering tank 10 and may be disposed at a relatively lower position than the first pump 11 . The first pump 11 is for processing a relatively larger flow rate than the second pump 12, and may be used for loading and unloading liquefied gas. The second pump 12 is for additionally pumping the liquefied gas remaining in a trace amount inside the bunkering tank 10 after the loading and unloading process, and the liquefied gas located at a height that the first pump 11 cannot process. can be pumped. In addition, the second pump 12 may be utilized to transfer the liquefied gas of the bunkering tank 10 when the bunkering vessel supports the gassing-up process or the cool-down process of the target vessel.

For example, the second pump 12 may be disposed inside a sump (not shown) formed on the bottom of the inside of the bunkering tank 10 . The sump is provided in the shape of a puddle at the bottom of the bunkering tank 10 , and after most of the liquefied gas is withdrawn from the bunkering tank 10 , a small amount of the liquefied gas may be provided in the sump. The second pump 12 may withdraw the liquefied gas accumulated in the sump.

The liquefied gas drawn by the second pump 12 may be supplied to the manifold 20 through the spray line L11. In addition, the spray line (L11) may be connected to the liquid transfer line (L10) to deliver the extracted liquefied gas to the liquid transfer line (L10). In addition, a liquefied gas return line L12 connected to a return line branching from the liquid transfer line L10 may be provided in the spray line L11. By controlling the flow rate of the liquefied gas flowing to the liquefied gas return line (L12), it is possible to adjust the flow rate of the liquefied gas supplied to the liquid transfer line (L10) through the spray line (L11). In addition, a spray return line L13 may be provided in the spray line L11. The spray return line (L13) returns at least a part of the liquefied gas flowing through the spray line (L11) to the inside of the bunkering tank 10, but is provided at the top of the inside of the bunkering tank 10 and can be returned by spraying the liquefied gas there is. The spray return line L13 may lower the temperature inside the bunkering tank 10 by injecting at least a portion of the liquefied gas to the boil-off gas generated inside the bunkering tank 10 .

A vapor transfer line L20 and a vent line L21 may be provided at the upper end of the bunkering tank 10 . The boil-off gas of the liquefied gas generated inside the bunkering tank 10 may be supplied to the manifold 20 through the gas phase transfer line L20 . In addition, the boil-off gas of the liquefied gas generated inside the bunkering tank 10 may be supplied to the vent part 13 to be described later through the vent line L21. The vapor transfer line L20 may supply a portion of the withdrawn BOG to the vent unit 13 . The vent unit 13 may receive liquefied gas or dry gas or inert gas to be described later and discharge it to the outside of the bunkering vessel. The bunkering vessel may supply and discharge at least a portion of the boil-off gas to the vent unit 13 through the gas phase transfer line L20 when the pressure inside the bunkering tank 10 is higher than or equal to a predetermined level.

The manifold 20 may be provided at the bunkering station of the bunkering vessel and connected to the liquefied gas transfer line to flow in and out of the liquefied gas from the bunkering vessel. The bunker station provides a point connected to the object of loading and unloading through a pipe (not shown). The liquefied gas transfer line may be connected to the manifold 20 . The manifold 20 may include a liquid manifold (L, 21) having one end connected to a liquid phase transfer line (L10) and a gas phase manifold (V, 22) having one end connected to a gas phase transfer line (L20). . That is, one end of the spray line L11 may also be connected to the liquid manifolds L and 21 . The other end of each manifold can communicate with the target through a separately provided pipe. The pipe is provided on the loading arm (not shown) and is suitable for communicating cryogenic liquefied gas, and may be connected to the manifold 20 by providing a cryogenic adapter, a cryogenic coupler, and the like.

Although not shown, the bunkering station may be provided with an ESD (Emergency Shut-Down system) connected to the manifold 20 , and monitor the temperature, pressure and flow rate of the liquefied gas communicating through the manifold 20 . A sensor and a valve for controlling the flow rate of the liquefied gas may be provided. The bunkering station may be provided at the top of the bunkering tank 10 in the bunkering vessel. For example, the bunkering station may be disposed above or below the upper deck, and the bunkering tank 10 may be disposed between the bottom of the bunkering vessel and the bunkering station.

A plurality of liquid manifolds 21 and gaseous manifolds 22 may be provided in the manifold 20 , respectively. A plurality of individual manifolds may be provided side by side in the bunkering station. For example, the manifold 20 may be provided with two liquid manifolds 21 and one gas manifold 22 , and one gas manifold 22 between the two liquid manifolds 21 . ) can be placed.

A plurality of manifolds 20 may be provided in a bunkering vessel. For example, the bunkering vessel may include one manifold 20 on its port or starboard side and the other manifold 20 ′ on its stern. The manifold 20 is provided on one side of the bunkering ship and can be connected to a liquefied gas carrier, a propulsion ship, a platform, etc., and the other manifold 20' disposed in the stern provides a structure suitable for connection with other bunkering ships. can do. Each manifold may have the same configuration, but is not limited thereto. When the bunkering vessel has a plurality of manifolds 20, 20', the liquid transfer line L10 is the liquid transfer line 21 of each manifold 20, 20', and the gaseous transfer line L20 is each It may be connected to the vapor transfer line 22 of the manifolds 20 and 20', respectively. It will be understood that the spray line L11 may also be connected to the liquid transfer line 21 of each of the manifolds 20 and 20'. That is, one end of the liquefied gas transfer line may be connected to the bunkering tank 10 , and the other end may be branched and connected to the respective manifolds 20 and 20 ′.

As described above, the liquefied gas transfer line may include a liquid transfer line (L10) and a gaseous transfer line (L20) based on a loading process in which liquefied gas is supplied from a bunkering vessel to a target, and a spray line (L12) may include more. The spray line L12 may have one end connected to the liquid transfer line L10 to deliver liquid liquefied gas, or may be directly connected to the manifolds 20 and 20' to deliver liquefied gas. At this time, the spray line (L12) may be to transfer the liquefied gas of a smaller flow rate compared to the liquid transfer line (L10).

The liquefied gas transfer line may be connected to the liquefied gas supply lines L14 and L22. Specifically, the liquefied gas supply line (L22) branches from the gaseous transfer line (L20), and the gaseous liquefied gas is converted into a gas combustion unit (GCU), a generator engine (G/E), and a buffer to be described later. At least one of the tanks 40 may be supplied. Gas combustion unit (GCU) can be treated by burning liquefied gas and then discharging it to the outside of the bunkering vessel. The power generation engine (G/E) can generate electricity by using liquefied gas as fuel. Preferably, the power generation engine (G/E) may use gaseous liquefied gas as fuel. The buffer tank 40 may temporarily store liquefied gas and supply it to a place in need thereof, and may be to temporarily store liquefied gas in the gas phase. The buffer tank 40 may separate the supplied liquefied gas into a liquid phase and a gas phase and withdraw the supplied liquefied gas.

In addition, the liquefied gas supply line (L14) may branch from at least one of the liquid transfer line (L10) and the spray line (L11) to vaporize the liquid liquefied gas and then deliver it to the liquefied gas supply line (L22). The liquefied gas supply line L14 may include a forced vaporizer 14 to vaporize the liquid liquefied gas and deliver it to the liquefied gas supply line L22.

The liquefied gas supply line (L22) is supplied with gaseous liquefied gas from the liquefied gas transfer line, and then branches again to at least one of the gas combustion unit (GCU), the power generation engine (G/E) and the buffer tank 40 . It can be supplied by the supplier. Specifically, the gas combustion unit (GCU), the power generation engine (G/E), and the buffer tank 40 may have different gas temperature and pressure conditions required for each. A plurality of liquefied gas supply lines (L22) may be provided in parallel, and one liquefied gas supply line (L22) is an LD (Low-Duty) compressor (17), and the other liquefied gas supply line (L22) ) may include a high-duty (HD) compressor 18 . The liquefied gas supply line L22 may be supplied to the supplier through any one of the compressors according to the type of the supplier and the required conditions accordingly.

The liquefied gas supply line L22 may further include a gas-liquid separator 16 . The gas-liquid separator 16 separates the liquefied gas supplied from the liquefied gas transfer line into a gaseous phase and a liquid phase, and only the gaseous liquefied gas passes through the liquefied gas supply line L22 to the gas combustion unit (GCU) and the power generation engine (G/E). ) and at least one of the buffer tank 40 may be supplied. The liquid phase separated in the gas-liquid separator 16 is a condensate formed by condensing at least a portion of the liquefied gas in the gas phase, and may be returned to the bunkering tank 10 through the condensate return line L23. Preferably, the gas-liquid separator 16 may be provided in front of the LD compressor 17 .

The liquefied gas supply line L22 may further include a heater 19 . The heater 19 may additionally heat the liquefied gas supplied from the liquefied gas supply line L22 and supply it to at least one of the gas combustion unit, the power generation engine G/E, and the buffer tank 40 . The temperature of the liquefied gas increases while being pressurized by the compressors 17 and 18, but may be lower than the temperature required by the above-mentioned supplier. The heater 19 may further heat the liquefied gas to adjust the temperature level required by the supplier. Preferably, the heater 19 may be provided at the rear end of the HD compressor 18 .

Referring to the drawings, for example, the liquefied gas supply line (L22) branches from the gas phase transfer line (L20), and may be provided to branch again into a plurality of liquefied gas supply lines (L22). A gas-liquid separator 16 and an LD compressor 17 may be provided in any one liquefied gas supply line L22, and a gas combustion unit (GCU), a power generation engine (G/E), and a buffer by transferring gaseous liquefied gas At least one of the tanks 40 may be supplied. At this time, the liquefied gas supply line L14 joins at the front end of the gas-liquid separator 16 to receive gaseous liquefied gas and supply it to the gas-liquid separator 16 . An HD compressor 18 and a heater 19 may be provided in the other liquefied gas supply line L22, and the heated gaseous liquefied gas is transported among the gas combustion unit (GCU) and the power generation engine (G/E). At least one can be supplied.

The bunkering vessel may include a gas supply unit 30 . The gas supply unit 30 may supply gas to the target liquefied gas storage tank through the manifold 20 . The gas in the gas supply unit 30 may be at least one of a dry gas and an inert gas, and the gas supply unit 30 may be to produce at least one of the dry gas and the inert gas and supply it to the target.

The gas supply line L30 may have one end connected to the gas supply unit 30 and the other end connected to the liquefied gas transfer line to communicate gas. The gas supply line L30 may be connected to at least one of the liquid transfer line L10 , the gaseous transfer line L20 , and the spray line L11 to deliver the gas supplied from the gas supply unit 30 . Preferably, the gas supply line (L30) may be connected to at least one of the liquid transfer line (L10) and the gaseous transfer line (L20). The gas produced by the gas supply unit 30 may be delivered to the manifold 20 through the gas supply line L30 and the liquefied gas transfer line, and to be supplied to the target liquefied gas storage tank through the manifold 20. can

The bunkering vessel may include a buffer tank 40 . The buffer tank 40 is provided separately from the bunkering tank 10 and may be utilized in the loading and unloading process using the bunkering vessel. The buffer tank 40 is provided in the form of a pressure vessel to store contents at a relatively high pressure compared to the bunkering tank 10 .

A pump 41 may be provided in the buffer tank 40 . The pump 41 may be installed inside the buffer tank 40 to withdraw liquefied gas. The liquefied gas drawn out by the pump 41 may be supplied to the liquefied gas transfer line. For example, the liquid liquefied gas drawn out from the buffer tank 40 may be supplied to at least one of the bunkering tank 10 and the manifold 20 through the liquid transfer line L10 . At this time, at least a portion of the withdrawn liquefied gas may be returned in a manner similar to the spray return line L13 and sprayed into the buffer tank 40 .

In addition, a buffer tank supply line L40 may be provided in the buffer tank 40 . The buffer tank supply line (L40) has one end connected to the liquefied gas supply line (L22) and the other end connected to the inside of the buffer tank (40), so that the liquefied gas supplied from the liquefied gas supply line (L22) is transferred to the buffer tank (40). ) can be passed as The buffer tank supply line L40 may be installed to supply liquefied gas from the lower end of the buffer tank 40 . When liquid liquefied gas exists in the buffer tank 40, the liquefied gas delivered through the buffer tank supply line L40 is supplied from the liquid liquefied gas and is condensed or liquefied by the cooling and heat of the liquid liquefied gas. can

In addition, the buffer tank 40 may be provided with a buffer tank withdrawal line L41. One end of the buffer tank withdrawal line L41 is provided at the upper end of the buffer tank 40 to withdraw the liquefied gas inside the buffer tank 40 . The other end of the buffer tank withdrawal line L41 may be connected to the vapor transfer line L20. In this case, the boil-off gas generated inside the buffer tank 40 is withdrawn through the buffer tank withdrawal line L41 to be able to flow through the gas phase transfer line L20. Alternatively, the buffer tank withdrawal line L41 may be provided so that the other end is connected to the liquefied gas supply line L22. BOG generated inside the buffer tank 40 is withdrawn through the buffer tank withdrawal line L41, and through the liquefied gas supply line L22, the gas combustion unit (GCU), the power generation engine (G/E) and the buffer tank ( 40) can be supplied as at least one of.

Although not shown, an agitator may be provided inside the buffer tank 40 . The liquefied gas supplied to the buffer tank 40 may be condensed or liquefied inside the buffer tank 40 . A temperature difference between the upper end and the lower end inside the buffer tank 40 may occur over time. The agitator ensures uniform mixing of the fluid inside the buffer tank 40 to prevent condensation or a decrease in liquefaction efficiency inside the buffer tank 40 .

Although not shown, the bunkering vessel may include at least one of a liquefied gas re-liquefaction system and an auxiliary boiler instead of the buffer tank 40 . Alternatively, the bunkering vessel may include at least one of a buffer tank 40 , a reliquefaction system, and an auxiliary boiler. The re-liquefaction system may receive and liquefy gaseous liquefied gas generated during the bunkering process and then supply it to the bunkering tank 10 . The auxiliary boiler may generate steam by receiving and burning gaseous liquefied gas generated during the bunkering process, and may supply the generated steam to a steam demander of the bunkering vessel.

The bunkering vessel according to the present embodiment as described above includes a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a gas supply unit 30, a buffer tank 40, and the like to load the target liquefied gas. and an unloading process.

Hereinafter, a process of loading and unloading using a bunkering vessel according to an embodiment of the present invention will be described in more detail. Prior to this, the overall process of loading and unloading liquefied gas to a target using a bunkering vessel will be described.

The bunkering vessel may store liquefied gas for loading into the liquefied gas storage tank of the target in the bunkering tank 10 . The bunkering vessel may also be supplied with liquefied gas from an initial onshore or offshore platform or other bunkering vessel.

The bunkering vessel may operate in a state in which liquefied gas is stored in the bunkering tank 10 or may drive other facilities in the vessel. That is, the bunkering vessel may use liquefied gas as fuel even before bunkering, and may drive a power generation engine (G/E) and the like. In addition, liquefied gas may be evaporated inside the bunkering tank 10 to generate boil-off gas, and it may be necessary to process the boil-off gas for internal pressure management of the bunkering tank 10 . Therefore, the bunkering vessel can use liquefied gas as fuel even before bunkering. Preferably, the bunkering can use liquefied gas in the gas phase as a fuel. This gas treatment process is a gas firing process.

The gas combustion process may include extracting boil-off gas generated in the bunkering tank 10 and supplying it to the power generation engine (G/E) or the like. In this case, the BOG generated in the bunkering tank 10 may vary depending on the environment in which the bunkering vessel is located or whether the bunkering vessel operates. When the flow rate of boil-off gas generated in the bunker tank 10 is less than the flow rate of liquefied gas required by the power generation engine (G/E), etc. . The gas combustion process may be performed not only before bunkering, but also in all other processes in which liquefied gas is present in the bunkering tank 10 . A detailed description of the gas combustion process will be described later with reference to FIG. 2 .

The bunkering vessel may be connected to the target to perform the bunkering process, and may receive BOG from the target prior to loading or unloading and process it. The bunkering vessel may receive the boil-off gas generated in the liquefied gas storage tank of the target through the manifold 20 and supply it to at least one of the gas combustion unit (GCU) and the buffer tank 40 to be processed. This treatment process is a boil-off gas treatment (BOG treatment) process. A detailed description of the BOG treatment process will be described later with reference to FIG. 3 .

The bunkering vessel may supply at least one of dry gas and inert gas or nitrogen gas to the liquefied gas storage tank before loading the liquefied gas into the target liquefied gas storage tank. The bunkering vessel may supply the gas generated by the gas supply unit 30 to the liquefied gas storage tank so that the internal environment of the liquefied gas storage tank meets the environmental conditions necessary for loading. The process of supplying the dry gas is drying, and the process of supplying the inert gas is inerting.

The drying process is to remove moisture inside the liquefied gas storage tank by injecting dry gas, which is air that does not contain moisture, into the liquefied gas storage tank. The drying process may be largely divided into two types depending on the temperature condition in which the process is performed. For example, the drying process may be divided into those performed under a relatively low temperature condition such as winter and performed under a relatively high temperature condition such as summer.

The inerting process may be performed after the drying process, and an inert gas is injected into the liquefied gas storage tank to remove the dry gas filled in the liquefied gas storage tank. The inerting process may be largely divided into two types according to the type of inert gas used in the process. Hereinafter, the inert gas refers to both an inert gas and a nitrogen gas generated by burning heavy oil. For example, the inerting process may be divided into one performed using a gas generated by burning heavy oil and one performed using nitrogen gas. Specific details of the drying and inerting process will be described later with reference to FIGS. 4 and 5 .

The bunkering vessel may supply a relatively small flow rate of liquefied gas to the liquefied gas storage tank before loading the liquefied gas into the target liquefied gas storage tank. The bunkering vessel may withdraw some of the liquid liquefied gas stored in the bunkering tank 10 and supply it to the liquefied gas storage tank. This liquefied gas supply process is gassing up.

The gasing-up process may be performed by being divided into a plurality of steps according to the environmental conditions inside the liquefied gas storage tank. In addition, the gasing-up process may be divided into a process of supplying liquefied gas in a liquid phase or vaporizing liquefied gas in a bunkering vessel and then supplying the liquefied gas according to the conditions of the target to be supplied with the liquefied gas. The gasing-up process may be performed after drying or inerting, and the gassing-up process is to inject liquefied gas into a liquefied gas storage tank to remove dry gas and inert gas filled in the liquefied gas storage tank. Specific details of the gassing-up process will be described later with reference to FIGS. 6 to 9 .

The bunkering vessel may additionally supply a relatively small flow of liquefied gas to the liquefied gas storage tank before loading the liquefied gas into the target liquefied gas storage tank. This liquefied gas supply process is a cool down (Cooling down).

The cool-down process makes the inside of the liquefied gas storage tank in a low temperature state to prevent the formation of BOG when loading the liquefied gas or to reduce BOG generation. The cool-down process may be performed after gassing up, and the internal temperature of the liquefied gas storage tank may be lowered by injecting low-temperature liquefied gas into the liquefied gas storage tank. The specific details of the cool-down process will be described later with reference to FIG. 10 .

The bunkering vessel may load the liquefied gas into the target liquefied gas storage tank after the cool-down process. The bunkering vessel can supply the liquid liquefied gas to the target liquefied gas storage tank and at the same time receive the low-temperature liquefied gas that has been filled in the liquefied gas storage tank. Details of the loading process will be described later with reference to FIG. 11 .

The bunkering vessel can further process gases generated during loading, unloading and cool-down processes. The gas may be boil-off gas, and similarly to the above-described gas combustion process, it may be supplied to a power generation engine (G/E) and the like to be combusted and processed. This gas treatment process is also a gas combustion process. Details of the gas combustion process after bunkering will be described later with reference to FIG. 12 .

The bunkering vessel may unload liquefied gas from the target's liquefied gas storage tank in a manner opposite to loading. The bunkering vessel can increase the temperature inside the liquefied gas storage tank by supplying the liquefied gas to the liquefied gas storage tank after unloading. The supply process of such liquefied gas is a warming-up.

In the warm-up process, a relatively high temperature liquefied gas may be injected into the liquefied gas storage tank to discharge the liquefied gas remaining in the liquefied gas storage tank. The warm-up process may be performed after unloading, and the vaporized liquefied gas may be supplied to the target liquefied gas storage tank, and the remaining liquefied gas that is not unloaded from the liquefied gas storage tank may be vaporized and discharged. The exhaust gas discharged at this time can be supplied and treated by the bunkering vessel. In addition, the warm-up process may be divided into a process in which the bunkering vessel receives a relatively low temperature liquefied gas and a process in which a relatively high temperature liquefied gas is supplied according to the condition of the exhaust gas supplied from the target liquefied gas storage tank. Details of the warm-up process will be described later with reference to FIGS. 13 and 14 .

The bunkering vessel can supply inert gas to the target liquefied gas storage tank after warming up. The process of supplying inert gas after unloading is gas freeing.

In the gas freeing process, an inert gas may be injected into the target liquefied gas storage tank to discharge the liquefied gas in the liquefied gas storage tank. The exhaust gas discharged at this time can be supplied and treated by the bunkering vessel. A detailed description of the gas freeing process will be described later with reference to FIG. 15 .

The bunkering vessel may supply dry gas to the target liquefied gas storage tank after gas freeing. The process of supplying dry gas after gas freeing is aerating.

In the aerating process, the inert gas in the liquefied gas storage tank may be discharged by injecting the dry gas into the target liquefied gas storage tank. Details of the aerating process will be described later with reference to FIGS. 16 and 17 .

Hereinafter, an individual process of loading and unloading using a bunkering vessel according to an embodiment of the present invention will be described in more detail with reference to FIGS. 2 to 17 . In FIGS. 2 to 17 , it will be understood that the liquefied gas is not limited to a specific type as illustrated by exemplifying the case where the liquefied gas is liquefied natural gas.

2 is a conceptual diagram illustrating a gas combustion process before bunkering in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a buffer tank 40, and the like, and the same content as described in FIG. 1 is replaced with the description of the previous embodiment decide to do

The bunkering vessel according to the present embodiment may further include a power generation engine (G/E) for generating electric power by using liquefied gas as a fuel. The bunkering vessel can produce electricity by supplying the liquefied gas drawn through the liquefied gas transfer line to the power generation engine G/E through the liquefied gas supply lines L14 and L22 and burning it.

The bunkering vessel may receive liquefied gas for loading from the outside before bunkering, that is, before loading the liquefied gas on the target and store it in the bunkering tank 10 . The bunkering vessel may receive liquefied gas from the outside through the manifold 20 . The bunkering vessel may be supplied with liquefied gas in the liquid phase through the liquid manifold 21 , and may return the liquefied gas in the gas phase at the same time through the vapor manifold 22 . The liquid manifold 21 may supply liquid liquefied gas to the bunkering tank 10 through at least one of the liquid transfer line L10 and the spray line L11, and the gaseous manifold 22 is a vapor transfer line ( L20) through the gas phase liquefied gas may be supplied to the bunkering tank (10).

The liquefied gas stored in the bunkering tank 10 may be withdrawn again through at least one of a liquid transfer line L10 , a spray line L11 , and a gaseous transfer line L20 . Although not shown, the bunkering vessel withdraws the liquid liquefied gas stored in the bunkering tank 10 through at least one of the liquid transfer line L10 and the spray line L11 and delivers it to the liquefied gas supply line L14, and bunkering The boil-off gas of the liquefied gas generated inside the tank 10 may be withdrawn through the gaseous transfer line L20 and delivered to the liquefied gas supply line L22.

The bunkering vessel may preferentially withdraw the boil-off gas generated in the bunkering tank 10 and supply it to the liquefied gas supply line L22. Accordingly, the pressure inside the bunkering tank 10 may be maintained constant or within a safe range. The power generation engine (G/E) can generate electricity used in bunkering ships. The flow rate of BOG generated inside the bunkering tank 10 may vary depending on the temperature of the place where the bunkering vessel is located, the operating speed of the bunkering vessel, and the temperature and pressure conditions inside the bunkering tank 10 . The flow rate of BOG generated inside the bunkering tank 10 may be relatively small compared to the flow rate required by the power generation engine (G/E). The bunkering vessel may additionally withdraw some of the liquid liquefied gas stored in the bunkering tank 10 and supply it through the liquefied gas supply line L14 to satisfy the demand of the power generation engine G/E.

For example, the bunkering vessel may withdraw BOG through the vapor transfer line L20 and supply it to the power generation engine G/E through the liquefied gas supply line L22 branching from the vapor transfer line L20. In addition, the bunkering vessel withdraws liquid liquefied gas through at least one of the liquid transfer line (L10) and the spray line (L11), and branches the liquefied gas supply line (L14) from the liquid transfer line (L10) or the spray line (L11) ) through the power generation engine (G/E). More specifically, a forced vaporizer 14 may be provided on the liquefied gas supply line L14, and the forced vaporizer 14 vaporizes liquid liquefied gas to supply the vaporized liquefied gas to the liquefied gas supply line L22. can

The forced vaporizer 14 may vaporize the liquefied gas using a heat source existing inside the bunkering vessel. The heat source may be seawater, fresh water used inside the bunkering vessel, steam, or engine exhaust gas generated inside the bunkering vessel, but the type is not limited and may be anything that can vaporize cryogenic liquefied gas.

The forced vaporized liquefied gas and boil-off gas may be supplied to the gas-liquid separator 16 provided on the liquefied gas supply line L22 by joining in the liquefied gas supply line L22. The gas-liquid separator 16 may temporarily store the supplied liquefied gas, and may be provided in the form of a mist separator or a buffer tank. The gas-liquid separator 16 separates the supplied liquefied gas into a gaseous phase and a liquid phase to supply only the gaseous liquefied gas through the liquefied gas supply line L22. When the liquefied gas is liquefied natural gas, for example, the liquefied gas may further include relatively heavy heavy carbon such as ethane and propane as well as methane. The gas-liquid separator 16 may form a condensate by condensing a portion of the liquefied gas and the heavy carbon contained in the liquefied gas, and the formed condensate is delivered to the bunkering tank 10 through the condensate return line L23. can

The gaseous liquefied gas supplied from the gas-liquid separator 16 may be supplied by being pressurized by the LD compressor 17 to a pressure required by the power generation engine G/E. The liquefied gas pressurized by the LD compressor 17 may be heated to a temperature required by the power generation engine G/E, but may be in a relatively high temperature state compared to the required temperature. For example, when the liquefied gas is liquefied natural gas, the liquefied gas flowing at the front end of the LD compressor 17 may be natural gas in a relatively low temperature state as boil-off gas, and the liquefied gas at the rear end of the LD compressor 17 is relatively It may be natural gas in a high temperature state.

Although not shown, a plurality of LD compressors 17 may be provided in series or in parallel. The LD compressor 17 may be provided with a cooler for cooling the pressurized liquefied gas at its rear end. The cooler may supply the liquefied gas to the power generation engine (G/E) by cooling it to a temperature required by the power generation engine (G/E). A recirculation line (not shown) for one or more LD compressors 17 may be provided on the liquefied gas supply line L22 . Alternatively, the recirculation line may be provided inside the LD compressor 17 . The recirculation line can match the pressure and flow rate of the liquefied gas discharged from the rear end of the LD compressor 17 to the needs of the power generation engine (G/E).

The gas combustion process as described above has been described as being performed before bunkering in a bunkering vessel, but is not limited thereto. When liquefied gas exists in the bunkering tank 10 of the bunkering vessel, the gas combustion process according to the present embodiment may be performed in parallel in other processes below. That is, although the gas combustion process according to the present embodiment is not illustrated in FIGS. 3 to 17 , it will be understood that the gas combustion process may be performed at the same time as the process performed for each drawing.

3 is a conceptual diagram illustrating a BOG treatment process before bunkering in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a buffer tank 40, and the like, and the same content as described in FIG. 1 is replaced with the description of the previous embodiment decide to do

The bunkering vessel according to the present embodiment may receive and process boil-off gas generated in the liquefied gas storage tank of the target while the bunkering vessel is connected to the target. Preferably, the bunkering vessel may receive and process boil-off gas generated in the target liquefied gas storage tank before unloading. For example, when the liquefied gas is liquefied natural gas, the bunkering vessel may be supplied with natural gas in a relatively low temperature state as boil-off gas of the liquefied natural gas through the gas phase manifold 22 .

The bunkering vessel may be supplied with boil-off gas through the gaseous manifold 22 of the manifolds 20 and 20'. The bunkering vessel may transfer the boil-off gas supplied through the gaseous phase manifold 22 to the liquefied gas supply line L22 through the gaseous transfer line L20.

In this embodiment, a plurality of liquefied gas supply lines L22 may be provided in parallel. For example, one liquefied gas supply line L22 may include a gas-liquid separator 16 and an LD compressor 17 , and the other liquefied gas supply line may include an HD compressor 18 and a heater 19 . there is. The bunkering vessel may supply boil-off gas supplied through the gaseous phase manifold 22 to a plurality of liquefied gas supply lines L22, respectively, and process it.

In this embodiment, the bunkering vessel may process the supplied boil-off gas using at least one of the gas combustion unit (GCU) and the buffer tank 40 .

For example, BOG is delivered to a liquefied gas supply line L22 having an HD compressor 18 and a heater 19, and the liquefied gas supply line L22 receives BOG supplied to a gas combustion unit (GCU). can be supplied with BOG is pressurized by the HD compressor 18 and further heated by the heater 19 to have the temperature and pressure required by the gas combustion unit (GCU), and the gas combustion unit (GCU) burns the BOG to external can be disposed of by discharging.

For example, BOG is delivered to a liquefied gas supply line L22 having a gas-liquid separator 16 and an LD compressor 17 through a gas phase transfer line L20, and the liquefied gas supply line L22 is BOG may be supplied to the buffer tank 40 . Separation of liquefied gas and condensate in the gas phase through the gas-liquid separator 16 is replaced by the above-described embodiment. The liquefied gas in the gas phase separated by the gas-liquid separator 16 may be supplied to the buffer tank 40 by going through the LD compressor 17 to a relatively high temperature state.

The buffer tank 40 may temporarily store at least a portion of the pressurized liquefied gas. The buffer tank 40 may receive gaseous liquefied gas through the buffer tank supply line L40. As the gaseous liquefied gas flows into the relatively bulky buffer tank 40, it expands and at least part of it may be liquefied. Alternatively, the gaseous liquefied gas may be cooled by the low-temperature liquefied gas previously stored in the buffer tank 40 so that at least a part thereof is condensed or liquefied. The buffer tank 40 may supply liquid liquefied gas to the bunkering tank 10 using the pump 41 .

In the boil-off gas treatment process according to the present embodiment, the target may be a liquefied gas carrier or a liquefied gas propulsion ship, and the liquefied gas storage tank may be a pressure vessel, but is not limited thereto. In addition, in addition to receiving and processing boil-off gas through the gaseous phase manifold 22, the gaseous transfer line L20 also receives the boil-off gas generated inside the bunkering tank 10 of the bunkering vessel and can be processed in the same way. there is.

The BOG treatment process as described above has been described as being performed before unloading in the bunkering vessel, but is not limited thereto. The bunkering vessel according to this embodiment uses a gas combustion unit (GCU) and a buffer tank 40 provided in the bunkering vessel to process BOG generated in the liquefied gas storage tank of the target, so that BOG in the target At the same time, the bunkering process can be smoothly and safely performed by simplifying the facility for processing and controlling the pressure inside the target liquefied gas storage tank before bunkering.

4 and 5 are conceptual views illustrating the drying and inerting process before bunkering in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a gas supply unit 30, and the like, and the same content as described in FIG. 1 is replaced with the description of the previous embodiment decide to do

The bunkering vessel according to this embodiment may supply at least one of a dry gas and an inert gas to the liquefied gas storage tank of the target in a state in which the bunkering vessel is connected to the target.

First, an embodiment of the drying process for supplying the drying gas will be described. In the drying process, before loading the liquefied gas into the liquefied gas storage tank of the target, the drying gas is supplied to the liquefied gas storage tank of the target through the manifolds 20 and 20' to remove moisture inside the liquefied gas storage tank. it could be

The liquefied gas storage tank before the liquefied gas loading may be in a state full of air. The air has an oxygen concentration of about 20% (v/v) and may have the same composition as that of the general atmosphere including a trace amount of water vapor. The water contained in the air is a very small amount compared to oxygen or nitrogen, and may be in the form of small water droplets or water vapor, but when the cryogenic liquefied gas is loaded, it solidifies inside the liquefied gas storage tank and is provided inside the liquefied gas storage tank or liquefied gas storage tank It can damage components such as pumps. It is possible to protect the liquefied gas storage tank and other facilities by removing the moisture inside the liquefied gas storage tank through the drying process.

The gas supply unit 30 may be a dry gas supply unit, and the dry gas may be nitrogen gas or dry air that does not contain moisture. The dry gas supply unit may be to produce dry gas by using electric power produced by the power generation engine (G/E) of the bunkering vessel.

The dry gas supply unit may produce dry gas and supply the dry gas to the target liquefied gas storage tank through the gas supply line L30. Since the drying process is performed before loading, the drying gas supply unit may supply the drying gas through the liquefied gas transfer line and the manifolds 20 and 20'. The gas supply line L30 may supply dry gas to the manifolds 20 and 20' through at least one of the liquid transfer line L10, the gaseous transfer line L20, and the spray line L11.

In this case, the gas supply line L30 may supply dry gas through the liquid transfer line L10 or the gaseous transfer line L20 according to the external temperature of the bunkering vessel or the internal temperature of the target liquefied gas storage tank. Alternatively, the gas supply line L30 may supply dry gas through the liquid transfer line L10 or the gaseous transfer line L20 according to a difference in specific gravity between the gas supplied to the bunkering vessel and the gas inside the bunkering vessel. In the bunkering vessel, the manifolds 20 and 20' at the bunkering station may be connected to the target liquefied gas storage tank through a pipe including an insulating material, but it is affected by the external temperature of the bunkering vessel. Accordingly, even when a heat insulating material is provided in the pipe, the gas moving through the pipe may be heated by receiving heat from the external environment.

The bunkering vessel may supply the dry gas through the liquid manifold 21 or the gaseous manifold 22 in consideration of these temperature conditions or specific gravity conditions. It should be noted that each manifold is named based on the process of loading and unloading liquefied gas. The liquid manifold 21 may be connected to the liquid transfer line (not shown) connected to the target liquefied gas storage tank as well as the liquid transfer line L10 provided in the bunkering vessel through or without a pipe. One end of the liquid transfer line in the target may be provided at the lower end of the liquefied gas storage tank in the same way as the liquid transfer line (L10) provided in the bunkering vessel. The gaseous phase manifold 22 may be connected to the gaseous phase transfer line L20 provided in the bunkering vessel as well as the gaseous phase transfer line (not shown) connected to the liquefied gas storage tank of the target through or without a pipe. In the same way as the gaseous transfer line L20 provided in the bunkering vessel, one end may be provided at the upper end of the liquefied gas storage tank.

Referring to FIG. 4 as an embodiment according to the present invention, the gas supply line L30 may supply dry gas through the liquid phase transfer line L10 when the external temperature of the bunkering vessel is above a predetermined temperature. The predetermined temperature may be an external temperature capable of causing the temperature inside the target liquefied gas storage tank to be higher than the temperature of the dry gas injected into the liquefied gas storage tank through the manifolds 20 and 20'. Here, the predetermined temperature may be approximately 20 to 40 ℃, but is not limited thereto and may vary depending on the season or region. For example, in summer, the temperature inside the target liquefied gas storage tank may be relatively high, and the bunkering vessel may supply dry gas through the liquid transfer line L10. The gas supply line L30 may supply dry gas to the lower end of the liquefied gas storage tank through the liquid manifold 21 through the liquid phase transfer line L10. Dry gas, which has a relatively lower temperature than the temperature inside the liquefied gas storage tank, may have a heavier weight than the air in the liquefied gas storage tank, and is supplied to the lower end of the liquefied gas storage tank. It is possible to push air to the top of the liquefied gas storage tank. Similarly, the gas supply line (L30) may supply dry gas through the liquid transfer line (L10) when the internal temperature of the target liquefied gas storage tank is higher than a predetermined temperature.

Referring to FIG. 5 , the gas supply line L30 may supply dry gas through the gas phase transfer line L20 when the external temperature of the bunkering vessel is lower than a predetermined temperature. For example, in winter, the temperature inside the target liquefied gas storage tank may be relatively low, and the bunkering vessel may supply dry gas through the gas phase transfer line L20. The gas supply line L30 may supply dry gas to the upper end of the liquefied gas storage tank through the gas phase manifold 22 through the gas phase transfer line L20. Dry gas having a relatively higher temperature than the internal temperature of the liquefied gas storage tank may have a lighter weight than the air in the liquefied gas storage tank, and is supplied to the top of the liquefied gas storage tank and descends to the bottom of the liquefied gas storage tank. It is possible to push the air inside the liquefied gas storage tank to the lower end of the liquefied gas storage tank.

Regardless of the drying gas supply method, the drying gas supply unit may supply the drying gas until the dew point inside the liquefied gas storage tank is lower than -20°C. When the dew point inside the liquefied gas storage tank is lower than -20℃, the liquefied gas storage tank may contain less than 1 g of moisture per 1 m ³ , and the effect on the loading of liquefied gas in the corresponding moisture content range can be minimized. there is.

In the boil-off gas processing process according to this embodiment, the target may be a liquefied gas carrier or a liquefied gas propulsion ship. The liquefied gas storage tank of the object may be a pressure vessel, but is not limited thereto.

The bunkering vessel according to this embodiment may adjust the supply position of the dry gas in the liquefied gas storage tank in consideration of the temperature condition or specific gravity condition inside the dry gas supplied from the bunkering vessel and the target liquefied gas storage tank. When the dry gas is relatively high temperature, it is injected from the top of the liquefied gas storage tank to push the internal air to the bottom, and when the dry gas is relatively low, it is liquefied using the piston effect that injects it from the bottom of the liquefied gas storage tank and pushes the internal air to the top. Moisture inside the gas storage tank can be removed more effectively.

An embodiment of an inerting process for supplying an inert gas will be described with reference to FIGS. 4 and 5 . The inerting process is to remove the explosive gas inside the liquefied gas storage tank by supplying the inert gas to the liquefied gas storage tank through the manifolds 20 and 20' before loading the liquefied gas into the liquefied gas storage tank of the target. can Preferably, the inerting process may be to remove the dry gas injected into the liquefied gas storage tank after the drying process. Hereinafter, the explosive gas means a gas that can induce a combustion reaction in which the liquefied gas is used as a combustible material when the liquefied gas is loaded, including oxygen.

The liquefied gas storage tank that has undergone the drying process may be in a state full of dry gas. When the dry gas is dry air, the dry air may have an oxygen concentration of about 20% (v/v). In addition, the dry air may contain a very small amount of moisture. Through the inerting process, the oxygen concentration in the liquefied gas storage tank is reduced to a safe level, and water is additionally removed to ensure safety in the bunkering process.

The gas supply unit 30 may be an inert gas supply unit, and the inert gas may be a gas generated by burning nitrogen gas or heavy oil. The inert gas supply unit may be at least one of a nitrogen generator generating nitrogen gas and an inert gas generator (IGG) capable of burning heavy oil.

When the inert gas supply unit is a nitrogen gas generator, the inert gas supply unit separates nitrogen gas using a difference in partial pressure of each component in the air using a separation membrane, or pressure swing adsorption (PSA) using an adsorption tower. Absortion) may be to separate nitrogen gas. In the separation process of nitrogen gas, nitrogen gas may be separated and supplied at a low temperature of approximately -30°C.

When the inert gas supply unit is an inert gas generator capable of burning heavy oil, the inert gas supply unit additionally burns exhaust gas discharged from an engine using heavy oil as fuel, or directly burns heavy oil to generate inert gas. it could be In the present invention, the engine may be a propulsion engine using heavy oil, and the heavy oil may be at least one of Heavy Fuel Oil (HFO), Marine Diesel Oil (MDO), and Marine Gas Oil (MGO), but is not limited thereto. .

The inert gas supplied from the inert gas supply unit may have an oxygen concentration of 5% (v/v) or less, preferably an oxygen concentration of 2% (v/v) or less, and most preferably an oxygen concentration of 1 % (v/v) or less.

The inert gas supply unit may be to produce an inert gas using electric power produced by the power generation engine (G/E) of the bunkering vessel.

The inert gas supply unit may produce an inert gas and supply the inert gas to the liquefied gas storage tank through the gas supply line L30. Since the inerting process is performed before loading, the inert gas supply unit may supply the inert gas through the liquefied gas transfer line and the manifolds 20 and 20'. The gas supply line L30 may supply an inert gas to the manifolds 20 and 20 ′ through at least one of the liquid transfer line L10 , the gaseous transfer line L20 , and the spray line L11 .

At this time, the gas supply line L30 may supply the dry gas through the liquid transfer line L10 or the gaseous transfer line L20 according to the type of the inert gas.

Referring to FIG. 4 , the gas supply line L30 may supply the inert gas through the liquid transfer line L10 if the inert gas supplied from the inert gas supply unit is a gas generated by burning heavy oil. When the inert gas is a gas generated by burning heavy oil, the inert gas may be heavier than the gas inside the target liquefied gas storage tank. The gas supply line L30 may supply an inert gas to the lower end of the target liquefied gas storage tank through the liquid manifold 21 through the liquid phase transfer line L10. Relatively heavy inert gas is supplied to the lower end of the liquefied gas storage tank to push the dry gas in the liquefied gas storage tank to the upper end of the liquefied gas storage tank.

Referring to FIG. 5 , the gas supply line L30 may supply the inert gas through the gas phase transfer line L20 when the inert gas supplied from the inert gas supply unit is nitrogen gas. When the inert gas is nitrogen gas, the inert gas may be lighter than the gas in the target liquefied gas storage tank. The gas supply line L30 may supply an inert gas to the upper end of the target liquefied gas storage tank through the gas phase manifold 22 through the gas phase transfer line L20. The relatively light inert gas is supplied to the upper end of the liquefied gas storage tank and descends to the lower end of the liquefied gas storage tank to push the dry gas in the liquefied gas storage tank to the lower end of the liquefied gas storage tank.

Regardless of the type of inert gas, the inert gas supply unit supplies the inert gas in a state where the dew point inside the target liquefied gas storage tank is lower than -20℃, until the dew point inside the liquefied gas storage tank is lower than -40℃ An inert gas may be supplied. When the dew point inside the liquefied gas storage tank is lower than -40 ℃, the liquefied gas storage tank may contain less than 0.1 g of moisture per 1 m ³ .

In addition, the inert gas supply unit may supply the inert gas until the oxygen concentration in the liquefied gas storage tank is lower than 2% (v/v). When the oxygen concentration in the liquefied gas storage tank is lower than 2% (v/v), the risk of explosion in the liquefied gas storage tank is significantly lowered.

In the boil-off gas processing process according to the present embodiment, the target may be a liquefied gas carrier. The liquefied gas storage tank of the object may be a pressure vessel, but is not limited thereto.

The bunkering vessel according to this embodiment can remove moisture and oxygen in the liquefied gas storage tank by using the inert gas generated inside the bunkering vessel, and the supply position in the liquefied gas storage tank is adjusted according to the characteristics of the inert gas. Thus, it is possible to more effectively remove moisture and oxygen in the liquefied gas storage tank by using the piston effect.

6 and 7 are conceptual views illustrating a gassing-up process before bunkering in a liquefied gas carrier having a liquefied gas vaporizer in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a buffer tank 40, and the like, and the same content as described in FIG. 1 is replaced with the description of the previous embodiment decide to do

The bunkering vessel according to this embodiment may supply liquefied gas to the liquefied gas storage tank of the liquefied gas carrier in a state in which the bunkering vessel is connected to the target, and may receive exhaust gas discharged from the liquefied gas carrier.

Gasing-up process can be divided into a first step and a second step according to the composition of the inside of the liquefied gas storage tank of the liquefied gas carrier. For example, the gasing-up process is a first step of supplying liquefied gas until the concentration of liquefied gas in the gas phase inside the liquefied gas storage tank becomes 5% (v/v), and liquefaction of the gaseous phase inside the liquefied gas storage tank It can be divided into a second step of supplying liquefied gas until the gas concentration exceeds 99% (v/v).

In the gasing-up process, before loading the liquefied gas into the liquefied gas storage tank of the liquefied gas carrier, at least a portion of the liquefied gas is supplied to the liquefied gas storage tank through the manifolds 20 and 20' and stored in the liquefied gas storage tank. It may be to remove the existing gas. Preferably, the gasing-up process may be to remove the inert gas injected into the liquefied gas storage tank after the inerting process. This may be to supply a relatively small flow rate of liquefied gas compared to the flow rate at the time of full-scale loading of the liquefied gas.

The liquefied gas storage tank before the liquefied gas loading may be in a state full of inert gas. The inert gas may contain carbon dioxide. Carbon dioxide contained in the inert gas is then sublimed by the cryogenic liquefied gas as the liquefied gas is loaded, thereby damaging the liquefied gas storage tank or a pump provided inside the liquefied gas storage tank. It is possible to protect the liquefied gas storage tank and other facilities by removing the carbon dioxide inside the liquefied gas storage tank through the gassing-up process.

The bunkering vessel may supply liquefied gas to the liquefied gas storage tank of the liquefied gas carrier by using a liquefied gas transfer line. Since the gassing-up process is performed before loading, the bunkering vessel can supply liquid liquefied gas through the liquefied gas transfer line and the manifolds 20 and 20'. The bunkering vessel may supply liquid liquefied gas to the liquid manifold 21 through at least one of the liquid transfer line L10 and the spray line L11.

More specifically, the bunkering vessel may supply liquid liquefied gas to the liquefied gas vaporizer of the liquefied gas carrier through the liquid manifold 21 . The liquefied gas vaporized in the liquefied gas vaporizer may be injected into the liquefied gas storage tank of the liquefied gas carrier as a gaseous phase. As gaseous liquefied gas is injected into the liquefied gas storage tank, the gas stored in the liquefied gas storage tank may be discharged. Such exhaust gas may be an inert gas, and may be supplied to the bunkering vessel through the gaseous manifold 22 of the bunkering vessel.

The bunkering vessel may receive and process the exhaust gas discharged from the liquefied gas carrier through the gas phase transfer line L20.

Referring to FIG. 6 , in the initial stage of the gassing business, that is, as the liquefied gas is vaporized and injected into the liquefied gas storage tank, most of the exhaust gas discharged from the liquefied gas storage tank is an inert gas, indicating the first stage. Gas phase transfer line (L20) as described above until the concentration of liquefied gas in the gas phase inside the liquefied gas storage tank is 5% (v / v) of the gas combustion unit (GCU) and the vent unit (13) At least one can be supplied. For example, the gaseous transfer line L20 converts the exhaust gas to a gas combustion unit (GCU) when the concentration of the inert gas contained in the exhaust gas is less than or equal to a predetermined value, and when the concentration of the inert gas is greater than or equal to a predetermined value, a vent unit ( 13) can be supplied. The predetermined value may be approximately 95%.

The gaseous transfer line (L20) can be processed by supplying the exhaust gas to the gas combustion unit (GCU) through the liquefied gas supply line (L22). The liquefied gas supply line L22 may be provided with an HD compressor 18 to pressurize the inert gas according to the pressure required by the gas combustion unit (GCU) and then supply it to the gas combustion unit (GCU). Alternatively, the gaseous transfer line L20 may supply the exhaust gas to the vent unit 13 and discharge it to the outside for treatment.

Referring to FIG. 7 , the gaseous transfer line L20 may supply the exhaust gas to at least one of the gas combustion unit (GCU) and the buffer tank 40 when the concentration of the inert gas included in the exhaust gas is less than a predetermined value. . 7 can represent the second stage after the initial gasing up, that is, that most of the exhaust gas discharged from the liquefied gas storage tank is liquefied gas or boil-off gas in the gas phase as the liquefied gas is vaporized and the liquefied gas is injected. The gaseous phase transfer line (L20) converts the exhaust gas to the gas combustion unit (GCU) when the liquefied gas concentration in the gas phase inside the liquefied gas storage tank exceeds 5% (v/v), and the liquefied gas concentration is approximately 90% (v/v) v), it can be supplied to the buffer tank 40 .

Gas phase transfer line (L20) can be processed by supplying exhaust gas to the gas combustion unit (GCU) through the liquefied gas supply line (L22) having the HD compressor (18). Alternatively, the gas phase transfer line L20 may supply the exhaust gas to the buffer tank 40 through the liquefied gas supply line L22 including the LD compressor 17 to be processed. When the exhaust gas is supplied to the buffer tank 40, the condensate component may be separated while the exhaust gas passes through the gas-liquid separator 16 in front of the LD compressor 17. When the capacity of the buffer tank 40 is full, the exhaust gas may be supplied to the gas combustion unit (GCU) and processed.

As the exhaust gas pressurized by the LD compressor 17 expands while being supplied to the buffer tank 40 , at least a portion of the exhaust gas is condensed or liquefied to form a liquid liquefied gas. The buffer tank 40 may supply liquid liquefied gas to the liquid transfer line L10 using the pump 41 , and the liquid liquefied gas is returned to the bunkering tank 10 or returned to the liquid manifold 21 . can be supplied.

The bunkering vessel according to this embodiment supplies liquefied gas to a liquefied gas carrier having a liquefied gas vaporizer, and injects the liquefied gas vaporized in the liquefied gas vaporizer into the liquefied gas storage tank to remove the inert gas inside the liquefied gas storage tank can do. At this time, the treatment method of the exhaust gas discharged from the liquefied gas storage tank can be performed differently depending on the degree of removal of the inert gas, and in the gassing-up process of the second stage with a high content of liquefied gas, the exhaust gas is supplied to the buffer tank. The liquefied gas in the exhaust gas can be reused.

8 and 9 are conceptual views illustrating a gassing-up process before bunkering in a liquefied gas propulsion ship that does not have a liquefied gas vaporizer in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a liquefied gas vaporizer 15, a manifold 20, a liquefied gas transfer line, a buffer tank 40, and the like, and the same content as described in FIG. 1 is the description will be replaced with the contents of the previous embodiment.

The bunkering vessel according to this embodiment may supply liquefied gas to the liquefied gas storage tank of the liquefied gas propulsion vessel in a state in which the bunkering vessel is connected to the target, and may receive exhaust gas discharged from the liquefied gas carrier.

The gassing-up process can be divided into a first step and a second step according to the composition of the inside of the liquefied gas storage tank of the liquefied gas carrier, and the classification criteria for each step are the same as in the above-described embodiment.

In the gasing-up process, before loading the liquefied gas into the liquefied gas storage tank of the liquefied gas carrier, at least a portion of the liquefied gas is supplied to the liquefied gas storage tank through the manifolds 20 and 20' and stored in the liquefied gas storage tank. It may be to remove the existing gas.

The bunkering vessel may supply liquefied gas to the liquefied gas storage tank of the liquefied gas carrier by using a liquefied gas transfer line. Since the gassing-up process is performed before loading, the bunkering vessel may supply liquefied gas through the liquefied gas transfer line and the manifolds 20 and 20'. At this time, the bunkering vessel withdraws liquid liquefied gas through at least one of the liquid transfer line L10 and the spray line L11, and supplies it to the liquefied gas vaporization line L15 branching from the liquid transfer line L10. . More specifically, the liquefied gas vaporization line L15 branches from the liquefied gas supply line L14, and the liquid liquefied gas supplied to the liquid phase transfer line L10 is vaporized through the liquefied gas supply line L14. It may be supplied to the line L15.

The liquefied gas vaporization line L15 may include a liquefied gas vaporizer 15 for vaporizing liquid liquefied gas. The liquefied gas vaporization line L15 has one end connected to the liquefied gas supply line L14 and the other end connected to the gaseous manifold 22 to vaporize the liquefied gas and supply it to the liquefied gas propulsion ship. The liquefied gas vaporizer 15 may vaporize the liquefied gas in the same manner as the forced vaporizer 14 described above.

After the bunkering vessel vaporizes the liquefied gas in advance in the liquefied gas vaporizer 15 provided in the bunkering vessel, the liquefied gas in the gas phase can be supplied to the liquefied gas storage tank of the liquefied gas propulsion vessel through the gaseous phase manifold 22 . The liquefied gas propulsion ship may receive gaseous liquefied gas through the gaseous manifold 22 and supply it to the liquefied gas storage tank as it is to perform a gassing-up process.

As gaseous liquefied gas is injected into the liquefied gas storage tank of the liquefied gas propulsion ship, the gas stored in the liquefied gas storage tank may be discharged. This exhaust gas may be an inert gas, and may be supplied to the bunkering vessel through the liquid manifold 21 of the bunkering vessel. The gaseous liquefied gas may have a relatively low specific gravity compared to the exhaust gas, and may be relatively light. By injecting relatively light gaseous liquefied gas into the upper end of the liquefied gas storage tank of the liquefied gas propulsion ship, it is possible to push the relatively heavy inert gas to the lower end.

The bunkering vessel may receive and process the exhaust gas discharged from the liquefied gas propulsion vessel through the gas phase transfer line L20.

Referring to FIG. 8 , the liquid phase transfer line L10 may supply the exhaust gas to at least one of the gas combustion unit (GCU) and the vent unit 13 when the concentration of the inert gas included in the exhaust gas is greater than or equal to a predetermined value. FIG. 8 may show the first stage in that most of the exhaust gas discharged from the initial gassing up, that is, the liquefied gas storage tank is an inert gas. Liquid transfer line (L10), as described above, until the concentration of liquefied gas in the gas phase inside the liquefied gas storage tank becomes 5% (v/v) of the gas combustion unit (GCU) and the vent unit 13 At least one can be supplied.

The liquid transfer line L10 may supply the exhaust gas to the gas combustion unit GCU through the liquefied gas supply line L22 for processing. For example, the liquefied gas supply line may include the HD compressor 18 to pressurize the inert gas according to the pressure required by the gas combustion unit (GCU) and then supply it to the gas combustion unit (GCU). Alternatively, the liquid transfer line L10 may supply the exhaust gas to the vent unit 13 and discharge it to the outside for treatment.

Referring to FIG. 9 , the liquid transfer line L10 may supply the exhaust gas to at least one of the gas combustion unit (GCU) and the buffer tank 40 when the concentration of the inert gas included in the exhaust gas is less than a predetermined value. . 9 can represent the second stage after the initial gasing up, that is, that most of the exhaust gas discharged from the liquefied gas storage tank by vaporizing the liquefied gas and injecting the liquefied gas is gaseous liquefied gas or boil-off gas. As described above, the liquid transfer line (L10) converts the exhaust gas to the gas combustion unit (GCU) when the liquefied gas concentration in the gas phase inside the liquefied gas storage tank exceeds 5% (v/v), and the liquefied gas concentration is approximately 90 % (v/v), it can be supplied to the buffer tank 40 . Gas phase transfer line (L20) can be processed by supplying exhaust gas to the gas combustion unit (GCU) through the liquefied gas supply line (L22) having the HD compressor (18). Alternatively, the gas phase transfer line L20 may supply the exhaust gas to the buffer tank 40 through the liquefied gas supply line L22 including the LD compressor 17 to be processed. When the exhaust gas is supplied to the buffer tank 40, the condensate component may be separated while the exhaust gas passes through the gas-liquid separator 16 in front of the LD compressor 17.

As the exhaust gas pressurized by the LD compressor 17 expands while being supplied to the buffer tank 40 , at least a portion of the exhaust gas is condensed or liquefied to form a liquid liquefied gas. The buffer tank 40 may supply liquid liquefied gas to the liquid transfer line L10 by using the pump 41, and the liquid liquefied gas is returned to the bunkering tank 10 or the liquefied gas vaporizer 15 again. It may be supplied to the gas phase manifold 22 via.

The bunkering vessel according to this embodiment uses a liquefied gas vaporizer provided in the bunkering vessel, and injects liquefied gas in the gas phase to a liquefied gas carrier that does not have a liquefied gas vaporizer to remove the inert gas inside the liquefied gas storage tank. there is. At this time, the treatment method of the exhaust gas discharged from the liquefied gas storage tank can be performed differently depending on the degree of removal of the inert gas, and in the gassing-up process of the second stage with a high content of liquefied gas, the exhaust gas is supplied to the buffer tank. The liquefied gas in the exhaust gas can be reused.

10 is a conceptual diagram illustrating a cool-down process before bunkering in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a buffer tank 40, and the like, and the same content as described in FIG. 1 is replaced with the description of the previous embodiment decide to do

The bunkering vessel according to this embodiment may lower the internal temperature of the liquefied gas storage tank by supplying a small amount of liquefied gas to the liquefied gas storage tank of the target while the bunkering vessel is connected to the target.

The cool-down process may be to remove the gas stored in the liquefied gas storage tank by supplying a small amount of cryogenic liquefied gas to the liquefied gas storage tank in a liquid phase before loading the liquefied gas into the liquefied gas storage tank of the target. . Preferably, the bunkering vessel may supply liquefied gas to the target liquefied gas storage tank after the gassing-up process, and receive relatively high-temperature gaseous liquefied gas discharged from the liquefied gas storage tank.

More specifically, the bunkering vessel may receive a relatively high temperature liquefied gas from the liquefied gas storage tank in the initial cool-down period, and may receive a relatively low temperature liquefied gas thereafter.

The liquefied gas storage tank prior to loading of the liquefied gas may be in a state in which the liquefied gas in the gas phase, which is relatively hot compared to the liquefied gas in the liquid phase, is full. The cool-down process is to reduce the amount of liquefied gas evaporated by the high-temperature gaseous liquefied gas when the liquefied gas is loaded. Additionally, if the cryogenic liquid liquefied gas is suddenly injected into the liquefied gas storage tank during loading of the liquefied gas, it may damage a barrier structure or a structure such as a pump inside the liquefied gas storage tank. The liquefied gas storage tank and other facilities can be protected by lowering the temperature inside the liquefied gas storage tank to a temperature similar to that of liquid liquefied gas through the cool-down process.

The bunkering vessel can supply liquefied gas to the target liquefied gas storage tank by using a liquefied gas transfer line. Since the cool-down process is performed before loading, the bunkering vessel can supply liquefied gas through the liquefied gas transfer line and the manifolds 20 and 20'. At this time, the bunkering vessel may draw liquid liquefied gas through at least one of the liquid transfer line L10 and the spray line L11 and supply the liquefied gas to the liquefied gas storage tank through the liquid manifold 21 .

As the liquid liquefied gas is injected into the target liquefied gas storage tank through the liquid manifold 21, the liquid liquefied gas pushes the gaseous liquefied gas inside the liquefied gas storage tank to the upper end of the liquefied gas storage tank. be able to Specifically, the liquid liquefied gas is injected into the target liquefied gas storage tank through the liquid manifold 21 , and may be sprayed through a spray provided at the upper end of the liquefied gas storage tank.

The bunkering vessel may receive the gaseous liquefied gas discharged from the liquefied gas storage tank through the gaseous phase manifold 22 . The bunkering vessel may supply and process gaseous liquefied gas supplied from the liquefied gas storage tank through the gaseous transfer line L20 to at least one of the gas combustion unit (GCU) and the buffer tank 40 . The process of supplying gaseous liquefied gas to at least one of the gas combustion unit (GCU) and the buffer tank 40 through the liquefied gas supply line L22 and the processing process in each are replaced by the above-described embodiment.

The bunkering vessel can supply liquid liquefied gas until the temperature inside the liquefied gas storage tank is lower than -130°C.

In the boil-off gas treatment process according to the present embodiment, the target may be a liquefied gas carrier or a liquefied gas propulsion ship, and the liquefied gas storage tank may be a pressure vessel, but is not limited thereto.

The bunkering vessel according to this embodiment may supply liquid liquefied gas through a spray to the upper end of the liquefied gas storage tank to adjust the temperature inside the liquefied gas storage tank to be suitable for loading. At this time, the discharged gas has a high content of liquefied gas, so that the liquefied gas in the exhaust gas can be reused by supplying it to a buffer tank.

11 is a conceptual diagram illustrating a loading process in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a buffer tank 40, and the like, and the same content as described in FIG. 1 is replaced with the description of the previous embodiment decide to do

The bunkering vessel according to this embodiment may supply liquefied gas to the liquefied gas storage tank of the target while the bunkering vessel is connected to the target. According to the above-described process, the inside of the target liquefied gas storage tank may be a suitable condition for loading cryogenic liquefied gas.

The bunkering vessel may supply liquid liquefied gas to the target liquefied gas storage tank by using the liquefied gas supply line and the manifolds 20 and 20'. Specifically, the bunkering vessel may withdraw the liquefied gas of the bunkering tank 10 through the liquid transfer line L10 and supply it to the liquefied gas storage tank through the liquid manifold 21 .

The liquefied gas storage tank of the target may be filled with relatively low-temperature gaseous liquefied gas supplied during the cool-down process. The bunkering vessel may receive the gaseous liquefied gas discharged from the liquefied gas storage tank through the gaseous phase manifold 22 . The bunkering vessel may supply and process gaseous liquefied gas supplied from the liquefied gas storage tank through the gaseous transfer line L20 to at least one of the gas combustion unit (GCU) and the buffer tank 40 . The process of supplying gaseous liquefied gas to at least one of the gas combustion unit (GCU) and the buffer tank 40 through the liquefied gas supply line L22 and the processing process in each are replaced by the above-described embodiment.

In the boil-off gas treatment process according to the present embodiment, the target may be a liquefied gas carrier or a liquefied gas propulsion ship, and the liquefied gas storage tank may be a pressure vessel, but is not limited thereto.

The unloading process in the bunkering vessel may be performed by reversing the loading process. The bunkering vessel may withdraw the liquefied gas stored in the liquefied gas storage tank through the liquid manifold 21 . In the case of performing the loading process for the liquefied gas carrier, the discharged gaseous liquefied gas may be processed by the liquefied gas carrier, but may be supplied and processed by the bunkering vessel.

The bunkering vessel according to this embodiment can reuse the liquefied gas by loading the liquid liquefied gas into the target vessel and supplying the gaseous liquefied gas discharged from the liquefied gas storage tank to the buffer tank.

12 is a conceptual diagram illustrating a gas combustion process after bunkering in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a buffer tank 40, and the like, and the same content as described in FIG. 1 is replaced with the description of the previous embodiment decide to do

The bunkering vessel may process the liquefied gas stored in the buffer tank 40 during the bunkering process for the target. Specifically, the liquefied gas may be evaporated inside the buffer tank 40 to form boil-off gas.

The bunkering vessel according to the present embodiment may further include a power generation engine (G/E) for generating electric power by using liquefied gas as a fuel.

BOG generated inside the buffer tank 40 may be withdrawn through the buffer tank withdrawal line L41 and supplied to the liquefied gas supply line L22. One end of the buffer tank withdrawal line L41 may be connected to the upper end of the buffer tank 40 , and the other end may be connected to the front end of the gas-liquid separator 16 in the liquefied gas supply line L22 .

The liquefied gas supplied to the gas-liquid separator 16 may be separated into a gaseous phase and a liquid phase, and the gaseous liquefied gas is pressurized in the LD compressor 17 through the liquefied gas supply line L22 and supplied to the power generation engine G/E. can be supplied. The liquid phase may be returned to the bunkering tank 10 through the condensate return line L23 as a condensate.

The gas combustion process as described above has been described as being performed after bunkering in a bunkering vessel, but is not limited thereto. When liquefied gas exists in the buffer tank 40 of the bunkering vessel, the gas combustion process according to the present embodiment may be performed in parallel in other processes below.

13 and 14 are conceptual views illustrating a warming-up process of a target liquefied gas storage tank in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a buffer tank 40, and the like, and the same content as described in FIG. 1 is replaced with the description of the previous embodiment decide to do

After the bunkering vessel according to this embodiment unloads liquefied gas from the liquefied gas storage tank of the target, the bunkering vessel supplies the liquefied gas to the liquefied gas storage tank in a state connected to the target, and discharges from the liquefied gas storage tank exhaust gas can be supplied.

During the liquefied gas unloading process, sloshing may occur in the liquefied gas storage tank in which the liquid liquefied gas fluctuates by the flow of the liquefied gas according to the withdrawal of the liquefied gas, and in this process, at least a portion of the liquefied gas may evaporate. In addition, as the liquefied gas is withdrawn, the liquefied gas remaining in the liquefied gas storage tank is further evaporated to form boil-off gas. After the liquefied gas is loaded, the liquefied gas storage tank may be filled with boil-off gas, that is, liquefied gas of a gaseous phase in a low temperature state. In the warm-up process, in order to empty the inside of the liquefied gas storage tank, relatively high temperature liquefied gas may be supplied to the liquefied gas storage tank through the manifolds 20 and 20' to increase the temperature inside the liquefied gas storage tank.

The bunkering vessel may use at least one of the heater 19 and the liquefied gas vaporizer 15 provided on the liquefied gas supply line L22 to vaporize the liquefied gas and supply it to the liquefied gas storage tank. The bunkering vessel stores liquefied gas by additionally heating the boil-off gas supplied through the gas phase transfer line L20 in the heater 19 or vaporizing the liquefied gas supplied through the liquid phase transfer line L10 in the liquefied gas vaporizer 15. Can be supplied by tank.

In the warming-up process, gaseous liquefied gas may be supplied to the target's liquefied gas storage tank through the liquid phase transfer line (L10) or the gaseous phase transfer line (L20) according to the temperature inside the target's liquefied gas storage tank. The bunkering vessel may supply gaseous liquefied gas through the liquidus manifold 21 or the gaseous manifold 22 in consideration of the temperature inside the liquefied gas storage tank.

Referring to FIG. 13 , immediately after unloading the liquefied gas from the liquefied gas storage tank, the bunkering vessel may supply the liquefied gas to the target liquefied gas storage tank through the liquid phase transfer line L10. Immediately after unloading, since the low-temperature liquefied gas inside the liquefied gas storage tank is full, the relatively high-temperature gaseous liquefied gas is supplied to the upper end of the liquefied gas storage tank through the liquid manifold 21 to generate low-temperature liquefied gas. It can be pushed to the bottom of the liquefied gas storage tank. The exhaust gas discharged from the liquefied gas storage tank may be supplied to the gas phase transfer line L20 through the gas phase manifold 22 .

The gas phase transfer line L20 may receive liquefied gas, which is an exhaust gas discharged from the liquefied gas storage tank, and deliver it to the liquefied gas supply line L22. Liquefied gas is supplied to the buffer tank 40 through the gas-liquid separator 16 and the LD compressor 17 provided on the liquefied gas supply line L22, or is supplied to the heater 19 through the HD compressor 18. After being heated again, it may be injected back into the liquefied gas storage tank through the liquid manifold 21 .

Referring to FIG. 14 , the bunkering vessel injects gaseous liquefied gas into the liquefied gas storage tank and, when the internal temperature of the liquefied gas storage tank becomes higher than a predetermined value, the gaseous liquefied gas is transferred to the liquefied gas through the gaseous transfer line L20. It can be supplied to a storage tank. As the liquefied gas in the relatively high temperature gas phase is stored in the liquefied gas storage tank, the liquefied gas in the gas phase is supplied to the lower end of the liquefied gas through the gas phase manifold 22 and the remaining low temperature liquefied gas is pushed to the upper part of the liquefied gas. can pay The exhaust gas discharged from the liquefied gas storage tank may be supplied to the liquid transfer line L10 through the liquid manifold 21 .

The liquid transfer line L10 may receive liquefied gas, which is an exhaust gas discharged from the liquefied gas storage tank, and deliver it to the liquefied gas supply line L22. After the liquefied gas is supplied to the heater 19 through the HD compressor 18 provided on the liquefied gas supply line and heated again, it may be injected back into the liquefied gas storage tank through the gaseous gas manifold 22 . At this time, it may be used after receiving the liquefied gas from the bunkering tank 10 and supplying it to the heater 19 through the HD compressor 18 together.

The bunkering vessel can supply liquefied gas until the temperature inside the liquefied gas is higher than -10℃.

In the warm-up process according to the present embodiment, the target may be a liquefied gas carrier or a liquefied gas propulsion ship, and the liquefied gas storage tank may be a pressure vessel, but is not limited thereto.

The bunkering vessel according to the present embodiment can protect the liquefied gas storage tank and the equipment provided therein even when the temperature inside the liquefied gas storage tank is increased after unloading and then inert gas is injected. At this time, by heating the liquefied gas discharged from the liquefied gas storage tank again and injecting it into the liquefied gas, the warm-up process can be performed by maximally utilizing the flow rate of the liquefied gas in the liquefied gas storage tank.

15 is a conceptual diagram illustrating a gas freeing process of a target liquefied gas storage tank in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a gas supply unit 30, a buffer tank 40, etc. It will be replaced with the contents of the previous embodiment.

The gas freeing process is similar to the inerting process in terms of supplying an inert gas to the liquefied gas storage tank. However, the gas freeing process is performed after unloading the liquefied gas from the liquefied gas storage tank of the target and increasing the internal temperature of the liquefied gas storage tank through a warm-up process. The gas freeing process may be to remove the liquefied gas inside the liquefied gas storage tank by supplying the inert gas to the liquefied gas storage tank through the manifolds 20 and 20' after the warm-up process.

The liquefied gas storage tank that has undergone the warm-up process may be filled with relatively high-temperature gaseous liquefied gas. Through the gas freeing process, the liquefied gas in the liquefied gas storage tank can be withdrawn, recovered, used or treated, and the explosive gas in the liquefied gas storage tank can be removed by supplying an inert gas into the liquefied gas storage tank. Hereinafter, the explosive gas may be a liquefied gas.

The gas supply unit 30 may be an inert gas supply unit, and the inert gas may be nitrogen gas or a gas generated by burning heavy oil. The inert gas supply unit may be at least one of an inert gas generating device generating nitrogen gas and a combustion device capable of burning heavy oil. The inert gas may be the same as that used in the inerting process described above. That is, the inert gas may have an oxygen concentration of 5% (v/v) or less, preferably an oxygen concentration of 2% (v/v) or less, and most preferably an oxygen concentration of 1% (v/v) or less. v) may be the following.

The inert gas supply unit may produce an inert gas and supply the inert gas to the liquefied gas storage tank through the gas supply line L30. The gas supply line L30 may supply an inert gas to the manifolds 20 and 20' through the liquid phase transfer line L10. The inert gas may be supplied to the lower end of the liquefied gas storage tank through the liquid manifold 21 . The inert gas may be relatively heavier than the liquefied gas, and is supplied to the lower end of the liquefied gas storage tank to push the liquefied gas in the liquefied gas storage tank to the upper end of the liquefied gas storage tank.

The bunkering vessel can receive and treat the exhaust gas discharged by injecting inert gas into the liquefied gas storage tank. The exhaust gas may be a gaseous liquefied gas, and may be supplied to the gaseous transfer line L20 through the gaseous manifold 22 .

The bunkering vessel can process the liquefied gas supplied from the liquefied gas storage tank by supplying it to at least one of the gas combustion unit (GCU), the vent unit 13 and the buffer tank 40 . Liquefied gas may be supplied to at least one of the gas combustion unit (GCU) and the buffer tank 40 through the liquefied gas supply line (L22) through the vapor transfer line (L20), and a vent unit through the vapor transfer line (L20) (13) can be supplied. For example, in the initial stage of the gas freeing process, liquefied gas may be included in the exhaust gas supplied from the target liquefied gas storage tank at approximately 90% (v/v), and in this case, the liquefied gas is the LD compressor (17). It may be supplied to the buffer tank 40 through When the liquefied gas content in the exhaust gas decreases, it may be supplied to the gas combustion unit (GCU) through the HD compressor 18 . Finally, when most of the exhaust gas is an inert gas such as nitrogen gas, it may be supplied to the vent unit 13 to be discharged.

The inert gas supply unit may supply the inert gas until the liquefied gas concentration in the liquefied gas storage tank is lower than 2% (v/v). When the concentration of liquefied gas in the liquefied gas storage tank is lower than 2% (v/v), the risk of explosion in the liquefied gas storage tank is significantly lowered.

In the boil-off gas treatment process according to the present embodiment, the target may be a liquefied gas carrier or a liquefied gas propulsion ship, and the liquefied gas storage tank may be a pressure vessel, but is not limited thereto. In the case of performing the gas freeing process for the liquefied gas carrier, the exhaust gas may be treated by the liquefied gas carrier, but may be supplied and processed by the bunkering vessel.

The bunkering vessel according to this embodiment may remove the liquefied gas inside the liquefied gas storage tank of the target by using the inert gas generated inside the bunkering vessel, and the liquefied gas may be recovered and processed or reused by the bunkering vessel.

16 and 17 are conceptual views illustrating an aerating process of a liquefied gas storage tank of a target in a bunkering vessel according to an embodiment of the present invention. The bunkering vessel may include a bunkering tank 10, a manifold 20, a liquefied gas transfer line, a gas supply unit 30, a buffer tank 40, etc. It will be replaced with the contents of the previous embodiment.

The aerating process is similar to the drying process in terms of supplying dry gas to the liquefied gas storage tank. However, the aerating process is performed after unloading the liquefied gas from the liquefied gas storage tank of the target, and filling the liquefied gas storage tank with an inert gas through gas freeing. The aerating process may be to remove the inert gas inside the liquefied gas storage tank by supplying dry gas to the liquefied gas storage tank through the manifolds 20 and 20' after the gas freeing process.

The liquefied gas storage tank after the gas freeing process may be filled with an inert gas. The liquefied gas storage tank may be maintained in a state full of inert gas, and then may be performed sequentially from the gassing-up process to load the liquefied gas again. The aerating process may be performed when a person needs to enter the inside of the liquefied gas storage tank for maintenance and repair of the inside of the liquefied gas storage tank, that is, to create an environment in which a person can breathe. Therefore, aerating may be a process of adjusting the oxygen concentration inside the liquefied gas storage tank to about 20% (v/v).

The gas supply unit 30 may be a dry gas supply unit, and the dry gas may be air containing oxygen and may be dry air not containing moisture. The dry gas supply unit may be to produce dry gas by using electric power produced by the power generation engine (G/E) of the bunkering vessel.

The dry gas supply unit may produce dry gas and supply the dry gas to the liquefied gas storage tank through the gas supply line L30. The gas supply line L30 may supply dry gas to the manifolds 20 and 20' through at least one of the liquid phase transfer line L10 and the gaseous phase transfer line L20.

At this time, the gas supply line (L30) is used in the gas freeing process and depending on the type of inert gas filling the inside of the liquefied gas storage tank, the dry gas can be supplied through the liquid transfer line (L10) or the gaseous transfer line (L20). there is.

Referring to FIG. 16 , the gas supply line L30 may supply dry gas through the gas phase transfer line L20 when the inert gas generated by burning heavy oil in the liquefied gas storage tank is filled. The gas supply line L30 may supply dry gas to the upper end of the liquefied gas storage tank through the gas phase manifold 22 through the gas phase transfer line L20. Dry gas may have a lighter weight than the inert gas formed by combustion, and is supplied to the upper end of the liquefied gas storage tank and descends to the lower end of the liquefied gas storage tank to remove the inert gas in the liquefied gas storage tank from the lower end of the liquefied gas storage tank. can be pushed to

Referring to FIG. 17 , the gas supply line L30 may supply dry gas through the liquid transfer line L10 when the inert gas, which is nitrogen gas, is filled in the liquefied gas storage tank. The gas supply line L30 may supply dry gas to the lower end of the liquefied gas storage tank through the liquid manifold 21 through the liquid phase transfer line L10. Dry gas may have a heavier weight than nitrogen gas of relatively low temperature, and it is possible to push the inert gas to the top of the liquefied gas storage tank.

Regardless of the drying gas supply method, the drying gas supply unit may supply the drying gas until the oxygen concentration in the liquefied gas storage tank becomes 20% (v/v) or more.

Most of the exhaust gas emitted when dry gas is injected into the liquefied gas storage tank is an inert gas, and the content of the liquefied gas is very low or hardly contained, so it is okay to dispose of it as it is in the target.

In the aerating process according to this embodiment, the target may be a liquefied gas carrier or a liquefied gas propulsion ship, and the liquefied gas storage tank may be a pressure vessel, but is not limited thereto.

When the bunkering vessel according to this embodiment requires maintenance and repair inside the liquefied gas storage tank after unloading of the liquefied gas storage tank, it provides an environment in which a person can work inside the liquefied gas storage tank by supplying dry gas. can

It goes without saying that the present invention is not limited to the embodiments described above, and a combination of the embodiments or a combination of at least one of the embodiments and a known technology may be included as another embodiment.

In the above, the present invention has been described focusing on the embodiments of the present invention, but this is merely an example and does not limit the present invention. It will be appreciated that various combinations or modifications and applications not illustrated in the embodiments are possible within the scope. Accordingly, descriptions related to modifications and applications that can be easily derived from the embodiments of the present invention should be interpreted as being included in the present invention.

10: bunkering tank 11: first pump
12: second pump 13: vent unit
14: forced vaporizer 15: liquefied gas vaporizer
16: gas-liquid separator 17: LD compressor
18: HD Compressor 19: Heater
20, 20': Manifold 21: Liquid Manifold
22: gaseous manifold 30: gas supply
40: buffer tank 41: pump
L10: liquid transfer line L11: spray line
L12: Liquefied gas return line L13: Spray return line
L14: Liquefied gas supply line L15: Liquefied gas vaporization line
L20: gas phase transfer line L21: vent line
L22: Liquefied gas supply line L23: Condensate return line
L30: gas supply line L40: buffer tank supply line
L41: buffer tank withdrawal line

Claims (9)

As a bunkering vessel for loading and unloading liquefied gas to the liquefied gas storage tank of the target,
bunkering tanks for storing liquefied gas;
a manifold provided at the bunkering station of the bunkering vessel to flow in and out of the liquefied gas from the bunkering vessel;
a liquefied gas transfer line connecting the bunkering tank and the manifold to flow the liquefied gas;
and a liquefied gas supply line branching from the liquefied gas transfer line and supplying liquefied gas from the bunkering tank to the gas combustion unit,
The gas combustion unit,
Burning and processing the boil-off gas generated in the bunkering tank,
The liquefied gas supply line is
and a compressor for supplying liquefied gas by pressurizing it to the pressure required by the gas combustion unit,
The bunkering vessel,
Bunkering vessel, characterized in that it further comprises a buffer tank for storing at least a portion of the pressurized liquefied gas. The method of claim 1,
The liquefied gas transfer line is
a liquid transfer line for transferring liquid liquefied gas; and
Bunkering vessel, characterized in that it comprises a gaseous transfer line for transferring the gaseous liquefied gas. 3. The method of claim 2,
The gas phase transfer line is
Bunkering vessel, characterized in that receiving the boil-off gas generated in the liquefied gas storage tank. 4. The method of claim 3,
The gas phase transfer line is
Bunkering vessel, characterized in that for transferring at least a portion of the supplied boil-off gas to the liquefied gas supply line. The method of claim 1,
The liquefied gas supply line is
A bunkering vessel comprising a gas-liquid separator for separating liquefied gas into gaseous and liquid phases and returning the liquid liquefied gas to the bunkering tank. delete delete The method of claim 1,
The bunkering station is
It is provided on the upper deck of the bunkering vessel,
The manifold is
Bunkering vessel, characterized in that it is disposed on at least one of the stern and one side of the bunkering vessel. The method of claim 1,
The subject is
A bunkering vessel, characterized in that it is a liquefied gas propulsion ship propelled by liquefied gas as fuel.

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