JPH03242297A - Fine bubble generating and diffusing device - Google Patents

Abstract

PURPOSE:To obtain the fine bubble generating and diffusing device which increases the transfer efficiency of gas into liquid by providing hollow members consisting of a porous material into a reaction chamber and connecting the hollow parts to a compressed gas generating means. CONSTITUTION:Compressed gas flows first from a ventilation chamber 6 into an air accumulation chamber 1 when the compressed air is supplied to the ventilation chamber 6 while the air accumulation chamber 1 is kept rotated. This air is released in the form of bubbles from the surfaces of the hollow porous fibers 8 into culture soln. in a culture tank 2. Since the air accumulation chamber 1 is under rotation at this time, the surfaces of the hollow porous fibers 8 move relatively with the culture soln. The bubbles coming onto the surfaces of the hollow porous fibers 8 are forcibly separated by the centrifugal force, etc., of this time and are released as the small bubbles into the culture soln. The min. diameter of the bubbles released into the soln. from the air diffuser can be made into about several +mum unit and the transfer efficiency of the gas into the liquid is increased.

Description

[Detailed Description of the Invention] C. Industrial Application Field] The present invention relates to a microbubble generating aeration device that supplies microbubble such as air into a liquid phase in a reaction tank such as a fermentation tank or a water treatment tank. It is related to.

[Conventional technology]

It is necessary to supply a sufficient amount of oxygen necessary for the metabolism of microorganisms to the culture solution in a reaction tank such as a fermenter, and for this purpose,
Aeration is often performed using a diffuser tube (superjar). Diffusion tubes can be roughly divided into two types: those with a diameter of several tens to hundreds of micrometers, and those with a diameter of 100 μm.The former uses porous materials, and the latter uses perforated or A nozzle is used.

For the purpose of supplying oxygen into the culture solution, it is better that the bubbles generated from the aeration tube be smaller if the amount of gas supplied is the same.

This is because, if the total volume of the bubbles is the same, the smaller the volume of one bubble, the larger the bubble interface area and the higher the oxygen transfer efficiency.

However, if a diffuser tube with a small hole diameter is used to emit small air bubbles, clogging tends to occur, so normally a diffuser tube with a hole diameter of 100 mm is used, and a diffuser tube is installed directly above the diffuser tube for air bubble breakup. A stirring impeller is installed.

[Problem to be solved by the invention]

A recent trend in fermentation processes is culture using high bacterial cell densities. If the amount of bacterial cells is increased, the amount of oxygen supplied must also be increased accordingly, and methods such as increasing the rotational speed of the stirring impeller have been taken.

However, when the rotation speed of the impeller is increased to several hundred r, p, m or more, (1) bacterial cells are likely to be damaged due to high shear stress;
2) There are problems such as high energy costs, and it is desired to develop a diffuser tube that generates fine bubbles without dividing the impeller.

The present invention was developed in consideration of the above-mentioned problems, and compared to the conventional air diffuser in which the diameter of bubbles that come out is at least several hundred micrometers, the present invention allows bubbles with a minimum diameter of several tens of micrometers to be produced. An object of the present invention is to provide a fine bubble generation aeration device which can perform aeration to increase the transfer efficiency of gas into a liquid and can also be applied to a solid-liquid flotation separation device. It is.

[Means to solve the problem]

In order to achieve the above object, the micro bubble generation diffuser according to the present invention includes a hollow member made of a porous material provided in a reaction tank rotatably and connected to a rotational drive means, and The section is connected to compressed gas generating means.

In addition, a hollow gas storage chamber is provided in the reaction tank so as to be rotatable and connected to the rotation driving means, and a hollow gas storage chamber is provided in the reaction tank and connected to the compressed gas generation means, and the outer circumference of the gas storage chamber is connected to the compressed gas generation means. , a hollow member made of a porous material is attached with its hollow portion communicating with the air storage chamber.

The hollow member attached to the outer periphery of the air storage chamber is a hollow porous fiber.

Further, an air storage chamber made of a porous material is rotatably provided in the reaction tank and connected to the rotation drive means, and the hollow portion thereof is connected to the compressed gas generation means.

Further, the pore diameter of each of the above porous materials is several μm or less.

[For production]

By rotating the hollow member while supplying compressed gas to the hollow part of the hollow member, air bubbles generated on the surface of the hollow member are forcibly separated by centrifugal force, etc., and become small air bubbles that enter the liquid in the reaction tank. released.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a first embodiment of the present invention. In the figure, 1 is a cylindrical air storage chamber with closed upper and lower ends, and this air storage chamber 1 is supported by a support provided on the bottom plate 3 of the culture tank 2. It is rotatably supported by a stand 4 and provided inside the culture tank 2. The support base 4 is provided with a ventilation chamber 6 to which a ventilation pipe 5 is connected, and this ventilation chamber 6 is connected to the hollow portion of the air storage chamber 1 through a ventilation hole 7.

A plurality of hollow porous fibers 8 are fixed to the outer periphery of the air storage chamber 1 in parallel with the rotation axis of the air storage chamber 1, respectively. One end of each hollow porous fiber 8 is put into the storage chamber 1 and left open, and the other end is closed.

A net 9 for protecting the hollow porous fibers 8 is fixed to the bottom plate 3 of the culture tank 2 on the outside of the air storage chamber 1.

A rotating shaft 1a passing through the support base 4 is connected to the axial center of the bottom of the air storage chamber 1, and a rotation drive unit (not shown) is connected to this rotating shaft 1a.

The hollow porous fiber 8 has a pore diameter of about 0.1 μm. This hollow porous fiber 8 has both ends connected to the storage air 1.
It may be opened inward. Note that the entire length of the hollow porous fiber 8 does not necessarily need to be fixed to the outer surface of the air storage chamber 1, and only its both ends may be fixed. 10.11 is a seal ring.

In this embodiment, the ventilation chamber 6 is rotated while the air storage chamber 1 is rotated.
When compressed air is supplied to the storage chamber 1 , the compressed air first flows from the ventilation chamber 6 to the storage chamber 1 , and this air becomes bubbles from the surface of the hollow porous fiber 8 and is released into the culture solution of the culture tank 2 . At this time, since the pressure accumulator 1 is rotating, the surface of the hollow porous fiber 8 moves relative to the culture solution, and the air bubbles that come out on the surface of the hollow porous fiber 8 are caused by centrifugal force etc. at this time. They are forcibly peeled off and released into the culture medium in the form of small bubbles.

The diameter of the pressure accumulating chamber 1 in the above embodiment is about 10 cm, the rotation speed thereof is about 10 Or+p+Ifl+compressed air pressure is about 1 to 5 atm.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, the same members as those in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted.

The air storage chamber 1', which is rotatably supported on the support base 4, is made of an unglazed filter material with a pore diameter of several hundred μm, and the hollow part of this material is connected to the ventilation chamber 6 of the support base 4 through a ventilation hole 7. ’ is continued.

In this configuration, the ventilation chamber 6 is rotated while the air storage chamber 1' is rotated.
When compressed air is supplied to the pressure storage chamber 1' from the ventilation chamber 6,
Compressed air flows into the pressure storage chamber 1', and this air becomes bubbles from the surface of the pressure accumulating chamber 1' and is released into the culture solution in the culture tank 2.

At this time, since the air storage chamber 1' is rotating, the air storage chamber 1'
The air bubbles that have appeared on the surface are forcibly separated by centrifugal force, etc., and are released into the culture medium as small air bubbles.

In addition, in this second embodiment, since the air storage chamber 1' is made of an unglazed filter material, the pore diameter of this is larger than that of the hollow porous fiber 8, and therefore, compared to the first embodiment described above. It has the advantage of low pressure loss and low power cost for the near compressor required for aeration, but it has the disadvantage of being easily clogged.

Therefore, when aerating a highly concentrated culture solution or a solution that contains solids or high concentrations, it is better to use an ultrafiltration membrane (pore size 5 to 0.01 μm) instead of an unglazed filter material. . In this case as well, the above-mentioned ultra 3 membrane is moved relative to the liquid, such as by swinging.

Air permeability is important for the porous material constituting the air storage chambers 1, 1', and metals, ceramics, polymeric materials, etc. are used as the material itself.

〔Effect of the invention〕

According to the present invention, the minimum bubble diameter of the bubbles released into the culture solution from the air diffuser can be set to several tens of micrometers, and the efficiency of gas movement into the liquid can be increased. Furthermore, since the diameter of the bubbles released into the liquid can be made small, this device can also be applied to a solid-liquid flotation separation device. In particular, according to the present invention, since the culture solution is not stirred, the bacterial cells in the culture solution are not damaged. Further, the energy required for the rotational drive means is small because the rotating body is formed into a cylindrical shape, and the energy cost can be reduced.

[Brief explanation of drawings]

FIGS. 1 and 2 are partially cutaway sectional views showing different embodiments of the present invention. 1.1' is an air storage chamber, 2 is a culture tank, 8 is a hollow porous fiber, and 1a is a rotating shaft.

Claims (5)

[Claims] (1) Micro-bubble generation characterized in that a hollow member made of a porous material is rotatably provided in the reaction tank and connected to a rotational drive means, and the hollow part is connected to a compressed gas generation means. Air diffuser. (2) A hollow gas storage chamber 1 is provided in the reaction tank so as to be rotatable and connected to a rotation driving means, and this gas storage chamber 1 is connected to a compressed gas generation means, and this gas storage chamber 1 is connected to a compressed gas generation means. 1. A microbubble generating air diffuser, characterized in that a hollow member made of a porous material is attached to the outer periphery of the apparatus, with the hollow part communicating with an air storage chamber. (3) The micro-bubble generating air diffuser according to claim (2), wherein the hollow member attached to the outer periphery of the air storage chamber 1 is a hollow porous fiber. (4) An air storage chamber 1' made of a porous material is rotatably provided in the reaction tank and connected to a rotation driving means, and
A fine bubble generation/diffusing device characterized in that the hollow part is connected to compressed gas generation means. (5) The micro-bubble generating/diffusing device according to any of claims (1), (2), (3) and (4), wherein the porous material has a pore diameter of several μm or less.