KR20030045321A - A Micro-Bubble Generator And Liquid Treatments Using The Micro-Bubble Generator - Google Patents

Abstract

PURPOSE: An ultra-fine bubble producing device for waste water treatment and a method for treating liquid using the same are provided, thereby staying the bubbles produced in waste water for a long time and easily dissolving the bubbles in waste water due to its increased surface area. CONSTITUTION: An ultra-fine bubble producing device for waste water treatment comprises an inlet(24) through which gas-containing liquid is introduced; a waste water-inducing member(22) providing a pathway for introduced liquid; a collision plate(16) with which liquid passed through the waste water-inducing member(22) is collided to form ultra-fine bubbles; and an outlet(26) through which ultra-fine bubble-containing liquid is discharged.

Description

A micro-bubble generator and liquid treatments using the micro-bubble generator}

The present invention relates to an ultra-foam bubble generator for wastewater treatment, and more particularly, to induce a liquid flowing into the ultra-foam bubble generator to collide with a wall and dissolve gas in the wastewater using the ultra-bubbles generated by the collision. It relates to an ultra-fine bubble generator.

The activated sludge method generally used in biological wastewater treatment is to decompose organic matter by various microorganisms, and it is necessary to supply oxygen as its operating condition, and the treatment efficiency is directly related to the transfer efficiency of oxygen. The higher the processing efficiency.

Typically, oxygen consumed by the activated sludge method is supplied by an acid device such as an acid engine, a bubble acid engine or a microbubble acid engine, or a mechanical aeration device such as a simplex or surface stirring method.

By the way, the oxygen supply method using an acid device uses a method of injecting air into the bubble acid engine or the micro-bubble acid engine by using a separate pump for supplying air, and thus requires a lot of power. By maintaining the size of the bubble discharged through the hole provided in the size of about 2 to 10mm, the contact area between the bubble and the wastewater is small, and the residence time for sufficiently dissolving oxygen in the wastewater is insufficient. Particularly, in the ozone injection process, the existing ceramic microbubble diffuser has a generated ozone bubble diameter of 2 to 10 mm, and the rising speed of the bubble is 24 cm / sec, so that the residence time of ozone in the wastewater is about 20 to 30 minutes. to be. Therefore, it is necessary to provide an ozone recovery facility to recover ozone that has not been dissolved into waste water.

In the case of the mechanical aeration device, it is difficult to transfer oxygen to the deep part of the wastewater to be treated because physically agitating the wastewater stored in the reservoir to dissolve the oxygen contained in the atmosphere.

The present invention has been made to solve the above problems, by mixing the gas into the wastewater flowing into the bubble generator, the gas is mixed by inducing the wastewater mixed with the impingement plate inside the bubble generator to generate fine bubbles The technical problem is to make it easy to dissolve in waste water.

1 is a cross-sectional view of the ultra-fine bubble generator according to the present invention,

2 is a block diagram of a liquid treatment method including an ultra-fine bubble generator for improving the dissolved oxygen or dispersion efficiency of wastewater according to the present invention,

3 is a view showing the dissolved oxygen concentration change according to the use time of the ultra-fine bubble generator according to the present invention,

Figure 4 is a flow chart of the material balance of the ultra-fine bubble generator according to the present invention,

5 is a view showing a material transfer coefficient (K _La ) according to the wastewater flow rate of the ultra-fine bubble generator according to the present invention,

6 is a view showing a material transfer coefficient (K _La ) according to the liquid / gas ratio of the ultra-fine bubble generator according to the present invention,

7 is a view showing a standard aeration efficiency (SAE) according to the back pressure of the ultra-fine bubble generator according to the present invention,

8 is a view showing a standard aeration efficiency (SAE) according to the liquid / gas ratio of the ultra-fine bubble generator according to the present invention,

<Description of Symbols for Main Parts of Drawing>

2: Pump 4: Injector

6: ultra-fine bubble generator 8: the first pressure gauge

8 ': second pressure gauge 10: back pressure regulating valve

12: gas storage tank 14: reservoir

16: crash plate 18: Flange

20: baffle plate 22: wastewater induction member

24: inlet 26: outlet

28: drain

The ultra-foam bubble generating device of the present invention is an inlet for gas-liquid inflow, wastewater inducing member providing a path of the inflowing liquid, the impingement plate collides with the liquid passing through the wastewater inducing member to form an ultra-fine bubble And an outlet through which the liquid containing the micro bubbles is discharged.

In addition, the liquid treatment method using the ultra-fine bubble generating device according to the present invention is connected to the reservoir and the reservoir to store the liquid to be treated, the pump to suck and discharge the liquid stored in the reservoir, discharged from the pump An injector through which liquid passes and a target gas to be dissolved into a liquid is mixed into a liquid, and an ultra-fine liquid that is connected to one side of the injector to produce a liquid containing the target gas discharged from the injector into a liquid containing ultra-fine bubbles It is characterized by consisting of a bubble generator and a back pressure control valve for adjusting the ratio of liquid and gas.

Hereinafter, with reference to the accompanying drawings will be described in more detail with respect to the ultra-fine bubble generator and the liquid treatment method according to the present invention. Here, the liquid is a target fluid to disperse gas, and generally refers to industrial wastewater, domestic wastewater, sewage, river water and domestic sewage. However, in the following detailed description, only the wastewater will be described.

1 is a cross-sectional view of an ultra-fine bubble generator according to the present invention, Figure 2 will be described together with the configuration of a liquid treatment method including an ultra-fine bubble generator for improving the dissolved or dispersed efficiency of the gas according to the present invention.

As shown in FIG. 1, the ultra-foam bubble generator 6 is connected to the inlet 24 through which the wastewater containing gas is introduced, and the wastewater induction that leads the wastewater to the impingement plate 16. Member 22, impingement plate 16 for producing ultra-fine bubbles by colliding with the wastewater discharged from wastewater-inducing member 22, baffle plate provided on one side of the upper and one side of the ultra-fine bubble generator 6, respectively (20), a discharge port 26 for discharging the wastewater filled with bubbles having passed through the obstruction plate 20, a drain hole for discharging the wastewater inside the ultra-fine bubble generator (6) to the outside if necessary ( 28) and a flange 18 for facilitating assembly or cleaning of the device.

Referring to the operation principle of the ultra-fine bubble generator 6 having the configuration as described above are as follows.

First, the wastewater containing gas is introduced into the ultra-fine bubble generator 6 through the inlet 24, and the wastewater introduced is the ultra-foam bubble generator 6 through the wastewater guide member 22. It penetrates the center and leads to the top. On the other hand, the horizontal surface of the impingement plate 16 is located perpendicular to the wastewater inducing member 22 at a predetermined distance from the end of the wastewater inducing member 22 to the inner side of the upper end of the ultra-fine bubble generator 6, the wastewater induction The high pressure wastewater discharged from the end of the member 22 collides with the collision plate 16 at high speed to generate ultra-fine bubbles. Ultra-foam bubbles generated in this way flows to the lower end of the ultra-fine bubble generator 6 through the obstruction plate 20, the obstruction plate 20 is generated by delaying the flow of the liquid descending by gravity The super bubbles are easily dispersed into the liquid, and serve to promote the contact between the gas and the liquid. Therefore, the baffle plate is provided with a circular hole having a diameter of 0.3 to 0.7 cm around the waste water guide member 22 at intervals of 1 to 2 cm to hinder the flow of liquid. On the other hand, the waste water containing the ultra-fine bubbles passed through the obstruction plate 20 is discharged to the outside through the discharge port 26 provided on one side of the lower end of the ultra-fine bubble generator (6).

The size of the ultra-fine bubbles produced by the above-described method is 0.03 to 0.2mm and the ascending speed is about 0.1 to 0.8cm / sec, which is very small compared to the particle size of 2 to 10mm shown in the conventional diffuser. These include the physical advantages of long-term stay in the liquid phase and the advantages of providing a large surface area.

On the other hand, the ultra-fine bubble generator 6 is connected to a series of additional devices to improve the dissolved oxygen or dispersion efficiency of the waste water, this waste water treatment method will be described as follows.

As shown in FIG. 2, the wastewater treatment method including the ultra-fine bubble generator 6 is connected to one side of the reservoir 14 and the reservoir 14 in which the wastewater is stored, and injects the wastewater stored therein. Pump 1 to be transported to the second, the first pressure gauge (8) for measuring the pressure between the pump (2) and the injector (4), connected to the injector (4) passed through the first pressure gauge (8) When the gas passes through the injector (4), the gas storage tank 12 for supplying gas to the injector (4), the waste water discharged from the injector (4) is introduced to produce an ultra-fine bubble generator ( 6), it is composed of a back pressure control valve 10 for controlling the waste water discharged from the ultra-fine bubble generator 6 to adjust the mixing ratio of gas and waste water. Here, the second pressure gauge 8 'may be installed between the back pressure regulating valve 10 and the ultra-fine bubble generator 6 to adjust the discharge pressure.

On the other hand, when actually operating the system is to control the pressure of the wastewater flowing into and out of the ultra-fine bubble generator 6 by the back pressure control valve 10, by adjusting the back pressure control valve (10) The pressure of the wastewater flowing into the bubble generator 6 may be maintained at 2 to 5 kg _f / cm ² , and the discharged pressure may be about 1 to 4 kg _f / cm ² .

In the wastewater treatment method configured as described above, the wastewater discharged from the reservoir 14 in which the wastewater to be treated is stored is supplied to the injector 4 using the pump 2. At this time, the path through which the wastewater formed in the injector 4 passes decreases in size and increases. Accordingly, the wastewater pressure in the injector 4 decreases and increases. Therefore, the gas storage tank 12 is installed due to the pressure difference between the gas storage tank 12 and the injector 4 by installing a pipe connected to the gas storage tank 12 at the boundary point where the diameter of the injector 4 decreases and increases. The gas stored in the tank is moved to the injector 4. The gas thus moved is mixed with the wastewater passing through the injector 4, and the mixed wastewater flows into the ultra-foam bubble generator 6 to contain ultra-foam bubbles.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. However, the following examples are illustrative of the present invention, and the content of the present invention is not limited by the examples.

3 is a view showing the dissolved oxygen change according to the use time of the ultra-fine bubble generator according to the present invention, Figure 4 is a flow chart of the material balance of the ultra-fine bubble generator according to the present invention, Figure 5 is an ultrafine according to the present invention diagram showing the mass transfer coefficient (K _La) of the flow rate of the waste water in the bubbling device, Figure 6 is a view showing the mass transfer coefficient (K _La) of the liquid / period ratio of the second micro-bubble generating device according to the invention, 7 is a view showing a standard aeration efficiency (SAE) according to the back pressure of the ultra-fine bubble generator according to the present invention, Figure 8 is a standard aeration efficiency (SAE) according to the liquid / air ratio of the ultra-fine bubble generator according to the present invention It will be described together with a diagram showing).

<Example 1>

Preparation of ultra fine bubbles.

According to FIG. 1, an experimental apparatus for improving oxygen dissolution efficiency using an ultrafine bubble generator according to the present invention was manufactured.

The size of the ultra bubble generator is 42cm, the fluid flowing into the ultra bubble generator is water, the inlet pressure is 3.5kg _f / cm ² and the pressure of the outflow fluid is 2kg _f / cm ² The storage tank 12 is filled with air.

After only a series of batch cycles in the ultra-bubble generator 6 the water reached a supersaturation state. The result is shown in FIG.

Figure 3 shows the dissolved oxygen change according to the use time of the ultra-fine bubble generator, it shows that dissolved oxygen reaches a supersaturation state of 9mg / ℓ after 3 minutes of operation of the ultra-bubble generator as shown have.

Comparative Example

Based on the results obtained in Example 1, comparison was made with the behavior of a conventional diffuser.

Figure 4 is a flow chart of the material balance of the ultra-fine bubble generating apparatus according to the present invention, a variety of variables defined as follows, that is, the mass transfer coefficient (K _La ), Standard Oxygen Transfer Efficiency (SOTE), standard Standard Aeration Efficiency (SAE) was calculated to compare the above-mentioned variables in the behavior of conventional diffusers and the behavior of the ultra-foaming device of the present invention. The comparison results are shown in Table 1.

here,

K _La : mass transfer coefficient,

K _{La, 20} : Standard condition (atm, 20 ℃) Mass Transfer Coefficient,

C _m ^* : Arithmetic mean dissolved oxygen concentration (mg / ℓ)

C ₀ : Initial dissolved oxygen concentration (mg / ℓ)

C _s ^* : Saturated dissolved oxygen concentration in experimental conditions (mg / ℓ)

Q _air : Air flow rate under experimental conditions (mL / min)

V: reactor volume (ℓ)

Q _water : Flow rate under experimental conditions (L / min)

P1, P2: gauge pressure, (kg _f / cm ² )

T: Temperature (℃)

SOTE: Standard oxygen transfer efficiency (-)

SAE: Standard Aeration Efficiency (mg / kwh)

ρ: air density (0.9705 mg / ml)

W _O2 : oxygen supply rate (mg / min)

V _A : Volume of the aerated fluid (ℓ)

PP: Pump Power (kw)

PP = Q _water ΔP

ΔP: Pressure difference (kg _f / cm ² )

Energy efficiency: η = 75%

Total Power Consumption: PP / η

SAE = 296 η K _La C _m ^* / ΔP.

Comparison table of existing diffuser and ultra-fine bubble generator according to the present invention Diffuser type Mass transfer coefficient Standard Oxygen Transfer Efficiency (%) Standard Aeration Efficiency (kg / kwh) Micro Bubble Device <15 44 5.2 Bubble acid engine <15 <18 <3.1 Mechanical aeration <10 <10 <2.0 The present invention 81.2 60.9 6.5

Through the following examples using the ultra-fine bubble generator of the present invention to obtain the optimum operating conditions by deriving the material transfer characteristic value defined above.

<Example 2>

Influence of Wastewater Flow Rate and Liquid / Air Ratio on Microbubble Generators.

The ultra-bubble bubble generator was tested in the same configuration and conditions as in Example 1, but the pressure of the incoming fluid was ² kg / cm ² instead of 3.5 kg / cm ² , and the flow rate of the incoming water was 8-18 L / min.

The results are shown in FIGS. 5 and 6.

5 and 6 show the effects of wastewater flow rate and liquid / gas ratio on each mass transfer coefficient, and obtain a mass transfer coefficient while changing the liquid / gas ratio and wastewater flow rate. At this time, the liquid / gas ratio is a volume ratio of the liquid and gas, for example, if the liquid / gas ratio of 10 means that the volume of the liquid per gas volume of 10. On the other hand, the fluid used in the experiment was water, and when the flow rate of the incoming water increased from 8ℓ / min to 18ℓ / min, the mass transfer coefficient increased from 1.5 to 2.0, and when the liquid / gas ratio increased from 10 to 40, the mass progress coefficient It can be seen that decreases from 1.5 to 0.5. In particular, it was found that the mass transfer coefficient was significantly reduced with the liquid / base ratio of 20. Therefore, when the liquid / air ratio changes, the size of the bubble is affected, and thus the liquid / gas ratio has a large influence on the material transfer coefficient.

<Example 3>

Standard Aeration Efficiency and Standard Oxygen Transfer Efficiency.

Ultrafine bubble generator was carried out in the same configuration and conditions as in Example 2, but the flow rate of the incoming fluid was maintained at 17 L / min.

The results are shown in FIGS. 7 to 8.

As shown, it can be seen that the back pressure and the liquid / air ratio for the standard aeration efficiency exhibit similar behavior for the standard oxygen transfer efficiency in a wide range. That is, in FIG. 7, as the back pressure increased from 0.5 to 2.5 kg _f / cm ² , the standard aeration efficiency was changed to 4 to 10 kg _f O ₂ / kwh.

Meanwhile, in FIG. 8, the standard aeration efficiency was found to be a low value of 0.05 kg _{f 2} / kwh at a liquid / air ratio of 20 or more.

Therefore, the optimum operating conditions of the ultra-fine bubble generator for the present invention was as shown in Table 2.

Optimal Operation Conditions of Ultra-fine Bubble Generator Properties Operation condition Mass transfer coefficient 2.0 min ^-1 Standard Aeration Efficiency 9.2 Kg O ² / kwh Standard Oxygen Transfer Efficiency > 90%

As described above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the experimental examples and examples described above are illustrative in all respects and should be understood as not limiting. The scope of the present invention should be construed that all changes or modifications derived from the meaning and scope of the appended claims and their equivalents, rather than the detailed description, are included in the scope of the present invention.

The ultra-foam bubble generator of the present invention generates ultra-foam bubbles by colliding the wastewater mixed with gas on the impingement plate, and the ultra-foam bubbles have a longer stay in the wastewater than the bubbles produced by the conventional bubble generator. In addition to being able to be dissolved in the waste water, the contact area is large.

Claims (5)

An inlet 24 through which a liquid containing gas enters, a wastewater guide member 22 providing a path of the inflowed liquid, and a collision plate that collides with the liquid passing through the wastewater guide member 22 to form ultra-fine bubbles. And an outlet 26 through which the liquid containing the micro bubbles is discharged. The method of claim 1, Position and / or outlet 26 of a baffle plate 20 lower than the position of the outlet of the wastewater inducing member 22 to allow the ultra-fine foam to easily dissolve into the fluid. Ultra-fine bubble generator, characterized in that it further comprises at a position higher than the position of each. The reservoir 14, the pump 2 connected to the reservoir 14 to suck the liquid stored in the reservoir 14, and the liquid discharged from the pump 2 are stored. An injector 4 which passes through and injects a target gas to be dissolved into a liquid, is connected to one side of the injector 4, and sucks a liquid containing the target gas discharged from the injector 4 to form an ultra-fine bubble. An ultra-fine bubble generator (6) for producing a liquid containing the liquid processing apparatus using an ultra-fine bubble generator, characterized in that consisting of a back pressure control valve (10) for adjusting the ratio of liquid and gas. A pump (2) is used to suck the liquid from the reservoir (14) in which the liquid to be treated is stored and to inject the injector (4), and to pass the liquid to be passed through the injector (4) to dissolve the liquid. To mix the target gas into the liquid, and supply the liquid containing the target gas discharged from the injector (4) to the ultra-foam bubble generator (6) to produce a liquid containing ultra-fine bubbles, A liquid processing method using the ultra-foam bubble generator, comprising discharging the liquid containing the ultra-foam bubbles sequentially through the outlet (26) and the back pressure control valve (10) of the ultra-foam bubble generator (6). The method of claim 3, wherein And a gas storage tank (12) connected to the injector (4) and storing the target gas to supply the target gas to the injector.