Water production system

Abstract

To provide a water production system that can effectively use waste heat from scavenging air cooling water for desalination of seawater in a water production device.SOLUTION: A water production system 100 comprises: a multiple-effect water production device 1 equipped with a plurality of heaters 2, 2' and a steam condenser 3, wherein the steam generated in a preceding heater 2 is supplied as a heating fluid from the heater 2 to a subsequent heater 2', and the steam condenser 3 condenses steam generated in a final stage heater 3'; a scavenging air cooling water supply line L2 for supplying scavenging air cooling water, which is used to cool scavenging air supplied to a diesel engine 10, to a scavenging air cooler 14; and a first heating fluid supply line L4 that is connected to the scavenging air cooling water supply line L2 to supply at least a part of the scavenging air cooling water used to cool the scavenging air in the scavenging air cooler 14 to the heater 2' in the final stage of the multiple-effect water production device 1 as a heating fluid.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a freshwater production system for desalination of seawater, and more particularly to a freshwater production system that utilizes waste heat from an internal combustion engine such as a diesel engine that is the main engine of a ship. [Background technology]

[0002] In ships, it has been conventional to produce fresh water from seawater by utilizing waste heat from an internal combustion engine such as a diesel engine mounted on the ship. For example, in Patent Document 1, scavenging air cooling water whose temperature has been increased by being used to cool scavenging air supplied to the diesel engine is supplied to a fresh water generator, and the waste heat of the scavenging air cooling water is used as a heat source for evaporating seawater in the fresh water generator. In the fresh water generator, seawater is heated and evaporated in a heater by heat exchange with the scavenging air cooling water, and then the steam generated by evaporation is cooled and condensed in a condenser to desalinate the seawater. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4409546 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the temperature of the scavenging air cooling water used to cool the scavenging air is approximately 60°C when the scavenging air cooling water is fresh water, whereas it is approximately 45°C to 50°C when the scavenging air cooling water is seawater, which is lower than the temperature of fresh water. In freshwater generators, seawater is evaporated under reduced pressure. The evaporation temperature of seawater in single-effect freshwater generators, or the evaporation temperature of seawater in the first effect of multiple-effect freshwater generators, is generally approximately 55°C to 60°C. Therefore, if the waste heat of the scavenging air cooling water (approximately 45°C to 60°C) is used as the main heat source for evaporating seawater in a single-effect freshwater generator or the first effect of a multiple-effect freshwater generator, the amount of heat required to produce a sufficient amount of steam is insufficient, resulting in a decrease in the amount of freshwater produced. This can result in problems such as a decrease in the freshwater production performance of the freshwater generator or an increase in the size of the freshwater generator, due to the need to secure a large heat transfer area for heat exchange between the seawater and the scavenging air cooling water in order to obtain a sufficient amount of freshwater. As such, it is not practical to use the waste heat of the scavenging air cooling water as the main heat source for evaporating seawater in a single-effect freshwater generator or the first effect of a multiple-effect freshwater generator.

[0005] The present invention has been made with a view to solving the above-mentioned problems, and an object of the present invention is to provide a fresh water production system in which waste heat from scavenging air cooling water can be effectively utilized for desalination of seawater in a multiple-effect fresh water production system. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention is directed to a fresh water production system as described in item 1 below.

[0007] Item 1. A water production system for desalination of seawater on a ship, a multiple-effect freshwater production system including a plurality of heaters that heat seawater with a heating fluid to generate steam, and a condenser that cools and condenses the steam, wherein the steam generated by the heaters in the preceding stages is supplied as a heating fluid from the heaters in the succeeding stages to the heaters in the succeeding stages, and the condenser condenses the steam generated by the heaters in the final stage; a scavenging air cooling water supply line for supplying the scavenging air cooler with scavenging air cooling water for cooling the scavenging air supplied to the marine internal combustion engine; a first heating fluid supply line connected to the scavenging air cooling water supply line, for supplying at least a portion of the scavenging air cooling water used to cool the scavenging air in the scavenging air cooler to the last-stage heater as a heating fluid; A water production system comprising:

[0008] Furthermore, the fresh water production system of the present invention encompasses the fresh water production system described in the following item 2 as a preferred embodiment of the fresh water production system described in the above item 1.

[0009] Item 2. The water production system according to Item 1, wherein the scavenging air cooling water is fresh water.

[0010] Furthermore, the fresh water production system of the present invention encompasses the fresh water production system described in the following item 3 as a preferred embodiment of the fresh water production system described in item 1 or 2 above.

[0011] Item 3. The fresh water production system according to Item 1 or 2, wherein the heater at the most upstream stage of the fresh water production system is configured so that jacket cooling water used to cool the internal combustion engine is supplied as a heating fluid.

[0012] Furthermore, the fresh water production system of the present invention encompasses the fresh water production system described in the following item 4 as a preferred embodiment of the fresh water production system described in the above item 3.

[0013] Item 4. The fresh water production system according to Item 3, further comprising a sub-heating fluid supply line connected to the heating fluid supply line and for supplying a portion of the scavenging air cooling water flowing through the heating fluid supply line to the heater at the most upstream stage of the fresh water production system as a heating fluid. [Effects of the Invention]

[0014] According to the fresh water production system of the present invention, the waste heat of the scavenging air cooling water can be effectively utilized for desalination of seawater in the multiple-effect fresh water production system, thereby improving the fresh water production performance of the multiple-effect fresh water production system. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic configuration diagram of a fresh water production system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a schematic configuration diagram of a fresh water production system according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention relates to a freshwater production system that utilizes waste heat from an internal combustion engine, which is a main engine for generating propulsion power in a ship, to desalinate seawater in the freshwater production system, thereby improving the performance of the freshwater production system. The internal combustion engine is, for example, a diesel engine.

[0017] 1 is a schematic diagram of a fresh water production system 100 according to one embodiment of the present invention. The fresh water production system 100 includes at least a multiple-effect fresh water production system 1 (hereinafter referred to as "multiple-effect fresh water production system 1"), a scavenging air cooling water supply line L2 for supplying scavenging air cooling water for cooling scavenging air supplied to a diesel engine 10 serving as an internal combustion engine for a marine vessel to a scavenging air cooler 14, and a heating fluid supply line L4 for supplying at least a portion of the scavenging air cooling water used to cool the scavenging air in the scavenging air cooler 14 to a heater 2' in the final stage of the multiple-effect fresh water production system 1 as a heating fluid.

[0018] The diesel engine 10 is an internal combustion engine that uses at least one of fuel oil and fuel gas as a main fuel and burns the main fuel together with scavenging air.

[0019] The jacket cooling water supply line L1 is a pipe through which jacket cooling water flows in order to supply cooling water for cooling the diesel engine 10 (referred to as "jacket cooling water" in this disclosure) to the diesel engine 10. The jacket cooling water circulates through the jacket cooling water supply line L1 by driving a pump 15.

[0020] The flow rate of the jacket cooling water supplied to the diesel engine 10 is adjusted by a flow rate adjustment valve 16. The flow rate adjustment valve 16 may be equipped with a flow meter. A cooler 17 is connected to the jacket cooling water supply line L1. The cooler 17 cools the jacket cooling water whose temperature has increased after being used to cool the diesel engine 10. The cooler 17 is, for example, a heat exchanger, and is supplied with cooling fluid from a central cooler. In the cooler 17, the jacket cooling water is cooled by heat exchange with the cooling fluid.

[0021] A heating fluid supply line L3 (hereinafter referred to as the "third heating fluid supply line L3") is connected to the jacket cooling water supply line L1 using, for example, a pipe joint. The third heating fluid supply line L3 is a pipe through which jacket cooling water flows in order to supply a portion of the jacket cooling water, which has become hot as a result of cooling the diesel engine 10, to the heater 2 at the earliest stage of the multiple-effect fresh water producer 1. A portion of the jacket cooling water, which has become hot as a result of cooling the diesel engine 10, is used as a heating fluid for heating seawater, which serves as raw water, in the heater 2 at the earliest stage of the multiple-effect fresh water producer 1. A portion of the jacket cooling water is diverted from the jacket cooling water supply line L1 to the third heating fluid supply line L3, passes through the heater 2 at the earliest stage of the multiple-effect fresh water producer 1, and then returns to the jacket cooling water supply line L1.

[0022] A temperature sensor 18 is connected to the third heating fluid supply line L3. The temperature sensor 18 measures the temperature of the jacket cooling water that is diverted from the jacket cooling water supply line L1 to the third heating fluid supply line L3 and supplied to the heater 2 at the frontmost stage of the multiple-effect freshwater production system 1. A conventionally known temperature sensor can be used as the temperature sensor 18.

[0023] The flow rate of the jacket cooling water supplied to the heater 2 at the earliest stage of the multiple-effect fresh water generator 1 through the third heating fluid supply line L3 is adjusted by a flow control valve 19. The flow rate of the jacket cooling water supplied to the heater 2 at the earliest stage of the multiple-effect fresh water generator 1 through the third heating fluid supply line L3 is adjusted based on the temperature of the jacket cooling water detected by a temperature sensor 18. The flow control valve 19 may be equipped with a flow meter.

[0024] The turbocharger 11 supplies scavenging air to the diesel engine 10. The turbocharger 11 includes a turbine 12 driven by exhaust gas emitted when the diesel engine 10 combusts main fuel, and a compressor 13 that compresses outside air using the rotational power of the turbine 12. The turbocharger 11 supplies the compressed outside air to the diesel engine 10 as scavenging air.

[0025] The scavenging air cooler 14 cools the scavenging air supplied from the turbocharger 11 to the diesel engine 10. Since the scavenging air is adiabatically compressed and has a high temperature, it is cooled in the scavenging air cooler 14 before being supplied to the diesel engine 10 for purposes such as increasing the air density (weight per unit volume). The scavenging air cooler 14 is, for example, a heat exchanger.

[0026] The scavenging air cooling water supply line L2 is a pipe through which scavenging air cooling water flows in order to supply cooling water for cooling scavenging air (referred to as "scavenging air cooling water" in this disclosure). The scavenging air cooling water circulates through the scavenging air cooling water supply line L2 by driving a pump 20. Fresh water or seawater is used as the scavenging air cooling water.

[0027] The flow rate of the scavenging air cooling water supplied to the scavenging air cooler 14 is adjusted by a flow rate control valve 21. The flow rate control valve 21 may be provided with a flow meter. A cooler 22 is connected to the scavenging air cooling water supply line L2. The cooler 22 cools the scavenging air cooling water whose temperature has increased after being used to cool the scavenging air in the scavenging air cooler 14. The cooler 22 is, for example, a heat exchanger, and is supplied with a cooling fluid from a central cooler. In the cooler 22, the scavenging air cooling water is cooled by heat exchange with the cooling fluid.

[0028] A heating fluid supply line L4 (hereinafter referred to as "first heating fluid supply line L4") is connected to the scavenging air cooling water supply line L2 using, for example, a pipe joint or the like. The first heating fluid supply line L4 is a pipe through which scavenging air cooling water flows in order to supply at least a part of the scavenging air cooling water used for cooling the scavenging air to the heater 2' at the final stage of the multiple-effect fresh water generator 1. A part of the scavenging air cooling water, the temperature of which has increased as the scavenging air is cooled in the scavenging air cooler 14, is used as a heating fluid for heating seawater to generate steam in the heater 2' at the final stage of the multiple-effect fresh water generator 1. A part of the scavenging air cooling water is diverted from the scavenging air cooling water supply line L2 to the first heating fluid supply line L4, passes through the heater 2' at the final stage of the multiple-effect fresh water generator 1, and then returns to the scavenging air cooling water supply line L2.

[0029] A temperature sensor 23 is connected to the first heating fluid supply line L4. The temperature sensor 23 measures the temperature of the scavenging air cooling water that is diverted from the scavenging air cooling water supply line L2 to the first heating fluid supply line L4 and supplied to the heater 2' at the final stage of the multiple-effect fresh water production system 1. A conventionally known temperature sensor can be used as the temperature sensor 23.

[0030] The flow rate of the scavenging air cooling water supplied to the heater 2' at the final stage of the multiple-effect fresh water generator 1 through the first heating fluid supply line L4 is adjusted by a flow control valve 24. The flow rate of the scavenging air cooling water supplied to the heater 2' at the final stage of the multiple-effect fresh water generator 1 through the first heating fluid supply line L4 is adjusted based on the temperature of the scavenging air cooling water detected by a temperature sensor 23. The flow control valve 24 may be provided with a flow meter.

[0031] The multiple-effect freshwater generator 1 includes a plurality of heaters 2, 2' that heat seawater, which serves as raw water, to generate steam, and a condenser 3 that cools and condenses the steam. In this embodiment, the multiple-effect freshwater generator 1 is a double-effect type having two heaters 2, 2', but may include three or more heaters. The multiple-effect freshwater generator 1 includes a plurality of heaters 2, 2' arranged in series. The interior of the multiple-effect freshwater generator 1 is maintained under reduced pressure or in a vacuum state by a pressure reducing means such as a water ejector. Seawater is supplied as raw water to the multiple heaters 2, 2', and a heating fluid is supplied to heat the seawater to generate steam. In the multiple-effect freshwater generator 1, for example, jacket cooling water used to cool a diesel engine 10 is supplied as a heating fluid to the heater 2 in the frontmost stage. Then, in the heater 2 in the most front stage, seawater is heated and evaporated, followed by gas-liquid separation, and the steam after gas-liquid separation is supplied to the heater 2 in the next rear stage as a heating fluid, and in the heater 2 in the next rear stage, seawater is heated and evaporated, followed by gas-liquid separation. This process is repeated up to the heater 2' in the last stage. In this way, the multiple-effect fresh water production system 1 supplies steam generated in the heater in the front stage to the heater in the next rear stage as a heating fluid, thereby evaporating seawater in each heater 2, 2' to generate steam. The steam generated in the heater 2' in the last stage is then condensed in the condenser 3 to produce fresh water.

[0032] The multiple-effect freshwater generator 1 is not particularly limited as long as it desalinates seawater. The multiple-effect freshwater generator 1 can be a multi-pipe freshwater generator (for example, JP 2022-51869 A, JP 2019-195750 A, JP 2016-205242 A, etc.), but may also be a plate-type or other type freshwater generator.

[0033] In the multiple-effect freshwater production system 1, the heaters 2, 2′ heat seawater to generate steam. The heaters 2, 2′ are not particularly limited, but may include, for example, a tubular heat exchanger. Seawater is supplied to the heaters 2, 2′ as raw water. In this embodiment, seawater is supplied to the heater 2 in the most upstream stage via a raw water supply line L5, and seawater separated from steam in the heater 2 in the most downstream stage is supplied to the heater 2′ in the most downstream stage. A heating fluid for evaporating seawater is also supplied to the heaters 2, 2′. In this embodiment, jacket cooling water used to cool the diesel engine 10 is supplied as the heating fluid to the heater 2 in the most upstream stage via a third heating fluid supply line L3, and steam generated in the heater 2 in the most upstream stage is supplied as the heating fluid to the heater 2′ in the most downstream stage. In the heaters 2, 2′, the seawater supplied as raw water is heated by heat exchange with the heating fluid, and after its temperature rises, it is evaporated. The steam generated by evaporation of seawater in the final stage heater 2 ′ is supplied to the condenser 3 .

[0034] In the multiple-effect freshwater generator 1, the condenser 3 cools and condenses the steam generated in the heater 2' in the final stage. The condenser 3 is not particularly limited, but may include, for example, a tubular heat exchanger. Seawater pumped from the sea and brought into the ship is supplied to the condenser 3 via a steam cooling water supply line L6 as steam cooling water for condensing the steam. When the steam cooling water is supplied to the condenser 3, the steam is cooled by heat exchange with the steam cooling water in the condenser 3, and condenses after its temperature has dropped. The fresh water produced by condensing the steam is discharged outside the multiple-effect freshwater generator 1 and supplied to a water storage tank via a fresh water supply line L7.

[0035] At least a portion of the steam cooling water, the temperature of which has increased as the steam is cooled in the condenser 3, is supplied to the heaters 2, 2' of the multiple-effect fresh water production system 1 via the raw water supply line L5 and is used as raw water for producing fresh water in the heaters 2, 2', with the remainder being discharged outside the system, such as outside the ship. The raw water supply line L5 is a pipe through which the steam cooling water flows in order to supply at least a portion of the steam cooling water used to cool the steam to the heaters 2, 2' of the multiple-effect fresh water production system 1.

[0036] Next, a seawater desalination method in the freshwater production system 100 of this embodiment will be described. Seawater is supplied as raw water from a raw water supply line L5 to the heater 2 at the most upstream stage of the multiple-effect freshwater production system 1, and jacket cooling water used to cool the diesel engine 10 is supplied as a heating fluid from a third heating fluid supply line L3.

[0037] The temperature of the jacket cooling water after cooling the diesel engine 10 is high, at approximately 80°C to 90°C. On the other hand, the evaporation temperature of seawater in the heater 2 at the most upstream stage of the multiple-effect freshwater generator 1 under reduced pressure is generally approximately 55°C to 60°C. Therefore, in the multiple-effect freshwater generator 1 under reduced pressure, the seawater can be effectively evaporated to generate steam by heating it with the jacket cooling water. Therefore, the jacket cooling water can be fully utilized as the main heat source for evaporating seawater in the heater 2 at the most upstream stage of the multiple-effect freshwater generator 1.

[0038] Steam generated in the heater 2 in the most upstream stage of the multiple-effect freshwater production system 1 is supplied as a heating fluid to the heater 2' in the next downstream stage (the last stage in this embodiment). In the multiple-effect freshwater production system 1, the evaporation temperature of seawater decreases as the heater is positioned further downstream, and the evaporation temperature of seawater in heaters from the second stage onwards is generally about 50°C or lower. In contrast, the temperature of steam generated in the heater 2 in the most upstream stage is about 60°C, so the second stage heater can generate steam by heating seawater with the steam generated in the heater in the previous stage. Similarly, in heaters from the third stage onwards, seawater can be heated with the steam generated in the heater in the previous stage to evaporate and generate steam.

[0039] The last-stage heater 2' is supplied as a heating fluid from the first heating fluid supply line L4 with not only the steam generated in the previous heater but also the scavenging air cooling water used to cool the scavenging air in the scavenging air cooler 14. The scavenging air cooling water after cooling the scavenging air is generally at about 60°C in the case of fresh water, and generally at about 45°C to 50°C in the case of seawater. Since the last-stage heater 2' is supplied with the high-temperature scavenging air cooling water as a heating fluid in addition to the steam generated in the previous heater, it can effectively evaporate seawater, and as a result, a sufficient amount of fresh water can be obtained in the condenser 3.

[0040] In order to efficiently evaporate seawater in the final stage heater 2', it is preferable that the scavenging air cooling water be fresh water with a higher temperature.

[0041] Seawater is supplied to the condenser 3 as steam cooling water from the steam cooling water supply line L6, and fresh water is produced by cooling and condensing the steam generated in the final-stage heater 2' with the steam cooling water. Furthermore, the steam used to heat seawater as a heating fluid in each heater is condensed into fresh water through heat exchange with the seawater, which is recovered together with the fresh water produced in the condenser 3 and discharged outside the device via the fresh water supply line L7.

[0042] In the fresh water production system 100 of the above-described embodiment, at least a part of the scavenging air cooling water used to cool the scavenging air supplied to the diesel engine 10 is supplied to the heater 2' in the final stage of the multiple-effect fresh water production system 1, and this scavenging air cooling water, together with steam generated in the heater 2 in the preceding stage, is used as a heating fluid for heating and evaporating seawater in the heater 2'. As a result, the heater 2' in the final stage of the multiple-effect fresh water production system 1 can efficiently heat seawater to generate steam, and fresh water can be effectively produced in the condenser 3. Therefore, according to the fresh water production system 100 of the embodiment, the waste heat of the scavenging air cooling water can be effectively used to improve the fresh water production performance of the multiple-effect fresh water production system 1.

[0043] Furthermore, in the freshwater production system 100 of the above-described embodiment, at least a portion of the jacket cooling water, which has become hot as a result of cooling the diesel engine 10, is supplied to the heater 2 in the earliest stage of the multiple-effect freshwater production system 1, and is used as a heating fluid for heating and evaporating seawater in the heater 2. As a result, the heater 2 in the earliest stage of the multiple-effect freshwater production system 1 can efficiently heat seawater to generate steam, and a large amount of freshwater can be recovered by condensing the steam in the heater 2' in the latest stage. Therefore, according to the freshwater production system 100 of the embodiment, the waste heat of the jacket cooling water can also be effectively used to improve the freshwater production performance of the multiple-effect freshwater production system 1.

[0044] While one embodiment of the fresh water production system of the present invention has been described above, the embodiment shown in Fig. 1 above is merely an example and is not limiting. Therefore, the fresh water production system of the present invention is not limited to the embodiment shown in Fig. 1 above, and various modifications are possible without departing from the spirit of the present invention.

[0045] <Variation 1> In another embodiment, as shown in FIG. 2, the scavenging air cooling water used in the scavenging air cooler 14 to cool the scavenging air to be supplied to the diesel engine may be supplied as a heating fluid not only to the heater 2′ in the last stage of the multiple-effect fresh water production system 1 but also to the heater 2 in the first stage.

[0046] In the embodiment shown in FIG. 2 , a heating fluid supply line L8 (hereinafter referred to as a "second heating fluid supply line L8") is connected to the first heating fluid supply line L4 using, for example, a pipe joint or the like. The second heating fluid supply line L8 is a pipe through which scavenging air cooling water flows in order to supply at least a portion of the scavenging air cooling water used to cool the scavenging air to the heater 2 at the earliest stage of the multiple-effect fresh water generator 1. A portion of the scavenging air cooling water, the temperature of which has increased as the scavenging air is cooled in the scavenging air cooler 14, is used as a heating fluid for heating seawater to generate steam in the heater 2 at the earliest stage of the multiple-effect fresh water generator 1. A portion of the scavenging air cooling water is diverted from the scavenging air cooling water supply line L2 through the first heating fluid supply line L4 to the second heating fluid supply line L8, passes through the heater 2 at the earliest stage of the multiple-effect fresh water generator 1, and returns to the scavenging air cooling water supply line L2 through the first heating fluid supply line L4.

[0047] The flow rate of the scavenging air cooling water supplied to the heater 2 at the earliest stage of the multiple-effect fresh water generator 1 through the second heating fluid supply line L8 is adjusted by a flow control valve 25. The flow rate of the scavenging air cooling water supplied to the heater 2 at the earliest stage of the multiple-effect fresh water generator 1 through the second heating fluid supply line L8 is adjusted based on the temperature of the scavenging air cooling water detected by a temperature sensor 25. The flow control valve 25 may be provided with a flow meter.

[0048] 2, the scavenging air cooling water used to cool the scavenging air supplied to the diesel engine in the scavenging air cooler 14 is supplied as a heating fluid to the heater 2 at the frontmost stage of the multiple-effect fresh water production system 1, together with the jacket cooling water used to cool the diesel engine 10. As a result, even if the temperature or flow rate of the jacket cooling water supplied as the heating fluid decreases, the scavenging air cooling water can be used as the heating fluid to appropriately adjust the temperature and flow rate of the heating fluid supplied to the heater 2 at the frontmost stage of the multiple-effect fresh water production system 1. Therefore, a sufficient amount of heat can be secured to generate a sufficient amount of steam in the heater 2 at the frontmost stage of the multiple-effect fresh water production system 1.

[0049] <Variation 2> 1 and 2, the multiple-effect freshwater production system 1 may include a preheater equipped with, for example, a tubular heat exchanger. Specifically, part of the steam cooling water used for condensing steam in the condenser 3 of the multiple-effect freshwater production system 1 may be supplied to the preheater to preheat seawater by heat exchange with the steam, and part of the preheated steam cooling water may be supplied as raw water to the heater 2 in the most front stage.

[0050] <Variation 3> In the above-described embodiment shown in FIGS. 1 and 2, the heating fluid for evaporating seawater in the heater 2 at the most upstream stage of the multiple-effect freshwater production system 1 does not necessarily have to be jacket cooling water, but may be steam from a boiler. [Explanation of symbols]

[0051] 1. Multiple-effect freshwater maker 2. Front-most heater 2´ Last stage heater 3 Condenser 10 Diesel engine (internal combustion engine) 14 Scavenging air cooler L2 Scavenging air cooling water supply line L3 Third heating fluid supply line L4 First heating fluid supply line L5 Raw water supply line L6 Steam cooling water supply line L8 Second heating fluid supply line

Claims

1. A water production system for desalination of seawater on a ship, comprising: a multiple-effect freshwater production system including a plurality of heaters that heat seawater with a heating fluid to generate steam, and a condenser that cools and condenses the steam, wherein the steam generated by the heaters in the preceding stages is supplied as a heating fluid from the heaters in the succeeding stages to the heaters in the succeeding stages, and the condenser condenses the steam generated by the heaters in the final stage; a scavenging air cooling water supply line for supplying the scavenging air cooler with scavenging air cooling water for cooling the scavenging air supplied to the marine internal combustion engine; a first heating fluid supply line connected to the scavenging air cooling water supply line, for supplying at least a portion of the scavenging air cooling water used to cool the scavenging air in the scavenging air cooler to the last-stage heater as a heating fluid; A water production system comprising:

2. The water production system according to claim 1 , wherein the scavenging air cooling water is fresh water.

3. 3. The fresh water production system according to claim 1, wherein the heater at the most upstream stage of the fresh water production system is configured so that jacket cooling water used to cool the internal combustion engine is supplied as a heating fluid to the heater.

4. 4. The freshwater generating system according to claim 3, further comprising a second heating fluid supply line connected to the first heating fluid supply line for supplying a portion of the scavenging air cooling water flowing through the first heating fluid supply line to a heater in a most upstream stage of the freshwater generating system as a heating fluid.

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