JPH08276114A - Wet flue gas desulfurization device - Google Patents

Abstract

PURPOSE: To obtain a desulfurization device which reduces the power cost for an absrobant liquid circulation system by the low back pressure of a spray without deterioration of the desulfurization rate, minimizes the cost of a spray nozzle material and operating/equipment expenses and improves desulfurization performance. CONSTITUTION: In a spray reaction part which absorbs SO2 by contact between an absorptive liquid and SO2 contained in an exhaust gas, the atomization of the absorptive liquid sprayed from a nozzle 11 at a low spray back pressure is promoted using the kinetic energy of the exhaust gas introduced from an inlet duct 2 by setting the spray back pressure lower than in a conventional method and increasing a gas flow velocity. For example, the back pressure of the nozzle 11 is set at 0.5kg/cm<2> or lower and the gas flow velocity in the neighborhood of the nozzle 11 is set to 10m/s or higher. Further, when setting the gas flow velocity near the nozzle 11 to 10m/s or higher, it is possible to enhance the effects to promote the atomization of the absorptive liquid by injecting from the nozzle 11 a group of liquid droplets with a large average diameter than the average diameter of those obtained by a formula dp =0.2UG.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to SO in a boiler exhaust gas.
_It relates to a wet flue gas desulfurization device that removes ₂ , especially the wet flue gas desulfurization device that can reduce the power cost of the absorbent circulation pump by lowering the spray back pressure and further reduce the construction cost such as installing a spray nozzle. is there.

[0002]

2. Description of the Related Art Sulfur oxides in flue gas generated by combustion of fossil fuels, especially sulfur dioxide (SO ₂ ) in thermal power plants is a main cause of environmental problems such as air pollution and acid rain. It is one of these, and it has been desired in recent years that flue gas desulfurization equipment spreads on a global scale.

The current desulfurization system is dominated by the wet method based on the limestone-gypsum method, and the spray method, which has the most proven results and is highly reliable, is widely adopted all over the world. This spray desulfurization device has a high desulfurization performance and is an almost established technology, but since it is expensive, its penetration rate in developing countries is still low. Therefore, in order to increase the penetration rate of desulfurization equipment worldwide, it is important to significantly reduce the equipment cost and operating cost of the desulfurization equipment.

FIG. 9 shows an example of a conventional wet type flue gas desulfurization apparatus using a spray method. The desulfurization apparatus mainly includes an absorption tower body 1, an inlet duct 2, an outlet duct 3, a spray nozzle 4,
The absorption liquid circulation pump 5, the oxidation tank 6, the stirrer 7, the air blowing pipe 8, the mist eliminator 9, and the like.
A plurality of spray nozzles 4 are arranged in a direction orthogonal to the gas flow,
Furthermore, multiple stages are installed in the gas flow direction. Further, the agitator 7 and the air blowing pipe 8 are installed in the oxidation tank 6 in the lower part of the absorption tower where the absorbing liquid stays, and the mist eliminator 9 is installed in the outlet duct 3. Exhaust gas discharged from a boiler (not shown) is introduced into the absorber main body 1 from the inlet duct 2 by a desulfurization fan (not shown) and discharged from the outlet duct 3. During this time, the desulfurization tower is sprayed with the absorption liquid containing calcium carbonate, which is sent from the absorption liquid circulation pump 5, from the plurality of spray nozzles 4, and the absorption liquid and the exhaust gas are brought into gas-liquid contact. At this time, the absorbing liquid is S in the exhaust gas.
It selectively absorbs O ₂ and produces calcium sulfite.
The absorption liquid that has generated calcium sulfite is accumulated in the oxidation tank 6, and while being stirred by the agitation stirrer 7, oxygen in the air supplied from the air blowing pipe 8 oxidizes the calcium sulfite in the absorption liquid to generate gypsum. . A part of the absorption liquid in the oxidation tank 6 in which calcium carbonate and gypsum coexist is sent to the spray nozzle 4 again by the absorption liquid circulation pump 5, and a part of the absorption liquid is taken out from the absorption liquid withdrawing pipe 10 to recover waste liquid / gypsum (not shown). Sent to the system. In the absorbing liquid atomized by spraying from the spray nozzle 4,
Those with a small droplet diameter are entrained in the exhaust gas and exit duct 3
It is collected by the mist eliminator 9 provided in the.

When the desulfurization apparatus as described above is applied to exhaust gas having a high SO ₂ concentration, in order to obtain high desulfurization performance, the amount of absorbing liquid sprayed per unit amount of gas (liquid-gas ratio) should be higher than usual. It is necessary to set it, and the power of the absorbent circulating pump 5 required for circulating the absorbent increases.

As mentioned above, it has been particularly demanded in recent years to reduce the operating cost of the desulfurizer. As one of the measures, it is conceivable to reduce the pump power, but in order to reduce the pump power, the pressure applied to the spray nozzle 4 at the time of spraying the absorption liquid, that is, the spray back pressure is reduced to reduce the absorption liquid circulation pump 5. It is necessary to reduce such pressure. However, if the spray back pressure is lowered while leaving other operating conditions unchanged, atomization of the droplets is hindered, and the diameter of the droplets to be sprayed increases. When the droplet size becomes large, the gas-liquid contact area, which has a great influence on the SO ₂ absorption rate, decreases, which causes a decrease in desulfurization performance.

Further, in the present wet flue gas desulfurization apparatus, the material of the nozzle of the spray nozzle 4 which is generally used is a material having high wear resistance. This is because the spray back pressure of the spray nozzle 4 is as high as 0.8 to 1.0 kg / cm ² in the commonly used wet flue gas desulfurization apparatus, so that the liquid flow velocity inside the spray nozzle 4 is high and This is because it is necessary to consider wear of the nozzle material due to existing gypsum particles, and a material having high wear resistance such as SiC must be used. However, since the spray nozzle 4 made of SiC is expensive, not only does it not meet the demands of the times, but it is weak against impact and easily broken.
Therefore, it cannot be shipped with the spray nozzle 4 attached to the spray header in advance in the factory, and scaffolding is assembled at the time when the spray header is installed inside the absorption tower at the construction site of the desulfurization equipment, and work is done one by one. The present situation is that the spray nozzle 4 is attached by the hand of a worker.

From the above, in order to drastically reduce the operating cost of the wet flue gas desulfurization device, the spray back pressure is lowered and the power of the absorption liquid circulation pump 5 is reduced by devising such that the desulfurization performance is not deteriorated. It is important to reduce the cost and reduce the cost of the spray nozzle material.

[0009]

In the above-mentioned prior art, regarding the method of reducing the operating cost and equipment cost of the wet desulfurization device, the power cost of the absorbent circulating pump required for circulating the absorbent by reducing the spray back pressure is reduced. No consideration has been given to the reduction and cost reduction of the material of the spray nozzle 4 due to the reduction of the back pressure. Especially, it is applied to the exhaust gas with a high SO ₂ concentration such as the exhaust gas from the combustion device used overseas. However, in order to obtain a desulfurization device that can exhibit high desulfurization performance, it is necessary to increase the absorption liquid circulation amount and increase the liquid-gas ratio, which increases operating costs due to an increase in the power cost of the absorption liquid circulation pump. There was a problem.

The object of the present invention is to reduce the power cost of the absorbent circulation pump by reducing the back pressure of the spray without lowering the desulfurization rate and the cost of the spray nozzle material, and to purify exhaust gas having a high SO ₂ concentration. The purpose is to obtain a desulfurization device that can cope with the above, has low operating costs and equipment costs, and has high desulfurization performance.

[0011]

The above object of the present invention can be achieved by the following constitutions. That is, an exhaust gas passage for flowing exhaust gas discharged from a combustion device such as a boiler is provided in the upper part of an absorbing liquid tank holding the absorbing liquid, and jetted from a spray nozzle installed in at least one stage in the gas flow direction of the exhaust gas passage. By contacting the absorbing liquid with the exhaust gas,
In a wet flue gas desulfurization device equipped with an absorption tower that treats sulfur oxides in exhaust gas by dropping the absorption liquid into an absorption liquid tank, a spray nozzle that atomizes the absorption liquid using the kinetic energy of the exhaust gas is used as the exhaust gas. It is a wet flue gas desulfurization device installed in the flow path.

In the wet flue gas desulfurization apparatus of the present invention, the back pressure of the spray nozzle for ejecting the absorbing liquid is 0.5 kg / cm ² or less in the region where the absorbing liquid is atomized by utilizing the kinetic energy of the exhaust gas. It is desirable that the gas flow velocity near the spray nozzle be 10 m / s or more. Also, the gas flow rate U _G near the spray nozzle is 10 m /
When set to s or more, it is desirable to eject a droplet group having an average diameter larger than the average diameter d _{p of the} droplet obtained from the relational expression of d _p = 0.2 U _G from the spray nozzle.

The above object of the present invention can be achieved by the following constitutions. That is, an exhaust gas passage for flowing exhaust gas discharged from a combustion device such as a boiler is provided in the upper part of an absorbing liquid tank holding the absorbing liquid, and jetted from a spray nozzle installed in at least one stage in the gas flow direction of the exhaust gas passage. In the wet flue gas desulfurization device equipped with an absorption tower that treats the sulfur oxide in the exhaust gas by bringing the absorbed liquid and the exhaust gas into contact with each other and dropping the absorption liquid into the absorption liquid tank, the kinetic energy of the exhaust gas is In addition to the spray nozzle that atomizes the ejected absorbing liquid by using it, the kinetic energy of exhaust gas is not used, and when the absorbing liquid is ejected from the spray nozzle exclusively, the disturbance of the liquid film formed like an umbrella centering on the spray nozzle It is a wet flue gas desulfurization device in which a spray nozzle that atomizes the absorbing liquid by the shearing force generated by the growth of is installed in the exhaust gas passage.

In the wet flue gas desulfurization apparatus of the present invention, the back pressure of the spray nozzle for ejecting the absorbing liquid is 0.5 kg / cm ² or less in the region where the absorbing liquid is atomized by utilizing the kinetic energy of the exhaust gas. The flow velocity of the gas in the vicinity of the spray nozzle is set to 10 m / s or more and the turbulence of the liquid film formed in an umbrella shape around the spray nozzle is mainly used when the absorbing liquid is ejected from the spray nozzle without using the kinetic energy of the exhaust gas. The back pressure of the spray nozzle that atomizes the absorbing liquid by the shearing force generated by the growth of
/ Cm ² or more is desirable.

Further, in the above wet flue gas desulfurization apparatus of the present invention, a liquid film formed in an umbrella shape centering on the spray nozzle when the absorbing liquid is ejected exclusively from the spray nozzle without utilizing the kinetic energy of the exhaust gas. A liquid recovery device for recovering the absorption liquid ejected from the spray nozzle that atomizes the absorption liquid by the shearing force generated by the growth of turbulence is provided in the exhaust gas passage, and the absorption liquid recovered from the liquid recovery device is contained in the exhaust gas. A structure equipped with a liquid supply tank that supplies the spray nozzle that atomizes the jetted absorption liquid by using kinetic energy, or without using the kinetic energy of exhaust gas, the spray nozzle is used when the absorption liquid is jetted from the spray nozzle. The absorption force is absorbed only by the spray nozzle that atomizes the absorbing liquid by the shearing force generated by the growth of the turbulence of the liquid film formed like an umbrella as the center. Structure the absorption liquid in the liquid tank provided with a circularly supplying circulation system is desirable.

In any of the above wet flue gas desulfurization apparatus of the present invention, the exhaust gas passage in the absorption tower is formed in a vertical direction, or the exhaust gas passage in the absorption tower is formed in a non-vertical direction. Alternatively, the exhaust gas passage in the absorption tower may be formed in a vertical direction and a non-vertical direction.

[0017]

[Function] Although various factors affect the desulfurization performance of the wet flue gas desulfurization device, the area that contributes to the reaction between the gas and the absorbing liquid, that is, the gas-liquid contact area has a large effect. The larger the area, the higher the desulfurization performance. Therefore, if the spray back pressure is simply lowered in order to reduce the power cost of the absorption liquid circulation pump, the droplet diameter becomes coarse and the gas-liquid contact area decreases, leading to a decrease in desulfurization performance. However, if the gas flow velocity in the vicinity of the spray nozzle is increased as in the present invention, the atomization of the absorbing liquid when ejected from the spray nozzle is promoted.

In other words, when there is no gas flow in the vicinity of the spray nozzle or when the gas flow is small, when the absorbing liquid is ejected from the spray nozzle, shearing occurs due to turbulent growth of the liquid film formed in an umbrella shape around the spray nozzle. The absorption liquid is atomized by the force. However, when the gas flow velocity near the spray nozzle becomes high, the kinetic energy of the exhaust gas further increases the turbulence of the umbrella-shaped liquid film and causes a larger shearing force, so that the absorbing liquid is atomized into smaller particles.
When the kinetic energy of exhaust gas is used, the higher the gas flow velocity in the vicinity of the spray nozzle and the lower the spray back pressure, the easier the atomization. On the other hand, in the case of the conventional technique, the gas flow rate is 2 to 5 m / s and the spray back pressure is 0.8 kg / cm ² or more, and the droplets are not atomized under this condition. We have confirmed this through droplet size measurement using a Caesar and desulfurization experiments in a pilot plant.

FIG. 1 shows a spray nozzle (hollow cone type).
The atomization characteristics of the absorbing liquid when the gas flow velocity in the vicinity is changed are shown. When the spray back pressure is 0.8 kg / cm ² or more, the effect of atomization is not so remarkable, but the spray back pressure is 0.5
When the gas flow rate is increased below kg / cm ² , the droplets become smaller, and it can be seen that the effect of promoting atomization is greater as the spray back pressure is lower. That is, it can be said that larger droplets are more likely to be atomized. Therefore, under a high gas flow rate, the droplet does not become so large even if the spray back pressure is reduced.

As described above, from FIG. 1, the tendency of atomization of the droplet diameter of the absorbing liquid is large at the gas flow rate up to 10 m / s, and small at the gas flow rate above 10 m / s. It can be seen that by setting the gas flow velocity to about 10 m / s, it is possible to maximize the atomization effect of the droplet size of the absorbing liquid by the kinetic energy of the gas.

[0021] However, was operated in the prior art, such as gas flow rate 3m / s, as in the present invention the conditions of spray back pressure 0.8 kg / cm ^2, such as gas flow rate 14m / s, spray back pressure 0. When it is set to 1 kg / cm ² , the droplet size becomes smaller due to the acceleration of atomization, but the droplet size is 1.4 times smaller than the conventional one.
Since it is twice as large, it has about 70
It decreases to about%.

However, the desulfurization performance is not determined only by the gas-liquid contact area, but is proportional to the product of the gas-liquid contact area and the overall mass transfer coefficient K _G , which indicates the ease of SO ₂ absorption. Fig. 2 shows the relationship between the gas flow velocity U _G and the overall mass transfer coefficient K _{G. When} the gas flow velocity U _G is increased, the overall mass transfer coefficient K _G also increases, and the gas flow velocity of 3 m / s becomes 14 m / s. If it increases, the overall mass transfer coefficient K _G shows a value about twice. Therefore, since the decrease in the gas-liquid contact area can be compensated by the increase in the overall mass transfer coefficient K _G , the desulfurization rate does not decrease and
Desulfurization performance equal to or higher than conventional can be obtained.

The term "atomization of droplets" as used herein means that 5% or more of all the droplets by weight are atomized, and droplets having a distribution larger than the average diameter. It means atomizing.

If the spray back pressure can be reduced as described above, the power cost of the absorbent circulation pump can be reduced,
It is possible to significantly reduce the operating cost of the desulfurizer. As a secondary effect, the lower the back pressure of the spray, the slower the flow rate of the absorbing liquid in the spray nozzle. Therefore, the wear of the spray nozzle material due to the gypsum particles present in the absorbing liquid is reduced, and the wear resistance of SiC or the like is reduced. It is not necessary to use a highly flexible material as the nozzle material, and a metallic material can be used. Since the metal material is more resistant to impact and less likely to be broken than SiC or the like, it can be shipped with the spray nozzle attached to the spray header in advance in the manufacturing plant, and the work of attaching the spray nozzle to the spray header on site can be eliminated. Therefore, the construction cost related to the equipment cost can be significantly reduced.

[0025]

EXAMPLE FIG. 3 shows a wet desulfurization apparatus of an example according to the present invention.
Shown in The desulfurization apparatus shown in FIG. 3 is similar to the absorption tower of the prior art shown in FIG. 9; the absorption tower body 1, the inlet duct 2, the outlet duct 3, the spray nozzle 4, the circulation pump 5, the oxidation tank 6,
It is composed of a stirrer 7, an air blowing tube 8, a mist eliminator 9, and the like. However, in this embodiment, the low back pressure spray nozzle 11 is installed in the ceiling portion of the upstream side of the absorption tower where the gas flow velocity is high, and the low back pressure pump 14 for the low back pressure spray nozzle 11 is provided. The absorption liquid sent from the low back pressure pump 14 is ejected from the low back pressure spray nozzle 11 and atomized by the high flow rate gas introduced from the gas inlet duct 2 to absorb SO ₂ in the exhaust gas.

In the case of this embodiment, since the inlet duct 2 is located below the absorption tower and the low back pressure spray nozzle 11 can be mounted at a low position, the power of the low back pressure pump 14 can be further reduced. Is. Further, in this embodiment, the low back pressure spray nozzle 11 is attached to the ceiling part,
It may be installed inside the absorption tower.

Another embodiment according to the present invention is shown in FIGS. In the desulfurization apparatus shown in FIGS. 4 to 8, members having the same functions as those of the desulfurization apparatus shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

In the embodiment shown in FIG. 4, the liquid recovery device 12 is provided in the vicinity of the inlet duct 2 of the tower body 1 above the high gas flow rate portion, and the absorption liquid ejected from the spray nozzle 4 by the station recovery device 12 is provided. Is collected, and the collected liquid is sent to a liquid supply tank 13 provided on the ceiling of the high gas flow velocity part, and the low back pressure spray nozzle 1 is supplied from this liquid supply tank 13.
The absorbing liquid is directly ejected through No. 1. If the liquid supply tank 13 has a liquid depth of about 2 m, it is possible to apply a spray back pressure of about 0.2 kg / cm ^{2 to the} low back pressure nozzle nozzle 11. Therefore, in the case of the present embodiment, the low back pressure pump 14 as in the embodiment of FIG. 3 is not required, and the equipment cost and the power cost related to the absorbent circulation system can be greatly reduced.

In the embodiment shown in FIGS. 5 and 6, a low back pressure spray nozzle 1 is installed in a horizontal absorption tower in which exhaust gas flows horizontally.
1 is applied. In FIG. 5, the low back pressure spray nozzle 11 is installed in the tower of the high gas flow rate part, and in FIG. 6, the low back pressure spray nozzle 11 is installed in the ceiling part of the high gas flow rate part. . In both cases, it is possible to obtain substantially the same effect as that of the embodiment shown in FIGS. It should be noted that, in FIG. 5, the jet direction of the absorbing liquid of the low back pressure spray nozzle 11 is set to be the same as the exhaust gas flow on the upstream side in the high gas flow velocity portion and opposite to the exhaust gas on the downstream side in the high gas flow velocity portion, so that the jet absorption The liquid is prevented from passing straight through the exhaust gas flow passage provided in the horizontal direction, and the chances of gas-liquid contact between the absorbing liquid and the exhaust gas are increased as much as possible.

In the embodiment shown in FIGS. 7 and 8, a low back pressure spray nozzle 11 is applied to a conventional absorption tower in which exhaust gas is passed in a vertical direction. In FIG. 7, the exhaust gas is made to flow from the lower part to the upper part, and the low back pressure spray nozzle 11 is installed in the direction opposite to the exhaust gas flow in the part where the exhaust gas rises at a high flow velocity of 10 m / s or more in the vertical direction. In FIG. 8, the exhaust direction of the low back pressure spray nozzle 11 is directed to the same direction as the flow direction of the exhaust gas at the portion where the exhaust gas vertically descends at a high flow velocity of 10 m / s or more.

The desulfurization apparatus shown in FIG. 8 is intended to improve the desulfurization performance and reduce the amount of mist scattered, while aiming at downsizing and cost reduction of the apparatus. That is, the horizontal ceiling wall surface of the tower body 1 is deformed to regulate the flow direction of the exhaust gas, and a space for changing the direction of the gas flow is provided between the upstream gas flow portion and the downstream gas flow portion, The gas flow velocity in the gas flow portion on the downstream side is made slower than the gas flow velocity in the gas flow portion on the upstream side, and at least one or more stages of spray nozzles 11 are provided upstream of the gas flow.
Further, the droplets ejected from the spray nozzle 11 on the upstream side are influenced by gravity and fall into the oxidation tank 6.

Further, the direction of the spray nozzle 11 and the jetting direction of the absorbing liquid in the embodiment shown in FIGS.
Not limited to the illustrated one, the jetting direction of the absorbing liquid from the spray nozzle 11 is at least one of the same direction and the opposite direction to the gas flow in the tower body 1 or a combination thereof is also within the scope of the present invention. include.

According to the above-mentioned embodiment, since the spray back pressure can be lowered without lowering the desulfurization performance, the power cost of the absorbent circulation system can be reduced and the operating cost of the desulfurizer can be greatly reduced. It will be possible. Further, when the spray back pressure becomes low, the flow rate of the absorbing liquid in the low back pressure spray nozzle 11 becomes slow, so that the wear of the spray nozzle constituent material due to the gypsum particles present in the absorbing liquid is reduced, and the wear resistance of SiC or the like is reduced. It is not necessary to use a high-quality material, and the spray nozzle 11 made of a metal material can be used. The metal material is SiC
Since it is more resistant to impacts and less likely to break than other products, it can be shipped with the spray nozzle 11 attached to the spray header in advance in the manufacturing plant, eliminating the work of attaching the spray nozzle 11 to the spray header at the desulfurization equipment construction site. it can. Therefore, the construction cost related to the equipment cost can be significantly reduced.

[0034]

According to the present invention, since the spray back pressure can be lowered without lowering the desulfurization performance, the power cost of the absorbent circulation system can be reduced and the operating cost of the desulfurizer can be greatly reduced. Further, when the spray back pressure is low, it is not necessary to use a high wear-resistant material as the spray nozzle material, and a spray nozzle made of a material resistant to impact such as a metal material can be used. Therefore, the spray nozzle is attached to the spray header in advance. Shipment and construction It is possible to significantly reduce the construction cost related to the equipment cost without complicated work at the site.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the action of the present invention in detail, and shows the relationship between the gas flow velocity in the spray section in the desulfurization apparatus and the size of droplets of the sprayed absorption liquid.

FIG. 2 is a diagram showing a relationship between a gas flow rate and an overall mass transfer coefficient representing the ease of SO ₂ absorption.

FIG. 3 is a diagram showing a wet flue gas desulfurization apparatus in which a low back pressure spray nozzle according to an embodiment of the present invention and a normal back pressure spray nozzle are combined.

FIG. 4 is a diagram showing a wet flue gas desulfurization apparatus according to an embodiment of the present invention when the low back pressure absorbing liquid circulation pump in the embodiment of FIG. 3 is omitted.

FIG. 5 is a diagram showing a wet desulfurization apparatus according to an embodiment of the present invention when a low back pressure spray is applied to a desulfurization apparatus having a horizontal absorption tower.

FIG. 6 is a view showing a wet desulfurization apparatus according to an embodiment of the present invention when a spray nozzle is attached to a ceiling portion in the embodiment of FIG.

FIG. 7 is a diagram showing a wet desulfurization apparatus according to an embodiment of the present invention when a low back pressure spray is applied to a spray section of a vertical absorption tower.

FIG. 8 is a diagram showing a wet desulfurization apparatus of another embodiment in which the gas flow direction is reversed in the embodiment of FIG.

FIG. 9 is a diagram showing a conventional wet desulfurization apparatus.

[Explanation of symbols]

1 ... Tower body, 2 ... Inlet duct, 3 ... Exit duct, 4 ... Spray nozzle, 5 ... Circulation pump, 6 ... Oxidation tank, 7 ... Stirrer, 8 ... Air blowing pipe, 9 ... Mist eliminator,
11 ... Low back pressure spray nozzle, 14 ... Low back pressure pump

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirofumi Yoshikawa 3-36 Takaracho, Kure-shi, Hiroshima Babcock Hitachi Ltd. Kure Laboratory (72) Noriaki Taniguchi 6-9 Takaracho, Kure-shi, Hiroshima Babcock Hitachi Ltd. Kure Factory

Claims (10)

[Claims] 1. An exhaust gas passage for flowing exhaust gas discharged from a combustion device such as a boiler is provided in an upper portion of an absorption liquid tank holding an absorption liquid, and at least one or more stages are installed in a gas flow direction of the exhaust gas passage. In a wet flue gas desulfurization device equipped with an absorption tower that treats the sulfur oxides in the exhaust gas by bringing the absorption liquid ejected from the spray nozzle into contact with the exhaust gas and dropping the absorption liquid into the absorption liquid tank, A wet flue gas desulfurization device, characterized in that a spray nozzle that atomizes the absorbing liquid by using kinetic energy is installed in the exhaust gas flow path. 2. The back pressure of a spray nozzle for ejecting the absorbing liquid is set to 0.5 kg / cm ² or less in a region where the absorbing liquid is atomized by utilizing the kinetic energy of exhaust gas, and the gas flow velocity in the vicinity of the spray nozzle is 10 m. / S or more, the wet flue gas desulfurization apparatus according to claim 1. 3. A gas flow rate U _G near the spray nozzle is set to 10
When set to m / s or more, a droplet group having an average diameter larger than the average diameter d _{p of the} droplet obtained from the relational expression of d _p = 0.2 U _G is ejected from the spray nozzle. The wet flue gas desulfurization apparatus according to claim 1. 4. An exhaust gas channel for flowing exhaust gas discharged from a combustion device such as a boiler is provided above an absorbent tank holding an absorbent, and at least one or more stages are installed in a gas flow direction of the exhaust gas channel. In a wet flue gas desulfurization device equipped with an absorption tower that treats the sulfur oxides in the exhaust gas by bringing the absorption liquid ejected from the spray nozzle into contact with the exhaust gas and dropping the absorption liquid into the absorption liquid tank, In addition to the spray nozzle that atomizes the jetted absorption liquid by using kinetic energy, liquid that is formed into an umbrella shape centering around the spray nozzle when the absorption liquid is jetted out exclusively from the spray nozzle without using the kinetic energy of exhaust gas. Wet-type flue gas desulfurization device characterized in that a spray nozzle that atomizes the absorbing liquid by the shearing force generated by the growth of the turbulence of the film is installed in the exhaust gas passage 5. The back pressure of a spray nozzle for ejecting the absorbing liquid is set to 0.5 kg / cm ² or less in a region where the absorbing liquid is atomized by utilizing the kinetic energy of exhaust gas, and the gas flow velocity in the vicinity of the spray nozzle is 10 m. / S or more, without utilizing the kinetic energy of the exhaust gas, when the absorbing liquid is ejected from the spray nozzle exclusively, the absorbing liquid is absorbed by the shearing force generated by the growth of the disorder of the liquid film formed in an umbrella shape around the spray nozzle. The wet flue gas desulfurization apparatus according to claim 4, wherein the back pressure of the atomizing spray nozzle is set to 0.5 kg / cm ² or more. 6. When the absorbing liquid is ejected exclusively from the spray nozzle without utilizing the kinetic energy of the exhaust gas, the absorbing liquid is generated by the shearing force generated by the growth of the disorder of the liquid film formed in an umbrella shape around the spray nozzle. A liquid recovery device for recovering the absorption liquid ejected from the atomizing spray nozzle is provided in the exhaust gas flow path, and the absorption liquid recovered from the liquid recovery device is atomized using the kinetic energy of the exhaust gas. 6. A wet flue gas desulfurization apparatus according to claim 4 or 5, further comprising a liquid supply tank for supplying the spray nozzle. 7. The absorption liquid is generated by a shearing force generated by the growth of disorder of a liquid film formed in an umbrella shape around the spray nozzle when the absorption liquid is ejected from the spray nozzle without utilizing the kinetic energy of the exhaust gas. 7. The wet flue gas desulfurization apparatus according to claim 6, wherein a circulation system for circulating the absorption liquid in the absorption liquid tank is provided only to the spray nozzle for atomizing. 8. The wet flue gas desulfurization apparatus according to claim 1, wherein an exhaust gas passage in the absorption tower is formed in a vertical direction. 9. The wet flue gas desulfurization apparatus according to claim 1, wherein the exhaust gas passage in the absorption tower is formed in a direction not vertical. 10. The wet flue gas desulfurization apparatus according to claim 1, wherein the exhaust gas passage in the absorption tower is formed in a vertical direction and a non-vertical direction.