EP1001218A2 - Water-cooled combustion grate, as well as process for incinerating wastes on it - Google Patents

Abstract

The burner grill has stacked, water-cooled grill plates extending over part or all of the width of the grill path and each forming a grill stage. At least every second grill stage is movable and has primary air delivery openings (25) via which dosed primary air can be fed to the fire individually or zonally. The burner grill consists of a combination of a forward feed grill (30) and a backward feed grill (31). An Independent claim is also included for a method of burning rubbish.

Description

The invention relates primarily to a water-cooled combustion grate for waste or incineration. Secondly, the invention relates to a Process for incinerating waste or trash on such incineration grate.

Burning grates for the combustion of rubbish are in many different Executions known. Of a special type of combustion grate is the so-called thrust combustion grate, which has moving parts includes that are capable of performing strokes, thereby causing the firing material to open the rust is promoted and stoked. Basically, the feed of to distinguish the return grids. At first the kiln is in Conveyed forward direction for the loading of firing material, on the latter in the reverse direction to it, being in the forward direction due to the strong incline of Reverse grate rolls down due to gravity alone.

The best way to get such a conventional feed grate imagine when you see an ordinary tiled roof. The individual bricks then represent the individual so-called grate bars of the feed grate represents, while a horizontal row of bricks one horizontally extending row of grate bars, which together each form a single grate. Each grate level overlaps the next lower one arranged. The typical inclination of a combustion feed grate is about 20 degrees, but can also be larger or smaller. At a Such feed grate is now every second grate level and the intermediate grate steps are mechanically movable. A mechanical one Drive device ensures that every such second grate level can perform a stroke, which is that these grate steps in the direction of fall their inclination to be moved back and forth collectively. So that is achieved that the burning garbage lying on the moving grate at a high Residence time of 45 to 120 minutes slowly transported and also relocated and evenly distributed on the grate. At the top of the grate the moving grate is loaded with rubbish. In this so-called loading area the incoming garbage is initially affected by the garbage Heat radiation dried. This is followed by an area on the feed grate, in which gassing sets in, namely the solid components of the refuse change to the gaseous state and release energy. It then follows a primary combustion zone and then a burnout zone.

Compared to the moving grate, the moving grate is with a tiled roof to compare with reverse slope. It brings the advantage of being direct embers lying on the grate from the collectively moved grate steps is pushed back to the beginning of the grate, while the higher layers of the combustion bed roll down in the general direction of transport. From the start of rust to his At the end the primary combustion extends overlapping. This intense, Garbage fire starting at the beginning of the grate is an essential feature of a moving grate. It is created by already burning garbage components with the upward conveying effect of the grate with not yet ignited Parts of the firing material are brought together and mixed, creating a zone very high temperature with high combustion intensity already at the beginning of the grate is produced. The stoking movement consists on the one hand of the natural downward movement of the firing material due to gravity and the opposite acting pushing motion of the grate. With a sliding grate you can generate a certain buffer effect against fluctuations in the calorific value of the fired material, by tearing off the ignition or running away the fire Towards the end of the grate is reliably prevented. Such return grids provide an evenly high burning layer without holes that covers the rust would leave and thus lead to its thermal wear.

The feed grids inclined downwards in the forward direction on the one hand and return grids on the other hand have been known for decades and have as Air-cooled grids, which are made up of cast iron grate bars, are large Distribution found in waste incineration plants. In recent years However, water-cooled gratings have prevailed because they separate the Cooling function from the primary air supply enable what the air-cooled Rusting is not the case because the primary air there also takes on the cooling function got to. Such a water-cooled combustion grate goes by name from EP 0'621'449. Thanks to the water cooling, the grids can be placed on one much lower operating temperature, which is their wear dramatically reduced. The primary air supply can continue because the primary air from the Cooling function is relieved, local and time very fine to the actual need of fire can be adjusted by targeting through a number of feed openings is blown. By making the water-cooled grids out of wide grate plates be built up, which may be across the entire width of the Rostbahn extend and thereby a whole series of conventional cast iron grate bars replace, it is also possible to greatly simplify the rust constructively and the Practically eliminate rust diarrhea. So these hollow grate plates can replace individual conventional grate bars, or two or more, yes, even a whole row is advantageous, so that a grate plate over the extends across the entire width of a grate track. The low operating temperature of the grates allows finally, even the individual movable grate plates, especially if these extend across the entire width of the grate track, with individual, to move drive means arranged directly under the grate plate. From the EP 0'874'195 a water-cooled sliding combustion grate has become known, at which the grate plates are individually driven, and how it is in the present Invention can be used. Depending on the installation direction and inclination such a grate can be designed as a feed or return grate. Such water-cooled feed or return grids allow by means of their additional regulation options, their operation much finer to just that adapting moving fire and taking into account the various influencing factors to take.

A combustion air supply defined at any time and at any location on the grate is the most important prerequisite for the operation of a waste furnace, which should have the lowest possible emissions. Reaching this goal is becoming more and more difficult in practice because of the quality of the refuse in the course of the operating life designed for at least 20 years a waste incineration plant varies. In addition to the basic physical and chemical composition of the garbage it is especially the very widely varying calorific value of the refuse, which causes problems. Rose the Calorific value just a few years ago as a result of commercial waste and sorting of difficultly flammable materials such as green waste and compostable Substances continuously to approx. 12,000 kJ / kg, mainly because of the plastic components, which has risen steadily, so the transition brought to the targeted Elimination of the plastics, the calorific value down to values around 8,000 kJ / kg. The plastics are increasingly used as primary energy substitutes in special Sorting and processing plants extracted beforehand. In addition, the Waste producers are encouraged to, for example, levy waste fees Reduce the amount of waste. They do this by sorting the garbage and taking it Triage at home. Glass goes into the glass disposal for recycling, Wood in bulky goods, paper and cardboard is also recycled, also for example PET bottles. All of these measures resulted a drastic reduction in calorific values. However, it is conceivable that through further measures in the future will increase the calorific values again. Ultimately It depends not least on the course of further technical development which one Waste will accumulate in, for example, 10 years, and in which Quantity. What ultimately ends up in the waste incineration plants is also depending on the behavior of the waste generator, which in turn is influenced of political measures, in particular the fee policy in waste management.

It is fundamentally very difficult to plan a plant today take full account of the garbage quality that changes over time can carry. The object of the present invention is therefore one Water-cooled incineration grate for garbage and a method for the same To specify the company, which in the operation of universal changing rubbish qualities is adaptable, and thus the construction of an incinerator or - machine enables one with everything and everyone to be burned in the future allows optimal combustion to be carried out, with only a minimal Slag portion with as much inert material quality as possible remains, and one if possible perfect burnout for maximum boiler efficiency with optimal flue gas quality can be achieved.

This task is solved by a water-cooled combustion grate for burning waste, consisting of water-cooled, lying on top of each other Grate plates that cover part of the width of the grate or over the extend the entire width of the grate and form a grate step, at least every second grate stage is designed to be movable, and that of primary air supply openings is penetrated, through which individually or zone-wise metered air can be supplied to the fire, which is characterized in that the combustion grate consists of a combination of a feed and a return grate.

a) das ankommende Brenngut auf dem Vorschubrost mittels individueller Steuerung der Hublänge und Hubfrequenz der einzelnen Rostplatten zu einem gleichmässigen Brennbett auseinandergezogen und dann als solches unter Ausbrand der leicht brennbaren Stoffe weiter transportiert wird und schliesslich auf den nachgeschalteten Rückschubrost gelangt,

b) das Brenngut auf dem nachgeschaltelten Rückschubrost individueller Steuerung der Hublänge und Hubfrequenz der einzelnen Rostplatten so lange geschürt wird, bis ein möglichst vollständiger Ausbrand aller Stoffe erreicht ist.

The object is further achieved by a method for burning garbage on a combustion grate according to claim 1, which is characterized in that

a) the incoming firing material on the feed grate is pulled apart by means of individual control of the stroke length and stroke frequency of the individual grate plates to form a uniform combustion bed and then transported as such with the burning out of the easily combustible materials and finally reaches the downstream sliding grate,

b) the firing material is stoked on the downstream sliding-back grate with individual control of the stroke length and stroke frequency of the individual grate plates until all materials have been completely burned out.

In the drawings, a water-cooled moving grate is referenced as an example shown on its basic structure, how it is for the realization of the Individual drive of the grate levels can be built. Next is a combination of a feed and push-back grate shown. These grids are below described in detail and their function for the procedural Operation is explained.

Figur 1:

Ein Längsabschnitt eines wassergekühlten Schubrostes in einer perspektivischen Ansicht, mit zum Teil entfernten Rostplatten;

Figur 2:

Eine Kombination eines Vorschubrostes mit einem Rückschubrost, von der Seite her gesehen in einem Längsschnitt, schematisch dargestellt;

Figur 3-5:

Verschiedene Phasen im Zug der Verbrennung einer Charge von Kehricht auf einer Kombination eines Vorschub- und eines Rückschubrostes, die hierzu für die Betrachtung herausgegriffen sind;

It shows:

Figure 1:

A longitudinal section of a water-cooled sliding grate in a perspective view, with some of the grate plates removed;

Figure 2:

A combination of a moving grate with a moving grate, viewed from the side in a longitudinal section, shown schematically;

Figure 3-5:

Different phases in the course of the combustion of a batch of rubbish on a combination of a feed and a return grate, which are selected for this purpose;

The basic structure of this thrust combustion grate with its essential elements can be seen from Figure 1, regardless of whether it is in the individual case is a moving grate or a moving grate. Here is a longitudinal section a moving grate shown in a perspective view as he presents itself during construction, where individual grate plates are still missing and thus the view of the substructure is clear. With a similar structure Sliding grate is reversed. Two vertically standing, parallel to each other side steel walls 1,2 are here a number of spacer tubes 3.4 stably connected to each other. These distance tubes 3,4 run across the grate and extend on two different ones Level over the clear width between the two side steel walls 1,2. The two steel walls 1,2 left and right of the grate can consist of several Steel plates or parts consist of each other in an appropriate manner are screwed. The spacer tubes 3, 4 penetrate these steel walls a thread on both sides and are by means of cones and nuts 7 firmly screwed to the side steel walls 1,2. The spacer or cross tubes 3 of the upper level also serve as support tubes for those on them stationary grate plates 5. The lowest stationary grate plate 5 lies with its front edge on a fixed between the side steel walls 1,2 welded ejection lip 22, and with its rear area it is hung over the first upper spacer or cross tube 3. Next is one movable grate 6, with its front lower edge on the first, below it lying stationary grate plate 5 rests. Then again lies on her front lower edge of the next higher stationary grate plate 5, and so on. In the example shown, the grate plates therefore each extend over the entire width of the grate track and thus form a grate step. Alternatively, you can but also several such grate plates lying next to one another form a grate step. The individual grate plates are on their bevelled front of primary air slots 25 interspersed with primary air from below the grate the combustion is blown into the firing material. Along the top of the Steel walls 1, 2 run two mutually displaced one another Hollow profiles in the form of square tubes 8.9, the ones at their lower level Are closed by being welded there. These square tubes 8,9 form the side planks of the grate run and limit this in operation Firing bed laterally. They are water-cooled and are going from bottom to top forcibly flowed through by water, so that its interior is always completely with it Water is filled. The individual grate plates 5,6 are made of sheet steel and also designed as a hollow body, which is inevitably made of water are flowed through that their cavity is always completely filled with water and no air bubbles can form inside. All steel sheet parts of the grate, be it the side planks 8.9 or the grate plates 5.6, which with coming into contact with the firing material are therefore on the rear side of the sheet constantly covered by water. So everyone can come into contact with fire Parts are constantly cooled and kept at a stable temperature so that practically no dilations occur. It is therefore not necessary to the side of the Provide any compensation elements. This will rust very simplified in its construction. The stability of the rust construction is essentially achieved by the spacer or transverse tubes 3.4, which in two brace the two outer steel walls 1, 2 parallel planes and tense up, as has already been described. Between these two Levels of cross tubes 3, 4 run along the grate on both sides thereof Longitudinal center two more hollow profiles in the form of square tubes 10, 11 below and above in some places with the transverse tubes 3, 4 running transversely to them are connected. One of the square tubes, namely the square tube 10, leads from bottom up the cooling water for the grate plates 5,6 while the other Square tube 11 purge air and cooling air for the drives of the movable grate plates 6 feeds. Between these two square tubes running parallel to each other 10, 11 support elements 12 are installed for the movable grate plates 6. For this purpose, these support elements 12 are by means of two bolts 13, 14, which are the two Push through square tubes 10,11, held on them. The square tubes or For this purpose, hollow profiles 10, 11 have welded cross tubes with a such an inner diameter that the retaining bolts 13,14 for the support elements 12 fit into this. The support elements 12 themselves each have a parallel to corresponding rust plate level lying steel roller 15, and left and on the right a steel roller 16, 17 running there in the vertical plane. At the same time a hydraulic cylinder 18 is articulated on each such support element 12, the Piston rod 19 in turn on the underside of the movable it moves Grate plate 6 is articulated. The grate plate itself, which is shown on the here Support element 12 rests, is only indicated here with dashed lines. On its underside it has a central guide groove with which it rests on the steel rollers 16, 17, which when moving the grate plate on the Unroll the bottom of this guide groove. The clear width of the guide groove is chosen so that they are slightly larger than the diameter of the lying steel roll 15, whereby the grate plate from the roller 15 in the transverse direction to the grate track is sufficient is led. To guide the front of the movable grate plate are 8 additional steel rollers 20, 21 attached to the planks. The associated movable grate plate now has such on the front underside Recesses so that a guide surface is formed on each side, which runs parallel to the side surface of the grate plate, but opposite it is set back, and on which these steel rollers 20,21 when moving back and forth unroll. Each movable grate plate thus has one Three-point mounting on the rear in the middle, where the drive is located, is the grate plate guided horizontally and vertically by the corresponding steel rollers 15, 16, 17, and at the front it is guided to the left and right by the steel rollers 20, 21, while with their front lower edge on the next lower stationary one The grate plate rests and slides on it when it is moved back and forth. Your front For this purpose, the lower edge is specially provided with a sliding block made of wear material, which can be replaced from time to time without the actual The grate plate must be replaced. An advantage of the one described here Construction is now that the movable grate plates are precisely guided and there is no more lateral friction because the lateral guidance is set so that between the side edge of the movable grate plate 6 and the adjacent plank 8 a constant short distance is maintained so that no jamming small parts can fall into this slot and at the same time but the slot is so wide that there is no sliding friction. The Because of this precise guidance, the grate plate can no longer tilt, as was still possible with conventional designs. If so far Canting occurred, the plate was simply against the greatly increased sliding friction moved back and forth with great force until the one that triggered the cant Clamp part fell down or out of the slot between the grate plate and plank worked out. Until that happened, however, high sliding friction forces developed a correspondingly large amount of wear. This wear and tear is eliminated with the storage and guidance of the movable grate plates shown here, which increases their service life. Another advantage of the design can be seen in the fact that the forces for actuating the grate plates as a result Guide on steel rollers are considerably smaller than when pure sliding friction is too is overcome. This in turn allows the use of small drive units in the form of compact hydraulic cylinder-piston units, each for individual movable grate plate use such a drive unit is coming. This means that each movable grate plate can be driven individually be what the requirements for driving a geometric as possible Fire does justice. Depending on the combustion process and behavior of the fired goods can be targeted at certain points with small Stroke movements of the grate plates fueled the fire or with larger ones Strokes to be transported on the grate. The constructive solution with the support elements 12 between the longitudinal two Square tubes 10, 11 even allows the replacement of a drive unit during operation of the grate. This is possible because the grate plates 5.6 either extend individually over the entire width of the grate track or in a variant several grate plates are connected together so that they Cover the entire width of the grate track without slits between them and thereby hardly any rust diarrhea occurs, which is due to the ones under the grate Fitters could fall down. In the event that several grate plates become one Grate step can be connected together, for example by screwing them together or welding such individual grate plates together take place, each of which extends over part of the grating track width. In this Thus, two, three or more grate plates arranged side by side can be used can be combined into a single grate level. Remains because of the the entire combustion bed including water cooling the temperature below the Rust in an area that allows you to stay and work under the rust readily possible. Finally, each support element 12 is by means of the bolts 13.14 hung on the square tubes 10.11 so that by knocking out of the rear bolt 13, the entire support element can be tilted backwards can, after which the articulation of the hydraulic cylinder 18 is accessible and this can be easily expanded. In Figure 1 is a longitudinal section Rostbahn shown. The entire rust track often consists of several such sections. For this purpose, the ends of the square tubes 10, 11 and the planks 8, 9 are included Flanges 51,52 equipped so that they are waterproof with the planks and square tubes of the subsequent section can be flanged together. This design allows individual longitudinal sections of a grate track in the Prepare the workshop ready for installation and complete such grate track sections on site assemble quickly. Complicated special transports on the one hand or protracted on-site assembly work is avoided. The Water cooling of the grate plates takes place through connections on the square tube 10, in which cooling water flows from bottom to top. It is based on one open expansion tank, which is, for example, at the level of Dispenser gutter or higher located, through a line by means of a Electric pump pumped down into the square tube 10 and therein at a pressure held by 3-4 bar. Two adjacent grate plates become one in series Cooling circuit switched, since together they always have a constant grate surface form. This is done for two grate plates via a nipple or a sleeve 10 water removed from the square tube running underneath and through a temperature-resistant hose into the first grate plate. In it flows Water forced through a maze that is designed to be nowhere Air bubbles can form, but the entire cavity inside the grate plate is completely filled with water. At the end of the flow channel in Inside the grate plate there is a connection from which a another temperature-resistant hose leads to the second, neighboring grate plate, in which again flows through a flow channel and finally from the end of it leads through a hose into a return pipe that returns itself leads into the open expansion tank and flows into it. For two each Adjacent grate plates is therefore a water connection on the square tube 10 available, and the corresponding cooling water is in each case a separate Return pipe returned to the expansion tank. The square tube 11, however does not carry water, but air at an overpressure that an air pump for the following purpose: For each movable grate plate own drive unit with hydraulic cylinder available. This Hydraulic cylinders are each housed in a tubular jacket, so that between that and the actual hydraulic cylinder have a free space. This Free space is flushed with air from the square tube 11, so that the Pipe jacket forms a rinsing cylinder. This is done at every point of the square tube 11, where a hydraulic cylinder is located, via an air connection tapped from the inside of the square tube, and this air is fed into the Pipe jacket guided, which envelops the hydraulic cylinder as a flushing cylinder. The The tubular jacket is open at the front so that the purge air can flow out again finally reaches the zone below the grate, where it joins with the Primary air mixed. However, the volumes of this purge air are compared to primary air used is negligible and therefore has hardly any influence on the combustion. By rinsing the jacket pipes, the actual ones Hydraulic cylinders and the piston rods leading out of them always kept free of dust and dirt, resulting in a long service life of the drive unit is beneficial. On the other hand, with this air flowing around it becomes natural achieves a cooling effect, which contributes to the hydraulic oil used is never overheated. The area below the grate plates is over the grate track length divided into several underwind zones. Each below one stationary grate plate, a partition is built in, which separates the neighboring ones Separates wind zones practically airtight. In the individual underwind zones is blown in primary air by means of a separate fan blower, which then passes through the primary air slots 25 into the combustion chamber. The The primary air volume can be varied by varying the speed of the individual Fans are regulated. This variability of the primary air supply in the individual rust zones helps to drive a geometric fire by the fire is supplied locally with air in the amount required can be.

Conventional systems that only consist of a pure feed grate or consist of a pure return grate, especially in the borderline cases difficult to handle. For example, consider their behavior when they burn from waste with a particularly high calorific value. Especially with the push-back grate then leads the short and intense one that starts right at the beginning of the grate Fire at an imbalance in the boiler room in relation to the flow of the flue gases. These sweep up along the front boiler wall and simultaneously the rear wall of the boiler is under-loaded. With the sliding grate, the Transport of the fired goods can hardly be accelerated. With the push-back strokes only the embers in the bottom of the burning bed can be pushed back, whereby the upper layer of the burning bed rolls down. So in principle it can only the burning bed is relocated and the transport can only be slowed down. In the case of garbage with a high calorific value, it would be desirable that the fired material after loading if there is a high pile on the opening report of the grate, pulled apart as quickly as possible and on the whole Rust would be evenly distributed beneath the kettle and then a geometric one Fire would be maintained until the burnt out at the end of the grate Slag remained. In practice, however, the refuse burns with a high calorific value mostly far too early and the second part of the grate and the rear boiler part remain under-burdened. The erosion takes place with a significant skew. The push-back grate is therefore more suitable for rubbish with a low calorific value. Here he can use his advantage that the kiln can be rearranged for any length of time and can be stoked, with the embers thrown back again and again until a complete burnout has been achieved.

Conversely, let's look at the situation with a rubbish results in a particularly low calorific value with a moving grate. Here then exists the problem is that when moving the grate steps it is probably a fuel of the Fire is achieved, but at the same time the firing material is always transported becomes faster than one would like. In extreme cases, there is the problem in that the burnout is incomplete because the firing material is on the grate surface to go through quickly.

A combination of a feed grate with a downstream one Reverse grate proves to be a surprising solution for the shown Dilemma. Such a combination of a feed grate is shown in FIG Design described for Figure 1 with a sliding grate of basically the same Design shown from the side. The firing material passes through a Dump channel 26 on a loading chute 27 by a hydraulic cylinder-piston unit 28 is driven and the firing stock as evenly as possible promoted the rust. For this purpose, the feed chute 27 moves slowly forward, continuously Rubbish falls over the edge 29 onto the grate. From the foremost position of the Feeding chute 27 moves it back quickly and starts again if necessary pushing garbage slowly from behind, so that if desired one almost uniform supply of rubbish on the grate is possible. A moving grate 30 with an inclination of 22 ° here forms the first grate area. It exists from eleven stationary and water-cooled grate plates 5 and in between arranged ten movable water-cooled grate plates 6. The movable Grate plates 6 are each with a cylinder-piston unit arranged below the grate plate 18.19 equipped. At the front edge of the grate plates are 5.6 Primary air openings 25 are present, which are formed by pipe sections, which push through the grate plates 5,6 from below. The primary air openings 25 of the first six grate plates 5, 6 are assigned to the primary air zone 32, those of the next eight grate plates 5,6 are fed from the primary air zone 33, and the last seven grate plates 5,6 are supplied with primary air from the primary air zone 34. These different primary air zones 32-34 are separate from each other and additional can target combustion-promoting gases to each of these zones Pure oxygen, for example. Following this feed grate 30, a push-back grate 31 is attached, which has a greater inclination, here 26 °, because the firing material is due to a moving-back grate alone gravity is transported. This sliding grate 31 out in the same way water-cooled stationary 5 and movable arranged therebetween Grate plates 6 are divided into two primary air zones 35 and 36. The special in this entire grate system it is that a feed grate 30 with a Back-sliding grate 31 is combined. Because the grids are water-cooled and in addition, each movable grate is individually movable, both in relation to the respective stroke length as well as in relation to the stroke speed and the frequency of the batches, the firing material lying on the grate can be local and treated separately in terms of time and transported by name and be stoked. In addition, the primary air supply can be regulated zone by zone and the addition of oxygen when required can also be difficult help combustible materials to burn out completely. This rust allows hence a much more universal adjustment of the significant conditions for the Burning out of a certain product to be burned. It can therefore targeted consideration of the calorific values and the composition of the rubbish be taken and optimal burnout can be achieved in any case.

In Figures 3 to 5, a batch of rubbish is in different burning phases shown. First and immediately after loading the Regardless of whether it has a high or low calorific value, the garbage is in Form of a relatively high pile 37 on the foremost part of the feed grate 30, as shown in Figure 3. If it were left here, it would be the calorific value particularly high, a rapid burn-up would take place, but that Fire would be located very one-sided under the boiler. The kettle would become very uneven charged. If, on the other hand, the calorific value were particularly low, this would result there is only a weak fire and the lower layers of the rubbish heap 37 would hardly burn. The solution in both cases is therefore to quickly pull the pile 37 apart so that it has all the feed grate 30 covered with a uniformly high burning bed. For this, the moveable Grate plates 6 operated accordingly. Those at the very beginning of the grate movable grate plates 6 are moved little or not at all, and the further the Grate plates 6 from the beginning of the grate are all the more intense and with larger Strokes are moved until the picture finally results, as shown in Figure 4 is shown. With such a uniformly thick combustion bed 38, primary combustion now takes place completed as optimally as possible. Here can also be very high Burning temperatures can be accepted thanks to the water cooling of the grate pose no problem. The thermal load limits in in no way the throughput of such a water-cooled grate, it is only limited by the rate at which it burns completely. The lower the calorific value of the current firing material, the longer the necessary one Failure to stay on the grate. If necessary, the entire length of the Feed grate 30 stoked with short strokes, so that only a small transport component results until the burnout occurred sufficiently. Then you can in the last part of the feed grate 30, the strokes are extended so that the Almost burnt out firing material via the ejection lip 22 on the downstream Push-back grate 31 is pushed.

What is left of the original batch and strong in volume shrunken firing 39 is now completely on the downstream Push-back grate 31, as shown in Figure 5. Here now offers itself the opportunity to intensely operate this kiln 39 through almost any length of time Stoking to a complete burnout because stoking on one such a push-back grate 31 no direct transport of the combustion material 39 entails. Rather, only the lowest burning layer, the embers, pushed back up to the next grate level. Material that itself above the upper, retracting edge of the stoking grate due to gravity, it rolls further down. Thus, by several Local strokes achieved a rearrangement of the combustible 39. The deep, of the primary air zones 34 and 35 come from layers well supplied with primary air in the combustion bed 39 in higher positions, while the upper ones are not yet complete burned-out layers in the burning bed 39 are plowed in so to speak and thus exposed to the heat and primary air supply, so that they too burn out completely. Gradually, the burned out slag finally falls on End of the push-back grate 31 over the last grate level into a slag collector.

Each individual movable grate plate 6 of both the feed 30 and the sliding grate 31 can be moved individually and as required whereby the current firing situation is optimally taken into account can. Between the stoking and transport function can in particular Feed grate 30 can be played. The following can be used as tax parameters Temperatures of the returns of the water cooling circuits of the individual grate levels 5,6 serve, together with the optical detection of the fire by means of pyrometers. Another parameter, in addition to the local and temporal transport and the stoking forms the primary air supply. The amount of supplied air can be varied as needed. In addition, the Primary air can be enriched with pure oxygen, or it can be oxygenated enriched air is also blown into primary air zones 32-36. The primary air supply pipes that penetrate the grate plates open somewhat above the surface of the grate plates 5,6 and advantageously have an elongated hole Cross section on, with the elongated holes in the direction of the general Extend the transport direction of the grate. This avoids that Excessive slag falls through the grate through these pipes. The mouths 25 of these primary air pipes or corresponding primary air supply channels are included Guide elements in the form of, for example, bow-shaped guide plates, the are simply welded onto the top of the grate plate. The top section the baffle is V-shaped in cross section. The bottom of these baffles impacting primary air jet is therefore divided by the baffles, deflected laterally, its speed slows and the air swirls. The effect is that the air is diffused into the Firing material penetrates. The air that flows through the primary air outlets arranged in a row 25 flows in, so that the burning bed in its entirety Diffuse width to penetrate, so that the atmospheric oxygen much more homogeneous than before is supplied to the combustion. It becomes, so to speak, the entire burning bed penetrating carpet of air and harmful blow-through can be avoided become. Blow-throughs are primary air streams that localize the combustion bed break through and carry a lot of dust and ashes up into the boiler room, what is very undesirable. At the same time, the bow-shaped baffles cover the mouths 25 in the thrust direction of the grate, so that the firing material is around the guide plates is passed around and does not directly cover the primary air orifices 25.

The combustion therefore takes place in accordance with the method described here of the garbage basically first on a moving grate and then to achieve it optimal burnout on a downstream sliding grate. The system can be designed on a case-by-case basis. In extreme cases it is Feed or retractable grate of very short length and may include just one movable grate. As an important prerequisite for the Operation of the grate is in addition to its combination of feed and return grate also the opportunity to see that the movable grate levels individually can be moved, both in terms of stroke length as also in terms of stroke speed and stroke frequency. Short stroke lengths then cause local agitation without any significant transport effect to pull on the kiln. Of course it is possible to move several grate levels evenly, for example to do this Transport the combustion bed uniformly over an entire length. Finally, the way in which the primary air is supplied is decisive. This can be regulated zone by zone using a separate air blower and finally offers the opportunity to specifically promote combustion in the case of difficultly combustible waste Dosing gases, especially pure oxygen. As a specialty can have certain supply openings in the grate levels similar to primary air supply openings be designed, but designed to be about them burning media, e.g. filter ash or dried sewage sludge, can be introduced into the firing material from below. These feed openings have a larger cross section and through them such substances can be used of a hydraulically operated piston are pressed directly into the combustion bed, so that they are specifically injected directly into the hottest places in the fire can.

The water-cooled combustion grate presented here and with this operated combustion process allows because of the many degrees of freedom a universal adaptation of the combustion to a wide variety of rubbish qualities. Especially the combination of feed and push-back grate proves itself as the key, because only this combination allows the transport and the Varying to vary in a wide band range, so that garbage with high Calorific value is transported quickly and vice versa difficult to combustible waste the burnout zone can be relocated for a particularly long time, much longer than that on a pure infeed or on a backfeed grate, if at the same time new rubbish is added in the initial area of the grate shall be. The air duct with separate zones and covered air outlet openings and the possibility of being able to meter in pure oxygen is one optimal and complete combustion further beneficial.

Claims (10)

Water-cooled incinerator grate for incinerating waste from water-cooled, stacked grate plates (5,6), which overlap extend part of the width of the grate or over the entire width of the grate and each form a grate level, at least every second grate level being movable is executed, and which is penetrated by primary air supply openings (25), through which individually or zone-wise Pirmärluft dosed can be fed to the fire is characterized in that the combustion grate from a combination a feed (30) and a push-back grate (31). Water-cooled combustion grate according to claim 1, characterized in that a feed grate (30) is first arranged in the loading direction, and then a push-back grate (31) with a larger one on the feed grate (30) Tilt is arranged so that it can be fed from the feed grate (30). Water-cooled combustion grate according to one of the preceding claims, characterized in that over the mouths of the primary air supply openings (25) guide elements are arranged on the grate, on which the emerging primary air for the purpose of diffuse distribution and avoidance of Blow through is determined to occur. Water-cooled combustion grate according to one of the preceding claims, characterized in that both the feed grate (30) and the push-back grate (31) each with several separate zones (32-36) with their own Air blowers are assigned, through which primary air passes through the grate from below can be fed into the burning bed. Water-cooled combustion grate according to one of the preceding claims, characterized in that feed channels the feed grate (30) or push through the moving grate (31) through which medium to be burned can be pressed directly into the combustion bed from below through the grate is. A method of burning garbage on a combustion grate according to claim 1, characterized in that a) the incoming firing material on the feed grate (30) is pulled apart by means of individual control of the stroke length and stroke frequency of the individual grate plates (6) to form a uniform combustion bed (38) and then transported as such with the burnout of the easily combustible materials and finally on the downstream Retractable grate (31) b) the firing material on the downstream return grate (31) is stoked by means of individual control of the stroke length and stroke frequency of the individual grate plates (6) until all materials have been burnt out as completely as possible. A method of burning waste according to claim 6, characterized in that aa) in the first grate area, the firing material is pulled apart to form a uniform firing bed (38) by means of individual control of the stroke length and stroke frequency of the individual grate plates (6) of the feed grate (30) there, ab) in the second area of the feed grate (30) the uniform combustion bed (38) is transported so quickly or slowly by means of individual control of the stroke length and stroke frequency of the individual grate plates (6) that the easily combustible materials burn out completely, b) on the downstream sliding grate (31), the materials that have not yet burned out are stoked by means of individual control of the stroke length and stroke frequency of the individual grate plates (6) until they are completely burned out. A method for burning garbage according to one of claims 6 to 7, characterized in that the primary air for the feed (30) and Back-sliding grate (31) supplied separately in zones by separate air blowers and the primary air, if necessary, selectively pure oxygen is metered. Method for burning waste according to one of claims 6 to 8, characterized in that the control of fueling, transportation and zone-by-zone primary air supply and, if necessary, zone-by-zone metering of oxygen depending on at least the temperature of the returns Water cooling of the individual grate plates (5,6) is controlled. Method for burning waste according to one of claims 6 to 9, characterized in that media to be burned via feed channels, which pass through the feed grate (30) or the push-back grate (31), through the grate directly from below into the combustion bed.

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