JP2017205698A - Rectifier and electric dust collector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize speed distribution of a gas on a downstream side of an enlarged duct.SOLUTION: A rectifier 7 is provided on an electric dust collector 1, which comprises a duct collection casing 2 having an inlet part 2D having a rectangular cross-sectional shape which is so formed that a height dimension and a width dimension thereof are different from each other and an enlarged duct 5 which is connected to the inlet part 2D in the dust collection box 2 and which is so formed that a cross section thereof is gradually increased toward the inlet part 2D, and rectifies a flow of a gas passing in the enlarged duct 5. The rectifier 7 has a plate-like member 7A which partitions the interior of the enlarged duct 5 into an upstream side and a downstream side of the gas. In the plate-like member 7A, plural rectangular opening holes 7B, of which a height dimension and a width dimension are different from each other, are formed in parallel in a height direction and a width direction. A direction of extension of a long side of the opening hole 7B is coincident with that of a long side of the inlet part 2D.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rectifier and an electric dust collector to which the rectifier is applied.

  For example, Patent Document 1 discloses a technique in which a perforated plate is provided in an enlarged duct at an inlet portion in an electrostatic precipitator to make the gas velocity distribution downstream of the enlarged duct uniform.

JP 2001-232235 A

  In the conventional electrostatic precipitator as shown in Patent Document 1, the hole shape of the perforated plate is square.

  However, recent electrostatic precipitators are desired to increase the capacity and increase the efficiency of dust collection, and have a cross-sectional shape in which the width dimension is widened due to the restriction of the height dimension. For this reason, there is a problem in that the velocity distribution of the gas downstream of the expansion duct becomes non-uniform due to a difference in spread between the height direction and the width direction in the expansion duct.

  This invention solves the subject mentioned above, and aims at providing the rectifier and electric dust collector which can equalize the velocity distribution of the gas downstream of an expansion duct.

  In order to achieve the above-described object, a rectifier according to an aspect of the present invention includes a dust collection casing having an inlet portion having a rectangular cross-sectional shape having a height dimension and a width dimension that are different from each other. A gas flow that passes through the expansion duct, provided in an electric dust collector that includes an expansion duct that is connected to the inlet portion of the dust casing and has a cross-sectional area that is gradually enlarged toward the inlet portion. A plate-like member that divides the inside of the enlarged duct into an upstream and a downstream of the gas, and the plate-like member has a rectangular shape with different height and width dimensions. A plurality of opening holes are formed in parallel in the height direction and the width direction, and the opening holes have the long sides that coincide with the long sides of the inlet portion.

  According to this rectifying device, the opening hole of the plate-like member is provided with the long side aligned with the long side of the inlet portion so that the rectangular shape of the opening hole of the rectifying device is the inlet portion. Arranged in a rectangular shape. For this reason, the inlet portion has a rectangular cross-sectional shape, and there is a difference in the gas spread between the height direction and the width direction of the enlarged duct. The difference in spread with the direction can be suppressed. As a result, the flow velocity distribution of the gas passing through the expansion duct and reaching the inlet can be made uniform.

  In the rectifier according to one aspect of the present invention, the long side dimension B of the inlet part, the short side dimension H of the inlet part, the long side dimension b of the opening hole, and the short side dimension h of the opening hole are: B / H = (b / h) a is satisfied, and the coefficient a is preferably in the range of 1 ≦ a ≦ 1.8.

  According to this rectifier, B / H and b / h, which are aspect ratios, are approximated, so that the difference in spread between the gas height direction and the width direction can be further suppressed. As a result, the flow velocity distribution of the gas passing through the expansion duct and reaching the inlet can be made more uniform.

  In the rectifier according to one aspect of the present invention, the coefficient a is preferably 1.

  According to this rectifier, since the aspect ratios B / H and b / h are the same, the difference in spread between the height direction and the width direction of the gas can be more significantly suppressed. As a result, the effect of equalizing the flow velocity distribution of the gas passing through the expansion duct and reaching the inlet can be obtained more remarkably.

  The rectifier according to one aspect of the present invention includes another plate-like member that divides the inside of the expansion duct into an upstream and a downstream of the gas, and the other plate-like member has a height of an opening hole. A plurality may be arranged in parallel in the direction and the width direction.

  In this way, even in a rectifying device having a plurality of plate-like members (plate-like members and other plate-like members), rectangles having different height dimensions and width dimensions with respect to at least one plate-like member. If the long opening is provided so as to coincide with the direction in which the long side extends to the long side of the inlet portion, the effect of uniformizing the flow velocity distribution of the gas reaching the inlet portion can be obtained. it can.

  In the rectifier according to one embodiment of the present invention, it is preferable that the plate-like member is disposed on the upstream side of the other plate-like members.

  According to this rectifier, since the plate-like member arranged on the most upstream side passes through the opening hole in a state where the gas flow rate is high in the enlarged duct, the rectifying action is remarkable, and the gas reaching the inlet portion The effect of making the flow velocity distribution uniform can be obtained more remarkably.

  In the rectifier according to one aspect of the present invention, it is preferable that the other plate-like member has a direction in which a long side of the opening hole extends with a long side of the inlet portion.

  Even with this rectifier, it is possible to obtain the effect of uniforming the flow velocity distribution of the gas reaching the inlet.

  In the rectifier according to one aspect of the present invention, the other plate-like member has a shape in which the height dimension and the width dimension of the opening hole are closer to each other plate-like member closer to the downstream side. Is preferred.

  According to this rectifier, since the plate-like member arranged on the most upstream side passes through the opening hole in a state where the gas flow rate is high in the enlarged duct, the rectifying action is remarkable, and the gas reaching the inlet portion The effect of making the flow velocity distribution uniform can be obtained more remarkably. And in the other plate-like members on the downstream side, the height dimension and the width dimension of the opening hole are approximated so as to approach a square shape as it is closer to the downstream side, so that it is arranged on the most upstream side. The gas flow can be rectified so as to maintain the rectification effect in the plate-like member.

  In order to achieve the above object, an electrostatic precipitator according to an aspect of the present invention includes a dust collecting casing having an inlet portion having a rectangular cross-sectional shape formed such that a height dimension and a width dimension are different from each other, A dust collecting portion disposed in the dust collecting casing, an enlarged duct connected to the inlet portion in the dust collecting casing and having a cross-sectional area gradually enlarged toward the inlet portion, and the inside of the enlarged duct Any one of the rectifiers described above for adjusting the flow of the gas passing therethrough.

  According to this electric dust collector, the flow velocity distribution of the gas reaching the inlet portion of the dust collecting casing is made uniform by the rectifier, so that the gas flow velocity distribution in the dust collecting casing is made uniform, and in the dust collecting portion. High dust collection efficiency can be maintained.

  According to the present invention, the gas velocity distribution downstream of the enlarged duct can be made uniform.

FIG. 1 is a longitudinal sectional view of an electrostatic precipitator according to an embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG. 3 is a cross-sectional view taken along the line BB in FIG. FIG. 4 is a partially enlarged front view of the rectifier according to the embodiment of the present invention. FIG. 5 is a partially enlarged side view of the rectifier according to the embodiment of the present invention. FIG. 6 is a schematic configuration diagram of another example of the rectifier according to the embodiment of the present invention.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a longitudinal sectional view of an electric dust collector according to the present embodiment. 2 is a cross-sectional view taken along line AA in FIG. 3 is a cross-sectional view taken along the line BB in FIG. FIG. 4 is a partially enlarged front view of the rectifier according to the present embodiment. FIG. 5 is a partially enlarged side view of the rectifier according to the present embodiment.

  The electric dust collector 1 of this embodiment collects particulates, such as dust in the gas G discharged | emitted in various plants, such as a coal-fired power plant and a heavy oil thermal power plant, for example, The duct 10 through which the gas G flows is collected. Is provided. As shown in FIGS. 1 to 3, the electric dust collector 1 includes a dust collection casing 2, a dust collection unit 3, a hopper 4, an expansion duct 5, a reduction duct 6, and a rectifier 7. I have.

  The dust-collecting casing 2 includes a rectangular upper wall 2A arranged horizontally as a ceiling, a rectangular lower wall 2B arranged horizontally as a bottom, and two directions between the upper wall 2A and the lower wall 2B. Each side wall 2 </ b> C that is erected is configured to form a substantially rectangular cylindrical body as a whole. The dust-collecting casing 2 is configured such that both sides facing each other in the lateral (horizontal) direction are open, and one is an inlet portion 2D and the other is an outlet portion 2E. In the dust collecting casing 2, the gas G flows in a predetermined direction so that the gas G flowing into the inside from one inlet 2 </ b> D flows out from the other outlet 2 </ b> E as indicated by an arrow. The direction in which this gas G flows is defined as the flow direction. In the dust collecting casing 2, the vertical direction in which the side wall 2C is erected is the height direction, and the horizontal direction perpendicular to the gas G flow direction and the vertical direction is the width direction.

  The dust collecting casing 2 has an inlet portion 2D and an outlet portion 2E formed in a rectangular cross-sectional shape, and has a long side extending along the width direction and a short side extending along the height direction. It is arranged to extend.

  The dust collection unit 3 is disposed inside the dust collection casing 2. The dust collecting unit 3 has a dust collecting plate 3A formed in a plate shape so as to extend along the height direction and the flow direction, and a plurality of the dust collecting plates 3A are arranged in parallel in the width direction. Each dust collecting plate 3A collects the fine particles by charging and attracting the fine particles in the gas G by corona discharge generated by applying a voltage between the discharge portions 3B arranged on the side of the dust collecting plate 3A. The fine particles collected on the dust collecting plate 3A are periodically peeled by a peeling mechanism (not shown) in order to prevent the dust collecting performance from being lowered. The dust collection unit 3 is provided in a plurality of stages (two stages in the present embodiment) in the flow direction within the dust collection casing 2.

  The hopper 4 is for storing fine particles that are peeled off from the dust collecting unit 3. For this reason, the hopper 4 forms a space S recessed downward from the lower wall 2 </ b> B of the lower part of the dust collection casing 2 below the dust collection unit 3. The hopper 4 is provided to be inclined so that the inner wall surface 4A surrounding the space S gradually narrows toward the bottom 4B in order to collect and store the fine particles. For this reason, the fine particles falling on the hopper 4 are collected toward the bottom 4B along the inclination of the inner wall surface 4A. Although not clearly shown in the drawing, the hopper 4 is provided so that the narrowed bottom 4B is opened, and is configured to discharge the stored fine particles. As described above, since the hopper 4 is provided with a plurality of stages of the dust collecting sections 3, the hopper 4 is also provided with a plurality of stages (two stages in the present embodiment) in the flow direction like the dust collecting section 3.

  The expansion duct 5 connects the upstream portion of the duct 10 in the flow direction and the inlet portion 2D of the dust collecting casing 2. Here, the duct 10 is a passage through which the gas G flows, and it is necessary to relatively increase the flow rate of the gas G so that fine particles do not accumulate on the inner wall (for example, 10 m / s or more). In order to collect fine particles efficiently, it is necessary to reduce the flow rate of the gas G (for example, about 1 m / s). For this reason, the duct 10 is a relatively small-diameter passage, and the dust collecting casing 2 is formed as a cylindrical body having a larger diameter than the duct 10 with a large opening at the entrance 2D. Further, the duct 10 has a rectangular cross section formed by an upper wall 10A, a lower wall 10B, and both side walls 10C.

  The enlarged duct 5 is formed such that the cross-sectional area sequentially increases from the small diameter duct 10 to the large diameter inlet portion 2D. Specifically, the enlarged duct 5 is an upper wall that connects the upper wall 10A of the duct 10 and the upper wall 2A of the dust collecting casing 2 in a state where the center of the duct 10 and the center of the inlet portion 2D are aligned in the flow direction. 5A, a lower wall 5B connecting the lower wall 10B of the duct 10 and the lower wall 2B of the dust collecting casing 2, and both side walls 5C connecting the both side walls 10C of the duct 10 and the both side walls 2C of the dust collecting casing 2 ,have. The enlarged duct 5 is formed such that the upper wall 5A, the lower wall 5B, and the both side walls 5C extend obliquely from the duct 10 to the inlet portion 2D and away from the center. The cross-sectional areas in the width direction and the width direction are formed to be sequentially enlarged. Therefore, the expansion duct 5 is sent from the duct 10 to the inlet 2D into the dust collecting casing 2 while decreasing the flow rate of the gas G in the duct 10 by sequentially increasing the cross-sectional area.

  The reduction duct 6 connects the outlet portion 2E of the dust collecting casing 2 and the downstream portion of the duct 10 in the flow direction. In the dust collecting casing 2, the outlet portion 2 </ b> E has the same diameter as that of the inlet portion 2 </ b> D and is larger than the diameter of the duct 10. Therefore, the reduced duct 6 is formed by reducing the cross-sectional area sequentially from the large diameter outlet portion 2E to the small diameter duct 10. Specifically, the reduced duct 6 is an upper wall that connects the upper wall 2A of the dust collecting casing 2 and the upper wall 10A of the duct 10 with the center of the outlet 2E and the center of the duct 10 aligned in the flow direction. 6A, a lower wall 6B connecting the lower wall 2B of the dust collecting casing 2 and the lower wall 10B of the duct 10, and both side walls 6C connecting the both side walls 2C of the dust collecting casing 2 and the both side walls 10C of the duct 10 ,have. The reduced duct 6 is formed so that the upper wall 6A, the lower wall 6B, and both side walls 6C are narrowed obliquely so as to be away from the center from the outlet 2E to the duct 10, so that the reduced duct 6 reaches the duct 10 from the outlet 2E. The cross-sectional areas in the width direction and the width direction are sequentially reduced. Therefore, the reduced duct 6 reaches the duct 10 from the outlet portion 2E, and the cross-sectional area is sequentially reduced, thereby increasing the flow velocity (for example, about 1 m / s) of the gas G in the dust collecting casing 2 (for example, 10 m / s or more). ) And sent to the duct 10.

  The rectifying device 7 is provided in the enlarged duct 5 to adjust the flow of the gas G passing through the enlarged duct 5. The rectifier 7 has a plate-like member 7A. The plate-like member 7 </ b> A is a plate body that is arranged so as to extend in the width direction and the height direction in the enlarged duct 5 and divides the enlarged duct 5 in the flow direction. The plate-like member 7A is provided with an opening hole 7B penetrating in the flow direction. The opening hole 7B has a side extending in the height direction and a side extending in the width direction, is formed in a rectangular shape, and a plurality of the opening holes 7B are juxtaposed in the height direction and the width direction. Each opening hole 7B has the same shape and the same size.

  As shown in FIG. 4, each opening hole 7 </ b> B of the rectifying device 7 is formed in a rectangular shape, the long side extends along the width direction, and the short side extends along the height direction. It is arranged to extend. Further, as described above, the inlet portion 2D to which the expansion duct 5 provided with the rectifying device 7 is connected is formed in a rectangular cross-sectional shape, and the long side is arranged extending in the width direction. The short side extends along the height direction. That is, the opening hole 7B is provided such that the long side coincides with the extending direction of the long side of the inlet portion 2D and the short side thereof coincides with the extending direction of the short side of the inlet portion 2D.

  In the rectifying device 7 configured in this way, the opening hole 7B of the plate-like member 7A is provided with the long side aligned with the long side of the inlet portion 2D. The rectangular shape of the hole 7B is arranged according to the rectangular shape of the inlet portion 2D. Conventionally, the inlet portion 2D has a rectangular cross-sectional shape, and the difference in the spread of the gas G between the height direction and the width direction of the expansion duct 5 causes, for example, a uniform flow velocity distribution in the height direction. If there is a tendency, the center in the width direction has a higher flow velocity than both sides. It becomes uniform. In this respect, in the rectifying device 7 of the present embodiment, the difference in spread between the height direction and the width direction of the gas G can be suppressed by the shape and arrangement of the opening hole 7B described above. As a result, as indicated by broken lines in FIGS. 1 and 2, the flow velocity distribution in the height direction and the width direction of the gas G passing through the expansion duct 5 and reaching the inlet 2D can be made uniform.

  In addition, the inner diameter of the duct 10 and the inner diameter of the inlet portion 2D may be similar in cross-sectional area, but may not be similar. If it is not similar, the flow velocity distribution of the gas G from the duct 10 through the enlarged duct 5 to the inlet 2D becomes non-uniform, but even in such a case, According to the rectifier 7, the flow velocity distribution of the gas G reaching the inlet 2D can be made uniform.

  Moreover, in the rectifier 7 of this embodiment, as shown in FIGS. 3 and 4, the long side dimension B of the inlet portion 2D, the short side dimension H of the inlet portion 2D, the long side dimension b of the opening hole 7B, and the opening It is preferable that the short side dimension h of the hole 7B satisfies the relationship of B / H = (b / h) a, and the coefficient a is in the range of 1 ≦ a ≦ 1.8.

  According to this rectifier 7, B / H and b / h, which are aspect ratios, are approximated, so that the difference in spread between the height direction and the width direction of the gas G can be further suppressed. As a result, the flow velocity distribution of the gas G passing through the enlarged duct 5 and reaching the inlet 2D can be made more uniform.

  In particular, in the rectifier 7 of this embodiment, it is more preferable that the coefficient a is 1 and B / H = b / h.

  According to this rectifier 7, since the B / H and b / h, which are aspect ratios, are the same, the difference in spread between the height direction and the width direction of the gas G can be more significantly suppressed. As a result, the effect of equalizing the flow velocity distribution of the gas G passing through the expansion duct 5 and reaching the inlet 2D can be obtained more significantly.

  By the way, as shown in FIGS. 4 and 5, the rectifying device 7 of the present embodiment includes a plate-like member 7 </ b> A and an opening hole 7 </ b> B formed by stacking strip-like plate materials 7 a and 7 b in a lattice shape. 4 and 5, the plate material 7 a is arranged extending in the width direction, and the plate material 7 b is arranged extending in the height direction. Further, as shown in FIG. 5, the plate member 7b in the height direction is arranged on the upstream side of the gas G in the flow direction, and the plate material 7a in the width direction is arranged on the downstream side of the gas G in the flow direction. Thus, the opening hole 7B can be easily formed by stacking the strip-shaped plate materials 7a and 7b in a lattice shape.

  FIG. 6 is a schematic configuration diagram of another example of the rectifier according to the present embodiment.

  The rectifier 7 shown in FIG. 6 is provided so that a plurality of plate-like members 7A divide the inside of the enlarged duct 5 into a plurality of upstream and downstream sides of the gas G. FIG. 6 shows a form in which three plate-like members 7A are arranged along the flow direction of the gas G. Each plate-like member 7A is provided with an opening 7B penetrating in the flow direction. The opening hole 7B has a side extending in the height direction and a side extending in the width direction, is formed in a rectangular shape, and a plurality of the opening holes 7B are juxtaposed in the height direction and the width direction. Each opening hole 7B in one plate-like member 7A has the same shape and the same size.

  Thus, in the rectifying device 7 configured as described above, in the plate-like member 7A arranged on the most upstream side, the opening hole 7B is formed in a rectangular shape having a height dimension and a width dimension different from each other, and its long side is It is preferable that the long side of the inner diameter of the inlet portion 2D matches the extending direction, and the short side is provided so as to match the extended direction of the short side of the inner diameter of the inlet portion 2D.

  In the other plate-like member 7A on the downstream side, it is preferable that the opening hole 7B is formed so that the height dimension and the width dimension approximate to a square shape as it is closer to the downstream side.

  As described above, in the rectifying device 7 configured as described above, the plate-like member 7A arranged on the most upstream side passes through the opening hole 7B in a state where the flow rate of the gas G is high in the expansion duct 5, and thus the rectifying action is remarkable. Thus, the effect of making the flow velocity distribution of the gas G reaching the inlet 2D uniform can be obtained more remarkably. And in the other plate-like member 7A on the downstream side, the height dimension and the width dimension of the opening hole 7B are approximated so as to be closer to the downstream side and closer to the square shape, so that it is arranged on the most upstream side. The flow of the gas G can be rectified so as to maintain the rectification effect in the plate member 7A.

  Further, the opening hole 7B in the plate-like member 7A arranged on the most upstream side also satisfies the relationship of B / H = (b / h) a as described above, and the coefficient a is 1 ≦ a ≦ 1. Is preferably in the range of .8, and more preferably, the coefficient a is 1 and B / H = b / h.

  In the rectifying device 7 shown in FIG. 6, the opening hole 7B of at least one of the plurality of plate-like members 7A has the above-described configuration of the opening hole 7B in the plate-like member 7A arranged on the most upstream side. In the plate-like member 7A, the effect of uniformizing the flow velocity distribution of the gas G reaching the inlet portion 2D can be obtained even if it is all square.

  Further, in the rectifier 7 shown in FIG. 6, the opening hole 7B of the plate member 7A on the most upstream side has the above-described configuration of the opening hole 7B in the plate member 7A arranged on the most upstream side. In the plate-like member 7A, the flow of the gas G can be rectified so as to maintain the rectification effect in the plate-like member 7A arranged on the most upstream side even if it is all square.

  Further, in the rectifying device 7 shown in FIG. 6, the opening holes 7B of all the plate-like members 7A are configured as the opening holes 7B in the plate-like member 7A arranged on the most upstream side as described above, and reach the inlet portion 2D. An effect of making the flow velocity distribution of the gas G uniform can be obtained.

  In the above-described embodiment, according to the electrostatic precipitator 1 including any one of the rectifiers 7, the flow velocity distribution of the gas G reaching the inlet 2 </ b> D of the dust collector casing 2 is made uniform by the rectifier 7. Therefore, the flow velocity distribution of the gas G in the dust collection casing 2 is made uniform, and high dust collection efficiency can be maintained in the dust collection section 3.

DESCRIPTION OF SYMBOLS 1 Electric dust collector 2 Dust-collecting casing 2D Inlet part 3 Dust-collecting part 5 Expansion duct 7 Rectifier 7A Plate-like member 7B Opening hole a Coefficient B Inlet part long side dimension H Inlet part short side dimension b Opening hole length Side dimension h Short side dimension of opening hole G Gas

Claims (8)

A dust collecting casing having an inlet portion having a rectangular cross-sectional shape formed with a height dimension and a width dimension different from each other, and a cross-sectional area gradually connecting toward the inlet portion connected to the inlet portion in the dust collecting casing A rectifier that is provided in an electric dust collector equipped with an enlarged duct formed by enlarging, and regulates the flow of gas passing through the enlarged duct,
A plate-like member that divides the inside of the expansion duct into upstream and downstream of the gas;
In the plate-like member, a plurality of rectangular opening holes having different height dimensions and width dimensions are formed in parallel in the height direction and the width direction,
The opening hole is a rectifier in which the long side coincides with the direction in which the long side extends to the long side of the inlet portion.   The long side dimension B of the inlet part, the short side dimension H of the inlet part, the long side dimension b of the opening hole, and the short side dimension h of the opening hole are B / H = (b / h) a And the coefficient a is in the range of 1 ≦ a ≦ 1.8.   The rectifier according to claim 2, wherein the coefficient a is 1. Other plate-like members that divide the inside of the expansion duct into upstream and downstream of the gas,
The rectifier according to any one of claims 1 to 3, wherein the other plate-like member has a plurality of opening holes arranged in parallel in a height direction and a width direction.   The rectifier according to claim 4, wherein the plate-like member is disposed on the upstream side of the other plate-like member.   The rectifier according to claim 5, wherein the other plate-like member has a direction in which a long side of the opening hole extends with a long side of the inlet portion.   The rectifier according to claim 5, wherein the other plate-like member has a shape in which the height dimension and the width dimension of the opening hole are closer to each other plate-like member closer to the downstream side. A dust-collecting casing having an inlet portion having a rectangular cross-sectional shape formed with a height dimension and a width dimension different from each other;
A dust collecting part disposed in the dust collecting casing;
An enlarged duct that is connected to the inlet portion in the dust-collecting casing and has a cross-sectional area gradually enlarged toward the inlet portion,
The rectifier according to any one of claims 1 to 7, which regulates the flow of gas passing through the expansion duct;
An electric dust collector.

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