JPH07308569A - Bubble tower - Google Patents

Abstract

PURPOSE:To obtain a bubble tower capable of controlling the generation of bubbles by providing the tower with a draft tube and a cylindrical body arranged in the vicinity of the upper opening of the draft tube. CONSTITUTION:The bubble tower 11 is provided with a cylindrical tower main body 12, a gas supply pipe 13 connected to the tower bottom and a gas discharge pipe 14 connected to the top of the tower and a nozzle 15 is mounted at the tip part of the gas supply pipe 13. And the tower main body 12 is provided with the cylindrical draft tube 16 and the cylindrical body 17 arranged in the vicinity of the upper opening 16A of the draft tube 16. The cylindrical body 17 is cylindrically shaped and the diameter is smaller than that of the draft tube 16. And the cylindrical body 17 is concentric with the draft tube 16 and arranged so as to be located in the upper opening 16A of the draft tube 16. The lower opening 17A of the cylindrical body 17 is located below the upper opening 16A of the draft tube 16 and the cylindrical body 17 is supported via a mounting tool by the draft tube 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bubble column used in a reaction involving foaming and can be used in fermentation industry, petroleum industry and the like.

[0002]

BACKGROUND ART As shown in FIG. 4, in a bubble column 2 with a draft tube 1 used for a reaction (or treatment) involving foaming, a nozzle provided with gas at the bottom of the column. A circulating flow is generated in the reaction liquid 4 by blowing bubbles 3 into the reaction liquid 4 and raising the generated bubbles 5 while dispersing them in the draft tube 1.

In the above reaction, the bubbles generated on the liquid surface in the bubble column 2 contain a catalyst and a reaction product. Such bubbles block the line to the next step connected to the bubble column, or adhere to the wall surface of the bubble column 2,
This has been a cause of hindering driving and reducing productivity. Conventionally, in order to solve such a problem, the bubble column 2 is sized to cope with the generation of bubbles, or a method of artificially eliminating bubbles is adopted.

The defoaming method is roughly classified into a chemical method and a mechanical method. As the chemical method, for example,
There is a method of dropping the antifoaming agent from the upper part of the tank. However, according to such a method, it is necessary to continuously supply a constant amount of the antifoaming agent into the tank by the pump. Periodic cleaning of the tank and filling line is required, which makes maintenance and inspection troublesome. Further, in the case of the mechanical method, there are still problems of the apparatus itself, such as scale-up and development of a small and high-performance defoaming mechanism that can be attached to a large bubble column. Therefore, an object of the present invention is to provide a bubble column capable of suppressing the generation of bubbles.

[0005]

The bubble column according to the first aspect of the present invention is characterized by including a draft tube and a cylindrical body disposed near the upper opening of the draft tube. The tubular body promotes the separation of air bubbles from the reaction solution and suppresses foaming, which suppresses gas entrainment in the annulus (between the outside of the draft tube and the bubble column) and gas holdup ( This contributes to the reduction of the gas volume ratio in the gas-liquid mixed layer). And
It becomes possible to suppress excessive gas circulation and improve volume utilization efficiency.

The cylindrical body may have an open upper surface and a lower surface so that liquid or gas can pass through. The shape of the plane cross section is arbitrary, and examples thereof include a circle or a polygon such as a triangle, a quadrangle, and a hexagon. The vicinity of the upper end, for example, when the draft tube and the tubular body are both circular,
It means that the tubular bodies are concentrically arranged without contacting the draft tube.

The lower opening of the tubular body may be located at the same position as or above or below the upper opening of the draft tube. However, in order to smoothly introduce air bubbles from the draft tube, the lower opening of the draft tube is more than the upper opening. It is desirable to be located below. The specific length and diameter of the cylindrical body are appropriately set according to the physical properties of the reaction solution, the flow rate of gas, and the like. A bubble column according to a second aspect of the present invention is characterized in that the cylindrical body has a smaller diameter than the draft tube and is arranged so as to be located in an upper opening of the draft tube.

A bubble column according to a third aspect of the present invention is characterized in that, in the second aspect, the tubular body is a multiple tubular body having a diameter smaller than that of the draft tube. The multiple tubular body is, for example, a double tubular body including a first tubular body having a smaller diameter than the draft tube and a second tubular body having a smaller diameter than the first tubular body. And the size of the bubble tower,
A triple tubular body, a quadruple tubular body, or the like may be used depending on desired characteristics.

A bubble column according to a fourth aspect of the present invention is characterized in that the cylindrical body has a diameter larger than that of the draft tube and is arranged along an upper opening of the draft tube. Also in this case, as in the third invention, it is optional to make the tubular body a multiple tubular body such as a double tubular body. The type of the bubble column is arbitrary as long as it is used in a reaction or treatment involving foaming. For example, in addition to a bubble column, a stirring tank, and the like used in the fermentation industry, the petroleum industry, and the like, an aeration tank for wastewater treatment and the like are included.

[0010]

EXAMPLE A bubble column 11 according to a first example of the present invention will be described with reference to FIG. This bubble tower 11 is a cylindrical tower body 1
2. It comprises a gas supply pipe 13 connected to the bottom of the tower and a gas discharge pipe 14 connected to the top of the tower. A nozzle 15 is attached to the tip of the gas supply pipe 13. The tower body 12 is provided with a cylindrical draft tube 16 and a tubular body 17 arranged near the upper opening 16A of the draft tube 16.

The tubular body 17 is cylindrical and has a diameter smaller than that of the draft tube 16. Further, it is concentric with the draft tube 16 and is arranged so as to be positioned inside the upper opening 16A of the draft tube 16. In addition, the lower opening 17A of the draft tube 16
Is located below the upper opening 16A. This tubular body 17
Are supported by the draft tube 16 via fixtures not shown.

Next, the operation of the bubble column 11 during the reaction will be described. A predetermined amount of a predetermined reaction liquid 18 is contained in the tower body 12. Gas is fed into the tower body 12 from the gas supply pipe 13, and the gas discharged from the nozzle 15 becomes bubbles 19 and rises in the reaction liquid 18, and as the bubbles 19 rise, the gas in the reaction liquid 18 rises. To produce the desired circulating flow.

Then, the gas-rich reaction liquid containing a large amount of bubbles 19 flows out from the upper portion of the cylindrical body 17 and the cylindrical body 17
The flow-rectifying action is performed by flowing out the liquid-rich reaction liquid with a small amount of bubbles 19 from the lower part of the. In addition, the gas is
The excessive extraction of the gas dispersion energy is suppressed by preferentially extracting the gas from the upper part of the gas, thereby suppressing the generation of minute secondary bubbles. Since the minute bubbles have a small buoyancy, they are easily mixed with the circulating flow in the tank, which increases the gas hold-up and lowers the density of the annulus portion, thereby lowering the circulation performance.

According to the bubble column 11 of the above embodiment, the column body 12
Since it has a cylindrical body 17 disposed in the vicinity of the upper opening 16A of the draft tube 16, it promotes the separation of the bubbles 19 from the reaction liquid 18 and suppresses foaming, which is the annulus (the outside of the draft tube and the bubbles). Gas holdup can be reduced as a result of suppressing gas entrainment into the column). Further, since the tubular body 17 has a cylindrical shape and has a simple structure, it can be easily manufactured and attached.

Next, the bubble column 21 according to the second embodiment of the present invention will be described with reference to FIG. In the case of the first embodiment, the tower body
In the bubble column 21 of the present embodiment, although there is one tubular body 17 provided in 12, the cylindrical first tubular body 22 having a smaller diameter than the draft tube 16 and the tubular body 22 Second smaller diameter
The cylindrical body 23 of the draft tube 16 is the same as in the first embodiment.
It is arranged so as to be located in the upper opening 16A. The interval between the two tubular bodies 22 and 23 is arbitrary.

By thus forming the tubular bodies 22, 23 in a double structure, the best foaming can be achieved depending on the size of the bubble column 21, the size of the draft tube 16, the desired characteristics (gas flow rate), etc. The suppression effect will be obtained. Therefore, although the cylindrical bodies 22 and 23 of the second embodiment have a double structure, they may have a triple structure or more depending on the size of the bubble column and the like.

Next, a bubble column 31 according to a third embodiment of the present invention will be described with reference to FIG. The tubular body 32 of this embodiment is cylindrical and has a larger diameter than the draft tube 16. Further, it is concentric with the draft tube 16 and is arranged along the upper opening 16A of the draft tube 16. The lower opening 32A is located below the upper opening 16A of the draft tube 16. This tubular body 32
Is also supported by the draft tube 16 via a fixture (not shown).

In the case of the bubble column 31 of this embodiment, the bubbles 19 discharged from the draft tube 16 pass through the tubular body 32, and most of them are extracted from the top of the column, but some bubbles 19 are Body 12
After descending between the inner wall of the cylindrical body 32 and the cylindrical body 32, it rises through the lower opening 32A of the cylindrical body 32 to cause circulation of bubbles. As a result, the gas is less likely to be mixed with the circulation flow outside the draft tube 16 and gas holdup can be reduced.

Experimental Example 1 In the bubble column of the above-mentioned Example 1, the concrete dimensions of the cylindrical body 17, the gas supply rate, etc. were set as follows, and from the lower end of the draft tube 16 after the steady state was reached. The gas holdup at each measurement position (50 cm, 75 cm, 100 cm, 125 cm, 150 cm) was measured. The results are shown in Table 1.

Bubble column: 14 cm in diameter, 250 cm in height Draft tube: 7 cm in diameter, 120 cm in length Cylindrical body: 5 cm in diameter, 40 cm in length Position of cylindrical body: Lower opening is located 3 cm below upper opening of draft tube To do. Type of reaction solution: 1% butanol solution Amount of reaction solution: Position of liquid surface is from bottom of draft tube 14
0 cm gas supply rate: 1.8 cm / sec

[0021] Experimental Example 2 Experimental Example 2 and 3, each bubble column of Example 2 and 3
Corresponding to 21,31, the concrete dimensions of the cylindrical bodies 22, 23, 32 are as follows. Other conditions are Experimental Example 1
Is the same as. Then, the gas holdup was measured in the same manner as in Experimental Example 1. The results are shown in Table 1.

First (outer) tubular body of Experimental Example 2 ... Diameter 5
cm, length 8 cm Position of the first tubular body ... The lower opening is located 3 cm below the upper opening of the draft tube. Second (inner) tubular body of Experimental Example 2 ... Diameter 3.6 cm, length 40 c
m Position of the second tubular body ... The lower opening is located 3 cm below the upper opening of the draft tube. Cylindrical body of Experimental example 3 ... Diameter 10 cm, length 17 cm Position of tubular body of Experimental example 3 ... The lower opening is located 2 cm below the upper opening of the draft tube.

Comparative Example The gas holdup was measured in the same manner as in the experimental example for a conventional bubble column (see FIG. 4) having no tubular body. The conditions other than the dimensions of the draft tube are the same as in the experimental example. The results are shown in Table 1. Draft tube ... diameter 7 cm, length 160 cm

[0024]

[Table 1]

From Table 1, according to the bubble column according to the embodiment,
It can be seen that since the tubular body is arranged near the upper opening of the draft tube, the gas holdup of the annulus portion is small and foaming can be suppressed. On the other hand, according to the bubble column according to the comparative example, the gas holdup is large because the cylindrical body is not provided.

[0026]

According to the bubble column of the present invention, generation of bubbles can be suppressed.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a bubble column according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway front view of a bubble column according to a second embodiment of the present invention.

FIG. 3 is a partially cutaway front view of a bubble column according to a third embodiment of the present invention.

FIG. 4 is a partially cutaway front view of a bubble column according to a conventional example.

[Explanation of symbols]

 11,21,31 Bubble tower 12 Tower body 16 Draft tube 17,22,23,32 Cylindrical 18 Reaction liquid 19 Bubbles

Claims (4)

[Claims] 1. A bubble column comprising a draft tube and a tubular body arranged in the vicinity of an upper opening of the draft tube. 2. The bubble column according to claim 1, wherein the cylindrical body has a diameter smaller than that of the draft tube and is arranged so as to be located in an upper opening of the draft tube. 3. The bubble column according to claim 2, wherein the tubular body is a multiple tubular body having a diameter smaller than that of the draft tube. 4. The bubble column according to claim 1, wherein the cylindrical body has a diameter larger than that of the draft tube and is arranged along an upper opening of the draft tube.