WO2024135407A1 - Ammonia vaporizer - Google Patents

Abstract

An ammonia vaporizer (1) comprises: a shell (20) into which liquid ammonia (100) is introduced; a plurality of heat transfer tubes (23) that are disposed on the interior of the shell (20) and convey a heat-transfer medium; and a liquid ammonia extraction unit (40) that extracts the liquid ammonia (100) from the middle section of the shell (20) in the height direction.

Description

Ammonia Vaporizer

The present invention relates to an ammonia vaporizer.
This application claims priority based on Japanese Patent Application No. 2022-205752, filed on December 22, 2022, the contents of which are incorporated herein by reference.

Patent Document 1 below discloses a vaporizer that vaporizes liquefied ammonia, which contains ammonia as the main component and water as a high-boiling point component having a boiling point higher than that of the main component. This vaporizer includes a shell, a supply unit, a plurality of heat transfer tubes, an outlet unit, a liquid outlet unit, and a heater. The supply unit supplies liquefied gas into the shell. The plurality of heat transfer tubes are arranged in the shell, and a first heating fluid having a temperature that vaporizes the main component of the liquefied gas is introduced into the shell. The outlet unit discharges the main component vaporized in the shell from the shell. The liquid outlet unit is arranged at the bottom of the shell, and discharges the liquefied gas accumulated in the shell from the shell. The heater vaporizes the main component contained in the liquefied gas discharged from the shell through the liquid outlet unit by heat exchange with the second heating fluid.

Japanese Patent Application Publication No. 2022-6152

When the ammonia (main component, low boiling point component) vaporizes, the liquid ammonia becomes more concentrated with water (high boiling point component), and because its boiling point is higher, it tends to accumulate in the upper part of the liquid phase when the temperature increases. For this reason, even if the liquid ammonia that has accumulated in the shell is discharged from the bottom of the shell as in the above-mentioned conventional technology, there is a possibility that the liquid ammonia with a high water concentration cannot be efficiently discharged from inside the shell.

The present invention was made in consideration of the above circumstances, and aims to provide an ammonia vaporizer that can efficiently discharge liquid ammonia, which has a high water concentration due to the vaporization of ammonia, from within the shell.

The ammonia vaporizer according to the first aspect of the present invention comprises a shell into which liquid ammonia is introduced, a plurality of heat transfer tubes installed inside the shell and through which a heat transfer medium flows, and a liquid ammonia extraction section that extracts the liquid ammonia from the middle of the shell in the height direction.

In a second aspect of the present invention, the ammonia vaporizer of the first aspect may further include a mixer that mixes the liquid ammonia extracted from the liquid ammonia extraction section with the ammonia gas that has been vaporized inside the shell and discharged to the outside of the shell, and a heater that vaporizes the mixed fluid that has passed through the mixer.

In addition, in a third aspect of the present invention, in the ammonia vaporizer of the first or second aspect, the intermediate portion may be included within the range in the height direction in which the plurality of heat transfer tubes are arranged.

In a fourth aspect of the present invention, in the ammonia vaporizer of any one of the first to third aspects, the liquid ammonia outlet may include a first outlet and a second outlet, the first outlet being provided at a first height in the intermediate section, and the second outlet being provided at a second height in the intermediate section that is different from the first height.

In addition, in a fifth aspect of the present invention, the ammonia vaporizer of the fourth aspect may be provided with a first opening/closing device that opens and closes a flow path communicating with the first outlet, and a second opening/closing device that opens and closes a flow path communicating with the second outlet.

In a sixth aspect of the present invention, in the ammonia vaporizer of any one of the first to fifth aspects, the heat medium may be seawater.

According to one aspect of the present invention, liquid ammonia with a high water concentration due to vaporization of ammonia can be efficiently discharged from within the shell.

FIG. 1 is an overall configuration diagram of an ammonia vaporizer according to an embodiment. FIG. 2 is an internal configuration diagram of a vaporizer body according to one embodiment. 3 is a cross-sectional view taken along line III-III shown in FIG. 2. 1 is a graph showing the relationship between the boiling point/dew point of liquid ammonia and pressure.

Below, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an overall configuration diagram of an ammonia vaporizer 1 according to one embodiment.
The ammonia vaporizer 1 vaporizes liquid ammonia 100 supplied from a low-temperature storage tank 2, and supplies the ammonia gas to a supply destination (e.g., a boiler of a thermal power plant). The low-temperature storage tank 2 stores liquid ammonia 100 containing, for example, about 0.5 wt % water (a high boiling point component).

The low-temperature storage tank 2 is, for example, a large, double-shelled, above-ground low-temperature tank with a total height of about 50 meters. In the low-temperature storage tank 2, a cold insulation material such as granular perlite is filled between an inner tank and an outer tank (not shown). The low-temperature storage tank 2 may also be an underground low-temperature tank. The low-temperature storage tank 2 stores liquid ammonia 100 transferred from an ammonia tanker via an receiving pipe (not shown). The storage temperature of the liquid ammonia 100 is, for example, about -33°C to -34°C.

The ammonia vaporizer 1 comprises a vaporizer body 10 and a heater 11. The vaporizer body 10 is connected to the low-temperature storage tank 2 via a liquid ammonia supply flow path 3. The liquid ammonia supply flow path 3 supplies liquid ammonia 100 from the low-temperature storage tank 2 to the vaporizer body 10. The liquid ammonia supply flow path 3 is provided with a valve 3a for opening and closing the flow path, a pump (not shown), and the like.

The heater 11 is connected to the vaporizer body 10 via an ammonia gas outlet flow path 12. The ammonia gas outlet flow path 12 supplies the ammonia gas vaporized in the vaporizer body 10 to the heater 11. The heater 11 is also connected to a supply destination (not shown) via an ammonia gas supply flow path 13. The ammonia gas supply flow path 13 supplies the ammonia gas heated to a predetermined temperature by the heater 11 to the supply destination.

The vaporizer body 10 is connected to a first heat medium supply passage 14 and a first heat medium discharge passage 15. The first heat medium supply passage 14 supplies the first heat medium that vaporizes the liquid ammonia 100 to the vaporizer body 10. In this embodiment, the first heat medium is seawater 200. The first heat medium supply passage 14 is provided with a pump 14a that pumps up the seawater 200, a valve (not shown), and the like.

The first heat medium discharge flow path 15 discharges the seawater 200, which has been cooled by heat exchange with the liquid ammonia 100 inside the vaporizer body 10, into the sea. The first heat medium discharge flow path 15 is provided with valves, pumps, etc. (not shown). Note that the first heat medium is not limited to seawater 200, and depending on the installation location of the ammonia vaporizer 1, water from a river, lake, etc. may be used instead of seawater 200.

The heater 11 is connected to a second heat medium supply flow path 16 and a second heat medium discharge flow path 17. The second heat medium supply flow path 16 supplies the heater 11 with a second heat medium that heats the ammonia gas. In this embodiment, the second heat medium is, for example, steam generated in a boiler to which the second heat medium is supplied. The second heat medium supply flow path 16 is provided with a valve or the like (not shown).

The second heat medium discharge flow path 17 discharges the condensate that has condensed by heat exchange with the ammonia gas inside the heater 11. The second heat medium discharge flow path 17 is provided with a valve, etc. (not shown). The second heat medium discharge flow path 17 is connected to a cooler (not shown). The cooler recovers heat from the condensate that has exchanged heat with the ammonia gas, cools the condensate, and transports the condensate to a specified location.

A bottom extraction flow passage 18 is connected to the vaporizer body 10. The bottom extraction flow passage 18 extracts liquid ammonia 100 from the bottom of the vaporizer body 10. The bottom extraction flow passage 18 is provided with a valve 18a for opening and closing the flow passage, and a pump (not shown), etc.

Also, an intermediate extraction flow passage 19 is connected to the vaporizer body 10. The intermediate extraction flow passage 19 extracts liquid ammonia 100 with a high concentration of water (high boiling point component) from the intermediate part in the height direction of the vaporizer body 10. The intermediate extraction flow passage 19 is provided with valves 19a to 19c that open and close the flow passage, and a pump (not shown) that supplies the extracted liquid ammonia 100 (with a high water concentration) to the mixer 50 described below.

The mixer 50 mixes the ammonia gas discharged from the vaporizer body 10 with the liquid ammonia 100 extracted from the intermediate extraction flow path 19. The mixer 50 forms a mixed fluid, for example, by spraying liquid ammonia 100 with a high water concentration onto the ammonia gas flowing through the ammonia gas discharge flow path 12. The heater 11 raises the temperature of the mixed fluid that has passed through the mixer 50, completely vaporizing it.

FIG. 2 is a diagram showing the internal configuration of the vaporizer body 10 according to one embodiment.
As shown in Fig. 2, the vaporizer body 10 includes a shell 20, tube sheets 21 and 22, and a plurality of heat transfer tubes 23. The shell 20 is formed in a cylindrical shape extending in the horizontal direction. The tube sheets 21 and 22 support the plurality of heat transfer tubes 23 and divide the inside of the shell 20 into three spaces. Note that a plurality of baffle plates (not shown) may be provided between the tube sheets 21 and 22. In this case, the baffle plates do not divide the space inside the shell 20.

A first heat medium inlet 10A, a first heat medium outlet 10B, and a liquid ammonia vaporization chamber 10C are formed within the shell 20. The space between the first heat medium inlet 10A and the liquid ammonia vaporization chamber 10C is partitioned by a tube plate 21. The space between the liquid ammonia vaporization chamber 10C and the first heat medium outlet 10B is partitioned by a tube plate 22.

The tube plate 21 supports the first ends of the heat transfer tubes 23. The openings at the first ends of the heat transfer tubes 23 are connected to the first heat medium inlet section 10A. The tube plate 22 supports the second ends of the heat transfer tubes 23. The openings at the second ends of the heat transfer tubes 23 are connected to the first heat medium outlet section 10B. The multiple heat transfer tubes 23 are supported in parallel in the horizontal direction by the tube plates 21 and 22 and a baffle plate (not shown).

The shell 20 is formed with a first heat medium supply port 24 that communicates with the first heat medium inlet 10A. The first heat medium supply passage 14 described above is connected to the first heat medium supply port 24. The shell 20 is also formed with a first heat medium discharge port 25 that communicates with the first heat medium outlet 10B. The first heat medium discharge passage 15 described above is connected to the first heat medium discharge port 25.

The first heat medium (seawater 200) supplied from the first heat medium supply port 24 to the first heat medium inlet portion 10A exchanges heat with the liquid ammonia 100 in the liquid ammonia vaporization chamber 10C while passing through the heat transfer tubes 23, and flows out to the first heat medium outlet portion 10B. The first heat medium that flows out to the first heat medium outlet portion 10B is discharged from the first heat medium discharge port 25 through the first heat medium discharge flow path 15 to the outside of the shell 20. Note that the first heat medium supply port 24 and the first heat medium discharge port 25 may be provided on the side wall portion of the shell 20, or on the bottom or top of the shell 20, as long as the function of supplying and discharging the first heat medium can be ensured.

The upper part of the shell 20 is provided with an ammonia gas outlet 26 and a liquid ammonia supply port 27. The ammonia gas outlet 26 and the liquid ammonia supply port 27 are connected to the liquid ammonia vaporization chamber 10C. The liquid ammonia supply port 27 is connected to the liquid ammonia supply flow path 3 described above. The liquid ammonia supply port 27 is located in the center of the shell 20 in the longitudinal direction. The liquid ammonia supply port 27 is connected to a distributor 30 located inside the shell 20.

The distributor 30 is located above the heat transfer tubes 23 and extends parallel to the heat transfer tubes 23. The distributor 30 distributes the liquid ammonia 100 supplied from the liquid ammonia supply port 27 in the longitudinal direction of the shell 20. Examples of the distributor 30 include pipes or trays with numerous holes or notches formed therein. A pair of ammonia gas outlets 26 are provided on either side of the liquid ammonia supply port 27 at positions that do not overlap with the distributor 30 in a plan view.

The pair of ammonia gas outlets 26 includes a first ammonia gas outlet 26a disposed on the first heat medium inlet 10A (tube plate 21) side and a second ammonia gas outlet 26b disposed on the first heat medium outlet 10B (tube plate 22) side. The first ammonia gas outlet 26a is connected to the first branch pipe 12a of the ammonia gas outlet flow passage 12. The second ammonia gas outlet 26b is connected to the second branch pipe 12b of the ammonia gas outlet flow passage 12. The first branch pipe 12a and the second branch pipe 12b join together upstream (nearby) of the mixer 50 shown in FIG. 1.

A drain collection section 28 is provided at the bottom of the shell 20 so as to protrude downward. The drain collection section 28 is connected to the liquid ammonia vaporization chamber 10C. The drain collection section 28 is connected to the bottom extraction flow path 18 described above.

A liquid ammonia extraction section 40 that extracts the liquid ammonia 100 in the liquid ammonia vaporization chamber 10C is provided in the middle of the height of the shell 20. The liquid ammonia extraction section 40 has a first extraction outlet 41 provided at a first height and a second extraction outlet 42 provided at a second height different from the first height. The first extraction outlet 41 and the second extraction outlet 42 are disposed at different positions from each other in the longitudinal direction (horizontal direction) of the shell 20.

FIG. 3 is a cross-sectional view taken along line III-III shown in FIG.
3, the liquid ammonia withdrawal section 40 is provided in the middle part in the height direction of the shell 20. The middle part in the height direction of the shell 20 refers to a part of the shell 20 excluding the upper part of the shell 20 where the liquid ammonia supply port 27 is provided and the bottom part of the shell 20 where the drain recovery section 28 is connected.

The intermediate portion in the height direction of the shell 20 where the liquid ammonia extraction section 40 is provided is included in the range A in the height direction in which the multiple heat transfer tubes 23 are arranged. Specifically, the first height at which the first outlet 41 is provided is the same height as the center position C1 of the range A in which the multiple heat transfer tubes 23 are arranged. In addition, the second height at which the second outlet 42 is provided is lower than the first height, and is 1/4 the height from the bottom of the range A in which the multiple heat transfer tubes 23 are arranged. In addition, the first outlet 41 and the second outlet 42 are located below the center position C2 of the shell 20.

The first outlet 41 is connected to the first communication flow path 19A of the intermediate outlet flow path 19. The first communication flow path 19A is provided with a valve 19a that opens and closes the flow path. The second outlet 42 is connected to the second communication flow path 19B of the intermediate outlet flow path 19. The second communication flow path 19B is provided with a valve 19b that opens and closes the flow path. The first communication flow path 19A and the first communication flow path 19A join upstream of a pump (not shown) provided in the intermediate outlet flow path 19.

Either valve 19a or valve 19b is open when ammonia vaporizer 1 is in operation. A level gauge (not shown) that measures the liquid level of liquid ammonia 100 in liquid ammonia vaporization chamber 10C is connected to shell 20. Based on the level gauge, an operator opens valve 19a or valve 19b that corresponds to the liquid level of liquid ammonia 100, and extracts liquid ammonia 100 from the upper liquid phase. Note that a control device may be provided that automatically opens and closes valves 19a and 19b based on the measurement results of the level gauge.

Fig. 4 is a graph showing the relationship between the boiling point/dew point and pressure of liquid ammonia 100. In Fig. 4, the vertical axis represents the boiling point/dew point in units of °C. In Fig. 4, the horizontal axis represents the pressure in units of kPaG based on atmospheric pressure.
As shown in FIG. 4, the temperature of the seawater 200 varies between, for example, 17° C. in winter and 35° C. in summer.

If the inlet pressure of the vaporizer body 10 is 400 kPaG and the connecting pressure with the boiler is 350 kPaG, the temperature of the liquid ammonia 100 will be between the boiling point curve and the dew point curve in both winter and summer, and the liquid ammonia 100 will be in a gas-liquid mixed phase state. In other words, when seawater 200 is used as the first heat medium, a portion of the liquid ammonia 100 will not vaporize within the vaporizer body 10, and the concentration of water (high boiling point component) will gradually increase due to the vaporization of ammonia (main component, low boiling point component).

Liquid ammonia 100 with a high concentration of water (high boiling point component) has a high boiling point and is therefore difficult to vaporize. For this reason, it is desirable to discharge liquid ammonia 100 with a high water concentration from within the shell 20. Liquid ammonia 100 with a high water concentration and high boiling point is more likely to remain in the upper part of the liquid phase (near the liquid surface) shown in Figure 2 when the temperature becomes high. Therefore, as shown in Figures 2 and 3, by providing liquid ammonia extraction section 40 at the middle part of the shell 20 in the height direction rather than at the bottom of the shell 20, liquid ammonia 100 with a high water concentration can be efficiently discharged from within the shell 20.

The liquid ammonia 100 discharged from the shell 20 contains about 5 wt% water (high boiling point component). As shown in FIG. 1, the liquid ammonia 100 passes through the intermediate extraction flow path 19, is pressurized by a pump (not shown), and is then supplied to the mixer 50. The mixer 50 sprays the liquid ammonia 100, which has a high water concentration, into the ammonia gas flowing through the ammonia gas discharge flow path 12 to generate a mixed fluid. The heater 11 completely vaporizes the mixed fluid that has passed through the mixer 50 and supplies it to the destination.

As described above, the ammonia vaporizer 1 according to this embodiment includes a shell 20 into which liquid ammonia 100 is introduced, a plurality of heat transfer tubes 23 installed inside the shell 20 and through which a heat medium flows, and a liquid ammonia extraction section 40 that extracts the liquid ammonia 100 from the middle of the height of the shell 20. With this configuration, the liquid ammonia 100, which has a high water concentration due to the evaporation of ammonia, can be efficiently discharged from inside the shell 20.

In addition, this embodiment includes a mixer 50 that mixes the liquid ammonia 100 extracted from the liquid ammonia extraction section 40 with the ammonia gas that has been vaporized inside the shell 20 and discharged to the outside of the shell 20, and a heater 11 that vaporizes the mixed fluid that has passed through the mixer 50. With this configuration, the liquid ammonia 100 that has been discharged from the shell 20 and has a high water concentration can be vaporized and supplied to the supply destination.

In addition, in this embodiment, the intermediate portion where the liquid ammonia extraction section 40 is provided is included within the range A in the height direction in which the multiple heat transfer tubes 23 are arranged. This configuration makes it easier to extract liquid ammonia 100 with a high water concentration from the upper part of the liquid phase of liquid ammonia 100.

In addition, in this embodiment, the liquid ammonia extraction section 40 includes a first outlet 41 provided at a first height in the middle section, and a second outlet 42 provided at a second height different from the first height in the middle section. With this configuration, liquid ammonia 100 with a high water concentration can be extracted from two locations at different heights within the shell 20.

In addition, this embodiment includes a valve 19a (first opening/closing device) that opens and closes a first communication flow path 19A (flow path) that communicates with the first outlet 41, and a valve 19b (second opening/closing device) that opens and closes a second communication flow path 19B (flow path) that communicates with the second outlet 42. With this configuration, the extraction position of the liquid ammonia 100 can be changed depending on the water level of the liquid ammonia 100 in the shell 20.

In addition, in this embodiment, the first heat medium (heat medium) is seawater 200. With this configuration, the first heat medium that vaporizes the liquid ammonia 100 can be secured in large quantities at low cost.

Although preferred embodiments of the present invention have been described and illustrated above, it should be understood that these are illustrative of the present invention and should not be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the present invention should not be considered as limited by the foregoing description, but rather by the scope of the appended claims.

According to one aspect of the present invention, liquid ammonia with a high water concentration due to vaporization of ammonia can be efficiently discharged from within the shell.

1...ammonia vaporizer, 2...low-temperature storage tank, 3...liquid ammonia supply flow path, 3a...valve, 10...vaporizer body, 10A...first heat medium inlet section, 10B...first heat medium outlet section, 10C...liquid ammonia vaporization chamber, 11...heater, 12...ammonia gas discharge flow path, 12a...first branch pipe, 12b...second branch pipe, 13...ammonia gas supply flow path, 14...first heat medium supply flow path, 14a...pump, 15...first heat medium discharge flow path, 16...second heat medium supply flow path, 17...second heat medium discharge flow path, 18...bottom extraction flow path, 18a...valve, 19...middle extraction flow path, 19a...valve (first opening/closing device), 19A...first Communication flow path, 19b... valve (second opening/closing device), 19B... second communication flow path, 19c... valve, 20... shell, 21... tube plate, 22... tube plate, 23... heat transfer tube, 24... first heat medium supply port, 25... first heat medium discharge port, 26... ammonia gas outlet, 26a... first ammonia gas outlet, 26b... second ammonia gas outlet, 27... liquid ammonia supply port, 28... drain recovery section, 30... distributor, 40... liquid ammonia discharge section, 41... first outlet, 42... second outlet, 50... mixer, 100... liquid ammonia, 200... seawater (heat medium), A... range, C1... center position, C2... center position

Claims (6)

a shell into which liquid ammonia is introduced;
A plurality of heat transfer tubes are installed inside the shell and through which a heat transfer medium flows;
A liquid ammonia discharge section that discharges the liquid ammonia from a middle part in a height direction of the shell.
Ammonia vaporizer. a mixer that mixes the liquid ammonia extracted from the liquid ammonia extraction part with the ammonia gas that has been vaporized inside the shell and discharged to the outside of the shell;
A heater that vaporizes the mixed fluid that has passed through the mixer.
2. The ammonia vaporizer of claim 1. The intermediate portion is included in a range in the height direction in which the plurality of heat transfer tubes are arranged.
2. The ammonia vaporizer of claim 1. the liquid ammonia withdrawal section includes a first withdrawal outlet and a second withdrawal outlet,
The first outlet is provided at a first height in the intermediate portion,
The second outlet is provided at a second height different from the first height in the intermediate portion.
2. The ammonia vaporizer of claim 1. a first opening/closing device that opens and closes a flow path that communicates with the first outlet;
A second opening/closing device that opens and closes a flow path communicating with the second outlet.
5. The ammonia vaporizer of claim 4. The heat medium is seawater.
The ammonia vaporizer according to any one of claims 1 to 5.

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