WO2001072638A1

WO2001072638A1 - Desalination device

Info

Publication number: WO2001072638A1
Application number: PCT/JP2001/002785
Authority: WO
Inventors: Yuzo Narasaki; Ichiro Kamiya; Naoyuki Inoue; Kiichi Irie; Toru Tokumaru; Tomoyuki Uchimura
Original assignee: Ebara Corporation
Priority date: 2000-03-31
Filing date: 2001-03-30
Publication date: 2001-10-04
Also published as: AU2001244681A1; JP4139597B2

Abstract

A device capable of an efficient desalination using a low-energy-density heat source such as solar energy. The desalination device comprises a solar heat collector (1), an evaporation system (2), a cooling tower (3), a distilled water tank (4), a concentrate brine tank (5), and a vacuum means (6), wherein the vacuum means (6) reduces pressures in evaporation spaces of respective evaporators in the evaporation system (2), steam generated in the preceding evaporator is introduced into the heat-exchanger of an applicable evaporator as a heat source, and generated steam and condensed water are supplied to the heat-exchanger of the next evaporator as a heating source, thereby enabling a multiple-effect use of a plurality of evaporators. A deaeration chamber is provided in the front-most stage of the evaporation system to deaerate a non-condensable gas from raw water supplied to evaporators. A pump (26) for feeding a condensed heat medium to the solar heat collector is provided in a heat medium circulating path. A condensed raw water used to generate steam in the evaporation system is fed into a condenser for use as a cooling water.

Description

Description Desalination equipment Technical field

The present invention relates to a desalination apparatus and method for obtaining fresh water (distilled water) from seawater, salt-containing groundwater (brine water), industrial wastewater, or the like using solar energy or another heat source. Background art

In recent years, the use of fresh water, such as domestic water, industrial water, and irrigation water, has increased, and conservation and effective use of water resources has become an increasingly important issue.

Devices for desalinating seawater have been known for some time, and large-scale desalination plants have been installed in the Middle East and elsewhere.

However, desalination equipment basically has the basic configuration of heating raw water such as seawater to form water vapor and condensing it to produce fresh water. In the past, it was common practice to consume large amounts of energy, such as fossil fuels and electricity.

On the other hand, in recent years, there has been a demand for a device that can reduce energy consumption as much as possible and that can efficiently desalinate, and its development has been carried out. For example, those that use solar heat and those that use waste heat from industrial bins have been developed and are being put to practical use, but further improvements are desired. ing.

The present invention has been made in view of such a point, and an object of the present invention is to provide a device capable of desalinating more efficiently. Disclosure of the invention

That is, the present invention provides a heat source, a plurality of evaporators, and an evaporator that generates steam from the raw water by heating the raw water with heat from the heat source. A condenser for receiving water vapor generated from heated raw water from the last evaporator of the evaporator and condensing it into distilled water, and depressurizing the space in the evaporator of the evaporator to below atmospheric pressure. A vacuum device, wherein the evaporator at the foremost stage receives raw water from the outside, and each evaporator is connected such that more than a predetermined amount of raw water flows down to the next evaporator. In addition, heat from the heat source is supplied to the heat exchanger of the first stage evaporator, and the steam generated from the raw water in the first stage heat exchanger is heated by the heat exchanger of the next stage evaporator. The condensed water generated by condensing the supplied water vapor by heat exchange with the raw water in the next-stage evaporator and the water vapor generated from the raw water by the heat exchange are further supplied to the next-stage evaporator. As a heat source to the heat exchanger And the same heating source is supplied to the following evaporator.The water vapor generated in the last evaporator is supplied to the condenser and condensed into distilled water. Provided is a desalination apparatus characterized in that it is taken out as desalinated water together with distilled water discharged from an evaporator. In this apparatus, since the steam and the condensed water generated in the evaporator in the preceding stage are used as a heating source in the heat exchanger in the next stage, the heat in the desalination apparatus can be effectively used.

Specifically, the vacuum device reduces the pressure in the evaporating space of each evaporator, the condensing space communicating with the evaporating space, and the distilled water storage space, and the concentration discharged from the last evaporator. Raw water can be used as cooling water for the condenser. In addition, the evaporator has a storage chamber for receiving raw water, and the raw water supplied to the foremost evaporator is passed through a raw water preheating pipeline that passes through at least some of the evaporator storage chambers. Later, it can be supplied to the first stage evaporator. Further, the evaporator has a deaeration chamber arranged in front of the foremost evaporator, and the deaeration chamber contains supplied raw water, and is heated by heat from a heat source to be contained in the raw water. The degasified raw water can be supplied to the foremost evaporator. By doing so, desalination can be performed more efficiently.

In addition, a condensed water passage for supplying the condensed water used as a heating source in one evaporator and condensed and generated by heat exchange to a next-stage evaporator as a heating source is provided. And a differential pressure can be generated before and after the throttle. By doing so, the non-condensable gas degassed from the raw water will The water can flow down without accumulating in the water, and it can be easily discharged to the outside.This also enables the heat exchange between the raw water and the heating source to be performed more appropriately, and thus enables efficient desalination. Will be able to do it.

Further, the present invention includes a heat source, a deaeration chamber for accommodating raw water, and a plurality of evaporators for accommodating raw water arranged in multiple stages following the deaeration chamber, and supplied from the heat source. An evaporator that heats and evaporates raw water by heat, in which raw water is introduced into a deaeration chamber, and the introduced raw water is sequentially sent to a subsequent evaporator, and is generated in each evaporator. Evaporator connected in a multiple-effect relationship so that the steam from the raw water is sent as a heating source for the subsequent evaporator, and receives and condenses the steam generated by the last evaporator in the evaporator A desalination system comprising: a condenser for producing fresh water; and a vacuum device for reducing the pressure of the deaeration chamber to below atmospheric pressure and discharging non-condensable gas generated by heating the raw water in the deaeration chamber. Provide equipment. The raw water supplied to the evaporator is degassed in the degassing chamber in advance to reduce the accumulation of non-condensable gas in the desalination unit, thereby improving the heat transfer between the raw water and the heating source. And increase the efficiency of desalination.

In this apparatus, a vacuum device is used to reduce the pressure in the condensation space of the condenser, the condensation space communicating with the evaporation space, and the evaporation space of the evaporator. It is preferable to perform the switching. This switching is because there is a large difference in the pressure inside the space to be reduced, and it is not efficient to reduce the pressure at the same time.

Further, it is preferable that the deaeration chamber and the steam inlet side of the condenser be connected to a vacuum device via a throttle. This is also to prevent stagnation of non-condensable gas as described above.

As a specific example, the evaporator is stacked up and down, the deaeration chamber is set on the top evaporator, and the deaeration chamber and the evaporator have storage tanks for storing raw water. The raw water stored in the tank overflows from the storage tank and flows down to the storage tank of the evaporator at the lower stage, and the raw water that overflows from the storage tank in the degassing chamber is U-shaped The U-shaped pipe section is provided with a saturated steam pressure at the highest temperature in the uppermost evaporator and the vacuum device. The head has a head corresponding to the differential pressure from the highest reduced pressure applied to the degassing chamber. Also, the heat source is a solar heat collector that heats the heat medium by solar energy, and the heat medium vapor from the solar heat collector is used as a heat source to exchange heat between the degassing chamber of the evaporator and the uppermost evaporator. The condensed heat medium supplied to the solar collector may be returned to the solar heat collector.

Further, the present invention provides a solar heat collector having a heat collecting panel that collects solar heat to heat a heat medium and generate steam of the heat medium, and a heat exchange for performing heat exchange between the heat medium and raw water. An evaporating device having a vessel, a raw water supply device for supplying raw water to the evaporating device, a condensing device for receiving and condensing water vapor generated in the evaporating device to form distilled water, A heat medium supply pipe for supplying the heat medium to the heat exchanger of the evaporator; and a heat medium for returning the heat medium condensed by heat exchange with raw water in the heat exchanger to the solar heat collector. A heat medium circulating circuit having a return line and circulating the heat medium in a thermosiphon system by repeating evaporation of the heat medium in a solar heat collector and condensation in a heat exchanger. Is provided in the heat medium return pipe and directs the condensed heat medium in the pipe to the solar heat collector. Having a heat medium circulation circuit having a pump for feeding Te provides a desalination apparatus according to claim. Since the heat medium can be supplied to the heat collecting panel by the pump, the level of the heat medium with respect to the heat collecting panel can be maintained at an appropriate level, and the heat collecting by the heat collecting panel to the heat medium can be performed properly. Can be. Specifically, in this apparatus, it is preferable to provide a buffer tank for containing the condensed heat medium in the heat medium return pipe upstream of the pump. Further, the pump has a capacity capable of supplying at least the amount of the heat medium which evaporates at the time of maximum solar radiation to the solar heat collector.

Still further, in the present invention, a heat source, an evaporator for heating raw water with heat supplied from the heat source to generate water vapor, and receiving and cooling and condensing water vapor generated by the evaporator to produce fresh water There is provided a desalination apparatus comprising: a condenser; and a cooling apparatus for introducing raw water, which is generated by generating steam in an evaporator and concentrated, into the condenser and uses it as cooling water. The cooling system is intended for more efficient desalination. In this device, the cooling device may have a blower fan, and the concentrated fan water may be cooled by the blower fan and used as cooling water for the condenser. it can. Furthermore, the evaporator has a heat exchanger, the heat source supply device is a solar heat collector that heats the heat medium by solar energy, and the heat exchanger receives the heated heat medium vapor and is connected to the raw water. Heat exchange can be performed. The evaporator includes a plurality of evaporators stacked in multiple stages, each evaporator having the heat exchanger, and these evaporators heat the steam from the raw water generated in each evaporator to the lower evaporator. The cooling device may be connected to a multiple-effect relationship adapted to be sent as a source, and the cooling device may introduce the concentrated raw water discharged from the lowermost evaporator into the condenser and use it as cooling water. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing a configuration example of a desalination apparatus according to one embodiment of the present invention.

FIG. 2 is a diagram showing a detailed configuration example of a part of a solar heat collector and an evaporator of the desalination apparatus.

FIG. 3 is a diagram showing a part of an evaporator of the desalination apparatus and a detailed configuration example of a concentrated water tank and a distilled water tank.

FIG. 4 is a diagram showing a detailed configuration example of a part of a vacuum means, a cooling tower, and an evaporator of the desalination apparatus.

FIG. 5 is a diagram showing a detailed configuration example of a distilled water tank, a concentrated water tank, and a cooling tower of the desalination apparatus.

FIG. 6 is a diagram illustrating a configuration example of a desalination apparatus according to another embodiment. Preferred embodiments of the invention

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a desalination apparatus using solar energy as a heat source will be described as an example. FIG. 1 is a diagram showing a configuration example of a desalination apparatus according to the present invention. This desalination device is composed of a solar heat collector 1, an evaporator 2, a cooling tower 3, a distilled water tank 4, a concentrated water tank 5, a vacuum means 6, and the like.

The solar heat collector 1 is composed of a plurality of solar heat collecting panels 11 to 11 to heat the heat medium by solar energy. The heat medium heated by the solar heat collector 1 passes through the pipe 7 The heat medium from the evaporator 2 is sent to the evaporator 2, and the heat medium from the evaporator 2 is stored in the buffer tank 9 through the pipe 8. It is designed to circulate back.

The evaporator 2 has a degassing chamber 2-1 at the top, and a plurality of evaporators (here, eight evaporators 2 to 2 to 8 to 9) are located below it. It is configured. The raw water (in this case, seawater) W is passed through the evaporator 2 (from the lower right in Fig. 1), and is passed through the evaporator 2 in order from bottom to top. Supplied to degassing chamber 2 — 1 The raw water supplied to the deaeration chamber 2-1 overflows when a predetermined amount is stored, and flows down to the first evaporator 2-2 through the overflow pipe 13 and similarly to the second to second evaporators. While flowing down while storing a predetermined amount in each evaporator of the 8th evaporator 2-9, it is heated and evaporated and gradually concentrated, and finally stored in the concentrated water tank 5 through the overflow pipe 14 It has become.

Part of the heated heat medium from the solar collector 1 is passed through the heat exchanger 2-1a located in the degassing chamber 2-1, and the other is located in the first evaporator 2-2 After passing through the heat exchanger 2-2a (see FIG. 2), heat exchange is performed between the deaeration chamber 2-1 and the raw water W stored in the first evaporator 2-2. Will be The water vapor evaporated by heating the raw water in the first evaporator 2-2 is sent as a heat source to the heat exchanger 2-3a in the second evaporator 2-3 through the steam pipe 15 and is sent to the raw water. The heat exchange takes place. Also, the steam evaporated by heating the raw water in the third evaporator 2-4 to the seventh evaporator 2-8 is sent to the heat exchanger of the next-stage evaporator as a heat source and exchanges heat with the raw water. Then, it is condensed and becomes distilled water, and is finally stored in the distilled water tank 4.

The concentrated raw water in the concentrated water tank 5 is sent to the lower tank 3-1a of the condenser 3-1 of the cooling tower 3 through the pipe 27 by the concentrated raw water discharge pump 16 and then the concentrated raw water circulation pump 17 It is supplied to the sprinkling nozzle 3-1 c and is sprayed as cooling water on a 3-lb condensation (heat transfer) pipe. The water vapor evaporated by the heating of the raw water in the eighth evaporator 2-9 in the final stage is sent through the pipe 18 to the condensing pipe 3-1b of the condenser 3-1 to be condensed with the concentrated raw water sprinkled. Heat is exchanged between the two and condensed to form distilled water, which is sent to the distilled water tank 4 through the pipe 19. The concentrated water overflowing the lower tank 3-1a is discharged through the concentrated water discharge line 20. The vacuum means 6 includes a gas-liquid separator 6-1 and a vacuum pump 5-2 connected to the gas-liquid separator 6-1. The gas-liquid separator 6-1 is connected to the pipe 7 through which the heat medium from the solar heat collector 1 passes through the pipes 21, 22, 23. The degassing chamber 2-1 of the evaporator 2, the condenser 3-1 The header is connected to 3-1 d. As a result, as described later in detail, the evaporation space of the evaporator 2 and the condensing space and the distilled water storage space communicating therewith can be reduced in pressure.

Further, the distilled water Wb in the distilled water tank 4 is discharged by a distilled water pump 25. In FIG. 1, V1 to V8 are pulp.

FIG. 2 is a view showing details of a part of the solar heat collector 1 and the evaporator 2 of the desalination apparatus. As shown in the figure, a plurality of solar thermal collector panels 1 of the solar thermal collector 1 — 1 to 1 The heat medium vapor Q 1 that has been heated and turned into steam is the heat exchanger 2— of the degassing chamber 2-1 1a and heat exchange between the deaeration chamber 2-1 and the raw water W stored in the first evaporator 221 through the heat exchanger 2-2a of the first evaporator 2-2. Then, it is condensed to be condensed as a heat medium Q 2 and stored in the buffer tank 9. The condensed heat medium Q 2 is sent to each solar heat collecting panel 11-1 to 1-6 of the solar heat collector 1 via the heat medium circulating pump 26.

FIG. 3 is a diagram showing details of a part of the evaporator 2, the concentrated water tank 5 and the distilled water tank 4 of the desalination apparatus. The raw water preheating line 12 is piped so as to pass through the raw water W stored in the eighth evaporator 2-9 to the second evaporator 23, and the raw water W passing through the raw water preheating line 12 is It is preheated by heat exchange with raw water (concentrated raw water) W in each evaporator. The raw water W preheated through the raw water preheating line 12 is supplied to the degassing chamber 2-1. The raw water W overflowing the degassing chamber 2-1 has a U-shaped outlet portion. The first evaporator 2-2 is supplied to the first evaporator 2-2 through the overflow pipe 13. The U-shaped portion 13a of the overflow pipe 13 has a saturated steam pressure corresponding to the highest temperature of the first evaporator 22 which is the uppermost evaporator, the maximum ultimate vacuum degree of the vacuum means 6, and It has a head corresponding to the differential pressure of The raw water W that has overflowed the first evaporator 2-2 is supplied to the second evaporator 2-3 through the overflow pipe 13, and similarly, the eighth stage evaporator 2 in the final stage — Flow down to 9 and each evaporator stores a certain amount of raw water.

The water vapor W a evaporated in the first evaporator 2-2 is the heat exchanger 2-3 in the second evaporator 2-3. a, heat exchange is performed between the raw water W and the raw water W, which condenses to become distilled water Wb, and the heat of the third evaporator 2-4 together with the steam Wa generated in the second evaporator 2-3. The heat is sent to exchanger 2-4a and exchanges with the raw water. Then, it condenses and becomes distilled water Wb and is sent to the heat exchanger 2-5a of the fourth evaporator 2-5 together with the water vapor Wa generated in the third evaporator 2-4. As described above, evaporation and condensation are repeated in each evaporator in order, and the distilled water Wb condensed in the heat exchanger 2-9a of the eighth evaporator 2-9 in the final stage is supplied to the distilled water tank 4. You.

FIG. 4 is a diagram showing details of a part of the vacuum means 6, the cooling tower 3 and the evaporator 2 of the desalination apparatus. As shown in the figure, the deaeration chamber 2-1, the pipe 7 through which the heat medium passes, and the condenser 3-1 of the cooling tower 3 are connected to the vacuum pump 6-2 through the pipes 21, 22, 23. As a result, the internal space of the deaeration chamber 2-1, the pipe 7 and the internal space of the first evaporator 2-2 communicating therewith, the header 1-3-1d of the cooling tower 3, and the condensing pipe 3-1b The condensing space can be decompressed. In addition, the evaporation space and the condensation space of each evaporator after the second evaporator 2-3 are communicated with the steam pipe 15 so that the pressure can be similarly reduced. In addition, exhaust is performed through an exhaust pipe 6-3 connected to a discharge port of the vacuum pump 6-2.

FIG. 5 is a diagram showing details of the distilled water tank 4, the concentrated water tank 5, and the cooling tower 3 of the desalination apparatus. The steam W a evaporated in the eighth evaporator 2-9 of the evaporator 2 is sent to the condenser 3-1 through the pipe 18 and from the watering nozzle 3-1c while passing through the condensation pipe 3-1b. Cooling is performed by heat exchange between the concentrated raw water W to be sprayed and the air sent from the fan 3-2, and the condensed water W b is sent to the distilled water tank 4. At this time, the concentrated raw water W sprayed from the watering nozzle 3-1 c is cooled by the air sent from the fan 2-2, so that the water vapor Wa is efficiently condensed.

A raw water tank (not shown) that can always supply raw water at atmospheric pressure or higher will be installed in the desalination apparatus with the above configuration. In the initial stage of installation of the desalination unit, a system that requires a vacuum state during operation of the evaporator 2 etc. 3-1 Condensing space, distilled water tank 4 and concentrated water tank

(Distilled water and concentrated water storage space of 5). Then, by opening the valve V8, a specified amount of raw water is introduced using vacuum pressure. After the desalination unit starts operation, Since the pressure is constantly reduced, the valve V8 is automatically opened and closed so as to maintain the level of the raw water W of the first evaporator 2-2 according to the amount of evaporation. It can be supplied in the room. The raw water W may be supplied using a raw water supply pump 11.

Solar heat collector 1 absorbs solar energy and heats the internal heating medium. The heat medium heated in the solar heat collector 1 whose inside is depressurized evaporates to become heat medium vapor Q1, and the heat exchanger 2-1a of the deaeration chamber 2-1 and the first evaporator 2 The heat is exchanged with the raw water W that is introduced into the heat exchangers 2-2 a and is stored therein.The raw water W is heated, and the heat medium vapor Q 1 is condensed and condensed heat medium Q2. As described above, the heat medium is naturally circulated by repeating evaporation and condensation, that is, circulated by a thermosiphon. In this case, the heat circulating pump 8 further condenses the condensed heat medium Q 2 to the heat collecting panel 1 of the solar heat collector. It is designed to be able to forcibly supply power to 11 to 11 n so that the level of the heat medium in the solar collector can be kept constant.

The raw water W of the first evaporator 2-2 evaporates and generates water vapor Wa when heated by the heat medium vapor Q1. This water vapor Wa is supplied to the heat exchanger 2-3a of the second evaporator 2-3, and heat exchange is performed with the raw water W stored in the second evaporator 2-3. At the same time as the raw water W is heated, the heat is deprived and condensed to become distilled water Wb. The water vapor Wa generated by the heating of the raw water W is transferred to the heat exchanger 2-4a of the third evaporator 2-4, and is separated from the raw water W stored in the third evaporator 2-4. Heat is exchanged in the raw water, and at the same time heat is taken away and condensed to form distilled water Wb. The same process is repeated in this way.

The water vapor W a evaporated in the seventh evaporator 2-8 preceding the eighth evaporator 2-9 is transferred to the heat exchanger 2-9a of the eighth evaporator 2-9, where heat is transferred to the raw water W. Exchange is done, raw water

At the same time as W is heated, it is deprived of heat and condensed to become distilled water, which is transferred to the distilled water tank 4. Further, the water vapor W a evaporated in the final stage of the eighth evaporator 2-9 is transferred to the condenser 3-1 in the cooling tower 3, where the concentrated raw water W sprayed from the water spray nozzle 3-1c and The air sent from fan 3-2 removes heat and condenses into distilled water. Then, it is transferred to the distilled water tank 4.

The raw water W supplied to the evaporator 2 is the raw water in the eighth evaporator 2-9 to the second evaporator 2-3. It passes through the raw water preheating line 12 that passes through the water W. The raw water W stored in the eighth evaporator 2-9 to the second evaporator 2-3 holds heat, and heat exchange is performed with the raw water W passing through the raw water preheating pipeline 12. The raw water W passing through the raw water preheating line 12 is preheated. As a result, the heat of the concentrated raw water W in the eighth evaporator 2-9 to the second evaporator 2-3 is effectively used.

Further, the non-condensable gas contained in the raw water W is degassed in the deaeration chamber 2-1 before being supplied to each of the first evaporator 2-2 to the eighth evaporator 2-9. . If the non-condensable gas is not degassed, the non-condensable gas also enters the steam when the raw water is heated and evaporated in the evaporator, and the steam and the raw water Wa in the heat exchanger in each evaporator are mixed. In this respect, the degassing of the non-condensable gas will improve the distillation performance, since the heat transfer between them will be hindered.

The water vapor Wa generated in each evaporator of the first evaporator 2-2 to the seventh evaporator 2-8 is heated and condensed into the distilled water by heating the raw water W of the latter evaporator. Along with the steam W a generated by heating the raw water W in the above, it is further introduced into the heat exchanger of the subsequent evaporator. In other words, each evaporator of the first evaporator 2-2 to the seventh evaporator 2-8 is provided with a steam pipe 15 and a distilled water flow path 28 with a throttle through which distilled water Wb generated by condensing steam passes. Are communicated with each other. Thereby, not only the latent heat of condensation of the steam W a but also the sensible heat of the distilled water W b can be effectively used. Also, by providing the distilled water flow path 28 with a restrictor (orifice), the distilled water flow path 28 communicates with the steam condensing space of the upstream evaporator and the steam condensing space of the downstream evaporator. A pressure difference is generated, so that the non-condensable gas flows down to the downstream evaporator together with the condensed water without staying in the upstream condenser. The accumulation of the non-condensable gas in the evaporator impedes the heat transfer between the steam and the raw water Wa in the heat exchanger in each evaporator, but can prevent this.

In each evaporator of the first evaporator 2-2 to the eighth evaporator 2-9, an overflow pipe 13 is arranged in each evaporator so that the supplied raw water W always maintains a specified amount. The concentrated raw water W that has overflowed through the overflow pipe 13 is introduced as raw water W into a downstream evaporator. In other words, each evaporator is supplied with concentrated raw water in sequence from the previous evaporator. This makes it possible to increase the temperature The raw water becomes the heat source of the raw water for the next stage evaporator, and the efficiency becomes higher. Since the evaporators at each stage are in communication with each other, raw water w can be continuously supplied, and distilled water Wb and concentrated raw water W can be continuously discharged. Therefore, the amount of raw water W retained in the evaporators of each stage from the first evaporator 2-2 to the eighth evaporator 2-9 can be reduced, so that the desalination apparatus becomes compact and the amount of heat of the retained raw water W is also small. I just need to. As a result, a large amount of distilled water Wb can be obtained with a small heat supply amount, and efficient operation can be performed. And since the amount of raw water w is small, quick response and efficient operation due to solar radiation fluctuations are possible.

The distilled water evaporated and condensed in the evaporators at each stage of the first evaporator 2-2 to the eighth evaporator 2-9 is collected in the distilled water tank 4. Then, when the amount of distilled water in the distilled water tank 4 reaches a specified amount, or continuously, the distilled water is discharged and recovered outside the system at atmospheric pressure by the distilled water pump 25.

The concentrated raw water W that has passed through the first evaporator 2-2 to the eighth evaporator 2-9 without being evaporated in each stage evaporator reaches the concentrated water tank 5. Then, when the amount of concentrated raw water in the concentrated water tank 5 reaches a specified amount or continuously, the concentrated raw water discharge pump 16 is transferred to the lower tank 3-1 a of the condenser 3-1 of the cooling tower 3 by the concentrated raw water discharge pump 16. The concentrated raw water of 3-1a is supplied as cooling water to the sprinkling nozzle 3-1c by the concentrated raw water circulating pump 17 and sprinkled on the condensing pipe 3-1b.

The supply amount of the raw water W to the first evaporator 2-2 is adjusted to prevent evacuation in each evaporator, improve maintainability, and improve durability. The heat exchangers 2-2 a to 2-9 a in the evaporator 9 do not always dry up from the raw water, and are transferred and discharged from the concentrated water tank 5 through each evaporator. The concentration ratio of the concentrated raw water W is set to be less than the scale deposition ratio (for example, 1.5 for seawater).

By installing the cooling tower 3 and keeping the temperature of the concentrated raw water W at the final stage constant around the outside air temperature, for example, a rise in the cooling water temperature of the cooling tank (fresh water This can prevent a drop in distillation performance in the afternoon due to an increase in the amount of heat possessed by the entire liquefier, and secure a high yield of distilled water. In addition, since the water vapor Wa evaporated in the final stage of the eighth evaporator 2-9 can be continuously cooled, continuous evaporation and condensation are performed. If it is possible to secure a heat source other than the solar heat collector 1, it can be operated continuously for 24 hours.

In this way, the amount of raw water W and the amount of heat retained are small, and the cooling tower 3 is installed to maintain the temperature of the final stage condensed water W at almost the outside air temperature (for example, the outside air temperature of 30 ° C). That is, by preventing the temperature of the condensed water from rising, and by performing continuous operation, for example, the heat collection temperature collected by the normal solar heat collection panels 11 to 16 (for example, the heat medium vapor inlet temperature 65 °) C) and the raw water inlet temperature (for example, the raw water inlet temperature of 32 ° C.), in this embodiment, the evaporator 2 was used as the double evaporator for the first evaporator 2-2 to the eighth evaporator 2-9. This makes it possible to effectively use solar energy with a low energy density eight times repeatedly.

In the batch type desalination apparatus, every time the raw water is replaced, it is necessary to evacuate the apparatus from the atmospheric pressure, which requires an extremely large power consumption. However, in the desalination apparatus according to the present invention described above, After evacuation from the atmospheric pressure in step (2) to reduce the pressure in the entire system, the operation is performed by continuously supplying raw water, and only the noncondensable gas generated as a result is required. Since there is no need to evacuate from atmospheric pressure, significant energy savings can be achieved.

When the sun goes down and there is no solar radiation, evaporation stops and the supply of raw water stops. That is, the desalination operation stops. Then, the next day, when the sun rises and evaporation in the evaporator 2 starts, raw water W is newly supplied by the amount of evaporation and the desalination cycle starts to rotate. For this reason, desalination operation is possible by driving a pump etc. only when heat is supplied. In other words, when solar heat is being supplied from the solar heat collector 1 to the evaporator 2 due to the solar radiation, the solar power generation system that can supply the necessary power can be generated at the same time. It becomes a desalination unit.

If continuous operation is possible, the pump or the like may be driven only when the heat source is supplied from the solar heat collector 1 to the evaporator 2. In other words, if a solar power generation facility is installed, power can be generated at the same time when the sun is shining and a heat source is being supplied, and the necessary power can be supplied.

In addition, pumps and other electric equipment can be operated intermittently or staggered to reduce the required capacity of the solar power generation system during peak hours. Since the capacity of the solar power generation system, which converts DC power into AC power, can be reduced, a compact solar power generation system can be constructed. If the system and operation flow can be optimized, power storage equipment will not be required, and a more compact, safe and maintenance-free power supply system can be constructed. Since vacuum pumps require a certain degree of high vacuum (for example, a saturated vapor pressure of 31.8 mmHg at an ambient temperature of 30 ° C) to repeatedly use solar energy with a low energy density, In the desalination equipment, an oil rotary type vacuum pump was used as a vacuum means.However, water vapor was sucked during operation, so water was mixed into the oil. Has been troubled by Here, oil-water separation tanks were installed, and the equipment required for oil-water separation was shut down (for example, once a day for 8 hours at night, etc.) to separate water from oil. This enabled daily operation. Furthermore, using a scroll-type vacuum pump that does not use oil eliminates the need for oil maintenance and enables continuous operation for 24 hours. The first evaporator 2-2 to the eighth evaporator 2-9 that constitute the evaporator 2 have a sufficiently wide evaporation area by using horizontal evaporators with long heat transfer tubes installed in the horizontal direction. As a result, the steam velocity can be suppressed, so that the amount of mist (ie, small droplets of raw water containing salt) accompanying the water vapor Wa can be reduced. In addition, the height from the evaporation surface of the water vapor in the evaporator to the vapor outlet of the evaporator must be sufficient, and the mist accompanying the vapor along with the vapor in the flow path from the evaporator to the vapor outlet must be collected. By providing a baffle plate, high-quality distilled water could be obtained (5 ^ S / cm in this example).

If the evaporator has multiple effects, such as the first evaporator 2-2 to the eighth evaporator 2-9, the evaporator can be made compact by using a vertical integrated structure, and the steam Wa, distilled water By making Wb and concentrated raw water W flow naturally, unnecessary power is not required. In addition, the on-site transportation work is only the installation of the main body and the assembling of the gantry and panels, making the work easier.

FIG. 6 is a diagram showing another configuration example of the desalination apparatus according to the present invention. This desalination unit differs from the desalination unit shown in Fig. 1 in that steam is condensed from the deaeration chamber 2-1 and the condenser 3-1 on the steam inlet side, that is, from the eighth evaporator 2-9. Pipes 1 and 8 The point is that they communicate with each other via a diaphragm 30 such as a orifice. This is because, by providing a pressure difference before and after the throttle 30, the uncondensed gas degassed in the degassing chamber 2-1 does not stay in the degassing chamber, but flows down in the pipe 29 to form the condenser 3- This is to make it easier to flow out through the pipe 1, the pipe 23, the valve V3, and the vacuum means 6.

In the above-described embodiment, an example in which the solar heat collector 1 is used as the heat source is described.However, the heat source is not limited to this, and any heat source that can directly or indirectly supply an external heat source to the evaporator 2 is used. I just need.

In the desalination apparatus according to the above-described embodiment, the following effects can be obtained.

(1) Reduce the pressure in the evaporation space of each evaporator of the evaporator and the condensing space and the distilled water storage space communicating with the evaporation space by vacuum means, and use the steam generated in the evaporator in the preceding stage to heat exchanger the evaporator. As a heat source, the generated steam and condensed distilled water are supplied to the heat exchanger of the next evaporator as a heat source, and multiple evaporators are used for multiple effects. Fresh water can be obtained from raw water efficiently using a heat source with energy density.

(2) Since the evaporators are connected to each other so that the steam, distilled water and raw water exceeding a predetermined amount generated in each evaporator are supplied to the next evaporator, the raw water is continuously supplied. Can be supplied, and continuous operation of continuously discharging distilled water and concentrated raw water becomes possible. In addition, since the amount of raw water held by each stage evaporator is small and the equipment is compact, and the amount of heat retained is small, efficient desalination operation that can obtain a large amount of distilled water with a small amount of supplied heat is required. It becomes possible. In addition, since continuous operation is possible, the evacuation space of the evaporator, which requires the most power in the desalination unit, the condensing space connected to it, and the evacuation from the atmospheric pressure of the distilled water storage space, etc. Becomes unnecessary.

(3) In addition, since the steam generated in the last-stage evaporator is supplied to the condenser of the cooling tower and the concentrated raw water in the concentrated water tank is used as the cooling water in the condenser, the temperature of the concentrated water in the final stage is reduced to outside air. The temperature can be kept close to the temperature. For example, it is possible to prevent a decrease in the distillation performance in the afternoon due to a rise in the cooling water temperature of the cooling tank (increase in the amount of heat held by the entire apparatus), which is a problem in batch type desalination equipment with a cooling tank. it can. In addition, since the water vapor evaporated in the last stage evaporator can be continuously condensed in the condenser, continuous evaporation and condensation are possible. If the heat source can be secured, desalination operation can be performed continuously for 24 hours.

(4) In addition, the steam and condensed water generated in the previous evaporator are introduced into the heat exchanger of the evaporator as a heat source, and the generated steam and condensed distilled water are used as heat sources in the heat exchanger of the next evaporator. The sensible heat of distilled water as well as the latent heat of condensation of water vapor Wa can be used effectively.

(5) In addition, since each evaporator supplies more than a predetermined amount of raw water to the next-stage evaporator, the raw water with a high temperature level in the previous-stage evaporator becomes the heat source of the raw water for the next-stage evaporator. , More efficient.

(6) Since a cooling tower cooperating with the condenser is provided, the concentrated raw water supplied as cooling water to the condenser can be forcibly cooled by air sent from a fan provided in the cooling tower. The condensing efficiency of the vessel is high and can be maintained stably, enabling highly efficient desalination operation.

(7) By using a cooling tower, the condensing temperature can be kept low, and the heat collecting temperature of the solar heat collector decreases, so it is possible to increase the heat collecting efficiency and increase the amount of heat collected, and increase the freshwater yield. Can be expected.

(8) The raw water supplied to the evaporator of the evaporator is preheated through the raw water preheating pipe with the heat retained in the raw water of at least a part of the evaporator (raw water already supplied to the evaporator and heated). The heat in the evaporator can be used effectively.

(9) Since the evaporator has a deaeration chamber in front of the foremost evaporator, it can remove non-condensable gas that hinders heat transfer, improve distillation performance, and improve fresh water. Can be performed continuously instead of batchwise.

(10) By communicating the deaeration chamber with the steam inlet side of the condenser via a throttle, the non-condensable gas generated in the deaeration chamber is removed from the condensation space of the condenser via a vacuum means. Degassing and discharging becomes easy. In addition, by providing a restrictor also in the condensed water passage between the evaporators, discharge of non-condensable gas is facilitated, and obstruction of heat exchange due to the gas remaining in the evaporator is prevented. be able to.

(11) By providing a heat medium circulating means for circulating the condensed heat medium in the condensed heat medium flow path in the heat medium circulation circuit, the heat collecting panel of the heat Even during the initial evaporation at sunrise, there are also problems such as liquid pools in the entire solar collector. Even if the liquid level of the heat medium fluctuates, the heat transfer surface of the heat collecting panel can be filled with the heat medium, the total amount of solar radiation can be used effectively, and intermittent solar radiation (variation of solar radiation) Therefore, an excellent effect that the followability up to the evaporation of the heat soot can be improved. Applicability of the invention

The desalination apparatus according to the present invention is different from a conventional apparatus using a fossil fuel or electric power as a heat source, unlike a device that can be used only in a limited place where the heat source equipment can be obtained. It can be installed anywhere, and can efficiently use low-density energy such as solar energy to desalinate water.

Claims

The scope of the claims

1. Heat source,

An evaporator that includes a plurality of evaporators and generates steam from the raw water by heating the raw water with heat from the heat source;

A condenser for receiving water vapor generated from the raw water heated in the evaporator from the last evaporator of the evaporator and condensing it into distilled water;

A vacuum device for reducing the pressure in the evaporator of the evaporator to below atmospheric pressure,

The evaporator is arranged such that the foremost evaporator receives raw water from the outside, and each evaporator is connected so that more than a predetermined amount of raw water flows down to the next evaporator. Heat from the heat source is supplied to the heat exchanger of the foremost evaporator, and steam generated from raw water in the foremost heat exchanger is supplied as a heating source to the heat exchanger of the next evaporator. The condensed water generated by the supplied steam being condensed by heat exchange with the raw water in the next-stage evaporator, and the steam generated from the raw water by the heat exchange are further converted into the heat of the next-stage evaporator. The heat source is supplied to the heat exchanger, and the same heat source is supplied to the following evaporators. The steam generated in the last evaporator is supplied to the condenser to be condensed and distilled water is supplied. From the last evaporator A desalination plant characterized by being extracted as desalinated water along with the distilled water discharged.

2. The desalination apparatus according to claim 1,

A desalination apparatus, wherein the vacuum device is configured to decompress an evaporation space of each evaporator, a condensation space communicating with the evaporation space, and a distilled water storage space.

3. The desalination apparatus according to claim 1 or 2,

A desalination apparatus, wherein concentrated raw water discharged from the last-stage evaporator is used as cooling water for the condenser.

4. The desalination apparatus according to claim 1, 2 or 3,

The heat source is a solar heat collector that heats a heat medium by solar energy, and supplies the heat medium vapor of the solar heat collector to the heat exchanger of the foremost evaporator as a heat source. A desalination apparatus characterized in that:

5. The desalination apparatus according to claim 1, 2, 3, or 4,

The evaporator has a storage chamber for receiving raw water, and the raw water supplied to the foremost evaporator is passed through a raw water preheating conduit passing through at least a part of the evaporator storage chamber. A desalination apparatus characterized in that the desalination apparatus is supplied to the foremost evaporator.

6. The desalination apparatus according to any one of claims 1 to 5,

The evaporating apparatus has a deaeration chamber disposed in front of a foremost evaporator, and the deaeration chamber contains supplied raw water, and is heated by heat from the heat source to be contained in the raw water. A desalination apparatus, wherein degassed gas is supplied and the degassed raw water is supplied to the foremost evaporator.

7. The desalination apparatus according to any one of claims 1 to 6, wherein

A condensed water passage for supplying the condensed water, which is used as a heating source in one evaporator and is condensed by heat exchange, to a next-stage evaporator as a heating source, and a throttle is provided in the passage; A desalination apparatus wherein a differential pressure is generated before and after the restriction.

8. Heat source,

An evacuation chamber for accommodating raw water; and a plurality of evaporators for accommodating raw water arranged in multiple stages following the deaeration chamber, wherein the evaporator heats and evaporates the raw water by heat supplied from the heat source. Raw water is introduced into the deaeration chamber, and the introduced raw water is sequentially sent to the subsequent evaporator, and the water vapor generated from the raw water generated in each evaporator is converted into the downstream evaporator. An evaporator connected in a multi-effect relationship adapted to be sent as a heating source for the

A condenser for receiving and condensing steam generated in the last-stage evaporator in the evaporator to produce fresh water;

A vacuum device for reducing the pressure of the degassing chamber to an atmospheric pressure or less, and discharging an uncondensed gas generated by heating the raw water in the degassing chamber;

A desalination apparatus comprising:

9. The desalination apparatus according to claim 8, The vacuum device is configured to decompress the condensing space of the condenser, the condensing space communicating with the evaporating space, and the evaporating space of the evaporator. A desalination apparatus characterized in that the process is performed by switching.

10. The desalination apparatus according to claim 8 or 9,

A desalination apparatus, wherein the desalination apparatus is connected to the vacuum device via the deaeration chamber and a steam inlet side of the condenser.

11. The desalination apparatus according to claim 8, 9 or 10,

The evaporator is stacked on top and bottom,

The degassing chamber is set on the uppermost evaporator,

The degassing chamber and the evaporator have a storage tank for storing raw water,

The raw water stored in each storage tank overflows from the storage tank and flows down to the storage tank of the evaporator below.

Raw water that overflows from the storage tank of the degassing chamber flows down to the storage tank of the uppermost evaporator through a pipe having a U-shaped pipe part.

The U-tube portion has a head corresponding to a pressure difference between a saturated vapor pressure at the highest temperature in the uppermost evaporator and a maximum reduced pressure applied to the deaeration chamber by the vacuum device. A desalination apparatus characterized in that:

1 2. The desalination apparatus according to claim 11,

The heat source is a solar heat collector that heats a heat medium by solar energy. The heat medium vapor from the solar heat collector is used as a heat source, and the deaeration chamber of the evaporator and the uppermost evaporator are used. A desalination apparatus, wherein the condensed condensed heat medium is supplied to the heat exchanger and returned to the solar heat collector.

1 3. A solar heat collector having a heat collecting panel that collects solar heat to heat the heat medium and generate steam of the heat medium;

An evaporator having a heat exchanger for performing heat exchange between the heat medium and the raw water, a raw water supply device for supplying raw water to the evaporator,

A condensing device for receiving and condensing water vapor generated in the evaporator into distilled water;

Heat medium for supplying the heat medium turned into steam by the solar heat collector to the heat exchanger of the evaporator A supply pipe, and a heat medium return pipe for returning the heat medium condensed by heat exchange with raw water in the heat exchanger to the solar heat collector, and A heat medium circulating circuit for circulating the heat medium in a thermosiphon system by repeating evaporation and condensation in the heat exchanger, wherein the heat medium circulation circuit is provided in the heat medium return pipe, and is provided in the heat medium return pipe. A heat medium circulating circuit having a pump for feeding a heat medium toward the solar heat collector;

A desalination apparatus comprising:

14. The desalination apparatus according to claim 13,

A desalination apparatus, further comprising: a buffer tank that stores a condensed heat medium in the heat medium return pipe upstream of the pump.

15. The desalination apparatus according to claim 13 or 14,

The desalination apparatus, wherein the pump has a capacity capable of supplying at least an amount of a heat medium that evaporates at the time of maximum solar radiation to the solar heat collector.

1 6. Heat source,

An evaporator that heats raw water with heat supplied from the heat source to generate steam, a condenser that receives the steam generated by the evaporator, cools and condenses it, and generates fresh water;

A cooling device for introducing raw water concentrated by generating water vapor in the evaporator to the condenser and using it as cooling water;

A desalination apparatus comprising:

17. The desalination apparatus according to claim 16,

The cooling device has a blower fan, and the concentrated raw water is cooled by the blower fan and used as cooling water for the condenser.

18. The desalination apparatus according to claim 16 or 17,

The evaporator has a heat exchanger,

The heat source supply device is a solar heat collector that heats a heat medium by solar energy, and the heat exchanger receives the heated heat medium vapor and exchanges heat with raw water. Desalination equipment.

19. The desalination apparatus according to claim 16, 17, 17, or 18, wherein the evaporator includes a plurality of evaporators stacked in multiple stages,

Each evaporator has the heat exchanger,

These evaporators are connected in a multiple-effect relationship in which steam from raw water generated in each evaporator is sent to a lower evaporator as a heating source,

The desalination apparatus, wherein the cooling device introduces concentrated raw water discharged from a lowermost evaporator into the condenser and uses it as cooling water.