JPH05305287A - Ozone contact reaction device - Google Patents

Abstract

PURPOSE:To obtain an appropriate holding time and a high stirring effect with a drive at a little water head difference by providing an untreated water feed means which feeds untreated water to the top of an inner pipe using a downward current and a feed means which feeds an ozonized air into the inner pipe, and further, providing a static mixer outside an outer pipe. CONSTITUTION:Untreated water 23 to be supplied to a receiving tank 24 flows down spontaneously through the interior of an inner pipe 25. Then an ozonized air to be supplied from an ozone generator 27 to the upper opening of the inner pipe 25, is injected into the untreated water 23 after passage through an ozonized air feed pipe 26. In this case, if the untreated water 23 running through the inner pipe 25 is set to higher than a fixed flow speed, the ozonized air is turned to fine bubbles, then these bubbles are mixed with the untreated water 23 into a gas/liquid mixture current, and this current runs down through the downward flow path of the inner pipe 25. After that, this current reflects in an upward flow path formed between the peripheral surface of the inner pipe 25 and the internal circumferential surface of the outer pipe 29, and ascends to flow into a reaction tank 22 from the top opening of the outer pipe 29. Finally, the current is stirred by a static mixer 30 installed on the periphery of the outer pipe 29 to have its holding time prolonged.

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 apparatus which dissolves ozone in water to be treated and decomposes organic matters in the water to be treated in advanced water purification treatment, advanced sewage treatment and the like.

[0002]

2. Description of the Related Art In a conventional ozone contact reaction apparatus, for example, as shown in FIG. 2, a lateral flow contact basin of vertical detour contact in which a plurality of contact reaction tanks 1 are arranged in parallel, or as shown in FIG. ,
There is a countercurrent contact type crossflow contact pond in which a bypass 2 is arranged between contact reaction tanks 1.

Further, as shown in FIG. 4, the ozone contact reaction device is provided with an injector provided at an upper end portion of the downward pipe line 4 by supplying the inflow water 5 to the downward pipe line 4 vertically provided in the reaction tank 3. 6, a Venturi injector type in which ozone gas 7 is sucked into the inflow water 5, or as shown in FIG.
The upflow portion and the downflow portion are alternately formed inside the reaction tank 3,
For example, there is a pressurized injector system that pressurizes the ozone gas 7 against the inflow water 5 to mix them.

On the other hand, when decomposing organic substances with ozone, it is known that the removal rate is higher as the concentration of dissolved ozone is higher in the initial stage of the reaction.

[0005]

However, in the above-mentioned structure, the lateral flow type contact basin as shown in FIGS. 2 and 3 has a low ozone absorption efficiency and dissolves ozone necessary for sufficiently decomposing organic substances. There was a serious problem. Further, in the injector type as shown in FIGS. 4 and 5, although the ozone absorption efficiency is high, a large head difference (water depth of 10 m
However, there is a problem that the device becomes large.

[0006] Further, the decomposition of organic substances proceeds by the reaction with OH radicals generated by the self-decomposition of ozone, and the self-decomposition of ozone is promoted as the ozone concentration becomes higher and the stirring becomes more vigorous. However, in the above-mentioned conventional configuration, stirring of the water to be treated in which ozone is dissolved is insufficient,
There is a problem that the self-decomposition rate of ozone becomes slow and the decomposition rate of organic substances becomes small.

The present invention solves the above problems, and provides an ozone contact reaction apparatus which can be driven with a small head difference and has an appropriate residence time (at least 5 minutes or more) and an appropriate stirring effect. The purpose is to provide.

[0008]

In order to solve the above problems, the ozone contact reaction apparatus of the present invention is provided by immersing an inner tube forming a downward flow path in a reaction tank having an appropriate depth, An outer pipe is fitted to the inner pipe to form an upward flow path between the outer peripheral surface of the inner pipe and the inner peripheral surface of the reaction vessel, and an outer pipe is formed on the lower end side of the outer pipe. It is connected to the inner pipe and is connected to the inside of the reaction tank at the upper end side, and the treated water is supplied to the upper end side of the inner pipe in a downward flow and the treated water is supplied to the inner pipe. Ozonized air supply means is provided, a static mixer is provided on the outer circumference of the outer tube, and a discharge water passage portion that communicates with the bottom side of the reaction tank and forms an upward flow passage is provided.

[0009]

With the above structure, when the flow velocity of the water to be treated supplied from the treated water supply means is set to a constant value (0.5 m / s) or more, the ozonized air supplied from the ozonized air supply means becomes fine bubbles. As a result, a downward flow path in the inner pipe descends together with the water to be treated as a gas-liquid two-phase flow. Furthermore, the multiphase flow reverses and rises in the upward flow path formed between the lower end opening of the inner pipe and the outer peripheral surface of the inner pipe and the inner peripheral surface of the outer pipe on the bottom side of the reaction vessel, and It flows into the reaction tank through the upper opening. In this process, ozone is dissolved in a short time, and gas-liquid separation is performed on the liquid surface in the reaction tank.

Then, the water to be treated in which ozone is dissolved descends in the downward flow path formed between the outer peripheral surface of the outer tube and the inner peripheral surface of the reaction tank, and is agitated by a static mixer provided on the outer peripheral surface of the outer tube. The mixture is sufficiently stirred under the action, and the residence time becomes long. For this reason, the self-decomposition rate of ozone in the water to be treated is increased, and the organic matter is oxidized and decomposed with high efficiency in a short time by the direct ozone oxidation by the dissolved ozone and the oxidation action by the free radical reaction of the ozone free radicals.

Further, the water to be treated flows into the discharge water channel portion from the bottom side of the reaction tank, rises in the discharge water channel portion and flows out to the next system from the upper end opening.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the ozone contact reaction apparatus 21 has a reaction tank 22 having an appropriate depth, and a receiving tank 24 for receiving the treated water 23 is provided above the reaction tank 22 as the treated water supply means. Is provided so as to close the upper end opening of the. Further, an inner pipe 25 that is immersed in the reaction tank 22 to form a downward flow path is arranged in the vertical direction,
The upper end of the inner pipe 25 opens at the bottom of the receiving tank 24, and the lower end opens near the bottom of the reaction tank 22.

An ozonized air supply pipe 26 is opened at the upper end of the inner pipe 25 as an ozonized air supply means, and an ozone generator 27 is provided at the base end side of the ozonized air supply pipe 26. There is. Further, an exhaust ozone gas exhaust pipe 28 is opened at the top of the reaction tank 22.

Further, the outer pipe 29 is arranged so as to be fitted onto the inner pipe 25, and an upward flow path is formed between the outer peripheral surface of the inner pipe 25 and the inner peripheral surface of the outer pipe 29. A downward flow path is formed between the outer peripheral surface of the tube 29 and the inner peripheral surface of the reaction tank 22. The outer pipe 29 communicates with the inner pipe 25 at the lower end side and communicates with the inside of the reaction tank 22 at the upper end side. The diameters of the inner pipe 25 and the outer pipe 29 are set so that the flow passage cross-sectional area in the downward flow passage of the inner pipe 25 and the flow passage cross-sectional area in the upward flow passage of the outer pipe 29 have substantially the same area. ing.

A static mixer 30 is provided on the outer circumference of the outer tube 29. The static mixer 30 is formed by combining baffle plates 30a. The baffle plates are arranged so as to alternately block half of the flow passage cross section. 30a is provided. Further, the upper and lower baffle plates 30a are in a state in which the angles are different by 90 °.

A discharge water channel portion 31 is provided which communicates with the bottom side of the reaction tank 22 and forms an upward flow path, and the upper end opening of the discharge water channel portion 31 is communicated with the next system. The operation of the above configuration will be described below. The water to be treated 23 supplied to the receiving tank 24 descends in the inner pipe 25 by natural flow, and at the upper end opening of the inner pipe 25, the ozone generator 2
The ozonized air supplied from 7 is the ozonized air supply pipe 26.
And is jetted into the water 23 to be treated.

At this time, the treated water 23 in the inner pipe 25
When the flow velocity of the water is set to a constant value (0.5 m / s) or more, the ozonized air becomes fine bubbles and descends in the downward flow path inside the inner pipe 25 as a mixed phase of gas-liquid two phases together with the water 23 to be treated. To do.

The mixed-phase flow flows from the lower end opening of the inner pipe 25 to the outer peripheral surface of the inner pipe 25 and the outer pipe 2 on the bottom side of the reaction tank 22.
It rises by being turned upside down in the upward flow path formed between the inner peripheral surface of 9 and the inside of the reaction vessel 22 through the upper end opening of the outer tube 29. The ozone of the ozonized air which has become fine bubbles in this process is highly efficient for the treated water 23 for a short time (2 at a water depth of 10 m).
It dissolves in the water 23 to be treated in 0 to 40 seconds), and free radicals are generated from ozone.

Further, by making the flow passage cross-sectional area in the downward flow passage of the inner pipe 25 and the flow passage cross-sectional area in the upward flow passage of the outer pipe 29 substantially the same, The difference in specific gravity of the water to be treated 23 from the upward flow path of the pipe 29 is small (the specific gravity of the water to be treated 23 in the inner pipe 25 is slightly small), and the head loss ΔH can be greatly reduced compared to the conventional case.

The water 23 to be treated in which ozone is dissolved descends in the downward flow path formed between the outer peripheral surface of the outer tube 29 and the inner peripheral surface of the reaction vessel 22, and is provided on the outer peripheral surface of the outer tube 29. The static mixer 30 is sufficiently stirred by the stirring action and the residence time becomes long. Therefore, the treated water 2
The self-decomposition rate of ozone dissolved in 3 becomes faster, and the organic matter is oxidized and decomposed in a short time with high efficiency by the oxidation effect of the free radical reaction of ozone free radicals and the direct ozone oxidation by dissolved ozone.

Further, the water 23 to be treated flows into the discharge water passage portion 31 from the bottom side of the reaction tank 22, rises in the discharge water passage portion 31 and flows out to the next system from the upper end opening. Further, the exhaust ozone is led from the exhaust ozone gas exhaust pipe 28 to the exhaust ozone decomposing device.

[0022]

As described above, according to the present invention, a multiphase flow of water to be treated and ozonized air circulates in an upward flow path and a downward flow path formed by an inner pipe and an outer pipe, Ozone can be dissolved in water to be treated in a short time. Further, the water to be treated in which ozone is dissolved is sufficiently stirred by the stirring action of the static mixer,
Since the residence time is long, the self-decomposition rate of ozone is high, and the organic substance can be oxidatively decomposed in a short time with high efficiency by the direct ozone oxidation and the oxidation action by the free radical reaction of ozone free radicals.

[Brief description of drawings]

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

FIG. 2 is a schematic view of a conventional ozone contact reaction device.

FIG. 3 is a schematic view of a conventional ozone contact reaction device.

FIG. 4 is an overall sectional view of a conventional ozone contact reaction device.

FIG. 5 is an overall sectional view of a conventional ozone contact reaction device.

[Explanation of symbols]

 21 Ozone Contact Reaction Device 22 Reaction Tank 23 Treated Water 24 Receiving Tank 25 Inner Tube 26 Ozonized Air Supply Tube 29 Outer Tube 30 Static Mixer

Claims (1)

[Claims] 1. An inner pipe for forming a downward flow path is provided by being dipped in a reaction tank having an appropriate depth, and is fitted onto the inner pipe to form an upward flow path between the inner pipe and an outer peripheral surface thereof. In addition, an outer pipe that forms a downward flow path with the inner peripheral surface of the reaction tank is provided, and the outer pipe is connected to the inner pipe on the lower end side and to the reaction tank on the upper end side, and the upper end side of the inner pipe is connected. The inner tube is provided with a treated water supply means for supplying the treated water in a downward flow and the inner tube is provided with an ozonized air supply means for supplying the ozonized air, the outer tube is provided with a static mixer, and the reaction tank An ozone contact reaction device, characterized in that an exhaust water channel portion that communicates with the bottom side and forms an upward flow channel is provided.