JP2002253925A - Wet type stack gas desulfurization apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a wet type stack gas desulfurizing apparatus with a low operation cost by suppressing sucking bubbles into a circulation pump to prevent the deterioration of desulfurization performance without increasing equipment cost sharply. SOLUTION: A baffle plate 15 having a upper end projected up to the liquid level and provided with an absorbing liquid circulation opening part between the lower end part and the bottom surface of a circulation tank 6 is mounted at the vicinity of a suction pipe line 14 of the absorbing liquid circulation pump 4 provided on the wall surface of the circulation tank 6 to divide the tank into 2 zones and air is blown into an absorbing liquid 5 in an oxidation zone side in the divided two zones in the circulation tank 6, where the suction pipe line 14 is not present, through an air blow pipe line 8, liquid drops falling down into the absorbing liquid 5 in the non-oxidation zone in the circulation tank 6, where the suction pipe line 14 is present, are recovered in a upper part space in the non-oxidation zone and all of the recovered absorbing liquid 5 is fed to the oxidation zone side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the combustion of a boiler or the like.
Sulfur dioxide (SO ₂)
Related to wet flue gas desulfurization equipment to remove, especially circulation tank
Optimize the structure of the air bubble prevention plate provided in the section
This reduces air bubbles in the circulation pump,
Function to prevent gas drift at the outlet duct of the desulfurization unit
The present invention relates to a wet-type flue gas desulfurization apparatus provided with the above.

[0002]

2. Description of the Related Art In thermal power plants and the like, sulfur oxides in flue gas generated by combustion of fossil fuels, especially SO
No. ₂ is one of the main causes of environmental problems such as air pollution and acid rain. In recent years, the spread of flue gas desulfurization systems on a global scale has been desired.

[0003] The current flue gas desulfurization system is dominated by the wet method based on the limestone-gypsum method, and the spray method, which has the highest track record and is highly reliable, is widely used worldwide. This spray-type wet flue gas desulfurization system has high desulfurization performance, and the basic technology is almost established.

However, with the diversification of fuels and the reduction of wastewater, strict operating conditions are required for the wet flue gas desulfurization system, and in order to maintain desulfurization performance and prevent troubles from occurring. There is a need for more advanced technology development.

FIG. 4 shows a side view of an absorption tower which constitutes a desulfurization apparatus as a known example of a conventional wet flue gas desulfurization apparatus employing a spray method. The wet flue gas desulfurization apparatus mainly includes an absorption tower main body 1, an inlet duct 2, an outlet duct 3, an absorbent circulation pump 4, a circulation tank 6, a stirrer 7, an air blowing pipe 8,
It is composed of a mist eliminator 9, an absorbing liquid discharge pipe 10, a circulation pipe 11, a spray header 12, a spray nozzle 13, a suction pipe 14, and the like. A plurality of spray nozzles 13 are provided in a cross section orthogonal to the gas flow,
Further, a plurality of stages are provided in the gas flow direction. Further, the stirrer 7 and the air blowing pipe 8 are installed in the circulation tank 6 in which the absorbing liquid 5 stays, and the mist eliminator 9 is installed in the outlet duct 3.

Exhaust gas discharged from a boiler (not shown) is introduced into an absorption tower main body 1 from an inlet duct 2 in a substantially horizontal direction by a desulfurization fan (not shown), and discharged from an outlet duct 3 provided at the top of the tower. You. During this time, the absorbing liquid 5 containing calcium carbonate sent from the absorbing liquid circulating pump 4 is jetted from the spray nozzle 13, and gas-liquid contact between the absorbing liquid 5 and the exhaust gas is performed. At this time, the absorbing liquid 5 selectively absorbs SO ₂ in the exhaust gas and generates calcium sulfite. The absorption liquid 5 that has generated calcium sulfite is temporarily stored in the circulation tank 6, and while being stirred by the oxidizing stirrer 7, calcium sulfite is oxidized by oxygen in the air supplied from the air blowing pipe 8, and calcium sulfate (gypsum)
Generate Part of the absorbent 5 in the circulation tank 6 where calcium carbonate and gypsum coexist is sent to the spray nozzle 13 again by the absorbent circulation pump 4, and part of the waste liquid treatment / plaster (not shown) is drawn from the absorbent extraction pipe 10. It is sent to the collection system. Among the absorption liquids 5 atomized by the spray from the spray nozzle 13, those having a small droplet diameter are accompanied by the exhaust gas, but are collected by the mist eliminator 9 provided in the outlet duct 3.

In a recent desulfurization apparatus, the stirrer 7 and the air blowing pipe 8 are installed at a lower position than in the prior art in order to reduce the tower height of the absorption tower body 1, and the liquid depth of the circulation tank 6 is lowered. The suction pipe 1 of the absorbent circulation pump 4
4, the air bubbles 16 blown from the air blowing pipe 8 are sucked into the absorbent circulation pump 4 via the suction pipe 14. Therefore, in the prior art, as shown in FIG. 4, a baffle plate 15 is installed near the suction pipe 14 in the circulation tank 6, and the absorbing liquid 5 is sucked through the opening above the baffle plate 15, and By setting the descending speed of the absorbing liquid 5 to be equal to or lower than the rising velocity of the bubbles 16, the suction of the bubbles 16 into the absorbing liquid circulating pump 4 is reduced.

However, with recent diversification of fuels, intensification of environmental regulations, energy saving, and the like, strict operating conditions have been required for desulfurization apparatuses. It is becoming a condition that is easily sucked into the circulation pump 4. (1) An increase in the amount of circulating liquid in the exhaust gas due to an increase in the concentration of SO _{2 in} the exhaust gas increases the liquid descending speed in the circulation tank 6, and increases the amount of bubbles 16 due to an increase in the amount of oxidized air. Minimization of bubbles 16 due to an increase in salt concentration in absorbent 5 due to a reduction in the amount of water discharged from the desulfurization device. Foam layer 1 by exhaust gas entrainment
Formation of 7 Therefore, it is necessary to take measures to prevent the bubbles 16 from being sucked into the absorbent circulating pump 4 even under the conditions (1) to (3).

FIG. 5 shows a desulfurization apparatus provided with a two-chamber absorption tower. A partition plate 19 is installed in the absorption tower main body 1 of the two-chamber absorption tower of the desulfurization apparatus shown in FIG. 5, and the space in the absorption tower main body 1 is divided into two chambers. , The exhaust gas introduced from the inlet duct 2 is blocked by the partition plate 19, rises in the upflow area 20, reverses at the top of the tower, and then descends in the downflow area 21. . During this time, the upflow region 20 and the downflow region 2
In 1, the absorption liquid 5 containing calcium carbonate sent from the absorption liquid circulation pump 4 is jetted from the spray nozzles 13 provided in the respective regions 20 and 21, and gas-liquid contact between the absorption liquid 5 and exhaust gas is performed.

At this time, SO _{2 in the} exhaust gas is absorbed by the absorbing liquid 5.
Is selectively absorbed and oxidized in the circulation tank 6 to produce calcium sulfate (gypsum). A part of the absorbent 5 in the circulation tank 6 where calcium carbonate and gypsum coexist is sent to the spray nozzle 13 again by the absorbent circulation pump 4 and a part is drawn from the absorbent extraction pipe 10 provided in the suction pipe 14. It is sent to a waste liquid treatment and gypsum recovery system not shown. Among the absorption liquids 5 atomized by the spray from the spray nozzle 13, those having a small droplet diameter are accompanied by the exhaust gas, but are collected by the mist eliminator 9 provided in the outlet duct 3. The partition plate 19 is for exclusively partitioning the space of the absorption tower main body 1, and the lower end of the partition plate 19 is slightly
It is only immersed in the stored absorbent.

In a desulfurization apparatus provided with a two-chamber type absorption tower in which an ascending flow region 20 and a descending flow region 21 of exhaust gas are formed by a partition plate 19, mist trapping of the mist eliminator 9 due to gas drift in the absorption tower outlet duct 3. There is a concern that the collection performance may decrease. Therefore, in the two-chamber absorption tower, it is desirable to be able to prevent the bubbles 16 from being sucked into the absorbent circulation pump 4 and at the same time to suppress the gas drift in the outlet duct 3.

[0012]

In the above prior art, the suction of the air bubbles 16 from the absorbing liquid suction pipe 14 to the absorbing liquid circulating pump 4 is not sufficiently considered, and the absorbing liquid from the circulating tank 6 to the spray nozzle 13 is not taken into consideration. There was a problem that the desulfurization performance was reduced due to a decrease in the circulation amount of No. 5.

An object of the present invention is to provide a wet flue gas desulfurization apparatus having a low operating cost by suppressing suction of air bubbles into a circulation pump and preventing a decrease in desulfurization performance without greatly increasing equipment costs. To get.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide an absorbent circulating pump provided on a wall of a circulating tank, the upper end of which is protruded to a liquid level near the suction pipe, and the lower end thereof is connected to the bottom of the circulating tank. The circulation tank is divided into two by installing a baffle plate provided with an absorption liquid circulation opening between, and air is supplied to the absorption liquid on the oxidation region side in the circulation tank where the suction pipe does not exist in the two divided regions. The droplets that fall into the absorption liquid on the non-oxidizing area side in the circulation tank where the blowing and suction pipes are present are collected in the upper space of the non-oxidizing area,
This is achieved by sending all the recovered absorbent to the oxidized region side.

That is, the present invention has the following configuration. (1) By introducing the exhaust gas discharged from a combustion device such as a boiler and bringing the exhaust gas into gas-liquid contact with the absorbing liquid ejected from spray nozzles installed in a plurality of stages in the gas flow direction of the gas absorbing section, the exhaust gas is discharged. An absorption tower for treating sulfur oxides, a circulation tank provided at the lower portion of the absorption tower for storing the absorption liquid, and an absorption liquid suction pipe provided on the wall surface of the circulation tank and supplying the absorption liquid to the spray nozzle for circulation. In a wet flue gas desulfurization device equipped with piping, in the circulation tank near the wall of the circulation tank to which the absorption liquid suction piping is connected,
The baffle plate is arranged with the upper end protruding to the liquid level of the stored absorbing liquid, and an interval (absorbing liquid flow section) for the flowing of the absorbing liquid is provided between the lower end and the bottom of the circulation tank. Divide the absorbent storage part in the tank into two parts,
In the absorption liquid storage part divided into two, the air blowing pipe is arranged on the circulation tank wall on the oxidation area side where the suction pipe is not connected to the wall, and the non-oxidation area side where the suction pipe is connected to the wall. A wet-type flue gas desulfurization apparatus comprising: means for collecting the absorbing liquid to be dropped into the non-oxidizing area above the non-oxidizing area, and sending the collected absorbing liquid into the circulation tank on the oxidizing area side.

(2) An inlet duct for introducing exhaust gas discharged from a combustion device such as a boiler in a substantially horizontal direction and an outlet duct for discharging purified exhaust gas in a substantially horizontal direction are provided, between the inlet duct and the outlet duct. In order to divide the exhaust gas channel into two chambers on the inlet duct side and the outlet duct side, a vertical partition plate having an opening on the ceiling side is provided. A rising flow region in which the exhaust gas introduced from the duct flows upward and a descending flow region in which the exhaust gas flows downward toward the outlet duct after being inverted at the opening on the ceiling side are formed, and the absorbing liquid slurry that is ejected forms the exhaust gas and the upward flow. An absorption tower for treating sulfur oxides in exhaust gas, wherein a spray nozzle is provided in each of the above regions so as to make countercurrent contact in the region and cocurrent contact in the downward flow region; and a spray nozzle below the absorption tower. In a two-chamber wet-type flue gas desulfurization system equipped with a circulation tank that stores the absorption liquid slurry that is jetted out, an absorption liquid suction pipe that supplies the absorption liquid to the spray nozzle is provided on the wall of the circulation tank below the outlet duct. In the circulation tank near the wall of the circulation tank to which the absorption liquid suction pipe is connected, the upper end protrudes to the liquid level of the stored absorption liquid, and the space between the lower end and the bottom of the circulation tank is used for circulation of the absorption liquid. A baffle plate is provided at intervals, and the absorption liquid storage portion in the circulation tank is divided into two by the baffle plate. Of the two divided absorption liquid storage portions, the oxidation region side where the suction pipe is not connected to the wall surface An air blowing pipe is arranged on the wall of the circulation tank, and the suction pipe is collected in the upper space of the non-oxidizing area, and the absorbing liquid droplets which are about to fall to the non-oxidizing area connected to the wall are collected and recovered. Wet flue gas desulfurization apparatus of the absorption liquid comprising means for sending to the circulation tank of the oxidation region side.

In the wet flue gas desulfurization apparatus of the present invention,
Recover the absorbing liquid that is about to fall to the non-oxidized area side,
A stepped louver can be used in the upper space of the non-oxidized region as a means for sending the recovered absorbent into the circulation tank on the oxidized region side.

[0018]

In the prior art, the cause of air bubbles in the absorbing liquid in the circulation tank being sucked into the absorbing liquid circulation pump through the absorbing liquid suction pipe provided on the wall of the circulation tank is the installation position of the absorbing liquid suction pipe. It is in. The air bubbles blown from the air blowing pipe basically rise in the stored absorption liquid in the circulation tank, and all the air bubbles are collected near the liquid surface, so that there are many air bubbles in the upper part of the circulation tank. In addition, a foam layer is present on the liquid surface, and bubbles rising from below are taken into the foam layer, so that the foam layer further increases in thickness.

In the prior art, since the absorbing liquid is to be sucked from the upper wall surface of the circulation tank in which the bubbles and the foam layer are mixed, the descending flow rate of the absorbing liquid in the baffle plate is set to be equal to or less than the rising rate of the average bubble diameter. Even so, finer bubbles will be inhaled.

However, according to the present invention, since the absorbing liquid circulation section is provided on the bottom side of the baffle plate, the absorbing liquid can be sucked from the bottom of the circulation tank where the number of bubbles is the least. Further, since the absorbent in the circulation tank does not form a downward flow in the vicinity of the absorbent circulating portion on the lower end side of the baffle plate, bubbles are less likely to be sucked.

In addition, since a stepped louver for receiving droplets falling on the upper part of the suction pipe and flowing the liquid to the outside of the baffle plate is installed in the upper space of the baffle plate, a foam layer is formed on the liquid surface in the baffle plate. Not formed. If the absorbent is not newly supplied into the baffle plate, the gypsum concentration in the absorbent in the baffle plate is kept low, so that the amount of gypsum deposited on the bottom inside the baffle plate when the operation of the desulfurization device is stopped is small. That is, it is possible to prevent trouble at the time of restarting the desulfurization device.
Therefore, it is not necessary to provide a preliminary stirrer in the baffle plate for preventing the gypsum from settling when the operation of the desulfurization device is stopped.

Further, when the present invention is applied to a two-chamber type desulfurization apparatus, the uneven louver portion functions as a flow straightening plate, so that the gas drift at the mist eliminator inlet can be reduced.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional side view of an absorption tower in which a baffle plate and an uneven louver provided with an absorption liquid circulation section provided on the bottom side of a circulation tank according to an embodiment of the present invention are combined. 2 and 3 show another embodiment of the present invention, and FIG. 2 is a schematic side sectional view of an absorption tower when the present invention is applied to a two-chamber desulfurization apparatus. FIG. 3 shows a simulation of the gas flow in the outlet duct in FIG.

The wet flue gas desulfurization apparatus shown in FIGS.
Similar to that of the prior art, mainly the absorption tower main body 1, the inlet duct 2, the outlet duct 3, the absorbent circulation pump 4, the circulation tank 6, the stirrer 7, the air injection pipe 8, the mist eliminator 9, the absorption liquid discharge pipe. 10, a circulation pipe 11, a spray header 12, a spray nozzle 13, a suction pipe 14, and the like. A plurality of spray nozzles 13 are provided in a cross section orthogonal to the gas flow, and a plurality of spray nozzles are provided in the gas flow direction. Further, the stirrer 7 and the air blowing pipe 8 are installed in a circulation tank 6 in which the absorbing liquid 5 stays, and the mist eliminator 9 is installed in the outlet duct 3.

In the wet flue gas desulfurization apparatus shown in FIGS. 1 to 3,
The point different from the wet flue gas desulfurization apparatus of the prior art is that the circulation tank 6
The baffle plate 15 is disposed so as to leave a space (absorbent liquid circulation section) through which the absorbent can pass in the absorbent storage section on the bottom side of the baffle plate 15. Louver 1 at the top
8 is provided.

In the above-mentioned wet flue gas desulfurization apparatus of the present invention, since the absorbent flow section is provided on the bottom side of the baffle plate 15, the absorbent 5 is sucked into the circulation pipe 11 from the bottom of the circulation tank 6 having the least number of bubbles 16. It can be sucked into the pipe 14. Also, since the absorbent does not form a downward flow in the vicinity of the absorbent flow section at the lower end of the baffle plate 15,
The bubbles 16 are hardly sucked.

Further, since a stepped louver 18 for receiving the liquid drops falling on the upper part of the suction pipe 14 and flowing the liquid to the outside of the baffle plate 15 is installed in the upper space of the baffle plate 15, the louver 18 is partitioned by the baffle plate 15. A foam layer 17 is formed on the liquid surface of the absorption liquid storage section in the circulation tank 6 that receives the fallen absorption liquid, but the absorption layer is located in a space surrounded by the baffle plate 15, the stepped louver 18, and the wall surface of the circulation tank 6. The foam layer 17 is not formed on the liquid surface of the absorbing liquid storage portion in the liquid region (non-oxidized region).

If no new absorbing liquid 5 is supplied to the absorbing liquid 5 in the non-oxidized region, the absorbing liquid 5
Since the gypsum concentration in the inside is kept low, the amount of gypsum that accumulates on the bottom in the baffle plate 15 when the operation of the desulfurization device is stopped is reduced, and troubles when restarting the desulfurization device can be prevented. Therefore, it is not necessary to provide a pre-stirrer in the non-oxidized area for preventing the gypsum from settling when the operation of the desulfurization apparatus is stopped.

The embodiment shown in FIGS. 2 and 3 differs from the embodiment shown in FIG. 1 in that the present invention is applied to a two-chamber desulfurization apparatus. The two-chamber desulfurizer has the same structure as that of the prior art shown in FIG.
The same components as those used in the absorption tower shown in FIG.

A partition plate 19 is provided in the absorption tower main body 1,
Although the space inside the absorption tower main body 1 is divided into two chambers, since the outlet duct 3 is provided at substantially the same height as the inlet duct 2, the exhaust gas introduced from the inlet duct 2 is blocked by the partition plate 19, After ascending in the upflow area 20 and reversing at the top of the tower, it descends in the downflow area 21. During this time, in the upflow region 20 and the downflow region 21, the absorption liquid 5 containing calcium carbonate sent from the absorption liquid circulation pump 4 is jetted from the spray nozzles 13 provided in the respective regions 20 and 21, and the absorption liquid 5 And gas-liquid contact of the exhaust gas.

At this time, the SO _{2 in the} exhaust gas is
Is selectively absorbed and oxidized in the circulation tank 6 to produce calcium sulfate (gypsum). A part of the absorbent 5 in the circulation tank 6 where calcium carbonate and gypsum coexist is sent to the spray nozzle 13 again by the absorbent circulation pump 4 and a part is drawn from the absorbent extraction pipe 10 provided in the suction pipe 14. It is sent to a waste liquid treatment and gypsum recovery system not shown. Among the absorption liquids 5 atomized by the spray from the spray nozzle 13, those having a small droplet diameter are accompanied by the exhaust gas, but are collected by the mist eliminator 9 provided in the outlet duct 3.

The absorption tower main body 1 shown in FIG.
Are provided at substantially the same low height as the inlet duct 2, the supporting steel frames (not shown) of the mist eliminator 9 and the outlet duct 3 are low and simple, and the heat exchanger (reheating side) The length of the duct for connecting to the (not shown) can be reduced.

In a desulfurization apparatus provided with a two-chamber absorption tower in which an upflow region 20 and a downflow region 21 of exhaust gas are formed by a partition plate 19, the absorption liquid on the bottom side of the circulation tank 6 below the downflow region 21 The baffle plate 15 is arranged so as to leave a space through which the absorbing liquid 5 can pass in the storage part, and a stepped louver 18 is provided at the top of the baffle plate 15.

In the above-mentioned wet flue gas desulfurization apparatus of the present invention, since the absorbent flow section is provided on the bottom side of the baffle plate 15, the absorbent 5 is sucked into the circulation pipe 11 from the bottom of the circulation tank 6 having the least number of bubbles 16. It can be sucked into the pipe 14. Also, since the absorbent does not form a downward flow in the vicinity of the absorbent flow section at the lower end of the baffle plate 15,
The bubbles 16 are hardly sucked.

Further, a stepped louver 18 for receiving the liquid drops falling on the upper part of the suction pipe 14 and flowing the liquid to the outside of the baffle plate 15 is provided in the upper space of the baffle plate 15, so that the louver 18 is partitioned by the baffle plate 15. A foam layer 17 is formed on the liquid surface of the absorption liquid storage section in the circulation tank 6 that receives the fallen absorption liquid, but the absorption layer is located in a space surrounded by the baffle plate 15, the stepped louver 18, and the wall surface of the circulation tank 6. The foam layer 17 is not formed on the liquid surface of the reservoir in the liquid region (non-oxidized region). Since the absorbent storage portion surrounded by the baffle plate 15, the stepped louver 18 and the wall of the circulation tank is a non-oxidized region, there is an effect of preventing air bubbles from being sucked into the absorbent circulation pump 4.

Further, as shown in FIG. 3, the stepped louver 18 placed below the downflow area 21 corresponding to the upper space of the baffle plate 15 functions as a rectifying plate.
Gas drift in the outlet duct 3 is suppressed, and a decrease in the mist collection performance of the mist eliminator 9 can be prevented.

[0037]

According to the present invention, the absorption liquid is provided in the absorption liquid suction pipe for circulating and supplying the absorption liquid from the spray nozzle of the absorption tower from the circulation tank. The desulfurization performance does not decrease due to the decrease in the amount. Further, in the two-chamber type desulfurization device, it is possible to prevent gas drift in the outlet duct. Furthermore, since the amount of gypsum accumulated in the non-oxidized area surrounded by the baffle plate, the stepped louver and the circulation tank wall when the operation of the desulfurization apparatus is stopped can be reduced, the stirrer in the non-fall area of the spray-absorbed liquid is omitted. It is also possible.

[Brief description of the drawings]

FIG. 1 is a schematic side cross-sectional view of an absorption tower in which a baffle plate and an uneven louver provided with an absorption liquid circulation section provided on a tank bottom side according to an embodiment of the present invention are combined.

FIG. 2 is another embodiment of the present invention and is a schematic side sectional view of an absorption tower when the present invention is applied to a two-chamber desulfurization apparatus.

FIG. 3 is a view showing a gas flow in an outlet duct in the embodiment of FIG. 2;

FIG. 4 is a schematic side sectional view of an absorption tower in a conventional wet flue gas desulfurization apparatus.

FIG. 5 is a schematic side sectional view of an absorption tower in a conventional two-chamber desulfurization apparatus.

FIG. 6 is a diagram showing a gas flow in an outlet duct in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Absorption tower main body 2 Inlet duct 3 Outlet duct 4 Absorbent circulation pump 5 Absorbent 6 Circulation tank 7 Stirrer 8 Air blowing pipe 9 Mist eliminator 10 Absorbent extraction pipe 11 Circulation pipe 12 Spray header 13 Spray nozzle 14 Suction pipe 15 Baffle plate 16 Bubbles 17 Foam layer 18 Uneven louver 19 Partition plate 20 Upflow area 21 Downflow area

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Motoomi Iwazuki 3-36 Takara-cho, Kure-shi, Hiroshima Prefecture Babcock Inside Hitachi Kure Research Laboratory (72) Inventor Atsushi Katagawa 6-9 Takara-cho, Kure-shi, Hiroshima Prefecture Babcock F-term in Kure Works, Hitachi, Ltd. (reference) 4D002 AA02 AC01 BA02 CA01 DA05 DA16 EA11 FA03 HA10 4D020 AA06 BA02 BA09 BB03 CB25 CC04 CC06

Claims (4)

[Claims] An exhaust gas discharged from a combustion device such as a boiler is introduced, and the absorbent and the exhaust gas injected from spray nozzles installed in a plurality of stages in a gas flow direction of a gas absorbing portion are brought into gas-liquid contact with each other, An absorption tower for treating sulfur oxides in exhaust gas, a circulation tank provided at a lower portion of the absorption tower for storing the absorption liquid, and an absorption tank provided on a wall surface of the circulation tank and supplying the absorption liquid to the spray nozzle by circulation. In a wet-type flue gas desulfurization device having a liquid suction pipe, an upper end protrudes up to a liquid level of the stored absorption liquid in a circulation tank near a circulation tank wall to which the absorption liquid suction pipe is connected, and a lower end thereof. A baffle plate is arranged with an interval for circulation of the absorbent between the bottom of the circulation tank and the baffle plate to divide the absorbent reservoir in the circulation tank into two parts. Of these, the air suction pipe is placed on the circulation tank wall on the oxidation area side where the absorption liquid suction pipe is not connected to the wall, and the absorption liquid that is about to fall to the non-oxidation area side where the suction pipe is connected to the wall A wet-type flue gas desulfurization apparatus, comprising: means for recovering water in the upper space of the non-oxidizing area and sending the recovered absorbent into the circulation tank on the oxidizing area side. 2. A stepped louver is provided in the upper space of the non-oxidation area as a means for collecting the absorbing liquid which is going to fall to the non-oxidation area side and sending the collected absorption liquid into the circulation tank on the oxidation area side. The wet flue gas desulfurization device according to claim 1, wherein 3. An inlet duct for introducing exhaust gas discharged from a combustion device such as a boiler in a substantially horizontal direction and an outlet duct for discharging purified exhaust gas in a substantially horizontal direction are provided between the inlet duct and the outlet duct. An exhaust gas channel is provided, and a vertical partition plate having an opening on the ceiling side is provided to divide the exhaust gas channel into two chambers on the inlet duct side and the outlet duct side, and the partition plate is used to enter the inlet duct. A rising flow region in which the exhaust gas introduced from above flows upward and a descending flow region in which the exhaust gas flows downward toward the outlet duct after being reversed at the opening on the ceiling side, and the absorbing slurry ejected is the exhaust gas and the upward flow region. An absorption tower for treating sulfur oxides in exhaust gas provided with spray nozzles in each of the above regions so as to make countercurrent contact with each other in a downward flow region and a spray nozzle below the absorption tower from the spray nozzle. In a two-chamber wet-type flue gas desulfurization device provided with a circulation tank for storing the discharged slurry of the absorption liquid, an absorption liquid suction pipe for circulating the absorption liquid to the spray nozzle is provided on the wall of the circulation tank below the outlet duct, In the circulation tank near the wall surface of the circulation tank to which the absorption liquid suction pipe is connected, the upper end protrudes to the liquid surface of the stored absorption liquid, and the space for the circulation of the absorption liquid between the lower end and the bottom surface of the circulation tank. The baffle plate is installed and the absorption liquid storage portion in the circulation tank is divided into two by the baffle plate, and the absorption pipe of the absorption liquid storage portion in which the suction pipe is not connected to the wall surface is not connected to the wall surface. An air blowing pipe is arranged on the wall of the circulation tank, and the absorbing liquid droplets which are about to fall to the non-oxidizing area side where the suction pipe is connected to the wall are collected in the upper space of the non-oxidizing area. A wet flue gas desulfurization device comprising means for sending a liquid into a circulation tank on the oxidation region side. 4. A stepped louver is provided in the upper space of the non-oxidation area as a means for collecting the absorbing liquid which is going to fall to the non-oxidation area side and sending the collected absorption liquid into the circulation tank on the oxidation area side. The wet flue gas desulfurization device according to claim 1, wherein