WO2019142573A1 - Electrostatic precipitator - Google Patents

Electrostatic precipitator Download PDF

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Publication number
WO2019142573A1
WO2019142573A1 PCT/JP2018/046415 JP2018046415W WO2019142573A1 WO 2019142573 A1 WO2019142573 A1 WO 2019142573A1 JP 2018046415 W JP2018046415 W JP 2018046415W WO 2019142573 A1 WO2019142573 A1 WO 2019142573A1
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Prior art keywords
dust collection
dust
electrode
pipe
flat plate
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PCT/JP2018/046415
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French (fr)
Japanese (ja)
Inventor
一隆 富松
加藤　雅也
上田　泰稔
Original Assignee
三菱日立パワーシステムズ環境ソリューション株式会社
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Publication of WO2019142573A1 publication Critical patent/WO2019142573A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34—Constructional details or accessories or operation thereof
    • B03C3/40—Electrode constructions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34—Constructional details or accessories or operation thereof
    • B03C3/40—Electrode constructions
    • B03C3/45—Collecting-electrodes
    • B03C3/47—Collecting-electrodes flat, e.g. plates, discs, gratings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34—Constructional details or accessories or operation thereof
    • B03C3/40—Electrode constructions
    • B03C3/45—Collecting-electrodes
    • B03C3/49—Collecting-electrodes tubular

Definitions

  • the present invention relates to an electrostatic precipitator.
  • a high DC voltage is applied between the dust collection electrode and the discharge electrode to perform stable corona discharge on the discharge electrode, thereby charging dust in the gas flow.
  • charged dust is collected at the dust collection electrode by the action of the Coulomb force acting on the dust under an electric field between the discharge electrode and the dust collection electrode.
  • the electrostatic precipitator of patent documents 1 and 2 is provided with a plurality of penetration holes for letting dust pass, and is provided with a dust collection pole which had a closed space for collecting dust inside.
  • trapped dust is less likely to be scattered again by confining the dust in the closed space via the through holes.
  • the electrostatic precipitator of Patent Document 3 includes a dust collection electrode including an earth electrode having an aperture ratio of 65% to 85%, and a dust collection filter layer for collecting gas.
  • a dust collection electrode including an earth electrode having an aperture ratio of 65% to 85%
  • a dust collection filter layer for collecting gas.
  • Patent No. 5761461 gazette Patent No. 5705461 gazette Patent No. 4823691
  • the dust collection efficiency ⁇ in the electrostatic precipitator can be calculated by the well-known German equation (equation (1)) below.
  • w a dust collection index (moving speed of particulate matter)
  • f a dust collection area per unit gas amount.
  • ⁇ 1-exp (-w ⁇ f) (1)
  • the moving speed w of the dust is determined to be determined by the relationship between the Coulomb force and the viscous drag of the gas.
  • dust is said to move from the discharge electrode in the electric field, and the ion wind is not directly considered in the influence on performance.
  • the dust concentration which is the premise of its performance design, has the precondition that it is always uniform in the dust collection space between the discharge electrode and the dust collection electrode, and the ion wind causes gas turbulence, It is considered as one of the factors that make the dust concentration uniform.
  • the ion wind generates negative ions by corona discharge at the discharge electrode when a negative voltage is applied between the electrodes, and as a result, it is generated by positive ions in the case of a positive voltage.
  • a negative voltage is described in order to consider the industrial electrostatic precipitator as a base, but the same is true even if it is positive.
  • the ion wind generated by the discharge electrode flows across the gas flow toward the dust collection electrode.
  • the ion wind that has reached the collecting electrode is reversed at the collecting electrode to change the flow direction. This causes a helical turbulence between the electrodes.
  • the flow from the discharge electrode to the dust collection electrode has an effect of carrying dust to the vicinity of the dust collection electrode.
  • the dust carried to the vicinity of the dust collection electrode is finally collected by the Coulomb force.
  • the rewinding of the ion wind reversed by the dust collection electrode moves dust in a direction away from the dust collection electrode that is the collecting body, and thus has an effect of inhibiting the dust collection.
  • dust contained in the gas has a predetermined particle size distribution
  • relatively small particle size dust is largely affected by the unwinding of the ion wind as described above, and the collection efficiency does not increase. There is a fear.
  • Patent Document 3 describes an electrostatic precipitator in consideration of the effect of ion wind.
  • the structure is such that the ion wind is sent to the filter layer behind the dust collection electrode having the opening, and the structure is complicated in order to collect dust in a region not affected by the main gas. In some cases, it was difficult to separate and collect dust attached to the filter layer in the dry state.
  • This indication is made in view of such a situation, and it aims at providing an electric dust collector which can raise dust collection efficiency also to dust which has particle size distribution.
  • An electrostatic precipitator is disposed in parallel to a first dust collection electrode which is provided along a gas flow direction and has no opening, and the first dust collection electrode.
  • a first dust collection unit having a first discharge electrode, a second dust collection electrode disposed on the downstream side of the gas flow direction of the first dust collection unit, and an opening, and the second dust collection electrode
  • a second dust collection unit having a second discharge electrode arranged in parallel to each other.
  • the first dust collection unit By arranging the first dust collection unit having a plate-shaped first dust collection electrode without an opening on the upstream side of the gas flow, dust having a relatively large particle size among dust contained in the gas can be obtained. Collect. In addition, since the first dust collection electrode has no opening, the dust collection area can be increased and a large amount of dust can be collected as compared with the case where the opening is not provided.
  • the 2nd dust collection part which has the 2nd dust collection pole which has an opening in the downstream of the gas flow direction of the 1st dust collection part was arranged.
  • the first dust collection unit suitable for collecting relatively large dust among the dust having particle size distribution and the second dust collection unit suitable for collecting relatively small dust By combining them, even dust having a predetermined particle size distribution can be effectively collected.
  • the second dust collection electrode include columnar bodies such as cylinders arranged at predetermined intervals, flat plates or folded plates having a plurality of openings, and metal mesh.
  • the aperture ratio of the second dust collection electrode is 10% or more and 70% or less.
  • the second dust collection electrode is a plurality of columnar bodies disposed at predetermined intervals in the gas flow direction, and a cross section of the columnar bodies
  • the equivalent diameter of is 30 mm or more and 80 mm or less.
  • the equivalent diameter of the cross section of the cast body was 30 mm or more.
  • the equivalent diameter of the cross section of the columnar body was 80 mm or less.
  • equivalent diameter is meant a circular diameter equivalent to the cross section of a given shape.
  • the cross-section is circular, this corresponds to its diameter.
  • the pipe-shaped member made into circular cross section for example is mentioned.
  • the cross-sectional shape in addition to the circular shape, an oval, an oval, a polygon or the like is used.
  • not only hollow but also solid may be used as a dust collection electrode.
  • a second dust collection part having a first dust collection part having a plate-like first dust collection electrode not having an opening, and a second dust collection electrode provided on the downstream side of the first dust collection part and having an opening
  • the dust collection efficiency can be enhanced also for dust having a particle size distribution by combining the
  • the electrostatic precipitator 1 is used, for example, in a thermal power plant using coal as a fuel, and recovers dust (particulate matter) in combustion exhaust gas led from a boiler.
  • FIG. 1 shows a longitudinal sectional view of the electrostatic precipitator according to the present embodiment as viewed from above.
  • the gas flow G is a horizontal flow, and flows from the left side to the right side of the drawing.
  • the electrostatic precipitator 1 includes, in the casing 2, a flat plate dust collection part (first dust collection part) A, an upstream pipe dust collection part (second dust collection part) B, and a gas flow G along the downstream side. And a side pipe dust collection unit (second dust collection unit) C.
  • the casing 2 includes a gas inlet 2a, a main body 2b, and a gas outlet 2c.
  • the gas flowing in from the gas inlet 2a is guided to the main body 2b and collected by the dust collecting units A, B, and C, and then discharged from the gas outlet 2c to the outside.
  • the flat plate collecting portion A includes a plurality of flat plate collecting electrodes 4A provided so as to extend in the gas flow G direction, and a discharge electrode 5A provided so as to be separated in parallel with the flat plate collecting electrodes 4A. Have.
  • the flat plate collecting electrode 4A and the discharge electrode 5A are separated from each other and electrically insulated.
  • the discharge electrode 5A is also insulated from the casing 2.
  • the flat plate collecting electrode 4A is grounded, and a power supply 6A having a negative polarity is connected to the discharge electrode 5A.
  • Each flat plate collecting electrode 4A is a metal flat plate having no opening.
  • the discharge electrode 5A has a mounting base 7A and a plurality of corona discharge parts 8A.
  • the mounting base 7A is a rod-like or plate-like member made of a conductive material.
  • the mounting base 7A is disposed parallel to the facing flat plate collecting electrode 4A.
  • the corona discharge portion 8A generates a corona discharge by applying a voltage to the discharge electrode 5A.
  • the corona discharge portion 8A is a protrusion fixed to the mounting base 7A so as to protrude toward the flat plate collecting electrode 4A facing the corona discharge portion 8A.
  • a plurality of corona discharge portions 8A are disposed in the direction orthogonal to the paper surface, that is, in the height direction.
  • the upstream-side pipe dust collection unit B includes a pipe dust collection electrode 4B and a discharge electrode 5B fixed to the mounting base 7B.
  • the pipe dust collection electrode 4B is a discrete dust collection electrode in which a plurality of pipe members 4Ba are arranged in the flow direction of the gas flow G with a predetermined interval. Therefore, the pipe dust collection electrode 4B is provided to have an opening.
  • Each pipe member 4Ba is made of rigid metal.
  • Each pipe member 4Ba is arranged in the vertical direction (vertical direction in the drawing) so that the axis is orthogonal to the gas flow G.
  • the pipe members 4Ba arranged in the gas flow G direction are fixed to each other using a common frame.
  • the discharge electrode 5B has a configuration similar to that of the discharge electrode 5A of the flat plate dust collection part A, and has a plurality of corona discharge parts 8B. Each corona discharge portion 8B is disposed in the center of the adjacent pipe member 4Ba in the gas flow G direction.
  • the pipe collecting electrode 4B and the discharging electrode 5B are separated from each other and electrically insulated.
  • the discharge electrode 5B is also insulated from the casing 2.
  • the pipe dust collecting electrode 4B is grounded, and a power supply 6B having a negative polarity is connected to the discharge electrode 5B.
  • the power supply 6B can set a voltage different from that of the power supply 6A of the flat plate dust collection part A.
  • the downstream side pipe dust collection unit C includes a pipe dust collection electrode 4C and a discharge electrode 5C fixed to the mounting base 7C.
  • the pipe dust collection electrode 4C has the same configuration as the pipe dust collection electrode 4B of the upstream side pipe dust collection unit B.
  • the discharge electrode 5 ⁇ / b> C has a configuration similar to that of the discharge electrode 5 ⁇ / b> B of the upstream-side pipe dust collection unit B.
  • the distance between the pipe members 4Ca and the distance between the corona discharge parts 8C may be different from the distance between the pipe members 4Ba of the upstream side pipe dust collection part B and the corona discharge parts 8B.
  • a voltage different from the power supply 6A of the flat plate dust collection part A and the power supply 6B of the upstream side pipe dust collection part B can be set as the power supply 6C.
  • FIG. 2 shows the positional relationship between the pipe members 4Ba and 4Ca of the pipe dust collection electrodes 4B and 4C of the upstream side pipe dust collection part B and the downstream side pipe dust collection part C and the corona discharge parts 8B and 8C.
  • the center-to-center pitch Pc of the pipe members 4Ba and 4Ca and the center-to-center pitch Pd of the corona discharge portions 8B and 8C are equal to each other.
  • corona discharge parts 8B and 8C so as to be opposed between the adjacent pipe members 4Ba and 4Ca.
  • the corona discharge portion 8B of the cross section of the pipe members 4Ba, 4Ca, in which the electric lines of force are equally distributed to the pipe members 4Ba, 4Ca , 8C can reach the electric force line to the depth side.
  • the symbol D shown in FIG. 2 is the distance in the orthogonal direction (vertical direction in the figure) between the pipe members 4Ba and 4Ca and the corona discharge parts 8B and 8C, and is, for example, 125 mm to 250 mm.
  • d is the equivalent diameter of the pipe members 4Ba and 4Ca.
  • equivalent diameter is meant the diameter of a circle (having the same area) equivalent to the cross section of a given shape. Therefore, when the cross section of pipe member 4Ba, 4Ca is circular like this embodiment, it corresponds to the diameter.
  • the aperture ratio ⁇ is set to 10% or more and 70% or less. The ground will be described later with reference to FIG.
  • the equivalent diameter d of the pipe members 4Ba and 4Ca is 30 mm or more and 80 mm or less.
  • the reason why the equivalent diameter d of the cross section of the pipe dust collecting electrode 4B, 4C is 30 mm or more is as follows.
  • the equivalent diameter d is reduced, the concentration of the electric field is increased and the dust collection property is enhanced.
  • the equivalent diameter d becomes too small, as shown in FIG. 4, the peak value of the electric field strength becomes large and the spark electric field strength if the current density (for example, 0.3 mA / m 2 ) necessary for dust collection is maintained. Spark discharge occurs over 10kV / cm of Therefore, the lower limit of the equivalent diameter d is 30 mm.
  • the reason for setting the equivalent diameter d of the cross sections of the pipe members 4Ba and 4Ca to 80 mm or less is as follows. If the equivalent diameter d is too large, the increase of the electric field intensity in the vicinity of the pipe members 4Ba and 4Ca (to be described later with reference to FIG. 6) is almost eliminated, and the average electric field intensity of the flat plate collecting electrode 4A without holes (2 kV It becomes about / cm). In addition, if the equivalent diameter d is large, the gas flow is affected and a vortex is generated. Therefore, the upper limit of the equivalent diameter d is 80 mm. For example, the average electric field strength when the equivalent diameter d is 30 mm calculated under the same conditions as described above is 5.7 kV / cm.
  • the vertical axis in FIG. 5 is the average electric field strength, which is the electric field strength averaged over the surface area of the pipe dust collecting electrodes 4B and 4C. This average electric field strength is different from the peak electric field strength on the vertical axis of FIG.
  • the peak electric field strength is the electric field strength at the position of the highest electric field strength among the surfaces of the pipe dust collecting electrodes 4B and 4C.
  • the horizontal axis indicates the position, and it is assumed that the corona discharge parts 8B and 8C are located at the position corresponding to the y axis.
  • the vertical axis is the electric field strength. The electric field strength is highest at the positions of the corona discharge parts 8B and 8C, and after increasing the local value between the pipe members 4Ba and 4Ca, increases while going to the pipe members 4Ba and 4Ca again.
  • a region Z2 closer to the corona discharge portions 8B and 8C than the region Z1 is a dominant region of the ion wind.
  • the dust P in the gas is led to the pipe members 4Ba and 4Ca mainly along with the ion wind.
  • FIG. 7 shows the electric field strength in the case of using the flat plate collecting electrode 4A without the holes (openings).
  • the absolute value of the electric field intensity in the vicinity of the flat plate dust collection electrode 4A is smaller than that of the pipe members 4Ba and 4Ca shown in FIG. Therefore, it is understood that the dust collection performance is inferior to the pipe dust collection electrodes 4B and 4C.
  • the flat dust collection electrode 4A sufficient collection performance is exhibited with respect to relatively large dust less affected by the ion wind.
  • FIG. 8 shows the dust collection area ratio to the opening ratio ⁇ .
  • the dust collection area ratio is the dust collection area when exhibiting the same dust collection performance when the dust collection performance at an aperture ratio of 0% (in the case of no gap) is 1 as in the flat plate dust collection electrode 4A. It is shown. Therefore, the smaller the dust collection area ratio, the higher the collection efficiency.
  • the aperture ratio ⁇ is preferably 10% to 70% (application range).
  • the electrostatic precipitator 1 is provided with a striking device for peeling off the particulate matter adhering to the dust collection electrodes 4A, 4B, 4C.
  • the beating apparatus has a hammer, and the hammer strikes on the dust collection electrodes 4A, 4B, 4C to separate and remove dust attached to the surface by vibration. Note that the method of removing dust from the dust collection electrodes 4A, 4B, 4C is not limited to beating using a beating apparatus.
  • dust is removed from the dust collection electrodes 4A, 4B, 4C by a method of blowing a gas to dust collected on the collection electrodes 4A, 4B, 4C, or a method of irradiating sound waves using a sonic horn You may
  • the particulate matter may be removed from the dust collection electrodes 4A, 4B, 4C by cleaning with a cleaning liquid performed by a wet type electrostatic precipitator.
  • the operation of the electrostatic precipitator 1 of the present embodiment will be described.
  • the electrostatic precipitator 1 by applying a voltage to the discharge electrodes 5A, 5B, 5C, corona discharge occurs at the tip of the corona discharge parts 8A, 8B, 8C.
  • the dust contained in the gas stream G is charged by corona discharge.
  • the charged dust moves to the vicinity of the collecting electrode by the ion wind flowing toward the collecting electrode, and is then attracted and collected near the flat collecting electrode 4A by the Coulomb force .
  • dusts having a particle size distribution dusts having relatively large particle sizes are preferentially collected. This is because dust with a larger particle size has a larger surface area and larger air resistance in proportion to the particle size than dust with a smaller particle size, while the amount of charge increases in proportion to the square of the particle size, resulting in coulombs This is because the movement speed increases as the effect of force increases. Since dust with a large particle size is not easily affected by the ion wind, there is little influence by the unwinding of the ion wind even at a dust collection electrode without an opening.
  • FIG. 9 shows the dust collection efficiency (EP efficiency) by the electrostatic precipitator 1.
  • the horizontal axis indicates the position in the gas flow G direction. Therefore, the flat plate dust collection part A is positioned upstream, and the pipe dust collection parts B and C are positioned downstream thereof.
  • the EP efficiency of the flat-plate dust collection part A shows a good collection efficiency because it collects a large amount of relatively large dust on the upstream side of the gas flow G, but as the downstream side of the gas flow G is relatively small dust
  • the collection efficiency becomes relatively flat because the The EP efficiency of the pipe dust collecting parts B and C is not as good as that of the flat sheet dust collecting part A because a relatively large amount of dust is present on the upstream side.
  • the following effects are achieved.
  • the flat plate dust collection part A having the flat plate dust collection electrode 4A in the form of a plate having no opening on the upstream side of the gas flow G, relatively large dust contained in the gas is collected Do. Further, since the flat plate dust collection electrode 4A does not have an opening, the dust collection area becomes large and a large amount of dust can be collected.
  • pipe dust collection parts B and C having pipe collection electrodes 4B and 4C having openings are disposed.
  • the ion wind By passing a part of the ion wind generated between the discharge electrodes 5B and 5C through the openings of the pipe dust collection electrodes 4B and 4C, the ion wind is inverted and separated at the pipe dust collection electrodes 4B and 4C. Suppress the flow (rewind). Thereby, even relatively small dust can be guided to the vicinity of the pipe dust collection electrodes 4B and 4C by the ion wind, and can be collected by the Coulomb force in the vicinity of the pipe dust collection electrodes 4B and 4C. Therefore, relatively small dust which could not be collected by the flat plate dust collection part A can be collected by the pipe dust collection parts B and C on the downstream side.
  • the flat plate dust collection part A suitable for collecting relatively large dust among the dust having particle size distribution and the pipe dust collection parts B and C suitable for collecting relatively small dust By combining these, even dust having a predetermined particle size distribution can be effectively collected.
  • the opening ratio ⁇ of the pipe dust collection electrodes 4B and 4C is set to 10% or more and 70% or less. Thereby, an effective dust collection area can be ensured and dust collection performance can be improved.
  • the equivalent diameter d of the cross section of the pipe dust collecting electrode 4B, 4C is set to 30 mm or more and 80 mm or less. Thereby, the dust collection performance of the dust collection electrode 4 can be improved.
  • one flat plate dust collecting part A is disposed on the upstream side, and two pipe dust collecting parts B and C are disposed on the downstream side thereof.
  • the flat plate dust collecting part is disposed on the upstream side.
  • the number of each dust collection parts is not limited to this embodiment. Therefore, the number of flat plate dust collecting parts A may be two or more, and the number of pipe dust collecting parts may be one or three or more.
  • the pipe dust collection electrodes 4B and 4C have been described as circular pipes, but the cross-sectional shape of the pipe dust collection electrodes 4B and 4C may be oval, oval, polygon or the like in addition to circular. You may use. Also, the dust collection electrode may be a solid instead of a hollow such as a pipe.
  • a flat dust collecting electrode 4D having an opening as shown in FIG. 10 may be used instead of the pipe dust collecting electrodes 4B and 4C of the present embodiment.
  • a dust collecting electrode 4E having a folded plate-shaped opening instead of the pipe dust collecting electrodes 4B and 4C of the present embodiment, a flat dust collecting electrode 4D having an opening as shown in FIG. 10 may be used.
  • a dust collection electrode 4E having a folded plate-shaped opening instead of the pipe dust collecting electrodes 4B and 4C of the present embodiment, a flat dust collecting electrode 4D having an opening as shown in FIG. 10 may be used.
  • FIG. 11 it may be a dust collection electrode 4E having a folded plate-shaped opening.
  • a mesh belt 4F having an opening may be used instead of the pipe dust collection electrode 4B, 4C.
  • the mesh belt is a flexible belt in which fine metal wires are knitted in a plane.
  • the mesh belt is endlessly wound around a plurality of rotating members (rotation drive rollers), and the mesh belt is appropriately moved between the gas flow path and the outside thereof. Dust attached to the mesh belt is removed by the brush outside the gas flow path.
  • a movable dust collection type of dust collection pole may have a predetermined opening, and is not limited to the mesh belt.
  • the electrostatic precipitator 1 of the present embodiment is not limited to a new one, and when the existing electrostatic precipitator has a plurality of flat plate dust collecting portions, the flat plate collection on the downstream side Instead of the dust portion, a pipe dust collection portion may be installed. By doing this, the electrostatic precipitator 1 of the present embodiment can be introduced at a lower cost than newly installed.

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Abstract

Provided is an electrostatic precipitator with improved dust collection efficiency for dust having a particle distribution. An electrostatic precipitator (1) is provided with: a flat plate dust collection unit (A) having a flat plate dust collecting electrode (4A) provided along a direction of gas flow G and formed in a plate shape without having an opening and a discharge electrode (5A) disposed parallel to the flat plate dust collecting electrode (4A); and pipe dust collection units (B, C) having pipe dust collecting electrodes (4B, 4C) disposed on the downstream side of the flat plate dust collection unit (4) in the direction of gas flow G and having an opening and discharge electrodes (5B, 5C) disposed parallel to the pipe dust collecting electrodes (4B, 4C).

Description

電気集塵装置Electric dust collector
　本発明は、電気集塵装置に関するものである。 The present invention relates to an electrostatic precipitator.
　従来の電気集塵装置として、ガス流れに沿って平行に配列された開口を有しない平板状の集塵極と、その中央に配列された鋭利な形状を有する放電極とを備えたものが知られている。 As a conventional electrostatic precipitator, it has been known that a flat dust collecting electrode having no opening arranged in parallel along the gas flow and a discharge electrode having a sharp shape arranged at the center thereof are known. It is done.
　電気集塵装置では、集塵極と放電極との間に直流高電圧を印加し、放電極に安定したコロナ放電を行うことで、ガス流れ中のダストを帯電させる。従来の集じん理論では、帯電したダストは放電極と集塵極との間の電界下でダストに作用するクーロン力の働きにより集塵極に捕集されると説明されている。 In the electrostatic precipitator, a high DC voltage is applied between the dust collection electrode and the discharge electrode to perform stable corona discharge on the discharge electrode, thereby charging dust in the gas flow. According to the conventional dust collection theory, charged dust is collected at the dust collection electrode by the action of the Coulomb force acting on the dust under an electric field between the discharge electrode and the dust collection electrode.
　ところで、特許文献１，２の電気集塵装置は、ダストを通過させるための複数の貫通孔を備え、内部にダストを捕集するための閉空間を有した集塵極を備えている。特許文献１，２では、貫通孔を介して閉空間にダストを閉じ込めることで捕集ダストが再飛散しにくくさせている。 By the way, the electrostatic precipitator of patent documents 1 and 2 is provided with a plurality of penetration holes for letting dust pass, and is provided with a dust collection pole which had a closed space for collecting dust inside. In Patent Documents 1 and 2, trapped dust is less likely to be scattered again by confining the dust in the closed space via the through holes.
　特許文献３の電気集塵装置は、６５％から８５％の開口率を有するアース電極と、ガスを捕集する集塵フィルタ層と、を含む集塵極を備えている。このような集塵極を備えることにより、特許文献３では、ガス流れと直交する断面内においてイオン風を発生させ、放電極と集塵極との間を循環するらせん状のガス流れを生成させ、ダストを効率よく捕集するようにしている。特許文献３では、イオン風を積極的に利用するが、ダストを主として集じんフィルタ層に捕集させることを目的としている。 The electrostatic precipitator of Patent Document 3 includes a dust collection electrode including an earth electrode having an aperture ratio of 65% to 85%, and a dust collection filter layer for collecting gas. By providing such a dust collection electrode, in Patent Document 3, an ion wind is generated in a cross section orthogonal to the gas flow to generate a spiral gas flow circulating between the discharge electrode and the dust collection electrode. , To collect dust efficiently. In patent document 3, although an ion wind is actively utilized, it aims at collecting dust mainly on a dust collection filter layer.
特許第５７６１４６１号公報Patent No. 5761461 gazette 特許第５７０５４６１号公報Patent No. 5705461 gazette 特許第４８２３６９１号公報Patent No. 4823691
　電気集塵装置における集塵効率ηは、よく知られた下記のドイチェの式（式（１））により算出することができる。ｗは、集塵性指数（粒子状物質の移動速度）、ｆは、単位ガス量当たりの集塵面積である。
　　η＝１－exp（－ｗ×ｆ）・・・（１） The dust collection efficiency η in the electrostatic precipitator can be calculated by the well-known German equation (equation (1)) below. w is a dust collection index (moving speed of particulate matter), and f is a dust collection area per unit gas amount.
η = 1-exp (-w × f) (1)
　上記式（１）において、ダスト（粒子状物質）の移動速度ｗは、クーロン力による力と、気体の粘性抵抗の関係で決まるとされている。ドイチェの式（上記式（１））では、ダストが放電極から電界中を移動するとされおり、イオン風は性能への影響においては直接考慮されていない。しかしながら、その性能設計の前提であるダスト濃度は、常に放電極と集塵極との間の集じん空間内では一様であるという前提条件があり、イオン風はガスの乱れを生じさせて、ダスト濃度を一様とさせる要因の一つとして考えられている。 In the above equation (1), the moving speed w of the dust (particulate matter) is determined to be determined by the relationship between the Coulomb force and the viscous drag of the gas. In the Deutsche equation (Eq. (1) above), dust is said to move from the discharge electrode in the electric field, and the ion wind is not directly considered in the influence on performance. However, the dust concentration, which is the premise of its performance design, has the precondition that it is always uniform in the dust collection space between the discharge electrode and the dust collection electrode, and the ion wind causes gas turbulence, It is considered as one of the factors that make the dust concentration uniform.
　イオン風は、電極間に負の電圧を印加した際に、放電極でコロナ放電によりマイナスイオンが発生し、その結果、生じるものであり、正の電圧の場合にはプラスのイオンにより生じる。以下、産業用の電気集塵装置をベースに考えるため、負の電圧を印加するケースについて記載するが、正であっても同様である。 The ion wind generates negative ions by corona discharge at the discharge electrode when a negative voltage is applied between the electrodes, and as a result, it is generated by positive ions in the case of a positive voltage. In the following, the case of applying a negative voltage is described in order to consider the industrial electrostatic precipitator as a base, but the same is true even if it is positive.
　放電極で生じたイオン風は、集塵極に向けて、ガス流れを横切るよう流れる。集塵極に達したイオン風は、集塵極で反転して流れ方向を変える。これにより、電極間にらせん状の乱流が生じる。 The ion wind generated by the discharge electrode flows across the gas flow toward the dust collection electrode. The ion wind that has reached the collecting electrode is reversed at the collecting electrode to change the flow direction. This causes a helical turbulence between the electrodes.
　乱流のうち、放電極から集塵極へと向かう流れは、ダストを集塵極近傍まで運ぶ作用がある。集塵極近傍まで運ばれたダストは、最終的にはクーロン力により捕集される。 Among the turbulent flows, the flow from the discharge electrode to the dust collection electrode has an effect of carrying dust to the vicinity of the dust collection electrode. The dust carried to the vicinity of the dust collection electrode is finally collected by the Coulomb force.
　しかしながら、集塵極で反転したイオン風の巻き戻しは、収集体である集塵極から離れる方向へとダストを移動させるため、集塵を阻害するような作用もある。
　特に、ガス中に含まれるダストは、所定の粒径分布を有しているため、比較的小さい粒径のダストは上述のようなイオン風の巻き戻しによる影響が大きく、捕集効率が上がらないおそれがある。 However, the rewinding of the ion wind reversed by the dust collection electrode moves dust in a direction away from the dust collection electrode that is the collecting body, and thus has an effect of inhibiting the dust collection.
In particular, since dust contained in the gas has a predetermined particle size distribution, relatively small particle size dust is largely affected by the unwinding of the ion wind as described above, and the collection efficiency does not increase. There is a fear.
　なお、特許文献３には、イオン風の効果も考慮した電気集塵装置を記載している。しかしながら、このケースでは、開口部を有する集塵極の背後にあるフィルタ層にイオン風を送り込む構造であり、主ガスの影響を受けない領域で集塵することを目的としていて、構造も複雑であること、及び、乾式ではフィルタ層に付着したダストの剥離回収が困難であった。 Patent Document 3 describes an electrostatic precipitator in consideration of the effect of ion wind. However, in this case, the structure is such that the ion wind is sent to the filter layer behind the dust collection electrode having the opening, and the structure is complicated in order to collect dust in a region not affected by the main gas. In some cases, it was difficult to separate and collect dust attached to the filter layer in the dry state.
　本開示は、このような事情に鑑みてなされたものであって、粒径分布を有するダストに対しても集塵効率を高めることのできる電気集塵装置を提供することを目的とする。 This indication is made in view of such a situation, and it aims at providing an electric dust collector which can raise dust collection efficiency also to dust which has particle size distribution.
　本開示の一態様に係る電気集塵装置は、ガス流れ方向に沿って設けられ、開口を有しない板状とされた第１集塵極と、該第１集塵極に対して並列に配置された第１放電極とを有する第１集塵部と、該第１集塵部のガス流れ方向の下流側に配置され、開口を有する第２集塵極と、該第２集塵極に対して並列に配置された第２放電極とを有する第２集塵部と、を備えている。 An electrostatic precipitator according to an aspect of the present disclosure is disposed in parallel to a first dust collection electrode which is provided along a gas flow direction and has no opening, and the first dust collection electrode. A first dust collection unit having a first discharge electrode, a second dust collection electrode disposed on the downstream side of the gas flow direction of the first dust collection unit, and an opening, and the second dust collection electrode And a second dust collection unit having a second discharge electrode arranged in parallel to each other.
　ガス流れの上流側に、開口を有しない板状とされた第１集塵極を有する第１集塵部を配置することによって、ガス中に含まれるダストのうち比較的粒径の大きなものを捕集する。また、第１集塵極は開口を有しないので、開口を設けない場合に比べて集塵面積が大きくなり多くのダストを捕集できる。
　第１集塵部のガス流れ方向の下流側に、開口を有する第２集塵極を有する第２集塵部を配置した。第２集塵極の開口を介して、第２放電極との間で生じるイオン風の一部を通過させることで、第２集塵極でイオン風が反転して離反する流れ（巻き戻し）を抑制する。これにより、イオン風によって比較的小さなダストでも第２集塵極の近傍まで導くことができ、第２集塵極の近傍ではクーロン力によって捕集することができる。よって、第１集塵部で捕集できなかった比較的小さなダストを下流側の第２集塵部で捕集することができる。
　このように、粒径分布を有するダストのうち比較的大きなダストを捕集することに適した第１集塵部と、比較的小さなダストを捕集することに適した第２集塵部とを組み合わせることで、所定の粒径分布を有するダストであっても効果的に捕集することができる。
　第２集塵極としては、例えば、所定間隔をおいて配列された円筒等の柱状体や、複数の開口を形成した平板ないし折板、金属メッシュなどが挙げられる。 By arranging the first dust collection unit having a plate-shaped first dust collection electrode without an opening on the upstream side of the gas flow, dust having a relatively large particle size among dust contained in the gas can be obtained. Collect. In addition, since the first dust collection electrode has no opening, the dust collection area can be increased and a large amount of dust can be collected as compared with the case where the opening is not provided.
The 2nd dust collection part which has the 2nd dust collection pole which has an opening in the downstream of the gas flow direction of the 1st dust collection part was arranged. A flow (rewinding) in which the ion wind reverses and separates at the second dust collection electrode by passing a part of the ion wind generated between itself and the second discharge electrode through the opening of the second dust collection electrode Suppress. Accordingly, even relatively small dust can be guided to the vicinity of the second dust collection electrode by the ion wind, and can be collected by the Coulomb force in the vicinity of the second dust collection electrode. Therefore, relatively small dust that could not be collected by the first dust collection unit can be collected by the second dust collection unit on the downstream side.
Thus, the first dust collection unit suitable for collecting relatively large dust among the dust having particle size distribution, and the second dust collection unit suitable for collecting relatively small dust By combining them, even dust having a predetermined particle size distribution can be effectively collected.
Examples of the second dust collection electrode include columnar bodies such as cylinders arranged at predetermined intervals, flat plates or folded plates having a plurality of openings, and metal mesh.
　さらに、本開示の一態様に係る電気集塵装置は、前記第２集塵極の開口率が、１０％以上７０％以下とされている。 Furthermore, in the electrostatic precipitator according to an aspect of the present disclosure, the aperture ratio of the second dust collection electrode is 10% or more and 70% or less.
　開口率が１０％未満となるとイオン風の離反抑制効果が低くなる。開口率が７０％を超えると有効な集塵面積が少なくなり集塵性を低下させる。
　開口率αは、等価直径をｄ、集塵極の中心間ピッチをＰｃとすると、以下のように表される。
　　　α＝１－（（ｄ×３．１４÷２）÷Ｐｃ）×１００　［％］ When the aperture ratio is less than 10%, the separation suppression effect of the ion wind is reduced. When the aperture ratio exceeds 70%, the effective dust collection area is reduced, and the dust collection performance is reduced.
The opening ratio α is expressed as follows, where the equivalent diameter is d and the center-to-center pitch of the collecting electrode is Pc.
α = 1 − ((d × 3.14 ÷ 2) ÷ Pc) × 100 [%]
　さらに、本開示の一態様に係る電気集塵装置では、前記第２集塵極は、前記ガス流れ方向に所定の間隔をあけて配置された複数の柱状体とされ、前記柱状体の横断面の等価直径は、３０ｍｍ以上８０ｍｍ以下とされている。 Furthermore, in the electrostatic precipitator according to one aspect of the present disclosure, the second dust collection electrode is a plurality of columnar bodies disposed at predetermined intervals in the gas flow direction, and a cross section of the columnar bodies The equivalent diameter of is 30 mm or more and 80 mm or less.
　柱状の第２集塵極を所定の間隔をあけて配置することで、放電部から集塵極へ向けて流れるイオン風の一部が集塵極の裏側へ抜けることを許容する。これにより、イオン風が集塵極で反転されて離反する流れ（巻き戻し）を抑制できる。
　注状体の横断面の等価直径を３０ｍｍ以上とした。等価直径を小さくすると電界集中が大きくなり集塵性は高まる。しかし、等価直径が小さくなりすぎると、集塵に必要な電流を確保したままでは電界強度のピーク値が大きくなり火花放電が生じる。このため、等価直径としての下限は３０ｍｍである。
　柱状体の横断面の等価直径を８０ｍｍ以下とした。等価直径が大きくなりすぎると、集塵極近傍における電界強度の持ち上がりが殆どなくなり、平板電極の平均電界強度程度になってしまう。また、等価直径が大きいとガス流れに対して渦を発生させてしまう。このため、等価直径としての上限は８０ｍｍである。
　等価直径とは、所定形状の横断面と等価な円形の直径を意味する。したがって、横断面が円形の場合は、その直径に相当する。
　柱状体としては、例えば円形断面とされたパイプ形状の部材が挙げられる。ただし、横断面形状としては、円形以外には、長円形、楕円形、多角形などが用いられる。また、集塵極としては中空だけでなく中実としても良い。 By arranging the columnar second dust collection electrode at a predetermined interval, a part of the ion wind flowing from the discharge portion toward the dust collection electrode is allowed to escape to the back side of the dust collection electrode. Thus, it is possible to suppress the flow (rewinding) in which the ion wind is reversed at the dust collection electrode and separated.
The equivalent diameter of the cross section of the cast body was 30 mm or more. When the equivalent diameter is reduced, the concentration of the electric field is increased and the dust collection property is enhanced. However, if the equivalent diameter is too small, the peak value of the electric field strength becomes large and spark discharge occurs while maintaining the current necessary for dust collection. For this reason, the lower limit as an equivalent diameter is 30 mm.
The equivalent diameter of the cross section of the columnar body was 80 mm or less. When the equivalent diameter is too large, the lifting of the electric field intensity in the vicinity of the dust collection electrode is hardly caused, and the average electric field intensity of the flat plate electrode will be about. In addition, if the equivalent diameter is large, a swirl is generated to the gas flow. For this reason, the upper limit as an equivalent diameter is 80 mm.
By equivalent diameter is meant a circular diameter equivalent to the cross section of a given shape. Thus, if the cross-section is circular, this corresponds to its diameter.
As a columnar body, the pipe-shaped member made into circular cross section, for example is mentioned. However, as the cross-sectional shape, in addition to the circular shape, an oval, an oval, a polygon or the like is used. In addition, not only hollow but also solid may be used as a dust collection electrode.
　開口を有しない板状とされた第１集塵極を有する第１集塵部と、第１集塵部の下流側に設けられ、開口を有する第２集塵極を有する第２集塵部とを組み合わせることで、粒径分布を有するダストに対しても集塵効率を高めることができる。 A second dust collection part having a first dust collection part having a plate-like first dust collection electrode not having an opening, and a second dust collection electrode provided on the downstream side of the first dust collection part and having an opening The dust collection efficiency can be enhanced also for dust having a particle size distribution by combining the
本開示の一実施形態に係る電気集塵装置を示した縦断面図である。BRIEF DESCRIPTION OF THE DRAWINGS It is the longitudinal cross-sectional view which showed the electrostatic precipitator which concerns on one Embodiment of this indication. パイプ部材とコロナ放電部との位置関係を示した横断面図である。It is a cross-sectional view which showed the positional relationship of a pipe member and a corona discharge part. コロナ放電部とパイプ部材との間の電気力線を示した横断面図である。It is a cross-sectional view which showed the electric line of force between a corona discharge part and a pipe member. パイプ部材の等価直径の下限を３０ｍｍとした根拠を示すグラフである。It is a graph which shows a ground which set the lower limit of the equivalent diameter of a pipe member to 30 mm. パイプ部材の等価直径の上限を８０ｍｍとした根拠を示すグラフである。It is a graph which shows a ground which set the upper limit of the equivalent diameter of a pipe member to 80 mm. パイプ集塵極の電界強度の持ち上がりを示したグラフである。It is the graph which showed the rise of electric field strength of the pipe dust collection pole. 平板集塵極の電界強度の持ち上がりを示したグラフである。It is the graph which showed the rise of the electric field strength of a flat plate dust collection pole. 集塵面積比を開口率に対して示したグラフである。It is the graph which showed the dust collection area ratio to the aperture ratio. ＥＰ効率を示したグラフである。It is the graph which showed EP efficiency. 集塵極の第１変形例を示した縦断面図である。It is the longitudinal cross-sectional view which showed the 1st modification of a dust collection pole. 集塵極の第２変形例を示した縦断面図である。It is the longitudinal cross-sectional view which showed the 2nd modification of a dust collection pole. 集塵極の第３変形例を示した正面図である。It is the front view which showed the 3rd modification of a dust collection pole.
　以下に、本開示に係る電気集塵装置の一実施形態について、図面を参照して説明する。 Hereinafter, an embodiment of an electrostatic precipitator according to the present disclosure will be described with reference to the drawings.
　電気集塵装置１は、例えば石炭等を燃料とする火力発電プラントに用いられ、ボイラから導かれた燃焼排ガス中のダスト（粒子状物質）を回収する。 The electrostatic precipitator 1 is used, for example, in a thermal power plant using coal as a fuel, and recovers dust (particulate matter) in combustion exhaust gas led from a boiler.
　図１には、本実施形態に係る電気集塵装置を上方から見た縦断面図が示されている。図１において、ガス流れＧは、水平流であり、紙面左側から右側に向けて流れる。 FIG. 1 shows a longitudinal sectional view of the electrostatic precipitator according to the present embodiment as viewed from above. In FIG. 1, the gas flow G is a horizontal flow, and flows from the left side to the right side of the drawing.
　電気集塵装置１は、ケーシング２内に、ガス流れＧに沿って、平板集塵部（第１集塵部）Ａと、上流側パイプ集塵部（第２集塵部）Ｂと、下流側パイプ集塵部（第２集塵部）Ｃとを備えている。 The electrostatic precipitator 1 includes, in the casing 2, a flat plate dust collection part (first dust collection part) A, an upstream pipe dust collection part (second dust collection part) B, and a gas flow G along the downstream side. And a side pipe dust collection unit (second dust collection unit) C.
　ケーシング２は、ガス入口部２ａと本体部２ｂとガス出口部２ｃとを備えている。ガス入口部２ａから流入したガスは、本体部２ｂへと導かれて各集塵部Ａ，Ｂ，Ｃで集塵された後に、ガス出口部２ｃから外部へと排出される。 The casing 2 includes a gas inlet 2a, a main body 2b, and a gas outlet 2c. The gas flowing in from the gas inlet 2a is guided to the main body 2b and collected by the dust collecting units A, B, and C, and then discharged from the gas outlet 2c to the outside.
　平板集塵部Ａは、ガス流れＧ方向に延在するように設けられた複数の平板集塵極４Ａと、平板集塵極４Ａに対して平行に離間して設けられた放電極５Ａとを備えている。 The flat plate collecting portion A includes a plurality of flat plate collecting electrodes 4A provided so as to extend in the gas flow G direction, and a discharge electrode 5A provided so as to be separated in parallel with the flat plate collecting electrodes 4A. Have.
　平板集塵極４Ａと放電極５Ａとは、互いに離隔され、電気的に絶縁されている。放電極５Ａはケーシング２とも絶縁されている。平板集塵極４Ａは接地され、放電極５Ａには負の極性を有する電源６Ａが接続されている。 The flat plate collecting electrode 4A and the discharge electrode 5A are separated from each other and electrically insulated. The discharge electrode 5A is also insulated from the casing 2. The flat plate collecting electrode 4A is grounded, and a power supply 6A having a negative polarity is connected to the discharge electrode 5A.
　各平板集塵極４Ａは、開口を有しない金属製の平板とされている。
　放電極５Ａは、取付基材７Ａと、複数のコロナ放電部８Ａとを有している。取付基材７Ａは、導電性を有する材質からなる棒状または板状の部材である。取付基材７Ａは、対面する平板集塵極４Ａに対して平行に配置されている。 Each flat plate collecting electrode 4A is a metal flat plate having no opening.
The discharge electrode 5A has a mounting base 7A and a plurality of corona discharge parts 8A. The mounting base 7A is a rod-like or plate-like member made of a conductive material. The mounting base 7A is disposed parallel to the facing flat plate collecting electrode 4A.
　コロナ放電部８Ａは、放電極５Ａに電圧が印加されることによって、コロナ放電を発生させるものである。コロナ放電部８Ａは、対面する平板集塵極４Ａに向かって突出するように取付基材７Ａに固定された突起とされ、先端が先細のトゲ状となっている。コロナ放電部８Ａは、紙面に直交する方向すなわち高さ方向に複数配置されている。 The corona discharge portion 8A generates a corona discharge by applying a voltage to the discharge electrode 5A. The corona discharge portion 8A is a protrusion fixed to the mounting base 7A so as to protrude toward the flat plate collecting electrode 4A facing the corona discharge portion 8A. A plurality of corona discharge portions 8A are disposed in the direction orthogonal to the paper surface, that is, in the height direction.
　上流側パイプ集塵部Ｂは、パイプ集塵極４Ｂと、取付基材７Ｂに固定された放電極５Ｂとを備えている。
　パイプ集塵極４Ｂは、複数のパイプ部材４Ｂａが所定間隔を有してガス流れＧの流通方向に並べられた離散式集塵極とされている。したがって、パイプ集塵極４Ｂは、開口を有するように設けられている。各パイプ部材４Ｂａは、剛性を有する金属製とされている。各パイプ部材４Ｂａは、軸線がガス流れＧに対して直交するように上下方向（紙面垂直方向）に向けて配置されている。ガス流れＧ方向に並んだ各パイプ部材４Ｂａ同士は、共通の枠体を用いてそれぞれを固定されている。 The upstream-side pipe dust collection unit B includes a pipe dust collection electrode 4B and a discharge electrode 5B fixed to the mounting base 7B.
The pipe dust collection electrode 4B is a discrete dust collection electrode in which a plurality of pipe members 4Ba are arranged in the flow direction of the gas flow G with a predetermined interval. Therefore, the pipe dust collection electrode 4B is provided to have an opening. Each pipe member 4Ba is made of rigid metal. Each pipe member 4Ba is arranged in the vertical direction (vertical direction in the drawing) so that the axis is orthogonal to the gas flow G. The pipe members 4Ba arranged in the gas flow G direction are fixed to each other using a common frame.
　放電極５Ｂは、平板集塵部Ａの放電極５Ａと同様の構成とされており、複数のコロナ放電部８Ｂを有している。各コロナ放電部８Ｂは、ガス流れＧ方向において、隣り合うパイプ部材４Ｂａの中央に位置するように配置されている。 The discharge electrode 5B has a configuration similar to that of the discharge electrode 5A of the flat plate dust collection part A, and has a plurality of corona discharge parts 8B. Each corona discharge portion 8B is disposed in the center of the adjacent pipe member 4Ba in the gas flow G direction.
　パイプ集塵極４Ｂと放電極５Ｂとは、互いに離隔され、電気的に絶縁されている。放電極５Ｂはケーシング２とも絶縁されている。パイプ集塵極４Ｂは接地され、放電極５Ｂには負の極性を有する電源６Ｂが接続されている。電源６Ｂは、平板集塵部Ａの電源６Ａとは異なる電圧が設定できるようになっている。 The pipe collecting electrode 4B and the discharging electrode 5B are separated from each other and electrically insulated. The discharge electrode 5B is also insulated from the casing 2. The pipe dust collecting electrode 4B is grounded, and a power supply 6B having a negative polarity is connected to the discharge electrode 5B. The power supply 6B can set a voltage different from that of the power supply 6A of the flat plate dust collection part A.
　下流側パイプ集塵部Ｃは、パイプ集塵極４Ｃと、取付基材７Ｃに固定された放電極５Ｃとを備えている。パイプ集塵極４Ｃは、上流側パイプ集塵部Ｂのパイプ集塵極４Ｂと同様の構成とされている。放電極５Ｃは、上流側パイプ集塵部Ｂの放電極５Ｂと同様の構成とされている。ただし、各パイプ部材４Ｃａの間隔や、各コロナ放電部８Ｃの間隔は、上流側パイプ集塵部Ｂのパイプ部材４Ｂａやコロナ放電部８Ｂの間隔と異なるものとしても良い。また、電源６Ｃは、平板集塵部Ａの電源６Ａや上流側パイプ集塵部Ｂの電源６Ｂとは異なる電圧が設定できるようになっている。 The downstream side pipe dust collection unit C includes a pipe dust collection electrode 4C and a discharge electrode 5C fixed to the mounting base 7C. The pipe dust collection electrode 4C has the same configuration as the pipe dust collection electrode 4B of the upstream side pipe dust collection unit B. The discharge electrode 5 </ b> C has a configuration similar to that of the discharge electrode 5 </ b> B of the upstream-side pipe dust collection unit B. However, the distance between the pipe members 4Ca and the distance between the corona discharge parts 8C may be different from the distance between the pipe members 4Ba of the upstream side pipe dust collection part B and the corona discharge parts 8B. Further, a voltage different from the power supply 6A of the flat plate dust collection part A and the power supply 6B of the upstream side pipe dust collection part B can be set as the power supply 6C.
　図２には、上流側パイプ集塵部Ｂ及び下流側パイプ集塵部Ｃのパイプ集塵極４Ｂ，４Ｃのパイプ部材４Ｂａ，４Ｃａとコロナ放電部８Ｂ，８Ｃとの位置関係が示されている。パイプ部材４Ｂａ，４Ｃａの中心間ピッチＰｃとコロナ放電部８Ｂ，８Ｃの中心間ピッチＰｄとを等しくすることが好ましい。そして、隣り合うパイプ部材４Ｂａ，４Ｃａ間に対向するようにコロナ放電部８Ｂ，８Ｃを配置することが好ましい。このように配置することで、図３に示すように、電気力線が各パイプ部材４Ｂａ，４Ｃａに均等に分配され、かつ、パイプ部材４Ｂａ，４Ｃａの円形とされた横断面のコロナ放電部８Ｂ，８Ｃから見て奥行き側まで電気力線を到達させることができる。なお、図２に示した符号Ｄは、パイプ部材４Ｂａ，４Ｃａとコロナ放電部８Ｂ，８Ｃとの直交方向（同図において上下方向）における距離であり、例えば１２５ｍｍ～２５０ｍｍとされている。 FIG. 2 shows the positional relationship between the pipe members 4Ba and 4Ca of the pipe dust collection electrodes 4B and 4C of the upstream side pipe dust collection part B and the downstream side pipe dust collection part C and the corona discharge parts 8B and 8C. . Preferably, the center-to-center pitch Pc of the pipe members 4Ba and 4Ca and the center-to-center pitch Pd of the corona discharge portions 8B and 8C are equal to each other. And it is preferable to arrange corona discharge parts 8B and 8C so as to be opposed between the adjacent pipe members 4Ba and 4Ca. By arranging in this manner, as shown in FIG. 3, the corona discharge portion 8B of the cross section of the pipe members 4Ba, 4Ca, in which the electric lines of force are equally distributed to the pipe members 4Ba, 4Ca , 8C can reach the electric force line to the depth side. The symbol D shown in FIG. 2 is the distance in the orthogonal direction (vertical direction in the figure) between the pipe members 4Ba and 4Ca and the corona discharge parts 8B and 8C, and is, for example, 125 mm to 250 mm.
　このようにパイプ部材４Ｂａ，４Ｃａの奥行きまで電気力線が到達することを考慮して、コロナ放電部８Ｂ，８Ｃ側からパイプ集塵極４Ｂ，４Ｃを正面視したときの開口率αは以下のように表される。
　　　α＝１－（（ｄ×３．１４÷２）÷Ｐｃ）×１００　［％］
　ここで、ｄはパイプ部材４Ｂａ，４Ｃａの等価直径である。等価直径とは、所定形状の横断面と等価な（同一面積を有する）円形の直径を意味する。したがって、本実施形態のようにパイプ部材４Ｂａ，４Ｃａの横断面が円形の場合は、その直径に相当する。
　開口率αは、１０％以上７０％以下とされている。その根拠については、後に図８を用いて説明する。 As described above, in view of the arrival of the electric field lines to the depths of the pipe members 4Ba and 4Ca, the opening ratio α when the pipe dust collection electrodes 4B and 4C are viewed in front from the corona discharge portions 8B and 8C is as follows: It is expressed as
α = 1 − ((d × 3.14 ÷ 2) ÷ Pc) × 100 [%]
Here, d is the equivalent diameter of the pipe members 4Ba and 4Ca. By equivalent diameter is meant the diameter of a circle (having the same area) equivalent to the cross section of a given shape. Therefore, when the cross section of pipe member 4Ba, 4Ca is circular like this embodiment, it corresponds to the diameter.
The aperture ratio α is set to 10% or more and 70% or less. The ground will be described later with reference to FIG.
　パイプ部材４Ｂａ，４Ｃａの等価直径ｄは、３０ｍｍ以上８０ｍｍ以下とされている。
　パイプ集塵極４Ｂ，４Ｃの横断面の等価直径ｄを３０ｍｍ以上とした理由は以下の通りである。等価直径ｄを小さくすると電界集中が大きくなり集塵性は高まる。しかし、等価直径ｄが小さくなりすぎると、図４に示すように、集塵に必要な電流密度（例えば０．３ｍＡ／ｍ２）を確保したままでは電界強度のピーク値が大きくなり火花電界強度の１０ｋＶ／ｃｍを超えて火花放電が生じる。このため、等価直径ｄとしての下限は３０ｍｍである。 The equivalent diameter d of the pipe members 4Ba and 4Ca is 30 mm or more and 80 mm or less.
The reason why the equivalent diameter d of the cross section of the pipe dust collecting electrode 4B, 4C is 30 mm or more is as follows. When the equivalent diameter d is reduced, the concentration of the electric field is increased and the dust collection property is enhanced. However, if the equivalent diameter d becomes too small, as shown in FIG. 4, the peak value of the electric field strength becomes large and the spark electric field strength if the current density (for example, 0.3 mA / m 2 ) necessary for dust collection is maintained. Spark discharge occurs over 10kV / cm of Therefore, the lower limit of the equivalent diameter d is 30 mm.
　パイプ部材４Ｂａ，４Ｃａの横断面の等価直径ｄを８０ｍｍ以下とした理由は以下の通りである。等価直径ｄが大きくなりすぎると、パイプ部材４Ｂａ，４Ｃａの近傍における電界強度の持ち上がり（後に図６を用いて説明する。）が殆どなくなり、穴のない平板集塵極４Ａの平均電界強度（２ｋＶ／ｃｍ）程度になってしまう。また、等価直径ｄが大きいとガス流れに対して影響を及ぼし渦を発生させてしまう。このため、等価直径ｄとしての上限は８０ｍｍである。例えば、上記と同じ条件で算出される等価直径ｄが３０ｍｍのときの平均電界強度は５．７ｋＶ／ｃｍである。
　なお、図５の縦軸は平均電界強度とされており、パイプ集塵極４Ｂ，４Ｃの表面積で平均化した電界強度である。この平均電界強度は、図４の縦軸のピーク電界強度とは異なる。ピーク電界強度は、パイプ集塵極４Ｂ，４Ｃの表面のうち最も電界強度が高い位置における電界強度である。 The reason for setting the equivalent diameter d of the cross sections of the pipe members 4Ba and 4Ca to 80 mm or less is as follows. If the equivalent diameter d is too large, the increase of the electric field intensity in the vicinity of the pipe members 4Ba and 4Ca (to be described later with reference to FIG. 6) is almost eliminated, and the average electric field intensity of the flat plate collecting electrode 4A without holes (2 kV It becomes about / cm). In addition, if the equivalent diameter d is large, the gas flow is affected and a vortex is generated. Therefore, the upper limit of the equivalent diameter d is 80 mm. For example, the average electric field strength when the equivalent diameter d is 30 mm calculated under the same conditions as described above is 5.7 kV / cm.
The vertical axis in FIG. 5 is the average electric field strength, which is the electric field strength averaged over the surface area of the pipe dust collecting electrodes 4B and 4C. This average electric field strength is different from the peak electric field strength on the vertical axis of FIG. The peak electric field strength is the electric field strength at the position of the highest electric field strength among the surfaces of the pipe dust collecting electrodes 4B and 4C.
　次に、図６を用いて、パイプ集塵極４Ｂ，４Ｃのパイプ部材４Ｂａ，４Ｃａの近傍の電界強度の持ち上がりについて説明する。同図に示すように、横軸が位置を示しており、ｙ軸に相当する位置にコロナ放電部８Ｂ，８Ｃが位置しているものとする。縦軸は電界強度である。電界強度は、コロナ放電部８Ｂ，８Ｃの位置で最も高くなり、パイプ部材４Ｂａ，４Ｃａとの間で極小値をとった後に、再びパイプ部材４Ｂａ，４Ｃａに向かいながら増大する。パイプ部材４Ｂａ，４Ｃａの近傍では、電界強度の増加率（傾き）が大きい領域Ｚ１が存在する。これは、パイプ部材４Ｂａ，４Ｃａの近傍はダストやマイナスイオンが有する空間電荷の影響で電界強度が高くなるからである。この領域Ｚ１における電界強度の増大を“電界強度の持ち上がり”という。領域Ｚ１ではクーロン力が支配的となる領域となり、パイプ部材４Ｂａ，４ＣａにおけるダストＰの集塵が効果的に行われる。 Next, with reference to FIG. 6, the lifting of the electric field strength in the vicinity of the pipe members 4Ba and 4Ca of the pipe dust collection electrodes 4B and 4C will be described. As shown in the figure, the horizontal axis indicates the position, and it is assumed that the corona discharge parts 8B and 8C are located at the position corresponding to the y axis. The vertical axis is the electric field strength. The electric field strength is highest at the positions of the corona discharge parts 8B and 8C, and after increasing the local value between the pipe members 4Ba and 4Ca, increases while going to the pipe members 4Ba and 4Ca again. In the vicinity of the pipe members 4Ba and 4Ca, there is a region Z1 in which the rate of increase (inclination) of the electric field strength is large. This is because the electric field strength in the vicinity of the pipe members 4Ba and 4Ca is increased due to the space charge of dust and negative ions. The increase of the electric field strength in the region Z1 is referred to as "lifting of the electric field strength". In the region Z1, the Coulomb force becomes dominant, and dust collection of the dust P in the pipe members 4Ba and 4Ca is effectively performed.
　領域Ｚ１よりもコロナ放電部８Ｂ，８Ｃ側の領域Ｚ２は、イオン風の支配領域とされる。領域Ｚ２では、ガス中のダストＰは主としてイオン風に伴ってパイプ部材４Ｂａ，４Ｃａへと導かれる。 A region Z2 closer to the corona discharge portions 8B and 8C than the region Z1 is a dominant region of the ion wind. In the area Z2, the dust P in the gas is led to the pipe members 4Ba and 4Ca mainly along with the ion wind.
　図７には、穴（開口）なしの平板集塵極４Ａを用いた場合の電界強度が示されている。同図から分かるように、平板集塵極４Ａ近傍における電界強度の絶対値は、図６に示したパイプ部材４Ｂａ，４Ｃａよりも小さく、電界強度の持ち上がりも小さい。したがって、パイプ集塵極４Ｂ，Ｃよりも集塵性能が劣ることが分かる。ただし、イオン風の影響が少ない比較的大きなダストに対しては、平板集塵極４Ａであっても十分な捕集性能を発揮する。 FIG. 7 shows the electric field strength in the case of using the flat plate collecting electrode 4A without the holes (openings). As can be seen from the figure, the absolute value of the electric field intensity in the vicinity of the flat plate dust collection electrode 4A is smaller than that of the pipe members 4Ba and 4Ca shown in FIG. Therefore, it is understood that the dust collection performance is inferior to the pipe dust collection electrodes 4B and 4C. However, even for the flat dust collection electrode 4A, sufficient collection performance is exhibited with respect to relatively large dust less affected by the ion wind.
　図８には、開口率αに対する集塵面積比が示されている。集塵面積比は、平板集塵極４Ａのように開口率０％（隙間がない場合）のときの集塵性能を１とした場合に、同じ集塵性能を発揮する場合の集塵面積を示すものである。したがって、集塵面積比は、小さいほど捕集効率が高いことを示す。 FIG. 8 shows the dust collection area ratio to the opening ratio α. The dust collection area ratio is the dust collection area when exhibiting the same dust collection performance when the dust collection performance at an aperture ratio of 0% (in the case of no gap) is 1 as in the flat plate dust collection electrode 4A. It is shown. Therefore, the smaller the dust collection area ratio, the higher the collection efficiency.
　図８に示されているように、開口率αが１０％以上７０％以下の場合に集塵面積比が０．８以下となる。したがって、開口率αは１０％以上７０％以下（適用範囲）が好ましい。 As shown in FIG. 8, when the opening ratio α is 10% or more and 70% or less, the dust collection area ratio is 0.8 or less. Therefore, the aperture ratio α is preferably 10% to 70% (application range).
　電気集塵装置１には、図示しないが、集塵極４Ａ，４Ｂ，４Ｃに付着した粒子状物質を剥離するための槌打装置が設けられている。槌打装置はハンマを有しており、ハンマが集塵極４Ａ，４Ｂ，４Ｃを槌打することで、表面に付着したダストを振動によって剥離除去する。
　なお、ダストの集塵極４Ａ，４Ｂ，４Ｃからの除去方法は、槌打装置を用いた槌打に限定されない。例えば、集塵極４Ａ，４Ｂ，４Ｃに捕集されたダストに対しガスを吹き付ける方法、又は、ソニック・ホーンを用いて音波を照射する方法によって、ダストを集塵極４Ａ，４Ｂ，４Ｃから除去してもよい。また、湿式の電気集塵装置で行われている洗浄液による洗浄によって、集塵極４Ａ，４Ｂ，４Ｃから粒子状物質を除去してもよい。 Although not shown in the figure, the electrostatic precipitator 1 is provided with a striking device for peeling off the particulate matter adhering to the dust collection electrodes 4A, 4B, 4C. The beating apparatus has a hammer, and the hammer strikes on the dust collection electrodes 4A, 4B, 4C to separate and remove dust attached to the surface by vibration.
Note that the method of removing dust from the dust collection electrodes 4A, 4B, 4C is not limited to beating using a beating apparatus. For example, dust is removed from the dust collection electrodes 4A, 4B, 4C by a method of blowing a gas to dust collected on the collection electrodes 4A, 4B, 4C, or a method of irradiating sound waves using a sonic horn You may In addition, the particulate matter may be removed from the dust collection electrodes 4A, 4B, 4C by cleaning with a cleaning liquid performed by a wet type electrostatic precipitator.
　次に、本実施形態の電気集塵装置１の動作を説明する。
　電気集塵装置１では、放電極５Ａ，５Ｂ，５Ｃに電圧を印加することで、コロナ放電部８Ａ，８Ｂ，８Ｃの先端でコロナ放電が発生する。ガス流れＧに含まれるダストは、コロナ放電により帯電される。 Next, the operation of the electrostatic precipitator 1 of the present embodiment will be described.
In the electrostatic precipitator 1, by applying a voltage to the discharge electrodes 5A, 5B, 5C, corona discharge occurs at the tip of the corona discharge parts 8A, 8B, 8C. The dust contained in the gas stream G is charged by corona discharge.
　平板集塵部Ａでは、帯電されたダストは集じん極に向かって流れるイオン風により集じん極の近傍まで移動し、その後、平板集塵極４Ａ近傍でクーロン力によって引き寄せられて捕集される。捕集されるダストは、粒径分布を有するダストのうち比較的粒径の大きなダストが優先的に捕集される。これは、粒径が大きなダストの方が粒径の小さなダストに比べて表面積が大きく粒径に比例して空気抵抗が大きくなる一方、粒径の２乗に比例して帯電量が多くなりクーロン力の効果が大きくなるため、結果として移動速度が増加するためである。粒径の大きいダストはイオン風の影響を受けにくいため、開口部を持たない集じん極でもイオン風の巻き戻しによる影響が少ない。 In the flat plate collecting portion A, the charged dust moves to the vicinity of the collecting electrode by the ion wind flowing toward the collecting electrode, and is then attracted and collected near the flat collecting electrode 4A by the Coulomb force . Among the dusts having a particle size distribution, dusts having relatively large particle sizes are preferentially collected. This is because dust with a larger particle size has a larger surface area and larger air resistance in proportion to the particle size than dust with a smaller particle size, while the amount of charge increases in proportion to the square of the particle size, resulting in coulombs This is because the movement speed increases as the effect of force increases. Since dust with a large particle size is not easily affected by the ion wind, there is little influence by the unwinding of the ion wind even at a dust collection electrode without an opening.
　一方、パイプ集塵部Ｂ，Ｃでは、上流側で粒径の粗いダストが除去されるために比較的粒径の小さなダストが優先的に捕集される。パイプ集塵極４Ｂ，４Ｃに向かって流れるイオン風は、ダストをパイプ集塵極４Ｂ，４Ｃの近傍まで移動させるように作用する。その後ダストは、パイプ集じん極近傍でクーロン力によって引き寄せられて捕集されるが、粒子径が小さいダストの場合、イオン風の影響を受けやすいため、開口部を持つパイプ集じん部にすることでイオン風の巻き戻しによる影響が少なくなり、開口部がない場合に比べて捕集効率が向上する。さらに、パイプ集塵極４Ｂ，４Ｃの近傍の領域Ｚ１（図６参照）では、電界強度の持ち上がりが大きいので効果的にダストを集塵する。 On the other hand, in the pipe dust collection sections B and C, relatively large particle size dust is preferentially collected because upstream side particles having coarse particle size are removed. The ion wind flowing toward the pipe collecting electrodes 4B, 4C acts to move the dust to the vicinity of the pipe collecting electrodes 4B, 4C. After that, the dust is attracted and collected by the Coulomb force in the vicinity of the pipe dust collection pole, but in the case of dust with small particle size, it is easily affected by the ion wind, so use a pipe dust collection part with an opening In this case, the influence of the unwinding of the ion wind is reduced, and the collection efficiency is improved as compared with the case without the opening. Furthermore, in the area Z1 (see FIG. 6) in the vicinity of the pipe dust collection electrodes 4B and 4C, dust is effectively collected because the lifting of the electric field strength is large.
　図９には、電気集塵装置１によるダストの捕集効率（ＥＰ効率）が示されている。同図において、横軸は、ガス流れＧ方向の位置を示す。したがって、上流側に平板集塵部Ａが位置し、その下流側にパイプ集塵部Ｂ，Ｃが位置している。
　平板集塵部ＡのＥＰ効率は、ガス流れＧの上流側では多くの比較的大きなダストを捕集するので良好な捕集効率を示すが、ガス流れＧの下流側に行くに従い比較的小さなダストが相対的に多くなるので捕集効率が頭打ちになる。
　パイプ集塵部Ｂ、ＣのＥＰ効率は、上流側では比較的大きなダストが多く存在するので、平板集塵部Ａほど良好ではない。しかし、ガス流れＧの下流側に行くに従い比較的小さなダストが相対的に多くなるので、平板集塵部Ａよりも良好なＥＰ効率を示す。
　したがって、電気集塵装置１の全体的なＥＰ効率は、一点鎖線で示すように、ガス流れＧの上流側および下流側で良好な値を示す。 FIG. 9 shows the dust collection efficiency (EP efficiency) by the electrostatic precipitator 1. In the figure, the horizontal axis indicates the position in the gas flow G direction. Therefore, the flat plate dust collection part A is positioned upstream, and the pipe dust collection parts B and C are positioned downstream thereof.
The EP efficiency of the flat-plate dust collection part A shows a good collection efficiency because it collects a large amount of relatively large dust on the upstream side of the gas flow G, but as the downstream side of the gas flow G is relatively small dust The collection efficiency becomes relatively flat because the
The EP efficiency of the pipe dust collecting parts B and C is not as good as that of the flat sheet dust collecting part A because a relatively large amount of dust is present on the upstream side. However, since relatively small dust relatively increases toward the downstream side of the gas flow G, EP efficiency better than that of the flat plate dust collection part A is exhibited.
Therefore, the overall EP efficiency of the electrostatic precipitator 1 exhibits good values on the upstream side and the downstream side of the gas flow G, as indicated by the one-dot and dash line.
　本実施形態によれば、以下の作用効果を奏する。
　ガス流れＧの上流側に、開口を有しない板状とされた平板集塵極４Ａを有する平板集塵部Ａを配置することによって、ガス中に含まれるダストのうち比較的大きなものを捕集する。また、平板集塵極４Ａは開口を有しないので集塵面積が大きくなり多くのダストを捕集できる。
　平板集塵部Ａのガス流れＧ方向の下流側に、開口を有するパイプ集塵極４Ｂ，４Ｃを有するパイプ集塵部Ｂ，Ｃを配置した。パイプ集塵極４Ｂ，４Ｃの開口を介して、放電極５Ｂ，５Ｃとの間で生じるイオン風の一部を通過させることで、パイプ集塵極４Ｂ，４Ｃでイオン風が反転して離反する流れ（巻き戻し）を抑制する。これにより、イオン風によって比較的小さなダストでもパイプ集塵極４Ｂ，４Ｃの近傍まで導くことができ、パイプ集塵極４Ｂ，４Ｃの近傍ではクーロン力によって捕集することができる。よって、平板集塵部Ａで捕集できなかった比較的小さなダストを下流側のパイプ集塵部Ｂ，Ｃで捕集することができる。
　このように、粒径分布を有するダストのうち比較的大きなダストを捕集することに適した平板集塵部Ａと、比較的小さなダストを捕集することに適したパイプ集塵部Ｂ，Ｃとを組み合わせることで、所定の粒径分布を有するダストであっても効果的に捕集することができる。 According to the present embodiment, the following effects are achieved.
By arranging the flat plate dust collection part A having the flat plate dust collection electrode 4A in the form of a plate having no opening on the upstream side of the gas flow G, relatively large dust contained in the gas is collected Do. Further, since the flat plate dust collection electrode 4A does not have an opening, the dust collection area becomes large and a large amount of dust can be collected.
On the downstream side of the flat plate dust collection part A in the gas flow G direction, pipe dust collection parts B and C having pipe collection electrodes 4B and 4C having openings are disposed. By passing a part of the ion wind generated between the discharge electrodes 5B and 5C through the openings of the pipe dust collection electrodes 4B and 4C, the ion wind is inverted and separated at the pipe dust collection electrodes 4B and 4C. Suppress the flow (rewind). Thereby, even relatively small dust can be guided to the vicinity of the pipe dust collection electrodes 4B and 4C by the ion wind, and can be collected by the Coulomb force in the vicinity of the pipe dust collection electrodes 4B and 4C. Therefore, relatively small dust which could not be collected by the flat plate dust collection part A can be collected by the pipe dust collection parts B and C on the downstream side.
Thus, the flat plate dust collection part A suitable for collecting relatively large dust among the dust having particle size distribution and the pipe dust collection parts B and C suitable for collecting relatively small dust By combining these, even dust having a predetermined particle size distribution can be effectively collected.
　パイプ集塵極４Ｂ，４Ｃの開口率αを１０％以上７０％以下とした。これにより、有効な集塵面積を確保して集塵性能を向上させることができる。 The opening ratio α of the pipe dust collection electrodes 4B and 4C is set to 10% or more and 70% or less. Thereby, an effective dust collection area can be ensured and dust collection performance can be improved.
　パイプ集塵極４Ｂ，４Ｃの横断面の等価直径ｄを３０ｍｍ以上８０ｍｍ以下とした。これにより、集塵極４の集塵性能を向上させることができる。 The equivalent diameter d of the cross section of the pipe dust collecting electrode 4B, 4C is set to 30 mm or more and 80 mm or less. Thereby, the dust collection performance of the dust collection electrode 4 can be improved.
　なお、本実施形態では、１つの平板集塵部Ａを上流側に配置し、その下流側に２つのパイプ集塵部Ｂ，Ｃを配置することとしたが、上流側に平板集塵部が配置され、その下流側にパイプ集塵部が配置されていれば良く、それぞれの集塵部の数は本実施形態に限定されるものではない。したがって、平板集塵部Ａが２つ以上でも良く、パイプ集塵部が１つでも３つ以上でも良い。 In the present embodiment, one flat plate dust collecting part A is disposed on the upstream side, and two pipe dust collecting parts B and C are disposed on the downstream side thereof. However, the flat plate dust collecting part is disposed on the upstream side. As long as it arrange | positions and the pipe | tube dust collection part is arrange | positioned downstream, the number of each dust collection parts is not limited to this embodiment. Therefore, the number of flat plate dust collecting parts A may be two or more, and the number of pipe dust collecting parts may be one or three or more.
　また、本実施形態では、パイプ集塵極４Ｂ，４Ｃとして円形パイプとして説明したが、パイプ集塵極４Ｂ，４Ｃの横断面形状としては、円形以外に、長円形、楕円形、多角形などを用いても良い。また、集塵極としてはパイプのような中空に代えて中実としても良い。 Further, in the present embodiment, the pipe dust collection electrodes 4B and 4C have been described as circular pipes, but the cross-sectional shape of the pipe dust collection electrodes 4B and 4C may be oval, oval, polygon or the like in addition to circular. You may use. Also, the dust collection electrode may be a solid instead of a hollow such as a pipe.
　また、本実施形態のパイプ集塵極４Ｂ，４Ｃに代えて、図１０に示すような開口を有する平板状の集塵極４Ｄとしても良い。あるいは、図１１に示すように、折板形状とした開口を有する集塵極４Ｅとしても良い。 Further, instead of the pipe dust collecting electrodes 4B and 4C of the present embodiment, a flat dust collecting electrode 4D having an opening as shown in FIG. 10 may be used. Alternatively, as shown in FIG. 11, it may be a dust collection electrode 4E having a folded plate-shaped opening.
　また、パイプ集塵極４Ｂ，４Ｃに代えて、図１２に示すように、開口を有するメッシュベルト４Ｆを用いても良い。メッシュベルトは、金属細線を面状に編み込んだ可撓性を有するものである。メッシュベルトを無端状にして複数の回転部材（回転駆動ローラ）に巻回し、メッシュベルトをガス流路とその外側との間で適宜移動させるように構成する。メッシュベルトに付着したダストは、ガス流路の外側にてブラシによって除去される。このような移動集じん極方式の集じん極は、所定の開口があいていれば良く、メッシュベルトに限定されない。 Further, as shown in FIG. 12, a mesh belt 4F having an opening may be used instead of the pipe dust collection electrode 4B, 4C. The mesh belt is a flexible belt in which fine metal wires are knitted in a plane. The mesh belt is endlessly wound around a plurality of rotating members (rotation drive rollers), and the mesh belt is appropriately moved between the gas flow path and the outside thereof. Dust attached to the mesh belt is removed by the brush outside the gas flow path. Such a movable dust collection type of dust collection pole may have a predetermined opening, and is not limited to the mesh belt.
　また、本実施形態の電気集塵装置１は、新設のものに限定されるものではなく、既設の電気集塵装置が複数の平板集塵部を有している場合に、下流側の平板集塵部に代えてパイプ集塵部を設置するようにしても良い。このようにすることで、新設よりも安価に本実施形態の電気集塵装置１を導入することができる。 In addition, the electrostatic precipitator 1 of the present embodiment is not limited to a new one, and when the existing electrostatic precipitator has a plurality of flat plate dust collecting portions, the flat plate collection on the downstream side Instead of the dust portion, a pipe dust collection portion may be installed. By doing this, the electrostatic precipitator 1 of the present embodiment can be introduced at a lower cost than newly installed.
１　電気集塵装置
２　ケーシング
４Ａ　平板集塵極
４Ｂ，４Ｃ　パイプ集塵極
４Ｂａ，４Ｃａ　パイプ部材
５Ａ，５Ｂ，５Ｃ　放電極
６Ａ，６Ｂ，６Ｃ　電源
７Ａ，７Ｂ，７Ｃ　取付基材
８Ａ，８Ｂ，８Ｃ　コロナ放電部
Ａ　平板集塵部（第１集塵部）
Ｂ　上流側パイプ集塵部（第２集塵部）
Ｃ　下流側パイプ集塵部（第２集塵部）
α　開口率
ｄ　等価直径 DESCRIPTION OF SYMBOLS 1 Electric dust collector 2 Casing 4A Flat plate collection electrode 4B, 4C Pipe collection electrode 4Ba, 4Ca Pipe member 5A, 5B, 5C Discharge electrode 6A, 6B, 6C Power supply 7A, 7B, 7C Mounting base material 8A, 8B, 8C Corona discharge part A Flat plate dust collection part (1st dust collection part)
B upstream pipe dust collection part (second dust collection part)
C downstream pipe dust collection part (second dust collection part)
α aperture ratio d equivalent diameter

Claims (3)

  1. 　ガス流れ方向に沿って設けられ、開口を有しない板状とされた第１集塵極と、該第１集塵極に対して並列に配置された第１放電極とを有する第１集塵部と、
    　該第１集塵部のガス流れ方向の下流側に配置され、開口を有する第２集塵極と、該第２集塵極に対して並列に配置された第２放電極とを有する第２集塵部と、
    を備えている電気集塵装置。     A first dust collection provided with a plate-like first dust collection electrode provided along a gas flow direction and having no opening, and a first discharge electrode arranged in parallel to the first dust collection electrode Department,
    A second dust collection electrode disposed downstream of the first dust collection portion in the gas flow direction and having a second discharge electrode, and a second discharge electrode arranged parallel to the second dust collection electrode. A dust collection unit,
    Electric dust collector equipped with.
  2. 　前記第２集塵極の開口率が、１０％以上７０％以下とされている請求項１に記載の電気集塵装置。 The electrostatic precipitator according to claim 1, wherein an aperture ratio of the second dust collection electrode is 10% or more and 70% or less.
  3. 　前記第２集塵極は、前記ガス流れ方向に所定の間隔をあけて配置された複数の柱状体とされ、
    　前記柱状体の横断面の等価直径は、３０ｍｍ以上８０ｍｍ以下とされている請求項１又は２に記載の電気集塵装置。     The second dust collection electrode is formed of a plurality of columnar bodies disposed at predetermined intervals in the gas flow direction,
    The electrostatic precipitator according to claim 1 or 2, wherein an equivalent diameter of a cross section of the columnar body is set to 30 mm or more and 80 mm or less.
PCT/JP2018/046415 2018-01-18 2018-12-17 Electrostatic precipitator WO2019142573A1 (en)

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JP7358216B2 (en) * 2019-11-29 2023-10-10 三菱重工パワー環境ソリューション株式会社 electrostatic precipitator

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07155641A (en) * 1993-12-06 1995-06-20 Sumitomo Heavy Ind Ltd Electrostatic precipitator
JP2000140690A (en) * 1998-11-06 2000-05-23 Mitsubishi Heavy Ind Ltd Dry type dust collector
CN102172564A (en) * 2010-12-24 2011-09-07 刘燕芳 Revolving body electrode and heterogeneous separation device based on same
JP2016073954A (en) * 2014-10-08 2016-05-12 三菱日立パワーシステムズ環境ソリューション株式会社 Electric dust collector

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07155641A (en) * 1993-12-06 1995-06-20 Sumitomo Heavy Ind Ltd Electrostatic precipitator
JP2000140690A (en) * 1998-11-06 2000-05-23 Mitsubishi Heavy Ind Ltd Dry type dust collector
CN102172564A (en) * 2010-12-24 2011-09-07 刘燕芳 Revolving body electrode and heterogeneous separation device based on same
JP2016073954A (en) * 2014-10-08 2016-05-12 三菱日立パワーシステムズ環境ソリューション株式会社 Electric dust collector

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