Ammonia vaporization facility

Abstract

This ammonia vaporization facility comprises: an ammonia vaporizer that vaporizes liquid ammonia; and a liquid ammonia extraction part that extracts the liquid ammonia accumulated in the ammonia vaporizer. The liquid ammonia extraction part has: a drainage pipe connected to the ammonia vaporizer; a liquid extraction pump provided at an intermediate section of the drainage pipe; and a guide portion that causes the liquid ammonia to flow to the drainage pipe in a state where the liquid extraction pump is stopped.

Description

Ammonia Vaporization Equipment

[0001] The present invention relates to ammonia vaporization equipment. The present application claims priority based on Japanese Patent Application No. 2025-051731 filed in Japan on March 26, 2025, the content of which is incorporated herein by reference.

[0002] For example, Patent Document 1 discloses a vaporizer including a shell and a supply unit that supplies liquefied gas into the shell. The vaporizer disclosed in Patent Document 1 further includes a liquid outflow unit that discharges the liquefied gas accumulated in the shell.

[0003] Japanese Unexamined Patent Publication No. 2022-6152

[0004] When vaporizing liquid ammonia using a vaporizer as disclosed in Patent Document 1, it is conceivable to use a heat medium such as seawater or warm waste water to heat and gasify the liquid ammonia while suppressing energy consumption.

[0005] In heat exchange between liquid ammonia and heat media such as seawater or warm waste water, it is difficult to evaporate all the moisture contained in the liquid ammonia, and the moisture will be concentrated and remain inside the vaporizer. For this reason, it is necessary to extract the liquid ammonia mixed with moisture from the vaporizer using a drainage pump or the like.

[0006] The pressure inside the vaporizer is the saturated vapor pressure. For this reason, the liquid ammonia handled by the drainage pump becomes a saturated liquid. On the other hand, the delivery flow rate of ammonia gas fluctuates based on load fluctuations of the supply destination and the like. Therefore, for example, when the gas delivery flow rate increases abruptly, the pressure inside the vaporizer temporarily decreases, which may cause cavitation or the like.

[0007] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to enable suppression of cavitation occurrence in a drainage pump in an ammonia vaporization equipment capable of extracting liquid ammonia accumulated in an ammonia vaporizer.

[0008] An ammonia vaporization apparatus according to one aspect of the present invention comprises an ammonia vaporizer for vaporizing liquid ammonia and a liquid ammonia extraction unit for extracting liquid ammonia accumulated in the ammonia vaporizer, wherein the liquid ammonia extraction unit includes a drain pipe connected to the ammonia vaporizer, a drain pump provided at an intermediate point in the drain pipe, and a guide unit for flowing the liquid ammonia into the drain pipe when the drain pump is stopped.

[0009] According to one aspect of the present invention, the liquid ammonia extraction unit includes a guide unit that allows liquid ammonia to flow into the drainage pipe when the extraction pump is stopped. Therefore, in cases where the pressure in the extraction pump temporarily decreases due to load fluctuations or the like, the liquid ammonia extracted from the ammonia vaporizer can be allowed to flow with the extraction pump stopped, thereby suppressing the flushing of the liquid ammonia. Consequently, in an ammonia vaporization system capable of extracting liquid ammonia accumulated in the ammonia vaporizer, the occurrence of cavitation in the extraction pump can be suppressed.

[0010] This is a schematic flowchart showing the general configuration of the ammonia vaporization equipment in the first embodiment of the present invention. This is a schematic flowchart showing the general configuration of a modified example of the ammonia vaporization equipment in the first embodiment of the present invention. This is a schematic flowchart showing the general configuration of the ammonia vaporization equipment in the second embodiment of the present invention.

[0011] Hereinafter, embodiments of the ammonia vaporization equipment according to the present invention will be described with reference to the drawings.

[0012] (First Embodiment) Figure 1 is a schematic flow diagram showing the general configuration of the ammonia vaporization equipment 1 of this embodiment. The ammonia vaporization equipment 1 of this embodiment is equipment that vaporizes liquid ammonia X stored in a low-temperature storage tank 100 (tank) to produce ammonia gas and sends the ammonia gas to the customer. In this embodiment, the low-temperature storage tank 100 is described, but the tank is not limited to low-temperature storage. For example, a spherical tank may be used instead of the low-temperature storage tank 100.

[0013] The low-temperature storage tank 100 is, for example, a large double-shelled above-ground low-temperature tank with a total height of about 50 m. The double-shelled above-ground low-temperature tank comprises a metal inner tank (not shown) and a metal outer tank, and stores liquid ammonia X transferred from a tanker or the like inside the inner tank. The internal pressure of the low-temperature storage tank 100 is lower than that of the ammonia vaporizer 2, which will be described later.

[0014] The low-temperature storage tank 100 may be an underground low-temperature tank. The storage temperature of the liquid ammonia X stored in the low-temperature storage tank 100 is, for example, around -33°C to -34°C. The liquid ammonia X stored in the low-temperature storage tank 100 also contains, for example, about 0.5 wt% water.

[0015] As shown in Figure 1, the ammonia vaporization equipment 1 of this embodiment comprises an ammonia vaporizer 2, a liquid ammonia supply unit 3, a liquid ammonia extraction unit 4, a gas supply piping 5, and an ammonia gas heat exchanger 6.

[0016] The ammonia vaporizer 2 vaporizes the liquid ammonia X supplied from the liquid ammonia supply unit 3. Inside the ammonia vaporizer 2, there is a heat exchange tube (not shown) through which a heat transfer medium flows. The ammonia vaporizer 2 evaporates the liquid ammonia X supplied from the liquid ammonia supply unit 3 and the heat transfer medium flowing through the heat exchange tube to produce ammonia gas Y.

[0017] A gas supply pipe 5 is connected to the ammonia vaporizer 2. The ammonia gas Y produced in the ammonia vaporizer 2 is sent to the destination via the gas supply pipe 5. The gas supply pipe 5 is connected to the top of the ammonia vaporizer 2.

[0018] The liquid ammonia supply unit 3 supplies liquid ammonia X stored in the low-temperature storage tank 100 to the ammonia vaporizer 2. As shown in Figure 1, the liquid ammonia supply unit 3 includes a discharge pump 3a located inside the low-temperature storage tank 100 and a supply pipe 3b connecting the discharge pump 3a to the ammonia vaporizer 2.

[0019] The discharge pump 3a is a pump that discharges liquid ammonia X from the low-temperature storage tank 100. The discharge pump 3a pressurizes the liquid ammonia X stored in the low-temperature storage tank 100 and sends it to the supply pipe 3b. Note that the discharge pump 3a does not necessarily have to be located inside the low-temperature storage tank 100. The discharge pump 3a may be installed outside the low-temperature storage tank 100.

[0020] The supply pipe 3b is connected to the discharge pump 3a at its upstream end and to the ammonia vaporizer 2 at its downstream end. The downstream end of the supply pipe 3b is branched into two, and connected to the upper and lower parts of the ammonia vaporizer 2, respectively. However, the downstream end of the supply pipe 3b does not necessarily have to be branched.

[0021] Furthermore, the liquid ammonia supply unit 3 includes a flow control valve 3c installed in the middle of the upstream portion of the supply pipe 3b. The liquid ammonia supply unit 3 also includes an on-off valve 3d installed in the middle of the downstream portion of the supply pipe 3b that connects to the upper part of the ammonia vaporizer 2, and another on-off valve 3d installed in the middle of the downstream portion of the supply pipe 3b that connects to the lower part of the ammonia vaporizer 2.

[0022] The liquid ammonia supply unit 3 adjusts the opening degree of the flow control valve 3c based on a command from, for example, a higher-level control unit. The liquid ammonia supply unit 3 can adjust the flow rate of liquid ammonia X supplied from the low-temperature storage tank 100 to the ammonia vaporizer 2.

[0023] The liquid ammonia extraction unit 4 is connected to the ammonia vaporizer 2 and extracts the liquid ammonia accumulated in the ammonia vaporizer 2. The liquid ammonia extraction unit 4 includes a drain pipe 4a, a liquid extraction pump 4b, a bypass pipe 4c (guide section), a flow meter 4d, a liquid level gauge 4e, a flow control valve 4f, an evaporator 4g, and an evaporator connecting pipe 4h.

[0024] The drainage pipe 4a is a pipe that extracts liquid ammonia X from the ammonia vaporizer 2. The drainage pipe 4a extracts the liquid ammonia X accumulated in the ammonia vaporizer 2 from the ammonia vaporizer 2. The liquid ammonia X that the drainage pipe 4a extracts from the ammonia vaporizer 2 (i.e., the liquid ammonia X accumulated in the ammonia vaporizer 2) has a higher water concentration than the liquid ammonia X stored in the low-temperature storage tank 100.

[0025] In this embodiment, the drain pipe 4a is connected to the ammonia vaporizer 2 and the evaporator 4g. The drain pipe 4a is connected to the ammonia vaporizer 2 at a position that can guide the liquid ammonia X accumulated inside the ammonia vaporizer 2 to the outside of the ammonia vaporizer 2. In this embodiment, the drain pipe 4a is connected to the bottom of the ammonia vaporizer 2. However, the drain pipe 4a may be connected to the ammonia vaporizer 2 at a position above the bottom of the ammonia vaporizer 2, as long as it is below the liquid level inside the ammonia vaporizer 2.

[0026] The drain pump 4b is installed in the middle of the drain pipe 4a. The drain pump 4b sucks in the liquid ammonia X that flows from the ammonia vaporizer 2 into the drain pipe 4a and discharges it toward the opposite side of the ammonia vaporizer 2. In other words, in this embodiment, the drain pump 4b sends the liquid ammonia X that flows from the ammonia vaporizer 2 into the drain pipe 4a toward the evaporator 4g.

[0027] The bypass pipe 4c is a pipe connected to the drain pipe 4a so as to bypass the drain pump 4b. The upstream end of the bypass pipe 4c is connected to the drain pipe 4a at a position upstream of the drain pump 4b. The downstream end of the bypass pipe 4c is also connected to the drain pipe 4a at a position downstream of the drain pump 4b. By flowing liquid ammonia X through the bypass pipe 4c, it is possible to flow the liquid ammonia X from the upstream end to the downstream end of the drain pipe 4a without passing through the drain pump 4b. The bypass pipe 4c is a guide for flowing liquid ammonia X into the drain pipe 4a when the drain pump 4b is stopped. If there is a passage inside the drain pump 4b through which liquid ammonia X can pass when the drain pump 4b is stopped, this passage can also be used as a guide. Alternatively, the passage inside the drain pump 4b and the bypass pipe 4c may be used in combination.

[0028] As shown in Figure 1, an on-off valve 4i is provided between the connection point between the drain pipe 4a and the upstream end of the bypass pipe 4c and the drain pump 4b. An on-off valve 4i is also provided in the bypass pipe 4c. By selecting the open or closed state of these on-off valves 4i, it is possible to choose whether the liquid ammonia X flowing from the ammonia vaporizer 2 into the drain pipe 4a passes through the drain pump 4b or through the bypass pipe 4c.

[0029] The flow meter 4d measures the flow rate of liquid ammonia X flowing through the drain pipe 4a and outputs a signal indicating the measurement result. The flow meter 4d is installed at an intermediate point in the drain pipe 4a. In this embodiment, the flow meter 4d is positioned downstream of the connection point between the drain pipe 4a and the downstream end of the bypass pipe 4c. Therefore, the flow meter 4d can also measure the flow rate of liquid ammonia X flowing through the bypass pipe 4c.

[0030] The liquid level gauge 4e is installed in the ammonia vaporizer 2 and detects the liquid level of the liquid ammonia X accumulated in the ammonia vaporizer 2, and outputs a signal indicating the detection result. The flow meter 4d and the liquid level gauge 4e are connected to the flow control valve 4f.

[0031] The flow control valve 4f is installed in the middle of the drain pipe 4a, downstream of the flow meter 4d. The flow control valve 4f adjusts the flow rate of liquid ammonia X extracted from the ammonia vaporizer 2 by the liquid ammonia extraction unit 4. The flow control valve 4f adjusts its opening degree based on the measurement results input from the flow meter 4d and the detection results input from the liquid level gauge 4e.

[0032] The evaporator 4g is connected to the downstream end of the drain pipe 4a. The evaporator 4g evaporates the liquid ammonia X supplied from the drain pipe 4a to ammonia gas Y. The evaporator 4g is at a higher temperature than, for example, the ammonia vaporizer 2, and evaporates the liquid ammonia X including the water contained in it.

[0033] The evaporator connection pipe 4h is a pipe that connects the evaporator 4g to the gas supply pipe 5. The evaporator connection pipe 4h supplies the ammonia gas Y generated in the evaporator 4g to the gas supply pipe 5. In this embodiment, the evaporator 4g is located below the ammonia vaporizer 2. More specifically, the evaporator 4g is located below the ammonia vaporizer 2 so that liquid ammonia X can move from the ammonia vaporizer 2 to the evaporator 4g via the bypass pipe 4c when the liquid extraction pump 4b is not being driven. In other words, in the ammonia vaporization equipment 1 of this embodiment, the liquid ammonia extraction section 4 can move liquid ammonia X from the ammonia vaporizer 2 to the evaporator 4g without using a device that forcibly flows the liquid, such as a pump.

[0034] The gas supply piping 5 is a pipe that connects the ammonia vaporizer 2 to the supply destination of ammonia gas Y. An ammonia gas heat exchanger 6 is installed in the middle of the gas supply piping 5. The ammonia gas heat exchanger 6 is a superheater that further raises the temperature of the ammonia gas Y discharged from the ammonia vaporizer 2, thereby evaporating the droplet-like liquid ammonia X contained in the ammonia gas Y. The ammonia gas heat exchanger 6 is located upstream of the connection point between the gas supply piping 5 and the evaporator connection piping 4h.

[0035] The flow control valve 4f and the two on-off valves 4i are connected to the control device 7. The control device 7 can control the opening degree of the flow control valve 4f and the open / closed state of the two on-off valves 4i. The control device 7 can also control the drain pump 4b. The control device 7 can drive or stop the drain pump 4b.

[0036] For example, the control device 7 changes the flow path of liquid ammonia X in the liquid ammonia extraction unit 4 based on the state of the supply destination (load). Specifically, when the load is stable, the control device 7 drives the extraction pump 4b and controls the on-off valve 4i so that the liquid ammonia X is pressurized by the extraction pump 4b before being supplied to the evaporator 4g. On the other hand, when the load is fluctuating beyond a predetermined range, the control device 7 stops the extraction pump 4b and controls the on-off valve 4i so that the liquid ammonia X flows through the bypass piping 4c.

[0037] For example, when the load is stable, the control device 7 opens the on-off valve 4i located between the connection point between the drain pipe 4a and the upstream end of the bypass pipe 4c and the drain pump 4b, and closes the on-off valve 4i located on the bypass pipe 4c. On the other hand, when the load is fluctuating beyond a predetermined range, the control device 7 closes the on-off valve 4i located between the connection point between the drain pipe 4a and the upstream end of the bypass pipe 4c and the drain pump 4b, and opens the on-off valve 4i located on the bypass pipe 4c.

[0038] In the ammonia vaporization equipment 1 of this embodiment, liquid ammonia X is supplied from the liquid ammonia supply unit 3 to the ammonia vaporizer 2. The liquid ammonia X supplied to the ammonia vaporizer 2 is vaporized in the ammonia vaporizer 2 to become ammonia gas Y. The ammonia gas Y is sent from the ammonia vaporizer 2 to the destination via the gas supply piping 5. The liquid ammonia X remaining in the ammonia gas Y is vaporized in the ammonia gas heat exchanger 6 located in the middle of the gas supply piping 5.

[0039] Furthermore, liquid ammonia X containing water accumulates in the ammonia vaporizer 2. The liquid ammonia X accumulated in the ammonia vaporizer 2 is extracted from the ammonia vaporizer 2 by the liquid ammonia extraction unit 4. When the liquid extraction pump 4b is running, the liquid ammonia X extracted from the ammonia vaporizer 2 is supplied to the evaporator 4g via the liquid extraction pump 4b, where it is evaporated to become ammonia gas Y. On the other hand, when the liquid extraction pump 4b is stopped, the liquid ammonia X extracted from the ammonia vaporizer 2 is supplied to the evaporator 4g via the bypass pipe 4c, where it is evaporated to become ammonia gas Y. The ammonia gas Y generated in the evaporator 4g is supplied to the gas supply pipe 5 via the evaporator connection pipe 4h.

[0040] In the ammonia vaporization equipment 1 of this embodiment, if the pressure in the ammonia vaporizer 2 fluctuates due to load fluctuations at the supply destination, liquid ammonia X can be supplied from the ammonia vaporizer 2 to the evaporator 4g without going through the liquid drain pump 4b. Therefore, according to the ammonia vaporization equipment 1 of this embodiment, cavitation and the like in the liquid drain pump 4b can be suppressed even when the load fluctuations are large.

[0041] The ammonia vaporization equipment 1 of this embodiment, as described above, comprises an ammonia vaporizer 2 and a liquid ammonia extraction unit 4. The ammonia vaporizer 2 vaporizes liquid ammonia X. The liquid ammonia extraction unit 4 extracts the liquid ammonia X accumulated in the ammonia vaporizer 2. The liquid ammonia extraction unit 4 also includes a drain pipe 4a, a liquid extraction pump 4b, and a bypass pipe 4c. The drain pipe 4a is connected to the ammonia vaporizer 2. The liquid extraction pump 4b is installed in the middle of the drain pipe 4a. The bypass pipe 4c is connected to the drain pipe 4a so as to bypass the liquid extraction pump 4b. The bypass pipe 4c allows liquid ammonia X to flow into the drain pipe 4a when the liquid extraction pump 4b is stopped.

[0042] According to the ammonia vaporization facility 1 of the present embodiment, the liquid ammonia extraction unit 4 includes a bypass pipe 4c that bypasses the liquid drainage pump 4b. Therefore, according to the ammonia vaporization facility 1 of the present embodiment, when the pressure in the liquid drainage pump 4b temporarily decreases due to load fluctuation or the like, the liquid ammonia X extracted from the ammonia vaporizer 2 can be caused to flow so as to bypass the liquid drainage pump 4b, whereby flashing of the liquid ammonia X can be suppressed. Therefore, the ammonia vaporization facility 1 of the present embodiment, which is a facility capable of extracting the liquid ammonia X accumulated in the ammonia vaporizer 2, can suppress the occurrence of cavitation in the liquid drainage pump 4b. Note that even when a flow path through which liquid ammonia X can pass while the liquid drainage pump 4b is stopped is provided inside the liquid drainage pump 4b, the liquid ammonia X extracted from the ammonia vaporizer 2 can be caused to flow in a state where the liquid drainage pump 4b is stopped, and similarly, the occurrence of cavitation in the liquid drainage pump 4b can be suppressed.

[0043] In addition, the ammonia vaporization facility 1 of the present embodiment includes a gas feed pipe 5 that guides ammonia gas Y generated in the ammonia vaporizer 2 to a supply destination. Further, the liquid ammonia extraction unit 4 includes an evaporator 4g and an evaporator connection pipe 4h. The evaporator 4g evaporates the liquid ammonia X supplied from the drainage pipe 4a. The evaporator connection pipe 4h connects the evaporator 4g and the gas feed pipe 5.

[0044] According to the ammonia vaporization facility 1 of the present embodiment, the liquid ammonia X extracted from the ammonia vaporizer 2 can be evaporated into ammonia gas Y. Further, the ammonia gas Y generated in the evaporator 4g can be guided to the gas feed pipe 5 via the evaporator connection pipe 4h and supplied to the supply destination. Therefore, the liquid ammonia X extracted from the ammonia vaporizer 2 can be effectively utilized.

[0045] Furthermore, according to the ammonia vaporization facility 1 of the present embodiment, water contained in the liquid ammonia X extracted from the ammonia vaporizer 2 can also be evaporated by the evaporator 4g. Further, the evaporated water can be supplied to a supply destination via the gas supply pipe 5. Therefore, the ammonia vaporization facility 1 of the present embodiment does not require separation of the water extracted from the ammonia vaporizer 2 from the liquid ammonia X and the ammonia gas Y for treatment.

[0046] Furthermore, in the ammonia vaporization facility 1 of the present embodiment, the evaporator 4g is disposed below the ammonia vaporizer 2. According to the ammonia vaporization facility 1 of the present embodiment, the liquid ammonia X can be flowed from the ammonia vaporization facility 1 to the evaporator 4g by utilizing gravity. Therefore, the ammonia vaporization facility 1 of the present embodiment can flow the liquid ammonia X from the ammonia vaporizer 2 to the evaporator 4g without using power even when the liquid draining pump 4b is stopped.

[0047] Figure 2 is a flow diagram showing a modified example of the ammonia vaporization facility 1 of the present embodiment. As shown in Figure 2, an orifice 8 (pressure reducing portion) may be provided at an intermediate position of the gas supply pipe 5. The orifice 8 is disposed between the ammonia vaporizer 2 and the ammonia gas heat exchanger 6, and reduces the pressure of the ammonia gas Y. That is, the orifice 8 is located at an intermediate position of the gas supply pipe 5, and is disposed upstream of the connection point between the evaporator connection pipe 4h and the gas supply pipe 5. By providing the orifice 8, the pressure on the downstream side of the orifice 8 is lower than that on the upstream side. Therefore, in the modified example of the ammonia vaporization facility 1 of the present embodiment, the pressure of the evaporator 4g can be reduced, and the liquid ammonia X can be easily flowed from the ammonia vaporizer 2 to the evaporator 4g. Note that, instead of the orifice 8, another pressure reducing portion such as a pressure reducing valve may be provided.

[0048] (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to Figure 3. In the description of the present embodiment, the description of the same parts as those in the first embodiment described above will be omitted or simplified.

[0049] Figure 3 is a schematic flow diagram showing the general configuration of the ammonia vaporization equipment 1A of this embodiment. As shown in Figure 3, in the ammonia vaporization equipment 1A of this embodiment, the drainage pipe 4a is connected to the low-temperature storage tank 100.

[0050] The low-temperature storage tank 100 is a tank that stores liquid ammonia X before it is supplied to the ammonia vaporizer 2. The liquid ammonia X in the low-temperature storage tank 100 is pressurized by the discharge pump 3a and supplied to the ammonia vaporizer 2. Therefore, the pressure of the liquid ammonia X in the ammonia vaporizer 2 is higher than the pressure of the liquid ammonia X in the low-temperature storage tank 100. For this reason, by connecting the drain pipe 4a to the low-temperature storage tank 100, the liquid ammonia X extracted from the ammonia vaporizer 2 can be returned to the low-temperature storage tank 100 without using the drain pump 4b. Furthermore, even when the drain pump 4b is used, it is possible to reduce the power used by the drain pump 4b.

[0051] Furthermore, in the ammonia vaporization equipment 1A of this embodiment, the liquid ammonia extraction unit 4 has a liquid ammonia heat exchanger 4j (cooling unit). The liquid ammonia heat exchanger 4j cools the liquid ammonia X supplied to the low-temperature storage tank 100 via the drain pipe 4a. In this embodiment, the liquid ammonia heat exchanger 4j causes heat exchange between the liquid ammonia X supplied to the ammonia vaporizer 2 via the supply pipe 3b and the liquid ammonia X supplied to the low-temperature storage tank 100 via the drain pipe 4a. In other words, the liquid ammonia heat exchanger 4j causes heat exchange between the liquid ammonia X before it is supplied to the ammonia vaporizer 2 and the liquid ammonia X flowing through the drain pipe 4a.

[0052] The liquid ammonia X supplied to the low-temperature storage tank 100 via the drain pipe 4a is cooled by the liquid ammonia heat exchanger 4j, thereby suppressing the generation of boil-off gas in the low-temperature storage tank 100. Furthermore, the liquid ammonia X is heated by the liquid ammonia heat exchanger 4j before being supplied to the ammonia vaporizer 2. This reduces the amount of energy required to vaporize the liquid ammonia X in the ammonia vaporizer 2. The drain pipe 4a may also be equipped with a pressure adjustment unit to regulate the pressure of the liquid ammonia X.

[0053] In the ammonia vaporization equipment 1A of this embodiment described above, the drain pipe 4a is connected to a low-pressure section where the pressure is lower than that of the ammonia vaporizer 2. According to the ammonia vaporization equipment 1A of this embodiment, the liquid ammonia X extracted from the ammonia vaporizer 2 can be returned to the low-temperature storage tank 100 without using a drain pump 4b. Furthermore, even when a drain pump 4b is used, it is possible to reduce the power required for the drain pump 4b.

[0054] Furthermore, in the ammonia vaporization equipment 1A of this embodiment, the low-pressure section is a low-temperature storage tank 100 that stores liquid ammonia X before it is supplied to the ammonia vaporizer 2. Therefore, there is no need to provide a separate low-pressure section from the low-temperature storage tank 100, which helps to prevent the structure of the ammonia vaporization equipment 1A of this embodiment from becoming overly complex.

[0055] Furthermore, in the ammonia vaporization equipment 1A of this embodiment, the liquid ammonia extraction section 4 is equipped with a liquid ammonia heat exchanger 4j. The liquid ammonia heat exchanger 4j is installed in the middle of the drainage pipe 4a. The liquid ammonia heat exchanger 4j also cools the liquid ammonia X supplied to the low-temperature storage tank 100.

[0056] According to the ammonia vaporization equipment 1A of this embodiment, the liquid ammonia X supplied to the low-temperature storage tank 100 via the drain pipe 4a is cooled, thereby suppressing the generation of boil-off gas in the low-temperature storage tank 100.

[0057] Furthermore, in the ammonia vaporization equipment 1A of this embodiment, the liquid ammonia heat exchanger 4j exchanges heat between the liquid ammonia X before it is supplied to the ammonia vaporizer 2 and the liquid ammonia X flowing through the drain pipe 4a.

[0058] According to the ammonia vaporization equipment 1A of this embodiment, the liquid ammonia X is heated before being supplied to the ammonia vaporizer 2, making it possible to reduce the amount of energy required to vaporize the liquid ammonia X in the ammonia vaporizer 2.

[0059] Alternatively, a separate cooling unit may be provided in addition to the liquid ammonia heat exchanger 4j to cool the liquid ammonia X flowing through the drain pipe 4a.

[0060] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to the above embodiments. The shapes and combinations of the constituent members shown in the above embodiments are examples, and can be modified in various ways based on design requirements, etc., without departing from the spirit of the present invention.

[0061] Furthermore, the above embodiments can also be described, for example, as shown in the following appendix.

[0062] (Note 1) An ammonia vaporization apparatus comprising: an ammonia vaporizer for vaporizing liquid ammonia; and a liquid ammonia extraction unit for extracting liquid ammonia accumulated in the ammonia vaporizer, wherein the liquid ammonia extraction unit comprises: a drain pipe connected to the ammonia vaporizer; a drain pump provided at an intermediate point in the drain pipe; and a guide unit for flowing the liquid ammonia into the drain pipe when the drain pump is stopped.

[0063] (Note 2) The ammonia vaporization equipment according to Note 1, comprising a gas supply pipe for guiding the ammonia gas generated in the ammonia vaporizer to a supply destination, wherein the liquid ammonia extraction section comprises an evaporator for evaporating the liquid ammonia supplied from the drain pipe, and an evaporator connecting pipe for connecting the evaporator and the gas supply pipe.

[0064] (Note 3) The ammonia vaporization equipment described in Note 2, wherein the evaporator is located below the ammonia vaporizer.

[0065] (Note 4) The ammonia vaporization equipment according to Note 2 or 3, comprising a pressure reducing section provided in the middle of the gas supply piping for reducing the pressure of the ammonia gas, wherein the pressure reducing section is located upstream of the connection point between the evaporator connection piping and the gas supply piping.

[0066] (Note 5) The ammonia vaporization equipment described in any one of Notes 1 to 4, wherein the drainage piping is connected to a low-pressure section where the pressure is lower than that of the ammonia vaporizer.

[0067] (Note 6) The ammonia vaporization equipment as described in Note 5, wherein the low-pressure section is a tank for storing liquid ammonia before it is supplied to the ammonia vaporizer.

[0068] (Note 7) The ammonia vaporization apparatus according to Note 5 or 6, wherein the liquid ammonia extraction section is provided in the middle of the drainage piping and has a cooling section for cooling the liquid ammonia supplied to the low-pressure section.

[0069] (Note 8) The ammonia vaporization equipment as described in Note 7, wherein the cooling unit is a heat exchanger that exchanges heat between the liquid ammonia before it is supplied to the ammonia vaporizer and the liquid ammonia flowing through the drain pipe.

[0070] According to the present invention, in an ammonia vaporization system capable of extracting liquid ammonia accumulated in an ammonia vaporizer, the generation of cavitation in the liquid extraction pump can be suppressed.

[0071] 1...Ammonia vaporization equipment, 1A...Ammonia vaporization equipment, 2...Ammonia vaporizer, 3...Liquid ammonia supply section, 3a...Discharge pump, 3b...Supply piping, 3c...Flow control valve, 3d...On / off valve, 4...Liquid ammonia extraction section, 4a...Drainage piping, 4b...Liquid extraction pump, 4c...Bypass piping (guide section), 4d...Flow meter, 4e...Liquid level gauge, 4f...Flow control valve, 4g...Evaporator, 4h...Evaporator connection piping, 4i...On / off valve, 4j...Liquid ammonia heat exchanger (cooling section, heat exchanger), 5...Gas supply piping, 6...Ammonia gas heat exchanger, 7...Control device, 8...Orifice (pressure reduction section), 100...Low-temperature storage tank (low-pressure section, tank), X...Liquid ammonia, Y...Ammonia gas

Claims

1. An ammonia vaporization apparatus comprising: an ammonia vaporizer for vaporizing liquid ammonia; and a liquid ammonia extraction unit for extracting the liquid ammonia accumulated in the ammonia vaporizer, wherein the liquid ammonia extraction unit comprises: a drain pipe connected to the ammonia vaporizer; a drain pump provided at an intermediate point in the drain pipe; and a guide unit for flowing the liquid ammonia into the drain pipe when the drain pump is stopped.

2. The ammonia vaporization apparatus according to claim 1, comprising a gas supply pipe for guiding the ammonia gas generated in the ammonia vaporizer to a supply destination, wherein the liquid ammonia extraction unit comprises an evaporator for evaporating the liquid ammonia supplied from the drain pipe, and an evaporator connecting pipe for connecting the evaporator and the gas supply pipe.

3. The ammonia vaporization apparatus according to claim 2, wherein the evaporator is located below the ammonia vaporizer.

4. The ammonia vaporization apparatus according to claim 2 or 3, comprising a pressure reducing section provided in the middle of the gas supply piping for reducing the pressure of the ammonia gas, wherein the pressure reducing section is located upstream of the connection point between the evaporator connection piping and the gas supply piping.

5. The ammonia vaporization equipment according to any one of claims 1 to 3, wherein the drainage piping is connected to a low-pressure section where the pressure is lower than that of the ammonia vaporizer.

6. The ammonia vaporization apparatus according to claim 5, wherein the low-pressure section is a tank for storing liquid ammonia before supplying it to the ammonia vaporizer.

7. The ammonia vaporization apparatus according to claim 5, wherein the liquid ammonia extraction section is provided in the middle of the drainage piping and has a cooling section for cooling the liquid ammonia supplied to the low-pressure section.

8. The ammonia vaporization apparatus according to claim 7, wherein the cooling unit is a heat exchanger that exchanges heat between the liquid ammonia before it is supplied to the ammonia vaporizer and the liquid ammonia flowing through the drain pipe.

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