Ammonia supply system

Abstract

This technology provides a way to determine whether or not gaseous ammonia, before being supplied to a pressure regulator, contains a large amount of liquid ammonia. [Solution] The ammonia supply system comprises a vaporizer for vaporizing liquid ammonia, a densimeter for measuring the density of the gaseous ammonia after vaporization by the vaporizer, and a pressure regulator for adjusting the pressure of the gaseous ammonia after its density has been measured by the densimeter.

Description

Technical Field

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[0001] The technology disclosed in this specification relates to an ammonia supply system.

Background Art

[0002] Patent Document 1 discloses a fuel supply system. The fuel supply system of Patent Document 1 includes fuel supply means for supplying fuel to an injector of an internal combustion engine in a liquid phase state, and vaporization state detection means for detecting the vaporization state of the fuel in the injector. The vaporization state detection means of Patent Document 1 is constituted by, for example, temperature detection means for detecting the engine temperature of the internal combustion engine.

[0003] In recent years, technologies using ammonia as fuel have been developed. As this type of technology, for example, an ammonia supply system has been developed in which liquid ammonia is vaporized by a vaporizer to generate gaseous ammonia, and the gaseous ammonia is supplied to a predetermined supply destination (for example, a reformer or an engine).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In ammonia supply systems, the pressure of gaseous ammonia after vaporization by a vaporizer is adjusted by a pressure regulator, and the regulated gaseous ammonia is then supplied to a designated destination. In this configuration, when liquid ammonia is vaporized by the vaporizer, some of the liquid ammonia may remain unvaporized. As a result, this unvaporized liquid ammonia may be supplied to the pressure regulator mixed with the gaseous ammonia. Problems can arise in such cases. For example, the supply of liquid ammonia to the pressure regulator may cause deterioration of the seal rubber, a component of the pressure regulator. Therefore, it is important to understand the condition of the gaseous ammonia supplied to the pressure regulator.

[0006] Therefore, this specification provides a technology that can determine whether or not gaseous ammonia, before being supplied to a pressure regulator, contains a large amount of liquid ammonia. [Means for solving the problem]

[0007] In a first aspect of this technology, the ammonia supply system includes a vaporizer for vaporizing liquid ammonia, a densimeter for measuring the density of gaseous ammonia after vaporization by the vaporizer, and a pressure regulator for adjusting the pressure of gaseous ammonia after its density has been measured by the densimeter.

[0008] With this configuration, by measuring the density of gaseous ammonia using a densimeter, it is possible to determine whether or not the gaseous ammonia after vaporization by the vaporizer contains a large amount of liquid ammonia. In other words, it is possible to determine whether or not the gaseous ammonia before being supplied to the pressure regulator contains a large amount of liquid ammonia.

[0009] In a second embodiment, the ammonia supply system may further include, in the first embodiment, a first flow path for sending gaseous ammonia, whose density has been measured by the densimeter, to the pressure regulator; a second flow path for sending gaseous ammonia, whose density has been measured by the densimeter, to the vaporizer without sending it to the pressure regulator; and a switching valve capable of switching between a first state in which gaseous ammonia is sent to the pressure regulator via the first flow path and a second state in which gaseous ammonia is sent to the vaporizer via the second flow path.

[0010] With this configuration, by switching the switching valve to the second state, gaseous ammonia containing a large amount of liquid ammonia can be returned to the vaporizer through the second flow path. This allows the liquid ammonia to be vaporized again in the vaporizer. As a result, the supply of liquid ammonia to the pressure regulator can be suppressed. [Brief explanation of the drawing]

[0011] [Figure 1] A schematic block diagram showing the ammonia supply system of the example. [Modes for carrying out the invention]

[0012] The ammonia supply system 2 of the embodiment will be described with reference to the drawings. As shown in Figure 1, the ammonia supply system 2 of the embodiment comprises an ammonia tank 4, a vaporizer 10, a densimeter 50, a switching valve 70, a pressure regulator 30, a reformer 80, an engine 82, and a control device 100. The ammonia supply system 2 also comprises a liquid ammonia supply channel 20 and a gaseous ammonia supply channel 40.

[0013] The ammonia supply system 2 is a system that generates gaseous ammonia by vaporizing liquid ammonia and supplies the generated gaseous ammonia to a predetermined supply destination (for example, a reformer 80, an engine 82, etc.).

[0014] Ammonia tank 4 stores liquid ammonia. A liquid ammonia supply channel 20 is connected to ammonia tank 4. The upstream end of the liquid ammonia supply channel 20 is connected to ammonia tank 4, and the downstream end is connected to vaporizer 10. The liquid ammonia supply channel 20 supplies liquid ammonia from ammonia tank 4 to vaporizer 10. A pump (not shown) may be provided in the liquid ammonia supply channel 20 to pump liquid ammonia from the upstream side (ammonia tank 4 side) to the downstream side (vaporizer 10 side).

[0015] The vaporizer 10 is a device that vaporizes liquid ammonia supplied through the liquid ammonia supply channel 20. For example, the vaporizer 10 vaporizes liquid ammonia by heating it. The vaporizer 10 produces gaseous ammonia by vaporizing liquid ammonia. A gaseous ammonia supply channel 40 is connected to the vaporizer 10. The upstream end of the gaseous ammonia supply channel 40 is connected to the vaporizer 10, and the downstream end is connected to a predetermined gaseous ammonia supply destination (for example, a reformer 80, an engine 82, etc.). The gaseous ammonia supply channel 40 supplies gaseous ammonia from the vaporizer 10 to the predetermined supply destination.

[0016] In the vaporizer 10, when liquid ammonia is vaporized, some of the liquid ammonia may remain unvaporized. Therefore, the gaseous ammonia produced in the vaporizer 10 may contain the unvaporized liquid ammonia. Consequently, the gaseous ammonia flowing through the gaseous ammonia supply channel 40 may contain liquid ammonia. The type and configuration of the vaporizer 10 are not particularly limited. For example, the vaporizer 10 may have a configuration in which a double-walled tube is wound in a coil shape.

[0017] The gaseous ammonia supply channel 40 comprises a main channel 42 and a plurality of branch channels (for example, a first branch channel 141, a second branch channel 142, a third branch channel 143, and a fourth branch channel 144) branching off from the main channel 42. The upstream end of the main channel 42 is connected to the vaporizer 10, and the downstream ends of each branch channel 141, 142, 143, and 144 are connected to predetermined supply destinations (for example, a reformer 80, an engine 82, etc.).

[0018] The main channel 42 of the gaseous ammonia supply channel 40 is equipped with a densimeter 50, a switching valve 70, and a pressure regulator 30. The densimeter 50 is installed in the main channel 42 upstream of the switching valve 70. The densimeter 50 measures the density of gaseous ammonia flowing through the main channel 42. The densimeter 50 measures the density of gaseous ammonia after it has been vaporized by the vaporizer 10. The densimeter 50 measures the density of gaseous ammonia between the vaporizer 10 and the pressure regulator 30. In this case, if the gaseous ammonia flowing through the main channel 42 contains liquid ammonia (i.e., if the gaseous ammonia produced in the vaporizer 10 contains liquid ammonia that remains unvaporized in the vaporizer 10), the densimeter 50 measures the density of the gaseous ammonia containing the liquid ammonia. The type and configuration of the densimeter 50 are not particularly limited. For example, a vibrating densimeter, a float densimeter, or a radiation densimeter can be used as the densimeter 50.

[0019] The switching valve 70 is located between the densimeter 50 and the pressure regulator 30. The switching valve 70 is located in the main flow path 42 downstream of the densimeter 50 and upstream of the pressure regulator 30. The switching valve 70 is configured, for example, as a three-way valve. A return flow path 60 is connected to the switching valve 70. The switching valve 70 can be switched between a first state in which gaseous ammonia flows from the main flow path 42 upstream of the switching valve 70 to the main flow path 42 downstream of the switching valve 70, and a second state in which gaseous ammonia flows from the main flow path 42 upstream of the switching valve 70 to the return flow path 60. In the first state, gaseous ammonia does not flow into the return flow path 60, and in the second state, gaseous ammonia does not flow into the main flow path 42 downstream of the switching valve 70.

[0020] The return flow path 60 has its upstream end connected to the switching valve 70 and its downstream end connected to the liquid ammonia supply flow path 20. The return flow path 60 supplies gaseous ammonia (more specifically, gaseous ammonia containing liquid ammonia) from the main flow path 42 of the gaseous ammonia supply flow path 40 to the liquid ammonia supply flow path 20. An ejector (not shown) may be provided at the connection portion between the return flow path 60 and the liquid ammonia supply flow path 20. Gaseous ammonia may be supplied from the return flow path 60 to the liquid ammonia supply flow path 20 via the ejector.

[0021] A check valve 62 is provided in the return flow path 60. The check valve 62 allows gaseous ammonia to flow from the upstream side (the switching valve 70 side) to the downstream side (the liquid ammonia supply flow path 20 side) of the return flow path 60 and prohibits gaseous ammonia from flowing from the downstream side to the upstream side of the return flow path 60.

[0022] The pressure regulator 30 is provided in the main flow path 42 on the downstream side of the densitometer 50 and also on the downstream side of the switching valve 70. The pressure regulator 30 is a device that adjusts (for example, reduces the pressure) the pressure of the gaseous ammonia flowing through the main flow path 42 on the downstream side of the switching valve 70. The pressure regulator 30 adjusts (for example, reduces the pressure) the pressure of the gaseous ammonia after the density has been measured by the densitometer 50. The pressure regulator 30 reduces the pressure of the gaseous ammonia, for example, by adiabatically expanding the gaseous ammonia. The type and configuration of the pressure regulator 30 are not particularly limited.

[0023] <亮氨酸> The gaseous ammonia supply flow path 40 on the downstream side of the pressure regulator 30 branches into a plurality of branch flow paths (for example, the first branch flow path 141, the second branch flow path 142, the third branch flow path 143, and the fourth branch flow path 144).

[0024] The downstream end of the first branch flow path 141 and the downstream end of the second branch flow path 142 are each connected to the reformer 80. The first branch flow path 141 and the second branch flow path 142 each supply gaseous ammonia, after the pressure has been adjusted by the pressure regulator 30, to the reformer 80. The first injector 121 is provided in the first branch flow path 141. Similarly, the second injector 122 is provided in the second branch flow path 142. When the first injector 121 is in the open state, gaseous ammonia is supplied to the reformer 80 through the first branch flow path 141. When the first injector 121 is in the closed state, the supply of gaseous ammonia to the reformer 80 stops. The same applies to the second injector 122 as to the first injector 121.

[0025] The downstream end of the third branch flow path 143 and the downstream end of the fourth branch flow path 144 are each connected to the engine 82. The third branch flow path 143 and the fourth branch flow path 144 each supply gaseous ammonia, after the pressure has been adjusted by the pressure regulator 30, to the engine 82. The third injector 123 is provided in the third branch flow path 143. Similarly, the fourth injector 124 is provided in the fourth branch flow path 144. When the third injector 123 is in the open state, gaseous ammonia is supplied to the engine 82 through the third branch flow path 143. When the third injector 123 is in the closed state, the supply of gaseous ammonia to the engine 82 stops. The same applies to the fourth injector 124 as to the third injector 123.

[0026] The control device 100 includes, for example, a CPU, ROM, and RAM, and performs control and processing related to the ammonia supply system 2 based on a predetermined program. For example, the control device 100 controls the state of the switching valve 70 based on the density measured by the densimeter 50. For example, the control device 100 switches the switching valve 70 to the first state when the density measured by the densimeter 50 is below a predetermined threshold. That is, the control device 100 switches the switching valve 70 to the first state when the amount of liquid ammonia contained in the gaseous ammonia after vaporization by the vaporizer 10 is relatively small. As a result, the gaseous ammonia after vaporization by the vaporizer 10 is supplied to the pressure regulator 30.

[0027] On the other hand, the control device 100 switches the switching valve 70 to the second state when the density measured by the densimeter 50 is above a predetermined threshold. In other words, the control device 100 switches the switching valve 70 to the second state when the amount of liquid ammonia contained in the gaseous ammonia after vaporization by the vaporizer 10 is relatively large. As a result, the gaseous ammonia containing a large amount of liquid ammonia is returned to the liquid ammonia supply channel 20 through the return channel 60. The gaseous ammonia returned to the liquid ammonia supply channel 20 (gasseous ammonia containing a large amount of liquid ammonia) is supplied to the vaporizer 10 through the liquid ammonia supply channel 20. In the vaporizer 10, the liquid ammonia contained in the gaseous ammonia is vaporized again.

[0028] (effect) The ammonia supply system 2 of the embodiment has been described above. As is clear from the above description, the ammonia supply system 2 includes a densimeter 50 for measuring the density of gaseous ammonia after it has been vaporized by the vaporizer 10, and a pressure regulator 30 for adjusting the pressure of gaseous ammonia after its density has been measured by the densimeter 50.

[0029] With this configuration, by measuring the density of gaseous ammonia with the densimeter 50, it is possible to determine whether or not the gaseous ammonia after vaporization by the vaporizer 10 contains a large amount of liquid ammonia. In other words, it is possible to determine whether or not the gaseous ammonia before being supplied to the pressure regulator 30 contains a large amount of liquid ammonia.

[0030] Furthermore, the ammonia supply system 2 is equipped with a main flow path 42 (an example of a first flow path) that sends gaseous ammonia, whose density has been measured by the densimeter 50, to the pressure regulator 30. The ammonia supply system 2 is also equipped with a return flow path 60 (an example of a second flow path) that sends gaseous ammonia, whose density has been measured by the densimeter 50, to the vaporizer 10 without sending it to the pressure regulator 30. The ammonia supply system 2 is also equipped with a switching valve 70, which can switch between a first state in which gaseous ammonia is sent to the pressure regulator 30 via the main flow path 42, and a second state in which gaseous ammonia is sent to the vaporizer 10 via the return flow path 60.

[0031] With this configuration, by switching the switching valve 70 to the second state, gaseous ammonia containing a large amount of liquid ammonia can be returned to the vaporizer 10 through the return passage 60. This allows the liquid ammonia to be vaporized again in the vaporizer 10. As a result, the supply of liquid ammonia to the pressure regulator 30 can be suppressed.

[0032] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of symbols]

[0033] 2: Ammonia supply system, 4: Ammonia tank, 10: Vaporizer, 20: Liquid ammonia supply channel, 30: Pressure regulator, 40: Gaseous ammonia supply channel, 42: Main channel, 50: Densimeter, 60: Return channel, 62: Check valve, 70: Switching valve, 80: Reformer, 82: Engine, 100: Control device

Claims

1. A vaporizer that vaporizes liquid ammonia, A densimeter for measuring the density of gaseous ammonia after it has been vaporized by the aforementioned vaporizer, An ammonia supply system comprising a pressure regulator for adjusting the pressure of gaseous ammonia after its density has been measured by the aforementioned densimeter.

2. The ammonia supply system according to claim 1, A first flow path that sends gaseous ammonia, whose density has been measured by the densimeter, to the pressure regulator, A second flow path that sends the gaseous ammonia, whose density has been measured by the aforementioned density meter, to the vaporizer without sending it to the pressure regulator, An ammonia supply system further comprising a switching valve capable of switching between a first state in which gaseous ammonia is supplied to the pressure regulator through the first flow path, and a second state in which gaseous ammonia is supplied to the vaporizer through the second flow path.

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