Title of Invention

PLANT FOR THE TREATMENT OF INHOMOGENEOUS RESIDUE

Abstract

In order to make it possible for inhomogeneous residue (IR) generated in a pyrolysis plant to be separated continuously and in as fully graded a way as possible, specially selected components are combined with one anther in an advantageous arrangement. An essential element of the plant is the separation of coarse residue (GR) in a coarse screen (2) and the subsequent separation of the remaining residue (R) in a zigzag separator (6) into a light residue (LR) and a heavy residue (SR) . By means of the plant, in particular, the carbon-containing constituents are separated from the residue (R) . The individual components are mostly designed to be self-cleaning for fault-free operation.

Full Text

Description plant for the treatment of residue The invention relates to a plant for the treatment of inhomogeneous residue from a thermal waste disposal plant, in particular from a pyrolysis plant. EP-A-0,3 02,310 and the company publication "Die Schwel-Brenn-Anlage, eine Verfahrensbeschreibung" ["The low-temperature carbonization incineration plant, a process description"], published by Siemens AG, Berlin and Munich, 1996, disclose, as a pyrolysis plant, a so-called low-temperature carbonization incineration plant, in which essentially a two-stage process is carried out. In the first stage, the waste delivered is introduced into a low-temperature carbonization drum (pyrolysis reactor) and is carbonized at low temperature (pyrolysed). During pyrolysis, low-temperature carbonization gas and pyrolysis residue occur in the low-temperature carbonization drum. The low-temperature carbonization gas is burnt, together with combustible parts of the pyrolysis residue, in a high-temperature combustion chamber at temperatures of approximately 1200°C. The waste gases obtained at the same time are subsequently purified. The pyrolysis residue has a large proportion of incombustible constituents which are composed essentially of an inert fraction, such as glass, stones or ceramic, and of a metal fraction. The latter comprises a ferrous fraction and a non-ferrous fraction. It is known to separate the individual fractions of the incombustible constituent from one another and to deliver them, if possible to a great extent fully graded, for reutilization. For separating and sorting the residue, it is necessary to have a plant for the treatment of residue, which is capable, in a continuous process, of separating the highly inhomogeneous pyrolysis residue occurring during the pyrolysis process. For ecological reasons, the aim is, in particular, to achieve as complete a separation as possible of the combustible carbon-containing constituents which can, for example, be utilized for energy purposes. The quantity of residue to be dumped on a tip is thereby kept as small as possible. Due to the high inhomogeneity of the residue, which has pronounced differences as regards its material composition, its size and the geometry of its residue fragments, it is essential to co-ordinate the individual components of the plant with one another, in order to ensure that the plant operates continuously and reliably, and in order to avoid a breakdown of the plant caused by components which may have become blocked. The object on which the present invention is based is to specify a plant for the treatment of inhomogeneous residue, which ensures reliable and continuous separation of the residue, without blockages of individual components occurring. The object is achieved, according to the invention, by means of a plant for the treatment of inhomogeneous residue from a thermal waste disposal plant, in particular from a pyrolysis plant, a) with a coarse screen, to which the inhomogeneous residue can be supplied, and b) with an air separator for a residue separated from the coarse residue of the inhomogeneous residue in the coarse screen, the air separator following the coarse screen and having a zigzag-shaped duct through which air is capable of flowing, with an upper outlet for light residue and with a lower outlet for heavy residue. The coarse screen serves for separating coarse residue from the inhomogeneous residue. The remaining fine residue is separated into a light residue and a heavy residue in the air separator which is also known as a zigzag separator. The prior separation of the coarse residue is enormously important for the operating capacity of the air separator, since coarse residue may become jammed in the duct of the air separator. The fine residue introduced into the zigzag separator has a largely homogeneous size distribution. In order to separate the heavy residue from the light residue, air flows at a suitable flow velocity through the duct from the lower outlet towards the upper outlet. Depending on the flow velocity and the specific gravity of the individual residual fragments, the light residual fragments are carried by the air towards the upper outlet, whereas the heavy residual fragments fall downwards. A decisive advantage of the zigzag-shaped design is that even sheet-like heavy residual fragments, such as, for example, crown corks, are reliably separated. In order to ensure particularly reliable separation of course residual fragments in the coarse screen, without the risk of blockage, the coarse screen preferably has a rod which is wound to form a spiral and which extends in the direction of its spiral axis and can be rotated about the latter. In addition, it advantageously has an aligning device for the alignment of elongate solid fragments, the said aligning device being arranged in front of the spiral and opening into the interior of the latter. The aligning device is designed, in particular, as a drum. A coarse screen designed in this way is referred to as a spiral screen. The spiral screen is described in the German Patent Application bearing the official file number 198 23 018.4. The spiral screen may also have a plurality of rods which are arranged in the form of a spiral or part-spiral and which, for example, commence in each case at the drum end of the aligning device and are arranged so as to be offset relative to one another. The part-spirals preferably do not have a complete turn, but preferably possess an angle of rotation smaller than 180°. In a preferred development of the plant, the upper outlet has connected to it a centrifugal screen, in which a rotor is arranged in a housing and a sheet-like screen is arranged between the rotor and housing. As a result of the rotational movement of the centrifugal screen, the light residual fragments supplied to it are thrown outwards in the direction of the screen due to the centrifugal acceleration. The screen ensures separation into two fractions of different grain sizes. In order to make it possible for residual fragments to be comminuted in the centrifugal screen, battens are advantageously fastened to the rotor. Preferably, the centrifugal screen has a balling zone and a grinding zone, the sheet-like screen being arranged around the rotor in the region of the grinding zone. The grinding zone, in particular, follows the balling zone. Both the balling zone and the grinding zone have battens in an advantageous embodiment. In the balling zone, for example sheet-like aluminium foils are shaped into small balls, so as to avoid clogging screen holes of the screen with sheet-like aluminium foils. In the grinding zone, in particular carbon-containing constituents are comminuted with the aid of the battens and can then pass through the screen. An essential advantage of the combination of coarse screen, zigzag separator and centrifugal screen is that a large proportion of the carbon-containing residue constituents is separated, these being utilized thermally, for example in a combustion chamber. In a further preferred embodiment, the lower outlet has connected to it an air separator drum, through which air is capable of flowing and which is mounted rotatably about its longitudinal axis and on the inner wall of which drivers are arranged. The heavy residue is stirred up in the air separator drum, so that light residue still adhering is released. Air flows through the air separator drum towards the lower outlet of the zigzag separator, so that the light residual fragments are entrained and carried upwards in the zigzag separator. Furthermore, a separating device for separating the residue into an inert fraction and into a ferrous and non-ferrous fraction is advantageously connected to the lower outlet and, in particular, after the air separator drum. The heavy residue, which is largely freed of carbon-containing dust constituents by the preceding components, is supplied to the separating device, so that virtually fully graded sorting is then possible. Any carbon-containing residues still present are mainly contained in the inert fraction. In order to recover the carbon constituents which have remained, in a preferred embodiment the separating device has an inert screen for the further screening of the inert fraction. By means of the latter, a fine and relatively carbon-rich fraction is separated and is supplied, for example, for further inert purification in order to separate the carbon which is still present. In a preferred version, the inert screen used is a screen designated as a chain screen, such as is described in the German Patent application bearing the official file number 198 23 019.2 and entitled "Trennvorrichtung und Verfahren zum Trennen von Feststoff" ["Separating device and method for the separation of solids"], to which reference is hereby made. The chain screen described in it is designed essentially as a continuously rotating lattice with fall-through orifices for the solids. Other exemplary embodiments, additional details and advantageous refinements of the invention are explained in more detail with reference to the drawing in which, in each case illustrated diagrammatically: Figure 1 shows a diagram of the plant for the treatment of residue, Figure 2 shows a coarse screen designed as a spiral screen, Figure 3 shows a centrifugal screen, Figure 4 shows an air separator drum, Figure 5 shows an inert screen designed as a chain screen. According to Figure 1, an inhomogeneous residue IR is fed to a coarse screen 2 in a plant for treatment of residue. The inhomogeneous residue IR is preferably pyrolysis residue from a pyrolysis plant. In the coarse screen 2, the inhomogeneous residue IR is separated into a residue R and a coarse residue GR. Its coarse residue fragments are designed, for example, to be larger than 200 mm, are collected and are transported away, as required. The coarse screen 2 is preferably designed as a spiral screen, as illustrated in Figure 2. After the bulky constituents have been separated, the residue R is supplied, via a cellular-wheel sluice 4 and via a feed conduit 18, to an air separator designated as a zigzag separator 6. The zigzag separator 6 is designed as a zigzag-shaped duct 8 which extends essentially in the vertical direction and which has a plurality of bends 10. The zigzag separator 6 possesses a lower outlet 12 for heavy residue SR and an upper outlet 14 for light residue LR. Air L flows through the said zigzag separator from its lower outlet 12 to its upper outlet 14. The cellular-wheel sluice 4 prevents an air leakage stream out of the zigzag separator 6 from branching off towards the coarse screen 2 via the feed conduit 18. The light Residue LR is entrained to the upper outlet 14 by the airflow, whereas the heavy residue SR settles towards the lower outlet 12. An abrupt change in direction of the flow direction of the air L takes place at each of the bends 10, so that the residue R entrained by the air L is exposed to radial forces. As a result, heavy residual fragments SR impinge, as a rule, against the walls of the duct 8. In particular, sheet-like heavy residue fragments SR, the flat side of which is initially aligned with the air direction and which are therefore first carried along by the air L, despite the fact that their specific gravity is too high, change their alignment with the flowing air L at the bends 10 and fall downwards. By means of the zigzag separator 6, in particular, dust-containing and carbon-containing constituents are separated as light residue LR. Impurities which the light residue LR still possesses are light metal or aluminium sheets and fluff or wire fibres. The light residue LR is separated from the air L in a cyclone 20. This air is subsequently purified in a waste-air filter 22 and can then be discharged into the environment or be used as combustion air for a combustion chamber provided in the pyrolysis plant. The light residue LR separated in the cyclone 20 is supplied via a further cellular-wheel sluice 4 to a centrifugal screen 24. In this, the impurities are separated from the carbon-containing dust constituents and supplied to an air separator drum 26. Moreover, in the centrifugal screen 24, larger carbon-containing residue constituents are comminuted and, together with the carbon-containing dust constituents, are diverted as fine residue FR, together with the fine residue FR recovered from the waste-air filter 22, and, for example, supplied as fuel to a combustion chamber. In the air separator drum 26 which is connected to the lower outlet 12 of the zigzag separator 6 and to the centrifugal screen 24, the heavy residue SR is circulated, so that light residue constituents LR adhering to the heavy residual fragments are separated. Air L flows through the air separator drum 26 in the direction of the zigzag- separator 6 and entrains the light and separated residue constituents LR into the zigzag separator 6. The heavy residue SR from the air separator drum 26 is supplied to a separating device 28. In this, separation into a ferrous fraction FE, an inert fraction I and a non-ferrous fraction NE is carried out. The inert fraction I is supplied to an inert screen 30, in which it is separated into a coarse inert fraction GI and a fine inert fraction FI. The inerts of the fine inert fraction FI have, for example, a size of up to a few centimetres and, under certain circumstances, are highly carbon-rich. The fine inert fraction FI is preferably supplied for further inert purification, where the carbon-containing constituents are separated. The inert screen 3 0 is designed, in particular, as a chain screen, as illustrated in Figure 5. The plant described for the treatment of inhomogeneous pyrolysis residue IR makes it possible, by virtue of the special design of the individual constituents and their highly expedient arrangement in relation to one another, to achieve substantial separation of the carbon-containing fragments from the remaining residue which can be separated with a high degree of purity, and with fully graded sorting, into an inert fraction I, a ferrous fraction FE and a non-ferrous fraction NE. These useful materials can be reutilized in a suitable way without any further purification. Figure 2 shows a coarse screen 2 which is designed as a spiral screen and which comprises an aligning device in the form of a drum or rotary tube 32. The latter is inclined relative to the horizontal. A feed device 36 for residue R is arranged at one end of the said coarse screen and at its opposite end is fastened a spirally wound rod 3 8 which forms a spiral 40. The spiral 40 is approximately in alignment with the rotary tube 32, so that the diameter of the rotary tube 32 and that of the spiral 40 are approximately equal. At the same time, the longitudinal axis 41 of the rotary tube 32 coincides with the spiral axis 42 of the spiral 40. The rotary tube 32 is mounted rotatably and can be set in rotation via a drive which is not illustrated in any more detail. The spiral 40 fastened to the said rotary tube also rotates together with the latter. According to Figure 2, this spiral has five turns. The distance between two adjacent turns is preferably about 180 mm. The spirally wound rod 38 consists of a robust material and, in particular, is metallic. It is, for example, a round iron bar or a steel tube. The spiral 4 0 is fastened on only one side, specifically to the rotary tube 32. Its spiral end facing away from the rotary tube 32 is free of fastening means and is not supported. The spiral 40 will therefore bend towards its unfastened end due to its own weight. The spiral 40 may also be fastened on both sides. It is preferably bent. The inhomogeneous residue IR is fed via the feed device 36 and, on account of the inclination of the rotary tube 32 and because of the rotational movement, is transported in the conveying direction 44 towards the spiral 40. In the latter, the coarse residue GR is separated from the remaining residue R, in that only the coarse residue GR is transported further by the spiral 40. An essential advantage of the coarse screen 2 having a spiral 40 is to be seen in that even coarse residue GR which flows sluggishly is transported in the conveying direction 44 in a simple way as a result of the rotational movement. By virtue of the rotational/movement of the rotary tube 32, elongate residual /fragments 46 are aligned in a conveying direction (44) so that they are guided, approximately parallel to the spiral axis 42, into the interior of the spiral 40. This reliably avoids the situation where elongate residual fragments 46 enter the spiral 40 perpendicularly to the spiral axis 42 and fall through the spiral. Only fine residue R can therefore fall through the latter, and this is collected in a first collecting container 47 and, if appropriate, transported away. Coarse residue GR is led through the spiral 40 and at its end falls into a second collecting container 48 and is likewise transported away, as required. Instead of the collecting containers 47, 48, conveying devices, such as conveyor belts or conveying worms, may also be provided, in order to transport the residue R, GR away continuously. An essential aspect of the coarse screen 2 is the bending of the spiral 40, as a result of which the distance between two successive turns changes during the rotational movement. A residual fragment R which has become jammed in the spiral 4 0 rotates together with the latter and is raised. At the same time, the distance between the turns widens, so that the residual fragment R can fall down. The spiral or coarse screen 2 is therefore designed to be largely self-cleaning. Figure 3 illustrates a centrifugal screen 24. This has a rotor 52 which is rotatable about an axis of rotation 50 and which is arranged in a housing 54. The light residue LR separated in the cyclone 20 is supplied to the centrifugal screen 24 from above via a feed orifice 56. The rotor 52 is initially of cylindrical design in the upper region and subsequently tapers downwards in the manner of a cone. Battens 58 are arranged on the rotor 52 obliquely to the axis of rotation 50. Arranged around the rotor 52 is an inner housing 60 which is adapted approximately to the geometry of the rotor 52. The inner housing 60 is designed, in the region of the cone-like rotor 52, as a screen 61 with screen holes 62. The light residue LR supplied is deflected radially outwards as a result of the rotational movement of the rotor 52 and by guide plates 64 mounted on that end face of the rotor 52 which faces the feed orifice 56. The light residue LR flows from there downwards in the gap formed between the rotor 52 and inner housing 60. The said residue, at the same time, passes through a balling zone 66 which is formed in the region of the cylindrical design of the rotor 52 which is followed by a grinding zone 68. The light residue LR usually has carbon-containing residual fragments of a size of a few millimetres. It may, however, also have larger carbon-containing solid fragments up to a size of a few tens of millimetres and be contaminated with light sheet-like metal fragments, fluff and fine conductor wires. In the balling zone 66, the impurities are shaped or comminuted into small ball-like particles by means of the rotational movement and the battens 58. In the grinding zone 68, in particular, the larger carbon-containing residual fragments are ground. The small constituents of the light residue LR which have been fed are separated outwards through the screen holes 62, together with the ground-down carbon-containing constituents, and leave the centrifugal screen 24 as carbon-containing fine residue FR. The balled impurities are essentially carbon-free, have larger dimensions than the screen holes 62 and leave the centrifugal screen 24 as light residue LR. The decisive advantage of the centrifugal screen 24 is to be seen in that the balling zone 66, and, in particular, the destruction of elongate fluff, prevent the screen 61 from being clogged, and in that a carbon-containing fraction is effectively-separated as a fine residue FR. Figure 4 shows a section through an air separator drum 26. The air separator drum 26 is rotatable about a drum axis 70 and has on the inner wall of its drum 72, for example, hook-shaped drivers 74. By means of the drivers 74, the heavy residue SR fed into the air separator drum 26 is raised and subsequently falls down again. As a result, light residues LR, which adhere to the heavy residual fragments SR, are released from the latter and are entrained to the zigzag separator 6 by the air flowing through the air separator drum 26. Figure 5 shows a perspective illustration of an inert screen 3 0 designed as a chain screen. It has two deflecting rollers 82 which are spaced from one another and around which two moving belts 84 running parallel to one another rotate. The running direction of the moving belts 84 corresponds to the conveying direction 86 for a residue R fed onto the inert screen 30, in particular for the inert fraction I separated in the separating device 28. Transverse brackets 88 are mounted vertically on the moving belts 84 transversely to the conveying direction 86. The said transverse brackets are fastened, in each case on their end faces, to the narrow-band moving belts 84, for example by means of a welded joint. Arranged between two successive transverse brackets 88 are longitudinal brackets 90, only three of which are shown by way of example. The longitudinal brackets 90 are preferably arranged perpendicularly to the transverse brackets 88 and are fitted into two successive transverse brackets 88. The longitudinal brackets 90 are fastened to one of these two transverse brackets 88. Arranged on the end face of the longitudinal brackets 90 which faces away from the moving belts 84 are battens 92. These are of step-shaped design, successive battens 92 overlapping one another. Transverse brackets 88 and longitudinal brackets 90 form elevations on the moving belts 84, the height of the longitudinal brackets 90 and that of the transverse brackets 88 corresponding essentially to one another. The battens 92 mounted on the longitudinal brackets 90 project beyond the transverse brackets 88. According to Figure 1, the deflecting rollers 82 are designed as cylinders. Alternatively, a separate pair of deflecting rollers 82 may be provided for each moving belt 84. For a drive which is as free of slip as possible, the deflecting rollers 82 are designed, for example, as gearwheels which engage into corresponding tooth orifices in the moving belt. The moving belt 84 is produced, for example, from plastic and preferably designed as a chain with metallic chain links. Since the moving belts 84 are designed to be narrow-band, not sheet-like, there are formed between the moving belts 84 fall-through orifices 94 which are delimited essentially by the transverse brackets 88 and the longitudinal brackets 90. The area spanned by the transverse brackets 88 and longitudinal brackets 90 acts as a screen orifice or as a screen surface 96. The residue R is fed in a feed region and is transported in the conveying direction 86. In the feed region, an impermeable bottom 98 is arranged directly below the upper portion of the moving belts 84. The bottom 98 has adjoining it a first conveying device 100 for a separated fine inert fraction FI, which is illustrated as a chute running obliquely. Alternatively, it may be designed as an active conveying device in the form of a conveyor belt or a conveying worm. A cleaning rake 102 with tines 104 is provided below the moving belts 84, in particular at the reversal point of the front deflecting roller 82. The cleaning rake 102 is mounted rotatably about its longitudinal axis, as indicated diagrammatically by the arrow 106. The residue R applied to the inert screen 30 is separated into a fine inert fraction FI and a coarse inert fraction GI. At the same time, the maximum size of the fine inert fraction FI corresponds to the maximum extent of the screen surfaces 96. Due to the arrangement of the impermeable bottom 98, the said fine inert fraction first collects, in the feed region, in a kind of screen box which is formed by the longitudinal brackets 90, the transverse brackets 88 and the bottom 98. The accumulated fine inert fraction FI is pushed by the transverse bracket 88 as far as the end of the bottom 98, where it falls through the fall-through orifices 94 onto the first conveying device 100 arranged there. Coarse inert fragments GI, the dimensions of which are larger than those of the screen surfaces 96, remain lying on the longitudinal and transverse brackets 88, 90, are transported further as far as the end of the inert screen 30 and there fall, for example, into a second conveying device which is not illustrated in any more detail. Residual fragments R having unfavourable dimensions may become jammed between two successive transverse brackets 88. As soon as these transverse brackets 88 arrive at the deflecting roller 82 located on the end face, the distance between the two transverse brackets 88 widens and the jammed residual fragment falls out. Thus, by virtue of the design with the rotating moving belts 84, the inert screen 30 automatically removes residual fragments R which are jammed between transverse brackets 88. Jamming is not possible between the longitudinal brackets 90, since the battens 92 mounted on the longitudinal brackets 90 overlap these. The distance between two battens 92 is therefore shorter than that between two longitudinal brackets 90, so that residual fragments R can be jammed only between the battens 92. A residual fragment R jammed between two battens 92 arranged next to one another is entrained as far as the cleaning rake 102 and is released there with the aid of the tines 104. In this case, the tines 104 engage into the interspaces formed by the longitudinal brackets. The inert screen 30 is therefore designed to be self-cleaning even for residual fragments R jammed between the battens 92. Other advantageous embodiments of the inert screen 30 may be gathered from the German Patent application already mentioned, bearing the official file number 198 23 019.2, to which reference is hereby made as an integral part of this description. The same applies to the coarse screen 2, the special design of which may be gathered from the German Patent application bearing the official file number 198 23 018.4. WE CLAIM 1. Plant for the treatment of inhomogeneous residue (IR) from a thermal waste disposal plant, in particular from a pyrolysis plant, comprising a coarse screen (2) for separating the inhomogeneous residue (IR) into coarse residue (GR) and residue (R) said coarse screen connected via a feed conduit (18) to an air separator for the residue (R), the air separator (6) having a zigzag-shaped duct (8) through which air (16) is capable of flowing, with an upper outlet (14) for light residue (LR) and with a lower outlet (12) for heavy residue (SR). 2. Plant as claimed in Claim 1, in which the upper outlet (14) has connected to it a centrifugal screen (24), in which a rotor (52) is arranged in a housing (54) and a screen (61) is arranged between the rotor (52) and housing (54). 3. Plant as claimed in Claim 2, in which battens (58) are fastened to the rotor (52). 4. Plant as claimed in Claim 2 or 3, in which the centrifugal screen (24) has a balling Zono (66) and a grinding zone (68), the screen (61) being arranged around the rotor (52) in the region of the grinding zone (68). 5. Plant as claimed in one of the preceding claims, in which the lower outlet (12) has connected to it an air separator drum (26), through which air (L) is capable of flowing and which is mounted rotatably about its longitudinal axis and on the inner wall of which drivers (74) are arranged. 6. Plant as claimed in one of the preceding claims, in which a separating device (28) for separating the residue (R) into an insert fraction (I) and into a metal fraction, in particular a ferrous fraction (FE) and a non-ferrous fraction (NE), is connected to the lower outlet (12). In order to make it possible for inhomogeneous residue (IR) generated in a pyrolysis plant to be separated continuously and in as fully graded a way as possible, specially selected components are combined with one anther in an advantageous arrangement. An essential element of the plant is the separation of coarse residue (GR) in a coarse screen (2) and the subsequent separation of the remaining residue (R) in a zigzag separator (6) into a light residue (LR) and a heavy residue (SR) . By means of the plant, in particular, the carbon-containing constituents are separated from the residue (R) . The individual components are mostly designed to be self-cleaning for fault-free operation.

Documents:

in-pct-2000-503-kol-granted-abstract.pdf

in-pct-2000-503-kol-granted-assignment.pdf

in-pct-2000-503-kol-granted-claims.pdf

in-pct-2000-503-kol-granted-correspondence.pdf

in-pct-2000-503-kol-granted-description (complete).pdf

in-pct-2000-503-kol-granted-drawings.pdf

in-pct-2000-503-kol-granted-examination report.pdf

in-pct-2000-503-kol-granted-form 1.pdf

in-pct-2000-503-kol-granted-form 18.pdf

in-pct-2000-503-kol-granted-form 2.pdf

in-pct-2000-503-kol-granted-form 26.pdf

in-pct-2000-503-kol-granted-form 3.pdf

in-pct-2000-503-kol-granted-form 5.pdf

in-pct-2000-503-kol-granted-form 6.pdf

in-pct-2000-503-kol-granted-gpa.pdf

in-pct-2000-503-kol-granted-priority document.pdf

in-pct-2000-503-kol-granted-reply to examination report.pdf

in-pct-2000-503-kol-granted-specification.pdf

in-pct-2000-503-kol-granted-translated copy of priority document.pdf