JPH01218681A - Pure water generator - Google Patents

Abstract

PURPOSE:To produce pure water containing a small amount of oxygen efficiently, by providing a deaerator for removal of gases in raw water in a raw water feed line in a pure water generator by thermo pervaporation process. CONSTITUTION:Raw feed water (a) is fed to a deaerator 3 to be deaereted and cooled thereby and cools thereafter a steam chamber 1B through a heat transfer surface for cooling 5 and is heated at a beater 6 to be thereafter supplied to a liquid chamber 1A. As a result, a temperature difference is produced between the liquid chamber 1A and the steam chamber 1B, whereby a difference in partial pressure corresponding to said temperature difference causes the steam to be passed through a permeable membrane 4 from the liquid chamber 1A toward the steam chamber 1B so that the steam is condensed into pure water by cooing action of the heat transfer surface 5, while concentrated water (b) of high temperature is used as raw water (a). On the other hand, by the cooling effect caused by deaeretion at the deaerator 3, the raw water (a) having become high temperature by using the concentrated water (b) as raw water (a) can be cooled to a predetermined temperature, leading to an energy saving.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a porous or non-porous material that selectively transmits only water vapor from a high temperature side to a low temperature side with a water vapor partial pressure difference corresponding to the temperature difference between the two sides. A device that produces pure water using a permeable membrane. Specifically, it is equipped with a separator that is internally partitioned into a liquid chamber and a vapor chamber, and a water supply channel for supplying raw water to the liquid chamber of the separator. , a cooling means for cooling the vapor chamber to a temperature lower than that of the liquid chamber is provided, and the permeable membrane is provided as a partition between the liquid chamber and the vapor chamber in the separator, using a so-called thermopervaporation method. Regarding pure water production equipment.

[Conventional technology]

As shown in Figure 6, in a conventional pure water production device of this type, the interior of the separator (1) is divided into three parts: a liquid chamber (1A) in the center and steam chambers (1B) on both sides. , each of these partitions may be composed of the above-mentioned permeable membranes (4) (for example, Japanese Patent Publication No. 49-45461@), or as shown in FIG. (4) installed,
Liquid (1A) is passed between the separator (1) and the cylindrical permeable membrane (4).
In addition, a device in which a steam chamber (1B) is formed inside the cylindrical permeable membrane (4) is conventionally known (for example, Japanese Patent Laid-Open No. 118204/1983). In addition, (5) is the steam room (1B)
It is a heat transfer surface that cools the inside.

・12 Problems to be Solved by the Invention] However, when using the above-mentioned conventional devices, in each case, attempts were made to increase the amount of vapor permeation by increasing the area of the permeable membrane, but the amount of vapor permeation was increased. No attention was paid to the gases in the raw water.

However, in pure water production equipment, it is customary to make the pressure in the liquid chamber slightly higher than the pressure in the steam chamber, so the gas in the raw water and the steam are used as driving force by the pressure difference between the liquid chamber and the steam chamber. The liquid passes through the permeable membrane from the liquid chamber toward the vapor chamber.

Such intrusion of gas in the raw water into the steam chamber causes the following inconveniences.

That is, firstly, by adhering to the gas permeable membrane on the liquid chamber side, the permeation of water vapor through the permeable membrane is hindered, and the amount of water vapor permeated is reduced. However, increasing the differential pressure between the liquid chamber and the steam chamber to ensure the amount of water vapor permeation increases pressurization energy, which is not preferable from an energy saving perspective.

Second, in this type of pure water production equipment, since it is a thermoparation type, it is not possible to increase the distance between the heat transfer surface of the cooling means that cools the steam chamber and the surface of the permeable membrane. Therefore, it is difficult to smoothly discharge the gas that has entered between the heat transfer surface and the permeable membrane, that is, into the steam chamber, and the gas tends to accumulate so as to cover the heat transfer surface. Cooling of water vapor is inhibited.

Thirdly, since the pure water produced by condensing water vapor during cooling on the heat transfer surface contains gas, that is, oxygen, the pure water becomes susceptible to the growth of bacteria. .

An object of the present invention is to provide a pure water production apparatus that can efficiently produce pure water with a low oxygen content by eliminating the above-mentioned disadvantages caused by gases contained in raw water.

[Means to solve the problem]

A feature of the pure water production apparatus according to the present invention is that the water supply channel is provided with a deaeration device for removing gas from the raw water to be supplied, and its functions and effects are as follows.

[For production]

In other words, since raw water with a low gas content is supplied into the liquid chamber, the first step is to suppress the gas from inhibiting water vapor from permeating through the permeable membrane from the liquid chamber side to the vapor side. The amount of water vapor that permeates can be increased without particularly increasing the differential pressure between the liquid chamber and the steam chamber, and secondly, the amount of gas that naturally passes through the permeable membrane and enters the steam chamber is reduced, which reduces the cooling means. The water vapor can be efficiently cooled by the heat transfer surface, and thirdly, the oxygen content of the produced pure water can be reduced.

〔Effect of the invention〕

As a result, the present invention has made it possible to efficiently produce pure water that has a low oxygen content and is highly effective in inhibiting bacterial growth, while saving energy and at low cost.

〔Example〕

Next, examples of the present invention will be shown.

As shown in FIG. 1, the pure water production apparatus includes a separator (1), a water supply channel (2), a cooling means, and a deaerator (3).

The separator (1) is internally partitioned into a liquid chamber (1A) and a steam chamber (1B), and the partition (1a) is divided from the high temperature side to the low temperature side with a water vapor partial pressure difference corresponding to the temperature difference between the two sides. A porous permeable membrane (4) that selectively allows only water vapor to pass through the
) is formed from.

The water supply channel (2) is connected to the liquid chamber (1A) of the separator (1).
The separator (1) supplies raw water (a) to the separator (1).
) and a cooling passage (2A) formed adjacent to the steam chamber (1B), and a cooling passage (2A) formed with raw water (
a) and a supply pipe (2B) that supplies the cooling passage (
2A) to the liquid chamber (1A) (through the intermediate pipe (2C) and the concentrated water (b) concentrated by evaporation in the liquid chamber (1A) as the raw water (a). Supply piping (2B
) and new water such as tap water (2D).
c) as raw water (a) and a new water supply path (2E) that supplies the water to the supply pipe (2B). In other words, in this water supply channel (2), mixed water of concentrated water (b) and new water (c) is supplied to the separator (1) as raw water (a), and the raw water for new water (c) is supplied to the separator (1) as raw water (a). The usage amount (Q2) as (a) is the required supply amount of raw water (a), Q,? 1. If the amount of condensed water (b) is Ql, the basic formula is Q, =Q-Q. In other words, new water (c) is supplied in a form to compensate for the amount lost when the raw water (a) becomes concentrated water (b) through concentration (evaporation) in the separator (1). To give a specific example,
Usually, the ratio is 95 parts concentrated water (b) to 5 parts fresh water (c).

The cooling means cools the inside of the vapor chamber (1B) into the liquid chamber (1A) so that water vapor permeates the porous permeable membrane (4) from the liquid chamber (1A) side toward the vapor chamber (1B) side. A means for condensing water vapor in the steam chamber (1B) by cooling it to a lower temperature than , forming a cooling heat transfer surface (5) for cooling the inside of the steam chamber (1B) with the supplied raw water (a), and forming an intermediate pipe (2) of the water supply channel (2).
A heater (6) for heating the supplied raw water (a) is interposed in the water supply system C). The heater (6) has a heating fluid (d
) The raw water (a) is heated by heat exchange with the water (a).

The deaerator (3) includes a supply pipe (
2B) to remove gas in the feed raw water (a), specifically, a deaerator (3A) installed in the supply pipe (2B) and a cooling water ( an ejector (3B) that reduces the pressure inside the deaerator (3A) by suctioning gas from the deaerator (38) with the ejection of c); and a condenser that condenses water vapor in the suction gas. capacitor (3
C). Therefore, according to this deaerator (3), in addition to deaeration, the raw water (a) is cooled.

In addition, (7) in the figure is the condensed water, that is, pure water extraction path connected to the steam room (1B), and (8) is the drain pipe that discharges a part of the concentrated water as blow water. be.

Therefore, according to the above configuration, the feed raw water (a) reaches the deaerator (3), is deaerated and cooled by the deaerator (3), and then passes through the cooling heat transfer surface (5). Steam room (1B) through
is cooled and heated by the heater (6), and then transferred to the liquid chamber (18).
is supplied to As a result, the liquid chamber (1A) and the vapor chamber (1B
), water vapor passes through the permeable membrane (4) from the liquid chamber (1A) side toward the vapor chamber (1B) side with a water vapor partial pressure difference corresponding to the temperature difference, and is cooled. The cooling effect of the heat transfer surface (5) causes condensation and pure water is produced.

While the high temperature concentrated water (b) is used as raw water (a), the concentrated water (b) is used as raw water (a) due to the cooling effect accompanying degassing in the deaerator (3). Since the raw water (a), which has become high in temperature, is cooled down to a predetermined temperature, energy saving can be achieved.

In other words, in order to efficiently produce pure water, the liquid chamber (
It is necessary to ensure a sufficient temperature difference between 1A) and the steam room (1B), but if the temperature of raw water (a) is lowered unnecessarily,
The load on the heater (6) becomes large and a large amount of heating energy is required.

As a result, from the viewpoint of pure water production efficiency and energy saving, the raw water (raw water) supplied to the separator (1) as cooling water (
The temperature in a) may vary depending on the design, but it may be around 40°, and in such cases, new water such as tap water (
When only c) is supplied as raw water (a), it is necessary to heat the new water (c). However, in the above embodiment, since the concentrated water (b) is used as the raw water (a), there is no need to heat the raw water (a) before supplying it to the separator (1), resulting in energy savings. It can be achieved.

Moreover, since the concentrated water (b) whose temperature stabilizes when it is in a steady state of operation occupies most of the raw water (a), the temperature at the inlet of the deaerator (3) remains constant regardless of the mixing of fresh water (c). While the temperature change of the raw water (a) is small and the deaerator (3) can be operated easily, variations in the temperature of the raw water (a) at the inlet of the separator (1) are suppressed and the liquid chamber (1A ) and steam room (1
By stably maintaining the temperature difference with B), steam generation can be performed stably.

Next, an experiment conducted by the present inventor will be described.

Experimental Example 1 As shown in Fig. 2, the experiment was conducted using a thermopervaporation membrane module as the separator (1), with a structure in which concentrated water (b) is not returned to raw water (a), and only tap water is converted into raw water ( a)
The pure water production apparatus was operated under the conditions shown in Table 1, and the following items were examined: pure water temperature, concentrated water temperature, pure water production volume, and pure water type conductivity. The results are shown in Table 2. In addition,
The specifications of the thermopervaporation membrane module are shown in Table 3.

Experimental Example 2 As shown in FIG. 3, the experiment was carried out using a pure water production apparatus according to the present invention, which was the same as the apparatus of Experimental Example 1, but added a vacuum degassing device (3) using a vacuum pump (P), as shown in Table 1. The test was conducted by operating the vehicle under the conditions shown and examining each of the items mentioned above. The results are shown in Table 2. Note that the degree of vacuum of the vacuum deaerator (3) is 22 TORR.

Experimental Example 3 As shown in Fig. 4, an experiment was conducted in which the apparatus of Experimental Example 1 was modified to return concentrated water (b) to raw water (a), and was operated under the conditions shown in Table 1. This was done by examining each item. The results are shown in Table 2.

Experimental Example 4 As shown in Fig. 5, the experiment was conducted using the apparatus of Experimental Example 3 using pure water according to the present invention, which was equipped with a vacuum deaerator (3) comprising a vacuum pump (P) and a cooler (10). Table 1 shows the manufacturing equipment.
The tests were carried out by operating the vehicle under the conditions shown below and examining each of the items mentioned above. The results are shown in Table 2.

Table 1 Table 2 2-2.4 1.82 Table 3 As is clear from the above experiments, it was found that the amount of pure water produced could be increased by degassing the raw water.

[Another example]

Another example of the present invention will be shown below.

[1] In the above embodiment, the deaerator (3) cools and deaerates the supplied raw water (a) by suction by the ejector (3B) and cooling by the condenser (3C).
The degassing device (3) may be one that performs deaeration using a vacuum pump, or one that uses a water jet ejector condenser that serves both steam condensation and vacuum evacuation.

[2] In the above embodiment, the heater (6) is one that heats the raw water by heat exchange with the heating fluid (b), but the heater (6) may be a heater, a burner, etc. Also good.

[3] The structure and shape of the separator (1) can be changed as appropriate.

[4] In the above embodiment, the partition (1a) was entirely composed of the permeable membrane (4), but the permeable membrane (4)
) may be provided partially.

[5] In the above embodiments, the permeable membrane (4) is porous, but the permeable membrane (4) may be non-porous.

[6] Note that although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, and FIGS. 2 to 5 are schematic configuration diagrams of an experimental apparatus. FIG. 6 and FIG. 7 are configuration diagrams showing a conventional example. (18)...Liquid chamber, (1B)...Steam chamber, (1)...Separator, (2)...... Water supply channel, ( 1a)...Partition, (3)...
- Deaerator, (4)... Permeable membrane.

Claims (1)

[Claims] A separator (1) whose interior is partitioned into a liquid chamber (1A) and a steam chamber (1B) is provided, and a water supply channel is provided for supplying raw water (a) to the liquid chamber (1A) of the separator (1). (2) and a cooling means for cooling the inside of the vapor chamber (1B) to a lower temperature than the inside of the liquid chamber (1A), the liquid chamber (1A) of the separator (1)
Pure water is provided in the partition (1a) between the and steam chamber (1B) with a permeable membrane (4) that selectively transmits only water vapor from the high temperature side to the low temperature side with a water vapor partial pressure difference corresponding to the temperature difference on both sides. A pure water manufacturing apparatus, wherein the water supply channel (2) is provided with a deaerator (3) for removing gas from the raw water to be supplied.