JPH0376984B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic precipitator, and more particularly to an electrostatic precipitator suitable for collecting high resistance dust and flammable mist.

An electrostatic precipitator generates a corona discharge between a discharge part and a dust collection part to form a charged band, and the dust to be collected passes through this charged band and is charged. Dust is collected by suction into the dust collecting section.

FIG. 1 is a plan view showing an example of an electrostatic precipitator commonly used in the past. The discharge part is composed of dust collecting electrodes 1a and 1b, and the discharge part includes a flat plate 2 extending between the dust collecting electrodes 1a and 1b, and fasteners 3a and 3a on the gas inflow side and gas outflow side of this flat plate 2, respectively. A discharge electrode 5 is constituted by the needle-shaped pieces 4a and 4b fixed by the needle 3b. The needle-like pieces 4a are planted at predetermined pitches along the edge of the flat plate 2 on the gas inflow side, and their tips extend toward the gas inflow side. Further, the needle-like pieces 4b are planted at predetermined pitches along the edge of the flat plate 2 on the gas outflow side, and their tips extend toward the gas outflow side.

In the electrostatic precipitator configured as described above, when a high voltage is applied between the dust collecting electrodes 1a, 1b and the discharge electrode 5 so that the discharge electrode 5 becomes a negative electrode, the needle-like pieces 4
Corona discharge is generated from the tip of a toward the dust collection electrodes 1a and 1b as shown by the dotted line. On the contrary,
When gas containing dust flows as shown by the arrow, most of the dust passing through the corona discharge area becomes negatively charged. Therefore, a charged band is formed in the area where this corona discharge occurs, and the dust charged in this charged band is distributed between the dust collecting electrodes 1a and 1b and the discharge electrode 5. The dust is attracted by the generated high electric field and collected by the dust collecting electrodes 1a and 1b. In addition, part of the oppositely charged dust that was not charged to the negative electrode in the charging band is transferred to the discharge electrode 5.
It is configured to be collected on the surface of a flat plate 2 constituting the.

However, the electrostatic precipitator with the above configuration has two parts: a charging part in which a large number of needle-like pieces 4a and 4b are simply arranged side by side at a predetermined pitch in the vertical direction, and an electric field part in which only an electric field is applied without corona discharge. It will be constructed by. As a result, the characteristics of the electrostatic precipitator determined by the amount of charge become extremely low, and the desired characteristics cannot be obtained unless multiple units are connected in series. I become confused.

In addition, as shown in Fig. 1, dust collection electrodes 1a, 1b
Since the dust is collected in only a portion of the wafer, there is a problem in that when high resistance dust is handled, a back corona occurs and dust collection cannot be carried out.

In order to solve these problems, the inventor of the present application has proposed an electrostatic precipitator based on the Hurler method as shown in Japanese Utility Model Publication No. 37243/1983. This electrostatic precipitator, as shown in Figure 2,
A discharge part 9 in which discharge bodies 7 having needle-shaped pieces 6 and hollow metal rods 8 are arranged in parallel alternately, and a dust collection part 11 in which hollow metal rods 10 are arranged in parallel along the discharge part 9. It is structured accordingly. In the electrostatic precipitator configured in this way, a strong corona discharge is generated from the tip of each needle-like piece 6 over almost the entire surface of the dust collecting section 10, and the dust collecting section 10 is connected to the hollow metal rod 8.
Since the dust collection area increases as a whole, the dust collection efficiency is greatly improved compared to the case shown in FIG.

However, even in the electrostatic precipitator with the above configuration, when high-resistance dust such as dust discharged from a coal boiler is collected, back corona is generated and the dust is collected because the electric charge charged in the dust is no longer discharged. I have a problem where I can't do the job. Furthermore, when dealing with a gas flow containing an ignitable substance such as tar, there is a problem that the substance collected in the dust collecting section may ignite due to spark discharge or the like.

Therefore, an object of the present invention is to provide an electrostatic precipitator suitable for collecting high-resistance dust.

Another object of the invention is to provide an electrostatic precipitator suitable for collecting dust of ignitable substances.

In order to achieve such an object, the present invention constitutes a dust collecting section by arranging two net-like bodies in parallel, and also provides a nozzle for spraying water between these two net-like bodies. It is something that EMBODIMENT OF THE INVENTION Hereinafter, the electrostatic precipitator according to the present invention will be explained in detail using the drawings.

FIG. 3 is a plan view of essential parts showing an embodiment of the electrostatic precipitator according to the present invention. In the figure, reference numeral 12 denotes a dust collecting section, and as shown in FIG. 4, net-like bodies 15 each having a net 14 stretched over a frame 13 are arranged in parallel at predetermined intervals. 16 is a nozzle that sprays water between the two net-like bodies 15 that constitute the dust collection section 12, and 17 is a discharge section that is arranged in parallel to the dust collection section 12, as shown in FIG. Conductive plates 19 having serrated portions 18 are arranged side by side at predetermined intervals and integrated.

In the electrostatic precipitator configured in this way,
When a high DC voltage is applied between the dust collection section 12 and the discharge section 17, a corona discharge is generated at each tip of the sawtooth section 18 of the conductive plate 19 constituting the discharge section 17.

In this state, for example, if a gas containing dust is flowed in the direction of the arrow, this dust will be transferred to the dust collecting section 1.
It is adsorbed to the net-like body 15 that constitutes the structure 5. In this case, if a small amount of high-resistance dust is collected in the dust collecting section 15, it is difficult to discharge the charged electric charge, so that it becomes an electric charge accumulation body and a back corona phenomenon occurs, making it impossible to collect dust. . here,
When water (aqueous solution) is sprayed from the nozzle 16, the spray passes through the mesh of the net-like body 15 and spreads to the outer portion as shown by B in FIG. After this spray is charged by corona discharge, it is sucked into the dust collecting section 12 formed by the mesh body 15. As a result, since the spray body covers the surface of the net 14 constituting the net-like body 15,
The high-resistance dust collected in the dust collecting section 12 has moisture adsorbed thereto, and its resistance value is lowered. For this reason, dust whose resistance has been lowered will not generate back corona, and stable dust collection will be easily performed. In addition, since the sprayed water flows in a film-like manner covering the entire surface of the net 14 constituting the net-like body 15, the collected dust can be easily washed away, and especially tarry dust can be collected. It is suitable for cases where there is a lot of dust. Furthermore, since the water spray body covers the area around the dust collecting section 12, when collecting ignitable substances such as tar, the risk of ignition due to sparks, etc. can be greatly reduced, and along with this, This makes it easier to collect dust from ignitable substances.

In addition, when the dust is water-generating, a liquid such as a sea surfactant may be mixed, and water spraying can be carried out continuously or intermittently as necessary.
Moreover, the discharge part does not necessarily have to be an assembly of conductive plates having sawtoothed parts, and may have any structure. Furthermore, in the above embodiments, the net itself was used as the net-like body, but punch metal is also included in the net-like body here.

As explained above, the electrostatic precipitator according to the present invention is an excellent device that can easily collect high-resistance dust and prevent the risk of ignition when collecting ignitable substances. have an effect.

[Brief explanation of drawings]

1 and 2 are a plan view and a perspective view of a main part showing an example of a conventional electrostatic precipitator, FIG. 3 is a plan view of a main part showing an embodiment of an electrostatic precipitator according to the present invention, and FIG. This figure is a side view showing an example of the dust collection section 12 shown in FIG. 3, and FIG. 5 is a perspective view showing an example of the discharge section shown in FIG. 3. 12...Dust collection section, 13...Frame body, 14...
Net, 15...Network, 16...Nozzle, 17...
Dust collection part, 18... Serrated part, 19... Conductive plate.

Claims (1)

[Scope of Claims] 1. In an electrostatic precipitator in which a dust collection part and a discharge part are arranged facing each other with a predetermined distance apart, the dust collection part is composed of two mesh-shaped sheets arranged facing each other and separated by a predetermined distance from each other. 1. An electrostatic precipitator comprising a body, and having a nozzle near the net-like body for spraying a liquid in a mist between the two net-like bodies. 2. The electrostatic precipitator according to claim 1, wherein the discharge section is constituted by an assembly of conductive plates arranged side by side having serrated portions on the sides. 3. The electrostatic precipitator according to claim 1, wherein the nozzle sprays the liquid intermittently.