EP0579214B1 - Process for milling crude lignite - Google Patents
Process for milling crude lignite Download PDFInfo
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- EP0579214B1 EP0579214B1 EP93111318A EP93111318A EP0579214B1 EP 0579214 B1 EP0579214 B1 EP 0579214B1 EP 93111318 A EP93111318 A EP 93111318A EP 93111318 A EP93111318 A EP 93111318A EP 0579214 B1 EP0579214 B1 EP 0579214B1
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- Prior art keywords
- lignite
- air
- process according
- roller mill
- crushing
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10F—DRYING OR WORKING-UP OF PEAT
- C10F7/00—Working-up peat
- C10F7/02—Disintegrating peat
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C15/00—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C15/00—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs
- B02C2015/002—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs combined with a classifier
Definitions
- the invention relates to a method for grinding raw lignite to fine coal.
- the raw lignite For the grinding of usually moist raw lignite to fine coal, the raw lignite has previously been passed through dryers in which, for example, indirect steam heating of the coal is carried out and in this way the moisture is largely removed from the coal.
- the raw lignite usually leaves these dryers at a temperature of 70 - 85 ° C.
- the dried raw lignite Due to this initial temperature after drying the raw lignite from 70 - 85 ° C, the dried raw lignite is cooled down to a temperature range of about 40 ° C. This happens e.g. in air-cooled trough chain conveyors.
- the raw lignite that has been dried and cooled in this way has so far been produced in pure continuous mills with grinding media are designed in particular as rods or balls, crushed and ground.
- these continuous mills designed, for example, as vibratory mills or agitator ball mills
- the raw lignite is crushed mainly between the grinding media and the grinding chamber wall.
- the friction between the grinding media with one another and between the grinding media and the wall of the grinding chamber generates heat, which can result in a sharp temperature increase of, for example, 20 ° C. with dried raw lignite.
- the previously cooled raw lignite therefore again reaches the permissible temperature limit of around 60 ° C.
- the continuous mills used had a capacity limit of approximately 10 t / h of raw lignite throughput.
- a capacity limit of approximately 10 t / h of raw lignite throughput In order to achieve a throughput of raw lignite of around 60 t / h, six to ten such continuous mills had to be used, depending on the fineness of the product, which in the previous stages required, for example, four dryers for the raw lignite with subsequent four air-cooled trough chain conveyors.
- the object of the invention is therefore to design a generic method with comparable throughput performance, and to achieve qualitative improvements in the grinding process and in the conveyance of the ground material if possible.
- An essential core idea of the invention is to combine the grinding process with the cooling process below the critical limit temperature of 60 ° C., an airflow roller mill being particularly suitable for this.
- Such an airflow roller mill for example of the LOESCHE type, has a rotating grinding table or a grinding bowl and thereon friction rollers driven by the material to be ground or provided with its own drive.
- a circumferential blade ring is arranged around the edge of the grinding bowl, through which the air flow is sucked or blown into the grinding chamber at high speed and with a swirl component.
- the material that is thrown and also comminuted by the grinding bowl is in this case caught in the approximately hollow cylindrical outer annular space by the air flow and guided in a rotating fluidized bed to the classifier arranged above the grinding chamber.
- the invention now goes the way of sucking in or blowing in cold gas, in particular cold air or ambient air, via the blade ring into the grinding chamber and, through an intimate purging of the raw lignite particles, which have a temperature of about 80 ° C., for example, a cooling of these particles during the rotation of the fluidized bed of the dust-air mixture to reach the classifier.
- the flow rate and the throughput of the cold air can also depend on the task of the raw lignite to be ground are regulated in such a way that the critical limit temperature of 60 ° C. for the raw lignite particles leaving the airflow roller mill and the classifier is reached or fallen below.
- the preferred type of airflow roller mill for this method has a minimum distance between the grinding elements, that is to say the grinding bowl and the grinding rollers, so that direct metallic contact, which leads to high frictional heat, is avoided.
- the subsequent screening of the raw lignite particles fed to the classifier in an ascending rotating fluidized bed therefore guarantees a high degree of constancy of the fine grain belt, regardless of part-load or full-load operation.
- the cold gas or cold air that flows in can be used optimally at the same time as a conveying medium for the forwarding of the ground and sifted goods in intermediate silos or to consumers.
- the airflow roller mill is operated in the negative pressure mode, as a result of which the cooling processes and the pneumatic conveying within the roller mill are more efficient and energy-saving.
- the corresponding fans are provided behind the airflow roller mill and in particular behind the dust separators which are connected downstream of the classifier. This suction effect of the fans avoids any temperature increase in the interior of the airflow roller mill, which maintains the cooling effect in the roller mill.
- the predestined area of application of the process is the grinding of raw lignite.
- other types of raw coal can also be ground extremely economically in the manner described above using the method.
- FIG. 1 An airflow roller mill 1 is shown in FIG.
- This roller mill 1 has a driven, rotating grinding bowl 2 and grinding rollers 3 which roll on it in a frictionally locking manner or are driven separately.
- a classifier 4 is provided in the housing of the airflow roller mill 1.
- the usually moist raw lignite is in the process first of all via dryers 11, e.g. Tube dryers with indirect steam heating can be guided and dried in them.
- the raw lignite comes from these dryers 11 at a temperature of about 70-85 ° C. to a conveyor 12 and then to a weighing belt 13 for the metered feeding of the dried raw lignite.
- the raw lignite is introduced into the airflow roller mill 1 via a cellular wheel sluice 14 and a feed 7.
- a cold gas 18, in particular cold air from the atmosphere, is fed to the roller mill 1 in the lower region, which then flows into the grinding chamber 5 via a blade ring 17.
- FIG. 2 shows the grinding chamber 5 of the roller mill 1 in a larger, schematic partial view.
- the cold air 18 is blown into the grinding chamber 5 with a swirling movement in the edge region of the grinding bowl 2, which is set in rotation by a drive 16, by means of a blade ring 17.
- an intimate purging takes place between the cold air 18 and the ground raw carbon particles 21.
- the formation of a rotating and rising fluidized bed 24 of cold air 18 and ground raw coal particles 21 leads to a cooling of the raw brown coal particles below the critical limit of 60 ° C.
- the raw lignite 23 is placed approximately in the middle of the rotating grinding bowl 2 and, by centrifugal force, reaches radially outwards, where it is crushed and ground under the pressure of the grinding rollers 3.
- the carbon particles 21 thrown off in the direction of the arrow 25 are then effectively cooled in the rotating fluidized bed 24 by contact with the cold air 18. This cooling process can be regulated by the flow rate of the cold air and its temperature.
- the classifier 4 also makes it possible that the fine material leaving the classifier 4 via the outlet 9 can be set to a high constancy of a desired dust particle band, regardless of part-load or full-load operation.
- the cold air 18 used can advantageously be used simultaneously for the pneumatic conveying of the fine material to intermediate silos or to consumers.
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- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Crushing And Grinding (AREA)
- Disintegrating Or Milling (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
Description
Die Erfindung betrifft ein Verfahren zur Mahlung von Rohbraunkohle zu Feinkohle.The invention relates to a method for grinding raw lignite to fine coal.
Zur Vermahlung von üblicherweise feuchter Rohbraunkohle zu Feinkohle wird bisher zunächst die Rohbraunkohle durch Trockner geleitet, in denen beispielsweise eine indirekte Dampfbeheizung der Kohle durchgeführt wird und auf diese Weise der Kohle die Feuchtigkeit weitgehend entzogen wird. Die Rohbraunkohle verläßt diese Trockner üblicherweise mit einer Temperatur von 70 - 85 °C.For the grinding of usually moist raw lignite to fine coal, the raw lignite has previously been passed through dryers in which, for example, indirect steam heating of the coal is carried out and in this way the moisture is largely removed from the coal. The raw lignite usually leaves these dryers at a temperature of 70 - 85 ° C.
Da diese relativ hohe Temperatur von 70 - 85 °C im Hinblick auf ein Entzünden oder auf eine Explosion des Kohlestaubgemisches als äußerst problematisch angesehen werden muß, hat man für Braunkohlenstaub als höchstzulässige Temperatur 60 °C festgelegt, um die vorgenannten Gefahrenmomente ausschließen zu können.Since this relatively high temperature of 70 - 85 ° C must be regarded as extremely problematic with regard to ignition or an explosion of the coal dust mixture, the maximum permissible temperature for lignite dust has been set at 60 ° C in order to be able to exclude the aforementioned dangerous moments.
Aufgrund dieser Ausgangstemperatur nach dem Trocknen der Rohbraunkohle von 70 - 85 °C wird die getrocknete Rohbraunkohle auf einen Temperaturbereich von etwa 40 °C herabgekühlt. Dies geschieht z.B. in luftgekühlten Trogkettenförderern.Due to this initial temperature after drying the raw lignite from 70 - 85 ° C, the dried raw lignite is cooled down to a temperature range of about 40 ° C. This happens e.g. in air-cooled trough chain conveyors.
Die derart getrocknete und abgekühlte Rohbraunkohle wird bisher in reinen Durchlaufmühlen mit Mahlkörpern, die insbesondere als Stangen oder Kugeln ausgelegt sind, zerkleinert und zermahlen. Bei diesen z.B. als Schwingmühlen oder Rührwerkskugelmühlen konzipierten Durchlaufmühlen erfolgt die Zerkleinerung der Rohbraunkohle hauptsächlich zwischen den Mahlkörpern und der Mahlraumwand.
In diesen Durchlaufmühlen wird durch die Reibung zwischen den Mahlkörpern untereinander sowie zwischen den Mahlkörpern und der Mahlraumwand Wärme erzeugt, die sich in einer starken Temperaturerhöhung von z.B. 20 °C bei getrockneter Rohbraunkohle auswirken kann. Die vorausgehend abgekühlte Rohbraunkohle erreicht daher wiederum den zulässigen Grenztemperaturbereich von etwa 60 °C.The raw lignite that has been dried and cooled in this way has so far been produced in pure continuous mills with grinding media are designed in particular as rods or balls, crushed and ground. In these continuous mills designed, for example, as vibratory mills or agitator ball mills, the raw lignite is crushed mainly between the grinding media and the grinding chamber wall.
In these continuous mills, the friction between the grinding media with one another and between the grinding media and the wall of the grinding chamber generates heat, which can result in a sharp temperature increase of, for example, 20 ° C. with dried raw lignite. The previously cooled raw lignite therefore again reaches the permissible temperature limit of around 60 ° C.
Bei diesem bisher praktizierten Verfahren hat sich als besonders nachteilig herausgestellt, daß die eingesetzten Durchlaufmühlen eine Kapazitätsgrenze von ca. 10 t/h an Rohbraunkohledurchsatz besaßen.
Um daher einen Durchsatz an Rohbraunkohle von etwa 60 t/h zu erreichen, mußten bisher je nach Produktfeinheit sechs bis zehn derartige Durchlaufmühlen eingesetzt werden, die in den vorausgehenden Stufen z.B. vier Trockner für die Rohbraunkohle mit nachfolgenden vier luftgekühlten Trogkettenförderern erforderlich machten.In this previously practiced process, it has been found to be particularly disadvantageous that the continuous mills used had a capacity limit of approximately 10 t / h of raw lignite throughput.
In order to achieve a throughput of raw lignite of around 60 t / h, six to ten such continuous mills had to be used, depending on the fineness of the product, which in the previous stages required, for example, four dryers for the raw lignite with subsequent four air-cooled trough chain conveyors.
Es zeigte sich daher, daß die höhere Durchsatzkapazität eine Vielzahl von derartigen Einheiten mit entsprechend höherer Anzahl von Antrieben, Zu- und Abtransportgeräten, Fundamenten, Gebäuden mit Schallisolierung und einem höheren Überwachungs- und Regelaufwand erforderlich machte.It was therefore shown that the higher throughput capacity required a large number of such units with a correspondingly higher number of drives, supply and removal devices, foundations, buildings with sound insulation and a higher monitoring and control expenditure.
Für dieses bisher praktizierte Verfahren war es jedoch erforderlich, die Temperatur der Rohbraunkohle vor den Mühlen auf maximal 40 °C zu begrenzen, was nur durch zusätzliche Kühlaggregate mit entsprechend hohem Investitionsaufwand, Platzbedarf und weiterhin damit verbundenem Transport-, Regelungs- und Wartungsaufwand verbunden war.For this previously practiced process, however, it was necessary to limit the temperature of the raw lignite in front of the mills to a maximum of 40 ° C, which was only associated with correspondingly high capital expenditure, space requirements and the associated transport, control and maintenance expenditure due to additional cooling units.
Unter Berücksichtigung dieser Gesichtspunkte liegt daher der Erfindung die Aufgabe zugrunde, ein gattungsgemäßes Verfahren bei vergleichbarer Druchsatzleistung investitionsgünstiger zu konzipieren und dabei nach Möglichkeit auch qualitative Verbesserungen im Mahlprozeß und bei der Förderung des gemahlenen Gutes zu erreichen.Taking these aspects into account, the object of the invention is therefore to design a generic method with comparable throughput performance, and to achieve qualitative improvements in the grinding process and in the conveyance of the ground material if possible.
Diese Aufgabe wird erfindungsgemäß durch die Merkmale des Anspruchs 1 gelöst.This object is achieved by the features of claim 1.
Ein wesentlicher Kerngedanke der Erfindung ist hierbei, den Mahlprozeß mit dem Abkühlprozeß unter die kritische Grenztemperatur von 60 °C zu verbinden, wobei hierfür insbesondere eine Luftstrom-Wälzmühle geeignet ist.
Eine derartige Luftstrom-Wälzmühle, z.B. vom LOESCHE-Typ weist einen rotierenden Mahlteller bzw. eine Mahlschüssel und darauf reibschlüssig über das zu mahlende Gut angetriebene oder mit eigenem Antrieb versehene Mahlwalzen auf. Um den Mahlschüsselrand ist ein umlaufender Schaufelkranz angeordnet, durch den die Luftströmung mit hoher Geschwindigkeit und einer Drallkomponente in den Mahlraum eingesaugt bzw. eingeblasen wird. Das von der Mahlschüssel abgeschleuderte und auch zerkleinerte Gut wird hierbei im etwa hohlzylindrischen äußeren Ringraum von der Luftströmung erfaßt und in einer rotierenden Wirbelschicht zu dem oberhalb des Mahlraumes angeordneten Sichter geführt.An essential core idea of the invention is to combine the grinding process with the cooling process below the critical limit temperature of 60 ° C., an airflow roller mill being particularly suitable for this.
Such an airflow roller mill, for example of the LOESCHE type, has a rotating grinding table or a grinding bowl and thereon friction rollers driven by the material to be ground or provided with its own drive. A circumferential blade ring is arranged around the edge of the grinding bowl, through which the air flow is sucked or blown into the grinding chamber at high speed and with a swirl component. The material that is thrown and also comminuted by the grinding bowl is in this case caught in the approximately hollow cylindrical outer annular space by the air flow and guided in a rotating fluidized bed to the classifier arranged above the grinding chamber.
Die Erfindung geht nunmehr den Weg, Kaltgas, insbesondere Kaltluft oder Umgebungsluft, über den Schaufelkranz in den Mahlraum einzusaugen bzw. einzublasen und durch eine innige Umspülung der z.B. eine Temperatur von etwa 80 °C aufweisenden Rohbraunkohlepartikel, eine Abkühlung dieser Partikel während der Rotation der Wirbelschicht des Staub-Luft-Gemisches nach oben zum Sichter zu erreichen. Hierbei kann die Strömungsgeschwindigkeit und der Durchsatz der Kaltluft auch in Abhänigkeit von der Aufgabe der zu mahlenden Rohbraunkohle so geregelt werden, daß auf alle Fälle die kritische Grenztemperatur von 60 °C bei den die Luftstrom-Wälzmühle und den Sichter verlassenden Rohbraunkohlepartikeln erreicht oder unterschritten wird.The invention now goes the way of sucking in or blowing in cold gas, in particular cold air or ambient air, via the blade ring into the grinding chamber and, through an intimate purging of the raw lignite particles, which have a temperature of about 80 ° C., for example, a cooling of these particles during the rotation of the fluidized bed of the dust-air mixture to reach the classifier. The flow rate and the throughput of the cold air can also depend on the task of the raw lignite to be ground are regulated in such a way that the critical limit temperature of 60 ° C. for the raw lignite particles leaving the airflow roller mill and the classifier is reached or fallen below.
Der bevorzugte Luftstrom-Wälzmühlentyp für dieses Verfahren weist zwischen den Mahlkörpern, also der Mahlschüssel und den Mahlwalzen einen Mindestabstand auf, so daß ein direkter metallischer Kontakt, der zu hoher Reibungswärme führt, vermieden wird.The preferred type of airflow roller mill for this method has a minimum distance between the grinding elements, that is to say the grinding bowl and the grinding rollers, so that direct metallic contact, which leads to high frictional heat, is avoided.
Die nachfolgende Sichtung der in einer aufsteigenden rotierenden Wirbelschicht dem Sichter zugeführten Rohbraunkohlepartikel gewährleistet daher unabhängig von Teillast- oder Vollastbetrieb eine hohe Konstanz des Feinkorn-Bandes, worunter ein Sichtgut mit weitestgehend unveränderlicher Kornverteilungscharakteristik zu verstehen ist.The subsequent screening of the raw lignite particles fed to the classifier in an ascending rotating fluidized bed therefore guarantees a high degree of constancy of the fine grain belt, regardless of part-load or full-load operation.
Zudem jedoch kann durch das eingeströmte Kaltgas bzw. die Kaltluft diese gleichzeitig als Fördermedium zur Weiterleitung des gemahlenen und gesichteten Gutes in Zwischensilos oder zu Verbrauchern optimal eingesetzt werden.In addition, however, the cold gas or cold air that flows in can be used optimally at the same time as a conveying medium for the forwarding of the ground and sifted goods in intermediate silos or to consumers.
Die verfahrensmäßige Integration einer Luftstrom-Wälzmühle für die Vermahlung von Rohbraunkohle aber auch anderer Rohkohle ermöglicht besonders hohe Durchsatzleistungen, da diese Luftstrom-Wälzmühlen in größeren Einheiten gebaut werden können und z.B. sechs bis zehn Schwingmühlen bekannter Art ersetzen können.
Zudem wird bei diesen Wälzmühlen die Reibungswärme durch den direkten Kontakt zwischen den Mahlteilen vermieden. Dies kann beispielsweise durch mechanische Abstandshalter für die Mahlwalzen gegenüber der Mahlschüssel realisiert werden.The procedural integration of an airflow roller mill for the grinding of raw lignite as well as other raw coal enables particularly high throughput rates, since these airflow roller mills can be built in larger units and can, for example, replace six to ten vibratory mills of a known type.
In addition, with these roller mills the frictional heat is avoided by the direct contact between the grinding parts. This can be achieved, for example, by mechanical spacers for the grinding rollers compared to the grinding bowl.
Da der Kaltluftstrom bei einer derartigen Luftstrom-Wälzmühle aus der Atmosphäre angesaugt werden kann, erübrigt sich ein Herabkühlen der getrockneten Rohbraunkohle aus dem Temperaturbereich von 70 - 85 °C auf Bereiche bei etwa 40 °C, so daß erhebliche Investitionen an Kühlaggregaten eingespart werden können.Since the cold air flow can be sucked from the atmosphere in such an air flow roller mill, this is not necessary the dried raw lignite cools down from the temperature range of 70-85 ° C. to ranges around 40 ° C., so that considerable investments in cooling units can be saved.
Hinzu tritt, daß der apparative Gesamtaufwand beim Einsatz einer Lufstrom-Wälzmühle anstelle von sechs bis zehn Schwingmühlen sowie der entsprechende Folgeaufwand erheblich reduziert werden kann.In addition, the overall expenditure on equipment when using an airflow roller mill instead of six to ten vibratory mills and the corresponding subsequent expenditure can be considerably reduced.
Ein weiterer Vorteil stellt sich dadurch ein, daß die Luftstrom-Wälzmühle im Unterdruckbetrieb gefahren wird, wodurch die Abkühlungsvorgänge und die pneumatische Förderung innerhalb der Wälzmühle effizienter und energiesparender sind. Für den vorzugsweise gewählten Unterdruckbetrieb, der auch als Saugbetrieb bezeichnet werden kann, werden die entsprechenden Ventilatoren hinter der Luftstrom-Wälzmühle und insbesondere hinter den Staubabscheidern, die dem Sichter nachgeschaltet sind, vorgesehen. Durch diese Saugwirkung der Ventilatoren vermeidet man jegliche Temperaturerhöhung im Innenraum der Luftstrom-Wälzmühle, wodurch die Kühlwirkung in der Wälzmühle aufrechterhalten wird.Another advantage arises from the fact that the airflow roller mill is operated in the negative pressure mode, as a result of which the cooling processes and the pneumatic conveying within the roller mill are more efficient and energy-saving. For the preferably selected vacuum operation, which can also be referred to as suction operation, the corresponding fans are provided behind the airflow roller mill and in particular behind the dust separators which are connected downstream of the classifier. This suction effect of the fans avoids any temperature increase in the interior of the airflow roller mill, which maintains the cooling effect in the roller mill.
Zwar ist das prädestinierte Einsatzgebiet des Verfahrens die Mahlung von Rohbraunkohle. Andere Rohkohlearten lassen sich jedoch ebenfalls in vorbeschriebener Weise mittels des Verfahrens äußerst wirtschaftlich mahlen.The predestined area of application of the process is the grinding of raw lignite. However, other types of raw coal can also be ground extremely economically in the manner described above using the method.
Die Erfindung wird nachstehend anhand eines Beispieles weiter erläutert. Es zeigen:
- Fig. 1
- eine schematische Darstellung des Verfahrens mit den wesentlichen Aggregaten und
- Fig. 2
- eine vergrößerte Darstellung eines Ausschnittes durch den Mahlbereich der Luftstrom-Wälzmühle nach Fig. 1 mit den wesentlichen Strömungsverhältnissen.
- Fig. 1
- a schematic representation of the process with the essential units and
- Fig. 2
- an enlarged view of a section through the grinding area of the airflow roller mill of FIG. 1 with the essential flow conditions.
In Figur 1 ist eine Luftstrom-Wälzmühle 1 dargestellt. Diese Wälzmühle 1 hat eine angetriebene, rotierende Mahlschüssel 2 und auf dieser reibschlüssig abrollende oder gesondert angetriebene Mahlwalzen 3. Oberhalb des Mahlraumes 5 ist ein Sichter 4 integriert im Gehäuse der Luftstrom-Wälzmühle 1 vorgesehen.An airflow roller mill 1 is shown in FIG. This roller mill 1 has a driven, rotating grinding bowl 2 and grinding rollers 3 which roll on it in a frictionally locking manner or are driven separately. Above the grinding chamber 5, a classifier 4 is provided in the housing of the airflow roller mill 1.
Die üblicherweise feuchte Rohbraunkohle wird im Verfahren zunächst über Trockner 11, die z.B. Röhrentrockner mit indirekter Dampfbeheizung sein können, geführt und darin getrocknet. Die Rohbraunkohle gelangt mit einer Temperatur von etwa 70 - 85 °C aus diesen Trocknern 11 auf einen Förderer 12 und anschließend auf ein Wiegeband 13 zur dosierten Aufgabe der getrockneten Rohbraunkohle. Über eine Zellradschleuse 14 und eine Zuführung 7 wird die Rohbraunkohle in die Luftstrom-Wälzmühle 1 eingeführt.The usually moist raw lignite is in the process first of all via dryers 11, e.g. Tube dryers with indirect steam heating can be guided and dried in them. The raw lignite comes from these dryers 11 at a temperature of about 70-85 ° C. to a conveyor 12 and then to a weighing
Der Wälzmühle 1 wird im unteren Bereich ein Kaltgas 18, insbesondere Kaltluft aus der Atmosphäre, zugeleitet, welches anschließend über einen Schaufelkranz 17 in den Mahlraum 5 einströmt.A
In Fig. 2 ist in einer größeren, schematischen Teilansicht der Mahlraum 5 der Wälzmühle 1 dargestellt. Die Kaltluft 18 wird hierbei im Randbereich der Mahlschüssel 2, die über einen Antrieb 16 in Rotation versetzt wird, über einen Schaufelkranz 17 mit einer Drallbewegung aufwärts in den Mahlraum 5 eingeblasen. In einem äußeren, hohlzylindrischen Ringraum 22 erfolgt hierbei zwischen der Kaltluft 18 und den gemahlenen Rohkohlepartikeln 21 eine innige Umspülung. Die Bildung einer rotierenden und aufsteigenden Wirbelschicht 24 von Kaltluft 18 und gemahlenen Rohkohlepartikeln 21 führt zu einer Abkühlung der Rohbraunkohlepartikel unter den kritischen Grenzwert von 60 °C.2 shows the grinding chamber 5 of the roller mill 1 in a larger, schematic partial view. In this case, the
Die Rohbraunkohle 23 wird etwa mittig auf die rotierende Mahlschüssel 2 aufgegeben und gelangt durch Fliehkraft radial nach außen, wo sie unter dem Druck der Mahlwalzen 3 zerkleinert und zermahlen wird. Die in Richtung des Pfeils 25 abgeschleuderten Kohlepartikel 21 werden dann in der rotierenden Wirbelschicht 24 durch Berührung mit der Kaltluft 18 effektiv abgekühlt. Dieser Kühlungsprozeß kann durch die Strömungsgeschwindigkeit der Kaltluft und deren Temperatur geregelt werden.The
Die in Pfeilrichtung 20 aufsteigende rotierende Wirbelschicht 24, die zwischen dem Gehäuse 15 und dem Rand des Mahltellers 2 entsteht, wird durch die Schaufelneigung des Schaufelkranzes 17 und die dadurch in einen Drall versetzte Wirbelströmung 19 erzeugt.The rotating
In dieser Wirbelschicht geben die allseits von Kaltluft umströmten Kohlepartikel ihre Wärme an die Kaltluft ab, bis am Auslaß 9 des Kohlenstaubes aus dem in der Wälzmühle 1 integrierten Sichter 4 eine Temperatur unter 60 °C erreicht wird (Fig. 1).In this fluidized bed, the carbon particles flowed around on all sides by cold air give off their heat to the cold air until a temperature below 60 ° C. is reached at the outlet 9 of the coal dust from the classifier 4 integrated in the roller mill 1 (FIG. 1).
Der Sichter 4 ermöglicht es zudem, daß unabhängig von Teillast- oder Vollastbetrieb das den Sichter 4 über den Auslaß 9 verlassende Feingut auf eine hohe Konstanz eines gewünschten Staubkorn-Bandes eingestellt werden kann.The classifier 4 also makes it possible that the fine material leaving the classifier 4 via the outlet 9 can be set to a high constancy of a desired dust particle band, regardless of part-load or full-load operation.
Die eingesetzte Kaltluft 18 kann vorteilhafterweise gleichzeitig für die pneumatische Weiterförderung des Feingutes zu Zwischensilos oder zu Verbrauchern genutzt zu werden.The
Claims (9)
- Process for crushing raw lignite to fine coal, in which previously the raw lignite is dried and subsequently the dried raw lignite is crushed
characterized in
that the raw lignite (23) from the drying with an exit temperature of approximately 70 to 85°C is supplied to an air-swept roller mill (1) and is crushed therein,
that the air-swept roller mill (1) is passed through by a cold gas (18) having a lower temperature than the exit temperature of approximately 70 - 85°C of the raw lignite (23), particularly cold air and/or ambient air, and
that hereby at least the crushed lignite particles (21) in exchange with the cold gas (18), particularly cold air and/or ambient air, are cooled to a temperature below 60°C. - Process according to claim 1,
characterized in
that in an outer annulus (22) of the air-swept roller mill (1), which comprises a crushing pan (2), crushing rollers (3) and a blade ring (17), is formed a rotary fluidized bed (19) of cold gas (18) and lignite particles (21) for cooling the lignite particles (21) to below 60°C. - Process according to one of the claims 1 or 2,
characterized in
that the crushing of the raw lignite (23) is carried out whilst maintaining a minimum spacing between the crushing pan (2) and crushing rollers (3). - Process according to anyone of the claims 1 to 3,
characterized in
that the cold gas (18) and the lignite particles (21) form a gas-dust mixture, which is supplied to a classification process, particularly in an classifier (4) integrated with the air-swept roller mill (1). - Process according to one of the claims 1 to 4,
characterized in
that the fluidized bed (19) is formed by blowing a spiral flow of cold gas (18) through the blade ring (17) surrounding the crushing pan (2). - Process according to one of the claims 1 to 5,
characterized in
that the cooling of the lignite particles (21) is regulated by the inflow speed, particularly in the range 40 to 80 m/s, and/or by the temperature of the cold gas (18.) - Process according to one of the claims 1 to 6,
characterized in
that there is a pneumatic conveying of the crushed and cooled lignite particles. - Process according to one of the claims 1 to 7,
characterized in
that independently of the full or partial load operation, the classification of the lignite particles is set to a desired constancy of a particle band. - Process according to one of the claims 1 to 8,
characterized in
that the air-swept roller mill (1) is operated in the vacuum range.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4223151A DE4223151C2 (en) | 1992-07-14 | 1992-07-14 | Process for grinding raw lignite |
| DE4223151 | 1992-07-14 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0579214A1 EP0579214A1 (en) | 1994-01-19 |
| EP0579214B1 true EP0579214B1 (en) | 1997-06-11 |
| EP0579214B2 EP0579214B2 (en) | 2004-08-25 |
Family
ID=6463183
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP93111318A Expired - Lifetime EP0579214B2 (en) | 1992-07-14 | 1993-07-14 | Process for milling crude lignite |
Country Status (11)
| Country | Link |
|---|---|
| US (1) | US5353997A (en) |
| EP (1) | EP0579214B2 (en) |
| CN (1) | CN1033218C (en) |
| AU (1) | AU663790B2 (en) |
| CA (1) | CA2100490A1 (en) |
| CZ (1) | CZ283804B6 (en) |
| DE (2) | DE4223151C2 (en) |
| ES (1) | ES2102557T5 (en) |
| GR (1) | GR3024117T3 (en) |
| RU (1) | RU2109569C1 (en) |
| SK (1) | SK279856B6 (en) |
Families Citing this family (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7964128B2 (en) | 2001-12-19 | 2011-06-21 | Pirelli Pneumatici S.P.A. | Process and apparatus for continuously producing an elastomeric composition |
| DE10319786A1 (en) * | 2002-05-04 | 2003-11-27 | Christoph Muther | Industrial and domestic mixed and composite solid waste is separated for recycling by shock-wave treatment of comminuted solids in liquid suspension |
| AUPS236102A0 (en) * | 2002-05-16 | 2002-06-13 | Aimbridge Pty Ltd | Grinder |
| EP1521668B1 (en) | 2002-07-11 | 2010-04-14 | Pirelli Tyre S.p.A. | Process and apparatus for continuously producing an elatomeric composition |
| DE102005040519B4 (en) * | 2005-08-26 | 2009-12-31 | Loesche Gmbh | Method and device for grinding hot and humid raw material |
| CZ301641B6 (en) * | 2007-12-17 | 2010-05-12 | Vysoká škola bánská - TU OSTRAVA | Ring-shaped drop through flap |
| CN101285587B (en) * | 2008-03-28 | 2010-10-13 | 中国神华能源股份有限公司 | Low metamorphic grade coal drying and dewatering process |
| LU91450B1 (en) * | 2008-06-02 | 2009-12-03 | Wurth Paul Sa | Method for producing pulverized coal |
| LU91451B1 (en) * | 2008-06-02 | 2009-12-03 | Wurth Paul Sa | Method for producing pulverized coal |
| CN101440323B (en) * | 2008-10-31 | 2012-07-18 | 大唐国际化工技术研究院有限公司 | Drying and moulding integrated process for low rank coal |
| DE102010036176A1 (en) | 2010-09-02 | 2012-03-08 | Loesche Gmbh | Method and plant for coal grinding in inert or non-inert operation |
| EA201300534A1 (en) * | 2010-12-16 | 2013-08-30 | Лёше Гмбх | METHOD OF GRINDING THE GRINDED MATERIAL AND ROLE MILL |
| EP2524729A1 (en) * | 2011-05-20 | 2012-11-21 | Claudius Peters Projects GmbH | Assembly and method for dry-grinding and storing lignite fuel |
| GB2494370B (en) | 2011-05-24 | 2015-02-18 | Coomtech Ltd | System for removing surface moisture from coal |
| WO2013166179A1 (en) | 2012-05-01 | 2013-11-07 | Innovative Combustion Technologies, Inc. | Pulverizer mill protection system |
| US9604226B2 (en) | 2012-05-01 | 2017-03-28 | Innovative Combustion Technologies, Inc. | Pulverizer mill protection system |
| DK2985081T3 (en) | 2014-08-12 | 2017-07-10 | Loesche Gmbh | Process and air flow vertical mill for grinding hot and humid raw material as well as duct-like segment. |
| RU2611848C1 (en) * | 2015-09-14 | 2017-03-01 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Кемеровский технологический институт пищевой промышленности (университет)" | Grinder |
| LU92916B1 (en) * | 2015-12-17 | 2017-07-13 | Wurth Paul Sa | Grinding and drying plant |
| CN105597877A (en) * | 2016-04-11 | 2016-05-25 | 南京富源资源利用有限公司 | Movable type counterattacking crusher with atomization and sound insulation functions |
| CN109269864B (en) * | 2018-12-11 | 2024-09-13 | 长沙开元仪器有限公司 | Coal sample pulverizing equipment |
| CN113102088B (en) * | 2021-04-10 | 2022-08-30 | 南京工程学院 | Full-automatic autonomous centralized control device and method for large-scale blast furnace pulverizing system |
| DE202021002483U1 (en) | 2021-07-26 | 2021-08-05 | Hartmut Ortlieb | Bag or container for attachment to or under a saddle |
| CN114602605B (en) * | 2022-04-15 | 2023-09-15 | 上海沛元农业发展有限公司 | Crushing system for ganoderma lucidum processing |
| CN116078493B (en) * | 2023-01-09 | 2024-01-19 | 山西锦泉环保科技有限公司 | Fine grinding equipment for processing activated carbon |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3734359A1 (en) * | 1987-10-10 | 1989-04-20 | Rheinische Braunkohlenw Ag | Method for producing brown-coal dust |
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|---|---|---|---|---|
| US2909330A (en) * | 1954-09-30 | 1959-10-20 | Hardinge Harlowe | Pulverizing mill and process of pulverizing material |
| DE2361060B2 (en) * | 1973-12-07 | 1978-05-11 | Loesche Hartzerkleinerungs- Und Zementmaschinen Kg, 4000 Duesseldorf | Plant and process for the production of cement |
| DD141791A1 (en) * | 1977-11-09 | 1980-05-21 | Helmut Engelmann | HOUSING TOP FOR ROLLING MILLS |
| DE3100341A1 (en) * | 1981-01-08 | 1982-07-22 | Loesche GmbH, 4000 Düsseldorf | ROLL MILL, ESPECIALLY FOR COAL GRINDING |
| US4545132A (en) * | 1984-04-06 | 1985-10-08 | Atlantic Richfield Company | Method for staged cooling of particulate solids |
| DE3415072A1 (en) * | 1984-04-21 | 1985-10-24 | Deutsche Babcock Werke AG, 4200 Oberhausen | Centrifugal pendulum-type mill |
| DE3418196A1 (en) * | 1984-05-16 | 1985-11-21 | Krupp Polysius Ag, 4720 Beckum | RINGMILL WITH ADJUSTABLE NOZZLE RING |
| JPS62262705A (en) * | 1986-05-07 | 1987-11-14 | Agency Of Ind Science & Technol | Hydrophilic porous membrane, its production and serum separator using said membrane |
| US4932594A (en) * | 1987-10-06 | 1990-06-12 | The Babcock & Wilcox Company | Pulverized coal flow control system |
| DE3741611A1 (en) * | 1987-12-09 | 1989-06-22 | Babcock Werke Ag | ROLL BOWL MILL |
| US4817441A (en) * | 1988-05-02 | 1989-04-04 | O'donnell & Associates, Inc. | Process and apparatus for obtaining a gas sample |
-
1992
- 1992-07-14 DE DE4223151A patent/DE4223151C2/en not_active Expired - Lifetime
-
1993
- 1993-07-13 RU RU93049643A patent/RU2109569C1/en active
- 1993-07-13 US US08/091,835 patent/US5353997A/en not_active Expired - Lifetime
- 1993-07-14 AU AU41930/93A patent/AU663790B2/en not_active Expired
- 1993-07-14 ES ES93111318T patent/ES2102557T5/en not_active Expired - Lifetime
- 1993-07-14 CN CN93116775A patent/CN1033218C/en not_active Expired - Lifetime
- 1993-07-14 EP EP93111318A patent/EP0579214B2/en not_active Expired - Lifetime
- 1993-07-14 CA CA002100490A patent/CA2100490A1/en not_active Abandoned
- 1993-07-14 SK SK740-93A patent/SK279856B6/en unknown
- 1993-07-14 CZ CZ931400A patent/CZ283804B6/en not_active IP Right Cessation
- 1993-07-14 DE DE59306716T patent/DE59306716D1/en not_active Expired - Lifetime
-
1997
- 1997-07-16 GR GR970401767T patent/GR3024117T3/en unknown
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3734359A1 (en) * | 1987-10-10 | 1989-04-20 | Rheinische Braunkohlenw Ag | Method for producing brown-coal dust |
Non-Patent Citations (1)
| Title |
|---|
| Firmenprospekt "Wälzmühlen-Roller Grinding Mills" der Loesche GmbH, 2/84 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CZ283804B6 (en) | 1998-06-17 |
| ES2102557T5 (en) | 2005-04-16 |
| GR3024117T3 (en) | 1997-10-31 |
| EP0579214A1 (en) | 1994-01-19 |
| AU663790B2 (en) | 1995-10-19 |
| US5353997A (en) | 1994-10-11 |
| CZ140093A3 (en) | 1994-03-16 |
| CA2100490A1 (en) | 1994-01-15 |
| EP0579214B2 (en) | 2004-08-25 |
| CN1092700A (en) | 1994-09-28 |
| DE4223151A1 (en) | 1994-01-20 |
| RU2109569C1 (en) | 1998-04-27 |
| SK74093A3 (en) | 1994-02-02 |
| CN1033218C (en) | 1996-11-06 |
| ES2102557T3 (en) | 1997-08-01 |
| SK279856B6 (en) | 1999-04-13 |
| DE59306716D1 (en) | 1997-07-17 |
| AU4193093A (en) | 1994-02-03 |
| DE4223151C2 (en) | 1994-11-10 |
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