Gas processing systems and ships containing them

Abstract

To provide a gas processing system and a vessel including the same.SOLUTION: Provided are a gas processing system and a vessel including the same. The gas processing system for transmitting liquid gas from a storage tank of a bunkering vessel to a C type fuel tank provided on a gas propulsion vessel includes: a bunkering line for supplying the liquid gas in the storage tank to the fuel tank; a bunkering management unit for adjusting internal pressure of the storage tank by liquefying evaporation gas in the storage tank by a coolant and returning; and an evaporation gas return line for transmitting the evaporation gas generated in the fuel tank while bunkering through the bunkering line to the bunkering vessel, wherein the bunkering management unit lowers the internal pressure of the storage tank prior to bunkering to be already set pressure or less so that the evaporation gas is transmitted without compression by a separate compressor through the evaporation gas return line by holding the internal pressure of the fuel tank to be inner pressure of the fuel tank or less when bunkering.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas treatment system and a ship including the same.

Background Art

[0002] A ship is a means of transportation that sails across the ocean carrying a large amount of minerals, crude oil, natural gas, or thousands of containers or more. It is made of steel and floats on the waterline by buoyancy and moves by the thrust generated by the rotation of a propeller.

[0003] Such a ship generates thrust by driving an engine or a gas turbine. At this time, the engine uses an oil fuel such as gasoline or diesel to move a piston, rotates a crankshaft by the reciprocating motion of the piston, and rotates a shaft connected to the crankshaft to drive the propeller. On the other hand, the gas turbine uses a method of burning fuel together with compressed air and generating electricity by rotating turbine blades by the temperature / pressure of the combustion air and transmitting power to the propeller.

[0004] However, recently, in an LNG carrier that transports liquefied natural gas (LNG), which is a type of liquefied gas, an LNG fuel supply method that uses LNG as fuel to drive demanders such as engines and turbines has been used. Since LNG is a clean fuel and its reserves are richer than those of oil, the method of using LNG as fuel for demanders has also been applied to ships other than LNG carriers.

[0005] However, unlike diesel oil, LNG has the characteristic that it must be kept at an extremely low temperature in order to maintain a liquid phase during loading / unloading. Therefore, there is a need for research and development of a technology for stably bunkering LNG for ships other than LNG carriers to which the LNG propulsion method is applied.

Summary of the Invention

Problems to be Solved by the Invention

[0006] This invention was created to solve the problems of the prior art described above, and its objective is to realize stable and rapid transfer of liquefied gas during the process of bunkering liquefied gas to a gas-propelled vessel, thereby improving the efficiency of bunkering. [Means for solving the problem]

[0007] A gas treatment system according to one aspect of the present invention is a gas treatment system for transferring liquefied gas from a storage tank of a bunkering vessel to a C-type fuel tank installed on a gas-propelled vessel, comprising: a bunkering line that supplies the liquefied gas from the storage tank to the fuel tank; a bunkering management unit that liquefies the evaporated gas from the storage tank with a refrigerant and returns it to adjust the internal pressure of the storage tank; and an evaporated gas return line that transfers the evaporated gas generated in the fuel tank during bunkering via the bunkering line to the bunkering vessel, wherein the bunkering management unit lowers the internal pressure of the storage tank to a predetermined pressure or lower before bunkering, and maintains the internal pressure of the storage tank below the internal pressure of the fuel tank during bunkering so that the evaporated gas is transferred via the evaporated gas return line without compression by another compressor.

[0008] Specifically, the storage tank may be a membrane-type or C-type tank, and the pre-set pressure may be 0.04 barG or 0.2 barG.

[0009] Specifically, the bunkering management unit includes a reliquefaction device that liquefies the evaporated gas, and the evaporated gas return line can transmit the evaporated gas to the reliquefaction device.

[0010] Specifically, the bunkering management unit can maintain the internal pressure of the storage tank below the internal pressure of the fuel tank by reliquefying the evaporated gas transmitted through the evaporated gas return line during bunkering and returning it to the storage tank.

[0011] Specifically, when bunkering into a fuel tank where the internal pressure before bunkering is the first pressure and the internal pressure decreases due to the inflow of liquefied gas during bunkering, the bunkering management unit can make the internal pressure of the storage tank before and during bunkering less than or equal to the internal pressure of the fuel tank at the time of completion of bunkering.

[0012] Specifically, when bunkering into the fuel tank where the internal pressure before bunkering is at the second pressure and the internal pressure increases due to the generation of evaporated gas during bunkering, the bunkering management unit can make the internal pressure of the storage tank before and during bunkering less than or equal to the internal pressure of the fuel tank at the start of bunkering.

[0013] Specifically, the first pressure can be a pressure that is 0.05 barG to 0.1 barG greater than the previously set pressure, and the second pressure can be a pressure that is less than 0.05 barG to 0.1 barG greater than the previously set pressure.

[0014] Specifically, the first pressure can be between 0.5 barG and 8 barG, and the second pressure can be 0.5 barG or less.

[0015] A gas treatment system according to one aspect of the present invention is a gas treatment system for transferring liquefied gas from a storage tank of a bunkering vessel to a fuel tank provided on a gas-propelled vessel, comprising: a bunkering line that supplies the liquefied gas from the storage tank to the fuel tank; a bunkering management unit that adjusts the internal pressure of the storage tank by compressing, cooling, and depressurizing the evaporated gas from the storage tank without heat exchange with a refrigerant and returning it; and an evaporated gas return line that transfers the evaporated gas generated in the fuel tank during bunkering via the bunkering line to the bunkering vessel, wherein the bunkering management unit either lowers the internal pressure of the storage tank to a predetermined pressure or less before bunkering, and blocks the transfer of evaporated gas via the evaporated gas return line during bunkering so that the fuel tank can be pressurized, or maintains the internal pressure of the storage tank below the internal pressure of the fuel tank so that evaporated gas is transferred via the evaporated gas return line without compression by another compressor.

[0016] Specifically, the storage tank is a membrane-type or C-type tank, and the pre-set pressure can be 0.04 barG or 0.2 barG.

[0017] Specifically, the bunkering management unit includes an evaporative gas heat exchanger that exchanges heat between compressed evaporative gas and evaporative gas discharged from the storage tank, and the evaporative gas return line can transmit evaporative gas between the storage tank and the evaporative gas heat exchanger.

[0018] Specifically, the above-mentioned evaporative gas return line can be provided to transmit the evaporative gas between the storage tank and the evaporative gas heat exchanger, either via or by bypassing the evaporative gas heat exchanger.

[0019] Specifically, the bunkering management unit includes a plurality of low-pressure compressors arranged in parallel to compress the evaporated gas from the storage tank and supply it to the power generation engine, a multi-stage boost compressor located at a branch point between the low-pressure compressors and the power generation engine to compress excess evaporated gas to 150 barG or more, and a pressure reducing valve that reduces the pressure of the evaporated gas compressed by the boost compressor and liquefies it. The evaporated gas heat exchanger can cool the high-pressure evaporated gas between the boost compressor and the pressure reducing valve with the evaporated gas discharged from the storage tank.

[0020] Specifically, the bunkering management unit can operate multiple low-pressure compressors in parallel to draw out evaporated gas from the storage tank in order to lower the internal pressure of the storage tank to a predetermined pressure or lower before bunkering.

[0021] Specifically, the bunkering management unit includes a low-pressure compressor that compresses the evaporated gas from the storage tank and supplies it to the power generation engine, a multi-stage high-pressure compressor installed in parallel with the low-pressure compressor and compressing the evaporated gas from the storage tank to 150 barG or more, and a pressure reducing valve that reduces the pressure of the evaporated gas compressed by the high-pressure compressor and liquefies it. The evaporated gas heat exchanger cools the high-pressure evaporated gas between the high-pressure compressor and the pressure reducing valve with the evaporated gas discharged from the storage tank, and the high-pressure compressor can supply the intermediate stage evaporated gas to the power generation engine.

[0022] Specifically, the bunkering management unit can operate the low-pressure compressor and the high-pressure compressor independently according to the amount of liquefied gas stored in the storage tank.

[0023] A gas treatment system according to one aspect of the present invention is a gas treatment system that transfers liquefied gas from a storage tank of a bunkering ship to a fuel tank provided in a gas-propelled ship, and includes a bunkering line that supplies the liquefied gas in the storage tank to the fuel tank, a bunkering management unit that adjusts the internal pressure of the storage tank by supercooling the liquefied gas in the storage tank with a refrigerant and returning it, and an evaporation gas return line that transfers evaporation gas generated in the fuel tank during bunkering via the bunkering line to the bunkering ship. The bunkering management unit lowers the internal pressure of the storage tank below a preset pressure before bunkering, and either blocks the transfer of evaporation gas via the evaporation gas return line during bunkering so that the fuel tank accumulates pressure, or keeps the internal pressure of the storage tank below the internal pressure of the fuel tank so that evaporation gas is transferred via the evaporation gas return line without being compressed by another compressor.

[0024] Specifically, the storage tank is a membrane type or C-type tank, and the preset pressure can be 0.04 barG or 0.2 barG.

[0025] Specifically, the bunkering management unit includes a supercooling device that supercools the liquefied gas with a refrigerant, and a refrigerant supply unit that supplies the refrigerant to the supercooling device. The refrigerant supply unit can include a refrigerant heat exchanger that cools the refrigerant with liquefied gas or evaporation gas supplied from the storage tank to a power generation engine.

[0026] Specifically, the refrigerant supply unit can include a refrigerant compressor, a refrigerant intermediate heat exchanger that exchanges heat between the compressed refrigerant and the refrigerant heated by the supercooling device, a refrigerant expansion machine that expands the refrigerant that has passed through the refrigerant intermediate heat exchanger after compression, and the refrigerant heat exchanger that cools the compressed refrigerant with liquefied gas or evaporation gas supplied from the storage tank to the power generation engine.

[0027] Specifically, the refrigerant supply unit can include a refrigerant compressor, a refrigerant heat exchanger that exchanges heat between the compressed refrigerant, the refrigerant heated by the subcooling device, and the liquefied gas or evaporated gas supplied to the power generation engine, and a refrigerant expander that expands the refrigerant passing through the refrigerant heat exchanger after compression.

[0028] The gas treatment system according to one aspect of the present invention is characterized in that it has the gas treatment system as a bunkering ship.

Advantages of the Invention

[0029] The gas treatment system according to the present invention and the ship including the same can create a technology for shortening the bunkering time and efficiency in consideration of the generation of evaporated gas from the liquefied gas when transmitting the liquefied gas from a bunkering ship to a gas propulsion ship, and can ensure safe and stable bunkering.

Brief Description of the Drawings

[0030] [Figure 1] It is a process flow chart of the gas treatment system according to the first and second embodiments of the present invention. [Figure 2] It is a conceptual diagram of the gas treatment system according to the first embodiment of the present invention. [Figure 3] It is a graph of the internal pressure change in the gas treatment system according to the first embodiment of the present invention. [Figure 4] It is a conceptual diagram of the gas treatment system according to the second embodiment of the present invention. [Figure 5] It is a graph of the internal pressure change in the gas treatment system according to the second embodiment of the present invention. [Figure 6] It is a process flow chart of the gas treatment system according to the third embodiment of the present invention. [Figure 7] It is a process flow chart of the gas treatment system according to the fourth embodiment of the present invention. [Figure 8] It is a process flow chart of the gas treatment system according to the fifth embodiment of the present invention. [Figure 9]This is a process flowchart of a gas treatment system according to the sixth embodiment of the present invention. [Figure 10] This is a process flowchart of a gas treatment system according to the seventh embodiment of the present invention. [Figure 11] This is a process flowchart of a gas treatment system according to the eighth embodiment of the present invention. [Figure 12] This is a process flowchart of a gas treatment system according to the ninth embodiment of the present invention. [Figure 13] This is a process flowchart of a gas treatment system according to the tenth embodiment of the present invention. [Modes for carrying out the invention]

[0031] The object, particular advantages, and novel features of the present invention will become even clearer from the following detailed description and preferred embodiments relating to the accompanying drawings. It should be noted that, in assigning reference numerals to components in each drawing, the same component has been assigned the same number whenever possible, even if it appears in other drawings. Furthermore, in describing the present invention, if a specific description of the relevant prior art is deemed to unnecessarily obscure the gist of the invention, such detailed description will be omitted.

[0032] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Incidentally, in this specification, the liquefied gas may be LNG, but is not limited thereto, and can include all substances that have a boiling point lower than room temperature, are forcibly liquefied for storage, and have a calorific value.

[0033] Furthermore, in this specification, liquefied gas / evaporated gas is classified based on its state inside the tank, and the name does not necessarily limit it to the liquid phase or gas phase. Also, in this specification, high pressure / low pressure is relative and not limited to numerical values.

[0034] For reference, the first and second embodiments described below through Figures 1 to 5 are based on the idea of ​​reducing the generation of evaporated gas during bunkering by completely reliquefying evaporated gas with a refrigerant to lower the internal pressure of the bunkering vessel's BV tank.

[0035] The following sections will describe each embodiment in detail.

[0036] Figure 1 is a process flowchart of the gas treatment system according to the first and second embodiments of the present invention, Figure 2 is a conceptual diagram of the gas treatment system according to the first embodiment of the present invention, and Figure 3 is a graph of the change in internal pressure in the gas treatment system according to the first embodiment of the present invention.

[0037] Referring to Figures 1 to 3, the gas processing system according to the first embodiment of the present invention is a bunkering system that transmits liquefied gas from a storage tank 110 of a bunkering vessel BV to a fuel tank 210a provided on a gas-powered vessel GFS.

[0038] The present invention may include a bunkering vessel BV equipped with the gas treatment system described below. The present invention also includes a gas-powered vessel GFS whose configuration is specified to embody the gas treatment system. For example, the present invention may include a gas-powered vessel GFS to which the following gas treatment system is applied, wherein a compressor (particularly an H / D compressor) is not provided for returning evaporated gas generated during bunkering to the bunkering vessel BV.

[0039] For reference, a gas-powered vessel (GFS) is a merchant ship other than a liquefied gas carrier, and may be of a type such as a bulk carrier, container ship, or mineral carrier, and may be equipped with a system that supplies liquefied gas or evaporated gas stored in a fuel tank 210a to the propulsion engine 230 via a gas supply line L6 after being compressed / pressurized / heated by a fuel processing unit 220 (pump, compressor, heat exchanger, etc.).

[0040] The gas processing system may include a configuration for supplying liquefied gas from a storage tank 110 to a fuel tank 210a. In this case, the storage tank 110 is a membrane type or a C-type tank, and the liquefied gas can be transmitted to the fuel tank 210a along a bunkering line L1 connecting the storage tank 110 and the fuel tank 210a by a transfer pump 111 provided inside the storage tank 110.

[0041] Furthermore, the gas processing system includes a configuration that returns the evaporated gas generated in the fuel tank 210a to the bunkering vessel BV when liquefied gas is supplied to the fuel tank 210a. In this embodiment, the fuel tank 210a may be a C-type with a design pressure of around 5 barG to 10 barG, and may be installed in various locations such as on the deck or inside the gas-propelled vessel GFS. The evaporated gas generated in the fuel tank 210a is returned to the bunkering vessel BV via the evaporated gas return line L2 and can be transmitted directly or indirectly to the storage tank 110.

[0042] The gas processing system also includes a bunkering control unit 120. The bunkering control unit 120 adjusts the internal pressure of the storage tank 110. For example, it can liquefy the evaporated gas from the storage tank 110 with a refrigerant (such as nitrogen or a mixed refrigerant, without limitation) and return it to the storage tank 110 to lower the internal pressure of the storage tank 110.

[0043] The present invention, by providing the bunkering management unit 120 described in detail below, can improve, compared to conventional methods, aspects such as the generation of evaporated gas in the fuel tank 210a and the return of evaporated gas generated in the fuel tank 210a to the bunkering vessel BV during bunkering, in which liquefied gas from the storage tank 110 is supplied to the fuel tank 210a via the bunkering line L1.

[0044] Specifically, the bunkering control unit 120 can lower the internal pressure of the storage tank 110 to a predetermined pressure or lower before bunkering. For example, the bunkering control unit 120 can lower the internal pressure of the storage tank 110 to a predetermined pressure such as 0.04 barG or 0.2 barG before the liquefied gas is transmitted through the bunkering line L1. Of course, if the internal pressure of the storage tank 110 is already below the predetermined pressure, the liquefaction return of the evaporated gas may be omitted.

[0045] In other words, the present invention reduces the amount of evaporated gas generated when liquefied gas is supplied to the fuel tank 210a by lowering the internal pressure of the storage tank 110 of the bunkering vessel BV in advance, so that the liquefied gas transmitted from the storage tank 110 to the fuel tank 210a is in a sufficiently stable liquid state (for example, a subcooled state).

[0046] Subsequently, once bunkering begins, the bunkering control unit 120 maintains the internal pressure of the storage tank 110 below the internal pressure of the fuel tank 210a. In this case, the evaporated gas generated in the fuel tank 210a does not require compression by another compressor during the process of being transmitted to the bunkering vessel BV via the evaporated gas return line L2. In other words, the present invention enables evaporated gas (NBOG) returned from the gas-propelled vessel GFS to the bunkering vessel BV during the bunkering process to be transmitted without compression (freeflow).

[0047] Specifically, the present invention continuously processes the evaporated gas in the storage tank 110 during the bunkering process to maintain the internal pressure of the storage tank 110 lower than that of the fuel tank 210a, and allows the evaporated gas to be transferred from the fuel tank 210a to the storage tank 110 without compression. This eliminates the need for a high-duty compressor, which was previously installed in gas-powered ships (GFS) for the return of evaporated gas during bunkering. Of course, for this purpose, both the storage tank 110 and the fuel tank 210a are equipped with pressure gauges (not shown) for measuring their internal pressure.

[0048] To realize these effects, the bunkering management unit 120 utilizes a reliquefaction device 122 that liquefies the evaporated gas. Upstream of the reliquefaction device 122, multiple evaporated gas compressors 121 are provided in parallel to back each other up, and downstream of the reliquefaction device 122, a pressure regulating valve 123 and a gas-liquid separator 124 are provided.

[0049] The evaporative gas compressor 121, the reliquefaction device 122, the pressure regulating valve 123, and the gas-liquid separator 124 may be sequentially installed on the pressure regulating line L3 that forms a circulation path with respect to the storage tank 110. This allows the bunkering management unit 120 to compress and liquefy the evaporative gas in the storage tank 110 and return it to the storage tank 110, thereby lowering the internal pressure of the storage tank 110.

[0050] Furthermore, in order to maintain a low internal pressure in the storage tank 110, the present invention may be configured such that the evaporated gas transmitted to the bunkering vessel BV via the evaporated gas return line L2 is transmitted to the reliquefaction unit 122 and returned to the storage tank 110 after reliquefaction, or it may be transmitted to the storage tank 110 by bypassing the reliquefaction unit 122. Alternatively, the evaporated gas transmitted from the gas-propelled vessel GFS may be used to operate the power generation engine 130 for power consumption within the bunkering vessel BV.

[0051] In order to ensure that the internal pressure of the storage tank 110 is less than or equal to the internal pressure of the fuel tank 210a, that is, to ensure that the internal pressure of the fuel tank 210a is higher than that of the storage tank 110, the bunkering control unit 120 can utilize the reliquefaction unit 122 to prevent the evaporated gas transmitted through the evaporated gas return line L2 from immediately flowing into the storage tank 110 and causing an increase in the internal pressure of the storage tank 110.

[0052] In other words, the bunkering management unit 120 can maintain the internal pressure of the storage tank 110 below the internal pressure of the fuel tank 210a by reliquefying the evaporated gas returned during bunkering and returning it to the storage tank 110. At this time, the evaporated gas return line L2 can be configured to merge with the inlet end of the evaporated gas compressor 121, which is upstream of the reliquefaction device 122, or to be directly connected to the reliquefaction device 122. However, if the internal pressure of the fuel tank 210a corresponds to the pressure downstream of the evaporated gas compressor 121, the evaporated gas may be directly transmitted from the evaporated gas return line L2 to the reliquefaction device 122.

[0053] Since the load on the transfer pump 111 increases as the internal pressure of the storage tank 110 decreases, the bunkering management unit 120 can also increase the internal pressure of the storage tank 110 so that when the internal pressure of the storage tank 110 is at or below the internal pressure of the fuel tank 210a, the returned evaporated gas is supplied to the storage tank 110 without reliquefaction.

[0054] Bunkering vessels (BVs) require a relatively large amount of power to operate the reliquefaction unit 122, the evaporative gas compressor 121, the transfer pump 111, etc., while bunkered, and the power generator engine 130 must be running while bunkered. At this time, the power generator engine 130 can receive and consume evaporative gas through the evaporative gas consumption line L4, which branches off from the downstream of the evaporative gas compressor 121 in the pressure adjustment line L3, and so the discharge pressure of the evaporative gas compressor 121 can correspond to the required pressure of the power generator engine 130.

[0055] The power generation engine 130 can consume liquefied gas supplied from the storage tank 110 via the liquefied gas consumption line L5, passing through the fuel supply pump 112 and vaporizer 113. However, in situations such as when the power generation engine 130 is unable to operate, the evaporated gas consumption line L4 may be further connected to a gas combustion device 140 (or a boiler, etc.) to consume the evaporated gas from the storage tank 110.

[0056] The evaporated gas returned via the evaporated gas return line L2 can also be used as fuel for the power generation engine 130, etc. In this case, the evaporated gas return line L2 may be connected upstream of the evaporated gas compressor 121, but is not limited to this.

[0057] The bunkering process will be explained below with reference to Figure 3. For reference, in Figure 3, the solid lines show the change in internal pressure during bunkering of fuel tanks 210a with different initial internal pressures, the inclined dotted lines show the amount of liquefied gas being bunkered, and the horizontal dotted lines represent the internal pressure of storage tank 110.

[0058] First, before bunkering, the gas treatment system can use the reliquefaction unit 122 to lower the internal pressure of the storage tank 110 of the bunkering vessel BV to below a predetermined pressure. At this time, the predetermined pressure is approximately 0.2 barG in Figure 3(A) and approximately 0.04 barG in Figure 3(B).

[0059] Once the internal pressure of the storage tank 110 has dropped sufficiently, the bunkering line L1 is connected between the storage tank 110 and the fuel tank 210a to begin bunkering. The fuel tank 210a may be in a cooled state to receive the cryogenic liquefied gas, but during bunkering, heat penetrates into the fuel tank 210a, causing a large amount of evaporated gas to be generated in the fuel tank 210a due to various factors.

[0060] At this time, in order to protect the fuel tank 210a, the evaporated gas must be returned to the bunkering vessel BV. However, as shown in Figure 3, the present invention makes it possible to ensure that the internal pressure of the storage tank 110 remains below the internal pressure of the fuel tank 210a for the entire duration of bunkering, so that the returned evaporated gas is transmitted without compression.

[0061] The internal pressure of the fuel tank 210a, which is bunkered, may be, for example, 0.2 / 3.0 / 6.5 barG before bunkering. However, as shown in Figure 3(A), if the initial pressure of the fuel tank 210a is 3.0 barG or 6.5 barG, the internal pressure of the fuel tank 210a will gradually decrease as liquefied gas is supplied. Therefore, the gas-powered ship GFS, once bunkering is complete, can be propelled immediately without any treatment of the evaporated gas in the fuel tank 210a. This is because the storage tank 110 reduces its internal pressure before bunkering.

[0062] However, in Figure 3(A), the initial internal pressure of the fuel tank 210a may be 0.2 barG, which is the same as the pre-set pressure of the storage tank 110. In this case, the internal pressure of the fuel tank 210a may increase slightly during the bunkering process due to the generation of evaporated gas by receiving liquefied gas from the storage tank 110, which has the same internal pressure.

[0063] On the other hand, in the case of Figure 3(B), even if the initial internal pressure of fuel tank 210a is 0.2 barG, the internal pressure of storage tank 110 before bunkering is prepared to be a lower 0.04 barG, so it can be confirmed that the internal pressure of all three fuel tanks 210a, each with its own initial internal pressure, decreases during the bunkering process.

[0064] In all of the above cases, the bunkering control unit 120 can maintain a pressure difference between the storage tank 110 and the fuel tank 210a so that the evaporated gas is still returned from the gas-powered vessel GFS to the bunkering vessel BV without compression.

[0065] Specifically, when bunkering into a fuel tank 210a where the internal pressure before bunkering is the first pressure and the internal pressure decreases due to the inflow of liquefied gas during bunkering (in the case where the internal pressure of fuel tank 210a is 3.0 / 6.5 barG in Figure 3(A) and in all cases in Figure 3(B)), the bunkering management unit 120 can make the internal pressure of the storage tank 110 before and during bunkering less than or equal to the internal pressure of fuel tank 210a at the completion of bunkering (approximately 0.5 bar).

[0066] On the other hand, when bunkering into a fuel tank 210a where the internal pressure before bunkering is the second pressure and the internal pressure rises due to the generation of evaporated gas during bunkering (in Figure 3(A), when the internal pressure of fuel tank 210a is 0.2 barG), the bunkering management unit 120 can set the internal pressure of the storage tank 110 before and during bunkering to be less than or equal to the internal pressure of fuel tank 210a at the start of bunkering (0.2 barG).

[0067] In this case, the first pressure is a pressure that is 0.05 barG to 0.1 barG greater than the previously set pressure, and may be between 0.5 barG and 8 barG, while the second pressure is a pressure that is less than 0.05 barG to 0.1 barG greater than the previously set pressure, and may be 0.5 barG or less, but the numerical values ​​are not limited to these.

[0068] As described above, this embodiment reduces the amount of evaporated gas generated in the fuel tank 210a during bunkering by lowering the internal pressure of the storage tank 110 in advance. Furthermore, by maintaining the internal pressure of the storage tank 110 at or below the internal pressure of the fuel tank 210a, the evaporated gas from the fuel tank 210a is returned to the bunkering vessel BV without compression, thereby eliminating the need for the H / D compressor of the gas-propelled ship GFS.

[0069] Figure 4 is a conceptual diagram of a gas treatment system according to a second embodiment of the present invention, and Figure 5 is a graph of the change in internal pressure in the gas treatment system according to a second embodiment of the present invention.

[0070] Referring to Figures 4 and 5 along with Figure 1, the second embodiment of the present invention differs from the above-described embodiment in that the fuel tank 210b is provided in a membrane type. Below, the differences between this embodiment and the above-described embodiment will be explained in detail, and any parts that are omitted from the explanation below will be replaced by the above-described content. This is also the case for the other embodiments described later.

[0071] The gas-powered vessel GFS of this embodiment, as shown in Figure 4, can be a container ship or the like, and can be equipped with a fuel tank 210b on board. In this case, the fuel tank 210b may be of the membrane type. Alternatively, it may be an independent tank having the same or similar design pressure as the membrane type, such as a Type B (e.g., a self-supporting rectangular type SPB).

[0072] The bunkering process of this embodiment will be described below with reference to Figure 5. For reference, as with Figure 3, in Figure 5, the solid line shows the change in internal pressure during bunkering of fuel tanks 210b with different initial internal pressures, the inclined dotted line shows the amount of liquefied gas being bunkered, and the horizontal dotted line represents the internal pressure of the storage tank 110.

[0073] The gas processing system reduces the internal pressure of the storage tank 110 to below a pre-set pressure before bunkering. At this time, the pre-set pressure is approximately 0.2 barG in Figure 5(A) and approximately 0.04 barG in Figure 5(B).

[0074] In the second embodiment, the internal pressure of the storage tank 110 is lowered beforehand before starting bunkering. However, in the second embodiment, as in the first embodiment described above, the internal pressure of the storage tank 110 is kept below the internal pressure of the fuel tank 210b for the entire duration of bunkering, so that evaporated gas is returned from the fuel tank 210b to the bunkering vessel BV without compression by the HD compressor.

[0075] Here, the internal pressure of the fuel tank 210b may be 0.63 / 0.2 / 0.05 barG before bunkering, but in the case where the internal pressure of the fuel tank 210b is 0.63 barG in Figure 5(A) where the internal pressure of the storage tank 110 before bunkering is 0.2 barG, and in the case where the internal pressure of the fuel tank 210b is 0.63 / 0.2 barG in Figure 5(B) where the internal pressure of the storage tank 110 before bunkering is 0.04 barG, the internal pressure of the fuel tank 210b will gradually decrease as liquefied gas is supplied.

[0076] In this case, the internal pressure before bunkering is the first pressure (a pressure of 0.05 barG to 0.1 barG greater than the previously set pressure, specifically 0.5 barG to 1 barG), and bunkering is performed to a fuel tank 210b where the internal pressure decreases due to the inflow of liquefied gas during bunkering. The bunkering management unit 120 can set the internal pressure of the storage tank 110 before and during bunkering to be less than or equal to the internal pressure of the fuel tank 210b at the completion of bunkering (approximately 0.5 bar).

[0077] On the other hand, in Figure 5(A), where the internal pressure of the storage tank 110 before bunkering is 0.2 barG, and in Figure 5(B), where the internal pressure of the fuel tank 210b is 0.05 barG, the internal pressure of the storage tank 110 before bunkering is 0.04 barG, the internal pressure of the fuel tank 210b can increase slightly during the bunkering process due to the generation of evaporated gas while receiving liquefied gas from the storage tank 110, which has the same / similar internal pressure.

[0078] In this case, the internal pressure before bunkering is the second pressure (a pressure less than 0.05 barG to 0.1 barG greater than the previously set pressure, and less than or equal to 0.5 barG), and the fuel tank 210b is bunkered to a fuel tank 210b where the internal pressure rises due to the generation of evaporated gas during bunkering. The bunkering management unit 120 can set the internal pressure of the storage tank 110 before and during bunkering to be less than or equal to the internal pressure of the fuel tank 210b at the start of bunkering (0.2 barG).

[0079] However, in this embodiment, in Figure 5(A) where the internal pressure of the storage tank 110 before bunkering is 0.2 barG, there is a case where the internal pressure of the fuel tank 210b before bunkering is 0.05 barG or less. In this case, the pressure of the storage tank 110, which has fallen to below the previously set pressure before bunkering, is greater than the internal pressure of the fuel tank 210b before bunkering, and a different process is performed than in the first embodiment.

[0080] In this case, during the initial stages of bunkering, the internal pressure of the storage tank 110 is higher than the internal pressure of the fuel tank 210b, so freeflow return of evaporated gas does not occur. Therefore, in this embodiment, the transmission of evaporated gas through the evaporated gas return line L2 is blocked from the start of bunkering until a certain point in time, so that the fuel tank 210b is pressurized.

[0081] When the return of evaporated gas is blocked, the internal pressure of the fuel tank 210b gradually increases due to the generation of evaporated gas. From a certain point in time when the internal pressure of the fuel tank 210b exceeds the internal pressure of the storage tank 110 until the completion of bunkering, the internal pressure of the storage tank 110 is kept below the internal pressure of the fuel tank 210b through the bunkering management unit 120, as in the embodiment described above, thereby allowing evaporated gas to be transmitted without compression via the evaporated gas return line L2.

[0082] In other words, in this embodiment, when bunkering into a fuel tank 210b whose design pressure is at atmospheric pressure, even if the internal pressure of the storage tank 110 is lowered in advance, the internal pressure of the fuel tank 210b may be higher than the internal pressure of the fuel tank 210b before bunkering. To address this, the internal pressure of the fuel tank 210b can be controlled to rise due to pressure accumulation for a certain period of time from the start of bunkering to exceed the internal pressure of the storage tank 110.

[0083] Specifically, the bunkering management unit 120 shuts off the return of evaporated gas from the start of bunkering until a certain point in time, and from that point until the completion of bunkering, it reliquefies the returned evaporated gas and returns it to the storage tank 110, thereby maintaining the internal pressure of the storage tank 110 below the internal pressure of the fuel tank 210b.

[0084] Thus, this embodiment is for implementing bunkering for a membrane-type fuel tank 210b, and implements partial pressure accumulation control of the fuel tank 210b in case the internal pressure of the storage tank 110 is higher than the internal pressure of the fuel tank 210b at the start of bunkering, thereby eliminating the need to use a compressor for the return of evaporated gas.

[0085] For reference, the third and fourth embodiments described below through Figures 6 and 7 are based on the idea of ​​reducing the generation of evaporated gas during bunkering by partially reliquefying evaporated gas through compression / heat exchange / depressurization to lower the internal pressure of the tanks of the bunkering vessel BV.

[0086] The following sections will describe each embodiment in detail.

[0087] Figure 6 is a process flowchart of a gas treatment system according to a third embodiment of the present invention.

[0088] Referring to Figure 6, the gas processing system according to the third embodiment of the present invention may include a bunkering management unit 120 that adjusts the internal pressure of the storage tank 110 by compressing, cooling, and depressurizing the evaporated gas in the storage tank 110 and returning it, instead of (or in addition to) the bunkering management unit 120 which includes a reliquefaction device 122 that liquefies the evaporated gas with a refrigerant and returns it.

[0089] However, in the following embodiments, including this embodiment, the control by which the bunkering management unit 120 lowers the internal pressure of the storage tank 110 to a predetermined pressure (around 0.04 / 0.2 barG) or below before bunkering to block the return of evaporated gas during bunkering, thereby causing the fuel tanks 210a and 210b to accumulate pressure, or by maintaining the internal pressure of the storage tank 110 < the internal pressure of the fuel tanks 210a and 210b so that evaporated gas is transmitted without compression during bunkering, is the same as in the embodiment described above.

[0090] The bunkering control unit 120 includes a low-pressure compressor 121a, a boost compressor 121b, an evaporative gas heat exchanger 125, a pressure reducing valve 123, and a gas-liquid separator 124. The pressure adjustment line L3 forms a circulation path based on the storage tank 110, and the above components can be connected in series in sequence.

[0091] Multiple low-pressure compressors 121a are installed in parallel to compress the evaporated gas from the storage tank 110 and supply it to the power generation engine 130. To this end, the evaporated gas consumption line L4 is branched downstream of the low-pressure compressor 121a and connected to the power generation engine 130, and the low-pressure compressor 121a can be equipped with a discharge pressure suitable for the pressure required by the power generation engine 130.

[0092] The boost compressor 121b is installed in multiple stages and is located at a branch point between the low-pressure compressor 121a and the power generation engine 130 (downstream of the low-pressure compressor 121a with respect to the pressure adjustment line L3), and compresses excess evaporated gas to 150 barG or more.

[0093] This embodiment compresses the evaporated gas without refrigerant heat exchange and then reduces the pressure, utilizing the Joule-Thomson effect for liquefaction. For this purpose, the pressure of the evaporated gas before depressurization must be 150 barG or higher. Therefore, this embodiment includes a low-pressure compressor 121a for supplying evaporated gas to the power generation engine 130, and further includes a boost compressor 121b for liquefaction of the evaporated gas using reduced pressure.

[0094] The evaporative gas heat exchanger 125 can cool the compressed, high-pressure evaporative gas by exchanging heat between the evaporative gas compressed by the boost compressor 121b and the evaporative gas discharged from the storage tank 110. On the other hand, the evaporative gas discharged from the storage tank 110 is slightly heated by the heat exchange in the evaporative gas heat exchanger 125, which increases the inlet temperature of the low-pressure compressor 121a and raises the temperature that the low-pressure compressor 121a must withstand.

[0095] The evaporative gas heat exchanger 125 has a structure that includes at least two streams to exchange heat between a stream of evaporative gas transmitted from the storage tank 110 to the low-pressure compressor 121a and a stream of high-pressure evaporative gas transmitted from the boost compressor 121b to the pressure reducing valve 123.

[0096] In this case, by providing an evaporative gas return line L2 to transmit evaporative gas between the storage tank 110 and the evaporative gas heat exchanger 125, the stream transmitted from the storage tank 110 to the low-pressure compressor 121a can be a mixture of the evaporative gas from the storage tank 110 and the evaporative gas from the fuel tanks 210a and 210b.

[0097] Furthermore, the evaporative gas heat exchanger 125 may further include a stream through which the evaporative gas return line L2 passes, so as to be able to exchange heat with the evaporative gases of fuel tanks 210a and 210b transmitted via the evaporative gas return line L2. That is, after passing through the evaporative gas heat exchanger 125, the evaporative gas return line L2 can merge into a pressure regulating line L3 between the storage tank 110 and the low-pressure compressor 121a.

[0098] However, the evaporative gas return line L2 may be provided to bypass the evaporative gas heat exchanger 125, so the evaporative gas return line L2 is provided to transmit evaporative gas between the storage tank 110 and the evaporative gas heat exchanger 125, either via or by bypassing the evaporative gas heat exchanger 125.

[0099] In this case, the reason why the evaporative gas return line L2 is routed to bypass the evaporative gas heat exchanger 125 is that there is no need to utilize the cold energy of the evaporative gas recovered from the gas-propelled ship GFS, and that there is little or no surplus evaporative gas remaining that is not supplied to the power generation engine 130.

[0100] The pressure reducing valve 123 reduces the pressure of the evaporated gas, which has been compressed by the boost compressor 121b and cooled by the evaporated gas heat exchanger 125, and liquefies it. The pressure reducing valve 123 can reduce the pressure of the evaporated gas, which has been compressed to 150 barG or more and then cooled, to 1 to 10 barG, thereby liquefying at least a portion of the evaporated gas.

[0101] The gas-liquid separator 124 separates the liquefied evaporated gas into gas and liquid phases. The liquid phase (LBOG) is returned to the storage tank 110, and the gas phase (flash gas) can be mixed with the evaporated gas transmitted from the storage tank 110 to the evaporated gas heat exchanger 125.

[0102] Alternatively, the gas phase separated in the gas-liquid separator 124 may not merge with the evaporated gas but instead flow through a separate stream in the evaporated gas heat exchanger 125, undergoing heat exchange, before merging with the evaporated gas upstream of the low-pressure compressor 121a, or being consumed by a power generation engine 130, boiler, or the like.

[0103] In this embodiment, the bunkering management unit 120 is configured as an evaporative gas compressor 121 including multiple low-pressure compressors 121a and boost compressors 121b arranged in parallel. By operating multiple low-pressure compressors 121a in parallel to sufficiently suck out the evaporative gas from the storage tank 110 before bunkering, the internal pressure of the storage tank 110 can be reduced to below a predetermined pressure, thereby quickly achieving a decrease in the internal pressure of the storage tank 110.

[0104] Therefore, this embodiment can improve bunkering efficiency by rapidly and sufficiently lowering the internal pressure of the storage tank 110 before bunkering, thereby reducing the amount of evaporated gas generated in the storage tank 110 during bunkering.

[0105] Figure 7 is a process flowchart of a gas treatment system according to a fourth embodiment of the present invention.

[0106] Referring to Figure 7, the gas treatment system according to the fourth embodiment of the present invention can be configured such that the evaporative gas compressor 121 of the bunkering management unit 120 is different from that of the third embodiment described above.

[0107] In this embodiment, the bunkering management unit 120 includes a low-pressure compressor 121a for supplying evaporated gas to the power generation engine 130 and a high-pressure compressor 121c for liquefying the evaporated gas through the Joule-Thomson effect. However, the low-pressure compressor 121a and the high-pressure compressor 121c can be installed in parallel.

[0108] In this configuration, the high-pressure compressor 121c is connected to an evaporative gas consumption line L4 in the intermediate stage, and the evaporative gas compressed in the intermediate stage is supplied to the power generation engine 130, thereby allowing the low-pressure compressor 121a to be backed up by a portion of the multi-stage high-pressure compressor 121c.

[0109] In this embodiment, the bunkering management unit 120 pressurizes the evaporated gas to 150 barG or higher using a high-pressure compressor 121c, then cools it using the evaporated gas discharged from the storage tank 110 in an evaporated gas heat exchanger 125, and returns it to the storage tank 110 via a pressure reducing valve 123 and a gas-liquid separator 124.

[0110] In this case, the bunkering management unit 120 can independently select and operate the low-pressure compressor 121a and the high-pressure compressor 121c according to the amount of liquefied gas stored in the storage tank 110. For example, when the amount of liquefied gas stored in the storage tank 110 is large (such as in the Laden voyage, which has a large amount of evaporated gas), the high-pressure compressor 121c can be used to supply a portion of the intermediate stage evaporated gas to the power generation engine 130 while reliquefying the final stage evaporated gas and returning it to the storage tank 110. On the other hand, when the amount of liquefied gas stored in the storage tank 110 is small (such as in the Ballast voyage, which has a small amount of evaporated gas), the low-pressure compressor 121a can be used to consume the evaporated gas by the power generation engine 130, etc., and prevent it from being returned to the storage tank 110.

[0111] Thus, in this embodiment, a high-pressure compressor 121c for realizing the liquefaction of evaporated gas using reduced pressure is provided in parallel with a low-pressure compressor 121a for supplying evaporated gas to the power generation engine 130. This allows the high-pressure compressor 121c and the low-pressure compressor 121a to be operated selectively depending on the operating conditions, thereby improving the operating efficiency of the evaporated gas compressor 121.

[0112] For reference, the fifth to seventh embodiments described below with reference to Figures 8 to 10 are based on the idea of ​​supercooling the liquefied gas with a refrigerant and returning it to the bunkering vessel BV, thereby reducing the internal pressure of the tank and minimizing the generation of evaporated gas during bunkering.

[0113] The following sections will describe each embodiment in detail.

[0114] Figure 8 is a process flowchart of a gas treatment system according to a fifth embodiment of the present invention.

[0115] Referring to Figure 8, in the fifth embodiment of the present invention, the gas processing system can adjust the internal pressure of the storage tank 110 by having the bunkering management unit 120 supercool the liquefied gas with the refrigerant and return it, instead of completely reliquefying the evaporated gas with the refrigerant or partially reliquefying it by compressing / cooling / reducing the pressure.

[0116] To this end, the bunkering management unit 120 is equipped with a supercooling device 126 and a refrigerant supply unit 127. The supercooling device 126 can supercool the liquefied gas with a refrigerant, and the temperature of the supercooled liquefied gas may be lower than the boiling point of the liquefied gas at atmospheric pressure (-163°C) (for example, around -170°C).

[0117] The refrigerant supply unit 127 supplies a refrigerant, which is not limited to nitrogen or a mixed refrigerant, to the subcooling device 126 to realize subcooling of the liquefied gas. The refrigerant supply unit 127 includes a refrigerant compressor 1271, a refrigerant cooler 1272, a refrigerant expander 1273, a refrigerant heat exchanger 1274, and an inter-refrigerant heat exchanger 1275, and the refrigerant circulation line L7 connects the above components in order to form a flow path through which the refrigerant circulates.

[0118] The refrigerant compressor 1271 compresses the refrigerant. The pressure of the compressed refrigerant may be around 10 barG, but is not limited to this, and various pressure values ​​may be used to increase the subcooling efficiency.

[0119] The refrigerant cooler 1272 can cool the refrigerant, which is heated while being compressed by the refrigerant compressor 1271, with various types of cold energy. The refrigerant cooler 1272 is installed downstream of the refrigerant compressor 1271, and may be installed at each stage of the refrigerant compressor 1271 if the refrigerant compressor 1271 is installed in multiple stages.

[0120] The refrigerant expander 1273 expands the compressed refrigerant. The refrigerant, which is depressurized by expansion after compression, can have its temperature sufficiently lowered, similar to the case of the pressure reducing valve 123 described above. The expanded refrigerant is then transmitted to the subcooling device 126 and used to subcool the liquefied gas.

[0121] The refrigerant heat exchanger 1274 cools the refrigerant compressed by the refrigerant compressor 1271 with evaporated gas supplied from the storage tank 110 to the power generation engine 130. At this time, the refrigerant heat exchanger 1274 may be installed between the refrigerant compressor 1271 and the subcooling device 126 as shown in the drawing, but alternatively, the refrigerant heat exchanger 1274 can be installed at any point between the refrigerant compressor 1271 and the subcooling device 126, and can also replace the refrigerant cooler 1272.

[0122] The refrigerant-to-refrigerant heat exchanger 1275 can exchange heat between the compressed refrigerant and the refrigerant heated by the subcooling device 126. Specifically, the refrigerant-to-refrigerant heat exchanger 1275 can exchange heat between the refrigerant that has been compressed but not yet expanded, and the refrigerant that has been heated by the subcooling device 126 and is not yet compressed.

[0123] In this embodiment, the refrigerant supply unit 127 is provided in an N2 Bryton cycle and may include a refrigerant-to-refrigerant heat exchanger 1275, but the refrigerant-to-refrigerant heat exchanger 1275 can be omitted at any time.

[0124] Thus, this embodiment utilizes the supercooling return of liquefied gas to lower the internal pressure of the storage tank 110 before bunkering, but by using the cold energy of the evaporated gas supplied to the power generation engine 130 as the refrigerant for supercooling, the energy utilization efficiency can be improved.

[0125] Figure 9 is a process flowchart of a gas treatment system according to the sixth embodiment of the present invention.

[0126] Referring to Figure 9, the gas processing system according to the sixth embodiment of the present invention, compared to the fifth embodiment described above, allows the refrigerant supply unit 127 to cool the refrigerant with liquefied gas supplied from the storage tank 110 to the power generation engine 130.

[0127] The liquefied gas from the storage tank 110 is supplied to the power generation engine 130 via the vaporizer 113. In this embodiment, the liquefied gas to be vaporized is used to cool the refrigerant, thereby increasing the supercooling effect of the liquefied gas before bunkering, and reducing the load on the vaporizer 113 or even eliminating the vaporizer 113 altogether.

[0128] It goes without saying that, unlike the above-described embodiment in which the refrigerant heat exchanger 1274 passes through the refrigerant circulation line L7 and the evaporated gas consumption line L4, the refrigerant heat exchanger 1274 in this embodiment is provided so that it passes through the refrigerant circulation line L7 and the liquefied gas consumption line L5. Furthermore, while the pump for subcooling the liquefied gas in the above-described embodiment can be the transfer pump 111 or another pump, in this embodiment the fuel supply pump 112 can be used as the pump for subcooling the liquefied gas.

[0129] Furthermore, the present invention may also include an embodiment that combines this embodiment with the embodiments described above, in which the refrigerant is cooled by at least one of the evaporated gas and liquefied gas supplied to the power generation engine 130. In this case, the refrigerant heat exchanger 1274 equipped with a refrigerant / liquefied gas / evaporated gas stream may be provided alone, or the refrigerant heat exchanger 1274 of the refrigerant / liquefied gas stream and the refrigerant heat exchanger 1274 of the refrigerant / evaporated gas stream may be provided.

[0130] Figure 10 is a process flowchart of a gas treatment system according to the seventh embodiment of the present invention.

[0131] Referring to Figure 10, the gas processing system according to the seventh embodiment of the present invention can be configured such that the refrigerant heat exchanger 1274 replaces the interrefrigerant heat exchanger 1275.

[0132] In other words, the refrigerant heat exchanger 1274 may consist of at least three streams that exchange heat between compressed refrigerant, refrigerant heated by the subcooling device 126, and liquefied or evaporated gas supplied to the power generation engine 130, and may be provided in a structure that includes heat exchange between refrigerants.

[0133] Therefore, since this embodiment does not include a separate refrigerant-to-refrigerant heat exchanger 1275, the configuration of the refrigerant supply unit 127 can be made more compact.

[0134] For reference, the eighth to tenth embodiments described below with reference to Figures 11 to 13 are designed to efficiently optimize the overall system, taking into account that, unlike gas-propelled vessels (GFS), the power generation engine 130 must be fully operated during bunkering to power the transfer pump 111, and that fuel consumption is high while at anchor.

[0135] Each example will be described in detail below.

[0136] Figure 11 is a process flowchart of a gas treatment system according to the eighth embodiment of the present invention.

[0137] Referring to Figure 11, the gas processing system according to the eighth embodiment of the present invention is similar to the embodiments disclosed above and includes a bunkering management unit 120 that adjusts the internal pressure of the storage tank 110 by utilizing cooling devices 122 and 126 that cool and return the liquefied gas or evaporated gas in the storage tank 110 with a refrigerant.

[0138] This embodiment assumes the operation of cooling devices 122 and 126 that supercool and return the liquefied gas so that the storage tank 110 can receive more evaporated gas, or assumes the operation of cooling devices 122 and 126 that liquefy and return the evaporated gas returned from fuel tanks 210a and 210b, and allows for the direct or indirect derivation of the maximum amount of evaporated gas that the storage tank 110 can receive from the gas-powered ship GFS. However, this maximum amount of evaporated gas returned can be set to less than the flow rate of evaporated gas transmitted through the evaporated gas return line L2 during bunkering.

[0139] In other words, this embodiment makes it possible to prevent all of the evaporated gas returned from the gas-powered ship GFS to the bunkering ship BV from being consumed by operating only the cooling devices 122 and 126. However, as mentioned above, considering that the bunkering ship BV requires more power when docked than the gas-powered ship GFS, this embodiment makes it possible to ensure that the sum of the evaporated gas processing amount of the evaporated gas compressor 121, which compresses the evaporated gas in the storage tank 110 and supplies it to the power generation engine 130, and the maximum amount of evaporated gas returned from the storage tank 110, taking into account the cooling devices 122 and 126, is greater than or equal to the flow rate of evaporated gas returned during bunkering.

[0140] To summarize, the following points can be made:

[0141] Maximum return amount considering cooling devices 122 and 126 < Return amount during bunkering < Maximum return amount considering cooling devices 122 and 126 + Compressor processing amount

[0142] In other words, this embodiment considers that sufficient evaporated gas is supplied to the power generation engine 130 by the evaporative gas compressor 121 during bunkering, and the specifications of the cooling devices 122 and 126 can be reduced, thereby saving CAPEX. However, multiple evaporative gas compressors 121 may be installed in parallel and operated in parallel, and the processing capacity of the compressor in the above formula may be the processing capacity when all parallel evaporative gas compressors 121 are in operation.

[0143] Figure 12 is a process flowchart of a gas treatment system according to the ninth embodiment of the present invention.

[0144] Referring to Figure 12, the gas treatment system according to the ninth embodiment of the present invention optimizes the overall system in a different way than the embodiments described above.

[0145] Specifically, in this embodiment, the maximum amount of evaporated gas returned from the storage tank 110, taking into account the cooling devices 122 and 126, is set to be equal to or greater than the return flow rate of evaporated gas during bunkering. That is, as follows:

[0146] Return amount during bunkering < Maximum return amount considering cooling devices 122 and 126

[0147] In this case, the evaporative gas compressor 121, which compresses the evaporated gas from the storage tank 110 and supplies it to the power generation engine 130, can be omitted. Instead, the liquefied gas from the storage tank 110 can be pumped, vaporized, and supplied to the power generation engine 130.

[0148] In other words, in this embodiment, the specifications of the cooling devices 122 and 126 are set so that the flow rate of the evaporated gas returned during bunkering is covered, and the evaporated gas compressor 121 is omitted, allowing the overall system to be easily configured.

[0149] Figure 13 is a process flowchart of a gas treatment system according to the 10th embodiment of the present invention.

[0150] Referring to Figure 13, the gas treatment system according to the 10th embodiment of the present invention optimizes the system in a different way than the 8th and 9th embodiments described above.

[0151] Specifically, this embodiment is similar to the ninth embodiment in that, considering the cooling devices 122 and 126, the maximum amount of evaporated gas returned from the storage tank 110 is greater than or equal to the return flow rate of evaporated gas during bunkering, while the evaporated gas from the storage tank 110 is supplied to the power generation engine 130, and can be summarized as follows.

[0152] Bunkering return amount < Maximum return amount considering cooling devices 122 and 126 < Maximum return amount considering cooling devices 122 and 126 + Compressor processing amount

[0153] However, in this embodiment, the evaporative gas compressor 121 that compresses the evaporative gas from the storage tank 110 and supplies it to the power generation engine 130 can be provided independently. That is, unlike the eighth embodiment in which the evaporative gas compressors 121 can back up each other, in this embodiment, backup between the evaporative gas compressors 121 is not possible.

[0154] However, in this embodiment, since the maximum amount of evaporated gas returned, taking into account the cooling devices 122 and 126, is already configured to exceed the return flow rate of evaporated gas during bunkering, there is no need to guarantee backup between the evaporated gas compressors 121.

[0155] However, in order to back up the fuel supply to the power generation engine 130, this embodiment can be configured so that at least one of either evaporated gas or liquefied gas can be supplied to the power generation engine 130, so that the supply of evaporated gas is backed up by the supply of liquefied gas.

[0156] Thus, in this embodiment, the evaporated gas compressor 121 is configured independently, while ensuring that the evaporated gas returned during bunkering is adequately processed. However, by configuring it to back up fuel supply with liquefied gas, installation and operating costs can be reduced.

[0157] In addition to the embodiments described above, the present invention also encompasses all embodiments arising from combinations of at least two or more of the above embodiments, or combinations of at least one or more of the above embodiments with known technology.

[0158] Although the present invention has been described in detail through specific embodiments, this is for illustrative purposes only, and it is clear that the present invention is not limited thereto, and that modifications and improvements can be made within the technical concept of the present invention by those with ordinary skill in the art.

[0159] Any simple modifications or changes to the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be clarified by the appended claims. [Explanation of Symbols]

[0160] BV Bunkering Vessels GFS Gas-Powered Ships 110 storage tanks 111 Transfer pump 112 Fuel supply pump 113 Vaporizer 120 Bunkering Management Department 121 Evaporative Gas Compressor 121a Low-pressure compressor 121b Boost Compressor 121c High-Pressure Compressor 122 Reliquefaction equipment, cooling equipment 123 Pressure regulating valve, pressure reducing valve 124 Gas-liquid separator 125 Evaporative gas heat exchanger 126 Supercooling device, cooling device 127 Refrigerant Supply Unit 130 Power generation engine 140 Gas combustion device 210a, 210b fuel tanks 220 Fuel Processing Unit 230 propulsion engine L1 Bunkering Line L2 Evaporation Gas Return Line L3 Pressure Regulating Line L4 Evaporation Gas Consumption Line L5 Liquefied Gas Consumption Line L6 gas supply line L7 Refrigerant Circulation Line

Claims

1. A gas processing system for transferring liquefied gas from a storage tank on a bunkering vessel to a C-type fuel tank on a gas-propelled vessel, A bunkering line that supplies the liquefied gas from the storage tank to the fuel tank, A bunkering management unit adjusts the internal pressure of the storage tank by supercooling the evaporated gas from the storage tank with a refrigerant and returning it, Includes an evaporative gas return line that transmits evaporated gas generated in the fuel tank during bunkering via the bunkering line to the bunkering vessel, The aforementioned bunkering management unit, A supercooling device that supercools liquefied gas with a refrigerant, A refrigerant supply unit that supplies refrigerant to the aforementioned subcooling device, Includes a reliquefaction device that liquefies evaporated gas, A gas processing system characterized by lowering the internal pressure of the storage tank to below a predetermined pressure before bunkering, maintaining the internal pressure of the storage tank below the internal pressure of the fuel tank during bunkering, reliquefying the evaporated gas transmitted through the evaporated gas return line during bunkering and returning it to the storage tank, and ensuring that the evaporated gas is transmitted through the evaporated gas return line without compression by another compressor.

2. The storage tank is a membrane type or a C-type tank. The gas processing system according to claim 1, characterized in that the aforementioned pre-set pressure is 0.04 barG or 0.2 barG.

3. The gas treatment system according to claim 1, characterized in that the evaporated gas return line transmits the evaporated gas to the reliquefaction device.

4. The aforementioned bunkering management unit, The gas treatment system according to claim 1, characterized in that, when bunkering is performed on a fuel tank in which the internal pressure before bunkering is a first pressure and the internal pressure decreases due to the inflow of liquefied gas during bunkering, the internal pressure of the storage tank before and during bunkering is set to be less than or equal to the internal pressure of the fuel tank at the time of completion of bunkering.

5. The aforementioned bunkering management unit, The gas treatment system according to claim 4, characterized in that, when bunkering is performed on a fuel tank where the internal pressure before bunkering is the second pressure and the internal pressure rises due to the generation of evaporated gas during bunkering, the internal pressure of the storage tank before and during bunkering is kept below the internal pressure of the fuel tank at the start of bunkering.

6. The first pressure is equal to or greater than a value that is 0.05 bar to 0.1 bar greater than the previously set pressure. The gas treatment system according to claim 5, characterized in that the second pressure is less than a value 0.05 bar to 0.1 bar greater than the previously set pressure.

7. The first pressure is 0.5 barG to 8 barG. The gas treatment system according to claim 5, characterized in that the second pressure is 0.5 barG or less.

8. A gas processing system for transferring liquefied gas from a storage tank on a bunkering vessel to a fuel tank on a gas-propelled vessel, A bunkering line that supplies the liquefied gas from the storage tank to the fuel tank, A bunkering management unit adjusts the internal pressure of the storage tank by compressing, cooling, and depressurizing the evaporated gas from the storage tank without heat exchange with the refrigerant and returning it. Includes an evaporative gas return line that transmits evaporated gas generated in the fuel tank during bunkering via the bunkering line to the bunkering vessel, The storage tank is a membrane type or a C-type tank. The aforementioned bunkering management unit, Before bunkering, the internal pressure of the storage tank is reduced to below the previously set pressure. A gas processing system characterized by blocking the transmission of evaporated gas through the evaporated gas return line during bunkering, thereby increasing the internal pressure of the fuel tank by allowing it to accumulate pressure up to a certain point in time, and maintaining the internal pressure of the storage tank below the internal pressure of the fuel tank so that evaporated gas is transmitted through the evaporated gas return line without compression by another compressor.

9. The gas treatment system according to claim 8, characterized in that the aforementioned pre-set pressure is 0.04 barG or 0.2 barG.

10. The bunkering management unit includes an evaporative gas heat exchanger that exchanges heat between compressed evaporative gas and evaporative gas discharged from the storage tank. The gas treatment system according to claim 8, characterized in that the evaporative gas return line transmits evaporative gas between the storage tank and the evaporative gas heat exchanger.

11. The aforementioned evaporative gas return line is The gas processing system according to claim 10, characterized in that it is provided to transmit evaporated gas between the storage tank and the evaporated gas heat exchanger via or around the evaporated gas heat exchanger.

12. The aforementioned bunkering management unit, Multiple low-pressure compressors are arranged in parallel and compress the evaporated gas from the storage tank and supply it to the power generation engine, A multi-stage boost compressor is provided at a branching point between the low-pressure compressor and the power generation engine, and compresses the excess evaporated gas to 150 barG or more. The system includes a pressure reducing valve that reduces the pressure of the evaporated gas compressed by the boost compressor and liquefies it, The aforementioned evaporative gas heat exchanger is The gas treatment system according to claim 10, characterized in that the high-pressure evaporated gas between the boost compressor and the pressure reducing valve is cooled with evaporated gas discharged from the storage tank.

13. The aforementioned bunkering management unit, The gas treatment system according to claim 12, characterized in that a plurality of low-pressure compressors are operated in parallel to suck out evaporated gas from the storage tank in order to lower the internal pressure of the storage tank to a predetermined pressure or lower before bunkering.

14. The aforementioned bunkering management unit, A low-pressure compressor that compresses the evaporated gas from the storage tank and supplies it to the power generation engine, A multi-stage high-pressure compressor is provided in parallel with the low-pressure compressor and compresses the evaporated gas from the storage tank to 150 bar G or more. The system includes a pressure reducing valve that reduces the pressure of the evaporated gas compressed by the high-pressure compressor and liquefies it, The aforementioned evaporative gas heat exchanger is Between the high-pressure compressor and the pressure reducing valve, the high-pressure evaporated gas is cooled with the evaporated gas discharged from the storage tank. The gas treatment system according to claim 10, characterized in that the high-pressure compressor supplies the intermediate stage evaporated gas to the power generation engine.

15. The aforementioned bunkering management unit, The gas treatment system according to claim 14, characterized in that the low-pressure compressor and the high-pressure compressor are operated independently according to the amount of liquefied gas stored in the storage tank.

16. A bunkering vessel characterized by having the gas treatment system described in any one of claims 1 to 15.

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