JPS62216695A - Method and apparatus for producing pure water - Google Patents

Abstract

PURPOSE:To easily and economically produce pure water having high quality by preliminarily removing a dissolved gas and volatile materials from general service water then treating the water with a thermovaporation method. CONSTITUTION:The general service water contg. the volatile components (e.g.; CO2 and H2CO3) which generate the gas when heated is subjected to deaeration together with the dissolved gas by a heating deaeration method, etc., by which the above-mentioned volatile components are removed. The general service water subjected to the above-mentioned stage, i.e., the raw water in a passage 3 is brought into contact with one face side of a porous hydrophobic polymer membrane 2 which allows the permeation of steam but prohibits the permeation of water at a prescribed temp. so that the steam is generated from the raw water. The steam is passed through the membrane 2 to the other side and is cooled and condensed to obtain the permeated water as pure water. The porous membrane consisting of a fluoroplastic such as polytetrafluoroethylene resin is preferably used as the above-mentioned porous membrane. As a result, the high-quality pure water having <=1.0mus/cm degree of electrolytic dissociation is easily and economically produced.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method and apparatus for producing pure water from shipboard water, and more specifically, the present invention relates to a method and apparatus for producing pure water from shipboard water, and more specifically, for purifying ordinary water by treating common water by a so-called thermopervaporation method. The present invention relates to a method for easily producing high-quality pure water by including a step of removing a dissociable gas as a pretreatment in a method for producing water, and a simple device for the same.

(Prior Art) Various methods for producing pure water using -1 clean water as raw water have been proposed and put into practical use. 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, - Onboard 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 ions such as Mg5Na, Ni, anions such as chloride ions, sulfate ions, hydrogen carbonate ions, organic substances decomposed by living organisms, dissolved gases such as oxygen, carbon dioxide, nitrogen, chlorine, ammonia, etc. Contains suspended substances such as 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 shipboard water, the present inventors have focused on the so-called thermopervaporation method, in particular - It has been found that, with the exception of dissolved gases and volatile substances, all of the above-mentioned impurities can be removed by thermopervaporation, and thus, as a pretreatment, - previously removed dissolved gases and volatile substances from shipboard water; The inventors have discovered that if the water is then treated using a thermopervaporation method, it is possible to produce pure water with a quality equivalent to or higher than that of the conventional method described above, very easily and economically, and based on this, the present invention has been made. This is what we have come to.

(Structure of the Invention) A first method for producing pure water according to the present invention is a method for producing pure water from common clean water, which includes: (a) dissolving common clean water containing volatile components that generate gases when heated; A first step of degassing with gas to remove the volatile components, and (bl) a hydrophobic polymer porous membrane that allows water vapor to pass through but not water. The raw water is brought into contact with one side at a predetermined temperature, water vapor is generated from this raw water, and this is permeated through the other side of the porous membrane, cooled and condensed to obtain permeated water as pure water. It is characterized by including two steps.

A second method for producing pure water according to the present invention is a method for producing pure water from ordinary tap water, which includes: (a) bringing ordinary tap water containing volatile components that generate gas upon heating into contact with an anion exchange resin; a first step of removing the volatile components, and (b) a predetermined layer on one side of the hydrophobic polymer porous membrane that allows water vapor to pass through but not water. A second step includes contacting the raw water as raw water at a temperature of It is characterized by

Volatile components and dissolved gases cannot be removed even by the thermopervaporation method described later, and they are mixed into the permeated water obtained as pure water by the thermopervaporation method, and some of them dissociate, reducing its electrical conductivity. This leads to an increase in the water content and reduces the quality of pure water. In the present invention, volatile components refer to components that generate gas when heated, and in particular, carbon dioxide gas (CO□) and carbonic acid (11□C(
h) (Hereinafter, these may be referred to as carbonic acid components.

)including.

Compared to other volatile components, these are commonly found in tap water.
It is particularly contained in a large amount, and is usually contained in about several tens of ppm. Volatile components other than carbonic acid components and dissociable dissolved gases include, for example, ammonia, chlorine, etc., and are normally contained in only a small amount in general tap water. Furthermore, carbonate ions (CO3"-) do not generate carbon dioxide gas even when heated. In this way, when general tap water containing about several tens of ppm of carbonic acid components is treated using the thermopervaporation method, Normally, permeated water contains carbonic acid components at a concentration of 0.5 ppm or more, and the conductivity is 1 μs.
/am.

Therefore, the present inventors conducted a detailed study on the relationship between the carbonic acid components contained in -a clean water and the conductivity of permeated water obtained by the thermopervaporation method, and found that the carbonic acid components in general tap water By setting 5ρpr++ or less, the conductivity can be reduced to 1.0μ by thermopervaporation method.
It has been found that it is possible to obtain permeated water of less than S/cm. Considering the presence of other volatile components and dissolved gases, it is preferable that the amount of carbonic acid components in general tap water be 1 ppm or less.

In the first method of the present invention, any conventionally known degassing method can be used to remove the above-mentioned dissolved gases and volatile substances, especially carbonic acid components, by degassing. Examples of degassing methods include aeration, heating degassing, vacuum degassing, blowing inert gas, and ultrasonic irradiation.

In particular, when this deaerated general water is treated using the thermopervaporation method, the general water needs to be heated, so heating degassing is the most advantageous deaeration method. be.

It has also been found that ultrasonic irradiation is particularly effective in removing carbonic acid from common tap water. For example, by irradiating ordinary tap water in tz with ultrasonic waves of 3 W/- or higher and 0.2 MHz or higher for 5 minutes or more, the ordinary tap water becomes partially atomized, and carbonic acid components are effectively removed. .

In the second method of the present invention, general tap water is subjected to anion exchange treatment and then thermopervaporation treatment in order to remove the above-mentioned dissolved gases and volatile substances, particularly carbonic acid components.

Of course, it is well known that ion exchange resins are used to treat -i clean water, but conventionally, the purpose of ion exchange treatment was to remove all the ions contained in general clean water. As a result, the ion exchange resin is quickly saturated, and the amount of general tap water treated by a unit amount of the ion exchange resin is extremely small. Furthermore, in the conventional method,
In the treatment of general tap water, anion exchange resins are rarely used alone; in most cases, they are used in combination with cation exchange resins.

On the other hand, according to the second method of the present invention, the first
In the process, the anion exchange resin substantially completely removes the carbonic acid components in general tap water, so similar to the degassing method described above, the subsequent thermopervaporation immediately produces high-quality pure water. can be obtained.

That is, according to the present invention, nonvolatile ions are substantially completely removed in the thermopervaporage conditioning treatment of general tap water after anion exchange treatment, so that in the first step, volatile components are removed. It is sufficient to remove only anions, especially carbonic acid components, which are contained in large amounts in general tap water.
Therefore, a large amount of general tap water can be treated with a unit amount of anion exchange resin.

Moreover, it has the advantage of not requiring treatment with a cation exchange resin.

The anion exchange resin that can be used in the present invention is not particularly limited as long as it has an anionic dissociative group. An anion exchange resin in which the hydroxyl group is ion-exchanged is preferred. However, in the present invention, not only the above strong base type anion exchange resin but also a weak base type anion exchange resin can be used as needed.

Next, the thermopervaporation method as the second step 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 by the heat transfer wall soil and condensed to obtain permeated water. .

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. czm, preferably about 0.1 to 10 μm, and preferably has a porosity of 50% or more. In addition, although the film thickness is not particularly limited,
Usually, it is about 1 μm to 2 μm, preferably about 50 μm to 1 μm.

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 carrying out the second step 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 exchanger tube 9 is further disposed coaxially inside the membrane tube 2, and is spaced at an appropriate distance so as to have a vapor diffusion space 10 between it and the membrane tube. It is preferable for the vapor diffusion space to be narrow in terms of the 'cE compression efficiency of water vapor, but if it is made too narrow, it will actually create a resistance to the flow of permeated water.
Usually, about 0.2 to 51 is suitable. The heat transfer tube is preferably a thin-walled stainless steel tube that has high heat conductivity and is free from ion extraction. An inlet pipe 11 and an outlet pipe 12 for a cooling medium are connected to the heat exchanger tube, and a cooling medium such as cooling water is circulated through the heat exchanger 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.

In addition, as shown in FIG. 3, the thermopervaporation device C includes a plurality of membrane tubes 2 disposed inside the outer tube 1, each membrane tube having a heat transfer tube 9 inside, and the outer tube and each membrane. 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 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 device, 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,
5 + u or less, particularly preferably in the range of 0.2 to 3 n. 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 water vapor generated from the raw water passes through the membrane tube 2 and reaches the steam space 10. The permeated water is cooled on the surface of the heat exchanger tube 9 to generate 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. Microorganisms in the raw water are prevented from permeating through the membrane tube and remain in the raw water.

According to the thermopervaporation device shown in FIG. 4, water vapor generated from raw water permeates through the membrane tube 2, is cooled by the spacer 14 and the heat transfer tube 9, condenses, and flows down the spacer to cause the permeated water to rise. It is led out of the device through the outlet 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.
A straight pipe 11 and a lead-out pipe 12 are also connected to the cooling medium for circulating the cooling medium.

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 a cooler 14 provided in the cooling medium circuit as necessary, and a part of the cooling medium is circulated through the obtained permeated water. It is taken out of the apparatus from the take-out pipe 15 together with water.

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. 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.

In addition, 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 has passed 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 circulation of raw water or a cooling medium to each passage, a cross section corresponding to each of the above-mentioned thermopervaporation devices can be obtained. It is possible to obtain a thermopervaporation device having a rectangularly extending 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.

As described above, in the first method of the present invention, it is advantageous to heat and deaerate common tap water and then treat it by thermopervaporation. A configuration diagram of an apparatus suitable for carrying out such a method is shown in FIG.

This device is a heater that heats and deaerates general tap water! 2
1 and a thermopervaporation WW 22, general tap water is led to a heating container 21 through an appropriate pipe line 23,
After being heated and boiled and deaerated, it is supplied to the raw water passage 3 in the thermopervaporation device 22, where, as described above, permeated water as pure water can be obtained from the outlet pipe 13. .

In particular, the apparatus for easily carrying out the method according to the present invention degasses common water containing volatile components that generate gas by heating in a heating container together with dissolved gas, and then General tap water is used as raw water, and 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, and water vapor is generated from this raw water, which is then transferred to the other side of the porous membrane. A pure water production device for obtaining permeated water as pure water by permeating the water and cooling and condensing it on a heat transfer wall, which has an opening for degassing, and
a heating container formed from the hydrophobic polymer porous membrane;
The heat transfer wall is disposed in contact with the heating container wall,
A heat transfer device having a cooling water passage therein.

FIG. 9 shows an embodiment of the apparatus according to FIG. In this device, a cylindrical heating container 33 having an opening 32 is formed from a hydrophobic porous membrane 31, an annular heat transfer device 34 is arranged around the cylindrical heating container 33, and a gap between the heat transfer device and the heating container is provided. A pipe 36 is provided to drain the permeated water from the vapor diffusion space 35.

In the thermopervaporation treatment in the second step, the higher the heating temperature of the raw water, the more permeated water can be obtained, and from the viewpoint of deaeration efficiency, boiling temperature is preferable, but if necessary, it is usually 50°C or higher. temperature. 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.

FIG. 10 shows an apparatus configuration for treating -a clean water with an anion exchange resin as a first step according to the present invention, and then subjecting it to thermopervaporation treatment. supplied to the anion exchange device 37;
Here, as mentioned above, mainly the carbonic acid component is removed, and then heated to the required temperature in the heater 38,
It is supplied to a thermopervaporation device 39.

(Effects of the Invention) As described above, according to the first method of the present invention, in the first step, general tap water is degassed to remove volatile components and dissolved gases, and then the thermopar The vaporization treatment substantially completely removes dissolved substances such as the aforementioned cations and organic substances, and suspended substances such as fine particles and microorganisms. Therefore, according to the method of the present invention, high-quality pure water with an electrical conductivity of 1.0 μS/cm or less can be easily and economically produced through a few steps.

According to the second method of the present invention, in the first step, - the top water is treated with an anion exchange resin; especially,
If only carbon dioxide gas and carbonic acid are removed, then by the subsequent thermopervaporation treatment, in the same manner as above,
High quality pure water can be obtained 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 thermopervaporation processing,
Since high-temperature general water can be treated 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. During treatment, membranes and general water can also be sterilized at high temperatures at the same time. Furthermore, since a hydrophobic membrane is used, there is no clogging of the membrane or concentration polarization, and highly pure water can be efficiently obtained from the top water.

In addition, according to the apparatus of the present invention, the heating container made of a hydrophobic porous membrane serves as a porous membrane body for thermopervaporation treatment as well as a deaerator, so that the apparatus is extremely low in M and tIL. However, it is possible to efficiently produce high-quality pure water.

(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 Mogami water. The properties of this top water are as follows.

Na 10.7 mg/(I
K 2.08mg/lCa
14.2 mg/eMg
3.84mg//! carbon dioxide gas
8.8 ■/1 chlorine ion 16.9
■/l sulfate ion 18.4 ■/l silica 18.2 ■/l total phosphorus
0.05■/β free chlorine 1. O
Less than ppm Ammonia nitrogen 0.5 ppr
Conductivity below n 180 μS/cI11
In the heating container, the above-mentioned Ibaraki city tap water 311 was boiled for 10 minutes to be degassed, and then supplied to the thermopervaporation device at a rate of about 51/min through a pipe.

Thermopervaporation equipment is porous! A flat membrane made of a polytetrafluoroethylene porous membrane lined with a polyamide woven fabric is layered with a 0.5 mm thick polyamide mesh as a spacer, and a heat transfer wall made of a stainless steel plate is provided on the surface of this spacer. It is a flat cell device configured with passages, and the porous membrane has an average pore diameter of 0.
It has micropores of 2 μm, porosity is 80%, and the effective membrane area in the device is 400-.

While cooling water at a temperature of 25° C. was supplied to the cooling water passage of this apparatus at a rate of 51/min, ordinary tap water heated and degassed as described above was supplied to the raw water passage of the apparatus.

Here, the temperature of general tap water in the raw water passage of the device is approximately 9
4°C, and the permeated water as pure water at a temperature of 35°C is about 1
．． It was obtained at a rate of 817 minutes.

Example 2 Pure water was produced in the same manner as in Example 1, except that the heating time for heating and degassing the uppermost water was 30 minutes.

Example 3 In Example 1, - When heating and deaerating the top water,
Except that nitrogen was blown in at the same time at a rate of 1O1Z.
Pure water was produced in the same manner as in Example 1.

In each of the above examples, the tap water after heating and deaeration contained substantially no carbon dioxide (approximately 0.5 ppm
).

Table 1 shows the properties of the pure water obtained in the above examples.

For comparison, pure water produced using a commercially available distiller (Comparative Example 1), pure water produced using an ion exchange device (Comparative Example 2), and pure water produced through preliminary filtration, ion exchange and distillation processes. Table 1 shows the properties of pure water (Comparative Example 3) and pure water obtained by thermopervaporation treatment without degassing (Comparative Example 4).

The pure water obtained by the method of the present invention is
Almost all standards are met. In addition, by comparing this example and Comparative Example 4, it was found that by combining the degassing treatment with the thermopervaporation method, the electrical conductivity was significantly reduced, and the amount of organic substances was also significantly reduced. It is clear that

Example 4 Using the apparatus shown in FIG. 10, the same general tap water as in Example 1 was subjected to anion exchange treatment and then thermopervaporation treatment. The anion exchange device has a resin amount of 50
0m1, and the amount of ordinary tap water flowing through this device at room temperature is 11
/min. The thermopervaporation device used was the same as in Example 1, and the processing conditions were: supply general water temperature 80°C, cooling water temperature 20°C, cooling water supply amount 51°C.
7 minutes, and permeated water at a temperature of 28° C. was obtained at a rate of about 1.517 minutes.

Table 2 shows the type of anion exchange resin used, the exchange capacity (2), the degree of crosslinking, and the properties of the pure water obtained, and Table 3 shows the properties of the pure water obtained by the method of the present invention.

As in Example 1, the pure water obtained by the method of the present invention satisfies almost all pharmacopeia and ASTM standards. It is also clear that by combining the anion exchange treatment with the thermopervaporation process, in particular the electrical conductivity is significantly reduced and the amount of organic substances present is also significantly reduced.

[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 configuration diagram of an apparatus for implementing the first method of the present invention, FIG. 9 is a sectional view showing another apparatus, and FIG. 10 is a configuration diagram of a storage device for implementing the second method of the present invention. shows. 1...Outer tube, 2...Membrane tube, 3...Raw water passage, 9.
...Pipe, 10...Vapor diffusion space, 13...Pure water outlet pipe 4...Spacer, 15...Cooling medium outlet pipe, 21
Heat container, 22...Thermopervaporation 31.
... Hydrophobic polymer porous membrane, 32 ... Opening, ... Heating container, 34 ... Heat exchanger tube, 35 ... Vapor diffusion 37.
... Anion exchange device, 39... Thermopervalation device.

Claims (6)

[Claims] (1) In a method for producing pure water from general tap water, (a
) a first step of degassing common tap water containing volatile components that generate gas when heated together with dissolved gas to remove the volatile components; and (b) a general tap water that has undergone the first step. Water is brought into contact as raw water at a predetermined temperature 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 then transferred to the other side of the porous membrane. A method for producing pure water, comprising a second step of permeating the water, cooling and condensing it to obtain permeated water as pure water. (2) In the first step, the volatile components that generate gas when heated are carbon dioxide gas and carbonic acid that generate carbon dioxide gas when heated, and this is degassed to 5 ppm or less. A method for producing pure water according to claim 1. (3) Deaeration is performed by at least one method selected from aeration, heating deaeration, vacuum deaeration, inert gas blowing, and ultrasonic irradiation. 2. The method for producing pure water according to item 2. (4) In a method for producing pure water from general tap water, (a
) a first step of bringing general tap water containing volatile components that generate gas upon heating into contact with an anion exchange resin to remove the volatile components; and (b) a general tap water that has undergone the first step. Water is brought into contact as raw water at a predetermined temperature 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 then transferred to the other side of the porous membrane. A method for producing pure water, comprising a second step of permeating the water, cooling and condensing it to obtain permeated water as pure water. (5) In the first step, the volatile components that generate gas when heated are carbon dioxide gas and carbonic acid that generate carbon dioxide gas when heated, and this is removed to 5 ppm or less. A method for producing pure water according to claim 4. (6) In a heating container, general public water containing volatile components that generate gas when heated is deaerated together with dissolved gas, and then the degassed general public water is used as raw water and water vapor is allowed to permeate. However, it is brought into contact with one side of a hydrophobic polymer porous membrane that 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 by a heat transfer wall. A pure water production apparatus for condensing and obtaining permeated water as pure water, comprising: a heating container having an opening for deaeration and formed from the hydrophobic polymer porous membrane; and a wall of the heating container. A pure water production apparatus comprising: a heat transfer device having the heat transfer wall disposed in contact with the heat transfer wall and having a cooling water passage therein.