JPS6044065A - Dust collecting apparatus - Google Patents

Abstract

PURPOSE:To contrive to enhance dust collecting efficiency, by providing an electrostatic filter part to the downstream side of an electric dust collector, and collecting dust not collected by the electric dust collector by the electrostatic filter part to again collect the dust while sending the same to the upstream side of the electric dust collector. CONSTITUTION:Dust-containing exhaust gas is flowed into an electric dust collector 11 where the greater part of dust is removed and the exhaust gas containing residual dust with a small particle size is sent to an electrostatic filter part 12. This filter part 12 is formed of a filter 15 comprising a non-conductive material, dampers 16, 17 for closing the gas flow lines provided to the upstream and downstream sides of the filter 15 and a dust removing mechanism 30. The dust removed in the filter part 12 is guided to the upstream side of the dust collector 11 by a recirculation passage 26. By this apparatus, dust is removed with good efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dust collector for removing dust contained in exhaust gas from a coal-fired boiler or the like.

Generally, electrostatic precipitators have been used to remove dust contained in exhaust gas from boilers and the like. However, the dust collection efficiency of this electrostatic precipitator changes depending on the particle size of the dust, and as shown in FIG. 1, it decreases the most when the particle size of the dust is around 0.1 micron. For this reason, in a coal-fired boiler where the particle size distribution of dust is wide, there is a drawback that the dust collection efficiency is low. Therefore, in order to efficiently collect dust in such a case, it is necessary to increase the capacity ω of the electrostatic precipitator to increase the dust collection efficiency, as shown in Figure 2, which would make the capacity unnecessarily large. I had to.

Furthermore, there is an electrostatic filter device that can efficiently collect dust with a small particle size. As shown in FIG. 3, this device includes an ionization section 1 and a filter 2 made of a non-conductive material provided on the downstream side of the ionization section 1. The ionization section 1 is composed of a dust collection electrode 3.3 and a discharge electrode 4, and applies a high voltage between them to charge the dust.
An electric field is formed in the void inside the filter 2, and this dust is attracted by Coulomb force. Although this electrostatic filter device can efficiently collect dust with a small particle size, it is difficult to collect highly concentrated dust, and it is also difficult to remove the adsorbed dust.

For this reason, this electrostatic filter device could not treat exhaust gas from coal-fired boilers or the like.

The present invention has been made based on the above circumstances, and its object is to provide a dust collector that has a wide particle size distribution and is capable of efficiently collecting dust at a high concentration.

That is, in the present invention, an electrostatic filter section is provided on the downstream side of an electrostatic precipitator, and this electrostatic filter section includes a filter made of a non-conductive material, and a gas flow path provided on the upstream and downstream sides of the filter. A damper that closes and a dust removal mechanism that removes dust attached to the filter are provided, and a recirculation passage is provided that guides the dust removed by the dust removal mechanism in the electrostatic filter section to the upstream side of the electrostatic precipitator. It was established. Therefore, most of the large particle size dust is collected by the electric collector 1tl, and the remaining small particle size dust is collected by the electrostatic filter section, so that dust with high concentration and a wide particle size distribution can be efficiently captured. can be collected. In addition, the dust adsorbed by the filter in the electrostatic filter section is removed by the dust removal mechanism, so that the gas processing capacity is not reduced, and the removed dust is passed through the recirculation passage to the upstream side of the electrostatic precipitator. Since the dust 1 is sent to and collected again, the removed dust 1 is not scattered to the dust 1, and the dust collection efficiency is further improved.

An embodiment of the present invention will be described below with reference to FIGS. 4 to 8. Reference numeral 11 in the figure is an electrostatic precipitator, which has the same configuration as the conventional one. An electrostatic filter section 12 is provided downstream of this electrostatic precipitator 11. This electrostatic filter section 12 is constructed as follows. That is, inside this electrostatic filter section 12, there are a plurality of partition walls 13,
A plurality of filter chambers 14 are formed in parallel to each other with respect to the gas flow. Filters 15 are accommodated in these filter chambers 14, respectively. These filters 15・
... is a porous material made of non-conductive material.

Inlet dampers 16 and outlet dampers 17 are arranged on the upstream and downstream sides of these filter chambers 14, respectively. These inlet dampers 1
6... and the outlet damper are rotated by motors 22... to open and close the inlet and outlet sides of the filter chambers 14... Note that an ionization section 18 is provided upstream of these filter chambers 14 . . . , and dust in the exhaust gas is given an electric charge when passing through this ionization section 18 . Furthermore, dust removal mechanisms 30 are provided in the filter chambers 14, respectively. 23... is the air nozzle, and filter 1
It is provided on the downstream side of 5. These air nozzles 23 are provided to be movable up and down, and a horizontal pipe 20 is provided at the lower end thereof in the horizontal direction, and a plurality of nozzles 21 are provided in this horizontal pipe 20 to protrude toward the filter 15. ing. Further, a guide vane 25 is provided on the upstream side of the filter 15.
is provided, and this guide vane 25 is connected to the air nozzle 2.
It is configured to move up and down in synchronization with 3. Then, high-pressure air is ejected from the nozzles 21 of the air nozzles 23 toward the filter 15, and this air removes dust attached to the filter 15, and the air containing this dust is transferred to the guide vane. deflected downward by 25;
It is sent to the lower part of the filter chamber 14... A recirculation passage 26 is connected to the lower part of these filter chambers 14 through on-off valves 31.

This recirculation passage 26 is connected to the upstream side of the electrostatic precipitator 1-1. And this recirculation passage 26
A blower 27 is provided in the middle.

Next, the operation of this embodiment will be explained. The exhaust gas containing dust first flows into the electrostatic precipitator 11, and most of the dust with large particle sizes is collected by this electrostatic precipitator. ! It is collected and removed in step 111. The remaining small-sized dust particles are adsorbed and removed by the filters 15 of the electrostatic filter section 12. Therefore, even dust with a wide particle size distribution can be efficiently collected. Further, since most of the dust is collected by the electrostatic precipitator 11 and the remaining dust is collected by the electrostatic filter section 12, even highly concentrated dust can be treated. Then, the filter 15 of the electrostatic filter section 12
When dust accumulates in the filter chamber 14, the inlet damper 16 and outlet damper 17 of one of the filter chambers 14 are closed, and the high pressure ejected from the air nozzle 23 of the dust removal mechanism is closed. Remove this dust by air.

The removed dust is sent from the lower part of the filter chamber 14 through the recirculation passage 26 to the upstream side of the electrostatic precipitator 11 by the blower 27, and is collected by the electrostatic precipitator 11 and the electrostatic filter section 12. Therefore, the removed dust will not be scattered again and the collection efficiency will not be reduced.

As described above, the present invention provides an electrostatic filter part on the downstream side of an electrostatic precipitator, and this electrostatic filter part includes a filter made of a non-conductive material, and gas flow filters provided on the upstream and downstream sides of the filter. A dust removal mechanism is provided to remove dust adhering to the filter, such as a damper that blocks the passage.
Further, a recirculation passage is provided for guiding the dust removed by the dust removal mechanism within the electrostatic filter section to the upstream side of the electrostatic precipitator. Therefore, most of the large particle size dust is collected by the electrostatic precipitator, and the remaining small particle size dust is collected by the electrostatic filter section, so even dust with high concentration and a wide particle size distribution can be efficiently collected. can do. In addition, the dust adsorbed on the filter of the electrostatic filter section is removed by the dust removal mechanism, so that the gas processing capacity is not reduced, and the removed dust is passed through the recirculation passage to the upstream side of the electrostatic precipitator. Since the removed dust is sent to and collected again, the removed dust does not scatter, and the dust collection efficiency is further improved, which has great effects.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between dust particle size and collection efficiency.
FIG. 2 is a diagram showing the relationship between the capacity of the electrostatic precipitator and the dust collection efficiency, and FIG. 3 is a schematic diagram of the electrostatic filter device. 4 to 8 show one embodiment of the present invention, FIG. 4 is a schematic diagram of the overall configuration, FIG. 5 is a sectional view taken along the line v-■ in FIG. 4, and FIG. Figure 7 is a cross-sectional view taken along line ■-■ in Figure 6, Figure 8 is a cross-sectional view taken along line ■-■ in Figure 6, and Figure 8 is a cross-sectional view taken along line ■-■ in Figure 6.
It is a cross-sectional view along the -■ line. 11... Electrostatic precipitator, 12... Electrostatic filter section, 14... Filter chamber, 15...
... Filter, 16 ... Population damper, 18 ...
...Outlet damper, 26...Recirculation passage, 3
0...Dust removal mechanism. Applicant sub-agent Patent attorney Takehiko Suzue -〇- 1st r, To, + 1+o 100 (P)

Claims (1)

[Claims] An electrostatic filter section is provided on the downstream side of the electrostatic precipitator, and the electrostatic filter section includes a filter made of a non-conductive material, and dampers provided on the upstream and downstream sides of the filter to block the gas flow path. A dust removal mechanism for removing dust attached to the filter is provided, and a recirculation passage is provided in the electrostatic filter section to guide the dust removed by the dust removal mechanism to the upstream side of the electrostatic precipitator. Dust collection @ place.