JPH06121902A - Deaerating device and deaerating method - Google Patents

Abstract

PURPOSE:To efficiently deaerate a large quantity of a liquid to be treated by using a deaerating device having a simple structure without a vacuum pump. CONSTITUTION:A passage for cooling a space of the permeating side of a module 3 is formed by a jacket 7 at the outer circumferential part of the casing 2 of the module 3. The liquid to be treated is supplied to the passage. The liquid to be treated flowing out from the jacket 7 is heated to >=80 deg.C by heat exchangers 10, 11 and is supplied to the circular opening of the hollow fiber membrane 1 of the module 3 to permeate the dissolved gas to the outside of the hollow fiber membrane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a degassing apparatus and a degassing method for removing dissolved gas contained in a liquid.

[0002]

2. Description of the Related Art Degassing treatment of liquids is used for producing boiler feed water, feed water for reverse osmosis membranes, pure water, ultrapure water, food grade water, and the like. Further, various deaerators for removing dissolved gas contained in liquid have been proposed. For example, in Japanese Patent Laid-Open No. 2-174902, the pores of the hollow fiber membrane of the module have a temperature of 40 to 80 ° C.
There has been proposed a deaerator for supplying heated water to the module, decompressing the space of the module outside the hollow fiber membrane to 30 to 100 torr with a vacuum pump, and sucking. In addition, Japanese Patent Laid-Open No. 2-16
Japanese Patent Laid-Open No. 0006 discloses that the water to be treated is heated in a heating part and supplied to a container, and the container is evacuated to remove the dissolved oxygen in the liquid to be treated. In addition, an apparatus for separating and removing volatile organic substances by suction is disclosed.

In these apparatuses, the liquid is heated and supplied, and the permeate side of the module is sucked, so that the degassing efficiency can be improved. However, since these devices require a vacuum pump, the maintenance of the device becomes complicated, and when the liquid throughput is increased, the degassing efficiency is not improved so much and the advantage of using a vacuum pump is lost. .

Therefore, an object of the present invention is to eliminate the need for a vacuum pump and to efficiently degas a large amount of liquid to be treated,
An object is to provide a deaerator having a simple structure.

Another object of the present invention is to provide a degassing method capable of efficiently degassing a large amount of liquid to be treated with a simple operation.

[0006]

In order to achieve the above object, the present invention has a module having a polymer membrane permeable to a dissolved gas in a liquid, and one side divided by the polymer membrane. A device for supplying the liquid to be treated to the other side and allowing the dissolved gas to permeate to the other side, and heating means for heating the liquid to be treated supplied to the module, and cooling means for cooling the space on the permeate side of the module. There is provided a deaeration device comprising:

Further, the present invention provides a module having a casing provided with a polymer membrane, and a flow path which is formed on an outer peripheral portion of the casing and cools a space on the permeation side of the module by a liquid to be treated supplied. And a heating means for heating the liquid to be treated flowing out from this flow path, and a supply means for supplying the heated liquid to be treated to the supply side of the polymer film.

Furthermore, the present invention is a method for supplying a liquid to one side of a module partitioned by a polymer membrane and allowing a dissolved gas contained in the liquid to permeate to the other side of the polymer membrane. A degassing method is provided in which a liquid having a temperature of 80 ° C. or higher is supplied to a supply side of a module and the permeate side of the module is cooled.

[0009]

In the degassing apparatus and the degassing method having the above-described structure, since the liquid to be treated supplied to the module partitioned by the polymer membrane is heated, the saturated amount of the dissolved gas contained in the liquid is lowered, The concentration of the dissolved gas can be reduced to the saturated amount at the heating temperature. Therefore, the liquid can be degassed according to the heating temperature of the liquid without using a vacuum pump.

When the polymer membrane is a hydrophobic hollow fiber membrane, not only the contact area with the heated liquid can be increased, but also the selective permeability of the dissolved gas and the degassing efficiency can be further enhanced. The device can be made compact.

[0011]

Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing a deaerator which is an embodiment of the present invention.

This device constitutes a module 3 having a plurality of hollow fiber membranes 1 arranged in the axial direction of a casing 2, a flow path surrounding the outer periphery of the module 3 and supplying a liquid to be treated. And a jacket 7.

Both ends of the casing 2 and both ends of the hollow fiber membrane 1 are sealed with a heat-resistant sealant such as epoxy resin in a state where the end faces of the hollow fiber membrane are open.
Are formed. Also, at both ends of the casing 2,
Supply port 5 for supplying the liquid to be treated to the pores of the hollow fiber membrane 1.
a and an outlet 5b for letting out the treatment liquid from the hollow fiber membrane 1 are formed. Furthermore, in the casing 2,
Exhaust port 6 for letting out gas that has permeated hollow fiber membrane 1
Are formed.

The liquid to be treated supplied from the inlet 8a of the jacket 7 cools the permeate side of the module 3 through the casing 2 and flows out from the outlet 8b. The liquid to be treated flowing out from the jacket 7 is supplied to the first heat exchanger 10 and the second heat exchanger 11 through the supply line 9, is heated sequentially, and is supplied to the supply port 5a of the module 3. As the supply means for supplying the liquid to be treated to the supply port 5a, a water supply pump (not shown) for supplying the liquid to be treated to the inlet 8a of the jacket 7 can be used.

In the first heat exchanger 10, the liquid to be treated is preheated by utilizing the thermal energy of the deaerated liquid. That is, the liquid to be treated heated by the steam in the second heat exchanger 11 is supplied to the supply port 5a of the module 3 and degassed by the hollow fiber membrane 1. The temperature of the liquid flowing out from the outlet 5b of the casing 2 is higher than the temperature of the liquid to be treated supplied to the jacket 7. The liquid having a high temperature is supplied to the first heat exchanger 10 through the processing liquid line 12. Therefore, the liquid to be treated can be preheated in the first heat exchanger 10 by utilizing the thermal energy of the treatment liquid flowing out from the outlet 5b of the module 3, and the liquid not permeating the hollow fiber membrane 1 is It is cooled by the liquid to be treated supplied to 7. Reference numeral 13 is a drain line for discharging the residual liquid in the jacket 7.

In such a deaerator, since the liquid to be treated supplied to the pores of the hollow fiber membrane 1 is heated,
Dissolved gas of a saturated amount or more permeates and is substantially degassed.
Moreover, since the contact area between the plurality of hollow fiber membranes 1 and the liquid to be treated becomes large, the degassing efficiency can be further enhanced.
Therefore, the permeation efficiency of the dissolved gas in the liquid to be treated can be increased without depressurizing the permeate side of the module with the vacuum pump.

Further, in the first heat exchanger 10,
It is possible to transfer heat energy between the liquid that has not passed through the hollow fiber membranes 1 of the module 3 and the liquid to be treated. Therefore, the energy efficiency of the deaerator can be improved.

As the polymer constituting the polymer film, for example, olefin polymers such as high density polyethylene, polypropylene, poly-4-methylpentene-1; polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene. Fluorine-containing polymers such as fluoride, tetrafluoroethylene-ethylene copolymer, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer; silicone resin; polyimide; polyether sulfone; polysulfone; polyphenylene oxide; polyphenylene sulfide; polyarylate; Examples include polyether ether ketone; polyether imide and the like. The polymer can be selected according to the type of liquid to be treated.

When the liquid to be treated is water or an aqueous solution, preferred polymers include hydrophobic polymers such as high density polyethylene, polypropylene, olefinic polymers such as poly-4-methylpentene-1, and fluorine-containing polymers. included.

The polymer membrane may be a homogeneous membrane, a porous membrane, a composite membrane, or the like, but a porous membrane or a composite membrane is preferable because it enhances the permeability of dissolved gas. As the composite film, an active thin film, for example, a film in which a homogeneous layer or a dense layer of a silicone resin is formed on the surface of a porous film is exemplified. As the polymer membrane, a separation membrane having a high selective permeability and a high gas permeation rate is usually selected according to the type of dissolved gas in the liquid.

The form of the polymer membrane is not limited to the hollow fiber membrane, and may be a flat membrane, a spiral wound membrane or the like, but it is a hollow fiber membrane in order to increase the contact area with the liquid to be treated. Is preferred.

Examples of the type of dissolved gas in the liquid include oxygen, nitrogen and carbon dioxide.

In the deaerator of the present invention, the heated liquid to be treated may be supplied to one side divided by the polymer film, depending on the form of the polymer film. The heating means for heating the liquid to be treated is not limited to steam and may be any conventional heating means such as a heater, a flame, a heat medium, or electromagnetic induction heating. The heating temperature of the liquid to be treated by the heating means is 80 ° C. or higher, preferably 80 to 125.
C., more preferably about 85 to 100.degree. In addition, in the embodiment shown in FIG. 1, the first heat exchanger is not always necessary.

The cooling means for cooling the space on the permeate side of the module is not limited to the liquid to be treated as shown in FIG. 1, but various refrigerants can be used.

Further, in the device of the present invention, a plurality of modules may be connected in series or in parallel.

In the apparatus shown in FIG. 1, the liquid to be treated supplied to the jacket is used for cooling the permeate side of the module, and the liquid treated in the module is used for preheating the liquid to be treated. The means and the heating means may be provided separately.

In the degassing method of the present invention, one side of the module partitioned by the polymer membrane has a temperature of 80 ° C. or higher,
Preferably 80-125 ° C, more preferably 85-1
A liquid of about 00 ° C. is supplied, the dissolved gas contained in the liquid is permeated to the other side of the polymer membrane, and the permeate side of the module is cooled. When heated to a temperature of 80 ° C. or higher, not only the residual concentration of the dissolved gas in the liquid to be treated is significantly lowered, but also the permeability of the polymer membrane can be increased without using a pressure reducing means such as a vacuum pump.

The liquid to be treated may be heated without being heated by a heat exchanger or the like, before being supplied to the module, by storing the liquid to be treated in a tank and opening it. In this case, the dissolved gas concentration in the heated liquid can be reduced and supplied to the module, and the degassing efficiency of the dissolved gas can be increased.

The degassing apparatus and degassing method of the present invention can be applied to various liquids such as water, tap water, industrial water, eluents for liquid chromatography, samples, food water, chemical water, boiler feed water, reverse osmosis. It is useful for producing membrane feed water, pure water, organic solvents, etc. In particular, it is useful in applications where a large amount of treatment is required and in which it is not necessary to reduce the dissolved gas concentration so much, for example, production of water for water heaters, water for foods, and the like.

[0031]

The deaerator of the present invention does not require a vacuum pump, can efficiently deaerate a large amount of liquid to be treated, and has a simple structure.

According to the degassing method of the present invention, a large amount of liquid to be processed can be efficiently degassed by a simple operation.

[0033]

[Experimental Example] The present invention will be described in more detail based on an experimental example.

As a polymer film, a hollow fiber polypropylene porous film (manufactured by Daicel Chemical Industries, Ltd., Celgard X)
-10, inner diameter 0.24 mm, outer diameter 0.30 mm) was used to fabricate a module having an inner surface standard film area of 33 m ² .

This module was installed in the line shown in FIG. 1, and the water of Osaka city was used as raw water, and the temperature at the module inlet was 80%.
Water was passed through the module under conditions of a temperature of ℃ and a flow rate of 1000 L / hr at the module inlet. The dissolved oxygen concentration of raw water was 8.1 ppm at 25 ° C.

Then, after the treated water at the module outlet was cooled by a heat exchanger and the dissolved oxygen concentration was measured, it was found to be 25
It was 3.0 ppm at ° C.

In a similar manner, the module inlet temperature was adjusted to 9
When it was set to 0 ° C., the dissolved oxygen concentration of the treated water at the module outlet was 2.0 ppm at 25 ° C.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a deaerator which is an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hollow fiber membrane 2 ... Casing 3 ... Module 7 ... Jacket 10, 11 ... Heat exchanger

Claims (4)

[Claims] 1. A module having a polymer membrane permeable to a dissolved gas in a liquid, the liquid to be treated is supplied to one side divided by the polymer membrane, and the dissolved gas is supplied to the other side. A degassing device, which is a device for permeation, comprising heating means for heating the liquid to be treated supplied to the module and cooling means for cooling the space on the permeation side of the module. 2. A module having a casing provided with a polymer membrane, a flow path formed on an outer peripheral portion of the casing and for cooling a space on the permeation side of the module by a liquid to be treated supplied, and this flow path. A deaerator comprising: heating means for heating the liquid to be treated flowing out from the passage; and supply means for supplying the heated liquid to be treated to the supply side of the polymer film. 3. The degassing device according to claim 1, wherein the polymer membrane is a hydrophobic hollow fiber membrane. 4. A liquid is supplied to one side of the module partitioned by the polymer membrane, and the other side of the polymer membrane is supplied with the liquid.
A method for permeating a dissolved gas contained in a liquid, comprising:
A degassing method in which a liquid at 0 ° C. or higher is supplied to the supply side of the module and the permeate side of the module is cooled.