WO2010131327A1

WO2010131327A1 - Equipment for the desulfurization of flue gas with seawater and process for treatment of the seawater used in the desufurization

Info

Publication number: WO2010131327A1
Application number: PCT/JP2009/058780
Authority: WO
Inventors: 知雄秋山; 進沖野; 英次越智
Original assignee: 三菱重工業株式会社
Priority date: 2009-05-11
Filing date: 2009-05-11
Publication date: 2010-11-18
Also published as: KR20110061597A; SA109300664B1; MY170614A; KR101269707B1

Abstract

The first equipment (10-1) for the desulfurization with seawater according to the invention has both a flue gas desulfurization /absorption tower (13) for bringing the sulfur-containing substances contained in flue gas (11) into contact with absorber seawater (12A) (which is part of seawater (12)) and thereby purifying the flue gas, and a dilution/mixing tank (16) which is provided under the flue gas desulfurization/absorption tower (13) integrally therewith and in which seawater (14A) containing sulfur-containing substances (which is generated in the desulfurization/absorption tower (13) by bringing the sulfur -containing substances contained in flue gas (11) into contact with absorber seawater (12A) and thereby desulfurizing the flue gas with the absorber seawater (12A)) is mixed and diluted with diluent seawater (12B) which is fed into the body (15). Further, the equipment (10-1) also has a gas residence section (20A) equipped with both a cover (18) which is provided on the lower end side of the side wall (17) of the flue gas desulfurization /absorption tower (13) along the longer direction of the dilution/mixing tank (16) in such a way that the cover (18) extends over the dilution/mixing tank (16), and a first weir (19) which hangs down from the back side of the cover (18) in such a way that the end of the weir (19) is buried under the water surface in the dilution/mixing tank (16).

Description

Seawater flue gas desulfurization apparatus and processing method of desulfurized seawater

The present invention relates to a seawater flue gas desulfurization apparatus, a seawater flue gas desulfurization system, and a method for treating desulfurized seawater, which desulfurize sulfur such as oxide sulfur in an exhaust gas from an industrial combustion facility using seawater.

In recent years, thermal power plants equipped with seawater flue gas desulfurization equipment have been increasing. From the viewpoints such as power plants that require a large amount of cooling water, they are often built in locations facing the sea, and that the desulfurization equipment costs can be kept lower than the lime-gypsum method. Seawater desulfurization, in which desulfurization is performed using as an absorbing liquid, has attracted attention.

In a normal thermal power plant, since a large amount of seawater is used as cooling water in a boiler condenser, a part of the seawater effluent discharged from the condenser and heated is supplied to a seawater flue gas desulfurization device. The SO _{2 in} the exhaust gas is removed by using it as an absorbing liquid for desulfurization of seawater flue gas.

An example of a flow diagram of a thermal power generation system provided with a seawater flue gas desulfurization device using conventional seawater is shown in FIG. As shown in FIG. 9, a thermal power generation system 100 using a conventional seawater flue gas desulfurization apparatus uses a preheated air 101 to burn with a burner (not shown), and is heat-exchanged by the boiler 102 and discharged. A dust collector 104 that removes soot and dust in the exhaust gas 103, and sulfur-absorbing seawater 106 containing a high concentration of sulfur produced by desulfurizing and desulfurizing sulfur in the exhaust gas 103 using seawater 105. And a seawater flue gas desulfurization apparatus 107A for performing a water quality recovery process. The seawater flue gas desulfurization apparatus 107A has a high concentration of a flue gas desulfurization absorption tower 108 that collects SO ₂ in the exhaust gas 103 as sulfurous acid (H ₂ SO ₃ ), and a high concentration of sulfur content discharged from the flue gas desulfurization absorption tower 108. And an oxidation tank 109 that performs a water quality recovery process of the sulfur-absorbing seawater 106 contained in the water (Patent Documents 1 and 2).

Exhaust gas 103 generated by combustion in the boiler 102 is fed to a flue gas denitration device (not shown) and denitrated, and then fed to a dust collector 104 to remove the dust in the exhaust gas 103. Then, the exhaust gas 103 removed by the dust collector 104 is supplied into the exhaust gas desulfurization device 108 of the seawater exhaust gas desulfurization device 107A by the induction fan 110.

In the flue gas desulfurization absorption tower 108, the sulfur content in the exhaust gas 103 is desulfurized using a part of the seawater 105A for absorption out of the seawater 105 pumped up from the sea 111. That is, the exhaust gas 103 produced by burning fossil fuel contains a sulfur content that is sulfur oxide (SO _x ) in the form of SO ₂ or the like. In seawater desulfurization, an absorption seawater 105A of the flue gas desulfurization absorber tower 108 is supplied via the exhaust gas 103 and seawater supply line 112 by gas-liquid contact, to absorb SO ₂ in the flue gas 103 in the absorber seawater 105A . The purified gas 113 desulfurized by the flue gas desulfurization absorption tower 108 passes through the purified gas discharge passage 114 and is released into the atmosphere from the chimney 115. In the flue gas desulfurization absorption tower 108, the reaction shown in the following formula occurs by the contact between the seawater 105A and the exhaust gas 103.
SO ₂ (g) + H ₂ O → H ₂ SO ₃ (l) → HSO ₃ ⁻ + H ⁺ (I)

The gas-liquid contact between the seawater 105A and the exhaust gas 103 absorbs SO ₂ in the exhaust gas 103 to generate H ₂ SO ₃ , which dissociates in the seawater 105A, so that the seawater 105A and the exhaust gas 103 are brought into gas-liquid contact. In the later seawater 105A, the concentration of HSO ₃ ⁻ increases, and H ⁺ is released, so that the pH decreases. The pH of the sulfur-absorbing seawater 106 produced by absorbing a large amount of sulfur is about 3-6.

The sulfur-absorbing seawater 106 discharged from the flue gas desulfurization absorption tower 108 needs to have its pH raised to 6.0 or higher before being released or reused into the sea 111. Therefore, the sulfur-absorbing seawater 106 containing sulfur is mixed with part of the seawater 105 supplied by the secondary seawater supply line 116 in the oxidation tank 109 as dilution seawater 105B, and at the same time from the oxidizing air blower 117. Air 118 is supplied into the oxidation tank 109 through the nozzle 120 of the diffuser pipe 119 and is brought into gas-liquid contact with the sulfur-absorbing seawater to cause a reaction as shown in the following formula. By mixing and diluting the seawater 105 as dilution seawater 105C, the sulfurous acid used as the COD source is reduced, the dissolved oxygen concentration and pH are raised to restore the water quality, and the water quality restored seawater 122 is released to the sea 111. .
O ₂ (g) → O ₂ (l) (II)
HSO ₃ ⁻ + 1 / 2O ₂ (l) → + SO ₄ ²⁻ + H ⁺ (III)
HCO ₃ ⁻ + H ⁺ → H ₂ CO ₃ (l) → CO ₂ (g) ↑ + H ₂ O (IV)
CO ₃ ^2- + 2H ⁺ → H ₂ CO ₃ (l) → CO ₂ (g) ↑ + H ₂ O (V)

As described above, in the thermal power generation system 100 using the conventional seawater flue gas desulfurization apparatus, the sulfur-absorbing seawater 106 is discharged from a condenser (not shown) in order to prevent the diffusion of SO ₂ and improve the pH in the oxidation tank 109. The mixture is diluted with the seawater 105 and the oxidation tank 109 and oxidized and aerated in the oxidation tank 109 to oxidize and detoxify the sulfurous acid, increase the dissolved oxygen concentration, decarboxylate, and absorb the sulfur content. The pH of the seawater drainage 122 is discharged so as to satisfy the drainage standard (usually pH 6.0 or higher) (Patent Documents 1 and 2).

Moreover, the other structure of the conventional seawater flue gas desulfurization apparatus is shown in FIG. FIG. 10 is a diagram simply showing another configuration of the seawater flue gas desulfurization apparatus applied to the conventional seawater desulfurization system. As shown in FIG. 10, another conventional seawater flue gas desulfurization apparatus 107B includes a flue gas desulfurization absorption tower 131 for desulfurizing SO ₂ in the exhaust gas 103 to sulfurous acid (H ₂ SO ₃ ), and a flue gas desulfurization absorption tower. 131, a dilution mixing tank 132 for diluting and mixing sulfur-absorbing seawater 106 A containing sulfur with dilution seawater 105 B, and a downstream of the dilution-mixing tank 132, An oxidation tank 133 that performs water quality recovery treatment (Patent Document 3).

In the seawater flue gas desulfurization apparatus 107 B, a part of the seawater 105 A for absorption in the seawater 105 supplied via the seawater supply line 112 in the flue gas desulfurization absorption tower 131 is brought into gas-liquid contact with the exhaust gas 103. Of SO ₂ is absorbed by the absorbing seawater 105A. Then, the sulfur-absorbing seawater 106 A that has absorbed the sulfur in the flue gas desulfurization absorption tower 131 is mixed with the dilution seawater 105 B supplied to the dilution mixing tank 132 provided in the lower part of the flue gas desulfurization absorption tower 131. Then, the sulfur-absorbing seawater 106B mixed and diluted with the dilution seawater 105B is supplied to the oxidation tank 133 provided on the downstream side of the dilution mixing tank 132, and the air 118 is diffused from the oxidation air blower 117. After being supplied through the oxidized air nozzle 120 to recover the water quality, the water is discharged.

JP 2006-055779 A JP 2007-125474 A International Publication No. 2008/077430

However, in the conventional seawater flue gas desulfurization apparatus 107B, bubbles containing a gas having a high SO ₂ concentration enter the dilution seawater 105B in the dilution mixing tank 132 due to entrainment of bubbles by the sulfur-absorbing seawater 106A in the dilution mixing tank 132. When the sulfur-absorbing seawater 106B mixed with the dilution seawater 105B flows into the oxidation tank 133 that is open to the outdoors, the SO ₂ is diffused in the oxidation tank 133 and emits an irritating odor. There is a problem that there is a fear.

Further, like the conventional seawater flue gas desulfurization apparatus 107B, the flue gas desulfurization absorption tower 131 is installed on the upper side of the dilution mixing tank 132 which becomes a drainage channel of a condenser (not shown) through which the seawater 105 used for dilution flows. In an apparatus in which the seawater desulfurization and the oxidation treatment of the used seawater are integrated, the sulfur-absorbing seawater 106A and the seawater 105B supplied to the dilution and mixing tank 132 may not be sufficiently mixed due to a temperature difference between them. There's a problem.

In addition, when the sulfur-absorbing seawater 106A flowing down the flue gas desulfurization absorption tower 131 falls into the diluted seawater channel, bubbles containing SO ₂ are accumulated in the flue gas desulfurization absorption tower 131, and the flue gas desulfurization absorption tower 131 outside. There is a problem that bubbles containing high concentration of SO ₂ flow out.

In view of the above problems, the present invention prevents the SO ₂ recovered in seawater from being diffused when oxidizing seawater used for desulfurization, and is a safe and highly reliable seawater flue gas desulfurization apparatus. It is another object of the present invention to provide a method for treating desulfurized seawater.

A first invention of the present invention for solving the above-mentioned problems is provided integrally with a flue gas desulfurization absorption tower that purifies sulfur content in exhaust gas by contacting with seawater, and under the flue gas desulfurization absorption tower. In the flue gas desulfurization absorption tower, the sulfur content absorption seawater generated by bringing the sulfur content in the exhaust gas into contact with the seawater and desulfurizing the seawater is mixed and diluted with seawater fed into the main body. And a lid portion extending from the bottom side of the side wall of the flue gas desulfurization absorption tower so as to cover the dilution mixing tank, and suspended from the back surface side of the lid section, in the dilution mixing tank The seawater flue gas desulfurization apparatus has a gas retention part including a first weir whose end is buried in the water surface.

According to a second invention, in the first invention, the length L1 from the side wall of the flue gas desulfurization absorption tower to the inner wall of the first weir is any one of the following formulas (1) and (2): It exists in the seawater flue gas desulfurization apparatus characterized by satisfy | filling following formula (3).
For bubble diameter dp in seawater,
d _G1 <τ ₁ U _t (dp) (1)
Cc> C ₀ exp (−6 Kg / dpτ ₁ ) (2)
_{_{τ 1 = L1 / U L ···}} (3)
Where d _G1 is the opening height from the first weir at the outlet of the gas retention section to the bottom of the dilution mixing tank, τ ₁ is the residence time of seawater in the gas retention section, and U _t (dp) is the seawater Is the final rising speed of the bubble group having the bubble diameter dp, Cc is the SO ₂ environmental standard concentration, C ₀ is the SO ₂ concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the gas-liquid of the bubble an overall mass transfer coefficient of the SO ₂ gas at the interface, dp is the bubble diameter, the U _L is the outlet flow rate of the bottom of the dilution mixing tank.

Further, the terminal rising speed of a single bubble in the static fluid can be obtained from the following Stokes equation (4). The larger the bubble, the higher the terminal rising speed.
U _t = g × dp ² × (ρ _L −ρ _G ) / 18 μ (4)
However, g is the gravitational acceleration, dp is the bubble diameter, the [rho _L seawater density, the [rho _G gas density, mu is the viscosity of sea water.

In addition, when the bubble diameter exceeds 1 mm, the bubble shape does not become spherical due to friction with the fluid, and the rising speed of the bubble group differs from the behavior of a single bubble, so it does not exactly match, but the bubble in seawater The diameter is usually about 0.5 to 1.0 mm, rarely exceeding 5.0 mm at most, and the terminal ascending rate in the seawater is 200 to 300 mm / s, with a maximum of 400 mm / s. It is about s.

The third invention is the seawater flue gas desulfurization apparatus according to the first invention, wherein a second weir is provided at the bottom of the dilution mixing tank.

According to a fourth invention, in the third invention, the length L2 from the side wall of the flue gas desulfurization absorption tower to the inner wall of the second weir is any one of the following formulas (5) and (6): It exists in the seawater flue gas desulfurization apparatus characterized by satisfy | filling following formula (7).
D <τ ₂ U _t (dp) (5)
Cc> C ₀ exp (−6 Kg / dpτ ₂ ) (6)
τ ₂ = L2 / (U _L × D / d _G2 ) (7)
However, D is the depth of seawater in the dilution mixing tank, τ ₂ is the retention time of seawater in the gas retention part, and U _t (dp) is the terminal rising speed of the bubbles having the bubble diameter dp in the seawater. Cc is the SO ₂ environmental standard concentration, C ₀ is the SO ₂ concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the overall mass transfer coefficient of SO ₂ gas at the gas-liquid interface of the bubbles , dp is the bubble diameter, U _L is the outlet flow rate of the bottom of the dilution mixing tank, the d _G2 is the height of the liquid surface between the seawater liquid surface and the second weir.

The fifth invention is the seawater flue gas desulfurization apparatus according to the first invention, wherein a third weir is provided inside the gas retention part.

According to a sixth invention, in the fifth invention, the length L3 from the outer wall of the third weir to the inner wall of the first weir is any one of the following formulas (8) and (9) and the following formula: (10) It is in the seawater flue gas desulfurization apparatus characterized by satisfy | filling.
d _G1 <τ ₃ U _t (dp) (8)
Cc> C ₀ exp (−6 Kg / dpτ ₃ ) (9)
τ ₃ = L3 / (U _L × D / MIN (d _G1, d _G2 )) (10)
Where d _G1 is the opening height from the first weir at the outlet of the gas retention section to the bottom of the dilution mixing tank, τ ₃ is the residence time of seawater in the gas retention section, and U _t (dp) is the seawater Is the final rising speed of the bubble group having the bubble diameter dp, Cc is the SO ₂ environmental standard concentration, C ₀ is the SO ₂ concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the gas-liquid of the bubble an overall mass transfer coefficient of the SO ₂ gas at the interface, dp is the bubble diameter, U _L is the outlet flow rate of the bottom of the dilution mixing tank, D is a liquid depth of the sea water dilution mixing unit, d _G2 Is the opening height from the second weir at the outlet of the gas retention section to the bottom of the dilution mixing tank, and MIN (d _G1, d _G2 ) is the minimum value of d _G1, d _G2 .

The seventh invention is characterized in that, in the first invention, the second weir is provided at the bottom of the dilution mixing tank, and the third weir is provided inside the gas retention part. Located in smoke desulfurization equipment.

According to an eighth invention, in the seventh invention, the length L4 from the outer wall of the third weir to the inner wall of the second weir is any one of the following formulas (11) and (12) and the following formula: (13) It is in the seawater flue gas desulfurization apparatus characterized by satisfy | filling.
D <τ ₄ U _t (dp) (11)
Cc> C ₀ exp (−6 Kg / dpτ ₄ ) (12)
τ ₄ = L4 / (U _L × D / MIN (d _G1 , d _G2 , d _G3 )) (13)
However, D is the depth of seawater in the dilution mixing tank, τ ₄ is the retention time of seawater in the gas retention part, and U _t (dp) is the end rising speed of bubbles having a bubble diameter dp in the seawater. Cc is the SO ₂ environmental standard concentration, C ₀ is the SO ₂ concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the overall mass transfer coefficient of SO ₂ gas at the gas-liquid interface of the bubbles , dp is the bubble diameter, U _L is the outlet flow rate of the bottom of the dilution mixing tank, d _G1 is the opening height to the bottom of the dilution mixing tank from the first weir, d _G2 is a sea liquid surface D _G3 is the opening height from the third weir to the bottom of the diluting mixing tank, and MIN (d _G1 , d _G2 , d _G3 ) is: It is the minimum value of d _G1 , d _G2 , and d _G3 .

According to a ninth invention, in any one of the fifth to eighth inventions, the third weir communicates the space between the gas retention part and the seawater and the flue gas desulfurization absorption tower. It exists in the seawater flue gas desulfurization apparatus characterized by having.

A tenth aspect of the invention is the seawater flue gas desulfurization apparatus according to any one of the first to ninth aspects, wherein the seawater is discharged from a condenser.

In an eleventh aspect of the present invention, in any one of the first to tenth aspects, the sulfur component in seawater mixed with the sulfur-absorbing seawater in the dilution / mixing tank is oxidized downstream of the dilution / mixing tank. And a seawater flue gas desulfurization apparatus characterized by having an oxidation tank that decarboxylates and recovers water quality.

The twelfth invention uses a boiler, exhaust gas discharged from the boiler as a heat source for generating steam, a steam turbine that drives a generator using the generated steam, and water condensed in the steam turbine. Any one of the first to eleventh inventions, a condenser that collects and circulates, a flue gas denitration device that denitrates exhaust gas discharged from the boiler, a dust collector that removes soot in the exhaust gas, and A seawater flue gas desulfurization apparatus and a chimney for discharging the purified gas desulfurized by the flue gas desulfurization apparatus to the outside.

The thirteenth invention is to prevent the SO ₂ gas contained in the seawater used for the desulfurization using the seawater flue gas desulfurization apparatus according to any one of the first to eleventh inventions from being diffused to the outside. In the processing method of the desulfurization seawater characterized by these.

According to the present invention, the flue gas desulfurization absorption tower for purifying sulfur in the exhaust gas by contacting with seawater and the flue gas desulfurization absorption tower are integrally provided below the flue gas desulfurization absorption tower, Gas retention provided with a lid having a certain length extending so as to cover the dilution / mixing tank at a connecting portion with the dilution / mixing tank for mixing the sulfur-absorbing seawater with the seawater fed into the main body And has a first weir suspended from the back side of the lid and embedded in the water surface of the dilution mixing tank, so that the sulfur-absorbing seawater is the flue gas desulfurization. Bubbles containing gas having a high SO ₂ concentration in the sulfur-absorbing seawater trapped in the seawater by flowing down from an absorption tower in the gas retention part formed by the lid part and the first weir It is possible to prevent the SO ₂ gas from leaking outside by being diffused into the space.

As a result, when the seawater is oxidized to restore the water quality, the seawater containing SO ₂ flows out to the oxidation tank, and SO ₂ is diffused in the outdoor open type oxidation tank to prevent the emission of irritating odors. Therefore, it is possible to provide a seawater flue gas desulfurization apparatus that is safe and highly reliable.

FIG. 1 is a schematic diagram showing the configuration of a seawater flue gas desulfurization apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic view schematically showing a part of the configuration of the seawater flue gas desulfurization apparatus according to the first embodiment of the present invention. FIG. 3 is a schematic view schematically showing a part of the configuration of a conventional seawater flue gas desulfurization apparatus. FIG. 4 is a schematic view schematically showing a part of the configuration of the seawater flue gas desulfurization apparatus according to the second embodiment of the present invention. FIG. 5 is a schematic view schematically showing a part of the configuration of the seawater flue gas desulfurization apparatus according to the third embodiment of the present invention. FIG. 6 is a partially enlarged view of the configuration of the seawater flue gas desulfurization apparatus according to the third embodiment of the present invention. FIG. 7 is a schematic view schematically showing a part of the configuration of the seawater flue gas desulfurization apparatus according to the fourth embodiment of the present invention. FIG. 8 is a conceptual diagram showing a seawater desulfurization system. FIG. 9 is a diagram illustrating an example of a flow diagram of a thermal power generation system including a seawater flue gas desulfurization device using conventional seawater. FIG. 10 is a diagram simply showing another configuration of the seawater flue gas desulfurization apparatus applied to the conventional seawater desulfurization system.

Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

[First embodiment]
A seawater flue gas desulfurization apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing the configuration of the seawater flue gas desulfurization apparatus according to the first embodiment of the present invention, and FIG. 2 is a simplified diagram of a part of the configuration of the seawater flue gas desulfurization apparatus shown in FIG. FIG.

As shown in FIG. 1, the first seawater flue gas desulfurization apparatus 10-1 according to the present embodiment removes the sulfur content in the exhaust gas 11 by bringing it into contact with a portion of the seawater 12 for absorbing seawater 12 A. A smoke desulfurization absorption tower 13 is provided integrally with the flue gas desulfurization absorption tower 13, and the sulfur content in the exhaust gas 11 is brought into contact with the absorbing sea water 12A in the flue gas desulfurization absorption tower 13 to desulfurize the sea water. The sulfur-absorbing seawater 14A flowing down in the flue gas desulfurization absorption tower 13 produced by the above-mentioned is provided with the dilution seawater 12B fed into the main body 15 and the dilution mixing tank 16 for mixing and diluting, and the flue gas desulfurization absorption tower A lid 18 extending along the longitudinal direction of the dilution / mixing tank 16 so as to cover the dilution / mixing tank 16 on the lower end side of the side wall 17 of the thirteen; The first end 19a is buried in the sea water surface Those having a gas retaining portion 20A that includes a 19.
In the figure, reference numeral 16 a is the bottom of the dilution / mixing tank 16.

In the present embodiment, the seawater 12 is supplied to the flue gas desulfurization absorption tower 13 and used for purification of the exhaust gas 11 as the absorption seawater 12A, and is supplied to the flue gas desulfurization absorption tower 13 for dilution. The seawater used for the dilution is designated as seawater 12B for dilution. The seawater in which the dilution seawater 12B and the sulfur-absorbing seawater 14A flowing down in the flue-gas desulfurization absorption tower 13 are mixed in the flue gas desulfurization absorption tower 13 is referred to as sulfur-absorption seawater 14B.

Absorption seawater 12A used in the flue gas desulfurization absorption tower 13 is a part of the seawater 12 extracted by the pump 24 out of the seawater 12 pumped from the sea 21 to the seawater supply line 23 using the pump 22. Absorption seawater 12A is fed to the flue gas desulfurization absorption tower 13. Moreover, although the seawater 12 uses the seawater pumped directly from the sea 21 by the pump 22, the present invention is not limited to this, and the drainage of the seawater 12 discharged from a condenser (not shown) is used. You may make it use.

In the flue gas desulfurization absorption tower 13, the exhaust gas 11 and the absorbing seawater 12 A are brought into gas-liquid contact to desulfurize the sulfur content in the exhaust gas 11. That is, the exhaust gas 11 and the absorbing seawater 12A are brought into gas-liquid contact in the flue gas desulfurization absorption tower 13 to cause a reaction represented by the following formula, and sulfur contained in the exhaust gas 11 in the form of SO ₂ or the like. Sulfur content such as oxide (SO _x ) is removed using seawater for absorption 12A.
SO ₂ (g) + H ₂ O → H ₂ SO ₃ (l) → HSO ₃ ⁻ + H ⁺ (I)

The seawater desulfurization causes H ₂ SO ₃ generated by gas-liquid contact between the absorption seawater 12A and the exhaust gas 11 to dissociate and release H ⁺ into the absorption seawater 12A. A large amount of sulfur is absorbed by the sulfur-absorbing seawater 14 A flowing down in 13. At this time, the pH of the sulfur-absorbing seawater 14A flowing down in the flue gas desulfurization absorption tower 13 is, for example, about 3. Then, the sulfur-absorbing seawater 14 A flows down in the flue gas desulfurization absorption tower 13 and is stored in a dilution and mixing tank 16 that is integrally provided on the lower side of the flue gas desulfurization absorption tower 13. Further, the purified gas 25 desulfurized in the flue gas desulfurization absorption tower 13 is released into the atmosphere through the purified gas discharge passage 26.

Further, a part of the seawater 12 from the seawater supply line 23 passes through the dilution seawater supply line 27 as dilution seawater 12B and is fed to the dilution mixing tank 16. And in the dilution mixing tank 16, the sulfur content absorption seawater 14A which flows down in the flue gas desulfurization absorption tower 13 is mixed with the seawater 12B for dilution, and is diluted. Seawater in which the sulfur-absorbing seawater 14A flowing down in the flue gas desulfurization absorption tower 13 and the dilution seawater 12B are mixed is defined as sulfur-absorbing seawater 14B. By mixing and diluting the sulfur-absorbing seawater 14A with the seawater 12B, the pH of the sulfur-absorbing seawater 14B in the dilution mixing tank 16 can be raised, and re-emission of SO ₂ can be prevented.

Further, FIG. 2 is a schematic view schematically showing a part of the configuration of the seawater flue gas desulfurization apparatus according to the present embodiment. As shown in FIG. 2, the first seawater flue gas desulfurization apparatus 10-1 according to the present embodiment has a dilution mixing tank 16 on the lower end side of the side wall 17 on the downstream side of the dilution mixing tank of the flue gas desulfurization absorption tower 13. A cover 18 extending so as to cover the cover 18 and a first weir 19 suspended from the back surface side of the cover 18 and having an end 19a buried in the seawater surface on the water surface in the dilution / mixing tank 16 were provided. It has a gas retention part 20A. Then, the first weir 19 hangs down from the gas retention part 20A, and the sulfur-absorbing seawater 14B in which the dilution seawater 12B and the sulfur-absorbing seawater 14A flowing down in the flue gas desulfurization absorption tower 13 are mixed. The part is dammed in the flue gas desulfurization absorption tower 13.

When the sulfur-absorbing seawater 14A flows down from the flue gas desulfurization absorption tower 13, the bubbles 28 containing the gas having a high SO ₂ concentration in the flue gas desulfurization absorption tower 13 are caught in the sulfur-absorption seawater 14B. The bubbles 28 containing SO ₂ gas entrained in the sulfur-absorbing seawater 14B are diffused into the space S1 formed by the lid portion 18 and the first weir 19 of the gas retention portion 20A. For this reason, the SO ₂ gas entrained in the sulfur-absorbing seawater 14B can remain in the space S1 formed by the lid portion 18 and the first weir 19 of the gas retention portion 19B.

FIG. 3 is a schematic view schematically showing a part of the configuration of the conventional seawater flue gas desulfurization apparatus shown in FIG. The conventional seawater flue gas desulfurization apparatus 107B shown in FIG. 3 extends the downstream side wall plate of the dilution and mixing tank of the flue gas desulfurization absorption tower 131 to the sulfur-absorbing seawater 106B of the dilution and mixing tank 132 as it is. The end is buried. Therefore, the conventional seawater flue gas desulfurization apparatus 107B includes a gas having a high SO ₂ concentration entrained in the dilution seawater 105B by entrainment of bubbles by the sulfur-absorbing seawater 106A flowing down in the flue gas desulfurization absorption tower 131. There is a risk that bubbles rise and are diffused out of the flue gas desulfurization absorption tower 131, and SO ₂ gas leaks to the outside.

On the other hand, in the present embodiment, a lid portion 18 extending from the lower end side of the side wall 17 of the flue gas desulfurization absorption tower 13 so as to cover the dilution / mixing tank 16 and a back surface side of the lid portion 18 are suspended. The gas retention part 20A provided with the first weir 19 whose end is buried in the water surface in the dilution mixing tank 16 is provided, and the end 19a of the first weir 19 is buried in the water surface in the dilution mixing tank 16 And partially immersed in the sulfur-absorbing seawater 14B in the main body 15. For this reason, even if the bubbles 28 including the gas having a high SO ₂ concentration are caught in the sulfur-absorbing seawater 14B by the entrainment of the bubbles 28 due to the sulfur-absorbing seawater 14A flowing down from the flue gas desulfurization absorption tower 13, the sulfur content The bubbles 28 containing SO ₂ gas entrained in the absorption seawater 14B can be diffused into the space S1 formed by the lid 18 and the first weir 19 of the gas retention part 20A. As a result, the SO ₂ gas can be retained in the space S1 formed by the lid 18 and the first weir 19 of the gas retention part 19B, and the SO ₂ gas can be prevented from leaking to the outside.

As a result, as will be described later, when the sulfur-absorbing seawater 14B flows into the outdoor open type oxidation tank 29, the bubbles 28 containing SO ₂ gas entrained in the dilution and mixing tank 16 flow, and SO _{2 in the} oxidation tank 29 flows. It can be emitted and prevented from leaking to the outside, and it can be prevented to emit an irritating odor.

In the present embodiment, the length L1 from the side wall 17 of the flue gas desulfurization absorption tower 13 to the inner wall 19b of the first weir 19 is either one of the following formulas (1) and (2) and the following formula: (3) is satisfied.
d _G1 <τ ₁ U _t (dp) (1)
Cc> C ₀ exp (−6 Kg / dpτ ₁ ) (2)
_{_{τ 1 = L1 / U L ···}} (3)
Where d _G1 is the opening height from the first weir at the outlet of the gas retention section to the bottom of the dilution mixing tank, τ ₁ is the residence time of seawater in the gas retention section, and U _t (dp) is the seawater Is the final rising speed of the bubble group having the bubble diameter dp, Cc is the SO ₂ environmental standard concentration, C ₀ is the SO ₂ concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the gas-liquid of the bubble an overall mass transfer coefficient of the SO ₂ gas at the interface, dp is the bubble diameter, the U _L is the outlet flow rate of the bottom of the dilution mixing tank.

Here, the terminal rising speed U _t of a single bubble in the static fluid is obtained from the following Stokes equation (4). The larger the bubble, the higher the terminal rising speed.
U _t = g × dp ² × (ρ _L −ρ _G ) / 18 μ (4)
However, g is the gravitational acceleration, dp is the bubble diameter, the [rho _L seawater density, the [rho _G gas density, mu is the viscosity of sea water.

In addition, when the bubble diameter exceeds 1 mm, the bubble shape does not become spherical due to friction with the fluid, and the rising speed of the bubble group differs from the behavior of a single bubble, so it does not exactly match, but the bubble in seawater The diameter is usually about 0.5 to 1.0 mm, rarely exceeding 5.0 mm at most, and the terminal group rising speed U _t in seawater is 200 to 300 mm / s, which is the maximum. However, it is about 400 mm / s.

By satisfying the above equation as in the present embodiment, among the bubbles 28 containing SO ₂ gas entrained in the sulfur-absorbing seawater 14B, relatively large bubbles having a high levitation speed can be further ensured. The SO ₂ gas can be diffused by diffusing into the space S1 formed by the lid 18 and the first weir 19 of the gas retention part 20A. In addition, among the air bubbles 28 containing sulfur absorbing seawater 14B SO ₂ gas caught in the SO ₂ gas in small relatively small bubbles floating speed can be absorbed into the sulfur absorbing seawater 14B.

For this reason, bubbles 28 containing SO ₂ gas entrained in the dilution and mixing tank 16 flow into the oxidation tank 29 together with the sulfur-absorbing seawater 14B, and SO ₂ is diffused in the oxidation tank 29 to prevent release of an irritating odor. Can do.

As a result, as will be described later, the gas generated when the quality of the sulfur-absorbing seawater 14B is recovered in the oxidation tank 29 can be diffused in the oxidation tank 29 so as to satisfy the SO ₂ environmental standard concentration.

Accordingly, the bubbles 28 containing the high-concentration SO ₂ gas entrained in the dilution / mixing tank 16 are diffused in the oxidation tank 29 installed on the downstream side of the dilution / mixing tank 16, and the SO ₂ gas leaks to the outside. Can be prevented, and a safe and highly reliable seawater desulfurization absorption apparatus can be provided.

Then, after the bubbles 28 in the sulfur-absorbing seawater 14B are diffused in the dilution / mixing tank 16, the sulfur-absorbing seawater 14B is supplied to an oxidation tank 29 provided on the downstream side of the dilution / mixing tank 16. Moreover, in this Embodiment, although the dilution mixing tank 16 and the oxidation tank 29 are comprised by one tank integrally, this invention is not limited to this, The dilution mixing tank 16 and the oxidation tank 29 are comprised. As a separate tank, the dilution mixing tank 16 and the oxidation tank 29 may be connected.

The oxidation tank 29 is provided integrally on the downstream side of the dilution / mixing tank 16, and oxidizes the sulfur content in the sulfur-absorbing seawater 14B and decarboxylates it to restore the water quality. The oxidation tank 29 is provided with an air supply unit 30. The air supply unit 30 includes an oxidizing air blower 32 that supplies air 31, an air diffuser 33 that supplies the air 31, and an oxidized air nozzle 34 that supplies the air 31 to the sulfur-absorbing seawater 14 B in the oxidation tank 29. It consists of In the oxidation tank 29, the air 31 is sent from the oxidation air nozzle 34 to the oxidation tank 29 through the diffuser pipe 33 by the oxidation air blower 32, and the sulfur content comes into contact with the air 31 in the oxidation tank 29 and the following formula (II) Oxygen dissolution, sulfurous acid oxidation reaction, and decarboxylation reaction as shown in (V).
O ₂ (g) → O ₂ (l) (II)
HSO ₃ ⁻ + 1 / 2O ₂ → SO ₄ ²⁻ + H ⁺ (III)
HCO ₃ ⁻ + H ⁺ → CO ₂ (g) + H ₂ O (IV)
CO ₃ ^2- + 2H ⁺ → CO ₂ (g) + H ₂ O (V)

In the oxidation tank 29, the sulfur-absorbing seawater 14B is recovered by the oxidation reaction of bisulfite ions (HSO ₃ ⁻ ) in the sulfur-absorbing seawater 14 and the decarboxylation reaction of bicarbonate ions (HCO ₃ ⁻ ). It becomes the recovery seawater 35.

And the water quality recovery seawater 35 is discharged to the sea 21 as seawater waste liquid through the seawater discharge line 36. As a result, the pH of the water-modified seawater 35 can be raised and the COD can be reduced, and the pH, dissolved oxygen concentration, and COD of the water-quality-recovered seawater 35 can be released to a level at which seawater can be discharged.

Thus, according to the first seawater flue gas desulfurization apparatus 10-1 according to the present embodiment, the flue gas desulfurization absorption tower 13 for purifying the sulfur content in the exhaust gas 11 by contacting with the seawater 12A, the exhaust gas Mixing / diluting with the dilution seawater 12B fed into the main body 15 of the sulfur-absorbing seawater 14A provided integrally with the lower side of the smoke desulfurization absorption tower 13 and desulfurizing the seawater in the flue gas desulfurization absorption tower 13 A dilution mixing tank 16, a lid 18 extending so as to cover the dilution mixing tank 16 on the lower end side of the side wall 17 of the flue gas desulfurization absorption tower 13, and a drooping and mixing from the back side of the lid 18 It has a gas retention part 20A provided with a first weir 19 whose end 19a is buried in the water surface in the tank 16. The first weir 19 hangs down from the back side of the lid 18, and its end 19 a is buried in the water surface in the dilution and mixing tank 16, and a part of the sulfur-absorbing seawater 14 B is contained in the flue gas desulfurization absorption tower 13. I try to stop it. Accordingly, when the sulfur-absorbing seawater 14A flows down from the flue gas desulfurization absorption tower 13, the bubbles 28 containing the gas having a high SO ₂ concentration entrained in the sulfur-absorbing seawater 14B are removed from the lid portion 18 of the gas retaining portion 20A and the first. It is possible to prevent the SO ₂ gas from leaking outside by being diffused into the space S1 formed by the one weir 19.

As a result, when the sulfur-absorbing seawater 14B flowing into the outdoor open type oxidation tank 29 is oxidized to recover the water quality, bubbles 28 containing SO ₂ gas entrained in the dilution mixing tank 16 flow into the oxidation tank 29. A seawater flue gas desulfurization apparatus that can be prevented from being diffused, preventing SO ₂ from leaking to the outside, and preventing an irritating odor from being emitted, can be provided.

Moreover, in this Embodiment, although the seawater flue gas desulfurization apparatus which processes the seawater which used the oxidation tank 29 for seawater desulfurization by the flue gas desulfurization absorption tower 13 was demonstrated, this invention is not limited to this. Absent. The oxidation tank 29 desulfurizes sulfur oxides contained in exhaust gas discharged from, for example, factories in various industries, power plants such as large and medium-sized thermal power plants, large boilers for electric utilities, or general industrial boilers. It can be used for the removal of sulfur content in the sulfur-absorbing seawater 14A produced in the above, and desulfurized seawater.

[Second Embodiment]
Next, a seawater flue gas desulfurization apparatus according to a second embodiment of the present invention will be described with reference to FIG.
Since the configuration of the seawater flue gas desulfurization apparatus is the same as that of the seawater flue gas desulfurization apparatus according to the first embodiment of the present invention, the configuration diagram of the entire seawater flue gas desulfurization apparatus according to the above embodiment is omitted, and the above embodiment is implemented. The same reference numerals are assigned to the same components as those of the seawater flue gas desulfurization apparatus according to the embodiment, and redundant description is omitted.
FIG. 4 is a schematic view schematically showing a part of the configuration of the seawater flue gas desulfurization apparatus according to the present embodiment. As shown in FIG. 4, the second seawater flue gas desulfurization apparatus 10-2 according to the present embodiment is the same as the first seawater flue gas desulfurization apparatus 10- according to the first embodiment shown in FIGS. 1 has a gas retention part 20B in which a second weir 42 is provided at the bottom part 16a of one dilution mixing tank 16.

As in the present embodiment, by providing the second weir 42 at the bottom 16a of the dilution mixing tank 16, the liquid surface between the liquid surface of the sulfur-absorbing seawater 14B and the end 42a of the second weir 42 The height d _G2 is reduced. Therefore, the flow rate of the sulfur-absorbing seawater 14B flowing through the oxidation tank 29 is increased, and the bubbles 28 in the sulfur-absorbing seawater 14B are placed between the liquid surface of the sulfur-absorbing seawater 14B and the end 42a of the second weir 42. Can concentrate. As a result, the bubbles 28 can be diffused into the space S1 formed by the lid 18 and the first weir 19 of the gas retention part 20B.

Thus, dissipate SO ₂ bubbles 28 containing SO ₂ gas caught in diluted mixing tank 16 to flow to the oxidation tank 29, preventing the SO ₂ gas from leaking to the outside, that the emitting irritating odor Can be prevented.

In addition, when the sulfur-absorbing seawater 14A, which is the desulfurized flow down liquid, is mixed with the dilution seawater 12B in the dilution mixing tank 16, the liquid temperature is high because the sulfur-absorbing seawater 14A is in contact with the exhaust gas 11, and the dilution seawater Since the liquid temperature of 12B is low, it is difficult to mix uniformly by simply merging. In the present embodiment, since the second weir 42 is provided at the bottom 16a of the dilution mixing tank 16, the liquid surface between the liquid surface of the sulfur-absorbing seawater 14B and the end 42a of the second weir 42 is provided. The height d _G2 is small, and the flow rate of the sulfur-absorbing seawater 14B flowing through the oxidation tank 29 can be increased. For this reason, mixing with the sulfur content absorption seawater 14A and the seawater 12B for dilution can be accelerated | stimulated.

In the present embodiment, the length L2 in the flow direction of the sulfur-absorbing seawater 14B from the side wall 17 of the flue gas desulfurization absorption tower 13 to the inner wall 42b of the second weir 42 is expressed by the following formula (5), ( 6) and the following expression (7) are satisfied.
D <τ ₂ U _t (dp) (5)
Cc> C ₀ exp (−6 Kg / dpτ ₂ ) (6)
τ ₂ = L2 / (U _L × D / d _G2 ) (7)
However, D is the depth of seawater in the dilution mixing tank, τ ₂ is the retention time of seawater in the gas retention part, and U _t (dp) is the terminal rising speed of the bubbles having the bubble diameter dp in the seawater. Cc is the SO ₂ environmental standard concentration, C ₀ is the SO ₂ concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the overall mass transfer coefficient of SO ₂ gas at the gas-liquid interface of the bubbles , dp is the bubble diameter, U _L is the outlet flow rate of the bottom of the dilution mixing tank, the d _G2 is the height of the liquid surface between the seawater liquid surface and the second weir.

By satisfying the above equation as in the present embodiment, the bubbles 28 containing SO ₂ gas in the sulfur-absorbing seawater 14B are more reliably formed by the gas retention part 20B and the first weir 19. Can be diffused into the space S1 and the SO ₂ gas can be diffused. This prevents bubbles 28 containing SO ₂ gas entrained in the dilution and mixing tank 16 from flowing into the oxidation tank 29 together with the sulfur-absorbing seawater 14B, so that SO ₂ is diffused in the oxidation tank 29 and prevents the emission of irritating odors. Can do.

As a result, as described above, the gas generated when the quality of the sulfur-absorbing seawater 14B is recovered in the oxidation tank 29 can be diffused in the oxidation tank 29 so as to satisfy the SO ₂ environmental standard concentration.

Therefore, according to the second seawater flue gas desulfurization apparatus 10-2 according to the present embodiment, the sulfur content-absorbing seawater flowing into the oxidation tank 29 is provided by providing the second weir 42 at the bottom 16a of the dilution mixing tank 16. The flow rate of 14B is increased, the bubbles 28 are concentrated on the upper surface of the liquid, and the mixing of the sulfur-absorbing seawater 14A and the diluting seawater 12B is promoted in the dilution mixing tank 16, and the bubbles 28 in the sulfur-absorbing seawater 14B are gasified. It can be diffused in the space S 1 formed by the lid portion 18 of the staying portion 20 B and the first weir 19. For this reason, it is possible to prevent bubbles 28 containing SO ₂ gas entrained in the dilution and mixing tank 16 from flowing into the oxidation tank 29 and leaking SO ₂ gas to the outside in the oxidation tank 29, thereby ensuring safety and reliability. A high seawater flue gas desulfurization apparatus can be provided.

[Third embodiment]
Next, a seawater flue gas desulfurization apparatus according to a third embodiment of the present invention will be described with reference to FIGS.
Since the configuration of the seawater flue gas desulfurization apparatus is the same as that of the seawater flue gas desulfurization apparatus according to the first embodiment of the present invention, the configuration diagram of the entire seawater flue gas desulfurization apparatus according to the above embodiment is omitted, and the above embodiment The same reference numerals are assigned to the same components as those of the seawater flue gas desulfurization apparatus according to the embodiment, and redundant description is omitted.
FIG. 5 is a schematic view schematically showing a part of the configuration of the seawater flue gas desulfurization apparatus according to the present embodiment, and FIG. 6 is a partially enlarged view of the configuration of the seawater flue gas desulfurization apparatus according to the present embodiment. It is.

Here, in the tower of the flue gas desulfurization absorption tower 13 which is a seawater desulfurization absorption tower, a large amount of bubbles is absorbed because the sulfur-absorbing seawater 14A which is a large amount of seawater flowing down falls on the dilution mixing tank 16 which is a dilute seawater channel. Has been confirmed to occur. It has been confirmed that the amount of foam generated depends on the quality of seawater and the concentration of SO ₂ gas in the exhaust gas 11. When a large amount of foam is generated, the dilution mixing tank inside the flue gas desulfurization absorption tower 13 is used. 16 is covered with foam and may flow out to the outside due to the flow of the sulfur-absorbing seawater 14B.

As shown in FIG. 5, the third seawater flue gas desulfurization apparatus 10-3 according to the present embodiment has a gas retention part 20C in which a third weir 43 is provided inside the gas retention part 20C. The third weir 43 is suspended from the back surface side of the lid 18, the end 43 a is buried in the water surface in the dilution and mixing tank 16, and the seawater 12 C is mixed with the seawater 12 B and the sulfur-absorbing seawater 14. This part is dammed in the flue gas desulfurization absorption tower 13 to prevent the outflow of bubbles generated inside the flue gas desulfurization absorption tower 13 which is an absorption tower.

By immersing the end 43a of the third weir 43 suspended from the back side of the lid 18 in the water surface in the dilution mixing tank 16, the partial flow of the sulfur-absorbing seawater 14B is blocked to dilute. In the mixing tank 16, the mixing of the sulfur-absorbing seawater 14 A and the dilution seawater 12 B is promoted, and in the space S 2 formed by the lid 18, the first dam 19, and the third dam 43 of the gas retention part 20 C. The bubbles 28 can be diffused to prevent the SO ₂ gas from leaking outside, and the outflow of bubbles generated inside the flue gas desulfurization absorption tower 13 can be prevented. Thereby, it is possible to prevent the bubbles 28 containing the SO ₂ gas entrained in the diluting and mixing tank 16 from flowing into the oxidation tank 29 and leaking the SO ₂ gas to the outside, thereby preventing an irritating odor from being emitted.

Further, in the present embodiment, as shown in FIGS. 5 and 6, a space formed in the third dam 43 by the lid portion 18 of the gas retaining portion 20 C, the first dam 19, and the third dam 43. A vent hole 44 is provided to communicate S2 with the flue gas desulfurization absorption tower 13. Therefore, the SO ₂ gas filled in the space S2 formed by the lid 18 of the gas retention part 20B, the first dam 19 and the third dam 43 can be diffused to the flue gas desulfurization absorption tower 13 side. .

In the present embodiment, the height d _G3 between the end portion 43 a of the third weir 43 and the bottom surface 16 a of the dilution mixing tank 16 is equal to the end portion 19 a of the first weir 19 and the dilution mixing tank 16. Although the height is the same as the height d _G1 between the bottom surface 16a, the height d _G1 is not limited to this and may be different.

In the present embodiment, the length L3 in the flow direction of the seawater 12C from the outer wall 43b of the third weir 43 to the inner wall 41a of the first weir 19 is any of the following formulas (8) and (9). On the other hand, the following equation (10) is satisfied.
d _G1 <τ ₃ U _t (dp) (8)
Cc> C ₀ exp (−6 Kg / dpτ ₃ ) (9)
τ ₃ = L3 / (U _L × D / MIN (d _G1, d _G2 )) (10)
Where d _G1 is the opening height from the first weir at the outlet of the gas retention section to the bottom of the dilution mixing tank, τ ₃ is the residence time of seawater in the gas retention section, and U _t (dp) is the seawater Is the final rising speed of the bubble group having the bubble diameter dp, Cc is the SO ₂ environmental standard concentration, C ₀ is the SO ₂ concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the gas-liquid of the bubble an overall mass transfer coefficient of the SO ₂ gas at the interface, dp is the bubble diameter, U _L is the outlet flow rate of the bottom of the dilution mixing tank, D is a liquid depth of the sea water dilution mixing unit, d _G2 Is the opening height from the second weir at the outlet of the gas retention section to the bottom of the dilution mixing tank, and MIN (d _G1, d _G2 ) is the minimum value of d _G1, d _G2 .

By satisfying the above equation as in the present embodiment, the air bubbles 28 containing SO ₂ gas in the sulfur-absorbing seawater 14B can be more reliably removed from the lid portion 18 and the first weir 19 of the gas retention portion 20C. And the third weir 43 can be diffused into the space S2. This prevents bubbles 28 containing SO ₂ gas entrained in the dilution mixing tank 16 from flowing into the oxidation tank 29 together with the sulfur-absorbing seawater 14B, so that SO ₂ is diffused in the oxidation tank 29 and is prevented from leaking to the outside. It can prevent giving off odor.

Therefore, according to the third seawater flue gas desulfurization apparatus 10-3 according to the present embodiment, the third weir 43 is provided inside the gas retention part 20C in the flow direction of the sulfur-absorbing seawater 14B, and the dilution mixing tank The height of the liquid level between the bottom 16 a of the 16 and the third weir 43 is reduced. Thereby, in the dilution mixing tank 16, mixing with the sulfur content absorption seawater 14A and the dilution seawater 12B is accelerated | stimulated, and it forms with the cover part 18, the 1st dam 19, and the 3rd dam 43 of the gas retention part 20C. The bubbles 28 can be diffused into the space S2 to prevent the SO ₂ gas from leaking to the outside, and the outflow of bubbles generated inside the flue gas desulfurization absorption tower 13 can be prevented. For this reason, it is possible to prevent the bubbles 28 entrained in the diluting / mixing tank 16 from flowing into the oxidation tank 29 and leaking SO ₂ gas to the outside in the oxidation tank 29, and safe and highly reliable seawater. A flue gas desulfurization apparatus can be provided.

[Fourth embodiment]
Next, a seawater flue gas desulfurization apparatus according to a fourth embodiment of the present invention will be described with reference to FIG.
Since the configuration of the seawater flue gas desulfurization apparatus is the same as that of the seawater flue gas desulfurization apparatus according to the first embodiment of the present invention, the configuration diagram of the entire seawater flue gas desulfurization apparatus according to the above embodiment is omitted, and the above embodiment is implemented. The same reference numerals are assigned to the same components as those of the seawater flue gas desulfurization apparatus according to the embodiment, and redundant description is omitted.
FIG. 7 is a schematic view schematically showing a part of the configuration of the seawater flue gas desulfurization apparatus according to the present embodiment. As shown in FIG. 7, the seawater flue gas desulfurization apparatus 10-4 according to the fourth embodiment according to the present embodiment is the first according to the first embodiment according to the present invention shown in FIGS. Seawater flue gas desulfurization apparatus 10-1, a second seawater flue gas desulfurization apparatus 10-2 according to the second embodiment of the present invention shown in FIG. 4, and a third implementation according to the present invention shown in FIG. And a third seawater flue gas desulfurization apparatus 10-3 according to the above embodiment.

That is, as shown in FIG. 7, the fourth seawater flue gas desulfurization apparatus 10-4 according to the present embodiment performs dilution so as to cover the dilution mixing tank 16 on the lower end side of the side wall 17 of the flue gas desulfurization absorption tower 13. A first weir 19 that hangs down from the back side of the lid 18 that extends along the longitudinal direction of the mixing tank 16 and whose end 19 a is buried in the water surface in the dilution mixing tank 16; A second weir 42 on the bottom 16a and a third weir 43 hanging from the back side of the lid 18 inside the lid 18 and having its end 43a buried in the water surface in the dilution mixing tank 16 are provided. The first dam 19 and the third dam 43 hang down from the lid 18 and have a sulfur-absorbing seawater 14B in which the dilution seawater 12B and the sulfur-absorbing seawater 14A are mixed. Is partially dammed in the flue gas desulfurization tank 13.

The first weir 19 suspended from the back surface side of the lid portion 18 of the gas retaining portion 20D was provided, the second weir 42 was provided at the bottom portion 16a of the dilution mixing tank 16, and the first weir 19 was suspended from the back surface side of the lid portion 18. By providing the third weir 43, as described above, while promoting the mixing of the sulfur-absorbing seawater 14A and the diluting seawater 12B, the flow rate of the sulfur-absorbing seawater 14B flowing toward the oxidation tank 29 is increased, The bubbles 28 containing SO ₂ gas in the sulfur-absorbing seawater 14B in the dilution mixing tank 16 can be diffused into the space S2 formed by the first weir 19 and the third weir 43 of the gas retention part 20D. .

In the present embodiment, the length L4 from the outer wall 43b of the third weir 43 to the inner wall 42b of the second weir 42 is either one of the following formulas (11) and (12) and the following formula ( 13) is satisfied.
D <τ ₄ U _t (dp) (11)
Cc> C ₀ exp (−6 Kg / dpτ ₄ ) (12)
τ ₄ = L4 / (U _L × D / MIN (d _G1 , d _G2 , d _G3 )) (13)
However, D is the depth of seawater in the dilution mixing tank, τ ₄ is the residence time of seawater in the gas residence part, and U _t (dp) is the terminal rising speed of the bubble group having the bubble diameter dp in the seawater. Cc is the SO ₂ environmental standard concentration, C ₀ is the SO ₂ concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the overall mass transfer coefficient of SO ₂ gas at the gas-liquid interface of the bubbles , dp is the bubble diameter, U _L is the outlet flow rate of the bottom of the dilution mixing tank, d _G1 is the opening height to the bottom of the dilution mixing tank from the first weir, d _G2 is a sea liquid surface D _G3 is the opening height from the third weir to the bottom of the diluting mixing tank, and MIN (d _G1 , d _G2 , d _G3 ) is: It is the minimum value of d _G1 , d _G2 , and d _G3 .

By satisfying the above equation as in the present embodiment, the bubbles 28 containing SO ₂ gas entrained in the sulfur-absorbing seawater 14B can be more reliably secured to the first weir 19 of the gas retention part 20D. And the third weir 43 can be diffused into the space S2. This prevents bubbles 28 containing SO ₂ gas entrained in the dilution and mixing tank 16 from flowing into the oxidation tank 29 together with the sulfur-absorbing seawater 14B, so that SO ₂ is not diffused to the outside in the oxidation tank 29 and leaks. It can prevent giving off odor.

Therefore, according to the fourth seawater flue gas desulfurization apparatus 10-4 according to the present embodiment, the mixing of the sulfur-absorbing seawater 14A and the diluting seawater 12B in the dilution-mixing tank 16 is further promoted, and the sulfur-absorption is absorbed. The bubbles 28 in the seawater 14B can be diffused into the space S2 formed by the first weir 19 and the third weir 43 of the gas retention part 20D. Thus, more reliably prevented from leaking SO ₂ gas to the outside oxidation tank 29 SO ₂ to flow to the outside in the oxidation tank 29 by air bubbles 28 flows containing SO ₂ gas caught in diluted mixing tank 16 It is possible to provide a seawater flue gas desulfurization apparatus that is safe and reliable.

[Fifth embodiment]
Next, a seawater desulfurization system according to a fifth embodiment using the seawater flue gas desulfurization apparatus of the present invention will be described with reference to FIG.
FIG. 8 is a conceptual diagram showing a seawater desulfurization system. Since the configuration of the seawater flue gas desulfurization apparatus is the same as that of the seawater flue gas desulfurization apparatus according to the first to fifth embodiments of the present invention, the description thereof is omitted here.

As shown in FIG. 8, the seawater desulfurization system 50 according to the present embodiment is discharged from the boiler 53, which is burned by a burner (not shown) using air 52 preheated by an air preheater (AH) 51. The exhaust gas 54 is used as a heat source for generating steam, the steam turbine 57 that drives the generator 56 using the generated steam 55, and the condenser 58 that collects and circulates the water 58 condensed by the steam turbine 57. 59, a flue gas denitration device 60 that denitrates the exhaust gas 54 discharged from the boiler 53, a dust collector 61 that removes soot and dust in the exhaust gas 54 discharged from the boiler 53, and the sulfur content in the exhaust gas 54 is converted into seawater The flue gas desulfurization absorption tower 71 to be removed by using 62, and the seawater exhaust gas for performing water quality recovery processing of the sulfur content absorption seawater 63A containing a high concentration of sulfur content generated in the flue gas desulfurization absorption tower 71 A desulfurization apparatus 64, in which the exhaust gas 54 becomes the chimney 66. for discharging purified gas 65 which is desulfurized outside with flue gas desulfurization absorber tower 71.

The air 52 supplied from the outside is supplied to the air preheater 51 by the pushing fan 67 and preheated. Fuel (not shown) and air 52 preheated by the air preheater 51 are supplied to the burner, and the fuel is burned by the boiler 53 to generate steam 55 for driving the steam turbine 57. Further, fuel (not shown) used in the present embodiment is supplied from, for example, an oil tank.

The exhaust gas 54 generated by combustion in the boiler 53 is sent to the flue gas denitration device 60. At this time, the exhaust gas 54 exchanges heat with the water 58 discharged from the condenser 59 and is used as a heat source for generating steam 55, and the generated steam 55 drives the generator 56 of the steam turbine 57. Then, the water 58 condensed by the steam turbine 57 is returned to the boiler 53 again and circulated.

Then, the exhaust gas 54 discharged from the boiler 53 and guided to the flue gas denitration device 60 is denitrated in the flue gas denitration device 60, exchanges heat with the air 52 by the air preheater 51, and then is sent to the dust collector 61. The dust in the exhaust gas 54 is removed.

Then, the exhaust gas 54 that has been dust-removed by the dust collector 61 is supplied to the seawater flue gas desulfurization device 64. As the seawater flue gas desulfurization apparatus 64, the seawater flue gas desulfurization apparatus according to the present invention is used. That is, the seawater flue gas desulfurization device 64 is provided with a flue gas desulfurization absorption tower 71 for purifying the sulfur content in the exhaust gas 54 by bringing it into contact with a part of the seawater 62A for absorption of the seawater 62, and under the flue gas desulfurization absorption tower 71 The sulfur-absorbing seawater 63A generated by bringing the sulfur content in the exhaust gas 54 into contact with the absorbing seawater 62A and desulfurizing in the flue gas desulfurization absorption tower 71 is fed into the main body 72. It has a dilution seawater 62B and a dilution mixing tank 73 for mixing and diluting, and extends along the longitudinal direction of the dilution mixing tank 73 so as to cover the dilution mixing tank 73 on the lower end side of the side wall 74 of the flue gas desulfurization absorption tower 71. A gas retaining portion 77 having a lid portion 75 provided and a first weir 76 which is suspended from the back surface side of the lid portion 75 and whose end portion is buried in the water surface in the dilution and mixing tank 73. It is. Further, an oxidation tank 78 is provided integrally with the dilution mixing tank 73 on the downstream side of the dilution mixing tank 73 to oxidize and decarboxylate the sulfur content in the sulfur-absorbing seawater 63B to restore the water quality. The sulfur-absorbing seawater 63B is seawater in which the dilution seawater 62B and the sulfur-absorbing seawater 62A flowing down in the flue gas desulfurization absorption tower 71 are mixed. The oxidation tank 78 is provided with an oxidation air blower 80 for supplying air 79, a diffuser pipe 81 for supplying the air 79, and an oxidation air nozzle 82 for supplying the air 79 to the seawater 62C in the oxidation tank 78. ing.

Specifically, the exhaust gas 54 is supplied into the flue gas desulfurization absorption tower 71 by the induction fan 83. At this time, the exhaust gas 54 is heat-exchanged with the purified gas 65 desulfurized and discharged by the flue gas desulfurization absorption tower 71 by the heat exchanger 84, and then supplied into the flue gas desulfurization absorption tower 71.

In the flue gas desulfurization absorption tower 71, seawater desulfurization is performed by using a part of the seawater 62 pumped up from the sea 85 as the sulfur content contained in the exhaust gas 54 as the absorption seawater 62A. The exhaust gas 54 produced by burning fossil fuel contains a sulfur content that is sulfur oxide (SO _x ) in the form of SO ₂ or the like. And absorbing seawater 62A of the flue gas desulfurization absorber tower 71 is supplied via the exhaust 54 and the seawater supply line 86 by gas-liquid contact, to absorb SO ₂ in the flue gas 54 to absorption seawater 62A, seawater desulfurization Is going. The seawater 62 pumped up from the sea 85 by the pump 87 is heat-exchanged by the condenser 59, and then a part of the seawater 62A for absorption of the seawater 62 that is the drainage of the condenser 59 is exhausted by the pump 88. It is fed to the absorption tower 71. Further, the purified gas 65 desulfurized by the flue gas desulfurization absorption tower 71 is released from the chimney 66 into the atmosphere.

The sulfur-absorbing seawater 63A is collected in a dilution and mixing tank 73 that is integrally provided below the flue gas desulfurization absorption tower 71. Further, a part of the seawater 62 is supplied as dilution seawater 62B to the dilution mixing tank 73 via the dilution seawater supply line 89. Thus, the sulfur content-absorbing seawater 63A can be diluted with the dilution seawater 62B, and the pH of the sulfur-content-absorbing seawater 63B can be increased.

Further, a lid 75 in which a gas retention part 77 is extended along the longitudinal direction of the dilution / mixing tank 73 so as to cover the dilution / mixing tank 73 on the lower end side of the side wall 74 of the flue gas desulfurization absorption tower 71, and this lid 75 has a gas retention part 77 provided with a first weir 76 that hangs down from the back surface side of 75 and whose end is buried in the water surface in the dilution and mixing tank 73. For this reason, the bubbles 90 containing the high-concentration SO ₂ gas entrained in the bottom 73a of the dilution mixing tank 73 are diffused into the space S11 in the gas retention part 77, and remain in this space S11, and the SO ₂ gas. Can be prevented from leaking into the downstream oxidation tank 77.

Moreover, in this Embodiment, although demonstrated using the 1st seawater flue gas desulfurization apparatus which concerns on the above-mentioned this Embodiment as the seawater flue gas desulfurization apparatus 64, it is not limited to this, The above-mentioned The second to fourth seawater flue gas desulfurization apparatuses according to the present embodiment may be used.

Then, air 79 is supplied from the oxidizing air blower 80 through the diffuser pipe 81 into the oxidizing tank 78 from the oxidizing air nozzle 82 to oxidize the bisulfite ions in the sulfur-absorbing seawater 63B and from the bicarbonate ions. Carbon dioxide is desorbed. As a result, the water content of the sulfur-absorbing seawater 63B is recovered and becomes the water-modified seawater 91.

After that, the water-modified seawater 91 that has been subjected to the water quality recovery process in the oxidation tank 78 is discharged into the sea 85 as seawater drainage liquid via the seawater discharge line 92.

Thus, according to the seawater desulfurization system 50 according to the present embodiment, the sulfur-absorbing seawater 63 generated by the seawater desulfurization in the oxidation tank 77 is recovered in the dilution mixing tank 73 and mixed and diluted with the dilution seawater 62B. At the same time, bubbles 90 containing high-concentration SO ₂ gas generated by the flow of the sulfur-absorbing seawater 63A into the dilution seawater 62B at the bottom of the dilution mixing tank 73 are generated in the downstream open oxidation tank 77. Since it can be diffused and SO ₂ can be prevented from leaking to the outside, a safe and highly reliable seawater desulfurization system can be provided.

As described above, the seawater flue gas desulfurization apparatus according to the present invention is externally used when SO ₂ entrained in seawater is oxidized when sulfur-absorbed seawater generated by seawater desulfurization is mixed with seawater for dilution. Since it can be prevented from being diffused, it is suitable for use in a seawater flue gas desulfurization apparatus that adjusts so that seawater used for seawater desulfurization can be released to the ocean.

10-1 to 10-4 First seawater flue gas desulfurization device to fourth seawater flue gas desulfurization device 11

Exhaust gas

12, 12A, 62, 62A Seawater (seawater for absorption)
12B, 62B

Dilution sea water

13, 71 Flue gas

desulfurization absorption tower

14A, 14B Sulfur content

absorption sea water

15, 72

Main body

16, 73 Dilution mixing tank

16a Bottom portion

17, 74

Side wall

18, 75 Lid portion

18a End portion

19, 76 First 19a End portion 19b Inner wall 20A to 20D, 77

Gas retention portion

21, 85

Sea

22, 24

Pump

23, 86 Seawater supply line 25 Purified gas 26 Purified

gas discharge passage

27, 88 Dilution

seawater supply line

28, 90

Bubbles

29 , 78 Oxidation tank 30

Air supply unit

31, 79

Air

32, 80

Oxidizing air blower

33, 81

Air diffuser pipe

34, 82

Oxidized air nozzle

35, 91 Water quality modified

seawater

36, 92 Seawater discharge line 42 Second weir

42a End portion

42b Inner wall 43 Third weir

43a End portion

43b Outer wall 44 Vent hole 50 Seawater desulfurization system 51 Air preheating (AH)
52, 78 Air 53 Boiler 54 Exhaust gas 55 Steam 56 Generator 57 Steam turbine 58 Water 59 Condenser 60 Flue gas denitration device 61 Dust collector 63 Sulfur content absorption seawater 64 Seawater flue gas desulfurization device 65 Purified gas 66 Chimney 67 Push-in fan 83 Induction fan 84

Heat exchanger

87, 88 Pump S1-S2, S11 Space

Claims

A flue gas desulfurization absorption tower for purifying sulfur in the exhaust gas by contacting with seawater;
Provided integrally below the flue gas desulfurization absorption tower, the sulfur content absorption seawater generated by bringing the sulfur content in the exhaust gas into contact with the seawater and desulfurizing the seawater in the flue gas desulfurization absorption tower With seawater fed to the tank and a dilution / mixing tank for mixing / dilution,
A lid portion extending from the lower side of the side wall of the flue gas desulfurization absorption tower so as to cover the dilution mixing tank, and suspended from the back side of the lid section, and an end portion of the water surface in the dilution mixing tank A seawater flue gas desulfurization apparatus comprising a gas retention portion including a first weir to be buried.
In claim 1,
The length L1 from the side wall of the flue gas desulfurization absorption tower to the inner wall of the first weir satisfies either one of the following formulas (1) and (2) and the following formula (3). Seawater flue gas desulfurization equipment.
For bubble diameter dp in seawater,
d G1 <τ 1 U t (dp) (1)
Cc> C 0 exp (−6 Kg / dpτ 1 ) (2)
τ 1 = L1 / U L ··· (3)
Where d G1 is the opening height from the first weir at the outlet of the gas retention section to the bottom of the dilution mixing tank, τ 1 is the residence time of seawater in the gas retention section, and U t (dp) is the seawater Is the final rising speed of the bubble group having the bubble diameter dp, Cc is the SO 2 environmental standard concentration, C 0 is the SO 2 concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the gas-liquid of the bubble an overall mass transfer coefficient of the SO 2 gas at the interface, dp is the bubble diameter, the U L is the outlet flow rate of the bottom of the dilution mixing tank.
In claim 1,
A seawater flue gas desulfurization apparatus comprising a second weir at the bottom of the dilution mixing tank.
In claim 3,
The length L2 from the side wall of the flue gas desulfurization absorption tower to the inner wall of the second weir satisfies any one of the following formulas (4) and (5) and the following formula (6). Seawater flue gas desulfurization equipment.
D <τ 2 U t (dp) (4)
Cc> C 0 exp (−6 Kg / dpτ 2 ) (5)
τ 2 = L2 / (U L × D / d G2 ) (6)
However, D is the depth of seawater in the dilution mixing tank, τ 2 is the retention time of seawater in the gas retention part, and U t (dp) is the terminal rising speed of the bubbles having the bubble diameter dp in the seawater. Cc is the SO 2 environmental standard concentration, C 0 is the SO 2 concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the overall mass transfer coefficient of SO 2 gas at the gas-liquid interface of the bubbles , dp is the bubble diameter, U L is the outlet flow rate of the bottom of the dilution mixing tank, the d G2 is the height of the liquid surface between the seawater liquid surface and the second weir.
In claim 1,
A seawater flue gas desulfurization apparatus, wherein a third weir is provided inside the gas retention part.
In claim 5,
The length L3 from the outer wall of the third weir to the inner wall of the first weir satisfies any one of the following formulas (7) and (8) and the following formula (9). Flue gas desulfurization equipment.
d G1 <τ 3 U t (dp) (7)
Cc> C 0 exp (−6 Kg / dpτ 3 ) (8)
τ 3 = L3 / (U L × D / MIN (d G1, d G2 )) (9)
Where d G1 is the opening height from the first weir at the outlet of the gas retention section to the bottom of the dilution mixing tank, τ 3 is the residence time of seawater in the gas retention section, and U t (dp) is the seawater Is the final rising speed of the bubble group having the bubble diameter dp, Cc is the SO 2 environmental standard concentration, C 0 is the SO 2 concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the gas-liquid of the bubble an overall mass transfer coefficient of the SO 2 gas at the interface, dp is the bubble diameter, U L is the outlet flow rate of the bottom of the dilution mixing tank, D is a liquid depth of the sea water dilution mixing unit, d G2 Is the opening height from the second weir at the outlet of the gas retention section to the bottom of the dilution mixing tank, and MIN (d G1, d G2 ) is the minimum value of d G1, d G2 .
In claim 1,
While providing a second weir at the bottom of the dilution mixing tank,
A seawater flue gas desulfurization apparatus, wherein a third weir is provided inside the gas retention part.
In claim 7,
The length L4 from the outer wall of the third weir to the inner wall of the second weir satisfies any one of the following formulas (10) and (11) and the following formula (12). Flue gas desulfurization equipment.
D <τ 4 U t (dp) (10)
Cc> C 0 exp (−6 Kg / dpτ 4 ) (11)
τ 4 = L4 / (U L × D / MIN (d G1 , d G2 , d G3 )) (12)
However, D is the depth of seawater in the dilution mixing tank, τ 4 is the residence time of seawater in the gas residence part, and U t (dp) is the terminal rising speed of the bubble group having the bubble diameter dp in the seawater. Cc is the SO 2 environmental standard concentration, C 0 is the SO 2 concentration at the inlet of the flue gas desulfurization absorption tower, and Kg is the overall mass transfer coefficient of SO 2 gas at the gas-liquid interface of the bubbles , dp is the bubble diameter, U L is the outlet flow rate of the bottom of the dilution mixing tank, d G1 is the opening height to the bottom of the dilution mixing tank from the first weir, d G2 is a sea liquid surface D G3 is the opening height from the third weir to the bottom of the diluting mixing tank, and MIN (d G1 , d G2 , d G3 ) is: It is the minimum value of d G1 , d G2 , and d G3 .
In any one of claims 5 to 8,
The seawater flue gas desulfurization apparatus, wherein the third weir has a vent hole communicating the space between the gas retention part and the seawater and the flue gas desulfurization absorption tower.
In any one of Claims 1 thru | or 9,
A seawater flue gas desulfurization apparatus, wherein the seawater is drained from a condenser.
In any one of Claims 1 thru | or 10,
Provided in the downstream of the dilution mixing tank,
A seawater flue gas desulfurization apparatus comprising an oxidation tank that oxidizes and decarboxylates sulfur content in seawater mixed with the sulfur-absorbing seawater in the dilution and mixing tank and restores water quality.
With a boiler,
Using the exhaust gas discharged from the boiler as a heat source for generating steam, and a steam turbine for driving a generator using the generated steam;
A condenser for collecting and circulating the water condensed in the steam turbine;
A flue gas denitration device for denitrating exhaust gas discharged from the boiler;
A dust collector for removing the dust in the exhaust gas;
Seawater flue gas desulfurization device according to any one of claims 1 to 11,
A seawater desulfurization system comprising a chimney for discharging the purified gas desulfurized by the flue gas desulfurization apparatus to the outside.
A desulfurized seawater characterized by preventing SO 2 gas contained in seawater used for desulfurization using the seawater flue gas desulfurization apparatus according to any one of claims 1 to 11 from being released to the outside. Processing method.