WO2014006736A1

WO2014006736A1 - Dust-collecting device

Info

Publication number: WO2014006736A1
Application number: PCT/JP2012/067288
Authority: WO
Inventors: 一隆富松; 上田　泰稔; 小嶋　勝久; 加藤　雅也
Original assignee: 三菱重工メカトロシステムズ株式会社
Priority date: 2012-07-06
Filing date: 2012-07-06
Publication date: 2014-01-09

Abstract

Provided is a dust-collecting device capable of efficiently removing the substances to be collected. A dust-collecting device provided, in order from the upstream side, with a preliminary charging unit (3) and a bag filter in the flue through which the gas flows. Discharge electrodes (13a - 13c) and earth electrodes (12a - 12d) disposed in a direction orthogonal to the direction of gas flow are provided in the gas distribution channel (11) of the preliminary charging unit (3). The discharge electrodes (13) comprise multiple protruding discharge sections. Corona discharge is generated between a discharge electrode (13a) and the surfaces (A) facing the upstream gas side of the two earth electrodes (12a, 12b) adjacent to the discharge electrode (13a) and corona discharge is limited on the surfaces (B) facing the downstream gas side of the earth electrodes (12a, 12b).

Description

Dust collector

The present invention relates to a dust collector for removing a collection target such as dust contained in a gas, and an operation method thereof.

Conventionally, a bag filter equipped with a filter cloth for treating dust (particulate matter) contained in gas is installed. Examples of the gas include exhaust gas generated when burning coal and heavy oil, and air. The above-mentioned bag filter is installed in the flue of power generation plants such as coal-fired and heavy oil-fired, industrial combustion equipment such as incinerators, etc., as well as a dust collector that is installed in the vicinity of devices that generate dust and performs environmental dust collection Also applies.

∙ A pre-charged part may be installed in the flue upstream of the bag filter. The preliminary charging unit is a charging unit including a discharge electrode and a ground electrode, and applies positive or negative charge to the dust in the gas by corona discharge to charge the dust. The charged dust is collected on the filter cloth surface of the subsequent bag filter to form a charged dust layer. By forming a charged dust layer, fine particles entering the dust layer are attached to the coarse particles by electrostatic force. Thereby, clogging of the bag filter is reduced and the dust layer is also porous. Moreover, since coarse particles easily settle during backwashing, as a result, an increase in the pressure loss of the bag filter can be suppressed. Further, since the fine particles adhere to the coarse particles due to electrostatic force, the slipping of the fine particles through the bag filter is reduced, and as a result, the dust can be collected with high efficiency.

Patent Document 1 discloses a two-stage electrostatic precipitator including a charging unit (preliminary charging unit) and a dust collection unit. In the charging unit, the dust collecting electrode (earth electrode) having a circular shape or an equivalent shape is arranged in a polygonal shape, and the discharge electrode is arranged at the center thereof. One discharge electrode forms an electric field with a dust collecting electrode existing around the discharge electrode and charges the dust by corona discharge. The dust charged by the charging unit is collected by the downstream dust collecting unit. In the dust collector of Patent Document 1, it is only necessary to supply the dust collector with a necessary minimum current that can prevent re-scattering. Therefore, it is possible to maintain high electric field strength without causing back ionization in the dust collector. And high dust collection efficiency can be obtained.

JP-A-60-209273 (page 3, upper left column, line 11 to lower right column, line 3, FIG. 8)

However, in the electric dust collector of Patent Document 1, dust is also collected on the surface of the dust collecting electrode of the preliminary charging unit, and the electrode surface becomes dirty. In particular, when a dust collector is installed on the downstream side of a coal-fired boiler, the electrical resistivity of dust generated by the combustion of coal is high. For this reason, when corona discharge is generated between the dust collecting electrode and the discharge electrode on which dust is accumulated, a reverse ionization phenomenon is likely to occur. When the reverse ionization phenomenon occurs, ions of reverse polarity are released into the precharged portion, which causes a problem that the dust charging ability is significantly reduced.

Reverse ionization occurs when the electric field strength represented by the product (ρd × id) of the electrical resistivity (ρd) of the dust and the current density (id) flowing through the deposited dust layer exceeds the breakdown pressure of the dust layer. To do. Therefore, as one means for preventing the occurrence of reverse ionization, a method for eliminating the presence of dust itself, that is, preventing dust from accumulating on the dust collecting electrode is considered as one of the countermeasures.

In recent years, the amount of gaseous substances such as mercury in exhaust gas in a combustion facility having a coal-fired boiler may be severely limited. For this reason, it is required to effectively remove gaseous substances such as mercury in the combustion exhaust gas with a dust collector.

An object of the present invention is to provide a dust collector capable of removing a collection target with high efficiency.

One aspect of the present invention includes, in a flue through which a gas circulates, a precharge unit that discharges the collection target in the gas in order from the upstream side, and a bag filter that collects the collection target. In the dust collector, the preliminary charging unit includes a plurality of discharge electrodes arranged in a direction orthogonal to the gas flow direction in the gas flow path, and a direction orthogonal to the gas flow direction. A plurality of ground electrodes arranged, the ground electrode has a curved surface with a continuous surface facing the upstream side of the gas, and the one discharge electrode has a plurality of protruding discharge portions. The one discharge electrode is located between the two ground electrodes adjacent to each other when viewed from the upstream side of the gas, and the one discharge electrode and the two grounds closest to the one discharge electrode Corona discharge is generated between the surface of the pole facing the upstream side of the gas and the arc A surface precipitator corona discharge is inhibited by facing the downstream side of the electrode of the gas.

The collection target in the present invention is a gaseous substance such as dust or mercury contained in the combustion exhaust gas.
In the dust collector of the present invention, corona discharge is generated between the discharge electrode and the gas upstream surface of the earth electrode that is disposed on the gas downstream side of the discharge electrode and is closest to the discharge electrode. As dust passes through the corona discharge, the dust is charged. In the precharge part of the dust collector of the present invention, the ground electrode is exposed to a high-speed gas. Then, even if dust adheres to the gas upstream surface of the earth electrode due to electric force, other dust collides and the earth electrode is arranged so that dust does not accumulate on the gas upstream surface of the earth. By doing so, the cleanliness of the gas upstream surface of the ground electrode is ensured. On the other hand, charged dust is allowed to adhere to and accumulate on the gas downstream surface of the earth electrode.

In the present invention, a corona discharge is generated between one discharge electrode and the gas upstream side surface of the adjacent earth electrode. Corona discharge is suppressed on the gas downstream surface of the earth electrode. As a result, in the dust collector of the present invention, reverse ionization does not occur, and high charging ability can be maintained. Here, the state of “corona discharge is suppressed” means that reverse ionization occurs, and the charge opposite to the discharge electrode is released from the ground electrode, and the charge of the dust is neutralized to greatly increase the charging capability. It means that it is suppressed to be lowered. Preferably, there is no discharge between the discharge electrode and the gas downstream surface of the ground electrode, but it is acceptable to rarely generate back ionization to the extent that the charging capability is not significantly reduced. is there.

Further, in the gaseous substance such as mercury in the combustion exhaust gas, in the precharge portion of the dust collector of the present invention, when passing through the corona discharge generated between the discharge electrode and the ground electrode, Some are oxidized to a solid state. The substance that has become a solid state is further charged in the precharge portion. The substance in a solid state is transported to a subsequent bag filter and collected by the bag filter. In the present invention, fine particles adhere to the coarse particles by electrostatic force in the latter-stage bag filter, and an effect of reducing slipping of the fine particles in the bag filter can be obtained. For this reason, it becomes possible to collect the mercury etc. which became the solid state with high efficiency.

In the above invention, the discharge electrode has a cylindrical shape, and has one or a pair of discharge portions projecting outward in a cross section in a direction orthogonal to the axial direction, and the one or the pair of discharge portions are in the axial direction. A plurality of the discharge portions are arranged in a direction perpendicular to the gas flow direction or toward the upstream side of the gas, and the discharge portion has a tip that is closer to the gas than the center of the ground electrode. It is preferable that the discharge electrode and the ground electrode are arranged so as to be located on the upstream side.
By doing so, it is possible to prevent dust from adhering to the tip of the discharge part.

In the above invention, the ground electrode rows and the discharge electrode rows in a direction orthogonal to the gas flow direction are alternately arranged in a plurality of rows in the gas flow direction, and adjacent to each other in the gas flow direction. Preferably, the discharge electrode arranged between the poles is arranged in the center between the rows of earth electrodes, or is displaced toward the earth electrode rows on the gas downstream side. .

Charging performance can be improved by arranging a plurality of rows of ground electrodes and discharge electrodes.
In this case, if the discharge electrode arranged between the earth electrodes is shifted to the center or the gas downstream side between the earth electrodes, the discharge gas is preferentially placed between the gas upstream surface of the earth electrode on the gas downstream side and the discharge electrode. Corona discharge occurs and stable discharge is continued. On the other hand, corona discharge is suppressed between the ground electrode and the discharge electrode located on the gas upstream side. That is, corona discharge between the gas downstream surface of the earth electrode on which dust is deposited and the discharge electrode is suppressed. For this reason, high charging ability can be continued.

In the precharge unit in the dust collector of the present invention, dust is not deposited on the surface of the earth electrode that is the object of corona discharge of the discharge electrode, that is, the gas upstream surface of the earth electrode. For this reason, in the precharge part of this invention, dust can be charged, without generating reverse ionization, and high charging performance is shown.
Moreover, the dust collector of this invention can be efficiently removed by oxidizing gaseous substances, such as mercury, which exist in combustion exhaust gas, and making it change into a solid state.

It is the schematic of the dust collector which concerns on one Embodiment of this invention. It is the schematic explaining the electrode arrangement | positioning of a precharge part. It is a cross-sectional schematic diagram of an example of a discharge electrode. It is the schematic explaining another example of the electrode arrangement | positioning of a precharge part.

Hereinafter, an embodiment of a dust collector according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view of a dust collector according to the present embodiment. The dust collector 1 is installed in a flue downstream of a boiler (combustion furnace) 2 and includes a preliminary charging unit 3 and a bag filter 5 in order from the gas upstream side. The boiler 2 is a coal-fired boiler, for example. A high voltage power source 4 is connected to the preliminary charging unit 3.
An induction fan 9 and a chimney 10 are installed in the downstream flue of the bag filter 5.

In the dust collector 1 of the present embodiment, the flow rate of the flowing flue gas is in the range of 5 m / s to 20 m / s, preferably in the range of 10 m / s to 15 m / s. The dust collector 1 is installed in a flue having the above flow velocity, or a damper or the like is installed upstream of the dust collector 1 and controlled at the above flow velocity.

FIG. 2 is a schematic diagram for explaining the electrode arrangement of the preliminary charging unit of the dust collector 1. The preliminary charging unit 3 includes a plurality of ground electrodes 12a to 12d and a plurality of discharge electrodes 13a to 13c in an internal gas flow path 11.

In this embodiment, a columnar shape having a long axis is preferable. The ground electrodes 12a to 12d are curved surfaces having a continuous surface (reference A in FIG. 2) facing the gas upstream side. The shape of the surface (reference symbol B in FIG. 2) facing the gas downstream side of the earthing electrodes 12a to 12d is not particularly limited, but the earthing electrodes 12a to 12d are shaped so as not to have corners. In FIG. 2, the ground electrodes 12a to 12d are shown in a cylindrical shape, but may be in an elliptical shape. The ground electrodes 12a to 12d may be solid or hollow.

The earth electrodes 12a to 12d and the discharge electrodes 13a to 13c are made of a conductive material. For example, it is manufactured from a wear-resistant material having conductivity such as a steel material subjected to quenching treatment (specifically, S45C, SUS420J1, SCM435, etc.), chill cast iron, high chromium cast iron, hardened chromium plating treatment material, and the like. Alternatively, the surface of an inexpensive electrode material such as SS400 may be subjected to surface hardening treatment such as nitriding. Further, the earth electrodes 12a to 12d and the discharge electrodes 13a to 13c are structured so that they can be easily exchanged, and they are made of an inexpensive material with low wear resistance such as SS400, SUS304, SUS316, and periodically exchanged. It is also possible.

The discharge electrodes 13a to 13c of the present embodiment have a shape having a long axis such as a columnar shape, a prism shape, a rhomboid shape, or a flat plate shape.
FIG. 3 is a schematic cross-sectional view in a direction perpendicular to the axial direction of the discharge electrode 13 (13a to 13c) having a cylindrical shape. The discharge electrode 13 has a discharge part protruding outward. In FIG. 3, two

discharge portions

14a and 14b are formed. A plurality of

discharge portions

14a and 14b are arranged and installed along the axial direction of the

discharge electrodes

14a and 14b having a cylindrical shape.

The shape of the

discharge parts

14a and 14b has a sharp tip shape. For example, as shown in FIG. 3, each of the

discharge portions

14a and 14b has a needle shape or a conical shape whose tip is processed into a tapered shape.
The

discharge parts

14a and 14b are manufactured with a conductive material. The

discharge parts

14a and 14b may be subjected to the same wear resistance measures as the discharge electrodes 13a and 13b.

When viewed from a cross section orthogonal to the axis of the discharge electrode 13 (FIG. 3), the tips of the

discharge portions

14a and 14b are located upstream of the line passing through the center of the axis and orthogonal to the gas flow direction (the dashed line in FIG. It is attached to the discharge electrode 13 so that is located.
Furthermore, as shown in FIG. 3, the tips of the

discharge portions

14a and 14b are in a direction perpendicular to the gas flow direction (a direction in which the dashed line in FIG. 3 extends) or in a direction perpendicular to the gas flow direction. Directed upstream of the gas. When the tips of the

discharge portions

14a and 14b are installed facing the gas flow (the direction in which the tips are directed is 180 ° with respect to the gas flow direction), the

discharge portions

14a and 14b attached to the discharge electrode 13 are 1 It may be one.

The plurality of ground electrodes 12a to 12d and the plurality of discharge electrodes 13a to 13c are arranged along a direction orthogonal to the gas flow direction. When viewed from the gas upstream side, the discharge electrode 13a is arranged so as to be shifted from each other so that it is located between the two

ground electrodes

12a and 12b. Similarly, the discharge electrode 13b is positioned between the two

ground electrodes

12b and 12c, and the discharge electrode 13c is positioned between the

ground electrodes

12c and 12d.
In the present embodiment, the discharge electrodes 13a to 13c and the ground electrodes 12a to 12d are arranged so that the tips of the

discharge parts

14a and 14b are located on the gas upstream side from the centers of the ground electrodes 12a to 12d. By doing so, the discharge current to the gas upstream surface A of the ground electrodes 12a to 12d can be increased. Preferably, the discharge electrodes 13a to 13c and the ground electrodes 12a to 12d are arranged so that the tips of the

discharge portions

14a and 14b are located on the gas upstream side of the gas upstream side ends of the ground electrodes 12a to 12d. In FIG. 2, the gas downstream ends of the discharge electrodes 13a to 13c are drawn so as to be located on the gas upstream side of the gas upstream ends of the ground electrodes 12a to 12d. As long as the gas downstream side end of the discharge electrode is positioned upstream of the center of the ground electrode 12a to 12d, the gas downstream side end of the discharge electrode may be positioned downstream of the gas upstream side of the ground electrode. This is to suppress the corona discharge to the gas downstream surface B of the ground electrodes 12a to 12d if the tips of the

discharge portions

14a and 14b are located on the gas upstream side of the centers of the ground electrodes 12a to 12d. This is because you can

The

ground electrodes

12a and 12d adjacent to the wall 15 of the gas flow path and the wall 15 are preferably as close as possible to reduce the amount of gas that passes through.

Each of the ground electrodes 12a to 12d and the discharge electrodes 13a to 13c is connected to a high voltage power source 4 installed outside the precharge unit 3. The high voltage power source is DC charged. Voltages having opposite polarities are applied to the ground electrodes 12a to 12d and the discharge electrodes 13a to 13c by a high-voltage power source. The voltage application may be continuous, or may be on-off charge control (repeat voltage application and voltage application stop for a predetermined period). In order to enhance the charging effect of dust and the oxidizing effect of gaseous substances, the energy density between the discharge electrode and the earth electrode may be increased. As a specific means, there is a method of superimposing a pulsed DC high voltage on a continuous DC high voltage.

The bag filter 5 is configured by installing a filter cloth 6 for collecting dust in the gas in a dust chamber 8. The filter cloth material of the bag filter is not particularly limited as long as it can be used in a combustion exhaust gas atmosphere. Usually, PPS, PTFE, P84 or the like is adopted as the filter cloth material. In order to further improve the collection efficiency, a filter cloth with a partially or totally fine fiber diameter, a filter cloth with a PTFE membrane treatment on the surface, and a catalyst to have the ability to oxidize gaseous substances such as mercury. A supported filter cloth or the like may be employed.

In the upper part of the dust chamber 8, an upper space 7 that is separated from the dust chamber 8 through the wall above the dust chamber 8 and the filter cloth 6 is provided. The dust chamber 8 is connected to the precharging unit 3 by a flue, and the upper space 7 is connected to the induction fan 9 by the flue.

Below, the action | operation of the dust collector of this embodiment is demonstrated.
The combustion exhaust gas generated when the fuel is burned in the coal-fired boiler 2 contains gaseous substances such as dust and mercury. The combustion exhaust gas is conveyed to the preliminary charging unit 3 of the dust collector 1.

A voltage is applied to the ground electrodes 12a to 12d and the discharge electrodes 13a to 13c of the preliminary charging unit 3. For example, a negative voltage is applied to the discharge electrodes 13a to 13c, and the ground electrodes 12a to 12d are connected to the ground. As a result, corona discharge occurs between one discharge electrode 13a and the gas upstream surface A of the

ground electrodes

12a and 12b closest to the discharge electrode 13a. When the discharge electrode 13a has two

discharge portions

14a and 14b in cross section as shown in FIGS. 2 and 3, corona discharge occurs between the one discharge portion 14a and the gas upstream surface A of the ground electrode 12a. Corona discharge occurs between the other discharge portion 14b and the gas upstream surface A of the ground electrode 12b.
Similarly, with respect to the discharge electrodes 13b and 13c, similarly, a corona discharge is generated between one discharge electrode and the gas upstream surface of the ground electrode adjacent to the discharge electrode.

Combustion exhaust gas containing a collection object (a gaseous substance such as dust and mercury) generated in the boiler 2 flows into the preliminary charging unit 3. When the dust passes between the corona discharges, the dust is negatively charged. The charged dust is conveyed to a bag filter on the gas downstream side.

Some charged dust is collected by the ground electrodes 12a to 12d. Since the combustion exhaust gas circulates at a high flow velocity in the above range, even if dust is collected by the electric force on the gas upstream surface A of the earth electrodes 12a to 12d, it is blown off by collision with other dust. That is, while the gas is flowing, the gas upstream surfaces of the ground electrodes 12a to 12d are cleaned by dust. Therefore, it is possible to secure a clean surface on the gas upstream side of the ground electrodes 12a to 12d where dust is hardly attached. As a result, corona discharge is continuously generated without back ionization on the gas upstream surface of the ground electrodes 12a to 12d.
On the other hand, dust is deposited on the gas downstream surface B of the ground electrodes 12a to 12d when collected. In the present embodiment, corona discharge is suppressed on the gas downstream surface B of the ground electrodes 12a to 12d.
Therefore, corona discharge is mainly generated between the discharge electrode 13 and the gas upstream surface A of the earth electrode 12. For this reason, in the preliminary | backup charge part 3 of this embodiment, a high charging capability is maintained.

Some gaseous substances such as mercury are oxidized into solid substances when passing between the above corona discharges. For example, mercury combines with oxygen or chlorine in combustion exhaust gas to form mercury oxide (HgO) or mercury chloride (HgCl ₂ ). Mercury oxide and mercury chloride may exist as solids depending on the temperature of the flue gas flowing through the precharged part. Solidified mercury oxide and mercury chloride are charged when passing through the precharged portion.

Dust and solid substances (mercury oxide HgO, mercury chloride HgCl _2, etc.) flowing out from the precharge unit 3 flow into the dust chamber 8 of the bag filter 5 together with the combustion exhaust gas. Since the upper space 7 of the bag filter 5 is sucked by the attracting fan 9, an airflow flowing from the dust chamber 8 through the filter cloth 6 into the upper space 7 is generated. When the combustion exhaust gas passes through the filter cloth 6, charged dust and solid substances (mercury oxide HgO, mercury chloride HgCl _2, etc.) adhere to the outer surface of the filter cloth 6 and are collected.

In this embodiment, the tips of the

discharge portions

14a and 14b of the discharge electrodes 13a to 13c are directed to the direction orthogonal to the gas flow direction or the upstream side of the gas. This prevents dust from adhering to the tips of the

discharge portions

14a and 14b, as with the gas upstream surface of the ground electrodes 12a to 12d.

In the preliminary charging unit 3 of the present embodiment, a link mechanism that can rotate around the ground poles 12a to 12d may be installed. The link mechanism rotates the ground poles 12a to 12d by a predetermined angle at predetermined time intervals. When the surface on which the dust is deposited is moved to the upstream side of the gas, the deposited layer is cleaned by the collision of the dust, and a clean surface is exposed. As a result, it is possible to prevent the dust accumulation layer from growing thick.

FIG. 4 shows another example of the electrode arrangement of the precharge unit. In the preliminary charging unit 20 of FIG. 4, a plurality of rows of ground electrodes 22 and rows of discharge electrodes 23 are installed in the gas flow passage 21 in the gas flow direction. In this case, the rows of earth electrodes 22 and the rows of discharge electrodes 23 are alternately arranged. If a plurality of rows of ground electrodes 22 and discharge electrodes 23 are installed as shown in FIG. 4, dust charging performance is improved. On the other hand, even if the number of stages increases too much, the performance tends to be saturated and the pressure loss increases. For this reason, in consideration of performance and pressure loss, the number of stages of the ground electrode 22 row and the discharge electrode row 23 may be appropriately set.

When the earth electrode 22 has a cylindrical shape, if the diameter of the earth electrode 22 is d, the distance D between adjacent earth electrodes 22 in the gas flow direction is set to 2d or more. By doing so, the gas also collides with the gas upstream surface of the ground electrode 22 in the latter stage within the above flow velocity range, and the cleanliness of the gas upstream surface is maintained.

When the earth electrode 22 has a shape other than a cylinder, the distance between the earth electrodes in the gas flow direction is appropriately set so that the cleanliness of the gas upstream surface can be ensured as in the cylinder shape.

Further, as shown in FIG. 4, the rows of discharge electrodes 23 located between the rows of earth electrodes 22 indicate the distance in the gas flow direction between the center position of the ground electrode 22 and the center position of the discharge electrode 23 in the gas flow direction. When the distance in the gas flow direction between the center position of the ground electrode 22 at the rear stage and the center position of the discharge electrode 23 is L2, it is arranged so as to satisfy the relationship of L1 ≧ L2. That is, the rows of discharge electrodes 23 positioned between the rows of earth electrodes 22 are displaced in the center between the rows of earth electrodes 22 or toward the rows of the earth electrodes 22 in the subsequent stage.

Also in the precharge unit 20 of FIG. 4, the discharge electrode 23 and the ground electrode 22 are arranged so that the tip of the discharge unit is located upstream of the center of each ground electrode 22. More preferably, the discharge electrode 23 and the ground electrode 22 are arranged such that the tip of the discharge portion is located on the gas upstream side of the gas upstream end of the ground electrode 22.
Further, it is preferable that the ground electrode 22 and the wall 25 adjacent to the wall 25 of the gas flow path be as close as possible in order to reduce the amount of gas passing through.

In the precharge unit 20 of FIG. 4, when the discharge electrode 23 is located between adjacent ground electrodes 22, the gas upstream surface of the nearest ground electrode 22 located on the gas downstream side of the discharge electrode 23 and the discharge electrode 23. Corona discharge is reliably generated between the two. On the other hand, corona discharge is suppressed between the discharge electrode 23 and the surface of the earth electrode 22 located on the gas upstream side of the discharge electrode 23 on which dust is deposited (surface on the gas downstream side). 4, the corona discharge is mainly generated between the discharge electrode 23 and the gas upstream surface of the earth electrode 22. For this reason, stable charging ability is continued.

DESCRIPTION OF SYMBOLS 1 Dust collector 2 Boiler 3 Preliminary charge part 4 High voltage power supply 5 Bag filter 6 Filter cloth 7 Upper space 8 Dust chamber 9 Attraction fan 10

Chimney

11, 21

Gas distribution path

12a, 12b, 12c, 22

Ground electrode

13, 13a, 13b , 23

Discharge electrode

14a, 14b Discharge part 15.25 Wall

Claims

A dust collector comprising a precharge unit that discharges to a collection target in the gas in order from the upstream side, and a bag filter that collects the collection target in a flue through which the gas flows,
The preliminary charging unit is in the gas flow path,
A plurality of discharge electrodes arranged in a direction perpendicular to the gas flow direction;
A plurality of ground electrodes arranged in a direction perpendicular to the gas flow direction,
The ground electrode has a curved surface with a continuous surface facing the upstream side of the gas,
One discharge electrode has a plurality of protruding discharge portions,
One discharge electrode is located between the two ground electrodes adjacent to each other when viewed from the upstream side of the gas;
Corona discharge is generated between the one discharge electrode and the surfaces of the two ground electrodes closest to the one discharge electrode facing the upstream side of the gas, and on the downstream side of the gas of the ground electrode. A dust collector that suppresses corona discharge on the facing surface.
The discharge electrode has a cylindrical shape and has one or a pair of discharge portions protruding outward in a cross section in a direction orthogonal to the axial direction, and the one or a plurality of discharge portions are arranged in a plurality along the axial direction. And
The tip of the discharge part is oriented in a direction perpendicular to the gas flow direction or upstream of the gas,
2. The dust collector according to claim 1, wherein the discharge electrode and the ground electrode are arranged such that a tip of the discharge part is located upstream of the center of the ground electrode.
The ground electrode rows and the discharge electrode rows in a direction perpendicular to the gas flow direction are alternately arranged in a plurality of rows in the gas flow direction,
The discharge electrode disposed between the ground electrodes adjacent in the gas flow direction is disposed at the center between the ground electrode rows, or toward the ground electrode row on the gas downstream side. The dust collector according to claim 1, wherein the dust collector is arranged to be displaced.