TWI488682B - Seawater desulfurization system and power generation system - Google Patents

Description

Seawater flue gas desulfurization system and power generation system

The present invention relates to a seawater flue gas desulfurization system and a power generation system for oxidizing sulfur-absorbing seawater, and the sulfur-absorbing component seawater is produced by desulfurization of sulfur components contained in exhaust gas using seawater.

In a power generation facility that uses coal or crude oil as a fuel, a combustion component (hereinafter referred to as "exhaust gas") discharged from a boiler contains a sulfur component such as sulfur oxide (SOx) by burning a fossil fuel such as coal. Therefore, the exhaust gas is subjected to desulfurization treatment to remove sulfur oxides (SOx) such as sulfur dioxide (SO ₂ ) contained in the exhaust gas, and then is discharged to the atmosphere. As such a desulfurization treatment method, there are a lime gypsum method, a spray dryer method, a seawater method, and the like.

Power plants and the like are often built in places facing the sea due to the large amount of cooling water required. Therefore, from the viewpoint of suppressing the operation cost required for the desulfurization treatment, it is proposed to use a seawater flue gas desulfurization apparatus which uses seawater as an absorption liquid for absorbing sulfur oxides in exhaust gas to desulfurize seawater.

The seawater flue gas desulfurization device supplies seawater and boiler exhaust gas to the inside of a desulfurization tower (absorption tower) in which a cylindrical shape or an angular shape such as a substantially cylinder is longitudinally placed, so that seawater is subjected to gas-liquid contact as an absorption liquid. Remove SOx. The desulfurized seawater (the sulfur-absorbing component seawater) used as an absorbent in the desulfurization tower is supplied to the oxidation tank. The sulfur-absorbing component seawater flowing in the oxidation tank is diluted by mixing with seawater not used for desulfurization. In addition, the sulphur component seawater is subjected to decarboxylation (aeration) by fine bubbles flowing out from an aeration device (air distribution device) provided on the bottom surface of the oxidation tank (see, for example, Patent Document 1). Thereby, the sulfur-absorbing seawater is subjected to aeration treatment of SO ₃ and CO ₂ , and is discharged after satisfying the environmental standard.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-125474

The oxidation tank is usually a long water tank (Seawater Oxidation Treatment System) (SOTS) with a width of 20 m to 40 m and a length of 100 m to 200 m. It requires a wide area. In the oxidation tank, oxygen is supplied from the air distributing means provided at the bottom of the oxidation tank to the substantially entire surface of the bottom of the oxidation tank in the state of air.

The oxidation tank used in the prior art supplies oxygen to the seawater of the sulfur-absorbing component flowing in the oxidation tank from the entire surface of the bottom of the oxidation tank, and the power cost required for the operation of the oxidation tank is high. Further, there is also supplied above the sulfur component absorbed in seawater oxidation of SO ₃ and of CO ₂ are necessary for the aeration of oxygen as oxygen properties, and oxygen is supplied than needed, the absorption of sulfur component to perform the seawater efficiently No Oxidation of SO ₃ and aeration of CO ₂ .

Therefore, there is a demand for a seawater flue gas desulfurization system that efficiently treats sulfur-absorbing seawater and reduces the size of the oxidation tank.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a seawater flue gas desulfurization system and a power generation system that efficiently perform treatment of absorbing a sulfur component seawater and reduce the size of the oxidation tank.

A first invention of the present invention for solving the above problems is a seawater flue gas desulfurization system, comprising: a flue gas desulfurization absorption tower that cleans the exhaust gas by bringing gas and liquid gas into contact with seawater; , which is disposed after the above-mentioned exhaust gas desulfurization absorption tower a side, comprising: an air supply means for supplying air to the seawater containing the sulfur component containing the sulfur component; and performing the water quality recovery process of the sulfur-absorbing component seawater; and a seawater supply line for supplying the seawater to the exhaust gas desulfurization absorption tower; An air branch line that supplies a portion of the air supplied to the oxidation tank to the bottom of the tower of the flue gas desulfurization absorber.

According to a second aspect of the invention, there is provided a seawater flue gas desulfurization system according to the first aspect of the invention, comprising: a dilute seawater supply line branched from the seawater supply line; and a part of the seawater is supplied as dilute seawater to the flue gas desulfurization The bottom of the tower of the absorption tower.

According to a third aspect of the invention, the seawater flue gas desulfurization system according to the first aspect of the invention is characterized in that the SO ₂ absorption amount is 3 mmol/l or less with respect to the total amount of the seawater supplied to the flue gas desulfurization absorption tower.

According to a fourth aspect of the invention, the seawater flue gas desulfurization system according to the first aspect of the invention is characterized in that the temperature of the sulfur-absorbing component seawater is 5° C. or higher and 55° C. or lower.

According to a fifth aspect of the invention, the seawater flue gas desulfurization system according to the first aspect of the invention is characterized in that the seawater has a pH of 5.5 or more.

According to a sixth aspect of the invention, there is provided a seawater flue gas desulfurization system according to the first aspect of the invention, comprising: an SO ₂ concentration meter for measuring an inlet SO of the exhaust gas at an inlet and an outlet of the exhaust gas of the exhaust gas desulfurization absorption tower; _a concentration and an outlet SO ₂ concentration; a seawater circulation line that circulates the sulfur-absorbing component seawater in the exhaust gas desulfurization absorption tower on the seawater supply line; and a flow meter disposed on the seawater circulation line, and is determined from a flow rate of the sulfur-absorbing component seawater extracted by the flue gas desulfurization absorption tower; calculating a desulfurization rate in the flue gas desulfurization absorption tower based on an inlet SO ₂ concentration of the exhaust gas and an outlet SO ₂ concentration, and adjusting the dilution through the dilution The supply amount of seawater supplied to the oxidation tank by the seawater supply line.

A seventh aspect of the invention is a power generation system, comprising: a boiler; a steam turbine that uses exhaust gas discharged from the boiler as a heat source for steam generation, and uses the generated steam to drive a generator; a flue gas desulfurization system; a condenser that recovers and circulates water condensed in the steam turbine; and a flue gas denitration device Denitration of the exhaust gas discharged from the boiler; and a dust collecting device that removes coal dust in the exhaust gas.

According to the present invention, the treatment of absorbing the sulfur component seawater can be efficiently performed, and the size of the oxidation tank can be reduced.

10‧‧‧Seawater flue gas desulfurization system

11‧‧‧Exhaust flue gas desulfurization absorption tower

11a‧‧‧Absorption tower slot

12‧‧‧oxidation tank

14‧‧‧Sulphur-absorbing seawater

21‧‧‧ seawater

22‧‧‧Sea

21a‧‧‧absorbing seawater

21b, 21c‧‧‧diluted seawater

22a~22e‧‧‧ pump

25, 61‧‧‧ exhaust

26‧‧‧ spray nozzle

28‧‧‧ Purified gas

29‧‧‧ Air

32a, 32b‧‧‧SO ₂ concentration meter

33‧‧‧ Flowmeter

34‧‧‧Control device

41‧‧‧Aeration device (air distribution device)

42‧‧‧Oxidation air blower

43‧‧‧Distribution tube

44‧‧‧Oxidizing air nozzle

45‧‧‧Water quality restores seawater

50‧‧‧Power generation system

51‧‧‧Boiler

52‧‧‧Vapor turbine

53‧‧‧Condenser

54‧‧‧Exhaust smoke denitration device

55‧‧‧dust collection device

56‧‧‧fuel

57‧‧‧Air preheater (AH)

58‧‧‧ Air

59‧‧‧Injecting fan

60‧‧‧Vapor

62‧‧‧ water

63‧‧‧Generator

65‧‧‧Exhaust fan

66‧‧‧ heat exchanger

67‧‧‧ chimney

L11‧‧‧Seawater supply line

L12‧‧‧Air branch line

L13, L14, L19‧‧‧ diluted seawater supply line

L15‧‧‧ Purified gas exhaust passage

L16‧‧‧Seawater circulation line

L17‧‧‧Sulphur-absorbing seawater discharge line

L18‧‧‧Seawater discharge line

Fig. 1 is a schematic view showing the configuration of a seawater flue gas desulfurization system according to a first embodiment of the present invention.

Fig. 2 is a schematic view showing the configuration of a power generation system according to a second embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings. Further, the present invention is not limited by the following examples. Further, among the constituent elements in the following embodiments, those who can easily assume, substantially the same, and the so-called equal range are included. Further, the constituent elements disclosed in the following examples can be appropriately combined.

[Example 1]

The seawater flue gas desulfurization system of the first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic view showing the configuration of a seawater flue gas desulfurization system according to a first embodiment of the present invention. As shown in Fig. 1, the seawater flue gas desulfurization system 10 of the present embodiment has a flue gas desulfurization absorption tower 11, an oxidation tank 12, a seawater supply line L11, and an air branch line L12.

The seawater 21 is pumped from the sea 22 to the seawater supply line L11 by the pump 22a, and one part of the seawater 21 is taken as the absorbing seawater 21a, and is supplied to the flue gas desulfurization absorption tower 11 via the seawater supply line L11 by the pump 22b. One part of the seawater 21 is sent to the oxidation tank 12 as the diluted seawater 21b via the diluted seawater supply line L13, and a part of the diluted seawater 21b is supplied to the exhaust gas desulfurization absorption tower 11 via the diluted seawater supply line L14 as the diluted seawater 21c. The dilution seawater 21b and 21c flowing in the diluted seawater supply lines L13 and L14 are adjusted by the pumps 22c and 22d.

In the seawater 21, seawater directly immersed in the sea 22 by the pump 22a is used. However, the present embodiment is not limited thereto, and liquid discharging of the seawater 21 discharged from a condenser (not shown) may be used.

The flue gas desulfurization absorption tower 11 is a tower for purifying the exhaust gas 25 by bringing the exhaust gas 25 into gas-liquid contact with the absorbing seawater 21a. In the flue gas desulfurization absorption tower 11, the absorbing seawater 21a is ejected upward in a liquid column by the spray nozzle 26, and the exhaust gas 25 is brought into gas-liquid contact with the absorbing seawater 21a supplied through the seawater supply line L11, and the exhaust gas 25 is discharged. Desulfurization of the sulfur component. In the present embodiment, the spray nozzle 26 is a spray nozzle that is ejected in a liquid column shape upward. However, the spray nozzle 26 is not limited thereto, and may be sprayed downward in a shower shape.

In the present specification, the sulfur component is a sulfur concentration (mass ppm or mass ppb) in which the concentration of all the sulfur compounds contained in the hydrocarbon oil is converted into a sulfur atom. Specific examples thereof include SO ₂ and SO _{3 .} Such as SOx or sulfite ions (SO ₃ ^- ) and the like.

In other words, in the exhaust gas desulfurization absorption tower 11, the exhaust gas 25 is brought into gas-liquid contact with the absorbing seawater 21a, and a reaction represented by the following formula (I) is generated, and sulfur such as SOx contained in the form of SO ₂ or the like in the exhaust gas 25 is generated. The component is absorbed by the absorbing seawater 21a, and the sulphur component in the exhaust gas 25 is removed using the absorbing seawater 21a.

SO ₂ (g)+H ₂ O → H ₂ SO ₃ (l) → HSO ₃ ^- +H ⁺ (I)

By desulfurizing the seawater, the H ₂ SO ₃ generated by the contact of the seawater 21a with the gas of the exhaust gas 25 is dissociated, and the hydrogen ions (H ⁺ ) are released in the seawater 21a, so that the pH value is lowered, and the sulfur component seawater 14 is absorbed. The sulfur component is contained in a high concentration. In this case, the pH of the sulfur-absorbing seawater 14 is, for example, about 3 to 6. Further, the sulfur-absorbing component seawater 14 which absorbs the sulfur component in the flue gas desulfurization absorption tower 11 is accumulated in the bottom of the tower of the flue gas desulfurization absorption tower 11.

Further, the desulfurized purge gas 28 in the flue gas desulfurization absorption tower 11 is discharged to the atmosphere via the purge gas discharge passage L15.

The seawater flue gas desulfurization system 10 of the present embodiment has an air branch line L12 that supplies a portion of the air 29 supplied to the oxidation tank 12 to the bottom of the tower of the flue gas desulfurization absorber tower 11. The air 29 drawn through the air branch line L12 is supplied to the bottom of the flue gas desulfurization absorption tower 11 The portion (absorption column tank) 11a can increase the amount of dissolved oxygen in the sulfur-absorbing seawater 14 in the flue gas desulfurization absorption tower 11. Therefore, in the oxidation tank 12 disposed on the flow side after the exhaust gas desulfurization absorption tower 11, the treatment of absorbing the sulfur component seawater 14 can be efficiently performed, and the air required for the water quality recovery treatment of the sulfur-absorbing seawater 14 can be shortened. 29 blowing distance. Therefore, by shortening the blowing distance of the air 29 in the oxidation tank 12, the flow direction of the absorbing sulfur component seawater 14, that is, the distance in the longitudinal direction of the oxidizing tank 12 can be shortened, so that the size of the oxidizing tank 12 can be reduced.

The air 29 drawn through the air branch line L12 is supplied to the exhaust gas desulfurization absorption tower 11 by the pump 22e. Moreover, the method of supplying the air 29 to the oxidation tank 12 via the air branch line L12 is not limited to the pump 22e, and the air 29 may be formed in the vicinity of the connection portion of the air branch line L12 connected to the oxidation tank 12 as a flow hole shape. It is supplied into the oxidation tank 12.

The seawater flue gas desulfurization system 10 of the present embodiment has a diluted seawater supply line L14 branched from the diluted seawater supply line L13, and supplies a portion of the diluted seawater 21b supplied to the oxidation tank 12 as the diluted seawater 21c to the flue gas desulfurization. The bottom of the tower of the absorption tower 11. Usually, the pH value in the flue gas desulfurization absorption tower 11 is low, so that the sulfur component such as sulfite ions dissolved in the sulfur-absorbing seawater 14 is not oxidized, so that the diluted seawater 21c is directly supplied to the flue gas desulfurization. The absorption tower tank 11a of the absorption tower 11 can raise the pH of the sulfur-absorbing component seawater 14 and promote oxidation of sulfur components such as sulfite ions dissolved in the sulfur-absorbing component seawater 14 accumulated in the absorption tower tank 11a. Further, by supplying the diluted seawater 21c to the absorption tower tank 11a of the exhaust gas desulfurization absorption tower 11, and diluting and absorbing the sulfur component seawater 14, it is possible to absorb the sulfur component by absorbing the sulfur component when the sulfur component seawater 14 is dropped. Oxygen is taken into the seawater 14 to obtain an effect of promoting oxidation of a sulfur component such as sulfite ions dissolved in the sulfur-absorbing seawater 14. Therefore, by supplying the diluted seawater 21c to the absorption tower tank 11a of the exhaust gas desulfurization absorption tower 11, the flue gas desulfurization absorption tower 11 is compared with the case where the diluted seawater 21c is not supplied to the exhaust gas desulfurization absorption tower 11. The oxidation inside is increased by, for example, 20% to 100%, thereby promoting oxidation in the exhaust gas desulfurization absorption tower 11, and the length of the oxidation tank 12 disposed on the flow side after the exhaust gas desulfurization absorption tower 11 can be shortened. Thereby, the size of the oxidation tank 12 can be reduced.

The amount of SO ₂ absorption is preferably the total amount (ΔToS (SO ₂ absorption amount / sea water total amount)) of the absorbing seawater 21a and the diluted seawater 21b supplied to the flue gas desulfurization absorption tower 11 via the seawater supply lines L11 and L13. 3 mmol/l or less, more preferably 2 mmol/l or less, further preferably 1 mmol/l or less. When the ΔToS is 3 mmol/l or less, the pH of the sulfur-absorbing seawater 14 is 4.0 or more, and an effect of promoting oxidation of a sulfur component such as sulfite ion dissolved in the sulfur-absorbing seawater 14 can be obtained. When ΔToS is 2 mmol/l or less, the effect of promoting oxidation of the sulfur component becomes high, and if ΔToS is 1 mmol/l or less, the effect is further increased.

The temperature of the seawater is preferably 5 ° C or more and 55 ° C or less, more preferably 15 ° C or more, and still more preferably 30 ° C or more. When the temperature of the seawater is 5° C. or more, the effect of increasing the oxidation rate by increasing the temperature can be obtained. When the temperature of the seawater is 15° C. or more, the oxidation rate is further increased, so that oxidation can be further obtained. The effect of increasing the speed is such that when the temperature of the seawater is 30 ° C or more, a further higher effect can be obtained.

The pH of the sulfur-absorbing seawater 14 is preferably 4.0 or more and 8.3 or less, more preferably 5.5 or more. When the pH value of the sulfur-absorbing seawater 14 is 4.0 or more, an effect of promoting oxidation of a sulfur component such as sulfite ions dissolved in the sulfur-absorbing seawater 14 can be obtained, and the pH of the sulfur-absorbing seawater 14 is 5.5 or more. A further higher effect can be obtained in the case.

On the inlet side and the outlet side of the exhaust gas 25 of the exhaust gas desulfurization absorber 11, an SO ₂ concentration meter 32a, 32b for measuring the inlet SO ₂ concentration and the outlet SO ₂ concentration of the exhaust gas 25 is provided. Further, the flue gas desulfurization absorption tower 11 is provided with a seawater circulation line L16 that circulates the sulfur-absorbing component seawater 14 in the flue gas desulfurization absorption tower 11 on the seawater supply line L11. On the seawater circulation line L16, a flow meter 33 for measuring the flow rate of the sulfur-absorbing component seawater 14 extracted from the flue gas desulfurization absorption tower 11 is provided. The measurement results measured by the SO ₂ concentration meters 32a and 32b and the flow meter 33 are transmitted to the control device 34. Further, in the present embodiment, the seawater circulation line L16 is provided, but the present invention is not limited thereto, and may not be provided.

The control device 34 calculates the desulfurization rate in the flue gas desulfurization absorption tower 11 based on the inlet SO ₂ concentration and the outlet SO ₂ concentration of the exhaust gas 25 measured by the SO ₂ concentration meters 32a and 32b, and the flow meter 33 measures the exhaust gas. The circulating flow rate of the sulfur-absorbing component seawater 14 circulated in the desulfurization absorption tower 11. The desulfurization rate of the exhaust gas 25 is adjusted by the ratio of the outlet SO ₂ concentration in the exhaust gas 25 supplied to the exhaust gas desulfurization absorption tower 11 to the inlet SO ₂ concentration (outlet SO ₂ concentration / inlet SO ₂ concentration) and the like.

The control device 34 adjusts the supply amount of the absorbing seawater 21a supplied to the flue gas desulfurization absorption tower 11 via the seawater supply line L11 and the diluted seawater 21c supplied to the oxidation tank 12, and supplies it to the flue gas desulfurization absorption tower via the air supply line L12. The supply of air 29 of 11. Thereby, the power required to supply the seawater 21a and the diluted seawater 21c by the pumps 22b and 22d in the exhaust gas desulfurization absorption tower 11 can be realized, and the air is supplied to the bottom portion 11a of the exhaust gas desulfurization absorption tower 11 by the pump 22e. The power is reduced.

Therefore, by blowing the air 29 to the bottom of the tower of the flue gas desulfurization absorption tower 11, the amount of dissolved oxygen in the sulfur-absorbing seawater 14 can be increased in the flue gas desulfurization absorption tower 11, thereby reducing the oxidation tank of the downstream flow. The air blowing distance of 12 can shorten the length direction of the oxidation tank 12, so that the size of the oxidation tank 12 can be reduced.

In this way, the sulfur-absorbing component seawater 14 accumulated in the bottom of the tower of the exhaust gas desulfurization absorption tower 11 is sent to the oxidation tank 12 via the sulfur-absorbing component seawater discharge line L17.

In addition, the sulfur-absorbing component seawater discharge line L17 is connected to the diluted seawater supply line L14, and the sulfur-absorbing component seawater 14 in the sulfur-absorbing seawater discharge line L17 and the absorption seawater 21b may be mixed and diluted. By mixing and diluting the sulfur-absorbing seawater 14 and the absorption seawater 21b, the pH of the sulfur-absorbing component seawater 14 in the sulfur-absorbing seawater discharge line L17 can be increased to prevent the SO ₂ gas from being diffused again. In addition, by preventing SO _{2 from} diffusing in the sulfur-absorbing seawater discharge line L17 and leaking to the outside, it is possible to prevent the discharge of irritating odor.

Further, a dilution mixing tank for diluting and mixing the sulfur-absorbing seawater 14 and the diluted seawater 21b may be provided on the sulfur-absorbing seawater discharge line L17. By mixing and diluting the sulfur-absorbing component seawater 14 with the diluted seawater 21b, the pH of the sulfur-absorbing component seawater 14 in the dilution mixing tank can be increased to prevent re-diffusion of the SO ₂ gas. Further, by preventing the SO _{2 from} diffusing in the dilution mixing tank and leaking to the outside, it is possible to prevent the discharge of the irritating odor.

Further, the sulfur-absorbing seawater 14 is sent to the oxidation tank 12 provided on the flow side after the exhaust gas desulfurization absorption tower 11. The oxidation tank 12 is provided on the flow side after the exhaust gas desulfurization absorption tower 11, and performs a tank for absorbing the water quality recovery treatment of the sulfur component seawater 14. The oxidation tank 12 has a tank (air distribution device) 41 that supplies air 29 to the sulfur-absorbing component diluted seawater 14 as an air supply means.

The aeration device 41 is installed in the oxidation tank 12 and supplies the air 29 to the sulfur-absorbing seawater 14 . In the present embodiment, the aeration device 41 includes an oxidizing air blower 42 that supplies air 29, a diffusing pipe 43 that delivers air 29, and an oxidizing air nozzle 44 that absorbs sulfur-containing seawater in the oxidizing tank 12. 14 supplies air 29. By the oxidizing air blower 42, the outside air 29 is sent from the oxidizing air nozzle 44 to the oxidizing tank 12 via the diffusing pipe 43, and the oxygen of the following formula (II) is dissolved. The sulfur component absorbed in the sulfur component seawater 14 in the oxidation tank 12 is brought into contact with the air 29 to generate an oxidation reaction of bisulfite ions (HSO ₃ ^- ) of the following formulas (III) to (V), and a bicarbonate ion. The decarboxylation reaction of (HCO ₃ ^- ), the sulfur-absorbing seawater 14 is restored by water quality, and the water quality is restored to seawater 45. Further, the number of the oxidizing air nozzles 44 is not particularly limited, and is appropriately set depending on the size of the inside of the oxidation tank 12.

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)

Thereby, the pH value of the sulfur-absorbing component seawater 14 can be raised and the COD (Chemical Oxygen Demand) can be lowered, and the water quality can be restored to the pH value of the seawater 45, the dissolved oxygen concentration, and the COD can be set as the dischargeable seawater. Discharged at the level. Further, even when the water in the sulfur-absorbing component seawater 14 is recovered in the oxidation tank 12, gas is generated, and the generated gas can be diffused into the oxidation tank 12 so as to satisfy the SO ₂ environment reference concentration. The water quality recovery seawater 45 is discharged to the sea 22 via the seawater discharge line L18.

The seawater flue gas desulfurization system 10 of the present embodiment can increase the sulfur absorption component in the flue gas desulfurization absorption tower 11 by supplying the dilute seawater 21b and the air 29 to the absorption tower tank 11a of the flue gas desulfurization absorption tower 11. Since the amount of dissolved oxygen in the seawater 14 can reduce the air blowing distance in the oxidation tank 12, the length direction of the oxidation tank 12 can be shortened, so that the size of the oxidation tank 12 can be reduced.

An example of the relationship between the supply ratio of air and the supply ratio of diluted seawater and the length of the oxidation tank is shown in Table 1. In addition, in the table 1, the bottom of the absorption tower shows the ratio of the supply amount of the air 29 and the diluted seawater 21c supplied to the bottom of the tower (absorption tower tank) 11a of the exhaust gas desulfurization absorption tower 11, and the oxidation tank is a ratio. The ratio of the supply amount of the air 29 and the diluted seawater 21b supplied to the oxidation tank 12 is shown.

As shown in Table 1, by supplying a portion of the air 29 supplied to the oxidation tank 12 to the absorption tower tank 11a of the flue gas desulfurization absorption tower 11, it can be shortened as compared with the case where only the air 29 is supplied to the oxidation tank 12 The length of the oxidation tank 12 (refer to Test Example 1 to Test Example 8, Comparative Examples 1 and 2).

Further, when a part of the air 29 supplied to the oxidation tank 12 is supplied to the bottom portion 11a of the exhaust gas desulfurization absorption tower 11, even if only the air 29 is supplied to the oxidation tank 12 The amount of supply to the absorption tower tank 11a of the flue gas desulfurization absorption tower 11 and the air 29 of the oxidation tank 12 can be reduced, and the length of the oxidation tank 12 can be shortened (refer to Test Examples 4, 7, and 8, Comparative Examples 1 and 2). .

In addition, the diluted seawater 21c supplied to the absorption tower tank 11a of the exhaust gas desulfurization absorption tower 11 and the diluted seawater 21b supplied to the oxidation tank 12 are equalized, even if the supply to the exhaust gas desulfurization absorption tower 11 is reduced. The amount of air in the bottom portion 11a of the tower can also shorten the length of the oxidation tank 12 to substantially the same extent as the supply of air 29 to the bottom portion 11a of the exhaust gas desulfurization absorption tower 11 and the oxidation tank 12, and can be reduced. The effect of the size of the oxidation tank 12 (see Test Examples 1 to 6).

Further, when the amount of the air 29 supplied to the absorption tower tank 11a of the flue gas desulfurization absorption tower 11 and the oxidation tank 12 is equal, the dilution of the tower bottom portion 11a supplied to the flue gas desulfurization absorption tower 11 is alleviated. The total amount of the seawater 21c and the diluted seawater 21b supplied to the oxidation tank 12 can also shorten the length of the oxidation tank 12 as compared with the case where only the air 29 and the diluted seawater 21b are supplied to the oxidation tank 12, and the oxidation tank can be reduced. Effect of size of 12 (refer to Test Examples 5 and 6, and Comparative Example 1).

Therefore, by partially supplying a portion of the air 29 supplied to the oxidation tank 12 to the absorption tower tank 11a of the exhaust gas desulfurization absorption tower 11, the dissolution of the sulfur-absorbing seawater 14 can be improved in the exhaust gas desulfurization absorption tower 11. Oxygen content. Thereby, the blowing distance of the air 29 in the oxidation tank 12 can be reduced, and the longitudinal direction of the oxidation tank 12 can be shortened, so that the size of the oxidation tank 12 can be reduced.

Thus, the seawater flue gas desulfurization system 10 of the present embodiment supplies the air 29 to the tower bottom portion 11a of the flue gas desulfurization absorption tower 11 by supplying a portion of the air 29 supplied to the oxidation tank 12, and supplies it to the oxidation tank. A part of the dilution seawater 21b is supplied to the bottom portion 11a of the exhaust gas desulfurization absorption tower 11, and the air blowing distance in the oxidation tank 12 can be reduced, and the length direction of the oxidation tank 12 can be shortened, so that oxidation can be reduced. The size of the slot 12. Further, since the power required to supply the air 29 to the oxidation tank 12 can be reduced, the sulfur-absorbing seawater 14 flowing through the open-type oxidation tank 12 can be efficiently oxidized to perform water quality recovery. complex.

Therefore, according to the seawater flue gas desulfurization system 10 of the present embodiment, the sulfur-absorbing component seawater 14 discharged from the flue gas desulfurization absorption tower 11 can be provided in the oxidation tank 12, and the sulfur-absorbing seawater 14 can be efficiently treated. A seawater flue gas desulfurization system that performs water quality recovery treatment and achieves a reduction in the size of the oxidation tank 12 and is highly reliable.

Further, in the present embodiment, the seawater flue gas desulfurization system for performing the treatment of the sulfur-absorbing component seawater 14 produced by the seawater desulfurization using the seawater 21a in the flue gas desulfurization absorption tower 11 has been described, but the present invention has been described. It is not limited to this. The seawater flue gas desulfurization system can be applied to waste gas discharged from power plants such as factories in various industries, large-scale and medium-sized thermal power plants, large-scale boilers used in electric power enterprises, general industrial boilers, iron-making plants, refineries, etc. The seawater flue gas desulfurization device for seawater desulfurization of the sulfur oxides contained therein.

Further, in the present embodiment, the flue gas desulfurization absorption tower 11 and the oxidation tank 12 are independent of the respective tanks, and the flue gas desulfurization absorption tower 11 and the oxidation tank 12 are connected by the sulfur absorption component seawater discharge line L17. However, the present embodiment is not limited thereto, and the exhaust gas desulfurization absorption tower 11 and the oxidation tank 12 may be integrally formed as one groove.

[Embodiment 2]

The power generation system of the second embodiment of the present invention will be described with reference to the drawings. The seawater flue gas desulfurization system of the first embodiment is used for the seawater flue gas desulfurization system applied to the power generation system of the present embodiment. The same members as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted.

Fig. 2 is a schematic view showing the configuration of a power generation system according to a second embodiment of the present invention. As shown in FIG. 2, the power generation system 50 of the present embodiment includes a boiler 51, a steam turbine 52, a condenser 53, a smoke exhausting and denitrating device 54, a dust collecting device 55, and a seawater flue gas desulfurization system 10. Further, in the present embodiment, as described above, the sulphur-absorbing component seawater 14 refers to seawater that has been used in the seawater flue gas desulfurization system 10 to absorb sulfur components such as SO ₂ .

The boiler 51 is a fuel 56 and an air preheater supplied from an oil tank or a coal grinder. (AH, Air Heater) 57 preheated air 58 is injected and combusted from a burner (not shown). The air 58 supplied from the outside is sent to the air preheater 57 for preheating by being pressed into the fan 59. The fuel 56 and the air 58 preheated by the air preheater 57 are supplied to the burner, and the fuel 56 is burned in the boiler 51. Thereby, a vapor 60 for driving the steam turbine 52 is generated.

The exhaust gas 61 generated by the combustion in the boiler 51 is sent to the exhaust gas denitration device 54. Further, the exhaust gas 61 exchanges heat with the water 62 discharged from the condenser 53 to serve as a heat source for generating the vapor 60. The steam turbine 52 uses the generated steam 60 to drive the generator 63. Further, the condenser 53 recovers the water 62 condensed in the steam turbine 52, and returns it to the boiler 51 again to circulate it.

The exhaust gas 61 discharged from the boiler 51 is denitrated in the exhaust gas denitration device 54 and exchanged heat with the air 58 by the air preheater 57, and then sent to the dust collecting device 55 to remove the coal dust in the exhaust gas 61. Then, the exhaust gas 61 dedusted by the dust collecting device 55 is supplied to the exhaust gas desulfurization absorption tower 11 by the suction fan 65. At this time, the exhaust gas 61 is supplied to the heat exchanger 66, and is subjected to heat exchange with the purge gas 28 desulfurized and discharged through the flue gas desulfurization absorption tower 11, and then supplied to the flue gas desulfurization absorption tower 11. Further, the exhaust gas 61 may be directly supplied to the exhaust gas desulfurization absorption tower 11 without being exchanged with the purge gas 28 in the heat exchanger 66.

Further, the heat exchanger 66 includes a heat recovery unit and a reheater, and the heat medium circulates between the heat recovery unit and the reheater. The heat recovery device is disposed between the extraction fan 65 and the exhaust gas desulfurization absorption tower 11, and exchanges heat between the exhaust gas 61 discharged from the boiler 51 and the heat medium. The reheater is disposed on the flow side after the flue gas desulfurization absorption tower 11, and exchanges heat between the purge gas 28 discharged from the flue gas desulfurization absorption tower 11 and the heat medium, and reheats the purge gas 28.

The seawater flue gas desulfurization system 10 is the seawater flue gas desulfurization device of the above first embodiment. That is, the seawater flue gas desulfurization system 10 includes the flue gas desulfurization absorption tower 11, the oxidation tank 12, the seawater supply line L11, and the air branch line L12.

In the seawater flue gas desulfurization system 10, as described above, the seawater from the sea 22 21 Desulfurization of seawater by the sulfur component contained in the exhaust gas 61. Further, the seawater 21 is connected to the seawater 22 by the pump 22a, and after heat exchange in the condenser 53, a part of the absorbed seawater 21a is sent to the seawater flue gas desulfurization system 10 via the seawater supply line L11 via the pump 22b. . Moreover, the diluted seawater 21b is supplied to the upstream side in the inside of the oxidation tank 12 via the diluted seawater supply line L13. The exhaust gas 61 is brought into gas-liquid contact with the absorbing seawater 21a in the flue gas desulfurization absorption tower 11, and the sulfur component in the exhaust gas 61 is absorbed in the absorbing seawater 21a. The exhaust gas 61 purified by the seawater flue gas desulfurization system 10 becomes the purge gas 28 and is discharged to the outside from the chimney 67 via the purge gas discharge passage L15.

Further, the diluted seawater 21c and the air 29 are supplied to the tower bottom portion 11a of the exhaust gas desulfurization absorption tower 11. Therefore, the amount of dissolved oxygen in the sulfur-absorbing seawater 14 can be increased in the flue gas desulfurization absorption tower 11, so that the air blowing distance in the oxidation tank 12 can be reduced as described below, and the length direction of the oxidation tank 12 can be shortened. Therefore, the size of the oxidation tank 12 can be reduced.

The sulfur-absorbing component seawater 14 absorbing the sulfur component is discharged from the flue gas desulfurization absorption tower 11 and then sent to the upstream side of the oxidation tank 12. The upstream side of the inside of the oxidation tank 12 is mixed with the absorbing seawater 21b, and is diluted.

Further, the seawater 21 from the sea 22 is subjected to heat exchange in the condenser 53, and then sent to the seawater flue gas desulfurization system 10 for seawater desulfurization, but it is also possible not to condense the seawater 21 from the sea 22 The heat exchange in the unit 53 is carried out directly to the seawater flue gas desulfurization system 10 for seawater desulfurization.

The sulfur-absorbing seawater 14 is mixed with the absorbing seawater 21b on the side of the oxidation tank 12 before the oxidation tank 12, and then oxidized. In the present embodiment, as described above, the diluted seawater 21c and the air 29 are supplied to the tower bottom portion 11a of the flue gas desulfurization absorption tower 11, and the dissolved oxygen in the sulfur-absorbing component seawater 14 is increased in the flue gas desulfurization absorption tower 11. Therefore, the air blowing distance in the oxidation tank 12 can be reduced, and the length direction of the oxidation tank 12 can be shortened, so that the size of the oxidation tank 12 can be reduced. Further, in the oxidation tank 12, the total amount of air supplied into the oxidation tank 12 can be reduced, so that the power required to supply the air 29 to the oxidation tank 12 can be reduced, and the oxygen can be efficiently opened to the outside. The sulfur-absorbing component seawater 14 flowing in the reforming tank 12 is oxidized to recover the water quality.

The water content of the sulfur-absorbing seawater 14 is recovered in the oxidation tank 12 in the above manner, and the water quality recovery seawater 45 is obtained. The water quality recovery seawater 45 obtained in the oxidation tank 12 discharges the pH value, the dissolved oxygen concentration, and the COD to the level of the seawater to be released from the oxidation tank 12 via the seawater discharge line L18.

Further, a part of the seawater 21 may be supplied from the seawater supply line L11 to the flow side after the water quality recovery seawater 45 in the oxidation tank 12 via the diluted seawater supply line L19. Thereby, the water quality can be further diluted to recover seawater 45. Thereby, the pH value of the seawater recovery seawater 45 can be increased, the pH value of the seawater discharge liquid can be raised to near the seawater, the drainage standard (pH value of 6.0 or more) which satisfies the pH value of the seawater discharge liquid, and the COD can be lowered, and The water quality is restored to the pH value of the seawater 45, and the COD is discharged at the level of the seawater that can be discharged.

Thus, according to the power generation system 50 of the present embodiment, the sulfur-absorbing component seawater 14 discharged from the exhaust gas desulfurization absorption tower 11 can be oxidized by supplying the air 29 to the bottom portion 11a of the tower in the exhaust gas desulfurization absorption tower 11. In the tank 12, the treatment of absorbing the sulfur component seawater 14 is efficiently performed, the air blowing distance in the oxidation tank 12 is reduced, and the size of the oxidation tank 12 can be reduced. Further, the power for supplying the air 29 to the sulfur-absorbing seawater 14 in the oxidation tank 12 can be reduced, and the operation cost can be suppressed. Therefore, the power generation system 50 of the present embodiment can provide a power generation system capable of efficiently and stably processing the sulfur-absorbing seawater 14 and performing water quality recovery processing, and having high safety and reliability.

In the present embodiment, the seawater flue gas desulfurization system 10 is subjected to treatment of the sulfur-absorbing component seawater 14 generated by desulfurization of seawater using the absorbing seawater 21a in the exhaust gas desulfurization absorption tower 11 discharged from the boiler 51. The case has been described, but the present invention is not limited thereto. The seawater flue gas desulfurization system 10 can be used, for example, in exhaust gas discharged from power plants such as factories in various industries, large-scale and medium-sized thermal power plants, and large-scale boilers or general industrial boilers for electric power companies. The removal of sulfur components in the sulfur-absorbing component solution by sulfur oxides by seawater desulfurization.

10‧‧‧Seawater flue gas desulfurization system

11‧‧‧Exhaust flue gas desulfurization absorption tower

11a‧‧‧Absorption tower slot

12‧‧‧oxidation tank

14‧‧‧Sulphur-absorbing seawater

21‧‧‧ seawater

21a‧‧‧absorbing seawater

21b, 21c‧‧‧diluted seawater

22‧‧‧Sea

22a~22e‧‧‧ pump

25‧‧‧Exhaust

26‧‧‧ spray nozzle

28‧‧‧ Purified gas

29‧‧‧ Air

32a, 32b‧‧‧SO ₂ concentration meter

33‧‧‧ Flowmeter

34‧‧‧Control device

41‧‧‧Aeration device (air distribution device)

42‧‧‧Oxidation air blower

43‧‧‧Distribution tube

44‧‧‧Oxidizing air nozzle

45‧‧‧Water quality restores seawater

L11‧‧‧Seawater supply line

L12‧‧‧Air branch line

L13, L14‧‧‧ diluted seawater supply line

L15‧‧‧ Purified gas exhaust passage

L16‧‧‧Seawater circulation line

L17‧‧‧Sulphur-absorbing seawater discharge line

L18‧‧‧Seawater discharge line

Claims (6)

A seawater flue gas desulfurization system, comprising: a flue gas desulfurization absorption tower, which washes the exhaust gas by gas-liquid contact with the seawater; and the oxidation tank is disposed after the flue gas desulfurization absorption tower The side is provided with an air supply means for supplying air to the seawater containing the sulfur component containing the sulfur component, and performing the water quality recovery process of the sulfur-absorbing component seawater; and the seawater supply line for supplying the seawater to the exhaust gas desulfurization absorption tower; a branch line that supplies a portion of the air supplied to the oxidation tank to the bottom of the tower of the flue gas desulfurization absorber; and a dilution seawater supply line that supplies a portion of the seawater as diluted seawater to the flue gas desulfurization absorption The bottom of the tower. The seawater flue gas desulfurization system according to claim 1, wherein the SO ₂ absorption amount is 3 mmol/l or less with respect to the total amount of the seawater supplied to the flue gas desulfurization absorption tower. The seawater flue gas desulfurization system according to claim 1, wherein the temperature of the seawater absorbing sulfur component is 5 ° C or more and 55 ° C or less. The seawater flue gas desulfurization system of claim 1, wherein the seawater has a pH of 5.5 or more. The seawater flue gas desulfurization system of claim 1, comprising: an SO ₂ concentration meter for measuring an inlet SO ₂ concentration of the exhaust gas and an outlet SO ₂ at an inlet and an outlet of the exhaust gas of the flue gas desulfurization absorption tower _; a concentration; a seawater circulation line for circulating the sulfur-absorbing component seawater in the exhaust gas desulfurization absorption tower in the seawater supply line; and a flow meter disposed on the seawater circulation line, and measuring the desulfurization from the smoke exhausting a flow rate of the sulfur-absorbing component seawater extracted by the absorption tower; calculating a desulfurization rate in the exhaust gas desulfurization absorption tower based on the inlet SO ₂ concentration of the exhaust gas and the outlet SO ₂ concentration, and adjusting the supply to the diluted seawater supply line to the The supply amount of seawater in the above oxidation tank. A power generation system, comprising: a boiler; a steam turbine that uses exhaust gas discharged from the boiler as a heat source for steam generation, and uses the generated steam to drive a generator; a sulfur system; a condenser that recovers and circulates water condensed in the steam turbine; a flue gas denitration device that performs denitration of exhaust gas discharged from the boiler; and a dust collecting device that removes the exhaust gas Coal dust.