JP3093744B2 - Flue gas desulfurization equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flue gas desulfurization device, and more particularly to a flue gas desulfurization device in which the desulfurization reaction of sulfur oxide (SOx) contained in exhaust gas is improved.

[0002]

2. Description of the Related Art In a thermal power plant or the like, a so-called flue gas desulfurization device for removing sulfur oxides contained in exhaust gas discharged from a flue gas is usually attached to a power generation facility. Conventionally, in a flue gas desulfurization apparatus, as a method of performing gas-liquid contact between an exhaust gas containing sulfur oxides and an absorbing liquid circulating in the tower, a spray nozzle for spraying the absorbing liquid in a counterflow with the exhaust gas is provided. absorbing agent and the ones contacting gas-liquid gas, with a filling provided in the absorption tower while others to gas-liquid contact, FIG. 6 is a schematic diagram showing a former flue gas desulfurization apparatus, FIG. 8 1 is a schematic diagram of the latter flue gas desulfurization device.

In FIG. 6 , 1 is an exhaust gas, 2 is an absorption tower,
3 is a gas dispersion plate provided in the absorption tower 2 and 4 is an absorption tower 2
Spray pipe provided on the upper part of the inside, 5 is a spray nozzle provided on the spray pipe 4, 6 is an absorbent mist, 7
Is an absorbent supply pipe for supplying the absorbent into the absorption tower 2, 8 is an absorption liquid reservoir provided at a lower portion of the absorption tower 2, and 9 is an absorption liquid reservoir 8.
A circulating pump 10 for sending the absorbing liquid through a spray pipe 4 to a spray nozzle 5 is a treated exhaust gas.

[0004] The exhaust gas 1 is guided into the tower from the lower part of the absorption tower 2, passes through the gas dispersion plate 3 and is sent to the desulfurization reaction section. The gas dispersion plate 3 is used to suppress gas drift and prevent a decrease in desulfurization performance. After the absorbent is supplied into the absorption tower 2 and held in the absorption liquid reservoir 8, the absorbent is pumped up by the circulation pump 9 and pressurized, and sprayed through the spray pipe 4 installed horizontally inside the absorption tower 2. The liquid is sprayed into the tower as fine droplets from the nozzle 5. The exhaust gas 1 sent into the absorption tower 2 comes into gas-liquid contact with the absorption liquid mist 6 sprayed into the tower, and sulfur oxides (SOx) in the exhaust gas are absorbed and absorbed.
After being removed and desulfurized, the treated exhaust gas 10 is sent out of the system.

FIG. 7 is a schematic view showing a cylindrical flue gas desulfurization apparatus disclosed in Japanese Patent Laid-Open No. 6-190240. In this cylindrical flue gas desulfurization device, a duct 15 for supplying exhaust gas is provided above a cylindrical tank 13, and a discharge duct 14 is provided.
Is disposed so as to penetrate from the upper part of the cylindrical tank 13 to the inside, and a spray device 16 is provided at the lower part of the cylindrical tank 13,
An absorbing liquid reservoir 19 for storing absorbing liquid droplets is provided below the lower surface. The exhaust gas flows from the upper duct 15 and turns, contacts the mist-like absorbent 17, absorbs and removes sulfur oxides (SOx) in the exhaust gas, and performs desulfurization. Air is supplied to the outside of the system from a discharge duct 14 that opens downward in the inside 13. Further, as another cylindrical flue gas desulfurization apparatus, there is one disclosed in Japanese Patent Application Laid-Open No. Hei 8-28055.

[0008] The flue gas desulfurization apparatus shown in FIG. 8 is an absorption tower 2 provided with a packed bed B, and a spray pipe 4 provided with a spray nozzle 5 is disposed in the upper part of the absorption tower 2. The absorbing liquid is sprayed from the spray nozzle 5, and when the absorbing liquid flows down the packed bed B, gas-liquid contact between the exhaust gas and the absorbing liquid is performed. The filling layer B is a layer filled with a ring-shaped or saddle-shaped filler made of porcelain, carbon, or steel. The absorbent is supplied from the absorbent supply pipe 7 into the absorption tower 2, and the absorption liquid is pressurized by the circulation pump 9 and sprayed.
Is sprayed from the spray nozzle 5 into the tower. The absorption liquid flows down the packed bed B through which the exhaust gas passes, and the sulfur oxides (SOx) in the exhaust gas are absorbed and removed, thereby performing desulfurization.

[0007]

Flue gas desulfurization apparatus of Fig. 6 - object of the invention is to solve the above-
In order to maintain the efficiency of the desulfurization reaction in the absorption tower, it is necessary to maintain the gas-liquid contact time between the exhaust gas 1 and the absorption liquid mist 6,
The flow velocity of the exhaust gas in the tower is limited to, for example, about 2 m / sec. Therefore, when the amount of exhaust gas flowing into the absorption tower increases, it is necessary to suppress the exhaust gas processing amount and maintain the gas-liquid contact time in order to maintain the gas-liquid contact time. There were drawbacks in processing.

When the amount of exhaust gas to be treated increases, the gas dispersion plate 3 must be provided and the tower diameter must be increased, and the number of spray pipes 4 must be increased to achieve the required desulfurization rate. It was necessary to increase the number of nozzles 5 to increase the amount of the spray absorbing liquid.

On the other hand, in the cylindrical flue gas desulfurization apparatus shown in FIG. 7 , a discharge duct 14 is inserted into a cylindrical tank 13 and an upper duct 15 is inserted.
Exhaust gas 1 that has flowed from
Air flows out of the system through the opening 4. The flow path in the cylindrical tank 13 for the exhaust gas to flow into is a discharge duct 14.
In consideration of the above, the diameter of the cylindrical tank 13 must be set in order to secure a sufficient flow path. Therefore, in order to desulfurize a large amount of exhaust gas, the diameter of the cylindrical tank 13 must be increased, which causes a problem in increasing the size of the apparatus.

[0010] In the smoke desulfurization apparatus having the packed bed shown in Fig. 8 , the exhaust gas passes through the packed bed B and is brought into gas-liquid contact, and the exhaust gas passes through the packed bed B. There is a limit to the flowing speed (superficial tower speed). That is, even if an attempt is made to increase the processing gas amount of the exhaust gas, there is a limit in increasing the superficial velocity due to the presence of the packed bed B.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a flue gas desulfurization apparatus capable of realizing a required desulfurization rate even when the superficial velocity of exhaust gas is increased. Aim. NOx, NH in exhaust gas
_4. It is an object of the present invention to provide a flue gas desulfurization device capable of removing harmful substances such as HCl.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the invention of claim 1 removes sulfur oxides and the like in exhaust gas by spraying an absorbing solution into an absorption tower. In the flue gas desulfurization apparatus, the absorption tower has a vertical cylindrical shape.
As a result, the exhaust gas flowing into the absorption tower turns and rises.
Thus, an exhaust gas inlet is provided at the bottom of the absorption tower, and the
A spray pipe is arranged in the collection tower along the exhaust gas flow path of the absorption tower , and the absorption liquid supplied from the spray pipe is
A flue gas desulfurization apparatus characterized in that spray nozzles for spraying along the flow of the exhaust gas are arranged at appropriate intervals.

In these configurations, a spray pipe through which the absorbent flows along the flow path of the exhaust gas is arranged, and the absorbent is sprayed from the spray nozzle along the flow of the exhaust gas.
Therefore, the required desulfurization rate can be achieved without reducing the flow velocity of the exhaust gas in the tower. Furthermore, since a large number of spray nozzles can be arranged in the spray pipe arranged in the absorption tower in the same manner as the flow of the exhaust gas, it is possible to secure a required amount of the spray-absorbing liquid, and from the spray nozzle toward the inner wall of the tower. By spraying the absorbing liquid horizontally
The effect of forming fine droplets over a wide range in the absorption tower is obtained. That is, it is possible to realize an efficient desulfurization reaction with an excellent space contact efficiency with the absorbing liquid and to increase the flow velocity of the exhaust gas in the tower, thereby making it possible to make the absorbing tower compact. .

Further, the invention according to claim 2 is characterized in that the axis of the absorption tower is
The flue gas desulfurization apparatus according to claim 1 , wherein a plurality of the spray pipes are arranged concentrically around the center .

In this configuration, by disposing a plurality of spray pipes concentrically around the center of the tower axis in the absorption tower, even if the diameter of the absorption tower is larger than the droplet reaching distance of the spray nozzle, the absorption tower can be used. Since high spatial contact efficiency can be maintained over the entire area of the inside, an apparatus having high desulfurization performance even for a large amount of exhaust gas can be realized.

Further, the invention of claim 3, the branch pipes at appropriate intervals before Symbol spray pipe is provided, in that a spray nozzle to spray the absorption liquid in the gas flow direction in the branch pipe The flue gas desulfurization apparatus according to claim 1 or 2, wherein:

According to this configuration, the spray pipe is provided with the spray nozzle, and when the exhaust gas swirls in the tower, the absorbing liquid is sprayed in a mist form from the spray nozzle along the flow of the exhaust gas. Thus, the required desulfurization rate can be realized without reducing the flow rate of the exhaust gas in the tower while maintaining the contact time with the exhaust gas.

[0018] invention, prior Symbol spray pipes arranged is from the vicinity exhaust gas outlet to the exhaust gas inlet vicinity of claim 4
A flue gas desulfurization apparatus according to claim 1, 2 or 3 characterized in that it.

According to this structure, the spray pipe is provided along the flow path of the exhaust gas in the absorption tower, and the exhaust gas can always come into gas-liquid contact with the fresh absorbing liquid while moving from the inlet to the outlet. The required desulfurization rate can be achieved.

Further, the invention of claim 5, claims spraying direction before Symbol absorbing liquid by the spray nozzle is characterized in that the turning direction in the same direction or the tangential direction of the exhaust gas
A flue gas desulfurization device according to 1, 2, 3, or 4 .

According to this configuration, the spray mist is discharged.
By flowing in the swirling direction of the gas and being centrifuged to the inner wall of the cylindrical column and adhering to the wall, the amount of droplets of the absorbing liquid entrained in the treated exhaust gas is reduced.

Further, according to this configuration, by spraying the absorption liquid in the flow direction of the exhaust gas, since the contact time with the sulfur oxides in the exhaust gas and the absorption liquid can be sufficiently ensured, desulfurization Excellent performance, and the exhaust gas flow rate in the tower is 5
m / sec.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a flue gas desulfurization apparatus according to the present invention will be described below with reference to the drawings.

First, an embodiment of the present invention will be described with reference to FIG.
Will be described with reference to the schematic diagram of FIG. In FIG. 1, an absorption tower (or absorption tank) 2 has, for example, a cylindrical shape. 8 are provided. Absorbent A in which the absorbent is dissolved
The spray pipe 4, which is a flow path, is installed vertically along the axial center of the tower. Spray nozzles 5 are attached to the spray pipe 4 in multiple stages at appropriate intervals (usually at equal intervals). The spray pipe 4 extends downward, for example, from the vicinity of the treated exhaust gas discharge port 2b in the upper part of the absorption tower 2, and its tip portion is hung down to the vicinity of the exhaust gas inlet 2a.

The exhaust gas 1 is introduced from the exhaust gas inlet 2a at the lower part of the absorption tower 2, and the absorption liquid A is pumped up from the absorption liquid reservoir 8 by the circulation pump 9, and is pressurized by the circulation pump 9;
The spray is sprayed horizontally from the spray nozzle 5 toward the inner wall of the tower through the spray pipe 4. Exhaust gas inlet 2a
The exhaust gas 1 introduced from the exhaust gas is brought into desulfurization contact by gas-liquid contact with the spray mist 6 of the above-mentioned sprayed absorbent, and the sulfur oxides and the absorbent in the exhaust gas undergo a desulfurization reaction, so that Of SOx are absorbed and removed. The desulfurized exhaust gas is sent as a treated exhaust gas 10 from the outlet 2b at the top of the absorption tower. The absorbent is alkaline, and magnesium hydroxide, slaked lime, quicklime, caustic soda, aqueous ammonia, and the like are used.

The above "vertically along the axial center of the tower"
Corresponds to the direction of the exhaust gas flow path, and means "the axial direction of the tower". The "exhaust gas flow path" is formed by the exhaust gas flowing vertically or horizontally from the inflow port 2a into the tower while turning. It refers to the axial flow of the tower flowing to the upper outlet 2b.

Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a schematic perspective view in which a part of another embodiment of the present invention is cut away, and FIG.
2 is a sectional view of a main part of FIG. In FIG. 2, the absorption tower 2 is provided with an exhaust gas inlet and an absorption liquid reservoir for the absorption liquid A at its lower part as shown in FIG. 1, and inside the absorption tower 2 along the axial direction of the tower. A plurality of spray pipes 4 are arranged symmetrically with respect to the axis. As described above, the plurality of spray pipes 4 may be arranged concentrically with respect to, for example, the axial center of the tower. The spray pipes 4 are provided with spray nozzles 5 at appropriate intervals (usually at equal intervals). As shown in FIG. 3, the spray nozzle 5 has four spray pipes 4 arranged therein, and the direction of the absorbing solution A sprayed from the spray nozzle 5 is horizontal and the cylindrical absorbing tower 2 has a cylindrical shape.
Are tangential directions. The axial direction of the tower corresponds to the direction of the exhaust gas flow path, and the exhaust gas flows from the inflow port 2a to the upper discharge port 2b while rotating vertically or inside the tower.

In the present embodiment, by disposing a plurality of spray pipes 4 in the tower, the number of spray nozzles 5 arranged in the spray pipes 4 can be increased, and the spray amount of the absorbing liquid A can be increased. it can. Therefore, even when the tower diameter is increased in accordance with the amount of exhaust gas, or when the distance becomes longer than the reach of the absorbing liquid mist 6 sprayed from the spray nozzle 5, as shown in the embodiment of FIG. By arranging the spray arrangement, it is possible to cover the entire inside of the absorption tower, and it can be applied to the case of a large absorption tower 2. Therefore, as in the present embodiment, the spray pipe 4
When four are arranged, as shown in FIG. 3, the spray direction of the absorbing liquid from the spray nozzle 5 is clearly superior to the case of the single spray pipe 4 in the space contact efficiency. .

Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a schematic perspective view in which a part of another embodiment of the present invention is cut away, and FIG. 5 is a sectional view of a main part of FIG. FIG. 4 shows a configuration of a cylindrical flue gas desulfurization apparatus according to the present invention.
As shown in the figure, an exhaust gas inlet and an absorbing liquid reservoir for the absorbing liquid A are provided at the lower part thereof. The spray pipe 4 is installed so as to hang down at the center of the axis of the absorption tower 2 as in FIG. That is, the spray pipe 4 is vertically provided along the exhaust gas flow path. The spray pipe 4 is provided with branch pipes 4a perpendicular to the spray pipe 4, and a spray nozzle 5 at each end thereof. It is preferable that the branch pipe 4a is as short as possible, as shown in FIG. 5, and the spray direction from the spray nozzle 5 is horizontal and tangential to the swirling flow 12.

In this embodiment, the exhaust gas is absorbed by the absorption tower 2.
Are introduced tangentially to the horizontal cross section of The exhaust gas forms a swirl flow 12 inside the tower. The spray direction from the spray nozzle 5 in this case is a tangential direction of the swirl flow 12 as shown in FIG. 5, and the swirl flow 12 of the exhaust gas can be promoted to reduce the pressure loss in the exhaust gas inflow. The gas-liquid contact time can be maintained long by increasing the distance between the absorbing liquid and the spray mist 6 to the inner wall of the tower, thereby improving the efficiency of the desulfurization reaction.

Since the absorbing liquid is jetted from the spray nozzle 5 toward the inner wall of the tower, the spray mist 6
Is centrifuged to the inner wall of the cylindrical column, so that the amount of droplets accompanying the treated exhaust gas 10 is also reduced. Therefore, it is important to pump up the absorbing liquid with a circulation pump and to increase the pressure to such an extent that the droplets adhere to the inner wall of the absorption tower.

Next, in order to verify the effectiveness of the flue gas desulfurization apparatus of the present invention, the embodiment of FIG. 1 and the conventional example of FIG. 8 will be described. In this verification, the flue gas desulfurization apparatus of FIG. 8,
Exhaust gas was treated with improvements as shown in FIG. Exhaust gas mixed with sulfur oxide, which is the same harmful substance, was fed into these devices for processing. As an absorbent, caustic soda (NaOH) was used for both. Under such processing conditions, both measurements were made, and the processing gas amount, desulfurization rate, and superficial velocity were compared and examined. Table 1
Shows the result. In addition, as shown in Table 1, the diameter of the absorption tower used was smaller in the flue gas desulfurization apparatus of the present invention.

[0033]

[Table 1]

As is clear from Table 1, each apparatus of the present invention and the conventional example achieves a desulfurization rate of ≧ 99%. Although the diameter of the absorption tower of the present invention is smaller than the conventional diameter, the processing gas amount is larger than the conventional example. The superficial velocity was improved from 2.1 m / s to 5.7 m / s. From these effects, it has become apparent that the flue gas desulfurization apparatus of the present invention can obtain extremely remarkable effects.

As described above, in the present embodiment, the exhaust gas containing sulfur oxide flows in the swirl flow or the vertical direction in the absorption tower, and the sulfur oxide mixed in the exhaust gas comes into gas-liquid contact with the absorbing solution. The exhaust gas rises while undergoing a desulfurization reaction, and the treated exhaust gas is supplied. By extending the spray pipe provided along the exhaust gas flow path in the longitudinal direction of the absorption tower or the absorption tank, the spray mist sprayed to the entire inside of the absorption tower or the absorption tank is filled, and the desulfurization reaction is performed. It can be implemented reliably. Therefore, the absorption tower can be configured to also serve as a chimney, and the desulfurization efficiency can be maintained even in a place with a small site area by increasing the overall length even when the diameter is small. Can be.

In the embodiment described with reference to FIGS. 1 to 5, the sulfur oxides in the exhaust gas are brought into gas-liquid contact with the absorbing liquid,
If has been described flue gas desulfurization apparatus for desulfurizing, without limiting to this embodiment, as harmful substances in the exhaust gas, not only sulfur oxides only, NOx, NH _4, HCl and the like Ru <br/> be mixed However, these acidic substances can be removed. Of course, in the exhaust gas, with respect to the content of sulfur oxides <br/>, NOx, similar removal effect even if the content is large in NH _4, HCl or the like is achieved. Furthermore, N
Even if the exhaust gas is mainly composed of harmful substances such as Ox, NH ₄ and HCl, such harmful substances can be removed, and the flue gas desulfurization apparatus of the present invention is also effective as a harmful substance absorption apparatus. Is included.

[0037]

As described above, according to the present invention, a large number of spray nozzles can be arranged in the direction of the flow path of exhaust gas, so that the effect of forming fine droplets over a wide range in the absorption tower can be obtained. Since it is not necessary to expand the absorption tower in the lateral direction to obtain a desired desulfurization rate, there is an advantage that the apparatus itself can be made compact.

Further, in the prior art, in order to treat a large amount of exhaust gas, the size of the absorption tower in the lateral direction is enlarged, the drift of the exhaust gas is likely to occur, and a gas dispersion plate is required. According to the method, a gas dispersion plate is not required, and a simple absorption tower structure in which a spray pipe is provided in parallel with a gas flow path so as not to block a gas flow is possible, so that pressure loss can be reduced.

Further, according to the present invention, by arranging in parallel the spray pipe a plurality of, good desulfurization efficiency, Ki out to uniformly spray the absorption liquid to a wide range of the absorption tower, high desulfurization The performance and the size of the absorption tower can be increased.

Further, according to the present invention, since the flow velocity in the tower can be increased, the spray mist is centrifuged to the inner wall of the cylindrical tank, so that the spray mist is entrained from the treated gas discharge port to the exhaust gas duct. Spray mist entrainment is also reduced.

Further, according to the present invention, when containing the Dazuto the exhaust gas, dust is current capturing the inner wall by colliding with the absorption liquid to be sprayed centrifugal force due to the swirling flow of the gas, and the tower inner wall direction Therefore, it is effective in removing dust mixed in the exhaust gas together with the desulfurization reaction.

The flue gas desulfurization apparatus of the present invention is a harmful substance absorption apparatus capable of removing not only sulfur oxides but also acidic harmful substances such as NOx, NH ₄ and HCl.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a flue gas desulfurization apparatus according to the present invention.

FIG. 2 is a partially cut-away schematic perspective view showing another embodiment of the flue gas desulfurization apparatus according to the present invention.

FIG. 3 is a sectional view of a main part of FIG.

FIG. 4 is a partially cut-away schematic perspective view showing another embodiment of the flue gas desulfurization apparatus according to the present invention.

FIG. 5 is a sectional view of a main part of FIG.

FIG. 6 is a schematic view showing an example of a conventional flue gas desulfurization device .

FIG. 7 is a schematic view showing another example of a conventional cylindrical flue gas desulfurization device.

FIG. 8 is a schematic view showing another example of a conventional packed tower type flue gas desulfurization apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust gas 2 Absorption tower (absorption tank) 2a Exhaust gas inlet 2b Treated gas outlet 4 Spray pipe 4a Branch pipe 5 Spray nozzle 6 Spray mist 7 Absorbent supply pipe 8 Absorbent liquid reservoir 9 Circulation pump 10 Treated exhaust gas 12 Exhaust gas turning Flow A Absorbent

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Yokoyama 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Koji Kihara 1-26-6 Kameido, Koto-ku, Tokyo Nissan Engineering Inside (72) Inventor Tsunetomi Ono 1-28-6 Kameido, Koto-ku, Tokyo Nissan Engineering Co., Ltd. (72) Inventor Kaoru 1-28-6 Kameido, Koto-ku, Tokyo Nissan Engineering Co., Ltd. (56) References JP-A-8-281055 (JP, A) JP-A-6-343825 (JP, A) JP-A-52-91777 (JP, A) Registered utility model 3054123 (JP, U) 51-33796 (JP, B2) JP-B-56-28169 (JP, B2) JP-T4-5044976 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 53 / 18 B01D 53/34-53/85

Claims (5)

(57) [Claims] 1. A flue gas desulfurization apparatus for removing sulfur oxides and the like in exhaust gas by spraying an absorbing liquid into an absorption tower, wherein the absorption tower has a vertical cylindrical shape and flows into the absorption tower. An exhaust gas inlet is provided at the lower part of the absorption tower so that the exhaust gas turns and rises, and a spray pipe is arranged in the absorption tower along the exhaust gas flow path of the absorption tower, and supplied from the spray pipe. A flue gas desulfurization apparatus characterized in that spray nozzles for spraying the absorbing solution to be sprayed along the flow of the exhaust gas are arranged at appropriate intervals. 2. A concentric circle centered on the axis of the absorption tower,
The flue gas desulfurization device according to claim 1, wherein a plurality of the spray pipes are arranged. 3. The spray pipe according to claim 1, wherein branch pipes are provided at appropriate intervals in the spray pipe, and a spray nozzle is provided in the branch pipe so as to spray the absorbing liquid in an exhaust gas flow direction. 2. The flue gas desulfurization device according to item 1. 4. The flue gas desulfurization apparatus according to claim 1, wherein the spray pipe is provided from a portion near the exhaust gas outlet to a portion near the exhaust gas inlet. 5. The flue gas desulfurization apparatus according to claim 1, wherein the spray direction of the absorbent by the spray nozzle is the same as the turning direction of the exhaust gas or the tangential direction.