Water making system

Abstract

The invention provides a water generation system capable of effectively utilizing waste heat of scavenging air cooling water. The present invention is a fresh water system (1) for desalinating seawater contained in a ship, the fresh water system being provided with: a fresh water device (2) provided with a heater (3) for heating and evaporating seawater, and a condenser (4) for cooling and condensing steam generated by evaporation of seawater; a scavenging air cooler (14) configured to be capable of cooling scavenging air supplied to an internal combustion engine (diesel engine (10)) for a ship by heat exchange with scavenging air cooling water; and a feed water heater (5) configured to be capable of heating the seawater supplied to the heater (3) by heat exchange with at least a portion of the scavenging air cooling water discharged from the scavenging air cooler (14).

Description

Technical Field

[0001] The present invention relates to a fresh water system for desalinating seawater, and more particularly to a fresh water system for desalinating seawater using waste heat from an internal combustion engine such as a diesel engine of a ship's main engine. Background Art

[0002] In the past, ships have been producing fresh water by utilizing the waste heat from internal combustion engines such as diesel engines mounted on the ships as a heat source and evaporating seawater extracted from the sea under reduced pressure such as vacuum. For example, the fresh water generator described in Patent Document 1 guides scavenging air cooling water supplied to the diesel engine for scavenging air cooling to the fresh water generator, and utilizes the waste heat of the scavenging air cooling water for evaporating seawater in the fresh water generator. In the fresh water generator, seawater is evaporated by heat exchange with the scavenging air cooling water, and the generated steam is cooled and condensed, thereby desalinating the seawater.

[0003] [Prior Technical Literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent No. 4409546 Summary of the invention

[0006] [Technical problem to be solved by the invention]

[0007] However, the temperature of the scavenging air cooling water used for scavenging air cooling is about 60°C when the scavenging air cooling water is clean water, and is generally lower when the scavenging air cooling water is seawater than when it is clean water. In the fresh water generator, although the seawater is evaporated under reduced pressure, it is difficult to evaporate the seawater efficiently with the scavenging air cooling water at about 60°C. Therefore, when the waste heat of the scavenging air cooling water is used as the main heat source for the fresh water generator, there is a technical problem that the performance of the fresh water generator is low due to insufficient heat required to obtain a sufficient amount of fresh water (clean water). Alternatively, there is a technical problem that a larger heat transfer area is required during heat exchange of the scavenging air cooling water in order to obtain a sufficient amount of fresh water (clean water), resulting in a large-scale fresh water generator.

[0008] The present invention is proposed with a view to solving the above-mentioned technical problems, and its object is to provide a water making system which can effectively utilize the waste heat of scavenging air cooling water.

[0009] [Technical means]

[0010] The present invention, in order to solve the above-mentioned technical problems, is mainly based on the fresh water generation system described in the following Item 1.

[0011] Item 1. A fresh water system for desalinating seawater taken into a ship, comprising:

[0012] a water generating device including a heater for heating and evaporating seawater and a condenser for cooling and condensing steam generated by evaporation of the seawater;

[0013] a scavenging air cooler configured to cool scavenging air supplied to a marine internal combustion engine by heat exchange with scavenging air cooling water; and

[0014] A feedwater heater is configured to heat seawater supplied to the heater by heat exchange with at least a portion of the scavenging air cooling water discharged from the scavenging air cooler.

[0015] In addition, the water generation system of the present invention, as a preferred embodiment of the water generation system described in the above Item 1, includes the water generation system described in the following Item 2.

[0016] Item 2. The water production system according to Item 1, wherein the condenser is configured to cool the steam generated by evaporation of the seawater by heat exchange with the seawater taken into the ship;

[0017] The seawater heat-exchanged with the steam in the condenser is heated in the feedwater heater.

[0018] In addition, the water generation system of the present invention, as a preferred embodiment of the water generation system described in the above Items 1 and 2, includes the water generation system described in the following Item 3.

[0019] Item 3. The fresh water generation system according to Item 1 or 2, wherein the scavenging air cooling water is clean water.

[0020] In addition, the water generation system of the present invention includes a water generation system described in the following Item 4 as a preferred embodiment of the water generation system described in Items 1 to 3 above.

[0021] Item 4. The fresh water generation system according to any one of Items 1 to 3, wherein the heater is configured to heat the seawater by heat exchange with jacket cooling water that has been used for cooling the internal combustion engine.

[0022] [Effects of the invention]

[0023] The fresh water generation system of the present invention can effectively utilize the waste heat of the scavenging air cooling water to improve the performance of the fresh water generation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic configuration diagram of a water generation system according to an embodiment of the present invention.

[0025] Description of Reference Numerals

[0026] 1: Water making system

[0027] 2: Water making device

[0028] 3: Heater

[0029] 4: Condenser

[0030] 5: Feedwater heater

[0031] 6: Seawater supply channel

[0032] 7: Seawater inlet channel

[0033] 10: Diesel engine (internal combustion engine)

[0034] 11: Booster

[0035] 12: Turbine

[0036] 13: Compressor

[0037] 14: Scavenging air cooler

[0038] 15: First circulation channel

[0039] 16: First diversion channel

[0040] 17: Second circulation channel

[0041] 18: Second diversion channel

[0042] 19: Pump

[0043] 20, 23, 26, 28: Flow control valve

[0044] 21, 24: Cooler

[0045] 22: Circulation pump

[0046] 25, 27: Temperature sensor DETAILED DESCRIPTION

[0047] The embodiments of the present invention are described below with reference to the drawings. The water making system of the present invention utilizes waste heat from an internal combustion engine of a main engine that generates propulsion in a ship to desalinate seawater in a water making device, thereby improving the performance of the water making device. The internal combustion engine is, for example, a diesel engine.

[0048] Figure 1 The schematic diagram of the fresh water system 1 according to the embodiment of the present invention includes at least a fresh water generator 2 including a heater 3 and a condenser 4 , a scavenging air cooler 14 for cooling scavenging air supplied to a diesel engine 10 , and a feed water heater 5 .

[0049] 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. The diesel engine 10 circulates cooling water (jacket cooling water) for cooling the diesel engine 10 through the first circulation passage 15 .

[0050] The first circulation channel 15 is a pipeline for supplying jacket cooling water to the diesel engine 10. The jacket cooling water circulates in the first circulation channel 15 by driving the pump 19. A flow regulating valve 20 and a cooler 21 are connected to the first circulation channel 15. The flow regulating valve 20 regulates the flow of the jacket cooling water supplied to the diesel engine 10. The flow regulating valve 20 may also be provided with a flow meter. The cooler 21 cools the jacket cooling water discharged from the diesel engine 10 and becoming high temperature. The cooler 21 is, for example, a heat exchanger, and cooling water is supplied to the cooler 21 from a central cooler. In the cooler 21, the jacket cooling water is cooled by heat exchange with the cooling water.

[0051] The supercharger 11 supplies scavenging air to the diesel engine 10. The supercharger 11 includes a turbine 12 and a compressor 13. The turbine 12 is driven by exhaust gas discharged by the diesel engine 10 when the main fuel is burned. The compressor 13 compresses external air by the rotational power of the turbine 12. The supercharger 11 supplies the compressed external air to the diesel engine 10 as scavenging air.

[0052] The scavenging air cooler 14 cools the scavenging air supplied from the supercharger 11 to the diesel engine 10. The scavenging air becomes high temperature due to adiabatic compression, so for the purpose of increasing the air density (weight per unit volume), the scavenging air is cooled in the scavenging air cooler 14 and then supplied to the diesel engine 10. The scavenging air cooler 14 is, for example, a heat exchanger, and the scavenging air cooler 14 circulates cooling water (scavenging air cooling water) for cooling the scavenging air through the second circulation passage 17. Clean water or seawater is used as the scavenging air cooling water.

[0053] The second circulation passage 17 is a pipeline for supplying scavenging air cooling water to the scavenging air cooler 14, and the scavenging air cooling water circulates in the second circulation passage 17 by the drive of the circulation pump 22. The second circulation passage 17 is connected to a flow regulating valve 23 and a cooler 24. The flow regulating valve 23 regulates the flow rate of the scavenging air cooling water supplied to the scavenging air cooler 14. The flow regulating valve 23 may also be provided with a flow meter. The cooler 24 cools the scavenging air cooling water that becomes high temperature after cooling the scavenging air in the scavenging air cooler 14. The cooler 24 is, for example, a heat exchanger, and cooling water is supplied to the cooler 24 from a central cooler. In the cooler 24, the scavenging air cooling water is cooled by heat exchange with the cooling water.

[0054] The water-generating device 2 heats seawater to generate steam, then separates the vapor and liquid, and generates fresh water by condensing the steam after the vapor-liquid separation. In the water-generating device 2, a reduced pressure (vacuum) state is maintained, for example, by a decompression means such as a water jet. The water-generating device 2 is not particularly limited as long as it is a device for desalinating seawater. The water-generating device 2 can be exemplified by, for example: a flash evaporation-type water-generating device (for example, Japanese Patent Publication No. 2009-90228), a plate-type water-generating device (for example, Japanese Patent Publication No. 9-299927), a multi-tube water-generating device (for example, Japanese Patent Publication No. 2013-166141), a membrane distillation-type water-generating device (for example, Japanese Patent Publication No. 6-7644), etc. The water-generating device 2 can be a single-effect evaporation-concentration device, or a multi-effect evaporation-concentration device with more than two effects.

[0055] In the fresh water generator 2, the heater 3 heats and evaporates the seawater introduced into the fresh water generator 2. The heater 3 supplies seawater as a raw material of fresh water through the seawater supply passage 6. The heater 3 is not particularly limited, and is, for example, a tubular heat exchanger. For example, jacket cooling water used for cooling the diesel engine 10 is supplied to the heater 3 as a heat source for evaporating the seawater, and this is not particularly limited. In the heater 3, the supplied seawater is heated by heat exchange with the jacket cooling water, and evaporates after the temperature rises. The steam generated by the evaporation of the seawater is supplied to the condenser 4.

[0056] The temperature of the jacket cooling water after cooling the diesel engine 10 is about 80° C. to 90° C. Therefore, the seawater can be heated by the jacket cooling water under reduced pressure to evaporate the seawater efficiently. Therefore, by using the jacket cooling water as the main heat source for fresh water generation in the fresh water generator 2, a sufficient amount of fresh water (clean water) can be obtained.

[0057] The heater 3 circulates the jacket cooling water after cooling the diesel engine 10 through the first branch channel 16. The first branch channel 16 is a pipeline that guides the jacket cooling water that has cooled the diesel engine 10 and has become high temperature to the heater 3. A part of the jacket cooling water is branched from the first circulation channel 15 through the first branch channel 16 and then flows back to the first circulation channel 15 through the heater 3.

[0058] The first branch channel 16 is connected to a temperature sensor 25 and a flow regulating valve 26. The flow regulating valve 26 regulates the flow rate of the jacket cooling water (the jacket cooling water supplied to the heater 3) branched from the first circulation channel 15 to the first branch channel 16. The flow regulating valve 26 may be provided with a flow meter. The temperature sensor 25 measures the temperature of the jacket cooling water supplied to the heater 3. Based on the temperature of the jacket cooling water detected by the temperature sensor 25, the flow rate of the jacket cooling water supplied to the heater 3 is regulated.

[0059] In the fresh water generator 2, the condenser 4 cools and condenses the steam generated by the evaporation of seawater. The condenser 4 is, for example, a tubular heat exchanger, but is not particularly limited thereto. The seawater drawn from the sea by the seawater inlet passage 7 and introduced into the ship is supplied to the condenser 4 as a heat source for condensing the steam, but is not particularly limited thereto. If the seawater drawn from the sea is introduced into the fresh water generator 2, the seawater is supplied to the condenser 4. In the condenser 4, the steam generated by the evaporation of the seawater is cooled by heat exchange with the seawater, and condensed after the temperature is lowered. The fresh water (distilled water) generated by the condensation of the steam is discharged to the outside of the fresh water generator 2 by a pump and then stored in a water storage tank.

[0060] After the seawater has undergone heat exchange with the steam in the condenser 4 , a portion is discharged to the outside of the ship system, and a portion is supplied to the heater 3 through the seawater supply passage 6 as raw seawater.

[0061] The feedwater heater 5 is provided in the seawater supply passage 6, and heats the seawater supplied from the condenser 4 to the heater 3. By raising the temperature of the seawater, which is the raw material of fresh water, and supplying it to the heater 3, the amount of heat (sensible heat) required to heat the seawater in the heater 3 to evaporate can be reduced, and the amount of heat (latent heat) required for evaporation of the seawater that contributes to the actual amount of water produced can be increased. In this way, the thermal efficiency of the heater 3 can be improved, the performance of the water production device 2, such as the increase in the amount of water produced, can be improved, and the water production device 2 can be miniaturized.

[0062] The feed water heater 5 is, for example, a tubular heat exchanger, but is not particularly limited thereto. The scavenging air cooling water used for cooling the scavenging air is supplied to the feed water heater 5 as a heat source for raising the temperature of the seawater. In the feed water heater 5, the supplied seawater is heated by heat exchange with the scavenging air cooling water, and the temperature is raised. The seawater having the raised temperature is supplied to the heater 3 as raw seawater.

[0063] In the case where the scavenging air cooling water is clean water, the temperature of the scavenging air after cooling is about 60°C. On the other hand, in the case where the scavenging air cooling water is seawater, the temperature of the scavenging air after cooling is generally about 45°C to 50°C. In the case where the scavenging air cooling water is seawater, if the temperature after cooling the scavenging air becomes too high, the generation of scale becomes a significant concern. In the heat exchanger through which the scavenging air cooling water circulates, if a large amount of scale adheres, the performance of the heat exchanger will be reduced. Therefore, in the case where the scavenging air cooling water is seawater, the temperature after cooling the scavenging air is limited to 45°C to 50°C. Accordingly, in order to increase the temperature of seawater, which is a raw material of fresh water, as much as possible through the feed water heater 5 and supply it to the heater 3, it is preferred that the scavenging air cooling water is clean water.

[0064] The feed water heater 5 circulates the scavenging air cooling water after cooling the scavenging air through the second branch channel 18. The second branch channel 18 is a pipeline that guides the scavenging air cooling water that has cooled the scavenging air to a high temperature to the feed water heater 5. At least a part of the scavenging air cooling water is diverted from the second circulation channel 17 through the second branch channel 18 and then flows back to the second circulation channel 17 through the feed water heater 5.

[0065] The second circulation passage 17 is connected to a temperature sensor 27 and a flow regulating valve 28. The flow regulating valve 28 regulates the flow rate of the scavenging air cooling water (scavenging air cooling water supplied to the feed water heater 5) branched from the second circulation passage 17 to the second branch passage 18. The flow regulating valve 28 may also be provided with a flow meter. The temperature sensor 27 measures the temperature of the scavenging air cooling water supplied to the feed water heater 5. Based on the temperature of the scavenging air cooling water detected by the temperature sensor 27, the flow rate of the scavenging air cooling water supplied to the feed water heater 5 is regulated.

[0066] According to the fresh water generation system 1 of the above-described embodiment, at least a portion of the scavenging air cooling water used for cooling the scavenging air of the diesel engine 10 is supplied to the feed water heater 5, and in the feed water heater 5, the temperature of the raw seawater is increased by heat exchange between the scavenging air cooling water and the raw seawater supplied to the heater 3 of the fresh water generation device 2. Thus, raw seawater of a higher temperature is supplied to the heater 3 of the fresh water generation device 2, and the raw seawater can be efficiently heated and evaporated in the heater 3, so that the performance of the fresh water generation device 2 can be improved.

[0067] As described above, in the fresh water generation system 1 of the above-described embodiment, the performance of the fresh water generation device 2 is improved by recovering the waste heat of the scavenging air cooling water to the raw seawater, and the waste heat of the scavenging air cooling water can be effectively utilized.

[0068] Furthermore, in the fresh water generation system 1 of the above-mentioned embodiment, at least a part of the jacket cooling water used for cooling the diesel engine 10 is supplied to the heater 3 of the fresh water generation device 2, and the raw seawater is evaporated by heat exchange between the jacket cooling water and the raw seawater in the heater 3. Thus, the fresh water generation system 1 of the above-mentioned embodiment can effectively utilize the waste heat of the jacket cooling water.

[0069] The embodiments of the water generation system of the present invention are described above, but the above embodiments are only exemplary and not restrictive. Therefore, the water generation system of the present invention is not limited to the above embodiments, and various modifications can be made as long as they do not depart from the scope of the present invention.

[0070] For example, in the above-described embodiment, the feed water heater 5 is provided outside the fresh water generator 2 , but may be provided inside the fresh water generator 2 .

[0071] For example, in the above-mentioned embodiment, the fresh water generator 2 may include a preheater, which is a tubular heat exchanger. Specifically, a portion of the seawater condensed with steam in the condenser 4 of the fresh water generator 2 is supplied to the preheater and preheated by heat exchange with the steam, and the preheated seawater is supplied to the feed water heater 5, and then, can be supplied to the heater 3 as raw seawater.

[0072] For example, in the above-described embodiment, the main heat source for evaporation of seawater in the heater 3 of the fresh water generator 2 is not necessarily the waste heat of the jacket cooling water, but may be steam from a boiler.

Claims

1. A fresh water system for desalinating seawater taken into a ship, the fresh water system comprising: a water generating device including a heater for heating and evaporating seawater and a condenser for cooling and condensing steam generated by evaporation of the seawater; a scavenging air cooler configured to cool scavenging air supplied to a marine internal combustion engine by heat exchange with scavenging air cooling water; and The feedwater heater is configured to heat the seawater supplied to the heater by heat exchange with at least a portion of the scavenging air cooling water discharged from the scavenging air cooler.

2. The water generation system according to claim 1, wherein: The condenser is configured to cool steam generated by evaporation of seawater by heat exchange with the seawater taken into the vessel; The seawater heat-exchanged with the steam in the condenser is heated in the feedwater heater.

3. The water generation system according to claim 1, wherein: The scavenging air cooling water is clean water.

4. The water generation system according to claim 1, wherein: The heater is configured to be capable of heating seawater through heat exchange with jacket cooling water that has been used for cooling the internal combustion engine.

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