JP3831892B2 - Cavitation jet reactor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reactor (reactor) that performs decomposition of harmful substances in water and sterilization of pathogenic bacteria by a high-speed water jet accompanied by intense cavitation in water.
[0002]
[Prior art]
Harmful organic compounds dissolved in water, such as trichloroethylene and tetrachloroethylene, which are typical carcinogenic groundwater contaminants, can be decomposed into harmless substances by the action of cavitation. In addition, when cavitation is used, cells are destroyed and pathogenic E. coli and Cryptosporidium (a kind of protozoa) that is a chlorine-resistant pathogenic symptom can be destroyed and water can be rendered harmless.
[0003]
Ultrasound is one of the means for generating cavitation, but it is not energy efficient. In addition to this, there is also a method of turning a low speed like a stirring blade at high speed in water, but the most easy and continuous method to generate extremely severe cavitation is to jet a water jet at high speed in water. Is the method.
[0004]
When high-pressure water is injected into the water from the nozzle, intense cavitation occurs in the underwater water jet. The strength and throughput of cavitation can be easily adjusted by the nozzle ejection hole diameter and the discharge pressure in a high-pressure pump (using a plunger pump or a centrifugal pump).
[0005]
An important point in this technique is how intense cavitation is created in the water jet. The key device is of course the nozzle. -On the other hand, even if the generation of cavitation in the nozzle is good, cavitation cannot be used efficiently if there is a problem in the structure such as the dimensions of the reactor (reaction vessel) or the flow conditions in the reactor.
[0006]
Therefore, in a water jet reactor using cavitation, it can be said that not only the nozzle is a key device but also a reactor that performs a reaction by cavitation is an important element that cannot be neglected.
[0007]
[Problems to be solved by the invention]
In the prior art, a cylindrical reactor is used in which the inner diameter and length of the reaction vessel are much larger than the effective cavitation reaction region. The reactor having this structure has the following problems.
[0008]
(1) The cavitation reaction region is not sufficiently large.
(2) Mixing with the ambient water inside the cylindrical reactor, the submerged water jet accompanied by cavitation is diluted, and as a result, the cavitation reaction efficiency cannot be increased.
[0009]
The conventional nozzle attempts to develop cavitation at the outlet of the ejection hole by the action of intense contraction flow at the ejection hole. Cavitation generated when such a nozzle is used is powerful in the vicinity of the nozzle, but there is a problem that the cavitation region is not large. In short, in the prior art, there has been a lack of ingenuity to expand the cavitation area and effectively utilize it.
[0010]
An object of the present invention is to solve the above-mentioned problems and to provide a novel cavitation jet reactor having a sufficiently large reaction area effective for cavitation and high reaction efficiency.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the following means are employed in the present invention. First, the cavitation jet reactor that injects the test contaminated water to be treated from the nozzle as a high-speed water jet is formed into an elongated shape, and the inside of the reactor is pressurized.
[0012]
When the nozzle ejection hole diameter is Dj, the inner diameter Dr of the reactor is
Dr = (16-42) × Dj …………………………………… (1)
Select from the range.
[0013]
In addition, the length Lr of the reactor is
Lr = (300-1600) × Dj ……………………………… (2)
Select from the range.
[0014]
Further, the injection pressure Pj of the nozzle water jet in the present invention is:
Pj = 110 to 1500 kgf / cm ² (3)
Range.
[0015]
The pressure Pr in the reactor is
Pr = 0.6 × 5.0 kgf / cm ² …………………………… (4)
Adjust so that it is within the range. In this case, the internal pressure Pr of the reactor can be set at the pressure regulating valve at the reactor outlet.
[0016]
The present invention has the following effects.
First, by elongating the reactor, cavitation generated in a high-speed water jet underwater extends in the axial direction of the water jet. In this way, the effective reaction area of cavitation is expanded and the cavitation reaction efficiency is improved.
[0017]
Next, when the reactor is operated so as to be in a pressurized state, excess bubbles disappear. As a result, the cavitation region is reduced, but the cushioning (buffering) action of cavitation is eliminated, so that the cavitation is in a so-called “few minority” state, and the reaction efficiency by cavitation is improved.
[0018]
As described above, the effective reaction area of cavitation is expanded and the reaction efficiency is improved, whereby the power of cavitation is enhanced and the water purification ability is increased. Furthermore, the structure of the reactor itself can be made compact.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, the configuration of the present invention will be described.
FIG. 1 is a schematic sectional view of a structure of a cavitation jet reactor embodying the present invention. The compact reactor 14 has a cylindrical shape, and high-pressure water 2 obtained by pressurizing water to be treated is injected as a submerged water jet 15 accompanied by cavitation from a nozzle 1 provided at an upstream end thereof.
[0020]
The nozzle 1 is installed at the upstream end of the compact reactor 14 via the nozzle mount 13. The compact reactor 14 is much smaller in both length and diameter than the cylindrical reactor 10 of the reference example shown in FIG.
[0021]
In this embodiment, the inner diameter Dr of the reactor is selected from the range of the following formula (1), where Dj is the nozzle ejection hole diameter.
Dr = (16-42) × Dj ………………………………………… (1)
[0022]
On the other hand, the effective length Lr of the reactor is selected from the range of the following equation (2) with respect to the ejection hole diameter Dj.
Lr = (300-1600) × Dj ……………………………… (2)
[0023]
Moreover, the injection pressure Pj in the nozzle 1 is selected from the range of following Formula (3) in this invention.
Pj = 110 to 1500 kgf / cm ² …………………………… (3)
[0024]
In the present invention, the compact reactor 14 is in a pressurized state, and the pressure of the pressurized ambient water 8a, that is, the reactor internal pressure Pr is selected from the range of the following equation (4).
Pr = 0.6 to 5.0 kgf / cm ² (4)
[0025]
The reactor internal pressure Pr is adjusted by a pressure adjusting valve 17 provided in the discharge line 16 and simultaneously monitored by a pressure gauge 18. When the compact reactor 14 is pressurized as described above, the underwater water jet 15 accompanied by cavitation under pressure has a small diameter and a short length, and the volume in the cavitation region is also small.
[0026]
As a result, this phenomenon made the reactor compact. Further, it is possible to prevent the cavitation from colliding with the rear surface of the compact reactor 14.
[0027]
According to the embodiment of the present invention, although the cavitation region becomes small, excess bubbles disappear, so that the effect of attenuating the power of cavitation is reduced, so that the volume is small, but the cavitation is powerful.
[0028]
The example of FIG. 2 is an example in which the inside of the elongated cylindrical reactor 11 is pressurized, but less internal pressure is applied compared to the example of FIG. In this example, in the nozzle having the ejection hole diameter Dj = 0.6 to 1.6 mm, the reactor inner diameter Dr, the reactor length Lr, the injection pressure Pj, and the reactor internal pressure Pr are numerical values according to the following equations (1a) to (4a), respectively. It was adopted.
[0029]
Dr = 16 × Dj …………………………………………………… (1a)
Lr = 1600 × Dj ………………………………………… (2a)
Pj = 350 kgf / cm ² ……………………………………… (3a)
Pr≈0.7 kgf / cm ² ……………………………………… (4a)
[0030]
As can be easily seen from FIG. 2, in such a tubular reactor, the cavitation region extends with respect to the axial direction of the jet 12, and the cavitation region is greatly increased. However, in this state, since there are many extra bubbles, the cavitation strength is not necessarily high.
[0031]
In short, the example shown in FIG. 1 increases the internal pressure of the reactor from the state of FIG. 2 and reduces the cavitation area, but eliminates excess bubbles to make the cavitation more powerful and further reduce the reactor size. It is a thing.
[0032]
FIG. 3 is a diagram showing the overall configuration of the cavitation jet reactor according to the present invention. The sample contaminated water 21 put in the tank 22 is fed to the plunger pump 20, pressurized to a predetermined pressure to become high-pressure water 2, and fed to the nozzle 1 through the high-pressure hose 19.
[0033]
When the high-pressure water 2 is injected from the nozzle 1 into the compact reactor 14, the compact reactor 14 is also filled with water, so that an underwater water jet 15 accompanied by cavitation under pressure is obtained. Here, toxic substances are decomposed or sterilized by the action of cavitation.
[0034]
The treated water is discharged out of the system as treated water 25 through a discharge line 16 provided at the outlet of the compact reactor 14. On the other hand, if the predetermined decomposition level has not been reached, the water is returned to the tank 22 by the operation of the switching valve 24 and sent to the compact reactor 14 again.
[0035]
FIG. 4 is a sectional view showing an example of a nozzle structure used for causing cavitation developed in an underwater water jet. In the nozzle 1a of this example, the high-pressure water 2 to be treated is guided through the high-pressure water supply channel 3, and is rapidly depressurized and accelerated by the squeezing portion 9 (diameter contraction portion), and is ejected from the ejection hole 4 with cavitation. It becomes the underwater water jet 7a.
[0036]
A bell-shaped enlarged cavity 5 is provided at the outlet of the ejection hole 4. A circulating vortex 6 is generated around the jet 7a immediately after exiting from the ejection hole 4. The action of the circulating vortex 6 is to cause bubble nuclei in the ambient water 8a to flow into the jet 7a, and further to apply pressure fluctuations to the jet 7a, both of which promote cavitation.
[0037]
In this embodiment, in order to extend the cavitation region in the submerged water jet 7a with cavitation in the axial direction, the squeezing (both swing) angle θ is selected from a range of 10 degrees to 120 degrees. In the example shown in FIG. 4, θ = 90 degrees.
[0038]
Next, the function of the example of the present invention will be described.
FIG. 5 shows the relationship between the reactor inner diameter Dr and the length Lcav of the cavitation region in the jet axis direction. The length Lcav of the cavitation region on the vertical axis is made dimensionless by dividing by the length Lcav ^* of the cavitation region (jet axis direction) in Dr → ∞ (infinitely wide free space).
[0039]
As the reactor inner diameter decreases, the cavitation region extends in the axial direction and Lcav increases. In the present invention example, the Dr region in which the cavitation region increases rapidly is used as the reactor size range. As the reactor is made thinner (Dr becomes smaller), cavitation collides with the inner wall of the reactor, but even under this condition, the cavitation region becomes considerably longer.
[0040]
However, there is a problem that the inner wall surface of the reactor causes erosion, and if the fine iron particles eroded and fall off circulate in the system shown in FIG. 3, the erosion of the nozzle is remarkably accelerated. is there. Therefore, the reactor cannot be made too thin.
[0041]
FIG. 6 shows how the volume in the cavitation region changes when a thin tube reactor is used as shown in FIG. 2 in comparison with the reference example (FIG. 11). The volume V of the cavitation region on the vertical axis was made dimensionless by dividing by the volume V ^* of the cavitation region in the reference example (FIG. 11). From this result, it was found that the volume of the cavitation region increased by 40% or more by making the reactor into a thin tube type.
[0042]
On the other hand, FIG. 7 shows the change of the cavitation region due to the reactor being further pressurized as shown in FIG. The volume V of the cavitation region on the vertical axis is expressed as a relative value by dividing by the volume V ^* of the cavitation region in the reference example (FIG. 11).
[0043]
It can be seen that if the pressure in the reactor is increased, the volume in the cavitation region is reduced to about 2/5 of the case without countermeasures. This is because if the internal pressure of the reactor rises, excess bubbles in the cavitation jet (which attenuates the cavitation power) disappear.
[0044]
FIG. 8 compares the volume V of the cavitation region with the reference example (FIG. 11) in the combination of “reactor thinning + reactor internal pressure increase” which is the final target of the present invention. The volume V of the cavitation region on the vertical axis is made dimensionless by dividing by the volume V ^* of the cavitation region in the reference example (FIG. 11). In the reference example, V / V ^* = 1. In an embodiment of the invention, the cavitation volume is reduced by about 20%.
[0045]
As described above, according to the present embodiment, it is understood that bubbles that attenuate the cavitation power in the cavitation jet disappear while the cavitation region is reduced, so that the entire cavitation can be powerful.
[0046]
FIG. 9 is a test result showing the effect of the present invention. The treated water amount Q of the embodiment shown in FIG. 1 was compared with the treated water amount Q ^* in the reference example (FIG. 11). According to the means of the present invention, it became clear that the processing capacity can be expanded by 40% or more despite the fact that the reactor becomes compact.
[0047]
Next, another embodiment of the nozzle applied to the cavitation jet reactor of the present invention will be described with reference to FIG. The nozzle 1b of this example is devised for extending in the axial direction so that it can be applied to an elongated reactor.
[0048]
The basic structure of the nozzle 1b is a structure opposite to that of the nozzle 1c shown in FIG. 12 as a reference example, and a gradual diameter contraction part (squeezing part) is provided between the high-pressure water supply channel 3 and the ejection hole 4. ) 9 is provided.
[0049]
In this way, cavitation immediately after exiting from the ejection hole 4 is not severe, but cavitation develops as it goes downstream of the submerged water jet accompanying cavitation, and the cavitation extends in the axial direction of the jet. .
[0050]
This nozzle is therefore suitable for the new reactor of the present invention. Further, this nozzle also has a feature that the pressure loss is small as compared with the nozzle of the reference example shown in FIG.
[0051]
Here, a reference example of the present invention will be described with reference to FIGS.
As shown in FIG. 11, the reactor of the present reference example has a cylindrical reactor 10 having a far larger inner diameter Dr and length Lr than the submerged water jet 7b with cavitation which is an effective cavitation reaction region. It is used.
[0052]
In the reactor having such a structure, the cavitation reaction region is small, and the submerged water jet 7b accompanied by cavitation is mixed with the surrounding water 8b inside the cylindrical reactor 10 and diluted, thereby increasing the cavitation reaction efficiency. I can't.
[0053]
In addition, the nozzle 1c having the structure shown in FIG. 12 is intended to develop cavitation at the outlet of the ejection hole by the action of intense contraction flow in the ejection hole 4. However, when the nozzle 1c is used, Although the cavitation occurring in the nozzle is powerful in the vicinity of the nozzle, the cavitation region is not necessarily large.
[0054]
【The invention's effect】
The effects produced by the present invention are summarized as follows.
(A) Effectively use the flow region of the reactor that injects the water jet, and can eliminate the cushioning action by removing excess bubbles, thus increasing the cavitation efficiency and greatly improving the water purification capacity of the cavitation jet reactor. Can be improved.
[0055]
(B) In the above effect (A), since no external energy is supplied, the energy cost can be reduced.
(C) Although the reactor is elongated, it can be made compact as a whole.
(D) In relation to (A) and (B) above, the effects of increasing the amount of water to be purified, shortening the water purification process, and expanding the substances to be treated are produced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of the present invention.
FIG. 2 is a configuration diagram showing another embodiment of the present invention.
FIG. 3 is a diagram showing an entire system using the present invention.
FIG. 4 is a cross-sectional view of a nozzle used in the present invention.
FIG. 5 is a diagram showing experimental results on which the present invention is based.
FIG. 6 is a diagram showing a result of an experiment on which the present invention is based.
FIG. 7 is a diagram showing experimental results on which the present invention is based.
FIG. 8 is a diagram showing test results that specifically demonstrate the effects of the implementation of the present invention.
FIG. 9 is a diagram showing test results that specifically demonstrate the effects of the implementation of the present invention.
FIG. 10 is a cross-sectional view showing another embodiment of a nozzle used in the present invention.
FIG. 11 is a block diagram showing a reference example of the present invention.
FIG. 12 is a cross-sectional view of a nozzle in a reference example of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c Nozzle 2 High pressure water 3 High pressure water supply flow path 4 Ejection hole 5 Enlarged cavity 6 Circulating vortex 7a, 7b Underwater water jet with cavitation 8a Pressurized ambient water 8b Ambient water 9 Part)
DESCRIPTION OF SYMBOLS 10 Cylindrical reactor 13 Nozzle mount 14 Compact reactor 15 Underwater water jet 16 with cavitation under pressure 16 Discharge line 17 Pressure regulating valve 18 Pressure gauge 19 High pressure hose 20 Plunger pump 21 Test contaminated water 23 Circulation line

Claims (5)

In a cavitation jet reactor in which cavitation is generated by a water jet of water to be treated which is jetted into water in a reaction vessel from a nozzle, the inside of the reaction vessel is maintained in a pressurized state, and the jet of the water jet Cavitation is characterized in that it is formed in the direction of an elongated cylinder or square cylinder, and the equivalent diameter Dr is selected from the range of Dr = (16 to 42) × Dj, where the nozzle hole diameter is Dj. Jet reactor. 2. The cavitation jet reactor according to claim 1 , wherein the effective length Lr of the reaction vessel is selected from the range of Lr = (300 to 1600) × Dj where the nozzle hole diameter is Dj. The injection pressure Pj at the nozzle is Pj = 110 to 1500 kgf / cm ^2.
The cavitation jet reactor according to claim 1 or 2 , wherein the cavitation jet reactor is selected from the range. The pressure Pr of the reaction vessel, Pr = 0.6~5.0kgf / cm ^2, cavitation jet reactor according to any one of claims 1 to 3 formed by selecting from the range of. The nozzle is, cavitation jet reactor according to any one of the two Furishibori angle θ is the constriction of toward the ejection hole from the high pressure water supply unit, according to claim 1 to 4 is less than 10 degrees or more 120 degrees.

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