JP2000254483A - Cavitation reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cavitation reactor whose capacity can be improved. SOLUTION: In a cavitation reactor provided with a pressurizing means 19 for pressurizing liquid to be treated 62 and a nozzle 21 for jetting out the pressurized liquid to be treated 62 into a reaction vessel 15, gas injection means 9, 11 for injecting gas into the liquid to be treated 1 fed to the pressurizing means 19 are provided and a fine bubble generating means 13 for making the gas injected into the liquid to be treated 1 into fine bubbles is provided between the gas injection means 9, 11 and the pressurizing means 19, thereby forcibly feeding the fine bubbles generated by the fine bubble generating means 13 and solid particulates such as dust in the air or in the gas injection means 9, 11 as nuclei of cavitation bubbles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cavitation reaction apparatus, and more particularly to a cavitation reaction apparatus that performs a process of decomposing substances in a liquid or a process of killing microorganisms by the action of cavitation bubbles.

[0002]

2. Description of the Related Art In a conventional cavitation reaction apparatus, cavitation is caused by ejecting a liquid to be treated, which is pressurized by a pressure pump, from a nozzle into a reaction tank, and the cavitation bubbles generated by the cavitation bubbles cause the liquid to be treated. We perform decomposition treatment of substances and killing microorganisms.

[0003]

However, in the conventional cavitation reactor, the amount of cavitation bubbles generated depends on the amount of dissolved gas in the liquid to be treated.
If the amount of dissolved gas is small, sufficient processing capacity cannot be obtained. Further, when the treatment is performed while circulating the water to be treated between the reaction tank and the pressure pump, as the treatment proceeds,
Due to the degassing effect of cavitation, dissolved gas in the liquid to be treated, which is the core of cavitation bubbles, is separated, so that cavitation is attenuated and sufficient treatment capacity cannot be obtained.

[0004] It is an object of the present invention to provide a cavitation reactor capable of improving the processing capacity.

[0005]

According to the present invention, there is provided a cavitation reactor comprising a pressurizing means for pressurizing a liquid to be treated, and a nozzle for jetting the pressurized liquid to be treated into a reaction tank. The above object is achieved by providing a gas injection means for injecting a gas into the liquid to be treated supplied to the pressure means.

With this configuration, the gas serving as the core of the cavitation bubbles can be forcibly supplied into the liquid to be processed by the gas injection means, so that the processing capacity depends on the amount of dissolved gas in the liquid to be processed. And the cavitation does not attenuate due to the cavitation degassing action. That is, the processing capability can be improved.

Further, a microbubble generating means is provided between the gas injecting means and the pressurizing means to make the gas injected into the liquid to be processed into fine bubbles, and the gas injected into the water to be processed is made into fine bubbles. Is desirable. According to this, the nuclei of the cavitation bubbles are significantly increased, and the reaction can be promoted. At this time, it is preferable that the fine bubbles have a diameter of 0.3 μm to 3 mm. According to this, since it functions as a core of cavitation bubbles, cavitation can be increased by ejecting a liquid to be treated in a state in which a large amount of fine bubbles are suspended from a nozzle.

In the nozzle, a concave portion is formed at the tip of a columnar body, a jet hole communicating with a liquid flow path formed in the body is formed at the bottom of the concave portion, and an opening is formed in a side wall of the concave portion. Is preferably used because cavitation can be increased.

In this case, it is preferable that the concave portion is formed so that the diameter gradually increases from the ejection hole of the nozzle toward the tip of the concave portion, because cavitation can be further increased.

[0010] In the nozzle, a jet hole is formed at the tip of the pipe whose end is closed, and the thickness of the tip where the jet hole is located is formed to be thicker than the thickness around the jet hole. Cavitation can be increased even if a material is used, which is preferable.

Further, the microbubble generating means includes a pipe having a closed end portion through which the gas-injected liquid flows, and a first ejection hole formed in a side wall of the front end portion of the pipe. A first miniaturization chamber formed with a hole, a collision surface facing the first jet hole, and a liquid to be processed spouted from the first jet hole, and a first miniaturization chamber. Also has a large volume, the first
If a device having a second micronization chamber communicating with the micronization chamber and a second ejection hole formed in a wall surface of the second micronization chamber is used, fine bubbles can be generated efficiently. preferable.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a cavitation reaction apparatus to which the present invention is applied will be described below with reference to FIGS. FIG. 1 is a schematic configuration diagram of a cavitation reaction apparatus to which the present invention is applied. FIG. 2 is a schematic configuration diagram of the gas injector. FIG. 3 is a sectional view of the fine bubble generator. FIG. 4A is a perspective view of a nozzle, and FIG.
FIG. 3A is a cross-sectional view taken along line AA of FIG.

As shown in FIG. 1, a cavitation reaction apparatus according to the present embodiment comprises a pipe 5 connecting raw water 1 and storage tank 3.
, A gas supply device 9 as a gas injection means provided downstream of the pump 7, and a gas injector 11,
The microbubble generator 13 provided at the end of the pipe 5 on the side of the storage tank 3 and provided at the bottom of the storage tank 3, and the pressurization provided in the pipe 17 connecting the storage tank 3 and the reaction tank 15. The pump 19 is connected to an end of the pipe 17 on the side of the reaction tank 15, and includes a nozzle 21 and the like attached to the bottom of the reaction tank 15.

The storage tank 3 is an open tank whose upper part is open, and the pipe line 5 from the gas injector 11 is opened from the opening.
The piping is directed toward the microbubble generator 13 installed at the bottom. The gas supply device 9 includes, for example, a fan, a blower,
Although various devices that can supply gas such as a compressor and a compressed gas cylinder can be used, in the present embodiment,
A blower that sucks and supplies air is used. That is,
The gas supply device 9 of the present embodiment suctions and supplies ambient air. As shown in FIG. 2, the gas injector 11 has a large-diameter portion 23 in which the diameter of the pipe 5 is increased, and a pipe 25 from the gas supply device 9 branches to the large-diameter portion 23 substantially vertically. It is T-shaped. Pipe 25 and enlarged diameter section 2
A multi-hole nozzle 29 is attached to the third communication portion 27.

As shown in FIG. 3, the microbubble generator 13 has a two-stage structure and includes an upper primary refining chamber 31 and a lower secondary refining chamber 33. A pipe 5 having a closed end is connected to the inside of the primary miniaturization chamber 31, and a jet hole 35 is formed in a side surface of the end of the pipe 5. In the primary miniaturization chamber 31, a wall surface 36 is formed substantially parallel to the outer wall surface of the conduit 5 at the position of the ejection hole 35,
The diameter of the lower part is larger than the space formed by the wall surface 36, and the diameter of the connecting portion with the secondary miniaturization chamber 33 is reduced. The secondary miniaturization chamber 33 is a space having a larger volume than the primary miniaturization chamber 31, and an ejection hole 37 is formed in the center of the side wall.

As the pressurizing pump 19, various pumps such as a plunger pump and a gear pump which can pressurize and discharge a gas-containing liquid can be used. In the present embodiment, a plunger pump is used. The reaction tank 15
As shown in FIG. 1, the tank 21 is a vertically long tank, and a nozzle 21 is attached to a bottom thereof through a nozzle mount 35 so as to face upward. Further, a drain valve for discharging the liquid in the reaction tank 15 is provided. A drain pipe 39 provided with 37 is provided.
In the upper part of the reaction tank 15, a supply pipe line 41 for supplying the water 40 after the cavitation reaction to the next step and the like, and an exhaust valve 43 for discharging the gas separated in the reaction tank 15.
And an exhaust pipe 45 provided with the exhaust pipe. The conduit 17 between the pressurizing pump 19 and the nozzle 21 is formed by a pressure-resistant hose 46. As shown in FIG. 4, the nozzle 21 has a hemispherical concave portion 49 whose diameter gradually increases from the ejection hole 47 toward the distal end at the distal end of the columnar body. That is, the ejection hole 47 is formed at the center of the bottom of the recess 49. In the side wall 51 forming the concave portion 49, a substantially rectangular notch-shaped opening 53 is formed at four positions at substantially equal positions. The flow path 55 side of the partition wall 57 in which the ejection hole 47 is formed at the center is formed in a tapered shape whose diameter gradually decreases from the periphery of the partition wall 57 toward the ejection hole 47.

The operation of the cavitation reactor having such a configuration and the features of the present invention will be described. Pump 7
As shown in FIG. 1, the raw water that is pumped up and flows through the pipe line 5, that is, the water 1 to be treated, is supplied with air supplied from the gas supply device 9 by the gas injector 23. At this time, the air supplied from the gas supply device 9, that is, the air supplied from the blower contains solid fine particles such as fine dust in the atmosphere or in the blower. Becomes

The treated water 1 into which the air has been injected is sent to the fine bubble generator 13, and as shown in FIG. 2, an ejection hole 35 provided at the end of the pipe 5 in the fine bubble generator 13. From the pump 7 at the pressure of the pump 7. This jet flow collides with the wall surface 36 of the primary miniaturization chamber 31, so that the gas injected into the water to be treated 1 is made into fine bubbles. The microbubbles generated in the primary refining chamber 31 are mixed well with the water 1 to be treated in the secondary refining chamber 33 and then further refined by the shearing force when the water 1 is ejected from the ejection holes 37. Is done. Therefore, a jet 61 containing a large amount of fine bubbles 60 is jetted from the fine bubble generator 13 into the storage tank 3. The fine bubbles 60 are shown in FIG.
As shown in (1), since the water to be treated 62 in the storage tank 3 is dispersed in the water to be treated 62 in the storage tank 3, a large amount of microbubbles 60 are in a floating state, and appears white and cloudy. At this time, the particle size of the fine bubbles 60 is mainly distributed in a range of about 3 to 70 μm. These fine bubbles 60 also serve as nuclei of cavitation bubbles. At this time, even larger bubbles are present, but bubbles having a particle size of about 3 mm can also be nuclei of cavitation bubbles. Since it takes time for the fine bubbles 60 to rise to the surface of the water, the water 62 to be treated in the storage tank 3 always contains the fine bubbles 6 serving as nuclei of cavitation bubbles.
0 is full.

The water to be treated 62 in the storage tank 3 is pressurized to a predetermined pressure by the pressurizing pump 19, and the high pressure
2 is ejected from the nozzle 21 into the reaction tank 15 toward above the reaction tank 15. The jet 63 formed by the jet of the high-pressure water to be treated 62 contains a large amount of fine bubbles serving as nuclei of the cavitation bubbles and solid fine particles such as dust, and thus is accompanied by intense cavitation. Further, as shown in FIG. 4, the nozzle 21 has the opening 53 in the side wall 51, so that the jet 6
By 3, the water around the nozzle 21 flows into the large-diameter cavity 49 through the opening 53 and is caught in the jet 63. Therefore, nuclei of cavitation bubbles such as fine bubbles and solid fine particles in the flowing water are further excited to promote cavitation.

The cavitation bubbles are microbubbles supplied into the water to be treated 40 and dissolved gases in the water to be treated 40 in the reaction tank 15, and after the cavitation reaction, these bubbles are united into large bubbles. And floats in the reaction tank 15 and accumulates at the top of the reaction tank 15. The accumulated gas is
The exhaust gas is discharged from the exhaust pipe 45 by the exhaust valve 43. The water to be treated 40 after the cavitation reaction is supplied from the supply pipe 41 to the next step or the like. A cavitation reaction can be performed while circulating the water to be treated 40 by circulating the water to be treated 40 in the reaction tank 15 to the storage tank 3 or the pressure pump 19.

Here, cavitation is a phenomenon in which a high-pressure liquid to be treated is jetted into the liquid and decompressed to generate air bubbles, and the generated air bubbles repeatedly grow, compress and collapse. When collapsed, it is adiabatically compressed.
The following effects are produced by such cavitation. (1) A high-temperature and high-pressure state is realized by adiabatic compression, and a thermal decomposition action occurs. (2) In a locally generated high temperature field, radicals and hydrogen peroxide are generated, and an oxidizing action occurs. (3) Impact pressure is generated when the bubbles collapse.

By the actions of (1) and (2), it is possible to decompose harmful substances such as dioxins, PCBs, ie, environmental hormones such as polychlorinated biphenyls and pesticides, or carcinogenic substances such as trichloroethylene. For example, the present invention can be applied to purification of a water source into which a harmful substance flows, treatment of a harmful substance stock solution, and the like. In addition, microorganisms can be killed by the actions (1) to (3). For example, applied to purification of water sources contaminated with toxic or pathogenic microorganisms such as Escherichia coli and chlorine-resistant protozoa, and water areas where phytoplankton that forms blue powder in lakes, ponds, etc. are growing it can. Thus, in the cavitation reaction device, without using a drug or the like,
It can decompose toxic substances and kill microorganisms.

An example of test results regarding the decomposition of toxic substances and the killing of microorganisms when water treatment is performed by the cavitation reaction device of the present embodiment will be described. FIG.
It is a figure which shows the result of having performed the decomposition test of trichlorethylene which is pollutants, such as groundwater. The decomposition rate on the vertical axis of the graph is the decomposition rate r of the cavitation reactor to be tested.
Is expressed as a relative value divided by the decomposition rate r ^* of the conventional cavitation apparatus in which nucleation of cavitation bubbles is not performed, that is, the cavitation reaction apparatus without any countermeasures. That is, when the cavitation reaction device without any countermeasure is tested, the decomposition rate r / r ^* = 1. In a test in which a gas containing almost no solid fine particles such as dust, that is, a nitrogen cylinder for supplying a clean gas was used as the gas supply device 9, r / r ^* = 1.13, and the decomposition ability of trichlorethylene was improved by about 13%. I do. When the gas supply device 9 for supplying the non-clean gas containing solid fine particles such as dust is used, r / r ^* = 1.35, and the decomposition ability of trichlorethylene is further improved. This is because, in addition to solid particles such as dust that has flowed into the water together with air, the nuclei of cavitation bubbles become nuclei, and nuclei provided as fine bubbles adhere stably to these solid particles such as dust. It is thought that it is possible.
As shown by the test results, the ability to decompose trichlorethylene is improved by supplying nuclei of cavitation bubbles.

FIG. 6 is a view showing the results of a decomposition test of tetrachlorethylene, which is a pollutant such as groundwater, similarly to trichlorethylene. The decomposition rate on the vertical axis of the graph is shown in the same manner as in FIG. 5, and when no countermeasures are taken, the decomposition rate r / r ^* = 1. In this test, the gas supply device 9 for supplying non-clean air containing solid fine particles such as dust is used, so that r / r ^* = 1.37, and the decomposition ability of tetrachloroethylene is improved by about 37%. As shown in the present test results, the ability to decompose tetrachlorethylene is improved by supplying nuclei of cavitation bubbles. As shown by these results, in the decomposition of harmful substances, the nuclei of cavitation bubbles are forcibly supplied to promote cavitation, whereby the decomposition ability can be improved.

FIG. 7 shows that the total number of bacteria including Escherichia coli was 5,000.
FIG. 4 is a diagram showing the results of a microorganism kill test performed on river water in a significantly contaminated state, exceeding the number of cells / cc. In this test, an open-type reaction tank 65 as shown in FIG. 9 is used instead of the reaction tank 15 of the present embodiment, and the nozzle 21 is attached so that the jet 63 is ejected in the horizontal direction.
Further, since the reaction tank 65 is an open type, the supply pipe 41 for supplying water in the reaction tank 65 is provided with a pump 67. The number of bacteria on the vertical axis of the graph shown in FIG. 7 is expressed as a relative value obtained by dividing the number of bacteria n per unit volume after the cavitation reaction treatment by the number of bacteria n ^* per unit deposition in the source water. . That is, if the number of bacteria after the treatment is the same as that in the raw water, n / n ^* = 1. In the conventional cavitation reactor without any countermeasures, n / n ^*あ り 0.17, and significant residual bacteria can be observed. On the other hand, when nuclei of cavitation bubbles are supplied according to the present invention, n / n ^* ≦
0.01, and the number of bacteria can be extremely reduced.

As described above, in the cavitation reaction apparatus of the present embodiment, solid particles such as fine bubbles and dust serving as nuclei of cavitation bubbles are forcibly supplied, so that cavitation bubbles can be stably generated. The processing capacity is not affected by the amount of dissolved gas in the liquid to be processed. Further, even if the processing proceeds and the degassing in the reaction tanks 15 and 65 due to cavitation progresses, the nucleus of the cavitation bubbles is supplied by the jet from the nozzle 21, so that the processing capacity does not decrease. That is, the processing capability can be improved. Furthermore, the cavitation reaction supplied by the cavitation bubble nucleus supplied increases the cavitation reaction more than in the conventional cavitation reaction device, so that the processing time can be shortened, and also, it is possible to prevent persistent bacteria and bacteria and protozoa that are strong in killing. Processing is also possible.

Further, in the present embodiment, the gas injector 11 having the structure as shown in FIG. 2 is used. However, the present invention is not limited to this. Such a device as described above may be used, or a T-shaped tube such as the gas injector 11 without the multi-hole nozzle 29 may be used.

Further, in the present embodiment, the fine bubble generator 13 having the structure as shown in FIG. 3 is used. However, the present invention is not limited to this. Fine bubble generating means, for example, a fine bubble generator equipped with a porous sintered metal nozzle can be used.
However, the microbubble generator 13 used in the present embodiment has a smaller pressure loss and less clogging of holes and the like than a microbubble generator having a porous sintered metal nozzle, and thus efficiently generates microbubbles. can do.

Although the storage tank 3 is used in this embodiment, the fine bubble generating means may be directly connected to the pressure pump 19 without using the storage tank 3. However, by providing the storage tank 3, the supply of the water to be treated 62 to the pressurizing pump 19 is performed at a pressure corresponding to the constant head of the storage tank 3, so that the operation of the apparatus can be further stabilized. .

In the present embodiment, the nozzle 21 as shown in FIG. 4 is used, but the present invention is not limited to this.
Various nozzles that can generate cavitation can be used. For example, in the nozzle 21, a rectangular notch-shaped opening 53 is formed in the side wall 51, but instead of this, a hole may be formed in the side wall 51, and the number of the opening 53 and the number of holes may be changed. Good. Furthermore, a hemispherical recess 4
9 may be formed in a tapered shape whose diameter gradually increases toward the tip. Further, a nozzle 69 having a tip having another shape as shown in FIG. 9 can be used. In the nozzle 69, the thickness of the tip wall 70 of the flow path 55 at the position of the ejection hole 47 formed in the center of the tip wall 70 becomes gradually thicker than the thickness of the periphery of the tip wall 70. Are formed so as to project toward the flow path 55 in a tapered shape with the ejection hole 47 as a center. Therefore, a contraction of the liquid jet, that is, a contraction portion 71 of the liquid jet is generated in the ejection hole 47, and cavitation bubbles are generated in the contraction portion 71, thereby increasing cavitation in the jet flow downstream of the contraction portion 71. is there. Also,
Instead of the tapered projection of the tip wall 70, the ejection hole 4
A cylindrical projection surrounding the periphery of 7 may be formed, and these tapered or cylindrical projections may be formed toward the outside of the nozzle. The pressure loss of the nozzle 69 is slightly larger than that of the nozzle 21 shown in FIG. FIG.
In the nozzle 21, a nozzle having a cylindrical concave portion, a nozzle having no opening in the side wall 51, and a nozzle having no concave portion 49 may be used instead of the hemispherical concave portion 49. . However, cavitation can be increased by using the nozzles 21 and 69 as shown in FIGS.

In the present embodiment, solid fine particles such as dust contained in the air from the gas supply device 9 and microbubbles made fine by the microbubble generator 13 are used as nuclei of cavitation bubbles. The effect of the present invention can be obtained even when the cavitation bubbles are supplied as nuclei.
However, as shown in FIG. 5, supplying both solid fine particles such as dust and fine bubbles as nuclei of cavitation bubbles has a greater effect of improving the processing capacity by the cavitation reaction.

Further, the present invention is not limited to the apparatus having the reaction tanks 15 and 65 having the configuration of the present embodiment, but various apparatuses capable of generating a jet in the liquid to be treated by the nozzle 21, for example, When installing the nozzle 21 directly in the source water,
That is, the present invention can be applied to a case where the reservoir itself is used as a reaction tank.

Further, in the present embodiment, the case where the raw water such as groundwater, rivers, lakes and marshes into which harmful substances and the like have flowed was shown, but the cavitation reaction apparatus of the present invention uses a harmful substance solution such as a trichloroethylene stock solution. It can also be processed directly.

[0034]

According to the present invention, the processing ability by the cavitation reaction can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of one embodiment of a cavitation reaction device to which the present invention is applied.

FIG. 2 is a perspective view showing a schematic configuration of an embodiment of a gas injector.

FIG. 3 is a cross-sectional view illustrating a schematic configuration of an embodiment of a fine bubble generator.

FIG. 4A is a perspective view of one embodiment of a nozzle,
(B) is sectional drawing in AA of (a).

FIG. 5 is a view showing the results of a decomposition test of trichlorethylene.

FIG. 6 is a view showing the results of a decomposition test of tetrachloroethylene.

FIG. 7 is a view showing the results of a test for killing microorganisms.

FIG. 8 is a diagram showing only a pressure pump and a reaction tank in another embodiment of the cavitation reaction device.

FIG. 9 is a cross-sectional view of another embodiment of a nozzle.

[Explanation of symbols]

 1, 40, 62 Water to be treated 7 Pump 9 Gas supply device 11 Gas injector 13 Fine bubble generator 15 Reaction tank 19 Pressurizing pump 21 Nozzle

Continued on the front page (72) Inventor Kazunori Fujita 3-36 Takara-cho, Kure-shi, Hiroshima Babcock Hitachi Kure Research Laboratory F-term (reference) 4G075 AA37 BA05 BD13 BD27 EA01 EB21 EC01

Claims (6)

[Claims] 1. A cavitation reactor comprising a pressurizing means for pressurizing a liquid to be treated and a nozzle for jetting the pressurized liquid to be treated into a reaction tank, wherein the liquid is supplied to the pressurizing means. A cavitation reaction device comprising a gas injection means for injecting a gas into the liquid to be treated. 2. The apparatus according to claim 1, further comprising a fine bubble generating means for converting the gas injected into the liquid to be processed into fine bubbles between the gas injection means and the pressurizing means. Cavitation reactor. 3. The fine bubbles have a diameter of 0.3 μm to 3 μm.
The cavitation device according to claim 1, wherein the cavitation device has a size of mm and functions as a core of cavitation bubbles. 4. The nozzle has a concave portion formed at the tip of a columnar body, a jet hole communicating with a liquid flow path formed in the body at the bottom of the concave portion, and a side wall of the concave portion. The cavitation device according to claim 1, wherein an opening is provided. 5. The nozzle is formed such that a jet hole is formed at a tip end of a pipe whose end is closed, and a thickness of the tip portion where the jet hole is located is thicker than a wall thickness around the jet hole. The cavitation reaction device according to claim 1, wherein the cavitation reaction device is used. 6. The microbubble generating means includes a pipe having a closed end portion through which the gas-injected liquid flows and a second pipe formed in a side wall of the front end portion of the pipe. A first jetting hole, a first miniaturization chamber in which a collision surface facing the first jetting hole and against which the liquid to be processed spouted from the first jetting hole is formed, A second miniaturization chamber having a larger volume than the miniaturization chamber and communicating with the first miniaturization chamber;
The cavitation reactor according to any one of claims 1 to 5, further comprising a second ejection hole formed in a wall surface of the second miniaturization chamber.