JPH04322731A - Method and device for dissolution of gas - Google Patents

Abstract

PURPOSE:To offer the method and device to dissolve an enough amt. of gas in a liquid. CONSTITUTION:A liquid is injected in a helical state from an annular injection port 38 for liquid under the liquid surface to form a fast conical vortex. At a same time, gas is injected from an gas injection port provided inside of the injection port 38 for liquid in order to bring the gas into contact with the fast vortex. Thus, the gas is atomized and forcedly mixed and diffused into superfine bubbles in the liquid.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas dissolving device for dissolving air, oxygen, carbon dioxide, and other gases into a liquid.

0002

[Prior Art] One example of this type of prior art is:
As shown in FIG. 7, centrifugal force is applied to the water by the rotation of the impeller 2 directly connected to the submersible motor 1, and the negative pressure generated on the outer circumference of the impeller 2 due to this centrifugal force is used to create a suction pipe 3.
An apparatus is known in which air is sucked from the atmosphere, a gas-liquid mixed flow is discharged from the discharge port 4 in a swirling state, and the air is dissolved in the wastewater in the treatment tank T. Note that reference numeral 5 indicates a power cord for driving the underwater motor 1.

[0003] As a second example,
A gas dissolving device shown in No. 290 is known. As shown in FIG. 8, the sludge water in the treatment tank T is forcibly circulated by the pump P and the liquid sending pipe 6, and the air sucked from the air suction pipe 7 is ejected from the spout 6a together with the circulating sludge water. , the structure is such that air is dissolved in the sludge water in the treatment tank T. In addition, an injection pipe 8 is located in front of the injection port 6a.
a to 8c are installed one above the other, and the air fed under pressure from the blower B is supplied between the injection pipes through the air supply pipe 9.

0004

[Problems to be Solved by the Invention] However, in the first prior art described above (see FIG. 7), although the solubility of air is generally good, the underwater motor 1 needs to have a watertight structure, and the impeller 2 The provision of mechanical stirring means such as the above inevitably increases the size and cost of the apparatus. Furthermore, since a large-sized device is disposed within the processing tank, there is a problem in that the processing tank also needs to be increased in size in consideration of the space for arranging the device.

On the other hand, in the second prior art (see FIG. 8),
Although the problem of the first prior art has been solved, an injection tube is essential to enhance the mixing effect of air and liquid, and the solubility of air is not that high compared to the prior art. Ta. The present invention was developed in view of the problems of the prior art, and its first purpose is to inject gas into a liquid in the form of ultrafine bubbles to dissolve a sufficient amount of gas in the liquid. The second objective is to provide a gas dissolving device that has a simple structure, is inexpensive, does not require a large liquid tank, and can achieve high gas solubility.

[0006]

[Means for Solving the Problems] In order to achieve the first object, in the gas dissolving method according to claim 1, the liquid is injected forward in a swirling state from an annular liquid injection port below the liquid surface. A tapered conical high-speed vortex is formed, and the gas ejected from the gas outlet inside the liquid injection port is brought into contact with the high-speed vortex and crushed into fine bubbles.

In order to achieve the second object, the gas dissolving apparatus according to claim 2 has a liquid tank filled with liquid, and a suction port and a discharge port opening into the liquid tank. and a circulation pipe for circulating the liquid in the tank,
A pump is provided in the middle of the circulation pipe to pump the liquid in the pipe, an ejector-type gas-liquid mixture injection nozzle is provided at the outlet of the circulation pipe, and a gas to be dissolved is sent to the injection nozzle. A gas dissolving device comprising: a gas supply pipe that communicates the injection nozzle with the gas supply pipe; and an annular swirl chamber formed at a position surrounding the gas supply pipe; A swirl guide hole extends in a spiral shape into the swirl chamber, introduces the circulating liquid supplied from the circulation pipe into the swirl chamber at high speed, and forms a high-speed swirl flow in the swirl chamber, and surrounds a gas jet port of the swirl chamber. The liquid injection port is formed at a position and is configured to include an annular liquid injection port that injects and forms a tapered conical high-speed vortex stream in front of the gas injection port.

According to a third aspect of the present invention, in the gas dissolving apparatus according to the second aspect, the pump is installed at the liquid external piping position of the circulation pipe. According to a fourth aspect of the present invention, in the gas dissolving apparatus according to the second aspect, a blower for forcibly supplying gas is provided in the air supply pipe. The gas dissolving device according to claim 5 includes a liquid tank filled with liquid, a circulation pipe having a suction port and a discharge port opening into the liquid tank, and for circulating the liquid in the tank; A pump is provided in the middle of the circulation pipe to pump the liquid in the pipe, an ejector-type gas-liquid mixture injection nozzle is provided at the outlet of the circulation pipe, and a gas to be dissolved is sent to the injection nozzle. A gas dissolving device comprising a gas supply pipe, wherein the injection nozzle is communicated with the gas supply pipe, and the gas suctioned under negative pressure by pressure feeding of the circulating fluid supplied from the circulation pipe is sucked together with the circulating fluid. A gas jet to be injected, an annular swirl chamber formed in a position surrounding the gas jet, and circulating liquid supplied from the circulation pipe are introduced into the swirl chamber at high speed to create a high-speed swirling flow in the swirl chamber. and an annular liquid injection port that is formed at a position surrounding the gas injection port of the swirl chamber and that forms a tapered conical high-speed vortex in front of the gas injection port. This is what I did.

According to a sixth aspect of the present invention, in the gas dissolving apparatus according to the fifth aspect, the pump is installed at the liquid external piping position of the circulation pipe.

0010

According to claim 1, the liquid injected from the annular liquid injection port forms a tapered conical high-speed vortex, and the gas ejected from the gas injection port is crushed by contact with this high-speed vortex,
The liquid is forced to mix and diffuse into ultrafine bubbles, increasing the surface area of contact between the liquid and gas.

In the second aspect of the present invention, the high-speed swirling flow of the circulating fluid formed in the vortex chamber is injected from the annular liquid jet port in front of the gas jet port to form a tapered conical high-speed vortex flow. Further, along with this injection of the circulating fluid, negative pressure is generated at the gas outlet, and gas is sucked and ejected from the gas outlet due to this negative pressure. As soon as the gas is sucked and ejected from the gas nozzle, it is injected from the liquid nozzle and crushed by the high-speed vortex formed around the gas, forced to mix and diffuse into ultrafine bubbles, and the liquid and gas come into contact with each other. Surface area increases.

[0012] In the third aspect, since the pump is installed outside the liquid, there is no need to consider a watertight structure, and the pump structure becomes simple. Further, in the fourth aspect of the present invention, since the blower forcibly supplies gas from the gas supply pipe to the gas outlet, a large amount of gas can be ejected from the gas outlet. In claim 5, the high-speed swirling flow of the circulating fluid formed in the swirl chamber is injected from the annular liquid jet port to the front of the gas jet port, forming a tapered conical high-speed swirl flow. From the gas jet port inside the annular liquid jet port, the gas sucked in by the pressure feeding of the circulating fluid is jetted out together with the circulating fluid. As soon as the gas is ejected from the gas nozzle, it is injected from the liquid nozzle and is crushed by the high-speed vortex formed around the gas, forced to mix and diffuse into ultrafine bubbles, and the surface area of contact between the liquid and gas is increases.

[0013] In claim 6, as in claim 3, there is no need to take watertight measures for the pump, and the pump structure is simplified.

[0014]

Embodiments Next, embodiments of the present invention will be explained based on the drawings. Figures 1 to 4 show an embodiment in which the present invention is applied to wastewater treatment. Figure 1 is an overall schematic diagram of a gas dissolving device, and Figure 2
is a front view of an ejector-type vortex-type gas-liquid mixture injection nozzle which is a main part of the gas dissolving device, FIG. 3 is a longitudinal cross-sectional view of the same nozzle (a cross-sectional view along line III-III shown in FIG. 2), and FIG. FIG. 3 is a perspective view of a turning guide hole forming member in which a turning guide hole is formed.

As shown in FIG. 1, the gas dissolving device for wastewater treatment includes a backing tank 10 filled with wastewater containing BOD components, a forced circulation line 20 for forcibly circulating the wastewater in the backing tank 10, and a circulation line 20 for forcedly circulating the wastewater in the backing tank 10. An ejector-type whirlpool gas-liquid mixture injection nozzle (hereinafter simply referred to as an injection nozzle) 30 installed at the circulating sewage outlet 22b of the line 20, and an air suction pipe 40 that supplies air to the injection nozzle 30.
It has a very simple structure consisting of

The forced circulation line 20 has a suction port 22a and a discharge port 22b located inside the buck tank 10, and a circulation pipe 22 extending outside the buck tank, and is provided in the middle of this circulation pipe 22 to forcefully pump circulating wastewater. It is composed of a pump 24. As shown in FIGS. 2 and 3, the injection nozzle 30 includes a gas injection port 32 with a circular cross section that communicates with the air suction pipe 40, an annular swirl chamber 34 surrounding the gas injection port 32, and a gas injection port 32 that communicates with the air suction pipe 40. A swirl guide hole 36 extending spirally from the outer periphery of the outlet 32 to the swirl chamber 34 and an annular liquid injection port 38 formed on the side of the swirl chamber 34 facing the gas injection port 32 are provided in the nozzle casing 31 . It has a formed structure.

A connecting portion 31a is formed at the rear end of the nozzle casing 31 for attachment and integration with the circulating sewage discharge port 22b of the circulation pipe 22, and is connected to the circulating sewage supply chamber 37 formed at the rear of the nozzle casing. Sewage is supplied from the circulation pipe 22. The circulating wastewater supply chamber 37 communicates with a swirl chamber 34 formed in the front part of the nozzle casing via a passage 37a extending forward, an annular chamber 37b, and a swirl guide hole 36. As shown in FIGS. 2 and 4, the swirl guide hole 36 spirally extends from the annular chamber 37b to the swirl chamber 3 in front.
4, and when the circulating wastewater passes through this swirl guide hole 36, it becomes a high-speed flow. In the vortex chamber 34, a swirling flow is formed by the high-speed flow guided from the swirling guide hole 36, and the high-speed swirling flow is injected from the narrowed annular liquid injection port 38 toward the front of the gas injection port 32, and the high-speed swirling flow is injected with the symbol O. A tapered conical high-speed vortex is formed with the apex at (see Fig. 3). The tip 38a of the circular pipe-shaped cylindrical portion 33 defining the gas jet port 32 and the annular liquid jet port 38 has a tapered shape, and the direction of jetting the circulating wastewater is directed toward the axis. That is, the focal point O of the conical high-speed vortex is located near the liquid injection port 38, thereby enhancing the forced mixing effect of the high-speed vortex.

On the other hand, the gas outlet 32 is connected to the air suction pipe 4.
0, and when circulating wastewater is injected from the liquid injection port 38, a negative pressure is generated within the gas injection port 32, so air is sucked and ejected from the gas injection port 32 due to this negative pressure. (See the white arrow in Figure 3). The air suctioned and ejected from the gas ejection port 32 comes into contact with the conical high-speed vortex formed by the liquid ejection port 38, is crushed, and is forcedly mixed and diffused to become ultrafine particle-like bubbles and dissolved in the wastewater. . Note that reference numeral 42 is a valve provided on the air suction pipe 40, which is adapted to adjust the amount of air sucked into the gas outlet 32 under negative pressure, that is, the amount of air ejected from the gas outlet 32.

The nozzle casing 31 includes a cylindrical casing base 31a in which a circulating sewage supply chamber 37, a passage 37a, an annular chamber 37b, and an air suction pipe connection port 31c are formed, and a cylindrical casing base 31a on the front surface of the casing base 31a. It consists of a casing front part 31b that is assembled and integrated. The casing front part 31b is a cap type in which a central hole is formed that forms the outer peripheral edge of the liquid injection port 38, and cooperates with a swirl guide hole forming member 35 (see FIG. 4) in which a swirl guide hole 36 is formed. This forms a vortex chamber 34 and forms a liquid injection port 38 in cooperation with the inner cylindrical portion 33 forming the gas injection port 32 . Note that reference numeral 34a in FIG. 4 indicates a concave surface portion forming the back wall of the swirl chamber 34. As shown in FIG. The casing base portion 31a and the casing front portion 31b are fastened together with a nut 39. The turning guide hole forming member 35 has a substantially truncated conical shape with a central through hole 35a, and the turning guide hole forming member 35 is fitted onto the inner cylindrical portion 33, and the turning guide hole forming member 35 is rotated by a compression coil spring 35b. It is pressed against the inside of the casing front portion 31b.

The nozzle 30 is assembled in the following manner. First, the inner cylindrical part 33 is fitted into the front end side insertion hole 31a1 of the casing base 31a, and the spring 35b and the turning guide hole forming member 35 are sequentially assembled to this cylindrical part 33. Then, cover the casing front part 31b so as to cover the turning guide hole forming member 35, and finally tighten the nut 39,
Integrated as a nozzle.

As described above, in the gas dissolving device according to the present embodiment, the air sucked and ejected from the gas ejection port 32 comes into contact with the conical high-speed vortex of circulating wastewater sprayed from the annular liquid injection port, and is crushed. The mixture is forced to mix and diffuse, resulting in ultrafine bubbles that cannot be obtained using conventional equipment. Therefore, the contact surface area between gas and liquid in the wastewater is increased, and a large amount of air can be dissolved in the wastewater, and the solubility of air in the wastewater is significantly improved compared to conventional methods and devices. Furthermore, since the solubility of air in wastewater can be significantly increased, the action of decomposing and removing BOD components by microorganisms is activated, and the efficiency of wastewater treatment can be significantly improved.

Furthermore, since the device of this embodiment sucks air using an ejector method, there is no need for an energy source such as a blower for supplying air, leading to savings in energy consumption. Furthermore, in order to construct the apparatus of this embodiment, it is sufficient to simply install the compact ejector-type vortex-type gas-liquid mixture injection nozzle 30 shown in this embodiment at the circulating liquid discharge port of the circulation pipe in a conventional gas dissolving apparatus. Construction is also very easy.

Although the above embodiment has a structure in which air is self-supplied by an ejector system that utilizes negative pressure caused by jetting liquid, a blower is provided in the air suction pipe 40 to force the air through the gas jet port. 32, and in this case, the dissolution rate of air can be adjusted by adjusting the amount of air supplied by the blower.

FIG. 5 shows a longitudinal sectional view of an ejector-type vortex gas-liquid mixture injection nozzle which is a main part of another embodiment of the present invention, and corresponds to FIG. 3. The injection nozzle 30 in the first embodiment described above has a structure in which the gas is sucked and ejected from the gas injection port 32 by utilizing the negative pressure when circulating wastewater is injected from the annular liquid injection port 38. However, the injection nozzle in this embodiment has a structure in which the circulating wastewater is also supplied to the gas outlet 32, and air is injected from the gas outlet 32 together with the circulating wastewater. That is, the upstream side of the communication portion of the gas outlet 32 with the air suction pipe 40 communicates with the circulating wastewater supply chamber 37 via the small diameter passage 32a. Therefore, when the circulating sewage is forced forward from the small diameter passage 32a at high speed, air is sucked under negative pressure from the air suction pipe 40, and the air and circulating sewage are injected together from the gas outlet 32. The gas injected together with the wastewater comes into contact with the high-speed vortex, is crushed, forced to mix and diffuse, and is dissolved into the wastewater in the form of ultrafine bubbles.

In this second embodiment, the air suction force (ejector action) within the gas jet port 32 is stronger than in the first embodiment, so if the air is forcibly supplied by a blower, the same amount of air can be supplied. , which has the advantage of increasing the dissolution rate of air. FIG. 6 shows another embodiment in which the present invention is applied to sewage treatment, and is an overall schematic diagram of a gas dissolving device.

In this embodiment, a small liquid circulation submersible pump 124 having a liquid suction port 122a and a discharge port 122b is installed in the buck tank 10, and an injection nozzle 30 is installed at the liquid discharge port 122b of the submersible pump. It becomes. The rest is the same as the first embodiment described above, and the explanation thereof will be omitted by giving the same reference numerals. In this third embodiment, it is only necessary to install the injection nozzle 30 at the liquid discharge port 122b of a small, inexpensive submersible pump, and piping corresponding to the circulation pipe 22 of the first embodiment is not required. Therefore, the construction is easy and the equipment cost is very low.

In the above embodiments, the present invention was applied to sewage treatment, but the present invention is not limited to sewage treatment technology, but is applicable to technology for dissolving various gases in liquids. Needless to say, it is widely applicable.

[0028]

Effects of the Invention As is clear from the above description, according to the gas dissolving method and device according to the present invention, the gas ejected from the gas jet port is crushed by the high-speed liquid vortex jetted from the liquid jet port, resulting in forced mixing. Since the bubbles are diffused into ultrafine particle-like bubbles, the contact surface area between the liquid and the gas increases, and the gas can be dissolved into the liquid in the liquid tank with high efficiency.

Furthermore, since the gas dissolving device according to the present invention has a simple configuration and high dissolving efficiency can be obtained, the cost of the device is low and the liquid tank can be small. Further, in claims 3 and 6, since the pump is provided outside the liquid, there is no need to provide the pump with means such as a liquid seal structure, and the pump has a simple structure and is advantageous in terms of cost. According to the fourth aspect of the present invention, the gas is forcibly supplied to the gas jet port by the blower, so that the dissolution rate of the gas is increased.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and is an overall schematic diagram of a gas dissolving device for wastewater treatment.

[Fig. 2] Front view of the ejector-type vortex-type gas-liquid mixture injection nozzle, which is the main part of the gas dissolving device.

[Fig. 3] Longitudinal cross-sectional view of the nozzle (line III-I shown in Fig. 2)
sectional view along II)

[Fig. 4] Perspective view of the turning guide hole forming member

FIG. 5 is a vertical cross-sectional view of an ejector-type whirlpool gas-liquid mixture injection nozzle which is a main part of another embodiment of the present invention.

FIG. 6 is a diagram showing still another embodiment of the present invention, and is an overall schematic diagram of a gas dissolving device for wastewater treatment.

[Fig. 7] Diagram showing the first conventional technology

[Fig. 8] Diagram showing the second conventional technology

[Explanation of symbols]

10 Liquid tank (bucking tank) 22 Circulation pipe 22a Suction port 22b Discharge port 24 Pump 24A Liquid circulation submersible pump 30 Ejector type whirlpool type gas-liquid mixture injection nozzle 3
2 Gas jet port 34 Whirlpool chamber 36 Turning guide hole 38 Liquid jet port

Claims (6)

[Claims] [Claim 1] Liquid is injected forward in a swirling state from an annular liquid injection port below the liquid surface to form a tapered conical high-speed vortex, and gas ejected from a gas injection port inside the liquid injection port is A gas dissolving method characterized by bringing the gas into contact with the high-speed vortex to crush it into fine bubbles. 2. A circulation pipe having a liquid tank filled with liquid, a suction port and a discharge port opening into the liquid tank, and for circulating the liquid in the tank, and a circulation pipe disposed in the middle of the circulation pipe. a pump that is provided to pump the liquid in the pipe; an ejector-type gas-liquid mixture injection nozzle provided at the outlet of the circulation pipe; and a gas supply pipe that supplies the gas to be dissolved to the injection nozzle. In the gas dissolving device, the injection nozzle includes a gas injection port communicating with the gas supply pipe, an annular swirl chamber formed at a position surrounding the gas injection port, and a spiral-shaped swirl chamber in the swirl chamber. A swirling hole is formed at a position surrounding a gas jet port of the swirling chamber, and a swirling hole is formed at a position surrounding a gas jet port of the swirling chamber to introduce the circulating liquid supplied from the circulation pipe into the swirling chamber at high speed to form a high-speed swirling flow in the swirling chamber. 1. A gas dissolving device comprising: an annular liquid injection port that injects and forms a tapered conical high-speed vortex in front of the injection port. 3. The liquid dissolving apparatus according to claim 2, wherein the pump is installed at a position of the liquid external piping of the circulation pipe. 4. The gas dissolving device according to claim 2, wherein the air supply pipe is provided with a blower for forcibly supplying gas. 5. A circulation pipe having a liquid tank filled with liquid, a suction port and a discharge port opening into the liquid tank, and for circulating the liquid in the tank, and a circulation pipe disposed in the middle of the circulation pipe. a pump that is provided to pump the liquid in the pipe; an ejector-type gas-liquid mixture injection nozzle provided at the outlet of the circulation pipe; and a gas supply pipe that supplies the gas to be dissolved to the injection nozzle. In the gas dissolving device, the injection nozzle communicates with the gas supply pipe and is a gas injection port through which gas sucked under negative pressure by pressure feeding of the circulating liquid supplied from the circulation pipe is injected together with the circulating liquid. , an annular swirl chamber formed at a position surrounding the gas jet port, and a swirl guide hole that introduces the circulating liquid supplied from the circulation pipe into the swirl chamber at high speed to form a high-speed swirl flow in the swirl chamber. and an annular liquid injection port that is formed at a position surrounding the gas injection port of the swirl chamber and that injects and forms a tapered conical high-speed vortex in front of the gas injection port. Device. 6. The liquid dissolving apparatus according to claim 5, wherein the pump is installed at a position of the liquid external piping of the circulation pipe.