JP6953605B2

JP6953605B2 - Electrostatic precipitator

Info

Publication number: JP6953605B2
Application number: JP2020203709A
Authority: JP
Inventors: 一隆富松; 加藤　雅也; 雅也加藤; 上田　泰稔; 泰稔上田
Original assignee: Mitsubishi Power Environmental Solutions Ltd
Current assignee: Mitsubishi Power Environmental Solutions Ltd
Priority date: 2018-08-15
Filing date: 2020-12-08
Publication date: 2021-10-27
Anticipated expiration: 2039-04-24
Also published as: JP2020028876A; PH12021550311A1; CN112566727A; JP7106491B2; JP2021037513A; CN112566727B

Description

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平板状の集塵極と、その中央に配列されたコロナ放電部を有する放電極とを備えたものが知られている。放電極のコロナ放電部の形状には、突起形状を持たせて電界の集中を生じさせることでコロナ放電を確保する方式と、放電極本体を一様な電界集中を生じさせる構造、例えば角線や細いピアノ線などがあるが、一般産業用の電気集塵装置では、電極が汚れても安定したコロナ放電を確保するため、突起状のコロナ放電部を有した構造が主流であり、以降この構造を前提とする。 As a conventional electrostatic precipitator, a device including a flat plate-shaped dust collecting electrode arranged in parallel along a gas flow and a discharge electrode having a corona discharge portion arranged in the center thereof is known. The shape of the corona discharge part of the discharge electrode is a method that secures the corona discharge by giving a protrusion shape and causing the concentration of the electric field, and a structure that causes the discharge electrode body to generate a uniform electric field concentration, for example, a square wire. There are thin piano wires, etc., but in general industrial electrostatic collectors, in order to ensure stable corona discharge even if the electrodes are dirty, a structure with a protruding corona discharge part is the mainstream. The structure is assumed.

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、放電極のコロナ放電部で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。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、従来の集じん理論では説明されている。 In the electrostatic precipitator, a high DC voltage is applied between the dust collecting electrode and the discharge electrode, and stable corona discharge is performed at the corona discharge portion of the discharge electrode to charge the dust in the gas flow. It is explained in the conventional dust collection theory that the charged dust is collected in the dust collection electrode by the action of the Coulomb force acting on the dust under the 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、該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 precipitators of Patent Documents 1 and 2 are provided with a plurality of through holes for passing dust, and are provided with a dust collecting electrode having a closed space for collecting dust inside. In Patent Documents 1 and 2, the collected dust is hard to be scattered again by confining the dust in the closed space through the through hole.

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、本ケースはダストを、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 collecting electrode including an earth electrode having an aperture ratio of 65% to 85% and a dust collecting filter layer for collecting gas. By providing such a dust collecting electrode, in Patent Document 3, an ionic wind is generated in a cross section orthogonal to the gas flow, and a spiral gas flow circulating between the discharge electrode and the dust collecting electrode is generated. , I try to collect dust efficiently. In Patent Document 3, ionic wind is actively used, but the purpose of this case is to collect dust mainly in the dust collection filter layer.

特許第５７６１４６１号公報Japanese Patent No. 5761461 特許第５７０５４６１号公報Japanese Patent No. 5705461 特許第４８２３６９１号公報Japanese 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数式（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 following well-known Deutsche's mathematical formula (Equation (1)). w is the dust collection index (movement speed of particulate matter), and f is the 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。ドイチェの数式（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ており、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の分布は、常に電気集塵装置のガス流れに直交した放電極と集塵極との間の集じん空間の断面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 formula (1), the moving speed w of dust (particulate matter) is determined by the relationship between the force due to Coulomb force and the viscous resistance of gas. According to Deutsche's formula (formula (1) above), dust moves from the release electrode in the electric field, and ion wind is not directly considered in terms of its effect on performance. However, the precondition that the distribution of the dust concentration, which is the premise of the performance design, is always uniform within the cross section of the dust collection space between the discharge electrode and the dust collection electrode orthogonal to the gas flow of the electrostatic precipitator. Ion wind is considered to be one of the factors that cause gas turbulence and 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、本明細書では、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。 When a negative voltage is applied between the electrodes, the ionic wind generates negative ions due to corona discharge at the discharge electrode, and as a result, it is generated, and in the case of a positive voltage, it is generated by positive ions. Hereinafter, in this specification, a case where a negative voltage is applied will be described in order to consider based on an industrial electrostatic precipitator, but the same applies even if it is positive.

ガス流れに沿って電極群が配置されている電気集塵装置では、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。 In an electrostatic precipitator in which a group of electrodes is arranged along the gas flow, the ionic wind generated at the discharge electrode flows toward the dust collecting electrode and crosses the gas flow. The ionic wind that has reached the dust collecting electrode reverses at the dust collecting electrode and changes the flow direction. This creates a spiral 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。 Of the turbulent flow, the flow from the discharge electrode to the dust collecting electrode has the effect of carrying dust to the vicinity of the dust collecting electrode. The dust carried to the vicinity of the dust collection electrode is finally collected by Coulomb force.

しかしながら、集塵極で反転したイオン風は、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。そのため、集塵極に開口部を設け、イオン風の反転を防ぐ手段が有効である。 However, the ion wind inverted at the dust collecting electrode moves the dust away from the dust collecting electrode, which is a collector, and therefore has an action of inhibiting dust collection. Therefore, it is effective to provide an opening in the dust collecting electrode to prevent the reversal of the ionic wind.

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が記載されている。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箇所での集じんをすることを目的としていて、構造も複雑であること、及び、乾式では付着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 ionic wind. However, in this case, the structure is such that ion air is sent to the filter layer behind the dust collecting electrode having an opening, and the purpose is to collect dust in a place that is not affected by the main gas, and the structure is also It was complicated, and it was difficult to remove and recover the adhered dust by the dry method.

また、放電極の本体部から突出するコロナ放電部から発生するコロナ放電によってコロナ電流とともにイオン風が集塵極側に向かって流れるが、放電極においてコロナ放電部が設けられていない反対側の集塵極との間ではコロナ放電が発生しないのでイオン風を利用することができない。また、コロナ放電部が設けられていない反対側では、コロナ電流や帯電ダストによる集塵空間での電荷量がコロナ放電部に比べて少ないため、集塵極近傍での電界強度の持ち上がりがコロナ放電部側に比べて小さく、クーロン力による集塵作用も弱くなる。このため、本発明者等は、コロナ放電部の反対側の集塵極の積極的な利用に着目した。 Further, the corona discharge generated from the corona discharge portion protruding from the main body of the discharge electrode causes the ion wind to flow toward the dust collection electrode side together with the corona current, but the collection on the opposite side where the corona discharge portion is not provided in the discharge electrode. Since no corona discharge is generated between the dust electrode and the dust electrode, ion wind cannot be used. In addition, on the opposite side where the corona discharge section is not provided, the amount of charge in the dust collection space due to the corona current and charged dust is smaller than that in the corona discharge section, so the increase in electric field strength near the dust collection electrode is corona discharge. It is smaller than the part side, and the dust collecting action due to the Coulomb force is also weakened. Therefore, the present inventors have focused on the active use of the dust collecting electrode on the opposite side of the corona discharge section.

本発明は、このような事情に鑑みてなされたものであって、コロナ放電部の反対側の集塵極であっても有効に集塵することができる電気集塵装置を提供することを目的とする。 The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electrostatic precipitator capable of effectively collecting dust even at a dust collecting electrode on the opposite side of a corona discharge unit. And.

本発明の一態様に係る電気集塵装置は、本体部と該本体部から突出するコロナ放電用のコロナ放電部とをそれぞれ有し、ガス流れ方向に沿って配列された複数の放電極と、前記ガス流れ方向に沿って配置され、前記コロナ放電部側に位置する放電側集塵極と、前記ガス流れ方向に沿って配置され、前記放電極を挟んで前記放電側集塵極の反対側に位置する反対側集塵極とを備え、複数の前記コロナ放電部は、前記ガス流れ方向に沿って配列され、前記ガス流れ方向に沿って隣り合う二つの前記コロナ放電部は、突出方向が同一の向きであり、前記コロナ放電部は、前記放電側集塵極にのみ向かって突出しており、前記放電極の前記本体部の中心は、前記放電側集塵極の中心を通る配列位置である第１中心軸線と前記反対側集塵極の中心を通る配列位置である第２中心軸線との間の中央位置よりも前記放電側集塵極から遠ざかる方向に位置されており、前記放電側集塵極は、前記ガス流れ方向に沿って間隔をあけて配置されており、前記反対側集塵極は、前記ガス流れ方向に沿って間隔をあけて配置されており、前記放電極において、前記コロナ放電部の先端から対向する前記放電側集塵極に向けてのみイオン風が発生する。 The electrostatic precipitator according to one aspect of the present invention has a main body portion and a corona discharge portion for corona discharge protruding from the main body portion, and has a plurality of emission electrodes arranged along the gas flow direction. The discharge side dust collecting electrode arranged along the gas flow direction and located on the corona discharge portion side and the opposite side of the discharge side dust collecting electrode across the discharge electrode and arranged along the gas flow direction. The plurality of corona discharge portions are arranged along the gas flow direction, and the two adjacent corona discharge portions along the gas flow direction have a protrusion direction. In the same orientation, the corona discharge portion protrudes only toward the discharge side dust collection electrode, and the center of the main body portion of the discharge electrode is at an arrangement position passing through the center of the discharge side dust collection electrode. It is located in a direction away from the discharge side dust collection electrode from the center position between a certain first central axis and the second central axis which is an arrangement position passing through the center of the opposite side dust collection electrode, and is located on the discharge side. The dust collecting electrodes are arranged at intervals along the gas flow direction, and the opposite side dust collecting electrodes are arranged at intervals along the gas flow direction . Ion wind is generated only from the tip of the corona discharge portion toward the discharge side dust collecting electrode facing the corona discharge portion .

本発明の一態様に係る電気集塵装置は、本体部と該本体部から突出するコロナ放電用のコロナ放電部とをそれぞれ有し、ガス流れ方向に沿って配列された複数の放電極と、前記ガス流れ方向に沿って配置され、前記コロナ放電部側に位置する放電側集塵極と、前記ガス流れ方向に沿って配置され、前記放電極を挟んで前記放電側集塵極の反対側に位置する反対側集塵極とを備え、複数の前記コロナ放電部は、前記ガス流れ方向に沿って配列され、前記ガス流れ方向に沿って隣り合う二つの前記コロナ放電部は、突出方向が同一の向きであり、前記コロナ放電部は、前記放電側集塵極にのみ向かって突出しており、前記放電極の前記本体部の中心は、前記放電側集塵極の中心を通る配列位置である第１中心軸線と前記反対側集塵極の中心を通る配列位置である第２中心軸線との間の中央位置よりも前記放電側集塵極から遠ざかる方向に位置されており、前記放電側集塵極及び前記反対側集塵極は、それぞれ開口が形成されており、前記放電極において、前記コロナ放電部の先端から対向する前記放電側集塵極に向けてのみイオン風が発生する。 The electrostatic precipitator according to one aspect of the present invention has a main body portion and a corona discharge portion for corona discharge protruding from the main body portion, and has a plurality of emission electrodes arranged along the gas flow direction. The discharge side dust collecting electrode arranged along the gas flow direction and located on the corona discharge portion side and the opposite side of the discharge side dust collecting electrode across the discharge electrode and arranged along the gas flow direction. The plurality of corona discharge portions are arranged along the gas flow direction, and the two adjacent corona discharge portions along the gas flow direction have a protrusion direction. In the same orientation, the corona discharge portion protrudes only toward the discharge side dust collection electrode, and the center of the main body portion of the discharge electrode is at an arrangement position passing through the center of the discharge side dust collection electrode. It is located in a direction away from the discharge side dust collection electrode from the center position between a certain first central axis and the second central axis which is an arrangement position passing through the center of the opposite side dust collection electrode, and is located on the discharge side. An opening is formed in each of the dust collecting electrode and the opposite side dust collecting electrode, and ion wind is generated only from the tip of the corona discharging portion toward the discharging side dust collecting electrode facing the dust collecting electrode .

放電極は、集塵極のうちの一方の放電側集塵極にのみ向かって突出するコロナ放電部を有している。これにより、コロナ放電部から放電側集塵極のみに向かってコロナ放電させてイオン風を流すことができる。この方式は、通常の放電極ではコロナ放電部を両側に有することで両サイドにイオン風を流す方式に比べ、集塵極を挟んで相対する放電極との間でのイオン風の干渉をなくすことができるメリットがある。
しかしながら放電極を挟んで放電側集塵極の反対側、すなわちコロナ放電部の反対側に位置する反対側集塵極は、コロナ放電部に対向していないのでコロナ放電はほとんど生じない。しかし、放電極の本体部の中心が放電側集塵極と反対側集塵極との間の中央位置よりも放電側集塵極から遠ざかる方向に位置されているので、放電極の本体部と反対側集塵極とが近づくことになる。これにより、放電極の本体部と反対側集塵極との間の電界強度を増加させることができ、反対側電極においてもクーロン力の向上による集塵効率を高めることができる。
放電極の本体部の中心は、例えば、放電側集塵極と反対側集塵極との間の距離が３００ｍｍ以上５００ｍｍ以下とされている場合、反対側集塵極側に１０ｍｍ以上離れて位置されていることが好ましい。
集塵極としては、例えば、複数の剛性を有する部材を所定間隔で並べた離散形集塵極が挙げられる。剛性を有する部材としては、例えば本体部がパイプ形状とされた部材が挙げられる。また、他の形式の集塵極としては、例えば、複数の貫通孔を有する板状体とされた平板集塵極が挙げられる。平板集塵極としては、例えばパンチングメタルや金網が用いられる。 The discharge electrode has a corona discharge portion that projects toward only one of the dust collection electrodes on the discharge side. As a result, the corona discharge can be performed from the corona discharge unit toward only the dust collecting electrode on the discharge side, and the ion air can flow. Compared to the method in which ion air flows on both sides by having corona discharge parts on both sides in a normal discharge electrode, this method eliminates the interference of ion wind between the discharge electrodes facing each other with the dust collecting electrode in between. There is a merit that can be done.
However, since the opposite side dust collecting electrode located on the opposite side of the discharge side dust collecting electrode across the discharge electrode, that is, the opposite side of the corona discharge portion does not face the corona discharge portion, corona discharge hardly occurs. However, since the center of the main body of the discharge electrode is located farther from the discharge side dust collection electrode than the central position between the discharge side dust collection electrode and the opposite side dust collection electrode, the main body of the discharge electrode The dust collecting electrode on the opposite side will come closer. As a result, the electric field strength between the main body of the discharge electrode and the dust collecting electrode on the opposite side can be increased, and the dust collection efficiency can be improved by improving the Coulomb force also on the opposite electrode.
The center of the main body of the discharge electrode is located, for example, 10 mm or more away from the opposite side dust collecting electrode when the distance between the discharging side dust collecting electrode and the opposite side dust collecting electrode is 300 mm or more and 500 mm or less. It is preferable that it is.
Examples of the dust collecting electrode include a discrete dust collecting electrode in which a plurality of rigid members are arranged at predetermined intervals. Examples of the rigid member include a member having a pipe-shaped main body. Further, as another type of dust collecting electrode, for example, a flat plate dust collecting electrode formed into a plate-like body having a plurality of through holes can be mentioned. As the flat plate dust collecting electrode, for example, punching metal or wire mesh is used.

さらに、本発明の一態様に係る電気集塵装置では、前記放電極の前記本体部の中心と前記放電側集塵極の前記第１中心軸線との間の距離をＤ１、前記放電極の前記本体部の中心と前記反対側集塵極の前記第２中心軸線との間の距離をＤ２とした場合、１．１ ≦ Ｄ１／Ｄ２ ≦ ２．０とされている。 Further, in the electrostatic precipitator according to one aspect of the present invention, the distance between the center of the main body of the discharge electrode and the first central axis of the discharge side dust collection electrode is D1, and the discharge electrode is said to have the same distance. When the distance between the center of the main body and the second central axis of the opposite side dust collecting electrode is D2, 1.1 ≤ D1 / D2 ≤ 2.0.

１．１ ≦ Ｄ１／Ｄ２ ≦ ２．０とすることにより、放電極の本体部と反対側集塵極との間の電界強度を増加させつつ、当該電界強度をコロナ放電部と放電側集塵極との間の電界強度に近づけることができる。１．１＞Ｄ１／Ｄ２とする場合と比べて、集塵性能が向上し、Ｄ１／Ｄ２＞２．０とする場合と異なり、火花放電の発生を防止できる。 By setting 1.1 ≤ D1 / D2 ≤ 2.0, the electric field strength between the main body of the discharge electrode and the dust collecting electrode on the opposite side is increased, and the electric field strength is increased between the corona discharge part and the dust collecting electrode on the discharge side. It can approach the electric field strength between the poles. Compared with the case of 1.1> D1 / D2, the dust collection performance is improved, and unlike the case of D1 / D2> 2.0, the generation of spark discharge can be prevented.

更に、本発明の一態様に係る電気集塵装置では、複数の前記放電側集塵極と複数の前記反対側集塵極は、それぞれ前記ガス流れ方向に沿って配列され、前記Ｄ１は、前記放電極の本体部の中心と前記放電側集塵極の前記第１中心軸線との間の距離であり、前記Ｄ２は、前記放電極の本体部の中心と前記反対側集塵極の前記第２中心軸線との間の距離である。 Further, in the electrostatic precipitator according to one aspect of the present invention, the plurality of the discharge side dust collecting electrodes and the plurality of the opposite side dust collecting electrodes are arranged along the gas flow direction, respectively, and the D1 is the said. The distance between the center of the main body of the discharge electrode and the first central axis of the discharge side dust collecting electrode, where D2 is the center of the main body of the discharge electrode and the first of the opposite side dust collecting electrode. 2 The distance between the central axis and the center axis.

放電側集塵極と反対側集塵極がそれぞれ一方向に沿って配列されており、Ｄ１は、放電側集塵極の配列方向に対して垂直方向において放電極の本体部の中心と放電側集塵極の配列位置との間の距離であり、Ｄ２は、反対側集塵極の配列方向に対して垂直方向において放電極の本体部の中心と反対側集塵極の配列位置との間の距離である。 The discharge side dust collection electrode and the opposite side dust collection electrode are arranged along one direction, respectively, and D1 is the center of the main body of the discharge electrode and the discharge side in the direction perpendicular to the arrangement direction of the discharge side dust collection electrode. It is the distance between the arrangement position of the dust collecting electrode, and D2 is between the center of the main body of the discharge electrode and the arrangement position of the opposite side dust collecting electrode in the direction perpendicular to the arrangement direction of the opposite side dust collecting electrode. Distance.

さらに、本発明の一態様に係る電気集塵装置では、前記放電極と前記放電側集塵極との間の電界強度と、前記放電極と前記反対側集塵極との間の電界強度とが同等とされている。 Further, in the electrostatic precipitator according to one aspect of the present invention, the electric field strength between the discharge electrode and the discharge side dust collection electrode and the electric field strength between the discharge electrode and the opposite side dust collection electrode Is equivalent.

放電極と放電側集塵極との間の電界強度と、放電極と反対側集塵極との間の電界強度とが同等とすることで、放電極の本体部の中心を両集塵極間の中央に位置させる場合に比べて、放電極と反対側電極との間の電界強度を増加させることができる。 By making the electric field strength between the discharge electrode and the dust collecting electrode on the discharge side equal to the electric field strength between the discharge electrode and the dust collecting electrode on the opposite side, the center of the main body of the discharge electrode is centered on both dust collecting electrodes. The electric field strength between the discharge electrode and the opposite electrode can be increased as compared with the case where it is located in the center of the space.

さらに、本発明の一態様に係る電気集塵装置では、前記コロナ放電部の先端は、前記放電側集塵極の前記第１中心軸線と前記反対側集塵極の前記第２中心軸線との間の前記中央位置よりも前記反対側集塵極側に位置している。 Further, in the electrostatic precipitator according to one aspect of the present invention, the tip of the corona discharge portion has the first central axis of the discharge side dust collecting electrode and the second central axis of the opposite side dust collecting electrode. It is located on the opposite side of the dust collecting electrode side from the central position between the two.

コロナ放電部の先端を、両集塵極間の中央位置よりも反対側集塵極側に位置させることで、コロナ放電部と放電側集塵極との間の電界強度を低下させつつも、放電極の本体部との反対側電極との間の電界強度を増加させることができる。 By locating the tip of the corona discharge section on the opposite side of the dust collection electrode side from the central position between the two dust collection electrodes, the electric field strength between the corona discharge section and the discharge side dust collection electrode is reduced, while The electric field strength between the main body of the release electrode and the opposite electrode can be increased.

放電極の本体部と反対側集塵極との間の電界強度を増加させることで、反対側電極においてもクーロン力の向上により集塵効率を高めることができ、反対側集塵極であってもさらに有効に集塵することができる。 By increasing the electric field strength between the main body of the discharge electrode and the dust collecting electrode on the opposite side, the dust collection efficiency can be improved by improving the Coulomb force even on the opposite electrode, and the dust collecting electrode on the opposite side. Can also collect dust more effectively.

本発明の一実施形態に係る電気集塵装置を示した斜視図である。It is a perspective view which showed the electrostatic precipitator which concerns on one Embodiment of this invention. 図１の電気集塵装置を上方から見た平面図である。FIG. 5 is a plan view of the electrostatic precipitator of FIG. 1 as viewed from above. 図１の電気集塵装置をガス流れ方向から見た正面図である。It is a front view which looked at the electrostatic precipitator of FIG. 1 from the gas flow direction. 集塵極と放電極との位置関係を示した平面図である。It is a top view which showed the positional relationship between a dust collecting electrode and a discharge electrode. 放電極の突起部に相当する高さ位置の横断面図である。It is a cross-sectional view of the height position corresponding to the protrusion of the release electrode. オフセット無し場合の放電側放電極と集塵極間の電界強度を示した図である。It is a figure which showed the electric field strength between a discharge side discharge electrode and a dust collecting electrode when there is no offset. オフセット無し場合の反対側放電極と集塵極間の電界強度を示した図である。It is the figure which showed the electric field strength between the opposite side discharge electrode and a dust collecting electrode when there is no offset. オフセット有り場合の放電側放電極と集塵極間の電界強度を示した図である。It is a figure which showed the electric field strength between a discharge side discharge electrode and a dust collecting electrode when there is an offset. オフセット有り場合の反対側放電極と集塵極間の電界強度を示した図である。It is the figure which showed the electric field strength between the opposite side discharge electrode and a dust collecting electrode with an offset. 放電極の変形例を示した正面図である。It is a front view which showed the modification of the release electrode. 放電極の他の変形例を示した正面図である。It is a front view which showed the other modification of the release electrode. 集塵極の変形例を示した平面図である。It is a top view which showed the modification of the dust collecting electrode. 集塵極の変形例を示した正面図である。It is a front view which showed the modification of the dust collecting electrode. 集塵極の他の変形例を示した平面図である。It is a top view which showed the other modification of the dust collecting electrode. 集塵極の他の変形例を示した正面図である。It is a front view which showed the other modification of the dust collecting electrode. 集塵性能指数比とオフセット比の関係を示すグラフである。It is a graph which shows the relationship between the dust collection performance index ratio and the offset ratio. 集塵極近傍の電界強度とオフセット比の関係を示すグラフである。It is a graph which shows the relationship between the electric field strength and the offset ratio in the vicinity of a dust collecting electrode. 本発明の一実施形態に係る電気集塵装置を示した平面図である。It is a top view which showed the electrostatic precipitator which concerns on one Embodiment of this invention.

以下に、本発明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 the electrostatic precipitator according to the present invention 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。また、電気集塵装置１は、火力発電プラント用とは各構成要素のサイズが異なるが、建築物や地下空間等に設置され、微小粒子状物質（例えばＰＭ２．５など）を回収し、空間内の空気を浄化する。 The electrostatic precipitator 1 is used in, for example, a thermal power plant using coal or the like as fuel, and recovers dust (particulate matter) in combustion exhaust gas derived from a boiler. Further, although the size of each component of the electrostatic precipitator 1 is different from that for a thermal power plant, it is installed in a building, an underground space, etc., and collects fine particulate matter (for example, PM2.5) to create a space. Purify the air inside.

電気集塵装置１は、例えば金属製等の導電性とされた複数の集塵極４を備えている。集塵極４は、円形の横断面を有する中空の柱状とされた円形パイプとされており、長手方向であるｚ方向に直交するｘ方向（ガス流れＧ方向）に所定の間隔をあけて配列されている。ｘ方向に配列された集塵極４の列は、ｚ方向及びｘ方向に直交するｙ方向に所定間隔をあけて平行に複数列設けられている。集塵極４の各列の間に、ｘ−ｚ面内に放電極５が配置されている。図１では、放電極５の取付枠５ｃの位置が示されている。放電極５は、図１から分かるように、ガス流れＧ方向に直交するｙ方向に並ぶ集塵極４間の中央位置ＣＬから一方の集塵極４側（図１ではｙ方向の右側）にオフセットされている。 The electrostatic precipitator 1 includes a plurality of conductive dust collecting electrodes 4 such as those made of metal. The dust collecting poles 4 are hollow columnar circular pipes having a circular cross section, and are arranged at predetermined intervals in the x direction (gas flow G direction) orthogonal to the z direction which is the longitudinal direction. Has been done. A plurality of rows of dust collecting poles 4 arranged in the x direction are provided in parallel at predetermined intervals in the z direction and the y direction orthogonal to the x direction. A emission electrode 5 is arranged in the x-z plane between each row of the dust collecting electrodes 4. In FIG. 1, the position of the mounting frame 5c of the discharge electrode 5 is shown. As can be seen from FIG. 1, the discharge electrode 5 is located on one dust collecting electrode 4 side (on the right side in the y direction in FIG. 1) from the central position CL between the dust collecting electrodes 4 arranged in the y direction orthogonal to the gas flow G direction. It is offset.

集塵極４は接地されている。放電極５は、図示しない負の極性を有する電源に接続されている。なお、放電極５に接続する電源は正の極性を有していても良い。 The dust collecting electrode 4 is grounded. The release electrode 5 is connected to a power supply having a negative polarity (not shown). The power supply connected to the discharge electrode 5 may have a positive polarity.

図２に示すように、放電極５は、取付枠５ｃに固定された本体部５ｂと、本体部５ｂから突出するトゲ状とされた複数の突起部（コロナ放電部）５ａとを備えている。突起部５ａは、一方の集塵極４側のみに先端を向けて突出するように設けられている。突起部５ａは、ガス流れＧ方向であるｘ方向において、集塵極４の間に位置するように配置されている。突起部５ａにおいてコロナ放電が発生し、突起部５ａの先端から対向する集塵極４側に向けてイオン風が発生する。 As shown in FIG. 2, the discharge electrode 5 includes a main body portion 5b fixed to the mounting frame 5c, and a plurality of thorn-shaped protrusions (corona discharge portions) 5a protruding from the main body portion 5b. .. The protrusion 5a is provided so as to project so that the tip thereof is directed only to one dust collecting electrode 4 side. The protrusions 5a are arranged so as to be located between the dust collecting poles 4 in the x direction, which is the gas flow G direction. A corona discharge is generated at the protrusion 5a, and an ionic wind is generated from the tip of the protrusion 5a toward the facing dust collecting electrode 4.

図２に示されているように、放電極５の本体部５ｂの中心Ｃ１は、集塵極４間の中央位置ＣＬからオフセットされている。具体的には、放電極５の本体部５ｂの中心Ｃ１は、突起部５ａが対向する集塵極４（以下、この集塵極４を「放電側集塵極４ａ」という。）から遠ざかる方向に、かつ、突起部５ａの反対側の集塵極４（以下、この集塵極４を「反対側集塵極４ｂ」という。）に近づくように中央位置ＣＬから位置がずらされている。したがって、本体部５ｂの中心Ｃ１と放電側集塵極４ａの中心Ｃ２を通る配列位置との間のｙ方向に見た距離Ｄ１は、本体部５ｂの中心Ｃ１と反対側集塵極４ｂの中心Ｃ３を通る配列位置との間のｙ方向に見た距離Ｄ２よりも大きい（Ｄ１＞Ｄ２）。なお、放電極５と集塵極４とがｙ方向に交互に配置されているので、１つの集塵極４のうち、突起部５ａ側が放電側集塵極４ａとなり、突起部５ａの反対側が反対側集塵極４ｂとなる。 As shown in FIG. 2, the center C1 of the main body 5b of the discharge electrode 5 is offset from the central position CL between the dust collecting electrodes 4. Specifically, the center C1 of the main body portion 5b of the discharge electrode 5 is in a direction away from the dust collecting electrode 4 (hereinafter, the dust collecting electrode 4 is referred to as “discharge side dust collecting electrode 4a”) with which the protrusion 5a faces. In addition, the position is shifted from the central position CL so as to approach the dust collecting electrode 4 on the opposite side of the protrusion 5a (hereinafter, the dust collecting electrode 4 is referred to as "opposite side dust collecting electrode 4b"). Therefore, the distance D1 seen in the y direction between the center C1 of the main body 5b and the arrangement position passing through the center C2 of the discharge side dust collecting pole 4a is the center of the dust collecting pole 4b opposite to the center C1 of the main body 5b. It is larger than the distance D2 seen in the y direction from the array position passing through C3 (D1> D2). Since the discharge electrodes 5 and the dust collecting poles 4 are alternately arranged in the y direction, the protrusion 5a side of one dust collecting pole 4 becomes the discharge side dust collecting pole 4a, and the opposite side of the protrusion 5a is. It becomes the opposite side dust collecting electrode 4b.

距離Ｄ１は、放電極５の本体部５ｂの中心Ｃ１と放電側集塵極４ａの中心Ｃ２を通る配列位置との間の距離である。すなわち、Ｄ１は、放電側集塵極４ａの配列方向に対して垂直方向（ｙ方向）において放電極５の本体部５ｂの中心Ｃ１と放電側集塵極４ａの配列位置（中心軸線）との間の距離である。 The distance D1 is the distance between the center C1 of the main body 5b of the discharge electrode 5 and the arrangement position passing through the center C2 of the discharge side dust collecting electrode 4a. That is, D1 is the center C1 of the main body 5b of the discharge electrode 5 and the arrangement position (center axis) of the discharge side dust collection electrode 4a in the direction (y direction) perpendicular to the arrangement direction of the discharge side dust collection electrode 4a. The distance between them.

距離Ｄ２は、放電極５の本体部５ｂの中心Ｃ１と反対側集塵極４ｂの中心Ｃ３を通る配列位置との間の距離である。すなわち、Ｄ２は、反対側集塵極４ｂの配列方向に対して垂直方向（ｙ方向）において放電極５の本体部５ｂの中心Ｃ１と反対側集塵極４ｂの配列位置（中心軸線）との間の距離である。 The distance D2 is the distance between the center C1 of the main body 5b of the discharge electrode 5 and the arrangement position passing through the center C3 of the opposite side dust collecting electrode 4b. That is, D2 is the center C1 of the main body 5b of the discharge electrode 5 and the arrangement position (center axis) of the opposite side dust collecting electrode 4b in the direction (y direction) perpendicular to the arrangement direction of the opposite side dust collecting electrode 4b. The distance between them.

突起部５ａの先端は、例えば放電極５の本体部５ｂの中心から放電部先端までの距離、すなわちＤｄ／２＋Ｌｂ（図４Ｂ参照）が３０ｍｍ未満、好ましくは２０ｍｍ程度とされた場合には、中央位置ＣＬよりも反対側集塵極４ｂ側に位置するように配置されている。 The tip of the protrusion 5a is, for example, the center when the distance from the center of the main body 5b of the release electrode 5 to the tip of the discharge portion, that is, Dd / 2 + Lb (see FIG. 4B) is less than 30 mm, preferably about 20 mm. It is arranged so as to be located on the dust collecting electrode 4b side opposite to the position CL.

上記のように、突起部５ａを一方向に向け、かつｘ方向において集塵極４の間に配置することで、突起部５ａから放電側集塵極４ａに向かうイオン風が略同じ方向を向かい、イオン風の干渉を避けることができるようになっている。 As described above, by directing the protrusion 5a in one direction and arranging it between the dust collecting poles 4 in the x direction, the ion wind from the protrusion 5a toward the discharge side dust collecting pole 4a faces substantially the same direction. , Ion wind interference can be avoided.

図３には、図１をガス流れＧ方向から見た正面図が示されている。同図に示されているように、突起部５ａは、高さ方向において、所定間隔を空けて設けられている。 FIG. 3 shows a front view of FIG. 1 as viewed from the gas flow G direction. As shown in the figure, the protrusions 5a are provided at predetermined intervals in the height direction.

図４Ａには、集塵極４と放電極５とを平面視したときの位置関係が示されている。
ガス流れＧ方向であるｘ方向に並ぶ集塵極４の間隔はＰｃ、ｘ方向に並ぶ放電極５の間隔はＰｄとされる。また、ｙ方向に並ぶ集塵極４の間隔は２Ｄとされる。集塵極４の直径はＤｃとされる。 FIG. 4A shows the positional relationship between the dust collecting electrode 4 and the discharging electrode 5 in a plan view.
The distance between the dust collecting electrodes 4 arranged in the x direction, which is the gas flow G direction, is Pc, and the distance between the discharge electrodes 5 arranged in the x direction is Pd. Further, the distance between the dust collecting poles 4 arranged in the y direction is 2D. The diameter of the dust collecting electrode 4 is Dc.

本実施形態において、放電極５のオフセット位置、すなわち、放電極５の本体部５ｂの中心が中央位置ＣＬからｙ方向にずれる位置は、距離Ｄ１及び距離Ｄ２の比が、１．１ ≦ Ｄ１／Ｄ２ ≦ ２．０の範囲に設定されることが望ましい。Ｄ１／Ｄ２の下限は、１．２とされると更によい。 In the present embodiment, at the offset position of the release electrode 5, that is, the position where the center of the main body 5b of the release electrode 5 deviates from the center position CL in the y direction, the ratio of the distance D1 and the distance D2 is 1.1 ≤ D1 /. It is desirable to set it in the range of D2 ≤ 2.0. The lower limit of D1 / D2 is even better set to 1.2.

放電極５の突起部５ａの先端と最も近い放電側集塵極４ａの側面との距離はＬ１、放電極５の突起部５ａの反対側の本体部５ｂと最も近い反対側集塵極４ｂの側面との距離はＬ２とされる。
なお、図４Ａにおいて示される放電極５と集塵極４との間に描かれた曲線は電気力線である。 The distance between the tip of the protrusion 5a of the discharge electrode 5 and the side surface of the closest discharge side dust collection electrode 4a is L1, and the distance between the main body 5b on the opposite side of the protrusion 5a of the discharge electrode 5 and the closest opposite side dust collection electrode 4b The distance from the side surface is L2.
The curve drawn between the discharge electrode 5 and the dust collecting electrode 4 shown in FIG. 4A is an electric line of force.

図４Ｂには、放電極５の突起部５ａに相当する高さ位置における横断面が拡大して示されている。同図に示すように、放電極５の本体部５ｂは円形断面を有しており、その直径はＤｄとされる。突起部５ａが本体部５ｂから突出する突起長さはＬｂとされる。 FIG. 4B shows an enlarged cross section at a height position corresponding to the protrusion 5a of the release electrode 5. As shown in the figure, the main body 5b of the release electrode 5 has a circular cross section, and its diameter is Dd. The length of the protrusion 5a protruding from the main body 5b is Lb.

図４Ａ及び図４Ｂに示した諸元を用いると、Ｌ１及びＬ２は下式のように表すことができる。
Ｌ１＝（（Ｄ１−Ｄｄ／２−Ｌｂ）^２＋（Ｐｄ／２）^２）^０．５−Ｄｃ／２
Ｌ２＝（Ｄ２^２＋（Ｐｄ／２）^２）^０．５−Ｄｃ／２−Ｄｄ／２
そして、放電極５の本体部５ｂの中心が中央位置ＣＬからｙ方向にずれるオフセット量Ｌｅは、下式によって表される。
Ｌｅ＝（Ｄ１−Ｄ２）／２
なお、図４Ａ及び図４Ｂでは、トゲ状の突起部５ａの位置での断面での例を示したが、実際には突起部５ａが占める部分は放電極５の一部であり、隣り合う二つの突起部５ａ間の部分が放電極５の大部分を占める。そのため、突起部５ａの長さＬｂは無視してＬ１、Ｌ２を評価しても構わない。 Using the specifications shown in FIGS. 4A and 4B, L1 and L2 can be expressed as the following equations.
L1 = ((D1-Dd / 2-Lb) ² + (Pd / 2) ² ) ^0.5- Dc / 2
L2 = (D2 ² + (Pd / 2) ² ) ^0.5- Dc / 2-Dd / 2
The offset amount Le at which the center of the main body 5b of the release electrode 5 deviates from the center position CL in the y direction is expressed by the following equation.
Le = (D1-D2) / 2
In addition, in FIG. 4A and FIG. The portion between the two protrusions 5a occupies most of the release electrode 5. Therefore, the length Lb of the protrusion 5a may be ignored and L1 and L2 may be evaluated.

ｙ方向に並ぶ集塵極４間の距離である２Ｄは、たとえば一般産業用では３００ｍｍ以上５００ｍｍ以下とされている。ただし他の用途では、それ以外の寸法とすることもできる。 The 2D, which is the distance between the dust collecting electrodes 4 arranged in the y direction, is set to 300 mm or more and 500 mm or less for general industrial use, for example. However, for other uses, other dimensions may be used.

次に、図５Ａ乃至図６Ｂを用いて、放電極５をオフセットさせた場合の作用効果について説明する。 Next, the action and effect when the release electrode 5 is offset will be described with reference to FIGS. 5A to 6B.

図５Ａ及び図５Ｂには、オフセット量Ｌｅ＝０とされたオフセット無しの場合、すなわち放電極５の本体部５ｂが中央位置ＣＬ上に設けられている場合の電界強度分布が示されている。図５Ａに示すように、突起部５ａと放電側集塵極４ａとの間は、コロナ電流が流れるにしたがい、放電側集塵極４ａ近傍の電界強度E1maxは空間中に存在するマイナスイオンと帯電ダストが有する空間電荷で上昇する。この放電側集塵極４ａ付近での火花放電限界の電界強度（Ecr）が最大の印加可能な最大電界強度の条件となる（E1max≦Ecr）。 5A and 5B show the electric field strength distribution when there is no offset when the offset amount Le = 0, that is, when the main body portion 5b of the emission electrode 5 is provided on the central position CL. As shown in FIG. 5A, as the corona current flows between the protrusion 5a and the discharge side dust collection electrode 4a, the electric field strength E1max near the discharge side dust collection electrode 4a is charged with negative ions existing in the space. It rises due to the space charge of the dust. The electric field strength (Ecr) at the spark discharge limit near the discharge-side dust collecting electrode 4a is the condition for the maximum applicable maximum electric field strength (E1max ≦ Ecr).

一方、図５Ｂに示すように、突起部５ａの反対側と反対側集塵極４ｂとの間では、図５Ａのような空間電荷による持ち上がりがないため、反対側集塵極４ｂ近傍の電界強度E2maxは、E１maxよりも小さい。
なお、電界強度を距離Ｌ１，Ｌ２で積分した面積Ａ１，Ａ２はそれぞれが印加電圧Voに相当するため、等しい値となる。 On the other hand, as shown in FIG. 5B, since there is no lifting due to space charge as in FIG. 5A between the opposite side of the protrusion 5a and the opposite side dust collecting electrode 4b, the electric field strength in the vicinity of the opposite side dust collecting electrode 4b E2max is smaller than E1max.
The areas A1 and A2 obtained by integrating the electric field strengths at the distances L1 and L2 correspond to the applied voltage Vo, and therefore have equal values.

図６Ａ及び図６Ｂには、本実施形態に相当し、放電極５が中央位置ＣＬからオフセットされた場合の放電極５と集塵極４との間の電界強度分布が示されている。図６Ａが図５Ａに対応し、図６Ｂが図５Ｂに対応する。 6A and 6B show the electric field strength distribution between the discharge electrode 5 and the dust collecting electrode 4 when the discharge electrode 5 is offset from the central position CL, which corresponds to the present embodiment. FIG. 6A corresponds to FIG. 5A and FIG. 6B corresponds to FIG. 5B.

図６Ａ及び６Ｂに示されているように、突起部５ａと放電側集塵極４ａとの間の電界強度は、オフセットによりＬ１＞Ｌ２又はＤ１＞Ｄ２とされているため、放電側集塵極４ａ近傍の電界強度E1maxは、オフセット無しの場合と同じ電圧Voであれば、図５Ａよりは低下し、E1ave.（＝Vo/L1）も小さくなる。一方、オフセットによって図５Ｂの場合よりもＬ２が小さくなり、平均電界強度E2ave.が大きくなることで、反対側集塵極４ｂ近傍の電界強度E2maxは増加させることができる。 As shown in FIGS. 6A and 6B, the electric field strength between the protrusion 5a and the discharge side dust collecting electrode 4a is L1> L2 or D1> D2 due to the offset, so that the discharge side dust collecting electrode If the electric field strength E1max in the vicinity of 4a is the same voltage Vo as in the case without offset, it is lower than that in FIG. 5A, and E1ave. (= Vo / L1) is also smaller. On the other hand, due to the offset, L2 becomes smaller than in the case of FIG. 5B and the average electric field strength E2ave. Becomes larger, so that the electric field strength E2max in the vicinity of the opposite side dust collecting electrode 4b can be increased.

一般に、E1maxが火花放電限界電界強度Ecr以下での運転となるが、オフセットすることで突起物側の距離が長くなるため、オフセット無しの場合に比べて当初のE1maxと同じ電界強度にするためには、印加線圧Vnそのものを高くすることができ（Vn>Vo）、このため突起物と反対側の最大電界強度E2maxもさらに高くすることができる。このように、オフセットするとともに、印加電圧を高くすることで、電界強度E1maxをオフセット前と同等に維持しつつ、E2maxをE1maxと同じレベルまで高くすることで、集塵極近傍の最も集塵に効果のある場の電界強度を高め、クーロン力による捕集効率を高めることが可能となる。なお、オフセットすることでコロナ放電側の距離は大きくなり、この間を移動するダストの移動距離は大きくなるが、この部分でのダストの移動はイオン風が主体となるため、若干の到達距離の増加や途中の平均電界強度の低下は性能にはマイナスとならず、放電側集塵極４ａの裏側の反対側集塵極４ｂに回り込んだダストの反対側集塵極４ｂ近傍の電界強度E2max の増大で性能を高くすることが可能となる。 Generally, E1max is operated at the spark discharge limit electric field strength Ecr or less, but since the distance on the protrusion side becomes longer due to the offset, in order to make the electric field strength the same as the initial E1max compared to the case without offset. Can increase the applied linear pressure Vn itself (Vn> Vo), so that the maximum electric field strength E2max on the opposite side of the protrusion can also be increased. In this way, by offsetting and increasing the applied voltage, the electric field strength E1max is maintained at the same level as before the offset, and by increasing E2max to the same level as E1max, the most dust collection near the dust collection electrode is achieved. It is possible to increase the electric field strength of the effective field and increase the collection efficiency by the Coulomb force. By offsetting, the distance on the corona discharge side becomes larger, and the moving distance of the dust moving between them becomes larger, but the movement of dust in this part is mainly due to the ion wind, so the reachable distance increases slightly. The decrease in the average electric field strength on the way does not have a negative effect on the performance, and the electric field strength E2max near the dust collecting electrode 4b on the opposite side of the dust wrapping around the dust collecting electrode 4b on the opposite side of the discharging side dust collecting electrode 4a It becomes possible to improve the performance by increasing.

オフセット量Ｌｅは、放電側集塵極４ａの電界強度E1maxと反対側集塵極４ｂの電界強度E2maxとが同等となるように調整されることが好ましい。図５Ａ乃至図６Ｂで示す電界強度の例は、パイプ状の集塵極４を間隔をあけて配置した事例であり、Ｌ１，Ｌ２での最短距離をベースに記載している。集塵極４の電極例としては、メッシュ状の電極等もあるため、以下はオフセット量を定義するため、集塵極４の中心Ｃ２，Ｃ３を通過する配列位置と放電極５の中心Ｃ１間距離であるＤ１，Ｄ２でまとめて表記する。この場合、パイプ状の電極であっても、Ｌ１，Ｌ２でなく、Ｄ１，Ｄ２で評価しても実用上の範囲ではほぼ同等とみなせるため、支障はない。 The offset amount Le is preferably adjusted so that the electric field strength E1max of the discharge side dust collecting electrode 4a and the electric field strength E2max of the opposite side dust collecting electrode 4b are equal to each other. The examples of the electric field strength shown in FIGS. 5A to 6B are examples in which the pipe-shaped dust collecting electrodes 4 are arranged at intervals, and are described based on the shortest distances in L1 and L2. As an example of the electrode of the dust collecting electrode 4, there is a mesh-shaped electrode or the like. Therefore, in order to define the offset amount below, the arrangement position passing through the centers C2 and C3 of the dust collecting electrode 4 and the center C1 of the discharging electrode 5 are provided. The distances D1 and D2 are collectively indicated. In this case, even if the electrodes are pipe-shaped, even if they are evaluated by D1 and D2 instead of L1 and L2, they can be regarded as substantially the same in a practical range, so that there is no problem.

両者の電界強度が等しくなる範囲は、例えば、１．５ ≦ Ｄ１／Ｄ２ ≦ １．８である。但し、電気集塵装置１の運転条件や集塵極４又は放電極５の条件によって最適なＤ１／Ｄ２の範囲は変動する。 The range in which the electric field strengths of the two are equal is, for example, 1.5 ≤ D1 / D2 ≤ 1.8. However, the optimum range of D1 / D2 varies depending on the operating conditions of the electrostatic precipitator 1 and the conditions of the dust collecting electrode 4 or the discharging electrode 5.

距離Ｄ１及び距離Ｄ２の比Ｄ１／Ｄ２の下限は、例えば１．１であり、より望ましくは１．２である。図１０に示すように、ガス流れＧの流速によって、オフセット量と集塵性能の関係が変化するという知見が得られている。ガス流れＧが比較的速いときは、Ｄ１／Ｄ２が１．１以上になると、集塵性能が向上する。ガス流れＧが比較的遅いときは、Ｄ１／Ｄ２が１．２以上になると、集塵性能が向上し、この範囲では、ガス流れＧが比較的速いときは、集塵性能が確実に向上する。 The lower limit of the ratio D1 / D2 of the distance D1 and the distance D2 is, for example, 1.1, more preferably 1.2. As shown in FIG. 10, it has been found that the relationship between the offset amount and the dust collection performance changes depending on the flow velocity of the gas flow G. When the gas flow G is relatively fast, the dust collection performance is improved when D1 / D2 is 1.1 or more. When the gas flow G is relatively slow, the dust collection performance is improved when D1 / D2 is 1.2 or more, and in this range, when the gas flow G is relatively fast, the dust collection performance is surely improved. ..

ガス流れＧの流速が速い条件では、よりクーロン力の影響が大きいため、電界強度の増大に影響を受けて、比較的小さいオフセット量（例えば１．１ ≦ Ｄ１／Ｄ２）でも集塵性能が向上する。これに対し、流速が遅い条件では、イオン風の影響が大きいことから、電界強度の増大によって集塵性能が向上するには、より大きなオフセット量（例えば１．２ ≦ Ｄ１／Ｄ２）が必要になる。１．２ ≦ Ｄ１／Ｄ２であれば、ガス流れＧの流速に関わらず、集塵性能を向上させることができる。 Under the condition that the flow velocity of the gas flow G is high, the influence of the Coulomb force is larger, so that the dust collection performance is improved even with a relatively small offset amount (for example, 1.1 ≤ D1 / D2) due to the influence of the increase in the electric field strength. do. On the other hand, under the condition that the flow velocity is slow, the influence of the ionic wind is large, so a larger offset amount (for example, 1.2 ≤ D1 / D2) is required to improve the dust collection performance by increasing the electric field strength. Become. If 1.2 ≤ D1 / D2, the dust collection performance can be improved regardless of the flow velocity of the gas flow G.

オフセット量を過大にすると、反対側集塵極近傍の電界強度E2max>E1maxとなり、コロナ放電部と反対側での火花放電限界電界強度が運転上の制約条件となり、コロナ放電側での性能が発揮できなくなるため、好ましくない。よって、最大のオフセット量はE2maxがE1maxを大きく超えない範囲に設定されることが望ましい。 If the offset amount is excessive, the electric field strength near the dust collecting electrode on the opposite side becomes E2max> E1max, and the spark discharge limit electric field strength on the opposite side of the corona discharge part becomes an operational constraint, and the performance on the corona discharge side is demonstrated. It is not preferable because it cannot be done. Therefore, it is desirable that the maximum offset amount is set within the range where E2max does not greatly exceed E1max.

図１１には、一般産業用の電気集塵装置１において、Ｄ１／Ｄ２を変化させた時のコロナ放電側（放電極５の本体部５ｂに突起部５ａを有する側、すなわち、放電線にトゲのある側）の放電側集塵極４ａ近傍の電界強度と、電界側（放電極５の本体部５ｂに突起部５ａを有さない側、すなわち、トゲのない側）の反対側集塵極４ｂ近傍の電界強度を解析して比較した例を示す。電気集塵装置１の運転条件としての電流電圧をともに上昇させていった。図１１において、左のグラフから右のグラフに行くに従い、電流電圧が高くなっている。 In FIG. 11, in the general industrial electrostatic precipitator 1, the corona discharge side when D1 / D2 is changed (the side having the protrusion 5a on the main body 5b of the discharge electrode 5, that is, the discharge line is splintered). The dust collection electrode on the opposite side of the electric field strength near the discharge side dust collection electrode 4a (the side with the discharge electrode 5) and the electric field side (the side where the main body 5b of the discharge electrode 5 does not have the protrusion 5a, that is, the side without the thorns). An example of analyzing and comparing the electric field strength in the vicinity of 4b is shown. Both the current and voltage as the operating conditions of the electrostatic precipitator 1 were increased. In FIG. 11, the current and voltage increase from the graph on the left to the graph on the right.

いずれの場合も、Ｄ１／Ｄ２＝１の場合には、トゲのある側の放電側集塵極４ａのほうがトゲの長さ分距離が近いことに加え、コロナ電流による空間電荷で電界が持ち上がる効果が加算されるため、トゲのある側の放電側集塵極４ａのほうの電界強度が高い。そして、電流が増えていくに従い、その持ち上がりの効果が大きくなり、電界強度の値が高くなっていく。 In either case, when D1 / D2 = 1, the discharge-side dust collecting electrode 4a on the side with the thorns is closer by the length of the thorns, and the electric field is lifted by the space charge due to the corona current. Is added, so that the electric field strength of the discharge side dust collecting electrode 4a on the side with the thorns is higher. Then, as the current increases, the effect of lifting the current increases, and the value of the electric field strength increases.

一方、図１１のいずれのグラフの場合もＤ１／Ｄ２が増えていくに従いトゲのない側の反対側集塵極４ｂの電界強度は一義的に増加していく傾向を示す。理想的にはトゲのある側とトゲのない側の電界強度が一致するポイントが、最もバランスの取れた電界強度配分と考えられる。しかし、実際の運転では、いろいろな条件が複合しているため、最適な条件は変動する。このため、図１０のＤ１／Ｄ２を変化させた時の集塵性の向上に関するテスト結果でも、集塵性能の最適ポイントもある程度のばらつきを有している。 On the other hand, in any of the graphs of FIG. 11, as D1 / D2 increases, the electric field strength of the dust collecting electrode 4b on the opposite side on the side without thorns tends to increase uniquely. Ideally, the point where the electric field strengths on the thorny side and the non-thorny side match is considered to be the most balanced electric field strength distribution. However, in actual operation, various conditions are compounded, so the optimum conditions fluctuate. Therefore, even in the test results regarding the improvement of the dust collection property when D1 / D2 in FIG. 10 is changed, the optimum point of the dust collection performance also has some variation.

また、図１１の右側のほうのグラフ、すなわち電流電圧を上昇させた運転では、特にオフセット量の大きなＤ１／Ｄ２が大きな領域では、一般産業用の電気集塵装置１での火花放電電界強度（これは、ガスの組成や運転温度条件によっても大きく異なるが、通常８ｋＶ／ｃｍ〜１２ｋＶ／ｃｍとされている。）をトゲのない側の反対側集塵極４ｂのほうが先に超えてしまうため、好ましくない。
より具体的には、Ｄ１／Ｄ２ ≦ ２．０とされることが望ましい。 Further, in the graph on the right side of FIG. 11, that is, in the operation in which the current voltage is increased, the spark discharge electric field strength in the general industrial electrostatic precipitator 1 is particularly large in the region where the offset amount is large and D1 / D2 is large. This varies greatly depending on the gas composition and operating temperature conditions, but it is usually 8 kV / cm to 12 kV / cm) because the dust collecting electrode 4b on the opposite side without thorns exceeds it first. , Not preferable.
More specifically, it is desirable that D1 / D2 ≤ 2.0.

Ｄ１／Ｄ２が２．０を超えると、反対側集塵極４ｂ側の電界強度が、電気集塵装置１の通常運転条件下において、火花放電が発生する領域に到達する、又は、到達する値に近くなる。そのため、電気集塵装置１の運転条件の制約を受けて、安定運転は困難になる。したがって、Ｄ１／Ｄ２の上限は２．０とされることが望ましい。 When D1 / D2 exceeds 2.0, the electric field strength on the opposite side dust collecting electrode 4b side reaches or reaches the region where spark discharge occurs under the normal operating conditions of the electrostatic precipitator 1. Become closer to. Therefore, stable operation becomes difficult due to restrictions on the operating conditions of the electrostatic precipitator 1. Therefore, it is desirable that the upper limit of D1 / D2 is 2.0.

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５に電源から負電圧を印加することで、突起部５ａ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。従来の電気集塵装置の捕集原理では、帯電されたダストは、クーロン力により接地された集塵極４に引き寄せられ、集塵極４上に捕集されるとされてきたが、実際にはイオン風の影響が大きく作用している。 Next, the operation of the electrostatic precipitator 1 of the present embodiment will be described.
In the electrostatic precipitator 1, a corona discharge is generated at the tip of the protrusion 5a by applying a negative voltage to the discharge electrode 5 from a power source. The dust contained in the gas flow G is charged by the corona discharge. According to the collection principle of the conventional electrostatic precipitator, the charged dust is attracted to the grounded dust collecting electrode 4 by the Coulomb force and collected on the dust collecting electrode 4. Is greatly affected by the ion wind.

コロナ放電が発生すると、突起部５ａ近くでマイナスイオンが発生し、そのマイナスイオンが電界によって集塵極４に向けて移動し、イオン風が生じる。そのためクーロン力がダストに作用すると同時に、集塵極４に向かって流れるイオン風が、ガス流れＧに含まれるダストを放電側集塵極４ａの近傍まで移動させるように作用する。そして、放電側集塵極４ａの近傍の領域で、電界強度の持ち上がりによってクーロン力を高め、効果的にダストを集塵する。また、円形パイプとされた集塵極４を所定のガス流れＧ方向であるｘ方向に間隔をあけて配置することで、突起部５ａから放電側集塵極４ａへ向けて流れるイオン風の一部が集塵極４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４で反転されて離反する流れを抑制できるため、捕集効率が向上する。 When the corona discharge occurs, negative ions are generated near the protrusion 5a, and the negative ions move toward the dust collecting electrode 4 by the electric field, and an ionic wind is generated. Therefore, at the same time that the Coulomb force acts on the dust, the ionic wind flowing toward the dust collecting electrode 4 acts to move the dust contained in the gas flow G to the vicinity of the discharging side dust collecting electrode 4a. Then, in the region near the discharge-side dust collecting electrode 4a, the Coulomb force is increased by increasing the electric field strength, and dust is effectively collected. Further, by arranging the dust collecting poles 4 formed as circular pipes at intervals in the x direction which is the predetermined gas flow G direction, one of the ion winds flowing from the protrusion 5a toward the discharge side dust collecting pole 4a. Allows the portion to escape to the back side of the dust collecting electrode 4. As a result, the flow in which the ionic wind is reversed at the dust collecting electrode 4 and separated can be suppressed, so that the collecting efficiency is improved.

ダストを含んで集塵極４に向かって流れるイオン風の一部は、集塵極４の間を通り抜ける。イオン風は一方向に向けられるので、互いに干渉することがない。 A part of the ionic wind containing dust and flowing toward the dust collecting pole 4 passes between the dust collecting poles 4. Since the ionic winds are directed in one direction, they do not interfere with each other.

一方、突起部５ａの反対側の反対側集塵極４ｂとの間では、図６Ｂを用いて説明したように、放電極５を中央位置ＣＬからオフセットすることによって、反対側集塵極４ｂ近傍の電界強度E2maxをオフセット無しに比べて増加することができる。これにより、突起部５ａの反対側の反対側集塵極４ｂでもクーロン力によって効果的に集塵が行われる。すなわち、イオン風によって集塵極４の背面である反対側集塵極４ｂに回り込んだ未捕集ダストを効率的に捕集することができる。 On the other hand, between the protrusion 5a and the opposite side dust collecting electrode 4b, as described with reference to FIG. 6B, the emission electrode 5 is offset from the central position CL so as to be in the vicinity of the opposite side dust collecting electrode 4b. The electric field strength E2max can be increased compared to no offset. As a result, dust can be effectively collected by the Coulomb force even at the dust collecting electrode 4b on the opposite side of the protrusion 5a. That is, it is possible to efficiently collect the uncollected dust that has sneak into the opposite side dust collecting electrode 4b, which is the back surface of the dust collecting electrode 4, by the ion wind.

集塵極４に捕集されたダストは、槌打によって剥離回収される。あるいは、集塵極を移動させてブラシでダストを掻き落とす方式や、湿式洗浄を採用しても良い。 The dust collected in the dust collecting electrode 4 is peeled off and collected by hammering. Alternatively, a method of moving the dust collecting electrode and scraping off the dust with a brush, or a wet cleaning method may be adopted.

本実施形態によれば、以下の作用効果を奏する。
放電極５の本体部５ｂの中心が放電側集塵極４ａと反対側集塵極４ｂとの間の中央位置ＣＬよりも放電側集塵極４ａから遠ざかる方向に位置されているので、放電極５の本体部５ｂと反対側集塵極４ｂとが近づくことになる。これにより、放電極５の本体部５ｂと反対側集塵極４ｂとの間の電界強度を増加させることができ、反対側集塵極４ｂにおいてもクーロン力による集塵効率を高めることができる。 According to this embodiment, the following effects are exhibited.
Since the center of the main body 5b of the discharge electrode 5 is located in a direction away from the discharge side dust collection electrode 4a from the central position CL between the discharge side dust collection electrode 4a and the opposite side dust collection electrode 4b, the discharge electrode 5 is released. The main body 5b of 5 and the dust collecting electrode 4b on the opposite side come close to each other. As a result, the electric field strength between the main body 5b of the discharge electrode 5 and the opposite side dust collecting electrode 4b can be increased, and the dust collecting efficiency due to the Coulomb force can be increased also at the opposite side dust collecting electrode 4b.

なお、上述した実施形態では、放電極５の構成として、円形の横断面を有する本体部５ｂに対して突起部５ａを設けた構成としたが、図７Ａに示すように、横断面が矩形とされた角棒５ｂ’に突起部５ａを設けた構成としても良い。あるいは、図７Ｂに示すように、平板を打ち抜いて形成し、突起部５ａと本体部５ｂ”とが一体的に構成されているものであっても良い。 In the above-described embodiment, the release electrode 5 is configured to have a protrusion 5a on the main body 5b having a circular cross section, but as shown in FIG. 7A, the cross section is rectangular. A protrusion 5a may be provided on the square bar 5b'. Alternatively, as shown in FIG. 7B, a flat plate may be punched out to form the protrusion 5a and the main body 5b ”integrally.

また、図８Ａ及び図８Ｂに示すように、上述した円形パイプとした集塵極４に代えて、平板に多数の孔を形成したパンチングメタルのような平板状集塵極４’としても良い。あるいは、図９Ａ及び図９Ｂに示すように、多数の孔を形成したパンチングメタルのような平板をガス流れＧ方向に交互に規則的に折り返した折れ板状集塵極４”としても良い。この場合、放電極５の突起部５ａは、対向する折れ板の凹凸に応じてオフセットされる。 Further, as shown in FIGS. 8A and 8B, instead of the above-mentioned circular pipe dust collecting pole 4, a flat plate-shaped dust collecting pole 4'such as a punching metal having a large number of holes formed in the flat plate may be used. Alternatively, as shown in FIGS. 9A and 9B, a flat plate such as a punching metal having a large number of holes formed therein may be alternately and regularly folded back in the gas flow G direction to form a folded plate-shaped dust collecting electrode 4 ”. In this case, the protrusion 5a of the release electrode 5 is offset according to the unevenness of the opposing folded plates.

さらに、集塵極４は、金属製線材を縦方向と横方向などに交差させた織金網（例えばロッククリンプ織金網など）でもよい。織金網は、一定の開口率を有しつつ、表面にエッジがないため、集塵極４近傍の電界強度を一様に上昇させることができる。なお、金網は、織金網に限定されず、溶接金網のように断面円形状の線材を縦方向と横方向に並べて接続したものでもよい。 Further, the dust collecting electrode 4 may be a woven wire mesh (for example, a rock crimp woven wire mesh) in which a metal wire rod is crossed in a vertical direction and a horizontal direction. Since the woven wire mesh has a constant aperture ratio and no edge on the surface, the electric field strength in the vicinity of the dust collecting electrode 4 can be uniformly increased. The wire mesh is not limited to the woven wire mesh, and may be a wire mesh having a circular cross section connected in the vertical direction and the horizontal direction, such as a welded wire mesh.

電気集塵装置１が、空気浄化用に空気清浄機として用いられる場合、粒子が装置内に滞留する時間が短く、粒子濃度も低い。一方、火力発電プラントに用いられる電気集塵装置１は、空気浄化用に用いられる場合と異なり規模が大きく、粒子が滞留する時間が長く、粒子濃度も高い。空気浄化用の電気集塵装置１において、低濃度の粒子を短い滞留時間で通過させると、放電極５の突起部５ａからのイオン風によって生じるガス循環による効果で、粒子を集塵極４に捕集できない。 When the electrostatic precipitator 1 is used as an air purifier for air purification, the time for particles to stay in the device is short and the particle concentration is low. On the other hand, the electrostatic precipitator 1 used in a thermal power plant has a large scale, a long time for particles to stay, and a high particle concentration, unlike the case where it is used for air purification. In the electrostatic precipitator 1 for air purification, when low-concentration particles are passed through in a short residence time, the particles are transferred to the dust collecting electrode 4 due to the effect of gas circulation generated by the ion wind from the protrusion 5a of the discharge electrode 5. Cannot be collected.

そこで、図１２に示すように、反対側集塵極４ｂと放電極５の間のガス流れＧの上流側において、ガス遮断板６が設置されるとよい。ガス遮断板６によってガス流れＧが妨げられることにより、反対側集塵極４ｂと放電極５間に流れるガス流れの流量が低減し、集塵極４を通り抜けた粒子の滞在時間を長くして、捕集性能を高めることができる。 Therefore, as shown in FIG. 12, the gas shutoff plate 6 may be installed on the upstream side of the gas flow G between the opposite side dust collecting electrode 4b and the discharge electrode 5. By obstructing the gas flow G by the gas blocking plate 6, the flow rate of the gas flow flowing between the opposite side dust collecting electrode 4b and the discharge electrode 5 is reduced, and the residence time of the particles passing through the dust collecting electrode 4 is lengthened. , The collection performance can be improved.

１電気集塵装置
４集塵極
４ａ放電側集塵極
４ｂ反対側集塵極
５放電極
５ａ突起部（コロナ放電部）
５ｂ本体部
５ｃ取付枠
６ガス遮断板
Ｃ１（放電極の本体部の）中心
ＣＬ中央位置 1 Electrostatic precipitator 4 Dust collector 4a Discharge side dust collector 4b Opposite side dust collector 5 Discharge electrode 5a Projection (corona discharge)
5b Main body 5c Mounting frame 6 Gas cutoff plate C1 Center CL center position (of the main body of the discharge electrode)

Claims

A plurality of emission electrodes arranged along the gas flow direction, each having a main body portion and a corona discharge portion for corona discharge protruding from the main body portion,
Discharge side dust collecting poles arranged along the gas flow direction and located on the corona discharge side, and
The opposite side dust collecting electrode, which is arranged along the gas flow direction and is located on the opposite side of the discharging side dust collecting electrode across the discharging electrode,
With
The plurality of corona discharge units are arranged along the gas flow direction, and the plurality of corona discharge units are arranged.
The two corona discharge portions adjacent to each other along the gas flow direction have the same projecting direction.
The corona discharge portion projects only toward the discharge side dust collecting electrode.
The center of the main body of the discharge electrode is a first central axis which is an arrangement position passing through the center of the discharge side dust collecting electrode and a second central axis which is an arrangement position passing through the center of the opposite side dust collecting electrode. It is located in the direction away from the discharge side dust collecting electrode than the central position between them.
The discharge side dust collecting electrodes are arranged at intervals along the gas flow direction.
The opposite side dust collecting electrodes are arranged at intervals along the gas flow direction .
An electrostatic precipitator in which an ionic wind is generated only from the tip of the corona discharge portion toward the discharge side dust collecting electrode facing the discharge electrode.

A plurality of emission electrodes arranged along the gas flow direction, each having a main body portion and a corona discharge portion for corona discharge protruding from the main body portion,
Discharge side dust collecting poles arranged along the gas flow direction and located on the corona discharge side, and
The opposite side dust collecting electrode, which is arranged along the gas flow direction and is located on the opposite side of the discharging side dust collecting electrode across the discharging electrode,
With
The plurality of corona discharge units are arranged along the gas flow direction, and the plurality of corona discharge units are arranged.
The two corona discharge portions adjacent to each other along the gas flow direction have the same projecting direction.
The corona discharge portion projects only toward the discharge side dust collecting electrode.
The center of the main body of the discharge electrode is a first central axis which is an arrangement position passing through the center of the discharge side dust collecting electrode and a second central axis which is an arrangement position passing through the center of the opposite side dust collecting electrode. It is located in the direction away from the discharge side dust collecting electrode than the central position between them.
An opening is formed in each of the discharge side dust collecting electrode and the opposite side dust collecting electrode .
An electrostatic precipitator in which an ionic wind is generated only from the tip of the corona discharge portion toward the discharge side dust collecting electrode facing the discharge electrode.

The distance between the center of the main body of the discharge electrode and the first central axis of the discharge side dust collecting electrode is D1, and the center of the main body of the discharge electrode and the second of the opposite side dust collecting electrode. When the distance from the central axis is D2,
1.1 ≤ D1 / D2 ≤ 2.0
The electrostatic precipitator according to claim 1.

The plurality of the discharge side dust collecting poles and the plurality of the opposite side dust collecting poles are arranged along the gas flow direction, respectively.
D1 is the distance between the center of the main body of the discharge electrode and the first central axis of the discharge side dust collecting electrode.
The electrostatic precipitator according to claim 3, wherein the D2 is a distance between the center of the main body of the discharge electrode and the second central axis of the opposite side dust collecting electrode.

The distance between the center of the main body of the discharge electrode and the first central axis of the discharge side dust collecting electrode is D1, and the center of the main body of the discharge electrode and the second of the opposite side dust collecting electrode. When the distance from the central axis is D2,
1.1 ≤ D1 / D2 ≤ 2.0
The electrostatic precipitator according to claim 2.

According to any one of claims 1 to 5 , wherein the electric field strength between the discharge electrode and the discharge side dust collecting electrode is equivalent to the electric field strength between the discharge electrode and the opposite side dust collecting electrode. The electrostatic precipitator described.

The tip of the corona discharge portion is closer to the opposite side dust collecting electrode side than the central position between the first central axis of the discharging side dust collecting electrode and the second central axis of the opposite side dust collecting electrode. The electrostatic precipitator according to any one of claims 1 to 6, which is located.