JP2000325942A - Device for desalting salt water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for desalting salt water by using solar heat, decreasing electric power consumption extremely and being driven by only solar batteries or by solar batteries and storage batteries to eliminate the need for external electric power. SOLUTION: In a device for desalting salt water by heating and evaporating it, mainly comprising a heat source device, a salt water tank 1, evaporative concentrators 3-6, and a condenser 8, the heat source device consists of a heat collector 11, heat exchangers 12 for heating, each mounted in the evaporative concentrator to transmit solar heat in the daytime, a heat exchange 13 for cooling, mounted in the salt water tank 1 to transmit heat of radiational cooling in the nighttime, circulation passages 41-44 to connect the heat exchangers and the heat collector, and an internal heat transfer medium, a heat exchanger for the condenser 8 is installed in the salt water tank 1 and is connected to the evaporative concentrator 3 through a passage 3 supplying the salt water, and a pump 9 for the heat transfer medium, driven by solar batteries, may be installed in the circulation passage connecting the heat exchangers 12 for heating with the heat collector 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a salt water desalination apparatus, and more particularly to a salt water desalination apparatus for obtaining fresh water from salt water such as seawater by solar heat.

[0002]

2. Description of the Related Art Conventionally, by heating water containing salt such as seawater to evaporate water and condense the water vapor,
A salt water desalination apparatus for obtaining fresh water which is water free of salt is a well-known apparatus. Usually, the apparatus heats and evaporates the salt water in the low-pressure part using the generated steam, so that it is often a so-called multiple effect. The electricity used in the salt water desalination apparatus includes a motor such as a vacuum generator (vacuum pump or water jet pump), a concentrated salt water discharge pump and a fresh water discharge pump, and a small capacity motor such as a switching valve drive motor. There is a problem that a power supply and a control power supply are required, and the amount of power used increases.

[0003]

DISCLOSURE OF THE INVENTION In view of the above prior art, the present invention provides a salt water freshwater utilizing solar heat, in which the power consumption is extremely reduced, the solar cell is driven solely by a solar cell or a solar cell and a storage battery, and external power is not required. It is an object to provide a chemical conversion device.

[0004]

In order to solve the above-mentioned problems, the present invention provides a heat source device, a salt water tank, an evaporator,
In a salt water desalination apparatus that heats and evaporates salt water to produce fresh water using a condenser as a main component, the heat source device is a heat collector and a heating device that transmits daytime solar heat installed in the evaporator and concentrator. Heat exchanger, a cooling heat exchanger installed in the salt water tank for transmitting radiant cooling heat at night, a circulation path connecting these heat exchangers and the heat collector, and an internal heat transfer medium. And a heat exchanger for a condenser is provided in the salt water tank, and the salt water tank and the evaporative concentrator are connected by a path for supplying salt water. . In the salt water desalination apparatus, a heat transfer medium pump driven by a solar cell may be provided in a circulation path connecting the heating heat exchanger and the heat collector.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the drawings. 1 to 3 show a flow configuration diagram of the salt water desalination apparatus of the present invention, and FIGS. 1 to 3 show a quadruple effect. In the figure, 1 is a salt water tank, 2A, 2B, 2C are preheaters, 3, 4, 5, and 6 are evaporative concentrators, 7 is a concentrated salt water tank, 8 is a condenser, 9 is a fresh water tank, and 10 is a deaerator. , 11
Is a heat collector, 12 is a heat exchanger for heating, 13 is a heat exchanger for cooling, 14 is a vacuum device, 15, 16, and 17 are water jet pumps, 18 to 20 are pumps, 21 is an expansion tank, and 22 is a lower part. A tank, 24-28 are valves, and 29 is a three-way valve.

First, the salt water desalination operation will be described with reference to FIG. 1. An external salt water a is supplied from a pipe 30 to a salt water tank 1 and used for cooling the concentrator 8. The salt water a in the salt water tank 1 is sucked into the device due to the difference between the atmospheric pressure and the internal pressure of the salt water desalination device, passes through the pipe 31, passes through the preheaters 2A, 2
In B and 2C, it is heated by the steam from each of the evaporative concentrators 4, 5, and 6, introduced into the first-stage evaporative concentrator 3, heated by the heat transfer medium from the solar heat collector 11, and evaporated and concentrated. You. The generated steam enters the heat exchanger of the second-stage evaporator 4 from the pipe 36, heats the salt water outside the heat exchanger, partially liquefies it, enters the preheater 2C, and heats the feed salt water. Liquefies and enters the lower preheaters 2B and 2A. On the other hand, the brine concentrated in the first stage is supplied from the pipe 32 to the second stage evaporator 4
And heated by the above-mentioned generated steam to be evaporated and concentrated.

[0007] The steam generated in the second-stage evaporative concentrator 4 enters the heat exchanger of the third-stage evaporative concentrator 5 through a pipe 37 and is generated in the third-stage evaporative concentrator 5. The steam enters the heat exchanger of the fourth-stage evaporative concentrator 6 through the pipe 38 and performs the same evaporative concentration. The salt water concentrated in the second stage 4 enters the third stage evaporative concentrator 5 through the pipe 33, and the salt water concentrated in the third stage passes through the tube 34 into the fourth stage evaporative concentrator 5. 6, is evaporated and concentrated, and then enters a concentrated salt water tank 7. The concentrated salt water b is intermittently discharged by a pump based on a signal from a liquid level sensor or the like. The vapor generated in the fourth stage evaporator 6 enters the condenser 8 through the pipe 39, is cooled and liquefied,
The fresh water c stored in the fresh water tank 9 is intermittently discharged by a pump based on a signal from a liquid level sensor or the like.

[0008] The dissolved gas contained in the salt water is discharged from the evaporators 3 to 6 and finally passes through the vapor systems 36 to 39 and collects in the condenser 8. This gas is discharged from the condenser 8 by the vacuum device 14. The salt water “a” in the salt water tank 1 cools the condenser 8 and is heated by itself and becomes an upward flow, causing natural convection. For this reason, the condenser 8 is preferably provided at a lower part in the salt water tank 1. As long as solar heat can be secured, desalination operation is possible. During this time, heat of condensation is released to the salt water tank 1. The capacity of the salt water tank 1 is determined in consideration of this temperature rise. In addition, even during the desalination operation, the salt water tank 1 is cooled by outside air from the outside. (The temperature rises because there is more heat of condensation.)

[0009] In the salt water desalination apparatus, the heat source device is operated as follows. In the solar heat collector 11, the heat transfer medium d (water or antifreeze) is heated by the solar heat and becomes an ascending flow, and flows from the pipe 41 to the heat exchanger 1 of the first-stage evaporative concentrator 3.
2 where it releases heat and is cooled down into a downflow and enters the lower part of the collector 11 through the pipe 42. As described above, natural circulation is possible, but forced circulation may be performed by the pump 19. In this case, solar cell driving is preferable. As described above, in the salt water desalination operation using the solar heat, the temperature of the salt water a in the salt water tank 1 is increased. Therefore, at night when the salt water desalination operation is not performed, the valve 25 is closed, the flow path is switched, and the solar heat collection is performed. The tubes 43 and 44 allow the heater 11 and the cooling heat exchanger 13 of the salt water tank 1 to communicate with each other, where natural circulation is performed.
The water is heated in the salt water tank 1 and becomes an upward flow.
Is cooled by nighttime cool air and sky radiation, and becomes a downward flow. If there is room for electricity, forced circulation is also possible with the pump 20.

FIG. 2 shows another flow diagram of the salt water desalination apparatus of the present invention. FIG. 2 is different from FIG. 1 in that FIG.
The salt water tank 1 is a closed tank, and the salt water tank 1 is depressurized by the vacuum device 14 using a water jet pump 16 to release dissolved gas from the salt water. In this case, depending on the pressure of the salt water tank 1, the pump 8 is required to supply the salt water to the desalination apparatus. Other operations are the same as those in FIG. FIG. 3 is a view showing a state in which the salt water a
Is introduced through a vacuum deaerator 10, and the pressure is reduced by a water jet pump 17 by a vacuum device 14, a dissolved gas is released from the salt water, and then supplied to a salt water tank. In the heat source device, a tank 22 is provided below the heat collector 11 and is connected to the expansion tank 21 by a pipe 45. If there is a possibility of freezing during cooling at night, the upper part of the expansion tank 21 is connected to the heat collector. When the valve 28 is opened and communicated between the lower tanks 22, the medium drops and the cooling can be completed.

[0011]

According to the present invention, in a salt water desalination apparatus for obtaining fresh water from salt water by solar heat, the power consumption is extremely reduced, and it is possible to operate the solar cell alone or the solar cell and the storage battery to eliminate external power. did it.

[Brief description of the drawings]

FIG. 1 is a flow configuration diagram showing an example of a salt water desalination apparatus of the present invention.

FIG. 2 is a flow configuration diagram showing another example of the salt water desalination apparatus of the present invention.

FIG. 3 is a flow configuration diagram showing another example of the salt water desalination apparatus of the present invention.

[Explanation of symbols]

1: salt water tank, 2A, 2B, 2C: preheater, 3-6:
Evaporation concentrator, 7: concentrated salt water tank, 8: condenser, 9: fresh water tank, 10: deaerator, 11: collector, 12: heating heat exchanger, 13: cooling heat exchanger, 14: Vacuum equipment, 15
-17: water jet pump, 18-20: pump, 2
1: expansion tank, 22: lower tank

Claims (2)

[Claims] 1. A salt water desalination apparatus for producing fresh water by heating and evaporating salt water, comprising a heat source device, a salt water tank, an evaporator and a condenser as main components, wherein the heat source device comprises: a collector; Heating heat exchanger installed in the vessel to transmit daytime solar heat, cooling heat exchanger installed in the salt water tank to transmit radiant cooling heat at night, and these heat exchangers and collectors And a heat transfer medium inside, a heat exchanger for a condenser is provided in the salt water tank, and the salt water tank and the evaporative concentrator are connected by a path for supplying salt water. Characteristic solar water desalination equipment. 2. A solar water-utilized salt water freshwater according to claim 1, wherein a pump for a heat carrier medium driven by a solar cell is provided in a circulation path connecting the heat exchanger for heating and the heat collector. Device.