Indian Patents. 219623:"PROCESS AND DEVICE FOR TREATING A MIXTURE OF SUBSTANCES CONTAINING STRUCTURED CONSTITUENTS AND ORGANIC MATTER"

Title of Invention	"PROCESS AND DEVICE FOR TREATING A MIXTURE OF SUBSTANCES CONTAINING STRUCTURED CONSTITUENTS AND ORGANIC MATTER"
Abstract	A process for treating a mixture of substances containing structured constituents and organic matter, and a device for carrying out this process are disclosed. In accordance with the invention, the mixture of substances is subjected to pulse-type or periodical application of force, so that the formation of flow channels for a leaching fluid or process air in a bulk material may be prevented.

Full Text	The invention relates to a process for treating a mixture of substances containing structured constituents and organ1c matter, in accordance with the preamble of claim 1, and a dev1ce in part1cular for carrying out this process. Such a process is, for example, utilized for treating residual waste matter. In DE 196 48 731 Al a waste matter treatment method is descr1bed, wherein the residual waste matter is treated in a percolator. By such a percolation or extraction, organ1c constituents, inorgan1c substances and in a given case water-soluble fatty acids are leached from the waste matter by an extracting or washing agent. The residue is withdrawn from the percolator and, following a subsequent drying, supplied to combustion or dumped,. It was found that by this process the organ1c substances cannot be removed in the required extent from the residual 'waste matter. The drawbacks of this known waste matter treatment process may be eliminated by the process for treating biolog1cal waste as disclosed in WO 97/27158 Al. In this process a novel percolator is employed wherein the waste matter passes through the reactor in a horizontal direction (longitudinal direction), and a biogen1c reaction is superseded to the percolation process by supplying atmospher1c oxygen (process air). As a result of supplying process air, the cells of the organ1c matter are split open and the l1berated organ1c substances are carried off by the leaching fluid. In order to avoid channel formation within the waste matter and introduce shear forces, an. agitator or circulating apparatus is provided in the reactor, whereby the waste matter is mixed thoroughly in a vert1cal direction (in parallel with the direction of flow of leaching fluid and process air) and also displaced in the direction of transport. It is a drawback in this process that for guiding and mixing the waste matter within the reactor, a considerable expense must be incurred wh1ch substantially influences the investment costs. Such a complex mechan1cal structure also harbors the risk of failure of the installation owing to a malfunction in the transport system of the reactor, so that a comparatively high expense for serv1cing the reactor must be incurred. Such downtimes of the reactor as a result of the necessary maintenance or of a malfunction in the reactor periphery may, however, only be neutralized by providing corresponding buffer spaces wherein intermediate storage of the waste matter during the downtime of the reactor is poss1ble. In DE 196 08 586 Al a rotting process is descr1bed wherein the exposed pit is subjected to pressurized air. In contrast, die invention is based on the object of furnishing a process for treating a mixture of substances containing structured constituents and organ1c matter, and a dev1ce wherein suff1cient decomposition of the organ1c proportion takes place at minimum expense in terms of dev1ce technology. This object is achieved by the features of claim 1 as far as the process is concerned, and by the features of claim 12 as far as the dev1ce is concerned. Through the measures of causing the mixture of substances (for example residual waste matter) containing structured constituents and organ1c matter to pass through the reactor in the absence of any substantial longitudinal and transversal mixing, and of preventing channel formation by applying forces to the mixture of substances wh1ch are directed approximately in parallel with or transversally to the direction of displacement, the reactor may have a substantially more simple construction than in the above descr1bed prior art because it is not necessary to provide an agitator for lateral mixing. The forces are preferably introduced from the peripheral area of the reactor, for example through a suitably designed discharge means or by means of injected gas, preferably pressurized air. In part1cular when pressurized air is used, shear forces are also applied to the bulk material, whereby the surface of the heap material is reorganized and part1cles of the mixture of substances are separated into f1bers. The reactor may be employed as a percolator and dryer without any restructuring or modif1cations becoming necessary. : Upon introduction of the forces preventing channel formation by way of the discharge means, the mixture of substances is preferably circulated at least in part, so that shear forces are introduced due to the conveyor elements bringing about the circulation. The flow management according to the invention makes it poss1ble to design the reactor with a high degree of compactness, wherein it is poss1ble to position all of the feeding and discharging means at the head or bottom portion of the reactor. In a part1cularly preferred embodiment, the forces for prevention of channel formation and the shear forces required for surface reformation and for tearing open the part1cles are applied through a pressure gas, preferably pressurized air, wh1ch is injected into the bulk material (heap material) from the peripheral area of the reactor. By the pressurized air the heap material is partially expandedy so that a surface reformation takes place in the bulk material and'the part1cles are torn open as a result of the introduced shear forces - the mass transfer area for decomposition of the mixture of substances by means of the atmospher1c oxygen and of the leaching fluid is increased. In a part1cularly preferred embodiment, the pressurized air and the process air are supplied through nozzles arranged in the foot portion and/or in the bottom portion of the reactor. In accordance with the invention it is preferred if . the-mixture of substances passes through the reactor essentially vert1cally (in parallel with the direction of gravity) or horizontally, so that the mixture of substances is guided approximately in parallel or in a flow transversal to the process air. In a case where the reactbr is employed as a percolator, the leaching fluid is preferably supplied through a distr1butor in the head portion of the reactor. The pressurized air is supplied at a pressure of more than 2 bar, preferably more than 4 bar, whereas a pressure of 0.5 bar is customarily applied to the process air. The nozzles for introduction of the process air and/or pressurized.air may advantageously be controlled individually, so that a specif1c pressurized air profile may be adjusted across the reactor cross-section. ' The use of pressurized air for introducing shear forces and for preventing channel formation has the advantage of the atmospher1c oxygen required in the bulk material for the aerob1c process being supplied concurrently, so that the pressurized air bas1cally fulfills a twofold function: 1. supplying atmospher1c oxygen for aerob1c decomposition, and 2. introduction of shear forces. In a more simple embodiment the forces for preventing channel format ion. in the bulk material are, for example, supplied through a discharge means arranged at the bottom portion of the reactor. This discharge means may, for example, be a scraper floor installation or a similar conveyor means for discharging the mixture of substances by layers. This variant has the additional advantage of feeding and discharging openings in the bottom portion of the reactor being kept free owing to the advance movement of the discharge means, so that the leaching fluid may exit and pressurized air or process air, respectively, may penetrate into the bulk material. As a discharge means, a worm conveyor carpet, a walking floor, silo filler means etc. may also be used. These discharge means may, of course, a'lso be used' in the above descr1bed embodiment with pressurized air. Inasmuch as the mixture of substances passes through the reactor preferably in the form of layers, the dwell time of the mixture of substances inside the reactor may be determined with high precision in the case of continuous process management, so that the passage times with respect to the biolog1cal decomposition may be optimized. In the solutions named at the outset, only a mean dwell time value could be determined due to the longitudinal and transversal mixing by means of the agitator. The laden process air or the laden pressurized air, respectively, are supplied to a waste gas purif1cation wherein organ1c constituents are separated and the purified air is recycled into the process. The energy balance of the installation may be further improved if the laden leaching agent is supplied to a sewage water purif1cation. The latter may contain a biogas installation wherein conversion of the organ1c matter into biogas takes place. Through energet1c coupling of the l1berated biogas, the process according to the invention may be designed to be largely self-suff1cient as regards energy. In the above descr1bed process management, the mixture of substances containing organ1c matter is subjected to a so-called hydrolysis wherein, through cooperation of air and leaching fluid, the organ1c material is dissolved and acidified as a result of aerob1c, thermophil1c heating by the air and carried off by the leaching fluid. I.e., decomposition of the organ1c constituents takes place as a result of setting a certain humidity and•supplying clean air. Further processing of the mixture of substances provides for drying of the residue in accordance with the invention. Such drying may be effected at minimum energet1c expense by aerob1c, thermophil1c heating of the residue in the reactor. To this end, the mixture of substances may either be subjected to appl1cation of clean air in the reactor, so that by the resulting aerob1c heating water vapor is discharged via the supplied air,' and the residue is dried. Drying and hydrolysis in one single reactor is, however, under the condition of batch-type operation wh1ch should be viable only in smaller installations. In larger-sized installations a separate reactor (dryer) is provided for aerob1c, thermophil1c heating of the residue from hydrolysis. As a matter of fact, these two reactors may also be arranged behind each other in n-fold succession in a single container, so -that several hydrolysis/drying steps may follow in succession. The energy balance of the installation may be further improved if the laden leaching agent of a purif1cation of sewage water is supplied. The latter may contain a biogas installation in wh1ch conversion of the organ1c matter into biogas takes place. Through energet1c coupling of the l1berated biogas, the process according to the invention may be designed to be self-suff1cient as regards energy. It is quite part1cularly advantageous if the solid fraction thus treated is supplied to a compacting step following hydrolysis and/or aerob1c drying. Here the solid matter presenting a certain part1cle diameter is pressed into a predetermined geometr1cal shape, for example pellets or briquets.. This compacting step results in further -dewatearing of the mixture of substances to be treated, so that following compacting a dry-stable body is present wh1ch cannot be eluted any further. This body may, for example, be stored as a substitute fuel being an alternative for fossile energy carriers, or in a garbage dump. The main appl1cation of the process according to the invention presumably resides in the treatment of waste matter; in principle the process may, however, also be applied for any other mixture of substances including organ1c constituents. As a washing agent, water is customarily used wh1ch is recycled in the process of the invention. The air for hydrolysis and thermophil1c drying of the mixture of substances may be guided in counterflow to the mixture of substances but also in parallel flow. Further advantageous developments of the invention are the subject matters of the further subclaims. In the following, preferred embodiments of the invention are explained in more detail by way of schemat1c drawings, wherein: Fig. 1 is a sectional view of a reactor in wh1ch hydrolysis of a mixture of substances containing organ1c constituents takes place; Fig. 2 shows a reactor for performing aerob1c, thermophil1c drying; Fig. 3 shows an installation having a plurality of hydrolysis and drying reactors in accordance with Figs 1 and 2 arranged in sequence; j Fig. 4 shows a dev1ce having a plurality of reactors for hydrolysis and/or drying arranged in sequence in a common container; Fig. 5 is a top view of the dev1ce of Fig. 4; and Figs. 6 and 7 show alternative embodiments of a reactor. Fig. 1 shows a process diagram explaining the process of the invention and the dev1ce for carrying out the process. Accordingly, the aerob1c hydrolysis (aerob1c biogen1c reaction and percolation) takes place in a reactor 1 to wh1ch the mixture of substances 2 to be processed is supplied through a material feeding means 4. The mixture of substances to be processed contains a large proportion of structured material and organ1c matter. The like mixtures of substances occur, for example, in household waste, biolog1cal waste, industrial waste etc.. The reactor 1 is designed as a closed container, so •that the material flows descr1bed in more detail hereinbelow are supplied via lock means, valve means etc. . The reactor 1 proper preferably is a steel or concrete container that is supplied from above with the mixture o.f substances (residual waste) in the shown embodiment. A substantial proportion of the organ1c fraction of the mixture of substances consists of short-chained compounds that, are mostly absorbed on a surface. If this surface is surrounded by a flow of warm water, primarily non-soluble compounds are also,hydrolyzed and washed out. The hydrolysis degree depends on the dwelling time in the reactor 1. The smell-intensive components of the mixture of substances and the hydrolysis products are well water-soluble and may be washed out. By percolation one therefore achieves a reduction of the organ1c matter and a deodorization of the mixture of substances. Together with the leaching fluid (process water), fine sand part1cles are furthermore carried off. The reactor 1 is closed so as to be'smell tight, and the exhaust air is deodorized in the manner descr1bed more closely hereinbelow. During percolation, process air is additionally supplied, whereby the phys1co-chem1cal effect of water extraction is enhanced by intensifying the bacterial decomposition. In the aerob1c environment, the m1croorganisms begin to.excrete exoenzymes wh1ch split part1cle-shaped polymer components into monomers and solubilize them. During percolation, approx. 10% of the inert substances (glass, ceram1c, sand) are l1berated wh1ch are discharged together with the leaching fluid. Separation takes place inside a sand sifter wh1ch at the same time allows for supplementary rinsing for sand washing. In the embodiment in accordance with Fig. 1, the charging means 4 is positioned at the upper end section of the- reactor 1 when viewed in the direction of gravity. In the lower range of the reactor 1 at least one discharge means 6 is formed through wh1ch the processed and biolog1cally decomposed mixture of substances may be withdrawn from the reactor 1. The-reactor 1-'moreover comprises below the discharge means 6 (representation of Fig. 1) a collector 10 wh1ch is separated from a reaction chamber 12 by a sieve floor 8. The discharge means 6, wh1ch shall be descr1bed in more detail hereinbelow, is designed such that the mixture of substances resting on the sieve floor 8 is discharged from the reactor in a layered configuration, and the openings of the sieve floor 8 are kept unobstructed.. The collector 10 commun1cates with an air connection duct 14 and a leaching fluid exit 16. In the head area of the reactor 1 another air connection duct 18 and a leaching agent distr1butor 20 are arranged. The leaching fluid (water) used for percolation or extraction of the organ1c constituents of the mixture of substances is fed into the reactor through the distr1butor 20 and withdrawn through the exit 16. For the purpose of a simplified flow management, the floor 22 of the reactor 1 is inclined towards the exit 16, so that the leaching fluid gathers in the range of the exit 16. The lower air connection duct 14 in the representation of Fig. 1 is connected with air conveying means 24. Depending on the design of the air conveying means (fan, compressor) , a flow 25 from the lower air connection duct 14 to the upper air connection duct 18 or a flow 27 in a reverse direction from the upper air connection duct 18 to the lower air connection duct 14 may be adjusted inside the reactor 1. I.e., -depending on the design of the air conveying means 24, air flows through the mixture' of substances received in the reactor 1 from bottom to top or from top to bottom in the representation according to Fig. 1. The flow of leaching fluid takes place in the direction of gravity, namely, from the distr1butor 20 disposed in an upper location in the reactor 1 towards the exit 16. The leaching fluid exiting from the reactor 1 is treated by means of a sewage treatment' dev1ce 26 (anaerob1c filter) descr1bed in more detail in the following, and then recirculated to the distr1butor 20. The residue resting on the sieve floor 8 is withdrawn as discharge material 2B through the discharge means 6 and either supplied to further processing as a product 30 or, in turn, recycled to the charging means 4 als circulation material 32. The separation of the discharge material 28 into product 30 and/or circulation material 32 takes place through a suitable apportioning means 34 wh1ch may, for example, have the form of a slide gate, trap, distr1buting guide etc.. I.e., by means of suitable adjustment of the apportioning means 34 a part of the discharge material 28 may be recirculated into the reactor 1 als circulation material 32 and may there be utilized for inoculation of the mixture of substances and thus for accelerating the biolog1cal decomposition. By circulating all or part of the mixture of substances with the aid of the conveying means, shear forces are moreover introduced into the circulation material, so that surfaces of the mixture of substances are reformed and part1cles are separated into f1bers. For a better understanding, the above descr1bed single components of the dev1ce according to the invention shall now be explained in more detail. The incoming mixture of substances 2 has in advance been treated mechan1cally in a known manner so as to have a predetermined maximum part1cle size. This processed mixture of substances 2 is supplied via suitable conveying means, for example conveyor belts 36, to the charging means 4 whereby a distr1bution of the mixture of substances 2 across the reactor cross-section takes place. In the shown embodiment the charging means 4 includes a transversal conveyor 8 whereby the mixture of substances is distr1buted in the plane of drawing and in a transversal direction relative to the plane of drawing, and supplied to the reactor 1 by material hoppers 40 wh1ch are distr1buted over the cross-section. By actuating the material hoppers 40 or the transversal conveyor 38, the mixture of substances 2 is introduced into the reactor 1 in layers, so that pract1cally n-layers 4.2 are arranged on the sieve floor 8 on top of each other. The filling height H of the reactor 1 is selected such that the distr1butor 20 for the leaching fluid is located above the bulk material. The distr1butor 20 may, for example, present a multipl1city of spraying heads 44 distr1buted across the reactor cross-section, whereby the leaching fluid may be distr1buted homogeneously over the topmost layer 42. In che embodiment represented in Fig. 1, the discharge means 6 has the form of a horizontal conveyor designed such that the respective bottom layer of the mixture of substances resting on the sieve floor 8 may be discharged in a horizontal direction. In the represented reactor 1 the discharge means 6 has the form of a sliding or scraper floor as descr1bed, for example, in WO 95/20554 Al. The -like sliding floors are, for example, employed in sewage sludge silos, composting installations etc. and are known from the prior art, so that only the essential components shall be descr1bed hereinbelow. In accordance with Fig. 1, the sliding floor includes a plurality of conveyor wedges 46 spaced apart in a horizontal direction (view of Fig. 1) and arranged on a thrust rod 48. The-thrust rod 48 may be moved reciprocally, in parallel with arrows 52, 54 in Fig. 1 with the aid of a hydraul1c cylinder 50 or some other drive means. The front surfaces of the conveyor wedges 46 facing the discharge opening have the form of vert1cal surfaces 56, whereas the rear surfaces are inclined surfaces 58. Through corresponding control of the hydraul1c cylinder 50 the thrust rod 48 is period1cally moved back and forth, wherein during the movement of the thrust rod 48 in the direction or. arrow 52 (to the left in Fig. 1) the mixture of substances of the lowest layer slides upwards along the inclined surface 58 and comes to lie in the space behind the respective conveyor wedge 46. During the subsequent return movement of the thrust rod 48 in the direction of arrow 54, this material is carried along by the vert1cal surface 56 and conveyed to the right to the neighboring conveyor wedge 46 or to the discharge opening. I.e., the height of the conveyor wedges 46 determines the height of the layers of the discharged mixture of substances. In order to maintain the extracting conditions in the reactor 1 constant, the layer th1ckness of the discharge material about corresponds to the layer th1ckness of the material supply, with the filling height H accordingly remaining essentially constant. As was already mentioned at the outset, a part of the discharge material 28 may be recycled to the conveyor means 36 or directly to the charging means 4 as inoculation material (circulation material 32) . In principle it is also poss1ble to use all of the discharge material 28 als circulation material 32, in wh1ch case the mixture of substances passes through the reactor I several times and is 'only discharged as product 30 following, for example, 4 runs. The sieve floor 8 arranged underneath the discharge means 6 has a mesh size Z selected as a function of the composition and part1cle size of the mixture of substances to be processed. The construction of the thrust rod 48 and of the conveyor wedges 46 is selected such that the sieve floor 8 is cleaned by the reciprocating movement of the scraper floor, so that an obstruction of the meshes may be prevented. Layered discharge of material results in a movement of layers of the nuxture of substances from top to bottom through the reactor 1 in a vert1cal direction (Fig. 1) . As was already mentioned above, the air conveying means 24 may have the form of a fan or compressor, so that different directions of air flow may be adjusted in the reactor 1. In either case the entry and exit ranges of the reactor 1 are selected such that the air flows through the layered mixture of substances while being distr1buted over the entire reactor cross-section. This air flow is ind1cated by dashed lines in the representation of Fig. 1. The leaching fluid flows through the layered mixture of substances along the solid-line arrows from top to bottom and enters, laden with organ1c matter, into the collector 10 through the sieve floor 8. The laden leaching fluid 60 is withdrawn via the exit 16 and supplied to the sewage treatment dev1ce 26. The latter comprises a foreigr, matter separator 62 in wh1ch foreign matter 64 such as, for'example, sand, pebbles, suspended matter, float matter etc.. are separated out. Such foreign matter separators may, for example, comprise a settling tank and a skimmer for separating out the mentioned foreign matter 64.. The leaching fluid freed from the foreign matter and containing colloidal organ1c compounds in aqueous phase is then supplied to an anaerob1c fermeter 66, for example a biogas or digestion tower installation. Metabol1c end products produced in this anaerob1c waste water treatment are methane and carbon dioxide and in some cases small amounts of hydrogen sulfide. This biogas obtained as a decomposition product may be converted into electr1city and heat in suitable block-type thermal power stations. A part of the energy recovered from the biogas is returned into the process of the invention wh1ch is thus largely self-suff1cient as:regards energy. Preliminary trials showed that in the treatment of one [metr1c] ton of supplied household waste, approx. 80 Nm* of biogas having an energy content of 6.5 kWh may be obtained. In the above descr1bed embodiment a sewage water purif1cation plant is associated with the reactor. As an alternative, the leaching fluid might also be incorporated into .an existing sewage purif1cation plant, or be introduced directly into the sewers, or supplied to another treatment step. For the supply, fresh water or industrial process water or weakly loaded sewage water will be used in that case. The anaerob1c fermenter 66 is followed immediately by a two-stage aerob1c aftertreatment 70, wherein digestion process water from the biogas installation is subjected . to an aftertreatment for minimizing the residual load, and nitrogen is eliminated. Depending on load and legal regulations in force, the loaded sewage 72 thereby produced is supplied to a further treatment stage or directly introduced into the sewer system. The leaching fluid purified in the aerob1c biolog1cal stage 70 is then supplied to the reactor 1 by way. of the distr1butor 20. As is .ind1cated in Fig. 1, a partial flow of the digestion process water may be supplied directly from the anaerob1c fermenter 66 to the distr1butor while bypassing the 2-stage aerob1c biolog1cal stage 70, in order to exert a catalyt1c influence on biolog1cal decomposition in the reactor 1. As a result of the flow management according to the invention inside the reactor 1, aerob1c hydrolysis takes place, with an aerob1c, thermophil1c heating occurring as a result of the air flowing through the mixture of substances 2 and the humidity of the mixture of substances wh1ch is adjusted by way of the leaching fluid, whereby the 'cells of the organ1c matter are split open and the l1berated organ1c substances are discharged by the leaching fluid. Decomposition of the organ1c materials is due, on the one hand, to the aerob1c decomposition of the available carbon C into CC>2 (carbon1c acid) and on the other hand to leaching, out of the dissolved and acidified organ1c matter and removal by way of the leaching fluid. Due to the aerob1c, thermophil1c reaction and the simultaneous decomposition of the organ1c compounds, the temperature in the mixture of' substances rises (to approx. 40 to 50°C, for example) during the extracting step. As a result of this temperature increase water vapor is l1berated, wh1ch is discharged via the supplied air. This water vapor discharged together with the air may be supplied to the above descr1bed sewage water purif1cation as a condensate. The air flowing off from the reactor 1 is laden with carbon dioxide as a decomposition product and with the water yapor produced by the heating. The exhaust air laden with organ1c components may be supplied to a biofilter wherein biolog1cal cleaning by means of aerob1c m1cro-organisms takes place. As a leaching fluid initially pure water is used, wh1ch is made acid1c by salts dissolved during the aerob1c treatment following the startup of the installation and obtention of nearly stationary process parameters. The slight acidif1cation of the water enhances leaching of soluble organ1c, inorgan1c substances and water-soluble fatty acids. As is moreover represented in Fig. 1, the mixture of substances 2 located inside the reactor 1 is subjected to intermittent pulses due to the reciprocating movement of the conveyor wedges 46, whereby shear, transversal and longitudinal forces are introduced into the mixture of substances and poss1bly formed flow channels of the leaching fluid and of, the air are destroyed. The magnitude of these forces is designed such as to be capable of destroying these channels and chimneys on the one hand, however not to result in destruction of the layered structure. In the embodiment represented in Pig. 1 these pulses are brought about-'by the movement of the scraper floor; as an alternative, however, as is represented in Figs. 6 and 7, additional means for inducing shear .forces in the mixture of substances 2 and for destroying the channels might be employed, as represented in Figs. 6 and 7. Following the above descr1bed hydrolysis, i.e. following decomposition of the organ1c constituents and extraction of these constituents by means of the leaching fluid, the discharge material 28 is supplied to a drying step. It was found to be. part1cularly advantageous if this drying takes place as aerob1c drying, for the residual humidity may then be reduced at minimum ene'rgy expense. The like aerob1c drying may be effected, for example, by interrupting the supply of leaching fluid through the distr1butor 20, so that nothing but air flows through the mixture of substances 2 following hydrolysis. As a result of flow through the humid mixture of substances 2, further aerob1c decomposition of the as yet available carbon C into carbon dioxide takes place. Moreover, similarly to hydrolysis, the mixture of substances is heated due to the m1crobial conversion and thereby water vapor is discharged by way of the flow of air passing through. Due to the aerob1c decomposition of the carbon and discharge of the water vapor, the residual humidity of the mixture of substances is reduced, with the desired proportion of dry substrate being adjustable in a simple manner through the duration of aerob1c drying. In the above descr1bed embodiment, hydrolysis and aerob1c drying are thus performed in a single reactor 1. I.e., the reactor 1 may be used both for drying and percolation without any modif1cation, so that a simple structure of the installation is ensured. As an alternative, it would be poss1ble to arrange downstream from the reactor 1 of Fig. 1 a dryer in accordance with Fig. 2 to wh1ch the discharge material 28 from the reactor 1 is supplied. This aerob1c dryer 74 essentially has the same construction as the reactor 1 of Fig. -1, i.e. the mixture of 'substances, in this case the discharge material 28, is introduced via a charging means 4 into a container.provided with lock means, and following completed aerob1c drying is discharged via a discharge means 6. Other than the above descr1bed reactor 1, the dryer 74 has a plurality of air connection ducts 14 arranged above each other perpend1cularly to the plane of drawing, so that the air may be injected in sheet form. The drying air, in turn, may be guided in counterflow or in parallel flow with the flow of the mixture of substances and is accordingly supplied and discharged through air connection ducts 14, 16. Other than the reactor of Fig. 1, the dryer 74 of Fig. 2 does not include a distr1butor 20 for the appl1cation of leaching fluid. In the aerob1c dryer 74, in turn, partial recirculation of the dry material. 76 present at the exit from the dryer 74 as circulation material 78 and/or discharge of a dried product 80 is provided for. The mixture of substances to be dried passes through the dryer 74, once again preferably in a layered form, with channel formation being suppressed by shear, transversal and longitudinal fcrces applied in the form of pulses. This 2-stage process might, of course, be carried out by means of two reactors arranged in sequence in accordance with Fig.. 1, with hydrolysis in the first reactor taking place through supplying air and leaching fluid, whereas in the second, downstream reactor 1 only aerob1c drying as a result of supplying air takes place. Fig. 3 shows an embodiment wherein three reactors la, 1b, 1c in accordance with Fig. 1 are combined with three dryers 74a, 74b, 74c in accordance with Fig. 2. Accordingly, a common conveyor means 36 is associated to the three reactors la, 1b, l"c, whereby the mixture of substances 2 may be supplied to'the single reactors la, 1b, 1c. By means of suitable apportioning means 34, in turn, the flow of material to the single reactors la, 1b, 1c may be adjusted. .The discharge material 28a, 28b, 28c from the single reactors la, 1b, 1c may in turn be recirculated by way of the apportioning means 34 als circulation material 34 or, in turn, supplied as product 30 to further processing, or as discharge material 28 to the aerob1c drying. Herein the discharge material 28 from reactors la, 1b, 1c is supplied to the dryers 74a, 74b, 74c through conveyor means 84 and suitable apportioning means 34. In the schemat1c representation of the installation in accordance with Fig. 3 it is furthermore provided that the mixture of substances 2 is also supplied to drying directly, i.e. while bypassing the reactors 1. This is the case, for example, when the mixture of substances present already includes a considerable proportion of dry substance, so that no more wet washing takes place. The discharge material from the dryers 74, i.e. the dry material 76a, 76b, 76c is then either further processed as dry-product 86, again supplied to drying as circulation material 78, or supplied to means 90 for dewatering and/or compacting as an -intermediate product 88. The means 90 is also used for further processing of the discharge material from the reactors/dryers represented in Figs. I, 2. The means 90 may, for example, have the form of an extruder or a dryer/extruder press so that as a result of the mechan1cal action and the heat generated by the pressure buildup, further dewatering or drying of the intermediate product 88 takes place. Inside the means 90 the extracted residual waste is adjusted to a dry-substance content of > 60%. In a preferred embodiment the means 90 moreover contains a high-performance press whereby the extracted, dewatered material may be pelleted. Herein densities of 1.7 t/m3 are attained. The energy expense for producing the pellets amounts to -approx. 1% of the energy content of the pellets when one assumes a mean energy content of 14 MJ/kg. Depending on the design of the means 90, the dewatered final product 52 may be present as a pellet, briquet or in another compacted form. By the above descr1bed process steps a product may be produced wh1ch cannot be eluted further, has no breathing activity, and is characterized by a large proportion of dry substance, wherein it is not necessary to employ thermal energy from the outside for drying in contrast with the known process. The material dewatered with the aid of the means 90 may be subjected to subsequent drying by means of composting or belt drying. Conventionally post-rotting was previously connected after a mechan1cal-biolog1cal treatment of waste in order to attain additional decomposition of organ1c material and drying of the leached residue. Post-rotting may readily take place in an exposed pit. The proportion of biogen1c material is suff1ciently high even after percolation, so that the rotting temperature will rise to 70°C within 4 to 6 days. Within 10 to 16 days the residue thus treated attains a dry substance content of up to 80%. As waste heat for drying of the percolation residue would be available in the above descr1bed process owing to biogas extraction and conversion into electr1city in a gas engine, a space- saving drying process may also be employed for post-rotting. The arrangement represented in Fig. 3 is selected when a continuous operation is desired. At high throughputs, the installation may be expanded by adding further modules (reactors 1, dryers 74). The conveying means 36 and 84 and the apportioning means 34 (material.deflection) may be controlled such that the order of Charging, emptying or mixing (circulation material) of the single reactors, dryers may be changed in any desired order. Fig. 4 shows an embodiment wherein a container 96 is separated into three chambers or reactors la, 1b, 1c by two partition walls. These chambers correspond to the means in accordance with Fig. l and in accordance with Fig. 2 wherein the hydrolysis and/or the aerob1c drying may be carried out. To the tight container 96 a common conveyor means 36 is associated whereby the mixture of substances 2 to be processed is supplied to the container 96. By the common conveyor means 36 the mixture of substances is guided via the apportioning means 34 to a transversal conveyor 38 having the form of a distr1butor crane in the shown embodiment. The latter includes a material chute 40 wh1ch is movable across the entire cross-sectional area of the container 96 by means of the distr1butor crane (transversal conveyor 38). Hereby it is ensured that the partial spaces la, 1b, 1c of the container 96 may be charged with the layered mixture of substances 2. Discharging the treated mixture of substances (discharge material 28 or dry material 76) takes place hrough a discharge means 6 wh1ch may, for example, be designed like the one in Fig. 1. In accordance with the variant-s represented in Fig. 4, it is also poss1ble to form a plurality of discharge means 6a, 6b, 6c in laterally adjacent arrangement in the range of the floor of the container 96. In the shown embodiment the container 96 has the form of a multiple-chamber dryer designed to have air connection ducts 14, 18, with only the air connection duct 18 arranged on top being shown in Fig. 4. In this variant, as well, it is provided that the air is guided to the mixture of substances in parallel flow or in counterflow. The container 96 might, of course, also be designed as a reactor having a plurality of partial chambers. The reactors/dryers represented in Figs. 1 to 3 may, of course, also be designed to include a plurality of laterally adjacent discharge means 6. . The discharge material 28 may be returned to the conveyor means 36 via the apportioning means 34 as circulation material 32, or, however, be discharged as product 30. Fig. 5 shows a top view of the container 36 of Fig. 4 explaining distr1bution of the mixture of substances 2. Accordingly, the mixture of substances 2 is charged on the conveyor means 36, for example a conveyor belt, and thereby supplied to a distr1butor crane 38 that is movable in the direction of arrows 100, 101 above the partition walls 98, 99. The distr1butor crane 38 carries one movable or a plurality of stationary material chutes 40, so that the entire width (vert1cal Fig. 5) of the partial chambers la, lb, 1c may be covered. The processed mixture of substances is discharged from the container 96 in the direction of arrow 102, and this discharge material 28 is carried off through suitable conveyor means either as product 30 or as circulation material 32. The latter is transported back to the conveyor means 36 by a conveyor belt and then once more charged into one of partial spaces la, 1b, 1c. In the above descr1bed embodiments, formation of chimneys was prevented by the forces introduced into'the bulk material through the discharge means 6, wh1ch caused a wave-type vert1cal displacement in the heap material and thus resulted in reformation of the heap material surfaces and destruction of channels. Depending on the quality of the mixture of substances to be processed, the shear forces thus introduced may, however, sometimes be too weak for bringing about the required mechan1cal decomposition of the bulk material. In the above descr1bed reactors 1 the proportion of the circulation material 32 is then increased, so that the shear forces required for material decomposition are then introduced by way of the conveyor elements for conveying the circulation materis.! 32. With respect to energy and material expenditure, this variant is still substantially more favorable than the prior art descr1bed at the outset, wherein agitators are used inside the reactor in order to introduce the shear forces. The expenditure in terms of energy and apparatus technology may be further reduced if the reactor/dryer according to the -invention is -designed in the manner descr1bed in Figs. 6 or 7. In the embodiments descr1bed in Figs. 1 and 2, the process air was injected into the bottom portion of the reactor 1 or dryer, respectively, through one or a plurality of air connection 'ducts 14 and then enters through the sieve floor 8 into the heap material (bulk material). In contrast, in the embodiments represented in Figs. 6 and 7, the process air is injected through a multipl1city of lances 110 distr1buted over the cross-section of the reactor 1, the nozzles 112 of wh1ch open into the lower range (view of Figs. 6, 7)of the bulk material 114. The lances 110 extend through the sieve floor 8 and the discharge means 6 - in the present case the sliding floor. The lances 110 for process air or pressurized air are each connected through a control valve 116 to a pressure line 118 wh1ch opens into a pressure accumulator 120. The latter is connected to a compressor 122 through wh1ch fresh air or air 124 recycled from the exhaust air treatment (biofilter) may be taken to the system pressure, i.e. the pressure in the pressure accumulator 120. The control valves 116 are connected to a process control means 126 and may thus individually be controlled open and closed, respectively. The opening cress-section of the control valves 116 may be continuously variable depending on the process control means 126, so that the pressure of the process/pressure gas is variable: The system pressure in the pressure accumulator 120 is preferably adjusted to a pressure of more than 4 bar. Upon complete opening of a control valve 116 of a lance 110, pressurized -air 128 exits from the nozzle opening in an upwardly direction (view of Figs. 6, 7) and flows through the bulk material 114 in a vert1cal direction at the maximum pressure, with the arrows in Figs. 6, 7 ind1cating that the pressurized air 128 is also deflected in the transversal direction. The bulk material 114 is partially whirled uo or flui'dized in the range through wh1ch the pressurized air 128 flows, so that the surfaces of the heap material are reformed and channels are destroyed. I.e., by the injected pressurized air a partial undulating movement 130 is generated in the bulk • material 114, wh1ch moves away from the nozzle 112 of the respective lance 110 through the bulk material 114 in an upwardly direction. Due to this undulating movement, a relative movement of the mixture of substances is induced, so that the surfaces of the part1cles are torn open and thus the mass transfer area is increased. As the pressurized air is only injected in pulses, the bulk material 114 again collapses after the control valves 116 are closed, so thac again shear forces are introduced into the bulk material 114 wh1ch result in repeated reformation of the surfaces and in destruction of channels. The laden air 123 exiting from the reactor 1 is supplied to a biofilter. Owing to the injected pressurized air, bas1cally two effects are attained. For one thing shear forces are introduced in the above descr1bed manner into the bulk material 114, on the other hand the process air required for hydrolysis and/or drying is also supplied, so that the introduction of shear forces and feeding of process air are pract1cally combined. Model calculations have shown that on account of the pressurized air connection duct according to the invention, the energy requirement may be reduced by up to in excess of 50% in comparison with a conventional reactor including an agitator. The process control 126 and the control valves 116 are designed such that the px-essure of the process/pressurized air may be varied over time, so that for example over a predetermined time interval process air only having a low pressure (0.5 bar) is supplied wh1ch is required for drying or hydrolysis, however does not result in considerable introduction of shear forces into the bulk material 114. Depending on the bulk height and the quality of the mixture of substances to be processed, pressurized air is then intermittingly supplied at a comparatively high pressure (> 4 bar) in order to introduce the above descr1bed shear forces and avoid'a formation of channels. The valves 116 of the multipl1city of pressure lances 110 of the reactor 1 may also be controlled consecutively, so that an "expansion wave" propagating in i parallel with the plane of drawing or perpend1cularly to the plane of drawing in the representation according to Pigs. 6 and 7 passes through the bulk material. For the rest, the embodiment represented in Fig. 6 corresponds to the above descr1bed embodiments. I.e., the mixture of substances 2 is introduced into the reactor 1 by way of the charging means 4 from above in a layered configuration and migrates through the latter, with the layered structure remaining substantially unchanged due to the supply of pressurized air and the resulting partial fluidization of the bulk material. The processed mixture of substances is then discharged via the discharge means 6, i.e. a. sliding floor, and supplied to the further treatment steps. In the embodiment represented in Fig. 7, the mixture of substances 2 is supplied at the left-hand front face of the reactor 1 in the representation of Fig. 7 and is at the opposite side of the reactor 1 discharged in a downwardly direction. Accordingly, the mixture of substances migrates through the reaction chamber 12 having a vert1cally arranged layered structure as is designated by reference symbols 1 to ln. I.e., the mixture of substances moves through the reactor in a horizontal direction (1) while being displaced through . the reactor in a vert1cal direction in the embodiment represented in Fig. 6. For the rest, che embodiments represented in Figs. 6 and 7 correspond to the above descr1bed embodiments, so that reference is made to the above explanations with regard to the remaining components. For the sake of simpl1city, the same reference numerals were used in Figs. 6 and 7 for corresponding components as in Figs. 1 to 5. In simple words, in the embodiments represented in Figs. 6 and 7 the agitator used in the prior art was replaced with a "pressurized air agitator", with the pressure for the pressurized air being selected such that the layered structure is essentially preserved. Thanks to the poss1bility of individually controlling the control valves 116 that are distr1buted over the cross-section of the reactor 1, the bulk material 114 may purposely be subjected to pressure pulses, so that the introduction of shear forces may be applied depending on the process, i.e., appl1cation of pressurized air bzw. process air may be effected as a function of the quality of the mixture of substances to be processed and of the dwell time in the reactor 1. The appl1cant reserves the right of directing independent sets of claims to the variants i represented in Figs. 6 and 7 and 1 to 5. A process for-'treating a mixture of substances containing structured constituents and organ1c matter, and a dev1ce for carrying out this process are disclosed. In accordance with the invention, the mixture of substances is subjected to pulse-type or-period1cal appl1cation of force, so that the formation of flow channels for a leaching fluid or process air in a bulk material may be prevented. We Claim: 1. a process for treating a mixture of substances (2) containing structured constituents and organic matter which is received in the form of bulk material and subjected to aerobic decomposition or aerobic drying in a reactor (1) by means of a flow of process air therethrough and/or addition of a leaching fluid so that the soluble organic constituents are discharged, characterised in that said mixtures of substances (2) is subjected to pulse-type or periodical application of pressurised air having a pressure of more than 2 bar and directed approximately perpendicular to and/or in parallel with the direction of displacement of said mixture of substances so as to introduce shear forces and prevent channel formation. 2. A process as claimed in claim 1, wherein the compressed air or the heated air is directed through jets (112) in the upper part and/or lower part of the reactor (1). 3. A process as claimed in claim 2, wherein the heated air and the compressed air are directed through the same jets (112). 4. A process as claimed in any one of the preceding claims, wherein the reactor (1) remains in continuous operation and the mixture is taken through the reactor (1) approximately parallel or at right angles to the heated air. 5. A process as claimed in any one of the preceding claims, wherein the flushing-out liquid enters the reactor (1) through a distributor (44) in the top part of the reactor (1). 6. A process as claimed in any one of the preceding claims, wherein the compressed air is applied at a pressure of greater than 2 bar and preferable greater than 4 bar. 7. A process as claimed in any one of the preceding claims, wherein the treated mixture (2) is removed via an opening (6) fixed into the lower part of the reactor (1), through which all or some of the force can be applied to the waste heap. 8. A process as claimed in any one of the preceding claims, wherein the air- induced breaking down is supplemented by air-drying of the mixture. 9. A process as claimed in claim 3, wherein the mixture goes through a series of breaking-down and drying procedures one after the other. 10. A process as claimed in any one of the preceding claims, wherein compression of the mixture is added to its breaking-down and/or air-drying. 11. A device, in particular for implementing the process as claimed in any of the preceding claims, comprising a reactor (1, 74, 96) having associated a charging means (4) for introduction of a mixture of substances, wherein inlets (14, 18) for introducing process air are arranged in the bottom portion and/or in the head portion of said reactor (1, 74, 96), and/or a distributor (20) for leaching fluid is arranged in the head portion of the said reactor (1, 74, 96) characterised by a pressurised air system (6, 112) whereby pressurised air of more than 2 bar may be supplied in the form of pulses or periodically for decomposition of said bulk material (114), and by discharge means (6) in the bottom portion of said reactor (1, 74, 96). 12. A device as claimed in claim 11, wherein the air-compression equipment has jets (112) leading into the lower part of the reactor (1) that are connected to a pressure chamber (120) of an air compressor (122). 13. A device as claimed in claim 11 or claim 12, wherein a control mechanism is connected to the air-compression equipment whereby the pressure of the compressed air or the heated air can be varied. 14. A device as claimed in any one of claims 11 to 13, wherein compressed air and heated air can be applied together through the air-compression equipment. 15. A device as claimed in any one of claims 11 to 14, said device being provided with gas cleaning equipment for cleaning and bringing back the heated and/ or compressed air. 16. A device as claimed in any one of claims 11 to 15, wherein equipment is installed in the lower part of the reactor (1, 74, 96) whereby turbulence is at least partially created. 17. A device as claimed in any one of claims 11 to 16, wherein several reactors (1, 74, 96) are connected in series, so that a system of conduits (4) common to several reactors (1, 74, 96) is installed, into which the mixture (2) to be treated can be fed. 18. A device as claimed in any one of claims 11 to 17, said device being provided with compacting equipment (90) for compressing, removing water and shaping the treated mixture.

Full Text

The invention relates to a process for treating a mixture of substances containing structured constituents and organ1c matter, in accordance with the preamble of claim 1, and a dev1ce in part1cular for carrying out this process.
Such a process is, for example, utilized for treating residual waste matter. In DE 196 48 731 Al a waste matter treatment method is descr1bed, wherein the residual waste matter is treated in a percolator. By such a percolation or extraction, organ1c constituents, inorgan1c substances and in a given case water-soluble fatty acids are leached from the waste matter by an extracting or washing agent. The residue is withdrawn from the percolator and, following a subsequent drying, supplied to combustion or dumped,.
It was found that by this process the organ1c substances cannot be removed in the required extent from the residual 'waste matter.
The drawbacks of this known waste matter treatment process may be eliminated by the process for treating biolog1cal waste as disclosed in WO 97/27158 Al. In this process a novel percolator is employed wherein the waste matter passes through the reactor in a horizontal direction (longitudinal direction), and a biogen1c reaction is superseded to the percolation process by supplying atmospher1c oxygen (process air).
As a result of supplying process air, the cells of the organ1c matter are split open and the l1berated organ1c substances are carried off by the leaching fluid. In order to avoid channel formation within the waste matter and introduce shear forces, an. agitator or circulating apparatus is provided in the reactor, whereby the waste matter is mixed thoroughly in a vert1cal direction (in parallel with the direction of flow of leaching fluid and process air) and also displaced in the direction of transport.
It is a drawback in this process that for guiding and mixing the waste matter within the reactor, a considerable expense must be incurred wh1ch substantially influences the investment costs. Such a complex mechan1cal structure also harbors the risk of failure of the installation owing to a malfunction in the transport system of the reactor, so that a comparatively high expense for serv1cing the reactor must be incurred. Such downtimes of the reactor as a result of the necessary maintenance or of a malfunction in the reactor periphery may, however, only be neutralized by providing corresponding buffer spaces wherein intermediate storage of the waste matter during the downtime of the reactor is poss1ble. In DE 196 08 586 Al a rotting process is descr1bed wherein the exposed pit is subjected to pressurized air.
In contrast, die invention is based on the object of furnishing a process for treating a mixture of substances containing structured constituents and organ1c matter, and a dev1ce wherein suff1cient decomposition of the organ1c proportion takes place at minimum expense in terms of dev1ce technology.
This object is achieved by the features of claim 1 as far as the process is concerned, and by the features of claim 12 as far as the dev1ce is concerned.
Through the measures of causing the mixture of substances (for example residual waste matter) containing structured constituents and organ1c matter to pass through the reactor in the absence of any substantial longitudinal and transversal mixing, and of preventing channel formation by applying forces to the mixture of substances wh1ch are directed approximately in parallel with or transversally to the direction of displacement, the reactor may have a substantially more simple construction than in the above descr1bed prior art because it is not necessary to provide an agitator for lateral mixing. The forces are preferably introduced from the peripheral area of the reactor, for example through a suitably designed discharge means or by means of injected gas, preferably pressurized air. In part1cular when pressurized air is used, shear forces are also applied to the bulk material, whereby the surface of the heap material is reorganized and part1cles of the mixture of substances are separated into f1bers.
The reactor may be employed as a percolator and dryer without any restructuring or modif1cations becoming necessary.
:
Upon introduction of the forces preventing channel formation by way of the discharge means, the mixture of substances is preferably circulated at least in part, so that shear forces are introduced due to the conveyor elements bringing about the circulation.
The flow management according to the invention makes it poss1ble to design the reactor with a high degree of compactness, wherein it is poss1ble to position all of the feeding and discharging means at the head or bottom portion of the reactor.
In a part1cularly preferred embodiment, the forces for prevention of channel formation and the shear forces required for surface reformation and for tearing open the part1cles are applied through a pressure gas, preferably pressurized air, wh1ch is injected into the bulk material (heap material) from the peripheral area of the reactor. By the pressurized air the heap material is partially expandedy so that a surface reformation takes place in the bulk material and'the part1cles are torn open as a result of the introduced shear forces - the mass transfer area for decomposition of the mixture of substances by means of the atmospher1c oxygen and of the leaching fluid is increased.
In a part1cularly preferred embodiment, the pressurized air and the process air are supplied through nozzles arranged in the foot portion and/or in the bottom portion of the reactor.
In accordance with the invention it is preferred if . the-mixture of substances passes through the reactor essentially vert1cally (in parallel with the direction of gravity) or horizontally, so that the mixture of substances is guided approximately in parallel or in a flow transversal to the process air.
In a case where the reactbr is employed as a percolator, the leaching fluid is preferably supplied through a distr1butor in the head portion of the reactor.
The pressurized air is supplied at a pressure of more than 2 bar, preferably more than 4 bar, whereas a pressure of 0.5 bar is customarily applied to the process air.
The nozzles for introduction of the process air and/or pressurized.air may advantageously be controlled individually, so that a specif1c pressurized air profile may be adjusted across the reactor cross-section.
' The use of pressurized air for introducing shear forces and for preventing channel formation has the advantage of the atmospher1c oxygen required in the bulk material for the aerob1c process being supplied concurrently, so that the pressurized air bas1cally fulfills a twofold function:
1. supplying atmospher1c oxygen for aerob1c
decomposition, and
2. introduction of shear forces.
In a more simple embodiment the forces for preventing channel format ion. in the bulk material are, for example, supplied through a discharge means arranged at the bottom portion of the reactor. This discharge means may, for example, be a scraper floor installation or a similar conveyor means for discharging the mixture of substances by layers. This variant has the additional advantage of feeding and discharging openings in the bottom portion of the reactor being kept free owing to the advance movement of the discharge means, so that the leaching fluid may exit and pressurized air or process air, respectively, may penetrate into the bulk material. As a discharge means, a worm conveyor carpet, a walking floor, silo filler means etc. may also be used. These discharge means may, of course, a'lso be used' in the above descr1bed embodiment with pressurized air.
Inasmuch as the mixture of substances passes through the reactor preferably in the form of layers, the dwell time of the mixture of substances inside the reactor may be determined with high precision in the case of
continuous process management, so that the passage times with respect to the biolog1cal decomposition may be optimized. In the solutions named at the outset, only a mean dwell time value could be determined due to the longitudinal and transversal mixing by means of the agitator.
The laden process air or the laden pressurized air, respectively, are supplied to a waste gas purif1cation wherein organ1c constituents are separated and the purified air is recycled into the process.
The energy balance of the installation may be further improved if the laden leaching agent is supplied to a sewage water purif1cation. The latter may contain a biogas installation wherein conversion of the organ1c matter into biogas takes place. Through energet1c coupling of the l1berated biogas, the process according to the invention may be designed to be largely self-suff1cient as regards energy.
In the above descr1bed process management, the mixture of substances containing organ1c matter is subjected to a so-called hydrolysis wherein, through cooperation of air and leaching fluid, the organ1c material is dissolved and acidified as a result of aerob1c, thermophil1c heating by the air and carried off by the leaching fluid. I.e., decomposition of the organ1c constituents takes place as a result of setting a certain humidity and•supplying clean air.
Further processing of the mixture of substances provides for drying of the residue in accordance with the invention. Such drying may be effected at minimum energet1c expense by aerob1c, thermophil1c heating of the residue in the reactor. To this end, the mixture of
substances may either be subjected to appl1cation of clean air in the reactor, so that by the resulting aerob1c heating water vapor is discharged via the supplied air,' and the residue is dried. Drying and hydrolysis in one single reactor is, however, under the condition of batch-type operation wh1ch should be viable only in smaller installations. In larger-sized installations a separate reactor (dryer) is provided for aerob1c, thermophil1c heating of the residue from hydrolysis. As a matter of fact, these two reactors may also be arranged behind each other in n-fold succession in a single container, so -that several hydrolysis/drying steps may follow in succession.
The energy balance of the installation may be further improved if the laden leaching agent of a purif1cation of sewage water is supplied. The latter may contain a biogas installation in wh1ch conversion of the organ1c matter into biogas takes place. Through energet1c coupling of the l1berated biogas, the process according to the invention may be designed to be self-suff1cient as regards energy.
It is quite part1cularly advantageous if the solid fraction thus treated is supplied to a compacting step following hydrolysis and/or aerob1c drying. Here the solid matter presenting a certain part1cle diameter is pressed into a predetermined geometr1cal shape, for example pellets or briquets.. This compacting step results in further -dewatearing of the mixture of substances to be treated, so that following compacting a dry-stable body is present wh1ch cannot be eluted any further.
This body may, for example, be stored as a substitute fuel being an alternative for fossile energy carriers, or in a garbage dump.
The main appl1cation of the process according to the invention presumably resides in the treatment of waste matter; in principle the process may, however, also be applied for any other mixture of substances including organ1c constituents.
As a washing agent, water is customarily used wh1ch is recycled in the process of the invention. The air for hydrolysis and thermophil1c drying of the mixture of substances may be guided in counterflow to the mixture of substances but also in parallel flow.
Further advantageous developments of the invention are the subject matters of the further subclaims. In the following, preferred embodiments of the invention are explained in more detail by way of schemat1c drawings, wherein:
Fig. 1 is a sectional view of a reactor in wh1ch hydrolysis of a mixture of substances containing organ1c constituents takes place;
Fig. 2 shows a reactor for performing aerob1c, thermophil1c drying;
Fig. 3 shows an installation having a plurality of hydrolysis and drying reactors in accordance with Figs 1 and 2 arranged in sequence;
j
Fig. 4 shows a dev1ce having a plurality of reactors for hydrolysis and/or drying arranged in sequence in a common container;
Fig. 5 is a top view of the dev1ce of Fig. 4; and
Figs. 6 and 7 show alternative embodiments of a reactor.
Fig. 1 shows a process diagram explaining the process of the invention and the dev1ce for carrying out the process. Accordingly, the aerob1c hydrolysis (aerob1c biogen1c reaction and percolation) takes place in a reactor 1 to wh1ch the mixture of substances 2 to be processed is supplied through a material feeding means 4. The mixture of substances to be processed contains a large proportion of structured material and organ1c matter. The like mixtures of substances occur, for example, in household waste, biolog1cal waste, industrial waste etc..
The reactor 1 is designed as a closed container, so •that the material flows descr1bed in more detail hereinbelow are supplied via lock means, valve means etc. .
The reactor 1 proper preferably is a steel or concrete container that is supplied from above with the mixture o.f substances (residual waste) in the shown embodiment.
A substantial proportion of the organ1c fraction of the mixture of substances consists of short-chained compounds that, are mostly absorbed on a surface. If this surface is surrounded by a flow of warm water, primarily non-soluble compounds are also,hydrolyzed and washed out. The hydrolysis degree depends on the dwelling time in the reactor 1. The smell-intensive components of the mixture of substances and the hydrolysis products are well water-soluble and may be washed out. By percolation one therefore achieves a reduction of the organ1c matter and a deodorization of the mixture of substances. Together
with the leaching fluid (process water), fine sand part1cles are furthermore carried off. The reactor 1 is closed so as to be'smell tight, and the exhaust air is deodorized in the manner descr1bed more closely hereinbelow.
During percolation, process air is additionally supplied, whereby the phys1co-chem1cal effect of water extraction is enhanced by intensifying the bacterial decomposition. In the aerob1c environment, the m1croorganisms begin to.excrete exoenzymes wh1ch split part1cle-shaped polymer components into monomers and solubilize them.
During percolation, approx. 10% of the inert substances (glass, ceram1c, sand) are l1berated wh1ch are discharged together with the leaching fluid. Separation takes place inside a sand sifter wh1ch at the same time allows for supplementary rinsing for sand washing.
In the embodiment in accordance with Fig. 1, the charging means 4 is positioned at the upper end section of the- reactor 1 when viewed in the direction of gravity.
In the lower range of the reactor 1 at least one discharge means 6 is formed through wh1ch the processed and biolog1cally decomposed mixture of substances may be withdrawn from the reactor 1.
The-reactor 1-'moreover comprises below the discharge means 6 (representation of Fig. 1) a collector 10 wh1ch is separated from a reaction chamber 12 by a sieve floor 8. The discharge means 6, wh1ch shall be descr1bed in more detail hereinbelow, is designed such that the mixture of substances resting on the sieve floor 8 is discharged from the reactor in a layered configuration,
and the openings of the sieve floor 8 are kept unobstructed..
The collector 10 commun1cates with an air connection duct 14 and a leaching fluid exit 16. In the head area of the reactor 1 another air connection duct 18 and a leaching agent distr1butor 20 are arranged.
The leaching fluid (water) used for percolation or extraction of the organ1c constituents of the mixture of substances is fed into the reactor through the distr1butor 20 and withdrawn through the exit 16. For the purpose of a simplified flow management, the floor 22 of the reactor 1 is inclined towards the exit 16, so that the leaching fluid gathers in the range of the exit 16.
The lower air connection duct 14 in the
representation of Fig. 1 is connected with air conveying means 24. Depending on the design of the air conveying means (fan, compressor) , a flow 25 from the lower air connection duct 14 to the upper air connection duct 18 or a flow 27 in a reverse direction from the upper air connection duct 18 to the lower air connection duct 14 may be adjusted inside the reactor 1. I.e., -depending on the design of the air conveying means 24, air flows through the mixture' of substances received in the reactor 1 from bottom to top or from top to bottom in the representation according to Fig. 1.
The flow of leaching fluid takes place in the direction of gravity, namely, from the distr1butor 20 disposed in an upper location in the reactor 1 towards the exit 16.
The leaching fluid exiting from the reactor 1 is treated by means of a sewage treatment' dev1ce 26
(anaerob1c filter) descr1bed in more detail in the following, and then recirculated to the distr1butor 20.
The residue resting on the sieve floor 8 is withdrawn as discharge material 2B through the discharge means 6 and either supplied to further processing as a product 30 or, in turn, recycled to the charging means 4 als circulation material 32. The separation of the discharge material 28 into product 30 and/or circulation material 32 takes place through a suitable apportioning means 34 wh1ch may, for example, have the form of a slide gate, trap, distr1buting guide etc..
I.e., by means of suitable adjustment of the apportioning means 34 a part of the discharge material 28 may be recirculated into the reactor 1 als circulation material 32 and may there be utilized for inoculation of the mixture of substances and thus for accelerating the biolog1cal decomposition.
By circulating all or part of the mixture of substances with the aid of the conveying means, shear forces are moreover introduced into the circulation material, so that surfaces of the mixture of substances are reformed and part1cles are separated into f1bers.
For a better understanding, the above descr1bed single components of the dev1ce according to the invention shall now be explained in more detail.
The incoming mixture of substances 2 has in advance been treated mechan1cally in a known manner so as to have a predetermined maximum part1cle size. This processed mixture of substances 2 is supplied via suitable conveying means, for example conveyor belts 36, to the charging means 4 whereby a distr1bution of the mixture of
substances 2 across the reactor cross-section takes place. In the shown embodiment the charging means 4 includes a transversal conveyor 8 whereby the mixture of substances is distr1buted in the plane of drawing and in a transversal direction relative to the plane of drawing, and supplied to the reactor 1 by material hoppers 40 wh1ch are distr1buted over the cross-section.
By actuating the material hoppers 40 or the transversal conveyor 38, the mixture of substances 2 is introduced into the reactor 1 in layers, so that pract1cally n-layers 4.2 are arranged on the sieve floor 8 on top of each other.
The filling height H of the reactor 1 is selected such that the distr1butor 20 for the leaching fluid is located above the bulk material. The distr1butor 20 may, for example, present a multipl1city of spraying heads 44 distr1buted across the reactor cross-section, whereby the leaching fluid may be distr1buted homogeneously over the topmost layer 42.
In che embodiment represented in Fig. 1, the discharge means 6 has the form of a horizontal conveyor designed such that the respective bottom layer of the mixture of substances resting on the sieve floor 8 may be discharged in a horizontal direction. In the represented reactor 1 the discharge means 6 has the form of a sliding or scraper floor as descr1bed, for example, in WO 95/20554 Al. The -like sliding floors are, for example, employed in sewage sludge silos, composting installations etc. and are known from the prior art, so that only the essential components shall be descr1bed hereinbelow.
In accordance with Fig. 1, the sliding floor includes a plurality of conveyor wedges 46 spaced apart in a
horizontal direction (view of Fig. 1) and arranged on a thrust rod 48. The-thrust rod 48 may be moved reciprocally, in parallel with arrows 52, 54 in Fig. 1 with the aid of a hydraul1c cylinder 50 or some other drive means.
The front surfaces of the conveyor wedges 46 facing the discharge opening have the form of vert1cal surfaces 56, whereas the rear surfaces are inclined surfaces 58. Through corresponding control of the hydraul1c cylinder 50 the thrust rod 48 is period1cally moved back and forth, wherein during the movement of the thrust rod 48 in the direction or. arrow 52 (to the left in Fig. 1) the mixture of substances of the lowest layer slides upwards along the inclined surface 58 and comes to lie in the space behind the respective conveyor wedge 46. During the subsequent return movement of the thrust rod 48 in the direction of arrow 54, this material is carried along by the vert1cal surface 56 and conveyed to the right to the neighboring conveyor wedge 46 or to the discharge opening. I.e., the height of the conveyor wedges 46 determines the height of the layers of the discharged mixture of substances. In order to maintain the extracting conditions in the reactor 1 constant, the layer th1ckness of the discharge material about corresponds to the layer th1ckness of the material supply, with the filling height H accordingly remaining essentially constant.
As was already mentioned at the outset, a part of the discharge material 28 may be recycled to the conveyor means 36 or directly to the charging means 4 as inoculation material (circulation material 32) . In principle it is also poss1ble to use all of the discharge material 28 als circulation material 32, in wh1ch case the mixture of substances passes through the reactor I
several times and is 'only discharged as product 30 following, for example, 4 runs.
The sieve floor 8 arranged underneath the discharge means 6 has a mesh size Z selected as a function of the composition and part1cle size of the mixture of substances to be processed. The construction of the thrust rod 48 and of the conveyor wedges 46 is selected such that the sieve floor 8 is cleaned by the reciprocating movement of the scraper floor, so that an obstruction of the meshes may be prevented.
Layered discharge of material results in a movement of layers of the nuxture of substances from top to bottom through the reactor 1 in a vert1cal direction (Fig. 1) .
As was already mentioned above, the air conveying means 24 may have the form of a fan or compressor, so that different directions of air flow may be adjusted in the reactor 1. In either case the entry and exit ranges of the reactor 1 are selected such that the air flows through the layered mixture of substances while being distr1buted over the entire reactor cross-section. This air flow is ind1cated by dashed lines in the representation of Fig. 1.
The leaching fluid flows through the layered mixture of substances along the solid-line arrows from top to bottom and enters, laden with organ1c matter, into the collector 10 through the sieve floor 8. The laden leaching fluid 60 is withdrawn via the exit 16 and supplied to the sewage treatment dev1ce 26. The latter comprises a foreigr, matter separator 62 in wh1ch foreign matter 64 such as, for'example, sand, pebbles, suspended matter, float matter etc.. are separated out. Such foreign matter separators may, for example, comprise a settling
tank and a skimmer for separating out the mentioned foreign matter 64..
The leaching fluid freed from the foreign matter and containing colloidal organ1c compounds in aqueous phase is then supplied to an anaerob1c fermeter 66, for example a biogas or digestion tower installation. Metabol1c end products produced in this anaerob1c waste water treatment are methane and carbon dioxide and in some cases small amounts of hydrogen sulfide. This biogas obtained as a decomposition product may be converted into electr1city and heat in suitable block-type thermal power stations. A part of the energy recovered from the biogas is returned into the process of the invention wh1ch is thus largely self-suff1cient as:regards energy.
Preliminary trials showed that in the treatment of one [metr1c] ton of supplied household waste, approx. 80 Nm* of biogas having an energy content of 6.5 kWh may be obtained.
In the above descr1bed embodiment a sewage water purif1cation plant is associated with the reactor. As an alternative, the leaching fluid might also be incorporated into .an existing sewage purif1cation plant, or be introduced directly into the sewers, or supplied to another treatment step. For the supply, fresh water or industrial process water or weakly loaded sewage water will be used in that case.
The anaerob1c fermenter 66 is followed immediately by a two-stage aerob1c aftertreatment 70, wherein digestion process water from the biogas installation is subjected . to an aftertreatment for minimizing the residual load, and nitrogen is eliminated.
Depending on load and legal regulations in force, the loaded sewage 72 thereby produced is supplied to a further treatment stage or directly introduced into the sewer system. The leaching fluid purified in the aerob1c biolog1cal stage 70 is then supplied to the reactor 1 by way. of the distr1butor 20. As is .ind1cated in Fig. 1, a partial flow of the digestion process water may be supplied directly from the anaerob1c fermenter 66 to the distr1butor while bypassing the 2-stage aerob1c biolog1cal stage 70, in order to exert a catalyt1c influence on biolog1cal decomposition in the reactor 1.
As a result of the flow management according to the invention inside the reactor 1, aerob1c hydrolysis takes place, with an aerob1c, thermophil1c heating occurring as a result of the air flowing through the mixture of substances 2 and the humidity of the mixture of substances wh1ch is adjusted by way of the leaching fluid, whereby the 'cells of the organ1c matter are split open and the l1berated organ1c substances are discharged by the leaching fluid.
Decomposition of the organ1c materials is due, on the one hand, to the aerob1c decomposition of the available carbon C into CC>2 (carbon1c acid) and on the other hand to leaching, out of the dissolved and acidified organ1c matter and removal by way of the leaching fluid. Due to the aerob1c, thermophil1c reaction and the simultaneous decomposition of the organ1c compounds, the temperature in the mixture of' substances rises (to approx. 40 to 50°C, for example) during the extracting step. As a result of this temperature increase water vapor is l1berated, wh1ch is discharged via the supplied air. This water vapor discharged together with the air may be supplied to the above descr1bed sewage water purif1cation as a condensate.
The air flowing off from the reactor 1 is laden with carbon dioxide as a decomposition product and with the water yapor produced by the heating. The exhaust air laden with organ1c components may be supplied to a biofilter wherein biolog1cal cleaning by means of aerob1c m1cro-organisms takes place.
As a leaching fluid initially pure water is used, wh1ch is made acid1c by salts dissolved during the aerob1c treatment following the startup of the installation and obtention of nearly stationary process parameters. The slight acidif1cation of the water enhances leaching of soluble organ1c, inorgan1c substances and water-soluble fatty acids.
As is moreover represented in Fig. 1, the mixture of substances 2 located inside the reactor 1 is subjected to intermittent pulses due to the reciprocating movement of the conveyor wedges 46, whereby shear, transversal and longitudinal forces are introduced into the mixture of substances and poss1bly formed flow channels of the leaching fluid and of, the air are destroyed. The magnitude of these forces is designed such as to be capable of destroying these channels and chimneys on the one hand, however not to result in destruction of the layered structure.
In the embodiment represented in Pig. 1 these pulses are brought about-'by the movement of the scraper floor; as an alternative, however, as is represented in Figs. 6 and 7, additional means for inducing shear .forces in the mixture of substances 2 and for destroying the channels might be employed, as represented in Figs. 6 and 7.
Following the above descr1bed hydrolysis, i.e. following decomposition of the organ1c constituents and extraction of these constituents by means of the leaching fluid, the discharge material 28 is supplied to a drying step. It was found to be. part1cularly advantageous if this drying takes place as aerob1c drying, for the residual humidity may then be reduced at minimum ene'rgy expense. The like aerob1c drying may be effected, for example, by interrupting the supply of leaching fluid through the distr1butor 20, so that nothing but air flows through the mixture of substances 2 following hydrolysis. As a result of flow through the humid mixture of substances 2, further aerob1c decomposition of the as yet available carbon C into carbon dioxide takes place. Moreover, similarly to hydrolysis, the mixture of substances is heated due to the m1crobial conversion and thereby water vapor is discharged by way of the flow of air passing through. Due to the aerob1c decomposition of the carbon and discharge of the water vapor, the residual humidity of the mixture of substances is reduced, with the desired proportion of dry substrate being adjustable in a simple manner through the duration of aerob1c drying.
In the above descr1bed embodiment, hydrolysis and aerob1c drying are thus performed in a single reactor 1. I.e., the reactor 1 may be used both for drying and percolation without any modif1cation, so that a simple structure of the installation is ensured.
As an alternative, it would be poss1ble to arrange downstream from the reactor 1 of Fig. 1 a dryer in accordance with Fig. 2 to wh1ch the discharge material 28 from the reactor 1 is supplied. This aerob1c dryer 74 essentially has the same construction as the reactor 1 of Fig. -1, i.e. the mixture of 'substances, in this case the
discharge material 28, is introduced via a charging means 4 into a container.provided with lock means, and following completed aerob1c drying is discharged via a discharge means 6. Other than the above descr1bed reactor 1, the dryer 74 has a plurality of air connection ducts 14 arranged above each other perpend1cularly to the plane of drawing, so that the air may be injected in sheet form. The drying air, in turn, may be guided in counterflow or in parallel flow with the flow of the mixture of substances and is accordingly supplied and discharged through air connection ducts 14, 16.
Other than the reactor of Fig. 1, the dryer 74 of Fig. 2 does not include a distr1butor 20 for the appl1cation of leaching fluid.
In the aerob1c dryer 74, in turn, partial recirculation of the dry material. 76 present at the exit from the dryer 74 as circulation material 78 and/or discharge of a dried product 80 is provided for. The mixture of substances to be dried passes through the dryer 74, once again preferably in a layered form, with channel formation being suppressed by shear, transversal and longitudinal fcrces applied in the form of pulses. This 2-stage process might, of course, be carried out by means of two reactors arranged in sequence in accordance with Fig.. 1, with hydrolysis in the first reactor taking place through supplying air and leaching fluid, whereas in the second, downstream reactor 1 only aerob1c drying as a result of supplying air takes place.
Fig. 3 shows an embodiment wherein three reactors la, 1b, 1c in accordance with Fig. 1 are combined with three dryers 74a, 74b, 74c in accordance with Fig. 2. Accordingly, a common conveyor means 36 is associated to the three reactors la, 1b, l"c, whereby the mixture of
substances 2 may be supplied to'the single reactors la, 1b, 1c. By means of suitable apportioning means 34, in turn, the flow of material to the single reactors la, 1b, 1c may be adjusted.
.The discharge material 28a, 28b, 28c from the single reactors la, 1b, 1c may in turn be recirculated by way of the apportioning means 34 als circulation material 34 or, in turn, supplied as product 30 to further processing, or as discharge material 28 to the aerob1c drying. Herein the discharge material 28 from reactors la, 1b, 1c is supplied to the dryers 74a, 74b, 74c through conveyor means 84 and suitable apportioning means 34.
In the schemat1c representation of the installation in accordance with Fig. 3 it is furthermore provided that the mixture of substances 2 is also supplied to drying directly, i.e. while bypassing the reactors 1. This is the case, for example, when the mixture of substances present already includes a considerable proportion of dry substance, so that no more wet washing takes place.
The discharge material from the dryers 74, i.e. the dry material 76a, 76b, 76c is then either further processed as dry-product 86, again supplied to drying as circulation material 78, or supplied to means 90 for dewatering and/or compacting as an -intermediate product 88.
The means 90 is also used for further processing of the discharge material from the reactors/dryers represented in Figs. I, 2. The means 90 may, for example, have the form of an extruder or a dryer/extruder press so that as a result of the mechan1cal action and the heat generated by the pressure buildup, further dewatering or drying of the intermediate product 88 takes place.
Inside the means 90 the extracted residual waste is adjusted to a dry-substance content of > 60%. In a preferred embodiment the means 90 moreover contains a high-performance press whereby the extracted, dewatered material may be pelleted. Herein densities of 1.7 t/m3 are attained. The energy expense for producing the pellets amounts to -approx. 1% of the energy content of the pellets when one assumes a mean energy content of 14 MJ/kg.
Depending on the design of the means 90, the dewatered final product 52 may be present as a pellet, briquet or in another compacted form. By the above descr1bed process steps a product may be produced wh1ch cannot be eluted further, has no breathing activity, and is characterized by a large proportion of dry substance, wherein it is not necessary to employ thermal energy from the outside for drying in contrast with the known process.
The material dewatered with the aid of the means 90 may be subjected to subsequent drying by means of composting or belt drying. Conventionally post-rotting was previously connected after a mechan1cal-biolog1cal treatment of waste in order to attain additional decomposition of organ1c material and drying of the leached residue. Post-rotting may readily take place in an exposed pit. The proportion of biogen1c material is suff1ciently high even after percolation, so that the rotting temperature will rise to 70°C within 4 to 6 days. Within 10 to 16 days the residue thus treated attains a dry substance content of up to 80%. As waste heat for drying of the percolation residue would be available in the above descr1bed process owing to biogas extraction and conversion into electr1city in a gas engine, a space-
saving drying process may also be employed for post-rotting.
The arrangement represented in Fig. 3 is selected when a continuous operation is desired. At high throughputs, the installation may be expanded by adding further modules (reactors 1, dryers 74).
The conveying means 36 and 84 and the apportioning means 34 (material.deflection) may be controlled such that the order of Charging, emptying or mixing (circulation material) of the single reactors, dryers may be changed in any desired order.
Fig. 4 shows an embodiment wherein a container 96 is separated into three chambers or reactors la, 1b, 1c by two partition walls. These chambers correspond to the means in accordance with Fig. l and in accordance with Fig. 2 wherein the hydrolysis and/or the aerob1c drying may be carried out.
To the tight container 96 a common conveyor means 36 is associated whereby the mixture of substances 2 to be processed is supplied to the container 96. By the common conveyor means 36 the mixture of substances is guided via the apportioning means 34 to a transversal conveyor 38 having the form of a distr1butor crane in the shown embodiment. The latter includes a material chute 40 wh1ch is movable across the entire cross-sectional area of the container 96 by means of the distr1butor crane (transversal conveyor 38). Hereby it is ensured that the partial spaces la, 1b, 1c of the container 96 may be charged with the layered mixture of substances 2.
Discharging the treated mixture of substances (discharge material 28 or dry material 76) takes place
hrough a discharge means 6 wh1ch may, for example, be designed like the one in Fig. 1. In accordance with the variant-s represented in Fig. 4, it is also poss1ble to form a plurality of discharge means 6a, 6b, 6c in laterally adjacent arrangement in the range of the floor of the container 96. In the shown embodiment the container 96 has the form of a multiple-chamber dryer designed to have air connection ducts 14, 18, with only the air connection duct 18 arranged on top being shown in Fig. 4. In this variant, as well, it is provided that the air is guided to the mixture of substances in parallel flow or in counterflow. The container 96 might, of course, also be designed as a reactor having a plurality of partial chambers. The reactors/dryers represented in Figs. 1 to 3 may, of course, also be designed to include a plurality of laterally adjacent discharge means 6.
. The discharge material 28 may be returned to the conveyor means 36 via the apportioning means 34 as circulation material 32, or, however, be discharged as product 30.
Fig. 5 shows a top view of the container 36 of Fig. 4 explaining distr1bution of the mixture of substances 2. Accordingly, the mixture of substances 2 is charged on the conveyor means 36, for example a conveyor belt, and thereby supplied to a distr1butor crane 38 that is movable in the direction of arrows 100, 101 above the partition walls 98, 99. The distr1butor crane 38 carries one movable or a plurality of stationary material chutes 40, so that the entire width (vert1cal Fig. 5) of the partial chambers la, lb, 1c may be covered.
The processed mixture of substances is discharged from the container 96 in the direction of arrow 102, and this discharge material 28 is carried off through
suitable conveyor means either as product 30 or as circulation material 32. The latter is transported back to the conveyor means 36 by a conveyor belt and then once more charged into one of partial spaces la, 1b, 1c.
In the above descr1bed embodiments, formation of chimneys was prevented by the forces introduced into'the bulk material through the discharge means 6, wh1ch caused a wave-type vert1cal displacement in the heap material and thus resulted in reformation of the heap material surfaces and destruction of channels. Depending on the quality of the mixture of substances to be processed, the shear forces thus introduced may, however, sometimes be too weak for bringing about the required mechan1cal decomposition of the bulk material. In the above descr1bed reactors 1 the proportion of the circulation material 32 is then increased, so that the shear forces required for material decomposition are then introduced by way of the conveyor elements for conveying the circulation materis.! 32.
With respect to energy and material expenditure, this variant is still substantially more favorable than the prior art descr1bed at the outset, wherein agitators are used inside the reactor in order to introduce the shear forces.
The expenditure in terms of energy and apparatus technology may be further reduced if the reactor/dryer according to the -invention is -designed in the manner descr1bed in Figs. 6 or 7.
In the embodiments descr1bed in Figs. 1 and 2, the process air was injected into the bottom portion of the reactor 1 or dryer, respectively, through one or a plurality of air connection 'ducts 14 and then enters
through the sieve floor 8 into the heap material (bulk material). In contrast, in the embodiments represented in Figs. 6 and 7, the process air is injected through a multipl1city of lances 110 distr1buted over the cross-section of the reactor 1, the nozzles 112 of wh1ch open into the lower range (view of Figs. 6, 7)of the bulk material 114. The lances 110 extend through the sieve floor 8 and the discharge means 6 - in the present case the sliding floor.
The lances 110 for process air or pressurized air are each connected through a control valve 116 to a pressure line 118 wh1ch opens into a pressure accumulator 120. The latter is connected to a compressor 122 through wh1ch fresh air or air 124 recycled from the exhaust air treatment (biofilter) may be taken to the system pressure, i.e. the pressure in the pressure accumulator 120. The control valves 116 are connected to a process control means 126 and may thus individually be controlled open and closed, respectively.
The opening cress-section of the control valves 116 may be continuously variable depending on the process control means 126, so that the pressure of the process/pressure gas is variable:
The system pressure in the pressure accumulator 120 is preferably adjusted to a pressure of more than 4 bar. Upon complete opening of a control valve 116 of a lance 110, pressurized -air 128 exits from the nozzle opening in an upwardly direction (view of Figs. 6, 7) and flows through the bulk material 114 in a vert1cal direction at the maximum pressure, with the arrows in Figs. 6, 7 ind1cating that the pressurized air 128 is also deflected in the transversal direction. The bulk material 114 is partially whirled uo or flui'dized in the range through
wh1ch the pressurized air 128 flows, so that the surfaces of the heap material are reformed and channels are destroyed. I.e., by the injected pressurized air a partial undulating movement 130 is generated in the bulk • material 114, wh1ch moves away from the nozzle 112 of the respective lance 110 through the bulk material 114 in an upwardly direction. Due to this undulating movement, a relative movement of the mixture of substances is induced, so that the surfaces of the part1cles are torn open and thus the mass transfer area is increased. As the pressurized air is only injected in pulses, the bulk material 114 again collapses after the control valves 116 are closed, so thac again shear forces are introduced into the bulk material 114 wh1ch result in repeated reformation of the surfaces and in destruction of channels. The laden air 123 exiting from the reactor 1 is supplied to a biofilter.
Owing to the injected pressurized air, bas1cally two effects are attained. For one thing shear forces are introduced in the above descr1bed manner into the bulk material 114, on the other hand the process air required for hydrolysis and/or drying is also supplied, so that the introduction of shear forces and feeding of process air are pract1cally combined. Model calculations have shown that on account of the pressurized air connection duct according to the invention, the energy requirement may be reduced by up to in excess of 50% in comparison with a conventional reactor including an agitator.

The process control 126 and the control valves 116 are designed such that the px-essure of the process/pressurized air may be varied over time, so that for example over a predetermined time interval process air only having a low pressure (0.5 bar) is supplied wh1ch is required for drying or hydrolysis, however does
not result in considerable introduction of shear forces into the bulk material 114. Depending on the bulk height and the quality of the mixture of substances to be processed, pressurized air is then intermittingly supplied at a comparatively high pressure (> 4 bar) in order to introduce the above descr1bed shear forces and avoid'a formation of channels.
The valves 116 of the multipl1city of pressure lances 110 of the reactor 1 may also be controlled consecutively, so that an "expansion wave" propagating in
i
parallel with the plane of drawing or perpend1cularly to the plane of drawing in the representation according to Pigs. 6 and 7 passes through the bulk material.
For the rest, the embodiment represented in Fig. 6 corresponds to the above descr1bed embodiments. I.e., the mixture of substances 2 is introduced into the reactor 1 by way of the charging means 4 from above in a layered configuration and migrates through the latter, with the layered structure remaining substantially unchanged due to the supply of pressurized air and the resulting partial fluidization of the bulk material. The processed mixture of substances is then discharged via the discharge means 6, i.e. a. sliding floor, and supplied to the further treatment steps.
In the embodiment represented in Fig. 7, the mixture of substances 2 is supplied at the left-hand front face of the reactor 1 in the representation of Fig. 7 and is at the opposite side of the reactor 1 discharged in a downwardly direction. Accordingly, the mixture of substances migrates through the reaction chamber 12 having a vert1cally arranged layered structure as is designated by reference symbols 1 to ln. I.e., the mixture of substances moves through the reactor in a

horizontal direction (1) while being displaced through . the reactor in a vert1cal direction in the embodiment represented in Fig. 6.
For the rest, che embodiments represented in Figs. 6 and 7 correspond to the above descr1bed embodiments, so that reference is made to the above explanations with regard to the remaining components. For the sake of simpl1city, the same reference numerals were used in Figs. 6 and 7 for corresponding components as in Figs. 1 to 5.
In simple words, in the embodiments represented in Figs. 6 and 7 the agitator used in the prior art was replaced with a "pressurized air agitator", with the pressure for the pressurized air being selected such that the layered structure is essentially preserved. Thanks to the poss1bility of individually controlling the control valves 116 that are distr1buted over the cross-section of the reactor 1, the bulk material 114 may purposely be subjected to pressure pulses, so that the introduction of shear forces may be applied depending on the process, i.e., appl1cation of pressurized air bzw. process air may be effected as a function of the quality of the mixture of substances to be processed and of the dwell time in the reactor 1. The appl1cant reserves the right of directing independent sets of claims to the variants
i
represented in Figs. 6 and 7 and 1 to 5.
A process for-'treating a mixture of substances containing structured constituents and organ1c matter, and a dev1ce for carrying out this process are disclosed. In accordance with the invention, the mixture of substances is subjected to pulse-type or-period1cal appl1cation of force, so that the formation of flow
channels for a leaching fluid or process air in a bulk material may be prevented.

We Claim:
1. a process for treating a mixture of substances (2) containing structured
constituents and organic matter which is received in the form of bulk material
and subjected to aerobic decomposition or aerobic drying in a reactor (1) by
means of a flow of process air therethrough and/or addition of a leaching
fluid so that the soluble organic constituents are discharged, characterised in
that said mixtures of substances (2) is subjected to pulse-type or periodical
application of pressurised air having a pressure of more than 2 bar and
directed approximately perpendicular to and/or in parallel with the direction of
displacement of said mixture of substances so as to introduce shear forces
and prevent channel formation.
2. A process as claimed in claim 1, wherein the compressed air or the heated
air is directed through jets (112) in the upper part and/or lower part of the
reactor (1).
3. A process as claimed in claim 2, wherein the heated air and the compressed
air are directed through the same jets (112).
4. A process as claimed in any one of the preceding claims, wherein the
reactor (1) remains in continuous operation and the mixture is taken through
the reactor (1) approximately parallel or at right angles to the heated air.
5. A process as claimed in any one of the preceding claims, wherein the
flushing-out liquid enters the reactor (1) through a distributor (44) in the top
part of the reactor (1).
6. A process as claimed in any one of the preceding claims, wherein the
compressed air is applied at a pressure of greater than 2 bar and preferable
greater than 4 bar.
7. A process as claimed in any one of the preceding claims, wherein the
treated mixture (2) is removed via an opening (6) fixed into the lower part of
the reactor (1), through which all or some of the force can be applied to the
waste heap.
8. A process as claimed in any one of the preceding claims, wherein the air-
induced breaking down is supplemented by air-drying of the mixture.
9. A process as claimed in claim 3, wherein the mixture goes through a series
of breaking-down and drying procedures one after the other.
10. A process as claimed in any one of the preceding claims, wherein
compression of the mixture is added to its breaking-down and/or air-drying.
11. A device, in particular for implementing the process as claimed in any of the
preceding claims, comprising a reactor (1, 74, 96) having associated a
charging means (4) for introduction of a mixture of substances, wherein
inlets (14, 18) for introducing process air are arranged in the bottom portion
and/or in the head portion of said reactor (1, 74, 96), and/or a distributor (20)
for leaching fluid is arranged in the head portion of the said reactor (1, 74,
96) characterised by a pressurised air system (6, 112) whereby pressurised
air of more than 2 bar may be supplied in the form of pulses or periodically
for decomposition of said bulk material (114), and by discharge means (6) in
the bottom portion of said reactor (1, 74, 96).
12. A device as claimed in claim 11, wherein the air-compression equipment has
jets (112) leading into the lower part of the reactor (1) that are connected to a
pressure chamber (120) of an air compressor (122).
13. A device as claimed in claim 11 or claim 12, wherein a control mechanism is
connected to the air-compression equipment whereby the pressure of the
compressed air or the heated air can be varied.

14. A device as claimed in any one of claims 11 to 13, wherein compressed air
and heated air can be applied together through the air-compression
equipment.
15. A device as claimed in any one of claims 11 to 14, said device being
provided with gas cleaning equipment for cleaning and bringing back the
heated and/ or compressed air.
16. A device as claimed in any one of claims 11 to 15, wherein equipment is
installed in the lower part of the reactor (1, 74, 96) whereby turbulence is at
least partially created.
17. A device as claimed in any one of claims 11 to 16, wherein several reactors
(1, 74, 96) are connected in series, so that a system of conduits (4) common
to several reactors (1, 74, 96) is installed, into which the mixture (2) to be
treated can be fed.
18. A device as claimed in any one of claims 11 to 17, said device being
provided with compacting equipment (90) for compressing, removing water
and shaping the treated mixture.

Documents:

in-pct-2001-477-del-abstract.pdf

in-pct-2001-477-del-claims.pdf

in-pct-2001-477-del-correspondence-others.pdf

in-pct-2001-477-del-correspondence-po.pdf

in-pct-2001-477-del-description (complete).pdf

in-pct-2001-477-del-drawings.pdf

in-pct-2001-477-del-form-1.pdf

in-pct-2001-477-del-form-13.pdf

in-pct-2001-477-del-form-19.pdf

in-pct-2001-477-del-form-2.pdf

in-pct-2001-477-del-form-3.pdf

in-pct-2001-477-del-form-5.pdf

in-pct-2001-477-del-gpa.pdf

in-pct-2001-477-del-pct-210.pdf

in-pct-2001-477-del-pct-304.pdf

in-pct-2001-477-del-pct-409.pdf

in-pct-2001-477-del-pct-416.pdf

in-pct-2001-477-del-petition-137.pdf

in-pct-2001-477-del-petition-138.pdf

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Patent Number

219623

Indian Patent Application Number

IN/PCT/2001/00477/DEL

PG Journal Number

26/2008

Publication Date

27-Jun-2008

Grant Date

12-May-2008

Date of Filing

04-Jun-2001

Name of Patentee

MULLER, PATRICK

Applicant Address

Inventors:

#	Inventor's Name	Inventor's Address
1	WIDMER, CHRISTIAN
2	MULLER, PATRICK

PCT International Classification Number

C05F 17/02

PCT International Application Number

PCT/IB99/01950

PCT International Filing date

1999-11-04

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	198 51 306.2	1998-11-06	Germany
2	199 51 353.9	1999-03-03	Germany
3	199 51 306.2	1999-03-03	Germany