JP2013111527A - Wet-type flue gas desulfurization apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet-type flue gas desulfurization apparatus of which the desulfurization performance is improved by preventing the blow-through or drift of a gas without considerably increasing facility costs or motive power.SOLUTION: The wet-type flue gas desulfurization apparatus comprises an absorption tower 1 including an exhaust gas inlet 13, a spray nozzle 10 which sprays an absorption liquid to a rising exhaust gas, a tank 6 for storing the absorption liquid, a circulation pipeline 8 for feeding the absorption liquid in the tank 6 to the spray nozzle 10, and an exhaust gas outlet 14. In the wet-type flue gas desulfurization apparatus, a plurality of stages of spray headers 9 each including a plurality of spray nozzles 10 are provided in a vertical direction, for each circulation pipeline 8 connected to the spray header 9 of each stage, a single pipe is provided which penetrates an absorption tower 1 from a single spot on a sidewall of the tower. Each of the spray headers 9 includes a main spray header 11 and a plurality of sub spray headers 12. The main spray header 11 is connected, approximately in its center, to the circulation pipeline 8 and extends in the peripheral direction of the inner wall of the absorption tower 1. Each of the plurality of the sub spray headers 12 is branched from the main spray header 11 and extends in a penetration direction of the circulation pipeline 8. Therefore, man-hour for manufacturing the apparatus is decreased and the gas can be suppressed from flowing through the vicinity of the inner wall of the absorption tower 1.

Description

  The present invention relates to an exhaust gas treatment apparatus that removes sulfur oxide, which is a harmful component in exhaust gas, and in particular, can reduce the cost of the absorption tower, and also in the vicinity of the gas drift in the absorption tower and the inner wall of the absorption tower. The present invention relates to a wet type flue gas desulfurization apparatus capable of suppressing gas blow-by.

  In thermal power plants and the like, wet limestone-gypsum flue gas desulfurization devices have been widely put into practical use as devices for removing sulfur oxides in exhaust gas generated by the combustion of fossil fuels in order to prevent air pollution. FIG. 8 shows an absorption tower (side view) in a conventional wet flue gas desulfurization apparatus, and FIG. 9 shows a plan view of a spray header portion of the absorption tower of FIG.

  This wet flue gas desulfurization apparatus mainly includes an absorption tower 1, an inlet duct 2 for introducing exhaust gas into the absorption tower 1, an outlet duct 3 for discharging exhaust gas from the absorption tower 1, and a flow direction of the exhaust gas. A spray header 9 provided with a plurality of stages and provided with a number of spray nozzles 10 for spraying the absorbing liquid 5 to the exhaust gas introduced from the inlet duct 2, a circulation tank 6 for storing the absorbing liquid sprayed from the spray nozzle 10, and a circulation Absorbing liquid circulation pipe 8 for circulating the absorbing liquid in the tank 6 to the spray header 9, an absorbing liquid circulation pump 4 for feeding liquid provided in the absorbing liquid circulation pipe 8, and minute droplets accompanying the flow of exhaust gas It comprises a mist eliminator 7 for removing (mist).

  Exhaust gas containing sulfur oxides discharged from a combustion apparatus such as a boiler installed in a thermal power plant or factory is absorbed in a horizontal direction (arrow X direction) from an inlet duct 2 by a desulfurization fan (not shown). And then discharged from the outlet duct 3 provided at the top of the absorption tower 1 in the direction of arrow Y. During this time, the absorbent 5 containing an absorbent such as limestone (calcium carbonate) or slurry containing lime sent from the absorbent circulating pump 4 is sprayed from a plurality of spray nozzles 10 attached to the spray header 9. By contacting the droplets of the absorbent sprayed as fine droplets from the spray nozzle 10 with the exhaust gas, the exhaust gas together with soot, hydrogen chloride (HCl), and hydrogen fluoride (HF) in the exhaust gas. The sulfur oxide (SOx) is chemically absorbed and removed by the surface of the absorbing droplet of the spray nozzle 10.

  The absorbent 5 that has absorbed SOx once accumulates in the circulation tank 6 at the bottom of the absorption tower 1 and is oxidized by oxygen in the air supplied from an air supply pipe (not shown) while being stirred by an oxidation stirrer (not shown). Calcium sulfate (gypsum) is produced. The absorbent is supplied from an absorbent slurry (mainly limestone slurry) supply line (not shown) according to the amount of SOx contained in the exhaust gas from the boiler or the like. A part of the slurry-like absorption liquid 5 in the circulation tank 6 in which calcium carbonate and gypsum coexist is pressurized by the absorption liquid circulation pump 4, and the upper spray header in the absorption tower 1 is passed through the absorption liquid circulation pipe 8. 9 and a part thereof is sent to a waste liquid treatment / gypsum recovery system (not shown) from an absorption liquid extraction pipe (not shown).

  Further, among the absorbing liquid 5 atomized by the spray from the spray nozzle 10, those having a small droplet diameter are accompanied by the exhaust gas, but are collected by the mist eliminator 7 provided on the outlet duct 3 side.

  In this prior art, as shown in FIG. 9, a pipe structure is branched from the absorption liquid circulation pipe 8 to a plurality of spray headers 9 and inserted into and penetrates the absorption tower 1 outside the absorption tower 1. In the case of this structure, since it is necessary to make holes corresponding to the number of the spray headers 9 through the side walls of the absorption tower 1 to penetrate the spray headers 9, a plurality of holes are provided at each stage, that is, in the case of a plurality of stages, many holes are made. It will be. Therefore, there is a problem that the number of manufacturing steps increases and the equipment cost tends to increase.

In addition, the spray nozzle 10 of the absorption tower 1 is often a holocon nozzle, but due to the relationship between the characteristics of the hollow hollow cone nozzle and the superposition of spray droplets between the spray nozzles 10, There is a problem that a dead zone occurs and gas blow-through occurs.
Regarding the problem of this gas blow-off phenomenon, in Patent Document 1 below, the spray nozzles are arranged in a staggered manner when viewed from above, so that the dead zone of the holocon nozzle is not generated.

  On the other hand, in the vicinity of the inner wall of the absorption tower 1, there also arises a problem that the amount of falling liquid is smaller than that at the center. This is because, in the central portion of the absorption tower 1, the spray droplets of the absorbing liquid 5 gather from all directions of the absorption portion where the spray header 9 is arranged, whereas in the inner wall portion, the spray droplets from the inner direction of the tower. This is because the spray droplets do not scatter from the outside of the tower although they collect. Accordingly, a large amount of exhaust gas tends to flow on the inner wall portion of the absorption tower 1, causing a gas blow-out phenomenon and causing a decrease in desulfurization performance.

In order to cover such a decrease in the desulfurization performance, it is necessary to spray a larger amount of the absorbent 5, which not only increases the power of the absorbent circulating pump 4 but also increases the pressure loss of the absorber. This leads to an increase in power of a desulfurization fan (not shown).
Therefore, it is necessary to consider the blow-by of gas in the vicinity of the inner wall of the absorption tower 1.

  Regarding the problem of the gas blow-off phenomenon at the inner wall of the absorption tower, the ring-type spray header is shown in Patent Document 2 below, although the purpose and effect thereof are different. Since the plan view of the absorption tower is not shown, the detailed structure is unknown, but this ring-shaped spray header is disposed in the vicinity of the inner wall of the absorption tower to prevent gas blow-through.

JP-A-63-151337 Japanese Patent Laid-Open No. 11-239715

  According to the configuration of Patent Document 1 below, the arrangement of spray headers at each stage is devised so that a dead zone of the hollow cone nozzle does not occur. However, since the droplets are not easily scattered near the inner wall of the absorption tower 1, it is dead. A zone is likely to be generated, and the amount of falling liquid is less than that in the center. And in patent document 1, the internal branching system of the spray header is adopted, and the spray header (main spray header) penetrating the absorption tower is taken as one, and in the direction perpendicular to the main spray header inside the absorption tower after penetration. A plurality of sub spray headers (headers branching from the main spray header) are provided.

  Since there is only one penetration part to the absorption tower of the main spray header in each stage, the equipment cost can be suppressed. However, in the case of this internal branching system, a thick main spray header before branching is present in the central portion of the absorption tower, so that the gas flow in the central portion is hindered and gas drift tends to occur. Originally, many spray droplets fall in the central part of the absorption tower, so it is rather necessary to introduce a lot of gas accordingly. However, in the configuration of Patent Document 1, the main spray header arranged in the central part of the tower is used. On the contrary, the presence of the gas makes it difficult for the gas to flow into the center of the absorption tower.

  Moreover, according to the structure of following patent document 2, it is estimated that it becomes possible to prevent the blow-by of the gas in the vicinity of the inner wall of an absorption tower. However, if the spray header is formed in a ring shape, the absorbing liquid cannot be sprayed on the central portion of the absorption tower, and conversely, gas drift to the central portion of the tower is induced. Further, in Patent Document 2, only one stage of the spray header is shown. However, when this ring-shaped spray header is formed in a plurality of stages, it is impossible to provide directionality at the time of installation. Since the spray headers overlap each other), it is not desirable for gas mixing because it has the same structure at every stage. Therefore, once a high-concentration SOx region is formed, the high-concentration SOx region flows to the outlet and is discharged.

  From the above, in the above-mentioned prior art, sufficient consideration is not given to the number of manufacturing steps of the absorption tower, the gas drift in the absorption tower, and the gas blow-off in the vicinity of the inner wall of the absorption tower, and the equipment cost tends to increase. Further, there is a problem that the power of the absorbing liquid circulation pump and the desulfurizing fan increases when the amount of the absorbing liquid circulating is increased in order to compensate for the deterioration of the desulfurizing performance due to gas drift and gas blow-off.

  An object of the present invention is to provide a wet flue gas desulfurization apparatus that has high desulfurization performance by preventing gas blow-out and gas drift without significantly increasing facility costs and power.

  The problem of the present invention is that the circulation pipe connected to the spray header of each stage is made into a single pipe and penetrates the absorption tower from a single place on the side wall of the absorption tower into the absorption tower, and the circulation pipe is extended along the inner wall of the absorption tower. This is achieved by connecting to a substantially central portion of the main spray header to be arranged and branching from the main spray header to a plurality of sub spray headers extending in the same direction as the circulation pipe.

Moreover, you may change the penetration direction into the absorption tower of circulation piping for every spray header of each stage.
Further, a circulation pipe connected to the main spray header located at the lowest stage on the most upstream side of the gas flow may be inserted and penetrated into the absorption tower from the upper side wall of the exhaust gas inlet portion.
Further, a spray nozzle may be provided at the bottom of the main spray header.

Specifically, the object of the present invention can be achieved by adopting the following configuration.
The invention described in claim 1 includes an inlet portion that introduces exhaust gas discharged from a combustion device including a boiler in a substantially horizontal direction, and the exhaust gas that is introduced from the inlet portion and rises above the inlet portion. An absorption part having a spray nozzle for spraying an absorption liquid that absorbs sulfur oxide therein, a storage part for storing the absorption liquid sprayed from the spray nozzle, and a circulation part for circulating the absorption liquid in the storage part to the absorption part; In the wet flue gas desulfurization apparatus provided with an absorption tower provided with an outlet for discharging exhaust gas that has passed through the absorption part, the absorption part is provided with a plurality of spray headers provided with a plurality of spray nozzles in the vertical direction, and a circulation part Each of which has a circulation pipe for sending the absorption liquid in the reservoir to the spray header, and each circulation pipe penetrates into the absorption tower from a single location on the side wall of the absorption tower, and the spray header of each stage. The spray headers of each stage are connected to the circulation pipe, the main spray header extending along the circumferential direction of the inner wall of the absorption tower, and the branch sprayed from the main spray header. It is a wet type flue gas desulfurization device provided with a plurality of sub-spray headers extending in the same direction as the pipe penetration direction.

Invention of Claim 2 is a wet flue gas desulfurization apparatus of Claim 1 from which the penetration direction with respect to the absorption tower of each said circulation piping differs for every spray header of each stage.
According to a third aspect of the present invention, there is provided the wet flue gas desulfurization apparatus according to the first or second aspect, wherein the circulation pipe connected to the lowermost spray header penetrates from the side wall at the upper part of the inlet of the absorption tower into the absorption tower. It is.
The invention according to claim 4 is the wet flue gas desulfurization apparatus according to any one of claims 1 to 3, wherein a spray nozzle is provided at a bottom portion of the main spray header.

(Function)
In the above-described conventional technology, there are problems such as an increase in the number of manufacturing steps of the absorption tower, gas drift in the absorption tower and gas blow-out, and the gas mixing in the absorption tower has not been sufficiently considered.

  Regarding these points, according to the first aspect of the invention, the spray header of each stage adopts the internal branching system, and has only one through portion with respect to the side surface of the absorption tower of the circulation pipe. Conventionally, as shown in FIG. 9, it is necessary to open a plurality of holes for each spray header in each stage, and in the case of a plurality of stages, many holes are formed in the side wall of the absorption tower. However, according to the present invention, the number of man-hours for production can be reduced by providing one through portion for each side of the absorption tower.

  Moreover, the main spray header is arrange | positioned inside an absorption tower by employ | adopting the internal branch system which the spray header of each stage branches in the inside of an absorption tower. In this case, since the circulation pipe is connected to the substantially central portion of the main spray header, the main spray header is branched and absorbed immediately after the piping structure moves to the main spray header across the side wall of the absorption tower. Since the liquid flow is structured in two directions, it is possible to send the absorbing liquid evenly in both directions and to make the main spray header 70% or less in diameter.

  Furthermore, the main spray header is disposed along the circumferential direction of the inner wall of the absorption tower, and a thick main spray header is not disposed at the center of the absorption tower as in Patent Document 1. Originally, many spray droplets fall in the central part of the absorption tower, so it is necessary to introduce a lot of gas accordingly. In this invention, since the main spray header is not arrange | positioned in the center part of an absorption tower, the gas flow which rises is not inhibited.

  Further, by disposing the main spray header in the vicinity of the inner wall of the absorption tower in this way, the presence of the main spray header suppresses gas blow-off in the vicinity of the inner wall.

  The gas blow-off in the vicinity of the inner wall can achieve the same effect even in the case of a ring-shaped spray header as in Patent Document 2, but normally, since the spray header is composed of a plurality of stages with respect to the gas flow, the ring-shaped When the spray header is made up of a plurality of stages, the directionality cannot be given at the time of installation, and all stages have the same structure, and the effect on gas mixing cannot be expected so much.

  However, according to the invention described in claim 2, in addition to the action of the invention described in claim 1, the penetration direction (insertion direction) of the circulation pipe into the absorption tower is changed for each spray header. Therefore, the portion that blocks the gas flow is different for each spray header of each stage. That is, since the sub spray header extends in the same direction as the penetration direction of the circulation pipe of each stage, the arrangement of the sub spray header differs at each stage. Also, the arrangement of the main spray headers at each stage connected to the circulation pipes at each stage is different.

  Therefore, the gas goes up in the absorption tower while detouring (the gas goes up in a zigzag manner), and a gas mixing effect can be obtained. In this case, even if a high-concentration SOx region is created, desulfurization is performed while the absorber is raised, and the concentration is lowered, so that SOx is prevented from being discharged at a high concentration.

  In addition, in order to avoid absorption liquid that falls a lot in the center of the absorption tower, a part of the exhaust gas introduced from the inlet duct immediately passes toward the absorption section after passing through the absorption tower entrance (opening). It becomes easy to rise. Therefore, in the spray nozzle at the lowermost stage where the gas flow is the uppermost stream side, a high flow velocity region is formed on the inlet side, which causes desulfurization performance to deteriorate.

  On the other hand, according to the invention described in claim 3, in addition to the operation of the invention described in claim 1 or 2, the circulation pipe is inserted into the absorption tower from the upper side wall of the exhaust gas inlet. The presence of the main spray header arranged along the inner wall of the absorption tower by connecting to the spray header located on the uppermost stream side of the gas flow, that is, the lowermost stage, serves as a shield against the high flow velocity region near the inlet. Therefore, a decrease in desulfurization performance can be prevented.

  According to the invention described in claim 4, in addition to the operation of the invention described in any one of claims 1 to 3, by installing a spray nozzle at the bottom of the main spray header, Since the absorption liquid can be sufficiently sprayed even with respect to the gas flowing in the vicinity of the main spray header, it is possible to prevent the desulfurization performance from being deteriorated due to the gas passing through the gap between the main spray header and the absorption tower inner wall.

  According to the present invention, it is possible to reduce the number of manufacturing steps of the absorption tower by adopting an internal branching system in which the spray header branches inside the absorption tower, and the main spray header is arranged along the vicinity of the inner wall of the absorption tower. The gas blow-off in the vicinity of the inner wall can be suppressed. Therefore, there are effects such as reduction of equipment cost and improvement of desulfurization performance.

  That is, according to the first aspect of the present invention, the number of manufacturing steps of the absorption tower can be reduced, and the gas blow-off in the vicinity of the inner wall can be suppressed without inhibiting the gas flow in the central portion of the absorption tower.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1 above, the arrangement of the spray headers at each stage causes the gas to rise in the absorption tower while detouring, so that the gas The mixing effect can be obtained and the desulfurization performance can be further improved.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, the lowermost spray header serves as a shield against the high flow velocity region near the exhaust gas inlet. Therefore, a decrease in desulfurization performance can be prevented.

  Further, according to the invention described in claim 4, in addition to the effect of the invention described in any one of claims 1 to 3, the absorbing liquid is also applied to the gas flowing in the vicinity of the main spray header. By spraying, it is possible to prevent a decrease in desulfurization performance due to slipping of gas flowing through the gap between the main spray header and the inner wall of the absorption tower.

It is a side view of the absorption tower of the wet flue gas desulfurization apparatus which is one Example of this invention. It is an A-A 'line arrow directional view of FIG. FIG. 3 is an arrow view between A-A ′ and B-B ′ in FIG. 1. FIG. 2 is an arrow view between B-B ′ and C-C ′ in FIG. 1. FIG. 2 is an arrow view between C-C ′ and D-D ′ in FIG. 1. FIG. 2 is an arrow view between A-A ′ and D-D ′ in FIG. 1. It is a side view of the absorption tower of the wet flue gas desulfurization apparatus which is another Example of this invention. It is a side view of the absorption tower of the wet flue gas desulfurization apparatus of a prior art. It is the top view which showed the structure of the spray header in FIG.

  Embodiments of the present invention are shown below.

  In FIG. 1, the side view of the absorption tower 1 of the wet flue gas desulfurization apparatus which is one Example of this invention is shown (the inside is also shown). Moreover, in FIGS. 2-5, the plane arrow line view for every spray header of each step | level of the absorption tower in FIG. 1 is shown. That is, FIG. 2 shows a plan view of the vicinity of the lowermost spray header 9, FIG. 3 shows a plan view of the vicinity of the second-stage spray header 9, and FIG. 4 shows a vicinity of the second-stage spray header 9. FIG. 5 shows a plan view of the vicinity of the uppermost spray header 9. FIG. 6 is a plan view showing the arrangement relationship of all the spray headers 9.

  This wet flue gas desulfurization apparatus is mainly composed of an absorption tower 1, an inlet duct 2 for introducing exhaust gas into the absorption tower 1, an outlet duct 3 from which exhaust gas is discharged, and a plurality of stages in the vertical direction along the flow direction of the exhaust gas. A spray header 9 provided with a number of spray nozzles 10 for spraying the absorbing liquid 5 on the exhaust gas from the inlet duct 2, a circulation tank 6 for storing the absorbing liquid sprayed from the spray nozzle 10, and an absorbing liquid in the circulation tank 6 Absorption liquid circulation pipe 8 for circulating the liquid to spray header 9, liquid absorption liquid circulation pump 4 provided in absorption liquid circulation pipe 8, and mist for removing minute droplets accompanying the flow of exhaust gas Consists of eliminator 7 and the like.

  Exhaust gas containing sulfur oxides discharged from a combustion apparatus such as a boiler installed in a thermal power plant or factory, etc. is sent from the inlet duct 2 to the absorption tower inlet 13 in the direction of the arrow X (substantially horizontal direction) by a desulfurization fan (not shown). ) And is introduced into the absorption tower 1, then rises, passes through the absorption tower outlet 14 provided at the top of the absorption tower 1, and is discharged from the outlet duct 3 in the direction of arrow Y. During this time, the absorbent 5 containing an absorbent such as limestone or lime-containing slurry sent from the absorbent circulating pump 4 is sprayed from a plurality of spray nozzles 10 attached to the spray header 9. By bringing the absorbent droplet sprayed as fine droplets from the spray nozzle 10 into contact with the exhaust gas, the SOx in the exhaust gas is absorbed by the spray nozzle 10 together with the soot and the acidic gas such as HCl and HF in the exhaust gas. It is absorbed and removed chemically at the surface.

  The absorbent 5 that has absorbed SOx once accumulates in the circulation tank 6 at the bottom of the absorption tower 1 and is oxidized by oxygen in the air supplied from an air supply pipe (not shown) while being stirred by an oxidation stirrer (not shown). Produces gypsum. The absorbent is supplied from an absorbent slurry (mainly limestone slurry) supply line (not shown) according to the amount of SOx contained in the exhaust gas from the boiler or the like. A part of the slurry-like absorption liquid 5 in the circulation tank 6 in which calcium carbonate and gypsum coexist is pressurized by the absorption liquid circulation pump 4, and passes through the absorption liquid circulation pipe 11 to be an upper spray header in the absorption tower 1. 9 and a part thereof is sent to a waste liquid treatment / gypsum recovery system (not shown) from an absorption liquid extraction pipe (not shown).

  Further, among the absorbing liquid 5 atomized by the spray from the spray nozzle 10, those having a small droplet diameter are accompanied by the exhaust gas, but are collected by the mist eliminator 7 provided on the outlet duct 3 side.

  In the embodiment shown in FIG. 1 to FIG. 6, the absorption liquid circulation pipe 8 connected to the spray header 9 at each stage in the absorption tower 1 is not branched outside the absorption tower 1, and one absorption tower 1 is left as it is. The absorption liquid circulation pipe 8 is connected to the substantially central portion of the main spray header 11 arranged along the inner wall of the absorption tower 1, and the same as the absorption liquid circulation pipe 8 from the main spray header 11. A plurality of sub-spread headers 12 extending in the direction are branched. The sub spray header 12 has a smaller diameter than the main spray header 11.

  Since the absorbing liquid circulation pipe 8 is connected to the substantially central portion of the main spray header 11, the absorbing liquid can be sent evenly in two directions branched from the central portion, that is, to both ends of the main spray header 11. In addition, since the sub spray header 12 extends from the main spray header 11 in the same direction as the absorption liquid circulation pipe 8, the sub spray header 12 smoothly flows without much change in the flow direction of the absorption liquid from the absorption liquid circulation pipe 8. Therefore, the power of the absorption liquid circulation pump 4 can be reduced.

  As described above, in this embodiment, the internal branching system of the spray header 9 is adopted, and there is only one through portion with respect to the side wall of the absorption tower 1 of the absorbent circulation pipe 8 connected to the main spray header 11 of each stage. It is. This makes it possible to reduce the number of manufacturing steps for the absorption tower.

  In addition, the main spray header 11 is arranged inside the absorption tower 1 by adopting the internal branching system in this way, but the piping structure is sandwiched between the absorption liquid circulation pipe 8 and the side wall of the absorption tower 1. Since the main spray header 11 is branched immediately after shifting to the spray header 11 and the flow of the absorbing liquid is in two directions, the main spray header 11 has a diameter of 70% or less than the conventional diameter. Yes.

  By reducing the diameter of the main spray header 11, it is possible to prevent the presence of the main spray header 11 from becoming an obstruction factor for the gas flow, and the influence on the gas flow can be reduced. Furthermore, if the sub spray header 12 is structured to be joined by a plurality of members so that the diameter becomes narrower toward the tip, the diameter can be gradually reduced in the order of the main spray header 11 and the sub spray header 12. .

In particular, since many spray droplets from the spray nozzle 10 fall in the center of the absorption tower 1, it is necessary to introduce a large amount of gas accordingly. In this embodiment, the main spray header 11 is used as the absorption tower. Since it arrange | positions along the inner wall vicinity of 1, it does not inhibit the gas flow to a tower center part.
Further, since the main spray header 11 is arranged along the vicinity of the inner wall of the absorption tower 1, the presence of the main spray header 11 suppresses gas blow-off in the vicinity of the inner wall.

  Usually, the spray header 9 is composed of a plurality of stages with respect to the gas flow. In a configuration in which a ring-shaped spray header is provided on the entire inner wall as in a conventional absorption tower, even if multiple spray headers are installed, they overlap completely when viewed from above, and all parts in the radial direction have the same gas. Therefore, it can be said that there is almost no gas mixing effect in the radial direction. However, according to this configuration, due to the presence of the plurality of sub spray headers 12 branched from the main spray header 11, gas mixing effects not only in the vertical direction but also in the radial direction can be obtained.

  Moreover, as shown in FIGS. 2-6, you may change the insertion direction of the absorption liquid circulation piping 8 to the absorption tower 1 for every stage. If it does in this way, the part in which the main spray header 11 and the sub spray header 12 block | interrupt a gas flow will differ for every stage, and the mixing effect of gas will increase further. Therefore, even if a high-concentration SOx region is formed, desulfurization is performed while rising in the absorption tower 1 to lower the concentration, so that SOx is prevented from being discharged at a high concentration.

  In the illustrated example, the spray headers 9 are arranged in four stages up and down, but may be smaller or larger than this. In the illustrated example, the absorption liquid circulation pipes 8 at each stage are provided at equal intervals in plan view, and the insertion direction of the absorption liquid circulation pipe 8 at each stage is also changed by the same angle (90 degrees in the illustrated example). However, it is not necessarily limited to this configuration. However, the main spray header 11 and the sub spray header 12 are arranged in a balanced manner by arranging the absorbing liquid circulation pipes 8 at each stage in a well-balanced manner, so that they are biased to the exhaust gas passing through any region in the absorption tower 1. Absorbing liquid is sprayed.

  When the absorbent flows from the main spray header 11 to the sub spray header 12, if there are many orthogonal portions at the bent portion of the pipe, pressure loss occurs, leading to an increase in power of the absorbent circulation pump 4. Therefore, as shown in FIG. 2 and the like, the branching portion from the main spray header 11 to the sub spray header 12 is rounded to have a curved surface, so that the flow of the absorbing liquid becomes smooth and the increase in pressure loss can be prevented. . The angle formed by the sub spray header 12 and the main spray header 11 is not 90 degrees, and the angle formed by the main spray header 11 and the sub spray header 12 on the upstream side of the branching portion is an obtuse angle. A part may be formed.

  In addition, a part of the exhaust gas introduced from the inlet duct 2 immediately passes through the inlet (opening) 13 of the absorption tower 1 so as to avoid the absorption liquid 5 that frequently falls in the center of the absorption tower 1. It becomes easy to raise toward the absorption part in which the multi-stage spray header 9 is installed. Therefore, in the vicinity of the lowermost spray header 9 located on the most upstream side of the exhaust gas flow, a high flow velocity region is formed on the inlet 13 or the inlet duct 2 side, which causes a decrease in desulfurization performance.

  On the other hand, according to the present embodiment, the inlet liquid 13 is inserted into the absorption tower 1 from the inlet duct 2 side with respect to the lowermost main spray header 11 and sub spray header 12, thereby allowing the inlet 13. Since the main spray header 11 is located on the upper portion of the absorber and is disposed along the inner wall of the absorption tower 1, the presence of the main spray header 11 serves as a shield against the high flow velocity region, and can prevent a decrease in desulfurization performance. . Accordingly, there is no need to increase the circulation amount of the absorbent 5, and there is also an effect of reducing power such as the absorbent circulation pump 4 and the desulfurization fan.

Moreover, in FIG. 7, the side view of the absorption tower 1 of the wet flue gas desulfurization apparatus which is another Example of this invention is shown.
In this figure, the example which installed the spray nozzle 10 also in the bottom part of the main spray header 11 of the absorption tower 1 of the wet flue gas desulfurization apparatus shown in FIG. 1 is shown. In addition, since it is the same as that of Example 1 except that, description is abbreviate | omitted. In FIG. 7, the spray nozzle 10 of the sub-spray header 12 is not shown for easy viewing, but actually, the spray nozzle 10 is also provided in the sub-spray header 12 as in FIG.

Since the spray nozzle 10 is provided not only at the sub spray header 12 but also at the bottom of the main spray header 11, the absorbent 5 can be sufficiently sprayed against the exhaust gas flowing in the vicinity of the main spray header 11. It is possible to prevent performance degradation due to gas passing through the gap between the spray header 11 and the inner wall of the absorption tower 1.
Also in this embodiment, the same operational effects as those of the first embodiment are obtained.

  The present invention is not limited to wet flue gas desulfurization devices, and may be used for other wet flue gas exhaust devices.

DESCRIPTION OF SYMBOLS 1 Absorption tower 2 Inlet duct 3 Outlet duct 4 Circulation pump 5 Absorption liquid 6 Circulation tank 7 Mist eliminator 8 Circulation piping 9 Spray header 10 Spray nozzle 11 Main spray header 12 Sub spray header 13 Absorption tower inlet 14 Absorption tower exit

Claims (4)

Absorbs the sulfur oxides in the exhaust gas into the inlet portion that introduces the exhaust gas discharged from the combustion device including the boiler in a substantially horizontal direction, and the exhaust gas that is introduced from the inlet portion and rises above the inlet portion. An absorption part having a spray nozzle for spraying an absorption liquid, a storage part for storing the absorption liquid sprayed from the spray nozzle, a circulation part for circulating the absorption liquid in the storage part to the absorption part, and an exhaust gas that has passed through the absorption part In the wet flue gas desulfurization apparatus provided with an absorption tower having an outlet for discharging
The absorption part is provided with a plurality of spray headers provided with a plurality of spray nozzles in the vertical direction,
The circulation section is equipped with circulation piping for sending the absorbing liquid in the storage section to the spray header for each stage spray header,
Each circulation pipe is a single pipe that penetrates into the absorption tower from a single location on the side wall of the absorption tower and connects to the spray header of each stage,
The spray headers of the respective stages are connected to the circulation pipe at a substantially central portion and extend along the circumferential direction of the inner wall of the absorption tower, and branch from the main spray header in the same direction as the penetration direction of the circulation pipe. A wet flue gas desulfurization apparatus comprising a plurality of sub spray headers extending.   The wet flue gas desulfurization apparatus according to claim 1, wherein a penetration direction of each circulation pipe with respect to an absorption tower is different for each stage of the spray header.   The wet flue gas desulfurization apparatus according to claim 1 or 2, wherein the circulation pipe connected to the lowermost spray header passes through the absorption tower from the side wall at the upper part of the inlet of the absorption tower.   The wet flue gas desulfurization apparatus according to any one of claims 1 to 3, wherein a spray nozzle is provided at a bottom portion of the main spray header.

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