JP2005218955A - Gas-liquid contact device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To install a swirling flow generating device for forming a swirling flow of a gas-liquid mixed fluid mixed with gas in the liquid, generate ultra fine bubbles in the liquid installed using the swirling flow, and dissolve Providing a gas-liquid contact device that suitably performs oxygen enrichment or removal of volatile organic compounds.
SOLUTION: A gas-liquid mixed fluid inlet in a tangential direction of a cylindrical portion of a cylindrical swirling flow generating container having end plates at both ends, a gas-liquid mixed fluid ejection opening in a central portion of a lower end plate, The front ejection opening has the narrowest center part of the end plate in the moving direction of the gas-liquid mixed fluid, the inflow side and the outflow side are wide, and the cross-sectional shape of the opening in the moving direction of the gas-liquid mixed fluid is from the narrowest part to the inner side And a pump that circulates the liquid to the fluid inlet via a circulation pipe, and a suction side of the pump, in which a swirl flow generator that has a curved line continuously expanding toward the outside is installed in the liquid Gas-liquid contact is performed using a gas-liquid contact device provided with a gas suction tube for sucking gas.
[Selection] Figure 1

Description

According to the present invention, a swirl flow generating device that forms a swirl flow of a gas-liquid mixed fluid is installed in the liquid, and the gas-liquid contact can be efficiently performed in the liquid installed using the swirl flow. The present invention relates to a gas-liquid contact device.
More specifically, a swirling flow generating device that forms a swirling flow of a gas-liquid mixed fluid mixed with gas is installed in the liquid, and the liquid is clouded in the liquid that is installed using the swirling flow. It is possible to suitably perform generation of ultrafine bubbles, enrichment of dissolved oxygen, purification of sewage by promoting air oxidation, dissolution of ozone, removal of residual chlorine, deoxygenation in water or removal of volatile organic compounds (VOC), etc. The present invention relates to a gas-liquid contact device.

[Prior art documents]
Japanese Patent Laid-Open No. 10-230150 JP, 2003-275557, A As a method of purifying the water of rivers and lakes or the purification of sewage such as domestic wastewater, it has been practiced to use the biooxidation action by aerobic microorganisms in the liquid to be treated for a long time. In order to activate the microorganisms, air fine bubbles have been sent into the liquid to be treated. In addition, for the microbubble generator for that purpose, various structures such as a diffuser tube having a pore, a perforated plate, or a rotary blade have been used.

In the device that generates bubbles using the above-described diffuser tube or perforated plate, the gas passes through the pores and is supplied to the liquid, but the pores gradually narrow as it is used, and finally clogging occurs. There is a variation in bubble size or a decrease in bubble generation rate, the supply of bubbles becomes unstable, and the amount of bubble generation is limited.
Furthermore, although the stirring action is inadequate and effective for a limited volume of processing liquid, large volume liquid processing such as lakes is impossible.

In addition, the bubble generation device by a mechanical method using a stirring blade, etc., generates gas bubbles by subdividing the gas introduced by the rotating blades into gas-liquid contact, which consumes a large amount of energy and has a bubble size. There is a drawback of large variations.
In this way, the present inventors have proposed a gas-liquid contactor called an aerator that forms a swirling flow of liquid, sucks gas using the negative pressure generated by the swirling flow, and generates bubbles. (See Patent Document 1).

  This gas-liquid contactor swirls along the wall of the swirl flow generating container by allowing liquid to flow into the cylindrical swirl flow generating container having end plates at both ends from the tangential direction of the cylindrical portion. However, a liquid flow toward the fluid ejection opening that is ejected into the liquid is formed (this is referred to as a swirling flow in this specification), and the swirling flow generates a negative pressure in the container to suck the gas. There is a gas-liquid contact by generating bubbles by blowing the sucked gas into the liquid from the opening formed on the end plate on the side opposite to the end plate on the suction side of the swirl flow generating container. It is.

In this aerator, the driving force for sucking the gas is a flowing liquid, and the gas is conveyed by the suction force of the flowing liquid. Therefore, there is no need for a driving device for this aerator. Since only the container and the pipe are provided, the structure can be simplified and reduced in size.
Further, the generated bubbles are fine and uniform, and when they are generated in large quantities and used for water purification, the purification performance can be remarkably improved.
The present inventors have continued research on the gas-liquid contactor to further improve the characteristics thereof, and as a result, the shape of the fluid ejection opening shown in FIG. 5 is adopted. As a result, it has been found that energy efficiency and bubble generation efficiency are improved, and a patent application has already been filed for this (see Patent Document 2).

The shape of the fluid ejection opening will be described in detail as follows.
In Patent Document 2, it has been proposed that the energy efficiency and bubble generation efficiency can be improved by narrowing the central portion in the fluid movement direction with respect to the fluid ejection opening and widening the inflow side and the outflow side.
The gas-liquid contactor that has been developed by the present inventors and makes gas-liquid contact by sucking gas using the negative pressure generated by the swirling flow of liquid has excellent characteristics as described above. Also, the amount of gas sucked by the swirl flow is large, and as a result, the gas is not sufficiently refined.

Therefore, the present inventors have made intensive research and development to develop a gas-liquid contact device that can perform gas-liquid contact with higher efficiency while taking advantage of the gas-liquid contact utilizing this swirl flow. The present invention has succeeded in developing the results.
Therefore, it is an object of the present invention to provide a gas-liquid contact device using a swirl flow of liquid that can sufficiently miniaturize gas.
That is, an object of the present invention is to provide a gas-liquid contact device that has high gas dissolution efficiency and can efficiently make gas-liquid contact.

The present invention provides a gas-liquid contact device using a fluid swirl flow that solves the above-mentioned problems, and the gas-liquid contact device includes a cylindrical swirl flow generating container having end plates at both ends, A gas-liquid mixed fluid inlet provided in a tangential direction of the cylindrical portion, and a gas-liquid mixed fluid jet opening provided in a central portion of the lower end plate, the fluid jet opening of the gas-liquid mixed fluid The central portion of the end plate in the moving direction is the narrowest, the inflow side and the outflow side are wide, and the cross-sectional shape of the opening in the gas-liquid mixed fluid moving direction is from the narrowest portion toward the inner side and the outer side. A swirling flow generating device having a continuously expanding curve is installed in the liquid, and a gas that circulates the liquid to the fluid inlet through a circulation pipe and a gas that sucks gas to the suction side of the pump The suction pipe is installed.

In the gas-liquid contact device of the present invention, the gas is not sucked using the negative pressure generated by the swirling flow of the liquid, but is sucked on the suction side of the pump and moves with the liquid to the discharge side. It is supplied into the swirl flow generator in a liquid mixed state and is ejected from the fluid ejection opening.
As a result, in the present invention, after the gas is discharged from the fluid ejection opening of the swirling flow generating device, the gas becomes so fine that the liquid existing in the water tank becomes clouded.
Further, since the gas is sucked on the suction side of the pump, there is an upper limit for normal operation of the pump, which is usually 6 vol% or less of the liquid passing through the pump.
As described above, the amount of sucked gas is very small, but the total surface area of the generated bubbles is extremely large.
As a result, in the present invention, the gas-liquid contact can be efficiently performed with high gas dissolution efficiency.

In the present invention, the gas-liquid mixed fluid ejected into the liquid in which the swirl flow generator is installed has a special shape at the fluid ejection opening, resulting in a shallow water depth and a short movement distance in the horizontal direction. Therefore, even when a swirl flow generator is installed in a container to enrich dissolved oxygen, remove VOC, etc., a large-capacity container having a large capacity and a deep water depth is not required.
In addition, since the fluid ejected from the fluid ejection opening is evenly dispersed in the horizontal direction, and the liquid level does not fluctuate, the gas dissolution efficiency is high even in this respect, and the gas-liquid contact is efficiently performed. It can be carried out.

For example, the liquid level does not fluctuate as compared with the case where a nozzle is used as an opening for ejecting fluid into the liquid.
Further, in the case of using the gas-liquid contact device of the present invention, the case of using the gas-liquid contactor proposed in Patent Document 2, that is, the gas is sucked by generating a negative pressure in the swirling flow generating container by the swirling flow. Compared with the case of contact, oxygen in water can be deaerated with a small amount of nitrogen gas.
Furthermore, when oxygen is dissolved by aeration, both the case of using the gas-liquid contactor proposed in Patent Document 2 and the case of using the gas-liquid contactor of the present invention reach a state close to the saturated concentration in the same amount of time. However, in the case of using the gas-liquid contact device of the present invention, it can be dissolved at a saturation concentration or higher (about 130%), whereas in the case of using the gas-liquid contactor, it takes time to completely saturate. It is impossible to dissolve more than that.

Hereinafter, embodiments of the present invention including the best mode for carrying out the invention will be described in detail with reference to the drawings. However, the present invention is not limited thereto, and the scope of the claims is described below. Needless to say, it is specified by.
FIG. 1 illustrates a gas-liquid contact device 10 according to the present invention, and the gas-liquid contact device 10 includes a swirling flow generator 1 disposed in water.
In the illustrated gas-liquid contact device 10, the swirling flow generating device 1 is installed in the water stored in the water tank 11, and the water in the water tank is taken out and the gas-liquid mixed fluid of the swirling flow generating device 1 is shown. A circulation pipe 14 to be supplied to the inflow pipe 5, a pump 12 installed in the middle of the circulation pipe, and a gas suction pipe 13 installed on the suction side of the pump are provided.

An example of the swirling flow generating device 1 included in the gas-liquid contact device 10 is shown in FIG. 2, and a cylindrical swirling flow generating container having end plates at both ends and the tangent line of the cylindrical portion 2. It has a gas-liquid mixed fluid inflow pipe 5 provided in the direction and a gas-liquid mixed fluid ejection opening 8 provided in the center of the lower end plate 4.
The fluid ejection opening 8 has the narrowest central portion 8a of the end plate in the moving direction of the gas-liquid mixed fluid, the inflow side 8b and the outflow side 8c being wide, and a cross section of the opening in the direction of moving the gas-liquid mixed fluid. The shape is a continuous curve expanding from the narrowest portion toward the inner side and the outer side.

Based on the illustrated gas-liquid contact device 10 of the present invention, the operation of the dissolved oxygen enrichment process will be described as follows.
The water in the water tank 11 is sucked by the pump 12 and supplied to the gas-liquid mixed fluid inlet 6 from the gas-liquid mixed fluid inlet pipe 5 of the swirling flow generating device 1 through the circulation pipe 14. Then, a swirl flow is formed and flows down, and is ejected from the gas-liquid mixed fluid ejection opening 8 into the water in the water tank.
At that time, in the pump 12, air is sucked from the gas suction pipe 13 installed on the suction side, and the swirling flow generating device 1 is supplied with the gas-liquid mixed fluid mixed with air, The gas suction pipe 7 must be installed on the suction side, not on the discharge side of the pump.

In the present invention, the air jetted into the liquid in the water tank 11 from the gas-liquid mixed fluid jet opening 8 in this way is extremely refined, and the liquid in the water tank becomes clouded.
This white turbid liquid is repeatedly circulated and supplied to the swirl flow generator 1 and repeatedly subjected to gas-liquid contact. As a result, not only water saturated with oxygen is formed, but also water that has become supersaturated. Can also be formed.
Regarding the gas-liquid mixed fluid ejection opening 8 formed in the lower end plate 4 of the swirling flow generating device 1 used in the illustrated gas-liquid contact device 10 of the present invention, the end plate in the moving direction of the gas-liquid mixed fluid The central portion 8a is the narrowest, the inflow side 8b and the outflow side 8c are widened, and the cross-sectional shape of the opening in the gas-liquid mixed fluid moving direction expands from the narrowest portion toward the inner side and the outer side. As long as it is a continuous curve, it can be used without any particular limitation.

In this regard, FIG. 2 shows a typical structure. According to the figure, the narrowest part exists in a direction perpendicular to the direction of fluid movement, and exists in a thin line shape in an annular shape. Instead of a simple shape, it may be a shape that exists in a wide band shape as shown in FIG.
As for the structure of the lower end plate of the swirling flow generating device, the inner surface of the swirling flow generating container may be an inclined surface that descends from the cylindrical wall of the container toward the fluid ejection opening as shown in FIG. By doing in this way, the solid which flowed in the swirl | vortex flow generator can be discharged | emitted smoothly.

As the swirl flow generator, the same structure as the gas-liquid contactor proposed in Patent Document 2 shown in FIG. 5 can be used, and in that case, the swirl generator is installed at the center of the upper end plate 3. The suction pipe 15 used for gas suction is used for liquid suction.
That is, the suction pipe 15 sucks the liquid in the water tank 11 instead of the gas suction to the liquid suction, and becomes a part of the gas-liquid mixed fluid from the gas-liquid mixed fluid ejection opening provided in the lower end plate 4. The liquid in the water tank in which the swirling flow generator is installed can be circulated and agitated in an auxiliary manner, and the sound generated by driving the swirling flow generator can be greatly reduced.
In this case, it is necessary to make the tip opening located outside the swirl flow generator of the suction pipe submerged in water.

In addition, the gas-liquid mixed fluid inlet provided in the tangential direction of the cylindrical portion of the cylindrical swirl flow generation container can be attached to the swirl flow generation container in a direction (horizontal direction) orthogonal to the cylindrical portion. Of course, it can also be attached in a direction inclined downward as shown in FIG.
Furthermore, as for the pump for sucking the gas, various pumps can be used without particular limitation as long as the pump has a capacity of about 20 m or more, and examples thereof include a vortex pump, a vortex pump, or a submersible pump. it can.

As described above, the gas-liquid contact apparatus of the present invention is suitable for enriching dissolved oxygen, purifying sewage by promoting air oxidation, dissolving ozone gas, removing residual chlorine, deoxygenating water, removing volatile organic compounds (VOC), and the like. As described above, for the enrichment of dissolved oxygen, when the water to be treated is circulated and supplied to the swirl flow generator, it is introduced into the water by being sucked into the suction side of the pump and dissolved. It increases oxygen. The water to be treated at that time may of course be water in a water tank, but may also be pond water.
Furthermore, sewage purification by promoting air oxidation can also be performed by introducing air into the water to be treated, such as wastewater or sewage, as in the case of enrichment of dissolved oxygen, and ozone gas can be dissolved similarly. This can be done by introducing ozone gas into the gas.

For deoxygenation in water, supply oxygen-free gas such as nitrogen gas or carbon dioxide gas instead of air to the suction side of the pump, suck it, and supply it to the swirl flow generator as before And introduced into the water to be treated.
As a result, most of the introduced oxygen-free gas is volatilized from the water to be treated, and oxygen is also volatilized at that time, so that oxygen can be separated from the water and the water to be treated is deoxygenated. it can.

Furthermore, the removal of residual chlorine or VOC can be performed in the same manner as in the case of deoxygenation in water.
The suction gas used at that time can be used without particular limitation as long as it is a water-insoluble gas other than chlorine or VOC, but is easily available and inexpensive, such as air, nitrogen gas or carbon dioxide gas. Etc. are good.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples, and is specified by the description of the scope of claims. Needless to say.
Using the gas-liquid contact device 10 of the present invention shown in FIG. 1, 1 m ³ (same concentration 0.6 mg / L) of water stored in the water tank 11 from which most of the dissolved oxygen has been removed in advance. In addition, the air sucked from the gas suction tube 13 was supplied, an oxygen dissolution test was performed, and the change over time in the dissolved oxygen concentration was measured.

At that time, the swirling flow generator 1 was rated at a 200 mm inner diameter and the pump 12 was rated using a centrifugal pump rated at 3.7 kW.
As a comparative example, instead of the swirling flow generating device 1, air is sucked from the suction pipe 15 using the gas-liquid contactor proposed in Patent Document 2 shown in FIG. Inhalation was conducted and an oxygen dissolution test was conducted in the same manner as in Example 1, and the change over time in the dissolved oxygen concentration was measured.
At that time, the gas-liquid contactor was installed in the water tank 11 so that the upper end of the pipe would not be submerged so that air could be sucked from the suction pipe.

The results of these dissolution tests are as shown in FIG.
According to this, it can be seen that both the case of the present invention and the case of the comparative example, the dissolved oxygen reaches a state close to the saturated concentration in an elapsed time of about 10 minutes.
However, in the case of using the gas-liquid contact device of the present invention, it can be dissolved at a saturation concentration or higher (about 130%), whereas in the case of using the gas-liquid contactor proposed in Patent Document 2 of the comparative example, It can be seen that it takes about 30 minutes to saturate and it is impossible to dissolve it further.

Further, the removal of the dissolved oxygen is performed by sucking nitrogen gas instead of air from the gas suction pipe 13 by using the gas-liquid contact device 10 shown in FIG. It was possible to reduce.
On the other hand, when the gas-liquid contactor proposed in Patent Document 2 is used instead of the swirl flow generator as in the comparative example and nitrogen gas is sucked from the suction pipe 15, dissolved oxygen is as in the case of the present invention. It was not possible to reduce the amount to 0.6 mg / L, and the amount of nitrogen gas used was enormous compared to the case of the present invention.

The gas-liquid contact apparatus of this invention is illustrated. An example of the swirl | vortex flow generator used for the gas-liquid contact apparatus of this invention is illustrated. The example of the other aspect of the swirl | vortex flow generator used for the gas-liquid contact apparatus of this invention is illustrated. The example of the further another aspect of the swirl | vortex flow generator used for the gas-liquid contact apparatus of this invention is illustrated. The gas-liquid contactor proposed by patent document 2 is illustrated. The result of the dissolution test of Example 1 of this invention is illustrated.

Explanation of number

DESCRIPTION OF SYMBOLS 1 Swirling flow generator 2 Cylindrical part 3 Upper end plate 4 Lower end plate 5 Gas-liquid mixed fluid inflow pipe 6 Gas-liquid mixed fluid inflow port 8 Fluid ejection opening 8a Center part of the opening 8b Inlet side of the opening 8c The Outlet side of opening 10 Gas-liquid contact device 11 Water tank 12 Pump 13 Gas suction pipe 14 Circulation pipe 15 Suction pipe

Claims (5)

Cylindrical swirl flow generating container having end plates at both ends, a gas-liquid mixed fluid inlet provided in the tangential direction of the cylindrical portion, and a gas-liquid mixed fluid jet provided in the center of the lower end plate The fluid ejection opening has a narrowest central portion of the end plate in the moving direction of the gas-liquid mixed fluid, the inflow side and the outflow side are widened, and the opening in the moving direction of the gas-liquid mixed fluid A swirl flow generator having a cross-sectional shape that curves continuously from the narrowest portion toward the inner side and the outer side is installed in the liquid, and the liquid is introduced into the fluid inlet through a circulation pipe. A gas-liquid contact device using fluid swirl flow, characterized in that a pump that circulates the gas and a gas suction pipe that sucks gas on the suction side of the pump are installed. 2. The gas-liquid contact device according to claim 1, wherein the swirl flow generating device includes a liquid suction pipe extending toward a gas-liquid mixed fluid ejection opening provided in the lower end plate at a central portion of the upper end plate. 3. The gas according to claim 1, wherein the lower end plate of the swirl flow generator has an inclined surface in which the inner surface of the swirl flow generation container descends from the cylindrical wall of the container toward the fluid ejection opening. Liquid contact device. 4. The gas-liquid contact device according to claim 1, wherein the gas-liquid mixed fluid inflow port is arranged so that the gas-liquid mixed fluid flowing into the swirl flow generation container flows in an inclined downward direction. 5. The gas-liquid contact device according to any one of claims 1 to 4, wherein the gas suction amount is 6 vol% or less of the liquid sucked by the pump.

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