JPH0221864B2 - - 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. and extending vertically over substantially the entire effective height, each corresponding to the length of the chord of the circle, and disposed between the collecting electrodes is a discharge electrode stretched on a frame, , 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.
By providing three gas distribution perforated plates having a specific cross-sectional area relationship at the tubular inlet, it is possible to obtain a dust collector in which neither dust accumulated in the gas flow nor flow stagnation space is formed. It is.

[Problems to be solved by conventional technology and invention]

A precipitator of this type is known from German patent no. The requirement to eliminate flow stagnation spaces in view of the risk of explosion in the case of alternating feeds is substantially met. Nevertheless, failures still occasionally occurred due to deflagration 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 permanently or temporarily explosive gas mixtures. for example,
The flue gas from blast furnaces operating under an overpressure of 1.5-2.5 bar is dedusted in this way to depressurize the turbine to an overpressure of 40-80 mbar in order to recover energy without risk of erosion. be done.
For this purpose, the dust content must be reduced to 5-20 mg/m ³ beforehand. To maximize the available pressure drop, only electrostatic precipitators with a pressure drop of 1 to 2 mbar are considered. This is because high-power scrubbers with comparable separation performance have pressure losses of 200 to 400 mbar.

Another field of application for precipitators of this kind is in coal crushing plants, the exhaust gas of which can be explosive within certain limits due to its 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 dust removal, combustible gases are collected in containers or sent to the gas supply system, while gases generated intermediately in addition to the original blowing of the converter are removed and released into the atmosphere from the chimney. is released. 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 stream, which can cause pressure fluctuations in the precipitator or in the dust system located upstream. Adhering dust 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.

In precipitators for converter flue gases, if a sudden infiltration of air occurs during a critical period, or if the flow stagnates due to a design flaw, a certain amount of gas with an uncertain composition may accumulate. Deflagration can occur if parts of the fluid system that are in contact are reactivated by transient pressure fluctuations. 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.

Therefore, the object of the present invention is to improve existing precipitators so that they not only meet the requirements in the cylindrical part, but also eliminate the accumulation of dust that is fluidized in an uncontrolled manner in the gas flow and the flow stagnation spaces. It is an object of the present invention to provide an electrostatic precipitator that is entirely designed to prevent the formation of dust. Moreover, the design must be as economical as possible to implement for all required dimensions.

[Means for solving problems]

All the above requirements are fulfilled by the fact that the three conical sections extend from the cross-sectional area of the gas supply to the cross-sectional area of the cylindrical housing that is at least 10 times larger and that the three gas distributions in the intermediate conical section It has surprisingly been found that filling is achieved particularly effectively by providing a tubular inlet with a perforated plate.

Furthermore, it is proposed to provide a tubular outlet which is constricted by three conical sections from the cross-sectional area of the cylindrical housing to a cross-sectional area of the gas outlet that is at most 1/10 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 flows and gas distributions are obtained in the electrostatic precipitator of the 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 housing diameter D. Relationship: 0.24D≦ _d3 ≦0.36D (preferably 0.3D), 0.36D≦ _d2 ≦0.48D (preferably 0.42D), 0.90D≦ _d1 ≦0.95D (preferably 0.925D), and tubular The height h of each conical section of the inlet and tubular outlet has the following relationship to the diameter D of the housing: 0.075D≦h ₃ ≦0.135D (preferably 0.105D), 0.120D≦h ₂ ≦0.200D (preferably 0.160D), 0.045D≦h ₁ ≦0.075D (preferably 0.060D).

A gas distribution perforated plate provided on a surface with a diameter d ₂ is 52~
It has an open area of 60%, preferably 56%, and the other two gas distribution perforated plates have an open area of 54-62%, preferably
It is desirable to have an open pore area of 58%. moreover,
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〕

Details and advantages of the electrostatic precipitator of the present invention are described in Parts 1 to 7.
The embodiments shown in the figures will be explained in more detail below.

The horizontal gas flow electrostatic precipitator shown in FIG. In this housing 1, vertical flat dust collecting electrodes 2 are arranged at regular intervals parallel to the main axis of the housing 1 and each corresponds to the length of a chord of a circle and extends over substantially the entire effective height. It is extending. Disposed between the dust collecting electrodes 2 is a discharge electrode 3 stretched on a frame 15. 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 evacuation opening 4 . The cylindrical housing 1 is connected to a tubular inlet part 7 which, by means of three conical parts a, b, c, is at least ten times larger than the cross-sectional area of the gas supply part. It extends to the cross-sectional area and has three gas distribution perforated plates 8a to 8c in the middle conical part b. Furthermore, the cylindrical housing 1 has a tubular outlet part 9, which has three conical parts c,
By b and a, the cross-sectional area of the cylindrical housing 1 is narrowed down to the cross-sectional area of the gas outlet, which is at most 1/10 of the cross-sectional area of the cylindrical housing 1. The tubular inlet portion 7 is provided with a pressure relief damper 10 . Below the housing 1 there is a mechanical conveyor 12 and a dust discharge opening 4.
A closed dust collection duct 11 extends (see also FIG. 3) with a crossbar 13 separating the two from each other on the gas side. A discharge electrode 3 is stretched on a frame 15 and attached to the housing 1 via a support 17 and an insulator 16. A scraper 6 is rotatably attached to the crossbar 18. An annular rib 20 is additionally provided to strengthen the housing 1.

As can best be seen in FIG. 2, the scraper 6 is rotatably mounted on a crossbar 18 and can be swung over the lower region of the housing wall 5 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 it can be clearly seen that the dust outlet opening 4 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. ing. FIG. 3a, which is a sectional view taken along line a-a in FIG.
2 is illustrated in a simplified manner. This conveyor essentially consists of a circulating endless chain 22, to which is fixed a scraper 21 extending transversely to the conveying direction. The chain is attached to laterally arranged bars 23 and is moved by drive means (not shown). Dust discharge opening 4
The dust sent downward through the chain 22 is sent to the right by a scraper 21 fixed to a chain 22, and finally discharged from a 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, which acts together with the dust filling and scraper 21 of the dust holding duct to keep the dust outlet opening 4 on the gas side. separate them from each other. The gas distribution plate 8 shown in FIG. 4A has a series of sections 14, each section being maintained in a vertical position against a stop member by normal gas flow.
It is swingably suspended in such a way that it can swing in a direction opposite to the gas flow direction in the event of a sudden pressure increase in the electrostatic precipitator, thus quickly reducing the pressure. (See Figure 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 FIG. 6, it can be seen that the tubular inlet section 7 and the tubular outlet section 9 have d ₁ to d ₃ and h ₁ to h ₃ in the housing 1.
It can be seen that within the range of the above-mentioned relationships, the diameter D may be substantially the same.

FIG. 7 again schematically shows the arrangement of the gas distribution perforated plates 8a to 8c in the intermediate portion b of the tubular inlet. According to this, the gas distribution perforated plates 8a and 8c are arranged at the positions of the minimum diameter and the maximum diameter of this intermediate portion b, respectively, while the gas distribution perforated plate 8b
is located exactly between the gas distribution perforated plates 8a and 8c so that each gas distribution perforated plate exists at equal intervals in the gas flow direction.

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, countersunk plates 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 joined by 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. a lower region of the wall of the housing, which extends over substantially the entire effective height and is arranged between said collecting electrodes and is stretched over a frame, in the wall of the housing; It has a scraper that can swing around the axis of the housing at the top. 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 in the shaped part is proposed.

〔Effect of the invention〕

As stated above, the electrostatic precipitator of the present invention not only satisfies the requirements for a cylindrical housing, but also
No accumulated dust is formed which is fluidized in an uncontrolled manner in the gas flow, and no flow stagnation spaces are formed.
Moreover, the design can be manufactured in all desired dimensions at a significantly greater cost than previously.

[Brief explanation of drawings]

Figures 1 to 7 show examples of the electrostatic precipitator of the present invention, in which Figure 1 is a vertical longitudinal cross-sectional view, Figure 2 is a vertical cross-sectional view, and Figure 3 is a partially sectional plan view. , 3rd a.
The figure is a detailed view of the dust evacuation means area, Figures 4A and B are plan and side views of the gas distribution perforated plate, respectively, Figure 5 is an enlarged view showing details of the gas distribution perforated plate, and Figure 6 is the tubular inlet. A diagram showing the detailed structure of the part,
FIG. 7 is a diagram showing the arrangement of the gas distribution perforated plate. In addition, in the symbols used in the drawings, 1...housing, 2...dust collection electrode, 3...discharge electrode, 4...dust discharge opening, 5...housing wall, 6...scraper, 7...tubular Entrance section, 8a-8c...
Gas distribution porous plates, a to c... conical portions.

Claims (1)

[Scope of Claims] 1. An electrostatic precipitator for horizontal gas flow, in which vertical flat-plate dust collecting electrodes are arranged at equal intervals parallel to the main axis of the housing in a cylindrical pressure-resistant housing, and each has a circular shape. A discharge electrode extending over substantially the entire effective height, corresponding to the length of the chord of the frame, is disposed between the collecting electrodes and is attached to a frame, which opens the dust discharge opening in the wall of the housing. An electrostatic precipitator comprising a scraper which is swingable about the axis of the housing on a lower region provided with a tubular inlet, which inlet is connected to a gas supply by means of three conical sections. , extending from the cross-sectional area of the cylindrical housing to a cross-sectional area of the cylindrical housing at least ten times as large as the cross-sectional area of the electrostatic precipitator, characterized in that it has three gas distribution perforated plates in an intermediate conical part. 2. It has a tubular outlet section, and the outlet section is narrowed by three conical sections to a cross-sectional area of the gas outlet that is at most 1/10 of the cross-sectional area of the cylindrical housing. Claim 1:
Electrostatic precipitator as described in section. 3. The electrostatic precipitator according to claim 1 or 2, characterized in that the tubular inlet section has one or more spring-loaded dampers for pressure relief. 4 The smaller diameter d of each conical portion of the tubular inlet and tubular outlet is the diameter D of the housing.
and the following relationships: 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), Claims 1 to 3 are characterized in that:
The electrostatic precipitator according to any one of paragraph 3. 5. The height h of each conical portion of the tubular inlet and outlet has the following relationship with the housing diameter D: 0.075D≦h ₃ ≦0.135D (preferably 0.105D), 0.120D≦h ₂ ≦0.200D (preferably 0.160D), 0.045D≦h ₁ ≦0.075D (preferably 0.060D). Electric precipitator. 6 A gas distribution perforated plate provided on a surface with a diameter d ₂ is 52
Claims characterized in that it has an open pore area of ~60%, preferably 56%, and the other two gas distribution perforated plates have an open pore area of 54-62%, preferably 58%. The electrostatic precipitator according to any one of Items 1 to 5. 7. Claim 1, characterized in that a closed dust collection duct with 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 6 to 6. 8. The electrostatic precipitator 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. vessel.