JPH07275873A - U-tube type ozone reaction tank - Google Patents

Abstract

PURPOSE:To provide a U-tube type ozone reaction tank enhancing the absorbing efficiency of ozone gas with respect to water to be treated without being accompanied by scaling-up and reduced in cost. CONSTITUTION:A pressure pump 16 raising the pressure of water to be treated and a water pressure meter 17 are arranged to the inflow pipe 15 of the water to be treated flowing in a U-tube type ozone reaction tank and a throttle valve 11 adjustable in its opening degree and a water pressure meter 13 are arranged in the vicinity of the underside part of an inner pipe 6 and the opening degree of the throttle valve 13 is appropriately controlled on the basis of the pressure of the water to be treated and the water pressure of the inner pipe 6 by a control part 18. The water pressure in the inner pipe 6 is adjusted to a predetermined range on the basis of the output signal of the control part 18. The water pressure in the inner pipe 6 is set to 2.0-2.5 (kgf/cm<2>).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a U-tube type ozone reactor which is useful when applied to an ozone treatment apparatus as a method for treating water and sewage.

[0002]

2. Description of the Related Art In recent years, water pollution in rivers and lakes is advancing along with the deterioration of the water environment in urban areas, and it is only possible to combine conventional coagulation sedimentation, sand filtration and chlorine treatment into raw water for tap water. The present situation is that there are limits to the chromaticity and odor removal effects of. In particular, about 70% of the water source used as tap water in Japan depends on lake water, dam water, and river water called surface water, and these lake water and dams are actively used for biological activities associated with eutrophication. There is a musty odor or algae odor due to liquefaction. On the other hand, the organic water and ammonia nitrogen contained in various effluents flow into the river water,
It cannot be expected that these influents will be completely purified by the natural purification action of the river.

[0003] In order to deal with the deterioration of water quality of the water source due to such rapid economic growth, prechlorination is generally adopted, but trihalomethane which is an organic chlorine compound generated in the water purification process adopting prechlorination. It is known that (THM) has carcinogenicity. In order to eliminate mold odors and algae odors from such water sources and to prevent carcinogens such as trihalomethanes, an advanced water purification system that introduces ozone treatment or a combined treatment of ozone treatment and activated carbon treatment into the operation process of water purification is considered. Has been done.

Ozone gas has an action of oxidizing and removing dissolved harmful substances dissolved in water by its own strong oxidizing power, and is recently used not only for clean water but also for sewage treatment. However, since ozone treatment costs about twice as much as chlorine treatment, it is required to further enhance the treatment effect of ozone gas. Therefore, by creating innumerable minute ozone gas bubbles, the ozone treatment of water and ozone gas is increased. It is an essential requirement to improve contact efficiency and efficiently dissolve and absorb ozone gas in water.

Conventionally, as a means for increasing the contact efficiency and absorption efficiency of ozone gas, a diffuser tube type ozone reaction tank or a U-tube type ozone reaction tank is known. As an example of the air diffuser type ozone reaction tank, for example, "Ozone-utilizing water treatment technology" (Isao Soumiya, Pollution Control Technology Club, 1989)
(May, 2013), an example of a vertical counterflow type ozone reactor as shown in FIG. 3 is disclosed. That is, in this example, the partition walls 2 and 2 rising from the bottom surface inside the ozone reaction tank 1,
Partition walls 3 and 3 are provided so as to hang down from the upper surface, and the partition walls 2 and 3 separate a gas phase portion and a plurality of overflow type reaction chambers in which liquid phase portions are communicated with each other. Has been done.

An air diffuser 4.4 is provided near the inner bottom surface of each chamber.
Is disposed and ozone gas obtained from an ozone generator (not shown) is sent to the diffuser pipe 4.4, and the water to be treated and the ozone gas flowing from the inflow port 5 come into contact with each other as a counter flow as shown by arrows A and A. By doing so, the contact efficiency of the ozone gas is enhanced, and the ozone-treated water 10 flows out. An air diffuser 4.4 for forming fine ozone gas bubbles.
Is made of ceramic.

The other U-tube type ozone reaction tank is also called an injector type ozone contact tank, and as shown in FIG. 4, the inner tube 6 is arranged inside the vertically elongated ozone reaction tank 1, Ozone gas obtained by the generator 7 is fed from the upper part of the inner pipe 6 via the gas discharge pipe 8.
Then, the water to be treated and the ozone gas flowing in from the side inlet 5 of the ozone gas reaction tank 1 continuously contact as a downward flow in the inner pipe 6 to perform a predetermined ozone treatment, and the outside of the inner pipe 6 as it is. This is a method of ascending along the wall surface and then flowing out as ozone-treated water 10 from the upper part of the ozone reaction tank 1.

The ozone reactor 1 has a longitudinal length of 20.
It grows up to -30 meters, which keeps the water pressure in the inner tube 6 at a level of 2.0 to 2.5 (kgf / cm ² ). The unreacted ozone gas is sent to the exhaust ozone treatment device 9 and cleaned.

This U-tube type ozone reactor has an inner tube 6
The gas-liquid contact effect between the ozone gas and the water to be treated is enhanced by the turbulent flow generated in the step (1), and the water pressure that increases as the ozone gas flows down the inner pipe 6 promotes the dissolution of the ozone gas in water. is doing.

By using such an ozone reaction tank,
Ozone gas, which has a much stronger oxidizing power than chlorine, removes the offensive odor and chromaticity of the water to be treated and oxidizes and removes harmful substances (for the U-tube type ozone treatment device, the 2nd Annual Meeting of the Japan Ozone Society) Research Lecture Lecture No. 7
6 to 77, Toriyama et al., "Organic matter removal characteristics of U-tube type ozone contact tank").

[0011]

However, it cannot be said that the ozone reaction tank used in the above-mentioned advanced water purification system or the like has a sufficient absorption efficiency of ozone gas with respect to the water to be treated, so that the absorption efficiency decreases with time. In addition to the possibility of occurrence of the above, there is a problem that the cost is increased due to the enlargement of the device.

For example, in the air diffusion tube type ozone reaction tank shown in FIG. 3, as the treatment progresses, iron or manganese oxidized by ozone gas adheres to the surface of the air diffusion tube 4, and the air diffusion tube 4
There is a risk of causing a decrease in ozone absorption efficiency over time due to the clogging of the gas, and there is a problem that it is necessary to replace the air diffusing tube itself in response to this phenomenon. Furthermore, in order to obtain a sufficient reaction time with ozone gas, the reaction tank must be enlarged, which leads to an increase in the cost required for equipment and the like, and a large site area for installing the device is required. It is difficult to use in areas where it is difficult to secure land such as water purification plants in urban areas.

On the other hand, the U-tube type ozone reaction tank shown in FIG. 4 has an ozone dissolution efficiency improved by about 5 to 10% as compared with the diffuser tube type ozone reaction tank, and the ozone gas and the water to be treated are separated from each other. The contact time can be made longer than 5 times, and the residence time in the reaction tank can be shortened to 1/5 or less, but as described above, the water depth of the ozone reaction tank is 20 to 30 meters. Since it is growing rapidly, there is a problem that the construction work of the facility becomes more complicated than that of the air diffuser method, and further, the removal of the deposits stored in the reaction tank and the cleaning of the inside of the tank cannot be performed easily. However, even if some trouble occurs in the vicinity of the bottom of the reaction tank, it cannot be immediately treated.

Therefore, the present invention has been made in view of the above, and the absorption efficiency of ozone gas with respect to the water to be treated can be improved without increasing the size of the apparatus, the cost can be reduced, and the absorption efficiency can be lowered with time. The object is to provide a U-tube type ozone reaction tank in which no phenomenon occurs.

[0015]

In order to achieve the above object, the present invention is directed to the above-mentioned U-tube type ozone reaction tank, wherein the treated water is introduced into an inlet pipe of the treated water flowing into the ozone reaction tank. A pressure pump for increasing the water pressure and a water pressure gauge are installed, and a throttle valve with an adjustable opening and a water pressure gauge are installed near the lower part of the inner pipe to measure the water pressure of the treated water measured by the water pressure gauge. And a control unit that appropriately controls the opening degree of the throttle valve based on the water pressure of the inner pipe,
Provided is a U-tube type ozone reaction tank in which the opening of the throttle valve is adjusted so that the water pressure in the inner pipe is within a predetermined range based on the output signal of the control unit. The range of water pressure in the inner pipe is 2.0 to 2.5 (kgf / cm ² ).

[0016]

According to such a U-tube type ozone reaction tank, when the raw water as the water to be treated passes through the inflow pipe, it is pressurized to a predetermined water pressure by the pressurizing pump and then pumped to above the inner pipe. The ozone gas obtained from the ozone generator is drawn into the inner pipe together with the pressurized water to be treated, and continuously flows as a downward flow while coming into contact with and flowing down. At this time, based on the water to be treated and the water pressure in the inner pipe, an output signal that appropriately controls the opening of the throttle valve is issued from the control unit, so that the water pressure in the inner pipe is within a preset range. The opening degree of is adjusted.

The range of water pressure in the inner pipe is 2.0 to 2.0, which is almost the same as the water pressure level of a normal U-tube type ozone reaction tank.
It is set to be 2.5 (kgf / cm ² ).

By contacting the ozone gas with the water to be treated, deodorization, decolorization, oxidation and removal of ferromanganese and organic substances, sterilization, removal of algae and off-flavors are carried out, and the treated water is discharged as ozone treated water.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a U-tube type ozone reaction tank according to the present invention will be described in detail below with reference to the drawings, in which the same reference numerals are given to the same components as those of the conventional one.

In the schematic view shown in FIG. 1, 1 is a vertically long ozone reaction tank, and an inner pipe 6 is arranged inside the ozone reaction tank 1. A throttle valve 11 whose opening can be adjusted is attached near the lower side of the inner pipe 6, and the pipe diameter of the inner pipe 6 is partially reduced near the upper side of the inner pipe 6. An ozone gas injector unit 12 is formed.

As will be described later in detail, the length of the ozone reaction tank 1 in the vertical direction is about 5 to 6 meters.
20 to 3 which is the same length of the tube type ozone reaction tank
The structural feature of this embodiment is that the length of 0 meters is greatly shortened, which is substantially the same as the water depth level of a normal diffuser type ozone reaction tank.

Reference numeral 7 is an ozone generator, and 8 is a gas discharge pipe. The other end of the gas discharge pipe 8 is located at a position facing the ozone gas injector portion 12 formed near the upper portion of the inner pipe 6. Reference numeral 13 is a water pressure gauge for the inner pipe.

Reference numeral 14 is a raw water storage tank in which raw water as treated water is stored, 15 is a raw water inflow pipe, 16 is a pressure booster pump, and the raw water stored in the raw water storage tank 14 is a pressure booster pump 16 Raw water inflow pipe 1 by the driving force of
It is fed into the inner pipe 6 via 5.

A water pressure gauge 1 is provided in the middle of the raw water inflow pipe 15.
7 is provided, and the water pressure of the raw water measured by the water pressure gauge 17 and the water pressure in the inner pipe 6 measured by the inner pipe water pressure gauge 13 are input to the control unit 18. The opening degree of the throttle valve 11 is controlled by the output signal S of the control unit 18.

Reference numeral 19 denotes an ozone-treated water tank. The ozone-treated water 10 flowing out from the upper portion of the ozone reaction tank 1 is temporarily stored and then supplied to the activated carbon treatment tower or the like in the next stage.

The operation and operating principle of the U-tube type ozone reaction tank of this embodiment having the above-described structure during operation will be described below. First, as a basic operation, the raw water stored in the raw water storage tank 14 is supplied to the pressurizing booster pump 16 via the raw water inflow pipe 15, and the pressurizing booster pump 16 operates approximately 2.5 to 3.0 ( After pressurizing to (kgf / cm ² ), it is pressure-fed to the ozone gas injector section 12 via the water pressure gauge 17. Simultaneously with the above, by activating the ozone generator 7, the ozone gas obtained from the ozone generator 7 is supplied to the ozone gas injector 12 via the gas discharge pipe 8.

Then, the ozone gas is drawn from the ozone gas injector section 12 into the inner pipe 6 by the flow of the raw water pumped by the pressure booster pump 16, and flows down as a downward flow while continuously contacting the raw water, and the throttle valve 1
After passing through 1, the turbulent state is reached by hitting the bottom wall of the ozone reaction tank 1, which further enhances the contact efficiency between ozone gas and raw water.

In the above operation, the water pressure in the inner pipe 6 is 2.0 to 2.5 (kgf / cm ² ), that is, approximately the same as the water pressure level of a normal U-tube type ozone reaction tank (see FIG. 4). Held in. In this water pressure maintaining operation, the water pressure of the raw water measured by the water pressure gauge 17 and the water pressure in the inner pipe 6 measured by the water pressure gauge 13 are input to the control portion 18, so that the control portion 18 controls the throttle valve 11 to operate. This is performed by issuing an output signal S that appropriately controls the opening degree.

More specifically, the control of the water pressure in the inner pipe 6 is carried out based on the difference between the preset water pressure (WP _S ) and the water pressure measured by the water pressure gauge 13 (WP _P ).
It is carried out by adjusting the opening degree of the throttle valve 11 attached to the. That is, WP _S -WP _P = 0 ... (Opening is appropriate) WP _S -WP _P <0 ... (Increases opening) WP _S -WP _P > 0 ... (reduction of opening) is performed.

FIG. 2 shows the opening (OP) of the throttle valve 11,
It is a graph showing the relationship with WP _S -WP _P , and as shown in the figure, if WP _S -WP _P = 0, the opening of the throttle valve 11 is appropriate and the water pressure set in the inner pipe 6 is maintained. Leaning, W
If P _S -WP _P <0, the measured water pressure value is larger than the set water pressure, so the opening of the throttle valve 11 is increased by ΔOP (+ a), while if W _{P S} -WP _P > 0. Since the water pressure in the inner pipe 6 is insufficient, the opening degree of the throttle valve 11 is reduced by ΔOP (−a) to adjust to the set water pressure.

The unreacted ozone gas is sent to an exhaust ozone treatment device (not shown) and decomposed into harmless gas by well-known thermal decomposition, catalytic decomposition, soil decomposition, chemical solution cleaning treatment or activated carbon treatment again. Released into the atmosphere. That is, since ozone gas has a strong oxidizing power similar to that of fluorine and is harmful to the human body, it is indispensable to decompose the ozone gas with an exhaust ozone treatment device.

By such contact between ozone gas and raw water, deodorization, decolorization, oxidation and removal of iron-manganese and other organic substances, sterilization, algae killing, and removal of off-flavors are carried out, and then the ozone reaction tank 1 is discharged from the upper portion. Treated water 10 is ozone treated water tank 1
It is temporarily stored in 9 and prepared for the next step.

[0033]

As described in detail above, according to the U-tube type ozone reaction tank of the present invention, the water to be treated is preliminarily pressurized by the pressurizing pump before flowing into the inner pipe, and then, together with the ozone gas. A desired ozone treatment is performed by flowing downward while contacting as a downward flow in the inner pipe. Therefore, even if the water depth of the ozone reaction tank is not formed to be as long as 20 to 30 meters as in the conventional case, the range of the water pressure in the inner tube is 2.0 to 2.0, which is almost the same as the water pressure level of the normal U-tube type ozone reaction tank.
Since it is maintained at 2.5 (kgf / cm ² ), the ozone gas absorption efficiency for the water to be treated can be increased without increasing the size of the apparatus. Further, since a normal air diffuser is not used, it is possible to prevent a decrease in absorption efficiency with time due to clogging due to the adhesion of iron or manganese oxidized by ozone gas.

Further, the problem that the U-tube type ozone reaction tank complicates the construction work of the facility as compared with the ordinary diffuser tube type ozone reaction tank system is solved, and the construction cost can be reduced and the reaction It is possible to remove deposits stored in the tank and to easily clean the inside of the tank, and moreover, even if a failure occurs near the bottom of the reaction tank, it is possible to take immediate action.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall ozone treatment system using a U-tube type ozone reaction tank to which the present invention is applied.

FIG. 2 is a graph showing the relationship between the opening of a throttle valve and water pressure in this embodiment.

FIG. 3 is a cross-sectional view of essential parts showing an example of a normal air diffusion tube type ozone reaction tank.

FIG. 4 is a schematic view showing the structure of a normal U-tube type ozone contact tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ozone reaction tank 6 ... Inner pipe 7 ... Ozone generator 8 ... Gas discharge pipe 10 ... Ozone-treated water 11 ... Throttle valve 12 ... Ozone gas injector 13 ... Inner pipe water pressure gauge 14 ... Raw water storage tank 15 ... Raw water inflow pipe 16 … Pressurized booster pump 17… Water pressure gauge 18… Control unit 19… Ozone treated water tank

Claims (2)

[Claims] 1. An U-tube type ozone reaction tank is provided with an inner pipe inside thereof, and ozone gas obtained by an ozone generator and water to be treated are both fed from the upper part of the inner pipe, and the water to be treated and ozone gas are treated together. In a U-tube type ozone reaction tank in which the ozone is continuously contacted as a downward flow in the inner tube to perform a desired ozone treatment, a pressure for increasing the water pressure of the water to be treated is added to the inflow pipe of the water to be treated. In addition to deploying a pump and a water pressure gauge, a throttle valve with adjustable opening and a water pressure gauge are installed near the lower part of the inner pipe, and the water pressure of the treated water measured by the water pressure gauge and the water pressure of the inner pipe are measured. And a control unit for appropriately controlling the opening degree of the throttle valve based on the control signal of the throttle valve so that the water pressure in the inner pipe is within a predetermined range based on the output signal of the control unit. It is characterized in that the opening is adjusted U-tube ozone reaction vessel. 2. The range of the water pressure in the inner pipe is 2.0 to
The U-tube type ozone reaction tank according to claim 1, which has a pressure of 2.5 (kgf / cm ² ).