DE8902692U1 - Grate arrangement for burning garbage and waste - Google Patents

Description

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Description

The invention relates to a grate arrangement, in particular a stepped or step-swivel grate, in particular for the incineration of garbage and waste, with a feeding device and optionally drying and ignition grates.

The residues from garbage and waste incineration are disposed of _in a variety of ways, generally via grates, ash hoppers or the like. However, this is not satisfactory, as the dust, particularly the filter dust from flue gas cleaning, must be subjected to special post-treatment before final storage. Above all, before flue gas cleaning, possible dioxin formation can occur in the dust in the range of approx. 300 ⁰ C and below, which then causes the filter dust to be contaminated with dioxins.

The invention is based on the object of achieving a more effective disposal of slag and filter dust that is more favorable for final storage.

This is achieved in a "grate arrangement of the type mentioned above, surprisingly, by the fact that the last stage of the grate arrangement is designed as a slag melting stage and is characterized by the fact that the slag in the area of the burnout stage is heated to a high temperature, melted and transferred to a water bath. The still unburned components of the burnout stage contribute to the heating.

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The cleaning effect is further increased and disposal improved if the residues are heated by blowing in air, possibly enriched with oxygen, and if the filter dust and its combustion residues are blown into the liquid slag and thus incorporated into it.

The result is a so-called mineralization of these 10

Residues that may then be used in road construction and for

; can be used for other purposes. These compact residues are practically impossible to elute. Above all, possible dioxin formation in the filter dust is prevented by these

Mineralization and integration i-i the slag with 15

liquid slag removal. This enables the now mineralized dust to be disposed of in a safe and environmentally friendly manner.

Even in existing boilers, for example,

Traveling grates with coal firing by such a 20

Waste combustion can be replaced. The same applies to existing waste boilers and their grate combustion systems.

The feed hopper flaps and step swivel grates

are generally known and are for example in the 25

Patent application P 38 04 815.9 described and illustrated.

Above the vortex nozzle grid, an air-pressured pitot tube can be installed with the slag or

Nozzles directed towards the grid should be provided. This results in 30

So there are two areas, namely the burnout grate with increased combustion through the vortex nozzles, on the last ^D lan grate stage also called "vortex component" and the accumulation of the combustion residues.

It is also possible to practically provide the plan grid as a way of creating several

Rows of nozzles are guided. After the burnout and the presence of ash , there is an area in which the heat is increased again. This can be done , for example, by blow-out nozzles in a pitot tube above the flat grate. The tube can be mounted so that it can be rotated and, for example, the tube can be turned away from the tank if liquid slag is not desired.

Conditions arise here, especially if the

Air is added to oxygen, as in a furnace or a forge. The slag reaches temperatures of around 1400 ⁰ C and flows into a tub with an open mouth at the bottom. The tub can consist of two halves, with one half adjacent to the flat grate being slightly bent upwards and forming a collecting basin for the slag. The other half is designed as a drain. There is a sufficient gap between the two halves for the slag to flow vertically downwards. The

Slag can be fed directly into the water bed through box guides 20

Vapor extraction systems in the area of the vertical slag shaft can be provided to extract the vapors and prevent them from adhering to the still liquid slag and causing it to solidify.

funnel-shaped formation below the combustion grate can 25

far into the water bath below. In general, a wet scraper is provided in the water bath below to remove the cooled slag. If no combustion is planned in the area of the grate bars, the blowing

of additional oxygen the slag becomes liquid and flows 30

into a kind of tub 14, from which it can be discharged through a channel (not shown) into the water bath via an outlet opening 20. The channel can be arranged in the middle essentially perpendicular to the tub 14

be foreseen.
35

Slag tappets 15 can be provided in the side walls, which break up the slag once it has solidified. The slag tappet is directed upwards at an angle. The area of the slag pan and the slag channel is rammed with a highly refractory mass, in particular a ceramic coating, in order to avoid any loss of temperature. The ceramic coating is usually held in place by lubricating the channels and the parts that come into contact with the melting slag.

The discharged product has a small surface area and is therefore only open to minimal interactions with the environment.

Toxic substances such as copper or cadmium vapors are neutralized by incorporating them into the melt slag.

Above the liquid slag bath, a transverse

A ventilated, pinned collecting grate should be provided, which has 20

possibly with staggered rows of pipes. Its task is to catch ash droplets still floating in the flue gas and feed them into the melt bath.

An exemplary embodiment of the invention will now be described 25

be explained in more detail with reference to the attached drawings in which

Fig. 1 a first embodiment in section,

Fig. 2 another embodiment, which is rotated by 90° compared to 30

Fig. 1 is shown rotated.

The slag 11 from garbage and waste incineration plants is collected at the end of the grate on a flat grate 4, for example with

Vortex nozzles 2 by means of a sliding distributor 1 to 35

to the pitot tube 5 (along the feeder paths). Even at the end of operation, the feeder pushes forward so that

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no liquid or solid ash remains and can solidify. The pitot tube 5 is a tube arranged across the end of the last grate stage with two or

several parallel rows of directed 5

Outlet vortex nozzles. The tube itself is provided with a ramming mass to protect it against the radiant heat from the melt bath. The tube can be rotated so that the impact points of the jets can be changed. The pitot tube 5 is supplied with air 12 via a fan _, which can be enriched with oxygen 13 in particular. The air is blown directly onto the slag via suitable nozzles 2 on the pitot tube. This causes the slag 11 to be heated due to the

still contained combustible substances to over 1400 ⁰ C 15

heated. On the other hand, air and oxygen cool the pitot tube.

If, as expected, the melting temperature is not reached

are additionally switchable 20

Low pressure lance burners 8 (seen in both figures) are provided in the walls of the melting stage and are switched on to realize the slag flow. Above

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(both stamped) can be connected to the 25

The slag flows from the chute 14 via a groove (not shown) that is recessed perpendicular to the tank into the shaft, into which the slag rams 15 push diagonally upwards and falls into

a water bath with a scraper belt slag remover 10. The slag 30

is cooled there and is in mineralized form and is discharged via the scraper conveyor. The vapor extraction systems mentioned above are not shown.

The filter dust and other residues from the 35

Flue gas cleaning is carried out via injection nozzles 7 or suitable feeder devices for the waste and refuse slag 11

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added and incorporated into the liquid slag discharge.

In the area of the vortex nozzles and the liquid

The grate bars 4 and the Avis flow elements 5 are responsible for slag removal

14 ceramic pads 3 or similar.

For example, highly refractory Mas &bgr; is also held on the pitot tube via steel pins.

The grate can also be surrounded with a highly fire-resistant material IC *

&bull;heat-insulated".

Claims (12)

-1- ADDRESS 1. Remaining arrangement, in particular step and step swivel grates, in particular for the incineration of garbage and waste, with feeding device and optionally drying and ignition grates, characterized in that the last stage is designed as a slag melting stage (5; 8; 11; 3). 2. Grate arrangement according to claim 1, characterized in that the melt slag discharge into the water bath (10) is designed with a scraper conveyor. 3. Grate arrangement according to one of the preceding claims, characterized in that the last grate stage is a flat vortex component stage (2; 3; 4) with vortex nozzles (2) opening upwards from the grate bars is trained.
20 4. Grate arrangement according to one of the preceding claims, characterized in that in the area in front of the end of the vortex nozzle flat grate (2; 3; 4) above it a air-charged pitot tube (5) with on the slag 2b (11) or the flat grate (4) directable nozzles (2). 5. Grate arrangement according to one of the preceding claims, characterized in that, if necessary, 30 To increase the temperature (low pressure lances) burners (8) are provided in the area of the melt slag collecting tank. ^..y.H -2- 6. Grate arrangement according to claim 5, characterized in that a filter dust inlet (7; 7) is provided in the region of the melt slag collecting tank. 7. Grate arrangement according to claim 6, characterized in dap Ä5i£blowing devices (7) are provided for the filter dust. 8. Grate arrangement according to «sine of the preceding claims, 10 characterized by a distributor (1) assigned to the flat grate (4) and transporting the slag to the pitot tube (5). 9. Grate arrangement according to one of the preceding claims, characterized in that in the area of the vortex nozzles (2) and the liquid slag discharge, highly refractory masses (3; 3), in particular ceramic, are stamped on. 10. Grate arrangement according to one of the preceding claims, 20 characterized in that a transversely arranged collecting grate, optionally consisting of offset elements, for entrained slag droplets is arranged in the flue gas path above the slag bath. 11. Grate arrangement according to one of the preceding claims, characterized in that the outlet of the tub is open at the bottom. 12. Grate arrangement according to one of the preceding claims, 30 characterized in that the pitot tube (5) is mounted so as to be rotatable.