JPH11675A - Ozone contact reaction tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ozone contact reaction tank utilizing the ozone contact reaction in which the photocatalyst reaction of radiation, ultraviolet ray, laser beam or the like is used. SOLUTION: In an ozone contact reaction tank, substances to be removed in water to be treated are removed by reaction with ozone and ozonized gas 3 is blown into water 1 to be treated ion flowing into from the upper section of an inner tube 5 and the water 1 to be treated is flowed down in the inner tube 5 together with ozonized gas, and then flowed up in a space between the inner tube 5 and an outer tube 6 encircling the inner tube, and also anyone of ultraviolet ray, radiation or laser beam is emitted from an emission device 12 provided in an overflow tank 11a into oxidized water in a process in which the water to be treated is overflowed into the overflow tank 11a so set as to encircle the outer tube 6 on the upper section of the outer tube and remove substances to be removed such as hard-to-react substances in the water 1 to be treated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ozone contact reaction tank used for water treatment such as water purification treatment, wastewater treatment, industrial wastewater treatment and the like. More specifically, it dissolves ozone in water to be treated and makes it difficult to react with ozone. The present invention relates to a double tube type ozone contact reaction tank that performs an oxidation reaction treatment with a substance to be removed such as a substance.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional double tube type ozone contact reactor, which is described in, for example, US Pat. No. 4,572,821. In the figure, 1 is the water to be treated, 2 is the inflow pipe for the water to be treated, 3 is the ozonized gas, 4 is the pipe for blowing the ozonized gas, 5 is the inner pipe which is the tip of the inflow pipe 2 for the treated water, 6
Is an outer tube covering the inner tube 5, 7 is treated water oxidized by ozonized gas, 8 is a treated water outflow tube, 9 is exhaust gas discharged by the oxidation reaction, 10 is an exhaust gas take-out tube, 11
Is an overflow tank for receiving oxidized water by ozone flowing from the upper end of the outer pipe 5.

This double tube type ozone contact reaction tank is mainly composed of a vertical cylindrical outer tube 6 having a bottom and a vertical cylindrical inner tube 5 inserted into the outer tube 6 and having an open bottom. The space inside the inner tube 5 and between the inner tube 5 and the outer tube 6 is an ozone contact reaction tank. The ozonized gas 3 blown from the ozonized gas blowing pipe 4 is sent from an ozone generator. The ozonized gas 3 flows through the ozonized gas blow-in pipe 4 provided above the inner pipe 5 by natural flow or by a pump or the like.
It is blown in. The water 1 to be treated becomes a gas-liquid two-phase flow along with the ozonized gas 3 and descends in the inner pipe 5, during which ozone is dissolved in the water 1 to be treated with high efficiency. Then, the to-be-treated water 1 and the ozonized gas 3 that has not been dissolved completely rises in the space between the inner pipe 5 and the outer pipe 6 via the lower end opening of the inner pipe 5. In this way, while passing through the inner tube 5 and the space between the inner tube 5 and the outer tube 6, the substance to be removed, mainly organic matter, is oxidatively decomposed and removed by the dissolved ozone. The treated water 1 is caused to flow from the upper part of the outer pipe 1 into the overflow tank 11 and then flows out of the tank through the treated water outflow pipe 8 provided in the overflow tank 11. Further, the exhaust gas 9 in the overflow tank 11 is exhausted via an exhaust gas take-out pipe 10.

[0004] Further, the ozone contact reaction tank is configured so that the required residence time can be obtained in order to secure the time required for the reaction between the ozone dissolved in water and the substance to be removed. Therefore, when the substance to be removed is a difficult-to-react substance, a long stagnation time required for the reaction is required, so that a contact tank having a large internal volume is formed.

[0005] Further, such a double-tube type ozone contact reaction tank usually has a circular cross-sectional shape for the sake of simplicity in construction and balance between the water levels of the preceding and following processes, and most of the ground section is grounded. It is buried inside.

[0006] In general, the reaction between ozone and an object to be removed such as soluble organic matter in the water to be treated is a direct reaction with ozone and an indirect reaction with OH radicals (hydroxyl group, -OH) generated by decomposition of ozone. Are classified into two types. O
H radicals have a higher oxidation-reduction potential than ozone molecules and can oxidize hardly decomposable substances to be removed that cannot be treated by direct reaction with ozone. Therefore, an ozone contact reaction tank provided with auxiliary means for promoting the generation of OH radicals and increasing the oxidizing power of ozone is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-228496. This ozone contact reaction tank performs an oxidation reaction (ozone reaction) with ozone while irradiating the water to be treated with ultraviolet rays, performs an ozone reaction while contacting with a catalyst, or performs an ozone reaction while injecting hydrogen peroxide. A so-called accelerated ozone reaction treatment method.

[0007]

However, in the double tube type ozone contact reaction tank shown in FIG. 5, most of the removal of the substance to be removed from the treated water is performed by direct reaction with ozone. Therefore, when the object to be removed is a hardly decomposable substance, it is necessary to lengthen the residence time of the water to be treated in order to lengthen the oxidation treatment time. There is a disadvantage that the area and the construction cost increase.

On the other hand, the accelerated oxidation treatment method for enhancing the oxidizing power of ozone by promoting the generation of OH radicals has the following problems. First, when ultraviolet rays and ozone are used together, the irradiated ultraviolet rays are absorbed by the water to be treated in proportion to the depth (thickness) of the water to be treated. Therefore, the ultraviolet rays contributing to the generation of OH radicals become a very small part of the total irradiation amount, and have a disadvantage that the generation efficiency of OH radicals is poor.

When a catalyst and ozone are used together,
There is a problem in that the efficiency of OH radical generation is low, and that the contact time between the catalyst and the water to be treated containing ozone must be lengthened, thereby increasing the volume of the apparatus. Furthermore, when OH radicals are generated by a photocatalytic reaction using ultraviolet light, a catalyst and ozone in combination, most of the irradiated ultraviolet light is absorbed by the water to be treated, so that the generation efficiency of OH radicals is low. However, it is not economical and has a drawback that the volume of the apparatus is large.

In addition, when hydrogen peroxide and ozone are used in combination, the cost of injecting hydrogen peroxide increases, and the use of hydrogen peroxide is currently approved in domestic water purification treatments from the viewpoint of safety. Therefore, there is a disadvantage that the oxidation treatment in the water purification treatment cannot be effectively performed.

The present invention has been made in view of the above problems, and has as its object to provide an ozone contact reaction tank using a photocatalytic reaction such as radiation, ultraviolet light, and laser light. Further, it is an object of the present invention to provide an ozone contact reaction tank that can reduce the size of the ozone contact reaction tank and promote the ozone contact reaction.

[0012]

Means for Solving the Problems The present invention has been made to achieve the above object, and the invention of claim 1 has the following features.
The ozonized gas is blown into the water to be treated flowing from the upper part of the inner pipe, and the water to be treated is lowered in the inner pipe together with the ozonized gas, and then rises in the space between the inner pipe and the outer pipe surrounding it. In the process of removing, while removing the substance to be removed from the water to be treated by reacting with ozone, and flowing the water to be treated into an overflow tank provided so as to surround the upper part of the outer tube, In the ozone contact reaction tank that flows out from the treated water outflow pipe provided in the overflow tank, in the process in which the water to be treated overflows from the upper part of the outer pipe to the overflow tank, An ozone contact reaction tank characterized in that an irradiation device for irradiating any one of ultraviolet light, radiation and laser light to the water to be treated is provided in the overflow tank. In the present invention, when the water to be treated overflowing from the upper end of the outer tube flows down in a thin layer, the ultraviolet light,
Irradiation with radiation or laser light reduces the absorption of light by the water to be treated, and the irradiated light effectively contributes to the generation of OH radicals. The generated OH radical is
It reacts with difficult-to-react substances that cannot be removed by ozone dissolved in the water to be treated, and can be decomposed and removed by an oxidation reaction.

[0013] The invention according to claim 2 is the ozone contact reaction tank according to claim 1, wherein the water to be treated overflows from the upper portion of the outer tube to the overflow tank. On the outer wall of the outer tube in a portion surrounded by the overflow tank, the effluent is spread or narrowed from the upper end where the water to be treated overflows so that the treated water flows down in a thin layer on the outer wall surface of the outer tube. An ozone contact reaction tank characterized by having an inclination. In the present invention, by having such a shape, the water to be treated that flows down from the upper end of the outer pipe into the overflow tank is the flowing water flowing on the outer wall surface,
Since it can be more reliably formed into a thin layer, the amount of absorption of ultraviolet rays by the water to be treated upon irradiation with ultraviolet rays is reduced, and OH radicals due to ultraviolet rays are efficiently generated.

According to a third aspect of the present invention, there is provided an ozone contact reaction tank according to the first or second aspect, wherein titanium oxide, zinc oxide,
An ozone contact reaction tank characterized by being coated with a catalyst made of at least one of tungsten trioxide, a nickel salt and a cobalt salt, or one or more materials. According to the present invention, OH radicals can be generated using a photocatalytic reaction. The amount of light absorbed into the water to be treated can be reduced, the amount of light reaching the catalyst surface increases, and the amount of OH radicals generated by the photocatalytic reaction increases. Done.

According to a fourth aspect of the present invention, in the ozone contact reaction tank according to the first, second or third aspect, irradiation of ultraviolet light, radiation or laser light irradiated from an irradiation device provided in the overflow tank. An ozone-contacting reaction tank characterized in that a drop is given to flowing water flowing in a thin layer form along the outer wall surface of the outer pipe from the upper end of the outer pipe surrounded by the overflow tank in order to enlarge the area. It is. According to the present invention, the generation of OH radicals by the photocatalytic reaction can be efficiently performed, so that the performance of removing difficult-to-react substances can be further improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ozone contact reaction tank according to the present invention will be described below with reference to the drawings. 1 to 4 are cross-sectional views schematically showing the present embodiment, and the same portions are denoted by the same reference numerals.

(Embodiment 1) FIG. 1 shows an embodiment of an ozone contact reaction tank according to the present invention. In the figure, 1 is the water to be treated, 2 is the inflow pipe for the water to be treated, 3 is the ozonized gas, 4 is the pipe for blowing the ozonized gas, 5 is the inner pipe which is the tip of the inflow pipe 2 for the water to be treated, and 6 is the inner pipe Outer tube covering 5, 7
Is a treated water, 8 is a treated water outflow pipe, 9 is an exhaust gas, 10 is an exhaust gas take-out pipe, 11a is an overflow tank surrounding an upper portion of the outer pipe 6 where water to be treated overflows, and 12 is an inner wall of the overflow tank 11a. It is an irradiation device provided. The irradiation device 12 is disposed in an overflow tank 11a of a double tube type ozone contact reaction tank, and irradiates any of ultraviolet light, radiation, and laser light. Inner tube 5 and outer tube 6
Is a cylindrical shape, and the irradiation device 12 is preferably an ultraviolet irradiation device because it is easy to fill the overflow tank 11a with ultraviolet light.

The double tube type ozone contact reaction tank of this embodiment comprises a vertical cylindrical bottomed outer tube 6, a vertical cylindrical inner tube 5 inserted into the outer tube 6 and having an open bottom. , Outer tube 6
An overflow tank 11a surrounding the upper part of the container, an irradiation device 12 provided in the overflow tank 11a, and an ozonized gas blowing pipe 4 inserted into the inner pipe 2 are constituted. Inside the inner tube 5,
The space between the inner tube 5 and the outer tube 6 is an ozone contact reaction tank. The ozonized gas blown from the ozonized gas blowing pipe 4 is sent from an ozone generator (not shown). The ozone generator generates an ozonized gas 3 in which at least a part of oxygen contained in a gas sent from the outside is ozone. The ozonized gas 3 is blown into the to-be-treated water 1 sent from the to-be-treated water inflow pipe 2 by a natural flow or by a pump or the like through an ozonized gas blowing pipe 4 provided at an upper portion of the inner pipe 5. The water 1 to be treated becomes a gas-liquid two-phase flow along with the ozonized gas 3 and descends in the inner pipe 5, during which ozone is dissolved in the water 1 to be treated with high efficiency. And
The to-be-treated water 1 and the ozonized gas 3 that has not been completely dissolved rise in the space between the inner pipe 5 and the outer pipe 6 via the lower end opening of the inner pipe 5. The oxidized water flowing from the upper end of the outer tube 6 is irradiated with ultraviolet rays from the irradiation device 12 to generate OH radicals in the oxidized water and oxidize the hardly reactive substance by the oxidizing action of the OH radicals. It has been decomposed and removed. The oxidized water flowing from the upper end of the outer pipe 6 is supplied to the overflow tank 1
The head L falls in a thin layer at 1a, and the head L is maintained to such an extent that the running water can be sufficiently irradiated with ultraviolet rays. The irradiation device 12 irradiates the thin layer of flowing water with ultraviolet rays to generate OH radicals and quickly react with the hardly-reactive substances in the water to be treated. Can be oxidatively decomposed.
Then, the water to be treated 1 is caused to flow from the upper portion of the outer pipe 6 into the overflow tank 11a, and flows out of the tank from the treated water outflow pipe 8 provided in the overflow tank 11a. Further, the exhaust gas 9 in the overflow tank 11a is exhausted via the exhaust gas take-out pipe 10.

As described above, in the present embodiment, while the water to be treated in which the ozonized gas is dissolved passes through the inner pipe 5 and the space between the inner pipe 5 and the outer pipe 6, the water to be treated is The substances to be removed, mainly organic substances, are decomposed and removed by an oxidation reaction by the dissolved ozone and the generated OH radicals.
Further, ultraviolet light or the like is applied to the thin layer of flowing water flowing from the upper end of the outer pipe 6 into the overflow tank 11b, thereby generating OH radicals and decomposing the hardly reactive material by an oxidation reaction. As described above, the object to be removed in the water to be treated is decomposed by the oxidation reaction treatment with ozone, and then the thin film water flowing over is irradiated with the ultraviolet light from the irradiation device 12 so that the water to be treated with the ultraviolet light is treated. As the amount of absorption into 1 can be reduced,
Oxidation by OH radicals enables efficient removal of hardly reactive substances. Needless to say, it is obvious that the oxidation reaction treatment with ozone sterilizes, removes color, removes odors, removes iron, removes manganese, and the like in the treated water.

(Embodiment 2) FIG. 2 is a sectional view showing an outline of another embodiment of the present invention. In the embodiment of FIG.
In addition to the embodiment of FIG. 1, a tapered outer wall 13 is formed on the outer wall of the outer pipe 6 surrounded by the overflow tank 11 b, and the tapered outer wall 13 is divergent from the upper end of the outer pipe 6. The water to be treated 1 flowing from the upper end of the outer pipe 6 flows down in a thin layer form on the surface of the tapered outer wall 13 inclined in a divergent manner. Therefore, by irradiating the thin layer of flowing water with ultraviolet rays from the irradiation device 12, it is possible to efficiently generate OH radicals in the water to be treated with almost no ultraviolet rays being absorbed by the water to be treated. Oxidation by OH radicals generated by ultraviolet irradiation can efficiently remove hardly reactive substances.

(Embodiment 3) FIG. 3 is a sectional view showing an outline of another embodiment of the present invention. In the embodiment of FIG.
In addition to the embodiment of FIG. 2, a tapered outer wall 13 inclined divergently from the upper end of the outer pipe 6 surrounded by the overflow tank 11b.
Is provided with a catalyst layer 14 on the surface thereof. The catalyst layer 14
It is formed of at least one kind of catalyst such as titanium oxide, zinc oxide, tungsten trioxide, nickel salt and cobalt salt, or a mixture of one kind thereof, or a material of one or more kinds thereof. The formation of the catalyst layer 14 on the surface of the tapered outer wall 13 promotes an oxidation reaction between ozone and OH radicals and a hardly reactive substance in the water to be treated. Further, the overflow tank 1 passes from the upper end opening of the outer tube 6 through the surface of the catalyst layer 14.
By irradiating ultraviolet light from the irradiation device 12 provided in the overflow tank 11b to the thin layer water flow flowing down to 1b,
The amount of absorption of ultraviolet rays into the water to be treated 1 is reduced, OH radicals are efficiently generated, and the process of decomposing and removing hardly reactive substances by OH radicals utilizing a photocatalytic reaction is efficiently performed. The catalyst layer 14 is provided with a required head L in order to obtain sufficient contact with the water to be treated. Also, in the embodiment of FIG. 1, the same effect can be expected by forming the catalyst layer 14 on the outer wall surface of the outer tube 6.

(Embodiment 4) FIG. 4 is a sectional view showing an outline of another embodiment of the present invention. In the embodiment of FIG.
An upper end 6a of the outer tube 6 is formed with a tapered outer wall 6a that is inclined from the upper end in a narrowed shape. Other shapes are the same as those of the embodiment of FIG. 1, and thus the detailed description is omitted. The water to be treated that flows over the outer wall 6a of the outer pipe 6 flows down the outer wall 6a of the tapered outer pipe 6 that is inclined in a divergent manner as a stable thin layer water flow. By irradiating the ultraviolet rays from the irradiation device 12, the absorption of the ultraviolet rays by the water to be treated can be suppressed, and OH radicals can be efficiently generated. Processing performance can be improved.

Of course, the irradiating device 12 in the overflow layers 11a to 11c may irradiate radiation such as X-rays or a laser beam in addition to ultraviolet rays. To 11c, and its driving device, control device, and the like may be provided outside the irradiation device 12. The same applies to the case of an irradiation device that irradiates ultraviolet rays and radiation.

[0024]

As described above, according to the present invention,
The water to be treated that overflows from the upper end of the outer pipe flows down in a thin layer,
The treated water is irradiated with ultraviolet rays or the like, and OH is added to the treated water.
There is an advantage in that radicals can be efficiently generated, and a treatment for removing difficult-to-react substances can be efficiently performed on the oxidized water subjected to ozone treatment by an oxidation reaction using OH radicals.

Further, the water to be treated flowing from the upper end of the outer tube is formed into a thin layer, and a required head is provided so that the contact between the water to be treated and the catalyst layer is sufficiently performed, and the water to be treated is subjected to a photocatalytic reaction. There is an advantage that the decomposition-removal treatment by oxidation reaction of the difficult-to-react material can be effectively performed.

Further, since the treatment for decomposing and removing the hardly reactive substance of the water to be treated by the oxidation reaction is carried out with high efficiency, it is possible to reduce the size of the conventional ozone contact reaction tank, especially the shape in the depth direction. There are advantages, and there is an advantage that the construction cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an ozone contact reaction tank according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the ozone contact reaction tank according to the present invention.

FIG. 3 is a sectional view showing another embodiment of the ozone contact reaction tank according to the present invention.

FIG. 4 is a cross-sectional view showing another embodiment of the ozone contact reaction tank according to the present invention.

FIG. 5 is a perspective view showing an example of a conventional ozone contact reaction tank.

[Explanation of symbols]

 2 Intake pipe for treated water 4 Injection pipe for ozonized gas 5 Inner pipe 6 Outer pipe 6a Upper end 8 Treated water outflow pipe 10 Exhaust gas extraction pipe 11a to 11c Overflow tank 12 Irradiation device 13 Outer wall 14 Catalyst layer

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Tatsuo Takechi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd.

Claims (4)

[Claims] 1. An ozonized gas is blown into water to be treated flowing from an upper portion of an inner tube, and the water to be treated is lowered in the inner tube together with the ozonized gas. In the process of raising the inside of the space, the substance to be removed in the water to be treated is removed by reacting it with ozone, and the water to be treated flows into the overflow tank provided so as to surround the upper part of the outer tube. After flowing the water to be treated through the treated water outflow pipe provided in the overflow tank, the ozone contact reaction tank overflows the water to be treated from the upper part of the outer pipe into the overflow tank. An ozone contact reaction tank, comprising: an irradiation device for irradiating any one of ultraviolet light, radiation, and laser light to the water to be treated flowing over the water. 2. The ozone-contacting reaction tank according to claim 1, wherein in the step of flowing the water to be treated from an upper portion of the outer tube to an overflow tank, the water to be treated that flows over the outer tube is formed outside the outer tube. The outer wall of the outer tube in a portion surrounded by the overflow tank is provided with a slope diverging or narrowing from the upper end where the water to be treated overflows so as to flow down the wall surface in a thin layer. Ozone contact reactor. 3. The ozone contact reactor according to claim 1, wherein titanium oxide, zinc oxide, tungsten trioxide, nickel salt and cobalt are coated on the outer wall surface of the outer tube in a portion surrounded by the overflow tank. An ozone contact reaction tank, which is coated with a catalyst made of at least one kind of salt or at least one kind of material. 4. The ozone contact reaction tank according to claim 1, 2 or 3, wherein ultraviolet rays irradiated from an irradiation device provided in the overflow tank,
In order to enlarge the irradiation area of radiation or laser light,
An ozone contact reaction tank characterized in that a drop is given to flowing water flowing in a thin layer along the outer wall surface of the outer tube from the upper end of the outer tube surrounded by the overflow tank.