JPH09122641A - Reaction apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the treatment of oxidative decomposition of organic substances efficiently using an ultraviolet lamp in combination with an oxidizing agent. SOLUTION: In an apparatus equipped with a reaction vessel 2, an inner cylinder 3 which is arranged in the reaction vessel and opened at both ends, an axial-flow agitator 4 with its impeller 6 part arranged in the inner cylinder, and an ultraviolet lamp 7 which is arranged between the inner cylinder and the inner wall of the reaction vessel and placed in a light-transmitting and waterproof jacket, raw water introduced into the reaction vessel is mixed with an oxidizing agent and irradiated with ultraviolet light while the water being circulated in the reaction vessel by an axial-flow pump composed of the inner cylinder and the axial-flow agitator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reaction apparatus for oxidizing and decomposing organic substances by using ultraviolet rays and an oxidizing agent in combination.

[0002]

2. Description of the Related Art A method using both an ultraviolet ray and an oxidizing agent is a combination of the action of irradiating the water to be treated with ultraviolet rays to excite / cut the binding molecules of organic substances by the energy of the ultraviolet rays and the oxidizing action of an oxidizing agent. Since it does not damage the base material of precious metals because it does not have residual salts and it decomposes a small amount of solvent that cannot be removed by the adsorption method, for example, pure water manufacturing process and IC manufacturing. It is used in the process of reprocessing wash water in the case of.

[0003]

However, since the UV lamp is housed in a quartz jacket, it is fragile (although not so strong), and the water to be treated is kept as static as possible. It was often processed in the state. Therefore, the reaction rate is slow, and in order to compensate for it, the output of the ultraviolet lamp must be increased, the amount of the oxidizing agent added must be increased, and the remaining oxidizing agent also increases. If there is a large amount of the oxidizing agent remaining in the treated water after the treatment, there is a high possibility that the activated carbon, the reverse osmosis membrane, the ultrafiltration membrane or the like will be destroyed in the treatment in the next step.

A method using a combination of ultraviolet rays and an oxidizing agent is
It is also considered to be applied to large-scale treatment such as sewage treatment water, industrial wastewater treatment water, purified water treatment water, and irrigation water, but in reality it is not so strong because the UV lamp and jacket are not so strong in strength. Not used. Moreover, depending on the nature of the water to be treated, in static treatment, the organic matter in the water to be treated absorbs the amount of effective ultraviolet rays, or the effective ultraviolet rays are reduced due to the obstruction of ultraviolet ray transmission due to suspended substances in the water to be treated. There was a drawback that it decreased.

It is an object of the present invention to provide a reactor capable of efficiently oxidizing and decomposing an organic substance while using an ultraviolet lamp and an oxidizer together.

[0006]

In the reactor of the present invention,
Of the reaction tank, the inner cylinder body having both ends opened which is arranged in the reaction tank, the axial flow agitator in which the impeller portion is arranged in this inner cylinder body, the inner cylinder body in the reaction tank and the reaction tank inner wall An ultraviolet lamp housed in a translucent jacket disposed between them, and an oxidizing agent is added to the water to be treated introduced into the reaction tank, and it is composed of an inner cylinder and an axial flow agitator. The treated water is treated while being circulated by an axial flow pump.

The reaction tank may have any shape other than a cylindrical shape such as a cylindrical shape or a rectangular tube shape, and the reaction tank may have a vertical shape or a horizontal shape. The reaction tank may have an inlet for the water to be treated and an outlet for the treated water that has been treated so that a gas phase is formed in the upper portion of the reaction tank. The inlet and the outlet are arranged according to the circulation direction of the treated water in the reaction tank, and the treated water introduced from the inlet is discharged without being treated, that is, a so-called short circuit is less likely to occur. To be done.

The inner cylindrical body is a cylindrical body having both ends opened and is arranged vertically, horizontally or obliquely in the reaction tank, but it is preferable to arrange it along the longitudinal axis of the reaction tank. The length and diameter of the inner cylinder are the size of the reaction tank and the impeller (impeller).
The size of the water, the properties of the water to be treated, and the like are taken into consideration so that the water to be treated is circulated most efficiently.

The axial-flow stirrer comprises a motor, a shaft and an impeller portion fixed to the tip of the shaft. The motor is composed of an electric motor and is arranged outside the reaction tank. The position of the motor is arranged above, on the side of the reaction tank or on the bottom side of the reaction tank depending on the arrangement of the inner cylinder. The shape of the impeller is such that the desired axial flow is produced most efficiently.

Mainly 254 nm as an ultraviolet lamp
For example, a straight-tube low-pressure mercury lamp that emits ultraviolet rays of the wavelength is used, and each lamp is housed in a transparent straight-tube waterproof jacket. The lamp is preferably arranged in parallel with the inner cylinder between the inner cylinder in the reaction tank and the inner wall of the reaction tank. The number and output of ultraviolet lamps are selected according to the properties of the water to be treated, the amount to be treated, and the like.

As the oxidizing agent, hydrogen peroxide, ozone, sodium hypochlorite, etc. can be used. These oxidizing agents are added in the bottom of the reaction tank or in the inner cylinder, but the place of addition is not limited to these.

In order to control the added amount of the oxidizing agent, an ORP (oxidation-reduction potential) electrode is arranged in the reaction tank, the ORP potential of the water to be treated is detected, and the pump and valve for supplying the oxidizing agent are controlled. You may do it.

[0013]

1 and 2, a reactor 1 of the present invention has a vertical cylindrical reaction tank 2, and a cylindrical body having upper and lower ends opened at the center of the reaction tank 2. The inner cylindrical body 3 consisting of is arranged vertically. The bell mouth 3a is provided in the opening of the cylindrical body for the purpose of improving the efficiency of inflow and discharge of the water to be treated.
Is attached. An impeller 6 fixed to the lower end of the shaft body 5 of the axial flow stirrer 4 is arranged in the inner cylindrical body 3, and an upper end of the shaft body 5 is an electric motor (not shown) arranged outside the reaction tank 2. Are linked to.

A plurality of straight tube type ultraviolet lamps 7 are arranged in parallel with the inner cylindrical body 3 between the inner cylindrical body 3 and the inner wall of the reaction tank 2. Each of the ultraviolet lamps 7 is made of waterproof quartz. It is housed in a straight-tube jacket. In addition, 8 is an inlet for raw water (treated water), 9 is an outlet for treated water (treated water), 10 is a liquid surface of the treated water, 11 is an oxidant supply port, 12
Is a mounting portion of the ORP electrode, and 13 is a gas outlet when a gas such as ozone is used as an oxidant.

The water to be treated is introduced into the reaction tank 2 through the inlet 8, while the oxidant is supplied to the water to be treated through the oxidant supply port 11. The water to be treated circulates as shown by the arrow by the operation of the axial flow pump composed of the inner cylinder 3 and the axial flow stirrer 4, and is subjected to ultraviolet ray reaction treatment by being irradiated with ultraviolet rays from the ultraviolet ray lamp 7. .

That is, 1) an oxidation reaction of an organic substance by an oxidant, 2) a strong oxidization of OH radicals in the vicinity of the UV lamp by absorbing the 254 nm wavelength UV emitted from the UV lamp by the oxidant. A substance is formed, and this OH radical causes an oxidation reaction, 3) the ultraviolet ray excites / decomposes the organic substance-binding molecule, and these 1) ~
The organic substance is oxidatively decomposed by the synergistic action of 3).

Further, since the water to be treated is agitated by the axial flow pump, the oxidant is easily dissolved in the water to be treated, and the water to be treated is circulated by the axial flow pump to form a boundary film around the ultraviolet lamp. Since it is constantly updated, the above 1) ~
The reaction of 3) is further promoted.

Further, the disposed ORP electrode monitors the treatment state of the organic substance of the water to be treated at the ORP potential, and a pump or valve (not shown) for supplying an oxidant so that the water to be treated has a predetermined ORP potential. Is controlled so that the oxidative decomposition of the water to be treated is maintained at a constant standard, and the residual concentration of the oxidant is kept to a minimum.

FIG. 3 shows another embodiment of the reactor of the present invention, in which the circulation direction of the water to be treated is opposite to that in FIG. The same members as those in FIG. 1 are designated by the same reference numerals. In this reaction device 20, the oxidant is supplied into the inner cylindrical body 3. In addition, in the apparatus of FIG. 1 and FIG.
May be disposed on the bottom side of the reaction tank 2, and in this case, since the gas phase portion 14 is not present on the bottom side, the shaft body 5 can be shortened,
The shake of the shaft body 5 can be reduced.

FIG. 4 shows still another embodiment of the reaction apparatus of the present invention. The same members as those in FIG. 1 are designated by the same reference numerals. In this reaction apparatus 30, the reaction tank 2 is placed horizontally, and the axial flow stirrer 4 is arranged on the side of the reaction tank 2. Also in this case, the shaft body 5 can be shortened and the shake of the shaft body 5 can be reduced.

[0021]

【Example】

<Conditions> Reaction tank as shown in FIG. 1, height: 2 m, diameter: 0.
5 m, capacity: 560 liters, ultraviolet lamp: low pressure mercury lamp 65 W x 10, lamp jacket: quartz, impeller diameter of axial stirrer: 10 cm, inner cylinder diameter:
11 cm, the length of the inner cylinder: 1.5 m, and the rotation speed of the axial flow stirrer: 200 rpm were made. In this reaction tank, pure water and isopropyl alcohol were added at a TOC (total organic carbon) concentration of 5
Introduce 300 liters of water added to 0 mg / liter as treated water (raw water), and supply hydrogen peroxide (H ₂ O ₂ ) as an oxidant to this to be 2.5 times the total required amount of oxidation. It was then batch processed.

<Example 1> FIG. 5 shows the relationship between the dose of ultraviolet rays and the TOC concentration and the residual hydrogen peroxide concentration. At the same time, the results when the axial stirrer (axial pump) is not operated are also shown. From this result, the TOC is much more efficiently decomposed when it is circulated by using an axial flow pump as in the present invention than when it is not circulated, and hydrogen peroxide is also consumed according to its decomposition rate. I understand that.

<Embodiment 2> Next, FIG. 6 shows the relationship between the UV irradiation amount and the TOC concentration in the case where the number of revolutions of the axial stirrer was changed within the range of 0 to 400 rpm under the above conditions. From this result, if the rotation speed of the axial stirrer is increased, T
It can be seen that although the decomposition efficiency of OC is improved, the treatment effect hardly changes at a certain rotation speed (300 rpm under the above conditions) or more.

<Embodiment 3> In the processing under the above conditions,
FIG. 7 shows the relationship between the UV irradiation dose, the TOC concentration, the ORP potential, and the residual hydrogen peroxide concentration. O from this result
If the RP potential (200 mV under the above conditions), the TOC
It can be seen that the decomposition efficiency of TOC is improved because oxidative decomposition is also performed and hydrogen peroxide does not remain.

<Example 4> Further, under the above conditions, a continuous treatment of continuously supplying water to be treated was carried out.
FIG. 8 shows changes with time of the ORP potential, the TOC concentration at the inlet, the TOC concentration at the outlet, and the residual hydrogen peroxide concentration in this case. From this result, a certain ORP potential (under the above conditions, 20
At 0 mV), it was found that TOC was also oxidatively decomposed, hydrogen peroxide was not left, and TOC decomposition efficiency was improved.

[0026]

According to the present invention, since the treated water is circulated by the axial flow pump disposed in the reaction tank to perform the dynamic treatment, the treated sewage water using the ultraviolet lamp and the oxidant together,
Large-scale treatment of industrial wastewater treatment water, purified water treatment water, and irrigation water is possible.

According to the present invention, the reaction tank becomes a complete mixing tank, and it is possible to prevent a so-called short circuit in which the water to be treated is discharged without being treated. Further, since the treated water is circulated in the vicinity of the ultraviolet lamp by the axial flow pump, the required amount of ultraviolet rays is sufficiently irradiated to the treated water, and the oxidant is sufficiently mixed with the treated water by the axial flow pump. . Further, by circulating the water to be treated, the boundary film around the ultraviolet lamp is constantly renewed, and the ultraviolet rays and the oxidizing agent effectively perform an optical reaction to generate OH radicals, so that the oxidative decomposition efficiency of the organic substance is improved.

Further, since the impeller portion of the axial stirrer which constitutes the axial pump is arranged inside the inner cylinder and is isolated from the ultraviolet lamp, even if the impeller shakes or breaks, the ultraviolet lamp is damaged. There is no fear of giving. In addition, when the inner tube forming the axial flow pump and the ultraviolet lamp are parallel to each other, the water to be treated flows along the axial direction of the ultraviolet lamp and the irradiation efficiency of ultraviolet rays is good.

Further, in the apparatus of the present invention, since the axial flow pump, which is a power source for circulating the water to be treated, is arranged in the reaction tank, the resistance during circulation is small and the stirring power is also small.

Further, if an ORP electrode is arranged in the reaction tank so that the ORP potential of the water to be treated can be detected and the supply amount of the oxidizing agent can be controlled, the oxidizing agent can be reduced and the residual oxidizing agent can be kept at the minimum concentration. Since it can be maintained at,
Even if a reverse osmosis membrane or an ultrafiltration membrane is used, they will not be destroyed.

Further, the device of the present invention is easy to design,
For example, the performance as designed can be obtained by determining the stirring power per unit volume of the reaction tank and the number of circulation of the water to be treated, etc., and a large-scale device can be manufactured based on the data in a small-scale device. However, the desired performance can be obtained, and so-called scale-up is easy.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a reaction apparatus according to the present invention.

2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a diagram showing another embodiment of the reaction device according to the present invention.

FIG. 4 is a view showing still another embodiment of the reaction device according to the present invention.

FIG. 5 is a diagram showing a relationship among an ultraviolet irradiation dose, a TOC concentration, and a residual hydrogen peroxide concentration.

FIG. 6 is a diagram showing the relationship between the rotational speed of an axial-flow stirrer and the TOC concentration.

FIG. 7 is a diagram showing a relationship among an ultraviolet irradiation dose, an ORP potential, a TOC concentration, and a residual hydrogen peroxide concentration.

FIG. 8 is a diagram showing changes in ORP potential, TOC concentration, and residual hydrogen peroxide concentration in the case of continuous treatment.

[Explanation of symbols]

 1 Reactor 2 Reaction tank 3 Inner cylinder 4 Axial flow stirrer 5 Shaft 6 Impeller 7 Ultraviolet lamp 8 Raw water (treated water) inlet 9 Treated water (treated water) outlet 10 Treated water level 11 Oxidant supply port 12 ORP electrode mounting part 13 Gas discharge port 20 Reactor 30 Reactor

Claims (2)

[Claims] 1. A reaction tank, an inner cylinder body having both ends opened, which is arranged in the reaction tank, an axial flow agitator in which an impeller portion is arranged in the inner cylinder body, and an inner cylinder body in the reaction tank. And an inner wall of the reaction tank, the ultraviolet lamp being housed in a light-transmitting and waterproof jacket, and an oxidizing agent added to the water to be treated introduced into the reaction tank. And an axial-flow stirrer are used to circulate the water to be treated in the reaction tank by an axial-flow pump, and subject the water to be treated to an ultraviolet reaction treatment. 2. The reaction apparatus according to claim 1, wherein an ORP electrode is arranged in the reaction tank, and the supply amount of the oxidant is controlled based on the ORP potential detected by the ORP electrode.