Bunkering ship

Abstract

The bunkering ship of the present invention is for loading and unloading liquefied gas into a target liquefied gas storage tank, and includes a bunkering tank for storing liquefied gas, a manifold installed at a bunkering station of the bunkering ship for inputting and outputting liquefied gas from the bunkering ship, a liquefied gas transfer line connecting the bunkering tank and the manifold to flow the liquefied gas, and a dry gas supply unit for producing dry gas, wherein the dry gas supply unit supplies dry gas to the liquefied gas storage tank through the manifold to remove moisture inside the liquefied gas storage tank before loading liquefied gas into the liquefied gas storage tank.

Description

[Technical Field]

[0001] The present invention relates to a bunkering vessel. [Background technology]

[0002] In recent years, with the strengthening of environmental regulations, the use of liquefied natural gas (LNG), which is considered one of the most environmentally friendly fuels, has been increasing. LNG is generally transported via LNG carriers, where it can be stored in the tanks of LNG carriers in a liquid state by lowering its temperature to below -162°C at 1 atmosphere. When LNG is in a liquid state, its volume is reduced to 1 / 600 of that of its gaseous state, which increases transportation efficiency.

[0003] Unlike diesel, liquefied natural gas must be maintained at cryogenic temperatures when being loaded or unloaded onto a ship that transports or uses it as fuel. Furthermore, to ensure stable storage of the liquefied natural gas while loading or unloading, the temperature and pressure of the storage tank in which the liquefied natural gas is stored must be controlled. Therefore, in recent years, continuous research and development has been conducted on bunkering technologies for maintaining liquefied natural gas in a liquid state and supplying it to a liquefied natural gas carrier or propulsion vessel, and on ships that use the same. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been created to solve the problems of the prior art as described above, and an object of the present invention is to provide a bunkering ship capable of loading and unloading liquefied gas into a target liquefied gas storage tank.

[0005] Another object of the present invention is to provide a bunkering ship capable of controlling the temperature and pressure conditions inside a target liquefied gas storage tank so as to meet the requirements of individual processes for loading and unloading liquefied gas. [Means for solving the problem]

[0006] A bunkering vessel according to one aspect of the present invention is a bunkering vessel for loading and unloading liquefied gas into a target liquefied gas storage tank, and includes: a bunkering tank for storing liquefied gas; a manifold installed at a bunkering station of the bunkering vessel for inflow and outflow of liquefied gas from the bunkering vessel; a liquefied gas transfer line connecting the bunkering tank and the manifold for flowing the liquefied gas; and a dry gas supply unit for producing dry gas, wherein the dry gas supply unit supplies dry gas to the liquefied gas storage tank via the manifold before loading the liquefied gas into the liquefied gas storage tank. and removes moisture from inside the liquefied gas storage tank, the liquefied gas transfer line includes a liquid phase transfer line that transfers the liquid phase liquefied gas and a gas phase transfer line that transfers the gas phase liquefied gas, the bunkering vessel further includes a gas supply line that transfers the dry gas supplied from the dry gas supply unit to at least one of the liquid phase transfer line and the gas phase transfer line, and the gas supply line can supply the dry gas through the liquid phase transfer line when the external temperature of the bunkering vessel is equal to or higher than a predetermined temperature, and can supply the dry gas through the gas phase transfer line when the external temperature of the bunkering vessel is lower than the predetermined temperature.

[0007] A bunkering vessel according to another aspect of the present invention is a bunkering vessel for loading and unloading liquefied gas into a target liquefied gas storage tank, and includes: a bunkering tank for storing liquefied gas; a manifold installed at a bunkering station of the bunkering vessel for inflow and outflow of liquefied gas from the bunkering vessel; a liquefied gas transfer line connecting the bunkering tank and the manifold for flowing the liquefied gas; and a dry gas supply unit for producing dry gas, wherein the dry gas supply unit supplies dry gas to the liquefied gas storage tank via the manifold before loading the liquefied gas into the liquefied gas storage tank. the liquefied gas storage tank is heated to a temperature above a predetermined temperature, and the bunkering vessel further includes a gas supply line that transmits dry gas supplied from the dry gas supply unit to at least one of the liquid phase transfer line and the gas phase transfer line, and the gas supply line can supply dry gas through the liquid phase transfer line when the internal temperature of the liquefied gas storage tank is equal to or higher than a predetermined temperature, and can supply dry gas through the gas phase transfer line when the internal temperature of the liquefied gas storage tank is lower than the predetermined temperature.

[0008] A bunkering vessel according to another aspect of the present invention is a bunkering vessel for loading and unloading liquefied gas into a target liquefied gas storage tank, and includes: a bunkering tank for storing liquefied gas; a manifold installed at a bunkering station of the bunkering vessel for inputting and outputting liquefied gas from the bunkering vessel; a liquefied gas transfer line connecting the bunkering tank and the manifold for flowing the liquefied gas; and an inert gas supply unit for producing inert gas, wherein the inert gas supply unit supplies inert gas to the liquefied gas storage tank via the manifold before loading the liquefied gas into the liquefied gas storage tank, thereby producing the liquefied gas. Oxygen is removed from inside the storage tank, and the liquefied gas transfer line includes a liquid phase transfer line that transfers the liquefied gas in liquid phase and a gas phase transfer line that transfers the liquefied gas in gas phase, and the bunkering vessel further includes a gas supply line that transmits the inert gas supplied from the inert gas supply unit to at least one of the liquid phase transfer line and the gas phase transfer line, and the inert gas is nitrogen gas or a gas generated by burning heavy oil, and the gas supply line can supply the inert gas via the liquid phase transfer line if the inert gas is nitrogen gas, or via the gas phase transfer line if the inert gas is a gas generated by burning heavy oil.

[0009] A bunkering vessel according to another aspect of the present invention is a bunkering vessel for loading and unloading liquefied gas into and from a liquefied gas carrier equipped with a liquefied gas vaporizer, the bunkering vessel comprising: a bunkering tank for storing liquefied gas; a manifold provided at a bunkering station of the bunkering vessel for allowing liquefied gas to flow in and out of the bunkering vessel; and a liquefied gas transfer line connecting the bunkering tank and the manifold for allowing the liquefied gas to flow. Before loading liquefied gas into the liquefied gas carrier, the bunkering vessel supplies liquefied gas at a flow rate relatively smaller than the flow rate of liquefied gas during loading to a liquefied gas storage tank provided in the liquefied gas carrier through the manifold, and receives a supply of exhaust gas from the liquefied gas carrier. The liquefied gas transfer line is a liquid-phase bunkering vessel for transferring liquefied gas in a liquid phase. The bunkering vessel includes a transfer line and a gas phase transfer line for transporting gas phase liquefied gas, wherein the bunkering vessel supplies liquefied gas to the liquefied gas vaporizer via the liquid phase transfer line, and the exhaust gas is the gas stored in the liquefied gas storage tank that is discharged as the liquefied gas vaporized in the liquefied gas vaporizer is injected into the liquefied gas storage tank, and the bunkering vessel receives the exhaust gas via the gas phase transfer line, and the gas phase transfer line supplies the exhaust gas to at least one of a gas combustion unit and a vent section when the concentration of an inert gas contained in the exhaust gas is equal to or greater than a predetermined value, and supplies the exhaust gas to at least one of a gas combustion unit and a buffer tank when the concentration of the inert gas contained in the exhaust gas is less than a predetermined value.

[0010] A bunkering vessel according to another aspect of the present invention is a bunkering vessel 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 installed at a bunkering station of the bunkering vessel for inflow and outflow of liquefied gas from the bunkering vessel; a liquefied gas transfer line connecting the bunkering tank and the manifold for flowing the liquefied gas; and a liquefied gas vaporizer. Before loading the liquefied gas into the liquefied gas storage tank, the bunkering vessel supplies liquefied gas vaporized in the liquefied gas vaporizer to the liquefied gas storage tank through the manifold, and receives a supply of exhaust gas from the target, and the liquefied gas transfer line includes a liquid phase transfer line for transferring the liquid phase liquefied gas and a gas phase transfer line for transferring the gas phase liquefied gas. and a transfer line, wherein the liquefied gas vaporizer receives liquefied gas from the bunkering tank, vaporizes it, and then supplies it to the vapor phase transfer line, and the exhaust gas is the gas stored in the liquefied gas storage tank that is discharged as the liquefied gas vaporized by the liquefied gas vaporizer is injected into the liquefied gas storage tank, and the bunkering ship receives the exhaust gas through the liquid phase transfer line, and the liquid phase transfer line supplies the exhaust gas to at least one of a gas combustion unit and a vent section when the concentration of the inert gas contained in the exhaust gas is equal to or greater than a predetermined value, and supplies the exhaust gas to at least one of a gas combustion unit and a buffer tank when the concentration of the inert gas contained in the exhaust gas is less than a predetermined value.

[0011] A bunkering vessel according to another aspect of the present invention is a bunkering vessel for loading and unloading liquefied gas into a liquefied gas storage tank of a target, the bunkering vessel comprising: a bunkering tank for storing liquefied gas; a manifold provided at a bunkering station of the bunkering vessel for inflow and outflow of liquefied gas from the bunkering vessel; and a liquefied gas transfer line connecting the bunkering tank and the manifold for flowing the liquefied gas. After unloading the liquefied gas from the liquefied gas storage tank, the bunkering vessel supplies the liquefied gas to the liquefied gas storage tank through the manifold, and receives a supply of exhaust gas from the target, the exhaust gas being liquefied gas remaining in the liquefied gas storage tank, and the bunkering vessel transfers the liquefied gas supplied from the bunkering tank. and a liquefied gas vaporizer for vaporizing the liquefied gas being discharged. After unloading the liquefied gas from the liquefied gas storage tank, the bunkering vessel supplies the gaseous liquefied gas to the liquefied gas storage tank. The liquefied gas transfer line includes a liquid phase transfer line for transferring the liquid liquefied gas and a gas phase transfer line for transferring the gaseous liquefied gas. Immediately after unloading the liquefied gas from the liquefied gas storage tank, the bunkering vessel supplies the liquefied gas to the liquefied gas storage tank via the liquid phase transfer line and receives exhaust gas via the gas phase transfer line. When the temperature inside the liquefied gas storage tank becomes higher than a predetermined value, the bunkering vessel supplies the liquefied gas to the liquefied gas storage tank via the gas phase transfer line and receives exhaust gas via the liquid phase transfer line.

[0012] A bunkering vessel according to another aspect of the present invention is a bunkering vessel 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 installed at a bunkering station of the bunkering vessel for feeding and discharging liquefied gas from the bunkering vessel; and a liquefied gas transfer line connecting the bunkering tank and the manifold for flowing the liquefied gas. After unloading the liquefied gas from the liquefied gas storage tank, the bunkering vessel supplies the liquefied gas to the liquefied gas storage tank through the manifold, and supplies exhaust gas from the target. the exhaust gas is liquefied gas remaining in the liquefied gas storage tank, the bunkering vessel further includes a liquefied gas vaporizer that vaporizes the liquefied gas supplied from the bunkering tank, and after unloading the liquefied gas from the liquefied gas storage tank, supplies the gaseous liquefied gas to the liquefied gas storage tank, the liquefied gas transfer line includes a liquid phase transfer line that transfers the liquid phase liquefied gas and a gas phase transfer line that transfers the gas phase liquefied gas, the liquefied gas transfer line supplies the exhaust gas to a buffer tank, and the buffer tank supplies the liquid phase liquefied gas to the bunkering tank.

[0013] A bunkering vessel according to another aspect of the present invention is a bunkering vessel for loading and unloading liquefied gas into a target liquefied gas storage tank, and includes: a bunkering tank for storing liquefied gas; a manifold installed at a bunkering station of the bunkering vessel for inflow and outflow of liquefied gas from the bunkering vessel; a liquefied gas transfer line connecting the bunkering tank and the manifold for flowing the liquefied gas; and an inert gas supply unit for producing inert gas, wherein the inert gas supply unit unloads the liquefied gas from the liquefied gas storage tank and then transfers the inert gas through the manifold. the bunkering vessel supplies inert gas to the liquefied gas storage tank via a gas phase transfer line and receives a supply of exhaust gas from the target, the liquefied gas transfer line including a liquid phase transfer line for transferring the liquid liquefied gas and a gas phase transfer line for transferring the gas phase liquefied gas, the bunkering vessel supplies inert gas to the liquefied gas storage tank via the liquid phase transfer line and receives a supply of exhaust gas via the gas phase transfer line, the gas phase transfer line supplies the exhaust gas to at least one of a gas combustion unit, a vent section, and a buffer tank, the exhaust gas includes liquefied gas, and the buffer tank can supply the liquid phase liquefied gas to the bunkering tank.

[0014] A bunkering vessel according to another aspect of the present invention is a bunkering vessel for loading and unloading liquefied gas into a target liquefied gas storage tank, and includes: a bunkering tank for storing liquefied gas; a manifold installed at a bunkering station of the bunkering vessel for inflow and outflow of liquefied gas from the bunkering vessel; a liquefied gas transfer line connecting the bunkering tank and the manifold for flowing the liquefied gas; and a dry gas supply unit for producing dry gas, wherein the dry gas supply unit unloads the liquefied gas from the liquefied gas storage tank and then transfers the dry gas to the bunkering vessel through the manifold. The inert gas is supplied to the liquefied gas storage tank and discharged from the liquefied gas storage tank, the liquefied gas transfer line including a liquid phase transfer line for transferring the liquid phase liquefied gas and a gas phase transfer line for transferring the gas phase liquefied gas, the bunkering vessel further including a gas supply line for transmitting the dry gas supplied from the dry gas supply unit to at least one of the liquid phase transfer line and the gas phase transfer line, and when the inert gas is nitrogen gas, the dry gas can be supplied via the liquid phase transfer line, and when the inert gas is gas generated by burning heavy oil, the dry gas can be supplied via the gas phase transfer line.

[0015] A bunkering vessel according to another aspect of the present invention is a bunkering vessel for loading and unloading liquefied gas into a target liquefied gas storage tank, and includes: a bunkering tank for storing liquefied gas; a manifold installed at a bunkering station of the bunkering vessel for allowing liquefied gas to flow in and out of the bunkering vessel; a liquefied gas transfer line connecting the bunkering tank and the manifold for allowing the liquefied gas to flow; a power generation engine for producing electricity using the liquefied gas as fuel; and a liquefied gas supply line branching off from the liquefied gas transfer line for supplying liquefied gas from the bunkering tank to the power generation engine; The line supplies evaporated gas generated in the bunkering tank to the power generation engine, and the liquefied gas transfer line includes a liquid phase transfer line that transfers liquid phase liquefied gas and a gas phase transfer line that transfers gas phase liquefied gas, the liquid phase transfer line supplies liquid phase liquefied gas to the liquefied gas storage tank via the manifold, and the gas phase transfer line receives a supply of evaporated gas generated in the liquefied gas storage tank, the bunkering vessel further includes a second liquefied gas supply line branching from the liquid phase transfer line and supplying liquid phase liquefied gas to the liquefied gas supply line, and the second liquefied gas supply line may be equipped with a forced vaporizer that vaporizes the liquid phase liquefied gas.

[0016] A bunkering vessel according to another aspect of the present invention is a bunkering vessel for loading and unloading liquefied gas into a target liquefied gas storage tank, and includes: a bunkering tank for storing the liquefied gas; a manifold installed at a bunkering station of the bunkering vessel for allowing the liquefied gas to flow in and out of the bunkering vessel; a liquefied gas transfer line connecting the bunkering tank and the manifold for allowing the liquefied gas to flow; a power generation engine for producing electricity using the liquefied gas as fuel; and a liquefied gas supply line branching off from the liquefied gas transfer line for supplying the liquefied gas from the bunkering tank to the power generation engine. The liquefied gas supply line supplies evaporated gas generated in the bunkering tank to the power generation engine, and the liquefied gas supply line includes a gas-liquid separator that separates the liquefied gas into a gas phase and a liquid phase and returns the liquid phase liquefied gas to the bunkering tank, and an LD compressor that receives the gas phase liquefied gas from the gas-liquid separator and pressurizes it to a pressure required by the power generation engine, and further includes a buffer tank that stores exhaust gas supplied from the target in the process of loading the liquefied gas into the target, and the exhaust gas is gas stored in the liquefied gas storage tank and is discharged, and may include liquefied gas.

[0017] A bunkering vessel according to another aspect of the present invention is a bunkering vessel for loading and unloading liquefied gas into a target liquefied gas storage tank, and includes: a bunkering tank for storing liquefied gas; a manifold installed at a bunkering station of the bunkering vessel for inputting and outputting liquefied gas from the bunkering vessel; a liquefied gas transfer line connecting the bunkering tank and the manifold for flowing the liquefied gas; and a liquefied gas supply line branching from the liquefied gas transfer line for supplying liquefied gas from the bunkering tank to a gas combustion unit, wherein the gas combustion unit burns and treats evaporated gas generated in the bunkering tank, the liquefied gas supply line has a compressor that pressurizes the liquefied gas to a pressure required by the gas combustion unit and supplies it, and the bunkering vessel may further include a buffer tank for storing at least a portion of the pressurized liquefied gas. [Effects of the Invention]

[0018] The bunkering vessel according to the present invention can load and unload cryogenic liquefied gas into a target liquefied gas storage tank, and can control the conditions such as temperature and pressure inside the liquefied gas storage tank to the conditions required for each individual process for loading and unloading.

[0019] In addition, the bunkering vessel according to the present invention can minimize undesirable vaporization of liquefied gas during the loading and unloading process of the liquefied gas.

[0020] In addition, the bunkering vessel according to the present invention can treat exhaust gases generated during the loading and unloading process of the target liquefied gas storage tank.

[0021] In addition, the bunkering vessel according to the present invention can automatically process the evaporated gas generated inside the bunkering tank. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a conceptual diagram of a bunkering system for a bunkering vessel according to an embodiment of the present invention. [Figure 2] FIG. 2 is a conceptual diagram showing a gas treatment process before bunkering in a bunkering vessel according to an embodiment of the present invention. [Figure 3] FIG. 2 is a conceptual diagram showing the process of treating evaporated gas generated in a target liquefied gas storage tank before bunkering in a bunkering vessel according to one embodiment of the present invention. [Figure 4] FIG. 2 is a conceptual diagram showing a drying process for supplying dry gas or an inert gas for supplying inert gas in a bunkering vessel according to an embodiment of the present invention. [Figure 5] FIG. 2 is a conceptual diagram showing a drying process for supplying dry gas or an inert gas for supplying inert gas in a bunkering vessel according to an embodiment of the present invention. [Figure 6] 1 is a conceptual diagram showing a primary gassing-up process for supplying liquefied gas to a liquefied gas carrier in a bunkering ship according to an embodiment of the present invention. [Figure 7] 1 is a conceptual diagram showing 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. FIG. [Figure 8] 1 is a conceptual diagram showing a primary gassing-up process for supplying liquefied gas to a liquefied gas propelled ship in a bunkering ship according to an embodiment of the present invention. [Figure 9] 1 is a conceptual diagram showing a secondary gassing-up process for supplying liquefied gas to a liquefied gas propelled ship in a bunkering ship according to an embodiment of the present invention. FIG. [Figure 10] FIG. 2 is a conceptual diagram showing a cool-down process for supplying liquefied gas in a bunkering vessel according to an embodiment of the present invention. [Figure 11] 1 is a conceptual diagram showing 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. FIG. [Figure 12] FIG. 2 is a conceptual diagram showing a gas treatment process after bunkering in a bunkering vessel according to an embodiment of the present invention. [Figure 13] 1 is a conceptual diagram showing a first warm-up process for supplying high-temperature liquefied gas to a target liquefied gas storage tank in a bunkering vessel according to an embodiment of the present invention. [Figure 14] FIG. 1 is a conceptual diagram showing a secondary warming-up process for supplying high-temperature liquefied gas to a target liquefied gas storage tank in a bunkering vessel according to an embodiment of the present invention. [Figure 15] 1 is a conceptual diagram showing 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. [Figure 16] 1 is a conceptual diagram showing an aeration process for supplying dry gas in a bunkering vessel according to an embodiment of the present invention. FIG. [Figure 17] 1 is a conceptual diagram showing an aeration process for supplying dry gas in a bunkering vessel according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] The objectives, particular 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 this specification, when referring to components in each drawing, it should be noted that the same components are assigned the same numbers as much as possible, even if they appear in different drawings. Furthermore, when describing the present invention, if it is determined that a detailed description of related prior art may unnecessarily obscure the gist of the present invention, such a detailed description will be omitted.

[0024] In the following, it should be noted that high pressure (HP), low pressure (LP), high temperature and low temperature are relative and do not indicate absolute values, and can be used relatively in each embodiment of the present invention.

[0025] In the following, a bunkering vessel means a vessel that can load and unload liquefied gas into a target liquefied gas storage tank and can use the stored liquefied gas as fuel.

[0026] It should be noted that, hereinafter, the term "subject" is used to encompass all offshore plants such as FSRUs and FPSOs, as well as liquefied gas carriers that carry liquefied gas as cargo and liquefied gas-propelled ships that can use liquefied gas as fuel. The term "subject" may also encompass 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 one or more of the above.

[0027] In the following, when the object is a liquefied gas carrier, the bunkering vessel according to the present invention may be provided to perform the following process for the trial operation of the liquefied gas carrier.

[0028] Hereinafter, the term "liquefied gas" may be used to encompass all gas fuels that are generally stored in a liquid state at low temperatures, such as LNG, LPG, ethylene, ammonia, etc. However, in the following examples and drawings, the liquefied gas will be described as liquefied natural gas.

[0029] Hereinafter, boil-off gas (BOG) may refer to liquefied gas that has been naturally vaporized or forcibly vaporized. However, boil-off gas may be used to mean not only gaseous boil-off gas but also liquefied boil-off gas. Furthermore, liquefied gas may be used as a term that encompasses both liquid state and gaseous state that has been naturally vaporized or forcibly vaporized.

[0030] Hereinafter, bunkering refers to both loading, which is the act of supplying liquefied gas from a bunkering vessel to a target, and unloading, which is the act of removing liquefied gas from a target and supplying it to the bunkering vessel.

[0031] Hereinafter, when the bunkering vessel is connected to the target, it means that the manifold and piping are connected so that liquefied gas, evaporated gas, or other gas can be communicated between the bunkering vessel and the target.

[0032] In the following, expressions such as "first," "second," etc. are intended to indicate that a specific configuration is provided in multiple numbers in the present invention, and each expression can refer to any one of the multiple configurations.

[0033] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0034] FIG. 1 is a conceptual diagram showing a bunkering system, which is an internal system of a bunkering vessel according to an embodiment of the present invention.

[0035] 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, etc. Although not shown below, each line may be equipped with a valve for controlling the flow rate of the fluid flowing through the corresponding line.

[0036] The bunkering tank 10 may be a storage tank that is installed inside the bunkering vessel and stores 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 installed inside the bunkering vessel. For example, the bunkering tanks 10 may be installed side by side along the bow to stern of the vessel, or side by side on the port and starboard sides of the vessel.

[0037] The bunkering tank 10 is connected to a manifold 20, which will be described later, and can supply liquefied gas stored therein to a target or receive liquefied gas from the target via the manifold 20. Specifically, a liquefied gas transfer line is provided, one end of which is connected to the bunkering tank 10 and the other end of which is connected to the manifold 20, so that the liquefied gas can flow. The liquefied gas transfer line may include a liquid phase transfer line L10, a gas phase transfer line L20, and a spray line L11.

[0038] Hereinafter, the liquid phase transfer line L10 and the gas phase transfer line L20 refer to lines for communicating liquid and gas phase liquefied gas, respectively, based on the loading process in which liquefied gas is supplied from the bunkering vessel to the target liquefied gas storage tank. The spray line L11 may refer to a line for communicating liquid phase liquefied gas, and may have a lower flow rate of liquefied gas than the liquid phase transfer line L10. Hereinafter, the liquid phase transfer line L10 may refer to both the liquid phase transfer line L10 and the spray line L11, or may refer to at least one of the liquid phase transfer line L10 and the spray line L11. However, these transfer lines are not necessarily intended to communicate only liquid or gas phase liquefied gas, and as described below, liquefied gas in other states, or dry gas or inert gas may also be communicated instead of liquefied gas.

[0039] The bunkering tank 10 may be provided with a first pump 11 and a second pump 12. Although not shown, the first pump 11 may be provided in the lower part of a pump tower and may be installed so as to be immersed in the liquefied gas. The first pump 11 may be installed so as to be spaced apart from the bottom inside the bunkering tank 10. The liquefied gas extracted by the first pump 11 may be supplied to the manifold 20 (described below) via a liquefied gas transfer line. Specifically, the liquefied gas extracted by the first pump 11 may be supplied to the manifold 20 via a liquid phase transfer line L10. The liquid phase transfer line L10 may be provided with a return line (not shown) that can return the extracted liquefied gas to the bunkering tank 10.

[0040] The second pump 12 is installed inside the bunkering tank 10 and can be located 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 can be used for loading and unloading liquefied gas. The second pump 12 is for additionally pumping a small amount of liquefied gas remaining inside the bunkering tank 10 after the loading and unloading processes and can pump liquefied gas located at a height that the first pump 11 cannot process. In addition, the second pump 12 can be used to transfer liquefied gas from the bunkering tank 10 when the bunkering vessel supports the gassing-up process or the cool-down process of the vessel.

[0041] For example, the second pump 12 may be disposed inside a sump (not shown) formed at the bottom inside the bunkering tank 10. The sump may be provided in the form of a pool of water at the bottom of the bunkering tank 10, and may be provided so that a small amount of liquefied gas accumulates in the sump after most of the liquefied gas is removed from the bunkering tank 10. The second pump 12 may remove the liquefied gas that has accumulated in the sump.

[0042] The liquefied gas extracted by the second pump 12 can be supplied to the manifold 20 via a spray line L11. The spray line L11 is connected to the liquid phase transfer line L10 and can transfer the extracted liquefied gas to the liquid phase transfer line L10. The spray line L11 can be provided with a liquefied gas return line L12 connected to a return line branching from the liquid phase transfer line L10. The flow rate of the liquefied gas flowing through the liquefied gas return line L12 can be adjusted to adjust the flow rate of the liquefied gas supplied to the liquid phase transfer line L10 via the spray line L11. The spray line L11 can be provided with a spray return line L13. The spray return line L13 returns at least a portion of the liquefied gas flowing through the spray line L11 to the inside of the bunkering tank 10 and is provided at an upper level inside the bunkering tank 10, so that the liquefied gas can be sprayed and returned. The spray return line L13 can inject at least a portion of the liquefied gas into the evaporated gas generated inside the bunkering tank 10 to lower the temperature inside the bunkering tank 10.

[0043] A gas phase transfer line L20 and a vent line L21 may be installed in the upper part of the bunkering tank 10. The evaporated gas of the liquefied gas generated inside the bunkering tank 10 may be supplied to the manifold 20 via the gas phase transfer line L20. In addition, the evaporated gas of the liquefied gas generated inside the bunkering tank 10 may be supplied to a vent section 13 (described later) via the vent line L21. The gas phase transfer line L20 may supply a portion of the extracted evaporated gas to the vent section 13. The vent section 13 may be supplied with liquefied gas or a dry gas or an inert gas (described later) and discharge it outside the bunkering vessel. When the pressure inside the bunkering tank 10 reaches or exceeds a predetermined level, the bunkering vessel may supply at least a portion of the evaporated gas to the vent section 13 via the gas phase transfer line L20 for discharge.

[0044] The manifold 20 is installed in the bunkering station of the bunkering vessel and is connected to a liquefied gas transfer line to allow liquefied gas to be input or output from the bunkering vessel. The bunkering station provides a location for connection to loading and unloading targets via piping (not shown). The liquefied gas transfer line may be connected to the manifold 20. The manifold 20 may include a liquid phase manifold 21 connected at one end to the liquid phase transfer line L10 and a gas phase manifold 22 connected at one end to the gas phase transfer line L20. That is, one end of the spray line L11 may also be connected to the liquid phase manifold 21. The other end of each manifold may be connected to the target via a separately installed piping. The piping is installed in the loading arm (not shown) and is suitable for transferring cryogenic liquefied gas. It may be connected to the manifold 20 using a cryogenic adapter, a cryogenic coupler, or the like.

[0045] Although not shown, the bunkering station may be provided with an ESD (Emergency Shut-Down system) connected to the manifold 20, and may be provided with sensors for monitoring the temperature, pressure, flow rate, etc. of the liquefied gas communicated through the manifold 20, and a valve for controlling the flow rate of the liquefied gas. The bunkering station may be provided on the upper level of the bunkering tank 10 in the bunkering vessel. For example, the bunkering station may be located above or below the upper deck, and the bunkering tank 10 may be located between the bottom of the bunkering vessel and the bunkering station.

[0046] The manifold 20 may be provided with a plurality of liquid phase manifolds 21 and a plurality of gas phase manifolds 22. 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 phase manifolds 21 and one gas phase manifold 22, or one gas phase manifold 22 may be disposed between two liquid phase manifolds 21.

[0047] A plurality of manifolds 20 may be provided on the bunkering vessel. For example, the bunkering vessel may include one manifold 20 on its port or starboard side and another manifold 20' at its stern. The manifold 20 may be provided on one side of the bunkering vessel and connected to a liquefied gas carrier, a propulsion vessel, a platform, etc., and the other manifold 20' located at the stern may provide a structure suitable for connection to another bunkering vessel. Each manifold may have the same configuration as each other, but is not limited to this. When the bunkering vessel has a plurality of manifolds 20, 20', the liquid phase transfer line L10 may be connected to the liquid phase transfer line 21 of each manifold 20, 20', and the gas phase transfer line L20 may be connected to the gas phase transfer line 22 of each manifold 20, 20'. It should be understood that the spray line L11 may also be connected to the liquid phase transfer line 21 of each manifold 20, 20'. That is, one end of the liquefied gas transfer line is connected to the bunkering tank 10, and the other end is branched and connected to each of the manifolds 20, 20'.

[0048] As described above, the liquefied gas transfer line may include a liquid phase transfer line L10 and a gas phase transfer line L20 based on the loading process in which liquefied gas is supplied from the bunkering vessel to the target, and may further include a spray line L11. The spray line L11 may have one end connected to the liquid phase transfer line L10 to transfer the liquid phase liquefied gas, or may be directly connected to the manifolds 20, 20' to transfer the liquefied gas. In this case, the spray line L11 may transfer the liquefied gas at a lower flow rate than the liquid phase transfer line L10.

[0049] The liquefied gas transfer line may be connected to liquefied gas supply lines L14 and L22. Specifically, the liquefied gas supply line L22 may branch off from the gas-phase transfer line L20 and supply gas-phase liquefied gas to at least one of a gas combustion unit (GCU), a power generation engine (G / E), and a buffer tank 40 (described later). The gas combustion unit GCU may combust and treat the liquefied gas, then discharge it outside the bunkering vessel for treatment. The power generation engine G / E may generate electricity using the liquefied gas as fuel. Preferably, the power generation engine G / E may use the gas-phase liquefied gas as fuel. The buffer tank 40 may temporarily store the liquefied gas and then supply it to a location where it is needed, and may temporarily store the gas-phase liquefied gas. The buffer tank 40 may separate the supplied liquefied gas into liquid and gas phases and extract them.

[0050] The liquefied gas supply line L14 branches off from at least one of the liquid-phase transfer line L10 and the spray line L11, and can vaporize the liquid-phase liquefied gas before transmitting it to the liquefied gas supply line L22. The liquefied gas supply line L14 is equipped with a forced vaporizer 14, and can vaporize the liquid-phase liquefied gas before transmitting it to the liquefied gas supply line L22.

[0051] The liquefied gas supply line L22 receives gas-phase liquefied gas from the liquefied gas transfer line and then branches it again to supply it to at least one of the gas combustion unit GCU, the power generation engine G / E, and the buffer tank 40. Specifically, the gas combustion unit GCU, the power generation engine G / E, and the buffer tank 40 may each require different gas temperature and pressure conditions. A plurality of liquefied gas supply lines L22 may be provided in parallel, and one of the liquefied gas supply lines L22 may be equipped with an LD (low-duty) compressor 17, and another of the liquefied gas supply lines L22 may be equipped with an HD (high-duty) compressor 18. The liquefied gas supply line L22 may supply the liquefied gas to the destination via one of the compressors depending on the type of destination and its corresponding requirements.

[0052] 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 gas phase and a liquid phase, and supplies only the gas-phase liquefied gas to at least one of the gas combustion unit GCU, the power generation engine G / E, and the buffer tank 40 via the liquefied gas supply line L22. The liquid phase separated by the gas-liquid separator 16 is a condensate formed by condensing at least a portion of the gas-phase liquefied gas, and may be returned to the bunkering tank 10 via a condensate return line L23. Preferably, the gas-liquid separator 16 may be provided upstream of the LD compressor 17.

[0053] The liquefied gas supply line L22 may further include a heater 19. The heater 19 may further heat the liquefied gas supplied through 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 as it is pressurized by the compressors 17 and 18, but may be lower than the temperature required by the aforementioned destination. The heater 19 may further heat the liquefied gas to match the temperature level required by the destination. Preferably, the heater 19 may be provided after the HD compressor 18.

[0054] For example, referring to the drawings, the liquefied gas supply line L22 may branch off from the gas-phase transfer line L20 and then branch off into a plurality of liquefied gas supply lines L22. Any one of the liquefied gas supply lines L22 may be provided with a gas-liquid separator 16 and an LD compressor 17, which may transfer gas-phase liquefied gas and supply it to at least one of the gas combustion unit GCU, the power generation engine G / E, and the buffer tank 40. In this case, the liquefied gas supply line L14 may merge with the gas-liquid separator 16 upstream to receive gas-phase liquefied gas and supply it to the gas-liquid separator 16. The other liquefied gas supply line L22 may be provided with an HD compressor 18 and a heater 19, which may transfer heated gas-phase liquefied gas and supply it to at least one of the gas combustion unit GCU and the power generation engine G / E.

[0055] 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 via the manifold 20. In the gas supply unit 30, the gas may be at least one of a dry gas and an inert gas, and the gas supply unit 30 may produce and supply at least one of the dry gas and the inert gas to the target.

[0056] The gas supply line L30 has one end connected to the gas supply unit 30 and the other end connected to a liquefied gas transfer line, thereby communicating gas. The gas supply line L30 is connected to at least one of the liquid phase transfer line L10, the gas phase transfer line L20, and the spray line L11, thereby transmitting gas supplied from the gas supply unit 30. Preferably, the gas supply line L30 is connected to at least one of the liquid phase transfer line L10 and the gas phase transfer line L20. The gas produced in the gas supply unit 30 can be transmitted to the manifold 20 via the gas supply line L30 and the liquefied gas transfer line, and can be supplied to the target liquefied gas storage tank via the manifold 20.

[0057] The bunkering vessel may include a buffer tank 40. The buffer tank 40 is provided separately from the bunkering tank 10 and may be used in the loading and unloading process using the bunkering vessel. The buffer tank 40 is provided in the form of a pressure vessel and may store contents at a relatively high pressure compared to the bunkering tank 10.

[0058] The buffer tank 40 may be provided with a pump 41. The pump 41 may be installed inside the buffer tank 40 and installed to extract liquefied gas. The liquefied gas extracted by the pump 41 may be supplied to a liquefied gas transfer line. For example, the liquid-phase liquefied gas extracted from the buffer tank 40 may be supplied to at least one of the bunkering tank 10 and the manifold 20 via the liquid-phase transfer line L10. At this time, at least a portion of the extracted liquefied gas may be returned to the buffer tank 40 in a spray manner, similar to the spray return line L13.

[0059] In addition, the buffer tank 40 may be provided with a buffer tank supply line L40. One end of the buffer tank supply line L40 is connected to the liquefied gas supply line L22, and the other end is connected to the inside of the buffer tank 40, so that the liquefied gas supplied from the liquefied gas supply line L22 can be delivered to the buffer tank 40. The buffer tank supply line L40 may be installed to supply the liquefied gas to a lower part of the buffer tank 40. When liquid-phase liquefied gas exists inside the buffer tank 40, the liquefied gas delivered through the buffer tank supply line L40 is supplied into the liquid-phase liquefied gas and may be condensed or liquefied by the cold heat of the liquid-phase liquefied gas.

[0060] The buffer tank 40 may also be provided with a buffer tank discharge line L41. One end of the buffer tank discharge line L41 is provided at the upper end of the buffer tank 40, allowing the liquefied gas inside the buffer tank 40 to be discharged. The other end of the buffer tank discharge line L41 may be connected to the vapor phase transfer line L20. In this case, the evaporated gas generated inside the buffer tank 40 is discharged through the buffer tank discharge line L41 and can flow through the vapor phase transfer line L20. Alternatively, the buffer tank discharge line L41 may be provided with the other end connected to the liquefied gas supply line L22. The evaporated gas generated inside the buffer tank 40 is discharged through the buffer tank discharge line L41 and can be supplied to at least one of the gas combustion unit GCU, the power generation engine G / E, and the buffer tank 40 via the liquefied gas supply line L22.

[0061] Although not shown, an agitator may be installed 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 may occur between the upper and lower sections inside the buffer tank 40 over time. The agitator ensures uniform mixing of the fluid inside the buffer tank 40, thereby preventing a decrease in the efficiency of condensation or liquefaction inside the buffer tank 40.

[0062] Although not shown, the bunkering vessel may be equipped with at least one of a liquefied gas reliquefaction system and an auxiliary boiler instead of the buffer tank 40. Alternatively, the bunkering vessel may be equipped with at least one of a buffer tank 40, a reliquefaction system, and an auxiliary boiler. The reliquefaction system can receive and liquefy the gas phase liquefied gas generated during the bunkering process, and then supply the bunkering tank 10. The auxiliary boiler can receive and burn the gas phase liquefied gas generated during the bunkering process to generate steam, and the generated steam can be supplied to steam demands on the bunkering vessel.

[0063] 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, etc., and can perform loading and unloading processes for the target liquefied gas.

[0064] Hereinafter, the loading and unloading process 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 into a target using a bunkering vessel will be described.

[0065] The bunkering vessel can store liquefied gas in the bunkering tank 10 for loading into the target liquefied gas storage tank. The bunkering vessel can also initially receive a supply of liquefied gas from a land or offshore platform, another bunkering vessel, etc.

[0066] The bunkering vessel can operate with liquefied gas stored in the bunkering tank 10 and can drive other equipment on board. That is, the bunkering vessel can use liquefied gas as fuel even before bunkering to drive a power generation engine G / E, etc. In addition, the liquefied gas can evaporate inside the bunkering tank 10, generating evaporated gas, which may require treatment to manage the pressure resistance of the bunkering tank 10. Therefore, the bunkering vessel can use liquefied gas as fuel even before bunkering. Preferably, the bunkering vessel can use liquefied gas in the gas phase as fuel. This gas treatment process is a gas firing process.

[0067] The gas combustion process may include extracting evaporated gas generated in the bunkering tank 10 and supplying it to the power generation engine G / E, etc. At this time, the evaporated gas generated in the bunkering tank 10 may vary depending on the environment in which the bunkering vessel is located and whether the bunkering vessel is operating or not. If the flow rate of evaporated gas generated in the bunkering tank 10 is less than the flow rate of liquefied gas required by the power generation engine G / E, etc., further liquid-phase liquefied gas can be extracted from the bunkering tank 10 and supplied. The gas combustion process can be performed not only before bunkering but also in all other processes where liquefied gas exists inside the bunkering tank 10. Specific details of the gas combustion process will be described later with reference to FIG. 2.

[0068] The bunkering vessel can be connected to a target to perform the bunkering process, and can receive and treat evaporative gas from the target before loading or unloading. The bunkering vessel can receive evaporative gas generated in the target's liquefied gas storage tank via the manifold 20 and supply it to at least one of the gas combustion unit GCU and the buffer tank 40 for treatment. This treatment process is a BOG treatment process. The BOG treatment process will be described in detail below with reference to FIG. 3.

[0069] The bunkering vessel can supply at least one of dry gas and inert gas (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 can supply 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 required for loading. The process of supplying dry gas is called drying, and the process of supplying inert gas is called inerting.

[0070] The drying process is a process of removing moisture from the liquefied gas storage tank by injecting dry gas, which is air that does not contain moisture, into the tank. The drying process can be broadly divided into two types depending on the temperature conditions under which the process is carried out. For example, the drying process can be divided into a process carried out under relatively low temperature conditions such as winter and a process carried out under relatively high temperature conditions such as summer.

[0071] The inerting process can be performed after the drying process and involves injecting an inert gas into a liquefied gas storage tank to remove the dry gas that has filled the liquefied gas storage tank. Inerting processes can be broadly divided into two types depending on the type of inert gas used. Hereinafter, inert gas refers to both inert gas generated by burning heavy oil and nitrogen gas. For example, inerting processes can be divided into those that use gas generated by burning heavy oil and those that use nitrogen gas. Specific details about the drying and inerting processes will be described below with reference to FIGS. 4 and 5.

[0072] The bunkering ship can supply a relatively small amount of liquefied gas to the liquefied gas storage tank before loading the liquefied gas into the target liquefied gas storage tank. The bunkering ship can extract a portion of the liquid-phase liquefied gas stored in the bunkering tank 10 and supply it to the liquefied gas storage tank. This liquefied gas supply process is called gassing-up.

[0073] The gassing process can be divided into multiple stages depending on the environmental conditions inside the liquefied gas storage tank. Furthermore, depending on the conditions of the object receiving the liquefied gas, the gassing process can be divided into a process of supplying the liquefied gas in a liquid phase or a process of supplying the liquefied gas after vaporizing it on the bunkering vessel. The gassing process can be performed after drying or inerting, and involves injecting liquefied gas into the liquefied gas storage tank and removing the dry gas and inert gas stored inside the liquefied gas storage tank. The gassing process will be described in detail below with reference to FIGS. 6 to 9.

[0074] Before loading the liquefied gas into the target liquefied gas storage tank, the bunkering vessel can supply a relatively small amount of liquefied gas to the liquefied gas storage tank. This liquefied gas supply process is called cooling down.

[0075] The cool-down process can prevent the formation of evaporative gas or reduce the amount of evaporative gas generated when loading liquefied gas by lowering the temperature inside the liquefied gas storage tank. The cool-down process can be performed after gassing-up, and can lower the temperature inside the liquefied gas storage tank by injecting low-temperature liquefied gas into the liquefied gas storage tank. Specific details of the cool-down process will be described later with reference to FIG. 10.

[0076] After the cool-down process, the bunkering vessel can load liquefied gas into the target liquefied gas storage tank. The bunkering vessel can supply liquid-phase liquefied gas to the target liquefied gas storage tank and at the same time receive a supply of low-temperature liquefied gas that has been filled inside the liquefied gas storage tank. Specific details of the loading process will be described later with reference to FIG. 11.

[0077] The bunkering vessel can further process gases generated during the loading, unloading, and cooling down processes. The gases can be evaporated gases, and similar to the gas combustion process described above, they can be supplied to a power generation engine G / E, etc., and burned for processing. This gas processing process is also a gas combustion process. Specific details of the gas combustion process after bunkering will be described later with reference to FIG. 12.

[0078] The bunkering vessel can unload liquefied gas from the target liquefied gas storage tank in the reverse way of loading. After unloading, the bunkering vessel can supply liquefied gas to the liquefied gas storage tank to raise the temperature inside the liquefied gas storage tank. This liquefied gas supply process is called warming up.

[0079] The warming-up process can inject relatively high-temperature liquefied gas into a liquefied gas storage tank to discharge liquefied gas remaining in the liquefied gas storage tank. The warming-up process can be performed after unloading, and can supply vaporized liquefied gas to a target liquefied gas storage tank to vaporize and discharge the liquefied gas remaining in the liquefied gas storage tank that has not been unloaded. The discharged exhaust gas can be supplied to the bunkering vessel and treated therein. In addition, the warming-up process can be divided into a process in which the bunkering vessel is supplied with relatively low-temperature liquefied gas and a process in which the bunkering vessel is supplied with relatively high-temperature liquefied gas, depending on the conditions of the exhaust gas supplied from the target liquefied gas storage tank. Specific details of the warming-up process will be described later with reference to FIGS. 13 and 14.

[0080] 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 called gas freeing.

[0081] The gas freeing process involves injecting inert gas into a target liquefied gas storage tank to discharge the liquefied gas from the liquefied gas storage tank. The discharged gas can then be supplied to the bunkering ship for treatment. The gas freeing process will be described in detail below with reference to FIG. 15.

[0082] The bunkering vessel can supply dry gas to the target liquefied gas storage tank after gas freeing. The process of supplying dry gas after gas freeing is called aerating.

[0083] The aerating process involves injecting dry gas into a target liquefied gas storage tank to remove inert gas from the liquefied gas storage tank. Specific details of the aerating process will be described later with reference to Figures 16 and 17.

[0084] Hereinafter, the individual processes 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 Figures 2 to 17. Figures 2 to 17 illustrate the case where the liquefied gas is liquefied natural gas, and it will be understood that the liquefied gas is not limited to a specific type.

[0085] 2 is a conceptual diagram showing the gas combustion process before bunkering in a bunkering vessel according to one 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, etc., and the same content as that described with reference to FIG. 1 shall be substituted for that described in the previous embodiment.

[0086] The bunkering vessel according to this embodiment may further include a power generation engine G / E that generates electricity using liquefied gas as fuel. The bunkering vessel can generate electricity by supplying the liquefied gas extracted through the liquefied gas transfer line to the power generation engine G / E through liquefied gas supply lines L14 and L22 and combusting the liquefied gas.

[0087] Before bunkering, i.e., before loading liquefied gas into the target, the bunkering vessel can receive a supply of liquefied gas for loading from an external source and store it in the bunkering tank 10. The bunkering vessel can receive a supply of liquefied gas from an external source via a manifold 20. The bunkering vessel can receive a supply of liquid-phase liquefied gas via a liquid-phase manifold 21 and simultaneously return gas-phase liquefied gas via a gas-phase manifold 22. The liquid-phase manifold 21 can supply the liquid-phase liquefied gas to the bunkering tank 10 via at least one of the liquid-phase transfer line L10 and the spray line L11, and the gas-phase manifold 22 can supply the gas-phase liquefied gas to the bunkering tank 10 via the gas-phase transfer line L20.

[0088] The liquefied gas stored in the bunkering tank 10 can be taken out again via at least one of the liquid phase transfer line L10, the spray line L11, and the vapor phase transfer line L20. Although not shown, the bunkering vessel can take out the liquid phase liquefied gas stored in the bunkering tank 10 via at least one of the liquid phase transfer line L10 and the spray line L11 and transfer it to the liquefied gas supply line L14, and take out the evaporated gas of the liquefied gas generated inside the bunkering tank 10 via the vapor phase transfer line L20 and transfer it to the liquefied gas supply line L22.

[0089] The bunkering vessel can preferentially extract the evaporated gas generated inside the bunkering tank 10 and supply it to the liquefied gas supply line L22. This allows the pressure inside the bunkering tank 10 to be maintained constant or within a safe range. The power generation engine G / E can produce electricity to be used by the bunkering vessel. The flow rate of the evaporated gas generated inside the bunkering tank 10 may vary depending on the temperature where the bunkering vessel is located, the sailing speed of the bunkering vessel, and the temperature and pressure conditions inside the bunkering tank 10. The flow rate of the evaporated gas 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 can additionally extract a portion of the liquid-phase liquefied gas stored in the bunkering tank 10 and supply it via the liquefied gas supply line L14 to meet the demand of the power generation engine G / E.

[0090] For example, the bunkering vessel can extract evaporated gas through the vapor phase transfer line L20 and supply it to the power generation engine G / E through a liquefied gas supply line L22 branching off from the vapor phase transfer line L20. The bunkering vessel can also extract liquid phase liquefied gas through at least one of the liquid phase transfer line L10 and the spray line L11 and supply it to the power generation engine G / E through a liquefied gas supply line L14 branching off from the liquid phase transfer line L10 or the spray line L11. More specifically, a forced vaporizer 14 can be provided on the liquefied gas supply line L14, which can vaporize the liquid phase liquefied gas and supply the vaporized liquefied gas to the liquefied gas supply line L22.

[0091] The forced vaporizer 14 can vaporize the liquefied gas by utilizing a heat source present inside the bunkering vessel. The heat source can be seawater, fresh water used inside the bunkering vessel, steam, engine exhaust gas generated inside the bunkering vessel, etc., but the type is not limited and any heat source can be used as long as it can vaporize the cryogenic liquefied gas.

[0092] The forcedly vaporized liquefied gas and the evaporated gas may be combined in the liquefied gas supply line L22 and supplied to the gas-liquid separator 16 installed on the liquefied gas supply line L22. The gas-liquid separator 16 may temporarily store the supplied liquefied gas and may be installed in the form of a mist separator or a buffer tank. The gas-liquid separator 16 may separate the supplied liquefied gas into a gas phase and a liquid phase and supply only the gas phase liquefied gas via the liquefied gas supply line L22. For example, when the liquefied gas is liquefied natural gas, the liquefied gas may further contain relatively heavy carbons such as ethane and propane in addition to methane. The gas-liquid separator 16 may condense the heavy carbons contained in the liquefied gas and a portion of the liquefied gas to form condensate, and the formed condensate may be transferred to the bunkering tank 10 via the condensate return line L23.

[0093] The gas-phase liquefied gas supplied from the gas-liquid separator 16 can be pressurized by the LD compressor 17 to the pressure required by the power generation engine G / E and supplied. The liquefied gas pressurized by the LD compressor 17 can be heated to the temperature required by the power generation engine G / E, but may also be in a relatively high temperature state compared to the required temperature. For example, if the liquefied gas is liquefied natural gas, the liquefied gas flowing in the upstream of the LD compressor 17 may be natural gas in a relatively low temperature state as evaporated gas, and the liquefied gas in the downstream of the LD compressor 17 may be natural gas in a relatively high temperature state.

[0094] Although not shown, a plurality of LD compressors 17 can be provided in series or in parallel. The LD compressor 17 may be provided with a cooler in its downstream stage for cooling the pressurized liquefied gas. The cooler can cool the liquefied gas to a temperature required by the power generation engine G / E and supply it to the power generation engine G / E. A recirculation line (not shown) for one or more LD compressors 17 can 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 adjust the pressure and flow rate of the liquefied gas discharged from the downstream stage of the LD compressor 17 to meet the requirements of the power generation engine G / E.

[0095] The above-described gas combustion process has been described as an example performed before bunkering in a bunkering vessel, but is not limited to this. If liquefied gas exists inside the bunkering tank 10 of the bunkering vessel, the gas combustion process according to this embodiment can be performed in parallel with the following other processes. That is, although the gas combustion process according to this embodiment is not illustrated in Figures 3 to 17, it will be understood that the gas combustion process can be performed simultaneously with the processes performed in each of the corresponding figures.

[0096] 3 is a conceptual diagram showing the evaporation gas treatment process before bunkering in a bunkering vessel according to one 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, etc., and the same content as that described with reference to FIG. 1 shall be substituted for that described in the previous embodiment.

[0097] The bunkering vessel according to this embodiment can receive and process evaporated gas generated in the target liquefied gas storage tank while the bunkering vessel is connected to the target. Preferably, the bunkering vessel can receive and process evaporated gas generated in the target liquefied gas storage tank before unloading. For example, if the liquefied gas is liquefied natural gas, the bunkering vessel can receive a supply of natural gas in a relatively low temperature state as evaporated gas of the liquefied natural gas via the gas phase manifold 22.

[0098] The bunkering vessel can receive a supply of evaporated gas through the gas phase manifold 22 of the manifolds 20, 20'. The bunkering vessel can transfer the evaporated gas supplied through the gas phase manifold 22 to the liquefied gas supply line L22 via the gas phase transfer line L20.

[0099] 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 be equipped with a gas-liquid separator 16 and an LD compressor 17, and another liquefied gas supply line may be equipped with an HD compressor 18 and a heater 19. The bunkering vessel can treat the evaporated gas supplied via the gas phase manifold 22 by supplying it to each of the plurality of liquefied gas supply lines L22.

[0100] In this embodiment, the bunkering vessel may utilize at least one of a gas combustion unit GCU and a buffer tank 40 to process the supplied evaporative gas.

[0101] For example, the evaporated gas is transmitted to a liquefied gas supply line L22 equipped with an HD compressor 18 and a heater 19, and the liquefied gas supply line L22 can receive the evaporated gas and supply it to the gas combustion unit GCU. The evaporated gas 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 can combust the evaporated gas and discharge it to the outside for treatment.

[0102] For example, the evaporated gas is transferred via the gas phase transfer line L20 to the liquefied gas supply line L22 equipped with the gas-liquid separator 16 and the LD compressor 17, and the liquefied gas supply line L22 receives the evaporated gas and supplies it to the buffer tank 40. The separation of the gas phase liquefied gas and condensate through the gas-liquid separator 16 is substituted for the above-mentioned embodiment. The gas phase liquefied gas separated in the gas-liquid separator 16 passes through the LD compressor 17, becomes a relatively high temperature state, and can be supplied to the buffer tank 40.

[0103] The buffer tank 40 can temporarily store at least a portion of the pressurized liquefied gas. The buffer tank 40 can receive a supply of gaseous liquefied gas via a buffer tank supply line L40. The gaseous liquefied gas expands as it flows into the relatively bulky buffer tank 40, and at least a portion of it can be liquefied. Alternatively, the gaseous liquefied gas can be cooled by low-temperature liquefied gas previously stored in the buffer tank 40, and at least a portion of it can be condensed or liquefied. The buffer tank 40 can supply the liquid-phase liquefied gas to the bunkering tank 10 using a pump 41.

[0104] In the evaporation gas treatment 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, but is not limited to, a pressure vessel. In addition, the vapor phase transfer line L20 may receive and treat evaporation gas supplied through the vapor phase manifold 22, as well as evaporation gas generated inside the bunkering tank 10 of the bunkering ship, and may also receive and treat the same method.

[0105] Although the above-described evaporation gas treatment process has been described as being performed before unloading on the bunkering vessel, it is not limited to this. The bunkering vessel according to this embodiment can treat evaporation gas generated in the target liquefied gas storage tank using the gas combustion unit GCU and buffer tank 40 installed on the bunkering vessel, thereby simplifying the equipment for treating evaporation gas on the target and adjusting the pressure inside the target liquefied gas storage tank before bunkering, thereby enabling the bunkering process to be carried out smoothly and safely.

[0106] 4 and 5 are conceptual diagrams showing 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, etc., and the same content as that described with reference to FIG. 1 shall be substituted for the content of the previous embodiment.

[0107] The bunkering vessel according to this embodiment can supply at least one of dry gas and inert gas to the liquefied gas storage tank of the target when the bunkering vessel is connected to the target.

[0108] First, an example of a drying process for supplying dry gas will be described. The drying process may involve supplying dry gas to a target liquefied gas storage tank via manifolds 20 and 20′ to remove moisture from the liquefied gas storage tank before loading the liquefied gas into the target liquefied gas storage tank.

[0109] Before loading liquefied gas, the liquefied gas storage tank may be filled with air. The air may have an oxygen concentration of approximately 20% (v / v) and a composition similar to that of ordinary air, including a trace amount of water vapor. The amount of water contained in the air is extremely small compared to oxygen and nitrogen, and may take the form of small droplets or water vapor. However, when loading cryogenic liquefied gas, this may solidify inside the liquefied gas storage tank, potentially damaging components such as the liquefied gas storage tank or the pump installed inside the liquefied gas storage tank. The drying process can remove moisture from the liquefied gas storage tank to protect the liquefied gas storage tank and other equipment.

[0110] 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 produce dry gas using electricity generated by a power generation engine G / E of the bunkering vessel.

[0111] The dry gas supply unit produces dry gas and supplies it to the target liquefied gas storage tank via the gas supply line L30. Since the drying process is performed before loading, the dry gas supply unit can supply the dry gas via the liquefied gas transfer line and the manifolds 20 and 20'. The gas supply line L30 can supply the dry gas to the manifolds 20 and 20' via at least one of the liquid phase transfer line L10, the gas phase transfer line L20, and the spray line L11.

[0112] In this case, the gas supply line L30 can supply dry gas through the liquid phase transfer line L10 or the vapor phase transfer line L20 depending on the external temperature of the bunkering vessel or the internal temperature of the target liquefied gas storage tank. Alternatively, the gas supply line L30 can supply dry gas through the liquid phase transfer line L10 or the vapor phase transfer line L20 depending on the specific gravity difference between the gas supplied to the bunkering vessel and the internal gas of the bunkering vessel. At the bunkering station, the manifolds 20, 20' can be connected to the target liquefied gas storage tank through piping including insulation, but this is affected by the external temperature of the bunkering vessel. Therefore, even if insulation is provided in the piping, the gas moving through the piping can be heated by receiving heat from the external environment.

[0113] The bunkering vessel can supply dry gas through a liquid phase manifold 21 or a gas phase manifold 22, taking into consideration such temperature and specific gravity conditions. It should be noted that each manifold is named based on the liquefied gas loading and unloading process. The liquid phase manifold 21 can be connected, with or without piping, to not only the liquid phase transfer line L10 installed in the bunkering vessel, but also to a liquid phase transfer line (not shown) connected to the target liquefied gas storage tank. The liquid phase transfer line in the target can have one end installed in the lower part of the liquefied gas storage tank, similar to the liquid phase transfer line L10 installed in the bunkering vessel. The gas phase manifold 22 can be connected, with or without piping, to not only the gas phase transfer line L20 installed in the bunkering vessel, but also to a gas phase transfer line (not shown) connected to the target liquefied gas storage tank. The gas phase transfer line in the target can also have one end installed in the upper level of the liquefied gas storage tank, similar to the gas phase transfer line L20 installed in the bunkering vessel.

[0114] Referring to FIG. 4 as one embodiment of the present invention, the gas supply line L30 may supply dry gas via the liquid phase transfer line L10 when the external temperature of the bunkering vessel is equal to or higher than a predetermined temperature. The predetermined temperature may be an external temperature that makes the temperature inside the target liquefied gas storage tank higher than the temperature of the dry gas injected into the liquefied gas storage tank via the manifolds 20 and 20′. Here, the predetermined temperature may be approximately 20 to 40°C, but is not limited thereto, and may vary depending on the season and 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 via the liquid phase transfer line L10. The gas supply line L30 may supply dry gas to the lower level of the liquefied gas storage tank via the liquid phase transfer line L10 and the liquid phase manifold 21. Dry gas having a temperature relatively lower than the temperature inside the liquefied gas storage tank can be heavier than the air inside the liquefied gas storage tank and can be supplied to the lower part of the liquefied gas storage tank to push the air inside the target liquefied gas storage tank to the upper part of the liquefied gas storage tank. Similarly, the gas supply line L30 can supply dry gas through the liquid phase transfer line L10 when the internal temperature of the target liquefied gas storage tank is higher than a predetermined temperature.

[0115] Referring to FIG. 5, when the external temperature of the bunkering vessel is lower than a predetermined temperature, the gas supply line L30 can supply dry gas via the gas phase transfer line L20. For example, in winter, the temperature inside the target liquefied gas storage tank can be relatively low, and the bunkering vessel can supply dry gas via the gas phase transfer line L20. The gas supply line L30 can supply dry gas to the upper level of the liquefied gas storage tank via the gas phase transfer line L20 and the gas phase manifold 22. Dry gas, which has a temperature relatively higher than the temperature inside the liquefied gas storage tank, can be lighter than the air inside the liquefied gas storage tank and, as it is supplied to the upper level of the liquefied gas storage tank and flows down to the lower level of the liquefied gas storage tank, can push the air inside the liquefied gas storage tank to the lower level of the liquefied gas storage tank.

[0116] Regardless of the dry gas supply method, the dry gas supply unit can supply dry gas until the dew point inside the liquefied gas storage tank drops below -20°C. If the dew point inside the liquefied gas storage tank drops below -20°C, the dry gas supply unit must be within 1m 3 It can contain less than 1g of moisture per unit, and within this moisture content range, it can minimize the impact on the loading of liquefied gas.

[0117] In the evaporation gas treatment process according to this embodiment, the target may be a liquefied gas carrier or a liquefied gas propulsion ship, and the target liquefied gas storage tank may be, but is not limited to, a pressure vessel.

[0118] The bunkering vessel according to this embodiment can adjust the supply position of the dry gas in the liquefied gas storage tank in consideration of the dry gas supplied from the bunkering vessel and the temperature or specific gravity conditions inside the target liquefied gas storage tank. When the dry gas is relatively hot, it is injected from the upper part of the liquefied gas storage tank to push the internal air to the lower part, and when the dry gas is relatively cold, it is injected from the lower part of the liquefied gas storage tank to push the internal air to the upper part, utilizing the piston effect to more effectively remove moisture inside the liquefied gas storage tank.

[0119] Next, an embodiment of an inerting process for supplying an inert gas will be described with reference to Figures 4 and 5. The inerting process may be a process of supplying an inert gas to a liquefied gas storage tank via manifolds 20 and 20' to remove explosive gases from the liquefied gas storage tank before loading the liquefied gas into the target liquefied gas storage tank. Preferably, the inerting process may be a process of removing dry gas injected into the liquefied gas storage tank after the drying process. Hereinafter, explosive gas refers to a gas that includes oxygen and can cause a combustion reaction that makes the liquefied gas combustible when the liquefied gas is loaded.

[0120] After the drying process, the liquefied gas storage tank may be filled with dry gas. If the dry gas is dry air, the dry air may have an oxygen concentration of approximately 20% (v / v). The dry air may also contain a small amount of moisture. Through the inerting process, the oxygen concentration in the liquefied gas storage tank can be reduced to a safe level and moisture can be further removed, ensuring safety during the bunkering process.

[0121] 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 a nitrogen generator that generates nitrogen gas and an inert gas generator (IGG) that can burn heavy oil.

[0122] When the inert gas supply unit is a nitrogen gas generator, the inert gas supply unit may separate nitrogen gas by using a separation membrane to separate nitrogen gas by utilizing the partial pressure difference between components in air, or by pressure swing adsorption (PSA) using an adsorption tower. In the nitrogen gas separation process, nitrogen gas may be separated and supplied at a low temperature of about -30°C.

[0123] When the inert gas supply unit is an inert gas generator capable of burning heavy oil, the inert gas supply unit may further combust exhaust gas discharged from an engine that uses heavy oil as fuel, or may directly combust the heavy oil to generate inert gas. In the present invention, the engine may be a propulsion engine that uses heavy oil, and the heavy oil may be at least one of, but is not limited to, HFO (Heavy Fuel Oil), MDO (Marine Diesel Oil), and MGO (Marine Gas Oil).

[0124] 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.

[0125] The inert gas supply unit may produce inert gas using electricity generated by the power generation engine G / E of the bunkering ship.

[0126] The inert gas supply unit produces inert gas and supplies it to the liquefied gas storage tank via the gas supply line L30. Since the inerting process is performed before loading, the inert gas supply unit supplies the inert gas via the liquefied gas transfer line and the manifolds 20 and 20'. The gas supply line L30 supplies the inert gas to the manifolds 20 and 20' via at least one of the liquid phase transfer line L10, the gas phase transfer line L20, and the spray line L11.

[0127] At this time, the gas supply line L30 can supply dry gas via the liquid phase transfer line L10 or the gas phase transfer line L20 depending on the type of inert gas.

[0128] Referring to FIG. 4, if the inert gas supplied from the inert gas supply unit is generated by burning heavy oil, the gas supply line L30 can supply the inert gas via the liquid phase transfer line L10. If the inert gas is 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 can supply the inert gas to the lower level of the target liquefied gas storage tank via the liquid phase transfer line L10 and the liquid phase manifold 21. The relatively heavy inert gas is supplied to the lower level of the liquefied gas storage tank, allowing the dry gas inside the liquefied gas storage tank to be pushed to the upper level of the liquefied gas storage tank.

[0129] Referring to FIG. 5, if the inert gas supplied from the inert gas supply unit is nitrogen gas, the gas supply line L30 can supply the inert gas via the gas phase transfer line L20. If the inert gas is nitrogen gas, the inert gas may be lighter than the gas inside the target liquefied gas storage tank. The gas supply line L30 can supply the inert gas to the upper level of the target liquefied gas storage tank via the gas phase transfer line L20 and the gas phase manifold 22. The relatively light inert gas is supplied to the upper level of the liquefied gas storage tank and, as it flows down to the lower level of the liquefied gas storage tank, can push the dry gas inside the liquefied gas storage tank to the lower level of the liquefied gas storage tank.

[0130] Regardless of the type of inert gas, the inert gas supply unit can supply inert gas when the dew point inside the target liquefied gas storage tank is lower than -20°C, and can supply inert gas until the dew point inside the liquefied gas storage tank is lower than -40°C. If the dew point inside the liquefied gas storage tank is lower than -40°C, the inert gas supply unit must be within 1m 3 It may contain less than 0.1 g of water per serving.

[0131] In addition, the inert gas supply unit can supply inert gas until the oxygen concentration inside the liquefied gas storage tank falls below 2% (v / v). When the oxygen concentration inside the liquefied gas storage tank falls below 2% (v / v), the risk of explosion inside the liquefied gas storage tank is significantly reduced.

[0132] In the evaporation gas treatment process according to this embodiment, the target may be a liquefied gas carrier, and the target liquefied gas storage tank may be, but is not limited to, a pressure vessel.

[0133] The bunkering vessel according to this embodiment can remove moisture and oxygen from inside the liquefied gas storage tank by using the inert gas generated inside the bunkering vessel, and can more effectively remove moisture and oxygen from inside the liquefied gas storage tank by adjusting the supply position in the liquefied gas storage tank according to the characteristics of the inert gas and utilizing the piston effect.

[0134] 6 and 7 are conceptual diagrams showing the gassing-up process before bunkering to a liquefied gas carrier equipped with 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, etc., and the same content as that described with reference to FIG. 1 shall be substituted for the content of the previous embodiment.

[0135] The bunkering vessel of this embodiment can supply liquefied gas to the liquefied gas storage tank of the liquefied gas carrier while the bunkering vessel is connected to the target, and can receive exhaust gas discharged from the liquefied gas carrier.

[0136] The gassing process can be divided into two stages depending on the composition inside the liquefied gas storage tank of the liquefied gas carrier. For example, the gassing process can be divided into the first stage, in which liquefied gas is supplied until the liquefied gas concentration in the gas phase inside the liquefied gas storage tank reaches 5% (v / v), and the second stage, in which liquefied gas is supplied until the liquefied gas concentration in the gas phase inside the liquefied gas storage tank reaches more than 99% (v / v).

[0137] The gassing-up process may be a process of removing gas stored in a liquefied gas storage tank by supplying at least a portion of the liquefied gas to the liquefied gas storage tank through the manifolds 20, 20′ before loading the liquefied gas into the liquefied gas storage tank of the liquefied gas carrier. Preferably, the gassing-up process may be a process of removing inert gas injected into the liquefied gas storage tank after the inerting process. This may involve supplying liquefied gas at a flow rate that is relatively smaller than the flow rate during full-scale loading of the liquefied gas.

[0138] Before loading the liquefied gas, the liquefied gas storage tank may be filled with an inert gas. The inert gas may contain carbon dioxide. The carbon dioxide contained in the inert gas may be sublimated by the cryogenic liquefied gas as the liquefied gas is subsequently loaded, potentially damaging the liquefied gas storage tank or components such as a pump installed inside the liquefied gas storage tank. The gassing process removes the carbon dioxide from the liquefied gas storage tank, thereby protecting the liquefied gas storage tank and other equipment.

[0139] The bunkering vessel can supply liquefied gas to the liquefied gas storage tank of the liquefied gas carrier using the liquefied gas transfer line. Since the gassing-up process is performed before loading, the bunkering vessel can supply liquid-phase liquefied gas through the liquefied gas transfer line and manifolds 20, 20'. The bunkering vessel can supply liquid-phase liquefied gas to the liquid-phase manifold 21 through at least one of the liquid-phase transfer line L10 and the spray line L11.

[0140] More specifically, the bunkering vessel can supply liquid-phase liquefied gas to the liquefied gas vaporizer of the liquefied gas carrier via the liquid-phase manifold 21. The liquefied gas vaporized in the liquefied gas vaporizer can be injected in gas phase into the liquefied gas storage tank of the liquefied gas carrier. As the gas-phase liquefied gas is injected into the liquefied gas storage tank, gas stored inside the liquefied gas storage tank can be discharged. This discharged gas can be an inert gas, and can be supplied to the bunkering vessel via the gas-phase manifold 22 of the bunkering vessel.

[0141] The bunkering vessel can receive and treat exhaust gas discharged from the liquefied gas carrier via the gas phase transfer line L20.

[0142] Referring to FIG. 6, the initial stage of gassing-up, i.e., the first stage, can be indicated when the majority of the exhaust gas discharged from the liquefied gas storage tank as the liquefied gas is vaporized and injected into the liquefied gas storage tank is inert gas. As described above, the vapor phase transfer line L20 can supply the exhaust gas to at least one of the gas combustion unit GCU and the vent 13 until the liquefied gas concentration in the gas phase inside the liquefied gas storage tank reaches 5% (v / v). For example, the vapor phase transfer line L20 can supply the exhaust gas to the gas combustion unit GCU when the concentration of the inert gas contained in the exhaust gas is equal to or less than a predetermined value, or to the vent 13 when the concentration of the inert gas is equal to or greater than a predetermined value. The predetermined value can be approximately 95%.

[0143] The gas phase transfer line L20 can supply the exhaust gas to the gas combustion unit GCU via a liquefied gas supply line L22 for treatment. The liquefied gas supply line L22 is equipped with an HD compressor 18, which can pressurize the inert gas to the pressure required by the gas combustion unit GCU before supplying it to the gas combustion unit GCU. Alternatively, the gas phase transfer line L20 can supply the exhaust gas to a vent section 13 and discharge it to the outside for treatment.

[0144] Referring to Figure 7, the gas phase transfer line L20 can supply the exhaust gas to at least one of the gas combustion unit GCU and the buffer tank 40 when the concentration of inert gas contained in the exhaust gas is less than a predetermined value. Figure 7 can show a second stage after the initial gassing-up, i.e., when the majority of the exhaust gas discharged from the liquefied gas storage tank as the liquefied gas is vaporized and injected is liquefied gas in gas phase or evaporated gas. The gas phase transfer line L20 can supply 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), or to the buffer tank 40 when the liquefied gas concentration is approximately 90% (v / v).

[0145] The gas phase transfer line L20 can supply the exhaust gas to the gas combustion unit GCU for treatment via a liquefied gas supply line L22 equipped with an HD compressor 18. Alternatively, the gas phase transfer line L20 can supply the exhaust gas to the buffer tank 40 for treatment via a liquefied gas supply line L22 equipped with an LD compressor 17. When the exhaust gas is supplied to the buffer tank 40, the exhaust gas can be separated into condensate components as it passes through a gas-liquid separator 16 upstream of the LD compressor 17. When the buffer tank 40 is filled to capacity, the exhaust gas can also be supplied to the gas combustion unit GCU for treatment.

[0146] As the exhaust gas pressurized by the LD compressor 17 is supplied to the buffer tank 40 and expands, at least a portion of the exhaust gas may condense or liquefy to form a liquid-phase liquefied gas. The buffer tank 40 may supply the liquid-phase liquefied gas to the liquid-phase transfer line L10 using a pump 41, and the liquid-phase liquefied gas may be returned to the bunkering tank 10 or supplied again to the liquid-phase manifold 21.

[0147] The bunkering vessel according to this embodiment supplies liquefied gas to a liquefied gas carrier equipped with a liquefied gas vaporizer, and injects the liquefied gas vaporized by the liquefied gas vaporizer into a liquefied gas storage tank to remove inert gas from the liquefied gas storage tank. In this case, the treatment method for the exhaust gas discharged from the liquefied gas storage tank can be varied depending on the degree of inert gas removal. In the second stage gassing-up process in which the liquefied gas content is high, the exhaust gas can be supplied to a buffer tank to reuse the liquefied gas in the exhaust gas.

[0148] 8 and 9 are conceptual diagrams showing the gassing-up process before bunkering in a liquefied gas propelled ship not equipped with a liquefied gas vaporizer in a bunkering ship according to an embodiment of the present invention. The bunkering ship may include a bunkering tank 10, a liquefied gas vaporizer 15, a manifold 20, a liquefied gas transfer line, a buffer tank 40, etc., and the same content as that described with reference to FIG. 1 shall be substituted for the content of the previous embodiment.

[0149] The bunkering vessel of this embodiment can supply liquefied gas to the liquefied gas storage tank of the liquefied gas propelled vessel while the bunkering vessel is connected to the target, and can receive exhaust gas discharged from the liquefied gas carrier.

[0150] The gassing process can be divided into a first stage and a second stage depending on the composition inside the liquefied gas storage tank of the liquefied gas carrier, and the criteria for dividing each stage are the same as those in the above-mentioned embodiment.

[0151] The gassing-up process may involve supplying at least a portion of the liquefied gas to the liquefied gas storage tank via manifolds 20, 20' to remove the gas stored inside the liquefied gas storage tank before loading the liquefied gas into the liquefied gas storage tank of the liquefied gas carrier.

[0152] The bunkering vessel can supply liquefied gas to the liquefied gas storage tank of the liquefied gas carrier using a liquefied gas transfer line. Since the gassing-up process is performed before loading, the bunkering vessel can supply liquefied gas via the liquefied gas transfer line and manifolds 20, 20'. In this case, the bunkering vessel can extract liquid-phase liquefied gas through at least one of the liquid-phase transfer line L10 and the spray line L11 and supply it to the liquefied gas vaporization line L15 branching off from the liquid-phase transfer line L10. More specifically, the liquefied gas vaporization line L15 branches off from the liquefied gas supply line L14, and the liquid-phase liquefied gas supplied to the liquid-phase transfer line L10 can be supplied to the liquefied gas vaporization line L15 via the liquefied gas supply line L14.

[0153] The liquefied gas vaporization line L15 may be equipped with a liquefied gas vaporizer 15 that vaporizes the liquid-phase 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 vapor-phase manifold 22, and can vaporize the liquefied gas and supply it to the liquefied gas-propelled ship. The liquefied gas vaporizer 15 can vaporize the liquefied gas in the same manner as the forced vaporizer 14 described above.

[0154] The bunkering vessel can vaporize the liquefied gas in advance using the liquefied gas vaporizer 15 installed in the bunkering vessel, and then supply the gaseous liquefied gas to the liquefied gas storage tank of the liquefied gas propulsion vessel through the gaseous phase manifold 22. The liquefied gas propulsion vessel can receive the gaseous liquefied gas through the gaseous phase manifold 22 and supply it directly to the liquefied gas storage tank to perform the gassing-up process.

[0155] As gas-phase liquefied gas is injected into the liquefied gas storage tank of the liquefied gas propulsion ship, the gas stored inside the liquefied gas storage tank may be discharged. This discharged gas may be an inert gas and may be supplied to the bunkering ship via the liquid phase manifold 21 of the bunkering ship. The gas-phase liquefied gas may have a relatively low specific gravity compared to the discharged gas and may be relatively light. The relatively light gas-phase liquefied gas may be injected into the upper level of the liquefied gas storage tank of the liquefied gas propulsion ship, and the relatively heavier inert gas may be pushed out to the lower level.

[0156] The bunkering vessel can receive and treat exhaust gas discharged from the liquefied gas propelled vessel via the gas phase transfer line L20.

[0157] Referring to Figure 8, the liquid phase transfer line L10 can supply the exhaust gas to at least one of the gas combustion unit GCU and the vent section 13 when the concentration of inert gas contained in the exhaust gas is equal to or greater than a predetermined value. Figure 8 can show the initial stage of gassing-up, i.e., the first stage, in which most of the exhaust gas discharged from the liquefied gas storage tank is inert gas. As described above, the liquid phase transfer line L10 can supply the exhaust gas to at least one of the gas combustion unit GCU and the vent section 13 until the liquefied gas concentration in the gas phase inside the liquefied gas storage tank reaches 5% (v / v).

[0158] The liquid phase transfer line L10 can supply the exhaust gas to the gas combustion unit GCU via the liquefied gas supply line L22 for treatment. For example, the liquefied gas supply line can be equipped with an HD compressor 18 to pressurize the inert gas to the pressure required by the gas combustion unit GCU before supplying it to the gas combustion unit GCU. Alternatively, the liquid phase transfer line L10 can supply the exhaust gas to the vent section 13 and discharge it to the outside for treatment.

[0159] Referring to FIG. 9, the liquid-phase transfer line L10 can supply the exhaust gas to at least one of the gas combustion unit GCU and the buffer tank 40 when the concentration of inert gas contained in the exhaust gas is less than a predetermined value. FIG. 9 can show a second stage after the initial gassing-up, i.e., when the majority of the exhaust gas discharged from the liquefied gas storage tank is gas-phase liquefied gas or evaporated gas as the liquefied gas is vaporized and injected. As described above, the liquid-phase transfer line L10 can supply the exhaust gas to the gas combustion unit GCU when the gas-phase liquefied gas concentration inside the liquefied gas storage tank exceeds 5% (v / v), or to the buffer tank 40 when the liquefied gas concentration is approximately 90% (v / v). The gas-phase transfer line L20 can supply the exhaust gas to the gas combustion unit GCU via the liquefied gas supply line L22 equipped with the HD compressor 18 for treatment. Alternatively, the gas phase transfer line L20 can supply the exhaust gas to the buffer tank 40 via a liquefied gas supply line L22 equipped with an LD compressor 17 for treatment. When the exhaust gas is supplied to the buffer tank 40, the exhaust gas can be separated into condensate components while passing through a gas-liquid separator 16 upstream of the LD compressor 17.

[0160] As the exhaust gas pressurized by the LD compressor 17 is supplied to the buffer tank 40 and expands, at least a portion of the exhaust gas is condensed or liquefied to form a liquid-phase liquefied gas. The buffer tank 40 can supply the liquid-phase liquefied gas to the liquid-phase transfer line L10 using a pump 41, and the liquid-phase liquefied gas can be returned to the bunkering tank 10 or supplied to the gas-phase manifold 22 again via the liquefied gas vaporizer 15.

[0161] The bunkering vessel according to this embodiment can inject gaseous liquefied gas into a liquefied gas carrier that does not have a liquefied gas vaporizer using a liquefied gas vaporizer installed in the bunkering vessel, thereby removing inert gas from the liquefied gas storage tank. In this case, the treatment method for the exhaust gas discharged from the liquefied gas storage tank can be varied depending on the degree of inert gas removal, and in the second stage gassing-up process in which the liquefied gas content is high, the exhaust gas can be supplied to a buffer tank to reuse the liquefied gas in the exhaust gas.

[0162] 10 is a conceptual diagram showing the 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, etc., and the same content as that described with reference to FIG. 1 shall be substituted for the content of the previous embodiment.

[0163] The bunkering vessel according to this embodiment can lower the internal temperature of the liquefied gas storage tank by supplying a small amount of liquefied gas to the target liquefied gas storage tank while the bunkering vessel is connected to the target.

[0164] The cool-down process may involve supplying a small amount of cryogenic liquefied gas in liquid phase to the liquefied gas storage tank to remove gas stored inside the liquefied gas storage tank before loading liquefied gas into the target liquefied gas storage tank. Preferably, the bunkering vessel may supply liquefied gas to the target liquefied gas storage tank after the gassing-up process and receive a supply of relatively high-temperature liquefied gas in vapor phase discharged from the liquefied gas storage tank.

[0165] More specifically, the bunkering vessel can receive a supply of relatively high temperature liquefied gas from the liquefied gas storage tank in the early stages of cool-down, and then receive a supply of relatively low temperature liquefied gas thereafter.

[0166] Before loading liquefied gas, the liquefied gas storage tank may be filled with gaseous liquefied gas, which is relatively hotter than the liquid liquefied gas. The cool-down process is performed to reduce the amount of liquefied gas that evaporates due to the high-temperature gaseous liquefied gas when loading the liquefied gas. Furthermore, if extremely low-temperature liquid liquefied gas is suddenly injected into the liquefied gas storage tank during loading, it may damage components such as the barrier structure and pump inside the liquefied gas storage tank. The cool-down process reduces the temperature inside the liquefied gas storage tank to a temperature similar to that of the liquid liquefied gas, thereby protecting the liquefied gas storage tank and other equipment.

[0167] The bunkering vessel can supply liquefied gas to the target liquefied gas storage tank 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 manifolds 20, 20'. At this time, the bunkering vessel can extract liquid-phase liquefied gas through at least one of the liquid-phase transfer line L10 and the spray line L11, and supply the liquefied gas to the liquefied gas storage tank through the liquid-phase manifold 21.

[0168] As the liquid-phase liquefied gas is injected into the target liquefied gas storage tank via the liquid-phase manifold 21, the liquid-phase liquefied gas can push the gas-phase liquefied gas inside the liquefied gas storage tank to the upper part of the liquefied gas storage tank. Specifically, the liquid-phase liquefied gas is injected into the target liquefied gas storage tank via the liquid-phase manifold 21, and may be sprayed via a spray provided on the upper part of the liquefied gas storage tank.

[0169] The bunkering ship can receive gas-phase liquefied gas discharged from the liquefied gas storage tank via the gas-phase manifold 22. The bunkering ship can supply the gas-phase liquefied gas supplied from the liquefied gas storage tank via the gas-phase transfer line L20 to at least one of the gas combustion unit GCU and the buffer tank 40 for treatment. The process of supplying the gas-phase liquefied gas to at least one of the gas combustion unit GCU and the buffer tank 40 via the liquefied gas supply line L22 and the treatment process therein are substituted for those in the above-described embodiment.

[0170] The bunkering vessel can supply liquefied gas in liquid phase until the temperature inside the liquefied gas storage tank drops below -130°C.

[0171] In the evaporative gas treatment 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.

[0172] The bunkering vessel according to this embodiment supplies liquid-phase liquefied gas to the upper part of the liquefied gas storage tank through a spray, and can adjust the temperature inside the liquefied gas storage tank to suit loading. At this time, the discharged gas has a high content of liquefied gas, and can be supplied to a buffer tank so that the liquefied gas in the discharged gas can be reused.

[0173] 11 is a conceptual diagram showing the 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, etc., and the same content as that described with reference to FIG. 1 shall be substituted for that described in the previous embodiment.

[0174] The bunkering vessel according to this embodiment can supply liquefied gas to the target liquefied gas storage tank while the bunkering vessel is connected to the target. Through the above process, the inside of the target liquefied gas storage tank can be in a condition suitable for loading cryogenic liquefied gas.

[0175] The bunkering vessel can supply liquid-phase liquefied gas to the target liquefied gas storage tank using the liquefied gas supply line and manifolds 20, 20'. Specifically, the bunkering vessel can extract liquefied gas from the bunkering tank 10 via the liquid-phase transfer line L10 and supply it to the liquefied gas storage tank via the liquid-phase manifold 21.

[0176] The target liquefied gas storage tank may be filled with relatively low-temperature gas-phase liquefied gas supplied during the cool-down process. The bunkering vessel may receive the gas-phase liquefied gas discharged from the liquefied gas storage tank via the gas-phase manifold 22. The bunkering vessel may supply the gas-phase liquefied gas supplied from the liquefied gas storage tank via the gas-phase transfer line L20 to at least one of the gas combustion unit GCU and the buffer tank 40 for treatment. The process of supplying the gas-phase liquefied gas to at least one of the gas combustion unit GCU and the buffer tank 40 via the liquefied gas supply line L22 and the treatment process therein may be substituted for those in the above-described embodiments.

[0177] In the evaporative gas treatment 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.

[0178] The unloading process in the bunkering vessel can be performed by reversing the loading process. The bunkering vessel can extract liquefied gas stored in the liquefied gas storage tank through the liquid phase manifold 21. When performing the loading process on the liquefied gas carrier vessel, the discharged gas phase liquefied gas can be treated in the liquefied gas carrier vessel or can be supplied to the bunkering vessel for treatment.

[0179] The bunkering vessel of this embodiment can load liquid-phase liquefied gas onto the target ship, and at the same time, supply gas-phase liquefied gas discharged from the liquefied gas storage tank to a buffer tank, allowing the liquefied gas to be reused.

[0180] The liquefied gas transfer line may be connected to liquefied gas supply lines L14 and L22. Specifically, the liquefied gas supply line L22 may branch off from the gas phase transfer line L20 and supply gas phase liquefied gas to at least one of a gas combustion unit (GCU), a power generation engine (G / E), and a buffer tank 40. The gas combustion unit GCU may combust and treat the liquefied gas, then discharge it outside the bunkering vessel for treatment. The power generation engine G / E may generate electricity using the liquefied gas as fuel. Preferably, the power generation engine G / E may use the gas phase liquefied gas as fuel. The buffer tank 40 may temporarily store the liquefied gas and then supply it to a location where it is needed, and may temporarily store the gas phase liquefied gas. The buffer tank 40 may separate the supplied liquefied gas into liquid and gas phases and extract them.

[0181] The liquefied gas supply line L14 branches off from at least one of the liquid-phase transfer line L10 and the spray line L11, vaporizes the liquid-phase liquefied gas, and then transmits it to the liquefied gas supply line L22. The liquefied gas supply line L14 is equipped with a forced vaporizer 14, and can vaporize the liquid-phase liquefied gas and transmit it to the liquefied gas supply line L22.

[0182] The liquefied gas supply line L22 receives gas-phase liquefied gas from the liquefied gas transfer line and then branches it again to supply it to at least one of the gas combustion unit GCU, the power generation engine G / E, and the buffer tank 40. Specifically, the gas combustion unit GCU, the power generation engine G / E, and the buffer tank 40 may each require different gas temperature and pressure conditions. A plurality of liquefied gas supply lines L22 may be installed in parallel, and one of the liquefied gas supply lines L22 may be equipped with an LD (low-duty) compressor 17, and another of the liquefied gas supply lines L22 may be equipped with an HD (high-duty) compressor 18. The liquefied gas supply line L22 may supply the liquefied gas to the destination via one of the compressors depending on the type of destination and its corresponding requirements.

[0183] 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 gas phase and a liquid phase, and supplies only the gas-phase liquefied gas to at least one of the gas combustion unit GCU, the power generation engine G / E, and the buffer tank 40 via the liquefied gas supply line L22. The liquid phase separated by the gas-liquid separator 16 is a condensate formed by condensing at least a portion of the gas-phase liquefied gas, and may be returned to the bunkering tank 10 via a condensate return line L23. Preferably, the gas-liquid separator 16 may be provided upstream of the LD compressor 17.

[0184] The liquefied gas supply line L22 may further include a heater 19. The heater 19 may additionally heat the liquefied gas supplied through 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 as it is pressurized by the compressors 17 and 18, but may be lower than the temperature required by the aforementioned destination. The heater 19 may additionally heat the liquefied gas to match the temperature level required by the destination. Preferably, the heater 19 may be provided after the HD compressor 18.

[0185] For example, referring to the drawings, the liquefied gas supply line L22 may branch off from the gas-phase transfer line L20 and then branch off into a plurality of liquefied gas supply lines L22. Any one of the liquefied gas supply lines L22 may be provided with a gas-liquid separator 16 and an LD compressor 17, and may transfer gas-phase liquefied gas to at least one of the gas combustion unit GCU, the power generation engine G / E, and the buffer tank 40. In this case, the liquefied gas supply line L14 joins the gas-liquid separator 16 upstream, and may receive gas-phase liquefied gas and supply it to the gas-liquid separator 16. The other liquefied gas supply line L22 may be provided with an HD compressor 18 and a heater 19, and may transfer heated gas-phase liquefied gas to at least one of the gas combustion unit GCU and the power generation engine G / E.

[0186] 12 is a conceptual diagram showing the gas combustion process after bunkering in a bunkering vessel according to one 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, etc., and the same content as that described with reference to FIG. 1 shall be substituted for the content of the previous embodiment.

[0187] The bunkering vessel can process the liquefied gas stored in the buffer tank 40 during the bunkering process for the target. Specifically, the liquefied gas can evaporate inside the buffer tank 40 to form evaporated gas.

[0188] The bunkering vessel according to this embodiment may further include a power generation engine G / E that generates electricity using liquefied gas as fuel.

[0189] The evaporated gas generated inside the buffer tank 40 can be extracted through a buffer tank extraction line L41 and supplied to the liquefied gas supply line L22. One end of the buffer tank extraction line L41 can be connected to the upper part of the buffer tank 40, and the other end can be connected to the upstream part of the gas-liquid separator 16 in the liquefied gas supply line L22.

[0190] The liquefied gas supplied to the gas-liquid separator 16 can be separated into a gas phase and a liquid phase, and the gas phase liquefied gas can be compressed by the LD compressor 17 via the liquefied gas supply line L22 and supplied to the power generation engine G / E. The liquid phase can be returned to the bunkering tank 10 as condensate via the condensate return line L23.

[0191] The above-described gas combustion process has been described as an example performed after bunkering in the bunkering vessel, but is not limited thereto. If liquefied gas exists inside the buffer tank 40 of the bunkering vessel, the gas combustion process according to this embodiment can be performed in parallel with the following other processes.

[0192] 13 and 14 are conceptual diagrams showing the warming-up process of a target liquefied gas storage tank in a bunkering vessel according to one 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, etc., and the same content as that described with reference to FIG. 1 shall be substituted for the content of the previous embodiment.

[0193] The bunkering vessel of this embodiment unloads liquefied gas from the target liquefied gas storage tank, and then supplies liquefied gas to the liquefied gas storage tank while the bunkering vessel is connected to the target, and can receive exhaust gas discharged from the liquefied gas storage tank.

[0194] During the unloading process of liquefied gas, the flow of liquefied gas accompanying the removal of liquefied gas may cause sloshing within the liquefied gas storage tank, in which the liquid liquefied gas sways. During this process, at least a portion of the liquefied gas may evaporate. Furthermore, as the liquefied gas is removed, the liquefied gas remaining in the liquefied gas storage tank may further evaporate to form evaporated gas. After loading the liquefied gas, the liquefied gas storage tank may be filled with evaporated gas, i.e., liquefied gas in a gas phase at a low temperature. During the warming-up process, relatively high-temperature liquefied gas may be supplied to the liquefied gas storage tank via the manifolds 20 and 20′ to empty the liquefied gas storage tank, thereby raising the temperature inside the liquefied gas storage tank.

[0195] The bunkering vessel can vaporize the liquefied gas using at least one of a heater 19 and a liquefied gas vaporizer 15 provided on the liquefied gas supply line L22 and supply it to the liquefied gas storage tank.

[0196] The bunkering vessel can further heat the evaporated gas supplied via the vapor phase transfer line L20 with the heater 19 and inject it again into the liquefied gas storage tank via the liquid phase manifold 21. The bunkering vessel can also heat the liquefied gas supplied via the liquid phase transfer line L10 with the heater 19 and inject it again into the liquefied gas storage tank via the vapor phase manifold 22.

[0197] In addition, the bunkering ship can vaporize liquefied gas supplied via the liquid phase manifold 21 etc. in the liquefied gas vaporizer 15 and supply it to the liquefied gas storage tank.

[0198] During the warming-up process, depending on the temperature inside the target liquefied gas storage tank, gas phase liquefied gas can be supplied to the target liquefied gas storage tank via liquid phase transfer line L10 or gas phase transfer line L20. The bunkering ship can supply gas phase liquefied gas through liquid phase manifold 21 or gas phase manifold 22, taking into account the temperature inside the liquefied gas storage tank.

[0199] 13, immediately after unloading liquefied gas from a liquefied gas storage tank, the bunkering vessel can supply the liquefied gas to the corresponding liquefied gas storage tank via a liquid phase transfer line L10. Immediately after unloading, the liquefied gas storage tank is filled with low-temperature liquefied gas, so that relatively high-temperature gas phase liquefied gas can be supplied to the lower level of the liquefied gas storage tank via a liquid phase manifold 21, and the low-temperature liquefied gas can be pushed to the upper level of the liquefied gas storage tank. Exhaust gas discharged from the liquefied gas storage tank can be supplied to a gas phase transfer line L20 via a gas phase manifold 22.

[0200] The gas phase transfer line L20 can receive a supply of liquefied gas, which is the exhaust gas discharged from the liquefied gas storage tank, and transmit it to the liquefied gas supply line L22. The liquefied gas can be supplied to the buffer tank 40 via a gas-liquid separator 16 and an LD compressor 17 provided on the liquefied gas supply line L22, or can be supplied to a heater 19 via an HD compressor 18 to be reheated and then injected back into the liquefied gas storage tank via a liquid phase manifold 21.

[0201] 14, the bunkering vessel injects gas-phase liquefied gas into the liquefied gas storage tank, and when the internal temperature of the liquefied gas storage tank rises above a predetermined value, the gas-phase liquefied gas can be supplied to the liquefied gas storage tank via the gas-phase transfer line L20. As the relatively high-temperature gas-phase liquefied gas is stored in the liquefied gas storage tank, the gas-phase liquefied gas can be supplied to the upper liquefied gas stage via the gas-phase manifold 22, and the remaining low-temperature liquefied gas can be pushed to the lower liquefied gas stage. The discharged gas discharged from the liquefied gas storage tank can be supplied to the liquid-phase transfer line L10 via the liquid-phase manifold 21.

[0202] The liquid phase transfer line L10 can receive liquefied gas, which is exhaust gas discharged from a liquefied gas storage tank, and transmit it to the liquefied gas supply line L22. The liquefied gas can be supplied to a heater 19 via an HD compressor 18 installed on the liquefied gas supply line, where it is heated again, and then injected back into the liquefied gas storage tank via a gas phase manifold 22. In this case, liquefied gas can be received from the bunkering tank 10 and supplied to the heater 19 via the HD compressor 18 before being used.

[0203] The bunkering vessel can supply liquefied gas until the internal temperature of the liquefied gas is above -10°C.

[0204] In the warm-up 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.

[0205] The bunkering ship according to this embodiment can protect the liquefied gas storage tank and the equipment installed therein even when the temperature inside the liquefied gas storage tank is increased after unloading and then an inert gas is injected. At this time, the liquefied gas discharged from the liquefied gas storage tank is reheated and injected into the liquefied gas, thereby making the most of the liquefied gas flow rate inside the liquefied gas storage tank and performing the warming-up process.

[0206] 15 is a conceptual diagram showing the gas freeing process of a target liquefied gas storage tank in a bunkering vessel according to one 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., and the same content as that described with reference to FIG. 1 shall be substituted for the content of the previous embodiment.

[0207] The gas-freeing process is similar to the inerting process in that it involves supplying an inert gas to a liquefied gas storage tank. However, the gas-freeing process is performed after unloading liquefied gas from the target liquefied gas storage tank and raising the internal temperature of the liquefied gas storage tank through a warm-up process. The gas-freeing process may involve supplying an inert gas to the liquefied gas storage tank through manifolds 20 and 20′ after the warm-up process, thereby removing the liquefied gas from the liquefied gas storage tank.

[0208] After the warm-up process, the liquefied gas storage tank may be filled with liquefied gas in a gas phase at a relatively high temperature. Through the gas freeing process, the liquefied gas in the liquefied gas storage tank can be extracted, recovered, and used or processed, and an inert gas can be supplied into the liquefied gas storage tank to remove explosive gas from the liquefied gas storage tank. Hereinafter, the explosive gas may be liquefied gas.

[0209] 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 generator that generates nitrogen gas and a combustion device that can burn 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.

[0210] The inert gas supply unit produces inert gas and supplies it to the liquefied gas storage tank via the gas supply line L30. The gas supply line L30 supplies the inert gas to the manifolds 20 and 20' via the liquid phase transfer line L10. The inert gas can be supplied to the lower level of the liquefied gas storage tank via the liquid phase manifold 21. The inert gas is relatively heavier than the liquefied gas, and when supplied to the lower level of the liquefied gas storage tank, it can push the liquefied gas inside the liquefied gas storage tank to the upper level of the liquefied gas storage tank.

[0211] The bunkering vessel can receive and treat exhaust gas discharged from the liquefied gas storage tank when inert gas is injected into the liquefied gas storage tank. The exhaust gas can be a gas-phase liquefied gas and can be supplied to the gas-phase transfer line L20 via the gas-phase manifold 22.

[0212] The bunkering vessel can process liquefied gas supplied from a liquefied gas storage tank by supplying it to at least one of the gas combustion unit GCU, the vent section 13, and the buffer tank 40. The liquefied gas can be supplied to at least one of the gas combustion unit GCU and the buffer tank 40 via the gas phase transfer line L20 and the liquefied gas supply line L22, and can be supplied to the vent section 13 via the gas phase transfer line L20. For example, at the beginning of the gas freeing process, the exhaust gas supplied from the target liquefied gas storage tank may contain approximately 90% (v / v) liquefied gas. In this case, the liquefied gas can be supplied to the buffer tank 40 via the LD compressor 17. As the liquefied gas content in the exhaust gas decreases, it can be supplied to the gas combustion unit GCU via the HD compressor 18. Finally, when the majority of the exhaust gas is an inert gas such as nitrogen gas, it can be supplied to the vent section 13 and discharged.

[0213] The inert gas supply unit can supply inert gas until the liquefied gas concentration inside the liquefied gas storage tank is lower than 2% (v / v). When the liquefied gas concentration inside the liquefied gas storage tank is lower than 2% (v / v), the risk of explosion inside the liquefied gas storage tank is significantly reduced.

[0214] In the evaporation gas treatment 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, but is not limited to, a pressure vessel. When performing a gas freeing process on a liquefied gas carrier, the exhaust gas may be treated on the liquefied gas carrier or may be supplied to a bunkering ship for treatment.

[0215] The bunkering vessel of this embodiment can remove the liquefied gas inside the target liquefied gas storage tank using inert gas generated inside the bunkering vessel, and the liquefied gas can be recovered on the bunkering vessel for processing or reuse.

[0216] 16 and 17 are conceptual diagrams showing the air-rating 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., and the same content as that described with reference to FIG. 1 shall be substituted for the content of the previous embodiment.

[0217] The aerating process is similar to the drying process in that it involves supplying dry gas to a liquefied gas storage tank. However, the aerating process is performed after unloading liquefied gas from the target liquefied gas storage tank and filling the liquefied gas storage tank with inert gas through gas freeing. The aerating process may involve supplying dry gas to the liquefied gas storage tank through manifolds 20 and 20′ after the gas freeing process to remove the inert gas from the liquefied gas storage tank.

[0218] After the gas-freeing process, the liquefied gas storage tank may be filled with an inert gas. The liquefied gas storage tank may be maintained in a filled state with an inert gas, and then the gassing process may be performed again to load the liquefied gas. The aerating process may be performed when personnel need to enter the liquefied gas storage tank for maintenance and upkeep, i.e., to create a breathable environment for personnel. Therefore, aerating may be a process of adjusting the oxygen concentration inside the liquefied gas storage tank to approximately 20% (v / v).

[0219] The gas supply unit 30 may be a dry gas supply unit, and the dry gas may be air containing oxygen but not containing moisture. The dry gas supply unit may produce dry gas using electricity generated by a power generation engine G / E of the bunkering vessel.

[0220] The dry gas supply unit can produce dry gas and supply the dry gas to the liquefied gas storage tank via a gas supply line L30. The gas supply line L30 can supply the dry gas to the manifolds 20, 20' via at least one of the liquid phase transfer line L10 and the vapor phase transfer line L20.

[0221] In this case, the gas supply line L30 can supply dry gas through the liquid phase transfer line L10 or the gas phase transfer line L20 depending on the type of inert gas used in the gas freeing process and filling the inside of the liquefied gas storage tank.

[0222] 16, when the liquefied gas storage tank is filled with inert gas generated by burning heavy oil, the gas supply line L30 can supply dry gas via the gas phase transfer line L20. The gas supply line L30 can supply dry gas to the upper part of the liquefied gas storage tank via the gas phase transfer line L20 and the gas phase manifold 22. The dry gas may be lighter than the inert gas generated by combustion, and can be supplied to the upper part of the liquefied gas storage tank and flow down to the lower part of the liquefied gas storage tank, thereby pushing out the inert gas stored in the liquefied gas storage tank to the lower part of the liquefied gas storage tank.

[0223] 17, when the liquefied gas storage tank is filled with inert gas such as nitrogen gas, the gas supply line L30 can supply dry gas via the liquid phase transfer line L10. The gas supply line L30 can supply dry gas to the lower part of the liquefied gas storage tank via the liquid phase transfer line L10 and the liquid phase manifold 21. The dry gas may be heavier than the relatively low-temperature nitrogen gas, and can therefore push the inert gas to the upper part of the liquefied gas storage tank.

[0224] Regardless of the dry gas supply method, the dry gas supply unit can supply dry gas until the oxygen concentration inside the liquefied gas storage tank reaches 20% (v / v) or more.

[0225] The exhaust gas discharged when dry gas is injected into a liquefied gas storage tank is mostly inert gas, and contains very little or no liquefied gas, so it can be discharged directly from the target and treated.

[0226] In the air-rating 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, but is not limited to, a pressure vessel.

[0227] The bunkering vessel of this embodiment can provide an environment in which people can work inside the liquefied gas storage tank by supplying dry gas when maintenance and repairs are required inside the liquefied gas storage tank after unloading the liquefied gas storage tank.

[0228] The present invention is not limited to the above-described embodiments, and may of course include combinations of the above-described embodiments or combinations of at least one of the above-described embodiments with known technology as further embodiments.

[0229] While the present invention has been described above with reference to the embodiments, these are merely illustrative and do not limit the present invention, and a person skilled in the art will recognize that various combinations, modifications, and applications not exemplified in the embodiments are possible within the scope of the essential technical content of the present invention. Therefore, technical content related to modifications and applications that can be easily derived from the embodiments of the present invention should be construed as being included in the present invention. [Explanation of symbols]

[0230] 10 Bunkering Tank 11 First Pump 12 Second pump 13 Vent section 14 Forced Vaporizer 15 Liquefied gas vaporizer 16 Gas-liquid separator 17 LD Compressor 18 HD Compressor 19 Heater 20, 20' manifold 21 Liquid Phase Manifold 22 Gas Phase Manifold 30 Gas supply unit 40 Buffer Tank 41 Pump L10 Liquid phase 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 removal line

Claims

1. A bunkering vessel for loading or unloading liquefied gas into a target liquefied gas storage tank, a bunkering tank for storing liquefied gas; a manifold provided at the bunkering station of the bunkering vessel for allowing liquefied gas to flow in and out of the bunkering vessel; a liquefied gas transfer line that connects the bunkering tank and the manifold and allows the liquefied gas to flow; a dry gas supply that produces a dry gas; supplying dry gas to the liquefied gas storage tank through the manifold; Before loading the liquefied gas into the liquefied gas storage tank, dry gas is supplied to the liquefied gas storage tank through the manifold to remove moisture from inside the liquefied gas storage tank; The liquefied gas transfer line a liquid phase transfer line for transferring a liquid phase liquefied gas; a gas phase transfer line for transferring the gas phase liquefied gas; a gas supply line that transfers the dry gas supplied from the dry gas supply unit to at least one of the liquid phase transfer line and the gas phase transfer line; The gas supply line When the external temperature of the bunkering vessel is equal to or higher than a predetermined temperature, dry gas is supplied through the liquid phase transfer line; The bunkering vessel is characterized in that, when the external temperature of the bunkering vessel is lower than a predetermined temperature, dry gas is supplied through the gas phase transfer line.

2. A bunkering vessel for loading or unloading liquefied gas into a target liquefied gas storage tank, a bunkering tank for storing liquefied gas; a manifold provided at the bunkering station of the bunkering vessel for allowing liquefied gas to flow in and out of the bunkering vessel; a liquefied gas transfer line that connects the bunkering tank and the manifold and allows the liquefied gas to flow; a dry gas supply that produces a dry gas; supplying dry gas to the liquefied gas storage tank through the manifold; After unloading the liquefied gas from the liquefied gas storage tank, supply dry gas to the liquefied gas storage tank through the manifold to discharge inert gas from the liquefied gas storage tank; The liquefied gas transfer line a liquid phase transfer line for transferring a liquid phase liquefied gas; a gas phase transfer line for transferring the gas phase liquefied gas; a gas supply line that transfers the dry gas supplied from the dry gas supply unit to at least one of the liquid phase transfer line and the gas phase transfer line; The bunkering vessel comprises: When the inert gas is nitrogen gas, a dry gas is supplied through the liquid phase transfer line; When the inert gas is a gas generated by burning heavy oil, a dry gas is supplied through the gas phase transfer line.

3. A bunkering vessel for loading or unloading liquefied gas into a target liquefied gas storage tank, a bunkering tank for storing liquefied gas; a manifold provided at the bunkering station of the bunkering vessel for allowing liquefied gas to flow in and out of the bunkering vessel; a liquefied gas transfer line that connects the bunkering tank and the manifold and allows the liquefied gas to flow; a dry gas supply that produces a dry gas; supplying dry gas to the liquefied gas storage tank through the manifold; Before loading the liquefied gas into the liquefied gas storage tank, dry gas is supplied to the liquefied gas storage tank through the manifold to remove moisture from inside the liquefied gas storage tank; The liquefied gas transfer line a liquid phase transfer line for transferring a liquid phase liquefied gas; a gas phase transfer line for transferring the gas phase liquefied gas; a gas supply line that transfers the dry gas supplied from the dry gas supply unit to at least one of the liquid phase transfer line and the gas phase transfer line; The gas supply line When the internal temperature of the liquefied gas storage tank is equal to or higher than a predetermined temperature, dry gas is supplied through the liquid phase transfer line; A bunkering vessel, characterized in that when the internal temperature of the liquefied gas storage tank is lower than a predetermined temperature, dry gas is supplied through the gas phase transfer line.

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