JP2011183359A - Electrostatic precipitator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic precipitator that attains a long life of brushes by suppressing wear of the brushes to the minimum while high dust collection efficiency is maintained. <P>SOLUTION: The electrostatic precipitator includes: a casing that makes dust-containing gas flow from the entrance to the exit of the gas; a large number of discharge electrodes that are hung in a gas flow passage to be a dust collecting region in the casing; and movable electrodes that circulate with a loop formed by a plurality of dust collecting electrode plates suspended on a pair of endless chains and that have a brushing means for brushing at a prescribed position the face of the circulating dust collecting electrode plates. The brushing means is characterized in that it is composed of fixed brushes that brush the dust collecting electrode plates of the movable electrodes arranged in a high dust concentration partition of the dust collecting region in the casing, and of rotary brushes that brush the dust collecting electrode plates of the movable electrodes arranged in a low dust concentration partition. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrostatic precipitator having a moving electrode, and in particular, a large number of discharge electrodes suspended at a predetermined interval in a casing, and a large number of dust collectors arranged around these discharge electrodes. The present invention relates to an electric dust collector equipped with an electrode plate.

  This type of electrostatic precipitator is known as an electrostatic precipitator for removing dust in, for example, boiler exhaust gas from a thermal power plant and exhaust gas from various furnaces for iron making. The schematic structure shown in Patent Document 1 is shown in FIG. Description will be made with reference to FIG.

  In FIG. 6, the moving electrode type electrostatic precipitator 10 includes a casing 12, a hopper 13 below the casing, a number of metal discharge frames (discharge electrodes) 14 disposed in the casing 12, and a number of metals. The exhaust gas 17 introduced into the casing 12 from the inlet 16 is removed by the principle of electrostatic dust collection and discharged from the outlet 18. Dust collected by the moving electrode 15 falls into the hopper 13 and is taken out from the discharge port 20 by a mechanism (not shown).

  FIG. 7 is a view taken along the line AA of FIG. 6, and a large number of discharge frames 14 are provided in the casing 12 at predetermined intervals via suspension frames 24 suspended from the insulator 22 shown in FIG. It is suspended. In addition, a large number of moving electrodes 15 that circulate every other discharge frame 14 are provided.

  FIG. 8 is a perspective view showing the structure of the movable electrode 15. A pair of endless chains 30, 30 are stretched between the upper drive wheel 26 and the lower roller 28, and the pair of endless chains 30. 30, a plurality of dust collecting electrode plates 32 are suspended and suspended at the position of the intermediate portion 33 which is vertically long in the moving direction, and the plate surface is arranged along the flow of gas (thick arrow). As a whole, a loop is formed. The drive shaft 34 of the drive wheel 26 is rotated by a drive mechanism (not shown), and the rotation of the drive shaft 34 is transmitted to a pair of endless chains 30 and 30 meshing with the drive wheel 26 to form a plurality of dust collecting bodies forming the loop. The electrode plate 32 moves around every other discharge frame 14.

  FIG. 9 is a layout view of the lower part of the moving electrode 15, and the dust collecting electrode plate 32 suspended and lowered by the endless chain 30 makes a U-turn at the position of the lower roller 28 and starts to rise. A pair of rotating brushes 36 and 38 (hereinafter, the pair of rotating brushes are collectively referred to as brush means and denoted by reference numeral 40) at a position sandwiching the dust collecting electrode plate 32 immediately after the ascent is provided for each lane of the moving electrode 15. Is arranged. The brushes 36 and 38 are made by implanting a metal brush on the rotating shaft, and the brush 36 is rotated clockwise and the brush 38 is counterclockwise so as to scrape the dust adhering to the surface of the dust collecting electrode plate 32 downward. Rotate around. The dust collecting electrode plate 32 from which the dust adhered to the surface has been removed by the brush means 40 is sequentially raised, and the dust in the exhaust gas is collected on the surface by the principle of electric dust collection in the discharge region where the discharge frame 14 is, It will descend again.

  Patent Document 2 discloses an electric dust collector using a fixed brush. In this technique, a fixed brush is pressed and brought into contact with a metal net of a dust collecting electrode by its own weight or weight, and dust is scraped off.

JP 2001-246286 A JP 2003-62486 A

  In Patent Document 1, since the brush means is composed of a rotating brush and dust adhering to the surface of the dust collecting electrode plate 32 is dynamically scraped off, the amount of dust scraping is large, but the amount of wear of the brush is large. When the amount of wear of the brush increases, the amount of dust scraped off decreases, the dust collection rate on the dust collection electrode plate decreases, and the dust collection efficiency deteriorates. Moreover, the expense and trouble of replacement | exchange of a brush means will also be needed. The amount of wear of the brush is known to increase as the dust concentration increases, and this indicates that the higher the dust concentration, the greater the amount of dust collected (thickness) on the dust collection electrode plate. This is because friction increases.

  In Patent Document 2, the structure is simple because of a fixed brush that is flocked. However, since the brush means statically scrapes the dust, the friction with the dust is less than that of the rotating brush, so the amount of wear of the brush is small. On the other hand, the amount of dust scraping is reduced.

  The present invention provides an electrostatic precipitator that utilizes the characteristics of the rotating brush and the fixed brush and extends the life of the brush by minimizing the amount of wear of the brush while maintaining a high dust collection rate. With the goal.

In order to solve the above problems, the present invention provides a casing for flowing a dust-containing gas from an inlet to an outlet of a gas, a number of discharge electrodes suspended in a gas flow path serving as a dust collection area in the casing, An electrostatic precipitator equipped with a moving electrode having brush means for forming a loop around a plurality of dust collecting electrode plates suspended from an endless chain and brushing the surface of the circulating dust collecting electrode plate at a predetermined position In
The brush means includes a fixed brush for brushing a dust collecting electrode plate of a moving electrode disposed in a high dust concentration section of the dust collecting area in the casing, and a dust collecting of the moving electrode disposed in a section having a low dust concentration. It is characterized by comprising a rotating brush that brushes the electrode plate.

  Further, in the electric dust collector described above, the fixed brush is disposed so as to brush a dust collecting electrode plate of a moving electrode disposed in a section upstream of the dust-containing gas flow, and the rotating brush includes a dust-containing electrode. The dust collecting electrode plate of the moving electrode arranged in the downstream section of the gas flow is arranged to brush.

  Further, in the above electric dust collector, the moving electrode brushed by the fixed brush and the moving electrode brushed by the rotating brush are circulated by an independent drive system. And

  The electric dust collector is characterized in that the moving electrode brushed by the fixed brush and the moving electrode brushed by the rotating brush are circulated at different speeds.

In order to solve the above problems, the present invention provides a casing for flowing a dust-containing gas from an inlet to an outlet of a gas, a number of discharge electrodes suspended in a gas flow path serving as a dust collection area in the casing, An electrostatic precipitator equipped with a moving electrode having brush means for forming a loop around a plurality of dust collecting electrode plates suspended from an endless chain and brushing the surface of the circulating dust collecting electrode plate at a predetermined position In
The brush means includes a first brush for brushing a dust collecting electrode plate of a moving electrode disposed in a higher dust concentration section of the dust collection area in the casing, and a moving electrode disposed in a lower dust concentration section. The second brush for brushing the dust collecting electrode plate is characterized in that the first brush is composed of a brush having a smaller amount of wear than the second brush.

  Further, in the electric dust collector described above, the first brush is disposed so as to brush a dust collecting electrode plate of a moving electrode disposed in an upstream section of the dust-containing gas flow, and the second brush includes: The dust collecting electrode plate of the moving electrode arranged in the downstream section of the dust-containing gas flow is arranged to brush.

  In the above electrostatic dust collector, the moving electrode brushed by the first brush and the moving electrode brushed by the second brush are circulated by an independent drive system.

  In the above electrostatic dust collector, the moving electrode brushed by the first brush and the moving electrode brushed by the second brush are circulated at different speeds.

  According to the present invention, it is possible to maintain a high dust collection rate for a long period of time by minimizing the amount of abrasion of the brush by appropriate arrangement of the fixed brush and the rotating brush on the moving electrode.

It is a perspective view which cuts out one part and shows the whole structure of the Example of this invention. It is a detailed view of the brush means. It is a related figure of the arrangement | sequence of a brush means, operation time, and a dust collection rate. It is a related figure of the operation time of various brushes, and a dust collection rate. It is a related figure of the dust concentration of various brushes, and the amount of brush wear. It is a sectional side view which shows the general structure of an electric dust collector. It is an AA arrow line view of FIG. It is a perspective view which shows the general structure of a movement electrode. FIG. 5 is a general arrangement view of a lower part of a moving electrode.

  FIG. 1 is a perspective view showing a part of the entire electrostatic precipitator according to the embodiment of the present invention. Components denoted by the same reference numerals as those shown in FIGS. 6 to 8 described in the section of the background art indicate the same elements.

  In FIG. 1, exhaust gas (dust-containing gas) 17 introduced from the inlet 16 into the casing 12 is removed by the principle of electrostatic dust collection and discharged from the outlet 18. Dust collected by the moving electrode falls into the hopper 13 and is taken out by a mechanism (not shown). Two sets of moving electrodes are arranged along the flow direction of the dust-containing gas in the casing 12, as indicated by 15a and 15b. In this case, two or more sets of moving electrodes may be arranged according to the dust collection capability.

  A large number of moving electrodes 15a are arranged in the upstream section 1 of the gas flow path that is a dust collection area in the casing 12 so as to intersect with the gas flow. A plurality of moving electrodes arranged at intervals so as to intersect with each other are denoted by 15b. A plurality of dust collecting electrode plates 32a and 32b are suspended from each moving electrode 15a and 15b via endless chains 14a and 14b, respectively, and discharge electrodes 14a and 14b are respectively disposed on the inner sides of the respective collecting electrode plates. Is suspended. In FIG. 1, two sections 1 and 2 are provided in the gas flow path of the casing 12 and the section 2 is the final section. However, when the concentration of the dust-containing gas is high, three or more sections may be provided. good.

  The movable electrode 15a disposed in the section 1 includes a fixed brush 3a (brush means, first brush) disposed so as to brush the lower dust collecting electrode plate 32a. The movable electrode 15b disposed in the section 2 includes a rotating brush 3b (brush means, second brush) disposed so as to brush the lower dust collecting electrode plate 32b. The fixed brush 3a and the rotating brush 3b have the structure shown in the detailed view of the brush means in FIG.

  The fixed brush 3a shown in FIG. 2 (a) has a long and long shape in the width direction (perpendicular to the paper surface) of the dust collecting electrode plate 32a and uses its own weight or a weight (not shown) to collect the dust collecting electrode plate 32a. By applying a constant pressing force to the entire width direction, the dust 6a adhering to the dust collecting electrode plate 32a moving in the direction of the arrow acts to be scraped off. The rotating brush 3b shown in FIG. 2 (b) is composed of a long round shaft 3c extending in the width direction of the dust collecting electrode plate 32b and a brush single body 3d spirally installed in the circumferential direction on the peripheral surface. The round shaft 3 c is rotationally driven by the motor 7. Further, the rotating brush 3b is rotated by applying a constant pressing force to the entire width direction of the dust collecting electrode plate 32b by a biasing means such as a spring (not shown), so that the dust collecting electrode plate 32b moves in the arrow direction. It is also possible to constitute such that the dust 6b adhering to the surface is scraped off.

  Reference numerals 4a and 4b denote drive systems for driving the moving electrodes 15a and 15b, respectively. Reference numerals 5a (not shown) and 5b denote drive mechanisms thereof. The movable electrodes 15a and 15b are synchronously driven by the drive systems 4a and 4b. Further, the moving electrodes 15a and 15b may be independently driven by the driving systems 4a and 4b.

  In the above-described configuration, the dust-containing gas introduced from the inlet 16 is first collected by the moving electrode 15a disposed in the section 1, and the collected gas is collected by the moving electrode 15b disposed in the section 2. Dust is collected again. Therefore, since the section 1 is filled with the dust-containing gas introduced from the inlet 16, it becomes a section with a high dust concentration, and the section 2 is filled with the gas once collected with the moving electrode 15a, so the dust concentration is low. It becomes a parcel.

  FIG. 3 shows the relationship between the operating time and the dust collection rate when the dust collection rate is measured by changing the arrangement of the brush means in the sections 1 and 2 by the experimental apparatus. In the case of combination 1 in which rotating brushes are arranged in both sections 1 and 2, the dust collection rate decreases from about 2.5 years of operation time, and in combination 3 in which fixed brushes are arranged in both sections 1 and 2, low dust collection The rate is maintained. In the case of the combination 2 in which the fixed brush is disposed in the section 1 and the rotating brush is disposed in the section 2, as shown by a thick solid line, the dust collection rate is slightly lower than the combination 1 before the operation time 2.5 years, but the operation is performed. Even after 2.5 years, the dust collection rate is maintained without decreasing.

  Therefore, it can be seen that when the brush means of combination 2 are arranged, both brushes have little brush wear, and a high dust collection rate is maintained even after an operation time of 2.5 years.

  FIG. 4 shows the relationship between the operating time of the fixed brush and the rotating brush and the dust collection rate similarly measured by the experimental apparatus. The inlet dust concentration is the same as in FIG. FIG. 5 shows the relationship between the inlet dust concentration of the fixed brush and the rotating brush and the amount of brush wear similarly measured by the experimental apparatus.

As shown in FIG. 4, the dust collection rate by the type of the brush shows 90% or more of the dust collection rate by only the fixed brush and decreases with the operation time, but the decrease is small. On the other hand, the dust collection rate using only the rotating brush is better than that of the fixed brush. As shown in FIG. 5, the wear amount of the fixed brush is considerably smaller than that of the rotating brush, and the difference increases as the inlet dust concentration increases. As shown in FIG. 5, in the vicinity of 3.0 g / m ³ _N 1/3 or less. This is because if the dust concentration is high, the dust adhering to the dust collecting electrode plate becomes thick, and this dust promotes the wear of the brush. Further, the sharp decrease in the dust collection rate of the rotating brush shown in FIG. 4 is because the wear of the rotating brush is large as shown in FIG.

  To summarize the above, the fixed brush has less dust scraping amount than the rotating brush, but the dust collection rate is about several percent lower than the rotating brush, and the difference is slight. It is much smaller, about 1/3 of the rotating brush. Therefore, installing a fixed brush with low wear against dust in a section with high dust concentration and installing a rotating brush with a large amount of dust scraping in a section with low dust concentration is a brush with a large amount of dust scraping. As a whole, wear due to dust can be reduced, and a decrease in dust collection rate can be suppressed.

  The combination 2 shown in FIG. 3 takes into account the advantageous characteristics of the fixed brush and the rotating brush described above, and minimizes the amount of wear of the brush while maintaining a high dust collection rate of each brush. It is a plan to make it.

  In FIG. 1, the moving electrode 15a brushed by the fixed brush 3a and the moving electrode 15b brushed by the rotating brush 3b are circulated independently by the drive systems 4a and 4b. The moving electrodes 15a and 15b can be moved around at different speeds. The amount of dust adhering to each dust collecting electrode plate is determined by the dust concentration in each section 1 and 2, and the amount of dust scraping is the pressing force of each brush to the dust collecting electrode plate and the brush and dust collecting electrode plate. Depends on the relative movement speed. In order to maintain the dust collection performance of the entire dust collector, it is easy to determine the dust collection efficiency of each of the moving electrodes 15a and 15b if an appropriate rotation speed can be set.

  DESCRIPTION OF SYMBOLS 1 ... Section with high dust concentration, Section 1, section upstream of gas flow path, 2 ... Section with low dust concentration, section 2, section downstream of gas flow path, 3a ... Brush means, fixed brush, first Brush, 3b... Brush means, rotating brush, second brush, 4a... Drive system for driving the moving electrode of section 1 to rotate. 4b... Drive system for driving the moving electrode of section 2 to rotate. 5a, 5b. ... casing, 14a, 14b ... discharge electrode, 15a, 15b ... moving electrode, 16 ... gas inlet, 18 ... gas outlet, 30 ... endless chain, 32a, 32b ... dust collecting electrode plate.

Claims (8)

A casing for flowing dust-containing gas from the gas inlet to the outlet, a number of discharge electrodes suspended in a gas flow path serving as a dust collection area in the casing, and a plurality of collectors suspended by a pair of endless chains In an electric dust collector equipped with a moving electrode having brush means for forming a loop with a dust electrode plate and rotating around the surface of the circulating dust collection electrode plate at a predetermined position,
The brush means includes a fixed brush for brushing a dust collecting electrode plate of a moving electrode disposed in a high dust concentration section of the dust collecting area in the casing, and a dust collecting of the moving electrode disposed in a section having a low dust concentration. An electrostatic precipitator comprising a rotating brush for brushing an electrode plate. The electric dust collector according to claim 1,
The fixed brush is arranged to brush the dust collecting electrode plate of the moving electrode arranged in the upstream section of the dust-containing gas flow, and the rotating brush is moved in the downstream section of the dust-containing gas flow. An electric dust collector arranged to brush a dust collecting electrode plate of an electrode. The electrostatic precipitator according to claim 1 or 2,
An electric dust collector, wherein the moving electrode brushed by the fixed brush and the moving electrode brushed by the rotating brush are circulated by an independent drive system. The electrostatic precipitator according to claim 3,
An electric dust collector, wherein the moving electrode brushed by the fixed brush and the moving electrode brushed by the rotating brush are circulated at different speeds. A casing for flowing dust-containing gas from the gas inlet to the outlet, a number of discharge electrodes suspended in a gas flow path serving as a dust collection area in the casing, and a plurality of collectors suspended by a pair of endless chains In an electric dust collector equipped with a moving electrode having brush means for forming a loop with a dust electrode plate and rotating around the surface of the circulating dust collection electrode plate at a predetermined position,
The brush means includes a first brush for brushing a dust collecting electrode plate of a moving electrode disposed in a higher dust concentration section of the dust collection area in the casing, and a moving electrode disposed in a lower dust concentration section. An electrostatic precipitator comprising a second brush for brushing the dust collecting electrode plate, wherein the first brush is composed of a brush having a smaller amount of wear than the second brush. The electric dust collector according to claim 5,
The first brush is arranged to brush a collecting electrode plate of a moving electrode arranged in a section upstream of the dust-containing gas flow, and the second brush is arranged in a section downstream of the dust-containing gas flow. An electrostatic precipitator arranged to brush a dust collecting electrode plate of a movable electrode. The electric dust collector according to claim 5 or 6,
The electric dust collector, wherein the moving electrode brushed by the first brush and the moving electrode brushed by the second brush are circulated by an independent drive system. The electric dust collector according to claim 7,
The electric dust collector, wherein the moving electrode brushed by the first brush and the moving electrode brushed by the second brush are circulated at different speeds.

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