JPS62227492A - Method and apparatus for making pure water - Google Patents

Abstract

PURPOSE:To economically make high quality pure water, by contacting heated general use tap water with air before thermo-vaporation and subsequently degassing the same. CONSTITUTION:A heat transfer pipe 9 is coaxially arranged in an outer pipe 1 and a membrane tube 2 comprising a hydrophobic polymer porous membrane is coaxially arranged in the heat transfer pipe 9. An introducing pipe 11 and a lead-out pipe 12 for cooling water are connected to a cooling water passage and a raw water introducing pipe 4 and a raw water lead-out pipe 5 are con nected to a raw water passage and a lead-out pipe 13 of transmitted water transmitted through the membrane tube and cooled and condensed by the wall of the heat transfer pipe is connected to a steam diffusion space 10. Further, a heater 31 for heating tap water and an air blow pipe 32 for blowing air in general tap water are inserted in the membrane tube. Then, air is blown into general use tap water under heating to degas dissolved gas and, at the same time, thermo-vaparation treatment is applied to tap water in this state.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for producing pure water from general tap water, and more specifically, to purify general tap water by treating general tap water by a so-called thermopervaporation method. A method for easily producing high quality pure water by bringing ordinary tap water into gas-liquid contact with air under heating and degassing dissolved gas, and a simple method for producing water. related to equipment.

(Prior Art) Various methods have been proposed and put into practical use for producing pure water using rise water as raw water. As such a method, for example, prefiltration of general tap water as raw water,
A method of ion exchange treatment, distillation, and further filtration is known. Such a method usually results in a conductivity of 1.0.
Pure water of μS/cm or less can be obtained. Depending on the use of pure water, further processing may be added. For example, in the case of producing pure water for medical use, chemical treatment or sterilization with ultraviolet rays may be performed.

In the present invention, -a tap water usually refers to river water, well water,
Including tap water, industrial water, pharmacopoeia regular water, etc., and generally contains Ca,
Dissolved substances such as cations such as Mg, Na, etc., anions such as chlorine ions, sulfate ions, bicarbonate ions, organic substances decomposed by organisms, dissolved gases such as oxygen, carbon dioxide, nitrogen, chlorine, ammonia, etc. Contains suspended substances such as microorganisms, inorganic and organic particles, and microorganisms as impurities. Also,
In the present invention, pure water generally refers to, for example, water used for preparing standard solutions for analytical instruments, cleaning instruments, culturing microorganisms, etc., water for boilers, and purified water specified in the Japanese Pharmacopoeia. Including hospital water such as water, distilled water for syringes, and sterile water.

According to the conventionally known method of producing pure water from general tap water, in order to remove various impurities with different properties as described above, basically ion exchange is used to remove inorganic substances. , distillation, membrane separation, etc., as well as filtration to separate microorganisms and fine particles, and in addition to these separation operations, various pre-treatments and post-treatments are added to complete the entire pure water production process. It consists of

However, producing pure water through a large number of steps as described above not only increases production costs, but also makes it difficult to maintain and manage the production equipment. Moreover, such a multi-step method requires storage of the treated water between each step, and there is a risk that microorganisms will grow during storage.

(Object of the Invention) In order to solve the above-mentioned problems in the production of pure water from rise water, the present inventors have focused on the so-called thermopervaporation method, in particular - We have found that, with the exception of dissolved gases, all of the above-mentioned impurities can be removed by thermopervaporation, and thus: The present invention was achieved based on the discovery that pure water having a quality equal to or higher than that of the conventional method described above can be produced very easily and economically by treating the water with the same or higher quality.

(Structure of the Invention) The method for producing pure water according to the present invention includes heating ordinary tap water,
Raw water is brought into contact with one side of a hydrophobic polymer porous membrane that allows water vapor to pass through but does not allow water to pass through, and water vapor is generated from this raw water, which is passed through the other side of the porous membrane and cooled. In the thermopervaporation method, in which permeated water is obtained as pure water by condensation, the heated common tap water is brought into gas-liquid contact before or during the thermopervaporation, and the rise water is deaerated. It is characterized by

-i Dissolved gases contained in tap water cannot be removed even by the thermopervaporation method described below.
It mixes into the permeated water obtained as pure water by the thermopervaporation method, and a part of it dissociates, leading to an increase in its electrical conductivity and degrading the quality of pure water. In the present invention, dissolved gas refers to carbon dioxide gas (including carbonic acid. Hereinafter,
These are sometimes called carbonic acid components. ) as the main component,
In addition to these, it refers to oxygen, nitrogen, chlorine, ammonia, organic volatile components, etc. - Rise water contains a relatively large amount of carbonic acid components compared to other dissolved gases, usually several ppm.
It is contained in an amount of about several tens of ppm. Dissolved gases other than carbonic acid components are only contained in a very small amount. For example, about 2p
When general tap water containing pm carbonate components is treated by the thermopervaporation method, the permeated water obtained has an electrical conductivity of more than 1 μS/cm.

Therefore, the present inventors conducted a detailed study on the relationship between the carbonic acid components contained in general tap water and the conductivity of permeated water obtained by the thermopervaporation method, and found that -
Reduce carbon dioxide content in ship water to 2 ppm or less, preferably 1 ppm or less
ppm or less, it is possible to obtain passing water with a Mat degree of 1.0 μS/cm or less using the thermopervaporation method, and on the other hand, by bringing heated general tap water into gas-liquid contact, its carbonic acid component can be removed. It was discovered that it is possible to reduce the amount of carbon dioxide to 2 ppm or less.

That is, according to the method of the present invention, in order to remove the above-mentioned dissolved gases and carbonic acid components by degassing, -C water is heated and brought into gas-liquid contact with air, or Purified water with a mold temperature of 1.0 μS/am or less can be obtained by processing with a thermopervaporation method while making gas-liquid contact.

In the present invention, the above-mentioned gas-liquid contacting method includes, for example, a method using a wet wall tower or a countercurrent contact tower, a method of spraying general tap water into the atmosphere from a nozzle, and a method of spraying air into the ship's water in the form of fine bubbles. However, in the thermopervaporation method, it is necessary to use heated general water, and on the other hand, the degassing efficiency by gas-liquid contact decreases as the temperature of the general water field increases. Therefore, in the present invention, air is blown into heated general water,
Gas-liquid contact is most advantageous.

Next, the thermopervaporation method in the method of the present invention will be explained.

The thermopervaporation method generally involves heating raw water to generate water vapor, and selectively passing this water vapor through a porous membrane made of a hydrophobic polymer.
This is cooled and condensed to obtain permeated water as pure water.

In order to treat general tap water using such a thermopervaporation method, one of the following methods can be used.

The first method is to bring raw water at a predetermined temperature into contact with one side of a hydrophobic polymer porous membrane that allows water vapor to pass through but does not allow water or solutes to pass through, and the other side of this porous membrane is exposed to water from the membrane surface. Heat transfer walls maintained at a predetermined low temperature are provided at appropriate intervals, and water vapor generated from the raw water and transmitted through the porous membrane is cooled on the heat transfer walls and condensed to obtain permeated water. be.

The second method involves contacting one side of the hydrophobic polymer porous membrane with raw water at a predetermined temperature as described above, and contacting the other side with a predetermined low-temperature cooling medium, such as pure water for cooling. By doing so, water vapor generated from raw water and passed through the porous membrane is directly cooled and condensed with pure water as a cooling medium, and this is obtained in the cooling medium.

In any of the above methods, the polymer porous membrane is
It must be hydrophobic to water, and must have the property of not allowing microorganisms such as molds and fungi to pass through, as well as water itself, but allowing water vapor to pass through.

Therefore, such hydrophobic polymer porous membranes usually have 0.0
5-50 μm, preferably 0.1-10. It is preferable to have micropores of about czm and have a porosity of 50% or more. In addition, although the film thickness is not particularly limited,
Usually, it is about 1 μm to 2B, preferably about 50 μm to 1 day.

Therefore, in the present invention, as such a porous membrane, a porous membrane made of a fluororesin such as polytetrafluoroethylene resin is hydrophobic and has excellent heat resistance. Alternatively, it is particularly preferably used because common tap water can be sterilized at high temperature at the same time during membrane treatment. Also preferably used is a porous membrane obtained by extrusion molding a solution or melt of a fluororesin such as vinylidene fluoride resin or ethylene-tetrafluoroethylene copolymer resin. However, when a porous membrane made of a hydrophilic resin such as polysulfone or cellulose resin is coated with a water-repellent resin such as a fluororesin or silicone resin to provide a hydrophobic porous surface,
These resin films can also be used.

Next, a thermopervaporation device suitable for use in the method of the present invention will be described based on the drawings.

FIGS. 1 and 2 show an example of a thermopervaporation device that can be suitably used in the method of the present invention.

That is, the membrane tube 2 made of the above-mentioned hydrophobic polymer porous membrane is coaxially disposed inside the outer tube 1, and the raw water at a predetermined temperature is placed between the outer tube and the membrane tube. A raw water passage 3 is formed. Therefore, the outer tube preferably has heat retaining properties, and is made of resin, for example. A raw water inlet pipe 4 and a raw water outlet pipe 5 are connected to the raw water passage 3, and the raw water heated to a predetermined temperature by a heater 6 installed in these pipes as necessary is passed through the raw water circuit through the pipes 4 and 5. It is circulated and distributed. Raw water is appropriately replenished into the raw water circuit through a supply pipe 8 equipped with a valve 7, and a portion of the raw water is discharged from the raw water circuit as necessary through a discharge pipe (not shown).

A heat transfer tube 9 is further disposed coaxially inside the membrane tube 2, and is spaced at an appropriate distance so that a vapor diffusion space 10 exists between the tube and the membrane tube. It is preferable for the vapor diffusion space to be narrow from the point of view of water vapor condensation efficiency, but if it is too narrow, it will actually create a flow resistance for permeated water, so it is usually preferably about 0.2 to 511 mm. The heat transfer tube is preferably a thin-walled stainless steel tube that has high heat conductivity and is free from ion extraction. This heat transfer tube includes an inlet pipe 1 for the cooling medium.
1 and an outlet pipe 12 are connected, and a cooling medium such as cooling water is circulated within the heat transfer tube.

Further, connected to the vapor diffusion space is an outlet pipe 13 for permeated water that has permeated through the membrane tube, been cooled by the heat exchanger tube, and condensed.

Note that, if the porous membrane constituting the membrane tube has low strength, it may be supported on an appropriate support (not shown). Such a support only needs to be able to reinforce the porous membrane and allow water vapor to pass therethrough, and for example, a woven or nonwoven fabric made of polyamide or a porous tube made of ceramic is preferably used.

Further, as shown in FIG. 3, the thermopervaporation device includes a plurality of membrane tubes 2 disposed inside an outer tube 1, each membrane tube having a heat transfer tube 9 inside, and an outer tube and each membrane tube. The space between the pipe and the pipe may be configured to be the raw water passage 3.

4 and 5 also show an example of a thermopervaporation device for carrying out the first method, and the same parts as in FIG. 1 are given the same reference numerals. That is, the membrane tube 2 is disposed coaxially within the outer tube 1, and the raw water passage 3 is formed between the outer tube and the membrane tube.
It is the same as the thermopervaporation device shown in the figure, but
In this device, a spacer 14 is disposed on the inside of the membrane tube 2 in contact with it, and a heat exchanger tube 9 is further disposed on the inside of this spacer in contact with it. That is, since the spacer is cooled by the heat transfer tube, the spacer itself forms a cooled vapor diffusion space and also forms a passage for permeated water. Therefore, the steam generated from the raw water and permeated through the membrane tube is cooled by the spacer and the heat transfer tube, and the spacer is communicated with the condensed permeated water outlet tube 13.

This spacer must be porous so that the steam that has passed through the membrane tube can pass through to the heat transfer tube, and must also have liquid permeability in at least a predetermined direction for water that has been cooled and condensed by the heat transfer wall. Furthermore, it is preferable that the material has excellent thermal conductivity. In the illustrated apparatus, the spacer needs to have liquid permeability at least in the vertical direction so that the generated permeated water can flow down in the vertical direction.

Of course, the spacer may be bonded in advance to the porous membrane, the heat exchanger tube surface, or both.

Examples of the spacer include woven fabrics, non-woven fabrics made of 10 to 1000 meshes of natural or synthetic fibers, such as polyethylene, polyester, polyamide, etc.
Carbon fiber cloth, metal mesh, etc. are preferably used. The thickness of the spacer is not particularly limited, but if it is too thick, it will actually reduce the steam condensation efficiency, so normally,
A range of 5 or less, particularly 0.2 to 3 is preferred. That is,
By using a spacer with a small thickness, the interval between the vapor diffusion spaces can be reduced, and at the same time, the efficiency of condensing water vapor and the acquisition rate of pure water as permeated water can be increased.

An inlet pipe 4 and an outlet pipe 5 for general tap water as raw water are connected to the raw water passage 3, and a heater 6 is provided in this pipe as necessary. It is the same as in the previous device that raw water is replenished into the raw water circuit through a supply pipe 8 equipped with a valve 7. Further, the heat exchanger tube is connected to the inlet tube 11 and the outlet tube 12 for the cooling medium, as described above, and the cooling medium is circulated within the heat exchanger tube.

In the thermopervaporation apparatus shown in FIGS. 1 and 2, raw water at a predetermined temperature is introduced into the raw water passage 3, and the water vapor generated from the liquefied water passes through the membrane tube 2 and enters the steam space 10. The permeated water is then cooled on the surface of the heat exchanger tube 9 to produce permeated water, which flows down the surface of the heat exchanger tube and is led out of the apparatus through the passed water outlet tube 13. Fine particles and microorganisms in the raw water are blocked from permeation by the membrane tube and remain in the raw water.

According to the thermopervaporation device shown in FIG. 4, water vapor generated from raw water passes through the membrane tube 2, is cooled by the spacer 14 and the heat transfer tube 9, is condensed, and flows down the spacer to lead out the passing water. It is led out of the device through a pipe 13.

6 and 7 show another example of a thermopervaporation device, in which the same parts as in FIG. 1 are given the same reference numerals.

A membrane tube 2 made of a hydrophobic polymer porous membrane as described above is disposed coaxially within the outer tube 1, and a raw water passage 3 is formed between the outer tube and the membrane tube. Raw water at a predetermined temperature is passed through the membrane tube, and pure water is passed through the membrane tube as a cooling medium. That is, raw water and pure water as a cooling medium are brought into contact through the membrane tube. An inlet pipe 4 and an outlet pipe 5 for flowing raw water are connected to the raw water passage 3, and similarly, a membrane pipe 2 is connected to the raw water passage 3.
An inlet pipe 11 and an outlet pipe 12 for circulating a cooling medium are also connected to the pipe.

According to this second thermopervaporation device,
Water vapor generated from raw water and permeated through the membrane tube wall is immediately cooled and condensed in pure water as a cooling medium, and is recovered in pure water as a cooling medium.

In the same way as described above, raw water is replenished from the supply pipe 8 as necessary, heated by the heater 6, and then supplied to the pipes 4 and 5.
The cooling medium is circulated through the cooling medium circuit while being cooled to a predetermined temperature by the cooler 14 provided in the cooling medium circuit □ as necessary. The permeated water is taken out of the apparatus through the take-out pipe 15.

According to this second thermopervaporation device,
Since raw water at a predetermined temperature and pure water as a cooling medium are brought into direct contact through the membrane tube, the water vapor generated from the raw water is immediately cooled and condensed by the pure water as a cooling medium. Collected in pure water. Therefore, not only the vapor transmission rate is high, but it can also be made smaller than a unit device with a vapor space between the membrane tube and the heat transfer wall, and the effective membrane area per unit volume is large, so it is possible to efficiently purify water. can be obtained.

Although not shown, as a modification of the thermopervaporation device shown in FIG. The outside space may be formed to form a raw water passage.

In addition, in the case of any of the above-mentioned thermopervaporation devices, the present invention has been described in detail assuming that raw water is passed through the raw water passage 3 between the outer tube and the membrane tube, and a cooling medium is circulated within the membrane tube. However, it goes without saying that the cooling medium may be passed through the raw water passage, while the raw water may be made to flow through the cooling medium passage.

When a thermopervaporation device has a spacer between the membrane tube and the heat transfer tube, the spacer itself is also cooled by the low-temperature heat transfer wall, so the vapor that permeates through the membrane is absorbed by the spacer and the heat transfer wall. It is immediately cooled and condensed, and as a result, the condensation rate of the steam increases, making it possible to obtain pure water as permeated water with high efficiency.

In addition, in all of the illustrated thermopervaporation devices, the raw water passage or the cooling medium passage is formed in an annular shape. , at least one pair are arranged facing each other with or without a vapor diffusion space therebetween;
By enclosing each passage in a suitable container corresponding to the outer tube and connecting a circuit for the Wi ring of raw water or cooling medium to each passage, the cross section can be adjusted to correspond to each of the above-mentioned thermopervaporation devices. It is possible to obtain a thermopervaporation device having a rectangular raw water passage and a cooling medium passage.

Furthermore, by arranging the membrane wall and the heat transfer wall in contact with each other via a spacer, a thermopervaporation device corresponding to FIG. 4 can be obtained.

It will be clear that such a thermopervaporation device can also be suitably used to carry out the method of the present invention.

FIG. 8 shows an example of an apparatus configuration for carrying out the method according to the present invention. This device includes: a heating deaeration tank 21 and a thermopervaporation device 22 for heating and deaerating rise water; the heating deaeration tank 21 includes a heater 23 and an air blowing pipe 24; ing. - The rise water is led to the heating deaeration tank 21 through a suitable pipe line 25, where air is blown under heating to remove dissolved gas, and then the raw water passage in the thermopervaporation device 22 3, and here, as described above, permeated water as pure water can be obtained from the outlet pipe 13.

Further, according to the method of the present invention, while heating -C clean water,
Pure water can also be obtained by thermopervaporation treatment. A simple device for carrying out such a method is to degas heated general water and bring it into contact with one side of a hydrophobic polymer porous membrane that allows water vapor to pass through but not water. In a pure water production device that generates water vapor from raw water, transmits it to the other side of the porous membrane, cools it on the heat transfer wall, and condenses it to obtain permeated water as pure water. An outer tube, a heat transfer tube, and a membrane tube are arranged coaxially, the inside of the membrane tube is a raw water passage, and the annular gap between the heat transfer tube and the membrane tube is a vapor diffusion space where water vapor from the raw water diffuses and condenses. The annular gap between the outer tube and the heat transfer tube is used as a cooling water passage, and the membrane tube is formed from the hydrophobic polymer porous membrane. It is characterized by being equipped with a heater, an air blowing pipe for bringing raw water into gas-liquid contact and degassing it, and an opening for degassing.

An embodiment of the apparatus according to FIGS. 9 and 10 is shown. 1st
Elements that are the same as in the figures have been given the same reference numerals. That is,
A heat transfer tube 9 is disposed coaxially within the outer tube 1, and a membrane tube 2 made of a hydrophobic polymer porous membrane as described above is coaxially disposed within this heat transfer tube 9. An annular gap between the outer tube and the heat transfer tube is formed in the cooling water passage 16, and an annular gap between the heat transfer tube and the membrane tube is formed in the vapor diffusion space 10. Four inlet pipes 11 and four outlet pipes 12 for cooling water are connected to the cooling water passage, and an inlet pipe 4 for raw water is connected to the raw water passage.
and the outlet pipe 5 are connected, and the vapor diffusion space 1
0 is connected to a discharge pipe 13 for permeated water that has permeated through the membrane tube, been cooled and condensed on the wall of the heat transfer tube.

In the illustrated device, a heater 31 for heating general water and an air blowing pipe 32 for blowing air into the general water are further inserted into the membrane tube, and
It communicates with an air port 33 in order to diffuse the degassed dissolved gas into the atmosphere together with the air.

According to this apparatus, pure water can be easily obtained because air is blown into the heated water to degas the dissolved gas and at the same time thermopervaporation treatment is performed.

Further, according to the present invention, pure water is obtained from general tap water by the thermopervaporation device shown in FIG. 8, and cooling water from the thermopervaporation device is heated and/or air and After bringing into liquid contact, preferably by blowing air under heating to bring into gas-liquid contact, this can be used as raw water and subjected to thermopervaporation treatment to obtain pure water. Since the cooling water in the thermopervaporation method is heated and this heated cooling water is used as raw water, it has excellent thermoeconomic efficiency.

In the above methods and devices, the higher the heating temperature of the raw water, the more permeated water can be obtained by thermopervaporation, so the heating temperature for deaeration and the heating temperature for thermopervaporation are usually 50°C. It is preferable that the temperature is at least ℃. Furthermore, the temperature of the cooling water in thermopervaporation is preferably lower, but is usually about 10 to 40°C.

Note that, if necessary, the thermopervaporation device can be configured in multiple stages, and the permeated water from the first device can be further subjected to thermopervaporation treatment in the second stage device.

(Effects of the Invention) As described above, according to the method of the present invention, - By gas-liquid contact, heated general tap water is heated before or during the treatment of rise water by the thermopervaporation method, and the main carbonic acid components are At the same time, other dissolved gases are removed, and the above-mentioned dissolved substances such as cations and organic substances, as well as suspended substances such as fine particles and microorganisms, are substantially completely removed by thermopervaporation treatment. Therefore, according to the method of the invention,
High quality pure water with an electrical conductivity of 1.0 μS/cI11 or less can be easily and economically produced through a few steps.

Furthermore, according to the method of the present invention, unlike reverse osmosis, which uses a pressure difference as a driving force, it uses a temperature difference as a driving force, so pressurization is not required, and it can also be used with general tap water that has been heated and deaerated. According to the method of processing the thermovar heparation,
Because high-temperature general water can be treated directly using the thermopervaporation method, it not only has excellent thermoeconomic efficiency, but also suppresses the growth of microorganisms in the membrane and general water during the treatment process. It is also possible to sterilize the membrane and general water at high temperature at the same time. Furthermore, since a hydrophobic membrane is used, there is no clogging of the membrane or concentration polarization, and - highly purified water can be efficiently obtained from water.

In addition, according to the device of the present invention, the -i tap water is degassed by gas-liquid contact while being heated and subjected to thermopervaporation treatment, so the device is very simple and efficient (high quality). Pure water can be produced.

(Example) Examples of the present invention are listed below.

Example 1 Using the apparatus shown in FIG. 8, pure water was produced using Ibaraki City tap water as water. The properties of this rise water are as follows.

Na 10,7 try/IK
2.08■/iCa
14.2 mg/j! Mg
3.84■/l carbon dioxide gas 8.
8 ■/l Chlorine ion 16.9 ■/1
Sulfate ion 18.4 ■/l silica
18.2 ■/Il total phosphorus
0.05■/l Free chlorine 1.0 p
pm or less Ammonia nitrogen 0.5 ppm or less Electrical conductivity 180 μS/In a CIII heating deaeration tank, the above Ibaraki city tap water 101 was heated at a temperature of 80°C.
After heating it to a temperature of 517 min, air was blown into it for 10 minutes to bring it into gas-liquid contact, and then it was supplied to a thermopervaporation device through a pipe at a rate of about 51 min. Cooling water at a temperature of 20° C. was supplied to the cooling water passage at a rate of 54′/min.

The amount of carbon dioxide gas in general tap water after deaeration is 0.5 ppm, and the device supplies 60% of pure water with an electrical conductivity of 0.8 μS/cm.
It was obtained at a rate of 0 cc/min.

The thermopervaporation device uses a flat membrane made of a polytetrafluoroethylene porous membrane lined with a porous polyamide woven fabric, and a spacer with a thickness of 0.5 m.
This is a flat cell device constructed by stacking polyamide nets and arranging cooling water passages with heat transfer walls made of stainless steel plates on the surface of the spacer, and the porous membrane has an average pore diameter of 0.
．． It has micropores of 2 μm, a porosity of 80%, and an effective membrane area of 400 cJ in the device.

Example 2 As shown in Fig. 9, a stainless steel heat transfer tube and a membrane tube made of a polytetrafluoroethylene porous membrane lined with FEP resin were coaxially disposed inside a resin outer tube, and the membrane The device was constructed by inserting a heater and an air blowing tube into the tube. The membrane tube is made of a porous membrane with a porosity of 80% having micropores with an average pore diameter of 0.2 μm, and the effective membrane area in the device is 890cm111.

In this device, general tap water is supplied to the raw water passage at a rate of 1.81/min, and while it is heated to approximately 80°C with a heater, air is blown in at a rate of 31/min. Cooling water at a temperature of 15° C. was supplied to the water passage at a rate of 36/min.

The amount of carbon dioxide gas in the general tap water in the membrane tube is 0.5 ppm, and the device pumps pure water with an electrical conductivity of 0.8 μS/cm.
It was obtained at a rate of 0 cc/min.

In addition, when the same treatment was carried out except that air was not blown into the membrane tube, the obtained permeated water had an electric power of 1.4 degrees.
It was 3 μS/CIn.

Example 3 Cooling water from the thermopervaporation "AH" shown in FIG. 9 was heated and degassed, and this was used as raw water and subjected to thermopervaporation treatment to produce pure water.

In a thermopervaporation device, general tap water is supplied to the raw water passage at a rate of 1,817 min, and while it is heated to approximately 80°C with a heater, air is blown at a rate of 2/min, and the other , the cooling water passage has a temperature of 20°C.
．． 7 A/min, collecting cooling water at about 60°C from the device and heating it to about 85°C, at 31/min.
After deaerating the water by blowing air into it at a rate of 1.5 min, it was supplied as raw water to a thermopervaporation device.

The amount of carbon dioxide gas in the general tap water in the membrane tube was 0.08 ppm, and pure water with an electrical conductivity of 0.6 μS/cm was obtained from the device at a rate of 30 cc/min.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of a thermopervaporation device used in the method of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is a different device. 4 is a longitudinal sectional view showing still another device, FIG. 5 is a sectional view taken along line B-B in FIG. 4, and FIG. 6 is a longitudinal sectional view showing still another device. FIG. 7 is a sectional view taken along line CC in FIG. 6. FIG. 8 is a diagram showing an example of the configuration of an apparatus for implementing the method of the present invention, FIG. 9 is a sectional view showing an embodiment of a preferred apparatus for implementing the method of the present invention, and FIG. FIG. 1...Outer tube, 2...Membrane tube, 3...Raw water passage, 9.
... Transfer pipe, 10... Vapor diffusion space, 13... Pure water outlet pipe, 14... Spacer, 15... Cooling water outlet pipe, 16... Cold moon water passage, 21...・Heating deaeration tank, 22
... thermopervaporation device, 23 ... heater, 24 ... empty blowing pipe, 25 ... pipe line, 3
1... Heater, 32... Air blowing pipe, 33...
air vent. Patent applicant Nitto Electric Industry Co., Ltd. Moxibustion agent Patent attorney Itsu Makino f! :" :I corner

Claims (3)

[Claims] (1) Heated general tap water is brought into contact with one side of a hydrophobic polymer porous membrane that allows water vapor to pass through but does not allow water to pass through as raw water, generates water vapor from this raw water, and transfers it to the above porous membrane. In the thermopervaporation method, which permeates through the other side, cools and condenses, and obtains permeated water as pure water, ordinary tap water heated before or during the thermopervaporation is converted into a gas-liquid. A method for producing pure water characterized by deaerating general tap water by contacting it. (2) The method for producing pure water according to claim 1, characterized in that air is blown into heated general tap water to bring it into gas-liquid contact. (3) While degassing the heated general water, it is brought into contact with one side of a hydrophobic polymer porous membrane that allows water vapor to pass through but does not allow water to pass through, to generate water vapor from this raw water and transfer it to the above-mentioned porous water. In a water purification device that permeates through the other side of the membrane, cools and condenses on the heat transfer wall, and obtains permeated water as pure water, the outer tube, heat transfer tube, and membrane tube are coaxially connected from the outside. The inside of the membrane tube is a raw water passage, the annular gap between the heat transfer tube and the membrane tube is a vapor diffusion space where water vapor from the raw water diffuses and condenses, and the annular gap between the outer tube and the heat transfer tube is The void is used as a cooling water passage, and the membrane tube is formed from the hydrophobic polymer porous membrane, and the membrane tube has a heater inside it for heating the raw water, and the raw water is brought into gas-liquid contact for deaeration. 1. A pure water production device comprising an air blowing pipe for deaeration and an opening for deaeration.