JP7366366B2 - electrostatic precipitator - Google Patents

Description

The present invention relates to an electrostatic precipitator.

Conventionally, an electrostatic precipitator is known that suppresses corona discharge at the electrode end by rounding the electrode end (see, for example, Patent Document 1).
Patent Document 1 Patent No. 6274357

In an electrostatic precipitator, it is preferable to reduce power consumption.

In a first aspect of the invention, an electrostatic precipitator is provided. The electrostatic precipitator includes an inner electrode that extends in a predetermined stretching direction, and an outer electrode that is provided around the inner electrode and has an inner surface that faces the side surface of the inner electrode. The inner electrode has a first end that connects the upper surface and side surface of the inner electrode and connects the lower surface and side surface of the inner electrode. The outer electrode has a second end that connects the upper surface of the outer electrode and the inner surface, and connects the lower surface of the outer electrode and the inner surface. At least one of the first end and the second end is rounded. The radius of curvature of the roundness is 1/2 or more of the distance between the side surface and the inner surface.

In the stretching direction, the inner electrode may be longer than the outer electrode. The second end may be rounded.

In the stretching direction, the outer electrode may be longer than the inner electrode. The first end may be rounded.

The electrostatic precipitator may further include an electrode support rod connected to at least one of the first ends. The distance between the side surface and the inner surface of the electrode support rod may be 15 mm or more. The width of the inner electrode in the orthogonal direction perpendicular to the stretching direction may be 19 mm or more larger than the width of the electrode support rod in the orthogonal direction.

The electrostatic precipitator may further include a first heat storage material provided on at least a portion of the outer surface of the outer electrode. The heat capacity per unit volume of the first heat storage material may be larger than the heat capacity per unit volume of the outer electrode. The thermal conductivity of the surface of the first heat storage material may be lower than the thermal conductivity of the outer surface of the outer electrode.

The area of the outer surface of the outer electrode on which the first heat storage material is provided may be 1/2 or more of the area of the outer surface of the outer electrode.

The electrostatic precipitator may further include a second heat storage material provided inside at least a portion of the inner electrode. The heat capacity per unit volume of the second heat storage material may be smaller than the heat capacity per unit volume of the inner electrode.

The first heat storage material and the second heat storage material may maintain the temperature of the outer electrode and the temperature of the inner electrode such that the temperature of the outer electrode is higher than the temperature of the inner electrode.

The electrostatic precipitator may further include a temperature measurement unit that measures at least one of the temperature of the outer electrode and the temperature of the inner electrode. A power source may be connected to one of the inner electrode and the outer electrode, and the other may be grounded. The power source may control the voltage between the inner electrode and the outer electrode based on at least one of the temperature of the outer electrode and the temperature of the inner electrode measured by the temperature measuring section.

Note that the above summary of the invention does not list all the necessary features of the invention. Furthermore, subcombinations of these features may also constitute inventions.

It is a figure showing an example of placement of electrostatic precipitator 100 concerning one embodiment of the present invention. 1 is a perspective view showing an example of an electrostatic precipitator 100 according to an embodiment of the present invention. 3 is a diagram showing an example of an XY cross section taken along line AA' in FIG. 2. FIG. 3 is a diagram showing an example of an XZ cross section taken along line BB' in FIG. 2. FIG. 3 is a diagram showing an example of an XZ cross section taken along line BB' in FIG. 2. FIG. It is a diagram showing an example of a dust collection experimental device 300 for verifying the dust collection performance of the electrostatic precipitator 100 according to one embodiment of the present invention. 3 is a diagram showing measurement results of voltage-current characteristics of the dust collection experimental device 300. FIG. The dependence of the dust collection rate [%] on the voltage V when the electrode length L of the first electrode 332 and the second electrode 334 is 150 mm is expressed as follows: The flow velocity Vg of the gas 302 is 0.5 [m/s] to 5.0 [m/s] FIG. FIG. 7 is a diagram showing the dependence of the dust collection rate [%] on voltage V when the flow velocity Vg of gas 302 is 2.5 m/s, and when the electrode length L is 50 mm to 450 mm. FIG. 7 is a diagram showing the dependence of the dust collection rate [%] on voltage V when the flow velocity Vg of gas 302 is 1.5 m/s, and when the electrode length L is 150 mm to 750 mm. It is a perspective view showing another example of electrostatic precipitator 100 concerning one embodiment of the present invention. 12 is a diagram showing an example of an XZ cross section taken along line CC' in FIG. 11. FIG. It is a figure showing another example of electrostatic precipitator 100 concerning one embodiment of the present invention. It is a figure showing another example of electrostatic precipitator 100 concerning one embodiment of the present invention. It is a figure showing another example of electrostatic precipitator 100 concerning one embodiment of the present invention.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Furthermore, not all combinations of features described in the embodiments are essential to the solution of the invention.

FIG. 1 is a diagram showing an example of placement of an electrostatic precipitator (ESP) 100 according to one embodiment of the present invention. In this example, the electrostatic precipitator 100 is installed in a factory 200. The factory 200 is provided with a power plant 110. The power plant 110 is, for example, a motor that operates power equipment such as air conditioning equipment provided in the factory 200. The power plant 110 generates exhaust gas 120 by burning fuel. The power plant 110 may be, for example, an engine mounted on a ship or the like. The electrostatic precipitator 100 may be installed, for example, on a ship or the like.

The exhaust gas 120 includes substances such as nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter (PM). Particulate matter (PM), also called black carbon (BC), is generated by incomplete combustion of fossil fuels. Particulate matter (PM) is fine particles whose main component is carbon.

Electrostatic precipitator 100 removes particulate matter (PM) contained in exhaust gas 120. The electrostatic precipitator 100 outputs purified gas 130 from which particulate matter (PM) has been removed. In this example, the purified gas 130 is discharged to the outside of the factory 200 after passing through the exhaust pipe 140 .

FIG. 2 is a perspective view showing an example of an electrostatic precipitator 100 according to one embodiment of the present invention. The electrostatic precipitator 100 includes a dust collecting section 90 and a power source 80. The dust collecting section 90 includes a housing 40, an inner electrode 10, and an outer electrode 20. The dust collector 90 collects particulate matter (PM) contained in the exhaust gas 120.

Particulate matter (PM) contained in the exhaust gas 120 is slightly naturally charged. In order to collect this weakly charged particulate matter (PM) at a predetermined collection rate, it is preferable to apply an electric field of 10 kV/cm or more to the particulate matter (PM). Further, in order to suppress discharge in the dust collecting section 90, the electric field is preferably less than 30 kV/cm. The electrostatic precipitator 100 of this example collects weakly charged particulate matter (PM) by applying an electric field of 10 kV/cm or more and less than 30 kV/cm to the dust collecting section 90.

The power supply 80 supplies power to the dust collecting section 90 to collect the particulate matter (PM). Power supply 80 supplies voltage between inner electrode 10 and outer electrode 20. Power supply 80 may be any one of a DC power supply, an AC power supply, and a pulse power supply.

The inner electrode 10 extends in a predetermined stretching direction. Taking the inner electrode 10 as an example, the stretching direction refers to the longitudinal direction of the inner electrode 10 in the inner electrode 10 having a transverse direction and a longitudinal direction intersecting the transverse direction. In this example, the lateral direction and the longitudinal direction are orthogonal.

A power source 80 may be connected to one of the inner electrode 10 and the outer electrode 20. The other of the inner electrode 10 and the outer electrode 20 may be connected to a reference potential different from the potential set by the power source 80. The other of the inner electrode 10 and the outer electrode 20 may be grounded. In this example, a power source 80 is connected to the inner electrode 10. In this example, the outer electrode 20 is grounded. The inner electrode 10 and the outer electrode 20 may be made of metal.

In this specification, technical matters may be explained using orthogonal coordinate axes of the X-axis, Y-axis, and Z-axis. In this specification, the direction in which the inner electrode 10 extends is parallel to the Z axis, and the plane perpendicular to the Z axis is the XY plane. In this specification, a predetermined direction within the XY plane is referred to as the X-axis direction, and a direction perpendicular to the X-axis within the XY plane is referred to as the Y-axis direction.

The inner electrode 10 of this example has a cylindrical shape. The central axis of the cylinder is parallel to the Z axis. The inner electrode 10 of this example extends in the Z-axis direction. Inner electrode 10 has a side surface 12, a top surface 14, and a bottom surface 15. In this example, the side surface 12 is a side surface surrounding the central axis of the cylindrical inner electrode 10. The side surface 12 contacts the outside of the inner electrode 10 in the XY plane. Upper surface 14 and lower surface 15 intersect side surface 12 . In this example, the upper surface 14 and the lower surface 15 are perpendicular to the central axis of the inner electrode 10.

The side surface 12 may be provided with an opening 18 . The side surface 12 may be provided with a plurality of openings 18 . The plurality of openings 18 may be provided at a predetermined period in the extending direction of the inner electrode 10. A plurality of openings 18 may be provided in the arcuate side surface 12 of the inner electrode 10 in the XY plane. The inner electrode 10 may be a so-called punch metal in which a plurality of openings 18 are provided.

Inside the inner electrode 10, a hollow first collection section is provided. The outside of the inner electrode 10 and the first collection section communicate with each other through an opening 18. As described later, the electrostatic precipitator 100 may collect at least a portion of particulate matter (PM) in the first collection section. Details of the first collection section will be described later.

The upper surface 14 and the lower surface 15 of the inner electrode 10 are arranged on one side and the other side in the extending direction of the inner electrode 10, respectively. The upper surface 14 and the lower surface 15 of the inner electrode 10 refer to surfaces including one end and the other end farthest from the center of the inner electrode 10 in the extending direction, respectively. When a plurality of surfaces intersect with the side surface 12 exist on one side and the other side in the extending direction of the inner electrode 10, the surface closest to the side surface 12 among the plurality of surfaces is referred to. In this example, there is one surface that intersects with the side surface 12 on one side and the other side of the inner electrode 10 in the extending direction. The upper surface 14 and the lower surface 15 in this example are surfaces parallel to the XY plane. The upper surface 14 and the lower surface 15 may be dotted regions in any cross section parallel to the Z axis.

The outer electrode 20 may be stretched in a predetermined stretching direction. The outer electrode 20 of this example extends in the same direction as the inner electrode 10. The outer electrode 20 in this example has a cylindrical shape. The outer electrode 20 has an upper surface 24 , a lower surface 25 , an inner surface 22 and an outer surface 31 . A cavity 23 may be provided inside the outer electrode 20 . The cavity 23 in this example extends in a direction parallel to the Z axis. The cavity 23 in this example communicates with the outside of the outer electrode 20 at the upper surface 24 and lower surface 25 in the extending direction of the outer electrode 20.

The outer electrode 20 may surround at least a portion of the periphery of the cavity 23 in the XY plane. In this example, the outer electrode 20 entirely surrounds the cavity 23 in the XY plane. The outer electrode 20 of this example has a shell shape that surrounds the entire periphery of the cavity 23 . The inner surface 22 contacts the cavity 23 in the XY plane. The outer surface 31 contacts the outside of the outer electrode 20 in the XY plane.

The outer electrode 20 is provided around the side surface 12 of the inner electrode 10. The expression that the outer electrode 20 is provided around the side surface 12 refers to a state in which the outer electrode 20 is provided so as to surround at least a portion of the side surface 12 in a direction intersecting the extending direction of the inner electrode 10. In this example, the outer electrode 20 is provided so as to surround the entire side surface 12 in a direction (in the XY plane) perpendicular to the extending direction of the inner electrode 10 (direction parallel to the Z axis).

The inner surface 22 of the outer electrode 20 faces the side surface 12 of the inner electrode 10. The inner surface 22 is opposed to the side surface 12 when the cavity 23 is sandwiched between the inner surface 22 and the side surface 12 in the direction crossing the extending direction of the inner electrode 10, and the inner surface 22 and the side surface 12 are opposite to each other. refers to a state in which is in contact with the cavity 23.

In this example, the inner electrode 10 penetrates the cavity 23 in the extending direction (Z-axis direction). In the XY plane, the position of the central axis of the inner electrode 10 and the position of the central axis of the outer electrode 20 may coincide.

The inner surface 22 of the outer electrode 20 may be provided with an opening 19 . The inner surface 22 may be provided with a plurality of openings 19 . The plurality of openings 19 may be provided at predetermined intervals in the extending direction of the outer electrode 20. A plurality of openings 19 may be provided on the arcuate inner surface 22 of the outer electrode 20 in the XY plane. The outer electrode 20 may be a so-called punch metal in which a plurality of openings 19 are provided.

The housing 40 has a hollow second collection section 42 . The second collection portion 42 is in contact with the outer surface 31 of the outer electrode 20 . The outside and inside of the outer electrode 20 are communicated through the opening 19. That is, the cavity 23 and the second collection section 42 communicate with each other through the opening 19. As described later, the electrostatic precipitator 100 collects at least a portion of particulate matter (PM) in the second collection unit 42 .

The upper surface 24 and lower surface 25 of the outer electrode 20 are arranged on one side and the other side in the extending direction of the outer electrode 20, respectively. The upper surface 24 and lower surface 25 of the outer electrode 20 refer to surfaces including one end and the other end farthest from the center of the outer electrode 20 in the extending direction, respectively. When there are a plurality of surfaces intersecting the inner surface 22 on one side and the other side in the extending direction of the outer electrode 20, the surface closest to the inner surface 22 among the plurality of surfaces is referred to. In this example, there is one surface that intersects with the inner surface 22 on one side and the other side of the outer electrode 20 in the extending direction. The upper surface 24 and the lower surface 25 in this example are surfaces parallel to the XY plane. The upper surface 24 and the lower surface 25 may be dotted regions in any cross section parallel to the Z axis.

Inner electrode 10 has a first end 16 . The first end portion 16-1 is a surface disposed between the upper surface 14 and the side surface 12 in any direction within the XY plane from the central axis of the inner electrode 10 toward the side surface 12. When the direction of the surface is set to the normal direction of the surface, the direction of the first end 16-1 is different from both the direction of the top surface 14 and the direction of the side surface 12. The first end 16-1 connects the end of the top surface 14 closest to the side surface 12 and the end of the side surface 12 closest to the top surface 14 in an arbitrary cross section in a direction parallel to the Z-axis. When the top surface 14 and the side surface 12 are in contact with each other, the first end 16-1 is the vertex where the top surface 14 and the side surface 12 are connected.

The first end 16-2 is a surface disposed between the lower surface 15 and the side surface 12 in any direction within the XY plane from the central axis of the inner electrode 10 toward the side surface 12. The orientation of the first end 16-2 is different from both the orientation of the lower surface 15 and the orientation of the side surface 12. The first end 16-2 connects the end of the lower surface 15 closest to the side surface 12 and the end of the side surface 12 closest to the lower surface 15 in any cross section in the direction parallel to the Z-axis. When the lower surface 15 and the side surface 12 are in contact, the first end 16-2 is the vertex where the lower surface 15 and the side surface 12 are connected.

Outer electrode 20 has a second end 26 . The second end 26-1 is a surface disposed between the upper surface 24 and the inner surface 22 in any direction within the XY plane from the central axis of the outer electrode 20 toward the inner surface 22. The orientation of the second end 26-1 is different from both the orientation of the upper surface 24 and the orientation of the inner surface 22. The second end 26-1 connects the end of the upper surface 24 closest to the inner surface 22 and the end of the inner surface 22 closest to the upper surface 24 in any cross section in the direction parallel to the Z-axis. When the upper surface 24 and the inner surface 22 are in contact, the second end 26-1 is the vertex where the upper surface 24 and the inner surface 22 are connected.

The second end 26-2 is a surface disposed between the lower surface 25 and the inner surface 22 in any direction within the XY plane from the central axis of the outer electrode 20 toward the inner surface 22. The orientation of the second end 26-2 is different from both the orientation of the lower surface 25 and the orientation of the inner surface 22. The second end 26-2 connects the end of the lower surface 25 closest to the inner surface 22 and the end of the inner surface 22 closest to the lower surface 25 in any cross section in the direction parallel to the Z-axis. When the lower surface 25 and the inner surface 22 are in contact, the second end 26-2 is the vertex where the lower surface 25 and the inner surface 22 are connected.

In the direction in which the inner electrode 10 extends (direction parallel to the Z axis), the length of the inner electrode 10 is set to Lin. Let Lout be the length of the outer electrode 20 in the direction parallel to the Z axis. The length Lin is equal to the distance between the upper surface 14 and the lower surface 15 in the direction parallel to the Z axis. The length Lout is equal to the distance between the upper surface 24 and the lower surface 25 in the direction parallel to the Z axis.

The length Lin may be greater than the length Lout. At least one of the upper surface 14 and the lower surface 15 may be disposed outside the outer electrode 20. In this example, both the upper surface 14 and the lower surface 15 are located outside the outer electrode 20. At least one of the first end 16-1 and the first end 16-2 may be arranged outside the outer electrode 20. In this example, both the first end 16-1 and the first end 16-2 are located outside the outer electrode 20.

In this example, exhaust gas 120 discharged from power plant 110 (see FIG. 1) passes through cavity 23. In this example, the exhaust gas 120 passes through the cavity 23 in a direction parallel to the Z-axis and from the first end 16-2 to the first end 16-1. In this example, particulate matter (PM) contained in the exhaust gas 120 is collected by at least one of a first collection section (described later) and a second collection section 42 arranged inside the inner electrode 10. Ru. In this example, the purified gas 130 from which particulate matter (PM) has been removed is discharged from the cavity 23 to the outside of the electrostatic precipitator 100.

At least one of the first end 16 of the inner electrode 10 and the second end 26 of the outer electrode 20 is provided with a radius 28 . Taking the first end 16 as an example, the roundness 28 is at least a part of the first end 16 that is in contact with the outside of the inner electrode 10, and the slope of the tangent at any point on the roundness 28 is Refers to at least a portion of the first end 16 that changes continuously as a point on the radius 28 moves. In this example, the second end 26 is provided with a radius 28 and the first end 16 is not provided with a radius 28 . In this example, the roundness 28 provided at the second end 26-1 and the second end 26-2 is defined as a roundness 28-1 and a roundness 28-2, respectively.

FIG. 3 is a diagram showing an example of an XY cross section taken along line AA' in FIG. The AA' cross section is an XY cross section passing through the housing 40, the second collection section 42, the outer electrode 20, the inner electrode 10, and the cavity 23. The housing 40 has a side wall 44 . The second collection section 42 in this example is surrounded by a side wall 44 in the XY plane. Sidewall 44 has an inner surface 46. The inner surface 46 is in contact with the second collection section 42 .

A first collection section 82 is provided inside the inner electrode 10 . The inner surface 84 is the inner surface of the inner electrode 10. The inner surface 84 is in contact with the first collection section 82 .

The dust collecting section 90 collects particulate matter (PM) 50 contained in the exhaust gas 120 (see FIGS. 1 and 2) in at least one of the first collecting section 82 and the second collecting section 42 using Coulomb force. do. In FIG. 3, particulate matter (PM) 50 is indicated by black circles.

One naturally charged particulate matter (PM) 50 is charged either positively or negatively. Some of the plurality of particulate matter (PM) 50 contained in the exhaust gas 120 are positively charged, and other parts are negatively charged. Particulate matter (PM) 50 that is positively and negatively charged is referred to as particulate matter (PM) 50-1 and particulate matter (PM) 50-2, respectively. In this example, a power source 80 is connected to the inner electrode 10, and the outer electrode 20 is grounded. Therefore, particulate matter (PM) 50-1 and particulate matter (PM) 50-2 are attracted to outer electrode 20 and inner electrode 10, respectively.

Particulate matter (PM) 50-1 attracted to the outer electrode 20 moves from the cavity 23 to the second collection section 42 through the opening 19. The particulate matter (PM) 50-1 that has moved to the second collection section 42 is collected on the outer surface 31 of the outer electrode 20. Particulate matter (PM) 50-2 attracted to the inner electrode 10 moves from the cavity 23 through the opening 18 to the first collection section 82. The particulate matter (PM) 50-2 that has moved to the first collection section 82 is collected on the inner surface 84 of the inner electrode 10.

FIG. 4 is a diagram showing an example of an XZ cross section taken along line BB' in FIG. However, in FIG. 4, the X-axis and Z-axis are rotated 90 degrees around the Y-axis direction in FIG. In this example, the exhaust gas 120 passes through the cavity 23 in a direction parallel to the Z-axis and from the lower surface 25 to the upper surface 24. The dust collector 90 collects particulate matter (PM) 50 contained in the exhaust gas 120 using Coulomb force.

In this example, a voltage is applied to the inner electrode 10 in the space between the inner electrode 10 and the outer electrode 20 by a power source 80 . In this example, by applying the voltage to the space between the inner electrode 10 and the outer electrode 20, the voltage in the space between the inner electrode 10 and the outer electrode 20 is 10 kV/cm or more and less than 30 kV/cm. An electric field Ee is formed. The outer electrode 20 is grounded. As a result, when a positive voltage is applied to the inner electrode 10, an electric field Ee is generated in the cavity 23 in the direction from the inner electrode 10 to the outer electrode 20. The voltage applied to the inner electrode 10 is of positive polarity when the voltage is applied to the space between the inner electrode 10 and the outer electrode 20 in a state where the potential of the inner electrode 10 is higher than the potential of the outer electrode 20. Indicates when the voltage is applied. In FIG. 4, this electric field Ee is indicated by a thick hatched arrow.

In this example, particulate matter (PM) 50-1 and particulate matter 50-2 contained in exhaust gas 120 flowing through cavity 23 are attracted to outer electrode 20 and inner electrode 10 by electric field Ee. Particulate matter (PM) 50-1 attracted to the outer electrode 20 is collected on the outer surface 31 of the outer electrode 20. The particulate matter 50-2 attracted to the inner electrode 10 is collected on the inner surface 84 of the inner electrode 10.

FIG. 5 is a diagram showing an example of an XZ cross section taken along line BB' in FIG. FIG. 5 shows an enlarged XZ cross section of a region including the second end 26-1 of the outer electrode 20. The second end 26-1 is provided with a radius 28-1. The roundness 28 is curved in the XZ cross section. The roundness 28 in this example is arcuate in the XZ cross section. The roundness 28 in this example is curved in any cross section parallel to the Z axis. The inner surface 22 and the upper surface 24 are connected by a radius 28-1.

Let one end and the other end of one roundness 28 be one end 27 and the other end 29, respectively. In FIG. 5, one end 27 and the other end 29 are shown as black circles, but the circles merely indicate the positions of the one end 27 and the other end 29, and do not actually exist.

One end 27 of the roundness 28-1 refers to a part of the roundness 28 where the tangent at the one end 27 is parallel to the upper surface 24 of the outer electrode 20 (parallel to the XY plane). The other end 29 of the roundness 28-1 refers to a part of the roundness 28 where the tangent at the other end 29 is parallel to the inner surface 22 of the outer electrode 20 (parallel to the Z axis). The radius 28 is connected at one end 27 to the end of the upper surface 24 closest to the inner surface 22 . The radius 28 may be continuous with the top surface 24 at one end 27. The roundness 28 is connected at the other end 29 to the end of the inner surface 22 closest to the upper surface 24 . The radius 28 may be continuous with the inner surface 22 at the other end 29.

In an arbitrary cross section passing through the central axis of the inner electrode 10, the width in the direction perpendicular to the central axis (X-axis direction in FIG. 5) is defined as width W1. The width W1 is the distance between two side surfaces 12 facing each other in a direction perpendicular to the central axis. If the distance between the two side surfaces 12 is uneven in the Z-axis direction, the width W1 may be the average value of the distance between the two side surfaces 12, the maximum value, or the minimum value. It may be.

The distance between the side surface 12 and the inner surface 22, which face each other with the cavity 23 in between, is defined as a distance D1. The distance D1 is equal to the distance between the inner electrode 10 and the outer electrode 20. When the distance between the side surface 12 and the inner surface 22 is uneven in the Z-axis direction, the distance D1 may be the average value of the distance between the side surface 12 and the inner surface 22, the maximum value, or the minimum value. It may be.

Let the center of the arcuate roundness 28 in the XZ cross section be the center C. Let R be the radius of curvature of the roundness 28. In one roundness 28, the radius of curvature R may or may not be constant. If the radius of curvature R of one roundness 28 is not constant, the radius of curvature R may change continuously. In this example, the radius of curvature R is the radius of the circular arc-shaped roundness 28 centered on the center C. In this example, the radius of curvature R is constant.

In the electrostatic precipitator 100 of this example, the radius of curvature R of the roundness 28 is 1/2 or more of the distance D1. When the radius of curvature of the roundness 28 is less than 1/2 of the distance D1 and the electric field Ee of the cavity 23 is larger than 10 kV/cm, the electric field at the second end 26 is likely to be larger than 30 kV/cm. If the electric field at the second end 26 is greater than 30 kV/cm, corona discharge is likely to occur at the second end 26. When corona discharge occurs at the second end 26, the power consumption of the electrostatic precipitator 100 tends to increase. Further, when corona discharge occurs at the second end 26, ozone (O ₃ ) is likely to be generated.

In this example, since the radius of curvature R of the roundness 28 is 1/2 or more of the distance D1, even if the electric field Ee of the cavity 23 is 10 kV/cm or more and less than 30 kV/cm, the second end The electric field at 26 is unlikely to be greater than 30 kV/cm. Therefore, corona discharge is less likely to occur at the second end 26. Therefore, in the electrostatic precipitator 100 of this example, it is easier to suppress power consumption than when the radius of curvature R of the roundness 28 is less than 1/2 of the distance D1. Moreover, the electrostatic precipitator 100 of this example can more easily suppress the generation of ozone (O ₃ ) than when the radius of curvature R of the roundness 28 is less than 1/2 of the distance D1.

When the electric field Ee of the cavity 23 is greater than or equal to 10 kV/cm and less than 30 kV/cm, the particulate matter (PM) 50 passing through the cavity 23 is naturally electrically charged and forms at least one of the outer electrode 20 and the inner electrode 10. It is easy to be collected by one side. That is, the electrostatic precipitator 100 does not need to include a charging section for further charging the naturally charged particulate matter (PM) 50. Therefore, according to this example, the electrostatic precipitator 100 can be easily downsized. Moreover, according to this example, the power consumption of the electrostatic precipitator 100 can be easily suppressed.

The inner electrode 10 in this example has an end portion 86 that contacts the opening 18 . The end portion 86 is a surface disposed between the side surface 12 and the inner side surface 84 in any direction within the XY plane from the central axis of the inner electrode 10 toward the side surface 12. The orientation of the end portion 86 is different from both the orientation of the side surface 12 and the orientation of the inner surface 84. The end portion 86-1 connects the lower end of the side surface 12 in contact with the opening 18 and the lower end of the inner side surface 84 in contact with the opening 18 in an arbitrary cross section in a direction parallel to the Z-axis. The end portion 86-2 connects the upper end of the side surface 12 in contact with the opening 18 and the upper end of the inner surface 84 in contact with the opening 18 in any cross section in the direction parallel to the Z-axis.

The outer electrode 20 in this example has an end portion 96 that contacts the opening 19. The end portion 96 is a surface disposed between the outer surface 31 and the inner surface 22 in any direction within the XY plane from the central axis of the outer electrode 20 toward the outer surface 31. The orientation of the end portion 96 is different from both the orientation of the outer surface 31 and the orientation of the inner surface 22. The end portion 96 connects the lower end of the outer surface 31 in contact with the opening 19 and the lower end of the inner surface 22 in contact with the opening 19 in an arbitrary cross section in a direction parallel to the Z-axis.

Ends 86 and 96 may be provided with radii 88 and radii 98, respectively. By providing the roundness 88 and the roundness 98 at the end portion 86 and the end portion 96, respectively, even when the electric field of the cavity portion 23 is 10 kV/cm or more and less than 30 kV/cm, the inner electrode 10 can be provided at the end portion 86. The outer electrode 20 becomes less prone to corona discharge at the end 96.

FIG. 6 is a diagram showing an example of a dust collection experimental apparatus 300 for verifying the dust collection performance of the electrostatic precipitator 100 according to one embodiment of the present invention. The dust collection experimental apparatus 300 includes a fan 310, an introduction duct 320, an electrostatic precipitator 330, an exhaust duct 322, and a particle amount measurement section 340.

The electrostatic precipitator 330 has a first electrode 332 and a second electrode 334. A DC voltage V is applied to the first electrode 332 . The second electrode 334 is grounded via a resistor 338. A resistor 338 is provided to measure the current flowing between the first electrode 332 and the second electrode 334. The first electrode 332 and the second electrode 334 are provided with a radius 336-1 and a radius 336-2, respectively. The roundness 336 is arcuate.

Let L be the electrode length of the first electrode 332 and the second electrode 334 in the traveling direction of the gas 302. Let D be the distance between the first electrode 332 and the second electrode 334 in the direction perpendicular to the traveling direction of the gas 302. Let r be the radius of curvature of the roundness 336. In this example, the radius of curvature r is equal to D.

A gas 302 containing particulate matter (PM) 50 is introduced into an inlet duct 320 by a fan 310 . Let the flow velocity of the gas 302 be Vg [m/s]. The gas 302 introduced into the introduction duct 320 is introduced into the electrostatic precipitator 330. Particulate matter (PM) 50 contained in the gas 302 introduced into the electrostatic precipitator 330 is collected by the second electrode 334 between the first electrode 332 and the second electrode 334. Gas 302 becomes purified gas 304 in electrostatic precipitator 330 . After passing through the exhaust duct 322, the purified gas 302 is discharged to the outside of the dust collection experimental apparatus 300.

The particle amount measurement unit 340 measures the amount of particulate matter (PM) 50 contained in the gas 302 passing through the introduction duct 320 and the amount of particulate matter (PM) 50 contained in the purified gas 304 passing through the exhaust duct 322. Measure the amount. The particle amount measurement unit 340 of this example measures the amount of particulate matter (PM) 50 having a particle size of 0.3 μm or more.

FIG. 7 is a diagram showing measurement results of voltage-current characteristics of the dust collection experimental device 300. FIG. 7 shows the voltage-current characteristics in a state where the gas 302 is not flowing through the electrostatic precipitator 330. FIG. 7 shows the results of measuring the current Id flowing through the resistor 338 when the voltage V was varied between 0 kV and 12.5 kV. The current Id is measured with an accuracy of 0.01 μA. As shown in FIG. 7, the current Id hardly increases even if the voltage V is increased. That is, when the gas 302 is not flowing through the electrostatic precipitator 330, the electrostatic precipitator 330 consumes almost no power.

ここで、Ｅは第１電極３３２に印加される電圧であり、Ａは定数である。 FIG. 8 shows the dependence of the dust collection rate η [%] on the voltage V when the electrode length L of the first electrode 332 and the second electrode 334 is 150 mm, and the flow rate Vg of the gas 302 is 0.5 [m/s]. 5.0 [m/s]. The theoretical value of the dust collection rate η _t [%] is expressed by the following formula (1).

Here, E is the voltage applied to the first electrode 332, and A is a constant.

ここで、Ｎは浄化ガス３０４に含まれる粒子状物質（ＰＭ）５０の粒子数であり、Ｎ_０はガス３０２に含まれる粒子状物質（ＰＭ）５０の粒子数である。ガス３０２および浄化ガス３０４は、それぞれ導入ダクト３２０および排気ダクト３２２を通過する。粒子数Ｎおよび粒子数Ｎ_０は、粒子量計測部３４０により測定される。 The experimental value of the dust collection rate η [%] is expressed by the following equation (2).

Here, N is the number of particles of particulate matter (PM) 50 contained in the purified gas 304, and _N0 is the number of particles of particulate matter (PM) 50 contained in the gas 302. Gas 302 and purge gas 304 pass through inlet duct 320 and exhaust duct 322, respectively. The number N of particles and the number _N0 of particles are measured by the particle amount measuring section 340.

式（１）における定数Ａは、電圧Ｖが２．５ｋＶの場合における集塵率の実験値ηを式（３）に代入して算出されてよい。例えば、図８より、流速Ｖｇが０．５ｍ／ｓの場合において、電圧Ｖが２．５ｋＶの場合の集塵率ηは１７％である。これより、流速Ｖｇが０．５ｍ／ｓの場合の定数Ａは０．０７５と算出される。算出された定数Ａを再び（１）式へ代入することにより、他の大きさの電圧が印加された場合の集塵率が算出される。たとえば、電圧Ｖが５．０ｋＶの場合、集塵率は３１％と算出される。図８における理論値は、流速Ｖｇごとに、このようにＡを算出した結果を用いて、算出されている。 By transforming equation (1), the following equation (3) is obtained.

The constant A in equation (1) may be calculated by substituting the experimental value η of the dust collection rate when the voltage V is 2.5 kV into equation (3). For example, from FIG. 8, when the flow velocity Vg is 0.5 m/s, the dust collection rate η is 17% when the voltage V is 2.5 kV. From this, the constant A when the flow velocity Vg is 0.5 m/s is calculated to be 0.075. By substituting the calculated constant A into equation (1) again, the dust collection rate when a voltage of another magnitude is applied is calculated. For example, when the voltage V is 5.0 kV, the dust collection rate is calculated to be 31%. The theoretical values in FIG. 8 are calculated using the results of calculating A in this manner for each flow rate Vg.

FIG. 9 is a diagram showing the dependence of the dust collection rate η [%] on the voltage V when the flow velocity Vg of the gas 302 is 2.5 m/s, and when the electrode length L is 50 mm to 450 mm. The constant A of equation (1) in the theoretical value of FIG. 9 is calculated by substituting the experimental value η of the dust collection rate at a voltage V of 2.5 kV into equation (3), as in the case of FIG. 8. . For example, from FIG. 9, when the electrode length L is 450 mm, the dust collection rate η is 21% when the voltage V is 2.5 kV. From this, the constant A is calculated to be 0.094 when the electrode length L is 450 mm. By substituting the calculated constant A into equation (1) again, the dust collection rate when a voltage of another magnitude is applied is calculated. For example, when the voltage V is 5.0 kV, the dust collection rate is calculated to be 38%. The theoretical values in FIG. 9 are calculated using the results of calculating A in this manner for each flow rate Vg.

FIG. 10 is a diagram showing the voltage V dependence of the dust collection rate η [%] when the flow velocity Vg of the gas 302 is 1.5 m/s, and when the electrode length L is 150 mm to 750 mm. From FIGS. 8 to 10, the larger the voltage V, the larger the dust collection rate η becomes. From FIG. 8, the smaller the flow velocity Vg is, the larger the dust collection rate η becomes. In FIG. 8, when the flow velocity Vg is 0.5 m/s and the voltage V is 7.5 kV to 12.5 kV, the experimental value of the dust collection rate η exceeds the theoretical value. From FIG. 9, the larger the electrode length L, the larger the dust collection rate η becomes. In FIG. 9, when the electrode length L is 300 mm and the voltage V is 5.0 kV to 12.5 kV, the experimental value of the dust collection rate η exceeds the theoretical value. In FIG. 9, when the electrode length L is 450 mm and the voltage V is 12.5 kV, a dust collection rate η of 70% is obtained. As described above, the electrostatic precipitator 330 can obtain a dust collection rate η of 70% without consuming almost any power.

FIG. 11 is a perspective view showing another example of the electrostatic precipitator 100 according to one embodiment of the present invention. In the direction in which the inner electrode 10 extends (direction parallel to the Z axis), the length of the inner electrode 10 in this example is defined as Lin'. This example differs from the electrostatic precipitator 100 shown in FIG. 2 in that the length Lout of the outer electrode 20 is longer than the length Lin'. Note that in FIG. 11, the opening 19 of the outer electrode 20 is omitted.

At least one of the upper surface 14 and the lower surface 15 may be disposed inside the outer electrode 20. In this example, both the upper surface 14 and the lower surface 15 are located inside the outer electrode 20. At least one of the first end 16-1 and the first end 16-2 may be disposed inside the outer electrode 20. In this example, both the first end 16-1 and the first end 16-2 are arranged inside the outer electrode 20.

In this example, the first end 16 is provided with a radius 28 and the second end 26 is not provided with a radius 28. In this example, the upper surface 14 and lower surface 15 of the inner electrode 10 are curved surfaces. In this example, the roundness 28 provided at the first end 16-1 and the first end 16-2 is defined as a roundness 28-1 and a roundness 28-2, respectively.

The electrostatic precipitator 100 of this example includes an electrode support rod 30 at at least one of the first end 16-1 and the first end 16-2. In this example, an electrode support rod 30 is provided at the first end 16-1. The electrode support rod 30 may extend in the direction in which the inner electrode 10 extends. In this example, one longitudinal end of the electrode support rod 30 is connected to the first end 16-1. The one end of the electrode support rod 30 may be arranged at the same position as the central axis of the inner electrode 10. In this example, the other end of the electrode support rod 30 is electrically connected to a power source 80.

FIG. 12 is a diagram showing an example of an XZ cross section taken along line CC' in FIG. 11. FIG. 12 shows an enlarged XZ cross section of a region including the first end 16-1 of the inner electrode 10. The first end 16-1 is provided with a radius 28-1. The roundness 28 is curved in the XZ cross section. The roundness 28 in this example has a semicircular shape in the XZ cross section. The roundness 28 in this example is curved in any cross section parallel to the Z axis.

The center of the semicircle in the roundness 28 in this example is defined as center C'. The roundness 28 in this example has an apex 37 . The position of the vertex 37 in the XY plane may be the same as the position of the center C'.

In this example, one end of the radius 28 is the apex 37. The other end of the roundness 28 is defined as the other end 39. In FIG. 12, the apex 37 and the other end 39 are indicated by black circles, but the circles merely indicate the positions of the apex 37 and the other end 29, and do not actually exist.

The vertex 37 of the roundness 28-1 refers to a part of the roundness 28 where the tangent at the vertex 37 is parallel to the XY plane. The other end 39 of the roundness 28-1 refers to a part of the roundness 28 where the tangent at the other end 39 is parallel to the side surface 12 of the inner electrode 10 (parallel to the Z axis). In this example, the upper surface 14 is the apex 37 of the radius 28. The roundness 28 is connected at the other end 39 to the end of the side surface 12 closest to the top surface 14 . The radius 28 may be continuous with the side surface 12 at the other end 39.

The radius of curvature of the roundness 28 is defined as the radius of curvature R'. In this example, the radius of curvature R' is the radius of the circular arc-shaped roundness 28 centered on the center C'.

The electrode support rod 30 has a side surface 32. The side surface 32 is a part of the electrode support rod 30 that intersects with the XY plane in the XZ cross section of FIG. 12. In this example, the side surface 32 intersects perpendicularly with the XY plane in the XZ cross section of FIG. The side surface 32 contacts the cavity 23 in a region sandwiched between two inner side surfaces 22 facing each other in the X-axis direction in FIG. The side surface 32 may or may not be parallel to the inner surface 22 in any cross section parallel to the Z axis.

The electrode support rod 30 may have a cylindrical shape. The side surface 32 in this example is the side surface of the cylindrical electrode support rod 30. The width of the electrode support rod 30 in the orthogonal direction (in this example, any direction in the XY plane, for example, the X-axis direction) that is perpendicular to the extending direction of the inner electrode 10 is defined as a width W2. The distance between the inner side surface 22, which faces the side surface 32 with the cavity 23 in between, and the side surface 32 is defined as a distance D2. If the width of the electrode support rod 30 is nonuniform in the Z-axis direction, the width W2 may be the average value of the width of the portion of the electrode support rod 30 that is in contact with the cavity 23, and may not be the maximum value. It may be the minimum value. When the distance between the inner surface 22 and the side surface 32 is uneven in the Z-axis direction, the distance D2 may be the average value of the distance between the inner surface 22 and the side surface 32, the maximum value, or the minimum value. There may be.

Assuming that the dielectric breakdown electric field of air is Ea [kV/cm] and the corona discharge starting electric field of the electrode support rod 30 is Ec [kV/cm], in this example, the electric field Ea [kV/cm] and the electric field Ec [kV/cm] ], the applied voltage Ve' [kV] between the inner electrode 10 and the outer electrode 20, the width W2 [mm] of the electrode support rod 30, the radius of curvature R' [mm] of the roundness 28, the side surface 12 and the inner surface 22, The distance D1 [mm] between the inner surface 22 and the side surface 32 and the distance D2 [mm] between the inner surface 22 and the side surface 32 satisfy the following formula.

Here, when the electric field Ea = 30 [kV/cm] and the applied voltage Ve' = 30 [kV], the distance D1≧10.0 [mm] and the radius of curvature R'≧5.0 [mm]. When radius of curvature R' = 5.0 [mm], there is no set of width W2, distance D1, and distance D2 that satisfies equations (4-3) and (4-4), so here, radius of curvature R' =10.0 [mm].

If the electric field Ec is 30 [kV/cm], the right side of equation (4-3) is 1 [cm]. From this, when distance D1 = 10.0 [mm] and radius of curvature R' = 10.0 [mm], the range of width W2 that satisfies equations (4-3) and (4-4) is width W2 ≦10.0 [mm]. If the width W2 that satisfies the range is set as width W2=1.0 [mm], D2=19.5 [mm] from equation (4-4).

The width W1 of the inner electrode 10 in the X-axis direction may be larger than the distance D1. The distance D1 may be greater than the width W2. The radius R' may be smaller or larger than the distance D1. The radius R' may be equal to the distance D1.

The width W2 is, for example, 1.0 mm. The distance D2 may be 15 mm or more and may be less than 20 mm. The distance D1 may be 5 mm or more and 15 mm or less. In this example, the distance D1 is 10 mm.

The width W1 may be 40 mm or more larger than the width W2, and may be 60 mm or more larger than the width W2. In this example, the width W1 is 19 mm larger than the width W2. That is, in this example, the width W1 is 20 mm.

When the first end 16 is provided with a roundness 28 and the distance D1 and the distance D2 are 10 mm and 19.5 mm, respectively, even if the electric field Ee of the cavity 23 is larger than 10 kV/cm, the second Corona discharge is less likely to occur at the end portion 26. Therefore, in the electrostatic precipitator 100 of this example, the electric field in the cavity 23 can be easily set to 10 kV/cm or more and less than 30 kV/cm, similarly to the examples shown in FIGS. 2 to 5. Therefore, the electrostatic precipitator 100 of this example can easily collect particulate matter (PM) 50 passing through the cavity 23.

FIG. 13 is a diagram showing another example of the electrostatic precipitator 100 according to one embodiment of the present invention. The electrostatic precipitator 100 of this example differs from the electrostatic precipitator 100 shown in FIGS. 2 to 5 in that it further includes a first heat storage material 60. Further, the electrostatic precipitator 100 of this example differs from the electrostatic precipitator 100 shown in FIGS. 2 to 5 in that the outer electrode 20 is not provided with an opening 19. FIG. 13 is a diagram showing the first heat storage material 60 along the BB' cross section in FIG.

The first heat storage material 60 may be provided on at least a portion of the outer surface 31 of the outer electrode 20. The area of the outer surface 31 provided with the first heat storage material 60 may be 1/2 or more of the area of the outer surface 31. In this example, the first heat storage material 60 is provided on the entire outer surface 31.

The first heat storage material 60 may not be provided on the inner surface 22. Particulate matter (PM) 50-1 is collected on the inner surface 22. For this reason, it is preferable that the first heat storage material 60 is not provided on the inner surface 22.

The outer electrode 20 may be provided with an opening 19 . In this case, the first heat storage material 60 may be provided with an opening so as to communicate with the opening 19.

The heat capacity per unit volume of the first heat storage material 60 is assumed to be Cs1 [J/K·m ³ ]. Let the heat capacity per unit volume of the outer electrode 20 be Ce1 [J/K·m ³ ]. The heat capacity Cs1 may be larger than the heat capacity Ce1.

The surface of the first heat storage material 60 is referred to as a surface 62. The surface 62 refers to the surface of the first heat storage material 60 that is in contact with the outer surface 31 of the outer electrode 20. The thermal conductivity of the surface 62 is assumed to be Ks1 [W/m·K]. The thermal conductivity of the outer surface 31 of the outer electrode 20 is assumed to be Ke1 [W/m·K]. The thermal conductivity Ks1 may be smaller than the thermal conductivity Ke1.

The temperature of exhaust gas 120 discharged from power plant 110 (see FIG. 1) may be between 300°C and 400°C. Therefore, when the dust collecting section 90 comes into contact with the exhaust gas 120 at 300° C. to 400° C., problems such as burning of the wiring connected to the dust collecting section 90 may occur. Furthermore, when the dust collection section 90 comes into contact with the exhaust gas 120 at 300°C to 400°C, the temperature of the cavity 23 tends to rise, so even if the electric field of the cavity 23 is less than 30 kV/cm, the temperature of the cavity 23 is likely to rise. The air present tends to cause dielectric breakdown.

In this example, the heat capacity Cs1 is larger than the heat capacity Ce1, and the thermal conductivity Ks1 is smaller than the thermal conductivity Ke1, so the first heat storage material 60 absorbs and absorbs the heat of the exhaust gas 120 conducted to the outer electrode 20. Can store heat. Therefore, the electrostatic precipitator 100 of this example can maintain the temperature of the outer electrode 20 at a predetermined temperature T1 lower than the temperature of the exhaust gas 120 by the first heat storage material 60. The temperature T1 is, for example, 200°C or more and 300°C or less. Thereby, the electrostatic precipitator 100 of this example can suppress problems such as burning of the wiring connected to the dust collecting section 90. Further, the electrostatic precipitator 100 of this example can suppress dielectric breakdown of the air existing in the cavity 23 when the electric field in the cavity 23 is less than 30 kV/cm. In order to maintain the temperature of the outer electrode 20 at the temperature T1, the area of the outer surface 31 provided with the first heat storage material 60 is preferably 1/2 or more of the area of the outer surface 31.

The first heat storage material 60 may be a chemical heat storage material. A chemical heat storage material is a heat storage material that utilizes reaction heat accompanying a chemical reaction. Examples of the chemical heat storage material include calcium hydroxide (Ca(OH) ₂ ), magnesium hydride (MgH ₂ ), and perovskite ceramics.

Calcium hydroxide (Ca(OH) ₂ ) generates calcium oxide (CaO) and water (H ₂ O) through a dehydration reaction. This dehydration reaction is endothermic. Calcium oxide (CaO) and water (H ₂ O) produce calcium hydroxide (Ca(OH) ₂ ) through a hydration reaction. This hydration reaction is accompanied by exotherm.
[Chemical formula 1]
Ca(OH) ₂ ⇔CaO+H ₂ O
When the first heat storage material 60 is calcium hydroxide (Ca(OH) ₂ ), the temperature of the dust collecting section 90 can be maintained at the temperature T1 by this endothermic and exothermic reaction.

Magnesium hydride (MgH ₂ ) is accompanied by an endotherm when decomposed into magnesium (Mg) and hydrogen (H ₂ ). Magnesium (Mg) and hydrogen (H ₂ ) generate heat when synthesized into magnesium hydride (MgH ₂ ).
[Chemical formula 2]
_MgH2 ⇔Mg+ _H2
When the first heat storage material 60 is magnesium hydride (MgH ₂ ), the temperature of the dust collecting section 90 can be maintained at the temperature T1 by this endothermic and exothermic reaction.

Chemical heat storage materials often have a larger heat storage capacity than other heat storage materials. Therefore, when the first heat storage material 60 is a chemical heat storage material, the first heat storage material 60 is easily miniaturized. Therefore, when the first heat storage material 60 is a chemical heat storage material, the electrostatic precipitator 100 can be easily downsized. The temperature T may vary depending on the chemical heat storage material between 200°C and 300°C.

FIG. 14 is a diagram showing another example of the electrostatic precipitator 100 according to one embodiment of the present invention. The electrostatic precipitator 100 of this example differs from the electrostatic precipitator 100 shown in FIGS. 2 to 5 in that it further includes a second heat storage material 70. FIG. 14 is a diagram showing the second heat storage material 70 along the BB' cross section in FIG.

The second heat storage material 70 may be provided at least partially inside the inner electrode 10 . The second heat storage material 70 may be provided up to the outside of the outer electrode 20 in the direction parallel to the Z-axis. The second heat storage material 70 may have a cylindrical shape with the Z axis as the central axis. When the inner electrode 10 and the second heat storage material 70 are columnar, the position of the central axis of the second heat storage material 70 and the position of the central axis of the inner electrode 10 may coincide in the XY plane. In this example, the second heat storage material 70 is filled in the first collection section 82 in FIG. 3 . In this example, particulate matter (PM) 50-2 is collected on the side surface 12 of the inner electrode 10.

The heat capacity per unit volume of the second heat storage material 70 is assumed to be Cs2 [J/K·m ³ ]. Let the heat capacity per unit volume of the inner electrode 10 be Ce2 [J/K·m ³ ]. The heat capacity Cs2 may be smaller than the heat capacity Ce2.

The surface of the second heat storage material 70 is referred to as a surface 72. The surface 72 refers to the surface inside the second heat storage material 70 that is in contact with the inner electrode 10 . The thermal conductivity of the surface 72 is assumed to be Ks2 [W/m·K]. The thermal conductivity of the side surface 12 of the inner electrode 10 is assumed to be Ke2 [W/m·K]. The thermal conductivity Ks2 may be greater than the thermal conductivity Ke2.

When the inner electrode 10 collects particulate matter (PM) 50-2, when the temperature of the inner electrode 10 falls below the sulfuric acid dew point (approximately 200°C), the sulfur contained in the particulate matter (PM) 50-2 Oxides (SOx) may condense on the side surfaces 12. When sulfur oxides (SOx) condense on the side surface 12, sulfuric acid (H ₂ SO ₄ ) may be produced. When sulfuric acid (H ₂ SO ₄ ) is generated on the side surface 12, the side surface 12 may be corroded by the sulfuric acid (H ₂ SO ₄ ).

In this example, since the heat capacity Cs2 is smaller than the heat capacity Ce2 and the thermal conductivity Ks2 is larger than the thermal conductivity Ke2, the second heat storage material 70 lowers the temperature of the inner electrode 10 to a predetermined temperature T2 higher than the sulfuric acid dew point. can be maintained. Temperature T2 may be lower than temperature T1. The temperature T2 is, for example, 100°C or more and less than 200°C. Therefore, the electrostatic precipitator 100 of this example can easily suppress corrosion of the inner electrode 10 caused by sulfuric acid (H ₂ SO ₄ ). In addition, when the dust collecting section 90 collects particulate matter (PM) 50 on the side surface 12 of the inner electrode 10 as in this example, the second heat storage material 70 is provided inside the inner electrode 10 so that the electricity is The dust collector 100 can effectively utilize the area inside the inner electrode 10.

When the first heat storage material 60 is provided on the outer surface 31 of the outer electrode 20 and the second heat storage material 70 is provided in at least a portion of the inside of the inner electrode 10, the first heat storage material 60 and the second heat storage material 70 may maintain the temperature of the outer electrode 20 at temperature T1 and the temperature of the inner electrode 10 at temperature T2 so that the temperature of the outer electrode 20 is higher than the temperature of the inner electrode 10. The first heat storage material 60 and the second heat storage material 70 maintain the temperature T1 of the outer electrode 20 and the temperature T2 of the inner electrode 10 in this way, so that the wiring connected to the dust collection section 90 may burn, etc. This makes it easier to suppress corrosion of the inner electrode 10 due to sulfuric acid (H ₂ SO ₄ ) while suppressing problems and dielectric breakdown of the cavity 23.

FIG. 15 is a diagram showing another example of the electrostatic precipitator 100 according to one embodiment of the present invention. The electrostatic precipitator 100 of this example differs from the electrostatic precipitator 100 shown in FIG. 2 in that it further includes a temperature measurement section 206, a temperature sensor 210, and a temperature sensor 212. The temperature measurement unit 206 measures at least one of the temperature of the outer electrode 20 and the temperature of the inner electrode 10. In this example, the temperature measurement section 206 measures both the temperature of the outer electrode 20 and the temperature of the inner electrode 10. In this example, the temperature measuring unit 206 measures the temperature of the outer electrode 20 and the temperature of the inner electrode 10 using a temperature sensor 212 and a temperature sensor 210, respectively.

Power source 80 may control the voltage between inner electrode 10 and outer electrode 20 based on at least one of the temperature of outer electrode 20 and the temperature of inner electrode 10 . In this example, power supply 80 controls the voltage between inner electrode 10 and outer electrode 20 based on the temperature of outer electrode 20 and the temperature of inner electrode 10 .

In this example, the inner electrode 10 and the outer electrode 20 have a temperature sensor 210 and a temperature sensor 212, respectively. The inner electrode 10 and the outer electrode 20 may have multiple temperature sensors 210 and multiple temperature sensors 212, respectively. In this example, the inner electrode 10 has two temperature sensors 210 (temperature sensor 210-1 and temperature sensor 210-2), and the outer electrode 20 has two temperature sensors 212 (temperature sensor 212-1 and temperature sensor 212). -2). In this example, temperature sensor 210-1 and temperature sensor 210-2 are provided on upper surface 14 and lower surface 15 of inner electrode 10, respectively. In this example, temperature sensor 212-1 and temperature sensor 212-2 are provided on upper surface 24 and lower surface 25 of outer electrode 20, respectively.

Also in this example, the electrostatic precipitator 100 may include the first heat storage material 60 as shown in FIG. 13, and may also include the second heat storage material 70 as shown in FIG. When the inner electrode 10 and the outer electrode 20 each have one temperature sensor 210 and one temperature sensor 212, the temperature sensor 210 and the temperature sensor 212 are preferably provided on the upstream side in the flow path of the exhaust gas 120. . In this example, it is preferable that the inner electrode 10 and the outer electrode 20 have a temperature sensor 210-2 and a temperature sensor 212-2, respectively.

When the inner electrode 10 and the outer electrode 20 each have one temperature sensor 210 and one temperature sensor 212, the temperature measuring unit 206 measures the temperature of the outer electrode 20 by the temperature sensor 212-2 and the temperature sensor 210-2, respectively. and the temperature of the inner electrode 10 may be measured. The power source 80 may control the voltage between the inner electrode 10 and the outer electrode 20 based on at least one of the temperature of the outer electrode 20 and the temperature of the inner electrode 10 .

When the electrostatic precipitator 100 includes the first heat storage material 60 (FIG. 13) or the second heat storage material 70 (FIG. 14), the heat of the exhaust gas 120 is likely to be absorbed in the dust collection section 90. Therefore, the temperature of the purified gas 130 tends to be lower than the temperature of the exhaust gas 120. Therefore, the power supply 80 controls the voltage between the inner electrode 10 and the outer electrode 20 based on the temperature of the outer electrode 20 and the temperature of the inner electrode 10, so that the temperature of the inner electrode 10 is adjusted to T2 (i.e., 100° C. or more and less than 200° C.), and the temperature of the outer electrode 20 can be easily maintained at the above-mentioned T1 (ie, 200° C. or more and 300° C. or less).

When the inner electrode 10 and the outer electrode 20 have two temperature sensors 210 and two temperature sensors 212, respectively, the temperature measurement unit 206 measures the temperature of the upper surface 14 and lower surface 15 of the inner electrode 10, and the upper surface 24 and lower surface of the outer electrode. 25 temperatures can be measured. In this case, the temperature measurement unit 206 can calculate the amount of heat stored in the inner electrode 10 by comparing the temperature of the upper surface 14 and the temperature of the lower surface 15 of the inner electrode 10. Furthermore, the temperature measurement unit 206 can calculate the amount of heat stored in the outer electrode 20 by comparing the temperature of the upper surface 24 and the temperature of the lower surface 25 of the outer electrode 20.

The power supply 80 may control the voltage between the inner electrode 10 and the outer electrode 20 based on at least one of the amount of heat stored in the inner electrode 10 and the amount of heat stored in the outer electrode 20. The power source 80 may control the cycle of the voltage applied between the inner electrode 10 and the outer electrode 20 based on at least one of the amount of heat stored in the inner electrode 10 and the amount of heat stored in the outer electrode 20. The power source 80 may control the time for applying the voltage between the inner electrode 10 and the outer electrode 20 based on at least one of the amount of heat stored in the inner electrode 10 and the amount of heat stored in the outer electrode 20.

The temperature measurement unit 206 compares the amount of heat stored in the outer electrode 20 and the heat capacity of the first heat storage material 60 and determines whether the amount of heat stored in the outer electrode 20 is less than the heat capacity of the first heat storage material or It may be determined whether the amount of heat storage exceeds the heat capacity of the first heat storage material. The heat capacity per unit volume Cs1 [J/K·m ³ ] described above may be used as the heat capacity of the first heat storage material 60. If it is determined that the heat storage amount of the outer electrode 20 exceeds the heat capacity of the first heat storage material 60, the first heat storage material 60 may be removed from the outer electrode 20, and another first heat storage material 60 is replaced with the outer electrode. 20 may be attached. The first heat storage material 60 removed from the outer electrode 20 may be used for another purpose.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the range described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the embodiments described above. It is clear from the claims that such modifications or improvements may be included within the technical scope of the present invention.

The order of execution of each process, such as the operation, procedure, step, and stage in the apparatus, system, program, and method shown in the claims, specification, and drawings, is specifically defined as "before" or "before". It should be noted that they can be implemented in any order unless the output of the previous process is used in the subsequent process. Even if the claims, specifications, and operational flows in the drawings are explained using "first," "next," etc. for convenience, this does not mean that it is essential to carry out the operations in this order. It's not a thing.

DESCRIPTION OF SYMBOLS 10... Inner electrode, 12... Side surface, 14... Upper surface, 15... Lower surface, 16... First end, 18... Opening, 20... Outer electrode, 22... -Inner surface, 23...Cavity part, 24...Top surface, 25...Bottom surface, 26...Second end, 27...One end, 28...Roundness, 29...Other end , 30... Electrode support rod, 31... Side surface, 32... Side surface, 37... Apex, 39... Other end, 40... Housing, 42... Second collection part , 44... Side wall, 46... Inner surface, 60... First heat storage material, 62... Surface, 70... Second heat storage material, 72... Surface, 80... Power source, 82... First collection part, 84... Inner surface, 86... End, 88... Roundness, 90... Dust collection part, 100... Electrostatic precipitator, 110... - Power unit, 120... Exhaust gas, 130... Purified gas, 140... Exhaust pipe, 200... Factory, 206... Temperature measuring section, 210... Temperature sensor, 212... Temperature Sensor, 300... Dust collection experiment device, 302... Gas, 304... Purifying gas, 310... Fan, 320... Introducing duct, 322... Exhaust duct, 330... Electric collector Dust part, 332... First electrode, 334... Second electrode, 336... Roundness, 338... Resistance, 340... Particle amount measurement part

Claims (11)

an inner electrode extending in a predetermined stretching direction;
an outer electrode provided around the inner electrode and having an inner surface facing a side surface of the inner electrode;
Equipped with
The inner electrode has a first end that connects the upper surface of the inner electrode and the side surface, and connects the lower surface of the inner electrode and the side surface,
The outer electrode has a second end that connects the upper surface of the outer electrode and the inner surface, and connects the lower surface of the outer electrode and the inner surface,
At least one of the first end and the second end is rounded,
The radius of curvature of the roundness is 1/2 or more of the distance between the side surface and the inner surface,
Electrostatic precipitator. In the stretching direction, the inner electrode is longer than the outer electrode,
The second end portion is provided with the roundness.
The electrostatic precipitator according to claim 1. In the stretching direction, the outer electrode is longer than the inner electrode,
The first end portion is provided with the roundness.
The electrostatic precipitator according to claim 1. further comprising an electrode support rod connected to at least one of the first ends,
The distance between the side surface of the electrode support rod and the inner surface is 15 mm or more,
The width of the inner electrode in the orthogonal direction perpendicular to the stretching direction is 19 mm or more larger than the width of the electrode support rod in the orthogonal direction.
The electrostatic precipitator according to claim 3. further comprising a first heat storage material provided on at least a portion of the outer surface of the outer electrode,
The heat capacity per unit volume of the first heat storage material is larger than the heat capacity per unit volume of the outer electrode.
The electrostatic precipitator according to any one of claims 1 to 4. The electrostatic precipitator according to claim 5, wherein the thermal conductivity of the surface of the first heat storage material is lower than the thermal conductivity of the outer surface of the outer electrode. The electrostatic precipitator according to claim 5 or 6 , wherein the area of the outer surface of the outer electrode on which the first heat storage material is provided is 1/2 or more of the area of the outer surface of the outer electrode. further comprising a second heat storage material provided in at least a portion of the inside of the inner electrode,
The heat capacity per unit volume of the second heat storage material is smaller than the heat capacity per unit volume of the inner electrode.
The electrostatic precipitator according to any one of claims 5 to 7 . The electrostatic precipitator according to claim 8, wherein the thermal conductivity of the surface of the second heat storage material is higher than the thermal conductivity of the side surface of the inner electrode. 9. The first heat storage material and the second heat storage material maintain the temperature of the outer electrode and the inner electrode such that the temperature of the outer electrode is higher than the temperature of the inner electrode. or the electrostatic precipitator described in 9 . a power source that supplies voltage between the inner electrode and the outer electrode;
a temperature measurement unit that measures at least one of the temperature of the outer electrode and the temperature of the inner electrode;
Furthermore,
The power source controls a voltage between the inner electrode and the outer electrode based on at least one of the temperature of the outer electrode and the temperature of the inner electrode measured by the temperature measurement unit.
The electrostatic precipitator according to any one of claims 1 to 10 .

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