JP5682045B1 - Wet flue gas desulfurization equipment - Google Patents

Abstract

To provide a wet flue gas desulfurization apparatus having an absorption tower inlet flue structure capable of preventing scaling in the absorption tower inlet flue. In order to prevent scaling in the exhaust gas inlet flue 3, in order to prevent the exhaust gas flow velocity at both ends of the exhaust gas inlet flue bottom surface 28 from becoming low, the bottom surface 28 of the exhaust gas inlet flue 3 is It forms in the convex shape which has the inclined surfaces 25 and 29 descend | falling toward both sides from a center, and also it is toward the bottom face 28 along the inclined surface 25 at the vertex 26 of the convex part at the bottom face of the entrance flue 3 (a). And / or (b) a rinsing device 23 for injecting rinsing water from the inlet flue toward the inside of the absorption tower on both side wall portions of the bottom surface 28 along the inclined surface 25. Is provided. [Selection] Figure 3

Description

  The present invention relates to a wet limestone-gypsum flue gas desulfurization apparatus, and more particularly to a wet flue gas desulfurization apparatus flue that prevents scaling in an absorption tower inlet flue and can easily cope with the occurrence of scaling. The present invention relates to a scaling prevention device.

In order to prevent air pollution, a wet limestone-gypsum flue gas desulfurization apparatus has been widely put into practical use as a sulfur oxide removal apparatus in combustion exhaust gas. The system of this desulfurization apparatus is shown in FIG.
In the desulfurization apparatus shown in FIG. 10, exhaust gas 1 from a boiler or the like is introduced into an absorption tower 104 from an inlet flue 103 having an inclined portion 102 and branched from spray headers 105 installed in multiple stages in the gas flow direction in the absorption tower 104. In contact with the droplets of the absorbing liquid sprayed from a large number of spray nozzles 107 provided in each header 106, soot, hydrogen chloride (HCl), acid gas such as hydrogen fluoride (HF) in the exhaust gas 1 At the same time, the sulfur oxide in the exhaust gas 1 is absorbed on the droplet surface.

  A limestone slurry 109 which is a sulfur oxide absorbent is stored in the limestone slurry tank 108, and the limestone slurry 109 is absorbed by the limestone slurry pump 110 according to the amount of sulfur oxide absorbed in the absorption tower 104. It is supplied to the liquid storage part 111 at the lower part in the tower 104.

  The slurry-like absorption liquid in the liquid storage section 111 in the absorption tower 104 is boosted by the absorption tower circulation pump 112 and provided in the upper empty tower section in the absorption tower 104 via the circulation pipe 113 in the gas flow direction. It is supplied to the spray header 105 provided in multiple stages. Each spray header 106 is provided with a number of spray nozzles 107, and the absorbing liquid is sprayed from the spray nozzles 107 to come into gas-liquid contact with the exhaust gas 1. The sulfur oxide in the exhaust gas reacts with the water in the absorption liquid to become sulfurous acid as an intermediate product, and falls into the liquid storage part 111 of the absorption tower 104.

  Sulfurous acid in the liquid storage unit 111 is oxidized by the air supplied from the oxidizing air blower 114 into the absorption liquid in the absorption tower 104 to become sulfuric acid, and then reacts with the calcium compound in the absorption liquid to produce a final product. (Gypsum). The exhaust gas in which the sulfur oxide has moved to the absorption liquid side rises in the absorption tower 104 and is discharged from the absorption tower outlet 115.

  In the configuration of the conventional desulfurization apparatus described above, when the exhaust gas 1 is introduced from the inlet flue 103 into the absorption tower 104, the droplets of the absorbing liquid sprayed from the spray nozzle 107 in the absorption tower 104 enter the inlet flue 103. And infiltrate. The calcium compound in the absorption liquid that has entered the inlet flue 103 adheres to the bottom surface of the inlet flue 103 and comes into contact with the sulfur oxide in the exhaust gas 1 to form a gypsum scale. The generated gypsum scale is dried by the exhaust gas 1, and the absorbing liquid adheres again on the dried gypsum scale. By repeating this process, scaling on the inlet flue 103 proceeds. When scaling progresses in this way, the gypsum scale blocks the exhaust gas flow path of the inlet flue 103, so that the pressure loss in the inlet flue 103 increases, and the exhaust gas 1 from the inlet flue 103 to the absorption tower 104 increases. This leads to a problem that the power of the fan for feeding the air increases.

  As means for preventing scaling by exhaust gas, there is one described in Japanese Utility Model Laid-Open No. 1-114026. This is because desulfurization absorption is performed to prevent the sulfur oxide contained in the gas introduced into the absorption tower from reacting with the absorption liquid flowing down along the side wall of the absorption tower at the exhaust pipe connection and causing scaling. A cleaning nozzle for preventing infiltration of the absorbing solution is provided at the connection portion of the exhaust pipe provided on the side wall of the tower.

  In the above-described conventional configuration, the cleaning nozzle (not shown) is attached so that the cleaning water flows into the absorption tower 104 along the inclined portion 102 from the inlet flue 103 of the absorption tower 104 shown in FIG. Measures are taken to prevent 103 scaling. However, it has been reported that the actual machine generates scaling in the inlet flue 103 even when the cleaning nozzle is provided in the inlet flue 103.

Japanese Utility Model Publication No. 1-114026

The prior art has the following problems in preventing scaling due to exhaust gas in the inlet flue of the absorption tower.
When exhaust gas is introduced from the inlet flue to the absorption tower, the droplets of the absorbing liquid sprayed from the spray nozzle in the absorption tower enter the inlet flue, and the calcium compounds in the absorbing liquid that has entered the inlet smoke A gypsum scale is produced by adhering to the bottom of the road and coming into contact with sulfur oxides in the exhaust gas.

  In the conventional inlet flue structure, the exhaust gas entering the absorption tower from the inlet flue rises in the absorption tower, so the exhaust gas flows to a position higher than the bottom at the connection part between the inlet flue and the absorption tower. The gas flow rate at the bottom of the inlet flue is low. Therefore, it has a structure in which the absorbing liquid that causes the gypsum scale easily adheres to the bottom surface of the inlet flue.

  In addition, when the exhaust gas enters the absorption tower from the inlet flue, the width of the absorption tower is wider than that of the inlet flue, so that part of the exhaust gas flow flows from both ends of the inlet flue. Take. As a result, the gas flow rate at the bottom of the inlet flue is particularly low at both ends of the inlet flue, and the absorbing liquid that causes the gypsum scale tends to adhere to both ends of the bottom of the inlet flue.

  Furthermore, when the absorbing liquid causing gypsum scale adheres to the bottom surface of the inlet flue, the adsorbed absorbing liquid can be washed from the cleaning nozzle only by providing a cleaning nozzle on the bottom surface with the conventional inlet flue structure. It cannot be washed away sufficiently by water. Depending on the power plant, there is an example in which scale accumulation of 1 m or more in height is confirmed from the bottom of the absorption tower entrance flue at the time of regular operation stoppage.

  An object of the present invention is to solve the above-described problems and to provide a wet flue gas desulfurization apparatus having an absorption tower inlet flue structure that can prevent scaling at the absorption tower inlet flue.

  In the present invention, the above-described scaling generation in the absorption tower inlet flue is solved by increasing the gas flow velocity at the bottom of the absorption tower inlet flue. As a method for increasing the gas flow rate, there is a means for reducing the cross-sectional area of the inlet flue with respect to the gas flow. However, when only the cross-sectional area is reduced in the conventional absorption tower inlet flue structure, the gas flow velocity at the bottom surface remains low compared to the portion above the bottom surface, and the anti-scaling effect is small. it is conceivable that. Further, reducing only the cross-sectional area in the conventional inlet flue structure changes the vertical and horizontal width of the inlet flue. At this time, the exhaust gas flow in the inlet flue changes greatly, and there is a possibility that the desulfurization performance may be changed.

  It is also necessary to increase the gas flow velocity at both ends of the inlet flue bottom. In order to increase the gas flow rate at both ends of the bottom surface of the inlet flue while maintaining the conventional inlet flue structure, a method of providing many rectifying plates from the inlet flue to the absorber tower can be considered, but the cost is high. There is a problem of becoming.

In the present invention, these problems are solved by making the bottom surface of the flue gas inlet flue of the absorption tower convex with an inclined surface descending from the center toward both sides. In addition, on the bottom of the entrance flue,
(1) Located at the apex of the convex portion and provided with a water washing device for injecting washing water along the inclined surface toward the bottom surface,
(2) A flushing device for injecting washing water from the inlet flue toward the inside of the absorption tower is provided at a portion connected to the inlet flue side wall on both sides of the bottom surface of the convex portion, or (3) the (1 ) And (2) are combined to solve the above-described problems of the present invention.

That is, the said subject of this invention is solved by the following solution means.
The invention according to claim 1 is an absorption unit that absorbs and removes dust, sulfur oxides, and substances resulting from components contained in fuel contained in exhaust gas discharged from a combustion apparatus, using an absorbent slurry, and the absorption A wet flue gas desulfurization apparatus comprising an absorption tower comprising a tank part for temporarily storing an absorbent slurry flowing down from the part,
A wet flue gas desulfurization apparatus characterized in that an inlet flue for the exhaust gas is provided on a side wall of the absorption tower, and a bottom surface of the inlet flue is formed in a convex shape having inclined surfaces descending from the center toward both sides. It is.

  The invention according to claim 2 is characterized in that the inclination angle of the inclined surface descending from the center of the bottom surface of the gas inlet flue toward both sides is 5 ° or more with respect to the horizontal plane. It is a flue gas desulfurization device.

  The invention according to claim 3 is a portion connected to the inlet flue side wall at the apex portion of the inclined surface formed in a convex shape on the bottom surface of the gas inlet flue and / or the both end portions of the inclined surface formed in a convex shape. The wet flue gas desulfurization apparatus according to claim 1 or 2, wherein a water washing apparatus is provided in the apparatus.

  According to a fourth aspect of the present invention, the water washing device installed at the apex portion of the inclined surface formed in a convex shape is a washing water injection device that injects cleaning water toward both ends of the bottom surface along the inclined surface. The wet flue gas desulfurization apparatus according to claim 3, wherein the wet flue gas desulfurization apparatus is provided.

  According to a fifth aspect of the present invention, there is provided the flushing device installed in a portion connected to the inlet flue side wall at both end portions of the inclined surface formed in a convex shape, with washing water from the gas inlet flue side toward the inside of the absorption tower. The wet flue gas desulfurization apparatus according to claim 3, wherein the apparatus is a washing water injection apparatus for injecting water.

  In the invention according to claim 6, a plurality of the flushing devices are installed from upstream to downstream of the gas inlet flue, and the washing water jetting power of each flushing device is sequentially increased from upstream to downstream of the gas inlet flue. The wet flue gas desulfurization device according to any one of claims 3 to 5, wherein the wet flue gas desulfurization device has an increased configuration.

  According to the first aspect of the present invention, the bottom surface of the gas inlet flue of the absorption tower is formed in a convex shape having an inclined surface that descends from the center toward both sides. Since it raises compared with the case where an inclined surface is not provided, adhesion of adsorbed liquid to the bottom surface and side wall surface of the gas inlet flue, which is a problem in the conventional gas inlet flue structure, can be suppressed.

  Further, the structure provided with the inclined surface of the gas inlet flue enables the absorbing liquid to be collected at both end portions of the gas inlet flue, so that it is more effective than the conventional inlet flue structure provided with a flush nozzle on the bottom surface. The absorption liquid can be dropped into the absorption tower.

  That is, according to the first aspect of the present invention, (1) the problem that the gas flow velocity at the bottom of the inlet flue is low, which causes the adhering of the absorbent, and (2) the bottom of the inlet flue, It is possible to simultaneously solve the problem that even if the water washing nozzle is provided, the adhering liquid that has adhered cannot be sufficiently washed away.

  Further, in the present invention according to claim 1, in the central portion of the inclined surface, the gas flow rate is increased by reducing the cross-sectional area of the flue while maintaining the structure of the conventional gas inlet flue. This has the effect of increasing the gas flow rate. Therefore, it is possible to solve the problem that the gas flow velocity at the bottom surface of the inlet flue is lower than that of the portion above the bottom surface and the scaling prevention effect is small, which is a problem with the conventional gas inlet flue structure.

  At the same time, the gas flow rate at the central portion of the inclined surface increases, making it difficult for the absorbing liquid to enter the gas inlet flue from the center of the gas inlet flue. As a result, the absorption liquid that has entered the gas inlet flue from the center of the gas inlet flue is less likely to scatter and adhere to both ends of the gas inlet flue to form a gypsum scale. That is, by increasing the gas flow rate at the central portion of the inclined surface, there is also an effect of preventing scaling at both ends of the bottom surface of the gas inlet flue where the gas flow rate is particularly low.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the inclined surface is not provided by setting the inclined angle of the inclined surface to 5 ° or more in the horizontal direction upward from below. Compared to the case, the gas flow rate on the inclined surface can be increased.

Further, even when the absorbing liquid enters the gas inlet flue and adheres to the bottom surface, the absorbing liquid can be collected at both ends of the gas inlet flue along the inclined surface of the bottom surface.
According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, the apex portion of the inclined surface and / or the convex shape formed in the convex shape of the bottom surface of the gas inlet flue. By providing a flushing device in the portion connected to the inlet flue side wall at both ends of the inclined surface, the washing water and the absorbing liquid can be easily collected at both ends of the gas inlet flue. The washing water and the absorption liquid collected at both end portions fall into the absorption tower by the gas whose flow velocity is increased on the inclined surface.

  According to the fourth aspect of the present invention, in addition to the effect of the third aspect of the invention, the cleaning water is provided at the apex portion of the inclined surface formed in a convex shape along the inclined surface of the bottom surface. By providing the cleaning water injection device that injects the cleaning water, the cleaning water and the absorbing liquid can be easily collected at both ends of the inlet flue while spraying the cleaning water toward both ends of the bottom surface. The washing water and the absorption liquid collected in the part fall into the absorption tower by the gas whose flow velocity is increased on the inclined surface.

  According to the fifth aspect of the invention, in addition to the effect of the third aspect of the invention, the gas inlet flue side is connected to the portion connected to the inlet flue side wall at both end portions of the inclined surface formed in a convex shape. By providing the cleaning water injection device for injecting the cleaning water toward the inside of the absorption tower, it becomes easy to drop the cleaning water and the absorbing liquid collected at both ends of the gas inlet flue into the absorption tower.

  In this way, in the gas inlet flue having the inclined surface, the bottom surface of the conventional inlet flue has a structure in which cleaning water and absorption liquid are collected at both end portions of the gas inlet flue and are collectively dropped into the absorption tower. As compared with the structure in which the cleaning nozzle is provided, the cleaning water and the absorbing liquid can be effectively dropped from the inlet flue into the absorption tower.

  In addition, since cleaning water is injected from the cleaning water injection device toward the inside of the absorption tower from the gas inlet flue side, it is not necessary to consider the conventional problem that the gas flow velocity is low at both ends of the bottom of the gas inlet flue. It is not necessary to take measures such as providing a current plate from the flue to the absorption tower.

  According to the invention of claim 6, in addition to the effect of the invention of any of claims 3 to 5, a plurality of the water washing devices are provided from upstream to downstream of the gas inlet flue, In this case, the cleaning water injection force is increased gradually from the upstream to the downstream of the gas inlet flue. The amount of water required to drop the adsorbed absorption liquid to the absorption tower side can be reduced by decreasing the washing water jetting force on the upstream side of the inlet flue far from the absorption tower.

1 is a system diagram of a wet limestone-gypsum flue gas desulfurization apparatus according to an embodiment of the present invention. The figure which looked at the center part side of an inlet flue part from the vertical direction cross-sectional direction in the position which removed the center part of the inlet flue part connected to the absorption tower of FIG. 1 (the AA line sectional arrow view of FIG. 3) It is. It is a cross-sectional view in the gas inlet side from the vertex of the convex inclined surface of the inlet flue part connected to the absorption tower of FIG. It is a perspective view of the entrance flue part connected to the absorption tower shown in FIG. FIG. 2 is a flow velocity distribution diagram in a cross section of an absorption tower inlet flue in the wet flue gas desulfurization apparatus of FIG. 1. It is a flow-velocity distribution figure in the cross section of the absorption tower entrance flue in the wet flue gas desulfurization apparatus of a prior art. It is the figure showing the flow rate increase rate with respect to the cross-section reduction rate in the cross section of the absorption tower entrance flue in the wet flue gas desulfurization apparatus of FIG. It is sectional drawing which looked at the absorption tower inlet flue and the absorption tower in the wet flue gas desulfurization apparatus which is another Example of this invention from the cross section of the inlet flue. It is sectional drawing which looked at the absorption tower inlet flue and the absorption tower in the wet flue gas desulfurization apparatus which is another Example of this invention from the cross section of the inlet flue. 1 is a system diagram of a wet limestone-gypsum flue gas desulfurization apparatus according to the prior art.

Embodiments of the present invention will be described with reference to the drawings.
The structure of the absorption tower inlet flue in the wet flue gas desulfurization apparatus of the present embodiment is shown in FIGS. FIG. 1 is a system diagram of a wet limestone-gypsum flue gas desulfurization apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram in a position where a central portion of an inlet flue portion connected to the absorption tower of FIG. 1 is removed. It is the figure which looked at the center part side of the entrance flue part from the vertical direction cross-sectional direction (the AA line cross-sectional view of FIG. 3). 3 is a cross-sectional view on the gas inlet side from the apex of the convex inclined surface of the inlet flue portion connected to the absorption tower of FIG. FIG. 4 is a perspective view of an inlet flue portion connected to the absorption tower shown in FIG.

  In the desulfurization apparatus shown in FIG. 1, exhaust gas 1 from a boiler or the like is introduced from an inlet flue 3 having an inclined portion 2 into an absorption tower 4 and branched from a spray header 5 installed in multiple stages in the gas flow direction in the absorption tower 4. In contact with the droplets of the absorbing liquid sprayed from a number of spray nozzles 7 provided on each header 6, soot gas in the exhaust gas 1, acidic gas such as hydrogen chloride (HCl), hydrogen fluoride (HF), etc. At the same time, the sulfur oxide in the exhaust gas 1 is absorbed on the droplet surface.

  The limestone slurry tank 8 stores a limestone slurry 9 that is an absorbent of sulfur oxide, and the limestone slurry 9 is absorbed by the limestone slurry pump 10 in accordance with the amount of sulfur oxide absorbed in the absorption tower 4. It is supplied to the liquid storage part 11 at the lower part in the tower 4.

  The slurry-like absorption liquid in the liquid storage section 11 in the absorption tower 4 is boosted by the absorption tower circulation pump 12 and provided in the upper empty tower section in the absorption tower 4 via the circulation pipe 13 in the gas flow direction. It is supplied to spray headers 5 provided in multiple stages. Each spray header 6 is provided with a number of spray nozzles 7, and the absorbing liquid is sprayed from the spray nozzles 7 to come into gas-liquid contact with the exhaust gas 1. The sulfur oxide in the exhaust gas reacts with the water in the absorption liquid to become sulfurous acid as an intermediate product, and falls into the liquid storage part 11 of the absorption tower 4.

  The sulfurous acid in the liquid storage unit 11 is oxidized by the air supplied from the oxidizing air blower 14 into the absorption liquid of the absorption tower 4 to become sulfuric acid, and then reacts with the calcium compound in the absorption liquid to produce a final product. (Gypsum). The exhaust gas in which the sulfur oxide has moved to the absorption liquid side rises in the absorption tower 4 and is discharged from the absorption tower outlet 15.

The absorption tower of the present embodiment is configured such that the exhaust gas 1 is introduced into the absorption tower 4 from the inlet flue 3 having the inclined wall surface 2 as in the conventional absorption tower shown in FIG.
In the present embodiment, a convex inclined surface 25 that descends from the center of the cross section of the inlet flue 3 toward both sides is provided on the bottom surface of the inlet flue 3 along the inclined wall surface 2. As shown in FIG. 3, the inclined surface 25 is provided at an inclination angle 27 with respect to the horizontal plane so that the inlet flue cross section is symmetric about the vertex 26 of the convex inclined surface 25. The absorbing liquid that has entered the inlet flue 3 from the absorption tower 4 flows down along the inclined surface 25 from the apex 26, is collected at both ends of the bottom face of the inlet flue, and falls into the absorption tower 4 by the exhaust gas 1.

  As shown in FIGS. 2 and 4, an inclined surface 29 is provided from the apex 26 of the inclined surface 25 to the bottom surface 28 on the upstream side of the inlet flue 3. The inclination angle of the inclined surface 29 with respect to the horizontal plane is the same as the inclination angle 27 of the inclined surface 25 with respect to the horizontal plane. The reason why the inclined surface 29 is provided is that the step represented by the phantom dotted line in FIG. 2 obstructs the gas flow between the apex 26 and the bottom surface 28 of the convex inclined surface 25 upstream of the inlet flue 3 only by providing the inclined surface 25. This is to prevent the appearance of a space where no gas flows in the inlet flue 3 upstream of the step 20.

  As shown in FIGS. 2 to 4, the water washing device 21 is provided at the apex 26 of the convex inclined surface 25. The water washing apparatus 21 sprays washing water from the apex 26 toward the both ends along the inclined surface 25 to prevent the absorption liquid from adhering to the inclined surface 25, and to absorb the absorbing liquid to both end portions of the inclined surface 25. It plays two roles. In FIG. 2 to FIG. 4, one washing device 21 is provided at the connecting portion between the inclined surface 25 and the inclined surface 29, but a plurality of water washing devices 21 may be provided on the inclined surface 25.

  As shown in FIGS. 2 to 4, the water washing device 23 extends from the bottom surface 28 on the upstream side of the inlet flue 3 to the connecting portion 22 between the inlet flue 3 and the absorption tower 4 at both ends of the inlet flue bottom surface 28. Is provided. The water washing device 23 injects the washing water from the inlet flue 3 toward the absorption tower 4, so that the absorption liquid collected at both ends by the inclined surface 25 and the water washing device 21 is sprayed together with the sprayed washing water in the absorption tower 4. Plays the role of dropping inside.

  A plurality of water washing devices 23 may be installed along the inclined surface 25. In FIG. 3, the water washing device 23 is provided only on a part of the inclined surface 25, but a plurality of water washing devices 23 may be installed along the connection portion with the inlet flue bottom surface 28. In that case, if scaling occurs, the washing water injection force of the water washing device 23 installed closer to the absorption tower 4 is increased, and the water washing device 23 installed on the inlet flue 3 side as viewed from the absorption tower 4 is washed. It is possible to reduce the required amount of water by reducing the water jetting power.

FIG. 5 shows a measurement result indicating that the gas flow velocity in the vicinity of the apex 26 of the inclined surface 25 in the gas inlet flue 3 of the present embodiment rises from both ends of the inclined surface 25.
FIG. 5 shows the apex 26 when the inclined surface 25 and the inclined surface 29 shown in FIG. 4 are provided in the inlet flue 3 of this embodiment, and the inclined angle of the inclined surface 25 and the inclined surface 29 with respect to the horizontal plane is 5 °. 2 shows the gas flow velocity in the vicinity of the apex 26 and the gas flow velocity at both ends of the inclined surface 25 in the vertical sectional view passing through. FIG. 6 shows the gas flow velocity at the center and the gas flow velocity at both ends in the vertical sectional view of the gas inlet flue 3 in the structure of the conventional gas inlet flue 3 where the inclined surfaces 25 and 29 are not installed. It is.

The gas flow velocity near the apex 26 of the convex inclined surface 25 of this embodiment shown in FIG. 5 is 13 to 14 m / s, and the gas flow velocity near both ends of the inlet flue bottom surface 28 is 10 to 12 m / s.
In the structure of the prior art flue 3 without the apex 26 of the convex inclined surface 25 shown in FIG. 6, the average gas flow velocity near the bottom surface 28 is 7 to 9 m / s, and at the center of the bottom surface 28 of the inlet flue 3. The flow velocity of is substantially equal compared to other regions.

  In FIG. 5, by installing an inclined surface having an inclination angle of 5 ° with respect to the horizontal surface of the inclined surfaces 25 and 29, the average gas flow velocity in the vicinity of the inclination corresponding to the bottom surface 28 of the inlet flue 3 becomes 10 to 12 m / s. The gas flow velocity in the vicinity of the inclined surfaces 25 and 29 increases.

  At this time, there is a difference between the gas flow velocity in the vicinity of the vertex 26 of the convex inclined surface 25 and the gas flow velocity in the vicinity of the bottom surface 28 at both ends of the inlet flue 3, and between the vicinity of the vertex 26 and both ends of the bottom surface 28. The gas flow velocity distribution occurs, and the effect of increasing the gas flow velocity in the vicinity of both ends of the bottom surface 28 is smaller than that in the vicinity of the apex 26, but the water washing shown in FIGS. Since the apparatus 23 is provided and the washing water flows in the direction toward the inside of the absorption tower, there is no need to consider the problem that the absorbing liquid adheres due to the relatively low gas flow rate.

Next, the optimum angle of the inclination angle 27 of the inclined surface 25 shown in FIG. 3 will be described.
FIG. 7 shows an example in which the inclined surfaces 25 and 29 similar to FIG. 4 are provided in the inlet flue 3 of the wet flue gas desulfurization apparatus, and the inclined angle 27 of the inclined surfaces 25 and 29 with respect to the horizontal plane is 2 ° to 20 °. When the cross-sectional area reduction rate at the inlet flue 3 when the distance is changed to the x-axis, the gas flow velocity near the vertex 26 (point b) in the vertical sectional view passing through the vertex 26 and both ends of the inclined surface 25 (point a) , C) is the y-axis of the gas flow rate increase rate.

First, the points ac shown in the three-dimensional coordinates having the xyz axes in FIG. 5 will be described.
The x-axis is the direction from the central part of the inlet flue 3 to the central part of the absorption tower 4, the y-axis is the direction perpendicular to the x-axis, and both ends of the inlet flue 3 are connected on the parallel line of the y-axis. Is done. The z-axis is the height direction of the inlet flue 3. The distance in the y-axis direction between adjacent points a and b, and points b and c shown in FIG. 5 is constant, and points a, b, and c are all on the inclined surface 25, and points a and b The point c is located at both end portions of the inclined surface 25, and the point b is located at the vertex 26 of the inclined surface 25. In FIG. 6, the points a ′, b ′, and c ′ that are not provided with the inclined surfaces 25 and 29 are all present on the bottom surface 28 of the inlet flue 3 and have the same height in the z-axis direction. The points a ′ and c ′ are located at both end portions of the bottom surface 28 of the inlet flue 3 and are located symmetrically about the point b ′.

  In the present embodiment, by providing the inclined surfaces 25 and 29, gas cannot pass through portions below the inclined surfaces 25 and 29 in the inlet flue 3, so that the cross-sectional area of the inlet flue 3 is reduced. The amount of reduction expressed as a ratio (%) to the cross-sectional area of the inlet flue 3 is the cross-sectional area reduction rate, which corresponds to the horizontal axis of FIG.

The gas flow rate increase rate shown on the vertical axis in FIG. 7 indicates the flow rate increase rate at points a to c in FIG. 5 with reference to the flow rates at points a ′ to c ′ in FIG. 6. The following are the expressions.
(Aa ') / a', (bb ') / b', (cc ') / c'

  A straight line S shown in FIG. 7 indicates the average gas flow velocity in the inlet flue 3. The average gas flow rate increases in proportion to the cross-sectional area reduction rate. That is, FIG. 7 shows that a certain cross-sectional area reduction rate can be expected to have a scaling prevention effect because a flow velocity increase equal to or higher than the average gas flow velocity increase rate is obtained at a point located above the straight line S.

As for the inclination angle 27, the measurement results in the case of 2 °, 5 °, 10 °, and 20 ° are shown by elliptical dotted lines.
Regardless of the magnitude of the inclination angle 27, the gas flow velocity at both ends of the inlet flue 3 is substantially the same as the average gas flow velocity, and the gas flow velocity increase effect at the both ends depends on the inclination angle 27 of the inclined surfaces 25 and 29. The difference cannot be confirmed. When the inclination angle 27 is less than 5 °, both the central portion of the inlet flue 3 and both end portions of the inlet flue 3 are less than the average gas flow velocity, and it is considered that the scaling prevention effect is small. When the inclination angle 27 is 5 ° or more, it can be confirmed that the gas flow velocity at the central portion of the inlet flue 3 is equal to or higher than the average gas flow velocity, and an anti-scaling effect can be expected. Therefore, the inclination angle 27 is 5 ° or more. Is desirable.

  However, if the inclination angle 27 is increased, the cross-sectional area decreases, so that the gas pressure loss also increases, and it is necessary to set it in consideration of the power limit of an inlet fan (not shown) disposed in the exhaust gas inlet flue 3.

  The cross-sectional view of the gas inlet flue 3 shown in FIG. 8 is a configuration in which a flat portion having an arbitrary width is provided at the apex 26 portion of the convex inclined surface 25 in this embodiment, and FIG. 9 shows the convex inclined surface. The cross-sectional view of the gas inlet flue 3 of the present Example which provided the flat part of arbitrary width in the both ends of 25 is shown. Moreover, the flat part shown in FIG.8 and FIG.9 may each be provided independently, and may provide both.

DESCRIPTION OF SYMBOLS 1 Flue gas 2 Inclined part 3 Flue gas inlet flue 4 Absorption tower 5 Spray header 6 Branch spray header 7 Spray nozzle 8 Limestone slurry tank 9 Limestone slurry 10 Limestone slurry pump 11 Absorption tower liquid storage part 12 Absorption tower circulation pump 13 Circulation piping 14 Oxidation air blower 15 Absorption tower outlet 20 Step 21 at the time of convex slope installation 21 Flushing device 22 Connection part of inlet flue and absorption tower 23 Flushing device 25 Convex slope surface 26 Convex slope apex 27 Convex slope inclination angle 28 Inlet flue Bottom 29 Inclined surface upstream of inlet flue

Claims (6)

An absorber that absorbs and removes dust, sulfur oxides, and substances caused by components contained in fuel contained in the exhaust gas discharged from the combustion device with an absorbent slurry, and an absorbent slurry that flows down from the absorber. A wet flue gas desulfurization device having an absorption tower composed of a tank part for temporary storage,
A wet flue gas desulfurization apparatus characterized in that an inlet flue for the exhaust gas is provided on a side wall of the absorption tower, and a bottom surface of the inlet flue is formed in a convex shape having inclined surfaces descending from the center toward both sides. .   The wet flue gas desulfurization apparatus according to claim 1, wherein an inclination angle of the inclined surface descending from the center of the bottom surface of the gas inlet flue toward both sides is set to 5 ° or more with respect to a horizontal plane.   A flushing device is provided at the apex portion of the inclined surface formed in a convex shape on the bottom surface of the gas inlet flue and / or the portion connected to the inlet flue side wall at both end portions of the inclined surface formed in a convex shape. The wet flue gas desulfurization apparatus according to claim 1 or 2, characterized in that   The water washing device installed at the apex portion of the inclined surface formed in a convex shape is a cleaning water injection device that injects cleaning water toward both ends of the bottom surface along the inclined surface. 3. The wet flue gas desulfurization apparatus according to 3.   The flushing device installed at the portion connected to the inlet flue side wall at both ends of the inclined surface formed in a convex shape is a flushing water jetting device that jets flushing water from the gas inlet flue side toward the inside of the absorption tower. The wet flue gas desulfurization apparatus according to claim 3, wherein   A plurality of the flushing devices are installed from the upstream to the downstream of the gas inlet flue, and the washing water injection force of each flushing device is configured to sequentially increase from the upstream to the downstream of the gas inlet flue. The wet flue gas desulfurization apparatus according to any one of claims 3 to 5.

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