JPH08103648A - Packed tower type gas-liquid contact device - Google Patents

Abstract

PURPOSE: To provide a packed tower type gas-liquid contact device short in rising time at the time of restarting operation and small in futile use of a liquid to be treated and a gas. CONSTITUTION: In the packed tower type gas-liquid contact device having plural stages of a supporting plate 2 fitted with a down comer 3 in the upper and lower direction in a treating tower 1, provided with a packed bed 5 on each supporting plate and for passing the liquid to be treated in the downward direction and the gas in the upward direction to allow the liquid to be treated to countercurrently contact with the gas in the packed bed of each stage, a small hole 12 is provided on the supporting plate 2 in order to prevent the remaining of liquid to be treated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a degassing tower for releasing and dissolving dissolved oxygen in water with a degassing gas such as nitrogen gas when producing pure water or ultrapure water, and a degassing tower The present invention relates to a packed-column gas-liquid contactor that can be used in an absorption tower that absorbs and removes ammonia in water.

[0002]

2. Description of the Related Art A degassing tower shown in FIG. 3 will be explained as an example. A support plate 2 having a downcomer 3 and a gas riser 4 mounted therein is fixed in a vertical direction in a plurality of stages in a processing tower 1, and each support plate is mounted on each support plate. The Raschig ring filling layer 5 is provided, and the liquid to be treated is sprinkled on the uppermost filling layer by the water supply pipe 6 and the water sprinkling device 7 so that the liquid to be treated flows downward through the downcomers of the supporting plates at each stage. A degassing gas such as nitrogen gas is supplied to the lower side of the supporting plate of the lower packed bed through an air supply pipe 8, and the degassing gas is caused to flow upward through a gas riser of the supporting plate of each stage, so that the degassing gas in each packed bed A degassing tower is conventionally known in which the solution to be treated and the degassing gas are countercurrently contacted with each other to dissipate and remove the dissolved oxygen in the solution to be treated by the degassing gas. It is discharged from the top exhaust port 9 and the degassed water is collected in a water tank 10 at the bottom of the tower,
Water is supplied by the pump P and the water supply pipe 11.

During the deaeration operation, the liquid to be treated is allowed to flow down uniformly from the packed layer in the upper stage to the packed layer in the lower stage, and in order to prevent the liquid to be treated from flowing unevenly in the packed layer, as shown in FIG. As shown, the liquid inlet 3'of the downcomer having an oblique opening at the upper end attached to the support plate of each stage is located above a certain height from the upper surface of the support plate. Therefore, when the liquid to be treated accumulates on the support plate and the water level h tries to rise above the position of the liquid inlet at the upper end of the downcomer, the accumulated liquid to be treated overflows into the liquid inlets of all downcomers. Then, it flows all at once into the lower packed bed.

[0004]

Since the position of the liquid inlet 3'of the downcomer is set higher than the upper surface of the support plate as described above, when the operation is stopped, the liquid inlet 3'is provided on each of the support plates. The liquid to be treated below the 3'position remains,
The water quality of the remaining liquid to be treated is deteriorated by the atmosphere in the tower. In particular, when used for the production of ultrapure water, this deterioration of water quality becomes a serious problem at the order of ppb, which is the required water quality level of ultrapure water. Therefore, when the operation is restarted, the residual liquid to be treated is degassed and flows down to the water tank 10 at the lower part of the tower. Therefore, this is discarded and the liquid to be treated supplied after restarting the operation becomes treated water and is stored in the water tank. Since it is necessary to wait for the treated water to be fed until it is accumulated, it takes a long time (usually about 90 minutes) to rise after the operation is restarted, and the operation efficiency is reduced. Further, during that time, the liquid to be treated and the gas for deaeration have to be supplied, which is wasted and causes a loss.

[0005]

In order to solve the above problems, the present invention is characterized in that small holes are formed in the support plates of each stage to prevent the residual liquid to be treated from remaining.

[0006]

1 and 2 show a supporting plate of each stage according to the present invention, in which a downcomer 3 and a gas riser 4 are attached and a small hole 12 is formed at one place or a plurality of places for preventing residual liquid to be treated. I am doing it. The diameter of the small holes 12 is about 5 to 10 mm, and the opening ratio of the small holes is 10% or less of the total opening area of the downcomer.
It is preferably 0.1 to 5%. The positions of the small holes of the upper support plate and the small holes of the lower process are confused so that the liquid to be treated flowing down from the small holes of the support plate of the upper process during deaeration is Pass through the packed bed, flow down from the small holes in the lower support plate,
Avoid short circuit flow that results in insufficient degassing.

When the small holes 12 are formed in the support plates of the respective stages in this way, when the degassing operation is stopped, the liquid to be treated accumulated on the support plates of the respective stages passes through the small holes to fill the lower stage. Drained into layers,
Eventually, it fell into the water tank 10 through the small holes in the bottom support plate,
Depending on the length of the interruption time of the operation, for example, when degassing operation is performed for 24 hours, operation is stopped for 24 hours, and then operation is restarted, the liquid to be treated in the previous operation is on the support plate of each stage. Almost never.

Therefore, when the operation is restarted, the previous liquid to be treated accumulated in the water tank 10 is discharged and discarded, and it takes about 20 minutes to completely fill the inside of the degassing tower with the degassing gas. Degassed water can be obtained with a rise time of about a certain degree.

The downcomer and the gas riser are not limited to those having the illustrated structure. Further, the processing tower is not limited to the degassing tower, and may be an absorption tower.

[0010]

As is apparent from the above, according to the present invention, there can be obtained a packed column gas-liquid contactor in which the rise time after resumption of operation is significantly shortened. Therefore, the operating efficiency is increased, and the amount of liquid or gas to be treated that is wasted is small. Furthermore,
Since it is only necessary to form a small hole in the support plate, the existing tower can be easily modified and implemented.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a part of a main part of a degassing tower of the present invention.

2 is a plan view of a half of FIG. 1. FIG.

FIG. 3 is a sectional view of the entire degassing tower.

FIG. 4 is an enlarged sectional view of a part of a support plate of a conventional degassing tower.

5 is a plan view of a half of FIG. 4. FIG.

[Explanation of symbols]

 1 treatment tower 2 support plate 3 downcomer 3'downcomer liquid inlet 4 gas riser 5 packed bed 6 water supply pipe 7 water sprinkler 8 air supply pipe 9 exhaust pipe 10 water tank 11 water supply pipe 12 small holes

Claims (1)

[Claims] 1. A support plate having downcomers attached thereto is vertically fixed in a plurality of stages in a treatment tower, a packed bed is provided on each support plate, and a liquid to be treated is allowed to flow downward in the tower, and a gas is supplied. In the packed column gas-liquid contactor that causes the liquid to be treated and the gas to flow countercurrently in the packed beds of each stage, a small hole for preventing residual liquid to be treated has been opened in the support plate. Characteristic packed tower gas-liquid contactor.