JPH0240225A - Method and apparatus for generating small bubble in liquid - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention generates fine bubbles to introduce gas into a liquid at a ratio of gas to liquid that is higher than conventionally possible. Regarding equipment.

(Prior art and problems to be solved by the invention) In the chemical industry, many processing techniques are used to bring physically different material phases into close contact, which is necessary to obtain the desired chemical reaction in an optimal state. - In boat fishing, the above chemical reactions occur in the liquid phase, so various devices have been developed to disperse gas in the liquid.

In a typical gas-liquid reactor, gas is introduced into the bottom of the reactor through a standpipe with one end open, a perforated horizontal pipe perforated plate, or an annular porous sparge tube. In a normal gas flow range, the bubbles generated by the above means are relatively large, for example about 0.
．． Using pore sizes from 6 mm (1/4 inch) to 25 mm (1 inch), the bubble diameter is approximately 0.6 mm (1 inch).
/4 inch) to about 25 mm (1 inch).

Aspirators have also been used to disperse gases into liquids; in this type of device, the liquid is forced through a nozzle at a high flow rate, and the gas is drawn in, for example through a venturi, and dispersed into the liquid stream. However, in this type of device, the ratio of gas to liquid is generally small, for example approximately 1:
It is about 1 or less.

[Means to solve the problem]

Expressed in its simplest form, the invention provides for introducing a gas and a liquid through separate conduits and ejecting the gas and liquid simultaneously from mutually opposed orifices,
A method is provided for generating microbubbles in a liquid by ejecting the liquid at a velocity sufficient to create a localized shear field at the gas orifice. By the above method, it is possible to generate fine bubbles even at a large volumetric flow rate ratio of gas and liquid, that is, a gas-liquid volumetric flow rate ratio in the range of about 1=1 to 20:1 or more.

The present invention is naturally applicable to a wide range of processes that require intimate contact between a liquid phase and a gas phase, and in a particularly preferred embodiment of the present invention, a concentric A gas-liquid mixing device is provided in which jets of liquid and gas are separately ejected into the liquid in the mixing tank by annular dispersion tubes for liquid and gas installed in the mixing tank. Since the orifices provided in each of the dispersion tubes face each other, the liquid and gas ejected from the orifices generate a large shear field at the gas orifice, resulting in finer particles than when no shear field is generated. can generate bubbles.

Preferably, the liquid ejected from the liquid dispersion tube is used for circulation.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

〔Example〕

The accompanying drawings illustrate the principle of the invention, in which two fluids, one gas and one liquid, are passed through separate conduits each having an orifice opposite the other, and the liquid ejected from the liquid orifice is a gas. 1A and 1B illustrate various configurations of bubble generators based on the principle of generating a localized shear field at an orifice to generate uniformly sized bubbles in a surrounding liquid.

FIG. 1 shows conduits 12 and 14, each having an open end, disposed in a contactor or reactor. As shown, orifices 15 and 16 of conduits 12 and 14 are opposed to each other so that a local shear field is generated at the orifices. Therefore, the orifices are generally opposed to each other at an angle of approximately 20° to 160°.

Preferably, the orifices are arranged on the same plane and are opposed to each other at an angle of 90°.

Since the above conduit is located near the bottom of the liquid phase, conduit 1
The gas introduced into the liquid phase through 2 moves upwards in the liquid phase. Further, although not shown, there is provided a means for pumping gas through the conduit 12 and ejecting it from the orifice 15, and similarly liquid is passed through the conduit 14 and ejected from the orifice 16.
Means is provided for pumping the liquid so that it is ejected from the liquid. The liquid introduced through conduit 14 may be of the same type as the surrounding liquid, or it may be of a different type. Usually, the orifice provided in the above-mentioned conduit has an approximate diameter of 3 mm (1/8 inch).
The size is about 100 mm (4 inches).

Although the flow rate of gas and liquid in the conduit can be adjusted using valves, pumps or similar means, it is important that the liquid flow at a velocity sufficient to create a local shear field at the gas orifice. The purpose is to cause the gas to be ejected from the orifice of the conduit, thereby generating finer bubbles when the gas is released from the orifice of the conduit than if the local shear field were not generated. - For boat fishing, the liquid is ejected from the liquid orifice at a speed in the range of approximately 3 m/sec (10 ft/sec) to greater than 9 m/sec (30 ft/sec), and the gas is The flow rate is set so that the jetting velocity from the gas orifice is approximately 1.5 m 7 seconds (5 feet/second) to 30 m/second (100 feet/second). In a fairly standard process operation, liquid is ejected from the liquid orifice at a rate of approximately 6 m/s (20 ft/s) and gas is ejected from the gas orifice at a rate of approximately 23 m/s (75 m/s).
It is ejected at a speed of 1 ft/sec).

In some instances, it is preferred that the gas orifice be much larger than the liquid orifice, for example, the ratio of the open area of the gas orifice to the liquid orifice is approximately 1.
; It can be set in a range of about 1 to 5:1. Second
The figure specifically shows the above-mentioned case, in which the gas and liquid conduits 22 and 24 have a rectangular cross section, respectively. The orifice in the embodiment of FIG. 2 is similarly rectangular in shape, with the gas orifice having a much larger open area than the orifice of the liquid conduit 24 as shown. Also, it goes without saying that both conduits are arranged on the same plane and at right angles.

By increasing the opening area of the gas orifice,
It is possible to release gas into the liquid at a lower rate and still set the gas flow rate to be greater than the flow rate of the liquid being released from conduit 24.

In the embodiment shown in FIG. 3, two concentric annular pipes 32 and 34 have a plurality of orifices 36 and 38, respectively.
and is provided. As shown in the figure, the orifices are arranged at right angles to each other in mutually aligned positions, and in the figure, the annular pipe 32 is for gas and the annular pipe 34 is for liquid.

FIG. 4 shows annular dispersion tubes 42 and 44 disposed at the bottom of a liquid column in a contactor or reactor having a cylindrical side wall 10.
The figure shows the following. In the figure, orifice 46 and dispersion tube 42 are positioned relative to orifice 48 and dispersion tube 44 such that orifices 46 and 48 are perpendicular to each other in an aligned position. In this case, the liquid is forced through the dispersion tube 44 and ejected from the orifice 48 at a velocity sufficient to shear the gas emitted from the dispersion tube 42, thereby generating uniform microbubbles.

As shown in FIG. 4, the conduit 47 and the annular dispersion pipe 44 communicate with each other via distribution pipes 45 extending radially from the conduit 47. In a particularly preferred embodiment, said orifice 4
Liquid in the vessel is allowed to circulate through conduit 47 in order to impart shear to the gas ejected from 6. Similarly, means are provided for distributing the gas to the annular distribution tube 42, such as a distribution tube 49.

In a particularly preferred embodiment of the invention, the annular bubble dispersion tube is placed in a bubble column or the like.

Experimental results demonstrating the excellent effects of the present invention will be described below.

In this experiment, approximately 90On+m (3
ft) diameter tank was used. This tank is equipped with a device for circulating water and is further provided with two concentric annular pipes at the bottom of the tank for introducing gas and liquid respectively. The outer ring pipe of the above ring pipe has a height of approximately 13 m for introducing gas into the tank.
An inwardly directed slot approximately 1/2 inch (311 Im) wide and 1/8 inch (311 Im) wide, while the inner annular tubing has an approximately 6 in.
A slot approximately 3 mm (1/8 inch) wide is arranged perpendicular to the gas slot. In this experiment, the gas was passed through the gas annular pipe for approximately 4. ONn+"/min (1505 cF/min) and the liquid flows through the liquid ring pipe from about 0.19 m'/min (50 gal/min) to about 0.38 m
3/min (100 gallons/min), respectively;
After the gas and liquid were introduced and a steady state was reached, the supply of gas and liquid was stopped. At the same time as the supply was stopped, a video recorder recorded the drop in the water level in the tank, and the drop in water level was analyzed as a function of time using standard methods to estimate the bubble size distribution. Furthermore, the average amount of gas retained in the tank during the experiment was determined from the water level in the steady state. Furthermore, comparative data was obtained by reproducing the above process without using a sheared liquid flow, and it was found that by using the bubble generator according to the present invention, the bubble size was 0.4.
It was confirmed that the size decreased from 2 mm to 0.34 mm, and the average gas retention amount increased from 24.8% to 29.6%.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a bubble generator according to the present invention, FIG. 2 is a schematic diagram showing another form of the bubble generator according to the present invention, and FIG. 3 is a double ring disperser type bubble generator according to the present invention. FIG. 4 is a partial perspective view schematically illustrating a cross-section of the device; FIG. 4 is a cross-sectional view of an embodiment of the invention using a double-ring distributor with means for circulating the liquid in the vicinity of the liquid distributor; 14, 22.32... Conduit for gas, 12, 24.34... Conduit for liquid, 15, 36.46... Orifice for gas, 16, 38
．． 48... Orifice for liquid, 42... Annular dispersion tube for gas, 44... Annular dispersion tube for liquid, 45... Distribution pipe for liquid, 49... Distribution pipe for gas. FIG.3

Claims (1)

[Claims] 1. By ejecting gas from an orifice provided in the liquid and at the same time ejecting the liquid from another orifice opposite the orifice at a velocity sufficient to generate a local shear field, A method of generating microbubbles in a liquid that consists of generating air bubbles. 2. The ejection velocity of the liquid ranges from about 3 m/sec (about 10 ft/sec) to greater than about 9 m/sec (about 30 ft/sec), and the gas ejection velocity is about 1.5 m/sec.
/second (approximately 5 feet/second) to approximately 30m/second (approximately 100 feet/second)
2. The method of claim 1, wherein the method is ft/sec). 3. The method of claim 1, wherein the volumetric flow ratio of gas and liquid ejected from each orifice ranges from about 1:1 to greater than about 20:1. 4. In a method for promoting gas-liquid contact by spouting gas from an orifice provided in a gas distributor into a liquid, another orifice facing the orifice from which the gas is jetted forms an angle of about 20° to 160°. An improved method comprising ejecting liquid from an orifice at a velocity sufficient to shear the ejected gas from said gas distributor, thereby producing finer bubbles than would be the case without said shearing. 5. The improved method according to claim 4, wherein the ejection velocity of the liquid is in the range of about 3 m/sec (about 10 ft/sec) to greater than about 9 m/sec (about 30 ft/sec). . 6. The improved method according to claim 5, wherein the ejection velocity of the gas is about 1.5 m/sec (about 5 ft/sec) to about 30 m/sec (about 100 ft/sec). 7. The improved method of claim 4, wherein the volumetric flow ratio of gas to liquid ejected from the orifice ranges from about 1:1 to about 20:1. 8. A container containing a liquid; A gas conduit provided with a gas orifice and disposed within the container such that the gas orifice is located in the liquid under use conditions; Outline of the gas orifice a liquid conduit comprising a liquid orifice located on the same plane and facing the gas orifice at an angle of about 20° to 160°; means for ejecting; ejecting a liquid through the liquid orifice at a velocity sufficient to shear the gas ejected from the gas orifice, thereby generating microbubbles that contact the liquid in the container; A gas-liquid contact device comprising means for floating while 9. Claim 8, wherein the liquid orifice faces the gas orifice at an angle of 90°.
The equipment described in section. 10. The apparatus according to claim 9, wherein the gas conduit is an annular dispersion tube, and the liquid conduit is an annular dispersion tube disposed concentrically with the gas annular dispersion tube.