JP2000140690A - Dry type dust collector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove dust, to make the collector compact as a whole and to reduce cost by integrating a rough electric dust collector with a dielec tric rod type dust collector. SOLUTION: This dry type dust collector includes a 1st stage rough electric dust collector 10 for electrostatically charging and collecting dust in a dust- containing exhaust gas, a 2nd dust collector 16 of dielectric rod type for attracting and collecting the dust particles in the waste gas, which is not collected in the 1st stage rough electric dust collector, by applying DC high voltage, and a means for shaking off the dust particle deposited on the dielectric rod 12. As the means for shaking off the dust particle, a hammering part and a scraper are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry dust remover for removing dust from exhaust gas containing dust discharged from a boiler or a combustion furnace.

[0002]

2. Description of the Related Art The most common type of dust collector is an electric dust collector, which is used in a wide range of fields by utilizing its low pressure loss, high performance, and maintenance-free characteristics. This electric dust collector charges the dust in the exhaust gas by corona discharge, moves the charged dust to the dust collection electrode by Coulomb force, and collects and accumulates it on the dust collection electrode. Had to move. Therefore, as a dry type dust collecting apparatus for adhering and collecting such dust by reducing the moving distance of such dust, for example, as a device for continuously removing dust from dust-containing exhaust gas, it is disposed between electrodes to which a high voltage is applied. An electrostatic filter that collects dust by passing dust-containing exhaust gas between filled fillers is known.

[0003] Japanese Patent Publication No. 56-48214 discloses a method in which a particulate filler is filled between electrodes to which a high voltage is applied, and exhaust gas containing dust is passed through the packed layer to remove dust in the exhaust gas. An apparatus for collecting dust and a method for collecting dust using the apparatus are disclosed. Further, JP-A-63-27056
No. 0 describes a packed bed dust collecting apparatus that continuously improves the dust collecting performance by continuously supplying a charge having a polarity opposite to that of the forcibly charged dust to the insulator spheres in the packed bed. When the dust layer adheres to the packed layer and collects it, the charged layer consists of a high-dielectric-constant insulator sphere that is charged in the opposite polarity to the dust particles. The charging device to be provided is provided upstream of the packed bed in the flow of the exhaust gas.

[0004] The above-mentioned dry type dust collecting apparatus is an expensive equipment, and when a large amount of dust is treated by dust collection using only an electrostatic filter or a packed bed, the dust removing efficiency is reduced immediately and the pressure loss is reduced. The increase is also large. That is, conventionally, a charging device is provided on the upstream side of the packed layer to charge the dust, but if only the charging of the dust is performed, the amount of the dust to be processed by the packed layer is large, and the performance immediately deteriorates. Similarly, the pressure loss rises quickly. Therefore, if the amount of dust is large, it is necessary to increase the capacity of the dust collection equipment, and not only the site area but also the installation cost and the operating cost increase.

[0005] Therefore, in order to solve the above-mentioned difficulties, it is required to reduce the capacity of the dry dust collection equipment. However, it is not preferable that the dust-removing performance is reduced in accordance with the reduction in the capacity of the dry dust collecting equipment. Further, in the conventional apparatus, since the insulated spheres in the packed bed are replaced by the gate valve at regular time intervals, there is a disadvantage that the replacement operation is troublesome.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems of the prior art, and has been described in view of the above.
It is an object of the present invention to provide an inexpensive and highly efficient exhaust gas dust removal facility capable of achieving compactness.

[0007]

In order to solve the above-mentioned problems, the present invention provides a second-stage dust collecting device which performs charging of dust and rough-dust collection by a first-stage roughing dust collector. The load of dust removal was reduced. Therefore, according to one aspect of the present invention, a first-stage roughing electrostatic precipitator for charging and collecting dust in dust-containing exhaust gas, and applying a high DC voltage to the first-stage roughing precipitator. The second of the dielectric rod type for adhering and collecting dust particles in the exhaust gas not collected by the electrostatic precipitator.
There is provided a dry dust remover including a step dust collector and means for removing dust particles attached to the dielectric rod.

In the case of the dielectric rod type in the present invention, a large amount of dust can be collected by providing a dielectric rod type dust collector and a roughing electric dust collector adjacent thereto upstream. By reducing the dust removal load applied to one of the devices compared to the case of dust removal using only a rough dust collection device or a dielectric rod type collection unit, it is possible to reduce the size of the entire equipment.
Further, since the structure of the dielectric rod type dust collecting unit itself is relatively simple, the cost of installation and maintenance can be reduced. The dust-containing exhaust gas is passed through an upstream roughing electrostatic precipitator, the dust in the dust-containing gas is charged in advance, and the dust is partially collected. By adhering and collecting the particles on the body rod, particles having a particle size of several μm or less, which are difficult to be collected by the roughing electrostatic precipitator, are collected, and the dust removing efficiency is improved as a whole.

Further, according to the present invention, in the above-described second-stage dust collecting apparatus, a hammer is connected to a lower part of the dielectric rod group in order to remove dust particles attached to the dielectric rod. Dust particles can be removed periodically. Further, according to the present invention, in the above-described second-stage dust collector,
The dust particles can be removed regularly by sliding a perforated plate scraper having a diameter substantially the same as the diameter of the dielectric rod in order to wipe off the dust particles attached to the dielectric rod.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The dry dust remover of the present invention will be further described below with reference to the drawings, but it goes without saying that the present invention is not limited to this example. First, FIG. 1 shows a schematic cross-sectional view of the configuration of the dry dust remover of the present invention. FIG. 1 is a sectional view of the device of the present invention as viewed from above. In the first-stage coarse dust collection device 10, exhaust gas containing dust
While pre-charging the dust in the exhaust gas through
Coarse dust, mainly dust having a size of 10 μm order or more, is roughly removed. In the coarse dust collecting device 10, by pre-charging the dust and roughly removing the dust, comprehensively good dust collecting efficiency including the second stage dust collecting device can be obtained.

The first-stage coarse electric precipitator 10 includes a flat plate ground electrode (dust collecting electrode) 7 and a high voltage electrode (discharge electrode) 8. The high voltage electrode 8 may have a linear shape having various cross-sectional shapes. When a voltage is applied to the high-voltage electrode 8, corona discharge is generated, and the passing dust is charged. As a result, dust charged by the Coulomb force is collected on the ground electrode 7. It is preferable that the flat plate ground electrode (dust collection electrode) 7 be disposed substantially vertically so that the collected dust can be easily removed after a suitable time by a known means such as hammering. . In order to increase the efficiency of collection, it is preferable to have a certain area. Therefore, the number of the high-voltage electrodes (discharge electrodes) 8 is preferably two or more per one ground electrode, and more preferably about three to five.

The dust particles thus charged and remaining in the exhaust gas without being collected are collected by the first-stage coarse dust collecting device 10 described above.
And a second-stage dust collector 1 having a dielectric rod group provided downstream of the exhaust gas flow, integrated by a casing 9.
6 to collect dust particles of 10 μm or less. According to the present invention, the perforated plates 11, 1
By applying a voltage between 1 ', a horizontal electric field is generated. The perforated plates 11 and 11 ′ may have any structure such as a wire mesh that can pass gas. At this time, a high voltage of about 50 kV is applied. Due to this electric field, the dielectric rod 12 undergoes dielectric polarization, and the charged dust that has passed through the first-stage coarse dust collector 10 adheres and is collected on the surface of the dielectric rod by Coulomb force.

The dielectric rod in the dry dust collector of the present invention has a length of 3 to 7 m, preferably about 5 m, and a diameter of 3 to 1 m.
0 mm, preferably about 5 mm in diameter. As the dielectric rod, it is desirable to use a metal rod coated with an insulating material such as Teflon (trade name). The above-mentioned dielectric rod has several hundreds to ten at a constant pitch of 5 to 10 mm.
Approximately 00 are provided. The length of the second-stage dust collector 16 along the exhaust gas flow is several meters.

As shown in FIG. 2, the dust particles adhering to the dielectric rod 12 drop into the hopper 14 by regularly hammering the hammer 20 and are collected in the direction of arrow 15. . When the hammer 20 is regularly hammered to remove dust particles attached to the dielectric rod 12, a method such as rotating a hammer (not shown) is used. Furthermore, it is also effective to shake the hammer by a vibrator (not shown) in order to promote the action of the hammer to remove dust particles from the hammer as required.

Further, in FIG. 3, dust particles adhering to the dielectric rod 12 are scraped off by the movable scraper 18 and collected by the hopper 14 as described above. The scraper 18 has a plurality of holes having a size through which the dielectric rod 12 passes. As shown in FIG. 3, the scraper 18 is moved up and down to scrape off dust particles adhering to the dielectric rod 12.

[0016]

As apparent from the above description, according to the present invention, a large amount of dust is trapped by integrally providing a dielectric rod type dust collector and a coarse dust collector upstream of the dust collector. It is possible to collect the dust and reduce the dust removal load on one of the devices compared to the case of dust removal using only a rough dust collection device or a dielectric rod, thereby achieving downsizing of the entire dust removal equipment. In other words, the electric dust collector does not require a high degree of dust collection because of the purpose of charging and roughing the dust, and can reduce the dust removal load. Further, the dust collection by the dielectric rod can reduce the dust removal load by treating the low-concentration dust roughly removed on the upstream side, so that a small capacity is required. And even if these are comprehensively combined, it is possible to achieve a reduction in the size of the entire dust removing facility as compared with the scale of the apparatus that has been processed by one conventional apparatus.

Further, after the dust-containing exhaust gas is passed through an upstream roughing electrostatic precipitator to charge the dust in the dust-containing gas in advance,
By adhering and collecting the charged dust on the dielectric rod with a dielectric rod type dust collector, dust having a particle diameter of several μm or less that is difficult to be collected by the roughing electric dust collector is collected. This makes it possible to improve dust removal efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of a dry dust remover according to the present invention, which is a horizontal plane viewed from above.

FIG. 2 is a conceptual diagram (hamming method) showing an embodiment of a dry dust remover according to the present invention.

FIG. 3 is a conceptual diagram (scraping method) showing an embodiment of a dry dust remover according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 7 ground electrode 8 high voltage electrode 9 casing 10 first stage coarse dust collector 11, 11 'perforated plate 12 dielectric rod 13 high voltage generator 14 hopper 15 collected ash 16 second stage dust collector of dielectric rod group 18 Scraper 20 Hammering section G Inflow direction of dust-containing exhaust gas

Continued on the front page (72) Inventor Yasuminori Ueda 2-1-1 Shinama, Arai-machi, Takasago City, Hyogo Prefecture Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Keishiro Saito 2-1-1, Niihama, Arai-machi, Takasago City, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Research Laboratory F-term (reference) 4D054 AA01 BA01 BA08 BC14 DA02 DA04

Claims (3)

[Claims] 1. A first-stage roughing electrostatic precipitator for charging and collecting dust in a dust-containing exhaust gas, and a first high-level coarse electric precipitator by applying a high DC voltage. A dry dust removing apparatus including a second-stage dust collector of a dielectric rod type for adhering and collecting dust particles in exhaust gas that has not been collected, and means for removing dust particles adhering to the dielectric rods . 2. A means for removing dust particles adhering to said dielectric rod is a hammer connected to a lower part of said dielectric rod of said second-stage dust collector. The dry dust remover according to claim 1. 3. A dry dust removing apparatus according to claim 1, wherein said means for removing dust particles adhering to said dielectric rod is a perforated plate scraper having substantially the same diameter as said dielectric rod. .