EP0345285A1

EP0345285A1 - Pivoting step grate arrangement providing air nozzles.

Info

Publication number: EP0345285A1
Application number: EP88901824A
Authority: EP
Inventors: Balduin Pauli
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-02-18
Filing date: 1988-02-16
Publication date: 1989-12-13
Anticipated expiration: 2008-02-16
Also published as: DE3804815A1; EP0345285B1; DE3866699D1; ATE70121T1; US5033396A; WO1988006256A1

Abstract

PCT No. PCT/EP88/00113 Sec. 371 Date Aug. 1, 1989 Sec. 102(e) Date Aug. 1, 1989 PCT Filed Feb. 16, 1988 PCT Pub. No. WO88/06256 PCT Pub. Date Aug. 25, 1988.The invention relates to a grill arrangement, particularly for stepped pivoting grills, with feeding means, possibly drying and firing grills and at least one vertical grill with associated horizontal grill as well as a firing burnout grill and is distinguished by at least one swirling component step (3) in the stepped pivoting grill.

Description

Grate arrangement, especially for step swiveling grates

The invention relates to a grate arrangement, in particular for stepped pivoting grates, with feed device, optionally drying and ignition grate and at least one steep grate with an associated flat grate and a burnout grate connected downstream.

Such step swiveling gratings have proven very successful in practice. It is already known (P 28 33 255.0) to provide such step swiveling gratings, the individual steps of which consist of a flat and a steep grate, with air-cooled grate bars, the air being introduced, for example, centrally in the grate bar, via ducts below the grate bar top to both The sides are distributed and the air is discharged into an air distribution box under the flat and steep grate, from which it enters the combustion chamber via the slots between the grate bars along the flanks of the grate bars.

It is now important to further develop this extremely advantageous construction in such a way that the combustion output is increased or intensified and the combustion process is optimized and the combustion-dependent ones

Pollutants such as NOx, CO, C total, and the accumulation of hydrocarbons CnHm can be minimized.

This is surprisingly achieved according to the invention in a grate arrangement of the type mentioned at the beginning by at least one vortex component stage in the stepped pivoting grate. The vortex component stages are preferably designed such that at least some grate bars have blow-out openings for air. It is beneficial if high-speed jets are vertical

5 Blow out to the flat grate level.

The measure according to the invention thus fully achieves the above-mentioned object, i.e. the combustion output increased considerably and 0 intensified the combustion process optimized and the combustion-dependent pollutants, such as NO, CO,

C total. and hydrocarbons CnHrn, are minimized,

15 Via the so-called vortex components (vortex step within the framework of a step grate), absorbents such as e.g. Lime, can be added, which can result in an inclusion of harmful substances.

Is 0 In addition, ^"a surface enlargement of the Brenn¬ fabrics by abrasion in the fluidization set; the combustion process is favored This is done in particular with the addition of centrifuged Klär¬ mud with drying substances by 30% and the zumMüll geme.

25 seeds burning waste and sewage sludge.

In the area of the swivel grate elements equipped with so-called swirl components, a quasi-fluidized bed is created, which the fuel must pass through on its way.

30

In this case, fuel transport and the transport of the fuel residues and their discharge take place in the usual way, as on any grate system, in particular step grate systems. ύ o , So the good qualities of one are combined

Rust and fluidized bed firing through such a system.

The resulting fluidized bed additionally transports fuel or residue. The residues are finally discharged via a known type of detoxification system.

In a further development of the invention, the vortex nozzles are to be protected even better, the grate arrangement is to be kept even cleaner and the temperature resistance is to be increased as much as possible.

For this purpose, the grate bars of the flat grate arrangement will preferably carry a slag-repellent ceramic coating of high temperature resistance that embeds the vortex nozzles. This can also be done at least in the lower part of the steep gratings.

The ceramic coating expediently consists of slag-repellent silicon carbide, which can be stamped, for example. The ceramic material itself has an additional holder through the swirl nozzles. The arrangement of flat gratings with dividers and grids of this type is particularly suitable for special waste such as hospital or chemical waste, which is partly placed in containers with liquid content or becomes doughy or liquid in the burning phase. The grate construction is absolutely tight down here.

The high speeds at which the air emerges from the vortex nozzles do not allow liquids to penetrate into the nozzles themselves. The slag-repellent ceramic material, which is suitable for very high thermal loads, has a high wear resistance and a long service life compared to the previously used heat-resistant Sicromaist steel. The new combustion concept thus offers a real alternative for systems with smaller special waste throughputs of approx. 100 kg / t to a maximum of 2 t / h compared to the tried and tested rotary kilns. The measure according to the invention, ie targeted air flow and the combustion chamber adapted to the combustion process with the long dwell times for the flue gases in the high temperature range, make the firing-dependent pollutants such as CO, NO, total C, dust and traces of furans and dioxins optimal min

The ceramic aterial support can also be provided in the area of the vortex nozzles in the case of swivel gratings. Here too, an extremely intensive combustion with high thermal stress for the grate material is provided in the areas of the grate bar where the vortex nozzles are arranged. Optionally, the ceramic material can also be built on. The grate bars can also be delivered individually. The invention surprisingly uses the favorable properties of silicon carbide (for example Ulimann Volume 21, page 431 to page 436).

For example, embodiments of the invention will now be explained in more detail with reference to the accompanying drawings. These show in

1 shows an overall representation of an embodiment according to the invention;

FIG. 2 shows a stage of the stepped pivoting grate according to FIG. 1;

3 two assigned grate bars of a stepped grate gradation;

4 shows a detail of FIGS. 2 and 3;

FIG. 6 shows a multi-stage feed grate with vortex components. FIG. 6 shows a feed grate element with special consideration of the interlacing zor. FIGS. 7 and 8 show a nozzle arrangement n with an air shut-off valve n

7 with the nozzle open; FIG. 8 with the nozzle blocked; 9 shows a further embodiment of a flat grate bar with special protection;

Fig. 10 shows a cross section of this and

Fig. 11 is a plan view of Fig. 9; Figures 12 to 14 an arrangement similar to Fig. 9 to

11, but a different attachment of the ceramic support;

Fig. 15 schematically flat grate arrangements with allocators un

Fig. 16 details of a swivel grate stage.

1 shows a stepped swivel grate system with waste disposal 1 with a feed flap, allocation slide (not designated) and a swivel grate system, which consists, for example, of two stepped swivel grate steps 2 (each consisting of a steel grate and a flat grate) and (at the end of the grate) a further swivel grate step 2, there is a burning grate (not designated) and a detox 6. So-called vortex components 3 (two stages, in each of which a fluidized bed is generated, or stages in which at least swirling air is blown out) are switched into the stepped swivel grate system. The firebox 4, arrangement and design of the burner 5 and the arrangement of air distribution boxes 7 are known per se. n In the area of the so-called vortex components, air is blown out from below in a manner that swirls in an arbitrary manner. In this area, a vortex zone, that is to say a quasi-fluidized bed, is generated in a way that was previously completely unusual in the stepped pivoting grate area (probably also unusual in the stepped grate area). This must be traversed by fuel, which in principle is moving downwards. This fuel can be made from garbage, partially dried sewage sludge or

10 also consist of other mostly difficult to burn solid or semi-liquid "fuels".

The garbage, for example, from the garbage infeed 1 to the butterfly valves (not shown) can be

• _j _ if necessary, there or later, after falling onto the distribution slide, and then conveyed to a drying and ignition grate 2. The ignition can therefore already take place in the area of the first or second stepped pivoting grate element. At the latest at handover

20 of the fuel to the step swiveling grate stages 3 working with a kind of fluidized bed, the above is done: the lighter fuel reactions are lifted and in which we continue to burn. An abrasion occurs. The combustion process is due to the increase in surface area

25 favored, especially when centrifuged sewage sludge with dry substances was added by 30%. On the two stages shown with fluidized bed 3, the good properties of grate firing with a fluidized bed are therefore combustion-related.

QQ firing combined. After passing through the two pivoting grate elements 3; 3 for combustion and swirling, the fuel is transferred to two swiveling grate elements 2 for burnout and residue transport.

ao The air supply to the two swivel grate elements 3 for

Combustion and swirling are provided in particular for cooling the grate bars (not shown). As a result (FIG. 2), each grate bar is supplied with cooling air in the center from below, for example from an air distribution box (not shown), which can be provided inside or outside an air funnel 7 (FIG. 1). In general, the air is passed over a cap welded onto the top of the grate bar, for example (likewise not shown). The air supplied in the center emerges on the end face in the area of the pivot bearing for the grate bars on the one hand and in the area of the opposite grate bar end on the other hand. The same applies to the grate bars of the steep section. Air is then blown out of the air distribution box 7 into the combustion chamber by means of a respective blower via nozzles 8 and ensures the swirling described.

In the present exemplary embodiment, each grate bar of the flat grate has three nozzles 8, which are provided approximately in the middle between the swivel grate bearing 9 and the grate bar end 10. The nozzles are otherwise evenly distributed over the entire width of the grate bar. In the exemplary embodiment, three rows of such nozzles are provided and form the swirl zone. Due to the discharge of high-speed air from its own fans, the fuel is swirled and swirled: the lighter fuel fractions are to a certain extent subjected to abrasion and reduction and are in the

Suspended air burned or transported to the burnout grates 2 '. The heavier fuel fractions are transported to the burnout elements 2 'both by means of the lifting movements of the swivel grates and by the dynamics of the air flowing out of the nozzles 8. The residues of the substances burned in suspension are classified according to the swirling zones 3; 3 discharged with the flue gas stream or via the burnout elements 2 ¹ and the purification device 6. Because the nozzles are seated in the pivotable grate element, the pivoting movements bring the nozzles into a changed position, as a result of which the outflow angle of the nozzle air changes with respect to the general flow of the flue gases in the combustion chamber. This is particularly illustrated in FIG. 3. The lifting of the steep grate 12 when the pivoting flat grate element 9; 10 takes place in the usual way.

According to the exemplary embodiment, the nozzles are formed by a silicon tube 13, on which a metal hose 14 is seated as an air supply.

Fig. 4 shows a further detail. Two grate bars lying next to one another each carry three nozzles 8, the nozzle diameter of which can be 2 to 10 mm depending on the air outlet speed. In order to achieve particularly good swirling, the intermediate distances between the nozzles with 150 mm and the distance to the edge of the grate bar with 300 mm will be selected for a conventional stepped swivel grate.

Of course, it is also possible to incline the axes 15 of certain nozzles with respect to the axes of other nozzles, for example in such a way that, according to FIG. 2, the axes of the middle rows of nozzles from nozzles 8 perpendicular to the grate, the inner and outer rows of nozzles at an angle of attack blow against the middle row of nozzles.

If adsorbents, in particular lime, are to be blown out, the nozzle outlet, the inner surface of the nozzle and the nozzle diameter can be adjusted accordingly if this should be considered necessary. Another embodiment is shown in FIGS. 5 to 8.

This involves a step grate with three grates 20, 20 'and 20 "and a burnout grate 20"''. Garbage, for example hospital garbage, is put into the lock task 22, for example via a lifting system and generally in bags. A slide piston 24 pushes periodically in front of the hospital garbage by opening a fire chamber flap 26. After predrying on the grate 20, the garbage falls or is pushed onto the grate 20 '. Primary air 28 is supplied in the area under the grate 20. After partial burning out on the grate 20' it is inserted Allotment 30 removes the garbage from the grate 2. The same takes place on the next stage through the allocator 32. The burnout grate 20 '''is otherwise designed in the usual way. A power and heating burner 34 is at an angle with secondary air 36 ( both provided in the masonry 38) A detail of the grate step 20 'is shown in Fig. 6. The same reference numerals mean the same parts in both figures again formed as fluidization with three rows of nozzles 40 'of nozzles 8' and has proved ^'to be expedient. The invention is not limited to this. Since the hospital waste is partly pasty, liquid or mushy, special nozzle shapes are provided. It is a (FIGS. 7 and 8) nozzle shape, in which the air exits the tube 44 into a reduced piece of tube (nozzle) 46. The nozzle 46 is opened or closed by a plunger 48. The pestle is part of a rake. All nozzles in a row or part of the nozzles in a row can be opened or closed by means of the respective tappet 48 using this rake. The closed state is shown in Fig. 8. The plunger is a fire-resistant plunger, generally made of a solid material. Since the multi-stage feed grate is equipped with fixed and cooled grate bars (not shown separately) for burning hospital waste and other special waste, which comprises pasty and sticky substances, the additional air outlet nozzles 8 'are therefore provided. These outlet nozzles represent vortex components which can also be closed with the aid of devices of a different design so that liquid, pasty or sticky substances cannot get into the nozzles during start-up and shutdown as well as during operation of the system.

Fig. 7/8 explains the possibility of cleaning the nozzles of residues by retracting the tappet (nozzle blocked). Each rake with tappets spaced between the nozzles carries 8 to 15 nozzles.

In the case of, for example, three rows of nozzles, one or two nozzle rakes can also be closed, as a result of which the air time allocation and thus the combustion process are controlled.

The penetrations of the computer system from the supply air system are hermetically sealed. The arrangement and design of the closure system in the area of the supply air system for the nozzles is shown in FIGS. 7/8. The nozzles are cleaned, for example, by advancing the feeder 30 and thus cleaning the nozzle orifices or nozzle heads. After the feeder has been withdrawn, the doughy remaining residue is burned more quickly.

The nozzles can be sealed or closed during start-up. This prevents sticky, doughy or liquid substances from entering during start-up, but also during operation. FIG. 9 shows a grate bar with ceramic material support 51 in which the swirl nozzles 54 are embedded. The ceramic pad consists (in Figures 9 to 16) of slag-repellent material with high temperature resistance. It is applied to a steel carrier 52, which at the same time has the function of an air supply duct with the air supply pipes 53 required for this.

The grate bar rests on supports 55 in a manner known per se.

According to FIGS. 12 to 14, a lateral holder is provided for the additional holding of the ceramic material applied to the steel supports 52. This can also consist of sicromal steel. As can be seen in FIGS. 13 and 14, this holder engages around the stiffened

Material and runs like a rail on both sides of the grate bar, preferably over its entire length. The ceramic material support is thus held in this embodiment once by the air-supplying steel support 52, once by the nozzles 54 and then by the side brackets 56. The grate bar itself lies on the support beams 55 and is airtight at the bottom.

Fig. 15 shows an arrangement of two flat gratings with known distributors 57 and the grate bars 58. This flat grate arrangement in the form of a staircase with distributors is particularly suitable for special waste such as e.g. Clinical and chemical waste, some of which are placed in containers with liquid contents or become doughy or liquid in the burning phase. Since the grate construction is absolutely tight at the bottom and therefore no liquids can drip through the grate, the design for hazardous waste is convincing. The masonry and the burnout grate 60 are only indicated.

Claims

A IPatent claims

1. Grate arrangement, in particular for step swiveling grates, with feeding device, optionally drying and ignition grates and at least one steep grate with an associated flat grate and a subsequent burnout grate, characterized by at least one vortex component step (3) in the step swiveling grate.

2. Grate arrangement according to claim 1, characterized in that the vortex components (3; 3) are designed such that at least some grate bars have blow-out openings (8) for air or another combustion carrier,

AI 3. Grate arrangement according to claim 2, characterized in that high-speed nozzles blow out perpendicular to the flat grate plane.

4. Grate arrangement according to one of claims 2 or 3, characterized in that a plurality of rows of nozzles (8; 8; 8) are provided across the flat grate (9, 10).

5. Grate arrangement according to one of claims 2 to 4, characterized in that the nozzles or Düsen¬ rows are mounted within the pivotable flat grate of the pivoting grate step and are thus themselves pivotable.

6. Grate arrangement according to one of claims 2 to 5, characterized in that the nozzles are designed for additional blowing out of additives or dust-like fuels.

7. Grate arrangement according to claim 6, characterized in that the nozzles for blowing out adsorbents, in particular lime, are formed.

8. Grate arrangement according to one of claims 2 to 7, characterized in that the nozzle axes are set at an angle to one another.

9. Grate arrangement according to one of claims 2 to 8, characterized in that the nozzles consist of Sicromal tube.

10. Grate arrangement according to one of claims 2 to 9, characterized in that the nozzles in the central part of the grate bars - seen over grate bar length - are arranged.

11. Grate arrangement according to one of claims 2 to 10, characterized in that the diameter of the nozzles (8) is 2 to 10 mm.

12. Grate arrangement according to one of the preceding claims, characterized by additional air outlet from the air distribution box (7; 7) under the grate steps along the grate flanks via the gaps formed between them in the firebox.

13. Grate arrangement, in particular as a multi-stage feed grate with fixed and cooled grate bars according to claim 1 for the combustion of hospital waste and special waste, characterized by the arrangement of the nozzle rows in the fixed flat grate.

14. Grate arrangement according to claim 13, characterized in that the nozzles are designed closable.

15. Grate arrangement according to one of claims 13 to 14, characterized in that the nozzles can be closed by a suitable cylinder tappet by translational axial displacement.

16. Grate arrangement according to claim 15, characterized in that the nozzle tappets sit on them common rakes, which are also translationally displaceable.

17. Grate arrangement according to one of the preceding claims, characterized in that the grate bars of the flat grate arrangement carry a slag-repellent ceramic layer (1; 60) embedding the swirl nozzles and having a high temperature resistance.

18. Grate arrangement according to claim 17, characterized in that in addition at least in its lower part the steep grate nozzles in slag-repellent ceramic support (60).

19. Grate arrangement according to one of claims 17 or 18, characterized in that the ceramic coating consists of slag-repellent silicon carbide (SiC).

20. Grate arrangement according to one of claims 17 to 19, characterized in that the ceramic pad is stamped auf¬.

21. Grate arrangement according to claim 20, characterized in that the ceramic pad is stamped in the molding box.

22. Grate arrangement according to one of claims 17 to 21, characterized in that the air supply (53) is provided on the underside of the grate bars, the air guide goes longitudinally through the grate bars and the high-speed vortex nozzles seated vertically on top of the grate bar (54).

23. Grate arrangement according to one of claims 17 to 22, characterized in that two rows of nozzles (54; 54) are provided per grate bar.

24. Grate arrangement according to one of claims 17 to 19, characterized in that starting from the grate bar additional, the ceramic material below, lateral rail-like Haiterur.σen (56) are provided. ß 25. Grate arrangement as a swivel arrangement according to one of the

Claims 17 to 24, characterized in that the ceramic support (51) in the region of the vortex nozzles (54) of the flat grate section and the vortex nozzles (59 ') in the lower region. Area of the steep grate section is provided (Fig. 16).