JP7426219B2 - water production system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fresh water production system.

BACKGROUND ART Conventionally, as a water generation system for producing distilled water from seawater on a ship, the one described in Patent Document 1 is known. This fresh water production system includes an evaporation section that evaporates seawater, and a condensation section that condenses steam generated in the evaporation section to produce distilled water.

Japanese Patent Application Publication No. 2017-192942

Distilled water produced from seawater is used for various purposes in ships, such as drinking water, domestic water, and boiler supply water. If the amount of fresh water used on a ship exceeds the production capacity of the water production system, it is necessary to receive fresh water from outside the ship. However, if significant equipment changes are made to the mechanism of a conventional water production system in an attempt to improve water production efficiency, there is a possibility that costs will increase on the contrary.

The present invention has been made to solve these problems, and aims to provide a water generation system that can improve the efficiency of producing distilled water without significantly changing the mechanism of the conventional water generation system. purpose.

The water production system of the present invention is a water production system for producing distilled water from seawater on a ship, and includes an evaporation section that evaporates seawater and a condensation section that condenses steam generated in the evaporation section to produce distilled water. , a channel for supplying seawater to the evaporation section after passing through the condensation section, and a flow path for supplying seawater to the evaporation section after passing through the condensation section, and a flow path for supplying the seawater to the evaporation section using a heat transfer medium whose temperature has been lowered by heating the liquefied gas fuel. A cooling section that cools the steam.

The fresh water production system of the present invention includes an evaporation section that evaporates seawater, a condensation section that condenses the steam generated in the evaporation section to produce distilled water, and a condensation section that circulates the seawater after passing through the condensation section. , a flow path for supplying seawater to the evaporation section. With such a configuration, the seawater cools the steam generated in the evaporation section by passing through the condensation section via the flow path before being supplied to the evaporation section. Thereby, the steam cooled in the condensing section is condensed and recovered as distilled water. From the viewpoint of environmental protection, for example, liquefied gas fuel is sometimes used as fuel for ships in order to reduce SOx _, NOx _{, and CO2} emissions. When using the liquefied gas fuel, the liquefied gas fuel is heated using a heat medium. After heating the liquefied gas fuel, the temperature of the heat medium decreases to a low temperature. Therefore, in order to effectively utilize the cooling power of the heating medium whose temperature has been lowered by heating the liquefied gas fuel, the fresh water generation system has a cooling section that cools the steam in the condensing section using the heating medium. Be prepared. This makes it easier for the cooling section to condense steam in the condensing section. As described above, the water generation system can improve the efficiency of producing distilled water without significantly changing the mechanism of the conventional water generation system.

The cooling section may cool the steam in the condensing section by cooling the seawater in the channel upstream of the condensing section. In this case, since it is only necessary to add a cooling section to the flow path upstream of the condensate section, the structure for cooling is can be made simple.

The fresh water production system may further include a heating section that heats seawater flowing between the condensing section and the evaporation section using seawater upstream of the condensing section in the flow path. In this case, the heating section can heat the seawater after passing through the condensing section before being supplied to the evaporation section. Thereby, the evaporation efficiency in the evaporation section can be improved.

According to the present invention, it is possible to provide a water generation system that can improve distilled water production efficiency without significantly changing the mechanism of a conventional water generation system.

1 is a schematic side view showing an example of a ship to which a fresh water production system according to an embodiment of the present invention is applied. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows the system structure of the fresh water generation system based on this embodiment. FIG. 2 is a schematic configuration diagram showing in detail the relationship between the liquefied gas fuel system and the freshwater generator. FIG. 7 is a schematic configuration diagram showing in detail the relationship between a liquefied gas fuel system and a fresh water generating device in a fresh water generating system according to a modification.

Hereinafter, preferred embodiments of the fresh water production system of the present invention will be described with reference to the drawings. In the following explanation, the words "front" and "rear" correspond to the direction of movement of the ship, the word "lateral" corresponds to the left and right (width) direction of the ship, and the words "above" and "back" correspond to the direction of movement of the ship. The word "bottom" corresponds to the vertical direction of the hull.

FIG. 1 is a schematic side view showing an example of a ship to which a fresh water production system 100 according to an embodiment of the present invention is applied. The ship 1 is, for example, an oil tanker. Although the ship 1 is not limited to an oil tanker, the system will be explained using the structure of an oil tanker in the subsequent drawings. A ship 1 to which the fresh water production system 100 is applied is a ship that uses liquefied gas fuel as fuel. As the liquefied gas fuel, for example, LNG (liquefied natural gas) and LPG (liquefied petroleum gas) are used. The ship 1 may use only liquefied gas fuel as fuel, or may use both liquefied gas fuel and liquid fuel.

The ship 1 includes a hull 11 and a propulsion device 12, as shown in FIG. The hull 11 has a bow section 2, a stern section 3, an engine room 4, a pump room 5, and a cargo compartment 6. The bow section 2 is located on the front side of the hull 11. The stern section 3 is located on the rear side of the hull 11. The bow portion 2 has a shape designed to reduce wave-making resistance, for example, in a fully loaded draft state. The propulsion device 12 propels the hull 11, and uses, for example, a screw shaft. The propulsion device 12 is installed below the waterline (the water surface of the seawater SW) in the stern section 3. Further, below the waterline in the stern section 3, a rudder 15 is installed for adjusting the propulsion direction.

The engine room 4 is provided at a position adjacent to the bow side of the stern section 3. The engine room 4 is a compartment in which an engine 16 for providing driving force to the propulsion device 12 is disposed. The pump room 5 is provided at a position adjacent to the engine room 4 on the bow side. The pump chamber 5 is a section where pumps and the like are arranged. The cargo compartment 6 is provided between the bow section 2 and the pump room 5. The cargo hold 6 is a compartment for accommodating petroleum cargo. The cargo compartment 6 is divided into a cargo oil tank and a ballast tank by adopting a double hull structure. The cargo oil tank loads cargo carried by the vessel 1. The ballast tank stores ballast water in an amount corresponding to the weight of the petroleum cargo loaded in the cargo oil tank.

A deck 19 is provided at the top of the hull 11. A liquefied gas fuel tank 21 for storing liquefied gas fuel is provided on the deck 19. The liquefied gas fuel tank 21 supplies liquefied gas fuel to the engine 16.

Next, with reference to FIG. 2, a fresh water generation system 100 according to an embodiment of the present invention will be described. FIG. 2 is a schematic configuration diagram showing the system configuration of the fresh water generation system 100 according to the present embodiment. The water production system 100 is a system for producing distilled water from seawater in the ship 1. In the ship 1, liquefied gas fuel is heated with a heat medium and used in the engine 16. Since the liquefied gas fuel is a low-temperature substance, the heat carrier becomes low temperature by heating the liquefied gas fuel. The fresh water generation system 100 is a system that improves the production efficiency in the fresh water generation apparatus 40 by using the heat medium that has become low temperature in this way.

As shown in FIG. 2, the fresh water generation system 100 includes a fresh water generation device 40, a liquefied gas fuel system 50, a heat exchange section 60 (cooling section), and a heat exchange section 70 (heating section). Moreover, the fresh water production system 100 includes a seawater line L1 (flow path), a seawater discharge line L2, a distilled water supply line L3, a diesel engine cooling water line L4, and a heat medium line L5.

The water production device 40 is a device that produces distilled water using seawater. Although the arrangement of the freshwater generator 40 is not particularly limited, it may be arranged, for example, in the engine room 4 (see FIG. 1). The fresh water generating device 40 includes an evaporation section 41 and a condensation section 42. The evaporator 41 evaporates the seawater SW by heating it under vacuum. The steam SM generated in the evaporation section 41 rises within the fresh water generator 40 and heads toward the condensation section 42 . The storage section 43 is connected to a seawater discharge line L2. The seawater discharge line L2 is a line that stores concentrated seawater CSW, which has a high concentration of salt as a result of evaporation of a portion of water as steam SM, in the storage section 43 and discharges it to the outside of the ship.

The condensing section 42 is a section that condenses the steam SM generated in the evaporating section 41 to generate distilled water PW. The condensing section 42 is provided above the evaporating section 41. The condensing section 42 has a space for receiving the steam SM rising from the evaporating section 41. The steam SM in the space is cooled and condensed to become distilled water PW. The condensing section 42 has a storage section 44 that stores the generated distilled water PW. A distilled water supply line L3 is connected to the storage section 44. The distilled water supply line L3 is a line that is extended to various locations inside the ship outside the water generator 40, and supplies distilled water to various locations by being pumped by the pump 48. The distilled water supplied from the distilled water supply line L3 is used for drinking water, domestic water, boiler supply water, miscellaneous water, and other purposes. Note that when distilled water is used as drinking water, it is sterilized by adding minerals or the like.

The seawater line L1 is a line that supplies the seawater SW to the evaporation section 41 after passing the seawater SW through the condensation section 42 . The seawater line L1 circulates seawater assembled by a pump 46 from the sea. The seawater line L1 is inserted from the outside into the condensate section 42 in the fresh water generator 40. After the seawater line L1 crawls around in the space of the condensing part 42, it is drawn out to the outside of the fresh water generator 40. Further, the seawater line L1 passes through the outside of the fresh water generator 40 and is inserted into the evaporator 41. The seawater line L1 extends above the storage section 43.

In addition, the part of the seawater line L1 upstream of the condensing part 42 of the fresh water generator 40, that is, the part at the stage before being inserted into the fresh water generator 40, is referred to as a first part L1a. Further, the portion of the seawater line L1 that is crawled into the condensing portion 42 is referred to as a second portion L1b. In addition, the seawater line L1 is drawn out from the part between the condensing part 42 and the evaporating part 41, that is, the condensing part 42 of the fresh water generating apparatus 40, and is reinserted into the evaporating part 41 of the fresh water generating apparatus 40. The pre-stage portion to be processed is referred to as the third portion L1c. Furthermore, the portion of the seawater line L1 that is crawled into the evaporator 41 is referred to as a fourth portion L1d.

High temperature steam SM exists around the second portion L1b of the seawater line L1. On the other hand, seawater flows in the second portion L1b. The steam SM is thus cooled by the second portion L1b.

Note that a heat exchange section 47 that performs heat exchange between the seawater SW and the diesel engine cooling water CW of the diesel engine cooling water line L4 is provided in the fourth portion of the seawater line L1. The diesel engine cooling water line L4 is water used to cool the diesel engine 80 (see FIG. 1) that constitutes the generator. After cooling the diesel engine 80, the heat exchanger 47 is supplied with high-temperature diesel engine cooling water CW. Therefore, the seawater SW flowing through the fourth portion L1d is heated in the heat exchange section 47 by the heat of the diesel engine cooling water CW. Therefore, the seawater line L1 can supply the seawater SW heated in the heat exchange section 47 to a high temperature to the storage section 43 of the evaporation section 41. Note that the storage section 43 may be provided with a heater such as a heater.

The heat exchange section 60 is a section that performs heat exchange between the seawater flowing through the first portion L1a of the seawater line L1 and the heat medium HM flowing through the heat medium line L5 extending from the liquefied gas fuel system 50. The heat medium line L5 is a line through which the heat medium HM whose temperature has been lowered by heating the ultra-low temperature liquefied gas fuel flows. Therefore, the heat exchange section 60 cools the steam SM in the condensing section 42 by cooling the seawater SW in the seawater line L1 on the upstream side of the condensing section 42. Thereby, the heat exchange section 60 functions as a cooling section that cools the steam SM in the condensing section 42 using the heat medium HM whose temperature has been lowered by heating the liquefied gas fuel. Note that the configuration of the liquefied gas fuel system 50 will be described later.

The heat exchange part 70 is a part of the seawater line L1 that performs heat exchange between the seawater SW flowing through the first portion L1a and the seawater flowing through the third portion L1c. The heat exchange section 70 is provided upstream of the heat exchange section 60 in the first portion L1a. That is, in the heat exchange section 70, seawater SW before being cooled in the heat exchange section 60 flows through the first section L1a, and seawater SW after being cooled in the heat exchange section 60 flows through the third section L1c. do. Therefore, the heat exchange section 70 functions as a heating section that heats the seawater SW flowing between the condensing section 42 and the evaporating section 41 using the seawater SW upstream of the condensing section 42 in the seawater line L1. do.

Here, if the temperature of the seawater SW is low, such as in a cold region, the temperature of the seawater SW flowing through the first portion L1a may be lower than the temperature of the seawater SW in the third portion L1c. . In such a case, since the heat exchange section 70 no longer functions as a heating section, a mechanism may be provided that allows the seawater SW to bypass the heat exchange section 70. For example, as shown in FIG. 2, a bypass line BL that bypasses the heat exchange section 70 may be provided to the first portion L1a. Further, a switching valve 90 for switching the flow of seawater SW may be provided at the branching point between the bypass line BL and the first portion L1a. For example, when the heat exchange section 70 can function as a heating section, the switching valve 90 causes seawater SW to flow toward the heat exchange section 70 (flow F1). On the other hand, when the heat exchange section 70 cannot function as a heating section, the switching valve 90 causes seawater SW to flow through the bypass line BL. In the example shown in FIG. 2, the bypass line BL is provided in the first portion L1a, but the bypass line BL may be provided in the third portion L1c.

Next, with reference to FIG. 3, the liquefied gas fuel system 50 will be described. FIG. 3 is a schematic configuration diagram showing in detail the relationship between the liquefied gas fuel system 50 and the fresh water generator 40. As shown in FIG. 3, the liquefied gas fuel system 50 includes a liquefied gas fuel tank 21 and a liquefied gas fuel heater 24. Moreover, the liquefied gas fuel system 50 includes the aforementioned heat medium line L5 and the liquefied gas fuel line L6.

Liquefied gas fuel tank 21 is connected to engine 16 via liquefied gas fuel line L6. Further, a liquefied gas fuel heater 24 is provided in the liquefied gas fuel line L6 between the liquefied gas fuel tank 21 and the engine 16. A pump 31 is provided in the liquefied gas fuel tank 21 . The pump 31 supplies the liquefied gas fuel LG to the liquefied gas fuel heater 24 by force-feeding the liquefied gas fuel LG in the liquefied gas fuel tank 21 to the liquefied gas fuel line L6. The heated fuel is supplied to the engine 16 via the liquefied gas fuel line L6.

The liquefied gas fuel heater 24 is a device that heats the liquefied gas fuel LG using the heat medium HM. The heat medium HM is preferably one that does not freeze even if it exchanges heat with a low-temperature liquefied gas fuel tank, and for example, glycol can be used. The liquefied gas fuel heater 24 is provided in the heat medium line L5 on the near side of the heat exchange section 60 with respect to the flow of the heat medium HM pumped by the pump 32 from a heat medium tank (not shown). The liquefied gas fuel heater 24 allows the heating medium HM to pass through the heating medium line L5, and the liquefied gas fuel LG to pass through the liquefied gas fuel line L6, so that the heating medium HM and the liquefied gas fuel LG are heated. heat exchange between the Thereby, the liquefied gas fuel LG is heated by the heat from the heat medium HM. On the other hand, the heat medium HM is cooled by removing heat from the liquefied gas fuel LG. Thereby, the heat medium line L5 can flow the heat medium HM cooled by the liquefied gas fuel heater 24 to the heat exchange section 60. Thereby, the heat exchange section 60 can cool the seawater SW on the upstream side of the condensing section 42 of the fresh water generator 40. Although the arrangement of the liquefied gas fuel heater 24 is not particularly limited, it is arranged, for example, in the engine room 4 (see FIG. 1).

Next, with reference to FIG. 1, the state of temperature change of each fluid will be explained. However, the following temperatures are only examples and are not limited to these temperatures. First, the seawater SW pumped by the pump 46 varies depending on the sea area and season. Note that the switching valve 90 is switched depending on the temperature of the seawater SW being pumped up. The seawater SW flowing through the first portion L1a of the seawater line L1 is cooled by the heat medium HM in the heat exchange section 60. In the second portion L1b of the seawater line L1, the temperature of the seawater SW increases by receiving heat from the steam SM. Under conditions in which the temperature of the seawater SW flowing through the third portion L1c of the seawater line L1 is lower than the temperature of the seawater SW being pumped up, the switching valve 90 causes the seawater SW to flow toward the heat exchange section 70 (flow F1). Thereby, the seawater SW flowing through the third portion L1c is heated by the seawater SW flowing through the first portion L1a in the heat exchange section 70. On the other hand, under conditions where the temperature of the seawater SW flowing through the third portion L1c of the seawater line L1 is higher than the temperature of the seawater SW being pumped up, the switching valve 90 causes the seawater SW to flow toward the bypass line BL side (flow F2 ). Seawater SW flows from the third portion L1c to the fourth portion L1d. The seawater SW flowing through the fourth portion L1d is heated by the diesel engine cooling water CW in the heat exchange section 47 and then supplied to the storage section 43.

Next, the functions and effects of the fresh water production system 100 according to this embodiment will be explained.

The fresh water generation system 100 according to the present embodiment includes an evaporation section 41 that evaporates seawater SW, a condensation section 42 that condenses steam SM generated in the evaporation section 41 to generate distilled water PW, and a system that circulates seawater SW. and a seawater line L1 that supplies seawater SW to the evaporation section 41 after passing through the condensation section 42. With such a configuration, the seawater SW cools the steam SM generated in the evaporation section 41 by passing through the condensation section 42 via the seawater line L1 before being supplied to the evaporation section 41. Thereby, the steam SM cooled in the condensing section 42 is condensed and recovered as distilled water PW. Here, from the viewpoint of environmental protection, liquefied gas fuel LG may be used as the fuel for the ship 1 in order to reduce SOx _, NOx _{, and CO2} emissions. When using the liquefied gas fuel LG, it is necessary to heat the liquefied gas fuel LG using the heat medium HM. After heating the liquefied gas fuel LG, the temperature of the heat medium HM decreases to a low temperature. Therefore, in order to effectively utilize the cooling power of the heat medium HM whose temperature has been lowered by heating the liquefied gas fuel LG, the fresh water production system 100 uses the heat medium HM to generate steam SM in the condensing section 42. A heat exchange section 60 for cooling is provided. This makes it easier for the heat exchange section 60 to condense the steam SM in the condensing section 42 . Furthermore, the above-mentioned effects can be achieved by providing the heat exchange section 60 in a conventional water production system (a system in which the heat exchange sections 60 and 70 are omitted from the fresh water production system 100), This can be obtained by simply making a change to the extent that the medium HM is drawn in. As described above, the fresh water generation system 100 can improve the efficiency of producing distilled water without significantly changing the mechanism of the conventional fresh water generation system.

The heat exchange section 60 cools the steam SM in the condensing section 42 by cooling the seawater SW in the seawater line L1 on the upstream side of the condensing section 42 . For example, as shown in FIG. 4, when the cooling medium CM cooled by the heat exchange section 60 is supplied to the condensing section 42, it is necessary to separately provide a new cooling medium line L7 in addition to the seawater line L1. In contrast, in this embodiment, since it is only necessary to add the heat exchange section 60 to the seawater line L1 upstream of the condensate section 42, the cooling medium line is directly connected to the condensate section 42. Compared to the case where a cooling section like L7 is provided, the structure for cooling can be simplified.

The fresh water generation system 100 further includes a heat exchanger 70 that heats the seawater SW flowing between the condensing part 42 and the evaporating part 41 using the seawater SW upstream of the condensing part 42 in the seawater line L1. Be prepared. In this case, the heat exchange section 70 can heat the seawater SW after passing through the condensation section 42 before being supplied to the evaporation section 41 . Thereby, the evaporation efficiency in the evaporator 41 can be improved.

The invention is not limited to the embodiments described above.

For example, as a fresh water generation system according to a modification, a structure may be adopted in which the cooling medium CM cooled by the heat exchange section 60 is supplied to the condensing section 42, as shown in FIG. 4. In this case, apart from the seawater line L1, a coolant line L7 is provided to the condensate section 42 of the fresh water generator 40. The coolant line L7 passes through the heat exchange section 60 and is also crawled into the space inside the condensing section 42. Thereby, the cooling medium CM cooled by the heat medium HM cools the steam SM in the space of the condensing part 42 together with the seawater SW of the seawater line L1. In this case, in addition to the heat exchange section 60, the cooling medium line L7 is also a cooling section that cools the steam SM in the condensing section 42 using the heat medium HM whose temperature has been lowered by heating the liquefied gas fuel LG. functions as

For example, water may be employed as the above-mentioned cooling medium CM. However, the cooling medium CM is not particularly limited, and any medium may be used. Note that when a medium other than water is used as the cooling medium CM, it is preferable to provide a protection mechanism that prevents the cooling medium CM from mixing with seawater or distilled water PW even if the cooling medium line L7 is damaged.

Alternatively, the heat medium line L5 may be directly inserted into the condensing part 42 and routed without using the heat exchange part 60. In this case, the heat medium line L5 functions as a cooling section that cools the steam SM in the condensing section 42 using the heat medium HM whose temperature has decreased by heating the liquefied gas fuel LG. Note that it is preferable to provide a protection mechanism that prevents the heat medium HM from mixing with seawater or distilled water PW even if the heat medium line L5 is damaged.

The arrangement of each component of the fresh water production system 100 in the ship 1 is not limited to the arrangement shown in FIG. 1 . For example, the position of the liquefied gas fuel tank 21 on the deck 19 may be changed or it may be placed within the hull 11. Additionally, the liquefied gas fuel heater 24 may be provided on the deck 19.

DESCRIPTION OF SYMBOLS 1...Ship, 41...Evaporation part, 42...Condensing part, 60...Heat exchange part (cooling part), 70...Heat exchange part (heating part), 100...Water production system, L1...Seawater line (flow path, cooling ), L7...Cooling medium line (cooling part).

Claims (1)

A water production system that produces distilled water from seawater on a ship,
an evaporation section that evaporates the seawater;
a condensing section that condenses the steam generated in the evaporating section to produce distilled water;
a channel for supplying the seawater to the evaporation section after passing the seawater through the condensation section;
a cooling section that cools the steam in the condensing section using a heat medium whose temperature has been lowered by heating the liquefied gas fuel,
The water production system further includes a heating section that heats the seawater flowing between the condensing section and the evaporation section using the seawater upstream of the condensing section in the flow path.

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