Ammonia-based systems

Abstract

An ammonia-using system 100 comprises a tank 1 that stores liquid ammonia, a pressurizer 2 that is in fluid communication with the tank 1 and pressurizes liquid ammonia or gaseous ammonia, a reducing valve Vd that reduces the pressure of ammonia pressurized by the pressurizer, a liquid / gas separation vessel 4 that separates liquid ammonia and gaseous ammonia generated by the pressure reduction, ammonia disposal devices 5, 6 that dispose of gaseous ammonia from the liquid / gas separation vessel 4, and a return line P5 that returns liquid ammonia from the liquid / gas separation vessel 4 to the tank 1.

Description

[Technical Field]

[0001] This disclosure relates to a system that uses ammonia. This application claims the benefit of priority from Japanese Patent Application No. 2022-49707, filed on March 25, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] Ammonia is used in a variety of systems. For example, Patent Document 1 discloses a power generation facility including a boiler that uses ammonia as fuel. In this power generation facility, liquid ammonia stored in a tank is pressurized by a pump. The pressurized liquid ammonia is heated and vaporized in a vaporizer. The gaseous ammonia is supplied to the boiler and combusted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-203637 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, when shutting down a system such as the one described above, pressurized or heated ammonia remaining in the piping may be purged from the piping to prevent leaks. However, in such a system, returning the pressurized or heated ammonia directly to the tank would lead to an increase in pressure and temperature within the tank. Therefore, when purging the ammonia, the ammonia must be decompressed. Furthermore, because ammonia is toxic, it cannot be released directly into the atmosphere. Therefore, for example, the purged ammonia may be disposed of by dissolving it in water or burning it in a flare stack. However, disposing of the ammonia results in economic losses.

[0005] The present disclosure aims to provide a system that uses ammonia, which can reduce the amount of ammonia that is wasted. [Means for solving the problem]

[0006] A system according to one aspect of the present disclosure includes a tank for storing liquid ammonia, a compressor fluidly connected to the tank and pressurizing liquid ammonia or gaseous ammonia, a pressure reducing valve for reducing the pressure of the ammonia pressurized by the compressor, a gas-liquid separation tank for separating gaseous ammonia and liquid ammonia generated by the pressure reduction, an ammonia disposal device for disposing of the gaseous ammonia from the gas-liquid separation tank, and a return line for returning liquid ammonia from the gas-liquid separation tank to the tank. a heat exchanger provided between the pressurizer and the pressure reducing valve, for cooling the ammonia pressurized by the pressurizer with the gaseous ammonia from the gas-liquid separation tank; Equipped with.

[0007] The system may include a pump in the return line that draws liquid ammonia from the gas-liquid separation vessel and delivers the liquid ammonia to the tank.

[0009] The ammonia sent from the pressurizer to the pressure reducing valve may be liquid ammonia.

[0010] The ammonia sent from the pressurizer to the pressure reducing valve may be gaseous ammonia.

[0011] The ammonia disposal system may include at least one of a water abatement tank or a flare stack. [Effects of the Invention]

[0012] According to the present disclosure, the amount of ammonia that is wasted can be reduced. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing a system according to the first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing a system according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present disclosure are not shown.

[0015] 1 is a schematic diagram showing a system 100 according to a first embodiment. For example, the system 100 includes a tank 1, a compressor 2, a gas turbine 3, a gas-liquid separation tank 4, a water removal tank 5, a flare stack 6, a pump 7, and a control device 90. The system 100 may further include other components. Furthermore, the system 100 may not include one or more of the above components.

[0016] The system 100 may use the ammonia stored in the tank 1 for various purposes. In this embodiment, the system 100 uses ammonia as fuel to be burned in the combustor 31 of the gas turbine 3. In another embodiment, the system 100 may include a boiler that burns the ammonia and a steam turbine that is operated by steam generated in the boiler. In yet another embodiment, the system 100 may be a plant that produces products using ammonia as a raw material. The system 100 is not limited to these and may include various facilities that use ammonia.

[0017] Tank 1 stores ammonia. Specifically, tank 1 stores liquid ammonia. Tank 1 is connected to pressurizer 2 by pipe P1. The liquid ammonia stored in tank 1 is supplied to pressurizer 2 via pipe P1.

[0018] The compressor 2 compresses the ammonia from the tank 1. The compressor 2 supplies the compressed ammonia to the gas turbine 3. In this embodiment, the ammonia is supplied to the gas turbine 3 in a liquid state. In this case, the compressor 2 may be a pump, for example. In another embodiment, the system 100 may include a vaporizer in the pipe P1, and the ammonia may be supplied to the gas turbine 3 in a gaseous state. In the case where the compressor 2 compresses gaseous ammonia, the compressor 2 may be a compressor, for example.

[0019] A pipe P2 branches off from the pipe P1. The pipe P2 is connected to the tank 1. The pipe P2 can return the ammonia that has passed through the pressurizer 2 to the tank 1.

[0020] A valve V1 is provided in the pipe P2. The valve V1 may be communicably connected to the control device 90 via wire or wirelessly, and may be controlled by the control device 90. The control device 90 adjusts the pressure in the pipe P1 downstream of the pressurizer 2 and the pipe P2 by controlling the opening degree of the valve V1.

[0021] For example, downstream of the branch point of the pipe P2, the pipe P1 branches into a pipe P3 connected to the gas turbine 3 and a pipe P4 connected to the gas-liquid separation tank 4. In other embodiments, for example, the pipe P1 may branch into the pipe P3 and the pipe P4 upstream of the branch point of the pipe P2, and the pipe P2 may branch off from the pipe P3 or the pipe P4.

[0022] A valve V2 is provided in the pipe P3. The valve V2 may be communicably connected to the control device 90 via wire or wirelessly, and may be controlled by the control device 90. The control device 90 adjusts the amount of ammonia supplied to the gas turbine 3 by controlling the opening degree of the valve V2.

[0023] The gas turbine 3 includes a combustor 31 and a turbine 32. The combustor 31 burns the ammonia supplied from the tank 1. The exhaust gas generated in the combustor 31 is supplied to the turbine 32 and used for operations such as power generation.

[0024] A pressure reducing valve Vd is provided in the pipe P4. The pressure reducing valve Vd may be connected to the control device 90 via wire or wireless communication and may be controlled by the control device 90. For example, the control device 90 may close the pressure reducing valve Vd when there is no need to discard the ammonia, and may open the pressure reducing valve Vd when there is a need to discard the ammonia, for example, when the system 100 is stopped and the ammonia is purged from the pipe P1. A primary side (high-pressure side) of the pressure reducing valve Vd is fluidly connected to the compressor 2, and a secondary side (low-pressure side) is fluidly connected to the gas-liquid separation tank 4. Therefore, when the pressure reducing valve Vd is opened, the ammonia pressurized by the compressor 2 is decompressed as it passes through the pressure reducing valve Vd.

[0025] When liquid ammonia passes through pressure reducing valve Vd, part of the liquid ammonia vaporizes due to flash evaporation caused by the reduced pressure. Therefore, liquid ammonia and gaseous ammonia are sent from pressure reducing valve Vd to gas-liquid separation tank 4. The ammonia sent to gas-liquid separation tank 4 is separated into liquid ammonia and gaseous ammonia. Liquid ammonia accumulates in the lower part of gas-liquid separation tank 4, and gaseous ammonia accumulates in the upper part of gas-liquid separation tank 4.

[0026] When gaseous ammonia passes through pressure reducing valve Vd, part of the gaseous ammonia is cooled by adiabatic expansion due to the reduced pressure and condenses into liquid ammonia. Therefore, in this case as well, liquid ammonia and gaseous ammonia are sent from pressure reducing valve Vd to gas-liquid separation tank 4. The ammonia sent to gas-liquid separation tank 4 is separated into liquid ammonia and gaseous ammonia. Liquid ammonia accumulates in the lower part of gas-liquid separation tank 4, and gaseous ammonia accumulates in the upper part of gas-liquid separation tank 4.

[0027] The gas-liquid separation tank 4 is connected to the tank 1 by a pipe (return line) P5. A pump 7 is provided in the pipe P5. The pump 7 sucks the liquid ammonia accumulated in the gas-liquid separation tank 4 and returns the liquid ammonia to the tank 1. The suction by the pump 7 also reduces the pressure in the gas-liquid separation tank 4. Furthermore, because the water removal tank 5 and the flare stack 6 in a state where a valve V3 (described later) is open are at atmospheric pressure, the gas-liquid separation tank 4 can be reduced in pressure even without suction by the pump 7. Therefore, a portion of the gaseous ammonia accumulated in the gas-liquid separation tank 4 can be condensed into liquid ammonia. Therefore, the amount of liquid ammonia accumulated in the gas-liquid separation tank 4, i.e., the amount of liquid ammonia returned to the tank 1, can be increased.

[0028] The gas-liquid separation tank 4 is connected to the water removal tank 5 by a pipe P6. The ammonia gas in the gas-liquid separation tank 4 is sent to the water removal tank 5 by the pipe P6. A check valve Vc is provided in the pipe P6. The check valve Vc prevents the fluid in the water removal tank 5 from flowing back into the gas-liquid separation tank 4.

[0029] The gaseous ammonia is dissolved in water in the water removal tank 5. For example, the water that has absorbed the ammonia may be discarded.

[0030] The gas-liquid separation tank 4 is connected to the flare stack 6 via a pipe P7. The gaseous ammonia in the gas-liquid separation tank 4 is sent to the flare stack 6 via the pipe P7. A valve V3 is provided in the pipe P7. The valve V3 may be connected to a control device 90 so as to be able to communicate with the control device 90 via a wired or wireless connection, and may be controlled by the control device 90. The control device 90 adjusts the amount of ammonia supplied to the flare stack 6 by controlling the opening degree of the valve V3.

[0031] In the flare stack 6, the gaseous ammonia is combusted. Because ammonia has poor combustibility, the flare stack 6 may further use another fuel with good combustibility for a pilot fire. For example, when the gaseous ammonia in the gas-liquid separation tank 4 can be disposed of in the water removal tank 5, the control device 90 may close the valve V3. When the gaseous ammonia in the gas-liquid separation tank 4 cannot be disposed of in the water removal tank 5, for example, when the water removal tank 5 is filled with water that has absorbed ammonia, the control device 90 may open the valve V4 to send the gaseous ammonia in the gas-liquid separation tank 4 to the flare stack 6.

[0032] As described above, in this embodiment, the system 100 includes the water removal tank 5 and the flare stack 6 as an ammonia disposal device that disposes of the gaseous ammonia from the gas-liquid separation tank.

[0033] The control device 90 controls all or part of the system 100. The control device 90 includes components such as a processor 90a, a storage device 90b, and a connector 90c, which are connected to one another via a bus. For example, the processor 90a includes a CPU (Central Processing Unit). For example, the storage device 90b includes a hard disk, a ROM for storing programs, and a RAM as a work area. The control device 90 is connected to each component of the system 100 via the connector 90c so as to be able to communicate with them via wired or wireless communication. For example, the control device 90 may further include other components, such as a display device such as a liquid crystal display or a touch panel, and an input device such as a keyboard, buttons, or a touch panel. For example, the above-described operation of the control device 90 may be realized by the processor 90a executing a program stored in the storage device 90b.

[0034] The system 100 described above includes a tank 1 for storing liquid ammonia, a compressor 2 fluidly connected to the tank 1 and pressurizing liquid or gaseous ammonia, a pressure-reducing valve Vd for reducing the pressure of the ammonia pressurized by the compressor 2, a gas-liquid separation tank 4 for separating the gaseous ammonia generated by the pressure reduction from the liquid ammonia, a water abatement tank 5 and a flare stack 6 for disposing of the gaseous ammonia from the gas-liquid separation tank 4, and a return line P5 for returning the liquid ammonia from the gas-liquid separation tank 4 to the tank 1. With this configuration, when the liquid ammonia pressurized by the compressor 2 passes through the pressure-reducing valve Vd, some of the liquid ammonia is vaporized by flash evaporation due to the reduced pressure. Subsequently, the liquid ammonia and the gaseous ammonia are separated from each other in the gas-liquid separation tank 4. Therefore, it is possible to return some of the liquid ammonia pressurized by the compressor 2 to the tank 1 in a reduced pressure state. Furthermore, when the gaseous ammonia pressurized by the compressor 2 passes through the pressure-reducing valve Vd, some of the gaseous ammonia is cooled by adiabatic expansion due to the reduced pressure and condenses into liquid ammonia. Subsequently, the liquid ammonia and the gaseous ammonia are separated from each other in the gas-liquid separation tank 4. Therefore, in this case as well, it is possible to return a portion of the gaseous ammonia pressurized by the pressurizer 2 to the tank 1 in a decompressed and liquefied state. Therefore, with the above-described configuration, it is possible to reduce the amount of ammonia that is discarded.

[0035] The system 100 also includes a pump 7 provided in the return line P5, which sucks liquid ammonia from the gas-liquid separation tank 4 and sends the liquid ammonia to the tank 1. With this configuration, the pressure in the gas-liquid separation tank 4 is reduced by the suction from the pump 7. This can promote the condensation of a portion of the gaseous ammonia accumulated in the gas-liquid separation tank 4 into liquid ammonia. This can increase the amount of liquid ammonia returned to the tank 1.

[0036] In the system 100, the ammonia sent from the compressor 2 to the pressure reducing valve Vd may be liquid ammonia or gaseous ammonia. In either case, a portion of the ammonia pressurized by the compressor 2 can be returned to the tank 1 in a depressurized state, thereby reducing the amount of ammonia wasted.

[0037] In addition, in system 100, the ammonia disposal device includes water abatement tank 5 or flare stack 6. For example, in other embodiments, the ammonia disposal device may include at least one of water abatement tank 5 or flare stack 6. The ammonia disposal device is not limited to these, and may be other devices capable of disposing of gaseous ammonia.

[0038] Next, a system according to another embodiment will be described.

[0039] 2 is a schematic diagram showing a system 100A according to a second embodiment. The system 100A differs from the system 100 according to the first embodiment in that the system 100A includes a heat exchanger 8. In other respects, the system 100A may be the same as the system 100 according to the first embodiment.

[0040] The heat exchanger 8 is disposed in the pipe P6 between the gas-liquid separation tank 4 and the water removal tank 5. In another embodiment, the heat exchanger 8 may be disposed in the pipe P7, instead of the pipe P6, between the gas-liquid separation tank 4 and the flare stack 6. The heat exchanger 8 is also disposed in the pipe P1, between the pressurizer 2 and the pressure reducing valve Vd. In another embodiment, the heat exchanger 8 may be disposed in the pipe P4, instead of the pipe P1, between the pressurizer 2 and the pressure reducing valve Vd. In the heat exchanger 8, the ammonia pressurized by the pressurizer 2 is cooled by the gaseous ammonia from the gas-liquid separation tank 4. According to this configuration, a larger amount of liquid ammonia can be obtained by reducing the pressure in the pressure reducing valve Vd.

[0041] The system 100A as described above has the same effects as the system 100 according to the first embodiment. In particular, the system 100A includes a heat exchanger 8 that is provided between the pressurizer 2 and the pressure reducing valve Vd and that cools the ammonia pressurized by the pressurizer 2 with the gaseous ammonia from the gas-liquid separation tank 4. With this configuration, a larger amount of liquid ammonia can be obtained by reducing the pressure in the pressure reducing valve Vd. Therefore, the amount of liquid ammonia returned to the tank 1 can be increased.

[0042] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that such modifications also fall within the technical scope of the present disclosure.

[0043] For example, in the above embodiments, the systems 100 and 100A include the pump 7. In other embodiments, the system may not include the pump 7. In this case, for example, the pressure reducing valve Vd may be controlled so that the internal pressure of the gas-liquid separation tank 4 is higher than the internal pressure of the tank 1. The pressure difference between the gas-liquid separation tank 4 and the tank 1 causes liquid ammonia to flow from the gas-liquid separation tank 4 to the tank 1. In this case, since some of the liquid ammonia from the gas-liquid separation tank 4 may be vaporized in the tank 1, the system may further include a boil-off gas (BOG) compressor connected to the tank 1. The vaporized ammonia can be converted back to liquid ammonia by the BOG compressor. Furthermore, for example, the gas-liquid separation tank 4 may be located at a high position so that the internal pressure of the gas-liquid separation tank 4 is higher than the internal pressure of the tank 1.

[0044] The present disclosure can promote the use of ammonia, which leads to reduced CO2 emissions, and can therefore contribute to, for example, Sustainable Development Goal (SDG) 7, "Ensure access to affordable, reliable, sustainable and modern energy." [Explanation of symbols]

[0045] 1 tank 2. Pressure generator 4 Gas-liquid separation tank 4A Gas-liquid separation tank 5. Water removal tank (ammonia disposal device) 6. Flare stack (ammonia disposal equipment) 7. Pump 8 Heat exchanger 41 Chamber 1 42 Second Chamber 100 systems 100A System P5 piping (return line) Vd Pressure Reducing Valve

Claims

1. a tank for storing liquid ammonia; a pressurizer in fluid communication with the tank for pressurizing liquid or gaseous ammonia; a pressure reducing valve that reduces the pressure of the ammonia pressurized by the compressor; a gas-liquid separation tank for separating gaseous ammonia and liquid ammonia generated by the pressure reduction; an ammonia disposal device that disposes of the gaseous ammonia from the gas-liquid separation tank; a return line for returning liquid ammonia from the gas-liquid separation tank to the tank; a heat exchanger provided between the pressurizer and the pressure reducing valve, for cooling the ammonia pressurized by the pressurizer with the gaseous ammonia from the gas-liquid separation tank; A system using ammonia comprising:

2. 2. The system of claim 1, further comprising a pump provided in the return line, the pump sucking liquid ammonia from the gas-liquid separation tank and sending the liquid ammonia to the tank.

3. 3. The system according to claim 1, wherein the ammonia sent from the pressurizer to the pressure reducing valve is liquid ammonia.

4. 3. The system of claim 1, wherein the ammonia delivered from the pressurizer to the pressure reducing valve is gaseous ammonia.

5. 3. The system of claim 1 or 2, wherein the ammonia disposal device includes at least one of a water abatement tank or a flare stack.

6. 4. The system of claim 3, wherein the ammonia disposal device comprises at least one of a water abatement tank or a flare stack.

7. 5. The system of claim 4, wherein the ammonia disposal device includes at least one of a water abatement tank or a flare stack.

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