JPS6323759A - Electric precipitator - Google Patents

Abstract

1. A dedusting electrostatic precipitator for a horizontal flow of gas, wherein a tubular inlet port (7), which flares in three conical sections (a, b, c) from the cross-section of the gas supply line to the at least ten times larger cross-section of the cylindrical housing (1), vertical platelike collecting electrodes (2) are equally spaced apart in a cylindrical pressure-resisting housing (1) and extend parallel to the main axis of the housing (1) and substantially throughout the available height over the length of the corresponding chord of the circle, corona electrodes (3) tensioned in frames (15) are provided between the collecting electrodes (2) and scraping means (6) are provided, which are pivotally movable about the axis of the housing throughout the lower portion of the housing wall, which portion is provided with dust discharge openings (4), characterized in that the respective smaller diameters d of the conical sections (a, b, c) of the tubular inlet and pipe (7) are related to the diameter D of the housing (1) as 0.24 D =< d3 =< 0.36 D (preferably 0.3 D) 0.36 D =< d2 =< 0.48 D (preferably 0.42 D) 0.90 D =< d1 =< 0.95 D (preferably 0.925 D) and that the intermediate conical section b has three gas-distributing plates (8a to 8c).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electrostatic precipitator for horizontal gas flow, in which vertical flat dust collecting electrodes are arranged at regular intervals parallel to the main axis of the housing in a cylindrical pressure-resistant housing. Discharge electrodes arranged on the frame and extending vertically over substantially the entire effective height, each corresponding to the length of the chord of the circle, are disposed between the collecting electrodes and are stretched over the frame, and are connected to the wall of the housing. The present invention relates to an electrostatic precipitator having a scraper which is swingable about the axis of the housing on a lower region provided with a dust discharge opening.

[Summary of the invention]

The present invention provides an electrostatic precipitator for horizontal gas flow, in which three gas distribution perforated plates having a specific cross-sectional area are provided at the tubular inlet, thereby preventing accumulated dust in the gas flow and forming a flow stagnation space. This makes it possible to obtain a dust collector that does not

PRIOR ART AND THE PROBLEM TO BE SOLVED BY THE INVENTION A precipitator of this type is known from German patent no. The requirements for limited utilization and the elimination of flow stagnation spaces in view of the risk of explosion when flammable and non-flammable gases are supplied alternately are substantially met. Despite that,
Occasional failures still occurred due to deflagrations and weak gas explosions, the cause of which was initially unknown.

Precipitators of this type are used for the dry method of collecting dust from industrially useful gases and exhaust gases, in particular from constantly or occasionally explosive gas mixtures. For example, the flue gas coming from a blast furnace operated under an overpressure of 1.5-2.5 bar is passed through a turbine for 40-200 m to recover energy without the risk of erosion.
It is dedusted in this way so as to relieve the pressure to an overpressure of 80 mbar.

For this purpose, the dust content must be reduced to 5-20 mg/m' beforehand. To maximize the available pressure drop, only electrostatic precipitators with a pressure drop of 1 to 2 mbar are considered. This is because a high-intensity scrubber with comparable separation performance has a pressure drop of 200 to 400 mbar.

Another field of application for precipitators of this type is coal crushing plants, 1 whose exhaust gases can be explosive within certain limits due to their coal dust content. In that case, uncontrolled changes in the gas composition due to fluidization of coal dust deposits or due to sudden infiltration of air must be avoided in any case.

Dust removal from converter flue gases is also particularly dangerous.

This is because, due to the discontinuous operation, the precipitator is passed alternately with combustible gas and ambient air containing only a small amount of the dust-gas mixture. After the combustible gas is removed,
The gases are collected in a container or sent to the gas supply system, while the gases generated intermediately in addition to the original blowing of the converter are cleared and then released into the atmosphere through the chimney. For this purpose, downstream of the precipitator a switching device is used which is controlled over time or by gas composition. Deflagrations that occur upstream of this switching device, converter, and precipitator can cause transient pressure fluctuations in the gas flow, which can cause deposits of dust in the precipitator or in the dust system located upstream. may flake off and become fluidized in the gas stream. Such "transient fluctuations in dust" deteriorate the separation performance of the precipitator on the one hand, and increase the risk of deflagration on the other hand.

Even in dust collectors for converter flue gas, if air suddenly infiltrates during critical periods, or if the flow stagnates due to design flaws, a certain amount of gas with an uncertain composition may accumulate. Deflagration can occur if a portion of the fluid system that has been exposed to air is reactivated by a transient pressure fluctuation. If this happens, it is easy to see that all the measures taken to ensure the separation of the different qualities of gas that change over time and are passed through the precipitator will be in vain.

It is therefore an object of the present invention to improve existing molar collectors by
It is an object of the present invention to provide an electrostatic precipitator which not only meets the requirements in the cylindrical part, but is designed as a whole so that neither accumulated dust is uncontrolled fluidized in the gas flow nor flow stagnation spaces are formed. . Moreover, the design must be as economical as possible to implement for all required dimensions.

[Means for solving problems]

All of the above requirements are fulfilled by providing that the three conical sections extend the cross-sectional area of the gas supply to a cross-sectional area of the cylindrical housing that is at least 10 times larger and that three gas distribution perforated plates are provided in the intermediate conical section. It has surprisingly been found that this can be achieved particularly effectively by providing a tubular inlet having a .

Furthermore, it is proposed to provide a tubular outlet which is constricted by three conical sections to a cross-sectional area of the gas outlet that is at most 1/1 of the size of the cross-sectional area of the cylindrical housing. According to yet another aspect of the invention, the tubular inlet has one or more pressure relief spring loaded dampers. Particularly desirable gas flow and gas distribution are achieved in the electrostatic precipitator of the present invention, in which the respective smaller diameter d of each conical portion of the tubular inlet and tubular outlet is equal to or smaller than the diameter of the housing. Relationship: 0.240≦d, '-0,36D (preferably t L <
LtO, 3D), 0.36D:5d, ≦0.48
D (better (is 0.42D), 0.900≦d1
≦0.95 D (preferably 0.925 D), and the height h of each conical portion of the tubular inlet and tubular outlet has the following relationship with the diameter of the housing: 0.075 D≦h,
≦0.1350 (preferably 0.105 D), 0.
120 D≦h2≦0.200D (preferably 0.1
60 D), 0.045 D≦h, ≦0.075D
(preferably 0.060 D).

The gas distribution perforated plate provided on the surface of diameter d2 is 52 to 60
%, preferably 56%, and the other two gas distribution perforated plates have an open pore area of 54-62%, preferably 58%. Furthermore, a closed dust collection duct with a mechanical conveyor and a crossbar separating the dust outlet openings from each other on the gas side can be arranged below the dust outlet openings. Finally, in order to compensate for transient pressure fluctuations, the gas distribution perforated plate preferably has a movable suspended part that swings in a direction opposite to the gas flow direction.

〔Example〕

The details and advantages of the electrostatic precipitator of the invention will be explained in more detail below by means of the embodiments shown in FIGS. 1-7.

The horizontal gas flow electrostatic precipitator shown in FIG. In this housing 1 vertical flat dust collection poles 2 are arranged at equal intervals parallel to the main axis of the housing 1 and each extend over substantially the entire effective height corresponding to the length of the chord of the circle. There is. Disposed between the dust collecting electrodes 2 is a discharge electrode 3 stretched over a frame I5. Furthermore, this electrostatic precipitator has a scraper 6 which is pivotable about the axis of the housing on the lower region of the wall 5 of the housing that is provided with the dust outlet opening 4 . The cylindrical housing l is connected to a tubular inlet part 7, which inlet part has three conical parts a, b
At least 1 of the cross-sectional area of the gas supply section by Xc
It expands to the cross-sectional area of the cylindrical housing 1 which is 0 times the size, and has three gas distribution perforated plates 8a to 8 in the middle conical part.
It has c. Furthermore, the cylindrical housing 1 has a tubular outlet 9, which exits from the cross-sectional area of the cylindrical housing 1 by three conical portions C1b, a at most its l/
The cross section of the gas outlet has a size of 10 ++1. The tubular inlet portion 7 is provided with a pressure relief damper 10 . A mechanical conveyor 12 is located below the housing 1.
and a crossbar 13 separating the dust outlet openings 4 from each other on the gas side (see also FIG. 3). A discharge electrode 3 is stretched on a frame 15 and attached to the housing 1 via a support 17 and an insulator 16. Scraper 6 is crossbar 1
It is rotatably attached to 8.

An annular lip 20 is further provided to strengthen the housing 1.

As best seen in FIG. 2, the scraper 6 is rotatably mounted on a crossbar 18 and can be moved over the lower area of the wall 5 of the housing provided with the dust evacuation opening. A grounded dust collection electrode 2 is suspended directly within the housing 1, and a discharge electrode 3, which is stretched around a frame and to which a high voltage is applied, is supported via a support 17 and an insulator 16. The housing 1, reinforced with ribs 20, rests on the foundation via struts 19.

From FIG. 3 one can clearly see the dust outlet opening 4, which is arranged in the lower part of the housing 1, which together with the tubular inlet part 7 and the tubular outlet part 9 defines the outer shape of the electrostatic precipitator. . FIG. 3a, which is a sectional view taken along the line a-a'd in FIG. 3, shows a simplified representation of the conveyor 12 disposed within the dust collection duct 11.

This conveyor essentially consists of a circulating endless chain 22, to which is fixed a scraper 21 which extends transversely to the conveying direction. The chain is attached to laterally arranged bars 23 and is moved by drive means (not shown). The dust sent downward through the dust discharge opening 4 is removed by a scraper 2 fixed to a chain 22.
1 to the right and finally discharged from the dust collection duct (not shown). A crossbar 13 is further provided in the dust holding duct between the upper and lower courses of the chain, and this crossbar acts together with the dust filling and scraper 21 of the dust holding duct to open the dust discharge opening 4 on the gas side. separate them from each other. Figure 4A
The gas distribution plate 8 shown in FIG. 8 has a series of compartments 14, each compartment being maintained in a vertical position against a stop member by normal gas flow, but in the event of a sudden pressure increase in the electrostatic precipitator. It is swingably suspended in such a way that it can swing in a direction opposite to the flow direction and thus rapidly lowers the pressure (see FIG. 4B).

FIG. 5 shows a preferred structure of the gas passage openings in the gas distribution perforated plate.

In FIG. 6 a precipitator with a housing 1, a tubular inlet 7 and a tubular outlet 9 is shown again in a simplified manner, the diameter d and the height h of the individual conical sections being determined according to the purposes of the invention. It is clearly shown how things are changing. From Figure 6,
The tubular inlet part 7 and the tubular outlet part 9 are d1 to d3 and h1.
It will be appreciated that .about.h3 may be substantially the same within the relationships described above for the diameter of the housing l.

FIG. 7 again schematically shows the arrangement of the gas distribution perforated plates 8a to 8C within the intermediate portion of the tubular inlet. According to this, the gas distribution holes +Ii 8a and 80 are arranged at the minimum and maximum diameter positions of this intermediate portion, respectively, while the gas distribution perforated plate 8b is arranged so that each gas distribution perforated plate is equally spaced in the gas flow direction. Gas distribution perforated plate 8 so as to be present at intervals
It is located exactly between a and 8C.

The electrostatic precipitator of the invention not only provides a structurally optimal solution with respect to the specific functions mentioned at the outset, but also provides a tubular inlet and a tubular outlet, which can be very expensive, especially in the case of large diameters. can be manufactured very economically.

For this purpose, plain cedar boards are often proposed, but their manufacture requires correspondingly large processing equipment, and their circular shape is not advantageous with respect to gas guidance.

In contrast, the conical part proposed by the invention can be manufactured to virtually any diameter using individual sheet metal blanks which are slightly deformed if necessary and are joined by explosive welding.

The invention can be summarized as follows.

An electrostatic precipitator for horizontal gas flow has been proposed, in which vertical flat collecting electrodes are arranged in a cylindrical pressure-tight housing at equal intervals parallel to the main axis of the housing and each has a chord of a circle. Corresponding to the length, a discharge electrode extending over the entire effective height is arranged between the collecting electrodes, which is stretched over a frame, and a lower part of the wall of the housing with a dust discharge opening is arranged between the collecting electrodes. It has a scraper that is swingable about the axis of the housing over the region. In order to avoid dust fluidization and flow stagnation spaces, three conical sections extend from the cross-sectional area of the gas supply to a cross-sectional area of the cylindrical housing that is at least 10 times larger; A tubular inlet section with three gas distribution perforated plates has been proposed.

〔Effect of the invention〕

As stated above, the electrostatic precipitator of the present invention not only meets the requirements for a cylindrical housing, but also does not form accumulated dust that is fluidized in an uncontrolled manner in the gas flow and does not create flow stagnation spaces.

Moreover, the design can be manufactured in all desired dimensions at a significantly greater cost than previously.

[Brief explanation of the drawing]

1 to 7 show embodiments of the electrostatic precipitator of the present invention.
Figure 2 is a vertical cross-sectional view, Figure 3 is a partially sectional plan view, Figure 3a is a detailed view of the dust evacuation means area, Figure 4 A and B are gas Fig. 5 is an enlarged view showing the details of the gas distribution perforated plate, Fig. 6 is a diagram showing the detailed structure of the tubular inlet section, and Fig. 7 is a diagram showing the detailed structure of the gas distribution perforated plate. It is a figure showing arrangement. In addition, in the symbols used in the drawings, 1.
−−−−−−・−・−・Collecting electrode 3・・−11−−−
−−−−−−−−−−−Discharge electrode 4−−−−−−・−・−
---1----Dust discharge opening 5--------・-・・・
・−・−Housing wall 6−・−1−−−−−−−
-・------Scraper 7--・---・--1-----Tubular inlet portion 8a to 8c--Gas distribution perforated plate a"-c...-1---- --It is a conical part.

Claims (1)

[Claims] 1. An electrostatic precipitator for horizontal gas flow, in which vertical flat dust collecting electrodes are arranged at equal intervals in parallel to the main axis of the housing in a cylindrical pressure-resistant housing, and each extending over substantially the entire effective height corresponding to the length of the chord of the circle;
A discharge electrode stretched on a frame is disposed between the dust collection electrodes, and has a scraper that is swingable about the axis of the housing on a lower area of the wall of the housing that is provided with a dust discharge opening. An electrostatic precipitator having a tubular inlet part,
The inlet section extends by three conical sections from the cross-sectional area of the gas supply section to a cross-sectional area of the cylindrical housing that is at least 10 times larger than the cross-sectional area of the gas supply section and has three gas distribution perforated plates in the intermediate conical section. An electric precipitator featuring: 2. It has a tubular outlet section, which outlet section extends up to 1/2 of the cross-sectional area of the cylindrical housing by means of three conical sections.
The electrostatic precipitator according to claim 1, characterized in that the cross-sectional area of the gas outlet is narrowed down to a size of 10 mm. 3. Claim 1, characterized in that the tubular inlet section has one or more spring-loaded dampers for pressure relief.
The electrostatic precipitator according to item 1 or 2. 4. The smaller diameter d of each conical portion of the tubular inlet and outlet has the following relationship with the housing diameter D: 0.24D≦d_3≦0.36D (preferably 0.3D
), 0.36D≦d_2≦0.48D (preferably 0.
42D), 0.90D≦d_1≦0.95D (preferably 0.925D), the electrostatic precipitator according to any one of claims 1 to 3. . 5. Height h of each conical part of the tubular inlet and outlet
is the housing diameter D and the following relationship: 0.075D≦h_
3≦0.135D (preferably 0.105D), 0.1
20D≦h_2≦0.200D (preferably 0.160
D), the electrostatic precipitator according to any one of claims 1 to 4, wherein the relationship is 0.045D≦h_1≦0.075D (preferably 0.060D). vessel. 6. The gas distribution perforated plate provided on the surface of diameter d_2 is 52
~60%, preferably 56% open pore area, the other two gas distribution perforated plates 54~62%, preferably 5
The electrostatic precipitator according to any one of claims 1 to 5, having an open pore area of 8%. 7. A closed dust collection duct having a mechanical conveyor and a crossbar separating the dust discharge openings from each other on the gas side is arranged below the dust discharge openings. The electrostatic precipitator according to any one of Items 1 to 6. 8. The electrical collector according to any one of claims 1 to 7, wherein the gas perforated plate has a movable suspended portion that swings in a direction opposite to the gas flow direction. Dust container.