EP1617143B1 - Grate bar with corresponding grate and incinerator - Google Patents

Abstract

The grill plate has an upper side (10), underside (12), two lengthwise sides (14,16) and two widthwise sides. On the side next to the first lengthwise side the plate has a device to attach to a support part (20). Underneath and next to the second lengthwise side is at least one flow channel (32),to which a section (16u) next to the underside (14) of the second lengthwise side is led along the area under the plate to an opening. A channel (40) conducting cooling fluid runs in a first section (10r) of the upper side. The combustion grate has several such grill plates.

Description

The invention relates to a grate plate for a combustion grate, a grate formed from grate plates and a waste incineration plant with such a combustion grate.

The most important component of a waste incineration plant is the combustion grate, which is arranged horizontally or inclined and on which the firing material, for example refuse, is conveyed from a first end to a second end, usually Ausbrandrost. The required combustion air is forced through the combustion grate. For this purpose corresponding openings are provided in the grate. In this way, the kiln (the residue) is essentially "dried" in three process steps, then "burned" and finally converted to slag. These three process steps can be controlled individually if required.

There are several types of combustion grates, including but not limited to the so-called booster combustion grate. Such a grate has moving parts (grate plates) which are suitable for carrying out scrubbing, whereby the kiln (the residue) is conveyed on the combustion grate. In this case, the individual grate plates, staggered in relation to each other in the region of their side facing the combustion chamber, lie on top of one another. If, for example, every second grate plate is movably arranged, it is achieved by the movement of this grate plate that the residue, which rests on the grate plate following in the transport direction, is transported on to the next grate plate.

In a combustion plant of the type mentioned different types of residues can be burned. Typical residuals are household waste, commercial waste, wood sawdust, waste wood, waste wood, processed fractions of various waste materials (RDF = refuse derived fuel), biomass, or the like, for example sewage sludge. The individual types of residue differ with regard to their calorific value. However, this also applies within the individual types of residues. For example, household waste may have a calorific value between 5 and 20 MJ / kg. Depending on this calorific value, the thermal and mechanical stress of the combustion grate or its grate plates changes.

In order to counteract this wear and tear, it is sufficient to cool the grate plates with air when burning residual materials with a calorific value of up to 10 MJ / kg. An air-cooled combustion grate describes the EP 0 391 146 A1. At an assumed temperature in the combustion chamber of 900 ° - 1,250 ° C and a temperature in the resting on the combustion grate furnace layer of> 800 ° C, the temperature of these air-cooled grate plates on their surface, for example 400 ° - 600 ° C,

In the combustion of fuel with a higher calorific value combustion grates are often preferred, the grate plates with a liquid, especially water, are cooled (EP 954 722 B1). However, the procedural outlay for water cooling is significantly higher than for air cooling. For certain combustion processes, the more intensive water cooling leads to undesirably intensive cooling of the grate plates, in which the temperature at the surface of the grate plates can be 90 ° -110 ° C., at a temperature in the firing layer (on the combustion grate) of, for example, 700 ° -800 ° ° C.

The outlined technologies and procedural parameters show that air- or water-cooled grate plates / combustion grates are two clearly defined systems. This also applies if, according to EP 954 722 B1, both systems are connected in series.

EP 0921354 A1 shows a liquid-cooled grate plate having an upper side, a lower side, two longitudinal sides and two broad sides, which has a device for connecting a support element adjacent to a first longitudinal side and in which a plurality of air nozzles are arranged below and next to the second longitudinal side. Air is guided from an area below the grate plate through these nozzles, which are arranged approximately at the center of the second longitudinal side. In the area of the first longitudinal side, a section of a coolant channel runs.

The object of the invention is to provide a way to make the known systems variable in terms of their application.

To solve this problem, the invention proceeds from the following considerations: Each grate plate is above all to the firebox, so in particular exposed at its top and front end, a particularly intense heat load. Primary air is directed against the underside of the grate plates, so it cools from below, and is forced through openings in the grate plates or between the grate plates in the lying on the grate plates Brenngutschicht. The heat-loaded part of each grate plate is on the underside of a certain cooling volume to dissipate the heat generated. However, especially in the edge region, the cooling is insufficient. Such areas, for example, the combustion chamber facing end side (longitudinal side) of a grate plate, are therefore particularly susceptible to corrosion and erosion.

A first approach provides in this context, the area below the top and next to the front side longitudinal side of the grate plate with at least one flow channel, along the air from below targeted against the top or the adjacent front longitudinal side is performed.

In this way, a type of air nozzle is formed, wherein the air with a correspondingly high flow velocity cools the critical front (the combustion chamber facing) portion of the respective grate plate "from below". This cooling is significantly higher than in a conventional cooling according to the prior art, but less than in a water cooling.

At the same time, this at least one flow channel is designed such that it has an air outlet opening on the portion of the corresponding end face (end face) adjacent to the underside, so that the air flow is then selectively directed to the surface of the grate plate following in the direction of transport of the material to be burned, and this surface likewise cools. Through this targeted air irradiation of the The adjacent grate plate has the further advantage that deposits observed there in the prior art can be largely avoided. Such deposits, also called Aufschweißungen arise in the case of combustion grates in the prior art, for example, by precipitation of metals from the kiln.

In the "rear" part of the grate plate runs in the first portion of the top (ie, between the first longitudinal side and the second portion of the top), a channel which is traversed by a cooling medium, such as a fluid and / or a gas.

Along this channel, a fluid cooling of the grate plate can be done, especially with water. In this embodiment, therefore, the "back" part of the grate plate is intensively cooled with a liquid, while the same plate (rust stage) is cooled in the front part (the firing and combustion chamber adjacent) with air, with increased cooling effect over a known air cooling.

As far as this is considered sufficient, however, the "front" grate plate part can also be cooled conventionally with air, for example, instead of the air cooling along the flow channel air is simply guided from below against the grate plate in this section.

Alternatively, the rear part of the grate plate can also be cooled by pushing a gas, in particular air, through the channel. This embodiment, with "double air cooling" in the front and rear part of the grate plate, is chosen when the cooling, especially in the rear part of the grate plate, needs to be less intense.

Depending on the material to be burned and the process conditions during combustion, it is also possible to switch over between air and water cooling in the first section of the grate plate, for which purpose the channel (the water line) is previously cleared with previous fluid cooling.

Thereafter, the invention relates in its most general embodiment, a grate plate for a combustion grate with the features of claim 1.

According to one embodiment, the grate plate is formed below the top with a plurality of recesses extending from an area adjacent to the first longitudinal side to an area adjacent to the second longitudinal side and open to the bottom.

These recesses allow a further air cooling of the top from below and thus also of the flowing fluid and / or gas in the channel.

The flow channel or the flow channels extend according to an embodiment perpendicular to the longitudinal side of the grate plate. In other words, the air flow along the flow channels extends in the direction of the front end surface of the grate plate.

The length of the flow channel can normally be limited to a length corresponding to 10-50% of the width of the grate plate, with a length between 10 and 30% or 10 and 20% usually sufficient. This is especially the section that is not swept over by a booster combustion grate. Accordingly, about 10 to 80% of the width of the grate plate is available for the formation of the channel, with 40 to 70% frequently being favorable. Basically, the areas in which the channel or the flow channel runs, could also overlap.

To optimize the cooling effect of the channel can extend substantially over the entire length of the grate plate and extend between the broad sides helical or meander-shaped to increase the length of the cooling channel. By appropriate connection points, the supply and removal of the cooling medium takes place, for example, as described in EP 954 722 B1, reference is made to the.

Usually, a grate plate on the circumference no exact cuboid shape. In particular, the front end face (second longitudinal side) therefore does not run perpendicular to the top of the grate plate. Rather, the second longitudinal side can extend at an angle α <90 ° to the upper side and optionally additionally have at least one further bend.

With regard to the flow channel, this means that the flow channel is not rectilinear, but follows the shape of the grate plate in this area, that is, for example - describes - on average - a semicircle or has several bends. In this way, at the same time results in an extension of the flow channel. An intensification of the cooling is achieved when the flow channel is relatively close to the respective surface areas of the grate plate. In other words, an upper (outer) boundary wall of the flow channel is formed by an (inner) surface of the upper side and an (inner) surface of the second longitudinal side.

A lower (inner) boundary wall for the flow channel can be formed by a rib which extends between walls or webs which form, for example, lateral boundaries of said recesses.

Is the underside of the grate plate (also called rust level) designed so that the top of the grate plate when resting the grate plate on a horizontal surface from the first longitudinal side to the second longitudinal side (ie from back to front) rising (slope, for example: 3-10 ° ), this facilitates the support of adjacent grate plates and the transport of the fuel along the combustion grate.

For this purpose, the underside, the second longitudinal side (front end side) adjacent to be formed with a downwardly projecting shoulder, as shown in the following description of the figures. In this case, the corresponding grate plate with this paragraph is on the following in the direction of transport of the fuel grate plate (rust level).

In contrast, its front longitudinal side terminates preferably at a distance from the upper side of the following grate plate, and correspondingly, the outlet opening of the flow channel is also above the contact surface of the following grate plate. In this way, the targeted flow of the surface of the adjacent grate plate is additionally favored. This too is illustrated and explained in the following description of the figures.

Alternatively, it would be possible to arrange the outlet opening of the flow channel in the lower portion of the front longitudinal side, which would result in an air flow substantially parallel to the top of the following grate plate.

The additional cooling creates the possibility of making the sections of the grate plate which are adjacent to the flow channel thinner than the remaining sections of the grate plate. This not only saves material, but also increases the cooling effect.

This "thinner" section can refer not only to the front longitudinal side of the grate plate, but also to the adjacent portion of the top of the grate plate. The other (first) part of the top of the grate plate, however, is "thicker", because in this section runs the channel.

Grate plates of the type mentioned, for example, have a width of 40-60 cm and a length of several meters. In that regard, it is known to form a grate plate of several, adjoining, interconnected sections, so-called grate bars. The individual sections may be castings, wherein the flow channel and the channel can be formed in-situ. Each section is thus one piece. The sections (grate bars) can also be composed of sub-sections, especially if they are made of sheets be welded. A grate bar, for example, a width (in the longitudinal direction of the entire grate plate) of 30-100 cm, but also beyond.

The connection of adjacent grate bars by means of known connection technology, for example by screwing or in that a plurality of grate bars are connected to each other via connecting rods. Groups of grate bars formed in this way can in turn be connected to each other analogously. In EP 954 722 B1 constructive solutions are shown, which can also be seen how connections of channel sections of the grate bars flow-related.

It is possible, the grate plates in such a way that at least one recess of two adjoining grate bars (sections) is formed, so a grate bar forms a part, for example, one half of the corresponding recess. A flow channel can also be formed by two grate bars.

The invention further relates to a combustion grate, in particular a Schubverbrennungsrost, with a plurality of grate plates of the aforementioned type.

The term "shear combustion grate" includes all types of shear combustion grates, regardless of whether they are horizontal or inclined or the kiln is conveyed in one direction or the other. The term "shear combustion grate" is also not limiting insofar as shearbreasts are detected in which, for example, every other grate plate is movably arranged, but also such grates in which more than a stationary grate plate are placed between grate plates that perform Schürhübe.

Finally, the invention comprises a waste incineration plant, for example a waste incineration plant, with a combustion grate of the aforementioned type.

Other features of the invention will become apparent from the features of the claims and the other application documents. The disclosed features may be essential in any combination for the invention.

Figur 1:

Einen Vertikalschnitt durch eine Rostplatte eines Schubverbrennungsrostes,

Figur 2:

einen Teil-Schnitt entlang der Linie A-A gemäß Figur 1,

Figur 3:

eine perspektivische Ansicht von zwei Abschnitten zweier aufeinander liegender Rostplatten eines Schubverbrennungsrostes.

The invention will be explained in more detail below with reference to an embodiment. Show - each in a highly schematic representation -

FIG. 1:

A vertical section through a grate plate of a shearburning grate,

FIG. 2:

a partial section along the line AA of Figure 1,

FIG. 3:

a perspective view of two sections of two superimposed grate plates of a shearburning grate.

The basic construction of a grate plate is explained with reference to FIG. 1: The grate plate has an upper side 10, a lower side 12, a rear longitudinal side 14, a front longitudinal side 16 and correspondingly two broad sides, which can not be seen due to the sectional view. The upper end face 10o of the upper side 10 is flat. The front, second longitudinal side 16 is angled at an angle α (approximately 45 °) with respect to the surface 10o and then has an angling 16w.

Adjacent to the first (rear) longitudinal side 14, the grate plate on the underside a longitudinally extending (in the plane) recess 18, in which a connector 19 is placed, which has a further recess 19o, in which a round rod 20 is located, on which the grate plate (indirectly) is supported. With the help of this round rod 20, the grate plate shown in Figure 1 in the direction of arrow P is movable. The connector 19 will be described later in detail.

In the region of the bottom 12, each grate plate is formed with a plurality of juxtaposed recesses 22. Each recess 22 is bounded laterally (parallel to the broad sides) of walls, in which case only one wall 24 can be seen. At the rear end of the grate plate, the recess 22 is bounded by a corresponding portion 14a of the first longitudinal side and at the front (in a combustion chamber 26 facing) portion of the front (second longitudinal side) 16th

Between adjacent walls 24 extends a wall 30 which has a substantially arcuate shape in the sectional view and at the front end, adjacent to the second longitudinal side 16, merges into a thickened portion 30v which projects beyond a lower end edge 16u of the front, second longitudinal side 16 and forms a support surface 30u for the grate plate.

This wall 30 forms a lower (inner) boundary wall of a flow channel 32 which extends from the lower end 16u of the second longitudinal side 16 parallel to the wall 30 (thus forming the inner surface of the longitudinal side 16 the other boundary for the flow channel 32) and in its further course is delimited by a lower surface 10u of the upper surface 10 before opening towards the underside 12 of the grate plate. In the illustrated embodiment, the wall 30 ends at the bottom End of the room 22; but he could also end earlier. In the illustrated embodiment, a funnel-like inflow opening 32 k for cooling air is provided, which is provided below the grate plate and the entire recess 22 flows against, including the area below the wall 30th

In the grate plate shown in Figure 1, the part of the cooling air, which is guided through the flow channel 32, symbolized by the arrow K. The cooling air thus enters the flow channel 32 at the funnel-shaped end 32k and is then guided initially along the inner surface 10a of the upper side 10 and then along the inner surface 16i of the longitudinal side 16 before the cooling air emerges in the region of the opening 32o and on the upper side 10 'hits the adjacent grate plate (shown in phantom) and this flows.

The supply of additional cooling air is symbolized by arrows L in the lower part of FIG.

By the flow of the top 10 'of the adjacent grate plate with air of the flow channel 32 adjacent portion is thus additionally cooled from the outside. In this way, caking (so-called welds) by precipitation, in particular metallic precipitates from the kiln, can be avoided, which are indicated in FIG. 1 by the dotted region 34.

Due to the more intensive cooling (additional cooling) in the front, particularly critical part of the grate plate, the wall thickness of the grate plate there thinner than in the rear part can be formed, as the figure shows.

By way of example, the thickness of the upper side 10 in the front part 10v (adjacent to the flow channel 32) is 6 or 8 mm. This applies analogously to the wall thickness of the second longitudinal side 16.

In the illustrated embodiment (Figure 3), the grate plate is formed by a plurality of juxtaposed sections T1, T2 ..., which directly adjoin one another and are connected to one another. These cuts are also called grate bars.

The rear portion 10r of the top 10 is much thicker, for example 25-70 mm thick, to form the channel 40 therein. The channel 40 extends substantially from one broad side of the grate plate to the opposite broad side, and alternately between the first longitudinal side 14 and the front portion 10v of the top. In other words, the channel runs in the region 10r of the upper side 10, which runs behind the part 10v in which the flow channel 32 is formed. In the illustrated embodiment, ports 40a for introducing and discharging a cooling medium are placed on an inner surface of the recess 18. Fluidically close channel sections 40b in the above-mentioned connectors 19, which therefore connect the channels 40 (sections of the channel) of the grate bars and - in the area of the broad sides of the grate plate - simultaneously record connecting lines for the cooling medium (arrow A). The connecting pieces 19 are fastened to the grate bars T1, T2 by screw connections 19v (FIG. 3).

• Kühlung mit Wasser entlang der Kanäle 40 und Kühlung mit Luft entlang der Strömungskanäle 32,
• Kühlung mit Luft sowohl entlang der Kanäle 40 als auch entlang der Strömungskanäle 32.

As already mentioned, the cooling of such a grate plate can take place in different ways, for example:

• Cooling with water along the channels 40 and cooling with air along the flow channels 32,
• Cooling with air both along the channels 40 and along the flow channels 32nd

You can also switch between these states during operation. For this purpose, of course, the water must first be removed from the channel 40, for example, be sucked off.

The holes 36 shown in Figure 1 serve to receive rods for connecting adjacent sections T1, T2. A plurality of such sections T1, T2, for example 5 or 6 sections, form a grate plate.

The grate plate shown is made as a cast iron, each grate bar T1, T2 is in one piece, that is, for example, the wall 30 extends materially to the wall 24th

2 shows that such a grate bar (for example T1) -in the direction of the longitudinal sides 14, 16 of the grate plate -comprises several flow channels 32 (here: seven) next to one another and correspondingly several (here: nine) walls 24. Two adjacent walls 24 each engage around the top 10 and the wall 30 a recess 22. On the outside, the grate bar ends in each case in the middle of the flow channel 32, so that together with a subsequent grate bar (Fig. 3) results in a closed further flow channel 32.

Claims (15)

1. A grate panel for a reciprocating incineration grate, transporting waste, comprising several grate panels arranged in a stair-like fashion, with the following characteristics:

   a) the grate panel has an upper side (10), a lower side (12), two long sides (14, 16) and two broadsides;

   b) the grate panel contains at least one device for connecting a support element (20) adjacent to a first long side (14),

   c) at least one flow channel (32) is arranged underneath and adjacent to a second long side (16) of an adjacent second section of the upper side (10),

   d) at least one channel (40) for conveying a cooling medium extends in a first section (10r) of the upper side (10) adjacent to the first long side (14), characterized in that

   e) the flow channel (32) is arranged such that air can be conveyed along the flow channel (32) from a region that is situated underneath the grate panel to an opening (32o) in the section (16u) of the second long side (16) that is situated adjacent to the lower side (14) so that the air stream is directed thereafter onto the surface of the grate panel, following in the transport direction and cools this surface as well.
2. The grate panel according to Claim 1, realized with a plurality of recesses (22) underneath the upper side (10), wherein said recesses are respectively open toward the lower side (12) and extend from a region (14a) adjacent to the first long side (14) to a region adjacent to the second long side (16).
3. The grate panel according to Claim 1, wherein the flow channel (32) extends perpendicular to the long sides (14, 16) of the grate panel.
4. The grate panel according to Claim 1, wherein the flow channel (32) has a length that corresponds to 10-50% of the length of the broadsides.
5. The grate panel according to Claim 1, wherein an upper (outer) wall of the flow channel (32) is formed by the upper side (10) and the second long side (16).
6. The grate panel according to Claim 1, wherein a lower (inner) wall (30) of the flow channel (32) is formed by a rib extending between walls (24) that form lateral limitations of the corresponding recess (22).
7. The grate panel according to Claim 1, wherein the lower side (12) is realized with a downwardly protruding projection (30v) adjacent to the second long side (16).
8. The grate panel according to Claim 1, wherein the upper side (10) is realized thinner in its section (10v) situated adjacent to the flow channel (32) than in the first section (10r) that accommodates the channel (40).
9. The grate panel according to Claim 1, wherein the second long side (16) is realized thinner in its section adjacent to the flow channel (32) than the upper side (10) in the section (10r) that accommodates the channel.
10. The grate panel according to Claim 1, comprising several interconnected segments (T1, T2) that adjoin one another in the direction of the long sides (14, 16).
11. The grate panel according to Claim 1, wherein the channel (40) of the grate panel is realized in a meander-shaped fashion and essentially extends over the entire length of the grate panel.
12. The grate panel according to Claim 1, wherein the channel (40) can be connected to a supply line and to a discharge line for a cooling medium.
13. The grate panel according to Claim 1, wherein the sections of the channel (40) that lie perpendicular to the long sides (14, 16) extend over 10-80% of the length of the broadsides.
14. An incineration grate, particularly a reciprocating incineration grate, with a plurality of grate panels according to one of Claims 1-13.
15. A waste incineration plant with an incineration grate according to Claim 14.

Images