JPH0631201A - Electric precipitator and dust collecting electrode - Google Patents

Abstract

PURPOSE:To enhance dust collecting capacity and to certainly regenerate a dust collecting electrode. CONSTITUTION:A dust collecting electrode 9 is constituted of porous SiC having a three-dimensional reticulated structure capable of generating heat by the supply of a current. Particles not collected by a prefilter 3 are positively ionized by the positive corona discharge of an ionizer 5 and collected by porous SiC of the dust collecting electrode 9 to which negative voltage is applied. The dust collecting electrode 9 is detached from an electric precipitator to be heated to incinerate the particles collected and accumulated on the dust collecting electrode 9. By this constitution, the contact of an air stream P with porous SiC becomes complicated and dust collecting capacity can be enhanced and the dust collecting electrode 9 can be certainly regenerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic precipitator for collecting particles, oil mist and the like contained in exhaust gas and removing dust and smoke in the air. The present invention relates to an electrostatic precipitator that uses a porous silicon carbide sintered body that has good dust collecting performance and can generate heat when energized.

[0002]

2. Description of the Related Art As an electrostatic precipitator of this type, particles in exhaust gas, dust in air, etc. are ionized by a charging section equipped with a discharge electrode for generating a corona discharge and ionizing the particles. Various devices according to the structure of the charged part and the dust collecting electrode, the use for air cleaning and industrial purposes, the properties of gas and particles, etc. Is proposed.

Particularly, for air cleaning, the discharge electrode of the charging section and the dust collecting electrode are arranged in parallel with each other at an interval of several millimeters to several tens of millimeters so as to reach the dust collecting electrode in the dust collecting space. There are some that have a higher collection rate. However, in the electrostatic precipitator having such a structure, the particles collected on the collecting electrode may cause a reverse ionization phenomenon, or a re-scattering phenomenon of the collected particles may occur, so that the dust collecting performance is deteriorated. There is a problem.

Further, in various electrostatic precipitators, it is possible to collect all kinds of solid and liquid fine particles (dust, mist, fumes, etc.) at a high dust collecting rate. Also, there is a problem that the dust collecting performance is deteriorated for submicron particles of 5 μm or less. Therefore, in order to improve the dust collection performance, electrostatic packed bed dust collectors, electrostatic filtration dust collectors, and the like have been proposed.

The electrostatic packed bed dust collector is provided with a packed layer filled with insulating particles as a dust collecting electrode, and an electric field is formed in the packed layer so that particles (such as dust) are attached to and collected on the insulating particles. I have to. Further, the electrostatic filtration dust collector is composed of a fiber layer made of a dielectric as a dust collecting electrode provided with metal nets on both sides, and a high voltage is applied between the both metal nets to attract particles to the fiber layer. There is an electrostatic fiber layer dust collecting device. Further, there is an electrostatic bag filter in which the dust collecting electrode is composed of a dust collecting plate and a bag filter made of a conductive fiber, and the bag filter and the dust collecting plate collect particles.

[0006]

In the former electrostatic packed bed dust collector, however, the electric field of the packed bed effectively attaches and collects particles to the insulating particles to improve the dust collecting performance of submicron particles. Although it can be done, there is a problem that it is difficult to regenerate the insulating particles to which the particles adhere.

That is, since the insulating particles are continuously taken out and the dust is removed by the screen and are then circulated again, the dust which has not been completely removed is insulated as the circulation is repeated. There is a problem that not only the particles are deposited and deposited on the particles to make it difficult to regenerate, but also stable dust collection cannot be continued due to the deposited dust.

In the latter electrostatic filtration dust collector, in the electrostatic fiber layer dust collector, particles are attracted onto the fibers by a strong electric field formed in the vicinity of the fiber layer to collect submicron particles. Although the dust performance can be improved, there is a problem that it is difficult to regenerate the fiber layer.

That is, since the particles sucked onto the fibers penetrate into the fiber layer, it is difficult to remove the particles and it is necessary to replace them with new conductive fibers.

Further, in the electrostatic bag filter of the electrostatic filtration dust collector, the particles are removed by the dust collecting electrode and the bag filter, so that the dust collecting performance of the submicron particles can be improved. There is. Further, when the particles accumulated on the dust collecting plate are peeled off, the punching is performed. However, the re-scattering of the collected dust due to the punching can be prevented by the bag filter. However, there is a problem that it is difficult to regenerate the bag filter like the fiber layer.

That is, since the bag filter also has a fibrous shape, it is difficult to remove particles that have penetrated into the fiber layer, and it is necessary to replace it with a new conductive fiber.
An object of the present invention is to provide an electrostatic precipitator that can improve the dust collecting performance and can reliably regenerate the dust collecting electrode, and a dust collecting electrode thereof.

[0012]

In order to solve the above-mentioned problems, the invention of claim 1 is a dust collecting electrode arranged on the downstream side of the charging portion of the electrostatic precipitator, which is an energized heat generator. The gist is that it is made of a porous silicon carbide sintered body capable of

This porous silicon carbide sintered body (hereinafter simply referred to as S
Since (iC) is porous, contact with SiC is complicated and a contact area is large when a fluid such as exhaust gas passes through. Therefore, the particles ionized by the corona discharge in the charging portion collide with the electrode in the porous silicon carbide sintered body and are electrically efficiently collected by the Coulomb force.

Further, SiC can generate heat by energization and has heat resistance since it is a sintered body. Therefore, Si
C is heated to a high temperature by applying a voltage, and the particles collected in the SiC are incinerated and regenerated.

Further, according to the invention of claim 2, a charging part for applying a high voltage to generate a corona discharge, and a dust collecting electrode for electrically collecting particles ionized by the corona discharge of the charging part. In the electrostatic precipitator provided with, the dust collecting electrode is composed of a porous silicon carbide sintered body capable of energization and heat generation,
The gist of the present invention is that the dust collecting electrode is detachably arranged with respect to the apparatus body.

In this electric dust collector, when incinerating the collected particles to regenerate the dust collecting electrode, the dust collecting electrode is taken out of the main body of the apparatus and then heated by an electric furnace or the like.
Then, the dust collecting electrode is heated to a high temperature, and the particles in the dust collecting electrode are incinerated and regenerated. Then, the dust collecting electrode is attached to the original position again.

Further, in the invention of claim 3, a charging part for applying a high voltage to generate a corona discharge, and a dust collecting electrode for electrically collecting particles ionized by the corona discharge of the charging part. In the electrostatic precipitator including the above, the dust collecting electrode is formed of a porous silicon carbide sintered body capable of generating heat by electric conduction, and the dust collecting electrode is provided with an energizing electrode. To do.

In this electrostatic precipitator, when a dust collecting electrode is regenerated by incinerating the collected particles, when a voltage is applied to the current-carrying electrodes arranged in the dust collecting electrode, the dust collecting dust is collected. The pole is heated to a high temperature, and the particles are incinerated and regenerated without being taken out from the device body.

[0019]

【Example】

[First Embodiment] A first embodiment in which the present invention is embodied in an air cleaner will be described below with reference to FIGS. 1 and 2.

As shown in FIGS. 1 and 2, the air purifier D is provided with a casing 1 as a device body made of a metal square pipe, and a heat insulating material 2 made of ceramic fiber is arranged on the inner peripheral surface thereof. Has been done. Further, the most upstream side in the casing 1 (hereinafter, the front side in FIG. 1 and the left side in FIG. 2 are upstream and the opposite side is downstream) is used for capturing large particles in the air. The pre-filter 3 is provided.

The prefilter 3 is made of porous SiC formed in a block shape with the same three-dimensional mesh structure as the dust collecting electrode 9 to be described later, and its mesh roughness is 8 mesh (pore diameter: 2 to 3 mmφ). Has become.

All side surfaces of the prefilter 3 are sealed with SiC. Then, for example, when the air flow P passes through the pre-filter 3, particles having a relatively large size among the particles in the air flow P collide with the skeleton of the porous SiC and are collected.

Further, the pre-filter 3 generates heat when an AC voltage is applied from a power source (not shown), and the collected particles are incinerated. An ionizer 5 as a charging unit is arranged on the downstream side of the prefilter 3. The ionizer 5 includes a discharge electrode (hereinafter, referred to as a discharge electrode) 6 and a counter electrode 8 facing the discharge electrode 6.

The counter electrode 8 is made of an aluminum block, and a plurality of vent holes 8a are formed at positions corresponding to the discharge electrodes 6. The discharge electrode 6 is provided with a high-voltage auxiliary electrode 7. The high-voltage auxiliary electrode 7 is made of stainless steel and is formed in a square frame shape, and the same stainless steel rods 7a are attached in a grid shape in the frame. . Also, each stainless steel rod 7
A discharge electrode 6 made of stainless steel is projected toward the upstream side at the intersection of a.

The tip of this discharge electrode 6 is sharp so that the concentration of the electric field becomes large when a voltage is applied.
The counter electrode 8 is assembled such that the inner peripheral surface of the vent hole 8a and the discharge electrode 6 are separated from each other by a constant distance, and is brought into contact with the high-voltage auxiliary electrode 7.

Further, a positive voltage is applied to the discharge electrode 6 from a power source (not shown) and a negative voltage is applied to the counter electrode 8. When a certain critical voltage is exceeded, a positive corona is applied to the discharge electrode 6. An electric discharge is generated so that the particles are positively ionized.

A dust collecting electrode 9 is arranged on the downstream side of the ionizer 5. Like the prefilter 3, the dust collecting electrode 9 is made of porous SiC in a block shape (15 cm ×
15 cm × 15 cm). The coarse SiC of the dust collecting electrode 9 has a mesh of 12 mesh (pore diameter: 1.3 mmφ).

The roughness of this porous SiC is 5
-14 mesh (pore diameter: 3.9-1.1 mmφ) is desirable. When the roughness of the mesh is less than 5 mesh, for example, there is a possibility that particles in the air flow P collide with the skeleton of the porous SiC and the dust collecting performance is deteriorated. Also,
When the mesh roughness exceeds 14 meshes, the resistance of the air flow P passing through the dust collecting electrode 9 increases, and the pressure loss increases.

The main characteristics of porous SiC are:
Bulk specific gravity: 0.4 to 0.5 g / cc, porosity: 84 to 8
8%, heat resistant temperature: 1500 ° C. Furthermore, the porous SiC is doped with impurities (B, P, Bi, Sb, etc.) and has a low resistance value (specific resistance: 1.5 Ω · cm (25 ° C.)) that can generate heat upon energization.
Further, all side surfaces of the dust collecting electrode 9 are sealed with SiC. The porous SiC is manufactured by Tokai Carbon Co., Ltd., for example.

Further, a negative voltage is applied to the dust collecting electrode 9 by a power source (not shown), and the particles positively ionized by the ionizer 5 are attracted by the strong Coulomb force. It is designed to be attached and collected inside.

A handle 10 is provided on one side surface of the dust collecting electrode 9, and a door 11 (shown by a chain double-dashed line in FIG. 1) can be opened and closed on a side surface of the casing 1 corresponding to the handle 10. It is provided. Further, a pair of guide plates 12 made of an insulating material for guiding the upper and lower surfaces of the dust collecting electrode 9 are attached to the inner side surface of the casing 1.

The dust collecting electrode 9 is taken out of the apparatus by opening the door 11 and pulling it out through the handle 10. A catalyst 13 for decomposing and deodorizing ozone generated by corona discharge of the ionizer 5 is arranged downstream of the dust collecting electrode 9.

On the downstream side of the catalyst 13, a slit-shaped magnetic plate 14 for magnetizing the air flow P from which particles have been removed is arranged. Next, the operation of the air purifier D thus configured will be described.

It is assumed that a voltage is applied to the ionizer 5 and the dust collecting electrode 9 by a power source (not shown) of the air purifier D. When an air flow P containing smoke, oil mist, etc. is supplied to the pre-filter 3 by the action of a fan (not shown), oil mist particles having a relatively large particle size collide with the skeleton of porous SiC in the pre-filter 3. And collected.

Then, the particles not collected by the pre-filter 3 are positively ionized by the positive corona discharge generated at the discharge electrode 6 of the ionizer 5, and pass through the ventilation hole 8a of the counter electrode 8. It is supplied to the dust collecting electrode 9.

Since a negative voltage is applied to the dust collecting electrode 9, positively ionized smoke and oil mist particles are attached and collected in the dust collecting electrode 9 by the action of a strong Coulomb force. To be done. At this time, some of the smoke and oil mist particles may collide with the skeleton thereof due to the structure of the porous SiC, and the particles are more efficiently collected.

Next, the air flow P in which smoke and oil mist particles have been collected by the dust collecting electrode 9 is decomposed by the catalyst 13 such as ozone generated in the ionizer 5 and then by the magnetic plate 14. It is magnetized and discharged as clean air.

Next, when incinerating the collected and accumulated particles to regenerate the dust collecting electrode 9, after opening the door 10, the handle 1 is opened.
After pulling out the dust collecting electrode 9 while holding 0, the dust collecting electrode 9 is heated in an electric furnace (not shown) outside the apparatus. Then, the porous SiC is heated, the deposited particles are incinerated, and the dust collecting electrode 9
Is played.

After that, the dust collecting electrode 9 is inserted into the apparatus along the guide plates 12 and the door 10 is closed to complete the setting of the dust collecting electrode 9. In the pre-filter 3 as well, outside the apparatus, the pre-filter 3 is heated by an electric furnace or the like to incinerate and regenerate the deposited particles.

As described above, in the first embodiment, the dust collecting electrode 9 is made of porous SiC having a three-dimensional mesh structure, so that when the air flow P passes through the porous SiC, it comes into contact with the skeleton in a complicated manner. Then, there is a stirring effect of stirring the air flow P. Further, since the particles contained in the air flow P that is agitated by the agitation effect have an inertial force, when the direction of the air flow P changes due to agitation, the particles collide with the skeleton of the porous SiC in order to maintain the initial direction. There is an inertial dust removal effect that is collected by Further, there is a collision separation effect in which particles colliding with the skeleton of the porous SiC are separated and collected. Therefore, the dust collecting performance can be improved by these effects.

Further, the dust collecting electrode 9 is taken out of the apparatus and heated in an electric furnace to incinerate the particles collected and accumulated in the dust collecting electrode 9, so that the dust collecting electrode 9 is removed. It can be reliably reproduced.

Further, the dust collecting electrode 9 is detachably attached to the main body of the apparatus so that the dust collecting electrode 9 collects particles.
And the unused dust collecting electrode 9 are alternately exchanged to process the air flow P, the device can be efficiently and continuously operated.

[Second Embodiment] Next, a second embodiment will be described. The same components as those in the above-mentioned embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 3, the dust collecting electrode 9 of the second embodiment.
Electrodes 15 made of a pair of metal plates (only one side is shown) are welded to opposite side surfaces of the porous SiC.
The electrode 15 is connected to a power source (not shown), and a DC voltage is applied to the dust collecting electrode 9 via the electrode 15. Therefore, the door 10 and the guide plate 12
Is not provided.

When the collected and accumulated particles are incinerated to regenerate the dust collecting electrode 9, unlike the first embodiment, when a voltage is applied through the electrode 15 in the apparatus, porous SiC is used. Generates heat (in this case, 400 to 500
(° C), the accumulated particles are incinerated and the dust collecting electrode 9 is regenerated.

As described above, in the second embodiment, the dust collecting performance can be improved, and the dust collecting electrode 9 is made to generate heat inside the device, so that it is not necessary to take it out of the device, The dust collecting electrode 9 can be easily regenerated when the vehicle is not in operation.

The present invention is not limited to the above-mentioned embodiments, but may be modified as follows without departing from the spirit of the present invention. (1) In the above-described embodiment, the pre-filter 3 is arranged on the most upstream side in the casing 1, and the catalyst 13 and the magnetic plate 14 are provided on the downstream side of the dust collecting electrode 9. type,
Depending on the amount of ozone generated, etc.
It may be made of a material different from iC, or may be eliminated, or the catalyst 13 and the magnetic plate 14 may be eliminated. (2) In the above-described embodiment, as the air cleaner D, a positive voltage is applied to the discharge electrode 6 of the ionizer 5 and a negative voltage is applied to the counter electrode 8 to generate a positive corona discharge on the discharge electrode 6 to generate particles. Although it was made to be positively ionized, conversely, as an industrial dust collector, a negative voltage is applied to the discharge electrode 6, a positive voltage is applied to the counter electrode 8, and a negative corona discharge is generated in the discharge electrode 6, The particles may be negatively ionized. Accordingly, a positive voltage may be applied to the dust collecting electrode 9 to collect the negatively ionized particles. (3) In the above embodiment, the particles are collected without applying a negative voltage to the pre-filter 3 unlike the dust collecting electrode 9, but a positive voltage is applied to the pre-filter 3 to cause the ionizer It is also possible to collect partially negatively charged particles without going through 5. (4) In the above embodiment, the electrode 15 is made of a metal plate, but instead, for example, ceramics having a smaller specific resistance than porous SiC may be used.

[0048]

As described above in detail, according to the inventions of claims 1 and 2, the dust collecting performance can be improved and the dust collecting electrode can be reliably regenerated. Produce an effect.

According to the invention of claim 3, the dust collecting performance can be improved, and the dust collecting electrode can be easily regenerated.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing the configuration of a first embodiment.

FIG. 2 is a partial sectional view showing the inside of the same.

FIG. 3 is a schematic perspective view showing a configuration of a second embodiment.

[Explanation of symbols]

1 ... Casing (apparatus main body), 5 ... Ionizer (charging part), 6 ... Discharge electrode, 8 ... Counter electrode, 9 ... Dust collecting electrode, 15 ...
Electrode, D ... Air purifier

Claims (3)

[Claims] 1. A dust collecting electrode (9) disposed on the downstream side of a charging section (5) of an electrostatic precipitator, which is made of a porous silicon carbide sintered body capable of generating heat by energization. A dust collecting electrode. 2. A charging part (5) for applying a high voltage to generate a corona discharge, and a dust collecting electrode (9) for electrically collecting particles ionized by the corona discharge of the charging part (5). )
In the electrostatic precipitator including the above, the dust collecting electrode (9) is made of a porous silicon carbide sintered body capable of generating heat by energization.
The dust collector (9) is detachably attached to the device body (1). 3. A charging part (5) for applying a high voltage to generate a corona discharge, and a dust collecting electrode (9) for electrically collecting particles ionized by the corona discharge of the charging part (5). )
In the electrostatic precipitator including the above, the dust collecting electrode (9) is made of a porous silicon carbide sintered body capable of generating heat by energization.
An electric dust collector is also provided with an energizing electrode (15) on the dust collecting electrode (9).