JPS6132046B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a countercurrent type gas-liquid contact device that performs absorption and reaction between a gas and a liquid.

In order to cause the liquid to absorb gas components and react with the liquid, the liquid to be treated is introduced from the top of the container, and the gas is fed into the liquid from the bottom of the container to create a downward flow. A countercurrent type gas-liquid contact tower is used to treat the liquid to be treated by bringing the liquid to be treated into contact with the gas flowing upward.

The top of the contact column is The gas is sealed, and an exhaust pipe is installed to guide the gas to an exhaust gas treatment device for exhaust gas treatment, or to utilize the active ingredients remaining in the exhaust gas, it is further guided to another gas-liquid contact device for absorption to improve absorption efficiency. At the same time, the gas is detoxified and released.

For example, when ozone is injected into the conventional secondary treatment at a human waste treatment plant to perform decolorization and advanced treatment of wastewater, the ozone injected from the bottom of the ozone reaction tower through a diffuser pipe is transferred to the top of the tower. It is absorbed by gas-liquid contact into the secondary treated water introduced from the water, and its strong oxidizing power oxidizes and decomposes colored components and organic substances in the treated water, decolorizing it and reducing COD (chemical oxygen demand). Since ozone is extremely harmful to humans and plants, the top of the ozone reaction tower must be sealed.
The exhaust gas is led to an ozone decomposition tower and decomposed through an activated carbon layer before being released, or if the ozone concentration in the exhaust gas is still high, the exhaust gas is recycled. In the case of human waste treated water, the foaming components in the treated water cause intense foaming in the ozone reaction tower, but since this foam is discharged together with the exhaust gas, it is recommended to install a defoaming tower in front of the ozone decomposition tower to separate the foam. It's normal.

To explain the above in more detail using Fig. 1, in Fig. 1 1 is an ozone reaction tower, and the water to be treated enters the reaction tower through an inlet pipe 2 and flows downward, and from the bottom of the tower it passes through a pipe 3 to an aeration pipe. Gas-liquid contact is carried out in a countercurrent flow with the ozone injected through 4, and the liquid rises in a liquid outlet pipe 5, enters a treated water tank 8 through a pipe 7, and is discharged from an outlet 9. On the other hand, ozone exits into the space 10 above the liquid surface and passes through the exhaust pipe 11 along with the generated bubbles to the defoaming tower 1.
2, the bubbles are removed by a shower from the spray pipe 13, the mist is removed by the mist separator 17, and while passing through the activated carbon layer in the ozone decomposition tower 16 through the pipe 15, it is decomposed and released into the atmosphere. Ru.

In such conventional methods, there is frictional resistance of the fluid in the flue gas exhaust pipe and pressure loss in the ozone decomposition tower.Furthermore, when the residual ozone concentration in the flue gas is high, the flue gas is transferred to the front stage of the reaction tower 1. Although the water to be treated is brought into gas-liquid contact in another reaction tower (not shown), there is a pressure loss due to this water head. If the exhaust gas flows with bubbles through the exhaust pipe, the resistance increases further.

As described above, the gas pressure loss caused by the channels and devices provided for after-treatment of the exhaust gas directly becomes back pressure and brings a pressure higher than atmospheric pressure to the gas-liquid contact column top space 10.

The liquid level in the reaction tower is determined by the length of the liquid outlet pipe 5, and the top of the pipe 5 is connected to a siphon breaker 6.
Since the pressure is at atmospheric pressure, if back pressure is applied to the column interior space 10, the liquid level will drop by an amount corresponding to the differential pressure from atmospheric pressure expressed in a liquid column. Since the back pressure is not always constant and constantly fluctuates depending on the amount of gas injected, the degree of foaming, and the conditions of after-treatment of the exhaust gas, the liquid level in the column also fluctuates accordingly.

If the liquid level fluctuates, the residence time of the liquid in the reaction tower changes, and the absorption efficiency of the gas also changes, making it impossible to obtain a stable treatment effect. Figure 2 shows an example of the relationship between the absorption efficiency of ozone into water and the liquid depth.

As is clear from the above explanation, in the conventional countercurrent type gas-liquid contact tower, fluctuations in the liquid level were unavoidable, resulting in fluctuations in the quality of the treated water. In particular, during ozonation of treated human waste water, foaming is intense, and there are cases where the total resistance of the exhaust pipe after the reaction tower and the mist separator of the defoaming tower exceeds 1000m/m of water column. The liquid level dropped by more than 1 meter due to back pressure, which became a problem.

The present invention provides a countercurrent type gas-liquid contact device that has efficient and stable performance by eliminating fluctuations in the liquid level due to changes in the resistance of the exhaust gas pipe in such a gas-liquid contacting device and always maintaining a constant water depth. A contact device is provided.

The present invention will be explained below with reference to the drawings.

FIG. 3 is a system diagram showing one embodiment of the present invention. In Fig. 3, reference numeral 1 denotes a gas-liquid contact tower, in which the liquid to be treated enters through an inlet pipe 2, makes countercurrent contact with a gas such as ozone injected from a diffuser pipe 4, rises through a liquid outlet pipe 5, and reaches the top of the tower. Liquid sealing U-shaped tube 1 which becomes the liquid sealing part
8 and enters the treated water tank 8 through a pipe 7 fitted with a siphon breaker 6, and is discharged from the discharge port.

On the other hand, the gas body temporarily accumulates in the space 10 above the liquid level and passes through the exhaust pipe 11 to the defoaming tower 12 and the ozone decomposition tower 16.
The method is the same as the conventional method, but since the column internal space 10 and the small space 20 provided at the top of the liquid outlet pipe 5 are connected by a pressure pipe 19, the column internal space is The pressures applied to 10 and small space 20 become equal. The liquid sealing U-shaped pipe 18 has a sufficiently large pipe diameter for the amount of water to be treated, and the overflow port 21 to the liquid guide pipe 7 is provided at a position equal to or lower than the liquid level in the column, and the U-shaped pipe 18 is The length of the pipe between the lowest part of the pipe and the overflow port 21 is:
The gas pipe line after the exhaust pipe 11 is manufactured to be longer than the maximum value of the total flow resistance expressed by the liquid column of the processing liquid.

In this way, the small space 20 at the top of the liquid conduit 5 and the inner space 10 of the column are isolated from the atmosphere by the U-shaped pipe 18 for liquid sealing.
Since the pressure is the same in the impulse pipe 19, the liquid level in the column is
Regardless of the magnitude of the back pressure, it is equal to the height of the liquid conduit 5 and can be kept constant.

In FIG. 3, the structure of the liquid seal part is U-shaped, but any structure may be used as long as it has a similar liquid seal effect. For example, if there is a treated water tank nearby, the liquid seal pipe 21 is placed under the liquid level of the treated water tank as shown in Figure 4.
Just insert it a little longer than the required liquid column.

As explained above, according to the present invention, fluctuations in the liquid level in the column due to changes in the resistance of the exhaust gas pipe in a countercurrent gas-liquid contact column are eliminated, and a constant water depth is always maintained, thereby improving efficiency. Thus, an improved countercurrent gas-liquid contacting device with a reliable and stable gas-liquid contacting effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an example of a conventional countercurrent gas-liquid contact device, Fig. 2 is a diagram showing an example of the relationship between ozone absorption efficiency into water and water depth, and Fig. 3 is a countercurrent type of the present invention. FIG. 4 is a system diagram showing one embodiment of the gas-liquid contact device, and FIG. 4 is a system diagram showing another embodiment of the present invention. 1: Gas-liquid contact tower, 2: Treated liquid introduction pipe, 3: Gas introduction pipe, 4: Diffusion pipe, 5: Treated liquid outlet pipe, 6:
Siphon breaker, 7: Liquid guide pipe, 8: Treatment water tank,
9: Discharge port, 10: Space (gas reservoir), 11: Exhaust pipe, 12: Defoaming tower, 13: Spray pipe, 14:
Antifoaming liquid outlet, 15: Exhaust pipe, 16: Ozone decomposition tower (activated carbon tower), 17: Mist separator, 1
8, 21: Liquid sealing tube, 19: Impulse tube, 20: Space (equal pressure space), 21: Overflow port.

Claims (1)

[Scope of Claims] 1. Gas-liquid contact in which the liquid to be treated is introduced from the top and the gas for treatment is fed into the liquid from the bottom to bring the gas body into contact with the liquid to be treated to treat the liquid to be treated. A tower, a riser branching from near the bottom of the gas-liquid contact tower, and a space provided above the riser pipe and sealed from the outside at a position higher than the level of the liquid to be treated in the gas-liquid contact tower. , a pressure impulse pipe that communicates this sealed space with an air pocket above the level of the liquid to be treated in the tower, and a pressure pipe that is located below the sealed space and is located between the sealed space and the outlet to the outside. A countercurrent gas-liquid contact device, comprising: a liquid seal portion having a liquid column length capable of absorbing a pressure increase occurring in a space.