JPH11137989A - Gas-liquid contact method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas-liquid contact method and the device capable of efficiently dissolving a gas in a liquid or allowing the gas to react with the liquid. SOLUTION: The gas is highly efficiently dissolved in the liquid or allowed to react with the liquid by combing gas-liquid contact vessels 1a-1d verically into multistages, which is for efficiently dissolving the gas into the liquid or allowing the gas to react with the liquid by continuously sucking the gas into the liquid by the action of the negative pressure generated in the liquid in the back face of the rotating impellers 8a-8d (8) in the rotating direction and generating a large quantity of fine bubbles by the vortex flow generated by the rotation of the impeller 8 and the shearing force of the impeller 8, and supplying the liquid to the uppermost vessel 1a, making the liquid to overflow successively to the lower vessel to recover in the lowermost vessel 1d, introducing the gas into the lowermost vessel 1d, inhaling the gas successively to the upper vessel to discharge at the uppermost vessel 1a to make counter current flow compactly without using power except for the rotation of the impellers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid contact method and apparatus capable of efficiently dissolving or reacting a gas with a liquid.

[0002]

2. Description of the Related Art The purpose of dissolving or reacting a gas with a liquid is to chemically react a gas or a substance contained in the liquid with a gas, to cause an impurity in the liquid to adhere to the gas and to float, and to dissolve the gas in the liquid. In some cases, the specified gas is replaced with another gas, or a specific gas-dissolved liquid in which a specific gas is dissolved in a liquid is produced. In any of the above cases, the most important point of the gas-liquid contact device is to increase the gas-liquid contact area to promote mass transfer between gas and liquid.

[0003] Conventionally, as a gas-liquid contacting device for enlarging the gas-liquid contact area to promote mass transfer between gas and liquid, a diffuser tube is disposed at the bottom of a container and a gas diffuser system is used to send gas as bubbles into the liquid. An ejector system in which an ejector is arranged in front of a container and gas is sent as bubbles to the bottom of the container together with the liquid, and a pressurizing method in which gas is pressurized in the liquid and then gas-liquid contacted by bubbles generated when the pressure is reduced, is generally used. ing.

Further, as another gas-liquid mixing device, a gas is continuously sucked into a liquid by using a negative pressure generated on the back of a rotating impeller, and a vortex generated by rotation of the impeller and a shear of the impeller are generated. Self-priming gas-liquid mixing device that generates a large amount of fine bubbles by force (Japanese Patent Publication No. 62-1524)
No. 9, JP-B-62-34436, JP-B-62
-34437, JP-B-62-34438)
Etc. are known.

[0005]

The gas-liquid contact device of the diffuser type has a limit on the contact between the gas and the liquid. In applications requiring a large gas-liquid contact area, the height of the container (tower height) is high.
Has to be extremely high. In addition, the ejector-type gas-liquid contact device requires a considerable pressure on the gas supply side, and in applications where a large gas-liquid contact area is required as in the case of the diffuser tube type, the container height (tower height) is reduced. There is a problem that it must be extremely high. Further, the pressurized gas-liquid contact device needs to pressurize the inside of the liquid container, and there is a problem that a large amount of unreacted gas or undissolved gas is generated when the pressure is reduced.

A conventional self-priming gas-liquid mixing apparatus is compact and inexpensive in running cost and can mix gas as fine bubbles in a liquid. However, when a gas dissolved in a liquid is replaced by another gas. In the case of producing a specific gas-dissolved liquid in which a specific gas is dissolved in a liquid, there is a problem that the amount of gas used is large and the efficiency is low.

An object of the present invention is to provide a gas-liquid contact method and apparatus which solve the above-mentioned disadvantages of the prior art, are compact, easily run, and can dissolve or react a gas in a liquid with high efficiency. It is in.

[0008]

According to a first aspect of the present invention, there is provided a gas-liquid contact method, wherein a gas is continuously sucked into a liquid by the action of a negative pressure generated in the liquid on the back side in the rotation direction of the rotating impeller. The vortex generated by the rotation of the impeller and the shearing force of the impeller generate a large amount of fine bubbles, and a plurality of gas-liquid contact tanks for dissolving or reacting gas efficiently in the liquid are combined in series in the vertical direction of the tank. The first
The gas is supplied to the tank, sequentially overflows to the rear tank, is collected in the final tank, and gas is introduced into the final tank, sucked into the previous tank sequentially, and discharged in the first tank.

As described above, the gas is continuously sucked into the liquid by the action of the negative pressure generated in the liquid behind the rotating impeller in the rotation direction, and the vortex generated by the rotation of the impeller, the shear force of the impeller and A large number of fine bubbles are generated, and a plurality of gas-liquid contact tanks for efficiently dissolving or reacting a gas in a liquid are combined in series in the vertical direction of a plurality of tanks,
The liquid is supplied to the first tank, overflows sequentially to the rear tank, and is recovered in the final tank. Gas is introduced into the final tank, is sucked into the previous tank, and is discharged in the first tank. The liquid and gas in the tank can be moved without using only the power to rotate the impeller, and the gas is converted into fine bubbles and brought into countercurrent contact with the liquid, so the difference in purity of the introduced gas (partial pressure difference) is used without loss. The gas can be dissolved or reacted with the liquid efficiently.

According to a second aspect of the present invention, there is provided a gas-liquid contact device, wherein a rotating shaft having an impeller at a lower portion is provided in a container containing a liquid having a gas inlet and a gas outlet and a liquid inlet and a liquid recovery port. A self-priming microbubble generator in which a lower opening of a cylindrical body through which the rotating shaft penetrates is arranged with a gap kept between the upper end of the impeller and a gas inlet just above the opening of the cylindrical body and a gas in the container. A plurality of gas-liquid contact tanks with inlets connected by piping are arranged in series in the vertical direction of the tank, and the gas inlet of the gas-liquid contact tank of the upper tank and the gas exhaust port of the lower tank are connected by piping,
In addition, the liquid recovery port of the gas-liquid contact tank of the upper tank and the liquid introduction port of the lower tank are connected by a pipe, and the liquid supply pipe is connected to the liquid introduction port of the uppermost tank to overflow sequentially to the next tank, and the lowermost tank. A gas inlet tube is connected to the gas inlet of the lower impeller, and the gas in the lower tank is sucked by the action of the negative pressure generated in the liquid on the back side in the rotating direction of the rotating impeller, and the gas is exhausted from the gas outlet of the uppermost tank. .

As described above, a plurality of gas-liquid contact tanks provided with a bubble generator are arranged in series in the vertical direction, and the gas inlet of the gas-liquid contact tank of the upper tank and the gas exhaust port of the rear tank are communicated by piping. The pipe connects the liquid recovery port of the gas-liquid contact tank in the upper tank to the liquid inlet in the rear tank, connects the liquid supply pipe to the liquid inlet in the uppermost tank, and connects the gas inlet to the gas inlet in the lower tank. By connecting the inlet pipe, the liquid continuously supplied to the liquid inlet of the uppermost tank overflows sequentially and is naturally discharged from the liquid recovery port of the last tank, and the gas sucked from the lowermost tank is The gas is successively sucked by the action of the negative pressure generated in the liquid on the back side of the rotating impeller of the upper tank in the rotating direction, and is discharged from the gas exhaust port of the uppermost tank, forming gas into fine bubbles and sequentially moving toward the liquid. Flow contact, the purity difference (partial pressure difference) Scan without available gas can be a efficiently dissolved or reaction liquid.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS When a rotating shaft of an impeller of a gas-liquid contact tank provided with the bubble generating device is rotated by a drive motor, the impeller rotates in the liquid to generate a vortex, and the liquid in the back of the impeller rotates. Negative pressure is generated therein, and gas is automatically sucked from the rear tank through the gas inlet to the lower part of the cylinder from the pipe, and is mixed into the vortex. The gas mixed into the vortex becomes a large amount of fine bubbles by the vortex and the impeller shear force, and the contact area between the liquid and the gas increases, so that the gas is efficiently dissolved or reacted in the liquid. Further, by arranging a plurality of gas-liquid contacting tanks in series in the vertical direction of the tanks, the liquid and the gas are sequentially brought into countercurrent contact, so that the purity difference (partial pressure difference) of the introduced gas can be utilized without loss, and It can be dissolved or reacted efficiently.

In the present invention, the impeller provided below the rotating shaft is fixed to a plate-like one to eight below the rotating shaft. When a plurality of impellers are used, each free end is fixed in a radially expanding manner. I do. The depth of the opening at the lower part of the cylindrical body for generating fine bubbles may be about 100 mm or more from the liquid level, and is preferably 300 to 500 mm. Further, the gap between the upper end of the impeller and the opening end of the lower portion of the cylindrical body is such that the gas can be sucked by effectively utilizing the negative pressure generated on the back surface in the rotation direction of the impeller, that is, 10 mm or less, preferably 2 to 5 mm or less. . If the diameter of the opening at the lower part of the cylinder is significantly smaller than the rotating diameter of the impeller, liquid enters into the opening at the lower part of the cylinder, the initial load at the time of driving the rotating shaft increases, the gas suction efficiency, the fine bubbles Generation efficiency decreases. Further, since the rotating diameter of the impeller is usually much larger than the diameter of the rotating shaft, it is advantageous to make the cylinder larger in diameter at the lower part of the rotating shaft than at the upper part.

The rotation speed of the impeller is not particularly limited as long as a negative pressure capable of sucking gas is generated on the back surface in the rotation direction of the impeller, and is not particularly limited. However, since it is restricted by the rotation diameter and strength of the impeller, for example, 1000 rpm or more, Preferably, it is 1200 rpm or more.

The number of gas-liquid contacting tanks provided with the self-priming microbubble generator is vertically arranged in series.
A tank, three tanks or a combination of four or more tanks will be used. In addition, the plurality of gas-liquid contact tanks are arranged in series in the vertical direction, the gas-liquid contact tanks may be arranged in series in a staggered manner in the vertical direction, or the gas-liquid contact tanks may be connected and arranged vertically in the vertical direction, Alternatively, the gas-liquid contact tank may be connected and arranged stepwise in the vertical direction. In the case of vertically connecting and arranging vertically, one drive shaft can rotate the impeller of all the gas-liquid contact tanks by penetrating one rotating shaft from the first tank to the last tank.

In the self-priming microbubble generator used in the present invention, a rotary shaft having an impeller at the lower portion and a lower opening of a cylindrical body through which the rotary shaft passes are arranged with a gap kept between the upper end portion of the impeller. The structure is not limited to the self-priming microbubble generator, and any structure may be used as long as a negative pressure capable of inhaling gas is generated on the back side in the rotation direction of the rotating impeller. Tokiko Sho 62-1
No. 5,249, JP-B-62-34436, JP-B-62-34437, JP-B-62-34438, and the like can be used.

[0017]

Embodiment 1 The details of the gas-liquid contact method of the present invention will be described below with reference to FIGS. FIG. 1 is an overall explanatory view showing an example of a four-stage gas-liquid contact device operated by one drive motor of the present invention. FIG. 2 is a four-stage gas-liquid contact device operated by four drive motors of the present invention. FIG. 3 is an enlarged view of a main part of a self-priming microbubble generator at the bottom of FIG.

1 and 3, reference numerals 1a to 1d denote liquid introduction pipes 2a to 2d, liquid recovery pipes 3a to 3d, and gas introduction pipes 4.
a to 4d, containers for storing liquids having gas exhaust pipes 5a to 5d, which are vertically stacked. The liquid introduced into the container 1a from the liquid introduction tube 2a is connected to the liquid collection tube 3a of the container 1a and the liquid introduction tube 2b of the container 1b.
b, the liquid collection tube 3c of the container 1c is connected to the liquid introduction tube 2c, and the liquid collection tube 3c of the container 1c is connected to the liquid introduction tube 2d of the container 1d. It is configured to be collected outside from the collection pipe 3d.

Reference numeral 6 denotes a rotating shaft penetrating from the upper surface of the container 1a to near the bottom surface of the container 1d. A driving motor 7 is provided at the upper end of the rotating shaft 6. 8a to 8d are impellers fixed near the bottoms of the containers 1a to 1d of the rotating shaft 6, 9a
9d are cylindrical bodies surrounding the rotating shaft 6 hanging from the ceiling surface of each container 1a-1d, and the lower opening 1 of each cylindrical body 9a-9d.
The lower ends of 0a to 10d have a predetermined gap with the upper ends of the impellers 8a to 8d, for example, a gap of 2 to 5 mm.

The gas introduced into the gas introduction pipe 4d into the vessel 1d is sucked by the negative pressure on the back surface in the rotation direction generated by the rotation of each of the impellers 8a to 8d, rises into the upper space, and then rises into the gas exhaust pipe of the vessel 1d. 5d is connected to the gas introducing pipe 4c of the container 1c, the gas exhaust pipe 5c of the container 1c is connected to the gas introducing pipe 4b of the container 1b, and the gas exhaust pipe 5b of the container 1b is connected to the gas introducing pipe 4 of the container 1a. Therefore, it is configured to be sequentially sucked upward and exhausted from the gas exhaust pipe 5a of the container 1a.

With the above-described configuration, while the containers 1a to 1d are filled with the liquid, the drive motor 7 is driven while continuously introducing the liquid from the liquid introduction pipe 2a of the container 1a to drive the impellers 8a to 8d. When the impeller 8d is rotated, the impellers 8a to 8d rotate in each of the containers 1a to 1d to generate a vortex, and a negative pressure is generated in the liquid on the back surface of the impellers 8a to 8d in the rotation direction. Cylindrical body 9a-
Gas introduction pipe 4a near the lower openings 10a to 10d of 9d
The gas is sucked from .about.4d and mixed into the vortex. The gas mixed into the vortex becomes a large amount of fine bubbles due to the vortex and the shearing force of the impellers 8a to 8d, increases the contact area between the liquid and the gas, and rises in the liquid to the upper space of each of the containers 1a to 1d. During this time, it dissolves or reacts efficiently in the liquid.

The gas that has risen into the upper space of the containers 1a to 1d is connected to the gas exhaust pipe 5d of the container 1d and the gas introduction pipe 4c of the container 1c, and the gas exhaust pipe 5c of the container 1c and the container 1b.
Is connected to the gas introduction pipe 4b of the container 1b.
Since b is connected to the gas introduction pipe 4 of the container 1a, the gas is sequentially sucked upward and exhausted from the gas exhaust pipe 5a of the container 1a. On the other hand, the liquid continuously introduced from the liquid introducing tube 2a of the container 1a is connected to the liquid collecting tube 3a of the container 1a and the liquid introducing tube 2b of the container 1b, and the liquid collecting tube 3b of the container 1b is connected.
Is connected to the liquid introduction pipe 2c of the container 1c, and the liquid recovery pipe 3c of the container 1c is connected to the liquid introduction pipe 2d of the container 1d. During the collection, the gas sequentially comes into contact with a large number of fine bubbles, and the gas is efficiently dissolved or reacted.

In FIG. 2, reference numerals 21a to 21d denote containers each containing a liquid having liquid introduction pipes 22a to 22d, liquid recovery pipes 23a to 23d, gas introduction pipes 24a to 24d, and gas exhaust pipes 25a to 25d. They are arranged in multiple stages. The liquid introduced into the container 21a from the liquid introduction tube 22a is connected to the liquid collection tube 23a of the container 21a and the liquid introduction tube 22b of the container 21b, and is connected to the liquid collection tube 23 of the container 21b.
b is connected to the liquid introduction pipe 22c of the container 21c,
1c liquid recovery pipe 23c and container 21d liquid introduction pipe 22
Since d is connected, it overflows sequentially down,
It is configured to be collected outside from the liquid collection pipe 23d of the container 21d.

Reference numerals 26a to 26d denote rotating shafts penetrating to near the bottom of each of the containers 21a to 21d.
Drive motors 27a to 27d are provided at the upper end of d. 28a to 28d are impellers fixed to the rotating shafts 26a to 26d near the bottom of each of the containers 21a to 21d.
9a to 29d are cylindrical bodies surrounding the respective rotating shafts 26a to 26d hanging from the ceiling surface of each of the containers 21a to 21d, and the lower ends of the lower openings 30a to 30d of the cylindrical bodies 29a to 29d are
It has a predetermined gap between the upper ends of the impellers 28a to 28d, for example, a gap of 2 to 5 mm, and has a structure similar to that of FIG.

The gas introduction pipe 24 is formed in the container 21d by the negative pressure on the back surface in the rotation direction generated by the rotation of the impeller 28d.
After the gas sucked from the container d rises to the upper space of the container 21d, the gas exhaust pipe 25d of the container 21d and the container 21c
Is connected, the gas exhaust pipe 25c of the container 21c is connected to the gas introduction pipe 24b of the container 21b,
Since the gas exhaust pipe 25b of the container 21b is connected to the gas introduction pipe 24 of the container 21a, the gas is sequentially sucked upward and exhausted from the gas exhaust pipe 25a of the container 21a.

With the above configuration, the containers 21a to 21d are filled with the liquid, and the containers 21a to 21d are filled with the liquid.
While continuously introducing the liquid from the liquid introduction pipe 22a, the respective drive motors 27a to 27d are driven to drive the impellers 28a to 28d.
When the impeller 28d is rotated, the impellers 28a to 28d rotate in each of the containers 21a to 21d to generate a vortex, and a negative pressure is generated in the liquid on the back surface in the rotation direction of each of the impellers 28a to 28d. Cylindrical bodies 29a to 29d
Gas introduction pipes 24a to 24a near the lower openings 30a to 30d of
Gas is sucked from 24d and mixed into the vortex. The gas mixed in the vortex becomes a large amount of fine bubbles due to the vortex and the shearing force of the impellers 28a to 28d, increases the contact area between the liquid and the gas, and rises in the liquid to the upper space of each of the containers 21a to 21d. During this time, it dissolves or reacts efficiently in the liquid.

The gas rising to the upper space of the containers 21a to 21d is connected to the gas exhaust pipe 25d of the container 21d and the gas introduction pipe 24c of the container 21c, and the gas exhaust pipe 25c of the container 21c and the gas introduction pipe 24b of the container 21b. Are connected, and the gas exhaust pipe 25b of the container 21b and the gas introduction pipe 24a of the container 21a are connected, so that the gas is sequentially sucked upward and exhausted from the gas exhaust pipe 25a of the container 21a. On the other hand, the liquid continuously introduced from the liquid introduction tube 22a of the container 21a is connected to the liquid collection tube 23a of the container 21a and the liquid introduction tube 22b of the container 21b,
b is connected to the liquid introduction pipe 22c of the container 21c,
1c liquid recovery pipe 23c and container 21d liquid introduction pipe 22
Since d is connected, it overflows sequentially down,
During the recovery from the liquid recovery pipe 23d of the container 21d to the outside, the gas sequentially comes into contact with a large amount of fine bubbles to efficiently dissolve or react with the gas.

Example 2 A gas / liquid contacting apparatus according to the present invention of a four-tank type in which four gas-liquid contact tanks having the specifications shown in Table 1 are arranged in a staggered manner as shown in FIG. Was subjected to a deoxygenation test using nitrogen gas as a gas to reduce dissolved oxygen in water. Table 2 shows the conditions and results of the deoxidation test. In addition, the dissolved oxygen concentration in water was measured using the dissolved oxygen meter of the diaphragm electrode method.

[0029]

[Table 1]

[0030]

[Table 2]

As shown in Table 2, the dissolved oxygen concentration of 120 ppb in the treated water of Case 1 is sufficient for deoxygenation as a closed system cooling water which needs to suppress corrosion of pipes and the like, and a supply water for a general boiler. . The dissolved oxygen concentration in the treated water of Case 2 was 10 ppb, which was a level required for ultrapure water used for cleaning semiconductors.
Compared with other methods using nitrogen gas or other methods using different principles, the method of the present invention and the low running cost property determined from the required nitrogen gas amount and power consumption due to the compactness determined from the residence time of 5 minutes and The equipment is
It can be judged that it is very high performance.

Example 3 A gas-liquid contacting device according to the present invention of a three-tank type in which three gas-liquid contacting tanks having the specifications shown in Table 3 were arranged in a staggered manner was used. Water was used as a liquid, and oxygen gas was used as a gas. Using a gas mixture with ozone, an ozone absorption test into water was performed. Table 4 shows the conditions and results of the ozone absorption test. The ozone concentration in the gas was measured by an ultraviolet absorption method.

[0033]

[Table 3]

[0034]

[Table 4]

In this test, tap water was used. As shown in Table 4, when the inlet ozone gas concentration was at a level of 74 mg / l, the ozone absorption rate in tap water was a very high value of 85%.

[0036]

According to the gas-liquid contact method of the first aspect of the present invention, the gas is continuously sucked into the liquid by the action of the negative pressure generated in the liquid on the back side in the rotating direction of the rotating impeller.
A large number of fine bubbles are generated by the vortex generated by the rotation of the impeller and the shearing force of the impeller, and the unit operations for efficiently dissolving or reacting the gas in the liquid are combined in multiple stages. By overflowing the tank and collecting it in the lower tank, introducing gas into the lower tank, sequentially sucking it into the upper tank, exhausting it in the upper tank, and causing it to flow countercurrently, the gas is dissolved in the liquid with high efficiency or Can react.

According to a second aspect of the present invention, there is provided a gas-liquid contact device, comprising: a rotary shaft having an impeller at a lower portion in a container containing a liquid having a gas inlet and a gas outlet and a liquid inlet and a liquid recovery port. A self-priming type in which a cylinder through which the rotating shaft passes is opened into the liquid while keeping a gap with the upper end of the impeller, and a gas intake port immediately above the opening of the cylinder and a gas inlet port of the container are connected by piping. A gas-liquid contact tank equipped with a microbubble generator is arranged in multiple stages up and down, the gas inlet of the gas-liquid contact tank of the upper tank and the gas exhaust port of the lower tank are connected by piping, and the gas-liquid contact tank of the upper tank The liquid recovery port of the lower tank and the liquid inlet of the lower tank are connected by a pipe, and a liquid supply pipe is connected to the liquid inlet of the uppermost tank to overflow sequentially to the next tank, and a gas inlet pipe is connected to the gas inlet of the lower tank. Liquid on the back side of the rotating direction of the impeller By using the negative pressure generated in the tank, the gas in the lower tank is sequentially sucked and exhausted from the gas exhaust port in the uppermost tank, so that the counter flow can be realized compactly and without using any power other than rotating the impeller. In comparison, costs such as running costs and equipment costs can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall explanatory view showing an example of a four-stage gas-liquid contact device operated by one drive motor according to the present invention.

FIG. 2 is an overall explanatory view showing an example of a four-stage gas-liquid contact device operated by four drive motors of the present invention.

FIG. 3 is an enlarged view of a main part of the self-priming microbubble generator at the bottom of FIG. 1;

[Explanation of symbols]

 1a to 1d, 21a to 21d Containers 2a to 2d, 22a to 22d Liquid introduction pipes 3a to 3d, 23a to 23d Liquid recovery pipes 4a to 4d, 24a to 24d Gas introduction pipes 5a to 5d, 25a to 25d Gas exhaust pipe 6, 26a-26d Rotary shaft 7, 27a-27d Drive motor 8a-8d, 28a-28d Impeller 9a-9d, 29a-29d Cylindrical body 10a-10d, 30a-30d Lower opening

Claims (2)

[Claims] 1. A gas is continuously sucked into a liquid by the action of a negative pressure generated in a liquid behind a rotating impeller in a rotation direction, and finer is formed by a vortex generated by rotation of the impeller and a shear force of the impeller. Combine the unit operations to generate a large amount of bubbles and dissolve or react gas efficiently in the liquid in multiple stages, supply the liquid to the uppermost tank, overflow the liquid sequentially to the lower tank, collect the liquid in the lower tank, and collect the gas in the lower tank. A gas-liquid contact method, wherein the gas-liquid contact method is introduced into the lowermost tank, sequentially sucked into the upper tank, exhausted from the uppermost tank, and caused to flow countercurrently. 2. A rotating shaft having an impeller at a lower part thereof, and a cylindrical body through which the rotating shaft penetrates, in a container containing a liquid having a gas inlet and a gas outlet and a liquid inlet and a liquid recovery port. A gas-liquid contacting tank provided with a self-priming microbubble generator in which a gas inlet opening just above the opening of the cylindrical body and a gas inlet of the container are connected by piping so as to open into the liquid while keeping a gap with the upper end of the impeller. Are arranged in multiple stages, the gas inlet of the gas-liquid contact tank of the upper tank and the gas exhaust port of the lower tank are connected by piping, and the liquid recovery port of the gas-liquid contact tank of the upper tank and the liquid inlet of the lower tank are connected. Communicate by piping, connect the liquid supply pipe to the liquid introduction port of the uppermost tank and overflow sequentially to the next tank,
A gas inlet pipe is connected to the gas inlet of the lowermost tank, and the gas in the lower tank is sucked by the action of the negative pressure generated in the liquid on the back side in the rotating direction of the rotating impeller and exhausted from the gas outlet of the uppermost tank. A gas-liquid contact device, comprising: