Ammonia gas piping facility, floating body, and method for controlling ammonia gas piping facility

Abstract

This ammonia gas piping facility comprises: an inner tube that forms an inner space inside which ammonia gas flows through; an outer tube that surrounds the inner tube from the outer periphery and forms an outer space between the outer tube and the inner tube; a fluid introduction unit that introduces, into the outer space, a replacement fluid to replace the ammonia gas leaked from the inner tube; a fluid discharge unit that is provided at a distance from the fluid introduction unit in the flow direction of the ammonia gas and discharges the replacement fluid from the outer space; and a temperature adjustment unit that heats the replacement fluid before the replacement fluid is introduced into the outer space.

Description

Ammonia gas piping equipment, floating body, and method for controlling ammonia gas piping equipment

[0001] This application claims priority to Japanese Patent Application No. 2023-138366, filed on August 28, 2023, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 describes a ship that generates navigation power by burning fuel gas such as LNG (liquefied natural gas) in a gas engine. Patent Document 1 also describes a configuration that employs a so-called double-pipe structure in which a fuel supply pipe (inner pipe) is surrounded by a duct (outer pipe) to constantly ventilate the space between the fuel supply pipe and the duct, from the perspective of preventing accidents in the event of a leak in the gas fuel supply system.

[0003] Japanese Patent Application Laid-Open No. 2022-97162

[0004] Incidentally, ammonia is sometimes used as a decarbonized fuel in combustion devices such as engines and boilers. Even when ammonia is used as a fuel, it is recommended to use a double-pipe piping structure, as described in Patent Document 1, to prevent leakage. Ammonia as a fuel may be supplied to a consumer in a gaseous state, more specifically, in a superheated steam state. However, when using a double-pipe structure such as that described in Patent Document 1, i.e., when constantly ventilating the space between the inner and outer pipes to allow ammonia gas leaking from the inner pipe to be replaced with a fluid, the saturation temperature of ammonia gas at the same pressure is higher than that of natural gas, so the ammonia gas may undergo a phase change and condense. If ammonia liquid forms inside the inner pipe, it becomes impossible to deliver ammonia as a gas to the combustion device. Furthermore, the combustion device using ammonia gas as fuel and the piping through which the ammonia gas flows may be damaged due to a water hammer phenomenon or the like.

[0005] The present disclosure has been made in consideration of the above circumstances, and provides an ammonia gas piping facility, a floating body, and a method for controlling an ammonia gas piping facility that can replace leaked ammonia gas while reducing the risk of ammonia gas condensation and damage to combustion equipment and piping.

[0006] In order to solve the above problems, the following configuration is adopted: According to one aspect of the present disclosure, an ammonia gas piping system includes an inner pipe that forms an inner space inside through which ammonia gas flows, an outer pipe that surrounds the inner pipe from the outer peripheral side and forms an outer space between the inner pipe and the outer pipe, a fluid inlet that introduces a replacement fluid to replace ammonia gas leaked from the inner pipe into the outer space, a fluid outlet that is provided apart from the fluid inlet in the flow direction of the ammonia gas and that discharges the replacement fluid from the outer space, and a temperature adjustment unit that heats the replacement fluid before being introduced into the outer space.

[0007] According to one aspect of the present disclosure, a floating body includes an ammonia gas piping facility, an ammonia gas supply device that supplies the ammonia gas, and a combustion device that uses the ammonia gas as fuel.

[0008] According to one aspect of the present disclosure, a method for controlling an ammonia gas piping facility is a method for controlling an ammonia gas piping facility, comprising the step of heating the replacement fluid so that the temperature of the replacement fluid discharged from the inner pipe is equal to or lower than the temperature of the replacement fluid introduced into the inner pipe.

[0009] According to one aspect of the present disclosure, a method for controlling an ammonia gas piping facility is a method for controlling an ammonia gas piping facility, comprising the step of heating the replacement fluid so that the temperature of the ammonia gas in the downstream portion of the inner pipe is equal to or higher than the temperature of the ammonia gas in the upstream portion of the inner pipe.

[0010] According to the present disclosure, it is possible to condense ammonia gas and replace leaked ammonia gas, while reducing the risk of damage to combustion equipment and piping.

[0011] FIG. 1 is a diagram showing a schematic configuration of a floating body in a first embodiment of the present disclosure. FIG. 2 is a diagram showing a schematic configuration of an ammonia gas piping facility in a first embodiment of the present disclosure. FIG. 3 is a diagram showing a hardware configuration of a control device in a first embodiment of the present disclosure. FIG. 4 is a functional block diagram of a control device in a first embodiment of the present disclosure. FIG. 5 is a flowchart of a control method for an ammonia gas piping facility in a first modified example of the first embodiment of the present disclosure. FIG. 6 is a flowchart of a control method for an ammonia gas piping facility in a second modified example of the first embodiment of the present disclosure. FIG. 7 is a diagram showing a schematic configuration of an ammonia gas piping facility in a second embodiment of the present disclosure. FIG. 8 is a diagram showing a schematic configuration of an ammonia gas piping facility in a third embodiment of the present disclosure.

[0012] An ammonia gas piping system, a float, and a method for controlling an ammonia gas piping system according to an embodiment of the present disclosure will now be described with reference to the drawings. First Embodiment (Floating Body) FIG. 1 is a diagram showing a schematic configuration of a float according to a first embodiment of the present disclosure. As shown in FIG. 1, the float 1 of the first embodiment includes at least a float body 2, an upper structure 4, a combustion device 8, an ammonia tank 10, an ammonia fuel conditioning room 20, and an ammonia gas piping system 30. The float 1 of this embodiment will be described as an example of a ship capable of navigation using a main engine or the like. The type of the float 1 is not limited to a specific type of ship. Examples of ship types include liquefied gas carriers equipped with ammonia-fueled combustion devices, ferries, RORO ships, car carriers, passenger ships, ammonia transport ships, and multipurpose gas carriers capable of transporting ammonia and liquefied gases other than ammonia. Examples of the float 1 include an ammonia FSU (Floating Storage Unit), an ammonia FSRU (Floating Storage and Regasification Unit), and the like.

[0013] (Floating body main body) The floating body main body 2 has a pair of side panels 5A, 5B that form its outer hull, and a bottom 6. The side panels 5A, 5B are equipped with a pair of side panel shells that form the port and starboard sides, respectively. The bottom 6 is equipped with a bottom panel shell that connects the side panels 5A, 5B. The floating body main body 2 of this embodiment further comprises an upper deck 7, which is a full-length deck located at the top. The superstructure 4 is formed on the upper deck 7, and has accommodation areas and the like provided inside. In the floating body 1 of this embodiment, for example, a cargo space (not shown) for carrying cargo is provided closer to the bow 3a in the bow-stern direction FA than the superstructure 4.

[0014] (Combustion Device) The combustion device 8 is a device that generates thermal energy by burning fuel, and is provided inside the floating body main body 2. Examples of the combustion device 8 include an internal combustion engine that serves as a power source for propelling the floating body 1, an internal combustion engine used in a power generation facility that supplies electricity on board, and a boiler that generates steam as a working fluid. The combustion device 8 exemplified in this embodiment is an internal combustion engine that serves as a power source for propelling the floating body 1, and is capable of switching between ammonia and other fuels different from ammonia, such as heavy oil, as the fuel.

[0015] (Ammonia Tank) The ammonia tank 10 is a tank that stores liquid ammonia (hereinafter referred to as liquefied ammonia). The ammonia tank 10 of this embodiment is a fuel tank that stores liquefied ammonia that serves as fuel for the combustion device 8. The ammonia tank 10 exemplified in this first embodiment is installed on the upper deck 7 closer to the bow 3 a than the superstructure 4, but this arrangement of the ammonia tank 10 is just an example, and the arrangement of the ammonia tank 10 is not limited to being on the upper deck 7 closer to the bow 3 a than the superstructure 4.

[0016] (Ammonia fuel conditioning chamber) The ammonia fuel conditioning chamber 20 is equipped with various ammonia fuel devices (not shown) that vaporize the liquefied ammonia supplied from the ammonia tank 10. The ammonia fuel conditioning chamber 20 adjusts the pressure and temperature of the ammonia gas Ga so that the vaporized ammonia gas Ga is in a superheated vapor region. The ammonia fuel conditioning chamber 20 also adjusts the temperature of the ammonia gas Ga so that it falls within the temperature range required by the combustion device 8. The ammonia fuel conditioning chamber 20 corresponds to the ammonia gas supply device in this disclosure.

[0017] (Ammonia gas piping equipment) Figure 2 is a diagram showing a schematic configuration of an ammonia gas piping equipment in the first embodiment of the present disclosure. The ammonia gas piping equipment 30 supplies ammonia gas Ga as fuel to the combustion device 8. The ammonia gas piping equipment 30 of this embodiment guides the ammonia gas Ga vaporized by the ammonia fuel adjustment chamber 20 to the combustion device 8. The ammonia gas piping equipment 30 includes an inner pipe 31, an outer pipe 32, a fluid inlet 33, a fluid outlet 34, a temperature adjustment unit 35, a plurality of sensors 50, and a control device 51.

[0018] The inner pipe 31 defines an inner space 40 inside thereof through which ammonia gas Ga flows. The inner pipe 31 of the present embodiment guides the temperature- and pressure-adjusted ammonia gas Ga from the ammonia fuel preparation chamber 20 to the combustion device 8. Here, the temperature and pressure of the ammonia gas Ga are adjusted in the ammonia fuel preparation chamber 20 so as to fall within the temperature and pressure ranges required by the combustion device 8.

[0019] The outer pipe 32 surrounds the inner pipe 31 from the outer peripheral side and forms an outer space 41 between the inner pipe 31 and the outer pipe 32. In other words, the inner pipe 31 and the outer pipe 32 form a so-called double pipe structure. The outer pipe 32 can be formed to surround the inner pipe 31, for example, in a region that cannot accommodate ammonia leakage, within the region between the ammonia fuel conditioning chamber 20 and the combustion device 8. The outer pipe 32 may, for example, cover the entire inner pipe 31 in the extending direction of the inner pipe 31, or may cover a portion of the inner pipe 31 in the extending direction of the inner pipe 31.

[0020] The fluid introduction section 33 introduces a replacement fluid Fr into the outer space 41 to replace ammonia gas Ga leaked from the inner pipe 31. The replacement fluid Fr is a fluid for replacing leaked ammonia gas Ga when ammonia gas Ga leaks from the inner pipe 31 into the outer space 41. In this embodiment, outside air (ventilation air) taken in by a fan or the like for ventilation of the floating body 1 is used. The fluid introduction section 33 in this embodiment is provided near one end of the outer pipe 32 in the extension direction. The fluid introduction section 33 in this embodiment is provided on the side closer to the combustion device 8, in other words, near the end of the outer pipe 32 on the most downstream side Dfd in the flow direction Df of the ammonia gas Ga. The fluid introduction section 33 may be provided, for example, at the end of the outer pipe 32 on the most downstream side Dfd in the flow direction Df of the ammonia gas Ga.

[0021] The fluid discharge part 34 discharges the replacement fluid Fr from the outer space 41. The fluid discharge part 34 is provided at a distance from the fluid introduction part 33 in the flow direction Df of the ammonia gas Ga. In this embodiment, the fluid discharge part 34 is provided at a position close to the other end, which is the end opposite to the one end, in the extension direction of the outer pipe 32. In this embodiment, the fluid discharge part 34 is provided on the side closer to the ammonia fuel conditioning chamber 20, in other words, near the end of the most upstream Dfu in the flow direction Df of the ammonia gas Ga. The fluid discharge part 34 may be provided, for example, at the end of the outer pipe 32 at the most upstream Dfu in the flow direction Df of the ammonia gas Ga.

[0022] That is, the replacement fluid Fr in this embodiment flows into the outer space 41 from the fluid inlet 33, flows through the outer space 41 from the downstream side Dfd to the upstream side Dfu in the flow direction Df of the ammonia gas Ga, and is discharged to the outside of the outer space 41 from the fluid outlet 34. Note that, although the present embodiment illustrates a case in which the replacement fluid Fr flows countercurrently to the ammonia gas Ga, this is not limited to a countercurrent flow. The replacement fluid Fr may also flow parallel to the ammonia gas Ga. Furthermore, the flow rate of the replacement fluid Fr flowing through the outer space 41 in this embodiment is always constant, but the flow rate of the replacement fluid Fr flowing through the outer space 41 may vary.

[0023] The temperature adjustment unit 35 heats the replacement fluid Fr before it is introduced into the outer space 41. In other words, the temperature adjustment unit 35 is capable of raising the temperature of the replacement fluid Fr to a desired temperature before it is introduced into the outer space 41. The temperature adjustment unit 35 of this embodiment is capable of raising the temperature of the replacement fluid Fr to a temperature equal to or higher than the temperature of the ammonia gas Ga flowing through the inner space 40. Examples of the temperature adjustment unit 35 include a heater and a heat exchanger. The temperature adjustment unit 35 is controlled by a control device 51.

[0024] (Sensors) The multiple sensors 50 detect at least one of the temperature of the replacement fluid Fr and the temperature of the ammonia gas Ga in the inner space 40. The detection results by the multiple sensors 50 are input to the control device 51. In this embodiment, the multiple sensors 50 include a first temperature sensor 50a that detects a temperature T1 of the replacement fluid Fr in the fluid inlet portion 33, a second temperature sensor 50b that detects a temperature T2 of the replacement fluid Fr in the fluid outlet portion 34, a third temperature sensor 50c that detects a temperature Ta1 of the ammonia gas Ga in the upstream portion of the inner pipe 31, a fourth temperature sensor 50d that detects a temperature Ta2 of the ammonia gas Ga in the downstream portion of the inner pipe 31, a first pressure sensor 50e that detects a pressure Pa1 of the ammonia gas Ga in the upstream portion of the inner pipe 31, and a second pressure sensor 50f that detects a pressure Pa2 of the ammonia gas Ga in the downstream portion of the inner pipe 31. In this embodiment, the first temperature sensor 50a detects the temperature T1 of the replacement fluid Fr just before it is introduced into the outer space 41, and the second temperature sensor 50b detects the temperature T2 of the replacement fluid Fr just after it is discharged from the outer space 41.

[0025] Here, the upstream portion of the inner pipe 31 is the portion of the inner pipe 31 adjacent to the end of the outer space 41 at the most upstream side Dfu in the flow direction Df. The downstream portion of the inner pipe 31 is the portion of the inner pipe 31 adjacent to the end of the outer space 41 at the most downstream side Dfd in the flow direction Df. In other words, the temperature Ta1 and the pressure Pa1 are the temperature and pressure of the ammonia gas Ga immediately before it flows into the double-pipe structure, and the temperature Ta2 and the pressure Pa2 are the temperature and pressure of the ammonia gas Ga immediately after it flows out of the double-pipe structure.

[0026] (Control Device) Fig. 3 is a diagram showing a hardware configuration of a control device in the first embodiment of the present disclosure. Fig. 4 is a functional block diagram of the control device in the first embodiment of the present disclosure. As shown in Fig. 3, the control device 51 is a computer including a CPU (Central Processing Unit) 61, a ROM (Read Only Memory) 62, a RAM (Random Access Memory) 63, a storage 64 such as an HDD (Hard Disk Drive), and a signal transmission / reception module 65.

[0027] As shown in FIG. 4, the CPU 61 of the control device 51 executes programs stored in the ROM 62 and storage 64 to realize the functional configurations of a temperature acquisition unit 71, a pressure acquisition unit 72, a temperature control unit 73, and a command signal output unit 74.

[0028] The temperature acquisition unit 71 acquires at least one of the temperature of the replacement fluid Fr and the temperature of the ammonia gas Ga. As shown in Figures 2 and 4, the temperature acquisition unit 71 of this embodiment acquires temperatures T1 and T2 of the replacement fluid Fr and temperatures Ta1 and Ta2 of the ammonia gas Ga from the first temperature sensor 50a, the second temperature sensor 50b, the third temperature sensor 50c, and the fourth temperature sensor 50d, respectively. Note that in the first embodiment, acquisition of the temperature Ta1 may be omitted.

[0029] The pressure acquiring unit 72 acquires the pressure of the ammonia gas Ga. The pressure acquiring unit 72 in this embodiment acquires the pressures Pa1 and Pa2 of the ammonia gas Ga from the first pressure sensor 50e and the second pressure sensor 50f, respectively. Note that in the first embodiment, acquisition of the pressure Pa1 may be omitted. For example, when the pressure Pa1 is acquired, it can be confirmed that the ammonia gas Ga flowing in the upstream portion of the inner pipe 31 is superheated vapor based on the temperature Ta1 and the pressure Pa1.

[0030] The temperature control unit 73 controls the temperature adjustment unit 35 based on the temperature acquired by the temperature acquisition unit 71. The temperature control unit 73 of this embodiment controls the temperature adjustment unit 35 based on the temperature acquired by the temperature acquisition unit 71 and the pressure acquired by the pressure acquisition unit 72. Furthermore, the temperature control unit 73 of this embodiment controls the temperature adjustment unit 35 so that the temperature T2 of the replacement fluid Fr in the fluid discharge unit 34 is equal to or lower than the temperature T1 of the replacement fluid Fr in the fluid introduction unit 33 (T1≧T2).

[0031] Furthermore, the temperature control unit 73 of this embodiment controls the temperature adjustment unit 35 based on the pressure P2 of ammonia gas Ga at the downstream portion of the inner pipe 31 and the temperature Ta2 of ammonia gas Ga at the downstream portion of the inner pipe 31, while satisfying the condition T1≧T2, so that the temperature Ta2 of ammonia gas Ga at the downstream portion of the inner pipe 31 falls within the superheated vapor range. Here, since the saturation temperature of ammonia gas Ga can be calculated from the pressure P2, the temperature control unit 73 controls the temperature adjustment unit 35 so that the temperature Ta2 falls within the superheated vapor range with a predetermined margin from the saturation temperature, while satisfying the condition T1≧T2. Note that if an upper limit temperature of ammonia gas Ga is determined at the supply destination (combustion device 8) of ammonia gas Ga, the temperature control unit 73 may control the temperature adjustment unit 35 so that the temperature Ta2 does not exceed this upper limit temperature.

[0032] The command signal output unit 74 outputs a command signal for controlling the temperature adjustment unit 35 , which is output from the temperature control unit 73 , to the temperature adjustment unit 35 .

[0033] (Method for controlling ammonia gas piping equipment) Fig. 5 is a flowchart of a method for controlling ammonia gas piping equipment in the first embodiment of the present disclosure. As shown in Fig. 5, the method for controlling ammonia gas piping equipment 30 in the first embodiment includes a step S10 of heating the replacement fluid so that the temperature of the replacement fluid discharged from the outer space is equal to or lower than the temperature of the replacement fluid introduced into the outer space, and a step S11 of heating the replacement fluid so that the temperature of ammonia gas Ga in the downstream part of the inner pipe is in the superheated vapor region.

[0034] In step S10, the replacement fluid Fr is heated so that the temperature of the replacement fluid discharged from the outer space 41 is equal to or lower than the temperature of the replacement fluid introduced into the outer space. The replacement fluid Fr is heated so that temperature T2 is equal to or lower than temperature T1. That is, in step S10, the temperature of the replacement fluid Fr is increased so that the replacement fluid Fr introduced into the outer space 41 does not remove thermal energy from the ammonia gas Ga in the inner space 40. For example, if temperature T2 is higher than temperature T1, it is estimated that the thermal energy of the ammonia gas Ga has been transferred to the replacement fluid Fr. Therefore, in step S10, if temperature T2 is higher than temperature T1, the temperature adjustment unit 35 increases the temperature of the replacement fluid Fr before it is introduced into the outer space 41. On the other hand, if temperature T2 is equal to or lower than temperature T1, the process proceeds to the next step.

[0035] In step S11, the replacement fluid is heated so that the temperature of the ammonia gas Ga downstream of the inner pipe reaches the superheated vapor region. The saturation temperature of the ammonia gas Ga is calculated based on the pressure Pa2, and the replacement fluid Fr is heated based on the calculated saturation temperature so that the temperature Ta2 reaches the superheated vapor region. In step S11, if the temperature Ta2 is not in the superheated vapor region, the temperature of the replacement fluid Fr is increased until the temperature Ta2 reaches the superheated vapor region. On the other hand, if the temperature Ta2 is in the superheated vapor region, the process returns to step S10.

[0036] (Operation and Effect) In the first embodiment described above, the ammonia gas piping equipment 30 includes the temperature adjustment unit 35 that heats the replacement fluid Fr before it is introduced into the outer space 41 between the inner pipe 31 and the outer pipe 32 that form the double-pipe structure. This configuration, for example, can suppress a decrease in the temperature of the replacement fluid Fr, thereby suppressing a decrease in the temperature of the ammonia gas Ga that occurs due to heat exchange between the ammonia gas Ga flowing through the inner space 40 of the inner pipe 31 and the replacement fluid Fr. This can prevent the ammonia gas Ga flowing through the inner space 40 of the inner pipe 31 from condensing and becoming liquefied. Therefore, while enabling ammonia gas Ga leaking from the inner pipe 31 to the outer space 41 to be replaced with the replacement fluid Fr, it is possible to ensure that ammonia is delivered to the combustion device 8 in a gaseous state and reduce the risk of damage to the combustion device 8 or the piping system through which the ammonia gas Ga flows due to ammonia droplets.

[0037] Furthermore, in the first embodiment, the control device 51 includes a temperature acquisition unit 71 that acquires the temperature of at least one of the replacement fluid Fr and the ammonia gas Ga, and a temperature control unit 73 that controls the temperature adjustment unit 35 based on the temperature acquired by the temperature acquisition unit 71. With this configuration, when the replacement fluid Fr takes away the thermal energy of the ammonia gas Ga and the temperature of the ammonia gas Ga decreases, the replacement fluid Fr can be automatically heated to suppress the decrease in the temperature of the ammonia gas Ga.

[0038] Furthermore, in the first embodiment, the temperature acquisition unit 71 acquires the temperature T1 of the replacement fluid Fr in the fluid inlet 33 and the temperature T2 of the replacement fluid Fr in the fluid outlet 34. The temperature control unit 73 controls the temperature adjustment unit 35 so that the temperature T2 of the replacement fluid Fr in the fluid outlet 34 is equal to or lower than the temperature T1 of the replacement fluid Fr in the fluid inlet 33. This makes it possible to prevent the replacement fluid Fr introduced from the fluid inlet 33 into the outer space 41 from increasing in temperature when it is discharged from the fluid outlet 34, i.e., to prevent the enthalpy of the replacement fluid Fr from increasing as a result of flowing through the outer space 41. This makes it possible to prevent the thermal energy of the ammonia gas Ga from being transferred to the replacement fluid Fr.

[0039] Furthermore, in the first embodiment, a pressure acquisition unit 72 is provided that acquires the pressure Pa2 of the ammonia gas Ga at the downstream portion of the inner pipe 31. The temperature acquisition unit 71 further acquires the temperature Ta2 of the ammonia gas Ga at the downstream portion of the inner pipe 31. The temperature control unit 73 controls the temperature adjustment unit 35 based on the pressure Pa2 and the temperature Ta2 so that the temperature Ta2 of the ammonia gas Ga at the downstream portion of the inner pipe 31 is in the superheated vapor range. This makes it possible to maintain the state of the ammonia gas Ga flowing through the inner pipe 31 as superheated vapor. Therefore, condensation of the ammonia gas Ga flowing through the inner pipe 31 can be further suppressed.

[0040] First Modification of First Embodiment Figure 6 is a flowchart of a control method for an ammonia gas piping system in a first modification of the first embodiment of the present disclosure. In the first embodiment described above, the temperatures T1 and T2 of the replacement fluid Fr are acquired, and the temperature adjustment unit 35 is controlled so that the temperature T2 is equal to or lower than the temperature T1. However, this configuration is not limiting. For example, the temperature control unit 73 may control the temperature adjustment unit 35 so that the temperature Ta2 of the ammonia gas Ga is equal to or higher than the temperature Ta1. In other words, as shown in Figure 6, instead of step S10 of Figure 5, step S20 may be performed in which the replacement fluid is heated so that the temperature of the ammonia gas at the downstream portion of the inner pipe is equal to or higher than the temperature of the ammonia gas at the upstream portion of the inner pipe.

[0041] Furthermore, without being limited to the configuration of the first modified example, for example, the temperature control unit 73 may control the temperature adjustment unit 35 so that the temperature T2 is equal to or lower than the temperature T1 (T1≧T2) and the temperature Ta2 is equal to or higher than the temperature Ta1 (Ta2≧Ta1). The temperature control unit 73 may also control the temperature adjustment unit 35 so that the above-mentioned T1≧T2 and Ta2≧Ta1 hold and the temperature Ta2 of the ammonia gas Ga at the downstream portion of the inner pipe 31 becomes the temperature of the superheated vapor region based on the pressure Pa2 and temperature Ta2 of the ammonia gas Ga at the downstream portion of the inner pipe 31. This provides redundancy.

[0042] 7 is a flowchart of a control method for an ammonia gas piping system in a second modification of the first embodiment of the present disclosure. In the above-described first embodiment and the first modification of the first embodiment, the control for heating the replacement fluid Fr based on the temperatures T1 and T2 of the replacement fluid Fr and the temperatures Ta1 and Ta2 of the ammonia gas Ga has been described. However, this configuration is not limited thereto. For example, when it is estimated that the ammonia gas Ga flowing through the inner pipe 31 is not superheated vapor, the temperature control unit 73 may control the temperature adjustment unit 35 to heat the replacement fluid Fr so that the ammonia gas Ga becomes superheated vapor.

[0043] As shown in Fig. 7, the control method for ammonia gas piping equipment according to the second modification of the first embodiment includes a step S30 of determining whether ammonia gas is in a superheated vapor state and a step S31 of heating the replacement fluid so that the temperature of the ammonia gas in the downstream portion is in the superheated vapor region. In step S30, it is determined whether the ammonia gas Ga is in a superheated vapor state in the downstream portion. Specifically, the saturation temperature of the ammonia gas Ga is calculated based on the pressure Pa2, and it is determined whether the temperature Ta2 is in the superheated vapor region with a predetermined margin from the saturation temperature. As a result of the determination in step S30, if it is determined that the temperature Ta2 of the ammonia gas Ga is not in the superheated vapor region with a predetermined margin from the saturation temperature ("No" in S30), the process proceeds to step S31. In step S31, the temperature of the replacement fluid Fr is increased until the temperature Ta2 falls within the superheated vapor region. However, when the temperature Ta2 falls within the superheated vapor region with a predetermined margin from the saturation temperature, the heating of the replacement fluid Fr is stopped, and the process returns to step S30.

[0044] According to this second variant, when the temperature of the ammonia gas Ga in the downstream part of the inner pipe 31 drops and it is likely that it will no longer be superheated vapor, the replacement fluid Fr can be heated to raise the temperature of the ammonia gas Ga in the downstream part, thereby maintaining the state of superheated vapor, thereby suppressing condensation of the ammonia gas Ga.

[0045] Second Embodiment Next, a second embodiment of the present disclosure will be described with reference to the drawings. This second embodiment differs from the first embodiment described above only in that the humidity of the replacement fluid Fr is reduced. Therefore, the same parts as those in the first embodiment described above will be denoted by the same reference numerals and redundant description will be omitted.

[0046] Fig. 8 is a diagram showing a schematic configuration of an ammonia gas piping system according to a second embodiment of the present disclosure. As shown in Fig. 8, the ammonia gas piping system 130 according to the second embodiment includes an inner pipe 31, an outer pipe 32, a fluid inlet 33, a fluid outlet 34, a temperature adjuster 35, a plurality of sensors 50, and a control device 51, similar to the ammonia gas piping system 30 according to the first embodiment. In addition to the above configuration, the ammonia gas piping system 130 according to the second embodiment further includes a dehumidifier 80. The ammonia gas piping system 130 according to the second embodiment uses ventilation air as the replacement fluid Fr.

[0047] The dehumidifier 80 dehumidifies ventilation air, which is the replacement fluid Fr introduced from the fluid introduction section 33 into the outer space 41. The dehumidifier 80 of this embodiment is installed upstream of the replacement fluid Fr relative to the temperature adjustment section 35 (on the opposite side from the outer pipe 32). Examples of the dehumidifier 80 include dehumidifiers of an adsorption type or a refrigeration type. The location of the dehumidifier 80 is not limited to the above installation position, and it may be installed, for example, between the temperature adjustment section 35 and the outer pipe 32.

[0048] (Effects) According to the second embodiment, the humidity of the replacement fluid Fr can be reduced, and therefore, for example, it is possible to suppress condensation of water in the replacement fluid Fr in the outer space 41. Therefore, when ammonia gas Ga leaks, it is possible to suppress water that has absorbed the ammonia gas Ga (ammonia water) from remaining in the outer space 41.

[0049] Modification of Second Embodiment In the second embodiment, the case where the dehumidifier 80 is provided has been described. However, this is not limited to this. For example, a low dew point gas may be used as the replacement fluid Fr without providing the dehumidifier 80. Here, the low dew point gas can be obtained by increasing the pressure of the ventilation air to condense and separate the moisture contained in the ventilation air. For example, in a floating body 1 such as a ship, compressed air used to start an internal combustion engine can be decompressed and used as the low dew point gas.

[0050] Third Embodiment Next, a third embodiment of the present disclosure will be described with reference to the drawings. This third embodiment differs from the first embodiment described above only in that a heat shield is provided. Therefore, the same parts as those in the first embodiment described above will be denoted by the same reference numerals and redundant description will be omitted.

[0051] Fig. 9 is a diagram showing a schematic configuration of an ammonia gas piping facility according to a third embodiment of the present disclosure. As shown in Fig. 9, the ammonia gas piping facility 230 according to the third embodiment includes, similarly to the ammonia gas piping facility 30 according to the first embodiment, an inner pipe 31, an outer pipe 32, a fluid inlet 33, a fluid outlet 34, a temperature adjuster 35, a plurality of sensors 50, and a control device 51. In addition to the above configuration, the ammonia gas piping facility 230 according to the third embodiment further includes a heat insulating unit 90.

[0052] The heat insulating portion 90 suppresses heat radiation from the outer surface of the outer pipe 32. In this embodiment, the heat insulating portion 90 is installed so as to cover the outer surface of the outer pipe 32. Examples of the heat insulating portion 90 include glass wool and a foam material made of synthetic resin (e.g., urethane). Note that the heat insulating portion 90 may have any configuration as long as it is capable of preventing heat radiation from the outer surface of the outer pipe 32.

[0053] (Effects) According to the third embodiment, the replacement fluid Fr flowing through the outer space 41 can be kept warm. Therefore, the energy required to heat the replacement fluid Fr can be reduced. Note that a heat insulating section 90 may be provided on the outer pipe 32 of the ammonia gas piping equipment 130 of the second embodiment.

[0054] Other Embodiments The present disclosure is not limited to the configurations of the above-described embodiments, and design modifications are possible within the scope of the present disclosure. For example, in the above-described embodiments and modified examples of the embodiments, the ammonia gas piping equipment 30 is provided on the floating body 1, but the ammonia gas piping equipment 30 is not limited to being provided on the floating body 1. For example, the ammonia gas piping equipment 30 may be applied to a land-based facility having a combustion device that uses ammonia as fuel.

[0055] Furthermore, in the above-described embodiments and modified examples of the embodiment, the float 1 is described as a float primarily used for navigation on water. However, the float 1 is not limited to a float primarily used for navigation on water. The float 1 may be, for example, an ammonia FSU or an ammonia FSRU, which is never or rarely used for navigation on water. In this case, for example, liquefied ammonia stored in a storage tank (not shown) provided within the float body 1 may be supplied to the ammonia fuel conditioning chamber 20 to be converted into superheated steam. The ammonia gas converted into superheated steam in the ammonia fuel conditioning chamber 20 may then be supplied via the ammonia gas piping system 30 to a fuel system (not shown) external to the float 1 or to a combustion device such as a power generation facility within the float that is not a power source. The arrangement of the storage tank (not shown) within the float body is not limited in any way.

[0056] In addition, in the above-described embodiments and modified examples of the embodiments, the ammonia tank 10 is a fuel tank, but the ammonia tank 10 may be a cargo tank (not shown) that stores liquefied ammonia as cargo. Furthermore, in the above-described embodiments and modified examples of the embodiments, the case where one combustion device 8, one piping system 30, 130, 230, and one ammonia tank 10 are provided on one floating body 1 is exemplified, but the number of each is not limited to one. There may be a plurality of each of the combustion device 8, the piping system 30, 130, 230, and the ammonia tank 10, as necessary.

[0057] In addition, in the above-described embodiments and modifications of the embodiments, the temperature control unit 73 adjusts the temperature adjustment unit 35 so that the ammonia gas Ga is in the superheated vapor range, but this configuration is not limiting. For example, the temperature control unit 73 may control the temperature adjustment unit 35 based only on the temperatures T1 and T2, or may control the temperature adjustment unit 35 based only on the temperatures Ta1 and Ta2.

[0058] Furthermore, in the above-described embodiments and modified examples, the case where outside air is used as the replacement fluid Fr has been described as an example, but the replacement fluid Fr may also be a liquid. Examples of liquid replacement fluids Fr include clean water and antifreeze containing a rust inhibitor. Furthermore, a portion of the replacement fluid Fr discharged from the fluid discharge portion 34 may be returned to the fluid introduction portion 33 and circulated in the outer space 41. Furthermore, in the above-described embodiments and modified examples, the case where the temperature Ta2 is raised to a temperature in the superheated steam range with a predetermined margin from the saturation temperature has been described. However, the predetermined margin may be set as appropriate or may be omitted.

[0059] <Additional Notes> The ammonia gas piping equipment, the floating body, and the method for controlling the ammonia gas piping equipment described in each embodiment can be understood, for example, as follows.

[0060] (1) According to a first aspect, the ammonia gas piping equipment 30, 130, 230 includes an inner pipe 31 that forms an inner space 40 inside the inner pipe 31 through which ammonia gas Ga flows, an outer pipe 32 that surrounds the inner pipe 31 from the outer periphery and forms an outer space 41 between the inner pipe 31 and the outer pipe 32, a fluid inlet 33 that introduces a replacement fluid Fr to replace the ammonia gas Ga leaked from the inner pipe 31 into the outer space 41, a fluid outlet 34 that is provided apart from the fluid inlet 33 in the flow direction Df of the ammonia gas Ga and that discharges the replacement fluid Fr from the outer space 41, and a temperature adjustment unit 35 that heats the replacement fluid Fr before being introduced into the outer space 41. Examples of the replacement fluid include ventilation air, fresh water, and antifreeze.

[0061] This prevents the temperature of the ammonia gas Ga from decreasing, making it possible to replace the ammonia gas Ga that leaks from the inner tube 31 into the outer space 41 with the replacement fluid Fr, while reducing the risk of damage to the combustion device 8 or the piping system through which the ammonia gas Ga flows due to ammonia droplets.

[0062] (2) According to a second aspect, the ammonia gas piping equipment 30, 130, 230 is the ammonia gas piping equipment 30, 130, 230 of (1), and is provided with a control device 51 that controls the temperature adjustment unit 35, and the control device 51 is provided with a temperature acquisition unit 71 that acquires the temperature of at least one of the replacement fluid Fr and the ammonia gas Ga, and a temperature control unit 73 that controls the temperature adjustment unit 35 based on the temperature acquired by the temperature acquisition unit 71.

[0063] As a result, in a situation where the thermal energy of the ammonia gas Ga is taken away and the temperature of the ammonia gas Ga drops, the replacement fluid Fr is automatically heated, and the drop in the temperature of the ammonia gas Ga can be suppressed.

[0064] (3) According to a third aspect, the ammonia gas piping equipment 30, 130, 230 is the ammonia gas piping equipment 30, 130, 230 of (2), in which the temperature acquisition unit 71 acquires a temperature T1 of the replacement fluid Fr at the fluid inlet 33 and a temperature T2 of the replacement fluid Fr at the fluid outlet 34, and the temperature control unit 73 controls the temperature adjustment unit 35 so that the temperature T2 of the replacement fluid Fr at the fluid outlet 34 is equal to or lower than the temperature T1 of the replacement fluid Fr at the fluid inlet 33. This makes it possible to suppress an increase in enthalpy of the replacement fluid Fr due to flow through the outer space 41. Therefore, it is possible to suppress the thermal energy of the ammonia gas Ga from being transferred to the replacement fluid Fr.

[0065] (4) According to a fourth aspect, the ammonia gas piping equipment 30, 130, 230 is the ammonia gas piping equipment 30, 130, 230 of (3), further comprising a pressure acquisition unit 72 that acquires the pressure of the ammonia gas Ga in the downstream portion of the inner pipe 31, the temperature acquisition unit 71 further acquires the temperature Ta2 of the ammonia gas Ga in the downstream portion, and the temperature control unit 73 controls the temperature adjustment unit 35 based on the pressure Pa2 of the ammonia gas Ga in the downstream portion and the temperature Ta2 of the ammonia gas Ga in the downstream portion so that the temperature Ta2 of the ammonia gas Ga in the downstream portion is in the superheated vapor range. This makes it possible to maintain the state of the ammonia gas Ga flowing through the inner pipe 31 as superheated vapor. Therefore, it is possible to further suppress condensation of the ammonia gas Ga flowing through the inner pipe 31.

[0066] (5) According to a fifth aspect, the ammonia gas piping equipment 30, 130, 230 is the ammonia gas piping equipment 30, 130, 230 of (2), in which the temperature acquisition unit 71 acquires a temperature Ta1 of the ammonia gas Ga at the upstream portion of the inner pipe 31 and a temperature Ta2 of the ammonia gas Ga at the downstream portion of the inner pipe 31, and the temperature control unit 73 controls the temperature adjustment unit 35 so that the temperature Ta2 of the ammonia gas Ga at the downstream portion is equal to or higher than the temperature Ta1 of the ammonia gas Ga at the upstream portion. This makes it possible to suppress the thermal energy of the ammonia gas Ga from being transferred to the replacement fluid Fr.

[0067] (6) According to a sixth aspect, the ammonia gas piping equipment 30, 130, 230 is the ammonia gas piping equipment 30, 130, 230 of (5), further comprising a pressure acquisition unit 72 that acquires the pressure Pa2 of the ammonia gas Ga in the downstream portion, and the temperature control unit 73 controls the temperature adjustment unit 35 based on the pressure Pa2 of the ammonia gas Ga in the downstream portion and the temperature Ta2 of the ammonia gas Ga in the downstream portion so that the temperature Ta2 of the ammonia gas Ga in the downstream portion is in the superheated vapor range. This makes it possible to maintain the state of the ammonia gas Ga flowing through the inner pipe 31 as superheated vapor. Therefore, it is possible to further suppress condensation of the ammonia gas Ga flowing through the inner pipe 31.

[0068] (7) According to a seventh aspect, the ammonia gas piping equipment 30, 130, 230 is the ammonia gas piping equipment 30, 130, 230 of (2), further comprising a pressure acquisition unit 72 that acquires the pressure Pa2 of the ammonia gas Ga in the downstream portion of the inner pipe 31, the temperature acquisition unit 71 further acquires the temperature Pa2 of the ammonia gas Ga in the downstream portion, and the temperature control unit 73 controls the temperature adjustment unit 35 based on the pressure Pa2 of the ammonia gas Ga in the downstream portion and the temperature Ta2 of the ammonia gas Ga in the downstream portion so that the temperature Ta2 of the ammonia gas Ga in the downstream portion is in the superheated vapor range. As a result, when the ammonia gas Ga in the downstream portion of the inner pipe 31 is likely to no longer be superheated vapor due to a drop in temperature Ta2, the replacement fluid Fr is heated to increase the temperature of the ammonia gas Ga in the downstream portion, thereby making it possible to maintain the state of superheated vapor, and therefore condensation of the ammonia gas Ga can be suppressed.

[0069] (8) According to an eighth aspect, the ammonia gas piping equipment 30, 130, 230 is any one of the ammonia gas piping equipment 30, 130, 230 of (1) to (7), wherein the replacement fluid Fr is ventilation air, and further includes a dehumidifier 80 that dehumidifies the ventilation air introduced into the outer space 41 from the fluid introduction part 33. This makes it possible to prevent water that has absorbed the ammonia gas Ga from remaining in the outer space 41 when the ammonia gas Ga leaks.

[0070] (9) According to a ninth aspect, the ammonia gas piping equipment 30, 130, 230 is any one of the ammonia gas piping equipment 30, 130, 230 of (1) to (8), and the replacement fluid Fr is a low dew point gas. This makes it possible to prevent water that has absorbed the ammonia gas Ga from remaining in the outer space 41 when the ammonia gas Ga leaks.

[0071] (10) According to a tenth aspect, the ammonia gas piping equipment 30, 130, 230 is any one of the ammonia gas piping equipment 30, 130, 230 according to (1) to (9), and further includes a heat insulating part 90 that suppresses heat radiation from the outer surface of the outer pipe 32. This makes it possible to keep the replacement fluid Fr flowing through the outer space 41 warm, thereby reducing the energy required to heat the replacement fluid Fr.

[0072] (11) According to an eleventh aspect, the floating body 1 includes any one of the ammonia gas piping facilities 30, 130, 230 of (1) to (10), an ammonia gas supply device 20 that supplies the ammonia gas Ga, and a combustion device 8 that uses the ammonia gas Ga as fuel. Examples of the ammonia gas supply device include various ammonia fuel devices provided in an ammonia fuel adjustment chamber. This makes it possible to suppress condensation of the ammonia gas Ga used as fuel without complicating the configuration of the floating body 1.

[0073] (12) According to a twelfth aspect, the control method for ammonia gas piping equipment is the control method for any one of the ammonia gas piping equipment 30, 130, 230 according to (1) to (10), and includes a step S10 of heating the replacement fluid Fr so that a temperature T2 of the replacement fluid Fr discharged from the inner pipe 31 is equal to or lower than a temperature T1 of the replacement fluid Fr introduced into the inner pipe 31. This makes it possible to suppress the thermal energy of the ammonia gas Ga from being transferred to the replacement fluid Fr.

[0074] (13) According to a thirteenth aspect, the control method for ammonia gas piping equipment is the control method for any one of the ammonia gas piping equipment 30, 130, 230 according to (1) to (10), and includes a step S20 of heating the replacement fluid Fr so that a temperature Ta2 of the ammonia gas Ga in the downstream portion of the inner pipe 31 becomes equal to or higher than a temperature Ta1 of the ammonia gas Ga in the upstream portion of the inner pipe 31. This makes it possible to suppress the thermal energy of the ammonia gas Ga from being transferred to the replacement fluid Fr.

[0075] (14) According to a fourteenth aspect, the control method for ammonia gas piping equipment is the control method for the ammonia gas piping equipment 30, 130, 230 of (12) or (13), and includes a step S11 of heating the replacement fluid Fr so that the temperature Ta2 of the ammonia gas Ga in the downstream part of the inner pipe 31 is in the superheated vapor region. This makes it possible to maintain the state of the ammonia gas Ga flowing through the inner space 40 of the inner pipe 31 as superheated vapor.

[0076] (15) According to a fifteenth aspect, the control method for ammonia gas piping equipment is the control method for ammonia gas piping equipment 30, 130, 230 of (1), and includes a step S31 of heating the replacement fluid Fr so that the temperature Ta2 of the ammonia gas Ga in the downstream portion of the inner pipe 31 is in the superheated vapor region. As a result, when the ammonia gas Ga in the downstream portion of the inner pipe 31 is likely to no longer be superheated vapor due to a drop in temperature Ta2, the replacement fluid Fr is heated to increase the temperature of the ammonia gas Ga in the downstream portion, making it possible to maintain the state of superheated vapor, and therefore condensation of the ammonia gas Ga can be suppressed.

[0077] According to the present disclosure, it is possible to condense ammonia gas and replace leaked ammonia gas, while reducing the risk of damage to combustion equipment and piping.

[0078] DESCRIPTION OF SYMBOLS 1 Floating body 2 Floating body main body 3a Bow 3b Stern 4 Superstructure 5A, 5B Ship side 6 Ship bottom 7 Upper deck 8 Combustion device 10 Ammonia tank 20 Ammonia fuel adjustment room 30, 130, 230 Ammonia gas piping equipment 31 Inner pipe 32 Outer pipe 33 Fluid inlet section 34 Fluid outlet section 35 Temperature adjustment section 40 Inner space 41 Outer space 50 Sensor 50a First temperature sensor 50b Second temperature sensor 50c Third temperature sensor 50d Fourth temperature sensor 50e First pressure sensor 50f Second pressure sensor 51 Control device 61 CPU 62 ROM 63 RAM 64 Storage 65 Signal transmission / reception module 71 Temperature acquisition section 72 Pressure acquisition section 73 Temperature control section 74 Command signal output section 80 Dehumidifier 90 Heat insulating part Fr Replacement fluid Ga Ammonia gas

Claims

1. An ammonia gas piping facility comprising: an inner pipe forming an inner space inside through which ammonia gas flows; an outer pipe surrounding the inner pipe from an outer periphery and forming an outer space between the inner pipe and the outer pipe; a fluid inlet portion for introducing a replacement fluid to replace the ammonia gas leaking from the inner pipe into the outer space; a fluid outlet portion provided at a distance from the fluid inlet portion in a flow direction of the ammonia gas and for discharging the replacement fluid from the outer space; and a temperature adjustment portion for heating the replacement fluid before it is introduced into the outer space.

2. The ammonia gas piping equipment according to claim 1, further comprising a control device for controlling the temperature adjustment unit, the control device comprising: a temperature acquisition unit for acquiring a temperature of at least one of the replacement fluid and the ammonia gas; and a temperature control unit for controlling the temperature adjustment unit based on the temperature acquired by the temperature acquisition unit.

3. The ammonia gas piping equipment according to claim 2, wherein the temperature acquisition unit acquires the temperature of the replacement fluid at the fluid inlet and the temperature of the replacement fluid at the fluid outlet, and the temperature control unit controls the temperature adjustment unit so that the temperature of the replacement fluid at the fluid outlet is equal to or lower than the temperature of the replacement fluid at the fluid inlet.

4. The ammonia gas piping equipment according to claim 3, further comprising a pressure acquisition unit that acquires a pressure of the ammonia gas in a downstream portion of the inner pipe, wherein the temperature acquisition unit further acquires a temperature of the ammonia gas in the downstream portion, and wherein the temperature control unit controls the temperature adjustment unit based on the pressure of the ammonia gas in the downstream portion and the temperature of the ammonia gas in the downstream portion so that the temperature of the ammonia gas in the downstream portion is in the superheated steam range.

5. The ammonia gas piping equipment according to claim 2, wherein the temperature acquisition unit acquires the temperature of the ammonia gas in the upstream portion of the inner pipe and the temperature of the ammonia gas in the downstream portion of the inner pipe, and the temperature control unit controls the temperature adjustment unit so that the temperature of the ammonia gas in the downstream portion is equal to or higher than the temperature of the ammonia gas in the upstream portion.

6. The ammonia gas piping equipment according to claim 5, further comprising a pressure acquisition unit that acquires a pressure of the ammonia gas in the downstream portion, and the temperature control unit controls the temperature adjustment unit based on the pressure of the ammonia gas in the downstream portion and the temperature of the ammonia gas in the downstream portion so that the temperature of the ammonia gas in the downstream portion is in a superheated steam range.

7. The ammonia gas piping equipment according to claim 2, further comprising a pressure acquisition unit that acquires a pressure of the ammonia gas in a downstream portion of the inner pipe, wherein the temperature acquisition unit acquires a temperature of the ammonia gas in the downstream portion, and the temperature control unit controls the temperature adjustment unit based on the pressure of the ammonia gas in the downstream portion and the temperature of the ammonia gas in the downstream portion so that the temperature of the ammonia gas in the downstream portion is in the superheated steam range.

8. The ammonia gas piping equipment according to any one of claims 1 to 7, wherein the replacement fluid is ventilation air, and the equipment further comprises a dehumidifier that dehumidifies the ventilation air introduced into the outer space from the fluid introduction portion.

9. The ammonia gas piping equipment according to any one of claims 1 to 7, wherein the replacement fluid is a low dew point gas.

10. The ammonia gas piping equipment according to any one of claims 1 to 7, further comprising a heat insulating section for suppressing heat radiation from the outer surface of the outer pipe.

11. A float comprising: an ammonia gas piping system according to any one of claims 1 to 7; an ammonia gas supply device for supplying the ammonia gas; and a combustion device using the ammonia gas as fuel.

12. A method for controlling an ammonia gas piping system as described in claim 1, comprising a step of heating the replacement fluid so that the temperature of the replacement fluid discharged from the outer space is equal to or lower than the temperature of the replacement fluid introduced into the outer space.

13. A method for controlling an ammonia gas piping system as described in claim 1, comprising the step of heating the replacement fluid so that the temperature of the ammonia gas in the downstream portion of the inner pipe is equal to or higher than the temperature of the ammonia gas in the upstream portion of the inner pipe.

14. The method for controlling an ammonia gas piping system according to claim 12 or 13, further comprising a step of heating the replacement fluid so that the temperature of the ammonia gas in the downstream portion of the inner pipe is in a superheated vapor region.

15. A method for controlling an ammonia gas piping system as described in claim 1, comprising the step of heating the replacement fluid so that the temperature of the ammonia gas downstream of the inner pipe is in the superheated vapor region.

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