EP0456027B1 - Process for thermal regeneration of returned foundry sand and for treating dust formed during its circulation - Google Patents
Process for thermal regeneration of returned foundry sand and for treating dust formed during its circulation Download PDFInfo
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- EP0456027B1 EP0456027B1 EP91106468A EP91106468A EP0456027B1 EP 0456027 B1 EP0456027 B1 EP 0456027B1 EP 91106468 A EP91106468 A EP 91106468A EP 91106468 A EP91106468 A EP 91106468A EP 0456027 B1 EP0456027 B1 EP 0456027B1
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- Prior art keywords
- dust
- fluidized bed
- sand
- combustion
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
- B22C5/08—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by sprinkling, cooling, or drying
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S241/00—Solid material comminution or disintegration
- Y10S241/10—Foundry sand treatment
Definitions
- the invention relates to a method for the thermal regeneration of used sand accumulating in foundries according to the preamble of claim 1.
- Waste foundry sand as it occurs in the processing of used sand molds, must first be processed at least roughly, whereby large lumps of sand are broken up with mechanical means, such as hammer mills, castings are removed via magnetic separators and the dust components accumulated during mechanical processing are separated off using air classifiers before, after further mechanical treatment steps, if necessary, thermal treatment of the old sand can be carried out.
- Fluidized bed processes are used in a large number of industrial processes in which a fluidized bed is formed within a fluidized bed furnace consisting of dust or fine to coarse-grained solids and an inflow or fluidized gas blown in from below, in which both exothermic and endothermic processes take place.
- Dusty coal for example, is introduced into the fluidized bed as fine-grained solids for specifying exothermic reactions.
- a known fluidized bed process with an exothermic reaction in which, however, no fuel in the form of a solid substance is used for heating the fluidized bed, is the roasting of sulfidic ores, such as pyrites, galena or zinc blende within such a fluidized bed.
- Known Fluidized bed processes with endothermic reaction are drying, calcining, sintering of dusty to granular bulk material.
- a fluidized bed of introduced trickle material such as coal, garbage, metallic dusts or the like, is formed within the fluidized bed furnace in the region of the furnace floor for an exothermic combustion process.
- the furnace floor is designed as a gassing floor and has a discharge opening for the reaction product in the middle at the end of a conically tapering section.
- Free-flowing solids such as old-fashioned resin-containing sand, but also quartz sand or clay, are passed through a pipe system acting as a heat exchanger inside the fluidized bed furnace, in order to be finally fed to an external collecting container from which the regrind can then be drawn off.
- This known fluidized bed furnace arrangement is particularly suitable for processing or converting specific heavy substances, e.g. for roasting sulfidic ores.
- the known method can be used with a correspondingly modified device structure for processing and converting specifically light substances, e.g. of resin-containing binders or binder residues, such as those adhering to used sand.
- a device is known in which the material taken off is subjected to a wind sifting, the air being heated directly by at least part of the solid material before being brought together with the material. After merging with the withdrawn fluidized bed material, the air absorbs heat from it, after which it is fed back to the combustion chamber of the fluidized bed combustion system with the fine fraction of the layered material via a delivery pipe additionally subjected to air.
- the present invention has for its object to provide a method for inerting dusts from the old sand accumulating in foundries, such as in the reprocessing by separating cast iron and sand, sieving, classifying, mixing and the like Mechanical comminution measures arise, while at the same time minimizing the energy balance.
- the mechanical treatment of the sand preceding this thermal treatment enables the dusts to be easily separated for the process sequence according to the invention, for example by suctioning and separating them in filter systems known per se.
- the dusts consist essentially of a fine-grained quartz fraction, optionally made of other inorganic substances such as clay particles and a not inconsiderable organic component made of dusty resin compounds. Such dust mixtures would have to be brought to special landfills if they were not returned to the process cycle, which means that they can only be disposed of at considerable expense.
- the inertization of the dusts according to the invention makes it unnecessary to place them in hazardous waste landfills and further improves the energy balance for the thermal treatment step of the old sand.
- the dusts such as those obtained from the sand cycle of a foundry, are blown in easily over the bottom of the fluidized bed furnace into the fluidized bed by means of heat exchangers preheated air as a means of transport, which serves as the inflow gas for the fluidized bed.
- the inertization of the blown-in dust, insofar as these are incombustible components thus takes place practically simultaneously with the thermal regeneration of the old foundry sand.
- the waste heat from the fluidized bed furnace is used to preheat the blowing air.
- the interior of the fluidized bed furnace is divided into the lower fluidized bed 4 and the upper post-combustion chamber 3, the fluidized bed being separated from the inflow chamber for the fluidizing gas by a sieve plate or similar perforated plate in the usual way.
- the used sand 1 obtained from the mechanical pre-cleaning, not shown, which has previously been freed from the fine-grain component or dusts accumulated there, is introduced into the fluidized bed furnace via a metering device 2 in the manner shown.
- the used sand itself thus specifies the fluidized bed 4, the residence time of which is controlled within the furnace in such a way that the combustible binder residues still adhering to it are burned within the fluidized bed 4, optionally calcined.
- the regenerate 5 resulting from this thermal regeneration is discharged from the furnace in order to be available for the new formation of foundry molds.
- a layer of sand is first heated in the furnace until a predetermined target temperature of generally 500 ° C. to 900 ° C. is reached using external energy via a fuel gas, which can be metered via a valve 15 into an inflow accelerated by means of fan 14 is given.
- a fuel gas which can be metered via a valve 15 into an inflow accelerated by means of fan 14 is given.
- the dust obtained from the sand cycle is introduced into the fluidized bed 4 from below via a dust feed 6 and a metering feed 7 and an intermediate silo 9.
- Air which has been preheated by means of a heat exchanger 11, serves as a means of transport for the dust through a pipeline 10.
- the heat exchanger 11 is connected on the one hand to the outlet of the afterburning chamber 3 of the fluidized bed furnace and, on the other hand, is supplied with fresh air via a fan 8, which then leaves the heat exchanger in the desired preheated form via the pipeline 10.
- the cooled hot air from the fluidized bed furnace is fed from the heat exchanger 11 to a separator 12, which can be, for example, a cyclone separator or a suitable filter device by means of which the inertized or calcined dusts are cleaned into the environment by a fan 13 before the exhaust air is discharged.
- the dust with its organic combustible constituents is metered into the pipeline 10 via special lances or the like to form a combustible dust-air mixture.
- the fuel gas can be throttled or completely switched off via the valve 15, so that the heating of the fluidized bed and the maintenance of the desired temperature in the same takes place exclusively via the dust.
- the temperature-dependent dosage required for this can be done via a feedback circuit known per se can be controlled.
- Inertized dust obtained in the separator 12 is discharged from the described pipe system via a cellular wheel sluice 16 or the like and collected in a container 17.
- a pelletizing mixer can be added to this collecting vessel, for example, or it can be designed as such.
- the dust which is fed through the fluidized bed 4 and which is fed through the line 10 is subjected to afterburning in the afterburning chamber 3, so that it is ensured in any case that it leaves the fluidized bed furnace in a completely inert form.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
- Crucibles And Fluidized-Bed Furnaces (AREA)
- Gasification And Melting Of Waste (AREA)
- Processing Of Solid Wastes (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Fluidized-Bed Combustion And Resonant Combustion (AREA)
Abstract
Description
Die Erfindung bezieht sich auf ein Verfahren zur thermischen Regenerierung von in Gießereien anfallendem Altsand gemäß Oberbegriff des Anspruches 1.The invention relates to a method for the thermal regeneration of used sand accumulating in foundries according to the preamble of claim 1.
Derartige Verfahren sind ganz allgemein bekannt. Gießerei-Altsand, so wie er bei der Aufbereitung benutzter Sandformen anfällt, muß zunächst zumindest grob aufbereitet werden, wobei mit mechanischen Mitteln, wie Hammermühlen große Sandklumpen zerschlagen werden, über Magnetabscheider Gußreste ausgetragen werden und über Windsichter die bei der mechanischen Aufbereitung anfallenden Staubkomponenten abgetrennt werden, bevor nach gegebenenfalls weiteren mechanischen Behandlungsstufen eine thermische Aufbereitung des Altsandes vorgenommen werden kann.Such methods are generally known. Waste foundry sand, as it occurs in the processing of used sand molds, must first be processed at least roughly, whereby large lumps of sand are broken up with mechanical means, such as hammer mills, castings are removed via magnetic separators and the dust components accumulated during mechanical processing are separated off using air classifiers before, after further mechanical treatment steps, if necessary, thermal treatment of the old sand can be carried out.
Bei einer Vielzahl industrieller Verfahrensabläufe finden Wirbelschichtprozesse Anwendung, bei denen innerhalb eines Wirbelschichtofens aus Staub- bzw. fein- bis grobkörnigen Feststoffen und einem von unten eingeblasenen Anström- oder Wirbelgas eine Wirbelschicht ausgebildet wird, in welcher sowohl exotherme als auch endotherme Prozesse ablaufen. Als feinkörnige Feststoffe für die Vorgabe exothermer Reaktionen wird beispielsweise staubförmige Kohle in die Wirbelschicht eingebracht. Ein bekanntes Wirbelschichtenverfahren mit exothermer Reaktion, bei der jedoch kein Brennstoff in Form eines Festoffes für die Beheizung der Wirbelschicht eingesetzt wird, ist die Abröstung sulfidischer Erze, wie Pyrite, Bleiglanz oder Zinkblende innerhalb einer solchen Wirbelschicht. Bekannte Wirbelschichtprozesse mit endothermer Reaktions sind die Trocknung, Kalzinierung, Sinterung von staubförmigen bis körnigem Schüttgut.Fluidized bed processes are used in a large number of industrial processes in which a fluidized bed is formed within a fluidized bed furnace consisting of dust or fine to coarse-grained solids and an inflow or fluidized gas blown in from below, in which both exothermic and endothermic processes take place. Dusty coal, for example, is introduced into the fluidized bed as fine-grained solids for specifying exothermic reactions. A known fluidized bed process with an exothermic reaction, in which, however, no fuel in the form of a solid substance is used for heating the fluidized bed, is the roasting of sulfidic ores, such as pyrites, galena or zinc blende within such a fluidized bed. Known Fluidized bed processes with endothermic reaction are drying, calcining, sintering of dusty to granular bulk material.
Bei einem bekannten Verfahren zur Übertragung der in der Wirbelschicht eines Wirbelschichtofens anfallenden Wärme auf einen wärmeverbrauchenden Prozeß (DE-A-3232481) finden die exothermen und endothermen Prozesse innerhalb des Wirbelschichtofens getrennt voneinander statt. Hierfür wird innerhalb des Wirbelschichtofens im Bereich des Ofenbodens eine Wirbelschicht aus eingebrachtem Rieselstoff, wie Kohle, Müll, metallischen Stäuben oder dergleichen, für einen exothermen Verbrennungsvorgang ausgebildet. Der Ofenboden ist als Begasungsboden ausgebildet und besitzt mittig am Ende eines sich konisch verjüngenden Abschnittes eine Austragsöffnung für das Reaktionsprodukt. Rieselfähige Feststoffe, wie beispielsweise zu glühender harzhaltiger Altsand, aber auch Quarzsand oder Ton wird über ein als Wärmetauscher wirkendes Rohrsystem innerhalb des Wirbelschichtofens durch diesen hindurchgeleitet, um schließlich einem externen Sammelbehälter zugeführt zu werden, aus dem das Regenerat dann abgezogen werden kann. Diese bekannte Wirbelschichtofenanordnung ist besonders geeignet zum Aufbereiten oder Umwandeln von spezifisch schweren Stoffen, so z.B. für die Abröstung sulfidischer Erze. Gleichermaßen läßt sich das bekannte Verfahren bei entsprechend abgewandeltem Vorrichtungsaufbau zur Aufbereitung und Umwandelung spezifisch leichter Stoffe, so z.B. von harzhaltigen Bindemitteln oder Bindemittelresten, so wie sie Altsand anhaften, einsetzen.In a known method for transferring the heat accumulating in the fluidized bed of a fluidized bed furnace to a heat-consuming process (DE-A-3232481), the exothermic and endothermic processes within the fluidized bed furnace take place separately from one another. For this purpose, a fluidized bed of introduced trickle material, such as coal, garbage, metallic dusts or the like, is formed within the fluidized bed furnace in the region of the furnace floor for an exothermic combustion process. The furnace floor is designed as a gassing floor and has a discharge opening for the reaction product in the middle at the end of a conically tapering section. Free-flowing solids, such as old-fashioned resin-containing sand, but also quartz sand or clay, are passed through a pipe system acting as a heat exchanger inside the fluidized bed furnace, in order to be finally fed to an external collecting container from which the regrind can then be drawn off. This known fluidized bed furnace arrangement is particularly suitable for processing or converting specific heavy substances, e.g. for roasting sulfidic ores. Equally, the known method can be used with a correspondingly modified device structure for processing and converting specifically light substances, e.g. of resin-containing binders or binder residues, such as those adhering to used sand.
Unabhängig hiervon gehört es auch zum Stand der Technik kohlenstoffhaltige Materialien in Feuerungen mit stationärer Wirbelschicht zu verbrennen. Beim Betrieb der Feuerung wird Festmaterial aus der Wirbelschichtbrennkammer abgezogen, und zwar das aus der Asche und dem verwendeten Inertmaterial, wie beispielsweise Quarzsand bestehende Bettmaterial insgesamt. Dieses Material enthält Feinanteile, die der Wirbelschicht erneut zugeführt werden können. (DE-C-3107355).Regardless of this, it is also part of the prior art to burn carbon-containing materials in furnaces with a stationary fluidized bed. When operating the furnace, solid material is used withdrawn from the fluidized bed combustion chamber, namely the total bed material consisting of the ash and the inert material used, such as quartz sand. This material contains fine particles that can be added to the fluidized bed again. (DE-C-3107355).
Aus der GB-A-20 77 614 ist eine Vorrichtung bekannt, bei der das abgezogene Material einer Windsichtung unterzogen wird, wobei die Luft vor dem Zusammenführen mit dem Material von zumindest einem Teil des Festmaterials direkt erwärmt wird. Nach dem Zusammenführen mit dem abgezogenen Wirbelschichtmaterial nimmt die Luft von diesem Wärme auf, wonach sie mit dem Feinanteil des Schichtmaterials über ein zusätzlich durch Luft beaufschlagtes Förderrohr dem Brennraum der Wirbelschichtfeuerung wieder zugeführt wird.From GB-A-20 77 614 a device is known in which the material taken off is subjected to a wind sifting, the air being heated directly by at least part of the solid material before being brought together with the material. After merging with the withdrawn fluidized bed material, the air absorbs heat from it, after which it is fed back to the combustion chamber of the fluidized bed combustion system with the fine fraction of the layered material via a delivery pipe additionally subjected to air.
Von diesem Stand der Technik ausgehend liegt der vorliegenden Erfindung die Aufgabe zugrunde, ein Verfahren zur Inertisierung von Stäuben aus dem in Gießereien anfallendem Altsand zu schaffen, wie sie bei der Wiederaufbereitung durch das Trennen von Guß und Sand, das Sieben, Klassieren, Mischen und dergleichen mechanische Zerkleinerungsmaßnahmen entstehen, wobei gleichzeitig eine Minimierung der Energiebilanz ermöglicht werden soll.Starting from this prior art, the present invention has for its object to provide a method for inerting dusts from the old sand accumulating in foundries, such as in the reprocessing by separating cast iron and sand, sieving, classifying, mixing and the like Mechanical comminution measures arise, while at the same time minimizing the energy balance.
Die Lösung dieser Aufgabe wird erfindungsgemäß durch die im Kennzeichen des Anspruches 1 angegebenen Merkmale erreicht.This object is achieved according to the invention by the features specified in the characterizing part of claim 1.
Vorteilhafte Weiterbildungen und Ausgestaltungen dieser Verfahrensweise ergeben sich aus den Unteransprüchen.Advantageous further developments and refinements of this procedure result from the subclaims.
Dadurch, daß der bei der mechanischen Vorreinigung des Altsandes anfallende Staub mit einem erheblichen Anteil an organischen brennbaren Komponenten vor der thermischen Aufbereitung des Sandes abgetrennt wird, erhält man ein staubförmiges Material mit exothermer Energiebilanz. Die thermische Aufbereitung des Altsandes erfolgt nach der Abtrennung der anfallenden Staubkomponenten in einem Wirbelschichtofen, wobei der Altsand selbst die Wirbelschicht bildet. Die endotherme Aufbereitung des Altsandes geschieht in vorteilhafter Weise unter Ausnutzung des exothermen Prozesses der Verbrennung der organischen Staubkomponente innerhalb der Wirbelschicht. Die nicht brennbaren Komponenten des Staubes werden hierbei spätestens in der oberhalb der Wirbelschicht liegenden Nachverbrennungszone des Wirbelschichtofens inertisiert. Die dieser thermischen Aufbereitung vorgeschaltete mechanische Aufbereitung des Sandes ermöglicht für den erfindungsgemäßen Verfahrensablauf eine einfache Abtrennung der Stäube, etwa durch Absaugen und Abscheiden derselben in an sich bekannten Filteranlagen. Die Stäube bestehen im wesentlichen aus einer feinkörnigen Quarzfraktion, gegebenenfalls aus anderen anorganischen Stoffen, wie Tonpartikeln und aus einer nicht unerheblichen organischen Komponente aus staubförmigen Harzverbindungen. Derartige Staubgemische müßten, würden sie nicht in den Verfahrenskreislauf rückgeführt, Sonderdeponien zugeführt werden, das heißt, sie sind nur mit erheblichem Kostenaufwand zu entsorgen. Die erfindungsgemäße Inertisierung der Stäube macht das Verbringen derselben auf Sondermülldeponien überflüssig und verbessert darüberhinaus die Energiebilanz für den thermischen Aufbereitungsschritt des Altsandes erheblich.The fact that the mechanical pre-cleaning of the old sand Any dust that accumulates with a considerable proportion of organic combustible components is separated off before the sand is thermally processed. A dusty material with an exothermic energy balance is obtained. The used sand is thermally processed in a fluidized bed furnace after the dust components are separated off, the used sand itself forming the fluidized bed. The endothermic treatment of the used sand takes place advantageously using the exothermic process of the combustion of the organic dust component within the fluidized bed. The non-combustible components of the dust are rendered inert at the latest in the afterburning zone of the fluidized bed furnace above the fluidized bed. The mechanical treatment of the sand preceding this thermal treatment enables the dusts to be easily separated for the process sequence according to the invention, for example by suctioning and separating them in filter systems known per se. The dusts consist essentially of a fine-grained quartz fraction, optionally made of other inorganic substances such as clay particles and a not inconsiderable organic component made of dusty resin compounds. Such dust mixtures would have to be brought to special landfills if they were not returned to the process cycle, which means that they can only be disposed of at considerable expense. The inertization of the dusts according to the invention makes it unnecessary to place them in hazardous waste landfills and further improves the energy balance for the thermal treatment step of the old sand.
Das Einblasen der Stäube, so wie sie aus dem Sandkreislauf einer Gießerei gewonnen werden, erfolgt auf einfache Weise über den Boden des Wirbelschichtofens in die Wirbelschicht mittels über Wärmetauscher vorgewärmte Luft als Transportmittel, die als Anströmgas für die Wirbelschicht dient. Damit ist eine direkte Nutzung der brennbaren Bestandteile der Stäube zur Substitution der Primärenergie für die Beheizung des Wirbelschichtofens gegeben. Die Inertisierung des eingeblasenen Staubes, soweit es sich hierbei um unbrennbare Komponenten handelt, erfolgt somit praktisch gleichzeitig mit der thermischen Regenerierung des Gießerei-Altsandes. Die Abwärme des Wirbelschichtofens wird zur Vorwärmung der Einblasluft verwender.The dusts, such as those obtained from the sand cycle of a foundry, are blown in easily over the bottom of the fluidized bed furnace into the fluidized bed by means of heat exchangers preheated air as a means of transport, which serves as the inflow gas for the fluidized bed. This means that the combustible constituents of the dusts are used directly to substitute the primary energy for heating the fluidized bed furnace. The inertization of the blown-in dust, insofar as these are incombustible components, thus takes place practically simultaneously with the thermal regeneration of the old foundry sand. The waste heat from the fluidized bed furnace is used to preheat the blowing air.
Die beiliegende Zeichnung zeigt eine beispielsweise Ausführungsform einer Vorrichtung zur Durchführung des Verfahrens anhand derer nachfolgend die Erfindung näher erläutert werden soll.The accompanying drawing shows an example of an embodiment of a device for carrying out the method by means of which the invention is to be explained in more detail below.
Wie aus der Darstellung zu entnehmen, teilt sich der Innenraum des Wirbelschichtofens in die untere Wirbelschicht 4 und den oberen Nachverbrennungsraum 3, wobei in üblicher Weise die Wirbelschicht von der Anströmkammer für das Wirbelgas durch einen Siebboden oder dergleichen Lochplatte getrennt ist. Der aus der nicht dargestellten mechanischen Vorreinigung gewonnene Altsand 1, der zuvor von der Feinkorn-Komponente bzw. dort angefallenen Stäuben befreit worden ist, wird über eine Dosiervorrichtung 2 in der dargestellten Weise in den Wirbelschichtofen eingebracht. Der Altsand selbst gibt somit die Wirbelschicht 4 vor, dessen Verweilzeit innerhalb des Ofens so gesteuert wird, daß die an diesem noch anhaftenden brennbaren Binderreste innerhalb der Wirbelschicht 4 verbrannt werden, gegebenenfalls eine Kalzinierung erfolgt. Das bei dieser thermischen Regenerierung anfallende Regenerat 5 wird aus dem Ofen ausgetragen, um so der Neubildung von Gießereiformen zur Verfügung zu stehen.As can be seen from the illustration, the interior of the fluidized bed furnace is divided into the lower fluidized
Während der Anfahrphase des Wirbelschichtofens 3, 4 wird zunächst eine Sandschicht im Ofen bis zur Erreichung einer vorgegebenen Solltemperatur von im allgemeinen 500 °C bis 900 °C mittels Fremdenergie über ein Brenngas aufgeheizt, welches über ein Ventil 15 dosierbar in einen mittels Ventilator 14 beschleunigten Anstrom gegeben wird. Nach Erreichung der Solltemperatur innerhalb der Wirbelschicht 4 wird der aus dem Sandkreislauf gewonnene Staub über eine Staubaufgabe 6 und eine dosierende Zuführung 7 sowie ein Zwischensilo 9 von unten her in die Wirbelschicht 4 eingebracht. Als Transportmittel für den Staub durch eine Rohrleitung 10 dient hierbei Luft die mittels eines Wärmetauschers 11 vorgewärmt worden ist. Der Wärmetauscher 11 ist einerseits mit dem Auslaß der Nachverbrennungskammer 3 des Wirbelschichtofens verbunden und andererseits mit einem Geläse 8 über das Frischluft zugeführt wird, die den Wärmetauscher dann in der gewünschten vorgewärmten Form über die Rohrleitung 10 verläßt. Die abgekühlte Heißluft aus dem Wirbelschichtofen wird vom Wärmetauscher 11 einem Abscheider 12 zugeführt, der beispielsweise ein Zyklonabscheider oder eine geeignete Filtervorrichtung sein kann, mittels welcher die inertisierten bzw. kalzinierten Stäube vor dem Ausbringen der Abluft über einen Ventilator 13 in die Umwelt gereinigt werden.During the start-up phase of the fluidized
Vom Zwischensilo 9, wird der Staub mit seinen organischen brennbaren Bestandteilen über spezielle Lanzen oder dergleichen in die Rohrleitung 10 zur Bildung eines brennbaren Staubluftgemisches eindosiert. Je nach gegenwärtigem Heizwert des Staubes kann das Brenngas über das Ventil 15 gedrosselt bzw. ganz abgeschaltet werden, so daß die Beheizung der Wirbelschicht und die Aufrechterhaltung der Solltemperatur in derselben ausschließlich über den Staub erfolgt. Die hierfür erforderliche temperaturabhängige Dosierung kann über eine an sich bekannte Rückkopplungsschaltung gesteuert werden. In dem Abscheider 12 gewonnener inertisierter Staub wird über eine Zellenradschleuse 16 oder dergleichen Vorrichtung aus dem beschriebenen Rohrsystem ausgetragen und in einem Container 17 gesammtelt. Diesem Sammelgefäß kann beispielsweise ein Pelletisiermischer beigegeben sein oder er kann als solcher ausgebildet werden.From the
Der durch die Wirbelschicht 4 beim Hindurchführen verbrennende über die Leitung 10 zugeführte Staub ist in der Nachverbrennungskammer 3 einer Nachverbrennung unterworfen, so daß in jedem Fall sichergestellt wird, daß er den Wirbelschichtofen in vollständig inertisierter Form verläßt.The dust which is fed through the fluidized
Claims (5)
- Process for thermal regeneration of returned foundry sand (1) as well as treatment of dust formed during circulation of the sand using a fluidized-bed furnace with a fluidized bed (4) and a post-combustion chamber (3) as well as an exhaust-air heat exchanger (11), characterised in that heating of the fluidized bed (4), which has been raised to reaction temperature, is carried out at least to a substantial extent with the organic dust fraction obtained during the mechanical preparation of the waste sand, that non-combustible components of the dust fraction are at the latest in post-combustion of the fluidized-bed furnace purged by sintering and/or calcination processes, and that the regenerated material (5) and the purged dust given via the heat exchanger (11) are separately retrieved from the process.
- Process according to claim 1, characterised in that the dust is entered into the fluidized bed (4) at a temperature-dependent dosage.
- Process according to claim 1, characterised in that the dust is blown into the fluidized bed (4) by means of air which is preheated in the heat exchanger (11).
- Process according to claim 1, characterised in that preheating and ignition or combustion of the combustible dust portion is carried out in the fluidized bed (4), and post-combustion in the post-combustion chamber (3) located above the fluidized bed.
- Process according to claim 1, characterised in that starting up of the fluidized-bed furnace up to heating of the fluidized bed (4) to reaction temperature is carried out by means of a separate energy, for example fuel gas.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT91106468T ATE100742T1 (en) | 1990-05-10 | 1991-04-22 | PROCESSES FOR THERMAL REGENERATION OF WASTE SANDS FROM FOUNDRIES AND FOR THE TREATMENT OF DUSTS FROM THE SAND CYCLE. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4015031 | 1990-05-10 | ||
| DE4015031A DE4015031A1 (en) | 1990-05-10 | 1990-05-10 | METHOD FOR THE THERMAL REGENERATION OF OLD SANDS CONTAINING IN FOUNDRIES, AND FOR TREATING THE DUST RESULTING IN THE SAND CIRCUIT |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0456027A1 EP0456027A1 (en) | 1991-11-13 |
| EP0456027B1 true EP0456027B1 (en) | 1994-01-26 |
Family
ID=6406136
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP91106468A Expired - Lifetime EP0456027B1 (en) | 1990-05-10 | 1991-04-22 | Process for thermal regeneration of returned foundry sand and for treating dust formed during its circulation |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5289920A (en) |
| EP (1) | EP0456027B1 (en) |
| AT (1) | ATE100742T1 (en) |
| DE (2) | DE4015031A1 (en) |
Families Citing this family (33)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5251684A (en) * | 1991-12-06 | 1993-10-12 | Gmd Engineered Systems, Inc. | Method for controlling the oxidation and calcination of waste foundry sands |
| DE4212097A1 (en) * | 1992-04-10 | 1993-10-14 | Boenisch Dietmar | Method and device for regenerating foundry sand |
| DE4322947B4 (en) * | 1992-11-27 | 2006-02-02 | Förder- und Anlagentechnik GmbH | Arrangement for improving the processing properties of sands |
| FR2700972B1 (en) * | 1993-01-29 | 1995-04-21 | Neu Sechage Ind | Device for heat treatment of refractory particles. |
| CH688912A5 (en) * | 1993-06-17 | 1998-05-29 | Von Roll Umwelttechnik Ag | A process for the thermal treatment of solids which arise in the purification of flue gases. |
| DK171324B1 (en) * | 1994-06-29 | 1996-09-09 | Smidth & Co As F L | Installations for heat treatment of unitary material |
| US6000644A (en) * | 1997-07-31 | 1999-12-14 | General Kinematics Corporation | Method and apparatus for reclaiming foundry sand |
| US6691765B2 (en) | 2001-08-07 | 2004-02-17 | Noram Technology, Ltd. | Products for the manufacture of molds and cores used in metal casting and a method for their manufacture and recycle from crushed rock |
| US6631808B2 (en) | 2001-08-07 | 2003-10-14 | Particle And Coating Technologies, Inc. | Air classifier system for the separation of particles |
| DE10260741A1 (en) | 2002-12-23 | 2004-07-08 | Outokumpu Oyj | Process and plant for the heat treatment of fine-grained solids |
| DE10260738A1 (en) | 2002-12-23 | 2004-07-15 | Outokumpu Oyj | Process and plant for conveying fine-grained solids |
| DE10260734B4 (en) | 2002-12-23 | 2005-05-04 | Outokumpu Oyj | Process and plant for the production of carbon coke |
| DE10260731B4 (en) | 2002-12-23 | 2005-04-14 | Outokumpu Oyj | Process and plant for the heat treatment of iron oxide-containing solids |
| DE10260737B4 (en) | 2002-12-23 | 2005-06-30 | Outokumpu Oyj | Process and plant for the heat treatment of titanium-containing solids |
| DE10260739B3 (en) | 2002-12-23 | 2004-09-16 | Outokumpu Oy | Process and plant for producing metal oxide from metal compounds |
| DE10260736A1 (en) * | 2002-12-23 | 2004-09-02 | Outokumpu Oyj | Process and plant for the heat treatment of fine-grained solids |
| DE10260733B4 (en) | 2002-12-23 | 2010-08-12 | Outokumpu Oyj | Process and plant for the heat treatment of iron oxide-containing solids |
| US8523963B2 (en) * | 2004-10-12 | 2013-09-03 | Great River Energy | Apparatus for heat treatment of particulate materials |
| US8579999B2 (en) * | 2004-10-12 | 2013-11-12 | Great River Energy | Method of enhancing the quality of high-moisture materials using system heat sources |
| US7987613B2 (en) * | 2004-10-12 | 2011-08-02 | Great River Energy | Control system for particulate material drying apparatus and process |
| US7275644B2 (en) * | 2004-10-12 | 2007-10-02 | Great River Energy | Apparatus and method of separating and concentrating organic and/or non-organic material |
| BR112013032197A2 (en) * | 2011-06-23 | 2016-12-13 | S & B Ind Minerals North America Inc | method to improve casting quality |
| DE102013001801B4 (en) | 2013-02-01 | 2014-12-18 | Bernd Federhen | Method and device for the mechanical treatment of foundry sand |
| CN104096794A (en) * | 2013-04-08 | 2014-10-15 | 于彦奇 | Hot reclaimation device for clay sand |
| CN104759582A (en) * | 2015-03-18 | 2015-07-08 | 兰贤光 | Used resin regeneration crushing device |
| DE102015104340A1 (en) | 2015-03-23 | 2016-09-29 | Maschinenfabrik Gustav Eirich Gmbh & Co. Kg | Molding sand coolers |
| CN105170901B (en) * | 2015-10-26 | 2017-05-17 | 中车长江车辆有限公司 | Large-size cast steel wet type clay sand treatment system and sand treatment method |
| CN105458174A (en) * | 2016-01-21 | 2016-04-06 | 浙江卡博铜业有限公司 | Sand casting production line |
| WO2018157060A2 (en) | 2017-02-24 | 2018-08-30 | KB Foundry Services, LLC | Method and system for cleaning sand |
| DE102019130747A1 (en) * | 2019-11-14 | 2021-05-20 | WEBAC - Gesellschaft für Maschinenbau mbH | PLANT AND PROCESS FOR REGENERATING WASTE SAND, DEVICE FOR OPERATING SUCH A PLANT AND USING EXHAUST AIR |
| JP7567496B2 (en) * | 2021-01-21 | 2024-10-16 | トヨタ自動車株式会社 | Fluidized heating furnace and heating method |
| CN117564215B (en) * | 2024-01-15 | 2024-04-05 | 济南二机床集团有限公司 | A molding sand electric heating device and heating control method |
| US12390815B1 (en) | 2024-10-24 | 2025-08-19 | KB Foundry Services, LLC | Method and system for cleaning sand |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2252217A1 (en) * | 1972-10-25 | 1974-05-09 | Halbergerhuette Gmbh | Moulding sand reconditioning system - by heating in fluidized bed furn-ace and mechanical-pneumatic sepn. |
| US4144088A (en) * | 1977-01-19 | 1979-03-13 | Kenzler Engineering Company, Inc. | Process of reclaiming used foundry sand |
| JPS54140A (en) * | 1977-06-02 | 1979-01-05 | Toshiba Tungaloy Co Ltd | Wet type clutch and friction disc for use in wet type brake |
| GB2034679B (en) * | 1978-11-14 | 1982-05-19 | Coal Industry Patents Ltd | Heating slurries |
| CH640159A5 (en) * | 1979-06-06 | 1983-12-30 | Foundry Design Corp Europ | METHOD AND SYSTEM FOR MOLDING, WET SANDING AND CLEANING CASTING PIECES. |
| US4330502A (en) * | 1980-06-16 | 1982-05-18 | A. Ahlstrom Osakeyhtio | Fluidized bed reactor |
| EP0132493B1 (en) * | 1980-12-16 | 1988-06-15 | Cosworth Research And Development Limited | Apparatus for and method of reclaiming used foundry sand |
| DE3107355C2 (en) * | 1981-02-27 | 1990-11-15 | L. & C. Steinmüller GmbH, 5270 Gummersbach | Process for producing a fluidized bed with fluidized bed mass regulation |
| DE3232481A1 (en) * | 1981-09-04 | 1983-03-31 | Volkswagenwerk Ag, 3180 Wolfsburg | Process for the transfer of the heat, arising in the fluidised bed of a fluidised bed furnace, to a heat-utilising process, and fluidised bed furnace for carrying out the process |
| IT1155658B (en) * | 1982-03-23 | 1987-01-28 | Fata Ind Spa | SYSTEM AND METHOD FOR THE RECOVERY OF SANDS CONTAINED IN FOUNDRY SHAPES AND SOULS BY CALCINATION IN A FLUIDIZED BED OVEN |
| DE3636479A1 (en) * | 1986-10-27 | 1988-05-05 | Foerder & Anlagentechnik Gmbh | METHOD AND ARRANGEMENT FOR THE THERMO-MECHANICAL REGENERATION OF SCHUETTGUETE, ESPECIALLY OF FOUNDRY OLD SAND |
| DE3724541A1 (en) * | 1987-07-24 | 1989-02-02 | Applied Ind Materials | METHOD AND SYSTEM FOR THE PRODUCTION OF RAW MATERIAL BRIQUETTES FOR THE PRODUCTION OF SILICON OR SILICON CARBIDE OR FERROSILICIUM |
| DE3825361A1 (en) * | 1988-07-26 | 1990-02-08 | Hermann Jacob | Method and installation for regenerating mixtures of used foundry sand |
| DE3903604C1 (en) * | 1989-02-08 | 1990-03-29 | Siempelkamp Giesserei Gmbh & Co, 4150 Krefeld, De | Process for regenerating moulding sand |
| US5069171A (en) * | 1990-06-12 | 1991-12-03 | Foster Wheeler Agency Corporation | Fluidized bed combustion system and method having an integral recycle heat exchanger with a transverse outlet chamber |
-
1990
- 1990-05-10 DE DE4015031A patent/DE4015031A1/en active Granted
-
1991
- 1991-04-22 AT AT91106468T patent/ATE100742T1/en not_active IP Right Cessation
- 1991-04-22 EP EP91106468A patent/EP0456027B1/en not_active Expired - Lifetime
- 1991-04-22 DE DE91106468T patent/DE59100931D1/en not_active Expired - Fee Related
- 1991-05-10 US US07/698,402 patent/US5289920A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| ATE100742T1 (en) | 1994-02-15 |
| US5289920A (en) | 1994-03-01 |
| DE4015031A1 (en) | 1991-11-14 |
| DE59100931D1 (en) | 1994-03-10 |
| EP0456027A1 (en) | 1991-11-13 |
| DE4015031C2 (en) | 1993-06-17 |
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