JPH0866613A - Absorption tower - Google Patents

Abstract

PURPOSE: To reduce the capacity of a liq. tank by arranging a suction port for sucking a liq. absorbent below a side agitating blade in the liq. tank of an absorption tower. CONSTITUTION: In an absorption tower 1 of a flue gas desulfurizer for desulfurizing waste gas from combustion equipment, a liq. absorbent feeding pipe 4 is connected to feed a slurrylike liq. absorbent and a liq. tank 5 is installed in the lower part thereof. The liq. absorbent is sucked from the liq. tank 5 and is sprayed from spray nozzles 7, and also a propellerlike side agitating blade 9 is installed near the side wall to agitate the liq. and air is blown therein. Further, below the agitating blade 9 of the liq. tank 5, a suction port 13 for sucking the liq. absorbent is installed to suck a part of the liq. absorbent in a dead zone D. In this way, the dead zone is effectively used as an oxidizing space to reduce the tank volume.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption tower for desulfurizing a gas to be treated such as exhaust gas from a combustion device and oxidizing a desulfurized absorption liquid.

[0002]

2. Description of the Related Art A wet flue gas desulfurization device is one of the devices for removing sulfur oxides contained in a gas to be treated such as exhaust gas from a combustion device.

This flue gas desulfurization apparatus, as shown in FIG.
In the absorption tower 20, the gas to be treated is brought into contact with a slurry-like absorbing liquid containing an absorbent such as calcium carbonate or magnesium hydroxide to desulfurize the gas to be treated. The absorption liquid is stored in the liquid storage tank 21 in the lower part of the absorption tower 20,
While a part of this is sucked and sprayed into the tower 20 from the spray nozzle 22 provided above the tower 20 and circulated,
The sulfur oxide in the gas is absorbed and removed by the absorbing liquid by making gas-liquid contact with the gas to be processed rising in the tower 20. The absorbing liquid that has absorbed the sulfur oxides falls into the liquid storage tank 21. A side stirring blade 23 for stirring the absorbing liquid is provided in the liquid storage tank 21, and air is jetted to the suction side (back surface side) of the stirring blade 23 so that the air is discharged by the stirring blade 23. Place and disperse in the absorbent. As a result, the absorbing liquid that has absorbed the sulfur oxides is oxidized by the air, and a part of this is extracted to recover gypsum and the like.

[0004]

In the absorption tower 20 described above, air is jetted to the suction side (rear side) of the stirring blade 23, and is put on the discharge flow of the stirring blade 23 so that the air is introduced into the absorbing liquid. A suction port 2 for dispersing, but sucking an absorbing liquid for spraying and circulating the spray from the spray nozzle 22 into the tower 20.
Since 4 is provided at the same level (same height) as the stirring blade 23 (air blowing position), the position of the suction port 24 is set at a constant distance so that a part of the air is not sucked from the suction port 24, The capacity of the liquid storage tank 21 must be increased more than necessary, and the liquid storage tank 21 becomes large.

Therefore, the present invention has been made in view of such circumstances, and an object thereof is to provide an absorption tower capable of downsizing a liquid reservoir tank.

[0006]

In order to achieve the above-mentioned object, the present invention draws an absorption liquid from a lower liquid storage tank,
While spraying and dropping this from the top and circulating it to contact with the gas to be treated to absorb and remove the sulfur oxides in the gas,
In an absorption tower in which air is blown into a liquid storage tank while stirring the liquid absorption by a side stirring blade, a suction port for sucking the absorption liquid is arranged below the side stirring blade of the liquid storage tank. It is a thing.

[0007]

The absorbing liquid in the liquid storage tank is agitated by the discharge flow of the side stirring blades, and when air is blown into the absorption liquid, the air disperses along with the discharge flow. Below is a dead zone where no air is blown. Since the absorbent in the dead zone is sucked through the suction port, almost no air is sucked through the suction port, and the solid content does not accumulate in the dead zone. Further, since the absorbing liquid in which air (oxygen) is dissolved flows into the dead zone, the dead zone can be effectively used as a space for oxidation, and the capacity of the liquid storage tank can be reduced. .

[0008]

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes an absorption tower of a flue gas desulfurization apparatus for desulfurizing exhaust gas (gas to be treated) from a combustion equipment such as a boiler. The absorption tower 1 is formed in a vertical cylindrical shape, for example. An inlet 2 for the gas to be treated is provided on the lower side of the side portion, and an outlet 3 for the gas after desulfurization treatment is provided on the upper portion.

The absorption tower 1 is an absorption liquid for supplying a slurry-like absorption liquid in which an absorption agent such as calcium carbonate or magnesium hydroxide for absorbing sulfur components such as sulfur oxides in the gas to be treated is dissolved. The supply pipe 4 is connected, and a liquid storage tank 5 for storing an absorbing liquid is provided below the inside thereof. Further, a transfer pipe 8 for transferring a part of the absorbing liquid in the tank 5 to a spray nozzle 7 provided above the tower 1 by a circulation pump 6 is connected to the liquid reservoir tank 5,
The absorption liquid sprayed from the spray nozzle 7 and the exhaust gas rising in the tower 1 come into countercurrent gas-liquid contact to absorb and remove the sulfur content in the gas into the absorption liquid, so that the gas to be treated is desulfurized. ing.

Further, a propeller-shaped side surface type stirring blade 9 is rotatably provided near the side wall in the absorbing liquid in the liquid storage tank 5. The stirring blade 9 is attached to a shaft 11 of a motor 10 provided through the side wall of the stirring blade 9,
The shaft of the shaft 11 (stirring blade 9) is disposed obliquely downward and displaced from the center of the tank 5 by a predetermined angle. A discharge flow is generated obliquely downward, whereby a water flow is generated in the circumferential direction and the absorbing liquid in the tank 5 is agitated. The number of the stirrers 14 is arbitrarily determined as long as the absorbing liquid is sufficiently stirred, and when a plurality of stirrers 14 are installed, they are installed at equal intervals in the circumferential direction of the tank.

Furthermore, an air blowing pipe 12 is connected to the liquid storage tank 5, and the air from the air blowing pipe 12 is blown into the absorbing liquid, so that the absorbing liquid which has absorbed the sulfur oxide is air (oxygen). It is supposed to be oxidized by. At this time, the air is dispersed in the absorbing liquid by the discharge flow of the stirring blade 9. The means for blowing air into the absorbing liquid may be any means as long as air is blown into the absorbing liquid and the absorbing liquid that has absorbed the sulfur oxides is sufficiently oxidized, for example,
A liquid such as an absorbing liquid and air may be mixed in advance outside the liquid reservoir tank 5, and the mixed phase flow may be supplied to the tank 5. In addition, the air is discharged from the stirring blade 9 (front side) or suction side (rear side).
Alternatively, it may be dispersed in the absorption liquid by the discharge flow of the stirring blade 9.

Further, below the mounting position of the stirring blade on the side wall of the liquid reservoir tank 5, suction is performed to suck a part of the absorbing liquid in the dead zone D formed below the stirring blade 9 where air is not blown. A port 13 is provided, and the transfer pipe 8 is connected to the suction port 13. The suction port 13 has a dead zone D.
If a part of the absorbed liquid therein is sucked, it may be anywhere below the position where the stirring blade is attached, but preferably near the bottom. The circulation pump 6 that transfers the absorbing liquid to the spray nozzle 7
Since a plurality of pumps are installed and the operating number is determined according to the property of the gas to be treated, the suction ports 13 are also provided according to the number of circulation pumps 6. Therefore, the number of suction ports 13 and the agitator 1
When the number of 4 is the same, the suction port 13 is provided below each stirring blade 9.
If a large number of suction ports 13 are provided, a suction port communicating with a circulating pump that is constantly operated is provided below the stirring blade 9.

Next, the operation of this embodiment will be described.

Exhaust gas (gas to be treated) is introduced into the absorption tower 1 through the inlet 2 and rises in the tower 1. This absorption tower 1
A slurry-like absorbing liquid in which an absorbing agent such as calcium carbonate is dissolved is introduced into the liquid from the absorbing liquid supply pipe 4, and the liquid collecting tank 5
Accumulate inside. A part of it is transferred to the spray nozzle 7 through the transfer pipe 8 by the circulation pump 6, and sprayed and dropped from the nozzle 7 into the tower 1. The absorbing liquid and the gas are countercurrently contacted with each other so that the sulfur content such as sulfur oxides in the gas is absorbed by the absorbing liquid, and the gas to be treated is desulfurized. The desulfurized gas is discharged from the discharge port 3 and guided to another system.

After the desulfurization treatment, the absorbing liquid drops in the tower 1 and collects in the liquid tank 5. This absorption liquid has an air blow pipe 12
Air is blown into the absorbent, and the desulfurized absorption liquid (sulfite) is oxidized. At this time, the stirring blade 9 is rotationally driven by the motor 10. As a result, the liquid on the back surface side (suction side) of the blade 9 is pushed forward of the blade 9 to generate a discharge flow, and a circumferential water flow is generated in the tank 5 to agitate the absorption liquid and also to remove air. It can be dispersed in the absorbent. Further, it is possible to prevent SS from settling in the absorbent.

The absorbed liquid after the desulfurization treatment that has been oxidized is the suction port 1
3 flows into the transfer pipe 8 and a part thereof is guided to another system to collect gypsum and the like.

The suction port 13 is attached to the side wall of the liquid storage tank 5 so as to suck a part of the absorbing liquid in the dead zone D in which the air is not blown, which is formed below the stirring blade 9. Since it is provided below the position, the suction port 13
Almost no air is sucked from. Further, since the absorbing liquid in the dead zone D is sucked, solid content does not accumulate in the dead zone D. Further, by absorbing the absorbing liquid in the dead zone D, the dead zone D
Air (oxygen) is blown (dispersed) into the liquid and the absorbing liquid dissolved in the liquid flows in, so that the dead zone D acts as a space for oxidation. Therefore, it is not necessary to increase the capacity of the liquid storage tank 5, and since the dead zone D below the stirring blade 9 can be effectively used as a space for oxidation, the capacity of the liquid storage tank 5 can be reduced.

[0019]

In summary, according to the present invention, since the suction port is arranged below the lateral stirring blade of the liquid storage tank, the liquid storage tank can be downsized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an example of an absorption tower proposed previously.

[Explanation of symbols]

 1 absorption tower 5 liquid storage tank 9 side stirring blade 13 suction port

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B01D 53/77 B01D 53/34 125 D 125 E

Claims (1)

[Claims] 1. A suction liquid is sucked from a lower liquid storage tank,
While spraying and dropping this from the top and circulating it to contact with the gas to be treated to absorb and remove the sulfur oxides in the gas,
In an absorption tower in which air is blown into a liquid storage tank while stirring the liquid absorption by a side stirring blade, a suction port for sucking the absorption liquid is arranged below the side stirring blade of the liquid storage tank. An absorption tower characterized by that.