JP5974741B2 - Flue gas desulfurization equipment - Google Patents

Description

The present invention absorbs sulfur oxide (hereinafter referred to as SO _X ) in the exhaust gas by bringing the absorption liquid (limestone slurry) into contact with the exhaust gas inside the absorption tower, and the absorption liquid that has absorbed SO _X is constant in the circulation tank. and the amount stored is blown with air to oxidize the SO ₂ in the absorbent solution by contact with a bubble to generate a plaster absorption liquid circulation tank, the absorption solution circulating tank circulating pump from the suction port of the circulation tank sidewall In particular, the exhaust gas desulfurization apparatus is designed to circulate and supply to the spray apparatus provided at the upper part of the absorption tower, and in particular, air is sucked into the circulation pump in a state where the mixing and dispersibility of bubbles in the absorption liquid is improved. The present invention relates to a flue gas desulfurization apparatus that suppresses the occurrence of the above.

In recent years, the deterioration of the natural environment due to air pollution has been highlighted, and in thermal power plants, SO _X in exhaust gas generated by the combustion of fossil fuel is the main cause of environmental problems such as air pollution and acid rain. Since it is considered to be one, the spread of flue gas desulfurization equipment for SO _X removal is being promoted.

  As for the present flue gas desulfurization apparatus, the wet method based on the limestone-gypsum method occupies the mainstream, and among them, the most proven and highly reliable spray type flue gas desulfurization apparatus is adopted. This spray-type flue gas desulfurization apparatus has high desulfurization performance, and the basic technology is almost established.

In flue gas desulfurization apparatus of such a spray method, since the the SO ₂ in the absorbing solution is oxidized to produce gypsum by contact with the bubble by blowing air into the absorbing liquid, in the absorbent liquid in the circulation tank An air blowing device (oxidation device) that blows air, improves the mixing and dispersibility of bubbles in the absorption liquid, and prevents particles (limestone, gypsum) in the absorption liquid in the circulation tank from settling. And a stirrer. In recent years, an oxidation stirrer in which air bubbles that have been made fine by shearing air with blades of a stirrer are mixed with an absorbing solution has been adopted to improve oxidation performance.

  Stirring by a stirrer provided in the flue gas desulfurization apparatus is not preferable for each stirrer to stir in its own direction for the purpose of effectively mixing and dispersing bubbles in the absorbing liquid and preventing particle settling, Each stirrer is installed in an inclined manner in the same tangential direction with respect to the circulation tank so that a swirling flow is formed in the circulation tank by the absorbing liquid.

However, in recent years, there are cases where it is required to burn coal having a higher SO ₂ content than normal coal in a boiler. In such a case, the amount of oxidized air is increased or the number of installed stirrers is increased. It is necessary to add more. However, there is a problem that it is difficult to mix and diffuse air well in the absorbing solution.

  As described above, there is a problem that it is difficult to mix and diffuse air into the absorption liquid. When the amount of oxidized air is increased or the number of installed stirrers is increased, air is easily sucked into the circulation pump. As a result, there arises a problem that the circulating pump is vibrated (cavitation) and the life is shortened, or the performance of the circulating pump is lowered.

  Therefore, a baffle that has an opening between the suction port side of the circulation pump inside the absorption tower and the side opposite to the suction port and the bottom plate of the circulation tank and divides the upper part of the circulation tank into two parts. There exists what provided the board (refer patent document 1).

  However, in Patent Document 1, a baffle plate that divides the circulation tank into two parts is provided. Therefore, even if an attempt is made to generate a swirling flow of the absorbing liquid in the circulation tank by a plurality of agitators, the flow is blocked by the baffle plate. Therefore, there is a problem that the flow of the absorbing liquid is disturbed, and the mixing / dispersibility of bubbles in the absorbing liquid cannot be improved, and it is difficult for the absorbing liquid to flow between the baffle plate and the suction port. In addition, there is a problem that particles are deposited between the baffle plate and the suction port. Further, the baffle plate provided so as to be divided into two parts up to the upper part of the circulation tank has a problem that the structure becomes very large, the equipment cost increases, and the maintenance becomes difficult.

  On the other hand, there is one in which a small baffle plate is provided in the inside of the absorption liquid of the circulation tank as compared with Patent Document 1 (see Patent Documents 2 and 3).

JP 2002-253925 A JP 2001-120946 A JP 2001-246224 A

  The baffle plates shown in Patent Documents 2 and 3 have a height that is immersed in the absorption liquid of the circulation tank, and are arranged in the circulation tank that is spaced from the suction port of the circulation pump. Both ends of the unit are fixed to the side wall of the circulation tank. Therefore, the baffle plate has a shape surrounding the suction port in a plan view.

  However, as shown in Patent Documents 2 and 3, in a baffle plate installed so as to surround the suction port, when a swirl flow is formed in the circulation tank by each stirrer, the baffle plate flows by the baffle plate. Since the flow is disturbed and the flow is disturbed, there is a problem in that the mixing / dispersibility of bubbles with respect to the absorbing liquid is lowered. Further, in Patent Documents 2 and 3, there is a problem in that particles accumulate between the baffle plate and the suction port because the flow of the absorbing liquid does not occur between the baffle plate and the suction port and does not occur. Further, in Patent Documents 2 and 3, since the disturbance of the flow of the absorption liquid is caused in the circulation tank by the stirrer, the absorption liquid containing bubbles riding on the disturbance of the flow of the absorption liquid gets over the baffle plate and the baffle plate The air flowed into the inside (suction port side), and thus air could be sucked into the circulation pump via the suction port.

  The present invention has been made in view of the above-mentioned conventional problems, and in a state where the mixing and dispersibility of bubbles with respect to the absorbing liquid is enhanced, the flue gas desulfurization is configured to suppress the suction of air to the circulation pump. The device is to be provided.

The present invention is provided with an absorption tower having a circulation tank for storing an absorption liquid that has absorbed SO _X in the exhaust gas by introducing the exhaust gas discharged from the combustion apparatus and bringing it into contact with the absorption liquid, and a side wall of the circulation tank. An air blowing pipe for oxidizing the absorbing liquid, an agitator arranged on the side wall of the circulation tank so as to stir the absorbing liquid and form a swirling flow by the absorbing liquid in the circulation tank, and absorption in the circulation tank A flue gas desulfurization device having a circulation pump that takes out the liquid from the suction port and circulates and supplies it to the spray device above the absorption tower,
A perforated baffle plate having a height to be immersed in the absorption liquid of the circulation tank at a position close to the side wall and facing the suction port inside the circulation tank and having a through hole on the entire surface. Is fixed,
The perforated baffle plate has a lower opening between the bottom plate of the circulation tank, flue gas desulfurization apparatus characterized by having a communication distance between the side walls of the circulation tank and the side ends, It is related to.

In the flue gas desulfurization device, below the perforated projecting legs at the bottom of the side ends of the baffle plate, by fixing the legs to the bottom plate of the circulation tank, the perforated baffle plate it is preferable that the formation of the lower opening on the side.

In the above flue gas desulfurization apparatus, the perforated baffle plate preferably has a curved shape along the side wall of the circulation tank.

In the above flue gas desulfurization apparatus, the perforated baffle plate is preferably a plurality of divided plates are arranged to be curved along the side walls of the circulation tank.

  In the flue gas desulfurization apparatus, a swirling flow of the absorbing liquid is formed in the circulation tank by the stirrer, and the absorbing liquid communicates between the perforated baffle plate and the suction port on one inlet side. It is preferable that one of the stirrers is arranged to stir downstream at the position of the outgoing communication interval when flowing from the interval toward the other outgoing communication interval.

  According to the present invention, when stirring by the stirrer is performed so that a swirling flow of the absorbing liquid is formed in the circulation tank, a flow of the absorbing liquid is also formed between the perforated baffle plate and the suction port. Since a stable swirl flow is formed in the entire tank, mixing and diffusion of bubbles with respect to the absorbing liquid can be stably increased, and the absorbing liquid flows between the perforated baffle plate and the suction port. As a result, the problem of particle accumulation on this part can be prevented, and further, when the absorbing liquid in the circulation tank is sucked into the suction port through the through hole of the perforated baffle plate, the bubble separation effect by the perforated baffle plate is obtained. Since it works, the outstanding effect that the problem by which air is attracted | sucked by a circulation pump can be reduced can be show | played.

(A) is a cutting plan view of a flue gas desulfurization apparatus provided with a curved perforated baffle plate in a circulation tank according to an embodiment of the present invention, and (b) is a perforated baffle plate provided in (a) IB- It is the front view seen from IB direction. (A) is a cut side view of the perforated baffle plate provided in FIG. 1 as viewed from the direction II in FIG. 1 (a), and (b) is a cut when the perforated baffle plate of (a) is provided with an inclination. It is a side view. (A) is a cutting plan view showing an embodiment in which the perforated baffle plate of FIG. 1 is constituted by a plurality of divided plates arranged along the side wall of the circulation tank, and (b) is a curved perforated baffle plate of FIG. It is a cutting | disconnection top view which shows the Example which used as a straight perforated baffle board. It is a cutting side view showing the whole composition of the flue gas desulfurization device to which the present invention is applied.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 4 shows the overall configuration of the flue gas desulfurization apparatus of the present invention. The flue gas desulfurization apparatus 1 introduces an exhaust gas G discharged from a combustion apparatus such as a boiler through an exhaust gas introduction pipe 2 and makes contact with the absorbing liquid K. In the lower part of the absorption tower 3, a circulation tank 4 is integrally formed in the lower part of the absorption tower 3 for storing the absorption liquid K that has absorbed SO _X in the exhaust gas G.

  In the side wall 4a of the circulation tank 4, an air blowing pipe 5 for blowing the air for oxidizing the absorbing liquid into the absorbing liquid K, and a blowing port 5a of the air blowing pipe 5 are arranged close to the blowing port 5a. A plurality of stirrers 6 for mixing and diffusing the air blown from the inside into the absorbing liquid K are provided. 6 a is a screw of the stirrer 6.

A suction port 7 for taking out the absorption liquid K of the circulation tank 4 is provided at a position near the bottom plate 4 b on the side wall 4 a of the circulation tank 4, and the absorption liquid K sucked by the suction port 7 is further removed from the absorption tower 3. A circulation pump 9 is circulated and supplied to the spray device 8 provided at the top. FIG. 1A shows a case where three circulation pumps 9 are provided. In FIG. 4 , reference numeral 10 denotes a mist collecting unit provided in the exhaust gas outlet pipe 11 connected to the upper end of the absorption tower 3.

  A plurality of agitators 6 provided on the side wall 4a of the circulation tank 4 are formed on the side wall 4a of the circulation tank 4 so as to form a swirl flow R by the absorbing liquid K in the circulation tank 4 as shown in FIG. On the other hand, they are disposed tangentially at an angle α in the same direction, and the blowing port 5a of the air blowing pipe 5 is disposed corresponding to a proximity position in front of the stirring device 6 in the stirring direction. Further, as shown in FIG. 4, the stirrer 6 is installed such that the stirring direction is an angle β downward from the horizontal.

  As shown in FIGS. 4 and 1, the circulation tank 4 is located at a position spaced apart from the suction port 7, and has a height so as to be immersed in the absorption liquid K of the circulation tank 4, and has a through hole 12 on the entire surface. A perforated baffle plate 13 is provided.

  As shown in FIG. 1 (b), the perforated baffle plate 13 has leg portions 15 projecting from the lower portions of the side end portions 14 a and 14 b, and the leg portions 15 are connected to the bottom plate 4 b of the circulation tank 4. Accordingly, the lower opening 16 is formed on the lower side of the perforated baffle plate 13. Although FIG. 1B shows a case where two leg portions 15 are provided, three or more leg portions 15 may be provided. The perforated baffle plate 13 can be formed using a punching metal, a net plate, or the like, and the perforated baffle plate 13 is made of the same material as the absorption tower 3 such as stainless steel (SUS316L), stainless clad. Steel, a lining material, a rubber lining material, etc. can be used.

  The perforated baffle plate 13 shown in FIG. 1A has a curved shape (arc shape) along the side wall 4a of the circulation tank 4 having a cylindrical shape. There are communication intervals 17a and 17b between the side ends 14a and 14b and the side wall 4a of the circulation tank 4, so that the side ends 14a and 14b of the perforated baffle plate 13 and the circulation tank 4 are connected to each other. A flow path 17 is formed between the side wall 4a.

  Further, a swirl flow R of the absorbing liquid K is formed in the circulation tank 4 by the agitator 6, and the absorbing liquid K communicates between the perforated baffle plate 13 and the suction port 7 on one inlet side. One stirrer 6 'is installed at the position of the outlet side communication interval 17b when flowing through the flow path 17 from the interval 17a toward the other outlet side communication interval 17b so as to stir downstream.

  The perforated baffle plate 13 may be installed perpendicular to the bottom plate 4b of the circulation tank 4 as shown in FIG. 2 (a), and the circulation baffle plate 13 as shown in FIG. 2 (b). You may incline and install so that an upper end may approach the suction port 7 side with respect to the baseplate 4b of the tank 4. FIG.

  Next, the operation of the above embodiment will be described.

4, the exhaust gas G from the combustion device such as a boiler (not shown) is introduced from the exhaust gas inlet pipe 2 to the inside of the absorption tower 3, SO _X by contact absorption liquid K and gas-liquid sprayed from the spray device 8 Is absorbed and dust is removed to form a clean exhaust gas. After the mist accompanying the mist collecting section 10 provided in the exhaust gas outlet pipe 11 is removed, the exhaust gas is discharged.

On the other hand, the absorption liquid K that has absorbed SO _X by gas-liquid contact inside the absorption tower 3 descends in the absorption tower 3 and is temporarily stored in the circulation tank 4. In the circulation tank 4, the air supplied from the air blowing pipe 5 is refined by the stirrer 6 and dissolved in the absorbing liquid K. In the circulation tank 4, the sulfur oxide (SO ₂ ) absorbed in the absorption liquid K reacts with limestone (CaCO ₃ ) contained in the absorption liquid K, and is further oxidized by the air supplied to the circulation tank 4. Gypsum (CaSO ₄ .2H ₂ O).

  At this time, if the stirrers 6 provided on the side wall 4a of the circulation tank 4 are arranged so that the swirl flow R of the absorbent K is formed in the circulation tank 4 as shown in FIG. Since the baffle plate 13 has communication spaces 17a and 17b between its side ends 14a and 14b and the side wall 4a of the circulation tank 4, the flow between the perforated baffle plate 13 and the suction port 7 can be reduced. A flow of the absorbing liquid K is also formed in the passage 17, and thus a swirling flow R of the absorbing liquid K is formed in the entire inside of the circulation tank 4.

  Further, since the single stirrer 6 ′ is disposed at the position of the communication interval 17b on the outlet side by the perforated baffle plate 13 so as to stir downstream, the stirrer 6 ′ has the perforated baffle plate 13 and the suction port. 7, the flow of the absorbent K in the flow path 17 can be assisted.

  Thus, a reliable flow of the absorbing liquid K is also formed in the flow path 17 between the perforated baffle plate 13 and the suction port 7, and a stable swirl flow R is formed in the circulation tank 4. It is possible to stably mix and diffuse bubbles with respect to the absorbing liquid K.

  Further, the flow of the absorbing liquid K is formed in the flow path 17 between the perforated baffle plate 13 and the suction port 7, and the lower opening 16 is provided at the lower part of the perforated baffle plate 13. It is possible to prevent the problem that particles settle and deposit around the perforated baffle plate 13 and the suction port 7 and around the perforated baffle plate 13.

  Further, the absorbing liquid K in the circulation tank 4 is sucked into the suction port 7 through the through hole 12 of the perforated baffle plate 13, but the absorbing liquid K passes through the through hole 12 of the perforated baffle plate 13. In this case, since the bubble separation effect that bubbles are separated by reducing the flow path and increasing the pressure works, the problem that air is sucked into the circulation pump 9 from the suction port 7 is reduced.

  Further, since the perforated baffle plate 13 has a simple configuration, the perforated baffle plate 13 can be implemented at low cost, and further has an advantage that maintenance work at the time of operation stop is facilitated.

  In FIG. 3A, the perforated baffle plate 13 shown in FIG. 1 is composed of a plurality of divided plates 18, and the plurality of divided plates 18 are bent along the side wall 4a of the circulation tank 4. An example of arrangement is shown. According to the embodiment of FIG. 3A, the perforated baffle plate 13 can be easily manufactured and installed by using the divided plate 18 having a small area.

  FIG. 3B shows a case where the curved perforated baffle plate 13 shown in FIG. 1 is a straight perforated baffle plate 19. In such a straight perforated baffle plate 19, FIG. In addition, the same effect as the curved perforated baffle plate 13 can be exhibited.

  In addition, the flue gas desulfurization apparatus of the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Flue gas desulfurization apparatus 3 Absorption tower 4 Circulation tank 4a Side wall 4b Bottom plate 5 Air blowing pipe 6 Stirrer 6 'Stirrer 7 Suction port 8 Sprayer 9 Circulation pump 12 Through-hole 13 Perforated baffle plate 14a, 14b Side both ends 15 Leg 16 Lower opening 17a, 17b Communication interval 18 Dividing plate G Exhaust gas K Absorbing liquid R Swirl

Claims (5)

An absorption tower having a circulation tank for storing an absorption liquid that has absorbed SO _X in the exhaust gas by introducing the exhaust gas discharged from the combustion device and bringing it into contact with the absorption liquid, and for absorbing liquid oxidation provided on the side wall of the circulation tank An air blowing pipe, a stirrer arranged on the side wall of the circulation tank to stir the absorption liquid and form a swirling flow by the absorption liquid in the circulation tank, and a suction port for the absorption liquid in the circulation tank A flue gas desulfurization device having a circulation pump that is removed from the circulation tower and circulated and supplied to the spray device at the top of the absorption tower,
A perforated baffle plate having a height to be immersed in the absorption liquid of the circulation tank at a position close to the side wall and facing the suction port inside the circulation tank and having a through hole on the entire surface. Is fixed,
The perforated baffle plate has a lower opening between the bottom plate of the circulation tank, flue gas desulfurization apparatus characterized by having a communication distance between the side walls of the circulation tank and the side ends. Projecting legs at the bottom of the side ends of the perforated baffle plates, by fixing the legs to the bottom plate of the circulation tank, forming the lower opening on the lower side of the perforated baffle plate The flue gas desulfurization apparatus according to claim 1. The perforated baffle plate, flue gas desulfurization apparatus according to claim 1 or 2, characterized in that it has a curved shape along the side wall of the circulation tank. The perforated baffle plate, flue gas desulfurization apparatus according to claim 1 or 2, wherein a plurality of divided plates are arranged to be curved along the side walls of the circulation tank.   A swirling flow of the absorbing liquid is formed in the circulation tank by the stirrer, and the absorbing liquid passes from the communication interval on one inlet side to the communication interval on the other outlet side between the perforated baffle plate and the suction port. The exhaust according to any one of claims 1 to 4, wherein one of the stirrers is disposed so as to stir downstream in a position of the communication interval on the outlet side when flowing toward the bottom. Smoke desulfurization equipment.

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