EP2751488B1 - Grate for the incineration of solid material - Google Patents

Description

The invention relates to a grate consisting of a plurality of fluid-cooled grate elements for burning solid matter according to the preamble of claim 1.

Large incinerators, such as those used for thermal energy generation or waste incineration, have for receiving and combustion of the solids to be recycled water-cooled combustion grates on which the combustion material is moved through the combustion chamber. A combustion grate has at least one grate row with a plurality of fluid-cooled grate elements, which are arranged side by side and mechanically connected to each other. Cooling fluid is passed through a conduit or channel of the grate element. The channels of the grate elements are usually coupled together in series. Grate elements are also referred to as grate bars or grate plates. A grate may comprise a plurality of grate rows, which are usually brick-like, at least in places are arranged one above the other. The thermal expansion of a grate row is absorbed by arranged at the ends of the rows of rust expansion boxes. In the bars are openings for the supply of combustion air. The juxtaposed grate elements are combined into rows and every other such grate element row is in terms of the advance of the combustion material - ie the periodic execution of Schürhüben - movably mounted and connected to an oscillating drive.

Since these grate elements for the most part in large combustion plants with constantly changing composition of the combustion material, e.g. used in waste incineration plants, the demands on their performance are very high. Considering, for example, that these incinerators are constantly charged with solids that differ by their specific gravity, their calorific value, their air permeability, the moisture content, etc., it is easy to see that such grates are often exposed to very high temperatures and an unusual require technical effort if they are to achieve the desired service life with optimal combustion process. As a result of the heat released during the combustion process, the grate elements are constantly exposed to both chemical corrosion and mechanical wear and must be constantly cooled with a fluid in order to achieve an acceptable service life. Wherein the cooling within the grate rows from the fluid inlet from grate element to grate element to fluid outlet arrives.

With regard to the effective cooling of the highly stressed grate elements, numerous solutions have already been proposed, of which some will be discussed below that are of particular interest in the present context.

The documents EP 1760400 such as EP 0663565 show a grate element made of cast steel, which is part of a water-cooled grate within a plant for the thermal treatment of waste. The grate element through which the cooling water flows has two or more cast steel cooling channels running virtually parallel. The inputs and Outlet openings are preferably arranged directly at the foot-side end of the cooling channel, emerging from the bottom of the grate element. The cooling channels of the grate elements are connected to each other by means of screwed to the grate elements fittings and pipe sections, for example. So-called manifold. Each grate row has a main supply line and a main drain line for supplying and discharging the cooling fluid.

The document EP 1219898 A1 shows a grate block, which is part of a grate within a plant for thermal treatment of waste. The flowed through by the cooling water pipe is in this case arranged between the created as a cast grate block and a separate holding part.

The inlet and outlet of the cooling fluid via pipe systems which are arranged in the region of the grate element carrier to the rear. The supply takes place from a common distribution system and the connection takes place via pipelines with screw connections or weldings.

The document US 1170317 A1 discloses a generic grate in the juxtaposed grate elements are interconnected by flowed through by cooling fluid pipe pieces. The pipe sections are bolted to the grate elements. The document EP 1315936 A1 describes a liquid-cooled grate element with cast-in cooling coils. The liquid coolant is supplied to and removed from each grate element from below in the area of a construction intended to carry the grate elements, also called a grate element carrier. The connection to the cooling system takes place via bolted pipes. The connection to the adjacent grate elements via screwed tubular spacers, called manifolds.

It is also known to provide the grate elements with hose connections to these together connect. The disadvantage is that the hose connections can be damaged by the prevailing high temperatures and by material such as hot metal parts, which fall down the combustion grate.

One of the disadvantages of the prior art is also that, given the use of different materials for the connection to a steel cast grate element with stainless steel fittings high demands on the welded connection and their verification are made. So there is a risk of stress overloading and cracking in the area of the connected steel parts.

Another disadvantage of the prior art is that the welding of the connection connection in the grate element or connecting pipe by hand and is difficult to access.

Another disadvantage of the prior art is that the connection to the adjacent grate element via pipe spacers with screw connections. Due to the constant pulling movement of the combustion grate, the connections to the adjacent grate element are subjected to increased leakage.

A disadvantage of the prior art is that when used separately and then connected to the cast block pipes only very small pipe cross-sections can be realized in the connection points, resulting in high pressure losses and low amounts of cooling water. Pressure losses are also due to the
required fittings and pipe manifold unfavorably increased.

It is therefore the object of the present invention to propose a compound of grate elements for solid combustion, which does not have the disadvantages of the prior art. In particular, a connection of fluid channels is to be proposed, which is characterized by an uncomplicated, economical production.

This object is achieved according to the invention by the characterizing features of a combustion grate according to claim 1.

One of the advantages of the invention is that a small pressure drop of the cooling fluid is ensured by means of the direct coupling of the fluid channels of adjacent grate elements of a grate row of a grate. In addition, large quantities of cooling water can be conveyed through the grate elements, since the grate elements are centered relative to one another and fixed by appropriate fastening means, whereby the leaks usually caused by the pulling movement of the combustion grate are prevented.

The coupling of the fluid channels of grate elements is also referred to below as a fluid connection.

Another advantage of the invention is that the compared to the known fluid connections extremely large cooling water flow area allows higher flow rates with less pressure loss. This leads to a better cooling of the grate elements.

Another advantage of the invention is that with appropriate design of the cooling connections, the fluid connection for water-cooled grate elements made of cast iron with cast cooling channels and grate elements with inserted or cast-in cooling elements can be used.

Another advantage of the invention is that the chosen embodiment of the fluid connection eliminates all welds in hard to reach places with difficult weld preparation and the risk of stress and crack formation.

An advantage of the invention is also that the execution of the grate elements for receiving the fluid connection takes place in connection with the production of the cast grate elements or with mechanical finishing.

Another advantage of the invention is that the material quality of the seals installed in the power bypass also meet the emergency running properties in case of failure of the grate cooling.

An advantage of the invention is that the fluid connection is made of stainless material and therefore insensitive to chemical corrosion and mechanical wear.

A coupling element for adjacent grate elements ensures a detachable, pressure-tight and self-centering fluid connection between adjacent grate elements with a large flow of cooling water and low pressure loss.

• Fig. 1 zeigt eine perspektivische Darstellung einer Ausführungsform eines Rostelements mit seitlich angeordnetem Kanalmündungsbereich eines Fluidkanals;
• Fig. 2 zeigt eine geschnittene Detailansicht einer Verbindung zweier seitlich aneinander angeordneter Rostelemente mit einem Kopplungselement in montiertem Zustand.
• Fig. 3 zeigt eine aufgebrochene Darstellung einer Rostreihe mit Kopplungselementen in einer geschnittenen Ansicht von unten, bei der die Verbindung der gekoppelten Fluidkanäle zweier Rostelemente der Rostreihe sowie die Kühlkanalführung sichtbar ist;
• Fig. 4 zeigt zwei nebeneinander angeordnete Rostelemente in einer Ansicht von unten und fluidmässig miteinander verkoppelt und verschraubt.
• Fig. 5 zeigt zwei nebeneinander angeordnete Rostelemente in einer Ansicht von oben und fluidmässig miteinander verkoppelt und verschraubt.

The invention will be explained in more detail below with reference to the embodiment shown in FIGS.

• Fig. 1 shows a perspective view of an embodiment of a grate element with laterally disposed channel mouth region of a fluid channel;
• Fig. 2 shows a sectional detail view of a compound of two side by side arranged grate elements with a coupling element in the assembled state.
• Fig. 3 shows a broken-away view of a grate row with coupling elements in a sectional view from below, in which the connection of the coupled fluid channels of two grate elements of the grate row and the cooling channel guide is visible;
• Fig. 4 shows two juxtaposed grate elements in a view from below and fluidly coupled and screwed together.
• Fig. 5 shows two juxtaposed grate elements in a view from above and fluidly coupled and screwed together.

This in Fig. 1 Rost element 2 which is shown perspectively has on both longitudinal sides of the side surfaces serving for receiving the solids to be burned shear surface vertically downwardly projecting side walls in which the mouth areas 3 of the running inside the grate elements cooling channels and connection openings 4 for receiving connecting means, such as screw connections are. Next to the grate element a coupling element 1 is shown, which fits into the mouth region 3 of the illustrated grate element 2 and a corresponding mouth region of a laterally adjoining grate element.

Depending on the embodiment of the grate element cooling with cast cooling channels or inserted or cast cooling coils, the position of the recording of the fluid connection is directed to the full length of the grate element side. The same applies to the position of the screw connections. Already in the production of the steel cast grate elements, the openings are taken into account. Depending on the casting process, a mechanical post-processing of the grate elements is required.

In the sectional view of Fig. 2 is a form of the coupling element and its position in the mouth areas of the cooling channels of adjacent grate elements 2 shown. The coupling element 1 described in detail below is sealed by means of a seal 8 against the grate elements 2. The coupling element 1 has a centering part 12, as well as in two axial directions subsequent guide parts 11.

This in FIG. 2 Coupling element 1 shown can be used for the inlet and outlet as a connecting element of fluid and is used independently in the direction of flow.

In the FIG. 2 illustrated embodiment shows a cooling water flow area 5 and a wall thickness 6, which are not limited in dimension and embodiment. The illustrated embodiment is not on the Design and shape of the guide, centering and sealing parts limited.

The coupling element 1 couples the respective fluid or cooling channel laterally adjacent grate elements. The length of the coupling element 1 is formed so that its free ends at least partially penetrate the side wall of a grate element 2.

The coupling element 1 preferably has a circular inner cross section. However, the shape of the coupling element 1 can also be executed in polygonal form. The choice of the thickness of the wall 6 of the coupling element 1 depends on the particular application and the prevailing operating conditions.

The guide parts 11 have a smaller diameter relative to the centering part 12 and serve for guidance and positioning during assembly of the grate elements 2 and terminate in the region of the cooling channels or pipe systems running inside the grate elements. The guide parts 11 are conically shaped with a conicity which corresponds to a formed in the respective mouth region 3 of the grate elements inner cone.

The centering part 12 of the coupling element 1 is used to stabilize and center the grate elements 2 to each other. The centering part is also conical in both directions, wherein the conicity of those of the guide members, so that insertion of the coupling element 1 in the mouth areas 3 can be done without trouble.

The cones or conical sections of guide part 11 and centering part 12 are preferably made with the same tolerances.

Between guide part 11 and centering part 12 a paragraph in the form of a step is available. The paragraph between the guide member 11 and centering part 12 at an angle of 90 ° to the central axis or to an angle of the coupling element 1 to be defined serves as a base for receiving a temperature-resistant annular or polygonal seal. 8

The space or space for receiving the seal 8 is preferably integrally formed on the grate element 2 in the mouth region as a seat or recess, so that a ring-shaped or polygonal sealing chamber is present.

The coupling element 1 is pressed in the assembled state against the deformable seal 8, which is compressed during assembly of the grate elements 2 and adapts to the sealing chamber. The seal 8 seals the grate element 2 with respect to the coupling element 1. By precisely fitting the conical outer shape of the guide member 11 and their low tolerance to the grate element 2 no shear forces acting on the seal.

The volume of the seal 8 is selected larger by a certain factor than the available volume of space, so that the seal 8 is optimally compressed.

FIG. 3 11 illustrates a broken-away view of a grate row 10 of the grate 100 in a sectional bottom view, in which the connection of the coupled fluid channels two grate elements 2 of the grate row 10 and the cooling channel guide is visible. In operation, that is in the normal installation position is the in FIG. 3 shown cooled grate element 2 thus turned by 180 ° to imagine. In this normal operating situation shows the FIG. 5 cooled grate elements joined together, view from above.

FIG. 4 illustrates the cooled grate elements 2 from below in the assembled state, wherein for the rigid connection of two grate elements 2 through holes or holes 4 for receiving screws or for the realization of screw are present. By means of the screw connections, the grate elements are screwed together on block and secured for solubility. The coupling of the fluid channels by means of the coupling element 1 between two adjacent grate elements 2 is ensured via the same screw connections. By tightening the screw the coupling element 1 is pressed into the corresponding channel mouth areas and positioned sealing.

Between two juxtaposed grate elements 2, a so-called diarrhea gap is formed, which is preferably kept small by the mechanical reworking so that solid or burning particles and ash do not fall through the gap.

Reference numeral Legend

100

rust

30

cooling channel

10

Panel series

1

coupling element

11

guide part

12

centering

2

grate element

3

Channel mouth area

4

attachment portion

5

Cooling water flow area

6

Wall thickness

8th

poetry

Claims (11)

1. A grate for the incineration of solid materials, comprising at least one series of grates (10) with a plurality of grate elements (2) arranged beside each other, wherein each grate element comprises at least one fluid channel (30), through which a cooling fluid can flow and which is provided with corresponding channel opening areas (3), wherein the channel opening areas (3) of grate elements (2) which are arranged next to each other are predominantly coaxial to each other, wherein coupling elements (1) are provided for mutual coupling of coaxial channel opening areas (3), which are designed as coupling housings, through which fluids can flow, with at least one guide component (11) and at least one centering component (12), characterized in that, the at least one guide component (11) of the coupling element (1) comprises a tapered, preferably conical external surface to ease mounting and sealing, and/or the at least one centering component (12) of the coupling element (1) comprises a tapered, preferably conical external surface.
2. The incineration grate according to claim 1, characterized in that the channel opening areas (3) comprise of a circular or polygonal inner circumference.
3. The incineration grate according to any of the preceding claims, characterized in that the guide component (11) and the centering component (12) substantially comprise an outer circumference of equal size or comprise different outer circumferences, which are offset to each other.
4. The incineration grate according to any of the preceding claims, characterized in that the coupling element (1) comprises a circular or polygonal inner cross section.
5. The incineration grate according to any of the preceding claims, characterized in that between the coupling element (1) and the grate element (1), when assembled, at least one sealing (8) made of a temperature resistant material is provided.
6. The incineration grate according to claim 5, characterized in that the sealing (8) is arranged in a recess (7) of a corresponding grate element (2), which is provided for guiding the sealing.
7. The incineration grate according to any of the preceding claims, characterized in that each grate element (2) comprises longitudinally, transversely, and/or meanderingly formed cooling channels (30) or a cooling channel (30) configured as a cooling pipe.
8. The incineration grate according to claim 7, characterized in that a cooling channel (30) of a grate element (2), which is configured as a cooling pipe, is removably or irremovably connected, by inserting or molding, for example, with the grate element.
9. The incineration grate according to any of the preceding claims, characterized in that the inlet and/or the outlet for cooling fluid of a grate row (10) of the grate (100) is connected with at least one grate element (2) of the row (10).
10. The incineration grate according to any of the preceding claims, characterized in that an elevation in the form of a step is provided between the guide component (11) and the centering component (12),.
11. The incineration grate according to any of the preceding claims, characterized in that the grate elements (2) comprise side walls, in which connection openings (4) for holding screw connections are arranged, wherein the screw connections ensure the coupling of the fluid channels by means of a coupling element (1) between two adjacent grate elements (2).

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