JPH09299930A - Gas-liquid contacting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the dissolution efficiency of compressed air by arranging ejectors in a pressurized tank to jet a fluid mixture toward inner cylinders erected in a gas-liquid contacting bed and also installing plural trays in the gas-liquid contacting layer to form bypass flow passages for the fluid mixture flowing down in the pressurized tank. SOLUTION: A pressurized tank 2 of a gas-liquid contacting device 1 is provided with a compressed air feeding route 11b and a compressed air feeding route 11a, and a feed water feeding path 12b and a feed water feeding port 12a on tone upper part side and on the lower part side thereof respectively, and moreover, a liquid layer 4 consisting of pressurized water is formed therein. In a gas-liquid contacting bed 3, plural inner cylinders 5 are installed with the lower part thereof dipped in the water layer 4. Ejectors 6 are arranged below the inner cylinders 5. To the ejectors 6, the feed water feeding path 12b and air suction pipes 13 whose upper end part is made to face the gas-liquid contacting layer 3 are connected to jet a fluid mixture of air and feed water toward the inner cylinders 5. Also plural trays 7 are alternately installed in the gas-liquid contacting layer 3 to form pressurized water having fine bubbles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to pressurized air-dissolved water (hereinafter referred to as pressurized water) in a pressurized flotation device as a part of water treatment for separating sewage into clear water and sludge which is a pollutant. The present invention relates to a gas-liquid contact device for obtaining.

[0002]

2. Description of the Related Art A pressurized flotation separator is a device for removing suspended solids from treated raw water by mixing pressurized raw water with pressurized water to float and separate suspended solids in the treated raw water. It is used in a wide range of fields such as wastewater treatment in wastewater treatment plants and septic tanks, treatment of factory wastewater and leachate in landfills, rainwater treatment, replacement of first settling tank and final settling tank, scum separation concentration and excess sludge concentration. There is.

FIG. 3 (a) is a cross-sectional view schematically showing the structure of a pressure levitation separator for floating and separating suspended solids in treated raw water using pressurized water obtained by a conventional gas-liquid contactor. Is. The pressurized flotation device 20 includes a pressurized flotation tank 21 and a gas-liquid contact device 22 for obtaining pressurized water.
And a concentrate recovery device (not shown) mounted on the pressure floating tank 21.

The pressurized flotation tank 21 has a treated raw water inlet 21.
a, a pressurized water inlet 21b and a treated water outlet 21c are formed, and the treated raw water inlet 21a has a treated raw water inflow passage 2
3 is connected to the pressurized water inlet 21b, and a pressurized water inflow path 24 for sending pressurized water described below is connected to the pressurized water inlet 21b.

The pressure tank 25 constituting the gas-liquid contact device 22 has a compressed air supply port 25a and a raw water supply port 25.
b and the pressurized water discharge port 25c are formed, and the compressed air supply passage 25 from the air compressor 26 is provided in the compressed air supply port 25a.
7 is connected to the raw water supply port 25b, one end of which is connected to the treated water discharge passage 28 via a pump 29.
The other end of 0 is connected, and the high-concentration pressurized water is generated in the pressurized tank 25 by the supplied raw water and compressed air. The pressurized water discharge port 25c of the pressurized tank 25 is connected to the other end of a pressurized water inflow passage 24, one end of which is connected to the pressurized water inlet 21b of the pressurized flotation tank 21.

The treated raw water passes through the treated raw water inflow path 23,
Further, the pressurized water generated in the pressurized tank 25 is introduced into the pressurized levitation tank 21 through the pressurized water inflow path 24, and is uniformly mixed by the mixing device 31 in the pressurized levitation tank 21. A rectifying device 32 for promoting solid-liquid separation is provided in the pressurized flotation tank 21, and the treated water discharge port 21 is also provided.
A partition plate 33 for solid-liquid separation is provided on the c side.

Conventional gas-liquid contactor 22 for generating pressurized water
Is a pressurized tank 2 as shown in FIG.
5 is provided with a gas-liquid contact portion 22a made of a contact material such as a filler or a shelf, and a raw water supply passage 30 is provided by a pump 29.
The water to be pressurized, which has been sent via the air, is sprinkled from the upper part in the pressure tank 25, and the compressed air from the air compressor 26 and the gas-liquid contact part 22a are dissolved in the air, and the water is compressed to the bottom part of the pressure tank 25. A pressurized tank system for obtaining the pressurized water 34 is used.

Further, as shown in FIG.
The ejector 35 for gas-liquid mixing is installed outside the device, and the compressed air introduced from the air compressor 26 into the pressurized tank 25 and the pressure sent by the pump 29 via the raw water supply passage 30 should be pressurized. An ejector system in which water is mixed by the ejector 35 and pressure-fed into the pressure tank 25 is also adopted.

[0009]

In the former pressurized tank system, only the water to be pressurized is sprayed from the upper part of the pressurized tank 25 toward the gas-liquid contact portion 22a, so that the efficiency of dissolving compressed air is improved. In order to improve this efficiency even a little, it is possible to reduce the diameter of the contact material in the gas-liquid contact portion to increase the surface area, but as a result, the gap between the contact materials becomes narrower and There is a drawback that causes blockage. Therefore, in reality, a contact material having a too small diameter cannot be used. On the other hand, in the latter ejector system, the ejector 3 in which compressed air and water to be pressurized are installed outside the pressure tank 25
Since it is jetted into the pressurized tank 25 after being mixed by 5, the dissolution efficiency of the compressed air is poor as in the pressurized tank system, and the pressurized water branched from the pressurized water inflow path 24 is circulated to the ejector 35 by the circulation pump 36. To improve the dissolution efficiency by means such as recirculation to the inflow path, or by designing the pipe extending from the discharge port of the ejector 35 to the pressurizing tank 25 to be as vertical as possible. However, the circulation pump 36 and long piping are required separately,
Even if such measures are taken, there is a drawback that a satisfactory dissolution efficiency cannot be obtained.

An object of the present invention is to provide a gas-liquid contactor for generating pressurized water, which solves the above-mentioned problems associated with the conventional pressurized tank system and ejector system and has a high efficiency of dissolving compressed air.

[0011]

In order to achieve the above-mentioned object, the present invention is a gas-liquid contactor as a pressurized water producing means in a pressurized flotation device, comprising a pressurized tank,
A gas-liquid contact layer for bringing the air and water supplied into the pressurized tank into contact with each other, a liquid layer made of pressurized air-dissolved water generated by the air and water, and the gas-liquid contact layer were provided upright. An inner cylinder, and an ejector for ejecting a mixed fluid of air and the water taken in from the gas-liquid contact layer through an air suction pipe whose upper end faces the gas-liquid contact layer toward the inner cylinder. A gas-liquid contact device comprising: a plurality of shelves provided in the gas-liquid contact layer and configured to form a bypass flow path in the gas-liquid mixed fluid flowing down in the pressure tank.

The lower end of the inner cylinder faces the liquid layer, the ejector is located below the lower end of the inner cylinder, and the gas-liquid ejected from the ejector is ejected onto the upper inner wall of the pressure tank. It is effective to provide a dispersion plate to disperse the mixed fluid in each direction. The lower end of the inner cylinder is partitioned by a bottom plate, and the ejector has its lower side positioned in the liquid layer and its upper side penetrates the bottom plate to face the inside of the inner cylinder. It is also effective to provide at least one baffle inside the inner cylinder. Furthermore, it is more effective to provide an air diffuser for supplying air from outside the pressure tank to aerate the liquid layer.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view symbolically showing a first embodiment of a gas-liquid contactor for generating pressurized water according to the present invention. The gas-liquid contact device 1 includes a pressure tank 2, a gas-liquid contact layer 3, a liquid layer 4 of pressurized water, an inner cylinder 5, an ejector 6, and a plurality of shelves provided on the gas-liquid contact layer 3. 7 and the main part.

The pressure tank 2 is a closed container made of a rust preventive material such as stainless steel, and has an air compressor 11 on the upper side.
Is provided with a compressed air supply port 11a for introducing compressed air through the compressed air supply path 11b, and for introducing raw water through the raw water supply path 12b via the pump 12 on the lower side. A raw water supply port 12a is provided.

The compressed air supplied from the air compressor 11 and the raw water supplied via the pump 12 are supplied to the pressurized tank 2
High-concentration pressurized water having fine bubbles is generated in the gas-liquid contact layer 3 therein, and the liquid layer 4 made of the pressurized water is formed on the lower side.

In the gas-liquid contact layer 3, a plurality of inner cylinders 5, 5 are provided.
Are erected in such a manner that the lower ends of the inner cylinders 5 and 5 are exposed to the liquid layer 4. It is preferable that the required number of inner cylinders 5 and 5 are evenly provided in the pressurizing tank 2 at intervals, but a single number may of course be used depending on circumstances.

Ejectors 6 and 6 are provided at corresponding positions below the inner cylinders 5 and 5. This ejector 6,6
Is disposed with a slight gap between the discharge part and the lower ends of the inner cylinders 5, 5. The raw water supply passage 12b from the pump 12 and the air suction pipe 13 whose upper end faces the gas-liquid contact layer 3 are connected to the ejectors 6 and 6. The ejectors 6 and 6 mix the air taken in through the air suction pipe 13 and the raw water supplied from the pump 12, and eject the mixed fluid toward the inner cylinders 5 and 5. In this case, the height from the water surface of the liquid layer 4 to the upper inner wall of the pressure tank 2 is such that the fluid ejected from the ejectors 6 and 6 reaches the upper inner wall of the pressure tank 2 at a sufficient distance.
It is set in advance.

A plurality of shelf plates 7 are alternately provided between the inner wall of the pressure tank 2 serving as the gas-liquid contact layer 3 and the outer wall of the inner cylinders 5, 5 and between the outer walls of the inner cylinders 5, 5. It is provided. The mixed fluid ejected from the ejectors 6, 6 to the inner cylinders 5, 5 collides with the upper inner wall of the pressure tank 2 and changes its flow downward, and is indicated by arrows in the figure by the plurality of shelf plates 7 in the gas-liquid contact layer 3. As described above, sufficient contact is made during the formation of the bypass flow path to generate pressurized water having fine bubbles. This pressurized water is sent from the pressurized water discharge port 2b at the bottom of the pressurized tank 2 to a pressure floating separation device (not shown).

If an inverted triangular pyramidal dispersion plate 2a is provided on the inner wall of the upper portion of the pressure tank 2, the mixed fluid ejected from the ejectors 6 and 6 through the inner cylinders 5 and 5 will be described. However, the dispersion plate 2a disperses and flows down in each direction in the pressure tank 2, so that gas-liquid contact can be performed more efficiently. Further, another compressed air supply path 11c is provided from the air compressor 11 on the lower side of the pressurized tank 2 and the tip thereof is connected to the air diffuser 14 in the liquid layer 4 to aerate the liquid layer 4. By doing so, a higher concentration of pressurized water can be obtained.

The operation of the above-described first embodiment will be described. The compressed air from the air compressor 11 is introduced into the gas-liquid contact layer 3 from the upper side of the pressurized tank 2 via the compressed air supply path 11b. Raw water is introduced into the ejectors 6 and 6 provided below the water surface of the liquid layer 4 from the pump 12 via the raw water supply passage 12b, and the upper end portion is provided with the gas-liquid contact layer 3
The air is taken in from the air suction pipe 13 facing the above, and the mixed fluid is jetted toward the inner cylinders 5, 5.
The jetted fluid collides with the inner wall of the upper portion of the pressurized tank 2 and flows down in a dispersed manner, and is sufficiently in gas-liquid contact while forming a bypass flow path by the plurality of shelf plates 7 in the gas-liquid contact layer 3 and has fine bubbles. Generates pressurized water. The obtained pressurized water is the pressurized water discharge port 2b.
Taken out.

Next, FIG. 2 is a cross-sectional view schematically showing a second embodiment of the gas-liquid contactor for producing pressurized water according to the present invention. In the second embodiment, the parts and members used in the above-described first embodiment are designated by common reference numerals, and detailed description thereof will be omitted.

In the gas-liquid contact layer 3, a single inner cylinder 5 is erected concentrically with the pressure tank 2. This inner cylinder 5 is the liquid layer 4
A bottom plate 5a is provided at the lower end so as to be isolated from the bottom plate. Then, a plurality of ejectors (6 may be used depending on the case) may be provided at even intervals so that the upper side of the inner cylinder 5 is penetrated through the bottom plate 5a. To do. The lower sides of the ejectors 6 and 6 are submerged in the liquid layer 4, and the raw water supply passage 12b from the pump 12 is added to this.
And an air suction tube 1 whose upper end faces the gas-liquid contact layer 3
3 and 3 are connected. The ejectors 6 and 6 mix the air taken in through the air suction pipe 13 and the raw water supplied from the pump 12, and the mixed fluid is ejected toward the inside of the inner cylinder 5, Overflow from the top of.
In this case, if at least one baffle 5b is provided inside the inner cylinder 5, the air dissolving efficiency is further improved.

The jetted fluid overflowing from the upper end of the inner cylinder 5 is
The gas-liquid contact layer 3, that is, a plurality of shelf plates 7 provided alternately between the inner wall of the pressure tank 2 and the outer wall of the inner cylinder 5 is sufficient for forming a bypass flow path as shown by an arrow in the figure. To produce pressurized water with fine bubbles. This pressurized water is sent from the pressurized water discharge port 2b at the bottom of the pressurized tank 2 to a pressure floating separation device (not shown). In addition, a part of the generated pressurized water may be circulated to the raw water supply passage 12b via the circulation pump 15.

The operation of the above-described second embodiment will be described. Compressed air from the air compressor 11 is introduced into the gas-liquid contact layer 3 from the upper side of the pressurized tank 2 via the compressed air supply path 11b. Pump 1 for ejectors 6 and 6
Air suction pipe 1 in which raw water is introduced from 2 via a raw water supply passage 12b and the upper end of which faces the gas-liquid contact layer 3
The air is taken in from the inner cylinder 5
Erupts toward the inside of. Ejection fluid is baffle 5b
The water level of the inner cylinder 5 is raised while hitting against, and overflows from the upper end portion. Then, while the gas-liquid contact layer 3 forms the bypass flow path by the plurality of shelf plates 7, gas-liquid contact is sufficiently made to generate pressurized water having fine bubbles. The obtained pressurized water is taken out from the pressurized water discharge port 2b. The pressure tank 2
If another compressed air supply path 11c is provided on the lower side of the air compressor 11 and the tip of the compressed air supply path 11c is connected to the air diffuser 14 in the liquid layer 4 so that the liquid layer 4 is aerated, a higher pressure can be obtained. A concentration of pressurized water can be obtained.

[0025]

As described above, according to the gas-liquid contactor for generating pressurized water according to the present invention, the ejector is arranged inside the pressure tank and the inner cylinder is erected in the gas-liquid contact layer. In addition to ejecting the mixed fluid toward the gas-liquid contact layer, a plurality of shelves are provided to form a bypass flow path for the gas-liquid mixed fluid flowing down in the pressure tank. The compressed air is more efficiently dissolved than the method and ejector method, and in particular, by taking in the air in the gas-liquid contact layer from the upper end of the air suction pipe, the air that has been once dissolved by the ejector is further dissolved in air. Therefore, the dissolution efficiency can be further improved. Therefore, it is not necessary to make the contact material of the gas-liquid contact layer so dense, and sufficient gas-liquid contact can be achieved by forming the bypass flow path by a plurality of shelves without causing blockage.

In the first embodiment shown in FIG. 1, since the ejector is provided in the liquid layer and the mixed fluid is jetted from below the water surface, the liquid layer is agitated and air is dissolved by gas-liquid contact at the liquid layer interface. Be promoted. Then, the jetted fluid is dispersed and flows down in each direction in the pressure tank by the dispersion plate provided on the upper inner wall of the pressure tank 2, so that gas-liquid contact can be performed more efficiently.

Further, in the second embodiment shown in FIG. 2, since the mixed fluid is ejected from the ejector into the inside of the inner cylinder which is isolated from the liquid layer, the bubbles which cannot be completely dissolved by the ejector are sufficiently discharged in the inner cylinder. Can be dissolved in. Therefore, unlike the conventional ejector system, it is not necessary to provide a long pipe outside the pressure tank.

[Brief description of drawings]

FIG. 1 is a sectional view symbolically showing a first embodiment of a gas-liquid contactor for generating pressurized water according to the present invention.

FIG. 2 is a symbolic sectional view of a second embodiment of a gas-liquid contactor for generating pressurized water according to the present invention.

FIG. 3 (a) is a cross-sectional view schematically showing the structure of a pressurized flotation separator for floating and separating suspended solids in treated raw water using pressurized water obtained by a conventional gas-liquid contactor, FIG. 3B is a cross-sectional view that symbolically shows an example of a conventional gas-liquid contact device for generating pressurized water.

FIG. 4 is a symbolic sectional view showing another example of a conventional gas-liquid contactor for generating pressurized water.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Gas-liquid contact device 2 ... Pressurization tank 2a ... Dispersion plate 2b ... Pressurized water discharge port 3 ... Gas-liquid contact layer 4 ... Liquid layer 5 ... Inner cylinder 5a ... Bottom plate 5b ... Baffle 6 ... Ejector 7 ... Shelf plate 11 ... Air Compressor 11a ... Compressed air supply port 11b ... Compressed air supply route 11c ... Compressed air supply route 12 ... Pump 12a ... Raw water supply port 12b ... Raw water supply route 13 ... Air suction pipe 14 ... Diffuser 15 ... Circulation pump

Claims (6)

[Claims] 1. A gas-liquid contact device as a pressurized air-dissolved water producing means in a pressurized flotation device, comprising: a pressurized tank; and a gas-liquid contacting air and water supplied into the pressurized tank. A contact layer, a liquid layer composed of pressurized air-dissolved water generated by this air and water, an inner cylinder standing on the gas-liquid contact layer, and air suction with the upper end facing the gas-liquid contact layer. An ejector for ejecting a mixed fluid of air and the water taken from the gas-liquid contact layer through a pipe toward the inner cylinder,
A gas-liquid contact device comprising: a plurality of shelves provided in the gas-liquid contact layer and configured to form a bypass flow path in the gas-liquid mixed fluid flowing down in the pressure tank. 2. The gas-liquid contactor according to claim 1, wherein a lower end of the inner cylinder faces the liquid layer, and the ejector is located below the lower end of the inner cylinder. 3. The gas-liquid contact according to claim 1 or 2, wherein a dispersion plate for dispersing and flowing down a gas-liquid mixed fluid ejected from an ejector in each direction is provided on an upper inner wall of the pressure tank. apparatus. 4. The inner cylinder has a bottom end partitioned by a bottom plate, and the ejector has its lower side positioned in the liquid layer and its upper side penetrating the bottom plate to form an interior of the inner cylinder. The gas-liquid contact device according to claim 1, which is exposed to the air. 5. The gas-liquid contact device according to claim 4, wherein at least one baffle is provided inside the inner cylinder. 6. The gas-liquid contactor according to claim 1, wherein an air diffuser for supplying air from outside the pressure tank to aerate the liquid layer is provided in the liquid layer.