JPH10230246A - Seawater desalination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seawater desalination device capable of being miniaturized and surely removing salt matter under high power efficiency. SOLUTION: This seawater desalination device is provided with a seawater tank 10 for storing seawater, a seawater heating section 20 for heating seawater supplied from the seawater tank up to the temp. lower than the b.p. of seawater, an aspirator 35 for sucking with negative pressure generated at a branched port of the side surface of a pipe by circulating the seawater through the pipe by a motor-driven pump, a flash section 30 for evaporating seawater supplied from the seawater heating section 20 by reducing the pressure by the aspirator and housing a condenser 31, through which a cooling liquid is circulated, and a thermoelement 15 for cooling the cooling liquid with endothermic by Peltier effect. A sealing cap 26 to be a partition to the flash section 30 is provided on the seawater heating section 20 and a nozzle 50 communicated with the flash section 30 and having a wet body attached to the tip is provided in the sealing cap.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a seawater desalination apparatus for obtaining freshwater by evaporating seawater and condensing it in a condenser.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 2-2145 discloses this type of apparatus.
No. 86, the seawater is led to a condenser for heat exchange with water vapor, then to a solar pond that absorbs and accumulates solar heat to heat the seawater, and then to a flash chamber under reduced pressure to evaporate the water. A seawater desalination apparatus that obtains freshwater by condensing the steam with a condenser is well known. According to Japanese Patent Application Laid-Open No. 7-108101, heated seawater is increased in surface area through a porous substance, evaporated under reduced pressure, and then condensed.
A method for suppressing seawater contamination and efficiently desalinating is disclosed.

[0003]

However, the former device is intended to efficiently produce fresh water by utilizing the heat stored in the solar pond as a heat source for evaporating and condensing seawater moisture. However, it is based on a large-scale desalination plant or desalination plant installed on the coast. Also, the latter device is intended to pump seawater with a pump, reduce the pressure with a vacuum pump and evaporate through a porous material, and in any case, is based on a large-sized desalination device.

[0004] On the other hand, a device for evaporating and condensing under reduced pressure suitable for obtaining fresh water under power saving required in a stricken area where water supply is cut off due to a disaster, an isolated island or a ship without power supply, etc. is particularly proposed. It has not been. The seawater desalination method using the reverse osmosis membrane does not require electric power, but it cannot remove the salt sufficiently after several filtration steps, and requires maintenance and inspection work due to clogging of the reverse osmosis membrane. However, there is a disadvantage that the final cost increases.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a seawater desalination apparatus which can be reduced in size and can reliably remove salt under high power efficiency.

[0006]

According to the present invention, there is provided a seawater desalination apparatus for obtaining seawater by evaporating seawater and condensing the seawater in a condenser. A seawater tank, a seawater heating chamber that heats the seawater supplied from this seawater tank to a temperature lower than the boiling point, and a motor-driven pump that circulates the water flow through the pipes and suctions by the negative pressure generated at the branch on the side of the pipe A suction chamber, a flash chamber in which a condenser for circulating the cooling liquid, which evaporates the seawater supplied from the seawater heating chamber by being depressurized by the suction apparatus, and heat absorption by the Peltier effect of the cooling liquid. A thermoelectric element for cooling is provided, and in the seawater heating chamber, a hermetic lid serving as a partition from the flash chamber is provided. Junkarada characterized in that is provided with a nozzle mounted.

[0007] The flash chamber is depressurized by a suction device using a circulating water flow, and the cooling liquid of the condenser is cooled by a thermoelectric element utilizing the Peltier effect. Seawater heated to a temperature lower than the boiling point of water in the seawater heating chamber and set in consideration of the power efficiency including the suction source becomes mist in the flash chamber that has infiltrated the felt and was decompressed. It is sprayed and the water evaporates rapidly due to its low boiling point in vacuum and is desalinated by condensing on contact with the condenser.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A seawater desalination apparatus according to an embodiment of the present invention will be described with reference to FIGS. This desalination device can store, for example, about 40 liters of seawater,
And a seawater tank 10 having a lid 10b having a vent hole.
And a seawater heating chamber 2 that is placed on the base 21 and heats seawater supplied from the seawater tank 10 through the pipe 12.
0, a flash chamber 30 in which a condenser 31 formed of a pipe through which seawater heated in the seawater heating chamber is supplied and in which cooling water in which methanol is mixed as a cooling liquid is circulated, and a base 41 And a fresh water tank 40 provided with a drainage faucet 42, and a flush chamber 3
0 is sucked through a hose 39 and a cooling water tank 16 provided below the seawater tank 10 so as to radiate heat on one of the heat radiating surfaces 15b to thereby discharge the seawater tank 1
The thermoelectric element 15 by the Peltier effect which heats the seawater 10a in the inner space 0 and cools the cooling water by absorbing heat on the other heat absorbing surface 15a.
And The seawater tank 10, seawater heating chamber 20, flash chamber 30, and freshwater tank 40 are made of, for example, transparent heat-resistant glass, polycarbonate, or stainless steel.

A grid-like heater 19 is attached to the seawater tank 10 at an intermediate position above the thermoelectric element 15 so as to communicate vertically. The seawater 10a is heated to about 70 ° C. by the temperature controller 19a. Thermoelectric element 15
Has an input unit 15c for supplying DC power of about 200 W. The cooling water tank 16 is provided with a pump 17 that supplies cooling water cooled by the thermoelectric element 15 to the condenser 31 through a hose 32 and returns the cooling water through a hose 32a. A cock 11 is attached to the pipe 12, and a filter 13 such as activated carbon is detachably attached to an inlet of the cock 12 so that foreign matter is not supplied to the seawater heating chamber 20.

The seawater heating chamber 20 is cylindrical with an inner diameter of about 25 cm and a height of about 4 cm, and thus has a volume of about 2 liters. A heater 25 is disposed at the bottom, and the seawater 10a is heated to a temperature within a range of about 70 ° C. to 90 ° C. by a temperature control unit 25a. At the upper end of the seawater heating chamber 20, a stainless steel disk-shaped lid 26 having a thickness of about 5 mm serving as a partition from the flash chamber 30 is placed. The disk-shaped hermetic lid is provided with, for example, four nozzles 50 having four through holes 51 with an inner diameter of 1 to 1.5 mm in the diameter direction. As shown in FIG. 2, each of the nozzles 50 is formed into a pipe having a thread 52 formed on the outer peripheral surface, and screwed until the flange portion 53 comes into contact with the sealing lid 26. A Teflon cartridge 56 in which a cylindrical felt 55 having a diameter of about 3 mm and a height of about 3 cm as an infiltration body is stored in the nozzle 50 so as to expose the front end thereof is screwed up to the flange 53. I have. Note that the cartridge 56 may be detachably fitted to the nozzle 50. The shapes of the nozzles 50 and the felts 55 and the numbers thereof are set so as to contain the unevaporated seawater with respect to the degree of vacuum of the flash chamber 30 and to spray with high purity.

In front of the seawater heating chamber 20, the seawater is L
A faucet 23 for draining from a letter-shaped outlet pipe is attached. Further, a drain groove 26b communicating with the flash chamber 30 is formed in the sealing lid 26, and the lower end thereof is closed when the air pressure on the inlet side is lower than the outlet side, and the inlet side is loaded with a predetermined amount. A similar faucet 29 is connected via a check valve 28 that opens. As a result, the water supplied from the water inlet 38 with the sealing cap is
When a predetermined amount of salt water is dissolved in the crude salt deposited on the
Opens to allow drainage. Conversely, the tap 29 in the normal state
Is not communicated with the flash chamber 30 due to the aforementioned pressure relationship.

The base of the flash chamber 30 is formed as an inclined tray 37a for condensed water and branches off on both sides, and one lower end is connected to the upper end of the suction port 36 by a sealable joint 36b. I have. The suction port is formed in an inverted funnel shape corresponding to the sealing lid 26, and its periphery is sealed by bolts 36a so that the peripheral portion 26 of the sealing lid 26 is closed.
a. The other branched lower end forms a fresh water outlet 37 connected to the tray 37a.

The bottom surface of the fresh water inflow section 45 above the fresh water tank 40 connected to the discharge port is closed when the pressure on the inlet side is lower than the outlet side, and is opened when a predetermined amount of load is applied on the inlet side. Such a check valve 46 is provided.

As shown in FIG. 3, the suction device 35 circulates water through a flowing water pipe 35a in a water tank by a motor pump having a required electric power of about 250 W.
By performing suction with the negative pressure generated in 5b, the pressure in the flash chamber 30 is reduced to a degree of vacuum of about 90 mmHg. A suction device (aspirator) itself for performing suction with circulating water instead of this kind of tap water is well known.

The heaters 19 and 25 of this device and the thermoelectric element 1
5. Motor pump of suction device 35 and pump 17 of cooling water
Has a total power consumption of about 650 W and is driven by a commercial power supply or a small generator.

The operation of the desalination apparatus thus constructed is as follows. Seawater 10a heated to about 70 ° C.
Foreign matter is removed by the filter 13 and supplied to the seawater heating chamber 20 lower than the seawater tank 10 through the cock 11.

The seawater 10 a heated to, for example, 75 ° C. in the seawater heating chamber 20 is pressed against the sealing lid 26 and
0 to the flash chamber 30 and the closed lid 2
Attempt to squirt onto the surface of 6. At this time, the felt 55 is infiltrated, and the pressure in the flash chamber 30 is reduced by the suction device 35.
The heated seawater infiltrated in the above is atomized and sprayed. Therefore, its surface is sufficiently exposed to vacuum and evaporates rapidly due to the low boiling point in vacuum and evaporator 35
To the upper end that connects to

This steam contacts the condenser 31 in the middle of the circulation of the cooling water, rapidly condenses, falls on the tray 37a as distilled water, and is supplied to the fresh water inlet 45 of the fresh water tank 40 along the slope. Then, the water is supplied from the check valve 46 to the fresh water tank 40 every time a predetermined amount is accumulated. The falling water droplets are reliably evaporated without containing un-evaporated seawater, and become fresh water containing almost no salt. On the other hand, the salt which has not evaporated is deposited on the surface of the closed lid 26 in a solid state.

It has been confirmed that the fresh water recovered in this way reaches 2 liters or more per hour.
It will be more than 48 liters in 4 hours. It is said that about 40 liters of tap water per day (excluding washing and bathing) used by a family of five is sufficient, and that household water such as cooking for three meals and drinking water can be supplied. Become. Seawater heating room 2
The seawater 10a, whose salinity has increased significantly at 0, is
Can be purified as crude salt by draining from
Available for food. If the felt 55 is clogged with salt during operation, the suction port 36 can be opened and replaced. Similarly, nozzle 50 can be removed if clogged with salt. The coarse salt deposited on the sealing lid 26 is poured from the water inlet 38 when not in operation, and the faucet 29 is opened to discharge as high-concentration salt water, which can be similarly purified as coarse salt.

In the above-described embodiment, the nozzle may be formed so as to protrude integrally with the sealing lid, and the cartridge may be detachably mounted. The infiltrated body may be formed by a fiber bundle, a sintered body, or the like exhibiting a capillary phenomenon. The seawater tank heater may be abolished and replaced with solar heat instead. Incidentally, it is conceivable to provide the suction device 35 in the cooling water tank 16 to circulate the cooling water. However, it is necessary to devise a point that the cooling effect is hindered by heat generated during the circulation.

[0021]

According to the first aspect of the present invention, a circulating water type aspirator is used as a vacuum device, and a thermoelectric element is used as a cooling device, so that a small and high power efficiency desalination device independent of a plant type. Can be realized. Seawater heated to a temperature lower than the boiling point on the premise of flash in terms of power efficiency is attached to the infiltration body and sucked into the flash chamber through the nozzle, so that seawater that has infiltrated at a higher speed than simple capillary action can be converted to high power. Evaporation is performed efficiently and without including unvaporized seawater, and high-purity freshwater is obtained. Therefore, it can be used in remote islands or ships by home electric power or small generators or in disaster-stricken areas where water supply is cut off due to disasters.

According to the second aspect of the present invention, since the infiltrated body can be replaced as a cartridge, maintenance at the time of clogging due to salt content becomes easy. According to the third aspect of the present invention, since the nozzle is also replaceable, manufacture of the nozzle is simplified, and maintenance at the time of clogging is facilitated.

According to the fourth aspect of the present invention, the seawater heating chamber has 7
By heating to about 0 ° C. to 90 ° C., the water is efficiently evaporated in combination with the suction action, and by communicating with the seawater tank through a pipe, the heat loss of the seawater heating chamber can be suppressed, and the salt concentration is relatively low. The raised seawater is drained so that crude salt can be purified.

According to the fifth aspect of the present invention, since the fresh water is recovered from the flash chamber via the check valve, it is possible to prevent the evaporation efficiency and the purity from being reduced due to the reduced degree of vacuum at the time of drainage. .

According to the sixth aspect of the present invention, the seawater in the seawater tank is heated by the heat radiation surface of the thermoelectric element, whereby the efficiency can be improved by preheating.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of a seawater desalination apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of a nozzle portion of the seawater desalination apparatus.

FIG. 3 is a diagram illustrating the principle of a suction device of the seawater desalination apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Seawater tank 15 Thermoelectric element 16 Cooling water tank 19, 25 Heater 20 Seawater heating chamber 30 Flash chamber 31 Condenser 35 Suction unit 40 Freshwater tank 50 Nozzle 55 Felt

Claims (6)

[Claims] 1. A seawater desalination apparatus for obtaining seawater by evaporating seawater and condensing the seawater with a condenser, wherein a seawater tank for storing seawater and seawater supplied from the seawater tank are heated to a temperature lower than a boiling point. A seawater heating chamber, a suction device that circulates a water flow through a pipe by a motor-driven pump, and suctions by a negative pressure generated at a branch port on the side surface of the pipe, and is supplied from the seawater heating chamber by being depressurized by the suction device. A flash chamber containing a condenser for evaporating seawater to be circulated and circulating a coolant, and a thermoelectric element for cooling the coolant by heat absorption by the Peltier effect, wherein the seawater heating chamber includes the flash chamber and And a nozzle which communicates with the flash chamber and has an infiltrating body attached to the tip thereof. Seawater desalination apparatus according to. 2. The seawater desalination apparatus according to claim 1, wherein the infiltration body is housed in a cartridge detachably attached to the nozzle. 3. The seawater desalination apparatus according to claim 1, wherein the nozzle is detachably screwed into the closing lid. 4. The seawater heating chamber communicates with a seawater tank through a pipe, and has a heater for heating seawater to about 70 ° C. to 90 ° C. and a discharge port for discharging seawater having a high salt concentration. The seawater desalination apparatus according to claim 1, wherein 5. The seawater desalination apparatus according to claim 1, further comprising a freshwater tank connected to the flash chamber via a check valve that opens when loaded with a predetermined amount of freshwater. 6. The seawater desalination apparatus according to claim 1, wherein seawater in the seawater tank is heated by a heat radiation surface of the thermoelectric element.