Bin floating body and liquefied gas supply method

Abstract

The floating body for the bunker is provided with: a floating body; a storage tank which is arranged on the floating body and can accommodate liquefied gas; one end of the liquefied gas supply pipeline is arranged in the stock bin tank and extends out of the stock bin tank, and the other end of the liquefied gas supply pipeline can be connected with a fuel tank of another ship; a fuel loading pump which is provided in the silo tank and which is capable of pressure-feeding the liquefied gas in the silo tank from one end of the liquefied gas supply line to the other end thereof; one end of the gas returning pipeline can be connected with the gas pressure feeding pipeline of the fuel tank outside the stock bin tank, the other end of the gas returning pipeline extends into the stock bin tank, and the boil-off gas in the fuel tank, which is fed from the gas pressure feeding pipeline, is fed into a gas phase in the stock bin tank; one end of the bottom receiving pipeline can be connected with a gas pressure feeding pipeline of the fuel tank outside the stock bin tank and extends into the stock bin tank, and the other end of the bottom receiving pipeline reaches the bottom of the stock bin tank.

Description

Technical Field

[0001] The present disclosure relates to a floating body for a silo and a method for supplying liquefied gas.

[0002] This application claims priority to Japanese Patent Application No. 2022-137885 filed in Japan on August 31, 2022, and the contents are incorporated herein by reference. Background Art

[0003] Patent document 1 discloses a structure of a gas handling system for supplying liquefied gas from a storage tank of a fuel loading ship to a fuel tank of a gas propulsion ship. The gas handling system includes a fuel loading pipeline, a boil-off gas return pipeline, and a reliquefaction device (fuel loading management unit). The fuel loading pipeline supplies the liquefied gas of the storage tank to the fuel tank. The boil-off gas return pipeline transfers the boil-off gas generated in the fuel tank to the fuel loading ship when the fuel is loaded via the fuel loading pipeline. The reliquefaction device reliquefies the boil-off gas of the storage tank and returns it to adjust the internal pressure of the storage tank. The reliquefaction device reduces the internal pressure of the storage tank to below the set pressure before fuel loading, and maintains the internal pressure of the storage tank to be lower than the internal pressure of the fuel tank during fuel loading. In addition, the reliquefaction device reliquefies the boil-off gas transferred via the boil-off gas return pipeline during fuel loading and returns it to the storage tank, thereby maintaining the internal pressure of the storage tank to be lower than the internal pressure of the fuel tank.

[0004] Prior art literature

[0005] Patent Document 1: Japanese Patent Application No. 2021-517878 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, before liquefied gas is supplied from the storage tank of the fuel loading ship to the fuel tank of the gas propelled ship, during the navigation of the gas propelled ship, the pressure of the boil-off gas in the fuel tank is sometimes higher than the allowable pressure of the storage tank. In this case, it is impossible to return to the storage tank via the boil-off gas return line when the fuel is loaded as in the structure described in Patent Document 1. Therefore, it is necessary to treat a part of the boil-off gas in the fuel tank by burning it, and after the pressure in the fuel tank is reduced to below the allowable pressure of the storage tank, fuel is supplied. Therefore, the burned boil-off gas is wasted, and it is desired to suppress unnecessary consumption of liquefied gas and perform more efficient operation.

[0008] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a floating body for a silo and a method for supplying liquefied gas that can suppress unnecessary consumption of liquefied gas and perform more efficient operation.

[0009] Means for solving problems

[0010] In order to solve the above-mentioned problems, the floating body for silo disclosed in the present invention comprises: a floating body, a silo tank, a liquefied gas supply pipeline, a fuel loading pump, a gas return pipeline and a bottom receiving pipeline. The silo tank is arranged on the floating body. The silo tank can accommodate liquefied gas. One end of the liquefied gas supply pipeline is arranged in the silo tank. The liquefied gas supply pipeline extends to the outside of the fuel tank. The other end of the liquefied gas supply pipeline can be connected to the fuel tank of another ship. The fuel loading pump is arranged in the silo tank. The fuel loading pump can pressurize the liquefied gas in the silo tank from one end of the liquefied gas supply pipeline to the other end. One end of the gas return pipeline can be connected to the gas pressure delivery pipeline of the fuel tank outside the silo tank. The other end of the gas return pipeline extends into the silo tank. The gas return pipeline sends the evaporated gas in the fuel tank that is pressurized from the gas pressure delivery pipeline into the gas phase in the silo tank. One end of the bottom receiving pipeline can be connected to the gas pressure delivery pipeline outside the silo tank. The bottom receiving pipeline extends into the silo tank. The other end of the bottom receiving pipeline reaches the bottom of the fuel storage tank.

[0011] The floating body for bunker disclosed in the present invention comprises: a floating body, a bunker tank, a liquefied gas supply pipeline, a fuel loading pump, a gas return pipeline and a liquefied gas discharge portion. The bunker tank is provided on the floating body. The bunker tank can accommodate liquefied gas. One end of the liquefied gas supply pipeline is arranged in the bunker tank. The liquefied gas supply pipeline extends to the outside of the fuel tank. The other end of the liquefied gas supply pipeline can be connected to the fuel tank of another ship. The fuel loading pump is provided in the bunker tank. The fuel loading pump can pressurize the liquefied gas in the bunker tank from one end of the liquefied gas supply pipeline to the other end. One end of the gas return pipeline can be connected to the gas pressure delivery pipeline of the fuel tank outside the bunker tank. The other end of the gas return pipeline extends into the bunker tank. The gas return pipeline delivers the evaporated gas in the fuel tank that is pressurized from the gas pressure delivery pipeline into the gas phase in the bunker tank. The liquefied gas discharge unit sucks the liquefied gas from the bottom of the silo tank and discharges it into the gas phase in the silo tank.

[0012] The liquefied gas supply method disclosed in the present invention is a method for supplying liquefied gas from a silo floating body to another ship. The silo floating body includes a floating body and a silo tank. The silo tank is provided on the floating body. The silo tank is capable of containing liquefied gas. The other ship uses the liquefied gas as fuel. The other ship includes a fuel tank capable of containing the liquefied gas. The liquefied gas supply method includes the following steps: a step of connecting the silo tank to the fuel tank; a step of reducing the pressure of the evaporated gas in the fuel tank; and a step of supplying the liquefied gas. In the step of connecting the silo tank and the fuel tank, the silo tank and the fuel tank are connected by a liquefied gas supply pipeline and a gas return pipeline. The liquefied gas supply pipeline is capable of supplying the liquefied gas in the silo tank from the inside of the silo tank to the inside of the fuel tank. The gas return pipeline is capable of supplying the evaporated gas in the fuel tank from the inside of the fuel tank to the silo tank. In the step of reducing the pressure of the boil-off gas in the fuel tank, the boil-off gas in the fuel tank is fed from the fuel tank into the silo tank through the gas return line. In the step of reducing the pressure of the boil-off gas in the fuel tank, the pressure of the boil-off gas in the fuel tank is reduced to a predetermined upper limit pressure or less. In the step of supplying the liquefied gas, the liquefied gas in the silo tank is supplied from the silo tank into the fuel tank through the liquefied gas supply line, and the boil-off gas in the fuel tank is fed from the fuel tank into the silo tank through the gas return line.

[0013] Effects of the Invention

[0014] According to the floating body for silos and the method for supplying liquefied gas of the present disclosure, it is possible to suppress the wasteful consumption of liquefied gas and perform more efficient operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a plan view showing a schematic structure of a silo floating body and other ships for supplying liquefied gas by the liquefied gas supply method according to the embodiment of the present disclosure.

[0016] Figure 2 It is a figure which shows the structure of the floating body for silos which concerns on 1st Embodiment of this disclosure.

[0017] Figure 3 This is a flowchart showing the flow of the liquefied gas supply method according to the embodiment of the present disclosure.

[0018] Figure 4 This is a diagram showing the state of the bunker floating body in the step of reducing the pressure of boil-off gas in the fuel tank in the liquefied gas supply method according to the first embodiment of the present disclosure.

[0019] Figure 5This is a diagram showing a state of a silo floating body in a step of supplying liquefied gas in the liquefied gas supply method according to the first embodiment of the present disclosure.

[0020] Figure 6 It is a diagram showing the structure of a floating structure for a silo according to a second embodiment of the present disclosure.

[0021] Figure 7 This is a diagram showing the state of the bunker floating body in the step of reducing the pressure of boil-off gas in the fuel tank in the liquefied gas supply method according to the second embodiment of the present disclosure.

[0022] Figure 8 This is a diagram showing a state of a silo floating body in a step of supplying liquefied gas in a liquefied gas supply method according to a second embodiment of the present disclosure.

[0023] Fig. 9 It is a diagram showing the structure of a floating structure for a silo according to a third embodiment of the present disclosure.

[0024] Fig.10 This is a diagram showing the state of the bunker floating body in the step of reducing the pressure of boil-off gas in the fuel tank in the liquefied gas supply method according to the third embodiment of the present disclosure.

[0025] Fig.11 This is a diagram showing a state of a silo floating body in a step of supplying liquefied gas in a liquefied gas supply method according to a third embodiment of the present disclosure.

[0026] Fig.12 This is a flowchart showing a procedure of controlling a control valve in a process of supplying liquefied gas in a liquefied gas supply method according to a third embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] <First Embodiment>

[0028] Below, refer to Figures 1 to 12 Next, a floating body for a silo and a method for supplying liquefied gas according to an embodiment of the present disclosure will be described.

[0029] like Figure 1 As shown, the method for supplying liquefied gas of this embodiment supplies liquefied gas for fuel from the floating body 100A for bunkers to another ship 200 that uses liquefied gas as fuel. In this embodiment, as the liquefied gas used as fuel, for example, LNG (liquefied natural gas) can be cited. As liquefied gas, in addition to LNG, LPG (liquefied petroleum gas), ammonia, hydrogen, etc. can also be cited.

[0030] (Structure of other ships)

[0031] The other ship 200 may use liquefied gas as fuel, and its type is not limited. Examples of the other ship 200 include a carrier ship for liquefied gas such as liquefied natural gas (LNG), carbon dioxide, and ammonia, a ferry, a RORO ship (roll-on / roll-off ship), a PCTC (Pure Car & Truck Carrier), a passenger ship, etc. The other ship 200 includes at least a hull 201 and a fuel tank 202 provided on the hull 201.

[0032] The hull 201 has a pair of side panels 203A and 203B constituting its outer shell, a bottom (not shown) and an upper deck 205. The side panels 203A and 203B have a pair of side panels forming the port and starboard sides, respectively. The bottom (not shown) has a bottom panel connecting these side panels 203A and 203B. Through this pair of side panels 203A and 203B and the bottom (not shown), the outer shell of the hull 201 forms a U-shape in a cross section perpendicular to the bow and stern direction FA. The hull 201 has a plurality of decks including an upper deck 205 inside. The upper deck 205 is a full deck arranged at the uppermost layer. An upper structure 207 is provided on the upper deck 205. The upper structure 207 is formed on the upper deck 205 on the stern 201b side of the hull 201. The upper structure 207 has a living area.

[0033] A prime mover (not shown) is provided in the hull 201. The prime mover is driven by the liquefied gas supplied from the fuel tank 202 as fuel. In the present embodiment, the prime movers are, for example, a main engine and an auxiliary engine. The prime mover as the main engine exerts a propulsion force for the other ship 200 to sail. The prime mover as the auxiliary engine generates power used in the other ship 200. In the present embodiment, the prime mover as the auxiliary engine is, for example, a generator engine for driving a generator (not shown). As the prime mover, for example, a steam turbine, a gas turbine, a reciprocating engine, etc. can be used.

[0034] The fuel tank 202 stores liquefied gas that serves as fuel for a prime mover (not shown). The fuel tank 202 is provided in the hull 201. In the present embodiment, the fuel tank 202 is provided in the hull 201. The fuel tank 202 may be provided, for example, on the upper deck 205. In the present embodiment, the fuel tank 202 may be, for example, cylindrical and extending in the horizontal direction. In addition, the fuel tank 202 is not limited to a cylindrical shape, and may be spherical or the like.

[0035] like Figure 2 As shown, a liquefied gas receiving line 211 and a gas pressure delivery line 212 are connected to the fuel tank 202 .

[0036] The liquefied gas receiving line 211 receives the liquefied gas L as the fuel supplied from the silo floating body 100A and delivers it to the fuel tank 202. One end 211a of the liquefied gas receiving line 211 can be connected to the liquefied gas supply line 110 of the silo floating body 100A described in detail later. The liquefied gas receiving line 211 extends into the fuel tank 202. The other end 211b of the liquefied gas receiving line 211 is arranged in the fuel tank 202. The liquefied gas receiving line 211 is provided with an on-off valve 211v for opening and closing its flow path.

[0037] The gas pressure delivery line 212 pressure-delivers the liquefied gas evaporated in the fuel tank 202, i.e., boil-off gas G, to the bunker floating body 100A. The fuel tank 202 stores a liquid liquefied gas L and boil-off gas G generated by the evaporation of the liquefied gas L. The liquefied gas L is stored at the lower part of the fuel tank 202. The boil-off gas G is stored at the upper part of the liquefied gas L in the fuel tank 202. One end 212a of the gas pressure delivery line 212 is arranged at the top of the fuel tank 202. The gas pressure delivery line 212 extends to the outside of the fuel tank 202. The other end 212b of the gas pressure delivery line 212 can be connected to the gas return line 120 of the bunker floating body 100A described in detail later. The gas pressure delivery line 212 is provided with an on-off valve 212v for opening and closing its flow path.

[0038] (Structure of floating body for silo)

[0039] like Figure 1 As shown, the bunker floating body 100A supplies liquefied gas to the fuel tank 202 of another ship 200. In this embodiment, the bunker floating body 100A is, for example, a fuel loading ship. The bunker floating body 100A is not limited to a fuel loading ship, but may be a floating body that cannot sail on its own.

[0040] The bunker floating body 100A in the present embodiment includes a floating body main body 101 as a hull and a bunker tank 102 provided on the floating body main body 101 .

[0041] The floating body 101 as a hull has a pair of side panels 103A and 103B constituting its outer shell, a bottom (not shown) and an upper deck 105. The side panels 103A and 103B have a pair of side panels forming the port and starboard sides, respectively. The bottom (not shown) has a bottom panel connecting these side panels 103A and 103B. Through this pair of side panels 103A and 103B and the bottom (not shown), the outer shell of the floating body 101 forms a U-shape in a cross section perpendicular to the bow and stern direction FA. The floating body 101 has a multi-layer deck including an upper deck 105 inside. The upper deck 105 is a full deck arranged at the uppermost layer. An upper structure 107 is provided on the upper deck 105. The upper structure 107 is formed on the upper deck 105 on the stern 101b side of the floating body 101.

[0042] The silo tank 102 can contain liquefied gas for supplying to another ship 200. The silo tank 102 is provided in the floating body 101. In the present embodiment, the silo tank 102 is provided in the floating body 101. The silo tank 102 may also be provided on the upper deck 105, for example. In addition, in the present embodiment, the silo tank 102 is, for example, cylindrical and extends in the horizontal direction. In addition, the silo tank 102 is not limited to a cylindrical shape, and may also be a spherical shape, etc.

[0043] like Figure 2 As shown, the silo tank 102 is connected to a liquefied gas supply pipeline 110 , a gas return pipeline 120 , and a bottom receiving pipeline 140A.

[0044] The liquefied gas supply line 110 supplies the liquefied gas L in the silo tank 102 to the other ship 200. One end 110a of the liquefied gas supply line 110 is arranged in the silo tank 102. One end 110a of the liquefied gas supply line 110 is arranged at the bottom of the silo tank 102. Here, the bottom refers to a position in the liquid phase in the silo tank 102 that is close to the lowest position in the silo tank 102, and for example, it can be cited as a position lower than the center in the vertical direction of the silo tank 102 or a position lower than 1 / 4 from the bottom when the dimension of the silo tank 102 in the vertical direction is set to 1.

[0045] The liquefied gas supply line 110 extends to the outside of the silo tank 102. The other end 110b of the liquefied gas supply line 110 can be connected to one end 211a of the liquefied gas receiving line 211 of the fuel tank 202 of another ship 200, in other words, it can be detached. An on-off valve 110v is provided on the other end 110b side of the liquefied gas supply line 110 to open and close the flow path. An on-off valve 110g is provided on the one end 110a side of the liquefied gas supply line 110 to open and close the flow path.

[0046] In addition, a fuel loading pump 115 is provided at one end 110a of the liquefied gas supply line 110. The fuel loading pump 115 is provided in the silo tank 102. The fuel loading pump 115 sucks the liquefied gas L in the silo tank 102. The fuel loading pump 115 can pressure-feed the sucked liquefied gas L from one end 110a of the liquefied gas supply line 110 to the other end 110b.

[0047] In the liquefied gas supply line 110 , a charging pipe (first pipe) 111 and a discharge pipe 112 are connected between an on-off valve 110 g at one end 110 a and an on-off valve 110 v at the other end 110 b .

[0048] The charging pipe 111 is used when charging the liquefied gas L from the outside of the onshore facility or the like into the silo tank 102, and extends from the outside to the inside of the silo tank 102. The lower end (the other end) 111a of the charging pipe 111 is arranged at the bottom of the silo tank 102. The charging pipe 111 is provided with an on-off valve 111v for opening and closing the flow path.

[0049] The lower end 112a of the discharge pipe 112 is disposed in the gas phase at the upper portion of the silo tank 102. The discharge pipe 112 includes an on-off valve 112v for opening and closing the flow path. The discharge pipe 112 constitutes a part of the liquefied gas discharge unit 160.

[0050] The liquefied gas discharge unit 160 is composed of a portion 110p on the one end 110a side of the liquefied gas supply line 110, a fuel loading pump 115 as a suction pump, and a discharge pipe 112. The portion 110p on the one end 110a side of the liquefied gas supply line 110 is a portion of the liquefied gas supply line 110 from the one end 110a to the position where the discharge pipe 112 is connected to the liquefied gas supply line 110. The liquefied gas discharge unit 160 operates the fuel loading pump 115 in a state where the one end 110a side of the liquefied gas supply line 110 is connected to the discharge pipe 112 by opening the on-off valve 110g and the on-off valve 112v. Thus, the liquefied gas L at the bottom of the silo tank 102 is sucked from the one end 110a of the liquefied gas supply line 110. The sucked liquefied gas L is discharged from the lower end 112a of the discharge pipe 112 into the boil-off gas G in the gas phase in the silo tank 102. The discharged liquefied gas L comes into contact with the boil-off gas G, so that the boil-off gas G is cooled.

[0051] The gas return line 120 returns the evaporated gas G in the fuel tank 202 to the silo tank 102. One end 120a of the gas return line 120 is detachable from the other end 212b of the gas pressure feed line 212 outside the silo tank 102. The gas return line 120 extends into the silo tank 102. The other end 120b of the gas return line 120 is arranged in the upper gas phase in the silo tank 102. The gas return line 120 sends the evaporated gas G in the fuel tank 202 pressure-fed from the gas pressure feed line 212 to the upper gas phase in the silo tank 102. An on-off valve 120v for opening and closing the flow path is provided on the side of one end 120a of the gas return line 120. An on-off valve 120g for opening and closing the flow path is provided on the side of the other end 120b of the gas return line 120.

[0052] The bottom receiving line 140A delivers the boil-off gas G in the fuel tank 202 returned from the fuel tank 202 through the gas return line 120 to the bottom of the silo tank 102. The bottom receiving line 140A includes at least a connecting pipe 150 and a switching valve 150v. The bottom receiving line 140A in this embodiment is composed of the connecting pipe 150, the switching valve 150v, a portion 110m between the connecting pipe 150 and the charging pipe in the liquefied gas supply line 110, and the charging pipe 111. Here, the bottom refers to a position in the liquid phase in the silo tank 102 that is close to the lowest position in the silo tank 102 as described above, and for example, a position below the center of the silo tank 102 in the vertical direction or a position below 1 / 4 from the bottom when the vertical dimension of the silo tank 102 is set to 1.

[0053] The connecting pipe 150 can connect the gas return line 120 and the charging pipe 111. One end of the connecting pipe 150 is connected to the gas return line 120 between the on-off valve 120v and the on-off valve 120g. The other end of the connecting pipe 150 is connected to the liquefied gas supply line 110 between the on-off valve 110v on the other end 110b side and the on-off valve 111v of the charging pipe 111. In addition, the other end of the connecting pipe 150 may be connected to the charging pipe 111 between the on-off valve 111v of the charging pipe 111 and the lower end 111a of the charging pipe 111.

[0054] The switching valve 150v opens and closes the flow path of the connecting pipe 150. When the switching valve 150v and the on-off valve 111v are opened, the gas return line 120 and the loading pipe 111 are connected via a portion 110m of the liquefied gas supply line 110. That is, the switching valve 150v turns on and off the delivery of the boil-off gas G from the gas return line 120 to the loading pipe 111. The bottom receiving line 140A feeds the boil-off gas G from the gas return line 120 to the loading pipe 111 via the connecting pipe 150 by opening the switching valve 150v and the on-off valve 111v. The boil-off gas G fed into the loading pipe 111 is discharged from the lower end 111a of the loading pipe 111 into the liquefied gas L in the silo tank 102. The discharged boil-off gas G dissolves in the liquefied gas L and condenses. When the other end of the connection pipe 150 is connected to the charging pipe 111 between the on-off valve 111 v of the charging pipe 111 and the lower end 111 a of the charging pipe 111 , it is not necessary to open the on-off valve 111 v .

[0055] (Steps of the method for supplying liquefied gas)

[0056] Next, a method of supplying the liquefied gas L from the above-mentioned bunker floating body 100A to the other ship 200 will be described.

[0057] like Figure 3 As shown, the method for supplying the liquefied gas L in this embodiment includes a step S11 of connecting the silo tank 102 and the fuel tank 202 , a step S12 of reducing the pressure of the boil-off gas G in the fuel tank 202 , and a step S13 of supplying the liquefied gas L.

[0058] In the step S11 of connecting the silo tank 102 to the fuel tank 202, Figure 2 As shown, the silo tank 102 and the fuel tank 202 are connected via the liquefied gas supply line 110 and the gas return line 120. The liquefied gas supply line 110 has its other end 110b connected to one end 211a of the liquefied gas receiving line 211. The gas return line 120 has its one end 120a connected to the other end 212b of the gas pressure delivery line 212. At this time, the on-off valves 110v, 110g, 111v, 112v, 120v, 120g, 211v, 212v and the switching valve 150v may all be closed.

[0059] Here, in the state immediately before step S11 , the pressure and temperature of the boil-off gas G in the fuel tank 202 are greatly increased compared to the pressure and temperature of the gas phase in the silo tank 102 due to heat input from outside the fuel tank 202 during navigation of the other ship 200 .

[0060] After step S11 is completed, the process proceeds to step S12 of reducing the pressure of the boil-off gas G in the fuel tank 202. In step S12, the boil-off gas G in the fuel tank 202 is fed from the fuel tank 202 into the silo tank 102 through the gas return line 120. Figure 4 As shown, only the on-off valves 111v, 120v, 212v and the switching valve 150v are opened. Then, the boil-off gas G in the fuel tank 202 flows from the gas phase of the fuel tank 202 into the liquefied gas L at the bottom of the silo tank 102. At the bottom of the silo tank 102, the temperature of the liquefied gas L is particularly low due to the temperature distribution of the liquefied gas L in the silo tank 102. The boil-off gas G flowing into the liquefied gas L is condensed by contact with the liquefied gas L. In this way, by sending the boil-off gas G into the silo tank 102, the pressure of the boil-off gas G in the fuel tank 202 decreases, and the temperature of the boil-off gas G also decreases. On the other hand, in the silo tank 102, the boil-off gas G dissolves in the liquefied gas L, so that the pressure of the liquefied gas L increases, and the temperature of the liquefied gas L also increases. This step S12 continues until the pressure of the boil-off gas G in the fuel tank 202 decreases to a predetermined upper limit pressure (threshold value) or less. For example, step S12 may be continued until the pressure and temperature of the boil-off gas G in the fuel tank 202 and the pressure and temperature of the liquefied gas L in the silo tank 102 are substantially in equilibrium.

[0061] After step S12 is completed, the process proceeds to step S13 of supplying liquefied gas L. In step S13, Figure 5 As shown, only the on-off valves 111v, 112v and the switching valve 150v are closed, and the other on-off valves 110v, 110g, 120v, 120g, 211v, and 212v are opened. In this state, the fuel loading pump 115 is operated. Then, the liquefied gas L in the silo tank 102 is sucked from the one end 110a of the liquefied gas supply line 110. The sucked liquefied gas L is supplied from the silo tank 102 to the fuel tank 202 through the liquefied gas supply line 110. In addition, by supplying the liquefied gas L to the fuel tank 202, the boil-off gas G in the fuel tank 202 is squeezed out of the fuel tank 202. The squeezed boil-off gas G flows into the gas pressure delivery line 212 from the one end 212a, and is sent into the silo tank 102 through the gas return line 120. At this time, in step S12, since the pressure of the boil-off gas G in the fuel tank 202 has been reduced, it is possible to suppress the pressure of the silo tank 102 from excessively rising and exceeding the allowable pressure due to the boil-off gas G being fed into the silo tank 102. After the predetermined amount of liquefied gas L is fed from the silo tank 102 into the fuel tank 202, step S13 is terminated.

[0062] In addition, during the execution of step S13, for example, when the pressure in the silo tank 102 increases, the on-off valve 112v may be opened, and the liquefied gas L at the bottom of the silo tank 102 may be sucked by the liquefied gas discharge unit 160, and discharged from the lower end 112a of the discharge pipe 112 into the gas phase boil-off gas G in the silo tank 102. The liquefied gas discharge unit 160 sucks the liquefied gas L at the bottom of the silo tank 102 from one end 110a of the liquefied gas supply line 110, and discharges the sucked liquefied gas L from the lower end 112a of the discharge pipe 112 into the gas phase boil-off gas G in the silo tank 102. The discharged liquefied gas L contacts the boil-off gas G, and the boil-off gas G is cooled, thereby reducing the pressure in the silo tank 102.

[0063] (Effect)

[0064] The bunker floating body 100A of the above-mentioned embodiment includes a bunker tank 102, a liquefied gas supply line 110, a fuel loading pump 115, and a gas return line 120. In such a bunker floating body 100A, when the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202 of the other ship 200, the bunker tank 102 and the fuel tank 202 are connected by the liquefied gas supply line 110 and the gas return line 120. The liquefied gas L in the bunker tank 102 is pressure-fed from one end 110a to the other end 110b of the liquefied gas supply line 110 by the fuel loading pump 115, thereby the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202. When the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202, the boil-off gas G in the fuel tank 202 is squeezed out. The pushed out boil-off gas G is pressure-sent from the gas pressure-sending line 212 of the fuel tank 202 to the silo tank 102 through the gas return line 120 .

[0065] Furthermore, the boil-off gas G in the fuel tank 202 can be fed to the bottom of the fuel tank line through the bottom receiving line 140A connected to the gas pressure feeding line 212 of the fuel tank 202 outside the silo tank 102. Thus, when the pressure in the fuel tank 202 is higher than the pressure in the silo tank 102, the boil-off gas G in the fuel tank 202 can be fed to the bottom of the silo tank 102 from the gas phase of the fuel tank 202. By feeding the boil-off gas G from the fuel tank 202 into the silo tank 102, the pressure in the fuel tank 202 can be reduced. The boil-off gas G condenses in the liquefied gas L at the bottom of the silo tank 102. In addition, the boil-off gas G is fed from the fuel tank 202 into the silo tank 102, so that the pressure in the silo tank 102 increases. In this way, in a state where the pressure in the fuel tank 202 is reduced, the liquefied gas L in the silo tank 102 can be supplied to the fuel tank 202 through the liquefied gas supply line 110. Therefore, it is not necessary to perform a process such as burning the boil-off gas G in the fuel tank 202 outside the fuel tank 202, and it is possible to suppress unnecessary consumption of the liquefied gas L. As a result, it is possible to suppress unnecessary consumption of the liquefied gas L and perform more efficient operation.

[0066] In addition, in a state where the pressure of the gas phase in the fuel tank 202 is higher than the pressure of the gas phase in the silo tank 102, the boil-off gas G in the fuel tank 202 is received from the gas phase of the fuel tank 202 to the bottom of the silo tank 102 through the bottom receiving line 140A. In this way, by sending the boil-off gas G from the fuel tank 202 to the silo tank 102, the pressure in the fuel tank 202 can be reduced. In addition, by sending the boil-off gas G from the fuel tank 202 to the silo tank 102, the pressure in the silo tank 102 increases, and the differential pressure between the fuel tank 202 and the silo tank 102 becomes smaller. In this state, by supplying the liquefied gas L from the silo tank 102 to the fuel tank 202, the supply of the liquefied gas L can be smoothly performed.

[0067] In addition, the bottom receiving line 140A includes a connecting pipe 150 and a switching valve 150v for connecting the gas return line 120 and the charging pipe 111 of the liquefied gas supply line 110. When the boil-off gas G in the fuel tank 202 is received from the gas phase of the fuel tank 202 to the bottom of the silo tank 102 through the bottom receiving line 140A, the switching valve 150v is operated to connect the gas return line 120 to the charging pipe 111. The boil-off gas G in the fuel tank 202 is fed to the bottom of the silo tank 102 from the gas pressure feeding line 212 via the gas return line 120 and the connecting pipe 150 through the charging pipe 111. In this way, by using the charging pipe 111 provided in the liquefied gas supply line 110, it is not necessary to provide a dedicated pipe for feeding the boil-off gas G in the fuel tank 202 to the bottom of the silo tank 102, and the cost can be reduced.

[0068] In the method S10 for supplying the liquefied gas L of the above-described embodiment, in the step S12 of reducing the pressure of the boil-off gas G in the fuel tank 202, the boil-off gas G in the fuel tank 202 is fed into the silo tank 102 through the gas return line 120, and the pressure of the boil-off gas G in the fuel tank 202 is reduced to or below a predetermined upper limit pressure. Then, in the step S13 of supplying the liquefied gas L, the liquefied gas L in the silo tank 102 is fed into the fuel tank 202 through the liquefied gas supply line 110, and the boil-off gas G in the fuel tank 202 is fed into the silo tank 102 through the gas return line 120. Therefore, unnecessary consumption of the liquefied gas L can be suppressed without performing a process of burning the boil-off gas G in the fuel tank 202 outside the fuel tank 202. As a result, unnecessary consumption of the liquefied gas L can be suppressed, and more efficient operation can be performed.

[0069] In the step S12 of reducing the pressure of the boil-off gas G in the fuel tank 202, the boil-off gas G in the fuel tank 202 is sent to the bottom of the silo tank 102, and the boil-off gas G is condensed in the liquefied gas L at the bottom of the silo tank 102. As a result, it is possible to suppress an excessive increase in the pressure in the silo tank 102, and to reduce the pressure in the fuel tank 202 to a predetermined upper limit pressure or less. Therefore, it is not necessary to perform a process of burning the boil-off gas G in the fuel tank 202 outside the fuel tank 202, and it is possible to suppress unnecessary consumption of the liquefied gas L.

[0070] <Second Embodiment>

[0071] Next, a second embodiment of the silo floating body and the liquefied gas supply method disclosed in the present invention will be described. In the second embodiment described below, only a part of the structure of the silo floating body is different from that of the first embodiment, so the second embodiment is referred to as Figure 1 , Figure 3, the same parts as those in the first embodiment are described with the same reference numerals, and repeated descriptions are omitted.

[0072] like Figure 6 As shown, the silo floating structure 100B of the second embodiment includes a bottom receiving line 140B as described below, instead of the connecting pipe 150 and the switching valve 150v as the bottom receiving line 140A in the first embodiment.

[0073] The bottom receiving line 140B includes at least a bottom extension line 170 as a second line. The bottom receiving line 140B of the present embodiment includes a bottom extension line 170 and an on-off valve 170v. The bottom extension line 170 branches from the gas return line 120 and extends to the bottom inside the silo tank 102. The bottom extension line 170 branches from the gas return line 120 between the on-off valve 120v on the one end 120a side and the on-off valve 120v on the other end 120b side in the gas return line 120. The on-off valve 170v opens and closes the flow path of the bottom extension line 170. When the on-off valve 170v is opened, the bottom receiving line 140B sends the boil-off gas G in the fuel tank 202 returned from the fuel tank 202 through the gas return line 120 to the bottom inside the silo tank 102.

[0074] (Steps of the method for supplying liquefied gas)

[0075] Next, a method of supplying the liquefied gas L from the above-mentioned bunker floating body 100B to the other ship 200 will be described.

[0076] like Figure 3 As shown, the method for supplying the liquefied gas L in this embodiment includes a step S21 of connecting the silo tank 102 and the fuel tank 202 , a step S22 of reducing the pressure of the boil-off gas G in the fuel tank 202 , and a step S23 of supplying the liquefied gas L.

[0077] In the step S21 of connecting the silo tank 102 to the fuel tank 202, as shown in FIG. Figure 6 As shown, the silo tank 102 is connected to the fuel tank 202 by using the liquefied gas supply line 110 and the gas return line 120. The liquefied gas supply line 110 has its other end 110b connected to one end 211a of the liquefied gas receiving line 211. The gas return line 120 has its one end 120a connected to the other end 212b of the gas pressure delivery line 212. At this time, the on-off valves 110v, 110g, 111v, 112v, 120v, 120g, 211v, 212v and the switching valve 150v may all be closed.

[0078] Here, in the state immediately before step S21 , the pressure and temperature of the boil-off gas G in the fuel tank 202 are greatly increased compared to the pressure and temperature of the gas phase in the silo tank 102 due to heat input from outside the fuel tank 202 during navigation of the other ship 200 .

[0079] After step S21 is completed, the process proceeds to step S22 of reducing the pressure of the boil-off gas G in the fuel tank 202. In step S22, the boil-off gas G in the fuel tank 202 is fed from the fuel tank 202 to the silo tank 102 via the gas return line 120. Figure 7 As shown, only the on-off valves 170v, 120v, and 212v are opened. Then, the boil-off gas G in the fuel tank 202 flows from the gas phase of the fuel tank 202 into the liquefied gas L at the bottom of the silo tank 102 through the bottom extension pipe 170 of the bottom receiving line 140B. At the bottom of the silo tank 102, the temperature of the liquefied gas L is particularly low due to the temperature distribution of the liquefied gas L in the silo tank 102. The boil-off gas G flowing into the liquefied gas L is condensed by contact with the liquefied gas L. In this way, by sending the boil-off gas G into the silo tank 102, the pressure of the boil-off gas G in the fuel tank 202 decreases, and the temperature of the boil-off gas G also decreases. On the other hand, in the silo tank 102, the boil-off gas G is dissolved in the liquefied gas L, and the boil-off gas G can be received while suppressing the pressure increase of the liquefied gas L. This step S22 is continued until the pressure of the boil-off gas G in the fuel tank 202 decreases to a predetermined upper limit pressure (threshold value) or less. For example, step S22 may be continued until the pressure and temperature of the boil-off gas G in the fuel tank 202 and the pressure and temperature of the liquefied gas L in the silo tank 102 are substantially in equilibrium.

[0080] After step S22 is completed, the process proceeds to step S23 of supplying liquefied gas L. In step S23, Figure 8As shown, only the on-off valves 170v, 111v, and 112v are closed, and the other on-off valves 110v, 110g, 120v, 120g, 211v, and 212v are opened. In this state, the fuel loading pump 115 is operated. Then, the liquefied gas L in the silo tank 102 is sucked from the one end 110a of the liquefied gas supply line 110. The sucked liquefied gas L is supplied from the silo tank 102 to the fuel tank 202 through the liquefied gas supply line 110. In addition, by supplying the liquefied gas L to the fuel tank 202, the boil-off gas G in the fuel tank 202 is squeezed out of the fuel tank 202. The squeezed boil-off gas G flows into the gas pressure delivery line 212 from the one end 212a, and is sent to the fuel pump 115 through the gas return line 120. At this time, in step S22, since the pressure of the boil-off gas G in the fuel tank 202 has been reduced, it is possible to suppress the pressure of the silo tank 102 from excessively rising and exceeding the allowable pressure due to the boil-off gas G being fed into the silo tank 102. After the predetermined amount of liquefied gas L is fed from the silo tank 102 into the fuel tank 202, step S23 is terminated.

[0081] In addition, during the execution of step S23, for example, when the pressure in the silo tank 102 increases, the on-off valve 112v may be opened, and the liquefied gas L at the bottom of the silo tank 102 may be sucked by the liquefied gas discharge unit 160, and discharged from the lower end 112a of the discharge pipe 112 into the gas phase boil-off gas G in the silo tank 102. The liquefied gas discharge unit 160 sucks the liquefied gas L at the bottom of the silo tank 102 from one end 110a of the liquefied gas supply line 110, and discharges the sucked liquefied gas L from the lower end 112a of the discharge pipe 112 into the gas phase boil-off gas G in the silo tank 102. The discharged liquefied gas L contacts the boil-off gas G, and the boil-off gas G is cooled, thereby reducing the pressure in the silo tank 102.

[0082] (Effect)

[0083] The bunker floating body 100B of the above-mentioned embodiment includes a bunker tank 102, a liquefied gas supply line 110, a fuel loading pump 115, and a gas return line 120. In such a bunker floating body 100B, when the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202 of the other ship 200, the bunker tank 102 and the fuel tank 202 are connected by the liquefied gas supply line 110 and the gas return line 120. The liquefied gas L in the bunker tank 102 is pressure-fed from one end 110a to the other end 110b of the liquefied gas supply line 110 by the fuel loading pump 115, and thereby the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202. When the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202, the boil-off gas G in the fuel tank 202 is squeezed out. The pushed out boil-off gas G is pressure-sent from the gas pressure-sending line 212 of the fuel tank 202 to the silo tank 102 through the gas return line 120 .

[0084] In addition, the boil-off gas G in the fuel tank 202 can be sent to the bottom of the silo tank 102 through the bottom receiving line 140B connected to the gas pressure feeding line 212 of the fuel tank 202 outside the silo tank 102. Thus, when the pressure in the fuel tank 202 is higher than the pressure in the silo tank 102, the boil-off gas G in the fuel tank 202 can be sent to the bottom of the silo tank 102 from the gas phase of the fuel tank 202. By sending the boil-off gas G from the fuel tank 202 to the silo tank 102, the pressure in the fuel tank 202 can be reduced. The boil-off gas G condenses in the liquefied gas L at the bottom of the silo tank 102. In this way, in a state where the pressure in the fuel tank 202 is reduced, the liquefied gas L in the silo tank 102 can be supplied to the fuel tank 202 through the liquefied gas supply line 110. Therefore, it is not necessary to perform a process of burning the boil-off gas G in the fuel tank 202 outside the fuel tank 202, and unnecessary consumption of the liquefied gas L can be suppressed. As a result, unnecessary consumption of the liquefied gas L can be suppressed, and more efficient operation can be performed.

[0085] In addition, in a state where the pressure of the gas phase in the fuel tank 202 is higher than the pressure of the gas phase in the silo tank 102, the boil-off gas G in the fuel tank 202 is received from the gas phase of the fuel tank 202 to the bottom of the silo tank 102 through the bottom receiving line 140B. In this way, by sending the boil-off gas G from the fuel tank 202 to the silo tank 102, the pressure in the fuel tank 202 can be reduced. In addition, by sending the boil-off gas G from the fuel tank 202 to the silo tank 102, the pressure in the silo tank 102 increases, and the differential pressure between the fuel tank 202 and the silo tank 102 becomes smaller. In this state, by supplying the liquefied gas L from the silo tank 102 to the fuel tank 202, the supply of the liquefied gas L can be smoothly performed.

[0086] In addition, the bottom receiving line 140B includes a bottom extension pipe 170 branched from the gas return line 120. When the boil-off gas G in the fuel tank 202 is received from the gas phase of the fuel tank 202 to the bottom of the silo tank 102 through the bottom receiving line 140B, the boil-off gas G in the fuel tank 202 can be sent from the gas pressure feeding line 212 to the bottom of the silo tank 102 via the gas return line 120 and the bottom extension pipe 170. In this way, the bottom receiving line 140B includes the bottom extension pipe 170 branched from the gas return line 120. In the bottom receiving line 140B, a dedicated bottom extension pipe 170 is provided to send the boil-off gas G in the fuel tank 202 from the gas phase of the fuel tank 202 to the bottom of the silo tank 102, so that the design freedom of the bottom extension pipe 170 is improved. For example, by making the bottom extension pipe 170 thinner than the charging pipe 111 , the heat exchange efficiency between the liquefied gas L in the silo tank 102 and the boil-off gas G in the bottom extension pipe 170 can be improved.

[0087] In the method S20 for supplying the liquefied gas L of the above-described embodiment, in the step S22 of reducing the pressure of the boil-off gas G in the fuel tank 202, the boil-off gas G in the fuel tank 202 is fed into the silo tank 102 through the gas return line 120, and the pressure of the boil-off gas G in the fuel tank 202 is reduced to or below a predetermined upper limit pressure. Then, in the step S23 of supplying the liquefied gas L, the liquefied gas L in the silo tank 102 is fed into the fuel tank 202 through the liquefied gas supply line 110, and the boil-off gas G in the fuel tank 202 is fed into the silo tank 102 through the gas return line 120. Therefore, unnecessary consumption of the liquefied gas L can be suppressed without performing a process of burning the boil-off gas G in the fuel tank 202 outside the fuel tank 202. As a result, unnecessary consumption of the liquefied gas L can be suppressed, and more efficient operation can be performed.

[0088] In the step S22 of reducing the pressure of the boil-off gas G in the fuel tank 202, the boil-off gas G in the fuel tank 202 is sent to the bottom of the silo tank 102, and the boil-off gas G is condensed in the liquefied gas L at the bottom of the silo tank 102. As a result, the pressure in the fuel tank 202 can be reduced to a predetermined upper limit pressure (threshold value) or less. Therefore, it is not necessary to perform a process of burning the boil-off gas G in the fuel tank 202 outside the fuel tank 202, and unnecessary consumption of the liquefied gas L can be suppressed.

[0089] <Third Embodiment>

[0090] Next, a third embodiment of the silo floating body and the liquefied gas supply method of the present disclosure will be described. In the third embodiment described below, only a part of the structure of the silo floating body is different from the first and second embodiments, so the third embodiment is referred to as Figure 1 , Figure 3 , the same parts as those in the first embodiment are described with the same reference numerals, and repeated descriptions are omitted.

[0091] like Fig. 9 As shown, a silo floating body 100C of this embodiment includes a control valve 180 and a controller 190 as described below, instead of the bottom receiving lines 140A and 140B in the first and second embodiments.

[0092] The floating body 100C for a silo in the present embodiment includes a liquefied gas discharge unit 160 , a control valve 180 , and a controller 190 .

[0093] The liquefied gas discharge unit 160 is composed of a portion 110p on the one end 110a side of the liquefied gas supply line 110, a fuel loading pump 115 as a suction pump, and a discharge pipe 112. The liquefied gas discharge unit 160 opens the on-off valve 110g and the on-off valve 112v, and operates the fuel loading pump 115 in a state where the one end 110a side of the liquefied gas supply line 110 is connected to the discharge pipe 112. As a result, the liquefied gas L at the bottom of the silo tank 102 is sucked from the one end 110a of the liquefied gas supply line 110. The sucked liquefied gas L is discharged from the lower end 112a of the discharge pipe 112 into the boil-off gas G in the gas phase in the silo tank 102. The discharged liquefied gas L contacts the boil-off gas G, and the boil-off gas G is cooled.

[0094] The control valve 180 adjusts the delivery of the gas-phase boil-off gas G sent into the silo tank 102 through the gas return line 120 . The control valve 180 is provided in a bypass line 181 that bypasses the on-off valve 120 g provided in the gas return line 120 .

[0095] The controller 190 controls the control valve 180 so that the pressure of the gas phase in the silo tank 102 is maintained below the allowable pressure of the silo tank 102. The controller 190 periodically receives the detection value of the pressure in the silo tank 102 from the pressure sensor 192 that detects the pressure in the silo tank 102. The controller 190 adjusts the opening and closing of the control valve 180 or the opening degree of the control valve 180 based on the received pressure value of the silo tank 102. The controller 190 controls the operation of the control valve 180 so that the pressure value of the silo tank 102 is maintained below the allowable pressure of the silo tank 102.

[0096] (Steps of the method for supplying liquefied gas)

[0097] Next, a method of supplying the liquefied gas L from the above-mentioned bunker floating body 100C to the other ship 200 will be described.

[0098] like Figure 3As shown, the method for supplying the liquefied gas L in this embodiment includes a step S31 of connecting the silo tank 102 and the fuel tank 202 , a step S32 of reducing the pressure of the boil-off gas G in the fuel tank 202 , and a step S33 of supplying the liquefied gas L.

[0099] In the step S31 of connecting the silo tank 102 to the fuel tank 202, Fig. 9 As shown, the silo tank 102 is connected to the fuel tank 202 by using the liquefied gas supply line 110 and the gas return line 120. The liquefied gas supply line 110 has its other end 110b connected to one end 211a of the liquefied gas receiving line 211. The gas return line 120 has its one end 120a connected to the other end 212b of the gas pressure delivery line 212. At this time, it is preferred that the on-off valves 110v, 110g, 111v, 112v, 120v, 120g, 211v, 212v and the control valve 180 are all closed.

[0100] Here, in the state immediately before step S31 , the pressure and temperature of the boil-off gas G in the fuel tank 202 are greatly increased compared to the pressure and temperature of the gas phase in the silo tank 102 due to heat input from outside the fuel tank 202 during navigation of the other ship 200 .

[0101] After step S31 is completed, the process proceeds to step S32 of reducing the pressure of the boil-off gas G in the fuel tank 202. In step S32, the boil-off gas G in the fuel tank 202 is fed from the fuel tank 202 into the silo tank 102 through the gas return line 120. Fig.10 As shown, only the on-off valves 120v, 120g, and 212v are opened. Then, the boil-off gas G in the fuel tank 202 flows from the gas phase of the fuel tank 202 through the gas return line 120 into the gas phase in the upper part of the silo tank 102. As a result, the pressure in the fuel tank 202 drops.

[0102] On the other hand, when the boil-off gas G is fed into the gas phase in the silo tank 102, the pressure of the gas phase in the silo tank 102 increases. The increase in the pressure of the gas phase pressurizes the liquid phase (liquefied gas L) in the silo tank 102, and the pressure of the liquefied gas L increases, and the liquefied gas L becomes a supercooled state.

[0103] After step S32 is completed, the process proceeds to step S33 of supplying liquefied gas L. In step S33, Fig.12As shown, only the on-off valves 111v and 120g are closed, and the other on-off valves 110v, 110g, 112v, 120v, 211v, 212v and the control valve 180 are opened. In this state, the fuel loading pump 115 is operated. Then, the liquefied gas L in the silo tank 102 is sucked from the one end 110a of the liquefied gas supply line 110. The sucked liquefied gas L is supplied from the silo tank 102 to the fuel tank 202 through the liquefied gas supply line 110. In addition, by supplying the liquefied gas L to the fuel tank 202, the boil-off gas G in the fuel tank 202 is squeezed out of the fuel tank 202. The squeezed boil-off gas G flows into the gas pressure delivery line 212 from the one end 212a, and is sent into the silo tank 102 through the gas return line 120.

[0104] In step S33, the liquefied gas discharge unit 160 discharges a portion of the liquefied gas L sucked from the bottom of the silo tank 102 into the gas phase in the silo tank 102. At the bottom of the silo tank 102, the liquefied gas L in the silo tank 102 is in a supercooled state. In this way, by sucking the liquefied gas L in the supercooled state and discharging it into the gas phase in the silo tank 102, the boil-off gas G in the silo tank 102 is condensed and reliquefied. In addition, since the temperature of the boil-off gas G in the gas phase in the silo tank 102 decreases, the pressure increase in the silo tank 102 can be suppressed. As a result, the boil-off gas G sent from the fuel tank 202 to the silo tank 102 can be well received.

[0105] Furthermore, in step S33, the controller 190 periodically receives the detected value of the pressure in the silo tank 102 from the pressure sensor 192 that detects the pressure in the silo tank 102. The controller 190 controls the operation of the control valve 180 based on the received pressure value of the silo tank 102 so as to maintain the pressure value of the silo tank 102 below the allowable pressure of the silo tank 102. Specifically, for example, Fig.12As shown, the controller 190 obtains the detection value of the pressure in the silo tank 102 at predetermined time intervals (step S1). Next, the controller 190 confirms whether the detection value of the pressure in the silo tank 102 obtained in step S1 exceeds the allowable pressure of the silo tank 102 (step S2). In step S2, when the detection value of the pressure in the silo tank 102 exceeds the allowable pressure of the silo tank 102, the controller 190 closes the control valve 180 (step S3). As a result, the supply of the evaporated gas G from the fuel tank 202 to the silo tank 102 is stopped. In addition, in this step S2, the opening of the control valve 180 can also be adjusted in the closing direction. As a result, the supply amount of the evaporated gas G from the fuel tank 202 to the silo tank 102 decreases. On the other hand, in step S2, when the detection value of the pressure in the silo tank 102 does not exceed the allowable pressure of the silo tank 102, the controller 190 maintains the opening of the control valve 180 (step S4). By repeating such a series of steps at predetermined time intervals, the controller 190 maintains the pressure of the gas phase in the silo tank 102 at or below the allowable pressure of the silo tank 102 .

[0106] In this way, in step S33 , the boil-off gas G in the silo tank 102 is suppressed from excessively increasing in pressure, and the boil-off gas G in the fuel tank 202 is fed into the silo tank 102 , thereby reducing the pressure of the boil-off gas G in the fuel tank 202 .

[0107] After a predetermined amount of liquefied gas L is supplied from the silo tank 102 to the fuel tank 202 , step S33 is terminated.

[0108] (Effect)

[0109] The bunker floating body 100C of the above-mentioned embodiment includes a bunker tank 102, a liquefied gas supply line 110, a fuel loading pump 115, and a gas return line 120. In such a bunker floating body 100C, when the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202 of the other ship 200, the bunker tank 102 and the fuel tank 202 are connected by the liquefied gas supply line 110 and the gas return line 120. The liquefied gas L in the bunker tank 102 is pressure-fed from one end 110a to the other end 110b of the liquefied gas supply line 110 by the fuel loading pump 115, thereby the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202. When the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202, the boil-off gas G in the fuel tank 202 is squeezed out. The pushed out boil-off gas G is pressure-sent from the gas pressure-sending line 212 of the fuel tank 202 to the silo tank 102 through the gas return line 120 .

[0110] In addition, the liquefied gas discharge unit 160 sucks the liquefied gas L from the bottom of the silo tank 102 and discharges it to the gas phase in the silo tank 102, thereby lowering the temperature of the boil-off gas G in the silo tank 102 and promoting liquefaction. As a result, the pressure of the boil-off gas G in the silo tank 102 can be suppressed. Therefore, when the liquefied gas L is supplied from the silo tank 102 to the fuel tank 202 of the other ship 200, the pressure increase of the silo tank 102 can be suppressed and the boil-off gas G squeezed out from the fuel tank 202 can be received as the liquefied gas L is supplied from the silo tank 102 to the fuel tank 202. As a result, unnecessary consumption of the liquefied gas L can be suppressed, and more efficient operation can be performed.

[0111] In addition, the control valve 180 for adjusting the delivery of the evaporated gas G sent into the gas phase in the silo tank 102 through the gas return pipeline 120 is controlled by the controller 190, thereby maintaining the pressure of the gas phase in the silo tank 102 below the allowable pressure of the silo tank 102 while the evaporated gas G in the fuel tank 202 is sent into the silo tank 102.

[0112] In the method S30 for supplying the liquefied gas L of the above-described embodiment, the boil-off gas G in the fuel tank 202 is fed into the silo tank 102 through the gas return line 120, and the pressure of the boil-off gas G in the fuel tank 202 is reduced to or below a predetermined upper limit pressure (threshold value). Thus, in the step S33 of supplying the liquefied gas L, the liquefied gas L in the silo tank 102 can be fed into the fuel tank 202 through the liquefied gas supply line 110, and the boil-off gas G in the fuel tank 202 can be smoothly fed into the silo tank 102 through the gas return line 120. Therefore, unnecessary consumption of the liquefied gas L can be suppressed without performing a process of burning the boil-off gas G in the fuel tank 202 outside the fuel tank 202. As a result, unnecessary consumption of the liquefied gas L can be suppressed, and more efficient operation can be performed.

[0113] (Other embodiments)

[0114] As mentioned above, although the embodiment of this disclosure is described in detail with reference to drawings, the specific structure is not limited to this embodiment, and design changes etc. which do not deviate from the gist of this disclosure are also included.

[0115] In the third embodiment, the controller 190 controls the control valve 180, and the boil-off gas G in the fuel tank 202 is fed into the silo tank 102 while the pressure of the gas phase in the silo tank 102 is maintained below the allowable pressure of the silo tank 102. Such a structure can be combined with the structures shown in the first and second embodiments and applied in the same manner.

[0116] In addition, the steps of the above-mentioned liquefied gas supply method S10, S20, and S30 may be modified appropriately.

[0117] <Notes>

[0118] The silo floating bodies 100A, 100B, 100C and the supply methods S10, S20, and S30 of the liquefied gas L described in the respective embodiments can be understood, for example, as follows.

[0119] (1) The first embodiment of the bunker floating body 100A, 100B comprises: a floating body 101; a bunker tank 102, which is provided in the floating body 101 and can accommodate liquefied gas L; a liquefied gas supply line 110, one end 110a of which is arranged in the bunker tank 102 and extends outside the bunker tank 102, and the other end 110b of which can be connected to the fuel tank 202 of another ship 200; a fuel loading pump 115, which is provided in the bunker tank 102 and can pressurize the liquefied gas L in the bunker tank 102 from the one end 110a of the liquefied gas supply line 110 to the other end 110b; a gas The return pipeline 120 has one end 120a that can be connected to the gas pressure delivery pipeline 212 of the above-mentioned fuel tank 202 outside the above-mentioned silo tank 102, and the other end 120b extends into the above-mentioned silo tank 102, and delivers the evaporated gas G in the above-mentioned fuel tank 202 pressurized from the above-mentioned gas pressure delivery pipeline 212 into the gas phase in the above-mentioned silo tank 102; and the bottom receiving pipeline 140A, 140B, one end of which can be connected to the gas pressure delivery pipeline 212 of the above-mentioned fuel tank 202 outside the above-mentioned silo tank 102 and extend into the above-mentioned silo tank 102, and the other end 111a reaches the bottom of the above-mentioned silo tank 102.

[0120] The bunker floating bodies 100A and 100B are provided with a bunker tank 102, a liquefied gas supply line 110, a fuel loading pump 115, and a gas return line 120. In such a bunker floating body 100A, when the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202 of the other ship 200, the bunker tank 102 and the fuel tank 202 are connected by the liquefied gas supply line 110 and the gas return line 120. The liquefied gas L in the bunker tank 102 is pressure-fed from one end 110a to the other end 110b of the liquefied gas supply line 110 by the fuel loading pump 115, thereby the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202. When the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202, the boil-off gas G in the fuel tank 202 is squeezed out. The pushed out boil-off gas G is pressure-sent from the gas pressure-sending line 212 of the fuel tank 202 to the silo tank 102 through the gas return line 120 .

[0121] In addition, the boil-off gas G in the fuel tank 202 can be fed to the bottom of the silo tank 102 through the bottom receiving lines 140A and 140B connected to the gas pressure feeding line 212 of the fuel tank 202 outside the silo tank 102. Thus, when the pressure in the fuel tank 202 is higher than the pressure in the silo tank 102, the boil-off gas G in the fuel tank 202 can be fed to the bottom of the silo tank 102 from the gas phase of the fuel tank 202. By feeding the boil-off gas G from the fuel tank 202 into the silo tank 102, the pressure in the fuel tank 202 can be reduced. The boil-off gas G condenses in the liquefied gas L at the bottom of the silo tank 102. In this way, in a state where the pressure in the fuel tank 202 is reduced, the liquefied gas L in the silo tank 102 can be supplied to the fuel tank 202 through the liquefied gas supply line 110. Therefore, unnecessary consumption of the liquefied gas L can be suppressed without performing a process such as burning the boil-off gas G in the fuel tank 202 outside the fuel tank 202. As a result, unnecessary consumption of the liquefied gas L can be suppressed, and more efficient operation can be performed.

[0122] (2) The second type of silo float 100A, 100B is based on the silo float 100A, 100B of (1), and the bottom receiving pipeline 140A, 140B receives the evaporated gas G in the fuel tank 202 from the gas phase of the fuel tank 202 to the bottom of the silo tank 102 when the pressure of the gas phase in the fuel tank 202 is higher than the pressure of the gas phase in the silo tank 102.

[0123] Thus, in a state where the pressure of the gas phase in the fuel tank 202 is higher than the pressure of the gas phase in the silo tank 102, the boil-off gas G in the fuel tank 202 is received from the gas phase of the fuel tank 202 to the bottom of the silo tank 102 through the bottom receiving lines 140A and 140B. In this way, by sending the boil-off gas G from the fuel tank 202 to the silo tank 102, the pressure in the fuel tank 202 can be reduced. In addition, the boil-off gas G is sent from the fuel tank 202 to the silo tank 102, thereby increasing the pressure of the gas phase in the silo tank 102, and reducing the differential pressure between the fuel tank 202 and the silo tank 102.

[0124] (3) The third type of silo float 100A is based on the silo float 100A of (1) or (2), and the above-mentioned liquefied gas supply pipeline 110 has a first pipe 111 with one end 110a arranged at the bottom of the above-mentioned silo tank 102, and the above-mentioned bottom receiving pipeline 140A has: a connecting pipe 150 capable of connecting the above-mentioned gas return pipeline 120 with the above-mentioned first pipe 111; and a switching valve 150v to connect and disconnect the delivery of the above-mentioned evaporated gas G from the above-mentioned gas return pipeline 120 to the above-mentioned first pipe 111.

[0125] Thus, the bottom receiving line 140A includes a connecting pipe 150 and a switching valve 150v for connecting the gas return line 120 and the first pipe 111 of the liquefied gas supply line 110. When the boil-off gas G in the fuel tank 202 is received from the gas phase of the fuel tank 202 to the bottom of the silo tank 102 through the bottom receiving line 140A, the switching valve 150v is operated to connect the gas return line 120 to the first pipe 111. The boil-off gas G in the fuel tank 202 is sent to the bottom of the silo tank 102 from the gas pressure feeding line 212 via the gas return line 120 and the connecting pipe 150 through the first pipe 111. In this way, by using the first pipe 111 of the liquefied gas supply line 110, it is not necessary to provide a dedicated pipe for sending the boil-off gas G in the fuel tank 202 to the bottom of the silo tank 102, and cost reduction can be achieved.

[0126] (4) A fourth embodiment of the silo floating body 100B is the silo floating body 100B according to any one of (1) to (3), wherein the bottom receiving line 140B includes a second pipe 170 branching from the gas return line 120 and extending to the bottom of the silo tank 102 .

[0127] Thus, the bottom receiving line 140B includes the second pipe 170 branching from the gas return line 120. When the boil-off gas G in the fuel tank 202 is received from the gas phase of the fuel tank 202 to the bottom of the silo tank 102 through the bottom receiving line 140B, the boil-off gas G in the fuel tank 202 can be sent from the gas pressure feeding line 212 to the bottom of the silo tank 102 via the gas return line 120 and the second pipe 170. Thus, the bottom receiving line 140B includes the second pipe 170 branching from the gas return line 120. By providing the second pipe 170 to send the boil-off gas G in the fuel tank 202 from the gas phase of the fuel tank 202 to the bottom of the silo tank 102 through the bottom receiving line 140B, the degree of freedom in designing the second pipe 170 is improved.

[0128] (5) The fifth embodiment of the silo floating body 100A, 100B is based on any one of the silo floating bodies 100A, 100B in (1) to (4), and further includes a liquefied gas discharge unit 160 that sucks the liquefied gas L from the bottom of the silo tank 102 and discharges it into the gas phase in the silo tank 102.

[0129] Thus, the liquefied gas discharge unit 160 sucks the liquefied gas L from the bottom of the silo tank 102 and discharges it into the gas phase in the silo tank 102, thereby lowering the temperature of the boil-off gas G in the silo tank 102 to promote liquefaction. Thus, the pressure of the boil-off gas G in the silo tank 102 can be suppressed.

[0130] (6) The sixth embodiment of the silo float 100A, 100B is based on the silo float 100A of (5), and includes: a control valve 180 for adjusting the delivery of the evaporating gas G sent into the gas phase in the silo tank 102 through the gas return pipeline 120; and a controller 190 for controlling the control valve 180 so that the pressure of the gas phase in the silo tank 102 is maintained below the allowable pressure of the silo tank 102.

[0131] Thus, the control valve 180 for adjusting the delivery of the evaporated gas G delivered to the gas phase in the silo tank 102 through the gas return pipeline 120 is controlled by the controller 190, thereby enabling the evaporated gas G in the fuel tank 202 to be delivered to the silo tank 102 while maintaining the pressure of the gas phase in the silo tank 102 below the allowable pressure of the silo tank 102.

[0132] (7) The seventh embodiment of the bunker floating body 100C comprises: a floating body 101; a bunker tank 102, which is provided in the floating body 101 and can accommodate liquefied gas L; a liquefied gas supply line 110, one end 110a of which is arranged in the bunker tank 102 and extends to the outside of the bunker tank 102, and the other end 110b of which can be connected to a fuel tank 202 of another ship 200; and a fuel loading pump 115, which is provided in the bunker tank 102 and can pressurize the liquefied gas L from the one end 110a of the liquefied gas supply line 110 to the other end 110b. The liquefied gas L in the silo tank 102; a gas return pipeline 120, one end 120a of which can be connected to the gas pressure delivery pipeline 212 of the fuel tank 202 outside the silo tank 102, and the other end 120b extends into the silo tank 102, and delivers the evaporated gas G in the fuel tank 202 pressurized from the gas pressure delivery pipeline 212 into the gas phase in the silo tank 102; and a liquefied gas discharge part 160, which sucks the liquefied gas L from the bottom of the silo tank 102 and discharges it into the gas phase in the silo tank 102.

[0133] Thus, the bunker floating body 100C includes the bunker tank 102, the liquefied gas supply line 110, the fuel loading pump 115, and the gas return line 120. In such a bunker floating body 100A, when the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202 of the other ship 200, the bunker tank 102 and the fuel tank 202 are connected by the liquefied gas supply line 110 and the gas return line 120. The liquefied gas L in the bunker tank 102 is pressure-fed from one end to the other end of the liquefied gas supply line 110 by the fuel loading pump 115, thereby the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202. When the liquefied gas L is supplied from the bunker tank 102 to the fuel tank 202, the boil-off gas G in the fuel tank 202 is squeezed out. The pushed out boil-off gas G is pressure-sent from the gas pressure-sending line 212 of the fuel tank 202 to the silo tank 102 through the gas return line 120 .

[0134] In addition, the liquefied gas discharge unit 160 sucks the liquefied gas L from the bottom of the silo tank 102 and discharges it to the gas phase in the silo tank 102, thereby lowering the temperature of the boil-off gas G in the silo tank 102 and promoting liquefaction. As a result, the pressure of the boil-off gas G in the silo tank 102 can be suppressed. Therefore, when the liquefied gas L is supplied from the silo tank 102 to the fuel tank 202 of the other ship 200, the pressure increase of the silo tank 102 can be suppressed and the boil-off gas G squeezed out from the fuel tank 202 can be received as the liquefied gas L is supplied from the silo tank 102 to the fuel tank 202. As a result, unnecessary consumption of the liquefied gas L can be suppressed, and more efficient operation can be performed.

[0135] (8) The eighth embodiment of the silo float 100C is based on the silo float 100C of (7), and comprises: a control valve 180 for adjusting the delivery of the evaporating gas G sent into the gas phase in the silo tank 102 through the gas return pipeline 120; and a controller 190 for controlling the control valve 180 so that the pressure of the gas phase in the silo tank 102 is maintained below the allowable pressure of the silo tank 102.

[0136] Thus, the control valve 180 for adjusting the delivery of the evaporated gas G delivered to the gas phase in the silo tank 102 through the gas return pipeline 120 is controlled by the controller 190, thereby enabling the evaporated gas G in the fuel tank 202 to be delivered to the silo tank 102 while maintaining the pressure of the gas phase in the silo tank 102 below the allowable pressure of the silo tank 102.

[0137] (9) The ninth embodiment of the method S10, S20, S30 for supplying liquefied gas L is a method S10, S20, S30 for supplying liquefied gas L from a silo floating body 100A to another ship 200, wherein the silo floating body 100A includes a floating body main body 101 and a silo tank 102 provided on the floating body main body 101 and capable of accommodating liquefied gas L, and the other ship 200 uses the liquefied gas L as fuel and includes a fuel tank 202 capable of accommodating the liquefied gas L. The method S10, S20, S30 for supplying liquefied gas L includes the following steps: steps S11, S21, S31 of connecting the silo tank 102 and the fuel tank 202 via a liquefied gas supply line 110 and a gas return line 120, wherein the liquefied gas supply line 110 is capable of supplying the silo tank 102 from the inside of the silo tank 102 to the inside of the fuel tank 202. 02, the gas return pipeline 120 can supply the evaporated gas G in the fuel tank 202 from the fuel tank 202 to the silo tank 102; the evaporated gas G in the fuel tank 202 is sent from the fuel tank 202 to the silo tank 102 through the gas return pipeline 120, so that the pressure of the evaporated gas G in the fuel tank 202 drops to below a predetermined upper limit pressure, steps S12, S22, S32; and the liquefied gas L in the silo tank 102 is supplied from the silo tank 102 to the fuel tank 202 through the liquefied gas supply pipeline 110, and the evaporated gas G in the fuel tank 202 is sent from the fuel tank 202 to the silo tank 102 through the gas return pipeline 120. Steps S13, S23, S33.

[0138] In the supply method S10, S20, and S30 of the liquefied gas L, in the steps S12, S22, and S32 of reducing the pressure of the boil-off gas G in the fuel tank 202, the boil-off gas G in the fuel tank 202 is fed into the silo tank 102 through the gas return line 120, and the pressure of the boil-off gas G in the fuel tank 202 is reduced to or below a predetermined upper limit pressure. Then, in the steps S13, S23, and S33 of feeding the boil-off gas G in the fuel tank 202 into the silo tank 102, the liquefied gas L in the silo tank 102 is fed into the fuel tank 202 through the liquefied gas supply line 110, and the boil-off gas G in the fuel tank 202 is fed into the silo tank 102 through the gas return line 120. Therefore, unnecessary consumption of the liquefied gas L can be suppressed without performing a process of burning the boil-off gas G in the fuel tank 202 outside the fuel tank 202. As a result, unnecessary consumption of the liquefied gas L can be suppressed, and more efficient operation can be performed.

[0139] (10) The tenth method S10, S20 for supplying liquefied gas L is based on the method S10, S20 for supplying liquefied gas L in (9). In the steps S12, S22 for reducing the pressure of the evaporated gas G in the fuel tank 202 to below a predetermined upper limit pressure, the evaporated gas G in the fuel tank 202 is received from the gas phase of the fuel tank 202 to the bottom of the silo tank 102, thereby reducing the pressure in the fuel tank 202 to below the allowable pressure of the silo tank 102.

[0140] Thus, by sending the boil-off gas G in the fuel tank 202 to the bottom of the silo tank 102, the boil-off gas G is condensed in the liquefied gas L at the bottom of the silo tank 102. As a result, the pressure in the fuel tank 202 can be reduced to a predetermined upper limit pressure or less. Therefore, without performing a process such as burning the boil-off gas G in the fuel tank 202 outside the fuel tank 202, it is possible to suppress unnecessary consumption of the liquefied gas L.

[0141] (11) The liquefied gas L supply method S10, S20, S30 of the eleventh scheme is based on the liquefied gas L supply method S10, S20, S30 of (9), and the liquefied gas L is sucked from the bottom of the above-mentioned silo tank 102 and discharged to the gas phase in the above-mentioned silo tank 102, thereby reducing the pressure of the evaporated gas G in the above-mentioned fuel tank 202 to below a predetermined upper limit pressure.

[0142] Thus, by sucking the liquefied gas L from the bottom of the silo tank 102 and discharging it to the gas phase in the silo tank 102, the temperature of the boil-off gas G in the silo tank 102 that forms the gas phase can be lowered, and liquefaction can be promoted. As a result, the pressure of the boil-off gas G in the silo tank 102 can be suppressed. Therefore, the pressure of the boil-off gas G in the silo tank 102 can be suppressed from excessively increasing, and the boil-off gas G of the fuel tank 202 can be sent to the silo tank 102, so that the pressure of the boil-off gas G in the fuel tank 202 can be lowered.

[0143] (12) The liquefied gas L supply method S30 of the twelfth scheme is based on the liquefied gas L supply method S30 of (11). In the step S32 of reducing the pressure of the evaporated gas G in the above-mentioned fuel tank 202 to below a predetermined upper limit pressure, the delivery of the above-mentioned evaporated gas G delivered to the gas phase in the above-mentioned silo tank 102 through the above-mentioned gas return pipeline 120 is adjusted in such a manner that the pressure of the gas phase in the above-mentioned silo tank 102 is maintained below the allowable pressure of the above-mentioned silo tank 102.

[0144] This can suppress an excessive increase in the pressure of the boil-off gas G in the silo tank 102 , and can also send the boil-off gas G in the fuel tank 202 into the silo tank 102 to reduce the pressure of the boil-off gas G in the fuel tank 202 .

[0145] Possibility of Industrial Application

[0146] According to the floating body for silos and the method for supplying liquefied gas of the present disclosure, it is possible to suppress the meaningless consumption of liquefied gas and perform more efficient operation.

[0147] Description of Reference Numerals

[0148] 100A to 100C…Floating body for bunker 101…Floating body body 101b…Stern 102…Bunker tank 103A, 103B…Side 105…Upper deck 107…Upper structure 110…Liquid gas supply line 110a…One end 110b…Other end 110g…On-off valve 110p…Part 110m…Part 110v…On-off valve 111…Intake pipe (first pipe) 111a…Lower end (other end) 111v…On-off valve 112…Discharge pipe 112a…Lower end 112v…On-off valve 115…Fuel loading pump (suction pump) 120…Gas return line 120a…One end 120b…Other end 120g…On-off valve 120v…On-off Valves 140A, 140B…Bottom receiving pipeline 150…Connecting piping 150v…Switching valve 160…Liquid gas discharge portion 170…Bottom extension piping (second piping) 170v…Opening and closing valve 180…Control valve 181…Bypass pipeline 190…Controller 192…Pressure sensor 200…Other ship 201…Hull 201b…Fuel tank 203A, 203B…Side 205…Upper deck 207…Upper structure 211…Liquid gas receiving pipeline 205a…One end 211b…The other end 211v…Opening and closing valve 212…Gas pressure delivery pipeline 212a…One end 212b…The other end 212v…Opening and closing valve FA…Bow and stern direction G…Evaporated gas L…Liquid gas.

Claims

1. A floating body for a silo, comprising: floating body; A silo tank, provided on the floating body, capable of containing liquefied gas; A liquefied gas supply pipeline, one end of which is arranged in the silo tank and extends outside the silo tank, and the other end of which can be connected to the fuel tank of another ship; a fuel loading pump, disposed in the silo tank, capable of pressurizing the liquefied gas in the silo tank from one end of the liquefied gas supply pipeline to the other end; A gas return pipeline, one end of which can be connected to the gas pressure delivery pipeline of the fuel tank outside the silo tank, and the other end of which extends into the silo tank to deliver the evaporated gas in the fuel tank pressured from the gas pressure delivery pipeline into the gas phase in the silo tank; and A bottom receiving pipeline has one end that can be connected to the gas pressure delivery pipeline outside the silo tank and extend into the silo tank, and the other end reaches the bottom of the silo tank.

2. The buoy for silo according to claim 1, wherein: The bottom receiving line receives the boil-off gas in the fuel tank from the gas phase of the fuel tank to the bottom of the silo tank in a state where the pressure of the gas phase in the fuel tank is higher than the pressure of the gas phase in the silo tank.

3. The floating body for silo according to claim 1 or 2, wherein: The liquefied gas supply line has a first pipe having one end disposed at the bottom of the silo tank. The bottom receiving pipeline has: a connecting pipe capable of connecting the gas return line and the first pipe; and The switching valve turns on and off the supply of the boil-off gas from the gas return line to the first pipe.

4. The floating body for silo according to claim 1 or 2, wherein: The bottom receiving line includes a second pipe branched from the gas return line and extending to the bottom of the silo tank.

5. The floating body for silo according to claim 1 or 2, wherein: The silo floating body further includes a liquefied gas discharge unit that sucks the liquefied gas from the bottom of the silo tank and discharges the liquefied gas into a gas phase in the silo tank.

6. The floating body for silo according to claim 5, wherein: The silo floating body comprises: a control valve to regulate the delivery of the boil-off gas through the gas return line to the gas phase in the silo tank; and The controller controls the control valve so that the pressure of the gas phase in the silo tank is maintained below the allowable pressure of the silo tank.

7. A floating body for a silo, comprising: floating body; A silo tank, provided on the floating body, capable of containing liquefied gas; A liquefied gas supply pipeline, one end of which is arranged in the silo tank and extends outside the silo tank, and the other end of which can be connected to the fuel tank of another ship; a fuel loading pump, disposed in the silo tank, capable of pressurizing the liquefied gas in the silo tank from one end of the liquefied gas supply pipeline to the other end; A gas return pipeline, one end of which can be connected to the gas pressure delivery pipeline of the fuel tank outside the silo tank, and the other end of which extends into the silo tank to deliver the evaporated gas in the fuel tank pressured from the gas pressure delivery pipeline into the gas phase in the silo tank; and The liquefied gas discharge unit sucks the liquefied gas from the bottom of the silo tank and discharges it into the gas phase in the silo tank.

8. The floating body for silo according to claim 7, wherein: The silo floating body comprises: a control valve to regulate the delivery of the boil-off gas through the gas return line to the gas phase in the silo tank; and The controller controls the control valve so that the pressure of the gas phase in the silo tank is maintained below the allowable pressure of the silo tank.

9. A method for supplying liquefied gas from a silo floating body to another ship, the silo floating body comprising a floating body main body and a silo tank provided on the floating body main body and capable of accommodating liquefied gas, the other ship using the liquefied gas as fuel and comprising a fuel tank capable of accommodating the liquefied gas, The liquefied gas supply method comprises the following steps: The step of connecting the silo tank and the fuel tank via a liquefied gas supply line and a gas return line, wherein the liquefied gas supply line can supply the liquefied gas in the silo tank from the inside of the silo tank to the inside of the fuel tank, and the gas return line can supply the evaporated gas in the fuel tank from the inside of the fuel tank to the silo tank; The process of feeding the boil-off gas in the fuel tank from the fuel tank into the silo tank through the gas return line to reduce the pressure of the boil-off gas in the fuel tank to below a predetermined upper limit pressure; and The step of supplying the liquefied gas in the silo tank from the silo tank to the fuel tank through the liquefied gas supply line and sending the boil-off gas in the fuel tank from the fuel tank to the silo tank through the gas return line.

10. The method for supplying liquefied gas according to claim 9, wherein: In the step of reducing the pressure of the boil-off gas in the fuel tank to a predetermined upper limit pressure or less, By receiving the boil-off gas in the fuel tank from the gas phase of the fuel tank to the bottom of the silo tank, the pressure in the fuel tank is reduced to or lower than the allowable pressure of the fuel tank.

11. The method for supplying liquefied gas according to claim 9, wherein: The pressure of the boil-off gas in the fuel tank is reduced to a predetermined upper limit pressure or less by sucking the liquefied gas from the bottom of the silo tank and discharging it into the gas phase in the silo tank.

12. The method for supplying liquefied gas according to claim 11, wherein: In the step of reducing the pressure of the boil-off gas in the fuel tank to a predetermined upper limit pressure or less, The delivery of the boil-off gas sent to the gas phase in the silo tank through the gas return line is adjusted so that the pressure of the gas phase in the silo tank is maintained at or below the allowable pressure of the fuel tank.

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