JPH10277535A - Seawater-desalting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form fresh water while utilizing the cold heat of pure ice precipitating ice lumps containing no impurities from seawater. SOLUTION: A pure ice making apparatus 11 forming ice lumps from seawater operates a freezing device 12 utilizing inexpensive excessive power such as night power and seawater is cooled by an evaporator 121 on a cooling side not only to form pure ice high in purity from seawater but also to separate highly conc. seawater and conc. seawater is sent to a seawater treatment apparatus 13 and pure ice is supplied to an ice storing hot water tank 14. The seawater treatment apparatus 13 forms salt from the supplied conc. seawater and pure ice high in purity is stored in the ice storing hot water tank 14. The stored pure ice is melted by the condensed water from a fresh water storage tank 15 to be stored in the ice storing hot water tank 14. This water is supplied as the cold heat of a refrigerating stocker 16. Condensed water containing waste heat after the utilization of the cold heat in the refrigerating stocker 16 is stored in the fresh water storing tank 15. A condenser 122 on the radiation side of the freezing device 12 is attached to the fresh water storage tank 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seawater desalination system for treating seawater to make it desalinated.

[0002]

2. Description of the Related Art Evaporation, reverse osmosis, electrodialysis and the like have been put to practical use as a method for treating seawater to make it desalinated. In addition, although not practically used, there are a freeze-thaw method (freezing method), a pervaporation method, and the like. (Reference material: 1996 edition
Japan's water resources (Water Resources White Paper), National Land Agency) The evaporation method in the above-mentioned seawater desalination system is to evaporate by heating seawater or spraying seawater on an evaporator to evaporate. In this method, generated steam is cooled to obtain fresh water. The reverse osmosis method uses a semi-permeable membrane that allows water to permeate but does not allow salt to permeate,
In this system, fresh water is obtained by applying pressure to one side of a semi-permeable membrane containing seawater to allow only water to permeate.

The above-mentioned method is a seawater desalination method that has been put into practical use. Among the methods that have not been put into practical use, the freeze-thaw method involves growing pure ice crystals in seawater and then floating ice crystals in the seawater. Only to separate and melt. This system is a system that separates seawater into freshwater and concentrated seawater using the cold heat of LNG.

[0004]

Among the above-mentioned seawater desalination systems put into practical use, the evaporation method heats and evaporates seawater to generate steam, and the steam is cooled to reduce the energy consumption cost. Therefore, there is a problem that desalination cost is high. The seawater desalination method using a semi-permeable membrane, like the reverse osmosis method, reduces the cost of freshwater, but requires a lot of plant area, maintenance costs, etc. There is a problem that a two-step desalination process is required. In addition, the freeze-thaw method, which is an impractical method, does not use the surplus power such as nighttime power or private power generation to inexpensively separate seawater into pure ice and concentrated seawater, but simply uses the cold heat of LNG. Just do
Simply freezing seawater causes the following problems.

[0005] Usually, as long as water is a liquid, various gases,
It dissolves liquids and solids sufficiently, mixes with various liquids and solids, and dissolves or mixes each substance very well, but when it comes to ice, it dissolves all solutes and mixtures at the molecular level. It is known to eliminate and grow as crystals of pure ice molecules. However, at the level of an ice block, it becomes very difficult to grow pure ice as a crystal, because it becomes an ice block containing a solute and a mixture containing seawater between ice crystal crystals. There's a problem.

The present invention has been made in view of the above circumstances, and provides a seawater desalination system that generates freshwater while utilizing the cold heat of pure ice in which ice blocks containing no impurities are precipitated from seawater. That is the task.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, a first invention is a pure ice making apparatus for cooling seawater and producing pure ice and concentrated seawater from the cooled seawater. And storing the pure ice generated by the pure ice making apparatus, melting the stored pure ice and storing it as cold water, and utilizing the cold water stored in the ice thermal storage tank as cold heat. The tank includes a condensed water containing waste heat that has ended, and a freshwater storage tank that stores the condensed water as freshwater.

In a second aspect of the present invention, a concentrated seawater generated by a pure ice making device is introduced, and a seawater treatment device for generating salt from the concentrated seawater is provided.

According to a third aspect of the present invention, there is provided a refrigerating apparatus which is operated with surplus electric power, the seawater supplied to the pure ice making apparatus is cooled on the evaporator side of the refrigerating apparatus, and the freshwater in the freshwater storage tank is cooled on the condenser side. It is intended to warm up.

[0010] A fourth aspect of the present invention is to supply the ice heat storage tank with fresh water from the fresh water storage tank as condensate to melt the pure ice.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 11 denotes a pure ice making device for generating ice blocks from seawater, which will be described in detail later. The pure ice making device 11 uses a cheap surplus electric power such as nighttime electric power or privately generated electric power to form a refrigeration apparatus 12. In operation, the seawater is cooled by the evaporator 121 on the cooling side, and pure ice having high purity is generated from the seawater, and concentrated seawater concentrated at a high concentration is generated. Then, the generated concentrated seawater is sent to the seawater treatment device 13, and the pure ice is supplied to the ice heat storage water tank 14.

The seawater treatment device 13 generates salt from the supplied concentrated seawater and recovers it as salt. On the other hand, pure ice of high purity is stored in the ice heat storage water tank 14. The pure ice in the ice storage water tank 14 is melted by condensing water from the fresh water storage tank 15 and stored in the ice storage water tank 14 as cold water at a constant temperature (about 4 ° C.). This cold water is supplied for cooling the cold storage 16. This cold water is used not only for the refrigerated warehouse 16 but also for various types of cooling.

Condensed water containing waste heat that has been used in the cold storage 16 is stored in a fresh water storage tank 15. The freshwater storage tank 15 has a condenser 122 on the heat radiation side of the refrigerating device 12.
Is mounted to warm the fresh water in the water storage tank 15 and to cool the condenser 122 to improve the efficiency of the refrigerating device 12. Note that the fresh water in the fresh water storage tank 15 is used for various types of water or used as condensate for melting the pure ice in the ice heat storage water tank 14 as described above.

Next, a schematic configuration of the pure ice making apparatus 11 will be described with reference to FIG. In FIG. 2, reference numeral 31 denotes a tank into which seawater 41 is introduced from a seawater supply pipe (not shown).
An air diffuser 32 is disposed at the inner bottom of the unit 1. Air is supplied to the air diffuser 32 from an air pump 33, and bubbles 42 are continuously blown out from the air diffuser 32. Numeral 34 denotes a rotating belt. Part of the rotating belt 34 is submerged in seawater, and the other part is exposed above the water surface of the tank 31. 35a, 35b,
35c is a roller, at least one of which is formed as a drive roller.

A cooling section 36 and a heater section 37 are disposed inside the rotating belt 34. The cooling section 36 is provided inside the rotating belt 34 submerged in seawater. Each is disposed inside the belt 34. 3
8 is a hot air heater, 39 is an ice block made of pure ice, 40 is an ice generator, 121 is an evaporator of the refrigeration system 12, and the evaporator 121 cools seawater.

In the pure ice making apparatus constructed as described above, the air pump 33 is rotated so that the air bubbles 42 are continuously blown out by the air diffuser 32. At the same time as the seawater is agitated by the bubbles 42, the seawater is kept at 0 ° C. without being supercooled. Ice crystals grow on the surface of the cooling unit 36 while removing impurities by continuous blowing of bubbles 42. The grown ice crystals are conveyed by the rotating belt 34, and when they reach the position of the heater 37, the ice is warmed by the heater 37 and the hot air heater 38. In particular, a part of the surface of the ice is melted into water, The impurities adhering to the surface are washed away by the water and flow off. As a result, pure ice blocks 39 are removed from the rotating belt 34, and the ice blocks 39 are continuously generated. The ice blocks 39 thus generated are stored in the ice heat storage water tank 14 shown in FIG.

In the embodiment of the present invention configured as described above, a portion where only pure ice grows is provided,
A large ice block can be precipitated there,
It is possible to use not only the cold heat of the LNG but also the cold heat generated by a refrigerating apparatus that uses surplus power such as nighttime power or private power generation. In addition, the separated pure ice is stored in an ice heat storage water tank, and after using the cold heat in a large commercial refrigerator or an air conditioner, the cold water can be used as fresh water, and further, salt is generated from the concentrated seawater by a seawater treatment device. be able to.

[0018]

As described above, according to the present invention,
There is an effect that seawater is separated into pure ice and concentrated seawater, and freshwater is generated using the cold heat of the pure ice, while salt can be generated from the concentrated seawater. Further, according to the present invention, since cold heat and fresh water can be used simultaneously, in an area where district heating and cooling is introduced, for example, not only energy saving but also effective use of water can be achieved.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a seawater desalination system showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a pure ice making apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Pure ice making equipment 12 ... Refrigeration equipment 13 ... Seawater treatment equipment 14 ... Ice heat storage water tank 15 ... Fresh water storage tank 16 ... Refrigerated warehouse

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[Procedure amendment]

[Submission date] January 8, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

A cooling section 36 and a heater section 37 are disposed inside the rotating belt 34, and the evaporating section of the refrigerating apparatus 12 shown in FIG.
The cooling unit 36 cooled by the heater 121 is inside the rotating belt 34 submerged in seawater, and the heater unit 37 is
Are respectively disposed inside the rotating belt 34 on the upper side.
38 warm air heater, 39 is a pure ice ice mass, 40 is the ice generating unit.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (4)

[Claims] 1. A pure ice making device that cools seawater to produce pure ice and concentrated seawater from the cooled seawater, and stores pure ice generated by the pure ice making device and stores the pure ice stored therein. An ice storage tank that melts ice and is stored as cold water, and a freshwater storage tank that stores condensate containing waste heat that has finished using cold water stored in this ice storage tank as cold heat and stores it as fresh water. Including seawater desalination system. 2. The seawater desalination system according to claim 1, wherein a concentrated seawater generated by the pure ice making device is introduced, and a seawater treatment device for generating salt from the concentrated seawater is provided. 3. A refrigeration unit operated by surplus electric power is provided.
The seawater desalination system according to claim 1, wherein seawater supplied to the pure ice making device is cooled on an evaporator side of the refrigerating device, and freshwater in a freshwater storage tank is warmed on a condenser side. 4. The seawater desalination system according to claim 1, further comprising supplying pure water from the freshwater storage tank to the ice heat storage tank as condensate to melt the pure ice.