DE202017003859U1 - Earthing system for wet electrostatic precipitators - Google Patents

Abstract

Grounding system (20, 30), in particular for wet electrostatic precipitators (1) for the separation of sulfur oxides and dusts from exhaust gases, comprising at least a plurality of precipitation tubes (2) which are accommodated in a carrier element and via a respective earthing system (20, 30) at the top and bottom End electrically conductively connected to each other, characterized in that at least one grounding system (20, 30) consists of a conductive fiber composite material with a carbon content.

Description

The invention relates to a grounding system, in particular for wet electrostatic precipitators for the deposition of sulfur oxides and dusts from exhaust gases, comprising at least a plurality of precipitation tubes, which are accommodated in a support member and electrically connected to each other via a respective grounding system at the top and bottom.

In order to carry out an exhaust gas purification, wet electrostatic precipitators are used, which are used, for example, in flue gas systems, in order to allow deposition of sulfur oxides and dusts from the exhaust gases. In this case, the wet electrostatic filters consist of a bundle of preferably a plurality of plastic pipes as precipitation pipes, which are held by suitable carrying collars and guide rings. In the middle of each tube extends an electrode, wherein in the operation of the filter, the inner walls of the tubes are wetted with a flowing electrically conductive washing liquid. The pipes themselves are earthed, so that a strong electric field can be formed between the electrode and the wall of the pipe. By the electric field, an ionization of the exhaust gases is achieved, so that they are electrically charged and following the electric field lines to migrate to the tube walls. From the tube walls, the charged exhaust gas particles are taken up by the washing liquid and transported to the outside via the lower tube ends. Due to the high electric field, it is imperative that the pipes are earthed to avoid electrical breakdown.

The precipitation pipes are exposed to strong temperature fluctuations, so that the associated length contraction must be taken into account. For this reason, the precipitation pipes are taken with their upper end in the support collars and arranged vertically hanging. Distributed over the length of the precipitation tubes guide rings are arranged, which stabilize the tubes in their position. In contrast, the lower end of the precipitation tubes is received free-hanging, so that a length expansion can be taken into account. At the top and bottom of the precipitation pipes are grounded, and due to the suspension in the upper area no dynamics of the precipitation tubes is to be expected and thus a very stable grounding system can be used. In contrast, at the lower ends of the precipitation pipes, a flexible earthing system must be used, which takes into account the change in length of the precipitation pipes.

From the prior art, it is known to use, for example, a sandwich structure for a grounding system, which consists of an upper and lower plastic plate, between which a graphite layer is incorporated. In practical use, it has unfortunately been shown that this graphite layer is attacked by the sulfur oxides in the flue gases and causes the graphite layer to be inflated. With the growth of the graphite layer, precipitates of the vapors, in particular of the sulfur oxides in the graphite can deposit and lead to further destruction of the graphite layer. In addition, the desired low resistance value of the graphite layer is adversely affected.

From the DE 41 02 732 A1 Niederschlagrohrbündel are known in which the individual tubes are glued together on their outer walls and each tube is bordered at its two ends from the outside by an electrically conductive tape as a grounding conductor. In the wall of the tube below the conductive band through holes are arranged, which connect the conductive tape with the pipe inside. A disadvantage has been found that an interchangeability of the individual tubes is not given, or can be carried out only with high labor input.

From the DE 198 33 226 A1 Also, a precipitation tube bundle for wet electrostatic precipitators is known in which the tube earthing in each precipitation tube, an upper grounding as inner grounding and a lower ground, which is welded in the surface of the precipitation tube present. The individual grounding points of the pipes are electrically connected to each other. For example, the inner ground consists of a polypropylene injection-molded ring with four graphite inserts and a graphite foil jacket, while the lower ground consists of a carbon cord or a carbon tube. In practical use, however, has shown that the interchangeability of the precipitation pipes is not feasible to the desired extent. In bonded honeycomb bundles replacement is not feasible and only limited possible with welded honeycomb bundles.

The present invention has for its object to show a homogeneously constructed grounding system, which has chemical resistance to sulfur oxides and other pollutants contained in the exhaust gases.

According to the invention, it is provided for the solution that at least one grounding system consists of a conductive fiber composite material with a carbon content.

By using a conductive fiber composite material with a carbon content on the one hand, a high chemical resistance can be achieved, on the other hand, the fiber composite material has a high strength and high conductivity. This can be done using the fiber composite material, the grounding of the wet electrostatic precipitator and possible destruction of the fiber composite material by the existing exhaust gases, especially sulfur oxides can be excluded. Thus, the known from the prior art disadvantages are eliminated and ensures a long life of the grounding system.

The fiber composite materials are made of carbon fiber reinforced carbon, which has a high stability as well as temperature and chemical resistance. Carbon fiber products in the form of multiaxial layers based on glass fibers or carbon can be used, among other things, which lead to high strength with carbon and a composite material. As far as multiaxial scrims made of carbon fibers, optionally glass fibers are used, this can be carried out here uniaxial, biaxial, triaxial or quadroxial, with the different clutches differ only by the number of layers. Particularly noteworthy here is the resistance to aggressive media.

To solve the invention task is further provided that at least one grounding system consists of a fiber composite material with carbon content, in which annular breakthroughs are incorporated for the precipitation tubes. A first embodiment of the grounding system is that the grounding system is plate-shaped and consists of an electrode plate made of fiber composite with carbon content. The electrode plate is in this case equipped with a plurality of annular openings through which the precipitation tubes protrude. Thus, via the grounded electrode plate is a connection to the non-conductive precipitation tubes and the electrically conductive washing liquid. The case required strong electric field is built up between the running in the precipitation tubes electrode and the washing liquid. This type of grounding system is suitable here in the form of an electrode plate for the upper region of the precipitation pipes and can be placed, for example, on a used carrying sleeve, which is usually made of plastic. By appropriate screwing with the support cuff the required stability is achieved.

Alternatively, it is provided to solve the task that at least one grounding system consists of individual grounding elements, which are arranged around the individual rainwater pipes electrically connected via contact means, wherein the grounding elements consist of a conductive fiber composite material with a carbon content. Instead of an electrode plate, individual grounding elements can be used, which are arranged around the individual precipitation tubes, for example three or six grounding elements, which are electrically conductively connected to one another via contact means. The earthing elements themselves also consist of a conductive fiber composite material with a carbon content, so that the required earthing of the rainwater pipes is ensured. Also in this case, the washing liquid is passed over the grounding elements and the inner walls of the precipitation tubes, so that a strong electric field between the washing liquid and the centrally arranged electrode can be constructed. Such a grounding system can preferably be used at the lower end of the precipitation tubes, because the individual grounding elements allow a movement against each other, so that there is sufficient elasticity of the grounding system.

As a further alternative solution of the problem is provided that at least one grounding system consists of individual grounding elements made of a fiber composite material with carbon, which are electrically conductively connected to each other via a conductive foil or contact layer. This preferred embodiment provides that also individual grounding elements are used made of a fiber composite material with carbon, but these are directly in contact with a conductive foil or contact layer. The conductive film or contact layer may also consist of a fiber composite material with carbon content and have a significantly smaller thickness, so that a sufficient elasticity is present. Such a grounding system can be used both for the upper part of the downpipes and for the lower part of the downpipes.

Further advantageous embodiments of the invention will become apparent from the dependent claims.

The individual grounding elements are in this case formed substantially triangular and come to rest between the precipitation pipes. For this purpose, the grounding elements have three concave surfaces adapted to the diameter of the precipitation tubes, which are arranged offset from each other by 120 degrees. Thus, the grounding elements can be used both around individual downpipes and in a precipitation bundle of tubes between the downpipes. A single earthing element can in this case have direct contact with a precipitation tube, but also with two or three produce adjacent rainwater pipes. Through the concave surfaces in this case as large as possible contact with the precipitation pipes is made and thus further ensured that the washing liquid can drain via the grounding elements in the precipitation pipes. The washing liquid may be, for example, a spray or a sprayed washing liquid.

To increase the strength can be further provided that the grounding elements are connected to a support plate, preferably screwed. Such a support plate, which can also be referred to as a support sleeve, has a plurality of holes in which the individual precipitation tubes are received. If no individual grounding elements can be used, it is possible here to resort to a continuous electrode plate made of the same material, which is arranged above the carrier plate and, for example, terminates flush with the precipitation tubes.

To connect the individual grounding elements to ensure adequate grounding for the downpipes, they can be interconnected by an electrically conductive cover plate, which comes to rest on the outer side surfaces of the grounding elements. Alternatively, there is the possibility that connectable cable bridges or contact bridges are used as contact means with the grounding elements, which interconnect, for example, the immediately adjacent grounding elements. In such a case, it is possible either three or possibly six grounding elements to arrange a precipitation tube. Depending on the position of the individual earthing elements within the precipitation tube bundles, these may come into contact with a single precipitation tube, but also at least with two or three adjacent precipitation tubes.

A particularly preferred embodiment of the grounding system provides that the individual grounding elements are connected to one another by means of a conductive foil or contact layer. The conductive film or contact layer may also consist of a fiber composite material with a carbon content. In order to achieve the elasticity in this case, for example, a conductive foil in a thickness of 0.3 to 0.6 mm are used, in contrast, the individual grounding elements may have a thickness of 3-6 mm. Due to the elasticity of the conductive film or contact layer and the mutually movable grounding elements, the earthing elements are not mechanically connected to one another, but only via the conductive foil or contact layer, sufficient flexibility is required for such a system to be used at the lower end of the precipitation tubes for earthing , However, it is readily possible to use this system also at the upper end of the precipitation pipes.

The particular advantage of the present invention is that an acid-resistant fiber composite material is used, which has a high chemical resistance and is not attacked by sulfur oxides, for example. As a result, contact problems of the grounding system are avoided in wet electrostatic precipitators and ensure a long service life. In addition, by appropriate combination or shaping of the fiber composites either high stability can be achieved at the same time or by the division into many individual grounding elements elasticity can be achieved, which is required for the precipitation tubes at least in the lower area due to the effects of temperature by the flue gases.

The invention will be described again with reference to the figures.

It shows

1 a top view of a wet electrostatic precipitator with a precipitation tube bundle,

2 a partially sectioned side view of a single precipitation tube in a first embodiment,

3 a partially sectioned side view of a precipitation tube in a second embodiment,

4 a section along the connecting line AA and

5 in a plan view and side view of a single grounding element.

1 shows a partial view of a wet electrostatic precipitator 1 , which with a variety of precipitation pipes 2 Is provided. The rainwater pipes 2 are in a support plate 3 hooked up and be with the support plate 3 welded, so the rainwater pipes 2 can be fixed by the action of temperature in the upper area. Due to a possible length extension of the precipitation tubes 2 These are below the support plate 3 via guide rings only guided axially movable.

At the top of the precipitation pipes 2 is a grounding element 4 provided, which out individual earthing elements 5 and a grounding foil 6 consists. About a contact surface 7 the connection is made with the earthing foil 6 and thus also with the earthing elements 4 , The earthing elements 4 are each about six pieces around a single precipitation pipe 2 arranged so that, except in the edge region of each grounding element 4 Contact to three rainwater pipes 2 has. The individual earthing elements 4 be by screws 8th with the support plate 3 bolted so that the necessary cohesion in the upper part of the precipitation pipes 2 given is. Instead of the individual earthing elements 4 could also be used a grounding plate, which with corresponding cutouts for the precipitation tubes 2 is provided. In addition, there is the possibility of only three individual grounding elements 4 use that does not have a grounding foil 6 , but are connected to each other via cable bridges or the like.

2 shows in a partially sectioned side view a section of a wet electrostatic precipitator 1 with a single rainwater pipe 2 , The precipitation pipe 2 is in a support plate 3 taken up and with this over welds 10 welded. Below the upper support plate 3 is a second support plate 11 provided, which also has cross bracing 12 with the upper support plate 3 and with the downpipes 2 is welded. Over the entire length of the precipitation tube 2 are spaced guide elements 13 provided, which indeed with each other via a connecting element 14 are connected, but only one attachment to the second support plate 11 exhibit. The rainwater pipes 2 be in these guiding elements 13 only guided and are not firmly connected to these, so a change in length of the precipitation tubes 2 as a result of heating by the flue gases is possible.

The lower end of the precipitation pipes 2 has two guide plates 15 . 16 on that over a bolt 17 are bolted together and also to guide the precipitation pipes 2 are provided.

Both the lower and the upper end of the precipitation tubes 2 is with a grounding system 20 equipped, which in the embodiment shown from individual grounding elements 4 and a grounding foil 6 consists. The earthing elements 4 are over bolts 8th with the support plate 3 connected. The individual earthing elements 4 with the grounding foil 6 form at the top of the precipitation pipes 2 the grounding system 20 , wherein by sprinkling with a washing solution not only the grounding elements 4 but also the inner wall 9 the precipitation pipes 2 is wetted and in connection with a centrally mounted electrode by applying a voltage, a high electric field can be generated.

At the bottom is a similar construction with individual grounding elements 4 and a grounding foil 6 provided, this with the lower guide plate 16 by screwing 18 are connected. Thus, the precipitation pipes 2 Both grounded at the top and at the bottom.

3 shows a nearly identical construction of a wet electrostatic precipitator 1 with a single rainwater pipe 2 as it already is from the 2 is known. The grounding system 30 consists in this case of a continuous grounding plate 31 , which has been made for example of a fiber composite material with carbon content. This grounding plate 31 is chemically resistant to the sulfur oxides or other pollutants contained in the flue gases and can directly on the support plate 3 be hung up. A screw connection is done with bolts 32 , So that the precipitation pipes 2 open at the top, must have corresponding holes in the grounding plate 31 to be available.

4 shows in a cut-out enlargement along the connecting line AA a section through the grounding system 20 consisting of a single grounding element 4 and a grounding foil 6 , The two rainwater pipes 2 are here in the support plate 3 mounted and connected by a weld.

5 shows in a side view and plan view of a single grounding element 4 , which was made of a carbon fiber composite material. The earthing element 4 may in this case have a thickness of about 3 to 6 mm and is approximately triangular shaped, each offset by 120 degrees concave curves 35 . 36 . 37 to the diameter of the precipitation pipes 2 are adapted so that a single grounding element 4 directly to at least one, preferably two or three precipitation pipes 2 can be created. The individual earthing elements 4 thus fill the gaps between the precipitation pipes 2 and are further connected by cable connections or contact foils, so that a grounding of the precipitation tubes 2 is guaranteed. The individual earthing elements 4 have a hole in the middle 38 on, through which a screw with the support plate 3 can be done.

LIST OF REFERENCE NUMBERS

1

Wet Electrostatic Precipitator

2

Precipitation tube

3

support plate

4

grounding element

5

grounding element

6

ground sheet

7

contact area

8th

screw

9

inner wall

10

Weld

11

support plate

12

cross brace

13

guide element

14

connecting element

15

guide plate

16

guide plate

17

bolts

18

screw

20

grounding system

30

grounding system

31

ground plate

32

bolts

35

curve

36

curve

37

curve

38

drilling

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4102732 A1 [0005]
• DE 19833226 A1 [0006]

Claims (13)

Grounding system ( 20 . 30 ), in particular for wet electrostatic precipitators ( 1 ) for the separation of sulfur oxides and dusts from exhaust gases, comprising at least several rainwater pipes ( 2 ), which are accommodated in a carrier element and in each case via a grounding system ( 20 . 30 ) are electrically conductively connected to one another at the upper and lower ends, characterized in that at least one grounding system ( 20 . 30 ) consists of a conductive fiber composite material with a carbon content. Grounding system ( 20 . 30 ), in particular for wet electrostatic precipitators ( 1 ) for the separation of sulfur oxides and dusts from exhaust gases, comprising at least several rainwater pipes ( 2 ), which are accommodated in a carrier element and in each case via a grounding system ( 20 . 30 ) are electrically conductively connected to one another at the upper and lower ends, characterized in that at least one grounding system ( 20 . 30 ) consists of a fiber composite material with carbon content, in which annular breakthroughs for the precipitation tubes ( 2 ) are incorporated. Grounding system ( 20 . 30 ), in particular for wet electrostatic precipitators ( 1 ) for the separation of sulfur oxides and dusts from exhaust gases, comprising at least several rainwater pipes ( 2 ), which are accommodated in a carrier element and in each case via a grounding system ( 20 . 30 ) are electrically conductively connected to one another at the upper and lower ends, characterized in that at least one grounding system ( 20 . 30 ) from individual earthing elements ( 4 . 5 ), which around the individual rainwater pipes ( 2 ) are arranged electrically conductively connected to each other via contact means, wherein the grounding elements ( 4 . 5 ) consist of a conductive fiber composite material with a carbon content. Grounding system ( 20 . 30 ), in particular for wet electrostatic precipitators ( 1 ) for the separation of sulfur oxides and dusts from exhaust gases, comprising at least several rainwater pipes ( 2 ), which are accommodated in a carrier element and in each case via a grounding system ( 20 . 30 ) are electrically conductively connected to one another at the upper and lower ends, characterized in that at least one grounding system ( 20 . 30 ) from individual earthing elements ( 4 . 5 ) consists of a fiber composite material with carbon content, which are electrically conductively connected to each other via a conductive foil or contact layer. Grounding system ( 20 . 30 ) according to one of claims 1, 3 or 4, characterized in that the grounding elements ( 4 . 5 ) are formed substantially triangular. Grounding system ( 20 . 30 ) according to one of claims 1, 3 or 4, characterized in that the grounding elements ( 4 . 5 ) three to the diameter of the precipitation tube ( 2 ) has adapted concave surfaces, which are arranged offset by 120 degrees to each other. Grounding system ( 20 . 30 ) according to one of claims 1, 3 or 4, characterized in that the grounding elements ( 4 . 5 ) are preferably bolted to a support plate. Grounding system ( 20 . 30 ) according to one of claims 1, 3 or 4, characterized in that in each case three or six grounding elements ( 4 . 5 ) around a precipitation pipe ( 2 ) are arranged. Grounding system ( 20 . 30 ) according to one of claims 1, 3 or 4, characterized in that the grounding elements ( 4 . 5 ) at least with two rainwater pipes ( 2 ) are in electrical connection. Grounding system ( 20 . 30 ) according to one of claims 1, 3 or 4, characterized in that a plurality of grounding elements ( 4 . 5 ) are interconnected by an electrically conductive cover plate which on the outer side surfaces of the grounding elements ( 4 . 5 ) comes to rest. Grounding system ( 20 . 30 ) according to one of claims 1, 3 or 4, characterized in that the cover plate consists of a carrier material and an elastically bonded carbon layer, wherein the carbon layer the grounding elements ( 4 . 5 ) faces the electrical contact. Grounding system ( 20 . 30 ) according to one of claims 1 to 11, characterized in that the precipitation pipes ( 2 ) consist of round tubes, which are assembled to a compact structure as possible. Grounding system ( 20 . 30 ) according to claim 3, characterized in that the contact means consist of connectable cable bridges or contact bridges.

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