JP2002239339A - Wet type flue gas desulfurization apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet type flue gas desulfurization apparatus in which appliances for oxidizing and stirring an absorption solution are installed in the outside of an absorption tower so that the appliances can be repaired and replaced without requiring the absorption solution in a liquid storage part to be discharged and while the effect on the operation in the entire power generation facilities being suppressed to the minimum. SOLUTION: A circulation pipeline 14 equipped with a pump 13 for sucking an absorption solution in a liquid storage part and circulating the solution is connected to the outside of an absorption tower 14 through shut-off valves 15, 16 and an air supply pipe 6 for blowing oxidizing air is connected to the discharge side of the pump 13 of the circulation pipeline 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet flue gas desulfurization apparatus.

[0002]

2. Description of the Related Art Generally, since flue gas discharged from a coal-fired boiler or the like of a power generation facility contains sulfur oxides (SO ₂ ), wet flue gas is discharged downstream of the coal-fired boiler or the like. 2. Description of the Related Art A desulfurization device is installed, and in the wet flue gas desulfurization device, exhaust gas and an absorbing solution are brought into gas-liquid contact to remove sulfur oxides contained in the exhaust gas.

FIG. 3 and FIG. 4 show an example of a conventional wet flue gas desulfurization apparatus, which generally uses calcium carbonate (CaCO ₃ ) as an absorbent. An absorption tower 4 in which a liquid reservoir 2 for absorbing liquid 1 is formed at a lower part and a number of spray nozzles 3 are arranged at an upper part.
And a circulating pump 5 for pumping up the absorbent 1 in the liquid reservoir 2 of the absorption tower 4 and spraying it from the spray nozzle 3 for circulation.
Oxidized air is supplied to the liquid reservoir 2 of the absorption tower 4 by an air supply pipe 6
, An oxidizing air blower 7 supplied through a rotary shaft 9, and a stirrer 11 for rotating an agitating blade 10 by an electric motor 8 via a rotating shaft 9 to stir the absorbing liquid 1 in the liquid reservoir 2, and to collect mist in the exhaust gas. The mist eliminator 12 is provided.

In the case of the above-mentioned wet flue gas desulfurization apparatus, exhaust gas discharged from a coal-fired boiler (not shown) is introduced into an absorption tower 4 of the wet flue gas desulfurization apparatus. 1 is circulated while being sprayed from a large number of spray nozzles 3 by the operation of the circulation pump 5, and the sulfur oxides contained in the exhaust gas are removed by the gas-liquid contact between the exhaust gas and the absorbing liquid 1. The exhaust gas from which the matter has been removed is guided downstream after the mist is collected by the mist eliminator 12.

On the other hand, the absorbent 1 having absorbed the sulfur oxides from the exhaust gas is dropped into the liquid reservoir 2, where the air supply pipe 6 is operated by the operation of the oxidizing air blower 7.
Impeller 1 of the stirrer 11 while oxidizing air is blown from the
The absorption liquid 1 is stirred by the rotation of 0, whereby the absorption liquid 1 is forcibly oxidized to produce gypsum (calcium sulfate (CaSO ₄ )), and the liquid storage section 2 containing the gypsum The absorption liquid 1 in the inside is drawn out from the bottom of the absorption tower 4 to a gypsum recovery system by operating a bleed pump (not shown).

In the wet flue gas desulfurization apparatus shown in FIGS. 3 and 4, the air supply pipe 6 is formed by branching a branch pipe 6c having a large number of nozzle holes 6b from a main pipe 6a. A so-called pipe sparger system in which oxidizing air is blown into the entire liquid reservoir 2 is employed. In addition to the above, for example, as shown in FIGS. 6d is opened near the front of the stirring blade 10 of the stirrer 11, and the stirrer 1
There is also a wet flue gas desulfurization apparatus adopting a so-called side atomizing method in which oxidizing air is blown into the vicinity of the front of one stirring blade 10.

[0007]

However, in the case of the wet flue gas desulfurization apparatus employing the pipe sparger system as shown in FIGS. 3 and 4, there are a large number of branch pipes 6c branching from the main pipe 6a. In addition, the flow rate of the oxidizing air in each branch pipe 6c tends to be unbalanced, and each branch pipe 6c is thin and the diameter of the nozzle hole 6b is small. Since the blades 10 are installed in the liquid reservoir 2 of the absorption tower 4, the stirrer 1
In order to perform repair, replacement, or the like of the fuel cell 1, it was necessary to drain the absorbent 1 from the liquid reservoir 2, and the operation of the entire power generation facility had to be stopped.

Further, in the case of a wet flue gas desulfurization apparatus employing a side atomizing method as shown in FIGS. 5 and 6,
Although there is no risk of imbalance in the flow rate of oxidizing air in the air supply pipe 6 or blockage of the tip outlet 6d of the air supply pipe 6, the stirring blade 10 of the stirrer 11 is Since it is installed in the liquid reservoir 2 of the absorption tower 4, it is necessary to drain the absorbent 1 in the liquid reservoir 2 in order to repair or replace the stirrer 11. Had to stop.

In the present invention, in view of such circumstances, a device for oxidizing and stirring the absorbing solution can be installed outside the absorption tower, and the device can be repaired or replaced by draining the absorbing solution in the liquid reservoir. It is an object of the present invention to provide a wet-type flue gas desulfurization apparatus which can be carried out without any effect and can minimize the influence on the operation of the entire power generation equipment.

[0010]

SUMMARY OF THE INVENTION According to the present invention, an absorbent is pumped up from a liquid reservoir at the bottom and sprayed from above, and the absorbent is brought into contact with the exhaust gas to absorb sulfur oxides while absorbing the sulfur oxides. A wet-type flue gas desulfurization device comprising an absorption tower configured to blow oxidizing air into the absorption liquid in the liquid reservoir to oxidize the liquid, wherein the absorption liquid in the liquid reservoir is sucked into the outside of the absorption tower. A wet flue gas desulfurization apparatus characterized in that a circulation pipe provided with a pump for circulation is connected via a shut-off valve, and an air supply pipe for blowing oxidizing air is connected to the pump discharge side of the circulation pipe. Things.

According to the above means, the following effects can be obtained.

Exhaust gas discharged from a coal-fired boiler or the like is introduced into an absorption tower of a wet-type flue gas desulfurization unit. By the gas-liquid contact between the exhaust gas and the absorbent, sulfur oxides contained in the exhaust gas are removed, while the absorbent absorbing the sulfur oxides from the exhaust gas is dropped into a liquid reservoir, In the liquid reservoir, the oxidizing air is blown from the air supply pipe to the pump discharge side of the circulation pipe while the shut-off valve is opened, and the absorption liquid in the liquid reservoir is sucked into the circulation pipe by the operation of the pump. The liquid is discharged to the liquid reservoir and circulated, and the absorbing liquid in the liquid reservoir is stirred, whereby the absorbing liquid is forcibly oxidized.

When the pump as a device for oxidizing and stirring the absorbing liquid is repaired or replaced, the shut-off valve is closed so that the pump can be pumped without draining the absorbing liquid from the liquid reservoir. Since it is possible to separate the circulation pipe provided with the gas from the absorption tower, it is not necessary to stop the operation of the entire power generation equipment.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an example of an embodiment of the present invention. In the drawings, the portions denoted by the same reference numerals as those in FIGS. 3 to 6
However, the present embodiment is characterized in that, as shown in FIGS. 1 and 2, the absorption liquid 1 in the liquid reservoir 2 is sucked and circulated outside the absorption tower 4. The point is that the circulation pipe 14 provided with the pump 13 is connected via the shut-off valves 15 and 16, and the air supply pipe 6 for blowing oxidized air is connected to the discharge side of the pump 13 of the circulation pipe 14.

The pump 13 is not limited to an ordinary pump, but may be a jet pump or the like.

Next, the operation of the above illustrated example will be described.

As in the conventional case, the exhaust gas discharged from a coal-fired boiler (not shown) is supplied to an absorption tower 4 of a wet flue gas desulfurization apparatus.
In the absorption tower 4, the absorbing liquid 1 is circulated while being sprayed from a number of spray nozzles 3 by the operation of the circulation pump 5. The sulfur oxides contained in are removed,
The exhaust gas from which the sulfur oxides have been removed is guided downstream after the mist is collected by the mist eliminator 12.

On the other hand, the absorbent 1 having absorbed the sulfur oxides from the exhaust gas is dropped into the liquid reservoir 2 where the shut-off valves 15 and 16 are opened and the oxidized air is absorbed. The oxidizing air is blown from the air supply pipe 6 to the discharge side of the pump 13 of the circulation pipe 14 by the operation of the blower 7, and the absorption liquid 1 in the liquid reservoir 2 is discharged by the operation of the pump 13.
4, the liquid 1 is discharged to the liquid reservoir 2 and circulated, and the liquid 1 in the liquid reservoir 2 is stirred, whereby the liquid 1 is forcibly oxidized and gypsum (calcium sulfate ( CaSO ₄ )) is generated, and the absorbent 1 in the reservoir 2 containing the gypsum is drawn out from the bottom of the absorption tower 4 to a gypsum recovery system by operating a bleed pump (not shown).

Here, when repairing or replacing the pump 13 as a device for oxidizing and stirring the absorbing liquid 1,
By closing the shutoff valves 15 and 16, the circulation pipe 14 provided with the pump 13 can be separated from the absorption tower 4 without having to draw out the absorbent 1 in the liquid reservoir 2,
It is not necessary to stop the operation of the entire power generation facility.

It is needless to say that there is no fear of imbalance in the flow rate of oxidizing air in the air supply pipe 6 or blockage of the air supply pipe 6.

In this way, a device for oxidizing and stirring the absorbing solution 1 can be installed outside the absorption tower 4, and the device can be repaired or replaced without removing the absorbing solution 1 in the liquid reservoir 2. And the effect on the operation of the entire power generation facility can be minimized.

The wet-type flue gas desulfurization apparatus of the present invention is not limited to the above-described example, but may be variously modified without departing from the gist of the present invention.

[0024]

As described above, according to the wet flue gas desulfurization apparatus of the present invention, a device for oxidizing and stirring the absorbing solution can be installed outside the absorption tower, and the device can be repaired or replaced. To
This can be performed without draining the absorbing liquid in the liquid reservoir, and an excellent effect of minimizing the influence on the operation of the entire power generation equipment can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a view corresponding to the direction of arrows II-II in FIG.

FIG. 3 is a schematic configuration diagram of a conventional example.

FIG. 4 is a view corresponding to the view taken along the line IV-IV in FIG. 3;

FIG. 5 is a schematic configuration diagram of another conventional example.

FIG. 6 is a view corresponding to the view along the line VI-VI in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Absorbent liquid 2 Liquid storage part 4 Absorption tower 6 Air supply pipe 7 Oxidation air blower 13 Pump 14 Circulation piping 15 Shutoff valve 16 Shutoff valve

Claims (1)

[Claims] 1. An absorbent is pumped up from a liquid reservoir at the bottom and sprayed from above, and the absorbent is brought into contact with exhaust gas to absorb sulfur oxides and returned to the liquid reservoir. A wet flue gas desulfurization device comprising an absorption tower for oxidizing air by blowing oxidizing air into the liquid, wherein a circulation pump is provided outside the absorption tower for sucking and circulating the absorption liquid in a liquid reservoir. A wet flue gas desulfurization device, wherein a pipe is connected via a shutoff valve, and an air supply pipe for blowing oxidizing air is connected to a pump discharge side of the circulation pipe.