Floating body

Abstract

To provide a floating body capable of removing an inert gas in mixed gas stored in a tank and capable of increasing calorie per a unit volume of the mixed gas.SOLUTION: A floating body comprises a floating main body, a tank installed in the floating main body, to store ammonia, and to store the mixed gas of the ammonia and of the other gas different from the ammonia as a gas phase, a compressing part to compress the mixed gas which is introduced from the inside of the tank, a separation membrane to separate the mixed gas into the ammonia and the other gas by introducing the mixed gas compressed by the compressing part, and a cooling part to cool the ammonia returned to the tank after the separation by the separation membrane.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a floating body. [Background technology]

[0002] Patent Document 1 discloses a ship that uses LNG or the like as its main fuel. In a ship that uses liquefied gas such as LNG as its main fuel, the liquefied gas vaporizes in a tank that stores the liquefied gas due to natural heat input from outside the tank, generating boil off gas (BOG). When the BOG increases in the tank, the pressure in the tank increases. As a method for treating BOG to suppress the increase in pressure in the tank, there is a method of re-liquefying compressed BOG using a refrigeration cycle of a re-liquefaction device and returning it to the tank as liquid fuel as in Patent Document 1, and a method of introducing it into a combustion device as gas fuel.

[0003] Meanwhile, in the field of ships, the introduction of ammonia, a decarbonized fuel, as fuel for combustion equipment such as main engines is being considered. When ammonia, a type of liquefied gas, is used as fuel for combustion equipment, BOG is generated even in the tanks storing the ammonia, making it necessary to treat the BOG as described above. In addition, inert gases such as seal gas used in pumps and other devices and purge gas used to replace the atmosphere in piping are mixed into the liquefied gas tanks while the ship is in operation. Therefore, the gas phase in the tanks is a mixture of this inert gas and BOG. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-204026 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the ship described in the above Patent Document 1, the BOG in the storage tank is reliquefied to produce liquefied gas, but the inert gas may not be reliquefied and may remain in a gaseous state and may be mixed in the liquefied gas and returned to the tank together. That is, the ratio of the inert gas in the mixed gas may increase. Therefore, for example, when the mixed gas stored in the tank is used as gas fuel, there is a problem that the calorific value per unit volume of the mixed gas decreases. In addition, when the ratio of the inert gas in the mixed gas increases, the reliquefaction efficiency may decrease.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a floating body that can increase the heat quantity per unit volume of mixed gas stored in a tank. [Means for solving the problem]

[0007] In order to solve the above problems, a float according to the present disclosure comprises a float body, a tank provided on the float body for storing ammonia and storing a mixed gas of ammonia and another gas different from the ammonia as a gas phase component, a compression section to which the mixed gas in the tank is introduced and compresses the mixed gas, a separation membrane into which the mixed gas compressed by the compression section is introduced and which separates the mixed gas into the ammonia and the other gas, and a cooling section for cooling the ammonia separated by the separation membrane and returned to the tank. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a float capable of increasing the heat quantity per unit volume of a mixed gas stored in a tank. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a side view of a floating body according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram showing a BOG treatment system according to the first embodiment of the present disclosure. [Diagram 3]FIG. 11 is a diagram showing a BOG treatment system according to a second embodiment of the present disclosure. [Figure 4] FIG. 13 is a diagram showing a BOG treatment system according to a third embodiment of the present disclosure. [Diagram 5] FIG. 13 is a diagram showing a BOG treatment system according to another embodiment of the present disclosure. [Figure 6] FIG. 13 is a diagram showing a BOG treatment system according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a floating body according to each embodiment of the present disclosure will be described with reference to the drawings.

[0011] [First embodiment] (Floating structure) The floating body in this embodiment is a ship that uses ammonia as fuel. The type of the floating body is not limited to a specific one. Examples of the type of the floating body include a liquefied gas carrier, a ferry, a RO-RO ship, a car carrier, and a passenger ship.

[0012] As shown in Figures 1 and 2, the float 1 includes a float body 10, an upper structure 20, a combustion device 30, a tank 40, a fuel supply system 50, a gas supply system 60, a purge system 70, an ammonia recovery system 80, and a BOG treatment system 120.

[0013] (Floating body) As shown in Fig. 1, the floating body 10 is a hull having side panels 11A, 11B, a ship bottom 12, and an upper deck 13. The side panels 11A, 11B have a pair of side panel shells that form the left and right side panels 11A, 11B and the side panels 11A, 11B, respectively. The ship bottom 12 has a double-bottom ship bottom 12 shell plate that connects the side panels 11A, 11B. The upper deck 13 is provided across the pair of side panel shell plates.

[0014] The outer hull of the floating body 10 is formed into a box shape in a cross section perpendicular to the bow-stern direction Fa by the ship sides 11A, 11B, the ship bottom 12, and the upper deck 13. The bow-stern direction Fa in this embodiment is the direction extending from the stern 15 to the bow 14 of the floating body 10.

[0015] (superstructure) The superstructure 20 is a structure provided to extend upward in the vertical direction Dv from the upper deck 13. Inside the superstructure 20, for example, accommodation areas, a bridge, etc. are provided.

[0016] (Combustion equipment) The combustion device 30 is a device that generates thermal energy by burning fuel. The combustion device 30 is provided, for example, in a compartment such as an engine room (not shown) provided inside the floating body main body 10. Examples of the combustion device 30 include a main engine for propelling the floating body 1, a generator for supplying electricity to the ship, and a boiler for generating steam as a working fluid. The combustion device 30 in this embodiment is a main engine that uses ammonia as fuel.

[0017] (tank) The tank 40 stores therein ammonia as fuel for the combustion device 30. The tank 40 in this embodiment is provided on the upper deck 13 closer to the stern 15 than the superstructure 20 in the bow-stern direction Fa.

[0018] (Fuel supply system) The fuel supply system 50 is a system that supplies ammonia from the tank 40 to the combustion device 30. The fuel supply system 50 in this embodiment is provided inside the floating body 10, for example. As shown in FIG. 2, the fuel supply system 50 includes a supply line 51 and a return line 52.

[0019] The supply line 51 is a pipe connecting the tank 40 and the combustion device 30. Ammonia as fuel flows through the supply line 51 from the tank 40 to the combustion device 30. Therefore, ammonia is introduced from the tank 40 to the combustion device 30 through the supply line 51. The supply line 51 is provided with a pump (not shown) for pressure-feeding the ammonia from the tank 40 to the combustion device 30, a heat exchanger (not shown) for heating the ammonia in the supply line 51 guided to the combustion device 30 by the pump, and the like.

[0020] The return line 52 is a pipe connecting the combustion device 30 and the tank 40. One end of the return line 52 is connected to the combustion device 30, and the other end is connected to the tank 40. In the return line 52, ammonia that has not been completely combusted in the combustion device 30 and remains in the tank 40 flows from the combustion device 30 to the tank 40. Therefore, the ammonia sent to the tank 40 by the return line 52 is supplied again into the supply line 51 in the tank 40, and is reused for combustion in the combustion device 30.

[0021] (Gas supply system) The gas supply system 60 is a system that sends inert gas to the fuel supply system 50 and the combustion device 30 and purges ammonia present in the fuel supply system 50 and the combustion device 30. The gas supply system 60 in this embodiment is provided, for example, inside the floating body 10. The gas supply system 60 includes an inert gas supply device 61, a first purge line 62, and a first purge valve 63.

[0022] The inert gas supplying device 61 is a device that generates and pumps an inert gas for purging that is non-reactive with ammonia. Examples of the inert gas include nitrogen gas (N2). The inert gas supplying device 61 in this embodiment is provided, for example, inside the floating body 10. Hereinafter, the inert gas is referred to as another gas since it is a gas different from ammonia.

[0023] The first purge line 62 is a pipe through which the inert gas generated by the inert gas supply device 61 flows. One end of the first purge line 62 is connected to the inert gas supply device 61. The other end of the first purge line 62 is connected to the supply line 51.

[0024] The other gas pumped from the inert gas supply device 61 through the first purge line 62 flows into the supply line 51, and is then pumped through the combustion device 30 and the return line 52 in that order. As a result, the other gas pushes out (purges) the ammonia present in the supply line 51, the combustion device 30, and the return line 52.

[0025] The first purge valve 63 is an automatically operated valve provided in the first purge line 62. The first purge valve 63 is normally closed and is opened at a predetermined timing. When the first purge valve 63 is opened, other gases can flow through the first purge line 62 from the inert gas supply device 61 toward the supply line 51. The automatically operated valve shown in this embodiment includes a solenoid valve, a valve driven by an electric motor, and the like.

[0026] (Purge system) The purge system 70 is a system that guides ammonia remaining in the supply line 51, the combustion device 30, and the return line 52 to the tank 40. The purge system 70 in this embodiment is provided, for example, inside the floating body 10. The purge system 70 includes a plurality of second purge lines 71 and a plurality of second purge valves 72.

[0027] One end of each of the second purge lines 71 is connected to the supply line 51 and the return line 52. The other ends of each of the second purge lines 71 extend toward an ammonia recovery system 80 outside the fuel supply system 50. As ammonia present in the supply line 51, the combustion device 30, and the return line 52 is purged with other gases, the ammonia is pushed out of the fuel supply system 50 through the second purge line 71 together with the other gases.

[0028] In this embodiment, as an example, two second purge lines 71 connect the supply line 51 and the temporary storage section 81, and connect the return line 52 and the temporary storage section 81, respectively.

[0029] The second purge valves 72 are automatically operated valves provided one each on the second purge lines 71. The second purge valves 72 are normally closed and are opened together with the first purge valve 63. Therefore, when the first purge valve 63 and the second purge valve 72 are opened, other gases flow through the first purge line 62 and into the supply line 51, the combustion device 30, and the return line 52.

[0030] When other gases flow into these supply line 51, combustion device 30, and return line 52, the ammonia purged by the other gases flows toward the temporary storage section 81 via each second purge line 71. That is, the ammonia remaining in the supply line 51, combustion device 30, and return line 52 is replaced (purged) with the other gas.

[0031] (Ammonia recovery system) The ammonia recovery system 80 is a system that temporarily recovers the ammonia purged from the fuel supply system 50 through the purge system 70 and returns the recovered ammonia to the tank 40. The ammonia recovery system 80 in this embodiment is provided, for example, inside the floating body 10. The ammonia recovery system 80 includes a temporary storage section 81 and a recovery line 82 .

[0032] The temporary storage section 81 is a container that temporarily stores ammonia remaining in the supply line 51, the combustion device 30, and the return line 52. Ammonia in the supply line 51, the combustion device 30, and the return line 52 is introduced into the temporary storage section 81 through the second purge line 71. The temporary storage section 81 in this embodiment is provided inside the floating body 10, for example.

[0033] The recovery line 82 is a pipe for returning the vaporized ammonia in the temporary storage unit 81 to the tank 40. The recovery line 82 connects the temporary storage unit 81 and the tank 40. Therefore, the ammonia in the temporary storage unit 81 flows through the recovery line 82 toward the tank 40.

[0034] In addition, the ammonia recovery system 80 may include an oil catch tank that removes the oil stored in the temporary storage section 81 and recovers it outside the temporary storage section 81, and an oil mist separator that recovers the mist-like oil that flows through the recovery line 82 together with ammonia and other gases in the oil catch tank.

[0035] One end of a flue 110, which is a duct for guiding exhaust gas G1 generated in the combustion device 30 to the outside of the floating body 10, is connected to the combustion device 30. The other end of the flue 110 penetrates the upper deck 13 and extends upward in the vertical direction Dv outside the floating body 10. As shown in FIG. 1 , the portion of the flue 110 extending to the outside of the floating body 10 is surrounded by a hull structure 170 and a funnel 180.

[0036] (BOG treatment system) The BOG treatment system 120 is a system that treats a mixed gas of ammonia stored in the tank 40 as a gas phase component and other gases different from this ammonia. The mixed gas in this embodiment is a mixture of BOG generated by volatilization of liquefied ammonia in the tank 40 and other gases flowing in from the fuel supply system 50 and the ammonia recovery system 80. The BOG treatment system 120 in this embodiment is provided, for example, inside the floating body main body 10.

[0037] The BOG treatment system 120 includes a first treatment line 126 , a compression section 121 , a second treatment line 127 , a separation membrane 122 , a first ammonia line 130 , a cooling section 123 , and a gas line 132 .

[0038] (First processing line) The first treatment line 126 is a pipe that guides the mixed gas in the tank 40 to the compression section 121. The first treatment line 126 connects the tank 40 and the compression section 121. In the first treatment line 126, the mixed gas introduced from the tank 40 flows toward the compression section 121.

[0039] (Compression section) The compression section 121 compresses the mixed gas in the tank 40. The mixed gas is introduced into the compression section 121 via a first treatment line 126. The compression section 121 in this embodiment is provided, for example, inside the floating body main body 10. An example of the compression section 121 is a compressor used in an engine or the like different from the combustion device 30 (main engine) of this embodiment.

[0040] (Second processing line) The second treatment line 127 is a pipe that guides the mixed gas compressed by the compression unit 121 to the separation membrane 122. The second treatment line 127 connects the compression unit 121 and the separation membrane 122. In the second treatment line 127, the mixed gas compressed by the compression unit 121 flows toward the separation membrane 122.

[0041] (separation membrane) The separation membrane 122 is a device that separates the mixed gas compressed by the compression section 121 into ammonia and other gases when the mixed gas is introduced therein. The mixed gas is introduced from the compression section 121 to the separation membrane 122 via a second treatment line 127. As the separation membrane 122 in this embodiment, for example, a zeolite separation membrane can be used.

[0042] (First ammonia line) The first ammonia line 130 is a pipe that guides the ammonia separated from the mixed gas by the separation membrane 122 to the tank 40. The first ammonia line 130 connects the separation membrane 122 and the tank 40. In the first ammonia line 130, the ammonia separated by the separation membrane 122 flows toward the tank 40.

[0043] (cooling section) The cooling unit 123 is a device that cools the ammonia separated by the separation membrane 122 and returned to the tank 40. The cooling unit 123 is a heat exchanger provided midway through the first ammonia line 130. For example, cooling water is introduced into the cooling unit 123 from outside the BOG supply system. For example, seawater or fresh water produced by a water maker (not shown) or the like is used as the cooling water. The cooling section 123 cools the ammonia by exchanging heat between the cooling water and the ammonia flowing through the first ammonia line 130 toward the tank 40.

[0044] (Gas Line) The gas line 132 is a pipe for extracting the other gas separated from the mixed gas by the separation membrane 122 to the outside of the BOG treatment system 120. One end of the gas line 132 is connected to the separation membrane 122. The other end of the gas line 132 extends to the outside of the floating body main body 10. When the other gas flowing through the gas line 132 contains a small amount of ammonia, a dilution device (not shown) that reduces the concentration of ammonia by mixing the ammonia contained in the other gas with external air or the like may be provided midway through the gas line 132.

[0045] (Action and effect) According to the configuration of the floating body 1 according to the embodiment, the mixed gas stored in the tank 40 as a gas phase component is introduced to the compression section 121 and compressed, and then passes through the separation membrane 122 to become ammonia. The ammonia separated from the mixed gas is cooled in the cooling section 123 and returned to the tank 40. By repeating this action, the ratio of other gases in the gas phase component in the tank 40 can be reduced. Therefore, the heat quantity per unit volume of the mixed gas stored in the tank 40 as a gas phase component can be increased.

[0046] Moreover, according to the configuration of the floating body 1 according to the above embodiment, the ammonia remaining inside the combustion device 30, the supply line 51, and the return line 52 is introduced into the temporary storage section 81, and the ammonia vaporized in the temporary storage section 81 is returned to the tank 40 together with other gases. That is, the ammonia remaining in the combustion device 30, the supply line 51, and the return line 52 can be recovered together with other gases into the tank 40. On the other hand, since the ratio of other gases in the mixed gas in the tank 40 can be reduced, the heat quantity of the mixed gas in the tank 40 is not reduced. Therefore, the ammonia in the combustion device 30, the supply line 51, and the return line 52 can be actively recovered together with other gases.

[0047] [Second embodiment] Next, the configuration of a floating body according to a second embodiment of the present disclosure will be described with reference to the drawings. In the second embodiment, the configuration of the BOG treatment system is different from that of the BOG treatment system 120 in the first embodiment. The same parts as those in the first embodiment will be described with the same reference numerals, and duplicated descriptions will be omitted.

[0048] (BOG treatment system) As shown in FIG. 3, the BOG treatment system 120a includes a first treatment line 126, a compression section 121, a separation line 128, a separation membrane 122, a first ammonia line 130, a cooling section 123, a gas line 132, a reliquefaction line 129, a condenser 124, an expansion valve 125, and a switching section 150. The first ammonia line 130, the cooling section 123, and the gas line 132 in this embodiment have the same configurations as those in the first embodiment.

[0049] (First processing line) The first treatment line 126 is a pipe that guides the mixed gas in the tank 40 to the compression section 121. The first treatment line 126 connects the tank 40 and the first compressor 121a of the compression section 121. In the first treatment line 126, the mixed gas introduced from the tank 40 flows toward the first compressor 121a of the compression section 121.

[0050] (Compression section) The compression unit 121 compresses the mixed gas in the tank 40. The compression unit 121 of the present embodiment is a multi-stage compressor. The compression unit 121 includes a first compressor 121a, an interstage line 121d, an intercooler 121b, and a second compressor 121c.

[0051] The first compressor 121a is a compressor that compresses the mixed gas in the tank 40. The mixed gas is introduced to the first compressor 121a via a first treatment line 126. The first compressor 121a compresses the mixed gas to an intermediate pressure and then discharges it. That is, the first compressor 121a is a low-pressure side compressor in the compression section 121.

[0052] The interstage line 121d is a pipe that guides the mixed gas discharged from the first compressor 121a on the low-pressure side of the compression section 121 to the second compressor 121c. The mixed gas compressed by the first compressor 121a flows in the interstage line 121d.

[0053] The intercooler 121b is a heat exchanger that cools the mixed gas compressed by the first compressor 121a. The intercooler 121b is provided in the middle of the interstage line 121d. For example, cooling water is introduced into the intercooler 121b from outside the BOG supply system. The intercooler 121b cools the mixed gas to a predetermined temperature by exchanging heat between the cooling water and the mixed gas flowing in the interstage line 121d.

[0054] The second compressor 121c is a compressor that compresses the mixed gas cooled by the intercooler 121b. The mixed gas cooled by the intercooler 121b is introduced to the second compressor 121c through an interstage line 121d. The second compressor 121c compresses the mixed gas to a maximum pressure higher than the intermediate pressure and then discharges it.

[0055] (Separation line) The separation line 128 is a pipe that guides the mixed gas compressed by the second compressor 121c of the compression section 121 to the separation membrane 122. The separation line 128 connects the second compressor 121c of the compression section 121 and the separation membrane 122. In the separation line 128, the mixed gas compressed by the second compressor 121c of the compression section 121 flows toward the separation membrane 122.

[0056] (separation membrane) The separation membrane 122 has the same configuration as that of the first embodiment. The separation membrane 122 is a device that separates the mixed gas compressed by the second compressor 121c of the compression section 121 into ammonia and other gases when the mixed gas is introduced thereinto. The mixed gas is introduced to the separation membrane 122 from the compression section 121 via a separation line 128.

[0057] (Reliquefaction line) The reliquefaction line 129 is a pipe that guides the mixed gas compressed by the second compressor 121c of the compression section 121 to the tank 40. The reliquefaction line 129 connects the separation line 128 to the tank 40. That is, one end of the reliquefaction line 129 is connected to branch off from the separation line 128, and the other end of the separation line 128 is connected to the tank 40. In the reliquefaction line 129, the mixed gas compressed by the second compressor 121c of the compression section 121 flows toward the tank 40.

[0058] (Capacitor) The condenser 124 is a condenser that cools and condenses the mixed gas compressed by the second compressor 121c of the compression section 121. That is, the condenser 124 reliquefies the mixed gas compressed by the second compressor 121c of the compression section 121. The condenser 124 is provided midway along the reliquefaction line 129.

[0059] For example, cooling water is introduced from outside the BOG supply system into the condenser 124. The condenser 124 exchanges heat between the cooling water and the mixed gas flowing in the reliquefaction line 129, thereby cooling the mixed gas to a temperature at which the ammonia contained in the mixed gas is condensed.

[0060] (Expansion valve) The expansion valve 125 is a valve that adiabatically expands the mixed gas condensed (reliquefied) by the condenser 124 to reduce the pressure and temperature. The expansion valve 125 in this embodiment is an electronic or mechanical expansion valve, and changes the condensed ammonia sent from the condenser 124 into a gas-liquid mixed fluid. Therefore, the mixed gas that flows from the separation line 128 into the reliquefaction line 129 is reliquefied in the condenser 124, and flows into the tank 40 after being depressurized and cooled by adiabatic expansion in the expansion valve 125.

[0061] In this embodiment, the compression section 121, the condenser 124, and the expansion valve 125 constitute a reliquefaction device 140 that reliquefies the mixed gas.

[0062] (Switching section) The switching unit 150 is a device that can switch between a state in which the mixed gas compressed by the compression unit 121 is supplied to the separation membrane 122 and a state in which the mixed gas compressed by the compression unit 121 is supplied to the condenser . The switching unit 150 includes a first switching valve 128a, a second switching valve 129a, and a valve control device 150a.

[0063] The first switching valve 128a is an automatically operated valve provided in the separation line 128 on the separation membrane 122 side of the point where the separation line 128 and the reliquefaction line 129 are connected. The first switching valve 128a is in an open state during other gas separation operations and is closed at a predetermined timing. When the first switching valve 128a is in a closed state, it blocks the mixed gas flowing through the separation line 128 so that it cannot flow into the separation membrane 122.

[0064] The second switching valve 129a is an automatically operated valve provided in the reliquefaction line 129 between the point where the separation line 128 and the reliquefaction line 129 are connected and the condenser 124. The second switching valve 129a is in a closed state when the first switching valve 128a is in an open state, and is in an open state when the first switching valve 128a is in a closed state. When the second switching valve 129a is in a closed state, it shuts off the mixed gas flowing through the reliquefaction line 129 so that it cannot flow into the condenser 124.

[0065] The valve control device 150a is a device that controls the open and closed states of the first switching valve 128a and the second switching valve 129a. The valve control device 150a and the first switching valve 128a and the second switching valve 129a are connected by wire or wirelessly. The valve control device 150a transmits signals instructing the first switching valve 128a and the second switching valve 129a to be in the open and closed states, respectively. The first switching valve 128a and the second switching valve 129a are set to the open state or the closed state based on the signals transmitted from the valve control device 150a.

[0066] When the first switching valve 128a is opened and the second switching valve 129a is closed, the mixed gas compressed by the compression unit 121 can be supplied to the separation membrane 122. The mixed gas supplied to the separation membrane 122 is separated into other gases and ammonia by the separation membrane 122. The separated ammonia is cooled through the cooling unit 123 to become liquid, and then returned to the tank 40. That is, when the switching unit 150 is in a state where the mixed gas compressed by the compression unit 121 is supplied to the separation membrane 122, only the ammonia contained in the mixed gas is recovered in the tank 40. In this embodiment, this state is referred to as an ammonia recovery mode.

[0067] When the first switching valve 128a is closed and the second switching valve 129a is open, the mixed gas compressed by the compression unit 121 is capable of being supplied to the condenser 124 provided in the reliquefaction line 129. The mixed gas supplied to the condenser 124 is condensed (reliquefied) to become liquid, and then returned to the tank 40 via the expansion valve 125. That is, when the switching unit 150 is in a state in which the mixed gas compressed by the compression unit 121 is supplied to the condenser 124, the mixed gas is reliquefied. In this embodiment, this state is referred to as a reliquefaction mode.

[0068] The valve control device 150a automatically switches between the ammonia recovery mode and the re-liquefaction mode based on information input to an operation input unit (not shown) such as a control panel.

[0069] (Action and effect) According to the configuration of the floating body 1 according to the above embodiment, the switching unit 150 can switch between an ammonia recovery mode and a reliquefaction mode. When the switching unit 150 is in the ammonia recovery mode, the ratio of other gases in the mixed gas in the tank 40 decreases. For example, when the ratio of other gases in the mixed gas decreases, the switching unit 150 switches to the reliquefaction mode. As a result, the mixed gas in the tank 40 is guided to the compression unit 121 of the reliquefaction device 140 and compressed, and then condensed (reliquefied) by the condenser 124 of the reliquefaction device 140. Therefore, the mixed gas with an increased ratio of ammonia per unit volume can be reliquefied by the reliquefaction device 140, so that the reliquefaction efficiency of the reliquefaction device 140 can be improved.

[0070] Moreover, by setting the switching unit 150 to the ammonia recovery mode, the compressor of the reliquefaction device 140 can be used to compress the mixed gas to be introduced into the separation membrane 122. Therefore, it is possible to suppress the need to install additional facilities on the existing equipment of the floating body 1.

[0071] [Third embodiment] Next, the configuration of a floating body according to a third embodiment of the present disclosure will be described with reference to the drawings. In the third embodiment, the configuration of the BOG treatment system is different from that of the BOG treatment system 120a in the first and second embodiments. The same parts as those in the first and second embodiments will be described with the same reference numerals, and duplicated descriptions will be omitted.

[0072] (BOG treatment system) As shown in FIG. 4, the BOG treatment system 120b includes a first treatment line 126, a compression section 121, a separation line 128, a separation membrane 122, a reliquefaction line 129, a first ammonia line 130, a condenser 124, a gas line 132, an expansion valve 125, a second ammonia line 131, and a switching section 150. In this embodiment, the first treatment line 126, the compression section 121, the separation line 128, the separation membrane 122, and the gas line 132 have the same configurations as those in the first embodiment.

[0073] (Reliquefaction line) The reliquefaction line 129 is a pipe that guides the mixed gas compressed by the second compressor 121c of the compression section 121 to the tank 40. The reliquefaction line 129 connects the separation line 128 to the tank 40. That is, one end of the reliquefaction line 129 is connected to branch off from the separation line 128, and the other end of the separation line 128 is connected to the tank 40. In the reliquefaction line 129, the mixed gas compressed by the second compressor 121c of the compression section 121 flows toward the tank 40.

[0074] (First ammonia line) The first ammonia line 130 is a pipe that guides the ammonia separated from the mixed gas by the separation membrane 122 to the reliquefaction line 129. The first ammonia line 130 connects the separation membrane 122 and the reliquefaction line 129. In the first ammonia line 130, the ammonia separated by the separation membrane 122 flows toward the inside of the reliquefaction line 129.

[0075] (Capacitor) The condenser 124 is a heat exchanger that cools and condenses the mixed gas compressed by the second compressor 121c of the compression section 121 and the ammonia separated from the mixed gas by the separation membrane 122. That is, the condenser 124 in this embodiment also serves as the cooling section 123 described in the first and second embodiments, and reliquefies the mixed gas compressed by the second compressor 121c of the compression section 121 and the ammonia separated from the mixed gas by the separation membrane 122. The condenser 124 is provided in the reliquefaction line 129 closer to the tank 40 than the point where the reliquefaction line 129 and the first ammonia line 130 are connected.

[0076] (Expansion valve) The expansion valve 125 is a valve that adiabatically expands the mixed gas condensed (reliquefied) by the condenser 124 to reduce the pressure and temperature. The expansion valve 125 is provided in the reliquefaction line 129 on the tank 40 side of the condenser 124. The expansion valve 125 in this embodiment is an electronic or mechanical expansion valve, and changes the condensed ammonia sent from the condenser 124 into a gas-liquid mixed fluid. Therefore, the mixed gas flowing in the reliquefaction line 129 is reliquefied by the condenser 124, and flows into the tank 40 after being depressurized and cooled by adiabatic expansion in the expansion valve 125.

[0077] The fluid flowing from the condenser 124 to the reliquefaction line 129 toward the tank 40 may be a mixed gas or ammonia. Hereinafter, these will be simply referred to as fluid. In this embodiment, the compression section 121, the condenser 124, and the expansion valve 125 constitute a reliquefaction device 140 that reliquefies the mixed gas.

[0078] (Second ammonia line) The second ammonia line 131 is a pipe that guides the ammonia cooled by the condenser 124 to the tank 40. The second ammonia line 131 connects the reliquefaction line 129 between the condenser 124 and the expansion valve 125 to the tank 40. In the second ammonia line 131, the ammonia cooled by the condenser 124 flows toward the tank 40.

[0079] (Switching section) The switching unit 150 is a device that can switch between a state in which the mixed gas compressed by the compression unit 121 is supplied to the separation membrane 122 and a state in which the mixed gas compressed by the compression unit 121 is directly supplied to the condenser . The switching unit 150 includes a first switching valve 128a, a second switching valve 129a, a third switching valve 129b, a fourth switching valve 131a, and a valve control device 150b.

[0080] The first switching valve 128a is an automatically operated valve provided in the separation line 128 on the separation membrane 122 side of the point where the separation line 128 and the reliquefaction line 129 are connected. The first switching valve 128a is in an open state during other gas separation operations and is closed at a predetermined timing. When the first switching valve 128a is in a closed state, it blocks the mixed gas flowing through the separation line 128 so that it cannot flow into the separation membrane 122.

[0081] The second switching valve 129a is an automatically operated valve provided in the reliquefaction line 129 between the point where the separation line 128 and the reliquefaction line 129 are connected and the condenser 124. The second switching valve 129a is in a closed state when the first switching valve 128a is in an open state, and is in an open state when the first switching valve 128a is in a closed state. When the second switching valve 129a is in a closed state, it shuts off the mixed gas flowing through the reliquefaction line 129 so that it cannot flow into the condenser 124.

[0082] The third switching valve 129b is an automatically operated valve provided in the reliquefaction line 129 on the tank 40 side of the expansion valve 125. The third switching valve 129b is in a closed state when the first switching valve 128a is in an open state, and is in an open state when the first switching valve 128a is in a closed state. In other words, the third switching valve 129b is operated to be in the same open / closed state as the second switching valve 129a. When the third switching valve 129b is in a closed state, it blocks the fluid flowing through the reliquefaction line 129 so that it cannot flow into the tank 40.

[0083] The fourth switching valve 131a is an automatically operated valve provided in the second ammonia line 131. The fourth switching valve 131a is in an open state when the first switching valve 128a is in an open state, and is in a closed state when the first switching valve 128a is in a closed state. That is, the fourth switching valve 131a is operated to be in the same open / closed state as the first switching valve 128a. When the fourth switching valve 131a is in a closed state, it blocks the fluid flowing through the second ammonia line 131 so that it cannot flow into the tank 40.

[0084] The valve control device 150b is a device that controls and monitors the open and closed states of the first switching valve 128a, the second switching valve 129a, the third switching valve 129b, and the fourth switching valve 131a. The valve control device 150b is connected to the first switching valve 128a, the second switching valve 129a, the third switching valve 129b, and the fourth switching valve 131a by wire or wirelessly. The valve control device 150b transmits and receives signals instructing the first switching valve 128a, the second switching valve 129a, the third switching valve 129b, and the fourth switching valve 131a to be in the open or closed state. The first switching valve 128a, the second switching valve 129a, the third switching valve 129b, and the fourth switching valve 131a are in the open state or the closed state based on the signal transmitted from the valve control device 150b.

[0085] When the first switching valve 128a and the fourth switching valve 131a are opened and the second switching valve 129a and the third switching valve 129b are closed, the mixed gas compressed by the second compressor 121c of the compression unit 121 can be supplied to the separation membrane 122. The mixed gas supplied to the separation membrane 122 is separated into other gases and ammonia by the separation membrane 122. The separated ammonia is cooled through the condenser 124 as the cooling unit 123, and then flows into the second ammonia line 131 and is returned to the tank 40. That is, when the switching unit 150 is in a state where the mixed gas compressed by the compression unit 121 is supplied to the separation membrane 122, the ammonia contained in the mixed gas is recovered in the tank 40. In this embodiment, this state is called an ammonia recovery mode.

[0086] When the first switching valve 128a and the fourth switching valve 131a are closed and the second switching valve 129a and the third switching valve 129b are open, the mixed gas compressed by the second compressor 121c of the compression unit 121 can be supplied to the condenser 124 provided in the reliquefaction line 129. The mixed gas supplied to the condenser 124 is condensed (reliquefied) to become liquid, and then returned to the tank 40 via the expansion valve 125. That is, when the switching unit 150 is in a state where the mixed gas compressed by the compression unit 121 is supplied to the condenser 124, the mixed gas is reliquefied. In this embodiment, this state is referred to as a reliquefaction mode.

[0087] (Action and effect) According to the configuration of the floating body 1 according to the above embodiment, the switching unit 150 can switch between an ammonia recovery mode and a reliquefaction mode. When the switching unit 150 is in the ammonia recovery mode, the ratio of other gases in the mixed gas in the tank 40 decreases. When the ratio of other gases in the mixed gas decreases, the switching unit 150 is in the reliquefaction mode, and the mixed gas in the tank 40 is guided to the compression unit 121 of the reliquefaction device 140, compressed, and then condensed (reliquefied) by the condenser 124 of the reliquefaction device 140. Therefore, the reliquefaction device 140 reliquefies the mixed gas with an increased ratio of ammonia per unit volume, and the reliquefaction efficiency of the reliquefaction device 140 can be improved.

[0088] Furthermore, by switching the switching unit 150 to the ammonia recovery mode, the compressor of the reliquefaction device 140 is used to compress the mixed gas to be introduced into the separation membrane 122, and the ammonia separated by the separation membrane 122 is condensed (reliquefied) by the condenser 124 of the reliquefaction device 140 serving as the cooling unit 123. Therefore, additional installation of existing facilities equipped in the floating body 1 can be suppressed.

[0089] [Other embodiments] Although the embodiments of the present disclosure have been described above in detail with reference to the drawings, the specific configuration is not limited to the configuration of the embodiment, and addition, omission, substitution, and other modifications of the configuration are possible within the scope of the gist of the present disclosure. Furthermore, the present disclosure is not limited to the embodiments, but is limited only by the claims.

[0090] In addition, one end of each of the second purge lines 71 described in the above embodiment is connected to the supply line 51 and the return line 52, but this is not limited to the configuration. The number of the second purge lines 71 may be any appropriate number, and the number of the second purge lines 71 is not limited to two. For example, one end of the second purge line 71 may be connected to an appropriate location such as the combustion device 30.

[0091] In the above embodiment, the valve control devices 150a and 150b automatically switch the switching valves (first switching valve 128a, second switching valve 129a, third switching valve, and fourth switching valve) based on input information from the operation input unit, but the present invention is not limited to this configuration. For example, the switching unit 150 may not have the valve control devices 150a and 150b, and the switching valves of the switching unit 150 may be manually switched to switch between the ammonia recovery mode and the re-liquefaction mode.

[0092] In the above embodiment, when the combustion device 30 is a main engine or a boiler that uses gaseous ammonia as fuel, the gaseous ammonia is supplied to the combustion device 30 from the tank 40 via the supply line 51. In this case, the fuel supply system 50 does not need to include the return line 52.

[0093] 5, the floating body 1 described in the embodiment may further include an ammonia buffer tank 53 that is provided in the supply line 51 and to which the other end of the return line 52 is connected. The ammonia buffer tank 53 recovers, from the combustion device 30, the fuel ammonia that has returned without being supplied to the inside of the combustion device 30, i.e., that has not been used for combustion. The ammonia buffer tank 53 supplies the recovered ammonia to the supply line 51 again as ammonia to be used as fuel for the main engine.

[0094] In this case, the first treatment line 126, the reliquefaction line 129, and the first ammonia line 130 or the second ammonia line 131 in the BOG treatment systems 120, 120a, 120b may be connected to this ammonia buffer tank 53.

[0095] Also, as shown in FIG. 6, when the floating body 1 is equipped with an ammonia buffer tank 53, the first treatment line 126, the reliquefaction line 129, and the first ammonia line 130 or the second ammonia line 131 in the BOG treatment systems 120, 120a, 120b may be connected to the tank 40.

[0096] In the above embodiment, the floating body 1 is a ship fueled by ammonia, but is not limited to a ship fueled by ammonia. The floating body 1 may be fueled by liquefied gas such as LNG or LPG. The floating body 1 may be an FSRU (Floating Storage and Regasification Unit) or an FSU (Floating Storage Unit).

[0097] [Note] The float described in the embodiment can be understood, for example, as follows.

[0098] (1) A float 1 according to a first embodiment includes a float body 10, a tank 40 provided on the float body 10 for storing ammonia and storing a mixed gas of ammonia and another gas other than the ammonia as a gas phase component, a compression section 121 to which the mixed gas in the tank 40 is introduced and which compresses the mixed gas, a separation membrane 122 into which the mixed gas compressed by the compression section 121 is introduced and which separates the mixed gas into the ammonia and the other gas, and a cooling section 123 for cooling the ammonia separated by the separation membrane 122 and returned to the tank 40.

[0099] As a result, the mixed gas stored in the gas phase in tank 40 is guided to compression section 121 and compressed, and then passes through separation membrane 122 to become ammonia. The ammonia separated from the mixed gas is cooled in cooling section 123 and returned to tank 40. By repeating this action, the proportion of other gases in the gas phase in tank 40 can be reduced.

[0100] (2) The float 1 according to the second aspect is the float 1 of (1), further comprising a condenser 124 capable of condensing the mixed gas compressed by the compression section 121, and an expansion valve 125 capable of adiabatically expanding the mixed gas condensed by the condenser 124, and the compression section 121, the condenser 124, and the expansion valve 125 constitute a reliquefaction device 140 for reliquefying the mixed gas, and further comprising a switching section 150 capable of switching between an ammonia recovery mode in which the mixed gas compressed by the compression section 121 is supplied to the separation membrane 122, and a reliquefaction mode in which the mixed gas compressed by the compression section 121 is supplied to the condenser 124.

[0101] As a result, the switching unit 150 switches to the ammonia recovery mode, thereby decreasing the proportion of other gases in the mixed gas in the tank 40. When the proportion of other gases has decreased, the switching unit 150 switches to the re-liquefaction mode, and the mixed gas in the tank 40 is guided to the compression unit 121 of the re-liquefaction device 140, compressed, and then condensed by the condenser 124 of the re-liquefaction device 140. In addition, the compressor of the reliquefaction device 140 can be used to compress the mixed gas to be introduced into the separation membrane 122 .

[0102] (3) The float 1 according to a third aspect is the float 1 of (1), further comprising a condenser 124 capable of condensing the mixed gas compressed by the compression section 121, and an expansion valve 125 capable of adiabatically expanding the mixed gas condensed by the condenser 124, and the compression section 121, the condenser 124, and the expansion valve 125 constitute a reliquefaction device 140 for reliquefying the mixed gas, and the condenser 124 also serves as the cooling section 123, and comprises a switching section 150 capable of switching between a first state in which the mixed gas compressed by the compression section 121 is supplied to the separation membrane 122 and the ammonia separated by the separation membrane 122 is supplied to the condenser 124, and a second state in which the mixed gas compressed by the compression section 121 is supplied to the condenser 124 without passing through the separation membrane 122.

[0103] As a result, the switching unit 150 switches to the ammonia recovery mode, thereby decreasing the proportion of other gases in the mixed gas in the tank 40. When the proportion of other gases has decreased, the switching unit 150 switches to the re-liquefaction mode, and the mixed gas in the tank 40 is guided to the compression unit 121 of the re-liquefaction device 140, compressed, and then condensed by the condenser 124 of the re-liquefaction device 140. In addition, a compressor of the reliquefaction device 140 is used to compress the mixed gas to be introduced into the separation membrane 122 , and the ammonia separated by the separation membrane 122 is cooled by a condenser 124 of the reliquefaction device 140 as a cooling unit 123 .

[0104] (4) A float 1 according to a fourth aspect is a float 1 according to any one of (1) to (3), further comprising a supply line 51 for supplying the ammonia stored in the tank 40 to the combustion device 30 as fuel, a gas supply device capable of supplying the other gases from the tank 40 to the combustion device 30 via the supply line 51, a temporary storage section 81 into which the ammonia remaining inside the combustion device 30 and the supply line 51 is introduced together with the other gases supplied to the combustion device 30 via the supply line 51, and a recovery line 82 connecting the temporary storage section 81 to the tank 40 and returning the ammonia vaporized in the temporary storage section 81 to the tank 40 together with the other gases.

[0105] As a result, ammonia remaining inside the combustion device 30 and the supply line 51 is introduced into the temporary storage section 81, and the ammonia vaporized in the temporary storage section 81 is returned to the tank 40 together with other gases. That is, the ammonia remaining in the combustion device 30 can be recovered into the tank 40 together with the other gases. Meanwhile, since the ratio of other gases in the mixed gas in the tank 40 can be reduced, the calorific value of the mixed gas in the tank 40 does not decrease. [Explanation of symbols]

[0106] 1...float 10...float body 11A, 11B...shipside 12...bottom 13...upper deck 14...bow 15...stern 20...superstructure 30...combustion device 40...tank 50...fuel supply system 51...supply line 52...return line 53...ammonia buffer tank 60...gas supply system 61...inert gas supply device 62...first purge line 63...first purge valve 70...purge system 71...second purge line 72...second purge valve 80...ammonia recovery system 81...temporary storage section 82...recovery line 110...flue 120, 120a, 120b...BOG treatment system 121...compression section 121a...first compressor 121b...intercooler 121c...second compressor 121d...interstage line 122...separation membrane 123...cooling section 124...condenser 125...expansion valve 126...first treatment line 127...second treatment line 128...separation line 128a...first change-over valve 129...reliquefaction line 129 129a...second change-over valve 129b...third change-over valve 130...first ammonia line 131...second ammonia line 131a...fourth change-over valve 132...gas line 140...reliquefaction device 150...change-over section 150a, 150b...valve control device 170...hull structure 180...funnel Dv...vertical direction Fa...fore-aft direction G1...exhaust gas

Claims

1. A floating body; A tank provided on the floating body for storing ammonia and storing a mixed gas of ammonia and another gas different from the ammonia as a gas phase component; a compression section to which the mixed gas in the tank is introduced and which compresses the mixed gas; a separation membrane that separates the mixed gas compressed by the compression unit into the ammonia and the other gas; A cooling unit that cools the ammonia separated by the separation membrane and returned to the tank; A floating body comprising:

2. a condenser capable of condensing the mixed gas compressed in the compression section; an expansion valve capable of adiabatically expanding the mixed gas condensed by the condenser; Further comprising: a reliquefaction device that reliquefies the mixed gas is configured by the compression unit, the condenser, and the expansion valve, 2. The float according to claim 1, further comprising a switching unit that can switch between an ammonia recovery mode in which the mixed gas compressed by the compression unit is supplied to the separation membrane and a re-liquefaction mode in which the mixed gas compressed by the compression unit is supplied to the condenser.

3. a condenser capable of condensing the mixed gas compressed in the compression section; an expansion valve capable of adiabatically expanding the mixed gas condensed by the condenser; Further comprising: a reliquefaction device that reliquefies the mixed gas is configured by the compression unit, the condenser, and the expansion valve, The condenser also serves as the cooling unit, 2. The float according to claim 1, further comprising a switching unit that can switch between an ammonia recovery mode in which the mixed gas compressed by the compression unit is supplied to the separation membrane and the ammonia separated by the separation membrane is supplied to the condenser, and a re-liquefaction mode in which the mixed gas compressed by the compression unit is supplied to the condenser without passing through the separation membrane.

4. A supply line that supplies the ammonia stored in the tank to a combustion device as fuel; a gas supply device capable of supplying the other gas from the tank to the combustion device via the supply line; a temporary storage section into which the ammonia remaining inside the combustion device and the supply line is introduced together with the other gases supplied to the combustion device through the supply line; a recovery line connecting the temporary storage section and the tank and returning the ammonia vaporized in the temporary storage section together with the other gases into the tank; The floating body according to any one of claims 1 to 3, further comprising:

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