JPH08252426A - Absorption tower - Google Patents

Abstract

PURPOSE: To prevent a solid from accumulating in a liquid storage tank. CONSTITUTION: This absorption tower sucks a part of an absorption liquid in a lower part liquid storage tank 5 through plural suction apertures 10 while stirring the absorption liquid using a stirrer 6 provided on a wall surface, then drops the atomized absorption liquid from top, and causes the liquid to come into contact with a gas to be treated while, circulating the liquid to absorb and remove sulfur oxides contained in the gas. In this absorption tower, at least one of the plural suction apertures 10 is arranged so that the absorption liquid in the center of the liquid storage tank 5 is sucked.

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 processed such as exhaust gas from a combustion device, and more particularly to an absorption tower for preventing solids from being accumulated in a liquid tank.

[0002]

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

In this flue gas desulfurization apparatus, as shown in FIGS. 3 and 4, the gas to be treated is brought into contact with a slurry-like absorbent containing a calcium-based absorbent such as calcium carbonate in the absorption tower 1. The gas to be treated is desulfurized. The absorption liquid is stored in the liquid storage tank 5 in the lower part of the absorption tower 1, and a part of the absorption liquid is sucked from a plurality of suction ports 11 and sprayed into the tower 1 from a spray nozzle 8 provided above the inside of the tower 1. While being circulated, the sulfur oxide in the gas is absorbed and removed by the absorption liquid by making a gas-liquid contact with the gas to be processed rising in the tower 1. The absorbing liquid that has absorbed the sulfur oxides falls into the liquid storage tank 5, and this liquid is stirred by the side stirring blades 6. A part of the circulating absorption liquid is extracted and oxidized, and then recovered as gypsum.

[0004]

By the way, in the above-mentioned absorption tower, as shown in FIGS. 3 and 4, a side stirrer 6 is arranged on the peripheral wall of the liquid storage tank 5 (absorption tower) to provide a tank. The inside of the tank 5 (tower) has a diameter of about 15 to 20 m, and the stirring effect by the stirrer 6 is weak in the central portion of the tank 5, that is, a side stirrer. With 6 alone, the center of the tank stagnates. As a result, solid matter is mainly deposited in the central portion of the tank 5, and gypsum is mainly accumulated and accumulated to form a solid matter 12 having a diameter of 3 to 4 m and a height of 2 m, for example. The deposit 12 is removed at the time of maintenance, but it is very hard and requires considerable labor such as crushing to remove it.

Therefore, the present invention has been made in view of such circumstances, and an object thereof is to provide an absorption tower capable of preventing the accumulation of solid matter.

[0006]

In the absorption tower of the present invention, while agitating the absorbing liquid in the lower liquid storage tank with a stirrer on the wall surface, a part of it is sucked from a plurality of suction ports and sprayed from the upper part. In an absorption tower that absorbs and removes sulfur oxides in the gas by bringing it into contact with the gas to be treated while circulating it, at least one of the suction ports is adapted to suck the absorption liquid in the central portion of the liquid storage tank. It is arranged.

[0007]

The absorbing liquid in the liquid storage tank is agitated by the water flow by the agitator on the wall surface, but the agitating effect is weak in the central portion of the tank. Therefore, by arranging at least one of the suction ports so that the absorption liquid in the central portion in the liquid storage tank is sucked, the absorption liquid is sucked from the central portion, so that stagnation does not occur in the central portion. . Therefore, it becomes possible to prevent the accumulation of solid matter in the liquid storage tank.

[0008]

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

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

The absorption tower 1 is supplied with a slurry-like absorption liquid in which a calcium-based absorbent such as calcium carbonate for absorbing sulfur components such as sulfur oxides in the gas to be treated is dissolved. The pipe 4 is connected, and a liquid storage tank 5 for storing the absorbing liquid is provided below the inside thereof. The peripheral wall of the liquid storage tank 5 (tower 1) has a plurality of 4 in the illustrated example.
One stirrer 6 is provided, and the stirrer 6 causes a water flow in the circumferential direction to stir the absorbing liquid in the tank 5.

A circulation pipe 9 is connected to the liquid storage tank 5 to transfer a part of the absorption liquid in the tank 5 to a spray nozzle 8 provided in the upper part of the tower 1 by a circulation pump 7. The absorbing liquid sprayed from the nozzle 8 and the exhaust gas rising in the tower 1 come into countercurrent gas-liquid contact, the sulfur content in the gas is absorbed and removed by the absorbing liquid, and the gas to be treated is desulfurized. There is. A plurality of circulation pipes 9 (including the circulation pump 7) for transferring the absorbing liquid to the spray nozzles 8 (for example, 8 to
18) Installed, and the number of operating machines can be arbitrarily determined according to the load (property of the gas to be treated, etc.). The circulation pipe 9 is connected to the peripheral wall of the liquid storage tank 5, and the suction port 10
At least one (one or more) of them is arranged in the central portion near the inner bottom portion of the tank 5 or in the vicinity of the central portion (central portion in the example shown in FIG. 1), and the absorption liquid in the central portion of the inner bottom portion of the tank 5 is sucked. It is like this. That is, an arbitrary (one or more) circulation pipe 9 is extended to the central part in the vicinity of the bottom of the tank 5 or to the vicinity of the central part. Thus, the extending circulation pipe 9 includes a pipe that is constantly operated (sucked).
Note that FIG. 1 is a diagram showing a state in which four circulation pipes 9 are connected to a liquid storage tank 5 (absorption tower 1) for easy understanding.

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
For example, a slurry-like absorption liquid in which an absorption agent of calcium carbonate is dissolved is introduced from the absorption liquid supply pipe 4 and accumulated in the liquid storage tank 5. A part thereof is transferred to the spray nozzle 8 via the circulation pipe 9 by the circulation pump 7, and the nozzle 8
Spray down 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 falls in the tower 1 and collects in the liquid storage tank 5. A part of the absorbing liquid is appropriately extracted and oxidized, and then recovered as gypsum. The absorbing liquid in the tank 5 is agitated by the water flow in the circumferential direction by the agitator 6, and there is no problem in a place where the water flow is strong, but when the water flow is weak, solid content is accumulated. The place where the water flow is weak, that is, the place where the stirring effect is weak is the center of the tank 5, and the suction port 10 of the circulation pipe 9 is arranged near the bottom of the center. As a result, the liquid in the central portion is sucked from the suction port 10, so that stagnation does not occur in the central portion even if the stirring effect is weak. Therefore, it is possible to prevent the accumulation of solid matter in the liquid storage tank 5. This will remove the deposits,
Maintenance such as regular inspections becomes easy.

[0015]

In summary, according to the present invention, the excellent effect of preventing the accumulation of solid matter in the liquid storage tank can be obtained.

[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.

FIG. 3 is a diagram showing an example of a state in which solid matter is accumulated in the center of the bottom of the absorption tower.

FIG. 4 is a view taken along the line AA of FIG.

[Explanation of symbols]

 1 Absorption tower 5 Liquid storage tank 6 Stirrer 10 Suction port

Claims (1)

[Claims] 1. While stirring the absorbing liquid in the lower liquid storage tank by means of a stirrer on the wall surface, a part of the liquid is sucked from a plurality of suction ports, sprayed and dropped from the upper part, and circulated so as to come into contact with the gas to be treated. In an absorption tower that absorbs and removes sulfur oxides in gas, at least one of the suction ports is arranged so that the absorption liquid in the central portion of the liquid storage tank is sucked.