KR800000699B1 - Process for the purification of water - Google Patents

Abstract

A process for purification of water by solar energy is described. The process comprises several steps of the spreading of water onto a solar-heat absorbing surface so as to from a sheet of water, the feeding of a liq. which is having a vapor pressure and density less than water and transparent to the radiation, the heating of water by direct-and reflected solar radiation, the feeding of heated water from the surface to an evaporator, and the evaporating of a portion of water.

Description

Purification of water by distillation

1 is a cross-sectional view of a first aspect of the apparatus structure of the present invention.

2 is a cross-sectional view of a second aspect of the apparatus structure of the present invention.

3 is a partial cutaway perspective view of the first aspect of the fan structure

4 is a partial cutaway perspective view of a second aspect of the fan structure

An object of the present invention is to provide a method for purifying water by distillation using solar energy directly.

Desalination of seawater has been carried out for a long time by the apparatus using solar energy. Nevertheless, various known distillation apparatuses using solar energy have not been generally used because of the high production cost of water by this type of apparatus because of the high relative cost of capital investment and processing thereof.

All devices that have been used up to now employ a physics phenomenon known as the “conservatory effect”. When this happens, the water warms up and is caused by the action of the sun's rays through a transparent cover of plastic or glass material. Water evaporates. Since there is a temperature difference between the inside and outside of this greenhouse, part of the water vapor is concentrated on the carver to capture the desalted water.

Experience has shown that the device of the type described above is inherently expensive and its assembly cost is directly proportional to the surface area, which is naturally proportional to the amount of water obtained. Some of these devices have a structure with a pan completely covered with a transparent roof, which operates as a thickening unit, a unit for sealing the pan and a reservoir for proper removal. The transparent roof structure and fixed roof of the roof on the fan are two of the costly features of this device, and the components of these devices are corrosion resistant and chemically inert to sunlight in order to ensure mechanical stability that can withstand strong winds. If this is required, it is necessary to satisfy the condition.

It is an object of the present invention to drastically reduce the cost of operation in various known methods and to obtain a drink from contaminated water or a method of purifying water by distillation, in particular of desalination of sea water.

Therefore, the method of the present invention maintains the water to be treated on the surface having the property of absorbing sunlight by accumulating solar energy in a sheet form, and the te-ray beam is permeable to the sheet-like water and cannot be mixed with water. Covered with a layer of liquid material having a vapor pressure lower than water, irradiated with sunlight to obtain what is thus obtained, removing a small amount of the heated water, evaporating a portion of the removed water and concentrating at least a portion of the formed water vapor and recovering it into the liquid phase. It is characterized by.

The component which ensures heating by solar energy is separated from the component which performs distillation operation as mentioned above. By this separation, it becomes possible to make the fan for heating by sunlight in a very economical form, and moreover, the fan is not only low in cost of maintenance but also sensitive to weather factors such as wind, sand and dust. It is not in the form. By separating solar heating and distillation, it is possible to condense water vapor using a coolant other than atmospheric air, so that the surface area of each concentration unit can be significantly reduced and the quantity can be greatly increased. In addition to this, the overall manufacturing cost of the processing unit having a constant production capacity can be lowered.

It is an object of the present invention to conduct heat treatment of water by solar energy in a zone having a large surface area while avoiding unnecessary simultaneous cooling by evaporation, in which subsequent evaporation of the heated water is carried out in a zone distinct from the first zone, This is achieved by easily obtaining the collection of distillate.

Examples of liquid materials which have solar permeability and are not miscible with water and have a vapor pressure lower than that of water include translucent or translucent oils at the heating temperature of the water on the sheet, for example mineral oils, vegetable oils or animal oils having a high molecular weight and moderate melting point. This is preferably used. This oil is preferably colorless, but may be slightly colored. This material is less dense than water, is not photochemically affected by sunlight, is stable against air and is chemically stable in contact with water, for example seawater.

It is advantageous for this liquid substance to have a high firmness, a melting point of at least 0 ° C. and a refractive index similar to that of water (about 1.33).

In addition, it is advantageous that this material does not transmit infrared heat rays, i.e., electromagnetic radiation having an exaggeration of 5 microns or more, so that all the heat loss of the water layer due to infrared ray radiation can be avoided.

For example, paraffinic oil (product of shell company known as Nassa oil 79) having density 0.904 and viscosity 33 ° E (degrees engler) at 20 ° C as a sun-transparent liquid substance, density 0.905 and viscosity 75 ° E at 20 ° C. A paraffinic oil having a density of 0.892 at 20 ° C. and a paraffinic oil having a viscosity of 15 ° E at 20 ° C., or a paraffin oil having a density of 0.88 at 20 ° C. Can be used.

These liquid substances can be used as mixtures of agents which inhibit the reaction of these oils with antioxidants and / or salts dissolved in water, antifoaming agents and substances which lower the solidification temperature of the oil.

The thickness of the liquid layer which cannot be mixed with water is preferably between 0.1 and 3 cm.

It is preferable that the thickness of the sheet-like water is about 20 cm at maximum, and it can raise temperature of water continuously by this. The optimum value of this thickness depends on the separation conditions and the desired operating arrangement. In practice, this value is between 1 and 10 cm, in particular between 2 and 6 cm. For the thickness of the rule on the sheet of 20 cm or less, it is important to note that the temperature of the water on the sheet is time-dependent during the day, and the fluctuation depends on the season and climatic conditions.

The thickness of the sheet-like water can be made 20 cm or more when the fluctuation range of the temperature is not less than that of rapidly heating and heating the sheet-like water. In solar energy accumulation, as a surface having the property of absorbing sunlight, it is preferable to use a shallow depth bottom fan having a bottom at least dark color. By absorbing the light rays by this surface, at least most of the water can be heated at the bottom of the sheet during its light irradiation. In order to enhance the heating effect of water, particles or pigments of a dark inert substance such as carbon having a property of accumulating thermal energy to absorb sunlight and then transferring it to water may be dispersed in water.

To promote heat exchange by convection between the layer of water and immiscible material covering the surface of the sheet and the atmosphere, at least one screen is used to transfer at least a portion of the thermal energy of sunlight over at least a portion of the layer of material. It can be installed to isolate the air layer between this screen and this material layer. Furthermore, a plurality of hollow bodies, for example spherical bodies, made of a material such as glass that transmits at least a part of sunlight can be placed on a part of the sheet surface.

In order to reduce the risk of peeling off of the surface layer of liquid substance which cannot be mixed with the water covering the sheet-like water, this layer is immersed in the sheet by immersing a network of wall members. Can be separated. The wall means of the network preferably covers at least part of it with a material which transmits at least part of the sunlight. Alternatively, this separation can be accomplished by placing frame members on water. In order to increase the intensity of the light received by the sheet under certain conditions, it is possible to use at least one reflector, for example a reflecting surface having one flat or concave surface or a plurality of reflecting surfaces arranged so that the light beams are reflected on the sheet surface. have.

It is advantageous to use at least one adjustable reflecting layer, preferably having a reflecting surface half facing south, so that the reflecting angle of the light beam can be adjusted in the best way according to the angle of incidence of the sunlight.

In order to reduce the heat loss by the continents of the atmosphere and the heat loss due to infrared radiation from the surface of the material layer which cannot be mixed with water, the infrared ray is reflected or transmitted through the sunlight rays arranged to form a honeycomb structure. It is possible to use a device of its own known type, which consists of a plurality of absorbing wall members, in which at least a portion of the infrared rays emitted from the surface of the above-mentioned layer in the bottom of the fan or in the sheet are mounted on these wall members. Arrange or suspend them to receive a series of heat absorption.

In order to remove the water to be evaporated from the heated sheet, the water may be removed by a suitable method such as, for example, gravity method, pumping method or thermal siphoning method, but it is preferable to use double heat siphoning method.

Suitable devices known in the art may be used to evaporate the water removed from the heated sheet, but in particular single or multiple stage single or multiple effect evaporators.

It is preferable to perform an evaporation process under the pressure below atmospheric pressure.

Concentrated recovery of water vapor may use a suitable known apparatus, in particular one or more heat exchangers, using a suitable fluid as coolant.

It is preferable to use a material to be purified, for example, seawater, as a coolant, and to flow this water into a heat exchanger, to raise the temperature in the heat exchanger, to send the water to be purified, and the heat exchanger is used for the sheet for spinning. In this way, when concentrating the purified water, a part of the lost heat energy can be recovered and the water to be purified can be raised to increase the yield by this method.

In order to concentrate the water vapor, a chamber with an appropriate cooling device can optionally be used under atmospheric pressure.

A further object of the present invention relates to a purification apparatus by evaporation for carrying out the above-described method.

The device consists of the following structural components: That is, at least a portion of the surface covered sheet and / or contaminated water at least partially covered in a layer of liquid material that is solar transmissive and not miscible with water and has a vapor pressure lower than that of water and at least on the inner surface of the bottom thereof. At least one fan exposed to sunlight, some of which has the property of absorbing sunlight by its accumulation of heat energy; evaporates water heated inside the fan without the aid of solar energy other than that absorbed by the water in the fan. An evaporator arranged to be able to be; And-an apparatus for recovering the evaporated water obtained by concentrating at least a portion of the water vapor produced in this evaporator into a liquid phase.

The evaporator is preferably comprised of at least one single stage evaporator and / or at least one multistage and / or multiple effect evaporator.

In addition, it is preferable that the above-mentioned evaporator can be operated under pressure lower than atmospheric pressure.

It is preferable that at least a part of the inner surface of the pan bottom part is dark.

In order to reduce the heat loss due to heat conduction at the bottom and side walls of the fan, it is advantageous to cover them with a coating having a high thermal insulation effect such as concrete, sponge or pumice. It is also possible to use the above-described thermal insulation coating as other materials such as rock fibers, palm trees, dried seaweeds and the like. In addition, when the device is installed where the soil itself has a good thermal insulation coefficient, such as dry sand, the fan is placed inside the community in the soil, without the thermal insulation coating, by coating a coating that does not permeate the water at the bottom and inner walls of the pan. Insert it.

The device also has at least one screen that transmits at least some of the thermal energy of the sunlight, which is located on at least a portion of the layer of material covering the surface of the sheet and thus providing a stationary air layer on at least part of the layer of material. To be separated.

The device may install at least one body suspended on the surface of the water layer or held at the bottom of the pan by at least one suitable support, which body is preferably made of a transparent plastic material or a material such as glass. It is arranged to transmit at least a portion of the thermal energy of the sunlight and to divide the liquid material layer covering the sheet-like water.

The device is made of a material such as glass, in particular, and it is possible to install a plurality of hollow bodies, such as spherical bodies, that transmit at least some of the thermal energy of sunlight, and these hollow bodies are placed on the sheet-like water. Place it to float.

The apparatus may be provided with at least one reflector, for example an oriented reflecting surface having a planar or concave surface or a plurality of these reflecting surfaces, which are arranged to reflect sunlight on the sheet-like water surface in the fan.

Finally, the device can be equipped with a plurality of wall members that reflect or transmit sunlight and absorb infrared rays, which are arranged to form a honeycomb structure when placed on the bottom of the fan, or the sheet. At least a portion of the infrared rays generated on the surface of the layer of material covering the water of the phase are suspended or floated in the water on the sheet arranged to receive a series of heat absorption on these wall members.

It should be noted that the above described devices can be in a variety of different arrangements. In particular, a fan for heating the water can be supported by a suitable support such that the fan is floating in sea water or the feet of the support stand on the sea floor.

It is possible to obtain a heating fan with a large surface area by economical construction technology. Around this pan, one or several distillation units can be arranged, which can be pre-fabricated in the factory, which in some cases can easily solve the technical challenges imposed on the structure. In addition, the distillation unit may be made of a non-transparent material such as a metal or plastic material that is resistant to corrosiveness, has high mechanical strength and is readily available.

The accompanying drawings show two examples of the apparatus structure according to the present invention and two examples of the fan structure used for heating water by solar heat.

FIG. 1 is a fan 1 having a flat bottom with a surface area of about 10,000 m ^{2 and a} depth of 30 cm, for example, when a hole is drilled in the soil.

The wall and bottom of the fan 1 are preferably made of one or several plastic materials that absorb at least part of the sunlight, for example polyethylene or butyl rubber or tared paper colored with a dark pigment. It is advantageous to place these walls and bottoms in holes in the soil and seal them. It is advantageous to increase the heat absorption effect by making the bottom of the fan 1 and possibly the wall black.

The fan 1 has a sheet 2 of water to be purified, for example seawater. The thickness of this sheet is 3 cm, for example. The surface of the water is covered with a transparent or translucent oil layer 3 having a lower vapor pressure than water, which is colorless or slightly colored. The thickness of this oil layer is suitably between 0.1 and 3 cm.

Under the action of sunlight, the sheet of water 2 is heated, and if the thermal insulation conditions are good, the temperature of the sheet layer 2 of water can be raised to 50-100 ° C. because the evaporation of water in the sheet 2 is prevented. This is because of the effect of the layer 3 on the promotion.

A portion of the water in the fan 1 is removed by the conduit 4 and supplied to the evaporator 5, and a vacuum pump 6 is used in the conduit 4 to maintain the pressure below atmospheric pressure. The evaporator 5 may for example be a plate evaporator or other suitable known evaporator. About 2% of the water introduced into the evaporator 5 is evaporated here, which lowers the temperature of the non-evaporated water to about 10 ° C. The conduit 7 and the liquid pump 8 recycle the water in the non-evaporated portion into the fan 1. The temperature of the water is then about 60 ° C. in conduit 4 and about 50 ° C. in conduit 7.

The steam pipe 9 supplies water vapor generated in the evaporator 5 to the cooler 10, which is a horizontal tube cooler, for example.

Cooling water, for example, seawater having a temperature of 30 ° C., is supplied to the pipe 13 of the cooler 10 by the conduit 11 using the pump 12, and then heated to, for example, 40 ° C. by the conduit 14. , Underwater. Water vapor generated by the evaporator 5 is concentrated on the outer wall of the tube 13, and the demineralized water obtained in this way is the bottom of the inner chamber of the cooler 10, for example, a small water reservoir installed for this purpose ( Collected in 15) and removed by conduit (16) and pump (17).

It should be noted that the vacuum pump 6 removes the gas (oxygen and nitrogen) rate introduced continuously by mixing with the water circulated in the parts of the device having the evaporation and concentration functions. If this gas is not removed, the correct ring function of the device is adversely affected. The oil layer covering the surface of the sheet-like water in the pan 1 keeps the concentration of dissolved gas in the water low by blocking the water from the atmosphere, thereby limiting the amount of gas in the evaporator 5.

A small amount of preheated water as a result of passing through the conduit 13 of the cooler 10 is removed in the conduit 14 by the supply conduit 18 and fed through the conduit 7 to the fan 1. In addition, a small amount of water contained in the fan 1 is continuously removed by the conduit 19 and discharged into the sea to avoid a significant increase in the concentration of salt in the fan 1 produced by evaporation in the evaporator 5. Can be.

The energy required to operate the pump of this unit is considerably less than the cost of demineralized water that can be obtained.

The above apparatus in which the fan 1 having a surface area of 10,000 m ² is provided can easily obtain an integer of 40 to 60 m ³ in Ilsan.

Other parts of the device can be made using readily available materials and the assembly of the device is simple.

Although the above-described apparatus has been described in the case of using a one-stage distillation unit, at least one or more multi-stage distillation units having a single or multiple effects can be used.

The apparatus shown in FIG. 2 has the same fan 1 as in FIG. 1, which likewise has a sheet 2 of water to be purified covered with a translucent oil layer 3.

In the four evaporation chambers 22a, 22b, 22c and 22d in which water to be purified, for example, seawater having a temperature of 25 ° C. at the inlet of the heat exchanger 21a, is arranged in series, In addition, supplying to the fan 1 through the four heat exchangers (for example, tubular heat exchanger) 21a, 21b, 21c, and 21d disposed thereon is performed by the conduit 21. For this purpose, a conduit 23 between the heat exchanger 214 and the fan 1 is used.

After the inside of the fan 1 is heated, the water to be purified is supplied to the evaporation chamber 22d by the conduit 24.

The temperature of the water to be purified is, for example, about 60 ° C. at the inlet of the chamber 226 and the total pressure in the chamber is about 0.14 kg / cm ² .

A vertical baffle 25d disposed opposite the outlet of the conduit 24 in the chamber 22 causes a partial evaporation after agitating and splitting the water entering the chamber.

The steam thus formed is concentrated on the wall of the exchanger 21a, and the purified water obtained is collected in a dish 26d, which is connected to the purified water remover conduit 27 by a conduit not shown here. have.

Some of the water to be purified, which has not evaporated in the chamber 226, is moved to the next chamber 22c, but the total pressure of the chamber 22c is less than the total pressure of the chamber 226. The chamber 22 is arranged in the same manner as the baffle 25d, and a baffle 25c having the same function is provided. The same evaporation and concentration process as in the chamber 22c is carried out in the following chambers 22c and 22a, where the total pressure value is reduced to 0.057 kg / cm ₂ in the chamber 22a.

In the chambers 22b and 22a, baffles 25b and 25a having the same arrangement and function as the current transformer 25d are provided in the same manner.

Purified water obtained by concentration in chambers 22c to 22a was recovered by dishes 26c to 26a and transferred to conduit 27.

Conduit 34 is used to place unconcentrated gas in chambers 22a-22d.

The water that has not evaporated leaves the apparatus at a concentration of salt that is higher than the minimum concentration of water to be purified by conduit 28.

The conduit 20 supplies seawater at a rate of 1000 mg daily at a temperature of 25 ° C. to the above-described apparatus, and when heated to 60 ° C. in the fan 1, 40 m ³ of pure water can be obtained daily.

The structure of the fan shown in FIG. 3 is a reflective side facing the fan in the orientation indicated by arrows 30 indicating the directions of the four basic directions with respect to the device shown in FIG. 3 (the reflective surface is for example aluminum foil). A plurality of planar reflecting elements 29 having a cover). These reflectors are secured around the fan 1 by hinges and can pivot these semi-elements in the direction indicated by the arrow 31 here, specifying these minorities but from horizontal to seasonal. Install a device that can adjust its position to the highest height of the sun.

The fan structure shown in FIG. 4 is a reflective wall 32 having a honeycomb structure on the sheet 2 supported by the bottom of the sheet 2 fan 1 using a series of supports 33. . As for ratio H / D of the dimensions H and D shown in FIG. 4, about 2 is preferable. This wall portion makes it possible to reduce heat loss due to infrared radiation by the water 2 on the sheet.

In the structure of the two types of fans shown in FIGS. 3 and 4 respectively, the preferred thickness of the sheet 2 is about 3 cm and the preferred thickness of the oil layer 3 is 2.5 cm.

Claims (1)

a. Water is applied to the surface to absorb sunlight, making the water into a sheet b. Supplying the sheet with a liquid material having a lower vapor pressure and density than this water to form a layer of liquid material having at least the water permeability on the sheet; c. Irradiate the water with sunlight to preheat d. Further preheat the water to sunlight and produce a stationary air blanket in the layer with the sunlight and a stationary air blanket device, e. Simultaneously performing steps (c) and (d) to produce preheated water f. Feed water preheated from the sheet to the evaporator g. Evaporate at least a portion of the preheated water in this evaporator to produce water vapor; h. This water vapor is fed to the chiller, i. A method for producing purified water, wherein the purified water is condensed to recover purified water.

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