WO2021060886A1

WO2021060886A1 - Fine dust reducing apparatus

Info

Publication number: WO2021060886A1
Application number: PCT/KR2020/012999
Authority: WO
Inventors: 이상우; 허재정; 박강희; 최준성; 권순종
Original assignee: 주식회사 누리플랜; 유니슨에이치케이알 주식회사
Priority date: 2019-09-27
Filing date: 2020-09-24
Publication date: 2021-04-01

Abstract

According to the present invention, provided is a fine dust reducing apparatus comprising: a housing which has a container structure and provides a fluid movement space having an inlet through which a fine dust-containing exhaust gas flows in and an outlet through which a fluid removed of fine dust is discharged; a diffusion means which is provided behind the inlet inside the housing and ensures that the exhaust gas moving into the inlet is diffused with respect to the internal cross-section of the housing; a demister filter means which is provided behind the diffusion means and adsorbs and removes pollutants contained in the exhaust gas diffused within the housing; a condensation filter means which is provided behind the demister filter means and ensures that fine dust contained in the exhaust gas being discharged toward the outlet is adsorbed and removed as the exhaust gas condenses or becomes condensate; and an exhaust means which is configured to communicate with the outlet and discharges to the outside only the fluid from which the pollutant and the fine dust have been removed.

Description

Fine dust reduction device

The present invention relates to a fine dust reduction device, and more particularly, fine dust reduction capable of being removed by condensation or condensation by a plurality of filtering means after fine dust particles generated from a boiler at an industrial site enter the housing. It relates to the device.

In general, a large amount of fine dust is contained in exhaust gas exhausted from an exhaust chimney configured in an industrial facility such as an LNG heating facility installed in a combined heat and power plant or a large building, and an industrial facility such as a manufacturer or a steel mill.

Accordingly, in order to remove or reduce the fine dust as described above, a fine dust reduction device has been disclosed in Patent No. 10-1126022 or the like.

Here, the conventional fine dust reduction device has a configuration in which exhaust gas including fine dust introduced to the bottom of the housing of a vertical cylindrical structure is discharged to the top, and at this time, water is injected into the exhaust gas into the interior of the housing. After allowing the enemy to grow, an injection unit or the like is configured to settle.

However, the conventional fine dust reduction device has a structure in which the housing has a vertical cylindrical structure, and at this time, water is sprayed into the exhaust gas moving from the bottom of the housing to the top, so the movement speed of the exhaust gas is fast. When the amount is large, there is a problem that the fine dust particles are discharged to the outside without being completely removed.

Accordingly, it is an object of the present invention to provide a fine dust reduction device capable of removing fine dust particles of exhaust gas generated in industrial sites while being condensed or condensed by a plurality of filtering means after flowing into a horizontal or vertical housing. will be.

Meanwhile, the object of the present invention is not limited to the above-mentioned object, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

According to the present invention, a housing having a cylindrical structure and providing a fluid movement space through which exhaust gas including fine dust is introduced through an inlet and a fluid from which fine dust is removed is discharged through an outlet; A diffusion means configured at a rear end of the inlet inside the housing and allowing exhaust gas to be moved into the inlet to diffuse with respect to the inner end face of the housing; A demister filter unit configured at a rear end of the diffusion unit and configured to adsorb and remove pollutants contained in the exhaust gas diffused inside the housing; A condensation filter unit configured at a rear end of the demister filter unit and configured to adsorb and remove fine dust while condensing or condensing exhaust gas including fine dust discharged toward the outlet; And an exhaust means configured to communicate with the outlet and allow only the fluid from which pollutants and fine dust have been removed to be discharged to the outside.

Here, the housing includes an inlet in which an inlet is formed; An outlet in which an outlet is formed; And a main body communicating the inlet and the outlet.

In addition, it is preferable that the housing has a dual structure of an inner case and an outer case in which the insulator is filled.

In addition, it is preferable that the diffusion means include a puff plate installed while covering the entire front end at at least one of the inside of the inlet or the start end of the main body communicating with the inlet.

In addition, the demister filter means, a frame having a rectangular frame structure; A mesh covering the front and rear surfaces of the frame having a rectangular frame structure and allowing exhaust gas to pass through the front and rear surfaces of the frame; And a demister filter that is filled in the hollow of the frame provided through the frame and the mesh so that pollutants in the exhaust gas passing through the mesh are adsorbed and removed.

In addition, the condensation filter means, a frame having a rectangular frame structure; A perforated plate covering the front and rear surfaces of the frame having a rectangular frame structure and allowing exhaust gas to pass through the front and rear surfaces of the frame through a plurality of through holes; And it is preferable to include a condensation filter that is filled in the hollow of the frame provided through the frame and the perforated plate and the exhaust gas penetrating through the perforated plate is condensed or condensed so that fine dust particles are adsorbed and removed.

Therefore, according to the present invention, after the fine dust particles of the exhaust gas generated in the industrial site are introduced into the horizontal or vertical housing, it can be removed while condensing or condensation by a plurality of filtering means.

Meanwhile, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a perspective view showing a fine dust reduction device according to a preferred embodiment of the present invention;

2 is a view showing a state in which the demister filter and the condensation filter are detached in the fine dust reduction device of FIG. 1;

3 to 5 are a plan view, a front view, and a rear view showing the fine dust reduction device of FIG. 1, respectively; And

6 and 7 are views showing the appearance of the demister filter and the condensation filter, respectively.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 7, the fine dust reduction device according to a preferred embodiment of the present invention has a cylindrical structure, exhaust gas including fine dust is introduced through an inlet of one end, and fine dust is introduced through an outlet of the other end. The housing 110 provides a fluid movement space through which the removed fluid is discharged, and the exhaust gas that is configured at the rear end of the inlet port inside the housing 110 and moves into the inlet port is spread evenly with respect to the inner end face of the housing 110. Diffusion means 120 to maximize the effect of reducing fine dust using the filtration means described below, dust, odor and moisture contained in the exhaust gas, which is configured at the rear end of the diffusion means 120 and diffused into the housing 110, etc. The demister filter means 130 for adsorbing and removing the same contaminants, and the exhaust gas including the fine dust discharged toward the outlet is configured at the rear end of the demister filter means 130, and the fine dust is adsorbed and removed as the exhaust gas is condensed or condensed. Exhaust means 150 configured to be in communication with the condensation filter means 140 and the outlet to allow only the fluid from which pollutants and fine dust have been removed through the demister filter means 130 and the condensation filter means 140 to be discharged to the outside. ), etc.

The housing 110 is a means for providing a space in which the constituent parts are compactly installed and configured, and an inlet 111 having a cylindrical structure in which an inlet is formed and a diameter increases gradually, and a cylindrical structure in which an outlet is formed and a diameter decreases gradually. The outlet 112 and the inlet 111 and the outlet 112 communicate with each other and are divided into a main body 113 having a rectangular cylindrical structure, and the components are easily installed and maintained through the main body 113 having a rectangular cylindrical structure. Make it possible.

In addition, the housing 110 has a dual structure of an inner case and an outer case in which the inlet 111, the outlet 112 and the main body 113 are filled with an insulator, and the temperature of the exhaust gas is directly transferred to the outer case through the insulator. It is good to prevent safety accidents such as burns of workers by preventing transmission.

In addition, the housing 110 includes an opening 114 for inserting a demister filter that enables the detachment of the demister filter unit 130 described later, and a condensation filter insert that enables the detachment of the condensation filter unit 140 described later. For the opening 115, the guide member 116 for facilitating the insertion of the demister filter means 130 and the condensation filter means 140 through the opening, and the diffusion means 120 mounted on the housing 110, It further includes a plurality of doors (not shown) that enable maintenance of the mist filter means 130 and the condensation filter means 140 and maintenance of the space between the constituent parts.

Therefore, according to the housing 110, by providing a structure in which the exhaust gas is liquefied and condensed or condensed, it is possible to prevent the exhaust gas from flowing backward even if it has a horizontal or vertical structure.

The diffusion means 120 is a diffusion member configured at the rear end of the inlet inside the housing 110 and allowing the exhaust gas moving inside the inlet to spread evenly over the inner end face of the housing 110, and communicates with the rear end of the boiler of an industrial facility. The puff plate 121 is installed while covering the front end at at least one of the inside of the inlet 111 to which the pipe is fastened or the start end of the main body 113 communicating with the inlet 111 Includes.

Here, when the puff plate 121 is configured inside the inlet 111, it may have a disk shape having a plurality of through holes, and when configured inside the start end of the main body 113, the puff plate 121 has a plurality of through holes. It may have a square plate shape.

Therefore, according to the diffusion means 120, the moving speed of the exhaust gas flowing into the housing 110 is temporarily decelerated at the front end of the puff plate 121, and then puffed through the through holes evenly perforated in the puff plate 121. By moving to the rear end of the plate 121, the exhaust gas can be spread evenly in the inner space of the housing 110, and the demister filter means 130 and the condensation filter means 140 are suppressed by deflection of the exhaust gas. The filtration efficiency using can be improved.

On the other hand, according to the present invention, the puff plate 121 has a problem in that corrosion occurs due to condensation of moisture in the exhaust gas when used for a long time, and when corrosion occurs, the through hole becomes large, thereby reducing the deflection suppression efficiency. It is preferable that the composite polymer composition is coated on the surface.

Here, the composite polymer composition is added and mixed with 50 to 60 parts by weight of a filler to 100 parts by weight of the polymer, and the polymer is a silicone resin, an epoxy resin, an acrylic resin, and a mixture thereof And it is selected from the group consisting of the copolymer, the filler includes a first filler having a first average particle diameter, a second filler having a second average particle diameter, and a third filler having a third average particle diameter, and the first average The particle diameter value is 10 to 30 μm, which is larger than the remaining average particle diameter values, the second average particle diameter value divided by the first average particle diameter value is 0.17 to 0.26, and the third average particle diameter value divided by the first average particle diameter value Is 0.09 to 0.11, the first filler, the second filler, and the third filler have an average value of short diameter/long diameter of 0.6 to 0.8, and the percentage of the sum of the mass of the second filler / the sum of the mass of the first filler is 11 to 16, or The percentage of the sum of the mass of the third filler/the sum of the mass of the first filler is 4.2 to 5.2, and the first filler, the second filler, and the third filler are alumina (Al2O3), boron nitride (BN), aluminum nitride (AlN), It is selected from the group consisting of silicon nitride (Si3N4), magnesia (MgO), beryllia (BeO), zinc oxide (ZnO), silicon carbide (SiC), zirconia (ZrO2), and mixtures thereof.

Here, 50 to 60 parts by weight of the filler is added to 100 parts by weight of the polymer. When the filler is less than the part by weight, the thermal conduction efficiency decreases, and when the amount exceeds the part by weight, the viscosity range cannot be maintained, so that the puff plate 121 ), since there is a problem that the workability is deteriorated when coating the surface, it is good to have the critical significance as described above.

In addition, the first filler, as the largest filler among fillers, has an average particle diameter in the range of 10 to 30 µm. If it is out of the range, the puff plate 121 can maintain an appropriate viscosity range when mixing with the polymer. When coating on the surface of, it is possible to secure workability and finally the surface of the puff plate 121 can be kept smooth, so it is good to have the critical significance as described above.

In addition, the second filler fills the space between the polymer and the first filler, and has an average particle diameter corresponding to 0.17 to 0.26 by dividing the second average particle diameter value by the first average particle diameter value. If it does not have a particle diameter, it may not come into contact with the first filler and are separated from each other, thereby deteriorating the heat conduction property. Therefore, it is preferable to have the critical significance as described above.

In addition, the third filler fills the space between the first filler and the second filler, and a value obtained by dividing the third average particle diameter value by the first average particle diameter value has an average particle diameter corresponding to 0.09 to 0.11, wherein the If it does not have the same average particle diameter, it is not possible to contact the first filler and is separated from each other, thereby deteriorating the heat conduction property, so it is good to have the critical significance as described above.

In addition, the first filler, the second filler, and the third filler preferably have an average value of short diameter/long diameter of 0.6 to 0.8, and if they do not have the average value of the short diameter/long diameter as described above, the space between the large filler particles is completely filled. It is good to have the critical significance as described above, since the thermal conductivity may be deteriorated due to the loss.

In addition, the percentage of the sum of the mass of the second filler / the mass of the first filler is 11 to 16, or the percentage of the sum of the mass of the third filler / the mass of the first filler is 4.2 to 5.2, and the mass ratio as described above is If not, the small filler is not added only enough to fill the space formed by the large filler, but large or small fillers are added so that the large filler may be separated from each other and the heat conduction property may be deteriorated. Therefore, it is preferable to have the critical significance as described above.

Accordingly, when the above-described composite polymer composition is coated on the puff plate 121, the moisture in the exhaust gas is prevented from condensation or condensation on the surface of the puff plate 121, thereby preventing corrosion of the puff plate 121. .

The demister filter means 130 is a means configured at the rear end of the diffusion means 120 to adsorb and remove pollutants such as dust, odor and moisture contained in the exhaust gas diffused inside the housing 110, The frame 131 of the square frame structure, which is detachable in a sliding structure into the interior of the main body 113 through the opening 114 for inserting the demister filter opened and closed at one side of the front end of the housing 110, the frame of the square frame structure (131) Filling in the hollow of the frame 131 provided through the mesh 132 and the frame 131 and the mesh 132 to cover the front and rear surfaces and allow exhaust gas to pass through the front and rear surfaces of the frame 131 And a demister filter 133 having a porous structure so that pollutants are adsorbed and removed from the exhaust gas passing through the mesh 132.

Here, the demister filter means 130 may be configured with a handle panel 134 that facilitates detachment using the opening 114 at one side of the frame 131, and the frame when the handle panel 134 is detached. Through the structure in which the hollow of 131 is opened and closed, it is possible to facilitate maintenance such as replacement or washing of the demister filter 133 filled therein.

Therefore, according to the demister filter unit 130, contaminants such as dust, odor and moisture contained in the exhaust gas diffused inside the housing 110 are adsorbed and removed, so that the efficiency of removing or reducing fine dust can be improved. have.

The condensation filter means 140 is configured at the rear end of the demister filter means 130 and is a means for adsorbing and removing the fine dust while condensing or condensing exhaust gas including fine dust discharged toward the outlet. ) A frame 141 having a square frame structure, which is detachable in a sliding structure inside the main body 113 through an opening 115 for inserting a condensation filter opened and closed at one side of the front end of the main body 113, and the front of the frame 141 having a square frame structure A perforated plate 142 and a frame 141 provided through the frame 141 and the perforated plate 142 to cover the and rear surfaces and allow exhaust gas to pass through the front and rear surfaces of the frame 141 through a plurality of through holes 142a And a condensation filter 143 that is filled in the hollow of the hole and penetrates through the perforated plate 142 so that the exhaust gas is condensed or condensed to adsorb and remove fine dust particles.

Here, the condensation filter means 140 may be configured with a handle panel 144 that facilitates detachment by using the opening 114 on one side of the frame 141, and when the handle panel 144 is detached, the frame ( Through the structure in which the hollow of 141) is opened and closed, it is possible to facilitate maintenance such as replacement or washing of the condensation filter 143 filled therein.

In addition, the condensation filter unit 140 may be configured such that a plurality of the rear end of the demister filter unit 130 are spaced at regular intervals to maximize the effect of removing or reducing fine dust.

In addition, the condensation filter 143 and the perforated plate 142 preferably have a metal material capable of maintaining a relatively low temperature through a low thermal conductivity in order to liquefy the exhaust gas having a high temperature state.

Therefore, according to the condensation filter means 140, when the exhaust gas diffused inside the housing 110 contacts the perforated plate 142 and the condensation filter 143 at a relatively low temperature, it is adsorbed and removed as condensation or condensation. Can be removed.

On the other hand, according to the present invention, the perforated plate 142 has a problem in that corrosion is generated due to condensation of moisture in the exhaust gas when used for a long time, and the through hole increases when corrosion occurs, thereby reducing the deflection suppression efficiency. It is preferred that the polymer composition is coated on the surface.

Here, since the composite polymer composition is the same as that coated on the surface of the puff plate 121, a detailed description will be omitted.

The exhaust means 150 is a means configured to communicate with the outlet of the outlet 112 and to discharge only the fluid from which contaminants and fine dust have been removed through the demister filter means 130 and the condensation filter means 140 As an example, an exhaust housing 151 fastened to the outlet 112 and a blower fan 152 configured inside the exhaust housing 151 to allow exhaust gas to flow into and out of the housing 110 are included.

Therefore, according to the exhaust means 150, the exhaust gas of the industrial facility is introduced into the inlet 111 of the housing 110, and then pollutants and fine dust are reduced in the main body 113, and then through the outlet 112. Only the fluid from which fine dust has been removed can be exhausted.

On the other hand, in the present invention, the condensation filter 143 of the condensation filter means 140, for example, in a state in which the adsorption filter having a metal material and high elasticity is filled in the hollow of the frame 141, the exhaust means 150 When the blowing fan 152 of) is operated, it is preferable to have a state in which the density is increased by being compressed and compressed toward the blowing fan 152, that is, toward the traveling direction of the exhaust gas, through which the exhaust gas is condensed or condensed. It is better to maximize the adsorption efficiency.

On the other hand, in the present invention, the diffusion means 120 further comprises an opening and closing means for selectively opening and closing the through hole of the puff plate 121 after measuring whether the exhaust gas is evenly distributed inside the housing 110. It is preferable, and through this, it is preferable to maximize the filtration efficiency by suppressing deflection of the exhaust gas as much as possible.

The opening/closing means is, for example, an area of a portion where the exhaust gas is deflected while the opening/closing panel having a size corresponding to any one area is rotated by the rotating means in a state in which the puff plate 121 is divided into a plurality of constant areas. It may be configured to selectively close and open the rest.

In addition, in the present invention, through the perforated plate 142 of the condensation filter unit 140 is zigzag attached to the inside or outside of the cooling pipe through which the refrigerant is circulated, the perforated plate 142 has a low temperature. It is preferable to maximize the efficiency of removing or reducing fine dust by allowing condensation or condensation through liquefaction of exhaust gas through this.

In addition, when the perforated plate 142 is conducted at a low temperature through the cooling pipe as described above, the perforated plate 142 is rapidly cooled through the high thermal conductivity of the composite polymer composition, so that the efficiency of removing or reducing fine dust can be maximized. .

Hereinafter, the operation of the fine dust reduction device having the configuration as described above will be described as follows.

First, after the housing 110 is positioned in a horizontal or vertical structure at a location where exhaust gas is generated, a pipe communicating with the rear end of the boiler of an industrial facility is fastened to the inlet 111, and the outlet 112 is an exhaust means. 150 is fastened, and in this state, exhaust gas including fine dust is introduced into the inlet 111 of the housing 110 as the blowing fan 152 of the exhaust means 150 is driven.

Thereafter, the exhaust gas is evenly diffused into the housing 110 by the inlet 111 of the housing 110 or the diffusion means 120 configured at the front end of the main body 113 of the housing 110.

Thereafter, contaminants such as dust, odor and moisture contained in the exhaust gas diffused into the housing 110 are adsorbed and removed by the demister filter unit 130 configured at the rear end of the diffusion unit 120.

Thereafter, the exhaust gas including fine dust discharged toward the outlet 112 by the condensation filter unit 140 configured at the rear end of the demister filter unit 130 is condensed or condensed, so that the fine dust is adsorbed and removed.

Thereafter, only the fluid in which pollutants and fine dust are reduced by the exhaust means 150 is exhausted to the outside of the housing 110.

Therefore, according to the present invention, after allowing droplets of exhaust gas flowing into the housing 110 of a horizontal or vertical cylindrical structure to grow, fine dust is absorbed by condensation or condensation in the filtering means inside the housing 110. It can be quickly removed and the backflow of exhaust gas can be prevented.

In the above-described present invention, specific embodiments have been described, but various modifications may be implemented without departing from the scope of the present invention. Therefore, the scope of the invention should not be determined by the described embodiments, but should be defined by the claims and the equivalents of the claims.

Claims

A housing 110 having a cylindrical structure and providing a fluid movement space through which exhaust gas including fine dust is introduced through an inlet and a fluid from which fine dust is removed is discharged through an outlet;

A diffusion means 120 configured at a rear end of the inner inlet of the housing 110 and allowing exhaust gas to be moved into the inlet to diffuse with respect to the inner end face of the housing 110;

A demister filter unit 130 configured at the rear end of the diffusion unit 120 and configured to adsorb and remove pollutants contained in the exhaust gas diffused inside the housing 110;

A condensation filter unit 140 configured at a rear end of the demister filter unit 130 and configured to adsorb and remove the fine dust while condensing or condensing exhaust gas including fine dust discharged toward the outlet; And

A fine dust reduction device comprising an exhaust means 150 configured to communicate with the discharge port and discharge only the fluid from which pollutants and fine dust have been removed to the outside.
The method of claim 1, wherein the diffusion means 120,

A device for reducing fine dust, comprising a puff plate 121 installed while covering at least one front end of the housing 110.
The method of claim 2, wherein the puff plate 121,

A composite polymer composition to prevent corrosion is coated on the surface,

The composite polymer composition,

50 to 60 parts by weight of a filler is added and mixed to 100 parts by weight of the polymer, and the polymer is from the group consisting of a silicone resin, an epoxy resin, an acrylic resin, a mixture thereof, and a copolymer thereof. It is selected, and the filler includes a first filler having a first average particle diameter, a second filler having a second average particle diameter, and a third filler having a third average particle diameter, and the first average particle diameter value is 10 to 30 μm. It is greater than the remaining average particle diameter values, the second average particle diameter value divided by the first average particle diameter value is 0.17 to 0.26, the third average particle diameter value divided by the first average particle diameter value is 0.09 to 0.11, and the first 1 filler, 2nd filler and 3rd filler have an average value of short/long diameter of 0.6 to 0.8, and the percentage of the sum of the masses of the second fillers/the mass of the first fillers is 11 to 16, or the sum of the masses of the third fillers The percentage of the sum of the mass of 1 filler is 4.2 to 5.2, and the first filler, the second filler, and the third filler are alumina (Al2O3), boron nitride (BN), aluminum nitride (AlN), silicon nitride (Si3N4), and magnesia (MgO). ), beryllia (BeO), zinc oxide (ZnO), silicon carbide (SiC), zirconia (ZrO2), and a fine dust reduction device, characterized in that selected from the group consisting of a mixture thereof.
The method of claim 1, wherein the demister filter means (130),

Frame 131 of a rectangular frame structure;

A mesh 132 covering the front and rear surfaces of the frame 131 having a rectangular frame structure and allowing exhaust gas to pass through the front and rear surfaces of the frame 131;

A demister filter 133 filled in the hollow of the frame 131 provided through the frame 131 and the mesh 132 so that pollutants are adsorbed and removed from the exhaust gas passing through the mesh 132; And

A device for reducing fine dust, comprising a handle panel 134 configured on one side of the frame 131 to allow the frame 131 to be inserted and detached from the housing 110.
The method of claim 1, wherein the condensation filter means 140,

Frame 141 of a square frame structure;

A perforated plate 142 covering the front and rear surfaces of the frame 141 having a rectangular frame structure and allowing exhaust gas to pass through the front and rear surfaces of the frame 141 through a plurality of through holes 142a;

A condensation filter 143 that fills the hollow of the frame 141 provided through the frame 141 and the perforated plate 142 and allows the exhaust gas penetrating through the perforated plate 142 to be condensed or condensed so that fine dust particles are adsorbed and removed. ); And

A fine dust reduction device comprising a handle panel 144 configured on one side of the frame 141 to allow the frame 141 to be inserted and detached from the housing 110.
The method of claim 5, wherein the perforated plate 142,

A composite polymer composition to prevent corrosion is coated on the surface,

The composite polymer composition,

50 to 60 parts by weight of a filler is added and mixed to 100 parts by weight of the polymer, and the polymer is from the group consisting of a silicone resin, an epoxy resin, an acrylic resin, a mixture thereof, and a copolymer thereof. It is selected, and the filler includes a first filler having a first average particle diameter, a second filler having a second average particle diameter, and a third filler having a third average particle diameter, and the first average particle diameter value is 10 to 30 μm. It is greater than the remaining average particle diameter values, the second average particle diameter value divided by the first average particle diameter value is 0.17 to 0.26, the third average particle diameter value divided by the first average particle diameter value is 0.09 to 0.11, and the first 1 filler, 2nd filler and 3rd filler have an average value of short/long diameter of 0.6 to 0.8, and the percentage of the sum of the masses of the second fillers/the mass of the first fillers is 11 to 16, or the sum of the masses of the third fillers The percentage of the sum of the mass of 1 filler is 4.2 to 5.2, and the first filler, the second filler, and the third filler are alumina (Al2O3), boron nitride (BN), aluminum nitride (AlN), silicon nitride (Si3N4), and magnesia (MgO). ), beryllia (BeO), zinc oxide (ZnO), silicon carbide (SiC), zirconia (ZrO2), and a fine dust reduction device, characterized in that selected from the group consisting of a mixture thereof.