JP2003305380A - Electric precipitator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the consumption of a cleaning liquid when cleaning an electric precipitator. <P>SOLUTION: The wet one-stage type electric precipitator 9 has a discharge electrode 4 for negative charging dust particles contained in a soot-containing dust gas Gs and a dust collection electrode 3 for collecting the charged soot- containing dust gas Gs. The dust collection electrode 3 is arranged parallel to the flow direction of the soot-containing dust gas Gs and the discharge electrode 4 is provided in opposed relation to the dust collection electrode 3. Further, a nozzle 12 for spraying the cleaning liquid in order to clean the dust collection electrode 3 is provided to the upper part in a casing 1. A hydrophilic substance and a conductive substance are supported at least on the surface of a counter electrode 40 of the above charging part. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic precipitator, and more specifically, it facilitates the removal of contaminants adhering to electrodes to reduce the amount of cleaning liquid used when cleaning the electrostatic precipitator. The present invention relates to an electric dust collector.

[0002]

2. Description of the Related Art There is an electrostatic precipitator which utilizes electrostatic force to remove particulate matter such as fine solid dust and liquid particles suspended in gas or air. Such an electrostatic precipitator has been widely used from purification of exhaust gas in various industries to purification of indoor air in the home, and has been effective.

An electrostatic precipitator for treating gas or air having a relatively low concentration of particulate matter of several mg / m ³ or less is
Generally, there are many things with the following configurations. That is, it has a configuration in which it is divided into a charging unit provided on the upstream side for mainly charging the particulate matter and a dust collecting section provided on the downstream side for collecting the particulate matter. The charging section is composed of a counter electrode and a discharge electrode, and charges the dust with a negative charge by corona discharge generated from the discharge electrode. Then, in the dust collecting portion arranged downstream of the charging portion, the dust is collected by the dust collecting electrode having an electric field between the dust collecting portion discharge electrode to which a high voltage is applied. Such a two-stage type electrostatic precipitator is mainly used for air purification in a room or in a road tunnel.

On the other hand, most of the electrostatic precipitators for treating gas or air having a high particulate matter concentration of several mg / m ³ or more generally have the following constitution. That is, in order to charge the particulate matter and collect dust with the same electric field, a discharge electrode provided parallel to the flow direction of the dust-containing gas and a discharge electrode provided opposite to the discharge electrode. It is a one-stage type electrostatic precipitator having a dust pole. Primarily it is used for general industrial dust removal.

[0005]

However, in the two-stage type electrostatic precipitator, since the charging portion is arranged at the inlet of the gas containing dust, it is opposed to the discharge electrode which causes corona discharge. Soot and dust are likely to accumulate on the counter electrodes arranged. When soot and dust are accumulated here, the discharge efficiency is reduced, and as a result, the soot and dust charging efficiency is also reduced. As a result, the dust collection efficiency of the dust collecting electrode disposed downstream of the charging unit is reduced, and the performance of the electrostatic precipitator is reduced. Then, the adhered dust is washed with water or a cleaning liquid in which a cleaning agent or the like is added, but it is difficult to remove the dust once adhered. Therefore, a large amount of cleaning liquid is required for this cleaning, which is wasteful. Particularly in road tunnels, the gas containing dust contains a large amount of carbon components and oil. Therefore, in the electrostatic precipitator used here, dust is likely to adhere to the counter electrode and the dust collecting electrode. The dust once attached is more difficult to drop as compared with an ordinary electrostatic precipitator, and a larger amount of cleaning liquid is required for cleaning.

Further, among the one-stage type electrostatic precipitators, in a wet type electrostatic precipitator for spraying a cleaning liquid such as water onto at least the dust collecting electrode to remove the dust collected on the dust collecting electrode, It is very difficult to uniformly form a liquid film on the entire surface of the dust collecting electrode, and a large amount of cleaning liquid is required. Further, when the object to be collected is a substance such as corrosive sulfuric acid mist, there is a problem that corrosion progresses on the surface of the dust collecting electrode on which the liquid film of the cleaning liquid is not formed.

Therefore, the present invention has been made in view of the above, and reduces the amount of the cleaning liquid used when cleaning the electrostatic precipitator, and facilitates the removal of the contaminant components adhering to the electrodes. It is an object of the present invention to provide an electrostatic precipitator capable of achieving at least one of reduction of dust collection performance as much as possible even during long-term use and reduction of electrode corrosion as little as possible.

[0008]

In order to achieve the above-mentioned object, a two-stage type electrostatic precipitator according to a first aspect of the present invention is a charging unit installed parallel to the flow direction of soot dust gas. The soot-containing dust having a counter electrode and a charging discharge electrode provided to face the charging unit counter electrode, and causing corona discharge between the charging discharge electrode and the charging unit counter electrode. A charging unit for applying a negative electric charge to the dust and dust contained in the gas to charge the dust and dust, an electrode for collecting dust that is installed in parallel with the flow direction of the dust and dust gas, and facing the dust collecting electrode. A dust collecting discharge electrode for applying a high voltage is provided, and a dust collecting portion that collects dust particles negatively charged by the charging portion on the dust collecting electrode, and at least the above by spraying a cleaning liquid. Cleaning liquid spraying means for cleaning the charging unit counter electrode, The surface of the part opposite electrode, characterized in that by supporting a hydrophilic substance and a conductive substance.

This two-stage type electrostatic precipitator comprises a charging section for negatively charging the dust particles contained in the dust-containing gas and a dust collecting section for collecting the dust particles by a dust collecting electrode. And a hydrophilic substance and a conductive substance are carried on at least the surface of the charging unit counter electrode of the charging unit.
Therefore, when cleaning the charging unit counter electrode, a uniform cleaning liquid film is formed on the surface of the charging unit counter electrode. And
Since the cleaning liquid enters between the dirt and the surface of the hydrophilic counter electrode of the charging unit, dust particles and other contaminants adhering to the counter electrode of the charging unit can be easily washed off. By these actions, the dust particles can be efficiently removed and the amount of the cleaning liquid can be reduced.

Further, the uniform cleaning liquid film formed on the surface of the counter electrode or the like can reduce the adhesion of dust and other contaminants to the surface of the charging unit counter electrode. By this action, it is possible to suppress the decrease in discharge current due to the adhesion of dirt to the counter electrode of the charging unit and the decrease in dust collection efficiency, so that high dust collection performance can be exhibited for a long period of time.

It should be noted that not only the charging unit counter electrode of the charging unit, but also the charging discharge electrode of the charging unit, the dust collecting electrode of the dust collecting unit, or the dust collecting discharge electrode of the dust collecting unit is made of a hydrophilic substance. A conductive substance may be supported (the same applies hereinafter). By doing so, the above-described actions and effects are exerted also on these electrodes, so that a two-stage type electrostatic precipitator having higher performance can be obtained (the same applies hereinafter).

According to a second aspect of the present invention, there is provided a one-stage type electrostatic precipitator in which a discharge electrode is provided in parallel with a flow direction of the dust-containing gas and a dust collector is provided opposite to the discharge electrode. An electrode, which causes corona discharge between the discharge electrode and the dust collecting electrode to simultaneously charge dust and collect dust, and further spray a cleaning liquid to at least the dust collecting electrode. A cleaning liquid spraying means for cleaning the above is provided, and a hydrophilic substance and a conductive substance are carried on at least the surface of the dust collecting electrode.

This one-stage type electrostatic precipitator exhibits the action and effect of the above invention in the intermittent or continuous spraying of the cleaning liquid. Furthermore, since the uniform film of the cleaning liquid is formed on the electrode surface by the hydrophilic substance carried on the electrode surface, the progress of corrosion of the electrode can be reduced when the object to be collected is corrosive.

Here, the soot-containing dust gas is a gas containing soot dust, and a gas containing fine particles of solid or liquid (the same applies hereinafter). For example, it is air in a road tunnel, exhaust gas from a gas turbine or gas engine or a boiler, or exhaust gas from a combustion furnace such as an incinerator (the same applies hereinafter). The conductive substance is, for example, a carbon-based substance such as carbon black or graphite, a metal oxide such as titanium oxide or tin oxide, a metal powder such as copper or nickel, etc. It is possible to use a material having an appropriate electric conductivity.

Further, as the hydrophilic substance, a silicate compound can be used as in the present invention according to claim 3. Since this compound has high weather resistance and durability,
This is preferable because it can reduce the maintenance and inspection work. As such a compound, for example, a silanol group (SiOH) produced by hydrolyzing an alkoxysilyl group (SiOR) of a silane-based compound or a low-molecular alkoxysiloxane oligomer is added into a coating material, and the surface is hydrolyzed. There is a hydroxysilyl group generated by decomposition.

Further, as in the present invention according to claim 4,
A superhydrophilic substance may be used as the hydrophilic substance. Since the contact angle with water of the superhydrophilic substance is 10 degrees or less,
By supporting such a substance on the surface of the discharge electrode or the like, the above-described action of the cleaning liquid entering between the dirt and the hydrophilic charging electrode surface can be further promoted. By this action, it is possible to more easily wash away the contaminants adhering to the surface of the discharge electrode or the like, and it is possible to obtain the effect of further reducing the trouble of maintenance and inspection.

Further, an electric dust collector for a road tunnel according to a fifth aspect is the two-stage type electric dust collector according to any one of the first, third or fourth aspects, in which soot dust gas is contained. As a feature, air in a road tunnel through which a vehicle travels is supplied to remove dust and dirt contained in the air.

A large amount of exhaust gas emitted from a vehicle exists in a road tunnel through which the vehicle passes. In addition, such exhaust gas contains a large amount of pollutants such as carbon and oil. Therefore, if such a contaminant adheres to the charging unit counter electrode provided in the charging unit of the electrostatic precipitator, it cannot be sufficiently washed off by ordinary cleaning. Then, such a pollutant shortens the period during which the dust collection performance can be sufficiently exhibited, and it takes time and effort to perform maintenance and inspection for recovering the dust collection performance.

In the electric dust collector for this road tunnel,
The two-stage type electric dust collector is used to remove the dust contained in the air in the road tunnel. For this reason, it is difficult for contaminants such as carbon and oil components to adhere to the charging unit counter electrode provided in the charging unit, and even if such contaminants are present, the action of the hydrophilic substance carried on the surface causes It can be easily washed off by the cleaning liquid spraying means provided in the two-stage type electrostatic precipitator. As a result, the dust collection performance can be exhibited for a long period of time, and the labor for maintenance and inspection can be reduced. Furthermore, since the dust can be stably charged by the conductive substance carried by the charging unit counter electrode, stable dust collecting performance can be exhibited. Further, since the conductive material also increases the discharge efficiency, the dust collection efficiency can be increased.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to the drawings. The present invention is not limited to this embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

(Embodiment 1) FIG. 1 is an explanatory view showing a two-stage type electrostatic precipitator according to Embodiment 1 of the present invention. 2 is a view taken along the line AA of FIG. This two-stage type electrostatic precipitator is characterized in that at least the charging portion counter electrode of the charging portion is subjected to a hydrophilic treatment and a conductive treatment. As shown in FIG. 1, this two-stage type electrostatic precipitator 10
Is provided with a dust collecting unit 50 having a charging unit 52 and a dust collecting unit 54 inside the casing 20. And
Gas containing soot and dust (hereinafter referred to as soot and dust gas) Gs
Is introduced from the gas inlet 21i and the dust collecting unit 50
While passing through the charging unit 52 and the dust collecting unit 54, the dust in the dust gas Gs is collected. The dust-containing dust gas Gs after dust collection is discharged from the gas outlet 21e.

As shown in FIG. 2, a cleaning nozzle 2 for spraying a cleaning liquid for cleaning the dust collecting unit 50 is provided above the casing 20 in the vertical direction U, upstream L and downstream T.
2 is provided. This is preferable because the cleaning ability can be increased and the dirt on the dust collecting unit 50 can be removed more completely. The number of the cleaning nozzles 22 can be appropriately selected according to the size of the dust collecting unit 50. Further, the cleaning nozzle 22 is provided with a pipe 24 for sending a cleaning liquid to the cleaning nozzle 22.
The cleaning liquid stored in the cleaning liquid tank 28 by 6 is supplied to the cleaning nozzle 22. Here, water is used as the cleaning liquid, but a detergent such as a surfactant or alcohol may be appropriately added to the water in order to improve the cleaning ability.

It should be noted that U above the casing 20 in the vertical direction,
When the cleaning nozzles 22 cannot be provided on all of the upstream side L and the downstream side T, at least the casing 20
It is preferable to provide the cleaning nozzle 22 on the upper side U in the vertical direction. By doing so, the entire dust collection unit 50 can be washed using gravity, so that the casing 2
It is easier to remove dirt from the dust collecting unit 50 than when the cleaning nozzle 22 is provided on at least one of the upstream side L and the downstream side T of 0.

From the cleaning nozzle 22 to the dust collecting unit 5
By spraying the cleaning liquid on 0, the dust collecting unit 50 to which the dust particles in the dust-containing gas Gs adhere is washed. In addition, as shown in FIG. 2, this electrostatic precipitator 1
The casing 20 of 0 has a drain hole 20d at the bottom, and the cleaning waste liquid after cleaning the dust collecting unit 50 is discharged from the drain hole 20d. Then, the cleaning waste liquid is taken out of the two-stage type electrostatic precipitator 10 and purified by a purification facility (not shown) equipped with a filtering device.

Next, the dust collecting unit 50 of the two-stage type electrostatic precipitator 10 according to the first embodiment of the present invention will be described. FIG. 3 is a perspective view showing a dust collecting part provided in the two-stage type electrostatic precipitator according to the first embodiment. Figure 3
As shown in (a), the charging unit 52 and the dust collecting unit 54 provided in the dust collecting unit 50 are configured separately.

In the charging section 52, the charging section discharge electrodes 30 and the charging section counter electrodes 40 are arranged alternately and in parallel. Here, the charging part discharge electrode 30 is a linear electrode made of a tungsten wire, and the charging part counter electrode 40 is a plate-like electrode made of a stainless plate. A high voltage power supply 60 is connected to the charging section discharge electrode 30 and the charging section counter electrode 40, and a high voltage is applied by this. Here, the negative electrode of the high voltage power supply 60 is connected to the charging unit discharge electrode 30.

In the dust collecting portion 54, the dust collecting portion discharging electrode 31 which is a plate-like discharging electrode made of a stainless steel plate and the plate-like dust collecting portion collecting electrode 41 are arranged alternately and in parallel. . The dust collecting part dust collecting electrode 41 is also a plate-shaped electrode made of a stainless plate. The negative electrode of the high voltage power supply 60 is connected to the dust collecting part discharge electrode 31, and a high voltage is applied.

As shown in FIG. 3B, the charging portion discharge electrode 30 and the dust collecting portion discharge electrode 31, which are discharge electrodes in the charging portion 52 and the dust collecting portion 54, and the collecting portions in the charging portion 52 and the dust collecting portion 54. A mixture C of a hydrophilic substance and a conductive substance is carried on the charging unit counter electrode 40 and the dust collecting unit dust collecting electrode 41, which are dust electrodes. This is for the following reason. That is, when a hydrophilic substance is supported on the discharge electrode and the dust collecting electrode to make these surfaces hydrophilic, when dirt adheres to the surface, water enters between the dirt and the surface to prevent the dirt. A so-called rolling-up mechanism works by floating and letting it flow away. This is because even if the dust particles R adhere to the dust collecting electrode or the discharge electrode, stains can be easily removed by water or other cleaning liquid, and the amount of cleaning liquid used can be small.

In this example, the charging portion discharge electrode 3
0, the charging unit counter electrode 40, the dust collecting unit discharge electrode 31, and the dust collecting unit dust collecting electrode 41 all carry a hydrophilic substance and a conductive substance, but at least the charging unit counter electrode 40 carries them. It is good to do so. This is because the dust is most likely to be accumulated in the charging unit facing electrode 40, and if the dust is accumulated in this part, the discharge current is reduced and the charging efficiency of the dust is reduced, so that the dust is disposed downstream of the charging unit 52. This is because the dust collecting efficiency of the dust collecting portion 54 that is being used is reduced. Therefore, by reducing the accumulation of dust in the charging unit facing electrode 40, it is possible to suppress the reduction of the dust collection efficiency in the case of the entire two-stage electric dust collector 10. Of course, a hydrophilic substance and a conductive substance may be supported on the electrodes other than the above, and in that case, it is possible to further suppress the deterioration of the dust collection efficiency of the two-stage type electrostatic precipitator 10 as a whole. ,preferable.

A silicate compound can be used as a hydrophilic substance, which can be added to a coating material and applied to a dust collecting electrode or the like to make the surface of the dust collecting electrode or the like hydrophilic. They are,
Since it has high weather resistance and durability, it is preferable because it can reduce the maintenance and inspection work. For example, a silanol group (SiOH) produced by hydrolyzing an alkoxysilyl group (SiOR) of a silane-based compound, or a hydroxysilyl group formed by adding a low-molecular alkoxysiloxane oligomer into a coating and hydrolyzing it on the surface Etc. can be used as the hydrophilic substance.

In addition to the above-mentioned hydrophilic substance, a titania photocatalyst or a composite of titanium oxide excited by ultraviolet rays and silica may be used as a hydrophilic substance. As titania, either anatase or rutile can be used. Such a hydrophilic substance has a contact angle with water of 10 degrees or less, and is so-called superhydrophilic substance. Therefore, by supporting such a substance on the surface of the dust collecting electrode or the like, the rolling-up mechanism can be further promoted. By this action, contaminants adhering to the surface of the dust collecting electrode and the like can be washed off more easily, and the labor of maintenance and inspection can be further reduced.

Various powders can be used as the conductive material depending on the degree of electric conductivity. For example, carbon-based materials such as carbon black and graphite, metal oxides such as titanium oxide and tin oxide, and copper. Metal powders such as nickel and nickel can be used. From these, one having an appropriate electric conductivity is selected according to the specifications of the two-stage type electrostatic precipitator 10. And, if it is desired to have particularly high electrical conductivity, silver powder can be used, but the manufacturing cost becomes high. In the present invention, copper or aluminum powder,
Alternatively, it is preferable to use carbon black because the production cost can be kept relatively low while exhibiting the required conductive performance. Further, it is preferable to use a carbon-based material because electrolytic corrosion can be reduced, and thus maintenance and inspection work can be reduced.

The hydrophilic substance and the conductive substance are mixed with a binder to prepare a mixed coating material, and the mixed coating material is applied to the surface of the dust collecting electrode or the like by a coating means such as a spray, whereby the surface of the dust collecting electrode or the like is coated. It is possible to support a hydrophilic substance and a conductive substance. As the binder, for example, resins such as acrylic, vinyl, epoxy, alkyd, fluorine, silicon, urethane can be used. In addition,
As the mixed paint, there are water-based ones and oil-based ones using a solvent, but since it is necessary to wash the dust collecting electrode etc. with a cleaning liquid such as water, use an oil-based mixed paint. Is preferred.

Here, the principle of dust collection of the two-stage type electric dust collector 10 will be described. FIG. 4 is an explanatory diagram showing a dust collecting principle of the two-stage type electrostatic precipitator according to the first embodiment. As shown in FIG. 4, the dust-containing dust gas Gs flowing from the upstream side L is first introduced into the charging section 52. And
Negative ions I generated by corona discharge generated between the charging unit discharge electrode 30 and the charging unit counter electrode 40,
The dust particles R contained in the dust-containing gas Gs are combined and the dust particles R are negatively charged.

A part of the negatively charged dust particles R is attracted to the charging portion counter electrode 40, which is the ground electrode, while the dust-containing dust gas Gs flows toward the downstream side, so that the charging portion counter electrode 40 is charged. Adheres to the surface. Then, the remaining dust particles R are attracted to the dust collecting electrode 41, which is an earth electrode, while the dust-containing gas Gs flows through the dust collecting portion 54, and adhere to the surface of the dust collecting electrode 41. To do. In this way, since the dust particles R contained in the dust-containing gas Gs are removed, clean gas flows out from the downstream side T of the dust collecting portion 54. When the dust particles R adhering to the dust collecting portion dust collecting electrode 41, the charging portion facing electrode 40, and the like reach a certain amount, the cleaning liquid is sprayed from the cleaning nozzle 22 (see FIG. 2) after the application of the high voltage is stopped. Then, the dust particles R are washed off from the dust collecting electrode 41 and the like.

Two-stage type electrostatic precipitator 10 according to the present invention
Then, at least the charging section counter electrode 40, which is the charging section counter electrode of the charging section 52, carries a hydrophilic substance and a conductive substance. Therefore, at the time of cleaning, a uniform film of the cleaning liquid is formed on at least the surface of the charging unit counter electrode 40.
Then, by the rolling-up mechanism, dust particles and other contaminants attached to the charging unit counter electrode 40 can be easily washed off. In addition, the charging unit counter electrode 4
The uniform film of the cleaning liquid formed on the surface of No. 0 can reduce the adhesion of contaminants to the surface of the dust collecting electrode and the like, and the cleaning liquid is less likely to be a water drop, so that the dust collecting electrode etc. dries in a short time. By these actions, the dust particles can be efficiently removed and the amount of the cleaning liquid can be reduced. Also,
Since it is possible to suppress a decrease in discharge current due to dirt attached to the discharge electrode and the dust collecting electrode and a decrease in dust collecting efficiency, it is possible to exhibit high dust collecting performance for a long period of time. As a result, it is possible to prevent the dust collection efficiency of the two-stage electric dust collector 10 as a whole from decreasing.

In particular, when the discharge current is large, more dust and contaminants adhere to the charging unit counter electrode 40, and in such a case, the effect of the present invention is further enhanced. Further, as described above, when the hydrophilic substance and the conductive substance are carried on the electrodes other than the charging unit counter electrode 40, the dust collection efficiency of the two-stage type electrostatic precipitator 10 as a whole is further improved. The decrease can be suppressed.

(Second Embodiment) FIG. 5 is an explanatory view showing a wet one-stage type electrostatic precipitator according to a second embodiment of the present invention. This wet one-stage type electrostatic precipitator 9 has a structure similar to that of the two-stage type electrostatic precipitator 10 according to the first embodiment, but the dust collecting unit 50 includes the discharge electrode 4 and the dust collecting electrode 3. The difference is the configuration. Further, this wet one-stage type electrostatic precipitator 9 is characterized in that at least the surface of the dust collecting electrode 3 is subjected to a hydrophilic treatment and a conductive treatment.

As shown in FIGS. 5A and 5B, the wet one-stage type electrostatic precipitator 9 includes a discharge electrode 4 attached to a discharge electrode support frame 5 inside a casing 1 and a dust collection electrode. Three
And are arranged alternately. And soot dust gas Gs
While being introduced from the gas inlet 2i and passing between the discharge electrode 4 and the dust collecting electrode 3, the dust in the soot containing dust gas Gs is collected. The dust-containing dust gas Gs after the dust collection is discharged from the gas outlet 2e.

As shown in FIG. 5A, a cleaning nozzle 12 for spraying a cleaning liquid for cleaning the dust collecting electrode 3 and the discharge electrode 4 is provided above the casing 1 in the vertical direction. The number of the cleaning nozzles 12 can be appropriately selected according to the size and number of the dust collecting electrodes 3 and the discharge electrodes 4. A pipe 14 for sending a cleaning liquid such as water is attached to the cleaning nozzle 12, and the cleaning liquid stored in the cleaning liquid tank 18 is supplied to the cleaning nozzle 12 by a pump 16. Here, water is used as the cleaning liquid, but in order to neutralize the strongly acidic soot-containing dust gas Gs, an alkaline liquid such as sodium hydroxide may be appropriately added to the water. Good.

By spraying the cleaning liquid from the cleaning nozzle 12 onto the dust collecting electrode 3, a uniform liquid film of the cleaning liquid is formed on the surface of the dust collecting electrode 3 which has been subjected to the hydrophilic treatment, and the dust collecting electrode 3 is formed. Make sure to wash away any dust that has been attracted. Further, a drain hole (not shown) is provided at the bottom of the casing 1 of the wet type one-stage type electrostatic precipitator 9, and the cleaning waste liquid after cleaning the dust collecting electrode 3 is discharged from the drain hole. It Then, the cleaning waste liquid is discharged to the outside of the wet one-stage type electrostatic precipitator 9.

Further, in the wet one-stage type electrostatic precipitator 9 according to the second embodiment, the dust collecting performance can be improved as compared with the conventional one. As a result, more dust particles adhere to the dust collecting electrode 3 than in the conventional case. Here, in the electrostatic precipitator according to the second embodiment, at least the dust collecting electrode 3 carries a hydrophilic substance and a conductive substance. Therefore, during cleaning, a uniform film of the cleaning liquid is formed on the surface of the dust collecting electrode 3. Then, the rolling-up mechanism can easily wash away dust particles and other contaminants attached to them. Further, the uniform film of the cleaning liquid formed on the surface of the dust collecting electrode 3 can reduce the adhesion of contaminants to the surface of the dust collecting electrode 3.

The discharge electrode 4 may also carry a hydrophilic substance and a conductive substance. By doing so, it is possible to suppress a decrease in the discharge current due to the adhesion of dirt to these electrodes and a decrease in the dust collection efficiency, so that a higher dust collection performance can be exhibited for a long period of time.

(Embodiment 3) FIG. 6 is an explanatory view showing an example in which the two-stage type electrostatic precipitator according to the present invention is applied to a dust collection system for a road tunnel. This road tunnel dust collecting system 100 is characterized in that the two-stage electric dust collecting device 11 according to the present invention is installed as a road tunnel electric dust collecting device.

In FIG. 6, the air in the road tunnel 120 contains a large amount of exhaust gas discharged from the vehicle 122. The exhaust gas contains a large amount of carbon, oil and the like. Hereinafter, the dust gas Gs containing air in the road tunnel 120 is used.

The bypass tunnel 124 is provided adjacent to the road tunnel 120, and serves as an air passage 126 for bypassing the soot dust gas Gs. In this bypass tunnel 124, the two-stage type electrostatic precipitator 11 according to the present invention is installed on the inflow side of the dust-containing dust gas Gs. The two-stage type electrostatic precipitator 11 is a device for collecting soot dust particles from the soot dust gas Gs by using static electricity, and the structure and operation principle are as described above.

Here, when used as an electrostatic precipitator for a road tunnel, at least the charging unit opposing electrode 40 (see FIG. 4) in the charging unit 52 should carry a hydrophilic substance and a conductive substance. Preferably. this is,
The dust-containing dust gas Gs having the highest concentration flows into the charging portion 52, and a large number of dust particles adhere due to corona discharge from the charging portion discharge electrode 30 toward the charging portion counter electrode 40. Further, since the soot-containing dust gas Gs containing a large amount of carbon and oil first passes through the charging section 52, most of these adhere to this portion. Therefore, the charging unit counter electrode 40 is most contaminated.

On the downstream side of the two-stage type electrostatic precipitator 11,
An auxiliary equipment room 128 and an electric room 130 are provided. The blower 132 is for allowing the soot dust gas Gs to flow from the inflow side to the outflow side in the bypass tunnel 124. By this blower 132, the bypass tunnel 124
From the soot-containing dust gas Gs flowing in from the inflow side, the soot-dust particles are removed by the two-stage type electrostatic precipitator 11. Then, the clean air from which the dust has been removed is flown to the outflow side and then returned to the inside of the road tunnel 120.

Since soot dust air in a road tunnel contains a large amount of automobile exhaust gas, it also contains a large amount of carbon components and oil components. Therefore, they are easily attached to the discharge electrode or the dust collecting electrode, and once attached, they are difficult to remove. The dust collecting system 100 for a road tunnel carries a hydrophilic substance and a conductive substance on at least the charging unit counter electrode 40 (see FIG. 4). Therefore, the uniform film of the cleaning liquid formed on the surface of the charging unit facing electrode 40 can reduce the adhesion of the carbon component, the oil, and the like to the surface of the dust collecting electrode or the like. Further, during cleaning of the dust collection unit 50 (see FIG. 4), a uniform cleaning liquid film is formed on the surface of the charging unit opposing electrode 40. Can also be easily washed off. Further, since the contaminants on the charging unit counter electrode 40 can be easily washed off, the amount of cleaning liquid can be reduced,
It is economical.

As described above, dirt is less likely to adhere to the charging unit counter electrode, and the adhered dirt can be easily washed off. Therefore, the labor required for maintenance and inspection of the two-stage type electrostatic precipitator 11 can be reduced. . Generally, since the electric dust collector for road tunnels cannot be frequently maintained and inspected, it is preferable to reduce this labor. Furthermore, since the amount of cleaning liquid used is small, the number of replenishments can be reduced and frequent maintenance and
It is preferable for an electric dust collector for road tunnels that cannot be inspected.

Further, since it becomes difficult for dirt to adhere to the counter electrode 40 of the charging section, the decrease in discharge current can be suppressed. As a result, a decrease in dust collection efficiency can be suppressed, and high dust collection performance can be exhibited for a long period of time. This is very effective in an electric dust collector for road tunnels that cannot be frequently maintained and inspected. Note that the charging part discharge electrode 30, the dust collecting part discharge electrode 31, or the dust collecting part dust collecting electrode 41 (see FIG. 4) may also carry a hydrophilic substance and a conductive substance.

[0052]

As described above, in the two-stage type electrostatic precipitator according to the present invention (claim 1), this dust is provided by the charging portion for charging the dust particles to a negative charge and the dust collecting electrode. A dust collecting portion for collecting dust particles is provided, and a hydrophilic substance and a conductive substance are carried on at least the surface of the charging portion counter electrode of the charging portion. For this reason, when cleaning the charging unit counter electrode, the cleaning liquid enters between the dirt and the hydrophilic charging unit counter electrode surface, so dust particles and other contaminants attached to the charging unit counter electrode can be easily removed. Can be washed off. As a result, the dust particles can be removed efficiently and the amount of the cleaning liquid can be reduced.

Further, in the wet one-stage type electrostatic precipitator according to the present invention (claim 2), at least the surface of the dust collecting electrode is made to carry a hydrophilic substance and a conductive substance.
Therefore, when the cleaning liquid is sprayed, the liquid film can be uniformly formed on the entire surface of the dust collecting electrode. by this,
The dust particles can be efficiently removed, and the progress of corrosion of the electrode can be reduced even for a corrosive gas to be collected such as sulfuric acid mist.

Further, as in the electrostatic precipitator according to the next invention (Claim 3), if a silicate compound having excellent weather resistance and durability is used as the hydrophilic substance, maintenance and inspection can be done easily. This is preferable because it can be reduced.

Further, as in the electrostatic precipitator according to the next invention (Claim 4), when a superhydrophilic substance is used as the hydrophilic substance, the above-mentioned dirt and the surface of the hydrophilic dust collecting electrode are separated. It is possible to further promote the action of the cleaning liquid entering the. As a result, the contaminants adhering to the surface of the dust collecting electrode or the like can be washed off more easily, and the labor of maintenance and inspection can be further reduced.

Further, in the electric dust collector for the road tunnel according to the present invention (claim 5), the dust collector contained in the air in the road tunnel is removed by the electric dust collector. Therefore, it is possible to easily wash off contaminants such as carbon and oil components adhering to the counter electrode of the charging unit, so that maintenance and inspection work can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a two-stage type electrostatic precipitator according to Embodiment 1 of the present invention.

FIG. 2 is a view on arrow AA of FIG.

FIG. 3 is a perspective view showing a dust collecting portion provided in the two-stage type electrostatic precipitator according to the first embodiment.

FIG. 4 is an explanatory diagram showing a dust collecting principle of the two-stage type electrostatic precipitator according to the first embodiment.

FIG. 5 is an explanatory view showing a wet one-stage type electrostatic precipitator according to Embodiment 2 of the present invention.

FIG. 6 is an explanatory view showing an example in which the two-stage electric dust collector according to the present invention is applied to a dust collection system for road tunnels.

[Explanation of symbols]

1, 20 casing 3 Dust collecting electrode 4 discharge electrodes 5 Discharge electrode support frame 9 Wet one-stage type electrostatic precipitator 10, 11 two-stage type electrostatic precipitator 30 Charging part discharge electrode 31 Dust collector discharge electrode 40 Electrode facing charging unit 41 Dust collection electrode 50 Dust collection unit 52 Charging section 54 Dust collector 60 high voltage power supply 100 Dust collection system for road tunnel 120 road tunnel 122 vehicle 124 Bypass tunnel 126 wind path 128 auxiliary equipment room 130 Electric room 132 blower

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B03C 3/47 B03C 3/47 3/60 3/60 E21F 5/20 E21F 5/20 F24F 1/00 F24F 1/00 371B F term (reference) 3L051 BC01 4D054 AA07 BA02 BB05 BC03 BC21 BC25 DA06 DA15

Claims (5)

[Claims] 1. A charging part counter electrode provided parallel to the flow direction of the dust-containing dust gas, and a charging discharge electrode provided so as to face the charging part counter electrode. A charging unit that applies a negative electric charge to the dust contained in the dust-containing gas by causing a corona discharge between the electrode and the opposite electrode to the charging unit, and the flow direction of the dust-containing dust gas. A dust collecting electrode that is installed in parallel with the dust collecting electrode and a dust collecting discharge electrode that is provided facing the dust collecting electrode and applies a high voltage. The dust is negatively charged by the charging unit. And a cleaning liquid spraying unit that sprays a cleaning liquid to clean at least the charging unit counter electrode, and at least the surface of the charging unit counter electrode has a hydrophilic substance. Two-stage type characterized by carrying a conductive material Electric dust collector. 2. A discharge electrode provided parallel to the flow direction of the soot-containing dust gas, and a dust collecting electrode provided facing the discharge electrode, wherein the discharge electrode and the dust collecting electrode are provided. Corona discharge is generated between the electrodes to simultaneously charge dust and collect dust, and further comprises a cleaning liquid spraying unit for spraying a cleaning liquid to clean at least the dust collecting electrode, and at least the dust collecting electrode. A wet one-stage type electrostatic precipitator characterized in that a hydrophilic substance and a conductive substance are carried on the surface of the. 3. The electrostatic precipitator according to claim 1 or 2, wherein the hydrophilic substance is a silicate compound. 4. The electrostatic precipitator according to claim 1 or 2, wherein the hydrophilic substance is a superhydrophilic substance. 5. The two-stage electric dust collector according to claim 1, 3 or 4 is supplied with air in a road tunnel through which a vehicle passes as soot dust gas, An electrostatic precipitator for a road tunnel, characterized by removing dust contained in the air.