EP0740110B1 - Method and apparatus for the treatment of solid combustion residues from an incinerator - Google Patents

Abstract

The method involves a furnace grate and an adjacent, liq. filled slag remover with fall shaft and push-out plunger, via which the combustion residue are removed via an upwards rising push-out chute. The combustion residue is washed in the slag remover, in which the residue is buffered by corresp. regulation of the outlet velocity in the fall shaft, while the washing liq. flows through the residue from top to bottom. Pref. the solid residue is kept above the liq. level in the fall shaft.

Description

The invention relates to a method and an apparatus for the treatment of solid combustion residues a waste incineration plant.

The combustion residues are known from DE 711 606 C. in one, a chute and a purification container with increasing discharge chute To promote detoxification and from there by means of a To push out the push rod. This is the purification container the water to quench the slag fed, with only so much fresh water in this detoxification tank is introduced as with the slag is carried out by moistening them. It turns out an equilibrium concentration with respect to numerous in the Residues of adhering substances and compounds, e.g. Salts one, so a decrease in their concentration is not is possible. This results in unsatisfactory properties the slag in terms of landfill capability and further processing into building materials.

EP-C-0 304 412 discloses combustion residues at least one basic and advantageous then also undergo an acid wash to not just the water-soluble components, but also the heavy metals loosely bound into the slag remove. Here is a relatively large apparatus Effort necessary, the equipment provided for this downstream of the detoxifier.

DE-C-524 207 discloses slag in one Damming the shaft and sprinkling it with water from above. This shaft has an obliquely arranged, water-permeable Wall through which the fire water is drained can. The aim of this invention is to reduce the slag as much as possible pre-dried to be removed from the shaft and onto a conveyor belt bring to dirt by dripping of the extinguishing water during the subsequent removal avoid. The result is that there is only so much water for sprinkling is fed as it is for quenching the slag is required.

From GB-A-379 508 is a discharge device for Combustion residues are known in which the effluent Multiple wash gases through water bath and shower heads is subjected to, while the solid residues by means of a scraper conveyor from a shaft into a liquid container introduced and deleted there. A Slag washing in a chute in which the Wash liquid trickles down from the top to the to be able to wash all slag in this chute is not provided there.

In a deslagging device known from US-A-4,020,773 are in the chute above the slag container Spray nozzles provided the liquid on the Bring slag, which can be swiveled into a chute Fall flap and be deleted there before entering the Detoxifying tank by swiveling the flap be dropped. Accumulation of slag in the chute and the supply of washing liquid that the entire Slag in this chute for the necessary Washing process recorded is not provided there. An accumulation of slag in the chute would make it pivotable the flap.

The object of the invention is to minimize the outlay on equipment to avoid and still treat the solid Allow combustion residues to be satisfactory Slag properties with regard to landfill ability and further processing lead to building materials.

This object is achieved by the specified in claim 1 Measures solved.

By washing the solid combustion residues already in the Detoxification becomes a large part of the known expenditure on equipment avoided. The decisive improvement over the There is slag washing with water in the conventional sense to see that the solid combustion residues in the detoxifier to be dammed up or piled up, which means for the washing liquid a much longer exposure time is available, so that due to this fact, improvements over the usual slag washing can be detected, even if the Washing liquid consists only of water. The Combustion residues are thus despite little equipment Expense largely freed of pollutants, causing them to Landfills can be deposited or processed into building materials.

A major improvement in the separation of In a further development of the invention, heavy metals are achieved by that a chemical, preferably acid, e.g. Hydrochloric acid or phosphoric acid is used, whereby by the Accumulation or piling of solid combustion residues, especially beyond the liquid surface, especially good ones Requirements for washing with a chemical, especially acid, as created by the piling up of the Combustion residues have to travel long distances for the washing liquid through these combustion residues and thus large Residence times are available without additional containers or reactors a satisfactory washout of Heavy metals from solid combustion residues guarantee. By accumulating the combustion residues The washing liquid comes above the liquid level or chemical initially with dry combustion residues in Touch and that in the chute, in which none special mechanical effects on the walls of the Einfallschachtes occur, so that here for its manufacture Materials can be used that are strong for use Acids are suitable. Until after the appropriate trickle the washing liquid or chemical through the combustion residues this reaches the liquid level below which the push rod is in the case of an acid Washing liquid, this due to the basic combustion residues neutralized so far that an attack on those parts of the Detoxifiers that are inside the liquid and one subject to particularly high mechanical abrasion, which is why this Parts made of acid-resistant material at unreasonable costs can be produced is no longer to be feared. The Piling of solid combustion residues within the Inlet well beyond the liquid level is one essential requirement for the use of chemicals, especially acids within the detoxifier.

If in a further embodiment of the invention in countercurrent to the Washing liquid flowing through the combustion residues from above Fresh water or a chemical, especially bases, such as e.g. Sodium hydroxide solution or phosphates, e.g. the salts of Phosphoric acid, is supplied at the end of the expulsion of the detoxifier, this will not only improve integration residual pollutants remaining in the combustion residues achieved, but also a wash off during the Washing process detached or triggered components that are attached to the solid combustion residues can accumulate again. In addition it also ensures that the lower part of the detoxifier is not is added with fine combustion residues, the one Prevent the coarser combustion residues from being pushed out would. In addition, this can ensure that when Use of an acidic washing liquid those parts of the Detoxifier that is not made for reasons of abrasion resistance Acid-resistant material can be made, not with the acidic Wash liquid come into contact because this is due to the im Countercurrent washing liquid in the form of fresh water or prevented in the form of a chemical.

To remove the organic sludge from the washing process Substances, water soluble parts and Remove heavy metal components safely from the detoxifier can in a further embodiment of the invention Washed out products loaded in the detoxifier Detox water at the bottom of the chute set liquid surface within that of the chute limited area or removed from the detoxifier. This ensures that the detoxifying water or Sludge in an exhaust duct, as this with fine particles loaded detoxifying water no longer under the back wall of the Inlet shaft into the rear area of the detoxifier must flow where this sludge in the usual laundry the slag was removed with water. That kind of peeling the resulting sludge is particularly special advantageous if starting with washing liquid in countercurrent is worked by the expeller, since in the area of Liquid surface at the bottom of the chute the two Currents meet within the detoxifier so that on the one hand, the one already trickling down in the chute Washing liquid separated components and on the other hand those Components that can be removed from the combustion residues can be removed have accumulated again and by the end of the extension imported washing liquid are rinsed off. At this advantageous way of removing sludge from organic Substances, water-soluble parts and heavy metal components, in an advantageous development of the invention such Regulation of the take-off speed takes place that the entrainment of Solid particles with a grain diameter of up to 2mm is made possible, it is ensured that fine parts of the slag that a grain fraction up to 2mm include be deducted. This is advantageous because in these fine parts a particularly high one Concentration of pollutants and especially heavy metals is present.

This removed from the detoxifier and with Wash-out products of the type described above Detoxifying water can be used in a further embodiment of the invention either one downstream of the combustion process Emission control device or a washing stage Neutralization of acidic, coming from the combustion process Exhaust gases are supplied. At the first option, this will be Detoxifying water evaporates in the exhaust gas stream, being acidic on the one hand Exhaust gases can be neutralized and on the other hand around the To expel water content. The dry part the other Filter dusts from the exhaust gas of the incinerator were deposited. The second option is the use of the detoxifying water to neutralize acidic Exhaust gases in wet scrubbers.

Depending on the chemical composition of the combustion residues and the washing liquid used, it can be advantageous be if in a further embodiment of the invention at least one Part of the removed waste water in the circuit in the Inlet chute for washing the combustion residues is returned.

This at the lower end of the chute or from the Detoxified water can be removed advantageously those falling through the grate Combustion residues are added so that they do not get into an additional special detoxifier need what is necessary when together with others, im Detoxified washed out flammable components in the Combustion process should be reintroduced because the Return of combustion residues that have fallen through the grate directly into the feed chute because of a possible Risk of fire is not possible.

Preferably, the applied in the area of the upper end of the fall shaft amount of washing liquid is 0.2 per tonne of combustion residues to 20 m ^3, while the fed in countercurrent at the Ausschubende of the ash amount of the washing liquid is 0.2 to 4 m ³ per ton of combustion residues.

The device for carrying out the method is marked through a detoxifier, in the area of the upper end of the chute a device for feeding Wash liquid are provided through which the wash liquid can be distributed over the entire cross section of the chute. As a result, a uniform irrigation of the Combustion residues reached with washing liquid. This Washing liquid can either be circulated Detoxifying water and / or a chemical, preferably one Acid.

The device for supplying washing liquid can in advantageously comprise spray nozzles in the side walls of the chute are provided. This configuration allows not just an even sprinkling of the combustion residues with washing liquid but also enables trouble-free Failure of solid combustion residues.

The device for supplying washing liquid can also include perforated tubes that cross the chute. The Holes in the tubes act as spray nozzles. Since one with few tubes is a disability within the Falling way of the combustion residues practically not exist.

If in a further embodiment of the invention by the push rod mechanically stressed parts of the detoxifier from an abrasion-resistant but not resistant to acid Material and less mechanically stressed parts, especially the walls of the chute from an acid-resistant Such a detoxifier is special economical for the use of an acidic washing liquid suitable.

For an additional washing liquid in counterflow to the to be able to feed slag to be discharged in a simple manner, are spray nozzles on the discharge side of the detoxifier Fresh water or washing liquid is provided which is even Distribution of the liquid to that on the discharge chute allow existing combustion residues.

If the detoxifier in a further embodiment of the invention one of its liquid level inside the chute or of the detoxifying outlet duct with an airtight one locked sedimentation tank is connected, so a safe and controllable removal of the in the detoxifier due to the Washing process of the detoxifying water including the suspended fine particles without the risk of that false air in the combustion chamber operated with negative pressure can penetrate.

It is recommended to use the sedimentation basin with the collecting funnels for the combustion residues falling through the grate to connect via vacuum locks, as this will result in extinguishing of these combustion residues without additional detoxifiers is possible in a simple manner.

Figur 1:

einen Entschlacker nach dem Stande der Technik;

Figur 2:

eine erste Ausführungsform einer Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens;

Figur 3:

eine weitere Ausführungsform einer Vorrichtung nach der Erfindung; und

Figur 4:

eine bevorzugte Ausführungsform der Vorrichtung nach der Erfindung.

The invention is explained in more detail below on the basis of exemplary embodiments of a device for carrying out the method comprising a detoxifier. The drawing shows:

Figure 1:

a prior art detoxifier;

Figure 2:

a first embodiment of an apparatus for performing the method according to the invention;

Figure 3:

a further embodiment of a device according to the invention; and

Figure 4:

a preferred embodiment of the device according to the invention.

FIG. 1 shows a known detoxifier, which has a total of 1 is designated, the one chute 2, an extension chute 3rd and one in the rear area 4 of the detoxifier driven swivel arm 5 includes articulated push rod 6, that falling from a grate, not shown Slag over the rising chute 3 into one Extends chute 7. By means of an inlet 8 fresh water supplied becomes a constant in the detoxifier 1 Liquid level 9 observed, which is set so high that the lower edge 2a of the chute 2 is immersed in the water. This known detoxifier does indeed Slag washing by water, with waste water via a drain 10 is withdrawn at the rear end 4 of the detoxifier 1, however is a large proportion of the fine ingredients that are not under the Immerse the lower edge of the chute together with the Slag discharged into the discharge chute, which is the reason for the unsatisfactory properties of the slag already explained above represents.

From the representations of the devices according to FIGS. 2 to 4 one of the essential features of the invention becomes apparent, the is that in the slag chute 2 with the 11th designated slag is piled up, the piling preferably far beyond the liquid level 9 in Inlet shaft 2 takes place. On this occasion it should be noted that all components with the detoxifier according to the state of Technique match, the same reference numerals as in Fig. 1st receive.

In the embodiment according to FIG. 2, the light essential components of the detoxifier 1 the same conditions before as in Fig. 1. For this reason, only the Deviations explained. In this shown in Fig. 2 Embodiment is the regulation of the extension of the Push rod 6 set so that the slag 11 in Inlet chute 2 piled up. The washing liquid that Water and / or a chemical, preferably an acid can, is supplied via a ring line 12, the spray nozzles 13 is connected, which in the side walls of the Inlet chute 2 are provided. These spray nozzles 13 allow sprinkling of the piled up slag 11 within the chute 2 over the entire cross section the same. The deduction of the one loaded with washout products Detoxifying water takes place via a discharge line 10, which runs from rear area 4 of the detoxifier 1 goes out.

Fig. 3 shows the same structure of the essential parts of the Detoxifies an amendment to the execution form Fig. 2. In this embodiment, a washing liquid, the Water or a chemical, especially a base or Phosphate compounds can be via the inlet 8 in Discharge shaft 7 of the deslagger 1 is supplied. That about the Discharge line 10 from the rear room 4 of the detoxifier drawn off detoxifying water loaded with washout products is by means of a pump 14 leading to the spray nozzles 13 Ring line 12 pumped via a line 12 a. It is about a Valve 15 and another line 16 part of this already branched loaded liquid to the one hand the Liquid level 9 in the detoxifier 1 on a certain To maintain what is due to the hydration by the Inlet 8 is necessary and on the other hand the concentration entrained sludge, salts and other pollutants not to let it grow too high. In this embodiment the sprinkling in the chute 2 takes place Slag 11 by circulating deslagging water, the via a line 12b opening into the ring line 12 with a Chemical, preferably an acid, can be added. By the constant liquid supply at the inlet 8 and the discharge of Detoxifying water via the valve 15 and the line 16 is the Concentration of absorbed pollutant parts on one held certain level.

In the preferred embodiment shown in FIG Device for performing the method is fresh water or a chemical, preferably a base or a substance from the Group of the phosphates via the inlet 8 into the discharge shaft 7 introduced. For sprinkling those piled up in chute 2 Slag 11 also serves as in the embodiment according to FIG. 3 a chemical, preferably an acid and / or in circulation guided detoxifying water. The latter becomes a sedimentation basin 17 removed, which is sealed airtight and over a Extraction channel 18 is connected to the detoxifier 1, wherein the exhaust duct 18 from an area at the level of Liquid level 9 within the chute 2 or the underlying detoxifier goes out. The one labeled 19 Return line leading to the spray nozzles 13 in the upper area of the The chute 2 leads is fed by a pump 20, which Detox water from the settling tank 17 at a near the there aspirating liquid level 17a, if possible suck in little solid particles. By means of a Return line 19 opening line 19a can the spray nozzles 13 a chemical in addition to the detoxifying water, preferably an acid can be supplied. The chemical can but can also be supplied instead of the detoxifying water if this requires treatment of the combustion residues. about a discharge line 21, in which a shut-off valve 22 is located by means of a further pump 23 liquid from the settling tank 17 deducted at its lower end where the detoxifying water enriched with these by the sinking solid parts is. The amount withdrawn is regulated by the pump 23 in such a way that in the discharge channel 18 with the liquid level 9th is connected within the chute 2, such Pull-off speed is reached that only solid parts up to a grain size of 2 mm are subtracted. The in Diameter parts above are with the rest coarse slag parts through the push rod 6 over the Extension chute 3 pushed out.

Claims (19)

1. Process for treating solid combustion residues of a waste incineration plant in which the combustible materials are burned on a firing grate, then transported into a deslagger (1) filled with liquid, from which they are transported out via an ascending discharge shute (3), the combustion residues accumulating in the inlet shaft (2) of the deslagger (1) by appropriate control of the discharge rate and being washed by wash liquid which flows through the combustion residues from top to bottom.
2. Process according to Claim 1, characterized in that the solid combustion residues are accumulated above the liquid level in the inlet shaft.
3. Process according to Claim 1 or 2, characterized in that a chemical, preferably an acid, is used for the washing.
4. Process according to one of Claims 1 to 3, characterized in that fresh water or a chemical, preferably a base or phosphate compounds, is fed at the discharge end of the deslagger in countercurrent to the wash liquid flowing through the combustion residues from the top.
5. Process according to one of Claims 1 to 4, characterized in that the deslagger water arising in the deslagger and is loaded with extraction products is taken off at the liquid surface set at the lower end of the inlet shaft within the region delimited by the inlet shaft or is taken off from the deslagger.
6. Process according to Claim 5, characterized by a takeoff rate which makes possible entrainment of solid particles having a particle diameter of up to 2 mm.
7. Process according to Claim 5, characterized in that the deslagger water loaded with extraction products, after it is taken off from the deslagger, is fed to an exhaust gas emission control system downstream of the combustion process.
8. Process according to Claim 5, characterized in that the deslagger water loaded with extraction products, after it is taken off from the deslagger, is fed to a scrubbing step to neutralizing acidic exhaust gases originating from the combustion process.
9. Process according to one of Claims 5 to 8, characterized in that at least part of the deslagger water which has been taken off is recirculated to the inlet shaft for washing the combustion residues.
10. Process according to Claim 5, characterized in that the combustion residues falling through the firing grate are added to the deslagger water taken off at the lower end of the inlet shaft or from the region of the deslagger.
11. Process according to one of Claims 1 to 10, characterized in that the amount of wash liquid fed in the region of the upper end of the inlet shaft is from 0.2 to 20 m³ per ton of combustion residues.
12. Process according to one of Claims 1 to 7, characterized in that the amount of wash liquid fed in countercurrent at the discharge end of the deslagger is from 0.2 to 4 m³ per ton of combustion residues.
13. Apparatus for carrying out the process according to one of Claims 1 to 12, characterized by a deslagger (1) in which a device (13) for feeding wash liquid is provided in the region of the upper end of the inlet shaft (2), via which the wash liquid can be distributed over the entire cross section of the inlet shaft (2).
14. Apparatus according to Claim 13, characterized in that the device for feeding wash liquid comprises spray nozzles (13) which are provided in the side walls of the inlet shaft (2).
15. Apparatus according to Claim 13, characterized in that the device for feeding wash liquid comprises perforated tubes which traverse the inlet shaft (2).
16. Apparatus according to one of Claims 13 to 15, in particular for carrying out the process according to Claim 3, characterized in that the parts of the deslagger (1) which are particularly mechanically stressed by the discharge ram (6) consist of a wear-resistant, but non-acid resistant material, and the less mechanically stressed parts, in particular the walls of the inlet shaft (2), consist of an acid-resistant material.
17. Apparatus according to one of Claims 13 to 16, characterized in that spray nozzles for fresh water or wash liquid in the form of a chemical, preferably a base or phosphate compounds, are provided at the discharge end (7) of the deslagger (1), which spray nozzles permit uniform distribution of the liquid onto the combustion residues situated on the discharge shute.
18. Apparatus according to one of Claims 13 to 17, characterized in that the deslagger (1) is connected via a takeoff duct (18) starting from its liquid level (9) within the inlet shaft (2) or the deslagger to a settling tank (17) which is sealed air-tightly.
19. Apparatus according to Claim 18, characterized in that the settling tank (17) is connected to the collecting hoppers for the combustion residues falling through the firing grate via vacuum locks.

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