JP2000167546A - Water jet reaction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water jet reaction device for clarifying the relation between the cavitation and the hazardous chemical substance decomposition and sterilization and securely provide the sterilization effect and the purification effect on polluted water. SOLUTION: In a water jet reaction device for decomposing and/or sterilizing hazardous chemical substance dissolved in the water and/or hazardous bacteria suspended in the water by the cavitation generated by a water jet (underwater water jet 9) jetted out of a nozzle provided in water flows in a reactor 5, the average flow velocity ut, the average retention time tr, the jet flow velocity uj of water jet, the water jet flow velocity uj, the gas melting degree α/αs, the water temperature Tw and the like is the reactor 5 are selected in given ranges, and the decomposition of chemical substrates and the sterilization of hazardous bacteria are carried out by the cavitation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water jet reactor (reactor) for purifying polluted water areas and wastewater by utilizing cavitation generated in a water jet.

[0002]

2. Description of the Related Art Intense cavitation occurs in a water jet that blows water in water as a high-speed jet jet. Cavitation is a phenomenon in which a large number of small bubbles repeatedly grow, compress, and collapse in a short time. In particular, when the bubbles collapse, adiabatic compression causes the following unique effects.

[0003] Adiabatic compression reveals a high-temperature, high-pressure state, and a thermal decomposition action occurs.

[0004] Locally generated high temperatures generate radicals and hydrogen peroxide (H ₂ O ₂ ), which produces a strong oxidizing effect.

[0005] When a bubble collapses, a strong impact pressure is generated.

[0006] According to the above function, the decomposition of each of the above substances with respect to an environmental hormone such as dioxin, PCB and pesticide, or a stock solution of a carcinogenic detergent such as trichloroethylene or water in which the detergent is dissolved. Processing can be performed. In addition, according to the above-mentioned actions, plankton such as pathogenic bacteria such as Escherichia coli and chlorine-resistant protozoa and blue-green can be killed, so that water sources contaminated with these pathogens and plankton such as blue-green can be reduced. It is possible to purify water areas that have abnormally bred. In particular, both act on water contaminated with both the above-mentioned environmental hormones and pathogenic bacteria, and at the same time, a special agent such as a flocculant is not required.

[0007] Such a phenomenon is already known, and by utilizing this phenomenon, a throat 3 is provided inside a pipe 1 through which a target liquid flows, as shown in FIG. It is also known that cavitation is generated in the jet 4 ejected from the throat 3 to promote the chemical reaction (Steven Ley & Ca)
rolin Low [Ultrasonic organic synthesis-from basic to applied-Sprin
g-Verlag, Tokyo, (1991) Translated by Iwasaki and Ogawa.

[0008]

However, in the above-mentioned trials, it is examined whether or not the chemical reaction is promoted by generating cavitation. However, the amount of cavitation generated or the amount of development and the degree of promotion of the chemical reaction are considered. Has not been fully considered. For this reason, the actual relationship between the cavitation size and the reaction in the tubular body is unclear when it is used to promote a chemical reaction or a sterilization action, and it is still insufficient for practical use.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a water jet reactor which can clarify the relationship between cavitation and the above-mentioned reaction and can surely obtain a sterilizing effect and a purifying effect. To offer.

[0010]

In order to achieve the above object, a first means is to dissolve harmful chemical substances in water and / or
Or, in a water jet reaction apparatus for decomposing and / or disinfecting harmful bacteria floating in water by cavitation generated by a water jet ejected from a nozzle installed in flowing water of the reactor, an average flow rate in the reactor ut is set to be in the range of 0.004 ≦ ut (m / s) ≦ 0.03.

[0011] The second means is that in a water jet reactor of the same premise, the average residence time t in the reactor is t
r is set to be in a range of 40 ≦ tr (sec) ≦ 320.

The third means is that, in a water jet reactor based on the same premise, the jet flow velocity uj of the water jet ejected from the ejection hole of the nozzle in the reactor is set to 400 ≦ uj (m / s) ≦ 1600. Is set so as to fall within the range.

The fourth means is that, in a water jet reactor based on the same premise, the gas solubility is set to 0.80 ≦ α / αs ≦ 1.30 (where α: dissolved amount of gas, αs: saturated gas) Dissolution amount)
The amount of dissolved gas in the contaminated raw water is set so as to fall within the range described above.

The fifth means is characterized in that, in the water jet reaction apparatus on the same premise, the water temperature in the reactor tube is set within a range of 15 ≦ Tw (° C.) ≦ 85.

A sixth means is that, in a water jet reaction apparatus on the same premise, the tip of the nozzle is projected toward the center of the reactor so that a circulating vortex is generated upstream of the tip of the nozzle. It is characterized by the following.

The seventh means is characterized in that a water jet reactor is constituted by at least two means of the first to fifth means.

In the above description, the average value is conventionally provided with an upper bar, but is omitted here.

According to the above-mentioned means, it becomes possible to appropriately set the average flow velocity in the pipe in the reactor or the average reaction time in the reactor.
In addition, by-products at the time of reaction assembly can be stably generated. In addition, by setting the passage time in one reactor and the number of circulations to the reactor optimally, the reaction within a unit time can be more actively performed.

The optimum water jet injection conditions are determined by the relationship between the injection pressure at the nozzle and the cost of the liquid supply equipment, that is, the cost of the pump. Regarding the gas dissolving conditions, if the amount of dissolved gas in the liquid to be treated is large, the number of bubble nuclei of cavitation increases and cavitation sufficiently develops, thereby improving the treatment efficiency. As the temperature condition, a temperature suitable for generating cavitation is selected.

Further, the tip of the nozzle is projected toward the center of the reactor so as to generate a circulating vortex upstream of the tip of the nozzle, so that the liquid flow circulating in the reactor is smoothly jetted. It will flow into. This improves the mixing and stirring in the reactor, and increases the efficiency of the reaction treatment.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, components that can be regarded as the same are denoted by the same reference numerals, and redundant description is omitted as appropriate.

FIG. 1 is an explanatory diagram showing an overall system of a purification process including a water area purification device provided with a water jet reactor (water jet reactor) according to an embodiment of the present invention. In the figure, the water purifying apparatus includes a feed tank 24, a plunger pump 20, a tubular reactor 5, reservoir tanks 17, 22, circulating pumps 18, 23, and a pump 26, and a pipe reactor 5 and a reservoir tank 22 from the plunger pump 20. And a piping system including a three-way switching valve 21 provided in a path leading to the air conditioner. A nozzle 8 is provided at one end of the tubular reactor 5 via a nozzle mount 7 so as to jet a water jet into the tubular reactor 5.

The contaminated raw water 28 to be purified is pumped by a pump 26 and guided through a pump line 27 into the feed tank 24. The contaminated raw water 28 in the feed tank is pressurized to a predetermined pressure (for example, 500 kgf / cm ² ) by the plunger pump 20 and sent to the nozzle 8 from the high-pressure hose 6 via the three-way switching valve 21. The three-way switching valve 21 is for adjusting the discharge pressure of the plunger pump 20, and the contaminated raw water released for pressure adjustment is removed by the second circulating pump 23 to the second circulating pump 23.
Through the circulation line 25 in the feed tank 24 again. The nozzle 9 for jetting a water jet is installed so as to protrude toward the inside of the tubular reactor 5.

The tubular reactor 5 is elongated in the horizontal direction, and the downstream side (the right side in the figure) is upstream (the left side in the figure) so that bubbles remaining in the reactor 5 float and the bubbles can be discharged as quickly as possible. ). This inclination is set to 5 degrees from horizontal in this embodiment. The inside of the tubular reactor 5 is filled with treated water in order to eject the contaminated raw water 28 as a water jet, and the water jet becomes an underwater jet 9 with cavitation. Then, the action of the cavitation 9 promotes the decomposition of harmful chemical substances in water and the sterilization of pathogenic bacteria.

The water overflowing from the tubular reactor 5 due to the jet of the water jet from the nozzle 8 is:
It is discharged through the overflow pipe 16. At that time, when the treatment is performed sufficiently, it is discharged as a treated water 29 out of the system of the apparatus, and when the decomposition or sterilization is insufficient,
It is temporarily stored in the first reservoir tank 17, returned to the feed tank 24 again through the first circulation line 19 by the first circulation pump 18, and supplied again as untreated water to the tubular reactor 5 side.

FIG. 2 is an explanatory diagram showing the relationship between water jet and cavitation in the tubular reactor 5 of FIG.

In FIG. 2, the jet velocity uj of the water jet from the jet port at the nozzle 8 is selected from the range of 400 ≦ uj (m / s) ≦ 1600 (1). If the jet velocity uj is lower than this condition (uj <400 m / s), cavitation does not sufficiently develop. On the other hand, if uj is made larger than this (uj> 1600 m / s), the power of the cavitation gradually increases, but the plunger pump 20 needs to be made larger. If the size of the pump 20 is increased, the equipment cost becomes excessive, and it becomes economically unsuitable.

The cavitation of the submerged water jet disappears with the diffusion of the jet, and the inside of the tubular reactor 5 becomes a pipe flow having a plug-type velocity distribution as shown in the figure. The dimensions of the tubular reactor 5 and the jetting conditions of the water jet are set so as to be in the range of 0.004 ≦ ut (m / s) ≦ 0.03 (2). The average reaction (residence) time tr in the tubular reactor 5 is selected from the range of 40 ≦ tr (sec) ≦ 320 (3). For a shorter time (tr
In <40), the reaction and sterilization do not proceed, and it is difficult to finish the treatment. On the other hand, if the time is longer (tr> 320), there is no rapid progress of the reaction and the sterilization, and the tubular reactor 5 becomes unnecessarily long, resulting in an increase in equipment cost.

Underwater water jet 9 with cavitation
In order to sufficiently develop the cavitation in the above, it is not sufficient to merely optimize the injection conditions in the nozzle 8 and the specifications of the tubular reactor 5, and the condition of the contaminated raw water is also important. The dissolved gas in the water becomes the nucleus of the cavitation. In this embodiment, the gas solubility is 0.80 ≦ α / αs ≦ 1.30 (4) (where α is the dissolved amount of gas, αs : Saturated dissolved amount of gas)
Adjust the dissolved amount of gas in the contaminated raw water so that If the gas solubility is lower than this (α / αs <0.80), the power of cavitation decreases because the number of bubble nuclei in the contaminated raw water is small. On the other hand, if the gas solubility is higher than this (α / αs> 1.30), cavitation cannot be enhanced even if the number of bubble nuclei increases further.

In the tubular reactor 5, the condition of the water temperature at which cavitation occurs also strongly affects the power of cavitation. Therefore, in this embodiment, the water temperature in the tubular reactor 5 is set within the range of 15 ≦ Tw (° C.) ≦ 85 (5). If the temperature is lower than this (Tw <15 ° C.), since the viscosity of water is high and the surface tension is large, the growth of cavitation bubbles is suppressed, and as a result, the strength of cavitation decreases. Conversely, if the temperature is higher than this (Tw> 85 ° C.), subcooled boiling starts in the tubular reactor 5, and bubble nuclei in the water are consumed for boiling, and large massive boiling bubbles are generated in the tubular reactor 5. If it stays in 5, the cushioning effect also occurs, and in any case, the power of cavitation decreases.

In this embodiment, the pressure in the tubular reactor 5 is substantially atmospheric pressure (normal pressure), and the water temperature described here is also a condition for normal pressure. In the case of sterilization, when the water temperature exceeds 60 ° C., Escherichia coli is weakened and killed regardless of the cavitation intensity. Further, in FIG. 2, each unit equivalent to that in FIG. 1 is denoted by the same reference numeral, and description thereof is omitted.

FIG. 3 is an enlarged sectional view showing the ejection portion of the nozzle 8 in FIG. 1 and FIG. The high-pressure water 11 is guided from the high-pressure water supply flow path 12 on the upstream side of the nozzle 8, decompressed and accelerated by the diameter contraction part 15, and blows out from the ejection hole 14 at a high speed given in the range of the above formula (1), and cavitation. And a submerged water jet 9. A dome-shaped enlarged cavity 13 is provided at the tip of the ejection hole 14, and an unstable vortex is actively generated inside the enlarged cavity 13 to amplify cavitation in the jet 9.

FIG. 4 is a view showing another embodiment in which the nozzle 8 is fixed so as to protrude to the inside of the tubular reactor 5. The nozzle 8 is mounted on the nozzle mount 7 and fixes the nozzle mount 7 to the end of the tubular reactor 5 on the upstream side in the high-pressure water flow direction. The embodiment of FIG.
Only the amount of protrusion of the nozzle 8 is different, and the amount of protrusion can be set arbitrarily within a range that satisfies the ranges of the above-described equations.

Here, the basis for deriving the conditions of the above-described equations will be described.

FIG. 5 shows the change in the decomposition rate of the chemical substance with respect to the average flow rate ut inside the reactor 5. The chemical substance targeted here is trichloroethylene, which is recognized as a carcinogenic cleaning agent. The decomposition rate mo shown on the vertical axis is shown as a relative value by dividing by the final decomposition rate mo * ((not 100%). When the average flow velocity ut in the reactor 5 is small, the turbulence in the reactor 5 is poor. When the average flow rate ut is increased as shown by an arrow-> a region in the figure, the decomposition rate may be slightly lower because the reaction may not proceed sufficiently. In this case, the reaction time is shortened and the decomposition rate is slightly reduced, and from the results of these studies, it is considered that the average flow rate ut in the reactor is optimally in the range of the above equation (2).

FIG. 6 shows the average reaction (residence) time tr in the reactor 5 by changing the length of the reactor 5 in the flow direction under the condition that the average flow velocity ut in the reactor 5 is constant.
FIG. 4 is a diagram summarizing a tendency of a change in a decomposition rate of a chemical substance with respect to. In this case, the target chemical substance is trichlorethylene. The decomposition rate C on the vertical axis is shown as a relative value by dividing the reaction time by the decomposition rate Ce when the reaction time is assumed to be infinite (t = t∞). As you can see from this figure,
While the average reaction (residence) time tr in the reactor is short,
Although the decomposition rate increases rapidly, it becomes substantially constant at about tr ≒ 320 sec. Therefore, it can be considered that the reaction does not proceed even if the reaction time is further secured. From the above results, regarding the reaction time in the reactor,
It is determined that it is preferable to select from the range of the expression.

Also, rather than securing the reaction time in the process of once passing through a long reactor, the reactor is passed many times through a short reactor,
In other words, the reaction rate can be increased by repeatedly jetting into the reactor as a jet with cavitation. FIG. 7 shows the change in the amount of decomposition with respect to the average reaction (residence) time tr in the reactor.
A comparison is made between the case where the reactor is passed once and the case where the short reactor is repeatedly passed. The target chemical here is the pesticide thiuram. The decomposition amount shown on the vertical axis is the final decomposition amount m assuming that t = t に お け る in one pass of the decomposition amount m ′ (a method of once passing through a long reactor).
The dimension is rendered dimensionless by dividing by e '. 7 to 1
In the case of the pass method, no increase in the amount of decomposition is observed, while in the case of the method of repeatedly passing through the reactor, the amount of decomposition increases with each passage.

FIG. 8 shows the relationship between the jet flow velocity uj of the water jet at the nozzle ejection hole 14, the injection pressure Pj at the nozzle (this pressure pj is substantially equal to the discharge pressure of the plunger pump 20), and the maintenance cost (mainly a high-pressure pump). FIG. In this embodiment, a flow velocity in a range where the equipment cost does not increase rapidly, that is, a flow velocity in the range shown in the above-described equation (1) is selected. When the jet velocity uj is increased,
The injection pressure Pj also needs to be increased, and in order to ensure the same injection flow rate, the pump equipment must be large, so that the cost becomes excessively large, which is not practically desirable.

FIG. 9 shows the relationship between the solubility of gas in the water to be treated and the amount of decomposition of chemical substances. The decomposition amount m on the vertical axis is made dimensionless by dividing by the maximum value of the decomposition amount. Here, the chemical is dibutyl phthalate, an endocrine disruptor (so-called "environmental hormone"). The gas solubility α on the horizontal axis is divided by the saturation solubility αs, which is also dimensionless. As can be seen from this figure, the decomposition amount m / m * increases sharply with the increase of α / αs, reaches a maximum at α / αs ≒ 1.3, and saturates. The gas dissolved in water is the so-called bubble nucleus (Nucl
ei), which is the "seed" of cavitation. In other words, cavitation becomes more active as the amount of dissolved gas increases. In the present embodiment, the range of the above equation (4) is selected, which corresponds to the range where m / m * starts to increase rapidly and becomes almost maximum. By the way, for normal water, α / αs ≒ 1.0
3 Air is slightly supersaturated. α> α
In order to achieve s, it is necessary to forcibly blow air into water as fine bubbles or supply hydrophobic ultrafine particles partially adhering to gas (fine bubbles).

The water temperature Tw is strongly related to the power of cavitation. In the present embodiment, the temperature range represented by Expression (5) is selected. FIG. 10 is a diagram showing a change in the amount of decomposition of a chemical substance with respect to the water temperature Tw. Here, the chemical substance is dibutyl phthalate shown in FIG. The decomposition amount shown on the vertical axis is
The dimension is made non-dimensional by dividing the decomposition amount M by the maximum decomposition amount M *. From this result, it can be seen that the range of the C region on the low temperature side of Tw <15 ° C. and the B region of Tw> 85 ° C. is 0.8 or less in the decomposition amount when the chemical substance is decomposed, which is not preferable. This is because, in the region of the C region on the low temperature side where Tw <15 ° C., the viscosity and surface tension of water are large, so that the growth and shrinkage speed of bubbles are small, and the power of cavitation is lower than that of the A region in FIG. In the region B of> 85 ° C., subcooled boiling starts inside the tubular reactor 5 as shown in FIG. 11 due to local overheating. Boiling bubbles at this time are indicated by reference numeral 30. The large lump of boiling bubbles 30 as shown in FIG. 11 acts as a cushion, thereby reducing the impact of cavitation and consuming bubble nuclei in water. This indicates that the power of cavitation is reduced even under the high temperature conditions.

As shown in FIG. 12, when the nozzle 8 provided at the tip of the nozzle mount 7 is protruded toward the center of the tubular reactor 5, a large space is created upstream of the nozzle 8.
In this space, a circulating vortex 15 is generated, so that the so-called untreated ambient water, which has not been affected by the cavitation, smoothly flows into the cavitation-containing underwater jet 9. By utilizing such a naturally occurring flow field, the efficiency of reactive decomposition or sterilization can be increased without increasing power consumption.

FIG. 13 shows a nozzle shape of a water jet reactor according to another embodiment. The nozzle shown in FIG. 3 is provided with an enlarged hollow portion 13 at the outlet of the ejection hole 14 to disturb the jet blown out from the ejection hole 14 to promote cavitation, whereas the nozzle shown in FIG. The inflow portion to 14 has a steep throttle shape. By making such a shape,
A strong contraction is generated inside the ejection hole 14 so that the cavitation bubble nucleus is intermittently supplied into the ejection flow 9 at the ejection hole 14. The cavities formed in the contraction portion of the ejection hole 14 serve as bubble nuclei. The bubble nuclei flow into the underwater water jet 9, thereby promoting the cavitation of the underwater water jet 9.

[0043]

As described above, according to the present invention, it is possible to provide a water jet reactor capable of reliably obtaining a sterilizing effect and a purifying effect. In this case, a water jet with well-developed cavitation can be continuously generated in the reactor.

In addition, this makes it possible to perform the decomposition and sterilization of harmful chemical substances in the reactor with high efficiency, and to shorten the decomposition and sterilization processing time.
In addition, the present invention can be applied to water bodies that are contaminated by harmful chemical substances and harmful bacteria.

Further, it is possible to arbitrarily provide a large-scale reactor or a small-scale reactor, and since large-scale equipment is not required, waste of energy can be suppressed. Energy efficiency can be improved in combination with efficiency and sterilization efficiency.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a water jet reactor according to an embodiment of the present invention.

FIG. 2 is a diagram showing a tubular reactor and a flow state in FIG. 1;

FIG. 3 is a model diagram of the nozzle in FIGS. 1 and 2;

FIG. 4 is a model diagram particularly showing a mounting portion of a nozzle in FIG. 3;

FIG. 5 is a characteristic diagram showing a relationship between an average flow rate and a decomposition rate of the water jet reactor according to the embodiment of the present invention.

FIG. 6 is a characteristic diagram showing a relationship between an average reaction (residence) time in a reactor and a decomposition rate of the water jet reactor according to the embodiment of the present invention.

FIG. 7 is a characteristic diagram showing a relationship between an average reaction (residence) time in a reactor and a decomposition rate of a water jet reactor according to another embodiment of the present invention.

FIG. 8 is a characteristic diagram showing a relationship between a jetting speed and a jetting pressure of the water jet reactor according to the embodiment of the present invention.

FIG. 9 is a characteristic diagram showing a relationship between a gas solubility and a decomposition rate of the water jet reactor according to the embodiment of the present invention.

FIG. 10 is a characteristic diagram showing a relationship between a water temperature and a decomposition amount of the water jet reactor according to the embodiment of the present invention.

FIG. 11 is an explanatory diagram showing a hydrodynamic behavior in the water jet reactor according to the embodiment of the present invention.

FIG. 12 is an explanatory diagram showing a hydrodynamic behavior in a water jet reactor according to another embodiment of the present invention.

FIG. 13 is a model diagram showing a nozzle shape of a water jet reactor according to another embodiment of the present invention.

FIG. 14 is a model diagram showing a nozzle shape of a water jet reactor according to a conventional example.

[Explanation of symbols]

 5 Pipe Reactor 6 High Pressure Hose 7 Nozzle Mount 8 Nozzle 9 Underwater Water Jet 16 Overflow Pipe 17,22 Reservoir Tank 18,23 Circulation Pump 19,25 Circulation Line 20 Plunger Pump 21 Three-way Switching Valve 24 Feed Tank 26 Pump Pump 27 Pump Lifting line 28 Contaminated raw water 29 Treated water

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazunori Fujita 3-36 Takara-cho, Kure-shi, Hiroshima Prefecture AB19 BB01 BB02 BC10 BD02 CA01 4G075 AA15 AA37 AA42 BA06 BB10 BD15 CA05 CA65 CA66 EA03 EB01 EC01

Claims (7)

[Claims] 1. A method of decomposing and / or disinfecting harmful chemical substances that melt in water and / or harmful bacteria floating in water by cavitation generated by a water jet ejected from a nozzle installed in flowing water of a reactor. A water jet reactor, wherein the average flow rate ut in the reactor is set so as to be in a range of 0.004 ≦ ut (m / s) ≦ 0.03. 2. A method of decomposing and / or disinfecting harmful chemical substances dissolved in water and / or harmful bacteria floating in water by cavitation generated by a water jet ejected from a nozzle installed in flowing water of a reactor. A water jet reactor, wherein the average residence time tr in the reactor is set to be in a range of 40 ≦ tr (sec) ≦ 320. 3. Decomposition treatment and / or sterilization treatment of harmful chemical substances melting in water and / or harmful bacteria floating in water by cavitation generated by a water jet ejected from a nozzle installed in flowing water of a reactor. In the water jet reactor, the jet flow velocity uj of the water jet spouted from the spout of the nozzle in the reactor is set to be in the range of 400 ≦ uj (m / s) ≦ 1600. Water jet reactor. 4. Decomposition treatment and / or sterilization treatment of harmful chemical substances melting in water and / or harmful bacteria floating in water by cavitation generated by a water jet ejected from a nozzle installed in flowing water of a reactor. In the water jet reactor, the gas solubility is 0.80 ≦ α / αs ≦ 1.30 (where α is the dissolved amount of gas, αs is the saturated dissolved amount of gas)
A water jet reactor characterized in that the amount of dissolved gas in the contaminated raw water is set so as to fall within the range described above. 5. A method for decomposing and / or disinfecting harmful chemical substances dissolved in water and / or harmful bacteria floating in water by cavitation generated by a water jet ejected from a nozzle installed in flowing water of a reactor. A water jet reactor, wherein a water temperature in the reactor tube is set within a range of 15 ≦ Tw (° C.) ≦ 85. I do. Also 6. A method for decomposing and / or disinfecting harmful chemical substances melting in water and / or harmful bacteria floating in water by cavitation generated by a water jet ejected from a nozzle installed in flowing water of a reactor. A water jet reactor, wherein the tip of the nozzle is projected toward the center of the reactor so that a circulating vortex is generated upstream of the tip of the nozzle. 7. A harmful chemical substance that melts in water and / or a harmful germ suspended in water is subjected to decomposition treatment and / or sterilization treatment by cavitation generated by a water jet ejected from a nozzle installed in flowing water of the reactor. In a water jet reactor, the following (1)
A water jet reaction apparatus, wherein processing conditions including at least two of the conditions (5) to (5) are set. (1) The average flow rate ut in the reactor is set in the range of 0.004 ≦ ut (m / s) ≦ 0.03. (2) The average residence time tr in the reactor is set in the range of 40 ≦ tr (sec) ≦ 320. (3) The jet flow velocity uj of the water jet spouted from the spout of the nozzle in the reactor is set in the range of 400 ≦ uj (m / s) ≦ 1600. (4) Gas solubility: 0.80 ≦ α / αs ≦ 1.30 (where α: dissolved amount of gas, αs: saturated dissolved amount of gas)
Set to the range. (5) The water temperature in the reactor tube is set within a range of 15 ≦ Tw (° C.) ≦ 85.